bluuebunny/crossref_metadata_2025 huggingface dataset:
The Danish HIV Birth Cohort (DHBC) - a nationwide, prospective cohort
Authors: Weis Nina , Katzenstein Terese L , Ørbæk Mathilde , Storgaard Merete , Pedersen Gitte , Johansen Isik S , Moseholm Ellen
Published: July 2021

Purpose

The purpose of the Danish HIV Birth Cohort (DHBC) is to investigate the significance of HIV-1 infection in pregnancy and after delivery in women living with HIV (WLWH) in Denmark and their children, in the era of antiretroviral therapy and other interventions for treatment and prophylaxis.

Participants

All WLWH giving birth to one or more children in Denmark after 31 December 1999 are included, with consecutive ongoing enrolment, if they are living with HIV and pregnant, or if they are diagnosed with HIV in relation to pregnancy, delivery or shortly after delivery.

Findings to date

DHBC has been used to describe trends in the management of pregnancies in WLWH and their outcomes on a nationwide basis, mode of delivery and predictors of emergency caesarean section as well as risk factors during pregnancy in WLWH for birth-related complications compared with women from the general population (WGP). We have found that HIV-exposed, but uninfected (HEU) children born to WLWH had a lower median birth weight and gestational age and were at higher risk of intrauterine growth retardation than children born to WGP. We have investigated risk of in-hospital admission and use of antibiotics during the first 4 years of life among HEU children and showed that HEU children had an increased risk of overall hospital admission compared with a matched control group of unexposed children.

Further, we compared anthropometric outcomes in children with a matched control group of children not exposed to HIV.

Future plans

To continuously investigate the significance of HIV infection and antiretroviral therapy in pregnancy and after delivery in WLWH in Denmark and their HEU children and compare these findings with children born to WGP.
Seroprevalence of anti-SARS-CoV-2 antibodies among school and daycare children and personnel: protocol for a cohort study in Montreal, Canada
Authors: Zinszer Kate , McKinnon Britt , Bourque Noémie , Zahreddine Monica , Charland Katia , Papenburg Jesse , Fortin Geneviève , Hamelin Marie-Ève , Saucier Adrien , Apostolatos Alex , Pierce Laura , Savard-Lamothe Ashley , Carbonneau Julie , Conrod Patricia , Haley Nancy , Laurin Isabelle , Boivin Guy , De Serres Gaston , Quach Caroline
Published: July 2021

Introduction

Further evidence is needed to understand the contribution of schools and daycares for the spread of COVID-19 in the context of diverse transmission dynamics and continually evolving public health interventions. The Enfants et COVID-19: Étude de séroprévalence (EnCORE) study will estimate the seroprevalence and seroconversion of SARS-CoV-2 among school and daycare children and personnel. In addition, the study will examine associations between seroprevalence and sociodemographic characteristics and reported COVID-19 symptoms and tests, and investigates changes in health, lifestyle and well-being outcomes.

Methods and analysis

This study includes children and personnel from 62 schools and daycares in four neighbourhoods in Montreal, Canada. All children aged 2–17 years attending one of the participating schools or daycares and their parents are invited to participate, as well as a sample of personnel members. Participants respond to brief questionnaires and provide blood samples, collected via dried blood spot, at baseline (October 2020–March 2021) and follow-up (May–June 2021). Questionnaires include sociodemographic and household characteristics, reported COVID-19 symptoms and tests, potential COVID-19 risk factors and prevention efforts and health and lifestyle information. Logistic regression using generalised estimating equations will be used to estimate seroprevalence and seroconversion, accounting for school-level clustering.

Ethics and dissemination

This study was approved by the research ethics boards of the Université de Montréal (CERSES) and the Centre Hospitalier Universitaire Sainte-Justine. Results will contribute to our knowledge about SARS-CoV-2 transmission in schools and daycares and will be made available to study participants and their families, school and public health decision-makers and the research community.
Longitudinal cohort study of injury type, settings, treatment and costs in British Columbia youth, 2003–2013
Authors: Leadbeater Bonnie , Contreras Alejandra , Rajabali Fahra , Zheng Alex , Beaulieu Emilie , Pike Ian
Published: July 2021

Background

In 2010 in British Columbia (BC), Canada, total injury costs per capita were higher among youth aged 15–24 years than in any other age group. Injury prevention efforts have targeted injuries with high mortality (transportation injuries) or morbidity (concussions). However, the profile and health costs of common youth injuries (types, locations, treatment choices and prevention strategies) and how these change from adolescence to young adulthood is not known.

Methods

Participants (n=662) were a randomly recruited cohort of BC youth, aged 12–18, in 2003. They were followed biennially across a decade (six assessments).

Results

Serious injuries (defined as serious enough to limit normal daily activities) in the last year were reported by 27%–41% of participants at each assessment. Most common injuries were sprains or strains, broken bones, cuts, punctures or animal bites, and severe bruises. Most occurred when playing a sport or from falling. Estimated total direct cost of treatment per injury was approximately $2500. In addition, 25% experienced serious injuries at three or more assessments, indicating possible differences that warrents further investigation.

