Flexible and Freestanding MoS2/Graphene Composite for High-Performance Supercapacitors.

Two-dimensional atomically thick materials such as graphene and layered molybdenum disulfide (MoS2) have been studied as potential energy storage materials because of their high specific surface area, potential redox activity, and mechanical flexibility. However, because of the layered structure restacking and poor electrical conductivity, these materials are unable to attain their full potential. Composite electrodes made of a mixture of graphene and MoS2 have been shown to partially resolve these issues in the past, although their performance is still limited by inadequate mixing at the nanoscale. Herein, we report three composites via a simple ball-milling method and analyze supercapacitor electrodes. Compared with pristine graphene and MoS2, the composites showed high capacitance. The as-obtained MoS2@Graphene composite (1:9) possesses a high surface area and uniform dispersion of MoS2 on the graphene sheet. The MoS2@Graphene (1:9) composite electrode has a high specific capacitance of 248 F g-1 at 5 A g-1 in an electrochemical supercapacitor compared with the other two composites. Simultaneously, the flexible symmetric supercapacitor device prepared demonstrated superior flexibility and a long lifespan (93% capacitance retention after 8000 cycles) with no obvious changes in performance under different angles. In portable and wearable energy storage devices, the current experimental results will result in scalable, freestanding hybrid electrodes with improved, flexible, supercapacitive performance.

Robot Navigation Based on Potential Field and Gradient Obtained by Bilinear Interpolation and a Grid-Based Search.

The original concept of the artificial potential field in robot path planning has spawned a variety of extensions to address its main weakness, namely the formation of local minima in which the robot may be trapped. In this paper, a smooth navigation function combining the Dijkstra-based discrete static potential field evaluation with bilinear interpolation is proposed. The necessary modifications of the bilinear interpolation method are developed to make it applicable to the path-planning application. The effect is that the strategy makes it possible to solve the problem of the local minima, to generate smooth paths with moderate computational complexity, and at the same time, to largely preserve the product of the computationally intensive static plan. To cope with detected changes in the environment, a simple planning strategy is applied, bypassing the static plan with the solution of the A* algorithm to cope with dynamic discoveries. Results from several test environments are presented to illustrate the advantages of the developed navigation model.

Insight into thermo-mechanical enhancement of polymer nanocomposites coated microsand proppants for hydraulic fracturing.

The present work reports the fabrication of ultra-high strength microsand proppants (100 mesh) through a polymer nanocomposite dual coating approach and gives insight into their thermo-mechanical reinforcements. The dual coating can be of 3D-cross-linked poly(styrene-methyl methacrylate)/divinylbenzene) (PS-PMMA/DVB) porous network and thermally cross-linked epoxy with graphene nanosheets. The inner layer of PS-PMMA/DVB was prepared using bulk polymerization of styrene (S) and methyl methacrylate (MMA) at 70 °C with a free radical initiator azobisisobutyronitrile (AIBN). The outer layer was prepared by mixing epoxy resin, a cross-linker, and commercial graphene (CG) followed by thermally curing the mixture. The dual-coated microsand proppants exhibited enhanced mechanical characteristics of elastic modulus (E) as high as 7.78 GPa, hardness (H) of 0.35 GPa, and fracture toughness (Kc) of 3.19 MPa m1/2 along with largely improved thermal properties. Moreover, the dual-coated microsand proppants exhibit a very high-stress resistance up to 14000 psi, and to the best of our knowledge, this is the highest stress resistance value attained for the modified sand-based proppants so far.

Microwave Irradiation Synthesis and Characterization of Reduced-(Graphene Oxide-(Polystyrene-Polymethyl Methacrylate))/Silver Nanoparticle Nanocomposites and their Anti-Microbial Activity.

Herein, we report a facile process for the preparation of styrene and methyl-methacrylate copolymer nanocomposites containing reduced graphene oxide and silver nanoparticles ((R-(GO-(PS-PMMA))/AgNPs)) by using (i) microwave irradiation (MWI) to obtain R-(GO-(PS-PMMA))/AgNPs and (ii) the in situ bulk polymerization technique to produce RGO/AgNPs-(PS-PMMA). Various characterization techniques, including FT-IR, XPS, Raman spectroscopy, XRD, SEM, HR-TEM, DSC, and TGA analysis, were used to characterize the prepared nanocomposites. The Berkovich nanoindentation method was employed to determine the hardness and elastic modulus of the nanocomposites. The results showed that the MWI-produced nanocomposites were found to have enhanced morphological, structural, and thermal properties compared with those of the nanocomposites prepared by the in situ method. In addition, the antibacterial activity of the prepared nanocomposites against the E. coli HB 101 K-12 was investigated, whereby an inhibition zone of 3 mm (RGO/AgNPs-(PS-PMMA) and 27 mm (R-(GO-(PS-PMMA))/AgNPs) was achieved. This indicates that the MWI-prepared nanocomposite has stronger antibacterial activity than the in situ-prepared nanocomposite.

