bluuebunny/crossref_metadata_2025_split huggingface dataset:
Students’ characteristics, learning outcomes and needs of geometry media tools in junior high school at Padang
Authors: Mirna M , Dwina F , Khairani K 
Published: May 2020

Abstract
Many factor influence mathematics learning outcomes, such as students’ attitude, interest and motivation. The aim of this research was to describe students’ characteristics, learning outcomes and geometry media tools that was been used in Junior High School at Padang. Type of study was descriptive research with qualitative approach. Instruments were questionnaire, test, observation and interview. The result shows that students’ attitude, interest and motivation to learn are in well category.
A Simple Mathematical Model of Pollutant Transfers on Ponds with Single Water Source
Authors: Ahmad D , Tasman F , Anzira A 
Published: May 2020

Abstract
This paper discusses about a simple mathematical model of the pollutant transfer in n-ponds with three assumptions. First, the amount of pollutant come to the ponds always in constant rate, second, the volume of each pond is the same and third, the water discharge is constant. Using mass conservation rule, the models is constructed for the single water source for single ponds and multiple ponds. After getting the models, the solutions of the model can be achieved analytically. Afterward the solution of the models is investigated in several cases. Firstly, the pollutant that comes to the ponds is not zero, from the solutions the amount of pollutant in a pond is accumulated in the rate of pollutant additions. Secondly, there is no additional pollutant, in this case the amount of pollutant in the first ponds always decreases, but for the next ponds it slightly increases first until a time it start to decrease. The last case if the pond is in pure condition at first then the amount of pollutant in each pond has a linear correlation that increases from the first pond until the last pond.
Dielectric and electromagnetic interference shielding properties of carbon black nanoparticles reinforced PVA/PEG blend nanocomposite films
Authors: Rani Priyanka , Ahamed M Basheer , Deshmukh Kalim 
Published: June 2020

Abstract
Polyvinyl alcohol (PVA)/polyethylene glycol (PEG) blend nanocomposite films reinforced with various loadings of carbon black nanoparticles (CBNPs) were synthesized via a solution casting approach. The structural properties of PVA/PEG/CBNPs nanocomposites were investigated using Fourier-transform infrared (FTIR) spectroscopy, indicating the strong interaction of CBNPs with the polymer blend. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results respectively confirmed the enhanced thermal stability and the variation in the melting temperature with the addition of CBNPs in polymer blend . The dielectric measurements of nanocomposite films were carried out over a frequency range from 50 Hz–20 MHz at a varied temperature range from 40 °C–150 °C using impedance analyzer . The maximum dielectric constant for neat PVA was observed to be about 21.4 at 50 Hz and 150 °C. For PVA/PEG/CBNPs nanocomposites having higher loading of CBNPs (25 wt%) the maximum value of dielectric constant was found to be ε = 375.1 at 50 Hz, 150 °C. The dielectric properties increased with the addition of CBNPs which validates a significant control on percolation threshold attributing to the well-dispersed CBNPs in the polymer blend. The electromagnetic interference (EMI) shielding effectiveness (SE) was improved from 0.1 dB to 10.6 dB with the addition of CBNPs in the PVA/PEG blend. The improved EMI SE and dielectric performance of these nanocomposites suggest CBNPs as excellent nanofillers for the development of flexible, lightweight and low-cost material for electronic applications.
Influences of welding speed on microstructure and mechanical properties of friction stir welded Al–Mg alloy with high Mg content
Authors: Li Yingli , Yan Hongge , Chen Jihua , Xia Weijun , Su Bin , Ding Tian , Li Xinyu 
Published: June 2020

