The Effect of Preoperative Three Dimensional Modeling and Simulation on Outcome of Intracranial Aneursym Surgery

Erkin Ozgıray,Bugra Husemoglu,Celal Cınar,Elif Bolat,Nevhis Akınturk,Huseyin Bıceroglu,Ceren Kızmazoglu 대한신경외과학회 2024 Journal of Korean neurosurgical society Vol.67 No.2

Objective : Three-dimensional (3D) printing in vascular surgery is trending and is useful for the visualisation of intracranial aneurysms for both surgeons and trainees. The 3D models give the surgeon time to practice before hand and plan the surgery accordingly. The aim of this study was to examine the effect of preoperative planning with 3D printing models of aneurysms in terms of surgical time and patient outcomes. Methods : Forty patients were prospectively enrolled in this study and divided into two groups : groups I and II. In group I, only the angiograms were studied before surgery. Solid 3D modelling was performed only for group II before the operation and was studied accordingly. All surgeries were performed by the same senior vascular neurosurgeon. Demographic data, surgical data, both preoperative and postoperative modified Rankin scale (mRS) scores, and Glasgow outcome scores (GOS) were evaluated. Results : The average time of surgery was shorter in group II, and the difference was statistically significant between the two groups (p<0.001). However, no major differences were found for the GOS, hospitalisation time, or mRS. Conclusion : This study is the first prospective study of the utility of 3D aneurysm models. We show that 3D models are useful in surgery preparation. In the near future, these models will be used widely to educate trainees and pre-plan surgical options for senior surgeons.

Absorption Spectra and Sunlight Conversion Efficiency in Fullerene bonded Supramolecules on Nanostructured ZnO

Erkin Zakhidov,Abdumutallib Kokhkharov,Vakhobjon Kuvondikov,Sherzod Nematov,Rafael Nusretov 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.7

The efficiency of solar radiation conversion in a model system of artificial photosynthesis, the porphyrin-fullerene assembly, is analyzed. A study of the optical absorption spectra of the porphyrin and the fullerene molecules, as well as their assembly in organic solutions, made it possible to estimate the energy efficiency of the conversion. Numerical values of the energy efficiency, defined as the fraction of the light quantum energy converted to the chemical potential of separated charges, are calculated for low- and high-concentration solutions of such a supramolecular system. The possibility of the efficient utilization of long-wavelength solar radiation in the high-concentration porphyrin-fullerene assembly solution in toluene and benzene is shown. In the photovoltaic system consisting of such a supramolecular active element, a thin ZnO film with a nanostructured surface may be introduced as a secondary acceptor of electrons from fullerene molecules. An enhancement of the transformation of separated charges of the porphyrin-fullerene assembly into electrical current by means of the ZnO film deposited on the surface of the anode electrode in such a heterogenic photovoltaic unit is proposed.

Total gastrosplenectomy with distal pancreatectomy for local advanced gastric adenocarcinoma

Erkin ASHIMOV,Nikolay KISELEV,Hayk TORGOMAYN,Vladimir ZAGAINOV 한국간담췌외과학회 2021 Annals of hepato-biliary-pancreatic surgery Vol.25 No.-

The Helminth Fauna of Lake Frog (Rana ridibunda Pallas, 1771) in Ferghana Valley, Uzbekistan

Erkin F. Ikromov,Jaloliddin A. Azimov,Cho, Myoung-Rae Korean Society of Applied Entomology 2004 Journal of Asia-Pacific Entomology Vol.7 No.2

A survey was conducted on qualitative and quantitative composition of the helminth fauna of the lake frog, Rana ridibunda, in Ferghana Valley, Uzbekistan. Data were collected on the level of infection and its intensity, places and time of findings, index of abundance for 26 helminth species; 10 species of trematodes, 3 species of cestodes, 4 species of acanthocephalans, and 9 species of nematodes. Brief descriptions and drawings are provided for five helminth species first reported from Uzbekistan.

Buckling of symmetrically laminated quasi-isotropic thin rectangular plates

Erkin Altunsaray,İsmail Bayer 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.3

The lowest critical value of the compressive force acting in the plane of symmetrically laminated quasi-isotropic thin rectangular plates is investigated. The critical buckling loads of plates with different types of lamination and aspect ratios are parametrically calculated. Finite Differences Method (FDM) and Galerkin Method are used to solve the governing differential equation for Classical Laminated Plate Theory (CLPT). The results calculated are compared with those obtained by the software ANSYS employing Finite Elements Method (FEM). The results of Galerkin Method (GM) are closer to FEM results than those of FDM. In this study, the primary aim is to conduct a parametrical performance analysis of proper plates that is typically conducted at preliminary structural design stage of composite vessels. Non-dimensional values of critical buckling loads are also provided for practical use for designers.

Efficacy of magnetic resonance imaging for diagnosis of penile fracture: A controlled study

Erkin Saglam,Fatih Tarhan,Mustafa B. Hamarat,Utku Can,Alper Coskun,Emre Camur,Kemal Sarica 대한비뇨의학회 2017 Investigative and Clinical Urology Vol.58 No.4

Purpose: To evaluate the diagnostic value of magnetic resonance imaging (MRI) in patients with suspected penile fracture. Materials and Methods: A total of 122 patients admitted to our inpatient clinic with a suspicion of penile fracture following a recent history of penile trauma and who underwent surgical exploration were included this study. A thorough physical examination, a detailed medical history, description of the trauma, and preoperative International Index of Erectile Function (IIEF) scores were obtained for each patient prior to surgery. Thirty-eight of these patients were evaluated with MRI before the surgical exploration. Intraoperative findings were also recorded. Physical findings and IIEF scores were also recorded at postoperative 6 months. Results: The mean age of our patient group was 36.5±12.3 years. Penile fracture was detected in 105 of 122 patients in whom surgical exploration was performed owing to a suspected diagnosis. The mean time interval from penile trauma to hospital admittance was 9.9±15.1 hours. No cavernosal defect was detected in 9 of 84 patients (10.7%) who were not evaluated with MRI prior to surgery. Compared with surgical exploration, MRI findings showed 100% (30 of 30) sensitivity and 87.5% (7 of 8) specificity in the diagnosis of penile fracture. MRI had a high negative predictive value of 100% (7 of 7) and a positive predictive value of 96.7% (30 of 31) with just 1 misdiagnosed patient. Conclusions: MRI is a reliable diagnostic tool in the diagnosis of penile fractures. Compared to history and physical findings taken all together, the high sensitivity and specificity of this imaging technique can decrease the number of unnecessary surgical explorations.

