bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing human coronavirus OC43 growth and titration
Authors: Savoie Christopher , Lippé Roger
Published: July 2022

Coronaviruses have been at the forefront of the news for the last 2 years. Unfortunately, SARS-CoV-2, the etiologic agent for the COVID-19 pandemic, must be manipulated in biosecurity level 3 settings, which significantly limits research. Meanwhile, several less pathogenic human coronaviruses (HCoV) exist and can be studied in much more common biosafety level 2 laboratories. Among them, HCoV-OC43 is a good surrogate candidate for SARS-CoV-2 since both are phylogenetically related human Betacoronaviruses. However, one issue has been the lack of standardized means among laboratories to propagate and titer this less virulent coronavirus. The present study probes the optimal parameters to propagate HCoV-OC43. First, testing of five different cell lines (MRC-5, Huh7.5, Vero, HCT-8, HRT-18) indicated that the physiologically relevant MRC-5 human lung cell line produced among the highest viral titers. HRT-18 may however be an interesting alternative as they are quick growing cells that also led to higher viral titers and a better tropism for various HCoV-OC43 variants. We also probed the impact of serum and temperature during viral expansion and confirmed that the normal temperature of the upper respiratory track (33 °C) improves viral yields over the typical 37 °C used to grow many other viruses. Meanwhile, we did not notice any evidence that serum concentrations significantly affected the virus but interestingly noted that the virus grew quite efficiently in a serum-free media formulation. Meanwhile sonication of viral stocks somewhat improved viral titers. Four titration methods (plaque assays, TCID50-CPE, TCID50-IFA and TCID50–IPA) were also probed using two cell lines (VeroE6 and HRT-18). In our hands, plaque assays proved unreliable and quantification of the virus by scoring CPE positive wells was significantly less sensitive than antibody-based assays (IFA and IPA). While the latter methods were equally sensitive, we favor the TCID50-IPA method since simpler, faster and cheaper than the IFA protocol. Moreover, the HRT-18 cells appeared more sensitive to quantify the virus. Perhaps most importantly, these optimized protocols routinely led to high titer viral stocks in the order of 108 TCID50/ml magnitude, which should fulfill the requirements of most experimental settings.
Clinico-pathological and Genomic Characteristics among Children with SARS-CoV-2 Infection
Authors: Gupta Vivek , Scaria Vinod , Srivastava Anurag , Raja Akash , Kalhan Shivani
Published: July 2022

Introduction: There is inadequate information on infections with the Severe Acute Respiratory Syndrome Virus 2 (SARS-CoV-2) in children. Their clinical, as well as pathological correlation, is poorly understood. In India, children and adolescents account for 12% of all Coronavirus Disease 2019 (COVID-19) cases reported. Children accounted for roughly 11% of those impacted globally last year. However, this year, we are seeing around 20- 40% of youngsters in positive instances over the world. Even babies and infants are testing positive for COVID-19, although their illness is under control and seldom becomes fatal. Children aged 5 to 12 years, on the other hand, are at a higher risk. Aim: To study the clinical, pathological and genomic characteristics among children with SARS-CoV-2 infection. Materials and Methods: This cross-sectional study was conducted among 48 paediatric positive patients for SARSCoV-2 at Government Institute of Medical Sciences, Noida, Uttar Pradesh, and CSIR-Institute of Genomics and Integrative Biology, New Delhi, India, from 2021 and May 2021. The laboratory testing was done by the real-time Reverse Transcription-Polymerase Chain Reaction (RT-PCR) method. The patients were classified as mild, moderate, severe, or asymptomatic. Their clinical and pathological findings were recorded in the case sheet. Genomic analyses were done for identifying the genetic variant in the nine selected samples. Data entry and analysis were performed using Statistical Package for Social Sciences (SPSS) version 26.0. Chi-square test was used for categorical variables and the t-test was used for continuous variables. Results: The study group has median age of 12 years. Male:Female ratio was 2:3. Most children had acquired infection from the community and 30% had the moderate illness and were admitted. Serum Glutamic-Oxalacetic Transaminase (SGOT) and Glutamic-Pyruvic Transaminase (SGPT) were raised in six patients. Alkaline Phosphatase (ALP) was raised in 21 patients and bilirubin was raised in two patients. The average duration of hospitalization was 6 days (range 2-13 days). No mortality among the 48 paediatric patients studied was identified in the hospital. Delta variant (B.1.617.2) was identified in seven patients with D614, P681R, L452R mutations and B.1.617.2 was identified in two patients. Delta variant was present in the paediatric patients but it did not prolong the hospital stay or cause mortality. Conclusion: The findings of the study suggest that children may be a potential source of infection in the SARS CoV2 pandemic while having an asymptomatic to mild illness.
Antibiogram Pattern of Bacteria Isolates from Ground Water (Borehole Water) Resources in Port Harcourt, Southern Nigeria
Authors: Eddeh-Adjugah O. G. , Ogbonna D. N. , Ngah S. A. , Youdeowei P. O.
Published: July 2022

