bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies on asymmetric total synthesis of (−)-β-hydrastine via a chiral epoxide ring-opening cascade cyclization strategy
Authors: Li Jihui , Wu Tianxiao , Song Xinjing , Zheng Yang , Meng Jiaxin , Qin Qiaohua , Liu Yongxiang , Zhao Dongmei , Cheng Maosheng
Published: May 2020

Herein, both CF3COOH-catalyzed (86% ee) and KHMDS-catalyzed (78% ee) chiral epoxide ring-opening cascade cyclization to facile and enantioselective synthesis of the core phthalide tetrahydroisoquinoline scaffold of (−)-β-hydrastine are described.
Reconsideration of the conformation of methyl cellulose and hydroxypropyl methyl cellulose ethers in aqueous solution
Authors: Arai Kengo , Horikawa Yoshiki , Shikata Toshiyuki , Iwase Hiroki
Published: May 2020

A rod-like structure with once-folded highly extended hairpin-like conformation is constructed from methyl and hydroxypropyl methyl cellulose ethers in aqueous solution.
Donor–acceptor random regioregular π-conjugated copolymers based on poly(3-hexylthiophene) with unsymmetrical monothienoisoindigo units
Authors: Uegaki Kaoru , Nakabayashi Kazuhiro , Yamamoto Shin-ichi , Koizumi Toshio , Hayashi Shotaro
Published: May 2020

Donor–acceptor π-conjugated random copolymers based on regioregular poly(3-hexylthiophene) with unsymmetrical monothienoisoindigo moieties were obtained by direct arylation polycondensation.
K2S2O8-mediated radical cyclisation of 2-alkynylthioanisoles or -selenoanisoles: a green and regioselective route to 3-nitrobenzothiophenes and benzoselenophenes
Authors: Lu Shi-Chao , Wu Botao , Zhang Shi-Peng , Gong Ya-Ling , Xu Shu
Published: May 2020

This is the first example of highly unstable 2-nitrovinyl radicals for C–S bond formation. The facile route efficiently functionalizes 3-nitrobenzothiophenes and benzoselenophenes, which are difficult to obtain by classical methods.
Mechanistic details of the cobalt-mediated dehydrogenative dimerization of aminoquinoline-directed benzamides
Authors: Xu Li-Ping , Liu Elaine E. L.-N. , Bacsa John , MacBeth Cora E. , Musaev Djamaladdin G.
Published: May 2020

Anionic mechanism is favorable, aryl–aryl C–C coupling is the rate-determining, a CoII and CoIII aminoquinoline-directed benzamide complexes.
Br/Co/N Co-doped porous carbon frameworks with enriched defects for high-performance electrocatalysis
Authors: Dilpazir Sobia , Liu Rongji , Yuan Menglei , Imran Muhammad , Liu Zhanjun , Xie Yongbing , Zhao He , Zhang Guangjin
Published: May 2020

First ZIF-67 derived doped, defect-enriched porous carbon frameworks is reported via a novel self-sacrificing strategy with outstanding performance for ORR, HER and OER and allow the assembly of Zn–air batteries and overall water splitting devices.
A CO2-tolerant SrCo0.8Fe0.15Zr0.05O3−δ cathode for proton-conducting solid oxide fuel cells
Authors: Lv Xiuqing , Chen Huili , Zhou Wei , Li Si-Dian , Shao Zongping
Published: May 2020

5 mol% zirconium was introduced into SrCo0.8Fe0.2O3−δ (SCF) to improve its structural stability and CO2 tolerance. Proton-conducting solid oxide fuel cells (H+-SOFCs) with SCFZ material as a cathode showed a high output and durability.
Light-gated cation-selective transport in metal–organic framework membranes
Authors: Liang Hong-Qing , Guo Yi , Peng Xinsheng , Chen Banglin
Published: May 2020

This work reported the fabrication of composite ZIF-8 membranes that can selectively separate Li+from other cations and regulate Li+conduction by light simultaneously.
In situsynchrotron pair distribution function analysis to monitor synthetic pathways under electromagnetic excitation
Authors: Nakamura Nathan , Su Laisuo , Bai Jianming , Ghose Sanjit , Reeja-Jayan B.
Published: May 2020

In situpair distribution function analysis reveals that electromagnetic radiation exposure during SnO2nanoparticle growth alters local atomic structure and the synthetic pathway compared to conventional hydrothermal synthesis routes.
Correction: Iron-based clusters embedded in nitrogen doped activated carbon catalysts with superior cathodic activity in microbial fuel cells
Authors: Zhang Xiaoyuan , Guo Xingguo , Wang Qiuying , Zhang Rufan , Xu Ting , Liang Peng , Huang Xia
Published: May 2020

Correction for ‘Iron-based clusters embedded in nitrogen doped activated carbon catalysts with superior cathodic activity in microbial fuel cells’ by Xiaoyuan Zhang et al., J. Mater. Chem. A, 2020, DOI: 10.1039/C9TA10797E.
Responsive polymers for medical diagnostics
Authors: Appavoo Divambal , Park Sung Young , Zhai Lei
Published: May 2020

Stimulus-responsive polymers have been used in improving the efficacy of medical diagnostics through different approaches including enhancing the contrast in imaging techniques and promoting the molecular recognition in diagnostic assays.
Doping of silicon by phosphorus end-terminated polymers: drive-in and activation of dopants
Authors: Perego Michele , Caruso Francesco , Seguini Gabriele , Arduca Elisa , Mantovan Roberto , Sparnacci Katia , Laus Michele
Published: May 2020

