Lumbar Epidural Varix Mimicking Disc Herniation

Bursali, Adem,Akyoldas, Goktug,Guvenal, Ahmet Burak,Yaman, Onur The Korean Neurosurgical Society 2016 Journal of Korean neurosurgical society Vol.59 No.4

Lumbar radiculopathy is generally caused by such well-recognized entity as lumbar disc herniation in neurosurgical practice; however rare pathologies such as thrombosed epidural varix may mimic them by causing radicular symptoms. In this case report, we present a 26-year-old man with the complaint of back and right leg pain who was operated for right L4-5 disc herniation. The lesion interpreted as an extruded disc herniation preoperatively was found to be a thrombosed epidural varix compressing the nerve root preoperatively. The nerve root was decompressed by shrinking the lesion with bipolar thermocoagulation and excision. The patient's complaints disappeared in the postoperative period. Thrombosed lumbar epidural varices may mimic lumbar disc herniations both radiologically and clinically. Therefore, must be kept in mind in the differential diagnosis of lumbar disc herniations. Microsurgical techniques are mandatory for the treatment of these pathologies and decompression with thermocoagulation and excision is an efficient method.

Approximation by Means of Fourier Trigonometric Series in Weighted Orlicz Spaces

Guven,Israfilov 장전수학회 2009 Advanced Studies in Contemporary Mathematics Vol.19 No.2

The order of approximation of Cesaro, Zygmund and Abel-Poisson means of Fourier trigonometric series were estimated by the modulus of continuity in re‡exive weighted Orlicz spaces with Muckenhoupt weights. These results were applied to estimate the rate of approximation of Cesaro, Zygmund and Abel sums of Faber series in weighted Smirnov-Orlicz classes de…ned on simply connected domains of the complex plane.

The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats

Guven, Mustafa,Akman, Tarik,Yener, Ali Umit,Sehitoglu, Muserref Hilal,Yuksel, Yasemin,Cosar, Murat The Korean Neurosurgical Society 2015 Journal of Korean neurosurgical society Vol.57 No.5

Objective : The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuro-protective effects of kefir on spinal cord ischemia injury in rats. Methods : Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. Results : The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (p<0.05). Catalase and superoxide dismutase levels of the kefir group were significantly higher than ischemia group (p<0.05). In histopathological samples, the kefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (p<0.05). In immunohistochemical staining, hipoxia-inducible factor-$1{\alpha}$ and caspase 3 immunopositive neurons were significantly decreased in kefir group compared with ischemia group (p<0.05). The neurological deficit scores of kefir group were significantly higher than ischemia group at 24 h (p<0.05). Conclusion : Our study revealed that kefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

Behavior and design of stainless steel tubular member welded end connections

Guven Kiymaz,Edip Seckin 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.3

Among the various alternatives to make a steel tubular member connection, making a slotted and gusset plate welded connection is one of the most frequently preferred alternatives. This type of connection is essentially an end connection that is made by slotting the tube longitudinally, inserting the gusset plate and then placing longitudinal fillet welds at the tube-to-plate interface. In this paper an experimental study on the behaviour of such connections in stainless steel is presented. 24 specimens were tested under concentrically applied axial tensile forces for varying tube-to-gusset plate weld lengths. Both circular and box section members were considered in the test program. Load-deformation curves were obtained and comparisons were made in terms of strength and ductility. The results obtained from the study were then critically examined and compared with currently available design guidance for slotted gusset plate welded tubular end connections. It is noted that no specific rules exist in international specifications on structural stainless steel which cover the design of such connections. Therefore, the results of this study are compared with the existing design rules for carbon steel.

MULTIPLIER THEOREMS IN WEIGHTED SMIRNOV SPACES

Guven, Ali,Israfilov, Daniyal M. Korean Mathematical Society 2008 대한수학회지 Vol.45 No.6

The analogues of Marcinkiewicz multiplier theorem and Littlewood-Paley theorem are proved for p-Faber series in weighted Smirnov spaces defined on bounded and unbounded components of a rectifiable Jordan curve.

