bluuebunny/crossref_metadata_2025 huggingface dataset:
Global pattern of short‐term concurrent hot and dry extremes and its relationship to large‐scale climate indices
Authors: Zhang Haoyue , Wu Chuanhao , Yeh Pat J.‐F. , Hu Bill X.
Published: March 2020

The short‐term concurrent hot and dry extreme (SCHDE) event has recently stimulated intensive scientific interests due to its rapid onset, severe intensity, and devastating impacts on agriculture and natural ecosystems. The SCHDE is mainly caused by an increase in actual evapotranspiration (ET) accompanied with a decrease in soil moisture (SM) due to anomalously high surface temperature (Tair). Based on the daily datasets of precipitation (P), Tair, ET, and SM from four global modelling products as well as large‐scale climate indices, we analyse globally the spatio‐temporal evolution of SCHDE events at both grid and basin scales. Results indicate that SCHDE events occur mostly in Northern Hemisphere regions with relatively low P. During 1980–2010, due to significant global warming (0.30°C·decade−1) the global mean occurrence frequency of SCHDE has an increasing trend (0.34%·decade−1) along with a weakly decreasing trend of SM (~−0.08%·decade−1) and a significantly increasing trend of ET (~8.34 mm·decade−1). Overall, North America and Asia have a higher frequency of SCHDE occurrence than other continents. The variability of Tair is mainly responsible for the variability of SCHDE occurrence over the equator regions, while the variability of ET (SM) plays an important role in SCHDE occurrence variability in the cropland‐dominant (mid‐ and high‐latitude) regions. Globally, the relative contribution of Tair to SCHDE variability is the largest, followed by ET and SM. Lastly, we found that the cold phases of the Pacific Decadal Oscillation during the La Niña events (i.e., negative Multivariate ENSO Index) are conducive to the intensification of SCHDE events in southern South America and Australia.
Athletes after anterior cruciate ligament reconstruction demonstrate asymmetric intracortical facilitation early after surgery
Authors: Zarzycki Ryan , Morton Susanne M. , Charalambous Charalambos C. , Pietrosimone Brian , Williams Glenn N. , Snyder‐Mackler Lynn
Published: March 2020

Quadriceps dysfunction persists after anterior cruciate ligament reconstruction (ACLR), yet the etiology remains elusive. Inhibitory and facilitatory intracortical networks (ie, intracortical excitability) may be involved in quadriceps dysfunction, yet the investigation of these networks early after ACLR is sparse. The purposes of this study were to examine (a) changes in intracortical excitability in athletes after ACLR compared to uninjured athletes during the course of postoperative rehabilitation, (b) the association between intracortical excitability and quadriceps strength in athletes after ACLR. Eighteen level I/II athletes after ACLR between the ages of 18 to 30 years and eighteen healthy sex, age, and activity matched athletes were tested at three‐time points: (a) 2 weeks after surgery, (b) achievement of a “quiet knee” defined as full range of motion and minimal effusion, (c) return to running time point defined as achievement of a quadriceps index ≥80% and at least 12 weeks post‐ACLR. Short‐interval intracortical inhibition (SICI) and intracortical facilitation (ICF), measured via transcranial magnetic stimulation and isometric quadriceps strength were examined bilaterally at each time point. There was a significant group × limb interaction (P = .017) for ICF. The ACLR group demonstrated asymmetric ICF (greater in the nonsurgical limb) compared to controls and a significant relationship between SICI and quadriceps strength of the surgical limb at the quiet knee time point (P = .018). ACLR individuals demonstrate differential effects on ICF between limbs. Also, SICI is associated with isometric quadriceps strength after ACLR, suggesting increased inhibition of the motor cortex may contribute to impaired quadriceps strength following ACLR.
Nutrition Support Teams: A Systematic Review
Authors: Mistiaen Patriek , Van den Heede Koen
Published: March 2020

Background

The concept of a nutrition support team (NST) was first introduced at the end of the 20th century in the US and Europe. Expected benefits include reduced (inappropriate) prescription of (par)enteral nutrition; however, to the authors’ knowledge, no recent review has assessed the effectiveness of NSTs. Therefore, this systematic review evaluated the effectiveness of NSTs with respect to the prevalence of adult patients receiving (par)enteral nutrition.

Methods

Five literature databases were searched and completed by citing searches. Studies on NSTs that were published between 2000 and 2018 in Western countries, applied a comparative design, and contained at least outcome data on the prevalence of (par)enteral nutrition were included. Analyses were mainly descriptive because of high heterogeneity that prevented meta‐analyses.

Results

The 27 included studies mainly originated from the UK and US. Only 1 of the included studies was a randomized trial; the other studies had a pre‐post design (n = 17) or compared groups in a nonrandomized way. All but 2 studies were performed in acute care hospitals, and 5 studies focused only on intensive care patients. There was conflicting evidence of whether NSTs lead to reduction or increase in patients starting parenteral nutrition (PN); however, weak evidence suggested that NSTs might lead to an increase in the ratio of enteral nutrition to PN use and might decrease inappropriate PN use.

