bluuebunny/crossref_metadata_2025_split huggingface dataset:
First‐principle studies of intermolecular and intramolecular catalysis of protonated cocaine
Authors: Zhan Chang‐Guo , Deng Shi‐Xian , Skiba Jaime G. , Hayes Beth A. , Tschampel Sarah M. , Shields George C. , Landry Donald W. 
Published: May 2005

AbstractWe have performed a series of first‐principles electronic structure calculations to examine the reaction pathways and the corresponding free energy barriers for the ester hydrolysis of protonated cocaine in its chair and boat conformations. The calculated free energy barriers for the benzoyl ester hydrolysis of protonated chair cocaine are close to the corresponding barriers calculated for the benzoyl ester hydrolysis of neutral cocaine. However, the free energy barrier calculated for the methyl ester hydrolysis of protonated cocaine in its chair conformation is significantly lower than for the methyl ester hydrolysis of neutral cocaine and for the dominant pathway of the benzoyl ester hydrolysis of protonated cocaine. The significant decrease of the free energy barrier, ∼4 kcal/mol, is attributed to the intramolecular acid catalysis of the methyl ester hydrolysis of protonated cocaine, because the transition state structure is stabilized by the strong hydrogen bond between the carbonyl oxygen of the methyl ester moiety and the protonated tropane N. The relative magnitudes of the free energy barriers calculated for different pathways of the ester hydrolysis of protonated chair cocaine are consistent with the experimental kinetic data for cocaine hydrolysis under physiologic conditions. Similar intramolecular acid catalysis also occurs for the benzoyl ester hydrolysis of (protonated) boat cocaine in the physiologic condition, although the contribution of the intramolecular hydrogen bonding to transition state stabilization is negligible. Nonetheless, the predictability of the intramolecular hydrogen bonding could be useful in generating antibody‐based catalysts that recruit cocaine to the boat conformation and an analog that elicited antibodies to approximate the protonated tropane N and the benzoyl O more closely than the natural boat conformer might increase the contribution from hydrogen bonding. Such a stable analog of the transition state for intramolecular catalysis of cocaine benzoyl‐ester hydrolysis was synthesized and used to successfully elicit a number of anticocaine catalytic antibodies. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 980–986, 2005
Thr 446 phosphorylation of PKR by HCV core protein deregulates G2/M phase in HCC cells
Authors: Alisi A. , Mele R. , Spaziani A. , Tavolaro S. , Palescandolo E. , Balsano C. 
Published: May 2005

AbstractHepatitis C virus (HCV) is the major causative viral agent of cirrhosis and hepatocarcinoma (HCC). HCV core protein affects cell homeostasis, playing an important role in viral pathogenesis of HCC. We investigate the effects of HCV core protein expression on cell growth in HCC cell lines. Cell cycle distribution analysis of HepG2 polyclonal core positive cells reveals a peculiar accumulation of cells in G2/M phase. Different pathways mediate G2/M arrest: such as p53 and double strand RNA protein kinase (PKR). Flow cytometry in p53‐null cells demonstrates that p53 plays only a marginal role in inducing HCV core‐dependent G2/M phase accumulation that seems to be significantly affected by the functional inactivation of PKR. HCC core positive cells are characterized by a significant PKR phosphorylation in Thr 446 residue, which leads deregulation of mitosis. Moreover, we observe that the overexpression of the viral protein induces an upregulation of PKR activity, which does not correlate with an increased eIF‐2 phosphorylation. This uncommon behavior of PKR suggests that its activation by HCV core protein could involve alternative PKR‐dependent pathways, implicated in core‐dependent G2/M accumulation. The described biological effects of HCV core protein on cell cycle could be an additional viral mechanism for both HCV resistance to interferon (IFN) and HCC HCV‐related pathogenesis. © 2005 Wiley‐Liss, Inc.
Inhibition of colon cancer cell proliferation by the dietary compound conjugated linoleic acid is mediated by the CDK inhibitor p21CIP1/WAF1
Authors: Lim Do Y. , Tyner Angela L. , Park Jae‐Bong , Lee Jae‐Yong , Choi Yung H. , Park Jung H.Y. 
Published: May 2005

