bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal‐Assisted Efficient Nanotubular Electrocatalyst of MoS2 for Hydrogen Production
Authors: Anh Ho Thi , Kim Eunsoo , Yang Hyunwoo , Joe Jemee , Hyeok Park Jong , Shin Hyunjung
Published: April 2021

Inspired by the catalytic activity along the edge sites of layered‐structured MoS2 for the hydrogen evolution reaction (HER), maximizing the specific active edge sites per unit geometric area via material architectural design is the most common strategy for enhancing HER performance. Here, we report a convenient growth approach using atomic layer deposition (ALD) to obtain novel nanostructures of MoS2 nanotube arrays with a high number of exposed active edge sites. MoS2 NTs were spontaneously immobilized in an ordered arrangement of anodic aluminum oxide (AAO) template with a well‐defined size and shape. Ordered MoS2 NTs array were fabricated with highly conductive, large electrochemical active area as an efficient HER catalyst. Strikingly, by engineering the contact metal serving as the current collector, the contact properties were revealed to be important factors for the electrocatalytic performance of the metal‐assisted MoS2 electrodes. Our material system shows a significantly low overpotential of 260 mV at 10 mA/cm2 and a Tafel slope of 55 mV/dec, while it remains stable during long‐term operation in strong acidic media.
Probing the Catalytically Active Species in POM‐Catalysed DNA‐Model Hydrolysis**
Authors: Martins Frederico F. , Sánchez‐González Ángel , Lanuza Jose , Miras Haralampos N. , Lopez Xabier , Bandeira Nuno A. , Gil Adrià
Published: April 2021

Phosphoester hydrolysis is an important chemical step in DNA repair. One archetypal molecular model of phosphoesters is para‐nitrophenylphosphate (pNPP). It has been shown previously that the presence of molecular metal oxide [Mo7O24]6− may catalyse the hydrolysis of pNPP through the partial decomposition of polyoxomolybdate framework resulting in a [(PO4)2Mo5O15]6− product. Real‐time monitoring of the catalytic system using electrospray ionisation mass spectrometry (ESI‐MS) provided a glance into the species present in the reaction mixture and identification of potential catalytic candidates. Following up on the obtained spectrometric data, Density Functional Theory (DFT) calculations were carried out to characterise the hypothetical intermediate [Mo5O15(pNPP)2(H2O)6]6− that would be required to form under the hypothesised transformation. Surprisingly, our results point to the dimeric [Mo2O8]4− anion resulting from the decomposition of [Mo7O24]6− as the active catalytic species involved in the hydrolysis of pNPP rather than the originally assumed {Mo5O15} species. A similar study was carried out involving the same species but substituting Mo by W. The mechanism involving W species showed a higher barrier and less stable products in agreement with the non‐catalytic effect found in experimental results.
CoS2/N‐Doped Hollow Spheres as an Anode Material for High‐Performance Sodium‐Ion Batteries
Authors: Liu Jianyu , Wu Jixian , Fan Siwei , Li Guangda
Published: April 2021

In this work, we first synthesized polyacrylic acid (PAA) spheres and then used PAA as a template to load Co(OH)2 particles onto its surface. The product of CoS2 nanoparticles dispersed in N‐doped hollow spheres (N‐HCS) was prepared through sulfurization treatment (CoS2/S@N‐HCS). During the sulfuration process, sulfur penetrates into the PAA, embedding into the graphite layer along with the carbonization process. It was found that during the charging and discharging process, the sulfur in the carbon layer will gradually dissolve out, thereby forming new ion diffusion channels in the carbon spheres and exposing more CoS2 active sites. The CoS2/S@N‐HCS composite exhibits a specific capacity of 729.6 mAh g−1 after 500 cycles at a current density of 1 A g−1. The sodium‐storage mechanism and reaction kinetics of the materials were further measured by in‐situ electrochemical impedance spectroscopy, ex‐situ X‐ray diffraction, capacitance performance evaluation, and galvanostatic intermittent titration technique. The excellent cycling performance and rate capability demonstrated that the CoS2/S@N‐HCS is a potential and prospective anode material for sodium‐ion batteries.
Oxochloroselenate(IV) with Incorporated {Cl2}: The Case of Strong Cl⋅⋅⋅Cl Halogen Bonding
Authors: Usoltsev Andrey N. , Korobeynikov Nikita A. , Kolesov Boris A. , Novikov Alexander S. , Abramov Pavel A. , Sokolov Maxim N. , Adonin Sergey A.
Published: April 2021

Reaction of SeO2, tetramethylammonium (TMA) chloride, aqueous HCl and Cl2 yields oxochloroselenate with incorporated Cl2 units, TMA3{[Se2O2Cl7](Cl2)}. The main feature of this compound is the strong (up to 3.5 kcal mol−1, according to DFT calculations) Cl⋅⋅⋅Cl bonding, which is also detected by Raman spectroscopy.
Relay‐Heck Cross‐Coupling Between Alkenyl Halides and Unsaturated Alcohols in the Synthesis of Open‐Chain Analogues of Musk Odorant Vulcanolide
Authors: Lenormand Anthony , Reyes Méndez Lucía , Coulomb Julien
Published: April 2021

