bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Synthesis of Methyl Chlorosilanes from Pd‐Mg‐SiO2 Substrates Using Mechanochemistry
Authors: Sparschu Wendy , Larsen Robert , Katsoulis Dimitris 
Published: February 2021

AbstractThe direct reaction of methyl chloride with magnesium and palladium infused silica substrates to synthesize methyl chlorosilanes is reported. First, high energy ball milling on solid Mg‐SiO2 mixtures produces elemental silicon and MgO. When PdCl2 is infused into the mixture, after additional ball milling and high‐temperature reduction under H2, dipalladium silicide (Pd2Si) is produced. The silicon of the Pd2Si readily reacts with MeCl under Müller–Rochow reaction conditions, to produce methyl chlorosilanes at yield ratios analogous to those of the traditional process. The dominant product is Me2SiCl2 (selectivity > 30%), followed by MeSiCl3 and Me3SiCl, with minor amounts of the remaining chlorosilanes. Silicon conversion exceeds 20% for most of the substrates. The elemental palladium, which remains within the Pd‐Mg‐SiO2 contact mass is re‐converted to Pd2Si at the next H2/high‐temperature treatment and reacts again with MeCl to repeat the methyl chlorosilane production. In principle, the resulting cycle of the mechanochemically induced formation of Pd2Si followed by the reaction with MeCl can be repeated until the starting SiO2 converts completely to methyl chlorosilanes.
Influence of material condition and chemical composition on the properties of plasma‐nitrided austenitic steels
Authors: Musekamp J. , Hoche H. , Schmitt T. , Reinders P.‐M. , Oechsner M. , Kästner P. , Bräuer G. 
Published: February 2021

AbstractPlasmanitrieren bietet großes Potenzial, die Verschleißeigenschaften von austenitischen Stählen zu verbessern. Es werden neben den Werkstoffen 1.4307 und 1.4404 die Titan‐stabilisierten Güten 1.4541 und 1.4571 betrachtet, um insbesondere den Einfluss der Titanstabilisierung auf das Nitrierergebnis und das Korrosionsverhalten zu untersuchen. Außerdem wurde untersucht, inwieweit der Herabsetzung der Korrosionseigenschaften durch kaltumformungs‐induzierte Defektstrukturen durch die Titanstabilisierung begegnet werden kann. Im Vergleich zu den Werkstoffen 1.4307 und 1.4404 wird bei beiden titanstabilisierten austenitischen Stählen weniger Stickstoff in Bereichen mit Umformmartensit und niedrigen Nitriertemperaturen eingebaut, während an Gleitbändern eine erhöhte Eindiffusion von Stickstoff zu beobachten ist. Die Korrosionsbeständigkeit verbessert sich generell durch die hier verwendeten Plasmanitrierparameter. Generell bewirkt eine höhere Dicke der beim Plasmanitrieren erzeugten S‐Phase eine bessere Korrosionsbeständigkeit sowie eine höhere Oberflächenhärte. Die Titanstabilisierung hemmt die Stickstoffdiffusion bei hohen Umformmartensitgehalten und niedrigen Nitriertemperaturen und fördert die Diffusion an Gleitlinien.
Slip‐resistant connections in hot‐dip galvanized steel bridge constructions
Authors: Schudlich A.‐K. , Klein M. , Oechsner M. , Grote J. , Ungermann D. 
Published: February 2021

AbstractEconomic efficiency and sustainability in bridge construction are, in addition to the cost of new building, determined by the incurred maintenance costs. Hot‐dip galvanized bridge constructions can achieve a corrosion protection period in the magnitude of their lifetime (≥ 100 years). Hot‐dip galvanized steel structures are well established and state of the art for public and industrial buildings. Various research projects demonstrate hardly any losses on the fatigue strength compared to the non‐galvanized steel components. Welded site joints of hot‐dip galvanized components require a complex pre‐ and post‐treatment of the corrosion protection. Nevertheless, on‐site applied corrosion protection cannot reach the protection durability of a hot‐dip galvanizing. This technological restriction can be avoided by the use of hot‐dip galvanized bolted connections. Slip‐resistant pre‐stressed connections are proved successful in steel bridge construction. Major scientific investigations are not yet available for the use of slip‐resistant connections for hot‐dip galvanized joints. Technical and scientific foundations for the application of hot‐dip galvanized bolted connections in cyclically loaded steel and composite bridge constructions, based on the European standard for steel constructions, are investigated within the scope of a research project at the MPA. The provision of construction and design recommendations is the goal of this project.
Temperature influence on the development of interdiffusion phenomena in MCrAlY‐coated nickel‐based superalloys
Authors: Elsaß M. , Kontermann C. , Oechsner M. 
Published: February 2021