An effective doping technology for precise control of P atom injection and activation into a semiconductor substrate is presented.
Specific features of the electronic and crystal structure of CuxZrSe2 (0 < x ≤ 0.3)
Authors: Shkvarin A. S. , Merentsov A. I. , Yarmoshenko Yu. M. , Postnikov M. S. , Shkvarina E. G. , Mostovshchikova E. V. , Titov A. A. , Pis I. , Bondino F. , Uporov S. A. , Melchakov S. Yu. , Titov A. N.
Published: May 2020

Crystal and electronic structure, optical absorption and transmission spectra, temperature dependences of conductivity and magnetic susceptibility were studied for copper intercalated ZrSe2 in the copper concentration range of 0 ≤ x ≤ 0.3.
Per2 attenuates LPS-induced chondrocyte injury through the PTEN/PI3K/Akt signalling pathway
Authors: Zhao Yu , Ma Ding , Dong Bingchen , Li Ming
Published: May 2020

This research aimed to explore the role of period circadian clock 2 (Per2) in the evolution of osteoarthritis (OA) and the relevant mechanisms. Per2 messenger RNA (mRNA) and protein levels were markedly reduced in NHAC-kn cells treated with 5 µg/ml lipopolysaccharide (LPS) for 12 h. Then, pcDNA3.1-Per2 and si-Per2 were recruited to boost and reduce the expression of Per2, respectively. MTT assay, apoptosis analysis and enzyme-linked immunosorbent assay (ELISA) results showed that Per2 increased cell proliferation, while inhibited apoptosis and inflammation. Furthermore, the PTEN/PI3K/Akt signalling pathway was activated by Per2 overexpression; the CO-IP data confirmed that Per2 specifically bound to PTEN. Through employing IGF-1, a PI3K activator, we determined that Per2-mediated inflammation response in LPS-stimulated NHAC-kn cells through the PTEN/PI3K/Akt signalling pathway. In summary, the present study indicates that Per2 may serve as a novel therapeutic target through activating the PTEN/PI3K/Akt signalling pathway.
Variational Bayesian adaptive high‐degree cubature Huber‐based filter for vision‐aided inertial navigation on asteroid missions
Authors: Su Bingzhi , Mu Rongjun , Long Teng , Li Yuntian , Cui Naigang
Published: May 2020

Vision‐aided inertial navigation (VAIN) is a prospective technique for determining the pose of the spacecraft during asteroid missions. The VAIN system can fuse the inertial and visual data by employing the high‐degree cubature Kalman filter (HCKF) because it can accurately handle non‐linear problems. However, the visual measurements can be corrupted by non‐Gaussian noise with unknown time‐varying covariance, resulting in severe degradation of the HCKF. To improve the navigational accuracy of the spacecraft in these situations, the authors propose a novel adaptive robust HCKF known as variational Bayesian (VB) adaptive high‐degree cubature Huber‐based filter (VB‐AHCHF). In the novel algorithm, the fifth‐degree cubature rule and VB theory are combined to estimate the state and track the non‐stationary statistical characteristics of the measurement noise. In addition, utilising the M‐estimation, which is defined as the Huber technique, it modifies the update step of the formal Bayesian filtering. Therefore, the VB‐AHCHF can exhibit adaptability and robustness to the covariance uncertainty and non‐Gaussianity of the measurement noise. Their simulation results show that the estimation accuracy of VB‐AHCHF, as well as its adaptability and robustness, is superior to all state‐of‐the‐art algorithms, e.g. HCKF, high‐degree cubature Huber‐based filter, and the VB adaptive HCKF.
Xiaomi Mi 8 smartphone GNSS data quality analysis and single‐frequency RTK positioning performance evaluation
Authors: Sun Wei , Li Yuying , Duan Shunli
Published: May 2020

In this study, the authors mainly explore the relationship between the data quality of smartphones equipped with global navigation satellite system (GNSS) modules and the accuracy and reliability of single‐frequency real‐time kinematic (RTK) positioning. Specifically, the visible satellite number, code minus carrier and the signal‐to‐noise ratio of the GNSS raw observations were evaluated through static experiments and dynamic experiments, and the performance difference between single‐frequency global positioning system (GPS) RTK and single‐frequency BeiDou Navigation Satellite System (BDS) RTK positioning was compared and analysed. In the static experiment, the average values of visible satellites of BDS and GPS in Xiaomi Mi 8 smartphone are 7.4 and 8.4, respectively. The average code minus carrier error of GPS is 5.234 m, the BDS is 5.518 m, and the average signal‐to‐noise ratio of GPS is ∼29.092 dB Hz and the BDS is ∼28.718 dB Hz. The data quality of the dynamic experiment is similar to the static experimental result. The positioning accuracy obtained by the static experiment from the single‐frequency GPS RTK and single‐frequency BDS RTK in the east/north/up (E/N/U) directions is 0.146/0.555/0.464 m and 0.843/0.287/0.317 m, respectively. The instability of BDS‐locked satellite in dynamic experiment results the positioning accuracy of BDS RTK is lower than that of GPS.
Migration of uranium in the system soil-plant (model experiments)
Authors: Bondareva Lydia
Published: May 2020

