bluuebunny/crossref_metadata_2025 huggingface dataset:
Registration of three new bmr12 sorghum mutants from an ethyl methane sulfonate–induced BTx623 mutant population
Authors: Emendack Yves , Xin Zhanguo , Hayes Chad , Burow Gloria , Sattler Scott , Bean Scott , Smolensky Dmitriy
Published: April 2022

Three new sorghum (Sorghum bicolor L.) brown midrib (bmr) genetic stocks BTx623bmr12‐30 (Reg. no. GS‐790, PI 699404), BTx623bmr12‐34 (Reg. no. GS‐789, PI 699405), and BTx623bmr12‐35 (Reg. no. GS‐788, PI 699406) were developed for release by USDA–ARS in Lubbock, TX. The primary purpose for the release of these stocks is to provide an extensive source of (bmr12) variants for use in forage breeding programs. The genetic stocks were isolated from the pedigreed sorghum ethyl methane sulfonate–mutagenized sorghum in BTx623 background. The derived mutations were analyzed by DNA sequencing and confirmed by KASP (Kompetitive Allele Specific PCR) markers. The confirmed bmr mutants were also analyzed for stem and leaf lignin and carbohydrate contents. Furthermore, physiological and agro‐morphological evaluations were performed under control and field conditions. All genetic stocks displayed the reddish‐brown pigmentation in the leaf midrib, confirming the bmr phenotype. The bmr12 mutants flowered 4–5 d earlier than the wild type BTx623. Physical and compositional characterization of seeds from the three genetic stocks revealed no negative consequence of bmr on grain structure. Notably, these bmr12 mutants had 14–24% greater total seed protein than wild type BTx623. The three new bmr12 alleles provide public and private breeders crucial and novel genetic stock sources for use in breeding bmr forage sorghum.
A novel 3D X‐ray computed tomography (CT) method for spatio‐temporal evaluation of waterlogging‐induced aerenchyma formation in barley
Authors: Kehoe Stephen , Byrne Tomás , Spink John , Barth Susanne , Ng Carl K. Y. , Tracy Saoirse
Published: April 2022

Increased precipitation during winter months in Western Europe is predicted from climate change. This is expected to increase the frequency of flooding events, with waterlogged conditions becoming more prevalent. A consequence of waterlogging is hypoxic conditions and dying back of roots, thereby negatively affecting plant nutrient uptake, growth, and development. Barley (Hordeum vulgare L.) forms lysigenous aerenchyma, which are air‐filled pockets within the root to facilitate O2 transport and support root respiration. Current methods for visualizing aerenchyma formation in roots are largely 2D and involve embedding a fixed root segment in resin, followed by destructive sectioning for microscopy. Here, we report the development of an X‐ray computed tomography (CT) acquisition and analytical method for spatio‐temporal identification and quantitation of aerenchyma in 2D and 3D in barley roots without the requirement for chemical fixation, resin embedding, followed by physical sectioning of the root. We demonstrated that the method we have developed can facilitate the identification and quantitation of aerenchyma in barley as early as 9 d post‐waterlogging. The method we have developed can be potentially applied to different plant species and has the potential to support the selection of breeding markers through X‐ray CT phenotyping of aerenchyma.
Impact of inspiratory muscle strength on exercise capacity after lung transplantation
Authors: Sato Tatsuya , Sato Susumu , Oshima Yohei , Yoshioka Yuji , Hamada Ryota , Nankaku Manabu , Ikeda Masaki , Nakajima Daisuke , Chen‐Yoshikawa Toyofumi F. , Date Hiroshi , Matsuda Shuichi , Tabira Kazuyuki
Published: April 2022

Background and Purpose

Though inspiratory muscle strength is essential for patients with respiratory disease, it is unclear whether the recovery of inspiratory muscle strength contributes to an exemplary achievement of exercise tolerance after lung transplantation (LTx). We aimed to elucidate the inspiratory muscle strength affects the recovery of exercise capacity after LTx.

Methods

Recipients who underwent LTx between June 2017 and September 2018 were enrolled, and 6‐min walking distance (6MWD), quadriceps force, inspiratory muscle strength (maximal inspiratory pressure [MIP]), and spirometry were evaluated at 3, 6, and 12 months after LTx. The relationships between inspiratory muscle strength and changes in physical performance were analyzed.

Results

Nineteen recipients (mean age: 44.8 years, male: 32%) who completed all follow‐ups were analyzed. At 3 months after LTx, mean MIP (88.4% predicted) and vital capacity (60.9% predicted), quadriceps force (QF; 2.1 N*m/kg), and 6MWD (504 m) were lower than normal values. After LTx, 6MWD significantly improved up to 12 months. From 3 to 6 months after LTx, changes in MIP were significantly associated with increases in 6MWD by univariate (r = 0.55, p = 0.02) and multivariate (β = 0.59, p = 0.01) regression analyses, whereas changes of QF in place of MIP were significantly associated with the recoveries of 6MWD from 6 to 12 months.

