Performance of metakaolin based geopolymer concrete at elevated temperature

Due to the carbon dioxide emission arising from the production of cement, alternative concrete that is environmentally friendly such as metakaolin geopolymer concrete have been developed. However, the performance of metakaolin based geopolymer concrete (MKGC) when exposed to aggressive environment particularly elevated temperature has not been investigated. Therefore, this paper assessed the performance of MKGC exposed to elevated temperatures. MKGC cube specimens of grade 25 were produced using a mix ratio of 1:1.58:3.71.After preparing the specimens, they were placed in an electric oven at a temperature of 60oC for 24 hours. Thereafter, the specimens were stored in the laboratory at ambient temperature for 28 days. The specimens were then exposed to elevated temperatures of 200, 400, 600 and 800oC. After exposure to elevated temperatures, the MKGC specimens were subjected to compressive strength, water absorption and abrasion resistance tests. Results show that at 600 and 800oC, the MKGC lost a compressive strength of 59.69% and 71.71% respectively. Higher water absorption and lower abrasion resistance were also observed. Keywords: Cement, Compressive Strength, Metakaolin Concrete, Elevated Temperature

Mixing of the CP Even and the CP Odd Higgs Bosons and the EDM Constraints

The mixing among the CP even and the CP odd neutral Higgs bosons of MSSM by one loop induced effects in the presence of CP phases is investigated using three different mechanisms to satisfy the EDM constraints, i.e., a fine tuning of phases, a heavy sparticle spectrum, and the cancellation mechanism. It is shown that if a mixing effect among the CP even and the CP odd Higgs bosons is observed experimentally, then it is only the cancellation mechanism that can survive under the naturalness constraint.Comment: 14 pages, Latex and 4figures. A new paragraph is added and few more references. One figure is modified. To appear in Phys. Rev.

Hepatocurative Potentials of Camel (Camelus dromedarius) Urine and Milk on Carbon Tetrachloride Induced Hepatotoxicity in Albino Rats

Damage to the liver cells caused by diseases such as hepatitis and cirrhosis can lead to dysfunction of the liver, which can later result in hepatic or liver failure. The present study was carried out to investigate the hepatocurative effects of camel urine and milk on carbon tetrachloride (CCl4) induced hepatotoxicity in albino rats. Three different treatments (camel urine, camel milk and a 1:1 mixture of camel milk and urine) were administered to three different CCl4-induced hepatotoxic rats (Groups A,B and C) and also to three different subgroups (D,E and F) of normal rats for two weeks. A positive control (Group G) was neither induced nor treated while negative control group (H) received no treatment after CCl4-hepatotoxicity induction. Serum Alanine Amino Transferase (ALT), Aspartate Amino Transferase (AST) and Albumin (ALB) and histopathological findings all confirmed liver steatosis forty eight hours after CCl4 hepatotoxicity induction on randomly selected rats. A significant weight gain was recorded for rats that received camel milk and urine mixture in the CCl4 induced hepatotoxic group (P<0.05).A significant decrease in serum AST was observed in all test groups (P<0.05). Groups that received 1:1 urine and milk mixture showed a significant decrease at p<0.05 in serum ALT, AST and ALB than when treatments were administered singly. Camel urine resulted in periportal inflammation; camel milk resulted in vascular congestion while the 1:1 mixture of the two eliminated these side effects. In rats that received no treatment after hepatotoxicity induction, the condition of the liver deteriorated from liver steatosis to fibrosis and onset of cirrhosis. All these indicated that camel urine, camel milk and to a greater extent a mixture of the two, may have hepatocurative effects on CCl4 induced hepatotoxicity in albino rats. Keywords: Camel, Liver, Toxicity, Safety, Alternative medicine, hepatocurative

Status epilepticus in children: A five-year experience at Aga Khan University Hospital

Objective: Status epilepticus is an under diagnosed entity in Pakistan. It is a potentially reversible condition but has a high mortality, if it is not recognized and managed on time. The purpose of this study was to determine the clinical profile and the relationship of mortality of status epilepticus with its known risk factors.Methods: This was a retrospective study. Medical records of all the patients admitted in the last five years (1998-2002) with a diagnosis of status epilepticus (ICDcode 345.30, 345.31) were reviewed. Data was recorded on a Performa and analyzed by using the statistical programme SPSS, chi square and Fischer exact test.Results: The total number of patients were twenty-four. Sixteen patients were males (66.7%). Mean age was fifty-eight months and mean duration of hospital stay 5.5 days (range 2 to 22days). Eight patients were diagnosed to have epilepsy. Four (16.7%) had a previous history of status epilepticus. Three patients presented with status epilepticus for the first time without any previous history of seizures. Ten patients required midazolam infusion (41.7%) and out of these 3 (12.5%) were also given thiopentone infusion to control the seizures. Nine patients were shifted to the ICU for ventilation and control of seizures. Mortality in our study was 25%. Risk factors for mortality included age less than or equal to one year, abnormal MRI, type of the status epilepticus and the total duration of status epilepticus. No significant relationship was found with any of the known risk factors.Conclusion: Status epilepticus is a neurological emergency. A very high mortality was seen in our study. No risk factors were identified for this high mortality