Conclusion

Although almost all studies concluded in favor of NSTs, the evidence base is weak and insufficient because of a lack of well‐designed studies and successful outcomes.
Migrant identity and subsequent travel behaviour
Authors: Yankholmes Aaron , McKercher Bob
Published: March 2020

This study assesses whether changes in migrants' identity predict changes in their travel behaviour. Data were collected from Western professional migrants in Hong Kong and Macau using open‐ended self‐completed survey questions. Results derived from content analysis indicate that long‐term migrants benefit from greater accessibility to many regional destinations, home‐return trips, and lower fares while temporary migrants and those on contracts felt constrained to pursue pleasure travel. Factors explaining tourism‐oriented motives to move comprise convenient hub, rite of passage, continuation of identity, and career maintenance. Many reasons are also found to account for changes in travel frequency and destination choice over time. These findings can shape marketing actions for destinations in the region as well as provide a platform for future theoretical and empirical research on the relationship between tourism and migration.
Corrosion decomposition and mechanical behaviors of As‐cast Mg–xZn–Zr alloys
Authors: Li Xuewu , Zhou Longlong , Shi Tian , Li Ben , Yu Weining , Zhang Chuanwei , Yan Pan , Zhang Qiaoxin , Tian Haoliang , Lv Yuan
Published: March 2020

Developing new‐type alloy materials with excellent decomposition properties and mechanical behaviors is a thorny issue for preparing fracturing balls in oil exploitation. As‐cast Mg–xZn–Zr alloys designed by regulating Zn contents have been fabricated in this study. Compressive strength and immersion corrosion test have been investigated to assess their feasibility as decomposition materials. Scanning electron microscopy and X‐ray diffract meter have also been used to characterize surface morphologies and phase structures for determining their decomposition mechanism. Results show that matrix phases and secondary phases with discontinuous reticular features form on the alloys. They also achieve excellent mechanical properties to ensure stability and pressure‐maintaining capacity in the decomposition process in chloride environment. Meanwhile, with Zn content and immersion time increasing, galvanic corrosion effect strengthens leading to accelerated specific mass loss rates of the alloys. Rapid corrosion decomposition of the alloys mainly attributes to anodic dissolution of matrix phases, exfoliation of microparticles, and poor resistance of corrosion products to the decomposition process. This study provides positive insight into the preparation of new‐type Mg alloys for guaranteeing fast decomposition of fracturing balls and also ensuring their compressive strength stability.
Development and characterization of β‐type Ti‐Zr‐Nb‐Sn dental implant materials
Authors: Dang Z. , Zhan Y.
Published: March 2020

To develop new materials of proper elastic modulus and biocompatibility for dental implants, Ti‐2Zr‐xNb‐xSn (x = 0, 0.1, 0.2, 0.3) and Ti‐2Zr‐xNb‐xMo (x = 0, 0.1, 0.2, 0.3) alloys were designed and fabricated. Effects of alloying elements on properties and the feasibility of application in dentistry are analyzed. It is indicated that Nb, Sn and Mo obviously influence the phase compositions of Ti‐2Zr‐based biological alloys. With the increase of alloying element content, all the alloys tend to form a single β‐Ti phase. Ti‐2Zr‐xNb‐xSn alloys exhibit better mechanical properties and corrosion resistance than the Ti‐2Zr‐xNb‐xMo alloys. The Ti‐2Zr‐0.1Nb‐0.1Sn alloy has proper elastic modulus (14.72 GPa) (which is very close to the natural bones), excellent corrosion resistance and comprehensive mechanical properties, and is considered as ideal candidate for implant materials.
Effect of heat input and weld chemistry on mechanical and microstructural aspects of double side welded austenitic stainless steel 321 grade using tungsten inert gas arc welding process
Authors: Mohan Kumar S. , Siva Shanmugam N.
Published: March 2020

Stainless steel 321 is a stabilized austenitic grade that prevents the formation of chromium carbides at the grain boundaries and subsequently reduces the risk of corrosion attack at the weld surface by forming titanium carbide. It is primarily used in industries such as pressure vessels, boilers, nuclear reactors, carburetors and car exhaust systems. In order to assess the effect of gas tungsten arc welding process parameters on weld penetration, the proposed Taguchi L9 orthogonal matrix has been selected with two factors and three levels for welding austenitic stainless steel 321 by adjusting the welding current and welding speed. Bead‐on‐plate experiments were performed on base metal of 6 mm thick plate by changing the process parameters, and corresponding weld bead measurement and macrostructure images are examined. Maximum depth of penetration −3.3017 mm is achieved with a heat input −1.4058 kJ/mm, i. e., welding current‐220 A and welding speed‐120 mm/min. Double‐side arc welding technique is used to obtain full penetration on 6 mm thick plate. The quality of the weldment was assessed using non‐destructive radiography inspection. Mechanical integrity and microstructural characteristics of the weldments were studied using tensile (transverse and longitudinal), bend, impact, microhardness, optical microscopy, energy dispersive x‐ray spectroscopy, x‐ray diffraction analysis, ferrite number measurement and scanning electron microscope. The results reveal that the double side‐tungsten inert gas weldment have better mechanical properties. It is corroborated from the weld metal microstructure that it contains γ‐austenite, δ‐ferrite and titanium carbides (intermetallic compounds). X‐ray diffraction analysis and energy dispersive x‐ray spectroscopy plots confirm the increase in the ferrite phase in weld metal. The ferrite measurement results show that the ferrite volume in the base metal and weld metal is 1.2 percent and 6.1 percent respectively. In addition, the higher δ‐ferrite volume in the weldment helps in attaining superior mechanical integrity. Fractography shows that the failure mode of the weld metal and the base metal is ductile.
On the fatigue and fracture behavior of necked double shear lugs for aircraft applications
Authors: Winklberger M. , Schagerl M.
Published: March 2020

