bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of transfusion‐transmitted hepatitis A through postdonation information in Korea: results of an HAV lookback (2007‐2012)
Authors: Kim M. J. , Shin J. Y. , Oh J. A. , Jeong K. E. , Choi Y. S. , Park Q. , Song M. S. , Lee D. H.
Published: July 2018

Background and Objectives

Despite safety measures to minimize the risk of transfusion‐transmitted infections, a residual risk remains. To trace and review some such cases, we ask donors to notify the blood centre if they are diagnosed with an infection after they donate blood.

Materials and Methods

We analysed all data on postdonation cases of hepatitis A reported between 2007 and 2012. Archived specimens from these donors were tested for hepatitis A virus (HAV) using anti‐HAV IgM/IgG and HAV‐PCR as markers. If any of the test results were positive, we reviewed the medical records of the recipients and, if necessary, tested them for hepatitis A.

Results

Fifteen blood donors notified the blood centres of having been diagnosed with hepatitis A after donation. All archived samples except for one were HAV‐PCR‐positive and anti‐HAV IgM/IgG‐negative. Of the donated components, four RBCs and 14 FFPs had not been transfused to patients and were recalled. Among 26 recipients of the implicated components, fourteen were still alive when they were notified. Two patients showed clinical symptoms of hepatitis A and had positive results with anti‐HAV IgM.

Conclusion

Transfusion‐transmitted hepatitis A is rare but exists. To reduce the risk, donors should be told to notify the blood centre if they are diagnosed with blood‐borne diseases after they donate blood. Physicians should consider the possibility of transfusion‐transmitted hepatitis A if a transfused patient has hepatitis A but no history of travel or route of faecal‐oral infection.
Particle Image Velocimetry Measurements of Aeroacoustic Sources of a Shallow Cavity in a Pipeline
Authors: Mohamed S. , Ziada S.
Published: July 2018

The aeroacoustic sources generated by flow over a ducted shallow cavity in the presence of a longitudinal plane sound wave are examined at various Strouhal numbers and sound intensities. The cavity is exposed to high Reynolds number fully developed pipe flow. Extensive particle image velocimetry (PIV) flow measurements are performed to characterize the unsteady velocity field and finite element analysis is used to obtain the acoustic velocity field. Howe's aeroacoustic integrand is then used to compute the spatial and temporal distributions of the aeroacoustic sources resulting from the cavity shear layer interaction with the sound field. The results show two aeroacoustic sources separated by a sink along the cavity shear layer. This distribution is different from that reported for the closed side-branch resonance case, which shows a single source at the downstream corner and a sink at the upstream corner of the cavity. The effect of the upstream corner geometry in the present case is, therefore, expected to be different from the case of side-branch resonance. The time-averaged sound power distribution is computed and the total sound power per cycle is compared with the aeroacoustic source strength measured by means of the standing wave method (SWM) (Mohamed, S., Graf, H. R., and Ziada, S., 2011, “Aeroacoustic Source of a Shallow Cavity in a Pipeline,” ASME Paper No. PVP2011-57437). The merits of these two methods in determining the aeroacoustic sources are highlighted.
Improvements to the ASME B31.8 Dent Strain Equations
Authors: Okoloekwe Chike , Aranas Nikko , Kainat Muntaseer , Langer Doug , Hassanien Sherif , Roger Cheng J. J. , Adeeb Samer
Published: July 2018

Pipelines used to transport oil and gas products are often subjected to external forces during its construction or operation, which can result in the formation of dents in the pipe. Various pipeline codes have stipulations on how a dent's severity can be ascertained in order to prioritize repairs. The most prominent being the depth-based criterion, which determines the severity of a dent by its depth. The depth-based criterion fails to consider the fact that the geometry of the dent can result in high strain concentration and eventually lead to integrity issues at the dented region. Alternatively, the strains associated with the dent can be an indicator of the dent's severity. Nonmandatory codified equations are available for evaluating the strains at the dented region of the pipe. The current implementation of these equations might fail to capture the strains that are not aligned with the most severe deformation profile of the dent and as such a global view of the strain distribution of the dented profile would be more informative as per the localized strain distribution. The study presented herein is the implementation of ASME B31.8 formulations together with the suggested modifications to evaluate the three-dimensional (3D) strain state of the dented pipe. The strain distributions obtained are compared against the strains predicted by finite element analysis (FEA) model. The correlation in the predicted strains indicates the possibility of the rapid and concise strain based characterization of dented pipes with the proposed technique.
Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps
Authors: Kiani Mahdi , Walker Roger , Babaeidarabad Saman
Published: July 2018

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.
Using Hands-On Physical Computing Projects to Teach Computer Programming to Biomedical Engineering Students
Authors: Ham Trevor , Cyrus Rezvanifar S. , Thomas Vineet S. , Amini Rouzbeh
Published: July 2018

