bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of periodic electrodiagnostic measurements to monitor motor recovery after different peripheral nerve lesions in the rat
Authors: Korte Nele , Schenk Henning C. , Grothe Claudia , Tipold Andrea , Haastert‐Talini Kirsten
Published: January 2011

Introduction:

The advantage of minimally invasive electrodiagnostic methods for periodic evaluation of reinnervation at predefined time intervals does not seem to be widely recognized. In this study, using a rat model, we assessed the utility of periodic electrodiagnostic measurements for monitoring ongoing motor recovery after peripheral nerve injuries of differing severity.

Methods:

In a comparative study, either unilateral sciatic nerve crush injury (n = 10), end‐to‐end coaptation (n = 5), or 10‐mm nerve autotransplantation (n = 10) were performed. During the 6–16‐week period thereafter compound muscle action potentials (CMAPs) were recorded percutaneously every week in anesthetized animals. Motor nerve conduction velocity and percentage of axon loss were calculated and compared with footprint analyses (static sciatic index, SSI) and evaluations of sensory recovery.

Results:

Our results clearly demonstrate that, although SSI measurements reliably demonstrated progress of regeneration after nerve crush injury only, differences in electrodiagnostically determined values precisely remodeled differences in axonal regeneration, which was confirmed by histomorphometric analysis of axonal regeneration.

Conclusions:

Percutaneous electrodiagnostic measurements enable reliable estimation of axonal regeneration parameters such as myelination and nerve fiber density and display in close proximity the actual status of axonal regeneration. Muscle Nerve 44: 63–73, 2011
Acellular nerve allografts in peripheral nerve regeneration: A comparative study
Authors: Moore Amy M. , Macewan Matthew , Santosa Katherine B. , Chenard Kristofer E. , Ray Wilson Z. , Hunter Daniel A. , Mackinnon Susan E. , Johnson Philip J.
Published: January 2011

Introduction: Processed nerve allografts offer a promising alternative to nerve autografts in the surgical management of peripheral nerve injuries where short deficits exist. Methods: Three established models of acellular nerve allograft (cold‐preserved, detergent‐processed, and AxoGen‐processed nerve allografts) were compared with nerve isografts and silicone nerve guidance conduits in a 14‐mm rat sciatic nerve defect. Results: All acellular nerve grafts were superior to silicone nerve conduits in support of nerve regeneration. Detergent‐processed allografts were similar to isografts at 6 weeks postoperatively, whereas AxoGen‐processed and cold‐preserved allografts supported significantly fewer regenerating nerve fibers. Measurement of muscle force confirmed that detergent‐processed allografts promoted isograft‐equivalent levels of motor recovery 16 weeks postoperatively. All acellular allografts promoted greater amounts of motor recovery compared with silicone conduits. Conclusion: These findings provide evidence that differential processing for removal of cellular constituents in preparing acellular nerve allografts affects recovery in vivo. Muscle Nerve, 2011
Scratch hardness–strength solutions for cohesive‐frictional materials
Authors: Bard Romain , Ulm Franz‐Josef
Published: January 2011

In this paper we develop analytical solutions for scratch hardness–strength relations for cohesive‐frictional materials of the Mohr–Coulomb and Drucker–Prager type. Based on the lower bound yield design approach, closed‐form solutions are derived for frictionless scratch devices, and validated against computational upper bound and elastoplastic finite element solutions. The influence of friction at the blade–material interface is also investigated, for which a simple computational optimization is proposed. Illustrated for scratch tests on cement paste, we show that the proposed solutions provide a convenient way to determine estimates of cohesion and friction parameters from scratch data, and may serve as a benchmark to identify the relevance of strength models for scratch test analysis. Copyright © 2011 John Wiley & Sons, Ltd.
Three‐dimensional finite element modeling of tire/ground interaction
Authors: Xia Kaiming , Yang Yunming
Published: January 2011

Tire/ground interaction has been an important issue in terramechanics, transportation and pavement engineering. Characterization of tire/ground interaction has been majorly investigated based on empirical approaches and field tests. So far very few dynamic tire/ground interaction models have been presented. This paper presents a three‐dimensional finite element model for tire/ground interaction. The rubber material is modeled as nearly incompressible finite strain hyperelasticity instead of being modeled as a rigid wheel. The tire is also modeled as bias type and steel rebars are embedded within the tire structure. The tire model is combined with the ground model to form a tire/ground interaction model. Both single tire/ground interaction and four‐tire vehicle/pavement interaction models are presented, which allow us to investigate a lot of issues easily and accurately, such as compaction, pavement response and pavement damage. Numerous simulations are carried out to demonstrate that the dynamic tire/terrain interaction model can be used to predict the dynamic ground response due to moving vehicle. Different tire rolling conditions can be easily incorporated into the tire/ground interaction model, which further substantiates the broad application of the model in transportation and pavement engineering. Copyright © 2011 John Wiley & Sons, Ltd.
Elevation of serum c‐reactive protein in patients with OAB and IC/BPS implies chronic inflammation in the urinary bladder
Authors: Chung Shiu‐Dong , Liu Hsin‐Tzu , Lin Heng , Kuo Hann‐Chorng
Published: January 2011

Aims

Chronic inflammation has been implicated in the development of overactive bladder (OAB) and interstitial cystitis/bladder pain syndrome (IC/BPS). An elevation of C‐reactive protein (CRP) has been associated with chronic inflammation and lower urinary tract symptoms. This study aims to elucidate the association between CRP and OAB or IC/BPS.

