Comparison of adsorption capacity of p-Cresol & p-Nitrophenol by activated carbon in single and double solute

Adsorption of p-Cresol and p-Nitrophenol by untreated activated carbon in single and multisolute solutions was carried out at 301 K and at controlled pH conditions. In acidic conditions, well below the pK(a) of both solutes, it was observed that the adsorbate solubility and the electron density of aromatic rings influenced the extent of adsorption by affecting the extent of London dispersion forces. The fitted parameters obtained from single-solute Langmuir equation show that Q(max) and the adsorption affinity of carbon for the compound with low pK(a) decrease more significantly. In higher solution pH conditions, on the other hand, it was found that electrostatic forces played a significant role on the extent of adsorption. The presence of another compound decreases Q(max) and the adsorption affinity of carbon for the principal compound. The effect of pH, on the carbon surface and on the solute molecules, must be considered. Adsorption of the solute at higher pH values was found to be dependent on the concentration of anionic form of the solute. The isotherm data were fitted to the Langmuir isotherm equation for both single and double solute solutions.

Remitting behaviour of Nepalese rural-to-urban migrants: Implications for theory and policy

This article uses data for Nepal to test contemporary hypotheses about the remitting behaviour and associated motives of rural-to-urban migrants and to consider the likely impact of such remittances on rural development. Possibilities for inheritance, degree of family attachment, likelihood of eventual return to place of origin and family investment in the education of the migrants are found to be significant influences on levels of remittances by Nepalese migrants. However, in Nepal, remittances do not seem to result in long-term capital investment in rural areas and so may not promote long-term development of these areas.

Genetic variability in cultivated common bean beyond the two major gene pools

It is generally accepted that two major gene pools exist in cultivated common bean (Phaseolus vulgaris L.), a Middle American and an Andean one. Some evidence, based on unique phaseolin morphotypes and AFLP analysis, suggests that at least one more gene pool exists in cultivated common bean. To investigate this hypothesis, 1072 accessions from a common bean core collection from the primary centres of origin, held at CIAT, were investigated. Various agronomic and morphological attributes (14 categorical and 11 quantitative) were measured. Multivariate analyses, consisting of homogeneity analysis and clustering for categorical data, clustering and ordination techniques for quantitative data and nonlinear principal component analysis for mixed data, were undertaken. The results of most analyses supported the existence of the two major gene pools. However, the analysis of categorical data of protein types showed an additional minor gene pool. The minor gene pool is designated North Andean and includes phaseolin types CH, S and T; lectin types 312, Pr, B and K; and mostly A5, A6 and A4 types alpha-amylase inhibitor. Analysis of the combined categorical data of protein types and some plant categorical data also suggested that some other germplasm with C type phaseolin are distinguished from the major gene pools.

Osmoregulative capacity in birdseed millet under conditions of water stress. I. Variation in Setaria italica and Panicum miliaceum

Experiments involving 14 accessions of Panicum miliaceum L. (Proso millet) and 11 accessions of Setaria italica L. (Foxtail millet) have demonstrated variability in the degree of osmoregulative capacity among these accessions. Birdseed millet is generally claimed to be sensitive to drought stress, apparently because of a shallow root system. Accessions with high osmoregulative capacity demonstrate at least some drought tolerance. Osmoregulative capacity was measured on flag leaves of headed millet plants in pots undergoing water stress in a controlled environment chamber. Osmoregulative capacity was determined from the relationship between osmotic potential and leaf water potential; and the logarithmic relationship between osmotic potential and relative water content. The group of accessions of S. italica showed an overall level of osmoregulative capacity which was greater than that observed for the group of P. miliaceum accessions. Four accessions of S. italica (108042, 108463, 108541 and 108564) and one accession of P. miliaceum (108104) demonstrated high osmoregulative capacity. Differences of 1.05 MPa or more between observed and estimated osmotic potential were found at relative water contents of 80 % among these accessions. The extent of osmoregulative capacity was associated with osmotic potential at full turgor and the rate of decline in osmotic potential as leaf water potentail declined.

Effect of fertilizer placement on nitrogen loss from sugarcane in tropical Queensland

This paper reports on the fate of nitrogen (N) in a first ratoon sugarcane (Saccharum officinarum L.) crop in the wet tropics of Queensland when urea was either surface applied or drilled into the soil 3-4 days after harvesting the plant cane. Ammonia volatilization was measured with a micrometeorological method, and fertilizer N recovery in plants and soil, to a depth of 140 cm, was determined by mass balance in macroplots with N labelled urea 166 and 334 days after fertilizer application. The bulk of the fertilizer and soil N uptake by the sugarcane occurred between fertilizing and the first sampling on day 166. Nitrogen use efficiency measured as the recovery of labelled N in the plant was very low. At the time of the final sampling (day 334), the efficiencies for the surface and subsurface treatments were 18.9% and 28.8%, respectively. The tops, leaves, stalks and roots in the subsurface treatment contained significantly more fertilizer N than the corresponding parts in the surface treatment. The total recoveries of fertilizer N for the plant-trash-soil system on day 334 indicate significant losses of N in both treatments ( 59.1% and 45.6% of the applied N in the surface and subsurface treatments, respectively). Drilling the urea into the soil instead of applying it to the trash surface reduced ammonia loss from 37.3% to 5.5% of the applied N. Subtracting the data for ammonia loss from total loss suggests that losses by leaching and denitrification combined increased from 21.8% and 40.1% of the applied N as a result of the change in method of application. While the treatment resulted in increased denitrification and/or leaching loss, total N loss was reduced from 59.1% to 45.6%, ( a saving of 13.5% of the applied N), which resulted in an extra 9.9% of the applied N being assimilated by the crop.