Discussion

Improvements in MIP may impact the recovery of exercise capacity in the early phase after LTx. Factors that determine the improvement in exercise capacity following LTx may vary with postoperative time.
Structural insights into DNA binding domain of vancomycin‐resistance‐associated response regulator in complex with its promoter DNA from Staphylococcus aureus
Authors: Kumar Jangam Vikram , Tseng Tien‐Sheng , Lou Yuan‐Chao , Wei Shu‐Yi , Wu Tsung‐Han , Tang Hao‐Cheng , Chiu Yi‐Chih , Hsu Chun‐Hua , Chen Chinpan
Published: April 2022

In Staphylococcus aureus, vancomycin‐resistance‐associated response regulator (VraR) is a part of the VraSR two‐component system, which is responsible for activating a cell wall‐stress stimulon in response to an antibiotic that inhibits cell wall formation. Two VraR‐binding sites have been identified: R1 and R2 in the vraSR operon control region. However, the binding of VraR to a promoter DNA enhancing downstream gene expression remains unclear. VraR contains a conserved N‐terminal receiver domain (VraRN) connected to a C‐terminal DNA binding domain (VraRC) with a flexible linker. Here, we present the crystal structure of VraRC alone and in complex with R1‐DNA in 1.87‐ and 2.0‐Å resolution, respectively. VraRC consisting of four α‐helices forms a dimer when interacting with R1‐DNA. In the VraRC–DNA complex structure, Mg2+ ion is bound to Asp194. Biolayer interferometry experiments revealed that the addition of Mg2+ to VraRC enhanced its DNA binding affinity by eightfold. In addition, interpretation of NMR titrations between VraRC with R1‐ and R2‐DNA revealed the essential residues that might play a crucial role in interacting with DNA of the vraSR operon. The structural information could help in designing and screening potential therapeutics/inhibitors to deal with antibiotic‐resistant S. aureus via targeting VraR.
Desiccation‐tolerance and globular proteins adsorb similar amounts of water
Authors: Brom Julia A. , Pielak Gary J.
Published: April 2022

When exposed to desiccation stress, extremotolerant organisms from all domains of life produce protective disordered proteins with the potential to inform the design of excipients for formulating biologics and industrial enzymes. However, the mechanism(s) of desiccation protection remain largely unknown. To investigate the role of water sorption in desiccation protection, we use thermogravimetric analysis to study water adsorption by two desiccation‐tolerance proteins, cytosolic abundant heat soluble protein D from tardigrades and late embryogenesis abundant protein 4 from the anhydrobiotic midge Polypedilum vanderplanki, and, as a control, the globular B1 domain of staphylococcal protein G. All samples adsorb similar amounts of water, suggesting that modulated water retention is not responsible for dehydration protection by desiccation‐tolerance proteins.
Structure–function analysis of cysteine residues in the plasmodium falciparum chitinase, PfCHT1
Authors: Kaur Hargobinder , Garber Laine , Murphy James W. , Vinetz Joseph M.
Published: April 2022

The Plasmodium ookinete uses chitinase activity to penetrate the acellular, chitin‐containing peritrophic matrix to invade the mosquito vector. Plasmodium ookinetes from different parasite clades secrete two structurally distinct forms of chitinase, one, a short form lacking a C‐terminal putative chitin‐binding domain (CBD), the other, a long form with both proenzyme and C‐terminal putative chitin‐binding domains. Here, we structurally and functionally characterize the three cysteines in the short chitinase of the human‐infecting malaria parasite, P. falciparum testing the hypothesis that one unpaired cysteine would not contribute to chitinase‐specific enzymatic activity which would identify this residue as potentially involved in intermolecular disulfide bonding and heteromultimeric invasion complex formation as previously described. To test this hypothesis, we produced and characterized recombinant wild‐type and cysteine‐mutation PfCHT1 proteins in E. coli and used biophysical and enzymatic approaches to examine their enzymatic activities and chitin‐binding affinities. The cysteine‐203 PfCHT1 mutation had no effect on chitinolytic and chitin‐binding functions. The cysteine‐220 and cysteine‐230 mutants were enzymatically inactive and did not bind to chitin. The artificial intelligence‐based protein prediction algorithm, AlphaFold, correctly identified the involvement of cys‐220 and cys‐230 in the intramolecular disulfide linkages key to maintaining properly folded chitinase structural integrity. AlphaFold predicted that cys‐203 cysteine is surface exposed and thus involved in intermolecular protein–protein interaction. Production of the cys‐to‐ser 203 PfCHT1 mutant facilitated recombinant protein production. Future cellular and biochemical studies are needed to further understand details of Plasmodium ookinete mosquito midgut invasion.
Characterization of the glutathione‐dependent reduction of the peroxiredoxin 5 homolog PfAOP from Plasmodium falciparum
Authors: Schumann Robin , Lang Lukas , Deponte Marcel
Published: April 2022

Peroxiredoxins use a variety of thiols to rapidly reduce hydroperoxides and peroxynitrite. While the oxidation kinetics of peroxiredoxins have been studied in great detail, enzyme‐specific differences regarding peroxiredoxin reduction and the overall rate‐limiting step under physiological conditions often remain to be deciphered. The 1‐Cys peroxiredoxin 5 homolog PfAOP from the malaria parasite Plasmodium falciparum is an established model enzyme for glutathione/glutaredoxin‐dependent peroxiredoxins. Here, we reconstituted the catalytic cycle of PfAOP in vitro and analyzed the reaction between oxidized PfAOP and reduced glutathione (GSH) using molecular docking and stopped‐flow measurements. Molecular docking revealed that oxidized PfAOP has to adopt a locally unfolded conformation to react with GSH. Furthermore, we determined a second‐order rate constant of 6 × 105 M−1 s−1 at 25°C and thermodynamic activation parameters ΔH‡, ΔS‡, and ΔG‡ of 39.8 kJ/mol, −0.8 J/mol, and 40.0 kJ/mol, respectively. The gain‐of‐function mutant PfAOPL109M had almost identical reaction parameters. Taking into account physiological hydroperoxide and GSH concentrations, we suggest (a) that the reaction between oxidized PfAOP and GSH might be even faster than the formation of the sulfenic acid in vivo, and (b) that conformational changes are likely rate limiting for PfAOP catalysis. In summary, we characterized and quantified the reaction between GSH and the model enzyme PfAOP, thus providing detailed insights regarding the reactivity of its sulfenic acid and the versatile chemistry of peroxiredoxins.
Electrostatic fingerprints of catalytically active amino acids in enzymes
Authors: Iyengar Suhasini M. , Barnsley Kelly K. , Xu Rholee , Prystupa Aleksandr , Ondrechen Mary Jo
Published: April 2022