Migration of uranium-238 in the system soil-plant at an example of a flower crop, marigold (Tagetes erecta) was studied. The above-mentioned components were used to treat the soil after planting. Using the method of sequential fractionation, soil extracts were obtained, with the content of uranium amounting to ~2 %. Upon the introduction of oil and uranium into the experimental system, the portion of uranium increased in the root parts of the plants (µg/sample): from 0.81 to 9.43, and in the above-ground parts (µg/sample): from 0.78 to 17.1; with the introduction of the oilfield water there was the increased extraction of uranium which had earlier been present in the soil while the uranium content in the root and above-ground parts of the plants in the systems containing oil, oilfield water was considerably higher than in the control system (from 1.17 to 6.73 µg as compared with 0.78 in the above-ground parts of the plants and from 9.92 to 12.87 as compared with 0.81 µg in the root parts). Upon the introduction of uranium combined with oil the radionuclide content was significantly different from the content in the root parts (17.1 in the above-ground parts and 9.43 µg in the root parts).
Migration of cyantraniliprole in fractured soils: calibration of pesticide leaching model by using experimental data
Authors: Belik Aleksandra , Kokoreva Anna , Kolupaeva Victoria
Published: May 2020

The phenomenon of preferential migration of substances can increase the risk of pesticides. In the first year of the experiment, in 7 days after application cyantraniliprole penetrated to a depth of 25 cm in agrosoddy-podzolic soil. In the next year on the 7th day after application the pesticide was detected at a depth of 15 cm. The pesticide migrated deeper than the unconfigured PERL model took into account. The calibration of the PERL model by using experimental data (soil experimental support) allowed to reduce the error of prediction. The obtained data can be used to create new standard soil and climate scenarios for pesticide leaching models.
Geochemical features of soils from the Mid-Ural ore deposit
Authors: Dziuba Ekaterina , Andreev Dmitriy , Buzmakov Sergey , Khotyanovskaya Yuliya
Published: May 2020

This paper deals with the contemporary state of soil cover around the Mid-Ural iron ore deposit, focusing on geochemical features. Sample plots were laid based on the technogenic impact in the study area. Soil samples were taken in the zone of the iron ore deposit, in the zones of overburden and gold mining waste dumps influence, and in the rock blasting site. A total of 64 sample plots were laid. Soil samples were sampled incrementally by an envelope method from a depth of 0.00–0.03 m. Soil texture, physicochemical features, and total heavy metal content (V, Mn, Ni, Cu, Zn, As, Cd, and Pb) were defined for the soil samples. As a result, the evaluation of heavy metal soil pollution under the influence of iron ore deposit mining is given. Chemical contamination of soil was assessed by a cumulative chemical contamination index. Geochemical series of elements formed under the influence of iron ore deposit mining, as well as overburden and gold mining are given. Here, geochemical patterns of heavy metal distribution in the soil of iron ore deposit and under the gold mining influence are considered. The analysis of gold mining influence on the elementary composition of soil revealed the anomalous content of Mn and Ni.
Accumulation of heavy metals in aquatic vegetation of the Barguzin River
Authors: Shiretorova Valentina G. , Zhigzhitzhapova Svetlava V. , Dylenova Elena P. , Radnaeva Larisa D.
Published: May 2020

This study is devoted to the analysis of the distribution of heavy metals in the aquatic system of the Barguzin River. This is one of the largest rivers of the Baikal lake system. The element composition of the aerial scion of Potamogeton pectinatus L. (syn. Stukenia pectinata (L.) Borner), Potamogeton perfoliatus L., Hippuris vulgaris L. and Nymphoides peltata (S.G. Gmelin) O. Kuntze of the Barguzin River is studied in this research. One of the main results of the study is the establishment of the following sequence of the accumulation of metals in aquatic plants: Mn > Fe > Сu (Zn) > Сr > Ni > Сo > Pb > Cd > Hg. Hippuris vulgaris L. contains the highest concentration of the studied metals. Thus, this research provides one of the important steps for the development of regional environmental standards and environmental risk assessments.
Ecotoxicological hazard assessment of deicing chemicals for higher plants
Authors: Fedorchenko M.D. , Mikhaylichenko K. Yu. , Ushakova O.V. , Adarchenko I.A.
Published: May 2020

The article presents data on ecotoxicological hazard assessment of different types of deicing chemicals for higher plants. The assessment was carried out according to a specifically developed rapid test on oats seeds. The phytoeffect was determined by comparing the lengths of the seedling roots placed in a solution of deicing chemicals and was calculated by the effect size of root growth inhibition comparing with proof sample. The safest composition of deicing chemicals was determined.
Content of heavy metals in Haplic Chernozem under conditions of agrogenesis
Authors: Medvedeva Anna , Buryukova Olga , Kucherenko Alexey , Ilchenko Yaroslav , Chaplygin Victor , Rajput Vishnu D. , Kizilkaya Ridvan
Published: May 2020

