bluuebunny/crossref_metadata_2025 huggingface dataset:
Perfil de los usuarios de centros deportivos según sus expectativas
Authors: Aparicio-Chueca Pilar , Elasri-Ejjaberi Amal , Triadó-Iverm Xavier
Published: August 2021

Las necesidades de los usuarios de centros deportivos han ido cambiando en los últimos años. Por este motivo se hacen necesarios tanto el análisis del perfil de usuarios como la evaluación de la satisfacción de los clientes y su relación con las expectativas del servicio. Analizado desde la teoría clásica de la desconfirmación de expectativas, el presente estudio tiene como objetivo revisar los perfiles de tres grupos de usuarios en centros deportivos: aquellos para quienes no se cumplen sus expectativas, los que sí las ven satisfechas y aquellos que creen que se han superado. Los datos fueron recogidos mediante una encuesta a usuarios de tres centros deportivos municipales de Barcelona. Un análisis ANOVA revela que la edad es una variable clave, siendo los usuarios jóvenes los que tienen una percepción más positiva de la oferta, mientras que el grupo de usuarios de edad media ven cumplidas sus expectativas en un grado menor. Además, los resultados demuestran que existe un conjunto de usuarios que a pesar de haber manifestado que el centro no cumple con sus expectativas, siguen como abonados en el mismo, contradiciendo la teoría de la desconfirmación de expectativas. Se exponen, finalmente, un conjunto de aplicaciones prácticas dirigidas al análisis y la gestión de las expectativas de los usuarios y el establecimiento de políticas de permanencia.

The needs from users of sports centers have been changing in recent years. For this reason, it is necessary to analyse users’ profile and its relationship with service expectations. Analysed from the classical theory of disconfirmation of expectations, the present study aims to review the profiles of three user groups in sports centers: those for whom their expectations are not met, those who seems satisfied and those who believe that they have been overcome with the service. The data was collected through a survey of users of three municipal sports centers in Barcelona. An ANOVA analysis reveals that age is a key variable, with young users having a more positive perception of the offer, while the group of middle-aged users seems fulfil their expectations in a lesser degree. In addition, the results show that there is a set of users who despite having stated that the center does not meet their expectations, continue as subscribers in it, contradicting the theory of disconfirmation of expectations. Finally, a set of practical applications aimed at the analysis, and management, of user expectations. Also, some fidelity policies are exposed.
Polyethylene Gel Volume Fraction (Cross-linked Percentage) Measurement Using DSC Technique
Authors: Safaei Shouresh
Published: August 2021

In this paper, the measurement of the crosslinking percentage (gel volume fraction) of polyethylene materials by using DSC technique is presented. To obtain the calibration curve, the networked samples of ASTMD 2765-01 corresponding to the curves of pure melt samples at the start of the reaction were used. The resulting calibration curve was used to predict the percentage of polyethylene cross-linked in a continuous process, and these results were compared with those obtained from D 2765-01, which resulted in excellent agreement between the two states. This technique is faster and cheaper and requires less raw material, the product does not release any harmful substances and is ASTM correct.
Logarithmic Ratio-Type Estimator of Population Coefficient of Variation
Authors: Yunusa M. A. , Audu A. , Musa N. , Beki D. O. , Rashida A. , Bello A. B. , Hairullahi M. U.
Published: August 2021

The estimation of population coefficient of variation is one of the challenging aspects in sampling survey techniques for the past decades and much effort has been employed to develop estimators to produce its efficient estimate. In this paper, we proposed logarithmic ratio type estimator for the estimating population coefficient of variation using logarithm transformation on the both population and sample variances of the auxiliary character. The expression for the mean squared error (MSE) of the proposed estimator has been derived using Taylor series first order approximation approach. Efficiency conditions of the proposed estimator over other estimators in the study has also been derived. The empirical study was conducted using two-sets of populations and the results showed that the proposed estimator is more efficient. This result implies that, the estimate of proposed estimator will be closer to the true parameter than the estimates of other estimators in the study.
Effects of Mycorrhizal Inoculant on the Quality of Macropropagated Seeds and the Agronomic Performance of Plantain (Musa spp.)
Authors: Voko Don-Rodrigue Rosin Bi , Amoa Jesus Amoa , Tonessia Charlotte Dolou , Konate Ibrahim
Published: August 2021

The difficulties of nurserymen and producers of plantains in Côte d’Ivoire are the high mortality rate of seedlings and the delays of growth in the field. The aim of this study is to improve quality and agronomic performance of plantain seedlings produced by PIF technique (plantain seedlings production based on macropropagation). The plantain shoot bulbs were inoculated before being placed in the germinator and seedlings from germinator were inoculated again during the weaning phase at nursery with AMFs (Rhizophagus intraradices). Root mycorrhizal colonization, growth parameters such as girth, height, total leaf area, biomass and entry into production were measured in nursery and on the field. The results showed that the root colonization rate of the plants inoculated with R. intraradices inoculum was higher (30.59%) than that of the native arbuscular mycorrhizal fungi (2.78%). All inoculated plants survived while non-inoculated plants had 27.69% of mortality rate. Inoculated plants had higher growth than non-inoculated plants. The organs of inoculated plants also had higher biomass than non-inoculated plants. Eleven months after planting, nearly 50% of the inoculated plants had started production, while only 5.67% of the non-inoculated plants had started production. Mycorrhization improved the vigor and vegetative growth of plantain seedlings. It could therefore be used as a solution for a sustainable plantain culture.
Qualitative Traits of Dry Rose Flowers ‘Taj Mahal’ as Influenced by Dehydration Methods
Authors: Narjinary M. , Khan Arpita Mandal , Maitra S. , Sarkar I. , Pal P. K.
Published: August 2021

Aims: To optimize drying technique for the popular Dutch rose cultivar, Taj Mahal, by evaluating different drying methods and appraising the physical, biochemical and sensory quality of the product.

