bluuebunny/crossref_metadata_2025 huggingface dataset:
Farklı Soğutucu Akışkanların Kullanıldığı Kanatlı Borulu Bir Evaporatörün Matematiksel Modeli
Authors: MANÇUHAN Ebru , MUTLU Tutku , KIRAN YILDIRIM Berçem , TİTİZ-SARGUT Sibel
Published: March 2019

Bu çalışmada farklı akışkanların soğutkan olarak
kullanıldığı kanatlı borulu kompakt ısı değiştiricisinin bir evaporatör olarak
matematiksel modellemesi yapılmıştır. Evaporatör olarak kullanılan ısı
değiştiricisinde (yüzey tipi 8.03/8T ve CF-7.0-5/8J), değişen çalışma parametrelerinde (kütlesel debi, sıcaklık,
basınç) bir
doğal (R290) ve üç sentetik (R410A, R134a, R404A) soğutucu akışkan kullanılarak soğutma kapasitesini
tahmin edebilen bir model geliştirilmiştir. Ayrıca seçilen soğutucu
akışkanların (hidro-floro karbon gruba giren R134a, R404A, R410A ve hidrokarbon
grubuna giren R290) çevreye olan etkileri küresel ısınma etkisi (GWP) değerleri
karşılaştırılarak incelenmiştir.  Matematiksel model, EES (Engineering Equation Solver)
yazılımı kullanılarak hazırlanmıştır. Geliştirilen model aynı soğutma kapasitesinde farklı
soğutucu akışkan ve yüzeyler kullanıldığı durumlar için evaporatör buharlaşma
ve kızgın gaz bölgesine giren–çıkan hava sıcaklıkları, ısı taşınım katsayısı,
toplam ısı transfer katsayıları ve ısı akısının tahmin edilebilmektedir. Değişen kütle akısı değerlerinde (50-500
kg/m².s), buharlaşma bölgesinde en yüksek ısı taşınım katsayısı doğal akışkan
R290 için hesaplanmıştır. Tüm akışkanlar karşılaştırıldığında diğer sentetik
akışkanlara göre R290’nın daha düşük kütle akısı değerine sahip olduğu
görülmüştür. Elde edilen sonuçlar ve soğutucu akışkanların çevreye olan
etkileri göz önünde bulundurulduğunda, soğutma sistemlerinde doğal akışkan
R290’nın tercih edilebileceği belirlenmiştir.
Il ruolo dell’idrogeologo: dalla raccolta dati all’interpretazione di un modello numerico
Authors: De Filippis Giovanna , Di Curzio Diego , Stevenazzi Stefania
Published: March 2019

Le attività che un idrogeologo è chiamato a svolgere richiedono molteplici competenze che possono spaziare su più discipline e sono finalizzate a fornire un’appropriata conoscenza dei fenomeni fisici e chimici che caratterizzano un sistema naturale [...].
EMERGING HAZARDOUS SUBSTANCES IN OUTDOOR AND INDOOR ENVIRONMENT. STATE OF THE ART. CURRENT AND PAST RESEARCH.
Authors: Vojinovic MILORADOV MIRJANA , Mihajlovic Ivana
Published: March 2019

The state of the art of contamination by hazardous emerging substances (HEMS) in the outdoor and indoor environment based on the original resultsof authors and key literature references is presented. History of the newly-recognized group of HEMS is described. The key physico-chemical characteristics of HEMS are emphesized, especially pseudoperzistency of HEMS, non monotonic dose response, chemical cocktails, irreversible binding to proteins, following by constants of partitioning and distribution and different forms of HEMS species in the aquatic environment (molecules, ions, cations and anions, and zwitter ions). Within this study review, representative original results of HEMS detected in the river Danube in the vicinity of Novi Sad,waste water, air and human milk are compiled, gained by numerous international and national projects, more than 30 papers published in the SCI journals and 40 full length papers printed at international and national conferences. Based on concentration levels of HEMS, for the selected HEMS, risk assessment and RQ coefficients were calculated.
Key words: emerging substances, wastewater, Danube surface water, air, human milk, risk assessment
CHALLENGES IN BIODIESEL INDUSTRY: SOCIO-ECONOMIC, OCCUPATIONAL HEALTH, AND POLICY ISSUES
Authors: AVRAMOVIĆ JELENA , VELIČKOVIĆ ANA , VELJKOVIĆ VLADA
Published: March 2019

Faced with the problem of the depletion of fossil fuels, the concern about energy security, especially in the energy depended countries due to constant conflicts in the oil-exporting countries, as well as the climate change due to burning of fossil fuels, the society recognized biofuels as the solution to many of these problems. Namely, the growing biofuel sector could provide the possibility for the development of rural areas and creating job opportunities for the local population, contribute to the development of strong self-sufficient communities and reduce the emission of greenhouse gases due to the belief that the burning of biofuels was carbon neutral. However, over the years, some issues regarding biofuel production and use emerged, showing that it was not all “black and white”, and that some side effects, such as the influence of biofuels on energy and food market, working conditions and workers’ rights regarding occupational health, the inconsistency of biofuel policies, the land change, etc. should also be addressed to.
Key words: biodiesel production, workers' rights, working conditions, occupational health and safety
Underwater sound production varies within not between species in sympatric newts
Authors: Hubáček Jiří , Šugerková Monika , Gvoždík Lumír
Published: March 2019

