Thermal performance of two heat exchangers for thermoelectric generators

Thermal performance of heat exchanger is important for potential application in integrated solar cell/module and thermoelectric generator (TEG) system. Usually, thermal performance of a heat exchanger for TEGs is analysed by using a 1D heat conduction theory which ignores the detailed phenomena associated with thermo-hydraulics. In this paper, thermal and mass transports in two different exchangers are simulated by means of a steady-state, 3D turbulent flow k -e model with a heat conduction module under various flow rates. In order to simulate an actual working situation of the heat exchangers, hot block with an electric heater is included in the model. TEG model is simplified by using a 1D heat conduction theory, so its thermal performance is equivalent to a real TEG. Natural convection effect on the outside surfaces of the computational model is considered. Computational models and methods used are validated under transient thermal and electrical experimental conditions of a TEG. It is turned out that the two heat exchangers designed have a better thermal performance compared with an existing heat exchanger for TEGs, and more importantly, the fin heat exchanger is more compact and has nearly half temperature rise compared with the tube heat exchanger

Changing the Surgical Residency: A Mixed-Methods Study of Residents’ and Faculty Experiences One Year After Implementation

Objective: To evaluate a reformed surgical residency curriculum aimed at addressing emerging practice models, enhancing residents’ educational experience, and improving the quality/continuity of patient care by reducing the service size and enhancing attending-resident interactions. Methods: A mixed-methods study of the surgical training program following curriculum reform including: 1) focus group and individual qualitative interviews with residents, attendings, nurses, and advanced practice providers to explore stakeholder perspectives on curriculum reform, 2) time study of surgical resident activities, and 3) quantitative assessment of surgical case logs. Results: Qualitative interviews demonstrated disparate knowledge and attitudes regarding the goals of the curriculum with emergence of several themes during transcript analysis including: Goals of the Change, Learning and Educational Value, Communication, Teamwork, Service, and Quality of Life. Both positive aspects of curriculum reform (e.g., improved focus on resident education and balance between educational and service activities, communication, and opportunity for direct feedback and observation) and negative ones (e.g., lack of role clarity, insufficient workforce) were identified. Despite limitations, the time study revealed variability in resident activities by post-graduate year with more time spent on indirect patient care activities in the early years and more time in the OR and one-on-one with attendings later. Quantitative analysis of surgical case logs, previously published, showed no significant decrease in number of cases for residents by either training level or role. Conclusions: This single-institution mixed methods study suggests that a reformed surgical residency curriculum improved residents’ educational experiences and the balance between educational and service activities without affecting operative volume. Multiple modalities of assessment are essential to identify the various positive and negative aspects of an educational intervention

Effects of genuine dimension-six Higgs operators

We systematically discuss the consequences of genuine dimension-six Higgs operators. These operators are not subject to stringent constraints from electroweak precision data. However, they can modify the couplings of the Higgs boson to electroweak gauge bosons and, in particular, the Higgs self-interactions. We study the sensitivity to which those couplings can be probed at future \ee linear colliders in the sub-TeV and in the multi-TeV range. We find that for $\sqrt s=500$ GeV with a luminosity of 1 ab$^{-1}$ the anomalous $WWH$ and $ZZH$ couplings may be probed to about the 0.01 level, and the anomalous $HHH$ coupling to about the 0.1 level.Comment: 21 pages, 17 figures; typos corrected and references adde

Chemistry Pharmacology And Behavioral Studies Identify Chiral Cyclopropanes As Selective α4β2-Nicotinic Acetylcholine Receptor Partial Agonists Exhibiting An Antidepressant Profile. Part II

A 3-pyridyl ether scaffold bearing a cyclopropane-containing side chain was recently identified in our efforts to create novel antidepressants that act as partial agonists at α4β2-nicotinic acetylcholine receptors. In this study, a systematic structure-activity relationship investigation was carried out on both the azetidine moiety present in compound 3 and its right-hand side chain, thereby discovering a variety of novel nicotinic ligands that retain bioactivity and feature improved chemical stability. The most promising compounds, 24, 26, and 30, demonstrated comparable or enhanced pharmacological profiles compared to the parent compound 4, and the N-methylpyrrolidine analogue 26 also exhibited robust antidepressant-like efficacy in the mouse forced swim test. The favorable ADMET profile and chemical stability of 26 further indicate this compound to be a promising lead as a drug candidate warranting further advancement down the drug discovery pipeline. © 2013 American Chemical Society

Age-related decline in protein synthesis in the rat parotid gland

This study was undertaken to determine whether protein synthesis declines with age in parorid salivary glands. We have examined the level of incorporation of [3H]-leucine into protein and the metabolism of [U-14C]-D-glucose in 2-, 12-, 18-, 24- and 30-month-old rats. The rate of incorporation of [3H]-leucine into perchloric acid insoluble protein by gland slices decreases progressively with age from 138.43+/-5.43 nmole/mg DNA/h at 2 months to 109.77+/-6.88, 97+/-4.68, 71.62+/-4.13 and 58.08+/-5.61 nmole/mg DNA/h at 12, 18, 24 and 30 months, respectively. The amount of radioactivity in the perchloric acid soluble fraction remains relatively stable at all ages. The ability of gland slices to oxidize [U-14C]-D-glucose to 14CO2 and to incorporate radioactivity into the total lipid does not change with age, whereas the incorporation of radioactivity into protein decreases significantly from 45.06+/-3.55 at 2 months to 21.75+/-1.30 nmoles glucuse/mg DNA/h at 24 months. Histologically, no significant change is detected in the proportion of secretory cells to ductal cells in the different age groups. In radioautographs of the glands incubated with [3H]-leucine, the distribution of cells with grains is similar in all age groups. Lipid droplets occur at the periphery of the lobules and a large number of lipofuscin granules are present in secretory acinar cells of 12-month-old and older rats when viewed in the electron microscope. However, the structural integrity in the cellular organelles is maintained in the acinar cells of all age groups. These results indicate that the ability of parotid gland cells to synthesize protein decreases with age. The decrease reflects specific changes in protein synthesis and not an overall decline in cellular metabolism or a decrease in the number of cells which incorporate leucine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23360/1/0000304.pd

