Interaction affinity between cytokine receptor components on the cell surface

The anti-common gamma chain (gammac) mAb CP.B8 is shown to inhibit interleukin 4 (IL-4)-dependent proliferation of phytohemagglutinin (PHA) activated T cells noncompetitively with respect to cytokine by blocking the IL-4-induced heterodimerization of IL-4Ralpha and gammac receptor chains. Affinities for the binding of IL-4 to Cos-7 cells transfected with huIL-4Ralpha, and to PHA blasts expressing both IL-4Ralpha and gammac, were used to estimate the affinity of the key interaction between gammac and the binary IL-4Ralpha.IL-4 complex on the cell surface. This affinity was defined in terms of the dimensionless ratio [IL-4Ralpha.IL-4.gammac]/[IL-4Ralpha.IL-4], which we designate KR. The results show that on PHA blasts this interaction is relatively weak; KR approximately 9, implying that approximately 10% of the limiting IL-4Ralpha chain remains free of gammac even at saturating concentrations of IL-4. This quantitative treatment establishes KR as a key measure of the coupling between ligand binding and receptor activation, providing a basis for functional distinctions between different receptors that are activated by ligand-induced receptor dimerization.     

A differential deficit in time- versus event-based prospective memory in Parkinson's disease.

Objective: The aim of the current study was to clarify the nature and extent of impairment in time- versus event-based prospective memory in Parkinson's disease (PD). Prospective memory is thought to involve cognitive processes that are mediated by prefrontal systems and are executive in nature. Given that individuals with PD frequently show executive dysfunction, it is important to determine whether these individuals may have deficits in prospective memory that could impact daily functions, such as taking medications. Although it has been reported that individuals with PD evidence impairment in prospective memory, it is still unclear whether they show a greater deficit for time- versus event-based cues. Method: Fifty-four individuals with PD and 34 demographically similar healthy adults were administered a standardized measure of prospective memory that allows for a direct comparison of time-based and event-based cues. In addition, participants were administered a series of standardized measures of retrospective memory and executive functions. Results: Individuals with PD demonstrated impaired prospective memory performance compared to the healthy adults, with a greater impairment demonstrated for the time-based tasks. Time-based prospective memory performance was moderately correlated with measures of executive functioning, but only the Stroop Neuropsychological Screening Test emerged as a unique predictor in a linear regression. Conclusions: Findings are interpreted within the context of McDaniel and Einstein's (2000) multiprocess theory to suggest that individuals with PD experience particular difficulty executing a future intention when the cue to execute the prescribed intention requires higher levels of executive control. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A novel parametric-effect MEMS amplifier

This paper presents the theory and measurements of a mechanical parametric-effect amplifier with a 200-kHz input signal and a 1.84-MHz output signal. The device used is a MEMS time-varying capacitor which is composed of an array of low-stress metallized silicon-nitride diaphragms, and is pumped by a large-signal voltage at 1.64 MHz. This induces a large change in the capacitance, and results in parametric amplification of an input signal at 200 kHz. The parametric amplifier capacitance is 500 pF, resulting in an output impedance of 140 Ω. A higher impedance can also be achieved with a lower capacitance. To our knowledge, this device is the first-ever MEMS mechanical up-converter parametric-effect amplifier developed with an up-conversion ratio of 9:1. The measurements agree very well with theory, including the effect the series resistance and the and of the MEMS time-varying capacitor. The application areas are in amplifiers which operate at very high temperatures (200°C-600°C), under high particle bombardment (nuclear applications), in non-semiconductor-based amplification, and in low-noise systems, since parametric amplifiers do not suffer from thermal, shot, or 1/f noise problems     

