bluuebunny/crossref_metadata_2025_split huggingface dataset:
Current distribution in PEM fuel cells. Part 1: Oxygen and fuel flow rate effects
Authors: Natarajan Dilip , Van Nguyen Trung 
Published: June 2005

AbstractA segmented electrode/current collector setup was used to examine the effect of oxygen flow rate, anode sparger temperature, and hydrogen starvation on the spatial and temporal distribution of local current densities along a single gas channel in a PEM fuel cell operated on pure hydrogen and oxygen. Uniformity in local current densities at a given voltage was sustained over longer periods of time with higher oxygen flow rates that enhanced liquid water removal. When water removal rate was not sufficient, electrode flooding occurred in segments that were farthest from the gas inlet. Increasing anode sparger temperature resulted in reduction of water removal rate from the cathode by back diffusion leading to performance reduction of downstream segments. When fuel was in excess, the current density distribution was dominated by the hydration pattern of the membrane electrode assembly. When fuel supply was less than the electrochemical reaction demand, segments furthest from the inlet suffered fuel starvation, resulting in loss of performance. The use of one of the electrode segments as a novel in‐line voltage sensor to reflect available reactant concentrations was also demonstrated. Air operation and effect of cell temperature were also examined and the results are presented in the second part of this series. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Amphiphysin autoimmunity: Paraneoplastic accompaniments
Authors: Pittock Sean J. , Lucchinetti Claudia F. , Parisi Joseph E. , Benarroch Eduardo E. , Mokri Bahram , Stephan Christina L. , Kim Kwang‐Kuk , Kilimann Manfred W. , Lennon Vanda A. 
Published: June 2005

AbstractAmphiphysin‐IgG was identified in 71 patients among 120,000 evaluated serologically for paraneoplastic autoantibodies. Clinical information was available for 63 patients. Cancer was detected in 50 (mostly limited), proven histologically in 46, and was imaged intrathoracically in 4 patients (lung, small–cell [27] and non–small cell [1]), breast [16] and melanoma [2]). Neurological accompaniments included (decreasing frequency): neuropathy, encephalopathy, myelopathy, stiff‐man phenomena, and cerebellar syndrome. In a case examined neuropathologically, parenchymal T‐lymphocyte infiltration (predominantly CD8+) was prominent in lower brainstem, spinal cord, and dorsal root ganglion. Coexisting paraneoplastic autoantibodies, identified in 74% of patients, predicted a common neoplasm and indicated other neuronal autoantigen targets that plausibly explained several neurological manifestations; for example, P/Q‐type Ca2+‐channel antibody with Lambert–Eaton syndrome (n = 5), anti‐neuronal nuclear antibody type 1 with sensory neuronopathy (n = 7), K+‐channel antibody with limbic encephalitis (n = 1) or neuromyotonia (n = 1), and collapsin response‐mediator protein‐5‐IgG with optic neuritis (n = 3). Patients with isolated amphiphysin‐IgG (n = 19) were more likely to be women (with breast cancer, p < 0.05) and to have myelopathy or stiff‐man phenomena (p < 0.01). Overall, a minority of women (39%) and men (12%) had stiff‐man phenomena. Only 10% of women (some with lung carcinoma) and 4% of men fulfilled diagnostic criteria for stiff‐man syndrome. Ann Neurol 2005;58:96–107
Selective vulnerability of preterm white matter to oxidative damage defined by F2‐isoprostanes
Authors: Back Stephen A. , Luo Ning Ling , Mallinson Rebecca A. , O'Malley Jean P. , Wallen Linda D. , Frei Balz , Morrow Jason D. , Petito Carol K. , Roberts Charles T. , Murdoch Geoffrey H. , Montine Thomas J. 
Published: June 2005

