bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular homochirality and the parity‐violating energy difference. A critique with new proposals
Authors: Chandrasekhar Sosale
Published: December 2007

Previous proposals for the origin of molecular homochirality, based on the effect of the weak neutral current (WNC) on enantiomers, and the amplification of the resultant parity‐violating energy difference (PVED), are possibly flawed. The additive amplification of PVED in crystals and polymers (“Yamagata hypothesis”) cannot lead to detectable levels of optical activity, the original theory apparently overestimating PVED by a factor equal to Avogadro's number. An alternative theory based on the irreversible and spontaneous evolution of a dynamically fluctuating system is apparently impractical. However, the nonlinear amplification of PVED via autocatalytic polymerization may be possible as indicated by a simplified physico‐chemical approach. This may also occur during crystallization and melting, and form the basis of the second order asymmetric transformation. (Thus, reported differences in the melting points of enantiomers in several cases may well be real). Also, the preponderance of racemic compounds over conglomerates may be based on the destabilization of the conglomerate by the action of the WNC on the crystalline lattice. The WNC may also be involved in the anomalous scattering of X‐rays, which possibly arises from their circular polarization: the current theory would need to be revised accordingly. Chirality, 2008. © 2007 Wiley‐Liss, Inc.
Resource allocation for statistical quality of service provision in buffered crossbar switches
Authors: Duan Qiang , Daigle John N.
Published: December 2007

The buffered crossbar switch is a promising switching architecture that plays a crucial role for providing quality of service (QoS) in computer networks. Sufficient amount of resources—bandwidth and buffer space—must be allocated in buffered crossbar switches for QoS provision. Resource allocation based on deterministic QoS objectives might be too conservative in practical network operations. To improve resource utilization in buffered crossbar switches, we study the problem of resource allocation for statistical QoS provision in this paper. First, we develop a model and techniques for analyzing the probabilistic delay performance of buffered crossbar switches, which is described by the delay upper bound with a prescribed violation probability. Then, we determine the required amounts of bandwidth and buffer space to achieve the probabilistic delay objectives for different traffic classes in buffered crossbar switches. In our analysis, we apply the effective arrival envelope to specify traffic load in a statistical manner and characterize switch service capacity by using the service curve technique. Instead of just focusing on one specific type of scheduler, the model and techniques developed in this paper are very flexible and can be used for analyzing buffered crossbar switches with a wide variety of scheduling algorithms. Copyright © 2007 John Wiley & Sons, Ltd.
Temporal–spatial ablation of neural crest in the mouse results in cardiovascular defects
Authors: Porras Diego , Brown Christopher B.
Published: December 2007

Neural crest cells are thought to play a critical role in human conotruncal morphogenesis and dysmorphogenesis. Much of our understanding of the contribution of neural crest to cardiovascular patterning comes from ablation and transplantation experiments in avian species. Although fate mapping experiments in mice suggests a conservation of function, the functional requirement for neural crest in cardiovascular development in mammals has not been formally tested. We used a novel two component genetic system for the temporal–spatial ablation of neural crest in the mouse. Affected embryos displayed a spectrum of cardiovascular outflow tract defects and aortic arch patterning abnormalities. We show that the severity of the cardiovascular phenotype is directly related to the level and extent of neural crest ablation. This is the first report of cardiac neural crest ablation in mammals, and it provides important insight into the role of the mammalian neural crest during cardiovascular development. Developmental Dynamics 237:153–162, 2008. © 2007 Wiley‐Liss, Inc.
Biological spacetime and the temporal integration of functional modules: A case study of dento–gnathic developmental timing
Authors: Boughner Julia C. , Hallgrímsson Benedikt
Published: December 2007

For the individual, coordination between tooth and jaw development is important to proper food acquisition and ingestion later in life. Among and within species, variation in dental and gnathic size, shape, and, in the case of teeth, number, must be mutually accommodating and functionally compatible. For these reasons, the development and evolution of these two systems should be closely integrated. Furthermore, the timing of dental development correlates tightly with life history events such as weaning. This correlation hints at a central regulation of the developmental timing of multiple systems that have tandem effects on physiology and behaviour. Important work on embryonic oral development continues to tease apart the molecular mechanisms that pattern jaw identity and establish tooth morphology and position in the alveolar bone. Still very poorly understood is what underlies rates and periods of gene activity such that pre‐ and postnatal tooth and jaw development are coordinated. Recent literature suggests at least some level of autonomy between permanent tooth and mandibular ontogenetic timing. However, whether the timing of these various signaling pathways is directly regulated or is an outcome of the pathways themselves is untested. Here, we review what is currently known about the embryonic signaling pathways that regulate tooth and jaw development in the context of time rather than space, as has been traditional. We hypothesize that the timing of mandibular and dental development is not directly mediated by a common factor but is an indirect outcome of strong selection for coordinated molecular pathways and growth trajectories. The mandible and lower jaw dentition is a powerful model with which to investigate the mechanisms that facilitate morphological change—in this case, the development and evolution—of organs that are closely integrated in terms of function, space and time. Developmental Dynamics 237:1–17, 2008. © 2007 Wiley‐Liss, Inc.
From Interwoven to Noninterpenetration: Crystal Structural Motifs of Two New Manganese–Organic Frameworks Mediated by the Substituted Group of the Bridging Ligand
Authors: Fu Zhiyong , Yi Jianglong , Chen Yuan , Liao Shijun , Guo Ning , Dai Jingcao , Yang Guodong , Lian Yunxia , Wu Xintao
Published: December 2007

