3D parameter to quantify the anisotropy measurement of periodic structures on rough surfaces.

In this paper, a new 3D roughness parameter, Sreg, is proposed to quantify the regularity of a surface, independent of the amplitude and the scanning length units of the surface. The efficiency of this parameter is tested on noisy periodical surfaces with degrees of anisotropy. This parameter lies between zero (perfect noise) and 100% (a perfect periodic surface). This parameter enables the identification of the anisotropy directions of regularity for a given surface. For a periodical surface, the greater the noise, the lower the anisotropy. A direction function is proposed to analyse the direction of regularity of a rough surface, which then permits characterization of the directional regularity of the topography. The regularity parameter can be used for several purposes: to identify the direction of periodical structures formed by laser-pulsed radiations on the surface of solid workpieces; to examine the reproducibility of surface machining methods such as finishing process; and to identify the surface regularity produced by abrasive machining, such as precision surface grain, abrasive slotting, and lapping.

Mid-term prognostic value of coronary artery disease in patients undergoing transcatheter aortic valve implantation: a meta-analysis of adjusted observational results.

AIMS: Coronary artery disease (CAD) negatively affects prognosis in patients undergoing surgical aortic valve replacement, being currently evaluated in the most common used risk score. Our meta-analysis aims to clarify the prognostic role of CAD on mid-term survival in patients undergoing TAVI. METHODS AND RESULTS: Studies reporting multivariate predictors of adverse outcomes in patients undergoing TAVI were systematically searched for and pooled, when appropriate, using a random-effect method. 960 citations were first screened and finally 7 studies (2472 patients) were included. Diagnosis of CAD was reported in 52%(42-65) of patients and 1169 Edwards SAPIEN and 1303 CoreValve prostheses were implanted. After a median follow up of 452 days (357-585) 24% of patients (19-33) died, and 23 (14-32) for cardiovascular death. At pooled analysis of multivariate approach, diagnosis of coronary artery disease did not increase risk of death (OR 1.0, 95% CI, confidence interval, 0.67-1.50 I(2) 0%). CONCLUSION: CAD does not affect mid-term TAVI outcome: this finding should be weighted to accurately evaluate risk and strategies for patients with severe aortic stenosis.

Role of the kidneys in resistant hypertension.

Resistant hypertension is a failure to achieve goal BP (<140/90 mm Hg for the overall population and <130/80 mm Hg for those with diabetes mellitus or chronic kidney disease) in a patient who adheres to maximum tolerated doses of 3 antihypertensive drugs including a diuretic. The kidneys play a critical role in long-term regulation of blood pressure. Blunted pressure natriuresis, with resultant increase in extracellular fluid volume, is an important cause of resistant hypertension. Activation of the renin-angiotensin-aldosterone system, increased renal sympathetic nervous system activity and increased sodium reabsorption are important renal mechanisms. Successful treatment requires identification and reversal of lifestyle factors or drugs contributing to treatment resistance, diagnosis and appropriate treatment of secondary causes of hypertension, use of effective multidrug regimens and optimization of diuretic therapy. Since inappropriate renal salt retention underlies most cases of drug-resistant hypertension, the therapeutic focus should be on improving salt depleting therapy by assessing and, if necessary, reducing dietary salt intake, optimizing diuretic therapy, and adding a mineralocorticoid antagonist if there are no contraindications.

HIV/AIDS in Bangladesh: an assessment of biomedical risk factors for transmission.

Behavioural risk factors for HIV/AIDS in Bangladesh were reviewed in a preceding article in this journal. Omitted from that review was a discussion of potential biomedical risk factors including: (i) an unregulated blood supply system in which blood used in transfusions is not screened for HIV and is donated primarily by professional donors: (ii) unsterile injections in non-formal and formal health-care settings; and (iii) a high prevalence in high-risk groups of other sexually transmitted diseases (STDs) which may function as co-factors for HIV transmission, particularly if chronically untreated. Studies elsewhere in the world suggest that the unregulated blood supply system, in particular, poses a serious danger in terms of the spread of the HIV epidemic. While certain socio-cultural factors may be contributing to low levels of HIV in Bangladesh, the prevalence of biomedical and behavioural risk factors suggest the importance of implementing targeted cost-effective interventions now.

Behavioural risk factors for HIV/AIDS in a low-HIV prevalence Muslim nation: Bangladesh.

A review of published and unpublished data indicates the prevalence of high-risk behaviours for HIV transmission in segments of the Bangladeshi population. These include casual unprotected sex, heterosexual as well as between males, prior to and after marriage. Intravenous drug use (IVDU) exists though illicit drugs are more commonly inhaled. There is a fear, however, that inhalers may turn to injecting drugs, as is common in neighbouring countries. The lack of public awareness of HIV/AIDS, and misconceptions about the disease, may contribute to continued high-risk behaviours by segments of the population and, thus, to the spread of HIV. Bangladesh's proximity to India and Myanmar (countries with high HIV endemicity and a rapidly growing number of cases) increases fears of an epidemic in Bangladesh. This proximity will only be a risk factor, however, if high-risk contacts occur between nationals of these countries.