bluuebunny/crossref_metadata_2025 huggingface dataset:
In vivo and In vitro Antioxidant Activities of Aqueous and Ethanol Stem Bark Extracts of Vitex doniana on Doxorubicin-induced Oxidative Stress in Rats
Authors: Sulaiman Mohammed Aliyu , Dahiru Daniel , Ibrahim Mohammed Auwal , Hayatu Ahmed Ibrahim
Published: March 2021

Background: Oxidative stress is involved in the pathogenesis of hypertension, myocardial ischemia-reperfusion injury, atherosclerosis, muscular dystrophy, aging and other associated diseases. Vitex doniana is used in Adamawa, northern Nigeria to treat oxidative stress associated diseases. However, the antioxidative effects of the plant have not been scientifically examined in oxidative stress experimental animal models. The aim of this study is to investigate the in vitro and in vivo antioxidant activities of aqueous and ethanol stem bark extracts of Vitex doniana in oxidative stress model of rats.

Methods: The study used 35 adult albino rats weighing 175 ± 25 g, of which 30 were induced with oxidative stress by intraperitoneal injection of doxorubicin (10 mg/kg) for three consecutive days. Animals were treated by oral administration of silymarin (100 mg/kg) and Vitex doniana aqueous or ethanol extract (100 mg/kg and 200 mg/kg) for 14 consecutive days before they were sacrificed on the 15th day and blood was analyzed for biochemical indices of oxidative stress.

Results: The results of the phytochemistry showed the presence of alkaloids, tannins, flavonoids, steroids, phenols, saponins, terpenoids, glycosides: and total flavonoids (52.70 ± 1.60 mg/ml and 75.40 ± 0.80 mg/ml), total phenols (21.45 ± 1.54 mg/ml and 26.50 ± 1.22 mg/ml) for aqueous and ethanol stem bark extracts respectively. The extracts scavenged DPPH radical, reduced Fe3+ and inhibited lipid peroxidation. Doxorubicin significantly (p<0.05) lowered the levels of SOD, CAT, GR and TAS and significantly (p<0.05) but, increased the level of LPO. Oral treatment with Vitex doniana extracts significantly (p<0.05) increased the activities of CAT, GR, SOD and TAS while LPO was significantly (p<0.05) lowered. Vitex doniana stem bark extracts significantly (p<0.05) improved the biochemical derangements observed in the induced untreated animals in comparable manner to that of Silymarin.

Conclusion: The present study provides the scientific rationale for the use of Vitex doniana stem bark in traditional medicine and has a viable antioxidative capacity both in vitro and in vivo.
Activation of Sirtuin 1 by Ellagic Acid Ameliorates Cisplatin-Induced Apoptosis, Oxidative Stress and Nephrotoxicity
Authors: Neamatallah Thikryat , Eid Basma G. , Bagher Amina M. , Nasrullah Mohammed Z. , Ali Soad S. , Mohammedsaleh Zuhair M. , El-Shitany Nagla A.
Published: March 2021

Background: Cisplatin (Cis) is a chemotherapeutic agent commonly applied in treating different cancers. However, acute renal injury remains a major side effect of Cis that limits its clinical use. Oxidative stress in renal tissues play a key role in Cis-induced toxicity. This research aimed to investigate the impact of ellagic acid (Ella) on Cis-induced apoptotic renal injury and the possible involvement of sirtuin 1 (SIRT1) and oxidative stress as a possible protective mechanism.

Methods: Twenty-four Sprague Dawley rats were divided into four groups (n=6) and treated as follows. The control (Cont) group (0.9% saline), Ella group (10 mg/kg), Cis group (7.5 mg/kg), Ella + Cis group (10 mg/kg + 7.5 mg/kg). Ella was administered 7 days prior to Cis injection. Seventy-two hours later, the rats were sacrificed, and blood and kidney samples were collected.  Biochemical analyses were performed on serum and kidney homogenate. The histopathological and immunohistochemical analyses were performed on the formalin preserved kidneys.

Results: Ella significantly decreased serum creatinine and urea levels compared to the Cis group. Furthermore, Ella protects the kidney cortex and medulla against most Cis-induced histopathological changes. Ella significantly decreased kidney contents of malondialdehyde (MDA). Moreover, Ella reversed the Cis-induced reduction of kidney antioxidants, including glutathione peroxidase, superoxide dismutase, and catalase. Ella decreased kidney protein expression of both cyclooxygenase-2 (COX-2) and Bax proteins while increased SIRT1 and Bcl2 expression.

Conclusion: The results revealed a reduction in SIRT1 protein expression in rat renal medullary and cortical tissues following Cis treatment. However, Ella significantly enhanced SIRT1 expression, antioxidants levels, and reduced Cis-induced apoptosis, inflammation, and oxidative stress by increasing the ratio of Bax/Bcl-2 and reducing the expression of COX-2 and MDA, respectively. These findings provide additional evidence of the antioxidant and antiapoptotic effect of Ella in Cis-induced renal toxicity.
Alterations in Serum Myostatin Levels via Swimming Exercise in High Fructose Mediated Metabolic Syndrome Model
Authors: Karaman Muhammed Emre , Arslan Cengiz , Gürsu Mehmet Ferit , Arat Zelal , Türkoğlu Furkan
Published: March 2021

Aims: Metabolic syndrome is a table of abdominal diseases characterized by insulin resistance, obesity, dyslipidemia, and hypertension, and it is a serious risk factor for the development of cardiovascular diseases. The purpose of this study was to understand how metabolic syndrome causes a change in myostatin levels, and to understand if swimming exercise have protective and therapeutic effects in fructose mediated metabolic syndrome model by regulating serum myostatin level.

