Evolution of length scales and statistics of Richtmyer-Meshkov instability from direct numerical simulations.

In this study we present direct numerical simulation results of the Richtmyer-Meshkov instability (RMI) initiated by Ma=1.05,Ma=1.2, and Ma=1.5 shock waves interacting with a perturbed planar interface between air and SF(6). At the lowest shock Mach number the fluids slowly mix due to viscous diffusion, whereas at the highest shock Mach number the mixing zone becomes turbulent. When a minimum critical Taylor microscale Reynolds number is exceeded, an inertial range spectrum emerges, providing further evidence of transition to turbulence. The scales of turbulent motion, i.e., the Kolmogorov length scale, the Taylor microscale, and the integral length, scale are presented. The separation of these scales is found to increase as the Reynolds number is increased. Turbulence statistics, i.e., the probability density functions of the velocity and its longitudinal and transverse derivatives, show a self-similar decay and thus that turbulence evolving from RMI is not fundamentally different from isotropic turbulence, though nominally being only isotropic and homogeneous in the transverse directions.

Numerical simulation of tethered DNA in shear flow.

The behavior of tethered DNA in shear flow is investigated numerically by the smoothed dissipative particle dynamics (SDPD) method. Unlike numerical methods used in previous studies, SDPD models the solvent explicitly, takes into account the fully coupled hydrodynamic interactions and is free of the numerical artifact of wall sticking. Based on numerical simulations the static and dynamic properties of a tethered DNA is studied both qualitatively and quantitatively. The observed properties are in general agreement with previous experimental, numerical and theoretical work. Furthermore, the cyclic-motion phenomenon is studied by power spectrum density and cross-correlation function analysis, which suggest that there is only a very weak coherent motion of tethered DNA for a characteristic timescale larger than the relaxation time. Cyclic motion is more likely relevant as an isolated event than a typical mode of DNA motion.

The retinal ciliopathies.

While the functions of many of the proteins located in or associated with the photoreceptor cilia are poorly understood, disruption of the function of these proteins may result in a wide variety of phenotypes ranging from isolated retinal degeneration to more pleiotropic phenotypes. Systemic findings include neurosensory hearing loss, developmental delay, situs-inversus, infertility, disorders of limb and digit development, obesity, kidney disease, liver disease, and respiratory disease. The concept of "retinal ciliopathies" brings to attention the importance of further molecular analysis of this organelle as well as provides a potential common target for therapies for these disorders. The retinal ciliopathies include retinitis pigmentosa, macular degeneration, cone-dystrophy, cone-rod dystrophy, Leber congenital amaurosis, as well as retinal degenerations associated with Usher syndrome, primary ciliary dyskinesia, Senior-Loken syndrome, Joubert syndrome, Bardet-Biedl syndrome, Laurence-Moon syndrome, McKusick-Kaufman syndrome, and Biemond syndrome. Mutations for these disorders have been found in retinitis pigmentosa-1 (RP1), retinitis pigmentosa GTPase regulator (RPGR), retinitis pigmentosa GTPase regulator interacting protein (RPGR-IP), as well as the Usher, Bardet-Biedl, and nephronophthisis genes. Other systemic disorders associated with retinal degenerations that may also involve ciliary abnormalities include: Alstrom, Edwards-Sethi, Ellis-van Creveld, Jeune, Meckel-Gruber, Orofaciodigital Type 9, and Gurrieri syndromes. Understanding these conditions as ciliopathies may help the ophthalmologist to recognize associations between seemingly unrelated diseases and have a high degree of suspicion that a systemic finding may be present.

Bardet-Biedl Syndrome in an African-American patient: should the diagnostic criteria be expanded to include hydrometrocolpos?

Bardet-Biedl Syndrome (BBS) is a multisystemic disorder diagnosed on the basis of a combination of primary and secondary clinical features that include retinal dystrophy, obesity, polydactyly, cognitive dysfunction, and renal malformations. We report a unique case of BBS in a 13-year old girl of African-American descent who presented with retinitis pigmentosa, obesity, polydactyly, learning disabilities, precocious puberty, hypertension, renal cysts, and Hirschprung disease. Further evaluation revealed a history of precocious puberty, which is antithetical to the common manifestations of BBS, while neuroimaging was suggestive of periventricular leukomalacia and neuro-electrophysiologic studies revealed diffuse cerebral disturbance, which may contribute to her neurological abnormalities. The patient was also diagnosed with hydrometrocolpos, a finding typical of McKusick-Kaufman Syndrome (MKKS) but infrequent in other disorders. This observation, together with recent findings in some mouse models of BBS, raises the question of whether hydrometrocolpos should be considered as an additional diagnostic criterion for BBS to be used in females in parallel to the criterion of hypogonadism in males, thereby improving diagnostic sensitivity.

