bluuebunny/crossref_metadata_2025 huggingface dataset:
The Y chromosome-specific STS marker MS2 and its peripheral regions on the Y chromosome of the dioecious plantSilene latifolia
Authors: Ishii Kotaro , Sugiyama Ryuji , Onuki Megumi , Kazama Yusuke , Sachihiro Matsunaga  , Kawano Shigeyuki
Published: April 2008

Sex determination in Silene latifolia uses the XX/XY system. The recent evolution of dioecy in S. latifolia provides a unique opportunity to study the early stages of Y chromosome evolution. However, the current Y chromosome map still contains many large gaps with no available markers. In this study, a sequence tagged site (STS) marker, MS2, was isolated and mapped to the same locus as L8 on the Y chromosome. To investigate the peripheral regions of MS2, a bacterial artificial chromosome (BAC) library was constructed from a male plant, and the BAC clone containing MS2 (MS2-9d12F) was isolated from 32 640 clones with an average insert size of 115 kb. A 109-kb insert of the BAC clone was analyzed. BLASTX analysis showed 11 sequences similar to some known proteins, most of which are retrotransposon-like elements. The ORF Finder predicted 9 ORFs within MS2-9d12F. RT-PCR analyses revealed that only 4 of the 9 predicted ORFs are expressed in both male and female plants. These 4 ORFs are candidates for genes having counterparts on both the X and Y chromosomes. Dot-matrix plot analysis and a BLASTN search revealed LTR-like sequences close to the retrotransposon-like elements and high similarity to 3 known genomic sequences of S. latifolia. These results suggest an accumulation of retrotransposons and segmental duplications in peripheral regions of MS2 during the early stage of sex chromosome evolution.
Microsatellite discovery from BAC end sequences and genetic mapping to anchor the soybean physical and genetic maps
Authors: Shoemaker Randy C. , Grant David , Olson Terry , Warren Wesley C. , Wing Rod , Yu Yeisoo , Kim HyeRan , Cregan Perry , Joseph Bindu , Futrell-Griggs Montona , Will Nelson  , Davito Jon , Walker Jason , Wallis John , Kremitski Colin , Scheer Debbie , Clifton Sandra W. , Graves Tina , Nguyen Henry , Wu Xiaolei , Luo Mingcheng , Dvorak Jan , Nelson Rex , Cannon Steven , Tomkins Jeff , Schmutz Jeremy , Stacey Gary , Jackson Scott
Published: April 2008

Whole-genome sequencing of the soybean ( Glycine max (L.) Merr. ‘Williams 82’) has made it important to integrate its physical and genetic maps. To facilitate this integration of maps, we screened 3290 microsatellites (SSRs) identified from BAC end sequences of clones comprising the ‘Williams 82’ physical map. SSRs were screened against 3 mapping populations. We found the AAT and ACT motifs produced the greatest frequency of length polymorphisms, ranging from 17.2% to 32.3% and from 11.8% to 33.3%, respectively. Other useful motifs include the dinucleotide repeats AG, AT, and AG, with frequency of length polymorphisms ranging from 11.2% to 18.4% (AT), 12.4% to 20.6% (AG), and 11.3% to 16.4% (GT). Repeat lengths less than 16 bp were generally less useful than repeat lengths of 40–60 bp. Two hundred and sixty-five SSRs were genetically mapped in at least one population. Of the 265 mapped SSRs, 60 came from BAC singletons not yet placed into contigs of the physical map. One hundred and ten originated in BACs located in contigs for which no genetic map location was previously known. Ninety-five SSRs came from BACs within contigs for which one or more other BACs had already been mapped. For these fingerprinted contigs (FPC) a high percentage of the mapped markers showed inconsistent map locations. A strategy is introduced by which physical and genetic map inconsistencies can be resolved using the preliminary 4× assembly of the whole genome sequence of soybean.
Effects of organic compounds and recycling on ozone absorption in a portable water purification unit
Authors: Yao P. X. , Hendrawan F. B. , Bi H. T. , Wang J. H. , Fu J.
Published: April 2008

The absorption of ozone gas in a portable bubbling unit was investigated. First, six types of bubblers were tested under identical operating conditions with a gas flow rate of 1 L/min and a water volume of 1.5 L. A simple mass transfer model with the liquid phase assumed to be completely mixed and the axial ozone gas concentration gradient neglected was used to obtain the overall mass transfer coefficient, KLa, by fitting experimental data. The effect of organic compounds in the water on ozone absorption and liquid ozone concentration buildup was investigated experimentally using phenol as a model compound. It was found that the existence of phenol significantly reduced the liquid ozone concentration because absorbed ozone is consumed for the destruction of phenol, leading to the delay in liquid phase ozone concentration buildup. The implication is that the disinfection time was prolonged when water of high organic compounds concentration is to be purified. Using the completely stirred tank reactor model, the gas recycling is simulated and demonstrated to be effective for enhancing ozone utilization efficiency in the small portable water purification unit.
Adsorption and desorption of ammonium by clinoptilolite adsorbent in municipal wastewater treatment systems
Authors: Hedström Annelie , Rastas Amofah Lea
Published: April 2008