Methodology: A total of 21 Sprague Dawley male rats were used in the study. Metabolic syndrome was induced by adding 30% fructose into drinking water for 5 weeks The rats (6-8 weeks old, weighing 200-250 g) were randomly divided into 3 groups as 7 rats in each cage. Swimming exercises were applied three days a week for six weeks. On exercise days, rats were exercised for 20 minutes in a day. Blood was collected from all animals in aprotinin tubes to be used in the necessary analysis with decapitation. Serum samples obtained after centrifugation were kept at -80 ℃ until the assay were performed. In serum samples, myostatin was measured by ELISA method.

Results: There was a statistically significant difference resulting from G2, which had the highest value in glucose and triglyceride levels between groups. G2 had the lowest HDL levels. Myostatin levels were significantly higher in G2 compared to other groups.

Conclusion: Moderate swimming exercises are protective and therapeutic in preventing chronic diseases such as diabetes, obesity and metabolic syndrome. In line with these results, it can be said that swimming exercise is a therapeutic practice that regulates impaired fasting serum glucose, increased TG levels and decreased HDL levels and downregulates serum myostatin levels.
Impact of COVID-Pandemic on the Mental Health of Medical Students of Sindh Province, Pakistan
Authors: Dur-re-Shahwar . , Metlo Marvi , Ahmed Zuheeb , Mughal Zaheer , Shaikh Bilawal , Ahmer Arslan , Sultana Razia , Ain Noor ul , Kobab Farkhanda , Ahmed Tahseen
Published: March 2021

Introduction: Severe Acute Respiratory Syndrome is group of viral disease associated with respiratory infection and it has similar symptoms of COVID-pandemic. The first case of SARS was reported in ancient remote areas of China in 2003 and spread throughout the world within short period of time. World Health Organization coordinated with numerous health experts around the globe in order to overcome the pandemic condition.

Methodology: The descriptive cross-sectional study was conducted for the period of 06 months from June 2020 to December 2020 at different medical universities of Sindh province. Total 374 study samples were selected and data was collected from the medical students of numerous medical universities of Sindh province and well designated questionnaire was filled by all participants through proper guidelines provided to them. Data was analyzed by using statistical software SPSS version 24.00.

Results: Impact of Covid Pandemic on the mental health of medical students was evaluated by compiling the data from questionnaire filled by them. Frequency of males were 216(%) and females 158(%), mostly people were resident of rural areas with the frequencies of 226 (%) and only 148(%) belongs to urban areas. 114 participants belongs to MBBS degree, 49 belongs to BDS, 72 Nursing, 83 Pharmacy and 56 students belongs to Public Health department of numerous medical universities.

Conclusion: It was concluded that there was bad impact of Covid-19 pandemic on the mental health of medical students of Universities from Sindh province. Level of anxiety among the students totally depends upon variables were online classis, examination, ward visits and Assignments. Academic activities along with financial matter had direct impact on the mental health of students.
Study on Total Phenolic, Flavonoid and Antioxidant Capacity of Fish Singgang Extracts
Authors: Jamain Anis Nafisah , Ridzwan Norhaslinda , Jumli Mimie Noratiqah , Hadi Norhayati Abd , Rohin Mohd Adzim Khalili , Arshad Roslan , Bakar Che Abdullah Abu , Latif Ahmad Zubaidi A.
Published: March 2021

Aim: To evaluate the ash and moisture contents, total phenolic content, total flavonoid content, and antioxidant potential of Terengganu singgang extracts.

Study Design: Experimental study.

Place and Duration of Study: Central Laboratory, Tissue Culture Laboratory, Universiti Sultan Zainal Abidin, Terengganu between April 2019 and July 2019.

Methodology: Samples comprised three types of singgang dishes, which were prepared, cooked, and then extracted with distilled water and ethanol (EtOH) in different strengths, 50%, 70%, and 100%. These singgang samples were chub mackerel (ST), Indian mackerel (SK), and a control sample with no fish(SC). Extracts were analyzed for their moisture and ash content. Also, the total phenolic content (TPC) was assayed using Folin-Ciocalteu reagent, while total flavonoid content (TFC) using AlCl3 colorimetric assay, and antioxidant activity using 1,1-Diphenyl-2-picrylhydrazyl (DPPH). The total antioxidant capacity (T-AOC) was also evaluated.

Results: Experimental assays showed that the SC sample extracted in 100% EtOH produced the highest yield (3.7%). SK samples were lower than SC and ST in moisture content and ash content with 94.21%, 96.37% and 93.03% moisture content and 0.85%, 0.71%, and 0.96% ash content. Meanwhile, the extract of ST in 100% EtOH yielded the highest TPC (315.0 mg GAE/100g) and T-AC (8.8 U/mL) but the lowest in DPPH scavenging activity (12.2%). On the other hand, the extract of SK in 70% EtOH gave the highest TFC with 6485.3 mg QE/100g. The correlation of TFC and TPC with DPPH and T-AOC assays was positively significant.

