Three-dimensional fuzzy graphene ultra-microelectrodes for subcellular electrical recordings

Microelectrode arrays (MEAs) have enabled investigation of cellular networks at sub-millisecond temporal resolution. However, current MEAs are limited by the large electrode footprint since reducing the electrode's geometric area to sub-cellular dimensions leads to a significant increase in impedance thus affecting its recording capabilities. We report a breakthrough ultra-microelectrodes platform by leveraging the outstanding surface-to-volume ratio of nanowire-templated out-of-plane synthesized three-dimensional fuzzy graphene (NT-3DFG). The enormous surface area of NT-3DFG leads to 140-fold reduction in electrode impedance compared to bare Au microelectrodes, thus enabling scaling down the geometric size by 625-fold to ca. 2 μm × 2 μm. The out-of-plane morphology of NT-3DFG leads to a tight seal with the cell membrane thus enabling recording of electrical signals with high signal-to-noise ratio (SNR) of > 6. This work highlights the possibility to push the limits of the conventional MEA technology to enable electrophysiological investigation at sub-cellular level without the need of any surface coatings. This presented approach would greatly impact our basic understanding of signal transduction within a single cell as well as complex cellular assemblies.

     

Comparative analysis of rockmass characterization techniques for the stability prediction of road cut slopes along NH-44A,Mizoram, India

The network of roads in hilly areas plays an important role in the socio-economic development of any country. Instability in road cut slopes is the most critical and common problem in the Northeast region of India. We conducted rockmass characterization of thirteen slopes from three regions, namely Lengpui, Phunchawng and Aizawl Zoo areas near the Aizawl city, on the basis of rock mass rating (RMR), geological strength index (GSI), kinematic analysis, and various slope mass rating techniques. Wedge failure was observed to be prominent in these regions, though some other modes of failure were present at the site. The stability of road cut slopes was found to vary from partially stable to completely unstable with regard to slope mass rating (SMR), Chinese slope mass rating (CSMR) and the continuous slope mass rating (CoSMR). A comparative analysis was also carried out among the findings of various rockmass characterization techniques to predict the stability of the road cut slopes along NH-44A highway.

     

Numerical simulation of adiabatic and isothermal cracks in functionally graded materials using optimized element-free Galerkin method

In the present work, element-free Galerkin method (EFGM) is modified and implemented to simulate thermoelastic fracture in functionally graded materials (FGMs). By solving the simple heat transfer problem, the temperature distribution over the domain can be obtained which is later used as an input to determine the displacement and stress fields. The crack surfaces are modeled under adiabatic and isothermal conditions. To capture stress fields around the crack tip, intrinsic enrichment criterion is used. A modified conservative M-integral technique has been used to extract the stress intensity factors (SIFs) for the simulated problems. A new algorithm to ensure equal number of nodes in support domain has been suggested. The optimum size of support domain is derived by performing an optimization of predefined EFGM parameters, namely, total number of nodes in problem geometry, Gauss quadrature, and number of nodes in support domain. Taguchi L-16 orthogonal array is used to obtain optimized values of these parameters. The results of analysis by optimized EFGM (OEFG) show about 80% reduction in computational time and an improvement in accuracy over EFGM. The present analysis shows that the results obtained by OEFG are in good agreement with those available in the literature.     

Ammoximation of Cyclohexanone over Al2O3 Supported Titanium Silicates

The ammoximation of cyclohexanone to cyclohexanone oxime with H₂O₂ and NH₃, in liquid phase, over γ-Al₂O₃ supported titanium silicates, is reported. The effects of temperature, reactant concentrations and support to catalyst ratio on the efficiency of the process are examined. A maximum yield of 94·48% with selectivity 98·49% for oxime could be achieved over 50 wt% γ-Al₂O₃ supported titanium silicates, at a cyclohexanone: NH₃: H₂O₂ molar ratio of 1:1·5:1, and at a temperature of 313 K. Studies suggest that in the case of a supported catalyst, the catalyst: ketone ratio is about eight times less than that needed for an unsupported catalyst. A batchwise addition of cyclohexanone and ammonia and a dropwise addition of H₂O₂ produced the best results. A tentative mechanism for the production of oxime and by-products is suggested. © 1997 SCI.     

How to Cope with the Challenges of Environmental Stresses in the Era of Global Climate Change: An Update on ROS Stave off in Plants

With the advent of human civilization and anthropogenic activities in the shade of urbanization and global climate change, plants are exposed to a complex set of abiotic stresses. These stresses affect plants’ growth, development, and yield and cause enormous crop losses worldwide. In this alarming scenario of global climate conditions, plants respond to such stresses through a highly balanced and finely tuned interaction between signaling molecules. The abiotic stresses initiate the quick release of reactive oxygen species (ROS) as toxic by-products of altered aerobic metabolism during different stress conditions at the cellular level. ROS includes both free oxygen radicals {superoxide (O₂^•−) and hydroxyl (OH⁻)} as well as non-radicals [hydrogen peroxide (H₂O₂) and singlet oxygen (¹O₂)]. ROS can be generated and scavenged in different cell organelles and cytoplasm depending on the type of stimulus. At high concentrations, ROS cause lipid peroxidation, DNA damage, protein oxidation, and necrosis, but at low to moderate concentrations, they play a crucial role as secondary messengers in intracellular signaling cascades. Because of their concentration-dependent dual role, a huge number of molecules tightly control the level of ROS in cells. The plants have evolved antioxidants and scavenging machinery equipped with different enzymes to maintain the equilibrium between the production and detoxification of ROS generated during stress. In this present article, we have focused on current insights on generation and scavenging of ROS during abiotic stresses. Moreover, the article will act as a knowledge base for new and pivotal studies on ROS generation and scavenging.     