Natural zeolites as clinoptilolite may be used to recover wastewater ammonium, decrease the nitrogen content in the effluent from on-site sanitation systems and in wastewater treatment plants when nitrification–denitrification efficiency is low. The objective of this study was to estimate the ammonium adsorption capacity of clinoptilolite when being loaded with wastewater. Phosphorus and potassium sorption, ammonium desorption with tap water, and clogging were also studied. The study was performed by column experiments. Results of the investigation showed the ammonium adsorption capacity to increase with decreasing grain size, and the highest experimental adsorption capacity was 2.7 mg NH4-N/g. The breakthrough occurred immediately, probably due to a too high loading rate. Phosphorus and potassium sorption were minor. Of adsorbed ammonium, 23% was desorbed by tap water and desorption was more pronounced during saturated conditions. Filter clogging was extensive and probably caused by particles in the effluent wastewater and by microbiological growth.
Comparative studies of zinc, cadmium, lead and copper on economically viable adsorbents
Authors: Kaur Sumanjit , Walia T.P.S. , Mahajan R.K.
Published: April 2008

Lead and cadmium are very important metals even at trace levels because many health hazards are associated with them. Whereas, zinc and copper are toxic only when these are present at higher concentrations. Their removal from the contaminated samples is of utmost importance. The technique of adsorption using various economically viable adsorbents such as bagasse, bottom ash, rice husk ash, sawdust, and used tea leaves has been applied for their removal from aqueous solutions. Various parameters such as contact time, adsorbent dose, and metal concentrations were studied, optimized and applied to the present study. The equilibrium data obtained were analyzed in the light of Freundlich and Langmuir isotherms. Results revealed that rice husk ash is most efficient in removing lead and copper from aqueous solutions in comparison to the other adsorbents. Whereas in the case of cadmium, bottom ash was found to be of maximum efficiency. Bagasse was of maximum efficiency in removing zinc.
Management of waste from electrical and electronic equipment: The case of television sets and refrigerators
Authors: Rousis K. , Moustakas K. , Stylianou M. , Papadopoulos A. , Loizidou M.
Published: April 2008

Waste from electrical and electronic equipment (WEEE) constitutes one of the most complicated solid waste streams, in terms of its composition, and, as a result, it is difficult to be effectively managed. Waste from electrical and electronic equipment recycling is an important subject not only from the point of waste management, but also from the recovery of valuable materials. Characterization of this waste stream is of paramount importance for developing a cost-effective and environmentally friendly recycling system. Selective disassembly, targeting on singling out hazardous and (or) valuable components, is an indispensable process in the practice of WEEE recycling. It is very costly to perform manual dismantling of those products, due to the fact that brown goods contain very low-grade precious metals and copper. This work focuses on two major types of WEEE, television sets and refrigerators, giving analytical information on specific recovery and recycling procedures for their effective management.
Immunochemical studies and genetic background of twoNeisseria meningitidisisolates expressing unusual capsule polysaccharide antigens with specificities of both serogroup Y and W135
Authors: Tsang Raymond S.W. , Tsai Chao Ming , Henderson Averil M. , Tyler Shaun , Law Dennis K.S. , Zollinger Wendell , Jamieson Frances
Published: April 2008

We described 2 unusual Neisseria meningitidis strains isolated from epidemiologically unrelated invasive meningococcal disease cases in Ontario, Canada. Both isolates have features typical of serogroup Y N. meningitidis: are of serotype 2c, are of the multi-locus sequence types typical of the serogroup Y strains in Canada, and are genotyped as serogroup Y based on a previously described PCR–ELISA method that detects the serogroup-Y-specific siaD gene. However, both strains were poly-agglutinable in both anti-Y and anti-W135 antisera. Further studies on 1 of these 2 isolates showed the presence of glucose and galactose as well as sialic acids in its purified capsular polysaccharide, suggesting the presence of both serogroup Y and serogroup W135 polysaccharides. Rabbit antisera produced to this strain contained antibodies to both purified serogroup Y and serogroup W135 capsular polysaccharides. Absorption experiments with either serogroup Y or serogroup W135 bacteria confirmed the presence of antibodies to these 2 different polysaccharides. DNA sequencing of the cps operon from both isolates revealed a siaD gene with 99.7% homology to the published siaD sequence from a serogroup Y strain but with 3 point mutations that all resulted in amino acid changes. How these strains may affect results of routine surveillance, PCR diagnosis, and immuno-protection by vaccination are discussed.
Effect of anntrCmutation on amino acid or urea utilization and on nitrogenase switch-off inHerbaspirillum seropedicae
Authors: Gusso Claudio L. , de Souza Emanuel M. , Rigo Liu Un , de Oliveira Pedrosa Fábio , Yates M.G. , de M Rego Fabiane G. , Klassen Giseli
Published: April 2008

Herbaspirillum seropedicae is a nitrogen-fixing bacterium that grows well with ammonium chloride or sodium nitrate as alternative single nitrogen sources but that grows more slowly with l-alanine, l-serine, l-proline, or urea. The ntrC mutant strain DCP286A was able to utilize only ammonium or urea of these nitrogen sources. The addition of 1 mmol·L–1ammonium chloride to the nitrogen-fixing wild-type strain inhibited nitrogenase activity rapidly and completely. Urea was a less effective inhibitor; approximately 20% of nitrogenase activity remained 40 min after the addition of 1 mmol·L–1urea. The effect of the ntrC mutation on nitrogenase inhibition (switch-off) was studied in strain DCP286A containing the constitutively expressed gene nifA of H. seropedicae. In this strain, nitrogenase inhibition by ammonium was completely abolished, but the addition of urea produced a reduction in nitrogenase activity similar to that of the wild-type strain. The results suggest that the NtrC protein is required for assimilation of nitrate and the tested amino acids by H. seropedicae. Furthermore, NtrC is also necessary for ammonium-induced switch-off of nitrogenase but is not involved in the mechanism of nitrogenase switch-off by urea.
GENETIC ALGORITHM SOLUTION FOR MULTI-PERIOD TWO-ECHELON INTEGRATED COMPETITIVE/UNCOMPETITIVE FACILITY LOCATION PROBLEM
Authors: WANG XUE-FENG , SUN XIAO-MING , FANG YANG
Published: April 2008

