Highly oriented star-like patterns observed on GaSe epilayers grown on Si(111)

Epitaxial lamellar gallium selenide (GaSe) semiconductors have been grown on trench-patterned silicon (Si) substrates by molecular beam epitaxy. An intriguing star-like patterned morphology was identified by atomic force microscopy on these epilayers. This non-trivial feature can be correlated with the accumulation of stacking faults of two concurrent epitaxial domains around self-oriented triangular pits developed earlier on the Si(111) surface by the chemical etching. Crystallographic considerations show how the stars can be formed.     

Relation of self-image to body size and weight loss attempts in black women: the CARDIA study. Coronary Artery Risk Development in Young Adults

It has been suggested that the prevalence of obesity in black women is high partly because self-image in black women is not strongly dependent on body size. To determine associations between self-image, body size, and dieting behavior among black women, the authors assessed an Appearance Evaluation Subscale (AES) score (range, 1-5), a Body Image Satisfaction (BIS) score (range, 2-11), and reported dieting behavior in a population-based sample of 1,143 black women aged 24-42 years from the fourth follow-up examination (1992-1993) of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Lower AES and BIS scores indicate poorer self-image and lower body size satisfaction, respectively. After adjustment for age, education, smoking, and physical activity, women in the lowest, middle, and highest tertiles of body mass index (weight (kg)/height (m)2) had mean AES scores of 3.7, 3.3, and 2.9, respectively (p < 0.001), and mean BIS scores of 7.8, 6.7, and 5.9, respectively (p < 0.001). After additional control for body mass index as a continuous variable, both AES and BIS scores were inversely related to ever dieting, current dieting, and previous weight loss of 10 pounds (4.5 kg) or more in all tertiles of body mass index. These results suggest that among black women, a higher body mass index is associated with poorer self-image and lower body size satisfaction and that these perceptions may be an avenue to promoting weight control.     

Characterization of semiconductor processing by Sn conversion electron Mössbauer spectroscopy

In this article we report on the use of ¹¹⁹Sn conversion electron Mössbauer spectroscopy to characterize several different steps of the semiconductor processing technology. The epitaxial regrowth of silicon preamorphized using ¹¹⁹Sn⁺ implantation by furnace-annealing and by rapid thermal processing, and the substitutionality and lattice location of implanted impurities in silicon are investigated. The physicochemical structure of the amorphous semiconductor GeSn thin films deposited by sputtering codeposition is also characterized and reported here. Finally, thin films of semiconductor SnO_x deposited by reactive sputtering are characterized after the different processing steps aiming to prepare films adequately for gas sensing.     

Comparison of projection algorithms used for the construction of maximum intensity projection images

OBJECTIVE: Four methods of producing maximum intensity projection (MIP) images were studied and compared. MATERIALS AND METHODS: Three of the projection methods differ in the interpolation kernel used for ray tracing. The interpolation kernels include nearest neighbor interpolation, linear interpolation, and cubic convolution interpolation. The fourth projection method is a voxel projection method that is not explicitly a ray-tracing technique. The four algorithms' performance was evaluated using a computer-generated model of a vessel and using real MR angiography data. The evaluation centered around how well an algorithm transferred an object's width to the projection plane. RESULTS: The voxel projection algorithm does not suffer from artifacts associated with the nearest neighbor algorithm. Also, a speed-up in the calculation of the projection is seen with the voxel projection method. Linear interpolation dramatically improves the transfer of width information from the 3D MRA data set over both nearest neighbor and voxel projection methods. Even though the cubic convolution interpolation kernel is theoretically superior to the linear kernel, it did not project widths more accurately than linear interpolation. A possible advantage to the nearest neighbor interpolation is that the size of small vessels tends to be exaggerated in the projection plane, thereby increasing their visibility. CONCLUSION: The results confirm that the way in which an MIP image is constructed has a dramatic effect on information contained in the projection. The construction method must be chosen with the knowledge that the clinical information in the 2D projections in general will be different from that contained in the original 3D data volume.     

A microcomputer-based pallet layout system to evaluate and improve storage space utilization

This paper discusses a microcomputer-based system used to maximize the storage space utilization for palletized materials. Pallet and carton sizes and stacking constraints for specific stock numbers are used to compute and select the best layout from several possible alternatives. The results, giving the simplest stable layout, are converted to graphic form and printed on a dot-matrix printer for use by Engineers and Warehouse personnel in evaluating and improving storage space utilization.     