AbstractPeriventricular white matter injury (PWMI) is the leading cause of cerebral palsy and chronic neurological disability in survivors of prematurity. Despite the large number of affected children, the pathogenetic mechanisms related to PWMI remain controversial. Through studies of 33 human autopsy brains, we determined that early PWMI was related to oxidative damage that particularly targeted the oligodendrocyte lineage, whereas other neuronal and glial cell types were markedly more resistant. F2‐isoprostanes, an arachidinate metabolite/lipid peroxidation marker of oxidative damage, were significantly increased in early PWMI lesions but not in cerebral cortex. That deleterious lipid peroxidation accompanied early PWMI was supported by similar increases in F2‐isoprostanes levels in the cerebral cortex from term infants with hypoxic‐ischemic cortical injury. Detection of F4‐neuroprostanes, a neuronal‐specific oxidative damage marker, confirmed that neuroaxonal elements were resistant to injury in cerebral cortex and white matter. Significant protein nitration was not detected in PWMI lesions by 3‐nitrotyrosine staining. Significant cellular degeneration was confirmed in early PWMI lesions by terminal deoxynucleotidyltransferase–mediated dUTP nick end labeling and a marked depletion of oligodendrocyte progenitors of 71 ± 8%. Hence, the predilection of preterm infants for PWMI is related to selective lipid peroxidation–mediated injury of cerebral white matter and targeted death of oligodendrocyte progenitors. Ann Neurol 2005;58:108–120
Mental retardation and ataxia due to normotriglyceridemic hypobetalipoproteinemia
Authors: Homer Vivienne M. , George Peter M. , Du Toit Stephen , Davidson James S. , Wilson Callum J. 
Published: June 2005

AbstractA 12‐year‐old boy with mental retardation, obesity, ataxia, and visual impairment was shown to have normal fasting plasma triglyceride but low cholesterol and vitamin E levels. Investigations indicated that he was compound heterozygous for two mutations in the apolipoprotein B gene (APOB), resulting in a failure to express apolipoprotein B‐100, yet retain apolipoprotein B‐48 production. The proband therefore was able to form chylomicrons, but not a low‐density lipoprotein capable of receptor‐mediated endocytosis. This resulted in chronic vitamin E deficiency. We suggest the term normotriglyceridemic hypobetalipoproteinemia for this easily recognizable condition. Ann Neurol 2005;58:160–163
Secondary pneumatization of the maxillary sinus in callitrichid primates: Insights from immunohistochemistry and bone cell distribution
Authors: Smith Timothy D. , Rossie James B. , Cooper Gregory M. , Mooney Mark P. , Siegel Michael I. 
Published: June 2005

AbstractThe paranasal sinuses remain elusive both in terms of function and in the proximate mechanism of their development. The present study sought to describe the maxillary sinuses (MSs) in three species of callitrichid primates at birth, a time when secondary pneumatization occurs rapidly in humans. The MSs were examined in serially sectioned and stained slides from the heads of two Callithrix jacchus, one Leontopithecus rosalia, and two Saguinus geoffroyi. Specimens were examined microscopically regarding the distribution of osteoclasts and osteoblasts along the osseous boundaries of the MS and other parts of the maxillary bone. Selected sections were immunohistochemically evaluated for the distribution of osteopontin (OPN), which facilitates osteoclast binding. Taken together, OPN immunoreactivity and bone cell distribution suggested trends of bone resorption/deposition that were consistent among species for the superior (roof) and inferior (floor) boundaries of the MS. Expansion at the roof and floor of the MS appeared to correspond to overall vertical midfacial growth in callitrichids. Much more variability was noted for the lateral (alveolar) and medial (nasal walls) of the MS. Unlike the other species, the nasal wall of Saguinus was static and mostly composed of inferior portions of the nasal capsule that were undergoing endochondral ossification. The variation seen in the alveolar walls may relate to the presence or absence of adjacent structures, although it was noted that adjacency of deciduous molars influenced medial drift of the alveolar wall in Saguinus but not Leontopithecus. The results of this study are largely consistent with the “structural” or “architectural” hypothesis of sinus formation with respect to vertical MS enlargement, and the variable cellular/OPN distribution found along the nasal and alveolar walls was evocative of Witmer's (J Vert Paleontol 1997;17:1–73) epithelial hypothesis in revealing that most expansion occurred in regions unopposed by adjacent structures. © 2005 Wiley‐Liss, Inc.
Stress and Active Oxygen Species – Effect of α‐Tocopherol on Stress Response
Authors: Tsiakitzis Karyofyllis , Kourounakis Angeliki P. , Tani Ekaterini , Rekka Eleni A. , Kourounakis Panos N. 
Published: June 2005