Experimental investigation of IN725 under different cooling environments using new tool holder

Heat buildup is an important issue on the cutting edge which then promotes high-temperature wear which consequently leads to poor machinability during dry machining. To improve the machinability, new tool holder designs accommodating cooling techniques have paid considerable attention toward the manufacturing domain recently. Whereas, in this paper, a new tool holder is designed and fabricated to serve for multipurpose cooling arrangements (internal cooling, external cooling) to reduce the heat buildup of the cutting edge along with the consolidated air system to clear away the chips. Initially, need of new tool holder is discussed followed by its manufacturability and machinability characteristics to a machine for nickel alloy Inconel 725. Machinability studies then are compared for dry machining, internal and external wet machining, and tool wear results are discussed. Thus, improvement in tool wear of around 70–75% and 65–72% is observed for internal wet, external wet concerning dry machining, respectively. Whereas, 15–18% (flank wear) and 6–9% (nose wear) improvement are seen for internal wet machining when compared with external wet machining. Results are best understood for internal cooling using a new tool holder.     

DerainGAN: Single image deraining using wasserstein GAN

Multimedia Tools and Applications - Rainy weather greatly affects the visibility of salient objects and scenes in the captured images and videos. The object/scene visibility varies with the type of...     

A very high performance compact CMOS current mirror

This paper proposes a very high performance current mirror (CM), where output current accurately copies the input current without carrying any offset component. Compact implementation of Garimella et al. CM structure has been combined with super cascode configuration to achieve the proposed very high performance CM. The proposed CM offers extremely high output resistance, very low input resistance and high degree of copying accuracy over a wide operating current range. Small signal analysis is carried out to validate the performance characteristics of the circuit. The proposed CM is simulated by Mentor Graphics Eldospice in TSMC 0.18 µm CMOS, BSIM3 and Level 53 technology, using a single supply voltage of 1.5 V. The circuit is shown to have high current copying accuracy for a range of (0–500 µA) with an error less than 0.0016 % and has no offset current at the output side. The robustness of the proposed CM against the variations in device parameters and temperature changes has been reflected in simulations by carrying Monte Carlo and temperature analysis. The simulation results show that the proposed circuit provides very high output resistance of 55.76 GΩ and a very low input resistance of 0.07 Ω.     

Power generation and cooling capacity enhancement of natural gas processing facilities in harsh environmental conditions through waste heat utilization

Most natural gas (NG) producers in the Persian Gulf face increasing challenges in meeting their domestic gas demands and therefore seek to reduce their NG consumption. Concurrently, the on‐site power generation and cooling capacities of local NG processing facilities are constrained by extreme climatic conditions. A combined cooling and power scheme based on gas turbine (GT) waste heat‐powered absorption refrigeration is techno‐economically assessed to reduce the NG consumption of a major gas processing plant in the Persian Gulf. The scheme utilizes double‐effect water‐lithium bromide absorption refrigeration activated by steam generated from GT exhaust gas waste heat to provide both GT compressor inlet air and process gas cooling. Based on a thermodynamic analysis, recovery of 150 MW of GT waste heat is found to enhance the plant cooling capacity by 195 MW, thereby permitting elimination of a 32.6 MW GT and existing cooling equipment. On‐site power generation is enhanced by 196 GWh annually through GT compressor inlet air cooling, with energy efficiency (i.e., 64%) improved by 35% using cogeneration relative to the existing power generation plant. The overall net annual operating expenditure savings contributed by the combined cooling and power system are of $US13 million to 34 million based on present and projected local utility prices, with an economic payback period estimated at 2 to 5 years. These savings translate to approximately 94 to 241 MMSCM of NG per year, highlighting the potential of absorption refrigeration to both enhance the power generation and cooling capacity of hydrocarbon processing plants exposed to harsh environmental conditions and to realize substantial primary energy savings. Copyright © 2014 John Wiley & Sons, Ltd.     

Sex differences in jealousy over Facebook activity

Forty heterosexual undergraduate students (24 females, 16 males) who were currently in a romantic relationship filled out a modified version of The Facebook Jealousy questionnaire (Muise, Christofides, & Desmarais, 2009). The questionnaire was filled out twice, once with the participant’s own personal responses, and a second time with what each participant imagined that his/her romantic partner’s responses would be like. The data indicated that females were more prone to Facebook-evoked feelings of jealousy and to jealousy-motivated behavior than males. Males accurately predicted these sex differences in response to the jealousy scale, but females seemed unaware that their male partners would be less jealous than themselves.