Structural changes in the side branches and the circle of Willis following the use of flow-diverting stents

Background/aim: This study aimed to evaluate the diameter and flow changes in the circle of Willis and side branches following the use of FDSs extending from the middle cerebral artery (MCA) to the internal carotid artery (ICA) for the treatment of aneurysms in the terminal segment of ICA, and the clinical results. Material and method: This study was conducted in a single center between January 2012 and April 2018 in patients with the anterior choroidal artery (AChoA), the posterior communicating artery (PComA), and the ICA terminal segment aneurysms treated with the FDSs. The changes in aneurysm size, arterial structures covered by the FDSs, and changes in the diameter and flow in arteries forming the circle of Willis were retrospectively analyzed. Results: Fourteen patients with a total of 25 aneurysms treated with FDSs extending from MCA to ICA were evaluated. The mean aneurysm fundus size was 5.14 mm (range 1.5–22 mm). Before treatment, the anterior communicating artery (AComA) was patent in all patients. Implanted FDSs covered the anterior cerebral artery (ACA) and AChoA in all patients (100%), nonhypoplasic PComA in two patients (14.28%), and the ophthalmic artery in nine (64.3%). The mean follow-up time was 36.78 ± 22.44 months. In follow-up, there was a decrease in the mean ipsilateral ACA A1 segment diameter from 1.99 ± 0.58 cm to 1.81 ± 0.31 cm (p = 0.01). The mean contralateral A1 segment diameter increased from 1.66 ± 0.48 cm to 1.93 ± 0.42 cm (p = 0.004). All aneurysms were totally occluded. Conclusion: If the AComA is patent, ipsilateral anterior circulation can be compensated through modifications in the contralateral ACA A1 segment in patients with ICA terminal segment aneurysms treated with FDSs extended from MCA to ICA and covering ACA. Although covering the anterior choroidal and lenticulostriate arteries by FDSs, ischemic complications may not occur frequently. Thus, this effective therapy can be applied more safely

Light microscopic analysis of the effects of gd-dtpa dimeglumine and iopromide on rabbit hyaline cartilage and synovial membrane

Bu çalişmanin amaci kontrastli maddelerin eklem kikirdaği ve sinoviyal membran üzerine olan etkilerini tavşan modelinde araştirmaktir. Çalişmada 60 tavşan dizi kullanildi. Kontrastli ajan olarak iopromid ve Gd-DTPA diz eklemlerine intraartiküler uygulanarak 1. saat, 1.gün, 1.hafta ve 2.hafta sonra sinoviyal membran ve hiyalin kikirdak üzerine olan histolojik etkileri işik mikroskobisi yardimi ile incelendi. Kontrol grubu olarak serum fizyolojik kullanildi. iopromid ve Gd-DTPAuygulanmasindan sonra sinoviyal membranda hiperemi, hemoraji ve yüzeyel stromada vakuollü hücre artişina rastlandi. Hiyalin kikirdakta ise proliferasyon, hipertrofi ve yoğun glikojen birikimi, piknoz ve GlikozAmino Glikan boyanma azliğina neden olduğu görüldü. Bu etkilerin 2. hafta sonunda azalarak devam ettiği saptandi. Çalişmamizda kullanilan maddelerin uygulama süreleri boyunca eklem kikirdağina ve sinoviyal membran üzerine olan etkilerinin istatistiksel olarak anlamli olduğu gösterilememiştir (p>0.05).The aim of this study is to assess the effects of contrast agents on hyaline cartilage and synovial membrane in a rabbit model. Light microscopic analysis of the effects of intraarticular Iopromide and Gd-DTPA on synovial membrane and hyaline cartilage at 1st hour, 1st day, 1st week and 2nd week was performed. NaCl%0.9 was used as control. Hyperemia, hemorhage and increase in the vacuolised cell number in the superficial stroma were observed in the synovial membrane. Proliferation, hypertrophy, dense glycogen storage, pycnosis and decrease in glycosaminoglycan (GAG) staining were observed in the hyaline cartilage. These effects lessened in two weeks. We were not able to demonstrate that contrast agents have any significant effect on hyaline cartilage and synovial membrane (p>0.05)

Hasarlı Çene Kemiklerinde Abutment Boyunun Dental İmplant Sistemi Üzerindeki Etkileri

