212 research outputs found
Static and dynamic properties of CN/Cu(001) surfaces and oxidation, dissociation and bimolecular debarboxylation of isocyanate species adsorbed on Cu(001)
No full textThis dissertation presents an outlines my investigations of static and dynamic properties of adsorbed cyanide (CN) and isocyanate (-NCO) species as well as some of their chemistries. Surface bound CN-containing species have not previously been studied extensively, partially due to the inapplicability of fundamental e-beam based surface analysis techniques for investigations. I had the opportunity in my studies to employ multiple surface probing techniques, i.e. HAS, XPS, NEXAFS, TPD and RAIRS, to compile and cross-examine information from CN, –NCO, and derived species, adsorbed on the Cu(001) surface. While angle resolved He atom scattering (HAS) was employed to identify and investigate the ordered superstructure of CN/Cu(001) surfaces, TOF-HAS was employed to investigate its dynamic properties. The CN/Cu(001) surface induced unprecedented simultaneous coherent He diffraction with a large “classical” multiphonon backscattered He intensity. A superstructure is implied that contains both rigidly bound CN species, which maintain the long range c(10x6) translational symmetry, together with bound highly-dynamic CN species that exhibit large thermally induced displacements. The NEXAFS measurements suggest multiple spatial binding configurations for the adsorbed CN moieties. In addition, TPD spectra of C2N2 desorption from CN/Cu(001) surface were analyzed, using my newly developed method, to determine the activation energies for desorption as a function of CN coverage. There are two reactions of NCO species examined in my studies. The first is the newly discovered mutual reaction between NCO species. This type of interaction had not been seen before, as it is essentially difficult to prepare pure NCO/metallic surfaces. Copper was chosen as a substrate as HNCO exposures of Cu(001) at RT, followed by spontaneous H2 desorption, do produce NCO only surfaces. A thermal treatment of the surface, at 573K, leads to a bimolecular decarboxylation of NCO, leaving a carbodimide species (NCN) on the surface. The sp-hybridized linear NCN moieties, which are bound nearly parallel to the substrate, show high thermal stability. The second reaction of NCO, which I have studied, is its oxidation. In particular, the effect of CN coadsorbates on the oxidation of NCO was studied. It was found that the presence of CN catalyzes a dissociation reaction of NCO species on Cu(001).Ph. D.Includes bibliographical referencesby Erkan Ziya Ciftlikl
Comparison of the accuracy and reliability of the AmniSure, AMNIOQUICK, and AL-SENSE tests for early diagnosis of premature rupture of membranes
No full textObjective To compare the accuracy and reliability of the AmniSure, AMNIOQUICK, and AL-SENSE tests with conventional tests to diagnose suspected premature rupture of membranes (PROM). Methods A prospective cohort study of 60 pregnant women at 25-36 weeks of pregnancy with suspected PROM was conducted between January and April 2015. AmniSure (Qiagen Sciences LLC, Germantown, MD, USA), AMNIOQUICK (BIOSYNEX, Strasbourg, France), and AL-SENSE (Common Sense Ltd, Caesarea, Israel) tests were performed after conventional tests (ultrasonography, pooling, nitrazine, and fern tests) and women were followed-up for 7 days. Sensitivity, specificity, and diagnostic accuracy, among others, were assessed and compared. Results For women with a confirmed diagnosis of PROM, the sensitivity and specificity of conventional tests were 93.7% and 100.0%, respectively; diagnostic accuracy was 98.3%. Sensitivity, specificity, and diagnostic accuracy were all 100.0% for AmniSure. Sensitivity, specificity, and diagnostic accuracy for AMNIOQUICK were 75.0%, 97.7%, and 91.6%, respectively. Sensitivity, specificity, and diagnostic accuracy were 75.0%, 86.3%, 83.3%, respectively, for the AL-SENSE pad test. Conclusion The AmniSure test was most sensitive and specific for diagnosing PROM compared with the other tests and is reliable and usable
