bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Study for Protein-Protein Docking Using Global Optimization and Empirical Potentials
Authors: Lee Kyoungrim
Published: December 2008

Protein-protein interactions are important for biochemical processes in biological systems. The 3D structure of the macromolecular complex resulting from the protein-protein association is a very useful source to understand its specific functions. This work focuses on computational study for protein-protein docking, where the individually crystallized structures of interacting proteins are treated as rigid, and the conformational space generated by the two interacting proteins is explored extensively. The energy function consists of intermolecular electrostatic potential, desolvation free energy represented by empirical contact potential, and simple repulsive energy terms. The conformational space is six dimensional, represented by translational vectors and rotational angles formed between two interacting proteins. The conformational sampling is carried out by the search algorithms such as simulated annealing (SA), conformational space annealing (CSA), and CSA combined with SA simulations (combined CSA/SA). Benchmark tests are performed on a set of 18 protein-protein complexes selected from various protein families to examine feasibility of these search methods coupled with the energy function above for protein docking study.
A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures
Authors: Sahin Halil Turgut , Arslan Mustafa Burak
Published: December 2008

The cellulose paper treated in proportional mixture systems showed higher liquid absorption compare to only EtOH and MeOH treatments. It was approximately 40-70% and 50-91% higher for EtOH-NaOH and MeOH-NaOH treated papers, respectively. All conditions apparently bring about an effect of decreased strength for papers. The lowest tensile strength of 13.0 N/mm was found with EtOH and NaOH treated samples after 5th repeating wetting-drying stage. But, some conditions gave approximately 21-59.5% higher stretch than untreated samples. The pore size distributions of papers were evaluated with Simons stain procedure and experimental results usually consisted with sorption data. The less intense CH2-CH2- vibrations (1450-1700 cm-1) and C-C and C-O-C peak areas in FTIR spectra indicates lowering H-bonds in solvent treated and dried paper network structure.
Synthesis and Characterization of Molecularly Imprinted Polymers for Phenoxyacetic Acids
Authors: Zhang Huiting , Song Tao , Zong Fulin , Chen Tiechun , Pan Canping
Published: December 2008

2-methylphenoxyacetic acid (2-MPA), 2-methyl-4-chlorophenxyacetic acid (MCPA) and 4-chlorophenoxyacetic acid (4-CPA) were imprinted to investigate the cross-selectivities of molecularly imprinted polymers (MIPs). The result indicates that 2-MPA, which is similar in shape, size and functionality with phenoxyacetic herbicides, are suitable to be used as a suitable template to prepare the MIPs for retaining phenoxyacetic herbicides. To study the ion-pair interactions between template molecules and functional monomer 4-vinylpiridine (4-VP), computational molecular modeling was employed. The data indicate that the cross-selectivities of MIPs for phenoxyacetic acid herbicides depend on the binding energies of complexes.
Photodynamic Effect of Hypericin on the Conformation and Catalytic Activity of Hemoglobin
Authors: Zhao Jing , Meng Wenying , Miao Peng , Yu Zhiguo , Li Genxi
Published: December 2008

Hypericin, extracted from H. perforatum, can induce the generation of reactive oxygen species by visible light irradiation, which may consequently induce the conformational change of hemoglobin. We have not only employed UV-vis spectroscopy to observe the changes of UV-vis spectra of the protein, which reveals the conformational changes of the protein, but also employed electrochemical method to obtain its enhanced peroxidase activity. The photodynamic effect of hypericin on the conformation and catalytic activity of the protein has also been proven to be strongly dependent on the irradiation time, the hypericin concentration and the presence of oxygen. This work is beneficial not only to the fabrication of more sensitive hydrogen peroxide biosensor, but also to the guidance of the usage of this medicinal herb molecule, since the conformational change of the protein and the enhanced peroxidase can be easily obtained only by visible light irradiation on hypericin, the process of which is so common to happen.
Non-Edible Plant Oils as New Sources for Biodiesel Production
Authors: Chhetri Arjun B. , Tango Martin S. , Budge Suzanne M. , Watts K. Chris , Islam M. Rafiqul
Published: December 2008

Due to the concern on the availability of recoverable fossil fuel reserves and the environmental problems caused by the use those fossil fuels, considerable attention has been given to biodiesel production as an alternative to petrodiesel. However, as the biodiesel is produced from vegetable oils and animal fats, there are concerns that biodiesel feedstock may compete with food supply in the long-term. Hence, the recent focus is to find oil bearing plants that produce non-edible oils as the feedstock for biodiesel production. In this paper, two plant species, soapnut (Sapindus mukorossi) and jatropha (jatropha curcas, L.) are discussed as newer sources of oil for biodiesel production. Experimental analysis showed that both oils have great potential to be used as feedstock for biodiesel production. Fatty acid methyl ester (FAME) from cold pressed soapnut seed oil was envisaged as biodiesel source for the first time. Soapnut oil was found to have average of 9.1% free FA, 84.43% triglycerides, 4.88% sterol and 1.59% others. Jatropha oil contains approximately 14% free FA, approximately 5% higher than soapnut oil. Soapnut oil biodiesel contains approximately 85% unsaturated FA while jatropha oil biodiesel was found to have approximately 80% unsaturated FA. Oleic acid was found to be the dominant FA in both soapnut and jatropha biodiesel. Over 97% conversion to FAME was achieved for both soapnut and jatropha oil.
Synthesis and Characterization of Core-Shell Acrylate Based Latex and Study of Its Reactive Blends
Authors: Liu Xiang , Fan Xiao-Dong , Tang Min-Feng , Nie Ying
Published: December 2008

Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and glycidyl methacrylate (GMA) as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA) component as the core and P(EHA-co-GMA) component as the shell. Results of Transmission Electron Microscopy (TEM) and Dynamics Light Scattering (DLS) tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF) or urea-formaldehyde resin (UF). It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.
Anti-Cancer Effects of Xanthones from Pericarps of Mangosteen
Authors: Akao Yukihiro , Nakagawa Yoshihito , Nozawa Yoshinori
Published: December 2008

Mangosteen, Garcinia mangostana Linn, is a tree found in South East Asia, and its pericarps have been used as traditional medicine. Phytochemical studies have shown that they contain a variety of secondary metabolites, such as oxygenated and prenylated xanthones. Recent studies revealed that these xanthones exhibited a variety of biological activities containing anti-inflammatory, anti-bacterial, and anti-cancer effects. We previously investigated the anti-proliferative effects of four prenylated xanthones from the pericarps; α-mangostin, β-mangostin, γ-mangostin, and methoxy-β-mangostin in various human cancer cells. These xanthones are different in the number of hydroxyl and methoxy groups. Except for methoxy-β-mangostin, the other three xanthones strongly inhibited cell growth at low concentrations from 5 to 20 μM in human colon cancer DLD-1 cells. Our recent study focused on the mechanism of α-mangostin-induced growth inhibition in DLD-1 cells. It was shown that the anti-proliferative effects of the xanthones were associated with cell-cycle arrest by affecting the expression of cyclins, cdc2, and p27; G1 arrest by α- mangostin and β-mangostin, and S arrest by γ-mangostin. α-Mangostin found to induce apoptosis through the activation of intrinsic pathway following the down-regulation of signaling cascades involving MAP kinases and the serine/threonine kinase Akt. Synergistic effects by the combined treatment of α-mangostin and anti-cancer drug 5-FU was to be noted. α-Mangostin was found to have a cancer preventive effect in rat carcinogenesis bioassay and the extract from pericarps, which contains mainly α-mangostin and γ- mangostin, exhibited an enhancement of NK cell activity in a mouse model. These findings could provide a relevant basis for the development of xanthones as an agent for cancer prevention and the combination therapy with anti-cancer drugs.
Synthesis and Characterization of Polyacetylene with Side-chain Thiophene Functionality
Authors: Koz Banu , Kiskan Baris , Yagci Yusuf
Published: December 2008

A new polyacetylene derivative with electroactive thiophene substituent, namely poly(2-methylbut-2-enyl thiophene-3-carboxylate) was synthesized and characterized. For this purpose, novel acetylene monomer was synthesized by the reaction of 3- thiophenecarboxylic acid with propargyl bromide and polymerized with a Rh catalyst to give the corresponding polymer. The chemical structure of the polymer was characterized to comprise the conjugated backbone and electroactive thiophene side group. UV spectral changes of the polymer with temperature were also studied. The polymer exhibited better thermal stability than the unsubstituted polyacetylenes.
Supramolecular Layer-by-Layer Assembly of 3D Multicomponent Nanostructures via Multivalent Molecular Recognition
Authors: Ling Xing Yi , Phang In Yee , Reinhoudt David N. , Vancso G. Julius , Huskens Jurriaan
Published: December 2008

The supramolecular layer-by-layer assembly of 3D multicomponent nanostructures of nanoparticles is demonstrated. Nanoimprint lithography (NIL) was used as the patterning tool for making patterned β-cyclodextrin (CD) self-assembled monolayers (SAMs) and for the confinement of nanoparticles on the substrate. A densely packed and multilayered nanoparticle structure was created by alternating assembly steps of complementary guest- (Fc-SiO2, 60 nm) and host-functionalized (CD-Au, 3 nm) nanoparticles. The effects induced by the order of the nanoparticle assembly steps, going from large to small and from small to large nanoparticles by using Fc-SiO2, CD-Au, and CD-SiO2 (350 nm) nanoparticles, were compared. AFM height profiles revealed that the specific supramolecular assembly of nanoparticles was self-limited, i.e. one nanoparticle layer per assembly step, allowing the control over the thickness of the supramolecular hybrid nanostructure by choosing the size of the nanoparticles, irrespective of the core material of the nanoparticles. The roughness of structure, observed by AFM imaging of the top layer, was directly influenced by the size and packing of the underlying nanoparticle layers.
Combustion Analysis of Different Olive Residues
Authors: Miranda Teresa , Esteban Alberto , Rojas Sebastián , Montero Irene , Ruiz Antonio
Published: December 2008

