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Mathematical Model for Pressure-Deformation Relationship of Miniaturized McKibben Actuators
No full textA McKibben actuator/Pneumatic Artificial Muscle (PAM) is a soft actuator which has great potential in the field of bioinspired robotics. Miniaturized versions of PAMs or MPAMs of less than 1.5 mm diameter are ideal actuators for developing surgical devices due to their compliance and high power-to-weight ratio. Accurate mathematical model to represent the mechanics of PAM is an ongoing research. This paper develops a mathematical model which relates the input pressure to end-point deformation of a fabricated MPAM without external loading. The developed theoretical model is validated against experimental data for MPAM of lengths 60 and 70 mm. The model predicts the deformation of MPAM with standard error of less than 10%. The model is also able to predict the locking angle of 54.7 degrees at higher pressures which is a distinct characteristic of McKibben actuators
ESD Reliability Study of a-Si:H Thin-Film Transistor Technology: Physical Insights and Technological Implications
No full textIn this paper, we present the detailed physical insights into the electrostatic discharge (ESD) behavior of hydrogenated amorphous silicon (a-Si:H)-based thin-film transistor (TFT) technology. Device failure under ESD conditions is studied in detail using electrical and optical techniques. Device degradation under ESD timescales is studied using real-time capacitance-voltage and a spatially variant degradation behavior is reported. Variations in material properties are studied before and after device failure using Raman spectroscopy. Device dimension-dependent failure mechanism is explored. Impact of stressing conditions and presence of top passivation on failure behavior is also explored. Failure physics of technologically relevant device architectures including diode-connected transistors (gated diodes) and drain underlap TFTs and their increased ESD robustness is discussed. Finally, ESD behavior of a-Si:H-based TFTs is discussed
Azimuthal separation in nearly back-to-back jet topologies in inclusive 2-and 3-jet events in pp collisions at root s=13TeV
No full textA measurement for inclusive 2- and 3-jet events of the azimuthal correlation between the two jets with the largest transverse momenta, Delta phi(12), is presented. The measurement considers events where the two leading jets are nearly collinear (''back-to-back'') in the transverse plane and is performed for several ranges of the leading jet transverse momentum. Proton-proton collision data collected with the CMS experiment at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 35.9 fb(-1) are used. Predictions based on calculations using matrix elements at leading-order and next-to-leading-order accuracy in perturbative quantum chromodynamics supplemented with leading-log parton showers and hadronization are generally in agreement with themeasurements. Discrepancies between the measurement and theoretical predictions are as large as 15%, mainly in the region 177 degrees < Delta phi(12) < 180 degrees. The 2- and 3-jet measurements are not simultaneously described by any of models
Search for MSSM Higgs bosons decaying to mu(+)mu(-) in proton-proton collisions at root s=13TeV
No full textA search is performed for neutral non-standard-model Higgs bosons decaying to two muons in the context of the minimal supersymmetric standard model (MSSM). Proton-proton collision data recorded by the CMS experiment at the CERN Large Hadron Collider at a center-of-mass energy of 13 TeV were used, corresponding to an integrated luminosity of 35.9 fb(-1). The search is sensitive to neutral Higgs bosons produced via the gluon fusion process or in association with a b (b) over bar quark pair. No significant deviations from the standard model expectation are observed. Upper limits at 95% confidence level are set in the context of the m(h)(mod+) and phenomenological MSSM scenarios on the parameter tan beta as a function of the mass of the pseudoscalar A boson, in the range from 130 to 600 GeV. The results are also used to set a model-independent limit on the product of the branching fraction for the decay into a muon pair and the cross section for the production of a scalar neutral boson, either via gluon fusion, or in association with b quarks, in the mass range from 130 to 1000 GeV
Composition and U-Pb ages of apatite in the Amba Dongar carbonatite-alkaline complex, India