The respective reactions of the MnII ion with the homologous ligands 2‐aminoterephthalic acid and terephthalic acid afforded two novel manganese–organic compounds, [Mn(2‐atp)(bipy‐eta)0.5]n (1) and {[Mn(tp)(bipy‐eta)1.5]·2H2O}n (2). These two compounds were characterized by IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction. Compound 1 (C14H11MnN2O4) belongs to the monoclinic C2 space group, Z = 4 [a = 11.9355(9) Å, b = 15.522(1) Å, c = 7.9542(6) Å, β = 112.591(2)°], whereas compound 2 (C26H26MnN3O6) belongs to the monoclinic P21/c space group, Z = 4 [a = 10.0330(3) Å, b = 11.9454(1) Å, c = 21.8640(5) Å, β = 92.842(2)°]. Both compounds have bimetallic blocks as basic units. With two bridging carboxylate groups, the Mn···Mn separation in compound 2 is 4.841 Å. By contrast, the distance of the Mn···Mn centers in compound 1 (with the first paddle‐like manganese core) is shortened to 3.058 Å by the bridging of four carboxylate groups, which suggests the existence of a Mn–Mn single bond. The paddle‐wheel clusters in compound 1 aggregate into a 3D modular framework that interpenetrates in a threefold manner. The binuclear units in 2 extend to a 3D network with a novel bilayer structural motif. The inclusion of the bipy‐eta molecules prevents the structure of 2 from being interwoven, and it thus adopts a noninterpenetrating arrangement. The results indicate that variations in the molecular self‐assembly are influenced by the substituted group in the bridging ligand.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Preparation of Brookite‐Type TiO2/Carbon Nanocomposite Electrodes for Application to Li Ion Batteries
Authors: Lee Du‐Hee , Park Jae‐Gwan , Jin Choi Kyoung , Choi Heon‐Jin , Kim Dong‐Wan
Published: December 2007

The increasing demand for portable energy has generated significant research interest in nanostructured electrode materials, because of their large interfacial contact area with the electrolyte and short path lengths for Li ion transport. To date, titanium dioxide (TiO2) has been widely investigated as an electroactive, Li‐insertion host. However, the lithium reactivity of brookite‐type TiO2 has rarely been addressed compared to the common polymorphs, anatase and rutile, because of the difficulties encountered in obtaining a phase‐pure brookite structure. Herein, we report on the simple synthesis of nanocrystalline brookite‐type TiO2 using titanium trichloride (TiCl3) and urea [(NH2)2CO]. The average size of the particles precipitated at 100 °C was ca. 10 nm. The brookite structure was stable up to 500 °C and was completely transformed to the rutile structure at 900 °C in an O2 atmosphere. We evaluated the electrochemical properties of each TiO2 powder heat‐treated sample at a preset temperature. Hybrid carbon/TiO2 nanocomposites with high conductivity were also fabricated using a stable suspension of multi‐walled carbon nanotubes (MWCNTs) in aqueous suspension with an appropriate surfactant and subsequent precipitation of TiO2. The carbon incorporation clearly improved the capacity retention of TiO2 upon cycling.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Two Photoluminescent Metal–Organic Frameworks Constructed from Cd3(μ3‐OH) Cluster or 1D Zn5(μ3‐OH)2(μ‐OH)2 Chain Units and In Situ Formed Bis(tetrazole)amine Ligands
Authors: Zheng Ling‐Ling , Li Hao‐Xiang , Leng Ji‐Dong , Wang Jing , Tong Ming‐Liang
Published: December 2007

Hydrothermal reactions of CdCl2·2.5H2O or ZnCl2, sodium dicyanamide, and sodium azide yield two interesting photoluminescent coordination polymers, namely, [Cd{Cd3(μ3‐OH)(dcadtzH)3(H2O)6}2] (1) and [Zn5(μ3‐OH)2(μ‐OH)2(dcadtz)2]·2H2O (2) [dcadtzH3 = bis(5‐tetrazolyl)amine], in which triangular [Cd3(μ3‐OH)]5+ cluster subunits in 1 and 1D [Zn5(μ3‐OH)2(μ‐OH)2]n6n+ chain subunits in 2 are linked by in situ generated bis(tetrazole)amine ligands to generate an interesting 2D coordination net and a 3D microporous metal–organic framework, respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Lanthanide Formamidinates as Improved Catalysts for the Tishchenko Reaction
Authors: Zuyls Agustino , Roesky Peter W. , Deacon Glen B. , Konstas Kristina , Junk Peter C.
Published: December 2007

The tris(formamidinato)lanthanum(III) complexes [La(o‐TolForm)3(thf)2] [1; o‐TolForm = N,N′‐bis(o‐tolyl)formamidinate], [La(XylForm)3(thf)] [2; XylForm = N,N′‐bis(2,6‐dimethylphenyl)formamidinate], and [La(EtForm)3] [3, EtForm = N,N′‐bis(2,6‐diethylphenyl)formamidinate] are a new class of precatalysts for the Tishchenko reaction. Their catalytic activity is a result of their high Lewis acidity and the ease with which the ligand spheres can be interchanged. For the dimerization of benzaldehyde to give benzyl benzoate, which is a benchmark reaction, compound 1 is, to the best of our knowledge, the most active catalyst ever reported. On a preparative scale, the reaction can be performed in the absence of solvent. A range of aromatic, heteroaromatic, and aliphatic aldehydes was rapidly converted into the corresponding esters by using catalysts 1–3.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Low‐complexity fuzzy filter‐assisted turbo equalization for dispersive Rayleigh‐fading channels
Authors: Lain Jenn‐Kaie , Kuo Kun‐Huang , Zhang Liao Yuan‐Kai
Published: December 2007