Li-Ion Capacitor Integrated with Nano-network-Structured Ni/NiO/C Anode and Nitrogen-Doped Carbonized Metal-Organic Framework Cathode with High Power and Long Cyclability.

Lithium-ion capacitors (LICs) represent a new type of energy-storage devices, which have combined merits of high energy density Li-ion battery and high power density supercapacitor. Nevertheless, one significant challenge for LICs is the imbalanced kinetics between the fast capacitive cathode and relatively slow intercalation anode that limit the energy-storage performance. Here, the asymmetric LIC devices were developed based on a nitrogen-doped, carbonized zeolitic imidazolate framework (ZIF-8) cathode and a three-dimensional, nano-network-structured, conversion reaction-based Ni/NiO/C anode. These nanostructures associated with both the cathode and anode enable rapid electron and ions transport in the LIC devices, which allows the asymmetric LICs to be operated on either high energy mode (energy density of 114.7 Wh/kg at power density of 98.0 W/kg) or high power mode (power density of 60.1 kW/kg at energy density of 17.6 Wh/kg). The device also exhibited long-term cycle stability with 87% capacitance retention after 12 000 cycles. These results demonstrate that the rational design of nanoporous electrode structures can deliver a balanced, high-performance-activated cZIF-8|Ni/NiO/C-based lithium-ion capacitor.

Directed Self-Assembly of Star-Block Copolymers by Topographic Nanopatterns through Nucleation and Growth Mechanism.

Exploring the ordering mechanism and dynamics of self-assembled block copolymer (BCP) thin films under confined conditions are highly essential in the application of BCP lithography. In this study, it is aimed to examine the self-assembling mechanism and kinetics of silicon-containing 3-arm star-block copolymer composed of polystyrene (PS) and poly(dimethylsiloxane) blocks as nanostructured thin films with perpendicular cylinders and controlled lateral ordering by directed self-assembly using topographically patterned substrates. The ordering process of the star-block copolymer within fabricated topographic patterns with PS-functionalized sidewall can be carried out through the type of secondary (i.e., heterogeneous) nucleation for microphase separation initiated from the edge and/or corner of the topographic patterns, and directed to grow as well-ordered hexagonally packed perpendicular cylinders. The growth rate for the confined microphase separation is highly dependent upon the dimension and also the geometric texture of the preformed pattern. Fast self-assembly for ordering of BCP thin film can be achieved by lowering the confinement dimension and also increasing the concern number of the preformed pattern, providing a new strategy for the design of BCP lithography from the integration of top-down and bottom-up approaches.

Fabrication of Mesoporous Polystyrene Films with Controlled Porosity and Pore Size by Solvent Annealing for Templated Syntheses.

Herein, we aim to develop a facile method for the fabrication of mesoporous polystyrene (PS) films with controlled porosity and pore size by solvent annealing. A PS polymer film is solvent-annealed using N,N-dimethyl formamide (DMF) vapor for the development of phase separation, followed by rapidly cooling to the preset cryogenic temperature. Subsequently, a nonsolvent (methanol) is introduced to extract the crystalline DMF from the DMF-swollen PS, giving mesoporous PS with a network structure after the removal of DMF. The porosity of the mesoporous PS films can be controlled by the degree of swelling. Most interestingly, the phase separation between PS and DMF at the thin-film state under solvent annealing can be regulated by the annealing time through the spinodal decomposition, giving the development of nanonetwork structure with controlled structural features (i.e., framework size and interframework spacing) at invariant porosity. Consequently, after the removal of DMF, mesoporous PS films with controlled porosity and pore size can be obtained and then used as a template for the fabrication of a variety of nanoporous inorganics by templated syntheses, such as nanoporous SiO2, TiO2, and Ni, providing a cost-effective way to fabricate a range of nanoporous materials with controlled porosity and pore size as well as large specific surface area for aimed applications.

Hydrophilic polymer nanofibre networks for rapid removal of aromatic compounds from water.

Hydrophobic mesoporous polymer nanofibre networks were converted to hydrophilic ones by a mild sulfonation reaction. The resultant mesoporous polystyrene with a large free surface area effectively captured water-soluble dye molecules and allowed aromatic compounds to rapidly permeate into the internal binding sites.

