bluuebunny/crossref_metadata_2025 huggingface dataset:
La evaluación de los obstáculos a la investigación por parte de estudiantes universitarios: construcción de una escala [The Assessment of Obstacles to Research by College Students: Building a Scale]
Authors: Criollo Marco , Recio Patricia
Published: May 2021

ResumenRealizar investigaciones científicas resulta complejo para algunos estudiantes universitarios. Por este motivo se planteó como objetivo crear una escala que mida los obstáculos para investigar. Participaron 650 estudiantes que estaban realizando sus Trabajos Finales de Grado en la Universidad Técnica de Machala-Ecuador. Se desarrolló un grupo inicial de 32 ítems basados en literatura previa. Basándonos en los resultados de la validación de contenido se eliminaron siete ítems. Los resultados del análisis factorial exploratorio (AFE) y confirmatorio (AFC) revelan que los ítems se estructuran en un modelo bifactorial de 24 ítems. En cuanto a la fiabilidad, la escala mostró un alfa de Cronbach y un coeficiente Omega de 0.92 indicando una alta consistencia interna. Se concluye que la escala presenta adecuadas propiedades psicométricas para medir los obstáculos para investigar en los estudiantes universitarios. AbstractConducting scientific research is complex for some university students. For this reason, the objective was to create a scale that measures the obstacles to investigate. 650 students who were doing their Final Degree Works at the Universidad Técnica de Machala-Ecuador participated. An initial group of 32 items was developed based on previous literature. Based on the results of the content validation, 7 items were eliminated. The results of the exploratory factor analysis (EFA) and confirmatory (CFA) reveal that the items are structured in a bifactorial model of 24 items. Regarding reliability, the scale showed a Cronbach's alpha and an Omega coefficient of 0.92, indicating high internal consistency. It is concluded that the scale presents adequate psychometric properties to measure the obstacles to investigate in university students
Endoscopic Management of Staple Line Leak after Bariatric Surgery: Surgeon’s Perspective
Authors: Chung Yoona , Park Dae Geun , Kim Yong Jin
Published: May 2021

Laparoscopic sleeve gastrectomy (LSG) has become a standalone primary procedure as a bariatric metabolic surgery since the early 2000s. The overall complication rate of LSG is reported to range from 2% to 15%. Staple line leakage (SLL) remains a major adverse event and occurs in approximately 1–6% of patients. Choosing the optimal treatment modality is a complex process. Clinicians must understand that nutritional support and drainage of fluid collection are essential for initial management. Conservative endoscopic management and sufficient drainage can resolve approximately 70% of SLLs. Endoscopic management of bariatric complications has been rapidly evolving in recent years and can be considered in all patients who are hemodynamically stable. We will review the available endoscopic management techniques, including stent placement (self-expanding stents and bariatric-specific stents), clipping, tissue sealant application, and internal drainage (double-pigtail stents [DPS] placement, endoscopic vacuum therapy, and septotomy). Stent placement remains the mainstream treatment for SLLs. However, healing with stents requires multiple sessions/stents and a long course of recovery. Endoscopic internal drainage is gaining popularity and has the potential to be a superior method. The importance of early intervention and combined endoscopic methods should be recognized.
Clinical findings influencing time to menarche post gonadotropin-releasing hormone agonist therapy in central precocious puberty
Authors: Wu Vickie , Zhao Victoria , Issa Rula , Wilkes Meredith , Wallach Elizabeth , Rapaport Robert , Romero Christopher , Yau Mabel
Published: May 2021

Purpose: This study aimed to evaluate the time interval to menarche after gonadotropin-releasing hormone agonist (GnRHa) treatment in females with central precocious puberty (CPP) and to identify factors contributing to timing of menarche.Methods: We retrospectively reviewed medical records of 39 females with CPP who reached menarche after GnRHa treatment (leuprolide or histrelin). CPP diagnostic criteria were breast development at <8 years old, measurable pubertal luteinizing hormone and/or estradiol concentrations, and bone age advancement. Indications to treat were advanced bone age and psychosocial concerns. Descriptive summaries were reported as frequency and proportion for categorical variables and mean and standard deviation for continuous measures. Linear regression models were developed to evaluate the associations of clinical factors with the time interval to menarche.Results: Mean age was 9.4±1.6 years at treatment onset, and treatment duration was 2.2±1.4 years. Menarche occurred at 12.6±1.1 years, which was 1.04±0.5 years after treatment discontinuation. This was negatively associated with Tanner stage of breast development and bone age at treatment onset and change in bone age during treatment. No association was seen between time interval to menarche and treatment duration, medication, or body mass index.Conclusion: We found the average time interval to menarche after GnRHa treatment in our population of female patients with CPP to be 1.04±0.5 years; this is in agreement with other reports. Tanner stage of breast development, bone age at treatment onset, and change in bone age were negatively associated with time interval to menarche. These data provide clinical correlates that assist providers during anticipatory guidance of patients with CPP after GnRHa treatment.
Effect of body mass index on peak growth hormone level after growth hormone stimulation test in children with short stature
Authors: Lee Na Yeong , Kim Sung Eun , Kim Seulki , Ahn Moon Bae , Kim Shin Hee , Cho Won Kyoung , Cho Kyoung Soon , Jung Min Ho , Suh Byung-Kyu
Published: May 2021

