bluuebunny/crossref_metadata_2025_split huggingface dataset:
On rotating rigid parallelograms and their potential for exhibiting auxetic behaviour
Authors: Attard Daphne , Manicaro Elaine , Grima Joseph N. 
Published: August 2009

AbstractAuxetic systems have the anomalous property of becoming wider when uniaxially stretched, i.e. exhibit a negative Poisson's ratio. One of the mechanisms which can give rise to this property is based on rotating rigid units, in particular 2D rigid polygons which are connected together at their corners through hinges and rotate relative to each other when uniaxially stretched. This work extends earlier preliminary work on connected rigid parallelograms and presents expressions for the mechanical properties for all the types of planar systems that can be constructed from rigid parallelograms of equal size connected at their vertices through flexible hinges. In particular, we derive and discuss the mechanical properties for the Type Iα, Iβ and IIβ rotating parallelograms which were not previously analysed and compare them with the properties of the Type IIα systems. We show that despite being rather similar to each other, the different types of ‘rotating parallelograms’ have very different mechanical properties and different abilities to exhibit auxetic behaviour.
A geometric confidence ellipse approach to the estimation of the ratio of two variables. Statistics in Medicine 2008; 27:5956–5974.
Authors: Walter S. D. , Gafni A. , Birch S. 
Published: August 2009

AbstractWe are grateful to Dr Etienne Kaelin for pointing out four typographic errors in the equations for this paper. These are as follows:

The term xy in equation (1) should be replaced by:

Equation (3) should be

The first term of the unnumbered equation after equation (3) should be µy rather than µx.
The correct version of equation (4) is

The numerical results of this paper as shown in the various tables are not affected by these errors because correct versions of the equations were used in their calculation.
Dr Kaelin has offered to make available an Excel spreadsheet that will carry out the calculations for the method described in this paper. It is available to interested readers by contacting him at Etienne.Kaelin@pmintl.com.
Performance of analytical methods for overdispersed counts in cluster randomized trials: Sample size, degree of clustering and imbalance
Authors: Durán Pacheco Gonzalo , Hattendorf Jan , Colford John M. , Mäusezahl Daniel , Smith Thomas 
Published: August 2009

AbstractMany different methods have been proposed for the analysis of cluster randomized trials (CRTs) over the last 30 years. However, the evaluation of methods on overdispersed count data has been based mostly on the comparison of results using empiric data; i.e. when the true model parameters are not known. In this study, we assess via simulation the performance of five methods for the analysis of counts in situations similar to real community‐intervention trials. We used the negative binomial distribution to simulate overdispersed counts of CRTs with two study arms, allowing the period of time under observation to vary among individuals. We assessed different sample sizes, degrees of clustering and degrees of cluster‐size imbalance. The compared methods are: (i) the two‐sample t‐test of cluster‐level rates, (ii) generalized estimating equations (GEE) with empirical covariance estimators, (iii) GEE with model‐based covariance estimators, (iv) generalized linear mixed models (GLMM) and (v) Bayesian hierarchical models (Bayes‐HM). Variation in sample size and clustering led to differences between the methods in terms of coverage, significance, power and random‐effects estimation. GLMM and Bayes‐HM performed better in general with Bayes‐HM producing less dispersed results for random‐effects estimates although upward biased when clustering was low. GEE showed higher power but anticonservative coverage and elevated type I error rates. Imbalance affected the overall performance of the cluster‐level t‐test and the GEE's coverage in small samples. Important effects arising from accounting for overdispersion are illustrated through the analysis of a community‐intervention trial on Solar Water Disinfection in rural Bolivia. Copyright © 2009 John Wiley & Sons, Ltd.
A comparison of model choices for the continual reassessment method in phase I cancer trials
Authors: Paoletti X. , Kramar A. 
Published: August 2009

