bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photopolymerization with microscale resolution: Influence of the physico‐chemical and photonic parameters
Authors: Soppera Olivier , Jradi Safi , Lougnot Daniel J. 
Published: April 2008

AbstractThis article is aimed at demonstrating that physicochemical parameters can be used to control the spatial extent (length, width, and shape) of polymer objects in view of micro‐ and nano‐fabrication applications. In particular, we showed that oxygen quenching and internal filter effects could be turned to advantage to modulate the response of the material by controlling the threshold energy of polymerization and/or the shape of the light into the photopolymerizable medium. The experimental configuration used in this study is based on light‐induced polymerization at the extremity of an optical fiber that produces polymer micro‐objects after development. Spectroscopic approaches and polymerization threshold measurements were performed to quantitatively evaluate the influence of the physicochemical parameters on the micropatterning of photopolymerizable material. Interestingly, fluorescence that is usually regarded as a process competing with photopolymerization reaction, was used for controlling the fabrication process. By this means, it was possible to better understand the impact of a nonhomogeneous irradiation on photopolymerization process and thus, to tune the shape and the size of the final polymer objects. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3783–3794, 2008
Synthesis and characterization of a series of biodegradable and biocompatible PEG‐supported poly(lactic‐ran‐glycolic acid) amphiphilic barbell‐like copolymers
Authors: Lu De Dai , Yuan Jian Chao , Li Hongguang , Lei Zi‐Qiang 
Published: April 2008

AbstractA series of multihydroxyl (2, 4, and 8) terminated poly(ethylene glycol)s and their biodegradable, biocompatible, and branched barbell‐like (PLGA)n‐b‐PEG‐b‐(PLGA)n (n = 1, 2, 4) copolymers have been synthesized. The lengths of the PLGA arms were varied by controlling the molar ratio of monomers to hydroxyl groups of PEG ([LA+GA]0/[OH]0 = 23, 45, 90). Chemical structures of synthesized barbell‐like copolymers were confirmed by both 1H and 13C‐NMR spectroscopies. Molecular weights were determined by 1H‐NMR end‐group analysis and gel permeation chromatography. The result of hydrolytic degradation indicated that the rate of degradation increased with the increase of arm numbers or with the decrease of arm lengths. The thermal properties were evaluated by using differential scanning calorimetry and a thermogravimetric analysis. The results indicated that the thermal properties of barbell‐like copolymers depended on the structural variations. The morphology of (PLGA)n‐PEG‐(PLGA)n copolymers self‐assembly films were investigated by atomic force microscope, the results indicated that the microphase separation existed in (PLGA)n‐PEG‐(PLGA)n copolymers. Because of the favorable biodegradability and biocompatibility of the PLGA and PEG, these results may therefore create new possibilities for these novel structural amphiphilic barbell‐like copolymers as potential biomaterials. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3802–3812, 2008
Benzophenothiazine and benzophenoxazine photosensitizers for triarylsulfonium salt cationic photoinitiators
Authors: Crivello James V. 
Published: April 2008

AbstractAn investigation of the photosensitization of triarylsulfonium salts at wavelengths greater than 400 nm was carried out with phenothiazine and phenoxazine compounds possessing extended benzenoid conjugation. Accordingly, three isomeric benzophenothiazines and 12H‐benzo[b]phenoxazine were prepared and employed for the photosensitization of several different types of triarylsulfonium salts. These compounds display a tail absorption that extends at least to 450 nm, making them useful for conducting photopolymerizations using long wavelength emission sources. The photosensitized vinyl and ring‐opening polymerizations of a number of monomers were conducted and the results are reported in this communication. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3820–3829, 2008
Effects of Oral Administration of Stephania tetrandra S. Moore on Neovascularization of Retinal and Choroidal Capillaries of Diabetes in Rats
Authors: Tsutsumi Taiki , Hagino Nobuyoshi , Liang Xiao‐chun , Guo Sai‐shan , Kobayashi Shinjiro 
Published: April 2008