Methods

Serum CRP and urinary nerve growth factor (NGF) levels were examined in 70 patients with OAB (n = 22) or IC/BPS (n = 48) and compared with 33 normal controls. Data of serum CRP and urinary NGF levels were compared among the controls, IC/PBS, and OAB. The Spearmen correlation analysis test and ANOVA (Kruskal–Wallis) test were used for statistical analysis with P < 0.05 considered significant.

Results

Serum CRP levels were significantly higher in subjects with OAB (1.83 ± 2.30 mg/L vs. 0.59 ± 0.40 mg/L, P = 0.012) or IC/BPS (1.76 ± 3.56 mg/L vs. 0.59 ± 0.40 mg/L, P = 0.049) than in controls. No significant difference in CRP level was noted between patients with OAB and IC/BPS (P = 0.43). In a subgroup analysis, patients of OAB wet had higher serum CRP level than that of OAB dry (2.95 ± 3.08 mg/L vs. 0.90 ± 0.52 mg/L); however, the difference did not reach statistical significance (P = 0.34). The CRP between OAB wet and OAB patients with medical disease was not significantly different. There was no significant correlation between serum CRP and urinary NGF levels in the controls or patients with OAB or IC/BPS, except in the OAB patients with a CRP level >3 mg/L.

Conclusions

Our data support the association between chronic inflammation of the urinary bladder in patients with OAB or IC/BPS. Neurourol. Urodynam. 30:417–420, 2011. © 2011 Wiley‐Liss, Inc.
An adaptive concurrent multiscale method for the dynamic simulation of dislocations
Authors: Gracie Robert , Belytschko Ted
Published: February 2011

A continuum‐atomistic adaptive multiscale method is developed for the simulation of the dynamics of dislocations. Two key features of the method are (i) methods for both refining and coarsening the model, where coarsening refers to a continuum to atomistic transition and refinement to the opposite and (ii) error criteria for refining and coarsening. In coarsening of edge dislocation solutions, it is crucial to capture the discontinuities across the glide plane, which is accomplished here by the extended finite element method. Error criteria are developed in terms of energies so that the atomistic model tends to follow the core, where continuum models are generally quite inaccurate. The method is applied to two‐dimensional problems involving dislocations emitted from a void and from a crack tip. The results show good agreement with other multiscale methods and result in a large savings in computational effort. Copyright © 2011 John Wiley & Sons, Ltd.
A quasicontinuum methodology for multiscale analyses of discrete microstructural models
Authors: Beex L. A. A. , Peerlings R. H. J. , Geers M. G. D.
Published: February 2011

Many studies in different research fields use lattice models to investigate the mechanical behavior of materials. Full lattice calculations are often performed to determine the influence of localized microscale phenomena on large‐scale responses but they are usually computationally expensive. In this study the quasicontinuum (QC) method (Phil. Mag. A 1996; 73:1529–1563) is extended towards lattice models that employ discrete elements, such as trusses and beams. The QC method is a multiscale approach that uses a triangulation to interpolate the lattice model in regions with small fluctuations in the deformation field, while in regions of high interest the exact lattice model is obtained by refining the triangulation to the internal spacing of the lattice. Interpolation ensures that the number of unknowns is reduced while summation ensures that only a selective part of the underlying lattice model must be visited to construct the governing equations. As the QC method has so far only been applied to atomic lattice models, the existing summation procedures have been revisited for structural lattice models containing discrete elements. This has led to a new QC method that makes use of the characteristic structure of the considered truss network. The proposed QC method is, to the best of the authors' knowledge, the only QC method that does not need any correction at the interface between the interpolated and the fully resolved region and at the same time gives exact results unlike the cluster QC methods. In its present formulation, the proposed QC method can only be used for lattice models containing nearest neighbor interactions, but with some minor adaptations it can also be used for lattices with next‐nearest neighbor interactions such as atomic lattices. Copyright © 2011 John Wiley & Sons, Ltd.
Tetrahedral mesh generation using Delaunay refinement with non‐standard quality measures
Authors: Gosselin S. , Ollivier‐Gooch C.
Published: February 2011

This paper studies the practical performance of Delaunay refinement tetrahedral mesh generation algorithms. By using non‐standard quality measures to drive refinement, we show that sliver tetrahedra can be eliminated from constrained Delaunay tetrahedralizations solely by refinement. Despite the fact that quality guarantees cannot be proven, the algorithm can consistently generate meshes with dihedral angles between 18circ and 154∘. Using a fairer quality measure targeting every type of bad tetrahedron, dihedral angles between 14∘ and 154∘ can be obtained. The number of vertices inserted to achieve quality meshes is comparable to that needed when driving refinement with the standard circumradius‐to‐shortest‐edge ratio. We also study the use of mesh improvement techniques on Delaunay refined meshes and observe that the minimum dihedral angle can generally be pushed above 20∘, regardless of the quality measure used to drive refinement. The algorithm presented in this paper can accept geometric domains whose boundaries are piecewise smooth. Copyright © 2011 John Wiley & Sons, Ltd.
The influence of adult behaviors on child coping during venipuncture: A sequential analysis
Authors: Taylor Christine , Sellick Ken , Greenwood Ken
Published: January 2011

