bluuebunny/crossref_metadata_2025 huggingface dataset:
Advance in the computational tools that support the cooperative sector in Colombia
Authors: Pacheco C A , Quintero B T , Coronel-Rojas L A
Published: May 2020

The technological evolution in the 21st century allows organizations to define flexible and integral processes and information systems that guarantee their competitiveness and sustainability. The dynamics of the cooperative sector seeks to use, merge and implement new technological components, aimed mainly at strengthening its business model. The descriptive quantitative research achieves an approach with seven cooperatives (savings and credit) of the Catatumbo Region, Colombia, through the survey technique in order to determine the adaptation of cooperatives in the global panorama of information and communication technologies. In conclusion, the managers of savings and credit cooperatives require technologies to support administrative and strategic operations, as well as contribute to the design and implementation of software to ensure quality, security and effectiveness of institutional information and services to all their stakeholders, prioritizing in contributing to closing the digital divide and social inequality.
Edge irregular reflexive labeling of some tree graphs
Authors: Hesti Agustin Ika , Utoyo Imam , Dafik  , Venkatachalam M.
Published: May 2020

Let G be a connected, simple, and undirected graph with a vertex set V(G) and an edge set E(G). Total k-labeling is a function fe
from the edge set to the first ke
natural number, and a function fv
from the vertex set to the non negative even number up to 2kv, where k = max{ke
, 2kv
}. An edge irregular reflexive k labeling of the graph G is the total k-labeling, if for every two different edges x
1
x
2 and

x
1
′

x
2
′

of

G
,

w
t
(

x
1

x
2

)
≠
w
t
(

x
1
′

x
2
′

)

, where

w
t
(

x
1

x
2

)
=

f
v

(

x
1

)
+

f
e

(

x
1

x
2

)
+

f
v

(

x
2

)

. The minimum k for graph G which has an edge irregular reflexive k-labelling is called the reflexive edge strength of the graph G, denoted by res(G). In this paper, we determined the exact value of the reflexive edge strength of family trees, namely generalized sub-divided star graph, broom graphs, and double star graph.
The local edge metric dimension of graph
Authors: Adawiyah R , Dafik  , Alfarisi R , Prihandini R M , Agustin I H , Venkatachalam M
Published: May 2020

In this paper, we introduce a new notion of graph theory study, namely a local edge metric dimension. It is a natural extension of metric dimension concept. dG
(e,v) = min{d(x,v),d(y,v)} is the distance between the vertex v and the edge xy in graph G. A non empty set

S
⊂
V

is an edge metric generator for G if for any two edges

e
1

,

e
2

∈
E

there is a vertex

k
∈
S

such that

d
G

(
k
,

e
1

≠

d
G

(
k
,

e
2

)
)

. The minimum cardinality of edge metric generator for G is called as edge metric dimension of G, denoted by dimE
(G). The local edge metric dimension of G, denoted by dimE
(G), is a local edge metric generator of G if

r
(
x
k
|
S
)
≠
r
(
y
k
|
S
)

for every pair xk,ky of adjacent edges of G. Our concern in this paper is investigating some results of local edge metric dimension on some graphs.
Twin Paired Domination number of a graph
Authors: Mahadevan G. , Suganthi M. Vimala
Published: May 2020

A new domination papramter “Twin paired domination number” is introduced in this paper. The set

S
⊆
V

is called as be twin paired dominating set, if S is a paired dominating set and

<

S
c

>

has a perfect matching. The minimum cardinality over all S is called as twin paired domination number and it is denoted by TPD(G). In this paper, we investigate this parameter for some standard, special type graphs and for some power graphs.
Hybrid fuzzy kinetic model of phosphorite pellets drying process
Authors: Bobkov V , Borisov V , Fedulov Ya
Published: May 2020

The chemical-technological process of phosphate pellets drying is investigated in the paper. The hybrid fuzzy kinetic model of phosphorite pellets drying process is proposed. The features of the proposed model are as follows: firstly, differential equations with fuzzy thermal-physical characteristics of pellets are used to estimate the thermal conductivity of pellets; secondly, a fuzzy rule-based model is used to determine the most difficult parameters to calculate. The method based on the developed hybrid model is proposed for analyzing the drying process of phosphorite pellets. The proposed method uses an original approach that allows solving the problem of increasing uncertainty of results in iterative calculations based on the modal interaction of fuzzy thermal characteristics represented by fuzzy numbers.
Modelling of disordering regions in proton-irradiated silicon
Authors: Bogatov N , Grigoryan L , Klenevsky A , Kovalenko M , Nesterenko I
Published: May 2020

