Testing of turbulent seals for rotordynamic coefficients

A facility has been developed for dynamic testing of straight and convergent tapered seals with the capability of measuring the radial and tangential force components which result from a circular centered orbit. The test apparatus causes the seal journal to execute small-eccentricity centered circular orbits within its clearance circle. Dynamic measurements are made and recorded of the seal displacement-vector components, and of the pressure field. The pressure field is integrated to yield seal tangential and radial reaction-force components. Representative test data are provided and discussed for straight seals

A high-Reynolds-number seal test facility: Facility description and preliminary test data

A facility has been developed for testing the leakage and rotordynamic characteristics of interstage-seal configurations for the HPFTP (High Pressure Fuel Turbopump) of the SSME (Space Shuttle Main Engine). Axial Reynolds numbers on the order of 400,000 are realized in the test facility by using a Dupont freon fluid called Halon (CBrF3). The kinematic viscosity of Halon is of the same order as the liquid hydrogen used in the HPFTP. Initial testing has focused on the current flight configurations (a three-segment, stepped unit) and a convergent-taper candidate

Reading instruction in first-grade classrooms: Do basals control teachers?

This study describes first-grade teachers beliefs and practices about reading instruction. Drawing from interview and observational data, 16 teachers from four districts were placed on a continuum from skills-based to literature-based in relationship to their use of the basal. Only 2 teachers were found to rely solely on the basal, while 3 teachers enhanced the basal with literature, and 4 teachers used only literature in their reading instruction. Six teachers enhanced their basal use with additional skills and 1 teacher relied on skills only in her reading instruction. This diversity\u27 of teaching beliefs and practices was corroborated by questionnaire data from a larger sample of teachers. Next, a framework developed by Belenky, Clinchy, Goldberger, and Tarule (1986) was used to categorize teachers\u27 ways of knowing. The findings showed 1 teacher to be a silent knower, 6 were received knowers, 1 was a subjective knower, 7 were procedural knowers, and 1 was a connected knower. Results challenge Shannon\u27s (1987) hypothesis that basals deskill teachers while supporting Sosniak and Stodolskv\u27s (1993) view that teachers are more autonomous in their use of textbook materials

Particle diffusional layer thickness in a USP dissolution apparatus II: A combined function of particle size and paddle speed

This work was to investigate the effects of particle size and paddle speed on the particle diffuisonal layer thickness h app in a USP dissolution apparatus II. After the determination of the powder dissolution rates of five size fractions of fenofibrate, including <20, 20–32, 32–45, 63–75, and 90–106 µm, the present work shows that the dependence of h app on particle size follows different functions in accordance with the paddle speed. At 50 rpm, the function of h app is best described by a linear plot of $h_{{rm app}} = 9.91sqrt d - 23.31$ ( R 2  = 0.98) throughout the particle diameter, d , from 6.8 to 106 µm. In contrast, at 100 rpm a transitional particle radius, r , of 23.7 µm exists, under which linear relationship h app  = 1.59 r ( R 2  = 0.98) occurs, but above which h app becomes a constant of 43.5 µm. Thus, h app changes not only with particle size, but also with the hydrodynamics under standard USP configurations, which has been overlooked in the past. Further, the effects of particle size and paddle speed on h app were combined using dimensionless analysis. Within certain fluid velocity/particle regime, linear correlation of h app / d with the square-root of Reynolds number $(dvarpi /upsilon )^{1/2}$ , that is, $h_{{rm app}} /d = 1.5207 - 9.25 times 10^{ - 4} (dvarpi /nu )^{1/2}$ ( R 2  = 0.9875), was observed. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:4815–4829, 2008Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61209/1/21345_ftp.pd