This paper addresses the multi-period two-echelon integrated competitive/uncompetitive facility location problem in a distribution system design that involves locating regional distribution centers (RDCs) and stores, and determining the best strategy for distributing the commodities from a central distribution center (CDC) to RDCs and from RDCs to stores. The goal is to determine the optimal numbers, locations and capacities of RDCs and stores so as to maximize the total profit of the distribution system. Unlike most of past research, our study allows for dynamic planning horizon, distribution of commodities, configuration of two-echelon facilities, availability of capital for investment, external market competition, customer choice behavior and storage limitation. This problem is formulated as a bi-level programming model and a mutually consistent programming mode, respectively. Since such a distribution system design problem belongs to a class of NP-hard problem, a genetic algorithm-based heuristic (GA) is presented and compared with random search solution and mutually consistent solution (MC) using numerical example. The computational results show that the GA approach is efficient and the values of the performance index were significantly improved relative to the MC.
INVENTORY LOT-SIZE MODELS UNDER TRADE CREDITS: A REVIEW
Authors: CHANG CHUN-TAO , TENG JINN-TSAIR , GOYAL SURESH KUMAR
Published: April 2008

Since the publication of the Goyal model in 1985, research on the modeling of inventory lot-size under trade credits has resulted in a body of literature. In this paper, we present a review of the advances in inventory literature under conditions of permissible delay in payments since 1985. We classify all related previous articles into five categories based on: (a) without deterioration, (b) with deterioration, (c) with allowable shortage, (d) linked to order quantity, and (e) with inflation. The motivations, extensions and weaknesses of various previous models have been discussed in brief to bring out pertinent information regarding model developments in the past two decades.
OUTPUT FEEDBACK CONTROL FOR AN EXPLOITED STRUCTURED MODEL OF A FISHING PROBLEM
Authors: EL MAZOUDI E. , ELALAMI N. , MRABTI M.
Published: March 2008

In this paper, the problem of global state regulation via output feedback is investigated to study a structured fishing model, in order to stabilize its states around a non-trivial equilibrium. In our case, the two stages of the juvenile and adults ages of fish population are considered. In order to apply the tools of automatic control to our model, the fishing effort is used as a control term, the age classes as a states and the quantity of captured fish per unit of effort as a measured output. A Lyapunov function is adapted to study the stability and stabilization of the studied system around the non-trivial steady states. Numerical example demonstrates the effectiveness and the convergence of the states to the equilibrium.
PLATE-ROD SPINAL SYSTEM (PRSS) IN THE MANAGEMENT OF PROGRESSIVE EARLY ONSET SCOLIOSIS
Authors: Ye Qibin , Pang Xiaodong , Kuang Zhengda , Wang Wenjun
Published: March 2008

Objective: To determine the effectiveness and results of the plate-rod spinal system (PRSS) instrumentation in providing and maintaining scoliosis correction while allowing spinal growth in young children. Methods: From June 5, 2000, to July 10, 2006, a total of 23 patients with progressive early onset pediatric scoliosis underwent a one-stage PRSS procedure with no bony fusion. Analysis included age at surgery, measured changes in scoliosis angle, spinal growth, and complications. Results: The mean follow-up period was 2.8 ± 1.4 years, and more than 5 years in five cases. The mean correction varied from 80.7° to 30.5° after surgery, with a corrective rate of 62.2%. The average scoliotic curve in the latest follow-up was 34.7° (P > 0.05), indicting no significant loss of correction. The length of growth of the instrumented spine averaged 13.3 mm. No severe complications occurred in our series. Conclusion: The PRSS, which dispenses with bony fusion, is a safe and effective instrumentation for the management of juvenile scoliosis. It provides and maintains the desirable correction in a one-stage procedure, and allows continuous spinal growth.
NUMERICAL CHARACTERIZATION OF THE FLOW FIELD IN A FOUR-GENERATION AIRWAY
Authors: LAI T. C. , MORSI Y. S. , SINGH M.
Published: April 2008

In this paper, various aspects of respiratory airflow generated from the branching network of tubes that make up the tracheal-bronchial tree are numerically analyzed using the computational fluid dynamics (CFD) package CFX. The model used is a four-generation airway that is geometrically similar to Weibel's symmetrical model. In the present analysis, two different models (in-plane and off-plane) are examined for a wide range of Reynolds numbers that correspond to human breathing conditions. The findings indicate that the secondary flow patterns generated become more significant as the flow passes from the trachea to the fourth-generation airway. Moreover, comparison between in-plane and off-plane models shows that the skewed velocity profiles and secondary flows for the in-plane model are more prominent than those for the off-plane one. In general, the model developed in this study is capable of providing an overall insight into the effect of fluid flow in multiple generations of the human upper respiratory airways.
TITANIUM DIOXIDE NANOPARTICLES ASSEMBLED BY DNA MOLECULES HYBRIDIZATION AND LOADING OF DNA INTERACTING PROTEINS
Authors: WU AIGUO , PAUNESKU TATJANA , BROWN ERIC M. B. , BABBO ANGELA , CRUZ CECILLE , ASLAM MOHAMMED , DRAVID VINAYAK , WOLOSCHAK GAYLE E.
Published: March 2008

