Showing papers by "Jordan University of Science and Technology published in 1994"

Bifurcations, chaos, and crises in voltage collapse of a model power system

Abstract: Bifurcations occurring in power system models exhibiting voltage collapse have been the subject of several recent studies. Although such models have been shown to admit a variety of bifurcation phenomena, the view that voltage collapse is triggered by possibly the simplest of these, namely by the (static) saddle node bifurcation of the nominal equilibrium, has been the dominant one. The authors have recently shown that voltage collapse can occur "prior" to the saddle node bifurcation. In the present paper, a new dynamical mechanism for voltage collapse is determined: the boundary crisis of a strange attractor or synonymously a chaotic blue sky bifurcation. This determination is reached for an example power system model akin to one studied in several recent papers. More generally, blue sky bifurcations (not necessarily chaotic) are identified as important mechanisms deserving further consideration in the study of voltage collapse. >

Niosome Encapsulated of Vincristine Sulfate: Improved Anticancer Activity with Reduced Toxicity in Mice

Abstract: Nonionic surfactant vesicles (niosomes) are promising drug carriers for anticancer drugs. Niosome encapsulated vincristine sulfate prepared by transmembrane pH gradient drug uptake process (remote loading method) was evaluated for toxicity and antitumour activity after administration to tumour bearing mice. The toxicity of vincristine sulfate was reduced after niosome encapsulation and anticancer activity improved, which may be due to better delivery of vincristine at the tumour site.

Closed form solutions for bus and tree networks of processors load sharing a divisible job

Abstract: Optimal load allocation for load sharing a divisible job over processors interconnected in either a bus or a tree network is considered. The processors are either equipped with front-end processors or not so equipped. Closed form solutions for the minimum finish time and the optimal data allocation for each processor are obtained. The performance of large symmetric tree networks is examined by aggregating the component links and processors into a single equivalent processor. This allows an easy examination of large tree networks. In addition, it becomes possible to find a closed form solution for the optimal amount of data that is to be assigned to each processor in the tree network in order to achieve the minimum finish time. >

Intestinal colonization of symptomatic and asymptomatic schoolchildren with Blastocystis hominis.

Abstract: A study of single stool specimens was done to determine the prevalence of intestinal parasites among 1,000 primary school children. A questionnaire was completed by each child9s parents. Specimens were examined by using wet-mount preparation, formaline-ether concentration, and Sheather9s flotation technique. Trichrome and acid-fast stains were done. Blastocystis hominis was observed in 203 (20.3%) of the specimens examined, and 175 specimens contained this organism in the absence of other pathogenic parasites. Older children had fewer B. hominis infections (6 to 7 years old, 50% infection rate; 8 to 9 years, 27.5%; 10 to 12 years, 9.5%). The most common complaints reported by 75 children harboring the parasite were a mild recurrent diarrhea, abdominal pain, nausea, anorexia, and fatigue. Blastocystosis is quite common among schoolchildren. Contaminated drinking water is suspected to be the source of infection.

Hydatidosis in Jordan : an epidemiological study of 306 cases

Abstract: Of the 306 subjects studied, who had had hydatid cysts (Echinococcus granulosus) surgically excised in Jordan, 185 (60%) were female and 121 (40%) male. The liver was the most affected organ (57·8%), followed by the lung (26·4%). The kidneys, spleen, brain, soft tissues of neck, appendix and mesentery were less frequent sites. Multiple-organ infection was seen in 23 patients (7·5%). Over a third of the cases (35·8%) was aged <21 years and the commonest occupation was housewife, followed by school student. The epidemiology of hydatidosis transmission in Jordan is discussed.

Determinants and consequences of burnout: A cross‐cultural comparison of Canadian and Jordanian nurses

Abstract: We compared the determinants and consequences of burnout for Canadian (N = 586) and Jordanian (N = 263) registered nurses working in a hospital setting. LISREL 7 software was used to perform a path analysis testing hypothesized relationships between job satisfaction dimensions (supervision, hospital identification, kind of work, amount of work, physical work conditions, rewards, and career future) and burnout and intention to quit. For both Canadian and Jordanian nurses, kind of work, amount of work, and career future were important determinants of burnout. Career future and burnout (emotional exhaustion) were associated with intention to quit on the basis of the highly similar results across the two samples, we propose that a universal theoretical model of the determinants and consequences of burnout among nurses may be plausible.

