bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of Al‐N Based Active Lewis Pairs with Ketones and 1,2‐Diketones: Insertion into Al‐N Bonds, C‐C and C‐N Bond Formation and a Tricyclic Saturated Tetraaza Compound
Authors: Horstmann Julia Silissa , Klabunde Sina , Hepp Alexander , Layh Marcus , Hansen Michael Ryan , Eckert Hellmut , Würthwein Ernst‐Ulrich , Uhl Werner
Published: July 2020

The monomeric aluminum hydrazide iBu2Al‐N(C10H15)(NC5H10) (1) features a strained AlN2 ring and is an efficient active Lewis pair. It reacted with 2,3‐diphenyl‐2‐cyclopropen‐1‐one by insertion of the C=O group into an Al‐N bond, cleavage of the C3 ring and formation of an AlOC3 heterocycle (2). Diacetyl, Me(O)C–C(O)Me, and 1 afforded by insertion of keto groups into both Al‐N bonds a heterocyclic α‐keto‐hemihydrazinal coordinated to aluminum (3). 3 contains fused AlO2C2 and C2N2 heterocycles. In an unexpected reaction, benzil, PhC(O)‐C(O)Ph, afforded by C–C and C–N bond formation a unique tricyclic dimer (4) of the hydrazone H10C5N–N=C10H14, which is the starting material for the synthesis of 1. This reaction may involve a radical process, and benzil radical anions coordinated to Al were detected as by‐products. In contrast, 1 reacted with simple ketones to yield alcoholates [iBu2AlOR]2 [R = OC(H)(Ph)‐C≡C‐Ph (5), OCHPh2 (6)] by retrohydroalumination and reaction of resulting iBu2Al‐H with C=O groups.
Preparation of Electrolyte for Vanadium Redox‐Flow Batteries Based on Vanadium Pentoxide
Authors: Martin Jan , Schafner Katharina , Turek Thomas
Published: July 2020

The vanadium redox‐flow battery is a promising technology for stationary energy storage. A reduction in system costs is essential for competitiveness with other chemical energy storage systems. A large share of costs is currently attributed to the electrolyte, which can be significantly reduced by production based on vanadium pentoxide (V2O5). In this study, the dissolution kinetics of V2O5 in diluted sulfuric acid and commercial vanadium electrolyte (VE) is determined. The low solubility of V2O5 in sulfuric acid can be overcome by partially using VE with a state of charge of −50% as solvent. In this way, a complete dissolution of V2O5 is possible within ≈10 min to achieve the desired vanadium concentration of 1.6 mol L−1. Moreover, the electrochemical reduction of an electrolyte containing VO2+ coupled with the oxygen evolution reaction at the anode is investigated. For these consecutive steps, an electrical energy demand of 1.69 kWh kg−1 is required to reach a state of charge of −50%. Finally, both processes are integrated into a plant concept for continuous electrolyte production.
Practical investigation of usage of nano bottom in the production of fresh water from brackish wastewater in a closed shallow solar basin
Authors: Farahbod Farshad
Published: July 2020

Lack of fresh water is a concern for the future of human because commonly used technologies for producing drinking water from saline water, such as reverse osmosis, electrolysis has been expensive to produce and or, like flash techniques and multi‐stage distillation, are dependent on the fossil energies. In this study, the shallow solar basin has been proposed to simply collect and store solar thermal energy to produce drinking water from salt water. Also, the use of nano particles increases the rate of evaporation in the shallow solar basin. In this way, the experiments have been conducted to optimize the efficient factors in the operation of a shallow solar basin equipped with a nano plate at the bottom of the pool. This shallow solar basin is concentrated in saline water and produces distilled water as the main processing stage for distillation of zero discharge. In this way, concentrated saline water prepares the inflow for evaporation units. The main parameters such as insolation rate, values of produced drinkable water and average temperature of shallow solar basin layers are investigated in this study. The comparison between evaporation rate values in a shallow solar basin equipped with nano plates and conventional solar basin shows an increase of 20%. The results show better performance of the proposed shallow solar basin than the simple shallow solar basin. The test results show the maximum and minimum evaporation rates of 5 and 2 L in June and January 2019, respectively.
Mechanisms of lateral and linear extension of gullies (dongas) in a subhumid grassland of South Africa
Authors: Podwojewski Pascal , Janeau Jean Louis , Caquineau Sandrine , Hughes Jeffrey
Published: July 2020

The formation of deep gullies (called ‘dongas’ locally) in rangeland in KwaZulu‐Natal Province in South Africa is a natural phenomenon. These U‐shaped, very wide gullies have considerable lateral expansion due to the episodic collapse of sidewalls.

The dongas have developed in duplex soils such as Luvisols and Lixisols formed on Permian sedimentary rocks or unconsolidated Quaternary colluvium. This study combined morphological, mineralogical and chemical characterization with measurements of grain‐size content, structural stability and the complete shrinkage curve to detect changes in soil properties of the different horizons located in the gully banks.

The different soil horizons present clear and sharp differences in physical and mineralogical properties. The topsoil with complete grass cover is very resistant to soil detachment. However, the leached E horizon and the BC horizon have low structural stability. The soil profile down to and including the Bt horizon contains exclusively illite in the clay fraction, while the BC colluvial layer and the C horizon (mudstone) contain expandable interstratified illite–smectite. The Bt horizon has a high water content at saturation and high shrinkage, while the BC and C horizons have a high residual shrinkage and a very low water content at saturation.