AbstractDetermination of the maximum tolerated dose (MTD) is the main objective of phase I trials. Trials are typically carried out with restricted sample sizes. Model‐based approaches proposed to identify the MTD (including the Continual Reassessment Method or CRM) suppose a simple model for the dose‐toxicity relation. At this early stage of clinical development, the true family of models is not known and several proposals have been done. Asymptotic convergence of the recommendation to the true MTD can be obtained with a one‐parameter model even in case of model misspecification. Nevertheless, operating characteristics with finite sample sizes can be largely affected by the choice of the model.In this paper, we evaluate and compare several models in a simulation framework. This framework includes a large class of dose‐toxicity relations against which to test the competing models, an ‘optimal’ method that provides efficient non‐parametric estimates of the probability of dose limiting toxicity to serve as a benchmark and as a graphic representation. In particular we explore the use of a one‐parameter versus a two‐parameter model, we compare the power and the logistic models and finally we investigate the impact of dose recoding on the operating characteristics. Comparisons are carried out with both a likelihood approach and a Bayesian approach for model estimations. We show that average performances of a one‐parameter model are superior and that the power model has good operating characteristics. Some models can speed up dose escalation and lead to more aggressive designs.We derive some behavior related to the choice of model and insist on the use of simulations under several scenarios before the initiation of each new trial in order to determine the best model to be used. Copyright © 2009 John Wiley & Sons, Ltd.
A methodology for estimating and optimizing effectiveness of Non‐Independent Layered Defense
Authors: Kaminer Boaz I. , Ben‐Asher Joseph Z. 
Published: August 2009

AbstractFor many years, systems, developed to be integrated into a layered defense array, were planned through the “Stand Alone” paradigm, assuming that the layers of defense are independent. Almost all published literature dealing with Layered Defense automatically assumes that the layers of defense are independent of each other. The fact is they are not! Defense layers may influence one another in positive and/or negative ways. We attempt to initiate a new look at developing and deploying systems in an integrated array of defense systems, based on the understanding that influences between systems must be taken into account. A methodology for modeling the dependencies between defense systems engagements, of a single attacker, or of a salvo of attackers, is developed in this paper through an “Influence Decay Function” model. A tractable algorithm is developed to compute the complex effectiveness objective functions. The Non Independent Layered Defense Problem (NILDP) is formulated as a Mixed Integer Non Linear Programming problem. The optimization problem for maximum layered defense effectiveness is solved through powerful heuristic methods. The discussion deals with engineering defense systems to operate within complex environments which include not only threat from an opponent but also friendly systems to which integration is not at all trivial. © 2009 Wiley Periodicals, Inc. Syst Eng
Quantitative elemental analysis of individual particles with the use of micro‐beam X‐ray fluorescence method and Monte Carlo simulation
Authors: Czyzycki Mateusz , Bielewski Marek , Lankosz Marek 
Published: August 2009

AbstractThe aim of the work was to develop a Monte Carlo (MC) method and combine it with micro‐beam X‐ray fluorescence (XRF) technique for determination of chemical composition of individual particles. A collection of glass micro‐spheres, made of NIST (National Institute of Standards and Technoly) K3089 material of known chemical composition, with diameters in the range of 25–45 µm was investigated. The micro‐spheres were measured in a scanning micro‐beam XRF spectrometer utilising X‐ray tube as a source of primary radiation. Results obtained for low Z elements showed high dependence on particle size. It was found that the root mean square of concentration uncertainty, for the all elements present in the particle, increases with growing sample size. More accurate results were obtained for high Z elements such as Fe–Pb, as compared to others. The elemental percentage uncertainty did not exceed 14% for any particular sample and 6% for the whole group of the measured micro‐spheres as an average. Results obtained by the Monte Carlo method were compared with other analytical approaches. Copyright © 2009 John Wiley & Sons, Ltd.
Ein neuartiger Zugang zu reduzierten Polyoxomolybdaten mit komplexen Gegenionen – Synthese und Struktur von [Mn(CH3OH)6][Mo8O16(OCH3)8(C2O4)]
Authors: Sterzik Anke , Görls Helmar , Spielberg Eike T. , Plass Winfried , Imhof Wolfgang 
Published: August 2009