The paper presents the results of a long-term study on the content and distribution of heavy metals in Haplic Chernozem of agrocenoses in southern zone of Rostov Region. The impact of various agricultural technologies traditional (using moldboard ploughing) and resource-saving (minimum and No-till) on accumulation and mobility of Pb, Zn, Cu in Haplic Chernozem in winter wheat cultivation is considered. The total content of Pb, Zn, Cu in the winter wheat areas corresponds to the background level and does not exceed permissible concentrations. Low mobility of elements (Pb 2.0-3.0%; Zn and Cu up to 1.0% as a percentage of their total forms) is a regional soil feature. In addition, the low availability of Zn and Cu in soils is due to their removal with the crops in the absence of micronutrient fertilizer replenishment. The significant role of soil organic matter in the accumulation of both total and mobile forms of heavy metals in soil has been confirmed. The intensity of the cultivation methods used has a significant effect on the total content of Zn, Cu and on the mobility of Pb, Zn, Cu in Haplic Chernozem.
Possibilities of using sentinel-2 satellite data to estimate crop cover and LAI of winter wheat at different stages of development
Authors: Mullo Feddy , Prudnikova Elena
Published: May 2020

The study was conducted on a test plot located in the Yasnogorodsky district of the Tula Region; With a camera with fisheye lens photographs were taken at different points of the plot, each point with a geographical reference. Subsequently, the possible relationship between the information extracted from the classification of the photographs using the CAN-EYE software (LAI, percentage of vegetation) and the vegetation indices (Ratio, NDVI, SAVI and EVI) calculated with spectral values obtained from the different channels of Sentinel-2 (B2, B3, B4, B5, B6, B7, B8, B8a) were evaluated. Finally, best regression models obtained for each phase of the winter wheat development were used to create the maps of LAI and percentage of vegetation. According to our results, Sentinel-2 can be successfully used to map LAI in the studied region at the shooting stage of winter wheat development with accuracy of 85 %. At other stages and for percentage of vegetation the accuracy of the models was below 50 %.
Dewatering as a primary treatment of faecal sludge in individual residential sector (a technologies review)
Authors: Basamykina Alena , Kharlamova Marianna , Mada Sharon Yeukai
Published: May 2020

Dewatering of faecal sludge (FS) is the most efficient method of pretreatment of bioorganic human waste for minimizing the faecal sludge volume. This process may be considered as one of management tool in service chain of Faecal Sludge Management (FSM). For this purpose technological features of methods, the advantages, disadvantages and possibilities of the use have been analysed. The article provides a review of the most efficiently methods of faecal sludge dewatering generated in the individual residential sector (unplanted drying beds, planted drying beds, solar drying, mechanical dewatering, geotubes) and their analysis in order to select the best available technology in accordance with the selection criteria. We used the analytic hierarchy process to determine the most multi-operated and effective processing method of faecal sludge dewatering. The final ranking for each dewatering technology was based on the global weights of 10 criteria (dewatering efficiency, operation time, process automation, required space, climate dependent, capital expenditures, operating costs, energy efficiency and environmental impact). The results identify dewatering method with the highest priority result based on priority eigenvalues of criteria.
Evaluation of the biological activity of meadow chernozem soils after the application of biochars with different pyrolysis temperatures in a model experiment
Authors: Zinchenko Vladislav , Gorovtsov Andrey , Sushkova Svetlana , Antonenko Svetlana , Fedorenko Elena , Pogonyshev Pavel , Barakhov Anatoly
Published: May 2020

The paper aims to study the effect of fresh and aged biochar with different pyrolysis temperatures and metal resistant bacteria on the numbers of microorganisms and the dehydrogenase activity of meadow chernozem soils. The use of fresh biochar leads to an increase in the number of soil bacteria and suppression of dehydrogenase activity; after ageing biochar by incubation in the soil, dehydrogenase activity increases significantly.
Economic efficiency of the water monitoring system in Nigeria
Authors: Nwankwo Nnabueze Kalu , Zakirova Yulia
Published: May 2020

Currently, many areas in Nigeria face strong water stress, and to reduce the pressure exerted on water, making water a reusable ecosystem service is essential. Economic efficiency of a water monitoring system can involve having a program to influence and manage water resources and the environment based on the utilization of modern information technologies and techniques. This article aims at demonstrating the importance of Economic efficiency of a water monitoring system, cases and deaths from water-related diseases by decade. A significant factor of managing water safety is understanding water availability, demand, utilization, how it acts in response to change, climate and pressures. Comprehensive understanding of a water system correctly and deeply depends on professionalism, monitoring, documentation and reporting of water system parameters. Human health risk assessment model was applied to estimate cases and deaths from water-related diseases.
The role of specially protected natural areas in solving environmental problems of the Russian arctic (using the example of Vaygach Island)
Authors: Aleinikova Anna , Byashkin Maksim , Gaivoron Tatiana , Mainasheva Galina , Marsheva Natalia
Published: May 2020

The Russian Arctic is a unified physical and geographical system of land and sea areas of Northern Eurasia, within which unique natural and historical and cultural objects are concentrated. The system of specially protected natural areas of the Russian Arctic preserves vulnerable arctic, tundra landscapes under conditions of various anthropogenic activities. In the face of modern climate change, monitoring of the transformation of the Arctic landscapes in specially protected natural areas is important. The landscape map compiled as a result of our own field and office studies shows 26 natural complexes. The most interesting for ecological tourism is the north-western part of the island. .By the example of Vaygach Island, the natural and historical-cultural possibilities of organizing a protected area, including the solution of environmental problems, are considered.
The study of the zoobenthos of the Tsraudon river basin (the Terek river basin)
Authors: Dzhioeva Ia E. , Cherchesova Susanna K. , Navatorov Oleg A. , Lamarton Sofia F.
Published: May 2020

