298 research outputs found
A morphological and phenological comparison of chestnut (Castanea) cultivars 'Serdar' and 'Marigoule'
No full textMorphological and phenological characteristics of the chestnut (Castanea sativa Mill.) cultivar (cv) 'Serdar' were examined and compared to the cv 'Marigoule', a European x Japanese (C. sativa x C. crenata) hybrid. Morphological characteristics such as tree vigor and growth habit, shoot, leaf, flower, bur and fruit characteristics and phenological characteristics such as time of bud break, flowering, nut ripening and leaf fall were studied. Three trees per genotype and 10-50 samples per tree were examined for each quantitative characteristic. Cultivar 'Serdar' was represented by vigorous trees with semi-upright growth similar to cv 'Marigoule'. Shoots of 'Serdar' were thinner and the shoot bark was browner than 'Marigoule'. 'Serdar' had a higher lenticel density than 'Marigoule' and 'Serdar' had relatively short internodes similar to 'Marigoule'. 'Serdar' initiated break bud 11 days later than 'Marigoule', bloomed 1-2 days later than 'Marigoule', and nuts ripened 20 days later than nuts from 'Marigoule'. Leaf fall of cv 'Serdar' was one day earlier than cv 'Marigoule'. The lamina, petioles and leaves of the 'Serdar' were longer than those of 'Marigoule'; however, 'Serdar' had a lower ratio of lamina width/lamina length and lamina width/leaf length. 'Serdar' and 'Marigoule' were placed in the same group with respect to all flower characteristics investigated. 'Serdar' had globular burs with long spines. Its density of spine was also higher than 'Marigoule'. 'Serdar' had very bright, reddish brown coloured shells, with light cream coloured kernels; and, the fruit had good flavor. Peeling of the seed coat of 'Serdar' was easier than that of 'Marigoule'. The fruit of 'Serdar' was smaller than those of 'Marigoule' and the relative size of the hilum in relation to the upper part of fruit was intermediate in 'Serdar' and large in 'Marigoule'. 'Serdar' showed a higher propensity for splitting of the pericarp although both cultivars were placed within the same group. The cv 'Serdar' can be recommended for new chestnut orchards due to some of its positive advantages such as earlier bearing, blooming twice in a single growing season, resistance to spring frosts and its low susceptibility to chestnut blight
Dentinal tubule occluding capability of nano-hydroxyapatite; The in-vitro evaluation
No full textTurkoz, Mustafa Burak/0000-0002-4127-7650; dogan, mustafa/0000-0002-3782-8640; Dogan, Mustafa/0000-0002-4437-566X; Erdem, Umit/0000-0002-0480-8176In this in-vitro study, the effectiveness of experimental pure nano-hydroxyapatite (nHAP) and 1%, 2%, and 3% F doped nano-HAp on dentine tubule occlusion was investigated. And also, the cytotoxicity of materials used in the experiment was evaluated. Nano-HAp types were synthesized by the precipitation method. Forty dentin specimens were randomly divided into five groups of; 1no treatment (control), 2specimens treated with 10% pure nano-HAp and 3, 4, 5 specimens treated with 1%, 2%, and 3% F(-)doped 10% nano-HAp, respectively. To evaluate the effectiveness of the materials used; pH, FTIR, and scanning electron microscopy evaluations were performed before and after degredation in simulated body fluid. To determine cytotoxicity of the materials, MTT assay was performed. Statistical evaluations were performed with F and t tests. All of the nano-HAp materials used in this study built up an effective covering layer on the dentin surfaces even with plugs in tubules. It was found that this layer had also a resistance to degradation. None of the evaluated nano-HAp types were have toxicity. Fluoride doping showed a positive effect on physical and chemical stability until a critical value of 1% F-. The all evaluated nano-HAp types may be effectively used in dentin hypersensitivity treatment. The formed nano-HAp layers were seem to resistant to hydrolic deletion. The pure and 1% F(-)doped nano-HAp showed the highest biocompatibility thus it was assessed that pure and 1% F(-)doped materials may be used as an active ingredient in dentin hypersensitivity agents
Growth rate of a giant Tarlov (perineural) cyst with intrapelvic extension
