bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal of Impurities from Metallurgical Grade Silicon by Liquation Refining Method
Authors: Li Jing-wei , Guo Zhan-cheng , Tang Hui-qing , Li Jun-cheng 
Published: April 2013

AbstractTo develop a new method of refining silicon for use in solar cell materials, liquation refining with Al-Si alloying was proposed for purification of metallurgical grade silicon (MG-Si). The morphologies of impurities, especially for phosphorus and iron, before and after purification were analyzed. By alloying MG-Si with Al, phosphorus in MG-Si formed Al-Si-Ca-P impurity phase and iron formed skeletal-shaped α-Al8SiFe2 phase into the Al-Si eutectic phase from MG-Si with the presence of Al. It can be concluded that removal mechanism of phosphorus and iron was not only a segregating process, but also a recombining process within certain elements to form specified impurity phases. By centrifugal separation, average separation ratio was 75.73% and average recovery ratio was 82.52% for Al-45%Si system, which is better than traditional separation methods and avoids considerable loss of Al and acid. After refining for four times, mass fractions of phosphorus and boron were reduced to 0.46 × 10−6 and 0.21 × 10−6 respectively. For transition metal impurities, Fe, Ti and Mn, removal fractions of those all were more than 95%.
Differential effects of religiosity on sexual initiation among Nigerian in-school adolescents
Authors: Asubiaro Olayinka Yetunde , Fatusi Adesegun Olayiwola 
Published: April 2013

Abstract
Background: Sexual initiation in adolescence has significant health implications; identifying associated risk and protective factors is critical for context-specific evidence-based interventions. This study examined the influence of religiosity on sexual debut among in-school adolescents in Lagos State, Nigeria.
Methods: Data was obtained from 1350 randomly selected in-school adolescents using a self-administered questionnaire. Internal and external religiosity, defined based on the extant literature, were the independent variables. The dependent variable was “ever had sex.” The association between religiosity and the age of sexual debut was assessed using Cox regression and controlling for relevant covariates. The hazard ratio (HR) and 95% confidence interval (CI) were calculated.
Results: Of the participants, 19.8% of the females and 26.6% of the males have had sex (p<0.004). Internal religiosity was protective against sexual debut among females (HR=0.63, 95% CI=0.44–0.91), whereas external religiosity was protective among the males (HR=0.70, 95% CI=0.51–0.71). Age was positively associated with sexual debut among both male (HR=1.11, 95% CI=1.001–1.24) and female adolescents (HR=1.26, 95% CI=1.11–1.42). Early pubertal development (HR=1.11; 95% CI=1.001–1.24) was also a risk factor for male adolescent sexual initiation. In addition, knowledge of HIV/AIDS risk (HR=0.47; 95% CI=0.30–0.72) was a protective factor against sexual debut among adolescent females, whereas the positive perspective of friends’ involvement in sex (HR=1.014; 95% CI=1.21–2.58) was a risk factor.
Conclusion: The protective effect of internal and external religiosity with regards to sexual debut varied by gender among Nigerian in-school adolescents; the gender differences as well as other significant factors should be taken into account in evidence-based programming to address adolescent sexual health challenges in Nigeria.
Determination of Kinetic Parameter in a Unified Kinetic Model for the Photodegradation of Phenol by Using Nonlinear Regression and the Genetic Algorithm
Authors: Moreira Jesus , Serrano-Rosales Benito , Valades-Pelayo Patricio J. , de Lasa Hugo 
Published: April 2013

Abstract
This study reports the kinetic parameter estimation in the photocatalytic degradation of phenol over different TiO2 catalysts by using the Genetic Algorithm (GA) and nonlinear regression. Reaction networks are based on a previously reported unified kinetic model (UKM) of the Langmuir–Hinshelwood type. Nonlinear least-squares fitting and GA are used to find the values for the kinetic constants. The computed parameters were found to predict experimental data for phenol photodegradation at different levels of concentrations. It is shown that both methods render close values for the kinetic constants. This suggests that UKM approach gives the global minimum and as a result, this method provides good and objective parameter estimates with low to moderate cross-correlation among kinetic constants and acceptable 95% Confidence Intervals (CIs). Global optimization by using GA requires extensive computer times of up to 5 minutes. Least square fitting provides the same results with computer times of seconds only. It is then concluded that the UKM approach effectively avoids overparameterization by finding the global optimum when optimizing the kinetic constants.
Synthesis and electrochemical applications of nitrogen-doped carbon nanomaterials
Authors: Majeed Saadat , Zhao Jianming , Zhang Ling , Anjum Saima , Liu Zhongyuan , Xu Guobao 
Published: April 2013

