bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigating Interfacial Contributions on the Layer‐Thickness‐Dependent Mechanical Response of Confined Self‐Assembly via Forced Assembly
Authors: Burt Tiffani M. , Jordan Alex M. , Korley LaShanda T. J. 
Published: February 2013

AbstractUnderstanding block copolymer (BCP) self‐assembly under confinement via conventional melt extrusion is advantageous as technology moves towards thin film applications. Previous research has revealed that confining elastomeric BCPs in thin films with polystyrene (PS) via microlayering results in an increase in ductility with decreasing layer thickness and that the interfacial region dramatically influences the elastic modulus. This contribution investigated the role of interfacial width and layer thickness on deformation mechanics by comparing poly(methyl methacrylate) (PMMA) and PS as wetting layers in confined multilayers. The interfacial region was found to be crucial to tailoring the mechanical response of composite materials.magnified image
Collapse of Cylindrical Brushes with 2‐Isopropyloxazoline Side Chains Close to the Phase Boundary
Authors: Bühler Jasmin , Muth Sandra , Fischer Karl , Schmidt Manfred 
Published: February 2013

AbstractA high‐molar‐mass cylindrical brush polymer with a main chain degree of polymerization of Pw = 1047 is synthesized by free‐radical polymerization of a poly‐2‐isopropyloxazoline macromonomer with Pn = 28. The polymerization is conducted above the lower phase transition temperature of the macromonomer, i.e., in the phase‐separated regime, which provides a sufficiently concentrated macromonomer phase mandatory to obtain high‐molar‐mass cylindrical brushes. Upon heating to the phase transition temperature, the hydrodynamic radius is observed to shrink from 34 to 27 nm. Further increase in temperature resulted in aggregated chains which were observed to coexist with single chains until eventually only aggregates of μm size were detectable.magnified image
An economic model of Parkinson's disease: Implications for slowing progression in the United States
Authors: Johnson Scott J. , Diener Melissa D. , Kaltenboeck Anna , Birnbaum Howard G. , Siderowf Andrew D. 
Published: February 2013

ABSTRACTMultiple studies describe progression, dementia rates, direct and indirect costs, and health utility by Hoehn and Yahr (H&Y) stage, but research has not incorporated these data into a model to evaluate possible economic consequences of slowing progression. This study aimed to model the course of Parkinson's disease (PD) and describe the economic consequences of slower rates of progression. A Markov model was developed to show the net monetary benefits of slower rates of progression. Four scenarios assuming hypothetical slower rates of progression were compared to a base case scenario. A systematic literature review identified published longitudinal H&Y progression rates. Direct and indirect excess costs (i.e., healthcare costs beyond what similar patients without PD would incur), mortality rates, dementia rates, and health utility were derived from the literature. Ten publications (N = 3,318) were used to model longitudinal H&Y progression. Base case results indicate average excess direct costs of $303,754, life‐years of 12.8 years and quality‐adjusted life‐years of 6.96. A scenario where PD progressed 20% slower than the base case resulted in net monetary benefits of $60,657 ($75,891 including lost income) per patient. The net monetary benefit comes from a $37,927 decrease in direct medical costs, 0.45 increase in quality‐adjusted life‐years, and $15,235 decrease in lost income. The scenario where PD progression was arrested resulted in net monetary benefits of $442,429 per patient. Reducing progression rates could produce significant economic benefit. This benefit is strongly dependent on the degree to which progression is slowed. © 2013 Movement Disorder Society
The impact of a managed transition of care upon psychosocial characteristics and patient satisfaction in a cohort of adult survivors of childhood cancer
Authors: van Laar M. , Glaser A. , Phillips R. S. , Feltbower R. G. , Stark D. P. 
Published: February 2013