The purpose of this study is to investigate the stresses occurred onhard and soft bones after recovering the deficiency caused by totally edentulousand damaged mandible by using abutments with different lengths andprosthesis filling material. Two different damaged parts of 2.5 and 4.5 mm indepth were created with the aid of Solidworks program on the right hand sideof the mandible. Implants were then applied between the foremen channels.Later, the damaged models were recovered by abutment with different lengthsas for the first method. Two models using abutment were, therefore, obtainedfor the damaged parts of 2.5 and 4.5 mm in depth. In the second method, for thesame damaged cases, prosthesis filling material was used to recover deficiencykeeping the abutment length constant. Finally, there were totally obtained 4different damaged models of two fixed with abutment and two fixed with fillingmaterial and 1 undamaged model. At the second step of this study, the stressvalues were obtained on lower jaw bones by using finite element method underthe maximum chewing force and compared to each other. The results showedthat stress data obtained particularly on the soft and hard bones weredistributed more uniformly on the damaged models fixed with prosthesis fillingmaterial compared to the damaged models recovered by abutment. Moreover,the stress values obtained for models fixed with different abutment length wererather high in comparison to those of the filling material applicatio

INVESTIGATION OF DAMPENED SYSTEM AND DRY OFFSET PRINTING TECHNIQUES AND COMPARISON OF REPRODUCTION RESULTS

Printing ; is the process of reproduction rapid transfering of the images, inscriptions, figures and graphics on to a surface in the original format. The dampened system offset printing is the smooth printing system. Smooth printing is based on the principal of repelling of the water by the oil inside the ink and not to be mixed with. The printed and unprinted surfaces on the plate has a chemical characteristic. The process of printing occurs in the way that. The unprinted areas captures water and repell ink, the printed areas captures ink and repell water.The dry offset system is; the combination of the flexo and dampened system offset methods. In the method the relief part of the plate transfers the image to the smooth surfaced rubber printing cylinder and the image is transferred to the material by the cylinder. Water is not needed for humidification. So the plate is not wetted before printing. The pictures or positive dias are not printed by dry ofset method but, the hand dravings, very detailed desings and quite small texts could be printed to the range of six colors. In this study, an evaluation of the comparison of the process stages and reproduction results of the two techniques is conducted

Evaluation of articular eminence pneumatization using cone beam computed tomography

Aim. Knowledge about the anatomy of the temporomandibular joint (TMJ) and its surrounding structures is mandatory for success in surgical interventions and for understanding the pathway of spread of infections in this region. This study aims to investigate the anatomy and morphology of pneumatized articular eminence (PAT) using cone beam computed tomography (CBCT) imaging in a group of patients. Methods. A retrospective study on 825 patients (377 males, 448 females) aged between 18 and 91 years was performed using sagittal and coronal CBCT images. PAT was defined as non-expansile, nondestructive cyst-like radiolucency in the zygomatic process of the temporal bone, which appears similar to the mastoid air cells. It was classified in two groups as unilocular and multilocular. Statistical comparison of gender, age and localization was performed using chi-square test and correspondence analysis. P0.05). Conclusion. Pneumatization of the articular eminence is a challenging entity for TMJ surgery and spread of infections in this region. Practitioners who are dealing with TMJ surgery and pathology should have detailed information about this anatomical variation since it may cause serious complications

Prospective science teachers conceptual understanding about proteins and protein synthesis

In present study, it was aimed to determine the effects of traditional teaching on levels of conceptual understanding of prospective science teachers on protein and protein synthesis before, after and six months after of instruction. Firstly, according to the views of the expert in the area, concept analysis was carried out about protein and protein synthesis. Considering the concept analysis, a six-item conceptual understanding test was prepared and administered as the pre-test, post-test and delayed post-test. As a result of the study, it was determined that the prospective science teachers had some difficulties in understanding concepts about protein and protein synthesis and traditional instruction was insufficient to overcome these problems. Especially, it was revealed that the candidates had severe misconceptions about process of protein synthesis and structure of protein. Finally, some suggestions were presented with the support of the findings obtained from this study. © 2007 Asian Network for Scientific Information

Dönerci Hacıbaba

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2014.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Yeni, Harun