Bulunan: 5 Adet 0.002 sn
Koleksiyon [12]
Tam Metin [2]
Yayın Türü [1]
Yazar [20]
Yayın Yılı [5]
Konu Başlıkları [20]
Yayıncı [3]
Yayın Dili [1]
Dergi Adı [5]
Synthesis of block/graft copolymers based on vinyl benzyl chloride via reversible addition fragmentation chain transfer (RAFT) polymerization using the carboxylic acid functionalized Trithiocarbonate

Hazer, Baki | Arslan, Hülya | Senemoğlu, Yetkin | Şen, Şadi

Article | 2019 | Journal of Polymer Research26 ( 5 )

Reversible Addition-Fragmentation Chain-Transfer (RAFT) polymerization of styrene (St), vinyl benzyl chloride (vbc), tert-butyl methacrylate (tertBMA) and n-butyl methacrylate (nBMA) was investigated using carboxylic acid functionalized trithiocarbonate (R2). A series of random copolymer of styrene and vinyl benzyl chloride was prepared in order to control chloromethyl functionality in the copolymer, via RAFT polymerization. Addition to this, first-order kinetic behavior of the RAFT polymerization of vbc using R2 was also evaluated. A novel series of amphiphilic copolymers based on polyethylene glycol (PEG) with molar masses of 500 . . .and 2000 g/mol, functionalized polyvinyl benzyl chloride (Pvbc) were obtained via the Williamson-ether-synthesis. As chloromethyl functionality increases, the introduced PEG increases. Fractional precipitation, thermal properties and water uptakes of the amphiphilic polymer samples were evaluated. The new polymers can be the promising materials with high aqueous solubility capacity. © 2019, The Polymer Society, Taipei Daha fazlası Daha az

Antimicrobial effect of polymer-based silver nanoparticle coated pedicle screws: Experimental research on biofilm inhibition in Rabbits

Hazer, Derya Burcu | Sakar, Mustafa | Dere, Yelda | Altınkanat, Gülşen | Ziyal, M. İbrahim | Hazer, Baki

Article | 2016 | Spine41 ( 6 )

Study Design. Antimicrobial effect of a novel silverimpregnated pedicle screw in rabbits. Objective. A novel spine implant model was designed to study the antimicrobial effect of a modified Titanium (Ti) pedicle screws with methicillin-resistant Staphylococcus aureus (MRSA) in multiple surgical sites in the lumbar spine of a rabbit. Summary of Background Data. Infection in spinal implant is of great concern. Anti-infection strategies must be tested in relevant animal models that will lead to appropriate clinical studies. Methods. Fourteen New Zealand white rabbits were divided into 2 groups: group 1: infected unmodified Ti screw gro . . .up (n=6), and group 2: infected polyethylene glycol grafted, polypropylene-based silver nanoparticle (PP-g-PEG-Ag) covered Ti screw group (n=6), and 2 rabbits as sterile (sham-operated and control) group. In all groups, left L4-right L6 vertebra levels were exposed and screws were drilled to transverse processes after contamination of burr holes and surrounding tissue with 0.1mL of 106 colony forming units (CFU) MRSA solutions in groups 1 and 2. After 21 days, samples were collected and infection was analyzed via light and scanning electron microscopy and culturing. Silver nanoparticles (Ag-NP) on the screws and tissues were assayed pre and postoperatively. Results. The bacterial colony count for modified-Ti screw group was lower than for unmodified Ti screw (17.2 versus 200 x 103 CFU/mL, P=0.029) with less biofilm formation. There was no difference in duration of surgery among groups and within the surgical sites. Ag-NPs were detected on the screw surface postoperatively. Conclusion. This novel experimental design of implantation in rabbits is easy to apply and resembles human stabilization technique. Modified Ti screws were shown to have antimicrobial effect especially inhibiting the biofilm formation. This anchored Ag NPs that remained after 21st day of implantation shows that it is resistant to tapping forces of the screw. © 2016 Wolters Kluwer Health, Inc. All rights reserved Daha fazlası Daha az

Synthesis and characterization of novel comb-type amphiphilic graft copolymers containing polypropylene and polyethylene glycol

Balcı, Murat | Allı, Abdulkadir | Hazer, Baki | Güven, Olgun | Cavicchi, Kevin | Çakmak, Mükerrem

Article | 2010 | Polymer Bulletin64 ( 7 ) , pp.691 - 705

Effects of polymer-based, silver nanoparticle-coated silicone splints on the nasal mucosa of rats

Şevik Eliçora, Sultan | Erdem, Duygu | Dinç, Aykut Erdem | Altunordu Kalaycı, Özlem | Hazer, Baki | Yurdakan, Gamze | Külah, Canan