Rapid advancements in the multidisciplinary field of biomedical engineering (BME) require competitive engineers with skill sets in a broad range of subjects including biology, physiology, mechanics, circuits, and programming. Accordingly, such a need should be reflected in the training of BME students. Among those skills, computer programming is an essential tool that is used in a wide variety of applications. In this paper, we have provided our experience in incorporating project-based learning, a promising approach in active learning, for teaching computer programming to BME students. We describe a low-cost method for using physical, hands-on computing that directly relates to BME. Additionally, we detail our efforts to teach multiple programming languages in one semester and provide a detailed analysis of the outcomes. We also provide basic materials for other instructors to adapt to fit their own needs.
Effect of Weld Cooling Rates on Mechanical and Metallurgical Properties of Submerged Arc Welded Pressure Vessel Steel
Authors: Arya Harish Kumar , Singh Kulwant , Saxena R. K.
Published: July 2018

Submerged arc welding of SA 516 grade 60 pressure vessel grade steel was conducted with different heat plate thicknesses and the influence of cooling rate on microstructure, Vickers hardness, and impact toughness of heat affected zone (HAZ) of weldment was systematically investigated. Weld cooling rates vary with change in heat input or variation in plate thickness of base metal. Results showed that thin plates accumulate the heat, which cause grain coarsening and loss of acicular ferrite (AF) microstructure, which is further responsible for lower impact strength of welded joint. It is deemed that faster cooling rates due to heat sink in thickness direction with thick plates cause high percentage of AF with finer grain and enhanced hardness values. Improved impact strength with thick plates with same heat input signifies that supplying heat more than required to thin plates may cause microstructural deterioration and responsible for impact strength loss of weldments. Test demonstrates that the cooling rate should be above 15 °C/s to keep impact strength loss within considerable limits.
Fracture Behavior Simulation of a High-Pressure Vessel Under Monotonic and Fatigue Loadings
Authors: Nie Defu , Otsuka Yuichi , Mutoh Yoshiharu
Published: July 2018

Fracture behavior of a high-pressure vessel for food processing under monotonic and fatigue loadings was investigated by conducting both experiments and finite element analysis (FEA) based on abaqus and zencrack software. Finite element analysis results showed that cracks nucleated at the filets of pin-hole and propagated faster near the inner surface than near the outer surface of the pressure vessel, progressively deflected, and eventually coalesced with other cracks initiated from the counter pin hole under monotonic loading. Such crack growth behavior coincided with the experimental result of hydraulic pressurizing test. Based on fatigue crack growth test of the pressure vessel material, 17-4PH stainless steel, a new equation to express the da/dN−ΔK curves including threshold region, has been proposed and embedded into the zencrack software to simulate the fatigue behavior of the pressure vessel. The simulation results showed that fatigue lives could be accurately estimated including low pressure range. The present simulation methods would be the useful design tool for pressure vessel under monotonic and cyclic loadings.
Improving Biomedical Engineering Education Through Continuity in Adaptive, Experiential, and Interdisciplinary Learning Environments
Authors: Singh Anita , Ferry Dawn , Mills Susan
Published: July 2018

This study reports our experience of developing a series of biomedical engineering (BME) courses having active and experiential learning components in an interdisciplinary learning environment. In the first course, BME465: biomechanics, students were immersed in a simulation laboratory setting involving mannequins that are currently used for teaching in the School of Nursing. Each team identified possible technological challenges directly related to the biomechanics of the mannequin and presented an improvement overcoming the challenge. This approach of exposing engineering students to a problem in a clinical learning environment enhanced the adaptive and experiential learning capabilities of the course. In the following semester, through BME448: medical devices, engineering students were partnered with nursing students and exposed to simulation scenarios and real-world clinical settings. They were required to identify three unmet needs in the real-world clinical settings and propose a viable engineering solution. This approach helped BME students to understand and employ real-world applications of engineering principles in problem solving while being exposed to an interdisciplinary collaborative environment. A final step was for engineering students to execute their proposed solution from either BME465 or BME448 courses by undertaking it as their capstone senior design project (ENGR401-402). Overall, the inclusion of clinical immersions in interdisciplinary teams in a series of courses not only allowed the integration of active and experiential learning in continuity but also offered engineers more practice of their profession, adaptive expertise, and an understanding of roles and expertise of other professionals involved in enhancement of healthcare and patient safety.
Balancing Academic Rigor and Creative Thinking: A Transformational Approach to Teaching Senior Design
Authors: Pfeiffer Ferris M. , Burgoyne Suzanne , Hunt Heather K. , Strobel Johannes
Published: July 2018

Innovation arises from creativity. “Thinking outside the box” has long been seen as a necessary precursor to innovation and invention in engineering. However, creativity is rarely part of traditional engineering curricula. In 2015, our group began to explore integrating theater-based creativity methods into bioengineering capstone design. Evaluation of student outcomes was encouraging, so we continued to develop the course in 2016 and 2017. As we worked to refine the pedagogical process, we discovered tensions (real or perceived) between providing academic rigor and allowing students to embrace their creativity; for instance, we experienced some resistance from engineering faculty and students toward adopting methods they viewed as “artsy” or lacking academic rigor. Here, we discuss the tensions we observed offer potential ways to mitigate such tensions and begin to consider how to expand on our successes.
An active control strategy for the scattered sound field control of a rigid sphere
Authors: Liu Jingwei , Wang Xiaolin , Wu Ming , Yang Jun
Published: July 2018