Free vibration of symmetrically laminated quasi-isotropic super-elliptical thin plates

Erkin Altunsaray 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.4

Free vibration analysis of super-elliptical composite thin plates was investigated. Plate is formed by symmetrical quasi-isotropic laminates. Rayleigh-Ritz method was used for parametric analysis based on the governing differential equations of Classical Laminated Plate Theory (CLPT). Simply supported and clamped boundary conditions at the periphery of plates were considered. Parametric study was performed for the effect of different lamination type, aspect ratio, thickness and super-elliptical power on natural frequencies. Convergence study and validation of isotropic case were achieved. A number of design parameters like different dimensions, structure systems, panel sizes, panel thicknesses, lamination sequences, boundary conditions and loading conditions must be considered in the production of composite ships. The number of possible combinations practically may be so high that a parametric study should be carried out in order to determine the optimum design parameters rapidly during the preliminary design stage. The use of Rayleigh-Ritz method could make this parametric study possible. Thereby it might be decreasing the consumption of time, material and labor. Certain results for some different super-elliptical powers presented in tabulated form in Appendix for designers as well.

On New Representatives of the Helminth Fauna of Reptiles (Testudines and Sauria) in Uzbekistan

Erkin F. Ikromov,Cho, Myoung-Rae Korean Society of Applied Entomology 2004 Journal of Asia-Pacific Entomology Vol.7 No.1

In a survey on parasitic helminthes of reptiles comprising 8 species under the orders of Testudines and Sauria in different areas of the plain land and foothill zones of the Ferghana Valley of Uzbekistan from 1993 through 2001, 14 species of parasitic helminthes comprising 2 cestode and 12 nematode species new to the fauna of Uzbekistan were found. List of hosts by parasitic helminthes, extensiveness and intensity of the infection, the time and sites of findings of the helminthes are reported with brief descriptions and drawings of the female nematodes of Parapharhyngodon szczerbaki Radchenko et Shapiro, 1975, Mehdiella hamosa Forstner, 1960 and the male of Abbreviata schulzi Markov et Bogdanov, 1961.

Brown Tumor of the Thoracic Spine : First Manifestation of Primary Hyperparathyroidism

Sonmez, Erkin,Tezcaner, Tugan,Coven, Ilker,Terzi, Aysen The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.58 No.4

Brown tumors also called as osteoclastomas, are rare nonneoplastic lesions that arise in the setting of primary or secondary hyperparathyroidism. Parathyroid adenomas or hyperplasia constitute the major Brown tumor source in primary hyperparathyroidism while chronic renal failure is the leading cause in secondary hyperparathyroidism. Most of the patients with the diagnosis of primary hyperparathyroidism present with kidney stones or isolated hypercalcemia. However, nearly one third of patients are asymptomatic and hypercalcemia is found incidentally. Skeletal involvement such as generalized osteopenia, bone resorption, bone cysts and Brown tumors are seen on the late phase of hyperparathyroidism. The symptoms include axial pain, radiculopathy, myelopathy and myeloradiculopathy according to their locations. Plasmocytoma, lymphoma, giant cell tumors and metastates should be ruled out in the differential diagnosis of Brown tumors. Treatment of Brown tumors involve both the management of hyperparathyroidism and neural decompression. The authors report a very rare spinal Brown tumor case, arisen as the initial manifestation of primary hyperparathyroidism that leads to acute paraparesis.

Pulsed Electric Current Sintering of the Al₂O₃ - 15wt% ZrO₂ Nanocomposites with 3wt% of Different Solid Lubricants

Cura, M. Erkin,Kim, Seung Ho,Cho, Sung Hun,Suhonen, Tomi,Muukkonen, Tatu,Vaajoki, Antti,Sö,derberg, Outi,Kanerva, Ulla,Lee, Soo Wohn,Hannula, Simo Pekka Trans Tech Publications, Ltd. 2011 Materials science forum Vol.695 No.-

<P>High temperature low friction materials are sought for use in engines in order to reduce energy consumption of the machines. Due to the high service temperatures solid lubricating materials are necessary. This study is designed to find the optimal processing conditions for preparing these materials by pulsed electric current sintering. In this study, the Al2O3- 15wt% ZrO2(AZ) nanocomposite was modified with 3 wt% of self-lubricating component (CaF2, BaF2, MoS2, WS2, h-BN, or graphite). After the preparation of the alumina-zirconia powder mixture solid lubricant powder was added. Powders were then mixed in ethanol for 24 h, dried in a rotary evaporator, and in oven at 80°C for 24 h. The particle size distribution of the powders was established with the laser method. Powders were compacted by using pulsed electric current sintering technique at 1300 °C with 50 MPa for 5 min in vacuum. The structure of the materials was studied with XRD and SEM. Density of the compacts was measured with the Archimedes method and their hardness was evaluated by applying HV1 hardness with the instrumented indentation techniques. Their mechanical behavior was further studied with the instrumented scratch testing.</P>