AbstractOur previous studies indicated that dietary conjugated linoleic acid (CLA) inhibits colon tumor cell proliferation in vitro and in vivo. To identify mechanisms by which CLA regulates growth arrest, the HT‐29 human colon carcinoma cell line was treated with various physiological concentrations of CLA and analyzed by flow cytometry. We detected a dose‐dependent increase in the percentage of cells arrested in G1 after CLA treatment that was accompanied by induction of the cyclin dependent kinase (CDK) inhibitor p21CIP1/WAF. CLA addition also led to increased p21 expression in HCT116 and SW480 cells, indicating that p21 induction is a general consequence of CLA treatment in colon cancer cells. Since both HT‐29 and SW480 cells have mutant p53, our data indicate that p53 is not essential for induction of p21. In addition to an increase in p21 levels, HT‐29 cell growth arrest was also accompanied by moderate decreases in Cyclin A, D1, E, and proliferating cell nuclear antigen (PCNA) levels. Following CLA treatment, p21 associated with and inhibited CDK4 and CDK2, and this correlated with reduced phosphorylation of retinoblastoma proteins. Increased association of p21 with PCNA was also detected. Dietary CLA inhibits cell cycle progression by inducing p21, which negatively regulates the growth promoting activities of CDK/cyclins and PCNA. These studies indicate that physiological concentrations of CLA inhibit growth of colon cancer cells with either wild‐type or mutant p53, and may have therapeutic benefits in vivo. © 2005 Wiley‐Liss, Inc.
Intrinsic excitability, synaptic potentials, and short‐term plasticity in human epileptic neocortex
Authors: Koch Uwe‐Robert , Mußhoff Ulrich , Pannek Heinz‐Wolfgang , Ebner Alois , Wolf Peter , Speckmann Erwin‐Josef , Köhling Rüdiger 
Published: May 2005

AbstractAlthough studies of epileptic human hippocampus suggest changes of synaptic and intrinsic excitability, few changes, save the appearance of spontaneous field/synaptic potentials, are known in epileptic neocortical tissue. However, invasive EEG and histological studies suggest that neocortical tissue, even in mesial temporal lobe epilepsy, can play an important role as an irritative zone or extrahippocampal focus. We hypothesized that intrinsic neuronal and synaptic excitability, as well as short‐term plasticity, are altered in neocortical areas, particularly with elevated K+ levels as occur during seizures. We analyzed neuronal firing properties, synaptic responses, and paired‐pulse plasticity in human neocortical slices from tissue resected during epilepsy surgery, both under normal and under pathological conditions, i.e., after elevating K+ (4/8 mM), with rat neocortical slices as controls. Neuronal firing properties were not different. We did find, however, alterations of synaptic responsiveness in epileptic tissue, i.e., an elevated network excitability with K+ elevations, and reduction of paired‐pulse depression. © 2005 Wiley‐Liss, Inc.
Astrocytes protect neurons from ethanol‐induced oxidative stress and apoptotic death
Authors: Watts Lora Talley , Rathinam Mary Latha , Schenker Steven , Henderson George I. 
Published: May 2005

AbstractEthanol induces oxidative stress in cultured fetal rat cortical neurons and this is followed by apoptotic death, which can be prevented by normalization of cell content of reduced glutathione (GSH). Because astrocytes can play a central role in maintenance of neuron GSH homeostasis, the following experiments utilized cocultures of neonatal rat cortical astrocytes and fetal cortical neurons to determine if astrocytes could protect neurons from ethanol‐mediated apoptotic death via this mechanism. In cortical neurons cultured in the absence of astrocytes, ethanol (2.5 and 4 mg/ml; 6‐, 12‐, and 24‐hr exposures) decreased trypan blue exclusion and the MTT viability measures by up to 45% (P < 0.05), increased levels of reactive oxygen species (ROS) by up to 81% (P < 0.05), and decreased GSH within 1 hr of treatment by 49 and 51% for 2.5 and 4 mg/ml, respectively (P < 0.05). This was followed by onset of apoptotic cell death as determined by increased Annexin V binding and DNA fragmentation by 12 hr of ethanol exposure. Coculturing neurons with astrocytes prevented GSH depletion by 2.5 mg/ml ethanol, whereas GSH content was increased over controls in neurons exposed to 4 mg/ml ethanol (by up to 341%; P < 0.05). Ethanol generated increases in neuron ROS and apoptosis; decreases in viability were also prevented by coculture. Astrocytes were largely insensitive to ethanol, using the same measures. Only exposure to 4.0 mg/ml ethanol decreased GSH content in astrocytes, concomitant with a 204% increase in GSH efflux (P < 0.05). These studies illustrate that astrocytes can protect neurons from ethanol‐mediated apoptotic death and that this may be related to maintenance of neuron GSH. © 2005 Wiley‐Liss, Inc.
Effect of soybean addition on the rheological properties and breadmaking quality of wheat flour
Authors: Ribotta Pablo D , Arnulphi Sebastián A , León Alberto E , Añón María C 
Published: May 2005