Conclusions

The occurence and health cost of common injuries to youth and young adults are underestimated in this study but are nevertheless substantial. Ongoing surveillence, awareness raising, and prevention efforts may be needed to reduce these costs.
Clinicopathological significance of WT1 expression in invasive breast carcinoma with >90% mucinous component
Authors: Xu Xiaoli , Bi Rui , Shui Ruohong , Yu Baohua , Cheng Yufan , Tu Xiaoyu , Yang Wentao
Published: July 2021

Aims

This study was aimed to investigate the clinicopathological significance of immunohistochemical (IHC) Wilm’s tumour 1 (WT1) expression in invasive breast carcinoma with >90% mucinous components.

Methods

One hundred specimens of invasive breast carcinoma with >90% mucinous component were collected. All H&E-stained slides were reviewed, and the clinicopathological data, including sex, age, tumour size, nuclear grade, histological grade, growth pattern and lymph node (LN) status, were collected. IHC staining of WT1, oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and Ki-67 was performed. Fluorescence in situ hybridisation was used to verify the amplification of the HER2 gene. The relationship between WT1 expression and clinicopathological features was analysed statistically.

Results

WT1 expression was detected in 67% (67/100) of invasive breast carcinoma with >90% mucinous components. WT1 expression was significantly associated with low-to-intermediate nuclear grade/histological grade, ER and PR positivity, HER2 negativity, Ki-67 proliferation index <30% and noLN metastasis (all p<0.001). Micropapillary architecture was observed in 80% of cases. WT1 expression was not significantly correlated with different percentage of micropapillary components (p=0.422). None of the histological grade 3 tumours, tumours with HER2 overexpression/amplification and triple-negative specimens showed WT1 expression.

Conclusions

WT1 expression was significantly related with low-intermediate nuclear/histological grade, ER positivity, HER2 negativity, a lower Ki-67 proliferation index and no LN metastasis in invasive breast carcinoma with >90% mucinous component. The micropapillary growth pattern in this type of tumour did not show a specific relationship with WT1 expression.
Do people reduce compliance with COVID-19 guidelines following vaccination? A longitudinal analysis of matched UK adults
Authors: Wright Liam , Steptoe Andrew , Mak Hei Wan , Fancourt Daisy
Published: July 2021

Introduction

COVID-19 vaccines do not confer immediate immunity and vaccinated individuals may still be at risk of transmitting the virus. Governments have not exempted vaccinated individuals from behavioural measures to reduce the spread of COVID-19, such as practising social distancing. However, vaccinated individuals may have reduced compliance with these measures, given lower perceived risks.

Methods

We used monthly panel data from October 2020 to March 2021 in the UK COVID-19 Social Study to assess changes in compliance following vaccination. Compliance was measured with two items on compliance with guidelines in general and compliance with social distancing. We used matching to create comparable groups of individuals by month of vaccination (January, February or not vaccinated by February) and fixed effects regression to estimate changes in compliance over the study period.

Results

Compliance increased between October 2020 and March 2021, regardless of vaccination status or month of vaccination. There was no clear evidence that vaccinated individuals decreased compliance relative to those who were not yet vaccinated.

Conclusion

There was little evidence that sample members vaccinated in January or February reduced compliance after receiving vaccination for COVID-19. Continued monitoring is required as younger individuals receive the vaccine, lockdown restrictions are lifted and individuals receive second doses of the vaccine.
Exploiting off-target effects of estrogen deprivation to sensitize estrogen receptor negative breast cancer to immune killing
Authors: Wolfson Benjamin , Padget Michelle R , Schlom Jeffrey , Hodge James W
Published: July 2021

Background

There are highly effective treatment strategies for estrogen receptor (ER)+, progesterone receptor (PR)+, and HER2+ breast cancers; however, there are limited targeted therapeutic strategies for the 10%–15% of women who are diagnosed with triple-negative breast cancer. Here, we hypothesize that ER targeting drugs induce phenotypic changes to sensitize breast tumor cells to immune-mediated killing regardless of their ER status.

Methods

Real-time cell analysis, flow cytometry, qRT-PCR, western blotting, and multiplexed RNA profiling were performed to characterize ER+ and ER− breast cancer cells and to interrogate the phenotypic effects of ER targeting drugs. Sensitization of breast cancer cells to immune cell killing by the tamoxifen metabolite 4-hydroxytamoxifen (4-OHT) and fulvestrant was determined through in vitro health-donor natural killer cell111IN-release killing assays. A syngeneic tumor study was performed to validate these findings in vivo.

Results

Pretreatment with tamoxifen metabolite 4-OHT or fulvestrant resulted in increased natural killer (NK)–mediated cell lysis of both ER+ and ER− breast cancer cells. Through multiplexed RNA profiling analysis of 4-OHT-treated ER+ and ER− cells, we identified increased activation of apoptotic and death receptor signaling pathways and identified G protein-coupled receptor for estrogen (GPR30) engagement as a putative mechanism for immunogenic modulation. Using the specific GPR30 agonist G-1, we demonstrate that targeted activation of GPR30 signaling resulted in increased NK cell killing. Furthermore, we show that knockdown of GPR30 inhibited 4-OHT and fulvestrant mediated increases to NK cell killing, demonstrating this is dependent on GPR30 expression. Moreover, we demonstrate that this mechanism remains active in a 4-OHT-resistant MCF7 cell line, showing that even in patient populations with ER+ tumors that are resistant to the cytotoxic effects of tamoxifen, 4-OHT treatment sensitizes them to immune-mediated killing. Moreover, we find that fulvestrant pretreatment of tumor cells synergizes with the IL-15 superagonist N-803 treatment of NK cells and sensitizes tumor cells to killing by programmed death-ligand 1 (PD-L1) targeting high-affinity natural killer (t-haNK) cells. Finally, we demonstrate that the combination of fulvestrant and N-803 is effective in triple-negative breast cancer in vivo.

