Browsing by Author "Arslan N."

Now showing 1 - 8 of 8
  • No Thumbnail Available
    Item
    Current therapeutic approaches in childhood chronic hepatitis B infection: A multicenter study
    (Blackwell Publishing, 2004) Dikici B.; Ozgenc F.; Kalayci A.G.; Targan S.; Ozkan T.; Selimoglu A.; Doganci T.; Kansu A.; Tosun S.; Arslan N.; Kasirga E.; Bosnak M.; Haspolat K.; Buyukgebiz B.; Aydogdu S.; Girgin N.; Yagci R.V.
    Background and Aim: The aim of the present study was to compare the therapeutic efficacy of three different regimens in childhood chronic hepatitis B (CHB) infection. Methods: A total of 182 children with CHB infection were prospectively allocated to three random groups. Sixty-two patients in the first group received high-dose interferon (IFN)-α 2b (10 MU/m2) thrice/weekly alone for 6 months. In the second (n = 60) and third groups (n = 60), IFN-α was used for 6 months (5 MU/m2) thrice/weekly in combination with lamivudine (LAM) (4 mg/kg, maximum 100 mg/day) for 12 months. Lamivudine was started simultaneously with IFN in the second group, while it was started 2 months prior to IFN injections in the third group. Results: The initial mean alanine aminotransferase (ALT) values for the first, second and third groups were 109 ± 93 IU/L, 101 ± 64 IU/L and 92 ± 42 IU/L, respectively (P > 0.05). At the end of the therapy, ALT values decreased to 82 ± 111 IU/L, 38 ± 41 IU/L and 29 ± 16 IU/L in groups 1, 2 and 3, respectively. The mean ALT value of the first group was significantly different to the second and third groups (P = 0.046 and P = 0.002, respectively) at the end of the therapy and these differences were found to be sustained after 18 months. However, results in the second and third groups were similar (P > 0.05). There were no significant differences in HBeAg clearance and anti-HBe seroconversion at the initial stage, 12 months and 18 months between the three groups (P > 0.05). Hepatitis B virus (HBV) DNA clearance in the first group was different from the second and third groups, while the second and third groups had similar HBV DNA clearance ratios at 12 and 18 months. No significant difference was found in the complete response (normalization of ALT, clearance of HBV DNA and seroconversion of anti HBe) ratios of all groups (at 12 months: 28.8, 45.5, 35.8% and at 18 months 33.3, 49 and 34% in groups 1, 2 and 3, respectively, P > 0.05). Conclusions: Although the ALT normalization and HBV DNA clearance ratios of IFN plus LAM combination groups were better than the high-dose IFN-α monotherapy group, no significant difference was found in the complete response ratios of all three groups. © 2004 Blackwell Publishing Asia Pty Ltd.
  • No Thumbnail Available
    Item
    Compression after low velocity impact tests of marine sandwich composites: Effect of intermediate wooden layers
    (Elsevier Ltd, 2018) Balıkoğlu F.; Demircioğlu T.K.; İnal O.; Arslan N.; Ataş A.
    In the present work, compression after impact (CAI) behavior of sandwich composite materials with intermediate wooden layers was investigated. Sandwich panels were manufactured by using vacuum assisted resin transfer molding (VARTM) method with pinewood and ashwood intermediate layers. 15 and 25 mm thick PVC foams with a same density of 80 kg/m3 were chosen in conjunction with the face sheets composed of non-crimp biaxial E-glass fabrics and bisphenol-A epoxy vinyl ester resin material system. Impact tests were performed under 30 J (low) and 60 J (high) energy levels with conical and hemispherical impactors. CAI tests were conducted in accordance with the ASTMC364/C364M-07 standard. Using pinewood and ashwood intermediate layers increased the residual CAI strength and decreased the depth of the impact damage. The intermediate wooden layers have also a potential to reduce the thickness of the composite face sheets and foam core which may increase the proportion of the recyclable wooden materials within the sandwich structure. © 2017 Elsevier Ltd
  • No Thumbnail Available
    Item
    Experimental investigation on low-velocity impact response of wood skinned sandwich composites with different core configurations
    (Elsevier Ltd, 2018) Demircioğlu T.K.; Balıkoğlu F.; İnal O.; Arslan N.; Ay İ.; Ataş A.
