bluuebunny/crossref_metadata_2025 huggingface dataset:
Mucopolysaccharidosis I: Management and Treatment Guidelines
Authors: Muenzer Joseph , Wraith James E. , Clarke Lorne A. ,   and the International Consensus Panel on the Management and Treatment of Mucopolysaccharidosis I
Published: December 2008

OBJECTIVE. Disease management for mucopolysaccharidosis type I has been inconsistent because of disease rarity (∼1 case per 100000 live births), phenotypic heterogeneity, and limited therapeutic options. The availability of hematopoietic stem cell transplantation and the recent introduction of enzyme replacement therapy for mucopolysaccharidosis I necessitate the establishment of system-specific management guidelines for this condition.

METHODS. Twelve international experts on mucopolysaccharidosis I met in January 2003 to draft management and treatment guidelines for mucopolysaccharidosis I. Initial guidelines were revised and updated in 2008, on the basis of additional clinical data and therapeutic advances. Recommendations are based on our extensive clinical experience and a review of the literature.

RESULTS.All patients with mucopolysaccharidosis I should receive a comprehensive baseline evaluation, including neurologic, ophthalmologic, auditory, cardiac, respiratory, gastrointestinal, and musculoskeletal assessments, and should be monitored every 6 to 12 months with individualized specialty assessments, to monitor disease progression and effects of intervention. Patients are best treated by a multidisciplinary team. Treatments consist of palliative/supportive care, hematopoietic stem cell transplantation, and enzyme replacement therapy. The patient's age (>2 years or ≤2 years), predicted phenotype, and developmental quotient help define the risk/benefit profile for hematopoietic stem cell transplantation (higher risk but can preserve central nervous system function) versus enzyme replacement therapy (low risk but cannot cross the blood-brain barrier).

CONCLUSION. We anticipate that provision of a standard of care for the treatment of patients with mucopolysaccharidosis I will optimize clinical outcomes and patients' quality of life.
Photoisomers: Obfuscating Factors in Clinical Peroxidase Measurements of Unbound Bilirubin?
Authors: McDonagh Antony F. , Vreman Hendrik J. , Wong Ronald J. , Stevenson David K.
Published: December 2008

OBJECTIVES. The objectives of the study were to measure the effect of 4Z,15E-bilirubin on peroxidase free bilirubin measurements and to review the literature on this topic.

METHODS. 4Z,15E-Bilirubin was generated in situ in serum or serum albumin solution through controlled irradiation of isomerically pure 4Z,15Z-bilirubin IXα, under conditions in which the total amount of bilirubin remained constant. Reactions were monitored by difference spectroscopy, to ensure that solutions were not irradiated beyond the initial photostationary state and that concentrations of other isomers were kept to a minimum. Prepared in this way, 10% to 25% of the total bilirubin in the final solutions was in the form of the 4Z,15E-isomer. Free bilirubin in the solutions was measured with a peroxidase method, before and after irradiation. The use of bovine serum albumin as a surrogate for human albumin in in vitro studies also was investigated.

RESULTS. The findings of previous studies are not altogether consistent, with a common flaw in several being the failure to measure photoisomer concentrations. For bilirubin in serum albumin solution, conversion of ∼25% of the 4Z,15Z-isomer to 4Z,15E-bilirubin led to a much smaller decrease (<20%) in the apparent free bilirubin concentration; for bilirubin in serum, conversion of ∼15% of the 4Z,15Z-isomer to photoisomers resulted in a much larger increase (∼40%). Irradiation of bilirubin in bovine serum albumin solution generated a very different array of photoisomers than that observed in human albumin solutions.

CONCLUSIONS. The effect of photoisomers on the accuracy and specificity of free 4Z,15Z-bilirubin measurements remains uncertain. In a clinical setting, free bilirubin measurements need to be interpreted with caution when samples contain photoisomers. Irradiated bovine albumin solutions of isomerically impure bilirubin used in previous studies are poor models for investigating the effects of phototherapy in humans and the albumin binding of photoisomers.
Comparison of T-SPOT.TB Assay and Tuberculin Skin Test for the Evaluation of Young Children at High Risk for Tuberculosis in a Community Setting
Authors: Nicol Mark P. , Davies Mary-Ann , Wood Kathryn , Hatherill Mark , Workman Lesley , Hawkridge Anthony , Eley Brian , Wilkinson Katalin A. , Wilkinson Robert J. , Hanekom Willem A. , Beatty David , Hussey Gregory
Published: December 2008

OBJECTIVE. We wished to compare the sensitivity of an enzyme-linked immunospot assay (T-SPOT.TB; Oxford Immunotec, Oxford, United Kingdom) and the tuberculin skin test for the detection of tuberculosis infection in very young children being evaluated for active tuberculosis in a rural community setting.

METHODS. Children with a history of exposure to tuberculosis and children presenting to a local clinic or hospital with symptoms suggesting tuberculosis were admitted to a dedicated case verification ward. T-SPOT.TB testing was performed, and children were evaluated with a clinical examination, a tuberculin skin test, chest radiographs, and cultures of induced sputum and gastric lavage specimens. The diagnosis was determined by using a clinical algorithm.