AbstractObjectiveMany adult survivors of childhood cancer receive care in paediatric departments, despite national policy to transition their care to adult services. When long‐term follow‐up care for survivors of childhood cancer in our region moved from a paediatric to an adult environment in 2009, we prospectively assessed the impact of this change on patient satisfaction.MethodsQuestionnaire data were collected in paediatric and adult clinical environments regarding the level of satisfaction with care and potential mediators: quality of life, psychological health and social difficulties. Predictors of satisfaction and optimum longitudinal risk‐based care were described using path analysis and compared with previously described models.ResultsThere was no significant difference in satisfaction between the paediatric and adult settings. Short waiting times and increased understanding of the purpose of follow‐up were significantly associated with increased satisfaction. Those with a higher perception of health problems and those that were older were more likely to not attend all of their clinic appointments.ConclusionsWithin our service, transition to adult care did not impact significantly upon patient satisfaction. Shorter waits and knowing why participants were attending the clinic increased satisfaction. Joint working between adult and paediatric cancer professionals enabled adult survivors of childhood cancer to receive highly satisfactory care in adult services. Copyright © 2013 John Wiley & Sons, Ltd.
Influence of protein immobilization on protein–protein interaction measured by scanning force spectroscopy
Authors: Rösch Christina , Huber Christina , Müller Christine , Umanskaya Natalia , Hannig Matthias , Ziegler Christiane 
Published: February 2013

AbstractFor a better understanding of biofilm establishment, adhesion forces of proteins on immobilized protein layers were investigated by scanning force spectroscopy (SFS). For this purpose the experimental setup to immobilize protein layers on the surface is important. The influence of the method chosen to immobilize the proteins on the surface was examined and afterwards the effect of variations in pH and contact time on the measured adhesion forces in protein–protein interaction was analyzed. The adsorption of bovine serum albumin (BSA) on BSA‐coated silicon was used here as a model system. To coat the substrate, free adsorption, crosslinking with glutaraldehyde, and covalent protein binding to the surface after silanization were used. For the latter different deposition methods of the silane were compared. Depending on the immobilization method the measured protein–protein interactions show distinct differences. Covalent attachment of proteins is a promising approach to attain stable, pre‐adsorbed protein layers for SFS measurements. The adhesion forces of a BSA‐coated cantilever on such layers seem to be dominated by electrostatic interactions of the molecules.
Highly enhanced luminescence of SrSi2O2N2:Eu2+ phosphors by Mg2+ substitution and their application in pc‐LED
Authors: Lee Sun‐Hee , Kim Kwang‐Bok , Kim Jong‐Moon , Jeong Yong‐Kwang , Kang Jun‐Gill 
Published: February 2013

AbstractThe effect of substitution of Sr2+ by Mg2+ on the luminescence properties of (Sr0.9 − xMgx)Si2O2N2:0.1Eu2+ were investigated as a function of the concentration of Mg2+(x). The peak position of the yellowish green emission from (Sr0.9 − xMgx)Si2O2N2:0.1Eu2+ was invariant with x. However, the luminescence intensity was significantly affected by x. With increasing Mg2+ concentration, the intensity increased to a maximum at x = 0.1. Partial substitution of Sr2+ by Mg2+ enhanced the intensity 1.8‐fold. The Eu2+ concentration affected the peak positions of both luminescence and excitation. With increasing Eu2+ concentration, the red‐shifting and enhancement of the luminescence were associated with the nephelauxetic effect. Concentration quenching of the luminescence occurred above y = 0.07 in the (Sr0.8 − yMg0.1)Si2O2N2:yEu2+. Above the critical concentration of Eu2+, non‐radiative transitions between adjacent Eu2+ ions were more effective than the nephelauxetic effect. Optimized (Sr0.83Mg0.1)Si2O2N2:0.07Eu2+ phosphors were fabricated with blue GaN LED and the chromaticity index of the phosphor‐formulated GaN LED was investigated as a function of the wt% of the optimized phosphor.
Evaluation of reagentless pH modification for in situ ocean analysis: determination of dissolved inorganic carbon using mass spectrometry
Authors: Cardenas‐Valencia Andres M. , Adornato Lori R. , Bell Ryan J. , Byrne Robert H. , Short R. Timothy 
Published: February 2013