Unactivated alkenyl iodides and bromides underwent an unprecedented palladium‐catalyzed relay‐Heck cross‐coupling with a whole range of alkenols of different chain lengths linking the alkene and the alcohol, affording unsaturated aldehydes and ketones in moderate to good yields. In contrast, alkenyl triflates were not suitable partners for this reaction. This method allowed the preparation of open‐chain analogues of the musk odorant Vulcanolide, several of which retained key olfactory properties of the parent molecule.
Coordination‐Driven Selective Formation of D2 Symmetric Octanuclear Organometallic Cages
Authors: Zhang Long , Lin Yue‐Jian , Li Zhen‐Hua , Fraser Stoddart J. , Jin Guo‐Xin
Published: April 2021

The coordination‐driven self‐assembly of organometallic half‐sandwich iridium(III)‐ and rhodium(III)‐based building blocks with asymmetric ambidentate pyridyl‐carboxylate ligands is described. Despite the potential for obtaining a statistical mixture of multiple products, D2 symmetric octanuclear cages were formed selectively by taking advantage of the electronic effects emanating from the two types of chelating sites – (O,O’) and (N,N’) – on the tetranuclear building blocks. The metal sources and the lengths of bridging ligands influence the selectivity of the self‐assembly. Experimental observations, supported by computational studies, suggest that the D2 symmetric cages are the thermodynamically favored products. Overall, the results underline the importance of electronic effects on the selectivity of coordination‐driven self‐assembly, and demonstrate that asymmetric ambidentate ligands can be used to control the design of discrete supramolecular coordination complexes.
CFD‐DEM analysis of the spouted fluidized bed with non‐spherical particles
Authors: Esgandari Behrad , Golshan Shahab , Zarghami Reza , Sotudeh‐Gharebagh Rahmat , Chaouki Jamal
Published: April 2021

Hydrodynamics of spouted fluidized beds of spherical and elongated sphero‐cylindrical particles with an aspect ratio (AR) of 4 were studied by the CFD‐DEM technique. The multi‐sphere method was adopted to present the sphero‐cylindrical particles. Simulations were validated with the experimental data for both particle types. Bubble equivalent diameter, bubble shape factor, and leakage fraction were obtained in the simulations. Time‐averaged particle velocity and porosity profiles, solids circulation rate, particle exchange distribution at the spout‐annulus interface, were investigated in the beds filled with spherical and sphero‐cylindrical particles at gas mass flow rates of 0.005, 0.007, and 0.009 kg/s. The equivalent bubble diameter was found to be lower for spherical particles compared to sphero‐cylindrical particles. The leakage fraction of the bubble was lower for sphero‐cylindrical particles. Solid circulation rate and spout diameter were larger for the bed of spherical particles. A higher probability of particles transition into the spout was observed for spherical particles. Investigating the orientation showed that sphero‐cylindrical particles tend to orient almost vertically against the gas flow in the spout region, which lowers the exerted drag force, whereas the particles align nearly horizontally in the annulus region. The results revealed that the CFD‐DEM approach is a promising method for investigating the fluid and both spherical and non‐spherical particle behaviours in spouted fluidized beds.
Chemical Reactions Trigger Peptide Self‐Assembly in vivo for Tumor Therapy
Authors: Zeng Xiang‐Zhong , An Hong‐Wei , Wang Hao
Published: April 2021

Self‐assembly peptide materials have promoted the development of science research including life science, optics, medicine, and catalysis over the past two decades. Especially in tumor treatment, peptide self‐assembly strategies have exhibited promising potential by their high degree of biocompatibility, construction modularization, and diversity in structure controllability. Driven by physical and chemical triggers, peptides can self‐assemble in vivo to form fibers, spheres, hydrogels, or ribbons to achieve predeterminate biological functions. Peptide self‐assembly triggered by chemical reactions provides superior specificity and intelligent responsiveness to produce assembly‐induced biological effects in target regions. Herein, from the perspective of triggers of peptide assembly, we briefly review the applications of in vivo peptide self‐assembly strategies for tumor treatment, including tumor‐pathology‐factor‐induced chemical reactions and bio‐orthogonal reactions
Cause of death during prostate cancer survivorship: A contemporary, US population–based analysis
Authors: Weiner Adam B. , Li Eric V. , Desai Anuj S. , Press David J. , Schaeffer Edward M.
Published: April 2021

BACKGROUND

More than 3.6 million men in the United States harbor a diagnosis of prostate cancer (PCa). The authors sought to provide in‐depth analyses of the causes of death for contemporary survivors.

METHODS

The authors performed a population‐based cohort study in the United States (2000‐2016) to assess causes of death for men diagnosed with PCa stratified by demographics and tumor stage. Using general population data, they calculated standardized mortality ratios (SMRs) as observed‐to‐expected death ratios.

RESULTS

In total, 752,092 men with PCa, including 200,302 who died (27%), were assessed. A total of 29,048 men with local/regional disease (17%) died of PCa, whereas more than 4‐fold men died of other causes (n = 143,719 [83%]). SMRs for death from noncancer causes (0.77; 95% confidence interval [CI], 0.77‐0.78) suggested that these men were less likely than the general population to die of most other causes. The most common noncancer cause of death was cardiac‐related (23%; SMR, 0.76; 95% CI, 0.75‐0.77). Among men with distant PCa, 90% of deaths occurred within 5 years of diagnosis. Although deaths due to PCa composed the majority of deaths (74%), SMRs suggested that men with distant PCa were at heightened risk for death from most other noncancer causes (1.50; 95% CI, 1.46‐1.54) and, in particular, for cardiac‐related death (SMR, 1.48; 95% CI, 1.41‐1.54) and suicide (SMR, 2.32; 95% CI, 1.78‐2.96). Further analyses demonstrated that causes of death varied by patient demographics.

CONCLUSIONS

Causes of death during PCa survivorship vary by patient and tumor characteristics. These data provide valuable information regarding health care prioritization during PCa survivorship.