RESULTS. A total of 243 children (median age: 18 months) were recruited, of whom 214 (88%) had interpretable T-SPOT.TB results. Children ≥12 months of age were more likely than younger children to have positive T-SPOT.TB results, whereas tuberculin skin test results were unaffected by age. The sensitivity of the T-SPOT.TB was no better than that of the tuberculin skin test for culture-confirmed tuberculosis (50% and 80%, respectively) and was poorer for the combined group of culture-confirmed and clinically probable tuberculosis (40% and 52%, respectively). For the 50 children clinically categorized as not having tuberculosis, the specificity of both the T-SPOT.TB and the tuberculin skin test was 84%.

CONCLUSIONS. For young children presenting in a community setting after exposure to tuberculosis or with symptoms suggesting tuberculosis, T-SPOT.TB cannot be used to exclude active disease. The sensitivity of this assay may be impaired for very young children.
Intrauterine, Early Neonatal, and Postdischarge Growth and Neurodevelopmental Outcome at 5.4 Years in Extremely Preterm Infants After Intensive Neonatal Nutritional Support
Authors: Franz Axel R. , Pohlandt Frank , Bode Harald , Mihatsch Walter A. , Sander Silvia , Kron Martina , Steinmacher Jochen
Published: December 2008

OBJECTIVE. Extremely preterm infants are at risk for poor growth and impaired neurodevelopment. The objective of this study was to determine whether intrauterine, early neonatal, or postdischarge growth is associated with neurocognitive and motor-developmental outcome in extremely preterm infants.

METHODS. Surviving children who were born between July 1996 and June 1999 at <30 weeks' gestation and with a birth weight <1500 g were evaluated at the age of school entry by application of (1) a standardized neurologic evaluation, (2) the Kaufmann Assessment Battery for Children, and (3) the Gross Motor Function Classification Scale. Growth was assessed on the basis of SD scores of weight and head circumference measured at birth, at discharge, and at the time of the follow-up examination. All infants had received intensive early nutritional support.

RESULTS. A total of 219 (83%) of 263 long-term survivors were evaluated at a median corrected age of 5.4 years. Increasing SD scores for weight and head circumference from birth to discharge were associated with a reduced risk for an abnormal neurologic examination. Catch-up growth of head circumference from birth to discharge was also associated with a reduced risk for impaired mobility. Weight SD score at birth, an increase of weight SD score from birth to discharge, and an increase of head circumference SD score from discharge to follow-up had an effect on the mental processing composite score. The effects of growth on neurodevelopment were by far exceeded by the consequences of intraventricular and periventricular hemorrhage.

CONCLUSIONS. Growth from birth to discharge seemed to be associated with long-term motor development. Cognitive development was associated with intrauterine growth measured as weight at birth, early neonatal weight gain, and postdischarge head circumference growth. Improving particularly early neonatal growth may improve long-term outcome in extremely preterm infants, but the effects of improved growth may only be small.
Trends in the Diagnosis of Overweight and Obesity in Children and Adolescents: 1999–2007
Authors: Benson Lacey , Baer Heather J. , Kaelber David C.
Published: December 2008

OBJECTIVE. Pediatric overweight and obesity are increasingly prevalent problems and have received much attention in recent years, but it is unclear whether this publicity has affected diagnosis by clinicians. We undertook the current study to assess trends in diagnosis rates of overweight and obesity in children.

PATIENTS AND METHODS. We analyzed electronic medical record data from 60711 patients aged 2 through 18 years with at least 1 well-child visit between June 1999 and October 2007 in a large academic medical system in northeast Ohio. Diagnosis of weight problems among children classified as overweight and obese was assessed by using International Classification of Diseases, Ninth Revision codes. Logistic regression was used to examine the impact of patient characteristics on diagnosis and to investigate trends over the study period.

RESULTS. On retrospective review of BMI measurements recorded for patients during the study period, 19% of the children were overweight, 23% were obese, and 8% (33% of the obese patients) were severely obese; among these, 10% of overweight patients, 54% of obese patients, and 76% of severely obese patients had their conditions diagnosed. BMI, age, and number of overweight visits were positively associated with diagnosis. Female patients were more likely to have been diagnosed than male patients. Black and Hispanic patients were more likely to have been diagnosed than white patients. There was a statistically significant trend toward increasing diagnosis during the study period, although the percentage of patients diagnosed per year seemed to plateau or decrease after 2005.

CONCLUSIONS. Although clear BMI definitions of pediatric weight problems exist, a large percentage of overweight and obese patients remain undiagnosed. Diagnosis increased during the study period but remained low among overweight children, for whom early intervention may be more effective. Identification of overweight and obese patients is the first step in addressing this growing epidemic.
The Problem With Dr Bob's Alternative Vaccine Schedule
Authors: Offit Paul A. , Moser Charlotte A.
Published: December 2008

In October 2007, Dr Robert Sears, in response to growing parental concerns about the safety of vaccines, published The Vaccine Book: Making the Right Decision for Your Child. Sears' book is enormously popular, having sold >40000 copies. At the back of the book, Sears includes “Dr Bob's Alternative Vaccine Schedule,” a formula by which parents can delay, withhold, separate, or space out vaccines. Pediatricians now confront many parents who insist that their children receive vaccines according to Sears' schedule, rather than that recommended by the American Academy of Pediatrics, the Centers for Disease Control and Prevention, and the American Academy of Family Physicians. This article examines the reasons for the popularity of Sears' book, deconstructs the logic and rationale behind its recommendations, and describes how Sears' misrepresentation of vaccine science misinforms parents trying to make the right decisions for their children.
Failure to Predict Hemolysis and Hyperbilirubinemia by IgG Subclass in Blood Group A or B Infants Born to Group O Mothers
Authors: Kaplan Michael , Na'amad Mira , Kenan Aner , Rudensky Bernard , Hammerman Cathy , Vreman Hendrik J. , Wong Ronald J. , Stevenson David K.
Published: December 2008

OBJECTIVE. Direct antibody titer–positive, blood group A or B neonates who are born to group O mothers may be at risk for hemolysis and hyperbilirubinemia. Immunoglobulin G1 and immunoglobulin G3 subclasses are associated with increased hemolysis relative to immunoglobulin G2 and immunoglobulin G4. We investigated whether identification of immunoglobulin G subclass 1 or 3 may be predictive of hemolysis and hyperbilirubinemia.