Purpose: The aim of this study is to evaluate the effect of body mass index (BMI) on peak serum growth hormone (GH) level after GH stimulation test in children with short stature.Methods: Data were obtained from retrospective medical record reviews of those who visited the pediatric endocrine clinic at St. Vincent’s Hospital of Catholic University for short stature from January 2010 to June 2019. A total of 115 children (66 boys and 49 girls) whose height was less than the third percentile according to age and sex underwent GH stimulation testing.Results: Of the 115 subjects, 47 were diagnosed with GH deficiency (GHD) and 68 were diagnosed with idiopathic short stature (ISS). In patients with GHD, weight standard deviation score (SDS) (P<0.001) and BMI SDS (P≤0.001) were higher, and free thyroxine (T4) level (P=0.012) was lower than those in the ISS group. In total subjects, peak serum GH level after GH stimulation test showed negative correlations with weight SDS (r=-0.465, P<0.001), BMI SDS (r=-0.398, P<0.001), and thyroid stimulating hormone (r=-0.248, P=0.008) and a positive correlation with free T4 (r=0.326, P<0.001). In multiple regression analysis, BMI SDS (P=0.003) was negatively associated with peak serum GH level in GH stimulation testing after adjusting for age, sex, pubertal status, and type of pharmacological stimulus.Conclusion: The BMI SDS influences peak serum GH level after GH stimulation testing. We should consider BMI factors when interpreting the results of GH stimulation testing.
NHR-49/PPAR-α and HLH-30/TFEB cooperate for C. elegans host defense via a flavin-containing monooxygenase
Authors: Wani Khursheed A , Goswamy Debanjan , Taubert Stefan , Ratnappan Ramesh , Ghazi Arjumand , Irazoqui Javier E
Published: May 2021

The model organism Caenorhabditis elegans mounts transcriptional defense responses against intestinal bacterial infections that elicit overlapping starvation and infection responses, the regulation of which is not well understood. Direct comparison of C. elegans that were starved or infected with Staphylococcus aureus revealed a large infection-specific transcriptional signature, which was almost completely abrogated by deletion of transcription factor hlh-30/TFEB, except for six genes including a flavin-containing monooxygenase (FMO) gene, fmo-2/FMO5. Deletion of fmo-2/FMO5 severely compromised infection survival, thus identifying the first FMO with innate immunity functions in animals. Moreover, fmo-2/FMO5 induction required the nuclear hormone receptor, NHR-49/PPAR-α, which controlled host defense cell non-autonomously. These findings reveal an infection-specific host response to S. aureus, identify HLH-30/TFEB as its main regulator, reveal FMOs as important innate immunity effectors in animals, and identify the mechanism of FMO regulation through NHR-49/PPAR-α during S. aureus infection, with implications for host defense and inflammation in higher organisms.
O-GlcNAcylation is a key regulator of multiple cellular metabolic pathways
Authors: Zhang Hongshuo , Li Zhen , Wang Yufei , Kong Ying
Published: May 2021

O-GlcNAcylation modifies proteins in serine or threonine residues in the nucleus, cytoplasm, and mitochondria. It regulates a variety of cellular biological processes and abnormal O-GlcNAcylation is associated with diabetes, cancer, cardiovascular disease, and neurodegenerative diseases. Recent evidence has suggested that O-GlcNAcylation acts as a nutrient sensor and signal integrator to regulate metabolic signaling, and that dysregulation of its metabolism may be an important indicator of pathogenesis in disease. Here, we review the literature focusing on O-GlcNAcylation regulation in major metabolic processes, such as glucose metabolism, mitochondrial oxidation, lipid metabolism, and amino acid metabolism. We discuss its role in physiological processes, such as cellular nutrient sensing and homeostasis maintenance. O-GlcNAcylation acts as a key regulator in multiple metabolic processes and pathways. Our review will provide a better understanding of how O-GlcNAcylation coordinates metabolism and integrates molecular networks.
Veteran adherence to oral versus injectable AUD medication treatment
Authors: Stewart Hayden , Mitchell Brian G. , Ayanga Daniel , Walder Annette
Published: May 2021

Introduction

AUD medication treatment has been shown to improve outcomes compared with placebo when confined to per-protocol analysis. The same outcomes, however, have not always been maintained in intent-to-treat analysis, thus suggesting adherence may have a significant impact on efficacy outcomes. There is conflicting evidence present in the literature comparing adherence to oral versus injectable AUD pharmacotherapy and a paucity of information in the veteran population on risk factors for low adherence.

Methods

The primary end point of this retrospective chart review was to determine whether adherence rates differ between oral and injectable AUD treatments in veterans during the first year of treatment (at 3, 6, 9, and 12 months) using the portion of days covered model. Secondary end points were to determine differing characteristics between patients with high versus low adherence and compare alcohol-related readmission rates and discontinuation rates between groups.

Results

Adherence to injectable extended-release (XR) naltrexone was significantly higher than oral naltrexone at all time points and was significantly higher than disulfiram at 3, 6, and 9 months, but it was not significantly different from acamprosate at any time point. At months 9 and 12, acamprosate had significantly higher adherence compared with oral naltrexone. Patients with higher adherence were seen more frequently in the mental health clinic and had previously tried more AUD medications. The discontinuation rates and alcohol-related admission rates were not significantly different between groups at 1 year.