Sound-induced seizures in serotonin 5-HT2c receptor mutant mice

OBJECTIVES: In previous University of California, San Diego (UCSD) studies, nocturnal illumination shortened menstrual cycles that were longer than 33 days. The studies reported here extend the previous findings, confining the illumination to the sleep period. DESIGN: Two light levels (235 to 250 lux and less than 1 lux) and 2 modes of light delivery (lighted sleep mask and bedside lamp) were tested. RESULTS: 235 to 250 lux treatment cycle lengths were significantly shorter than baseline, but not significantly shorter than the less than 1 lux treatment cycle lengths. Subjective reports of sleep disturbance were greater with the 235 to 250 lux treatment, but there was no significant difference in overall quality of sleep between the two light levels. CONCLUSIONS: The current data alone do not exclude spontaneous remission or suggestion, but our previous studies demonstrated significant contrasts between 235 to 250 lux and less than 1 lux light levels. This study suggests that treatment may be effective when confined to the sleep period, and that light masks, which do not disturb bed partners, may be used in place of bedside lamps.     

The importance of ray pathlengths when measuring objects in maximum intensity projection images

It is important to understand any process that affects medical data. Once the data have changed from the original form, one must consider the possibility that the information contained in the data has also changed. In general, false negative and false positive diagnoses caused by this post-processing must be minimized. Medical imaging is one area in which post-processing is commonly performed, but there is often little or no discussion of how these algorithms affect the data. This study uncovers some interesting properties of maximum intensity projection (MIP) algorithms which are commonly used in the post-processing of magnetic resonance (MR) and computed tomography (CT) angiographic data. The appearance of the width of vessels and the extent of malformations such as aneurysms is of interest to clinicians. This study will show how MIP algorithms interact with the shape of the object being projected. MIP's can make objects appear thinner in the projection than in the original data set and also alter the shape of the profile of the object seen in the original data. These effects have consequences for width-measuring algorithms which will be discussed. Each projected intensity is dependent upon the pathlength of the ray from which the projected pixel arises. The morphology (shape and intensity profile) of an object will change the pathlength that each ray experiences. This is termed the pathlength effect. In order to demonstrate the pathlength effect, simple computer models of an imaged vessel were created. Additionally, a static MR phantom verified that the derived equation for the projection-plane probability density function (pdf) predicts the projection-plane intensities well (R(2)=0.96). Finally, examples of projections through in vivo MR angiography and CT angiography data are presented.     

A robotic system for percutaneous renal access

PURPOSE: Percutaneous renal access can be challenging, particularly when the collecting system is not distended. Precise entry into a selected calyx facilitates subsequent percutaneous manipulations, but this skill requires extensive experience. In an attempt to improve accuracy while decreasing technical challenges, we developed a robotic system that automates the task of fluoroscopic image-guided percutaneous needle placement. MATERIALS AND METHODS: The prototype system consisted of a three degree-of-freedom robot with a needle injector end-effector. Imaging was provided by a biplanar fluoroscope. After correction of image distortion and fluoroscope calibration, robot to image-space registration was completed. To validate the system's ability to insert a needle into a calyx, ex vivo porcine kidneys suspended in agarose gel and distended with iodinated contrast solution were used as a model. In situ renal access tests with three 20 kg. pigs were performed. Access was confirmed by passing a flexible wire or aspirating iodinated contrast from the collecting system. RESULTS: The diameter of target calyces ranged from 3 to 7 mm. The in vitro accuracy of final needle tip positioning was 0.43 mm. In the ex vivo model, successful "one stick" access occurred on 10 of 12 attempts (83%). In situ access on the first attempt was successful for 6 of 12 target calyces (50%). Needle or tissue deflection accounted for each failure. CONCLUSION: The feasibility of a robotic system to assist in the percutaneous access of small and delicate renal calyces has been demonstrated. Additional work in reducing procedural steps and correcting for tissue deflection during needle passage is necessary to improve accuracy and to allow for clinical application.     

Deposition and characterization of CuInSe2 films for solar cells using an optimized chemical route

CuInSe₂ (CISe) thin films have been deposited on glass using successive ionic layer adsorption and reaction (SILAR). The as-deposited films are treated at 400 °C in argon atmosphere and etched in KCN solution to remove detrimental secondary phases. The preparation and temperature of the precursor solutions, the duration of the reaction cycles and the duration of the annealing stage have been optimized. The films have been characterized employing grazing incident X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive scanning spectroscopy. Relevant semiconductor parameters have been calculated. Photoelectrochemical tests confirm p-type conduction. The films are crystalline and the stoichiometry can be improved by renewing the precursor solution after completing half of the cycles, annealing for 90 min and later etching in KCN. The quality of the material seems to be promising for application in solar cell devices.