Search

In photocatalytic water splitting, fluidization is known to minimize the adverse effects of mass-transfer, poor radiation distribution, parasitic back-reactions and photocatalyst handling difficulties, which limit the scalability of immobilized-film and suspended slurry photocatalysts. Fluidization of one-dimensional TiO

Vertically aligned 2.45 μm anatase nanowires were produced via a simple chemical bath deposition technique using a low-cost, easy to handle, water-soluble titanium salt precursor. The nanowires wer...

We reviewed our experience of morbidly obese patients with end-stage heart failure that underwent left ventricular assist device (LVAD) implantation. From January 1, 2008 to January 1, 2018, 240 adult LVADs were implanted at our center. We reviewed the cases of patients presenting with end-stage heart failure and morbid obesity (preoperative body mass index [BMI] ≥ 35 kg/m2) who underwent LVAD-alone, and compared that to a group that underwent LVAD and bariatric surgery (laparoscopic sleeve gastrectomy [LSG]) as a means for weight reduction. Demographic characteristics, perioperative details, BMI, and status of transplant candidacy were recorded. Statistical analysis was performed (SPSS version 25) with χ2 analysis, Kaplan-Meier survival analysis, regression analysis, and Student's t-test. Twenty-nine patients met criteria and underwent LVAD implantation. Fifteen patients underwent LVAD-alone. Fourteen patients underwent LVAD + LSG. Both groups showed good survival outcomes, LVAD-alone (88.9 ± 5.9 months) versus LVAD +LSG (96.1 ± 12.4 months) but were not significantly different. However, we did note that more patients in the LVAD + LSG group were bridged to heart transplantation (p < 0.001). LVAD-alone and/or LVAD + LSG are both technically feasible and effective treatment options for the long-term survival of morbidly obese patients with end-stage heart failure. Combining LVAD + LSG can help bridge patients to heart transplantation.

Photocatalytic water splitting in a novel, UV-irradiated fluidized bed reactor system with Pt-deposited titanium dioxide (TiO2) particles has been explored as an alternative approach to hydrogen production. A model describing the water splitting performance of the fluidized bed system was developed through a holistic approach combining fluidized bed theory, mass transfer effects, an optical model, and a proposed mechanism for the parasitic Pt-catalysed back reaction of H2 and O2. The model was validated experimentally using fluidizable Pt-deposited TiO2 particles. It was found that the efficiency of the fluidized bed water splitting system is dependent on the rate of mass transfer in the gas–liquid separator, while the overall rate of hydrogen evolution was found to vary with the height and density of the photocatalyst bed in the reactor; all of which are functions of the fluidization flow rate. It is shown that maximizing the rate of mass transfer in the gas–liquid separator can greatly diminish losses due to the Pt-catalysed back reaction of H2 and O2, yielding significant gains in efficiency and the overall rate of hydrogen production. The application of the model to the design of the fluidized bed water splitting system, the sub-systems and the photocatalyst particles is discussed.

UV-irradiated fluidized bed reactor system and Pt-loaded TiO2 spheres were developed for photocatalytic water splitting. This novel approach was explored as a means to minimize the parasitic back reaction, mass transport and radiation distribution effects that limit the performance and scalability of immobilized-film and suspended slurry photocatalysts typically employed for photocatalytic hydrogen production. By fluidizing Pt-loaded TiO2 spheres in a 2.2 M Na2CO3 solution, steady hydrogen production rates up to 211 μmol/h with an apparent quantum efficiency of 1.33% were achieved upon UV-irradiation. This demonstrates a marked 44% increase in the apparent quantum efficiency when compared to the performance of a traditional Pt-loaded TiO2 suspended slurry photocatalyst in the same reactor. It is hypothesized that this enhanced performance is primarily due to improved separation of the evolved H2 and O2 from the Pt-loaded photocatalyst particles, thus reducing the parasitic back reaction.