Conclusion: In conclusion, the ST extract yielded the best antioxidant capacity.
Sodium Dodecylbenzene Sulfonate-Modified Biochar as An Adsorbent for The Removal of Methylene Blue
Authors: Anas Argo Khoirul , Pratama Sandy Yudha , Izzah Aqidatul , Kurniawan Muhammad Arsyik
Published: March 2021

Biochar is an interesting adsorbent material due to its use is correlated with biomass waste utilization and also minimize environmental pollution from high amount of biomass by-product. Regarding to improve the biochar ability in water treatment, several surface modifications have been developed, one of them is modification using surfactant. In this study, sodium dodecylbenzene sulfonate (SDBS) was used to modify the surface of biochar prepared from pyrolysis of cassava peels (Manihot utilissima). Its performance in biochar modification to remove methylene blue (MB) dyes was compared with sodium dodecyl sulphate (SDS) surfactant for observing the important of – interactions mechanisms. The analysis of biochar and biochar-SDBS were conducted by using Fourier transform infrared (FTIR), CHNS elemental analysis, and scanning electron microscope (SEM). Furthermore, the adsorption experiments were conducted using UV-Vis spectrophotometer. It is known that modification using SDBS could increase the adsorption capacity of biochar not only from electrostatic interaction but also through – interactions mechanisms. In this respect, as the amount of SDBS mass increased, the adsorption capacity was also improved due to the modification produced more active cites on biochar. The maximum MB adsorption onto biochar-SDBS occurred at adsorbent mass of 15 mg with optimum pH value of 10. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).
Mountain Glaciation
Authors: Stroeven Arjen P. , Blomdin Robin
Published: March 2021

The Quaternary is characterized by long periods of glacier and ice sheet growth (glaciations) interspersed with short periods of glacier retreat and ice sheet decay (interglaciations). Glaciers form preferentially in high‐altitude and high‐latitude locations owing to low mean annual temperatures. Most of the world's high mountain ranges have therefore hosted glaciers during the Quaternary and have characteristic and often spectacular glacial erosional landforms. Glaciers continue to be critical infrastructural elements as a reliable source of fresh water for many downstream communities.
Nuclear Landforms
Authors: Butler David R.
Published: March 2021

Detonation of nuclear explosives creates depressions and craters on the landscape that vary in size depending on whether the explosion was above or below ground and on the strength of the explosion. Nuclear explosions also produce radioactive glass particles first identified after the world's first nuclear explosion, at the Trinity Site in New Mexico, USA, on July 16, 1945. All nuclear landforms are a form of anthropogeomorphology, and all such features were created on or postdate July 16, 1945.
Mental Health, Geography, and the Academy
Authors: Mullings Beverley , Parizeau Kate , Peake Linda
Published: March 2021

The presence of mental health issues in the Western academy is increasingly hard to avoid, as the stress of academic life takes its toll on the mental health of its members and practices of academic knowledge production. This entry addresses why we need to think about mental health, what we know about experiences of mental health in the academy, and what is being done by geographers and others. As a discipline, geography has not been the first to address the mental health concerns of is practitioners, both students and faculty members, but it is increasingly at the forefront in taking its toll seriously. Not least among these efforts has been the establishment of the American Association of Geographers (AAG) Task Force on Mental Health and, subsequently, an AAG Affinity Group on Mental Health in the Academy.
Food Environments
Authors: Widener Michael J. , Liu Bochu
Published: March 2021

The food environment is a term used to describe the geographies of food in the built environment. A variety of methods have been used to describe food environments and analyze their associations with socioeconomic characteristics, food purchasing and consumption behaviors, and health outcomes. While spatial patterns in food environments are consistently identified, their relationships with the aforementioned variables remain unclear. Future directions for research in this area include improving measurements of access and exposure to food environments to account for complex human behaviors and addressing limitations in analyses due to data collection and study design.
Nuclear Geographies and Nuclear Issues
Authors: Alexis‐Martin Becky , Turnbull Jonathon , Bennett Luke , Bolton Matthew , Davies Thom , Dunlop Gair , Hawkins Dimity , Hogue Rebecca H. , Holloway Philippa , Malin Stephanie A. , Mangioni Talei Luscia , Mayoux Chloe , McClelland Gwyn , Meyer Teva , slavick elin o'Hara , Ross Linda
Published: March 2021

Nuclear geographies and geographers contemplate the significance of nuclear technologies and issues for humans, nonhumans, and ecologies in the past, present, and future. This definition highlights how radiation interacts across different scales and mobilities by considering the significance of their relations to humans, nonhumans, ecologies, and materialities. The field brings together diverse geographical approaches to understand nuclear medicine, warfare, energy, and other nuclear technologies. With its focus on social, political, cultural, economic, and ecological consequences, nuclear geographies trace the way that nuclear legacies intersect with contemporary and future challenges. While a process of decolonization of knowledge has begun, more work is needed to highlight how and why the benefits and risks of nuclear technologies are unevenly distributed across lines of race, class, and gender, presenting threats to vulnerable human and nonhuman communities and perpetuating spatial inequalities. This definition provides a toolkit with which to approach key themes – landscapes, zones, and communities; materialities, culture, and the more‐than‐human; politics, activism, and postcolonialism – and with which to consider future directions.
Posturbanity
Authors: Tsutsumi Kenji
Published: March 2021

Since the last quarter of the twentieth century, we have begun to observe the features of newer posturban situations at several points, generated from the integration of the knowledge economy and globalization. Through the era of counterurbanization and reurbanization, the urban structure consisting of loop, inner city, main urban area, suburbs, and hinterlands has been clearly changed. Compactization of cities, higher density in the suburbs, and the decay of relations between cities and hinterlands may occur in posturbanity. In developed countries, knowledge societies have already started to change from content‐oriented perspectives to context‐oriented ones. In the near future of Society 5.0 and Industry 4.0, and after the postpandemic (postcoronavirus) era, urbanity will continue to change within the scheme of posturbanity and beyond. The concept is critical and essential for thinking about urbanity in the present and near future.
Dynamical system learning using extreme learning machines with safety and stability guarantees
Authors: Salehi Iman , Rotithor Ghananeel , Yao Gang , Dani Ashwin P.
Published: March 2021

