58 research outputs found
Hypermethylation of tumor suppressor genes in gastric cancer: associations with demographic and clinicopathological characteristics
Background: Gastric cancer (GC) is one of the most common cancers worldwide. Despite the declining prevalence in Western countries, it is still a major health problem in Turkey and Asian countries. In the current study, we investigated the hypermethylation status of 25 TSGs in GC. Furthermore, the association between hypermethylation status of these TSGs and some demographic and clinicopathological characteristics were investigated.Methods: Formalin-fixed paraffin-embedded tissue samples obtained from 27 patients with GC and genomic DNA isolated from these tissues. To compare the methylation status of 25 TSGs, methylation-specific multiplex ligation-dependent probe amplification (MS–MLPA) technique was used. Results were evaluated in terms of age, gender, positive lymph node status, lymphovascular invasion, perineural invasion, mortality and five-years of survival, retrospectively.Results: Tumor suppressor gene hypermethylation was detected 16 (59.3%) of 27 GC tissues. Patients with hypermethylation-detected and patients with no hypermethylation-detected in their TSGs were classified as group 1 and group 2, respectively. The mean age of group 1 was 66.38±7.43 and the mean age of group 2 was found as 58.18±11.12 (p= 0.03). Hypermethylation was detected in 12 of 25 TSGs in patients with GC. Hypermethylation was detected as 51.8% for WT1, 40.7% for ESR1, 18.5% for CDH13, 14.8% for MSH6 and CD44, 7.4% for TP73 and PAX5 genes in the tumor tissues of patients with GC. Mean positive lymph node number was 8.81±5.38 in group 1 and 4.81±3.21 in group 2 (p= 0.037). Lymphovascular invasion, perineural invasion, mortality and five-years of mean survival were not statistically different between group 1 and group 2 (p>0.05 for all comparisons).Conclusions: Hypermethylation frequency of certain tumor suppressor genes may increase with advancing age and with positive lymph nodes in gastric cancer patients.
Do the Changes in the Serum Levels of IL-2, IL-4, TNFα, and IL-6 Reflect the Inflammatory Activity in the Patients with Post-ERCP Pancreatitis?
Background. Acute pancreatitis is the major complication of endoscopic retrograde cholangiopancreatography (ERCP) procedure and there are some reports showing cytokine changes in ERCP-induced pancreatits. Goals. To investigate the association between early changes (within 24 hours) in the serum interleukin (IL)-2, IL-4, tumor necrosis factor (TNF)α, and IL-6 levels and the development of post-ERCP pancreatitis. Study. Forty five consecutive patients who underwent therapeutic ERCP and 10 patients with acute pancreatitis without ERCP were enrolled to the study. Serum concentrations of IL-2, IL-4, TNFα, and IL-6 were determined immediately before, 12 hours and 24 hours after ERCP. Results. Seven of the 45 patients (15.5%) developed post-ERCP pancreatitis. The levels of IL-4 at 24 hours after ERCP were significantly lower in the patients with post-ERCP pancreatitis than in those without pancreatitis, while TNFα levels at 12 hours after ERCP were higher in the complicated group than those of the uncomplicated group. The ratios of TNFα/IL-4 at 12 and 24 hours after ERCP were found significantly higher in the patients with post-ERCP pancreatitis than in those without pancreatitis. IL-6 in the complicated patients was found significantly increased at 24 hours after ERCP. Conclusions. The enhancement of serum TNFα and IL-6 levels in the patients with ERCP-induced pancreatitis reflects the inflammatory activity. Additionally, these cytokines together with IL-4 can be used in clinical laboratory monitoring of ERCP
Primjena i kompozicija individualiziranih zaštitnih elemenata linijske grafike u projektiranju novčanica
Proces stvaranja novčanica je dugotrajan i složen, što rezultira kompleksnim rješenjima koja predstavljaju pravo remek djelo grafike. Novčanice su prožete brojnim detaljima i prenose različite informacije koje se analiziraju u teorijskom dijelu rada.