A model of disordering regions generation as a result of interstitial atom-vacancy pairs separation in view of neutral and charged pair states was developed. The model allows to define the radius and the mean number of vacancies of a disordering region. Distribution profiles of interstitial silicon, vacancies, divacancies, disordering regions created by low-energy protons in silicon were calculated, as well as the disordering regions parameters dependencies on proton energies. It was shown that the disordering region distribution maximum is spatially separated from interstitial silicon, vacancies and divacancies distribution maximums. This allows to differentially modify superficial and volumetric properties of semiconductor structures.
Implementation of Modul Based on Snowball Throwing Model to Improve Interest of Exercise Working in Mathematical Learning for 4th Grade in SDN 19 Nan Sabaris
Authors: Rismaini L , Erdriani D , Dewimarni S
Published: May 2020

This research is motivated by the low interest of students in the training in mathematics learning in the fourth grade of SDN 19 Nan Sabaris, Padang Pariaman Regency. The purpose of this study was to look at the contribution of snowball throwing-based teaching materials to increase the interest in working on mathematics training for fourth grade students of SDN 19 Nan Sabaris. This type of research is descriptive, with a sample of all fourth grade students of SDN 19 Nan Sabaris registered in the 2018/2019 school year. The sampling technique used was purposive sampling because the available sample classes were limited. The instrument used was the observation sheet, and the results of the instrument analysis showed an increase in students’ interest in doing mathematics training after the use of Snowball Throwing-based teaching materials in grade IV SDN 19 Nan Sabaris.
Preliminary Reasearch Development of Mathematics Learning Device Based on Cognitive Conflict to Improve Critical Thinking Ability of 1st Grade Senior High School Students
Authors: Juwita R , Fauzan A
Published: May 2020

This research discusses about the development of mathematics learning device based on cognitive conflict to improve critical thinking skills of class X students. Learning device was developed in the form of Learning Implementation Plans (in the form of RPP) and Student Worksheets (SW). The model of development research that has been used in this study is the Plomp model (Preliminary Research, Prototyping Phase, and Assessment Phase). However, this research only reached to the preliminary research stage. The subject of this study was the 1st grade students of SMAN 3 Painan. Based on the results of interviews to several teachers of SMAN 2 Painan and SMAN 3 Painan concluded that the learning device used by teachers have not been able to stimulate students to think critically optimally.
Preliminary Research of Mathematics Learning Device Development Based on Realistic Mathematics Education (RME)
Authors: Ulfah A S , Yerizon Y , Arnawa I M
Published: May 2020

Based on the preliminary research stage conducted in Public Junior High School (SMPN) 3 Muara Bungo, it is obtained that students’ reasoning ability is low and has yet achieved optimum result. This is due to inappropriate learning device available in which it is yet facilitating the students in improving their mathematics reasoning. Therefore, it is of vital importance to develop learning devices in the form of lesson plan (RPP) and student worksheet (LKPD) based on Realistic Mathematics Education (RME). RME provides more opportunities for the students to be more active in comprehending mathematics concept, think logically, and are able to draw a problem fine conclusion. The purpose of this research is to obtain valid, practical, and effective learning device based on RME for class VII of Junior High School. Research data were collected through observation, interview, document, questionnaire, and mathematical reasoning ability. The research participants are students of class VII SMPN 3 Muaro Bungo. This is a model development research. Plomp model was employed as the development model in this research. There are 3 phases on this model, namely, preliminary research phase, development or prototyping phase, and assessment phase. However, this research focuses only on preliminary research phase. It is including things required to design the expected learning device. The result of preliminary research is 1) students’ mathematical reasoning ability has optimum yet; 2) class VII students are in their transition from elementary school to junior high school level; hence mathematics learning requires concrete learning object or mathematics learning should be linked with their daily life; 3) RPP used provides less support to improve students ability in mathematical reasoning and it provides less opportunities for the students to be more active; 4) students expected that LKPD has to be detail, attractive, fun, and easy to comprehend.
The Development Mathematics Device with Problem Based Learning Model to Increase Mathematical Problem Solving Ability
Authors: Erawati N , Permana D
Published: May 2020