The computed electrostatic and proton transfer properties are studied for 20 enzymes that represent all six major enzyme commission classes and a variety of different folds. The properties of aspartate, glutamate, and lysine residues that have been previously experimentally determined to be catalytically active are reported. The catalytic aspartate and glutamate residues studied here are strongly coupled to at least one other aspartate or glutamate residue and often to multiple other carboxylate residues with intrinsic pKa differences less than 1 pH unit. Sometimes these catalytic acidic residues are also coupled to a histidine residue, such that the intrinsic pKa of the acidic residue is higher than that of the histidine. All catalytic lysine residues studied here are strongly coupled to tyrosine or cysteine residues, wherein the intrinsic pKa of the anion‐forming residue is higher than that of the lysine. Some catalytic lysines are also coupled to other lysines with intrinsic pKa differences within 1 pH unit. Some evidence of the possible types of interactions that facilitate nucleophilicity is discussed. The interactions reported here provide important clues about how side chain functional groups that are weak Brønsted acids or bases for the free amino acid in solution can achieve catalytic potency and become strong acids, bases or nucleophiles in the enzymatic environment.
Structure and DNA binding analysis of AT‐rich interaction domain present in human BAF‐B specific subunit BAF250b
Authors: Giri Malyasree , Gupta Parul , Maulik Aditi , Gracias Magaly , Singh Mahavir
Published: April 2022

BAF250b and its paralog BAF250a are the DNA‐binding central hub proteins present in BAF‐B and BAF‐A classes of SWI/SNF chromatin‐remodeling complexes. BAF250b contains an AT‐rich interaction domain (ARID) and C‐terminal BAF250_C domain, and it is found mutated in several cancers. ARID is a conserved helix‐turn‐helix motif‐containing DNA‐binding domain present in several eukaryotic proteins. The ARID of BAF250b has been proposed to play roles in recruiting SWI/SNF to the target gene promoters for their activation. BAF250b ARID structures had been deposited in the protein data bank by a structural genomics consortium. However, it is not well‐studied for its DNA‐binding and solution dynamic properties. Here, we report complete backbone NMR resonance assignments of human BAF250b ARID. NMR chemical shifts and the backbone dynamics showed that the solution structure of the protein matched the reported crystal structures. The structure and chemical shift indexing revealed the presence of a short β‐sheet in the DNA‐binding region of BAF250b ARID that was absent in the structure of its paralog BAF250a ARID. NMR chemical shift perturbations identified DNA‐binding residues and revealed the DNA‐binding interface on BAF250b ARID. NMR data‐driven HADDOCK models of BAF250b ARID – DNA complexes revealed its plausible mode of DNA‐binding. Isothermal titration calorimetry experiments showed that BAF250b ARID interacts with DNA sequences with moderate affinities like BAF250a ARID. However, distinct thermodynamic signatures were observed for binding of BAF250a ARID and BAF250b ARID to AT‐rich DNA sequence, suggesting that subtle sequence and structural differences in these two proteins influence their DNA‐binding.
Evolutionary origin and sequence signatures of the heterodimeric ABCG5/ABCG8 transporter
Authors: Pei Jimin , Cong Qian
Published: April 2022

ATP‐binding cassette (ABC) systems, characterized by ABC‐type nucleotide‐binding domains (NBDs), play crucial roles in various aspects of human physiology. Human ABCG5 and ABCG8 form a heterodimeric transporter that functions in the efflux of sterols. We used sequence similarity search, multiple sequence alignment, phylogenetic analysis, and structure comparison to study the evolutionary origin and sequence signatures of ABCG5 and ABCG8. Orthologs of ABCG5 and ABCG8, supported by phylogenetic analysis and signature residues, were identified in bilaterian animals, Filasterea, Fungi, and Amoebozoa. Such a phylogenetic distribution suggests that ABCG5 and ABCG8 could have originated in the last common ancestor of Amorphea (the unikonts), the eukaryotic group including Amoebozoa and Opisthokonta. ABCG5 and ABCG8 were missing in genomes of various lineages such as snakes, jawless vertebrates, non‐vertebrate chordates, echinoderms, and basal metazoan groups. Amino‐acid changes in key positions in ABCG8 Walker A motif and/or ABCG5 C‐loop were observed in most tetrapod organisms, likely resulted in the loss of ATPase activity at one nucleotide‐binding site. ABCG5 and ABCG8 in Ecdysozoa (such as insects) exhibit elevated evolutionary rates and accumulate various changes in their NBD functional motifs. Alignment inspection revealed several residue positions that show different amino‐acid usages in ABCG5/ABCG8 compared to other ABCG subfamily proteins. These residues were mapped to the structural cores of transmembrane domains (TMDs), the NBD‐TMD interface, and the interface between TMDs. They serve as sequence signatures to differentiate ABCG5/ABCG8 from other ABCG subfamily proteins, and some of them may contribute to substrate specificity of the ABCG5/ABCG8 transporter.
Effects of X‐ray irradiation on the fitness of the established invasive pest fall armywormSpodoptera frugiperda
Authors: Jiang Shan , He Li‐Mei , He Wei , Zhao Hui‐Yuan , Yang Xian‐Ming , Yang Xue‐Qing , Wu Kong‐Ming
Published: April 2022

BACKGROUND

Spodoptera frugiperdahas spread to Africa, Asia, and Oceania, posing a serious threat to global agriculture. We estimated the appropriate dose of X‐ray sterilization forS. frugiperdausing an X‐ray irradiation instrument to investigate environmentally acceptable control techniques, laying the framework for future applications of sterile insect technology (SIT) to manage the pest environmentally‐friendly.

