bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poisson's ratio of simple planar ‘isotropic’ solids in two dimensions
Authors: Tretiakov Konstantin V. , Wojciechowski Krzysztof W. 
Published: January 2007

AbstractThe influence of molecular geometry on the Poisson's ratio has been investigated for a few two‐dimensional (2D) hard body systems (hard discs, hard dimers, hard cyclic trimers, and hard cyclic hexamers) forming elastically isotropic solid phases. The Poisson's ratio of the studied periodic and aperiodic solids was determined by Monte Carlo simulations using the analysis of the box fluctuations in the constant pressure ensemble (NpT) with variable box shape. The results obtained for all the studied systems showed that the Poisson's ratio grows when the density is decreased. It has been also found that the Poisson's ratio decreases with increasing number of discs in the molecule and its value for hard trimers is negative near close packing. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Is there a ‘matrix suppression effect’ under fast‐atom bombardment liquid secondary ion mass spectrometry of ionic surfactants in glycerol?
Authors: Kosevich Marina V. , Chagovets Vitalij V. , Shelkovsky Vadim S. , Boryak Oleg A. , Orlov Vadim V. , Gomory Agnes , Vegh Peter 
Published: January 2007

AbstractSome features of a ‘matrix suppression effect’ caused by ionic surface‐active compounds under fast‐atom bombardment (FAB) liquid secondary ion mass spectrometry (LSIMS) are being revised. It is shown that abundant transfer of the glycerol matrix molecules to the gas phase does occur under FAB‐LSIMS of ionic surfactants, contrary to popular belief. This process can be obscure because of the dependence of the charge state of the glycerol‐containing cluster ions on the type of ionic surfactant. It is revealed that, while glycerol matrix signals are really completely suppressed in the positive ion mass spectra of cationic surfactants (decamethoxinum, aethonium), abundant deprotonated glycerol and glycerol‐anion clusters are recorded in the negative ion mode. In the case of an anionic surfactant (sodium dodecyl sulfate), on the contrary, glycerol is completely suppressed in the negative ion mode, but is present in the protonated and cationized forms in the positive ion mass spectra. It is suggested that such patterns of positive and negative ion FAB‐LSIMS spectra of ionic surfactants solutions reflect the structure and composition of the electric double layer formed at the vacuum‐liquid interface by organic cations or anions and their counterions. Processes leading to the formation of the glycerol‐containing ions preferentially of positive or negative charge are discussed. The most obvious of them is efficient binding of glycerol to inorganic counterions of the salts Cl− or Na+, which is confirmed by data from quantum chemical calculations. The high content of the counterions and relatively small content of glycerol in the sputtered zone may be responsible for the charge‐selective suppression of neat glycerol clusters of opposite charge to the counterions. In the case of a mixture of cationic and anionic surfactants the substitution of inorganic counterions by organic ones was observed. The dependence of the exchange rate in the surface layer is not a linear function of the bulk solution concentration, and an effect of abrupt recharging of the surface can be registered. No both positively or negatively charged pure glycerol and glycerol‐inorganic counterion clusters are recorded for the mixture. Correlations between the mass spectrometric observations and some phenomena of surface and colloid chemistry and physics are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Oxygen‐18 measurement of Andalusian olive oils by continuous flow pyrolysis/isotope ratio mass spectrometry
Authors: Aramendía María A. , Marinas Alberto , Marinas José M. , Moreno José M. , Moalem Mustafa , Rallo Luis , Urbano Francisco J. 
Published: January 2007

AbstractWe report a method for the determination of δ18O isotopic abundance in olive oils. The results obtained by applying the method to various Andalusian oil samples obtained in the 2004/05 and 2005/06 seasons are discussed in relation to olive variety, geographical origin, climate and ripeness index. Application of the method to samples of assured varietal purity exposed the influence of olive variety and origin but not of the ripeness index. The δ18O values for the 2005/06 season are higher on average than those obtained in the colder 2004/05 season. Results obtained for samples of the Picual and Hojiblanca varieties in Córdoba and Málaga in the 2005/06 season suggest a correlation between enrichment in heavy isotopes and latitude whereas no clear‐cut effect of altitude was observed. Copyright © 2007 John Wiley & Sons, Ltd.
Making patient‐level estimates from medical encounter records using a multiplicity estimator
Authors: Burt Catharine W. , Hing Esther 
Published: January 2007