Analysis of torsional torques in starting of large squirrel cage induction motors

Abstract: The paper presents a comprehensive study of the starting process of a large squirrel cage induction motor driving an inertia load through an elastic shaft. The analysis of the electromagnetic torque of the motor has revealed that there are variable frequency components which interact with the torsional mode of the mechanical system and produce hazardous shaft torque. This torque may exceed the maximum yield of the shaft or it may accumulate and result in a cyclic fatigue fracture. The nature of the problem is explained and the factors which aggravate its impact are discussed. Furthermore, it is shown that the torsional torque can be substantially reduced by the proper coordination of the switching operations. >

Knowledge-based assembly of simulation networks using construction designs, plans, and methods

Abstract: An object-oriented and interactive computer system is presented that integrates project- and process-level planning. This system, named CIPROS, realistically models construction processes by matching resource properties with design component properties and operation durations. It uses a modular representation to create discrete event simulation networks and to relate simulation output to the design and construction plan of the facility to be built. CIPROS users must identify and describe attributes of components to be constructed, based on the facility's design drawings and specifications, and they must develop a CPM plan. They must also select a construction method to perform each activity by retrieving the appropriate elemental simulation network from a library of networks that represent such methods. CIPROS then pieces the networks together based on sequential relationships from the plan and property values input from the drawing and specification data. The latter initialize the simulation network resources that make up the constructed facility. To complete the simulation network, users must specify the construction resources that are available to perform the work and which may be shared by activities. CIPROS comprises a fully-operational discrete event simulation engine that is called once a network is completed. Besides producing statistical reports that are instrumental in assessing the quality of the construction plan, CIPROS can also be used to check the degree of facility completion as the simulation progresses.

Hsp27 expression in neuroblastoma : correlation with disease stage

Abstract: BACKGROUND The 27-kd heat shock protein (Hsp27) is differentially expressed in some malignancies, including breast carcinoma, leukemia, and malignant fibrous histiocytoma. In breast carcinoma, a high-level expression of Hsp27 has been associated with shorter disease-free survival in patients with localized disease. PURPOSE We have observed variable levels of Hsp27 among neuroblastoma tumors. Our aim in this study was to investigate the relationship between Hsp27 expression and stage of the disease and N-myc gene copy number. METHODS We determined Hsp27 protein levels in 53 neuroblastoma tumors representing different stages of the disease and in 17 neuroblastoma cell lines by quantitative two-dimensional polyacrylamide gel electrophoresis (PAGE). We also performed statistical analysis of Hsp27 levels in relation to stage of the disease and to N-myc gene copy number. RESULTS Increased Hsp27 expression in neuroblastomas was associated with limited stage disease and inversely correlated with N-myc gene amplification, a feature known to predict poor clinical outcome. An inverse correlation was also observed between N-myc gene amplification and Hsp27 protein levels among the neuroblastoma cell lines analyzed. Immunohistochemical staining of sections of neuroblastomas showed that Hsp27 was most prominently expressed in the cytoplasm of large ganglionic tumor cells present in neuronally differentiated areas of the tumors. Induction of neuronal differentiation in SMS-KCNR neuroblastoma cells using retinoic acid resulted in an increase in Hsp27. CONCLUSION High level expression of Hsp27 in neuroblastoma is a feature of limited stage, differentiated tumors. IMPLICATION Hsp27 may play a part in the biology of neuroblastomas with a favorable outcome.

Analysis of Accident Reduction Potentials of Pavement Markings

Abstract: The major objective of this research was to apply a probabilistic procedure to evaluate the safety effectiveness of pavement marking of undivided rural roads. A 100 sites were randomly selected from the population of improved roads in the state of Indiana. In the analysis, accident reduction factors at the individual site level were estimated as a proportion based on the expected accident rates. To eliminate the effect of regression to the mean, a Bayesian approach was adopted to estimate expected accident rates in the before and after periods. Results of the analysis indicated that the beta distribution adequately fitted accident reduction factor frequencies. Also, accident reduction factors at individual site level were found to be positively correlated with accident rates in the before period. When pavement marking was considered at all sites irrespective of their accident experience, no statistically significant safety impact was observed. However, pavement marking at hazardous sites provided a significant level of accident reduction. Thus, it can be concluded that pavement marking does improve the safety of hazardous sites on rural undivided highways.