Prvotno se postavljaju kriteriji po kojima se izrađuje detaljna analiza velikog broja zaštitnih i konceptualnih elemenata na primjerima novčanica. Time je prikazan okvirni povijesni pregled razvoja novčanica i utjecaji kojima je bio izložen. Analizira se međuovisnost dizajna o sigurnosnim značajkama, te se ispituje razina informiranosti javnosti o zaštitama na novčanicama. Zaključuje se koje metode zaštite su najučinkovitije, te kako šira javnost najčešće provjerava autentičnost novčanica.
U eksperimentalnom dijelu rada se na temelju donesenih zaključaka iz teorijskog dijela izrađuje prototip novčanice koja je u najvećoj mjeri prožeta individualiziranim PostScript programskim rješenjima elemenata linijske grafike (rozete, mikrotekst, zaštitne linije, brojevi apoena), a od ostalih zaštita modeliran je individualizirani raster transformacijom matematičkog izraza u PostScript programski kod. Sve ostale zaštite tipične za novčanice simulirane su alatima za rastersku i vektorsku grafiku. U radu se ispituje utjecaj kompozicije zaštitnih elemenata na prepoznavanje autentičnosti novčanica, te efikasnost samih individualiziranih programskih rješenja
Characterization and kinetics of light crude oil combustion in the presence of metallic salts
In this research, a reaction cell, thermogravimetry (TG), and differential thermal analysis (DTA) were used to characterize the light crude oil combustion and kinetics in the presence of copper(I) chloride (CuCl) and magnesium chloride (MgCl2·6H2O). In TG-DTA experiments with magnesium chloride, three reaction regions were identified, known as distillation, low-temperature oxidation (LTO), and high-temperature oxidation (HTO). In the case of copper(I) chloride, two main transitional stages are observed with distillation and high-temperature oxidation (HTO). It was also observed that, as the mol % of magnesium chloride increased, the high-temperature oxidation peak shifted to the lower-temperature region reflecting more homogeneous composition of the solid residue. In the case of reaction cell experiments, it was observed that the molar CO2/CO ratio values of fuel combustion increased with the addition of metallic salts. A decrease in the atomic H/C ratio with an increase in temperature was observed in all experiments performed
In-situ combustion laboratory studies of Turkish heavy oil reservoirs
The purpose of this research was to perform dry and wet forward combustion experiments for Turkish heavy oil reservoirs (Raman, Adiyaman and Çamurlu and Bati Kozluca) under different experimental conditions. In the experiments, a vertical tube was packed with crushed limestone and saturated with crude oil and water. It was observed that peak temperatures were higher when stabilized combustion was achieved and decreased as the combustion front approached the outlet end of the tube. In wet combustion experiments, the rate of combustion reaction and therefore rate of heat generation were reduced with the resultant drop in peak temperatures. In dry and wet combustion experiments, excess carbon-dioxide productions were observed due to the decomposition of carbonate minerals. Atomic H/C ratio of the fuel consumed decreased as the average peak temperature increased. Fuel consumption rate was higher for dry combustion experiments as the °API gravity of the crude oils increased. A decrease is also observed in fuel consumption rate after the water-air ratio value is reached to optimum value. For high water-air ratio in wet combustion experiments, a general decrease was observed as the °API gravity of the crude oils increased
An Investigation of the Applicability of the In-situ Thermal Recovery Technique to the Beypazari Oil Shale
In this research, a 3-D reservoir model for steam recovery was used to study Beypazari oil shale. In addition, the reaction kinetics parameters of Beypazari oil shale were determined by using the Weijdema's reaction kinetics approach in order to evaluate the applicability of these thermal methods. In the analysis of reaction kinetics experiments, two different temperature regions were observed. In the time versus temperature graph, linearly increasing the temperature zone was considered to be the fuel deposition region and the temperature peak is concluded to be the high temperature oxidation. The results demonstrated that the Beypazari oil shales that were studied were suitable for oil production by the in-situ combustion technique (24.00 lt/ton)
THERMAL RESIDUAL STRESSES IN ONE-DIRECTIONAL FUNCTIONALLY GRADED PLATES SUBJECTED TO IN-PLANE HEAT FLUX