Study Design: Completely Randomized Design.

Place and Duration of Study: Department of Floriculture, Medicinal and Aromatic Plants, Faculty of Horticulture, Uttar Banga Krishi Viswavidyalaya, during 2019-2020

Methodology: Flowers of rose cultivar ‘Taj Mahal’, at their prime beauty i.e., half-opened bud stage, were subjected to embedded drying in silica gel at six different conditions viz. at room temperature (T1), in hot air oven at 45°C, (T2) and at 60°C, (T3) in micro-wave oven at 100% power level (T4), 80% power level (T5) and at 60% power level (T6). The quality of the ensuing dehydrated flowers was judged with respect to colour, weight, volume shrinkage and anthocyanin and carotenoid contents. Temperature during drying and time to reach optimum dehydrated condition under different drying techniques were recorded. Sensory evaluation for the quality of the products was done after six months of storage.

Results: The time taken for optimum drying ranged from 120 hours in case of room temperature drying (25.1°C) to 3 minutes in microwave oven on high power i.e., 100% (130.4°C). Significant variation in final weight of the product was recorded between 18.34% to 28% of the fresh weight. Minimum shrinkage (42.85%) was noted in room drying (T1) and hot air oven drying at 60°C (43.53%). Maximum anthocyanin concentration (3.528 mg/g) was recorded in flowers dried at room temperature, whereas, minimum among the dried flowers, was recorded in microwave oven drying at 100% power level (1.439 mg/g). Maximum Carotenoid content (16.780 µg/g) was recorded in flowers dried in hot air oven at 45°C. Out of six treatments in the present study, maximum sensory score (30.38 out of 36) was gathered by T2, which was at par with T1 and T5.

Conclusion: Dehydrating ‘Taj Mahal’ rose flowers by embedding in silica gel and drying under room temperature (25°C) for 120 hours or hot air oven at 45°C for 27.5 hours or microwave oven at 80% power level for 3.5 minutes can be recommended for commercial dry flower production.
Spatial Variability of Physical and Chemical Properties in Northern Himalayas of Kashmir Province
Authors: Javed Ayman , Bhat Shaista Nazir , Yadav Rajnish , Wani Mushtaq Ahmad
Published: August 2021

Due to geological and pedological soil-forming factors, spatial variability of soil physical and chemical properties across the agricultural fields is intrinsic by its nature, however variability may arise from tillage and other soil management practices. The main aim of this survey was to investigate the spatial variability of soil physical along with chemical properties and the preparation of thematic maps across the study area. The physico-chemical properties determined were Particle size distribution, Bulk density, Particle density, total porosity, soil resistance, soil pH, Electrical conductivity (EC), Organic carbon (OC), Nitrogen(N), Phosphorus (P), Potassium(K). Soil samples were collected from 45 sites using Geographical Positioning System (GPS) under different land-use systems. The results showed normal distribution for Sand, silt, particle density, electrical conductivity, and soil pH. Organic carbon recorded the maximum coefficient of variation (82.2%) and soil particle density (5.66%) the minimum. Soil macronutrients were medium in range excluding phosphorus which was found inadequate in the watershed. Employing such analytic work, it is feasible to devise accurate soil management practices and an unerring soil sampling system for taking efficient management judgments that result in sustainable agricultural production.
Antibiotic Resistance Patterns of Escherichia coli Detected in Pig Faecal Samples from Anambra State
Authors: Kyrian-Ogbonna E. A. , Ekwealor I. A. , Eze E. N. , Eluba R. A. , Nworji E. C. , Ogah E. C. , Oladejo A. A.
Published: August 2021

Aim: Pig farmers use antibiotics for therapeutic, metaphylaxis, prophylaxis and growth promotion in their farm animals. This work was aimed to determine the antibiogram of Escherichia coli isolated from pig faecal samples from pig farms in the three senatorial zones of Anambra State.

Materials and Methods: A total of 80 faecal samples were collected from forty pig farms in the three senatorial zones (Anambra North, Anambra Central and Anambra South) of Anambra State from February, 2018-January, 2019 and analyzed microbiologically using MacConkey agar and Eosin Methylene Blue (EMB) Agar and appropriate culture conditions. Recovered isolates were further characterized based on their morphological and biochemical features. Antimicrobial susceptibility of the isolates was tested to 10 conventional antibiotics using Kirby Bauer Disc Diffusion method.

Results: A total of 140 Escherichia coli isolates were recovered and characterized. Percentage occurrences were 36.4, 30.1 and 33.5 in Anambra North, Anambra Central and Anambra South respectively. Antimicrobial susceptibility testing of the bacterial isolates revealed that resistance of the isolates ranged from 7% resistance to Imipenem to 67% resistance to Streptomycin. A one way analysis of variance showed no significant difference (p >0.05) in resistance to imipenem, amoxicillin/clavulanic, ceftazidime, tetracycline, gentamicin, ceftriaxone, ciprofloxacin, trimethoprim/sulfamethoxazol and significant difference (p < 0.05) in resistance to streptomycin and cefotaxime in the three senatorial zones studied. 51.4% of the isolates were multidrug resistant.