RATIONALEIn situ analytical techniques that require the storage and delivery of reagents (e.g., acidic or basic solutions) have inherent durability limitations. The reagentless electrolytic technique for pH modification presented here was developed primarily to ease and to extend the longevity of dissolved inorganic carbon (DIC) determinations in seawater, but can also be used for other analytical methods. DIC, a primary carbon dioxide (CO2) system variable along with alkalinity, controls seawater pH, carbonate saturation state, and CO2 fugacity. Determinations of these parameters are central to an understanding of ocean acidification and global climate change.METHODSElectrodes fabricated with electroactive materials, including manganese(III) oxide (Mn2O3) and palladium (Pd), were examined for potential use in electrolytic acidification. In‐line acidification techniques were evaluated using a bench‐top membrane introduction mass spectrometry (MIMS) setup to determine the DIC content of artificial seawater. Linear least‐squares (LLSQ) calibrations for DIC concentration determinations over a range between 1650 and 2400 µmol kg–1 were obtained, using both the novel electrolytic and conventional acid addition techniques.RESULTSAt sample rates of 4.5 mL min–1, electrodes clad with Mn2O3 and Pd were able to change seawater pH from 7.6 to 2.8 with a power consumption of less than 3 W. Although calibration curves were influenced by sampling rates at a flow of 4.5 mL min–1, the 1σ measurement precision for DIC was of the order of ±20 µmol kg–1.CONCLUSIONSCalibrations obtained with the novel reagentless technique and the in‐line addition of strong acid showed similar capabilities for DIC quantification. However, calculations of power savings for the reagentless technique relative to the mechanical delivery of stored acid demonstrated substantial advantages of the electrolytic technique for long‐term deployments (>1 year). Copyright © 2013 John Wiley & Sons, Ltd.
Background effects on Faraday collectors in gas‐source mass spectrometry and implications for clumped isotope measurements
Authors: Bernasconi Stefano M. , Hu Bin , Wacker Ulrike , Fiebig Jens , Breitenbach Sebastian F. M. , Rutz Tanja 
Published: February 2013

RATIONALEThe measurement of the abundances of minor isotopologues by mass spectrometry requires correction of subtle non‐linearities in the mass spectrometer that cause deviations in the relationship between actual and measured isotope ratios. Here we show that negative backgrounds on the Faraday cups recording the minor ion beams are the cause of the observed non‐linearities in the measurement of CO2 isotopologues, and propose a new correction procedure for clumped isotope measurements.METHODSWe carefully investigated the cause of non‐linearity effects in the measurement of the abundance of 13C18O16O, a minor isotopologue of CO2 with m/z 47, on two different mass spectrometers. By using gases of different composition with close to stochastic and with non‐random distribution of isotopes we demonstrate that the apparent dependence of the excess abundance of the isotopologue of m/z 47 on the bulk isotopic composition of CO2 is due to a background interference that is linearly dependent on the partial pressure of the gas in the source of the mass spectrometer.CONCLUSIONSBackground determination with gas flowing into the source of the mass spectrometer is necessary for accurate clumped isotope measurements of CO2. Background corrections can be performed accurately if the slit width of the m/z 44 Faraday cup significantly exceeds that of the one for m/z 47, using a correlation between m/z 44 signal intensity and the corresponding minimum in m/z 47 background. We propose two new correction schemes that reduce the time‐consuming measurement of gases of different bulk isotopic compositions. These findings may also be relevant for the measurement of other rare isotopologues by mass spectrometry. Copyright © 2013 John Wiley & Sons, Ltd.
Teachers’ Nature of Science Implementation Practices 2–5 Years After Having Completed an Intensive Science Education Program
Authors: HERMAN BENJAMIN C. , CLOUGH MICHAEL P. , OLSON JOANNE K. 
Published: February 2013

