bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fitting models for the joint action of two drugs using SAS(R)
Authors: Whitehead Anne , Whitehead John , Todd Susan , Zhou Yinghui , Smith Michael K 
Published: November 2007

AbstractCombinations of drugs are increasingly being used for a wide variety of diseases and conditions. A pre‐clinical study may allow the investigation of the response at a large number of dose combinations. In determining the response to a drug combination, interest may lie in seeking evidence of ‘synergism’, in which the joint action is greater than the actions of the individual drugs, or of ‘antagonism’, in which it is less. Two well‐known response surface models representing no interaction are Loewe additivity and Bliss independence, and Loewe or Bliss synergism or antagonism is defined relative to these. We illustrate an approach to fitting these models for the case in which the marginal single drug dose–response relationships are represented by four‐parameter logistic curves with common upper and lower limits, and where the response variable is normally distributed with a common variance about the dose–response curve. When the dose–response curves are not parallel, the relative potency of the two drugs varies according to the magnitude of the desired effect and the models for Loewe additivity and synergism/antagonism cannot be explicitly expressed. We present an iterative approach to fitting these models without the assumption of parallel dose–response curves. A goodness‐of‐fit test based on residuals is also described. Implementation using the SAS NLIN procedure is illustrated using data from a pre‐clinical study. Copyright © 2007 John Wiley & Sons, Ltd.
The even‐electron rule in electrospray mass spectra of pesticides
Authors: Thurman E. Michael , Ferrer Imma , Pozo Oscar J. , Sancho Juan V. , Hernandez Felix 
Published: November 2007

AbstractA study of the fragmentation and ion formation of three major families of pesticides (including herbicides, insecticides, and fungicides) by liquid chromatography/time‐of‐flight mass spectrometry (LC/TOF‐MS) and liquid chromatography/quadrupole time‐of‐flight mass spectrometry (LC/Q‐TOF‐MS) was carried out using positive electrospray ionization (ESI) and the results compared with those by gas chromatography (GC)/TOF‐MS with electron ionization (EI) in order to test the validity of the even‐electron rule in electrospray ionization. First, the majority of the fragmenta ions by positive ion ESI were even electron (EE) ions (93% of the fragment ions). Secondly, the formation of odd‐electron (OE) fragment ions was greater with EI, where the fragment ions were present in a ratio of approximately 1:2 (35% OE ions and 65% EE ions). Thirdly, in‐source collision‐induced dissociation (CID) fragmentation by LC/TOF‐MS and CID fragmentation in the collision cell by LC/Q‐TOF‐MS/MS resulted in 95% of the fragment ions being identical between the two types of fragmentation. As ESI in the positive ion mode yields an EE precursor ion (normally a protonated molecule), this commonly leads to EE fragment ions by elimination of molecules – a process called the even‐electron rule. Neutral radical losses were less common in ESI but were common in the EI spectra of the same compounds. The structures that did lead to OE ions in ESI (exceptions to the even‐electron rule ∼7% of all ESI ions) favored electronegative radical losses in approximately the following order: ·SO2CH3, ·NO2, ·CH3, ·Cl, ·SCH3, ·CH2CH, and ·OH. Copyright © 2007 John Wiley & Sons, Ltd.
How many dimensions does sustainable development have?
Authors: Pawłowski Artur 
Published: November 2007

AbstractThere is only a scant possibility of today's environmental problems being solved solely by technical means, with no account being taken of the social or economic aspects. Thus, three generally recognized dimensions of sustainable development have been devised: ecological, social and economic. However, the basis for them is moral reflection regarding humankind's responsibility for nature. Is this all? Perhaps we should also include technical, legal and political dimensions. All of them are important and all of them are characterized in this paper. Since they are connected with one another, examples of the degree to which they can overlap are also discussed. Copyright © 2007 John Wiley & Sons, Ltd and ERP Environment.
Evaluating a surrogate endpoint at three levels, with application to vaccine development
Authors: Gilbert Peter B. , Qin Li , Self Steven G. 
Published: November 2007