The Thermogravimetric Analysis (TGA) techniques and concretely the study of the burning profile provide information that can be used to estimate the behaviour of the combustion of carbonous materials. Commonly, these techniques have been used for the study of carbons, but are also interesting for the analysis of biomass wastes, due to the different species present on the wastes affect directly to its thermal properties. In this work, techniques of thermal analysis have been applied to compare the behaviour of different wastes coming from olive oil mills. From these results, it is remarkable that the Concentrated Olive Mill Waste Water (COMWW) presents more unfavourable conditions for its combustion.
Identification of Select Fumonisin Forming Fusarium Species Using PCR Applications of the Polyketide Synthase Gene and its Relationship to Fumonisin Production in vitro
Authors: Baird Richard , Abbas Hamed K. , Windham Gary , Williams Paul , Baird Sonya , Ma Peter , Kelley Rowena , Hawkins Leigh , Scruggs Mary
Published: December 2008

A polymerase chain reaction (PCR) based diagnostic assay was used to develop markers for detection of Fusarium verticillioides (=F. moniliforme), a fumonisin producing fungus in maize tissues. Species-specific primers were designed based on sequence data from the polyketide synthase (PKS) gene (FUM1- previously FUM5) responsible for fumonisin production in fungi. Four sets of oligonucleotide primers were tested for their specificity using 24 strains of F. verticillioides, 10 F. proliferatum, and 12 of other Fusarium species. In addition, 13 species of other fungal genera, from four phyla, were tested as negative controls. Among the four sets, primer set B consistently amplified a 419- bp fragment from the DNA 96% of all F. verticillioides strains and 83% of F. proliferatum. All other fungi tested were negative using primer set B. A total of 38% of the F. verticillioides strains grown on a selective liquid medium produced fumonisin and 92% formed the toxin on standard rice medium. When fumonisin formed in culture, PCR assay using primer set B detected every strain of F. verticillioides, but only amplified 80% of F. proliferatum strains that produced the toxin. PCR detection was consistent at 100 pg/μl concentration of genomic DNA from 4 F. verticillioides strains, but varied at 10 pg/μl. Two duplicate greenhouse tests using artificially inoculated maize plants, had greater levels of F. verticillioides detected after re-evaluting using primer set B than from culturing of the tissues. The molecular protocols described in this study requires only 1 day for completion compared to approximately 10 days for cultural work and morphological determination. In conclusion, conventional PCR assay using primer set B provides a sensitive and accurate detection assay that can be used as a primary or secondary confirmation method for identification and occurrence of F. verticillioides within the maize tissues. However, studies using primer set B for fumonisin production determined by strains of F. verticillioides and F. proliferatum will require further verification.
Specific siRNA Targeting the Receptor for Advanced Glycation End Products Inhibits Experimental Hepatic Fibrosis in Rats
Authors: Xia Jin-Rong , Liu Nai-Feng , Zhu Nai-Xun
Published: December 2008

Receptor for advanced glycation end products (RAGE) was studied in different stages of carbon tetrachloride induced hepatic fibrosis (HF), and effect of its gene silencing in the HF development was evaluated in rats. Silencing RAGE expression by specific siRNA effectively suppressed NF-κB activity, hepatic stellate cell activation, and accumulation of extracellular matrix proteins in the fibrotic liver, and also greatly improved the histopathology and the ultra-structure of liver cells. These effects may be partially mediated by the inhibition on IκBα degradation. RAGE gene silencing effectively prevented liver from fibrosis, therefore it offers a potential pharmacological tool for anti-HF gene therapy.
CELL-SELEX: Novel Perspectives of Aptamer-Based Therapeutics
Authors: Guo Ke-Tai , Ziemer Gerhard , Paul Angela , Wendel Hans P.
Published: December 2008

Aptamers, single stranded DNA or RNA molecules, generated by a method called SELEX (systematic evolution of ligands by exponential enrichment) have been widely used in various biomedical applications. The newly developed Cell-SELEX (cell based-SELEX) targeting whole living cells has raised great expectations for cancer biology, -therapy and regenerative medicine. Combining nanobiotechnology with aptamers, this technology opens the way to more sophisticated applications in molecular diagnosis. This paper gives a review of recent developments in SELEX technologies and new applications of aptamers.
Azaspiracid Shellfish Poisoning: A Review on the Chemistry, Ecology, and Toxicology with an Emphasis on Human Health Impacts
Authors: Twiner Michael J. , Rehmann Nils , Hess Philipp , Doucette Gregory J.
Published: December 2008

