Regulation of water and electrolyte metabolism during dehydration and rehydration in camels

The present study was undertaken to examine the effect of severe dehydration and rapid rehydration in electrolytes and body fluids homeostasis on the arabian camel (Camelus dromedarius), and to find out which pathway is responsible for the secretion of aldosterone in the dehydrated camel; either the renin-angiotensin axis or ACTH axis. In the first experiment ten dromedary camels were studied for a total of 29 days; 7 days under control conditions, 15 days of water deprivation and 7 days of rehydration in Bureidah (Saudi Arabia) during summer, 1996. Plasma electrolyte concentrations, plasma osmolality, packed cell volume (PCV), blood hemoglobin concentrations, plasma concentrations of glucose, creatinine, blood urea nitrogen (BUN), total protein, plasma renin activity (PRA), angiotensin II, aldosterone, arginine-vasopressin (AVP), adrenocorticotropic hormone (ACTH) and cortisol concentrations were determined during both periods. During the second trial adrenocorticotropic hormone (ACTH) and enalapril, an angiotensin-converting enzyme inhibitor (ACE-I), were utilized in two separate experiments during dehydration and control (hydration) periods. Enalapril (0.2 [mu]g/kg) induced a sharp decrease in plasma (Na+] and an increase in plasma (K+] concentrations (P \u3c 0.05) in the dehydrated camels but not in the control camels;Plasma osmolality decreased significantly in both dehydrated and control camels after ACE-I administration. ACE-I induced a sharp decrease in plasma angiotensin II and aldosterone concentrations (P \u3c 0.05) in the dehydrated camels. In the control camels however, ACE-I induced a decrease in plasma aldosterone concentrations but not in plasma angiotensin II. Plasma renin activity (PRA) increased significantly in the dehydrated camels. In the second experiment, 0.4 IU/kg ACTH administration had no significant effect on plasma electrolytes and osmolality on the dehydrated and control camels. The administration of ACTH induced a sharp increase in plasma cortisol concentrations in the dehydrated and control camels. Plasma aldosterone concentrations however, increased only in the dehydrated camels. The present study clearly shows that both angiotensin II and ACTH stimulate aldosterone secretion during dehydration in camels. However, due to the parallel increase in PRA, plasma angiotensin II and plasma aldosterone in dehydrated camels without any parallel changes in plasma cortisol or ACTH, the effect of angiotensin II on aldosterone secretion seems to be dominant over ACTH

A study on the fundamental behaviour of soil-structure interaction and mitigating effects of EPS geofoam inclusions in integral abutment bridges

The traditional construction procedure of bridges involves the use of expansion joints to allow for unrestricted superstructure movements against the temperature induced deformations. However, expansion joints have been demonstrated to be vulnerable to deterioration thus requiring frequent and costly maintenance. In that regard, the Integral Abutment Bridge (IAB) system presents an attractive alternative to overcome such problems. In addition to the advantages achieved by eliminating the expansion joints, the IABs have desirable structural performance and offer simple and rapid construction procedures. In the last few decades, IABs have been increasingly utilised in many countries around the world. Nowadays, the integral and semi-integral abutment bridges are becoming the first choice in the construction of bridges. Nevertheless, the IABs yet have their unique problems that ensue from the regular expansions and contractions (including shrinkage) in the superstructure. These problems have negated some of the advantages of IABs and restricted their use. The complex soil-structure interaction mechanism in IABs has made it difficult for engineers to find the appropriate solution to address the approach issues in this type of bridges. Adopted remedy measures include the use of run-on concrete approach slabs, heavily compacted approach fill, compressible inclusion between the soil and the abutment, and self-stable MSE approach fill with gap separation between the abutment and the MSE fill. However, no single solution can adequately address the broad array of IAB cases, each under a different setting, across the world. The present thesis extends current insights on the soil-structure interaction of IABs, with particular emphasis on the effects on the soil settlement and the lateral pressure at the integral abutment approach. The aim is to provide a sound basis to develop potential or improve current mitigating solutions. The thesis then investigates using EPS geofoam as a mitigating solution through a study of soil-EPS and EPS–abutment interactions. A combination of physical modelling and numerical analyses has been utilized to perform these investigations. In the thesis, a comprehensive review of the existing practices in dealing with the soilstructure interaction effects in IABs has been undertaken. A novel analytical solution is developed to estimate the passive earth pressure based on an earlier hypothesis of Terzaghi. This solution provides an efficient tool to calculate the passive earth pressure which represents a fundamental input in the estimation of earth pressure in IABs

Erythrocyte osmotic fragility and blood indices in the one-humped camel (Camelus dromedarius) : correlations with age and sex

http://www.worldcat.org/oclc/3400175

Vegetation analysis in the Rawdhat Om Al-Khefas, Central Saudi Arabia

Abstract: Rawdhats are unique habitats in the hyper-arid region of Central Saudi Arabia. However, its vegetation is under constant threat of heavy anthropogenic activities. The present study identifies the major plant communities and gradients of plant compositional change within the Rawdhat Om AlKhefas. Classification and of vegetation data by TWINSPAN displayed seven clear vegetation groups, each with specific indicator species. The seven vegetation groups were confirmed by detrended correspondence analysis (DCA). The direct canonical correspondence analysis (CCA) was used to assess the vegetation-soil relationships. The main soil variables controlling the separation of the vegetation groups on the first two axes of CCA are soil texture, pH and CaCO 3 . However, these factors contributed not more than 30.5% of total species data variances along the three axes of CCA. The tree layer represented by Acacia tortilis subsp. tortilis and Ziziphus nummularia is positively correlated with the proportion of soil silt and clay, while the communities characterized by Rhazya stricta, Lasiurus scindicus and Lycium shawii are positively correlated with the proportion of soil sand. The findings of this study suggests that the further research are needed to evaluate the human impact on the vegetation dynamics within the rawdhats