Exploiting structure in LTL synthesis

In this paper, we show how to exploit the structure of some automata-based construction to efficiently solve the LTL synthesis problem. We focus on a construction proposed in Schewe and Finkbeiner that reduces the synthesis problem to a safety game, which can then be solved by computing the solution of the classical fixpoint equation νX.Safe ∩ CPre(X), where CPre(X) are the controllable predecessors of X. We have shown in previous works that the sets computed during the fixpoint algorithm can be equipped with a partial order that allows one to represent them very compactly, by the antichain of their maximal elements. However the computation of CPre(X) cannot be done in polynomial time when X is represented by an antichain (unless P = NP). This motivates the use of SAT solvers to compute CPre(X). Also, we show that the CPre operator can be replaced by a weaker operator CPre _crit where the adversary is restricted to play a subset of critical signals. We show that the fixpoints of the two operators coincide, and so, instead of applying iteratively CPre, we can apply iteratively CPre _crit. In practice, this leads to important improvements on previous LTL synthesis methods. The reduction to SAT problems and the weakening of the CPre operator into CPre _crit and their performance evaluations are new.     

SOI-CMOS compatible low-power gas sensor using sputtered and drop-coated metal-oxide active layers

In this paper, a Silicon-On-Insulator (SOI) solid-state gas-sensor with an original design of a polysilicon loop-shaped microheater fabricated on a thin-stacked dielectric membrane is presented. The microheater ensures high thermal uniformity and very low power consumption (25 mW for heating at 400°C). Sensitive films are based on tin and tungsten oxides deposited either by RF sputtering or drop coating methods. The fabricated sensors are tested to a wide variety of contaminant species and promising results are obtained. The use of completely CMOS compatible TMAH-based bulk micro-machining techniques during the fabrication process, allows easy smart gas sensor integration in SOI-CMOS technology. This makes SOI-based gas-sensing devices particularly attractive for use in handheld battery-operated gas monitors.     

Spin-on spintronics: ultrafast electron spin dynamics in ZnO and Zn₁-xCoxO sol-gel films

We use time-resolved Faraday rotation spectroscopy to probe the electron spin dynamics in ZnO and magnetically doped Zn(1-x)Co(x)O sol-gel thin films. In undoped ZnO, we observe an anomalous temperature dependence of the ensemble spin dephasing time T(2), i.e., longer coherence times at higher temperatures, reaching T(2) ～ 1.2 ns at room temperature. Time-resolved transmission measurements suggest that this effect arises from hole trapping at grain surfaces. Deliberate addition of Co(2+) to ZnO increases the effective electron Lande? g factor, providing the first direct determination of the mean-field electron-Co(2+) exchange energy in Zn(1-x)Co(x)O (N(0)α = +0.25 ± 0.02 eV). In Zn(1-x)Co(x)O, T(2) also increases with increasing temperature, allowing spin precession to be observed even at room temperature.     

Simulation of precision calorimeters in isothermal jackets

Conclusions A refined model for calorimetric systems with isothermal jackets is described and an analytical representation obtained for temperature fields of such systems, which relates temperature to the basic parameters affecting the calorimeter heat-exchange processes.Translated from Izmeritel'naya Tekhnika, No. 8, pp. 66–69, August, 1977.     

DNA fingerprinting of Mycobacterium tuberculosis complex culture isolates collected in Brazil and spotted onto filter paper

The usefulness of filter paper for preservation of bacterial cells was shown by mixed-linker DNA fingerprint analysis of Mycobacterium tuberculosis isolates from 77 Brazilian patients. DNA fingerprints of samples spotted onto filter paper and conventional culture material were identical. Thus, filter paper specimens analyzed by an amplification-based typing method provide a new resource for epidemiological studies of infectious diseases.     

Physiological measures and the detection of deception.

Evaluates laboratory research on physiological measures for detecting deception. The general problems encountered in making inferences about truth and deception from physiological recordings are described, and various methods for designing tests of deception are explained and evaluated in light of these problems. It is concluded that a number of cardiovascular, electrodermal, and respiratory measures have been shown to be effective in discriminating between truth and deception. Other promising measures are identified, along with suggestions for conducting laboratory research that will be maximally generalizable to field applications of detection of deception. (66 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)