The fatigue and fracture behavior of double shear lugs subjected to axial loading is investigated. The focus is on specific shapes, so‐called waisted or necked lugs. These structural components used in aircraft interior are prone to fatigue loads. Three different sizes of necked double shear lugs made of high strength aluminum 2024‐T351 and steel 17–4 PH are tested using constant amplitude cyclic loadings with a load ratio R = 0.01. Measurement data is used to identify the number of cycles to crack initiation and final fracture. Fatigue tests show that cracks initiate either at the inside or outside surface of necked lugs. However, no clear dependency on the load amplitude, lug size and material could be found. Numerical simulations using both conventional finite element method (FEM) and extended finite element method (XFEM) are performed to calculate the stress intensity factors (SIFs) for multiple crack lengths of straight and necked double shear lugs. Calculated stress intensity factors for straight lugs fit well to stress intensity factors reported in literature. Stress intensity factor curves of inside and outside cracks of necked lugs plotted with respect to crack length, cross each other, which could have an influence on the fracture behavior observed in fatigue tests.
Geographical separation and physiology drive differentiation of microbial communities of two discrete populations of the bat Leptonycteris yerbabuenae
Authors: Gaona Osiris , Cerqueda‐García Daniel , Moya Andrés , Neri‐Barrios Ximena , Falcón Luisa I.
Published: March 2020

In this paper, we explore how two discrete and geographically separated populations of the lesser long‐nosed bat (Leptonycteris yerbabuenae)—one in central and the other in the Pacific region of Mexico—differ in their fecal microbiota composition. Considering the microbiota–host as a unity, in which extrinsic (as food availability and geography) or intrinsic factors (as physiology) play an important role in the microbiota composition, we would expect differentiation in the microbiota of two geographically separated populations. The Amplicon Sequences Variants (ASVs) of the V4 region of the 16s rRNA gene from 68 individuals were analyzed using alpha and beta diversity metrics. We obtained a total of 11 566 (ASVs). The bacterial communities in the Central and Pacific populations had a diversity of 6,939 and 4,088 ASVs, respectively, sharing a core microbiota of 539 ASVs accounting for 75% of the relative abundance, suggesting stability over evolutionary time. The Weighted UniFrac metrics tested by a PERMANOVA showed that lactating and pregnant females had significant beta diversity differences in the two populations compared with other reproductive stages. This could be a consequence of the increased energy requirements of these physiological stages, more than the variation due to geographical separation. In contrast, a positive correlation of the observed ASVs of fecal microbiota with the observed ASVs of plastids related to the diet was observed in the juveniles and adults, suggesting that in these physiological stages an extrinsic factor as the diet shapes the microbiota composition. The results provide a baseline for future studies of the microbiome in these two wild populations of the lesser long‐nosed bat, the main pollinator of the Agaves from which the beverages tequila and mezcal are made.
MRI of Motor and Nonmotor Therapy‐Induced Complications in Parkinson's Disease
Authors: Donzuso Giulia , Agosta Federica , Canu Elisa , Filippi Massimo
Published: March 2020

Levodopa therapy remains the most effective drug for the treatment of Parkinson's disease, and it is associated with the greatest improvement in motor function as assessed by the Unified Parkinson's Disease Rating Scale. Dopamine agonists have also proven their efficacy as monotherapy in early Parkinson's disease but also as adjunct therapy. However, the chronic use of dopaminergic therapy is associated with disabling motor and nonmotor side effects and complications, among which levodopa‐induced dyskinesias and impulse control behaviors are the most common. The underlying mechanisms of these disorders are not fully understood. In the last decade, classic neuroimaging methods and more sophisticated techniques, such as analysis of gray‐matter structural imaging and functional magnetic resonance imaging, have given access to anatomical and functional abnormalities, respectively, in the brain. This review presents an overview of structural and functional brain changes associated with motor and nonmotor therapy‐induced complications in Parkinson's disease. Magnetic resonance imaging may offer structural and/or functional neuroimaging biomarkers that could be used as predictive signs of development, maintenance, and progression of these complications. Neurophysiological tools, such as theta burst stimulation and transcranial magnetic stimulation, might help us to integrate neuroimaging findings and clinical features and could be used as therapeutic options, translating neuroimaging data into clinical practice. © 2020 International Parkinson and Movement Disorder Society
Identification of key genes and pathways of diagnosis and prognosis in cervical cancer by bioinformatics analysis
Authors: Yang Hua‐ju , Xue Jin‐min , Li Jie , Wan Ling‐hong , Zhu Yu‐xi
Published: March 2020

Background

Cervical cancer as one of the most common malignant tumors lead to bad prognosis among women. Some researches already focus on the carcinogenesis and pathogenesis of cervical cancer, but it is still necessary to identify more key genes and pathways.