METHODS. Direct antibody titer-positive, blood group A and B neonates born to group O mothers were tested for the presence of immunoglobulin G subclasses 1 and 3 in umbilical cord blood by using a commercially available gel testing technology. By inference, neonates in whom neither immunoglobulin G1 nor immunoglobulin G3 were detected were designated immunoglobulin G2 and/or 4. Mandatory plasma total bilirubin was measured at discharge, and additional measurements performed as clinically indicated. Hyperbilirubinemia was defined as any plasma total bilirubin value >95th percentile for hour of life. Blood carboxyhemoglobin and total hemoglobin concentrations were also measured on the predischarge sample. Measured carboxyhemoglobin, expressed as percentage of total hemoglobin, was corrected for ambient carbon monoxide to derive “corrected carboxyhemoglobin,” a sensitive index of heme catabolism. The corrected carboxyhemoglobin/total hemoglobin ratio was calculated to correct for any differences in total hemoglobin mass between groups.

RESULTS. Eighty-two infants were studied, 18 of whom were designated as immunoglobulin G1, 0 as immunoglobulin G3, and 64 as immunoglobulin G2 and/or 4. The incidence of plasma total bilirubin >95th percentile was similar between the subgroupings. Corrected carboxyhemoglobin values and corrected carboxyhemoglobin/total hemoglobin ratio were also similar between the subgroupings.

CONCLUSIONS. Immunoglobulin G1 was found in 22% of direct antibody titer–positive, group A and B neonates who were born to group O mothers, whereas immunoglobulin G3 was rare. Hemolysis and hyperbilirubinemia could not be predicted by this gel technique that enabled identification of these immunoglobulin G subclasses.
High‐Impact Articles Related to the Management of Heart Failure: 2008 Update
Authors: Jackevicius Cynthia A. , Page Robert L. , Chow Sheryl , Dunn Steven P. , Lee Craig R. , Ng Tien M. H. , Rodgers Jo E. , Vardeny Orly , Wiggins Barbara S. , Munger Mark A.
Published: December 2008

This compilation is part of a series of articles identifying important literature in cardiovascular pharmacotherapy. This bibliography focuses on pharmacotherapeutic management of acute decompensated and chronic heart failure and provides an update of the heart failure bibliography published in Pharmacotherapy in 2004. Most of the cited works present the results of landmark clinical studies that have shaped the management of patients with heart failure. Limited primary literature is available for some topics, thus pertinent review articles are also listed. In addition, consensus documents formed by expert panels are reviewed. This compilation may serve as a teaching tool, reference resource, or update of the literature for pharmacy clinicians, physicians, and students.
Synthesis of 5-Substituted 3-Amino-1H-Pyrazole-4-Carbonitriles as Precursors for Microwave Assisted Regiospecific Syntheses of Pyrazolo[1,5-a]Pyrimidines
Authors: Al-Qalaf Fawzia , Mandani Faisal , Abdelkhalik Mervat Mohammed , Bassam Abeer Abdulrahman
Published: December 2008

A simple route to 3-oxoalkanonitrile 5, aprecursor of the title compounds is described. Reaction of enaminones 2 with hydroxylamine hydrochloride in ethanol yielded aldoximes 3 that were converted readily into 5 in basic medium. This method has been successfully applied with a number of substrates and resulted in excellent yields of the products. Reacting 5 with trichloroacetonitrile afforded 3-amino-2-aroyl-4,4,4-trichloro-2-butenenitriles 6 that condensed with hydrazines to yield 3-amino-1H-pyrazole-4-carbonitrilederivatives 8. Substituted pyrazolo[1,5-a]pyridmidines have been prepared with regioselective condensation reactions of 8 with nonsymmetrical dielectrophiles. The structures of compounds obtained were deduced based on 1H-NMR, 1H-15N HMBC- measurements.
La responsabilité, une technique de gouvernementalité néolibérale ?
Authors: Hache Émilie
Published: December 2008

Résumé La plupart des analyses portant sur l’art de gouverner néolibéral, à la suite de Foucault, se retrouvent autour de la responsabilisation de l’individu, comme (re)configuration privilégiée du transfert des responsabilités traditionnelles de l’État sur (certains) individus dans lequel s’engagent, entre autres, les politiques néolibérales. Nous nous intéresserons ici à l’examen – partiel, faute de place – des techniques de fabrication de cette « responsabilisation individuelle » ; et tenterons de contribuer à l’élaboration d’une parade, en nous attachant à la « faille » sur laquelle s’appuie ce sophisme pour que « ça marche » – au sens tout du moins où il est assez séduisant pour inhiber les ripostes. Le tour de passe-passe repose sur la confusion désarmante entre la valorisation de la responsabilité morale des individus – au sens d’une capacité à agir c’est-à-dire aussi à prendre ses responsabilités –, désirée et souhaitée par le plus grand nombre, et l’individualisation moralisante de la prise en charge matérielle de soi-même sous peine d’accusation d’irresponsabilité. L’enjeu de ce « décryptage » est de permettre de ne pas se priver de la ressource des processus d’ empowerment (« mise en capacité collective des individus) pour réinventer la gauche.
Modeling of coupled mass and heat transfer through venting membranes for automotive applications
Authors: Barkallah Amine , Mörée Johana , Sanchez Jose , Bocquet Stephanie Druon , Rivenc Jean
Published: December 2008