Azaspiracids (AZA) are polyether marine toxins that accumulate in various shellfish species and have been associated with severe gastrointestinal human intoxications since 1995. This toxin class has since been reported from several countries, including Morocco and much of western Europe. A regulatory limit of 160 μg AZA/kg whole shellfish flesh was established by the EU in order to protect human health; however, in some cases, AZA concentrations far exceed the action level. Herein we discuss recent advances on the chemistry of various AZA analogs, review the ecology of AZAs, including the putative progenitor algal species, collectively interpret the in vitro and in vivo data on the toxicology of AZAs relating to human health issues, and outline the European legislature associated with AZAs.
Mycosporine-Like Amino Acids and Marine Toxins - The Common and the Different
Authors: Klisch Manfred , Häder Donat P.
Published: December 2008

Marine microorganisms harbor a multitude of secondary metabolites. Among these are toxins of different chemical classes as well as the UV-protective mycosporinelike amino acids (MAAs). The latter form a group of water-soluble, low molecular-weight (generally < 400) compounds composed of either an aminocyclohexenone or an aminocyclohexenimine ring, carrying amino acid or amino alcohol substituents. So far there has been no report of toxicity in MAAs but nevertheless there are some features they have in common with marine toxins. Among the organisms producing MAAs are cyanobacteria, dinoflagellates and diatoms that also synthesize toxins. As in cyclic peptide toxins found in cyanobacteria, amino acids are the main building blocks of MAAs. Both, MAAs and some marine toxins are transferred to other organisms e.g. via the food chains, and chemical modifications can take place in secondary consumers. In contrast to algal toxins, the physiological role of MAAs is clearly the protection from harmful UV radiation by physical screening. However, other roles, e.g. as osmolytes and antioxidants, are also considered. In this paper the common characteristics of MAAs and marine toxins are discussed as well as the differences.
Diverse Bacterial PKS Sequences Derived From Okadaic Acid-Producing Dinoflagellates
Authors: Perez Roberto , Liu Li , Lopez Jose , An Tianying , Rein Kathleen S.
Published: December 2008

Okadaic acid (OA) and the related dinophysistoxins are isolated from dinoflagellates of the genus Prorocentrum and Dinophysis. Bacteria of the Roseobacter group have been associated with okadaic acid producing dinoflagellates and have been previously implicated in OA production. Analysis of 16S rRNA libraries reveals that Roseobacter are the most abundant bacteria associated with OA producing dinoflagellates of the genus Prorocentrum and are not found in association with non-toxic dinoflagellates. While some polyketide synthase (PKS) genes form a highly supported Prorocentrum clade, most appear to be bacterial, but unrelated to Roseobacter or Alpha-Proteobacterial PKSs or those derived from other Alveolates Karenia brevis or Crytosporidium parvum.
Domoic Acid Toxicologic Pathology: A Review
Authors: Pulido Olga M.
Published: December 2008

Domoic acid was identified as the toxin responsible for an outbreak of human poisoning that occurred in Canada in 1987 following consumption of contaminated blue mussels [Mytilus edulis]. The poisoning was characterized by a constellation of clinical symptoms and signs. Among the most prominent features described was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Domoic acid is produced by certain marine organisms, such as the red alga Chondria armata and planktonic diatom of the genus Pseudo-nitzschia. Since 1987, monitoring programs have been successful in preventing other human incidents of ASP. However, there are documented cases of domoic acid intoxication in wild animals and outbreaks of coastal water contamination in many regions world-wide. Hence domoic acid continues to pose a global risk to the health and safety of humans and wildlife. Several mechanisms have been implicated as mediators for the effects of domoic acid. Of particular importance is the role played by glutamate receptors as mediators of excitatory neurotransmission and the demonstration of a wide distribution of these receptors outside the central nervous system, prompting the attention to other tissues as potential target sites. The aim of this document is to provide a comprehensive review of ASP, DOM induced pathology including ultrastructural changes associated to subchronic oral exposure, and discussion of key proposed mechanisms of cell/tissue injury involved in DOM induced brain pathology and considerations relevant to food safety and human health.
Recreational Exposure to Low Concentrations of Microcystins During an Algal Bloom in a Small Lake
Authors: Backer Lorraine C. , Carmichael Wayne , Kirkpatrick Barbara , Williams Christopher , Irvin Mitch , Zhou Yue , Johnson Trisha B. , Nierenberg Kate , Hill Vincent R. , Kieszak Stephanie M. , Cheng Yung-Sung
Published: December 2008

We measured microcystins in blood from people at risk for swallowing water or inhaling spray while swimming, water skiing, jet skiing, or boating during an algal bloom. We monitored water samples from a small lake as a Microcystis aeruginosa bloom developed. We recruited 97 people planning recreational activities in that lake and seven others who volunteered to recreate in a nearby bloom-free lake. We conducted our field study within a week of finding a 10-μg/L microcystin concentration. We analyzed water, air, and human blood samples for water quality, potential human pathogens, algal taxonomy, and microcystin concentrations. We interviewed study participants for demographic and current health symptom information. Water samples were assayed for potential respiratory viruses (adenoviruses and enteroviruses), but none were detected. We did find low concentrations of Escherichia coli, indicating fecal contamination. We found low levels of microcystins (2 μg/L to 5 μg/L) in the water and (
Floridoside Extracted from the Red Alga Mastocarpus stellatus Is a Potent Activator of the Classical Complement Pathway
Authors: Courtois Anthony , Simon-Colin Christelle , Boisset Claire , Berthou Christian , Deslandes Eric , Guézennec Jean , Bordron Anne
Published: December 2008