Quantifying sporadic waterborne infections in community settings can be challenging. Salivary antibody immunoassays are a promising non-invasive tool that can be used in prospective studies of common infections, especially those involving children. This study was conducted in a Massachusetts city, which uses a microbiologically contaminated river as its water source, during summer-early winter periods before and after construction of a new drinking water treatment plant. Monthly saliva samples (7,480 samples from 1,170 children and 816 adults) were analyzed for immunoglobulin G (IgG) responses to recombinant proteins of Cryptosporidium, one genogroup I (GI) and two GII noroviruses. Immunoconversion was defined as at least four-fold increase in specific antibody responses between two monthly samples with a post-conversion response above a flexible age-dependent cut-off. Episodes of gastroenteritis (diarrhea or vomiting or cramps) were associated with 3.2 (95% confidence limits 1.1; 9.5) adjusted odds ratio (aOR) of immunoconversion to Cryptosporidium; episodes of combined diarrhea and vomiting symptoms were associated with 3.5 (0.8; 15.0) and 4.6 (1.7; 12.6) aORs of an immunoconversion to GI and GII noroviruses respectively. Swimming in natural water bodies or chlorinated pools was associated with 2.3 (0.4; 15.4) and 4.9 (1.6; 15.5) aORs of immunoconversion to Cryptosporidium, respectively. In a subset of study participants who did not use home water filters, consumption of at least some amount of non-boiled tap water reported in a monthly recall survey was associated with 11.1 (1.2; 100.0) and 0.6 (0.1; 2.5) aORs of immunoconversion to Cryptosporidium before and after the new water treatment plant construction, respectively. Among individuals who used home water filters, associations between non-boiled tap water consumption and Cryptosporidium immunoconversion were not significant before and after new plant construction with aORs of 0.8 (0.2; 3.3) and 0.3 (0.1; 1.6), respectively. The interaction effect of study phase and non-boiled tap water consumption on Cryptosporidium immunoconversions was statistically significant in the entire study population with aOR of 5.4 (1.1; 25.6). This was the first study that has used a salivary antibody immunoassay to demonstrate significant associations between gastrointestinal symptoms and Cryptosporidium and norovirus infections, and between water-related exposures and Cryptosporidium infections.

In this study, a simple and reproducible synthesis strategy was employed to fabricate TiO2 microspheres with hierarchical nanostructure. The microspheres are macroscopic in the bulk particle size (several hundreds to more than 1000 μm), but they are actually composed of P25 nanoparticles as the building units. Although it is simple in the assembly of P25 nanoparticles, the structure of the as-prepared TiO2 microspheres becomes unique because a hierarchical porosity composed of macropores, larger mesopores (ca. 12.4 nm), and smaller mesopores (ca. 2.3 nm) has been developed. The interconnected macropores and larger mesopores can be utilized as fast paths for mass transport. In addition, this hierarchical nanostructure may also contribute to some extent to the enhanced photocatalytic activity due to increased multilight reflection/scattering. Compared with the state-of-the-art photocatalyst, commercial Degussa P25 TiO2, the as-prepared TiO2 microsphere catalyst has demonstrated significant enhancement in photodriven conversion of CO2 into the end product CH4. Further enhancement in photodriven conversion of CO2 into CH4 can be easily achieved by the incorporation of metals such as Pt. The preliminary experiments with Pt loading reveal that there is still much potential for considerable improvement in TiO2 microsphere based photocatalysts. Most interestingly and significantly, the synthesis strategy is simple and large quantity of TiO2 microspheres (i.e., several hundred grams) can be easily prepared at one time in the lab, which makes large-scale industrial synthesis of TiO2 microspheres feasible and less expensive.