Studies on the feasibility of targeting cytotoxics to melanoma

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN013249 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

PHARMACOGNOSY AND NEW TRENDS OF B. PHARM SYLLABI

Objective: The Pharmacy profession has evolved from its conventional drug focused basis to an advanced patient focused basis over the years. Accordingly, many universities worldwide are modifying their Curricula in order to reflect this change.Methods: This paper investigates and compares the syllabi of B. Pharm for different Universities in Africa and Asia. Pharmacy Syllabi of the included Universities is presented in the form of Sectors, i.e. Pharmaceutical Sciences, Clinical Pharmacy, Biomedical, Training and University Requirements. Percentage analysis of credit hours allotted to courses of each Sector performed with special emphasis on courses of Pharmacognosy and Pharmaceutical Science in comparison to courses of Clinical Pharmacy.There is a substantial decrease in teaching hours of Pharmaceutical Sciences, particularly Pharmacognosy within the B. Pharm Curricula of some of the included Universities at the expense of including more courses in Clinical Pharmacy.Results: Pharmacists are scientists as well as clinicians, and basic science knowledge such as pharmaceutical sciences, give pharmacy graduates critical scientific foundations, in this regard, the reduction in pharmaceutical sciences content in a pharmacy curriculum may compromise the competence of pharmacy graduates, as the drug experts from the basic science level to the clinical level.Conclusion: The impact of reducing pharmaceutical science content, may compromise the Pharmacist ability to assume certain duties in the countries included in the study. This in consideration that Clinical Pharmacy is not widely practiced in the investigated countries and its application is limited compared to other job opportunities available for Pharmacy graduates of these countries such as Community Pharmacy, Pharmaceutical Industries, marketing and sales and utilization of natural resources of medicinal plants by research and development units.Recommendations on how to avoid such decrease in teaching hours of Pharmaceutical Courses and fulfil the job requirements in the above countries are given

Geotechnical design practices and soil-structure interaction effects of an integral bridge system : a review

Integral bridges are a class of bridges with integral or semi-integral abutments, designed without expansion joints in the bridge deck of the superstructure. The significance of an integral bridge design is that it avoids durability and recurring maintenance issues with bridge joints, and maybe bearings, which are prevalent in traditional bridges. Integral bridges are less costly to construct. They require less maintenance and therefore cause less traffic disruptions that incur socio-economic costs. As a consequence, integral bridges are becoming the first choice of bridge design for short-to-medium length bridges in many countries, including the UK, USA, Europe, Australia, New Zealand and many other Asian countries. However, integral bridge designs are not without challenges: issues that concern concrete creep, shrinkage, temperature effects, bridge skew, structural constraints, as well as soil–structure interactions are amplified in integral bridges. The increased cyclic soil–structure interactions between the bridge structure and soil will lead to adverse soil ratcheting and settlement bump at the bridge approach. If movements from bridge superstructures were also transferred to pile-supported substructures, there is a risk that the pile–soil interactions may lead to pile fatigue failure. These issues complicate the geotechnical aspects of integral bridges. The aim of this paper is to present a comprehensive review of current geotechnical design practices and the amelioration of soil–structure interactions of integral bridges

Application of engineered compressible inclusions to mitigating soil-structure interaction issues in integral bridge abutments

The thermally induced cyclic loading on integral bridge abutments causes soil deformation and lateral stress ratcheting behind the abutment wall due to the expansion and contraction of the bridge deck. The forward and backward movements of the abutment in response to the expansion/contraction of the bridge deck lead to the formation of settlement trough and surface heaving, frequently creating a bump at the bridge approach and increasing the lateral earth pressure behind the abutment. Measures to reduce the bump at the bridge approach, including several treatment methods, such as compaction of selected backfill materials, grout injection, installation of approach slab, and using a layer of compressible inclusion material behind the abutment were proposed. However, these guidelines still lack sufficient design details and there are limited experimental findings to validate design assumptions. In this paper, the use of engineered compressible materials to alleviate the lateral earth pressure ratcheting and settlement at the bridge approach is investigated. The comparative study is presented for the soil-inclusion, material-structure and soil-structure interactions for an integral bridge under three different backfill conditions, i.e. (a) sand, (b) sand and EPS geofoam, and (c) sand and Infinergy. The study was conducted in a special large-scale test chamber with a semi-scale abutment to gain better insights into the soil-structure interaction (SSI). The kinematics and rearrangement of the soil during the cyclic loading have been investigated to identify the mitigating effects of compressible inclusions. The comparative study indicates that both compressible inclusions perform comparatively well, however, Infinergy is a better alternative than the medium-density EPS geofoam, as it works more effectively to reduce the backfill settlement and heaving as well as soil ratcheting effects under cyclic translational movement