Development of a PtSn bimetallic catalyst for direct fuel cells using bio-butanol fuel.

Pt and PtSn catalysts were studied for n-butanol electro-oxidation at various temperatures. PtSn showed a higher activity towards butanol electro-oxidation compared to Pt in acidic media. The onset potential for n-butanol oxidation on PtSn is ∼520 mV lower than that found on Pt, and significantly lower activation energy was found for PtSn compared with that for Pt.

Correction: Real-space evidence of the equilibrium ordered bicontinuous double diamond structure of a diblock copolymer.

Correction for 'Real-space evidence of the equilibrium ordered bicontinuous double diamond structure of a diblock copolymer' by C. Y. Chu et al., Soft Matter, 2015, 11, 1871-1876.

Real-space evidence of the equilibrium ordered bicontinuous double diamond structure of a diblock copolymer.

The ordered bicontinuous double diamond (OBDD) structure has long been believed to be an unstable ordered network nanostructure, which is relative to the ordered bicontinuous double gyroid (OBDG) structure for diblock copolymers. Using electron tomography, we present the first real-space observation of the thermodynamically stable OBDD structure in a diblock copolymer composed of a stereoregular block, syndiotactic polypropylene-block-polystyrene (sPP-b-PS), in which the sPP tetrapods are interconnected via a bicontinuous network with Pn3̄m symmetry. The OBDD structure underwent a thermally reversible order-order transition (OOT) to OBDG upon heating, and the transition was accompanied with a slight reduction of domain spacing, as demonstrated both experimentally and theoretically. The thermodynamic stability of the OBDD structure was attributed to the ability of the configurationally regular sPP block to form helical segments, even above its melting point, as the reduction of internal energy associated with the helix formation may effectively compensate the greater packing frustration in OBDD relative to that in the tripods of OBDG.

The effects of the specific adsorption of anion on the reactivity of the Ru(0001) surface towards CO adsorption and oxidation: in situ FTIRS studies.

The dynamics of adsorption and oxidation of CO on Ru(0001) electrode in sulfuric acid solution have been studied using in situ FTIR spectroscopy under potential control and at open circuit, the latter at 20 and 55 degrees C. The in situ IR data show clearly that the bisulfate anion adsorbs on the Ru(0001) surface over the potential range from -200 mV to 350 mV (vs. Ag/AgCl) at 20 degrees C in the absence and presence of adsorbed CO; however, increasing the temperature to 55 degrees C and/or increasing the concentration of dissolved O(2) reduces the bisulfate adsorption. The formation of surface (hydro-) oxide at higher potentials replaces the bisulfate adsorbates. Both linear (CO(L)) and three-fold hollow bonded CO (CO(H)) adsorbates were produced following CO adsorption at Ru(0001) in H(2)SO(4), as was observed in our previous studies in HClO(4). However, the amount of adsorbed CO observed in H(2)SO(4) was ca. 10% less than that in HClO(4); in addition, the CO(L) and CO(H) frequencies were higher in H(2)SO(4), and the onset potential for CO(ads) oxidation 25 mV lower. These new results are interpreted in terms of a model in which the adsorbed bisulfate weakens the CO adlayer, allowing the active Ru oxide layer to form at lower potentials. Significantly different results were observed at open circuit in H(2)SO(4) compared both to the data under potential control and to our earlier data in HClO(4), and these observations were rationalized in terms of the adsorbed HSO(4)(-) anions (pre-adsorbed at -200 mV) inhibiting the oxidation of the surface at open circuit (after stepping from the initial potential of -200 mV), as the latter was no longer driven by the imposed electrochemical potential but via chemical oxidation by trace dissolved O(2). Results from experiments at open circuit at 55 degrees C and using oxygen-saturated H(2)SO(4) supported this model. The difference in Ru surface chemistry between imposed electrochemical control and chemical control has potential implications with respect to fuel cell electrocatalysis.

A novel electrochemical device for the disinfection of fluids by OH radicals.

This paper describes a novel, composite device, based not on optical excitation but on the transfer of holes from Si to the TiO(2)/air or TiO(2)/water interface, for the disinfection and detoxification of fluid streams.

In situ FTIR studies on the effect of temperature on the electro-oxidation of small organic molecules at the Ru(0001) electrode.