ABSTRACTFew, if any, studies have examined the impact of nature of science (NOS) instruction on science teachers’ practices 2 or more years after completing a science teacher education program. Extant studies on preservice and first‐year teachers’ NOS teaching practices have had disappointing results, with few teachers valuing NOS as a cognitive objective or teaching it in ways consistent with literature regarding effective NOS instruction. In addition, little is known about teachers’ specific NOS practices due to a lack of observation protocols to assess teachers’ NOS instruction. This study examined teachers’ NOS instructional practices 2–5 years after completing an intensive secondary science education program that included a NOS course and attention to NOS instruction throughout all other science education coursework. Twelve of the 13 study participants explicitly taught NOS, and 9 of the 13 did so at moderate to high levels. This paper also presents a NOS Classroom Observation Protocol (NOS‐COP) designed to make evident many facets of teachers’ NOS implementation practices that have not always been clear in prior research. This study raises important issues about achieving the goal of NOS instruction. Accurate and effective NOS instruction appears achievable, but may require far more effort than found in typical science teacher education programs. © 2013 Wiley Periodicals, Inc. Sci Ed 97:271–309, 2013
Becoming Researchers: The Participation of Undergraduate and Graduate Students in Scientific Research Groups
Authors: FELDMAN ALLAN , DIVOLL KENT A. , ROGAN‐KLYVE ALLYSON 
Published: February 2013

ABSTRACTThis study sought to understand how graduate and undergraduate students learn to do science by participating in research groups. A phenomenological approach was used to illuminate the experiences of the students. The results provide evidence that the students were in the role of apprentices, although this was not made explicit. As apprentices they learned by doing as legitimate peripheral participants in the groups. Mentoring was distributed among the group, with more advanced students providing much of it. The groups were both communities of practice and epistemic communities in which students gained methodological and intellectual proficiency. Finally, student learning in research groups can be conceptualized as learning trajectories that enter the group, traverse characteristics of communities of practice and epistemic communities, and leave with the students as novice researchers, proficient technicians, or knowledge producers. The implications for K‐12 science education are that it is unrealistic to expect teachers to achieve the proficiency in traditional short‐term research experiences that would prepare them to teach their students how to engage in authentic scientific research, and that these experiences should be structured so that the teachers are placed in tightly organized research groups with mentors who explicitly teach them how to do science. © 2013 Wiley Periodicals, Inc. Sci Ed 97:218–243, 2013
AdS field theory from conformal field theory
Authors: Fitzpatrick A. Liam , Kaplan Jared 
Published: February 2013

Abstract

We provide necessary and sufficient conditions for a Conformal Field Theory to have a description in terms of a perturbative Effective Field Theory in AdS. The first two conditions are well-known: the existence of a perturbative ‘1/N ’ expansion and an approximate Fock space of states generated by a finite number of low-dimension operators. We add a third condition, that the Mellin amplitudes of the CFT correlators must be well- approximated by functions that are bounded by a polynomial at infinity in Mellin space, or in other words, that the Mellin amplitudes have an effective theory-type expansion. We explain the relationship between our conditions and unitarity, and provide an analogy with scattering amplitudes that becomes exact in the flat space limit of AdS. The analysis also yields a simple connection between conformal blocks and AdS diagrams, providing a new calculational tool very much in the spirit of the S-Matrix program.
We also begin to explore the potential pathologies associated with higher spin fields in AdS by generalizing Weinberg’s soft theorems to AdS/CFT. The AdS analog of Weinberg’s argument constrains the interactions of conserved currents in CFTs, but there are potential loopholes that are unavailable to theories of massless higher spin particles in flat spacetime.
Liberian Surgical and Anesthesia Infrastructure: A Survey of County Hospitals
Authors: Knowlton Lisa Marie , Chackungal Smita , Dahn Bernice , LeBrun Drake , Nickerson Jason , McQueen Kelly 
Published: February 2013