Abstract
In this work, the influences of welding speed on microstructure and mechanical properties in friction stir welding (FSW) of the hot-rolled Al-9.2Mg-0.8Mn-0.2Zr-0.15Ti alloy plates has been investigated. Microstructures and mechanical properties of the joints are characterized by electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with electron dispersive spectroscopy (EDS), hardness and tensile testing. The results show that all the joints are free of volume defects at the welding speed of 25–100 mm min−1 and the fixed rotation rate of 1000 rpm. And all the nugget zones (NZs) are characteristics of fine grains with the high angle grain boundaries (HAGBs) fraction higher than 90% at the welding speed of 25–100 mm min−1. The mean grain size in NZs and tensile properties of joints exhibit a parabolic relation with the welding speed. Furthermore, the optimal welding parameters are the welding speed of 50 mm min−1 and the rotation rate of 1000 rpm. The as-prepared joint at 50 mm min−1, featured with the smallest grain size of 3.02 μm and a uniform distribution of the fine second phase particles in NZ, exhibits the highest elongation to rupture about 45% higher than the base metal (22.2 ± 1.6%) and the highest ultimate tensile strength efficiency of 87.4%. It can be attribute to the synergetic effect of the fine-grain structure with the high HAGBs fraction and the small second phase particles with a uniform distribution.
The research on oxidation resistance ability and mechanical properties of carbon fiber reinforced phenolic resin composites
Authors: Yang Guangyuan , Wang Wen , Peng Sanwen , Huang Zhixiong 
Published: June 2020

Abstract
Carbon fiber reinforced composite (CFRP) has been widely used in a lot of areas with its distinguished properties, especially mechanical properties. However, both carbon fibers and polymer substrate cannot resist high air temperature environment, limiting the application of CFRP, such as in the aerospace fields. The paper proposes two kinds of carbon fiber with oxidation resistance coatings, which are used as reinforced components to make phenolic resin substrate composites. Weight difference method, mechanical test machine and scanning electron microscope are used to characterize the antioxidation ability, mechanical properties, and surface morphology of composites. The results show that SiC/SiO2 coated carbon fibers and SiC–ZrO2–MoSi2/Ni coated carbon fibers can increase the anti-oxidation ability without decreasing the mechanical properties of composites. The failure temperature is around 1200 °C and 1600 °C respectively.
Tough, highly stretchable and self-healing poly(acrylic acid) hydrogels reinforced by functionalized basalt fibers
Authors: Wang Hang , Guo Meiling , Wu Yuanpeng , Zhang Junyao , Xue Shishan , Yang Xi , Li Zhenyu 
Published: June 2020

Abstract
Recently, self-healing properties have lately received great attention for polymeric hydrogels which enables the hydrogels to restore their structures after damage and prolong the service life of the gels. However, commonly polymeric hydrogels generally exhibit poor mechanical and self-healing properties. Herein, hydroxyl-functionalized basalt fibers (f-BF) as reinforcement and methylene bis acrylamide as the crosslinking agent were introduced into poly(acrylic acid) (PAA) hydrogels for fabrication of mechanically robust and self-healing hydrogels. The enhanced PAA hydrogel was obtained through synergistic covalent cross-linking of PAA chains and dynamic crosslinking of hydrogen bond interactions between polymeric matrix and f-BF, which endow the resultant hydrogel excellent mechanical properties and self-healing ability. The PAA/f-BF double crosslink hydrogel exhibits high tensile strength of 108 KPa and excellent toughness of 344.23 KJ.m−3, almost ∼6 times to PAA hydrogel. The as-prepared hydrogel possesses highly stretchable of 813 %, ∼4 times to PAA hydrogel. What’s more, the as-prepared hydrogel also has enhance self-healing ability based on tensile strength reaches up to ∼85 %. The excellent performances and simple preparation should enable the development of self-healing hydrogels for potential tissue engineering and bionic robotics applications.
HiGwas: how to compute longitudinal GWAS data in population designs
Authors: Wang Zhong , Wang Nating , Wang Zilu , Jiang Libo , Wang Yaqun , Li Jiahan , Wu Rongling 
Published: June 2020

Abstract

Summary
Genome-wide association studies (GWAS), particularly designed with thousands and thousands of single-nucleotide polymorphisms (SNPs) (big p) genotyped on tens of thousands of subjects (small n), are encountered by a major challenge of p ≪ n. Although the integration of longitudinal information can significantly enhance a GWAS’s power to comprehend the genetic architecture of complex traits and diseases, an additional challenge is generated by an autocorrelative process. We have developed several statistical models for addressing these two challenges by implementing dimension reduction methods and longitudinal data analysis. To make these models computationally accessible to applied geneticists, we wrote an R package of computer software, HiGwas, designed to analyze longitudinal GWAS datasets. Functions in the package encompass single SNP analyses, significance-level adjustment, preconditioning and model selection for a high-dimensional set of SNPs. HiGwas provides the estimates of genetic parameters and the confidence intervals of these estimates. We demonstrate the features of HiGwas through real data analysis and vignette document in the package.

