Influence of temperature on the rate of post-mortem metabolism and water-holding capacity of bovine neck muscles

Strips of forty bovine neck muscles were placed at temperatures in the range -1° to +30°C within 45 min of slaughter and stored for up to 24 h. Strips were taken at various times during storage and assayed for pH, 'R' value (degree of transformation of ATP to IMP) and ATP concentration. The water-holding capacity (WHC) of the intact muscle was compared with the WHC of a salted muscle homogenate prepared at each sampling time. The rate of pH fall post mortem was relatively low around +5°C and increased at lower or higher temperatures. ATP concentration showed a delay phase dependent on storage temperature and a subsequent rate of depletion which was also temperature dependent. The patterns of change in WHC of the muscle samples and the salted homogenates differed, the former showing a rapid fall to a fairly steady level shortly after initiation of storage, the latter showing no appreciable change until the onset of rigor. It is suggested that salting meat at any time prior to the onset of rigor will confer improved WHC and that the temperature of storage post mortem should be chosen to induce low rates of ATP turnover so as to prolong the feasible delay between slaughter and salting.     

Rotated object identification with and without orientation cues.

The time to name two-dimensional line drawings of objects increases linearly for object rotations between 00 and 1200 from the upright. Several theories attribute these effects of orientation to finding the top or the top-bottom axis of objects. By this account, prior knowledge of the location of the top or the top-bottom axis of objects should diminish effects of object orientation when they are named. When this hypothesis was tested by cuing the top or the top-bottom axis, no reduction in the effects of orientation on object naming was found. This result is inconsistent with effects of orientation on object naming being due to finding the top or the top-bottom axis. Instead, the top may be found prior to rotational normalization of the object image. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wideband HBT circuits for operation above 10 GHz and power supply voltages below 5 V

Single-stage and two-stage differential cascode amplifiers, and a 2:1 multiplexer, fabricated in InP/InGaAs HBT technology and powered from less than 5 V supplies, are presented. The amplifiers have typical DC gains of 21 and 33 dB, respectively, and unity-gain bandwidths in excess of 15 GHz, with approximately 20 dB gain at 10 GHz. The multiplexer was tested at rates up to 20 Gbit/s.<>     

Activation of transducin guanosine triphosphatase by two proteins of the RGS family

RGS proteins (regulators of G protein signaling) constitute a newly appreciated group of negative regulators of G protein signaling. Several members of this group stimulate the guanosine triphosphatase (GTPase) activity of various G protein alpha-subunits, including the photoreceptor G protein, transducin. In photoreceptor cells transducin GTPase is known to be substantially accelerated by the coordinated action of the gamma-subunit of its effector enzyme, cGMP phosphodiesterase (PDE gamma), and another yet unidentified membrane-associated protein factor. Here we test the possibility that this factor belongs to the RGS family of GTPase stimulators. We report a detailed kinetic analysis of transducin GTPase activation by two members of the RGS family, RGS4 and G alpha interacting protein (GAIP). RGS4, being at least 5-fold more potent than GAIP, stimulates the rate of transducin GTPase by 2 orders of magnitude. Neither RGS4 nor GAIP requires PDE gamma for activating transducin. Rather, PDE gamma causes a partial reversal of transducin GTPase activation by RGS proteins. The effect of PDE gamma is based on a decreased apparent affinity of RGS for the alpha-subunit of transducin. Our observations indicate that GTPase activity of transducin can be activated by at least two distinct mechanisms, one based on the action of RGS proteins alone and another involving the cooperative action of the effector enzyme and another protein.     

Immersion plating of copper onto porous silicon with different thickness

This work aims to detail the mass change of a porous silicon sample during copper immersion plating. Gravimetric measurements and quantification of the deposited copper by induced coupled plasma spectroscopy (ICP) permit to separate the contributions to the mass change. The results indicate that immersion plating proceeds independently of the porous layer thickness at short immersion time. However, after long immersion duration, the deposition stops and thick porous layers are not fully oxidised. The oxidation of the porous layer is homogeneous and proceeds in depth with time, down to several micrometers.     

Microwave noise performance of InP/InGaAs heterostructure bipolartransistors

The authors report the first low-noise InP/InGaAs heterostructure bipolar transistor (HBT). Minimum noise figures of 0.46, 2.0, and 3.33 dB were measured at 2, 10, and 18 GHz, respectively. The noise performance of this InP/InGaAs HBT with an emitter size of 3.5×3.5 μm² is compared to that for FETs having a 1-μm gate length. The measured minimum noise figures agree well with calculated data using a modified Hawkins model. Broadband low-noise operation is observed because of the short transit time for injected nonequilibrium electrons to transverse the base and collector depletion region     

Patient education--support--help with decisions: ethical aspects in treatment of amyotrophic lateral sclerosis

Patients with amyotrophic lateral sclerosis (ALS) develop progressive, degenerative loss of muscle function while retaining mental capacity. This implies special problems of patient information, which should be phase-adapted and patient centered. The difficult task of the physicians requires to provide sufficient information, to enable shared decision-making, without leaving the patient alone. Respiratory failure due to loss of muscle function is often the limiting problem. However, the possible option of ventilatory support opens the question when to stop treatment. It is most important to differentiate between intended mercy-killing and foregoing treatment due to the patient's wish. Discontinuation of treatment is morally justifiable, even required, if the patient refuses further treatment. Advance directives may be helpful to make decisions according to patients' preferences in time.