The issue of students’ difficulties in Mathematical problem solving should be resolved. One of the ways to overcome that problem is developing an appropriate learning tools. This case is expected to increase students’ ability in solving Mathematical problem. The type of this research was development research and used plom model in it. This research was consisted of three stages. They were prelimenary, development, and evaluation analysis. The result of this research was practical and effecctive Mathematics learning device. The analysis validation of lesson plan and students’ worksheet stated that they were valid. Besides, learning device was practical based on the result of analysis. The result was proven at interview guidelines, teacher’s response questionnaire, students’ response questionnaire and observation sheet in implementation of learning. The result of average percentage of practical score, teacher’s response got 88.99 %. Meanwhile, students’ response was 85.12 %. The result of practicality of learning device was strongly practical categories. Besides, learning device was effective to increase the ability of students in solving problem, especially at grade one of senior high school in Indonesia. Learning device that was developed had effective criteria. The result of students’ competency who are able to solve the Mathematic problem was 63.63 %. Theirscore were above Minimum Criteria of Mastery Learning.
The validity of mathematic learning device based on learning cycle to improve reasoning abilities of junior high school’s students
Authors: Zarista R H , Asmar A , Yerizon Y
Published: May 2020

The research problem in is the students’ mathematical reasoning ability is low, it is caused by learning device designed by the teacher does not yet support how to construct student’s mathematical reasoning ability. Through the development of this learning instrument, it is expected that students’ abilities in mathematical reasoning can increase. Learning tools are developed in the form of Lesson Plan and Student’s Worksheets. We use research Plomp’s model: initial research, prototype phase, and assessment phase. The results of preliminary analysis research, mathematical reasoning ability and student learning outcomes are still low. Teachers and students need learning tools based on Learning Cycle 5E with simple language and guide students to understand mathematics well. This study produced a valid mathematics learning device.
The developed hypothetical learning trajectory for integral topic based on realistic mathematics education
Authors: Sarvita L , Syarifuddin H
Published: May 2020

This article discussed the development of hypothetical learning trajectory for integral topic which based on realistic mathematics education for class XI Senior High School (SMA). The study focused on the phase of one to one evaluation by using observation. In this phase, we try it out to three students which divided into low, medium and high mathematics ability. Based on the observation, it can be concluded that the designed Hypothetical Learning Trajectory (HLT) can guide the students to achieve the expected purpose, that is the students can construct and discover the concept of integral by themselves based on their experience. Students use their reasoning ability to solve the given real problem so that their mathematical reasoning ability is improved.
Analysis of student error in completion analytical geometry problems in circle and sphere material
Authors: Asmar A , Delyana H
Published: May 2020

The purpose of this study is to identify student errors in solving the matter of circular material and spherical analytic geometry. The subject of this research is the 2nd semester students of the Mathematics Department at Universitas Negeri Padang. The type of this research is descriptive research. The type in this study is a qualitative approach. The data collection were obtained through documentation, tests and interviews. Data analysis was carried out in a qualitative descriptive. The results showed that the learning difficulties of students in the circle and sphere materials in terms of concepts, principles, and algorithms were: (a) Inability to remember, (b) Misclassification, (c) Error strategy, (d) Error calculation, (e) Difficulties in using algorithms. Teachers’ efforts to overcome student learning difficulties, namely: (a) provide training in varied questions (b) make a personal approach to students (c) repeat the questions that have been learned (d) provide direction to students to remember the formula learned (e) guiding and directing students to use the algorithm correctly. So that the teacher needs to use the right strategies and methods in teaching mathematical concepts.
Designing hypothetical learning trajectory for learning the importance of hypothesis testing
Authors: Syafriandi S , Fauzan A , Lufri L , Armiati A
Published: May 2020

