Determination of intraparticulate mass transfer coefficients via permeation measurements: theory and experimental validation

A mathematical model of mass transfer through a heterogeneous, multiphase barrier has been developed where the dispersed phase is capable of uptake of the diffusant according to a linear relationship. The model was used to describe the penetration of drugs through dispersions of permeable globules in media of known diffusional properties. Water-in-oil-in-water (W/O/W) multiple emulsions have been studied by this method. When used to analyze data obtained with a simple diffusion cell, the model allows the calculation of the mass transfer coefficient which characterizes the diffusional mass transfer across oil-water interfaces within the emulsions. The mass transfer coefficient is directly related to the drug release rate from the internal phases of multiple emulsions. Those cases where instantaneous equilibria are established or where impermeable globules are present can be treated as special limiting cases. Differential equations which express diffusant concentrations as functions of time, space, and dispersion system parameters have been solved by Laplace transformation without recourse to numerical methods. The values of the mass transfer coefficient are shown to reflect the physical characteristics of multiple emulsion systems.     

Imaging of follicular dendritic cell tumours of the liver

Follicular dendritic cell tumour of the liver is a recently recognized entity. To date, only two cases have been described, both in the pathology literature. Histologically, it resembles an inflammatory pseudotumour and immunohistochemical and ultrastructural studies are required for its diagnosis. The ultrasound, computed tomography and angiographic features of two cases of follicular dendritic cell tumour of the liver are described in detail. One of the patients had multiple recurrences of this tumour. The imaging features are very similar to those of hepatocellular carcinoma. As follicular dendritic cell tumour is considered to be of low-grade malignant potential, in contrast to the dismal prognosis for hepatocellular carcinoma, it is important to be able to accurately distinguish between the two types of tumour prior to initiating definitive therapy.     

Hip impact velocities and body configurations for voluntary falls from standing height

OBJECTIVE: To determine prevalence of various pheno- and genotypes of Serpulina sp in young pigs in relation to diarrhea and feed medication in Swedish pig-rearing herds. DESIGN: Isolation of spirochetes. Phenotypical and genotypical classification. SAMPLE POPULATION: Young pigs (n = 358) in 19 pigrearing herds. PROCEDURE: Serpulina isolates were classified according to a biochemical scheme based on hemolysis, indole production, hippurate hydrolysis, and alpha-galactosidase, alpha-glucosidase, and beta-glucosidase activities. The 16S rRNA sequences for 10 of the field strains and 2 type strains of Serpulina spp were aligned and compared. Minimum inhibitory concentrations of olaquindox for 9 of the strains were determined. RESULTS: Weakly beta-hemolytic intestinal spirochetes (WBHIS) were isolated from 17 of the herds and 65% of the samples. More than 1 phenotype of WBHIS was found in 12 of the 19 herds. S hyodysenteriae was not isolated in any of the herds. Hippurate-positive WBHIS were isolated in 6 of 7 herds affected by diarrhea, but in only 1 of 8 herds without diarrhea. Hippurate-positive strains were closely related to the pathogenic strain P43 if judged from sequence comparisons. Strains with the same biochemical profile isolated within a herd had identical sequences, but when isolated from different herds, sequence differences were observed. The prevalence of WBHIS was reduced in herds medicated with olaquindox. Investigated field strains had minimum inhibitory concentration values < or = 1 microgram/ml for olaquindox. CONCLUSION: The presence of WBHIS, with the ability to hydrolyze hippurate, was related to diarrhea in pig herds. CLINICAL RELEVANCE: Potentially pathogenic WBHIS can be distinguished from nonpathogenic strains by the hippurate hydrolysis test.     

Airborne scatterometers: investigating ocean backscatter under low and high-wind conditions

Attempting to understand and predict weather on a local and global basis has challenged both the scientific and engineering communities. One key parameter in understanding the weather is the ocean surface wind vector because of its role in the energy exchange at the air-sea surface. scatterometers, radars that measure the reflectivity of a target offer a tool with which to remotely monitor these winds from tower-, aircraft-, and satellite-based platforms. This paper introduces three current airborne scatterometer systems, and presents data collected by these instruments under low-, moderate-, and high-wind conditions. The paper focuses on airborne scatterometers because of their ability to resolve submesoscale variations in wind fields. Discrepancies between existing theory and the observations are noted and the concerns in measuring low-wind speeds discussed. Finally, the application of using this technology for estimating the surface-wind vector during a hurricane is demonstrated     

The inhibition of DMBA-induced carcinogenesis by neoxanthin in hamster buccal pouch

Neoxanthin, a major carotenoid pigment of spinach, is found in the Chloroplast membrane and has an unknown function in plants. Neoxanthin inhibited the production of superoxide anions in an artificial xanthine and xanthine oxidase system and depressed DNA synthesis in methylcholanthrene (MCA)-initiated C3H10T1/2 fibroblasts. in two-stage carcinogenesis experiments, neoxanthin at 0.2 micrograms/0.2 ml inhibited the formation of tumors that were induced sequentially by 7,12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) in the buccal pouch of Syrian Golden hamsters. To assess the ongoing process of carcinogenesis, the activity of ornithine decarboxylase (ODC), required for cell proliferation, was analyzed. Neoxanthin inhibited the activity of ODC when animals were treated with neoxanthin one hour before the application of TPA in two-stage carcinogenesis. However, neoxanthin did not inhibit ODC activity when animals were treated with neoxanthin one hour before the application of DMBA in two-stage carcinogenesis, and there was no subsequent tumor formation. In a short-term anti-initiation experiment, neoxanthin inhibited the covalent binding of isotope-labeled DMBA to DNA by 53%. These results indicate that neoxanthin inhibits the initiation stage and the promotion stage in two-stage carcinogenesis. This suggests that neoxanthin may act as a potential chemopreventive agent.     

