bluuebunny/crossref_metadata_2025 huggingface dataset:
The association of viral load and disease severity in children with COVID‐19
Authors: Aykac Kubra , Cura Yayla Burcu Ceylan , Ozsurekci Yasemin , Evren Kubra , Oygar Pembe Derin , Gurlevik Sibel Lacinel , Coskun Tugce , Tasci Onur , Demirel Kaya Filiz , Fidanci Ilknur , Tasar Medine Aysin , Alp Alpaslan , Cengiz Ali Bulent , Karahan Sevilay , Ceyhan Mehmet
Published: February 2021

It is still not fully understood how to predict the future prognosis of patients at the diagnosis coronavirus disease 2019 (COVID‐19) due to the wide clinical range of the disease. We aimed to evaluate whether severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) viral load could predict the clinical course of pediatric patients. This study was conducted retrospectively with medical records of pediatric patients who were tested for SARS‐CoV2 between April 12 and October 25, 2020 in the University of Health Sciences, Ankara Educating and Training Hospital and Hacettepe University Faculty of Medicine. We evaluated 518 pediatric patients diagnosed with COVID‐19 and classified according to severity as asymptomatic (16.2%), mild (59.6%), moderate (20.2%), and critical/severe (3.9%) cases. We analyzed patients in four groups in terms of ages: <4, 5‐9, 10–14, and 15–17 years. There was no statistically significant difference in terms of ∆Ct value among age groups, different gender and the existence of underlying diseases in each disease course. The ∆Ct values were relatively lower in the first 2 days of symptoms than after days in all groups. Our study has indicated that children with COVID‐19 have similar amount of viral load in all disease courses irrespective of the age and underlying disease. It should be taken into account that, regardless of the severity of the disease, pediatric patients may have a role in the transmission chain.
Extracting data from graphs: A case‐study on animal research with implications for meta‐analyses
Authors: Van der Mierden Stevie , Spineli Loukia Maria , Talbot Steven R. , Yiannakou Christina , Zentrich Eva , Weegh Nora , Struve Birgitta , Zur Brügge Talke Friederike , Bleich André , Leenaars Cathalijn H.C.
Published: February 2021

Systematic reviews with meta‐analyses are powerful tools that can answer research questions based on data from published studies. Ideally, all relevant data is directly available in the text or tables, but often it is only presented in graphs. In those cases, the data can be extracted from graphs, but this potentially introduces errors. Here, we investigate to what extent the extracted outcome and error values differ from the original data and if these differences could affect the results of a meta‐analysis. Six extractors extracted 36 outcome values and corresponding errors from 22 articles. Differences between extractors were compared using overall concordance correlation coefficients (OCCC), differences between the original and extracted data were compared using concordance correlation coefficients (CCC). To test the possible influence on meta‐analyses, random‐effects meta‐analyses on mean difference comparing original and extracted data were performed. The OCCCs and CCCs were high for both outcome values and errors, CCCs were >0.99 for the outcome and >0.92 for errors. The meta‐analyses showed that the overall effect on outcome was very small (median: 0.025, interquartile range: 0.016–0.046). Therefore, data extraction from graphs is a good method to harvest data if it is not provided in the text or tables, and the original authors cannot provide the data.
Factors that Determine Human Acceptance of Black Bears
Authors: Cleary Matteo , Joshi Omkar , Fairbanks W. Sue
Published: February 2021

After being extirpated from their historical distribution, black bears (Ursus americanus) have recolonized eastern Oklahoma, USA. As bears continue to establish populations in the region, understanding the cognitive factors that influence human acceptance of black bears will play an important role in facilitating coexistence. We hypothesized that a variety of variables drawing from the cognitive hierarchy and risk perception frameworks would affect human acceptance of black bears in eastern Oklahoma. We collected data using a mail‐back questionnaire administered to residents of eastern Oklahoma between August and November 2018. Perceptions of the current black bear population size, attitudes toward bears, valuing Oklahoma wildlife, behavioral intentions, and level of formal education all positively influenced acceptance of bears. Risk‐averse respondents and women were less accepting. Outreach to women and encouraging residents to reduce conflict by adopting bear‐safe behaviors may help raise acceptance capacity for black bears. © 2021 The Wildlife Society.
Long‐Term Evaluation of Cougar Density and Application of Risk Analysis for Harvest Management
Authors: Beausoleil Richard A. , Welfelt Lindsay S. , Keren Ilai N. , Kertson Brian N. , Maletzke Benjamin T. , Koehler Gary M.
Published: February 2021

