bluuebunny/crossref_metadata_2025 huggingface dataset:
The renal vascular response to ANG II injection is reduced in the nonclipped kidney of two-kidney, one-clip hypertension
Authors: Bivol Liliana Monica , Vågnes Øyvind Brune , Iversen Bjarne Magnus
Published: March 2005

The ANG II receptor 1 (AT1R) level in the nonclipped kidney of two-kidney, one-clip hypertension (2K1C) has shown to be unchanged despite a high circulating angiotensin (ANG) II level. To examine the vasoreactive response to ANG II in this kidney, injections of ANG II into renal artery were performed 6 wk after clipping of the kidney and compared with normotensive controls. The renal blood flow (RBF) response to 2.5 ng ANG II was measured by a Transonic transit-time flowmeter, before and after indomethacin and candesartan treatment, and analyzed by a computer program. The RBF response to 5 ng arginine-vasopressin (AVP) was examined for comparison with ANG II. The mRNA for AT1Aand AT1Bas well as Western blotting for AT1R in renal resistance vessels were determined, and plasma renin activity (PRA) was measured. Systolic blood pressure was 183 ± 4 mmHg in 2K1C rats compared with 113 ± 1 mmHg in controls ( P < 0.001). PRA was significantly increased in 2K1C animals ( P < 0.05). Injection of ANG II reduced RBF with 10 ± 2% in the nonclipped kidney and 24 ± 3% in controls ( P < 0.001). After indomethacin, the RBF response increased from 10 ± 2 to 20 ± 3% ( P < 0.02) in 2K1C rats and from 24 ± 3 to 34 ± 6% in controls ( P < 0.01). The doses of candesartan needed to completely inhibit RBF response to ANG II were 30 μg/kg in the nonclipped kidney and 100 μg/kg in controls ( P < 0.001). Western blotting and mRNA for AT1Aand AT1Bin the nonclipped kidney were similar to the controls. The results indicate that despite no difference in total AT1R levels, functional AT1R is downregulated in the nonclipped kidney of 2K1C rats.
A1adenosine receptor knockout mice exhibit increased mortality, renal dysfunction, and hepatic injury in murine septic peritonitis
Authors: Gallos George , Ruyle Thomas D. , Emala Charles W. , Lee H. Thomas
Published: March 2005

Sepsis is a leading cause of multiorgan dysfunction and death in hospitalized patients. Dysregulated inflammatory processes and apoptosis contribute to the pathogenesis of sepsis-induced organ dysfunction and death. A1adenosine receptor (A1AR) activation reduces inflammation and apoptosis after ischemia-reperfusion injury. Therefore, we questioned whether A1AR-mediated reduction of inflammation and apoptosis could improve mortality and organ dysfunction in a murine model of sepsis. A1AR knockout mice (A1knockout) and their wild-type (A1wild-type) littermate controls were subjected to cecal ligation and double puncture (CLP) with a 20-gauge needle. A1knockout mice or A1wild-type mice treated with 1,3-dipropyl-8-cyclopentylxanthine (a selective A1AR antagonist) had a significantly higher mortality rate compared with A1wild-type mice following CLP. Mice lacking endogenous A1ARs demonstrated significant elevations in plasma creatinine, alanine aminotransferase, aspartate aminotransferase, keratinocyte-derived chemokine, and tumor necrosis factor-α 24 h after induction of sepsis compared with wild-type mice. The renal corticomedullary junction from A1knockout mice also exhibited increased myeloperoxidase activity, intercellular adhesion molecule-1 protein, and mRNA encoding proinflammatory cytokines compared with renal samples from A1wild-type littermate controls. No difference in renal tubular apoptosis was detected between A1knockout and A1wild-type mice. We conclude that endogenous A1AR activation confers a protective effect in mice from septic peritonitis primarily by attenuating the hyperacute inflammatory response in sepsis.
Role of Toll-like receptor-4 in genetic susceptibility to lung injury induced by residual oil fly ash
Authors: Cho Hye-Youn , Jedlicka Anne E. , Clarke Robert , Kleeberger Steven R.
Published: March 2005

The mechanisms of susceptibility to particle-induced lung injury are not clearly understood. To evaluate the contribution of genetic background to pulmonary pathogenesis, we compared the lung injury responses to residual oil fly ash (ROFA) in inbred mouse strains and calculated heritability estimates. Significant interstrain (genetic) variation was observed in ROFA-induced lung inflammation and hyperpermeability phenotypes; broad-sense heritability ranged from ∼0.43 to 0.62, and the coefficient of genetic determination ranged from 0.28 to 0.45. C3H/HeJ (HeJ) mice were most resistant to the ROFA-induced injury responses. This was particularly important, as HeJ mice contain a dominant negative mutation in Toll-like receptor-4 ( Tlr4). We then characterized ROFA-induced injury and TLR4 signaling in HeJ mice and its coisogenic strain C3H/HeOuJ (OuJ; Tlr4 normal) to understand the potential role of Tlr4 in this model. ROFA-induced lung injury was significantly greater in OuJ mice compared with HeJ mice. ROFA also significantly enhanced transcript and protein levels of lung TLR4 in OuJ but not in HeJ mice. Greater activation of downstream signal molecules (i.e., MYD88, TRAF6, IRAK-1, NF-κB, MAPK, AP-1) was observed in OuJ mice than in HeJ mice before the development of ROFA-induced pulmonary injury. Putative TLR4-dependent inflammatory genes that were differentially induced by ROFA in the two strains include interleukin-1β and tumor necrosis factor-α. Results support an important contribution of genetic background to particle-mediated lung injury, and Tlr4 is a candidate susceptibility gene.
Respiratory Action of the Intercostal Muscles
Authors: De Troyer André , Kirkwood Peter A. , Wilson Theodore A.
Published: March 2005