AbstractThe National Ambulatory Medical Care Survey (NAMCS) is a nationally representative survey of medical encounters in physician offices in the United States. Data from this survey and its counterpart in hospitals, the National Hospital Ambulatory Medical Care Survey (NHAMCS), have been used to investigate physician treatment and prescribing patterns. A limitation of these data, however, is that they represent visits rather than patients. Starting in 2001, the survey questionnaires began collecting information on the number of past visits the patient had to the sample provider during the one‐year period prior to the sampled visit. This information was used to estimate number of patients from the NAMCS and NHAMCS visit data using a multiplicity estimator. The resulting distribution of patients by the number of annual visits is similar to the distribution of persons in the U.S. making ambulatory care visits from a population‐based survey. This estimation technique may be useful in estimating patients with clinical characteristics that are difficult to collect from a population‐based survey. Published in 2007 by John Wiley & Sons, Ltd.
Screening for pre‐eclampsia and fetal growth restriction by uterine artery Doppler and PAPP‐A at 11–14 weeks' gestation
Authors: Pilalis A. , Souka A. P. , Antsaklis P. , Daskalakis G. , Papantoniou N. , Mesogitis S. , Antsaklis A. 
Published: January 2007

AbstractObjectiveTo assess the role of maternal demographic characteristics, uterine artery Doppler velocimetry, maternal serum pregnancy‐associated plasma protein‐A (PAPP‐A) and their combination in screening for pre‐eclampsia and small‐for‐gestational age (SGA) fetuses at 11–14 weeks.MethodsThis was a prospective study of 878 consecutive women presenting for a routine prenatal ultrasound examination at 11–14 weeks. Pulsed wave Doppler was then used to obtain uterine artery flow velocity waveforms and the mean pulsatility index (PI) of the uterine arteries was calculated. Maternal serum samples for PAPP‐A were assayed. Along with maternal history, these measurements were compared in their ability to predict adverse outcome, defined as pre‐eclampsia and/or SGA and/or placental abruption.ResultsMean uterine artery PI ≥ 95th centile and PAPP‐A ≤ 10th centile each predicted 23% of the women that developed pre‐eclampsia and 43% of cases of placental abruption. For SGA ≤ 5th centile, mean uterine artery PI ≥ 95th centile predicted 23% of cases and PAPP‐A ≤ 10th centile predicted 34%. Independent predictors for subsequent development of pre‐eclampsia were increased mean uterine artery PI ≥ 95th centile (OR, 2.76; 95% CI, 1.11–6.81) and maternal history of pre‐eclampsia/hypertension (OR, 50.54; 95% CI, 10.52–242.73). The predicting factors for SGA ≤ 5th centile were increased mean uterine artery PI ≥ 95th centile (OR, 2.0; 95% CI, 1.07–3.74) and low PAPP‐A (OR, 0.43; 95% CI, 0.20–0.93). Increased uterine artery PI was the only independent factor in the prediction of placental abruption (OR, 8.49; 95% CI, 2.78–25.94). The combination of uterine artery PI and maternal history of pre‐eclampsia/hypertension was better than was using uterine artery Doppler alone in predicting pre‐eclampsia. Similarly, for the prediction of SGA ≤ 5th centile, combining uterine artery Doppler and maternal serum PAPP‐A was better than was uterine artery Doppler alone. In both cases, the difference approached statistical significance.ConclusionsThe combination of maternal history with abnormal uterine artery Doppler and low PAPP‐A level at 11–14 weeks achieves better results than does either test alone in the prediction of pre‐eclampsia and SGA. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Barley Protein Isolate: Thermal, Functional, Rheological, and Surface Properties
Authors: Mohamed Abdellatif , Hojilla‐Evangelista Mila P. , Peterson Steve C. , Biresaw Girma 
Published: January 2007

AbstractBarley protein isolate (BPI) was extracted in 0.015 N NaOH in a 10:1 ratio solvent:flour and was precipitated by adjusting the pH to 4.5 and freeze‐dried. The thermal properties of BPI were determined using modulated differential scanning calorimetry (MDSC). BPI with 4% moisture content exhibited a glass transition (Tg) with 140 °C onset, 153 °C middle, and 165 °C end temperatures and a ΔCp of 0.454 J/g per °C. The high moisture content sample (50%) showed a Tg at 89, 91, or 94 °C and 0.067 ΔCp. Acetylation had no apparent effect on the foaming and emulsifying properties of protein from barley flour but exhibited the least‐stable foam among BPI samples. Foaming capacities of both barley protein isolates were ∼12% less than that of acid‐precipitated soy protein isolate reported in the literature. Acetylated BPI showed the highest surface hydrophobicity compared to the other samples. The surface‐tension test confirmed that unmodified and modified BPI possessed surface activity. BPI phosphorous oxycloride‐crosslinked was the most effective in lowering the surface tension of aqueous NaCl, while the crosslinked BPI was the least effective. The G′ value of BPI suspension was greater than G″ at all frequencies from 0.1 to 100 rad/s. The strain value at which linear behavior ceased and nonlinear behavior began ranged from 3 to 10%.
Thiazolidinediones exhibit different effects on preadipocytes isolated from rat mesenteric fat tissue and cell line 3T3‐L1 cells derived from mice
Authors: Mineo Hitoshi , Oda Chikako , Chiji Hideyuki , Kawada Teruo , Shimizu Kyoko , Taira Toshio 
Published: January 2007