Methods

Differentially expressed genes were identified by GEO2R from the gene expression omnibus (GEO) website, then gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyzed by DAVID. Meanwhile, protein–protein interaction network was constructed by STRING, and both key genes and modules were found in visualizing network through Cytoscape. Besides, GEPIA did the differential expression of key genes and survival analysis. Finally, the expression of genes related to prognosis was further explored by UNLCAN, oncomine, and the human protein atlas.

Results

Totally 57 differentially expressed genes were founded, not only enriched in G1/S transition of mitotic cell cycle, mitotic nuclear division, and cell division but also participated in cytokine–cytokine receptor interaction, toll‐like receptor signaling pathway, and amoebiasis. Additionally, 12 hub genes and 3 key modules were screened in the Cytoscape visualization network. Further survival analysis showed that TYMS (OMIM accession number 188350), MCM2 (OMIM accession number 116945), HELLS (OMIM accession number 603946), TOP2A (OMIM accession number 126430), and CXCL8 (OMIM accession number 146930) were associated with the prognosis of cervical cancer.

Conclusion

This study aim to better understand the characteristics of some genes and signaling pathways about cervical cancer by bioinformatics, and could provide further research ideas to find new mechanism, more prognostic factors, and potential therapeutic targets for cervical cancer.
Global analysis of a diffusive viral model with cell‐to‐cell infection and incubation period
Authors: Wang Wei , Wang Xiunan , Guo Ke , Ma Wanbiao
Published: March 2020

We propose a diffusive viral model incorporating cell‐to‐cell infection mode, nonlinear incidences, incubation period, and spatial heterogeneity. For the spatially heterogeneous model, we derive the extinction/persistence result by the basic reproduction number
. For the spatially homogeneous model, we study global stabilities of steady states by establishing Lyapunov functions. The existing method for studying global stabilities of diffusive viral models has been generalized, which weakens the required conditions. Some existing results can be covered and improved. A specific example is given to illustrate the general results. In addition, we show that
is underestimated if we neglect incubation period of infected cells.
A note on the modified Picard integral operators
Authors: Yılmaz Başar , Aydın Arı Didem
Published: March 2020

This study is a natural continuation of modified Picard operators, defined by Agratini et al, preserving an exponential function. Herein, we first show that these operators are approximation processes in the setting of large classes of weighted spaces. Then, we obtain weighted uniform convergence of the operators via exponential weighted modulus of smoothness. Finally, we give, by using the weighted modulus of continuity, the result regarding global smoothness preservation properties for the generalized Picard operators, which based in Agratini et al.
Pricing and capacity allocation strategies: Implications for manufacturers with product sharing
Authors: Dai Bin , Nu Yu
Published: March 2020

Emerging sharing modes, like the consumer‐to‐consumer (C2C) sharing of Uber and the business‐to‐consumer (B2C) sharing of GoFun, have considerably affected the retailing markets of traditional manufacturers, who are motivated to consider product sharing when making pricing and capacity decisions, particularly electric car manufacturers with limited capacity. In this paper, we examine the equilibrium pricing for a capacity‐constrained manufacturer under various sharing modes and further analyze the impact of capacity constraint on the manufacturer's sharing mode selection as well as equilibrium outcomes. We find that manufacturers with low‐cost products prefer B2C sharing while those with high‐cost products prefer C2C sharing except when the sharing price is moderate. However, limited capacity motivates manufacturers to enter into the B2C sharing under a relatively low sharing price, and raise the total usage level by sharing high‐cost products. We also show that the equilibrium capacity allocated to the sharing market with low‐cost products first increases and then decreases. Finally, we find that sharing low‐cost products with a high limited capacity leads to a lower retail price under B2C sharing, which creates a win‐win situation for both the manufacturer and consumers. However, sharing high‐cost products with a low limited capacity creates a win‐lose situation for
them.
Callable products with dependent demands
Authors: Gallego Guillermo , Lee Haengju
Published: March 2020

Capacity providers such as airlines often sell the same capacity to different market segments at different prices to improve their expected revenues. The absence of a secondary market, due to the nontransferability of airline tickets, gives rise to an opportunity for airlines to broker capacity between consumers with different willingness to pay. One way to broker capacity is by the introduction of callable products. The idea is similar to callable bonds where the issuer has the right, but not the obligation, to buy back the bonds at a certain price by a certain date. The idea of callable products was introduced before under the assumption that the fare‐class demands are all independent. The independent assumption becomes untenable when there is significant demand recovery (respectively, demand cannibalization) when lower fares are closed (respectively, opened). In this case, consumer choice behavior should be modeled explicitly to make meaningful decisions. In this paper, we consider a general consumer choice model and develop the optimal strategy for callable products. Our numerical study illustrates how callable products are win‐win‐win, for the capacity provider and for both high and low fare consumers. Our studies also identify conditions for callable products to result in significant improvements in expected revenues.
Numerical study in stochastic homogenization for elliptic partial differential equations: Convergence rate in the size of representative volume elements
Authors: Khoromskaia Venera , Khoromskij Boris N. , Otto Felix
Published: March 2020