Estimates of cougar (Puma concolor) density are among the least available of any big game species in North America because of monetary and logistical challenges. Thus, wildlife managers identify cougar density estimates as a high priority need for population estimation, developing harvest guidelines, and evaluating management objectives. Cougar densities range from <1 to almost 7 cougars/100 km2; however, the magnitude of spatial and temporal variation associated with these estimates is difficult to assess because this range of densities could potentially be reported for any given population using different demographic, temporal, durational, and analytical approaches. We used long‐term global positioning system (GPS) data from collared cougars across 5 diverse study areas in Washington, USA, as the basis for calculating multiple annual independent‐aged (≥18 months) cougar densities, using consistent methods, and conducted a meta‐analysis to assist with statewide harvest guidelines. To generate specific harvest guidelines for unobserved populations at the management unit scale, we employed a Bayesian decision‐theoretic approach that minimizes statistical risk of failing to achieve a defined harvest rate. For the 16‐year field effort, we calculated 24 annual densities for independent‐aged cougars. Average annual densities ranged from 1.55 ± 0.44 (SD) cougars/100 km2 (n = 5 years) to 2.79 ± 0.35 cougars/100 km2 (n = 5 years) among the 5 study areas. Explicit delineation of the cougar population demonstrated that contribution to density can vary considerably by sex and age class. Application of a 12–16% harvest rate within the risk analysis framework yielded a potential annual harvest of 249 cougars over 91,000 km2 of cougar habitat in Washington. Given the importance of density for establishing harvest guidelines, and the degree of uncertainty in projecting derived densities to future years and unstudied management units, our approach may lessen the ambiguity of extrapolations and increase the longevity of research results. Our risk analysis can be used for a diverse array of species and management objectives and be incorporated into an adaptive management framework for minimizing management risk. Our recommendations can improve standardization in reporting and interpretation of cougar density comparisons and bring clarity to the sources of variability observed in cougar populations. © 2021 The Wildlife Society.
Determination of Retronasal Olfactory Threshold Values
Authors: Özay Hüseyin , Çetin Aslı Çakır , Ecevit Mustafa Cenk
Published: February 2021

Objectives/Hypothesis

The aim of this study was to generate normative data of retronasal olfactory threshold values for normosmic and hyposmic individuals and to test the validity of that data by determining the discriminative power for normosmic/hyposmic differentiation.

Study Design

Prospective, descriptive and methodological study.

Methods

The orthonasal olfactory function of 20 normosmic and 20 hyposmic cases was evaluated using the Sniffin' Sticks Olfactory test. Sniffin' Sticks odor threshold, odor discrimination, and odor identification values and threshold discrimination identification (TDI) scores were recorded. A 13‐item test battery previously prepared in our Rhinology Laboratory for retronasal olfactory threshold test that consisted of concentrated solutions prepared from 2:1 diluted 99% phenylethyl alcohol (PEA) and water was used. Each concentration was evaluated with water control, and if not answered correctly, the same process was continued by moving to a higher concentration series. Four consecutive correct answers were determined as the patient's retronasal olfactory threshold.

Results

A strong correlation was found between Sniffin' Sticks TDI scores and retronasal odor threshold values in the normosmic group (P < .001, r:0.67). A very strong correlation was found between Sniffin' Sticks TDI scores and retronasal olfactory threshold values in the hyposmic group (P < .001, r:0.81). Furthermore, receiver operating characteristic (ROC) analysis revealed that the sensitivity and the specificity of normosmic/hyposmic differentiation of retronasal olfactory threshold test was 95% and 100%, respectively. The diagnostic cutoff value was 8.5.

Conclusions

This study shows that the retronasal olfactory test, a psychophysical odor test performed using an orally presented stimulus, can be used to differentiate normosmic and hyposmic cases.

Level of Evidence

3 Laryngoscope, 131:1608–1614, 2021
Fractional 1064 nm Picosecond Laser in Treatment of Melasma and Skin Rejuvenation in Asians, A Prospective Study
Authors: Wong Christina S. M , Chan Mandy W. M , Shek Samantha Y. N , Yeung Chi Keung , Chan Henry H. L
Published: February 2021

Background and Objectives

Facial melasma is a disfiguring pigmentation and occurs frequently with aging skin. Topical treatment alone was often suboptimal. A recent study showed that fractional picosecond laser has promising result in benign pigmentary lesions. This study aims to investigate the efficacy and safety of 1064 nm picosecond laser in treatment of facial melasma and skin rejuvenation in Asian skin.

Study Design/Materials and Methods

Patients of Asian descent seeking treatment for facial melasma and skin rejuvenation were screened and recruited. Each patient received up to nine laser treatments at 4–6 weeks intervals with a fractionated nonablative 1064 nm picosecond laser. Baseline and posttreatment modified Melasma Area Severity Index (mMASI) and Global Aesthetic Improvement Scale (IGAS) were assessed by blinded investigators based on the clinical photographs. Subject overall satisfaction was assessed by the questionnaires after treatment. All adverse events were documented.

Results

Twenty patients were recruited with a median age of 52.7 ± 8.2 years. Three subjects had Fitzpatrick skin type III and 17 had skin type IV. All subjects received nine laser sessions. Over 70% of patients were satisfied with the treatment outcomes. There was a statistically significant improvement in mMASI which reduced from 10.8 at baseline to 2.7 and 3.6 at 6 and 12 weeks post‐treatment, respectively (both P < 0.01). For skin rejuvenation, 70% reported at least a moderate improvement at 6 weeks of post‐treatment. No major side‐effect was reported. Erythema was the most frequent transient response, while some reported edema (1.1%). Both resolved spontaneously. None reported hypo‐ or hyperpigmentation after treatment. The overall mean pain scare (VAS) was 1.92.

Conclusion

Fractionated non‐ablative 1064 nm picosecond laser was effective in treatment of melasma and skin rejuvenation. It was also safe and well tolerated. Importantly, there was no hypo or hyperpigmentation reported. Lasers Surg. Med. 00:00–00, 2021. © 2021 Wiley Periodicals LLC
Study of corrosion inhibition properties of Schinus molle essential oil on carbon steel in HCl
Authors: Mellak Nadjat , Ghali Noureddine , Messaoudi Nadia , Benhelima Abdelkader , Ferhat Mahmoud , Addou Ahmed
Published: February 2021

The inhibitory action of Schinus molle L. essential oil was investigated for the corrosion of carbon steel in 1 M hydrochloric acid solution using weight loss, polarization curves, and electrochemical impedance spectroscopy. The inhibition efficiency has increased with the increase of the inhibitor concentration, reaching a value of up to 70% at 2 g/L.
Recent Advances on Fabrication of Polymeric Composites Based on Multicomponent Reactions for Bioimaging and Environmental Pollutant Removal
Authors: Yang Guang , Liang Jie , Hu Xin , Liu Meiying , Zhang Xiaoyong , Wei Yen
Published: February 2021

As the core of polymer chemistry, manufacture of functional polymers is one of research hotspots over the past several decades. Various polymers are developed for diverse applications due to their tunable structures and unique properties. However, traditional step‐by‐step preparation strategies inevitably involve some problems, such as separation, purification, and time‐consuming. The multicomponent reactions (MCRs) are emerging as environmentally benign synthetic strategies to construct multifunctional polymers or composites with pendant groups and designed structures because of their features, such as efficient, fast, green, and atom economy. This mini review summarizes the latest advances about fabrication of multifunctional fluorescent polymers or adsorptive polymeric composites through different MCRs, including Kabachnik–Fields reaction, Biginelli reaction, mercaptoacetic acid locking imine reaction, Debus–Radziszewski reaction, and Mannich reaction. The potential applications of these polymeric composites in biomedical and environmental remediation are also highlighted. It is expected that this mini‐review will promote the development preparation and applications of functional polymers through MCRs.
Seasonal variation of viral infections between the eastern honey bee (Apis cerana) and the western honey bee (Apis mellifera)
Authors: Chen Gongwen , Wu Yuqi , Deng Jie , Wen Zhengsheng , Wang Shuai , Chen Yanping , Hu Fuliang , Zheng Huoqing
Published: February 2021

It is a widespread practice in China to keep colonies of both the western honey bee, Apis mellifera, and the eastern honey bee, Apis cerana, in close proximity. However, this practice increases opportunities for spillover of parasites and pathogens between the two host bee species, impacting spatial and temporal patterns in the occurrence and prevalence of the viruses that adversely affect bee health. We conducted a 1‐year large‐scale survey to assess the current status of viral infection in both A. mellifera and A. cerana in China. Our study focused on multiple aspects of viral infections in honey bees, including infection rate, viral load, seasonal variation, regional variation, and phylogenetic relationships of the viruses within the same species found in this study and other parts of the world. The survey showed that the black queen cell virus (BQCV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV) were common in both A. mellifera and A. cerana, and infection dynamics of BQCV, DWV, and SBV between bee species or seasons were significantly different. DWV was the most common virus in A. mellifera, and its infection rate and load in A. mellifera were higher than those in A. cerana, which reflects the high susceptibility of A. mellifera to Varroa destructor infestation. The infection rate and viral load of SBV were higher in A. cerana than in A. mellifera, indicating that SBV poses a greater threat to A. cerana than to A. mellifera. Our results also suggested that there was no geographical variation in viral dynamics in A. mellifera and A. cerana. Phylogenetic analyses of BQCV, DWV, IAPV, and SBV suggested the cross‐regional and cross‐species spread of these viruses. This study provides important insights into the complex relationships between viruses and their hosts in different seasons and regions, which will be important for developing effective disease management strategies to improve bee health.
IL‐6 and IL‐8, secreted by myofibroblasts in the tumor microenvironment, activate HES1 to expand the cancer stem cell population in early colorectal tumor
Authors: Kim Bun , Seo Yoojeong , Kwon Ji‐Hee , Shin Youmi , Kim Suhyun , Park Soo Jung , Park Jae Jun , Cheon Jae Hee , Kim Won Ho , Il Kim Tae
Published: February 2021

Interaction between a tumor and its microenvironment is important for tumor initiation and progression. Cancer stem cells (CSCs) within the tumor interact with a microenvironmental niche that controls their maintenance and differentiation. We investigated the CSC‐promoting effect of factors released from myofibroblasts into the microenvironment of early colorectal cancer tumors and its molecular mechanism. By messenger RNA microarray analysis, expression of HES1, a Notch signaling target, significantly increased in Caco‐2 cells cocultured with 18Co cells (pericryptal myofibroblasts), compared to its expression in Caco‐2 cells cultured alone. Caco‐2 cells cultured in 18Co‐conditioned media (CM) showed a significant increase in CD133+CD44+ cells and HES1 expression compared to that in Caco‐2 cells cultured in regular media. Significant amounts of interleukin‐6 (IL‐6) and IL‐8 were detected in 18Co‐CM compared to levels in regular media. The 18Co‐CM‐induced increase in CD133+CD44+ cells was attenuated by IL‐6‐ and IL‐8‐neutralizing antibodies. Furthermore, these neutralizing antibodies and inhibitors of STAT3 and gamma‐secretase reduced the expression of HES1 induced in Caco‐2 cells cultured in 18Co‐CM. Immunohistochemical analysis of human tissues revealed that IL‐6, IL‐8, and HES1 expression increased from normal to adenoma, and from adenoma to cancer tissues. In addition, IL‐6 and HES1 expression was positively correlated in early colorectal cancer tissues. In conclusion, the increase of CSCs by myofibroblasts could be mediated by IL‐6/IL‐8‐induced HES1 activation in the tumor microenvironment. Based on these data, the IL‐6/IL‐8‐mediated Notch/HES1 and STAT3 pathway, through which CSCs interact with their microenvironment, might be a potential target for the prevention and treatment of colorectal tumors.
Levodopa Causes Striatal Cholinergic Interneuron Burst‐Pause Activity in Parkinsonian Mice
Authors: Paz Rodrigo Manuel , Tubert Cecilia , Stahl Agostina Monica , Amarillo Yimy , Rela Lorena , Murer Mario Gustavo
Published: February 2021