The study considered antibiogram of bacteria isolates from selected ground water (borehole water) resources susceptibility pattern of the isolated microorganisms in Port Harcourt during the dry and wet season of 2020. Seven (7) sampling locations designated as Abuloma, Borikiri, Eagle Island, Fimie, Macoba-Isaka, Rumuekini and Rumuokoro in Port Harcourt Metropolis were established. Water samples were collected from boreholes in 10 ml sterile sampler and placed in an ice-parked container and send to the laboratory for the analysis of Vibrio, Stapylococcus, Total Heterotrophic bacteria, Salmonella, Shigella, Total coliform and Fecal coliforms). Bacteria isolates were examined for the susceptibility and resistance of Ofloxacin, Augumentin, Cetazidine, Gentamycin, Cefiximine, Ciproflaxin, Cefturoxine and Nitrofurantoin. There were observed increased rate of resistance antibiotics in this study which could be attributed to the widespread misuse of various antibiotics without control. The E. coli percentage resistance isolates from the water sources discovered that Ofloxacin, Ciproflaxin, Nitrofurantoin had no value in percentage resistance of the E coli isolated. Augmentin had 50% (Abuloma), 100% (Rumuokoro, Rumuekini, Makoba-Island and Eagle Island). Ceftazidime had 100% (Borikiri, Fimie, Abuloma, Rumuokoro, Rumuekini, Makoba-Island and Eagle Island) correspondingly. Gentamicin had 50% (Abuloma), 60% (Rumuekini), 100% (Rumuokoro, Makoba-Island and Eagle Island). Cefixime had 100% (Borikiri, Fimie, Abuloma, Rumuokoro, Rumuekini, Makoba-Island and Eagle Island) while Cefuroxim had 100% for (Borikiri, Fimie, Abuloma, Rumuokoro, Rumuekini, Makoba-Island and Eagle Island). The susceptibility in percentage of the E coli isolated revealed that Ofloxacin had percentage value of 100% (Fimie, Rumuokoro, Rumuoekini, Abuloma, Makoba-Isaka, Eagle Island and Borikiri) respectively. Augmentin and Gentamicin had 50% in Abuloma. There was no percentage value for Cetazidime, Cefixime and Cefuroxime while Ciproflaxin appeared as 100% (Fimie and Borikiri) and 50% (Rumuokoro and Abuloma) respectively. Nitrofurantoin had percentage values as 100% in Abuloma, Borikiri, Eagle Island, Fimie, Makoba-Isaka, Rumuekini and Rumuokoro correspondingly. Findings holds that the microbial counts of groundwater resources are moderately lower, intense commercial activities increase the rate of occurrence of microbial activities in water bodies, the high percentage resistance is a factor of indiscriminate waste disposal pattern and drug abuse of the citizenry. Thus, it is recommended that groundwater source (boreholes) be sited away from septic tanks source(s) as possible interference under the influence of proximity could become inevitable. More so, public health education on the dangers of drug abuse and indiscriminate waste disposal be encouraged.
Status of Water Quality from Agriculture Drains in Guntur District, Andhra Pradesh, India
Authors: Tejaswini Vallu , Babu G. Ravi , Kumar H. V. Hema , Prasad B. V. S. , Rao Ch. Sujani
Published: July 2022

Quality of agriculture drain water was assessed from selected locations in Guntur district, Andhra Pradesh, India. Waste water samples collected from agriculture drains were analysed for quality parameters such as pH, electrical conductivity, total dissolved solids, total hardness, chlorides, carbonates, bicarbonates, calcium, magnesium, sulphates, phosphates, sodium, potassium, ammonical nitrogen, nitrates nitrogen, dissolved oxygen and chemical oxygen demand. Piper diagram, water quality indices such as sodium adsorption ratio, percent sodium, residual sodium carbonate, magnesium ratio, permeability index and potential salinity were used to assess the suitability of drain water for irrigation. The EC values of water samples ranged from 0.57-5.01 dS/m with an average value of 1.27 dS/m. Water of 16 agriculture drains were found to be unsuitable for irrigation with regard to percent sodium (%Na) and 6 drains with regard to potential salinity.
Generating Synthetic Monthly Net Radiation Data Conditioned on Wind Speed
Authors: Ojochenemi Agada, Inikpi , Terver Sombo , Utah Utah Effiong
Published: July 2022

Aims: This study aimed at generating synthetic monthly net radiation data conditioned on wind speed over Port Harcourt, Benue, Kano and Enugu in Nigeria.

Duration of Study: The daily maximum and minimum Relative-Humidity, maximum and minimum air temperature, solar radiation and wind speed data was obtained from the International Institute of Tropical Agriculture (IITA) Ibadan, Nigeria for the period of thirty-four (34) years (1977-2010).

Method: The Penman-Monteith (FAO-56) step by step method was used to compute the daily net radiation. The autocorrelation function was used to establish the fact that net radiation and wind speed exhibit the Markov property. Lastly, a two – state Markov Chain model and an indicator function of energy balance and imbalance was developed and used in the course of this work.

Results: The finding reveals that net radiation is surplus over the study areas. The Lag one autocorrelation coefficient confirms the fact that an actual day net radiation and wind speed state depends on the previous day’s state. The monthly steady state probabilities of surplus net radiation conditioned on low wind speed is higher compared to monthly steady state probabilities of surplus net radiation conditioned on high wind speed. The indicator function of energy balance or imbalance reveals that there is energy imbalance over study areas.

Conclusion: The generated synthetic net radiation data conditioned on wind speed preserved the characteristics of actual net radiation data when compared as observed in the study. This data is essential in the study of climate change, weather monitoring, agricultural meteorology and estimation of evapotranspiration.
Impact of Precipitation over the Productivity of Sugarcane in Major Agro-climatic Zones of Tamil Nadu
Authors: Kumar P. Dinesh , Biswas Tufleuddin
Published: July 2022