Turbo equalisation (TEQ) is an iterative detection and decoding technique that has been shown to be successful in mitigating the effects of intersymbol interference (ISI) introduced by partial response modems and by dispersive channels. In this paper, we propose a fuzzy filter‐assisted decision‐feedback equaliser (DFE)‐based TEQ scheme that not only is comparable in performance to the Jacobian radial basis function (RBF) DFE‐based TEQ but also is low‐complexity. The per iteration computation of both the fuzzy filter DFE TEQ using product inference and maximum defuzzification and the fuzzy filter DFE TEQ using minimum inference and maximum defuzzification is much lower than that of the Jacobian RBF DFE TEQ for binary phase‐shift keying (BPSK) modulation, 4 quadrature amplitude modulation (QAM), and 16 QAM. Notably, the computational complexity of the Jacobian RBF DFE TEQ is exponentially related to the feedforward order, but the fuzzy filter DFE TEQ using minimum inference and maximum defuzzification is independent of that. Previous TEQ research has shown that the Jacobian RBF DFE TEQ considerably reduces the computational complexity compared to the logarithmic maximuma posteriori(Log‐MAP) TEQ with similar performance. In this present study, the proposed fuzzy filter DFE TEQ further reduces the computational complexity with slight performance degradation in contrast to the Jacobian RBF DFE TEQ. With this, the materialisation of the TEQ scheme becomes more feasible. Copyright © 2007 John Wiley & Sons, Ltd.
Slot error rate performance of DH‐PIM with symbol retransmission for optical wireless links
Authors: Rajbhandari S. , Ghassemlooy* Z. , Aldibbiat N. M.
Published: December 2007

In this paper we introduce the dual‐header pulse interval modulation (DH‐PIM) technique employing a simple retransmission coupled with a majority decision detection scheme at the receiver. We analytically investigate the slot error rate (SER) performance and compare results with simulated data for the symbol retransmissions rates of three, four and five, showing a good agreement. We demonstrate that the proposed scheme significantly reduces the SER compared with the standard single symbol transmission system, with retransmission rate of five offering the highest code gain of ∼5 dB. Copyright © 2007 John Wiley & Sons, Ltd.
A palynological study of Galium L. (Rubiaceae) in Egypt and its systematic implication
Authors: Abdel Khalik K. , Abd El‐Ghani M. M. , Elkordy A.
Published: December 2007

A pollen morphological investigation of eleven species and one subspecies of the genus Galium L. from Egypt were undertaken by using light microscope (LM) and scanning electron microscope (SEM). Pollen shape, size, exine ornamentation, number of apertures present powerful characters for distinguishing between species. The pollen grains were zonocolpate. The number of colpi ranges from 5 to 10. Their shape varies from prolate spheroidal, oblate spheroidal, spheroidal to suboblate. Three groups can be distinguished based on the size pollen grains. It was found used to distinguish between closely related species G. aparine and G. spurium and between G. tricornutum and G. ceratopodum. Two different types of exine ornamentation were recognized. The ornamentation was found useful to distinguish among closely related species such as Galium aparine and G. spurium. A key for the identification of the investigated taxa based on pollen grains characters is provided. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of comorbidity and cognitive status on instrumental activities of daily living in amnestic mild cognitive impairment: results from the ReGAl project
Authors: Mariani E. , Monastero R. , Ercolani S. , Rinaldi P. , Mangialasche F. , Costanzi E. , Vitale D. F. , Senin U. , Mecocci P.
Published: December 2007

Objectives

To investigate whether amnestic mild cognitive impairment (aMCI) is characterised by restriction in instrumental activities of daily living (IADL). Further, to examine the role of comorbidity and cognitive performance on IADL changes in aMCI subjects.

Methods

The study included 132 subjects with aMCI and 249 subjects with no cognitive impairment (NCI), consecutively enrolled as outpatients in a multicentric Italian clinical‐based study, the ReGAl Project. All subjects underwent a comprehensive evaluation including clinical examination, laboratory screening, neuroimaging and cognitive and behavioral assessments. Functional status was evaluated by the Lawton's Instrumental Activities of Daily Living (IADL) scale. Comorbidity was evaluated by the Cumulative Illness Rating Scale (CIRS). Cognitive evaluation included tests assessing episodic memory, language, attention/executive functioning and praxis, as well as the the Mini‐Mental State Examination (MMSE) as a measure of global cogniton.

Results

Subjects with aMCI had higher IADL changes than NCI. Among IADL items, aMCI subjects showed a significant impairment in shopping, taking drugs, and handling economy; however also NCI had minor IADL changes regarding cooking, washing and cleaning. IADL restriction in aMCI subjects was significantly associated with cognitive performance, mainly related to executive functioning, but not with comorbidity. On the contrary, in NCI sensory impairment accounts for slight IADL changes.

Conclusion

In aMCI subjects a mild degree of cognitive deterioration has a stronger impact on IADL than somatic comorbidity. Current diagnostic criteria for MCI should include a mild impairment in IADL. Copyright © 2007 John Wiley & Sons, Ltd.
Medication errors in older people with mental health problems: a review
Authors: Maidment Ian D , Haw Camilla , Stubbs Jean , Fox Chris , Katona Cornelius , Franklin Bryony Dean
Published: December 2007

Objective

To review and summarise published data on medication errors in older people with mental health problems.

