256 research outputs found

    The use of isoenzymes in the study of germination, development and breeding of legumes

    Get PDF
    Amylase activities and patterns were compared in extracts from mature seeds and from different parts of seedlings at various stages of seed germination of various varieties of different legume species. Apart from soyabean, all varieties had low levels of amylase activities in extracts from mature seeds, while the former had a remarkably high level. Amylase activities and the number of bands increased during seed germination and showed time and tissue specifity. The extracts from cotyledons had the highest activities and the largest number of bands as compared to that of the various parts of embryonic axes. Amylase activities and patterns had time specific changes during the various stages of seed development of the 7 varieties of different legume species studied. All the different varieties showed changes in zymogram patterns and decreased amylase activity during seed development, except soyabean where amylase activity remained high at all stages. The different components of amylase were characterised in pea (var. Feltham First). One band of a -amylase activity, restricted to the cotyledons, was present in the middle stages of seed development only, then reappeared at the third day of seed germination. The embryonic axes β -amylase activity decreased as the seed developed, to reach zero level in mature seeds, and reappearred during seed germination. The reverse sequence occurred for the cotyledonary β -amylase. The pea a -amylase was partially purified using ethanol precipitation, glycogen complex and hydroxyapatite column chromatography. The purified protein had three major bands with few faint bands on the SDS polyacrylamide gel. The embryonic axes β -amylase of pea was partially purified using the conventional method, ammonium sulphate precipitation, ion exchange chromatography and gel filtration. The purified protein contained two thick bands and many faint bands on the SDS polyacrylamide gel. The zymogram patterns of phosphorylase, EST, GDH, GOT, LDH, ADH and MDH were investigated during seed development of various varieties of different legume species. The most noticeable changes as the seeds developed were the decrease in activities and number of bands of EST in pea and soyabean, shift in GDH activities between isoenzyme forms in pea (var. English Wonder), increase in GDH activities and number of bands in dwarf French bean and soyabean and increase in activities and number of bands of MDH in pea (var. Feltham First)

    Optimal control of diabetes

    Get PDF
    This thesis considers optimal control problems related to one of the major global health problems, Diabetes. We adopt a comprehensive dynamic model of the blood glucose regulatory system and show how it can be readily fitted to individuals. Based on this, we develop a composite dynamic model for simulating the effects of exercise and subcutaneous insulin injections on the blood glucose regulatory system. We then determine that optimal treatment regimens on the basis of the composite model

    Metallothionein induction reduces caspase-3 activity and TNFα levels with preservation of cognitive function and intact hippocampal neurons in carmustine-treated rats

    Get PDF
    Hippocampal integrity is essential for cognitive functions. On the other hand, induction of metallothionein (MT) by ZnSO4 and its role in neuroprotection has been documented. The present study aimed to explore the effect of MT induction on carmustine (BCNU)-induced hippocampal cognitive dysfunction in rats. A total of 60 male Wistar albino rats were randomly divided into four groups (15/group): The control group injected with single doses of normal saline (i.c.v) followed 24 h later by BCNU solvent (i.v). The second group administered ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v, once) then BCNU solvent (i.v) after 24 h. Third group received BCNU (20 mg/kg, i.v, once) 24 h after injection with normal saline (i.c.v). Fourth group received a single dose of ZnSO4 (0.1 µmol/10 µl normal saline, i.c.v) then BCNU (20 mg/kg, i.v, once) after 24 h. The obtained data revealed that BCNU administration resulted in deterioration of learning and short-term memory (STM), as measured by using radial arm water maze, accompanied with decreased hippocampal glutathione reductase (GR) activity and reduced glutathione (GSH) content. Also, BCNU administration increased serum tumor necrosis factor-alpha (TNFα), hippocampal MT and malondialdehyde (MDA) contents as well as caspase-3 activity in addition to histological alterations. ZnSO4 pretreatment counteracted BCNU-induced inhibition of GR and depletion of GSH and resulted in significant reduction in the levels of MDA and TNFα as well as the activity of caspase-3. The histological features were improved in hippocampus of rats treated with ZnSO4 + BCNU compared to only BCNU-treated animals. In conclusion, MT induction halts BCNU-induced hippocampal toxicity as it prevented GR inhibition and GSH depletion and counteracted the increased levels of TNFα, MDA and caspase-3 activity with subsequent preservation of cognition

    Effect of Shape, Orientation and Aging of a Plastic Greenhouse Cover on the Degradation Rate of the Optical Properties in Arid Climates