Article | 2017 | European Archives of Oto-Rhino-Laryngology274 ( 3 ) , pp.1535 - 1541

Infection is a serious complication after nasal packing that otolaryngologists seek to avoid. The aim of this study is to investigate the use of silver (Ag) nanoparticle, which serves as antimicrobial agents, with nasal tampons. The study design is an experimental animal model and the setting is tertiary referral center. Twenty-four rats were randomized into the following four groups: (1) control group (n = 6); (2) silicone nasal splint (SNS) group (n = 6); (3) polypropylene-grafted polyethylene glycol (PP-g-PEG) amphiphilic graft copolymer-coated SNS group (n = 6); and (4) Ag nanoparticle-embedded PP-g-PEG (Ag-PP-g-PEG) amphiphilic . . . graft copolymer-coated SNS group (n = 6). These tampons were applied to rats for 48 h, after which they were removed in a sterile manner, and the rats were sacrificed. The nasal septa of the rats were excised, and assessments of tissue changes in the nasal mucosa were compared among the groups. The removed tampons were microbiologically examined, and quantitative analyses were made. When the groups were compared microbiologically, there were no significant differences in bacterial colonization rates of coagulase-negative Staphylococcus spp. among the three groups (p = 0.519), but there was a statistically significant difference among bacterial colonization rates of Heamophilus parainfluenzae and Corynebacterium spp. (p = 0.018, p = 0.004). We found that H. parainfluenzae grew less robustly in the Ag-PP-g-PEG than the PP-g-PEG group (p = 0.017). However, we found no significant difference between the Ag-PP-g-PEG and SNS groups, or between the SNS and PP-g-PEG groups. The growth of Corynebacterium spp. did not differ significantly between the Ag-PP-g-PEG and SNS groups (p = 1.000). When Group 4 was compared with Group 2, the former showed less inflammation. Compared with other tampons, Ag-PP-g-PEG amphiphilic graft copolymer-coated silicone nasal tampons caused less microbiological colonization and inflammation. Therefore, the use of these tampons may prevent secondary infections and reduce the risk of developing complications by minimizing tissue damage. © 2016, Springer-Verlag Berlin Heidelberg Daha fazlası Daha az

The efficacy of silver-embedded polypropylene-grafted polyethylene glycol-coated ventricular catheters on prevention of shunt catheter infection in rats

Hazer, Derya Burcu | Mut, Melike | Dinçer, Nazmiye | Sarıbaş, Zeynep | Hazer, Baki | Özgen, Tunçalp

Article | 2012 | Child's Nervous System28 ( 6 ) , pp.839 - 846

Purpose: Catheter-related infection is a major complication of ventriculoperitoneal shunt in children. The aim of this study is to determine inflammatory response and the efficacy of polypropylene-grafted polyethylene glycol (PP-g- PEG) copolymer and silver nanoparticle-embedded PP-g- PEG (Ag-PP-g-PEG) polymer-coated ventricular catheters on the prevention of catheter-related infections on a new experimental model of ventriculoperitoneal shunt in rats. Methods: Thirty six Wistar albino rats were divided into six groups: group 1, unprocessed sterile silicone catheterembedded group; group 2, sterile PP-g-PEG-coated catheter group; gro . . .up 3, sterile Ag-PP-g-PEG-coated catheter group; group 4, infected unprocessed catheter group; group 5, infected PP-g-PEG-coated catheter group; and group 6, infected Ag-PP-g-PEG-coated catheter group, respectively. In all groups, 1-cm piece of designated catheters were placed into the cisterna magna. In groups 4, 5, and 6, all rats were infected with 0.2 mL of 10×106 colony forming units (CFU)/mL Staphylococcus epidermidis colonies before the catheters were placed. Thirty days after implantation, bacterial colonization in cerebrospinal fluid and on catheter pieces with inflammatory reaction in the brain parenchyma was analyzed quantitatively. Results: Sterile and infected Ag-PP-g-PEG-covered groups revealed significantly lower bacteria colony count on the catheter surface (ANOVA, 0±0, p<0.001; 1.08±0.18, p< 0.05, respectively). There was moderate inflammatory response in the parenchyma in group 4, but in groups 5 and 6, it was similar to that of the sterile group (ANOVA, 16.33± 3.02, p<0.001; 4.00±0.68, p<0.001, respectively). Conclusions: The PP-g-PEG, especially Ag-PP-g-PEG polymer-coated ventricular catheters are more effective in preventing the catheter-related infection and created the least inflammatory reaction in the periventricular parenchyma. © Springer-Verlag 2012 Daha fazlası Daha az

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