Long-term probability distribution of fixed offshore structuralresponse using animproved version of finite memory nonlinear system procedure

Offshore structures are exposed to random wave loading in the ocean environment and hence the probability distribution of the extreme values of their response to wave loading is required for their safe and economical design. Due to nonlinearity of the drag component of Morison’s wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian [1-2]; therefore, simple techniques for derivation of the probability distribution of extreme responses are not available. However, it has recently been shown that the short-term response of an offshore structure exposed to Morison wave loading can be approximated by the response of an equivalent finite-memory nonlinear system (FMNS) [3]. Previous investigation shows that the developed FMNS models reduce the computational effort but the predictions are not very good for low intensity sea states. Therefore, to overcome this deficiency, a modified version of FMNS models is referred to as MFMNS models is used to determine the extreme response values which improves the accuracy but is computationally less efficient than FMNS models. In this paper, the 100-year responses derived from the long-term probability distribution of the extreme responses from MFMNS and FMNS models are compared with corresponding distributions from the CTS method is investigated with the effect of current to establish their level of accuracy. The methodology for derivation of the long-term distribution of extreme responses (and the evaluation of 100-year responses) is discussed. The accuracy of the predictions of the 100- year responses from MFMNS and FMNS models will then be investigated

Comparison of the extreme responses from different methods of simulating wave kinematics

Linear random wave theory (LRWT) is frequently used to simulate water particle kinematics at different nodes of an offshore structure from a reference surface elevation record. However, it is well known that LRWT leads to water particle kinematics with exaggerated high-frequency components in the vicinity of mean water level (MWL). Methods have been introduced to overcome this problem of high kinematics above the MWL consists of using linear wave theory (such as Wheeler, vertical stretching, effective node elevation and effective water depth methods) can be used to provide a more realistic representation of near- surface wave kinematics. There is promising as there is some evidence that the water particle kinematics from the Wheeler method are underestimated and that those from the vertical stretching method are somewhat exaggerated. In this paper, the comparisons of the probability distributions of extreme values from different methods of simulation wave kinematics are investigated by using Monte Carlo simulation procedure

Association between sleep duration and diabetes mellitus: Isfahan Healthy Heart Program

Background: Recent studies revealed an association between sleep disturbance and metabolic disorders, such as obesity and metabolic syndrome. An aim of this study was to assess the relation between sleep duration and diabetes mellitus in a representative sample of the Iranian population.Materials and Methods: Participants were 12514 individuals, (6123 men  and 6391 women) studied in the baseline survey of a community based program entitled Isfahan healthy heart program (IHHP). Sleep time was obtained by validated questionnaire. Diabetes mellitus was defined as fasting glucose over 126 mg/dl or 2 hour post prandial glucose at glucose tolerance test over 200 mg/dl, or if the patient was on diabetic medication. The relation between the sleep time and diabetes was examined using categorical logistic regression with adjustment for sex, body mass index and waist circumference.Results: Compared with those, sleeping 7.8 hours per night, the  individuals with sleeping time of 5 hours or less and aged <60 years had an increased odd ratio for diabetes and an impaired glucose tolerance. (OR = 1.37 and 95% CI = 1.13,1.67).Conclusion: Sleep duration of 5 hours or less in individuals under age 60 years is associated with an increased prevalence of diabetes mellitus and an impaired glucose tolerance test. This finding should be confirmed in longitudinal studies.Key words: Diabetes mellitus, glucose tolerance, slee

Reduced elastogenesis: a clue to the arteriosclerosis and emphysematous changes in Schimke immuno-osseous dysplasia?

BACKGROUND: Arteriosclerosis and emphysema develop in individuals with Schimke immuno-osseous dysplasia (SIOD), a multisystem disorder caused by biallelic mutations in SMARCAL1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1). However, the mechanism by which the vascular and pulmonary disease arises in SIOD remains unknown. METHODS: We reviewed the records of 65 patients with SMARCAL1 mutations. Molecular and immunohistochemical analyses were conducted on autopsy tissue from 4 SIOD patients. RESULTS: Thirty-two of 63 patients had signs of arteriosclerosis and 3 of 51 had signs of emphysema. The arteriosclerosis was characterized by intimal and medial hyperplasia, smooth muscle cell hyperplasia and fragmented and disorganized elastin fibers, and the pulmonary disease was characterized by panlobular enlargement of air spaces. Consistent with a cell autonomous disorder, SMARCAL1 was expressed in arterial and lung tissue, and both the aorta and lung of SIOD patients had reduced expression of elastin and alterations in the expression of regulators of elastin gene expression. CONCLUSIONS: This first comprehensive study of the vascular and pulmonary complications of SIOD shows that these commonly cause morbidity and mortality and might arise from impaired elastogenesis. Additionally, the effect of SMARCAL1 deficiency on elastin expression provides a model for understanding other features of SIOD