LAY SUMMARY

Men with early‐stage prostate cancer are 4‐fold more likely to die of other causes, whereas those with advanced prostate cancer are at increased risk for several causes not related to prostate cancer in comparison with the general population.

These findings can help guide physicians taking care of men with a diagnosis of prostate cancer.
Impact of fertility concerns on endocrine therapy decisions in young breast cancer survivors
Authors: Sella Tal , Poorvu Philip D. , Ruddy Kathryn J. , Gelber Shari I. , Tamimi Rulla M. , Peppercorn Jeffrey M. , Schapira Lidia , Borges Virginia F. , Come Steven E. , Partridge Ann H. , Rosenberg Shoshana M.
Published: April 2021

Background

The diagnosis and treatment of breast cancer can have profound effects on a young woman's family planning and fertility, particularly among women with hormone receptor–positive breast cancer.

Methods

The Young Women's Breast Cancer Study was a multicenter cohort of women aged 40 years or younger and newly diagnosed with breast cancer from 2006 to 2016. Surveys included assessments of fertility concerns, endocrine therapy (ET) preferences, and use. Characteristics were compared between women who reported that fertility concerns affected ET decisions and those who did not. Logistic regression was used to identify factors associated with having an ET decision affected by fertility concerns.

Results

Of 643 eligible women with hormone receptor–positive, stage I to III breast cancer, one‐third (213 of 643) indicated that fertility concerns affected ET decisions. In a multivariable analysis, only parity at diagnosis was significantly associated with fertility concerns affecting ET decisions (odds ratio for nulliparous vs ≥2 children, 6.96; 95% confidence interval, 4.09‐11.83; odds ratio for 1 vs ≥2 children, 5.30; 95% confidence interval, 3.03‐9.87). Noninitiation/nonpersistence was higher among women with fertility concerns versus those without fertility concerns (40% vs 20%; P < .0001). Among women with fertility‐related ET concerns, 7% (15 of 213) did not initiate ET, and 33% (70 of 213) were nonpersistent over 5 years of follow‐up. Of these women, 66% (56 of 85) reported 1 or more pregnancies or pregnancy attempts; 27% (15 of 56) had resumed ET at the last available follow‐up through 5 years.

Conclusions

Concern about fertility is a contributor to adjuvant ET decisions among a substantial proportion of young breast cancer survivors. Ensuring family planning is addressed in the setting of ET recommendations should be a priority throughout the cancer care continuum.
Evaluation of the diagnostic accuracy of bronchial brushing cytology in lung cancer: A meta‐analysis
Authors: Chen Cheng‐Chieh , Bai Chyi‐Huey , Lee Kang‐Yun , Chou Yu‐Ting , Pan Shien‐Tung , Wang Yuan‐Hung
Published: April 2021

Background

Flexible bronchoscopy is commonly used to examine patients suspected to have lung cancer. Bronchial brushing is one of the cytological technologies for lung specimens obtained through a bronchoscope. However, the accuracy of bronchial brushing cytology (BBC) for lung cancer diagnosis is still inconclusive. The aim of this study was to evaluate the diagnostic accuracy of BBC.

Methods

A literature search was conducted with PubMed, Embase, the Cochrane Library, Web of Science, Biomed Central, Clinical Key, and ClinicalTrials.gov. Studies that assessed the efficacy of BBC in detecting lung cancer were included. Articles that estimated the accuracy on a per‐patient basis were included. Review articles, case reports, and research that provided insufficient data to construct a 2 × 2 table were excluded. Both prospective trials and retrospective studies were included. English language studies were reviewed. Data synthesis was performed with a random‐effects model.

Results

Seventeen studies with 2538 patients were included in the study. The meta‐analysis for BBC generated a pooled sensitivity of 0.67 (95% confidence interval [CI], 0.65‐0.70) and a pooled specificity of 0.91 (95% CI, 0.89‐0.93). The pooled diagnostic odds ratio for BBC was 24.55 (95% CI, 12.39‐48.66). The subgroup analysis for studies using liquid‐based cytology (LBC) generated a pooled sensitivity of 0.68 and a pooled specificity of 0.92. The pooled diagnostic odds ratio of studies using LBC was 114.18.

Conclusions

These findings indicate that BBC is a discriminative diagnostic approach with moderate sensitivity and high specificity for diagnosing peripheral pulmonary lesions. BBC using LBC has higher diagnostic performance.
Pharmacokinetics of Ginsenoside Compound K From a Compound K Fermentation Product, CK‐30, and From Red Ginseng Extract in Healthy Korean Subjects
Authors: Ban Mu Seong , Kim Yun , Lee Sunyoung , Han ByongYeul , Yu Kyung‐Sang , Jang In‐Jin , Chung Hong Keun , Lee SeungHwan
Published: April 2021