    In this paper, an experimental investigation on the low-velocity impact response of wood skinned hybrid sandwich composites was presented. Several alternative design configurations were developed by using rubber-cork and E-glass composite layers between the foam core and wood skin in order to improve the impact performance of conventional sandwich composites. Low-velocity impact (LVI) testing was performed using a drop weight test machine at different impact energies and destructive cross-sectioning was performed to examine the interior damage growth and penetration depth of the specimens. The impact performance of the specimens was evaluated in terms of energy absorption capacity, maximum contact force and penetration depth. The multi-core design concept significantly improved the energy absorption capacity with a reduced extent of impact induced damage. The proportion of recyclable materials in each configuration and the energy absorption level per unit cost were also presented for the interest of product designers. © 2018 Elsevier Ltd
  • No Thumbnail Available
    Item
    Mechanical performance of marine sandwich composites subjected to flatwise compression and flexural loading: Effect of resin pins
    (SAGE Publications Ltd, 2020) Balıkoğlu F.; Demircioğlu T.K.; Yıldız M.; Arslan N.; Ataş A.
    Mechanical performance of marine sandwich panels comprising E-glass/vinyl ester face sheets and perforated poly-vinyl chloride foam core was evaluated and compared with conventional foam core sandwich panels. Circular holes through the foam core thickness were drilled with 12 different arrangements in square patterns and the holes were filled with the resin during the infusion process which created the through-the-thickness solid resin pins. The effect of each pattern on the flatwise compression and core shear properties of the sandwich panels were experimentally investigated. The three-point bending maximum failure load of perforated foam core sandwich panels was increased over 133.8% by increasing the diameter of the resin pins at the expense of increased panel weight up to 67%. The flatwise compression stress to induce core crushing was significantly increased by reinforcing the resin pins. © The Author(s) 2018.
  • No Thumbnail Available
    Item
    Improving four-point bending performance of marine composite sandwich beams by core modification
    (SAGE Publications Ltd, 2020) Balıkoğlu F.; Arslan N.; Demircioğlu T.K.; İnal O.; İren M.; Ataş A.
    The aim of this study was to improve four-point bending performance of foam core sandwich composite beams by applying various core machining configurations. Sandwich composites have been manufactured using perforated and grooved foam cores by vacuum-assisted resin transfer moulding method with vinyl-ester resin system. The influence of grooves and perforations on the mechanical performance of marine sandwich composite beams was investigated under four-point bending test considering the weight gain. Bending strength and effective bending stiffness increased up to 34% and 61%, respectively, in comparison to a control beam without core modification. Analytical equations were utilised for calculating the mid-span deflection, equivalent bending stiffness and ultimate bending strength of the sandwich beams. Finite element analysis was also performed to analyse the flexural response of the specimens taking into account the combined effect of orthotropic linear elasticity of the face sheet and the non-linear behaviour of the foam core. © The Author(s) 2020.
  • No Thumbnail Available
    Item
    Familial mediterranean fever mutation analysis in pediatric patients with İnflammatory Bowel Disease: A multicenter study
    (AVES, 2021) Urganci N.; Ozgenc F.; Kuloǧlu Z.; Yüksekkaya H.; Sari S.; Erkan T.; Önal Z.; Çaltepe G.; Akçam M.; Arslan D.; Arslan N.; Artan R.; Aydoǧan A.; Balamtekin N.; Baran M.; Baysoy G.; Çakir M.; Dalgiç B.; Doǧan Y.; Durmaz O.; Ecevit C.; Eren M.; Gökçe S.; Gülerman F.; Gürakan F.; Hizli S.; Işik I.; Kalayci A.G.; Kansu A.; Kutlu T.; Karabiber H.; Kasirga E.; Kutluk G.; Hoşnut F.O.; Özen H.; Özkan T.; Öztürk Y.; Soylu O.B.; Tutar E.; Tümgör G.; Ünal F.; Ugraş M.; Üstündaǧ G.; Yaman A.
    Background: The aim of the study was to evaluate familial Mediterranean fever (FMF) mutation analysis in pediatric patients with inflammatory bowel disease (IBD). The relation between MEFV mutations and chronic inflammatory diseases has been reported previously. Methods: Children with IBD (334 ulcerative colitis (UC), 224 Crohn's disease (CD), 39 indeterminate colitis (IC)) were tested for FMF mutations in this multicenter study. The distribution of mutations according to disease type, histopathological findings, and disease activity indexes was determined. Results: A total of 597 children (mean age: 10.8 ± 4.6 years, M/F: 1.05) with IBD were included in the study. In this study, 41.9% of the patients had FMF mutations. E148Q was the most common mutation in UC and CD, and M694V in IC (30.5%, 34.5%, 47.1%, respectively). There was a significant difference in terms of endoscopic and histopathological findings according to mutation types (homozygous/ heterozygous) in patients with UC (P < .05). There was a statistically significant difference between colonoscopy findings in patients with or without mutations (P = .031, P = .045, respectively). The patients with UC who had mutations had lower Pediatric Ulcerative Colitis Activity Index (PUCAI) scores than the patients without mutations (P = .007). Conclusion: Although FMF mutations are unrelated to CD patients, but observed in UC patients with low PUCAI scores, it was established that mutations do not have a high impact on inflammatory response and clinical outcome of the disease. Copyright © 2021 by The Turkish Society of Gastroenterology.