AbstractStress is implicated in the pathogenesis of numerous disorders such as cardiovascular diseases or neurodegeneration. The extensive overlap between diseases attributed to stress and oxidative damage is indicative of their potential relationship. We hereby study the influence of α‐tocopherol (α‐toc) on the development of stress biomarkers (morphological and biochemical), on specific biomarkers of radical insult (lipid peroxidation, oxidized proteins, or glutathione content in brain and liver), as well as on drug metabolism. In our experimental protocol two groups of female rats are exposed to stress conditions, i.e. cold plus starvation. Before stress and during its application one group is treated with α‐toc for 20 d (0.42 mmol/kg per os, once daily). Our results indicate that oxidative damage accompanies the development of stress, while treatment with α‐toc completely prevents stress‐induced radical attack and reduces stress indices like plasma corticosterone, uropepsinogen, and morphological changes. It is found that stress increases the drug metabolic potential of the liver (total P450, CYP2E1, or CYP3A1 activity). Administration of α‐toc, in combination with stress, further increases erythro mycin N‐demethylation (CYP3A1) compared to stress control, while 4‐nitrophenol hydroxylation (CYP2E1) is not affected significantly.
Evaluation of Antimicrobial Activities of Several Mannich Bases and Their Derivatives
Authors: Gul Halise Inci , Sahin Fikrettin , Gul Mustafa , Ozturk Suzan , Yerdelen Kadir Ozden 
Published: June 2005

AbstractThe aim of this study was to evaluate the antimicrobial activities of several Mannich bases and their derivatives against pathogenic bacteria and fungi. 3‐Dimethylamino‐1‐phenyl‐1‐propanone hydrochloride (Ig1) as mono‐Mannich base, bis(β‐aroylethyl)methylamine hydrochlorides (B1, B5) as bis‐Mannich bases, 3‐aroyl‐4‐aryl‐1‐methyl‐4‐piperidinol hydrochlorides (C1, C5) as piperidinol derivatives, which are structural isomers of bis‐Mannich bases, N,N'‐Bis(3‐dimethylamino‐1‐phenylpropylidene)hydra zine dihydrochlorides (D1) as azine derivative of mono‐Mannich base Ig1, and some representative quaternary derivatives (Ig4 and C6), which are quaternary derivatives of Ig1 and C1, respectively, have been synthesized. Aryl parts were phenyl in B1 and C1, and 2‐thienyl in B5 and C5. Bis‐Mannich bases and quaternary Mannich bases were found to be effective antifungal derivatives. Quaternary mono‐Mannich base Ig4 has shown twice the amount of higher antifungal potency against the human pathogenic fungus Microsporum canis compared with the reference drug amphotericin‐B and it had equal potency against many other fungi species pathogenic in humans and plants. Ig4 was effective against Staphylococcus aureus among the bacteria tested. Preparation of bis‐Mannich bases and qua ternization procedure seemed suitable chemical modifications to prepare effective antifungal compounds. Especially quaternary derivatives Ig4, and to some extent C6, seem to be model compounds to develop new antimicrobial agents for further studies.
Artificial Glycosyl Phosphorylases
Authors: Rousseau Cyril , Ortega‐Caballero Fernando , Nordstrøm Lars Ulrik , Christensen Brian , Petersen Torben Ellebæk , Bols Mikael 
Published: June 2005

Abstractα‐ and β‐Cyclodextrin 6A,6D‐diacids (1 and 2), β‐cyclodextrin‐6‐monoacid (14), β‐cyclodextrin 6A,6D‐di‐O‐sulfate (16) and β‐cyclodextrin‐6‐heptasulfate (19) were synthesised. Acids 1, 2 and 14 were made from perbenzylated α‐ or β‐cyclodextrin, by diisobutylaluminum hydride (DIBAL)‐promoted debenzylation, oxidation and deprotection. Addition of molecular sieves was found to improve the debenzylation reaction. Sulfates 16 and 19 were made by sulfation of the appropriately partially protected derivatives and deprotection. Catalysis of 4‐nitrophenyl glycoside cleavage by these cyclodextrin derivatives was studied. Compounds 1, 2 and 16 were found to catalyse the reaction, with the catalysis following Michaelis–Menten kinetics and depending first order on the phosphate concentration. In a phosphate buffer (0.5 M, 59 °C, pH 8.0), KM varied from 2–10 mM and the kcat/kuncat ratio from 80–1000 depending on the stereochemistry of the substrate and the catalyst, with 2 being the best catalyst and with the sulfated 16 also displaying catalytic ability. The monoacid 14 and the heptasulfate 19 were not catalytic.
Schwann cell behavior after nerve repair by means of tissue‐engineered muscle‐vein combined guides
Authors: Raimondo Stefania , Nicolino Silvia , Tos Pierluigi , Battiston Bruno , Giacobini‐Robecchi Maria G. , Perroteau Isabelle , Geuna Stefano 
Published: June 2005