    Get PDF
    In arid climates, the optical properties of plastic-covered greenhouses deteriorate very quickly. To examine the effect of greenhouse shape and orientation on the degradation rate of cover optical properties, four greenhouse prototypes were constructed in two shapes (duo-pitched roof and tunnel), covered with a 200  m thick low-density polyethylene film. Two types were oriented in the North–South direction, the other two in the East–West direction, and all were exposed for one year to an arid climate. Samples were taken from the different surfaces of each cover for testing. The total transmittance (Ts) and reflectance (Rs) of the samples were measured and averaged to obtain the whole cover properties (T and R). Measurements were carried out periodically every 30 days for the four prototypes. The degradation behavior of the optical properties of each cover surface (Ts, Rs) and the whole cover (T, R) was investigated for the four film covers during the exposure time. Results show that the degradation rate of Ts depends on the surface location and the cover orientation. Among the different surfaces of the four prototype covers, the maximum difference in the Ts value between the E and N surfaces for the tunnel cover oriented in the N–S direction was 15.5%. Although the variation of the Ts value among the different cover surfaces was found, the time dependences of the whole cover transmittance (T) for the four covers tested were almost similar. Accordingly, the shape and orientation of the small size greenhouses did not significantly affect the degradation rate of the cover optical properties. In the four covers tested, the reduction in the global solar radiation transmittance (T) was 27–31% after one-year exposure compared to the new film. Nonlinear correlation was developed to predict the degradation rate of the cover transmittance as a function of the accumulated solar irradiance

    Reflection and Transmission of an Incident Progressive Wave by Obstacles in Homogeneous Shallow Water

    Get PDF
    The influence of a suspended fixed obstacle on an incident progressive wave inside an ideal homogeneous shallow water is studied in two dimensions. The fluid occupies an infinite channel of a constant depth, and a fixed obstacle of a small horizontal extent is partially submerged without contact with the bottom of the channel. An asymptotic double series expansion for the solution is used. The procedure enables us to calculate analytic expressions for the local perturbations up to the second order. The results of the first-order approximation indicate that no reflections exist. The second-order approximation of the solution is found to be the superposition of a progressive wave and local perturbations. For approximations of order higher than two, a secular term which increases monotonically with time and distance appears in the expressions for the progressive wave. This unacceptable result is due to a certain aspects in the mathematical procedure used. For this reason, the procedure is modified by using a suitable transformation of variables which reduces the determination of the transmitted wave to the solution of the KdV equation. As an illustration, the special case of the incident uniform flow is considered and the stream lines of the resulting flow are drawn

    Pro-inflammatory and oxidative stress pathways which compromise sperm motility and survival may be altered by L-carnitine

    Get PDF
    The testis is an immunologically privileged organ. Sertoli cells can form a blood-testis barrier and protect sperm cells from self-immune system attacks. Spermatogenesis may be inhibited by severe illness, bacterial infections and chronic inflammatory diseases but the mechanism(s) is poorly understood. Our objective is to help in understanding such mechanism(s) to develop protective agents against temporary or permanent testicular dysfunction. Lipopolysaccaride (LPS) is used as a model of animal sepsis while L-carnitine (LCR) is used as a protective agent. A total of 60 male Swiss albino rats were divided into four groups (15/group). The control group received Saline; the 2nd group was given LCR (500 mg/kg i.p, once). The third group was treated with LPS (5 mg/kg i.p once) and the fourth group received LCR then LPS after three hours. From each group, five rats were used for histopathological examination. Biochemical parameters were assessed in the remaining ten rats. At the end of the experiment, animals were lightly anaesthetized with ether where blood samples were collected and testes were dissected on ice. Sperm count and motility were evaluated from cauda epididymis in each animal. Also, oxidative stress was evaluated by measuring testicular contents of reduced glutathione (GSH), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-HDG, the DNA adduct for oxidative damage) in testicular DNA. The pro-inflammatory mediator nitric oxide (NO) in addition to lactate dehydrogenase (LDHx) isoenzyme-x activity as an indicator for normal spermatozoal metabolism were assessed in testicular homogenate. Serum interlukin (IL)-2 level was also assessed as a marker for T-helper cell function. The obtained data revealed that LPS induced marked reductions in sperm's count and motility, obstruction in seminiferous tubules, hypospermia and dilated congested blood vessels in testicular sections concomitant with decreased testicular GSH content and LDHx activity. Moreover, the testicular levels of MDA, 8-HDG (in testicular DNA) and NO as well as serum IL-2 level were increased. Administration of LCR before LPS returned both sperm count and motility to normal levels. Also, contents of testicular GSH, MDA, 8-HDG and NO returned back to the corresponding control values. In addition, serum IL-2 level as well as histological abnormalities were markedly improved in LCR + LPS-treated rats. In conclusion, LPS increased proinflammatory and oxidative stress markers in the testis leading to a marked testicular dysfunction. L-carnitine administration ameliorates these effects by antioxidant and/or anti-inflammatory mechanisms suggesting a protective role against male infertility in severely infected or septic patients