  • No Thumbnail Available
    Item
    Comparison of Four Different DNA Isolation Methods from MGIT Culture for Long-Read Whole Genome Sequencing of Mycobacterium tuberculosis
    (Brieflands, 2024) Arslan N.; Demiray-Gurbuz E.; Ozkutuk N.; Esen N.; Özkütük A.A.
    Background: Tuberculosis (TB) remains a global health challenge, particularly due to drug resistance and limitations in rapid diagnosis. Next-generation sequencing (NGS), especially long-read whole genome sequencing (WGS), shows promise for rapidly detecting TB and drug resistance, but it requires high-quality DNA, which is difficult to extract from Mycobacterium tuberculosis due to its complex cell wall. Objectives: This study evaluated four DNA isolation methods for extracting pure DNA from M. tuberculosis, aiming to standardize protocols for long-read WGS. Methods:Mycobacterium tuberculosis H37RV colonies were grown in BACTEC MGIT liquid medium. Two pellets were prepared as the initial material for the DNA extraction protocol: Pellets from 1 mL McFarland 2 suspensions and all growing colonies from two MGIT liquid cultures. Four DNA extraction methods were used: The cetyltrimethylammonium bromide (CTAB) method, GeneJET Genomic DNA Purification Kit, Quick-DNA Fecal/Soil Microbe Kit, and Genematrix Tissue/Bacterial DNA Purification Kit, with some modifications. DNA quality was assessed based on concentration, purity, and integrity. Results: Among the tested methods, the Quick-DNA Fecal/Soil Kit yielded approximately 85 ng/mL of DNA and a purity of 1.9 at 260/280 nm from the colonial pellet of two MGIT tubes. However, lower intact DNA [DNA integrity number (DIN) ~ 6.8] was obtained with this kit. The CTAB method provided the highest intact DNA (DIN ~ 9.5), although the purity of the DNA was not sufficient. Conclusions: Based on three repetitions of McF-2 and colonial pellet extractions, the Quick-DNA Fecal/Soil Kit yielded the highest DNA quantity and purity but showed lower integrity compared to other methods, indicating the need for adjustments. A pellet from two MGIT cultures (~ 100 µL) is suitable for long-read WGS with this kit. However, a larger sample size is required to generalize these findings. For effective long-read sequencing of M. tuberculosis, DNA extraction protocols must be optimized to balance yield, fragment size, and purity for accurate sequencing and drug resistance analysis. © 2024, Arslan et al.
  • No Thumbnail Available
    Item
    Fabry disease in familial Mediterranean fever according to the severity of the disease; [Enfermedad de Fabry en la fiebre mediterránea familiar según la gravedad de la enfermedad]
    (Ediciones Doyma, S.L., 2024) Uslu S.; Kabadayi G.; Teke Kısa P.; Yüce Inel T.; Arslan Z.; Arslan N.; Akar S.; Onen F.; Sari I.
    Objectives: Mutations in the α-galactosidase A (GLA) gene result in Fabry disease (FD), a rare metabolic condition. FD patients present with heterogeneous clinical manifestations, which may overlap with systemic diseases including familial Mediterranean fever (FMF). The aim of this study was to determine the frequency of FD in patients with mild and severe FMF and to prevent misdiagnosis by increasing clinicians’ awareness. Methods: Based on Tel-Hashomer criteria, the study included a total of 91 FMF patients. Patients were divided into two groups according to the number of recurrent clinical episodes or failure to respond to maximum therapy: those with mild and severe forms of the disease. GLA gene mutations and α-GLA enzyme activity were assessed. Records of MEFV mutations, therapies and demographic characteristics were kept. Results: FD testing was performed on a cohort of 91 FMF patients, 54.9% had mild FMF, 45.1% had severe FMF, and only one patient in the mild FMF subgroup tested positive for FD. The patient was a 39-year-old woman with a history of recurrent abdominal pain, distal limb pain and fever. She had low GLA enzyme activity and a heterozygous GLA gene mutation. Conclusions: Our findings suggest that FD should be considered in the differential diagnosis of FMF, especially in individuals with unusual symptoms. © 2024 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología