Structure of incommensurate gold sulfide monolayer on Au(111)

We develop an atomic-scale model for an ordered incommensurate gold sulfide (AuS) adlayer which has previously been demonstrated to exist on the Au(111) surface, following sulfur deposition and annealing to 450 K. Our model reproduces experimental scanning tunneling microscopy images. Using state-of-the-art Wannier-function-based techniques, we analyze the nature of bonding in this structure and provide an interpretation of the unusual stoichiometry of the gold sulfide layer. The proposed structure and its chemistry have implications for related S-Au interfaces, as in those involved in self-assembled monolayers of thiols on Au substrates

Dislocation nucleation in bcc Ta single crystals studied by nanoindentation

The study of dislocation nucleation in closed-packed metals by nanoindentation has recently attracted much interest. Here, we address the peculiarities of the incipient plasticity in body centered cubic (bcc) metals using low index Ta single-crystals as a model system. The combination of nanoindentation with high-resolution atomic force microscopy provides us with experimental atomic-scale information on the process of dislocation nucleation and multiplication. Our results reveal a unique deformation behavior of bcc Ta at the onset of plasticity which is distinctly different from that of closed-packed metals. Most noticeable, we observe only one rather than a sequence of discontinuities in the load-displacement curves. This and other differences are discussed in context of the characteristic plastic deformation behavior of bcc metals

Massachusetts Adult Tobacco Survey: Tobacco Use and Attitudes After Seven Years of The Massachusetts Tobacco Control Program, Technical Report & Tables 1993 — 2000

The Massachusetts Tobacco Control Program was launched in October of 1993. At that time, the Center for Survey Research conducted the Massachusetts Tobacco Survey (MTS), a comprehensive survey of adults and teens living in Massachusetts. The purpose of the survey was to collect baseline data on the prevalence of tobacco use among adults and teens in the Commonwealth and on issues related to the likelihood of smoking cessation or initiation. The survey also assessed the prevalence of restrictive smoking policies, and attitudes about tobacco control measures. The baseline data serve as a standard against which the impact of various programs sponsored by the Department of Public Health can be assessed. Technical details about the MTS and reports of the results are available from the Massachusetts Department of Public Health. In January, 1995 the Department of Public Health contracted with the Center for Survey Research to carry out a second survey monitoring tobacco use and related attitudes and behaviors among adults in the Commonwealth. This second survey, known as the Massachusetts Adult Tobacco Survey (MATS), has been carried out monthly since March of 1995. Data are aggregated at the end of each calendar year. MATS is similar to the MTS in that initial screening interviews are carried out with a household member who provides demographic and smoking status information about other adults in the household. One member of the household is then randomly selected for extended interview. The annual sample for this survey is smaller than that used for the MTS and does not include teens. It also differs from the MTS in that smokers were not over-sampled, nor were members of minority groups. The sample was geographically stratified as was the MTS. (More details on the sampling design are presented in Chapter I.) Technical Reports are available for the 1993 MTS survey, and for the 1995 through 1999 MATS surveys. Please refer to those reports for descriptions of the respective surveys and a more general discussion of the use of the telephone survey for data collection. This report presents methodological details of the 2000 MATS. It contains an appendix of tables of major results for data collected each year. Nontechnical reports describing the major results are available from the Massachusetts Department of Public Health

Selective Thermal Reduction of Single-layer MoO3 nanostructures on Au(111)

MoO{sub 3} is an interesting oxide prototype because its catalytic activity is sensitive to the presence and nature of defects. In this work, we demonstrate that we can control the number of defects in single-layer MoO{sub 3} nanostructures grown on Au(111) by a simple thermal reduction treatment. X-ray photoelectron spectroscopy demonstrates the formation of Mo{sup 5+} species and oxygen vacancies during annealing at 650 K. The percentage of Mo{sup 5+} increases with the duration of annealing, until a stable composition containing 50% Mo{sup 6+} and 50% Mo{sup 5+} is obtained. Surprisingly, the formation of lower oxidation states such as Mo{sup 4+} was not observed. The reduced MoO{sub x} islands remain one layer high, based on scanning tunneling microscope (STM) images. The two-dimensional nature of the reduced oxide nanocrystals may be due to a large barrier for structural reorganization and, thus, may account for the absence of Mo oxidation states lower than +5. Based on scanning tunneling microscopy images and density functional calculations, we propose that the formation of Mo{sup 5+} ions during annealing is not associated with formation of oxygen point defects, but can be attributed to the formation of extended one-dimensional shear defects. These reduced structures are useful for studying the dependence of reactivity on defect type, and present exciting possibilities for chemical sensors and other applications

Breaking the Screen: Interaction Across Touchscreen Boundaries in Virtual Reality for Mobile Knowledge Workers.