Binasal visual field defects from simultaneous bilateral retinal infarctions in sickle cell disease.

PURPOSE: To report a case of retinal occlusive disease producing binasal visual field defects in a patient with sickle cell (SC) disease. DESIGN: Retrospective case report. METHODS: A 21-year-old man with SC disease presented with binasal field defects and 20/20 acuity in each eye. RESULTS: Initial ophthalmoscopy and fluorescein angiography revealed no abnormalities. Optical coherence tomography (OCT) demonstrated bilateral temporal inner retinal hyperreflectivity, and multifocal electroretinography (mfERG) confirmed retinal dysfunction. Several weeks later, ophthalmoscopy and angiography demonstrated macular arteriolar occlusive disease. CONCLUSIONS: Simultaneous bilateral macular occlusive events are uncommon in patients particularly with SC disease. Although the binasal field defects raised the suspicion of a process affecting the optic nerves, the OCT and mfERG proved essential in diagnosing retinal rather than optic nerve disease.

Recurrent vitreous hemorrhage secondary to haptic-induced chafing.

CASE REPORT: After cataract extraction and placement of a posterior chamber intraocular lens, a 70-year-old man had 5 vitreous hemorrhages over 3 years. Iris transillumination defects and apposition of the nasal haptic and ciliary body were found. COMMENTS: Iris chafing is a rare complication of cataract extraction. Vitreous hemorrhage presumably resulted from iris erosion caused by the IOL haptic.

Age-dependent effects on cisapride-induced QTc prolongation in the isolated guinea pig heart.

INTRODUCTION: The isolated guinea pig heart preparation has been suggested as a suitable small animal model for investigating potential for QTc prolongation. The purpose of this study was to investigate the effect of age on electrophysiological parameters measured in the isolated guinea pig heart preparation. In addition, the effect of a compound known to prolong the QT interval (cisapride) was investigated in both young and adult guinea pigs. METHODS: Male guinea pigs were divided into 2 groups (n=6). One group of guinea pigs was between 3 and 4 weeks old (young) and the other group was between 16 and 17 weeks old (adult). Concentrations (0, 1, 5, and 50 ng/mL; 2, 11, and 110 nM) of cisapride were perfused for 15 min from low to high concentration. Measurements of PR, QRS, RR and QT intervals were typically made on 5 consecutive electrocardiogram complexes during the last minute of each concentration. The QT interval was corrected for changes in heart rate using the cube root formula of Fridericia (QTcF). RESULTS: Adult guinea pigs had significantly longer RR and QTcF intervals when compared to young animals. Cisapride prolonged QTcF in both young and adult animals at the same concentrations (5 ng/mL and 50 ng/mL). The maximal change in QTcF at 50 ng/mL was similar in young (44+/-3 ms) and adult animals (40+/-1 ms). DISCUSSION: In summary, the present study demonstrated that there was an increase in the RR and QTcF intervals with age in isolated guinea pig hearts. However, this age difference does not appear to impact the sensitivity of the assay to drug-induced QTcF prolongation.

Analysis of flow in a cone-and-plate apparatus with respect to spatial and temporal effects on endothelial cells.

Endothelial cells, covering the inner surface of vessels and the heart, are permanently exposed to fluid flow, which affects the endothelial structure and the function. The response of endothelial cells to fluid shear stress is frequently investigated in cone-plate systems. For this type of device, we performed an analytical and numerical analysis of the steady, laminar, three-dimensional flow of a Newtonian fluid at low Reynolds numbers. Unsteady oscillating and pulsating flow was studied numerically by taking the geometry of a corresponding experimental setup into account. Our investigation provides detailed information with regard to shear-stress distribution at the plate as well as secondary flow. We show that: (i) there is a region on the plate where shear stress is almost constant and an analytical approach can be applied with high accuracy; (ii) detailed information about the flow in a real cone-plate device can only be obtained by numerical simulations; (iii) the pulsating flow is quasi-stationary; and (iv) there is a time lag on the order of 10(-3) s between cone rotation and shear stress generated on the plate.

Development of a structured interview scale for measuring quality of life of the severely mentally ill.

An objective, semi-structured interview questionnaire (QOLIS) was designed and tested with 201 severely mentally ill people who were living in a state hospital and in community residential facilities. Factor analysis resulted in eight factors with face validity and acceptable coefficient alphas. The factors were found to be related meaningfully to overall level of functioning, total symptom scores, self-reported life satisfaction, and an established objective measure of quality of life. Criterion validity was established and the QOLIS factors significantly differentiated people who were living in the community vs. living in a state hospital. These results suggest that the QOLIS has potential as a valid outcome measure and program evaluation tool.

