bluuebunny/crossref_metadata_2025 huggingface dataset:
Supramolecular Heterotrimetallic Assembly Based on Octacyanomolybdate, Manganese, and Copper
Authors: Long Jérôme , Chamoreau Lise‐Marie , Marvaud Valérie
Published: September 2011

A unique heterotrimetallic supramolecular assembly has been obtained by following a modular synthetic strategy based on the use of octacyanomolybdate(IV), manganese(III), and copper(II) complexes as building blocks. From a structural standpoint, single‐crystal X‐ray diffraction reveals the presence of the three different metallic centers that are originally arranged in a one‐dimensional fashion. Considering the interchain interaction, the compound is able to be described as a two‐dimensional network made up of Mo–CN–Cu–NC–Mo squares that bear pendant Mn complexes. Despite the presence of the Mo/Cu photomagnetic pair and large uniaxial anisotropy, no long‐lived metastable state was observed upon light irradiation. Nevertheless, the compound led to novel magnetic materials as well as advances in the study of charge‐transfer complexes.
Homopiperazine and Piperazine Complexes of ZrIV and HfIV and Their Application to the Ring‐Opening Polymerisation of Lactide
Authors: Hancock Stuart L. , Mahon Mary F. , Kociok‐Kőhn Gabriele , Jones Matthew D.
Published: September 2011

In this paper we describe the preparation and characterisation, by single‐crystal X‐ray diffraction, of twelve ZrIV/HfIV complexes based on piperazine or homopiperazine salan ligands. With the piperazine ligands, a mixture of species was observed and various solid‐state structures were isolated. However, with homopiperazine salan ligands, 1:1 ligand‐to‐metal complexes were observed both in solution and in the solid state. Interestingly, for the homopiperazine complexes the isopropoxide ligands are trans to one another in the solid state, most likely because of the rigid nature of the homopiperazine backbone. All homopiperazine HfIV and ZrIV complexes were tested for the ring‐opening polymerisation (ROP) of rac‐lactide. The complexes are active and produce polylactide with narrow polydispersity indices. The kinetics and living characteristics of the polymerisation have also been investigated.
Monoanionic N,P,S‐Janus Head Tripods in s‐Block Metal Coordination
Authors: Meinholz Margret M. , Stalke Dietmar
Published: September 2011

Polyimido sulfur phosphanyl complexes of alkaline earth metals can be synthesised by transmetallation of a suitable lithium precursor. By the same route heterobimetallic complexes of lithium, potassium or rubidium are accessible. [(tmeda)Li{Ph2PCH2S(NSiMe3)2}] (I) is an excellent starting material for such reactions because the pendent phosphorus side arm is free to precoordinate with a second metal to bring this metal into close spatial proximity with the ligand's two nitrogen chelating claws. Lithium can then leave the complex as a stable tmeda/ligand adduct. Via this route several alkali and alkaline earth metal complexes such as [M{Ph2PCH2S(NSiMe3)2}2] with M = Ca (1), Sr (2), and [(tmeda)M′{Ph2PCH2S(NSiMe3)2}2Li] with M′ = Rb (3), K (4) were synthesized and structurally characterized. All compounds show interesting structural features both in the solid state and in solution.
Electrochemical conversion of fatty acids
Authors: Schäfer Hans J.
Published: September 2011

Electrochemical conversions combine an electron transfer with a chemical reaction, which allows conversions that are not available in non‐electrochemical reactions. Electrochemical conversions usually need fewer steps, produce less waste, provide a cheaper reagent, require less auxiliaries, and allow often an easier scale‐up than non‐electrochemical syntheses. In addition, they can be conducted at ambient temperature and pressure. All these qualities agree well with the rules of green chemistry. Electroactive sites for fatty acids are the carboxyl group, the CC double bond and the activated CH bond. The deprotonated carboxyl group is anodically decarboxylated to afford an alkyl radical. The radical can couple or add to a CC double bond. Radical coupling provides diesters, pheromones, or C‐glycosides. At the anode the double bond can be substituted in allylic position, add two nucleophiles or can be cleaved. Cathodic reduction of fatty acids with an enone group affords dimer fatty acids in a hydrodimerization. Non‐activated CH bonds in fatty acids can be oxygenated at the anode; the conversion occurs preferentially at the remote CH bonds.
Tetrabenzylhafnium as a New Organometallic Reagent for Imine Addition Resulting in α‐Branched Amines
Authors: Mei Haibo , Ji Xiaoyun , Han Jianlin , Pan Yi
Published: September 2011

Tetrabenzylhafnium has been explored as a new organometallic reagent for the imine addition reaction. This reagent tolerates a wide scope of imines, affording α‐branched amines in excellent yields without the use of any additive or catalyst. This new reagent shows higher efficiency than that observed for classic Grignard and organolithium reagents.
Bis‐Donor–Bis‐Acceptor Tribranched Organic Sensitizers for Dye‐Sensitized Solar Cells
Authors: Abbotto Alessandro , Leandri Valentina , Manfredi Norberto , De Angelis Filippo , Pastore Mariachiara , Yum Jun‐Ho , Nazeeruddin Mohammad K. , Grätzel Michael
Published: September 2011