AbstractIn this work, the interdiffusion between a MCrAlY‐bond coat and two different nickel‐based superalloys is evaluated at three temperatures, 950 °C, 980 °C, and 1,050 °C. Of primary interest is the evolution of Kirkendall‐porosity, the β‐depleted zone in the bond coat and the β’‐ depleted zone in the superalloy. The three phenomena arise near the interface between bond coat and superalloy as a result of interdiffusion between both materials and are detrimental to the coating‐substrate system. The evolution of the interdiffusion phenomena is highly dependent on the alloy composition of the materials as well as the annealing temperature. It has been found that not only the temperature dependency of the diffusion coefficient but also the temperature dependent element activities are an important factor when evaluating the interdiffusion phenomena. It has further been shown that at lower temperatures the amount of Kirkendall‐porosity per volume fraction is higher than at higher temperatures, even though the overall amount of porosity is lower. Different equilibrium concentrations of main alloying elements and a correspondingly lower over‐saturation of vacancies have been identified as the main explanation.
Inhibition of BRAF and ERK1/2 has synergistic effects on thyroid cancer growth in vitro and in vivo
Authors: Hicks Hannah M. , McKenna Logan R. , Espinoza Veronica L. , Pozdeyev Nikita , Pike Laura A. , Sams Sharon B. , LaBarbera Daniel , Reigan Philip , Raeburn Christopher D. , E. Schweppe Rebecca 
Published: February 2021

AbstractMutations in the BRAF gene are highly prevalent in thyroid cancer. However, the response rate of thyroid tumors to BRAF‐directed therapies has been mixed. Increasingly, combination therapies inhibiting the MAPK pathway at multiple nodes have shown promise. Recently developed ERK1/2 inhibitors are of interest for use in combination therapies as they have the advantage of inhibiting the most downstream node of the MAPK pathway, therefore preventing pathway reactivation. Here, we examined the effect of combined BRAF inhibition (dabrafenib) and ERK1/2 inhibition (SCH772984) on the growth and survival of a panel of BRAF‐mutant thyroid cancer cell lines using in vitro and in vivo approaches. We found that resistance due to MAPK pathway reactivation occurs quickly with single‐agent BRAF inhibition, but can be prevented with combined BRAF and ERK1/2 inhibition. Combined inhibition also results in synergistic growth inhibition, decreased clonogenic survival, and enhanced induction of apoptosis in a subset of BRAF‐mutant thyroid cancer cells. Finally, combined inhibition of BRAF and ERK1/2 results in enhanced inhibition of tumor growth in an anaplastic thyroid cancer in vivo model. These results provide key rationale to pursue combined BRAF and ERK1/2 inhibition as an alternative therapeutic strategy for BRAF‐mutant advanced thyroid cancer patients.
Evidence for Non‐Mendelian Inheritance in Spastic Paraplegia 7
Authors: Estiar Mehrdad A. , Yu Eric , Haj Salem Ikhlass , Ross Jay P. , Mufti Kheireddin , Akçimen Fulya , Leveille Etienne , Spiegelman Dan , Ruskey Jennifer A. , Asayesh Farnaz , Dagher Alain , Yoon Grace , Tarnopolsky Mark , Boycott Kym M. , Dupre Nicolas , Dion Patrick A. , Suchowersky Oksana , Trempe Jean‐Francois , Rouleau Guy A. , Gan‐Or Ziv 
Published: February 2021