Conclusion

Together, these findings demonstrate a novel effect of ER targeting drugs on the interaction of ER+ and, surprisingly, ER− tumors cells with the immune system. This study is the first to demonstrate the potential use of ER targeting drugs as immunomodulatory agents in an ER agnostic manner and may inform novel immunotherapy strategies in breast cancer.
Diabetes mellitus and cardiovascular risk management in patients with rheumatoid arthritis: an international audit
Authors: Semb Anne Grete , Rollefstad Silvia , Ikdahl Eirik , Wibetoe Grunde , Sexton Joseph , Crowson Cindy , van Riel Piet , Kitas George , Graham Ian , Rantapää-Dahlqvist Solbritt , Karpouzas George Athanasios , Myasoedova Elena , Gonzalez-Gay Miguel A , Sfikakis Petros P , Tektonidou Maria G , Lazarini Argyro , Vassilopoulos Dimitrios , Kuriya Bindee , Hitchon Carol , Stoenoiu Maria Simona , Durez Patrick , Pascual-Ramos Virginia , Galarza-Delgado Dionicio Angel , Faggiano Pompilio , Misra Durga Prasanna , Borg Andrew A , Mu Rong , Mirrakhimov Erkin M , Gheta Diane , Douglas Karen , Agarwal Vikas , Myasoedova Svetlana , Krougly Lev , Valentinovna Popkova Tatiana , Tuchyňová Alena , Tomcik Michal , Vrablik Michal , Lastuvka Jiri , Horak Pavel , Medkova Helena Kaspar , Kerola Anne M
Published: July 2021

Aim

The objective was to examine the prevalence of atherosclerotic cardiovascular disease (ASCVD) and its risk factors among patients with RA with diabetes mellitus (RA-DM) and patients with RA without diabetes mellitus (RAwoDM), and to evaluate lipid and blood pressure (BP) goal attainment in RA-DM and RAwoDM in primary and secondary prevention.

Methods

The cohort was derived from the Survey of Cardiovascular Disease Risk Factors in Patients with Rheumatoid Arthritis from 53 centres/19 countries/3 continents during 2014–2019. We evaluated the prevalence of cardiovascular disease (CVD) among RA-DM and RAwoDM. The study population was divided into those with and without ASCVD, and within these groups we compared risk factors and CVD preventive treatment between RA-DM and RAwoDM.

Results

The study population comprised of 10 543 patients with RA, of whom 1381 (13%) had DM. ASCVD was present in 26.7% in RA-DM compared with 11.6% RAwoDM (p<0.001). The proportion of patients with a diagnosis of hypertension, hyperlipidaemia and use of lipid-lowering or antihypertensive agents was higher among RA-DM than RAwoDM (p<0.001 for all). The majority of patients with ASCVD did not reach the lipid goal of low-density lipoprotein cholesterol <1.8 mmol/L. The lipid goal attainment was statistically and clinically significantly higher in RA-DM compared with RAwoDM both for patients with and without ASCVD. The systolic BP target of <140 mm Hg was reached by the majority of patients, and there were no statistically nor clinically significant differences in attainment of BP targets between RA-DM and RAwoDM.

Conclusion

CVD preventive medication use and prevalence of ASCVD were higher in RA-DM than in RAwoDM, and lipid goals were also more frequently obtained in RA-DM. Lessons may be learnt from CVD prevention programmes in DM to clinically benefit patients with RA .
Low prevalence of anti-SSA (anti-Ro) and anti-SSB (anti-La) autoantibodies in female patients with rheumatoid arthritis with a wish to conceive
Authors: Smeele Hieronymus T W , Schreurs Marco W J , Costedoat-Chalumeau Nathalie , Cornette Jerome M J , Dolhain Radboud J E M
Published: July 2021

Objectives

Guidelines advise to test for anti–Sjögren's-syndrome-related antigen A (anti-SSA) and anti–Sjögren's-syndrome-related antigen B (anti-SSB) antibodies in all patients with rheumatoid arthritis (RA) who wish to conceive. Our objective was to determine the prevalence and titres of anti-SSA and anti-SSB autoantibodies in patients with RA with a wish to conceive or pregnant.

Methods

Patients were derived from two large cohorts on RA and pregnancy (PARA cohort and PreCARA cohort). In addition, to determine the clinical relevance of searching for anti-SSA and anti-SSB in patients with RA, we studied the prevalence of the maternal diagnosis of RA in the French national registry of neonatal lupus syndrome (NLS) and congenital heart block (CHB).

Results

26 out of 647 patients with RA had detectable anti-SSA and/or anti-SSB. Anti-SSA was detected in 25 out of 647 patients (3.9%) (Ro-52, n=17; Ro-60, n=19), anti-SSB in 7 out of 647 (1.1%). Thirteen women had a titre of >240 units/mL of anti-SSA antibodies. The prevalence of anti-SSA and/or anti-SSB was higher in rheumatoid factor (RF)-positive patients compared with RF-negative patients (5.1% vs 1.6%, p=0.04). No cases of CHB and/or NLS in the offspring were observed. In the French national register, the prevalence of RA in mothers with SSA related CHB was 1.5%.