A new class of tribranched dye‐sensitized solar cell (DSC) sensitizers carrying two conjugated donors and two acceptor/anchoring groups is introduced. The approach leads to significantly different optical properties and enhanced stability with respect to related di‐ and monobranched dyes and yields power conversion efficiencies of up to 5.05 %, which is possibly limited by the computed nonoptimal dye packing on the semiconductor surface.
Enantioselective fungal biotransformation of risperidone in liquid culture medium by capillary electrophoresis and hollow fiber liquid‐phase microextraction
Authors: de Jesus Liana I. , Albuquerque Nayara C. P. , Borges Keyller B. , Simões Rodrigo A. , Calixto Leandro A. , Furtado Niege A. J. C. , de Gaitani Cristiane M. , Pupo Mônica T. , de Oliveira Anderson R. M.
Published: September 2011

Knowing that microbial transformations of compounds play vital roles in the preparation of new derivatives with biological activities, risperidone and its chiral metabolites were determined by capillary electrophoresis and hollow fiber liquid‐phase microextraction after a fungal biotransformation study in liquid culture medium. The analytes were extracted from 1 mL liquid culture medium into 1‐octanol impregnated in the pores of the hollow fiber, and into an acid acceptor solution inside the polypropylene hollow fiber. The electrophoretic separations were carried out in 100 mmol/L sodium phosphate buffer pH 3.0 containing 2.0% w/v sulfated‐α‐CD and carboxymethyl‐β‐CD 0.5% w/v with a constant voltage of −10 kV. The method was linear over the concentration range of 100–5000 ng/mL for risperidone and 50–5000 ng/mL for each metabolite enantiomer. Within‐day and between‐day assay precisions and accuracies for all the analytes were studied at three concentration levels, and the values of relative standard deviation and relative error were lower than 15%. The developed method was applied in a pilot biotransformation study employing risperidone as the substrate and the filamentous fungus Mucor rouxii. This study showed that the filamentous fungus was able to metabolize risperidone enantioselectively into its chiral active metabolite, (−)‐9‐hydroxyrisperidone.
On the error exponent of MIMO‐ARQ system over the fast fading channels
Authors: Ebrahimzad Hamid , Mohammadi Abbas , Khandani Amir K.
Published: September 2011

In this paper, the random coding exponent for fast fading multi‐input multi‐output channel equipped with automatic repeat request (ARQ) protocol is derived. This exponent can be used to express the probability of error as a function of the data rate and codeword length. This measure provides an intuition into a fundamental trade‐off between communication reliability, information rate and delay. This paper shows that using multiple antenna and ARQ techniques are promising tools for communication over fast fading channels. Copyright © 2011 John Wiley & Sons, Ltd.
A PBI‐Sb0.2Sn0.8P2O7‐H3PO4 Composite Membrane for Intermediate Temperature Fuel Cells
Authors: Wu X. , Mamlouk M. , Scott K.
Published: September 2011

Fine particles of a solid proton conductor Sb0.2Sn0.8P2O7 were incorporated in PBI‐H3PO4 membranes with 20 wt.%. In SEM figures, the Sb0.2Sn0.8P2O7 particles exhibited even and uniform distribution in the PBI‐Sb0.2Sn0.8P2O7 membrane. Influences of the immersing time and the concentration of H3PO4 solution for immersion on H3PO4 loading level were investigated. H3PO4 loading level was found an important factor on membrane conductivity. Incorporation of Sb0.2Sn0.8P2O7 in the PBI‐H3PO4 membrane resulted in greater membrane conductivities. In the single cell tests, the peak power density of the membrane electrode assembly (MEA) with the PBI‐Sb0.2Sn0.8P2O7‐H3PO4 membrane was also greater than that of a MEA with PBI‐H3PO4 membrane. One MEA using PBI‐Sb0.2Sn0.8P2O7‐H3PO4 membrane achieved a peak power density of 0.67 W cm–2 at 175 °C with H2/O2 and exhibited satisfactory stability.
ESTIMATING WATER DEMAND AT IRRIGATION SCHEME SCALES USING VARIOUS LEVELS OF KNOWLEDGE: APPLICATIONS IN NORTHERN TUNISIA
Authors: Hanafi S. , Mailhol J. C. , Poussin J. C. , Zairi A.
Published: September 2011

The precise estimation of water demand at large‐scale irrigation perimeters is a key requirement for water management. Most methods for estimating water demand use biophysical models and cropping patterns but do not account for the wide range of actual farming practices. As a result, these methods only allow estimation of theoretical water demand. The objective of this study was to analyze different methods for evaluating irrigation water demands using several levels of knowledge about irrigation perimeters such as crop water requirements, cropping pattern, irrigation techniques, and water application depths (WAD). Most of this knowledge was related to farming practices, which can vary. Farm typology is an appropriate way to account for the variability in farming practices. These methods were applied in an irrigation scheme in northern Tunisia. The perimeter was subdivided into two sectors: the first sector was designed for surface irrigation and the second for sprinkler irrigation. The first method estimated water demand at the scheme scale based on actual cropping patterns and assuming that farmers used the planned irrigation techniques and satisfied plant water requirements (L1). However, the farmers did not use the planned irrigation techniques. Instead, they combined surface, sprinkler, and drip irrigation techniques depending on the crops they were growing.

