Validation of a turbulent Kelvin-Helmholtz shear layer model using a high-energy-density OMEGA laser experiment.

Following the successful demonstration of an OMEGA laser-driven platform for generating and studying nearly two-dimensional unstable plasma shear layers [Hurricane et al., Phys. Plasmas 16, 056305 (2009); Harding et al., Phys. Rev. Lett. 103, 045005 (2009)], this Letter reports on the first quantitative measurement of turbulent mixing in a high-energy-density plasma. As a blast wave moves parallel to an unperturbed interface between a low-density foam and a high-density plastic, baroclinic vorticity is deposited at the interface and a Kelvin-Helmholtz instability-driven turbulent mixing layer is created in the postshock flow due to surface roughness. The spatial scale and density profile of the turbulent layer are diagnosed using x-ray radiography with sufficiently small uncertainty so that the data can be used to ~0.17 µm) in the postshock plasma flow are consistent with an "inertial subrange," within which a Kolmogorov turbulent energy cascade can be active. An illustration of comparing the data set with the predictions of a two-equation turbulence model in the ares radiation hydrodynamics code is also presented.

Observation of a Kelvin-helmholtz instability in a high-energy-density plasma on the omega laser.

A laser initiated experiment is described in which an unstable plasma shear layer is produced by driving a blast wave along a plastic surface with sinusoidal perturbations. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vortices characteristic of the Kelvin-Helmholtz instability. The experiment used x-ray radiography to capture the first well-resolved images of Kelvin-Helmholtz vortices in a high-energy-density plasma.

Dynamic Hohlraums as x-ray sources in high-energy density science.

The first demonstration of laser driven dynamic Hohlraums (LDDH) as a spectrally smooth backlighter source for opacity and temperature measurements through absorption spectrometry of materials in local thermodynamic equilibrium at temperatures >150 eV has been made. This is a crucial temperature regime for future astrophysics and ignition fusion experiments at the nearly completed National Ignition Facility (NIF) [E. I. Moses and C. R. Wuest, Fusion Sci. Technol. 47, 314 (2005)] at the Lawrence Livermore National Laboratory. The new backlighter consists of a LDDH filled with either krypton or argon that implodes to create an x-ray flash. The properties of this x-ray flash have been measured in experiments at the Omega laser [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] at the Laboratory for Laser Energetics in Rochester, New York, satisfying all requirements imposed by future experiments: (1) the emission spectrum extends to at least 5.5 keV, well above the maximum x-ray energy ( approximately 3.5 keV) obtained from the previously "best" opacity backlighters (uranium M-shell emission backlighters); (2) the spectrum is smooth and featureless (intensity variation <6% rms), allowing absorption spectrometry through experimental samples; (3) the emission source size is sufficiently small (<50 microm) for projection backlighting through future samples; (4) the emission is bright enough (and twice as bright as imploding hydrogen-filled capsules) for gated spectrometer measurements; (5) the emission duration is optimized ( approximately 100 ps) for the current and future generations of spectrometers; and (6) by using only a small number of beams with limited energy and symmetry for the backlighter (10 out of 60 beams in the Omega experiments), the majority of laser beams are left available for heating sample materials to >150 eV.

C-reactive protein, heart rate variability and prognosis in community subjects with no apparent heart disease.

OBJECTIVES: Increased C-reactive protein (CRP) and reduced heart rate variability (HRV) both indicate poor prognosis. An inverse association between HRV and CRP has been reported, suggesting an interaction between inflammatory and autonomic systems. However, the prognostic impact of this interaction has not been studied. We thus investigated the prognostic impact of CRP, HRV and their combinations. DESIGN: Population-based study. SUBJECTS: A total of 638 middle-aged and elderly subjects with no apparent heart disease from community. METHODS: All were studied by clinical and laboratory examinations, and 24-h Holter monitoring. Four time domain measures of HRV were studied. All were prospectively followed for up to 5 years. RESULTS: Mean age was 64 years (55-75). During the follow-up, 46 total deaths and 11 cases of definite acute myocardial infarction were observed. Both CRP and three of four HRV measures were significantly associated with increased rate of death or myocardial infarction. In a Cox model with CRP >or=2.5 microg mL(-1), standard deviation for the mean value of the time between normal complexes

Measurement of the decay rate of single-frequency perturbations on blast waves.