AbstractIn rats, an injection of streptozotocin (STZ) elevated blood levels of glucose 4 weeks later (STZ‐induced diabetes) and an over‐production of microvessels of retinal and choroidal capillaries of eyes developed. A previous study has shown that administration of Stephania tetrandra S. Moore (STSM) in culture prevented the over‐production of microvessels of those capillaries of STZ‐induced diabetes in vitro. Therefore, the study investigated whether or not orally administered STSM could inhibit over‐production of microvessels of those capillaries of STZ injected rats in vivo. When STSM was given at the same time as the STZ injection and continued daily for 7 weeks, STSM prevented the elevation of blood glucose level and over‐production of microvessels of those capillaries. When STSM was given after elevation of blood glucose level of glucose (4 weeks after STZ injection) and continued daily for 4 weeks, STSM lowered the elevated blood glucose level but had no effect on the over‐production of microvessels of those capillaries. It was inferred that deposition of Nϵ(carboxymethyl) lysine in retinal and choroidal tissues, which is induced by STZ‐induced diabetes may deteriorate the blood–retinal barrier and the blood–choroidal barrier. One might, therefore, speculate that advanced STZ‐induced diabetes may deteriorate the blood–retinal barrier and blood–choroidal barrier. Therefore, STSM may not reach the retinal and choroidal tissues in the posterior ocular region in vivo. Copyright © 2008 John Wiley & Sons, Ltd.
Antihyperglycemic and hypolipidemic effects of Costus speciosus in alloxan induced diabetic rats
Authors: Bavarva Jasmin H. , Narasimhacharya A. V. R. L. 
Published: April 2008

AbstractHyperglycemia, abnormal lipid and antioxidant profiles are the most usual complications in diabetes mellitus. In the present study, the antihyperglycemic, antihyperlipemic and antioxidant potency of an ethanol extract of Costus speciosus root was investigated in alloxan‐induced diabetic male (Charles Foster) rats. Four groups of alloxan diabetic rats (n = 6) were administered orally with different doses of Costus speciosus root extract (150, 300 and 450 mg/kg BW) and a standard drug, glibenclamide (600 µg/kg BW), for 4 weeks. Two groups of rats (n = 6) served as normal and diabetic controls. While the diabetic controls showed significant abnormal carbohydrate, lipid and antioxidant profiles, administration of 150 mg/kg BW dose neither improved glucose nor lipid metabolism and antioxidant levels. Administration of 300 and 450 mg/kg BW doses, however, resulted in a reversal of diabetes and its complications. Both doses significantly brought down blood glucose concentration (26.76%, 34.68%), increased glycogenesis and decreased glyconeogenesis bringing the glucose metabolism toward normalcy. These doses also reversed the hyperlipidemia by reducing plasma total lipid (12.87%, 178.24%), cholesterol (21.92%, 30.77%) and triglyceride (25.32%, 33.99%) and improved hepatic antioxidant enzyme activities. The high dose (450 mg/kg BW) was found to have more potential antioxidant activities compared with glibenclamide. It is concluded that Costus speciosus root extract possesses anti‐hyperglycemic, antihyperlipemic and antioxidative effects, which may prove to be of clinical importance in the management of diabetes and its complications. Copyright © 2008 John Wiley & Sons, Ltd.
Print uniformity of corrugated board in flexo printing: effects of corrugated board and halftone dot deformations
Authors: Holmvall Martin , Uesaka Tetsu 
Published: April 2008

AbstractPrint non‐uniformity is a major concern for flexo post‐printers. Many of these non‐uniformities are suspected to be caused by the corrugated board structure itself. Striping is the most obvious one, but also other print quality problems might be structure‐related. This work focuses on how deformations of the board might lead to print non‐uniformities, and if the deformation of halftone dots is the mechanism behind striping in halftone flexo post‐printing. Finite element models were used to analyse the effects of deformations of corrugated boards and compressed halftone dots in the printing nip. Distortions of the board due to non‐uniform hygro‐thermal strains were shown to be a potential cause of print non‐uniformities. Striping in halftone prints was found to be caused by differences in dot gain between areas above ridges and valleys of the flute structure. Copyright © 2008 John Wiley & Sons, Ltd.
Using δ15N and δ18O to evaluate the sources and pathways of NO in rainfall event discharge from drained agricultural grassland lysimeters at high temporal resolutions
Authors: Granger Steven J. , Heaton Tim H.E. , Bol Roland , Bilotta Gary S. , Butler Patricia , Haygarth Philip M. , Owens Philip N. 
Published: April 2008