AbstractNitrogen doping is an effective way to tailor the properties of the shaped carbon materials, including the nanotubes, nanocups, nanofibers, as well as the nanorods, and render their potential use for various applications. The common bonding configurations obtained on the N insertion is the pyridinic N and pyrrolic N, which impart the characteristic properties to these carbon materials. This review will focus on the nitrogen-doped carbon materials, the doping effect on the electrochemistry of the doped nanomaterials, and the various synthetic methods to introduce N into the carbon network. The potential applications of the N-doped materials are also reviewed on the basis of the experimental and theoretical studies in electrochemistry.
Mechanical, electrical and tribological properties of graphite filled polyamide-6 composite materials
Authors: Unal Huseyin , Esmer Kadir , Mimaroglu Abdullah 
Published: April 2013

AbstractIn this study, the influence of adding graphite filler, on the mechanical, electrical and tribological properties of nylon-6 composites, is studied. Graphite fillers with different percentages, varying between 5 and 15 wt% were added to nylon-6 polymer material. Nylon-6 composite samples were prepared by the injection molding process. Tensile, impact, electrical and tribological tests were carried out and the dielectric permittivity tangent loss factor, tensile strength, modulus of elasticity, elongation at break, impact strength, specific wear rate and coefficient of friction properties were obtained. The results showed that the tensile strength, elongation at break, impact strength, and specific wear rate of nylon-6 composites, decrease with the increase in graphite filler weight ratio, while the modulus of elasticity, hardness, real part of dielectric permittivity, imaginary part of dielectric permittivity and dielectric loss, increase with increase in the filler weight ratio. Furthermore, it is observed that a rise in the relaxation time of ionic polarization is proportional to the increase in the amount of graphite in the medium and the dielectric conductivity and loss decrease proportionally after approximately 10 KHz. Finally, the maximum improvement in properties, in total, is recorded following the addition of 5 to 10 wt% graphite filler.
Wetting and the reaction of multiwalled carbon nanotube-reinforced composite solder with a copper substrate
Authors: Huang Her-Yueh , Yang Chung-Wei , Pan Sian-Ze 
Published: April 2013

Abstract
In this work, contact angle, spreading area, and isothermal aging tests were conducted to study the difference between Sn-3Ag-0.5Cu lead-free solder and its composite solder at different multiwalled carbon nanotube reinforcement volume fractions. The material interaction between the solder and the substrate at different aging temperatures and times was investigated using scanning electron microscopy elemental analysis. The experimental results indicated that the composite solder had a lower contact angle as well as good spreading area. An intermetallic compound layer was found between the solder and the copper substrate, and the thickness of this reaction layer increased with increasing aging temperature and time. Meanwhile, the intermetallic compound layer of multiwalled carbon nanotube reinforcement composite solder was thicker than that of the Sn-3Ag-0.5Cu lead-free solder. The composite solder with 0.1 vol% multiwalled carbon nanotube reinforcement addition exhibited better comprehensive properties than composite solders with other reinforcement volume fractions.
Crystal structure of di-aqua-bis-(2-(4-methyl-5-oxo-4-propan-2-yl-1Himidazol- 2-yl)pyridine-3-carboxylic acid-nickel(II), Ni(C13H14N3O3)2(H2O)2, C26H32N6NiO8
Authors: Liang Peng , Tian Wei-Man , Yin Xian-Hong , Wei Cheng-Yu , Peng Cai-Hua 
Published: April 2013

Abstract C26H32N6NiO8, orthorhombic, Pbca (no. 61), a = 12.511(3) Å, b = 19.521(5) Å, c = 23.053(6) Å, V = 5630.2 Å3, Z = 8, Rgt(F) = 0.0541, wRref(F2) = 0.1570, T = 296 K.
Crystal structure of diaqua-bis(2-(4-carboxyphenyl)acetato-κO)-bis(1,3- di(pyridin-4-yl)propane-κN)cobalt(II), C44H46CoN4O10
Authors: Li Gui-Lian , Yin Wen-Dong 
Published: April 2013