A double-blind comparison of sertraline and clomipramine in the treatment of major depressive disorder and associated anxiety in general practice.

Abstract: In this double-blind study in primary care patients, the efficacy and safety of sertraline, an antidepressant which is a selective inhibitor of serotonin re-uptake, was compared with clomipramine. Patients with DSM-III-defined major depression and with significant anxiety randomly received 50-150 mg of either sertraline (N=51) or clomipramine (N=55) once daily for 6 weeks. The mean final daily dose was 63.5 mg sertraline and 60.6 mg clomipramine. Seventy five percent of sertraline-treated and 79% of clomipramine-treated patients were maintained on the lowest dose of 50 mg once daily. The mean scores of all the rating scales (HAM-D, HAM-A, HAD, CGI) showed similar efficacy between the treatments in reducing the symptoms of depression and anxiety. Clomipramine was less well tolerated than sertraline with a greater overall incidence of side effects, or significantly greater incidence of anticholinergic side effects and significantly more patient withdrawals due to side effects; 18% in the clomipramine group compared with 4% in the sertraline group. The results indicate that sertraline is an effective agent to use in primary care patients with depression and associated symptoms of anxiety and is better tolerated than the tricyclic comparator clomipramine.

The effects of Ramadan fasting on certain biochemical parameters in normal subjects and in type II diabetic patients.

Abstract: Fasting levels of cholesterol, triglycerides, uric acid, fructosamine and glycosylated hemoglobin were measured in normal and in Type II diabetic subjects before the beginning and at the end of the Muslim month of fasting (Ramadan). In normal subjects, there was a significant increase (P<0.01) in triglycerides and uric acid levels as a result of Ramadan fasting. In diabetic patients, triglyceride levels decreased significantly (P<0.05), while uric acid levels showed a significant increase (P<0.01) as a result of the same type of fasting. There were no significant differences in cholesterol, fructosamine and glycosylated hemoglobin levels before and after fasting in either group. These finding suggest that although this type of fasting is effective in causing considerable changes in certain blood biochemical parameters in normal and diabetic subjects, it has no effect on the glycemic control of either normal or Type II diabetic subjects.

The effect of exposure to chlorhexidine gluconate in vitro and in vivo on in vitro adhesion of Candida albicans to buccal epithelial cells from diabetic and non-diabetic subjects.

Abstract: The effect of 0.2% chlorhexidine gluconate on in vitro adhesion of Candida albicans to buccal epithelial cells (BEC) was studied in 12 healthy subjects and 12 patients with diabetes mellitus. Exposure of BEC for one minute with 0.2% chlorhexidine gluconate in vitro, or by rinsing the mouth in vivo, resulted in a significant reduction in candidal adhesion to BEC in both diabetic and non-diabetic subjects and between both groups. In addition to the known fungicidal effect of chlorhexidine, it also reduces Candida albicans adhesion to oral mucosal cells, a factor of importance in the establishment of candidal infection.

Damping of parametrically excited single-degree-of-freedom systems

Abstract: A single-degree-of-freedom parametrically excited system coupled with a Lanchester damper, a mass-dashpot device, is studied. The two equations governing the total system are solved using the method of multiple scales for the case of principal parametric resonance. Steady-state solutions are obtained and the effect of the various system parameters examined. The stability analysis for the steady-state solution is also carried out. Results show that this damper can limit the maximum response of the main system and delay the onset of the force threshold necessary to trigger a non-trivial stable response.

Prevalence of Cryptosporidium species in elementary school children.

Abstract: The project described here was conducted to study the prevalence of various parasites in elementary school children in northern Jordan. A single stool specimen was collected from each of 1,000 students in the 6- to 14-year-old age group. A questionnaire covering demographic information, health status, and other relevant information was filled out by one of the parents of each student. Fresh stool specimens were processed by using wet mount preparations, formalin-ether, and Sheather's sugar flotation techniques. Permanently stained slides were prepared by acid-fast, Giemsa, and trichrome staining. Cryptosporidium species was found in 40 specimens (4%); however, only 15 specimens had Cryptosporidium species alone, and these 15 specimens were from symptomatic children with diarrheic stools. The symptoms reported most often were abdominal pain, cramps, malaise, nausea, and headache. The number of cases of infection was higher in villages, where contact with animals was evident and where contaminated drinking water could have been a major source of the infections.