The mechanical advantages of the external and internal intercostals depend partly on the orientation of the muscle but mostly on interspace number and the position of the muscle within each interspace. Thus the external intercostals in the dorsal portion of the rostral interspaces have a large inspiratory mechanical advantage, but this advantage decreases ventrally and caudally such that in the ventral portion of the caudal interspaces, it is reversed into an expiratory mechanical advantage. The internal interosseous intercostals in the caudal interspaces also have a large expiratory mechanical advantage, but this advantage decreases cranially and, for the upper interspaces, ventrally as well. The intercartilaginous portion of the internal intercostals (the so-called parasternal intercostals), therefore, has an inspiratory mechanical advantage, whereas the triangularis sterni has a large expiratory mechanical advantage. These rostrocaudal gradients result from the nonuniform coupling between rib displacement and lung expansion, and the dorsoventral gradients result from the three-dimensional configuration of the rib cage. Such topographic differences in mechanical advantage imply that the functions of the muscles during breathing are largely determined by the topographic distributions of neural drive. The distributions of inspiratory and expiratory activity among the muscles are strikingly similar to the distributions of inspiratory and expiratory mechanical advantages, respectively. As a result, the external intercostals and the parasternal intercostals have an inspiratory function during breathing, whereas the internal interosseous intercostals and the triangularis sterni have an expiratory function.
Ghrelin: Structure and Function
Authors: Kojima Masayasu , Kangawa Kenji
Published: March 2005

Small synthetic molecules called growth hormone secretagogues (GHSs) stimulate the release of growth hormone (GH) from the pituitary. They act through the GHS-R, a G protein-coupled receptor whose ligand has only been discovered recently. Using a reverse pharmacology paradigm with a stable cell line expressing GHS-R, we purified an endogenous ligand for GHS-R from rat stomach and named it “ghrelin,” after a word root (“ghre”) in Proto-Indo-European languages meaning “grow.” Ghrelin is a peptide hormone in which the third amino acid, usually a serine but in some species a threonine, is modified by a fatty acid; this modification is essential for ghrelin's activity. The discovery of ghrelin indicates that the release of GH from the pituitary might be regulated not only by hypothalamic GH-releasing hormone, but also by ghrelin derived from the stomach. In addition, ghrelin stimulates appetite by acting on the hypothalamic arcuate nucleus, a region known to control food intake. Ghrelin is orexigenic; it is secreted from the stomach and circulates in the bloodstream under fasting conditions, indicating that it transmits a hunger signal from the periphery to the central nervous system. Taking into account all these activities, ghrelin plays important roles for maintaining GH release and energy homeostasis in vertebrates.
Large Liver Cell Dysplasia in Hepatitis B Virus X Transgenic Mouse Liver and Human Chronic Hepatitis B Virus-Infected Liver
Authors: Koo Ja Seung , Seong Je Kyung , Park Chanil , Yu Dae-Yul , Oh Bong-Kyeong , Oh Seung Hyun , Park Young Nyun
Published: March 2005

Objectives: Large liver cell dysplasia (LCD) is frequently associated with hepatitis B virus (HBV), but it remains uncertain whether it is reactive, senescent or preneoplastic. Methods: The HBX transgenic mice and normal control mice were sacrificed at 1, 3, 5, 7, 9, 11, 13 and 15 months after birth. Twenty-three cases of human B viral chronic hepatitis/cirrhosis with prominent LCD were selected. The immunohistochemical stain of proliferating cell nuclear antigen (PCNA), transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay and senescence-associated β-galactosidase (SA-β-Gal) were evaluated. Results: In HBX transgenic mice, LCD was developed since 3 months and formed small nodules of hepatocellular adenoma, which progressed to hepatocellular carcinoma. The hepatocytes with LCD in HBX transgenic mice showed significantly higher PCNA-labeling index (LI) and lower TUNEL-LI than normal hepatocytes of control mice (p < 0.05). In the majority of human B viral chronic hepatitis/cirrhosis, the hepatocytes with LCD revealed higher PCNA-LI and lower TUNEL-LI than those without, when compared in each case using the same tissue block. SA-β-Gal staining showed no difference between hepatocytes with and without LCD. Conclusion: It is suggested that LCD, related to HBV, might not be just an innocent bystander, but closely related to hepatocarcinogenesis.
How to Predict HCC Development in Patients with Chronic B Viral Liver Disease?
Authors: Han Kwang-Hyub , Ahn Sang Hoon
Published: March 2005