Abstract C44H46CoN4O10, monoclinic, C2/c (no. 15), a = 43.953(6) Å, b = 8.375(1) Å, c = 11.404(2) Å, β = 101.210(1)°, V = 4117.7 Å3, Z = 4, Rgt(F) = 0.0322, wRref(F2) = 0.0836, T = 296 K.
A Hypomorphic Mutation Reveals a Stringent Requirement for the ATM Checkpoint Protein in Telomere Protection During Early Cell Division in Drosophila
Authors: Morciano Patrizia , Zhang Yi , Cenci Giovanni , Rong Yikang S 
Published: April 2013

Abstract
Using Drosophila as a model system, we identified a stringent requirement for the conserved function of Ataxia Telangiectasia Mutated (ATM) in telomere protection during early embryonic development. Animals homozygous for a hypomorphic mutation in atm develop normally with minimal telomere dysfunction. However, mutant females produce inviable embryos that succumb to mitotic failure caused by covalent fusions of telomeric DNA. Interestingly, although the atm mutation encodes a premature stop codon, it must not have eliminated the production of the mutant protein, and the mutant protein retains kinase activity upon DNA damage. Moreover, although the embryonic phenotype of this mutation resembles that of hypomorphic mutations in the MRN complex, the function of MRN appears normal in the atm embryos. In contrast, there is a prominent reduction of the level of HipHop, an essential member of the Drosophila capping complex. How ATM functions in telomere protection remains poorly understood. The amenability of Drosophila embryos to molecular and biochemical investigations ensures that this newly identified mutation will facilitate future studies of ATM in telomere maintenance.
Quantitative Trait Locus and Haplotype Analyses of Wild and Crop-Mimic Traits in U.S. Weedy Rice
Authors: Mispan Muhamad S , Zhang Lihua , Feng Jiuhuan , Gu Xing-You 
Published: April 2013

Abstract
Conspecific weeds retained characteristics from wild ancestors and also developed crop mimicries for adaptation and competitiveness. This research was conducted to identify quantitative trait loci (QTL) associated with the wild and crop-mimic traits and to determine haplotype variants for QTL-rich regions in U.S. weedy rice. An F2 population from the cross between a cultivated (EM93-1) and a U.S. weedy (US1) rice line was evaluated for six wild and eight crop-mimic traits in a greenhouse to identify the QTL. A core collection of 27 U.S. weedy red rice lines and 14 AA-genome wild rice lines were determined for the haplotype variants. A total of 49 QTL were identified, with 45 collocated as clusters on 14 genomic segments. The number of haplotypes across the 14 segments was lower in the weedy (6.1 ± 2.4) than in the wild (7.5 ± 1.8) rice sample. Both samples shared ~50% haplotypes (wild-like). The EM93-1−like haplotypes accounted for a greater proportion (30 ± 26%) of the haplotypes in the weedy than in the wild (7 ± 10%) rice. Based on haplotype patterns for the 14 QTL cluster regions, 26 of the 28 red rice lines were clustered into two groups corresponding to the black-hull awned and straw-hull awnless morphological types, respectively. The QTL analysis demonstrated that conspecific weed-crop differentiation involved many genomic segments with multiple loci regulating natural variation for adaptation and competitiveness. The haplotype analysis revealed that U.S. weedy rice retained large blocks of linkage disequilibrium for the multiple loci from the wild relatives and also incorporated haplotypes from cultivars.
Estimating Variable Effective Population Sizes from Multiple Genomes: A Sequentially Markov Conditional Sampling Distribution Approach
Authors: Sheehan Sara , Harris Kelley , Song Yun S 
Published: April 2013