Epistemic Beliefs: Relationship to Future Expectancies and Quality of Life in Cancer Patients.

CONTEXT: Expectations about the future (future expectancies) are important determinants of psychological well-being among cancer patients, but the strategies patients use to maintain positive and cope with negative expectancies are incompletely understood. OBJECTIVES: To obtain preliminary evidence on the potential role of one strategy for managing future expectancies: the adoption of epistemic beliefs in fundamental limits to medical knowledge. METHODS: A sample of 1307 primarily advanced-stage cancer patients participating in a genomic tumor testing study in community oncology practices completed measures of epistemic beliefs, positive future expectancies, and mental and physical health-related quality of life (HRQOL). Descriptive and linear regression analyses were conducted to assess the relationships between these factors and test two hypotheses: 1) epistemic beliefs affirming fundamental limits to medical knowledge ( fallibilistic epistemic beliefs ) are associated with positive future expectancies and mental HRQOL, and 2) positive future expectancies mediate this association. RESULTS: Participants reported relatively high beliefs in limits to medical knowledge (M = 2.94, s.d.=.67) and positive future expectancies (M = 3.01, s.d.=.62) (range 0-4), and relatively low mental and physical HRQOL. Consistent with hypotheses, fallibilistic epistemic beliefs were associated with positive future expectancies (b = 0.11, SE=.03, P\u3c 0.001) and greater mental HRQOL (b = 0.99, SE=.34, P = 0.004); positive expectancies also mediated the association between epistemic beliefs and mental HRQOL (Sobel Z=4.27, P\u3c0.001). CONCLUSIONS: Epistemic beliefs in limits to medical knowledge are associated with positive future expectancies and greater mental HRQOL; positive expectancies mediate the association between epistemic beliefs and HRQOL. More research is needed to confirm these relationships and elucidate their causal mechanisms

Health Links: Who Acts as a Source of Health Information in a Social Network?

Background: Members of a social network can influence the preventive health choices and cancer screening behaviors of other network members. Study Design: We conducted in-person interviews with 438 insured adults ages 40-70 in Massachusetts, Hawaii, and Georgia. We gathered information on social network communication regarding routine health topics and cancer screening. Participants reported whether family members and friends ask them for information or advice on health topics. Characteristics of each respondent’s social network were explored, including number of people with whom the participant has discussed colorectal cancer (CRC) screening. Participants were asked whether communication with social network members had ever led them to seek cancer screening. Principal Findings:80% of respondents in our group described themselves as a source of health information or advice for others in their social network (89% of women vs. 68% of men, p Conclusions: People who identified themselves as a source of health information within their social network were more likely to have discussed CRC screening with others and communicated with more people. Further study is necessary to understand the roles played by these individuals. As “health information ambassadors,” they may be effective targets for interventions that promote preventive screening

The HST Key Project on the Extragalactic Distance Scale. XV. A Cepheid Distance to the Fornax Cluster and Its Implications

Using the Hubble Space Telescope (HST) 37 long-period Cepheid variables have been discovered in the Fornax Cluster spiral galaxy NGC 1365. The resulting V and I period-luminosity relations yield a true distance modulus of 31.35 +/- 0.07 mag, which corresponds to a distance of 18.6 +/- 0.6 Mpc. This measurement provides several routes for estimating the Hubble Constant. (1) Assuming this distance for the Fornax Cluster as a whole yields a local Hubble Constant of 70 +/-18_{random} [+/-7]_{systematic} km/s/Mpc. (2) Nine Cepheid-based distances to groups of galaxies out to and including the Fornax and Virgo clusters yield Ho = 73 (+/-16)_r [+/-7]_s km/s/Mpc. (3) Recalibrating the I-band Tully-Fisher relation using NGC 1365 and six nearby spiral galaxies, and applying it to 15 galaxy clusters out to 100 Mpc gives Ho = 76 (+/-3)_r [+/-8]_s km/s/Mpc. (4) Using a broad-based set of differential cluster distance moduli ranging from Fornax to Abell 2147 gives Ho = 72 (+/-)_r [+/-6]_s km/s/Mpc. And finally, (5) Assuming the NGC 1365 distance for the two additional Type Ia supernovae in Fornax and adding them to the SnIa calibration (correcting for light curve shape) gives Ho = 67 (+/-6)_r [+/-7]_s km/s/Mpc out to a distance in excess of 500 Mpc. All five of these Ho determinations agree to within their statistical errors. The resulting estimate of the Hubble Constant combining all these determinations is Ho = 72 (+/-5)_r [+/-12]_s km/s/Mpc.Comment: Accepted for publication in the Astrophysical Journal, Apr. 10 issue 28 pages, 3 tables, 12 figures (Correct figures and abstract