Sugarcane is one of the traditional crops grown abundantly across the state of Tamil Nadu due to the lengthening of the period of monsoon and its diversified uses in different agro-based industries. Precipitation, a significant factor for sugarcane cultivation, has an impact on its productivity differs for different agro-climatic zones. A secondary data of district wise precipitation and sugarcane productivity of Tamil Nadu for the 30 years (1985 - 2014) were also collected. The impact of precipitation over the productivity of various crops can be explained by using the Standard Precipitation Indices (SPI) data and applying Principal Component regression (PCR) technique. Initially, SPI, A drought monitoring index, represents a Z-Score, was calculated seasonally for different agro-climatic zones. As there was a severe collinearity between the SPI values of seasons, Principal component regression analysis was used to study the impact of precipitation on the sugarcane productivity by considering the SPI values of four seasons along with time as regressor variables. The study showed that the productivity of sugarcane in Cauvery Delta zone and Western Zone mainly depended upon the precipitation during South west monsoon and North East monsoon periods. However, the productivity of sugarcane in North East zone was mostly dependent on the precipitation of Cold Weather period when compared to all other seasons. Unlikely, North west and Southern zones are not significantly influenced by the precipitation.
Evaluation of the Potential of Smart Fertilizers on Growth and Nutrient Availability of Wheat (Triticum aestivum L.)
Authors: Verma Shikhar , Rana N. S. , Vivek . , Rastogi Mausmi , Singh Bal Veer , Yadav Praveen Kumar , Mohapatra Sweekruta
Published: July 2022

A field experiment was conducted at crop research centre of SVPUA&T, Meerut (U.P.) India during 2020-21. Novel nutrient sources and their modes of applications with 12 treatments consisting of Control, NPK-(150:60:40 q ha-1), 100 % NPK + Nano Zn spray, 100 % NPK + Bio-stimulant spray, 75 % NPK + NPK Consortia, 75 % NPK + NPK spray, 75 % NPK + NPK Consortia + Nano N spray, 75 % NPK + NPK Consortia + NPK spray, 75 % NPK + NPK Consortia + NPK spray +Bio-stimulant spray, 75 % NPK + NPK Consortia + NPK spray + Bio-stimulant spray + Nano Zn spray, 75 % NPK + NPK Consortia + Nano Zn spray, 75 % NPK + NPK Consortia + Nano N spray + Nano Zn spray were attempted on wheat variety HD 2967 in  randomized complete block design (RCBD) with three replications. The application of 75 % NPK + NPK Consortia + NPK spray + Bio-stimulant spray + Nano Zn spray was found at par with 100 % NPK nano Zn / Bio-stimulant and significant over recommended dose of fertilizer (RDF) with a better growth attribute and yield ie. plant population (307.8 no. m-2), plant height (110.6 cm), number of tillers m-1 row length (68.9), dry matter accumulation (294.0 g m-1) and grain yield (55.9 q ha-1 ) with a better availability of nutrients in soil.
Effect of Gibberellic Acid and Naphthalene Acetic Acid on Growth and Yield of Cucumber (Cucumis sativus L.) in Prayagraj Agro Climatic Conditions
Authors: Thejaswi Paluru , Deepanshu . , Bahadur Vijay
Published: July 2022

The experiment was conducted to determine the effect of gibberellic acid and Naphthalene acetic acid on growth and yield of cucumber at Horticulture Research Field, Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj during mid March- mid June 2021. Total Nine treatments were tried and replicated three times in a Randomized Block Design. Treatments include two growth regulators having concentrations of GA3 (15, 25, 35, 45 ppm) and NAA (75, 100, 125, 150 ppm) and Control (Water spray) were spayed at two leaf stage and four-leaf stages. The application of plant growth regulators significantly effects the vegetative as well as reproductive attributes of the crop. The treatment T3 25 ppm GA3 at 2, 4 leaf stage was found most effective among all the treatments in terms of Vine length at 20, 40, 60 days after sowing (39.12, 91.02, 180.32 cm) Days to first appearance of male flowers in 50% plants (32.86 days), Number of fruits per plant (12.20), Average fruit yield per plant (1870.37 g), fruit weight (153.33g) where as Days to first appearance of female flowers in 50% plants (38.93) and Days to first harvest (50.6) was observed in 35 ppm GA3, length of the fruit (14.66 cm in 15 ppm GA3), fruit diameter (4.28 cm in 15 ppm GA3), Average yield (18.77 t/ha in 25 ppm GA3). Based on these observations spraying of GA3 25 ppm at 2, 4 leaf stages was found effective for growth and yield of cucumber compared to other concentrations of GA3, NAA and control.
Effect of Some Processing and Storage Methods on the Quality of Okra (Abelmoschus esculentus)
Authors: Kafui Jarh Alexander , Asiedu Samuel Yeboah , Drafor Simon , Tekpor Samuel Kofi
Published: July 2022

Three experiments, comprisin packaging of fresh Okra for storage, dipping of fresh fruits in hot water before  packaging  to store  and drying of sliced Okra fruits, were carried out in the laboratory at the Department of Horticulture, Kwame Nkrumah University of Science and Technology. The objective of the study was to assess the effect of some processing and storage methods on the quality of okra. The experimental design used for the storage work was Completely Randomized Design (CRD). There were 10 treatments for the experiment.  A portion of plot measuring 14m x 40.5m was demarcated for planting and drying was done by using a solar cabinet dryer located at the old site of Forestry Research Institute of Ghana, located on the compound of the Kwame Nkrumah University of Science and Technology. Results from the first experiment which involved packing and storing of fresh okra fruits indicated that, Fresh okra fruit packed in both polypropylene and polyethylene bags  and store at 7- 9 C can stay up to 24 days  with no significant (p ≤  0.05) weight lost. However produce packed in perforated polypropylene and polyethylene bags gave a higher salvage of 82.1% compared to 77% from those packed in the imperforated bags of the two packaging materials. The second experiment which involved hot water treatment of okra fruit before packaging for storage indicated a very fast rate of deterioration of fruits, with no fruit being salvaged at the end of the storage period. The third experiment involving slicing and drying of okra fruits in a solar cabinet dryer indicated that samples from both stages of maturity dried for 24hours lost comparatively less weight than those dried for 48hours. This shows that the longer the drying period, the more the lost in weight. From the three experiments it was concluded that packaging and storage of fresh okra fruit enables the fruit to keep longer and remained in the useable state than unpacked storage. Harvesting fruit at 4 and 6days, after setting for storage is appropriate, however those harvested at 6days after setting will come out with greater number of unusable fruit after the storage period. On the choice of packaging material one should prefer polypropylene to polyethylene for bitter results. Also perforation of the chosen material had advantages over the imperforated ones. Hot water treatment of okra fruits can be applied under situations where the fruits may be used within 16 days or less but not longer.
Prevalence and Antimicrobial Susceptibility of Salmonella spp Isolated from Ready-to-eat foods and Food Handlers in Port Harcourt Metropolis, Nigeria
Authors: F. Ndu, Ijeoma , O. Ollor, Amba , G. Nwokah, Easter , K. Wachukwu, Confidence
Published: July 2022

