Thermal transport and chemical conversion in single reacting sorbent particles

The effects of particle size and carbon dioxide concentration on chemical conversion in engineered spherical particles undergoing calcium oxide looping are investigated. Particles are thermochemically cycled in a furnace under different carbon dioxide concentrations. Changes in composition due to chemical reactions are measured using thermogravimetric analysis. Gas composition at the furnace exit is evaluated with mass spectroscopy. A numerical model of thermal transport phenomena developed previously is adapted to match the physical system investigated in the present study. The model is used to elucidate effects of reacting medium characteristics on particle temperature and reaction extent. Experimental and numerical results show that (1) an increase in particle size results in a decrease in carbonation extent, and (2) the carbonation step consists of fast and slow reaction regimes. The reaction rates in the fast and slow carbonation regimes increase with increasing carbon dioxide concentration. The effect of carbon dioxide concentration and the distinction between the fast and slow regimes become more pronounced with increasing particle size.     

The formation of active species for oxidative dehydrogenation of propane on magnesium molybdates

Pure and mixed magnesium molybdate phases (MoO₃, MgMoO₄, and MgMo₂O₇) have been examined for the oxidative dehydrogenation reaction of propane. The results are very sensitive to the stoichiometry and method of preparation. The catalysts exhibiting superior activity and selectivity are characterized by a unique temperature-programmed reduction peak that is not present for the poorly active or selective catalysts. Mixtures of MgMoO₄ and MoO₃ or MgMoO₄ and MgMo₂O₇, materials that perform poorly by themselves, show significant improvements in performance upon heating. The solid-state interactions leading to these improvements correspond to the appearance of the characteristic reduction peak. The results suggest that the beneficial synergistic effects seen with mixtures of inactive phases are due to formation of a new phase or species, rather than remote communication between phases (e.g., oxygen spillover). This revised version was published online in November 2006 with corrections to the Cover Date.     

Social support as a moderator of the relationship between recent history of depression and smoking cessation among lower-educated women.

We examined psychosocial mechanisms linking recent history of depression and subsequent short-term smoking cessation. Our sample included lower-educated women smokers who registered for a brief cessation intervention (registrant panel; n = 1,198), and a quasicontrol panel not participating in the intervention (population panel; n = 682). Women were surveyed by telephone every 6 months for a period of 2 years, measuring psychosocial variables (motivation, self-efficacy, perceived stress, and social support) and self-reported smoking status (7-day abstinence) at each point. In both panels, smoking rate and self-efficacy were strong independent predictors of subsequent cessation, but recent history of depression (as measured 6 months earlier) was not a significant predictor. However, among only the registrant panel, the effects of recent history of depression were significantly moderated by social support. Recently depressed women who had higher levels of perceived social support were as likely to quit subsequently as women who did not have a recent history of depression. The determinants of successful quitting among lower-educated women differ between those who seek assistance and those who do not.     

Salinity tolerance of the invasive round goby: Experimental implications for seawater ballast exchange and spread to North American estuaries

The Eurasian round goby (Neogobius melanostomus) invaded the freshwater North American Great Lakes in ~ 1990 via accidental introduction from ballast water discharge. Its genotypes in the Great Lakes traced to estuaries in the northern Black Sea, where the round goby flourishes in a variety of salinities to 22 parts per thousand (ppt). To prevent further introductions, U.S. and Canadian Coast Guard regulations now require that vessels exchange ballast water at sea before entering the Great Lakes. Since salinity tolerance of the invasive round goby population is poorly understood, we tested 230 laboratory-acclimated fish in three experimental scenarios: (1) rapid salinity increases (0–40 ppt), simulating ballast water exchange, (2) step-wise salinity increases, as during estuarine tidal fluxes or migration from fresh to saltwater, and (3) long-term survivorship and growth (to 4 months) at acclimated salinities. Almost all gobies survived experiments at 0–20 ppt, whereas none survived ≥ 30 ppt, and at 25 ppt only 15% withstood rapid changes and 30% survived step-wise increases. Ventilation frequencies were lowest at 10–15 ppt in step-wise experiments, in conditions that were near isotonic with fish internal plasma concentrations, reflecting lower energy expenditure for osmoregulation. Growth rates appeared greatest at 5–10 ppt, congruent with the larger sizes reached by gobies in Eurasian brackish waters. Thus, we predict that the Great Lakes round goby would thrive in brackish water estuaries along North American coasts, if introduced. However, oceanic salinities appear fatal to the invasive round goby, which likely cannot withstand complete seawater ballast exchanges or oceanic habitats.     