To explore the validity of theories forwarded to explain the dynamics of hydrodynamic perturbations on high Mach number blast waves, we have studied the decay rate of perturbations on blast waves traveling through nitrogen gas. In our experiments, 1 kJ pulses from the Z-Beamlet laser at Sandia National Laboratories illuminated solid targets immersed in gas and created blast waves. The polytropic index implied by comparing experiment to theoretical predictions is compared to simulation results.

Neuroendocrine testing in community patients with heart disease: plasma N-terminal proatrial natriuretic peptide predicts morbidity and mortality stronger than catecholamines and heart rate variability.

BACKGROUND: Patients with heart disease are at risk of developing congestive heart failure (CHF). Neurohormonal activation may make an important contribution. AIM: In stable heart patients from primary care, to examine neuroendocrine markers of cardiac performance for the association to cardiac dysfunction, morbidity and mortality. METHODS: Plasma N-terminal atrial natriuretic peptide (N-ANP), catecholamines, 24-h ECG and blood pressure, serum urea and creatinine, echocardiography, chest X-ray and physical examination were performed. Death was recorded during 5 to 7 years of follow-up. RESULTS: The study included 56 patients. Mean age was 71 years, 54% were men, 43% had clinical signs of CHF, 39 + 52 + 9% were in NYHA I + II + III, 34% had echocardiographic cardiac dysfunction, and 18 died during follow-up. N-ANP was related to all subtypes of cardiac dysfunction (p < 0.05). Catecholamines and premature ventricular captures (PVC) were related to valvular and systolic dysfunction, but heart rate variability and dipping blood pressure were not (p > 0.05). On multivariate analyses only, N-ANP and PVC were associated with clinical signs of CHF, echocardiographic cardiac dysfunction, and mortality (p < 0.05). CONCLUSIONS: Plasma N-ANP was stronger than catecholamines and variables of 24-h monitoring (blood pressure and electrocardiogram) in predicting morbidity and mortality, thereby supporting the use of cardiac natriuretic peptides (i.e. N-ANP, BNP, or N-BNP) as the most valuable biomarker in community patients at risk of CHF.

Time- and concentration-dependent increases in cell proliferation in rats and mice administered vinyl acetate in drinking water.

Chronic administration of vinyl acetate (VA) in drinking water to rats and mice has produced upper digestive tract neoplasms. These tumors were believed to arise from the intracellular metabolism of VA by carboxylesterases to cytotoxic and genotoxic compounds. We hypothesized that prolonged VA exposure at high concentrations would induce cytotoxicity and a restorative cell proliferation (CP). These endpoints were measured in F-344 rats and BDF1 mice administered drinking water containing 0, 1000, 5000, 10,000, or 24,000 ppm VA for 92 days. On test days, Days 1, 8, 29, and 92, upper digestive tract histopathology and oral cavity CP (pulsed 5-bromodeoxyuridine [BrdU] to measure S-phase DNA synthesis) were evaluated. Analysis of test solutions showed that VA spontaneously hydrolyzed, slowly releasing acetic acid and thereby lowering pH. Statistically significant, concentration-related increases in CP occurred in basal cells of the mandibular oral cavity mucosa of mice at 10,000 and 24,000 ppm but only after 92 days. CP increases were approximately 2.4- and 3.4-fold above controls and were considered to be toxicologically significant. Some statistically significant increases in CP were also measured in the oral cavity mucosa of rats; however, these changes were considered to be of equivocal biological relevance. No histopathological evidence of mucosal injury was seen in either species. The absence of cytotoxicity in the upper digestive tract mucosa suggests that the increased CP at high administered VA concentrations may be due to a mitogenic response, ostensibly from the loss of cell growth controls in oral cavity mucosa.

Inhalation toxicity of tetramethylurea in rats.

Tetramethylurea (TMU, CAS No. 632-22-4) was tested for its inhalation toxicity in rats following repeated exposures. Male rats were exposed whole-body to TMU for 6 hours/day, 5 days/week for a total of 9 exposures over 2 weeks. Concentrations of 0 (control), 2, 20, and 100 ppm were studied. Four groups of 10 rats each were used to measure clinical signs and growth, clinical pathology (including hematology, biochemistries, and urine analysis), and tissue pathology. One-half of the rats were sacrificed 1 day following the 9th exposure; the other half underwent an 18-day recovery period prior to being sacrificed (recovery group). Body weight gains in rats exposed to 100 ppm were reduced as compared to the controls; no body weight effects were seen in either 2 or 20 ppm rats and no clinical signs of toxicity were observed in rats at any of the levels throughout the study. No compound-related clinical pathology changes were seen in any of the test groups and tissue pathology effects only occurred in the nasal tissue. In rats exposed to 100 ppm, microscopic observations of degeneration, necrosis, and ulceration of olfactory mucosa was seen. These lesions were still present but seen as recovering and healing after the 18-day recovery. Under the conditions of this test, the no-observed-adverse-effect level (NOAEL) was determined to be 20 ppm based upon both body weight changes and upper respiratory tract pathologic changes in 100 ppm rats.

Acute and subchronic neurotoxicological evaluation of tetrahydrofuran by inhalation in rats.

Groups of adult male and female rats received exposure to tetrahydrofuran (THF) vapor by inhalation in acute or subchronic exposure scenarios. Acute exposure concentrations were 0, 500, 2500, or 5000 ppm for 6 hr. Evaluations conducted immediately after exposure included clinical observations, motor activity assessments (MA), and a battery of functional tests (FOB) designed to reveal nervous system dysfunction. During exposure to 2500 and 5000 ppm, rats had a diminished or absent startle response to a punctate auditory alerting stimulus. Following exposure to 5000 ppm, male and female rats were lethargic, exhibited abnormal gait or mobility, and splayed rear feet. Lethargy and splayed rear feet were also observed in females exposed to 2500 ppm. During the subsequent FOB, males exposed to 5000 ppm had a lower incidence of palpebral closure, higher incidences of slow or absent righting reflex, and a biphasic pattern of reduced motor activity followed by increased motor activity. Females exposed to 5000 ppm had increased incidences of palpebral closure in the open field, increased incidences of slow or absent righting reflex, and decreased motor activity. During the 14-week subchronic exposure series, daily THF exposure concentrations were 0, 500, 1500, or 3000 ppm, and neurobehavioral evaluations occurred on non-exposure days at approximately monthly intervals. Diminished startle responses to an auditory alerting stimulus were observed during exposure to 1500 or 3000 ppm; however, repeated exposures did not cause additional neurobehavioral or pathological effects. This pattern of effects is suggestive of transient sedation. Despite daily reinstatement of acute sedative effects during repeated exposure with up to 3000 ppm, THF did not produce any persistent or cumulative effects on nervous system structure or function. The demonstrated no-observed-effect level of THF for both acute and subchronic exposure was 500 ppm.

Cross sectional study estimating prevalence of heart failure and left ventricular systolic dysfunction in community patients at risk.

OBJECTIVE: To examine a general practice population to measure the prevalence of signs and symptoms of heart failure (SSHF) and left ventricular systolic dysfunction (LVSD). DESIGN: Cross sectional screening study in three general practices followed by echocardiography. SETTING AND PATIENTS: All patients >/= 50 years in two general practices and >/= 40 years in one general practice were screened by case record reviews and questionnaires (n = 2158), to identify subjects with some evidence of heart disease. Among these, subjects were sought who had SSHF (n = 115). Of 357 subjects with evidence of heart disease, 252 were eligible for examination, and 126 underwent further cardiological assessment, including 43 with SSHF. MAIN OUTCOME MEASURES: Prevalence of SSHF as defined by a modified Boston index, LVSD defined as an indirectly measured left ventricular ejection fraction /= 50 years of age 6.4% had SSHF, 2.9% had LVSD, and 1.9% (95% confidence interval 1.3% to 2.5%) had both. To detect one case with LVSD in primary care, 14 patients with evidence of heart disease without SSHF and 5.5 patients with SSHF had to be examined. CONCLUSION: SSHF is extremely prevalent in the community, especially in primary care, but more than two thirds do not have LVSD. The number of subjects with some evidence of heart disease needing an echocardiogram to detect one case of LVSD is 14.

Heart rate-lowering calcium antagonists in hypertensive post-myocardial infarction patients.

OBJECTIVES: To analyse effects of a heart rate-lowering calcium antagonist in hypertensive post-myocardial infarction patients. DESIGN AND METHODS: From three large, randomized, placebo-controlled, secondary prevention trials investigating verapamil or diltiazem (the first and second Danish Verapamil Infarction Trials and the Multicentre Diltiazem Post-Infarction Trial) data from a total of 1,325 hypertensive post-myocardial infarction patients (drugs = 667, placebo = 658) were pooled to assess effect of blinded therapy on mortality and event rates. RESULTS: Treatment with heart rate-lowering calcium antagonists was associated with significant reduction in event rates [21.4 versus 27.4%; risk ratio (RR) = 0.76, confidence interval (CI) = 0.61 -0.95, P= 0.013]. Mortality rates in the treatment group were 15.1 versus 17.5% in the control group (RR = 0.87, CI = 0.66-1.13, P= 0.296). Among the subset of 964 hypertensive patients without pulmonary congestion, there was some reduction in mortality rate (11.3 versus 15.3% in the control group; RR = 0.72, P= 0.066) and significant reduction in event rates (18 versus 24.4% for control group; RR = 0.70, P= 0.011). In patients with pulmonary congestion and hypertension, however, calcium antagonists were associated with a 25% increase in mortality (RR = 1.25, P= 0.339), while event rate RR was 1.00. After an adjustment for significant covariates, RR for mortality in treatment versus control groups was 0.76 (P= 0.159). For event rates, RR was 0.74 (P= 0.057). CONCLUSIONS: Heart rate-lowering calcium antagonists decrease event rates in hypertensive post-myocardial infarction patients, but only in those without pulmonary congestion.

N-losses and energy use in a scenario for conversion to organic farming.

The aims of organic farming include the recycling of nutrients and organic matter and the minimisation of the environmental impact of agriculture. Reduced nitrogen (N)-losses and energy (E)-use are therefore fundamental objectives of conversion to organic farming. However, the case is not straightforward, and different scenarios for conversion to organic farming might lead to reduced or increased N-losses and E-use. This paper presents a scenario tool that uses a Geographical Information System in association with models for crop rotations, fertilisation practices, N-losses, and E-uses. The scenario tool has been developed within the multidisciplinary research project Land Use and Landscape Development Illustrated with Scenarios (ARLAS). A pilot scenario was carried out, where predicted changes in N-losses and E-uses following conversion to organic farming in areas with special interests in clean groundwater were compared. The N-surplus and E-use were on average reduced by 10 and 54%, respectively. However, these reductions following the predicted changes in crop rotations, livestock densities, and fertilisation practices were not large enough to ensure a statistically significant reduction at the 95% level. We therefore recommend further research in how conversion to organic farming or other changes in the agricultural practice might help to reduce N-surpluses and E-uses. In that context, the presented scenario tool would be useful.

Subchronic toxicity of cyclohexane in rats and mice by inhalation exposure.