This work demonstrates the assembly of TiO 2 nanoparticles with attached DNA oligonucleotides into a 3D mesh structure by allowing base pairing between oligonucleotides. A change of the ratio of DNA oligonucleotide molecules and TiO 2 nanoparticles regulates the size of the mesh as characterized by UV-visible light spectra, transmission electron microscopy (TEM) and atomic force microscopy (AFM) images. This type of 3D mesh, based on TiO 2-DNA oligonucleotide nanoconjugates, can be used for studies of nanoparticle assemblies in materials science, energy science related to dye-sensitized solar cells, environmental science as well as characterization of DNA interacting proteins in the field of molecular biology. As an example of one such assembly, proliferating cell nuclear antigen protein (PCNA) was cloned, its activity was verified, and the protein was purified, loaded onto double strand DNA oligonucleotide- TiO 2 nanoconjugates, and imaged by atomic force microscopy. This type of approach may be used to sample and perhaps quantify and/or extract specific cellular proteins from complex cellular protein mixtures based on their affinity for chosen DNA segments assembled into the 3D matrix.
Activation of cytosolic phospholipase A2 and fatty acid transacylase is essential but not sufficient for thrombin-induced smooth muscle cell proliferation
Authors: Gluck Nathan , Schwob Ouri , Krimsky Miron , Yedgar Saul
Published: April 2008

Thrombin is a potent stimulant of smooth muscle cell (SMC) proliferation in inflammatory conditions, leading to pathological thickening of vascular walls in atherosclerosis and airway remodeling in asthma. Cell proliferation requires the formation and remodeling of cell membrane phospholipids (PLs), involving the activation of PL-metabolizing enzymes. Yet, the role of specific PL-metabolizing enzymes in SMC proliferation has hardly been studied. To bridge this gap, in the present study, we investigated the role of key enzymes involved in PL metabolism, the PL-hydrolyzing enzyme phospholipase A2 (PLA2) and the PL-synthesizing enzyme lysophosphatidic acid-fatty acid transacylase (LPAAT), in thrombin-induced proliferation of bovine aortic SMCs (BASMCs). Concomitantly with the induction of BASMC proliferation, thrombin activated cytosolic PLA2 (cPLA2-α), expressed by selective release of arachidonic acid and mRNA expression, as well as LPAAT, expressed by nonselective incorporation of fatty acid and mRNA expression. Specific inhibitors of these enzymes, arachidonyl-trifluoromethyl-ketone for cPLA2 and thimerosal for LPAAT, suppressed their activities, concomitantly with suppression of BASMC proliferation, suggesting a mandatory requirement for cPLA2 and LPAAT activation in thrombin-induced SMC proliferation. Thrombin acts through the protease-activated receptor (PAR-1), and, accordingly, we found that thrombin-induced BASMC proliferation was suppressed by the PAR-1 inhibitor SCH-79797. However, the PAR-1 inhibitor did not prevent thrombin-induced mRNA expression of cPLA2 and LPAAT, implying that the activation of cPLA2 and LPAAT is essential but not sufficient for thrombin-induced proliferation of BASMCs.
Aberrant cell-to-cell coupling in Ca2+-overloaded guinea pig ventricular muscles
Authors: Kurebayashi Nagomi , Nishizawa Hiroto , Nakazato Yuji , Kurihara Hidetake , Matsushita Satoshi , Daida Hiroyuki , Ogawa Yasuo
Published: April 2008

To investigate how intercellular coupling can be changed during Ca2+ overloading of ventricular muscle, we studied Ca2+ signals in individual cells and the histochemistry of the major gap junction channel, connexin43 (Cx43), using multicellular preparations. Papillary muscles were obtained from guinea pig ventricles and loaded with rhod-2. Sequential Ca2+ images of surface cells were obtained with a confocal microscope. In intact muscles, all cells showed simultaneous Ca2+ transients in response to field stimulation over a field of view of 0.3 × 0.3 mm2. In severely Ca2+-overloaded muscles, obtained by high-frequency stimulation in nonflowing Krebs solution, cells became less responsive to stimulation. Furthermore, nonsimultaneous but serial onsets of Ca2+ transients were often detected, suggesting a propagation delay of action potentials. The time lag of the onset between two aligned cells was sometimes as long as 100 ms. Similar lags were also observed in muscles with gap junction channels inhibited by heptanol. To investigate whether the phosphorylation state of Cx43 is affected in Ca2+-overloaded muscles, the distributions of phosphorylated and nonphosphorylated Cx43 were determined using specific antibodies. Most of the Cx43 was phosphorylated in the nonoverloaded muscles, whereas nonphosphorylated Cx43 was significantly elevated in severely Ca2+-overloaded muscles. Our results suggest that the propagation delay of action potential within a small area, a few square millimeters, can be a cause of abnormal conduction and a microreentry in Ca2+-overloaded heart. Inactivation of Na+ channels and inhibition of gap junctional communication may underlie the cell-to-cell propagation delay.
Neonatal stem cells exhibit specific characteristics in function, proliferation, and cellular signaling that distinguish them from their adult counterparts
Authors: Markel Troy A. , Wang Meijing , Crisostomo Paul R. , Manukyan Maiuxi C. , Poynter Jeffrey A. , Meldrum Daniel R.
Published: April 2008