AbstractThe origin of NO yielded in drainage from agricultural grasslands is of environmental significance and has three potential sources; (i) soil organic mater (SOM), (ii) recent agricultural amendments, and (iii) atmospheric inputs. The variation in δ15N‐NO and δ18O‐NO was measured from the ‘inter‐flow’ and ‘drain‐flow’ of two 1 ha drained lysimeter plots, one of which had received an application of 21 m3 of NH‐N‐rich agricultural slurry, during two rainfall events. Drainage started to occur 1 month after the application of slurry. The concentrations of NO‐N from the two lysimeters were comparable; an initial flush of NO‐N occurred at the onset of drainage from both lysimeters before levels quickly dropped to <1 mg NO‐N L−1. The isotopic signature of the δ15N‐NO and δ18O‐NO during the first two rainfall events showed a great deal of variation over short time‐periods from both lysimeters. Isotopic variation of δ15N‐NO during rainfall events ranged between −1.6 to +5.2‰ and +0.4 to +11.1‰ from the inter‐flow and drain‐flow, respectively. Variation in the δ18O‐NO ranged from +2.0 to +7.8‰ and from +3.3 to +8.4‰. No significant relationships between the δ15N‐NO or δ18O‐NO and flow rate were observed in most cases although δ18O‐NO values indicated a positive relationship and δ15N‐NO values a negative relationship with flow during event 2. Data from a bulked rainfall sample when compared with the theoretical δ18O‐NO for soil microbial NO indicated that the contribution of rainfall NO accounted for 8% of the NO in the lysimeter drainage at most. The calculated contribution of rainfall NO was not enough to account for the depletion in δ15N‐NO values observed during the duration of the rainfall event 2. The relationship between δ15N‐NO and δ18O‐NO from the drain‐flow indicated that denitrification was causing enrichment in the isotopes from this pathway. The presence of slurry seemed to cause a relative depletion in δ18O‐NO in the inter‐flow and δ15N‐NO in the drain‐flow compared with the zero‐slurry lysimeter. This may have been caused by increased microbial nitrification stimulated by the presence of increased NH‐N. Copyright © 2008 John Wiley & Sons, Ltd.
Direct adaptive control of a utility‐scale wind turbine for speed regulation
Authors: Frost Susan A. , Balas Mark J. , Wright Alan D. 
Published: April 2008

AbstractThe accurate modeling of wind turbines is an extremely challenging problem due to the tremendous complexity of the machines and the turbulent and unpredictable conditions in which they operate. Adaptive control techniques are well suited to nonlinear applications, such as wind turbines, which are difficult to accurately model and which have effects from poorly known operating environments. In this paper, we extended the direct model reference adaptive control (DMRAC) approach to track a reference point and to reject persistent disturbances. This approach was then used to design an adaptive collective pitch controller for a high‐fidelity simulation of a variable‐speed horizontal axis wind turbine. The objective of the adaptive pitch controller was to regulate generator speed in Region 3 and to reject step disturbances. The control objective was accomplished by collectively pitching the turbine blades.The turbine simulation models the controls advanced research turbine (CART) of the National Renewable Energy Laboratory in Golden, Colorado. The CART is a utility‐scale wind turbine that has a well‐developed and extensively verified simulator. This novel application of adaptive control was compared in simulations with a classical proportional integrator (PI) collective pitch controller. In the simulations, the adaptive pitch controller showed improved speed regulation in Region 3 when compared with the PI pitch controller. Copyright © 2008 John Wiley & Sons, Ltd.
Testing whether genetic variation explains correlation of quantitative measures of gene expression, and application to genetic network analysis
Authors: Yu Zhaoxia , Wang Liewei , Hildebrandt Michelle A. T. , Schaid Daniel J. 
Published: April 2008