Effect of size and slenderness on the axial-compressive behavior of basalt FRP-confined predamaged concrete
No full textTo investigate the size and slenderness effect on the axial-compressive behavior of basalt fiber-reinforced polymer (BFRP)-confined predamaged concrete, five groups of concrete cylinders with different sizes and slenderness ratios were designed and tested. The cylinders were axially preloaded to three predamage levels, then repaired using BFRP, and reloaded. The results showed that the concrete predamage had an adverse effect on the ultimate strength and initial elastic modulus of BFRP-confined concrete. Except for the smallest specimens affected by the wall effect, the initial analysis found that the ultimate strength of BFRP-confined concrete decreased with an increase in size and slenderness ratio, and the size and slenderness effect decreased with an increase in BFRP confining pressure, while these increased with the severity of concrete predamage. However, there was no obvious size or slenderness effect on the ultimate strain of BFRP-confined concrete. Through multifactorial analysis, it was confirmed that the ultimate strength of BFRP-confined undamaged and predamaged concrete was influenced by the slenderness. Considering the effect of size, slenderness, and predamage, monotonic and cyclic models were developed for BFRP-confined concrete. Finally, a uniaxial material object was added into OpenSees to provide an effective numerical material model for theoretical analyses and engineering applications. © 2021 American Society of Civil Engineers.The present research was supported by the National Natural Science Foundation of China (Grant No. 51878268) and the Natural Science Foundation of Hunan Province, China (Grant No. 2020JJ4195).
Part of this research was completed by the first author in collaboration with the third and fourth authors during his one-year visit to Ohio State University. The first author acknowledges the State Scholarship Fund of China Scholarship Council (Grant No. 201606135057) for supporting this work and his research visit to the United States
Comparison of neuroprotective effects of isoflurane and sevoflurane on cerebral ischemia
No full textÇalışmamızda, intrakranial tümör cerrahisi geçirecek hastalarda, isofluran ve sevofluranın eşdeğer konsantrasyonlarda uygulayarak serebral iskemi üzerine olan etkilerini, serum S-100B protein ölçerek değerlendirmeği amaçladık. Gereç ve Yöntem: Etik kurul onayı alındıktan sonra ASA I-III grubu, intrakranial tümör cerrahisi nedeniyle elektif şartlarda opere edilecek 20 hasta rastgele iki gruba ayrıldı. Anestezi indüksiyonu sodyum tiyopental , fentanil ve vekuronyum ile sağlandı. İdamede %50 oksijen-hava karışımı içinde %0,8-1,2 minimum alveolar konsantrasyonda isofluran veya sevofluran verildi. Kalp atım hızı, sistolik arter basıncı, diyastolik arter basıncı, ortalama arter basıncı, periferik oksijen satürasyonu, santral venöz basınç ve end-tidal karbondioksit değerleri oprerasyon süresince ölçüldü. S-100B protein değerlerinin takibi için ise 9 ayrı zamanda periferik kan örneği alındı. Gruplar arası karşılaştırmada demografik veriler ve diğer veriler için mann-Whitney U testi kullanıldı. Verilerin grup içi karşılaştırılmasında wilcoxon sıra toplamları testi uygulandı. Bulgular: Olguların demografik verileri ve operasyon süreleri benzer olarak bulundu. Çalışma grupları karşılaştırıldığında kalp atım hızı, sistolik arter basıncı, ortalama arter basıncı ve end-tidal karbondioksit' deki değişiklikler benzer olarak saptanırken, diyastolik arter basıncı' n da sadece entübasyon sonrasında isofluran grubunda düşme, sevofluran grubunda ise yükselme görüldü (p<0,05). Grup içi ve gruplar arası karşılaştırmada her iki grupta da santral venöz basınç ve periferik oksijen satürasyonu değerlerinde anlamlı fark saptanmadı. Gruplar arası karşılaştırmada her iki grupta da S-100B protein ölçüm