AbstractThe tetranuclear compound [Mo2(O2C‐tBu)3]2(μ‐C2O4) (1) that is prepared from [Mo2(O2C‐tBu)3]4 and oxalic acid, was reacted with MnI2·2THF to form the polyoxomolybdate compound [Mn(CH3OH)6] [Mo8O16(OCH3)8(C2O4)] (2) in a complex redox reaction. Crystals of 2 were analyzed by single‐crystal X‐ray diffraction showing a octanuclear polyoxomolybdate dianion in which the Mo=O moieties are alternately connected through μ‐oxo and μ‐methoxo units. Charge balance in 2 is realized by a manganese(II) cation that is octahedrally coordinated by methanol ligands. The crystal structure is dominated by strong hydrogen bond interactions of the O–H···O type of methanol molecules coordinated to manganese as well as additional methanol molecules in the crystal lattice.
Solvothermal Synthesis and Structural Characterization of an Organic‐Templated New Aluminogermanate with the GIS Topology
Authors: Sun Xiaochang , Liu Yanbo , Chen Qi , Liu Bing , Zhu Dunru , Xu Yan 
Published: August 2009

AbstractA new organic‐templated aluminogermanate [C4H12N][AlGe3O8] (1) has been prepared under solvothermal conditions by using 2‐propanol as solvent. The structure of the title compound was characterized by IR spectroscopic, elemental analysis, TG, single‐crystal X‐ray diffraction and powder X‐ray diffraction. Compound 1 crystallizes in the tetragonal space group I41/a, a = b = 10.7754(8) Å, c = 9.9116(14) Å, V = 1150.8(2) Å3, Z = 4. The structure of the title compound shows eight‐membered ring channels along a and b axes with a typical GIS topology, and – most importantly – the structure of the inorganic framework is retained when the organic amine is removed by calcination.
Synthesis and Crystal Structures of InGaO3(ZnO)m (m = 2 and 3)
Authors: Keller Isabelle , Assenmacher Wilfried , Schnakenburg Gregor , Mader Werner 
Published: August 2009

AbstractAn optimized high temperature route in sealed platinum tubes was used for synthesis of pure powders of members of the homologues series InGaO3(ZnO)m. Single crystals of InGaO3(ZnO)2 were grown from a K2MoO4 flux. InGaO3(ZnO)2 crystallises in the hexagonal crystal system (P63/mmc; No. 194), deduced from convergent beam electron diffraction (CBED). Single crystal structure refinement from XRD data (a = 3.2909(2) Å; c = 22.485(2) Å; Z = 2; 1603 data, R1 = 0.0237) revealed a compound which consists of an alternate stacking of [InO{}^‐_6/3]{}^\infty_2 and [(Ga,Zn)O{}^+_4/4]{}^\infty_3 corresponding to CdI2 and wurtzite type structure motifs, respectively. Inversions of the ZnO4 tetrahedra occurs (i) at the InO6 octahedral layer and (ii) halfway in the wurtzite type region where the inversion boundary is built by Ga3+ in trigonal bipyramidal coordination with a long Ga–Oapical distance of 2.138 Å. The site occupation of Zn2+ and Ga3+, respectively, was confirmed by valence sum calculations. The structure of InGaO3(ZnO)3 was refined from powder X‐ray diffraction data. InGaO3(ZnO)3 crystallises trigonal (R\bar{3}m; No. 166; a = 3.2871(9) Å; c = 41.589(1) Å, RBragg = 0.0506). The space group was confirmed by CBED. The structure of InGaO3(ZnO)3 is similar to InGaO3(ZnO)2, however, the wurtzite type part of the structure has an even number of closed packed oxygen layers and thus the inversion boundary within this area is different. The compounds described here have the structural charactistics as other known members of general formula (ARO3)&&num;903;(ZnO)m with m = integer.
Charge Disproportionation and Charge Transfer in A‐site Ordered Perovskites Containing Iron
Authors: Shimakawa Yuichi , Takano Mikio 
Published: August 2009

AbstractNew A‐site ordered perovskite structure oxides, CaCu3Fe4O12 and LaCu3Fe4O12, were synthesized under high‐pressure and high‐temperature conditions. The compounds contain unusually high valence states of iron: Fe4+ in CaCu3Fe4O12 and Fe3.75+ in LaCu3Fe4O12. Instabilities of the high oxidation states at low temperatures are resolved in CaCu3Fe4O12 by charge disproportionation from Fe4+ to Fe3+ and Fe5+ and in LaCu3Fe4O12 by charge transfer between A‐site copper and B‐site iron ions. The charge disproportionation and the charge transfer are accompanied by significant changes in structural, transport, and magnetic properties.
Rapid Colonization with Methicillin‐Resistant Coagulase‐Negative Staphylococci After Surgery
Authors: Zingg Walter , Demartines Nicolas , Imhof Alexander , Senn Gabriela , Ruef Christian 
Published: August 2009