No full textThe Amba Dongar carbonatite-alkaline complex is regarded as a late phase intrusion (ca. 65 Ma) associated with Deccan volcanism. Existing age constraints on the Amba Dongar carbonatite are based on phlogopite Ar-40-Ar-39 plateau ages derived from carbonatite and associated alkaline rocks within the complex. We explore the utility of apatite, a common accessory mineral in Amba Dongar carbonatites, as a petrogenetic and geochronological tool to constrain further the evolution of the carbonatites. Apatite exhibits different crystal forms-from hexagonal stubby prisms to ovoid and elongate grains. Apatite occurs as cumulate and disseminated grains that are either primary, fractured, or recrystallized. SrO content is high in primary apatite (3.17 wt%) but less in recrystallized (1.90 wt%) and disseminated grains (0.47 wt%). MnO and Cl are negligible while FeO is typically low in all samples. SiO2 content is low except for a few primary grains which measure up to 1.35 wt%, correlating with high REE content. LREEs dominate the total REE budget of Amba Dongar apatite, with HREEs below EPMA detection limit in most samples. Total REE content is generally low, though some primary apatite contains up to 3.19 wt% REEs. We also report U-Pb apatite ages from the carbonatites analysed in situ by LA-ICP-MS. The data from all samples combined on a U-Pb Tera-Wasserburg concordia yield a lower intercept age of 65.4 +/- 2.5 Ma (MSWD = 2.8, Pb-207/Pb-206(i) = 0.8272 +/- 0.0028), and the Amba Dongar carbonatites are thus interpreted to represent a phase of coeval magmatic activity with Deccan volcanism
Lactate reduces epileptiform activity through HCA1 and GIRK channel activation in rat subicular neurons in an in vitro model
No full textObjective Much evidence suggests that the subiculum plays a significant role in the regulation of epileptic activity. Lactate acts as a neuroprotective agent against many conditions that cause brain damage. During epileptic seizures, lactate formation reaches up to similar to 6 mmol/L in the brain. We investigated the effect of lactate on subicular pyramidal neurons after induction of epileptiform activity using 4-aminopyridine (4-AP-0Mg(2+)) in an in vitro epilepsy model in rats. The signaling mechanism associated with the suppression of epileptiform discharges by lactate was also investigated. Methods We used patch clamp electrophysiology recordings on rat subicular neurons of acute hippocampal slices. Immunohistochemistry was used for demonstrating the expression of hydroxycarboxylic acid receptor 1 (HCA1) in the subiculum. Results Our study showed that application of 6 mmol/L lactate after induction of epileptiform activity reduced spike frequency (control 2.5 +/- 1.23 Hz vs lactate 1.01 +/- 0.91 Hz, P = .049) and hyperpolarized the subicular neurons (control -51.8 +/- 1.9 mV vs lactate -57.2 +/- 3.56 mV, P = .002) in whole cell patch-clamp experiments. After confirming the expression of HCA1 in subicular neurons, we demonstrated that lactate-mediated effect occurs via HCA1 by using its specific agonist. All values are mean +/- SD. Electrophysiological recordings revealed the involvement of G beta gamma and intracellular cAMP in the lactate-induced effect. Furthermore, current-clamp and voltage-clamp experiments showed that the G protein-coupled inwardly rectifying potassium (GIRK) channel blocker tertiapin-Q, negated the lactate-induced inhibitory effect, which confirmed that lactate application results in outward GIRK current. Significance Our finding points toward the potential role of lactate as an anticonvulsant by showing lactate-induced suppression of epileptiform activity in subicular neurons. The study gives a different insight by suggesting importance of endogenous metabolite and associated signaling factors, which can aid in improving the present therapeutic approach for treating epilepsy
Targeting redox heterogeneity to counteract drug tolerance in replicating Mycobacterium tuberculosis
