On the Dynamics of a Three Stage Single Acting Reciprocating Compressor

The growing demand in the market for highly efficient, more reliable and less expensive compressors have activated the manufacturers to develop state-of-the-art analytical tools to predict, evaluate and optimize the existing as well as creating the new designs. Development of a mathematical tool for predicting the dynamic behavior saves considerable time and reduces the unnecessary number of prototypes as well as the development costs. In the present study, a non-linear dynamic model of a three stage single acting reciprocating compressor is developed to predict the entire motion of the compressor. The analytical model prepared for simulation of the motion is initially tested in a limited experiments for validation and an experimental setup is prepared. Pressure transducers are carefully mounted to record the pressure variation within the cylinder. Using this data the steady state PV-diagram is constructed and the pressure variation within the cylinder is obtained as function of the crank angle. Further modifications are being made in the setup to identify the angular position of the crank shaft and to record the angular speed of the crank shaft as a function of time. With these modifications the analytical model results are compared with the experimental findings and good agreement was observed. Then, a number of parametric studies are performed and the results are presented in the study

Effect of rosuvastatin on arginase enzyme activity and polyamine production in experimental breast cancer

Background: Breast cancer is the most common malignant tumour of women around the world. As a key enzyme of the urea cycle, arginase leads to the formation of urea and ornithine from L-arginine. In the patients with several different cancers, arginase has been found to be higher and reported to be a useful biological marker. Aims: The aim of this study was to investigate the effect of rosuvastatin on serum and cancer tissue arginase enzyme activity, and ornithine and polyamine (putrescine, spermidine, spermine) levels. Study Design: Animal experiment. Methods: In this study, 50 male Balb/c mice were used. Erchlich acid tumour cells were injected into the subcutaneous part of their left foot. The mice were divided into five groups: healthy control group, healthy treatment, tumour control, treatment 1 and treatment 2. Then, 1 mg/kg and 20 mg/kg doses of rosuvastatin were given intraperitoneally. Serum and tissue arginase enzyme activities and tissue ornithine levels were determined spectrophotometrically. HPLC measurement of polyamines were applied. Results: Increased serum arginase activity and polyamine levels were significantly decreased with rosuv- astatin treatment. In the tumour tissue, arginase activity and ornithine levels were significantly decreased in treatment groups compared to the tumour group. Tissue polyamine levels also decreased with rosuvastatin treatment. Conclusion: We suggest that rosuvastatin may have some protective effects on breast cancer development as it inhibits arginase enzyme activity and ornithine levels, precursors of polyamines, and also polyamine levels. This protective effect may be through the induction of nitric oxide (NO) production via nitric oxide synthase (NOS). As a promising anticancer agent, the net effects of rosuvastatin in this mechanism should be supported with more advanced studies and new parameters

Insecticidal Effect of Usnea longissima (Parmeliaceae) Extract against Sitophilus granarius (Coleoptera: Curculionidae)

Two secondary metabolites (diffractaic acid & usnic acid) and extract of a lichen species, Usnea longissima Ach. were tested against adults of Sitophilus granarius (L.) on Petri dishes. After exposure, mortality of the adults was determined at 24th, 48th and 96th h. The results showed that secondary metabolites and extract of U. longissima have an insecticidal effect on adults of Sitophilus granarius (L.) in comparison with controls. The insecticidal effect was influenced by the concentrations of the extracts and the exposure time. Higher concentrations and longer exposure time resulted in maximum toxicity on S. granarius. Treatment with extract and lichen compounds of U. longissima pointed out equal mortality against adults of S. granarius. The mortality rates after 96 h of treatment with the maximum concentration (10 mg mL-1) of U. longissima extract, diffractaic acid and usnic acid were determined as 98.98, 91.91 and 94.94% for S. granarius, respectively. However, there was no mortality in the controls. The mortality rates after 96 h of treatment with the 10 mg mL-1 in concentrations of the extract of U. longissima were established and the highest mortality rate was found against S. granarius with 98.98%

Caffeine Increases Apolipoprotein A-1 and Paraoxonase-1 but not Paraoxonase-3 Protein Levels in Human-Derived Liver (HepG2) Cells