The aim of this exploratory study was to investigate the influences of adult behaviors on child coping behaviors during venipunctures (VPs) in an emergency department. Observations of children and adults from 66 VPs were coded using a modified version of the Child–Adult Medical Procedure Interaction Scale and analyzed using sequential analysis. Results showed adult reassurance behavior promoted child distress behaviors, such as crying, as well as nondistress behaviors, such as information seeking; adult distraction behaviors promoted children's distraction, control, and coping behaviors; and children frequently ignored adult behaviors. Findings suggest further exploration of children's internal strategies for coping, such as appraisal, and clarifying the role of adult reassurance in child coping behaviors. © 2011 Wiley Periodicals, Inc. Res Nurs Health
Experimental results of a control time delay system using optimal control
Authors: Santos Omar , Rodríguez‐Guerrero Liliam , López‐Ortega Omar
Published: January 2011

The optimal control for a temperature system with time delay is considered. Experimental results of the control system are presented in this contribution. The integral term in the controller is approximated by a quadrature method. Experimental results obtained demonstrate the effectiveness of the approximation method. By a simple analysis in time domain, we demonstrate the robustness of the optimal controller. We compare the optimal control's performance with an industrial PID controller. This controller was robustly tuned. The experiments indicate the correct optimization of the plant when the optimal control was employed, despite limitations in the sensor, actuators, non‐modeled dynamics, and uncertain parameters of the process. Copyright © 2011 John Wiley & Sons, Ltd.
Optimal control of radiative heat transfer in glass cooling with restrictions on the temperature gradient
Authors: Clever D. , Lang J.
Published: January 2011

This paper is motivated by an optimal boundary control problem for the cooling process of molten and already formed glass down to room temperature. The high temperatures at which glass is processed demand to include radiative heat transfer in the computational model. Since the complete radiative heat transfer equations are too complex for optimization purposes, we use simplified approximations of spherical harmonics coupled with a practically relevant frequency bands model. The optimal control problem is considered as a partial differential algebraic equation (PDAE)‐constrained optimization problem with box constraints on the control. In this paper, we augment the objective by a functional depending on the state gradient, which forces a minimization of thermal stress inside the glass. To guarantee consistent and grid‐independent values of the reduced objective gradient at the end of the cooling process, we pursue two approaches. The first includes the temperature gradient with a time‐dependent linearly decreasing weight. In the second approach, we augment the objective functional by the final state tracking and final state gradient optimization. To determine an optimal boundary control, we apply a projected gradient method with the Armijo step size rule. The reduced objective gradient is computed by the continuous adjoint approach. The arising time‐dependent PDAEs are numerically solved by variable step size one‐step methods of Rosenbrock type in time and adaptive multilevel finite elements in space. We present two‐dimensional numerical results for an infinitely long glass block and compare the two different approaches derived to ensure consistency at the end of the cooling process. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of starch gelatinization and oxidation on the rheological behavior of chitosan/starch blends
Authors: Horn Marilia M , Martins Virginia CA , Plepis Ana MG
Published: February 2011

Chitosan/starch blends represent an interesting alternative for the preparation of biocompatible drug delivery systems, packing materials and edible films. This paper reports on the effects of starch gelatinization and oxidation on the rheological behavior of chitosan/starch blends. The results show that the modifications in the starch structure cause changes in G′ (storage modulus) and G″ (loss modulus) as a function of frequency. For chitosan/starch, G″ is higher than G′, showing a viscous behavior. However, for chitosan/gelatinized starch and chitosan/oxidized starch, an increase in the angular frequency promotes a modulus crossover at ω = 0.02 and 0.04 rad s−1, respectively. The viscosity curves as a function of shear rate show that both modifications cause an increase in viscosity, and all blends show a non‐Newtonian behavior. Copyright © 2011 Society of Chemical Industry
Two‐dimensional gel proteome reference map of INS‐1E cells
Authors: D'Hertog Wannes , Maris Michael , Thorrez Lieven , Waelkens Etienne , Overbergh Lut , Mathieu Chantal
Published: February 2011

The insulin‐producing INS‐1E rat cell line is widely used as a model for studying β‐cells. It is a well‐characterized cell line, mainly used in diabetes research. We established a 2‐DE reference map for INS‐1E cells. Using MALDI‐TOF/TOF‐MS/MS, we identified 546 spots. These included various proteins with an important role in β‐cell physiology and with known roles as crucial proteins for diabetes development. We believe that the availability of this reference map will enhance our knowledge of β‐cell physiology.
An approach for identification of phosphoproteins using the G‐electrode‐loading method in two‐dimensional gel electrophoresis
Authors: Koga Kaori , Minohata Toshikazu
Published: February 2011

We assessed whether the G‐electrode‐loading method (GELM) was helpful in the protein analysis. GELM in 2‐DE was compared with the slip‐loading, the in‐gel rehydration and the cup‐loading in 2‐DE. GELM showed the best results for protein separation. A total of 14 spots that showed an increase with GELM were analyzed by MALDI‐TOF MS. In GELM, all of these spots were identified with a high score and a high sequence coverage. A membrane‐associated protein was identified and determined to have phosphorylated site. These tests show that GELM has several advantages for protein analysis compared with the traditional methods.
Mapping phosphoproteins in Neisseria meningitidis serogroup A
Authors: Bernardini Giulia , Laschi Marcella , Serchi Tommaso , Arena Simona , D'Ambrosio Chiara , Braconi Daniela , Scaloni Andrea , Santucci Annalisa
Published: February 2011

