bluuebunny/crossref_metadata_2025_split huggingface dataset:
Compound hemizygous variants in SERPINA7 gene cause thyroxine‐binding globulin deficiency
Authors: Fang Yanlan , Chen Hong , Chen Qingqing , Wang Chunlin , Liang Li 
Published: February 2021

AbstractSub‐headingCompound hemizygous variants in SERPINA7 gene.BackgroundThyroxine‐binding globulin (TBG) is encoded by SERPINA7 (OMIM. 314200) which is located on Xq22.3. SERPINA7 variants caused TBG deficiency which does not require treatment, but the decreased thyroxine may be misdiagnosed as hypothyroidism. We discovered some variants of TBG caused by alterations that differ from previously reported.Materials and MethodsIn this study, we enrolled 32 subjects from 10 families and sequenced the SERPINA7 genes of TBG‐deficient subjects. Then, variants were analyzed to assess their effect on TBG expression and secretion. Bioinformatics database, protein structure, and dynamics simulation were used to evaluate the deleterious effects. Finally, we identified 2 novel and 4 known variants, and found 26 of 30 subjects carried the p.L303F. The DynaMut predictions indicated the variants (p.E91K, p.I92T, p.R294C, and p.L303F) exhibited decreased stability.ConclusionAnalyses revealed the p.L303F change the protein stability and flexibility, and it had an impact on the function of TBG, but when coexisted with other variants it might change the conformational structure of the protein and aggravate the damage to the protein. We speculated that the existence of a higher number of variants resulted in lower TBG secretion.
A study on fractional COVID‐19 disease model by using Hermite wavelets
Authors: Kumar Sunil , Kumar Ranbir , Momani Shaher , Hadid Samir 
Published: February 2021

The preeminent target of present study is to reveal the speed characteristic of ongoing outbreak COVID‐19 due to novel coronavirus. On January 2020, the novel coronavirus infection (COVID‐19) detected in India, and the total statistic of cases continuously increased to 7 128 268 cases including 109 285 deceases to October 2020, where 860 601 cases are active in India. In this study, we use the Hermite wavelets basis in order to solve the COVID‐19 model with time‐ arbitrary Caputo derivative. The discussed framework is based upon Hermite wavelets. The operational matrix incorporated with the collocation scheme is used in order to transform arbitrary‐order problem into algebraic equations. The corrector scheme is also used for solving the COVID‐19 model for distinct value of arbitrary order. Also, authors have investigated the various behaviors of the arbitrary‐order COVID‐19 system and procured developments are matched with exiting developments by various techniques. The various illustrations of susceptible, exposed, infected, and recovered individuals are given for its behaviors at the various value of fractional order. In addition, the proposed model has been also supported by some numerical simulations and wavelet‐based results.
Evaluation of scatter rejection and correction performance of 2D antiscatter grids in cone beam computed tomography
Authors: Park Yeonok , Alexeev Timur , Miller Brian , Miften Moyed , Altunbas Cem 
Published: February 2021

PurposeWe have been investigating two‐dimensional (2D) antiscatter grids (2D ASGs) to reduce scatter fluence and improve image quality in cone beam computed tomography (CBCT). In this work, two different aspects of 2D ASGs, their scatter rejection and correction capability, were investigated in CBCT experiments. To correct residual scatter transmitted through the 2D ASG, it was used as a scatter measurement device with a novel method: grid‐based scatter sampling.MethodsThree focused 2D ASG prototypes with grid ratios of 8, 12, and 16 were developed for linac‐mounted offset detector CBCT geometry. In the first phase, 2D ASGs were used as a scatter rejection device, and the effect of grid ratio on CT number accuracy and contrast‐to‐noise ratio (CNR) evaluated in CBCT images. In the second phase, a grid‐based scatter sampling method which exploits the signal modulation characteristics of the 2D ASG’s septal shadows to measure and correct residual scatter transmitted through the grid was implemented. To evaluate CT number accuracy, the percent change in CT numbers was measured by changing the phantom from head to pelvis size and configuration.ResultsWhen 2D ASG was used as a scatter rejection device, CT number accuracy increased and the CT number variation due to change in phantom dimensions was reduced from 23% to 2–6%. A grid ratio of 16 yielded the lowest CT number variation. All three 2D ASGs yielded improvement in CNR, up to a factor of two in pelvis‐sized phantoms. When 2D ASG prototypes were used for both scatter rejection and correction, CT number variations were reduced further, to 1.3–2.6%. In comparisons with a clinical CBCT system and a high‐performance radiographic ASG, 2D ASG provided higher CT number accuracy under the same imaging conditions.ConclusionsWhen 2D ASG is used solely as a scatter rejection device, substantial improvement in CT number accuracy can be achieved by increasing the grid ratio. Two‐dimensional ASGs also provided significant CNR improvement even at lower grid ratios. Two‐dimensional ASGs used in conjunction with the grid‐based scatter sampling method provided further improvement in CT number accuracy, irrespective of the grid ratio, while preserving 2D ASGs’ capacity to improve CNR. The combined effect of scatter rejection and residual scatter correction by 2D ASG may accelerate implementation of new techniques in CBCT that require high quantitative accuracy, such as radiotherapy dose calculation and dual energy CBCT.
Automatic segmentation of hippocampus in hippocampal sparing whole brain radiotherapy: A multitask edge‐aware learning
Authors: Qiu Qingtao , Yang Ziduo , Wu Shuyu , Qian Dongdong , Wei Jun , Gong Guanzhong , Wang Lizhen , Yin Yong 
Published: February 2021

