bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Copper Loading on Iron Carbide Formation and Surface Species in Iron‐Based Fischer–Tropsch Synthesis Catalysts
Authors: Peña Diego , Jensen Lise , Cognigni Andrea , Myrstad Rune , Neumayer Thomas , van Beek Wouter , Rønning Magnus 
Published: December 2017

AbstractThe effect of copper as promoter on iron carbide formation and the nature of surface species on iron‐based catalyst during Fischer–Tropsch synthesis (FTS) was investigated. Iron‐based catalysts (15 wt % of Fe) supported on alumina promoted with copper (0, 0.6, 2, and 5 wt %) were characterised in situ at relevant FTS conditions. The catalysts promoted with 2 and 5 wt % of Cu showed higher catalytic activity due to the formation of Hägg carbide (Fe5C2) detected by in situ XANES and XRD. The carbide formation is attributed to a weakening of the iron–alumina mixed‐compound interactions, and hence increasing iron reducibility and dispersion. The in situ XANES measurements indicated a maximum carburization degree (ca. 20–22 %) even at high Cu loading. The catalyst promoted with 5 wt % of Cu exhibited higher water‐gas shift activity. Aliphatic hydrocarbons, formate, and carboxylate species were detected on the catalyst surface during FTS. After exposing the spent catalysts to hydrogenation conditions, the carboxylate species remained strongly adsorbed while aliphatic hydrocarbons and formate species disappeared. The accumulation of oxygenates species on the catalyst surface increased with Cu loading. The interaction of oxygenates with alumina and iron oxide particles (FexOy) were revealed, with the latter being a possible reason for inhibition of further iron carburization.
Crystal Structures and Phase Behavior of Sulfadiazine and a Method for the Preparation of Aggregates with Good Performance
Authors: Wu Songgu , Du Shichao , Chen Mingyang , Li Kangli , Jia Lina , Zhang Dejiang , Macaringue Estevao G. J. , Hou Baohong , Gong Junbo 
Published: December 2017

AbstractThe solvate and the solvent‐free form of sulfadiazine (SD) were investigated. SD was found to exist in one solvent‐free form and the N‐methylpyrrolidone (NMP) solvate form. The NMP solvate was shown to be a channel‐type compound. The intrinsic properties of the solvents were used to evaluate the effects of solubility on the phase transformation of SD and the NMP solvate. The SD phase could transform to the NMP solvate by NMP‐mediated phase transformation, which was governed by crystallization of the NMP solvate. The crystalline NMP solvate could transform to the solvent‐free solid state through solid‐solid transformation upon heating or water penetration‐mediated phase transformation. The rate of this water penetration‐mediated phase transformation of the NMP solvate to SD was unusually fast. It can be used to obtain SD aggregates of well‐defined shape and good powder properties.
An improved plant‐wide fault detection scheme based on PCA and adaptive threshold for reliable process monitoring: Application on the new revised model of Tennessee Eastman process
Authors: Bakdi Azzeddine , Kouadri Abdelmalek 
Published: December 2017

AbstractAn improved process monitoring scheme is presented in this paper, it is based on the integration of multivariate and univariate statistical analysis methods. Instead of conventional fixed control limits, adaptive thresholds are developed for common fault detection indices used with principal component analysis, including the Hotelling T2 statistic and the sum of squared prediction error known as the Q statistic. The thresholds are updated based on a modified exponentially weighted moving average chart with a limited window length. The primary goal of this strategy is to enhance the performance of principal component analysis–based process monitoring method and overcome its shortcomings, by increasing fault detection rate to improve monitoring sensitivity and eliminating false alarms to ensure higher robustness and reliability. Fault detection in the revised model of Tennessee Eastman process benchmark is also investigated. The developed monitoring scheme is tested and compared with conventional fixed threshold technique, and its performance is evaluated across various types of process faults. The obtained results demonstrate the promising capabilities of the developed scheme.
Preparation of a Si/SiO2–Ordered‐Mesoporous‐Carbon Nanocomposite as an Anode for High‐Performance Lithium‐Ion and Sodium‐Ion Batteries
Authors: Zeng Lingxing , Liu Renpin , Han Lei , Luo Fenqiang , Chen Xi , Wang Jianbiao , Qian Qingrong , Chen Qinghua , Wei Mingdeng 
Published: December 2017