Conclusion and Recommendation: Misuse and overuse of antibiotics in piggery have resulted in antibiotic resistance in isolates from pig faecal samples. Policies regarding prudent use of antibiotics in pig farms should be enforced to reduce the spread of antibiotic resistance.
In Situ Synthesis of Molybdenum Carbide Nanoparticles Incorporated into Laser‐Patterned Nitrogen‐Doped Carbon for Room Temperature VOC Sensing
Authors: Wang Huize , Delacroix Simon , Zieleniewska Anna , Hou Jing , Tarakina Nadezda V. , Cruz Daniel , Lauermann Iver , Ferguson Andrew J. , Blackburn Jeffrey L. , Strauss Volker
Published: August 2021

Carbon laser‐patterning (CLaP) is emerging as a new tool for the precise and selective synthesis of functional carbon‐based materials for on‐chip applications. The aim of this work is to demonstrate the applicability of laser‐patterned nitrogen‐doped carbon (LP‐NC) for resistive gas‐sensing applications. Films of pre‐carbonized organic nanoparticles on polyethylenetherephthalate are carbonized with a CO2‐laser. Upon laser‐irradiation a compositional and morphological gradient in the films is generated with a carbon content of 92% near the top surface. The specific surface areas of the LP‐NC are increased by introducing sodium iodide (NaI) as a porogen. Electronic conductivity and surface area measurements corroborate the deeper penetration of the laser‐energy into the film in the presence of NaI. Furthermore, impregnation of LP‐NC with MoC1−x (<10 nm) nanoparticles is achieved by addition of ammonium heptamolybdate into the precursor film. The resulting doping‐sensitive nano‐grain boundaries between p‐type carbon and metallic MoC1−x lead to an improvement of the volatile organic compounds sensing response of ΔR/R0 = −3.7% or −0.8% for 1250 ppm acetone or 900 ppm toluene at room temperature, respectively, which is competitive with carbon‐based sensor materials. Further advances in sensitivity and in situ functionalization are expected to make CLaP a useful method for printing selective sensor arrays.
Combined Bulk and Surface Passivation in Dimensionally Engineered 2D‐3D Perovskite Films via Chlorine Diffusion
Authors: Mahmud Md Arafat , Pham Huyen T. , Duong The , Yin Yanting , Peng Jun , Wu Yiliang , Liang Wensheng , Li Li , Kumar Anand , Shen Heping , Walter Daniel , Nguyen Hieu T. , Mozaffari Naeimeh , Tabi Grace Dansoa , Andersson Gunther , Catchpole Kylie R. , Weber Klaus J. , White Thomas P.
Published: August 2021

Dimensional engineering of perovskite films is a promising pathway to improve the efficiency and stability of perovskite solar cells (PSCs). In this context, surface or bulk passivation of defects in 3D perovskite film by careful introduction of 2D perovskite plays a key role. Here the authors demonstrate a 2D perovskite passivation scheme based on octylammonium chloride, and show that it provides both bulk and surface passivation of 1.6 eV bandgap 3D perovskite film for highly efficient (≈23.62%) PSCs with open‐circuit voltages up to 1.24 V. Surface and depth‐resolved microscopy and spectroscopy analysis reveal that the Cl− anion diffuses into the perovskite bulk, passivating defects, while the octylammonium ligands provide effective, localized surface passivation. The authors find that the Cl− diffusion into the perovskite lattice is independent of the 2D perovskite crystallization process and occurs rapidly during deposition of the 2D precursor solution. The annealing‐induced evaporation of Cl from bulk perovskite is also inhibited in 2D–3D perovskite film as compared to pristine 3D perovskite, ensuring effective bulk passivation in the relevant film.
Minimizing Optical Energy Losses for Long‐Lifetime Perovskite Light‐Emitting Diodes
Authors: Ye Yong‐Chun , Li Yan‐Qing , Cai Xiao‐Yi , Zhou Wei , Shen Yang , Shen Kong‐Chao , Wang Jing‐Kun , Gao Xingyu , Zhidkov Ivan S. , Tang Jian‐Xin
Published: August 2021

Regardless of the rapid advance on perovskite light‐emitting diodes (PeLEDs), the lack of long‐term operational stability hinders the practicality of this technology. Particularly, thermal management is indispensable to control the Joule heating induced by charge transport and parasitic re‐absorption of internally confined photons. Herein, a synergetic device architecture is proposed for minimizing the optical energy losses in PeLEDs toward high efficiency and long lifetime. By adopting a carefully modified perovskite emitter in combination with an improved light outcoupling structure, red PeLEDs emitting at 666 nm achieve a peak external quantum efficiency of 21.2% and an operational half‐lifetime of 4806.7 h for an initial luminance of 100 cd m‐2. The enhanced light extraction from trapped modes can efficiently reduce the driving current and suppress optical energy losses in PeLEDs, which in turn ameliorate the heat‐induced device degradation during operation. This work paves the way toward high‐performance PeLEDs for display and lighting applications in the future.
Multifunctional Hybrid Hydrogel Enhanced Antitumor Therapy through Multiple Destroying DNA Functions by a Triple‐Combination Synergistic Therapy
Authors: Zhang Jiamin , Yang Lijun , Huang Fan , Zhao Cuicui , Liu Jinjian , Zhang Yumin , Liu Jianfeng
Published: August 2021

Brachytherapy, as an effective setting for precise cancer therapy in clinic, can lead to serious DNA damage. However, its therapeutic efficacy is always limited by the DNA self‐repair property, tumor hypoxia‐associated radiation resistance as well as inhomogeneous distribution of the radioactive material. Herein, a multifunctional hybrid hydrogel (131I‐hydrogel/DOX/GNPs aggregates) is developed by loading gold nanoparticle aggregates (GNPs aggregates) and DOX into a radionuclide iodine‐131 (131I) labelled polymeric hydrogels (131I‐PEG‐P(Tyr)8) for tumor destruction by completely damaging DNA self‐repair functions. This hybrid hydrogel exhibits excellent photothermal/radiolabel stability, biocompatibility, and fluorescence/photothermal /SPECT imaging properties. After local injection, the sustained releasing DOX within tumor greatly inhibits the DNA replication. Meanwhile, GNPs aggregates as a radiosensitizer and photosensitizer show a significant improvement of brachytherapeutic efficacy and cause serious DNA damage. Simultaneously, GNPs aggregates induce mild photothermal therapy under 808 nm laser irradiation, which not only inhibits self‐repair of the damaged DNA but also effectively relieves tumor hypoxic condition to enhance the therapeutic effects of brachytherapy, leading to a triple‐synergistic destruction of DNA functions. Therefore, this study provides a highly efficient tumor synergistic therapy platform and insight into the synergistic antitumor mechanism in DNA level.
Grain Boundaries in Methylammonium Lead Halide Perovskites Facilitate Water Diffusion
Authors: Tian Fuyu , Feng Weiqiang , Xing Bangyu , He Xin , Saidi Wissam A. , Zhang Lijun
Published: August 2021

