bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of covariate adjustment for baseline severity in acute stroke clinicaltrials with responder analysis outcomes
Authors: Garofolo Kyra M , Yeatts Sharon D , Ramakrishnan Viswanathan , Jauch Edward C , Johnston Karen C , Durkalski Valerie L 
Published: May 2013

Abstract

Background
Traditionally in acute stroke clinical trials, the primary clinical outcomeemployed is a dichotomized modified Rankin Scale (mRS). New statisticalmethods, such as responder analysis, are being used in stroke studies toaddress the concern that baseline prognostic variables, such as strokeseverity, impact the likelihood of a successful outcome. Responder analysisallows the definition of success to vary according to baseline prognosticvariables, producing a more clinically relevant insight into the actualeffect of investigational treatments. It is unclear whether or notstatistical analyses should adjust for prognostic variables when responderanalysis is used, as the outcome already takes these prognostic variablesinto account. This research aims to investigate the effect of covariateadjustment in the responder analysis framework in order to determine theappropriate analytic method.

Methods
Using a current stroke clinical trial and its pilot studies to guidesimulation parameters, 1,000 clinical trials were simulated at varyingsample sizes under several treatment effects to assess power and type Ierror. Covariate-adjusted and unadjusted logistic regressions were used toestimate the treatment effect under each scenario. In the case ofcovariate-adjusted logistic regression, the trichotomized National Instituteof Health Stroke Scale (NIHSS) was used in adjustment.

Results
Under various treatment effect settings, the operating characteristics of theunadjusted and adjusted analyses do not substantially differ. Power and typeI error are preserved for both the unadjusted and adjusted analyses.

Conclusions
Our results suggest that, under the given treatment effect scenarios, thedecision whether or not to adjust for baseline severity when using aresponder analysis outcome should be guided by the needs of the study, astype I error rates and power do not appear to vary largely between themethods. These findings are applicable to stroke trials which use the mRSfor the primary outcome, but also provide a broader insight into theanalysis of binary outcomes that are defined based on baseline prognosticvariables.

Trial registration
This research is part of the Stroke Hyperglycemia Insulin Network Effort(SHINE) trial, Identification Number NCT01369069.
Tissue-specific DNA methylation profiles in newborns
Authors: Herzog Emilie , Galvez Jubby , Roks Anton , Stolk Lisette , Verbiest Michael , Eilers Paul , Cornelissen Jan , Steegers Eric , Steegers-Theunissen Régine 
Published: May 2013

Abstract

Background
Epidemiological studies demonstrate that foetal growth restriction and low birth weight affect long-term health. Derangements in tissue-specific epigenetic programming of foetal and placental tissues are a suggested underlying mechanism of which DNA methylation is best understood. DNA methylation has been mostly investigated in DNA from white blood cells. To improve baseline understanding of tissue-specific DNA methylation, we examined variation in DNA methylation profiles of the imprinted foetal growth genes IGF2 and H19 in three different tissues from the same newborn obtained at the same time.

Findings
We obtained DNA from umbilical cord blood mononuclear cells (MNC; CD34+ and CD34–, n = 6), foetal side of the placenta (n = 5) and umbilical cord Wharton jelly (n = 5). DNA methylation of the IGF2 differentially methylated region (DMR) and H19 DMR was measured using quantitative mass spectrometry. Analysis of variance testing showed no statistical difference between total mean methylation of CD34+ and CD34– MNC. Further comparisons were made with the pooled total MNC fraction. Mean IGF2 DMR methylation of Wharton jelly was 1.3 times higher (P = 0.001) than mean methylation of the pooled MNC. Placental mean methylation was 0.8 times lower (P <0.001) and Wharton jelly 0.9 times lower (P <0.001) than the pooled MNC of H19 DMR.