Hepatocellular carcinoma (HCC) is one of the major malignant diseases in Asia. Although no randomized controlled studies have demonstrated decreased mortalities, screening for HCC has become an accepted procedure in the high-risk population. Since the incidence of HCC is strikingly different according to geographical distribution of risk factors, especially chronic hepatitis B virus (HBV) infection, a surveillance strategy in high endemic areas should be established according to national conditions. Chronic necro-inflammation by persistent HBV infection per se can progress to cirrhosis and the occurrence of HCC. As in other chronic liver diseases, the more risk factors the chronic B viral patients have, the higher occurrence of HCC was shown. Based on the risk factors of 4,339 Korean patients, the individual prediction model (IPM) was made by the calculation of relative weighs of risk factors and a self-exploited screening program for HCC was established accordingly. US screening at 6-month intervals was beneficial for the early detection of HCC, especially in the high-risk group, and prolonged survival. The usefulness of a tailored screening program with IPM for HCC was prospectively confirmed. The effective screening system for diagnosis of HCC limited to patients with chronic hepatitis B might be necessitated in high endemic area.
Cross-Reaction of Sera from Patients with Various Infectious Diseases with Leishmania infantum
Authors: Kohanteb Jamshid , Ardehali Sadreddin
Published: March 2005

Objective: To compare and evaluate the application of indirect fluorescent antibody (IFA) and counterimmunoelectrophoresis (CIEP) for laboratory identification of visceral leishmaniasis. Materials and Methods: Serum samples from patients with malaria (Plasmodium vivax, n = 86; Plasmodium falciparum, n = 38), brucellosis (n = 26), tuberculosis (n = 31) and typhoid fever (n = 35) were examined for the presence of antibody to Leishmaniainfantum antigen using IFA and CIEP tests. Results: Using IFA, false-positive results were malaria (P. vivax 19.8%, P. falciparum 13.2%), tuberculosis (6.4%), brucellosis (3.8%), and typhoid fever (2.8%). Using CIEP, a lower percentage of false-positives was observed only among malaria patients (P. vivax 2.3%, P. falciparum 2.6%). Serum samples from patients with other infectious diseases were negative in the CIEP test. Conclusion: Based on the results of this study, the CIEP technique is recommended for immunodiagnosis of visceral leishmaniasis, especially in regions where malaria, brucellosis and tuberculosis are prevalent.
The Impact of Change in Cognitive Functioning and Cognitive Decline on Disability, Well-Being, and the Use of Healthcare Services in Older Persons
Authors: Comijs Hannie C. , Dik Miranda G. , Aartsen Marja J. , Deeg Dorly J.H. , Jonker Cees
Published: March 2005

The study investigated the impact of change in cognitive functioning and cognitive decline on disability, well-being, and the use of healthcare services among older persons in the Longitudinal Aging Study Amsterdam (LASA). Data were collected from 1,349 subjects, aged 65–85 years, who had scores of 24 and higher on the Mini-Mental State Examination (MMSE) at baseline, over a period of 6 years in three waves. The results indicate that cognitive decline and changes in cognitive functioning in older persons who were either not impaired or only mildly cognitively impaired at baseline have an impact on disability, well-being, and the use of healthcare services. With the aging of the population, the number of persons with cognitive impairment is likely to increase, and appropriate services should be available to them.
Nondiffusional Release of Allergens from Pollen Grains of Artemisia vulgaris and Lilium longiflorum Depends Mainly on the Type of the Allergen
Authors: Hoidn Claudia , Puchner Erika , Pertl Heidi , Holztrattner Elisabeth , Obermeyer Gerhard
Published: March 2005

Background: Upon contact with a wet surface, mature pollen grains hydrate and release proteins including allergens. Knowledge of the release mechanism of allergens that are mainly localized intracellularly may allow the design of strategies for inhibition of allergen release and the consequent sensitization process. Methods: An improved pollen chromatography was performed with Artemisia vulgaris and Lilium longiflorum pollen. Using three elution media of different pH, osmolality and salt concentration mimicking various types of wet surfaces, the time-dependent elution profiles of total protein, a cell wall-bound acid phosphatase activity (acPase), allergenic (profilin, Art v 1) and nonallergenic molecules (14-3-3 protein, actin) were monitored. Results: The release kinetics of total protein and cell wall-bound acPase followed an exponential decrease in both pollen species indicating a diffusion-based protein release, whereas the elution profiles of profilin, Art v 1 and 14-3-3 protein showed nondiffusion characteristics. No general dependence on pH, osmolality or salt concentration of the elution media was observable in the elution profiles. Under the applied conditions, actin was not released indicating that the pollen grains remained intact during the elution. Conclusion: The elution profiles of pollen allergens indicated that substantial amounts of these proteins do not diffuse from the cell wall or are released from intracellular compartments during imbibitional leakage. Instead, a mechanism seems to operate that involves translocation from the pollen cytoplasm to the extracellular environment by crossing an intact plasma membrane. Such a mechanism would probably allow the use of pharmaceuticals for inhibition of allergen release.
Roles of Nitric Oxide and Oxidative Stress in the Regulation of Blood Pressure and Renal Function in Prehypertensive Ren-2 Transgenic Rats
Authors: Vaněčková Ivana , Kramer Herbert J. , Novotná Jana , Kazdová Ludmila , Opočenský Martin , Bader Michael , Ganten Detlev , Červenka Luděk
Published: March 2005