To investigate the phosphorylation capability of serogroup A Neisseria meningitidis (MenA) and to implement our knowledge in meningococcal biology and in bacterial post‐translational modifications, cell extracts were separated by 2‐DE and 51 novel phosphoproteins were revealed by the use of the highly specific Ser/Thr/Tyr‐phosphorylated proteins staining by Pro‐Q Diamond and identified by MALDI‐ToF/MS. Our results indicate that phosphorylation in MenA is comparable to that of other bacterial species. A first functional characterization of the identified modified proteins was also given, in order to understand their role in meningococcal physiopathology.
Quantitative proteomics (2‐D DIGE) reveals molecular strategies employed by Burkholderia cenocepacia to adapt to the airways of cystic fibrosis patients under antimicrobial therapy
Authors: Madeira Andreia , Santos Pedro M. , Coutinho Carla P. , Pinto‐de‐Oliveira Ana , Sá‐Correia Isabel
Published: February 2011

Chronic respiratory infections caused by Burkholderia cenocepacia in patients with cystic fibrosis (CF) are characterized by low responsiveness to antibiotic therapy and, in general, to a more rapid decline of lung function. To get clues into the molecular mechanisms underlying the adaptive strategies employed to deal with the stressing conditions of the CF lung including antibiotic therapy, quantitative proteomics (2‐D DIGE) was used to compare the expression programs of two clonal isolates retrieved from a chronically infected CF patient. Isolate IST439 was the first bacterium recovered while the clonal variant IST4113 was obtained after 3 years of persistent infection and intravenous therapy with ceftazidime/gentamicin. This isolate exhibits higher resistance levels towards different classes of antimicrobials. Proteins of the functional categories Energy metabolism, Translation, Nucleotide synthesis, Protein folding and stabilization are more abundant in IST4113, compared with IST439, suggesting an increased protein synthesis, DNA repair and stress resistance in IST4113. The level of proteins involved in peptidoglycan, membrane lipids and lipopolysaccharide synthesis is also altered and proteins involved in iron binding and transport are more abundant in IST4113. The quantitative comparison of the two proteomes suggests a genetic adaptation leading to increased antimicrobial resistance and bacterial persistence in the CF airways.
Abacus: A computational tool for extracting and pre‐processing spectral count data for label‐free quantitative proteomic analysis
Authors: Fermin Damian , Basrur Venkatesha , Yocum Anastasia K. , Nesvizhskii Alexey I.
Published: February 2011

We describe Abacus, a computational tool for extracting spectral counts from MS/MS data sets. The program aggregates data from multiple experiments, adjusts spectral counts to accurately account for peptides shared across multiple proteins, and performs common normalization steps. It can also output the spectral count data at the gene level, thus simplifying the integration and comparison between gene and protein expression data. Abacus is compatible with the widely used Trans‐Proteomic Pipeline suite of tools and comes with a graphical user interface making it easy to interact with the program. The main aim of Abacus is to streamline the analysis of spectral count data by providing an automated, easy to use solution for extracting this information from proteomic data sets for subsequent, more sophisticated statistical analysis.
Proteome changes in rat plasma in response to sibutramine
Authors: Choi Jung‐Won , Joo Jeong In , Kim Dong Hyun , Wang Xia , Oh Tae Seok , Choi Duk Kwon , Yun Jong Won
Published: February 2011

Sibutramine is an anti‐obesity agent that induces weight loss by selective inhibition of neuronal reuptake of serotonin and norepinephrine; however, it is associated with the risk of cardiovascular diseases (CVD), including heart attack and stroke. Here, we analyzed global protein expression patterns in plasma of control and sibutramine‐treated rats using proteomic analysis for a better understanding of the two conflicting functions of this drug, appetite regulation, and cardiovascular risk. The control (n=6) and sibutramine‐treated groups (n=6) were injected by vehicle and sibutramine, respectively, and 2‐DE combined with MALDI‐TOF/MS were performed. Compared to control rats, sibutramine‐administered rats gained approximately 18% less body weight and consumed about 13% less food. Plasma leptin and insulin levels also showed a significant decrease in sibutramine‐treated rats. As a result of proteomic analysis, 23 differentially regulated proteins were discovered and were reconfirmed by immunoblot analysis. Changed proteins were classified into appetite regulation and cardiovascular risk, according to their regulation pattern. Because the differential levels of proteins that have been well recognized as predictors of CVD risk were not well matched with the results of our proteomic analysis, this study does not conclusively prove that sibutramine has an effect on CVD risk.
Cyclic voltammetric studies of 1,2,4‐trihydroxy‐9,10‐anthraquinone, its interaction with calf thymus DNA and anti‐leukemic activity on MOLT‐4 cell lines: a comparison with anthracycline anticancer drugs
Authors: Das Piyal , Guin Partha Sarathi , Mandal Parikshit C. , Paul Mausumi , Paul Santanu , Das Saurabh
Published: January 2011