Evidence for ACTN3 as a genetic modifier of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is characterized by muscle degeneration and progressive weakness. There is considerable inter-patient variability in disease onset and progression, which can confound the results of clinical trials. Here we show that a common null polymorphism (R577X) in ACTN3 results in significantly reduced muscle strength and a longer 10\u2009m walk test time in young, ambulant patients with DMD; both of which are primary outcome measures in clinical trials. We have developed a double knockout mouse model, which also shows reduced muscle strength, but is protected from stretch-induced eccentric damage with age. This suggests that \u3b1-actinin-3 deficiency reduces muscle performance at baseline, but ameliorates the progression of dystrophic pathology. Mechanistically, we show that \u3b1-actinin-3 deficiency triggers an increase in oxidative muscle metabolism through activation of calcineurin, which likely confers the protective effect. Our studies suggest that ACTN3 R577X genotype is a modifier of clinical phenotype in DMD patients

Physicochemical and physiological mechanisms for the effects of food on drug absorption: The role of lipids and pH

Drugs are absorbed after oral administration as a consequence of a complex array of interactions between the drug, its formulation, and the gastrointestinal (GI) tract. The presence of food within the GI tract impacts significantly on transit profiles, pH, and its solubilization capacity. Consequently, food would be expected to affect the absorption of co‐administered drugs when their physicochemical properties are sensitive to these changes. The physicochemical basis by which ingested food/lipids induce changes in the GI tract and influence drug absorption are reviewed. The process of lipid digestion is briefly reviewed and considered in the context of the absorption of poorly water‐soluble drugs. The effect of food on GI pH is reviewed in terms of location (stomach, upper and lower small intestine) and the temporal relationship between pH and drug absorption. Case studies are presented in which postprandial changes in bioavailability are rationalized in terms of the sensitivity of the physicochemical properties of the administered drug to the altered GI environment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97269/1/1_ftp.pd

Secretome survey of human plexiform neurofibroma derived schwann cells reveals a secreted form of the RARRES1 protein.

To bring insights into neurofibroma biochemistry, a comprehensive secretome analysis was performed on cultured human primary Schwann cells isolated from surgically resected plexiform neurofibroma and from normal nerve tissue. Using a combination of SDS-PAGE and high precision LC-MS/MS, 907 proteins were confidently identified in the conditioned media of Schwann cell cultures combined. Label free proteome profiling revealed consistent release of high levels of 22 proteins by the four biological replicates of NF1 Schwann cell cultures relative to the two normal Schwann cell cultures. Inversely, 9 proteins displayed decreased levels in the conditioned media of NF1 relative to normal Schwann cells. The proteins with increased levels included proteins involved in cell growth, angiogenesis and complement pathway while proteins with decreased levels included those involved in cell adhesion, plasminogen pathway and extracellular matrix remodeling. Retinoic acid receptor responder protein-1 (RARRES1), previously described as an integral membrane tumor suppressor, was found exclusively secreted by NF1 Schwann cells but not by normal Schwann cells. All-trans retinoic acid modulated secretion of RARRES1 in a dose dependent manner. This study shows altered secretion of key proteins in NF1 derived Schwann cells. The potential implication of these proteins in neurofibroma biology is discussed

Biowaiver monographs for immediate release solid oral dosage forms: prednisolone.

Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing prednisolone are reviewed. Data on its solubility, oral absorption, and permeability are not totally conclusive, but strongly suggest a BCS Class 1 classification. Prednisolone's therapeutic indications and therapeutic index, pharmacokinetics, and the possibility of excipient interactions were also taken into consideration. Available evidence indicates that a biowaiver for IR solid oral dosage forms formulated with the excipients tabulated in this article would be unlikely to expose patients to undue risks

Effect of Intragastric pH on the Absorption of Oral Zinc Acetate and Zinc Oxide in Young Healthy Volunteers

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142255/1/jpen0393.pd

So What\u27s New in the New Basals? A Focus on First Grade

The authors examine the first grade materials in five new basal programs submitted for the 1993 Texas state adoption. These series are compared with program materials currently in use in the state (Copyright 1986/1987). The analysis focuses on features of the pupil texts(e.g., total number of words, number of unique words, readability levels, literary quality) and features of the teachers\u27 editions (e.g., program design, organization, tone). Results of the analysis indicate substantial changes in the more recent series.The findings are interpreted in terms of historical trends as well as recent developments in the literature-based and whole language movements.Implications for future research are identified that relate to the study of the implementation and effects of these new programs