Background

Enhanced striatal cholinergic interneuron activity contributes to the striatal hypercholinergic state in Parkinson's disease (PD) and to levodopa‐induced dyskinesia. In severe PD, dyskinesia and motor fluctuations become seriously debilitating, and the therapeutic strategies become scarce. Given that the systemic administration of anticholinergics can exacerbate extrastriatal‐related symptoms, targeting cholinergic interneurons is a promising therapeutic alternative. Therefore, unraveling the mechanisms causing pathological cholinergic interneuron activity in severe PD with motor fluctuations and dyskinesia may provide new molecular therapeutic targets.

Methods

We used ex vivo electrophysiological recordings combined with pharmacological and morphological studies to investigate the intrinsic alterations of cholinergic interneurons in the 6‐hydroxydopamine mouse model of PD treated with levodopa.

Results

Cholinergic interneurons exhibit pathological burst‐pause activity in the parkinsonian “off levodopa” state. This is mediated by a persistent ligand‐independent activity of dopamine D1/D5 receptor signaling, involving a cyclic adenosine monophosphate (cAMP) pathway. Dysregulation of membrane ion channels that results in increased inward‐rectifier potassium type 2 (Kir2) and decreased leak currents causes the burst pause activity, which can be dampened by pharmacological inhibition of intracellular cAMP. A single challenge with a dyskinetogenic dose of levodopa is sufficient to induce persistent cholinergic interneuron burst‐pause firing.

Conclusion

Our data unravel a mechanism causing aberrant cholinergic interneuron burst‐pause activity in parkinsonian mice treated with levodopa. Targeting D5‐cAMP signaling and the regulation of Kir2 and leak channels may alleviate parkinsonism and dyskinesia by restoring normal cholinergic interneuron function. © 2021 International Parkinson and Movement Disorder Society
Report: New school funding should bolster MH staffing in Denver
Authors: Enos Gary
Published: February 2021

A Colorado education research and advocacy organization is reporting a spirit of cooperation that it hopes will create progress in correcting shortages of mental health professionals in Denver's public school system.
APA survey: Majority of Americans reporting prolonged stress
Authors: Canady Valerie A.
Published: February 2021

More than 80% of Americans report emotions associated with prolonged stress, and say the country has serious societal issues that need to be addressed, according to a post‐inauguration Stress in America survey released Feb. 2 by the American Psychological Association (APA). Adults are reporting the highest stress levels since the early days of COVID‐19, according to the APA.
Pseudohyperbolic distance and n‐best rational approximation in ℍ2 space
Authors: Wang Yan‐Bo , Qian Tao
Published: February 2021

Through reducing the problem to rational orthogonal system (Takenaka–Malmquist system), this note gives a proof for existence of n‐best rational approximation to functions in the Hardy
space by using pseudohyperbolic distance.
Review on polarimetric terahertz spectroscopy
Authors: Gong Yandong , Zhang Zhuo , Li Ke , Ren Wenxu
Published: February 2021

Unique features of terahertz (THz) wave have made THz spectroscopy a potential and ideal tool for spectroscopy analysis. When a conventional THz spectroscopy system is used to measure a sample with birefringence, sometimes it is highly possible to misinterpret a polarization filter effect as normal spectral absorption, thus leads to a wrong identification and conclusion. Polarimetric terahertz spectroscopy (PTS) is one kind of newly emerged technology upgraded from conventional terahertz spectroscopy, in addition to all the traditional functions, it is able to automatically measure additional state of polarization of THz wave, as well as additional polarization information of samples. Here in this article we will comprehensively review the principle and progress of such PTS technology.
Identification of aluminum alloy by laser‐induced breakdown spectroscopy combined with machine algorithm
Authors: Dai Yujia , Zhao Shangyong , Song Chao , Gao Xun
Published: February 2021

Discarded aluminum alloys are a form of recyclable metal materials, and their classification and identification are highly important. In this work, laser‐induced breakdown spectroscopy (LIBS) technique combined with principal component analysis (PCA) and least‐squares support‐vector machine (LSSVM) algorithm were used to classify and identify five types of aluminum alloys. Exploratory analysis of five types of aluminum alloys by PCA was performed to achieve better segregation. The identification accuracy of the support‐vector machine (SVM) and LSSVM for aluminum alloy were 98.33% and 100%, respectively. The higher identification success rate was obtained using the LSSVM algorithm. Therefore, the LIBS technique combined with the PCA and LSSVM algorithms represents an efficient approach to identifying aluminum alloys.
Technical Note: An alternative approach to verify 6FFF beam dosimetry for Ethos and MR Linac without using a 3D water tank
Authors: Hao Yao , Cai Bin , Green Olga , Knutson Nels , Yaddanapudi Sridhar , Zhao Tianyu , Rodriguez Vivian , Schmidt Matthew , Mutic Sasa , Sun Baozhou
Published: February 2021

Purpose

The current approach to Linac beam dosimetry verification is typically performed utilizing a three‐dimensional (3D) water tank system. The 3D beam scanning process is cumbersome, labor intensive, error‐prone, and costly. This is especially challenging for the new Ethos system and MR Linacs with a ring gantry. This work proposes an alternative approach to verify 6FFF beam dosimetry for Ethos, ViewRay MRIdian® Linac, and other Linacs with 6FFF beam quality using two‐dimensional (2D) ion chamber arrays.