RESULTS

This study is the first to investigate the effects of X‐ray irradiation on the growth, development, survival, reproduction, and flight ofS. frugiperda. The results showed that irradiation with 50–400 Gy had no significant effect on pupal eclosion, but females were more sensitive than males in terms of reproductive parameters, especially when doses of radiation were > 350 Gy. After irradiation with a sub‐sterilizing dose of 250 Gy, the parental sterility rate was > 85%, and the sterility traits could be passed on to their offspring, resulting in a continuous decrease in the population of F1and F2generations.

CONCLUSION

Our laboratory experiments theoretically confirmed the feasibility of SIT for controllingS. frugiperdain the field using X‐ray radiation. This study provides a theoretical basis for future regional pest management strategies. © 2022 Society of Chemical Industry.
Screening for insecticide resistance in Australian field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) using bioassays and DNA sequencing
Authors: Fang Cao , Hopkinson Jamie E , Balzer Jacob , Frese Michael , Tay Wee Tek , Walsh Thomas
Published: April 2022

Background

Species within the Bemisia tabaci cryptic species complex can cause significant crop damage. We used high‐throughput amplicon sequencing to identify the species composition and resistance allele genotypes in field populations from cotton fields in Australia. For selected populations, the resistance phenotype was determined in bioassays and compared with sequencing data.

Results

A metabarcoding approach was used to analyse the species composition in 144 field populations collected between 2013 and 2021. Two mixed AUS I and MEAM1 populations were detected, whereas the remaining 142 populations consisted of MEAM1 only. High‐throughput sequencing of organophosphate and pyrethroid resistance gene amplicons showed that the organophosphate resistance allele F331W was fixed (> 99%) in all MEAM1 populations, whereas the pyrethroid resistance allele L925I in the voltage‐gated sodium channel gene was detected at varying frequencies [1.0%–7.0% (43 populations); 27.7% and 42.1% (two populations); 95%–97.5% (three populations)]. Neither organophosphate nor pyrethroid resistance alleles were detected in the AUS I populations. Pyrethroid bioassays of 85 MEAM1 field‐derived populations detected no resistance in 51 populations, whereas 32 populations showed low frequency resistance, and 2 populations were highly resistant.

Conclusions

We demonstrate that high‐throughput sequencing and bioassays are complementary approaches. The detection of target site mutations and the phenotypic provides a comprehensive analysis of the low‐level resistance to pyrethroids that is present in Australian cotton farms. By contrast, a limited survey of whitefly populations from horticulture found evidence of high‐level resistance against pyrethroids. Furthermore, we found that the F331W allele (linked to organophosphate resistance) is ubiquitous in Australian MEAM1. © 2022 Commonwealth of Australia. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
TGF‐β receptor mutations and clinical prognosis in Chinese pediatric patients with idiopathic/hereditary pulmonary arterial hypertension
Authors: Zhang Xinyu , Zhang Chen , Li Qiangqiang , Gu Hong
Published: April 2022

The relationship between clinical prognosis and transforming growth factor‐β (TGF‐β) receptor mutations in Chinese pediatric patients with idiopathic/hereditary pulmonary arterial hypertension (IPAH/HPAH) remains unclear. We retrospectively studied the clinical characteristics and outcomes of pediatric patients with IPAH/HPAH who visited our Hospital from September 2008 to December 2020. One hundred and five pediatric patients with IPAH/HPAH were included, 46 of whom carried TGF‐β receptor mutations with a mean age at diagnosis of 82.8 ± 52.7 months, and 67 of them underwent right cardiac catheterization examinations and acute vasodilator testing. The result showed that mutation carriers demonstrated higher pulmonary vascular resistance (p = 0.012), higher right atrial pressure (p = 0.026), and lower cardiac index (p = 0.003). The 1‐, 2‐, and 3‐year survival rates of mutation carriers were 79.4%, 61.5% and 55.6%, respectively, compared with 96.6%, 91.1%, and 85.4% for nonmutation carriers (p = 0.0001). The prognosis of mutation carriers was significantly worse than that of nonmutation carriers. TGF‐β receptor gene mutation is an independent risk factor for death (p = 0.049, odd raito = 3.809, 95% confidence interval 1.006−14.429). In conclusion, TGF‐β receptor mutation is an important genetic factor for the onset of IPAH/PAH in Chinese pediatric patients. Those who carrying TGF‐β receptor mutations have a poor clinical prognosis. Therefore, TGF‐β receptor gene screening for pediatric patients with PAH and more aggressive treatment for mutation carriers are recommended.
Maternal and fetal outcomes of pregnant women with pulmonary arterial hypertension associated with congenital heart disease in Beijing, China: A retrospective study
Authors: Liu Yang , Li Yanna , Zhang Jun , Zhang Dawei , Li Jiachen , Zhao Yichen , Liu Kemin , Ma Xiaolong , Bai Chen , Gu Hong , Fan Xiangming , Wang Jiangang
Published: April 2022