AbstractIn this work, an Si/SiO2–ordered‐mesoporous carbon (Si/SiO2–OMC) nanocomposite was initially fabricated through a magnesiothermic reduction strategy by using a two‐dimensional bicontinuous mesochannel of SiO2–OMC as a precursor, combined with an NaOH etching process, in which crystal Si/amorphous SiO2 nanoparticles were encapsulated into the OMC matrix. Not only can such unique porous crystal Si/amorphous SiO2 nanoparticles uniformly dispersed in the OMC matrix mitigate the volume change of active materials during the cycling process, but they can also improve electrical conductivity of Si/SiO2 and facilitate the Li+/Na+ diffusion. When applied as an anode for lithium‐ion batteries (LIBs), the Si/SiO2–OMC composite displayed superior reversible capacity (958 mA h g−1 at 0.2 A g−1 after 100 cycles) and good cycling life (retaining a capacity of 459 mA h g−1 at 2 A g−1 after 1000 cycles). For sodium‐ion batteries (SIBs), the composite maintained a high capacity of 423 mA h g−1 after 100 cycles at 0.05 A g−1 and an extremely stable reversible capacity of 190 mA h g−1 was retained even after 500 cycles at 1 A g−1. This performance is one of the best long‐term cycling properties of Si‐based SIB anode materials. The Si/SiO2–OMC composites exhibited great potential as an alternative material for both lithium‐ and sodium‐ion battery anodes.
Cobalt‐Catalyzed Enantioselective Negishi Cross‐Coupling of Racemic α‐Bromo Esters with Arylzincs
Authors: Liu Feipeng , Zhong Jiangchun , Zhou Yun , Gao Zidong , Walsh Patrick J. , Wang Xueyang , Ma Sijie , Hou Shicong , Liu Shangzhong , Wang Minan , Wang Min , Bian Qinghua 
Published: December 2017

AbstractThe first cobalt‐catalyzed enantioselective Negishi cross‐coupling reaction, and the first arylation of α‐halo esters with arylzinc halides, are disclosed. Employing a cobalt‐bisoxazoline catalyst, various α‐arylalkanoic esters were synthesized in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield). A diverse range of functional groups, including ether, halide, thioether, silyl, amine, ester, acetal, amide, olefin and heteroaromatics is tolerated by this method. This method was suitable for gram‐scale reactions, enabling the synthesis of (R)‐xanthorrhizol with high enantiopurity. Radical clock experiments support the intermediacy of radicals.
Selective Electrogenerative Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandialdehyde
Authors: Cao Tao , Wu Mengjia , Ordomsky Vitaly V. , Xin Xi , Wang Hao , Métivier Pascal , Pera‐Titus Marc 
Published: December 2017

Abstract2,5‐furandialdehyde (DFF) was synthesized by electrogenerative oxidation of 5‐hydroxymethylfurfural (HMF) over a PtRu catalyst with 89 % selectivity at 50 °C after 17 h. This approach opens an avenue for a selective, energy‐efficient and green oxidation of biomass‐derived platform alcohols to added‐value chemicals.
Design, modeling, and analysis of online combinatorial double auction for mobile cloud computing markets
Authors: Zhang Yuchao , Xu Ke , Shi Xuelin , Wang Haiyang , Liu Jiangchuan , Wang Yong 
Published: December 2017

SummaryWith the burgeoning of cloud service companies, cloud computing is becoming an efficient means of providing computing resources. Amazon EC2, Rackspace, Google App, and Microsoft Azure are attracting more and more users over the Internet these years. However, in mobile cloud computing (MCC), traditional cloud pricing models can no longer support the above popular applications, because user behaviors are dynamic and time sensitive. As an MCC application is the combination of communication services (eg, wireless access services) and computation services (eg, cloud services), it lacks new auctions for capturing the feature of MCC markets based on the communication and computation cooperation (3C).In this paper, we design an efficient double‐sided combinatorial auction model in the context of 3C‐based MCC to mitigate this problem. We first propose the framework of online combinatorial double auctions to model mobile cloud computing market. On this base, we give four principles of design requirements, which can make the scheme more efficient and practical, and then we design a new winner determination algorithm that shows how the auction mechanism decides commodity allocation and transaction prices. At last, we conduct a series of experiments to deep analyze the property of our mechanism. The experiment results indicate that the proposed online auction mechanism obtains comparable allocation efficiency to the social optimal solution.
Physiological stress responses to natural variation in predation risk: evidence from white sharks and seals
Authors: Hammerschlag Neil , Meÿer Michael , Seakamela Simon Mduduzi , Kirkman Steve , Fallows Chris , Creel Scott 
Published: December 2017