Conclusion
The total MNC fraction is a rather homogeneous cell population for methylation studies of imprinted genes in umbilical cord blood white blood cells, but may not always reflect the methylation levels of IGF2 and H19 in other organs.
Are interventions to reduce the impact of arsenic contamination of groundwater on human health in developing countries effective? A systematic review
Authors: Jones-Hughes Tracey , Peters Jaime , Whear Rebecca , Cooper Chris , Evans Hywel , Depledge Michael , Pearson Mark 
Published: May 2013

Abstract
Background
Within developing countries, groundwater provides an alternative drinking source to polluted surface water. However, the presence of arsenic in some groundwater sources has resulted in chronic worldwide poisoning. The aim of this review was to determine the effectiveness of field-based technologies for the removal of arsenic from groundwater in developing countries.

Methods
A structured search strategy was conducted in a range of databases. Titles, abstracts and full texts were screened using pre-defined inclusion criteria. Included studies were quality appraised prior to data extraction. The primary outcome was the percentage of effluent water samples meeting WHO guidelines for arsenic concentrations (≤0.01 mg/L). Secondary outcomes included: (a) arsenic concentrations in effluent water samples meeting the national guideline limit (≤0.05 mg/L), (b) arsenic concentrations in human tissue, and (c) knowledge and attitudes related to the interventions.

Results
Fifty-one reports, evaluating 50 different technologies, were included. Sixty-seven percent (n = 34) of studies were conducted in Bangladesh. Fifty of the included reports were appraised as ‘weak’, with one ‘strong’ report of a randomised-controlled trial.
In summary, the effectiveness of the oxidation and filtration interventions is poor, while the evidence for coagulation, co-precipitation and filtration, subterranean and membrane and electrolytic methods is mixed. Evidence regarding adsorption and zero valent iron interventions is more persuasive with most results suggesting good evidence of effectiveness (i.e. ≥95% of samples with arsenic concentrations ≤0.01 mg/L). In particular, activated alumina and sono/three-kolshi/gagri/pitcher filters have ≥95% of samples meeting national guidelines. Disappointingly, only one study reports excellent evidence of effectiveness: BRAC (2000) for activated alumina (i.e. ≥95% of samples with arsenic concentrations ≤0.01 mg/L).
The success of each technology was highly dependent on context, especially their acceptability to users, a sense of ownership and expectations of women’s roles in society.

Conclusions
Most studies were poorly conducted and reported. Consequently, although some technologies met national guidelines, the evidence-base for decision-making regarding arsenic mitigation technologies at household- and community-level is weak. To improve this situation, primary research needs to be commissioned with adequate sample sizes, testing the impact of key contextual factors, using valid tools for analysis, and meeting standards for completeness of reporting.
Content of the mechanism of management of sustainable socioeconomic development of the region
Authors: Сорокина  , Sorokina Natalia 
Published: May 2013

In the article justified content of the mechanism of management of sustainable socio-economic development of the region, under which invited to understand the totality of the management, trust and providing subsystems, as well as ties between them and controlled subsystem. This approach has allowed the determination of the functions of the management of sustainable development of the region, describe the methods of management and to formulate the
principles of management of development of the region in order to ensure a high standard of quality of life of the population.
Correlation Between Quantum Conductance and Atomic Arrangement of Silver Atomic-Size Nanocontacts
Authors: Autreto Pedro A. , Lagos Maureen J. , Ugarte Daniel , Galvao Douglas S. 
Published: May 2013

ABSTRACTIn this work we have studied the importance of thermal effects on the structural and transport properties of Ag atomic-size nanowires (NWs) generated by mechanical stretching. Our study involve time-resolved atomic high resolution transmission electron microscopy imaging and quantum conductance measurement using an ultra-high-vacuum mechanically controllable break junction combined with quantum transport calculations. We have observed drastic changes in conductance and structural properties of Ag NWs generated at different temperatures (150 and 300 K). By combining electron microscopy images, electronic transport measurements and theoretical modeling, we have been able to establish a consistent correlation between the conductance and structural properties of Ag NWs. In particular, our study has revealed the formation of metastable rectangular rod-like Ag wires along the [001] crystallographic direction.
Interfacing Ag Nanoparticles with 1D Semiconductor Micro/Nanostructures via Joule Heating for Transfer Printing Nanodevices at Room Ambient
Authors: Logeeswaran VJ , Katzenmeyer Aaron M. , Triplett Mark , Ombaba Matthew , Islam M. Saif 
Published: May 2013