Methods

Percentage depth dose (PDD) and profiles of an Ethos, an MRIdian® Linac, and several Linacs with 6FFF beams were measured at the nominal beam current. The beam energy was detuned by changing the bending magnet current on one TrueBeam. PDDs and profiles were measured for detuned beam energies. The peak shape of the 6FFF profile was defined by a “slope” parameter and unflatness. Correlations between peak slope and unflatness metrics vs PDDs were used to evaluate the sensitivity of beam energy to beam profile changes at different field sizes and depths.

Results

Strong correlations were found between peak slope and PDDs for all Linacs with 6FFF beam. The R‐squared values in the linear regression fitting between PDD and peak slope and unflatness were 0.99 and 0.84, respectively. Both profile slope and unflatness were proportional to PDD at the 10 cm depth and the peak slope was 4.3 times more sensitive than PDD. We have identified that measurements with a shallow depth are preferred to quantify the beam energy consistency.

Conclusions

Our work shows the feasibility of verifying 6FFF beam quality of Ethos, MR Linac, and other Linacs by defining a profile slope measured from 2D ionization chambers array devices. This new approach provides a simplified method for performing a routine beam quality check without using a 3D water tank system while maximizing cost effectiveness and efficiency.
Self‐sealing thermoplastic fluoroelastomer enables rapid fabrication of modular microreactors
Authors: McMillan Alexander H. , Mora‐Macías Juan , Teyssandier Joan , Thür Raymond , Roy Emmanuel , Ochoa Ignacio , De Feyter Steven , Vankelecom Ivo F. J. , Roeffaers Maarten B. J. , Lesher‐Pérez Sasha Cai
Published: February 2021

A novel fluorinated soft thermoplastic elastomer (sTPE) for microfluidics is presented. It allows the rapid fabrication of microfluidic devices through a 30‐second hot embossing cycle at 220°C followed by self‐sealing through simple conformal contact at room temperature, or with baking. The material shows high chemical resistance, particularly in comparison to polydimethylsiloxane (PDMS), to many common organic solvents and can be rapidly micropatterned with high fidelity using a variety of microfluidic master molds thanks to its low mechanical stiffness. Self‐sealing of the material is reversible and withstands pressures of up to 2.8 bar with room temperature sealing and four bar with baking at 185°C for 2 hours. The elastomeric, transparent sTPE exhibits material characteristics that make it suited for use as a microreactor, such as low absorption, surface roughness and oxygen permeability, while also allowing a facile and scalable fabrication process. Modular microfluidic devices, leveraging the fast and reversible room temperature self‐sealing, are demonstrated for the generation of water droplets in a toluene continuous phase using T‐junctions of variable size. The sTPE offers an alternative to common microfluidic materials, overcoming some of their key drawbacks, and giving scope for low‐cost and high‐throughput devices for flow chemistry applications.
Optoelectronic properties improvement of double perovskites Cs2Sn(Pb)I6 by the hydrothermal method
Authors: Wu Junsheng , Zhao Zhuo , Li Tong , Zhang Kaice , Fang Fang , Zhou Yanwen
Published: February 2021

Herein, we report on the synthesis of perovskite Cs2Sn(Pb)I6 powder via a modified hydrothermal method, in which Pb2+ ions are introduced to Cs2SnI6 to optimize the semiconductor properties of double perovskite. Results indicate that the introduction of 2 at% Pb2+ into the Cs2SnI6 not only facilitates fine thermal stability, smoother surface with small grain size, expanding the scope of absorption. Thence the photovoltaic properties of Cs2SnI6 are improved where obtained a higher photocurrent density (∼ 70 µA cm−2). Combined with changes in photoelectric properties, perhaps a small amount of Pb doping plays a role in reducing the formation energy and surface energy of the compounds. On the contrary, excessive Pb doping destroys the synthesis of Cs2SnI6 and reduces the purity of the compound; thus, affecting its application. This study provides useful insights into the development of double perovskites with high stability and efficiency.
In situ investigation of formation kinetics of microporous structure in PVDF thin films prepared via thermally‐induced phase separation (TIPS): Effects of film thickness and polymer concentration
Authors: Yang Bin , Yu Yang‐nan , Pan Yang , Wang Shu‐qing , Xu Xiang , Wang Ying‐ying , Qian Jia‐sheng , Xia Ru , Zhang Peng , Shi You , Tu You‐lei
Published: February 2021

In this research, series of PVDF microporous films with various polymer concentrations and thickness were prepared through thermally‐induced phase separation in air condition with diphenyl carbonate as the diluent. Effects of polymer concentration and film thickness on the formation kinetics of microporous structure of PVDF thin films were in situ investigated via TII technique. The instantaneous heat conduction inside the films during film formation was also evaluated. Two types of parameter models were adopted in order to disclose the time and location dependence of TIPS film solidification kinetics, respectively. Hierarchical microstructures, crystallization behavior and thermal properties of the TIPS films were also characterized by SEM, DSC, and TGA, respectively. The current study could supply an insight into the fabrication of PVDF microporous films with target microstructure and desirable performance.
Effect of offset‐frequency step size and interpolation methods on chemical exchange saturation transfer MRI computation in human brain
Authors: Debnath Ayan , Gupta Rakesh Kumar , Reddy Ravinder , Singh Anup
Published: February 2021