Experimental and theoretical approaches based on a mathematical model, have been developed to study the evolution of environmental parameters (temperature, total pressure, relative humidity, and water vapor partial pressure) inside a housing of an electronic device with a window containing a macroporous membrane. The model was based on the coupling of mass and heat transfer taking into account the effects of polarization of concentration in boundary layers. Membranes have been characterized by mercury porosimetry, liquid entry pressure measurements, scanning electron microscopy, and gas permeation. Once the model was experimentally validated, it was applied to investigate the influence of membranes on heat and mass transfer and to study the impact of the boundary layers on the global mass transport. The results demonstrated the importance of the membrane choice and dimensions to get the best temperature regulation and avoid water condensation inside an automotive electronic control unit (ECU). © 2008 American Institute of Chemical Engineers AIChE J, 2009
Long‐term growth following neonatal anatomic repair of transposition of the great arteries
Authors: Swan Jonathan W. , Whntraub Robert G. , Radley‐Smith Rosemary , Yacoub Magdi
Published: December 2008

Despite generally normal prenatal growth, surviving infants with transposition of the great arteries (TGA) frequently develop severe and progressive growth impairment which is not always fully reversed by elective atrial repair within the first year of life. This study was undertaken to determine the effect of neonatal anatomic repair of TGA on long‐term growth. Twenty‐three children with uncomplicated TGA were followed for a mean of 60 (12–90) months after anatomic repair at a mean age of 11 (1–40) days. Standardized measurements of weight, height, and head circumference for both patients and normal siblings were expressed as percentiles as well as in Z scores (in standard deviations from the mean for age and sex) based on internationally recognized standards. At latest follow‐up, 22 (96%) of the patients were above the 3rd percentile for weight and 21 (91%) for both height and head circumference, with 13 (57%), 11 (48%), and 13 (57%) above the 50th percentile for each respective parameter. The mean Z scores (± SD) for weight, height, and head circumference for the patient group were – 0.1 ± 1.2, – 0.2 ± 1.3, and – 0.1 ± 1.1, respectively, and did not differ significantly from those of the reference population (p > 0.05 for each comparison). Paired comparisons of mean Z scores for each growth parameter with those of 35 normal siblings demonstrated no significant difference for weight or height and a small but significant difference for head circumference. Age at surgical repair (within the first 6 weeks of life), duration of follow‐up and the development of moderate supravalvar pulmonary stenosis were not statistically related to long‐term growth. These results indicate that in patients without extracardiac abnormalities, neonatal anatomic repair of uncomplicated TGA results in normal long‐term growth.
Optimization of preform temperature distribution for the stretch‐blow molding of PET bottles: Infrared heating and blowing modeling
Authors: Bordival M. , Schmidt F.M. , Maoult Y. Le , Velay V.
Published: December 2008

This study presents an optimization strategy developed for the stretch‐blow molding process. The method is based on a coupling between the Nelder‐Mead optimization algorithm and finite element (FE) simulations of the forming process developed using ABAQUS®. FE simulations were validated using in situ tests and measurements performed on 18.5 g—50 cl polyethylene terephthalate bottles. To achieve that, the boundary conditions were carefully measured for both the infrared heating and the blowing stages. The temperature distribution of the perform was predicted using a 3D finite‐volume software, and then applied as an initial condition into FE simulations. In addition, a thermodynamic model was used to predict the air pressure applied inside the preform, taking into account the relationship between the internal air pressure and the enclosed volume of the preform, i.e., the fluid‐structure interaction. It was shown that the model adequately predicts both the blowing kinematics and the thickness distributions of the bottle. In the second step, this model was combined to an optimization loop to automatically compute the best preform temperature distribution, providing a uniform thickness for the bottle. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Impact of foreign ownership on innovation
Authors: Díaz‐Díaz Nieves Lidia , Aguiar‐Díaz Inmaculada , De Saá‐Pérez Petra
Published: December 2008

Abstract On the basis of longitudinal data for a sample of 1267 Spanish industrial firms over a period of 5 years, this paper analyses the impact of foreign ownership concentration on the firm's innovation performance. To that end, the study investigates how the level of ownership affects the firm's new product development. The results reflect no significant differences between the innovation of foreign‐owned firms and that of domestically owned firms. However, the results reveal that up to a certain level of foreign ownership, the lower possibility of appropriation of rents has a negative effect on innovation, while above that level of foreign ownership, the possibility of appropriating those rents increases the firm's innovation performance.
Organizational invariants and organizational change
Authors: Grandori Anna , Prencipe Andrea
Published: December 2008