This study carries out the transient thermal residual stress analyses of functionally graded clamped plates for different in-plane material compositions and in-plane heat fluxes. The heat conduction and Navier equations representing the two-dimensional thermoelastic problem were discretized using the finite-difference method, and the set of linear equations were solved using the pseudo singular value method. Both in-plane temperature distributions and the heat transfer period were affected considerably by the compositional gradient. The type of in-plane heat flux had a minor effect on the temperature profile, but on the heat transfer period. The high stress levels appeared in the ceramic-rich regions. The normal and equivalent stresses exhibited a sharp change in the plates with ceramic-rich as well as metal-rich compositions, and the concentrated on a narrow ceramic layer. A smooth stress variation was achieved through the graded region with a balanced composition of ceramic and metal-phases, and the stress discontinuities disappeared. The in-plane shear stress was negligible. The equivalent stress exhibited a linear temporal variation for both constant and sinusoidal heat fluxes, but a nonlinear variation for the exponential heat flux. In case the heat flux is applied along the metal edge (metal-to-ceramic plate) instead of the ceramic edge, the displacement and stress components exhibited similar distributions to those of a ceramic-to-metal plate but in the opposite direction. As a result, the distribution of in-plane material composition affects only normal stress distributions, whereas the peak stress levels occur in the ceramic-rich regions. Since the normal stresses concentrate along a narrow ceramic layer for ceramic-rich or metal-rich compositions, a balanced in-plane material composition distribution of ceramic and metal would be useful to avoid probable local ceramic fracture or damage
Thermal Residual Stresses in Adhesively Bonded In-plane Functionally Graded Clamped Plates Subjected to an Edge Heat Flux
In this study we have carried out the thermal residual stress analyses of adhesively bonded functionally graded clamped plates for different edge heat fluxes. The material properties of the functionally graded plates were assumed to vary with a power law along an in-plane direction not through the plate thickness direction. The transient heat conduction and Navier equations describing the two-dimensional thermo-elastic problem were discretized using the finite-difference method, and the set of linear equations was solved using the pseudo singular value method. The plate material properties near the interfaces played an important role in the interfacial adhesive stresses. The compositional gradient affected considerably both in-plane temperature distributions and heat transfer periods. The type of in-plane heat flux had only a minor effect on the temperature profiles but affected both the temperature levels and heat transfer period. Both plates undergo considerable compressive normal strains and stresses, but shear strains were more effective. Peak equivalent strains were observed for a constant heat flux and plates with a metal-rich composition. The compositional gradient and direction played important role in the profiles and levels of normal, shear and equivalent stresses as well as strains. The equivalent stress and strains concentrated along the free edges of the adhesive layer. The adhesive layer experienced a considerable distortional deformation rather than volumetric deformation. The equivalent stress exhibited small changes through the adhesive thickness and along the overlap length. The equivalent stress remained uniform in a large region of the overlap length and increased to a peak level around the free edges of the first plate-adhesive interface, whereas it increased to a peak level in a large region of the overlap length from a minimum level around the free edges of the second plate-adhesive interface. The strains and equivalent strains were higher for a metal-rich material composition. The direction of the material composition of the plates affected both stress and strain levels; thus, the CM-CM and CM-MC plates exhibited lower strain and stress levels than those in the MC-CM and MC-MC plates. However, only the adhesively bonded CM-MC plate configuration could achieve the lowest deformations and stresses in both plates and adhesive layer. (C) Koninklijke Brill NV, Leiden, 201
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