Many biological properties of algae have been found to have useful applications in human health, particularly in the fields of oncology and immunology. Floridoside, extracted from the red alga Mastocarpus stellatus, has a structure similar to the xenoantigen Gal alpha 1-3 Gal. This xenoantigen has been described to induce a high immune response in human xenografts and is mediated by natural anti-gal antibodies that activate the classical complement pathway. Based on this property, we analyzed the potential activities of floridoside on the immune system. We demonstrated that floridoside activates a complement cascade via the classical complement pathway, through the recruitment and activation of natural IgM. This algal molecule could represent an important step in the development of a potent new anticomplementary agent for use in therapeutic complement depletion.
Neurotoxic Shellfish Poisoning
Authors: Watkins Sharon M. , Reich Andrew , Fleming Lora E. , Hammond Roberta
Published: December 2008

Neurotoxic shellfish poisoning (NSP) is caused by consumption of molluscan shellfish contaminated with brevetoxins primarily produced by the dinoflagellate, Karenia brevis. Blooms of K. brevis, called Florida red tide, occur frequently along the Gulf of Mexico. Many shellfish beds in the US (and other nations) are routinely monitored for presence of K. brevis and other brevetoxin-producing organisms. As a result, few NSP cases are reported annually from the US. However, infrequent larger outbreaks do occur. Cases are usually associated with recreationally-harvested shellfish collected during or post red tide blooms. Brevetoxins are neurotoxins which activate voltage-sensitive sodium channels causing sodium influx and nerve membrane depolarization. No fatalities have been reported, but hospitalizations occur. NSP involves a cluster of gastrointestinal and neurological symptoms: nausea and vomiting, paresthesias of the mouth, lips and tongue as well as distal paresthesias, ataxia, slurred speech and dizziness. Neurological symptoms can progress to partial paralysis; respiratory distress has been recorded. Recent research has implicated new species of harmful algal bloom organisms which produce brevetoxins, identified additional marine species which accumulate brevetoxins, and has provided additional information on the toxicity and analysis of brevetoxins. A review of the known epidemiology and recommendations for improved NSP prevention are presented.
Smenospongine, a Sesquiterpene Aminoquinone from a Marine Sponge, Induces G1 Arrest or Apoptosis in Different Leukemia Cells
Authors: Kong Dexin , Aoki Shunji , Sowa Yoshihiro , Sakai Toshiyuki , Kobayashi Motomasa
Published: December 2008

Smenospongine, a sesquiterpene aminoquinone isolated from the marine sponge Dactylospongia elegans, was previously reported by us to induce erythroid differentiation and G1 phase arrest of K562 chronic myelogenous leukemia cells. In this study, we investigated the effect of smenospongine on the cell cycles of other leukemia cells, including HL60 human acute promyelocytic leukemia cells and U937 human histiocytic lymphoma cells by flow cytometric analysis. Smenospongine induced apoptosis dosedependently in HL60 and U937 cells. The smenospongine treatment increased expression of p21 and inhibited phosphorylation of Rb in K562 cells, suggesting the p21-Rb pathway play an important role in G1 arrest in K562 cells. However, the p21 promoter was not activated by the smenospongine treatment based on a luciferase assay using the transfected K562 cells. Smenospongine might induce p21 expression via another mechanism than transactivation of p21 promoter.
Characterization of Streptomyces spp. Isolated from the Sea Surface Microlayer in the Trondheim Fjord, Norway
Authors: Hakvåg Sigrid , Fjærvik Espen , Josefsen Kjell D. , Ian Elena , Ellingsen Trond E. , Zotchev Sergey B.
Published: December 2008

The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of 217 isolates from two separate samples morphologically resembling the genus Streptomyces have been further investigated in this study. Antimicrobial assays showed that about 80% of the isolates exhibited antagonistic activity against nonfilamentous fungus, Gram-negative, and Gram-positive bacteria. Based on the macroscopic analyses and inhibition patterns from the antimicrobial assays, the sub-grouping of isolates was performed. Partial 16S rDNAs from the candidates from each subgroup were sequenced and phylogenetic analysis performed. 7 isolates with identical 16S rDNA sequences were further studied for the presence of PKS type I genes. Sequencing and phylogenetic analysis of the PKS gene fragments revealed that horizontal gene transfer between closely related species might have taken place. Identification of unique PKS genes in these isolates implies that dereplication can not be performed based solely on the 16S rDNA sequences. The results obtained in this study suggest that streptomycetes from the neuston population may be an interesting source for discovery of new antimicrobial agents.
Wavelength Dependence of Photoinduced Microcantilever Bending in the UV-VIS Range
Authors: Steinbock Lorenz J. , Helm Mark
Published: December 2008