Natural protopanaxadiol ginsenosides exhibit low absorption in the human intestine. However, ginsenoside compound K (CK) with 1 conjugated glucose molecule exhibits favorable absorption. The purpose of this study was to compare the pharmacokinetics of ginsenoside CK from a CK fermentation product, CK‐30, and from a red ginseng extract. A randomized, open‐label, 2‐treatment, 2×2 crossover study was conducted. The volunteers were randomly divided into 2 groups. One group received CK‐30, and the other group received 2.94 g of a red ginseng extract. After a 7‐day washout period, the subjects received an alternative treatment for a single dose. The pharmacokinetic parameters, including the maximum plasma concentration (Cmax) and area under the plasma concentration–time curve from time 0 to time of last measurable concentration, were calculated. The median time to reach Cmax of ginsenoside CK after administration of CK‐30 was 3.0 hours, whereas the corresponding value of the red ginseng extract was 10.0 hours. Compared with the red ginseng extract, CK‐30 resulted in a higher systemic exposure to ginsenoside CK, with a 118.3‐fold increase in Cmax and a 135.1‐fold increase in area under the plasma concentration–time curve from time 0 to time of last measurable concentration. The systemic exposure to ginsenoside CK was significantly higher after administration of CK‐30 than red ginseng extract.
Multi‐angle head pose classification with masks based on color texture analysis and stack generalization
Authors: Li Shuang , Dong Xiaoli , Shi Yuan , Lu Baoli , Sun Linjun , Li Wenfa
Published: April 2021

Head pose classification is an important part of the preprocessing process of face recognition, which can independently solve application problems related to multi‐angle. But, due to the impact of the COVID‐19 coronavirus pandemic, more and more people wear masks to protect themselves, which covering most areas of the face. This greatly affects the performance of head pose classification. Therefore, this article proposes a method to classify the head pose with wearing a mask. This method focuses on the information that is helpful for head pose classification. First, the H‐channel image of the HSV color space is extracted through the conversion of the color space. Then use the line portrait to extract the contour lines of the face, and train the convolutional neural networks to extract features in combination with the grayscale image. Finally, stacked generalization technology is used to fuse the output of the three classifiers to obtain the final classification result. The results on the MAFA dataset show that compared with the current advanced algorithm, the accuracy of our method is 94.14% on the front, 86.58% on the more side, and 90.93% on the side, which has better performance.
The associations of obsessive–compulsive symptom dimensions and general severity with suicidal ideation in patients with obsessive–compulsive disorder: The role of specific stress responses to COVID‐19
Authors: Khosravani Vahid , Samimi Ardestani Seyed Mehdi , Sharifi Bastan Farangis , McKay Dean , Asmundson Gordon J. G.
Published: April 2021

Suicidal ideation is prevalent in patients with obsessive–compulsive disorder (OCD); but, during COVID‐19, it may be increased. The present study aimed to examine the effects of obsessive–compulsive (OC) symptom dimensions and OCD severity on suicidal ideation by considering the role of stress responses in reaction to COVID‐19 in a clinical sample of patients with OCD. In a cross‐sectional study, 304 patients with OCD completed measures of OC symptom dimensions, OCD severity, general mental health (depression and anxiety), and COVID‐19‐related stress. Results showed that after controlling for depression, anxiety, comorbidity, and lifetime suicide attempts, the OC symptom dimensions of responsibility for harm and unacceptable obsessional thoughts as well as general severity had indirect effects on suicidal ideation through the specific stress responses to COVID‐19, including traumatic stress and compulsive checking. The study shows that OCD patients with specific OC symptom dimensions and severe OCD are more likely to have suicidal ideation during the pandemic. Further, the specific stress responses to COVID‐19 may be an underlying mechanism. Clinicians should carefully assess suicidal ideation in patients with OCD who experience responsibility for harm and unacceptable thoughts, particularly during the pandemic.
Teens more likely than young adults to develop SUD after first cannabis use
Authors: Knopf Alison
Published: April 2021

A study from the National Institutes of Health measuring the prevalence of nine substance use disorders (SUDs) after the first substance use in younger people has found a clear association between younger age of first cannabis use and development of other SUDs later. The findings, published at the end of March in JAMA Pediatrics, emphasize what is already well‐known: the vulnerability of young people to SUDs. After first trying cannabis, the percentage of young people aged 12–17 who develop a cannabis‐specific SUD is almost 11%; the percentage of young adults who develop a cannabis‐specific SUD after first use of cannabis at the ages of 18–25 is under 7%. For all SUDs looked at, the prevalence of developing one within a year after first use was about double — or more — for adolescents than for young adults.
Orthotopic Human Metastatic Uveal Melanoma Xenograft Mouse Models: Applications for Understanding the Pathophysiology and Therapeutic Management of Metastatic Uveal Melanoma
Authors: Terai Mizue , Kageyama Ken , Sugase Takahito , Lam Bao Quoc , Alexeev Vitali , Sato Takami
Published: April 2021

The propensity of uveal melanoma to metastasize to the liver hinders the accrual of micro‐metastatic and end‐stage disease tissue samples and restricts the investigation of metastatic uveal melanoma (MUM). Pre‐clinical experimental animal models of MUM can help elucidate the pathophysiology of metastatic lesions and provide a tool for designing new therapeutic approaches for MUM. Here, we present an advanced model of hepatic metastases that enables quantitatively visualizing the development of individual hepatic tumor clones and estimating their growth kinetics and colonization efficiency. Similar to clinically observed liver metastases, these models enable the assessment of growth kinetics of the liver micro‐metastases and the testing of therapeutic approaches for the treatment of MUM. © 2021 Wiley Periodicals LLC.