AbstractThe effects of PPAR‐γ agonists, thiazolidinediones (TZDs), on preadipocytes isolated from rat mesenteric adipose tissue and murine cell line 3T3‐L1 were compared using an in vitro cell culture system. After each cell formed a confluent monolayer under appropriate medial conditions, pioglitazone or troglitazone was applied at 10 μM to each medium for cell maturation. We observed morphological changes in each cell, especially the accumulation of lipid droplets in the cytoplasm, during the culture periods. At the end of culture, DNA content, triglyceride (TG) content and glycerol‐3‐phosphate dehydrogenase (GPDH) activity were determined. Adiponectin concentrations in each culture medium were also measured during appropriate experimental periods. Application of TZDs increased the DNA content, TG accumulation and GPDH activity in the 3T3‐L1 cells but not in the mesenteric adipocytes. Although TG accumulation was unchanged, the number of lipid particles was decreased and the size of lipid particles in the mesenteric adipocytes was increased by TZD application. Although the TZDs increased adiponectin release from the 3T3‐L1 cells, adiponectin release from mesenteric adipocytes was suppressed (P < 0.05). Thus, the effects of TZDs differed between the primary culture of mesenteric adipose cells and the line cell culture of 3T3‐L1 cells. The source of adipocytes is an important factor in determining the action of TZDs in vitro, and particular attention should be paid when evaluating the effect of PPAR‐γ agonists on adipose tissues.
Induction of apoptosis in rat C6 glioma cells by panaxydol
Authors: Hai Jian , Lin Qi , Lu Yang , Zhang Hao , Yi Jing 
Published: January 2007

AbstractPanaxydol is a naturally occurring non‐peptidyl small molecule isolated from the lipophilic fractions of Panax notoginseng, a well‐known Chinese traditional medicine. Previous studies have shown that panaxydol inhibited the growth of various kinds of malignant cell lines. To date, there has been no report concerning the effect of panaxydol on cell growth inhibition in glioma cells. In this paper, we examined panaxydol's antiproliferation and proapoptotic effects on rat C6 glioma cells and investigated its mechanism. Cell growth inhibition of panaxydol was determined by MTT reduction assay. Apoptosis of cells was measured by both Hoechst 33258 staining and Annexin V analysis. It was found that panaxydol markedly inhibited proliferation of C6 cells in a dose‐dependent manner with ID50 of 40 μM. The cell apoptosis was observed at 48 h in the presence of panaxydol. In concert with these findings, Western blot analysis showed a decreased expression of bcl‐2 and increased levels of Bax and caspase‐3 in C6 cells treated by panaxydol. In conclusion, panaxydol has profound effects on growth and apoptosis of C6 cells, suggesting that panaxydol may be a potential candidate for the treatment of malignant gliomas.
Antioxidant metabolism in Xenopus laevis embryos is affected by stratospheric balloon flight
Authors: Rizzo Angela M. , Rossi Federica , Zava Stefania , Montorfano Gigliola , Adorni Laura , Cotronei Vittorio , Zanini Alba , Berra Bruno 
Published: January 2007

AbstractTo test the effects of low levels of radiation from space on living organisms, we flew Xenopus laevis embryos at different stages of development on a stratospheric balloon (BI.R.BA mission). After recovery, different parameters were analyzed to assess the effects of flight, with particular regard to oxidative stress damage. Because of failed temperature control during flight, the flight shielded embryos (FC) could not be used for biochemical or morphological comparisons. In contrast, the incubation conditions (i.e. temperature, containers, volumes) for the flight embryos (F) were parallel to those for the ground controls. Mortality data show that younger embryos (16 h) flown on the balloon (F) are more sensitive to radiation exposure than older ones (40 h and 6 days). Exposure during flight lowered the antioxidant potential in all embryos, particularly older ones. These preliminary data demonstrate that flight on a stratospheric balloon might affect antioxidant metabolism, though it is not yet possible to correlate these results with low radiation exposure during flight.
Perception for ischemic pain shows similarities in adjustment disorder and major depression
Authors: Boettger M.K. , Bär K.J. 
Published: January 2007

