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At least 343 records · Page 19Linked to original sources
PubMed2006

Nonpolarizing beam splitter designed by frustrated total internal reflection inside a glass cube.

A method for the design of an all-dielectric nonpolarizing prism beam splitter utilizing the principle of frustrated total internal reflection is reported. The nonpolarizing condition for a prism beam splitter is discussed, and some single layer design examples are elaborated. The concept can be applied to a wide range of wavelengths and arbitrary transmittance values, and with the help of a computer design program examples of 400-700 nm, T(p)=T(s)=0.5+/-0.01, with incident angles of 45 degrees and 62 degrees are given. In addition, the sensitivity and application of the design are also discussed.

Journal Article↗
PubMed2006

Phase shifts in frustrated total internal reflection and optical tunneling by an embedded low-index thin film.

Simple and explicit expressions for the phase shifts that p- and s-polarized light experience in frustrated total internal reflection (FTIR) and optical tunneling by an embedded low-index thin film are obtained. The differential phase shifts in reflection and transmission deltar, deltat are found to be identical, and the associated ellipsometric parameters psir, psit are governed by a simple relation, independent of film thickness. When the Fresnel interface reflection phase shifts for the p and s polarizations or their average are quarter-wave, the corresponding overall reflection phase shifts introduced by the embedded layer are also quarter-wave for all values of film thickness. In the limit of zero film thickness (i.e., for an ultrathin embedded layer), the reflection phase shifts are also quarter-wave independent of polarization (p or s) or angle of incidence (except at grazing incidence). Finally, variable-angle FTIR ellipsometry is shown to be a sensitive technique for measuring the thickness of thin uniform air gaps between transparent bulk media.

Journal Article↗
PubMed2005

Apparent causality paradox in frustrated Gires-Tournois interferometers.

Negative group delay times upon total reflection from frustrated Gires-Tournois interferometers seem to violate causality. Contrary to what has been recently argued in the literature, I show with the example of total light reflection upon an ideal nonabsorbing plasma that adding the time associated with the Goos-Hänchen shift does not solve the paradox, which remains open.

Journal Article↗
PubMed2005

Resonant tunneling in frustrated total internal reflection.

Anomalous light transmission and resonant tunneling in frustrated total internal reflection (FTIR) are theoretically predicted to occur at periodically curved interfaces. For a low-contrast index and for grazing incidence, it is shown that FTIR resonant tunneling provides an optical realization of field-induced barrier transparency in quantum tunneling.

Journal Article↗
PubMed2004

Health maintenance organization (HMO) performance and consumer complaints: an empirical study of frustrating HMO activities.

Growing public interest in the operations of managed care plans has fueled a variety of activities to collect and analyze their performance. These activities include studies of financial performance, analysis of enrollment decisions, and, more recently, the development of systems for measuring healthcare quality to improve accountability to consumers. In this study, the authors focus on the activities of managed care plans that may frustrate patients and providers and, subsequently, motivate patients to file complaints. Using data from three sources, they evaluate the relationships between complaints against managed care plans and two metrics of performance: (a) the financial performance of the plan, and (b) the quality of care provided. Their findings indicate that complaints against health maintenance organizations are significantly related to the plans' levels of quality and to actions that may impede access to care.

Empirical Research↗
PubMed1999

User satisfaction and frustration with a handheld, pen-based guideline implementation system for asthma.

OBJECTIVE: To evaluate clinicians' satisfaction and frustrations with the use of a handheld computer system that implements a guideline for management of childhood asthma exacerbations. SETTING: Nine primary-care pediatric practices. DESIGN: Survey component of a randomized, prospective before-after trial. INTERVENTION: Newton MessagePad outfitted with custom software (called "AsthMonitor") that assists in documentation of clinical findings and provides guideline-based recommendations. RESULTS: Overall, 3 users gave strongly positive global ratings while 6 users were neutral. The majority used the documentation functions concurrently with care. Except for recommendations to administer oxygen (which were unsupported by evidence), users found the recommendations appropriate and appreciated the reminders. Seven of 9 participants believed it took more time to document with AsthMonitor. CONCLUSIONS: Handheld computers are acceptable to some office-based practitioners to provide guideline-based advice within the context of the clinical encounter.

Asthma↗
PubMed1999

A data base of minimally frustrated alpha helical segments extracted from proteins according to an entropy criterion.

A data base of minimally frustrated alpha helical segments is defined by filtering a set comprising 822 non redundant proteins, which contain 4783 alpha helical structures. The data base definition is performed using a neural network-based alpha helix predictor, whose outputs are rated according to an entropy criterion. A comparison with the presently available experimental results indicates that a subset of the data base contains the initiation sites of protein folding experimentally detected and also protein fragments which fold into stable isolated alpha helices. This suggests the usage of the data base (and/or of the predictor) to highlight patterns which govern the stability of alpha helices in proteins and the helical behavior of isolated protein fragments.