Background: Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 are antioxidant and anti-atherosclerotic structural high-density lipoprotein proteins that are mainly synthesized by the liver. No study has ever been performed to specifically examine the effects of caffeine on paraoxonase enzymes and on liver apolipoprotein A-1 protein levels. Aims: To investigate the dose-dependent effects of caffeine on liver apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 protein levels. Study Design: In vitro experimental study. Methods: HepG2 cells were incubated with 0 (control), 10, 50 and 200 ?M of caffeine for 24 hours. Cell viability was evaluated by 3-(4,5-Dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide assay. ApolipoproteinA-1, paraoxonase-1 and paraoxonase-3 protein levels were measured by western blotting. Results: We observed a significant increase on apolipoprotein A-1 and paraoxonase-1 protein levels in the cells incubated with 50 µM of caffeine and a significant increase on paraoxonase-1 protein level in the cells incubated with 200 µM of caffeine. Conclusion: Our study showed that caffeine does not change paraoxonase-3 protein level, but the higher doses used in our study do cause an increase in both apolipoprotein A-1 and paraoxonase-1 protein levels in liver cell

Protective effects of pomiferin isolated from Maclura pomifera on ischemia-reperfusion injury of rat ovary: biochemical and histopathologic evaluation

Background: The aim of this study was to investigate the antioxidant and anti-inflammatory properties of pomiferin, a prenylated flavonoid was purified from Maclura pomifera by thin layer chromatography method, on oxidative stress, sterile inflamation and ovarian tissue damage caused by ischemia-reperfusion model. Methods: Thirty female Wistar albino rats were divided into five groups. In the group CN only laparotomy operation was performed. In group CNPomiferin, rats received 200 mg/kg pomiferin. In group IRVehicle, reperfusion for 3 h performed after an ischemic period of 3 hours. In groups IRPomiferin100 and IRPomiferin200 rats received 100 mg/kg and 200 mg/kg doses of pomiferin, by oral gavage 1 houes before reperfusion. After the experiments, tissue level of malondialdehyde (MDA) and activities of myeloperoxidase (MPO), catalase (CAT), superoxide dismutase (SOD) were determined, and histopathological changes were examined in all rat ovarian tissue. Results: It was determined that irreversible cell damage such as apoptotic and necrotic deaths and reversible cell damage occurred in follicular, endothelial and stromal cells due to oxidative stress in the group IRVehicle. In this group, it was determined that the LPO level exceeded the cellular antioxidant capacity (SOD and CAT enzyme activities) and the PMNL infiltration and activity (MPO), an indicator of sterile inflammation, increased. It was determined that oxidative stress sterile inflammation and irreversible cell damage decreased in a dose-dependent manner with pomiferin treatment. Conclusions: Pomipherin treatment strongly protects ovarian follicles and vascular structures against ischemia-reperfusion injury, thus it may prevent the reduction of ovarian follicle reserve, which is an indicator of female fertility

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INVESTIGATION OF REINFORCEMENT RATE AFFECTING MECHANICAL PROPERTIES AND MACHINABILITY IN Al-SiCp MMCs

In this study, the effects of various rate of reinforcement materials (SiCp) addition to Al Si7 Mg2 metal matrix composite on mechanical properties and machinability were investigated. It was noticed that the mechanical properties increased with increasing added reinforcement materials rate in 5, 10 and 15 % SiCp reinforced metal matrix composite. The investigation of tool wear and surface roughness was carried out by using different cutting speeds (50, 100 and 150 m/min) and feed rate (0.1, 0.2 and 0.3 mm/rev) at constant depth of cut (1.5 mm) and reinforcement rates. It was observed that, tool wear and surface roughness increased when reinforcement material rate raised at using the same cutting speed and feed values. The tool life was a maximum when 15 % SiCp reinforced metal matrix composite was machined at 150 m/min of cutting speed. The highest surface roughness was also noticed at 15 % SiCp reinforced metal matrix composite machined at 50 m/min of cutting speed and 0.3 mm/rev of feed

Intense fluoro‑2‑deoxyglucose uptake in high‑grade prostatic adenocarcinoma with negligible prostate‑specific membrane antigen expression

While 68Gallium prostate-specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA) has demonstrated increasing utility in the evaluation of prostatic carcinoma, it is essential to be aware of false-negative findings. Further subtype analyses of prostate cancer will be helpful in the understanding of the underlying reasons. We herein present a high-grade prostate adenocarcinoma, with metastatic lesions showing high 18F-labeled fluoro-2-deoxyglucose uptake instead of 68Ga-PSMA

A case with intravascular large B cell lymphoma who was presented with fever of unknown origin, edema and generalized telangiectesia

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