298 research outputs found

    Thermally stable deployable structure

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    A deployable structure which meets stringent thermal and strength requirements in a space environment was developed. A mast with a very low coefficient of thermal expansion (CTE) was required to limit the movement from thermal distortion over the temperature range of -200 C to 80 C to .064 cm (.025 in). In addition, a high bending strength over the temperature range and weight less than 18.1 kg (40 lbs) was needed. To meet all of the requirements, a composite, near-zero CTE structure was developed. The measured average CTE over the temperature range for the mast was .70 x .000001/C (.38 x .000001/F). The design also has the advantage of being adjustable to attain other specific CTE if desired

    Expression of somatostatin receptors 3, 4, and 5 in mouse kidney proximal tubules

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    Expression of somatostatin receptors 3, 4, and 5 in mouse kidney proximal tubules.BackgroundSystemic infusion of somatostatin (SRIF) induces many physiological changes in human and rodent kidneys, including alterations in glomerular filtration, solute transport, and water clearance. Although somatostatin can bind to five different G-protein coupled receptors (SSTRs), only SSTR1 and SSTR2A proteins have been described convincingly in rat and/or human kidneys. Both are expressed primarily in collecting ducts, despite clear evidence that somatostatin also can bind to proximal tubules. Our aim was to characterize the expression of somatostatin receptors three to five in adult mouse kidneys.MethodsReverse transcriptase-polymerase chain reaction (RT-PCR) was performed followed by Southern blotting on mouse kidney RNA for SSTR3, SSTR4, and SSTR5. Immunohistochemistry and dual-labeling immunofluorescence also were performed to localize the receptors in the kidney.ResultsMessenger RNA was detected for somatostatin receptors 3 to 5 in the mouse kidney by RT-PCR, with confirmation by Southern blotting. By immunohistochemistry and dual-labeling immunofluorescence, the proteins for all three receptors were abundantly expressed, but exclusively localized to the proximal tubules. SSTR3 was present in intracellular granules, while SSTR4 and SSTR5 were expressed on the lumenal membranes of the tubules.ConclusionsExpression of SSTR3, SSTR4, and SSTR5 in mouse proximal tubules complements the expression of SSTR1 and SSTR2 in collecting ducts as seen in other species. Taken together, the kidney is one of few organs expressing all five somatostatin receptors outside of the nervous system and pancreas

    Bearer Negotiable Instruments: Addressing a Financial Intelligence Gap and Identifying Criminogenic Weaknesses

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    Bearer Negotiable Instruments (BNI) are a long-standing category of financial instruments used to transfer large amounts of money in ways that may not be subject to regulation, reporting, tracking, review, or oversight. There is limited information available on BNIs, and no evidence that any studies have been undertaken on BNIs alone, much less reported. Increasingly, BNIs are being used for illegal purposes including money laundering. This study gathers information about their characteristics, nature, purpose, legal status, and numbers. It also focuses on the crime risks associated with BNIs, the crime opportunities they facilitate, and the criminal weaknesses in the financial instruments themselves. Data and knowledge are obtained to provide a sound basis for further study and analysis, and to make policy recommendations that reflect practical, corrective, and preventative measures to reduce future crime using BNIs

    Role of fibroblast growth factor receptors 1 and 2 in the ureteric bud

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    AbstractFibroblast growth receptors (FGFRs) consist of four signaling family members. Mice with deletions of fgfr1 or fgfr2 are embryonic lethal prior to the onset of kidney development. To determine roles of FGFR1 and FGFR2 in the ureteric bud, we used a conditional targeting approach. First, we generated transgenic mice using the Hoxb7 promoter to drive cre recombinase and green fluorescent protein expression throughout ureteric bud tissue. We crossed Hoxb7creEGFP mice with mice carrying lox-p sites flanking critical regions of fgfr1 and/or fgfr2. Absence of fgfr1 from the ureteric bud (fgfr1UB−/−) results in no apparent renal abnormalities. In contrast, fgfr2UB−/− mice have very aberrant ureteric bud branching, thin ureteric bud stalks, and fewer ureteric bud tips. Fgfr2UB−/− ureteric bud tips also demonstrate inappropriate regions of apoptosis and reduced proliferation. The nephrogenic mesenchymal lineage in fgfr2UB−/− mice develops normal-appearing glomeruli and tubules, and only slightly fewer nephrons than controls. In contrast, fgfr2UB−/− kidneys have abnormally thickened subcapsular cortical stromal mesenchyme. Ultimately, fgfr2UB−/− adult kidneys are small and abnormally shaped or are hydronephrotic. Finally, there are no additional abnormalities in the fgfr1/2UB−/− kidneys versus the fgfr2UB−/− kidneys. In conclusion, FGFR2, but not FGFR1, appears crucial for ureteric bud branching morphogenesis and stromal mesenchyme patterning

    Displacements analysis of self-excited vibrations in turning

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    The actual research deals with determining by a new protocol the necessary parameters considering a three-dimensional model to simulate in a realistic way the turning process on machine tool. This paper is dedicated to the experimental displacements analysis of the block tool / block workpiece with self-excited vibrations. In connexion with turning process, the self-excited vibrations domain is obtained starting from spectra of two accelerometers. The existence of a displacements plane attached to the tool edge point is revealed. This plane proves to be inclined compared to the machines tool axes. We establish that the tool tip point describes an ellipse. This ellipse is very small and can be considered as a small straight line segment for the stable cutting process (without vibrations). In unstable mode (with vibrations) the ellipse of displacements is really more visible. A difference in phase occurs between the tool tip displacements on the radial direction and on the cutting one. The feed motion direction and the cutting one are almost in phase. The values of the long and small ellipse axes (and their ratio) shows that these sizes are increasing with the feed rate value. The axis that goes through the stiffness center and the tool tip represents the maximum stiffness direction. The maximum (resp. minimum) stiffness axis of the tool is perpendicular to the large (resp. small) ellipse displacements axis. FFT analysis of the accelerometers signals allows to reach several important parameters and establish coherent correlations between tool tip displacements and the static - elastic characteristics of the machine tool components tested