Stem cells may be a novel treatment modality for organ ischemia, possibly through beneficial paracrine mechanisms. Stem cells from older hosts have been shown to exhibit decreased function during stress. We therefore hypothesized that 1) neonatal bone marrow mesenchymal stem cells (nBMSCs) would produce different levels of IL-6, VEGF, and IGF-1 compared with adults (aBMSCs) when stimulated with TNF or LPS; 2) differences in cytokines would be due to distinct cellular characteristics, such as proliferation or pluripotent potential; and 3) differences in cytokines would be associated with differences in p38 MAPK and ERK signaling within nBMSCs. BMSCs were isolated from adult and neonatal mice. Cells were exposed to TNF or LPS with or without p38 or ERK inhibition. Growth factors were measured via ELISA, proliferation via daily cell counts, cell surface markers via flow cytometry, and pluripotent potential via alkaline phosphatase activity. nBMSCs produced lower levels of IL-6 and VEGF, but higher levels of IGF-1 under basal conditions, as well as after stimulation with TNF, but not LPS. Neonatal and adult BMSCs had similar pluripotent potentials and cell surface markers, but nBMSCs proliferated faster. Furthermore, p38 and ERK appeared to play a more substantial role in nBMSC cytokine and growth factor production. Neonatal stem cells may aid in decreasing the local inflammatory response during ischemia, and could possibly be expanded more rapidly than adult cells prior to therapeutic use.
The high-fat-fed lean Zucker rat: a spontaneous isocaloric model of fat-induced insulin resistance associated with muscle GSK-3 overactivity
Authors: Henriksen Erik J. , Teachey Mary K. , Lindborg Katherine A. , Diehl Cody J. , Beneze Alan N.
Published: April 2008

High-fat feeding (HFF) is a well-accepted model for nutritionally-induced insulin resistance. The purpose of this investigation was to assess the metabolic responses of female lean Zucker rats provided regular chow (4% fat) or a high-fat chow (50% fat) for 15 wk. HFF rats spontaneously adjusted food intake so that daily caloric intake matched that of chow-fed (CF) controls. HFF animals consumed more ( P < 0.05) calories from fat (31.9 ± 1.2 vs. 2.4 ± 0.2 kcal/day) and had significantly greater final body weights (280 ± 10 vs. 250 ± 5 g) and total visceral fat (24 ± 3 vs. 10 ± 1 g). Fasting plasma insulin was 2.3-fold elevated in HFF rats. Glucose tolerance (58%) and whole body insulin sensitivity (75%) were markedly impaired in HFF animals. In HFF plantaris muscle, in vivo insulin receptor β-subunit (IR-β) and insulin receptor substrate-1 (IRS-1) tyrosine phosphorylation and phosphorylation of Akt Ser473 and glycogen synthase kinase-3β (GSK-3β) Ser9, relative to circulating insulin levels, were decreased by 40–59%. In vitro insulin-stimulated glucose transport in HFF soleus was decreased by 54%, as were IRS-1 tyrosine phosphorylation (26%) and phosphorylation of Akt Ser473 (38%) and GSK-3β Ser9 (25%), the latter indicative of GSK-3 overactivity. GSK-3 inhibition in HFF soleus using CT98014 increased insulin-stimulated glucose transport (28%), IRS-1 tyrosine phosphorylation (28%) and phosphorylation of Akt Ser473 (38%) and GSK-3β Ser9 (48%). In summary, the female lean Zucker rat fed a high-fat diet represents an isocaloric model of nutritionally-induced insulin resistance associated with moderate visceral fat gain, hyperinsulinemia, and impairments of skeletal muscle insulin-signaling functionality, including GSK-3β overactivity.
Hepatic insulin resistance induced by prenatal alcohol exposure is associated with reduced PTEN and TRB3 acetylation in adult rat offspring
Authors: Yao Xing-Hai , Nyomba B. L. Grégoire
Published: April 2008

Prenatal alcohol exposure (EtOH) results in insulin resistance in rats of both sexes with increased expression of hepatic gluconeogenic genes and glucose production. To investigate whether hepatic insulin signaling is defective, we studied 3-mo-old female offspring of dams that were given EtOH during pregnancy compared with those from pair-fed and control dams. We performed an intraperitoneal pyruvate tolerance test, determined the phosphorylation status of hepatic phosphoinositide-dependent protein kinase-1 (PDK1), Akt, and PKCζ before and after intravenous insulin bolus, and measured mRNA and in vivo acetylation of TRB3 (tribbles 3) and PTEN (phosphatase and tensin homolog deleted on chromosome ten) as well as the expression of the histone acetylase (HAT) PCAF (p300/CREB-binding protein-associated factor), histone deacetylase-1 (HDAC1), and HAT and HDAC activities. In EtOH compared with pair-fed and control offspring, basal and pyruvate-induced blood glucose was increased, insulin-induced PDK1, Akt, and PKCζ phosphorylation was reduced, and expression of PTEN and TRB3 was increased while their acetylation status was decreased in association with increased HDAC and decreased HAT activities. Thus female adult rats prenatally exposed to EtOH have increased gluconeogenesis, reduced insulin signaling, and increased PTEN and TRB3 expression in the liver. In addition, PTEN and TRB3 are hypoacetylated, which can contribute to Akt-inhibiting activity. These results suggest that hepatic insulin resistance in rats prenatally exposed to EtOH is explained, at least in part, by increased PTEN and TRB3 activity due to both increased gene expression and reduced acetylation.
The bone-muscle ratio of fetal lambs is affected more by maternal nutrition during pregnancy than by maternal size
Authors: Firth E. C. , Rogers C. W. , Vickers M. , Kenyon P. R. , Jenkinson C. M. C. , Blair H. T. , Johnson P. L. , Mackenzie D. D. S. , Peterson S. W. , Morris S. T.
Published: April 2008

