Space charge profile measurement techniques: recent advances and future directions

Some of the advances in space charge measurement techniques over the last 5 years are described. It is concluded that significant further improvements in spatial resolution are unlikely in the next 5 years, except in the case of the LIMM technique implemented using very short laser pulses, where spatial resolution approaching 100 nm might be achievable. It is suggested that existing space charge techniques be combined with conducting atomic force microscopy (CAFM), with the aim of correlating 3-dimensional space charge profiles and 2-dimensional conductivity maps and thus providing a more complete picture of charge transport through dielectrics, particularly in future work on nanodielectrics. Since CAFM samples are typically 5-10 nm thick, it would be necessary to operate the equipment at higher voltage (say 1000 V) so that samples not less than 10 /spl mu/m thick, e.g. polymers, could be investigated. This seems feasible.     

Detection of antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: a comparison of the alkaline phosphatase and immunofluorescent techniques

SSCP (single-strand conformational polymorphism) is used widely in the field of human biomedicine, but its potential as a population genetics tool for the recovery of nuclear gene genealogies remains to be realized. We describe and illustrate a use for SSCP in the physical isolation of nuclear haplotypes that circumvents several difficulties associated with more conventional cloning procedures. The DNA sequence can be determined directly from the isolated haplotypes and used for phylogenetic inference. SSCP provides a convenient first step toward generating nuclear genealogies for population studies.     

Effects of exogenous recombinant ovine interferon tau on circulating concentrations of progesterone, cortisol, luteinizing hormone, and antiviral activity; interestrous interval; rectal temperature; and uterine response to oxytocin in cyclic ewes

Interferon tau (IFN tau) is the conceptus-produced antiluteolytic signal in ruminants. Three experiments examined the effects of s.c. administration of recombinant ovine (ro)IFN tau on interestrous interval (IEI), oxytocin (OT)-induced uterine prostaglandin F2alpha metabolite (PGFM) production, rectal temperature (RT), respiration rate (RR), and plasma concentrations of progesterone, cortisol, LH, and antiviral activity (AVA) in plasma and uterine flushings. In experiment I, 20 ewes were treated s.c. with either 0, 1, 2, or 4 mg/day roIFN tau (0.7 x 10(8) U/mg; 5 ewes/dosage) from Days 11 to 15 of the estrous cycle (estrus = Day 0) and were challenged with OT (30 IU) on Day 15. Jugular blood samples were collected at -10, 0, 10, 20, 30, 40, 50, and 60 min relative to the OT challenge and assayed for PGFM. Recombinant oIFN tau increased IEI (16.7, 18.7, and 22.6 +/- 0.6 days for 0, 2, and 4 mg roIFN tau, respectively, p < 0.01). Recombinant oIFN tau did not affect peak PGFM response to OT (2309 +/- 172 pg/ml; p > 0.1). However, the 4 mg/day dosage delayed the time to peak PGFM (32.4 vs. 47.5 +/- 3.4 min; p < 0.01, 0 vs. 4 mg) and resulted in approximately 200% higher concentrations of PGFM at 60 min post-OT (0 vs. 4 mg/day, p < 0.07). Experiment II was similar to experiment I, except that only the 0- and 4-mg/day dosages of roIFN tau were administered. Ewes were hysterectomized on Day 16, and assay of uterine flushes detected no AVA from ewes treated with either 0 or 4 mg/day roIFN tau. In experiment III, 20 ewes were treated s.c. with either 0, 2, 4, or 6 mg roIFN tau on Day 12. Blood samples, RT, and RR were obtained at frequent intervals for 24 h, and plasma was assayed for progesterone, cortisol, LH, and AVA. Plasma AVA, which increased in a dose-dependent manner, was detectable within 60 min and remained elevated at 24 h compared to control values. RT (elevated 0.5-1.0 degrees C), RR, and cortisol increased in response to all dosages of roIFN tau, with peak values occurring 150-180 min postinjection. For all dosages of roIFN tau, plasma progesterone declined from 120 to 360 min posttreatment and then returned to pretreatment values by 24 h (p < 0.01) as compared to controls. Overall, exogenous roIFN tau altered uterine PGFM response to OT from a pulse to a gradual and sustained elevation and extended IEI with only a transient decline in progesterone and mild hyperthermia, effects that are not expected to compromise pregnancy.     

Piecewise monotone filtering in discrete-time with smallobservation noise

A discrete-time model for filtering with small observation noise is considered. A piecewise linear observation function is considered with two intervals of monotonicity. A sequential quadratic variation test is found to detect intervals of linearity of the observation function. Diffusion approximations to certain discrete processes are made to estimate the mean times for reaching a decision and the error probabilities     

Constrained multi-item inventory systeṁs an implicit approach

This paper examines the N-item deterministic inventory model subject to a single linear constraint. Functional relationships between the Lagrangian multipliers and shifts occurring simultaneously in multiple system parameters are identified and used to establish effective initial bounds on the optimal multiplier, Φ^*, in closed form. A recursive process which rapidly converges to Φ^* is also presented. Finally, a comparative analysis highlighting the efficiency of the proposed process in relation to existing algorithms is exhibited.     

Effect of profound suppression of luteinizing hormone during treatment with gonadotrophin-releasing hormone analogue and purified follicle stimulating hormone upon development of cryopreserved embryos

In response to previously published evidence from monkeys, this study examined the influence of the degree of luteinizing hormone (LH) suppression during the follicular phase of the stimulation cycle, upon cryopreserved embryo survival and development. The LH concentration of the mid-follicular phase was assessed in 250 in-vitro fertilization (IVF) cycles treated with gonadotrophin-releasing hormone analogue (GnRHa) and either purified follicle stimulating hormone (FSH) or human menopausal gonadotrophin (HMG), and was related to the performance of cryopreserved embryos in 351 subsequent embryo transfer cycles. Rates of embryo survival, embryo development rates, implantation rates, and pregnancy rates were examined with respect to the LH concentration recorded in the mid-follicular phase. In contrast to experimental evidence from other primates, there was no significant influence of the follicular phase LH concentration upon any of the parameters examined.     

Mass Transfer and Solute Diffusion in Brined Cucumbers

ABSTRACT: The exchange of malic acid, lactic acid, NaCl, and sugar between cucumber and cover brine was monitored over a course of 16 days for 5 sizes of cucumbers. Experimental results showed that sugar exchange between cucumbers and cover brine was the slowest. In comparison to Ficks diffusion equation, the exponential equation better described the movement of solutes during the brine fermentation of cucumbers. Diffusion coefficient of sugar was estimated to vary from 1.80 × 10–9 to 9.18 × 10–9 m2/s. Solute sorption rate from the exponential model varied from 0.0204 to 0.233 h-1 and decreased with increase in cucumber size and solute molecular weight.     

Crosstalk in 1.3 μm praseodymium fluoride fiber amplifiers

Praseodymium-doped fluoride fiber amplifiers have been demonstrated to provide good gain, output power, and noise performance in the second telecommunications window. This paper presents a study of the crosstalk performance of these amplifiers. A theoretical analysis is presented from which a numerical model is developed and is used to predict the crosstalk performance of a typical amplifier. Experimental results, using two separate signals within the gain band, show good agreement between measurement and theory, indicating that it is unlikely that crosstalk will present a problem in anticipated amplifier applications. From the measured crosstalk, an upper limit is placed on the lower level lifetime, indicating that the population of this level will have a negligible effect amplifier gain. A novel technique for measuring the upper state lifetime in an amplifier, based on pump power dependence of crosstalk, is described and experimental results which are in agreement with fluorescent decay are presented