This article proposes a control strategy that combines optimized loudspeaker arrays using constrained matching pursuit and zero pressure constrained points. The proposed control strategy is used to optimize the loudspeaker placement of an active control system that aims to control the scattered sound field of a rigid sphere. Compared to the strategy employing uniformly placed loudspeaker arrays, the proposed control strategy has a better reduction performance in the square target area and less amplification in other areas. This advantage becomes greater with increases in the power constraint on the secondary loudspeaker and the frequency of the primary field.
Onset of Accelerated Muscle Deoxygenation During the 20-m Shuttle Run Test in Boys
Authors: Kume Daisuke , Iguchi Akira , Endoh Hiroshi
Published: July 2018

Purpose: This study aimed to compare the relative exercise intensity at which the onset of accelerated muscle deoxygenation occurs during the 20-m shuttle run test (20mSRT) between boys and men and to examine whether the timing of the onset of acceleration appearance is related to 20mSRT performance in boys. Methods: Twenty-four boys performed the 20mSRT, during which concentration changes in oxygenated and deoxygenated hemoglobin and myoglobin (ΔOxy-Hb and ΔDeoxy-Hb, respectively) in the m. vastus lateralis were monitored using a portable near-infrared spectroscopy device. The boys’ data were compared with those of 29 men in a previous study. Results: An onset of accelerated decrease in Δ[Oxy-Hb − Deoxy-Hb] was found in 11 of the 24 boys (45.8%) and 20 of the 29 men (69.0%) and was found at a higher relative exercise intensity in the boys than in the men. The number of laps at which the onset of acceleration occurred correlated with total laps in the boys (r = .87). Conclusions: These findings demonstrate that the onset of accelerated muscle deoxygenation during the 20mSRT occurs at a higher relative exercise intensity in boys than in men. Our findings also show that the timing of the onset of acceleration appearance is associated with 20mSRT performance in boys.
In Vitro
MIC Values of Rifampin and Ethambutol and Treatment Outcome in Mycobacterium avium Complex Lung Disease
Authors: Kwon Byoung Soo , Kim Mi-Na , Sung Heungsup , Koh Younsuck , Kim Woo-Sung , Song Jin-Woo , Oh Yeon-Mok , Lee Sang-Do , Lee Sei Won , Lee Jae-Seung , Lim Chae-Man , Choi Chang-Min , Huh Jin-Won , Hong Sang-Bum , Park Sojung , Shim Tae Sun , Chong Yong Pil , Jo Kyung-Wook
Published: July 2018

Although it is known that the
in vitro
MICs of rifampin and ethambutol are poorly correlated with the clinical response in
Mycobacterium avium
complex (MAC) lung disease (MAC-LD), evidence for this is limited. This study investigated the association between treatment outcome and the
in vitro
MICs of rifampin and ethambutol in patients with MAC-LD.
Broad Spectrum and Safety of Oral Treatment with a Promising Nitrosylated Chalcone in Murine Leishmaniasis
Authors: Sousa-Batista Ariane J. , Escrivani-Oliveira Douglas , Falcão Camila Alves Bandeira , Philipon Cintia Iana Monteiro da Silva , Rossi-Bergmann Bartira
Published: July 2018

The oral efficacy and safety of a leishmanicidal nitrochalcone (CH8) were studied in BALB/c mouse infections with
Leishmania amazonensis
and
Leishmania infantum
. Although 10-fold-higher doses of CH8 were needed to produce the same antiparasitic effect as that seen with the reference drug miltefosine, the latter was nephrotoxic, whereas CH8 restored disease toxicity markers to normal.
Screening of Preselected Libraries Targeting Mycobacterium abscessus for Drug Discovery
Authors: Richter Adrian , Strauch Angelika , Chao Joseph , Ko Mary , Av-Gay Yossef
Published: July 2018

Mycobacterium abscessus
is intrinsically resistant to many antimycobacterial antibiotics, which presents serious problems in therapy. Here, we describe the development of a novel phenotype-based microscopic and computerized imaging drug screening approach.
Validation of Heel Stick Microsampling To Optimize Micafungin Doses in Neonates and Young Infants
Authors: Auriti Cinzia , Goffredo Bianca Maria , Ronchetti Maria Paola , Piersigilli Fiammetta , Cairoli Sara , Bersani Iliana , Dotta Andrea , Pai Manjunath P.
Published: July 2018

Major gaps exist in our knowledge of antimicrobial pharmacokinetics in critically ill neonates and infants that require validated microsampling and bioanalysis methods to support therapeutic drug monitoring. We compared serially collected intravenous (i.v.) and heel stick capillary (HSC)-sampled plasma concentrations of micafungin (8 mg/kg) in eight infants born preterm with systemic candidiasis.
Bacterial Endospores as Phage Genome Carriers and Protective Shells
Authors: Gabiatti Naiana , Yu Pingfeng , Mathieu Jacques , Lu Grant W. , Wang Xifan , Zhang Hangjun , Soares Hugo M. , Alvarez Pedro J. J.
Published: July 2018