ortalamalarında anlamlı fark saptanmadı. Sonuç: İntrakranial tümör cerrahisi sırasında nöroanestezide tercih edilen volatil anestezik ajanlardan isofluranın ile sevofluranın serebral iskemi üzerine benzer nöron koruyucu etkiler meydana getirdiğini ve sevofluranın isoflurana iyi bir alternatif olabileceği sonucuna varıldı.In this study, we aimed to evaluate the effects of isoflurane and sevoflurane on cerebral ischemia in patients undergoing intracranial tumour surgery by measuring serum S-100B protein. Material and Method: After the approval of the ethics committee, 20 ASA I-III group patients, who were to be operated in elective conditions due to intracranial tumour surgery, were randomly assigned to two groups. Anaesthesia induction was performed with thiopental, fentanyl and vecuronium. In the maintenance, isoflurane or sevoflurane was administered in a 50% oxygen-air mixture at a minimum alveolar concentration of 0.8-1.2%. Heart rate, systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, peripheral oxygen saturation, central venous pressure and end-tidal carbon dioxide values were measured during the operation. For monitoring S-100B protein values, peripheral blood samples were taken at 9 separate times. The Mann-Whitney U test was used for statistical analysis. Wilcoxon rank sums test was applied in intra-group comparisons of the data. Findings: Demographic data and operative times were found to be similar for the cases. Heart rate, systolic arterial pressure, mean arterial pressure and the deviations in the end-tidal carbon dioxide were similar in the study groups, whereas diastolic arterial pressure was found to be significantly higher in isoflurane group after the intubation, and there was an increase in the sevoflurane group (p<0.05). Intra-group and intergroup comparisons revealed no significant difference in central venous pressure and peripheral oxygen saturation values in both groups. There was no significant difference in S-100B protein measurements in both groups in the comparison between groups. Conclusion: It was concluded that isoflurane and sevoflurane, which are among the preferred volatile anaesthetic agents in neuro-anaesthetics during intracranial tumour surgery, have similar neuron protective effects to cerebral ischemia and sevoflurane may be a good alternative to isoflurane
The comparison of the neuroprotective effects of isoflurane and sevoflurane on cerebral ischemia
No full textAmaç: Çalışmamızda, intrakranial tümör cerrahisi geçirecek hastalarda, genel anestezi idamesinde sık kullanılan isofluran ile sevofluranın serebral iskemi üzerine olan etkilerini, iskeminin önemli bir göstergesi olan S-100B protein değerlerini ölçerek, karşılaştırmayı amaçladık. Gereç ve Yöntem: Etik kurul onayı alındıktan sonra ASA l-lll grubu, intrakranial tümör cerrahisi nedeniyle efektif şartlarda opere edilecek 20 hasta rasgele iki gruba ayrıldı. İndüksiyon öncesinde midazolam ve lidokain uygulanan hastaların anestezi indüksiyonu sodyum tiyopental, fentanil ve vekuronyum ile sağlandı. İdamede %50 oksijen-hava karışımı içinde %0,8-1,2 minumum alveolar konsantrasyonda isofluran veya sevofluran verildi. Kalp atım hızı, sistolik arter basıncı, diyastolik arter basıncı, ortalama arter basıncı, periferik oksijen satürasyonu, santral venöz basınç ve end-tidal karbondioksit değerleri operasyon süresince ölçüldü. S-100B protein değerlerinin takibi için ise operasyon öncesi dönemden itibaren, operasyon sırasında ve operasyon sonrası dönemde olmak üzere 9 ayrı zamanda periferik kan örneği alındı. Gruplar arası karşılaştırmada demografik veriler ve diğer veriler için Mann-VVhitney U testi kullanıldı. Verilerin grup içi karşılaştırılmasında Wilcoxon sıra toplamları testi uygulandı. Bulgular: Olguların demografik verileri ve operasyon süreleri benzer olarak bulundu. Çalışma grupları karşılaştırıldığında kalp atım hızı, sistolik arter basıncı, ortalama arter basıncı ve end-tidal karbondioksit' deki değişiklikler benzer olarak saptanırken, diyastolik arter basıncı' nda