The second method examined current irrigation techniques using the results of farm typology that provided the areas under each crop irrigation system (L2). The two methods provided a theoretical water demand model at the scheme scale. However, water demand also needed to account for actual WADs (L3). Field surveys were performed to evaluate the WAD of each crop irrigation technique. Methods L1 and L2 showed similar estimations of water demand at the scale of the perimeter, and the savings in water obtained by converting to drip irrigation were balanced by a reduction in sprinkler irrigation due to conversion to surface irrigation. In contrast, the L3 method estimated 50% lower water demand than that provided by L1 or L2, since the supply of water was insufficient. The irrigation network was designed 50 years ago and no longer corresponds to the needs of current farmers. Farm typology was also shown to be a method that accounted for farm diversity; water demand estimated based on typology differed by only 5% from that obtained by summing the needs of individual farms. Copyright © 2011 John Wiley & Sons, Ltd.
Therapeutic apheresis before and after kidney transplantation
Authors: George Sajid M. , Balogun Rasheed A. , Sanoff Scott L.
Published: September 2011

Kidney transplantation is considered the treatment of choice for most individuals with end‐stage kidney disease, as well as the most cost‐effective renal replacement therapy for the health care system that serves them. Immunologic sensitization, defined by the presence of antibodies directed against foreign HLA (or so called, donor specific antibodies, or DSA), is a significant barrier to kidney transplantation. Further, the presence of DSA is associated with an increase in the incidence of antibody‐mediated rejection and decreased graft survival following transplantation. Therapeutic plasma exchange, an extracorporeal therapy directed at removing plasma proteins, including DSA, has proven to be an important part of a comprehensive strategy to minimize the effect of sensitization before, and following kidney transplantation. As such, it offers the promise of increasing access to transplantation, as well as improving outcomes following transplantation. In this concise narrative review, we describe more specifically the benefits of kidney transplantation, the epidemiology of kidney transplantation in the United States, the clinical significance of anti‐HLA antibodies, and the evidence supporting a role for therapeutic plasma exchange before and after kidney transplantation. J. Clin. Apheresis, 2011. © 2011 Wiley‐Liss, Inc.
Extracorporeal photopheresis: How, when, and why
Authors: Ward David M.
Published: September 2011

Extracorporeal photopheresis (ECP) is a well‐tolerated procedure that suppresses T‐lymphocyte activity in a clonally‐specific way. It is an effective therapy that has established indications in the management of cutaneous T‐cell lymphoma, graft‐versus‐host disease and some scenarios of solid‐organ transplant rejection. It is being used increasingly around the world. Its applications are evolving, including exploration of its potential for treating autoimmune diseases where cytotoxic T‐cell‐mediated mechanisms appear to be involved, such as Crohn's disease. This article reviews scientific insights into its mechanism of action on the immune system, details of the clinical procedure, its clinical applications in various diseases, and the current evidence for its efficacy and place in medical therapeutics. J. Clin. Apheresis, 2011. © 2011 Wiley‐Liss, Inc.
Therapeutic apheresis: A review of complications and recommendations for Prevention and management
Authors: Mokrzycki Michele H. , Balogun Rasheed A.
Published: September 2011

Therapeutic apheresis procedures are a form of extracorporeal therapy that use different techniques to separate blood into the different components out of which the part containing the etiological agent in a disease process is discarded and the rest of the components of blood are re‐infused into the patient, frequently with the addition of a replacement fluid or volume. These complex procedures have inherent risks of adverse events and factors that may impact on the incidence these events include the underlying disease state, anticoagulation techniques, replacement fluid type including the volume, issues related to the vascular access used, and the therapeutic apheresis procedure type and technique. We present a representative case based review of common complications of therapeutic apheresis and suggestions about how to prevent or manage these as presented at the 2010 Therapeutic Apheresis Academy. J. Clin. Apheresis, 2011. © 2011 Wiley‐Liss, Inc.
The potential role of plasma exchange as a treatment for bilateral diffuse uveal melanocytic proliferation: A report of two cases
Authors: Jaben Elizabeth A. , Pulido Jose S. , Pittock Sean , Markovic Svetomir , Winters Jeffrey L.
Published: September 2011

Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare paraneoplastic syndrome associated with gynecologic malignancies in women and pancreatic or lung carcinomas in men. The clinical presentation consists of the rapid onset of decreased visual acuity due to bilateral serous retinal detachment and cataracts. Pathologically, there is diffuse uveal thickening and proliferation of uveal melanocytes. The onset of blindness is often rapid, with some patients presenting with blindness. We describe the cases of two women with gynecologic malignancies who were treated with plasma exchange (PE) for BDUMP. After a course of five to seven procedures, their ocular disease stabilized. One patient has maintained her vision more than 1 year following the completion of the course of PE. The other patient, who also received treatment with corticosteroids, in addition to the PE, reported stable vision on telephone follow‐up 9 months after presentation. These cases suggest that PE may be a treatment option in this rare paraneoplastic syndrome which has otherwise been reported to invariably result in vision loss. J. Clin. Apheresis, 2011. © 2011 Wiley Periodicals, Inc.
Comparison of capillary electrophoretic techniques for analysis and characterization of metallothioneins
Authors: Zalewska Marta , Bizoń Anna , Milnerowicz Halina
Published: September 2011