Abstract Existing conceptualizations of organization form in organization theory have led to viewing organizational change in two opposite ways: either it is assumed that organization cannot significantly change – and therefore change is driven predominantly by selection‐based evolutionary processes – or it is assumed that organization can and should change altogether – as they shift from one form to another, due to complementarities among organizational elements and fit with context. This paper points out the limitations of these views (as well as of intermediate ‘incremental change’ views) based on the degree of change deemed to be possible and effective. The paper then outlines a more general model, overcoming those limitations, and conceptualizing change as a combination of organizational variants and invariants, intended as qualitatively different organizational elements. The increased predictive, explanatory, and prescriptive power of the proposed approach is illustrated using a longitudinal case study of organizational changes in Pilkington.
Structure and reactions of carbon and hydrogen on Ru(0001): A scanning tunneling microscopy study
Authors: Shimizu Tomoko K. , Mugarza Aitor , Cerdá Jorge I. , Salmeron Miquel
Published: December 2008

The interaction between carbon and hydrogen atoms on a Ru(0001) surface was studied using scanning tunneling microscopy (STM), density functional theory (DFT) and STM image calculations. Formation of CH species by reaction between adsorbed H and C was observed to occur readily at 100 K. When the coverage of H increased new complexes of the form of CH+nH (n=1, 2, and 3) were observed. These complexes, never observed before, might be precursors for further hydrogenation reactions. DFT analysis reveals that a considerable energy barrier exists for the CH+H→CH2 reaction.
Proton assisted recoupling and protein structure determination
Authors: De Paëpe Gaël , Lewandowski Józef R. , Loquet Antoine , Böckmann Anja , Griffin Robert G.
Published: December 2008

We introduce a homonuclear version of third spin assisted recoupling, a second-order mechanism that can be used for polarization transfer between C13 or N15 spins in magic angle spinning (MAS) NMR experiments, particularly at high spinning frequencies employed in contemporary high field MAS experiments. The resulting sequence, which we refer to as proton assisted recoupling (PAR), relies on a cross-term between H1–C13 (or H1–N15) couplings to mediate zero quantum C13–C13 (or N15–N15 recoupling). In particular, using average Hamiltonian theory we derive an effective Hamiltonian for PAR and show that the transfer is mediated by trilinear terms of the form C1±C2∓HZ for C13–C13 recoupling experiments (or N1±N2∓HZ for N15–N15). We use analytical and numerical simulations to explain the structure of the PAR optimization maps and to delineate the PAR matching conditions. We also detail the PAR polarization transfer dependence with respect to the local molecular geometry and explain the observed reduction in dipolar truncation. Finally, we demonstrate the utility of PAR in structural studies of proteins with C13–C13 spectra of uniformly C13, N15 labeled microcrystalline Crh, a 85 amino acid model protein that forms a domain swapped dimer (MW=2×10.4 kDa). The spectra, which were acquired at high MAS frequencies (ωr2π>20 kHz) and magnetic fields (750–900 MHz H1 frequencies) using moderate rf fields, exhibit numerous cross peaks corresponding to long (up to 6–7 Å) C13–C13 distances which are particularly useful in protein structure determination. Using results from PAR spectra we calculate the structure of the Crh protein.
Probing dynamics of single molecules: Nonlinear spectroscopy approach
Authors: Shikerman F. , Barkai E.
Published: December 2008

A two level model of a single molecule undergoing spectral diffusion dynamics and interacting with a sequence of two short laser pulses is investigated. Analytical solution for the probability of n=0,1,2 photon emission events for the telegraph and Gaussian processes is obtained. We examine under what circumstances the photon statistics emerging from such pump-probe setup provides new information on the stochastic process parameters and what are the measurement limitations of this technique. The impulsive and selective limits, the semiclassical approximation, and the fast modulation limit exhibit general behaviors of this new type of spectroscopy. We show that in the fast modulation limit, where one has to use impulsive pulses in order to obtain meaningful results, the information on the photon statistics is contained in the molecule’s dipole correlation function, equivalently to continuous wave experiments. In contrast, the photon statistics obtained within the selective limit depends on the both spectral shifts and rates and exhibits oscillations, which are not found in the corresponding line shape.
Ab initio calculation of interatomic decay rates of excited doubly ionized states in clusters
Authors: Kolorenč Přemysl , Averbukh Vitali , Gokhberg Kirill , Cederbaum Lorenz S.
Published: December 2008

Recently, a computational technique for ab initio calculation of the interatomic and intermolecular nonradiative decay processes has been developed [V. Averbukh and L. S. Cederbaum, J. Chem. Phys. 123, 204107 (2005)]. It combines the Fano formalism with the Green’s function method known as the algebraic diagrammatic construction. The problem of normalization of continuum wave functions stemming from the use of the Gaussian basis sets is solved by using the Stieltjes imaging technique. In the present paper, the methodology is extended in order to describe the interatomic decay of excited doubly ionized states of clusters. The new computational scheme is applied to compute the interatomic decay rates of doubly ionized states formed by Auger relaxation of core vacancies in NeAr and MgNe van der Waals clusters.
Quantum size effects in Bi films grown on GaAs (110)
Authors: Abu-Samak Mahmoud
Published: December 2008

Photoemission results, obtained with a helium-discharge lamp on the Bi/GaAs(110) interface shows strong modifications in the electronic structure of the low temperature deposited Bi overlayer upon annealing to room temperature, accompanied by developing of a sharp low energy electron-diffraction pattern. This behavior is consistent with the hypothesis of quantum size effects influence on growth morphology.
Freezing of charged colloids in slit pores
Authors: Grandner Stefan , Klapp Sabine H. L.
Published: December 2008