Sound production is a widespread phenomenon among animals. Effective sound use for mate or species recognition requires some acoustic differentiation at an individual or species level. Several species of caudate amphibians produce underwater sounds, but information about intra- and interspecific variation in their acoustic production is missing. We examined individual, sex, and species variation in underwater sound production in adults of two sympatric newt taxa, Ichthyosaura alpestris and Lissotriton vulgaris. Individual newts produced simple low- (peak frequency = 7–8 kHz) and mid-high frequency (14–17 kHz) clicks, which greatly overlap between sexes and species. Individual differences explained about 40–50% of total variation in sound parameters. These results provide foundations for further studies on the mechanisms and eco-evolutionary consequences of underwater acoustics in newts.
Potentials of Sugarcane Bagasse and Poultry Manure in the Remediation of Spent Motor Oil Contaminated Soil
Authors: Sangodoyin A. Y. , Igbode I. O.
Published: March 2019

This study sought to investigate the potential of sugarcane bagasse, poultry manure and their combination in the remediation of spent motor oil contaminated soil. About 1.5 L of spent motor oil was sprinkled on plots measuring 0.5 m x 0.5 m dimension in 12 replicate plots to simulate a major spill. Poultry dung (PD), Sugarcane bagasse (SB) and hybrid of bagasse and Poultry dung (SB - PD) were applied as organic amendments and bulking agents. The amendments were randomly administered twice within two weeks to treatment plots except the control at rate of 24tons/ha. The soil was tilled to enhance aeration and watered twice a week for 56 days. A significant decrease in Total Petroleum Hydrocarbon, TPH of 61, 53, 46 and 23% for PD, SB - PD, SB and Control plots respectively was observed. TOC and TN decreased in all the plots except the control. Soil moisture contents between 21 and 24% while soil pH within the range of 6.9 to 7.5 enhanced biodegradation process. The Total Heterotrophic Bacterial Counts (THBC) varied in all the plots while heavy metals content remained unchanged during the study. The application of these biostimulants gave promising results on hydrocarbons removal from contaminated soil.
Catalyst Screening for Conversion of Waste Polyethylentherphtalate Plastic in to Liquid Fuel
Authors: Siyoum Meskerem Tsehaye , Gabbiye Nigus
Published: March 2019

The world-wide use of PET has gradually increased from time to time. And most of the PET waste is being dumped into the environment instead of recycling. This creates serious environmental pollutions. In thermal degradation process, PET is being decomposed to liquid fuels. Conversion of recycled PET bottle into fuel through effective catalyst has been investigated as a strategy for wastes into useful energy. The main objective of this research was to screen out an effective catalyst for the conversion of PETE into liquid hydrocarbon fuel. In this study, Zinc oxide, ZnO/AC, Calcium Hydroxide (Ca (OH) 2) and Ferric oxide (Fe2o3) catalysts was used at different operation condition of temperature ranging from 400 to 500°C. The optimum liquid fuel productions from PET plastic bottle were obtained. And the significance result of the maximum temperature through the use of catalyst was enhancing to identify the most effective Catalyst with respect to oil yield.  The oil yield increase when the temperature increases within the range of temperature (400°C-500°C). It was observed that gas/liquid fuel yield significantly affected by type of catalyst and temperature. Ca (OH)2 catalyst result higher yield compared the two catalysts. Finally, during the characterization process it was categorized kerosene and crude oil; these oil were obtained by PET and PET with the combination of LDPE & HDPE respectively, and the analysis were under taken from the two types of oil samples and identified Benzene by the use of GC (Gas Chromatography).
Synthesis and Characterization of Nano-Strontium Oxide (SrO) Using Erzincan Cimin Grape (Vitis vinifera, Cimin)
Authors: Gungor Azize Alayli , Nadaroglu Hayrunnisa , Gultekin Demet Demirci
Published: March 2019

Aims: Synthesis of Strontium oxide (SrO) is very remarkable for its applications in electrodes for gas sensors, lithium-ion batteries, solar cells, doped dye-sensitive solar cells, transistors, catalyst supports, super capacitors and semiconductors. This study aims to synthesize SrO nanoparticles using a new method, as they will find important and specific uses.

Experimental Design: Synthesis of SrO nanoparticles (NPs) was planned to be obtained by bio-reduction method using the plant extract of Erzincan Cimin grape (Vitis vinifera, Cimin).

Place and Duration of Study: The experimental steps of the study were carried out in the laboratories of Atatürk University, Erzurum Vocational College, Department of Chemical and Chemical Processing Technologies.

Methodology: In this study, the synthesis of SrO NPs was made by using aqueous extract of Erzincan Cimin grape (Vitis vinifera, Cimin). Biosynthesis medium containing 0.1 M Sr(NO3)2 was added to Cimin grape extract to synthesize SrO NPs.

Results: The structural characterization of the SrO NPs that were obtained as a result of the reaction was analyzed using SEM, EDAX and FTIR techniques. Using the X-ray diffraction pattern in the study, the mean particle size was calculated to be 28.6 nm. SEM analysis revealed that particles having a porous nanostructure in 20-50 nm of size were synthesized. It was determined that the maximum absorbance of SrO nanoparticles was at 203 nm. From the experimental data, it was determined that for SrO nanoparticles, the optimum synthesis rate was reached at 90 minutes, 40°C and pH 8.

Conclusion: The newly synthesized nanomaterial is expected to find applications in many different areas thanks to its physical and chemical properties.
Prevalence of Hypertension and Diabetes Mellitus among Haemodialysis Patients at Elobied Haemodialysis Unit –West Sudan
Authors: Hamed Elfaki Abdelsalam Mohamed , Abdalla Mohamed Samia Tarig
Published: March 2019

Background and Objectives: Hypertension and diabetes mellitus are major risk factors of end – stage renal disease (ESRD). This study aimed to determine the prevalence of hypertension and diabetes mellitus among haemodialysis patients at Elobeid haemodialysis unit.