The adsorption and electro-oxidation of formaldehyde, formic acid and methanol at the Ru(0001) electrode in perchloric acid solution have been studied as a function of temperature, potential and time using in situ FTIR spectroscopy, and the results interpreted in terms of the surface chemistry of the Ru(000 1) electrode and compared to those obtained during our previous studies on the adsorption of CO under the same conditions. It was found that no dissociative adsorption or electro-oxidation of methanol takes place at Ru(0001) at potentials < 900 mV vs. Ag/AgCl, and at all three temperatures employed, 10, 25 and 50 degrees C. However, both formaldehyde and formic acid did undergo dissociative adsorption, even at -200 mV, to form linear (CO(L)) and 3-fold-hollow (COH) binding CO adsorbates. In contrast to the adsorption of CO, it was found that increasing the temperature to 50 degrees C markedly increased the amount of CO adsorbates formed on the Ru(0001) surface from the adsorption of both formaldehyde and formic acid. On increasing the potential, the electro-oxidation of the CO adsorbates to CO2 took place via reaction with the active (1 x 1)-O oxide. Formic acid was detected as a partial oxidation product during formaldehyde electro-oxidation. At all three temperatures employed, it was found that adsorbed CO species were formed from the adsorption of both formic acid and formaldehyde, and were oxidised to CO2 faster than was observed in the experiments involving CO adsorbed from CO(g), suggesting a higher mobility of the CO adsorbates formed from the adsorption of the HCOOH and HCHO. At potentials > 1000 mV, both the oxidation of formic acid to CO2 and the oxidation of formaldehyde to both CO2 and formic acid were significantly increased, and the oxidation of methanol to CO2 and methyl formate was observed, all of which were attributed to the formation of an active RuO2 phase on the Ru(0001) surface.

Relationship between pterygium/pinguecula and sunlight exposure among postmen in central Taiwan.

BACKGROUND: The purpose of this study was to investigate outdoor hazards and their relationship to conjunctival disorders experienced by postmen. METHODS: Three hundred and ninety-four employees (248 postmen and 146 officers) working in 11 post offices in central Taiwan were recruited and participated in the 1994 annual labor health examination. Pinguecula and pterygium were diagnosed by an ophthalmologist. Meanwhile, detailed personal and occupational information was obtained using a structured questionnaire. The cumulative occupational sunlight exposure was calculated for each postman by considering the duration of their employment as postmen, the average working hours per day and their spectacle use (sunglasses and eyeglasses). A logistic regression was used to analyze the relationship between cumulative occupational sunlight exposure and pinguecula. RESULTS: Among the postmen, the prevalences of pinguecula and pterygium were 62.9% and 7.3%, respectively. The outdoor nature of postal work was significantly associated with the occurrence of pinguecula as well as pterygium (p < 0.05). When the cumulative occupational sunlight exposure increased by one unit (one year x hour/day), the risks of developing pinguecula and pterygium were raised by 2.1% and 0.8%, respectively. CONCLUSIONS: The results indicate that conjunctival disorders were associated with the cumulative occupational sunlight exposure of postmen working outdoors. This study reinforces the importance of ocular protection from sunlight.

Growth and Survival of Salmonella montevideo on Tomatoes and Disinfection with Chlorinated Water.

The survival on tomato fruits ( Lycopersicum esculentum ) of a rifampicin-resistant strain of Salmonella montevideo (Centers for Disease Control and Prevention [CDC] isolate G4639), the alleged source of the 1993 multistate outbreak of salmonellosis, was affected by inoculum dose and inoculation site (unbroken surface or wounds and stem scars), as well as by the medium (distilled water, Butterfield's buffer, or trypticase soy broth [TSB]) used to deliver the bacterium, This bacterium inoculated at 4 log10 CFU (colony forming units) per site in distilled water survived for 20 h on tomato skin. However, comparable survival occurred at the stem scars and growth cracks with smaller inoculum doses (3 log10 CFU). The bacterial populations increased rapidly on puncture wounds and tomato slices but decreased on the unbroken surface and stem scar. With unbroken skin and approximately 4 log10 CFU per site, the population survived for at least 48 h but could not be consistently detected after 5 days. By contrast, the stem scar population survived for at least 7 days and decreased only 1 to 2 log10 units. The inherently low pH of the tomatoes did not inhibit bacterial growth. Treatment with 100 ppm of aqueous chlorine for up to 2 min failed to kill all bacteria at these inoculation sites. This was especially true when the bacterial suspensions were prepared in TSB. TSB supported better bacterial survival and/or growth and also protected against the bactericidal effect of aqueous chlorine.

[Clinical applications of CA 125 carcinoma of the ovary]. / Aplicações clínicas do CA 125 no carcinoma de ovário.

Cancer of the ovary is one of the most common causes of death among gynecologic neoplasms. As it is relatively "protected" by the peritoneal cavity, there is great need of methods to improve early diagnosis and to assist with the management of patients with this disease. An important advance was observed with the application of monoclonal antibodies. After 1983, most papers have mentioned CA 125 as a biochemical marker of ovarian non-mucinous cancer. The purpose of the authors is to discuss the controversial aspects of this important marker and its role in the diagnosis and follow-up of ovarian carcinoma. All being considered, clinical applications, post-treatment follow-up, and flaws can be established.