Regulation of a Physiological Parameter or In Vivo Drug Concentration by Integral Pulse Frequency Modulated Bolus Drug Injections

This paper describes the designs for two novel, nonlinear, discrete, drug injection controllers. The basis for these controllers is integral pulse frequency modulation (IPFM). An IPFM controller injects small boluses of a drug into a pharmacokinetic (PK) plant to achieve regulation of the plant output. Bolus injections are advantageous because they provide a precise knowledge of the times and the cumulative amount of drug injected, and they require a discrete-action pump suitable for digital control, miniaturization, and implantation.     

High performance GaAs MESFETs with molecular implanted and optimized lowly-doped drain structure for maximized speed, gain and breakdown performance

GaAs MESFETs with novel lowly-doped drain structures have been developed utilizing molecular implants of silicon trifluoride. Short-channel effects in the 1/4 μm enhancement- and depletion-mode transistors have been suppressed with drain-induced barrier height lowering of less than 70 mV/V and pinch-off voltage shifts of less than 220 mV as the gate length was scaled from 1.0 to 1/4 μm. The 3-terminal breakdown, the transconductance to output conductance ratio, and the unity current gain, cut-off frequency were simultaneously optimized. The E-mode device possessed breakdown of >10 V, G_m · R_ds > 9.5, F_t > 55 GHz, and nominal on-resistance of 2.1 Ω mm while the D-mode device had breakdown >10 V, G_m · R_ds > 6.0, F_t > 45 GHz, and nominal on-resistance of 1.9 Ω mm. These optimized transistors enabled the realization of a variety of low-power digital and high-power mixed signal circuits, using 3-level source-coupled transistor and common-mode logic, such as laser and electro-optic drivers, highly integrated transceivers, multiplexers, demultiplexers, and clock data recover circuits.     

Lesions of the dorsal spinal cord decrease the duration of contact defensive immobility (animal hypnosis) in the rabbit.

22 male New Zealand albino rabbits received either bilateral dorsal or unilateral dorsolateral spinal cord lesions. The duration and incidence of contact defensive immobility (CDI) were tested in these Ss and in 10 intact controls. Neither of the spinal cord lesions affected the number of CDI inductions, but Ss with lesions of the dorsal spinal cord exhibited significantly shorter durations of CDI than either of the other groups, which did not differ from each other. Results indicate that the somesthetic systems that ascend in the dorsal spinal cord are important for the maintenance, but not the initiation, of CDI. It is suggested that the reduction of excitatory drive to neurons of the reticular zones of the dorsal column nuclei produced by transection of the dorsal spinal cord provides the physical basis for the reduction of CDI duration. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Precision nutrition: weighing feed ingredients correctly

The ability to mix a quality feed is often equated to the quality of the mixer; the ability to weigh ingredients correctly has received little attention. To assess how accurately feed mills weigh their ingredients, 14 feed mills specialising in swine diets were surveyed, which yielded 8432 data points (for 229 ingredients and 11–44 batch records per ingredient within mills). Amounts actually weighed (according to scale readings) were compared to calls, and differences were analysed statistically. Feed mills overdosed ingredients by 1.5 ± 16.3%: between mills, overdosing ranged from ?0.7 to 13.0%. Within ingredients, weighing variation ranged from 0.6 to 11.1% between mills and averaged 5.2%. Some of the weighing problems observed were attributed to discrepancies between the call size and the scale resolution. For example, weighing 11.3 units (pounds) on a scale with a 2 unit resolution leads to a minimum error of 6%. Such problems occurred for 8.7% of the calls and resulted in a minimum error ranging from 0.01 to 20%, averaging 1.95%. Poor choice of scales was the major source of errors in weighing, and the relationship weighing variation = 10^∧ [1.56 ? 0.50 log (call/scale resolution)] explained 40% of the variation observed (p < 0.05). Weighing ingredients in the right scale would thus not only benefit feed quality but also reduce diet cost, as it would reduce the overdosing of ingredients. © 2001 Society of Chemical Industry     

Export of cryptographic information from the USA: A brief look at the problems

Ever wonder why many technologies that could benefit from cryptographic security frequently do not have such facilities? Network protocols are a prime example. Inclusion of end-to-end encryption would solve a great many problems with regards to the security of node-to-node communications. Of course, it also raises some other problems (such as key distribution systems), but these are made to be solved.     

Small signal modeling of GaAs PIN diodes aided by electromagnetic analysis

A systematic procedure is described for determination of GaAs PIN diode equivalent circuit models from measured S‐parameter data combined with an electromagnetic analysis of the feed structure. A new parasitic and intrinsic model topology is proposed, and found to be better suited than prior models for the particular GaAs PIN structures considered in this work. Models were developed for forward bias currents ranging from 0.01 to 100 mA, and example measured and modeled results are included to validate the approach. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 61–68, 2001.     

产品可靠性的重新下降？

不久前，我们的行业遇到了元件可靠性问题，大批量产品用户发现美国公司的存储器IC的故障率比日本同类产品高。通过努力，现在各类IC都很可靠，硬IC故障也很少。我们的其它元件．比如无源元件、印线电路板等，情况也大多是如此。     

Determinants of exercise intention and behavior during and after phase 2 cardiac rehabilitation: An application of the theory of planned behavior.

Objective: To evaluate the theory of planned behavior (TPB) as a framework for understanding exercise motivation during and after Phase 2 cardiac rehabilitation (CR). Design and Participants: Patients (57 men and 24 women) completed a TPB questionnaire that included attitudes, subjective norms, perceived behavioral control, and exercise intentions pre- and post-Phase 2 CR. Results: During Phase 2 CR, regression analyses indicated that attitude, subjective norm, and perceived behavioral control (PBC) explained 38% of the variance in exercise intention while intention explained 23% of the variance in exercise adherence. At postrehabilitation follow-up, attitudes, subjective norm, and PBC explained 51 % of the variance in exercise intention while intention explained 23% of the variance in exercise adherence. Conclusion: The TPB is a useful framework for understanding exercise intentions and behavior both during and after Phase 2 CR. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MIQR Active Learning on a Continuous Function and a Discontinuous Function

Active learning balances the cost of data acquisition against its usefulness for training. We select only those data points which are the most informative about the system being modelled. The MIQR (Maximum Inter-Quartile Range) criterion is defined by computing the inter-quartile range of the outputs of an ensemble of networks, and finding the input parameter values for which this is maximal. This method ensures data selection is not unduly influenced by ‘outliers’, but is principally dependent upon the ‘mainstream’ state of the ensemble. MIQR is more effective and efficient than contending methods¹ . The algorithm automatically regulates the training threshold and the network architecture as necessary. We compare active learning methods by applying them to a continuous function and a discontinuous function. Training is more difficult for a discontinuous function than a continuous function, and the volume of data for active learning is substantially less than for passive learning.