AbstractBackgroundAntimicrobial resistance may compromise the efficacy of antibiotic prophylaxis before surgery. The aim of this study was to measure susceptibility and clonal distribution of coagulase‐negative staphylococci (CoNS) colonizing the skin around the surgery access site before and after the procedure.MethodsFrom March to September 2004, a series of 140 patients undergoing elective major abdominal surgery were screened for CoNS colonization at admission and 5 days after surgery. All isolates were tested for antibiotic susceptibility and genotyped by pulsed‐field gel electrophoresis (PFGE).ResultsColonization rates with CoNS at admission and after surgery were 85% and 55%, respectively. The methicillin‐resistant CoNS rate increased from 20% at admission to 47% after surgery (P = 0.001). The PFGE pattern after surgery revealed more patients colonized with identical clones: 8/140 patients (8/119 strains) and 26/140 patients (26/77 strains), respectively (P < 0.001).ConclusionsOur results suggest rapid recolonization of disinfected skin by resistant nosocomial CoNS. Larger studies, preferably among orthopedic or cardiovascular patients, are required to clarify whether standard antibiotic prophylaxis with first‐ or second‐generation cephalosporins for CoNS infections may be compromised if the patient requires an additional intervention 5 days or more after the initial surgery.
Initial Management of Extensive Mesenteric Venous Thrombosis: Retrospective Study of Nine Cases
Authors: Cenedese Alice , Monneuse Olivier , Gruner Laurent , Tissot Etienne , Mennesson Nicolas , Barth Xavier 
Published: August 2009

AbstractBackgroundThe development of mesenteric venous thrombosis (MVT) does not necessarily require surgical intervention. The aim of this study was to assess the efficacy of avoiding early operative intervention, which can lead to significant sacrifice of the small bowel.MethodsPatients with MVT were identified using the inpatient registry for the years between 2003 and 2007. Each patient’s past medical history, history of prior deep venous thrombosis or hypercoagulable state, clinical and biologic presentation, and computed tomography (CT) results were analyzed. The proportion of ischemic bowel observed on the CT scans was compared with the length of the bowel resected.ResultsNine patients were admitted for extensive MVT during the time period evaluated (six men, three women). All CT scans demonstrated signs of severe bowel ischemia, with a mean ischemic bowel proportion of 21% (range 5–45%). Four patients received medical management alone. Five patients underwent surgery. The mean admission time for these patients prior to the operation was 14.8 days (6–36 days). Surgery was required only in cases of intestinal perforation. The mean length of the bowel resections was 33 cm (20–45 cm). At 6 months after admission, none of the patients required parenteral nutrition. The mean follow‐up evaluation period was 27 months (15–38 months). One patient died secondary to amyotrophic lateral sclerosis during the follow‐up.ConclusionsInitial nonsurgical management comprised of inpatient observation on a surgical ward along with systemic anticoagulation must be considered an alternative treatment strategy for MVT. This strategy delays surgery and therefore avoids short bowel syndrome.
Helicopter Evacuation of Trauma Victims in Los Angeles: Does it Improve Survival?
Authors: Talving Peep , Teixeira Pedro G. R. , Barmparas Galinos , DuBose Joseph , Inaba Kenji , Lam Lydia , Demetriades Demetrios 
Published: August 2009