PurposeThis study aimed to improve the accuracy of the hippocampus segmentation through multitask edge‐aware learning.MethodWe developed a multitask framework for computerized hippocampus segmentation. We used three‐dimensional (3D) U‐net as our backbone model with two training objectives: (a) to minimize the difference between the targeted binary mask and the model prediction; and (b) to optimize an auxiliary edge‐prediction task which is designed to guide the model detection of the weak boundary of the hippocampus in model optimization. To balance the multiple task objectives, we proposed an improved gradient normalization by adaptively adjusting the weight of losses from different tasks. A total of 247 T1‐weighted MRIs including 131 without contrast and 116 with contrast were collected from 247 patients to train and validate the proposed method. Segmentation was quantitatively evaluated with the dice coefficient (Dice), Hausdorff distance (HD), and average Hausdorff distance (AVD). The 3D U‐net was used for baseline comparison. We used a Wilcoxon signed‐rank test to compare repeated measurements (Dice, HD, and AVD) by different segmentations.ResultsThrough fivefold cross‐validation, our multitask edge‐aware learning achieved Dice of 0.8483 ± 0.0036, HD of 7.5706 ± 1.2330 mm, and AVD of 0.1522 ± 0.0165 mm, respectively. Conversely, the baseline results were 0.8340 ± 0.0072, 10.4631 ± 2.3736 mm, and 0.1884 ± 0.0286 mm, respectively. With a Wilcoxon signed‐rank test, we found that the differences between our method and the baseline were statistically significant (P < 0.05).ConclusionOur results demonstrated the efficiency of multitask edge‐aware learning in hippocampus segmentation for hippocampal sparing whole‐brain radiotherapy. The proposed framework may also be useful for other low‐contrast small organ segmentations on medical imaging modalities.
Temperature‐based MRI safety simulations with a limited number of tissues
Authors: Carluccio Giuseppe , Akgun Can , Vaughan John Thomas , Collins Christopher 
Published: February 2021

PurposeDemonstrate ability to produce reasonable simulations of temperature using numerical models of the human body with a limited number of tissues.MethodsFor both a male and female human body model, numerical simulations were used to calculate temperature distributions in three different models of the same human body: the original model with 35 tissues for the male model and 76 tissues for the female model, a simplified model having only three tissues (muscle, fat, and lung), and a simplified model having six tissues (muscle, fat, lung, bone, brain, and skin).ResultsAlthough a three‐tissue model gave reasonable specific absorption rate estimates in comparison to an original with many more tissues, because of tissue‐specific thermal and physiological properties that do not affect specific absorption rate, such as rate of perfusion by blood, the three‐tissue model did not provide temperature distributions similar to those of the original model. Inclusion of a few additional tissues, as in the six‐tissue model, produced results in much better agreement with those from the original model.ConclusionReasonable estimates of temperature can be simulated with a limited number of tissues, although this number is higher than the number of tissues required to produce reasonable simulations of specific absorption rate. For exposures primarily in the head and thorax, six tissues may be adequate for reasonable estimates of temperature.
Sodiation mechanism via reversible surface film formation on metal oxides for sodium‐ion batteries
Authors: Portenkirchner Engelbert , Rommel Sebastian , Szabados Lukas , Griesser Christoph , Werner Daniel , Stock David , Kunze‐Liebhäuser Julia 
Published: February 2021