Discussion

XR naltrexone may improve adherence rates compared with oral naltrexone or disulfiram, but not acamprosate based on these outcomes. Patients may have increased adherence if they are seen more often in clinic and have trialed more AUD medications.
Mice lacking endogenous TRPV1 express reduced levels of thermogenic proteins and are susceptible to diet‐induced obesity and metabolic dysfunction
Authors: Baskaran Padmamalini , Nazminia Kara , Frantz Justine , O’Neal Jessica , Thyagarajan Baskaran
Published: May 2021

Transient receptor potential vanilloid subfamily 1 (TRPV1) is a non‐selective cation channel protein expressed in neuronal and non‐neuronal cells. Although TRPV1 is implicated in thermogenesis and diet‐induced obesity (DIO), its precise role remains controversial. TRPV1−/− mice are protected from DIO, while TRPV1 activation enhances thermogenesis to prevent obesity. To reconcile this, we fed wild‐type and TRPV1−/− mice for 32 weeks with normal chow or a high‐fat diet and analyzed the weight gain, metabolic activities, and thermogenic protein expression in white and brown fats. TRPV1−/− mice became obese, exhibited reduced locomotor activity, reduced energy expenditure, enhanced hepatic steatosis, and decreased thermogenic protein expression in adipose tissues. Our data reveal that lack of TRPV1 does not prevent obesity, but rather enhances metabolic dysfunction.
Selection of lactic acid bacteria from native grass silage and its effects as inoculant on silage fermentation
Authors: You Sihan , Du Shuai , Ge Gentu , Wan Tao , Jia Yushan
Published: May 2021

The study aimed to isolate, characterize, and identify wild lactic acid bacteria (LAB) strains from native grass silage on the Inner Mongolian Plateau, and the effects of wild LAB strains on the nutritive and fermentation characteristics of sorghum–sudangrass hybrid (Sorghum bicolor L. × S. sudanense L.) silage were also investigated. These isolates were evaluated using morphological, physiological, and biochemical tests. Three isolated strains were Gram‐positive, homofermentative, catalase‐negative, not produce gas from glucose, and rod‐shaped. These strains could grow normally at pH 3.5–8.0, 15–30 ˚C and NaCl 3 and 6.5%. They were identified as Lactobacillus plantarum group by sequencing 16S rRNA. Compared to uninoculated silage, all LAB‐inoculated silages significantly (P < .05) increased lactic acid (LA) content and ratios of lactic acid/acetic acid (LA/AA), while, reduced pH and ammonia nitrogen (NH3–N). Among all the isolated LAB strains, XM2 showed the highest (P < .05) crude protein (CP), LA, ratio of LA/AA and LAB, lowest (P < .05) pH, AA, propionic acid (PA), butyric acid (BA), NH3–N than the other isolated LAB strains. Strain XM2 is a potential starter culture for sorghum–sudangrass hybrid silage.
Investigations on New Electrolyte Composition and Modified Membrane for High Voltage Zinc−Manganese Hybrid Redox Flow Batteries
Authors: Naresh Raghu pandiyan , Mariyappan K. , Dixon Ditty , Ulaganathan M. , Ragupathy P.
Published: May 2021

In this work, the effect of electrolyte composition and the pore filled membrane was investigated in zinc−manganese (Zn−Mn) hybrid redox flow battery (HRFB). Among the studied electrolytes compositions, sulfate‐based electrolyte composition exhibits an improved performance at various conditions. Further, to minimize the ion crossover, the Daramic membrane is modified using polyacrylonitrile (PAN) as a pore filling agent. Hence, the flow cell fabricated with the optimized electrolyte and modified membrane enhanced the overall cell performance, particularly the energy efficiency of 75.45 % was achieved for the optimized conditions. As configured Zn−Mn flow cell system showed high avg. discharge plateau of 1.91 V at 10 mA cm−2. Further, the cell employed the modified membrane experienced the highly improved performance up to 40 mA cm−2. Besides that, the durability of the Zn−Mn system employing PAN filled Daramic membrane revealed the consistent cell performance over 100 galvanostatic charge‐discharge (GCD) cycles. Thus, the proposed sulfate‐based precursors electrolyte combinations and PAN filled Daramic membrane can be considered as a proficient candidate for obtaining better performance Zn−Mn flow cell system.
Decreasing trends in thyroid cancer incidence in South Korea: What happened in South Korea?
Authors: Oh Chang‐Mo , Lim Jiwon , Jung Yuh Seog , Kim Yeol , Jung Kyu‐Won , Hong Seri , Won Young‐Joo
Published: May 2021

Background

South Korea has the highest incidence of thyroid cancer in the world. Our study examined the trends in thyroid cancer incidence by the histologic type, cancer stage, and age group and explored possible factors that affected thyroid cancer trends.

Methods

We conducted a descriptive epidemiological study using the national cancer registry data and cause of death data from 1999 to 2016 in South Korea. Age‐standardized rates were calculated using Segi's world standard population. Joinpoint regression analysis was applied to determine the changing point of thyroid cancer trends according to histologic type; Surveillance, Epidemiology, and End Results (SEER) summary stage; and age groups by sex.

Results

The age‐standardized incidence of thyroid cancer in both men and women increased from 6.3 per 100,000 people in 1999 to 63.4 per 100,000 in 2012 but declined from 2012 to 2016, before the debates for over diagnosis of thyroid cancer began in 2014. The age‐standardized mortality rate of thyroid cancer, incidence of distant thyroid cancer, and incidence of regional and localized thyroid cancer started to decline since early 2000, 2010, and 2012, respectively. In addition, thyroid cancer prevalence in thyroid nodules showed decreasing trends from 1999–2000 to 2013–2014.