Trapping of the Fruit-flies, Dacus spp. (Diptera: Tephritidae) with methyl eugenol in Orchards

Field trapping of fruit-flies Dacus spp. (Diptera: Tephritidae) using methyl eugenol over a five week period was conducted in a fruit farm at Gombah, Selaugor, The results showed that traps with slit holes caught the greatest number of fruit-flies. Over 85% of the flies caught were male, Dacus dorsalis, Hendel. When different formulations of methyl eugenol; malaathion 50EC + methyl eugenol, Carbaryl85S + methyl eugenol, Dipterex SP 95%) methyl eugenol and distilled water + methyl eugenol were tested at Serdang significant differences 'were only detected in the number of flies trapped in those traps with methyl eugenol -I- insecticides and those 'with methyl eugenol alone. The technique use were effective in controlling the fruit-flies for there was a reduction of 20% of damaged carambola fruits

CP-odd A^0 production at e^+e^- colliders in MSSM with CP violating phases

We study the production of a heavy CP-odd $A^0$ boson in association with a photon $e^+e^-\to A^0\gamma$ and a Z boson $e^+e^-\to A^0 Z$ as well as the single production of $A^0$ via $e^+e^- \to \nu_e\bar{\nu}_e A^0$ in the MSSM with CP violating phases. In the case of $e^+e^-\to A^0\gamma / A^0 Z$, we show that the squark contribution, which vanishes in the MSSM with real parameters, turns out to be sizeable in presence of CP violating phases in the soft SUSY parameters. For $e^+e^- \to \nu_e \bar{\nu}_e A^0$ in both the 2HDM and MSSM with real parameters, the cross section does not reach observable rates at a NLC. It is found that with a large CP violating phase for $A_t$, cross sections of the order 0.1 fb are attainable for all the processes $e^+e^-\to A^0\gamma$, $e^+e^-\to A^0 Z$ and $e^+e^- \to \nu_e \bar{\nu}_e A^0$.Comment: 12 pages, latex, 7 eps figures. One new figure, new discussion arroud it. Version to appear in Phys. Rev.

Haemolytic uraemic syndrome in childhood: An experience of 7 years at the Aga Khan University

We reviewed the case records of all children admitted to the Aga Khan University Hospital (AKUH) with a diagnosis of Haemolytic Uremic Syndrome (HUS) over a 7 year period (July, 1988-June, 1995). A total of 33 patients were admitted to the Pediatric ward at (AKUH) with a median age of 16 months (range 4 months-9 years). 97% cases identified were of the classic variety and no familial case was identified. The mean duration of illness was 27 days, 39% had an illness \u3e 28 days. Diarrhoea and prior antibiotic used was in 97% patients. Oliguria at admission was seen in 52.5% and seizures in 24% of cases. Thrombocytopenia, anemia and leucocytosis at admission was present in \u3e 72% of children. Hyponatremia was present in 42% while acidosis, hypocalcemia and hyperkalemia was seen in 30% of children. Despite optimal management and peritoneal dialysis in 14 (42%) patients, 8 (24%) died. No specific relationship was found between mortality and any clinical or laboratory feature at presentation. Our data highlights the importance of HUS in the Pediatric age group and the need for further studies to delineate risk factors for adverse outcome

Probing scalar-pseudoscalar mixing in the CP violating MSSM at high-energy e+e−e^+e^- colliders

We study the production processes $e^+e^-\to H^0_iZ$, $H^0_iH^0_j$ and $H^0_i\nu_e\overline \nu_e$ in the context of the CP violating MSSM. In a given channel we show that the cross-section for all i (=1,2,3) can be above 0.1 fb provided M_{H_{2,3}}\la 300 GeV. This should be detectable at a Next Linear Collider and would provide evidence for scalar-pseudoscalar mixing.Comment: 17 pages, RevTex, 4 ps figures, figure 4 changed, minor modifications to text, version to appear in PR

Top Squarks and Bottom Squarks in the MSSM with Complex Parameters

We present a phenomenological study of top squarks (~t_1,2) and bottom squarks (~b_1,2) in the Minimal Supersymmetric Standard Model (MSSM) with complex parameters A_t, A_b, \mu and M_1. In particular we focus on the CP phase dependence of the branching ratios of (~t_1,2) and (~b_1,2) decays. We give the formulae of the two-body decay widths and present numerical results. We find that the effect of the phases on the (~t_1,2) and (~b_1,2) decays can be quite significant in a large region of the MSSM parameter space. This could have important implications for (~t_1,2) and (~b_1,2) searches and the MSSM parameter determination in future collider experiments. We have also estimated the accuracy expected in the determination of the parameters of ~t_i and ~b_i by a global fit of the measured masses, decay branching ratios and production cross sections at e^+ e^- linear colliders with polarized beams. Analysing two scenarios, we find that the fundamental parameters apart from A_t and A_b can be determined with errors of 1% to 2%, assuming an integrated luminosity of 1 ab^-1 and a sufficiently large c.m.s. energy to produce also the heavier ~t_2 and ~b_2 states. The parameter A_t can be determined with an error of 2 - 3%, whereas the error on A_b is likely to be of the order of 50%.Comment: 31 pages, 8 figures, comments and references added, conclusions unchanged; version to appear in Phys. Rev.