AbstractLong term galvanostatic charge/discharge cycling of oxygen deficient, carburized and self‐organized titanium dioxide (TiO2) nanotubes (NTs) in sodium ion (Na) batteries (SIBs) are subject to a significant self‐improving charge storage behavior. Surface reactions upon sodiation of carburized NTs form acicular surface films that can be reversibly cycled. We show that, alongside organic species from the decomposition of the electrolyte, mainly inorganic compounds, such as Na2O2 and Na2CO3, are the main constituents. These components possess a characteristic acicular morphology. Na2O2 is found to form upon sodiation and converted to NaO2 upon desodiation. This, in combination with its pseudo‐capacitive charge storage characteristics, explains the excellent rate capability measured for TiO2‐x‐C NTs. The observed high reversibility of this surface chemistry is also essential for the fast kinetics and the high capacity retention found in the system. Our findings point to a more general Na‐ion storage mechanism, that is potentially relevant to other transition metal oxides also.
Preparation of flame retardant and conductive epoxy resin composites by incorporating functionalized multi‐walled carbon nanotubes and graphite sheets
Authors: Zhang Sheng , Jiang Yichong , Sun Yongyuan , Sun Jun , Xu Bo , Li Hongfei , Gu Xiaoyu 
Published: February 2021

AbstractThis work reports our recent efforts on the preparation of functionalized multi‐walled carbon nanotubes (f‐CNTs) and its application in improving the fire, conductive, and mechanical performance of epoxy resin (EP) composites in combination with graphite sheets (GSs). The addition of hybrid carbon nanomaterials can effectively improve the mechanical properties of epoxy. Consequently, when the mass fraction of f‐CNTs/GSs is 3.9 wt%, the limiting oxygen index (LOI) value is increased to 27.4%, and the tensile strength and notched impact strength of epoxy are increased by 33.5% and 44.8%, respectively. Increasing the content of carbon nanomaterials can further improve the flame retardancy and electrical conductivity of EP composites. For the sample containing 11.0 wt% f‐CNTs/GSs, the electrical conductivity is further increased to 1.7 × 10−3 S/cm, which can be regarded as conductive materials. The LOI value is reached to 28.6%, with peak heat release and total heat release reduced by 26.4% and 16.4%, respectively.
Synergistically enhanced ultraviolet aging resistance and interfacial adhesion of poly (p‐phenylene benzobisoxazole) fiber with soluble naphthalimide sizing
Authors: Lu Kangyi , Ge Xin , Wei Zhenhai , Li Gang , Yang Xiaoping , Liu Hanyang 
Published: February 2021

AbstractAmino‐terminated naphthalimide (NDI) with ultraviolet (UV) absorptivity was synthesized to sizing on poly(p‐phenylene benzobisoxazole) (PBO) fiber surface, and UV aging resistance PBO fiber and interfacial adhesion of their composites was investigated. Compared with pristine PBO fiber, the surface chemical activity and roughness of NDI‐PBO fiber were increased. In comparison with pristine PBO fiber, tensile strength, intrinsic viscosity ([η]), and diameter of NDI‐PBO fiber showed a better retention, and the enhanced UV‐aging resistance was verified by hardly visible macroscopic defects on NDI‐PBO fiber. Meanwhile, transverse fiber bundle test strength of NDI‐PBO fiber composites was promoted by stronger mechanical interlocking and chemical interaction. The synergistic improvement in UV aging resistance and interfacial adhesion of PBO fiber was attributed to undamaged crystal and molecular structure from UV protection effects of NDI layer and strong chemical bonding between reactive groups of NDI and epoxy matrix.
Creating community: Expanding access to psychosocial programs for Latina breast cancer survivors
Authors: Buki Lydia P. , Schwartz Jessica R. , McInerney Elizabeth E. W. 
Published: February 2021