This article presents a continuous dynamical system model learning methodology that can be used to generate reference trajectories for the autonomous systems to follow, such that these trajectories are invariant to a given closed set and uniformly ultimately bounded with respect to an equilibrium point inside the closed set. The autonomous system dynamics are approximated using extreme learning machines (ELM), the parameters of which are learned subject to the safety constraints expressed using a reciprocal barrier function, and the stability constraints derived using a Lyapunov analysis in the presence of the ELM reconstruction error. This formulation leads to solving a constrained quadratic program (QP) that includes a finite number of decision variables with an infinite number of constraints. Theorems are developed to relax the QP with infinite number of constraints to a QP with a finite number of constraints which can be practically implemented using a QP solver. In addition, an active sampling methodology is developed that further reduced the number of required constraints for the QP by only evaluating the constraints at a smaller subset of points. The proposed method is validated using a motion reproduction task on a seven degree‐of‐freedom Baxter robot, where the task space position and velocity dynamics are learned using the presented methodology.
Biomass‐Derived P, N Self‐Doped Hard Carbon as Bifunctional Oxygen Electrocatalyst and Anode Material for Seawater Batteries
Authors: Kim Jioh , Park Jinkyu , Lee Jisung , Lim Won‐Gwang , Jo Changshin , Lee Jinwoo
Published: March 2021

Owing to the demand for low‐cost batteries with safety, Na‐seawater batteries (SWBs) have received considerable attention as a new energy storage system (ESS). In SWB, it is necessary to use an advanced oxygen evolution/reduction reaction (OER/ORR) catalyst for high energy efficiency (EE) in the cathode and a good sodium storage material for a highly reversible capacity in the anode part. In this study, nanostructured and N and P dual‐doped hard carbon is fabricated by simply carbonizing abundant biomass, pine pollen. The oxygen electrocatalytic performance of pine pollen carbon (PPC) for a cathode is confirmed by a seawater half‐cell test, which exhibits the lowest overpotential reported among Pt/C (20 wt%) and commercial hard carbon (HC) electrodes. The sodium‐storage performance of PPC as an anode active material is tested using a coin‐type Na half‐cell, which exhibits a higher reversible capacity than that of the HC electrode. To reduce the manufacturing cost, this SWB, comprising both PPC electrodes at the anode and cathode, are fabricated and shown an EE of 74% and a coulombic efficiency (CE) of 98%. This study proposes a low‐cost and safe ESS system by utilizing seawater as catholyte, bifunctional (OER/ORR, sodiation/desodiation) electrode configuration, and abundantly available biomass carbon.
Imide‐Functionalized Triarylamine‐Based Donor‐Acceptor Polymers as Hole Transporting Layers for High‐Performance Inverted Perovskite Solar Cells
Authors: Li Bolin , Yang Kun , Liao Qiaogan , Wang Yang , Su Mengyao , Li Yongchun , Shi Yongqiang , Feng Xiyuan , Huang Jiachen , Sun Huiliang , Guo Xugang
Published: March 2021

Dopant‐free hole‐transporting layers (HTLs) are highly desired for realizing efficient and stable perovskite solar cells (PVSCs), but only very few of them can enable power conversion efficiencies (PCEs) over 20%. Herein, two imide‐functionalized triarylamine‐based donor‐acceptor (D‐A) type copolymers, PBTI‐TPA and PTTI‐TPA, are developed and applied as dopant‐free HTLs in inverted PVSCs. The combination of a classic redox‐active triphenylamine donor unit and an electron‐withdrawing oligothiophene imide co‐unit with rigid and planar backbone furnishes the two polymers with quasi‐planar backbone, suitable frontier molecular orbital (FMO) energy levels, favorable thermal stability, appropriate film morphology, and passivation effect. More importantly, the greatly improved hole mobility renders them as promising HTLs for PVSCs. As a result, the undoped PTTI‐TPA‐based inverted PVSCs deliver a remarkable PCE up to 21% as well as negligible hysteresis and substantial long‐term stability, outperforming the devices based on PBTI‐TPA and PTAA. The performance also represents one of the highest PCEs reported to date for PVSCs based on dopant‐free polymeric HTLs. The results highlight the great potentials of oligothiophene imides for constructing donor‐acceptor polymeric HTLs for enabling high‐performance dopant‐free PVSCs.
Excitonic Nature of the Band‐Edge Absorptions in Borate Nonlinear Optical Materials
Authors: Li Rukang K.
Published: March 2021

Borate crystals are widely applied in solid‐state laser systems for their superior properties of wide transparency range, large nonlinear optical (NLO) coefficients, and high resistance to laser damage. Previous theoretical studies all reference the bandgaps to the UV absorption cut‐offs. Herein, through the calculated band structures of three widely applied borate NLO crystals, namely, β‐BaB2O4 (BBO), LiB3O5 (LBO), and KBe2BO3F2 (KBBF), it is found that the bandgaps are always much wider than the absorption cut‐offs by over at least 1 eV. Therefore, an excitonic mechanism is proposed for the band‐edge absorptions. From the detailed band structures of the frontier orbitals, with a Wannier−Mott type approximation to the excitons, and reduced screening from lowered effective dielectric constants, the binding energies of the excitons in the three mentioned borate crystals are obtained. It is found that the absorption cut‐offs agree with the transition energies of the excitons very well for all the three crystals. The implication of these findings helps to find ways of the absorption decrease and laser damage prevention of those crystals.
p‐Menthadienes as Biorenewable Feedstocks for a Monoterpene‐Based Biorefinery
Authors: Tibbetts Joshua D. , Bull Steven D.
Published: March 2021