Bone formation and loss are related to the strain imposed on bone by muscle forces. Bone mineral content (BMC) and lean mass (LM) of fetal lambs was determined at day 140 of pregnancy in 8 groups of ewes, which were of either large or small body size, on either high (ad libitum) or maintenance pasture intake from day 21 of pregnancy, or carrying either singletons or twins. BMC and LM (using DXA scanning) of fetal hindquarters/spine were corrected to leg length. BMC and LM were less in twin than singleton groups ( P < 0.001). Large ewes on high intake produced single fetuses with a (group mean) BMC/LM ratio that was higher ( P < 0.002) than that in fetuses of large ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. In single fetuses from small ewes on high intake, the BMC/LM ratio was higher than those from small ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. The ratio was not different in singleton fetuses of ewes on high intake, whether they were large or small. Different fetal environments resulted in a given amount of muscle being associated with a higher or lower bone mass. Dietary intake during pregnancy was more important than maternal size in affecting the ratio. We conclude that intrauterine environmental factors may be important in determining bone mass postnatally, and possibly later in life.
Increased inorganic phosphate induces human endothelial cell apoptosis in vitro
Authors: Di Marco G. S. , Hausberg M. , Hillebrand U. , Rustemeyer P. , Wittkowski W. , Lang D. , Pavenstädt H.
Published: April 2008

Chronic kidney disease with hyperphosphatemia is associated with accelerated atherosclerosis and endothelial dysfunction. However, the contribution of high serum phosphate levels to endothelial injury is incompletely understood. The aim of this work was to evaluate the responses of endothelial cells to elevated levels of extracellular phosphate in vitro. High phosphate in concentrations similar to those observed in uremia-associated hyperphosphatemia (>2.5 mM) induced apoptosis in two endothelial cell lines (EAhy926 cells and GM-7373 cells). This effect was enhanced when cells were incubated for 24 h in the presence of 2.8 mM calcium instead of 1.8 mM. By treating cells with 0.5 or 1.0 mM phosphonoformic acid, an inhibitor of the phosphate transporter, death was completely prevented. The process of phosphate-induced apoptosis was further characterized by increased oxidative stress, as detected by increased ROS generation and disruption of the mitochondrial membrane potential at ∼2 h after treatment, followed by caspase activation. These findings show that hyperphosphatemia causes endothelial cell apoptosis, a process that impairs endothelial integrity. Endothelial cell injury induced by high phosphate concentrations may be an initial event leading to vascular complications in patients with chronic kidney disease.
Mechanisms of Neuromodulation as Dissected Using Sr2+at Motor Nerve Endings
Authors: Searl Timothy J. , Silinsky Eugene M.
Published: April 2008

The use of binomial analysis as a tool for determining the sites of action of neuromodulators may be complicated by the nonuniformity of release probability. One of the potential sources for nonuniformity of release probability is the presence of multiple forms of synaptotagmins, the Ca2+sensors responsible for triggering vesicular exocytosis. In this study we have used Sr2+, an ion whose actions may be restricted to a subpopulation of synaptotagmins, in an attempt to obtain meaningful estimates of the binomial parameters p (the probability of evoked acetylcholine [Ach] release) and n (the immediate available store of ACh quanta, whereby m = np). In contrast to results in Ca2+solutions, binomial analysis of Sr2+-dependent release reveals a dramatically reduced dependence of n on extracellular Sr2+concentrations. In Sr2+solutions, blockade of potassium channels with 3,4-diaminopyridine increased m by an exclusive increase in p, whereas treatment with phorbol ester increased m solely by effects on n. The cyclic adenosine monophosphate (cAMP) analogue CPT-cAMP increased m by increasing both n and p. The effect of CPT-cAMP on p but not on n was blocked by protein kinase A (PKA) inhibitors, whereas the effect on n was mimicked by 8-CPT-2′-O-Me-cAMP, a selective agonist for exchange protein directly activated by cAMP, otherwise known as the cAMP-sensitive guanine nucleotide-exchange protein. The results demonstrate both the utility of the binomial distribution in Sr2+solutions and the dual effects of cyclic AMP on both PKA-dependent and PKA-independent processes at the amphibian neuromuscular junction.
Fluorescence Resonance Energy Transfer in Quantum Dot-Protein Kinase Assemblies
Authors: Yildiz Ibrahim , Gao Xinxin , Harris Thomas K. , Raymo Françisco M.
Published: March 2008

In search of viable strategies to identify selective inhibitors of protein kinases, we have designed a binding assay to probe the interactions of human phosphoinositide-dependent protein kinase-1 (PDK1) with potential ligands. Our protocol is based on fluorescence resonance energy transfer (FRET) between semiconductor quantum dots (QDs) and organic dyes. Specifically, we have expressed and purified the catalytic kinase domain of PDK1 with an N-terminal histidine tag [His6-PDK1(ΔPH)]. We have conjugated this construct to CdSe-ZnS core-shell QDs coated with dihydrolipoic acid (DHLA) and tested the response of the resulting assembly to a molecular dyad incorporating an ATP ligand and a BODIPY chromophore. The supramolecular association of the BODIPY-ATP dyad with theHis6-PDK1(ΔPH)-QD assembly encourages the transfer of energy from the QDs to the BODIPY dyes upon excitation. The addition of ATP results in the displacement of BODIPY-ATP from the binding domain of theHis6-PDK1(ΔPH) conjugated to the nanoparticles. The competitive binding, however, does not prevent the energy transfer process. A control experiment with QDs, lacking theHis6-PDK1(ΔPH), indicates that the BODIPY-ATP dyad adsorbs nonspecifically on the surface of the nanoparticles, promoting the transfer of energy from the CdSe core to the adsorbed BODIPY dyes. Thus, the implementation of FRET-based assays to probe the binding domain of PDK1 with luminescent QDs requires the identification of energy acceptors unable to interact nonspecifically with the surface of the nanoparticles.
Recent Advances in Organic Solar Cells
Authors: Kietzke Thomas
Published: March 2008