Chemical exchange saturation transfer (CEST) MRI is a non‐invasive molecular imaging technique with potential applications in pre‐clinical and clinical studies. Applications of amide proton transfer‐weighted (APT‐w), glutamate‐weighted (Glu‐w) and creatine‐weighted (Cr‐w) CEST, among others, have been reported. In general, CEST data are acquired at multiple offset‐frequencies. In reported studies, different offset‐frequency step sizes and interpolation methods have been used during B0 inhomogeneity correction of data. The objective of the current study was to evaluate the effects of different step sizes and interpolation methods on CEST value computation. In the current study, simulation (Glu‐w, Cr‐w and APT‐w) and experimental data from the brain were used. Experimental CEST data (Glu‐w) were acquired from human volunteers at 7 T and brain tumor patients (APT‐w) at 3 T. During B0 inhomogeneity correction, different interpolation methods (polynomial [degree‐1, 2 and 3], cubic‐Hermite, cubic‐spline and smoothing‐spline) were compared. CEST values were computed using asymmetry analysis. The effects of different step sizes and interpolation methods were evaluated using coefficient of variation (CV), normalized mean square error (nMSE) and coefficient of correlation parameters. Additionally, an optimum interpolation method for APT‐w values was selected based upon fitting accuracy, T‐test, receiver operating characteristic analysis, and its diagnostic performance in differentiating low‐grade and high‐grade tumors. CV and nMSE increase with an increase in step size irrespective of the interpolation method (except for cubic‐Hermite and cubic‐spline). The nMSE of Cr‐w and Glu‐w CEST values were least for polynomial (degree‐2 and 3). The quality of Glu‐w CEST maps became coarse with the increase in step size. There was a significant difference (P < .05) between low‐grade and high‐grade tumors using polynomial interpolation (degree‐1, 2 and 3); however, linear interpolation outperforms other methods for APT‐w data, providing the highest sensitivity and specificity. In conclusion, depending upon the saturation parameters and field strength, optimization of step size and interpolation should be carried out for different CEST metabolites/molecules. Glu‐w, Cr‐w and APT‐w CEST data should be acquired with a step size of between 0.2 and 0.3 ppm. For B0 inhomogeneity correction, polynomial (degree‐2) should be used for Glu‐w and Cr‐w CEST data at 7 T and linear interpolation should be used for APT‐w data at 3 T for a limited frequency range.
Circulating Tumor DNA-Based Testing and Actionable Findings in Patients with Advanced and Metastatic Pancreatic Adenocarcinoma
Authors: Botrus Gehan , Kosirorek Heidi , Sonbol Mohamad Bassam , Kusne Yael , Uson Pedro Luiz Serrano , Borad Mitesh J. , Ahn Daniel H. , Kasi Pashtoon M. , Drusbosky Leylah M. , Dada Hiba , Surapaneni Phani Keerthi , Starr Jason , Ritter Ashton , McMillan Jessica , Wylie Natasha , Mody Kabir , Bekaii-Saab Tanios S.
Published: February 2021

Purpose

Recent advances in molecular diagnostic technologies allow for the evaluation of solid tumor malignancies through noninvasive blood sampling, including circulating tumor DNA profiling (ctDNA). Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, often because of late presentation of disease. Diagnosis is often made using endoscopic ultrasound or endoscopic retrograde cholangiopancreatography, which often does not yield enough tissue for next-generation sequencing. With this study, we sought to characterize the ctDNA genomic alteration landscape in patients with advanced PDAC with a focus on actionable findings.

Materials and Methods

From December 2014 through October 2019, 357 samples collected from 282 patients with PDAC at Mayo Clinic underwent ctDNA testing using a clinically available assay. The majority of samples were tested using the 73-gene panel which includes somatic genomic targets, including complete or critical exon coverage in 30 and 40 genes, respectively, and in some, amplifications, fusions, and indels. Clinical data and outcome variables were available for 165 patients; with 104 patients at initial presentation.

Results

All patients included in this study had locally advanced or metastatic PDAC. Samples having at least one alteration, when variants of unknown significance (VUS) were excluded, numbered 266 (75%). After excluding VUS, therapeutically relevant alterations were observed in 170 (48%) of the total 357 cohort, including KRAS (G12C), EGFR, ATM, MYC, BRCA, PIK3CA, and BRAF mutations. KRAS, SMAD, CCND2, or TP53 alterations were seen in higher frequency in patients with advanced disease.

Conclusion

Our study is the largest cohort to date that demonstrates the feasibility of ctDNA testing in PDAC. We provide a benchmark landscape upon which the field can continue to grow. Future applications may include use of ctDNA to guide treatment and serial monitoring of ctDNA during disease course to identify novel therapeutic targets for improved prognosis.

