Modeling the frequency-dependent hydrogen-assisted fatigue crack growth in engineering alloys

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Modeling the frequency-dependent hydrogen-assisted fatigue crack growth in engineering alloys

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Long-term behaviour of aramid fibre

PhD ThesisAn investigation of the creep rupture of Kevlar@ 29, Twaron@ 1000, and Technora T2000 aramid fibre yams was carried out in the temperature range 25-120T in air and three other environments (Saudi/Iranian crude oil, pure water, and low pH water) at 65T with the objective of characterising the long term failure behaviour of these fibres and determine if they can be used to replace the stress rupture test conducted on RTP for qualification purposes. The standard loglo-loglo ISO 9080 extrapolation procedure, the modified lin-logio ISO 9080 extrapolation procedure and the time temperature superposition method were used to model and interpret the results. When tested in air, the different yams showed similar but not identical regression parameters. The results of the standard logio-logio ISO 9080 and the modified lin-logio methods correlated well. The standard logio-logio form, however, gave slightly higher values for the 20 year mean stress and LPL. Its use is recommended because it is consistent with the model assumed in the regression of RTP. There was no evidence of any 'knee' in the relationships after long periods or at high temperatures. This suggests that there is no change in failure mechanism, and lends confidence to both the long term use of aramid fibre in air and the recommended qualification procedures. RTP regression curve constants and those of tested aramid fibre were similar indicating the validity of aramid fibre stress rupture tests as a replacement for RTP tests. Crude oil immersion produced a small but significant reduction in behaviour. At 650C a suitable crude oil reduction factor applied to the long ten-n LPL would be 0.9. Pure water produces a marked reduction in strength after short periods, at 65C. Finally, water of low pH resulted in a large reduction in performance and considerable scatter with one fibre type. With the other, the effect appeared to be similar to that of pure water. Based on the understanding of the failure mechanism and the creep process in aramid fibres, a creep strain model is proposed for estimating the strain to failure based on the material's properties.Saudi Aramc

KETERLIBATAN ORGAN PADA PASIEN LEPTOSPIROSIS DI RSUP DR KARIADI SEMARANG (Perbedaan Keterlibatan Organ pada Pasien Leptospirosis Ikterik dan Leptospirosis Anikterik)

Background: Leptospirosis is a zoonotic disease that is widespread in the world. The incidence of leptospirosis in Indonesia, especially in Semarang is still quite high and leptospirosis can cause organ involvement that can increase patient morbidity. Purpose: Measuring organ involvement in patients with leptospirosis in the Hospital Dr. Kariadi and analyze differences in organ involvement in icteric leptospirosis and anicteric leptospirosis patients. Methods: This study is a descriptive analytic. Data were taken from the case record form of clinical research data leptospirosis Hospital Dr. Kariadi. Subjects were all patients with confirmed leptospirosis, with a total of 84 patients. Diagnosis is made by MAT. Differences in hepatic involvement, renal, pulmonary and cardiac were analyzed by Fisher's Exact test, while the difference in hematologic organ involvement were analyzed by Kolmogorov Smirnof 2 samples. Results: In patients with icteric leptospirosis, organ involvement is the hepatic appears most 100%, followed by renal 98.3%, hematologic 74.1%, cardiac 32.8%, and pulmonary 32.8%. In anicteric leptospirosis patients, organ involvement is the most widely renal 76.9%, followed by hepatic 73.1%, hematologic 53.8%, pulmonary 23.1% and cardiac 23.1%. There is a difference between renal and hepatic involvement in patients with icteric and anicteric leptospirosis (p <0.05). There is no difference between pulmonary, cardiac, and hematologic involvement in patients with icteric and anicteric leptospirosis (p> 0.05). Conclusion: There is a difference between kidney and liver involvement in icteric leptospirosis and anikteric leptospirosis patiens. There is no difference between pulmonary, cardiac and hematologic involvement in icteric leptospirosis and anikteric leptospirosis patients. Keywords: Leptospirosis, organ involvemen

Aluminum-induced testosterone decrease results in physiological and behavioral changes in male mice

Recently, there has been much controversy on the role of testosterone on social and aggression behaviors. This work aimed to determine the effect of testosterone decrease, induced by aluminum exposure on the level of aggression. Male Swiss-Webster strain mice were classified into three groups. The first (control group) received distilled water, while the second and third groups were administrated 300 and 600 mg/kg aluminum chloride, respectively, by oral route for 20 days. Thereafter, they were subjected to “standard opponent” test. A significant decrease in testosterone levels in the treated groups was obtained at both the low and high doses of aluminum. Expectedly, significant decreases were observed in the social contacts, threat, attack and number of fights of both treated groups in a dose dependant manner. All blood parameters revealed a dose dependent significant decrease as well. A significant decrease in both serotonin and dopamine levels was simultaneously obtained with the decrease of testosterone level especially at the high dose of aluminum. In contrast, at the high dose, acetylcholine recorded significantly high value. In conclusion, aluminum-induced testosterone decrease resulted in a significant decline in aggression, several blood parameters and levels of neurotransmitters.Keywords: Aluminum, Swiss-Webster mice, standard opponent test, social behavior, testosteron