    Efavirenz directly modulates the oestrogen receptor and induces breast cancer cell growth

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    Efavirenz-based HIV therapy is associated with breast hypertrophy and gynaecomastia. Here, we tested the hypothesis that efavirenz induces gynaecomastia through direct binding and modulation of the oestrogen receptor (ER).To determine the effect of efavirenz on growth, the oestrogen-dependent, ER-positive breast cancer cell lines MCF-7, T47D and ZR-75-1 were treated with efavirenz under oestrogen-free conditions in the presence or absence of the anti-oestrogen ICI 182,780. Cells treated with 17β-oestradiol in the absence or presence of ICI 182,780 served as positive and negative controls, respectively. Cellular growth was assayed using the crystal violet staining method and an in vitro receptor binding assay was used to measure the ER binding affinity of efavirenz.Efavirenz induced growth in MCF-7 cells with an estimated effective concentration for half-maximal growth (EC 50 ) of 15.7 μM. This growth was reversed by ICI 182,780. Further, efavirenz binds directly to the ER [inhibitory concentration for half maximal binding (IC 50 ) of ∼52 μM] at a roughly 1000-fold higher concentration than observed with 17β-oestradiol.Our data suggest that efavirenz-induced gynaecomastia may be caused, at least in part, by drug-induced ER activation in breast tissues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79275/1/j.1468-1293.2010.00831.x.pd

    Evaluation of Social Media Use by Emergency Medicine Residents and Faculty

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    Introduction Clinicians and residency programs are increasing their use of social media (SM) websites for educational and promotional uses, yet little is known about the use of these sites by residents and faculty. The objective of the study is to assess patterns of SM use for personal and professional purposes among emergency medicine (EM) residents and faculty. Methods In this multi-site study, an 18-question survey was sent by e-mail to the residents and faculty in 14 EM programs and to the Council of Emergency Medicine Residency Directors (CORD) listserv via the online tool SurveyMonkey™. We compiled descriptive statistics, including assessment with the chi-square test or Fisher’s exact test. StatsDirect software (v 2.8.0, StatsDirect, Cheshire, UK) was used for all analyses. Results We received 1,314 responses: 63% of respondents were male, 40% were <30 years of age, 39% were between the ages 31 and 40, and 21% were older than 40. The study group consisted of 772 residents and 542 faculty members (15% were program directors, 21% were assistant or associate PDs, 45% were core faculty, and 19% held other faculty positions. Forty-four percent of respondents completed residency more than 10 years ago. Residents used SM markedly more than faculty for social interactions with family and friends (83% vs 65% [p<0.0001]), entertainment (61% vs 47% [p<0.0001]), and videos (42% vs 23% [p=0.0006]). Residents used Facebook™ and YouTube™ more often than faculty (86% vs 67% [p<0.001]; 53% vs 46% [p=0.01]), whereas residents used Twitter™ (19% vs 26% [p=0.005]) and LinkedIn™ (15% vs 32% [p<0.0001]) less than faculty. Overall, residents used SM sites more than faculty, notably in daily use (30% vs 24% [p<0.001]). For professional use, residents were most interested in its use for open positions/hiring (30% vs 18% [p<0.0001]) and videos (33% vs 26% [p=0.005]) and less interested than faculty with award postings (22% vs 33% [p<0.0001]) or publications (30% vs 38% [p=0.0007]). Conclusion EM residents and faculty have different patterns and interests in the personal and professional uses of social media. Awareness of these utilization patterns could benefit future educational endeavors

    Social media guidelines and best practices - Recommendations from the council of residency directors (cord) social media taskforce

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    Social media has become a staple of everyday life among over one billion people worldwide. A social networking presence has become a hallmark of vibrant and transparent communications. It has quickly become the preferred method of communication and information sharing. It offers the ability for various entities, especially residency programs, to create an attractive internet presence and “brand� the program. Social media, while having significant potential for communication and knowledge transfer, carries with it legal, ethical, personal, and professional risks. Implementation of a social networking presence must be deliberate, transparent, and optimize potential benefits while minimizing risks. This is especially true with residency programs. The power of social media as a communication, education, and recruiting tool is undeniable. Yet the pitfalls of misuse can be disastrous, including violations in patient confidentiality, violations of privacy, and recruiting misconduct. These guidelines were developed to provide emergency medicine residency programs leadership with guidance and best practices in the appropriate use and regulation of social media, but are applicable to all residency programs that wish to establish a social media presence

    Sources of nonlinearities, chatter generation and suppression in metal cutting

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    The mechanics of chip formation has been revisited in order to understand functional relationships between the process and the technological parameters. This has led to the necessity of considering the chip-formation process as highly nonlinear, with complex interrelations between its dynamics and thermodynamics. In this paper a critical review of the state of the art of modelling and the experimental investigations is outlined with a view to how the nonlinear dynamics perception can help to capture the major phenomena causing instabilities (chatter) in machining operations. The paper is concluded with a case study, where stability of a milling process is investigated in detail, using an analytical model which results in an explicit relation for the stability limit. The model is very practical for the generation of the stability lobe diagrams, which is time consuming when using numerical methods. The extension of the model to the stability analysis of variable pitch cutting tools is also given. The application and verification of the method are demonstrated by several examples
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