AbstractPredators can impact ecosystems through consumptive or risk effects on prey. Physiologically, risk effects can be mediated by energetic mechanisms or stress responses. The predation‐stress hypothesis predicts that risk induces stress in prey, which can affect survival and reproduction. However, empirical support for this hypothesis is both mixed and limited, and the conditions that cause predation risk to induce stress responses in some cases, but not others, remain unclear. Unusually clear‐cut variation in exposure of Cape fur seals (Arctocephalus pusillus pusillus) to predation risk from white sharks (Carcharodon carcharias) in the waters of Southwestern Africa provides an opportunity to test the predation‐stress hypothesis in the wild. Here, we measured fecal glucocorticoid concentrations (fGCM) from Cape fur seals at six discrete islands colonies exposed to spatiotemporal variation in predation risk from white sharks over a period of three years. We found highly elevated fGCM concentrations in seals at colonies exposed to high levels of unpredictable and relatively uncontrollable risk of shark attack, but not at colonies where seals were either not exposed to shark predation or could proactively mitigate their risk through antipredatory behavior. Differences in measured fGCM levels were consistent with patterns of risk at the site and seasonal level, for both seal adults and juveniles. Seal fGCM levels were not correlated with colony population size, density, and geographic location. Investigation at a high risk site (False Bay) also revealed strong correlations between fGCM levels and temporal variation in shark attack rates, but not with shark relative abundance. Our results suggest that predation risk will induce a stress response when risk cannot be predicted and/or proactively mitigated by behavioral responses.
A role for methanogens and methane in the regulation of GLP‐1
Authors: Laverdure Rose , Mezouari Ania , Carson Michael A. , Basiliko Nathan , Gagnon Jeffrey 
Published: December 2017

SummaryIntroductionThe gastrointestinal (GI) microbiome has emerged as a potential regulator of metabolism. However, the precise mechanisms of how microorganisms may influence physiology remain largely unknown. Interestingly, GI microorganisms, including methanogens, are localized within the same regions as the glucagon‐like peptide‐1 (GLP‐1) secreting L cells. GLP‐1 plays key roles appetite and glucose regulation. Furthermore, both methane and GLP‐1 levels are altered in obese humans with metabolic disease. We predict that high‐fat diet‐induced obesity alters the abundance of GI methanogens and that methane may play a role in the GLP‐1 secretory response from the L cell.MethodsTo demonstrate this, GLP‐1 secretion response and faecal methanogens were examined in mice given a high‐fat diet for 14 weeks. In addition, the direct effect of methane on GLP‐1 secretion was assessed in two L‐cell models (NCI‐H716 and GLUTag).ResultsHigh‐fat diet caused a significant increase in both GLP‐1 secretion and faecal methanogen content. There was a direct correlation between GLP‐1 secretion response and faecal methanogen levels. In L cells, methane stimulated GLP‐1 secretion and enhanced intracellular cAMP content.ConclusionThese results indicate that alterations in the methanogen communities occurring in obesity may play a vital role in directly enhancing GLP‐1 secretion, and that methane can directly stimulate the secretion of GLP‐1.
The Grautschenhof contract – Construction of an intermediate access under complex local conditions
Authors: Klais Frank , Wolf Petra , Lienhart Werner 
Published: December 2017

AbstractWith the start of construction on the third tunnelling contract, work has now started on all sections of the Semmering Base Tunnel. The Tunnel Grautschenhof contract is a challenging construction project with numerous unusual problems. Complex ground conditions make extensive grouting necessary. Numerous constraints above‐ground, like high‐pressure gas pipelines require monitoring and protection measures. Since the start in May 2016, two shafts, the first of three caverns and the first metres of the running tunnels have already been driven. In parallel to this, the works above ground to create two site facilities areas are now largely complete.
Community‐driven demand creation for the use of routine viral load testing: a model to scale up routine viral load testing
Authors: Killingo Bactrin M , Taro Trisa B , Mosime Wame N 
Published: December 2017