AbstractGenetic networks for gene expression data are often built by graphical models, which in turn are built from pair‐wise correlations of gene expression levels. A key feature of building graphical models is the evaluation of conditional independence of two traits, given other traits. When conditional independence can be assumed, the traits that are conditioned on are considered to ‘explain’ the correlation of a pair of traits, allowing efficient building and interpretation of a network. Overlaying genetic polymorphisms, such as single nucleotide polymorphisms (SNPs), on quantitative measures of gene expression provides a much richer set of data to build a genetic network, because it is possible to evaluate whether sets of SNPs ‘explain’ the correlation of gene expression levels. However, there is strong evidence that gene expression levels are controlled by multiple interacting genes, suggesting that it will be difficult to reduce the partial correlation completely to zero. Ignoring the fact that some sets of SNPs can explain at least part of the correlation between gene expression levels, if not all, might result in missing important clues on the genetic control of gene expression. To enrich the assessment of the causes of correlation between gene expression levels, we develop methods to evaluate whether a set of covariates (e.g. SNPs, or even a set of quantitative expression transcripts) explains at least some of the correlation of gene expression levels. These methods can be used to assist the interpretation of regulation of gene expression and the construction of gene regulatory networks. Copyright © 2008 John Wiley & Sons, Ltd.
A joint back calculation model for the imputation of the date of HIV infection in a prevalent cohort
Authors: Taffé Patrick , May Margaret ,   the Swiss HIV Cohort Study
Published: April 2008

AbstractIn studies of the natural history of HIV‐1 infection, the time scale of primary interest is the time since infection. Unfortunately, this time is very often unknown for HIV infection and using the follow‐up time instead of the time since infection is likely to provide biased results because of onset confounding. Laboratory markers such as the CD4 T‐cell count carry important information concerning disease progression and can be used to predict the unknown date of infection. Previous work on this topic has made use of only one CD4 measurement or based the imputation on incident patients only. However, because of considerable intrinsic variability in CD4 levels and because incident cases are different from prevalent cases, back calculation based on only one CD4 determination per person or on characteristics of the incident sub‐cohort may provide unreliable results. Therefore, we propose a methodology based on the repeated individual CD4 T‐cells marker measurements that use both incident and prevalent cases to impute the unknown date of infection. Our approach uses joint modelling of the time since infection, the CD4 time path and the drop‐out process. This methodology has been applied to estimate the CD4 slope and impute the unknown date of infection in HIV patients from the Swiss HIV Cohort Study. A procedure based on the comparison of different slope estimates is proposed to assess the goodness of fit of the imputation. Results of simulation studies indicated that the imputation procedure worked well, despite the intrinsic high volatility of the CD4 marker. Copyright © 2008 John Wiley & Sons, Ltd.
Comparative effect of melatonin and vitamin E on phenylhydrazine‐induced toxicity in the spleen of Funambulus pennanti
Authors: Sharma Shweta , Haldar Chandana 
Published: April 2008

AbstractPhenylhydrazine (PHZ) oxidation resulting in free iron release followed by free radical generation has increased frequency of cancer. This study aims towards the dose‐dependent response of PHZ and the role of melatonin in comparison with vitamin E following PHZ‐induced toxicity within the lymphoid tissue (spleen) of Indian tropical seasonal breeder, Funambulus pennanti, during reproductively active phase. An increase in the damages in terms of lipid peroxidation (LPO), apoptosis percentage, and splenomegaly was observed following different doses of PHZ treatment, i.e., 0.025, 0.5, and 1 mg/100 g body weight (b.wt.), where dose of 1 mg/100 g b.wt. showed more significant damages. Both melatonin (0.5 mg/100 g b.wt.) and vitamin E (1 mg/100 g b.wt.) administration ameliorated oxidative damages of 1 mg/100 g b.wt. PHZ‐treated group. Melatonin altered PHZ‐induced responses significantly to a greater degree than vitamin E as evidenced by LPO status, SOD activity, and ABTS radical cation scavenging activity of antioxidants. Thus, melatonin might be able to restrict carcinogenic property of PHZ‐induced oxidative stress by protecting macromolecules of the cell from harmful effects of PHZ and instead preserving cell viability. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Investigating the fate of saxitoxins in biologically active water treatment plant filters
Authors: Kayal Nawal , Newcombe Gayle , Ho Lionel 
Published: April 2008