Treatment with alendronate prevents fractures in women at highest risk: results from the Fracture Intervention Trial

BACKGROUND: The efficacy of antiresorptive therapy in preventing fractures in women at highest fracture risk, such as very elderly women or those with severe osteoporosis, is uncertain. PARTICIPANTS AND METHODS: Using data from a double-blind, randomized, placebo-controlled clinical trial that enrolled 2027 postmenopausal women aged 55 to 81 years with low femoral neck bone mineral density (BMD) and existing vertebral fractures, we examined the consistency of the effect of treatment with alendronate sodium in preventing fractures within a priori-specified risk subgroups defined at baseline by age, bone density, number of preexisting vertebral fractures, and history of postmenopausal fracture. The women were randomized to oral administration of alendronate or placebo and followed up for an average of 2.9 years. The initial dose of alendronate sodium was 5 mg/d; the dosage was increased from 5 to 10 mg/d at 24 months. New vertebral fractures, the primary end point of this arm of the trial, were defined by morphometry as a decrease of 20% and at least 4 mm in any vertebral height between baseline and a follow-up radiograph at 36 months. Incident clinical fractures, the secondary end point, included nonspine and clinical (symptomatic) vertebral fractures. All clinical fractures were confirmed with x-ray film reports or, in the case of clinical vertebral fractures, x-ray films. RESULTS: Overall, there was a 47% significant reduction in risk of new vertebral fractures in the alendronate group compared with the placebo group. The reduction in risk of new vertebral fracture was consistent across fracture risk categories including age (relative risk [RR], 0.49 in women < 75 years compared with 0.62 in those > or = 75 years), BMD (RR, 0.54 in women with a femoral neck BMD < 0.59 g/cm2 [median] compared with 0.53 in those with a BMD > or = 0.59 g/cm2), and number of preexisting vertebral fractures (RR, 0.58 in women with 1 vertebral fracture compared with 0.52 in those with > or = 2). The overall significant 28% reduction in risk of incident clinical fractures in the alendronate group compared with the placebo group was also observed within these subgroups. Compared with the number of lower-risk women, a similar or smaller number of high-risk women needed to be treated to prevent 1 fracture. For example, 8 women aged 75 years or older compared with 9 women younger than 75 years, or 4 women with 2 or more existing vertebral fractures compared with 16 women with 1 existing vertebral fracture, needed to be treated with alendronate for 5 years to prevent 1 new vertebral fracture. CONCLUSIONS: Alendronate effectively reduces fracture risk in postmenopausal women with vertebral fractures and low BMD, including those women at highest risk because of advanced age or severe osteoporosis. Since the risk reductions observed with alendronate treatment were consistent within fracture risk categories, more fractures were prevented by treating women at highest risk.     

Flexible speech translation systems

Speech translation research has made significant progress over the years with many high-visibility efforts showing that translation of spontaneously spoken speech from and to diverse languages is possible and applicable in a variety of domains. As language and domains continue to expand, practical concerns such as portability and reconfigurability of speech come into play: system maintenance becomes a key issue and data is never sufficient to cover the changing domains over varying languages. In this paper, we discuss strategies to overcome the limits of today's speech translation systems. In the first part, we describe our layered system architecture that allows for easy component integration, resource sharing across components, comparison of alternative approaches, and the migration toward hybrid desktop/PDA or stand-alone PDA systems. In the second part, we show how flexibility and reconfigurability is implemented by more radically relying on learning approaches and use our English-Thai two-way speech translation system as a concrete example.     

Ampacities of power cables wound on reels

This paper presents a mathematical model that is capable of calculating the ampacity of a wide variety of power cable designs consisting of an arbitrary number of layers on a cable reel. The model considers round cables with copper conductors. The validity and accuracy of the ampacity model were verified by comparing the predicted temperature distribution within the reel with measured temperatures collected during an extensive testing program conducted at the US Bureau of Mines (USBM). The mathematical model predicted a temperature distribution within the cable layers that was very close to the measured variation in temperature. The value of the program is illustrated by calculating ampacities for several copper conductor sizes     

Therapeutic evaluation of compounds in the SCID-RA papillomavirus model

A previous study by Kreider (Kreider et al., 1979) indicated that rabbit skin, which had been transplanted to immunodeficient nude mice, could be successfully infected with cottontail rabbit papillomavirus (CRPV). We have extended this observation in developing a rodent model for evaluation of compounds for activity against the papillomaviruses. In this model (called the SCID-Ra model), rabbit ear skin is transplanted to the dorsum of SCID mice and allowed to heal for 3 weeks. Infection with CRPV by scarification leads to the growth of warty lesions within 2 3 weeks in >95% of the animals. Topical and/or systemic therapy can be initiated at various times post infection (PI). Weekly lesion scores are recorded and compounds are evaluated for their ability to suppress wart growth when compared to untreated control mice. Ribavirin, which has had a suppressive effect both in the clinic for the treatment of respiratory papillomatosis and on the growth of warts in the rabbit back model, was evaluated and showed significant anti-proliferative activity with oral dosing. Both antiviral and antiproliferative compounds including podophyllin and 5-fluorouracil, which have been used clinically for the treatment of human papillomavirus (HPV) infections, were evaluated in this model. The anti-mitotic compound, Navelbine (vinorelbine tartrate), which is used for the treatment of non-small cell lung carcinoma was evaluated in this system and showed significant inhibition of wart growth with somewhat less topical cytotoxicity when compared to podophyllotoxin.