Methods

A systematic review was conducted to identify studies that investigated medication errors in older people with mental health problems. MEDLINE, EMBASE, PHARMLINE, COCHRANE COLLABORATION and PsycINFO were searched electronically. Any studies identified were scrutinized for further references. The title, abstract or full text was systematically reviewed for relevance.

Results

Data were extracted from eight studies. In total, information about 728 errors (459 administration, 248 prescribing, 7 dispensing, 12 transcribing, 2 unclassified) was available. The dataset related almost exclusively to inpatients, frequently involved non‐psychotropics, and the majority of the errors were not serious.

Conclusions

Due to methodology issues it was impossible to calculate overall error rates. Future research should concentrate on serious errors within community settings, and clarify potential risk factors. Copyright © 2007 John Wiley & Sons, Ltd.
Improvement in behavioural symptoms in patients with moderate to severe Alzheimer's disease by memantine: a pooled data analysis
Authors: Gauthier S. , Loft H. , Cummings J.
Published: December 2007

Introduction

Behavioural disturbances are a common and distressing aspect of Alzheimer's disease (AD). This pooled analysis evaluated the specific benefits of memantine on behavioural disturbances in patients with moderate to severe AD.

Methods

Data were pooled from six 24/28‐week, randomised, placebo‐controlled, double‐blind studies. Of the 2,311 patients included in these studies, 1,826 patients with moderate to severe AD (MMSE <20) were included in this analysis, corresponding to the extended indication for memantine in Europe. In this subgroup, 959 patients received memantine 20 mg/day and 867 received placebo. Behavioural symptoms were rated using the Neuropsychiatric Inventory (NPI) total and single‐item scores at weeks 12 and 24/28.

Results

At weeks 12 and 24/28, ITT analysis demonstrated that memantine treatment produced statistically significant benefits over placebo treatment in NPI total score (p = 0.001 and p = 0.008), and in NPI single items: delusions (p = 0.007 week 12, p = 0.001 week 24/28), hallucinations (p = 0.037 week 12), agitation/aggression (p = 0.001 week 12, p = 0.001 week 24/28), and irritability/lability (p = 0.005 week 24/28), LOCF population. Analysis of the patients without symptoms at baseline indicated reduced emergence of agitation/aggression (p = 0.002), delusions (p = 0.047), and disinhibition (p = 0.011), at week 12, and of agitation/aggression (p = 0.002), irritability/lability (p = 0.004), and night‐time behaviour (p = 0.050) at week 24/28 in those receiving memantine. OC analyses yielded similar results.

Conclusions

The data suggest that memantine is effective in treating and preventing the behavioural symptoms of moderate to severe AD. Specific persistent benefits were observed on the symptoms of delusions and agitation/aggression, which are known to be associated with rapid disease progression, increased caregiver burden, early institutionalisation, and increased costs of care. Copyright © 2007 John Wiley & Sons, Ltd.
High‐dose escitalopram in the treatment of binge‐eating disorder with obesity: a placebo‐controlled monotherapy trial
Authors: Guerdjikova Anna I. , McElroy Susan L. , Kotwal Renu , Welge Jeffrey A. , Nelson Erik , Lake Katie , Alessio David D' , Keck Paul E. , Hudson James I.
Published: December 2007

Objective

The purpose of this study was to evaluate the efficacy and safety of high‐dose escitalopram in the treatment of binge‐eating disorder (BED) associated with obesity.

Method

Forty‐four outpatients with BED by DSM‐IV criteria and obesity were randomized to receive either escitalopram (N = 21) or placebo (N = 23) in a 12‐week, double‐blind, flexible dose (10–30 mg/day) study.

Results

In the primary analysis, escitalopram (mean dose 26.5 mg/day) and placebo had similar rates of reduction of binge episodes, binge days and obsessive‐compulsive symptoms of BED. However, escitalopram was associated with statistically significant reductions in weight, body mass index (BMI), and global severity of illness scores. In a secondary analysis, escitalopram was associated with statistically significant reductions in frequency of binge episodes and binge days, weight, BMI and severity of illness, but not in obsessive‐compulsive symptoms of BED. No changes in metabolic variables, including measures of ghrelin and leptin, were observed. High‐dose escitalopram was well tolerated.

Conclusion

High‐dose escitalopram was not efficacious in reducing obsessive‐compulsive symptoms of BED, but was efficacious in reducing weight and global severity of illness. No definitive conclusions about its efficacy in reducing binge‐eating frequency could be drawn due to limitations related to statistical power. Copyright © 2007 John Wiley & Sons, Ltd.
Measuring effectiveness of three postfire hillslope erosion barrier treatments, western Montana, USA
Authors: Robichaud Peter R. , Pierson Frederick B. , Brown Robert E. , Wagenbrenner Joseph W.
Published: December 2007

After the Valley Complex Fire burned 86 000 ha in western Montana in 2000, two studies were conducted to determine the effectiveness of contour‐felled log, straw wattle, and hand‐dug contour trench erosion barriers in mitigating postfire runoff and erosion. Sixteen plots were located across a steep, severely burned slope, with a single barrier installed in 12 plots (four per treatment) and four plots left untreated as controls. In a rainfall‐plus‐inflow simulation, 26 mm h−1 rainfall was applied to each plot for 1 h and 48 L min−1 of overland flow was added for the last 15 min. Total runoff from the contour‐felled log (0·58 mm) and straw wattle (0·40 mm) plots was significantly less than from the control plots (2·0 mm), but the contour trench plots (1·3 mm) showed no difference. The total sediment yield from the straw wattle plots (0·21 Mg ha−1) was significantly less than the control plots (2·2 Mg ha−1); the sediment yields in the contour‐felled log plots (0·58 Mg ha−1) and the contour trench plots (2·5 Mg ha−1) were not significantly different.