A terpene‐based biorefinery is described that uses crude sulfate turpentine (CST) and gum turpentine (GT) to produce mixtures of p‐menthadienes (p‐MeDs) as biorenewable terpene feedstocks. An acid catalyzed ring opening reaction (6 m aq. H2SO4, 90 °C) is first used to convert the major bicyclic monoterpenes (α‐pinene, β‐pinene, and 3‐carene) in untreated CST (or GT with 5 mol% Me2S) into mixtures of monocyclic p‐MeDs. These unpurified sulfurous p‐MeD mixtures (α‐terpinene, γ‐terpinene, and isoterpinolene) are then used as feedstocks for oxidative aromatization (OA), ozonolysis, Diels–Alder, and hydrogenation reactions to produce p‐cymene, fragrances, anti‐oxidants, drugs, biopolymers, and biofuels. Mechanistic studies of the OA reaction used to convert the p‐MeDs into p‐cymene reveal that p‐cymene hydroperoxide acts as an initiator to produce polar radical intermediates that are stabilized by DMSO generated in situ through aerobic oxidation of Me2S. This enables CST and GT to be converted into biorenewable p‐cymene in 50–60% yields (two steps) using a process that only requires aqueous acid, oxygen, heat, and a final distillation step.
Solar Harvesting through Multilayer Spectral Selective Iron Oxide and Porphyrin Transparent Thin Films for Photothermal Energy Generation
Authors: Lyu Mengyao , Lin Jou , Krupczak John , Shi Donglu
Published: March 2021

A fundamental challenge in energy sustainability is efficient utilization of solar energy towards energy‐neutral systems. The current solar cell technologies have been most widely employed to achieve this goal, but are limited to a single‐layer 2D surface. To harvest solar light more efficiently, a multilayer system capable of harvesting solar light in a cuboid through transparent photothermal thin films of iron oxide and a porphyrin compound is developed. Analogous to a multilayer capacitor, an array of transparent, spectral selective, photothermal thin films allows white light to penetrate them, not only collecting photon energy in a 3D space, but generating sufficient heat on each layer with significantly increased total surface area. In this fashion, thermal energy is generated via a multilayer photothermal system that functions as an efficient solar collector, energy converter and generator with high energy density. A solar‐activated thermal energy generator that can produce heat without any power supply and reach a maximum temperature of 76.1 °C is constructed. With a constant incoming white light (0.4 W cm−2), the thermal energy generated can be amplified 12‐fold via multilayers. The multilayer system extends another dimension in solar harvesting and paves a new path to energy generation for the energy‐neutral system.
Collective Magnetism in 2D Polymer Made of C‐Doped Triangular Boron Nitride Nanoflakes
Authors: Anindya Khalid N. , Rochefort Alain
Published: March 2021

The electronic and magnetic properties of 2D polymer built from triangular boron nitride monomers (tBN) doped with C atom are investigated with first‐principles DFT calculations. Polymers made of pure tBN are insulators as pristine h‐BN, but substituting the central B(N) by C atom in tBN(NB) spontaneously leads to the creation of a spin‐polarized ground state polymer. Moreover, the ground state of C‐doped polymer is an open‐shell semiconductor in which both Dirac and flat bands coexist nearby Fermi level while the nearest excited state is a closed‐shell semi‐metal where the Dirac cone crossed Fermi level. The triangular shape of the monomer, the nature of atomic substitution, and the relative position of C‐dopant among the 2D polymer are contributing to create a strong collective magnetism in conjunction with a significant orbital overlap between C‐dopants separated by 1.0 nm. This collective magnetism is totally suppressed in (CtBN‐CtNB) copolymer arrangement, where the material shows a semiconducting gap with no spin‐polarization and strongly localized states around Fermi level. The results predict a 2D material with long range metal free magnetic ordering, in conjunction with high carrier mobilities from Dirac bands and anisotropic shapes of topological states, that opens the door for 2D organic spintronic applications.
Imbalanced Learning with Oversampling based on Classification Contribution Degree
Authors: Jiang Zhenhao , Yang Jie , Liu Yan
Published: March 2021

Imbalanced datasets exist commonly in the real world, which leads to poor performance of general machine learning models because of skewed class distribution. To address the data‐imbalance problem, a novel oversampling method based on classification contribution degree, called OS‐CCD is presented. First a new concept, classification contribution degree, is established based on micro and macro information extracted from raw datasets. With the classification contribution degree, OS‐CCD enables positive samples near the class boundary and located in an area with high density of positive samples to generate more synthetic samples than others. Furthermore, the neighbor selection for oversampling is no longer random but in the light of a selected probability. Experimental results on 12 benchmark datasets substantiate that four commonly used classifiers with the oversampling method outperform those with six popular oversampling methods in terms of accuracy, F1‐score and AUC.
Molten NaCl‐Assisted Synthesis of Porous Fe‐N‐C Electrocatalysts with a High Density of Catalytically Accessible FeN4 Active Sites and Outstanding Oxygen Reduction Reaction Performance
Authors: Wang Qing , Yang Yuqi , Sun Fanfei , Chen Guangbo , Wang Jian , Peng Lishan , Chen Wan‐Ting , Shang Lu , Zhao Jiaqi , Sun‐Waterhouse Dongxiao , Zhang Tierui , Waterhouse Geoffrey I. N.
Published: March 2021