sadece entübasyon sonrasında isofluran grubunda düşme, sevofluran grubunda ise yükselme görüldü (p[0,05). Grup içi ve gruplar arası karşılaştırmada her iki grupta da santral venöz basınç ve periferik oksijen satürasyonu değerlerinde anlamlı fark saptanmadı. Gruplar arası karşılaştırmada her iki grupta da S- 100B protein ölçüm ortalamalarında anlamlı fark saptanmadı. Sonuç: İntrakranial tümör cerrahisi sırasında nöroanestezide tercih edilen volatil anestezik ajanlardan isofluran ile sevofluranın serebral iskemi üzerine benzer nöron koruyucu etkiler meydana getirdiği ve sevofluranın isoflurana alternatif olarak kullanılabileceği sonucuna varıldı.The Aim of Investigation: The aim of this study was to compare the effects of frequently used volatile agent isoflurane with sevoflurane in equipotent anesthetic concentrations on cerebral ischemia with measuring S-1008 protein values that are indicated ischemia in patients undergoing intracranial tumor surgery. Material and Methods: After obtaining the ethical committee approval, ASA grade 1-111, 20 patients scheduled for intracranial tumor surgery, were assigned randomly into two groups. Before induction, midazolam and lidocain were applied and induction was performed with sodium thiopental, fentanyl and vecuronium. Anesthesia was maintained with %0,8-1,2 minimum alveolar concentration, end tidal concentration of isoflurane or sevoflurane in % 50 air in oxygen. Heart rate, systolic, diastolic and mean arterial pressures, peripheral oxygen saturation, central venous pressure and end tidal concentration of carbon dioxide were measured during surgery. For S-1008 protein values, peripheral blood samples were taken at nine different times, including before surgery, during surgery and the end of surgery. Mann-Whitney U and Wilcoxon signed rank test were used for statistical analysis. Results: The demographic data and operation times were comparable in both group. The changes in heart rate, systolic arterial pressure, mean arterial pressure and end tidal concentration of carbon dioxide were similar but only after intubation diastolic arterial pressure was decreased in isoflurane group, increased in sevoflurane group (p<0,05). There were no significant differences in S-1008 protein values, central venous pressure and peripheral oxygen saturation between the groups. Conclusion: The present study demonstrated that there were similar neuroprotective effects when isoflurane and sevoflurane were administered in patients undergoing intracranial tumor surgery on cerebral ischemia, it was concluded that sevoflurane may be an alternative to isoflurane which is used frequently in intracranial tumor surgery as a volatile anesthetic agent
Isolated fallopian tubal torsion: Reproductive age case series
No full textAim To present our experiences in isolated fallopian tubal torsion (IFTT) case series, which are difficult to diagnose, in light of the literature. Methods The data of the patients diagnosed with IFTT surgically in our tertiary hospital between 2018 and 2019 were evaluated. Results Abdominal lower quadrant pain was present in all nine cases. Abdominal pain was accompanied by nausea in five of the nine cases with vomiting in four of the nine cases. Seven of the patients had pain radiating to the vagina. Only one case of IFTT was diagnosed with transvaginal ultrasonography where left tubal dilation and free fluid in the abdomen was found. Two of the nine cases were operated on with a preoperative diagnosis of IFTT. Seven cases were approached laparoscopically and two cases underwent a laparotomy. During the treatment, two of the nine cases underwent detorsion, while seven of the patients underwent a salpingectomy. Conclusion IFTT is a very rare condition. Therefore, it is difficult to diagnose as it does not come to mind at first glance. Delay of the operation reduces the chance of preserving the tube
A Comparison of the Ballistic Performances of Various Microstructures in Mil-A Armor Steel
