In this study, a specifically designed direct-acting continuously variable valve timing mechanism was used to determine speed optimised valve timings for best volumetric efficiency of an engine. This ...mechanism basically consists of a piezo stack and a hydraulic magnifier integrated into it. To avoid effects of excessive vibrations on the piezo-stack, the engine was operated in a non-combustion mode. An electric motor was used to power the engine. Some system limitations of the hydraulic magnifier and the piezo-stack were the main challenges to a non-stop operation. A valve lift of approximately 4 mm, obtained with maximum applicable voltage of 600V to the piezo-stack, was referred to for comparison instead of the 7.6 mm original value. Tests were conducted for 30 inlet valve timing combinations at four different engine speeds from 1500 to 3000 rpm with 500 rpm increments. Timing pairs for the best VE were determined. They yielded 11.5% to 19.4% better volumetric efficiencies at 4mm lift than those obtained with the original valve timing of the cold engine. We also predicted 5-11.5% overall efficiency improvement, depending on engine type and operating conditions. Despite some practical challenges, better VE values have been obtained for a specific engine at varied speeds.
Summary
The protective effect of quercetin on cisplatin‐induced renal and testicular tissue damage was investigated using biochemical, histopathological and histological approaches. A total of 40 ...male rats were divided into 5 groups as follows: control; cisplatin alone; quercetin alone; cisplatin + quercetin; and quercetin + cisplatin. Cisplatin was administered to rats at a single dose of 7 mg kg−1 intraperitoneal. Quercetin was administered by gavage daily for 10 days at dosage 50 mg kg−1. At the end of the study serum, total antioxidant capacity (TAC) levels and total oxidant status (TOS) were determined. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and xanthine oxidase (XO) were studied separately in serum, renal tissue and testicular tissue. Renal and testicular morphological alterations were assessed, histopathologically. Epididymal sperm concentration, motility and morphology were investigated. Testicular and renal TAC and TOS values did not alter significantly. Renal CAT levels were increased by cisplatin and cisplatin plus quercetin groups that is reversed by administration of quercetin before cisplatin. MDA, CAT, SOD ve XO levels of testicular tissue did not differ significantly. Cisplatin and cisplatin plus quercetin groups had decreased sperm motility ratio and increased abnormal spermatozoa. Quercetin partially reverses some of the cisplatin‐related pathological effects on kidney and testis.
The present study investigated the optimization of arsenic adsorption onto natural clinoptilolite (NC-Na). Response surface methodology in combination with Box–Behnken design was used to optimize the ...parameters of the adsorption process. Solution pH, temperature, and initial arsenic concentration were chosen as the main process variables, and the amount of arsenic adsorbed was selected as the investigated response. The analysis of variance results of the response surface model for arsenate (As(V)) adsorption on NC-Na showed that the effects and the interactions of pH and temperature were highly significant according to the p values (p < 0.05). The optimum conditions were found to be the solution pH of 5.0, temperature of 45 °C, and initial concentration of 7.8 mg L⁻¹. The response surfaces derived from the models revealed that solution pH and temperature showed the greatest effect on the As(V) adsorption capacity of natural clinoptilolite.
Objective Recent studies have shown that a Type D personality is associated with an increased risk of cardiac mortality. This study aimed to examine impact of a Type D personality on clinical and ...psychometric properties of patients with a first myocardial infarction (MI) in a Turkish sample. Method The study included 131 patients who were admitted to the coronary care unit of a hospital with a first MI. All the patients underwent a psychiatric assessment within 2–6 months post-MI. Psychiatric interviews were conducted with the Structured Clinical Interview for DSM-IV (SCID-I). Results The first study group (Type D personality) included 50 patients, and the second study group (non-Type D personality) included 81 patients. There was a 38.2% prevalence of the Type D personality in the patients with a first MI. Those with this type of personality had a significantly higher frequency of hypertension and stressful life events. The Type D patients also had more psychiatric disorders, depressive disorders, and anxiety disorders than the non-Type D patients. Conclusions Our findings suggest that Type D personality traits may increase the risk of hypertension and the risk of psychiatric morbidity in patients with a first MI. Considering that a Type D personality is a stable trait; we suggest that this type of personality is a facilitator of clinical depression and anxiety disorders. These findings emphasize the importance of screening for a Type D personality as a cardiovascular risk marker and a psychiatric risk marker in MI patients.
Background Relation of serum serum rheumatoid factor (RF) levels with extent, severity, and complexity of coronary artery disease has not been adequately studied. ...we assessed the relationship ...between the severity of coronary artery disease assessed by SYNTAX score and serum RF levels in patients with stable coronary artery disease (SCAD).
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