Author(s)：Xing Tang, Steven Wood, Larissa Baeva
Affiliation(s)
Division of Biology, OSEL/CDRH/FDA.
Division of Biology, OSEL/CDRH/FDA.
Division of Biology, OSEL/CDRH/FDA.
ABSTRACT
A modified low denaturing temperature PCR (LDT-PCR) method combined with DNA microarray technique is developed in our lab for quick and effective identification of various mutations in an 81 base pair region of Mycobacterium Tuberculosis (MTB) ribosome RNA polymerase subunit B (rpoB) gene associated with rifampin resistance. By incurporation of wild type (wt) allele fragments that had been PCR amplified previously, the target PCR fragments coming from mutant clinical MTB samples were codenaturized with incorporated wt type allele fragment at 94°C and then let them randomly form matched structures (homoduplex) and allele mismatch-containing structures (heteroduplex), respectively, when the temperature cooled down to 70°C. After the temperature was raised to 80°C, the heteroduplex double stranded fragments were preferentially denatured and resulted in PCR amplification as well as fluorescence incurporation. Since the homoduplex fragments need a higher temperature to be denatured, they were kept in double-stranded status at that temperature and failed to be PCR amplified. By hybridization of LDT-PCR products with the probes spotted on microarray slides, the fluorescent signals representing the presence of gene mutations were detected. We have tested this method on 35 clinical MTB samples and obtained satisfied results.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=37052
9/29/2014
Object Detection Using SURF and Superpixels
Author(s)
Patrick R. McMullen
ABSTRACT
This research presents a problem relevant to production scheduling for mixed models – production schedules that contain several unique items, but each unique item may have multiple units that require processing. The presented research details a variant of this problem where, over multiple processes, resequencing is permitted to a small degree so as to exploit efficiencies with the intent of optimizing the objectives of required set-ups and parts usage rate via an efficient frontier. The problem is combinatorial in nature. Enumeration is used on a variety of test problems from the literature, and a search heuristic is used to compare optimal solutions with heuristic based solutions. Experimentation shows that the heuristic solutions approach optimality, but with opportunities for improvement.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=8914
Patrick R. McMullen
ABSTRACT
This research presents a problem relevant to production scheduling for mixed models – production schedules that contain several unique items, but each unique item may have multiple units that require processing. The presented research details a variant of this problem where, over multiple processes, resequencing is permitted to a small degree so as to exploit efficiencies with the intent of optimizing the objectives of required set-ups and parts usage rate via an efficient frontier. The problem is combinatorial in nature. Enumeration is used on a variety of test problems from the literature, and a search heuristic is used to compare optimal solutions with heuristic based solutions. Experimentation shows that the heuristic solutions approach optimality, but with opportunities for improvement.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=8914
9/26/2014
Limited Resequencing for Mixed Models with Multiple Objectives
Author(s): Patrick R. McMullen
ABSTRACT
This research presents a problem relevant to production scheduling for mixed models – production schedules that contain several unique items, but each unique item may have multiple units that require processing. The presented research details a variant of this problem where, over multiple processes, resequencing is permitted to a small degree so as to exploit efficiencies with the intent of optimizing the objectives of required set-ups and parts usage rate via an efficient frontier. The problem is combinatorial in nature. Enumeration is used on a variety of test problems from the literature, and a search heuristic is used to compare optimal solutions with heuristic based solutions. Experimentation shows that the heuristic solutions approach optimality, but with opportunities for improvement.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=8914
ABSTRACT
This research presents a problem relevant to production scheduling for mixed models – production schedules that contain several unique items, but each unique item may have multiple units that require processing. The presented research details a variant of this problem where, over multiple processes, resequencing is permitted to a small degree so as to exploit efficiencies with the intent of optimizing the objectives of required set-ups and parts usage rate via an efficient frontier. The problem is combinatorial in nature. Enumeration is used on a variety of test problems from the literature, and a search heuristic is used to compare optimal solutions with heuristic based solutions. Experimentation shows that the heuristic solutions approach optimality, but with opportunities for improvement.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=8914
Genome sequencing and next-generation sequence data analysis: A comprehensive compilation of bioinformatics tools and databases
Author(s): Jose C. Jimenez-Lopez, Emma W. Gachomo, Sweta Sharma, Simeon O. Kotchoni
ABSTRACT
Genomics has become a ground-breaking field in all areas of the life sciences. The advanced genomics and the development of high-throughput techniques have lately provided insight into whole-genome characterization of a wide range of organisms. In the post-genomic era, new technologies have revealed an outbreak of prerequisite genomic sequences and supporting data to understand genome wide functional regulation of gene expression and metabolic pathways reconstruction. However, the availability of this plethora of genomic data presents a significant challenge for storage, analyses and data management. Analysis of this mega-data requires the development and application of novel bioinformatics tools that must include unified functional annotation, structural search, and comprehensive analysis and identification of new genes in a wide range of species with fully sequenced genomes. In addition, generation of systematically and syntactically unambiguous nomenclature systems for genomic data across species is a crucial task. Such systems are necessary for adequate handling genetic information in the context of comparative functional genomics. In this paper, we provide an overview of major advances in bioinformatics and computational biology in genome sequencing and next-generation sequence data analysis. We focus on their potential applications for efficient collection, storage, and analysis of genetic data/information from a wide range of gene banks. We also discuss the importance of establishing a unified nomenclature system through a functional and structural genomics approach.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=30744
ABSTRACT
Genomics has become a ground-breaking field in all areas of the life sciences. The advanced genomics and the development of high-throughput techniques have lately provided insight into whole-genome characterization of a wide range of organisms. In the post-genomic era, new technologies have revealed an outbreak of prerequisite genomic sequences and supporting data to understand genome wide functional regulation of gene expression and metabolic pathways reconstruction. However, the availability of this plethora of genomic data presents a significant challenge for storage, analyses and data management. Analysis of this mega-data requires the development and application of novel bioinformatics tools that must include unified functional annotation, structural search, and comprehensive analysis and identification of new genes in a wide range of species with fully sequenced genomes. In addition, generation of systematically and syntactically unambiguous nomenclature systems for genomic data across species is a crucial task. Such systems are necessary for adequate handling genetic information in the context of comparative functional genomics. In this paper, we provide an overview of major advances in bioinformatics and computational biology in genome sequencing and next-generation sequence data analysis. We focus on their potential applications for efficient collection, storage, and analysis of genetic data/information from a wide range of gene banks. We also discuss the importance of establishing a unified nomenclature system through a functional and structural genomics approach.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=30744
Is Faster Necessarily Better? 3G Take-Up Rates and the Implications for Next Generation Services
Author(s): Christian M. Dippon
ABSTRACT
Most countries have allocated 3G spectrum and are in the process of allocating advanced wireless services and 4G spectrum, both of which promise subscribers significantly faster broadband speeds. Operators anticipate that subscribers will adopt these services swiftly thereby justifying the large investments. Yet, why is it the case that only two countries in the world have more 3G than 2G subscribers? This study examines the drivers behind 3G diffusion using linear probability models and qualitative choice (logit) analysis. Time series diffusion models show that diffusion patterns follow an s-curve pattern, favoring the Gompertz curve.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=21931
ABSTRACT
Most countries have allocated 3G spectrum and are in the process of allocating advanced wireless services and 4G spectrum, both of which promise subscribers significantly faster broadband speeds. Operators anticipate that subscribers will adopt these services swiftly thereby justifying the large investments. Yet, why is it the case that only two countries in the world have more 3G than 2G subscribers? This study examines the drivers behind 3G diffusion using linear probability models and qualitative choice (logit) analysis. Time series diffusion models show that diffusion patterns follow an s-curve pattern, favoring the Gompertz curve.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=21931
Next generation sequencing for profiling expression of miRNAs: technical progress and applications in drug development
Author(s): Jie Liu, Steven F. Jennings, Weida Tong, Huixiao Hong
ABSTRACT
miRNAs are non-coding RNAs that play a regulatory role in expression of genes and are associated with diseases. Quantitatively measuring expression levels of miRNAs can help understanding the mechanisms of human diseases and discovering new drug targets. There are three major methods that have been used to measure the expression levels of miRNAs: real-time reverse transcription PCR (qRT-PCR), microarray, and the newly introduced next-generation sequencing (NGS). NGS is not only suitable for profiling of known miRNAs that qRT-PCR and microarray can do too but also able to detect unknown miRNAs that the other two methods are incapable. Profiling of miRNAs by NGS has been progressed rapidly and is a promising field for applications in drug development. This paper will review the technical advancement of NGS for profiling miRNAs, including comparative analyses between different platforms and software packages for analyzing NGS data. Examples and future perspectives of applications of NGS profiling miRNAs in drug development will be discussed.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=7910
ABSTRACT
miRNAs are non-coding RNAs that play a regulatory role in expression of genes and are associated with diseases. Quantitatively measuring expression levels of miRNAs can help understanding the mechanisms of human diseases and discovering new drug targets. There are three major methods that have been used to measure the expression levels of miRNAs: real-time reverse transcription PCR (qRT-PCR), microarray, and the newly introduced next-generation sequencing (NGS). NGS is not only suitable for profiling of known miRNAs that qRT-PCR and microarray can do too but also able to detect unknown miRNAs that the other two methods are incapable. Profiling of miRNAs by NGS has been progressed rapidly and is a promising field for applications in drug development. This paper will review the technical advancement of NGS for profiling miRNAs, including comparative analyses between different platforms and software packages for analyzing NGS data. Examples and future perspectives of applications of NGS profiling miRNAs in drug development will be discussed.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=7910
Efficiency of microsatellite isolation from orchids via next generation sequencing
Author(s):Madhav Pandey, Jyotsna Sharma
ABSTRACT
Microsatellites, or simple sequence repeats (SSRs), are highly polymorphic, co-dominant genetic markers commonly used for population genetics analyses although de novo development of species specific microsatellites is cost-and time-intensive. Orchidaceae is one of the most species-rich families of angiosperms with more than 30,000 species estimated. Despite its high species-diversity, microsatellites are available only for a few species and all were developed by only using Sanger sequencing methods. For the first time in orchids, we used 454 GS-FLX sequencing to isolate microsatellites in two species (Cypripedium kentuckiense and Pogonia ophioglossoides), and report preliminary results of the study. From 1/16th plate that was subjected to sequencing, 32,665 reads were generated, from which 15,473 fragments contained at least one SSR. We selected 20,697 SSRs representing di-, tri-, and tetra-nucleotides. While 3,674 microsatellites had flanking regions on both sides, useable primer pairs could be designed for 255 SSRs. The mean numbers of reads, SSRs, and SSR-containing reads useful for primer design estimated for other 15 orchid species using Sanger sequencing method were 166, 78 and 31, respectively. Results demonstrate that the efficiency of microsatellite isolation in orchids is substantially higher with 454 GS-FLX sequencing technique in comparison to the Sanger sequencing methods.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=26308
ABSTRACT
Microsatellites, or simple sequence repeats (SSRs), are highly polymorphic, co-dominant genetic markers commonly used for population genetics analyses although de novo development of species specific microsatellites is cost-and time-intensive. Orchidaceae is one of the most species-rich families of angiosperms with more than 30,000 species estimated. Despite its high species-diversity, microsatellites are available only for a few species and all were developed by only using Sanger sequencing methods. For the first time in orchids, we used 454 GS-FLX sequencing to isolate microsatellites in two species (Cypripedium kentuckiense and Pogonia ophioglossoides), and report preliminary results of the study. From 1/16th plate that was subjected to sequencing, 32,665 reads were generated, from which 15,473 fragments contained at least one SSR. We selected 20,697 SSRs representing di-, tri-, and tetra-nucleotides. While 3,674 microsatellites had flanking regions on both sides, useable primer pairs could be designed for 255 SSRs. The mean numbers of reads, SSRs, and SSR-containing reads useful for primer design estimated for other 15 orchid species using Sanger sequencing method were 166, 78 and 31, respectively. Results demonstrate that the efficiency of microsatellite isolation in orchids is substantially higher with 454 GS-FLX sequencing technique in comparison to the Sanger sequencing methods.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=26308
9/22/2014
Interpretable Housing for Freedom of the Body: The Next Generation of Flexible Homes
Author(s)： Kyung Wook Seo, Chang Sung Kim
ABSTRACT
If we have gone through the first generation of housing design that pursued functional optimization, ergonomics, and circulation efficiency during the last century, now we are living in the second generation where more advanced goals, such as universal design, ubiquitous design, sustainable design, and environment-friendly design, are emphasized. Although this second generation of design focuses upon the wellness of humans in accordance with environment, it still has the attitude that a more precisely designed home can guarantee a better life. What lacks in this approach is the freedom of the body; it needs to make its own choice as to how to use a space. Thus, it is suggested in this paper that what is important in designing a home is to provide alternatives in daily lives so as to make a full exploration of a given space. These alternatives can be made by offering residents an interpretable space where they can figure out space usages and routs in a constantly changing context. Two spatial devices are discussed in depths as a way to realize this interpretable house: room-to-room enfilade and ring spatial structure. By investigating some existing house plans, it is illustrated how they can guarantee the freedom of the body, and thus alternatives for the flexible domestic life.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=37194
ABSTRACT
If we have gone through the first generation of housing design that pursued functional optimization, ergonomics, and circulation efficiency during the last century, now we are living in the second generation where more advanced goals, such as universal design, ubiquitous design, sustainable design, and environment-friendly design, are emphasized. Although this second generation of design focuses upon the wellness of humans in accordance with environment, it still has the attitude that a more precisely designed home can guarantee a better life. What lacks in this approach is the freedom of the body; it needs to make its own choice as to how to use a space. Thus, it is suggested in this paper that what is important in designing a home is to provide alternatives in daily lives so as to make a full exploration of a given space. These alternatives can be made by offering residents an interpretable space where they can figure out space usages and routs in a constantly changing context. Two spatial devices are discussed in depths as a way to realize this interpretable house: room-to-room enfilade and ring spatial structure. By investigating some existing house plans, it is illustrated how they can guarantee the freedom of the body, and thus alternatives for the flexible domestic life.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=37194