Iron single atom catalysts (FeN4) hosted in the micropores of N‐doped carbons offer excellent performance for the oxygen reduction reaction (ORR). Achieving a high density of FeN4 sites accessible for ORR has proved challenging to date. Herein, a simple surface NaCl‐assisted method towards microporous N‐doped carbon electrocatalysts with an abundance of catalytically accessible FeN4 sites is reported. Powder mixtures of microporous zeolitic imidazolate framework‐8 and NaCl are first heated to 1000 °C in N2, with the melting of NaCl above 800 °C creating a highly porous N‐doped carbon product (NC‐NaCl). Ferric (Fe3+) ions are then adsorbed onto NC‐NaCl, with a second pyrolysis stage at 900 °C in N2 yielding a porous Fe/NC‐NaCl electrocatalyst (Brunauer–Emmett–Teller surface area, 1911 m2 g−1) with an excellent dispersion and high density of accessible surface FeN4 sites (26.3 × 1019 sites g−1). The Fe/NC‐NaCl electrocatalyst exhibits outstanding ORR performance with a high half‐wave potential of 0.832 V (vs reversible hydrogen electrode) in 0.1 m HClO4. When used as the ORR cathode catalyst in a 1.0 bar H2‐O2 fuel cell, Fe/NC‐NaCl offers a high peak power density of 0.89 W cm−2, ranking it as one of the most active M‐N‐C materials reported to date.
Early radiographic pneumoconiosis is associated with impaired exercise gas exchange among coal miners with normal resting spirometry
Authors: Gandhi Sheiphali A. , Cohen Robert A. , Blanc Paul D. , Go Leonard H. T.
Published: March 2021

Rationale

We sought to determine if radiographic pneumoconiosis predicts abnormal gas exchange during exercise in coal mine workers with preserved resting lung function.

Methods

We analyzed data from former coal miners seen between 2006 and 2014 in a single clinic specializing in black lung evaluations. We limited the analysis to those with normal resting spirometry and an A‐a gradient at peak exercise ≥10 mmHg. We used multivariable logistic regression to estimate predictors of A‐a gradient widened to >150% of the reference value. We focused on chest radiographs consistent with pneumoconiosis, taking into account higher silica exposure mining activities and years underground, and adjusting for cigarette smoking, obesity, and coronary artery disease.

Results

Of 5507 miners, we analyzed data for 742 subjects with normal spirometry and all key clinical variables available, of whom 372 (50.1%) had radiographic evidence of pneumoconiosis. All but 21 had small opacity profusion of less than 2/1. The median A‐a gradient at peak exercise was 108% of reference value (interquartile range, 81%–141%). In the multivariable analysis, radiographic pneumoconiosis was associated with increased odds of widened A‐a gradient (odds ratio [OR], 2.47; 95% confidence interval [CI], 1.7–3.7). Limited to 660 subjects with normal diffusing capacity for carbon monoxide, the odds were similarly increased (OR, 3.20; 95% CI, 1.5–3.6).

Discussion

Among coal miners with preserved resting lung function, radiographic evidence of early pneumoconiosis more than doubled the odds of abnormal exercise physiology. Impairment in pneumoconiosis occurs in early disease and may only be evident on exercise testing.
Genotype and phenotype in 18 Chinese patients with Coffin‐Siris syndrome
Authors: Cheng Shirley S. W. , Luk Ho‐Ming , Mok Myth Tsz‐Shun , Leung Sha‐Sha , Lo Ivan F. M.
Published: March 2021

Coffin‐Siris syndrome (CSS, MIM# 1359200) is a multisystem congenital disorder characterized by coarse facial features, hypoplasia of the fifth digits and nails, and intellectual disability. It is a genetically heterogeneous condition caused by pathogenic variants in genes encoding proteins of the BAF (BRG1‐associated factors) chromatin modeling complex and its downstream transcriptional factor. To date over 220 CSS individuals with pathogenic variants found have been described in the literature. This case series reported 18 molecularly confirmed Chinese individuals (17 with ARIDIB (OMIM*614556) variants and one with SMARCB1 (OMIM*601607) variant) from 17 unrelated families in Hong Kong. The clinical features of these 18 Chinese CSS patients together with two previously reported Chinese patients with ARID1B variants were reviewed. Among the 19 Chinese patients with ARID1B variants, our data suggested a lower prevalence of feeding problem, autistic features, agenesis of corpus callosum (ACC) or partial/hypoplasia of corpus callosum, and sparse hair when compared with previous reports. There was appearing higher prevalence of digital hypoplasia. Digital hypoplasia was observed to become less noticeable with time in some patients. This report highlighted the age‐dependent phenotypic presentation of CSS and ethnicity‐related effect on ARID1B‐CSS phenotype. Moreover, this series included the first family with molecularly confirmed maternal somatic mosaicism of ARID1B variant leading to familial CSS recurrence.
State‐of‐the‐art methods for the treatment of severe hemorrhagic trauma: selective aortic arch perfusion and emergency preservation and resuscitation—what is next?
Authors: Iida Atsuyoshi , Naito Hiromichi , Nojima Tsuyoshi , Yumoto Tetsuya , Yamada Taihei , Fujisaki Noritomo , Nakao Atsunori , Mikane Takeshi
Published: March 2021

Trauma is a primary cause of death globally, with non‐compressible torso hemorrhage constituting an important part of “potentially survivable trauma death.” Resuscitative endovascular balloon occlusion of the aorta has become a popular alternative to aortic cross‐clamping under emergent thoracotomy for non‐compressible torso hemorrhage in recent years, however, it alone does not improve the survival rate of patients with severe shock or traumatic cardiac arrest from non‐compressible torso hemorrhage. Development of novel advanced maneuvers is essential to improve these patients’ survival, and research on promising methods such as selective aortic arch perfusion and emergency preservation and resuscitation is ongoing. This review aimed to provide physicians in charge of severe trauma cases with a broad understanding of these novel therapeutic approaches to manage patients with severe hemorrhagic trauma, which may allow them to develop lifesaving strategies for exsanguinating trauma patients. Although there are still hurdles to overcome before their clinical application, promising research on these novel strategies is in progress, and ongoing development of synthetic red blood cells and techniques that reduce ischemia‐reperfusion injury may further maximize their effects. Both continuous proof‐of‐concept studies and translational clinical evaluations are necessary to clinically apply these hemostasis approaches to trauma patients.
Imaging the Efficiency of Poly(3,4‐ethylenedioxythiophene) Doped with Acid‐Functionalized Carbon Nanotube and Iridium Oxide Electrode Coatings for Microstimulation
Authors: Zheng Xin S. , Yang Qianru , Vazquez Alberto L. , Tracy Cui Xinyan
Published: March 2021