As pulmonary arterial hypertension associated with congenital heart disease (PAH‐CHD) may increase maternal and fetal risk, this study explored the pregnancy outcomes of Chinese women with PAH‐CHD. The clinical data of pregnant women with PAH‐CHD admitted to the Beijing Anzhen Hospital from 2010 to 2019 were retrospectively analyzed; these patients and their offspring were followed up, with a mean period of 5.9 ± 2.7 years. Overall, 260 patients with PAH‐CHD were included. The mean maternal age was 27.7 ± 4.1 years, and 205 (78.8%) patients were nulliparous. The estimated systolic pulmonary artery pressure was 40–50 mmHg in 34.6% of the patients, 50–70 mmHg in 23.1%, and >70 mmHg in 42.3%. More than 96% of patients were diagnosed with PAH‐CHD before pregnancy. During pregnancy, heart failure occurred in 19.2% of the patients. Cesarean delivery was performed in 88.1% (15.0% emergency) of the patients. Complications included fetal distress (5.8%), preterm delivery (34.2%), and low birth weight (33.8%). A total of 15 mothers (5.8%) died, with the highest mortality rate in those with Eisenmenger syndrome (10/43, 23.3%), and 10 offspring died (3.8%), two (0.8%) following hospital discharge and eight (3.1%) while in hospital. Although most pregnant women with PAH‐CHD were able to have children, PAH increased the maternal and fetal risk. Thus, an individualized risk‐based approach with shared decision‐making may be more appropriate in pregnant women with PAH‐CHD.
Right heart thrombi (RHT) and clot in transit with concomitant PE management: Approach and considerations
Authors: Khosla Akhil , Mojibian Hamid , Assi Roland , Tantawy Hossam , Singh Inderjit , Pollak Jeffrey
Published: April 2022

Right heart thrombi (RHT) continues to pose a clinical dilemma for multiple specialties and is especially concerning when present with concomitant pulmonary embolism (PE). Patients with PE and RHT are at an increased risk of poor outcomes compared to PE without RHT. Although the exact incidence of RHT is unknown, the increasing use of point‐of‐care ultrasound may lead to an increased detection and frequency of RHT. There are multiple treatment strategies available for RHT, including anticoagulation, systemic thrombolysis, and endovascular and surgical therapies. Given that these treatment strategies involve multiple medical specialties, the management of RHT with concomitant PE can be complex. Currently, there is limited clinical data and guidelines on the treatment and management of RHT. We aim to provide a review on RHT with concomitant PE, including risk stratification, treatment considerations, and our approach to the management of RHT.
Visibility, wind speed, and dew point temperature are important factors in SARS‐CoV‐2 transmissibility
Authors: Zhou Dansha , Wang Elizabeth W. , Hou Chi , Liao Jing , Zhang Jiarui , Fu Xin , Chen Jiyuan , Xing Yue , Hong Wei , Zhang Zhe , Chen Yuanwei , Feng Huazhuo , Chen Yilin , Yang Qifeng , Zhang Huosheng , Li Zicong , Feng Weici , Wang Ting , Lin Ziying , Zhang Chenting , Yang Kai , Lu Wenju , Wang Jian , Chen Yuqin
Published: April 2022

The aim of this study is to provide evidence for the influencing factors of severe acute respiratory syndrome coronavirus 2 (SARS‐COV‐2) virus mutation by determining the impact of geographical and meteorological factors on SARS‐CoV‐2 transmission, and the different impacts of SARS‐CoV‐2 variant strains. From January 20 to March 10, 2020, we collected a number of daily confirmed new cases and meteorological factors in all cities and regions in China and Italy affected by the Alpha “variants of concern” (VOC). We also collected the daily confirmed cases of the Delta VOC infection in China and Italy from May 21 to November 30, 2021. The relationships between daily meteorological data and daily verified new cases of SARS‐CoV‐2 transmission were then investigated using a general additive model (GAM) with a log link function and Poisson family. The results revealed that latitude was substantially connected with daily confirmed new instances of the Alpha VOC, while there was no such correlation with Delta VOC transmission. When visibility is greater than 7 m, the propagation of the Alpha and Delta VOCs in Italy and China can be controlled. Furthermore, greater temperatures and increased wind speed reduce the transmission of the Alpha and Delta VOCs. In conclusion, geographical and meteorological factors play an important role in SARS‐CoV‐2 transmissibility and should be considered in virus mitigation strategies.
The impact of the QBO on the region of the tropical tropopause in QBOi models: Present‐day simulations
Authors: Serva F. , Anstey J. A. , Bushell A. C. , Butchart N. , Cagnazzo C. , Gray L. J. , Kawatani Y. , Osprey S. M. , Richter J. H. , Simpson I. R.
Published: April 2022