The paper presents data on the species composition and distribution of zoobenthos in the Tsraudon river basin, obtained during the 2017-2019 research. In total, 4 classes of invertebrates (Gastropoda, Crustacea, Hydracarina, Insecta) are found in the benthic structure. The class Insecta has the greatest species diversity. All types of insects in our collections are represented by lithophilic, oligosaprobic fauna. Significant differences in the composition of the fauna of the Tsraudon river creeks and tributary streams have been identified. 7 families of the order Trichoptera are registered in streams, and 4 families in the river. It is established that the streamlets of the family Hydroptilidae do not occur in streams, the distribution boundary of the streamlets of Hydropsyche angustipennis (Hydropsychidae) is concentrated in the mountain-forest zone. The hydrological features of the studied watercourses are also revealed.
Impact of Urban Environment on Students’ Daily Rhythms and Sleep Patterns
Authors: Piven Elena A. , Piven Nikolay P. , Bushuev Nikolay N.
Published: May 2020

This article presents the results of a research of the sleep patterns of 200 students living in dormitories in Moscow. The average duration of night sleep in the surveyed group was 6h 37min. The proportion of students satisfied with the duration of night sleep was 36.5 %. Daily activity rhythms, in particular, the going to sleep and awakening time at the same time, are compiled by 47.5 % of the surveyed students. 86.5 % of students go to bed after midnight. The most late going to sleep time is observed among students of the 1st and 4th years. 37 % of students suffer from insomnia, which is most often caused by stress and work in extracurricular time. It was found that the best indicators of well-being and learning ability were observed at night sleep duration from 6 to 8 hours. When the duration of night sleep is less than 6 hours, there was a deterioration in the state of students’ health, wellbeing and learning ability. It was revealed that 92.2 % of students who fall ill three or more times a year have a night sleep duration of less than 6 hours.
On the implementation of the state environmental policy in law-making and law-enforcement activities in Russia
Authors: Mukhlynina Maria
Published: May 2020

The article considers a number of issues of the state environmental policy of the Russian Federation based on the analysis of new laws of the Russian legislation and the current socio-economic situation in the country. The author notes the state strategic documents and programs developed by the Ministry of natural resources of the Russian Federation, presents some data on environmental legislation in the country, and makes judgments that a successful environmental policy is possible only with an integrated approach to the implementation of environmental legislation.
Deep vein thrombosis after “Tennis Leg” injury: A clinical case
Authors: Gonell Alfonso Calvo
Published: May 2020

Background “Tennis leg” is a common lesion in sports with quick accelerations and stops, consisting of an injury to the fascia joining the soleus muscle with the medial gastrocnemius. In these cases, a differential diagnosis must be performed, considering possible complications such as a deep vein thrombosis (DVT) of the veins of the deep musculature of the lower leg. The aim of this clinical case is to alert professionals regarding possible complications of these injuries and to train professionals to detect a possible vascular problem.

Case Description A 42 year old male who attends a physical therapy consultation 24 hours after suffering a “muscle pull” in the gastrocnemius. After a medical diagnosis of tennis leg he received appropriate standard regulated physical therapy treatment procedures. A follow-up ultrasound exam was performed eight days after the injury and at 14 days after a worsening of symptoms, at which point a vascular alteration was detected which was diagnosed and treated as DVT.

Results The patient came for consultation and we observed a vascular alteration and therefore we referred the person to the emergency room, where he was diagnosed with DVT.

Discussion DVT is a possible complication of gastrocnemius injuries. The present case describes a clinical presentation of DVT after 14 days evolution. It is essential to evaluate and reevaluate the clinical condition of the patient with all the diagnostic tools possible to detect possible red flags.

Conclusion Ultrasound is an essential tool for the detection of possible complications after a musculoskeletal injury.
A Systematic Review of Closure Techniques in Lateral Skull Base Tumor Surgery
Authors: Malone Alexander , Randall Michael , Boyev K. Paul
Published: May 2020

Introduction Tumors of the lateral skull base often require collaboration between neurosurgeons and neurotologists for the surgical approach. The three main transosseous surgical approaches are retrosigmoid (RS), translabyrinthine (TL), and middle fossa (MF). The literature reflects a relative paucity regarding the various closure techniques for these approaches and the postoperative complications. We have performed a systematic review comparing closure techniques from each approach.

Methods A systematic review was performed using Ovid MEDLINE (1990–2016) on closure technique and postoperative complications for patients undergoing lateral skull base surgery via the TL, RS, or MF approach. Studies were included if they contained at least 10 patients, described their closure technique, and provided data on postoperative complications.

Results A total of 1,403 studies were reviewed. Of these, 53 studies met inclusion criteria yielding a total of 10,466 subjects in this analysis. The average rate of cerebrospinal fluid leak was 5.3% in the TL approach, 9% in the RS approach, and 6.2% in the MF approach. There was no significant effect of various closure techniques on postoperative wound complications in the MF approach. Multiple factors were identified which affected postoperative wound complication in the RS and TL approaches.