AbstractBackgroundAlthough the typical inheritance of spastic paraplegia 7 is recessive, several reports have suggested that SPG7 variants may also cause autosomal dominant hereditary spastic paraplegia (HSP).ObjectivesWe aimed to conduct an exome‐wide genetic analysis on a large Canadian cohort of HSP patients and controls to examine the association of SPG7 and HSP.MethodsWe analyzed 585 HSP patients from 372 families and 1175 controls, including 580 unrelated individuals. Whole‐exome sequencing was performed on 400 HSP patients (291 index cases) and all 1175 controls.ResultsThe frequency of heterozygous pathogenic/likely pathogenic SPG7 variants (4.8%) among unrelated HSP patients was higher than among unrelated controls (1.7%; OR 2.88, 95% CI 1.24–6.66, P = 0.009). The heterozygous SPG7 p.(Ala510Val) variant was found in 3.7% of index patients versus 0.85% in unrelated controls (OR 4.42, 95% CI 1.49–13.07, P = 0.005). Similar results were obtained after including only genetically‐undiagnosed patients. We identified four heterozygous SPG7 variant carriers with an additional pathogenic variant in known HSP genes, compared to zero in controls (OR 19.58, 95% CI 1.05–365.13, P = 0.0031), indicating potential digenic inheritance. We further identified four families with heterozygous variants in SPG7 and SPG7‐interacting genes (CACNA1A, AFG3L2, and MORC2). Of these, there is especially compelling evidence for epistasis between SPG7 and AFG3L2. The p.(Ile705Thr) variant in AFG3L2 is located at the interface between hexamer subunits, in a hotspot of mutations associated with spinocerebellar ataxia type 28 that affect its proteolytic function.ConclusionsOur results provide evidence for complex inheritance in SPG7‐associated HSP, which may include recessive and possibly dominant and digenic/epistasis forms of inheritance. © 2021 International Parkinson and Movement Disorder Society
Temporal and spatial analysis of thermal stress and its trend in Iran
Authors: Mohammadi Bakhtiyar , Barnameh Samireh , Matzarakis Andreas 
Published: February 2021

AbstractThe study was conducted to determine thermal stress and its trend in Iran. The atmospheric variables of 304 synoptic stations, including mean temperature, relative humidity, wind speed and cloudiness, for the period 1961–2010, were used to identify the thermal stress conditions in Iran. These data were prepared on a daily basis from the Iran Meteorological Organization. Physiologically equivalent temperature (PET) and standard effective temperature (SET*) were used to identify thermal stress. Also, thermal stress was studied with a simple linear regression method and at a 95% confidence level. The results of the study revealed that in Iran each location can experience different types of environmental conditions throughout the year. At a specified time, thermal stresses of different intensities can be seen. The other results showed that the mountainous regions, especially the highlands of the northwest, along with the Zagros and Alborz mountains, had the highest co‐efficient of variability (> 50%). Also, the southern regions of Iran have both monthly and annual scales with the least co‐efficient of variability (< 20%) in bioclimatic conditions. In general, a diversity of bioclimatic conditions is evident in Iran both temporally and spatially. The other part of the study determined that heat and cold stress and heat comfort had a positive trend (fewer than 60 stations) in parts of Iran, a negative trend in some other parts (more than 50 stations), and no specific trend in the remaining parts (more than 250 stations). Most of the northern stations, especially on the Caspian coast, have been shown to have a positive trend in the event of cold stress. Indeed, extreme bioclimatic conditions (very cold and hot conditions) have been rising in both the southern and northern latitudes of the country. Even in southern parts, a positive trend of cold and very cold conditions can be observed at some stations.
Fully tunable filter‐antenna with microstrip and quarter‐mode substrate‐integrated waveguide hybrid structure
Authors: Yu Mengyuan , You Bin , Cheng Lin 
Published: February 2021

AbstractThis letter proposed a filter‐antenna with continuously adjustable center frequency and bandwidth. The proposed filter‐antenna employs a hybrid structure of a microstrip and quarter‐mode substrate‐integrated waveguide (QSIW). The simulation and test results show that the CF of the filter‐antenna can be continuously tuned between 1.35GHz and 1.472GHz, and the 10‐dB BW is continuously tuned between 30 MHz‐104 MHz. The simulated antenna radiation pattern can maintain good stability in the adjustable range.
Dual‐band terahertz metamaterial absorber using hexagon graphene structure
Authors: Lu Zhonghao , Yang Yong‐Gang , Huang Jian‐Lin 
Published: February 2021

AbstractA dual‐band terahertz metamaterial absorber using one‐layer periodically patterned hexagon graphene structure is proposed. By periodically loading six graphene stubs to the honeycomb hexagon graphene structure without increase of the overall size, a new high‐frequency absorption peak will be obtained to realize a dual‐band frequency response. By tuning the structural parameters or Fermi energy levels of the presented terahertz metamaterial absorber, both of the two absorption bands will be changed to the required working frequencies for design specifications. Moreover, the proposed terahertz metamaterial absorber has the properties of polarization independence and incident angle insensitivity, which are of great significance in the applications of some detecting and sensing systems. This work will be a good candidate for the design guidance of various metamaterial absorbers using graphene with single or dual absorption bands.
Design and analysis of nickel ferrite resonator antenna for C band applications
Authors: da Silva Isaac Barros Tavares , D'Assunção Adaildo Gomes , de Oliveira João Bosco Lucena , de Holanda Samanta Mesquita , Cordeiro Carlos Henrique Nascimento 
Published: February 2021