Electrical microstimulation has shown promise in restoring neural deficits in humans. Electrodes coated with materials like the conducting polymer poly(3,4‐ethylenedioxythiophene) doped with acid‐functionalized carbon nanotubes (PEDOT/CNTs, or PC) exhibit superior charge injection than traditional metals like platinum. However, the stimulation performance of PC remains to be fully characterized. Advanced imaging techniques and transgenic tools allow for real‐time observations of neural activity in vivo. Herein, microelectrodes coated with PC and iridium oxide (IrOx) (a commonly used high‐charge‐injection material) are implanted in GCaMP6s mice and electrical stimulation is applied while imaging neuronal calcium responses. Results show that PC‐coated electrodes stimulate more intense and broader GCaMP responses than IrOx. Two‐photon microscopy reveals that PC‐coated electrodes activate significantly more neuronal soma and neuropil than IrOx‐coated electrodes in constant‐voltage stimulation and significantly more neuronal soma in constant‐current stimulation. Furthermore, with the same injected charge, both materials activate more spatially confined neural elements with shorter pulses than longer pulses, providing a means to tune stimulation selectivity. Finite element analyses reveal that the PC coating creates a denser and nonuniform electric field, increasing the likelihood of activating nearby neural elements. PC coating can significantly improve energy efficiency for electrical stimulation applications.
Organic Electrochemistry: Expanding the Scope of Paired Reactions
Authors: Wu Tiandi , Moeller Kevin D.
Published: March 2021

Paired electrochemical reactions allow the optimization of both atom and energy economy of oxidation and reduction reactions. While many paired electrochemical reactions take advantage of perfectly matched reactions at the anode and cathode, this matching of substrates is not necessary. In constant current electrolysis, the potential at both electrodes adjusts to the substrates in solution. In principle, any oxidation reaction can be paired with any reduction reaction. Various oxidation reactions conducted on the anodic side of the electrolysis were paired with the generation and use of hydrogen gas at the cathode, showing the generality of the anodic process in a paired electrolysis and how the auxiliary reaction required for the oxidation could be used to generate a substrate for a non‐electrolysis reaction. This is combined with variations on the cathodic side of the electrolysis to complete the picture and illustrate how oxidation and reduction reactions can be combined.
Integrating a Concentration Gradient Generator and a Single‐Cell Trapper Array for High‐Throughput Screening the Bioeffects of Nanomaterials
Authors: Liu Xiaoyan , Jia Yuexiao , Han Ziwei , Hou Qinghong , Zhang Wei , Zheng Wenfu , Jiang Xingyu
Published: March 2021

We herein develop a concentration gradient generator (CGG) on a microfluidic chip for diluting different nanoparticles. Specifically designed compact disk (CD)‐shaped microchannels in the CGG module could thoroughly mix the flowing solutions and generate a linear concentration gradient of nanoparticles without aggregation. We combine the CGG with a single‐cell trapper array (SCA) on microfluidics to evaluate the concentration‐dependent bioeffects of the nanoparticles. The precise control of the spatiotemporal generation of nanoparticle concentration on the CGG module and the single‐cell‐level monitoring of the cell behaviors on the SCA module by a high‐content system in real time, render the CGG‐SCA system a highly precise platform, which can exclude the average effect of cell population and reflect the response of individual cells to the gradient concentrations accurately. In addition, the CGG‐SCA system provides an automated platform for high‐throughput screening of nanomedicines with high precision and low sample consumption.
Ferrocene‐Based Metal–Organic Framework Nanosheets as a Robust Oxygen Evolution Catalyst
Authors: Liang Jing , Gao Xutao , Guo Biao , Ding Yu , Yan Jiawei , Guo Zhengxiao , Tse Edmund C. M. , Liu Jinxuan
Published: March 2021

We report the synthesis of two‐dimensional metal–organic frameworks (MOFs) on nickel foam (NF) by assembling nickel chloride hexahydrate and 1,1′‐ferrocenedicarboxylic acid (NiFc‐MOF/NF). The NiFc‐MOF/NF exhibits superior oxygen evolution reaction (OER) performance with an overpotential of 195 mV and 241 mV at 10 and 100 mA cm−2, respectively under alkaline conditions. Electrochemical results demonstrate that the superb OER performance originates from the ferrocene units that serve as efficient electron transfer intermediates. Density functional theory calculations reveal that the ferrocene units within the MOF crystalline structure enhance the overall electron transfer capacity, thereby leading to a theoretical overpotential of 0.52 eV, which is lower than that (0.81 eV) of the state‐of‐the‐art NiFe double hydroxides.
Dual Gate‐Controlled Therapeutics for Overcoming Bacterium‐Induced Drug Resistance and Potentiating Cancer Immunotherapy
Authors: Zhang Xiaodong , Chen Xiaokai , Guo Yuxin , Gao Ge , Wang Dongdong , Wu Yinglong , Liu Jiawei , Liang Gaolin , Zhao Yanli , Wu Fu‐Gen
Published: March 2021