Virtual Reality (VR) has the potential to transform knowledge work. One advantage of VR knowledge work is that it allows extending 2D displays into the third dimension, enabling new operations, such as selecting overlapping objects or displaying additional layers of information. On the other hand, mobile knowledge workers often work on established mobile devices, such as tablets, limiting interaction with those devices to a small input space. This challenge of a constrained input space is intensified in situations when VR knowledge work is situated in cramped environments, such as airplanes and touchdown spaces. In this paper, we investigate the feasibility of interacting jointly between an immersive VR head-mounted display and a tablet within the context of knowledge work. Specifically, we 1) design, implement and study how to interact with information that reaches beyond a single physical touchscreen in VR; 2) design and evaluate a set of interaction concepts; and 3) build example applications and gather user feedback on those applications.Comment: 10 pages, 8 figures, ISMAR 202

The ePetri dish, an on-chip cell imaging platform based on subpixel perspective sweeping microscopy (SPSM)

We report a chip-scale lensless wide-field-of-view microscopy imaging technique, subpixel perspective sweeping microscopy, which can render microscopy images of growing or confluent cell cultures autonomously. We demonstrate that this technology can be used to build smart Petri dish platforms, termed ePetri, for cell culture experiments. This technique leverages the recent broad and cheap availability of high performance image sensor chips to provide a low-cost and automated microscopy solution. Unlike the two major classes of lensless microscopy methods, optofluidic microscopy and digital in-line holography microscopy, this new approach is fully capable of working with cell cultures or any samples in which cells may be contiguously connected. With our prototype, we demonstrate the ability to image samples of area 6 mm × 4 mm at 660-nm resolution. As a further demonstration, we showed that the method can be applied to image color stained cell culture sample and to image and track cell culture growth directly within an incubator. Finally, we showed that this method can track embryonic stem cell differentiations over the entire sensor surface. Smart Petri dish based on this technology can significantly streamline and improve cell culture experiments by cutting down on human labor and contamination risks

Snus use and rejection in the USA

OBJECTIVE: To determine whether snus might become a strategy for reducing the harm associated with cigarette smoking in the USA as appears to be the case in Sweden, we examined receptivity to snus use in two cities with the greatest exposure to the major brands. METHODS: A dual frame, telephone survey and a brief mail survey were conducted in 2011 and 2012 in Indianapolis, Indiana and Dallas/Fort Worth Texas. Over 5000 adults completed surveys. Trial, ever use, current use and reasons for using or quitting snus after trial were measured. RESULTS: Among male smokers, 29.9% had ever tried snus (CI 22.7 to 38.1) and 4.2% were current users (CI 1.6 to 10.7). Among female smokers, 8.5% ever tried snus (CI 4.4 to 15.7) and current use was unknown. Current use was virtually absent among former smokers and never smokers. A major predictor of any level of snus use was current use of conventional smokeless tobacco. Those who tried and gave up snus cited curiosity (41.3%) and the fact that it was available at low or no cost (30%) as reasons for trial; reasons for not continuing included preferring another form of tobacco (75.1%) and disliking the mouth feel (34.6%). Almost all current snus users indicated that they were trying to cut down on cigarettes, but few (3.9%) were using it to quit smoking entirely. CONCLUSIONS: The low rate of adoption of snus suggests that neither the hopes nor the fears surrounding this new product are likely to be realised in the USA with the current marketing patterns

Ultra-low-density digitally architected carbon with a strutted tube-in-tube structure

Porous materials with engineered stretching-dominated lattice designs, which offer attractive mechanical properties with ultra-light weight and large surface area for wide-ranging applications, have recently achieved near-ideal linear scaling between stiffness and density. Here, rather than optimizing the microlattice topology, we explore a different approach to strengthen low-density structural materials by designing tube-in-tube beam structures. We develop a process to transform fully dense, three-dimensional printed polymeric beams into graphitic carbon hollow tube-in-tube sandwich morphologies, where, similar to grass stems, the inner and outer tubes are connected through a network of struts. Compression tests and computational modelling show that this change in beam morphology dramatically slows down the decrease in stiffness with decreasing density. In situ pillar compression experiments further demonstrate large deformation recovery after 30-50% compression and high specific damping merit index. Our strutted tube-in-tube design opens up the space and realizes highly desirable high modulus-low density and high modulus-high damping material structures

The impact of televised tobacco control advertising content on campaign recall: evidence from the International Tobacco Control (ITC) United Kingdom Survey

BACKGROUND: Although there is some evidence to support an association between exposure to televised tobacco control campaigns and recall among youth, little research has been conducted among adults. In addition, no previous work has directly compared the impact of different types of emotive campaign content. The present study examined the impact of increased exposure to tobacco control advertising with different types of emotive content on rates and durations of self-reported recall. METHODS: Data on recall of televised campaigns from 1,968 adult smokers residing in England through four waves of the International Tobacco Control (ITC) United Kingdom Survey from 2005 to 2009 were merged with estimates of per capita exposure to government-run televised tobacco control advertising (measured in GRPs, or Gross Rating Points), which were categorised as either “positive” or “negative” according to their emotional content. RESULTS: Increased overall campaign exposure was found to significantly increase probability of recall. For every additional 1,000 GRPs of per capita exposure to negative emotive campaigns in the six months prior to survey, there was a 41% increase in likelihood of recall (OR = 1.41, 95% CI: 1.24–1.61), while positive campaigns had no significant effect. Increased exposure to negative campaigns in both the 1–3 months and 4–6 month periods before survey was positively associated with recall. CONCLUSIONS: Increased per capita exposure to negative emotive campaigns had a greater effect on campaign recall than positive campaigns, and was positively associated with increased recall even when the exposure had occurred more than three months previously