This study aims to design student learning trajectories in learning the concept of the importance of hypothesis testing in inferential statistics. This study used design research. Design research consists of three stages, i.e. (1) preparing for the experiment; (2) teaching experiment; and (3) retrospective analysis. This study focused on the first stage, because the main purpose of this research was to develop a series of learning activities to learn the importance of hypothesis testing in inferential statistics. The result of this study is an hypothetical learning trajectory (HLT) to find the concept of the importance of hypothesis testing in inferential statistics. HLT was designed using a realistic mathematics education (RME) approach. The context used in designing HLT is to tossed a coin to determine which football team will kick off. Using iceberg, a series of learning trajectories are designed so that students are able to find out by themselves that testing hypotheses is an important concept in proving the assumption that coin is used in balance.
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

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

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

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

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

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

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

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

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 < 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 < 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 < 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

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

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 < .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

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

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

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

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 < 0.001, Validation cohort: rho = 0.78, p < 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

Synopsis

Insect 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.
Every Rule Has an Exception: a Cheater in the Community-Wide Mutualism in Antarctic Seaweed Forests
Authors: Heiser Sabrina , Amsler Charles D , McClintock James B , Shilling Andrew J , Baker Bill J
Published: May 2020

Synopsis

Dense macroalgal forests on the Western Antarctic Peninsula serve important ecological roles both in terms of considerable biomass for primary production as well as in being ecosystem engineers. Their function within the Antarctic ecosystem has been described as a crucial member of a community-wide mutualism which benefits macroalgal species and dense assemblages of associated amphipod grazers. However, there is a cheater within the system that can feed on one of the most highly chemically defended macroalgal hosts. The amphipod Paradexamine fissicauda has been found to readily consume the finely branched red macroalga Plocamium cartilagineum. This amphipod grazer not only feeds on its host, but also appears to sequester its host’s chemical defenses for its own utilization. This review summarizes what we know about both of these exceptions to the community-wide mutualism.
Recommendations for Advancing Genome to Phenome Research in Non-Model Organisms
Authors: Burnett Karen G , Durica David S , Mykles Donald L , Stillman Jonathon H , Schmidt Carl
Published: May 2020

Synopsis

The 2020 SICB Society-wide Symposium “Building Bridges from Genome to Phenome: Molecules, Methods and Models” brought together a diverse group of scientists to discuss recent progress in linking phenotype plasticity to changes at the level of the genome, epigenome, and proteome, while exploring the boundaries between variation and speciation. In a follow-up workshop, participants were asked to assess strengths and weaknesses of current approaches, to identify common barriers inhibiting their progress, and to outline the resources needed to overcome those barriers. Discussion groups generally recognized the absence of any overarching theoretical framework underlying current genome to phenome research and, therefore, called for a new emphasis on the development of conceptual models as well as the interdisciplinary collaborations needed to create and test those models. Participants also recognized a critical need for new and improved molecular and bioinformatic approaches to assist in describing function/phenotypes across phylogeny. Additionally, like all scientific endeavors, progress in genome to phenome research will be enhanced by improvements in science education and communication both within and among working groups.
A Novel Laboratory Assay to Monitor Unfractionated Heparin Dosing in Patients Taking Apixaban Prior to Hospital Admission
Authors: Strickland Sydney W , Palkimas Surabhi , Acker Mary , Bazydlo Lindsay A L
Published: June 2020

Introduction

When monitoring heparin, anti-Xa assays are susceptible to interference from apixaban taken before admission and can result in inappropriate dose adjustments that can negatively affect patient care.

Methods

We derived a novel assay, termed corrected heparin (CH), using quantified values from a chromogenic anti-Xa assay with heparin calibrators before and after heparinase treatment to eliminate any interference from apixaban within the patient sample. We retrospectively assessed 469 specimens from 72 patients at our institution who had their unfractionated heparin infusion monitored using the CH assay because of known apixaban use. These patients were included in the study if they had detectable apixaban levels (>0.1 IU/mL by anti-Xa).