Organic–inorganic hybrid perovskites such as methylammonium lead iodide (MAPbI3) materials have recently attracted great attention due to their potential for photovoltaic applications. The performance and stability of these perovskite solar cells are sensitive to water and moisture in an ambient environment. Thus, an understanding of how water influences MAPbI3 and particularly the role of grain boundary (GB) defects is important for developing appropriate mitigation strategies. Herein, water molecular diffusion in ∑5‐(210) GB is investigated and compared with pristine MAPbI3 using first‐principles calculations. Water diffusion along the ∑5‐(210) GB is found to be facile with a 0.07 eV energy barrier while diffusion barrier from GB core to bulk is 0.24 eV. In contrast, the diffusion process in bulk MAPbI3 is relatively large 0.70 eV due to water interactions with the Pb–I network. Further, it is shown that water is more stable in the GB region compared with the pristine system. Thus, the strong thermodynamic and kinetic tendencies for water segregation to the GBs in MAPbI3 suggests that improving the crystallinity of MAPbI3 is an effective strategy to slow down water degradation processes in agreement with recent experimental results.
Nutrient management for sustainable food crop intensification in African tropical savannas
Authors: Wortmann Charles S. , Stewart Zachary
Published: August 2021

Increased fertilizer use is often an essential component of sustainable intensification for improved food security and economic growth in the upper elevation tropical savanna (UTS) and lower elevation tropical savanna (LTS) of Africa. The UTS and LTS are large “breadbasket” areas with little fertilizer use due to financial and other constraints. Farmers’ perceptions of high profit opportunity with low risk are often major drivers of adoption. Representative crop nutrient response functions are needed to maximize farm‐level profits from fertilizer use. Such functions were determined from results of past research, and profit potentials were evaluated. The mean yield increases due to fertilizer application at the economically optimum rate, relative to yield with no fertilizer applied, were as follows: 41% for cassava (Manihot esculenta Crantz), 18% for cowpea [Vigna unguiculata (L.) Walp.], 16% for groundnut (Arachis hypogaea L.), 67% for maize (Zea mays L.), 50% for lowland rice (Oryza sativa L.), and 39% for sorghum [Sorghum bicolor (L.) Moench] in LTS, and 46% for bean (Phaseolus vulgaris L.), 81% for groundnut, 58% for maize, 96% for upland rice (Oryza sativa L. or Oryza glaberrima Steud.), 32% for sorghum, and 48% for soybean [Glycine max (L.) Merr.] in UTS. The profit potential varied greatly across nutrient rates applied to individual crops making optimized crop–nutrient–rate choices especially important for cases of financially constrained fertilizer use. Considerations for achieving widespread adoption of increased fertilizer use are discussed. Increased fertilizer use needs to be complemented by mitigation of diverse yield and socioeconomic constraints to meet the growing demand for food.
Relationship between the prehospital quick Sequential Organ Failure Assessment and prognosis in patients with sepsis or suspected sepsis: a population‐based ORION registry
Authors: Hirose Tomoya , Katayama Yusuke , Ogura Hiroshi , Umemura Yutaka , Kitamura Tetsuhisa , Mizushima Yasuaki , Shimazu Takeshi
Published: August 2021

Aim

The quick Sequential Organ Failure Assessment (qSOFA) was proposed for use as a simple screening tool for sepsis. In this study, we evaluated the relationship between the prehospital use of qSOFA and prognosis in patients with sepsis or suspected sepsis using the population‐based Osaka Emergency Information Research Intelligent Operation Network (ORION) registry, which compiles prehospital ambulance data and in‐hospital information.

Methods

The study enrolled 437,974 patients in the ORION registry from January 1 to December 31, 2016. We selected hospitalized patients with sepsis or suspected sepsis using the appropriate codes from the International Classification of Diseases revision 10. We excluded patients with: (i) missing data (outcome, Japan Coma Scale, respiratory rate, and blood pressure); (ii) respiratory rate ≥60/min; and (iii) blood pressure ≥250 mmHg. These measures were evaluated by ambulance personnel when they first contacted the patient in the prehospital setting. The primary end‐point was discharge to death.

Results

In total, 12,646 patients (median age, 78 [interquartile range, 65–85] years; male, n = 6,760 [53.5%]) were eligible for our analysis. In a multivariable logistic regression analysis adjusted for confounding factors, the proportion of patients discharged to death was significantly higher for those evaluated as qSOFA positive (≥2 points) than qSOFA negative (≤1 point) (265/2,250 [11.78%] vs. 415/10,396 [3.99%]; adjusted odds ratio 2.91; 95% confidence interval, 2.47–3.43; P < 0.0001). The specificity and sensitivity were 83.4% and 39.0%, respectively, and the area under the receiver operating characteristic curve for qSOFA positive was 0.61.