Polymorphisms of TLR4 Asp299Gly and TNF-α -308G/A in Leptospirosis

Background : TLR4 Asp299Gly and TNF-α -308G/A polymorphisms have been shown to be associated with increased susceptibility and severity of infection. TLR4 Asp299Gly polymorphism could affect the host's ability to respond to leptospira sp. TNF-α -308G/A polymorphism, is associated with the high producer of TNF-α.Methods : Total of 36 leptospirosis patients (IgM anti leptospira and MAT positive) and healthy individual with the equal number were included. The polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using site spesific restriction enzyme.Results : Distribution of homozygous wild-type TLR4 Asp299Gly polymorphism was higher in both of groups ( 94.5:97.2%.) and homozygous mutant allele was absent. There was not significantly difference of TLR4 Asp299Gly in leptospirosis patients and healthy group ( ρ=1.00; OR 0.5; 95%CI, 0.04-5.6) and between mild and severe leptospirosis (ρ=0.54; OR 1.54 ; 95% CI, 1.20-1.98). The presence of homozygous wild-type TNF-α -308G/A polymorphism was higher between leptospirosis patients and healthy group (100:94.5%) andhomozygous mutant allele was not found in both of the groups. No significantly different of TNF-α -308G>A polymorphism between leptospirosis patient and healthy group (ρ=0.49).Conclusions : In this study, the polymorphisms of TLR4 Asp299Gly and TNF-α -308G/A were not associated with the susceptibility and severity of leptospirosis

The Effectiveness of Mangosteen Peels Extract Against the Total of T Lymphocytes in HIV Patients

Introduction: The Province of West Java is one of the highest HIV sufferers in Indonesia that has increased accumulatively in 2013 to 2014. This condition was proven that in 2014 West Java ranked 4th among the provinces with the highest HIV sufferers in Indonesia. HIV has main target to infect a cell that contains of receptor, CD4. CD4 examination routinely is very important to decide HIV replication process. Meanwhile, CD4 test in the laboratory is quite expensive and not always available in every health facilities. Mangosteen peels extract contains of xanthones as an antioxidant, which is needed for body as a prooxidant that can inhibit the replication of HIV and the activity was seen from the total number of lymphocyte. Method: The human experimental research has been done by Randomized Control Group Pretest-Post Test Design. There were 20 patients sample for each group. In group 1, HIV patients with ARV therapy were given mangosteen peels extract and in group 2, they were given placebo capsule. Wilcoxon Smith test and Mann Whitney U test were used to determine the difference between group 1 and group 2. Result: There is no significant difference between lymphocytes (p: 0.102) to HIV patients with ARV in each group examination. Discussion: The ineffectiveness is caused by the phagocytocity and cytoxity of TNF through the increasing of free radicals in HIV patients

The Effects of Quinacrine, Proglumide, and Pentoxifylline on Seizure Activity, Cognitive Deficit, and Oxidative Stress in Rat Lithium-Pilocarpine Model of Status Epilepticus

The present data indicate that status epilepticus (SE) induced in adult rats is associated with cognitive dysfunctions and cerebral oxidative stress (OS). This has been demonstrated using lithium-pilocarpine (Li-Pc) model of SE. OS occurring in hippocampus and striatum of mature brain following SE is apparently due to both the increased free radicals production and the limited antioxidant defense. Pronounced alterations were noticed in the enzymatic, glutathione-S transferase (GST), catalase (CAT), and superoxide dismutase (SOD), as well as in the nonenzymatic; thiobarbituric acid (TBARS) and reduced glutathione (GST), indices of OS in the hippocampus and striatum of SE induced animals. Quinacrine (Qcn), proglumide (Pgm), and pentoxifylline (Ptx) administered to animals before inducing SE, were significantly effective in ameliorating the seizure activities, cognitive dysfunctions, and cerebral OS. The findings suggest that all the drugs were effective in the order of Ptx < Pgm < Qcn indicating that these drugs are potentially antiepileptic as well as antioxidant; however, further studies are needed to establish this fact. It can be assumed that these antiepileptic substances with antioxidant properties combined with conventional therapies might provide a beneficial effect in treatment of epilepsy through ameliorating the cerebral OS

PROFIL KLINIK DAN LABORATORIUM PASIEN COMMUNITY ACQUIRED PNEUMONIA SEMBUH DAN MENINGGAL DI RSUP DOKTER KARIADI

Background: Community acquired pneumonia (CAP) is an infectious disease of the lungs that frequently occurs and causes of death. Further research is needed to understand the clinical and laboratory profiles of CAP patients and early detection on patients with high risk of death. Objective: To compare the clinical and laboratory profile of CAP patients (when patient entered the hospital) of cured and died (30 days mortality rate) at Dr. Kariadi Hospital. Methods: This was a retrospective comparative with cross sectional study. It used secondary data from case record form CAPSIN at Dr. Kariadi Hospital Semarang on 2007 until 2009. The subjects were 133 CAP patients. Statistical analysis used logistic regression test. Results: The most frequent clinical profiles that appeared were cough (94%), dyspnea (88.7%), fever (88%), and sputum (68.4%). Leukocytes (69.9%), hemoglobin (68.4%), urea (63.9%), and hematocrit (63.9%) were the most frequently abnormal laboratory results. Decrease of consciousness (p = 0.002) and creatinine levels (p = 0.016) had a significant relationship to the outcome of patients with CAP with logistic regression test Conclusions: Decrease of consciousness and abnormality creatinine levels contributes to the CAP patient outcomes. A decrease in consciousness and abnormality of creatinine levels in patients with CAP increases the risk of death by 85.7%. Key words: Community acquired pneumonia, clinical profile, laboratory profil