After the simulations, sediment fences were installed to trap sediment eroded by natural rainfall. During the subsequent 3 years, sediment yields from individual events increased significantly with increasing 10 min maximum intensity and rainfall amounts. High‐intensity rainfall occurred early in the study and the erosion barriers were filled with sediment. There were no significant differences in event or annual sediment yields among treated and control plots. In 2001, the overall mean annual sediment yield was 21 Mg ha−1; this value declined significantly to 0·6 Mg ha−1 in 2002 and 0·2 Mg ha−1 in 2003. The erosion barrier sediment storage used was less than the total available storage capacity; runoff and sediment were observed going over the top and around the ends of the barriers even when the barriers were less than half filled. Published in 2007 by John Wiley & Sons, Ltd.
Comparisons of the Colonisation by Invertebrates of Three Species of Wood, Alder Leaves, and Plastic “Leaves” in a Temperate Stream
Authors: Hofer Nancy , Richardson John S.
Published: December 2007

Small woody debris in streams is abundant, and may be a food source or may provide a substrate on which other food sources such as biofilm may develop, both of which may be significant to invertebrates in times of food scarcity. We examined patterns of invertebrate colonisation of small woody debris (veneers of red alder, Douglas‐fir, and western red cedar), red alder leaves, and plastic (as an inert substrate to mimic leaves). Invertebrate colonisation was high on alder leaves, but low on wood substrates and plastic, controlling for the available surface area. Detritivorous invertebrates had significantly higher colonisation rates of alder leaves versus the other four substrates, whereas predators and collectors did not (consistent with their use of these as substrates and not food). All wood decreased in mass by <15% and leaves by ∼50% over the 75 days of the experiment. For all taxa tested, there was no significant difference in their colonisation of the wood veneers versus the plastic sheets. These results suggest that wood was not directly used by these invertebrates as a food source, or that there could be similar biofilm development on the surfaces of these substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Repeatability of Fish Biomass and Size Distribution Estimates Obtained by Hydroacoustic Surveys Using Various Sampling Strategies and Statistical Analyses
Authors: Guillard Jean , Vergès Charlotte
Published: December 2007

Successive hydroacoustic surveys were conducted on a small lake in the Jura Mountains (eastern France) to test several sampling strategies and methods of calculation. The results show that night samples give a better picture of the fish populations than daytime ones; that parallel transect surveys are the ones easiest to conduct, and that, all the survey designs tested, gave statistically equivalent biomass estimations and size distributions. The results obtained are also similar for all the statistical calculation methods used. Repeated samplings on several successive days gave similar results for the estimated biomass and fish size structure in the hypolimnion, but gave different results for the fish populations in the epilimnion. As part of the Water Framework Directive monitoring of fish populations, these hydroacoustic methods can be used to estimate fish stocks, and to track their change over time and spatial differences, but they need to be combined with complementary sampling methods. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Capillary electrophoresis evidence of the stereoselective ketoreduction of mebendazole and aminomebendazole in echinococcosis patients
Authors: Theurillat Regula , Thormann Wolfgang
Published: December 2007

An assay for the simultaneous determination of the enantiomers of hydroxymebendazole (OH‐MBZ) and hydroxyaminomebendazole (OH‐AMBZ) together with aminomebendazole (AMBZ) in human plasma is described for the first time. It is based upon liquid–liquid extraction at alkaline pH from 0.5 mL plasma followed by analysis of the reconstituted extract by CE with reversed polarity in the presence of a 50 mM, pH 4.2 acetate buffer containing 15 mg/mL sulfated β‐CD as chiral selector. For all compounds, detection limits are between 0.01 and 0.04 μg/mL, and intraday and interday precisions evaluated from peak area ratios are <6.9 and <8.5%, respectively. Analysis of 39 samples of echinoccocosis patients undergoing pharmacotherapy with mebendazole (MBZ) revealed that the ketoreduction of MBZ and AMBZ is highly stereoselective. One enantiomer of each metabolite (firstly detected peak in both cases) could only be detected. The CE data revealed that OH‐MBZ (mean: 0.715 μg/mL) is the major metabolite followed by AMBZ (mean: 0.165 μg/mL) and OH‐AMBZ (mean: 0.055 μg/mL) whereas the MBZ plasma levels (mean: 0.096 μg/mL, levels determined by HPLC) were between those of AMBZ and OH‐AMBZ.
Rapid and sensitive determination of acrylamide in drinking water by planar chromatography and fluorescence detection after derivatization with dansulfinic acid
Authors: Alpmann Alexander , Morlock Gertrud
Published: December 2007