The Internet of Things and Next-generation Public Health Information Systems
Author(s)：Robert Steele, Andrew Clarke
ABSTRACT
The Internet of things has particularly novel implications in the area of public health. This is due to (1) The rapid and widespread adoption of powerful contemporary Smartphone’s; (2) The increasing availability and use of health and fitness sensors, wearable sensor patches, smart watches, wireless-enabled digital tattoos and ambient sensors; and (3) The nature of public health to implicitly involve connectivity with and the acquisition of data in relation to large numbers of individuals up to population scale. Of particular relevance in relation to the Internet of Things (IoT) and public health is the need for privacy and anonymity of users. It should be noted that IoT capabilities are not inconsistent with maintaining privacy, due to the focus of public health on aggregate data not individual data and broad public health interventions. In addition, public health information systems utilizing IoT capabilities can be constructed to specifically ensure privacy, security and anonymity, as has been developed and evaluated in this work. In this paper we describe the particular characteristics of the IoT that can play a role in enabling emerging public health capabilities; we describe a privacy-preserving IoT-based public health information system architecture; and provide a privacy evaluation.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=38011
ABSTRACT
The Internet of things has particularly novel implications in the area of public health. This is due to (1) The rapid and widespread adoption of powerful contemporary Smartphone’s; (2) The increasing availability and use of health and fitness sensors, wearable sensor patches, smart watches, wireless-enabled digital tattoos and ambient sensors; and (3) The nature of public health to implicitly involve connectivity with and the acquisition of data in relation to large numbers of individuals up to population scale. Of particular relevance in relation to the Internet of Things (IoT) and public health is the need for privacy and anonymity of users. It should be noted that IoT capabilities are not inconsistent with maintaining privacy, due to the focus of public health on aggregate data not individual data and broad public health interventions. In addition, public health information systems utilizing IoT capabilities can be constructed to specifically ensure privacy, security and anonymity, as has been developed and evaluated in this work. In this paper we describe the particular characteristics of the IoT that can play a role in enabling emerging public health capabilities; we describe a privacy-preserving IoT-based public health information system architecture; and provide a privacy evaluation.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=38011
Ultrasensitive Detection of Glyphosate Using CdTe Quantum Dots in Sol-Gel-Derived Silica Spheres Coated with Calix[6]arene as Fluorescent Probes
Author(s) ：Tao Li, Yunyou Zhou, Junyong Sun, Kai Wu
ABSTRACT
We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=16796
ABSTRACT
We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=16796
Next Generation Optical Access Network Using CWDM Technology
Author(s)：Saba Al-RUBAYE, Anwer AL-DULAIMI, Hamed Al-RAWESHIDY
ABSTRACT
We are developing a novel technology for the next generation optical access network. The proposed archi-tecture provides FTTX high bandwidth which enables to give out 10Gbit/s per end-user. Increasing the subscribers in the future will cause massive congestion in the data transferred along the optical network. Our solution is using the wavelength division multiplexing PON (CWDM-PON) technology to achieve high bandwidth and enormous data transmission at the network access. Physical layer modifications are used in our model to provide satisfactory solution for the bandwidth needs. Thus high data rates can be achieved throughout the network using low cost technologies. Framework estimations are evaluated to prove the intended model success and reliability. Our argument that: this modification will submit a wide bandwidth suitable for the future Internet.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=770
ABSTRACT
We are developing a novel technology for the next generation optical access network. The proposed archi-tecture provides FTTX high bandwidth which enables to give out 10Gbit/s per end-user. Increasing the subscribers in the future will cause massive congestion in the data transferred along the optical network. Our solution is using the wavelength division multiplexing PON (CWDM-PON) technology to achieve high bandwidth and enormous data transmission at the network access. Physical layer modifications are used in our model to provide satisfactory solution for the bandwidth needs. Thus high data rates can be achieved throughout the network using low cost technologies. Framework estimations are evaluated to prove the intended model success and reliability. Our argument that: this modification will submit a wide bandwidth suitable for the future Internet.
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=770
Cardiac Toxicity of Azole Antifungals
Author(s) ：John D. Cleary, Kayla R. Stover, Jerry Farley, William Daley, Patrick B. Kyle, Jon Hosler
Cardiac toxicity is an uncommon side effect of anti-fungal therapy. Until the recent reports of itraconazole (ITZ) associated cardiac failure, amphotericin was the antifungal most frequently reported with arrhythmias. We evaluated the cardiac effect of azole antifungals, specifically ITZ, and possible mechanisms of toxicity. Ex vivolive-heart studies were performed utilizing Sprague Dawley rats. Short exposure (<5 minutes), random crossover, dose ranging studies were performed with each pharmacologic agent. ITZ focused trials also included dose ranging utilizing a non-crossover design. The only azole found to have significant toxicity was ITZ. At ITZ ~ ED25 (2 - 2.5 ug/mL) exposures, contractility decreased by 22.2% ± 15.7% and amplitude of left ventricular pressure decreased by 11% ± 0.17%. Electron micrograph and alterations in mitochondrial respiration suggest mitochondrial toxicity as an underlying mechanism. In conclusion, ITZ was associated with reductions in contractility, possibly secondary to mitochondrial dysfunction and dilated cardiomyopathy.
9/17/2014
Suppression of Pyrite Oxidation by Surface Silica Coating
Author(s): K. Kollias, E. Mylona, K. Adam, N. Papassiopi, N. Papassiopi, A. Xenidis
ABSTRACT
The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si,
1. Introduction Acid mine drainage (AMD) constitutes one of the most severe environmental problems of the mining industry. AMD which is a low-pH aqueous phase enriched primarily in iron (Fe) and sulfate anions, but also containing many metals and metalloids, such as lead (Pb), copper (Cu), zinc (Zn), manganese (Mn), nickel (Ni), cadmium (Cd), mercury (Hg) etc., depending on the mineralogy of the ore/waste. These acidic waters are produced by the oxidation of sulphide minerals, contained in the mine wastes and rocks, under the action of atmospheric air and water and catalyzed by the presence of bacteria. Singer & Stumm (1970) described the pyrite oxidation, which may occur via direct and indirect mechanisms, according to the following reactions:
Once generation of acidic waters commences, the sources of acidity may remain active for a long time after the mine closure. So, the effects of AMD can be both pernicious and far-reaching since contamination of surface and/or underground water can carry the pollution considerable distances from the mining area. The acidic drainages are treated by conventional reclamation techniques, such as addition of alkaline materials (mainly, limestone and lime), covering with water to prevent oxygen access or formation of low permeability soil covers to minimize oxidizing agents transfer to the sulphides. Apart from the conventional prevention and remediation methods, an emerging and appealing technique for the inhibition of acid generation from sulphidic wastes involves the development of artificial coatings on sulphide grain surfaces (particularly on pyrite grains due to the abundance to all geological environments). This process is known as microencapsulation and was first described by Evangelou (1995a, 1995b), investigating the formation of phosphate coating on pyrite surfaces.
