A universal six-joint robot controller

A general purpose six-axis robotic manipulator controller was designed and implemented to serve as a research tool for the investigation of the practical and theoretical aspects of various control strategies in robotics. A 80286-based Intel System 310 running the Xenix operating servo software as well as the higher level software (e.g., kinematics and path planning) were employed. A Multibus compatible interface board was designed and constructed to handle I/O signals from the robot manipulator's joint motors. From the design point of view, the universal controller is capable of driving robot manipulators equipped with D.C. joint motors and position optical encoders. To test its functionality, the controller is connected to the joint motor D.C. power amplifier of a PUMA 560 arm bypassing completely the manufacturer-supplied Unimation controller. A controller algorithm consisting of local PD control laws was written and installed into the Xenix operating system. Additional software drivers were implemented to allow application programs access to the interface board. All software was written in the C language

Effects of thyroid hormone on HSV-1 gene regulation: implications in the control of viral latency and reactivation

Thyroid hormone (TH) is involved in many biological functions such as animal development, cell differentiation, etc. Variation and/or disruption of plasma TH level often led to abnormalities and physiological disorders. TH exerts the effects through its nuclear receptors (TR). Literature showed that procedures resulted in TH alteration also linked to reactivation of several viruses including Herpes Simplex Virus Type -1 (HSV-1). Bioinformatic analyses revealed a number of putative TH responsive elements (TRE) located in the critical regulatory regions of HSV-1 genes such as thymidine kinase (TK), latency associated transcript (LAT), etc. Studies using neuronal cell lines have provided evidences demonstrating that liganded TR regulated viral gene expression via chromatin modification and controlled viral replication. The removal of TH reversed the inhibition and induced the viral replication previously blocked by TH. These results suggest that TH may have implication to participate in the control of reactivation during HSV-1 latency

Medical abortion with mifepristone and vaginal misoprostol between 64 and 70 days' gestation.

ObjectiveTo evaluate outcomes with mifepristone 200 mg orally followed 24-48 h later by misoprostol 800 mcg vaginally for medical abortion at 64-70 days of gestation.Study designWe reviewed electronic databases and medical records for medical abortion cases at 64-70 days' gestation at British Pregnancy Advisory Service clinics in England and Wales from May 2015 through October 2016. Women selected in-office follow-up or self-evaluation of abortion outcome using a checklist along with low-sensitivity urine pregnancy testing. We excluded cases in which we could not locate records and when women did not proceed with medical abortion, did not use misoprostol following mifepristone if abortion had not occurred and did not attend a scheduled follow-up assessment. We analyzed demographic characteristics, treatment outcomes and significant adverse events. We defined treatment success as complete abortion without surgical evacuation and without continuing pregnancy.ResultsOf 2743 cases identified, we could not locate 40 charts and excluded 30 cases, leaving a final sample of 2673. Overall, 2538 (94.9%, 95% CI 94.1-95.8) women had a successful medical abortion. Reasons for failure included continuing pregnancy (n=90, 3.4%, 95% CI 2.7-4.1), retained nonviable pregnancy (n=2, 0.1%, 95% CI 0-0.2) and incomplete abortion (n=43, 1.6%, 95% CI 1.1-2.1). Of those with continuing pregnancies, 81 underwent a uterine aspiration and 9 opted to continue the pregnancy. Thirty-five (1.3%, 95% CI 0.9-1.7) women had significant adverse events; 16 (0.6%, 95% CI 0.3-0.9) underwent an in-hospital aspiration. Pelvic infection (n=4, 0.2%) and transfusion (n=1, 0.03%) occurred rarely.ConclusionMedical abortion from 64 to 70 days with mifepristone and vaginal misoprostol is effective with a low rate of serious adverse events.ImplicationsMedical abortion between 64 and 70 days of gestation may be offered on an outpatient basis using mifepristone and vaginal misoprostol. Service provision without an in-person follow-up is feasible. Not all women with a continuing pregnancy after medical abortion treatment opt to have an aspiration procedure

Wear particle dynamics drive the difference between repeated and non-repeated reciprocated sliding

The dependence of the sliding mode (repeated vs. non-repeated reciprocated sliding) on the friction and wear behavior of ball-on-flat, brittle non-metallic interfaces in ambient air conditions is evaluated. Repeated sliding promotes the formation of a third body (compressed wear particles) that stabilizes the friction. Non-repeated sliding shows reduced evidence of third body formation, and instead a steady increase in friction. The proposed mechanism driving the non-repeated friction behavior is attributed to a gradual reduction in the ball surface roughness, leading to an increased area of real contact and greater capillary bridge forming across non-contact regions of the interface

Molecular Probing of the Stress Activation Volume in Vapor Phase Lubricated Friction

When two solid objects slide over each other, friction results from the interactions between the asperities of the (invariably rough) surfaces. Lubrication happens when viscous lubricants separate the two surfaces and carry the load such that solid-on-solid contacts are avoided. Yet, even small amounts of low-viscosity lubricants can still significantly lower friction through a process called boundary lubrication. Understanding the origin of the boundary lubricating effect is hampered by challenges in measuring the interfacial properties of lubricants directly between the two surfaces. Here, we use rigidochromic fluorescent probe molecules to measure precisely what happens on a molecular scale during vapor-phase boundary lubrication of a polymer bead-on-glass interface. The probe molecules have a longer fluorescence lifetime in a confined environment, which allows one to measure the area of real contact between rough surfaces and infer the shear stress at the lubricated interfaces. The latter is shown to be proportional to the inverse of the local interfacial free volume determined using the measured fluorescence lifetime. The free volume can then be used in an Eyring-type model as the stress activation volume, allowing to collapse the data of stress as a function of sliding velocity and partial pressure of the vapor phase lubricant. This shows directly that as more boundary lubricant is applied, larger clusters of lubricant molecules become involved in the shear process thereby lowering the friction.</p