Scaling of near-wall flows in quasi-two-dimensional turbulent channels

The law of the wall and the log law rule the near-wall mean velocity profile of three-dimensional turbulent flows. These well-known laws, which are validated by legions of experiments and simulations, may be universal. Here, using a soap-film channel, we report the first experimental test of these laws in quasi-two-dimensional turbulent channel flows under two disparate turbulent spectra. We find that despite the differences with three-dimensional flows, the laws prevail, albeit with notable distinctions: the two parameters of the log law are markedly distinct from their three-dimensional counterpart; further, one parameter (the von Kármán constant) is independent of the spectrum whereas the other (the offset of the log law) depends on the spectrum. Our results suggest that the classical theory of scaling in wall-bounded turbulence is incomplete wherein a key missing element is the link with the turbulent spectrum.

Long-term venous access device use in treatment of malignancies: experience from a government hospital in Eastern India

Long-term venous access catheters are very useful for administration of chemotherapy and other drug infusions in patients with haematological malignancies. But their use in government hospitals is still restricted. This study aimed to audit the surgical and infective complications of the vascular access devices which we have used for last three years in patients of haematological malignancies. We also tried to identify risk factors associated with higher infective and other complications.

Associations between pollen counts, pollutants, and asthma-related hospital admissions in a high-density Indian metropolis

BACKGROUND

The seasonal pattern of asthma-related hospitalization has often been correlated with ambient allergen/pollutant levels.

OBJECTIVE

To examine the relationship between asthma-related hospital admissions (ARHA) and outdoor pollen, spore, and pollutant levels for adult patients in a densely populated Indian megacity Kolkata.

METHODS

ARHA data were obtained from two major teaching hospitals of the city. Pollen and spores causing allergic sensitization were identified by skin prick tests (SPTs) among respiratory allergic subjects (N = 1353). Outdoor concentrations of aeroallergens were determined using a Burkard sampler for five consecutive years (2004-2009). Levels of NO(2), SO(2), suspended particulate matters (SPMs), and respirable particulate matters (RPMs) were made available by West Bengal Pollution Control Board (WBPCB, Government of West Bengal). Poisson multivariate Poisson regression (with adjustments for overdispersion) was used to model the data. Results. We found that ARHA in Kolkata increased with predictable regularity in March and September, while remaining low in January and July. SPT showed highly positive skin reactions with grass/weed and palm pollens in respiratory allergic patients, while Aspergilli spores also evoked good sensitivity. In our regression model, the airborne pollen types, Cheno-Amaranthaceae and Cyperaceae, and the inorganic pollutant, SO(2) and RPM, were significantly associated with ARHA (p < .05).

CONCLUSION

ARHA in the megacity of Kolkata shows two seasonal peaks that can be correlated with outdoor grass/weed pollen and RPM concentrations. In contrast, the city's ambient fungal spore counts were not found to be significantly associated.

Family history tools in primary care: does one size fit all?

Family health history (FHH) has potential value in many health care settings. This review discusses the potential uses of FHH information in primary care and the need for tools to be designed accordingly. We developed a framework in which the attributes of FHH tools are mapped against these different purposes. It contains 7 attributes mapped against 5 purposes. In considering different FHH tool purposes, it is apparent that different attributes become more or less important, and that tools for different purposes require different implementation and evaluation strategies. The context in which a tool is used is also relevant to its effectiveness. For FHH tools, it is unlikely that 'one size fits all', although appreciation of different purposes, users and contexts should facilitate the development of different applications from single FHH platforms.

Triterpenoids from Schleichera oleosa of Darjeeling Foothills and Their Antimicrobial Activity

Two triterpenoids, taraxerone and tricadenic acid A were isolated from the methanol extract of the outer bark of Schleichera oleosa available in Darjeeling foothills. A preliminary study on their antimicrobial activities was also performed against some fungal and bacterial species. The structure of these compounds was determined by means of chemical characterisation and IR, NMR spectral data.

Triterpenoids from Psidium guajava with Biocidal Activity

In continuation of our studies on the phytochemical investigation of medicinal plants available in the foothills of Darjeeling and Teri, we report herein the isolation of two triterpenoids betulinic acid and lupeol from the leaf extract of Psidium guajava and their potential antimicrobial and phytotoxic activities. All the structures of the isolated compounds were confirmed by spectral (IR, NMR) analysis and by comparison with the literature reports.