No full textMalcok, Umit Ali/0000-0002-1272-9654Background and importanceGiant Tarlov cysts (GTCs) are perineural cysts and their presacral intrapelvic extension are extremely rare entities. We present a case of GTC with intrapelvic extension who has preoperative Magnetic Resonance Imaging (MRI) follow-ups of 12 years, and we demonstrate the annual growth rate and the time-size correlation of a GTC.MethodsCase report.Clinical presentationA 37-year-old woman was admitted with left gluteal pain radiating to left foot, left leg numbness, progressed over 12 years. On MRI, starting from the L5-S1 level, a giant Tarlov cyst with an atypical configuration, is observed. The patient had a known sacral Tarlov cyst, first discovered on MRI obtained 12 years before the surgery. She had 6 consecutive MRI follow-ups in 12 years preoperatively. The cysts diameters have been measured and the growth rate was estimated. We showed for the first time that presented GTC grows in in both Sagittal Diagonal (SD) and Sagittal Craniocaudal (SC) diameters over time with overall annual growth rates, 7.671% for RGR_SD and 6.237% for RGR_SC.ConclusionWhen the time-size correlation is observed, it becomes evident that the GTSs' growing speed increases over the years because of minimal resistance in the intrapelvic cavity. Early surgery may be considered to prevent rapid growth in the intrapelvic cavity and to reduce possible complications of the giant cyst.Scientific and Techno-logical Research Council of Turkiye (TUBIdot;TAK)Open access funding provided by the Scientific and Techno-logical Research Council of Turkiye (TUB & Idot;TAK).Science Citation Index Expande
On Unfair Permutations
No full textIslak, Umit/0000-0003-4281-5171In this paper we study the inverse of so-called unfair permutations. Our investigation begins with comparing this class of permutations with uniformly random permutations, and showing that they behave very much alike in case of locally dependent random variables. As an example of a globally dependent statistic we use the number of inversions, and show that this statistic satisfies a central limit theorem after proper centering and scaling. (C) 2018 Elsevier B.V. All rights reserved.TUBITAK [113F059]; Scientific and Research Council of Turkey [TUBITAK-117C047]The author C. P. has been supported by TUBITAK within the project 113F059 entitled "The conjecture of Mazur-Tate-Teitelbaum, CM elliptic curves and applications" as a postdoctoral researcher at Koc University. The author U.I. is supported by the Scientific and Research Council of Turkey [TUBITAK-117C047]. Parts of this paper were completed at the Nesin Mathematics Village, the authors would like to thank Nesin Mathematics Village for their kind hospitality. Also, the authors would like to thank an anonymous referee who detected some errors in original manuscript, and whose comments improved the paper significantly
Ten-year outcome of chronic thromboembolic pulmonary hypertension patients in a tertiary center
No full textObjective: Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the leading causes of pulmonary hypertension (PH). We aimed to investigate the outcome of CTEPH patients who were followed-up by a PH outpatient clinic. Methods: We screened the medical records of 29 PH patients who were followed-up by a PH outpatient clinic between 2009 and 2018. The patients' demographics and their clinical, echocardiographic, and hemodynamic characteristics were recorded. Results: Our study group consisted of 16 females (55.2%) and 13 males (44.8%). The mean age was 59.5 +/- 13.7 years and the median follow-up duration was 44 months (1-113 months). The mean initial 6-minute walking distance (6MWD) was 321.4 +/- 119.9 m. The initial median N-terminal pro brain natriuretic peptide (NT-proBNP) level was 2468 pg/mL (46.1-20.564 pg/mL). All patients were on oral anticoagulant therapy. Pulmonary endarterectomy (PEA) was performed in 17 of 29 patients (58.6%). Twelve patients (41.4%) were not operated upon due to distal disease, comorbidities, or their own preference. The operated patients were younger than the non-operated patients (55 years & 65 years, p=0.04). At the follow-up, the 6MWD in the operated patients increased (+76 m) and decreased in non-operated patients (-46 m). The survival rate at 10-year follow-up was 58.6% for the whole group. Twelve patients died during the follow-up period. While 7 of 12 not-operated patients died (58.3%), just 5 of 17 operated patients (4 perioperatively and 1 at follow-up) died (29%). Advanced-stage final functional capacity (FC) [New York Heart Association (NYHA) III-IV], inoperability, lower final 6MWD, higher final NT-proBNP, and reduced tricuspid annular plane systolic excursion (TAPSE) were associated with an increased mortality rate. Univariate Cox regression analysis showed that patients with NYHA I-II final FC showed a 166-fold decreased mortality rate. Conclusion: The long-term prognosis of operated patients is better than the outcome of not-operated patients. The strongest predictor associated with mortality was a worse final FC (NYHA III-IV)
pollen germination and tube growth of some European chestnut genotypes (
