The role of quantitative information about slip and grip force in prosthetic grasp stability

Prosthetic hands introduce an artificial sensorimotor interface between the prosthesis wearer and the environment that is prone to perturbations. We analyze theoretically and evaluate psychophysically the performance in stable grip control in conditions of physical grasps perturbation, such as object slip. Simulation results suggest that user-centered stable grasp control depends on two primal user parameters: reaction time to slip and grip force intensity. Experiments with human users indicate that a user’s response time can be controlled by relaying information about the speed of the slipping object, while minimal grip force intensity can be adjusted with information about grip force at the onset of the slip. Based on our theoretical and experimental findings, we propose a stable grasp control method for prosthetic hands.     

Free Liquid Jet Impingement from a Slot Nozzle to a Curved Plate

This article explores the heat transfer characteristics of a free liquid jet discharging from a slot nozzle and impinging vertically on a curved cylindrical shaped plate of finite thickness. Computations were done for Re = 500–1800, β = 0.75–3, R _i /d _n  = 4.16–16.66, b/d _n  = 0.08–1.5, and d _n  = 0.3–2.4 mm. Results are presented for dimensionless solid–fluid interface temperature, dimensionless maximum temperature in the solid, and local and average Nusselt numbers. The local Nusselt number increases with Reynolds number. Decreasing the nozzle width increases the local heat transfer coefficient. Decreasing the nozzle to target spacing or plate thickness or plate inner radius of curvature all enhances the Nusselt number.     

Modulation of biotransformation and elimination systems by BM-21, an aqueous ethanolic extract from Thalassia testudinum,and thalassiolin B on human hepatocytes

BM-21 is an extract obtained from Thalassia testudinum marine plant with pharmacological properties. The effects of BM-21 and thalassiolin B (TB), its main component, on enzyme and transport proteins involved in drug metabolism and excretion in human cultured hepatocytes were evaluated. Cells were exposed for 48 h to sub-cytotoxic concentrations of BM-21 or TB. Effects on P450 isoforms revealed significant reductions of CYP1A2, 3A4 and 2D6 activities (up to 56%, 66% and 44% inhibition, respectively) after exposition to BM-21, no changes on CYP2A6 and 2C9 activities. TB produced a concentration-dependent reduction of all P450 activities. In addition, a decrease in total UGT and UGT2B7 activities was found at 250 μg/mL BM-21, while UGT1A1 and 1A9 were significantly reduced (50 μg/mL). TB only inhibited significantly UGT1A9 activity. Both products were able to reduce P-gp activity in treated hepatocytes. Quantification of specific mRNAs revealed a reduction in CYP3A4 and 3A5 mRNAs content and an increase in CYP1A1 and 1A2 mRNAs. No appreciable effects in the levels of CYP2A6, 2B6, 2C9, 2C19, 2D6, 2E1, UGT1A1, UGT1A9 and ABCB1 (P-gp) were found. BM-21 inhibited P450, UGTs and P-gp activities in human hepatocytes; therefore, it should be examined for potential pharmacokinetic drug interactions in vivo.     

A Test Platform for Dependability Analysis of SoCs Exposed to EMI and Radiation

With the IEC 62.132 proposal, the roadmap for standardization of Electromagnetic (EM) immunity measurement methods has reached a high degree of success. The same understanding can be taken from the MIL-STD-883?H for Total Ionizing Dose (TID) radiation. However, no effort has been made to measure the behavior of electronics operating under the combined effects of both, EM noise and TID radiation. For the reasons pointed out, the combined-effect measurements should be mandatory when dealing with Systems-on-Chip (SoCs) devoted to critical applications. In this paper, we present a configurable platform devoted to perform combined tests of EM immunity and TID radiation of SoCs according to the international standards.     