Patients and Methods: The study was a single – centre cross - sectional study including 130 patients on chronic haemodialysis in Elobeid hospital haemodialysis unit. Each patient was personally interviewed by the co-author in the haemodialysis unit using a structured questionnaire prepared by the investigators. Data collected include: socioeconomic data (gender, age, residence, and occupation), history of hypertension, diabetes mellitus, treatment of hypertension, treatment of diabetes mellitus, duration of hypertension, duration of diabetes mellitus and duration of dialysis. Hypertension was defined as blood pressure ≥ 140/90 or the use of antihypertensive medications. Diabetes mellitus is defined by use of insulin therapy. In this study both hypertension and diabetes mellitus were already diagnosed and on regular medications. Statistic package for social sciences (SPSS) version 20 was used for data analysis.

Results: One hundred and thirty patients were recruited. More than two thirds of patients were males with male to female ratio of 2.2: 1. Patient’s age ranged from 12 years to 90 years. The mean age was 46.3 ± 17.8 years. Forty (32%) patients were above 56 years of age. Ninety eight (75%) patients were hypertensive, the majority of hypertensive patients were males (90%). Eighty six hypertensive patients were on calcium channel blocker (88%). Amlodipine was the commonly used antihypertensive used. Twenty five (19%) patients were diabetics and all of them were males. All diabetic patients were also hypertensive. Fourteen diabetic patients (56%) were on insulin therapy, while 11 patients were using metformin.

Conclusion: The prevalence of hypertension among haemodialysis patients was high while the prevalence of diabetes is less than that reported globally. The blood pressure should be tidily controlled specially in diabetic patients and patients with impaired renal function. For early detection of chronic kidney disease and elevated blood pressure as a sequel, routine blood pressure measurement is highly recommended in adult patients attend the clinic for any reason.
Associated Risk Factors and Seroprevalence of Hepatitis B among Pregnant Women Attending Antenatal Clinic in a Rural Setting of Cameroon (Penka-Michel)
Authors: Mabeku Laure Brigitte Kouitcheu , Tchakounte Constantin , Flaurant Tchouangueu Thibau , Etoa Francois-Xavier
Published: March 2019

Background: Vertical transmission is an important route of transmission for hepatitis B virus infection. Despite the introduction of HBV vaccine in the extended immunization program in 2005, Cameroon has remained a hyper-endemic area. The aim of this study was to determine the seroprevalence of hepatitis B Virus among antenatal clinic attenders in Penka-Michel-Cameroon, and to identify potential risk factors associated with the infection for a better prevention of the disease.

Study Design: The study was a case control study conducted in four reference hospitals in Penka-Michel, a rural area in west region of Cameroon during April to July 2014.

Methodology: Six hundred and forty three (643) pregnant women were recruited. The DiaSpot HBsAg in vitro diagnostic test strips were first used. Positive samples were further confirmed for HBsAg, HBeAg, anti-HBs, anti-HBe and anti-HBc using an immunoassay kit. Liver enzymes (ALT, AST and ALP) were also evaluated for HBsAg positive samples using TECO DIAGNOSTICS kit.  A structured questionnaire was used to collect information on sociodemographic parameters and predisposing risk factors of hepatitis B from each patient. Data collected was analyzed using Graph Pad prism version 5.03.

Results: The prevalence of hepatitis B infection (HBsAg) in our setting was 4.7%. Fifty percent of HBsAg positive women were also HBeAg positive and 46.7% of them lack antibodies against hepatitis B e antigen. All the HBsAg positive women had previous contact with HBV and just 3.3% of them were immunized against HBV. Women in the age groups 31–35 years were significantly more affected (X2 16.95, P = .0045). Only a history of a contact with hepatitis B infection was significantly associated with HBsAg and HBeAg positivity (X2 27.45, P = .0001; X2 25.31,                 P = .0003).

Conclusion: Administration of HBIG in combination with hepatitis B vaccine as post-exposure prophylaxis for infants born to HBV infected mothers is of paramount importance. In addition, universal HBsAg screening of all pregnant women will greatly assist in reducing the maternal transmission of HBV in Cameroon.
Depletion Analysis of the Nigerian Research Reactor Fuel with 19.75% Enriched UO2 Material
Authors: Rabba J. A. , Onimisi M. Y. , Samson D. O.
Published: March 2019

The depletion analysis of the Nigerian research reactor fuel with 19.75% enriched UO2 have been performed using the VENTURE PC code. The matrix exponential method was selected in this work to perform the depletion analysis. The volume fraction of the materials in this mixture was calculated and multiplied by their respective atom densities to obtain the effective atom density of the nuclide in the water, Aluminium mix region of the fuel cell model. The plot of the variation of k infinity versus hydrogen to Uranium ratio was generated using Matlab programming language for processing of the computer code result. This shows that as the ratio of hydrogen to uranium in the core of the reactor is increased, the reactivity also increases by gradually increasing the fuel cell radii till it gets to the peak of 0.6193. Any further increment in the radius of the fuel cell radii, the reactivity of the reactor decreases as the hydrogen to uranium ratio increases.
A comparison of doctoral training in biomedicine and medicine for some UK and Scandinavian graduate programmes: learning from each other
Authors: Williams Anwen , Jones Meriel G. , Jonsson Roland , Harris Robert A. , Mulvany Michael J.
Published: March 2019