Because this type of gully expansion is not significantly linked to slope value or the stream power index (SPI) at the gully head, to land‐use change, high rainfall intensities or the threshold of concentrated runoff being exceeded at the gully head, other causes were investigated. It was concluded that the heterogeneity between horizons with different mineralogical properties and structural stabilities, soil types and parent material, anisotropic water‐saturation and shrink‐swell properties are of major importance. This heterogeneity between different soil horizon morphologies and their physical properties can explain why the relationship between the critical slope and the drainage area for gully initiation showed a threshold for gullying much lower than that found elsewhere. © 2020 John Wiley & Sons, Ltd.
Migrating Schwann cells direct axon regeneration within the peripheral nerve bridge
Authors: Min Qing , Parkinson David B. , Dun Xin‐Peng
Published: July 2020

Schwann cells within the peripheral nervous system possess a remarkable regenerative potential. Current research shows that peripheral nerve‐associated Schwann cells possess the capacity to promote repair of multiple tissues including peripheral nerve gap bridging, skin wound healing, digit tip repair as well as tooth regeneration. One of the key features of the specialized repair Schwann cells is that they become highly motile. They not only migrate into the area of damaged tissue and become a key component of regenerating tissue but also secrete signaling molecules to attract macrophages, support neuronal survival, promote axonal regrowth, activate local mesenchymal stem cells, and interact with other cell types. Currently, the importance of migratory Schwann cells in tissue regeneration is most evident in the case of a peripheral nerve transection injury. Following nerve transection, Schwann cells from both proximal and distal nerve stumps migrate into the nerve bridge and form Schwann cell cords to guide axon regeneration. The formation of Schwann cell cords in the nerve bridge is key to successful peripheral nerve repair following transection injury. In this review, we first examine nerve bridge formation and the behavior of Schwann cell migration in the nerve bridge, and then discuss how migrating Schwann cells direct regenerating axons into the distal nerve. We also review the current understanding of signals that could activate Schwann cell migration and signals that Schwann cells utilize to direct axon regeneration. Understanding the molecular mechanism of Schwann cell migration could potentially offer new therapeutic strategies for peripheral nerve repair.
Study of turbulent natural convection coupled with thermal radiation in a vertical cavity having a large form factor
Authors: Rahmoune Imène , Bougoul Saadi
Published: July 2020

In this study, a numerical simulation study of turbulent natural convection coupled with thermal radiation in a vertical cavity differentially heated and filled with air assumed as a transparent fluid was carried out. The cavity has a variable form factor which can reach large values. The vertical walls are subjected to constant temperatures (Tc and Tf), whereas the horizontal walls are assumed adiabatic. The flow inside the cavity is turbulent and turbulence was modeled by using the model, and to take into account of the radiative transfer, the discrete ordinate model (DO) was introduced. To solve the different equations, Ansys‐Fluent software based on the finite volume method was used. Some numerical results obtained for the Rayleigh number value of 1011 have been validated by some existing results in the theory. It is found that the thermal radiation has a significant influence on the flow structure and temperature variation where the flow becomes reinforced. It accelerates the airflow inside the cavity and gives the formation of significant velocity and temperature gradients along the walls of the cavity. Taking into account of the surface, thermal radiation is essential in the correct evaluation of temperature in the cavity.
FRET Dyes Significantly Affect SAXS Intensities of Proteins
Authors: Reinartz Ines , Weiel Marie , Schug Alexander
Published: July 2020

Structural analyses in biophysics aim at revealing a relationship between a molecule's dynamic structure and its physiological function. Förster resonance energy transfer (FRET) and small‐angle X‐ray scattering (SAXS) are complementary experimental approaches to this. Their concomitant application in combined studies has recently opened a lively debate on how to interpret FRET measurements in the light of SAXS data with the popular example of the radius of gyration, commonly derived from both FRET and SAXS. There still is a lack of understanding in how to mutually relate and interpret quantities equally obtained from FRET or SAXS, and to what extent FRET dyes affect SAXS intensities in combined applications. In the present work, we examine the interplay of FRET and SAXS from a computational simulation perspective. Molecular simulations are a valuable complement to experimental approaches and supply instructive information on dynamics. As FRET depends not only on the mutual separation but also on the relative orientations, the dynamics, and therefore also the shapes of the dyes, we utilize a novel method for simulating FRET‐dye‐labeled proteins to investigate these aspects in atomic detail. We perform structure‐based simulations of four different proteins with and without dyes in both folded and unfolded conformations. In‐silico derived radii of gyration are different with and without dyes and depend on the chosen dye pair. The dyes apparently influence the dynamics of unfolded systems. We find that FRET dyes attached to a protein have a significant impact on theoretical SAXS intensities calculated from simulated structures, especially for small proteins. Radii of gyration from FRET and SAXS deviate systematically, which points to further underlying mechanisms beyond prevalent explanation approaches.
Market discipline in South Asia: Evidence from commercial banking sector
Authors: Afzal Ayesha , Mirza Nawazish , Arshad Fatima
Published: July 2020

The paper investigates the presence of market discipline in the banking sectors of India and Pakistan, using the CAMEL approach and the stringent calculations of liquidity and capital as per Basel II. It employs a fixed effects model to market discipline as reflected in the capital adequacy, asset quality profitability, management and liquidity of banks, with bank size and changes and GDP as control variables, for the years 2008 to 2017. The results show varying degrees of market discipline in both India and Pakistan, which manifest through different variables.
Relevance of size in predicting bank failures
Authors: Alzugaiby Basim , Gupta Jairaj , Mullineux Andrew , Ahmed Rizwan
Published: July 2020

Employing a statistical model‐building strategy, this study aims to analyse the United States' bank failures across different size categories (small, medium, and large). Our results suggest that factors associated with bank failures vary across respective size categories, and the average marginal effects (AMEs) of mutually significant covariates also exhibit significant variability across different size classes of banks. The results are robust to up‐to 3 years of lagged regression estimates, various control variables, interaction between bank size and bank charter, alternative bank size classifications, and macroeconomic crisis periods.
Is it safe to perform amnioinfusion in the presence of suspected intraamniotic infection?
Authors: Meyer Raanan , Rottenstreich Amihai , Tsur Abraham , Shai Daniel , Yoeli Rakefet , Levin Gabriel
Published: July 2020

Objective

To study the effect of amnioinfusion in the presence of suspected intra‐amniotic infections (SII) on maternal outcomes among women delivering at term.