AbstractThe saxitoxins are potent neurotoxins, which can be produced by freshwater cyanobacteria. This study assessed the fate of five saxitoxins variants through biologically active laboratory filters containing media sourced from the filters beds of two water treatment plants (WTPs). Decreases in the concentration of the less toxic variants coincided with increases in the concentrations of the more toxic variants through the filters containing anthracite sourced from two different WTPs. No changes in toxin concentrations were evident through parallel filters containing sand. The results strongly suggest that organisms within the biofilm of the anthracite filters possessed the ability to biotransform the saxitoxins variants, which has important implications for drinking water treatment, particularly since this has the potential to increase the toxicity of the filtered water. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
Genotoxicity of wastewaters used for irrigation of food crops
Authors: Ansari Mohd Ikram , Malik Abdul 
Published: April 2008

AbstractIn most towns of India, wastewater coming from both industrial and domestic sources and without any treatment is used to irrigate the agricultural crops. This practice has been polluting the soil, and pollutants could possibly reach the food chain. For the above reasons, the wastewaters of Ghaziabad City (India), which is used for irrigation, were sampled (at two different sites) and monitored for the presence of genotoxic agents from January 2005 to June 2007. Gas chromatographic analysis showed the presence of certain OC (DDE, DDT, Dieldrin, Aldrin, and Endosulfan) and OP (Dimethoate, Malathion, Methlyparathion, and Chlorpyrifos) pesticides in both the sampling sites. Wastewater samples were concentrated using XAD resins (XAD‐4 and XAD‐8) and liquid–liquid extraction procedures, and the extracts were assayed for genotoxic potential by Ames Salmonella/microsome test, DNA repair defective mutants, and bacteriophage λ systems. The test samples exhibited significant mutagenicity with TA98, TA97a, and TA100 strains with the probable role of contaminating pesticides in the wastewater. However, XAD‐concentrated samples were more mutagenic in both sites as compared to liquid–liquid‐extracted samples. The damage in the DNA repair defective mutants in the presence of XAD‐concentrated water samples were also found to be higher to that of liquid–liquid‐extracted water samples at the dose level of 20 μL/mL culture. All the mutants invariably exhibited significant decline in their colony‐forming units as compared to their isogenic wild‐type counterparts. The survival was decreased by 81.7 and 75.5% in polA− strain in site I, and 76.0 and 73.5% in site II in polA− under the same experimental conditions after 6 h of treatment with XAD‐concentrated and liquid–liquid‐extracted samples, respectively. A significant decrease in the survival of bacteriophage λ was also observed when treated with the test samples. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Hematotoxic and hepatotoxic effects of dichlorvos at sublethal dosages in rats
Authors: Celik Ismail , Yilmaz Zeycan , Turkoglu Vedat 
Published: April 2008

AbstractThe present study was designed to understand the effects of sublethal concentrations of dichlorvos (DIC) on hematological constituent [red blood corpuscles, white blood corpuscles (WBC), mean cell volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelet counts, hemoglobin and hematocrite levels] and serum damage marker enzymes (aspartate aminotransferase, alanin aminotransferase, alkaline phosphatase, and lactate dehydrogenase) in rats at subacute period under laboratory conditions. DIC at dosages of 5 and 10 ppm was administered orally to six male rats ad libitum during the tests for 4 weeks consecutively. According to the results, DIC treatments increased significantly the levels of serum marker enzyme activities, whereas they did not change hematologic constituent except for WBC number treated with both dosages of DIC. The observations presented led us to conclude that the administrations of subacute DIC induced the levels of damage marker enzymes and leukocytosis. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.