Although the historical bases for graduate training in the United Kingdom (UK) and Scandinavia both stem from the original concept developed by von Humboldt, and both award a ‘PhD degree', their paths have diverged. There are thus significant differences in the manner in which graduate training is organised. To analyse these differences, two UK graduate programmes (School of Medicine, Cardiff University; Institute of Integrative Biology, University of Liverpool) and two Scandinavian graduate schools (Faculty of Medicine and Dentistry, University of Bergen; Karolinska Institutet, Stockholm) completed a Self‐evaluation questionnaire developed by Organisation of PhD Education in Biomedicine and Health Sciences in the European System (ORPHEUS)). Analysis of the completed questionnaires shows differences concerning requirements for admission, the training content of PhD programmes, the format of the PhD thesis, how the thesis is assessed and the financial model. All programmes recognise that PhD training should prepare for employment both inside and outside of academia, with emphasis on transferable skills training. However, the analysis reveals some fundamental differences in the direction of graduate programmes in the UK and Scandinavia. In the UK, graduate programmes are directed primarily towards teaching PhD students to do research, with considerable focus on practical techniques. In Scandinavia, the focus is on managing projects and publishing papers. To some extent, the differences lead to a lack of full recognition of each other's theses as a basis for doing a postdoc. This paper describes the basis for these differences and compares the two approaches and points to areas in which there is, or might be, convergence.
Information Technology and Mobility
Authors: Schwanen Tim
Published: March 2019

The interrelations of information technology (IT) and mobility have long been of interest to geographers. A long‐standing focus on the extent to which IT use can substitute for the physical movement of people, goods, and information has been complemented by many other lines of inquiry. These concentrate on people's everyday life and transportation and on changes in mobility systems, often considering the consequences for sociospatial inequalities and broader spatial formations.
Food Security
Authors: Sage Colin
Published: March 2019

Food security has become an increasingly important, but contested, term since the global food price spike of 2008. Ongoing price volatility, linked to a range of causal drivers, has raised the stakes in formulating solutions to feeding a world that will number 9.7 billion people by 2050. In contrast to those who favor treating food security as a scientific problem requiring technical solutions that lead to greater food production are those who promote a rights‐based approach to food best represented by the food sovereignty movement. With global food production facing a range of interlocking challenges, food security has become increasingly entangled with the “sustainability” question such that new ideas and policy initiatives are emerging across the realms of production and consumption.
Persistence of Tofacitinib in the Treatment of Rheumatoid Arthritis in Open‐Label, Long‐Term Extension Studies up to 9.5 Years
Authors: Pope Janet E. , Keystone Edward , Jamal Shahin , Wang Lisy , Fallon Lara , Woolcott John , Lazariciu Irina , Chapman Douglass , Haraoui Boulos
Published: March 2019

Objective

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). This post hoc analysis evaluated tofacitinib persistence in patients with RA in long‐term extension (LTE) studies up to 9.5 years.

Methods

Data were pooled from two LTE studies: ORAL Sequel (NCT00413699) and Study A3921041 (NCT00661661). Patients received tofacitinib 5 or 10 mg twice daily (BID), as monotherapy or with background conventional synthetic disease‐modifying antirheumatic drugs. Kaplan‐Meier estimates for tofacitinib drug survival and reasons for discontinuation were evaluated. Baseline factors were analyzed as predictors of persistence.

Results

In 4967 tofacitinib‐treated patients entering LTE studies, mean (maximum) treatment duration was 3.5 (9.4) years. Median drug survival (95% confidence interval) was 4.9 (4.7, 5.1) years. Estimated 2‐ and 5‐year drug survival rates were 75.5% and 49.4%, respectively. Median drug survival was similar between the tofacitinib 5 and 10 mg BID groups, and slightly higher for patients receiving tofacitinib monotherapy versus combination therapy. Overall, 50.7% of patients discontinued tofacitinib; of these, 47.2% were due to adverse events and 7.1% for lack/loss of efficacy. An increased risk of discontinuation was associated with baseline diabetes, hypertension, negative anticyclic citrullinated peptide (anti‐CCP), negative rheumatoid factor (RF), and inadequate response to tumor necrosis factor inhibitors (TNFi‐IR).

Conclusion

Median drug survival of tofacitinib‐treated patients participating in LTE studies was approximately 5 years and was similar for tofacitinib dosed at 5 and 10 mg BID. Reduced drug survival was associated with negative anti‐CCP/RF status, TNFi‐IR, and certain comorbidities. These data support tofacitinib use for long‐term management of RA.
Metallic Glassy Thin Films: Perspective on Mechanical, Magnetic, Biomedical, and Optical Properties
Authors: Liu Suya , Cao Qingping , Zhang Dongxian , Jiang Jian‐Zhong
Published: March 2019

The recent progress of metallic glassy thin films (MGTFs) in mechanical, magnetic, biomedical, and optical fields is briefly summarized. The key factors that control the mechanical behavior of MGTFs are outlined on the basis of recent theoretical and experimental works. Special MGTFs with enhanced mechanical property like nano‐structured MGTFs, multi‐layer MGTFs, and ultra‐stable MGTFs are introduced in detail. The magnetic anisotropy and magnetic impedance (MI) effect of MGTFs are discussed. In addition, MGTFs are recently found playing an important role in some new areas, for example, for biomedical and optical components. The availability of two‐dimensional MGTFs stimulates comprehensive studies in those fields, which enhance the understanding of the correlation of structure and their mechanical, magnetic, biomedical, and optical properties, and develop the designing strategy for engineers.
Injectable Self‐Healing Antibacterial Bioactive Polypeptide‐Based Hybrid Nanosystems for Efficiently Treating Multidrug Resistant Infection, Skin‐Tumor Therapy, and Enhancing Wound Healing
Authors: Zhou Li , Xi Yuewei , Xue Yumeng , Wang Min , Liu Yanle , Guo Yi , Lei Bo
Published: March 2019