Conclusion There are a plethora of closure techniques for lateral skull base surgery. Several techniques were identified in this review that may affect the postoperative wound complication rates in lateral skull base surgery.
Copper-Catalyzed Asymmetric Intermolecular N-Monoarylation of Unprotected Sulfonamides via Desymmetrization of Diaryliodonium Salts at Room Temperature
Authors: Jin Xiao , Yu Xiu-Ling , Yang Wen-Qiang , Li Yan-Li , Zhang Chun , Wang Zhen , Zhang Hui-Zhen
Published: May 2020

A copper-catalyzed asymmetric intermolecular N-monoarylation of weakly nucleophilic sulfonamide by desymmetrization of cyclic diaryliodonium salts has been developed. Chiral copper(II)–diamine ligand complexes catalyzed this intermolecular asymmetric aryl C–N cross-coupling reaction effectively at room temperature to afford a series of N-monoarylsulfonamides in good to excellent yields and enantioselectivities.
Treatment of Trigeminal Neuralgia with “Microvascular Decompression Plus” Technique
Authors: Liu Ming-Xing , Zhong Jun , Xia Lei , Dou Ning-Ning , Shi Juanhong
Published: May 2020

Objective Although microvascular decompression (MVD) has been widely accepted as an effective treatment of trigeminal neuralgia (TN), some patients have not been cured. To improve the postoperative outcome, the surgical procedure should be further refined.

Design This is a retrospective study.

Setting Present study conducted at a cranial nerve disorder center.

Participants Clinical data were collected from patients with TN who had undergone surgery in our center, including 685 who had undergone traditional MVD and 576 who had undergone the “MVD plus” procedure, in which any vessel attached to the trigeminal nerve was freed away (“nerve-combing”), which was followed by intraoperative neurolysis.

Main Outcome Measures Postoperative outcomes and complications in the two groups were compared.

Results Among patients who underwent traditional MVD, the rates of immediate relief and 1-year relief were 89.9 and 86.9%, respectively; among patients who underwent MVD plus group, these rates were 95.1 and 94.6%, respectively (p = 0.05). Patients who underwent MVD plus initially exhibited a higher rate of facial numbness (p < 0.05), but this finding decreased over time and reached the same level as that in the traditional MVD group within 3 months (p > 0.05).

Conclusion Sufficient MVD with nerve-combing for the treatment of TN may produce a high rate of cure with less recurrence.
The Relationship between Status at Presentation and Outcomes among Pregnant Women with COVID-19
Authors: London Viktoriya , McLaren Rodney , Atallah Fouad , Cepeda Catherine , McCalla Sandra , Fisher Nelli , Stein Janet L. , Haberman Shoshana , Minkoff Howard
Published: May 2020

Objective This study was aimed to compare maternal and pregnancy outcomes of symptomatic and asymptomatic pregnant women with novel coronavirus disease 2019 (COVID-19).

Study Design This is a retrospective cohort study of pregnant women with COVID-19. Pregnant women were divided into two groups based on status at admission, symptomatic or asymptomatic. All testing was done by nasopharyngeal swab using polymerase chain reaction (PCR) for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Initially, nasopharyngeal testing was performed only on women with a positive screen (symptoms or exposure) but subsequently, testing was universally performed on all women admitted to labor and delivery. Chi-square and Wilcoxon's rank-sum tests were used to compare outcomes between groups.

Results Eighty-one patients were tested because of a positive screen (symptoms [n = 60] or exposure only [n = 21]) and 75 patients were universally tested (all asymptomatic). In total, there were 46 symptomatic women and 22 asymptomatic women (tested based on exposure only [n = 12] or as part of universal screening [n = 10]) with confirmed COVID-19. Of symptomatic women (n = 46), 27.3% had preterm delivery and 26.1% needed respiratory support while none of the asymptomatic women (n = 22) had preterm delivery or need of respiratory support (p = 0.007 and 0.01, respectively).

Conclusion Pregnant women who presented with COVID19-related symptoms and subsequently tested positive for COVID-19 have a higher rate of preterm delivery and need for respiratory support than asymptomatic pregnant women. It is important to be particularly rigorous in caring for COVID-19 infected pregnant women who present with symptoms.

Key Points
Time-resolved measurement of space-charge evolution in dielectric films or slabs by means of repeatable laser-induced pressure pulses
Authors: Spelzhausen S. , Ionian M.-R. , Gerhard R. , Plath R.
Published: May 2020

A new variant of the Laser-Induced Pressure-Pulse (LIPP) method for repeatable, time-resolved space-charge profile measurements is proposed and demonstrated. Automated deposition of a fresh laser-target film before each illumination leads to good repeatability of the LIPP and thus allows for the detection of time-resolved changes in the space-charge distribution over many hours. We describe and discuss the experimental setup and its features, compare the repeatability of the LIPP measurements on the same sample without and with re-preparation of the test cell, and present the time-resolved evolution of the space-charge profile in a two-layer arrangement of a silicone-grease and a silicone-elastomer film as an example. Finally, the temperature dependence of the space-charge evolution during polarization under high voltage and during depolarization in short circuit is shown. Possible uses and future developments of the new LIPP approach are also discussed.
Open-boundary Hamiltonian adaptive resolution. From grand canonical to non-equilibrium molecular dynamics simulations
Authors: Heidari Maziar , Kremer Kurt , Golestanian Ramin , Potestio Raffaello , Cortes-Huerto Robinson
Published: May 2020