Other published studies refer to the establishment of coatings using inorganic materials, FeOOH (Huminicki & Rimstidt, 2009), silicates (Zhang & Evangelou, 1998; Evangelou, 2001) and magnesium and manganese compounds (Glover, 2007) and organic coatings such as humic acid and other organic ligands (Lalvani et al., 1996; Elsetinow et al., 2003; Kargbo et al., 2004).
The methodology, which was developed for the formation of silicic coating includes partial leaching/oxidetion of the sulphidic waste using a solution containing hydrogen peroxide (H2O2), a silica source and adjusted to pH 4.0 - 6.0 (Evangelou, 1996).
According to the study of Evangelou (2001), pyrite treatment with a solution consisting of H2O2 0.145 M, Si 0.0018 M, CH3COONa 0.01 M, NaCl 0.1 M and adjusted to pH 6 at room temperature results in the formation of a silica coating composed of an inner layer of Fe3+ oxy-hydroxides and an outer layer of Si hydroxides. The coating process reduced by 85% the amount of oxidized pyrite compared to the control test. Bessho et al. (2011) performed batch-type tests and an effective silica coating was established on the pyrite surfaces, after treatment with a solution of Si concentration higher than 2500 mg/L and pH: 7.0.
However, coating technology needs further investigation. In this study, batch-type tests were performed in order to investigate the effect of pH and silica concentration on the formation of silica coating on the grains of a pyrite concentrate material.
more:http://www.scirp.org/journal/PaperInformation.aspx?PaperID=47770
ABSTRACT
The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si,
1. Introduction Acid mine drainage (AMD) constitutes one of the most severe environmental problems of the mining industry. AMD which is a low-pH aqueous phase enriched primarily in iron (Fe) and sulfate anions, but also containing many metals and metalloids, such as lead (Pb), copper (Cu), zinc (Zn), manganese (Mn), nickel (Ni), cadmium (Cd), mercury (Hg) etc., depending on the mineralogy of the ore/waste. These acidic waters are produced by the oxidation of sulphide minerals, contained in the mine wastes and rocks, under the action of atmospheric air and water and catalyzed by the presence of bacteria. Singer & Stumm (1970) described the pyrite oxidation, which may occur via direct and indirect mechanisms, according to the following reactions:
Once generation of acidic waters commences, the sources of acidity may remain active for a long time after the mine closure. So, the effects of AMD can be both pernicious and far-reaching since contamination of surface and/or underground water can carry the pollution considerable distances from the mining area. The acidic drainages are treated by conventional reclamation techniques, such as addition of alkaline materials (mainly, limestone and lime), covering with water to prevent oxygen access or formation of low permeability soil covers to minimize oxidizing agents transfer to the sulphides. Apart from the conventional prevention and remediation methods, an emerging and appealing technique for the inhibition of acid generation from sulphidic wastes involves the development of artificial coatings on sulphide grain surfaces (particularly on pyrite grains due to the abundance to all geological environments). This process is known as microencapsulation and was first described by Evangelou (1995a, 1995b), investigating the formation of phosphate coating on pyrite surfaces.
Other published studies refer to the establishment of coatings using inorganic materials, FeOOH (Huminicki & Rimstidt, 2009), silicates (Zhang & Evangelou, 1998; Evangelou, 2001) and magnesium and manganese compounds (Glover, 2007) and organic coatings such as humic acid and other organic ligands (Lalvani et al., 1996; Elsetinow et al., 2003; Kargbo et al., 2004).
The methodology, which was developed for the formation of silicic coating includes partial leaching/oxidetion of the sulphidic waste using a solution containing hydrogen peroxide (H2O2), a silica source and adjusted to pH 4.0 - 6.0 (Evangelou, 1996).
According to the study of Evangelou (2001), pyrite treatment with a solution consisting of H2O2 0.145 M, Si 0.0018 M, CH3COONa 0.01 M, NaCl 0.1 M and adjusted to pH 6 at room temperature results in the formation of a silica coating composed of an inner layer of Fe3+ oxy-hydroxides and an outer layer of Si hydroxides. The coating process reduced by 85% the amount of oxidized pyrite compared to the control test. Bessho et al. (2011) performed batch-type tests and an effective silica coating was established on the pyrite surfaces, after treatment with a solution of Si concentration higher than 2500 mg/L and pH: 7.0.
However, coating technology needs further investigation. In this study, batch-type tests were performed in order to investigate the effect of pH and silica concentration on the formation of silica coating on the grains of a pyrite concentrate material.
more:http://www.scirp.org/journal/PaperInformation.aspx?PaperID=47770
Dust Suppression with Glycerin from Biodiesel Production: A Review
Author(s): Wei Yan, S. Kent Hoekman
ABSTRACT
An increasing number of countries and areas in the world suffer from either natural or anthropogenic dust, which results in a serious hazard with respect to the environment and to personal health and safety. This paper reviews and summa- rizes open literature involving the use of glycerin in dust control applications. Glycerin, a by-product from biodiesel manufacturing, has been evaluated for dust suppressant performance when applied alone as aqueous solutions, or in combinations with surfactants, polymers, or other chemicals. There are reports indicating that glycerin is effective in some dust suppression applications, although details about its use and performance metrics are generally lacking. Re- cent growth of the biodiesel industry has significantly increased the supply of crude glycerin, making it an economically attractive material for use in dust suppression. This paper also highlights several environmental accidents caused by irresponsible discharges of crude glycerin, and points out the need to understand environmental consequences of gly- cerin and its impurities when used in dust suppression applications.
1. Introduction
Sources of dust, including tephra, occur globally, but the major source regions lie in and around the extremely arid to semi-arid dryland of the world. The largest of these stretches over 10,000 km, from the western Sahara in North Africa, through the Middle East, to central and eastern Asia [1,2].
Sources of erodible natural dust are found in wadis, salt pans, and alluvial deposits, as well as in ephemeral, saline, and dry lakes through North Africa, the Middle East, the northwestern Indian subcontinent, central Asia, and northwestern China. The extent to which particles are taken up from the ground surface depends on several factors: the critical wind speed necessary to dislodge particles (known as the threshold velocity); the instability of the atmosphere; particle size; the degree of particle exposure; vegetation cover; and the mineralogical composition of loose dust on the ground surface [1,2].