Conclusions

The incidence of thyroid cancer began declining from 2012, before the debates for over diagnosis of thyroid cancer began in 2014. Changes in guidelines for thyroid nodule examinations may have affected this inflection point. Moreover, the debates for over diagnosis of thyroid cancer may have accelerated the decline in thyroid cancer.
Functional characteristics and structural properties of soybean protein isolate–maltose conjugates
Authors: Bu Guanhao , Ren Mengke , Zuo Yingxin , Zhao Chenyu
Published: May 2021

Background and objectives

Glycation is a natural and green modification method and can be used to improve the functional properties of proteins. In this study, the effects of reaction conditions on structural characteristics and functional properties of soy protein isolate (SPI) conjugated with maltose (M) were investigated.

Findings

When the mass ratio of protein and maltose was 1:2 and reaction temperature was 60°C, the degree of grafting of SPI‐M conjugates was highest and the degree of browning was moderate. The solubility of SPI‐M conjugates increased by 48.5%; after 60 hr of reaction, and the emulsification activity index and the emulsion stability index of SPI‐M conjugates increased by 79.4% and 102%, respectively. SDS‐PAGE and FT‐IR indicated that the introduction of maltose led to changes in the spatial structure of the SPI. The in vitro pancreatic digestibility of SPI‐M conjugates also was improved.

Conclusion

The solubility, emulsification, and the in vitro digestibility of SPI‐M conjugates were improved. The spatial structure of SPI was changed after glycation.

Significance and novelty

The results showed that glycation can improve the functional properties of SPI and provide a theoretical basis for the development of new soybean protein products.
Reconstruction of Copper Nanoparticles at Electrochemical CO2 Reduction Reaction Conditions Occurs via Two‐step Dissolution/Redeposition Mechanism
Authors: Popovic Stefan , Bele Marjan , Hodnik Nejc
Published: May 2021

Copper is still the monometallic electrocatalyst of choice for electrochemical reduction of CO2 (ERC) when added‐value products, such as hydrocarbons and alcohols, are desired. However, severe morphological and structural changes are observed upon exposure to the ERC operation conditions. One of the pending questions in the community is what the mechanism behind this reconstruction is. In the present study, pulse‐electrodeposited copper nanoparticles were exposed to different ERC relevant reductive potentials and tracked with identical location scanning electron microscopy (IL‐SEM). This approach provides information on the morphological and structural history and subsequent change of Cu nanoparticles and with that a deep insight into the reconstruction events. With this evidence, we could interpret the observed structural changes as two separate electrochemical processes occurring one after another, namely copper dissolution from pre‐oxidized native nanoparticles and subsequent (electro‐) redeposition of the dissolved copper species in a form of new smaller Cu fragments.
Kinetic Data for Continuous Processes from Liquid‐Liquid Loop Reactor Experiments
Authors: Rütti David P. , Moser Marlies , Georg Alain G. , Spier Eyal S. , Meier Daniel M.
Published: May 2021

Process engineering is based on models, which are preferably established at laboratory scale under near‐service conditions. Here, for the first time, a kinetic study of the basic hydrolysis of ethyl acetate was performed with a small volume liquid‐liquid loop reactor satisfying these criteria. The activation energy and pre‐exponential factor were determined that agreed with data from the literature. Acquired data could be successfully transferred to well‐established ideal reactor models such as continuous stirred tank or plug flow reactors. It was, thus, possible to show that a simply scalable loop reactor, requiring only small amounts of substrate and producing minimum waste, can serve as a tool for kinetic studies of continuous processes.
Controlled Synthesis of Porous Hollow Fe–N/C Nanoshells as High‐Performance Oxygen Reduction Reaction Electrocatalysts for Zn–Air Battery
Authors: Lin Hua , Chen Jiande , Wu Yijin , Hu Yiyang , Li Yuyang , Li Jun-Tao , Zhou Yao
Published: May 2021

The development of high‐performance non‐noble oxygen reduction reaction (ORR) electrocatalysts is of significant importance for fuel cells and zinc–air batteries. Herein, a dual‐template‐assisted polymerization process is designed using both silica submicrospheres and ultrafine nanoparticles as hard templates, generating permeable hollow benzoxazine resin nanoshells with well‐controlled morphology and size; such resin nanoshells impregnated with urea and iron precursor salt are then calcined under different atmospheres and temperatures to produce a series of porous hollow Fe–N/C thin nanoshells with differentiated pore structures and various N compositions. The effects of the calcination atmosphere and temperature on the structure and composition of the Fe–N/C materials are also evaluated. Owing to its compositional and structural merits, the optimal porous Fe–N/C nanoshell with a specific surface area as high as 998.0 m2 g−1 exhibits a half‐wave potential E1/2 of 0.919 V (vs reversible hydrogen electrode (RHE)) in 0.1 m KOH, 37 mV more positive than that of the commercial Pt/C; when used as a cathode in a Zn–air battery, it displays a power density and specific energy density of 93.5 mW cm−2 and 779.7 mAh gZn−1, respectively. This work provides a straightforward method for the size‐ and shape‐controllable synthesis of Fe–N–C‐based ORR electrocatalysts.
Comprehensive analysis of Syk gene methylation in colorectal cancer
Authors: Bu Fanqin , Zhu Xiaojian , Liu Sicheng , Lin Kang , Zhu Jinfeng , Huang Jun
Published: May 2021

Background: Metastasis of colorectal cancer (CRC) extremely affects the prognosis of CRC patients. Recently, the genetic methylation has been shown to associate with tumor metastasis. This research aimed to explore the Syk gene, which is frequently hypermethylated in different cancers, and its impact on the metastasis of CRC cells.