We propose an open-boundary molecular dynamics method in which an atomistic system is in contact with an infinite particle reservoir at constant temperature, volume, and chemical potential. In practice, following the Hamiltonian adaptive resolution strategy, the system is partitioned into a domain of interest and a reservoir of non-interacting, ideal gas particles. An external potential, applied only in the interfacial region, balances the excess chemical potential of the system. To ensure that the size of the reservoir is infinite, we introduce a particle insertion/deletion algorithm to control the density in the ideal gas region. We show that it is possible to study non-equilibrium phenomena with this open-boundary molecular dynamics method. To this aim, we consider a prototypical confined liquid under the influence of an external constant density gradient. The resulting pressure-driven flow across the atomistic system exhibits a velocity profile consistent with the corresponding solution of the Navier–Stokes equation. This method conserves, on average, linear momentum and closely resembles experimental conditions. Moreover, it can be used to study various direct and indirect out-of-equilibrium conditions in complex molecular systems.
Effect of dissolved salt on the anomalies of water at negative pressure
Authors: Zaragoza Alberto , Tripathi Chandra Shekhar Pati , Gonzalez Miguel A. , Abascal José Luis F. , Caupin Frédéric , Valeriani Chantal
Published: May 2020

Adding salt to water at ambient pressure affects its thermodynamic properties. At low salt concentration, anomalies such as the density maximum are shifted to lower temperature, while at large enough salt concentration, they cannot be observed any more. Here, we investigate the effect of salt on an anomaly recently observed in pure water at negative pressure: the existence of a sound velocity minimum along isochores. We compare experiments and simulations for an aqueous solution of sodium chloride with molality around 1.2 mol kg−1, reaching pressures beyond −100 MPa. We also discuss the origin of the minima in the sound velocity and emphasize the importance of the relative position of the temperatures of sound velocity and density anomalies.
Compact and efficient elastocaloric heat pumps—Is there a path forward?
Authors: Slaughter Julie , Czernuszewicz Agata , Griffith Lucas , Pecharsky Vitalij
Published: May 2020

Elastocaloric cooling holds promise for energy-efficient heat pumping near room temperature with low environmental impact. Its adoption is, however, impeded by disproportionally large sizes of actuators compared with the active material volume. Taking magnetocaloric cooling as the baseline, the value of no more than 10:1 actuator volume to active material volume should lead to both size- and cost-effective solutions that may potentially be competitive with vapor-compression devices. With the goal to establish performance metrics that can lead to informed actuator selection for specific regenerator requirements, we analyze a wide range of elastocaloric materials and actuator technologies to find the best matches. We find that actuation with magnetic shape memory alloys meets all requirements; however, this technology is currently in early developmental stages and such actuators are not widely commercially available. Another promising and easily accessible option is standard rotary electric motors in combination with rotary-to-linear transduction mechanisms. A theoretical analysis of two case studies of elastocaloric systems using rotary electric motors with a Scotch yoke mechanism demonstrates the usefulness of our approach. Actuator requirements are based on two different regenerator configurations: one starting from zero strain without any mechanical energy recovery and another with 2% pre-strain and mechanical energy recovery to reduce the power and torque required from the motor. Our results indicate that the 10:1 target actuator to active material volume ratio can be met and feasibly lowered further, demonstrating that the proposed method for selecting actuators makes compact and efficient elastocaloric systems possible.
Hierarchical metastructures with programmable stiffness and zero Poisson’s ratio
Authors: Jiao Pengcheng
Published: May 2020

Exploring performance by structural design and assembly strategies, mechanical metamaterials have recently attracted attention due to their prominent mechanical properties compared with traditional structures. Structural instability (e.g., buckling) has been deployed to form architected structures for multifunctional applications. Here, we report novel types of hierarchical metastructures composed of postbuckled elements, which have programmable mechanical characteristics under tension and compression. Simply tuning the geometries of the postbuckling elements, the presented metastructures have promising mechanical response (i.e., programmable tensile and compressive stiffnesses, zero Poisson’s ratio, and recovery from large deformation). The reported hierarchical metastructures were fabricated and assembled using a 3D printing technique. Experiments were conducted and the results were validated with the analytical and numerical models with satisfactory agreement. The programmability is investigated with respect to the geometries of the bi-constrained beams. In favor of the buckling-induced, elastic deformation of the bilaterally constrained elements, the reported metastructures can be deployed for multipurpose applications, such as energy dissipation through the repeatable deformation-recovery process or damage detection based on the variation of postbuckling mode configuration.
Wafer-scale heterogeneous integration InP on trenched Si with a bubble-free interface
Authors: Lin Jiajie , You Tiangui , Jin Tingting , Liang Hao , Wan Wenjian , Huang Hao , Zhou Min , Mu Fengwen , Yan Youquan , Huang Kai , Zhao Xiaomeng , Zhang Jiaxiang , Wang Shumin , Gao Peng , Ou Xin
Published: May 2020

Heterogeneous integration of compound semiconductors on a Si platform leads to advanced device applications in the field of Si photonics and high frequency electronics. However, the unavoidable bubbles formed at the bonding interface are detrimental for achieving a high yield of dissimilar semiconductor integration by the direct wafer bonding technology. In this work, lateral outgassing surface trenches (LOTs) are introduced to efficiently inhibit the bubbles. It is found that the chemical reactions in InP–Si bonding are similar to those in Si–Si bonding, and the generated gas can escape via the LOTs. The outgassing efficiency is dominated by LOTs’ spacing, and moreover, the relationship between bubble formation and the LOT’s structure is well described by a thermodynamic model. With the method explored in this work, a 2-in. bubble-free crystalline InP thin film integrated on the Si substrate with LOTs is obtained by the ion-slicing and wafer bonding technology. The quantum well active region grown on this Si-based InP film shows a superior photoemission efficiency, and it is found to be 65% as compared to its bulk counterpart.
Measurement of the momentum accommodation coefficient for the interactions between electric thruster plume and a solid surface
Authors: Liu Lihui , Cai Guobiao , Zheng Hongru , Shang Shengfei , He Bijiao
Published: May 2020