Aims: The present study was performed to evaluate the role of nitric oxide (NO) and its interaction with superoxide anion (O2–) in the regulation of blood pressure (BP) and renal function during the developmental phase of hypertension in Ren-2 transgenic rats (TGR). The first aim was to compare BP and renal functional responses to acute NO synthase (NOS) inhibition achieved by intravenous (i.v.) infusion of Nω-nitro-L-arginine-methyl ester (L-NAME) in prehypertensive heterozygous TGR and in transgene-negative Hannover Sprague-Dawley (HanSD) rats. The second aim was to evaluate whether scavenging of O2– by infusion of the superoxide dismutase mimetic tempol increases NO bioavailability which therefore should augment BP and renal functional responses to L-NAME. Methods: Rats were anesthetized, prepared for clearance experiments and BP and renal functional responses were evaluated in response to i.v. L-NAME administration (20 µg·100 g–1·min–1) without or with tempol pretreatment (i.v., 300 µg·100 g–1·min–1). In renal cortical tissue, nitrotyrosine protein expression was assessed by immunoblotting as marker of O2– production and urinary 8-epi-PGF2α excretion as marker of intrarenal oxidative stress was assessed by enzyme immunoassay. Results: BP, glomerular filtration rate (GFR), renal plasma flow (RPF) and sodium excretion were similar in TGR and HanSD. L-NAME infusion induced greater increases in BP in TGR than in HanSD (+42 ± 4 vs. +25 ± 3 mm Hg, p < 0.05). In the absence of a significant change in GFR, L-NAME caused similar decreases in RPF (–32 ± 6 and –25 ± 4%, p < 0.05) in TGR and HanSD. Despite significantly higher renocortical expression of nitrotyrosine and urinary 8-epi-PGF2α excretion in TGR than in HanSD, pretreatment with tempol did not augment the rise in BP and the decrease in RPF induced by L-NAME. Conclusions: The greater BP response to L-NAME in TGR suggests that prehypertensive TGR exhibit an enhanced NO activity in the systemic vasculature as compared with HanSD. Despite increased intrarenal oxidative stress in TGR, the dependency of the intrarenal vascular tone on NO appears to be similar in TGR and HanSD. The lack of a compensatory increase in renal NO activity may partially account for the enhanced renal vascular response to ANG II present in TGR.
Heparin Regulates Transcription of Endothelin-1 Gene in Endothelial Cells
Authors: Kuwahara-Watanabe Kazue , Hidai Chiaki , Ikeda Hiromi , Aoka Yoshikazu , Ichikawa Ken-ichiro , Iguchi Nobuo , Okada-Ohno Masako , Yokota Jinko , Kasanuki Hiroshi , Kawana Masatoshi
Published: March 2005

Heparin, which is widely used as an anticoagulant, has been shown to have antiatherosclerotic and antihypertensive effects in animals and humans. These effects are mediated by the inhibition of endothelin-1 (ET-1) production in endothelial cells. To clarify the mechanism of this inhibition, we investigated the effect of heparin on transcriptional regulation of the ET-1 gene in bovine aortic endothelial cells (BAEC) cultured in fetal calf serum. ET-1 mRNA expression was significantly suppressed by heparin in a dose-dependent manner. Promoter analysis revealed that the minimum ET-1 promoter containing only the GATA and AP-1 sequences as positive cis-acting sites in the ET-1 promoter is sufficient for this suppression. Gel mobility shift assays using oligonucleotides encoding the ET-1 AP-1 and ET-1 GATA sites confirmed that both AP-1 and GATA binding activities in BAEC nuclear extract were markedly inhibited by heparin. Western blot analyses indicated that heparin completely blocked extracellular signal-regulated kinase (ERK) activation, and inhibiting ERK activity resulted in loss of heparin-dependent inhibition of the ET-1 gene. These data indicate that the ET-1 mRNA level is negatively regulated by heparin at the transcription level, through modification of AP-1 and GATA protein binding activities, which direct the ET-1 promoter in BAEC. This effect may be mediated, at least in part, through inhibition of ERK activity.
Renal Disease in Cardiovascular Disorders: An Underrecognized Problem
Authors: Baumelou Alain , Bruckert Eric , Bagnis Corinne , Deray Gilbert
Published: March 2005

Chronic renal disease is generally appreciated as a major and rapidly growing health problem. In the United States alone, as many as 19.5 million people may have markers of early renal disease, and more than 660,000 people are expected to require renal replacement therapy by the year 2010. By contrast, the presence and pathological role of renal disease in patients with cardiovascular disease are somewhat underrecognized. Evidence now shows that even minor impairments in renal function, as indicated by measures including glomerular filtration rate and microalbuminuria, are common in cardiovascular disease states and predictive of cardiovascular events. Indeed, microalbuminuria may be a marker of systemic vascular disease rather than kidney dysfunction alone. In patients with hypertension, diabetes, metabolic syndrome, acute coronary syndromes, and stroke, markers of renal disease have proved to be at least as predictive of morbidity and mortality as conventional risk factors. Yet, chart reviews in a variety of clinical settings reflect poor recognition and management of renal disease in at-risk patients. Models for renal protection are based on the control of risk factors, particularly blood pressure, that are associated with renal and cardiovascular outcomes. Screening protocols for markers of renal disease should recognize the potential inaccuracy of serum creatinine concentrations and the preferability of glomerular filtration rate estimates that take age and gender into account. Pilot programs for screening high-risk populations have shown efficacy in detecting renal disease.
Reduced Cyclooxygenase Involvement in Vascular Endothelial Function in Rat Renal Transplantation
Authors: Smit-van Oosten Annemieke , Boonstra Arnold H. , Navis Gerjan , van Goor Harry , Buikema Hendrik
Published: March 2005

