1,318 research outputs found
Microrheological Characterisation of Anisotropic Materials
We describe the measurement of anisotropic viscoelastic moduli in complex
soft materials, such as biopolymer gels, via video particle tracking
microrheology of colloid tracer particles. The use of a correlation tensor to
find the axes of maximum anisotropy, and hence the mechanical director, is
described. The moduli of an aligned DNA gel are reported, as a test of the
technique; this may have implications for high DNA concentrations in vivo. We
also discuss the errors in microrheological measurement, and describe the use
of frequency space filtering to improve displacement resolution, and hence
probe these typically high modulus materials.Comment: 5 pages, 5 figures. Replaced after refereeing/ improvement. Main
results are the same. The final, published version of the paper is here
http://link.aps.org/abstract/PRE/v73/e03190
Factors' Employment Absorption, Growth and Income Distribution through Foreign Trade: Pakistan's Case
Despite the recent migration of Pakistan's labour to the
Middle East countries, Pakistan is still characterized as a
labour-abundant and capital-scarce developing country. As such, it is
important that Pakistan's production structure should be such as to
employ greater labour and lesser capital per unit of output in the
different sectors of the economy. To provide pertinent information to
the policy makers in this regard, we here try to estimate how much of
labour and capital are employed and absorbed per unit of output in
Pakistan's internationally traded goods
Intestinal obstruction in adults at the Aga Khan University Hospital
During the period January, 1987 to June, 1991, 208 adults with mechanical bowel obstruction were managed at The Aga Khan University Hospital (AKUH). Post-operative adhesions accounted for 34% of the cases and were the most frequent cause of intestinal obstruction. External hemia (16%), malignancy (13.5%) and tuberculous stricture (10%) were the next most frequent causes. The predominance of adhesive intestinal obstruction at AKUH shows a trend towards a Western disease pattern. Socioeconomic status was a significant determinant of the cause of obstruction. The proportion of self paying to welfare patients was significantly lower in tuberculous obstruction as compared with adhesive or malignant obstruction and in obstruction caused by hernia as compared with that due to malignant disease (P \u3c 0.05). The present study demonstrates the synchronal occurrence of old and new diseases in a population and points towards the epidemiological transition which is affecting urban areas in the developing world
Antibiotic susceptibility pattern and multiple antibiotic resistances (MAR) calculation of extended spectrum β- lactamase (ESBL) producing Escherichia coli and Klebsiella species in Pakistan
The aim of this study was to check for the antibiotic susceptibility pattern and multiple antibiotic resistances (MAR) of extended spectrum β-lactamase (ESBL) producing Escherichia coli and Klebsiella species. All methods used in this study were according to the standard criteria of NCCLs. It was shown that there was high rate of resistance, which was alarming for health practitioners of Pakistan.Key words: Antibiotics, multiple antibiotic resistances (MAR), extended spectrum β-lactamase (ESBL)
The human genome sequence: impact on health care
The recent sequencing of the human genome, resulting from two independent global efforts, is poised to revolutionize all aspects of human health. This landmark achievement has also vindicated two different methodologies that can now be used to target other important large genomes. The human genome sequence has revealed several novel/surprising features notably the probable presence of a mere 30-35,000 genes. In depth comparisons have led to classification of protein families and identification of several orthologues and paralogues. Information regarding non-protein coding genes as well as regulatory regions has thrown up several new areas of research. Although still incomplete, the sequence is poised to become a boon to pharmaceutical companies with the promise of delivering several new drug targets. Several ethical concerns have also been raised and need to be addressed in earnest. This review discusses all these aspects and dwells on the possible impact of the human genome sequence on human health, medicine and also health care delivery system
The morphology and bioactivity of the rice field cyanobacterium <i>Leptolyngbya</i>