AbstractThe effects of enzyme‐active full‐fat (EAFFSF), heat‐treated full‐fat (HTFFSF) and enzyme‐active defatted (EADSF) soy flours and commercial soy protein isolates (SPIs) on mixing properties and extensibility of dough, gluten formation, gas production and retention properties of dough and bread quality were studied. The soy products utilised in this study presented values of urease activity, nitrogen solubility index (NSI) and enthalpies of protein denaturation according to their previous heat processing. Soy products interfered in gluten formation, weakened dough strength and decreased dough gas retention capacity. Bread quality was negatively affected by soy product addition. The negative effects were exacerbated by an increase in soy/wheat ratio. Soybean protein state was identified as an important factor in determining dough and bread properties. Copyright © 2005 Society of Chemical Industry
Effect of saponins on the foam/flow properties of paste and physical characteristics of akara made from decorticated black‐eyed cowpeas
Authors: Park Jin‐Young , Plahar Minerva A , Hung Yen‐Con , McWatters Kay H , Eun Jong‐Bang 
Published: May 2005

AbstractAkara, a deep‐fat‐fried cowpea paste product, is a popular snack food in West Africa. Foaming capacity of the cowpea paste is important for achieving a spongy light‐textured fried product. The effect of two saponins, Yucca and Quillaja, on the foaming capacity of cowpea paste was investigated. Results showed that an increase in the amount of saponin added (1, 2, 4%) resulted in a decrease in specific gravity and apparent viscosity of the cowpea paste. Addition of saponin also significantly reduced the firmness and increased the cohesiveness of the akara compared with the control. Akara made using the Quillaja saponin was less firm and more cohesive than akara made using the Yucca saponin. An increase in the amount of saponin added to the cowpea paste resulted in a darker (lower L*) and browner colour of akara. However, akara containing 1% Yucca saponin had similar colour attributes to the control but was less firm and more cohesive. Copyright © 2005 Society of Chemical Industry
Amplification and overexpression of Aurora kinase A (AURKA) in immortalized human ovarian epithelial (HOSE) cells
Authors: Chung C.M. , Man C. , Jin Y. , Jin C. , Guan X.Y. , Wang Q. , Wan T.S.K. , Cheung A.L.M. , Tsao S.W. 
Published: May 2005

AbstractImmortalization is an early and essential step of human carcinogenesis. Amplification of chromosome 20q has been shown to be a common event in immortalized cells and cancers. We have previously reported that gain and amplification of chromosome 20q is a non‐random and common event in immortalized human ovarian surface epithelial (HOSE) cells. The chromosome 20q harbors genes including TGIF2 (20q11.2‐q12), AIB1 (20q12), PTPN1 (20q13.1), ZNF217 (20q13.2), and AURKA (20q13.2‐q13.3), which were previously reported to be amplified and overexpressed in ovarian cancers. Some of these genes may be involved in immortalization of HOSE cells and represent crucial premalignant changes in ovarian surface epithelium. Investigation of the involvement of these genes was examined in four pairs of pre‐crisis (preimmortalized) and post‐crisis (immortalized) HOSE cells. Overexpression of AURKA (Aurora kinase A), also known as BTAK and STK15, by both real time‐quantitative polymerase chain reaction (RT‐QPCR) and Western blotting was detected in all the four immortalized HOSE cells examined while overexpression of AIB1 and ZNF217 was observed in two of four immortalized HOSE cells examined. Overexpression of TGIF2 and PTPN1 was not significant in our immortalized HOSE cell systems. The degree of overexpression of AURKA was shown to be closely associated with the amplification of chromosome 20q in immortalized HOSE cells. Fluorescence in situ hybridization (FISH) with labeled P1 artificial clone (PAC) confirmed the amplification of the chromosomal region (20q13.2‐13.3) where AURKA resides. DNA amplification of AURKA was also confirmed using semi‐quantitative PCR. Our study showed that amplification and overexpression of AURKA is a common and significant event during immortalization of HOSE cells and may represent an important premalignant change in ovarian carcinogenesis. © 2005 Wiley‐Liss, Inc.
Facioscapulohumeral dystrophy presenting as infantile facial diplegia and late‐onset limb‐girdle myopathy in members of the same family
Authors: Felice Kevin J. , Jones Jennifer M. , Conway Stephen R. 
Published: May 2005