    Acquired air-filled lung cysts in childhood: pathogenesis of cysts of diverse etiologies; nuances of management

    Get PDF
    Background Air-filled pulmonary parenchymal cysts (pneumatoceles/PCs) – a pathological condition – involving the lung parenchyma may be congenital or acquired. In children, acquired cases are often caused by staphylococcal pneumonias, but other etiologies may also cause PCs and lead to diagnostic confusion.Objectives The aim of this study was to examine the natural history and clinicopathologic features of noncongenital, nonstaphylococcal PCs in children.Patients and methods Four children with nonstaphylococcal PCs were included in this study. A full history, clinical examination, relevant radiological and pathological findings, surgical intervention where relevant, and follow-up were analyzed.Results The cases described represent acquired PCs: one occurred after infarction following cardiac surgery, another was a subpleural pulmonary bleb of inflammatory origin, and the remaining two were post-traumatic pseudocysts. The inflammatory-process bleb and the postinfarction cysts presented with pneumothorax. The postinfarction and post-traumatic PCs responded to observation. The pulmonary bleb was excised.Conclusion Our understanding of the clinicopathologic features and pathogenesis of many types of acquired PCs is incomplete. We propose that PC formation has a basis in destruction of the distal airways of the lung. Damaged tissue may act as a valve, and cause air-trapping, which leads to PC formation. Cysts arising after infarction or after trauma usually resolve on observation. Subpleural blebs may require excision because of nonresolution and recurrence of pneumothorax

    Assessment Of The Global Fallout Of Plutonium Isotopes In The Topsoil Of Qatar: Establishing A Baseline Concentrations Of 238pu, 239pu, And 240pu

    Get PDF
    A radio-analytical technique for determination of plutonium (Pu) isotopes in soil samples is tested against NIST and IAEA standard reference materials to determine its accuracy and precision for reliable results. The technique is then used in the investigation of 132 topsoil samples, collected from the natural environment of Qatar, to assess the effect of global fallout accumulation of these radionuclides in the region. Plutonium was sequentially leached form 1000 g of each soil sample using nitric and hydrochloric acids. The residual fine particles were separated by filtration and centrifuge. The solution was reduced to 1 ml by evaporation in dry oven and measured directly by CRC-ICP-MS/MS without prior chemical separation of Pu. The concentrations of 238Pu in the collected soil samples vary from < 0.026 - 0.058 fg/g (< 0.0160 - 0.0266 Bq/kg) with a mean value of 0.034 fg/g (0.0195 Bq/kg) and a median value of 0.032 fg/g (0.0195 Bq/kg). The concentrations of 239Pu fall in the range 5.67 - 166.09 fg/g (0.014 - 0.381 Bq/kg) with a mean value of 67.33 fg/g (0.154 Bq/kg) and a median value of 63.21 fg/g (0.145 Bq/kg). The concentrations of 240Pu fall in the range 1.48 - 28.21 fg/g (0.013 - 0.240 Bq/kg) with a mean value of 11.46 fg/g (0.098 Bq/kg) and a median value of 10.835 fg/g (0.093 Bq/kg). The isotopic and activity concentrations ratios of 238Pu/239Pu, 240Pu/239Pu, and 238Pu/239+240Pu can be used to identify the source. The main isotope ratios of 238Pu/239Pu in Qatari soils is (3.33 ± 1.02) x 10-4. A reported global and Chernobyl fallouts isotope ratio of 238Pu/239Pu are 1.77 x 10-4 and 4.3 x 10-3, respectively. The main isotope ratio of 240Pu/239Pu in Qatari soils is 0.1749 ± 0.0211. A reported global and Chernobyl fallouts isotope ratios of 240Pu/239Pu are 0.18-0.19 and 0.34-0.57, respectively. The average isotopic and activity ratios of 238Pu/239,240Pu in Qatari soils are (2.856 ± 0.881) x 10-4 and 0.0505 ± 0.0032, respectively. The activity ratio 238Pu/239+240Pu in releases from nuclear fuel reprocessing plants, nuclear tests, weapons grade, and Chernobyl fallout are about 0.25, 0.026, 0.014 and 0.47, respectively. Accordingly, it is difficult to identify the source, but it may be due to the contribution of more than one source. The most probable sources are both Chernobyl fallout of Pu isotopes and several decades of fallout Pu accumulation due to nuclear weapons testing. Novel Aspect New data base was established for the concentration and isotope ratios of Pu isotopes (238Pu, 239Pu, and 240Pu) in Qatar topsoil.qscienc