Implications for Practice

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis often due to late presentation of disease. Biopsy tissue sampling is invasive and samples are often inadequate, requiring repeated invasive procedures and delays in treatment. Noninvasive methods to identify PDAC early in its course may improve prognosis in PDAC. Using ctDNA, targetable genes can be identified and used for treatment.
Functional modification of silicone rubber through nano‐hydroxylapatite embedding
Authors: Bindu Mavila , Ananthapadmanabhan Unnikrishnan
Published: February 2021

Silicone rubber (SR) has extensively been used for different industrial and biomedical applications, in view of its good elasticity, chemical inertness, and biocompatibility. However, cure inhibition features, poor mechanical properties, and hydrophobicity, often, limit the possible expansion of its spectrum of applications. The present work has been designed to address these issues by embedding a potential biocompatible filler, nano‐hydroxylapatite (n‐HA), within the SR matrix, through compression molding. The n‐HA particles were initially synthesized by a wet chemical method, and were subsequently introduced into SR quantitatively. The rheological features, compressive properties, simulated body fluid (SBF) uptake, bovine serum albumin (BSA) adsorption, blood compatibility, and cytocompatibility of n‐HA modified SR systems have been investigated. The change in rheological characteristics after n‐HA embedding within SR clearly indicated the favorable interactions between them, and a compatible functional existence under external stresses. The compressive strength, which is critical for the different applications of SR, has been found to be increased with an increase in n‐HA loading. In‐vitro mineralization studies using SBF showed the formation of apatite crystals on the surface of SR/n‐HA system indicating its biocompatibility. This has been confirmed by SEM and FTIR examinations. It has further been observed that the addition of n‐HA particles into SR matrix enhances the protein adsorption characteristics. The n‐HA embedded system exhibited excellent blood compatibility, which has been complemented through hemolysis (%) studies and thrombogenicity assay. The results indicate that the strategy of n‐HA embedding would do significant value addition to SR, and widen its scope in the industrial and biomedical sectors.
Mathematical and finite element analysis estimations of the reinforcement effect on Young's modulus of polymer membrane/montmorillonite clay nanocomposites
Authors: Santiago Arlette A. , Vargas Joel , Pérez Luis , Corona‐García Carlos , Alfonso Ismeli
Published: February 2021

This work attempts to estimate the effect of the reinforcement percentage on Young's modulus for membranes of polymer‐clay nanocomposites (PCNs). Models tried to simulate different contents of the reinforcement for experimentally obtained PCNs with nanometric montmorillonite clays (MMT) incorporated into a polynorbornene dicarboximide matrix. The analyses were carried out modeling through discrete element method (DEM) and finite element analysis (FEA) volume fractions from 0.01 to 0.025 of elliptical MMT nano‐platelets with aspect ratios = 0.2 (1000 × 500 nm) and thicknesses of 1 nm. These models were generated using as starting point the morphology and distribution of the reinforcements observed in scanning electron microscopy for experimental PCNs. Estimations were compared to predictions obtained by Rule of Mixtures and other mathematical models. Results showed that the elastic modulus of the nanocomposites significantly rises as MMT volume fraction increases. Besides, the use of DEM‐FEA generated the predictions closest to the experimental values, with relative errors lower than 10%. For the other models, the errors were significantly high, even reaching 100%. This shows the importance of DEM‐FEA to obtain a more accurate model of a real composite and a better estimation of its mechanical behavior.
Development and validation of the reading motivation questionnaire in an English as a foreign language context
Authors: Wang Wenjiao , Gan Zhengdong
Published: February 2021

This paper presents the development and validation of the reading motivation questionnaire in an English as a foreign language context (RMQ‐EFL) with Chinese secondary students. Data were collected from a sample of 293 secondary students in grades 10–11. Exploratory and confirmatory factor analyses resulted in determination of five factors (i.e.,reading efficacy, reading enjoyment, recognition, involvement, andcompliance) with a strong psychometric basis. The significant correlations between these five RMQ‐EFL factors and students' learning strategies in reading and between the five RMQ‐EFL factors and students' English learning achievements further confirmed the concurrent and predictive validity of the RMQ‐EFL. In addition, this study found that there were no significant differences in students' EFL reading motivation across gender and grade levels. The RMQ‐EFL can be used both as an evaluation tool for teachers to assess students' EFL reading motivation, and as a research tool for researchers to explore the relationships between students' English reading motivation and their English reading behavior and performance or to assess the effectiveness of targeted reading motivation interventions.
High‐Precision Density Measurements of Energetic Materials for Quality Assessment
Authors: Herrmannsdörfer Dirk , Klapötke Thomas M.
Published: February 2021

Even though helium pycnometry is considered a very precise method of density determination, its use to analyse factors influencing crystal quality (e. g. solvent inclusions, amorphous states, crystal defects…) is limited due to the unknown inherent accuracy of the method. Previous studies have attempted to identify the best possible accuracy of helium pycnometry. However, no robust method has been proposed to validate even the precision obtained. This means that the often occurring, seemingly random density deviations have never been satisfactorily explained. In this study the influencing factors on density measurements of the CL‐20/HMX cocrystal and phase stabilised ammonium nitrate carried out with an AccuPyc 1340 TEC were quantified and a robust method of data analysis was developed to judge with certainty the quality and significance of the data obtained. This study shows that statistical tests such as the t‐test and ANOVA cannot be utilised to differentiate between samples or repeat measurements, even though the density data points exhibit a normal distribution. By utilising confidence intervals and quantifying the three major sources of error (sampling error, change in barometric pressure during the measurement, and weight in error), a repeatability of 0.015 % was achieved and a method was developed that enables differentiation between samples with a certainty as good as 0.05 %.
Integration of wavelet decomposition and artificial neural network for failure prognosis of reciprocating compressors
Authors: Lu Yen‐Ju , Wang Chen‐Hua
Published: February 2021