Anthracycline drugs show anticancer activity, an ability to inhibit DNA replication and RNA transcription but are costly. This study attempts to see if cheaper hydroxy‐9,10‐anthraquinones (1,2,4‐trihydroxy‐9,10‐anthraquinone) that structurally resemble anthracyclines mimic its biological interactions and whether it can be a suitable substitute. Proton dissociation at 298 K for THA, pK1 = 4.82 ± 0.05 (phenolic OH at C2) and particularly pK2 = 9.22 ± 0.05 (phenolic OH at C1 and C4) closely resemble those of the anthracyclines. THA undergoes a single step two‐electron reduction in aqueous media (pH 7.36) having E1/2 = −0.69 V and two successive single‐electron reduction in DMF having E1/2 values −0.70 V and −1.06 V, respectively. CV data showed quasi‐reversible nature of THA in aqueous media. E1/2 values of THA were comparable to anthracycline drugs suggesting similarity in redox behavior. Binding studies of THA to ct DNA using UV–Vis and fluorescence spectroscopy were analyzed. Intrinsic binding constant and site size of interaction were (4.80 ± 0.2) × 104 M−1 and (5.96 ± 0.3) bases, respectively. THA, approximately three to five times weaker in binding ct DNA than anthracycline anticancer drugs suggests a role for sugar moieties present in anthracyclines. Anti‐leukemic activity studies of THA on cultured MOLT‐4 cell lines were performed and apoptosis measured by MTT assay. Result indicates THA to be a potent inducer of apoptosis in MOLT‐4 cell line having an IC50 value of 33.8 µM. THA therefore possesses anti‐leukemic activity that is comparable to anthracyclines on P388 leukemia and the study reveals that 1,2,4‐trihydroxy‐9,10‐anthraquinone to be a suitable substitute to the costlier anthracyclines. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of macrocyclic molecular brushes with amphiphilic block copolymers as side chains
Authors: Fan Xiaoshan , Wang Guowei , Huang Junlian
Published: February 2011

Macrocyclic molecular brushes c‐PHEMA‐g‐(PS‐b‐PEO) consisting of macrocyclic poly(2‐hydroxylethyl methacrylate) (c‐PHEMA) as backbone and polystyrene‐b‐poly(ethylene oxide) (PS‐b‐PEO) amphiphilic block copolymers as side chains were synthesized by the combination of atom transfer radical polymerization (ATRP), click chemistry, and single‐electron transfer nitroxide radical coupling (SET‐NRC). First, a linear α‐alkyne‐ω‐azido heterodifunctional PHEMA (l‐HCC‐PHEMA‐N3) was prepared by ATRP of HEMA using 3‐(trimethylsilyl)propargyl 2‐bromoisobutyrate as initiator, and then chlorine end groups were transformed to N3 group by nucleophilic substitution reaction in DMF in the presence of an excess of NaN3. The 3‐trimethylsilyl groups could be removed in the presence of tetrabutylammonium fluoride, and the product was cyclized by “click” chemistry in high dilution conditions. The hydroxyl groups on c‐PHEMA were transferred into bromine groups by esterification with 2‐bromoisobutyryl bromide and then initiate the ATRP of styrene. The formed macrocyclic molecular brushes c‐PHEMA‐g‐PS were coupled with the TEMPO‐PEO to afford the target macrocyclic molecular brushes c‐PHEMA‐g‐(PS‐b‐PEO) by SET‐NRC, and the efficiency is as high as 80∼85%. All of the intermediates and final product were characterized with 1H NMR, Fourier transform infrared (FTIR), and gel permeation chromatography in details © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Synthesis and characterization of ABA‐type amphiphilic tri‐block copolymers through anionic polymerization using end functionalized poly(ethylene oxide) oligomers
Authors: Das Palash Jyoti , Barak Anil , Kawakami Yusuke , Kannan Tharanikkarasu
Published: February 2011

ABA‐type amphiphilic tri‐block copolymers were successfully synthesized from poly(ethylene oxide) derivatives through anionic polymerization. When poly(styrene) anions were reacted with telechelic bromine‐terminated poly(ethylene oxide) (1) in 2:1 mole ratio, poly(styrene)‐b‐poly(ethylene oxide)‐b‐poly(styrene) tri‐block copolymers were formed. Similarly, stable telechelic carbanion‐terminated poly(ethylene oxide), prepared from 1,1‐diphenylethylene‐terminated poly (ethylene oxide) (2) and sec‐BuLi, was also used to polymerize styrene and methyl methacrylate separately, as a result, poly (styrene)‐b‐poly(ethylene oxide)‐b‐poly(styrene) and poly (methyl methacrylate)‐b‐poly(ethylene oxide)‐b‐poly(methyl methacrylate) tri‐block copolymers were formed respectively. All these tri‐block copolymers and poly(ethylene oxide) derivatives, 1 and 2, were characterized by spectroscopic, calorimetric, and chromatographic techniques. Theoretical molecular weights of the tri‐block copolymers were found to be similar to the experimental molecular weights, and narrow polydispersity index was observed for all the tri‐block copolymers. Differential scanning calorimetric studies confirmed the presence of glass transition temperatures of poly(ethylene oxide), poly(styrene), and poly(methyl methacrylate) blocks in the tri‐block copolymers. Poly(styrene)‐b‐poly(ethylene oxide)‐b‐poly(styrene) tri‐block copolymers, prepared from polystyryl anion and 1, were successfully used to prepare micelles, and according to the transmission electron microscopy and dynamic light scattering results, the micelles were spherical in shape with mean average diameter of 106 ± 5 nm. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Distress screening in allogeneic hematopoietic stem cell (HSCT) caregivers and patients
Authors: Bevans Margaret , Wehrlen Leslie , Prachenko Olena , Soeken Karen , Zabora James , Wallen Gwenyth R.
Published: February 2011

Family caregivers of allogeneic hematopoietic stem cell transplant (HSCT) patients are at risk for experiencing significant psychological distress yet screening caregivers has not been well studied.