The surgical procedure in skin‐tumor therapy usually results in cutaneous defects, and multidrug‐resistant bacterial infection could cause chronic wounds. Here, for the first time, an injectable self‐healing antibacterial bioactive polypeptide‐based hybrid nanosystem is developed for treating multidrug resistant infection, skin‐tumor therapy, and wound healing. The multifunctional hydrogel is successfully prepared through incorporating monodispersed polydopamine functionalized bioactive glass nanoparticles (BGN@PDA) into an antibacterial F127‐ε‐Poly‐L‐lysine hydrogel. The nanocomposites hydrogel displays excellent self‐healing and injectable ability, as well as robust antibacterial activity, especially against multidrug‐resistant bacteria in vitro and in vivo. The nanocomposites hydrogel also demonstrates outstanding photothermal performance with (near‐infrared laser irradiation) NIR irradiation, which could effectively kill the tumor cell (>90%) and inhibit tumor growth (inhibition rate up to 94%) in a subcutaneous skin‐tumor model. In addition, the nanocomposites hydrogel effectively accelerates wound healing in vivo. These results suggest that the BGN‐based nanocomposite hydrogel is a promising candidate for skin‐tumor therapy, wound healing, and anti‐infection. This work may offer a facile strategy to prepare multifunctional bioactive hydrogels for simultaneous tumor therapy, tissue regeneration, and anti‐infection.
Multipurpose Intraperitoneal Adhesive Patches
Authors: Ryu Ji Hyun , Kim Hye Jin , Kim Kyuri , Yoon GhilSuk , Wang Younseon , Choi Gyu‐Seog , Lee Haeshin , Park Jun Seok
Published: March 2019

The intraperitoneal (IP) cavity is the largest fluid‐filled space in the body and contains important organs. Although peritoneal fluid from the abdominal cavity lubricates and allows organ motion, this fluid also effectively prevents polymeric material implantation. Anastomotic leakage after surgery has been reported but few sealing methods have been developed. Herein, a fluid‐resistant adhesive called IP patch is reported that seals intestinal neo‐anastomosis sites, preventing anastomotic leakage after colorectal surgery. The bursting pressure, which is the most important index of the degree of healing after colorectal anastomosis surgery, is measured from an IP patch applied to rats (188.3 ± 14.5 mmHg) and is highly similar to the pressure observed from normal tissue (210.2 ± 22.9 mmHg). Additionally, IP patches can act as unprecedented local drug reservoirs due to the aforementioned tissue adhesive property. Drug‐loaded IP patches successfully treated multiple‐site occurrence of small peritoneal cancerous colonies. The anticancer drug‐loaded IP patches are applied to potential risk regions for recurrent and metastasized cancer in the IP cavity after the resection of peritoneal solid tumors. Thus, the multifunctionality of IP patches can be usefully exploited as an adhesive biomaterial that works effectively in difficult‐to‐treat diseases observed in IP environments.
Piezotronic Graphene Artificial Sensory Synapse
Authors: Chen Youhui , Gao Guoyun , Zhao Jing , Zhang Huai , Yu Jinran , Yang Xixi , Zhang Qian , Zhang Wenliang , Xu Shuya , Sun Jia , Meng Yanfang , Sun Qijun
Published: March 2019

The human somatosensory system, consisting of receptors, transmitters, and synapses, functions as the medium for external mechanical stimuli perception and sensing signal delivery/processing. Developing sophisticated artificial sensory synapses with a high performance, uncomplicated fabrication process, and low power consumption is still a great challenge. Here, a piezotronic graphene artificial sensory synapse developed by integrating piezoelectric nanogenerator (PENG) with an ion gel–gated transistor is demonstrated. The piezopotential originating from PENG can efficiently power the synaptic device due to the formation of electrical double layers at the interface of the ion gel/electrode and ion gel/graphene. Meanwhile, the piezopotential coupling is capable of linking the spatiotemporal strain information (strain amplitude and duration) with the postsynaptic current. The synaptic weights can be readily modulated by the strain pulses. Typical properties of a synapse including excitation/inhibition, synaptic plasticity, and paired pulse facilitation are successfully demonstrated. The dynamic modulation of a sensory synapse is also achieved based on dual perceptual presynaptic PENGs coupling to a single postsynaptic transistor. This work provides a new insight into developing piezotronic synaptic devices in neuromorphic computing, which is of great significance in future self‐powered electronic skin with artificial intelligence, a neuromorphic interface for neurorobotics, human–robot interaction, an intelligent piezotronic transistor, etc.
Recent Progress in Power Generation from Water/Liquid Droplet Interaction with Solid Surfaces
Authors: Tang Wei , Chen Bao Dong , Wang Zhong Lin
Published: March 2019

Water covers ≈70% of the Earth's surface and it contains a tremendous amount of energy that remains unexploited. With the advance of nanotechnology, new strategies toward harnessing water energy based on new mechanisms are proposed. Here, the interaction mechanisms between a water droplet and a solid surface for harvesting energy, including water–solid contact electrification in the four basic working modes of a triboelectric nanogenerator and streaming current, are reviewed. Among them, nanogenerators based on the contact electrification show the highest output. Practical applications are also presented, such as sensing application, wearable power generation, all‐weather power generation, and blue energy solutions. At last, perspectives and opportunities for using water/liquid‐based energy are discussed.
Universal Imaging of Full Strain Tensor in 2D Crystals with Third‐Harmonic Generation
Authors: Liang Jing , Wang Jinhuan , Zhang Zhihong , Su Yingze , Guo Yi , Qiao Ruixi , Song Peizhao , Gao Peng , Zhao Yun , Jiao Qingze , Wu Shiwei , Sun Zhipei , Yu Dapeng , Liu Kaihui
Published: March 2019