AbstractIntroductionHIV treatment outcomes are dependent on the use of viral load measurement. Despite global and national guidelines recommending the use of routine viral load testing, these policies alone have not translated into widespread implementation or sufficiently increased access for people living with HIV (PLHIV). Civil society and communities of PLHIV recognize the need to close this gap and to enable the scale up of routine viral load testing.MethodsThe International Treatment Preparedness Coalition (ITPC) developed an approach to community‐led demand creation for the use of routine viral load testing. Using this Community Demand Creation Model, implementers follow a step‐wise process to capacitate and empower communities to address their most pressing needs. This includes utlizing a specific toolkit that includes conducting a baseline assessment, developing a treatment education toolkit, organizing mobilization workshops for knowledge building, provision of small grants to support advocacy work and conducting benchmark evaluations.Results and DiscussionThe Community Demand Creation Model to increase demand for routine viral load testing services by PLHIV has been delivered in diverse contexts including in the sub‐Saharan African, Asian, Latin American and the Caribbean regions. Between December 2015 and December 2016, ITPC trained more than 240 PLHIV activists, and disbursed US$90,000 to network partners in support of their national advocacy work. The latter efforts informed a regional, community‐driven campaign calling for domestic investment in the expeditious implementation of national viral load testing guidelines.ConclusionsHIV treatment education and community mobilization are critical components of demand creation for access to optimal HIV treatment, especially for the use of routine viral load testing. ITPC's Community Demand Creation Model offers a novel approach to achieving this goal.
Assays for estimating HIV incidence: updated global market assessment and estimated economic value
Authors: Morrison Charles S , Homan Rick , Mack Natasha , Seepolmuang Pairin , Averill Megan , Taylor Jamilah , Osborn Jennifer , Dailey Peter , Parkin Neil , Ongarello Stefano , Mastro Timothy D 
Published: December 2017

AbstractIntroductionAccurate incidence estimates are needed to characterize the HIV epidemic and guide prevention efforts. HIV Incidence assays are cost‐effective laboratory assays that provide incidence estimates from cross‐sectional surveys. We conducted a global market assessment of HIV incidence assays under three market scenarios and estimated the economic value of improved incidence assays.MethodsWe interviewed 27 stakeholders, and reviewed journal articles, working group proceedings, and manufacturers’ sales figures. We determined HIV incidence assay use in 2014, and estimated use in 2015 to 2017 and in 5 to 10‐years under three market scenarios, as well as the cost of conducting national and key population surveys using an HIV incidence assay with improved performance.ResultsGlobal 2014 HIV incidence assay use was 308,900 tests, highest in Asia and mostly for case‐ and population‐based surveillance. Estimated 2015 to 2017 use was 94,475 annually, with declines due to China and the United States discontinuing incidence assay use for domestic surveillance. Annual projected 5 to 10 year use under scenario 1 – no change in technology – was 94,475. For scenario 2 – a moderately improved incidence assay – projected annual use was 286,031. Projected annual use for scenario 3 – game‐changing technologies with an HIV incidence assay part of (a) standard confirmatory testing, and (b) standard rapid testing, were 500,000 and 180 million, respectively. As HIV incidence assay precision increases, decreased sample sizes required for incidence estimation resulted in $5 to 23 million annual reductions in survey costs and easily offset the approximately $3 million required to develop a new assay.ConclusionsImproved HIV incidence assays could substantially reduce HIV incidence estimation costs. Continued development of HIV incidence assays with improved performance is required to realize these cost benefits.
Factors associated with HIV testing among young men who have sex with men in Myanmar: a cross‐sectional study
Authors: Pham Minh D , Aung Poe Poe , Paing Aye Kyawt , Pasricha Naanki , Agius Paul A , Tun Waimar , Bajracharya Ashish , Luchters Stanley 
Published: December 2017