AbstractSchwann cells play a critical role in peripheral nerve regeneration. When a non‐nervous conduit is used to bridge a nerve defect, the conduit is soon colonized by a number of Schwann cells that make a pathway for regrowing axons. By using electron microscopy, immunohistochemistry, and reverse transcriptase‐polymerase chain reaction analysis, we have investigated the behavior of migratory glial cells along a particular type of autologous tissue‐engineered conduit made of a vein filled with fresh skeletal muscle, using the rat sciatic nerve model. With this particular type of autograft, our data show that many Schwann cells soon take up a close relationship with grafted muscle fibers, and especially with their basal lamina, which appears to serve as a migration pathway for them. The early and massive colonization of the conduit is sustained by both Schwann cell migration and proliferation, as demonstrated by PCNA immunostaining. Later, as they meet regenerating axons, Schwann cells become closely associated with them and eventually lose their connections with grafted muscle fibers because of the formation of perineurial envelopes. Because previous studies showed that α2a‐2b NRG1 is overexpressed at early stages along the muscle‐vein combined tubes, we have also investigated mRNA expression of its two receptors, erbB2 and erbB3. Both messengers are overexpressed, although with different time courses. Overall, our results provide some morphological and biochemical bases for explaining the effectiveness of fresh muscle‐vein combined nerve guides and throw an interesting light on the possible role of α2a‐2b NRG1 through the erbB2/erbB3 heterodimer receptor for nerve regeneration inside non‐nervous conduits. J. Comp. Neurol. 489:249–259, 2005. © 2005 Wiley‐Liss, Inc.
Cortical influences on sizes and rapid plasticity of tactile receptive fields in the dorsal column nuclei
Authors: Wang Xin , Wall John T. 
Published: June 2005

AbstractThe cerebral cortex influences subcortical processing. In the somatosensory system, descending cortical inputs contribute in specific ways to the sizes and plasticity of tactile receptive fields (RFs) in the thalamus, but less is known about cortical influences on these aspects of brainstem RFs. The present studies evaluated how loss of cortical inputs affects sizes and plasticity of RFs in the brainstem dorsal column nuclei (DCN) when peripheral inputs were normal and when peripheral inputs were acutely disrupted. Loss of cortical inputs was produced by acute lesion of somatosensory, motor, and adjacent cortex, whereas disruption of peripheral inputs was produced by cutaneous microinjection of lidocaine (LID). Modest or no changes in sizes of DCN RFs, comparable to changes during control periods of no treatment, were seen in response to cortical lesion. LID caused rapid enlargements in RFs when cortex was intact. LID also caused rapid RF enlargements after cortical lesion, and these enlargements were greater than post‐LID enlargements when cortex was intact. These results indicate that normally sized RFs continue to be produced in the DCN after loss of cortical input. Cortex is also not required for RF enlargements after LID; however, cortical inputs have a constraining effect on these enlargements. Considered with findings from previous thalamic studies, these results suggest that cortical influences on RF size and plasticity in the DCN and thalamus differ in some respects. J. Comp. Neurol. 489:241–248, 2005. © 2005 Wiley‐Liss, Inc.
Generalized approaches to spatial sampling design
Authors: Angulo J. M. , Ruiz‐Medina M. D. , Alonso F. J. , Bueso M. C. 
Published: June 2005

AbstractSpatial sampling design methods are commonly used to select a finite set of locations where observations provide optimal information, under a prescribed criterion, for parameter estimation and spatial inter/extrapolation on the basis of an appropriate statistical model. In some situations, environmental applications may also involve information from soft data. Moreover, the objectives may include the analysis of specific characteristics of interest such as model singularities (e.g. heterogeneity, fractal properties, etc.). The generalized random field theory provides a suitable framework for the formulation and analysis of problems related to these situations. An important case in the geostatistical context is the analysis of intrinsic random fields based on generalized increments. In this article, we formulate the entropy‐based approach to spatial sampling design for random field prediction in a generalized framework, and discuss its potential application in relation to the above aspects. Copyright © 2005 John Wiley & Sons, Ltd.
Effects of socio‐demographic variables on health‐related quality of life determined by the quality of life index—German version
Authors: Prause W. , Saletu B. , Tribl G. G. , Rieder A. , Rosenberger A. , Bolitschek J. , Holzinger B. , Kapfhammer G. , Katschnig H. , Kunze M. , Popovic R. , Graetzhofer E. , Zeitlhofer J. 
Published: June 2005