Prevalence of giardiasis among primary school children

Abstract: Giardia is one of the most frequently isolated intestinal protozoa and is found worldwide in both developing and more developed countries. Clinical aspects of human infection with Giardia range from the asymptomatic carrier state to severe malabsorption. Host-related factors parasite-related factors and host-parasite interactions affect the outcome of infection with social environmental and climactic factors influencing the prevalence of Giardia infection. The author collected a single stool specimen from each of 1100 children aged 6-14 years of both sexes from urban and rural schools to investigate the prevalence of intestinal parasites among primary school children in northern Jordan. Questionnaires on relevant information were completed for each child. Giardia lamblia was observed in 396 (36%) of the 1100 stool specimens analyzed. 41.3% were infected in the 6-9 year old group 30% in the 9-12 year old group and 27.7% in the over 12 year old group. Several in the youngest group had diarrhea and reported variable symptoms. Rates were higher in children from rural areas from children in families of relatively low income and among males. Contaminated drinking water is suspected to be the major source of infection. The author discusses the importance of the asymptomatic cases and the epidemiological factors contributing to transmission in these areas.

Cryptosporidium. A cause of gastroenteritis in preschool children in Jordan.

Abstract: In this case-control study, we investigated the role of Cryptosporidium in gastroenteritis in children < 6 years old. Six hundred fresh stool specimens were examined for various pathogenic parasites, bacteria, and rotaviruses. Wet-mount preparations, formaline-ether concentrations, and Sheather's floatation techniques were used to recover the parasite oocysts. Permanent stained slides using acid-fast stain and trichrome stains were prepared. Of 300 children with gastroenteritis symptoms, 20 (6.7%) had Cryptosporidium oocysts; seven of the 20 had concomitant infections so they were excluded from the counts. This infection rate is significantly different (Z = 2; p < 0.05) from that found in the control group (1.7%) of children who reported no symptoms. The most frequent symptoms reported beside diarrhea were abdominal pain, cramps, anorexia, nausea, vomiting, and fatigue. Contaminated drinking water is suspected to be the source of infection; other possible factors are discussed.

A hybrid finite element-analytical solutions for inhomogeneously filled shielding enclosures

Abstract: The analytical solutions of an arbitrary-large rectangular cavity with an aperture, are coupled to the edge-based finite-element method solution of the remaining inhomogeneous part of the problem. This hybrid method (finite elements-analytical solutions) has the advantages of producing a sparse matrix and substantially reducing the number of unknowns. The computer storage and processing time requirements are also reduced. The numerical results of this hybrid method are in agreement with the pure edge-based finite-element method solutions. Measurements were also performed and the results compare favorably with the hybrid solution. The applications considered involve one of the problems that concern the EMC community, namely, the computation of the crosstalk between signal tracks on dielectric boards inside shielded enclosures. >

Chronic recurrent multifocal osteomyelitis associated with tumoral calcinosis.

Abstract: VOL. 76-B, No. 2, MARCH 1994 is often a family history of similar masses. Radiographicatty, the lesion appears as a welt-demarcated mass of lobutated, round or oval catcifications in the periarticular soft tissues. No bony abnormalities are seen and the joint space is not involved. Hyperphosphataemia is the only biochemical abnormality which has been detected (Reddy and Rao 1964; Lafferty, Reynolds and Pearson 1965; Baldursson et at 1969). Treatments have included excision, radiotherapy (Inclan 1943), special diets and various oral and parenteral drugs including corticosteroids and ACTH (Scott and DeLilly 1954). None has proved curative but there have been good results from early excision of initial and recurrent lesions. The clinical and histological features are not always so typical. The histological appearance of our case represents a variant of tumour calcinosis; the calcification is relatively mild and much of the tumour consists of macrophages and an osteoclast-tike or giant-cell reaction to the psammoma bodies which are composed of amorphous material. Confirmation of the diagnosis may be difficult because of the wide range of radiological and histological features. The radiographic appearance may arouse concern that there has been malignant change within a benign lesion, but careful histological analysis can usually reassure the patient and the surgeon that the lesion is innocent.

Systematics and distribution of scorpions (Arachnida, Scorpionida) in Jordan

Abstract: The distribution and systematics of the scorpion fauna of Jordan are presented. Thirteen species of scorpions are included, as well as a taxonomic key and the current distribution for each species. An attempt to define the zoogeography of the Jordanian scorpions is discussed.