Algorithms↗
PubMed1991

Composition of proteoglycan fragments from hyaline cartilage produced by granulocytes in a model of frustrated phagocytosis.

An in vitro model of frustrated phagocytosis was developed in which granulocytes interact with well-defined slices of hyaline cartilage. The composition of the purified proteoglycan fragments released from the cartilage slices by N-formyl-methionyl-leucyl-phenylalanine-stimulated granulocytes was studied after 30, 60 and 90 min incubation time. It was shown that the proteoglycan fragments do not change their composition during incubation. The only change observed during incubation was an increase in the quantity of the fragments. The protein content of the proteoglycan fragments is 7.0-8.6%, corresponding to a peptide chain of 24-28 amino acids, and the relative molecular mass of the total fragment is Mr = 37,600-39,200. On average, each proteoglycan fragment contains two chondroitin sulphate chains (Mr = 22,000-22,400), every fourth fragment contains a keratan sulphate chain (Mr = 7000-7200) and every seventh to eighth contains an O-glycosidic oligosaccharide, whereas no N-glycosidic oligosaccharide could be detected. The results of the disaccharide analysis show that the galactosaminoglycan chains contain 76.2-83.6% chondroitin 4-sulphate, 12.9-19.4% chondroitin 6-sulphate, 3.5-3.8% chondroitin and no dermatan sulphate. Since composition and relative molecular mass of the chondroitin sulphate and keratan sulphate chains from the proteoglycan fragments resemble those of native proteoglycans, the conclusion may be drawn that the degeneration of the proteoglycans occurs by proteases that attack preferably the chondroitin sulphate-rich region of the core protein. This is the first inflammation model of joint destruction, which demonstrates the elution of soluble specific proteoglycan degradation products of defined size.

Amino Acids↗
PubMed1989

"Medically unnecessary" letters create frustrating puzzles.

Medicare's "medically unnecessary" letters are frustrating puzzles to the many Texas physicians who receive them. While the letters question the medical necessity of care, they provide physicians with no basis for understanding and responding to that allegation. Medicare uses computerized screens to review claims, and it is those screens that are primarily responsible for the generation of "medically unnecessary" letters. The accompanying list of Medicare review screens provides a general clarification of what Medicare is looking for in the review process. The word "general" is an important qualification: there is no guarantee that a physician will be able to identify from the list the particular screen that has caused Medicare to request more information about a particular claim. But the list will help the practitioner in understanding what Medicare sees as the boundaries of customary medical practice and, in some instances, will help the physician respond to Medicare's request for additional information. With that broad introduction Texas Medicine presents the following guide to Medicare's claims screening criteria. It was prepared by the Texas Medical Association's Division of Medical Economics based on materials published by Medicare.

Health Services↗
PubMed1989

Rapid fragmentation and reorganization of Golgi membranes during frustrated phagocytosis of immobile immune complexes by macrophages.

The authors have observed the rapid reorganization of the cellular membranes of macrophages during Fc receptor-mediated frustrated phagocytosis of immune complex-coated surfaces. As the macrophages spread, large, clear basal vacuoles and anastamosing tubules were formed, occasionally contiguous with the adherent surface. Coated vesicles also were observed. This process was accompanied by a rapid reorganization of the Golgi complex region of the macrophages, which was observed using trimetaphosphatase histochemistry and an antibody to a Golgi membrane antigen as markers. On contact of the macrophages with the immune complexes, the Golgi complexes, which were tightly clustered around the centrioles, dispersed into vesicles and reorganized near the basal surface. The Golgi cisternae swelled, fragmented, and decreased in number. Golgi membrane antigen was found in the large basal vacuoles and also associated with the adherent basal surface of the macrophages. This indicates that the Golgi complexes were reorganized, in part, by a direct recruitment of their membranes to the increasing basal surface area of the spreading macrophages. The changes in the structure of the Golgi complexes were reversible; by 2 hours, the complexes had recovered their normal organization, with an accompanying decrease in the number of large basal vacuoles. These data suggest that the dynamic interrelationship among the Golgi membranes, intracellular vacuoles, and the plasma membrane can be perturbed by membrane spreading on a nonphagocytosable surface.

Animals↗
PubMed1987

Expression of HLA-DR, DQ and DP antigens and interleukin-2 receptor on synovial fluid T lymphocyte subsets in rheumatoid arthritis: evidence for "frustrated" activation.