Flash freezing route to mesoporous polymer nanofibre networks.

There are increasing requirements worldwide for advanced separation materials with applications in environmental protection processes. Various mesoporous polymeric materials have been developed and they are considered as potential candidates. It is still challenging, however, to develop economically viable and durable separation materials from low-cost, mass-produced materials. Here we report the fabrication of a nanofibrous network structure from common polymers, based on a microphase separation technique from frozen polymer solutions. The resulting polymer nanofibre networks exhibit large free surface areas, exceeding 300 m(2) g(-1), as well as small pore radii as low as 1.9 nm. These mesoporous polymer materials are able to rapidly adsorb and desorb a large amount of carbon dioxide and are also capable of condensing organic vapours. Furthermore, the nanofibres made of engineering plastics with high glass transition temperatures over 200 °C exhibit surprisingly high, temperature-dependent adsorption of organic solvents from aqueous solution.

Hemosuccus pancreaticus: a rare cause of gastrointestinal bleeding.

Hemorrhage from the pancreatic duct, referred to as hemosuccus pancreaticus or pseudohemobilia, is a rare cause of gastrointestinal (GI) bleeding. This potentially life-threatening complication of pancreatitis may pose a significant diagnostic and therapeutic dilemma, especially in patients who do not exhibit symptoms such as abdominal pain, jaundice, or GI bleeding. Here we describe a 55-year-old male with a known history of chronic calcifying pancreatitis, who presented with repeated episodes of melena associated with paroxysms of abdominal pain and frequent drop in hemoglobin requiring hospitalization. Initial endoscopic evaluation was negative. Endoscopy was repeated after an episode of melena which showed blood spurting from the ampulla. Further evaluation with abdominal CT scan, CT angiogram and conventional angiogram revealed no source of blood loss. Hence emergency surgery was done. There was evidence of splenic vein rupturing into the pancreatic duct.

Use of the Tower of London - Drexel University, Second Edition (TOLDX) in adults with traumatic brain injury.

The Tower of London - Drexel University, Second Edition (TOL(DX)) was investigated in order to determine the efficacy of using this instrument in evaluating the impact of traumatic brain injury on cognitive functioning in adults. Performance on the TOL(DX) was compared among 56 individuals with complicated mild to severe traumatic brain injury ("sTBI"), 68 individuals with uncomplicated, mild traumatic brain injury ("mTBI"), and 124 demographically matched, healthy controls. Both TBI groups performed worse than controls on TOL(DX) measures of executive time (ET) and number of moves used (TMS), but only patients with sTBI were more likely to be impaired on TMS (i.e., performing at least 1.5 SD below the mean). Poorer performance on TMS was associated with increasing length of coma. Although poor sensitivity of this measure limits its use in isolation, the TOL(DX) may provide a complementary measurement of aspects of problem-solving deficit in TBI that may not be captured by other tests.

Absence of gastrointestinal pathogens in ileum tissue resected for necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is one of the most common gastrointestinal emergencies in premature infants and has been linked with viral antigens in as much as 40% of cases in single-center cohorts. We examined 28 tissue sections from surgically resected ileum from 27 preterm infants with NEC from 2 separate institutions for 15 common bacterial, viral, and parasitic gastrointestinal pathogens using multiplex reverse transcriptase polymerase chain reaction amplification and suspension array detection methods. We did not detect infectious enteritis pathogens in any of the NEC tissues and conclude that gastrointestinal pathogens are a rare cause of NEC.

Embedded assessment of validity using the continuous visual memory test in patients with traumatic brain injury.

Retrospective review of a consecutive patient series (n = 115) referred for neuropsychological examinations for traumatic brain injury was undertaken to evaluate an embedded measure of symptom validity for the Continuous Visual Memory Test (CVMT). Performance on the Test of Memory Malingering (TOMM) and Word Memory Test (WMT) was used for classification. Individuals who failed the TOMM or WMT were almost six times more likely to fail the CVMT validity criteria than those who passed the TOMM or WMT. The addition of compensation seeking increased this odds ratio to 9.80. The area under the curve for the latter classification was 0.74. Maximum likelihood ratio optimization of the CVMT validity test cutoff score indicated sensitivity of 0.25 and specificity of 0.99 at a revised cutoff of <12 items. Classification accuracy was 91%. The original cutoff score of <14 items also performed acceptably, with a classification accuracy of 88%. While low sensitivity argues against use in isolation, the proposed measure has utility in conjunction with other established effort measures.

