Group B streptococcal vulvovaginitis

OBJECTIVE: To explore the relationship between Heart Meridian (HM) and cardiac function. METHODS: Forty-eight rabbits with acute myocardial ischemia resulting from intravenous pituitrin injection was conducted. Electroacupunture(EA) on the HM and the Lung meridian, 3 points for each, was applied and their change of arterial pressure was observed. RESULTS: The distinct difference existed in the improvement of arterial pressure on the HM and Lung Meridian with EA. The regulatory action of EA in HM on the cardiac function was significantly better than that of EA in Lung Meridian. CONCLUSION: HM was closely related to the cardiac function.     

Comparison of steady-state diffusion and transit time ultrasonic measurements of umbilical blood flow in the chronic fetal sheep preparation

OBJECTIVE: Our purpose was to measure umbilical blood flow continuously by use of a transit time ultrasonic flow transducer and to compare the blood flow measurements with the steady-state diffusion method in the chronic fetal sheep preparation. STUDY DESIGN: We compared umbilical blood flow measurements calculated by the steady-state diffusion method with ethanol as the diffusing substance and with the transit time ultrasonic flow transducer placed on the common umbilical artery in five chronically prepared fetal sheep. RESULTS: There was no statistical difference between measurements of umbilical blood flow measured by the flow transducer versus the steady-state diffusion method, 600 +/- 22 versus 664 +/- 56 ml per minute (mean +/- SEM) (p = 0.23). The mean coefficient of variation within each study was 13.6% for the steady-state diffusion method versus 4.1% for the transit time flow transducer. Umbilical blood flow variance was significantly lower as measured by the flow transducer compared with the diffusion method (p < 0.0001). There were no differences in umbilical blood flow per kilogram or fetal oxygen uptake between the two methods. CONCLUSION: We conclude that umbilical blood flow can be measured continuously under steady-state conditions by use of a transit time flow transducer. Because of the lower variability in the flow transducer-obtained measurements, we speculate that the flow transducer may differentiate alterations in umbilical blood flow with greater precision in chronic preparations. This may be advantageous for measuring absolute changes in fetal substrate uptake, especially under non-steady-state conditions.     

Synthesis and characterization of melt-polymerizable aminophthalocyanine monomers

The strategy, synthesis, and characterization of a soluble amine-functionalized phthalocyanine monomer and two examples of its polymerization into optically transparent glasses are reported. A simple, fast, and versatile method for incorporating metal ions into the metal-free phthalocyanine is demonstrated. Measurements of the nonlinear optical properties associated with a lead-substituted phthalocyanine/urethane copolymer are also reported. © 1995 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Flow injection analysis estimation of diffusion coefficients of pauci- and polydisperse polymers such as polystyrene sulfonates

Flow injection analysis, often used for determination of diffusion coefficients of nonpolymeric substances, has now been applied to the characterization of pauci- and polydisperse polymers in solution. A relative method was found useful for obtaining moderate quality evaluations of diffusion coefficients and related parameters of polymers. The width at half-height W_1/2 of the trace peak is found to be proportional to the number average molecular weight M?_n of pauci- and polydisperse polymers, allowing estimation of M?_r and diffusion coefficients. For sodium polystyrene sulfonates at substantially infinite dilution in 1.0 g L^?1 Na₂SO₄, a linear relation has been observed between the logarithms of the molecular weight M?_n and the mean diffusion coefficient D in the M?_n range of 1000–90,000 g mol^?1 or the D range of 30 × 10^?7 to 2 × 10^?7 cm² s^?1.     

The effects of light and heat on the rubber content and impact strength of acrylonitrile-butadiene-styrene

DSC analysis of acrylonitrile-butadiene-styrene (ABS) samples either weathered outdoors for up to 10 years or aged at 71°C has shown that these plastics deteriorate most readily through the polybutadiene (BD) component. Oxidation of the BD in ABS leads to an increasing and broadening T_gas well as a decrease in ΔC_p at T_g. The latter quantity can be used to quantitatively assay the amount of unoxidized rubber in a photo- or thermal-oxidized sample. The loss of impact strength of these resins with chemical aging can be correlated with the oxidation of the polybutadiene phase. Studies of rubber content as a function of sample thickness have revealed that an embrittled layer containing oxidized BD develops at the surface of an aged, 100 mil. ABS plaque (natural) and grows to a thickness of about 10 mils after 3 years exposure to sunlight. ABS containing carbon black is effectively screened from this photo induced degradation and consequently has much better retention of its initial impact strength values. In addition, carbon black was observed to retard thermal oxidation in some ABS samples. Lastly, it appears possible to do accelerated aging studies at elevated temperatures to evaluate the relative stabilities of various ABS formulations.     

A three-dimensional approach to multistream migration modelling: local-level flows in Hereford and Worcester

Using data for the English county of Hereford and Worcester, the author presents a method for the analysis of migration at the local level "which does not disaggregate migrant flows by distance criteria alone, but incorporates measures relating to the nature of the origins and of the destinations." The author suggests that "in comparison with a standard single-stream regression model this method improves the fit substantially, and the variability in the resulting parameter estimates for each of the eight streams supports the need for identification of distinct migrant streams. In particular, flows over short distances between wards with high population densities are estimated more effectively."     

A review and analysis of current computer-aided fixture design approaches

A key characteristic of the modern market place is the consumer demand for variety. To respond effectively to this demand, manufacturers need to ensure that their manufacturing practices are sufficiently flexible to allow them to achieve rapid product development. Fixturing, which involves using fixtures to secure workpieces during machining so that they can be transformed into parts that meet required design specifications, is a significant contributing factor towards achieving manufacturing flexibility. To enable flexible fixturing, considerable levels of research effort have been devoted to supporting the process of fixture design through the development of computer-aided fixture design (CAFD) tools and approaches. This paper contains a review of these research efforts. Over seventy-five CAFD tools and approaches are reviewed in terms of the fixture design phases they support and the underlying technology upon which they are based. The primary conclusion of the review is that while significant advances have been made in supporting fixture design, there are primarily two research issues that require further effort. The first of these is that current CAFD research is segmented in nature and there remains a need to provide more cohesive fixture design support. Secondly, a greater focus is required on supporting the detailed design of a fixture's physical structure.     

Safe fabrication of sharp gold tips for light emission in scanning tunnelling microscopy

Gold is the optimal tip metal for light emission in scanning tunnelling microscopy (LESTM) under ambient conditions. Sharp Au-tips of 10 nm radius were produced reliably using a safe, two-step etching method in 20% (w/w) CaCl₂ solution. Previous CaCl₂-based methods have tended to produce blunter tips, while other etching techniques that do produce sharp Au-tips, do so with the use of toxic or hazardous electrolytes. The tips are characterised using scanning electron microscopy and their efficacy in LESTM is evidenced by high-resolution, simultaneous topographic and photon mapping of Au(1 1 1)- and polycrystalline Au-surfaces. Spectra of the optical emission exhibit only one or two peaks with etched tips in contrast to the more complex spectra typical of cut tips; this feature, together with the highly symmetric geometry of the tips, facilitates a definitive analysis of the light emission process.