Methods: We employed the UALCAN database for the detection of the methylation levels of Syk in different cancers. CIBERSORT, TIMER and TISIDB tools were employed to analyze the association of Syk expression with immune features of CRC. Treatment with decitabine has been noted to restore the expression of Syk in CRC cells. The invasion and migration abilities of CRC cell lines were determined using transwell and wound healing assays. The correlation between Syk and c‐Myc was established using the GEPIA2 database and Western blot assays.

​Results: Our results, based on UALCAN, revealed that the methylation level of Syk was altered in diverse cancers including colon adenocarcinoma. We found that expression profile and methylation level of Syk was correlated with immune features of colon adenocarcinoma. Decitabine can restore the expression of Syk in HCT116 and SW480 cells, hence affecting their migration and invasion. Results from GEPIA2 showed that Syk expression was correlated with c‐Myc, while Western blotting analysis revealed a negative association between the expression level of Syk and c‐Myc.

​Conclusions:​ ​This study demonstrates that the expression of Syk could be restored by decitabine in colorectal cancer, thus affecting the migration and invasion abilities of CRC cells.
Maintaining intensive agriculture overlying aquifers using the threshold nitrate root‐uptake phenomenon
Authors: Kurtzman Daniel , Kanner Beeri , Levy Yehuda , Nitsan Ido , Bar‐Tal Asher
Published: May 2021

Reducing nitrate leaching from agricultural land to aquifers has been a high priority concern for more than a half century. This study presents theory and observations of a threshold concentration of nitrate in the root zone (Cmax), which the leachate concentration increases at higher rates with increasing root‐zone nitrate concentration. The value of Cmax is derived both by direct results from container experiments with varying nitrogen (N) fertigation and as a calibration parameter in N‐transport models beneath commercial agricultural plots. For five different crops, Cmax ranged between 20 and 45 mg L−1 of NO3–N derived from experiments and models. However, for lettuce (Lactuca sativa L.), which was irrigated with a large leaching fraction, Cmax could not be defined. In crops irrigated and fertilized in the warm/dry season (corn [Zea mays L.] and citrus), the experiments show a dramatic change in leachate‐concentration slope, and simulations reveal a wide range of sensitivity of leachate NO3–N concentration to Cmax. In annual crops irrigated and fertilized in the cool/wet season (e.g., potato [Solanum tuberosum L.] in a Mediterranean climate), the experiments show a distinct Cmax that is less dramatic than that of the summer‐irrigated crops in the container experiment and a smaller impact of Cmax in N‐transport models. The simulations show that, for summer‐irrigated crops, maintaining fertigation at C < Cmax has a significant effect reducing deep leachate concentrations, whereas for the winter annual crops the simulations revealed no threshold effect. It is suggested that for summer‐irrigated crops, fertigation below Cmax robustly serves the co‐sustainability of intensive agriculture and aquifer water quality; this is also suggested for winter crops, but the benefits are not robust. For short‐season, small root‐system crops (e.g., lettuce), efforts should be made to detach the crop from the soil.
Nečas–Lions lemma revisited: An Lp‐version of the generalized Korn inequality for incompatible tensor fields
Authors: Lewintan Peter , Neff Patrizio
Published: May 2021

For 1 < p < ∞, we prove an Lp‐version of the generalized Korn inequality for incompatible tensor fields P in
. More precisely, let
be a bounded Lipschitz domain. Then there exists a constant c = c(p, Ω) > 0 such that

holds for all tensor fields
, that is, for all
with vanishing tangential trace
on ∂Ω where ν denotes the outward unit normal vector field to ∂Ω. For compatible
, this recovers an Lp‐version of the classical Korn's first inequality and for skew‐symmetric
an Lp‐version of the Poincaré inequality.
Scale‐adaptive deep network for deformable image registration
Authors: Sang Yudi , Ruan Dan
Published: May 2021

Purpose

Multiresolution hierarchical strategy is typically used in conventional optimization‐based image registration to capture varying magnitudes of deformations while avoiding undesirable local minima. A rough concept of the scale is captured in deep networks by the reception field of kernels, and it has been realized to be both desirable and challenging to capture convolutions of different scales simultaneously in registration networks. In this study, we propose a registration network that is conscious of and self‐adaptive to deformation of various scales to improve registration performance.

Methods

Dilated inception modules (DIMs) are proposed to incorporate receptive fields of different sizes in a computationally efficient way. Scale adaptive modules (SAMs) are proposed to guide and adjust shallow features using convolutional kernels with spatially adaptive dilation rate learned from deep features. DIMs and SAMs are integrated into a registration network which takes a U‐net structure. The network is trained in an unsupervised setting and completes registration with a single evaluation run.

Results

Experiment with two‐dimensional (2D) cardiac MRIs showed that the adaptive dilation rate in SAM corresponded well to the deformation scale. Evaluated with left ventricle segmentation, our method achieved a Dice coefficient of (0.93 ± 0.02), significantly better than SimpleElastix and networks without DIM or SAM. The average surface distance was less than 2 mm, comparable to SimpleElastix without statistical significance. Experiment with synthetic data demonstrated the effectiveness of DIMs and SAMs, which led to a significant reduction in target registration error (TRE) based on dense deformation field. The three‐dimensional (3D) version of the network achieved a 2.52 mm mean TRE on anatomical landmarks in DIR‐Lab thoracic 4DCTs, lower than SimpleElastix and networks without DIM or SAM with statistical significance. The average registration times were 0.002 s for 2D images with size 256 × 256 and 0.42 s for 3D images with size 256 × 256 × 96.