Impact of bacterial stress and biofilm-forming ability on transfer of surface-dried Listeria monocytogenes during slicing of delicatessen meats

Listeria monocytogenes contamination of delicatessen slicer blades can lead to cross-contamination of luncheon meats. A cocktail of 3 strong or 3 weak biofilm-forming strains of L. monocytogenes suspended in turkey slurry was used to inoculate stainless steel delicatessen slicer blades at a level of 6 log CFU/blade. The cocktails were used with or without injury (cold-shocked at 4 degrees C for 2 h, or chlorine-injured at 100 ppm for 1 min). Inoculated blades were held at 22 degrees C/78+/-2% relative humidity for 6 and 24 h, before being used to generate 30 slices from chubs of roast turkey breast or Genoa salami. Slices (25 g) were diluted 1:5 in University of Vermont Medium, homogenized by stomaching and then pour-plated using tryptose phosphate agar supplemented with esculin and ferric ammonium citrate. Greater cumulative transfer to the 30 slices was seen for the strong (3.62 log CFU) as opposed to weak biofilm-forming cocktails (3.12 log CFU) with transfer also significantly greater to turkey (3.61 log CFU) than to salami (3.12 log CFU). Among the three treatments, cold-shock significantly increased subsequent L. monocytogenes transfer (3.69 log CFU) compared to the uninjured control (3.30 log CFU) and chlorine-injury (3.12 log CFU). Significantly greater transfer was also seen for blades used after 6 as opposed to 24 h of incubation. Differences in product composition and survival of L. monocytogenes, as seen via viability staining, are likely reasons for these observed differences in transfer.     

Synthesis of Organotin Polyesters from Reaction of the Salt of <Emphasis Type="SmallCaps">d</Emphasis>-Camphoric Acid and Organotin Dihalides and Initial Anticancer Activity

Organotin polyesters were synthesized from d-camphoric acid. Since d-camphoric acid is a natural product, this is part of the green chemistry initiative. Further, synthesis occurred employing commercially available reactants and the interfacial system which is used industrially to synthesize aramids and polycarbonates. Thus, scale-up is straightforward. Polymers were synthesized employing the interfacial reaction between various organotin dihalides and the salt of d-camphoric acid. Reaction was rapid occurring in 30 s and less. Product yield was good except for the product from dioctyltin dichloride. The products are polymeric with chain lengths from 230 to 2200. Structural characterization with infrared spectrometry and MALDI MS are consistent with the formation of organotin polyesters containing the camphoric acid moiety within its backbone. IR shows formation of the Sn–OOC(O) linkage with the polymer having a combination of bridging and non-bridging geometrical arrangements about the tin atom. MALDI MS shows ion fragment to two and three repeat units. The products exhibit good ability to inhibit a battery of cancer cells including those from pancreatic cancer. The effective concentration for inhibition of the cancer cell lines are generally in the same range as those found for cisplatin and in the ng/mL range.     

Group IVB metallocene polyesters containing camphoric acid and preliminary cancer cell activity

Polyesters were formed from the reaction of the salt of camphoric acid and Group IVB metallocene dichlorides using the interfacial polycondenzation process. The polyesters were formed in good yields with moderate chain lengths. Fourier transform infrared spectroscopy shows bands characteristic of the presence of both reactants with new bands characteristic of the formation of the M?O and M–O(CO) linkage present. The polymers largely exist in a bridging geometry of the carbonyl groups about the metal atom. Nuclear magnetic resonance shows the presence of bands derived from both reactants. Matrix-assisted laser desorption/ionization mass spectroscopy shows ion fragments to three units for the polymers with isotopic abundance characteristic of the presence of metal atoms in the ion fragment clusters. All the polymers exhibit good ability to inhibit all the tested cancer cell lines but the zironocene and hafnocene polymers exhibit especially good inhibition of the tested cancer cell lines that included two pancreatic cancer cell lines. They represent a potential new group of anticancer drugs.     