Compressors in petrochemical plants are often crucial to process operations, and when a failure occurs, the outcome can be catastrophic. Many researches have been attempting to detect failure modes as early as possible to plan upfront repair and conceivably reduce maintenance time. A reciprocating compressor was selected as the target of this study, and a few years of historical records of maintenance parameters and maintenance work orders were gathered for analysis. The time history was divided into 13 events, and each event started with a normal operation and ended with a repair work order. Time‐domain features and wavelet decomposition features of the parameters were extracted, and the patterns stored within each event were identified using the artificial neural network and support vector machine. Moreover, a set of reasoning algorithms were developed to detect anomalies, and responsible failure modes were identified. For a specific type of compressor, the vibration signal was found to be related to most of the anomalies and thus used for evaluation. Results showed a >90% detection rate for failure mode diagnosis based on historical test data.
Sub‐Microsecond Polarization Switching in (Al,Sc)N Ferroelectric Capacitors Grown on Complementary Metal–Oxide–Semiconductor‐Compatible Aluminum Electrodes
Authors: Wang Dixiong , Musavigharavi Pariasadat , Zheng Jeffrey , Esteves Giovanni , Liu Xiwen , Fiagbenu Merrilyn Mercy Adzo , Stach Eric A. , Jariwala Deep , Olsson Roy H.
Published: February 2021

The frequency‐dependent ferroelectric properties of 45 nm (Al,Sc)N films sputter deposited on complementary metal–oxide–semiconductor (CMOS)‐compatible Al metal electrodes are measured and compared. Low in‐plane compressive stress (−10 ± 20 MPa) is observed in (Al,Sc)N thin films deposited on Al electrodes. The (Al,Sc)N films exhibit an imprint in the measured coercive fields (Ec) of −4.3/+5.3 MV cm−1 at 10 kHz. Utilizing positive‐up negative‐down (PUND) measurements, ferroelectric switching is observed within ≈200 ns of an applied voltage pulse, which demonstrates the ability of ferroelectric (Al,Sc)N to achieve the fast read/write speeds desired in memory devices.
Optimal designs for dual response systems for the normal and binomial case
Authors: Burke Sarah E. , Montgomery Douglas C. , Anderson‐Cook Christine M. , Silvestrini Rachel T. , Borror Connie M.
Published: February 2021

Most research in design of experiments focuses on appropriate designs for a system with just one type of response, rather than multiple responses. In a decision‐making process, relying on only one objective can lead to oversimplified, suboptimal choices that ignore important considerations. Consequently, the problem of constructing a design for an experiment when multiple types of responses are of interest often does not have a single definitive answer, particularly when the response variables have different distributions. Each of these response distributions imposes different requirements on the experimental design. Computer‐generated optimal designs are popular design choices for less standard scenarios where classical designs are not ideal. This work presents a new approach to experimental designs for dual‐response systems. The normal and binomial distributions are considered as potential responses. Using the D‐criterion for the linear model and the Bayesian D‐criterion for the logistic regression model, a weighted criterion is implemented in a coordinate‐exchange algorithm. Designs are evaluated and compared across different weights. The sensitivity of the designs to the priors supplied for the Bayesian D‐criterion is also explored.
Evaluation of a quick one‐step sample preparation method for the determination of the isotopic fingerprint of rapeseed (Brassica napus): Investigation of the influence of the use of 2,2‐dimethoxypropane on compound‐specific stable carbon and hydrogen isotope analyses by gas chromatography combustion/pyrolysis isotope ratio mass spectrometry
Authors: Xia Lili , Sakaguchi‐Söder Kaori , Stanojkovski Daniel , Schebek Liselotte
Published: February 2021

Rationale

Gas chromatographic analyses for vegetable oils require transesterification, which generally involves multiple steps, mainly to generate fatty acid methyl esters (FAMEs). A quick method based on acid‐catalyzed transesterification using 2,2‐dimethoxypropane (DMP) enables the conversion in one step, in a single reactor. For compound‐specific stable carbon and hydrogen isotope analyses (C‐ and H‐CSIA) of individual fatty acids (FAs) in oil, the verification of this one‐step method has not yet been reported.

Methods

In this study, we evaluated the feasibility of the one‐step method for C‐ and H‐CSIA of individual FAMEs in rapeseed samples. The focus was on the investigation of the influence of methanol, which was produced from the reactions of DMP with glycerol and water during transesterification, on the accuracy of isotope composition of FAMEs, consequently of the FAs. The reproducibility of the one‐step method was assessed by the measurement of the FAMEs from rapeseed and rapeseed oil. For the C‐ and H‐CSIA of individual FAMEs, a gas chromatography combustion/pyrolysis isotope ratio mass spectrometry system was used.

Results

Our results showed that no significant differences arise in the carbon and hydrogen isotope compositions of the selected main FAMEs produced with and without DMP except for the H‐CSIA value of C18:3. The reproducibility of the one‐step method for rapeseed was in the range of ±0.1 mUr to ± 0.3 mUr for C‐CSIA and ±1 mUr to ±3 mUr for H‐CSIA of the main FAMEs.

Conclusions

DMP improves the transesterification efficiency without influencing the accuracy of the C‐ and H‐CSIA of FAMEs. The performance of the one‐step method for rapeseed samples for the determination of C‐ and H‐CSIA values of FAMEs is satisfactory. Thus, the applicability of the one‐step method for isotopic fingerprint analyses of FAs in oilseeds is reported for the first time.