Conditional simulation of random fields by successive residuals

This paper presents a new approach to the LU decomposition method for the simulation of stationary and ergodic random fields. The approach overcomes the size limitations of LU and is suitable for any size simulation. The proposed approach can facilitate fast updating of generated realizations with new data, when appropriate, without repeating the full simulation process. Based on a novel column partitioning of the L matrix, expressed in terms of successive conditional covariance matrices, the approach presented here demonstrates that LU simulation is equivalent to the successive solution of kriging residual estimates plus random terms. Consequently, it can be used for the LU decomposition of matrices of any size. The simulation approach is termed conditional simulation by successive residuals as at each step, a small set (group) of random variables is simulated with a LU decomposition of a matrix of updated conditional covariance of residuals. The simulated group is then used to estimate residuals without the need to solve large systems of equations.

Thermolysin activates equine lamellar hoof matrix metalloproteinases

Cultured equine lamellar hoof explants secrete the pro-enzymes matrix metalloproteinse-2 (MMP-2, 72 kDa) and MMP-2 (92 kDa). Untreated explants remained intact tested on a calibrated force transducer, but when treated with an NIMP activator, developed in-vitro laminitis, separating at the dermal-epidermal junction. Explants treated with the bacterial protease thermolysin separated dose-dependently; this was accompanied by activation of both MMP-2 and -9. Thermolysin-mediated NIP activation did not occur in a cell-free system and was not inhibited by the addition of the MMP inhibitor and batimastat. These findings suggest that thermolysin-mediated gelatinase activation is not dependent on membrane-bound matrix metalloproteinase (MT-MMP) activation, providing further evidence that bacteria can produce potent MMP activators that probably facilitate host invasion. (C) 2002 Harcourt Publishers Ltd.

How well do general practitioners deliver palliative care? A systematic review

General practitioners (GPs) deliver the majority of palliative care to patients in the last year of life. This article seeks to examine the nature of GP care, perceptions of the GPs themselves and others of that care, the adequacy of palliative care training, issues relating to accessibility of GPs to palliative care patients, and strategies that may be of use in encouraging more effective delivery of palliative care by GPs. Medline and PubMed databases from 1966 to 2000 were searched, and 135 references identified. Sixty-six of these described studies relevant to GP palliative care. GPs value this part of their work. Most of the time, patients appreciate the contribution the GP makes to palliative care particularly if the GP is accessible, takes time to listen, allows patient and carer to ventilate their feelings, and is seen to be making efforts made regarding symptom relief. However, reports from bereaved relatives suggest that palliative care is performed less well in the community than in other settings. GPs express discomfort about their competence to perform palliative care adequately. They tend to miss symptoms which are not treatable by them, or which are less common. However, with appropriate specialist support and facilities, GPs have been shown to deliver sound and effective care. GP comfort working with specialist teams increases with exposure to this form of patient management, as does the understanding of the potential other team members have in contributing to the care of the patient. Formal arrangements engaging GPs to work with specialist teams have been shown to improve functional outcomes, patient satisfaction, improve effective use of resources and improve effective physician behaviour in other areas of medicine. Efforts by specialist services to develop formal involvement of GPs in the care of individual patients, may be an effective method of improving GP palliative care skills and appreciation of the roles specialist services can play.

Enhanced quantitative resistance to Leptosphaeria maculans conferred by expression of a novel antimicrobial peptide in canola (Brassica napus L.)

The novel antimicrobial peptide MiAMP1, originally isolated from the seeds of Macadamia integrifolia, was constitutively expressed in transgenic tobacco and canola plants to test its effect on disease resistance. Analysis of plants transformed with 35S-MiAMP1 construct by northern and western blot analyses demonstrated the presence of MiAMP1 mRNA and the mature peptide in the transgenic plants. The MiAMP1 purified from the leaves of transgenic plants was biologically active with the same in vitro antifungal activity as native MiAMP1 purified from the seeds of macadamia. The effect of MiAMP1 expression on the economically important canola pathogen Leptosphaeria maculans (causal agent of blackleg disease) was evaluated in comparison with an untransformed control line and an azygous segregant derived from one of the transgenic lines. Lesion development on the cotyledons of the inoculated canola seedlings was significantly reduced in the T-2 progeny of seven independently transformed transgenic lines. These results suggested that, transgenic canola expressing MiAMP1 may be useful for the management of blackleg disease.

Expression of Heparan Sulphate N-deacetylase/N-sulphotransferase by Vascular Smooth Muscle Cells

Heparan sulphate is an important mediator in determining vascular smooth muscle cell (SMC) phenotype. The sulphation pattern of the heparan sulphate chains is critical to their function. We have examined the initial step in the biosynthesis of the sulphated domains mediated by the enzyme heparan sulphate N-deacetylase/N-sulphotransferase (NDST). Rabbit aortic SMC in primary culture exhibited NDST enzyme activity and expressed NDST-1 in their Golgi apparatus, with maximal expression in SMC 2 days after dispersal in primary culture confirmed by Western blot analysis. Endothelial cells, macrophages and fibroblasts expressed NDST-1 but had generally less intense staining than SMC, although SMC expression decreased with culture. The uninjured rat aorta also showed widespread expression of NDST-1. After balloon de-endothelialisation, NDST-1 could not be detected in SMC of the neointima in the early stages of neointimal formation, but was re-expressed at later time points (after 12 weeks). In human coronary arteries, SMC of the media and the diffuse intimal thickening expressed NDST-1, while SMC in the atherosclerotic plaque were negative for NDST-1. We conclude that SMC may regulate their heparan sulphate sulphation at the level of expression of the enzyme heparan sulphate NDST in a manner related to their phenotypic state.