Basic Protocol 1: Experimental patient‐derived xenograft mouse model of metastatic uveal melanoma

Basic Protocol 2: Experimental liver micro‐metastatic mouse model using splenic injection of metastatic uveal melanoma cells
Karyotype analysis and mode of reproduction of two species of Urochloa P. Beauv.
Authors: Moraes Isabella de Campos , Pereira Welison Andrade , Nani Thaís Furtado , Paula Cristina Maria Pinto de , Rocha Mara Jane da , Souza Sobrinho Fausto , Techio Vania Helena
Published: April 2021

Grasses with desirable traits for agriculture and livestock production are continually being sought. The genus Urochloa comprises many species of good forage potential, although studies have mostly focused on commercial cultivars. Karyotype data can be used to characterize species and generate information for taxonomy and evolutionary studies and contribute to breeding programs. The mode of reproduction is also an essential piece of information to determine breeding strategies. This study aimed to characterize the karyotypes of Urochloa arrecta (Hack. ex T. Dur. & Schniz) O. Morrone & F. Zuloaga and a pentaploid cytotype of U. brizantha (Hochst. ex A. Rich.) R. Webster, including the mapping of ribosomal DNA (rDNA) sites and nuclear DNA content and indicating the mode of reproduction. Slides were prepared using the flame drying technique and were subjected to fluorescent in situ hybridization with 35S and 5S rDNA probes. DNA content was estimated by flow cytometry. The classification of the reproduction mode was based on the amplification of the primers N14 and p779/p780. Urochloa arrecta presented 2C = 2.66 pg of DNA, karyotype formula 2n = 4x = 34 m + 2sm, four chromosomes with 35S rDNA sites, and four other chromosomes with 5S rDNA sites. The absence of amplification products with the primers N14 and p779/p780 provided evidence of sexual reproduction. Urochloa brizantha presented 2C = 4.52 pg of DNA and karyotype formula 2n = 5x = 45 m. Five chromosomes presented 35S rDNA, and eight other chromosomes displayed 5S rDNA sites. Polymerase chain reaction results indicated that this cytotype has an apomictic mode of reproduction. The organization of karyotypes suggests an allopolyploid origin for both genotypes. Possible applications of the information found are discussed.
The effect of the plasma density gradient on current filamentation instability
Authors: Mahdavi M. , Khanzadeh H.
Published: April 2021

The filamentation instability is one of the basic beam‐plasma instabilities that play a significant role in the energy deposition mechanism of the relativistic electrons generated by the laser‐plasma interaction in the fast ignition scenario. In this paper, the effect of the density gradient into plasma on the filamentation instability was investigated in the Weibel unstable plasma, where the plasma temperature anisotropy can play an important role. Results indicated that the density gradient enhances the instability growth rate so that decreasing the density gradient from the critical surface to the core of fuel leads to instability for longer regions in k space. Also, investigations in the region close to the critical surface showed that for decreasing the beam number density nb ≤ 0.01n0, the instability occurs for while this can be different for higher values. Increasing the beam relativistic factor causes a decreasing peak of instability growth rate because of a reduction in beam current, whereas the initial thermal spread of plasma amplifies the filamentation instability.
Low‐cost localization technique for heterogeneous wireless sensor networks
Authors: Nithya B. , Jeyachidra J.
Published: April 2021

In heterogeneous wireless sensor networks (HWSN), the probability‐based node discovery method may result in inaccuracy and time consumption. Also, the adaptive adjustment of transmission range based on overhead and connectivity may result in additional overhead and time. Hence, in this paper, the author proposes to design a low‐cost localization technique using Artificial Bee Colony (ABC) optimization algorithm for HWSN. In this technique, ABC optimization algorithm is applied for deploying the anchor nodes for coverage. Then, the connectivity between the nodes is ensured with minimum transmission power. Since this method involves minimum transmission power level (TPL) and the only minimum set of anchor nodes with strong coverage is involved, it has low‐cost utilizing lower power consumption. By simulation result, it has been shown that the proposed method reduces power consumption leading to low cost.
A high‐gain and low cross‐polarized printed fractal antenna for X‐band wireless application
Authors: Kola Kalyan Sundar , Chatterjee Anirban
Published: April 2021

This paper presents a newly introduced fractal microstrip patch antenna for X‐band wireless application. The proposed fractal printed antenna possesses a fourfold centrosymmetric structure and gives considerably high gain with relatively low cross‐polarization along the entire half‐power beamwidth (HPBW) region of its radiation pattern. The proposed structure has been derived through selectively etching intersection parts between 4 symmetric lens and 13 circle geometries. In order to resonate the structure as well as to reduce the cross‐polarization, three diagonal slots have been etched from its ground plane. The fabricated prototype resonates at 8.49 GHz and gives a gain and impedance bandwidth of 6.98 dBi and 494 MHz, respectively. The measured cross‐polarization of the antenna along the direction of the main beam is −34.28 dB. The measured radiation efficiency and the computed aperture efficiency of the prototype are 91.96% and 78.25%, respectively. The fabricated prototype shows a very good agreement between its simulated and measured results and hence is a suitable candidate for X‐band‐related wireless applications.
An efficient adaptive threshold‐based dragonfly optimization model for cooperative spectrum sensing in cognitive radio networks
Authors: Jothiraj Sivasankari , Balu Sridevi , Rangaraj Neelaveni
Published: April 2021

Effective utilization of spectrum resources is an important factor in wireless communication which reduces spectrum scarcity. Over the years, communication systems use different frequency bands, and the users are categorized into licensed and unlicensed users. Most of the wireless bands are typically licensed; as a result, accommodation of new technologies such as Internet of Things and machine to machine communication becomes difficult. So it is essential to obtain a wireless spectrum to adopt new technologies. Cognitive radio technology is introduced to improve such spectrum utilization. Reports state that most of the licensed spectrums are underutilized, and few spectrums are overutilized. Cognitive radio networks help to exploit the licensed spectrum and access the spectrum without any interference to the licensed user. Through its spectrum sensing and spectrum sharing process, cognitive radio network gains more attention in wireless communication. This research work proposed an efficient optimized spectrum sensing technique for cognitive radio networks through dragonfly optimization algorithm along with the adaptive threshold process. Proposed work performs better in terms of detection accuracy and efficiency when compared to conventional spectrum sensing schemes such as linear support vector machine and particle swarm optimization models.
Overcoming establishment thresholds for peat mosses in human‐made bog pools
Authors: Temmink Ralph J. M. , Cruijsen Peter M. J. M. , Smolders Alfons J. P. , Bouma Tjeerd J. , Fivash Gregory S. , Lengkeek Wouter , Didderen Karin , Lamers Leon P. M. , van der Heide Tjisse
Published: April 2021