Bacteriophages are being considered for the control of multidrug-resistant and other problematic bacteria in environmental systems. However, the efficacy of phage-based microbial control is limited by infectivity loss during phage delivery and/or storage. Here, we exploit the pseudolysogenic state of phages, which involves incorporation of their genome into bacterial endospores (without integration into the host chromosome), to enhance survival in unfavorable environments. We isolated polyvalent (broad-host-range) phages that efficiently infect both benign and opportunistically pathogenic
Bacillus
strains and encapsulated the phage genomes in
B. subtilis
endospores to significantly improve resistance to various environmental stressors. Encapsulation by spores also significantly enhanced phage genome viability during storage. We also show that endospore germination can be induced on demand with nutrient germinants that trigger the release of active phages. Overall, we demonstrate that encapsulation of polyvalent phage genomes into benign endospores holds great promise for broadening the scope and efficacy of phage biocontrol.
Rickettsia Lipid A Biosynthesis Utilizes the Late Acyltransferase LpxJ for Secondary Fatty Acid Addition
Authors: Guillotte Mark L. , Gillespie Joseph J. , Chandler Courtney E. , Rahman M. Sayeedur , Ernst Robert K. , Azad Abdu F.
Published: July 2018

Lipopolysaccharide (LPS) triggers an inflammatory response through the TLR4-MD2 receptor complex and inflammatory caspases, a process mediated by the lipid A moiety of LPS. Species of
Rickettsia
directly engage both extracellular and intracellular immunosurveillance, yet little is known about rickettsial lipid A. Here, we demonstrate that the alternative lipid A acyltransferase, LpxJ, from
Rickettsia typhi
and
R. rickettsii
catalyzes the addition of C
16
fatty acid chains into the lipid A 3′-linked primary acyl chain, accounting for major structural differences relative to the highly inflammatory lipid A of
Escherichia coli
.
Phosphatase Cdc25A Negatively Regulates the Antiviral Immune Response by Inhibiting TBK1 Activity
Authors: Qi Dandan , Hu Lei , Jiao Tong , Zhang Tinghong , Tong Xiaomei , Ye Xin
Published: July 2018

The RLR-mediated antiviral immune response is critical for host defense against RNA virus infection. However, the detailed mechanism for balancing the RLR signaling pathway in host cells is not well understood. We found that the phosphatase Cdc25A negatively regulates the RNA virus-induced innate immune response. Our studies indicate that Cdc25A inhibits the RLR signaling pathway via its phosphatase activity. We demonstrated that Cdc25A reduces TBK1 activity and consequently restrains the activation of IFN-β transcription as well as the antiviral status of nearby cells. We showed that Cdc25A can also inhibit DNA virus-induced activation of IFN-β. Taken together, our findings uncover a novel function and mechanism for Cdc25A in regulating antiviral immune signaling. These findings reveal Cdc25A as an important negative regulator of antiviral immunity and demonstrate its role in maintaining host cell homeostasis following viral infection.
Genes within Genes in Bacterial Genomes
Authors: Meydan Sezen , Vázquez-Laslop Nora , Mankin Alexander S.
Published: July 2018

Genetic coding in bacteria largely operates via the “one gene-one protein” paradigm. However, the peculiarities of the mRNA structure, the versatility of the genetic code, and the dynamic nature of translation sometimes allow organisms to deviate from the standard rules of protein encoding. Bacteria can use several unorthodox modes of translation to express more than one protein from a single mRNA cistron. One such alternative path is the use of additional translation initiation sites within the gene. Proteins whose translation is initiated at different start sites within the same reading frame will differ in their N termini but will have identical C-terminal segments. On the other hand, alternative initiation of translation in a register different from the frame dictated by the primary start codon will yield a protein whose sequence is entirely different from the one encoded in the main frame. The use of internal mRNA codons as translation start sites is controlled by the nucleotide sequence and the mRNA folding. The proteins of the alternative proteome generated via the “genes-within-genes” strategy may carry important functions. In this review, we summarize the currently known examples of bacterial genes encoding more than one protein due to the utilization of additional translation start sites and discuss the known or proposed functions of the alternative polypeptides in relation to the main protein product of the gene. We also discuss recent proteome- and genome-wide approaches that will allow the discovery of novel translation initiation sites in a systematic fashion.
Sponges and Predators in the Small RNA World
Authors: Figueroa-Bossi Nara , Bossi Lionello
Published: July 2018

Most noncoding small RNAs (sRNAs) that regulate gene expression do so by base-pairing with mRNAs, affecting their translation and/or stability. Regulators as evolutionarily distant as the
trans
-encoded sRNAs of bacteria and the microRNAs (miRNAs) of higher eukaryotes share the property of targeting short sequence segments that occur in multiple copies in bacterial and eukaryotic transcriptomes. This target promiscuity has major implications for sRNA function. On the one hand, it allows the sRNA to coordinately control several different targets and thus be at the center of regulatory networks. On the other hand, it allows the existence of target mimics or decoys that divert the sRNA/miRNA away from bona fide targets and thus serve as mechanisms to regulate the regulator. In addition, by competing for pairing with the same sRNA, bona fide targets establish a cross talk that can impact on each other’s expression levels. Here we review evidence that target mimicry and competition are important components of the regulatory architecture of bacterial sRNA networks.
Ten simple rules for conducting umbrella reviews
Authors: Fusar-Poli Paolo , Radua Joaquim
Published: July 2018