Results

The analytical performance of the assay was evaluated, and precision was found to be 8.8% within 1 day and 13.3% over multiple days, with acceptable linearity (R2 = 0.997). Evaluation of clinical performance was compared with the partial thromboplastin time (PTT), showing a lack of correlation similar to comparisons between the PTT and anti-Xa assay (Blood Coagul Fibrinolysis 1993;4:635–8). The mean time to a therapeutic result in this cohort was 10 hours and 10 minutes. The CH assay was used to determine how long the apixaban was detected by the anti-Xa assay. The majority of patients (80%) still had measurable anti-Xa assay interference from apixaban at 24 hours after the last apixaban dose.

Conclusions

We have developed and evaluated an assay capable of quantifying heparin in the presence of apixaban. This assay showed acceptable performance in both analytical and clinical performance.
Evaluate the Effect of Zinc Oxide and Silver Nanoparticles on Biofilm and icaA Gene Expression in Methicillin-Resistant Staphylococcus aureus Isolated From Burn Wound Infection
Authors: Shakerimoghaddam Ali , Razavi Delaramsadat , Rahvar Farzaneh , Khurshid Maria , Ostadkelayeh Shokoufeh Mogharabi , Esmaeili Seyed-Alireza , Khaledi Azad , Eshraghi Mohsen
Published: June 2020

Methicillin-resistant Staphylococcus aureus is the cause of nosocomial and community-acquired infections. This study aimed to evaluate the effect of zinc oxide and silver nanoparticles (ZnO-Ag NPs) on biofilms formation and icaA gene expression in methicillin-resistant S. aureus (MRSA). In this study, three standard strains (ATCC 43300, 25923, and 29913) and a clinical isolate are included. The minimum inhibitory concentration (MIC) of nanoparticles was determined by microdilution broth method. The antibacterial effects of ZnO-Ag NPs either alone or in combination with each other were compared with vancomycin (as the control group). The effect of MIC and sub-MIC concentrations of ZnO-Ag NPs on biofilm formation was determined by the microtiter plate method. The expression level of the icaA gene was assessed by real-time PCR LightCycler® 96 software (Version 1.1.0.1320, Roche, Germany). technique. All experiments were repeated three times. Data were analyzed using SPSS software through ANOVA and t-test. The P-value of less than .05 was considered as statistically significant. The average MICs of ZnO, Ag, and ZnO-Ag NPs compounds were 393.2, 179.8, and 60.8 μg/ml, respectively. The compound of ZnO-Ag NPs had a synergistic effect against all isolates. ZnO-Ag NPs decreased the biofilm formation rate at MIC and sub-MIC concentrations (P < .001). Sub-MIC ZnO-Ag NPs concentration significantly reduced the icaA gene expression in S. aureus strains (P < .03). The sub-MIC concentration of ZnO-Ag NPs reduced biofilm formation rate and icaA gene expression in Staphylococcus aureus strains compared with vancomycin. It can be used to cover medical devices after examining more clinical isolates to prevent bacterial colonization.
Distribution characteristics of the advance abutment pressure in a deep stope
Authors: Zhang Pingsong , Sun Binyang
Published: June 2020

The advance abutment pressure on the coal mining face of a deep stope plays a decisive role in the surrounding rock instability, rock burst and coal-gas outburst. Based on distributed optical fiber sensing technology and theoretical analysis of the stress state, the distribution characteristics of the advance abutment pressure were tested. Taking the 61103 coal mining face of a mine in Inner Mongolia as an example, downhole measurement research was carried out. Based on the monitoring data, a two-dimensional (2D) geological model for the distribution of the advance abutment pressure during the mining process was developed. To verify the validity of the model, a verification borehole was located on the 61201 coal mining face of the same mining area, the two borehole datasets were comprehensively analysed and the model was corrected. The modified model shows that the influence scope of the advance abutment pressure is 0–26.5 m, the position of the peak stress is 5.1–6.4 m in front of the coal mining face and the peak stress can reach 21.98–23.98 MPa. The stress concentration coefficient is 1.22–1.91 and the vertical influence depth is 13–14 m. Moreover, the advance abutment pressure exhibits obvious zoning in the transverse direction, and the stress at the same position in front of the coal mining face will undergo a process of steady-slow increase-significant increase-peak-decrease. The technical parameters obtained from this study can be used for other coal mining faces in the area. In addition, the testing result of the abutment pressure from the distributed optical fiber sensors is effective and can provide a new research method for mine safety monitoring.