Solar cells based on organic semiconductors have attracted much attention. The thickness of the active layer of organic solar cells is typically only 100 nm thin, which is about 1000 times thinner than for crystalline silicon solar cells and still 10 times thinner than for current inorganic thin film cells. The low material consumption per area and the easy processing of organic semiconductors offer a huge potential for low cost large area solar cells. However, to compete with inorganic solar cells the efficiency of organic solar cells has to be improved by a factor of 2-3. Several organic semiconducting materials have been investigated so far, but the optimum material still has to be designed. Similar as for organic light emitting devices (OLED) small molecules are competing with polymers to become the material of choice. After a general introduction into the device structures and operational principles of organic solar cells the three different basic types (all polymer based, all small molecules based and small molecules mixed with polymers) are described in detail in this review. For each kind the current state of research is described and the best of class reported efficiencies are listed.
Luminescence, Energy Transfer, and Upconversion Mechanisms of Y2O3Nanomaterials Doped with Eu3+,Tb3+, Tm3+,Er3+, and Yb3+Ions
Authors: Anh TranKim , Benalloul Paul , Barthou Charles , Giang Lam thiKieu , Vu Nguyen , Minh LeQuoc
Published: March 2008

Luminescence, energy transfer, and upconversion mechanisms of nanophosphors (Y2O3 : Eu3+,Tb3+,Y2O3 : Tm3+,Y2O3 : Er3+,Yb3+) both in particle and colloidal forms were studied. The structure, phase, and morphology of the nanopowders and nanocolloidal media were determined by high-resolution TEM and X-ray diffraction. It was shown that the obtained nanoparticles have a round-spherical shape with average size in the range of 4 to 20 nm. Energy transfer was observed forY2O3 : Eu3+,Tb3+colloidal and powders, upconversion transitions were observed for bothY2O3 : Er3+andY2O3 : Er3+,Yb3+nanophosphors. The dependence of photoluminescence (PL) spectra and decay times on doping concentration has been investigated. The infrared to visible conversion of emission inY2O3 : Er3+,Yb3+system was analyzed and discussed aiming to be applied in the photonic technology.
Fluorescence Intensity and Intermittency as Tools for Following Dopamine Bioconjugate Processing in Living Cells
Authors: Khatchadourian Rafael , Bachir Alexia , Clarke Samuel J. , Heyes Colin D. , Wiseman Paul W. , Nadeau Jay L.
Published: March 2008

CdSe/ZnS quantum dots (QDs) conjugated to biomolecules that quench their fluorescence, particularly dopamine, have particular spectral properties that allow determination of the number of conjugates per particle, namely, photoenhancement and photobleaching. In this work, we quantify these properties on a single-particle and ensemble basis in order to evaluate their usefulness as a tool for indicating QD uptake, breakdown, and processing in living cells. This creates a general framework for the use of fluorescence quenching and intermittency to better understand nanoparticle-cell interactions.
A Strongly Interacting Dynamic Particle Swarm Optimization Method
Authors: Kok S. , Snyman J. A.
Published: April 2008

A novel dynamic interacting particle swarm optimization algorithm (DYN‐PSO) is proposed. The algorithm can be considered to be the synthesis of two established trajectory methods for unconstrained minimization. In the new method, the minimization of a function is achieved through the dynamic motion of a strongly interacting particle swarm, where each particle in the swarm is simultaneously attracted by all other particles located at positions of lower function value. The force of attraction experienced by a particle at higher function value due to a particle at a lower function value is equal to the difference between the respective function‐values divided by their stochastically perturbed position difference. The resultant motion of the particles under the influence of the attracting forces is computed by solving the associated equations of motion numerically. An energy dissipation strategy is applied to each particle. The specific chosen force law and the dissipation strategy result in the rapid collapse (convergence) of the swarm to a stationary point. Numerical results show that, in comparison to the standard particle swarm algorithm, the proposed DYN‐PSO algorithm is promising.
An Analytical Prediction Model of Time Diversity Performance for Earth‐Space Fade Mitigation
Authors: Arapoglou Pantelis-Daniel M. , Panagopoulos Athanasios D. , Cottis Panayotis G.
Published: March 2008

Time diversity (TD) has recently attracted attention as a promising and cost‐efficient solution
for high‐frequency broadcast satellite applications. The present work proposes a general
prediction model for the application of TD by approximating the time dynamics of rain attenuation
through the use of the joint lognormal distribution. The proposed method is tested against experimental
data and its performance is investigated with respect to the basic parameters of a satellite link.
Photo‐Oxidation of Water Using Nanocrystalline Tungsten Oxide under Visible Light
Authors: Hamilton J. W. J. , Byrne J. A. , Dunlop P. S. M. , Brown N. M. D.
Published: March 2008

The photoelectrolysis of water to yield hydrogen and oxygen
using visible light has enormous potential for solar energy harvesting if suitable photoelectrode materials can be developed. Few of the materials with a band gap suitable for visible light activation have the necessary band‐edge potentials or photochemical stability to be suitable candidates. Tungsten oxide (Ebg 2.8 eV) is a good candidate with absorption up to λ ≈ 440 nm and known photochemical stability. Thin films of tungsten oxide were prepared using an electrolytic route from peroxo‐tungsten precursors. The tungsten oxide thin films were characterised by FESEM, Auger electron spectroscopy, and photoelectrochemical methods. The magnitude of the photocurrent response of the films under solar simulated irradiation showed a dependence on precursor used in the film preparation, with a comparatively lower response for samples containing impurities. The photocurrent response spectrum of the tungsten oxide films was more favourable than that recorded for titanium dioxide (TiO2) thin films. The WO3 photocurrent response was of equivalent magnitude but shifted into the visible region of the spectrum, as compared to that of the TiO2.
Silica-Copper Oxide Composite Thin Films as Solar Selective Coatings Prepared by Dipping Sol Gel
Authors: Barrera-Calva E. , Méndez-Vivar J. , Ortega-López M. , Huerta-Arcos L. , Morales-Corona J. , Olayo-González R.
Published: March 2008