On the basis of a novel derivatization, a new planar chromatographic method has been developed for the determination of acrylamide (AA) in drinking water at the ultra‐trace level. After SPE, the water extracts were oversprayed on a high‐performance thin‐layer chromatography (HPTLC) silica gel plate with the derivatization agent dansulfinic acid and derivatized in situ. Chromatography was performed with ethyl acetate and the fluorescent product was quantified at 366/>400 nm. Verification was based on HPTLC‐ESI/MS, HPTLC‐direct analysis in real‐time (DART)‐TOF/MS and NMR. The routine HPTLC‐fluorescence detection (FLD) method was validated for spiked drinking water. The regression analysis was linear (r >0.9918) in the range of 0.1–0.4 μg/L. LOD was calculated to be 0.025 μg/L and experimentally proved for spiked samples at levels down to 0.05 μg/L (S/N = 6) which was suited for monitoring the EU limit value of 0.1 μg/L in drinking water (0.5 μg/L demanded by World Health Organization (WHO)/US Environmental Protection Agency (EPA)). Within‐run precision and the mean between‐run precision (RSD, n = 3, three concentration levels each) were evaluated to be 4.8 and 11.0%, respectively. The mean recovery (0.1, 0.2, and 0.3 μg/L) was 96% corrected by the internal standard. The method, in comparison with HPLC‐MS/MS showed comparable results and demonstrated the accuracy of the method.
Dietary intake and risk evaluation of polybrominated diphenyl ethers in The Netherlands
Authors: Bakker Martine I. , de Winter‐Sorkina Renata , de Mul Anika , Boon Polly E. , van Donkersgoed Gerda , van Klaveren Jacob D. , Baumann Bert A. , Hijman Willie C. , van Leeuwen Stefan P. J. , de Boer Jacob , Zeilmaker Marco J.
Published: December 2007

The current study aims at estimating the dietary intake of PBDEs in the Netherlands and evaluating the resultant risk. Dietary intake was estimated using results of PBDE analyses in Dutch food products from 2003/2004 and consumption data of the third Dutch National Food Consumption Survey (1997/1998). Assuming that non‐detects represent levels of half the detection limit, the median long‐term intake of the Dutch population of the sum of five major PBDEs (namely PBDEs 47, 99, 100, 153+154) is 0.79 ng/kg body weight bw/day (P97.5: 1.62 ng/kg bw/day). When non‐detects are considered as zeros the values are 0.53 (median) and 1.34 (P97.5) ng/kg bw/day. Environmental concentrations of PBDEs in Europe are expected to decline in the near future because of the ban on penta‐ and octaBDE technical products. However, it will take at least a decade before this will result in lower PBDE concentrations in food products. Hence, a regular monitoring program for PBDEs is recommended. A risk evaluation at the most sensitive endpoints of BDE 99 carried out in this paper indicates that, although the long‐term exposure to BDE 99 is well below the human exposure threshold level for neurodevelopmental toxicity, it may be close to that for reproductive toxicity.
Ambulance location for maximum survival
Authors: Erkut Erhan , Ingolfsson Armann , Erdoğan Güneş
Published: December 2007

This article proposes new location models for emergency medical service stations. The models are generated by incorporating a survival function into existing covering models. A survival function is a monotonically decreasing function of the response time of an emergency medical service (EMS) vehicle to a patient that returns the probability of survival for the patient. The survival function allows for the calculation of tangible outcome measures—the expected number of survivors in case of cardiac arrests. The survival‐maximizing location models are better suited for EMS location than the covering models which do not adequately differentiate between consequences of different response times. We demonstrate empirically the superiority of the survival‐maximizing models using data from the Edmonton EMS system. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2008
Incidence of cardiovascular events in breast cancer patients receiving chemotherapy in clinical practice
Authors: Sukel Myrthe P. P. , Breekveldt‐Postma Nancy S. , Erkens Joëlle A. , van der Linden Paul D. , Beiderbeck Annette B. , Coebergh Jan Willem W. , Herings Ron M. C.
Published: December 2007

Purpose

To assess the incidence of cardiovascular events among breast cancer patients after chemotherapy.

Methods

Women ≥18 years with a breast tumour who received chemotherapy in 1992–2003 were selected from the PHARMO RLS. Chemotherapy with anthracyclines, a combination of anthracyclines and taxanes or second line treatment with trastuzumab was classified as cardiotoxic. Cardiovascular events were determined based on drug use and hospital admissions. Incidence rates of cardiovascular events and hazard ratios (HR) for the cardiotoxic versus non‐cardiotoxic chemotherapy group were assessed during the first year and total follow‐up.

Results

Of 648 patients with breast cancer included in the study cohort, 353 (54%) received cardiotoxic chemotherapy. At baseline, patients who received cardiotoxic chemotherapy compared with patients receiving non‐cardiotoxic chemotherapy, received less anticoagulants/haemostatics (5 vs. 11%; p = 0.012) and had been less often hospitalised for cardiovascular disease (1 vs. 5%; p = 0.007) 2 years before the cohort entry date. After 1‐year follow‐up, the incidence rate of cardiovascular events was 69/1000 person years (py) for patients with cardiotoxic chemotherapy and 98/1000 py for patients with non‐cardiotoxic chemotherapy, which did not differ significantly (HR 0.74 95% confidence interval (CI): 0.39, 1.41). After total follow‐up, this was 81/1000 py for patients with cardiotoxic and 92/1000 py for patients with non‐cardiotoxic chemotherapy (HR 0.81, 95%CI: 0.54, 1.20).