Aim: To assess the prevalence and antimicrobial susceptibility of Salmonella species isolated from ready-to-eat foods and food handlers in Port Harcourt Metropolis, Nigeria.

Study Design:  Cross-sectional study

Place and Duration of Study: This study was conducted in selected places in Port Harcourt, between November 2019 and June 2021.

Methodology: A total of 350 food specimens and 230 food handlers’ specimens were collected. The following street vended food were analysed: White rice/stew, Jollof rice, Rice/beans stew, Porridge beans, Beans/stew, Moi Moi, Africa salad and Roasted plantain. The social demographic information was collected using a questionnaire survey. The samples were analysed for contamination with Salmonella species using conventional protocol. Salmonella species were isolated from samples using Salmonella-Shigella agar (SSA), Xylose-lysine desoxycholate agar (XLD), MacConkey agar (MA), Blood agar (BA) after pre-enrichment and enrichment method has been done using peptone water broth and selenite F broth. Salmonella Chromogenic medium (SCM) was also used to confirm the isolate. Antibiotic susceptibility patterns of the Salmonella isolates were determined using Kirby Bauer disk diffusion method. Data collected was analyzed with the Statistical Package for Social Sciences (SPSS, V25, IBM, USA). The prevalence and distribution of Salmonella sp and antibiotic resistance patterns were presented in frequencies and percentages. All analysis was done at a 95% confidence interval and p-values less than 0.05 were considered significant.

Results: The prevalence of Salmonella species in the street vended foods was 8.2% and 4.8% among the food handlers. However, there was no statistically significant difference in the proportion of Salmonella growth observed in street vended food and food handlers (P= 0.2900). The isolates from street vended foods and handlers were susceptible to Sulfamethioxazole/Trimetoprin and Meropeneme and resistant to Amoxiclave, Ceftiaxone, Ampicillin, Cefotaxime, Ceftazidine, Levofloxacin and Tetracycline. 

Conclusion: Salmonella isolates identified from the samples and their handlers showed susceptibility to ciprofloxacin, erythromycin, gentamicin, meropenem, sulfamethroxazole/ Trimethoprim with more isolates being sensitive to meropenem. However, they were resistant to amoxiclav, ceftazidine, cefotaxime, levofloxacin and ceftriaxone.
The Effect of Employee Training on Organizational Commitment and Turnover Intention: A Mediating Role of Job Satisfaction
Authors: Astuti Rini Juni , Harnuansa Hukas Amartya
Published: July 2022

Aims: This study aims to analyze the effect of   Employee training on Organizational Commitment and Turnover Intention with Job Satisfaction as Mediation.

Study design: Hypotheses Testing.

Place and Duration of Study: 111 employees at Banjar Hospital, Indonesia.

 Methodology: Structural Equation Modeling (SEM) based on AMOS.

Results: First, employee training positively effects on organizational commitment at the Banjar Hospital. Second, employee training positively effects on job satisfaction. Third, job satisfaction positively effects on organizational commitment. Fourth, job satisfaction mediates on the effects employee training on organizational commitment at the Banjar Hospital. Fifth, the findings further show that job satisfaction does not effects on turnover intention at the Banjar Hospital. Finnaly, employee training does not effects on turnover intention at the Banjar Hospital.

Conclusion: Employee Training and job satisfaction effect on organizational commitment.  Employee training effects on job satisfaction. Job satisfaction has a significant as mediator between  employee training and  organizational commitment. Meanwhile, Job satisfaction and employee training do not effect on turnover intention.
Analyze and Compare the Pain Level and Complications of Septoplasty with and without Splints and Packing
Authors: Rajput Muhammad Iqbal , Mahar Gulam Shabir , Ansari Noor Alam , Khaskhili Muhammad Saleh , Irfan Rao , Meraj Munazzah
Published: July 2022

Aim: The main objective of this study is to analyze and compare the pain level and complications of septoplasty with and without splints and packing.

Methodology: Our study comprised of 100 patients who underwent septoplasty procedure both under general and local anesthesia. They were divided into two groups. One group of 50 patient had splints and packing while the other group of 50 patients had no splints and packing post operatively. Patients were chosen randomly. Children and elderly patients were excluded from the study. Printed proforma was used to compare the result in terms of pain scores and complications. Regular follow-up was done for average six months. The study was approved by ethical review board PUMHSW Nawabshah.

Results: Pain scores were higher in patients with splints and packing both in post-operative period and at the time of removal of splints and packing. There was no significant difference regarding other post operative complications.