Background: Cardiovascular disease is a major cause of death following renal transplantation. Mechanisms leading to vascular dysfunction outside the transplanted organ involve common risk factors such as hypertension, hypercholesterolemia, proteinuria, but immune-mediated factors may also be involved. We hypothesized that transplantation-associated risk factors are involved in the development of vascular dysfunction following renal transplantation. Methods: Vascular function was studied in Fisher to Lewis allografts. Lewis to Lewis syngrafted rats served as controls. All rats received cyclosporin A for 10 days. Allografts were treated with ACE inhibition or AT1 receptor blockade or left untreated. After 34 weeks, aorta rings were studied for contractile and dilator responses in the presence or absence of L-NMMA and/or indomethacin. Tissue sections were immunostained for COX-1 and COX-2. Results: In contrast to syngrafts and treated allografts, untreated allografts developed proteinuria and hypercholesterolemia. In aortic rings, NOS inhibition similarly increased contractile responses and decreased dilator responses in syngrafts and allografts, indicating comparable NO pathways. In contrast, indomethacin affected contractile and dilator responses in syngrafts, but not in treated and untreated allografts, indicating absence of COX-derived prostanoids in control over vascular tone in allografts. This was in line with immunohistologic analysis demonstrating reduced aortic COX-2 expression in allografts. COX-1 expression was unaltered. Interestingly, RAS blockade quantitatively increased endothelium-dependent dilation without qualitatively altering COX function and expression. Conclusion: Involvement of COX-derived prostaglandins in vascular endothelial function outside the transplanted organ is strongly diminished after allogeneic renal transplantation. RAS blockade improves common cardiovascular risk factors and endothelium-dependent dilation, but fails to restore prostaglandin function.
Tropical Instability Waves as a Resonance between Equatorial Rossby Waves*
Authors: Lyman John M. , Chelton Dudley B. , deSzoeke Roland A. , Samelson Roger M.
Published: March 2005

To understand the characteristics of sea surface height signatures of tropical instability waves (TIWs), a linearized model of the central Pacific Ocean was developed in which the vertical structures of the state variables are projected onto a set of orthogonal baroclinic eigenvectors. In lieu of in situ current measurements with adequate spatial and temporal resolution, the mean current structure used in the model was obtained from the Parallel Ocean Climate Model (POCM). The TIWs in the linear model have cross-equatorial structure and wavenumber–frequency content similar to the TIWs in POCM, even when the vertical structures of the state variables are projected onto only the first two orthogonal baroclinic eigenvectors. Because this model is able to reproduce TIWs with relatively simple vertical structure, it is possible to examine the mechanism for the formation of TIWs. TIWs are shown to form from a resonance between two equatorial Rossby waves as the strength of the background currents is slowly increased.
A Simplified Ice–Ocean Coupled Model for the Antarctic Ice Melt Season
Authors: Ohshima Kay I. , Nihashi Sohey
Published: March 2005

In the Antarctic Ocean, sea ice melts mostly by warming of the ocean mixed layer through heat input (mainly solar radiation) in open water areas. A simplified ice–upper ocean coupled model is proposed in which sea ice melts only by the ocean heat supplied from the air. The model shows that the relationship between ice concentration (i.e., fraction, C) and mixed layer temperature (T) converges asymptotically with time (C–T relationship), which agrees with observed C–T plots during summer in the sector 25°–45°E. This relationship can be used for estimating the bulk heat transfer coefficient between ice and ocean by fitting to observations, and a value of 1.2 × 10−4 m s−1 is obtained. The model shows that the ratio of the heat used for melting to the heat input through open water is inclined to be determined as a function of ice concentration. For typical conditions in the Antarctic ice melt season, the ratio ranges mostly between 0.7 and 0.9. When the model is extended to two dimensions in the meridional direction, with the inclusion of wind forcing, it approximately reproduces the meridional retreat of the Antarctic sea ice. This two-dimensional model can describe the open water–albedo feedback effect, which partly explains the year-to-year variation of the sea-ice retreat in the Antarctic Ocean.
A Refined Quasi-microstructure Model for Finite Element Analysis of Three-dimensional Braided Composites Under Ballistic Penetration
Authors: Gu Bohong , Ding Xin
Published: March 2005

The nondelamination characteristics of three-dimensional (3-D) braided composites under ballistic impact makes them possess considerable potential in ballistic protection applications. However, there are only a few references concerning the calculation of ballistic properties of these composites, and all are based on the continuum assumption of composite materials. In this paper, a refined quasi-microstructure model constructed with crossed inclined laminae of the same braided yarn with the same diameter and fiber volume fraction as in the 3-D braided composite at the actual microstructure level is established to analyze the ballistic penetration of 3-D braided composites target by a rigid projectile. The calculated results of the finite element analysis (FEA) are conservative to estimate the penetration resistance of the composite. From the acceleration-time history of the projectile and the damage morphology of the 3-D braided composite in FEA, it is indicated that the refined quasi-microstructure model can approximately simulate the real ballistic impact damage of these composites. The original ideas of this refined quasi-microstructure model are the scheme of decomposing the 3-D braided composite with the inclined lamina at its actual microstructure level and the adoption of constitutive equations of the reinforced fibers at a high strain rate. This model can also be extended to calculate the ballistic penetration of other 3-D textile preform-reinforced composites by rigid projectiles.
Effect of Fiber Treatments on Mechanical Behavior of Short Fique Fiber-reinforced Polyacetal Composites
Authors: Gañań Piedad , Mondragon Iñaki
Published: March 2005

