Harnessing social dynamics through persuasive technology to promote healthier lifestyle

In light of current calls by medical professionals to confront the global issue of obesity and related illnesses, we developed a mobile application called STEP UP that monitors physical activity and provides data that can be easily shared within a social network. We then conducted an exploratory, theoretical study based on the theory of reasoned action (TRA) followed by an experimental trial and user study. The purpose of the studies was to explore the effect of persuasive technology on physical activity behavior and to investigate its effectiveness in motivating users to use the technology to be more physically active. The application was found to have a positive effect on the participants and their level of physical activity. They enjoyed using the application and were motivated to walk more, especially when enabled to share their step counts with their friends. The social component of the application clearly enhanced users’ walking experience, as the atmosphere of friendly competition motivated them to walk more. Based on user responses, we conclude that a further enhanced application that includes chat functionality may be even more successful in supporting increased physical activity and thus healthier lifestyle.     

MOLECULAR APPROACH TO MATERIAL DETACHMENT MECHANISM DURING CHEMICAL MECHANICAL PLANARIZATION

Mechanistic numerical analysis and molecular dynamics (MD) simulation are employed to understand the material detachment mechanism associated with chemical mechanical polishing. We investigate the mechanics of scratch intersection mechanism to obtain a characteristic length scale and compare the theoretical predictions with previous experimental observations on ductile copper discs at the micro-scale. First, an analytical model is developed based on mechanics of materials approach. The analytical model includes the effects of strain hardening during material removal as well as the geometry of indenter tip. In the next step, molecular simulations of the scratch intersection are performed at the atomistic scale. The embedded atom method (EAM) is utilized as the force field for workpiece material and a simplified tool-workpiece interaction is assumed to simulate material removal through scratch intersection mechanism. Both models are utilized to predict a characteristic length of material detachment related to material removal during scratch intersection. The predictions from two approaches are compared with experimental observations in order to draw correlations between experiment and simulation. The insights obtained from this work may assist in understanding the mechanism for chemical mechanical planarization (CMP), and even be applied to other different machining and polishing events.     

Phase Transformation of Metastable ZnSnO3 Upon Thermal Decomposition by In‐Situ Temperature‐Dependent Raman Spectroscopy

Temperature‐dependent in‐situ Raman spectroscopy is used to investigate the phase transformation of zinc metastannate (ZnSnO₃) to zinc orthostannate (Zn₂SnO₄) induced upon annealing in the ambient. ZnSnO₃ microcubes (MCs) were synthesized at room temperature using a simple aqueous synthesis process, followed by characterization using electron microscopy, X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). Annealing of the ZnSnO₃ MCs was carried out up to 1000°C, while recording the Raman spectra in‐situ at regular intervals. Phase transformation from metastannate to orthostannate was found to begin around 500°C with an activation energy of ~0.965 eV followed by the recrystallization into the inverse spinel orthostannate phase at ~750°C. Results from this study provide detailed understanding of the phase transformation behavior of perovskite ZnSnO₃ to inverse spinel Zn₂SnO₄ upon thermal annealing.     

Prediction models for sewer infrastructure utilizing rule-based simulation

Management of infrastructure projects is becoming increasingly challenging due to inherent uncertainties. The most effeective way to deal with uncertainty is to collect supplementary information and knowledge. When expensive or infeasible, quantification of uncertainty may be performed using analytical or simulation techniques. The City of Edmonton, Canada has approximately 4600 km of sewer pipes in the combined, sanitary, and storm sewer local systems with uncertainty issues related to deterioration. The City has taken a proactive approach with respect to sewer rehabilitation, as it is more cost-effeective to repair a defective pipe prior to failure rather than after a collapse. This article demonstrates an approach for predicting the condition of a sewer pipe and the related cost of rehabilitation, given the limited data. Three models are described in this article that are developed to assist the City of Edmonton to effeectively plan maintenance expenditure. Each model uses a combination of rule-based simulation and probability analysis to assist in the planning of future expenditures for sewer maintenance, thereby producing an invaluable planning tool.     