To explore and understand the significance of individual metallothionein isoforms, the methods of their identification are needed. Separation of these isoforms requires a high resolution technique which can exploit very small differences in mass, charge, and hydrophobicity. In this report, three different techniques of CE were analyzed and used for metallothionein separation: detection using capillary gel electrophoresis, capillary zone electrophoresis, and capillary isoelectric focusing. Also, three different metallothionein samples were used from horse kidney, rabbit liver, and human liver. We identified metallothionein isoforms based on the determination of their relative molecular masses, on the charge differences in different pH buffers, and based on the pI value. Methods used in this report allow metallothionein identification, permit to quantify the purity and content of its isoforms, and allow studying its polymerization. This report supports and endorses the increased application of CE methodology in proteomics.
Thyroid tubercle of zuckerkandl: Importance in thyroid surgery
Authors: Sheahan Patrick , Murphy Matthew S.
Published: September 2011

Objective:

The Tubercle of Zuckerkandl (TZ), which is the remant of the lateral thyroid process, is an important anatomic structure that serves as a reliable landmark for the recurrent laryngeal nerve in thyroid surgery. Furthermore, removal of the TZ is critical for the adequate performance of a total thyroidectomy. However, there is little mention of the TZ in surgical textbooks or papers.

Methods:

Prospective observational study of 138 consecutive thyroid surgeries. The presence of the TZ, its size, and relationship to the recurrent laryngeal nerve, were recorded.

Results:

A total of 211 thyroid lobes were included in the study. The TZ was identified in 61.1% of all thyroid lobes. The median size was 8 mm (range = 3–40 mm). A TZ was more commonly identified on the right (69.6%) than on the left side (53.2%) (P = .02). The recurrent laryngeal nerve was found deep to the TZ in 98.4% of cases.

Conclusions:

A TZ is present in the majority of thyroid lobes. Awareness of the TZ is critical in performing an adequate total thyroidectomy, and is very useful as a landmark for the recurrent laryngeal nerve.
Poly‐α‐olefin‐based synthetic lubricants: a short review on various synthetic routes
Authors: Ray Saptarshi , Rao Peddy V. C. , Choudary Nettem V.
Published: September 2011

This paper reviews various synthetic protocols for poly‐α‐olefin (PAO) synthetic lubricant base stocks that have evolved over the years. Apart from conventional Lewis acid catalysts known for the synthesis of poly‐α‐olefins, such as aluminium trichloride and boron trifluoride, several new catalysts such as metallocenes and ionic liquids have been reported by various researchers. With increasing options of catalytic processes available, it is now possible to produce tailor made PAOs and thus control the properties of the end products, such as viscosity and the viscosity index. Although 1‐decene is the most widely used monomer for PAO application, researchers have used a wide range of monomers from 1‐hexene to 1‐tetradecene and internal olefins in some cases. Copyright © 2011 John Wiley & Sons, Ltd.
Visual Interpretation of Kernel‐Based Prediction Models
Authors: Hansen Katja , Baehrens David , Schroeter Timon , Rupp Matthias , Müller Klaus‐Robert
Published: September 2011

Statistical models are frequently used to estimate molecular properties, e.g., to establish quantitative structure‐activity and structure‐property relationships. For such models, interpretability, knowledge of the domain of applicability, and an estimate of confidence in the predictions are essential. We develop and validate a method for the interpretation of kernel‐based prediction models. As a consequence of interpretability, the method helps to assess the domain of applicability of a model, to judge the reliability of a prediction, and to determine relevant molecular features. Increased interpretability also facilitates the acceptance of such models. Our method is based on visualization: For each prediction, the most contributing training samples are computed and visualized. We quantitatively show the effectiveness of our approach by conducting a questionnaire study with 71 participants, resulting in significant improvements of the participants’ ability to distinguish between correct and incorrect predictions of a Gaussian process model for Ames mutagenicity.
Tree and Hashing Data Structures to Speed up Chemical Searches: Analysis and Experiments
Authors: Nasr Ramzi , Kristensen Thomas , Baldi Pierre
Published: September 2011

In many large chemoinformatics database systems, molecules are represented by long binary fingerprint vectors whose components record the presence or absence of particular functional groups or combinatorial features. For a given query molecule, one is interested in retrieving all the molecules in the database with a similarity to the query above a certain threshold. Here we describe a method for speeding up chemical searches in these large databases of small molecules by combining previously developed tree and hashing data structures to prune the search space without any false negatives. More importantly, we provide a mathematical analysis that allows one to predict the level of pruning, and validate the quality of the predictions of the method through simulation experiments.
Operation of series‐connected silicon‐based photovoltaic modules under partial shading conditions
Authors: Mäki Anssi , Valkealahti Seppo , Leppäaho Jari
Published: September 2011

Partial shading has been recognized as a major cause of energy losses in photovoltaic (PV) power generators. Partial shading has severe effects on the electrical characteristics of the PV power generator, because it causes multiple maximum power points (MPPs) to the power‐voltage curve. Multiple maxima complicate MPP tracking, and the tracking algorithms are often unable to detect the global maximum. Considerable amount of available electrical energy may be lost, when a local MPP with low power is tracked instead of the global MPP. In this paper, the electrical characteristics of series‐connected silicon‐based PV modules under various partial shading conditions are studied by using a Matlab/Simulink simulation model. The simulation model consists of 18 series‐connected PV modules, corresponding to a single‐phase grid‐connected PV power generator. The validity of the simulation model has been verified by experimental measurements. The voltage and power characteristics of the PV power generator have been investigated under various system shading and shading strength conditions. The results can be utilized to develop new MPP tracking algorithms and in designing, for example, building integrated PV power generators. Copyright © 2011 John Wiley & Sons, Ltd.
Radiative efficiency of state‐of‐the‐art photovoltaic cells
Authors: Green Martin A.
Published: September 2011