AbstractBackgroundThe purpose of this study was to investigate the relationship between the method of transport after injury and survival among trauma patients admitted to a Level 1 trauma facility in Los Angeles, California.MethodsThe trauma registry of LAC+USC Medical Center was reviewed to identify all injured patients evacuated by emergency medical service (EMS) from the injury scene from 1998 to 2007. The study population was divided into those who were airlifted (HEMS) and those who were transported by ground emergency medical service (GEMS) with transportation time that exceeded 30 minutes (GEMS > 30 minutes).ResultsDuring the 10‐year study period, 1,836 patients were airlifted (helicopters for emergency medical service (HEMS)) and 1,537 patients were ground transported (GEMS > 30 minutes). HEMS patients suffered more frequently a penetrating injury (19% vs. 11%, p < 0.001), presented more often hypotensive to the emergency department (4% vs. 1%, p < 0.001), had more frequently a Glasgow Coma Scale (GCS) ≤ 8 (9% vs. 3%, p < 0.001) and required more often an intubation at the injury scene (1.6% vs. 0.4%, p < 0.001). However, the transportation time and the total prehospital time were significantly shorter for airlifted patients. After multivariable analysis, the difference in mortality between the two transport modalities was not significant (adjusted odds ratio (95% confidence interval, 0.72 (0.22, 2.35); p = 0.596).ConclusionsIn a metropolitan Los Angeles trauma system, EMS helicopter transportation of injured patients does not appear to improve overall adjusted survival after injury. There is however a potential benefit for severely injured subgroups of patients due to the shorter prehospital times.
Doppler Ultrasound Could Predict Varices Progression and Rebleeding After Portal Hypertension Surgery: Lessons from 146 EGDS and 10 Years of Follow‐Up
Authors: Ferreira Fabio Gonçalves , Ribeiro Maurício Alves , de Fátima Santos Maria , Assef José César , Szutan Luiz Arnaldo 
Published: August 2009

AbstractBackgroundSurgical treatment of variceal hemorrhagic complications for patients with schistosomal portal hypertension in our group comprised an esophagogastric devascularization procedure with splenectomy (EGDS). There are two different kinds of postoperative follow‐up: prophylactic or on‐demand endoscopic program of varices eradication. This program implies risks and costs and only proves necessary in 6–29% of cases. This study was designed to assess portal vein Doppler ultrasound data in these patients, and to verify correlations with progression in the number and size of varices, as well as the appearance of red spots and rebleeding during the postoperative period after EGDS.MethodsData on portal vein Doppler ultrasound from 146 patients with schistosomal portal hypertension and previous history of upper digestive bleeding due to esophagogastric varices rupture was analyzed. All subjects underwent EGDS and were analyzed before and after the procedure and compared postoperatively at four time points: 1 year, 2 years, up to 5 years, and up to 10 years. The following portal hemodynamic parameters were analyzed: diameter and mean blood flow velocity. Variceal size and number, presence of red spots, and rebleeding were all determined by endoscopic examination. Patients were divided into two groups at the each of the four time points, according to esophagogastric varices progression.ResultsPatients with variceal progression had significantly higher values of portal blood flow velocity. At time points I, II, III, and IV, the measured flow velocity from first postoperative year was 17.64 ± 4.84 vs. 13.81 ± 5.61 (p = 0.025); 16.74 ± 4.8 vs. 13.75 ± 5.8 (p = 0.039); 16.01 ± 5.00 vs. 13.23 ± 5.86 (p = 0.036); and 16.01 ± 5.00 vs. 13.23 ± 5.86 (p = 0.036), respectively.ConclusionsPatients with schistosomal portal hypertension submitted to EGDS who had portal blood flow velocity >15.5 cm per second at the first postoperative year ha d progression of esophagogastric varices and a greater chance of rebleeding and, therefore, should be included in the endoscopic program for varices eradication.
SDS-PAGE-Based Quantitative Assay for Screening of Kidney Stone Disease
Authors: Wai-Hoe Lau , Wing-Seng Leong , Ismail Zhari , Lay-Harn Gam 
Published: August 2009

AbstractKidney stone disease is a common health problem in industrialised nations. We developed a SDS-PAGE-based method to quantify Tamm Horsfall glycoprotein (THP) for screening of kidney stone disease. Urinary proteins were extracted by using ammonium sulphate precipitation at 0.27 g salt/mL urine. The resulted pellet was dissolved in TSE buffer. Ten microliters of the urinary proteins extract was loaded and separated on 10% SDS-PAGE under reducing condition. THP migrated as single band in SDS-PAGE. The assay reproducibility and repeatability were 4.8% CV and 2.6% CV, respectively. A total of 117 healthy subjects and 58 stone patients were tested using this assay, and a distinct cut-off (P< 0.05) at 5.6 μg/mL THP concentration was used to distinguish stone patients from healthy subjects. The sensitivity and specificity of the method were 92.3% and 83.3%, respectively.