Micromechanical devices such as microcantilevers (MC) respond to irradiationwith light by at least two different, photon-mediated processes, which induce MC bendingas a consequence of differential surface stress. The first and slow bending is due to theabsorption of photons, whose energy is transformed into heat and causes bending ofbimetallic microcantilevers due to thermal expansion. The second type of deflection is fastand caused by photons of sufficient energy to promote electrons across the Schottky barrierand thus create charge carriers, resulting in photoinduced stress that causes MC bending. Inthis study, the MC bending response to irradiation with light of wavelengths ranging from250 to 700 nm was investigated. Measurements of the immediate mechanical response tophotoinduced stress as a function of the wavelength of incident light provide an avenue tothe determination of the cut-off wavelength/energy of the Schottky barrier in the MCdevices under investigation. For a gold coated Si3Ni4 microcantilever we measured a cutoffwavelength of 1206 nm, which lies in the range of the literature value of 1100 nm.
Assessment of Evapotranspiration and Soil Moisture Content Across Different Scales of Observation
Authors: Verstraeten Willem W. , Veroustraete Frank , Feyen Jan
Published: December 2008

The proper assessment of evapotranspiration and soil moisture content arefundamental in food security research, land management, pollution detection, nutrient flows,(wild-) fire detection, (desert) locust, carbon balance as well as hydrological modelling; etc.This paper takes an extensive, though not exhaustive sample of international scientificliterature to discuss different approaches to estimate land surface and ecosystem relatedevapotranspiration and soil moisture content. This review presents:(i) a summary of the generally accepted cohesion theory of plant water uptake andtransport including a shortlist of meteorological and plant factors influencing planttranspiration;(ii) a summary on evapotranspiration assessment at different scales of observation (sapflow,porometer, lysimeter, field and catchment water balance, Bowen ratio,scintillometer, eddy correlation, Penman-Monteith and related approaches);(iii) a summary on data assimilation schemes conceived to estimate evapotranspirationusing optical and thermal remote sensing; and(iv) for soil moisture content, a summary on soil moisture retrieval techniques atdifferent spatial and temporal scales is presented.Concluding remarks on the best available approaches to assess evapotranspiration and soilmoisture content with and emphasis on remote sensing data assimilation, are provided.
Electronic Nose Based on Metal Oxide Semiconductor Sensors as an Alternative Technique for the Spoilage Classification of Red Meat
Authors: El Barbri Noureddine , Llobet Eduard , El Bari Nezha , Correig Xavier , Bouchikhi Benachir
Published: December 2008

The aim of the present study was to develop an electronic nose for the quality control of red meat. Electronic nose and bacteriological measurements are performed to analyse samples of beef and sheep meat stored at 4°C for up to 15 days. Principal component analysis (PCA) and support vector machine (SVM) based classification techniques are used to investigate the performance of the electronic nose system in the spoilage classification of red meats. The bacteriological method was selected as the reference method to consistently train the electronic nose system. The SVM models built classified meat samples based on the total microbial population into “unspoiled” (microbial counts < 6 log10 cfu/g) and “spoiled” (microbial counts ≥ 6 log10 cfu/g). The preliminary results obtained by the bacteria total viable counts (TVC) show that the shelf-life of beef and sheep meats stored at 4 °C are 7 and 5 days, respectively. The electronic nose system coupled to SVM could discriminate between unspoiled/ spoiled beef or sheep meats with a success rate of 98.81 or 96.43 %, respectively. To investigate whether the results of the electronic nose correlated well with the results of the bacteriological analysis, partial least squares (PLS) calibration models were built and validated. Good correlation coefficients between the electronic nose signals and bacteriological data were obtained, a clear indication that the electronic nose system can become a simple and rapid technique for the quality control of red meats.
Lightning Sensors for Observing, Tracking and Nowcasting Severe Weather
Authors: Price Colin
Published: December 2008

Severe and extreme weather is a major natural hazard all over the world, oftenresulting in major natural disasters such as hail storms, tornados, wind storms, flash floods,forest fires and lightning damages. While precipitation, wind, hail, tornados, turbulence,etc. can only be observed at close distances, lightning activity in these damaging stormscan be monitored at all spatial scales, from local (using very high frequency [VHF]sensors), to regional (using very low frequency [VLF] sensors), and even global scales(using extremely low frequency [ELF] sensors). Using sensors that detect the radio wavesemitted by each lightning discharge, it is now possible to observe and track continuouslydistant thunderstorms using ground networks of sensors. In addition to the number oflightning discharges, these sensors can also provide information on lightningcharacteristics such as the ratio between intra-cloud and cloud-to-ground lightning, thepolarity of the lightning discharge, peak currents, charge removal, etc. It has been shownthat changes in some of these lightning characteristics during thunderstorms are oftenrelated to changes in the severity of the storms. In this paper different lightning observingsystems are described, and a few examples are provided showing how lightning may beused to monitor storm hazards around the globe, while also providing the possibility ofsupplying short term forecasts, called nowcasting.
Chemical Sensing Sensitivity of Long-Period Grating Sensor Enhanced by Colloidal Gold Nanoparticles
Authors: Tang Jaw-Luen , Wang Jien-Neng
Published: December 2008