Conclusion: It is concluded that pain and discomfort associated with nasal splints and packing does not justify their application in case of certain minor to moderate nasal septal defects undergoing surgery. However when septal surgery is extensive and associated turbinate and framework procedure are done, splints and packing become mandatory in our setup.
Elucidating the Multi‐Scale Temperature Evolution and Densification Mechanisms of Amorphous Powders During Spark Plasma Sintering: Experiments and Modeling
Authors: Ding Huaping , Bao Xiaoqian , Zhang Mao , Tang Xuefeng , Niu Yong , Gong Pan , Wang Xinyun
Published: July 2022

This work investigates amorphous powders’ temperature distribution and densification mechanism at macroscopic and particle scales during spark plasma sintering. The evolution of contact necks between powders is studied by quasi‐in situ microstructure examination. Amorphous powders’ contact mode changes from point contact to surface contact as sintering proceeds. The high current density concentration leads to local overheating at the particle necks. As the contact radius ratio increases, the temperature gap between the necks and the interior of the particles becomes less noticeable. In the early stage, localized high temperature and high stress around the necks significantly reduce the densification onset temperature of amorphous powders. As the relative density increases, the uneven temperature field at the particle scale disappears, while the macroscopic temperature gradient increases. The dominant densification mechanism of amorphous powders has transitioned from particle‐scale to macroscopic temperature. The sample temperature is significantly higher than the nominal sintering temperature, promoting the contribution of viscous flow to porosity elimination. This work can provide new insights into the evolution of multi‐scale temperature distribution during spark plasma sintering and its impact on the densification behavior of amorphous powders.
Evolution of Stacking Fault and Dislocation during Dynamic Recrystallization of Inconel 625 Alloy
Authors: Wang Yanjiang , Jia Zhi , Ji Jinjin , Li Sidan , Liu Dexue
Published: July 2022

The purpose herein is to improve the understanding of microstructure evolution of inconel 625 alloy during the dynamic recrystallization (DRX) process. Herein, the evolution process of DRX is determined by the grain orientation spread (GOS) method, and 1100 °C is determined as the complete recrystallization temperature. Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) techniques are used to investigate the density and morphology of dislocations and stacking faults (SFs), as well as the effects of dislocations and SFs during recrystallization. With increasing recrystallization fraction, the density of dislocations and SFs decreases gradually, the dislocation start is extended, and SFs appear on other crystal planes. The existence of dislocation and SF increases the nucleation energy and nucleation sites of recrystallization, respectively, which is beneficial to the nucleation of DRX.
Quantitative Evaluation of Loss Capability for In Situ Conductive Phase Enhanced Microwave Absorption of High‐Entropy Transition Metal Oxides
Authors: Dai Guohao , Deng Ruixiang , Zhang Tao , Yu Yun , Song Lixin
Published: July 2022

High‐entropy oxides (HEO) with high stability and designability are potential microwave absorbers that serve in harsh environments. However, loss design is critical for the absorption performance of HEO due to its weak intrinsic loss capability. Inadequate loss ability results in considerable secondary reflection. Here, an in situ conductive heterogeneous phase is constructed in (Fe0.2xCo0.2Ni0.2Cr0.2Mn0.2)3O4 (x = 1–5) using a reductive circumstance, to form a dual‐phase composite. Both the ohmic and dielectric loss are enhanced as the conductive phase is introduced, while great impedance matching condition is well maintained. Hence, the composites can achieve substantial absorption across the whole X or Ku band with a thin thickness. Furthermore, key efforts are made to reveal the relationship between the absorbing performance and loss capability of an absorber. The analytical expression of the theoretical threshold of attenuation constant is derived. Based on the statistics of experimental data, the broad feasibility and practicability of the proposed theoretical threshold of attenuation constant are confirmed and discussed. Combined with both the theoretical and experimental studies, the mechanism by which the conductive phase contributes to increased absorption is also disclosed, providing an effective basis for the loss design of broadband microwave absorbers.
Strongly Coupled Interfacial Engineering Inspired by Robotic Arms Enable High‐Performance Sodium‐Ion Capacitors
Authors: Song Zirui , Zhang Guiyu , Deng Xinglan , Tian Ye , Xiao Xuhuan , Deng Wentao , Hou Hongshuai , Zou Guoqiang , Ji Xiaobo
Published: July 2022

Interfacial coupling strategy has allured extensive attention for the possibility to endow active electrode materials with superior performance. However, the design of strong coupling engineering with interfacial evolution during electrochemical processes is very challenging. Herein, inspired by the powerful robotic arms and density functional theory calculations, multiple functional groups identified with intense affinity to V atom are successfully grafted on carbon nanotubes (CNTs), thereby in situ building robust interfacial bonds (VOC and VC) to tightly anchor VS4 particles. The largely decreased band gaps and energy barriers show the fortified conductivity of VS4‐CNT heterostructure. Besides, the spacial confinement effect induced by interfacial linkages substantively enhances the mechanical properties to inhibit structural collapse, and restrains the dissolution of polysulfides as verified by molecular dynamics simulations, thus prolonging life span. Excellent energy density of 105.5 Wh kg–1 can be delivered after assembling full sodium‐ion capacitors (activated carbon//VS4‐CNT). Significantly, the reversible interfacial bonds confirmed by various ex situ characteristics during discharge/charge processes hold the key to remarkable sodium storage ability and prominent initial coulombic efficiency. More impressively, strong interfacial coupling effect can establish synergistic soft‐rigid integrated solid‐electrolyte interphase film, which is conducive to elevating the electrochemical performance of electrodes, convincingly constructing advanced sodium‐ion capacitors.
Superior Electrocatalyst for All‐pH Hydrogen Evolution Reaction: Heterogeneous Rh/N and S Co‐Doped Carbon Yolk–Shell Nanospheres
Authors: Bu Xiuming , Bu Yu , Quan Quan , Yang Siwei , Meng You , Chen Dong , Lai Zhengxun , Xie Pengshan , Yin Di , Li Dengji , Wang Xianying , Lu Jian , Ho Johnny C.
Published: July 2022

