Development and Simulation of Sulfur‐doped Graphene Supported Platinum with Exemplary Stability and Activity Towards Oxygen Reduction

Sulfur‐doped graphene (SG) is prepared by a thermal shock/quench anneal process and investigated as a unique Pt nanoparticle support (Pt/SG) for the oxygen reduction reaction (ORR). Particularly, SG is found to induce highly favorable catalyst‐support interactions, resulting in excellent half‐cell based ORR activity of 139 mA mg_Pt ^?1 at 0.9 V vs RHE, significant improvements over commercial Pt/C (121 mA mg_Pt ^?1) and Pt‐graphene (Pt/G, 101 mA mg_Pt ^?1). Pt/SG also demonstrates unprecedented stability, maintaining 87% of its electrochemically active surface area following accelerated degradation testing. Furthermore, a majority of ORR activity is maintained, providing 108 mA mg_Pt ^?1, a remarkable 171% improvement over Pt/C (39.8 mA mg_Pt ^?1) and an 89% improvement over Pt/G (57.0 mA mg_Pt ^?1). Computational simulations highlight that the interactions between Pt and graphene are enhanced significantly by sulfur doping, leading to a tethering effect that can explain the outstanding electrochemical stability. Furthermore, sulfur dopants result in a downshift of the platinum d‐band center, explaining the excellent ORR activity and rendering SG as a new and highly promising class of catalyst supports for electrochemical energy technologies such as fuel cells.     

Socioeconomic development, status of women, family planning, and fertility in Bangladesh: a district level analysis

In this paper we examine the effects of socioeconomic development, the status of women, and family planning on fertility and the extent to which these effects vary among the nineteen districts of Bangladesh. The 1983 and 1991 Bangladesh Contraceptive Prevalence Survey data are used to examine the effects of these factors on differences in contraceptive use among currently married women aged 15-49. The proportion of currently married women aged 15-49 using contraception was 46.3 per cent in 1991, a considerable increase from 26.5 per cent in 1983. Contraceptive use rates for all the districts increased substantially over the period between 1983 and 1991 and the gap between Dhaka's rate and those of other districts was narrower in 1991 than in 1983. An analytical model composed of socioeconomic development, status of women, and family planning variables is tested using logistic regression. The logit model is used to evaluate the effects of a selected group of variables on the probability of using contraceptive methods. The analysis demonstrates clearly that socioeconomic development and women's status significantly impact the use of contraceptive methods in Bangladesh. The results also suggest that better-educated, employed women are more likely to use contraception than those who have little or no formal education and who are not employed. In 1983, rural-urban differences in contraceptive use were significant, but in 1991 area of residence was not significant, which suggests that family planning programs may have played an important role in providing contraceptive information and technology to rural areas. Our analysis also suggests that family planning programs operated more efficiently in some districts than in others, and regional differences remained important in 1991 as they were in 1983. Decomposition analysis suggests that shifts in population structure favored increased contraceptive use in Bangladesh. This analysis also indicates that change in rate is also important, contributing about 21 per cent of the overall increase in contraceptive use.     

Increased matrix metalloproteinase-2 activity induced by TGF-beta 1 in duct cells of human salivary gland is associated with the development of cyst formation in vivo

Proteolytic enzyme activity has been shown to be important for cyst formation. In this study, we constructed a cyst-like structure in vivo and analyzed molecular mechanisms involved in the development of the lesion. When SV40-immortalized duct cells of normal human salivary gland (NS-SV-DC) were treated with TGF-beta 1 at a concentration of 1 ng/ml or 5 ng/ml followed by co-inoculation with Matrigel into the backs of nude mice, they formed large cysts containing fluid when 5 ng/ml of TGF-beta 1 was used. Analysis of the fluid demonstrated high MMP activity. Immunohistochemical staining exhibited strong reactivity with anti-MMP-2 antibody in TGF-beta 1 (5 ng/ml)-treated NS-SV-DC. Northern blot analysis indicated that the expression of TGF-beta 1 and MMP-2 mRNAs in cells was greatly enhanced by treatment with 5 ng/ml TGF-beta 1. These findings suggest that the in vivo cyst formation by TGF-beta 1-treated cells is associated with continuous induction of MMP-2 activity.     