Inhalation studies were conducted to determine the potential toxicity and/or potential neurotoxicity of cyclohexane. Groups of rats and mice were exposed to 0, 500, 2000, or 7000 ppm concentrations of cyclohexane vapor 6 hr/day, 5 days/week for 14 weeks. Subgroups of rats and mice were further observed during a 1-month recovery period. Functional observational battery (FOB) and motor activity (MA) behavioral tests were conducted on rats. These tests were conducted prior to the exposure series and during weeks 4, 8, and 13 on non-exposure days. Clinical pathology evaluations were conducted after approximately 7, 13, and 18 weeks. Approximately 14 and 18 weeks after study initiation, tissues from rats and mice were histologically processed and evaluated by light microscopy. During exposure to 2000 or 7000 ppm, rats and mice had a diminished response or an absent response to delivery of a punctate auditory alerting stimulus. Immediately following removal of rats from the inhalation chambers, 7000 ppm males and females and 2000 ppm females displayed a compound-related increase in the incidence of wet and/or stained fur (which occurred in the areas of the mouth, chin, and/or perineum). These signs were transient, were not observed during exposure or prior to exposure the following day, and were not associated with any behavioral or morphological changes. During exposure sessions, mice exposed to 7000 ppm exhibited clinical signs of toxicity which included hyperactivity, circling, jumping/hopping, excessive grooming, kicking of rear legs, standing on front legs, and occasional flipping behavior. Clinical signs of toxicity observed in 7000 ppm mice immediately after exposure included hyperactivity, hyperreactivity, ruffled fur (females only), gait abnormalities, spasms in both rear legs, and excessive grooming (males only). The clinical signs observed in mice during and immediately after exposure were transient, and were not present prior to the subsequent exposure. A few mice exposed to 2000 ppm appeared hyperactive during exposure in the latter portion of the study. There were no compound-related changes in mean body weights, body weight gains, food consumption, food efficiency, or mortality; and there were no ophthalmological abnormalities in rats or mice. In addition, there were no compound-related effects on 37 different behavioral parameters assessed during the FOB or during motor activity tests in rats. Male and female mice exposed to 7000 ppm had slight increases in measures of circulating erythrocyte mass (red blood cells, hemoglobin, hematocrit) and plasma protein concentration (males only). Male rats and male and female mice exposed to 7000 ppm had significantly increased relative liver weights, and 7000 ppm male mice also had significantly increased absolute liver weights at the end of the exposure period. At the end of the 1-month recovery period, absolute and relative liver weights of male and female mice were similar to control. However, relative liver weights of 7000 ppm male rats continued to be significantly higher at the end of the recovery period. Male and female rats exposed to 7000 ppm had a significantly increased incidence of hepatic centrilobular hypertrophy at the end of the exposure period, which was not observed at the conclusion of the 1-month recovery period. No microscopic changes were observed in mice. In rats, the no-observed-effect level (NOEL) for acute, transient effects was 500 ppm based on a diminished/absent response to an auditory alerting stimulus at 2000 ppm and above. The NOEL for subchronic toxicity in rats was 7000 ppm based on the lack of adverse effects on body weight, clinical chemistry, tissue morphology, and neurobehavioral parameters. In mice, the NOEL for acute, transient effects was 500 ppm based on behavioral changes during exposure at 2000 ppm and above. The NOEL for subchronic toxicity in mice is 2000 ppm based on hematological changes at 7000 ppm.

Chronic toxicity and oncogenicity bioassay in rats with the chloro-s-triazine herbicide cyanazine.

Cyanazine is a member of the chloro-s-triazine class of herbicides. Other triazine herbicides have been shown to induce mammary-gland tumors in rats, although the response is unique to the Sprague-Dawley strain. Cyanazine is nongenotoxic. The present study was conducted to evaluate the chronic toxicity and oncogenic potential of cyanazine. Groups of 62 male and female rats were fed diets containing cyanazine at concentrations of 1, 5, 25, or 50 ppm for up to 2 yr. Mean body weight and body weight gain of male and female rats of the 25- and 50-ppm groups were significantly reduced over the course of the study. Food consumption and food efficiency were also reduced in these groups. Survival was not adversely affected in the treatment groups compared to controls. A significant increase in the incidence of masses of the inguinal region was noted among female rats of the 50-ppm group. These masses were correlated with a significant increase in the incidence of female rats with mammary-gland adenocarcinomas and carcinosarcomas. The incidence of rats with malignant mammary-gland tumors was elevated in the 5-, 25-, and 50-ppm groups, although the incidence within the 5-ppm group was within historical controls. There were no other toxicologically significant observations with respect to ophthalmological, clinical laboratory, or pathological evaluations. Under the conditions of this study, the no-observed-adverse-effect level was 5 ppm. Research into the mechanism of action suggests these mammary tumors are mediated through a prolactin mechanism that is thought to be of low relevance to humans.