Using Monte Carlo simulations in the grand canonical and isobaric ensembles we investigate freezing phenomena in a charged colloidal suspension confined to narrow slit pores. Our model involves only the macroions which interact via a Derjaguin–Landau–Verwey–Overbeek (DLVO) potential supplemented by a soft-sphere potential. We focus on DLVO parameters typical for moderately charged silica particles (with charges Z∼35) in solvents of low ionic strengths. The corresponding DLVO interactions are too weak to drive a (bulk) freezing transition. Nevertheless, for sufficiently small surface separations Lz the confined systems display not only layering but also significant in-plane crystalline order at chemical potentials where the bulk system is a globally stable fluid (capillary freezing). At confinement conditions related to two-layer systems the observed in-plane structures are consistent with those detected in ground state calculations for perfect Yukawa bilayers [R. Messina and H. Löwen, Phys. Rev. Lett. 91, 146101 (2003)]. Here we additionally observe (at fixed Lz) a compression-induced first-order phase transition from a two-layer to a three-layer system with different in-plane structure, in agreement with previous findings for pure hard spheres.
A short working distance multiple crystal x-ray spectrometer
Authors: Dickinson B. , Seidler G. T. , Webb Z. W. , Bradley J. A. , Nagle K. P. , Heald S. M. , Gordon R. A. , Chou I. M.
Published: December 2008

For x-ray spot sizes of a few tens of microns or smaller, a millimeter-sized flat analyzer crystal placed ∼1 cm from the sample will exhibit high energy resolution while subtending a collection solid angle comparable to that of a typical spherically bent crystal analyzer (SBCA) at much larger working distances. Based on this observation and a nonfocusing geometry for the analyzer optic, we have constructed and tested a short working distance (SWD) multicrystal x-ray spectrometer. This prototype instrument has a maximum effective collection solid angle of 0.14 sr, comparable to that of 17 SBCA at 1 m working distance. We find good agreement with prior work for measurements of the Mn Kβ x-ray emission and resonant inelastic x-ray scattering for MnO, and also for measurements of the x-ray absorption near-edge structure for Dy metal using Lα2 partial-fluorescence yield detection. We discuss future applications at third- and fourth-generation light sources. For concentrated samples, the extremely large collection angle of SWD spectrometers will permit collection of high-resolution x-ray emission spectra with a single pulse of the Linac Coherent Light Source. The range of applications of SWD spectrometers and traditional multi-SBCA instruments has some overlap, but also is significantly complementary.
Nonlinearly driven oscillations in the gyrotron traveling-wave amplifier
Authors: Chiu C. C. , Pao K. F. , Yan Y. C. , Chu K. R. , Barnett L. R. , Luhmann N. C.
Published: December 2008

By delivering unprecedented power and gain, the gyrotron traveling-wave amplifier (gyro-TWT) offers great promise for advanced millimeter wave radars. However, the underlying physics of this complex nonlinear system is yet to be fully elucidated. Here, we report a new phenomenon in the form of nonlinearly driven oscillations. A zero-drive stable gyro-TWT is shown to be susceptible to a considerably reduced dynamic range at the band edge, followed by a sudden transition into driven oscillations and then a hysteresis effect. An analysis of this unexpected behavior and its physical interpretation are presented.
Blueshift in MgxZn1−xO alloys: Nature of bandgap bowing
Authors: Ashrafi Almamun , Segawa Yusaburo
Published: December 2008

A Mg composition-dependent blueshift has been studied in MgxZn1−xO alloys deposited on 6H-SiC(0001) substrates. The localized exciton energy in MgxZn1−xO alloys for x∼0.3 was blueshifted in the range 212–248 meV. The large negative bowing parameter was estimated in MgxZn1−xO alloys to be 4.72±0.84 eV. This large bandgap bowing emphasizes the Stokes shift, which has been attributed to the existence of spontaneous polarization effects due to the polar growth of MgxZn1−xO/SiC heterostructure and local compositional inhomogeneity.
Phase-type quantum-dot-array diffraction grating
Authors: Wang Chuanke , Kuang Longyu , Wang Zhebin , Cao Leifeng , Liu Shenye , Ding Yongkun , Wang Deqiang , Xie Changqing , Ye Tianchun , Hu Guangyue
Published: December 2008

A novel phase-type quantum-dot-array diffraction grating (QDADG) is reported. In contrast to an earlier amplitude-type QDADG [C. Wang et al., Rev. Sci. Instrum. 78, 053503 (2007)], the new phase-type QDADG would remove the zeroth order diffraction at some certain wavelength, as well as suppressing the higher-order diffractions. In this paper, the basic concept, the fabrication, the calibration techniques, and the calibration results are presented. Such a grating can be applied in the research fields of beam splitting, laser probe diagnostics, and so on.
Three-valued magnetic tunnel junction for nonvolatile ternary content addressable memory application
Authors: Uemura Tetsuya , Yamamoto Masafumi
Published: December 2008

Three-valued epitaxial Co50Fe50/MgO/Co50Fe50 magnetic tunnel junctions (MTJs) were developed for nonvolatile ternary content addressable memory (TCAM) application. Four remanent magnetization states in the single-crystalline Co50Fe50 electrode, due to cubic anisotropy with easy axes of the ⟨110⟩ directions, result in four possible angular-dependent tunnel magnetoresistance ratios. Three states selected from among the four states were separated by more than 56% at room temperature. Analysis of the asteroid curve for Co50Fe50 indicated that a magnetic field along 22.5° from the ⟨110⟩ directions made it possible to change the magnetization direction of the selected cell without disturbing those of the half-selected cells in the MTJ arrays. A nonvolatile TCAM cell using the three-valued MTJ for three-level data storage was proposed, and its operation was verified by circuit simulation. The TCAM cell reduces the device count to 5, a value 1/3 that of conventional complementary metal-oxide semiconductor-based TCAMs.
Proteolytic fragments of laminin promote excitotoxic neurodegeneration by up-regulation of the KA1 subunit of the kainate receptor
Authors: Chen Zu-Lin , Yu Huaxu , Yu Wei-Ming , Pawlak Robert , Strickland Sidney
Published: December 2008