Quantitatively mapping and monitoring the strain distribution in 2D materials is essential for their physical understanding and function engineering. Optical characterization methods are always appealing due to unique noninvasion and high‐throughput advantages. However, all currently available optical spectroscopic techniques have application limitation, e.g., photoluminescence spectroscopy is for direct‐bandgap semiconducting materials, Raman spectroscopy is for ones with Raman‐active and strain‐sensitive phonon modes, and second‐harmonic generation spectroscopy is only for noncentrosymmetric ones. Here, a universal methodology to measure the full strain tensor in any 2D crystalline material by polarization‐dependent third‐harmonic generation is reported. This technique utilizes the third‐order nonlinear optical response being a universal property in 2D crystals and the nonlinear susceptibility has a one‐to‐one correspondence to strain tensor via a photoelastic tensor. The photoelastic tensor of both a noncentrosymmetric D3h WS2 monolayer and a centrosymmetric D3d WS2 bilayer is successfully determined, and the strain tensor distribution in homogenously strained and randomly strained monolayer WS2 is further mapped. In addition, an atlas of photoelastic tensors to monitor the strain distribution in 2D materials belonging to all 32 crystallographic point groups is provided. This universal characterization on strain tensor should facilitate new functionality designs and accelerate device applications in 2D‐materials‐based electronic, optoelectronic, and photovoltaic devices.
Ultrathin Magnetic 2D Single‐Crystal CrSe
Authors: Zhang Yu , Chu Junwei , Yin Lei , Shifa Tofik Ahmed , Cheng Zhongzhou , Cheng Ruiqing , Wang Feng , Wen Yao , Zhan Xueying , Wang Zhenxing , He Jun
Published: March 2019

2D magnetic materials have generated an enormous amount of attention due to their unique 2D‐limited magnetism and their potential applications in spintronic devices. Recently, most of this research has focused on 2D van der Waals layered magnetic materials exfoliated from the bulk with random size and thicknesses. Controllable growth of these materials is still a great challenge. In contrast, 2D nonlayered magnetic materials have rarely been investigated, not especially regarding their preparation. CrnX (X = S, Se and Te; 0 < n < 1), a class of nonlayered transition metal dichalcogenides, has rapidly attracted extensive attention due to its abundance of structural compounds and unique magnetic properties. Herein, the controlled synthesis of ultrathin CrSe crystals, with grain size reaching the sub‐millimeter scale, on mica substrates via an ambient pressure chemical vapor deposition (CVD) method is demonstrated. A continuous CrSe film can also be achieved via precise control of the key growth parameters. Importantly, the CVD‐grown 2D CrSe crystals possess obvious ferromagnetic properties at temperatures below 280 K, which has not been observed experimentally before. This work broadens the scope of the CVD growth of 2D magnetic materials and highlights their significant application possibilities in spintronics.
Metal and Nonmetal Codoped 3D Nanoporous Graphene for Efficient Bifunctional Electrocatalysis and Rechargeable Zn–Air Batteries
Authors: Qiu Hua‐Jun , Du Peng , Hu Kailong , Gao Jiaojiao , Li Huanglong , Liu Pan , Ina Toshiaki , Ohara Koji , Ito Yoshikazu , Chen Mingwei
Published: March 2019

Developing bifunctional electrocatalysts with high activities and long durability for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is crucial toward the practical implementation of rechargeable metal–air batteries. Here, a 3D nanoporous graphene (np‐graphene) doped with both N and Ni single atoms/clusters is reported. The predoping of N by chemical vapor deposition (CVD) dramatically increases the Ni doping amount and stability. The resulting N and Ni codoped np‐graphene has excellent electrocatalytic activities for both the ORR and the OER in alkaline aqueous solutions. The synergetic effects of N and Ni dopants are revealed by density functional theory calculations. The free‐standing Ni,N codoped 3D np‐graphene shows great potential as an economical catalyst/electrode for metal–air batteries.
Vertical Organic Thin‐Film Transistors with an Anodized Permeable Base for Very Low Leakage Current
Authors: Dollinger Felix , Lim Kyung‐Geun , Li Yang , Guo Erjuan , Formánek Peter , Hübner René , Fischer Axel , Kleemann Hans , Leo Karl
Published: March 2019

The organic permeable base transistor (OPBT) is currently the fastest organic transistor with a transition frequency of 40 MHz. It relies on a thin aluminum base electrode to control the transistor current. This electrode is surrounded by a native oxide layer for passivation, currently created by oxidation in air. However, this process is not reliable and leads to large performance variations between samples, slow production, and relatively high leakage currents. Here, for the first time it is demonstrated that electrochemical anodization can be conveniently employed for the fabrication of high‐performance OPBTs with vastly reduced leakage currents and more controlled process parameters. Very large transmission factors of 99.9996% are achieved, while excellent on/off ratios of 5 × 105 and high on‐currents greater than 300 mA cm−2 show that the C60 semiconductor layer can withstand the electrochemical anodization. These results make anodization an intriguing option for innovative organic transistor design.
A Potential Amphiprotic Sponge with a Controlled Release Characteristic of Protons on Demand for Oil/Water Separation and Acid/Base Neutralization
Authors: Kaang Byung Kwon , Lee Yo Seph , Han Nara , Choi Won San
Published: March 2019