Availability and implementation
https://github.com/wzhy2000/higwas.

Contact
rwu@phs.psu.edu

Supplementary information
Supplementary data are available at Bioinformatics online.
Dissociated motor learning and de-adaptation in patients with functional gait disorders
Authors: Lin Denise , Castro Patricia , Edwards Amy , Sekar Akila , Edwards Mark J , Coebergh Jan , Bronstein Adolfo M , Kaski Diego 
Published: June 2020

Abstract
Walking onto a stationary platform that had been previously experienced as moving generates a locomotor after-effect—the so-called ‘broken escalator’ phenomenon. The motor responses that occur during locomotor after-effects have been mapped theoretically using a hierarchal Bayesian model of brain function that takes into account current sensory information that is weighted according to prior contextually-relevant experiences; these in turn inform automatic motor responses. Here, we use the broken escalator phenomenon to explore motor learning in patients with functional gait disorders and probe whether abnormal postural mechanisms override ascending sensory information and conscious intention, leading to maladaptive and disabling gait abnormalities. Fourteen patients with functional gait disorders and 17 healthy control subjects walked onto a stationary sled (‘Before’ condition, five trials), then onto a moving sled (‘Moving’ condition, 10 trials) and then again onto the stationary sled (‘After’ condition, five trials). Subjects were warned of the change in conditions. Kinematic gait measures (trunk displacement, step timing, gait velocity), EMG responses, and subjective measures of state anxiety/instability were recorded per trial. Patients had slower gait velocities in the Before trials (P &lt; 0.05) but were able to increase this to accommodate the moving sled, with similar learning curves to control subjects (P = 0.87). Although trunk and gait velocity locomotor after-effects were present in both groups, there was a persistence of the locomotor after-effect only in patients (P &lt; 0.05). We observed an increase in gait velocity during After trials towards normal values in the patient group. Instability and state anxiety were greater in patients than controls (P &lt; 0.05) only during explicit phases (Before/After) of the task. Mean ‘final’ gait termination EMG activity (right gastrocnemius) was greater in the patient group than controls. Despite a dysfunctional locomotor system, patients show normal adaptive learning. The process of de-adaptation, however, is prolonged in patients indicating a tendency to perpetuate learned motor programmes. The trend to normalization of gait velocity following a period of implicit motor learning has implications for gait rehabilitation potential in patients with functional gait disorders and related disorders (e.g. fear of falling).
Effectiveness of Direct-acting Antivirals for the Treatment of Chronic Hepatitis C in Rwanda: A Retrospective Study
Authors: Nsanzimana Sabin , Penkunas Michael J , Liu Carol Y , Sebuhoro Dieudonne , Ngwije Alida , Remera Eric , Umutesi Justine , Ntirenganya Cyprien , Mugeni Soline D , Serumondo Janvier 
Published: June 2020

Abstract

Background
Direct-acting antivirals (DAAs) are becoming accessible in sub-Saharan Africa. This study examined the effectiveness of DAAs in patients treated through the Rwandan national health system and identified factors associated with treatment outcomes.

Methods
This retrospective study used data from the national hepatitis C virus (HCV) program for patients who initiated DAAs between November 2015 and March 2017. Sustained virological response at 12 weeks after treatment (SVR12) was the primary outcome. Logistic regression models were fit to estimate the relationship between patients’ clinical and demographic characteristics and treatment outcome.

Results
894 patients started treatment during the study period; 590 completed treatment and had SVR12 results. Among the 304 patients without SVR12 results, 48 were lost to follow-up and 256 had no SVR12 results but clinical data indicated they likely completed treatment; these patients were classified as nonvirological failure because viral clearance could not be determined. In a per-protocol analysis of 590 patients with SVR12 results, SVR12 was achieved in 540 (92%), and virological failure occurred in 50 (8%). Pretreatment HCV RNA above the median split was associated with virological failure. Intention-to-treat analyses including all patients showed that SVR12 was achieved in 540 (60%), with nonvirological failure in 304 (34%) and virological failure in 50 (6%). Patients in Western Province were more likely to experience nonvirological failure than patients in Kigali, likely owing to the 5–7-hour travel required to access testing and treatment.