Maximum possible photovoltaic performance is reached when solar cells are 100% radiatively efficient, with different photovoltaic technologies at different stages in their evolution towards this ideal. An external radiative efficiency is defined, which can be unambiguously determined from standard cell efficiency measurements. Comparisons between state‐of‐the‐art devices from the representative cell technologies produce some interesting conclusions. Copyright © 2011 John Wiley & Sons, Ltd.
Self‐efficacy and fear of cancer progression during the year following diagnosis of breast cancer
Authors: Melchior Hanne , Büscher Cathrin , Thorenz Andrea , Grochocka Anna , Koch Uwe , Watzke Birgit
Published: September 2011

Objective

The aim of this study was to investigate fear of disease progression (FoP) during the year following diagnosis of breast cancer and its association with general self‐efficacy (SE).

Methods

In a prospective study, 118 breast cancer patients were recruited shortly after diagnosis disclosure (response rate: 54%) and at 1‐year follow‐up (follow‐up rate: 90%). Participants completed self‐report measures of general self‐efficacy (General Self‐Efficacy Scale) and fear of progression (short form of the Fear of Progression Questionnaire).

Results

Cross‐sectional regression analysis revealed that high FoP is significantly associated with low SE, even when controlling for demographic and medical characteristics (total R² = 0.17). Having children and a relatively short time since diagnosis also significantly predicted higher FoP. Longitudinal analyses showed that FoP decreased significantly over time (p = 0.001; d = 0.25), but a significant decrease was only observed for patients with high initial FoP (p < 0.001; d = 0.74) and not for those with low initial FoP (p = 0.688; d = 0.08). SE was not a significant predictor of FoP at follow‐up when controlling for initial FoP and other patient characteristics (incremental R² = 0.001; p = 0.674; total R² = 0.47). Overall, only initial FoP significantly predicted FoP at follow‐up (p < 0.001; β = 0.671).

Conclusion

Findings that low SE is associated with high FoP can help to improve the treatment of dysfunctional fears in breast cancer patients. As FoP changes only slightly over time, treatment to enhance SE and reduce FoP should be initiated soon after disease disclosure. Copyright © 2011 John Wiley & Sons, Ltd.
A G4MP2 and G4 Theoretical Study into the Thermochemical Properties of Explosophore Substituted Tetrahedranes and Cubanes
Authors: Rayne Sierra , Forest Kaya
Published: September 2011

High level G4MP2/G4 composite theoretical method thermochemical calculations were conducted on the parent tetrahedrane and cubane compounds and a suite of 20 mono‐ and polyfunctionalized derivatives with azo, nitro, and peroxo explosophoric substituents. The novel azo and peroxo derivatives of these Platonic solid hydrocarbons are likely to be local minima on their respective potential energy surfaces, suggesting these compounds may be priority synthetic targets. The high, mass normalized gas phase enthalpies of formation for both the tetrahedranes and cubanes exceed those of well‐established primary (mercury fulminate and lead azide) and secondary (RDX and HMX) explosives by up to an order of magnitude. Other known (TNT, HMX, CL‐20, octanitrocubane) or proposed (aminonitroalkanes and acetylenes, nitroboranes) high energy materials generally have substantially less favorable mass normalized gas phase enthalpies of decomposition than the most promising tetrahedrane or cubane derivatives presented herein.
Benefits of pharmacist prescribing in a primary‐care setting
Authors: Kinsey Jacqui , Bashford James
Published: September 2011

Jacqui Kinsey qualified as a pharmacist nonmedical prescriber in 2008 and has since been working in a medical practice in Stoke‐on‐Trent. She provides two sessions per week, running predominantly hypertension clinics. Jacqui also works four days a week at Keele University as the Prescribing Studies Programme Manager within the School of Pharmacy. Copyright © 2011 Wiley Interface Ltd
Irritable bowel syndrome: guide to diagnosis and current interventions
Authors: Thomas Linzi
Published: September 2011

Irritable bowel syndrome is an often chronic and relapsing condition that can be difficult to diagnose and treat. Our Drug review provides a guide to diagnosis and the available dietary, pharmacological and psychological interventions, followed by sources of further information. Copyright © 2011 Wiley Interface Ltd
The King's Fund: Improving the Quality of Care in General Practice
Authors: Chaplin Steve
Published: September 2011

Steve Chaplin describes the three areas of prescribing where the King's Fund considers there is room for improvement in its recent report on the quality of primary care. Copyright © 2011 Wiley Interface Ltd
Concurrent macrolide and statin – a common interaction
Authors: Spencer Rachel , Serumaga Brian
Published: September 2011

In this series we present a number of prescribing safety indicators developed as part of an RCGP project.1 The evidence base behind each of the indicators is given along with information to illustrate their clinical significance. We provide a ‘real‐life’ audit based on the indicator to show how practices could begin to analyse their own prescribing data. Copyright © 2011 Wiley Interface Ltd
Maximum likelihood estimation of inflation factors on error covariance matrices for ensemble Kalman filter assimilation
Authors: Liang Xiao , Zheng Xiaogu , Zhang Shupeng , Wu Guocan , Dai Yongjiu , Li Yong
Published: September 2011