A simple and effective method is proposed to improve spectral sensitivity anddetection limit of long period gratings for refractive index or chemical sensing, where thegrating surface is modified by a monolayer of colloidal gold nanoparticles. Thetransmission spectra and optical properties of gold nanospheres vary with the differentrefractive index of the environment near the surface of gold nanospheres. The sensorresponse of gold colloids increases linearly with solvents of increasing refractive index.The results for the measurement of sucrose and sodium chloride solutions are reported,which show that this type of sensor can provide a limiting resolution of ~10-3 to ~10-4 forrefractive indices in the range of 1.34 to 1.39 and a noticeable increase in detection limit ofrefractive index to external medium.
Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications
Authors: Kim Dong-Woo , Cho Myeong-Woo , Seo Tae-Il , Shin Young-Jae
Published: December 2008

Recently, the magnetorheological (MR) polishing process has been examined asa new ultra-precision polishing technology for micro parts in MEMS applications. In theMR polishing process, the magnetic force plays a dominant role. This method uses MRfluids which contains micro abrasives as a polishing media. The objective of the presentresearch is to shed light onto the material removal mechanism under various slurryconditions for polishing and to investigate surface characteristics, including shape analysisand surface roughness measurement, of spots obtained from the MR polishing process usingalumina abrasives. A series of basic experiments were first performed to determine theoptimum polishing conditions for BK7 glass using prepared slurries by changing the processparameters, such as wheel rotating speed and electric current. Using the obtained results,groove polishing was then performed and the results are investigated. Outstanding surfaceroughness of Ra=3.8nm was obtained on the BK7 glass specimen. The present resultshighlight the possibility of applying this polishing method to ultra-precision micro partsproduction, especially in MEMS applications.
Advances in Remote Sensing for Oil Spill Disaster Management: State-of-the-Art Sensors Technology for Oil Spill Surveillance
Authors: Jha Maya Nand , Levy Jason , Gao Yang
Published: December 2008

Reducing the risk of oil spill disasters is essential for protecting the environmentand reducing economic losses. Oil spill surveillance constitutes an important component ofoil spill disaster management. Advances in remote sensing technologies can help to identifyparties potentially responsible for pollution and to identify minor spills before they causewidespread damage. Due to the large number of sensors currently available for oil spillsurveillance, there is a need for a comprehensive overview and comparison of existingsensors. Specifically, this paper examines the characteristics and applications of differentsensors. A better understanding of the strengths and weaknesses of oil spill surveillancesensors will improve the operational use of these sensors for oil spill response andcontingency planning. Laser fluorosensors were found to be the best available sensor for oilspill detection since they not only detect and classify oil on all surfaces but also operate ineither the day or night. For example, the Scanning Laser Environmental AirborneFluorosensor (SLEAF) sensor was identified to be a valuable tool for oil spill surveillance.However, no single sensor was able to provide all information required for oil spillcontingency planning. Hence, combinations of sensors are currently used for oil spillsurveillance. Specifically, satellite sensors are used for preliminary oil spill assessmentwhile airborne sensors are used for detailed oil spill analysis. While satellite remote sensingis not suitable for tactical oil spill planning it can provide a synoptic coverage of theaffected area.
A Review on the Electrochemical Sensors and Biosensors Composed of Nanowires as Sensing Material
Authors: Yogeswaran Umasankar , Chen Shen-Ming
Published: December 2008

The development and application of nanowires for electrochemical sensors and biosensors are reviewed in this article. Next generation sensor platforms will require significant improvements in sensitivity, specificity and parallelism in order to meet the future needs in variety of fields. Sensors made of nanowires exploit some fundamental nanoscopic effect in order to meet these requirements. Nanowires are new materials, which have the characteristic of low weight with extraordinary mechanical, electrical, thermal and multifunctional properties. The advantages such as size scale, aspect ratio and other properties of nanowires are especially apparent in the use of electrical sensors such as electrochemical sensors and in the use of field-effect transistors. The preparation methods of nanowires and their properties are discussed along with their advantages towards electrochemical sensors and biosensors. Some key results from each article are summarized, relating the concept and mechanism behind each sensor, with experimental conditions as well as their behavior at different conditions.
Sensitivity of PZT Impedance Sensors for Damage Detection of Concrete Structures
Authors: Yang Yaowen , Hu Yuhang , Lu Yong
Published: December 2008