Conclusions

The introduction and integration of DIMs and SAMs addressed the heterogeneous scale problem in an efficient and self‐adaptive way. The proposed method provides an alternative to the inefficient multiresolution registration setups.
Phase contrast coronary blood velocity mapping with both high temporal and spatial resolution using triggered Golden Angle rotated Spiral k‐t Sparse Parallel imaging (GASSP) with shifted binning
Authors: Zhu Dan , Bonanno Gabriele , Hays Allison G. , Weiss Robert G. , Schär Michael
Published: May 2021

Purpose

High temporal and spatial resolutions are required for coronary blood flow measures. Current spiral breath‐hold phase contrast (PC) MRI at 3T focus on either high spatial or high temporal resolution. We propose a golden angle (GA) rotated Spiral k‐t Sparse Parallel imaging (GASSP) sequence for both high spatial (0.8 mm) and high temporal (<21 ms) resolutions.

Methods

GASSP PC data are acquired in left anterior descending and right coronary arteries of eight healthy subjects. Binning of GA rotated spiral data into cardiac frames may lead to large k‐space gaps. To reduce those gaps, the binning window is shifted and a triggered GA scheme that resets the rotation angle every heartbeat is proposed. The gap reductions are evaluated in simulations and all subjects. Peak systolic velocity (PSV), peak diastolic velocity (PDV), coronary blood flow rate, and vessel area are validated against two reference scans, and repeatability/reproducibility are determined.

Results

Shifted binning reduced the mean k‐space gaps of the triggered GA scheme by 14°‐22° in simulations and about 20° in vivo. The k‐space gap across three cardiac frames was reduced with the triggered GA scheme compared to the standard GA scheme (35.3°± 3.6° vs. 43°± 13.7°, t‐test P = .04). PSV, PDV, flow rate, and area had high intra‐scan repeatability (0.92 ≤ intraclass correlation coefficient [ICC] ≤ 0.99), and inter‐scan (0.78 ≤ ICC ≤ 0.91) and intra‐observer (0.91 ≤ ICC ≤ 0.98) reproducibility.

Conclusion

GASSP enables single breath‐hold coronary PC MRI with high temporal and spatial resolutions. Shifted binning and a triggered GA scheme reduce k‐space gaps. Quantitative coronary flow metrics are highly reproducible, especially within the same scanning session.
Soft segment‐free functional polyurethane: A versatile candidate for heat‐healability, non‐dissociative mechanism, and high elongation adhesive materials
Authors: Edachery Veetil Rashmi , Vijayalakshmi Kunduchi Periya , Srinivas Chinthalapalli , Mathew Dona , Kalamblayil Sankaranarayanan Santhosh Kumar
Published: May 2021

Functional and re‐processable polyurethane (soft‐segment free, FPU) is synthesized and later it is converted into substituted PUs by reaction with suitable molecules to enrich/block H‐bonding features inherent with FPU. By these substitutions, H‐bonding is easily altered as observed in FTIR investigations. Spherical morphology of FPU turned into elongated/twisted one due to the separation of polymer chains by these molecules (bulky or long chain groups). Owing to the presence of hydroxyl groups, the dissociation of FPU on re‐processing at 150°C was dodged and achieved heat‐healable PUs. Interestingly, a trivial quantity (2.5 wt%) of FPU in an epoxy‐amine cross‐linked structure increased the elongation to nearly fourfold (5%‐21%). The soft‐segment free nature of PU and its functional groups have key role in facilitating easy incorporation of PU into epoxy matrices to provide exotic properties.
Principled selection of baseline covariates to account for censoring in randomized trials with a survival endpoint
Authors: Van Lancker Kelly , Dukes Oliver , Vansteelandt Stijn
Published: May 2021

The analysis of randomized trials with time‐to‐event endpoints is nearly always plagued by the problem of censoring. In practice, such analyses typically invoke the assumption of noninformative censoring. While this assumption usually becomes more plausible as more baseline covariates are being adjusted for, such adjustment also raises concerns. Prespecification of which covariates will be adjusted for (and how) is difficult, thus prompting the use of data‐driven variable selection procedures, which may impede valid inferences to be drawn. The adjustment for covariates moreover adds concerns about model misspecification, and the fact that each change in adjustment set also changes the censoring assumption and the treatment effect estimand. In this article, we discuss these concerns and propose a simple variable selection strategy designed to produce a valid test of the null in large samples. The proposal can be implemented using off‐the‐shelf software for (penalized) Cox regression, and is empirically found to work well in simulation studies and real data analyses.
Electrochemically Induced Phase Transition in V3O7 · H2O Nanobelts/Reduced Graphene Oxide Composites for Aqueous Zinc‐Ion Batteries
Authors: Cao Huili , Zheng Zhiyong , Norby Poul , Xiao Xinxin , Mossin Susanne
Published: May 2021