AbstractWe recently described an increase of pain thresholds and tolerances for thermal and electrical pain in patients suffering from adjustment disorder (AD). Furthermore, we presented evidence that pain perception in major depressive disorder (MDD) depends on pain modality, with thresholds for ischemic pain being decreased compared to increased thermal and electrical pain thresholds.Here, we investigated perception of experimentally induced ischemic pain in 15 patients suffering from AD (subtype with depressive symptoms) and controls matched for age and sex in order to examine whether a similar pattern of modality dependent pain perception can be established. Thresholds and tolerances were assessed on both sides of the body.We found a significant decrease of ischemic pain thresholds in AD patients as compared to controls. Analogue findings have been reported for pain perception in MDD, therefore suggesting similarities with regards to pain perception in both disorders.This adds weight to the assumption that depressive symptomatology might alter pain sensitivity in this subtype of AD since symptoms are milder, yet comparable to MDD.
Psychiatric problems and first year examinations in overseas students at Edinburgh University
Authors: Cox J.L. , Babiker I.E. , Miller P.McC. 
Published: January 2007

The relationships between psychiatric illness, lesser degrees of psychiatric symptoms and first year examination results in 121 students of foreign nationality or domiciled overseas are described.Overseas students were reasonably happy at the start of the year. This happiness declined as the winter progressed and then picked up again in the Easter term. It was, however, only the happiness level in the month of February that predicted academic failure.Symptoms of anxiety, depression and headache during the Easter term were also found to correlate significantly with first year examination failure. However, only eight students had a definite psychiatric disorder and only one student was referred to the psychiatrist. The practical implications of these findings for the organization of Student Health Services, with particular reference to the needs of overseas students, are discussed.
A survey of zoonotic pathogens carried by Norway rats in Baltimore, Maryland, USA
Authors: EASTERBROOK J. D. , KAPLAN J. B. , VANASCO N. B. , REEVES W. K. , PURCELL R. H. , KOSOY M. Y. , GLASS G. E. , WATSON J. , KLEIN S. L. 
Published: January 2007

SUMMARYNorway rats (Rattus norvegicus) carry several zoonotic pathogens and because rats and humans live in close proximity in urban environments, there exists potential for transmission. To identify zoonotic agents carried by rats in Baltimore, Maryland, USA, we live-trapped 201 rats during 2005–2006 and screened them for a panel of viruses, bacteria, and parasites. Antibodies against Seoul virus (57·7%), hepatitis E virus (HEV, 73·5%),Leptospira interrogans(65·3%),Bartonella elizabethae(34·1%), andRickettsia typhi(7·0%) were detected in Norway rats. Endoparasites, includingCalodium hepatica(87·9%) andHymenolepissp. (34·4%), and ectoparasites (13·9%, primarilyLaelaps echidninus) also were present. The risk of human exposure to these pathogens is a significant public health concern. Because these pathogens cause non-specific and often self-limiting symptoms in humans, infection in human populations is probably underdiagnosed.
Incidence of cryptosporidiosis species in paediatric patients in Malawi
Authors: MORSE T. D. , NICHOLS R. A. B. , GRIMASON A. M. , CAMPBELL B. M. , TEMBO K. C. , SMITH H. V. 
Published: January 2007

SUMMARYWe determined the incidence of cryptosporidiosis in children aged <5 years presenting with diarrhoea in an urban and rural hospital-based setting in Malawi. Stools were collected over a 22-month period during both rainy and dry seasons. A range of microscopic methods were used to determine the presence ofCryptosporidiumspp. oocysts. Species determination was by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) of oocyst-extracted DNA using 18S rRNA and COWP gene loci.Cryptosporidiumspp. oocysts were seen in 5·9% (50/848) of samples, of which 43 amplified by PCR–RFLP indicated the following species:C. hominis,C. parvum,C. hominis/C. parvum,C. meleagridisandC. andersoni. Seven samples could not be amplified by PCR. Wider species diversity was found in the rural setting, and may be a result of increased malnutrition and zoonotic exposure in this area. Improvements in water, sanitation, household hygiene and animal control are required to reduce the incidence of infection in this population.
Perfusion Culture of Hybridoma Cells for Hyperproduction of IgG2a Monoclonal Antibody in a Wave Bioreactor‐Perfusion Culture System
Authors: Tang Ya‐Jie , Ohashi Ryo , Hamel Jean‐François P. 
Published: January 2007