Methods

A retrospective cohort study was conducted at a tertiary medical center. All consecutive singleton term deliveries with SII during 2011–2019 were included. Cases where amnioinfusion was performed after the diagnosis of SII were compared to cases without amnioinfusion, matched by cervical dilation at diagnosis of SII. Maternal and obstetric adverse outcomes were compared.

Results

After matching for cervical dilation at diagnosis of SII, the study cohort included 786 women: 62 (7.9%) women in the amnioinfusion group and 724 (92.1%) in the control group. A composite of adverse maternal outcomes occurred in 106 (13.5%) deliveries. There were no significant differences in the rates of maternal adverse outcomes between the amnioinfusion and control groups (11.0% vs 13.7%, respectively; P=0.59), including postpartum endometritis (5.0% vs 3.3%, respectively; P=0.46) and febrile morbidity (10.0% vs 6.5%, respectively; P=0.42). Neonatal blood gas outcomes and Apgar scores did not differ between groups.

Conclusion

The use of amnioinfusion for alleviating non‐reassuring fetal heart rate in the presence of SII is safe and does not increase the rate of maternal adverse outcome.
Role of PIWI‐interacting RNAs on cell survival: Proliferation, apoptosis, and cycle
Authors: Zeng Qian , Wan Hengquan , Zhao Simin , Xu Haiqiang , Tang Tingting , Oware Kwabena Agyare , Qu Shunlin
Published: July 2020

PIWI‐interacting RNAs (piRNAs) are a kind of non‐coding small RNAs, which play a biological role by specifically binding to PIWI proteins. Studies have demonstrated that piRNAs play a significant role in germline cell growth by repressing transposable elements, especially in the regulation of DNA methylation. Recently increasing evidence revealed that piRNAs involved in the regulation of cell proliferation, apoptosis, and cycle; however, the mechanism of piRNAs is unclear. This review summarizes the research progress regarding the roles of piRNAs in the cell proliferation, apoptosis, and cycle.
Prevalence of dengue virus serotypes in the 2017 outbreak in Peshawar, KP, Pakistan
Authors: Khan Najeeb Ullah , Danish Lubna , Khan Hydayat Ullah , Shah Maryam , Ismail Muhammad , Ali Ijaz , Petruzziello Arnolfo , Sabatino Rocco , Guzzo Annunziata , Botti Gerardo , Iqbal Aqib
Published: July 2020

Background

Dengue is a viral disease, transmitted by infected Aedes aegypti and Aedes albopictus female mosquitoes. Worldwide, 96 million infections were estimated in 2010. The dengue virus comprises four distinct serotypes (DENV‐1, DENV‐2, DENV‐3, and DENV‐4) which belong to the genus Flavivirus. Determining the serotypes during dengue outbreaks is crucial for its effective management in terms of diagnostics improvement and polyvalent vaccine development. The aim of the present study is to determine the prevalence rate of dengue virus serotypes in the samples collected from patients during the 2017 outbreak in Khyber Pakhtunkhwa, Pakistan.

Methods

A total of 800 ELISA‐positive samples were collected, of which 513 (290 males, 223 females) samples were confirmed positive by PCR.

Results

Out of 513, 25 were found serotype 1 (5%), 196 were serotype 2 (38%), 192 were serotype 3 (37%), 56 were serotype 4 (11%), and 44 (8%) were found to have mix serotypes.

Conclusion

We can conclude that serotypes 2 and 3 of dengue virus were the predominated serotypes of dengue virus in the 2017 outbreak in Peshawar, capital city of Khyber Pakhtunkhwa, Pakistan.
Relationship of vitamin D receptor gene polymorphism with sarcopenia and muscle traits based on propensity score matching
Authors: Yao Xuemei , Yang Lei , Li Meiyan , Xiao Hui
Published: July 2020

Background

Vitamin D receptor (VDR) gene polymorphism is reported to be associated with muscle mass and muscle strength. Loss of skeletal muscle mass and decreased muscle strength are the main characteristics of sarcopenia. In this study, the relationship of VDR gene polymorphism with muscle traits (muscle mass, muscle strength, and physical performance) and sarcopenia were studied in Xinjiang, China.

Methods

Totally, 205 sarcopenia patients were enrolled. Propensity score method was used to match control group. FokI and BsmI polymorphisms were genotyped using improved multiplex ligation detection reaction (iMLDR).

Results

Fok1, but not Bsm1, polymorphism was significantly associated with sarcopenia. Patients with Fok1 GG genotype were more likely to have sarcopenia. Both Bsm1 and Fok1 polymorphism were related to muscle traits. Patients with Bsm1 CT genotype had lower gait speed (GS) but higher skeletal mass index. Patients with Fok1 GG genotype had lower GS, and female subjects with the Fok1 GG genotype had lower handgrip strength (HS). GS was decreased in Bsm1 CT genotype than CC carriers. HS and GS were decreased in Fok1 GG genotype than AA carriers.