Different types of natural fiber composites with thermoplastic matrices have been extensively investigated, especially with polyolefins. However, the ability of these fibers as reinforcement of technical matrices has been less studied. This study evaluates the possibilities of using fique fibers (hard fibers) obtained from leaves to reinforce technical matrices such as polyoxymethylene (POM). The mechanical behavior of fique fiber-POM matrix composites has been analyzed as a function of the fiber length, the fiber content, and the surface modification of the fiber. The treatments used correspond to alkalization, and using of formaldehyde, glycidyl methacrylate, and an isocyanate compound. The mechanical properties of these treated fiber composites are higher than those of the untreated ones, due to the enhancement of the fiber-matrix adhesion, observed by the reduction on the hydrophilic tendency of fique fibers. The hydrophilicity has been analyzed by following the variation of the polar component of the free surface energy, calculated by the Owens-Wendt method.
Exploring Complex Transitions: Looking Back at the ‘Golden Age’ of From School to Work
Authors: Goodwin John , O’Connor Henrietta
Published: March 2005

Using data from a little known project, ‘ Adjustment of Young Workers to Work Situations and Adult Roles’, carried out in Leicester between 1962 and 1964, this article aims to re-examine the extent to which transitions during this time were complex, lengthy, non-linear and single-step and explores the assumed linearity and uncomplicated nature of school to work transitions in the 1960s. It is argued that earlier research on youth transitions has tended to understate the level of complexity that characterized youth transitions in the early 1960s and 1970s. Instead, authors exploring transition during this period concentrated on ‘macro’ or more structural issues such as class and gender. It is suggested that transitions in the 1960s were characterized by individual level complexity that has largely been ignored by others exploring school to work transitions.
Seeking Informed Consent: Reflections on Research Practice
Authors: Sin Chih Hoong
Published: March 2005

Researchers should not treat research ethics as pertinent only when conducting particular types of research, with particular types of participants, or at certain points in the research process. This article looks at the issue of securing informed consent where adequate standards and sufficient compliance are revealed to be social constructs. Using the case of a mixed method research project, this article illustrates the demands of securing informed consent when using external agencies as intermediaries; the changing demands on research participants as a result of the scope of research; the different levels of participation required from respondents throughout different phases of the project; and the impossibility of expecting a standard response from all individuals within a research team due to the contingent nature of negotiating and maintaining consent during interviews. The fluidity of consent demands a more reflexive approach to its engagement. Ritualistic adherence to ethical procedures is thus inadequate.
Probabilistic Modeling of Hysteretic Behavior of Elastomers Under 3-D Cyclic Loading
Authors: Scherbakov Maya , Gurvich Mark R.
Published: March 2005

Existing methods to analyze the hysteretic behavior of elasto mers are primarily based on a deterministic point of view, ignoring scatter of material properties. To overcome this limitation, a probabilistic model is proposed to describe random hysteretic energy loss of viscoelastic materials under two- or three-dimensional (2- or 3-D) cyclic loading. The model takes into consideration the random nature of material properties along with a signi ficant nonlinearity of deformation. Simple analytical solutions to predict major statistical characteristics of random energy loss (mean values, standard deviations) are offered. A generalization of the 3-D model is proposed, where cyclic functions of loading may be different in different directions. A problem of experimental characterization of random material properties is systematically considered on examples of two representative elastomers.
Effects of Minimum Wage Legislation
Authors: Morris David , Collier Tamsin , Wood Geoff
Published: March 2005

This article explores the consequences of minimum wage legislation on small businesses, focusing specifically on the case of the equestrian sector in the UK. This was done by means of a survey of employers, rather than trying to discern impacts from existing national survey data. The survey revealed that, contrary to conventional wisdom regarding the negative effects of minimum wages on smaller firms, a sizeable proportion of respondents were favourably inclined to such measures. This would reflect the diversity of the small business sector, and highlights the need for further research in this area.
Regarding the Noun ‭ףרש‬ in the Hebrew Bible
Authors: Provençal Philippe
Published: March 2005

The semantic value of the Classical Hebrew noun ‭ףרש‬ ( śārāp) is analysed by comparing the information found in the textual witnesses in the Hebrew Bible with archaeological, historical and zoological data. This analysisconfirms that the word means ‘cobra’ in Classical Hebrew, as both the mythological use in the Bible and the iconographic data from archaeological material from the Levant fit together with the zoological data regarding cobras. The understanding found in ancient translations, i.e. the Septuagint, the Vulgate and Peshitta, together with the way desert snakes are designated by Bedouin in the Sinai in recent times, are drawn in to further strengthenthis identification.
The Double Redaction of the Deuteronomistic History: The Case is Still Compelling
Authors: Nelson Richard
Published: March 2005