Relationships among selected attributes and three measures of upper body strength and endurance in elementary school children.

The purpose of this investigation was to assess (a) proportions of children unable to perform each of three measures of upper body strength and endurance--pull-up, flexed-arm hang, and modified pull-up; (b) relationships among selected attribute variables of age, weight, percent body fat, and body mass index, and the three measures of upper body strength and endurance; and (c) the attribute variables which best predict scores for the three measures of upper body strength and endurance. Subjects were 104 elementary school children in Grades 1 through 6. Percentages of children obtaining zero scores were computed. Intercorrelations among the attribute and upper body strength and endurance variables were examined for significance and effect size. For each of the three measures of upper body strength and endurance, a max R2 forward stepwise, multiple regression analysis was performed to identify which attribute variables best predict the score of that particular measure. Analyses indicated that age and percent body fat were the best predictors of pull-up and flexed-arm hang scores, whereas age and body mass index best predicted the modified pull-up score.

The development and construct validation of a consumer satisfaction questionnaire for psychiatric inpatients.

A consumer satisfaction scale was developed for psychiatric inpatients. The scale was administered to a state-wide sample of (n = 366) patients discharged from acute psychiatric units throughout Missouri. The scale was factor analyzed and given to another sample of (n = 390) discharges. Three out of five factors that were found in the first sample were replicated in a factor analysis of data from the second sample. Acceptable coefficient alphas were obtained on all three factors, demonstrating internal reliability. The three factors were labeled Treatment Effectiveness, Trust of Staff, and Hospital Environment. Comparable levels of satisfaction with prior studies were found on the first general satisfaction factor of Treatment Effectiveness. Subjects discriminated areas of satisfaction by expressing higher levels of dissatisfaction on the factors of Trust of Staff and Hospital Environment.

Personality mechanisms of alcohol-related violence.

Personality variables involved in alcohol-related violence were studied by comparing MMPI scores of four different groups (N = 259): (1) men who committed murder while intoxicated (violent while intoxicated condition); (2) men who committed murder while sober (violent while sober condition); (3) those who were admitted to a psychiatric unit with a nonalcohol and nonviolence related problem (nonviolent and nonintoxicated condition); and (4) those admitted to a detoxification unit with no evidence of violence prior to admission (nonviolent but intoxicated condition). The violent groups were found to be more paranoid but less manic than the nonviolent groups. Men who commit murder while sober tend to be less interpersonally sensitive (low MF scores) but more psychopathic (high PD scores) than those who commit murder while intoxicated. Those who commit murder while intoxicated tend to be less psychologically minded (high L scores) than those who become intoxicated but who do not kill. Suggestions for prevention and treatment of violence and future research directions are proposed in light of these results.

The development and cross-validation of an MMPI typology of murderers.

A sample of 80 male offenders charged with premeditated murder were divided into five personality types using MMPI scores. A hierarchical clustering procedure was used with a subsequent internal cross-validation analysis using a second sample of 80 premeditated murderers. A Discriminant Analysis resulted in a 96.25% correct classification of subjects from the second sample into the five types. Clinical data from a mental status interview schedule supported the external validity of these types. There were significant differences among the five types in hallucinations, disorientation, hostility, depression, and paranoid thinking. Both similarities and differences of the present typology with prior research was discussed. Additional research questions were suggested.

Cognitive and behavioral predictors of MMPI scores in pretrial psychological evaluations of murderers.

Tested by multivariate regression the validity of the MMPI with accused murderers (N = 96) who were undergoing pre-trial evaluations. Four significant behavioral and cognitive predictors of MMPI elevated scores were identified. These include low intelligence, history of drug abuse, suspiciousness observed on the ward, and the fact that the accused was a stranger to the victim. These results support the validity of the MMPI with this population and also suggest that high F scale scores on the MMPI are more a measure of psychopathology than invalidity due to test-taking response bias.

Are separate black and white MMPI norms needed? An IQ-controlled comparison of accused murderers.

Investigated racial differences in MMPI responding by comparing samples of black and white males charged with murder (N = 160). Mancova was used to control statistically for the effects of intelligence on racial differences. Prior to the use of Mancova blacks had significantly higher scores on F and MA. When the effects of intelligence were controlled F and MA were no longer significantly different for blacks and whites. However, with black and white SS equated on IQ, significant differences emerged on the K and SI scales. These results indicate that construction of separate black and white norms for violent offenders is premature. More research is needed on variables that affect individual differences on the MMPI.