AbstractWe report a family with markedly variable myopathic weakness due to facioscapulohumeral muscular dystrophy (FSHD). The proband developed mild late‐onset proximal limb weakness. Her two daughters had severe infantile facial diplegia, initially diagnosed as Möbius syndrome, and mild childhood‐onset limb weakness and scapular winging. Results of facial muscle electromyography and muscle histopathology supported a myopathic disorder. This case study further highlights the broad clinical spectrum and intrafamily variability in FSHD, and the occasional absence of a positive correlation between fragment size and disease onset. Moreover, this study underscores the importance of considering FSHD in cases of infantile facial diplegia, especially in patients not demonstrating the full clinical features of Möbius syndrome. In difficult cases, facial muscle electromyography may help to differentiate myopathic from neuropathic weakness, and help guide further diagnostic studies. Muscle Nerve, 2005
Model reduction by constraints, discretization of flow problems and an induced pressure stabilization
Authors: Layton W. 
Published: May 2005

AbstractFor flow problems, turbulence models and numerical methods can be thought of as model reductions. Herein we consider reduction imposed as a constraint using Lagrange multipliers. Development of this last method recovers the subgrid eddy viscosity method and a new stabilization of the incompressibilty constraint. Analysis of the new incompressibility stabilization reveals that stabilization is only really needed for the finest pressure scales. Copyright © 2005 John Wiley & Sons, Ltd.
Ab initiostudy of the effect of α‐substituents on the acidity of cyclopropabenzene
Authors: Eckert‐Maksić Mirjana , Glasovac Zoran 
Published: May 2005

AbstractThe effect of substituents directly bound to the deprotonation site (C‐7) on the acidity of cyclopropabenzene was studied using the MP2/6–31+G* method. The studied substituents encompass a variety of π‐ and σ‐accepting groups including the highly electronegative fluorine atom. It is shown that all substituents enhance the acidity of cyclopropabenzene with the effect being the smallest (0.02 kcal mol−1) for the methyl group and the largest (33.7 kcal mol−1) for the hydrosulfonyl group. It is further shown that the α‐subsituents employed stabilize the cyclopropabenzenyl anion less efficiently than the cyclopropenyl anion, with the effect being more pronounced for the substituents acting via inductive/field effects. This is attributed to the fact that attachment of inductively/field acting substituents to the carbanionic site predominantly stabilize the cyclopropenyl anion by increasing the s character of the lone pair, diminishing the antiaromatic character of the three‐membered ring at the same time. Hence these two effects are operative in concert. The opposite occurs in related cyclopropabenzenyl anions. Here, the rehybridization at the carbanionic center does stabilize the lone pair, but decreases the anionic resonance of the whole system, because of a decrease in overlap between the lone pair and the π‐AO of the annelated bond. The reverse picture holds for the conjugatively acting substituents. Copyright © 2005 John Wiley & Sons, Ltd.
Continuous precipitation polymerization of acrylic acid in supercritical carbon dioxide: The polymerization rate and the polymer molecular weight
Authors: Liu Tao , DeSimone Joseph M. , Roberts George W. 
Published: May 2005

AbstractThe precipitation polymerization of acrylic acid in supercritical carbon dioxide was studied in a continuous stirred tank reactor with 2,2′‐azobis(2,4‐dimethylvaleronitrile) as the free‐radical initiator. The reactor temperature was between 50 and 90 °C, the pressure was 207 bar, and the average residence time was between 12 and 40 min. The product polymer was a white, dry, fine powder that dissolved in water. A wide range of polymer molecular weights (5–200 kg/mol) was obtained. The effects of the operating variables on the polymerization rate and on the polymer molecular weight were evaluated. The observed kinetics suggested that polymerization took place in both the supercritical fluid and the precipitated polymer particles. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2546–2555, 2005
Minimal access therapy in pediatric pulmonary hydatid cysts
Authors: Tullu Milind S. , Lahiri Keya R. , Kumar Sarita , Oak Sanjay N. 
Published: May 2005

AbstractHydatid cysts occur commonly in lungs in the pediatric age group. Though medical management has been tried, definitive management of the condition is essentially surgical. Use of video‐assisted thoracic surgery (VATS) has been rarely employed for the management of pulmonary hydatid cysts. We present a 10‐year‐old boy with pulmonary hydatid cysts treated with VATS‐assisted minithoracotomy with hydatid cyst enucleation and capitonnage. The patient developed a lung abscess postoperatively and had to undergo lobectomy. The surgical management of pulmonary hydatid cysts is discussed here. The role of minimal access therapy for pulmonary hydatid cysts is highlighted. © 2005 Wiley‐Liss, Inc.
In vivo metabolic fate of [14C]‐acetamiprid in six biological compartments of the honeybee, Apis mellifera L
Authors: Brunet Jean‐Luc , Badiou Alexandra , Belzunces Luc P 
Published: May 2005

