Fabrication of micro optics on coreless fiber segments

Fabrication of micro optics for fiber optics applications is a challenge due to their size and the issues associated with alignment of the optics to single-mode fibers. This study summarizes a method for fabricating diffractive optical elements on the ends of coreless fiber segments for passive alignment to single-mode fibers. Results are presented for passively aligned diffractive lens elements used for both collimation and beam shaping.     

Differences in the level of expression of class I major histocompatibility complex proteins on thymic epithelial and dendritic cells influence the decision of immature thymocytes between positive and negative selection

Both positive and negative selection of immature T cells rely on engagement of their antigen-specific receptors (TCR) by peptide in association with proteins encoded in the major histocompatibility complex (MHC) protein. The decision made between these two outcomes seems to be determined by the number of TCR engaged by peptide-MHC complexes. It has been unclear how such a mechanism can be reconciled with evidence that positive and negative selection occur in different thymic compartments and are mediated by different antigen-presenting cells (APCs). In this study we demonstrate that the level of class I MHC protein is 10-fold higher on thymic dendritic cells, which mediate the negative selection of immature T cells, than on thymic epithelial cells, which mediate for positive selection. We also demonstrate that as little as a 3-fold increase in the level of a particular cognate peptide-MHC ligand is sufficient to result in negative rather than positive selection. The results suggest that quantitative differences in the level of expression of class I MHC proteins on thymic epithelial and dendritic cells contribute to the opposing roles these cells play in forming the repertoire of mature class I MHC restricted (CD8+) T cells.     

Transient response of shells with internally attached structures

Equations of motion are derived for the transient response, to a shock wave, of a submerged shell with internal structures. A substructuring procedure, which does not require calculation of a system stiffness matrix, is employed to obtain these equations in a general manner for arbitrary internal structures approximated by finite elements.     

Interaction of individual differences with visual and verbal elaboration instructions.

Investigated (a) to what extent the typical effects of elaboration instructions and the imagery characteristics of verbal material would obtain for foreign-language/English word pairs and (b) to what extent individual differences would moderate these effects. To explore these issues, verbal fluency, visualization ability, and instructions were factorially varied between Ss, and the imagery characteristics of the response terms were varied within Ss. 48 university students were selected for participation in the experiment on the basis of their performance on psychometric tests. The result of most interest was the crossover interaction between verbal fluency and elaboration instructions. Results are discussed in terms of Aptitude?×?Treatment interactions and the importance of individual differences in decisions regarding instructional methods. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Jaundice associated with polycystic liver disease. Relief by surgical decompression of the cysts

Jaundice is an unusual feature of polycystic liver disease. In a 46-year-old woman with polycystic liver disease and jaundice, the bilirubin level was 42.0 mg/100 ml. Because of the rapid rise in bilirubin level, relief of supposed obstruction of intrahepatic bile ducts was attempted by unroofing the hepatic cysts. Following operation the bilirubin level returned to normal, and the patient has remained well since.     

Dynamic elastic-plastic response of a containment vessel to fluid pressure pulses

The dynamic analysis of the wall of a fluid-filled unstiffened nuclear containment vessel, to the fluid pressure exerted on it when the relief valve discharge piping is cleared, is extended into the plastic range using two versions of an elastic-plastic shell theory.     

The role of awakening cortisol and psychological distress in diurnal variations in affect: A day reconstruction study.

People often feel unhappy in the morning but better later in the day, and this pattern may be amplified in the distressed. Past work suggests that one function of cortisol is to energize people in the morning. In a study of 174 students, we tested to see whether daily affect patterns, psychological distress, and awakening cortisol levels were interlinked. Affect levels were assessed using the Day Reconstruction Method and psychological distress was measured using the Depression Anxiety Stress Scales. On average, positive affect increased markedly in a linear pattern across the day, whereas negative affect decreased linearly. For the highly distressed, this pattern was stronger for positive affect. Lower than average morning cortisol, as assessed by two saliva samples at waking and two samples 30 min after waking, predicted a clear increasing pattern of positive affect throughout the day. When we examined the interlinkages between affect patterns, distress, and cortisol, our results showed that a pronounced linear increase in positive affect from morning through to evening occurred chiefly among distressed people with below average cortisol levels upon awakening. Psychological distress, although not strongly associated with morning cortisol levels, does appear to interact with cortisol levels to profoundly influence affect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Near-infrared luminescence of cadmium pigments: in situ identification and mapping in paintings

A comprehensive study of the luminescence properties of cadmium pigments was undertaken to determine whether these properties could be used for in situ identification and mapping of the pigments in paintings. Cadmium pigments are semiconductors that show band edge luminescence in the visible range and deep trap luminescence in the red/infrared range. Emission maxima, quantum yields, and excitation spectra from the band edge and deep trap emissions were studied for sixty commercial cadmium pigments that span the color range from yellow to red (reflectance transition 470 to 660 nm). For paints containing cadmium pigments, luminescence from deep traps was more readily observable than that from the band edge, although the yield varied widely from zero to around 4.5%. Optimal excitation for emission is found to be in the visible for both pigments in powder form and mixed with a medium. The maxima of the deep trap emission shift with the band gap energy, providing a potentially useful way to assign pigment type even when used in pigment mixtures. The usefulness of the results of the study on mockups was demonstrated by the mapping of cadmium pigments of different hues with the aid of calibrated luminescence imaging spectroscopy in a painting by Edward Steichen, entitled Study for 'Le Tournesol' (1920). Analysis of the luminescence image cube reveals at least six unique spectral components, associated with emission from white pigments, paint binder, and cadmium red and yellow pigments. The results were compared with those from X-ray fluorescence spectrometry (XRF) and fiber-optic reflection spectroscopy (FORS) and the results obtained on paint samples containing cadmium pigments. These results show that, when present, the emission from traps can be used as an analytical tool to identify cadmium pigments, to distinguish among cadmium sulfide, cadmium zinc sulfide, and cadmium sulfoselenide, and to map cadmium pigments, even in mixtures.     

Calculation of error probabilities for distance-invariant nonlinear error control codes

Expressions are given for the distance distribution of some nonlinear codes which enable error probabilities to be calculated using methods commonly associated with linear error control codes.<>