This article argues that the Deuteronomistic History (DH) was first composed during the reign of Josiah and then revised by the addition of limitedamounts of more pessimistic material in the early exile. The argument ofintense thematic dissonance is supported by a number of confirmatory observations. The interests of DH are pre-exilic and culminate in the reforms of Josiah. Many signals indicate a change of authorship near theend of 2 Kings. Recognizing the fact of double redaction leads to a proper understanding of the purpose and theology of DH.
The Analysis of Elasto-plastic Stresses in the Composite Laminate with a Circular Hole Subjected to In-plane Loads by Means of Finite Element Method
Authors: Ozbay Mahmut , Ozer Dilek
Published: March 2005

In this study, the analysis of the elastic and elasto-plastic stresses on the cross section of a composite laminate with circular hole subjected to in-plane loads is performed. The laminate with a circular hole is subjected to a uniform axial planar load along one edge where no load is exerted along the hole edge. Aluminum metal-matrix composite laminate is composed of four orthotropic plates oriented with different angles in the symmetric and anti-symmetric manner. The elastic and elastoplastic stresses are analyzed with the Finite Element Method (FEM) by means of a program developed with FORTRAN. By the end of the analysis the retained stresses due to yield of the composite laminate are evaluated and the results of the applications are compared.
Investigation of Stress Analysis and Shear Correction Factors In A Thermoplastic Composite Cantilever Beam Under In-plane Loading
Authors: Okumus Fuat
Published: March 2005

In the present study, an analysis of stresses and shear correction factors are carried out for a homogeneous polyethylene thermoplastic cantilever beam which is reinforced by steel fibers and whose cross section is rectangular. The beam exhibits in-plane shear deformation by an applied shear force and there exists the effect of extension-shear coupling which does not exist in out-of-plane shear deformation. The shear correction factor is defined taking into account the coupling effect. The distributions of normal stress, shear stress, and shear strain across the cross section of the rectangular solid beam are obtained analytically. In order to verify the analytical solution results were compared with the finite element method. A rectangular element with nine nodes has been choosen. A composite plate is meshed into 48 elements and 228 nodes with simply supported and in-plane loading conditions. Predictions of the stress distributions of the beam using finite elements were overall in good agreement with analytical values. The variation of shear correction factors for the composite beam is also investigated with the change of ply angles.
Tensile, Flexural, and Chemical Resistance Properties of Waste Silk Fabric-reinforced Epoxy Laminates
Authors: Priya S. Padma , Ramakrishna H. V. , Rai S. K. , Rajulu A. Varada
Published: March 2005

Waste silk fabric-reinforced epoxy laminates were developed with varying content of silk fabric. The mechanical properties like tensile strength and flexural strength of the composites were determined. These properties were found to increase with silk fabric content. These composites also showed good chemical resistance to some acids, alkalies, and solvents. The interfacial bonding between the reinforcement and the matrix was examined using SEM technique.
Dynamic Caustic Analysis of Propagating Mode II Cracks in Transversely Isotropic Material
Authors: Yao Xue-Feng , Zhao Hong-Ping , Yeh Hsien-Yang
Published: March 2005

Dynamic stress singularities of the Mode II propagating crack tip in transversely isotropic media are analyzed numerically by the reflection optical method of caustics. Parametric equations of dynamic caustics and their respective initial curves for moving crack tip are established by introducing appropriate scaling coordinate. Theoretical caustics and the initial curves for different relative crack velocity are simulated. The influences of crack velocity and stress intensity factor on the size and shape of caustics and initial curves are analyzed. Dynamic Mode II SIFs of propagating tip are evaluated by the maximum longitudinal distance of the caustics and the correction factors with velocity effects.
Heavy metal content of combustible municipal solid waste in Denmark
Authors: Riber Christian , Fredriksen Gry S. , Christensen Thomas H.
Published: March 2005

Data on the heavy metal composition of outlets from Danish incinerators was used to estimate the concentration of Zn, Cu, Pb, Cr, Ni, Cd, As and Hg in combustible waste (wet as received) at 14 Danish incinerators, representing about 80% of the waste incinerated in Denmark. Zn (1020 mg kg-1), Cu (620 mg kg-1) and Pb (370 mg kg-1) showed the highest concentration, whereas Hg (0.6 mg kg-1) showed the lowest concentration. The variation among the incinerators was in most cases within a factor of two to three, except for Cr that in two cases showed unexplained high concentrations. The fact that the data represent many incinerators and, in several cases, observations from a period of 4 to 5 years provides a good statistical basis for evaluating the content of heavy metals in combustible Danish waste. Such data may be used for identifying incinerators receiving waste with high concentrations of heavy metals suggesting the introduction of source control, or, if repeated in time, the data must also be used for monitoring the impacts of national regulation controlling heavy metals. It is recommended that future investigations consider the use of sample digestion methods that ensure complete digestion in order to use the data for determining the total heavy metal content of waste.
Dynamic modelling of packaging material flow systems
Authors: Tsiliyannis Christos A.
Published: March 2005

A dynamic model has been developed for reused and recycled packaging material flows. It allows a rigorous description of the flows and stocks during the transition to new targets imposed by legislation, product demand variations or even by variations in consumer discard behaviour. Given the annual reuse and recycle frequency and packaging lifetime, the model determines all packaging flows (e.g., consumption and reuse) and variables through which environmental policy is formulated, such as recycling, waste and reuse rates and it identifies the minimum number of variables to be surveyed for complete packaging flow monitoring. Simulation of the transition to the new flow conditions is given for flows of packaging materials in Greece, based on 1995-1998 field inventory and statistical data.
Nickel recovery from spent nickel catalyst
Authors: Sahu Kamala K. , Agarwal Archana , Pandey Banshi D.
Published: March 2005

