Zonguldak Karaelmas University

About: Zonguldak Karaelmas University is a based out in . It is known for research contribution in the topics: Population & Copolymer. The organization has 1939 authors who have published 4296 publications receiving 62466 citations.

Bacterial translocation in experimental stroke: what happens to the gut barrier?

Abstract: The reasons of post-stroke infections are still incompletely understood Bacterial translocation (BT), the passage of viable microbes across an even anatomically intact intestinal barrier, has been described in many critical illnesses To date, it has not been studied as a source of infection in an animal stroke model To address this, a permanent left middle cerebral artery occlusion (MCAO) model in rats was used After 24, 48, and 72 hours (h), sham and experimental groups were sacrificed and samples were taken for BT Similarity between bacteria detected in tissues (blood, mesenteric lymph node, liver, spleen, and lung) and intestinal microflora was shown with phenotypic methods and antibiotyping Possible ileum tissue injuries were shown by histopathologic examination (including morphometric analysis) Although there was no bacterial proliferation in the sham groups, 555%, 454%, and 30% bacterial proliferation was detected in MCAO groups at postoperative hour 24, 48, and 72, respectively In MCAO groups the bacterial proliferation in tissues and ileum tissue injury scores were higher over time compared to sham groups (p < 005) Our findings support the view that stroke, itself leads to mucosal damage and bacterial translocation (Tab 5, Fig 2, Ref 27)

Improved User Fairness in Decode-Forward Relaying Non-Orthogonal Multiple Access Schemes With Imperfect SIC and CSI

Abstract: Non-orthogonal multiple access (NOMA) is one of the key technologies to serve in ultra-dense networks with massive connections which is crucial for Internet of Things. Besides, NOMA provides better spectral efficiency compared to orthogonal multiple access. However, NOMA systems have been mostly investigated only in terms of ergodic capacity (EC) and outage probability (OP) whereas error performances have not been well-studied. In addition, in those analysis, mostly perfect successive interference canceler (SIC) is assumed or the considered imperfect SIC model is not reasonable. Besides, channel state information (CSI) errors are also not considered in most studies. However, this is not the case for the practical scenarios, and these imperfect SIC and CSI effects limit the performance of NOMA involved systems. Moreover, the imperfect SIC causes unfairness between users. In this paper, we introduce reversed decode-forward relaying NOMA (R-DFNOMA) to improve user fairness compared to conventional DFNOMA (C-DFNOMA). In the analysis, we define imperfect SIC effect as dependant to channel fading and with this imperfect SIC and CSI errors, we derive exact expressions of EC and OP. We also provide upper bound for EC, and asymptotic and lower bound expressions for OP. Furthermore, we evaluate bit error performance of the proposed R-DFNOMA and derive exact bit error probability (BEP) in closed-form with imperfect CSI which is the first study analyzing error performances of decode-forward relaying NOMA with imperfect CSI. Then, we define user fairness index in terms of all key performance indicators (KPIs) (i.e., EC, OP and BEP). Based on extensive simulations, all derived expressions are validated, and it is proved that the proposed R-DFNOMA provides better user fairness than C-DFNOMA in terms of all KPIs. Finally, we discuss the effect of power allocations at both source and relay on the performance metrics and user fairness.

Effect of surface sealant agents on the surface roughness and color stability of denture base materials

Abstract: Statement of problem The effects of surface sealant agents on the surface roughness and color stability of denture base materials are unknown. Purpose The purpose of this in vitro study was to evaluate the effects of different polishing methods on the surface roughness and color stability of denture base materials. Material and methods A total of 120 specimens were fabricated from 2 poly(methyl methacrylate) (PMMA) and 1 polyamide denture base materials and divided into 4 groups (n=10 in each group) according to the applied surface treatment procedure: conventional polishing (control) and 3 surface sealant coupling methods. Surface roughness average (R a ) values were measured using a profilometer. Color parameters were measured using a spectrophotometer before and after being stained with coffee. Color differences (CIEDE 2000 [ΔE 00 ]) were calculated. Data were statistically analyzed using 2-way ANOVA and Tukey honest significant difference test (α=.05). Results No statistically significant difference were found between surface roughness values of the control and those of the specimens treated using a surface sealant agent ( P >.05). The highest color difference was calculated for the polyamide control group. Statistically significant differences were found between the control group and the group treated with the polyamide surface sealant agent ( P Conclusions All specimens had a surface roughness value higher than the plaque accumulation threshold (0.20 μm). The color changes observed were clinically unacceptable, except for conventionally polished and one type of surface sealant applied microwave polymerized PMMA denture base material.

Hydroxylation of pendant vinyl groups of poly(3-hydroxy undec-10-enoate) in high yield

Abstract: Poly(3-hydroxy undec-10-enoate) (PHU) was synthesized by feeding Pseudomonas oleovarans with 10-undecenoic acid and nearly 100% hydroxylation of double bonds of PHU was achieved by hydroboration–oxidation reaction using 9-borobicyclononane. The disappearance of vinyl signals of PHU in proton and 13C NMR spectra was observed. Acetylation of hydroxylated PHU was conducted for molecular weight measurements. Molecular weight and polydispersity of hydroxylated PHU were found to be 10,000 and 1.23, respectively, while that of the originals was 32,000 and 2.42. Decomposition temperatures of original and hydroxylated PHU were 280 and 200°C, respectively. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2132–2139, 2005