Design of efficient and robust electrocatalysts for hydrogen evolution reaction (HER) under all pH conditions has attracted significant attention. In particular, it is still a considerable challenge since the HER kinetics of Pt in alkaline solutions is about two to three orders of magnitude lower than that in acidic conditions. Herein, a heterogeneous yolk–shell nanostructure with Rh nanoparticles embedded in S, N co‐doped carbon nanospheres prepared by a facile self‐template method is reported. The optimized electrocatalyst can achieve an extremely small overpotential of 13.5 mV at 10 mA cm‐2, low Tafel slope of 25.5 mV dec‐1, high turnover frequency of 0.143 s‐1 (at −75 mV vs. reversible hydrogen electrode), and long‐term durability for 10 h, which is the record‐high alkaline HER activity among the ever‐reported noble metal based catalysts. These striking performances are ascribed to the optimized electronic structure and unique heterogeneous yolk–shell nanostructure. More importantly, it is also demonstrated that the obtained electrocatalyst exhibits superior activities in all pH range, which is better than commercial Pt/C and Rh/C catalysts. This work proves that Rh‐based nanomaterials are promising superior electrocatalysts in a wide pH range and nanostructure design is a powerful tool to increase the mass/electron transfer during reaction.
Flexible Sensor Based on Fe3O4‐COOH@Ti3C2Tx MXene Rapid‐Gelating Hydrogel for Human Motion Monitoring
Authors: Hu Yongqin , Hou Chen , Du Jihe , Fan Qianxi , Fang Junan , Shi Yuxia , Yang Guanghao , An Jia , Liu Yufei
Published: July 2022

Although hydrogels are still in their infancy, research is primarily focused on optimizing their mechanical, antibacterial, anti‐frost, and water‐retaining properties. However, the rapid preparation of hydrogels without external energy stimulation remains a significant challenge. In this study, a Fe3O4‐COOH@MXene@silk fibroin@polyacrylamide hybrid hydrogel (FM@SF‐PAAM) is successfully fabricated using an innovative rapid gelation method, which can initiate the gelation process as low as 7 s and formed at an extremely rapid rate at room temperature, without the use of external energy. The as‐obtained FM@SF‐PAAM hybrid hydrogel exhibits excellent electrical conductivity (6.44 × 10–2 S m–1) and mechanical properties, with a maximum strain of 1660%. Additionally, the FM@SF‐PAAM‐based flexible strain sensor can monitor joint movement and emotional changes, such as finger and elbow bending, glaring, smiling, and mouth opening. Thus, the radical polymerization process demonstrates the immense potential for application to nearly all types of MXene‐based hydrogels and is likely to serve as a foundation for the development of flexible hydrogel‐based devices.
Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO
Authors: Lee Joon Yup , Kim Eun A , Han Jisu , Choi Yeong‐Ho , Hahm Donghyo , Kang Chi Jung , Bae Wan Ki , Lim Jaehoon , Cho Seong‐Yong
Published: July 2022

Colloidal quantum dot‐based light‐emitting diodes (QD‐LEDs) are one of the potential future self‐emissive displays owing to their large‐scale solution‐processibility and high color purity. For the industrial application of QD‐LEDs, high‐performance QD‐LED and high‐resolution patterning of quantum dot (QD) films are required. Photolithography is an ideal tool for patterning QD films. Previously, the high‐resolution patterning of QD films using direct photolithography by ultra‐thin atomic layer deposition of ZnO on the QD surface is reported. The patterning process is acceptable for Cd‐based QD films, but the photoresist severely deteriorates the photoluminescence (PL) intensity of InP‐based QD films owing to the presence of sulfonic groups in the photoactive compound. Herein, a non‐destructive direct photolithography process for QD film patterning using a negative photoresist that does not affect the PL intensities of Cd‐ and InP‐based QD films is reported. The effect of the photoresist is also verified by a PL lifetime study. Extremely bright Cd‐ and InP‐based QD films are successfully patterned using a softer photoresist, and micropatterning of InP‐based QD films is reported for the first time in this work using photolithography. A QD electroluminescence device is also successfully fabricated using the patterning method.
Dual‐Quasi Bound States in the Continuum Enabled Plasmonic Metasurfaces
Authors: Zhou Yi , Guo Zhihe , Zhao Xuyang , Wang Feilong , Yu Zhiyuan , Chen Yizhen , Liu Zhiran , Zhang Shuyu , Sun Shulin , Wu Xiang
Published: July 2022

Localized surface plasmon resonances (LSPRs) in metallic nanostructures attract great attention for their potential applications such as highly sensitive optical sensors. However, the performance of LSPR sensors is strongly hampered by their low quality (Q) factors due to the intrinsic ohmic losses and far‐field radiation losses. Here, a kind of all‐metal metasurfaces that can achieve high‐Q and high figure of merit (FOM) resonances based on bound states in the continuum (BICs), is theoretically designed and experimentally demonstrated. The devices can simultaneously exhibit symmetry‐protected and Friedrich–Wintgen quasi‐BICs features at normal incidence, leading to higher Q‐factors than those solely inspired by single quasi‐BIC. Additionally, the constraint of symmetrical dielectric environment for common metasurfaces can be released by utilizing a metal substrate rather than a dielectric one. The proof‐of‐concept experiments demonstrate the high performances of such dual quasi‐BIC based plasmonic refractive index sensors with the Q‐factor of 145, the sensitivity of 657 nm RIU‐1, and the FOM of 109 RIU‐1. These findings may stimulate some promising applications, such as biosensing, optical lasing, and light absorption.
Few‐layered MoS2 Based Vertical van der Waals p‐n Homojunction by Highly‐efficient N2 Plasma Implantation
Authors: Shan Yufeng , Yin Ziwei , Zhu Jiaqi , Li Xin , Dou Wei , Wang Yue , Liu Chixian , Deng Huiyong , Dai Ning
Published: July 2022