Human activities also generate substantial amounts of dust. Anthropogenically disturbed land can become major dust sources, especially in the drought-stricken agricultural regions of Africa, Australia, China, and the U.S. Midwest. Estimates of the magnitude of anthropogenic contributions to global dust load range from less than 10 wt% to 50 wt%, a range of variation that reflects modeling uncertainties and a dearth of measured observational data. More recently, however, direct measurements with satellite-borne spectroradiometers, combined with surface land-use data, show that in regions where 5% - 25% of the land surface is disturbed, more than half the territory is potentially an anthropogenic dust source [1-3].
Mineral dust is composed of variable amounts of quartz, feldspars, micas, various clay minerals, carbonates, oxides and evaporative minerals. Minerals in dust occur as individual grains, aggregates or surface coatings—from less than 1 µm to ~30 µm in diameter. Dust entrainment by saltation and suspension processes takes place mostly when winds are strong and gusty. Freshly entrained dust may initially have a mineral composition similar to that of the surface soil. Particle segregation and deposition of coarse materials takes place over short distances, depending on the mineralogical composition and the physical properties of the dust. Fine and low-density particles remain in suspension and are lofted into the upper troposphere, where they can circle the globe. Airborne dust also carries micro fauna, including diatoms, bacteria and viruses; some of the latter remain alive despite being transported for distances of several thousand kilometers [4]. African dust outbreaks are partly responsible for exceeding the maximum particle concentrations permitted by air quality guidelines in southern Europe.
Fugitive dust from dirt surfaces, and the handling of bulk products with attendant particulate materials, can generate significant health, environmental and safety problems. In mining facilities, industrial sites and construction sites, the operations may be significantly restricted by dust cloud formation. Also health, environmental and safety problems may arise when any kind of dust is inhaled [2-4].
more: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=17468
ABSTRACT
An increasing number of countries and areas in the world suffer from either natural or anthropogenic dust, which results in a serious hazard with respect to the environment and to personal health and safety. This paper reviews and summa- rizes open literature involving the use of glycerin in dust control applications. Glycerin, a by-product from biodiesel manufacturing, has been evaluated for dust suppressant performance when applied alone as aqueous solutions, or in combinations with surfactants, polymers, or other chemicals. There are reports indicating that glycerin is effective in some dust suppression applications, although details about its use and performance metrics are generally lacking. Re- cent growth of the biodiesel industry has significantly increased the supply of crude glycerin, making it an economically attractive material for use in dust suppression. This paper also highlights several environmental accidents caused by irresponsible discharges of crude glycerin, and points out the need to understand environmental consequences of gly- cerin and its impurities when used in dust suppression applications.
1. Introduction
Sources of dust, including tephra, occur globally, but the major source regions lie in and around the extremely arid to semi-arid dryland of the world. The largest of these stretches over 10,000 km, from the western Sahara in North Africa, through the Middle East, to central and eastern Asia [1,2].
Sources of erodible natural dust are found in wadis, salt pans, and alluvial deposits, as well as in ephemeral, saline, and dry lakes through North Africa, the Middle East, the northwestern Indian subcontinent, central Asia, and northwestern China. The extent to which particles are taken up from the ground surface depends on several factors: the critical wind speed necessary to dislodge particles (known as the threshold velocity); the instability of the atmosphere; particle size; the degree of particle exposure; vegetation cover; and the mineralogical composition of loose dust on the ground surface [1,2].
Human activities also generate substantial amounts of dust. Anthropogenically disturbed land can become major dust sources, especially in the drought-stricken agricultural regions of Africa, Australia, China, and the U.S. Midwest. Estimates of the magnitude of anthropogenic contributions to global dust load range from less than 10 wt% to 50 wt%, a range of variation that reflects modeling uncertainties and a dearth of measured observational data. More recently, however, direct measurements with satellite-borne spectroradiometers, combined with surface land-use data, show that in regions where 5% - 25% of the land surface is disturbed, more than half the territory is potentially an anthropogenic dust source [1-3].
Mineral dust is composed of variable amounts of quartz, feldspars, micas, various clay minerals, carbonates, oxides and evaporative minerals. Minerals in dust occur as individual grains, aggregates or surface coatings—from less than 1 µm to ~30 µm in diameter. Dust entrainment by saltation and suspension processes takes place mostly when winds are strong and gusty. Freshly entrained dust may initially have a mineral composition similar to that of the surface soil. Particle segregation and deposition of coarse materials takes place over short distances, depending on the mineralogical composition and the physical properties of the dust. Fine and low-density particles remain in suspension and are lofted into the upper troposphere, where they can circle the globe. Airborne dust also carries micro fauna, including diatoms, bacteria and viruses; some of the latter remain alive despite being transported for distances of several thousand kilometers [4]. African dust outbreaks are partly responsible for exceeding the maximum particle concentrations permitted by air quality guidelines in southern Europe.
Fugitive dust from dirt surfaces, and the handling of bulk products with attendant particulate materials, can generate significant health, environmental and safety problems. In mining facilities, industrial sites and construction sites, the operations may be significantly restricted by dust cloud formation. Also health, environmental and safety problems may arise when any kind of dust is inhaled [2-4].
more: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=17468
Improvement of Antenna Radiation Efficiency by the Suppression of Surface Waves
The characteristics of coplanar waveguide (CPW) fed ring antennas (such as gain, efficiency and polarization purity) are degraded by the dielectric losses and excitation of surface waves on the substrates. To counteract such effects, we propose to remove some portions of the substrate in the vicinity of the metallic patches, which effectively eliminates the conditions for the generation of surface waves. The proposed technique is applied to a CPW-fed ring antenna and a prototype model is fabricated. The measurement data and the computer simulation results agree well and indicate the efficacy of the technique for the improvement of antenna gain and efficiency.
It is desirable to improve the antenna radiation efficiency by using suitable methods to decrease the substrate dielectric losses and limit the spurious surface waves. Although the dissipation losses of available substrates are usually low, the excitation of surface waves degrades the printed antenna performance such as polarization purity and radiation efficiency [1-3]. The surface waves are always present, because the cut-off frequency of their dominant mode is zero. Surface waves move towards the antenna edges, where they radiate into space. Consequently, it is advisable to devise some techniques to suppress the surface waves and prevent them from deteriorating the antenna efficiency and generating cross-polarized fields which spoil the antenna characteristics and polarization purity.
In this paper, we propose to remove the substrate in the neighborhood of the antenna, which counteracts the conditions for the excitation of surface waves. The proposed technique is applied to a printed CPW-fed ring antenna. A prototype model of the proposed antenna is fabricated and its Characteristics are measured and compared with computer simulation results.
Advancements in Suppression of Osteosarcoma Tumorigenicity: A Prospective Look
Bone morphogenetic proteins (BMPs) promote differentiation of stem cells into bone cells. Results from our pilot studies indicate these proteins are also capable of inducing the differentiation of stem-like cells that initiate and propagate osteosarcoma, a rare, highly malignant primary bone tumor affecting primarily children and adolescents. Our plans to evaluate the use of BMP as adjuvant therapy to suppress bone tumor while facilitating skeletal reconstruction are reviewed.