AbstractThroughout history, the population size of modern humans has varied considerably due to changes in environment, culture, and technology. More accurate estimates of population size changes, and when they occurred, should provide a clearer picture of human colonization history and help remove confounding effects from natural selection inference. Demography influences the pattern of genetic variation in a population, and thus genomic data of multiple individuals sampled from one or more present-day populations contain valuable information about the past demographic history. Recently, Li and Durbin developed a coalescent-based hidden Markov model, called the pairwise sequentially Markovian coalescent (PSMC), for a pair of chromosomes (or one diploid individual) to estimate past population sizes. This is an efficient, useful approach, but its accuracy in the very recent past is hampered by the fact that, because of the small sample size, only few coalescence events occur in that period. Multiple genomes from the same population contain more information about the recent past, but are also more computationally challenging to study jointly in a coalescent framework. Here, we present a new coalescent-based method that can efficiently infer population size changes from multiple genomes, providing access to a new store of information about the recent past. Our work generalizes the recently developed sequentially Markov conditional sampling distribution framework, which provides an accurate approximation of the probability of observing a newly sampled haplotype given a set of previously sampled haplotypes. Simulation results demonstrate that we can accurately reconstruct the true population histories, with a significant improvement over the PSMC in the recent past. We apply our method, called diCal, to the genomes of multiple human individuals of European and African ancestry to obtain a detailed population size change history during recent times.
Warts Transmitted in Families and Schools: A Prospective Cohort
Authors: Bruggink Sjoerd C. , Eekhof Just A.H. , Egberts Paulette F. , van Blijswijk Sophie C.E. , Assendelft Willem J.J. , Gussekloo Jacobijn 
Published: April 2013

BACKGROUND AND OBJECTIVE:Cutaneous warts are common in primary schoolchildren; however, knowledge on the routes of transmission of human papillomavirus (HPV) causing warts is scarce. This study examines the association between the degree of HPV exposure and incidence of warts in primary schoolchildren to support evidence-based recommendations on wart prevention.METHODS:In this prospective cohort study, the hands and feet of all children in grades 1 to 7 (aged 4–12 years) of 3 Dutch primary schools were inspected for the presence of warts at baseline and after 11 to 18 months of follow-up. Data on the degree of HPV exposure included information obtained from parental questionnaires: preexistent warts, warts in family, prevalence of warts at baseline in the class, and use of public places (eg, swimming pools).RESULTS:Of the 1134 eligible children, 97% participated; the response rate from parental questionnaires was 77%, and loss to follow-up was 9%. The incidence for developing warts was 29 per 100 person-years at risk (95% confidence interval [CI] 26–32). Children with a white skin type had an increased risk of developing warts (hazard ratio [HR] 2.3, 95% CI 1.3–3.9). Having family members with warts (HR 2.08, 95% CI 1.52–2.86) and wart prevalence in the class (HR 1.20 per 10% increase, 95% CI 1.03–1.41) were independent environmental risk factors.CONCLUSIONS:The degree of HPV exposure in the family and school class contributes to the development of warts in schoolchildren. Preventive recommendations should focus more on limiting HPV transmission in families and school classes, rather than in public places.
A Cough Algorithm for Chronic Cough in Children: A Multicenter, Randomized Controlled Study
Authors: Chang Anne Bernadette , Robertson Colin Francis , Paul van Asperen Peter , Glasgow Nicholas John , Masters Ian Brent , Teoh Laurel , Mellis Craig Michael , Landau Louis Isaac , Marchant Julie Maree , Morris Peter Stanley 
Published: April 2013

OBJECTIVES
The goals of this study were to: (1) determine if management according to a standardized clinical management pathway/algorithm (compared with usual treatment) improves clinical outcomes by 6 weeks; and (2) assess the reliability and validity of a standardized clinical management pathway for chronic cough in children.

METHODS:
A total of 272 children (mean ± SD age: 4.5 ± 3.7 years) were enrolled in a pragmatic, multicenter, randomized controlled trial in 5 Australian centers. Children were randomly allocated to 1 of 2 arms: (1) early review and use of cough algorithm (“early-arm”); or (2) usual care until review and use of cough algorithm (“delayed-arm”). The primary outcomes were proportion of children whose cough resolved and cough-specific quality of life scores at week 6. Secondary measures included cough duration postrandomization and the algorithm’s reliability, validity, and feasibility.

RESULTS:
Cough resolution (at week 6) was significantly more likely in the early-arm group compared with the delayed-arm group (absolute risk reduction: 24.7% [95% confidence interval: 13–35]). The difference between cough-specific quality of life scores at week 6 compared with baseline was significantly better in the early-arm group (mean difference between groups: 0.6 [95% confidence interval: 0.29–1.0]). Duration of cough postrandomization was significantly shorter in the early-arm group than in the delayed-arm group (P = .001). The cough algorithm was reliable (κ = 1 in key steps). Feasibility was demonstrated by the algorithm’s validity (93%–100%) and efficacy (99.6%). Eighty-five percent of children had etiologies easily diagnosed in primary care.