New Configuration of Solid‐State Neutron Detector Made Possible with Solution‐Based Semiconductor Processing

The unique benefit of solution‐based fabrication of solid‐state p‐n junctions is demonstrated for radiation detection. In particular, an in situ inorganic semiconductor synthesis and film deposition facilitates a novel neutron detector configuration consisting of a host inorganic semiconductor matrix impregnated with a guest neutron sensitizing material. Spectroscopic investigations of the structural order of the top detector active layer indicate that it consists of interpenetrating networks of the host semiconductor nanocrystals and sensitizing guest material that self‐assemble during film formation. The host semiconductor network exhibits a good charge transport as evidenced by steady‐state photoconductivity measurements. The detectors developed indicate high sensitivity to ionizing radiation and a demonstrated ability to detecting thermal neutrons.     

Iterative finite element model updating in the time domain

An iterative time domain formulation for finite element model updating in structural dynamics is presented. The approach is supported on a derivation showing that the discrepancy between observations and model predictions can be expressed as a convolution between the state of the system and a sequence of pseudo-Markov parameters which are linear in the change of the free parameters. The approach is illustrated by updating all the stiffness and damping parameters of a twenty degree of freedom shear beam using four noise contaminated measurements.     

Short communication: Circulating serotonin (5-HT) concentrations on day 1 of lactation as a potential predictor of transition-related disorders

The monoamine serotonin (5-hydroxytryptamine; 5-HT) has been described as a homeostatic regulator of lactation. Recently, our laboratory determined that 5-HT is involved in the regulation of calcium and glucose homeostasis during the transition period in rodents. More specifically, we demonstrate that 5-HT is responsible for calcium mobilization from bone and upregulation of hepatic gluconeogenic enzymes and mammary gland glucose transporters. Our objective was to investigate the correlation between circulating 5-HT concentrations and circulating ionized calcium, parathyroid hormone-related protein (PTHrP), and glucose concentrations on d 1 postpartum. We also investigated the correlation between circulating 5-HT and milk fever and ketosis incidence and severity in multiparous Holstein cows at the onset of lactation. Blood samples were collected from 42 multiparous cows on d 1 of lactation and analyzed for 5-HT, calcium, glucose, and PTHrP. Milk fever (determined subjectively for each cow on d 1 postpartum) and ketosis incidence and severity (scale 1 to 4, determined objectively for each cow during the first 10 d postpartum) were recorded for all animals. Serum 5-HT was positively correlated with serum calcium and with plasma PTHrP (r > 0.37). Serum 5-HT was negatively correlated with milk fever incidence and with ketosis severity (most severe ketosis incidence recorded during the first 10 d postpartum; r < -0.33). Serum calcium and plasma glucose concentrations were negatively correlated with milk fever and ketosis severity, respectively (r < -0.39). These data indicate that 5-HT potentially plays a role in the regulation of calcium and glucose homeostasis during the transition period in cattle, which we previously demonstrated in rodents. Increased circulating concentrations of 5-HT might decrease milk fever at the onset of lactation and ketosis severity during the first 10 d postpartum in dairy cows. Understanding this physiological axis could help describe the underlying mechanisms associated with these periparturient metabolic disorders in dairy cows.     

Tempering of Martensite in Dual-Phase Steels and Its Effects on Softening Behavior

The isothermal and nonisothermal tempering of martensite in dual-phase (DP) steels was investigated mainly by analytical transmission electron microscopy, and the effect on softening behavior was studied. The isothermal tempering resulted in coarsening and spheroidization of cementite and complete recovery of laths. However, nonisothermal tempering manifested fine quasi-spherical intralath and platelike interlath cementite, decomposition of retained austenite, and partial recovery of laths. The distinct characteristic of nonisothermal tempering was primarily attributed to the synergistic effect of delay in cementite precipitation and insufficient time for diffusion of carbon due to rapid heating that delays the third stage of tempering. The finer size and platelike morphology of cementite coupled with partial recovery of lath resulted in reduced softening in nonisothermal tempering compared to severe softening in isothermal tempering due to large spheroidized cementite and complete recovery of lath substructure. The substitutional content of precipitated cementite in nonisothermal tempering was correlated to the richness of particular steel chemistry. Softening resistance during nonisothermal tempering was related to DP steel chemistry, i.e., Cr and Mn content. Fine cementite and less decomposed martensite in rich chemistry confer high resistance to softening compared to leaner chemistries, which indicated severe decomposition of martensite with coarser cementite.