No full textKonca, Erkan/0000-0001-8943-091XDue to their advantageous properties, there is a growing interest in developing armor steels containing fully or partially bainitic microstructures. In this study, bainitic and martensitic microstructures were obtained in rolled homogeneous armor (RHA) steel samples and their ballistic protection performances were investigated. RHA (MIL-A-12560) steel samples were subjected to isothermal heat treatments at three different temperatures, where one temperature (360 degrees C) was above the martensite formation start (Ms) temperature of 336 degrees C while the other two (320 degrees C and 270 degrees C) were below. For the assessment of the ballistic protection performance, the kinetic energy losses of the 12.7 mm bullets fired at the test samples were determined. The promising nature of the bainite microstructure was confirmed as the sample isothermally treated at 360 degrees C provided approximately 10% higher ballistic protection as compared to the regular RHA sample of tempered martensite microstructure. However, the ballistic performances of the isothermally treated samples decreased as the treatment temperature went below the Ms temperature. Following the ballistic tests, hardness measurements, impact tests at -40 degrees C, and macro- and microstructural examinations of the samples were performed. No correlation was found between the hardness and impact energies of the samples and their ballistic performances.ROKETSAN Missile Industries Inc. (Ankara, Turkey)This research was funded by ROKETSAN Missile Industries Inc. (Ankara, Turkey). The APC was paid for by the author
Evre kodlamalı sürekli dalgalı radarlarda hedef tebiti için belirsizlik fonksiyonu tekniğinin kullanılması
No full textThe goal of this thesis study is to investigate the Ambiguity Function Technique for target detection in phase-coded continuous wave radar. Also, phase shift keying techniques are examined in detail. Continuous Wave (CW) Radars, which are also known as Low Probability of Intercept (LPI) radars, emit continuous signals in time which are modulated by either frequency modulation or phase modulation techniques. Modulation of the transmitted radar signal is needed to estimate both the range and the radial velocity of the detected targets. In this thesis, Phase Shift Keying (PSK) techniques such as the Barker codes, Frank codes, P1, P2, P3, P4 codes will be employed for radar signal modulation. The use of Ambiguity Function, which is a non-linear Time- Frequency Representation (TFR), for target detection will be investigated in phasecoded CW radars for different target scenarios.M.S. - Master of Scienc
Is there any difference between pregnancy results after tubal reanastamosis performed laparotomically, laparoscopically, and robotically?
No full textIntroduction: Tubal reanastamosis offers hope to conceive again. However, there are many factors that affect the success of this procedure. In our study we aimed to compare the pregnancy rates of the surgical methods used for tubal reanastamosis in pregnancy requested after tubal sterilization. Methods: In our study we compared the rates of pregnancies after reanastamosis retrospectively in female patients under the age of 40 who underwent reanastamosis between 2010 and 2019 with laparotomic, laparoscopic and robotic methods. A single layer of 4 quadrant 6/0 number polydioxanone absorbable sutures were used in all surgical methods. A similar surgical technique was used. Results: In surgical methods (laparotomy, laparoscopy, and robotics), there was a statistical difference between the three groups in terms of operation times of surgical methods used for tubal reanastamosis (p < 0.05). Laparotomy, laparoscopy, and robotics pregnancy rates were 52.6% (n = 41), 67.3% (n = 37), 61.2% (n = 63), respectively. There was no statistical difference between groups in terms of pregnancy rates. However, odds ratio (OR) values of the laparoscopy group and robotics group probability of conception were 1.536 (95% confidence interval [CI], 0.813-2.898), 1.111 (95% CI, 0.656-1.879) higher, respectively. Conclusions: Although there is no statistical difference between the surgical methods used for tubal reanastamosis, we think that the laparoscopic surgical method may be preferable due to the shorter hospital stay. We think that the previous method of bilateral tubaligastion (BTL), the site of reanastasis, and the time between BTL and reanastomosis were effective in pregnancy success