Conclusion

Anti-SSA and anti-SSB have a low prevalence in patients with RA who wish to conceive. Especially for RF-negative patients, the current advise to test for anti-SSA and anti-SSB should be reconsidered.
Walnut bloom powder as a waste-based sorbent for cationic dyes removal: equilibrium, kinetic, and thermodynamic studies
Authors: Marzi Khosrowshahi Elnaz , Farhami Nabieh , Jannat Behrooz , Farrokhzadeh Samaneh , Razmi Habib
Published: July 2021

In the present study, for the first time, walnut bloom (WB) powder was used as a natural and economic sorbent for the removal of methylene blue (MB) from an aqueous solution. This new biosorbent was characterized using the following techniques: scanning electron microscopy (SEM), X-ray diffraction (XRD), COHNS, BET (Brunauer–Emmett–Teller) analysis, and Fourier transform infrared (FTIR) spectroscopy. MB removal efficiency and its adsorption onto WB powder were tested in a batch system by varying parameters such as initial dye concentration, contact time, pH, temperature, and dosage of biosorbent in which the removal percentages of ∼92% was achieved under the optimum conditions. Equilibrium data and adsorption isotherms fit well with the Langmuir model (R2 = 0.999, 0 < RL < 1) with a maximum monolayer adsorption capacity of 46 mg g−1. The chemical kinetics of MB adsorption followed the pseudo second-order model. Also, the magnitude of thermodynamic functions identified the removal of MB. ΔH° of –7.32 kJ mol−1and ΔS° of –4.32 kJ mol−1indicated the spontaneity, exothermicity, and favorability of the adsorption process at room temperature.
Visually sorting waste wood — an exploratory study
Authors: Schild Anna , Cool Julie
Published: July 2021

Waste wood collected at the Vancouver landfill has been sorted based on the visibility of coatings, paints, and the green colorization of wood typically associated with wood preservatives. The sorted material was then ground and tested with an inductively coupled plasma mass spectrometry (ICP–MS) for heavy metal elements that are toxic or harmful to humans and (or) the environment. Results indicated that wood preservatives were not visually detectable but paints and coatings were. Therefore, the study demonstrated that visual sorting is not sufficiently accurate to distinguish between treated and clean or untreated waste wood.
Double differential cross section for the single ionization of methane molecule by swift proton projectile
Authors: Askri Souhaila , Sahlaoui Mohammed , Ferouani Abdel Karim , Aïci Lalia , Guedda El Habib , Sekkal Abdessamad
Published: July 2021

In the present work, single ionization of the methane molecule is studied. The double differential cross section for the ejected electron is considered. The target is ionized by the effect of perturbation created by proton impact with high incident velocity. In our theoretical formalism, the one Coulomb wave model is employed in the framework of the first Born approximation, which means that the final state is considered as a product of a plane wave function for the scattered heavy particle and a Coulomb wave function for the ejected electron. The initial state is a product of a plane wave function for the fast incident charge and wave functions centered over the heavy nuclei to describe the active electron. In our formalism, the one Coulomb wave model is corrected by Salin factor to take into account the effect of the electron transfer to the continuum. The obtained results are compared to the available experimental data.
Ab initio investigation on the low-lying states of LaX (X = Se, Sn, Sb)
Authors: Elkahwagy Nagat , Abdelfatah Mahmoud , Ismail Atif
Published: July 2021

Potential energy curves for the low-lying electronic states of the title molecules in their neutral and anionic forms have been calculated by means of the diffusion Monte Carlo method. The effect of different trial functionals has been investigated using single determinants constructed from density functional theory (DFT) orbitals with B3LYP, B3PW91, and M06-2X functions. Bond length, vibrational frequency, and electron affinity have also been numerically derived for the selected species and the ground state has been assigned. Spectroscopic parameters obtained are interpreted and compared to their isovalents, shedding some light on further investigations on the selected dimers.
Next-to-leading-logarithm threshold resummation for exclusive B meson decays
Authors: Zhang Zhi-Qing , Li Hsiang-nan
Published: July 2021

We extend the threshold resummation of the large logarithms $$\ln x$$

ln
x

which appear in factorization formulas for exclusive B meson decays, x being a spectator momentum fraction, to the next-to-leading-logarithm (NLL) accuracy. It is shown that the NLL resummation effect provides suppression in the end-point region with $$x\sim 0$$

x
∼
0

stronger than the leading-logarithm (LL) one, and thus improves perturbative analyses of the above processes. We revisit the $$B\rightarrow K\pi $$

B
→
K
π

decays under the NLL resummation in the perturbative QCD approach, and find that it induces up to 20% variation of the direct CP asymmetries in various modes relative to the LL results. Our method to avoid the Landau singularity in the inverse Mellin transformation causes at most 10% theoretical uncertainty.
Contractible Edges in 3-Connected Cubic Graphs
Authors: Kou Shuai , Qin Chengfu , Yang Weihua
Published: July 2021

An edge [Formula: see text] in a 3-connected graph [Formula: see text] is contractible if the contraction [Formula: see text] is still [Formula: see text]-connected. Let [Formula: see text] be the set of contractible edges of [Formula: see text], [Formula: see text] be the set of vertices adjacent to three vertices of a triangle △. It has been proved that [Formula: see text] in a 3-connected graph [Formula: see text] of order at least 5. In this note [Formula: see text] is a 3-connected cubic graph containing [Formula: see text] triangles, at least [Formula: see text] vertices and with every [Formula: see text] an independent set. Then [Formula: see text]. This is a bound better than [Formula: see text] under some conditions.
Variable mass motion in the Hénon–Heiles system
Authors: Ansari Abdullah A. , Abouelmagd Elbaz I.
Published: July 2021