Comparison of retention forces with various fabrication methods and materials in double crowns

Guven, Melahat Celik,Tuna, Meral,Bozdag, Ergun,Ozturk, Gizem Nur,Bayraktar, Gulsen The Korean Academy of Prosthodonitics 2017 The Journal of Advanced Prosthodontics Vol.9 No.4

PURPOSE. The purpose of this study was to analyze the retention force changes and wear behaviours of double-crown systems over long-term use. MATERIALS AND METHODS. Ten groups, each consisting of six samples, were evaluated. Specifically, casting gold alloy primary crown - casting gold alloy secondary crown (AA), laser sintering primary crown - laser sintering secondary crown (LL), casting Cr alloy primary crown - casting Cr alloy secondary crown, (CC) zirconia primary crown - electroformed secondary crown (ZA), and CAD/CAM titanium alloy primary crown - CAD/CAM titanium alloy secondary crown (TT) groups were evaluated at cone angles of $4^{\circ}$ and $6^{\circ}$. The samples were subjected to 5,000 insertion-separation cycles in artificial saliva, and the retention forces were measured every 500 cycles. The wear levels were analyzed via SEM at the beginning and end of the 5,000 cycles. RESULTS. In all samples, the retention forces increased when the conus angle decreased. The highest initial and final retention force values were found in the $LL-4^{\circ}$ group (32.89 N-32.65 N), and the lowest retention force values were found in the $ZA6^{\circ}$ group (5.41 N-6.27 N). The ZA groups' samples showed the least change in the retention force, and no wear was observed. In the other groups, wear was observed mostly in the primary crowns. CONCLUSION. More predictable, clinically relevant, and less excursive retention forces can be observed in the ZA groups. The retention force values of the LL groups were statically similar to those of the other groups, except the ZA groups.

Multiplier theorems in weighted Smirnov spaces

Ali Guven,Daniyal M. Israfilov 대한수학회 2008 대한수학회지 Vol.45 No.6

The analogues of Marcinkiewicz multiplier theorem and Littlewood- Paley theorem are proved for p-Faber series in weighted Smirnov spaces defined on bounded and unbounded components of a rectifiable Jordan curve. The analogues of Marcinkiewicz multiplier theorem and Littlewood- Paley theorem are proved for p-Faber series in weighted Smirnov spaces defined on bounded and unbounded components of a rectifiable Jordan curve.

Evaluation and comparison of the marginal adaptation of two different substructure materials

Sedat Guven,Veysel Eratilla,Ebru Sumer,Ali Ihsan Zengingul,Sabiha Zelal Ulku,Tahir Karaman 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.3

PURPOSE In this study, we aimed to evaluate the amount of marginal gap with two different substructure materials using identical margin preparations. MATERIALS AND METHODS Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson's correlation analysis was also performed to assess relationships between variables. RESULTS According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 ± 5.82 µm before and 35.11 ± 6.52 µm after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 ± 8.87 µm before and 69.33 ± 9.03 µm after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface. CONCLUSION Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.

Erratum: Predictive factors associated with successful response to ultrasound guided genicular radiofrequency ablation

Selin Guven Kose,Halil Cihan Kose,Feyza Celikel,Omer Taylan Akkaya The Korean Pain Society 2023 The Korean Journal of Pain Vol.36 No.4

Ultrasound-guided PENG block versus intraarticular corticosteroid injection in hip osteoarthritis: a randomised controlled study

Selin Guven Kose,Halil Cihan Kose,Feyza Celikel,Serkan Tulgar,Omer Taylan Akkaya 대한통증학회 2023 The Korean Journal of Pain Vol.36 No.2

Background: This study aimed to compare the effectiveness of the pericapsular nerve group (PENG) block and intra-articular injection (IAI) of steroid-bupivacaine in the treatment of hip osteoarthritis (OA). Methods: After randomization, patients received either a PENG block or IAI under ultrasound-guidance. Clinical evaluations were recorded at baseline, day 1, and weeks 1, 4, and 8 post-intervention. The numerical rating scale (NRS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Harris Hip Scale (HHS) scores, pain medication use determined by a quantitative analgesic questionnaire, and patient satisfaction were evaluated. Results: Sixty patients were included in this study. NRS scores improved significantly for both groups during the follow-up compared to pretreatment (P < 0.001), with better pain scores for the PENG group (P < 0.001) at day 1 with larger effect size (Cohen’s d = 4.62), and IAI group at 4 (Cohen’s d = 5.15) and 8 (Cohen’s d = 4.33) weeks (P < 0.001). There was no significant difference in pain medication consumption (P = 0.499) and patient satisfaction (P = 0.138) between groups. Patients in the IAI group experienced significant improvement in HHS (Cohen’s d = 2.16, P = 0.007) and WOMAC (Cohen’s d = 1.02, P = 0.036) scores at 8 weeks compared to the PENG group. Conclusions: The ultrasound-guided PENG block provides effective pain relief which improves functionality and quality of life in hip OA patients up to 2 months. The PENG block can be considered an easy, safe, and useful alternative treatment modality for hip OA.