Osteosarcoma (OSA) is an aggressive primary bone cancer primarily affecting children and adolescents, having significant impact on quality of life and survival. Classic OSA is a rare (0.2% of all malignant tumors) and highly malignant tumor, with an estimated incidence of 3 cases/ million population/year [1]. While surgical amputation of an affected limb may contribute to improved survival, patients suffer psychosocial and ambulatory consequences that can be particularly troubling to the adolescent population most affected by this disease [2]. Alternatively, regional resection of symptomatic bone tumors may be successfully performed if adequate stabilization of the structural support impaired by tumor resection can be achieved by bony fusion. Unfortunately, these patients also typically undergo radiation therapy, which negatively impacts bony fusion. Even without radiation, bony fusion can be difficult to achieve with standard fusion/ fixation techniques.
While the use of recombinant human bone morphogenetic proteins (BMPs) has been approved by the FDA to augment spinal fusion and recalcitrant long-bone nonunions, the use of BMP-2 is contraindicated in surgery for bone/spinal tumors due to concerns that this anabolic growth factor may contribute to tumor cell proliferation. Even though surgeons are eager to explore the feasibility of using BMP to facilitate skeletal reconstruction in bone tumor cases, studies to elucidate or support this application are relatively limited.
The inherent complexity of these tumors, especially in the context of the growth-factor-rich bone microenvironment, indicates the need for additional studies to allay this critical concern before clinical use of BMP for OSA treatment can be implemented. Recent evidence suggests the existence of cancer stem cells that are capable of reconstituting tumors hierarchically, postulating a new paradigm for the origin of cancer and its propagation [3-6]. Our early work also identified such tumor-initiating cells in OSA, which possess the abilities to form spherical colonies in an anti-adhesive environment, the plasticity to differentiate into multiple lineages, significant high-level expression of the 3 master genes Oct3/4A, Nanog, and Sox-2 that regulate stem cell characteristics, and an overwhelming propensity to reconstitute tumor subcutaneously and orthotopically (Figure 1), even with as few as 100 cells (Table 1) [7,8]. All of these characteristics have been referred to as stem cell attributes in cancer cells, and found to be highly correlated with high-level activity of aldehyde dehydrogenase (ALDH), an enzyme recently found to be highly active in stem and progenitor cells due to its link to retinoid metabolism that participates in terminal differentiation as well as self-renewal of certain cell types including various cancer stem cells [8-14].
Intriguingly, the results from our work indicate that BMP-2 is effective for inducing tumor-initiating cells associated with high levels of ALDH―namely ALDHbr cells―in the primary bone tumor, to express osteogenic phenotypes without stimulating proliferation, thereby drastically restricting tumor formation and expansion.
Figure 1. The astounding tumorigenicity of ALDHbr cells was evident when these cells were inoculated at orthotopic sites. (a) When 10,000 ALDHbr cells were injected into tibiae of NOD/SCID mice, obvious osteolytic tumor lesions were identified radiographically at implantation site. In contrast, no tumors were noted in contra-lateral limbs injected with the same number of ALDHlo cells. Histology sections documented that (b) intact bone structure was present at ALDHlo cell injection site, whereas (c) malignant cells were present in tumor formed by ALDHbr cells.
Table 1. Tumor formation ability of ALDHbr cell population sorted from the primary OS99-1 xenograft.
Cell proliferation was significantly inhibited at 48 hours when ALDHbr cells were treated with 300 ng/mL BMP-2. Expression of key stem cell marker genes Oct3/4A, Nanog, and Sox-2 were all significantly lowered, and expression of phosphorylated Smad proteins 1, 5, 8 were significantly elevated in BMP-2-treated ALDHbr cells compared to controls (data not shown). This was followed by upregulated expression of transcriptional factor RUNX2 that is essential for osteoblastic differentiation and skeletal morphogenesis, as well as type I collagen as an early marker of bone turnover, suggesting that BMP-2 may induce osteogenic differentiation of the targeted cells [15]. Subcutaneously, development of tumors formed by inoculated ALDHbr cells dramatically ceased when 30 μg BMP-2 was administered at the lesion site in all experimental animals, with few Ki-67-positive cells present. Systemic as well as local skeletal consequences were also evaluated to ensure overall safety and efficacy of BMP-2. When human OSA cells were injected into the tibia medullary cavity of mice via intercondylar eminence to develop human OSA orthotopically, intact bone structure with no malignant cells was observed in histology sections of the limb injected with BMP-2, whereas malignant cells were dispersed over the entire intervened site along with fragmented bone matrix in the contra-lateral limb site injected with untreated tumor cells (Figures 2(a)-(c)). Osteogenesis induced by BMP2 in OSA seems to be a synergy from both ALDHbr and ALDHlo subsets. When exposed to BMP-2, heterogenous ALDHlo progenies were induced to generate structured, calcified bone tissue in vivo with the morphological appearance of bone matrix deposition and marrow substances in the de novo bone tissue (Figures 2(d) and (e)), while tissue nodules of much smaller size were retrieved from the contra-lateral side where the same amount of ALDHbr cells were injected with BMP-2 (Figures 2(f) and (g)).
Using BMP-2 to inhibit tumorigenesis of ALDHbr cells thus appears to give great promise for suppressing or even autogenously eliminating bone tumors. We hypothesize that BMP-2 induction reduces the tumorigenic capacity of OSA while promoting osseous reunion of the intervened skeleton to facilitate surgical reconstruction after tumor resection. In particular, BMP-2 restricts the
Figure 2. Suppression of OSA tumor growth by BMP-2. Unsorted human OSA-derived cells were introduced into the tibia medullary cavity via intercondylar eminence to develop human OSA orthotopically in mice as previously reported, either with or without concurrent BMP-2 application. (a) Twenty days after injection, bone tumor formation was noted with radiographic evidence of osteolysis at the site injected with untreated OSA cells. In contrast, no tumor was observed in the contralateral limb where cells were transplanted along with BMP-2; (b) Intact bone structure with no malignant cells was observed in histology sections of limb injected with BMP-2; whereas (c) malignant cells were dispersed over the entire intervened site along with fragmented bone matrix at the contra-lateral limb site injected with untreated tumor cells. Induced osteogenesis was contributed by both ALDHbr cells and their ALDHlo progenies; (d) The 3-dimensionally rendered micro-CT illustrates that BMP-2 induced ALDHlocells to form well-structured bone nodule with an outer cortical shell containing inner cancellous bone; (e) Hematoxylin and eosin staining further confirmed the morphological appearance of bone matrix deposition and marrow substances in de novo bone tissue; (f, g) Tissue nodules of much smaller size were retrieved from the contra-lateral side where the same amount of ALDHbr cells were injected with BMP-2, as also characterized radiographically and histologically. Cells were more differentiated and actively participated in bone tissue formation compared to those untreated ALDHbr cells in the earlier experiment that eventually appeared malignant.