In the ensemble Kalman filter, the forecast error covariance matrix is estimated as the sampling covariance matrix of the forecast ensemble. However, it is well known that such estimations may be far from the true forecast error covariance matrix. In this paper, an inflation approach on forecast error covariance matrix based on the maximum likelihood estimation theory is developed and compared to an existing time‐dependent inflation method and the best‐tuned constant inflation. Our method was first tested on a 40‐variable Lorenz model using spatially correlated observation errors. Specifically, when the observation error variance is incorrectly specified, our proposed method can simultaneously inflate on both forecast and observation error covariance matrices. We then assessed our approach on the two‐dimensional Shallow Water Equation model with higher state dimensions and a larger correlated observation system. The results confirmed that our method is effective in retrieving the true states and correcting observation error variances. Copyright © 2011 Royal Meteorological Society
Conditional nonlinear optimal perturbations: behaviour during the evolution of cold vortices over northeast China
Authors: Jiang Zhina , Wang Donghai
Published: September 2011

Conditional nonlinear optimal perturbations (CNOPs) are the initial perturbations that acquire the largest nonlinear evolution at the forecast time with some initial constraint condition. These CNOPs are calculated and examined during the development of two cold vortices with a regional mesoscale primitive‐equation model. Computation is carried out over a 48‐hour optimization time interval with a dry total perturbation energy norm. Attention is given to the CNOPs in terms of structure and evolution. For the particular cases studied, it was found that the CNOPs, similar to the first linear singular vectors, exhibit localness, in which the wind, temperature and surface pressure perturbation fields match the thermal wind balance qualitatively. The primary perturbation regions of CNOPs are closely related to the source regions of high potential vorticity corresponding to the cold vortices. What is more, CNOPs have deep baroclinic structures, which extend throughout the whole troposphere. With time, CNOPs increase their spatial size over larger areas and become quasi‐barotropic at the optimization time. In addition, we found that the kinetic energy contributions are much larger than the potential energy contributions to the final perturbation energy. A noteworthy property is that although the dry total energy norm is used to measure the perturbation growth, the moisture perturbation energy appears early on, which is smaller than the kinetic energy but larger than the potential energy in the lower troposphere at the forecast time. The above numerical experiments are helpful for understanding the mechanism of perturbation growth during the formation of cold vortices. Copyright © 2011 Royal Meteorological Society
The use of variable CO2 in the data assimilation of AIRS and IASI radiances
Authors: Engelen R. J. , Bauer P.
Published: September 2011

An important component of the assimilation of radiance observations from the AIRS and IASI satellite instruments is the radiative transfer modelling. Currently, the RTTOV model used in the ECMWF IFS system uses a fixed value for CO2. Neglecting the spatio‐temporal variability of CO2 introduces an error in the simulation of the satellite radiances, which could affect the quality of the analyses and forecasts. The current assumption is that variational bias correction corrects most of this error and therefore minimizes the impact on the forecast scores. This paper investigates the possibility of modelling CO2 within the IFS to improve the radiative transfer modelling. Results show that the required bias correction is significantly reduced when using more realistic CO2 values. The impact on the analysis quality and forecast scores is mostly neutral with some indication of improvement in the Tropics and the stratosphere.
The Normal Probability Plot as a Tool for Understanding Data: A Shape Analysis from the Perspective of Skewness, Kurtosis, and Variability
Authors: Boylan Gregory L. , Cho Byung Rae
Published: September 2011

Continuous quality improvement is an effort to improve the quality of products, processes, or services. A program intended to effectively implement such efforts begins with the collection and analysis of data. The primary purpose of the normal probability plot, which is one of the most frequently used graphical tools by quality practitioners and researchers, is for normality testing; however, the plot offers other valuable insights into data analysis that have rarely been addressed in the research community. This article provides an overview of distributional characteristics in the context of the four sample moments and investigates how variations in these moments affect the normal probability plot, focusing primarily on the presence of skewness and kurtosis and the effects of variability. This article then lays out a comprehensive analysis of how various statistical characteristics within a data set can influence the shape and corresponding properties of a normal probability plot, demonstrating how variations in the characteristics of the data can reveal or mask the degree of concavity, convexity, or the S shape in the plot, as well as the spread of the data about the mean and in the tails. This can provide engineers with a better understanding of the ways in which data “communicate” through the plot, thereby providing a better basis for initial assumptions, as well as facilitating more accurate model estimation and optimization results thereafter. Copyright © 2011 John Wiley & Sons, Ltd.
Design and implementation of grouped rescue robot system using self‐deploy networks
Authors: Kamegawa Tetsushi , Sato Noritaka , Hatayama Michinori , Uo Yojiro , Matsuno Fumitoshi
Published: September 2011

In this study, we propose a new system for searching the inside of a damaged building using grouped rescue robots. Because the assumed target environment is broad and variable, the proposed system is designed to have adaptability, scalability, and usability. The system consists of robots, sensors, a network, a communication protocol, user interfaces, and database management systems; their complementary capabilities allow them to satisfy the requirements for the system. This study presents the requirements and design of the proposed system, briefly describes each element, and provides examples of how the elements function as an integrated system. © 2011 Wiley Periodicals, Inc.
On the association between variables with lower detection limits
Authors: Romdhani Héla , Lakhal‐Chaieb Lajmi
Published: September 2011