Exercise referral: the public health panacea for physical activity promotion? A critical perspective of exercise referral schemes; their development and evaluation

This review critically explores the development, impact and evaluation of exercise referral schemes (ERS) in the UK. A rapid expansion in the use of such ERSs has been recorded throughout leisure and primary care settings, but the evidence underpinning their implementation has been sparse and predominantly limited to randomized control trial (RCT) research design. Consequently, understanding of exercise referral as a 'real world' intervention has been limited. Considering the increasing importance being placed on evidence-based practice and clinical effectiveness, it is no longer sufficient for service providers of exercise referral to ignore the need to evaluate schemes. The guidelines on evaluation provided by the National Quality Assurance Framework for Exercise Referral are limited, hence practitioners are often unsure of the best measures to use when assessing effectiveness. Predominantly, exercise professionals focus on the collection of physiological data but tend to ignore relevant psychological and environmental parameters. Also, few UK studies have followed participants up in the long term, to see if physical activity behaviour is sustained over time. Here, evidence from two on-going, large-scale (n = 1600/annum) evaluation studies of exercise referral schemes, based in urban localities in the northwest of England, are described. A participatory action research framework for evaluation was utilized and incorporated multi-method research approaches for the assessment of both ERS participants and health professionals involved in intervention delivery. This framework is an appropriate methodology for the evaluation and development of complex interventions, and here incorporates case study, focus groups, interviews and survey questionnaires. Included was a 12-month tracking study of a cohort of exercise referral participants (n = 342), which measured leisure-time physical activity levels (Godin leisure time score), at baseline (entry to exercise referral) and at 3 monthly intervals thereafter. Adherence to the ERS was approximately 35-45%, with the older participants more likely to complete. Physiological changes during the ERS, although statistically significant, were not of a magnitude to convey any real health benefit to an individual's health status. Although small in scale, physiological changes were all in a positive direction (e.g. reduction in blood pressure) and, if maintained over time, could bring about population-level benefits in health. Participants referred from cardiac and practice nurses had higher levels of adherence than participants referred by general practitioners. Scheme B showed that the participants who adhered (n = 103) until the end of the ERS (12 weeks) were able to sustain a small increase in physical activity at the end of 12 months (increase of 21 min moderate activity/week compared with baseline). In conclusion, this research shows that the process of exercise referral benefits certain segments of the population, but not necessarily all.     

A randomized controlled trial of cognitive-behavioral therapy, light therapy, and their combination for seasonal affective disorder.

This first controlled psychotherapy trial for seasonal affective disorder (SAD) compared SAD-tailored cognitive-behavioral therapy (CBT), light therapy (LT), and their combination to a concurrent wait-list control. Adults (N = 61) with major depression, recurrent with seasonal pattern, were randomized to one of four 6-week conditions: CBT (1.5-hr twice-weekly group therapy), LT (10,000-lux for 90-min/day with administration time individually adjusted), combined CBT + LT, or a minimal contact/delayed LT control (MCDT; LT following 6 weeks of monitoring). CBT, LT, and CBT + LT significantly and comparably improved depression severity relative to MCDT in intent-to-treat and completer samples. CBT + LT (73%) had a significantly higher remission rate than MCDT (20%). Using prospectively measured summer mood status to estimate the "functional" population, CBT + LT also had a significantly larger proportion of participants with clinically significant change over treatment compared with MCDT. The LT condition outcomes virtually replicated results from prior trials. CBT, alone or combined with LT, holds promise as an efficacious SAD treatment and warrants further study. If replicated, CBT + LT's remission rate would represent a clinically meaningful improvement over the 53% observed across LT studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)