Ultralight sponges with the ability to release protons on demand, namely, superhydrophobic melamine formaldehyde sponges (SHpho‐MFSs), which are characterized as being safe‐to‐handle, convenient‐to‐use, easy‐to‐store, easy‐to‐carry, and easy‐to‐collect, are switched from superhydrophilic MFSs (SHphi‐MFSs) by a one‐step ultrasound treatment at a low pH. The wettability of the SHphi‐MFS is completely switched from the outside to the inside of the MFS. After wettability switching is achieved, the SHpho‐MFS that is prewetted with water and oil is able to selectively separate both water and oil, respectively. A compressed SHpho‐MFS also exhibits excellent separation performance of a water‐in‐oil emulsion. Furthermore, since the SHpho‐MFS can linearly release protons in an aqueous solution, during the oil/water separation (water‐removing), an aqueous solution of a strong base is neutralized or changed into a certain solution with a tailored pH by a simple filtration step using an appropriately sized SHpho‐MFS. The SHpho‐MFS can maintain a slow reaction rate and reduce the sudden release of heat during neutralization. Controlled release of the SHpho‐MFS capable of the ordered production of protons on demand is also achieved because the release “on and off” behavior of protons is repeatedly observed for every cycle.
Synthesis of Polycyclic Quinolines by Means of Brønsted Acid Mediated Reaction of β‐(2‐Aminophenyl)‐α,β‐Ynones with Ketones
Authors: Marsicano Vincenzo , Chiarini Marco , Marinelli Fabio , Arcadi Antonio
Published: March 2019

Sequential Brønsted acid promoted amination/annulation/aromatization of β‐(2‐aminophenyl)‐α,β‐ynones with cyclic α‐methylene carbonyl compounds has been developed for the synthesis of polycyclic quinolines in good to high yields in ethanol. The protocol achieves the selective formation of the target quinolines and is expected to find practical applications due to its operational simplicity.

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Reactive Oxygen Species‐Responsive Nanoparticles for the Treatment of Ischemic Stroke
Authors: Rajkovic Olivera , Gourmel Charlotte , d'Arcy Richard , Wong Raymond , Rajkovic Ivana , Tirelli Nicola , Pinteaux Emmanuel
Published: March 2019

Ischemic stroke is a leading cause of death and long‐term disability worldwide, yet availability of current treatments is limited. The downstream events resulting from cerebral ischemia lead to an imbalance in the production of harmful reactive oxygen species (ROS) over endogenous antioxidant mechanisms. Thus, treatments that can reduce this imbalance can limit the extent of injury resulting from ischemic stroke. In this work, the potential of novel ROS‐scavenging PEGylated polymeric nanoparticles (NPs) composed of poly(propylene sulfide) (PPS) (PPS‐NPs) for ischemic stroke therapy is evaluated in vitro and in a mouse model of stroke. In vitro results show that PPS‐NPs display remarkable anti‐oxidant and anti‐inflammatory properties, whilst exhibiting negligible cytotoxicity. NPs administered intravenously rapidly accumulate in ischemic brain regions as visualized through fluorescence imaging, reduced infarct volume, blood‐brain barrier damage, neuronal loss, and neuroinflammation as determined by immunohistochemistry, and improved recovery of neurological function as determined through behavioral analyses. Crucially, the data show that the therapeutic time window for administration of PPS‐NPs extends up to 3 h, a clinically relevant time window for stroke. The findings provide new strong evidence that these NPs may be an effective antioxidant therapy for ischemic stroke.
A Stable Layered Oxide Cathode Material for High‐Performance Sodium‐Ion Battery
Authors: Xiao Yao , Zhu Yan‐Fang , Yao Hu‐Rong , Wang Peng‐Fei , Zhang Xu‐Dong , Li Hongliang , Yang Xinan , Gu Lin , Li Yong‐Chun , Wang Tao , Yin Ya‐Xia , Guo Xiao‐Dong , Zhong Ben‐He , Guo Yu‐Guo
Published: March 2019

As one of the most promising cathode candidates for room‐temperature sodium‐ion batteries (SIBs), P2‐type layered oxides face the challenge of simultaneously realizing high‐rate performance while achieving long cycle life. Here, a stable Na2/3Ni1/6Mn2/3Cu1/9Mg1/18O2 cathode material is proposed that consists of multiple‐layer oriented stacking nanoflakes, in which the nickel sites are partially substituted by copper and magnesium, a characteristic of the material that is confirmed by multiscale scanning transmission electron microscopy and electron energy loss spectroscopy techniques. Owing to the optimal morphology structure modulation and chemical element substitution strategy, the electrode displays remarkable rate performance (73% capacity retention at 30C compared to 0.5C) and outstanding cycling stability in Na half‐cell system couple with unprecedented full battery performance. The underlying thermal stability, phase stability, and Na+ storage mechanisms are clearly elucidated through the systematical characterizations of electrochemical behaviors, in situ X‐ray diffraction at different temperatures, and operando X‐ray diffraction upon Na+ deintercalation/intercalation. Surprisingly, a quasi‐solid‐solution reaction is switched to an absolute solid‐solution reaction and a capacitive Na+ storage mechanism is demonstrated via quantitative electrochemical kinetics calculation during charge/discharge process. Such a simple and effective strategy might reveal a new avenue into the rational design of excellent rate capability and long cycle stability cathode materials for practical SIBs.
Curvature dependence of Henry's law constant and nonideality of gas equilibrium for curved vapor–liquid interfaces
Authors: Wang Xian , Guo Zhenjiang , Liu Zhiping , Zhang Xianren
Published: March 2019