Objective

Evidence syntheses such as systematic reviews and meta-analyses provide a rigorous and transparent knowledge base for translating clinical research into decisions, and thus they represent the basic unit of knowledge in medicine. Umbrella reviews are reviews of previously published systematic reviews or meta-analyses. Therefore, they represent one of the highest levels of evidence synthesis currently available, and are becoming increasingly influential in biomedical literature. However, practical guidance on how to conduct umbrella reviews is relatively limited.

Methods

We present a critical educational review of published umbrella reviews, focusing on the essential practical steps required to produce robust umbrella reviews in the medical field.

Results

The current manuscript discusses 10 key points to consider for conducting robust umbrella reviews. The points are: ensure that the umbrella review is really needed, prespecify the protocol, clearly define the variables of interest, estimate a common effect size, report the heterogeneity and potential biases, perform a stratification of the evidence, conduct sensitivity analyses, report transparent results, use appropriate software and acknowledge the limitations. We illustrate these points through recent examples from umbrella reviews and suggest specific practical recommendations.

Conclusions

The current manuscript provides a practical guidance for conducting umbrella reviews in medical areas. Researchers, clinicians and policy makers might use the key points illustrated here to inform the planning, conduction and reporting of umbrella reviews in medicine.
What factors can influence the reproductive phenology of Neotropical Piper species (Piperaceae) in a semi-deciduous seasonal forest?
Authors: Valentin-Silva Adriano , Staggemeier Vanessa Graziele , Batalha Marco Antonio , Guimarães Elza
Published: July 2018

Plant phenophases can be modulated by abiotic factors as well as by evolutionary history. We tested the influence of factors shaping the reproductive phenology of 17 co-occurring Piper species in a semi-deciduous seasonal forest in southeastern Brazil over a 12 month period. We describe the phenology, applying circular statistics to the flowering and fruiting phenophases for each species. Mantel correlation tests were conducted to investigate the role of phylogeny in phenological responses, and the influence of abiotic variables (temperature, rainfall, and day length) was analyzed using generalized linear models. Additionally, we tested whether the presence of latent flower buds influenced flowering and fruiting times. The phenological variation across species of Piper in the reproductive stages was not phylogenetically structured. Flowering and fruiting occurred throughout the year, but higher seasonality was detected in the flowering phase, which positively correlated with long days (∼13 h). The flowering phase was shorter and occurred earlier in Piper species with latent flower buds than in species without them, probably because these species are better adjusted to respond when climate conditions are favorable for flower anthesis. Thus, abiotic factors and the presence of latent flower buds shape the reproductive phenology of Piper species.
How coexistence may influence life history: the reproductive strategies of sympatric congeneric terrestrial isopods (Crustacea, Oniscidea)
Authors: Zimmermann Bianca Laís , Palaoro Alexandre Varaschin , Bouchon Didier , Almerão Maurício Pereira , Araujo Paula Beatriz
Published: July 2018

Patterns of allocation between reproduction, survival, and maintenance are what we call life history. By investigating the life-history strategy of sympatric species, we may understand how they are able to coexist, as different strategies are expected to evolve in species that occupy similar niche space. Terrestrial isopods are a group in which multiple species frequently inhabit the same area. Notably, they are usually infected by Wolbachia Hertig, 1936, a notorious manipulator of the hosts’ reproductive processes. Thus, the aim of this study was to analyze the investment in reproduction in three sympatric and closely related species of terrestrial isopods: Atlantoscia floridana (Van Name, 1940), Atlantoscia inflata Campos-Filho and Araujo, 2015, and Atlantoscia petronioi Campos-Filho, Contreira and Lopes-Leitzke, 2012, only the latter being infected with Wolbachia. We showed that the presence of the bacteria seems not to affect the fitness of A. petronioi, because there was no clear difference in the reproductive output of infected and noninfected individuals. On the other hand, we observed that the three species possess alternative life-history strategies; that is, they differ in how much they invest in maintenance (body size) and reproductive effort. Such differences probably facilitate the species coexistence, reducing the competition among them.
Dynamic modeling of aircraft landing gear and multi-objective optimization with simple cell mapping method
Authors: Wu Wei-Guo , Xiong Fu-Rui , Sun Jian-Qiao , Leng Yong-Gang
Published: July 2018