AbstractStudy objectiveThe purpose of this study was to determine subjective health‐related quality of life (HRQoL) in a sample of the Austrian population over 14 years of age in order to evaluate the effect of socio‐demographic variables on HRQoL.Design/SettingHRQoL was determined by means of the quality of life index ‐ German version (QLI‐Ge). The influence of socio‐demographic variables on HRQoL was assessed by statistical analysis using the Kruskal‐Wallis test and an analysis of variance.ParticipantsA random‐quota procedure was used to get balanced representation from regions and demographic groups of the Austrian population. The sample consisted of 1049 participants, 493 men and 556 women.Main resultsAge was found to influence the QLI‐Ge total score (index score) and most individual items, with increasing age resulting in a decrease in HRQoL. Differences between the sexes were observed in three dimensions: males scored higher in ‘physical well‐being’, ‘psychological well‐being’ and ‘occupational functioning’. Marital status impacted most items with married persons showing better values than divorced persons or singles. Profession had only a minor effect on HRQoL, the level of education showed no influence at all.ConclusionsThe socio‐demographic variables age, sex and objective living conditions had a major influence on subjectively rated HRQoL, whereas profession and education were found to play a minor role in this context. It is recommended that in the interpretation of studies assessing HRQoL the above‐mentioned objective factors be considered. This will be of particular importance when determining the effect of a pharmacotherapy on HRQoL in patients. Copyright © 2005 John Wiley & Sons, Ltd.
Varying Ti‐6Al‐4V surface roughness induces different early morphologic and molecular responses in MG63 osteoblast‐like cells
Authors: Kim H. J. , Kim S. H. , Kim M. S. , Lee E. J. , Oh H. G. , Oh W. M. , Park S. W. , Kim W. J. , Lee G. J. , Choi N. G. , Koh J. T. , Dinh D. B. , Hardin R. R. , Johnson K. , Sylvia V. L. , Schmitz J. P. , Dean D. D. 
Published: June 2005

AbstractOsteoblast response to Ti implants depends not only on the chemistry of the implant but also on the physical properties of the implant surface, such as microtopography and roughness. This study was undertaken to examine early changes in cell morphology and gene expression during the early phase of osteoblast interaction with titanium alloy (Ti‐6Al‐4V) surfaces of two different roughnesses. MG63 osteoblast‐like cells were cultured for 2, 6, 24, and 72 h on smooth (Ra = 0.18 ±0.03 μm) and rough (Ra = 2.95 ±0.23 μm) Ti‐6Al‐4V surfaces. Changes in cell proliferation were assessed by measuring cell number after 72 h in culture. Morphological characteristics were observed by scanning electron microscopy after 2, 6, and 24 h of culture. Changes in gene expression for extracellular signal‐regulated kinase 2 (Erk2), type I collagen (α2[I] collagen), phospholipase C‐γ2 (Plc‐γ2), and β‐actin were measured by RT‐PCR after 6 and 24 h in culture. Cell number was significantly higher on the smooth surface. In scanning electron micrographs, cells on smooth Ti‐6Al‐4V were spherical and raised up from the surface after 2 h in culture. In contrast, cells on the rough surface adopted an irregular, elongated shape that spanned across pits in the surface. At 24 h, cells on the smooth surface had flattened, become elongate, and covered the surface. In contrast, cells on the rough surface appeared more differentiated in shape and the margins of the cells were irregular, with many processes extending out, following the contour of the surface. Of the genes examined, only Erk2 and β‐actin showed a change in expression with surface roughness. Both genes were upregulated (p < 0.05) on the rough surface at 6 h. These results indicate that Ti‐6Al‐4V surface roughness affects osteoblast proliferation, morphology, and gene expression, and that these effects can be measured after periods as short as 2–6 h. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005