In this work, we analyze the motion properties of the test particle, that has a variable mass within the frame of Hénon–Heiles system. We derive the equations of motion of the test particle which varies its mass according to Jean’s law. We also determine the quasi-Jacobi integral which shows the effective variation due to variable mass parameters. Further, we studied the locations of stationary points and their stability, after using Meshcherskii spacetime inverse transformations.
A Survey of On-Device Machine Learning
Authors: Dhar Sauptik , Guo Junyao , Liu Jiayi (Jason) , Tripathi Samarth , Kurup Unmesh , Shah Mohak
Published: July 2021

The predominant paradigm for using machine learning models on a device is to train a model in the cloud and perform inference using the trained model on the device. However, with increasing numbers of smart devices and improved hardware, there is interest in performing model training on the device. Given this surge in interest, a comprehensive survey of the field from a device-agnostic perspective sets the stage for both understanding the state of the art and for identifying open challenges and future avenues of research. However, on-device learning is an expansive field with connections to a large number of related topics in AI and machine learning (including online learning, model adaptation, one/few-shot learning, etc.). Hence, covering such a large number of topics in a single survey is impractical. This survey finds a middle ground by reformulating the problem of on-device learning as resource constrained learning where the resources are compute and memory. This reformulation allows tools, techniques, and algorithms from a wide variety of research areas to be compared equitably. In addition to summarizing the state of the art, the survey also identifies a number of challenges and next steps for both the algorithmic and theoretical aspects of on-device learning.
LandmarkMiner
Authors: Li Ruixiang , Xu Rui , Ma Yuanyuan , Luo Xiangyang
Published: July 2021

High-confidence network landmarks are the basis of IP geolocation. However, existing landmarks acquisition methods had weakness such as high time cost and insufficient landmarks number. For this, LandmarkMiner, a street-level network landmarks mining method, is proposed based on service identification and domain name association. First, LandmarkMiner trains classifiers using the scanning results of IPs with known hosting service type, identifies the hosting service type of target IPs using the trained classifiers, and obtains the classified IPs’ domain names using DNS. Then, according to institutional names, a database associating institutional name with possible domain names is built by statistical relationship, which is obtained between the known institutional names and their domain names. Finally, geographical location of IP's domain name after classification is matched in the database and online maps, thereby obtaining landmarks and evaluating reliability of them. LandmarkMiner has mined 9,423 reliable street-level landmarks from 304M IPs in 18 cities. Comparing with existing methods, LandmarkMiner increases the number of reliable street-level landmarks significantly and can be applied in different network connectivity conditions.
Low-Temperature Parylene-Based Adhesive Bonding Technology for 150 and 200 mm Wafers for Fully Biocompatible and Highly Reliable Microsystems
Authors: Selbmann Franz , Baum Mario , Meinecke Christoph , Wiemer Maik , Kuhn Harald , Joseph Yvonne
Published: July 2021

Wafer bonding is a crucial process for fabricating microsystems. Within this study, the polymer parylene was used to establish a low-temperature adhesive wafer bonding process for wafers of 150 and 200 mm diameters. The bonding process was investigated for silicon and glass wafers with different additional coatings including silicon dioxide, silicon nitride, aluminum, and parylene C. Important process parameters such as bonding temperature and time were also investigated and the parylene adhesive was analyzed in detail with respect to its dimensions and type. The performance of the parylene bonding was characterized in different aspects, including mechanical tests, cross-sectional scanning electron microscopy, infrared light transmission, and different hermeticity tests. The reliability of the parylene bonded compounds was also investigated with respect to constant loading, mechanical shocking, and thermal cycling. As a result, the parylene bonding is feasible with various materials and shows high tensile and shear strengths of up to 35 MPa and 80 MPa, respectively. Hermeticity was excellent, with a helium leakage rate lower than 10‒7 mbar∙l s−1. The parylene bonded compounds were proven to feature high reliability. Finally, application of the superior properties of the parylene bonding was demonstrated with respect to the fabrication of different three-dimensional structures.
Research on Stress Distribution Characteristics for Uniquely Shaped Roadway with Hard Roof in Steeply Inclined Coal Seam and Support Technology of Reducing Vibration Impact
Authors: Zhang Junhui , Chen Hui , Shi Xiuzhi , Guan Weiming , Sun Xiaolong
Published: July 2021

This paper presents a comprehensive study of the stress distribution and stability analysis of a uniquely shaped roadway having a steeply dipping hard roof. The coal seam and its roof have a certain impact tendency, which is the internal condition of rock burst. The syncline tectonic stress causes the original rock stress to reach a higher level. The large amount of coal produced in the coal mine and the large movement range of the upper strata cause the huge mining additional stress around the stope. The impact load caused by “cantilever beam” fracture of hard roof can induce and strengthen rock burst. Its engineering geological setting encompasses the mining process and surrounding rock conditions of No. 6 Coal Seam in the 2130 coal mine of Xinjiang. Numerical simulations with theoretical analysis and field measurements investigated a proposed new truss combined support scheme for implementation. A comparison was made of the differences in the state parameters of the road under the new and old support conditions. The application of the new combined support technology changed the form of the stress distribution around the road. Apart from the displacements of the two coal sidewalls, the new support system notably reduced the displacement of roof and floor by 67.8% and 83.6%, respectively. After the implementation of the new support scheme, the frequency of the original rock burst in the working face is greatly reduced, the surrounding rock control and field application effects also remained good, and personnel and equipment safety and production plan have a good guarantee.
Blockchain-Based Key Management and Green Routing Scheme for Vehicular Named Data Networking
Authors: Liu Hao , Zhu Rongbo , Wang Jun , Xu Wengang
Published: July 2021