We examine the theoretical, empirical, and public policy implications of the proportion of females in the establishment. Arrow's model of heterogeneous employer discrimination provides predictions that are tested. Empirical results indicate support for the theory using establishment data, but a contradiction is obtained with the individual data. It is estimated that the proportion of females in the establishment accounts for 26 per cent of the gender log wage gap. Implications for employment equity are considered in the context of a new method of decomposing the log wage gap and indicate that such public policy can reduce this gap by 20 per cent.

This paper describes the results of an industry effo rt to test Bio-derived Synthetic Paraffinic Kerosene (Bio-SPK) from natural plant oils. The program included the identification and sourcing of sustainable feedstocks, the use of a new fuel processing method, nu merous fuel tests, engine operability, performance and emissions tests, and flight testing in three Boeing aircraft models. The Bio-SPK blended fuels have potential to reduce life cycle CO2 emissions and be compatible with current aircraft, systems, and infrastructure.

In this paper we examine three implementation and interpretation issues associated with Krueger and Summers’s (1988) method for calculating interindustry wage differentials. The literature tends to report a less than complete set of industry wage differentials; use the wrong standard errors; and misinterpret the meaning of the industry wage differentials. The solution to the first two issues follows from making explicit the restriction that the employment-weighted average of all industry wage effects is zero, the same restriction that Krueger and Summers are implicitly imposing on industry wage effects. All industries have thus a wage effect relative to an average worker net of any industry effect and correct standard errors are available via the Delta Method. Finally, we propose a method for analysing interindustry wage differentials as actual differences between wage levels expressed in percentage points and not as log points, which is the current misleading standard. Our procedure calculates actual average percentage wage differences by industry and avoids the distortion in differences across industries that log point comparisons engender. An application is provided, using the United States Outgoing Rotation Files of the Current Population Survey for 1989 and 1996 and so updates the work by Krueger and Summers (1988). (JEL: C12 and J31)

The purpose of this study was to evaluate changes in physiologic parameters seen in a group of patients with chronic low back syndrome assigned to supervised and independent strength and conditioning programs. Forty patients with chronic low back syndrome were assigned either to a control group (independent exercise) or to an experimental group (supervised exercise). All subjects underwent pre-testing for aerobic fitness, strength and responses to visual analog pain rating scales. Twenty control subjects were given predesigned exercise programs and told to exercise four times per week for 6 months. Twenty experimental subjects were given predesigned exercise programs but were monitored by a strength and conditioning specialist for the same period. Statistically significant results were seen for increases in aerobic fitness and strength, decreases in reported pain, and percent body fat in the experimental group. Since the experimental group completed 90.75 sessions out of 96, compared with 31.95 for the control group, it could be concluded that supervision increases chances for compliance and success as measured by these parameters.

In this study, the diversity of organisms identified by using standard plate count (SPC) and membrane filtration strongly suggests an established microbial ecosystem in two distribution systems. The SPC exhibited no relationship with coliform count when the SPC was less than 50 organisms/ml. The SPC was not dependent on low-level turbidity and varied with respect to free chlorine residuals. The frequency of coliform isolation was independent of turbidity and free chlorine. Specifically, encapsulated coliforms (Klebsiella pneumoniae, Enterobacter cloacae, E. aerogenes, and E. agglomerans), which gave typical coliform results, exhibited the ability to survive a free chlorine residual of 0.2 mg/L or more. Encapsulation was a major factor in all of these results.

Since the discovery of photocatalytic watersplitting over titanium dioxide (TiO 2 ), researchers have typically only employed immobilized-film and suspended slurry photocatalysts. Here we present watersplitting in a UV- irradiated fluidized bed reactor with a novel, fluidizable watersplitting photocatalyst. This approach was taken to address the mass-transfer effects, poor radiation distribution, parasitic back-reaction and photocatalyst handling difficulties that limit the efficiency and scalability of existing watersplitting systems. Using a 2.2 M Na 2 CO 3 solution, significant hydrogen production rates were achieved. A marked increase in the hydrogen production rate was observed when compared to results obtained by a suspended slurry TiO 2 photocatalyst in the same reactor.