Segmentation of virus particle candidates in transmission electron microscopy images

In this paper, we present an automatic segmentation method that detects virus particles of various shapes in transmission electron microscopy images. The method is based on a statistical analysis of local neighbourhoods of all the pixels in the image followed by an object width discrimination and finally, for elongated objects, a border refinement step. It requires only one input parameter, the approximate width of the virus particles searched for. The proposed method is evaluated on a large number of viruses. It successfully segments viruses regardless of shape, from polyhedral to highly pleomorphic.     

Using a molten organic conducting material to infiltrate a nanoporous semiconductor film and its use in solid-state dye-sensitized solar cells

We describe a method to fill thin films of nanoporous TiO₂ with solid organic hole-conducting materials and demonstrate the procedure specifically for use in the preparation of dye-sensitized solar cells. Cross-sections of the films were investigated by scanning electron microscopy and it was observed that a hot molten organic material fills pores that are 10 μm below the surface of the film. We characterized the incident photon to current conversion efficiency properties of the solid TiO₂/organic dye/organic hole-conductor heterojunctions and the spectra show that the dye is still active after the melting process.     

Control of the Preferred Orientation in MFI Films Synthesized by Seeding

Single crystal silicon and quartz wafers were seeded with colloidal TPA-silicalite-1 crystals. Hydrothermal treatment of the seeded substrates was used to grow dense MFI films. The preferred orientation of the crystals constituting the films as a function of the amount and size of seeds, film thickness and hydrothermal treatment conditions was investigated. In thin films, most of the crystalline material was found to be oriented with the b-axes close to perpendicular to the substrate surface. In thick films, the a- or c-axes were close to perpendicular to the substrate surface depending on the conditions used for hydrothermal treatment. The seed size and amount was found to affect the rate of change in preferred orientation as a function of film thickness. A film growth mechanism which is able to explain the experimental results is proposed.     

Mutlilevel theory of team decision making: Decision performance in teams incorporating distributed expertise.

The purpose of this research was to develop and test a theory of decision-making performance for hierarchical teams with distributed expertise. This theory identifies 3 core team-level constructs (team informity, staff validity, and hierarchical sensitivity) and 3 constructs below the team level that are central to decision-making accuracy in hierarchical teams with distributed expertise. Two studies are presented to test the proposed theory. A total of 492 college students worked on a computerized command-and-control simulator. Results from these studies are discussed in light of the theory. Similarities and differences in results across the 2 studies are discussed, as are potential modifications of the theory considering the data. Finally, implications of the theory for applied team contexts are elaborated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective cytotoxicity of two rodent T cell lymphomas to rat yolk sac tumours involves a retroviral envelope protein expressed by the lymphoma

OBJECTIVE: To test a model for the study of inequalities in hospitalizations in the city of Ribeirao Preto (SP), understanding them to be due both to the social position of inpatients and also to health care policies in Brazil. MATERIAL AND METHOD: Using a hospital information system in existence for more than 25 years in the city of Ribeirao Preto-SP, 56.293 hospitalizations of municipal inhabitants occurring in some of the 12 general hospitals in 1993, were studied. Using the Brazilian occupancy classification for mortality, these inpatients were grouped on 6 occupational levels, as in the British classification: professional, intermediate, qualified non manual, qualified manual, partially qualified and unqualified. RESULTS AND CONCLUSIONS: Two-thirds of the inpatients had no place in the i.e. did not belong to the economically active population--and consisted of housewives, pensioners, children and students--and one third had some economic activity and thus belonged to the economically the active population. A close association was found between social strata and the classification of the hospital financing system into private, private group clinic and public health system patients. There were differences in hospital parameters as well as in morbidity patterns between these groups. The inequalities relating to average age, average age of hospital deaths, mean lengths of stay, hospital mortality, re-internment and frequency of diseases are discussed. This model allows the social position of the inpatient to be estimated using the hospital financing system, including also those patients with no economic activity, which covers the majority of the population. Social mechanisms created to compensate for inequalities in the welfare state do not cancel out the social differences.     

Accuracy decomposition and team decision making: Testing theoretical boundary conditions.

The purpose of this study was to examine the implications of accuracy decomposition (D. Gigone & R. Hastie, 1997) for team decision making. Specifically, the authors tested the generalizability of the multilevel theory of team decision making (J. R. Hollenbeck et al., 1995), across various components of accuracy. The authors also tested the generalizability of this theory across different levels of staff-member specialization. Results from a study with 420 individuals in 105 teams demonstrate that the validity of the multilevel theory generalizes across specialization levels but fails to generalize across different components of decision accuracy. The authors concluded that this theory is best conceptualized as a theory of achievement accuracy, rather than mean bias or variability bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automated feedback control of body temperature for small animalstudies with MR microscopy

A temperature control system consisting of a thermistor, signal processor, and computer algorithm was developed for magnetic resonance (MR) microscopy of small live animals. With control of body temperature within ±0.2°C of the set point, heart rate is stabilized and, in turn, repetition time (TR) during cardiac-gated studies is less variable. Thus, image quality and resolution are improved     

Measuring the progression of foreign-body reaction to silicone implants using in vivo MR microscopy

We used in vivo magnetic resonance (MR) microscopy to follow the growth of fibrous capsule as a foreign body reaction to silicone implants in rats. Anesthetized rats were imaged 1, 7, 14, and 28 days after silicone-coated MR imaging coils were sutured to their neck muscles. On the twenty-eighth day, rats were sacrificed and coils and adjacent tissues were removed en bloc and fixed in formalin, reimaged with MR, and sectioned for conventional histology. Three-dimensional (3-D) spin-echo [3DFT] acquisition gave in-plane resolution of 32 x 32 microns in vivo and 16 x 16 microns ex vivo. All MR images showed a diffuse band of elevated signal intensity between the silicone of the coil and adjacent tissue. The border of the hyperintense band was thin and not well defined at seven days post-implantation. From 7-28 days, the band showed relatively homogeneous signal intensity and its thickness increased 44% on the rectus muscle side and 78% on the subcutaneous side. The capsule thickness determined either by MR in vivo and ex vivo microscopy or conventional histology was not significantly different, and there was a significant correlation between thickness measurements among those methods. MR in vivo microscopy provides sufficient resolution and spatial information to serially evaluate the growth of the foreign body fibrous capsule over time, thus achieving greater accuracy and consistency in measurements.     

An assessment of the 1982 traffic fatality decrease

United States traffic fatalities dropped dramatically from 49,301 in 1981 to an estimated 43,721 in 1982. Fatalities are at their lowest level in 20 yr, and fatalities per mile of travel are the lowest ever recorded. A decrease of similar magnitude occurred only in 1974, when the oil crisis, the national 55 mph speed limit, and depressed economic conditions disrupted the nation's driving habits. In 1982 the potential explanations are more difficult to observe and test. This paper examines several factors which may have contributed to the 1982 changes, including alcohol programs, occupant restraint use, demographic shifts, economic conditions, and travel patterns. Each factor's effect is assessed, though available data do not permit precise quantification. Implications of these findings for 1983 and beyond are discussed.