To study the dynamic characteristics of aircraft landing gear and carry out successive optimizations, a mathematical model of flexible landing gear is established by the Hamiltonian principle. The dynamic model includes a tire force estimation derived from the impact model. Dynamic analysis with the flexible model is then conducted. Stress distribution is obtained from the dynamic analysis, which can be used for fatigue analysis, optimization design, etc. To achieve better dynamic characteristics in terms of vibration reduction, a multi-objective optimization problem is formulated and solved via a simple cell mapping algorithm. Optimal simulations indicate the quality of optimal structural designs. Compared with the baseline structure, candidate optimal designs can improve dynamic performance of fuselage vibration suppression, shock absorber efficiency, and stress settling time. The proposed multi-objective optimal parameter design provides a fast tuning procedure that saves considerable time compared to finite element method-based optimization. In addition, the optimal parameter set provides useful interface information for detailed landing gear structural modeling that serves other analysis purposes.
Time fractional modified anomalous sub-diffusion equation with a nonlinear source term through locally applied meshless radial point interpolation
Authors: Shivanian Elyas , Jafarabadi Ahmad
Published: July 2018

In this paper, an alternative approach of spectral meshless radial point interpolation (SMRPI) is applied to the modified anomalous fractional sub-diffusion equation with a nonlinear source term in one and two dimensions. The time fractional derivative is described in the Riemann–Liouville sense. The applied approach is based on a combination of meshless methods and the spectral collocation techniques. The point interpolation method with the help of radial basis functions is used to construct the shape functions which act as basis functions in the frame of the SMRPI. It is proved that the scheme is unconditionally stable with respect to the time variable in [Formula: see text] and convergent with the order of convergence [Formula: see text], [Formula: see text]. In this work, the thin plate splines (TPS) are used as the radial basis functions. In order to eliminate the nonlinearity, a simple predictor–corrector (P–C) scheme is used. The results of numerical experiments are compared to the analytical solutions in order to confirm the accuracy and the efficiency of the presented scheme.
Optimization of high-power Er/Yb co-doped fiber amplifiers for dual-band pulse amplification
Authors: Wang Juntao , Qi Yuanyuan , Lu Junchao , Li Xiaodong , Wang Junfei
Published: July 2018

In this paper, high-power pulse-pumped erbium–ytterbium co-doped fiber amplifiers (EYDFAs) for simultaneous amplification of low-repetition rate pulses in the 1.0 [Formula: see text]m and 1.5 [Formula: see text]m bands are numerically investigated. The influences of the peak power and pulse-width of the pump and time delay between the pump and signal pulses on the performance of the amplifier are systematically analyzed. The results show that a pulse-pumped EYDFA is capable of simultaneously amplifying dual-band pulses. The optimal pulse-width of the pump is mainly determined by the allowable power of the backward Yb amplified spontaneous emission (ASE). By simply adjusting the time delay between the pump and signal pulses, the power ratio of the dual-band signals can be easily changed. Such kind of dual-band-pulsed EYDFAs have great potential applications in fields such as the generation of visible or mid-infrared light by nonlinear frequency conversion, counter stealth Lidar, etc.
Numerical study of CdTe solar cells with p-MoTe2 TMDC as an interfacial layer using SCAPS
Authors: Moustafa Mohamed , Alzoubi Tariq
Published: July 2018

The impact of molybdenum ditelluride (p-type MoTe2) transition metal dichalcogenide (TMDC) material formation as an interfacial layer between CdTe absorber layer and Mo back contact is investigated. The simulation is conducted using the solar cell capacitance simulator (SCAPS) software. Band gap energy, carrier concentration, and layer thickness of the p-MoTe2 have been varied in this study to investigate the possible influences of p-MoTe2 on the electrical properties and the photovoltaic parameters of CdTe thin film solar cells. It has been observed that a thickness of the p-MoTe2 interfacial layer less than 60 nm leads to a decrease in the cell performance. In regard to the effect of the band gap, a maximum efficiency of 16.4% at the optimum energy gap value of 0.95 eV has been obtained at a doping of [Formula: see text]. Additionally, increasing the acceptor carrier concentration [Formula: see text] of MoTe2 enhances the solar cell performance. The solar cell efficiency reaches 15.5% with [Formula: see text] of [Formula: see text] with layer thicknesses above 80 nm. This might be attributed to the possibility of forming a back surface field for the photogenerated electrons, which reduces recombination at the back contact and hence provides a low resistivity contact for holes. The results justify that the MoTe2 interfacial layer mediates an ohmic contact to CdTe films.
Strong commutativity preserving maps of strictly triangular matrix Lie algebras
Authors: Chen Zhengxin , Liu Hongjin
Published: July 2018

Let [Formula: see text] be the Lie algebra consisting of all strictly upper triangular [Formula: see text] matrices over a field [Formula: see text]. An invertible linear map [Formula: see text] on [Formula: see text] is called to be strong commutativity preserving (simply denoted by SCP) if [Formula: see text] for any [Formula: see text]. We show that for [Formula: see text], an invertible linear map [Formula: see text] preserves strong commutativity if and only if there exist [Formula: see text] and a linear function [Formula: see text] with [Formula: see text] such that [Formula: see text], where [Formula: see text] is an inner SCP, [Formula: see text] are extremal SCPs, [Formula: see text] is a central SCP.
Deep learning in high dimension: Neural network expression rates for generalized polynomial chaos expansions in UQ
Authors: Schwab Christoph , Zech Jakob
Published: July 2018