Plasenta perkreatalı hastaların perinatal sonuçları
No full textAim: Placental invasion anomalies are rare, but it causes serious fetomaternal morbidity and mortality. In our study, we aimed to evaluate the fetomaternal results of cases with Abnormal Invasive Placenta ( Placenta Percreata).Methods: Patients who underwent a peripartum hysterectomy or whose placenta was left in uterin cavity due to placenta percreata in our hospital were retrospectively analyzed. Data of 20 patients were noted.Results: The mean age of the patients was ± SD (min-max) 33 ± 5,704 (25-46) and 60% (n = 12) of the patients had additional diseases. Fifty five percent of patients (n=11) were operated in emergency conditions and 45% (n= 9) in elective conditions. Surgical complications were 65% (n = 13) bladder injuries, 30% (n = 6) disseminated intravascular coagulation (DIC), 20% (n = 4) infection, 15% (n = 3) relapartomy and 5% (n = 1) was pulmonary embolism. Mortality increased three times (OR; 3.003 (95% CI, 0.372-24.390) in patients with a comorbidity, while 4.7 times (OR; 4.784) in emergency operations. Operations under elective conditions and previously ultrasonographic diagnosis (Odd ratio values ; 0,219 (95% CI, 0,021-2,447) and 0,615 (95% CI, 0,043-8,695), recpectively) decreased maternal mortality.Conclusion: Prenatal diagnosis and performing elective surgeries in percreata cases are important to reduce maternal mortality. Although there are various surgical complications, we think that DIC development is important in mortality and massive transfusion does not decrease the mortality.Amaç: Plasenta invazyon anomalileri nadir görülmesine rağmen ciddi fetometarnal morbidite ve mortaliteye sebep olmaktadır. Çalışmamızda plasenta invazyon anomalisi olan olguların perinatal sonuçlarını değerlendirmeyi amaçladık._x000D_
Yöntemler: Hastanemizde 2012-2014 tarihleri arasında peripartum histerektomi yapılan ve intraoperatif plasentası uterin kavitede bırakılan hastalar retrospektif olarak incelendi. 20 hastanın verileri not edildi._x000D_
Bulgular: Hastaların yaş ortalamaları ± SD (min-max) 33 ± 5,704. (25-46) saptandı. Hastaların % 60’ında (n=12) ek hastalıklar da vardı. Hastaların % 55’i (n=11) acil şartlarda ve % 45’i (n=9) elektif şartlarda opere edildi. Perkreta operasyonlarında oluşan cerrahi komplikasyonlar sıklığına göre sırasıyla % 65(n=13) mesane yaralanması, % 30 (n=6) dissemine intravaskülar kuagulasion (DIC), % 20 (n=4) enfeksiyöz komplikasyonlar ve % 5 (n=1) pulmoner emboli şeklindeydi. Maternal mortalite riskinin ek hastalığı olan hastalarda 3 kat (OR; 3,003 (95%CI, 0,372-24,390) ve acil şartlarda ameliyat olan hastalarda 4,7 kat (OR;4,784 (95%CI, 0,408-47,619) artığı saptandı. Hastaların elektif şartlarda ameliyat olması ve önceden ultrasonografik olarak tanı almış olmalarının da (OR; 0,219 (95%CI, 0,021-2,447), OR; 0,615 (95%CI, 0,043-8,695) maternal mortalite riskini azalttığı saptandı. Korelasyon analizinde maternal mortalite ile maternal yaş (0,473, p=0,035) ve masive kan_x000D_
transfüzyonunun (0,562, p=0,010) pozitif korelasyon, postoperatif hemoglobin değeri ile de negatif kolerasyon gösterdiği saptanmıştır (-0,723, p= 0,010)._x000D_
Sonuç: Plasenta perkreatalı hastalarda, prenatal tanı konulmuş olması ve hastaların elektif şartlarda opere edilmesi maternal mortalite riskinin azaltılması açısından önem arz etmektedir. Çeşitli cerrahi komplikasyonlar olmasına rağmen DIC tablosu mortalite açısından önemlidir ve bu tabloda masif transfüzyon da mortaliteyi azaltmamaktadır
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