AbstractThis article shows the design of dielectric resonator antenna with nickel ferrite as dielectric material. Its main characteristics and measurements are described. Nickel ferrite was synthetized by sol–gel modified by ionic coordination reaction technique. Calcination was performed at 1100°C (10 h, 10°C/min step), followed by compression procedure at 227 MPa, to manufacture the bulk. Sintering process was applied at calcination temperature, for 4 h, to ensure bulk's physical resistance, and its electrical characterization was performed for antenna design and simulations. Simulated radiation patterns are presented, as reflection coefficient, which is compared with measurements. Measured reflection coefficient presented good agreement with performed simulations, with a difference of 0.74% in resonance frequency. Simulated radiation patterns also presented good results, with relatively high gain in co‐polarization planes, 2.11 dB for E plane, and low cross‐polarization E plane value, −47 dB.
Highly sensitive temperature sensor based on multimode‐interference fiber structure with gel cladding
Authors: Sakata Hajime , Okada Kengo , Mochizuki Jun 
Published: February 2021

AbstractWe present a temperature‐sensitive, single‐mode–multimode–single‐mode (SMS) fiber structure with an index‐matching gel as a cladding material in a multimode segment. A silica core with the surrounding gel is supported straight by a thin glass tube to produce a bandpass transmission response. The passband wavelength shifts by 96 nm from 1624.5 to 1528.5 nm as the temperature increased from 40 to 200°C. The maximum sensitivity obtained is 2 nm/°C in the temperature range 40–70°C, whereas the minimum sensitivity is 0.13 nm/°C in the temperature range 125–200°C. The SMS fiber structure, including the gel cladding, allows high operating temperatures and high thermal sensitivities.
A multicompartment model for intratumor tissue‐specific analysis of DCE‐MRI using non‐negative matrix factorization
Authors: Xie Yuhai , Zhao Jun , Zhang Puming 
Published: February 2021

PurposeA pharmacokinetic analysis of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) data is subject to inaccuracy and instability partly owing to the partial volume effect (PVE). We proposed a new multicompartment model for a tissue‐specific pharmacokinetic analysis in DCE‐MRI data to solve the PVE problem and to provide better kinetic parameter maps.MethodsWe introduced an independent parameter named fractional volumes of tissue compartments in each DCE‐MRI pixel to construct a new linear separable multicompartment model, which simultaneously estimates the pixel‐wise time‐concentration curves and fractional volumes without the need of the pure‐pixel assumption. This simplified convex optimization model was solved using a special type of non‐negative matrix factorization (NMF) algorithm called the minimum‐volume constraint NMF (MVC‐NMF).ResultsTo test the model, synthetic datasets were established based on the general pharmacokinetic parameters. On well‐designed synthetic data, the proposed model reached lower bias and lower root mean square fitting error compared to the state‐of‐the‐art algorithm in different noise levels. In addition, the real dataset from QIN‐BREAST‐DCE‐MRI was analyzed, and we observed an improved pharmacokinetic parameter estimation to distinguish the treatment response to chemotherapy applied to breast cancer.ConclusionOur model improved the accuracy and stability of the tissue‐specific estimation of the fractional volumes and kinetic parameters in DCE‐MRI data, and improved the robustness to noise, providing more accurate kinetics for more precise prognosis and therapeutic response evaluation using DCE‐MRI.
Three‐dimensional spatially resolved phase graph framework
Authors: Gao Xiang , Kiselev Valerij G. , Lange Thomas , Hennig Jürgen , Zaitsev Maxim 
Published: February 2021