CONCLUSIONS:
Management of children with chronic cough, in accordance with a standardized algorithm, improves clinical outcomes irrespective of when it is implemented. Further testing of this standardized clinical algorithm in different settings is recommended.
Yield of Chest Radiography After Removal of Esophageal Foreign Bodies
Authors: Fisher Jeremy , Mittal Rohit , Hill Sarah , Wulkan Mark L. , Clifton Matthew S. 
Published: April 2013

OBJECTIVES:The aim of this study was to determine the benefit of routine postoperative chest radiography after removal of esophageal foreign bodies in children.METHODS:Medical records were reviewed of all patients evaluated with an esophageal foreign body at a single children’s hospital over 10 years. Operative records and imaging reports were reviewed for evidence of esophageal injury.RESULTS:Of 803 records identified, 690 were included. All underwent rigid esophagoscopy and foreign body removal. The most common items removed were coins (94%), food boluses (3%), and batteries (2%). The rate of esophageal injury was 1.3% (9 patients). No injuries were identified on chest radiographs done as routine or for concern of injury. Patients with operative findings suggestive of an esophageal injury (n = 105) were significantly more likely to have an injury (8.6% vs 0%, P = .0001). Of the 585 children who did not have physical evidence of injury, 40% (n = 235) received a routine chest radiograph. Regardless of the indication, no injuries were identified on chest films.CONCLUSIONS:We conclude that intraoperative findings during rigid esophagoscopy suggestive of an injury are predictive of esophageal perforation. Routine chest radiography is not warranted in children who do not meet this criterion. In patients with a concern for injury, we suggest that chest radiography should be deferred in favor of esophagram.
LiMn2O4 microspheres secondary structure of nanoparticles/plates as cathodes for Li-ion batteries
Authors: Sun Cheng-Yue , Zhu Yun-Guang , Zhu Tie-Jun , Xie Jian , Cao Gao-Shao , Zhao Xin-Bing , Zhang Shi-Chao 
Published: April 2013

Abstract
Thermal Budget Reduction for Back-end Compatibility and Control of Resistance Switching Mechanism (Unipolar to Bipolar) in Pr1-xCaxMnO3 (PCMO) RRAM
Authors: Panwar Neeraj , Rao Gurudatt , Chandra Raju N. Ravi , Nori Rajashree , Kumbhare Pankaj , Deshmukh Sanchit , Srinivasan V S Senthil , Venkataramani N. , Ganguly Udayan 
Published: April 2013

ABSTRACTA low thermal budget process for back-end compatible PCMO based RRAM cell is essential for 3D stacked memory. In this paper, we investigate two strategies to engineer low thermal budget processing for bipolar switching - (i) deposition engineering i.e. based on deposition temperature and oxygen partial pressure, (ii) post deposition anneal i.e. based on inert anneal of room temperature deposited PCMO film.. We demonstrate that both deposition and anneal shows a transition temperature above which bipolar switching is realized. Oxygen partial pressure is a key deposition process parameter. As oxygen partial pressure is reduced memory window increases, however beyond an optimal O2 partial pressure, unipolar switching is observed. Inert anneal is more effective in thermal budget reduction as N2/550°C/2min anneal has same memory performance as 650°C/2hour deposition process.
Photophysical behavior of ensembles of single semiconductor quantum dots
Authors: Patty Kira D. , Sadeghi S. M. 
Published: April 2013

ABSTRACTIn this contribution we explored the impact of irradiation intensity on the fluorescence of single quantum dots and ensembles of single quantum dots over time scales much greater than the blinking of the individual quantum dots. We also investigated how blinking and photo enhancement are influenced by photo-oxidation when the intensity of the irradiating laser was increased. Analysis of the emission photographs shows the presence of large time scale individual and ensemble blinking behavior. Analysis of the data indicates that photoinduced fluorescence enhancement occurs even when the inter-dot spacing of the quantum dots precludes the formation of a Coulomb blockade. Additionally, irradiation of ensembles of CdSe/ZnS SQDs at higher source intensities lead to a more accelerated suppression of quantum dots emission via photo-oxidation than for ensembles of closely packed quantum dots.