ABSTRACTWe describe an experiment to interface and characterize silver nanoparticle (AgNPs) aggregates that are self-assembled and plastically deformable on a thin gold (Au) film deposited on glass substrate. The electrical characterization is done using an electrical nanoprobe attached to a nano-manipulator inside a scanning electron microscope (SEM). Electrical current-voltage (I-V) measurements are made between the electrical nanoprobe in contact with the nanoparticle and the Au film. The Ag nanoparticles have diameters ranging between ~200-800nm and are self-assembled on a thiolated 100nm Au film. Application of a contact force via the nanoprobe even after substantial particle deformation reveals initially a small non-linear current. Upon current annealing through Joule heating, significant improvement in the electrical contact at the AgNP/substrate interface was observed. This is most likely based on bonding of the AgNPs to the Au film after passage of a high current. The need for such an annealing/sintering step will be critical in forming good ohmic contacts at ambient conditions during transfer printing of semiconductor micro/nanopillars.
Fabrication of Patterned Carbon Nanotube Field Emission Surfaces on SiC Substrates
Authors: Pochet Michael , Campbell Jonathon , Coutu Ronald , Fairchild Steven , Boeckl John 
Published: May 2013

ABSTRACTThis work focuses on the patterning of SiC substrates prior to carbon nanotube (CNT) formation using the surface decomposition growth method for the purpose of improving the field emission capabilities of the resultant CNT film. The thermal decomposition of silicon carbide (SiC) substrates is an established approach to create highly dense arrays of vertically aligned CNTs. The attractiveness of this growth approach is that the CNTs form without the aid of a catalyst metal, yielding potentially defect free CNTs ideal for various applications. Due to the high temperature anneals (1400-1700oC) and moderate vacuum conditions (10−2 – 10−5 Torr) necessary for the thermal decomposition process to initiate on the SiC substrate, patterning CNT outcroppings ideal for enhancing the surface’s field emission properties is more difficult when compared to metal catalyst based chemical vapor deposition growth processes on silicon substrates. The intent of the SiC patterning is to reduce field screening effects between neighboring emission sites during field emission while maintaining a high emission site density. Specifically, the SiC substrate is etched to form μm scale pillars on the SiC surface. Experimental findings show that SiC substrates patterned with μm scale pillars can be decomposed to form CNT topped field emission sites, yielding a field emission substrate that outperforms a non-patterned SiC/CNT film. A turn-on electric field of 4.0 V/μm was measured.
Electrical Resistivity and Magnetoresistance of the δ-FeZn10 Complex Intermetallic Phase
Authors: Koželj P. , Jazbec S. , Dolinšek J. 
Published: May 2013

ABSTRACTThe δ-FeZn10 phase possesses high structural complexity typical of complex metallic alloys: a giant unit cell comprising 556 atoms, polyhedral atomic order with icosahedrally-coordinated environments, fractionally occupied lattice sites and statistically disordered atomic clusters that introduce intrinsic disorder into the structure. The electrical resistivity is large and exhibits a maximum at about 220 K. The magnetoresistance is sizeable, amounting to 1.5 % at 2 K in 9 T field. The temperature–dependent resistivity is discussed within the frame of the theory of slow charge carriers, applicable to metallic systems with weak dispersion of the electronic bands, where the electron motion changes from ballistic to diffusive upon heating. A comparison to the theory of weak localization is also made.
Energetics of Protonic Species in Yttrium-doped Barium Zirconate: A Density Functional Theory Study
Authors: Malagoli Massimo , Liu M.L. , Park Hyeon Cheol , Bongiorno Angelo 
Published: May 2013