Conclusions

This study showed similar cardiovascular incidence rates during follow‐up for breast cancer patients treated with cardiotoxic and non‐cardiotoxic chemotherapy. Specialists seemed to take pre‐existing cardiovascular diseases into account when treating the breast cancer patient. Copyright © 2007 John Wiley & Sons, Ltd.
Five years of operating experience at a large, utility‐scale photovoltaic generating plant
Authors: Moore L. M. , Post H. N.
Published: December 2007

Tucson Electric Power Company (TEP), headquartered in Tucson, AZ, currently has nearly 5·0 MWdc of utility‐scale grid‐connected photovoltaic (PV) systems installed in its service territory. These systems have been installed through a multiyear, pay‐as‐you‐go development of renewable energy, with kWhac energy production as a key program measurement. This PV capacity includes a total of 26 crystalline silicon collector systems, each rated at 135 kWdc for a total of 3·51 MWdc, that have been installed at the Springerville, AZ generating plant by TEP making this one of the largest PV plants in the world. This facility started operations in 2001 and recently passed the 5‐year milestone of continuous operations. These systems were installed in a standardized, cookie‐cutter approach whereby each uses the same array field design, mounting hardware, electrical interconnection, and inverter unit. This approach has allowed TEP to achieve a total installed system cost of $5·40/Wdc and a TEP‐calculated levelized energy cost of $0·062/kWhac for PV electrical generation. This paper presents an assessment of operating experience including performance, costs, maintenance, and plant operation over this 5‐year period making this one of the most detailed and complete databases of utility‐scale PV systems available to the US DOE Program. Published in 2007 by John Wiley & Sons, Ltd.
Internal structure and ice content of Reichenkar rock glacier (Stubai Alps, Austria) assessed by geophysical investigations
Authors: Hausmann H. , Krainer K. , Brückl E. , Mostler W.
Published: December 2007

The Reichenkar rock glacier (Tyrol, Austria) is a typical tongue‐shaped, 1400 m long, ice‐cored active rock glacier, which connects to a debris‐free cirque glacier. Aerial photographs from 1954 and 1990 indicate its mean surface velocity to be 0.6 m/a while a photograph from 2003 and annual global positioning system (GPS) measurements since 1998 show that velocities in the past decade have increased to 3 m/a. Integration of ground‐penetrating radar (GPR), seismic and gravimetric data reveals that the Reichenkar rock glacier consists of four layers. The uppermost debris layer has an average thickness of about 5 m and is underlain by ice‐rich permafrost with an average thickness of about 25 m. A prominent reflector detected by GPR is identified as the top of an unfrozen till layer located a few metres above the bedrock. Seismic refraction data clearly indicate the boundary between till and bedrock. The geophysical interpretation shows that the ice‐rich permafrost of the rock glacier has an ice content of 45–60%, depending on assumptions concerning the air content of the ice. Creep velocities calculated from the geophysical model, ice contents and an extension of Glen's flow law are in good accordance with observed surface velocities. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of climate change on runoff in a basin with mountain permafrost, northwest China
Authors: Liu Jingshi , Wang Siyuan , Huang Yuying
Published: December 2007

Trends and variability in basin hydrological regime and climate were analysed for a mountain permafrost catchment in northwest China for the period 1957–2004. The Mann–Kendall non‐parametric test was used to detect trends and the Trend Free Pre‐Whitening approach was employed to correct the time‐series data for autocorrelation. Statistically significant trends for the entire period included strong increases in winter air temperatures and winter monthly flows (December to March). However, change‐point analyses revealed that much of the apparently long‐term trend was actually due to abrupt changes in the variables that mainly occurred in the late 1980s and early 1990s. Copyright © 2007 John Wiley & Sons, Ltd.
Crystal structure of the catalytic trimer of Methanococcus jannaschii aspartate transcarbamoylase
Authors: Vitali Jacqueline , Colaneri Michael J. , Kantrowitz Evan
Published: December 2007

The catalytic trimer of Methanococcus jannaschii aspartate transcarbamoylase is extremely heat stable, maintaining 75% of its activity after heat treatment for 60 min at 75°C. We undertook its structural analysis in order to understand the molecular basis of its thermostability and gain insight on how its catalytic function adapts to high temperature. Several structural elements potentially contributing to thermostability were identified. These include: (i) changes in the amino acid composition such as a decrease in the thermolabile residues Gln and Asn, an increase in the charged residues Lys and Glu, an increase in Tyr and a decrease in Ala residues; (ii) a larger number of salt bridges, in particular, the improvement of ion‐pair networks; (iii) shortening of the N‐terminus and shortening of three loops. An interesting feature of the crystal structure is the association of two crystallographically independent catalytic subunits into a staggered complex with an intertrimer distance of 33.8 Å. The active site appears similar to Escherichia coli. Upon substrate binding, smaller changes in the global orientation of domains and larger conformational changes of the active site residues are expected as compared to E. coli. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Optimizing pKA computation in proteins with pH adapted conformations
Authors: Kieseritzky Gernot , Knapp Ernst‐Walter
Published: December 2007

pKA in proteins are determined by electrostatic energy computations using a small number of optimized protein conformations derived from crystal structures. In these protein conformations hydrogen positions and geometries of salt bridges on the protein surface were determined self‐consistently with the protonation pattern at three pHs (low, ambient, and high). Considering salt bridges at protein surfaces is most relevant, since they open at low and high pH. In the absence of these conformational changes, computed pK of acidic (basic) groups in salt bridges underestimate (overestimate) experimental pK, dramatically. The pK for 15 different proteins with 185 known pK yield an RMSD of 1.12, comparable with two other methods. One of these methods is fully empirical with many adjustable parameters. The other is also based on electrostatic energy computations using many non‐optimized side chain conformers but employs larger dielectric constants at short distances of charge pairs that diminish their electrostatic interactions. These empirical corrections that account implicitly for additional conformational flexibility were needed to describe the energetics of salt bridges appropriately. This is not needed in the present approach. The RMSD of the present approach improves if one considers only strongly shifted pK in contrast to the other methods under these conditions. Our method allows interpreting pK in terms of pH dependent hydrogen bonding pattern and salt bridge geometries. A web service is provided to perform pKA computations. Proteins 2008. © 2007 Wiley‐Liss, Inc.
Transpath: A computational method for locating ion transit pathways through membrane proteins
Authors: Kuang Zhifeng , Liu Anping , Beck Thomas L.
Published: December 2007