The presence of bacteria in the tumor can cause cancer resistance to chemotherapeutics. To fight against bacterium‐induced drug resistance, herein we design self‐traceable nanoreservoirs that are simultaneously loaded with gemcitabine (an anticancer drug) and ciprofloxacin (an antibiotic) and are decorated with hyaluronic acid for active tumor targeting. The nanoreservoirs have a pH‐sensitive gate and an enzyme‐responsive gate that can be opened in the acidic and hyaluronidase‐abundant tumor microenvironment to control drug release rates. Moreover, the nanoreservoirs can specifically target the tumor regions without eliciting evident toxicity to normal tissues, kill the intratumoral bacteria, and inhibit the tumor growth even in the presence of the bacteria. Unexpectedly, the nanoreservoirs can activate T cell‐mediated immune responses through promoting antigen‐presenting dendritic cell maturation and depleting immunosuppressive myeloid‐derived suppressor cells in bacterium‐infected tumors.
Local Deuteration Enables NMR Observation of Methyl Groups in Proteins from Eukaryotic and Cell‐Free Expression Systems
Authors: Dubey Abhinav , Stoyanov Nikolay , Viennet Thibault , Chhabra Sandeep , Elter Shantha , Borggräfe Jan , Viegas Aldino , Nowak Radosław P. , Burdzhiev Nikola , Petrov Ognyan , Fischer Eric S. , Etzkorn Manuel , Gelev Vladimir , Arthanari Haribabu
Published: March 2021

Therapeutically relevant proteins such as GPCRs, antibodies and kinases face clear limitations in NMR studies due to the challenges in site‐specific isotope labeling and deuteration in eukaryotic expression systems. Here we describe an efficient and simple method to observe the methyl groups of leucine residues in proteins expressed in bacterial, eukaryotic or cell‐free expression systems without modification of the expression protocol. The method relies on simple stereo‐selective 13C‐labeling and deuteration of leucine that alleviates the need for additional deuteration of the protein. The spectroscopic benefits of “local” deuteration are examined in detail through Forbidden Coherence Transfer (FCT) experiments and simulations. The utility of this labeling method is demonstrated in the cell‐free synthesis of bacteriorhodopsin and in the insect‐cell expression of the RRM2 domain of human RBM39.
Truly Monodisperse Molecular Nanoparticles of Cerium Dioxide of 2.4 nm dimensions: A {Ce100O167} Cluster
Authors: Russell‐Webster Bradley , Lopez‐Nieto Javi , Abboud Khalil A. , Christou George
Published: March 2021

Ultra‐small nanoparticles of CeO2 obtained in molecular form, so‐called molecular nanoparticles, have been limited to date to a family whose largest member is of nuclearity Ce40 with a {Ce40O58} core atom count. Herein we report that a synthetic procedure has been developed to the cation [Ce100O149(OH)18(O2CPh)60(PhCO2H)12(H2O)20]16+, a member with a much higher Ce100 nuclearity and a {Ce100O167} core that is more akin to the smallest ceria nanoparticles. Its crystal structure reveals it to possess a 2.4 nm size and high D2d symmetry, and it has also allowed identification of core surface features including facet composition, the presence and location of Ce3+and H+ (i.e. HO−) ions, and the binding modes of the ligand monolayer of benzoate, benzoic acid, and water ligands.
Detection of anti‐SARS‐CoV‐2 antibodies in dried blood spots utilizing manual or automated spot extraction and electrochemiluminescence immunoassay (ECLIA)
Authors: Knoop Andre , Geyer Hans , Lerch Oliver , Rubio Ana , Schrader Yvonne , Thevis Mario
Published: March 2021

Serological test methods to detect anti‐SARS‐CoV‐2 antibodies represent a major measure to manage the pandemic caused by the coronavirus disease 2019 (COVID‐19). In this communication, test results obtained from minimal‐invasively collected dried blood spot (DBS) specimens, which can be sampled ‘at home’ without the need of medically trained personnel, are compared to conventionally collected venous blood samples. DBS samples were prepared for analysis either manually or by a card extraction robot, and electrochemiluminescence assay (ECLIA) characteristics, assay readout values as well as stability data covering a period of more than 200 days are provided. Constant anti‐SARS‐CoV‐2 antibody readouts of quality control DBS were obtained over the entire test period using DBS specimens stored under dry and dark conditions. In addition, test results obtained from individuals tested twice within 10 months post‐infection indicated a consistent presence of antibodies.
Genipin‐crosslinking polyvinyl alcohol hollow braids degradable tissue engineering scaffolds: Manufacturing techniques and property evaluations
Authors: Jhang Jia‐Ci , Lin Jia‐Horng , Chen Yueh‐Sheng
Published: March 2021

Tissue engineering has been developed with the aim of improving the regeneration and recovery of impaired tissues and organs. Biodegraded scaffolds serve the aforementioned functions and can also be decomposed by means of metabolism. They have no biological toxicity and save patients from injuries by the second surgery, which makes biodegradable scaffolds a new development trend in the tissue engineering. In this study, the textile engineering and chemical crosslinking techniques are employed to produce biodegradable polyvinyl alcohol (PVA) hollow braids, serving as the tissue engineering scaffolds. The process involves two types of products, including the twisted yarns and hollow braids. The twist number of PVA twisted yarns is changed to form different PVA twisted yarns, which are then used to braided into hollow braids via the braiding technology. Therefore, the hollow braids are basically composed three types of PVA twisted yarns. Next, the surface observation, mechanical properties, and degradation of the products are then evaluated. The test results indicate that PVA twisted yarns exhibit the optimal mechanical properties when being twisted with 3 turns/inch. Any higher twist counts result in over twist in the twisted yarns. The optimal hollow braids are composed of PVA twisted yarns with a twist counts being 3 turns/inch. Afterwards, hollow braids are crosslinking with genipin, thereby obtaining greater mechanical strength of 23.6 N and higher decomposition rate of 0.8. The specified hollow braids are suitable for the use as tissue engineering scaffolds.