Conclusions
DAAs were effective when implemented through the Rwandan national health system. Decentralization and enhanced financing are underway in Rwanda, which could improve access to treatment and follow-up as the country prepares for HCV elimination.
Elevated Risk of Bacterial Vaginosis Among Users of the Copper Intrauterine Device: A Prospective Longitudinal Cohort Study
Authors: Peebles Kathryn , Kiweewa Flavia M , Palanee-Phillips Thesla , Chappell Catherine , Singh Devika , Bunge Katherine E , Naidoo Logashvari , Makanani Bonus , Jeenarain Nitesha , Reynolds Doerieyah , Hillier Sharon L , Brown Elizabeth R , Baeten Jared M , Balkus Jennifer E ,   MTN-020/ASPIRE study team, Baeten Jared , Palanee-Phillips Thesla , Brown Elizabeth , Soto-Torres Lydia , Schwartz Katie , Makanani Bonus , Martinson Francis , Bekker Linda-Gail , Govender Vaneshree , Siva Samantha , Gaffoor Zakir , Naidoo Logashvari , Pather Arendevi , Jeenarain Nitesha , Nair Gonasagrie , Palanee-Phillips Thesla , Matovu Flavia , Mgodi Nyaradzo , Mhlanga Felix 
Published: June 2020

Abstract

Background
Limited evidence suggests that the nonhormonal contraceptive copper intrauterine device (Cu-IUD) may increase bacterial vaginosis (BV) risk, possibly due to increased volume and duration of menses, a common side effect of Cu-IUD use. Although increases in bleeding typically resolve within 6–12 months following initiation, evaluations of the association between Cu-IUD and BV have not included more than 6 months of follow-up.

Methods
This secondary analysis of a human immunodeficiency virus type 1 prevention trial included 2585 African women ages 18–45 followed for up to 33 months. Women reported contraceptive use each month. BV was evaluated by Nugent score in 6-monthly intervals and, if clinically indicated, by Amsel criteria. Andersen-Gill proportional hazards models were used to (1) evaluate BV risk among Cu-IUD users relative to women using no/another nonhormonal contraceptive and (2) test changes in BV frequency before, while using, and following Cu-IUD discontinuation.

Results
BV frequency was highest among Cu-IUD users at 153.6 episodes per 100 person-years (95% confidence interval [CI]: 145.2, 162.4). In adjusted models, Cu-IUD users experienced 1.28-fold (95% CI: 1.12, 1.46) higher BV risk relative to women using no/another nonhormonal contraception. Compared to the 6 months prior to initiation, BV risk was 1.52-fold (95% CI: 1.16, 2.00) higher in the first 6 months of Cu-IUD use and remained elevated over 18 months of use (P &lt; .05). Among women who discontinued Cu-IUD, BV frequency was similar to pre-initiation rates within 1 year.

Conclusions
Cu-IUD users experienced elevated BV risk that persisted throughout use. Women and their providers may wish to consider BV risk when discussing contraceptive options.
Enabling Smart City With Intelligent Congestion Control Using Hops With a Hybrid Computational Approach
Authors: Abbas Sagheer , Khan Muhammad Adnan , Athar Atifa , Shan Syed Ali , Saeed Anwar , Alyas Tahir 
Published: May 2020

ABSTRACT
In a smart city, the subject of the congestion-free traffic has been leading objectives from the past decade, and many approaches are adopted to make congestion-free roads. These approaches and signals at one junction are not inter-linked with the signal at the previous one. Therefore, the traffic flow on the same road and at associative roads is not smooth. The study proposed a model with a hybrid computational approach in which the current signal incorporates the associative signals information. Simulation results have shown that the proposed approach gives more attractive results as compared to previously published approaches. It will help improve the flow of traffic and reduce traffic congestion.
Anastomotic leakage after esophagectomy for esophageal cancer: definitions, diagnostics, and treatment
Authors: Fabbi M , Hagens E R C , van Berge Henegouwen M I , Gisbertz S S 
Published: June 2020

Summary
Anastomotic leakage is one of the most severe complications after esophagectomy and is associated with increased postoperative morbidity and mortality. Several projects ranging from small retrospective studies to large collaborations have aimed to identify potential pre- and perioperative risk factors and to improve the diagnostic processes and management. Despite the increase in available literature, many aspects of anastomotic leakage are still debated, without the existence of widely accepted guidelines. The purpose of this review is to provide a cutting edge overview of the recent literature regarding the definition and classification of anastomotic leakage, risk factors, novel diagnostic modalities, and emerging therapeutic options for treatment and prevention of anastomotic leakage following esophagectomy.
Management of paraesophageal hernia review of clinical studies: timing to surgery, mesh use, fundoplication, gastropexy and other controversies
Authors: Dreifuss Nicolás H , Schlottmann Francisco , Molena Daniela 
Published: June 2020