The processes occurring in the tropical tropopause layer (TTL) are of great importance for stratosphere–troposphere exchanges and the variability of the Earth's climate. Previous studies demonstrated the increasing ability of atmospheric general circulation models (AGCMs) in simulating the TTL, depending on factors such as the horizontal and vertical resolution, with the major role for physical parametrizations. In this work we assess the mean state and variability of the tropical upper troposphere and lower stratosphere simulated by 13 AGCMs of the Stratosphere–troposphere Processes And their Role in Climate Quasi‐Biennial Oscillation initiative (QBOi) for the historical period. As these models internally generate quasi‐biennial oscillations (QBOs) of the stratospheric zonal wind, we can analyse the simulated QBO influence on the TTL on interannual time‐scales. We find that model biases in temperature near the tropopause are strongly related to water vapour concentrations in the lower stratosphere. A source of intermodel spread derives from stratospheric aerosols, as the responses to eruptions differ between those models prescribing volcanic aerosol forcing. The QBO influence on the thermal structure is generally realistic in the equatorial region, but the subtropical response is weak compared with the reanalysis. This is associated with a limited downward penetration of QBO winds, generally smaller QBO meridional widths, and weaker temperature anomalies, which disappear above the tropopause for most models. We discuss the QBO impacts on tropopause pressure and precipitation, characterized by large uncertainties due to the small signal in the observational records and sampling uncertainty. Realistic QBO connection with the troposphere in some models suggests that the underlying physical processes can be correctly simulated. Overall, we find that the QBOi models have limited ability to reproduce the observed modulation of the TTL processes, which is consistent with biases in the vertical and latitudinal extent of the simulated QBOs degrading this connection.
A geometric process with Hjorth marginal: Estimation, discrimination, and reliability data modeling
Authors: DEMİRCİ BİÇER Hayrinisa , BİÇER Cenker , BAKOUCH Hassan Salah Hassan
Published: April 2022

The geometric process is one of the important simple monotonic processes with a positive ratio parameter in the theory of stochastic processes. Simply, it can be thought of as a generalization of the renewal process (RP). In the current paper, we mainly study the geometric process with the Hjorth marginal distribution, with parameters θ and λ, for being able to model the successive inter‐arrival times with a trend. We first examine inference problem for the mentioned process from different perspectives and obtain the different estimators of its parameters by employing different estimation methods such as maximum likelihood, modified moments, modified maximum spacing, and modified least‐squares. The efficiencies of these estimators are compared via a series of extensive simulation studies in the paper. Further, we give also a discrimination statistic for discriminating among geometric processes with the Hjorth distribution and its alternatives. This is quite important to select the optimal geometric process model for data. Finally, a modeling study by using the geometric process with the Hjorth distribution is provided in detail to display its effectiveness to model the reliability data sets.
Unveiling the structure‐reactivity relationship involved in the reaction mechanism of the HCl‐catalyzed alkyl t‐butyl ethers thermal decomposition. A computational study
Authors: Cuesta Sebastián A. , Mora José R. , Meneses Lorena M. , Márquez Edgar A. , Flores‐Morales Virginia , Rincón Luis , Torres Fernando J. , Zambrano Cesar H.
Published: April 2022

The gas‐phase thermal decomposition of a series of alkyl t‐butyl ethers catalyzed by hydrogen chloride is theoretically studied at the ωB97XD/6‐311++g(d)//CCSD(T)/6‐311++g(d) level. The experimental activation free energy for three known systems namely: t‐butyl methyl ether, t‐butyl ethyl ether, and t‐butyl isopropyl ether is used for validation of the proposed theoretical model as the transition state (TS). The chemical process was characterized using intrinsic reaction coordinate, reaction force, and reaction electronic flux profiles. The Cαδ+Oδ− polarization was identified as the determining factor in the rate‐limiting step. Upon functionalization on the Cα, 24 new compounds with different electron‐withdrawing and donating groups were studied. A good multiple‐linear correlation (R2 = 0.88) was found between the Ln(kX/kH) as the response variable and the Taft‐Topsom substituent parameters as attributes. This result supports the reliability and predictability of the proposed transition state model at this level of theory.
Design and analysis of a wireless power transfer system for capsule robot using an optimised planar square spiral transmitting coil pair
Authors: Zhuang Haoyu , Wang Wei , Zhao Kai , Fei Qian , Yan Guozheng
Published: April 2022

Background

The wireless power transfer system (WPTS) is a promising way to continuously provide efficient and stable power for gastrointestinal capsule robots with active movement ability.

Methods

The proposed WPTS using an optimised planar square spiral transmitting coil pair with space‐saving structure can flexibly adjust the distance between the coils according to the patient's condition, and thus has better applicability. To improve power transfer efficiency and uniformity of the generated magnetic field, design parameters are discussed and optimised based on the analytical calculation and simulation analysis.

Results

The power demand can be guaranteed with spacing distance of 350–500 mm and the peak received power of 1124 mW with a remarkable transfer efficiency of 7.8% can be obtained when the spacing reaches the minimum. The human electromagnetic exposure safety in different situations is also discussed and verified.

Conclusions

The WPTS can provide power for capsule robots safely and efficiently.
Engineering Pollen‐Derived Microstructures to Reveal Material Morpho‐Performance Paradigm
Authors: Liu Dong , Zhang Ting , Cheng Xiaowen , Wang Bin , Guo Yijia , Liu Zhengzuo , Jiang Hao , Lu Yuan
Published: April 2022

The morphologies of micromaterials play a key role in their functionality and efficiency across a broad range of applications, including catalysis, environmental remediation, and drug delivery. However, the relationships between the morphologies and performances of micromaterials still need to be further understood, to guide the rational design of effective morphologies for specific applications. A pollen‐derived microstructure library containing multivariate morphological characterization and functional performance data is proposed and constructed here. Systematic multivariate correlation analysis is conducted to extract the key morphological factors influencing the photocatalytic and adsorption efficiencies, to reveal the morpho–performance relationships of pollen‐derived microstructures. Subsequently, a chrysanthemum‐derived microstructure is selected as a typical candidate; it features a unique morphology suitable for advanced photocatalysis and dynamic environmental remediation. To summarize, the construction of a pollen‐derived microstructure library offers a powerful tool for studying the morpho–performance relationships of micromaterials; this can provide significant guidance and inspiration for the rational design of micro/nanomaterials for numerous applications.
Facilitating Hot Electron Injection from Graphene to Semiconductor by Rectifying Contact for Vis–NIR‐Driven H2O2 Production
Authors: Hu Wei‐Yao , Li Qi‐Yuan , Zhai Guang‐Yao , Lin Yun‐Xiao , Li Dong , He Xiao‐Xiao , Lin Xiu , Xu Dong , Sun Lu‐Han , Zhang Shi‐Nan , Chen Jie‐Sheng , Li Xin‐Hao
Published: April 2022