V3O7·H2O nanobelts/reduced graphene oxide (rGO) composites (weight ratio: 86%/14%) are synthesized by a microwave approach with a high yield (85%) through controlling pH with acids. The growth mechanisms of the highly crystalline nanobelts (average diameter: 25 nm; length: ≈20 µm; oriented along the [101] direction) have been thoroughly investigated, with the governing role of the acid upon the morphology and oxidation state of vanadium disclosed. When used as the ZIB cathode, the composite can deliver a high specific capacity of 410.7 and 385.7 mAh g−1 at the current density of 0.5 and 4 A g−1, respectively, with a high retention of the capacity of 93%. The capacity of the composite is greater than those of V3O7 · H2O, V2O5 nanobelts, and V5O12 · 6H2O film. Zinc ion storage in V3O7·H2O/rGO is mainly a pseudocapacitive behavior rather than ion diffusion. The presence of rGO enables outstanding cycling stability of up to 1000 cycles with a capacity retention of 99.6%. Extended cycling shows a gradual phase transition, that is, from the original orthorhombic V3O7 · H2O to a stable hexagonal Zn3(VO4)2(H2O)2.93 phase, which is a new electrochemical route found in V3O7 materials. This phase transition process provides new insight into the reactions of aqueous ZIBs.
Transient thermoelastic response of a size‐dependent nanobeam under the fractional order thermoelasticity
Authors: Peng Wei , Ma Yongbin , He Tianhu
Published: May 2021

With the miniaturization of structures, such as MEMS/NEMS, the size‐dependent effect has become an issue and attracted much attention. The well‐known theories describing the size‐dependent effect mainly include the nonlocal elasticity theory, the strain gradient theory and the modified coupled stress theory. Based on these theories, a number of works have been conducted to explore the size‐dependent behaviors of structures or devices in micro/nano‐scale, among them, majorities are on elastic performances, while, minorities are on thermoelastic performances. It is inevitable for structures suffering changeable temperature, as a consequence, thermal‐induced stress and deformation occur in structures and they are worth being fully concerned. For thermoelastic behaviors limited to small scale problems, the classical Fourier's heat conduction law may fail, meanwhile, new models, for example, fractional order heat conduction model, have been developed to modify Fourier's law. In present paper, the transient thermoelastic response of a nanobeam subjected to a ramp heating is investigated by combining the nonlocal elasticity theory and the fractional order heat conduction model. The governing equations are formulated and then solved by Laplace transform and its numerical inversion. The non‐dimensional temperature, displacement, stress, and deflection in the nanobeam are obtained and illustrated graphically. In calculation, the effects of the ramp‐heating time parameter, the nonlocal parameter and the fractional order parameter on the considered physical quantities are examined and discussed in detail.
Non-singular black holes with a zero-shear S-brane
Authors: Brandenberger Robert , Heisenberg Lavinia , Robnik Jakob
Published: May 2021

Abstract

We propose a construction with which to resolve the black hole singularity and enable an anisotropic cosmology to emerge from the inside of the hole. The model relies on the addition of an S-brane to the effective action which describes the geometry of space-time. This space-like defect is located inside of the horizon on a surface where the Weyl curvature reaches a limiting value. We study how metric fluctuations evolve from the outside of the black hole to the beginning of the cosmological phase to the future of the S-brane. Our setup addresses i) the black hole singularity problem, ii) the cosmological singularity problem and iii) the information loss paradox since the outgoing Hawking radiation is entangled with the state inside the black hole which becomes the new universe.
What Is the Role of Assessing Ischemia to Optimize Therapy and Outcomes for Patients with Stable Angina and Non-obstructed Coronary Arteries?
Authors: Berry Colin , Morrow Andrew J. , Marzilli Mario , Pepine Carl J.
Published: May 2021

Ischemic heart disease (IHD) is a leading global cause of ill-health and premature death. Clinical research into IHD is providing new insights into the pathophysiology, epidemiology and treatment of this condition. The major endotypes of IHD include coronary heart disease (CHD) and vasomotor disorders, including microvascular angina and vasospastic angina. Considering unselected patients presenting with stable chest pain, the pre-test probability of CHD is higher in men whereas the pre-test probability of a vasomotor disorder is higher in women. The diagnostic accuracy of diagnostic tests designed to assess coronary anatomy and disease and/or coronary vascular function (functional tests) differ for coronary endotypes. Clinical management should therefore be personalized and take account of sex-related factors. In this review, we consider the definitions of angina and myocardial ischemia. We then appraise the mechanistic links between myocardial ischemia and anginal symptoms and the relative merits of non-invasive and invasive diagnostic tests and related clinical management. Finally, we describe the rationale and importance of stratified medicine of IHD.
Random Assignment Problems on 2d Manifolds
Authors: Benedetto D. , Caglioti E. , Caracciolo S. , D’Achille M. , Sicuro G. , Sportiello A.
Published: May 2021

We consider the assignment problem between two sets ofNrandom points on a smooth, two-dimensional manifold$$\Omega $$Ωof unit area. It is known that the average cost scales as$$E_{\Omega }(N)\sim {1}/{2\pi }\ln N$$EΩ(N)∼1/2πlnNwith a correction that is at most of order$$\sqrt{\ln N\ln \ln N}$$lnNlnlnN. In this paper, we show that, within the linearization approximation of the field-theoretical formulation of the problem, the first$$\Omega $$Ω-dependent correction is on the constant term, and can be exactly computed from the spectrum of the Laplace–Beltrami operator on$$\Omega $$Ω. We perform the explicit calculation of this constant for various families of surfaces, and compare our predictions with extensive numerics.
Inverse reinforcement learning in contextual MDPs
Authors: Belogolovsky Stav , Korsunsky Philip , Mannor Shie , Tessler Chen , Zahavy Tom
Published: May 2021