2D transition metal dichalcogenides have shown great potential for next‐generation microelectronic devices owing to their ability to prolong the life of Moore's law by mitigating the short‐channel effect. Recently, many efforts have been made on doping 2D films to create p‐n junctions, in which plasma implantation has been placed great expectations due to its CMOS process compatibility. However, ultrathin vertical 2D p‐n homostructure with excellent rectification behaviors have rarely been studied so far. Herein, MoS2 van der Waals p‐n homojunctions are fabricated by highly efficient N2 plasma implantation. Kelvin probe force microscope reveals the surface potential difference of ≈130 mV between n‐MoS2 and p‐MoS2. The fabricated field‐effect transistor (FET) presents a high rectification ratio up to 3.1 × 10–3 at the gate bias VGS = 20 V, which is over 20 times larger than that of the vertical homojunction obtained by surface chemical doping. The forward current is mainly dominated by both the interlayer recombination and band‐to‐band tunneling, while the ultra‐low reverse current in the order of 10 pA is governed by direct tunneling. The results demonstrate a new CMOS‐compatible way to fabricate vertical 2D homojunction, which is the basic structure of many low‐dimensional microelectronic devices.
Sequentially Fluorinated Polythiophene Donors for High‐Performance Organic Solar Cells with 16.4% Efficiency
Authors: Jeong Dahyun , Kim Geon‐U , Lee Dongchan , Seo Soodeok , Lee Seungjin , Han Daehee , Park Hyeonjung , Ma Biwu , Cho Shinuk , Kim Bumjoon J.
Published: July 2022

Polythiophenes (PTs) have attracted considerable interest for application in organic solar cells (OSCs) owing to their simple molecular structures and low‐cost synthesis. However, the power conversion efficiencies (PCEs) of PT‐based OSCs are lower than those of state‐of‐the‐art OSCs. Herein, the development of two sequentially fluorinated PT donors (PT‐2F and PT‐4F) is reported for realizing highly efficient OSCs. PT‐2F and PT‐4F are designed to contain two and four fluorine atoms, respectively, per repeating unit to decrease their highest occupied molecular orbital energy levels and increase the open‐circuit voltages of the OSCs. Importantly, the PT‐4F polymers exhibit high backbone rigidity and the desired temperature‐dependent aggregation behavior, affording well‐developed crystalline structures in thin films for efficient charge transport. These beneficial features promote the construction of an optimal blend morphology of PT‐4F:small‐molecule acceptor with a suitable energy offset and low energetic disorder. Thus, the PT‐4F‐based binary and ternary OSCs achieve high PCEs of 15.6% and 16.4%, respectively.
Discriminating Soft Actuators’ Thermal Stimuli and Mechanical Deformation by Hydrogel Sensors and Machine Learning
Authors: Sun Zhaojia , Wang Shuyu , Zhao Yuliang , Zhong Zhitao , Zuo Lei
Published: July 2022

Multimodal sensing is crucial for soft robots’ environmental interaction and closed‐loop control. The sensing signals of mechanical deformation and temperature changes are often hard to differentiate manually. Herein, two hydrogel sensors are used for simultaneously proprioceptive, thermoceptive, and mechanoreceptive sensing. These stretchable sensors show high sensitivity to strain and temperature changes. Then, a machine learning model composed of a 1D convolutional neural network and a feed‐forward neural network is utilized to decode the sensing signal for various stimuli identification. It is demonstrated that the proposed method can accurately predict the soft actuator's body posture changes, such as bending, twisting, and stretching. In addition, the model can discern contact events with or without thermal stimuli. This data‐driven method for multimodal sensing discrimination might pave the way for future intelligent soft robots.
Surface Functionalization of Surfactant‐Free Particles: A Strategy to Tailor the Properties of Nanocomposites for Enhanced Thermoelectric Performance
Authors: Chang Cheng , Liu Yu , Ho Lee Seung , Chiara Spadaro Maria , Koskela Kristopher M. , Kleinhanns Tobias , Costanzo Tommaso , Arbiol Jordi , Brutchey Richard L. , Ibáñez Maria
Published: July 2022

The broad implementation of thermoelectricity requires high‐performance and low‐cost materials. One possibility is employing surfactant‐free solution synthesis to produce nanopowders. We propose the strategy of functionalizing “naked” particles’ surface by inorganic molecules to control the nanostructure and, consequently, thermoelectric performance. In particular, we use bismuth thiolates to functionalize surfactant‐free SnTe particles’ surfaces. Upon thermal processing, bismuth thiolates decomposition renders SnTe‐Bi2S3 nanocomposites with synergistic functions: 1) carrier concentration optimization by Bi doping; 2) Seebeck coefficient enhancement and bipolar effect suppression by energy filtering; and 3) lattice thermal conductivity reduction by small grain domains, grain boundaries and nanostructuration. Overall, the SnTe‐Bi2S3 nanocomposites exhibit peak z T up to 1.3 at 873 K and an average z T of ≈0.6 at 300–873 K, which is among the highest reported for solution‐processed SnTe.
Photophysical Properties of Fluorescent Labels: A Meta‐Analysis to Guide Probe Selection Amidst Challenges with Available Data
Authors: Cavazos‐Elizondo Daniela , Aguirre‐Soto Alan
Published: July 2022