Various methods of simulating wave kinematics on the structural members of 100-year responses

The main force acting on an offshore structure is usually due to wind-generated random waves. According to the Morison equation, the wave force on a cylindrical member of an offshore structure depends on wave kinematics at the centre of the element. It is therefore essential to accurately estimate the magnitude of wave-induced water particle kinematics at all points in a random wave field. Linear random wave theory (LRWT) is the most-frequently used theory to simulate water particle kinematics at different nodes of an offshore structure. Several empirical techniques have been suggested to provide a more realistic representation of the near-surface wave kinematics. The empirical techniques popular in the offshore industry include Wheeler stretching and vertical stretching. Most recently, two new effective methods (effective node elevation and the effective water depth) have been recently introduced. The problem is that these modified methods differ from one another in their predictions. Hence, the aim of this study is to investigate the effects of predicting the 100-year responses from various methods of simulating wave kinematics accounting for the current effect. In this paper, four versions of the wave kinematics procedure have been tested by comparing the short-term probability distributions of extreme responses. For all current cases, the highest vertical ratios for zero, positive and negative current cases are 1.414, 1.175 and 1.831, respectively. It is observed that even for positive-current cases, the difference between Wheeler and vertical stretching predictions is quite high and cannot be neglected. Thus, further investigation is necessary to resolve this problem and the outcomes in providing useful design information for the oil and gas industry

Characterization of early disease status in treatment-naive male paediatric patients with Fabry disease enrolled in a randomized clinical trial.

Trial designThis analysis characterizes the degree of early organ involvement in a cohort of oligo-symptomatic untreated young patients with Fabry disease enrolled in an ongoing randomized, open-label, parallel-group, phase 3B clinical trial.MethodsMales aged 5-18 years with complete α-galactosidase A deficiency, without symptoms of major organ damage, were enrolled in a phase 3B trial evaluating two doses of agalsidase beta. Baseline disease characteristics of 31 eligible patients (median age 12 years) were studied, including cellular globotriaosylceramide (GL-3) accumulation in skin (n = 31) and kidney biopsy (n = 6; median age 15 years; range 13-17 years), renal function, and glycolipid levels (plasma, urine).ResultsPlasma and urinary GL-3 levels were abnormal in 25 of 30 and 31 of 31 patients, respectively. Plasma lyso-GL-3 was elevated in all patients. GL-3 accumulation was documented in superficial skin capillary endothelial cells (23/31 patients) and deep vessel endothelial cells (23/29 patients). The mean glomerular filtration rate (GFR), measured by plasma disappearance of iohexol, was 118.1 mL/min/1.73 m(2) (range 90.4-161.0 mL/min/1.73 m(2)) and the median urinary albumin/creatinine ratio was 10 mg/g (range 4.0-27.0 mg/g). On electron microscopy, renal biopsy revealed GL-3 accumulation in all glomerular cell types (podocytes and parietal, endothelial, and mesangial cells), as well as in peritubular capillary and non-capillary endothelial, interstitial, vascular smooth muscle, and distal tubules/collecting duct cells. Lesions indicative of early Fabry arteriopathy and segmental effacement of podocyte foot processes were found in all 6 patients.ConclusionsThese data reveal that in this small cohort of children with Fabry disease, histological evidence of GL-3 accumulation, and cellular and vascular injury are present in renal tissues at very early stages of the disease, and are noted before onset of microalbuminuria and development of clinically significant renal events (e.g. reduced GFR). These data give additional support to the consideration of early initiation of enzyme replacement therapy, potentially improving long-term outcome.Trial registrationClinicalTrials.gov NCT00701415

Cooling dynamics of carbon cluster anions

A series of ion storage experiments on small carbon cluster anions was conducted to understand size-dependent cooling processes. The laser-induced delayed electron detachment time profile show clear even/odd alternation due to the presence of the electronic cooling. The time evolution of the internal energy distribution was simulated for Cn- (n=4 to 7) with a common procedure taking vibrational and electronic cooling into account