Piezoelectric ceramic Lead Zirconate Titanate (PZT) based electro-mechanicalimpedance (EMI) technique for structural health monitoring (SHM) has been successfullyapplied to various engineering systems. However, fundamental research work on thesensitivity of the PZT impedance sensors for damage detection is still in need. In thetraditional EMI method, the PZT electro-mechanical (EM) admittance (inverse of theimpedance) is used as damage indicator, which is difficult to specify the effect of damage onstructural properties. This paper uses the structural mechanical impedance (SMI) extractedfrom the PZT EM admittance signature as the damage indicator. A comparison study on thesensitivity of the EM admittance and the structural mechanical impedance to the damages ina concrete structure is conducted. Results show that the SMI is more sensitive to the damagethan the EM admittance thus a better indicator for damage detection. Furthermore, this paperproposes a dynamic system consisting of a number of single-degree-of-freedom elementswith mass, spring and damper components to model the SMI. A genetic algorithm isemployed to search for the optimal value of the unknown parameters in the dynamic system.An experiment is carried out on a two-storey concrete frame subjected to base vibrations thatsimulate earthquake. A number of PZT sensors are regularly arrayed and bonded to the framestructure to acquire PZT EM admittance signatures. The relationship between the damageindex and the distance of the PZT sensor from the damage is studied. Consequently, thesensitivity of the PZT sensors is discussed and their sensing region in concrete is derived.
Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites
Authors: Mengeloglu Fatih , Karakus Kadir
Published: December 2008

Thermal behaviors of wheat straw flour (WF) filled thermoplastic compositeswere measured applying the thermogravimetric analysis and differential scanningcalorimetry. Morphology and mechanical properties were also studied using scanningelectron microscope and universal testing machine, respectively. Presence of WF inthermoplastic matrix reduced the degradation temperature of the composites. One for WFand one for thermoplastics, two main decomposition peaks were observed. Morphologicalstudy showed that addition of coupling agent improved the compatibility between WFs andthermoplastic. WFs were embedded into the thermoplastic matrix indicating improvedadhesion. However, the bonding was not perfect because some debonding can also be seenon the interface of WFs and thermoplastic matrix. In the case of mechanical properties ofWF filled recycled thermoplastic, HDPE and PP based composites provided similar tensileand flexural properties. The addition of coupling agents improved the properties ofthermoplastic composites. MAPE coupling agents performed better in HDPE while MAPPcoupling agents were superior in PP based composites. The composites produced with thecombination of 50-percent mixture of recycled HDPE and PP performed similar with theuse of both coupling agents. All produced composites provided flexural properties requiredby the ASTM standard for polyolefin-based plastic lumber decking boards.
Using Monoclonal Antibody to Determine Lead Ions with a Localized Surface Plasmon Resonance Fiber-optic Biosensor
Authors: Lin Tsao-Jen , Chung Mon-Fu
Published: December 2008

A novel reflection-based localized surface plasmon resonance (LSPR) fiber-optic probe has been developed to determine the heavy metal lead ion concentration. Monoclonal antibody as the detecting probe containing massive amino groups to capture Pb(II)-chelate complexes was immobilized onto gold nanoparticle-modified optical fiber (NMAuOF). The optimal immobilizing conditions of monoclonal antibody on to the NMAuOF are 189 μg/mL in pH7.4 PBS for 2 h at 25°C. The absorbability of the functionalized NMAuOF sensor increases to 12.2 % upon changing the Pb(II)-EDTA level from 10 to 100 ppb with a detection limit of 0.27 ppb. The sensor retains 92.7 % of its original activity and gives reproducible results after storage in 5% D-( )-Trehalose dehydrate solution at 4°C for 35 days. In conclusion, the monoclonal antibody-functionalized NMAuOF sensor shows a promising result for determining the concentration of Pb(II) with high sensitivity.
Using Geospatial Information Technology in Natural Resources Management: The Case of Urban Land Management In West Africa
Authors: Merem Edmund C. , Twumasi Yaw A.
Published: December 2008

In the past several decades, Lagos Metropolis emerged as one of the fastesturbanizing cities in the West African Sub-region. In the absence of a regular use ofgeospatial information management systems, limited effort had been made to keep track ofchanges in the natural environment in the rapidly growing city for policy making in landadministration. The ubiquitous energy radiated by the rapid urbanization rate in the areanot only created unprecedented consequences by diminishing the quality of theenvironment and natural resources but it raises serious implications for land managementin the region. The factors fuelling the land crisis in the area which are not far fetchedconsists of socio-economic, ecological and policy elements. To tackle these issues in amega city, up-to-date knowledge would be required to capture and analyze landinformation trends. Such an effort will help manage the city’s expansion as well asinfrastructure development through the right choices in planning and (spatial) designsusing the latest tools in geospatial technologies of Geographic Information Systems GIS)and remote sensing. This study investigates the spatial implications of the rapid expansionof metropolitan Lagos for land management using GIS and Remote sensing technology.The result of the research provides a valuable road map that can enable planners contributeto improved land administration necessary for effective management of natural resources.