Conclusion

Fok1, but not Bsm1, polymorphism is associated with sarcopenia. Both Bsm1 and Fok1 polymorphism affect both HS and GS.
Determinants of depression in women with chronic disease: Evidence from a sample of poor loan takers from Pakistan
Authors: Jafree Sara Rizvi
Published: July 2020

Depression is one of the most common mental health problems in Pakistani women, with prevalence rates estimated to be above 30%. Identification of the determinants of depression in chronically ill, poor, and debt‐ridden women of the country is a neglected area. A quantitative survey using standardized tools was used to sample women from across Pakistan. It was found that women had higher odds of depression when they (a) perceived unfavorable self‐health, (b) had less health decision‐making power, (c) encountered difficulties in healthcare services, and (d) faced food insecurity. Key reforms are recommended to improve state protection policies, mental healthcare services, and cultural support for disadvantaged women in the country.
Osthole interacts with an ER‐mitochondria axis and facilitates tumor suppression in ovarian cancer
Authors: Bae Hyocheol , Lee Jin‐Young , Song Jisoo , Song Gwonhwa , Lim Whasun
Published: July 2020

Osthole is a natural coumarin found in a variety of plants and has been reported to have diverse biological functions, including antimicrobial, antiviral, immunomodulatory, and anticancer effects. Here, we investigated the natural derivative osthole as a promising anticancer compound against ovarian cancer and evaluated its ability to suppress and abrogate tumor progression. In addition, we found the endoplasmic reticulum‐mitochondrial axis‐mediated anticancer mechanisms of osthole against ES2 and OV90 ovarian cancer cells and demonstrated its calcium‐dependent pharmacological potential. Mechanistically, osthole was found to target the phosphatidylinositol 3‐kinase/mitogen‐activated protein kinase signaling pathway to facilitate tumor suppression in ovarian cancer. Furthermore, we identified the effects of osthole in a three‐dimensional tumor‐formation model using the zebrafish xenograft assay, providing convincing evidence of the pharmacological effects of osthole within the anchorage‐independent tumor microenvironment. These findings suggest that osthole has strong potential as a pharmacological agent for targeting ovarian cancer.
COVID‐19 and olfactory dysfunction: A possible associative approach towards neurodegenerative diseases
Authors: Mahalaxmi Iyer , Kaavya Jayaramayya , Mohana Devi Subramaniam , Balachandar Vellingiri
Published: July 2020

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the agent of novel coronavirus 2019 (COVID‐19), has kept the globe in disquiets due to its severe life‐threatening conditions. The most common symptoms of COVID‐19 are fever, sore throat, and shortness of breath. According to the anecdotal reports from the health care workers, it has been suggested that the virus could reach the brain and can cause anosmia, hyposmia, hypogeusia, and hypopsia. Once the SARS‐CoV‐2 has entered the central nervous system (CNS), it can either exit in an inactive form in the tissues or may lead to neuroinflammation. Here, we aim to discuss the chronic infection of the olfactory bulb region of the brain by SARS‐CoV‐2 and how this could affect the nearby residing neurons in the host. We further review the probable cellular mechanism and activation of the microglia 1 phenotype possibly leading to various neurodegenerative disorders. In conclusion, SARS‐CoV‐2 might probably infect the olfactory bulb neuron enervating the nasal epithelium accessing the CNS and might cause neurodegenerative diseases in the future.
Predicting soil pH changes in response to application of urea and sheep urine
Authors: Curtin D. , Peterson M. E. , Qiu W. , Fraser P. M.
Published: July 2020

Volatilization of NH3 following urea application or livestock urine deposition can result in significant loss of N to the environment. Urea hydrolysis to NH4+ results in an increase in pH, which in turn promotes transformation of NH4+ to NH3. Accurately predicting changes in soil pH following urea (or urine) application will allow successful simulation of NH3 volatilization. The magnitude of the pH change depends on the soil's pH buffering capacity (pHBC). However, as actual pHBC values are not generally available, pHBC proxies (e.g., cation exchange capacity) have been used in modeling studies. In a 34‐d laboratory incubation study, we measured soil pH and mineral N (NH4+ and NO3−) following a large application of urea (800 mg N kg−1 soil) to four soils with a range of pHBC values. In a second incubation, pH changes and mineral N dynamics were monitored in soil treated with sheep urine (773 mg N kg−1 soil) in the absence and presence of the nitrification inhibitor dicyandiamide. In both incubations, pH changes associated with urea hydrolysis and subsequent nitrification of NH4+ were predicted well using measured pHBC data. Our results confirmed that pHBC is base‐type dependent (values greater when measured using KOH than NH4OH). Soil pHBC is easily measured, and the use of a measured value (determined using NH4OH) can improve model simulations of pH in the field and, potentially, lead to improved estimates of NH3 loss from animal‐deposited urine patches and urea‐treated soil.
The mechanism of Chinese herbal formula HQT in the treatment of rheumatoid arthritis is related to its regulation of lncRNA uc.477 and miR-19b
Authors: Wang Maojie , Mei Liyan , Liu Zehao , Tang Xuan , Wu Xiaodong , Chen Xiumin , Zhao Yue , Huang Qingchun , Huang Runyue
Published: July 2020