The genus Leptolyngbya comprises filamentous cyanobacteria that are important in rice fields. In the rhizosphere, cyanobacteria produce a variety of secondary metabolites such as auxins that are important in agriculture soil performance. To assess this, Leptolyngbya strain MMG-1, was isolated from the rhizosphere of rice plants and described. For this, the morphology of this strain was studied by light microscopy as well as by confocal laser scanning microscopy. Besides, the ability of this strain to synthesize an auxin-like bioactive compound was demonstrated under various culture conditions (different amounts of tryptophan; pH; different alternating light:dark periods; duration of the incubation). The auxin-like compound was extracted from the culture of Leptolyngbya strain MMG-1 and identified as indole-3-acetic acid (IAA) by thin layer chromatography (TLC) as well as by high performance liquid chromatography (HPLC). Our results showed that the strain required the precursor L-tryptophan for the synthesis of IAA. Leptolyngbya strain MMG-1 accumulated IAA intracellularly. The IAA secreted by Leptolyngbya strain MMG-1 was significantly correlated with the initial concentration of L-tryptophan in the medium, as well as with the duration of the incubation. The bioactivity of the secreted IAA was determined by its effect on the rooting pattern of Pisum sativum seedlings. The culture supernatant of Leptolyngbya strain MMG-1 stimulated the seedling lateral rooting, while it decreased root length. Hence, rhizospheric Leptolyngbya produced auxin under different conditions and affected the plants rooting pattern
Antibacterial and Cytotoxic Activities of Acacia nilotica Lam (Mimosaceae) Methanol Extracts Against Extended Spectrum Beta-Lactamase Producing Escherichia coli and Klebsiella Species
Purpose: To investigate lysates from Acacia nilotica pods for their antimicrobial and cytotoxic activities against a variety of extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae as well as methicillin resistant Staphylococci aureus (MRSA).Methods: ESBLs-producing E. coli and Klebsiella spp were isolated from clinical and environmental specimens and incubated with Acacia nilotica pod lysates. The bactericidal activity and cytotoxic effects of the lysates were evaluated while fast protein liquid chromatography (size exclusion FPLC) was used to identify the various compounds showing bactericidal activity.Results: The lysates showed remarkable bactericidal properties, killing almost 100 % of the bacteria they were tested against, including neuropathogenic Escherichia coli, MRSA, and Klebsiella spp. The bactericidal activity was heat-resistant and showed minimal cytotoxic effects on human brain microvascular endothelial cells. FPLC revealed eight peaks, with three of them representing compounds that had maximum bactericidal activity against all the tested isolates, but showed < 30 % host cell cytotoxicity.Conclusion: The lysate of Acacia nilotica pods is a potentially good candidate for the therapy of antibacterial-resistant bacteria, and would therefore require further studies.Keywords: Acacia nilotica, ESBLs, MRSA, E. coli, Klebsiella, Antibacterial resistance, Cytotoxicit
Influence of an Engineered Notch on the Electromagnetic Radiation Performance of NiTi Shape Memory Alloy
This work explores the influence of a pre-engineered notch on the electromagnetic radiation (EMR) parameters in NiTi shape memory alloy (SMA) during tensile tests. The test data showed that the EMR signal fluctuated between oscillatory and exponential, signifying that the specimen’s viscosity damping coefficient changes during strain hardening. The EMR parameters, maximum EMR amplitude, and average EMR energy release rate remained constant initially but rose sharply with the plastic zone radius with progressive loading. It was postulated that new Frank–Read sources permit dislocation multiplication and increase the number of edge dislocations participating in EMR emissions, leading to a rise in the value of EMR parameters. The study of the correlation between EMR emission parameters and the plastic zone radius before the crack tip is a vital crack growth monitoring tool. An analysis of the interrelationship of the EMR energy release rate at fracture with the elastic strain energy release rate would help develop an innovative approach to assess fracture toughness, a critical parameter for the design and safety of metals. The microstructural analysis of tensile fractures and the interrelation between deformation behaviours concerning the EMR parameters offers a novel and real-time approach to improve the extant understanding of the behaviour of metallic materials
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