Long-term effects of diltiazem and verapamil on mortality and cardiac events in non-Q-wave acute myocardial infarction without pulmonary congestion: post hoc subset analysis of the multicenter diltiazem postinfarction trial and the second danish verapamil infarction trial studies.

The main objective of this retrospective analysis was to evaluate the long-term effect of the heart rate-lowering calcium antagonists verapamil and diltiazem on the incidence of combined cardiac events and all-cause mortality in patients who had experienced a non-Q-wave acute myocardial infarction (AMI), but who did not also have pulmonary congestion. In addition, factors having an independent association with these 2 outcomes were identified. Of 817 non-Q-wave patients, 81 (9.9%) died during 12 to 52 months of follow-up. The unadjusted mortality rate was 42% lower in patients randomized to calcium antagonist therapy than placebo (7.2% vs 12.4%, p = 0.010). Non-Q-wave patients who died during follow-up were older than patients who survived (62 vs 58 years, p = 0.001). Other factors found to have an independent association with all-cause mortality included diuretic use (RR 2.79), diabetes mellitus (RR 2.86), and New York Heart Association class >I (RR 1.73). The covariate adjusted all-cause mortality risk ratio associated with randomization to calcium antagonist therapy was 0.65 (95% confidence interval [0.40 to 1.05, p = 0.079]). Overall, 153 patients (18.7%) died or had nonfatal reinfarction. The unadjusted combined event rate was 31% lower in patients randomized to calcium antagonist therapy than to placebo (15.2% vs 21.9%, p <0.006). Factors found to have an independent association with cardiac events included age, diabetes (RR 2.82), diuretic use (RR 2.04), and previous AMI (RR 1. 71). In addition, randomization to the calcium antagonist group had a significant independent association with reduced cardiac events (p = 0.031). The covariate adjusted event rate RR associated with randomization to the calcium antagonist group was 0.69 (95% confidence interval [0.49 to 0.97]). In conclusion, the heart rate-lowering calcium antagonists diltiazem and verapamil may play an important role in reducing long-term mortality and reinfarction in non-Q-wave AMI without pulmonary congestion.

Blood pressure level and relation to other cardiovascular risk factors in male hypertensive patients without clinical evidence of ischemic heart disease.

Arterial hypertension is accompanied by increased morbidity and mortality and constitutes a substantial part of medical care. Antihypertensive intervention reduces the cardiovascular morbidity and mortality. The aims of the study were to evaluate the relationship between cardiovascular risk factors and the blood pressure (BP), and to evaluate the percentage of patients who had achieved a BP level as recommended by the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). BP was evaluated in relation to age, body mass index, duration of hypertension, cholesterol and triglyceride level, smoking status, information of regular exercise, a family history of ischemic heart disease (IHD) and drug treatment, in 220 men treated for arterial hypertension. In the univariate analyses we found a higher systolic blood pressure (SBP) with older age, higher SBP in smoking patients and lower SBP in patients with regular exercise. In a multivariate model age (p = 0.0004), smoking status (p = 0.01) and regular exercise (p= 0.06) were independently associated with SBP. There was a lower diastolic blood pressure (DBP) with older age, and age was independently associated with DBP. Office SBP was above 140 mmHg in 83% and above 160 mmHg in 44% of patients. During ambulatory blood pressure monitoring (AMBP), SBP was above 135 mmHg in 40% and above 155 mmHg in 15% of patients. In addition to male sex and hypertension there was a high percentage of other cardiovascular risk factors--43% was smoking, 21% had a family history of IHD, 77% had a se-cholesterol above 5.5 mmol/l and 48% had a se-triglyceride above 1.6 mmol/l. In a consecutive group of asymptomatic male treated hypertensive patients SBP is independently associated with age and smoking status, and DBP with age. A high percentage of the patients do not have a well controlled BP, and a high percentage have additional risk factors such as smoking, hypercholesterolaemia, hypertriglyceridaemia and a family history of IHD. This means that there is room for much improvement in the control of hypertension.