Rheumatoid arthritis (RA) pathogenesis has been associated with dysregulation of long noncoding RNA (lncRNA) and microRNA (miRNA) expression in serum and in lesioned tissue. In this study, a microarray assay was performed to study the profile of lncRNAs in the serum of RA patients and healthy donors, and a set of novel lncRNAs associated with RA was identified. For the remainder of the study, focus is on the top hit, lncRNA uc.477. The upregulation of lncRNA uc.477 and downregulation of miR-19b were validated in the serum of RA patients compared to that of healthy donors, and similar results were further confirmed by quantitative real-time PCR analysis of a cell line: RA-derived human fibroblast-like synoviocytes (HFLS-RA). LncRNA uc.477 could interfere with the processing of pri-miR-19b to produce its mature form and thereby played a pro-inflammatory role. In addition, Huayu Qiangshen Tongbi formula (HQT), a traditional Chinese medicine (TCM), has been shown to exert a promising therapeutic effect on RA and to exhibit long-term safety in our previous clinical retrospective study. Importantly, HQT treatment normalized the levels of lncRNA uc.477 and miR-19b in HFLS-RA in vitro and in mouse models of collagen-induced arthritis. HQT treatment, knockdown of lncRNA uc.477, and overexpression of miR-19b resulted in a comparable inhibition of pro-inflammatory cytokine gene expression in HFLS-RA cells. Together, these data suggest that the therapeutic effects of HQT on RA are closely related to its modulation of lncRNA uc.477 and miR-19b.
Analysis of textbook outcomes among patients undergoing resection of retroperitoneal sarcoma: A multi‐institutional analysis of the US Sarcoma Collaborative
Authors: Wiseman Jason T. , Ethun Cecilia G. , Cloyd Jordan M. , Shelby Rita , Suarez‐Kelly Lorena , Tran Thuy , Poultsides George , Mogal Harveshp , Clarke Callisia , Tseng Jennifer , Roggin Kevin K. , Chouliaras Konstantinos , Votanopoulos Konstantinos , Krasnick Bradley , Fields Ryan , Walle Kara Vande , Ronnekleiv‐Kelly Sean , Howard John Harrison , Cardona Kenneth , Grignol Valerie
Published: July 2020

Background

The novel composite metric textbook outcome (TO) has increasingly been used as a quality indicator but has not been reported among patients undergoing surgical resection for retroperitoneal sarcoma (RPS) using multi‐institutional collaborative data.

Methods

All patients who underwent resection for RPS between 2000 to 2016 from eight academic institutions were included. TO was defined as a patient with R0/R1 resection that discharged to home and was without transfusion, reoperation, grade ≥2 complications, hospital‐stay >50th percentile, or 90‐day readmission or mortality. Univariate and multivariable analyses were performed.

Results

Among 627 patients, 56.1% were female and the median age was 59 years. A minority of patients achieved a TO (34.9%). Factors associated with achieving a TO were tumor size <20 cm and low tumor grade, while ASA class ≥3, history of a prior cardiac event, resection of left colon/rectum, distal pancreatic resection, major venous resection and drain placement were associated with not achieving a TO (all P < .05). Achievement of a TO was associated with improved survival (median:12.7 vs 5.9 years, P < .01).

Conclusions

Among patients undergoing resection for RPS, failure to achieve TO is common and associated with significantly worse survival. The use of TO may inform patient expectations and serve as a measure for patient‐level hospital performance.
Comprehensive evaluation of the antioxidant capacity of Sceptridium ternatum using multiple colorimetric methods and 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography analysis
Authors: Zhu Junfeng , Zhong Like , Kong Sisi , Zhang Yuting , Huang Ping
Published: July 2020

Sceptridium ternatum is a medicinal herb with multiple health benefits. However, its antioxidant activity and active components have not been clarified. In this study, the antioxidant capacity of S. ternatum was comprehensively investigated using multiple colorimetric methods and 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography analysis. First, the phenolic content, flavonoid content, and radical scavenging ability of S. ternatum were parallelly determined using colorimetric methods performed in 96‐well microplates. The flavonoid content, rather than the phenolic content, was highly correlated with its antioxidant activity. Sceptridium ternatum was shown to be a rich source of flavonoids, with a highest flavonoid yield of 3.44 ± 0.11 mg/g. Subsequently, 1,1‐diphenyl‐2‐picrylhydrazyl–high‐performance liquid chromatography experiment and quadrupole time‐of‐flight mass spectrometry analyses were carried out for rapid screening of the individual antioxidants. A total of 14 O‐glycosyl flavonoids with quercetin or kaempferol aglycone have been characterized. Particularly, quercetin 3‐O‐rhamnoside‐7‐O‐glucoside exhibited the most potent antioxidant ability. Its half‐maximal effective concentrations for scavenging 1,1‐diphenyl‐2‐picrylhydrazyl and 2,2ʹ‐azino‐bis (3‐ethylbenzthiazoline‐6‐sulfonic acid) radicals were 70.55 ± 2.69 and 106.90 ± 1.76 µg/mL, respectively, which were comparable with those of l‐ascorbic acid. Our results indicated that the combined colorimetric and chromatographic methods provided a practical strategy for the discovery of bioactive compounds from natural products.
A new method to quantify air–water gas exchanges in streams based on slug injection and semicontinuous measurement
Authors: Vautier Camille , Abhervé Ronan , Chatton Eliot , Labasque Thierry , de Dreuzy Jean‐Raynald
Published: July 2020