We describe the numerical scheme for the discretization and solution of 2D elliptic equations with strongly varying piecewise constant coefficients arising in the stochastic homogenization of multiscale composite materials. An efficient stiffness matrix generation scheme based on assembling the local Kronecker product matrices is introduced. The resulting large linear systems of equations are solved by the preconditioned conjugate gradient iteration with a convergence rate that is independent of the grid size and the variation in jumping coefficients (contrast). Using this solver, we numerically investigate the convergence of the representative volume element (RVE) method in stochastic homogenization that extracts the effective behavior of the random coefficient field. Our numerical experiments confirm the asymptotic convergence rate of systematic error and standard deviation in the size of RVE rigorously established in Gloria et al. The asymptotic behavior of covariances of the homogenized matrix in the form of a quartic tensor is also studied numerically. Our approach allows laptop computation of sufficiently large number of stochastic realizations even for large sizes of the
RVE.
Highly efficient flame retardant poly(lactic acid) using imidazole phosphate poly(ionic liquid)
Authors: Li Caixia , Ma Chao , Li Juan
Published: March 2020

Because of good thermal stability, nonflammability and rich structural designability, ionic liquids (ILs) have been used as flame retardants for poly(lactic acid) (PLA). However, as a small molecule, IL has the disadvantages of poor thermal stability and water resistance, and so on. In this paper, an imidazole‐type poly(ionic liquid) (PIL) containing a phosphate anion was synthesized using 1‐vinylimidazole, triethyl phosphate, and 1,2‐divinylbenzene and marked as PDVE[DEP]. The PDVE[DEP] was used to improve the flame retardancy of PLA. The flame retardancy and thermal degradation behaviors of PLA/PDVE[DEP] composites were investigated by the limited oxygen index (LOI), UL‐94 vertical burning, cone calorimetry, and thermal gravity analysis, and so on. The results showed that only 1.0 wt% PDVE[DEP] allows PLA to achieve the UL‐94 V0 rating and obtain LOI value 25.6 vol%. The PDVE[DEP] improve the flame retardancy of PLA by melting‐away mode. In addition, it catalyzes the transesterification of PLA and changes the degradation products.
Small‐scale analysis of phytoecdysteroids in seeds by HPLC‐DAD‐MS for the identification and quantification of specific analogues, dereplication and chemotaxonomy
Authors: Dinan Laurence , Balducci Christine , Guibout Louis , Lafont René
Published: March 2020

Introduction

Phytoecdysteroids are analogues of arthropod steroids occurring in plants. They contribute to invertebrate deterrence. A wide diversity of ecdysteroids occurs in phytoecdysteroid‐containing plant species, sometimes in high amounts. Ecdysteroids demonstrate potentially useful pharmaceutical actions in mammals.

Objectives

Establish reversed‐phase high‐performance liquid chromatography with tandem mass spectrometry (RP‐HPLC‐MS/MS) and RP‐HPLC‐DAD‐MS (diode array detector mass spectrometry) methods for the separation, identification and quantification of ecdysteroids to screen for species containing significant amounts of 20‐hydroxyecdysone (20E) and other useful ecdysteroids.

Materials and methods

Micro‐extracts of seed samples (ca. 30 mg) in 50% ethanol were subjected to RP‐SPE (solid‐phase extraction) purification prior to analysis by RP‐HPLC‐MS/MS and RP‐HPLC‐DAD‐MS.

The method was initially applied to genera (Amaranthus, Centaurea, Lychnis, Ourisia, Serratula, Silene and Trollius) where high‐accumulating species had been previously encountered. Seeds of 160 randomly selected species, many of which have not previously been assessed, were then analysed. HPLC‐MS/MS with a short analysis time initially identifies ecdysteroid‐positive extracts and quantifies 20E. The positive extracts (20 ng 20E) are then analysed by HPLC‐MS/MS with a longer analysis time to identify and quantify 17 common phytoecdysteroids and, finally, HPLC‐DAD‐MS (0.1–0.25 μg 20E) is used to obtain UV‐ and MS‐spectra to confirm identifications or as a basis for characterisation of partially identified or novel analogues.

Results

Lychnis coronaria, Silene fimbriata and Silene hookeri ecdysteroids are characterised for the first time and those of Cucubalus baccifer and Ipheion uniflorum are more extensively characterised.

Conclusions

The procedure provides a rapid/sensitive method for screening small plant samples for the presence, quantification and identification of ecdysteroids. It permits ready dereplication of samples, identifying extracts containing large amounts or novel analogues.
Neutropenic enterocolitis in pediatric leukemia patients treated with intensive chemotherapy in Upper Egypt
Authors: Fouad Ereen Refaat , Morsy Ahmed Mohammed , Kamel Hosam Eldein Mostafa , Ali Amany Mohamed
Published: March 2020

Importance

In low resource countries, there has been scarcity of research on the risk factors associated with neutropenic enterocolitis, a serious complication that commonly develops during treatment of cancer patients.