AbstractIdentification of an immune response to vaccination that reliably predicts protection from clinically significant infection, i.e. an immunological surrogate endpoint, is a primary goal of vaccine research. Using this problem of evaluating an immunological surrogate as an illustration, we describe a hierarchy of three criteria for a valid surrogate endpoint and statistical analysis frameworks for evaluating them. Based on a placebo‐controlled vaccine efficacy trial, the first level entails assessing the correlation of an immune response with a study endpoint in the study groups, and the second level entails evaluating an immune response as a surrogate for the study endpoint that can be used for predicting vaccine efficacy for a setting similar to that of the vaccine trial. We show that baseline covariates, innovative study design, and a potential outcomes formulation can be helpful for this assessment. The third level entails validation of a surrogate endpoint via meta‐analysis, where the goal is to evaluate how well the immune response can be used to predict vaccine efficacy for new settings (building bridges). A simulated vaccine trial and two example vaccine trials are presented, one supporting that certain anti‐influenza antibody levels are an excellent surrogate for influenza illness and another supporting that certain anti‐HIV antibody levels are not useful as a surrogate for HIV infection. Copyright © 2007 John Wiley & Sons, Ltd.
Predicting and measuring alliance performance: a multidimensional analysis
Authors: Lunnan Randi , Haugland Sven A. 
Published: November 2007

AbstractThe strategic alliance literature demonstrates that alliances create value for the partners, but also that many alliances fall short of expectations. This study addresses the complex issue of alliance performance. We follow 100 contractual alliances over a 5‐year period, and study their performance in terms of abrupt termination, short‐term performance, and long‐term performance. The results indicate that alliances that are considered strategically important are less likely to be abruptly terminated. We also find that newly established alliances have a higher termination rate than older alliances. Short‐term performance is primarily affected by access to complementary and strategically important resources, whereas long‐term performance is related to specific investments in human capital combined with the partners' ability to develop and expand alliance activities over time. Copyright © 2007 John Wiley & Sons, Ltd.
Impacts of Organizational Culture and Personality Traits on Decision‐making in Technical Organizations
Authors: Briggs Clark , Little Patrick 
Published: November 2007

AbstractTechnical organizations in industries such as aerospace or automotive regularly make major decisions regarding software and other tools to support mission‐critical activities. These decisions take place at the enterprise level where functional departments must work together in ways not common before. Usually, these are high‐impact, tension‐filled decision activities that have long term effects. The organization needs a successful decision that stands the test of implementation and a sustained period of effective operation. The processes used in such cases generally follow analytical decision methods aimed at maximizing objectives. Understanding the characteristics of the organization, including the culture and the affected parties, in addition to the technical aspects of the decision may significantly increase the likelihood of success. © 2007 Wiley Periodicals, Inc. Syst Eng
Profiles of freshman physics students' views on the nature of science
Authors: Ibrahim Bashirah , Buffler Andy , Lubben Fred 
Published: November 2007

AbstractThe views on various aspects of the nature of science (NOS) of 179 novice undergraduate physics students were investigated using six open‐ended, written probes. These views were consolidated within compact NOS “profiles,” which were designed based on the students' responses to the probes. These profiles may be understood as sets of key descriptors, which represented the variation in the views of individual students in a succinct way. The views of 86% of the sample were found to be represented by four profiles, each containing five descriptors. The consequences for the teaching and learning of tertiary science, and advantages for linking NOS views to other research observables were explored. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 46: 248–264, 2009
Umbilical artery half peak systolic velocity deceleration time throughout pregnancy and its role in fetuses with bradycardia
Authors: Bustos J. C. , Paublo M. , Ramirez P. , Sepulveda W. 
Published: November 2007

AbstractObjectivesTo describe a new technique for Doppler waveform quantification of the fetal umbilical artery, the half peak systolic velocity (h‐PSV) deceleration time, which measures the time that it takes a single flow velocity waveform to halve its maximum systolic velocity. As this measurement is independent of fetal heart rate, its role in the evaluation of placental vascular resistance in fetuses with bradycardia was also explored.MethodsThe umbilical artery impedance indices and the h‐PSV deceleration time were measured in 532 normal singleton fetuses from 17 to 41 weeks of gestation. A nomogram was established and its usefulness in assessing fetuses with bradycardia was evaluated.ResultsThe relationship between umbilical artery h‐PSV deceleration time and gestational age was best described by a linear formula (y = 6.5523x + 12.41; R2 = 0.6346), h‐PSV deceleration time increasing by 6.6 ms per week. The correlation coefficients for the 95th, 50th and 5th centiles were 0.97, 0.98 and 0.98, respectively. Measurement of h‐PSV deceleration time was reproducible, with interobserver and intraobserver variabilities of 10.7% and 7.4%, respectively. Among fetuses with bradycardia (n = 7), the h‐PSV deceleration time was above the 5th centile in all cases, suggesting normal placental function in spite of abnormally increased impedance indices obtained with traditional Doppler indices in six.ConclusionsThe h‐PSV deceleration time increases linearly during the second and third trimesters of pregnancy. As its measurement is reproducible and independent of heart rate, it may be useful in the assessment of well‐being in fetuses with bradycardia. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Influence of GaAs Substrate Orientation on InAs Quantum Dots: Surface Morphology, Critical Thickness, and Optical Properties
Authors: Liang BL , Wang Zh M , Sablon KA , Mazur Yu I , Salamo GJ 
Published: November 2007