We consider the task of Inverse Reinforcement Learning in Contextual Markov Decision Processes (MDPs). In this setting, contexts, which define the reward and transition kernel, are sampled from a distribution. In addition, although the reward is a function of the context, it is not provided to the agent. Instead, the agent observes demonstrations from an optimal policy. The goal is to learn the reward mapping, such that the agent will act optimally even when encountering previously unseen contexts, also known as zero-shot transfer. We formulate this problem as a non-differential convex optimization problem and propose a novel algorithm to compute its subgradients. Based on this scheme, we analyze several methods both theoretically, where we compare the sample complexity and scalability, and empirically. Most importantly, we show both theoretically and empirically that our algorithms perform zero-shot transfer (generalize to new and unseen contexts). Specifically, we present empirical experiments in a dynamic treatment regime, where the goal is to learn a reward function which explains the behavior of expert physicians based on recorded data of them treating patients diagnosed with sepsis.
BMP4 and PHLDA1 are plausible drug-targetable candidate genes for KRAS G12A-, G12D-, and G12V-driven colorectal cancer
Authors: Ohnami Shumpei , Maruyama Kouji , Chen Kai , Takahashi Yu , Hatakeyama Keiichi , Ohshima Keiichi , Shimoda Yuji , Sakai Ai , Kamada Fukumi , Nakatani Sou , Naruoka Akane , Ohnami Sumiko , Kusuhara Masatoshi , Akiyama Yasuto , Kagawa Hiroyasu , Shiomi Akio , Nagashima Takeshi , Urakami Kenichi , Yamaguchi Ken
Published: May 2021

Despite the frequent detection of KRAS driver mutations in patients with colorectal cancer (CRC), no effective treatments that target mutant KRAS proteins have been introduced into clinical practice. In this study, we identified potential effector molecules, based on differences in gene expression between CRC patients carrying wild-type KRAS (n = 390) and those carrying KRAS mutations in codon 12 (n = 240). CRC patients with wild-type KRAS harboring mutations in HRAS, NRAS, PIK3CA, PIK3CD, PIK3CG, RALGDS, BRAF, or ARAF were excluded from the analysis. At least 11 promising candidate molecules showed greater than two-fold change between the KRAS G12 mutant and wild-type and had a Benjamini-Hochberg-adjusted P value of less than 1E-08, evidence of significantly differential expression between these two groups. Among these 11 genes examined in cell lines transfected with KRAS G12 mutants, BMP4, PHLDA1, and GJB5 showed significantly higher expression level in KRAS G12A, G12D, and G12V transfected cells than in the wild-type transfected cells. We expect that this study will lead to the development of novel treatments that target signaling molecules functioning with KRAS G12-driven CRC.
Premature consent and patient duties
Authors: Rebera Andrew P. , Dimitriou Dimitris
Published: May 2021

This paper addresses the problem of ‘premature consent’. The term ‘premature consent’ (introduced in a 2018 paper by J.K. Davis) denotes patient decisions that are: (i) formulated prior to discussion with the appropriate healthcare professional (HCP); (ii) based on information from unreliable sources (e.g. parts of the internet); and (iii) resolutely maintained despite the HCP having provided alternative reliable information. HCPs are not obliged to respect premature consent patients’ demands for unindicated treatments. But why? What is it that premature consent patients do or get wrong? Davis has argued that premature consent patients are incompetent and misinformed. We argue that this view is not sustainable. A more plausible position asserts that premature consent threatens the integrity of the medical profession. We argue that this gives rise to a negative patient duty (to not obstruct HCPs in upholding the integrity of the medical profession) which premature consent patients fail to honour. We argue for a further positive duty of good faith engagement in shared decision-making. This implies willingness to potentially revise or justify one’s evaluative bases (core assumptions, beliefs, values, etc.). Fundamentally, the problem with premature consent patients is that certain of their evaluative bases are not open to revision. They therefore fail in their duty to participate faithfully in the shared decision-making process.
On the use of evolutionary mismatch theories in debating human prosociality
Authors: Segovia-Cuéllar Andrés , Del Savio Lorenzo
Published: May 2021

According to some evolutionary theorists human prosocial dispositions emerged in a context of inter-group competition and violence that made our psychology parochially prosocial, ie. cooperative towards in-groups and competitive towards strangers. This evolutionary hypothesis is sometimes employed in bioethical debates to argue that human nature and contemporary environments, and especially large-scale societies, are mismatched. In this article we caution against the use of mismatch theories in moral philosophy in general and discuss empirical evidence that puts into question mismatch theories based on parochial prosociality. Evolutionary mismatch theories play at best a rhetorical role in these moral debates and may misrepresent the status of relevant evolutionary research. We finally recommend that moral philosophers interested in the evolutionary literature also engage with dispositions such as xenophilia and social tolerance to counterbalance the focus on psychological mismatches adopted so far.
Tracking control for underactuated non-minimum phase multibody systems
Authors: Berger Thomas , Drücker Svenja , Lanza Lukas , Reis Timo , Seifried Robert
Published: May 2021

We consider tracking control for multibody systems which are modeled using holonomic and non-holonomic constraints. Furthermore, the systems may be underactuated and contain kinematic loops and are thus described by a set of differential-algebraic equations that cannot be reformulated as ordinary differential equations in general. We propose a control strategy which combines a feedforward controller based on the servo-constraints approach with a feedback controller based on a recent funnel control design. As an important tool for both approaches, we present a new procedure to derive the internal dynamics of a multibody system. Furthermore, we present a feasible set of coordinates for the internal dynamics avoiding the effort involved with the computation of the Byrnes–Isidori form. The control design is demonstrated by a simulation for a nonlinear non-minimum phase multi-input, multi-output robotic manipulator with kinematic loop.