Conclusions

The qSOFA evaluated by ambulance personnel in the prehospital setting was significantly associated with prognosis in patients with sepsis or suspected sepsis.
Nanotechnologies and Nanomaterials in 3D (Bio)printing toward Bone Regeneration
Authors: Wang Zongliang , Agrawal Prajwal , Zhang Yu Shrike
Published: August 2021

The utilization of biomedical nanotechnologies and nanomaterials has surged in the field of 3D bone printing and bioprinting. As such, it is possible to reproduce the hierarchical structures and compositions of the native bone‐related tissues, allowing for regulating cell behaviors and tissue formation toward bone tissue engineering. The use of nanobiomedical systems may also enhance the shape fidelity and printability apart from endowing plentiful biological functions to the (bio)inks. Herein, first, the recently published literature on nanotechnologies and nanomaterials utilized for 3D bone (bio)printing is overviewed. Later, recent progress and challenges for osseous interface and vascularized bone reconstructions are discussed. Finally, the future prospectives and potential commercialization for 3D‐(bio)printed personalized bone implants are proposed.
Discrete Heteropolynuclear Yb/Er Assemblies: Switching on Molecular Upconversion Under Mild Conditions
Authors: Wang Jie , Jiang Yue , Liu Jiao‐Yang , Xu Hai‐Bing , Zhang Yue‐Xing , Peng Xu , Kurmoo Mohamedally , Ng Seik Weng , Zeng Ming‐Hua
Published: August 2021

The salts {[Ln2Ln*(Hhmq)3(OAc)3(hfac)2]+ [Ln*(hfac)3(OAc)(MeOH)]−} (Hhmq=2‐methanolquinolin‐8‐oxide, hfac=hexafluoroacetylacetonate; Ln, Ln*=Er, Gd, Yb) feature a discrete heteronuclear cation consisting of two types of lanthanide atoms. The quinolinoxy O‐atom serves as a μ2‐bridge to two Ln atoms and as a μ3‐bridge to all three atoms, with metal⋅⋅⋅metal distances being around 3.7 Å. For 1 ([Yb2Er]+), near‐infrared downshifted luminescence is switched to competitive upconversion luminescence upon irradiation by a 980 nm laser under an extremely low excitation power (0.288 W cm−2) through introduction of fluoride ions. The stability of 1 after addition of fluoride was confirmed by powder X‐ray diffraction and multistage mass spectrometry, associated with the 1H NMR of 6 ([La2Eu]+). More importantly, the at least 20‐fold enhancement of the quantum yield in non‐deuterated solvents at room temperature under low power densities (2 W cm−2) is the highest among the few molecular examples reported.
Palladium‐Catalyzed Cascade Carbonylation to α,β‐Unsaturated Piperidones via Selective Cleavage of Carbon–Carbon Triple Bonds
Authors: Ge Yao , Ye Fei , Yang Ji , Spannenberg Anke , Jiao Haijun , Jackstell Ralf , Beller Matthias
Published: August 2021

A direct and selective synthesis of α,β‐unsaturated piperidones by a new palladium‐catalyzed cascade carbonylation is described. In the presented protocol, easily available propargylic alcohols react with aliphatic amines to provide a broad variety of interesting heterocycles. Key to the success of this transformation is a remarkable catalytic cleavage of the present carbon–carbon triple bond by using a specific catalyst with 2‐diphenylphosphinopyridine as ligand and appropriate reaction conditions. Mechanistic studies and control experiments revealed branched unsaturated acid 11 as crucial intermediate.
Introducing A New Class of Sulfonyl Fluoride Hubs via Radical Chloro‐Fluorosulfonylation of Alkynes
Authors: Nie Xingliang , Xu Tianxiao , Hong Yuhao , Zhang Honghai , Mao Chenxi , Liao Saihu
Published: August 2021

Sulfonyl fluorides have widespread applications in many important fields, including ligation chemistry, chemical biology, and drug discovery. Therefore, new methods to increase the synthetic efficiency and expand the available structures of sulfonyl fluorides are highly in demand. Here, we introduce a new and powerful class of sulfonyl fluoride hubs, β‐chloro alkenylsulfonyl fluorides (BCASF), which can be constructed via radical chloro‐fluorosulfonyl difunctionalization of alkynes under photoredox conditions. BCASF molecules exhibit versatile reactivities and well undergo a series of transformations at the chloride site while keeping the sulfonyl fluoride group intact, including reduction, Suzuki coupling, Sonogashira coupling, as well as nucleophilic substitution with various nitrogen, oxygen, and sulfur nucleophiles. By using BCASF as a synthetic hub, a wide range of sulfonyl fluorides becomes readily accessible, such as cis alkenylsulfonyl fluorides, dienylsulfonyl fluorides, and ynenylsulfonyl fluorides, which are challenging or even not possible to synthesize before with the known methods. Moreover, further application of BCASF to the late‐stage modification of peptides and drugs is also demonstrated.
An Open‐Shell Coronoid with Hybrid Chichibabin–Schlenk Conjugation
Authors: Prajapati Bibek , Dang Duy‐Khoi , Chmielewski Piotr J. , Majewski Marcin A. , Lis Tadeusz , Gómez‐García Carlos J. , Zimmerman Paul M. , Stępień Marcin
Published: August 2021

A hexaradicaloid molecule with alternating Kekulé and non‐Kekulé connectivities between adjacent spin centers was obtained by fusing two conjugation motifs in Chichibabin and Schlenk hydrocarbons into a coronoid structure. 1H NMR, ESR, and SQUID experiments and computational analyses show that the system has a singlet ground state with a significant hexaradicaloid character (γ0=0.826, γ1=γ2=0.773). It has multiple thermally accessible high‐spin states (up to the septet), with uniform energy gaps of ca 1.0 kcal mol−1 between consecutive multiplicities. In line with its open‐shell character, the coronoid has a small electronic band gap (ca. 0.8 eV) and undergoes two consecutive one‐electron oxidations at low potentials, yielding cationic forms with extended near‐infrared absorption. The hexaradicaloid, which combines open‐shell and macrocyclic contributions to its π conjugation, is an example of a design strategy for multistate spin switches and redox‐amphoteric NIR dyes.
Designing Anion‐Type Water‐Free Zn2+ Solvation Structure for Robust Zn Metal Anode
Authors: Zhang Qiu , Ma Yilin , Lu Yong , Zhou Xunzhu , Lin Liu , Li Lin , Yan Zhenhua , Zhao Qing , Zhang Kai , Chen Jun
Published: August 2021