Due to the distributed and dynamic characteristics of the Internet of Vehicles (IoV) and the continuous growth in the number of devices, content-centric decentralized vehicular named data networking (VNDN) has become more suitable for content-oriented applications in IoV. However, the existing centralized architecture is prone to the failure of single points, which results in trust problems in key verification between cross-domain nodes and consuming more power and reducing the lifetime. Focusing on secure key management and power-efficient routing, this article proposes a blockchain-based key management and green routing scheme for VNDN. A blockchain-based key management scheme is presented to achieve secure and efficient distribution and verification of keys. Specifically, all trusted agencies (TAs) form a consortium blockchain for storing public key hashes to ensure the authenticity of users’ public keys. A green global routing scheme based on node relaying pressure (GGNRP) is proposed to save power consumption and reduce the forwarding delay. A new node relay pressure metric is introduced to assist with routing decisions. Detailed experiments and analysis show that, compared with the existing scheme, the proposed scheme can achieve secure key management and GGNRP can decrease the power consumption and average delay by 15.8% and 63.2%, respectively.
ECG Signal Modeling Using Volatility Properties: Its Application in Sleep Apnea Syndrome
Authors: Faal Maryam , Almasganj Farshad
Published: July 2021

This study presents and evaluates the mathematical model to estimate the mean and variance of single-lead ECG signals in sleep apnea syndrome. Our objective is to use the volatility property of the ECG signal for modeling. ECG signal is a stochastic signal whose mean and variance are time-varying. So, we propose to decompose this nonstationarity into two additive components; a homoscedastic Autoregressive Integrated Moving Average (ARIMA) and a heteroscedastic time series in terms of Exponential Generalized Autoregressive Conditional Heteroskedasticity (EGARCH), where the former captures the linearity property and the latter the nonlinear characteristics of the ECG signal. First, ECG signals are segmented into one-minute segments. The heteroskedasticity property is then examined through various tests such as the ARCH/GARCH test, kurtosis, skewness, and histograms. Next, the ARIMA model is applied to signals as a linear model and EGARCH as a nonlinear model. The appropriate orders of models are estimated by using the Bayesian Information Criterion (BIC). We assess the effectiveness of our model in terms of mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE). The data in this article is obtained from the Physionet Apnea-ECG database. Results show that the ARIMA-EGARCH model performs better than other models for modeling both apneic and normal ECG signals in sleep apnea syndrome.
Grid Impact Assessment of Centralized and Decentralized Photovoltaic-Based Distribution Generation: A Case Study of Power Distribution Network with High Renewable Energy Penetration
Authors: Khatib Tamer , Sabri Lama
Published: July 2021

This paper presents a grid impact assessment of a 5 MWp photovoltaic-based distribution unit on a 33 kV/23 MVA power distribution network with high penetration of renewable energy generation. The adapted network has an average load demand of 23 MVA, with a 3 MWp centralized PV system, and a number of decentralized PV systems of a capacity of 2 MWp. A grid impact assessment is done to an additional 5 MWp of PV generation as a centralized system as well as a number of decentralized systems. Power flow analysis is conducted to the grid considering different generation loading scenarios in order to study grid performance including active and reactive power flow, voltage profiles, distribution power transformers loading, transmission lines ampacity levels, and active and reactive power losses. On the other hand, the distribution of the decentralized systems is done optimally considering power distribution transformer loading and available area using the geographical information system. Finally, an economic analysis is done for both cases. Results showed that grid performance is better considering decentralized PV systems, whereas the active power losses are reduced by 13.43% and the reactive power losses are reduced by 14.48%. Moreover, the voltage of buses improved as compared to the centralized system. However, the decentralized PV systems were found to affect the power quality negatively more than the centralized system. As for the economic analysis, the decentralized PV system option is found slightly less profitable than the centralized system, whereas the simple payback period is 9 and 7 years, respectively. However, decentralized PV systems are recommended considering the technical implications of the centralized PV system.
LINC00665 Facilitates the Malignant Processes of Osteosarcoma by Increasing the RAP1B Expression via Sponging miR-708 and miR-142-5p
Authors: Wang Limin , Song Xinghua , Yu Lijun , Liu Bing , Ma Jinfeng , Yang Weihua
Published: July 2021