    Glycerol: An unexpected major metabolite of energy metabolism by the human malaria parasite

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Malaria is a global health emergency, and yet our understanding of the energy metabolism of the principle causative agent of this devastating disease, <it>Plasmodium falciparum</it>, remains rather basic. Glucose was shown to be an essential nutritional requirement nearly 100 years ago and since this original observation, much of the current knowledge of <it>Plasmodium </it>energy metabolism is based on early biochemical work, performed using basic analytical techniques (e.g. paper chromatography), carried out almost exclusively on avian and rodent malaria. Data derived from malaria parasite genome and transcriptome studies suggest that the energy metabolism of the parasite may be more complex than hitherto anticipated. This study was undertaken in order to further characterize the fate of glucose catabolism in the human malaria parasite, <it>P. falciparum</it>.</p> <p>Methods</p> <p>Products of glucose catabolism were determined by incubating erythrocyte-freed parasites with D-[1-<sup>13</sup>C] glucose under controlled conditions and metabolites were identified using <sup>13</sup>C-NMR spectroscopy.</p> <p>Results</p> <p>Following a 2 h incubation of freed-<it>P. falciparum </it>parasites with 25 mM D-[1-<sup>13</sup>C] glucose (<it>n </it>= 4), the major metabolites identified included; [3-<sup>13</sup>C] lactate, [1,3-<sup>13</sup>C] glycerol, [3-<sup>13</sup>C] pyruvate, [3-<sup>13</sup>C] alanine and [3-<sup>13</sup>C] glycerol-3-phosphate. Control experiments performed with uninfected erythrocytes incubated under identical conditions did not show any metabolism of D-[1-<sup>13</sup>C] glucose to glycerol or glycerol-3-phosphate.</p> <p>Discussion</p> <p>The identification of glycerol as a major glucose metabolite confirms the view that energy metabolism in this parasite is more complex than previously proposed. It is hypothesized here that glycerol production by the malaria parasite is the result of a metabolic adaptation to growth in O<sub>2</sub>-limited (and CO<sub>2 </sub>elevated) conditions by the operation of a glycerol-3-phosphate shuttle for the re-oxidation of assimilatory NADH. Similar metabolic adaptations have been reported previously for other microaerobic/anaerobic organisms, such as yeast, rumen protozoa and human parasitic protozoa.</p> <p>Conclusion</p> <p>These data highlight the need to re-evaluate the carbon and redox balance of this important human pathogen, ultimately leading to a better understanding of how the parasite is able to adapt to the variable environments encountered during parasite development and disease progression.</p

    Covering Materials Incorporating Radiation-Preventing Techniques to Meet Greenhouse Cooling Challenges in Arid Regions: A Review

    Get PDF
    Cooling greenhouses is essential to provide a suitable environment for plant growth in arid regions characterized by brackish water resources. However, using conventional cooling methods are facing many challenges. Filtering out near infra-red radiation (NIR) at the greenhouse cover can significantly reduce the heating load and can solve the overheating problem of the greenhouse air. This paper is to review (i) the problems of using conventional cooling methods and (ii) the advantages of greenhouse covers that incorporate NIR reflectors. This survey focuses on how the cover type affects the transmittance of photosynthetically active radiation (PAR), the reflectance or absorptance of NIR and the greenhouse air temperature. NIR-reflecting plastic films seem to be the most suitable, low cost and simple cover for greenhouses under arid conditions. Therefore, this review discusses how various additives should be incorporated in plastic film to increase its mechanical properties, durability and ability to stand up to extremely harsh weather. Presently, NIR-reflecting covers are able to reduce greenhouse air temperature by no more than 5°C. This reduction is not enough in regions where the ambient temperature may exceed 45°C in summer. There is a need to develop improved NIR-reflecting plastic film covers
    corecore