No full textThe capacity of Mycobacterium tuberculosis (Mtb) to tolerate multiple antibiotics represents a major problem in tuberculosis (TB) management. Heterogeneity in Mtb populations is one of the factors that drives antibiotic tolerance during infection. However, the mechanisms underpinning this variation in bacterial population remain poorly understood. Here, we show that phagosomal acidification alters the redox physiology of Mtb to generate a population of replicating bacteria that display drug tolerance during infection. RNA sequencing of this redox-altered population revealed the involvement of iron-sulfur (Fe-S) cluster biogenesis, hydrogen sulfide (H2S) gas, and drug efflux pumps in antibiotic tolerance. The fraction of the pH- and redox-dependent tolerant population increased when Mtb infected macrophages with actively replicating HIV-1, suggesting that redox heterogeneity could contribute to high rates of TB therapy failure during HIV-TB coinfection. Pharmacological inhibition of phagosomal acidification by the antimalarial drug chloroquine (CQ) eradicated drug-tolerant Mtb, ameliorated lung pathology, and reduced post-chemotherapeutic relapse in in vivo models. The pharmacological profile of CQ (C-max and AUC(last)) exhibited no major drug-drug interaction when coadministered with first line anti-TB drugs in mice. Our data establish a link between phagosomal pH, redox metabolism, and drug tolerance in replicating Mtb and suggest repositioning of CQ to shorten TB therapy and achieve a relapse-free cure
An in situ monitored and controlled etch process to suppress Mg memory effects in MOCVD GaN growth on Si substrate
No full textMg is the most common p-type dopant in III-nitride devices and is becoming increasingly important in the design and development of transistors for power applications. The diffusion of Mg atoms to adjacent layers during growth has been a persistent problem. We report on a simple method involving in situ etching by hydrogen, the most commonly used carrier gas in nitride growth, for suppressing Mg diffusion. This method can be implemented during growth itself without removing the wafer from the chamber and can be controlled by in situ monitoring. A Mg concentration decay rate of 24 nm/dec, is reported for the etched sample compared to 160 nm/dec for the unetched one. An increase in 2DEG mobility in AlGaN/GaN HEMT structures on silicon substrate from 591 cm(2) V-?1 s(?1) for the unetched sample to 1214 cm(2) V(?1 )s(?1 )for the etched sample was observed. Capacitance?voltage studies to understand the effect of diffused Mg atoms on conduction channel are also reported
Search for long-lived particles using delayed photons in proton-proton collisions at root s=13 TeV
No full textA search for long-lived particles decaying to photons and weakly interacting particles, using protonproton collision data at root s = 13 TeV collected by the CMS experiment in 2016-2017 is presented. The data set corresponds to an integrated luminosity of 77.4 fb(-1). Results are interpreted in the context of supersymmetry with gauge-mediated supersymmetry breaking, where the neutralino is long-lived and decays to a photon and a gravitino. Limits are presented as a function of the neutralino proper decay length and mass. For neutralino proper decay lengths of 0.1, 1, 10, and 100 m, masses up to 320, 525, 360, and 215 GeV are excluded at 95% confidence level, respectively. We extend the previous best limits in the neutralino proper decay length by up to one order of magnitude, and in the neutralino mass by up to 100 GeV
Designing M-bond (X-M center dot center dot center dot Y, M = transition metal): sigma-hole and radial density distribution
No full textFollowing the ubiquitous H-bond, there is a growing interest in weak non-covalent interactions involving other elements, viz., the Z-bonds (X-Z center dot center dot center dot Y, Z = halogens, chalcogens, etc.). Although almost all the main group elements can act as Z bond donors, the search for a similar role for transition metals in X-M center dot center dot center dot Y, (M = transition metal) interaction, called the Metal-bond, is still in its infancy. This article summarizes our attempts to understand the participation of transition metal elements as electron acceptors in a weak interaction with electron-rich species Y. Cambridge Structural Database analysis revealed that except Group 11 and 12 transition metal complexes (Type-II), electron-saturated (18 electron) metal complexes having partly filled d orbitals (Group 3-10; Type-I) hesitate to form Metal-bonds. This is attributed to the partial sigma-hole screening by core electron density and diminished stabilization from charge polarization in Type I complexes. We also show that Type-I complexes could be forced to form Metal-bonds by employing extreme ligand conditions, thereby opening new areas of research where Metal-bonds can act as emerging non-covalent interaction in designing supramolecular architectures