We estimate the expressive power of certain deep neural networks (DNNs for short) on a class of countably-parametric, holomorphic maps [Formula: see text] on the parameter domain [Formula: see text]. Dimension-independent rates of best [Formula: see text]-term truncations of generalized polynomial chaos (gpc for short) approximations depend only on the summability exponent of the sequence of their gpc expansion coefficients. So-called [Formula: see text]-holomorphic maps [Formula: see text], with [Formula: see text] for some [Formula: see text], are known to allow gpc expansions with coefficient sequences in [Formula: see text]. Such maps arise for example as response surfaces of parametric PDEs, with applications in PDE uncertainty quantification (UQ) for many mathematical models in engineering and the sciences. Up to logarithmic terms, we establish the dimension independent approximation rate [Formula: see text] for these functions in terms of the total number [Formula: see text] of units and weights in the DNN. It follows that certain DNN architectures can overcome the curse of dimensionality when expressing possibly countably-parametric, real-valued maps with a certain degree of sparsity in the sequences of their gpc expansion coefficients. We also obtain rates of expressive power of DNNs for countably-parametric maps [Formula: see text], where [Formula: see text] is the Hilbert space [Formula: see text].
A nonsmooth static frictionless contact problem with locking materials
Authors: Sofonea Mircea
Published: July 2018

We study a new mathematical model which describes the equilibrium of a locking material in contact with a foundation. The contact is frictionless and is modeled with a nonsmooth multivalued interface law which involves unilateral constraints and subdifferential conditions. We describe the model and derive its weak formulation, which is in the form of an elliptic variational–hemivariational inequality for the displacement field. Then, we establish the existence of a unique weak solution to the problem. Next, we introduce a penalty method, for which we state and prove a convergence result. Finally, we consider a particular version of the model for which we prove the continuous dependence of the solution on the bounds which govern the locking and the normal displacement constraints, respectively. We apply this convergence result in the study of an optimization problem associated to the contact model.
Boundedness and compactness characterizations of Riesz transform commutators on Morrey spaces in the Bessel setting
Authors: Mao Suzhen , Wu Huoxiong , Yang Dongyong
Published: July 2018

Let [Formula: see text] and [Formula: see text] be the Bessel operator on [Formula: see text]. In this paper, the authors show that [Formula: see text] (or [Formula: see text], respectively) if and only if the Riesz transform commutator [Formula: see text] is bounded (or compact, respectively) on Morrey spaces [Formula: see text], where [Formula: see text], [Formula: see text] and [Formula: see text]. A weak factorization theorem for functions belonging to the Hardy space [Formula: see text] in the sense of Coifman–Rochberg–Weiss in Bessel setting, via [Formula: see text] and its adjoint, is also obtained.
Fusion-based image de-fogging using dual tree complex wavelet transform
Authors: Kansal Isha , Kasana Singara Singh
Published: July 2018

Images captured in foggy weather are severely degraded, which influences the tracking and recognition of objects present in those images. Therefore, restoring the true scene using a foggy image is important. In this paper, an effective fusion-based foggy image restoration technique by using dual tree complex wavelet transform (DT-CWT) has been proposed. Minimum color channel and the dark channel of a foggy image are constructed. Low and high pass components of both these channels are fused to obtain a transmission map. Dark channel is estimated by minimum preserving down sampling approach which improves the computational efficiency of the de-fogging process. Since DCP-based de-fogging techniques suffer from halo artifacts and darkness, proposed technique improves the overall contrast and the halo artifact regions in a time efficient way. To make the de-fogging results look uniformly bright, an adaptive post processing technique is applied on the de-fogged images. Comparative experiments with existing state-of-the-art algorithms show that de-fogging results of the proposed technique are better.
SAUDI ARABIAN WOMEN IN ENTREPRENEURSHIP: CHALLENGES, OPPORTUNITIES AND POTENTIAL
Authors: BASAFFAR AMAL A. , NIEHM LINDA S. , BOSSELMAN ROBERT
Published: July 2018

Although traditional cultural norms have tended to impede Saudi women’s engagement in entrepreneurship, there are successful female business owners in Saudi Arabia. The Saudi government, seeing female entrepreneurship as a way to strengthen both the family unit and the economy, has recently created programs to encourage more women to become business owners. However, few women have taken advantage of these programs to date. This study aimed to identify factors that enable female business owners to realize their entrepreneurial potential. Nine business-owning women were interviewed for this phenomenological study. Drawing on Kreuger and Brazeal’s Model of Entrepreneurial Potential (MEP), the study investigated Saudi female entrepreneurs’ perceived self-efficacy, perceived desirability, perceived feasibility and propensity to act on entrepreneurial opportunities. Currently, limited empirical research exists on women’s entrepreneurial activity in Saudi Arabia. This study sought to fill that gap. Results from this study revealed unique strategic approaches and business success factors from the perspective of Saudi women, including their ability to work within or around cultural norms and rules to operate their businesses. The study suggests ways in which Saudi society can support women in realizing their entrepreneurial potential and also makes policy recommendations for government and business support entities.
Some MoS2-based materials for sodium-ion battery
Authors: Li Qing , Guo Xiaotian , Zheng Mingbo , Pang Huan
Published: July 2018