Abstract
InAs/GaAs heterostructures have been simultaneously grown by molecular beam epitaxy on GaAs (100), GaAs (100) with a 2° misorientation angle towards [01−1], and GaAs (n 11)B (n = 9, 7, 5) substrates. While the substrate misorientation angle increased from 0° to 15.8°, a clear evolution from quantum dots to quantum well was evident by the surface morphology, the photoluminescence, and the time-resolved photoluminescence, respectively. This evolution revealed an increased critical thickness and a delayed formation of InAs quantum dots as the surface orientation departed from GaAs (100), which was explained by the thermal-equilibrium model due to the less efficient of strain relaxation on misoriented substrate surfaces.
Dietary Structured Lipids and Phytosteryl Esters: Blood Lipids and Cardiovascular Status in Spontaneously Hypertensive Rats
Authors: Kim Byung Hee , Sandock Kevin D. , Robertson Tom P. , Lewis Stephen J. , Akoh Casimir C. 
Published: November 2007

AbstractThis study examined the dietary effects of enzymatically modified sesame oil with caprylic acid (structured lipids, SL) and phytosteryl esters (PE) on blood lipid profiles and cardiovascular parameters of spontaneously hypertensive rats (SHR) fed high‐fat and high‐cholesterol (HFHC) diets. The dietary groups were: normal diet (control), sesame oil (SO), SL, SO fortified with PE (SOP), and SL fortified with PE (SLP). After 9 weeks of feeding, the body weights, liver weights, and liver weight/body weight ratios in all HFHC‐fed groups were higher than controls. Plasma total and LDL cholesterol levels in all HFHC‐fed groups were similar to one another but higher than those in controls. Plasma HDL cholesterol levels in rats fed SOP and SLP were higher than those in controls or rats fed SO and SL. Plasma HDL/total cholesterol ratios in rats fed SOP and SLP were similar to those in controls and were higher than those in rats fed SO and SL. There was no difference in plasma lipid profiles between rats fed SO and SL. Arterial blood pressures (BP) in conscious HFHC‐fed rats were similar to those in controls whereas heart rates (HR) in all HFHC‐fed groups were similar to one another but were higher than that in controls. These findings demonstrate that (1) the dietary effects of SL on plasma lipid profiles and resting BP and HR are similar to those of SO, (2) PE had positive effects on plasma lipid profiles, and (3) 9‐week intake of SL and PE did not have pronounced effects on resting BP but induced tachycardia in SHR.
Flaxseed Treatments to Reduce Biohydrogenation of α‐Linolenic Acid by Rumen Microbes in Cattle
Authors: Kronberg S. L. , Scholljegerdes E. J. , Barceló‐Coblijn G. , Murphy E. J. 
Published: November 2007