Solar‐driven production of hydrogen peroxide (H2O2), as an important industrial chemical oxidant with an extensive range of applications, from oxygen reduction is a sustainable alternative to mainstream anthraquinone oxidation and direct hydrogenation of dioxygen methods. The efficiency of solar to hydrogen peroxide over semiconductor‐based photocatalysts is still largely limited by the narrow light absorption to visible light. Here, the authors proposed and demonstrate the proof‐of‐concept application of light‐generated hot electrons in a graphene/semiconductor (exemplified with widely used TiO2) dyad to largely extend visible light spectra up to 800 nm for efficient H2O2 production. The well‐designed graphene/semiconductor heterojunction has a rectifying interface with a zero barrier for the hot electron injection, largely boosting excited hot electrons with an average lifetime of ≈0.5 ps into charge carriers with a long fluorescent lifetime (4.0 ns) for subsequent H2O2 production. The optimized dyadic photocatalyst can provide an H2O2 yield of 0.67 mm g–1 h–1 under visible light irradiation (λ ≥ 400 nm), which is 20 times of the state‐of‐the‐art noble‐metal‐free titanium oxide‐based photocatalyst, and even achieves an H2O2 yield of 0.14 mm g–1 h–1 upon photoexcitation by near‐infrared‐region light (≈800 nm).
Nanocrystalline Cubic Silicon Carbide: A Route to Superhardness
Authors: Sun Rongxin , Wei Xudong , Hu Wentao , Ying Pan , Wu Yingju , Wang Linyan , Chen Shuai , Zhang Xiang , Ma Mengdong , Yu Dongli , Wang Lin , Gao Guoying , Xu Bo , Tian Yongjun
Published: April 2022

Superhard materials other than diamond and cubic boron nitride have been actively pursued in the past two decades. Cubic silicon carbide, i.e., β‐SiC, is a well‐known hard material with typical hardness <30 GPa. Although nanostructuring has been proven to be effective in enhancing materials’ hardness by virtue of the Hall–Petch effect, it remains a significant challenge to improve hardness of β‐SiC beyond the superhard threshold of 40 GPa. Here, the fabrication of nanocrystalline β‐SiC bulks is reported by sintering nanoparticles under high pressure and high temperature. These β‐SiC bulks are densely sintered with average grain sizes down to 10 nm depending on the sintering conditions, and the Vickers hardness increases with decreasing grain size following the Hall–Petch relation. Particularly, the bulk sintered under 25 GPa and 1400 °C shows an average grain size of 10 nm and an asymptotic Vickers hardness of 41.5 GPa. Boosting the hardness of β‐SiC over the superhard threshold signifies an important progress in superhard materials research. A broader family of superhard materials is in sight through successful implementation of nanostructuring in other hard materials such as BP.
LiBr–LiF‐Rich Solid–Electrolyte Interface Layer on Lithiophilic 3D Framework for Enhanced Lithium Metal Anode
Authors: Liu Ping , Su Han , Liu Yu , Zhong Yu , Xian Chunxiang , Zhang Yongqi , Wang Xiuli , Xia Xinhui , Tu Jiangping
Published: April 2022

Metallic lithium anode is considered as an ideal electrode for high‐energy‐density batteries. However, the uncontrollable growth of lithium dendrites, large volumetric change, and interfacial issues during the repeated plating and stripping processes severely hinder its practical applications. Herein, CoO nanosheets‐decorated sponge nickel are synthesized as a host skeleton for thermal‐injected Li (LCN). The conductive 3D matrix serves as a fast electron transfer path to decrease polarization and homogenize the local current density to suppress the Li dendrite. Moreover, the confined framework can relieve the volume change of lithium metal anodes. Furthermore, an artificial LiBr–LiF‐rich solid–electrolyte interface (SEI) layer is constructed at the surface of LCN by the in situ spray‐quenching method. Such an inorganic‐rich SEI provides fast longitudinal Li+ transportation and facilitates the uniform deposition of lithium. Accordingly, the SEI@Li/CoO@SN (SLCN) symmetrical cells exhibit a steady overpotential within 35 mV for 1700 h at 1 mA cm−2/1  cm−2 and achieve high Coulombic efficiency of 99.06% after 150 cycles. Matching with the sulfur cathode, the full cells present promoted rate performance and cycling stability and show a high initial capacity of 1274 mAh g−1 and good capacity retention.
Static mechanical properties of reactive powder concrete reinforced with basalt fibers
Authors: Sha Haiyang , Liu Jinchun
Published: April 2022

