Synergistic effect of a defect-free graphene nanostructure as an anode material for lithium ion batteries

© 2019 by the authors. Licensee MDPI, Basel, Switzerland.Graphene nanosheets have been among the most promising candidates for a highperformance anode material to replace graphite in lithium ion batteries (LIBs). Studies in this area have mainly focused on nanostructured electrodes synthesized by graphene oxide (GO) or reduced graphene oxide (rGO) and surface modifications by a chemical treatment. Herein, we propose a cost-effective and reliable route for generating a defect-free, nanoporous graphene nanostructure (df-GNS) through the sequential insertion of pyridine into a potassium graphite intercalation compound (K-GIC). The as-prepared df-GNS preserves the intrinsic property of graphene without any crystal damage, leading to micro-/nano-porosity (microporosity: ~10–50 µm, nanoporosity: ~2– 20 nm) with a significantly large specific surface area. The electrochemical performance of the dfGNS as an anode electrode was assessed and showed a notably enhanced capacity, rate capability, and cycle stability, without fading in capacity or decaying. This is because of the optimal porosity, with perfect preservation of the graphene crystal, allowing faster ion access and a high amount of electron pathways onto the electrode. Therefore, our work will be very helpful for the development of anode and cathode electrodes with higher energy and power performance requirement

Nearly Perfect Durable Superhydrophobic Surfaces Fabricated by a Simple One-Step Plasma Treatment

Fabrication of superhydrophobic surfaces is an area of great interest because it can be applicable to various engineering fields. A simple, safe and inexpensive fabrication process is required to fabricate applicable superhydrophobic surfaces. In this study, we developed a facile fabrication method of nearly perfect superhydrophobic surfaces through plasma treatment with argon and oxygen gases. A polytetrafluoroethylene (PTFE) sheet was selected as a substrate material. We optimized the fabrication parameters to produce superhydrophobic surfaces of superior performance using the Taguchi method. The contact angle of the pristine PTFE surface is approximately 111.0�� �� 2.4��, with a sliding angle of 12.3�� �� 6.4��. After the plasma treatment, nano-sized spherical tips, which looked like crown-structures, were created. This PTFE sheet exhibits the maximum contact angle of 178.9��, with a sliding angle less than 1��. As a result, this superhydrophobic surface requires a small external force to detach water droplets dripped on the surface. The contact angle of the fabricated superhydrophobic surface is almost retained, even after performing an air-aging test for 80 days and a droplet impacting test for 6 h. This fabrication method can provide superb superhydrophobic surface using simple one-step plasma etching. ? 2017 The Author(s).114Ysciescopu

Modelling of Tirapazamine effects on solid tumour morphology

Bioreductive drugs are in clinical practice to exploit the resistance from tumour microenvironments especially in the hypoxic region of tumour. We pre-sented a tumour treatment model to capture the pharmacology of one of the most prominent bioreductive drugs, Tirapazamine (TPZ) which is in clinical trials I and II. We calculated solid tumour mass in our previous work and then integrated that model with TPZ infusion. We calculated TPZ cytotoxicity, concentration, penetra-tion with increasing distance from blood vessel and offered resistance from micro-environments for drug penetration inside the tumour while considering each cell as an individual entity. The impact of these factors on tumour morphology is also showed to see the drug behaviour inside animals/humans tumours. We maintained the heterogeneity factors in presented model as observed in real tumour mass es-pecially in terms of cells proliferation, cell movement, extracellular matrix (ECM) interaction, and the gradients of partial oxygen pressure (pO2) inside tumour cells during the whole growth and treatment activity. The results suggest that TPZ high concentration in combination with chemotherapy should be given to get maximum abnormal cell killing. This model can be a good choice for oncologists and re-searchers to explore more about TPZ action inside solid tumour

Mapping aerial metal deposition in metropolitan areas from tree bark : a case study in Sheffield, England