Osteosarcoma (OS) is a kind of fatal primary bone tumors in adolescents and young adults. Long noncoding RNAs (lncRNAs) are a group of noncoding RNAs which occupy a part of the latest hot topics. We aimed to investigate the roles of lncRNA LINC00665 in OS in this study. In this study, we found that LINC00665 was highly expressed in OS tissues and cell lines, and its high expression was associated with malignant feature and poor prognosis of OS. In OS cells, LINC00665 could facilitate the proliferation, migration, and invasion to play an oncogenic role. Mechanistically, LINC00665 served as a sponge for miR-708 and miR-142-5p and positively mediated the expression of their target RAP1B. Finally, we confirmed that LINC00665 exercised its biological functions by mediating RAP1B. In conclusion, LINC00665 is overexpressed in OS and facilitates the malignant processes of OS cells by increasing the RAP1B expression via sponging miR-708 and miR-142-5p.
Effect of Low Atmospheric Pressure on Bubble Stability of Air‐Entrained Concrete
Authors: Li Xuefeng , Yang Pengyu
Published: July 2021

The effect of low atmospheric pressure of the environment on the air content and bubble stability of air‐entrained concrete was investigated in Beijing and Lhasa. The results indicate that the reduction of atmospheric pressure can weaken the air‐entraining capability of air‐entraining agents (AEAs). The air content of fresh concrete decreased by 9%–39% when the atmospheric pressure dropped to 64 kPa. The bubble stability of concrete mixed at a low atmospheric pressure becomes worse. Within 50–55 min after mixing, the air content of concrete mixed at a low atmospheric pressure decreases greatly, and the void spacing factor increases obviously. The concrete mixed at a low atmospheric pressure will lose more air content when vibration time increases, leading to the decrease of air content and the increase of the spacing factor, which are more significant than the concrete mixed at normal atmospheric pressure. On the basis of the experiment results in this study, the type of AEAs must be carefully selected, and the vibration time must be strictly controlled to ensure that the air content of concrete will meet the design requirements in low atmospheric pressure areas.
Simulation of the Compressive Strength of Cemented Tailing Backfill through the Use of Firefly Algorithm and Random Forest Model
Authors: Wang Qi-Ang , Zhang Jia , Huang Jiandong
Published: July 2021

Cemented tailings backfill is widely used in worldwide mining areas, and its development trend is increasing due to the technical and economic benefits. However, there is no reliable and simple machine learning model for the prediction of the compressive strength. In the present study, the research process to use artificial intelligence algorithms to predict the compressive strength of cemented tailing backfill was conducted, overcoming the shortcomings of traditional empirical formulas. Experimental tests to measure the compressive strength of cemented tailing backfill were conducted to construct the dataset for the machine learning. Five input parameters (tailing to cement ratio, percentage of fine tailings, cement type, curing time, and solid to water ratio) were considered for the design of the laboratory tests. The firefly algorithm (FA) was used to tune the random forest (RF) hyperparameters, and it was adopted to combine the RF model to improve the accuracy and efficiency for the prediction of the compressive strength of the cemented tailing backfill. By comparing the predicted and actual results, the reliability and accuracy of the prediction model proposed are confirmed. Tailing to cement ratio and curing time are the two most important parameters to the compressive strength of the cemented tailing backfill.
Culex (Diptera: Culicidae) Mosquitoes in Jazan Region, Saudi Arabia, and Their Molecular Identification
Authors: Noureldin Elsiddig , Dafalla Ommer , Hakami Abdualziz , Jubran Mohammed , Alzhrani Ahmed , Mujally Muhannad , Shajari Othman , Khardali Ali , Eisa Zaki
Published: July 2021

Morphological characteristics have been the gold standard method to identify mosquito species. However, morphological identification has many limitations including lack of expertise and damaging of external characters due to improper specimen handling. Therefore, we used the polymerase chain reaction technique (PCR) as an integrated tool to identify Culex mosquito species to establish a more precise and reliable identification system related to their spatial distribution in Jazan region. We identified Culex mosquito species and subspecies using taxonomic keys, and then we used the polymerase chain reaction technique (PCR) as an integrated tool to confirm and refine the list of Culex mosquito species in the region. Phylogenetic trees were constructed for the identified species, and their distinctive clustering was compared with their reference’s species in the GenBank. We identified 7026 adult Culex mosquitoes belonging to 4 species. Culex tritaeniorhynchus was the predominant species (45%), followed by Cx. quinquefasciatus (32%), then Culex sitiens (20%), and Cx. pipiens (3%). The most infested areas by Culex in the region were Gizan and Sabya. The PCR achieved 100% success in identifying the four Culex mosquito species. We also report the molecular identification of Cx. quinquefasciatus and Cx. pipiens species for the first time in Jazan region while the molecular identification of Cx. tritaeniorhynchus and Cx. sitiens was reported for the first time in Jazan region and the whole Saudi Arabia. This study utilized for the first time PCR to identify Culex mosquito species in Jazan region. The PCR is a complementary and integrated taxonomy-based identification tool for mosquito species. This integration has the capacity to promote and enhance vector surveillance and control programs, as well as defining the genetic diversity of species in the region.
Vertical Expansion Stability of an Existing Landfill: A Case Study of a Landfill in Xi’an, China
Authors: Sheng Hui , Ren Yinbang , Huang Man , Zhang Zhenying , Lan Jiwu
Published: July 2021