Rechargeable aqueous Zn batteries are potential for large‐scale electrochemical energy storage due to their low cost and high security. However, Zn metal anode suffers from the dendritic growth and interfacial hydrogen evolution reaction (HER), resulting in the deterioration of electrode/battery performance. Here we propose that both dendrites and HER are related to the water participated Zn2+ solvation structure‐Zn(H2O)62+ and thus can be resolved by transforming Zn(H2O)62+ to an anion‐type water‐free solvation structure‐ZnCl42−, which is achieved in traditional ZnSO4 aqueous electrolyte after adding chloride salt with a bulky cation (1‐ethyl‐3‐methylimidazolium chloride). The elimination of cation‐water interaction suppresses HER, while the electrostatic repulsion between Zn tips and the anion solvation structure inhibits dendrite formation. As a result, the electrolyte shows uniform Zn deposition with an average Zn plating/stripping Coulombic efficiency of ≈99.9 %, enabling a capacity retention of 78.8 % after 300 cycles in anode‐free Zn batteries with pre‐zincificated polyaniline as the cathode. This work provides a novel electrolyte design strategy to prevent HER and realize long‐lifespan metal anode.
A Selection of Macrocyclic Peptides That Bind STING From an mRNA‐Display Library With Split Degenerate Codons
Authors: Lin Chi‐Wang , Harner Mary J. , Douglas Andrew E. , Lafont Virginie , Yu Fei , Lee Ving G. , Poss Michael A. , Swain Joanna F. , Wright Martin , Lipovšek Daša
Published: August 2021

Recent improvements in mRNA display have enabled the selection of peptides that incorporate non‐natural amino acids, thus expanding the chemical diversity of macrocycles beyond what is accessible in nature. Such libraries have incorporated non‐natural amino acids at the expense of natural amino acids by reassigning their codons. Here we report an alternative approach to expanded amino‐acid diversity that preserves all 19 natural amino acids (no methionine) and adds 6 non‐natural amino acids, resulting in the highest sequence complexity reported to date. We have applied mRNA display to this 25‐letter library to select functional macrocycles that bind human STING, a protein involved in immunoregulation. The resulting STING‐binding peptides include a 9‐mer macrocycle with a dissociation constant (KD) of 3.4 nM, which blocks binding of cGAMP to STING and induces STING dimerization. This approach is generalizable to expanding the amino‐acid alphabet in a library beyond 25 building blocks.
A Family of Heterobimetallic Cubes Shows Spin‐Crossover Behaviour Near Room Temperature
Authors: Hardy Matthias , Tessarolo Jacopo , Holstein Julian J. , Struch Niklas , Wagner Norbert , Weisbarth Ralf , Engeser Marianne , Beck Johannes , Horiuchi Shinnosuke , Clever Guido H. , Lützen Arne
Published: August 2021

Using 4‐(4′‐pyridyl)aniline as a simple organic building block in combination with three different aldehyde components together with metal(II) salts gave three different Fe8Pt6‐cubes and their corresponding Zn8Pt6 analogues by employing the subcomponent self‐assembly approach. Whereas the use of zinc(II) salts gave rise to diamagnetic cages, iron(II) salts yielded metallosupramolecular cages that show spin‐crossover behaviour in solution. The spin‐transition temperature T1/2 depends on the incorporated aldehyde component, giving a construction kit for the deliberate synthesis of spin‐crossover compounds with tailored transition properties. Incorporation of 4‐thiazolecarbaldehyde or N‐methyl‐2‐imidazole‐carbaldehyde yielded cages that undergo spin‐crossover around room temperature whereas the cage obtained using 1H‐4‐imidazolecarbaldehyde shows a spin‐transition at low temperatures. Three new structures were characterized by synchrotron X‐ray diffraction and all structures were characterized by mass spectrometry, NMR and UV/Vis spectroscopy.
Phase‐Dependent Electrocatalytic CO2 Reduction on Pd3Bi Nanocrystals
Authors: Jia Lin , Sun Mingzi , Xu Jie , Zhao Xuan , Zhou Rui , Pan Binbin , Wang Lu , Han Na , Huang Bolong , Li Yanguang
Published: August 2021

Alloying is a general strategy for modulating the electronic structures of catalyst materials. Compared to more common solid–solution alloys, intermetallic alloys feature well‐defined atomic arrangements and provide the unique platform for studying the structure‐performance correlations. It is, unfortunately, synthetically challenging to prepare the nanostructures of intermetallic alloys for catalysis research. In this contribution, we prepare intermetallic Pd3Bi nanocrystals of a uniform size via a facile solvothermal method. These nanocrystals can phase‐transform into solid solution alloy via thermal annealing while retaining a similar composition and size. In 0.1 M KHCO3 aqueous solution, the intermetallic Pd3Bi can selectively reduce CO2 to formate with high selectivity (≈100 %) and stability even at <‐0.35 V versus reversible hydrogen electrode, whereas the solid solution alloy has limited formate selectivity of <60 %. Such unique phase‐dependence is understood via theoretical simulations showing that the crystallographic ordering of Pd and Bi atoms within intermetallic alloys can suppress CO poisoning and enhance the *OCHO adsorption during electrochemical CO2 reduction to formate.
Ball‐Milling Induced Debonding of Surface Atoms from Metal Bulk for Construing High‐Performance Dual‐Site Single‐Atom Catalysts
Authors: Wang Huilin , Wang Xiao , Pan Jing , Zhang Lingling , Zhao Meng , Xu Jing , Liu Bo , Shi Weidong , Song Shuyan , Zhang Hongjie
Published: August 2021