AbstractBackgroundThere is a significant burden of disease in low‐income countries that can benefit from surgical intervention. The goal of this survey was to evaluate the current ability of the Liberian health care system to provide safe surgical care and to identify unmet needs in regard to trained personnel, equipment, infrastructure, and outcomes measurement.MethodsA comprehensive survey tool was developed to assess physical infrastructure of operative facilities, education and training for surgical and anesthesia providers, equipment and medications, and the capacity of the surgical system to collect and evaluate surgical outcomes at district‐level hospitals in Africa. This tool was implemented in a sampling of 11 county hospitals in Liberia (January 2011). Data were obtained from the Ministry of Health and by direct government‐affiliated hospital site visits.ResultsThe total catchment area of the 11 hospitals surveyed was 2,313,429—equivalent to roughly 67 % of the population of Liberia (3,476,608). There were 13 major operating rooms and 34 (1.5 per 100,000 population) physicians delivering surgical, obstetric, or anesthesia care including 2 (0.1 per 100,000 population) who had completed formal postgraduate training programs in these specialty areas. The total number of surgical cases for 2010 was 7,654, with approximately 43 % of them being elective procedures. Among the facilities that tracked outcomes in 2010, a total of 11 intraoperative deaths (145 per 100,000 operative cases) were recorded for 2009. The 30‐day postoperative mortality at hospitals providing data was 44 (1,359 per 100,000 operative cases). Metrics were also used to evaluate surgical output, safety of anesthesia, and the burden of obstetric disease.ConclusionsA significant volume of surgical care is being delivered at county hospitals throughout Liberia. The density and quality of appropriately trained personnel and infrastructure remain critically low. There is strong evidence for continued development of emergency and essential surgical services, as well as improved surgical outcomes tracking, at county hospitals in Liberia. These results serve to inform the international community and donors of the ongoing global surgical and anesthesia crisis.
Laparoscopic Surgical Skills are Significantly Improved by the Use of a Portable Laparoscopic Simulator: Results of a Randomized Controlled Trial
Authors: Johnston T. J. , Tang B. , Alijani A. , Tait I. , Steele R. J. , Ker J. , Nabi G. ,   Surgical Simulation Group at the University of Dundee
Published: February 2013

AbstractBackgroundThere is growing evidence that training on virtual reality simulators leads to improved performance in the animate and human operating room. However, they are expensive, have a limited availability, and involve complex systems. Portable simulators are significantly cheaper, more user‐friendly, and are flexible systems that are more suited to a surgical trainee’s busy schedule. The use of portable surgical simulators to train skills and reduce errors has never been evaluated in prospective, randomized clinical settings. The objective of this study was to determine if training on the portable Integrated Laparoscopic Simulator leads to improved performance of core laparoscopic skills.MethodsCore laparoscopic skills were identified by five experienced laparoscopic surgeons and modeled into two exercises and three basic tasks. Twenty surgically naive medical students had baseline laparoscopic skills assessed on a fixed simulator. Participants were randomized to either 14 h training on a portable laparoscopic simulator over a 3 week period, or control with no training. At 3 weeks two expert laparoscopic surgeons blinded to the allocation of participants assessed their pre‐ and post‐intervention performances recorded on a CD‐ROM. The outcome measures included time to complete and global rating scores of clipping and dissection tasks.ResultsNo differences were observed in baseline skills level between the two groups. The intervention group had better quality of scissors dissection (p = 0.0038) and improved clipping skills (p = 0.0051), and they took less time to accomplish the tasks (p = 0.0099) in comparison to control.ConclusionsTraining on the portable Integrated Laparoscopic Simulator significantly improved core laparoscopic skills in medical students with no prior experience.
Remittances in the Republic of Georgia: Correlates, Economic Impact, and Social Capital Formation
Authors: Gerber Theodore P. , Torosyan Karine 
Published: February 2013

AbstractThe economic impact of remittances on migrant-sending countries has been a subject of debate in the scholarly literature on migration. We consider the topic using a household-level approach. We use a new survey, “Georgia on the Move,” to examine migrant-level, household-level, and contextual variables associated with the probability that a household in the Republic of Georgia receives remittances. We then apply propensity score matching to estimate how remittances affect particular types of household expenditures, savings, labor supply, health, and other measures of well-being. Separate analysis of the subsample of households with a migrant currently abroad distinguishes the effects of remittances from the effects of migration as such. In Georgia, remittances improve household economic well-being without, for the most part, producing the negative consequences often suggested in the literature. We find evidence for an important aspect that has not been widely discussed in prior studies: remittances foster the formation of social capital by increasing the amount of money that households give as gifts to other households.