AbstractObjectiveBreast cancer survivors often derive benefits from psychosocial interventions, but less is known about Latina women's experiences. Given the disproportionately high disease burden faced by Latina survivors, it is critical to examine ways to enhance access for this population. Thus, the present study aimed to (a) examine women's perceptions of factors associated with effective delivery of a psychosocial program designed for Spanish speaking women with limited access to care, and (b) identify the mechanisms by which the program enhanced women's psychological well‐being.MethodsIn a qualitative study, in‐depth interviews were conducted with 15 immigrant Latina breast cancer survivors who previously received psychosocial services at a community‐based organization. Grounded theory was used to analyze the data.ResultsThrough open, axial, and selective coding, we arrived at the core category achieving a sense of community. The psychosocial program promoted access and enhanced women's psychological well‐being by creating a sense of community among participants. This was facilitated by three primary aspects of service provision: access factors, a holistic approach to health, and therapeutic factors imparted through a biweekly support group.ConclusionsPsychosocial services promoted a sense of community among Latina breast cancer survivors while reflecting their cultural values and unique psychosocial needs. Findings may guide the development of interventions to increase access to care, enhance health outcomes, and create and maintain a sense of community among medically underserved populations.
How enzymes harness highly unfavorable proton transfer reactions
Authors: Silverstein Todd P. 
Published: February 2021

AbstractAcid–base reactions that are exceedingly unfavorable under standard conditions can be catalytically important at enzyme active sites. For example, in triose phosphate isomerase, a glutamate side chain (nominal pKa ≈ 4 in solution) can in fact deprotonate a CH group that is vicinal to a carbonyl (pKa ≈ 18 in solution). This is true because of three distinct interactions: (a) ground state pKa shifts due to environment polarity and electrostatics; (b) dramatic increases in effective molarity due to optimization of proximity and orientation; and (c) transition state pKa shifts due to binding interactions and the formation of strong low barrier hydrogen bonds. In this report, we review the literature showing that the sum of these three effects supplies more than enough free energy to push forward proton transfer reactions that under standard conditions are exceedingly nonspontaneous and slow.
The interaction of p38 with its upstream kinase MKK6
Authors: Kumar Ganesan Senthil , Page Rebecca , Peti Wolfgang 
Published: February 2021

AbstractMitogen‐activated protein kinase (MAPK; p38, ERK, and JNK) cascades are evolutionarily conserved signaling pathways that regulate the cellular response to a variety of extracellular stimuli, such as growth factors and interleukins. The MAPK p38 is activated by its specific upstream MAPK kinases, MKK6 and MKK3. However, a comprehensive molecular understanding of how these cognate upstream kinases bind and activate p38 is still missing. Here, we combine NMR spectroscopy and isothermal titration calorimetry to define the binding interface between full‐length MKK6 and p38. It was shown that p38 engages MKK6 not only via its hydrophobic docking groove, but also influences helix αF, a secondary structural element that plays a key role in organizing the kinase core. It was also shown that, unlike MAPK phosphatases, the p38 conserved docking (CD) site is much less affected by MKK6 binding. Finally, it was demonstrated that these interactions with p38 are conserved independent of the MKK6 activation state. Together, the results revealed differences between specificity markers of p38 regulation by upstream kinases, which do not effectively engage the CD site, and downstream phosphatases, which require the CD site for productive binding.
Concomitant inpatient prescribing of strong opioids with sedatives: Associations with comorbid conditions
Authors: Li Ray J. , Caughey Gillian E. , Shakib Sepehr 
Published: February 2021

AbstractCo‐prescribing of opioids and sedatives is a known risk factor for opioid‐induced ventilatory impairment (OIVI). Prevalence data for sedative and opioid co‐prescription in inpatients in Australia are unknown. Our objective was to determine the prevalence of inpatient sedative and opioid co‐prescribing and to identify factors associated with co‐prescription. We conducted a retrospective cross‐sectional study from July 2017 to October 2017 across four South Australian hospitals utilizing a centralized electronic health record. Multivariate analysis was used to identify characteristics predictive of co‐prescribing of a strong opioid (fentanyl, hydromorphone, morphine, and oxycodone) and sedative medications (benzodiazepines, antiepileptics, antipsychotics, and tricyclic antidepressants). Of the 6170 inpatients, 2795 (45.3%) were prescribed a strong opioid and of those, 1889 (30.6% of all inpatients) were co‐prescribed a sedative. Of those prescribed a strong opioid, five (0.18%) developed OIVI. Patients prescribed a strong opioid had a 27–77% increased likelihood of being prescribed a sedative. Factors predictive of sedative co‐prescribing included the presence of disease of the central nervous system adjusted OR (aOR) 8.66 [95% CI 5.83–12.9] and respiratory disease aOR 1.42 [95% CI 1.17–1.72]. Nearly, one third of all hospital inpatients were co‐prescribed a strong opioid and a sedative medication. Patients with comorbidities resulting in increased risk of respiratory depression/OIVI were more likely to have sedative co‐prescription. Clinicians should be aware of the effects of high‐risk medications and ensure that systems and monitoring are in place that help mitigate adverse outcomes.
A Mechanistic In Vivo/Ex Vivo Pharmacokinetic‐Pharmacodynamic Model of Tenofovir for HIV Prevention
Authors: Jayachandran Priya , Garcia-Cremades Maria , Vučićević Katarina , Bumpus Namandjé N. , Anton Peter , Hendrix Craig , Savić Radojka 
Published: February 2021