Globally, peatlands have been affected by drainage and peat extraction, with adverse effects on their functioning and services. To restore peat‐forming vegetation, drained bogs are being rewetted on a large scale. Although this practice results in higher groundwater levels, unfortunately it often creates deep lakes in parts where peat was extracted to greater depths than the surroundings. Revegetation of these deeper waters by peat mosses appears to be challenging due to strong abiotic feedbacks that keep these systems in an undesired bare state. In this study, we theoretically explore if a floating peat mat and an open human‐made bog lake can be considered two alternative stable states using a simple model, and experimentally test in the field whether stable states are present, and whether a state shift can be accomplished using floating biodegradable structures that mimic buoyant peat. We transplanted two peat moss species into these structures (pioneer sp. Sphagnum cuspidatum and later‐successional sp. S. palustre) with and without additional organic substrate. Our model suggests that these open human‐made bog lakes and floating peat mats can indeed be regarded as alternative stable states. Natural recovery by spontaneous peat moss growth, i.e., a state shift from open water to floating mats, is only possible when the water table is sufficiently shallow to avoid light limitation (<0.29 m at our site). Our experiment revealed that alternative stable states are present and that the floating structures facilitated the growth of pioneer S. cuspidatum and vascular plants. Organic substrate addition particularly facilitated vascular plant growth, which correlated to higher moss height. The structures remained too wet for the late‐successional species S. palustre. We conclude that open water and floating peat mats in human‐made bog lakes can be considered two alternative stable states, and that temporary floating establishment structures can induce a state shift from the open water state to peat‐forming vegetation state. These findings imply that for successful restoration, there is a clear water depth threshold to enable peat moss growth and there is no need for addition of large amounts of donor‐peat substrate. Correct species selection for restoration is crucial for success.
Predicting anoxia in low‐nutrient temperate lakes
Authors: Deeds Jeremy , Amirbahman Aria , Norton Stephen A. , Suitor Douglas G. , Bacon Linda C.
Published: April 2021

Absence of dissolved oxygen (anoxia) in the hypolimnion of lakes can eliminate habitat for sensitive species and may induce the release of sediment‐bound phosphorus. Lake anoxia generally results from decomposition of organic matter, which is exacerbated by high nutrient loads. Total phosphorus (TP) in lakes is regulated by static aspects of the lake’s watershed, but lake TP can be readily increased by human activities. In some low‐nutrient lakes, basin morphometry may induce naturally occurring anoxia. The occurrence of natural anoxia is especially important to consider in lake water quality assessments that compare observed conditions to expected reference conditions. To investigate the occurrence of natural vs. anthropogenically influenced anoxia, we constructed a logistic regression model to calculate the probability of low‐nutrient lakes (TP < 15 µg/L) developing aerial anoxic extent ≥10% by testing the predictive potential of variables related to basin morphometry, depths of lake thermal strata, epilimnetic TP, and dissolved organic carbon (DOC). Maximum lake depth and the proportion of lake area under the top of the metalimnion were the most important variables to predict the likelihood of hypolimnetic anoxia, which correctly predicted anoxic condition in 84% of lakes (Model 1). Adding TP as a third variable to Model 1 produced a significantly improved model (Model 2) but the prediction success rate was comparable (86%). We also present a model for lakes with limited bathymetric data, which predicts anoxia with 81% accuracy based on maximum lake depth and mean thermocline depth at peak stratification. DOC was relatively low (4.3 ± 1.5 mg/L [mean ± SD]) in the study lakes and its inclusion did not improve model performance. In Model 1, lakes with an anoxic extent ≥10% of lake area had significantly higher epilimnetic TP than lakes with oxic hypolimnia, regardless of prediction category or success. Our results indicate that including TP as a variable helps refine models based on morphometry alone, but lake morphometry and stratification dynamics are the most important factors in the development of anoxic extent in low‐nutrient temperate lakes. Our approach informs studies concerned with identifying key factors that influence regime shifts in a variety of ecosystems.
Food insecurity associated with elevated eating disorder symptoms, impairment, and eating disorder diagnoses in an American University student sample before and during the beginning of the COVID‐19 pandemic
Authors: Christensen Kara A. , Forbush Kelsie T. , Richson Brianne N. , Thomeczek Marianna L. , Perko Victoria L. , Bjorlie Kayla , Christian Kylie , Ayres Joseph , Wildes Jennifer E. , Mildrum Chana Sofia
Published: April 2021

Objective

This study tested the association between food insecurity and eating disorder (ED) pathology, including probable ED diagnosis, among two cohorts of university students before and during the beginning of the COVID‐19 pandemic.

Method

Students (n = 579) from a large Midwestern American university completed self‐report questionnaires assessing frequency of ED behaviors, ED‐related impairment, and individual food insecurity as measured by the Eating Disorder Diagnostic Scale 5, Clinical Impairment Assessment, and Radimer/Cornell, respectively. Chi‐square tests and MANOVA with post‐hoc corrections were conducted to compare demographic characteristics, ED pathology, and probable ED diagnosis prevalence between students with and without individual food insecurity.