AbstractA novel wave bioreactor‐perfusion culture system was developed for highly efficient production of monoclonal antibody IgG2a (mAb) by hybridoma cells. The system consists of a wave bioreactor, a floating membrane cell‐retention filter, and a weight‐based perfusion controller. A polyethylene membrane filter with a pore size of 7 μm was floating on the surface of the culture broth for cell retention, eliminating the need for traditional pump around flow loops and external cell separators. A weight‐based perfusion controller was designed to balance the medium renewal rate and the harvest rate during perfusion culture. BD Cell mAb Medium (BD Biosciences, CA) was identified to be the optimal basal medium for mAb production during batch culture. A control strategy for perfusion rate (volume of fresh medium/working volume of reactor/day, vvd) was identified as a key factor affecting cell growth and mAb accumulation during perfusion culture, and the optimal control strategy was increasing perfusion rate by 0.15 vvd per day. Average specific mAb production rate was linearly corrected with increasing perfusion rate within the range of investigation. The maximum viable cell density reached 22.3 × 105 and 200.5 × 105 cells/mL in the batch and perfusion culture, respectively, while the corresponding maximum mAb concentration reached 182.4 and 463.6 mg/L and the corresponding maximum total mAb amount was 182.4 and 1406.5 mg, respectively. Not only the yield of viable cell per liter of medium (32.9 × 105 cells/mL per liter medium) and the mAb yield per liter of medium (230.6 mg/L medium) but also the mAb volumetric productivity (33.1 mg/L·day) in perfusion culture were much higher than those (i.e., 22.3 × 105 cells/mL per liter medium, 182.4 mg/L medium, and 20.3 mg/L·day) in batch culture. Relatively fast cell growth and the perfusion culture approach warrant that high biomass and mAb productivity may be obtained in such a novel perfusion culture system (1 L working volume), which offers an alternative approach for producing gram quantity of proteins from industrial cell lines in a liter‐size cell culture. The fundamental information obtained in this study may be useful for perfusion culture of hybridoma cells on a large scale.
Number of nitrate groups determines reactivity and potency of organic nitrates: a proof of concept study in ALDH‐2−/− mice
Authors: Wenzel P , Hink U , Oelze M , Seeling A , Isse T , Bruns K , Steinhoff L , Brandt M , Kleschyov A L , Schulz E , Lange K , Weiner H , Lehmann J , Lackner K J , Kawamoto T , Münzel T , Daiber A 
Published: January 2007

Background and purpose:Mitochondrial aldehyde dehydrogenase (ALDH‐2) has been shown to provide a pathway for bioactivation of organic nitrates and to be prone to desensitization in response to highly potent, but not to less potent, nitrates. We therefore sought to support the hypothesis that bioactivation by ALDH‐2 critically depends on the number of nitrate groups within the nitrovasodilator.Experimental approach:Nitrates with one (PEMN), two (PEDN; GDN), three (PETriN; glyceryl trinitrate, GTN) and four (pentaerithrityl tetranitrate, PETN) nitrate groups were investigated. Vasodilatory potency was measured in isometric tension studies using isolated aortic segments of wild type (WT) and ALDH‐2−/− mice. Activity of the cGMP‐dependent kinase‐I (reflected by levels of phosphorylated VAsodilator Stimulated Phosphoprotein, P‐VASP) was quantified by Western blot analysis, mitochondrial dehydrogenase activity by HPLC. Following incubation of isolated mitochondria with PETN, PETriN‐chromophore and PEDN, metabolites were quantified using chemiluminescence nitrogen detection and mass spectrometry.Key results:Compared to WT, vasorelaxation in response to PETN, PETriN and GTN was attenuated about 10fold in ALDH‐2−/− mice, identical to WT vessels preincubated with inhibitors of ALDH‐2. Reduced vasodilator potency correlated with reduced P‐VASP formation and diminished biotransformation of the tetranitrate‐ and trinitrate‐compounds. None of these findings were observed for PEDN, GDN and PEMN.Conclusions and implications:Our results support the crucial role of ALDH‐2 in bioactivating highly reactive nitrates like GTN, PETN and PETriN. ALDH‐2‐mediated relaxation by organic nitrates therefore depends mainly on the number of nitrate groups. Less potent nitrates like PEDN, GDN and PEMN are apparently biotransformed by other pathways.British Journal of Pharmacology (2007) 150, 526–533. doi:10.1038/sj.bjp.0707116