bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractABA‐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

AbstractFamily 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

AbstractIntroductionSnoring 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.MethodsThe 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.ResultsA 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).ConclusionSnoring 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

AbstractThe 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

AbstractA 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

AbstractThe 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

AbstractA 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

AbstractMethods 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

AbstractZnS: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

AbstractWe 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

AbstractKontaktprobleme 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

AbstractObjectivesFetal 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.MethodsA 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.ResultsRegression 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.ConclusionsTechnical 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

ABSTRACTOrthogonal 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

ABSTRACTWe 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

AbstractParents 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.
Advances and challenges in the treatment of branched‐chain amino/keto acid metabolic defects
Authors: Knerr Ina , Weinhold Natalie , Vockley Jerry , Gibson K. Michael 
Published: February 2011

SummaryDisorders of branched‐chain amino/keto acid metabolism encompass diverse entities, including maple syrup urine disease (MSUD), the ‘classical’ organic acidurias isovaleric acidemia (IVA), propionic acidemia (PA), methylmalonic acidemia (MMA) and, among others, rarely described disorders such as 2‐methylbutyryl‐CoA dehydrogenase deficiency (MBDD) or isobutyryl‐CoA dehydrogenase deficiency (IBDD). Our focus in this review is to highlight the biochemical basis underlying recent advances and ongoing challenges of long‐term conservative therapy including precursor/protein restriction, replenishment of deficient substrates, and the use of antioxidants and anaplerotic agents which refill the Krebs cycle. Ongoing clinical assessments of affected individuals in conjunction with monitoring of disease‐specific biochemical parameters remain essential. It is likely that mass spectrometry‐based ‘metabolomics’ may be a helpful tool in the future for studying complete biochemical profiles and diverse metabolic phenotypes. Prospective studies are needed to test the effectiveness of adjunct therapies such as antioxidants, ornithine‐alpha‐ketoglutarate (OKG) or creatine in addition to specialized diets and to optimize current therapeutic strategies in affected individuals. With the individual life‐time risk and degree of severity being unknown in asymptomatic individuals with MBDD or IBDD, instructions regarding risks for metabolic stress and fasting avoidance along with clinical monitoring are reasonable interventions at the current time. Overall, it is apparent that carefully designed prospective clinical investigations and multicenter cohort‐controlled trials are needed in order to leverage that knowledge into significant breakthroughs in treatment strategies and appropriate approaches.
Evaluation of high density lipoprotein as a circulating biomarker of Gaucher disease activity
Authors: Stein Philip , Yang Ruhua , Liu Jun , Pastores Gregory M. , Mistry Pramod K. 
Published: February 2011

AbstractCirculating biomarkers are important surrogates for monitoring disease activity in type I Gaucher disease (GD1). We and others have reported low high‐density lipoprotein (HDL) in GD1. We assessed HDL cholesterol as a biomarker of GD1, with respect to its correlation with indicators of disease severity and its response to imiglucerase enzyme replacement therapy (ERT). In 278 consecutively evaluated GD1 patients, we correlated HDL cholesterol, chitotriosidase, and angiotensin‐converting enzyme (ACE) with indicators of disease severity. Additionally, we measured the response of these biomarkers to ERT. HDL cholesterol was negatively correlated with spleen volume, liver volume, and GD severity score index; the magnitude of this association of disease severity with HDL cholesterol was similar to that for ACE and for chitotriosidase. Within individual patients monitored over many years, there was a strikingly strong correlation of HDL with liver and spleen volumes; there was a similarly strong correlation of chitotriosidase and ACE with disease severity in individual patients monitored serially over many years (chitotriosidase r = 0.96 to 0.98, ACE r  = 0.88 to 0.94, and HDL r = −0.84 to −0.94, p < 0.001). ERT for 3 years resulted in a striking increase of HDL while serum levels of chitotriosidase and ACE decreased. Our results reveal markedly low HDL cholesterol in untreated GD1, a correlation with indicators of disease severity in GD1, and a rise towards normal after ERT. These findings suggest HDL cholesterol merits inclusion within the “biomarker basket” for monitoring of patients with GD1.