Results

Partially supporting hypotheses, MANOVA indicated significantly greater frequency of objective binge eating, compensatory fasting, and ED‐related impairment for students with food insecurity compared with individuals without food insecurity. Chi‐squared tests showed higher prevalence of ED diagnoses among individuals with food insecurity compared with those without food security (47.6 vs. 31.1%, respectively, p < .01, NNT = 6.06), specifically bulimia nervosa and other specified feeding and eating disorder. There were no differences in food insecurity before or during the beginning of the COVID‐19 pandemic.

Discussion

Consistent with prior literature, food insecurity was associated with elevated ED psychopathology in this sample. Findings emphasize the importance of proper ED screening for college students vulnerable to food insecurity and EDs.
Benefit of a wearable cardioverter defibrillator for detection and therapy of arrhythmias in patients with myocarditis
Authors: Tscholl Verena , Wielander Dennis , Kelch Felicitas , Stroux Andrea , Attanasio Philipp , Tschöpe Carsten , Landmesser Ulf , Roser Mattias , Huemer Martin , Heidecker Bettina , Nagel Patrick
Published: April 2021

Aims

Myocarditis may lead to malignant arrhythmias and sudden cardiac death. As of today, there are no reliable predictors to identify individuals at risk for these catastrophic events. The aim of this study was to evaluate if a wearable cardioverter defibrillator (WCD) may detect and treat such arrhythmias adequately in the peracute setting of myocarditis.

Methods and results

In this observational, retrospective, single centre study, we reviewed patients presenting to the Charité Hospital from 2009 to 2017, who were provided with a WCD for the diagnosis of myocarditis with reduced ejection fraction (<50%) and/or arrhythmias. Amongst 259 patients receiving a WCD, 59 patients (23%) were diagnosed with myocarditis by histology. The mean age was 46 ± 14 years, and 11 patients were women (19%). The mean WCD wearing time was 86 ± 63 days, and the mean daily use was 20 ± 5 h. During that time, two patients (3%) had episodes of sustained ventricular tachycardia (VT; four total) corresponding to a rate of 28 sustained VT episodes per 100 patient‐years. Consequently, one of these patients underwent rhythm stabilization through intravenous amiodarone, while the other patient received an implantable cardioverter defibrillator. Two patients (3.4%) were found to have non‐sustained VT.

Conclusions

Using a WCD after acute myocarditis led to the detection of sustained VT in 2/59 patients (3%). While a WCD may prevent sudden cardiac death after myocarditis, our data suggest that WCD may have impact on clinical management through monitoring and arrhythmia detection.
Synthesis and Electrochemical Properties of Hierarchical Porous (Nickel/Cobalt)‐Carbonate‐Hydroxide Structures
Authors: Shu Chuankang , Liang Ying , Zhang Zhen , Fang Bin
Published: April 2021

Hierarchical porous Ni3(CO3)(OH)4 and (NixCo1‐x)6(CO3)2(OH)8 ⋅ H2O (x=0, 1/3, 1/2, and 2/3) structures have been synthesized via a hydrothermal route. The chloride ions in the precursor play an important role in the morphology of (Ni,Co)6(CO3)2(OH)8 ⋅ H2O. The formation mechanism and growth process of urchin‐like (Ni,Co)6(CO3)2(OH)8 ⋅ H2O structure was investigated by adjusting the reaction time. The electrochemical properties of the products depend on the chemical composition and surface property. Ni3(CO3)(OH)4 exhibits higher specific capacitance at a low current density due to its porous structure and larger specific surface area. However, its rate property and cycle stability are much poorer. Co6(CO3)2(OH)8 ⋅ H2O nanorod‐assembled structure possesses better cyclic performance but lower specific capacitance. (Ni,Co)6(CO3)2(OH)8 ⋅ H2O electrodes behave improved rate property and cycle stability in comparison with Ni3(CO3)(OH)4, and higher specific capacitance than Co6(CO3)2(OH)8 ⋅ H2O, which can be attributed to the synergistic effect of bimetal species and unique surface property.
Trimethylsilyl Pseudohalide Adducts of GaCl3 and B(C6F5)3
Authors: Bläsing Kevin , Bresien Jonas , Maurer Steffen , Schulz Axel , Villinger Alexander
Published: April 2021

Me3Si−X (X=CN, N3, OCN, and SCN) was treated with the Lewis acids GaCl3 and B(C6F5)3 in toluene yielding the desired adducts Me3Si−X→GaCl3 and Me3Si−X→B(C6F5)3. All synthesized adducts were isolated and completely characterized including single crystal structure elucidations. The different structures, thermodynamics of formation and charge transfer effects are discussed on the basis of experimental and theoretical data.
Voltammetric Analysis of Oxymetazoline Hydrochloride at Zeolite – Modified Carbon Paste Electrode in Micellar Medium
Authors: Hussien Emad M. , Rizk Mohamed , Daoud Amira M. , El‐Eryan Rasha Th.
Published: April 2021