ABSTRACTDensity functional theory calculations are used to study the equilibrium energetics of protons on the surface and in the bulk of Y-doped BaZrO3. It is shown that protonic species in direct contact with Y dopants have energies lower than in perfect BaZrO3 by up to 0.4 eV. This energetic stabilization is achieved when the protonic species is in direct contact with two Y dopants. On the (001) surface of BaZrO3, protonic species are found to be energetically more stable than in the bulk by 1.1 eV and 1.6 eV on the BaO and ZrO2 surface terminations, respectively. At these terminations, the energy of protons recover the bulk value after penetrating three surface layers, and the energy cost associated with bulk incorporation is larger than 1 eV.
Nano-structured Aluminum Powders with Modified Protective Surface Layers
Authors: Zhang Shasha , Schoenitz Mirko , Dreizin Edward L. 
Published: May 2013

ABSTRACTThe advantage of aluminum powder as a fuel additive in energetic formulation includes its high volumetric combustion enthalpy and relatively low cost. However, the thermodynamically predicted benefits of aluminum combustion are rarely achieved because of extended ignition delays associated with heterogeneous reactions occurring at the alumina surface which surrounds the aluminum particle. In order to fully exploit aluminum’s high reaction energy, this effort focuses on adjusting its combustion dynamics by modifying its surface and structure. The modification is achieved by cryo-milling aluminum with cyclooctane, which is liquid at room temperature, but solid when cooled by liquid nitrogen. The prepared materials consist of micron-sized, equiaxial, mostly Al particles with a small amount of cyclooctane. Aluminum surface in the prepared sample is coated with a cyclooctane-modified layer with properties significantly different from those of regular alumina. Its oxidation kinetics, as observed from thermo-analytical measurements, is different from that of pure aluminum. The powder ignites at substantially reduced temperatures, produces shorter ignition delays, and higher aerosol burn rates compared to a regular spherical Al powder with similar particle sizes.
Oxidation Dynamics of Aluminum Nanorods
Authors: Li Ying , Nakano Aiichiro , Kalia Rajiv K. , Vashishta Priya 
Published: May 2013

ABSTRACTUnderstanding of combustion of metastable intermolecular composites, including the burning of aluminum nanoparticles, is critical for broad applications such as propulsion, explosives and other pyrotechnics. Aluminum nanorods (Al-NR) with oxidized shells are good candidates for stable fuel-oxidizer combinations. We investigate the oxidation dynamics of Al-NRs of different diameters (26, 36 and 46 nm) but the same aspect ratio using molecular dynamics simulations. We heat one end of the Al-NR to 1100 K and then study the oxidation reaction at the interface of the alumina shell and the Al core. We find: (1) heat produced by oxidation causes the melting of nanorods; (2) heat release is accelerated due to Al-O reaction at outside-shell and core-shell interfaces; and (3) the larger surface-to-volume ratio causes faster burning of thinner nanorods. We present results for the oxidation speed of nanorods.
Heteroepitaxial growth of C60 on tetracene single crystal
Authors: Miyadera Tetsuhiko , Mitsuta Hiroki , Ohashi Noboru , Taima Tetsuya , Zhou Ying , Yamanari Toshihiro , Yoshida Yuji 
Published: May 2013

ABSTRACTWe have developed a method for epitaxial growth of C60 thin films on tetracene single crystals. The crystal orientation of the C60 film was examined by reflection high energy electron diffraction (RHEED) and X-ray diffraction (XRD). In-situ observation by RHEED revealed that the C60 crystallizes from the very initial stage of the deposition (0.1 nm). A 6-fold symmetric pattern, which was observed in a XRD polar scan, can be taken as direct evidence for the epitaxial growth of C60 commensurate with the tetracene (001) surface lattice.
Preparation, ignition, and combustion of mechanically alloyed Al-Mg powders with customized particle sizes
Authors: Aly Yasmine , Hoffman Vern K. , Schoenitz Mirko , Dreizin Edward L. 
Published: May 2013