AbstractIntroductionIn Myanmar, men who have sex with men (MSM) experience high risk of HIV infection. However, access to HIV testing and prevention services remains a challenge among this marginalized population. The objective of this study was to estimate population prevalence and correlates of prior HIV testing among young MSM (YMSM) and informs the development of HIV testing and intervention programmes that respond to the specific needs of this population.MethodsFive hundred and eighty‐five YMSM aged 18 to 24 years were recruited using respondent‐driven sampling (RDS) in a cross‐sectional survey conducted in six townships of Myanmar. RDS‐adjusted population estimates were calculated to estimate prevalence of HIV testing; RDS‐weighted logistic regression was used to examine correlates of HIV testing in the past 6 months and in a lifetime.ResultsThere were 12 participants who reported receiving a HIV‐positive test; of those, five were tested in the past 6 months. The RDS‐weighted prevalence estimates of lifetime (any prior) HIV testing was 60.6% (95% CI: 53.3% to 66.4%) and of recent (≤ 6 months) HIV testing was 50.1% (95% CI: 44.1% to 55.5%). In multivariable analysis, sexual identity was associated with lifetime but not recent HIV testing. Lifetime and recent HIV testing were associated with having three or more male sexual partners in the past 12 months (adjusted ORs (aORs) = 2.28, 95% CIs: 1.21 to 4.32 and 2.69, 95% CI: 1.59 to 4.56), having good HIV‐related knowledge (aORs = 1.96, 95% CIs: 1.11 to 3.44 and 1.77, 95% CI: 1.08 to 2.89), reporting high HIV testing self‐efficacy (aORs = 13.5, 95% CIs: 6.0 to 30.1 and 9.81, 95% CI: 4.27 to 22.6) and having access to and use of non‐HIV health‐related services in the past 12 months (aORs = 13.2, 95% CIs: 6.85 to 25.6 and 7.15, 95% CI: 4.08 to 12.5) respectively.ConclusionsHIV testing coverage among YMSM aged 18 to 24 years old in Myanmar is still suboptimal. Integrated HIV testing and prevention services in existing health service provision systems with tailored HIV information and education programmes targeting YMSM to improve HIV‐related knowledge and self‐efficacy may help to promote regular HIV testing behaviour and contribute to sustainable control of the HIV epidemic among this marginalized population in Myanmar.
Greater retention in care among adolescents on antiretroviral treatment accessing “Teen Club” an adolescent‐centred differentiated care model compared with standard of care: a nested case–control study at a tertiary referral hospital in Malawi
Authors: MacKenzie Rachel K , van Lettow Monique , Gondwe Chrissie , Nyirongo James , Singano Victor , Banda Victor , Thaulo Edith , Beyene Teferi , Agarwal Mansi , McKenney Allyson , Hrapcak Susan , Garone Daniela , Sodhi Sumeet K , Chan Adrienne K 
Published: December 2017

AbstractIntroductionThere are numerous barriers to the care and support of adolescents living with HIV (ALHIV) that makes this population particularly vulnerable to attrition from care, poor adherence and virological failure. In 2010, a Teen Club was established in Zomba Central Hospital (ZCH), Malawi, a tertiary referral HIV clinic. Teen Club provides ALHIV on antiretroviral treatment (ART) with dedicated clinic time, sexual and reproductive health education, peer mentorship, ART refill and support for positive living and treatment adherence. The purpose of this study was to evaluate whether attending Teen Club improves retention in ART care.MethodsWe conducted a nested case–control study with stratified selection, using programmatic data from 2004 to 2015. Cases (ALHIV not retained in care) and controls (ALHIV retained in care) were matched by ART initiation age group. Patient records were reviewed retrospectively and subjects were followed starting in March 2010, the month in which Teen Club was opened. Follow‐up ended at the time patients were no longer considered retained in care or on 31 December 2015. Cases and controls were drawn from a study population of 617 ALHIV. Of those, 302 (48.9%) participated in at least two Teen Club sessions. From the study population, 135 (non‐retained) cases and 405 (retained) controls were selected.ResultsIn multivariable analyses, Teen Club exposure, age at the time of selection and year of ART initiation were independently associated with attrition. ALHIV with no Teen Club exposure were less likely to be retained than those with Teen Club exposure (adjusted odds ratio (aOR) 0.27; 95% CI 0.16, 0.45) when adjusted for sex, ART initiation age, current age, reason for ART initiation and year of ART initiation. ALHIV in the age group 15 to 19 were more likely to have attrition from care than ALHIV in the age group 10 to 14 years of age (aOR 2.14; 95% CI 1.12, 4.11).ConclusionsThis study contributes to the limited evidence evaluating the effectiveness of service delivery interventions to support ALHIV within healthcare settings. Prospective evaluation of the Teen Club package with higher methodological quality is required for programmes and governments in low‐ and middle‐income settings to prioritize interventions for ALHIV and determine their cost‐effectiveness.