The finely tuned structures of membrane channel proteins allow selective passage of ions through the available aqueous pores. To understand channel function, it is crucial to locate the pores and study their physical and chemical properties. Here, we propose a new pore‐searching algorithm (TransPath), which uses the Configurational Bias Monte Carlo (CBMC) method to generate transmembrane trajectories driven by both geometric and electrostatic features. The trajectories are binned into groups determined by a vector distance criterion. From each group, a representative trajectory is selected based on the Rosenbluth weight, and the geometrically optimal path is obtained by simulated annealing. Candidate ion pathways can then be determined by analysis of the radius and potential profiles. The proposed method and its implementation are illustrated using the bacterial KcsA potassium channel as an example. The procedure is then applied to the more complex structures of the bacterial E. coli chloride channel homolog and a homology model of the ClC‐0 channel. Proteins 2008. © 2007 Wiley‐Liss, Inc.
High quality binding modes in docking ligands to proteins
Authors: Gorelik Boris , Goldblum Amiram
Published: December 2007

Multiple near‐optimal conformations of protein‐ligand complexes provide a better chance for accurate representation of biomolecular interactions, compared with a single structure. We present ISE‐dock – a docking program which is based on the iterative stochastic elimination (ISE) algorithm. ISE eliminates values that consistently lead to the worst results, thus optimizing the search for docking poses. It constructs large sets of such poses with no additional computational cost compared with single poses. ISE‐dock is validated using 81 protein‐ligand complexes from the PDB and its performance was compared with those of Glide, GOLD, and AutoDock. ISE‐dock has a better chance than the other three to find more than 60% top single poses under RMSD = 2.0 Å and more than 80% under RMSD = 3.0 Å from experimental. ISE alone produced at least one 3.0 Å or better solutions among the top 20 poses in the entire test set. In 98% of the examined molecules, ISE produced solutions that are closer than 2.0 Å from experimental. Paired t‐tests (PTT) were used throughout to assess the significance of comparisons between the performances of the different programs. ISE‐dock provides more than 100‐fold docking solutions in a similar time frame as LGA in AutoDock. We demonstrate the usefulness of the large near optimal populations of ligand poses by showing a correlation between the docking results and experiments that support multiple binding modes in p38 MAP kinase (Pargellis et al., Nat Struct Biol 2002;9:268‐272] and in Human Transthyretin (Hamilton, Benson, Cell Mol Life Sci 2001;58:1491‐1521). Proteins 2008. © 2007 Wiley‐Liss, Inc.
How to ensure children take their medicines as directed
Authors: Tomlin Steve
Published: December 2007

Our series Prescribing in children gives practical advice for successful management of childhood problems in general practice. Here, the author describes how the problems of compliance with medicines‐taking can be overcome. Copyright © 2007 Wiley Interface Ltd
Evidence for efficient screening in organic materials
Authors: Casu M. B.
Published: December 2007

We present highly resolved X‐ray photoemission measurements performed in order to investigate surface core level shifts (SCLS) on various different organic systems: PTCDA, coronene, and metal free phthalocyanine. C 1s spectra evidence the absence of SCLS in organic thin films. We explained these results in terms of very efficient screening. If the molecular interaction is sufficiently strong, the screening of the created charge by delocalisation is quite efficient. SCLS absence in organic materials implies that polarisation energies are much lower than usually assumed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cost‐effectiveness analysis in colorectal cancer using a semi‐Markov model
Authors: Castelli Christel , Combescure Christophe , Foucher Yohann , Daures Jean‐Pierre
Published: December 2007

Cost and effectiveness are usually modeled according to one studied event or one health state with parametric or non‐parametric methods. In this paper, we propose an original method for assessing total costs while incorporating the dynamics of change in the health status of patients. A semi‐Markov model in which the distributions of sojourn times are explicitly defined is developed. The hazard function of sojourn times is modeled by Weibull distributions specific to each transition. A vector of covariates is incorporated into the hazard function of each transition. From a regression model for costs, a cumulative cost function is derived. An estimation of the mean cost per patient in each state defined in the semi‐Markov model could thus be made, and this enables us to identify the determinants of direct costs. The results of incremental net benefit (INB) are assessed using the bootstrap method. A cost‐effectiveness analysis is performed in order to compare two strategies of follow‐up in the colorectal cancer study. Two hundred and forty patients were enrolled in this study. Three health states are defined for patients with curative resection of colorectal cancer: alive without relapse, alive with relapse, and dead. The mean survival is 4.35 and 4.12 years, respectively, in the standard and moderate follow‐up groups. We show that mean cost differs significantly by follow‐up strategy and Dukes stage. Finally, the INB is assessed and this indicates that neither of the strategies compared was more cost‐effective than the other. Copyright © 2007 John Wiley & Sons, Ltd.