No full textIntroduction. Investigation of pollen performance is essential in breeding experiments or artificial pollination procedures, especially in a crop such as chestnut, some genotypes of which are characterized by male sterility. Our study was carried out to determine the pollen germination rate and the pollen tube growth of some European chestnut genotypes. Materials and methods. Seven Turkish advanced chestnut selections (SE3-12, SE18-2, SE21-2, SE21-9, 552-8, 552-10 and 554-14), and a cultivar (Sariaslama), growing in two different locations, were studied in the central Black Sea region of Turkey in 2006. For this purpose, in vitro pollen germination tests were performed on media with four different concentrations of sucrose [(0, 5, 10 and 15)%]. Results and discussion. The pollen germination rates of the eight genotypes studied were significantly different due to the sucrose concentrations. The best pollen germination rate was found in the 554-14 chestnut genotype (35.80%). The best sucrose concentration for a high germination rate and pollen tube growth was 10%. For the same genotype, the results varied due to the two different study locations (Terme and Fatsa). A linear relationship between the sucrose concentrations and pollen tube length was found to be significant in most genotypes. The longest pollen tube length was found in the 554-14 genotype (74 mm)
Low-cost, highly efficient, and tunable ultrafast laser technology based on directly diode-pumped Cr:Colquiriites
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 335-352).This doctoral project aims to develop robust, ultra low-cost (150) as the pump source, we have obtained continuous-wave (cw) output powers >250-mW with slope efficiencies >50%. Record cw tuning ranges were demonstrated for Cr:LiSAF (775-1042 nm), Cr:LiSGaF (777-977 nm), and Cr:LiCAF (754-871 nm). For femtosecond pulse generation, semiconductor saturable absorber mirrors (SESAMs/SBRs) were developed, which were used to initiate and sustain mode-locking. Typical performance was ~25-100 fs pulses, with an optical spectrum in the 770-920 nm range, with ~1-2 nJ of pulse energies from ~100-MHz repetition rate cavities. Record electrical-to-optical conversion efficiencies of ~10% were demonstrated in the cw mode-locked regime. A mode-locked tuning range of 767-817 nm, with ~130-fs long pulses was obtained by using Cr:LiCAF as gain medium. With the Cr:LiSAF gain medium, using regular SESAMs/SBRs centered around 800 nm, 850 nm, and 910 nm, mode-locked tuning ranges of 803-831 nm, 828-873 nm, and 890-923 nm were demonstrated, respectively. By using a broadband oxidized SESAM/SBR, a record tuning range of 800-905 nm was demonstrated with ~150-fs long pulses. Using an extended cavity Cr:LiCAF laser, pulse energies >15-nJ with peak powers exceeding 100-kW were obtained. We performed the first cavity-dumping experiments with a Cr:Colquiriite laser and demonstrated pulse energies >100-nJ, and peak powers approaching MW level, at repetition rates up to 50-kHz. Cr:LiCAF gain media were also pumped by single-emitter multimode diodes, where we obtained >2-W output power in cw operation, and ~100-fs pulses with 390-mW of average power at a repetition rate of 140 MHz in cw mode-locked operation. As an example application area for this low cost technology, we performed multiphoton microcopy experiments with a single-mode diode-pumped Cr:LiCAF laser. We also performed attosecond-resolution timing jitter characterization experiments of the femtosecond Cr:LiSAF laser, and measured a record-low upper limit for the integrated timing jitter of the Cr:LiSAF laser (137-attoseconds in 10 kHz-10 MHz range).by Umit Demirbas.Ph.D
Broadly tunable two-color lasing of Cr:LiCAF with on-surface and off-surface optical axis birefringent filters: performance comparison
No full textWe studied the two-color lasing performance of a Cr:LiCAF laser using crystal quartz on-surface and off-surface optical axis birefringent filters (BRFs). Four different on-surface optical axis BRFs with thicknesses of 2 mm, 4 mm, 8 mm, and 16 mm, and three different off-surface optical axis BRFs with a diving angle of 25° and thicknesses of 2 mm, 4 mm, and 8 mm have been tested. Two-color lasing operation could be achieved in tens of different pairs of wavelengths using both types of BRFs. Regular on-surface optical axis BRFs provided two-color lasing in the 772–810 nm interval, with a discretely tunable wavelength separation of 1 to 37 nm (0.5 to 17 THz). In comparison, the off-surface optical axis BRFs enabled scanning of two-color lasing spectra in a much broader wavelength range between 745 nm and 850 nm with a discretely tunable wavelength separation of 0.8 to 99 nm (0.4 to 46 THz). The results clearly demonstrate the advantages of using off-surface optical axis BRFs to achieve two-color lasing with broadly tunable wavelength separation
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