Sodium-ion batteries (SIB) play a promising role in the area of energy storage device researching. MoS2-based materials are considered as one of the most attractive materials for high-performance SIBs owing to their high capacity, high cycle stability and excellent Coulomb effect. This review has summarized the synthesis of MoS2-based materials (MoS2, MoS2/carbon-based materials, MoS2/metal oxides, MoS2/metal sulfides) to emphasize their electrochemical behaviors in SIBs.
Efficient inverted planar perovskite solar cells based on inorganic hole-transport layers from nickel-containing organic sol
Authors: Zhang Weina , Tang Jie , Wu Jihuai , Lan Zhang
Published: July 2018

Due to the rough surface of fluorine-doped tin oxide (FTO) conductive glasses, it is challenging to fabricate fully covered ultra-thin hole-transport layer (HTL) with thickness under 100[Formula: see text]nm by a simple solution-processed method. Yet, the quality of HTLs play a key role in determining photovoltaic performance of the inverted planar perovskite solar cells (PSCs) owing to their important functions for effectively extracting holes, blocking electrons, suppressing dark reaction, and so on. Here, we report a facile nickel-containing organic sol (Ni–Sol) route to fabricate fully covered 46[Formula: see text]nm thick NiO HTLs for efficient inverted planar PSCs. Comparing with the pre-synthesized NiO nanocrystals solution, the Ni–Sol is easier to spread around the rough outline of FTO to achieve higher surface coverage. Through optimizing the concentration of nickel-containing organic sol, the champion performance of the inverted planar PSCs can be achieved because of the high transparency and good hole-transport dynamics of the optimized NiO film. This work demonstrates the advanced Ni–Sol route for preparing efficient inverted planar PSCs by the simple solution-processed method.
Octahedral distortion-driven electrical and vibrational properties of A2ErTaO6 (A=Sr and Ca) double perovskite oxides
Authors: Mukherjee Rajesh , Dutta Alo , Sinha T. P.
Published: July 2018

Rietveld refinement analysis indicates that [Formula: see text]ErTaO6 ([Formula: see text], Ca[Formula: see text] ceramics prepared by a solid-state route are crystallized in monoclinic perovskite phase with space group [Formula: see text]. Raman scattering and infrared spectroscopy are used to investigate the structure and phonon modes of the samples. Using Lorentzian lines, we have fitted the Raman spectra and the major Raman modes are assigned. Phonon vibrational frequency is modulated with the [Formula: see text]-site cationic change. Impedance spectra of the samples over the frequency range of 100[Formula: see text]Hz–1.1[Formula: see text]MHz are investigated at different temperatures from 303[Formula: see text]K to 573[Formula: see text]K. Cole–Cole relaxation of dielectric constant is modified with the electrical conduction parameter to describe the temperature dependence of dielectric constant. The frequency-dependent conductivity spectra follow the double power-law.
Free vibration analysis of Euler–Bernoulli nanobeam using differential transform method
Authors: Jena Subrat Kumar , Chakraverty S.
Published: July 2018

In this paper, a semi analytical-numerical technique called differential transform method (DTM) is applied to investigate free vibration of nanobeams based on non-local Euler–Bernoulli beam theory. The essential steps of the DTM application include transforming the governing equations of motion into algebraic equations, solving the transformed equations and then applying a process of inverse transformation to obtain accurate mode frequency. All the steps of the DTM are very straightforward, and the application of the DTM to both the equations of motion and the boundary conditions seems to be very involved computationally. Besides all these, the analysis of the convergence of the results shows that DTM solutions converge fast. In this paper, a detailed investigation has been reported and MATLAB code has been developed to analyze the numerical results for different scaling parameters as well as for four types of boundary conditions. Present results are compared with other available results and are found to be in good agreement.
Theoretical Investigation on Cross-Coupling Effect of Two-Dimensional Compound Pendulum Tiltmeter
Authors: Wu Lihua , Huang Yu
Published: July 2018

The active vibration isolation of low-frequency tilt is important for precise scientific measurement. However, the cross-coupling effects in tilt sensitive probes introduce negative effects on the performance of active isolation devices. In this paper, we show the structure and basic principle of compound pendulum (CP)-type tiltmeter, and analyze the dynamic response of the CP to the two-dimensional tilt vibrations. Besides, we deduce theoretically the mathematical model of the capacitive sensing of the displacements of the CP. Finally, we evaluate numerically the cross-coupling effects of a tilt sensitive probe including the cross-couplings of dynamic response and the different capacitance variations in two orthogonal degrees of freedoms. The maximum of the mechanical dynamic coupling factor is less than −60[Formula: see text]dB. The total cross-coupling coefficients including the different capacitance variations of the probe are both less than [Formula: see text]. Therefore, the cross-coupling effects don’t have to be considered for this kind of two-dimensional tilt sensitive probe.