Factor-analytic study of the Yale Global Tic Severity Scale.

We report on the factor structure of the Yale Global Tic Severity Scale. Participants were 76 children and adolescents diagnosed with tic disorders. Overall, the model proposed by Leckman et al. [Leckman, J.F., Riddle, M.A., Hardin, M.T., Ort, S.I., Swartz, K.L., Stevenson, J., Cohen, D.J., 1989. The Yale Global Tic Severity Scale: initial testing of a clinician-rated scale of tic severity. Journal of the American Academy of Child and Adolescent Psychiatry 28, 566-573.] represented an adequate fit. The internal consistency of the factors was acceptable and the convergent and divergent validity was supported vis-à-vis correlations with parent ratings of Tourette's Disorder symptoms. These findings support the use of the original scoring structure in assessing pediatric tic severity.

The psychometric properties of the Brief Fear of Negative Evaluation Scale.

This study examined the psychometric properties of the Brief Fear of Negative Evaluation (BFNE) Scale in a nonclinical, nonstudent sample. Participants were administered the BFNE Scale, Beck Depression Inventory (BDI), and the UCLA Loneliness Scale. No differences were found across age, but women scored significantly higher on the BFNE Scale than men. Confirmatory factor analysis supported a two-factor solution corresponding to positive and reverse scored items. Internal consistency was excellent for the positive scored factor (alpha=.94), acceptable for the reverse scored factor (alpha=.73), and good for the full BFNE Scale (alpha=.80). BFNE scores were significantly correlated in the expected directions with the BDI and the UCLA Loneliness Scale. Implications of these findings for clinical practice and future research are discussed.

The effects of preexisting depression on cerebrovascular health outcomes in geriatric continuing care.

BACKGROUND: Previous studies have investigated depression as the cause and outcome of vascular deficit in elderly persons. METHODS: The authors wanted to determine whether baseline depression is predictive of subsequent cardiovascular events in very elderly persons residing in a continuing care retirement community (n = 181). RESULTS: Controlling for demographic factors, both depression and the number of cardiovascular risk factors (CVRFs) at baseline were strongly predictive of stroke, whereas only CVRFs strongly predicted myocardial infarctions. Depression accounted for 12% of the variance in stroke incidence, beyond the contribution of CVRFs. Path analysis indicated that depression was also a partial moderator of the effect of CVRFs. CONCLUSIONS: In support of the vascular depression hypothesis, the study findings indicate that, for the oldest old, depression may be a strong predictor of future stroke. The presence of depression in elderly patients should alert physicians to carefully investigate other stroke risk factors and to integrate depression into an overall intervention regimen for reducing patients' risks for stroke.

Improved extraction of ePTFE and medical adhesive modified defibrillation leads from the coronary sinus and great cardiac vein.

BACKGROUND: Permanent leads with shocking coils for defibrillation therapy are sometimes implanted in the coronary sinus (CS) and great cardiac vein (GCV). These shocking coils, as documented by pathologic examination of animal investigations, often become tightly encapsulated by fibrosis and can be very difficult to remove. METHODS: One of three configurations of the Guidant model 7109 Perimeter coronary sinus shocking lead was implanted into the distal portion of the GCV of 24 sheep for up to 14 months. Group 1 had unmodified coils (control), group 2 had coils backfilled with medical adhesive (MA), and Group 3 had coils coated with expanded polytetrafluoroethylene (ePTFE). Eighteen leads, three from each group at 6 and 14 months were transvenously extracted from the left jugular vein. The remaining six animals were not subject to extraction. All animals were euthanized for pathological and microscopic examination. RESULTS: All six of the control, three of the MA, and one of the ePTFE leads required the use of an electrosurgical dissection sheath (EDS) for extraction. Five control, two MA, and none of the ePTFE leads had significant fibrotic attachments to the shocking coils. Significant trauma was observed at necropsy for those leads requiring the use of the EDS for extraction. CONCLUSIONS: Tissue ingrowth is a major impediment to the removal of defibrillation leads implanted in the CS and GCV of sheep. Reduction of tissue ingrowth by coating the shocking coils with ePTFE or by backfilling with MA facilitates transvenous lead removal with reduced tissue trauma.

Disaster management actions plans for the state of Maharashtra : A review of its unique components

The foremost and the first disaster management plan has been one of the greatest achievements in India during IDNDR. The focus of the plan is mainly on preparedness and mitigation with a clearly identified state and district action plans inclusive of technological risk mitigation plan wich has included the management of disasters envisage from hazarduous industries. Maharashtra has therefore set up an example for other states to follow. (AU)