Silica-copper oxide (silica-CuO) composite thin films were prepared by a dipping sol-gel route using ethanolic solutions comprised TEOS and a copper-propionate complex. Sols with different TEOS/Cu-propionate (Si/Cu) molar ratios were prepared and applied on stainless steel substrates using dipping process. During the annealing process, copper-propionate complexes developed into particulate polycrystalline CuO dispersed in a partially crystallized silica matrix, as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The gel thermal analysis revealed that the prepared material might be stable up to400°C. The silica-CuO/stainless steel system was characterized as a selective absorber surface and its solar selectivity parameters, absorptance (α), and emittance (ε) were evaluated from UV-NIR reflectance data. The solar parameters of such a system were mostly affected by the thickness and phase composition of theSiO2-CuO film. Interestingly, the best solar parameters (α= 0.92 andε= 0.2) were associated to the thinnest films, which comprised a CuO-Cu2Omixture immersed in the silica matrix, as indicated by XPS.
Weak Approximation of SDEs by Discrete‐Time Processes
Authors: Zähle Henryk
Published: March 2008

We consider the martingale problem related to the solution of an SDE on the line. It is shown that the solution of this martingale problem can be approximated by solutions of the corresponding time‐discrete martingale problems under some conditions. This criterion is especially expedient for establishing the convergence of population processes to SDEs. We also show that the criterion yields a weak Euler scheme approximation of SDEs under fairly weak assumptions on the driving force of the approximating processes.
Some New Inclusion and Neighborhood Properties forCertain Multivalent Function Classes Associated with the Convolution Structure
Authors: Prajapat J. K. , Raina R. K.
Published: March 2008

We use the familiar convolution structure of analytic functions to introduce
two new subclasses of multivalently analytic functions of complex order, and prove several inclusion relationships
associated with the (n, δ)‐neighborhoods for these subclasses. Some interesting consequences
of these results are also pointed out.
Using a Camera Phone as a Mixed‐Reality Laser Cannon
Authors: Chehimi Fadi , Coulton Paul , Edwards Reuben
Published: March 2008

Despite the ubiquity and rich features of current mobile phones, mobile games have failed to reach even the lowest estimates of expected revenues. This is unfortunate as mobile phones offer unique possibilities for creating games aimed at
attracting demographics not currently catered for by the traditional console market. As a result, there has been a growing
call for greater innovation within the mobile games industry and support for games outside the current console
genres. In this paper, we present the design and implementation of a novel location‐based game which allows us turn a camera phone into a mixed‐reality laser cannon. The game uses specially designed coloured tags, which are worn by the players, and advanced colour tracking software running on a camera phone, to create a novel first person shoot‐em‐up (FPS) with innovative game interactions and play.
Enabling VLSI Processing Blocks for MIMO‐OFDM Communications
Authors: Cerato Barbara , Masera Guido , Viterbo Emanuele
Published: March 2008

Multi‐input multi‐output (MIMO) systems combined
with orthogonal frequency‐division multiplexing (OFDM)
gained a wide popularity in wireless applications due to the
potential of providing increased channel capacity and robustness
against multipath fading channels. However these advantages
come at the cost of a very high processing complexity and
the efficient implementation of MIMO‐OFDM receivers is today
a major research topic. In this paper, efficient architectures
are proposed for the hardware implementation of the main
building blocks of a MIMO‐OFDM receiver. A sphere decoder
architecture flexible to different modulation without any loss in
BER performance is presented while the proposed matrix factorization
implementation allows to achieve the highest throughput
specified in the IEEE 802.11n standard. Finally a novel E8 sphere
decoder approach is presented, which allows for the realization of
new golden space time trellis coded modulation (GST‐TCM)
scheme. Implementation cost and offered throughput are provided
for the proposed architectures synthesized on a 0.13 μm CMOS
standard cell technology or on advanced FPGA devices.
LMI Conditions for Robust Stability of 2D Linear Discrete‐Time Systems
Authors: Hmamed A. , Alfidi M. , Benzaouia A. , Tadeo F.
Published: March 2008

Robust stability conditions are derived for uncertain 2D linear discrete‐time systems,
described by Fornasini‐Marchesini second models with polytopic uncertainty. Robust stability is
guaranteed by the existence of a parameter‐dependent Lyapunov function obtained from the feasibility
of a set of linear matrix inequalities, formulated at the vertices of the uncertainty polytope.
Several examples are presented to illustrate the results.
Determination of Bolus Dielectric Constant for Optimum Coupling of Microwaves through Skin for Breast Cancer Imaging
Authors: Rappaport Carey
Published: March 2008

We find the complex dielectric constant of the bolus liquid with the best microwave impedance match to skin‐covered fatty breast tissue. The real dielectric constant and conductivity of the ideal medium are determined by minimizing the magnitude of the reflection coefficient from the two‐interface frequency‐dependent system, using published measured skin and breast fat dielectric characteristics in the 400 MHz to 10 GHz frequency range. Error bounds are provided to indicate the coupling degradation when using real, nonideal media for the bolus liquid. Two frequency regimes are identified. Below 6.45 GHz, conventional liquid mixtures can approach the optimal coupling permittivity, but the reflection magnitudes for these best cases are high. Above 6.45 GHz, perfect coupling is possible, but only for impractically high values of bolus dielectric constant and loss.