AbstractThe in vivo metabolism of acetamiprid was studied in the honeybee, Apis mellifera L. The distribution of acetamiprid and its metabolites was monitored over a 72‐h period in six biological compartments: head, thorax, abdomen, haemolymph, midgut and rectum. Honeybees were treated orally with 100 µg [14C]‐acetamiprid kg−1 bee, a dose which is about 1500 times lower than the median lethal dose. After 72 h, only 40% of the total radioactivity was eliminated, suggesting that acetamiprid and its metabolites tended to persist in the honeybee. Acetamiprid was rapidly distributed in all compartments and metabolized. Just after administration, radioactivity was mainly localized in the abdomen and subsequently in the rectum. After 72 h, the maximum amount of radioactivity (about 20% of the ingested dose) was detected again in the abdomen, whereas the lowest level of total radioactivity was detected in the haemolymph. Radioactivity in the head did not exceed 7.6% of total ingested radioactivity. More than 50% of acetamiprid was metabolised in less than 30 min, indicating a very short half‐life for the compound. During the first hours, acetamiprid was mainly detected in nicotinic acetylcholine receptor‐rich tissues: abdomen, thorax and head. Of the seven metabolites detected, the major ones were 6‐choronicotinic acid and an unknown metabolite called U1, which was present mainly in the rectum, the thorax and the head. Our results indicate that the low toxicity of acetamiprid may reflect its rapid metabolism. Copyright © 2005 Society of Chemical Industry
Influence of source/drain contacts on sub‐micrometer organic field‐effect transistors
Authors: Scheinert S. , Paasch G. , Hörselmann I. , Herasimovich A. 
Published: May 2005

AbstractMeasured output characteristics of our prepared short‐channel organic transistor show the well known effect of a nonlinear increase of the drain current with positive curvature at low drain voltages. We investigated this peculiarity by means of 2D simulations considering the bilayer contact for source or drain, respectively. The simulations show that the low work function of the chromium adhesion layer causes the nonlinearity. Another important aspect demonstrated by the simulations is the estimation of the mobility applying the simple Shockley equation. The influence of the contact properties on the rise of the drain current results in erroneous values for the mobility as estimated directly from the current–voltage characteristics.
Output characteristics of a 1 µm channel length transistor.magnified imageOutput characteristics of a 1 µm channel length transistor.(© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Consistent QED approach to calculation of electron‐collision excitation cross sections and strengths: Ne‐like ions
Authors: Glushkov Alexander V. , Ambrosov Sergey V. , Loboda Andrey V. , Gurnitskaya Elena P. , Prepelitsa Georgy P. 
Published: May 2005

AbstractWe present the uniform energy approach, formally based on the quantum electrodynamics, using the gauge invariant scheme of generation of the optimal one‐electron representation, for the calculation of electron‐collision strengths and cross sections. The aim is to study, in a uniform manner, elementary processes responsible for emission‐line formation in plasmas. The electron‐collision excitation cross sections and strengths for some Ne‐like ions (Fe, Ba) are calculated. To test the results of calculations, we compare them with the calculations of other investigators and with the available experimental data. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Water‐Soluble Sacrificial Layers for Surface Micromachining
Authors: Linder Vincent , Gates Byron D. , Ryan Declan , Parviz Babak A. , Whitesides George M. 
Published: May 2005

AbstractThis manuscript describes the use of water‐soluble polymers for use as sacrificial layers in surface micromachining. Water‐soluble polymers have two attractive characteristics for this application: 1) They can be deposited conveniently by spin‐coating, and the solvent removed at a low temperature (95–150 °C), and 2) the resulting layer can be dissolved in water; no corrosive reagents or organic solvents are required. This technique is therefore compatible with a number of fragile materials, such as organic polymers, metal oxides and metals—materials that might be damaged during typical surface micromachining processes. The carboxylic acid groups of one polymer—poly(acrylic acid) (PAA)—can be transformed by reversible ion‐exchange from water‐soluble (Na+counterion) to water‐insoluble (Ca2+counterion) forms. The use of PAA and dextran polymers as sacrificial materials is a useful technique for the fabrication of microstructures: Examples include metallic structures formed by the electrodeposition of nickel, and freestanding, polymeric structures formed by photolithography.