Objective: This analysis explored the psychometric characteristics of the Distress Thermometer (DT) by examining its relationship, sensitivity, and specificity relative to the Brief Symptom Inventory 18 (BSI‐18) and the Multidimensional Fatigue Symptom Inventory (MFSI) in a sample of allogeneic HSCT caregivers and patients.

Methods: Longitudinal data were drawn from an ongoing intervention study for HSCT caregivers and patients. Data from one hundred and fifty‐six English‐speaking adults where patients (n = 65) were receiving their first allogeneic HSCT with at least one adult caregiver (n = 91) were eligible for this analysis. Study questionnaires were administered at baseline, initial discharge, and 6 weeks following discharge.

Results: Construct validity was supported by significant relationships (p<0.001) between the DT and the BSI‐18 GSI and the MFSI‐Emotional subscales for caregivers and patients. The diagnostic utility of the DT for patients was good (AUC = 0.85±0.05, p = 0.001), while for caregivers it was poor (AUC = 0.61±0.08, p = 0.28). A DT cut point of 5 was supported for patients (sensitivity = 1.0, specificity = 0.68), while for caregivers there was less confidence (sensitivity = 0.70, specificity = 0.52). Caregivers and patients reporting a higher number of problems had a greater level of distress (p<0.001).

Conclusions: These findings support the validity of the DT in screening for distress in HSCT caregivers and patients. Although the diagnostic utility of the DT for HSCT caregivers may be limited, understanding factors associated with distress can guide practice for this understudied population. Copyright © 2011 John Wiley & Sons, Ltd.
Seasonal variability of sleep‐disordered breathing in children
Authors: Gozal David , Shata Ahmad , Nakayama Meiho , Spruyt Karen
Published: January 2011

Introduction

Snoring and sleep‐disordered breathing (SDB) are frequent pediatric conditions. Although allergies and respiratory viruses have been pathophysiologically implicated in these conditions, their seasonal distribution has not been examined.

Methods

The records of all children participating in a prospective, cross‐sectional community‐based research study that included a questionnaire on snoring frequency and loudness and an overnight sleep study were retrospectively assessed for seasonal patterns based on the day the children were evaluated.

Results

A total of 1,051 children were included with a mean age of 7 years. There were no seasonal differences in the number of children evaluated or in their demographic characteristics. However, the odds of increased snoring frequency and loudness were significantly higher in spring and summer and lowest in fall (P < 0.001). However, the mean AHI was highest and the nadir SaO2 was lowest in winter and spring compared to summer and fall (P < 0.001 and P < 0.03, respectively).

Conclusion

Snoring and the severity of SDB exhibit distinct and essentially non‐overlapping patterns of seasonal variation, with peaks in spring–summer for snoring and peaks in winter‐spring for SDB severity. These findings suggest that both seasonal viral and allergen burdens may contribute to SDB severity and may prompt differing clinical referral patterns throughout the year. Pediatr. Pulmonol. 2011; 46:581–586. © 2011 Wiley‐Liss, Inc.
Synthesis and characterization of high energy compounds. I. Trans‐1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin (TNAD)
Authors: Wilier R. L.
Published: January 2011

The synthesis of a new high‐energy compound trans‐1,4,5,8‐tetranitro‐1,4,5,8‐tetraazadecalin is described. The compound has a density of 1.80 g/cm3 and a heat of formation of 17.5 kcal/mol. The detonation pressure is calculated to be 310 kbar and the detonation velocity is calculated to be 8.36 mm/μs by the Kamlet Short Method.
A hexahydro‐1,3,5‐trinitro‐l,3,5‐triazine (RDX): ϵ‐caprolactone adduct
Authors: Selig W. , Bruenner R. S. , Price H. A.
Published: January 2011

A new unstable equimolar adduct of hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine was formed with 6‐hexanolactone (ϵ‐caprolactone). Some properties of the adduct are presented.
Rapid determination of nitrogen in nitrocellulose of smokeless ball propellants
Authors: Lilliott E. L. , Sterling G. H.
Published: January 2011

The nitrogen analyzer method described here is an excellent alternate to the currently acceptable procedures for percent nitrogen in ball powder. It offers the advantages of greatly reduced analysis time, negligible exposure to mercury, minimum exposure to nitrocellulose, no exposure to sulfuric acid and toxic oxides of nitrogen gases. Analyzer method is currently used for ball powder, but experimental work is continuing on other propellants, nitroglycerin, and nitrating acids. The authors propose this method be accepted as an alternate method for nitrogen content in ball powder.
Room temperature cured polyurea‐urethane propellant with unique mechanical properties
Authors: Muthiah Rm. , John B. , Somasundaram U. I.
Published: January 2011