A process for nickel recovery from a spent catalyst of definite composition has been developed using the hydro-metallurgical route. The processing steps includes direct sulphuric acid leaching followed by separation of iron as well as silica and other impurities. For a 152 μm particle size catalyst, extraction of about 98% nickel was achieved at 363 K in 2 h using a sulphuric acid concentration (v/v) of 8% and a pulp density of 10%. The dissolution of nickel followed diffusion-controlled leaching kinetics. Increase in temperature and sulphuric acid concentration resulted in increase in the nickel recovery. The activation energy for nickel dissolution was calculated to be 62.8 kJ mol-1. Finally, nickel was recovered as value-added products such as sulphide and oxalate with overall recovery of 90 and 88% of nickel, respectively.
Nitrous oxide (N2O) emissions from waste and biomass to energy plants
Authors: Gutierrez Maria Jose Fernandez , Baxter David , Hunter Christopher , Svoboda Karel
Published: March 2005

Following the Kyoto protocol with respect to reducing emissions of greenhouse gases emissions, and EU energy policy and sustainability in waste management, there has been an increased interest in the reduction of emissions from waste disposal operations. From the point of view of nitrous oxide (N2O) emissions, waste incineration and waste co-combustion are very acceptable methods for waste disposal. In order to achieve very low N2O emissions from waste incineration, particularly for waste with higher nitrogen content (e.g. sewage sludge), two factors are important: temperature of incineration over 900°C and avoiding the selective non-catalytic reduction (SNCR) de-NOX method based on urea or ammonia treatments. The more modern selective catalytic reduction (SCR) systems for de-NOX give rise to negligible sources of N2O.
Chemical and microbiological stability of waste sludge from paper industry intended for brick production
Authors: Cernec Franc , Zule Janja , Moze Adolf , Ivanuš Alenka
Published: March 2005

Due to its chemical composition, waste sludge generated in the paper industry may be used as a raw material for brick production. Brick manufacture is limited to the warmer months of the year whereas sludge is produced continuously by different effluent treatment devices. Therefore, it has to be stored until further processing. For this reason, it is essential that it is not subject to significant chemical and microbiological decomposition during storage. In the experiment, sludge from a tissue paper mill was tested for its stability. It was stored for several weeks during winter and summer periods in a pile, 2 m in height, in an open but covered store. Different leachable organic and inorganic compounds indicating possible ongoing deterioration processes, as well as pH value, redox potential, temperature, humidity and dry matter content were evaluated weekly in water extracts of homogenized sludge samples. According to the test results, the material may be considered to be chemically and microbiologically stable as there was practically no emission of odorous and toxic compounds such as H2S, NH3 and butyric acid despite prolonged storage times and elevated environmental temperatures. All the microbial species identified in the sludge during storage belong to the typical microflora of the environment.
Synthesis and Characterization of Polyamide of Trans-4-hydroxy-L-proline used as Porogen Filler in Acrylic Bone Cement
Authors: Puska Mervi , Yli-Urpo Antti , Vallittu Pekka , Airola Karri
Published: March 2005

The aim of this study was to synthesize on a larger scale, an experimental polyamide based on an amino acid of trans-4-hydroxy-L-proline. The polyamide of trans-4-hydroxy-L-proline has been used as porogen filler (i.e., a hydrophilic pore generating material) in nondegradable acrylic bone cement. In in vitro studies, this hydrophilic filling component has been shown to form porosity within the acrylic bone cement in an aqueous environment. The formation of in situ porosity in the acrylic polymer matrix is believed to improve the fixation between the cement and the living bone. Namely, a porous structure can support bone ingrowth and strengthen the mechanical connection between the acrylic bone cement and the bone. The monomer, trans-4-hydroxy-L-proline methyl ester, was prepared from trans-4-hydroxy-L-proline by means of two steps, and the monomer was then polymerized to polyamide of trans-4-hydroxy-L-proline. The polymerization was carried out using a melt polycondensation method. The molecular weights (Mψ) of the produced polyamides were between 1800 and 3600. The products were characterized by FTIR and 1H-NMR spectroscopy.
Acculturation and Reported Intimate Partner Violence Among Latinas in Los Angeles
Authors: Garcia Lorena , Hurwitz Eric L. , Kraus Jess F.
Published: March 2005

This study sought to understand the relationship between acculturation and reporting intimate partner violence (IPV) among Latinas. A cross-sectional interviewer-administered survey was conducted at public health care clinics throughout Los Angeles County. Logistic regression was used to estimate the effect of acculturation on reporting IPV. An increasing trend of reporting IPV was observed among Latinas who were more acculturated (chi-square = 41.02, p = .0006). Highly acculturated Latinas were more likely to report IPV compared with least acculturated Latinas (prevalence odds ration = 2.18, 95% confidence level = 0.98, 4.89) and moderately acculturated Latinas were more likely to report IPV compared with least acculturated Latinas (prevalence odds ration = 1.29, 95% confidence level = 0.69, 2.43). Culturally competent IPV prevention programs may be the key to significantly reducing the number of women exposed to this serious public health problem.