Invited for this month‘s cover is the group of Prof. Alan Aguirre‐Soto, head of the Macromolecular and Photo‐sciences Lab at Tecnologico de Monterrey, Mexico. The cover picture shows a set of molecular, macromolecular and nanoparticle fluorescent tags through space alluding to the expanding repertoire of fluorescent probes for which photophysical data is currently limited. More information can be found in the Review by D. Cavazos‐Elizondo and A. Aguirre‐Soto.
Feste Gashydrate II. Struktur und Raumchemie
Authors: v. Stackelberg M. , Müller H. R.
Published: July 2022

Durch röntgenographische Untersuchungen sind bei den Gashydraten zwei kubische Strukturen festgestellt worden:

Struktur I. a ≃ 12 Å mit 46 Wassermolekeln in der Elementarzelle, die ein Gerüst mit 2 Hohlräumen der Koordinationszahl 20 und 6 Hohlräumen der Koordinationszahl 24 bilden. Die Idealzusammensetzung bei Besetzung aller Hohlräume mit Gasmolekeln M ist daher M · 53/4 H2O.

Struktur II. a ≃ 17,3 Å mit 136 Wassermolekeln, die ein Gerüst mit 16 Hohlräumen mit der Koordinationszahl 20 und 8 großen Hohlräumen mit der Koordinationszahl 28 bilden. Diese Hydratstruktur wird von Stoffen (meist Flüssigkeiten) mit größeren Molekeln (6 bis 7 Å Durchmesser) gebildet, wobei nur die großen

Hohlräume besetzt werden. Die Idealzusammensetzung ist also M · 17H2O.

Die kleinen Hohlräume der Struktur II können zusätzlich durch kleine Molekeln besetzt werden, und zwar entweder unter Bildung einer Mischphase (z.B. CCl4‐N2‐Hydrat) mit druckabhängigem Gehalt an kleinen Molekeln oder unter Bildung einer Verbindung mit nur temperaturabhängigem Dissoziationsdruck. Letzteres ist der Fall, wenn die kleinen Hohlräume mit H2S oder H2Se besetzt werden. Dies sind die de Forcrandschen„ Doppelhydrate”︁, deren Idealzusammensetzung demnach M · 2H2S · 17H2O ist.

Die Bedingungen für die Bildung von Hydraten der hier behandelten Art werden festgelegt. Neben den Bedingungen einer homöopolaren nicht salzartigen Natur der Hydratbildner, der Nichtmischbarkeit mit Wasser (Unfähigkeit zur Wasserstoffbrückenbindung) und einer genügenden Kleinheit der v. d. Waalsschen Kräfte (K. P. unter 60° C) ist die richtige Größe der Molekeln entscheidend. Es ist anzunehmen, daß die Molekeln in den Hohlräumen rotieren.
Effect of halide ions on the fluorescence properties of 3‐aminoquinoline in aqueous medium
Authors: Pandey Nupur , Pant Sanjay , Mehata Mohan Singh
Published: July 2022

Fluorescence (FL) quenching of 3‐aminoquinoline (3AQ) by halide ions
has been explored in an aqueous acidic medium using the steady‐state and time‐domain FL measurement techniques. The halide ions showed no significant change in the absorption spectra of 3AQ in an aqueous acidic medium. The FL intensity was strongly quenched by
ions and the order of FL quenching by halide ions was
. The decrease in FL lifetime along with the reduction in FL intensity of 3AQ suggested the dynamic nature of quenching. The obtained
values were 328
for
ions and 119
for
ions and the
values were ~
and
, respectively. The observations suggested that the likely governing mechanism for FL quenching may be an electron transfer process and the involvement of the heavy atom effects.
hMSCs in contact with DMSO for cryopreservation: Experiments and modeling of osmotic injury and cytotoxic effect
Authors: Traversari Gabriele , Delogu Francesco , Aparicio Santiago , Cincotti Alberto
Published: July 2022

In this study a combined analysis of osmotic injury and cytotoxic effect useful for the optimization of the cryopreservation process of a cell suspension is carried out. The case of human Mesenchymal Stem Cells (hMSCs) from Umbilical Cord Blood (UCB) in contact with dimethyl sulfoxide (DMSO) acting as Cryo‐Protectant Agent (CPA) is investigated from the experimental as well as the theoretical perspective. The experimental runs are conducted by suspending the cells in hypertonic solutions of DMSO at varying osmolality, system temperature, and contact times; then, at room temperature, cells are pelleted by centrifugation and suspended back to isotonic conditions. Eventually, cell count and viability are measured by means of a Coulter counter and flow‐cytometer, respectively. Overall, a decrease in cell count and viability results when DMSO concentration, temperature, and contact time increase. A novel mathematical model is developed and proposed to interpret measured data by dividing the cell population between viable and nonviable cells. The decrease of cell count is ascribed exclusively to the osmotic injury caused by expansion lysis: excessive swelling causes the burst of both viable as well as nonviable cells. On the other hand, the reduction of cell viability is ascribed only to cytotoxicity which gradually transforms viable cells into nonviable ones. A chemical reaction engineering approach is adopted to describe the dynamics of both phenomena: by following the kinetics of two chemical reactions during cell osmosis inside a closed system it is shown that the simultaneous reduction of cell count and viability may be successfully interpreted. The use of the Surface Area Regulation (SAR) model recently proposed by the authors allows one to avoid the setting in advance of fixed cell Osmotic Tolerance Limits (OTLs), as traditionally done in cryopreservation literature to circumvent the mathematical simulation of osmotic injury. Comparisons between experimental data and theoretical simulations are provided: first, a nonlinear regression analysis is performed to evaluate unknown model parameters through a best‐fitting procedure carried out in a sequential fashion; then, the proposed model is validated by full predictions of system behavior measured at operating conditions different from those used during the best‐fit procedure.