In this paper, we define a modified version τb of Kendall's tau to measure the association in a pair (X,Y ) of random variables subject to fixed left censoring due to known lower detection limits. We provide a nonparametric estimator of τb and investigate its asymptotic properties. We then assume an Archimedean copula for (X,Y ) and express τb in terms of the copula parameter α and the censoring fractions. We deduce estimators for α and for the global Kendall's tau. We develop a goodness‐of‐fit test for the assumed copula. We evaluate the finite‐sample performance of the proposed methods by simulations and illustrate their use with a real data set on plasma and saliva viral loads. Copyright © 2011 John Wiley & Sons, Ltd.
Analysis of non‐ignorable missing and left‐censored longitudinal data using a weighted random effects tobit model
Authors: Sattar Abdus , Weissfeld Lisa A. , Molenberghs Geert
Published: September 2011

In a longitudinal study with response data collected during a hospital stay, observations may be missing because of the subject's discharge from the hospital prior to completion of the study or the death of the subject, resulting in non‐ignorable missing data. In addition to non‐ignorable missingness, there is left‐censoring in the response measurements because of the inherent limit of detection. For analyzing non‐ignorable missing and left‐censored longitudinal data, we have proposed to extend the theory of random effects tobit regression model to weighted random effects tobit regression model. The weights are computed on the basis of inverse probability weighted augmented methodology. An extensive simulation study was performed to compare the performance of the proposed model with a number of competitive models. The simulation study shows that the estimates are consistent and that the root mean square errors of the estimates are minimal for the use of augmented inverse probability weights in the random effects tobit model. The proposed method is also applied to the non‐ignorable missing and left‐censored interleukin‐6 biomarker data obtained from the Genetic and Inflammatory Markers of Sepsis study. Copyright © 2011 John Wiley & Sons, Ltd.
Inference for cumulative incidence quantiles via parametric and nonparametric approaches
Authors: Lee Minjung , Fine Jason P.
Published: September 2011

In survival analysis, a point estimate and confidence interval for median survival time have been frequently used to summarize the survival curve. However, such quantile analyses on competing risks data have not been widely investigated. In this paper, we propose parametric inferences for quantiles from the cumulative incidence function and develop parametric confidence intervals for quantiles. In addition, we study a simplified method of inference for the nonparametric approach. We compare the parametric and nonparametric inferences in empirical studies. Simulation studies show that the procedures perform well, with parametric analyses yielding smaller mean square error when the model is not too badly misspecified. We illustrate the methods with data from a breast cancer clinical trial. Copyright © 2011 John Wiley & Sons, Ltd.
A scheme for reliable real‐time messaging with bounded delays
Authors: Kim Kwang‐Hae (Kane) , Qian Jing , Zhang Zhen , Zhou Qian , Moon Kyung‐Deok , Park Jun‐Hee , Park Kwang‐Roh , Kim Doo‐Hyun
Published: September 2011

Network‐based real‐time computing applications that require tightly bounded end‐to‐end delays have been increasing at a steady rate in recent years. A messaging layer that yields tight bounds on the latencies in detecting message losses and enables the application layer to initiate a timely recovery action has thus become highly desirable. In this paper, we present a new reliable real‐time messaging scheme called the Delay‐Bounded Reliable Messaging Scheme (DB‐RMS) that is aimed at meeting such requirements. It is built on top of the User Datagram Protocol sub‐layer. DB‐RMS provides multiple service options, each with different fault detection/recovery capabilities and different costs in terms of the execution overhead. This feature makes DB‐RMS suitable for a variety of applications. In this paper, the DB‐RMS service options and the corresponding support protocols are presented first followed by a formal analysis on the detection and reaction latency bounds under various service options. A messaging layer prototype using DB‐RMS has been implemented. To demonstrate the practice of the DB‐RMS, we implemented a clock synchronization algorithm for 802.11 wireless local area networks on top of the DB‐RMS messaging layer. Performance measurements of the prototype implementation have been taken, and the positive results obtained are also presented. Copyright © 2011 John Wiley & Sons, Ltd.
Influence of Temperature and Time of Austempering Treatment on Mechanical Properties of SAE 9254 Commercial Steel
Authors: Cruz J. A. , Rodrigues T. F. M. , Viana V. D. C. , Abreu H. , Santos D. B.
Published: September 2011

This work describes the steps in the study and development of the high content of C, Si, and Cr in commercial steel with a nanostructured matrix of martensite, bainite and retained austenite. Specimens of this steel were austenitized at 900 °C for 5 min and isothermally heat treated at different times (0.5, 2, 24, 48 h) and temperatures (200, 220, 270  °C). Different mechanical behavior was observed for the samples treated under different conditions due to their microstructural constitution. Specimens treated for 2 h at 200 °C showed lower yield strength of 979 MPa. On the other hand a high tensile strength of 2248 MPa was reached. The sample treated at 270 °C showed higher yield strength of 1363 MPa with the same treatment time. As for the fracture analysis, the brittle fracture mechanism was predominant for the samples treated at 200 °C, while the ductile fracture mechanism was predominant for the samples treated at 270 °C.
Preparation of highly substituted carboxymethyl starch using a twin‐screw extruder
Authors: Bhandari Pratik N. , Hanna Milford A.
Published: September 2011