We investigated the use of metals accumulated on tree bark for mapping their deposition across metropolitan Sheffield by sampling 642 trees of three common species. Mean concentrations of metals were generally an order of magnitude greater than in samples from a remote uncontaminated site. We found trivially small differences among tree species with respect to metal concentrations on bark, and in subsequent statistical analyses did not discriminate between them. We mapped the concentrations of As, Cd and Ni by lognormal universal kriging using parameters estimated by residual maximum likelihood ({\sc reml}). The concentrations of Ni and Cd were greatest close to a large steel works, their probable source, and declined markedly within 500~metres of it and from there more gradually over several kilometres. Arsenic was much more evenly distributed, probably as a result of locally mined coal burned in domestic fires for many years. Tree bark seems to integrate airborne pollution over time, and our findings show that sampling and analysing it are cost-effective means of mapping and identifying sources

A randomised, double-blind, phase 3 study comparing the efficacy and safety of ceftazidime/avibactam plus metronidazole versus meropenem for complicated intra-abdominal infections in hospitalised adults in Asia

Ceftazidime/avibactam comprises the broad-spectrum cephalosporin ceftazidime and the non-β-lactam β-lactamase inhibitor avibactam. This phase 3, randomised, double-blind study (NCT01726023) assessed the efficacy and safety of ceftazidime/avibactam plus metronidazole compared with meropenem in patients with complicated intra-abdominal infection (cIAI) in Asian countries. Subjects aged 18–90 years and hospitalised with cIAI requiring surgical intervention were randomised 1:1 to receive every 8 h either: ceftazidime/avibactam (2000/500 mg, 2-h infusion) followed by metronidazole (500 mg, 60-min infusion); or meropenem (1000 mg, 30-min infusion). Non-inferiority of ceftazidime/avibactam plus metronidazole to meropenem was concluded if the lower limit of the 95% confidence interval (CI) for the between-group difference in clinical cure rate was greater than −12.5% at the test-of-cure (TOC) visit (28–35 days after randomisation) in the clinically evaluable (CE) population. Safety was also evaluated. Of 441 subjects randomised, 432 received at least one dose of study medication (ceftazidime/avibactam plus metronidazole, n = 215; meropenem, n = 217). In the CE population at the TOC visit, non-inferiority of ceftazidime/avibactam plus metronidazole to meropenem was demonstrated, with clinical cure reported for 93.8% (166/177) and 94.0% (173/184) of subjects, respectively (between-group difference, −0.2, 95% CI −5.53 to 4.97). The clinical cure rate with ceftazidime/avibactam plus metronidazole was comparable in subjects with ceftazidime-non-susceptible and ceftazidime-susceptible isolates (95.7% vs. 92.1%, respectively). Adverse events were similar between the study groups. Ceftazidime/avibactam plus metronidazole was non-inferior to meropenem in the treatment of cIAIs in Asian populations and was effective against ceftazidime-non-susceptible pathogens. No new safety concerns were identified

Disruption of the leptomeningeal blood barrier in neuromyelitis optica spectrum disorder

OBJECTIVE: To describe leptomeningeal blood-barrier impairment reflected by MRI gadolinium-enhanced lesions in patients with aquaporin-4 immunoglobulin G (AQP4-IgG)-positive neuromyelitis optica spectrum disorder (NMOSD). METHODS: A retrospective case series of 11 AQP4-IgG-positive NMOSD patients with leptomeningeal enhancement (LME) were collected from 5 centers. External neuroradiologists, blinded to the clinical details, evaluated MRIs. RESULTS: LME was demonstrated on postcontrast T1-weighted and fluid-attenuated inversion recovery images as a sign of leptomeningeal blood-barrier disruption and transient leakage of contrast agent into the subarachnoid space in 11 patients, 6 in the brain and 6 in the spinal cord. The patterns of LME were linear or extensive and were accompanied by periependymal enhancement in 5 cases and intraparenchymal enhancement in all cases. The location of LME in the spinal cord was adjacent to intraparenchymal contrast enhancement with involvement of a median number of 12 (range 5-17) vertebral segments. At the time of LME on MRI, all patients had a clinical attack such as encephalopathy (36%) and/or myelopathy (70%) with median interval between symptom onset and LME of 12 days (range 2-30). LME occurred in association with an initial area postrema attack (44%), signs of systemic infection (33%), or AQP4-IgG in CSF (22%) followed by clinical progression. LME was found at initial clinical presentation in 5 cases and at clinical relapses leading to a diagnosis of NMOSD in 6 cases. CONCLUSION: This study suggests that altered leptomeningeal blood barrier may be accompanied by intraparenchymal blood-brain barrier breakdown in patients with AQP4-IgG-positive NMOSD during relapses