Figure 3. Schematic illustration of postulated hierarchical impact of BMP-2 in the heterogeneous tumor population of OSA.
tumorigenicity of OSA by inducing “differentiation” of the osteosarco-stem cells that express high levels of ALDH. Although our current work indicates that exposure to BMP-2 activates the Smad pathway in ALDHbr cells, which in turn promotes expression of certain key markers of osteogenic differentiation, more extensive characterizations will be conducted to investigate the final fate and behaviors of the induced cells. Moreover, we will use a canine spontaneous OSA model to evaluate if BMP treatment reduces tumor recurrence orthotopically while promoting stability of the intervened skeleton by induced bone augmentation as a preclinical investigation that replicates clinical scenarios.
We hope to demonstrate that the use of BMP as an adjuvant therapy to treat bone cancer would be of great benefit and provide sound support to facilitate development of a new strategy to augment limb-sparing treatments already in clinical use. Our concept of treating OSA with BMP-2, which is clinically available, not only meets the urgent need to seek potential therapeutics that are ready for application, but also uses the model cancer stem cell hypothesis to contribute new insight into hierarchical impacts to the heterogeneous population by the delivered cytokine, providing a new framework for treating OSA (Figure 3).
Participation of Morphofunctional Zones in Aging Processes
There are morphofunctional zones in organism tissues, where proliferation and differentiation processes occur. Daughter cells are differentiated in the electric field excited by 12 mother and daughter cell pairs, which turned out at cambial cell division. With aging, the cambial cell number is reduced to 7, which is close to threshold level (6 cells), at which the differentiation of daughter cells is absent. The depression of cambial cell number with aging is connected with the work of another morphofunctional zone—the hypothalamus, which is the major center of vegetative regulation and initially has very high RhoA activity, which has been established in embryogenesis. Estrogens, influencing over the hypothalamus and activating Src kinase in its nuclei, reduce level of RhoA activity, including SCN, responsible for many biorhythms of an organism. As a result, the hyperestrogenemia and therefore a connective tissue at first occur. Then there happens a hypoestrogenemia that leads to sharp falling of proliferative activity of cells, causing the depression of cambial cell number and possibility of a malignant tumor development. Along with this, there are the deep lesions of hormone regulation, leading to some lethal diseases. Thus, the RhoA increasing in hypothalamus and especially in SCN circadian rhythm can counteract the Src kinase intensifying and prevent the processes connected with this.
Aging and the primary cosmetic nasal surgery
Purpose: The main goal of this article is to review the literature of general health and nasal anatomical-physiological profile of the elderly, prior to considering them as a candidate for primary cosmetic rhinoplasty (PCR). Rhinoplasty is the cosmetic nose’s surgical alteration. Materials and Methods: We extracted the information from internet search engines and the End Note software version X7. Criteria were applied to the most appropriate clinical messages related to the elderly. We focused on their general health status and their nasal anatomicalphysiological considerations prior to consider them for undergoing PCR. Research links were mostly from the Pub Med and the Medline databases. Results: the literature review showed that as people age, their health status and anatomical-physiological components of their nose alter. Their nasal anatomical supports get weaker, and their nasal internal and external physiology undergoes modifications. Functions related to the nasal supports, normal physiology of smell, airway passage, humidification mechanism and their general appearances are affected by age. Conclusion: Cosmetic surgeons must be aware of the aforementioned changes of the patients’ past and present health. Considering performing a complete systemic evaluation and the nasal anatomical-physical examination to assess the degrees of alterations, are crucial pre-operatively.
Accelerated Aging in Tomato Seeds
Author(s): Andreia da Silva Almeida, Cristiane Deuner, Carolina Terra Borges, Geri Eduardo Meneghello, Lilian Madruga de Tunes, Francisco Amaral Villela
The tomato plant (Lycopersicum esculentum L.) is a perennial, shrubby-like vegetable with high reproductive ability, which behaves like a typical annual crop. The aim of this work was to select suitable tests to assess the quality of different lots of tomato seeds. Six batches of tomato seeds were assessed for parameter values: moisture content, germination, first count, accelerated aging (standard: 40 mL of water; saline solution: 11 g NaCl/100mL of water and saturated saline solution: 40 g NaCl/100mL water) and seedling emergence in soil. Accelerated aging through the use of saturated salt solution for 48 h or 72 h at 41°C resulted in an alternative and efficient way to evaluate the physiological quality of tomato seeds. The standard accelerated aging test was less efficient and exhibited higher moisture variation.
The relationship between apoptosis and aging
Apoptosis is involved in aging and age-related disease, with respect to aging, apoptosis acting in a celltype-specific manner. The rate of apoptosis is elevated in-most types of aging cell populations and organs. In stable cells and certain continuously dividing cells, apoptosisserves to eliminate presumably dysfunctional cellsthat show homeostatic failure due to oxidative stress, glycation, and DNA damage, thereby maintaining homeostasis in the body. What’smore, apoptosis, at least in part, plays some important role inthe regulation of aging process and anti-tumorigenesis in mammals. Age-enhanced apoptosis may be aninnateprotective mechanism against age-associated tumorigenesis. There is clear evidence to indicate that senescentcells are remarkably resistant to apoptosis. The intensity of global apoptosis and autophagy clearance significantly declines in humans during aging, as aging repress the apoptotic response. In this paper, we will review the relationship between apoptosis and aging, and outline how are they interact each other. see also: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=23667
9/16/2014
Aging and the decline in health
Author(s) ：Robin Holliday
The biological reasons for aging are now understood. Aging is the result of multiple stochastic events in molecules, cells, tissues and organs. These together produce the aged phenotype, senescence and ultimately death. Many of these changes can be directly linked to specific age-associated disease. However, there are also age-related changes that are not pathological. It can be said that aging has multiple causes, or is instead due to a general loss of molecular fidelity, that is, an increase in disorder. The complexity of organism means that they develop as ordered structures by obtaining energy from the environment. These ordered structures must be maintained by a wide variety of mechanisms which also depend on energy resources. Eventually these mechanisms fail, and senescence sets in. It is known that the efficiency of maintenance is correlated directly with the lifespan of different mammalian species. Also, these lifespans are inversely correlated with fecundity or reproductive potential. There is a trade off between investment of resources in maintenance of the body, or soma, and investment in reproduction.
The Sirtuins in Aging and Metabolic Regulation
Numerous theories of how and why aging occurs have been postulated but a definitive comprehensive explanation remains elusive. Attempts to unravel genetic details of aging resulted in the identification of a yeast gene known as Sir2 as a modulator of life span. Identification and characterization of mammalian Sir2 homologs followed and has catapulted aging research to exciting new levels. This review begins with basic definitions of aging and then describes some of the most common theories of the aging process. The review presents information related to the initial discovery of the Sirtuins and summarizes some of the recent advances in defining roles for Sirtuin family members. SIRT6 is discussed in greater detail because it is one of the best characterized of the mammalian Sirtuins and seems to be one of the most important in the aging process and metabolic regulation.