ABSTRACTAdding aluminum to propellants, pyrotechnics, and explosives is a common way to boost their energy density. A number of approaches have been investigated that shorten aluminum ignition delay, increase combustion rate, and decrease the tendency of aluminum droplets to agglomerate. Previous work showed that particles of mechanically alloyed Al-Mg powders burn faster than similarly sized particles of pure aluminum. However, preparation of mechanically alloyed powders with particle sizes matching those of fine aluminum used in energetic formulations was not achieved. This work is focused on preparation of mechanically alloyed, composite Al-Mg powders in which both internal structures and particle size distributions are adjusted. Binary powders with compositions in the range of 50 - 90 at. % Al were prepared and characterized. Milling protocol is optimized to prepare equiaxial, micron-scale particles suitable for laboratory evaluations of their oxidation, ignition, and combustion characteristics. Quantitative particle size analyses are done using low-angle laser light scattering. Electron microscopy and x-ray diffraction are used to examine particle morphology and phase makeup, respectively. Combustion of aerosolized powder clouds is studied using a constant volume explosion setup. For all materials, ignition and combustion characteristics are compared to each other and to those of pure Al. Compositions with improved performance (i.e., shorter ignition delay and faster pressurization rate) compared to pure Al are identified.
Numerical Calculations and Measurements of Energy Transduction in Electrically Exploded Ni/Al Laminates
Authors: Morris Christopher J. , Wilkins Paul R. , May Chadd M. , Piekiel Nicholas W. 
Published: May 2013

ABSTRACTThe electrical heating of Ni/Al laminate foils allows interrogation of phenomena at heating rates as high as 10^12 K/s. In the 2011 Fall MRS meeting, we reported on emission spectra from rapidly heated Ni/Al laminates resolved temporally over 350 ns, which provided qualitative evidence of rapid and exothermic vapor phase mixing of Ni and Al in these experiments which we term electrical explosions. These results were significant, because thermal diffusion processes normally limit Ni/Al reactions to much slower energy release rates, potentially limiting their applications. Here we present further evidence of exothermic Ni/Al mixing, quantified by experimental velocity measurements of encapsulation material and interpreted by numerical calculations of energy partitioning into different processes. These calculations agreed well with experiments from different Al, Cu, and Ni samples, sputter-deposited and lithographically patterned into bow-tie bridge structures. Velocity measurements of up to 5 km/s for 11.5 μm thick parylene encapsulation layers were accurately predicted using a single, empirical fitting parameter which depended on the electrical circuit used. The calculations also agreed with encapsulation layers accelerated by electrically exploded Ni/Al laminates as long as an additional 1.2 kJ/g of energy was included in the model. This value is precisely the enthalpy of mixing between Ni and Al, and therefore quantifies the transduction of energy into encapsulation layer kinetic energy.
Predictors of Long-Term Opioid Treatment Among Patients Who Receive Chemoradiation for Head and Neck Cancer
Authors: Kwon Jung Hye , Hui David , Chisholm Gary , Bruera Eduardo 
Published: May 2013

Abstract

Introduction.
The factors associated with successful opioid discontinuation after cancer treatment are not well-known. We determined the proportion of patients with advanced head and neck cancer who continued using opioids 3 months after the completion of radiation therapy with or without chemotherapy.

Methods.
We included 70 patients with head and neck cancer referred to our institution's supportive care center between January 1, 2008, and December 31, 2010. Patients who no longer used opioids 3 months after the completion of radiation therapy were classified as stoppers; patients who continued using opioids were considered nonstoppers. We compared demographics, cancer-related characteristics, alcoholism, substance abuse history, use of psychoactive drugs, and opioid-related factors between stoppers and nonstoppers.

Results.
In all, 44 of 70 patients (63%) and 23 of 70 patients (33%) continued opioids 3 months and 6 months after the completion of radiation therapy, respectively. A total of 18 of 44 nonstoppers (41%) and 3 of 26 stoppers (12%) were positive for alcoholism based on the CAGE questionnaire (i.e., Cut down, Annoying, Guilty, Eye opener; odds ratio: 5.3). Demographic and clinical characteristics did not differ between stoppers and nonstoppers. The median duration of any type of opioid use of CAGE-positive patients was significantly longer than that of CAGE-negative patients (median: 261 days vs. 93 days; hazard ratio: 2.5).

Conclusion.
CAGE positivity is a risk factor for opioid use beyond 3 months after the completion of radiation therapy and for duration of opioid treatment. Routine CAGE screening and meticulous follow-up are needed for these patients.