Linear Contraction Behavior of Low-Carbon, Low-Alloy Steels During and After Solidification Using Real-Time Measurements

A technique for measuring the linear contraction during and after solidification of low-alloy steel was developed and used for examination of two commercial low-carbon and low-alloy steel grades. The effects of several experimental parameters on the contraction were studied. The solidification contraction behavior was described using the concept of rigidity in a solidifying alloy, evolution of the solid fraction, and the microstructure development during solidification. A correlation between the linear contraction properties in the solidification range and the hot crack susceptibility was proposed and used for the estimation of hot cracking susceptibility for two studied alloys and verified with the real casting practice. The technique allows estimation of the contraction coefficient of commercial steels in a wide range of temperatures and could be helpful for computer simulation and process optimization during continuous casting. © 2013 The Minerals, Metals & Materials Society and ASM International

Alpha scattering and capture reactions in the A = 7 system at low energies

Differential cross sections for $^3$He-$\alpha$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for $^3$He $+ \alpha$ and $^3$H $+ \alpha$ scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S-factors of the capture reactions $^3$He$(\alpha,\gamma)^7$Be and $^3$H$(\alpha,\gamma)^7$Li, and the branching ratios for the transitions into the two final $^7$Be and $^7$Li bound states, respectively. For $^3$He$(\alpha,\gamma)^7$Be excellent agreement between calculated and experimental data is obtained. For $^3$H$(\alpha,\gamma)^7$Li a $S(0)$ value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of $R = \sigma(\gamma_1)/\sigma(\gamma_0) \approx 0.43$ has been obtained.Comment: submitted to Phys.Rev.C, 34 pages, figures available from one of the authors, LaTeX with RevTeX, IK-TUW-Preprint 930540

Theoretical study of the influence of the morphology in polymer-based devices functioning

It is well known that the morphology of polymer-based optoelectronic devices can influence their efficiency, since the ways that polymer chains pack inside the active layer can influence not only the charge transport but also the optic properties of the device. By using a mesoscopic model we carried out computer experiments to study the influence of the polymer morphology on the processes of charge injection, transport, recombination and collection by the electrodes opposite to those where the injection of bipolar charge carriers take place. Our results show that for polymer layers where the conjugated segments have perpendicular and random orientation relative to the electrodes surface, the competition between charge collection and charge recombination is affected when the average conjugation length of the polymer strands increase. This effect is more pronounced with the increase of the potential barrier at polymer/electrode interfaces that limit charge injection and increase charge collection. For these molecular arrangements the intra-molecular charge transport plays a major role in device performance, being this effect negligible when the polymer molecules have their axis parallel to the electrodes. Although the polymer morphology modelled in this work is far from real, we believe that our model can give some insights on the role of the microstructure on the functioning of polymer-based devices.European Community Fund (FEDER)Fundação para a Ciência e a Tecnologia (FCT) – Programa Operacional “Ciência , Tecnologia, Inovação” – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005 e SFRH/BD/22143/200

Quantitative conditional quantum erasure in two-atom resonance fluorescence

We present a conditional quantum eraser which erases the a priori knowledge or the predictability of the path a photon takes in a Young-type double-slit experiment with two fluorescent four-level atoms. This erasure violates a recently derived erasure relation which must be satisfied for a conventional, unconditional quantum eraser that aims to find an optimal sorting of the system into subensembles with particularly large fringe visibilities. The conditional quantum eraser employs an interaction-free, partial which-way measurement which not only sorts the system into optimal subsystems with large visibility but also selects the appropriate subsystem with the maximum possible visibility. We explain how the erasure relation can be violated under these circumstances.Comment: Revtex4, 12pages, 4 eps figures, replaced with published version, changes in Sec. 3, to appear in Physical Review