AbstractEnrichment of beef muscle with n‐3 fatty acids (FA) is one means to introduce these FA into the diet, but ruminal biohydrogenation limits their bioavailability. To address this problem, we evaluated the ability of condensed tannin (quebracho), in the presence or absence of casein, to protect 18:3n‐3 in flaxseed from hydrogenation by ruminal microbes in cattle using an in vitro fermentation approach coupled with evaluation in cattle in vivo. Treated and untreated flaxseed was incubated with bovine rumen fluid for 0 and 24 h. With tannin treated flaxseed, hydrogenation of 18:3n‐3 was limited to only 13% over 24 h compared to 43% for untreated flaxseed, while addition of casein to the tannin added no additional protection. To determine if a similar level of protection would occur in vivo, we used two groups of five steers fed either a grain‐based or forage‐based diet. Five steers were given a grain‐based diet during the trial and were fed either ground flaxseed or tannin treated flaxseed for 15 days prior to blood collection for plasma lipid fatty acid analysis. The forage fed steers followed the same regimen. Ingestion of tannin‐treated flaxseed did not increase 18:3n‐3 and 20:5n‐3 in plasma neutral lipids as compared to non‐treated flaxseed. Thus, we demonstrated that treating ground flaxseed with quebracho tannin is not useful for increasing 18:3n‐3 in the neutral lipid of bovine blood plasma, and suggest caution when interpreting results from in vitro trials that test potential treatments for protecting fatty acids from hydrogenation by ruminal microbes.
Effects of milk fermented byLactobacillusgasseriSBT2055 on adipocyte size in rats
Authors: Sato Masao , Uzu Kazunori , Yoshida Takeshi , Hamad Essam M. , Kawakami Hiroshi , Matsuyama Hiroaki , Abd El-Gawad Ibrahim A. , Imaizumi Katsumi 
Published: November 2007

Despite adequate scientific evidence of the potential benefits of probiotics to human health or disease prevention, their contribution to the growth of adipose tissue remains to be established. Four-week-old male Sprague-Dawley rats were fed a diet containing skim milk (control diet) or skim milk fermented byLactobacillus gasseriSBT2055 (LGSP diet) for 4 weeks. Their body weight gain, adipose tissue weight, adipocyte size distribution profile, blood and hepatic lipids, and serum leptin, glucose and adiponectin levels were determined. There was a significant reduction in average adipocyte size in mesenteric white adipose tissue (P = 0·004). Moreover, the rats fed the LGSP diet displayed greater numbers of small adipocytes from mesenteric and retroperitoneal adipose tissues than did those on the control diet. Whereas adiponectin concentrations did not differ between the groups, serum leptin concentrations were decreased to 32 % in the LGSP diet group compared with the control group. Concentrations of serum glucose and lipids, and liver lipids, except for the liver TAG level, were similar in the two groups. These results indicate a possible role for a fermented milk product in the regulation of adipose tissue growth.
Flavanol monomer-induced changes to the human faecal microflora
Authors: Tzounis Xenofon , Vulevic Jelena , Kuhnle Gunter G. C. , George Trevor , Leonczak Jadwiga , Gibson Glenn R. , Kwik-Uribe Catherine , Spencer Jeremy P. E. 
Published: November 2007

We have investigated the bacterial-dependent metabolism of ( − )-epicatechin and (+)-catechin using a pH-controlled, stirred, batch-culture fermentation system reflective of the distal region of the human large intestine. Incubation of ( − )-epicatechin or (+)-catechin (150 mg/l or 1000 mg/l) with faecal bacteria, led to the generation of 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone, 5-phenyl-γ-valerolactone and phenylpropionic acid. However, the formation of these metabolites from (+)-catechin required its initial conversion to (+)-epicatechin. The metabolism of both flavanols occurred in the presence of favourable carbon sources, notably sucrose and the prebiotic fructo-oligosaccharides, indicating that bacterial utilisation of flavanols also occurs when preferential energy sources are available. (+)-Catechin incubation affected the growth of select microflora, resulting in a statistically significant increase in the growth of theClostridium coccoides–Eubacterium rectalegroup,Bifidobacteriumspp. andEscherichia coli, as well as a significant inhibitory effect on the growth of theC. histolyticumgroup. In contrast, the effect of ( − )-epicatechin was less profound, only significantly increasing the growth of theC. coccoides–Eubacterium rectalegroup. These potential prebiotic effects for both (+)-catechin and ( − )-epicatechin were most notable at the lower concentration of 150 mg/l. As both ( − )-epicatechin and (+)-catechin were converted to the same metabolites, the more dramatic change in the growth of distinct microfloral populations produced by (+)-catechin incubation may be linked to the bacterial conversion of (+)-catechin to (+)-epicatechin. Together these data suggest that the consumption of flavanol-rich foods may support gut health through their ability to exert prebiotic actions.
The Sensitivity of the Dinoflagellate Crypthecodinium cohnii to Transient Hydrodynamic Forces and Cell‐Bubble Interactions
Authors: Hu Weiwei , Gladue Ray , Hansen Jon , Wojnar Crystal , Chalmers Jeffrey J. 
Published: November 2007