Vancomycin administration in continuous ambulatory peritoneal dialysis: the risk of ototoxicity

Patients diagnosed with nodules (NO = 40) in a large university hospital clinic and an age-stratum matched nondiseased group (ND = 200) described adverse outcomes of vocal impairment on work and work-related communications. NOs were significantly more likely than NDs to report symptoms of hoarseness (73% vs. 26%), high-note difficulty (70% vs. 20%), difficulty speaking with a lower voice (53% vs. 13%) and a tired voice (50% vs. 10%), and their greatest source of physical discomfort was associated with scratchiness (61% vs. 3%). The average number of symptoms was four in NOs and less than one in NDs. Nodule patients were most concerned about the effects their voice problem would have on their future career (78% vs. 24%) and 49% of NOS reported their voice problem had an adverse work effect in the past compared with 4% of NDs. Having a voice condition limited current job performance in 39% of the NO group but only in 2% of the ND group. The results suggest that a diagnosis of nodules plays a major role in disrupting careers and work activities and that available educational programs and additional research are needed for improving their functional ability and preventing adverse outcomes in the lives of individuals with voice disorders.     

On the practicability of a new bio sorbent: Lasani sawdust and coconut coir for cleanup of oil spilled on water

In this article, two bio-sorbents have been selected: lasani sawdust (LS) (a new bio-based material) and coconut coir (CC) for the removal of used motor oil from the aqueous phase. The physical nature of the materials was characterized using Fourier Transform Infrared Spectroscopy and Constitutional Analysis of lignin and cellulose. The adsorption process was evaluated using various kinetic and adsorption models. The evaluated sorption capacities for coconut coir and lasani sawdust were 12.82?g g^?1 and 0.36?g g^?1, respectively. Maximum sorption of oil from the aqueous solution conveniently took place in 20?minutes. To ascribe statistically which model describes the adsorption phenomenon best, Root Mean Square Error (RMSE) and Average Relative Error (ARE) were used. The kinetics of the adsorption was best described by Pseudo-second order. Similarly, Langmuir isotherm model had the least value for the two error functions and a higher q_max value for coir than for lasani. It was concluded that the increased absorptive ability of coir over lasani was due to the difference in the composition of lignin and cellulose of the two materials.     

Predicting Drying Performance of Osmotically Treated Heat Sensitive Products Using Artificial Intelligence

The main goal of this research is to develop and apply a robust Artificial Neural Networks (ANNs) model for predicting the characteristics of the osmotically drying treated potato and apple samples as a model heat-sensitive product in vacuum contact dryer. Concentrated salt and sugar solutions were used as the osmotic solutions at 27C. Series of experiments were performed at various temperatures of 35C, 40C, and 55C for conduction heat input under vacuum ( −760 mm Hg) condition. Some experiments were also performed in a pure vacuum without heat addition. Dimensionless moisture content (DMC), effective moisture diffusivity, and mass flux were considered as the performance parameters in this study. Results revealed that the osmotic dehydration using a concentrated sugar solution shows a higher reduction in the initial moisture loss of 19.87% compared to 5.3% in the salt solution. Furthermore, a significant enhancement of drying performance of about 27% in DMC was observed for both samples at vacuum and 40C compared to pure vacuum drying conditions. Using the experimental data, a robust artificial neural network (ANN) was proposed to describe the osmotic dehydration’s behavior on the drying process. The ANN model outputs are the dimensionless moisture contents (DMC), the diffusivity, and the mass flux. Whereas the ANN inputs were the drying time, the percent of sugar solution, and the percent of salt solution. For the ANN apple’s model, the minimum root mean square error (RMSE) values were 0.0261, 0.0349 and 0.0406, for DMC, diffusivity, and mass flux, respectively. Whereas the best correlation coefficients of the above three parameters’ determination values were 0.9909, 0.9867 and 0.9744, respectively. For the ANN potato’s model, the minimum RMSE values were 0.0124, 0.0140 and 0.0333, for DMC, diffusivity, and mass flux, respectively. And the best correlation coefficients of the parameters’ values were found 0.9969, 0.9968 and 0.9736, respectively. Accordingly, the ANN model’s prediction has a perfect agreement with the experimental dataset, which confirmed the ANN model’s accuracy.     