Degradation of the extracellular matrix (ECM) protein laminin contributes to excitotoxic cell death in the hippocampus, but the mechanism of this effect is unknown. To study this process, we disrupted laminin γ1 (lamγ1) expression in the hippocampus. Lamγ1 knockout (KO) and control mice had similar basal expression of kainate (KA) receptors, but the lamγ1 KO mice were resistant to KA-induced neuronal death. After KA injection, KA1 subunit levels increased in control mice but were unchanged in lamγ1 KO mice. KA1 levels in tissue plasminogen activator (tPA)–KO mice were also unchanged after KA, indicating that both tPA and laminin were necessary for KA1 up-regulation after KA injection. Infusion of plasmin-digested laminin-1 into the hippocampus of lamγ1 or tPA KO mice restored KA1 up-regulation and KA-induced neuronal degeneration. Interfering with KA1 function with a specific anti-KA1 antibody protected against KA-induced neuronal death both in vitro and in vivo. These results demonstrate a novel pathway for neurodegeneration involving proteolysis of the ECM and KA1 KA receptor subunit up-regulation.
The translocator maintenance protein Tam41 is required for mitochondrial cardiolipin biosynthesis
Authors: Kutik Stephan , Rissler Michael , Guan Xue Li , Guiard Bernard , Shui Guanghou , Gebert Natalia , Heacock Philip N. , Rehling Peter , Dowhan William , Wenk Markus R. , Pfanner Nikolaus , Wiedemann Nils
Published: December 2008

The mitochondrial inner membrane contains different translocator systems for the import of presequence-carrying proteins and carrier proteins. The translocator assembly and maintenance protein 41 (Tam41/mitochondrial matrix protein 37) was identified as a new member of the mitochondrial protein translocator systems by its role in maintaining the integrity and activity of the presequence translocase of the inner membrane (TIM23 complex). Here we demonstrate that the assembly of proteins imported by the carrier translocase, TIM22 complex, is even more strongly affected by the lack of Tam41. Moreover, respiratory chain supercomplexes and the inner membrane potential are impaired by lack of Tam41. The phenotype of Tam41-deficient mitochondria thus resembles that of mitochondria lacking cardiolipin. Indeed, we found that Tam41 is required for the biosynthesis of the dimeric phospholipid cardiolipin. The pleiotropic effects of the translocator maintenance protein on preprotein import and respiratory chain can be attributed to its role in biosynthesis of mitochondrial cardiolipin.
The peroxisomal membrane protein import receptor Pex3p is directly transported to peroxisomes by a novel Pex19p- and Pex16p-dependent pathway
Authors: Matsuzaki Takashi , Fujiki Yukio
Published: December 2008

Two distinct pathways have recently been proposed for the import of peroxisomal membrane proteins (PMPs): a Pex19p- and Pex3p-dependent class I pathway and a Pex19p- and Pex3p-independent class II pathway. We show here that Pex19p plays an essential role as the chaperone for full-length Pex3p in the cytosol. Pex19p forms a soluble complex with newly synthesized Pex3p in the cytosol and directly translocates it to peroxisomes. Knockdown of Pex19p inhibits peroxisomal targeting of newly synthesized full-length Pex3p and results in failure of the peroxisomal localization of Pex3p. Moreover, we demonstrate that Pex16p functions as the Pex3p-docking site and serves as the peroxisomal membrane receptor that is specific to the Pex3p–Pex19p complexes. Based on these novel findings, we suggest a model for the import of PMPs that provides new insights into the molecular mechanisms underlying the biogenesis of peroxisomes and its regulation involving Pex3p, Pex19p, and Pex16p.
PARP-1 ensures regulation of replication fork progression by homologous recombination on damaged DNA
Authors: Sugimura Kazuto , Takebayashi Shin-ichiro , Taguchi Hiroshi , Takeda Shunichi , Okumura Katsuzumi
Published: December 2008

Poly-ADP ribose polymerase 1 (PARP-1) is activated by DNA damage and has been implicated in the repair of single-strand breaks (SSBs). Involvement of PARP-1 in other DNA damage responses remains controversial. In this study, we show that PARP-1 is required for replication fork slowing on damaged DNA. Fork progression in PARP-1−/− DT40 cells is not slowed down even in the presence of DNA damage induced by the topoisomerase I inhibitor camptothecin (CPT). Mammalian cells treated with a PARP inhibitor or PARP-1–specific small interfering RNAs show similar results. The expression of human PARP-1 restores fork slowing in PARP-1−/− DT40 cells. PARP-1 affects SSB repair, homologous recombination (HR), and nonhomologous end joining; therefore, we analyzed the effect of CPT on DT40 clones deficient in these pathways. We find that fork slowing is correlated with the proficiency of HR-mediated repair. Our data support the presence of a novel checkpoint pathway in which the initiation of HR but not DNA damage delays the fork progression.
The sympathetic tone mediates leptin's inhibition of insulin secretion by modulating osteocalcin bioactivity
Authors: Hinoi Eiichi , Gao Nan , Jung Dae Young , Yadav Vijay , Yoshizawa Tatsuya , Myers Martin G. , Chua Streamson C. , Kim Jason K. , Kaestner Klaus H. , Karsenty Gerard
Published: December 2008