SUMMARY
Despite paraesophageal hernias (PEH) being a common disorder, several aspects of their management remain elusive. Elective surgery in asymptomatic patients, management of acute presentation, and other technical aspects such as utilization of mesh, fundoplication or gastropexy are some of the debated issues. The aim of this study was to review the available evidence in an attempt to clarify current controversial topics. PEH repair in an asymptomatic patient may be reasonable in selected patients to avoid potential morbidity of an emergent operation. In acute presentation, gastric decompression and resuscitation could allow to improve the patient’s condition and refer the repair to a more experienced surgical team. When surgical repair is decided, laparoscopy is the optimal approach in most of the cases. Mesh should be used in selected patients such as those with large PEH or redo operations. While a fundoplication is recommended in the majority of patients to prevent postoperative reflux, a gastropexy can be used in selected cases to facilitate postoperative care.
Development and Validation of a Simple Ultrasound Activity Score for Crohn’s Disease
Authors: Sævik Fredrik , Eriksen Ragnar , Eide Geir Egil , Gilja Odd Helge , Nylund Kim 
Published: June 2020

Abstract

Background and Aims
To improve management of patients with Crohn’s disease, objective measurements of disease activity are needed. Ileocolonoscopy is the current reference standard but has limitations that restrict repeated use. Ultrasonography is potentially useful for activity monitoring, but no validated sonographic activity index is currently in widespread use. Thus, we aimed to construct and validate a simple ultrasound score for Crohn’s disease.

Methods
Forty patients were prospectively examined with ultrasound and endoscopy in the development phase. The Simple Endoscopic Score for Crohn’s Disease [SES-CD] was used as a reference standard. Seven ultrasound variables [bowel wall thickness, length, colour Doppler, stenosis, fistula, stratification and fatty wrapping] were initially included, and multiple linear regression was used to select the variables that should be included in the final score. Second, the ultrasound data from each patient were re-examined for interobserver assessment using weighted kappa and intraclass correlation. Finally, the activity index was validated in a new cohort of 124 patients.

Results
Length, fistula and stenosis were excluded. The combination of the remaining variables provided a multiple correlation coefficient of r = 0.78. Interobserver analysis revealed poor agreement for stratification and fatty wrapping and these were thus excluded. There was excellent interobserver agreement for the remaining score consisting of wall thickness and colour Doppler. In both patient cohorts, the ultrasound score correlated well with SES-CD [Development cohort: rho = 0.83, p &lt; 0.001, Validation cohort: rho = 0.78, p &lt; 0.001]. A receiver operating characteristic curve analysis revealed an area under the curve of 0.92 and 0.88 for detecting endoscopic activity and moderate endoscopic activity, respectively.

Conclusions
A simple ultrasound activity index for Crohn’s disease consisting of bowel wall thickness and colour Doppler was constructed and validated and correlated well with endoscopic disease activity.
ClinicalTrials. gov ID: NCT03481751
Challenges in Modeling Pheromone Capture by Pectinate Antennae
Authors: Jaffar-Bandjee Mourad , Krijnen Gijs , Casas Jérôme 
Published: May 2020

SynopsisInsect pectinate antennae are very complex objects and studying how they capture pheromone is a challenging mass transfer problem. A few works have already been dedicated to this issue and we review their strengths and weaknesses. In all cases, a common approach is used: the antenna is split between its macro- and microstructure. Fluid dynamics aspects are solved at the highest level of the whole antenna first, that is, the macrostructure. Then, mass transfer is estimated at the scale of a single sensillum, that is, the microstructure. Another common characteristic is the modeling of sensilla by cylinders positioned transversal to the flow. Increasing efforts in faithfully modeling the geometry of the pectinate antenna and their orientation to the air flow are required to understand the major advantageous capture properties of these complex organs. Such a model would compare pectinate antennae to cylindrical ones and may help to understand why such forms of antennae evolved so many times among Lepidoptera and other insect orders.