9/15/2014
The Effect of Notch Filter on RFI Suppression
Radio Frequency Interference (RFI) suppression is an important technique in the ultra-wideband synthetic aperture radar (UWB SAR). In this paper, we mainly analyze the performance of a notch filter for RFI sup-pression. The theoretical output from notch filter is presented based on RFI signal’s narrowband property. The research conclusion shows that the notch filter has significant effect on sidelobes of the system response, which might be considered to be false targets, however it has little effect on the resolution of the system re-sponse. The theoretical result is verified by simulation and experimental data processing both in one dimen-sion (range dimension) and in two dimensions (range and azimuth dimension).
Phosphoinositide and phospholipid phosphorylation and hydrolysis pathways —Organophosphate and organochlorine pesticides effects
Phospholipid and phosphoinositide phosphorylation pathways have been shown to be of crucial importance on producing lipid mediators. The earlier findings reported on lipid molecules playing roles in different metabolic pathways used to assign them the exclusive role of second messenger generators. Several researchers have recently described how direct interaction of phospholipids and phosphoinositides with molecules or organelles, without the need for producing second messenger molecules, is responsible for their mechanism of action. Organophosphate and organochlorine pesticide toxicity mechanisms have been extensively studied in relation to their well known effects on cholinesterase activities and on the alterations of electric activity in the nervous system of different organisms respectively. There is little but consistent evidence that some compounds, including in both groups of pesticides, are also able to interact with phospholipid and phosphoinositide phosphorylation pathways in several organisms and tissues. The present review consists of an actualization of basic research on phospholipid and phosphoinositide phosphorylation and hydrolysis pathways, as well as a description of some reported evidences for the effects of the above mentioned pesticides on them
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Early Repair of Sternal Instability Prevents Mediastinitis
Author(s): Koray Aykut, Gokhan Albayrak, Aycan Kavala, Mehmet Guzeloglu, Kemal Karaarslan, Eyup Hazan
Background: Discharge due to superficial wound infection and sternal dehiscence are the common complications of median sternotomy. This condition leads to mediastinitis. Mediastinitis is a serious condition which increases morbidity, mortality and hospital costs. The correct time for surgical treatment is contraversial in cases who have sternal dehiscence and discharge due to superficial infection. In this study, patients received sternal stabilization as soon as a diagnosis was made and monitored for the development of mediastinitis. Methods: Among the 1440 patients who had undergone elective CABG, a total of 85 patients who developed sternal dehiscence and superficial wound discharge were included in this study. These patients were re-operated on as soon as diagnosed and early sternal stabilization was provided. Results: The ratio of overall dehiscence was 5.9%. Mediastinitis developed in only 2 of the 85 patients. These patients were treated with VAC (Vacuum Assisted Closure) therapy. The ratio of overall mediastinitis was 0.13. Mediastinitis-related mortality was not detected. Conclusion: The ratio of mediastinitis decreases when patients who have discharge due to sternal dehiscence and superficial wound infection are immediately reviewed without waiting for the results of conventional methods such as antibiotic treatment and chest binder support
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Impact of high-fat diet on antioxidant status, vascular wall thickening and cardiac function in adult female LDLR–/– mice
Background: Western diet, rich in saturated fatty acids and cholesterol, is associated with increased cardiovascular risk. We thus investigated in female mice the influence of this diet on plasma antioxidant status, vascular wall thickening and cardiac function. Methods and Results: Adult female C57BL/6J wild type (WT) and LDLR–/– mice were fed a normal diet (ND) or a high-fat diet (HFD) for 17 weeks. HFD induced an increase in plasma lipids and vitamin C (Vit C) levels in both groups but at a much higher level in LDLR–/– and a decrease in plasma ascorbyl free radical levels to Vit C ratio (an endogenous oxidative stress index) in LDLR–/–. We only found a slight decrease in circulating antioxidant status evaluated by the Oxygen Radical Absorbance Capacity (ORAC) assay in WT, but not in LDLR–/–. Echocardiography evidenced an increase in arterial wall thickness in aortic arch at atherosclerosis predilection sites in HFD LDLR–/– as compared to ND LDLR–/– and HFD WT. This result was confirmed by histology. Further-more, histological examination of aortic valves showed an increase in atherosclerotic lesions. Our study, using echocardiography, show that chronic HFD does not induce any major modifications of systolic function in the both mice groups. Conclusions: High-fat intake in mice causes serious disturbances in lipid plasma levels associated to variations of circulating antioxidant status due, at least in part, to an increase in Vit C. At this stage, atherosclerotic lesions, observed in aortic arch and valve, do not impair cardiac function in HFD-fed mice.
9/02/2014
Contribution of Estrogen to Sex Dimorphic Expression of Cardiac Natriuretic Peptide and Nitric Oxide Synthase Systems in ANP Gene-Disrupted Mice
Background: Sex dimorphism in the prevalence, onset, development and progression of cardiovascular disease (CVD) is well recognized, but the mechanisms whereby sex hormones are believed to confer cardioprotection are still not fully understood. Objective: This study more closely delineates the effect of 17β-Estradiol (E2) on the expression and signaling of the cardiac NP and NOS systems, well-known cardioprotective modulators of the cardiac hypertrophy (CH) response, that both contribute to downstream production of cyclic guanosine 3’,5’-monophosphate (cGMP). Materials and Methods: Ovariectomized (OVX) female ANP+/+ and ANP-/- mice, 6 -7 weeks old, were subjected to a five-week treatment with E2 (100 μg/100 μL/day) or vehicle (VEH). Left ventricle from these treatment groups, along with that from age-matched male ANP+/+ and ANP-/- mice was used to assess expression of these systems by real-time quantitative PCR (qPCR). Left ventricle tissue and plasma cGMP were measured by enzyme immunoassay to assess alterations in resultant downstream signaling.Results: NP system expression was unchanged across genotype, sex and E2 treatment. Sex-specific differences in NOS system expression were observed; female mice showed an increased expression of NOS system genes that were significantly elevated in all but one of the E2 treatment groups. Left ventricle tissue cGMP remained unchanged across genotype, sex and E2 treatment. Plasma cGMP levels were unchanged in ANP+/+ treatment groups. In ANP-/- treatment groups, plasma cGMP in the female OVX-E2 mice was significantly higher compared to male and female OVX-VEH mice. Conclusion: These findings demonstrate that in the absence of ANP, E2 upregulates cardiac NOS system expression to produce cGMP. This study confirms the importance of the cardiac NOS system in females; this particular system may be a promising future target for sex-specific treatments and therapies for CVD in women.
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