PurposeAn open‐source spatially resolved phase graph framework is proposed for simulating arbitrary pulse sequences in the presence of piece‐wise constant gradients with arbitrary orientations in three dimensions. It generalizes the extended phase graph algorithm for analysis of nonperiodic sequences while preserving its efficiency, and is able to estimate the signal modulation in the 3D spatial domain.MethodsThe framework extends the recursive magnetization‐evolution algorithm to account for anisotropic diffusion and exploits a novel 3D k‐space grid‐merging method to balance the computational effort and memory requirements against acceptable simulation errors. A new postsimulation module is proposed to track and visualize the signal evolution both in the k‐space and in the image domain, which can be used for simulating image artifacts or finding frequency‐response profiles. To illustrate the developed technique, three examples are presented: (1) fast off‐resonance calculation for dictionary building in MR fingerprinting, (2) validation of a steady‐state sequence with quasi‐isotropic diffusion weighting, and (3) investigation of the magnetization evolution in PRESS‐based spectroscopic imaging.ResultsThe grid‐merging algorithm of the proposed framework demonstrates high calculation efficiency exemplified by frequency‐response simulation of pseudo steady‐state or diffusion‐weighted steady‐state sequences. It further helps to visualize the signal evolution in PRESS‐based sequences.ConclusionsThe proposed simulation framework has been validated based on several different example applications for analyzing signal evolution in the frequency and spatial domain.
Prevalence of high‐risk bladder categorization with prenatal and postnatal myelomeningocele repair types
Authors: Gerber Jonathan A. , Stocks Blair T. , Zhu Huirong , Castillo Heidi , Castillo Jonathan , Borden Alexandra N. , Tu Duong D. , Whitehead William E. , Austin Paul F. 
Published: February 2021

AbstractIntroductionUrologic substudies of prenatal myelomeningocele (MMC) closure have focused primarily on continence without significant clinical benefit. Fetoscopic MMC repair (FMR) is a newer form of prenatal intervention and touts added benefits to the mother, but urological outcomes have yet to be analyzed. We set out to focus on bladder safety rather than continence and examined bladder outcomes with different prenatal MMC repairs (FMR and prenatal open [POMR]) and compared bladder‐risk‐categorization to traditional postnatal repair (PSTNR).MethodsAn IRB‐approved retrospective analysis of all patients undergoing all forms of MMC repairs with inclusion and exclusion criteria based on the MOMS trial was performed. Bladder safety assessment required initial urodynamic studies (UDS), renal bladder ultrasound (RBUS), and/or voiding cystourethrogram (VCUG) within the 1st year of life. Follow‐up analyses within the cohorts required follow‐up studies within 18 months after initial evaluations. Outcomes assessed included bladder‐risk‐categorization based on the CDC UMPIRE study (high, intermediate, and safe), hydronephrosis (HN), and vesicoureteral reflux (VUR). A single reader evaluated each UDS.ResultsInitial UDS in 93 patients showed that the prevalence of high‐risk bladders were 35% FMR versus 36% PSTNR and 60% POMR. Follow‐up UDS showed only 8% of FMR were high‐risk compared to 35% POMR and 36% PSTNR. Change from initial to follow‐up bladder‐risk‐category did not reach significance (p = .0659); however, 10% PSTNR worsened to high‐risk on follow‐up, compared to none in either prenatal group. Subanalysis of follow‐up UDS between the prenatal cohorts also was not significant (p = .055). Only 8% of FMR worsened or stayed high‐risk compared to 35% with POMR (p = .1). HN was significantly different at initial and subsequent follow up between the groups with the least in the FMR group.ConclusionsEarly outcome UDS analyses demonstrated lower incidence of high‐risk bladders in FMR patients with a trend toward clinically significant improvement compared to POMR in regard to all evaluated metrics. Larger, prospective, confirmatory studies are needed to further evaluate the potential benefits on FMR on bladder safety and health.
Demand estimation of mass‐gathering healthcare in developing countries: The case of Kumbh Mela in India
Authors: Zhao Tiancheng , Ye Han , Mukherjee Ujjal Kumar , Chhajed Dilip 
Published: February 2021

AbstractA mass‐gathering is defined as a congregation of a relatively large number of people in a specific location for a specific purpose over a short duration of time. Managing Mass‐Gathering Healthcare (MGH), especially in resource‐constrained regions, is a key policy challenge. Planning and preparation for MGH require understanding the sources, and estimation of demand. We propose a spatio‐temporal Poisson point process model for MGH demand estimation that considers the associated risk factors. We analyze admissions data from a multi‐specialty hospital in Ujjain, India, spanning a period before, during, and after Kumbh Mela, one of the larger religious gatherings globally. The results show that the effect of mass‐gathering on hospital admissions is heterogeneous across disease groups. We identify key socio‐economic and healthcare infrastructural factors that are associated with MGH demand. We establish the external‐validity of the results by demonstrating that mass‐gatherings generally increase the spatial dependence across regions, particularly where availability of healthcare infrastructure is relatively low. Finally, we discuss policy insights for managing MGH.