The osteoblast-secreted molecule osteocalcin favors insulin secretion, but how this function is regulated in vivo by extracellular signals is for now unknown. In this study, we show that leptin, which instead inhibits insulin secretion, partly uses the sympathetic nervous system to fulfill this function. Remarkably, for our purpose, an osteoblast-specific ablation of sympathetic signaling results in a leptin-dependent hyperinsulinemia. In osteoblasts, sympathetic tone stimulates expression of Esp, a gene inhibiting the activity of osteocalcin, which is an insulin secretagogue. Accordingly, Esp inactivation doubles hyperinsulinemia and delays glucose intolerance in ob/ob mice, whereas Osteocalcin inactivation halves their hyperinsulinemia. By showing that leptin inhibits insulin secretion by decreasing osteocalcin bioactivity, this study illustrates the importance of the relationship existing between fat and skeleton for the regulation of glucose homeostasis.
Electric Fields and Inflammation: May the Force be with You
Authors: Brown Simon B. , Dransfield Ian
Published: December 2008

Integrins are a family of ubiquitous cell surface receptors comprising heterodimers of β and α chains that are required for cell adhesion and motility. Integrin-dependent adhesion and signaling is associated with major conformational changes in the ectodomain as it shifts from a low-affinity “bent” to a high-affinity “extended” structure. The ability of a cell to regulate dynamically the affinity or activation state of an integrin, and hence its binding to extracellular matrix or cell adhesion molecules, is assumed to be driven by intracellular signaling events transmitted by protein binding to the cytoplasmic tail. The binding of an integrin to its ligand can then transmit signals back into the cell to regulate the formation of a macromolecular focal adhesion complex that effectively anchors the cytoskeleton to the adhesion site. Many proteins have been reported to associate physically and functionally with integrins, leading to altered signaling events. A particularly intriguing molecular association exists between integrins and transmembrane proteins that gate the movement of charge, especially voltage-gated potassium channels, although the significance of this interaction is not understood. Although ample evidence indicates that the engagement of integrins can promote potassium efflux by both excitable and nonexcitable cells, we speculate the converse, that the activation state of integrins is dynamically regulated by changes in a transmembrane potential. In this way, direct-current electric fields generated at a site of tissue injury can promote the galvanotaxis or directed migration of cells involved in tissue repair and inflammation.
Collective Bargaining and The Performance of the Public Schools
Authors: Moe Terry M.
Published: December 2008

Students of American politics rarely study public sector unions and their impacts on government. The literature sees bureaucratic power as rooted in expertise, but largely ignores the fact that bureaucrats often join unions to promote their own interests, and that the power of their unions may affect government and its performance. This article focuses on the public schools, which are among the most numerous government agencies in the country, and investigates whether collective bargaining by teachers—the key bureaucrats—affects the schools' capacity to educate children. Using California data, analysis shows that, in large school districts, restrictive labor contracts have a very negative impact on academic achievement, particularly for minority students. The evidence suggests, then, that public sector unions do indeed have important consequences for American public education. Whether they are consequential in other areas of government remains to be seen, but it is an avenue well worth pursuing.
The Effects of Strategic and Economic Interdependence on International Conflict Across Levels of Analysis
Authors: Maoz Zeev
Published: December 2008

This study develops a Social Network Analytic approach to conceptualize and measure interdependence across levels of analysis. This framework contains several innovations. First, it integrates “sensitivity interdependence”—the effects of changes in one state on other states—with “vulnerability interdependence”—the opportunity costs of breaking a relationship. Second, it measures interdependence at different levels of analysis and across multiple relationships. Third, it integrates multiple dimensions of interdependence into a single measure. I derive hypotheses from the realist and liberal paradigms regarding the effects of strategic and economic interdependence on monadic, dyadic, and systemic conflict. These hypotheses are tested via data on alliances, military capability, and trade. The findings provide robust support to the expectations of the liberal paradigm regarding the effects of strategic and economic interdependence on conflict. On the other hand, the expectations of the realist paradigm are not supported. I discuss the theoretical and empirical implications of this approach.
The pain in primary osteoarthritis of the knee. Its causes and treatment by osteotomy
Authors: Helal B
Published: December 2008

Some results of a clinical investigation of patients with osteoarthritis of the knee are described. The different varieties of pain which occur in osteoarthritis are detailed. A sub-group of patients with primary osteoarthritis of the knee is described. In this group “venous” pain predominated; the venographic appearances are typical, and in a large proportion of cases the veins outside the bone are manifestly abnormal. It is suggested that venous congestion within the bone results from extra-osseus vein disturbances, and leads to congestive bone pain and to progressive joint degeneration. The mechanism by which osteotomy produces relief of pain is analysed and discussed. A simple procedure which reproduces some of the benefits of osteotomy is described.
Clinical patterns and complications of diabetes mellitus in India
Authors: Lal H B , Bahl A L , Mathur K P , Chugh R N , Bhalla A S
Published: December 2008

The records of 274 diabetics attending an outpatient clinic in New Delhi have been reviewed and the patients classified into four main types.

The relationship of the disease to nutritional, socio-economic and environmental factors has been discussed.

The incidence of complications in the various types is reported and the differences between them analysed.