Simple, sensitive, accurate and inexpensive differential pulse (DPV) and square wave (SWV) voltammetric methods utilizing zeolite modified carbon paste electrode (ZMCPE) were developed for the determination of Oxymetazoline hydrochloride (OXM) in nasal drops. Various experimental parameters were optimized using cyclic voltammetry (CV). Calibration curves were linear over the concentration ranges 9.8×10−8–3.6×10−6 M and 9.8×10−6–9×10−5 M for DPV and SWV, respectively. The DPV method showed a limit of detection (LOD) of 1.04×10−7 M. The method was applied for the determination of OXM in pharmaceutical formulation with an average recovery of 101.18 % (%RSD=0.41, n=9).
Effects of exogenous gibberellic acid on growth and cadmium accumulation in Cyphomandra betacea seedlings
Authors: Yang Liu , Huan Yunmin , Sun Jing , Lin Lijin , Liao Ming'an , Wang Zhihui , Liang Dong , Xia Hui , Lv Xiulan , Wang Jin
Published: April 2021

The contamination of orchards by the heavy metal cadmium (Cd) is a serious problem partly because of the toxicity of the Cd accumulated in fruits. Accordingly, developing suitable methods for minimizing the toxic effects of Cd on plants is necessary. In the current study, a pot‐based experiment was conducted to assess the effects of various concentrations (0, 100, 200, 300, and 400 mg/L) of exogenous gibberellic acid (GA) on the growth and Cd accumulation in Cyphomandra betacea seedlings. The GA treatments promoted C. betacea seedling growth and increased the biomass as well as the chlorophyll, carotenoid, and soluble sugar contents. Additionally, the application of GA, especially the 300 mg/L solution, enhanced the net photosynthetic rate, stomatal conductance, the intercellular CO2 concentration, the transpiration rate, and the peroxidase, superoxide dismutase, and catalase activities. In contrast, the Cd content of C. betacea seedlings gradually decreased in response to increasing exogenous GA concentrations. Thus, the application of a GA solution improved C. betacea seedling growth and decreased the toxicity of Cd, with 300 mg/L representing the most effective GA concentration.
A stable discontinuous Galerkin method based on high‐order dual splitting scheme without additional stabilization term for incompressible flows
Authors: Ma Mengxia , Ouyang Jie , Wang Xiaodong , Zhang Chenhui
Published: April 2021

In this work, we consider equal‐order discontinuous Galerkin (DG) solver for incompressible Navier–Stokes equations based on high‐order dual splitting scheme. In order to stay stable, the time step size of this method has been reported that is strictly limited. The upper bound of time step size is restricted by Courant–Friedrichs–Lewy (CFL) condition (Hesthaven and Warburton, 2007) and lower bound is required to be larger than the critical value which depends on Reynolds number and spatial resolution (Ferrer et al., 2014). For high‐Reynolds‐number flow problems, if the spatial resolution is low, the critical value may be larger than CFL condition, then instability will occur for any time step size. Therefore, sufficiently high spatial resolution is indispensable in order to maintain stability, which increases the computational cost. To overcome these difficulties and develop a robust solver for high‐Reynolds‐number flow problem, it is necessary to further study the instability problem at small time steps. We numerically investigate the effect of the pressure gradient term in projection step and the velocity divergence term in pressure Poisson equation on the stability for small time step size, respectively, and conclude that the DG formulation of the pressure gradient term has a more significant effect on the stability of the scheme than that of the velocity divergence term. Integration by parts of these terms is essential in order to improve the stability of the scheme. Based on this discretization format, an appropriate penalty parameter for pressure Poisson equation is utilized so as to provide the scheme with an inf‐sup stabilization. Moreover, the lid‐driven cavity flow is considered to verify that this numerical algorithm enhances the stability without additional stabilization term at small time step size and high‐Reynolds number for equal‐order polynomial approximations.
History and Bioethics
Authors: Fins Joseph J.
Published: April 2021

Cultural historians and historians of medicine are a rarity in bioethics. Even those who write histories of bioethics are philosophers, sociologists, or theologians. Where have all the historians gone? If bioethics is to contribute to the urgent work of addressing social justice, structural racism, and health inequity, we bioethicists need to embrace history as a fully constituent part of our field. Historians can help us apprehend the ideas that shaped bioethics, and health policy more broadly, and discover the dissenting arguments that might inspire us now. Given our annus horribilis, history has become an instrumental necessity. It is only through the study of history that we can understand the past so as to reimagine how bioethics can influence health policy and work toward health equity.
Public Engagement and the Social Risks of Science
Authors: Resnik David B.
Published: April 2021

This letter responds to the article “The Social Risks of Science,” by Jonathan Herington and Scott Tanona, published in the November‐December 2020 issue of the Hastings Center Report.
Teneille Brown, Leslie Francis, and James Tabery respond
Authors: Brown Teneille , Francis Leslie , Tabery James
Published: April 2021

This is a response to the letter to the editor “Prioritizing the Prevention of Early Deaths during Covid‐19,” by Govind Persad.
Coming to Terms with the Black Box Problem: How to Justify AI Systems in Health Care
Authors: Felder Ryan Marshall
Published: April 2021

The use of opaque, uninterpretable artificial intelligence systems in health care can be medically beneficial, but it is often viewed as potentially morally problematic on account of this opacity—because the systems are black boxes. Alex John London has recently argued that opacity is not generally problematic, given that many standard therapies are explanatorily opaque and that we can rely on statistical validation of the systems in deciding whether to implement them. But is statistical validation sufficient to justify implementation of these AI systems in health care, or is it merely one of the necessary criteria? I argue that accountability, which holds an important role in preserving the patient‐physician trust that allows the institution of medicine to function, contributes further to an account of AI system justification. Hence, I endorse the vanishing accountability principle: accountability in medicine, in addition to statistical validation, must be preserved. AI systems that introduce problematic gaps in accountability should not be implemented.