Curved interfaces between coexisting vapor and liquid phases are ubiquitous in nature, and the question of whether the Henry's law is applicable for highly curved vapor/liquid interfaces remains unsolved. Using stable surface nanobubbles that have highly curved interfaces as examples, we investigate the viability of Henry's law with molecular simulations and thermodynamic analysis. We show that the prediction of Henry's law displays an increasingly deviation from the simulation results as nanobubble curvature increases. Such a curvature dependence of Henry's law constant is ascribed to the nonideality of gas in liquid phase because of the required gas supersaturation for stabilizing nanobubbles. Based on the effect, we develop a relationship for determining Henry's law constant from the level of gas supersaturation, as well as a robust relationship between gas supersaturation and nanobubble radius.
Analysis of equilibrium CO2 solubility and thermodynamic models for aqueous 1‐(2‐hydoxyethyl)‐piperidine solution
Authors: Xiao Min , Zheng Wenchao , Liu Helei , Tontiwachwuthikul Paitoon , Liang Zhiwu
Published: March 2019

1‐(2‐Hydoxyethyl)‐piperidine (1‐(2HE)‐PP) is a new tertiary amine with desirable properties and can be potentially used to formulate superior absorbents for CO2 capture. The equilibrium CO2 solubility of 1‐(2HE)‐PP solution is measured over temperatures from 298 to 333 K, CO2 partial pressures from 8.1 to 101.3 kPa and initial amine concentrations from 1 to 5 M. Two thermodynamic models, namely semiempirical model and activity coefficient model are developed for the system. The activity coefficient model shows better estimation solubility with an absolute average relative deviation (AARD) of 7.6%. In the comparison between the two models, a comprehensive analysis is presented. Some suggestions are provided for the similar model development. In addition, the speciation plot of CO2 loaded 1‐(2HE)‐PP solution is predicted based on the activity coefficient model. The predictive pH values agree well with experimental data with AARD of 1.0%. Finally, the potential of 1‐(2‐HE)PP to be an alternative amine in CO2 capture is evaluated.
Role of ionic liquids in the efficient transfer of lithium by Cyanex 923 in solvent extraction system
Authors: Cui Li , Jiang Kun , Wang Junfeng , Dong Kun , Zhang Xiangping , Cheng Fangqin
Published: March 2019

The solvent extraction of Li+ by Cyanex 923 was investigated upon the addition of different imidazolium‐based ionic liquids (ILs). The results showed 1‐hydroxylethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([HOEmim][NTf2]) can improve the extraction of Li+ most effectively. The fundamental mechanism is that [HOEmim][NTf2] can remarkably enhance the coordination ability of Cyanex 923 to Li+ to form more stable and hydrophobic ion‐pair species [Li(Cyanex 923)n][NTf2] (nmax = 3) resulting from the electrostatic interaction and typical hydrogen bonding of IL, and thus facilitating the transfer of Li+ into organic phase. This work has revealed the transfer mechanism of Li+ in a solvent extraction system comprising of IL and neural ligand. The knowledge of the coordination environment of Li+ in the presence of IL also gives us a new insight into the separation of 6Li/7Li. The disadvantage of this process is the loss of IL. However, this study provides guidance for the design of better IL‐based systems for the separation of metal ions.
Fetal cardiomyopathy in neurofibromatosis type I: Novel phenotype and review of the literature
Authors: Ritter Alyssa , Cuddapah Sanmati , Degenhardt Karl , Kasperski Stefanie , Johnson Mark P. , O'Connor Matthew J. , Ahrens‐Nicklas Rebecca
Published: March 2019

Neurofibromatosis type I (NF1) is a relatively common genetic disorder characterized by neurocutaneous lesions, neurofibromas, skeletal anomalies, iris hamartomas, and predisposition to other tumors. NF1 results from heterozygous loss‐of‐function mutations in neurofibromin (NF1), and diagnosis is most often made using clinical diagnostic criteria. Cardiac manifestations of NF1 include congenital heart disease (such as valvar pulmonary stenosis), left ventricular hypertrophy, and adult‐onset pulmonary hypertension. Prenatal features of NF1 are often nonspecific and diagnoses are infrequently made prenatally without a known family history. Herein, we report the first case, to the best of our knowledge, of fetal cardiomyopathy as the presenting feature in NF1 and review NF1‐related left ventricular hypertrophy. NF1 should be considered in the differential diagnosis for fetuses with cardiomyopathy, even in the absence of a known family history of the condition.
Incidental findings on whole‐body computed tomography in trauma patients: the current state of incidental findings and the effect of implementation of a feedback system
Authors: Kumada Keisuke , Murakami Nobuo , Okada Hideshi , Toyoda Izumi , Ogura Shinji , Asano Takahiko
Published: March 2019

Aim

Whole‐body computed tomography (CT) for trauma occasionally reveals significant incidental findings not related to trauma, which require an adequate response. In this study, we examined the current state of incidental findings in trauma patients on whole‐body CT and the effects of the feedback system.

Methods

The subject sample included trauma patients who underwent whole‐body CT while being examined for trauma during the 2‐year period, with the interpretation of the CT reported by a radiologist. The frequency and recognition of incidental findings and the involved body region were investigated. The state of incidental findings before and after implementation of a radiography report feedback system was also examined.

Results

During the study period, whole‐body CT revealed incidental findings in 79 of 199 trauma patients (40.1%). The mean age of the 79 patients with incidental findings was 62.8 ± 19.5 years, and the mean injury severity score was 16.6 ± 10.0. No difference was observed in the severity of trauma, age, or length of hospital stay. The incidental findings were related to the liver/gallbladder in 22 patients, kidneys in 17, lungs in 14, and the intracranial area in 13. The recognition rate of incidental findings after the implementation of the feedback system increased from 23.3% to 32.6%.

Conclusions

Considering that not all incidental findings are accurately recognized, a proper feedback system is required. A feedback system is beneficial and a need to ensure improvement in the recognition of incidental findings.