Objective

To identify the pattern of intestinal complications in pediatric leukemia patients treated with intensive chemotherapy, including those with neutropenic enterocolitis; to assess the outcome; and to evaluate the risk factors associated with the mortality in these patients.

Methods

During the period from June 2015 to December 2016, a prospective study was carried out on pediatric patients diagnosed with acute leukemia who received induction/or re‐induction phases of chemotherapy at South Egypt Cancer Institute. Patients with documented episodes of intestinal complications were included in the study. Recovery or death from an episode of intestinal complication was utilized as the primary outcome measure for the study. Using univariable and multivariable methods, potential risk factors associated with mortality were delineated by logistic regression analysis, both for the entire intestinal complications episodes as a whole and for those episodes of neutropenic enterocolitis only.

Results

Out of 88 documented episodes of intestinal complications from 77 patients; 58 episodes were identified as neutropenic enterocolitis from 47 patients. In those patients who were having episodes of neutropenic enterocolitis, the presence of abdominal tenderness (OR 4.529, 95%CI 1.062–19.317, P = 0.041); a longer duration of neutropenia (OR 1.215, 95%CI 1.030–1.434, P = 0.021); and hemodynamic instability (OR 17.023, 95%CI 4.095–70.772, P < 0.001), were found to be independently associated with worse outcome.

Interpretation

In Upper Egypt, the use of intensive systemic chemotherapy during the induction phase of acute leukemia was found to be associated with potentially lethal intestinal complications. A high index of clinical suspicion is warranted.
Developing academic talent as a practicing school psychologist: From potential to expertise
Authors: Dixson Dante D. , Olszewski‐Kubilius Paula , Subotnik Rena F. , Worrell Frank C.
Published: March 2020

In this article, we explore how school psychologists who adopt a talent development perspective can play a larger role in cultivating the talent of academically gifted students. Utilizing the talent development megamodel and Ackerman's model of expertise, we outline how school psychologists can consult with school administrators, teachers, and parents to meet the general and domain‐specific academic needs of academically gifted students at home and in school. In addition, we discuss how school psychologists can leverage systems of assessment (e.g., universal screening, continued assessment) to identify academically gifted students across academic talent trajectories as well as provide students with multiple opportunities to exhibit their academic talents. We conclude by highlighting some diversity and multi‐cultural considerations that school psychologists should keep in mind while developing academic talent, as well as a policy implication of school psychologists adopting a talent development approach to their work.
Structural studies on 10‐hydroxygeraniol dehydrogenase: A novel linear substrate‐specific dehydrogenase from Catharanthus roseus
Authors: Sandholu Anand S. , Mujawar Sharmila P. , Ramakrishnan Krithika , Thulasiram Hirekodathakallu V. , Kulkarni Kiran
Published: March 2020

Conversion of 10‐hydroxygeraniol to 10‐oxogeranial is a crucial step in iridoid biosynthesis. This reaction is catalyzed by a zinc‐dependent alcohol dehydrogenase, 10‐hydroxygeraniol dehydrogenase, belonging to the family of medium‐chain dehydrogenase/reductase (MDR). Here, we report the crystal structures of a novel 10‐hydroxygeraniol dehydrogenase from Catharanthus roseus in its apo and nicotinamide adenine dinucleotide phosphate (NADP+) bound forms. Structural analysis and docking studies reveal how subtle conformational differences of loops L1, L2, L3, and helix α9' at the orifice of the catalytic site confer differential activity of the enzyme toward various substrates, by modulating the binding pocket shape and volume. The present study, first of its kind, provides insights into the structural basis of substrate specificity of MDRs specific to linear substrates. Furthermore, comparison of apo and NADP+ bound structures suggests that the enzyme adopts open and closed states to facilitate cofactor binding.
Investigation of structural, elastic, thermophysical, magneto‐electronic, and transport properties of newly tailored Mn‐based Heuslers: A density functional theory study
Authors: Sofi Shakeel Ahmad , Gupta Dinesh C.
Published: March 2020

Self‐consistent ab‐initio calculations with highly precise spin‐polarized, density functional theory have been performed for the first time, to investigate the electronic structure, magnetism, transport, elasto‐mechanical, and thermophysical properties of newly tailored Mn‐based full‐Heuslers. The cohesive and ground‐state energy calculations in ferromagnetic, nonmagnetic, and antiferromagnetic states confirm the stability of materials in face‐centered ferromagnetic configuration. The spin‐based band structure analysis is well defined by modified Becke‐Johnson potential with the occurrence of half‐metallic character along the Fermi level. Estimation of elastic parameters is used to check the mechanical stability and nature of forces occurring in materials, where we see the alloys display ductile nature along with a Debye temperature of 398.75 K for Mn2NbAl, 337.53 K for Mn2NbGa, and 360.52 K for Mn2NbIn. Furthermore, within the solution of Boltzmann theory, thermoelectric efficient parameters address its applications in energy harvesting and solid‐state device applications. Thermodynamic potentials have been keenly predicted by implementing quasi harmonic Debye model to descript its stability at high temperature and pressure varying conditions. The prediction of ground state and thermodynamic properties from extensive first‐principles calculations could be beneficial for its future experimental insights with intriguing applications. Hence, the overall theme from the current study creates an application stand in spintronics, power generation, as well as green energy sources for future technologies.
Terminal location method with NLOS exclusion based on unsupervised learning in 5G‐LEO satellite communication systems
Authors: Zhu Feng , Ba Teer , Zhang Yuan , Gao Xiqi , Wang Jiang
Published: March 2020