Studies in the molecular weight distribution of epoxide resins. I. Gel permeation chromatography of epoxide resins

The molecular weight distributions as measured by gel permeation chromatography of solid epoxide resins made by the direct addition of epichlorohydrin to bisphenol A (the “taffy” process) and by the reaction of low molecular weight liquid epoxide resins whose main constituent is the diglycidyl ether of bisphenol A with bisphenol A (the “advancement” process) have been compared with the theoretical distribution calculated by the application of Flory statistics. The model used for predicting the molecular weight distribution has been shown to be too simple to describe the real size distribution of these resins. For resins prepared by the “taffy” process, incompleteness of reaction, the presence of monofunctional epoxides, and the possibility of branching reactions through the epoxide–hydroxyl reaction lead to a distribution that more nearly resembles one calculated for a resin having a higher epoxide value than that actually measured. In the case of resins prepared by the “advancement” process, the presence of small amounts of the higher oligomeric diepoxides and monofunctional epoxides in the starting material used for the synthesis lead to complex molecular weight distributions that are not easy to deduce theoretically. The experimentally determined molecular weight distributions for the higher molecular weight epoxide resins (epoxide value <2 eq/kg) made by the “advancement” process resemble more nearly those calculated for resins having lower epoxide values than those actually measured.     

Low adhesion,non-wetting phosphonate self-assembled monolayer films formed on copper oxide surfaces

Self-assembled monolayer (SAM) films have been formed on oxidized copper (Cu) substrates by reaction with 1H,1H,2H,2H-perfluorodecylphosphonic acid (PFDP), octadecylphosphonic acid (ODP), decylphosphonic acid (DP), and octylphosphonic acid (OP) and then investigated by X-ray photoelectron spectroscopy (XPS), contact angle measurement (CAM), and atomic force microscopy (AFM). The presence of alkyl phosphonate molecules, PFDP, ODP, DP, and OP, on Cu were confirmed by CAM and XPS analysis. No alkyl phosphonate molecules were seen by XPS on unmodified Cu as a control. The PFDP/Cu and ODP/Cu SAMs were found to be very hydrophobic having water sessile drop static contact angles of more than 140°, while DP/Cu and OP/Cu have contact angles of 119° and 76°, respectively. PFDP/Cu, ODP/Cu, DP/Cu, and OP/Cu SAMs were studied by friction force microscopy, a derivative of AFM, to better understand their micro/nanotribological properties. PFDP/Cu, ODP/Cu, and DP/Cu had comparable adhesive force, which is much lower than that for unmodified Cu. ODP/Cu had the lowest friction coefficient followed by PFDP/Cu, DP/Cu, and OP/Cu while unmodified Cu had the highest. XPS data gives some indication that a bidentate bond forms between the alkyl phosphonate molecules and the oxidized Cu surface. Hydrophobic phosphonate SAMs could be useful as corrosion inhibitors in micro/nanoelectronic devices and/or as promoters for anti-wetting, low adhesion surfaces.     

Work Stress, Support, and Mental Health in Construction

Construction professionals are subjected to a plethora of occupational demands that can have a negative effect on their psychological wellbeing. Such demands can have an adverse influence on individual and organizational performance. To investigate the nature of self and social supports and mental health among construction professionals, an exploratory study was undertaken using the Stress and Mental Health Survey. The survey was distributed to construction professionals throughout Australia and 449 responses were received. Analysis revealed that those working for a contracting organization on-site reported higher levels of poor mental health and greater work stress than consultants. Those working on-site also experienced greater levels of self-stress, whereas consultants reported higher levels of self and work support. Work support was a significant predictor of poor mental health for consultants. Good health, however, was predicted by self, situational, and work support, whereas those working for a contractor only self-support predicated good mental health. It is concluded that while supports are essential in the fostering of good mental health, the absence of these supports can have a significant impact on poor mental health.