Gas exchanges between streams and atmosphere strongly impact biogeochemical cycles, yet their quantification in space and time remains challenging. We propose a new method to measure gas exchange rate coefficients in headwater streams. The method is based on simultaneous slug injections of a conservative tracer and a volatile tracer, coupled to in situ semicontinuous measurements. Its originality lies in the mathematical exploitation of the tracers' breakthrough curves. Taking advantage of the entire breakthrough curves, we infer the gas exchange rate coefficient from a comparative analysis of the shape of the volatile and the conservative breakthrough curves. Tests on synthetic datasets confirmed the validity of the mathematical framework for the whole range of gas exchange rate coefficients found in headwater streams. Field experiments further attested to the real‐world applicability of the method. Salt and helium injections were performed in a first‐order stream and the helium breakthrough curves were obtained using in situ membrane inlet mass spectrometry. This new method allows to determine the gas exchange rates directly in the field, without any external calibration of the data. Its fast implementation enables a wider spatial coverage of the measurements of gas exchange rates, and thus offers an opportunity to improve the large‐scale estimates of CO2 emissions from headwater streams. More generally, our study highlights the informative potential of semicontinuous datasets and encourages further investigation of possible use of temporal signals.
Physicochemical studies of galvanized steel corrosion in urban, industrial, and marine environments, and corrosion mapping of Karachi city: An important coastal city of the 21st‐century modern maritime silk route
Authors: Zafar Faiza , Bano Humaira , Mahmood Azhar , Corvo Francisco , Rodriguez Joelis
Published: July 2020

The coastal city of Karachi is an imperative part of China–Pakistan Economic Corridor, which is integrated with the modern maritime silk route of the 21st century. This paper presents the corrosion mapping and physicochemical studies of galvanized steel corrosion exposed at the urban, industrial, and marine test sites located in the Karachi coastal city from July 2018 to June 2019. Tests have been performed to determine chloride, sulfur dioxide, time of wetness (TOW), and corrosion rates as per ISO protocols 9223 and 9225, and ASTM standards G1, G50, G140‐02, D4458‐94, and D2010. All test sites have been assigned the C5+ corrosivity category, based on corrosion rates of the galvanized steel, which is not completely in line with the corrosivity category derived from atmospheric pollutants and TOW values for these test sites. SEM/EDS, XRD, and FTIR have characterized the presence of simonkolleite, hydrozincite, and zincite at nearly all the test sites, whereas gordaite is only detected at the marine test sites. Zinc(I) chlorohydroxysulfate is also observed at an urban test site. This study has furnished a novel product of a galvanized steel corrosion map for Karachi, Pakistan.
Do analysts follow firms with able managers?
Authors: Gao Kaijuan , Wang Chenglong , Su Qi , Shen Hanxiao
Published: July 2020

Although previous studies suggest that management quality impacts analyst behavior, there is a dearth in direct empirical evidence that proves this. A sample of listed Chinese firms over the period 2008–2016 proves that a firm with highly skilled managers draws more analysts. We use an instrumental variable approach to mitigate endogeneity issues. Tests show that the positive impact of managerial ability on analyst following is more salient in firms with no political connections and firms located in regions with developed formal institutions. Firms with high‐capability managers help analysts improve their forecast accuracy and lower the dispersion of their opinions.
Analysis of the water vapour transport and accumulation mechanism during the “7.31” extreme rainstorm event in the southeastern Hami area, China
Authors: Liu Jing , Liu Fan , Tuoliewubieke Dilinuer , Yang Lianmei
Published: July 2020

A combination of reanalysis, merged‐product, satellite, observation station and Global Positioning System (GPS)‐based precipitable water vapour data is used to analyse the characteristics of water vapour transmission and aggregation during an extreme rainstorm event that occurred in the southeastern Hami area of Xinjiang, China, in July 2018. The strengthening of the low‐level easterly jet stream in the Hexi Corridor and terrain convergence were the main drivers for the rapid accumulation of water vapour. Results suggest there was continuous water vapour transport toward the rainstorm area which occurred in three different stages. During the first stage, the rainstorm area humidified slowly under the influence of the mid‐latitude trough. In the second stage, the location of the western Pacific subtropical high (WPSH) was anomalously shifted to the north, and a southerly air flow carrying water vapour from the South China Sea merged with the easterly jet stream south of the WPSH, near the Hexi Corridor. The wet water vapour from the ocean was transported to the southeastern Hami area by an easterly water vapour relay transmission. In the last stage, as the low‐level jet stream in the Hexi Corridor strengthened, the abundant water vapour was accumulated and gathered in the heavy rainstorm area. The extreme precipitation was caused by the transport of water vapour from the lower to the upper level, which made it rapidly converge, rise and condense.
Novel Fully Transparent Emissive Displays on Vehicle Glass
Authors: Sun Ted X.
Published: July 2020

Sun Innovations’ founder describes how his company developed a fully transparent projection display on a novel RGB emissive screen that is applied onto vehicle glazing and presents high‐quality emissive images both inside and outside the vehicle.
Identifying putative cerebrospinal fluid biomarkers of amyotrophic lateral sclerosis in a north Indian population
Authors: Khosla Radhika , Rain Manjari , Chawathey Shreyas , Modgil Shweta , Tyagi Rahul , Thakur Keshav , Pannu Viraaj , Sharma Suresh Kumar , Anand Akshay
Published: July 2020

Introduction

Evidence‐based information about cerebrospinal fluid (CSF) levels of biomarkers in patients with amyotrophic lateral sclerosis (ALS) is limited.