We investigate the terminal location method in 5G‐Low Earth Orbit (5G‐LEO) satellite communication systems. To overcome the dependence on the external Global Navigation Satellite System (GNSS), we propose to use a single LEO satellite in 5G‐LEO satellite communication systems for terminal location and utilize the downlink synchronization detection for pseudorange differential measurement. Then, a data clustering method of unsupervised machine learning is proposed to classify the measured data into line‐of‐sight (LOS) and non‐line‐of‐sight (NLOS) signals. Furthermore, the NLOS data are excluded, and the Taylor series expansion iteration method is used to calculate the terminal coordinates. Simulation results show that the proposed method can effectively reduce the influence of NLOS error on measurement results and improve the accuracy of terminal location. In simulated urban scenario, the average location accuracy is improved from 10 km by traditional methods to 0.7 km and the convergence time is reduced from 400 to 250s.
Probing the Interaction of Nucleobases and Fluorophore‐Tagged Nucleobases with Graphene Surface: Adsorption and Fluorescence Studies
Authors: Bhai Surjit , Ganguly Bishwajit
Published: March 2020

Adsorption of a fluorophore‐labeled DNA oligonucleotide by graphene nano‐probes is of interest to exploit as bio‐sensing material. This work reports the fluorescence properties of fluorophore tagged nucleobases on the graphene surface computationally. The interaction of nucleobases and fluorophore tagged nucleobases to the graphene surface examined using M062X/6‐31G(d) level of theory in the gas phase and ethanol solvent. The binding energies of nucleobases on the graphene surface in the gas phase follows the order: G>A≥C≥T in agreement with the previous reports. The slab model calculations performed with LDA/PWC/DND level of theory also revealed a similar binding affinity on the graphene surface in the gas phase. The fluorescence of benzoxazole as fluorophore tagged with nucleobase on graphene surface was investigated using TD‐DFT M06‐2X/6‐31G(d) level of theory. The binding preference of the fluorophore tagged nucleobases is not significantly different in ethanol solvent. The aromaticity of the nucleobases tagged fluorophore on the graphene surface was investigated by NICS (1) and NICS (1)zz calculations and the aromaticity was found to be increased upon interaction with the graphene surface. The fluorescence quenching upon binding of fluorophore tagged nucleobases on graphene surface revealed the importance of purine nucleobases and found to be more prominent with guanine tagged fluorophore.
Multidimension‐Controllable Synthesis of MOF‐Derived Co@N‐Doped Carbon Composite with Magnetic‐Dielectric Synergy toward Strong Microwave Absorption
Authors: Huang Mengqiu , Wang Lei , Pei Ke , You Wenbin , Yu Xuefeng , Wu Zhengchen , Che Renchao
Published: March 2020

Metal–organic framework (MOF) is highly desirable as a functional material owing to its low density, tunable pore size, and diversity of coordination formation, but limited by the poor dielectric properties. Herein, by controlling the solvent and mole ratio of cobalt/linker, multidimension‐controllable MOF‐derived nitrogen‐doped carbon materials exhibit tunable morphology from sheet‐, flower‐, cube‐, dodecahedron‐ to octahedron‐like. Tunable electromagnetic parameters of Co@N‐doped carbon composites (Co@NC) can be obtained and the initial MOF precursor determines the distribution of carbon framework and magnetic cobalt nanoparticles. Carbonized Co@NC composites possess the following advantages: i) controllable dimension and morphology to balance the electromagnetic properties with evenly charged density distribution; ii) magnetic‐carbon composites offer plenty of interfacial polarization and strong magnetic coupling network; iii) a MOF‐derived dielectric carbon skeleton provides electronic transportation paths and enhances conductive dissipation. Surface‐mediated magnetic coupling reflects the stray magnetic flux field, which is corroborated by the off‐axis electron holography and micro‐magnetic simulation. Optimized octadecahedral Co@NC sample exhibits the best microwave absorption (MA) of −53.0 dB at the thickness of 1.8 mm and broad effective frequency from 11.4 to 17.6 GHz (Ku‐band). These results pave the way to fabricate high‐performance MA materials with balanced electromagnetic distribution and controlled morphology.
Automated testing in robotic process automation projects
Authors: Jiménez‐Ramírez Andres , Chacón‐Montero Jesús , Wojdynsky Tomasz , González Enríquez José
Published: March 2020

Robotic process automation (RPA) has received increasing attention in recent years. It enables task automation by software components, which interact with user interfaces in a similar way to that of humans. An RPA project life cycle is closely resembling a software project one. However, in certain contexts (e.g., business process outsourcing), a testing environment is not always available. Thus, deploying the robots in the production environment entails high risk. To mitigate it, an innovative approach to automatically generate a testing environment and a test suite for an RPA project is presented. The activities of the humans whose processes are to be robotized are monitored and a UI log is confirmed. On one side, the test environment is generated as a fake application, which mimics the real environment by leveraging the UI log information. The control flow of the application is governed by an invisible control layer that decides which image to show depending on the interface actions that it receives. On the other side, the test case checks whether the robot can reproduce the behaviour of the UI log. Promising results were obtained and a number of limitations were identified such that it may be applied in more realistic domains.
Degradable branched polycationic systems for nucleic acid delivery
Authors: Qi Yu , Xu Chen , Xu Fu‐Jian
Published: March 2020