A polyurea‐urethane propellant based on an NCO‐terminated prepolymer, a diamine and a triol has been developed. This is a room temperature curing propellant which is case‐bondable. This has been standardized at 3‐kg level and then scaled upto grains of 300‐mm diameter and 2250‐mm length weighing 250 kg. This propellant has a tensile strength of about 4 kg/cm2 and an elongation of 150 percent. Because of low cost, case bondability and room temperature curability this can be used in large solid boosters.
Precise assay of TATB by the determination of total amino and nitro functional groups
Authors: Rigdon L. P. , Stephens F. B. , Harrar J. E.
Published: January 2011

Methods have been developed for the precise assay of the explosive l,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB) using procedures that quantitatively measure total nitro and/or total amino functional groups. The method for the determination of total nitro groups is based on the dissolution of TATB in DMSO‐NaOH, electrolytic reduction of ‐NO2 to ‐NH2, and measurement by controlled‐potential coulometry. The reduction is carried out at a mercury pool electrode at −0.60 V versus standard calomel electrode (SCE) in a supporting electrolyte 1 M in H3PO4 and 3 M in HClO4. Background corrections are low, and samples containing 0.1 mg to 2 mg of TATB per ml can be analyzed with a precision and accuracy of 0.25% to 0.5%.

The method for determining total amino groups is based on the conversion of ‐NH2 to NH3 in a Kjeldahl‐type apparatus. The sample does not require an acid digestion step. The ‐ NH2 groups are readily converted to NH3 and distilled from a solution of NaOH and dimethylsulfoxide (DMSO). Individual samples of 120 mg‐170 mg of TATB can be conveniently assayed for amino groups with an accuracy and precision of about 0.25%.
Synthesis, structural, and optical properties of core/shell ZnS:Fe/ZnS nanocrystals
Authors: Liu Lingyun , Xie Ruishi , Yang Lin , Xiao Dingquan , Zhu Jianguo
Published: February 2011

ZnS:Fe/ZnS core/shell nanocrystals (NCs) were synthesized by a simple liquid‐solid‐solution (LSS) method and the influence of ZnS shell thickness on the optical properties of ZnS:Fe/ZnS NCs was investigated. The crystalline and optical properties of ZnS:Fe/ZnS core/shell NCs were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, UV–Visible spectrometer and FT‐IR spectrometer, respectively. It was found that the ZnS:Fe/ZnS core/shell NCs are highly crystalline and show zincblende structure with an average particle size of about 7 nm. The lattice constants of the ZnS:Fe/ZnS NCs decrease slightly by the introduction of Fe, and the Fe dopants were well doped into the ZnS:Fe/ZnS NCs, as confirmed by XPS. Compared to the pure ZnS:Fe NCs, the ZnS:Fe/ZnS core/shell NCs exhibited significantly enhanced luminescence properties. A red‐shift can be observed in the absorption and PL spectra as the ZnS shells thickened.
Longitudinal analysis of large social networks: Estimating the effect of health traits on changes in friendship ties
Authors: O'Malley A. James , Christakis Nicholas A.
Published: February 2011

We develop novel mixed effects models to examine the role of health traits on the status of peoples' close friendship nominations in the Framingham Heart Study. The health traits considered are both mutable (body mass index (BMI), smoking, blood pressure, body proportion, muscularity, and depression) and, for comparison, basically immutable (height, birth order, personality type, only child, and handedness); and the traits have varying degrees of observability. We test the hypotheses that existing ties (i.e. close friendship nominations) are more likely to dissolve between people with dissimilar (mutable and observable) health traits whereas new ties are more likely to form between those with similar (mutable and observable) traits while controlling for persons' age, gender, geographic separation, and education. The mixed effects models contain random effects for both the nominator (ego) and nominated (alter) persons in a tie to account for the fact that people were involved in multiple relationships and contributed observations at multiple exams. Results for BMI support the hypotheses that people of similar BMI are less likely to dissolve existing ties and more likely to form ties, while smoker to non‐smoker ties were the least likely to dissolve and smoker to smoker ties were the most likely to form. We also validated previously known findings regarding homophily on age and gender, and found evidence that homophily also depends upon geographic separation. Copyright © 2011 John Wiley & Sons, Ltd.
Eine einfache Theorie der Hertzschen Pressung
Authors: Rosemeier Gustav‐Erich
Published: January 2011

Kontaktprobleme treten im Stahlbau z. B. bei Brückenlagern, aber auch bei geotechnischen Problemen z. B. bei Fundamentbemessungen auf. Hierbei sind analytische Lösungen teilweise in Näherung möglich, wobei sich diese Rechenmethoden zunehmend zu allgemein gültigen Computerverfahren umstellen. In diesem Beitrag soll ein vereinfachtes Rechenverfahren vorgestellt werden, das in Näherung zur Ergebniskontrolle geeignet ist.