In this article, the effect of length (6, 12, and 18 mm) and volume fraction (0, 0.3%, 0.6%, 0.9%, 1.2%, and 1.5%) of basalt fibers (BFs) on the static mechanical properties of reactive powder concrete (RPC) was studied. The binding of BFs to matrix in BFRPC was investigated at the micro‐level by scanning electron microscope (SEM). The experimental results showed that BFs effectively improved the splitting tensile strength and flexural strength of the RPC, despite the effect of different lengths. With the increase in the BFs volume fraction, the splitting tensile strength and flexural strength first increased and then decreased. And, for compressive strength, 6 and 12 mm BFs can improve the strength, while 18 mm BFs caused strength recession. Compared with the experimental groups, it was found that the overall performance of RPC with the BFs length of 12 mm and the volume fraction of 0.9% was the best. The research results have great significance in the engineering application of BFRPC.
Methylmercury induced apoptosis of human neuroblastoma cells through the reactive oxygen species mediated caspase and poly ADP‐ribose polymerase/apoptosis‐inducing factor dependent pathways
Authors: Hou Shanshan , Zhang Xiayu , Ning Xiaofan , Wu Hao , Li Xinyue , Ma Kai , Hao Huifang , Lv Chunping , Li Chunrui , Du Zhongjun , Du Haiying , Jin Minghua
Published: April 2022

Methylmercury (MeHg) is an environmental neurotoxic substance, which can easily cross the blood–brain barrier, causing irreversible damage to the human central nervous system. Reactive oxygen species (ROS) are involved in various ways of intracellular physiological or pathological processes including neuronal apoptosis. This study attempted to explore the role of ROS‐mediated poly ADP‐ribose polymerase (PARP)/apoptosis‐inducing factor (AIF) apoptosis signaling pathway in the process of MeHg‐induced cell death of human neuroblastoma cells (SH‐SY5Y). Here, we found that SH‐SY5Y cells underwent apoptosis in response to MeHg, which was accompanied by the increased levels of ROS and calcium ion, and the activation of caspase cascades and PARP. Inhibiting the production of ROS can reduce the apoptosis rate to a certain extent. PARP/AIF apoptotic pathway is independent of caspase dependent signaling pathway and regulates it. In conclusion, these results suggest that ROS mediated activation of caspase pathway and PARP/AIF signaling pathway are involved in MeHg induced apoptosis, and these two pathways interact with each other.
Dirofilaria immitis prevention messaging: Knowledge and attitudes of students from North America attending the Ross University School of Veterinary Medicine, St Kitts
Authors: Jonk Kaitlyn , Mauldin Pereira Mary , Ketzis Jennifer , Conan Anne
Published: April 2022

Background

The expansion of vector‐borne diseases is considered to be a threat to pet health. Some diseases such as heartworm disease have effective individual prevention methods; however, population‐level disease control is limited by the lack of treatment compliance by pet owners. Veterinarians have a primary role in increasing compliance by educating owners on the appropriate prevention measures. Veterinary educational approaches targeting prevention strategies could strengthen prevention messaging at a clinic level.

Methods

A knowledge and attitude study was conducted with incoming Ross University School of Veterinary Medicine students as a preliminary assessment of this hypothesis.

Results

Seventy‐three students were interviewed using a tested and standardised questionnaire during their first weeks and 38 answered the same questionnaire one year later. All of the participants had previous experience in a veterinary clinical setting. Knowledge about the disease was variable, usually higher in former veterinary technicians. Unfortunately, knowledge of heartworm prevention was low. In addition, willingness to share knowledge on disease prevention did not change even after one year in veterinary school.

Discussion

These results suggest that additions within the veterinary and veterinary technician school curriculum may be required to improve knowledge about disease prevention and ultimately promote better communication with pet owners and veterinary clinical teams.
A hybrid process for leachate wastewater treatment: Evaporation and reverse osmosis/sequencing batch reactor
Authors: Bouchareb Raouf , Isik Zelal , Ozay Yasin , Karagunduz Ahmet , Keskinler Bulent , Dizge Nadir
Published: April 2022

In this study, a hybrid process for leachate wastewater treatment including evaporation and reverse osmosis (RO) membrane or biological treatment systems was suggested. Experiments were performed on a real landfill leachate wastewater. The leachate was subjected to evaporation; as a result, a distillate was obtained containing less organic matter and less substantial amounts of other pollutants, as ammonium salts and total phenols were removed. Tests were carried out at different evaporation temperatures and times. The initial leachate pH was adjusted and optimized. For optimum conditions, each of chemical oxygen demand (COD), total phenol, and ammonium salt concentrations were reduced to 99.99%, 95.00%, and 83.00%, respectively. The distillate of the first stage of the proposed process was then exposed to RO membrane system, as a first study, under different transmembrane pressure of 20, 30, and 40 bar and at different pH values of 7, 8, and 9. As a second suggested treatment system, the distillate was subjected to a biological treatment process for 30 days as a retention time, pH = 6, and room temperature 25°C ± 1°C. At the end of the research study, a comparison was conducted between results obtained with RO membrane separation and biological treatment system as two distinct treatment systems proposed for leachate landfill wastewater treatment. Although both systems were effective for landfill leachate wastewater treatment, however, with the RO membrane separation system, COD removal efficiency reached 99.99%. In the other hand, with biological treatment process, COD elimination was as much as 90.00%. Certainly, evaporation and RO are not novel ways of landfill leachate treatment; however, few studies have attempted to use similar combined system for landfill leachate wastewater treatment and attained effective results of treated water.

Practitioner Points

A hybrid process of evaporation and RO membrane or biological treatment systems was suggested for leachate wastewater treatment.

For optimum conditions, COD, total phenols, and ammonium salt reductions were achieved to 99.99%, 95%, and 83%, respectively, after the first evaporation stage.

The distillate of the first stage of the proposed process was then exposed to RO membrane system and biological treatment system.

Different transmembrane pressure and different pH values were optimized for RO.