Carboxymethyl starch was prepared by reacting corn starch with sodium mono chloro acetate (SMCA) in a Brabender TSE‐20 co‐rotating twin screw extruder. The effects of the SMCA/starch ratio (theoretical degrees of substitutions 2.73, 3.62, and 4.53), aqueous ethanol/(starch + SMCA) ratio (0.13 and 0.25) and the screw configuration (0, 1, and 2 kneading blocks) on the degree of substitution (DS) and reaction efficiency were studied. A 3 × 2 factorial design with 3 levels of the starch/SMCA ratio and 2 levels of the aqueous ethanol/(starch + SMCA) ratio were used. This 3 × 2 factorial design was blocked, with the screw configuration as the blocking variable. The effects of the SMCA/starch ratio and the screw configuration were found to be significant. The carboxymethylated starches were characterized using FTIR, SEM, and XRD. The microstructure of the carboxymethylated starches, studied using SEM, revealed that the integrity of the starch granules was partially preserved at low aqueous ethanol levels when no kneading block was used. However, for all other reaction conditions either granule agglomeration or fusion was observed. XRD analysis indicated substantial loss of crystallinity in the carboxymethylated starches, irrespective of the damage to the granule structure. The highest DS and the highest reaction efficiency obtained were 1.54 and 0.42, respectively.
Synthesis of soluble N‐functionalized polysaccharide derivatives using phenyl carbonate precursor and their application as catalysts
Authors: Pourjavadi Ali , Seidi Farzad , Afjeh Soofieh S. , Nikoseresht Navid , Salimi Hamid , Nemati Navid
Published: September 2011

Soluble N‐functionalized basic and cationic polysaccharides have been synthesized using polysaccharide phenyl carbonate as a precursor. The products and intermediates were thoroughly characterized by conventional methods. The quaternization of amino intermediates in various conditions was studied. Moreover, the potential of basic polymers as green and selective catalysts in Knoevenagel reaction was investigated. In all cases, only one isomer was obtained.
What are the limits of accuracy in fetal weight estimation with conventional biometry in two‐dimensional ultrasound? A novel postpartum study
Authors: Kehl S. , Schmidt U. , Spaich S. , Schild R. L. , Sütterlin M. , Siemer J.
Published: September 2011

Objective

Commonly used formulae for fetal weight estimation, including combinations of several biometric parameters, lack accuracy despite efforts to improve them. This study aimed to investigate the limits of fetal weight estimation based on conventional biometric parameters on two‐dimensional (2D) ultrasound by developing and evaluating new weight equations using postpartum biometric parameters.

Methods

This was a prospective multicenter study including 628 singleton pregnancies at term. Inclusion criteria were healthy newborns with no physical or chromosomal malformations. Postpartum measurement of head circumference, abdominal circumference and thigh length was performed. Six ‘best‐fit’ formulae were derived using forward regression analysis in a formula‐finding group (n = 419), and their accuracy was compared with birth weight in an evaluation group (n = 209) using percentage error, absolute percentage error, limits of agreement and the proportion of weight estimations falling within a discrepancy level of ± 10%.

Results

The new formulae showed no systematic error, with SD for the percentage error between 7.42 and 8.77 and no significant differences between median absolute percentage errors (4.84–5.71). They included 74.6–81.3% of neonates within a discrepancy level of 10%. With regard to the 95% limits of agreement, weight estimates were within a range of about ± 500 g.

Conclusion

These results show that a good sonographic weight formula has the following features: no systematic error, an SD of about 7% and inclusion of 80% of cases within a discrepancy level of 10%. The study indicates that the current accuracy of fetal weight estimation with conventional biometric parameters by 2D ultrasound has reached its limits. Further improvement will probably only be achieved through new approaches in ultrasonography. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.
Multiuser two‐way relay processing and power control methods for cognitive radio networks
Authors: Jiang Dongmei , Zhang Haixia , Yuan Dongfeng
Published: September 2011

We consider a cognitive radio system where a secondary network shares the spectrum band with a primary network. Aiming at improving the frequency efficiency of the secondary network, we set a multiantenna relay station in the secondary network to perform two‐way relaying. Three linear processing schemes at the relay station based on zero forcing, zero forcing‐maximum ratio transmission, and minimum mean square error criteria are derived to guarantee the quality of service of primary users and to suppress the intrapair and interpair interference among secondary users (SUs). In addition, the transmit power of SUs is optimized to maximize the sum rate of SUs and to limit the interference brought to PUs. Numerical results show that the proposed multiuser two‐way relay processing schemes and the optimal power control policies can efficiently limit the interference caused by the secondary network to primary users, and the sum rate of SUs can also be greatly improved. Copyright © 2011 John Wiley & Sons, Ltd.
Unconditional, on the directions of arrival, statistics of the adaptive antenna arrays
Authors: Kaifas Theodoros N.
Published: September 2011

A comprehensive study on the statistics of adaptive antenna arrays is presented. The main contribution is the derivation of the probability distribution function of the cochannel interference for the uplink of mobile communications systems, unconditioned on the interferers' directions of arrival. Closed‐form results for the cumulative distribution function, moment generating function, and outage probability are also reported. Numerical verification is provided, utilizing both simulation and published data. Copyright © 2011 John Wiley & Sons, Ltd.