Defining tissue and plasma‐specific prophylactic drug concentrations is central to pre‐exposure prophylaxis product development for sexual transmission of HIV‐1. Pharmacokinetic (PK) data from study RMP‐02/MTN‐006 comparing single dose oral tenofovir disoproxil fumarate with single and multiple dose rectal tenofovir (TFV) gel administration in HIV‐1 seronegative adults was used to construct a multicompartment plasma‐rectal tissue population PK model for TFV and tenofovir‐diphosphate (TFVdp) in plasma and rectal tissue. PK data were collected in five matrices: TFV (plasma, rectal tissue homogenate), TFVdp (peripheral blood mononuclear cells, rectal mononuclear cells (MMCs), rectal tissue homogenate). A viral growth compartment and a delayed effect compartment for p24 antigen expression measured from an ex vivo explant assay described HIV‐1 infection and replication. Using a linear PK/pharmacodynamic model, MMC TFVdp levels over 9,000 fmol/million cells in the explant assay provided apparent viral replication suppression down to 1%. Parameters were estimated using NONMEM version 7.4.
CAD/CAM‐based referencing aids to reduce preoperative radiation exposure for intraoperative navigation
Authors: Zeller Alexander‐Nicolai , Zimmerer Rüdiger M. , Springhetti Sina , Tavassol Frank , Rahlf Björn , Neuhaus Michael‐Tobias , Gellrich Nils‐Claudius 
Published: February 2021

AbstractBackgroundAll intraoperative navigation systems need a referencing procedure prior to utilization, usually requiring an additional computed tomography (CT) or cone beam computed tomograph (CBCT) scan. As new techniques in the field of Computer‐aided design / Computer‐aided manufacturing (CAD/CAM) have evolved, it seemed favourable to develop a new referencing method not relying on additional CT or CBCT scans.MethodsA digital maxillary dental scan was used to create a referencing splint by CAD/CAM containing four reference points. By matching scanned dental model and initial trauma‐CT, the splints position and thus the reference points were digitally simulated. These splints data were imported into the navigation system in Standard Tessellation Language (STL) format. These data were also 3D printed and the resulting piece was placed on the anatomical models' teeth. The methods accuracy was then assessed in vitro.ConclusionOur method for referencing of intraoperative navigation can be feasible to avoid an additional CT or CBCT prior to navigation.
Ranking graphs through hitting times of Markov chains
Authors: De Santis Emilio 
Published: February 2021

AbstractIn the present paper we show that for any given digraph , that is, an oriented graph without self‐loops and 2‐cycles, one can construct a 1‐dependent Markov chain and n identically distributed hitting times T1, … , Tn on this chain such that the probability of the event Ti > Tj, for any i, j = 1, … , n, is larger than if and only if . This result is related to various paradoxes in probability theory, concerning in particular non‐transitive dice.
Voluntary disclosure of greenhouse gas emissions by cities under carbon disclosure project: A sustainable development approach
Authors: Chen Fuzhong , Hussain Muzzammil , Khan Jawad Ahmad , Mir Ghulam Mustafa , Khan Zeeshan 
Published: February 2021

AbstractToday's world is facing a serious challenge of high carbon emissions. A large number of studies are examining the deteriorating impact of carbon emissions at the country or firm level, but the literature on the voluntary carbon disclosure project (CDP) by cities is not rich. Therefore, this study seeks to examine the effect of the population (Pop) and gross domestic product (GDP) on carbon emissions of cities by using data of CDP. The dataset refers to a set of numerous cities from around the world, spanning the period from 2012 to 2016. Random effects panel regression and generalized method of moments (GMM), and quantile regressions techniques have been employed to empirically investigate the discussed relationship and to control the potential endogeneity issues, respectively. According to the results, population and GDP are substantial predictors of carbon emissions in sampled cities. Findings show that not only factories contribute to increasing carbon emissions rate, but cities are equally responsible for these emissions as they put no checks on their economic growth and population. The findings are also robust for policy implications.