AbstractThe increased interest in the benefits of omega‐3 fatty acids for human health has resulted in the commercial development of the dinoflagellate Crypthecodinium cohnii for production of docosahexaenoic acid (DHA). The growing market demand for DHA requires highly efficient, very large scale cultures of DHA. While the effects of hydrodynamic forces on dinoflagellates have been investigated for several decades, the majority of the work focused on the negative effects of oceanic turbulence on the population growth of environmentally important dinoflagellates. In contrast, significantly less is known on the effect of hydrodynamic forces encountered by algae in bioprocesses. Unlike other studies conducted on algae, this study employed a microfluidic, flow contraction device to evaluate the effect of transient hydrodynamic forces on C. cohnii cells. It was found that C. cohnii cells can sustain the energy dissipation rate of 5.8 × 107 W/m3 without lysis. However, an obvious sublethal effect, the loss of flagella, was observed at a lower level of 1.6 × 107 W/m3. Finally the cell‐bubble interaction and the effect of bubble rupture were also explored to simulate the conditions of sparged bioreactors.
Internalization: what does it tell us about pharmacokinetic and pharmacodynamic properties of an antagonist?
Authors: Mueller A 
Published: November 2007

Chemokine receptors play an important role in trafficking leukocytes within the body, a process that depends on expression of the receptors on the cell surface. Expression levels are regulated by the rate of internalizing receptor compared to the rate of recycling/recovering receptor. Internalization is commonly induced by binding of agonists to their receptors that in turn use clathrin‐coated pits or caveolae to internalize. Joplin and colleagues describe a novel usage of internalization assays to determine pharmacokinetic/pharmacodynamic relationships of an antagonist on CXCR3 in a murine system. Intriguingly their results show that internalization assays give robust data about the pharmacokinetics/pharmacodynamics of different agonists and antagonists in an in vivo model. This kind of assay will allow investigations of the pharmacological properties of agonists and antagonists in a completely different setting and also give new insight into the regulation of cell surface expression of chemokine receptors and other G protein‐coupled receptors, which can lead to potential novel therapeutic targets.British Journal of Pharmacology (2007) 152, 1145–1146; doi:10.1038/sj.bjp.0707521; published online 5 November 2007
The role of abnormal trafficking of KCNE1 in long QT syndrome 5
Authors: Harmer S.C. , Tinker A. 
Published: November 2007

LQTS (long QT syndrome) is an important cause of cardiac sudden death. LQTS is characterized by a prolongation of the QT interval on an electrocardiogram. This prolongation predisposes the individual to torsade-de-pointes and subsequent sudden death by ventricular fibrillation. Mutations in a number of genes that encode ion channels have been implicated in LQTS. Hereditary mutations in the α- and β-subunits, KCNQ1 and KCNE1 respectively, of the K+ channel pore IKs are the commonest cause of LQTS and account for LQTS types 1 and 5 respectively (LQT1 and LQT5). Recently, it has been shown that disease pathogenesis in LQT1 can be influenced by the abnormal trafficking of KCNQ1. In comparison, whether defective trafficking of KCNE1 plays a role in LQT5 is less well established.
Homocysteine metabolism in diabetes
Authors: Wijekoon E.P. , Brosnan M.E. , Brosnan J.T. 
Published: November 2007

An increase in the plasma level of Hcy (homocysteine), an intermediate in the catabolism of methionine, has been identified as a risk factor for many diseases including CVD (cardiovascular disease). CVD is the major cause of death in patients with diabetes mellitus. Therefore the study of Hcy metabolism in diabetes mellitus has been a major focus of current research. Studies conducted in our laboratory were able to show that in both Type 1 and Type 2 diabetes with no renal complications, the plasma Hcy levels were lower than in controls. In Type 1 diabetes, increased activities of the trans-sulfuration enzymes were the major cause for the reduction in plasma Hcy. In Type 2 diabetes, BHMT (betaine:homocysteine methyltransferase) was also observed to play a major role in the increased catabolism of Hcy in addition to the trans-sulfuration enzymes. We were also able to demonstrate the direct effect of insulin and the counter-regulatory hormones on the regulation of cystathionine β-synthase and BHMT, which accounts for the changes in the activities of these two enzymes seen in diabetes mellitus.