填充了碳纳米管的连续纳米纤维的静电纺丝

<正>尽管在单壁碳纳米管(SWNTs)的合成和表征方面已经取得了重大进展,但还有一重大挑战,即寻找一条有效途径来接通纳米管及工程材料和结构之间的尺寸和性能的通道。为了将SWNT的超性能转化到中型和大型结构中,人们已经花费了很大精力来开发线性和平面SWNT组件。本文描述的静电     

Prevalence and characterization of Salmonella enterica serovar Weltevreden from imported seafood

During 2001-2005, 210 Salmonella enterica strains were isolated from seafood samples imported into US. Strains of S. enterica serovar Weltevreden were the most predominantly found among the 64 different serovars isolated. A total of 37 Salmonella Weltevreden isolates were characterized by pulsed-field gel electrophoresis (PFGE), plasmid profiles and antibiotic susceptibility to assess genetic diversity. Our results showed a low frequency of antibiotic resistance; 35 of the 37 isolates were sensitive to ampicillin, tetracycline, chloramphenicol, gentamicin, sulfisoxazole, streptomycin and kanamycin. Only two isolates, from samples originating in the Philippines and India, showed resistance to ampicillin and tetracycline and to streptomycin, sulfisoxazole and tetracycline, respectively. Of the 37 isolates, two isolates did not carry any plasmid and 35 isolates harbored several small and mega-plasmids. These isolates were differentiated into 10 distinct types based on plasmid profiles. Four different PFGE clusters were obtained with a genetic similarity of 66-76%. Four groups of isolates (formed by two or three isolates each) showed 100% similarity in the PFGE profiles. One of these groups included strains isolated in Vietnam in 2003, 2004 and 2005 from fish and shrimp. The other groups included strains isolated in Vietnam, Indonesia and Thailand in 2000, 2004 and 2005 from snail, shrimp and fish. Our findings show genetic diversity and temporal persistence of S. enterica serovar Weltevreden in recently monitored seafood imports.     

Microbiological survey of tofu sold in a rural Illinois county.

The purpose of this study was to determine the microbial status of tofu sold in a rural Illinois county and assess the factors contributing to the safety of tofu. Six brands of tofu from eight different stores (60 total samples) were purchased and analyzed for temperature, pH, total aerobic bacteria, and the presence of coliforms. Relationships between age, temperature, pH of tofu, and total aerobic bacteria were tested. An analysis of variance was also performed to test for differences in total bacterial counts among the brands. Mean aerobic bacterial counts ranged from 0 to 7.76 x 10(7) CFU/g. Fifty-five percent of the tofu tested fell within the excellent range for freshness as delineated by the standards developed by the Soyfoods Association of North America, 6.7% fell within the acceptable range, 6.7% within the marginal range, and 28% within the unacceptable range. Sixteen percent of the samples contained coliform bacteria. No significant correlation was found between variables, except pH with total aerobic bacterial counts (r = -0.51) and pH with eosin-methylene blue agar counts (r = -0.67). Most of the tofu was displayed at unsafe temperatures (>5 degrees C) for potentially hazardous foods. This study confirmed the concerns regarding safety of tofu sold in the grocery stores. Based on these results, special training on tofu storage and handling is recommended for grocery stores selling this food product.     

Synthesis,characterization, and cell viability of bifunctional medical-grade polyurethane nanofiber: Functionalization by bone inducing and bacteria ablating materials

There is an extensive possibility of improving characteristics of fibers used in hard tissue engineering, being hydrophobic and less osteoconductive, resulting in the dynamic growth of new tissues. The current work focuses on the fabrication of nanofibers incorporated with titanium dioxide (TiO₂) ''as osteoconductive'' and silver (Ag) ''as self-healing'' nanoparticles (NPs). The incorporation of AgNO₃ by in situ method not only helped to impart the antibacterial activity but also changed the contact angle from 81 ± 03° in the case of pristine nanofibers to 74 ± 03°, 61 ± 03°, 50 ± 08°, and 39 ± 1.1°, in the composite scaffolds containing 0.01, 0.03, 0.05, and 0.07 M of Ag salts. The incubation in simulated body fluid at 37°C to induce mineralization on nanofiber scaffolds indicated Ca and P crystals' formation. The antibacterial activity showed significantly more toxicity toward E. coli (8.3 ± 0.9 mm) than S. aureus (1.2 ± 0.1 mm). Biocompatibility studies using MTT assay on the pre-osteoblasts showed that both TiO₂ and Ag NPs present in the nanofibers are non-toxic to the bone-like cells. However, results show that a higher concentration of Ag NPs (i.e., 0.07 M) is toxic to cells growing. Finally, all the results suggest that the nanofiber scaffolds have considerable scope for future bone tissue engineering materials.