When the plume of electric thrusters, which is the plasma flow, collides with a surface of spacecraft, a force is exerted on the surface, causing the spacecraft to be flipped or deorbited. The force is generated by the plasma–surface interactions, which can be described using the momentum accommodation coefficient (MAC). As far as we know, only the MAC where the plasma flow is assumed as the combination of singly charged ions, electrons, and neutral gases has been studied. However, the plasma flow of electric thrusters contains not only singly charged ions but also multiply charged ions. In addition, the plasma–surface interactions are usually accompanied by the charged-exchange (CEX), sputtering, and plasma sheath, all of which influence the momentum transfer. Therefore, in this study, the MAC in plasma–surface interactions is developed by quantifying the effect of the multiply charged ions, CEX, sputtering, and plasma sheath. The formulas of the normal momentum accommodation coefficient (NMAC) and tangential momentum accommodation coefficient are derived, respectively, and then, a measurement method of the MAC is proposed with the derived formulas. Moreover, a NMAC was measured when the plasma flow, which was jetted by an ion thruster with an acceleration voltage of 1000 V, impacted an immersed surface vertically, and the measured NMAC is approximated as 1.0. The effect degree and mechanism of the aforementioned factors on the MAC were discussed. Finally, the force exerted on the immersed surface was simulated using the measured NMAC, and the results are in good agreement with the experimental results.
Tuning the temperature-induced local-dipole coupling in (1−x)Na0.5Bi0.5TiO3-xBaTiO3 via electric field
Authors: de la Flor G. , Mihailova B.
Published: May 2020

In situ temperature-dependent Raman-scattering experiments under an external dc electric field E have been performed on (1−x)Na0.5Bi0.5TiO3-xBaTiO3 single crystals with x ranging from 0.013 to 0.074 in order to gain further insights into the atomistic mechanism of polar coupling in lead-free perovskite-type (ABO3) ferroelectric solid solutions near the morphotropic phase boundary (MPB). The polarized Raman spectra collected between 770 and 100 K under an E applied along the pseudocubic [100] direction were analyzed in terms of hard-mode spectroscopy. The results reveal enhanced coupling between the polar displacements of the A-site Bi3+ and B-site Ti4+ cations for x=0.048∼xMPB when a moderate E[100] field is applied, a local-scale phenomenon that might be responsible for the known drift of the MPB under external stimuli. In addition, for all studied compounds, the characteristic temperatures TA−A′ and TA−A′′, preceding the macroscopic Tm and Td and related to mesoscopic-scale antiferroelectric and ferroelectric coupling processes within the A-site-cation subsystem in a zero field, merge into one even under a weak electric field, suggesting that the structural state between the paraelectric and ferroelectric zones in the x-T diagram is weak ferrielectric.
Analysis of melting and solidification processes in the phase-change device of an energy storage interconnected heat pump system
Authors: Gao Xiang , Zhang Wenke , Fang Zhaohong , Hou Xing , Zhang Xin
Published: May 2020

In this paper, an energy storage interconnected heat pump system is proposed. Numerical simulation is performed to investigate the melting and solidification processes of paraffin in a spherical heat storage unit. The influences of the spherical wall temperature, spherical heat storage unit size, and initial temperature of the phase-change material during the melting process, as well as the influence of the spherical wall temperature on the solidification process, were analyzed. The results indicated that the size of the spherical heat storage unit had the most dominant influence on the melting and solidification processes. The overall melting time was less than the overall solidification time at the same temperature difference. In the melting process, convective heat transfer invariably occurs between the liquid phase and the spherical wall, which accelerates the melting process.
Optimizing the piezoelectric vibration of Pb(Mg1/3Nb2/3)O3-0.25PbTiO3 single crystal by alternating current polarization for ultrasonic transducer
Authors: Xu Jialin , Zhang Zhang , Liu Sixing , Xiao Junjie , Yue Qingwen , Deng Hao , Wang Xian , Lin Di , Wang Feifei , Zhang Rui , Li Xiaobing , Luo Haosu
Published: May 2020

Alternate current poling (ACP) is an effective method to enhance the piezoelectric performance of Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) single crystals dramatically. For their application in piezoelectric transducers for medical imaging, the beam mode vibration of PMN-0.25PT single crystal resonators after ACP was investigated by combining experimental impedance measurements and finite element simulation. The complete material coefficients of PMN-0.25PT single crystals were obtained by using pulse-echo ultrasound and inverse impedance spectroscopy. Compared to traditional direct current poling (DCP), the beam mode electromechanical coupling coefficient (k33′) of PMN-0.25PT for ACP reaches up to 89.1% from 84.5% of DCP. As the attribution of the special periodic stripe domain structure (109° domain), the lateral vibration will be suppressed effectively in the array transducer. This indicates that AC-poled PMN-0.25PT single crystals can be an efficient strategy to obtain higher sensitivity and a larger bandwidth in ultrasonic transducers.