Synovial fluid and peripheral blood T lymphocytes were examined from 10 patients with rheumatoid arthritis and 2 controls. T lymphocytes from inflammatory fluids were activated as shown by their increased size and expression of class II MHC antigens. Of the T cells, 60% were DR positive, 19% DP positive and 29% DQ positive. More Leu 2a than Leu 3a cells were HLA-DR positive. In contrast, few T cells expressed Tac. We conclude that T cell activation is taking place but is incomplete or "frustrated".

Adult↗
PubMed1988

How financial barriers can frustrate good arthritis care.

Current insurance practices discriminate against the arthritis patient who does not require acute-level care. Such practices inadequately deal with the financial barriers to the procurement of the health care services that are effective in relieving pain and increasing mobility and quality of life. The result often is frustration for both the patient and the physician.

Aged↗
PubMedDate not supplied

[Study of animal cell adhesion to glass by means of the frustrated total internal reflection method].

The method for studying the adhesion of mammalian cells to glass in vivo is presented. It is based on the effect of frustrated total reflection. It permits one to measure the index of refraction of hydroplasma situated near the site of cell-glass contact, to evaluate the distance between glass surface and cell surface membrane and to study the kinetics of flattening of the cell surface facing the glass.

Animals↗
PubMedDate not supplied

[The mental effects of chronic venous disease. Assessment by means of the Machover human figure test, Cattel anxiety test and Rosenzweig frustration test].

On the basis of routine clinical observations of mental stress, mainly of anxiety and depressive type, in the everyday treatment of chronic vascular disease, an attempt has been made to obtain a more strictly scientific assessment in relation to age, profession, admittance to hospital, degree of invalidity and immobility, etc. of two groups of patients with similar characteristics, one with chronic phlebopathy and a control group suffering from traumas of the lower extremities and their sequelae. Following intensive, highly informative conversations, the evaluation was made by means of the Machover human figure test which showed greater aggressiveness among the phlebopathy patients than the controls, the Cattel anxiety test (I.P.A.T.) which showed a marked prevalence of concealed anxiety in phlebopathy patients, and the Rosenzweig frustration test which revealed no significant differences between the groups. The data obtained were evaluated by statistical analysis with the Student test and Pearson's x test and results are reported.

Aged↗
PubMed1996

Frustrated residents worry as they look toward an uncertain future.

Frustrated, disheartened and angry that most provinces have introduced disincentive measures that target young physicians, today's residents are discouraged and uncertain about their future. Not only will the medical profession lose because of this situation, the residents say, but so will patients who are deprived of new ideas and physicians with the most current training. Nancy Robb examines the mood of the country's physicians-in-waiting.

Attitude of Health Personnel↗
PubMed1997

Women who return to abusive relationships: a frustration for the critical care nurse.

Nurses caring for abused women become frustrated and concerned when their patients return to the violent relationship. This disconcerted feeling can hinder the care nurses render to these women, subsequently leaving the victim powerless. Understanding this phenomenon can improve patient care, increase the image of women and, ultimately, help banish violence against women.

Attitude of Health Personnel↗
PubMed1997

Frustrated wants and entitlements: fundamental components of CRNA job satisfaction.

A comparative study was conducted examining CRNA feelings of deprivation or resentment as they relate to their job satisfaction. Deprivation is described in Faye Crosby's Theory of Relative Deprivation (1976), which posits that six psychological preconditions (wanting, comparison other, deserving, past expectations, future expectations, and lack of self-blame) have an impact on individual perceptions and can influence job satisfaction. Relative deprivation is defined as a sense of grievance or feeling of resentment that one has been unjustly deprived of some desired thing. It is also sometimes referred to as the discrepancy between one's legitimate expectations and one's actual situation. The three hypotheses examined compare the influence of the six Crosby preconditions of relative deprivation and the three background variables of gender, education, and individual job autonomy on CRNA-felt deprivation. Results from three-way analysis of variance indicated that of the three background variables, only degree of autonomy was found to be significant in explaining felt deprivation. That is, irrespective of gender or educational level, CRNAs reporting higher degrees of job autonomy had lower feelings of deprivation or resentment about their jobs than did individuals reporting limited job autonomy. Degree of autonomy, thus being the key background determinant of CRNA-felt deprivation (F = 14.609, P < .01). Further analysis employing multiple regression revealed that when both the background and the Crosby psychological variables were examined together, the explained variance in deprivation was dramatically increased by the psychological variables far in excess of the background variables. The two psychological variables of wanting and deserving were found as most significant in explaining CRNA felt deprivation. Results indicate the importance of CRNA frustrated wants (wanting) and CRNA perceived entitlements (deserving) as key factors contributing to CRNA job satisfaction above and beyond the three background variables studied.

Adult↗