One of the most pressing challenges in single‐atom catalysis is the manipulation of the coordination environment of central metals to maximize the catalyst performance. Herein, we fabricated a high‐performance catalyst (Co‐SNC) by introducing S into the neighboring position of the Co‐N4 coordination. The developed ball‐milling method enabled large‐scale synthesis, that over 4.7 g of Co‐SNC can be produced in one pot. In benzylamine coupling reaction, Co‐SNC exhibited the highest conversion of 97.5 % with 99 % selectivity toward N‐benzylidenebenzylamine in 10 h among various Co catalysts. Density functional theory calculations revealed the crucial role of S atoms, which serve as the active sites for O2 activation, leaving the Co atoms free to adsorb benzylamine. Consequently, the adsorption energies of O2 and benzylamine were significantly increased. Our strategy suggests a feasible approach to enhance catalytic performance by delicately integrating dual active sites into a single catalyst unit.
The First High‐Pressure Chromium Oxonitridoborate CrB4O6N—an Unexpected Link to Nitridosilicate Chemistry
Authors: Fuchs Birgit , Johrendt Dirk , Bayarjargal Lkhamsuren , Huppertz Hubert
Published: August 2021

CrB4O6N crystallizes in the non‐centrosymmetric space group P63mc (no. 186) with the lattice parameters a=5.1036(1), c=8.3519(3) Å, and a volume of 188.40(1) Å3. It was synthesized in a high‐pressure/high‐temperature experiment at 7 GPa and 1673 K and represents the first high‐pressure oxonitridoborate. It is built up of starlike‐shaped entities of four BO3N tetrahedra, connected via one common nitrogen atom that resembles the fourfold‐coordinated nitrogen atoms in the homeotypic nitridosilicates MYbSi4N7 (M=Sr, Ba). Building up a network with channels that contain the Cr3+ ions, CrB4O6N contains for the first time a tetrahedral building unit in contrast to trigonal planar B(O/N)3 entities in all other known oxonitridoborates. The structural relations as well as the results of spectroscopic measurements and calculations on the chromium oxonitridoborate are discussed.
Fabrication of Integrated Copper‐Based Nanoparticles/Amorphous Metal–Organic Framework by a Facile Spray‐Drying Method: Highly Enhanced CO2 Hydrogenation Activity for Methanol Synthesis
Authors: Mitsuka Yuko , Ogiwara Naoki , Mukoyoshi Megumi , Kitagawa Hiroshi , Yamamoto Tomokazu , Toriyama Takaaki , Matsumura Syo , Haneda Masaaki , Kawaguchi Shogo , Kubota Yoshiki , Kobayashi Hirokazu
Published: August 2021

We report on Cu/amUiO‐66, a composite made of Cu nanoparticles (NPs) and amorphous [Zr6O4(OH)4(BDC)6] (amUiO‐66, BDC=1,4‐benzenedicarboxylate), and Cu‐ZnO/amUiO‐66 made of Cu‐ZnO nanocomposites and amUiO‐66. Both structures were obtained via a spray‐drying method and characterized using high‐resolution transmission electron microscopy, energy dispersive spectra, powder X‐ray diffraction and extended X‐ray absorption fine structure. The catalytic activity of Cu/amUiO‐66 for CO2 hydrogenation to methanol was 3‐fold that of Cu/crystalline UiO‐66. Moreover, Cu‐ZnO/amUiO‐66 enhanced the methanol production rate by 1.5‐fold compared with Cu/amUiO‐66 and 2.5‐fold compared with γ‐Al2O3‐supported Cu‐ZnO nanocomposites (Cu‐ZnO/γ‐Al2O3) as the representative hydrogenation catalyst. The high catalytic performance was investigated using in situ Fourier transform IR spectra. This is a first report of a catalyst comprising metal NPs and an amorphous metal–organic framework in a gas‐phase reaction.
Tuning the piezoresistive strain‐sensing behavior of poly(vinylidene fluoride)–CNT composites: The role of polymer–CNT interface and composite processing technique
Authors: Kumar G. Sudheer , Patro T. Umasankar
Published: August 2021

In order to understand the role of polymer–carbon nanotube (CNT) interface and composite processing method on strain‐sensing properties, poly(vinylidene fluoride) (PVDF)‐CNT composites have been prepared by melt‐mixing and solution‐casting methods using pristine and acid‐treated CNTs with CNT content of 0.15–4 wt%. The strain rate applied was in the order of s−1. Besides the improved mechanical properties of the composites over pristine PVDF, the piezoresistivity was also profoundly affected by the gentle acid‐treatment of CNTs and the composite processing method leading to tunable strain‐sensing properties. The stability of the strain‐sensors has been further predicted by employing cyclic piezoresistive tests. Interestingly, the pristine CNT composites showed higher strain‐sensitivity likely due to weak interface with polymer and higher initial resistance than the acid‐treated counterparts; while the acid‐treated CNT composites showed better retention of sensing properties under repeated cycles. On the other hand, composites with larger CNT length showed higher strain‐sensitivity than that having shorter CNTs. The temperature dependence of strain‐sensitivity showed a transition from positive to negative temperature coefficient at ~90°C. Finally, the composites subjected to a large number of bending cycles showed excellent performance and stability of strain‐sensing properties, paving the way for development of robust strain‐sensors for structural health monitoring.
Tablet‐assisted objective structured spotter practical examination (TOSSPE): Advantages of an innovative anatomy spotter examination method for medical student assessment
Authors: Polak Katarzyna , Gielecki Jerzy Stanisław , Żurada Anna
Published: August 2021