Methods

Vascular endothelial growth factor (VEGF) and its receptor vascular endothelial growth factor receptor 2 (VEGFR2), optineurin (OPTN), monocyte chemoattractant protein‐1 (MCP‐1), angiogenin (ANG), and TAR DNA‐binding protein (TDP‐43) were quantified by enzyme‐linked immunoassay in the CSF of 54 patients with sporadic ALS and 32 controls in a case‐control study design.

Results

CSF levels of VEGF (P = .014) and ANG (P = .009) were decreased, whereas VEGFR2 was higher (P = .002) in patients with ALS than in controls. TDP‐43 positively correlated with MCP‐1 (P = .003), VEGF (P < .001), and VEGFR2 (P < .001) in patients with ALS.

Discussion

Our findings suggest possible utility of VEGF, VEGFR2, and ANG as biomarkers for use in ALS treatment trials.
Flood resilience loci SUBMERGENCE 1 and ANAEROBIC GERMINATION 1 interact in seedlings established underwater
Authors: Alam Rejbana , Hummel Maureen , Yeung Elaine , Locke Anna M. , Ignacio John Carlos I. , Baltazar Miriam D. , Jia Zhenyu , Ismail Abdelbagi M. , Septiningsih Endang M. , Bailey‐Serres Julia
Published: July 2020

Crops with resilience to multiple climatic stresses are essential for increased yield stability. Here, we evaluate the interaction between two loci associated with flooding survival in rice (Oryza sativa L.). ANAEROBIC GERMINATION 1 (AG1), encoding TREHALOSE 6‐PHOSPHATE PHOSPHATASE 7 (TPP7), promotes mobilization of endosperm reserves to enhance the elongation of a hollow coleoptile in seeds that are seeded directly into shallow paddies. SUBMERGENCE 1 (SUB1), encoding the ethylene‐responsive transcription factor SUB1A‐1, confers tolerance to complete submergence by dampening carbohydrate catabolism, to enhance recovery upon desubmergence. Interactions between AG1/TPP7 and SUB1/SUB1A‐1 were investigated under three flooding scenarios using four near‐isogenic lines by surveying growth and survival. Pyramiding of the two loci does not negatively affect anaerobic germination or vegetative‐stage submergence tolerance. However, the pyramided AG1 SUB1 genotype displays reduced survival when seeds are planted underwater and maintained under submergence for 16 d. To better understand the roles of TPP7 and SUB1A‐1 and their interaction, temporal changes in carbohydrates and shoot transcriptomes were monitored in the four genotypes varying at the two loci at four developmental timeponts, from day 2 after seeding through day 14 of complete submergence. TPP7 enhances early coleoptile elongation, whereas SUB1A‐1 promotes precocious photoautotrophy and then restricts underwater elongation. By contrast, pyramiding of the AG1 and SUB1 slows elongation growth, the transition to photoautotrophy, and survival. mRNA‐sequencing highlights time‐dependent and genotype‐specific regulation of mRNAs associated with DNA repair, cell cycle, chromatin modification, plastid biogenesis, carbohydrate catabolism and transport, elongation growth, and other processes. These results suggest that interactions between AG1/TPP7 and SUB1/SUB1A‐1 could impact seedling establishment if paddy depth is not effectively managed after direct seeding.
High‐flow nasal cannula vs standard respiratory care in pediatric procedural sedation: A randomized controlled pilot trial
Authors: Klotz Daniel , Seifert Viktor , Baumgartner Jana , Teufel Ulrike , Fuchs Hans
Published: July 2020

Introduction

Respiratory instability is frequently observed during pediatric procedural sedation. The aim of this trial was to estimate the impact of high‐flow nasal cannula (HFNC) therapy on respiratory stability during sedation for upper gastrointestinal tract endoscopy in children.

Methods

Prospective randomized controlled non‐blinded single‐center pilot trial. Children were randomly allocated to receive either HFNC (2 L/kg/min) or low‐flow nasal oxygen cannula (LFNC, standard care). FiO2 was titrated to maintain SpO2 94% to 98% in both groups. Primary outcome was the number of events of respiratory instability defined by prespecified criteria (hypoxia, hypercapnia, apnea). Secondary outcomes included type and duration of events, number of interventions to regain respiratory stability and cumulative doses of medication.

Results

Fifty children (mean age, 12.3 ± 3.1 years) were enrolled and treated with HFNC (n = 25) or LFNC (n = 25). Patient and intervention characteristics were not different in the two study groups, including total oxygen flow rate. Mean (SD) number of respiratory events in the HFNC group was 2.0 ± 1.9 events compared to 2.0 ± 1.4 events in the LFNC group (P = .65; 95% CI of difference, −1.0 to 1.0). There was no difference for any secondary outcome criteria, percentage of patients for any outcome criteria and no difference in the number of respiratory events or airway management maneuvers per patient between treatment groups.

Conclusions

HFNC did not increase respiratory stability in sedated children undergoing upper gastrointestinal tract endoscopy compared to LFNC.
Cumulative deamidations of the major lens protein γS‐crystallin increase its aggregation during unfolding and oxidation
Authors: Vetter Calvin J. , Thorn David C. , Wheeler Samuel G. , Mundorff Charlie C. , Halverson Kate A. , Wales Thomas E. , Shinde Ujwal P. , Engen John R. , David Larry L. , Carver John A. , Lampi Kirsten J.
Published: July 2020