The vertical expansion of existing landfills can hold significant amounts of domestic waste and solve practical difficulties such as local government site selection. This research topic has become increasingly popular in the field of environmental geotechnical engineering. This study examined vertical expansion stability of landfills considering high leachate water level. The results showed the following. (1) Four slope instability modes for landfill vertical expansion are categorized according to the following slip surface positions: shallow slippage of the existing landfill, shallow slippage of the expanding landfill, interface slip between the existing landfill and expanding landfill, and deep slippage passes through the foundation soil. (2) The factor of safety decreases as the height of leachate level increases. When the height of leachate level rises from 2 m to 20 m, the factor of safety of the landfill is reduced by 13.2–15.4%. (3) As the vertical expansion height increases, the factor of safety of the existing landfill decreases, and when the expansion height increases to 30 m, the stability factor of safety of the old waste landfill is reduced by 4.83%. A landfill in Xi’an is considered as an example for the analysis, which shows that a leachate drainage layer can discharge leachate from the landfill body efficiently, reduce the leachate level height of the landfill body, and improve the stability of vertical expansion of the landfill. This study and its findings can be used as a reference for similar expansion projects.
Directional Itinerary Planning for Multiple Mobile Agents in Wireless Sensor Networks
Authors: Bendjima Mostefa , Feham Mohammed , Lehsaini Mohamed
Published: July 2021

Currently, the majority of research in the area of wireless sensor networks (WSNs) is directed towards optimizing energy use during itinerary planning by mobile agents (MAs). The route taken by the MA when migrating can get a significant effect on energy consumption and the lifespan of the network. Conversely, finding an ideal arrangement of Source Nodes (SNs) for mobile agents to visit could be a problematic issue. It is within this framework that this work focused on solving certain problems related to itinerary planning based on a multimobile agent (MMA) strategy in networks. The objective of our research was to increase the lifespan of sensor networks and to diminish the length of the data collection task. In order to achieve our objective, we proposed a new approach in WSNs, which took into consideration the criterion of an appropriate number of MAs, the criterion of the appropriate grouping of SNs, and finally the criterion of the optimal itinerary followed by each MA to visit all its SNs. Thus, we suggested an approach that may be classified as a centralized planning model where the itinerary schedule is entirely shaped by the base station (sink) which, unlike other approaches, is no longer constrained by energy consumption. A series of simulations to measure the performance of the new planning process was also carried out.
Zinc Supplementation Prevented Type 2 Diabetes-Induced Liver Injury Mediated by the Nrf2-MT Antioxidative Pathway
Authors: Yu Lechu , Liu Yuanyuan , Jin Yichun , Liu Tinghao , Wang Wenhan , Lu Xuemian , Zhang Chi
Published: July 2021

Zinc is an essential trace element that is often reduced under the type 1 diabetic condition. Previous studies demonstrated that zinc deficiency enhanced type 1 diabetes-induced liver injury and that zinc supplementation significantly helped to prevent this. Due to the differences in pathogenesis between type 1 and type 2 diabetes, it is unknown whether zinc supplementation can induce a beneficial effect on type 2 diabetes-induced liver injury. This possible protective mechanism was investigated in the present study. A high-fat diet, along with a one-time dose of streptozotocin, was applied to metallothionein (MT) knockout mice, nuclear factor-erythroid 2-related factor (Nrf) 2 knockout mice, and age-matched wild-type (WT) control mice, in order to induce type 2 diabetes. This was followed by zinc treatment at 5 mg/kg body weight given every other day for 3 months. Global metabolic disorders of both glucose and lipids were unaffected by zinc supplementation. This induced preventive effects on conditions caused by type 2 diabetes like oxidative stress, apoptosis, the subsequent hepatic inflammatory response, fibrosis, hypertrophy, and hepatic dysfunction. Additionally, we also observed that type 2 diabetes reduced hepatic MT expression, while zinc supplementation induced hepatic MT expression. This is a crucial antioxidant. A mechanistic study showed that MT deficiency blocked zinc supplementation-induced hepatic protection under the condition of type 2 diabetes. This suggested that endogenous MT is involved in the hepatic protection of zinc supplementation in type 2 diabetic mice. Furthermore, zinc supplementation-induced hepatic MT increase was unobserved once Nrf2 was deficient, indicating that Nrf2 mediated the upregulation of hepatic MT in response to zinc supplementation. Results of this study indicated that zinc supplementation prevented type 2 diabetes-induced liver injury through the activation of the Nrf2-MT-mediated antioxidative pathway.
Study on Compaction and Machinability of Silicon Nitride (Si3N4) Reinforced Copper Alloy Composite through P/M Route
Authors: Sathish T. , Mohanavel V. , Karthick Alagar , Arunkumar M. , Ravichandran M. , Rajkumar S.
Published: July 2021

Nowadays, most of the products are used in the electrical and electronics field, and copper alloy is playing a significant role such as Springs for relay contacts and switchgear, Rotor bars, and Busbars. In this work, the copper alloys consider as base alloy, and the reinforced factor of silicon nitride (Si3N4) is processed of reinforcement as 3 wt. %, 6 wt. %, 9 wt. %, 12 wt. % Si3N4 through powder metallurgy performance. The ball mill process is used for this work to obtain an enhanced homogeneous mixture of both base material as well as reinforced particles. Using a hydraulic press, the blended powders are compacted with applying 3 kN and 10 min period for obtained good strength of green compact specimens. Further, the green compacted specimens are sintered, and the sintered billets are machined in the conventional lathes with different cutting speeds 50 m/min, 100 m/min, and 150 m/min; feed rate of 0.1 mm/rev (fixed); and depth of cut of 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, and 1.6 mm. Cutting speed and depth of cut to find the composites’ cutting force is ingenious. A wear test also can be conducted to find the wear resistance of the reinforced particles of the copper alloy material.