A simplified theory of the Hertz pressure. We have contact problems in structural mechanics f. e. of steel structures or dimensioning of foundations. It is possible sometimes to find approximate analytical solutions, but the trend is to transform these arithmetical operations to computer procedures. This contribution wants to represent a simplified model to check the results.
Narrowed beam width in newer ultrasound machines shortens measurements in the lateral direction: fetal measurement charts may be obsolete
Authors: Økland I. , Bjåstad T. G. , Johansen T. F. , Gjessing H. K. , Grøttum P. , Eik‐Nes S. H.
Published: January 2011

Objectives

Fetal ultrasound measurements are made in axial, lateral and oblique directions. Lateral resolution is influenced by the beam width of the ultrasound system. To improve lateral resolution and image quality, the beam width has been made narrower; consequently, measurements in the lateral direction are affected and apparently made shorter, approaching the true length. The aims of this study were to explore our database to reveal time‐dependent shortening of ultrasound measurements made in the lateral direction, and to assess the extent of beam‐width changes by comparing beam‐width measurements made on old and new ultrasound machines.

Methods

A total of 41 941 femur length measurements, collected during the time‐period 1987–2005, were analyzed, with time as a covariate. Using three ultrasound machines from the 1990s and three newer machines from 2007, we performed 25 series of blinded beam‐width measurements on a tissue‐mimicking phantom, measuring at depths of 3–8 cm with a 5‐MHz transducer.

Results

Regression analysis showed time to be a significant covariate. At the same gestational age, femur length measurement was 1.15 (95% CI, 1.08–1.23) mm shorter in the time‐period 1999–2005 than in the time‐period 1987–1992. Overall, the beam width was 1.08 (95% CI, 0.50–1.65) mm narrower with the new machines than with the old machines.

Conclusions

Technical improvements in modern ultrasound machines that have reduced the beam width affect fetal measurements in the lateral direction. This has clinical implications and new measurement charts are needed. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Sequential frequency reuse with power control for OFDMA systems
Authors: Choi Bumkwi , Lim Seyoun , Lee Tae‐Jin
Published: February 2011

Orthogonal frequency division multiple access (OFDMA) is a promising technique for high data rate communications in future cellular systems. Since frequency resources are universally reused in every cell in a system, a typical OFDMA system tries to maximize the spectral efficiency. Users located near the cell‐edge tend to have the weakest signal strength. So they might experience severe inter‐cell interferences (ICIs). In this paper, we propose a sequential frequency reuse (SqFR) that reduces ICIs by a sequential sub‐channel allocation. By giving more power to sub‐carriers allocated to cell‐edge users, our SqFR significantly enhances the performance of cell‐edge users. The performance of the proposed SqFR is investigated via the analysis and simulations. Simulation results show that proposed SqFR improves the performance of cell‐edge users in an OFDMA system under both homogeneous and heterogeneous traffic conditions. Copyright © 2011 John Wiley & Sons, Ltd.
Joint collision resolution and transmit‐power adjustment for Aloha‐type random access
Authors: Choi Young‐June , Shin Kang G.
Published: January 2011

We consider uplink random access for which slotted Aloha has usually been employed with unknown channel conditions. Upon failure of a transmission attempt, a user cannot tell whether the failure was caused by collision with other simultaneously transmitting users or by his use of insufficient transmit power. If a transmission attempt failed due to collision which could have been resolved by retransmission, increasing transmit power would just waste power and, moreover, reduce the other users' chance of successful access. To handle this lack of information on the cause of failure, we propose a novel Cause‐of‐Failure resolution, where the transmit power is increased after a given number of consecutive unsuccessful access attempts when the probability that a given failure is caused by collision becomes sufficiently low. To exploit the thus‐obtained transmit power for the next random access attempt, we also determine the Cause‐of‐Success based on the number of consecutive successful attempts, i.e., whether to (probabilistically) decrease or maintain the current transmit power. This way, users can adjust their transmit power for random access, which we call Auto Power Fallback (APF), considered as an advanced version of the power ramping algorithm. We evaluate APF by modeling analysis and numerical computation based on the slotted Aloha, showing that APF determines a suitable transmit power for uplink random accesses while achieving good performance. Copyright © 2011 John Wiley & Sons, Ltd.
Parenting a child with phenylketonuria or galactosemia: implications for health‐related quality of life
Authors: ten Hoedt Amber E. , Maurice‐Stam Heleen , Boelen Carolien C. A. , Rubio‐Gozalbo M. Estela , van Spronsen Francjan J. , Wijburg Frits A. , Bosch Annet M. , Grootenhuis Martha A.
Published: February 2011

Parents of children with chronic disorders have an impaired health‐related quality of life (HRQoL) compared to parents of healthy children. Remarkably, parents of children with a metabolic disorder reported an even lower HRQoL than parents of children with other chronic disorders. Possibly, the uncertainty about the course of the disease and the limited life expectancy in many metabolic disorders are important factors in the low parental HRQoL. Therefore, we performed a cross‐sectional study in parents of children with phenylketonuria (PKU, OMIM #261600) and galactosemia (OMIM #230400), metabolic disorders not affecting life expectancy, in order to investigate their HRQoL compared to parents of healthy children and to parents of children with other metabolic disorders. A total of 185 parents of children with PKU and galactosemia aged 1–19 years completed two questionnaires. Parents of children with PKU or galactosemia reported a HRQoL comparable to parents of healthy children and a significantly better HRQoL than parents of children with other metabolic disorders. Important predictors for parental mental HRQoL were the psychosocial factors emotional support and loss of friendship. As parental mental functioning influences the health, development and adjustment of their children, it is important that treating physicians also pay attention to the wellbeing of the parents. The insight that emotional support and loss of friendship influence the HRQoL of the parents enables treating physicians to provide better support for these parents.