Age‐related lens cataract is the major cause of blindness worldwide. The mechanisms whereby crystallins, the predominant lens proteins, assemble into large aggregates that scatter light within the lens, and cause cataract, are poorly understood. Due to the lack of protein turnover in the lens, crystallins are long‐lived. A major crystallin, γS, is heavily modified by deamidation, in particular at surface‐exposed N14, N76, and N143 to introduce negative charges. In this present study, deamidated γS was mimicked by mutation with aspartate at these sites and the effect on biophysical properties of γS was assessed via dynamic light scattering, chemical and thermal denaturation, hydrogen‐deuterium exchange, and susceptibility to disulfide cross‐linking. Compared with wild type γS, a small population of each deamidated mutant aggregated rapidly into large, light‐scattering species that contributed significantly to the total scattering. Under partially denaturing conditions in guanidine hydrochloride or elevated temperature, deamidation led to more rapid unfolding and aggregation and increased susceptibility to oxidation. The triple mutant was further destabilized, suggesting that the effects of deamidation were cumulative. Molecular dynamics simulations predicted that deamidation augments the conformational dynamics of γS. We suggest that these perturbations disrupt the native disulfide arrangement of γS and promote the formation of disulfide‐linked aggregates. The lens‐specific chaperone αA‐crystallin was poor at preventing the aggregation of the triple mutant. It is concluded that surface deamidations cause minimal structural disruption individually, but cumulatively they progressively destabilize γS‐crystallin leading to unfolding and aggregation, as occurs in aged and cataractous lenses.
Carrier Dynamics in Al‐Rich AlGaN/AlN Quantum Well Structures Governed by Carrier Localization
Authors: Frankerl Christian , Nippert Felix , Hoffmann Marc Patrick , Brandl Christian , Lugauer Hans-Jürgen , Zeisel Roland , Hoffmann Axel , Davies Matthew John
Published: July 2020

The carrier dynamics of Al‐rich AlGaN/AlN quantum well (QW) structures in the presence of strong carrier localization is reported. Excitation density‐dependent photoluminescence (PL) measurements at low temperatures reveal a clear correlation between the onset of efficiency droop and the broadening of the time‐integrated PL spectra. While the droop onset is heavily impacted by the localization strength, the PL emission broadening is observed almost exclusively on the high energy side of the emission spectrum. Spectrally resolved PL decay transient measurements reveal a strong dependency of the carrier lifetimes on the emission photon energy across the spectrum, consistent with a distribution of localized states, as well as on the temperature, depending on the localization strength of the investigated structure. The characteristic “S”‐shaped temperature dependence of the PL emission energy is shown to be directly correlated to the thermal redistribution of carriers between localized states. Based on these findings, the role of carrier localization in the recombination processes in AlGaN QW structures is underlined and its implications for efficiency droop are discussed.
Structure and Magnetism of EuS on Bi2Se3(0001)
Authors: Meyerheim Holger L. , Ernst Arthur , Mohseni Katayoon , Polyakov Andrey , Maznichenko Igor V. , Buczek Pawel A. , Coati Alessandro , Parkin Stuart S. P.
Published: July 2020

The rocksalt‐type ferromagnetic (FM) insulator EuS (bulk TC = 17 K) grown on Bi2Se3 with well‐matched (111) plane of the film and (0001) plane of the substrate is studied. The system may feature magnetic proximity effect breaking the time‐reversal symmetry and opening a bandgap in the metallic topologically protected surface state of Bi2Se3. The experimental X‐ray diffraction studies are combined with ab initio calculations to resolve contradictory results concerning the enhancement of the TC up to 300 K and the degree of induced magnetization in the system. It is concluded that previous studies relied on idealized and unconfirmed structure models. Herein, it is shown by surface X‐ray diffraction (SXRD) with ab initio calculations that a two double layer‐thick EuS film grows with a sharp interface and without chemical intermixing in a single domain state in an FCC‐type stacking on the Bi2Se3(0001) surface in which the topmost layer is metallic, thereby lifting polarity. A large pz‐orbital‐derived top‐layer sulfur magnetic moment of 0.6 μB is found, whereas for europium, μEu = 6.9 μB throughout the film is found. No magnetization within the first Bi2Se3 quintuple layer is found. The calculation of the exchange parameters Jij indicates a complex FM and antiferromagnetic ordering between europium and sulfur with a maximum Néel temperature of 226 K.
A Most General and Facile Recipe for the Calculation of Heteroepitaxial Strain
Authors: Grundmann Marius
Published: July 2020

A general approach to the calculation of heteroepitaxial strain for arbitrary crystal symmetry (including triclinic) and arbitrary interface plane is presented. The formulas are easily implemented into an algebraic math program. Particular results are derived for rhombohedral heterostructures.
Statistical Analysis and Molecular Dynamics Simulations of the Thermal Conductivity of Lennard–Jones Solids Including Their Pressure and Temperature Dependencies
Authors: Heyes David M. , Dini Daniele , Smith Edward R.
Published: July 2020

Aspects of the thermal conductivity, λ, of a Lennard–Jones (LJ) solid along an isotherm and the sublimation line are studied using equilibrium molecular dynamics (MD) simulations. A reformulation of the Green–Kubo time correlation function expression for λ in the form of a probability distribution function (PDF) of single trajectory contributions (STC) exhibits the same characteristic statistical trends as found previously for liquids, even at high pressures and low temperatures. The analysis reveals that for short periods of time the thermal conductivity can be negative. This feature is evident along the sublimation line isobar and a low‐temperature isotherm going to high densities. Along the isobar and isotherm lines, λ is to a good approximation a power law in temperature and density, respectively. This behavior is used in a more general thermodynamics‐based analysis description of the state point dependence of the thermal conductivity. The heat flux autocorrelation function increasingly develops a damped oscillatory appearance as pressure increases or temperature decreases, consistent with the phonon formulation of thermal conductivity.