The affordances of technology‐based assessments, like the objectively structured practical examination, have become an integral part of gross anatomy courses. The Department of Anatomy Faculty of Medicine at the University of Warmia and Mazury developed and introduced an application for tablet devices which has been implemented in student examinations and assessments, called the tablet‐assisted objective structured spotter practical examination. It was created to simplify the educational process and to build a rich learning environment, facilitating deep learning for students through examination and feedback data. The method consists of cadaver stations with traditional corresponding pin spotters in an expanded tablet application. It not only provides instant feedback on various observations of teaching–learning skills but has also positively affected the entire process of education. The method provides an unbiased evaluation of knowledge and understanding of the anatomy course, ensuring objectivity and standardization. The current study was performed on a total of 608 first‐year medical students in Polish and English divisions and focused on the observed advantages since the new method was introduced. Outcomes indicate that after the implementation of the method for both the Polish and English divisions' first‐year medical students, the mean score of examinations significantly increased compared to other teaching–learning methods. The study highlights that students were excited about the implementation of the new method and identified its many benefits. It is recognized that technological development and the digital environment offer a range of opportunities and added value versus traditional assessment activities, methods, and processes.
Utilizing SARS‐CoV‐2 to teach PCR and gel electrophoresis in a pair of asynchronous distant learning laboratory exercises
Authors: Cummings Cristina M.
Published: August 2021

Amidst the COVID‐19 pandemic, many colleges shifted to online learning, creating a need for teaching materials that could be deployed in the online setting. A pair of virtual laboratory exercises with a COVID‐19 theme were created for first year Biology majors to introduce students to the topics of polymerase chain reaction and gel electrophoresis. The exercises were effective in promoting student learning of both topics in an online asynchronous setting, and could easily be adapted for use in other courses or in a synchronous online setting.
Biopsy of cervical lymph node does not impact the survival of nasopharyngeal carcinoma
Authors: Yang Shi‐Ping , Li Ji‐Fang , Zhou Ping , Lian Chen‐Lu , Chen Dan‐Xia , Li Zhao‐Jun , Wu San‐Gang
Published: August 2021

Purpose

The optimal practice regarding cervical lymph node biopsy (CLNB) remains to be defined to provide the best clinical management in nasopharyngeal carcinoma (NPC). This study aimed to investigate the effect of CLNB on the survival of NPC patients.

Methods

Patients diagnosed with NPC from 2004 to 2015 were identified using the Surveillance, Epidemiology, and End Results database. Multivariate logistic regression, Kaplan–Meier method, Cox proportional hazards regression analysis, and propensity score matching (PSM) were used to determine the factors associated with CLNB and prognostic effect of CLNB of NPC.

Results

We included 1903 patients in this study. There were 321 (16.9%) and 1582 (83.1%) patients with and without CLNB, respectively. The percentage of CLNB was 19.4% in 2004 and was decreased to 8.6% in 2015 (p = 0.044). Patients diagnosed in later years (p = 0.008), older age (p < 0.001), Chinese (p = 0.002), advanced tumor stage (p < 0.001), and early nodal stage (p = 0.003) were less likely to receive additional CLNB. In patients who received additional CLNB, the 5‐years NPC‐specific survival (NPCSS) was 83.6%, which was similar to patients without CLNB (80.1%, p = 0.159). In addition, a similar 5‐years NPCSS was found between those receiving biopsy or aspiration of regional lymph node and those receiving lymph node resection (p = 0.584). There were 187 pairs of patients who were completely matched using PSM, the multivariate prognostic analyses indicated that the receipt of CLNB was not associated with an inferior outcome in the PSM cohort (p = 0.349). Similar results were found after stratification by the year of diagnosis, race/ethnicity, and histology.

Conclusion

Additional CLNB is not associated with an inferior survival outcome in NPC. Our study provides a reference for the clinical practice of NPC.
Considering trends of restraints and seclusions by patient race
Authors: Victor Colleen , Brannan Elizabeth , Hunt Jeffrey , Wolff Jennifer
Published: August 2021

Many children are sensitive to the feeling of tags in their clothes, seek out swinging on the swing set at the playground, or refuse to try certain textures of foods.”
Direct oral anticoagulants in patients with atrial fibrillation and bioprosthetic valve replacement: A meta‐analysis
Authors: Lacy Spencer C. , Saint Croix Garly R. , Porter Kadijah , Latib Azeem , Beohar Nirat
Published: August 2021

Objectives

This systematic review and meta‐analysis compares direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) in patients with atrial fibrillation and bioprosthetic valve replacement or repair (BVR).

Background

The optimal anticoagulation therapy for patients with atrial fibrillation and a history of bioprosthetic valve replacement or repair (BVR) is not well understood.

Methods

We performed a systematic literature review to identify clinical studies that compared anticoagulation therapies for patients with atrial fibrillation and BVR. The primary outcomes of stroke, major bleeding, and mortality were reported as random effects risk ratio (RR) with 95% confidence interval. No prior ethical approval was required since all data is public.

Results

Our search yielded 101 potential studies. We included six studies reporting on 1911 patients. There was a lower risk of stroke and major bleeding in patients with atrial fibrillation after BVR treated with DOACs when compared to VKAs with risk ratios of 0.44 (95% CI 0.24–0.82, p < 0.01) and 0.53 (95% CI 0.34–0.83, p < 0.01), respectively. There was no statistically significant difference in mortality between patients with atrial fibrillation after BVR treated with DOACs compared to patients treated with VKAs with a risk ratio of 1.12 (95% CI 0.73–1.74, p = 0.60).

Conclusion

This systematic review and meta‐analysis suggests that DOACs are superior to VKAs with respect to stroke and major bleeding in patients with atrial fibrillation and BVR.