Nowadays, nucleic acid‐based therapy has become a promising way for the treatment of various malignant diseases like cancers. However, the process of nucleic acid delivery is hampered by several extracellular and intracellular obstacles. To overcome these obstacles, many nucleic acid delivery carriers have been developed to achieve improved safety and enhanced gene transfection performance. Among these carriers, degradable branched polycations have attracted much attention due to their good responsive degradability and impressive transfection performances. In this review, we mainly summarized the redox‐ and pH‐responsive degradable branched polycationic systems used for nucleic acid delivery. For responsive degradable branched polycationic systems, the preparation methods were introduced, where amino‐epoxy ring‐opening reaction as a novel step growth approach was mainly presented. The properties of redox‐ and pH‐responsive degradable branched polycationic systems were subsequently introduced and highlighted. We hope this brief review will motivate the delicate design of responsive degradable branched polycationic systems for potential clinical applications.

This article is categorized under:

Biology‐Inspired Nanomaterials > Nucleic Acid‐Based Structures
Microbiome and Cardiovascular Disease
Authors: Herrema Hilde , Nieuwdorp Max , Groen Albert K.
Published: March 2020

Atherosclerotic cardiovascular disease (ASCVD) is a prime example of a systems disease. In the initial phase, apolipoprotein B-containing cholesterol-rich lipoproteins deposit excess cholesterol in macrophage-like cells that subsequently develop into foam cells. A multitude of systemic as well as environmental factors are involved in further progression of atherosclerotic plaque formation. In recent years, both oral and gut microbiota have been proposed to play an important role in the process at different stages. Particularly bacteria from the oral cavity may easily reach the circulation and cause low-grade inflammation, a recognized risk factor for ASCVD. Gut-derived microbiota on the other hand can influence host metabolism on various levels. Next to translocation across the intestinal wall, these prokaryotes produce a great number of specific metabolites such as trimethylamine and short-chain fatty acids but can also metabolize endogenously formed bile acids and convert these into metabolites that may influence signal transduction pathways. In this overview, we critically discuss the novel developments in this rapidly emerging research field.
Exploring anomalous couplings in Higgs boson pair production through shape analysis
Authors: Capozi M. , Heinrich G.
Published: March 2020

Abstract

We classify shapes of Higgs boson pair invariant mass distributions mhh, calculated at NLO with full top quark mass dependence, and visualise how distinct classes of shapes relate to the underlying coupling parameter space. Our study is based on a five-dimensional parameter space relevant for Higgs boson pair production in a non-linear Effective Field Theory framework. We use two approaches: an analysis based on predefined shape types and a classification into shape clusters based on unsupervised learning. We find that our method based on unsupervised learning is able to capture shape features very well and therefore allows a more detailed study of the impact of anomalous couplings on the mhh shape compared to more conventional approaches to a shape analysis.
Emergent Adler-Bardeen theorem
Authors: Mastropietro Vieri
Published: March 2020

Abstract

We consider a QEDd+1, d = 1, 3 lattice model with emergent Lorentz or chiral symmetry, both when the interaction is irrelevant or marginal. While the correlations present symmetry breaking corrections, we prove that the Adler-Bardeen (AB) non-renormalization property holds at a non-perturbative level even at finite lattice: all radiative corrections to the anomaly are vanishing. The analysis uses a new technique based on the combination of non-perturbative regularity properties obtained by exact renormalization Group methods and Ward Identities. The AB property, essential for the renormalizability of the standard model, is therefore a robust feature imposing no constraints on possible symmetry breaking terms, at least in the class of lattice models considered.
Strong dark matter self-interaction from a stable scalar mediator
Authors: Duch Mateusz , Grzadkowski Bohdan , Huang Da
Published: March 2020

Abstract

In face of the small-scale structure problems of the collisionless cold dark matter (DM) paradigm, a popular remedy is to introduce a strong DM self-interaction which can be generated nonperturbatively by a MeV-scale light mediator. However, if such a mediator is unstable and decays into SM particles, the model is severely constrained by the DM direct and indirect detection experiments. In the present paper, we study a model of a self-interacting fermionic DM, endowed with a light stable scalar mediator. In this model, the DM relic abundance is dominated by the fermionic DM particle which is generated mainly via the freeze-out of its annihilations to the stable mediator. Since this channel is invisible, the DM indirect detection constraints should be greatly relaxed. Furthermore, the direct detection signals are suppressed to an unobservable level since fermionic DM scatterings with a nucleon appear at one-loop level. By further studying the bounds from the CMB, supernovae and BBN on the visible channels involving the dark sector, we show that there is a large parameter space which can generate appropriate DM self-interactions at dwarf galaxy scales, while remaining compatible with other experimental constraints.