126 research outputs found

    Experimental evaluation of cyclic fatigue resistance of four different nickel-titanium instruments after immersion in sodium hypochlorite and/or sterilization

    Get PDF
    NiTi instruments have a high risk of separation due to torsional or flexural fatigue (cyclic fatigue). Chemomechanical preparation, cleaning procedures, chemical disinfection and sterilization cause the corrosion of endodontic instruments that may weaken the fracture resistance of the instruments. Objective To assess the effects of NaOCl immersion and autoclave sterilization on the cyclic fatigue resistance of ProFile, FlexMaster, Mtwo and TwistedFiles NiTi instruments (tip size 25, 0.06 taper, n=160). Material and Methods The instruments (n=10 for each subgroup) were dynamically immersed in NaOCl; immersed in NaOCl and sterilized in one autoclave cycle; 5 cycles immersed in NaOCl and sterilized in autoclave and not immersed in NaOCl and not sterilized (control group). Dynamic cyclic fatigue resistance was tested. The number of cycles to failure (NCF) were statistically analyzed (P;.05). Conclusions Cyclic fatigue resistance of the tested NiTi instruments cannot be adversely affected by NaOCl immersion and autoclave sterilization. Production process (TwistedFiles) or design (Twisted Files, FlexMaster, Mtwo and ProFile) of the instruments can influence their cyclic fatigue resistance

    Survival outcomes of hypomethylating agents maintenance therapy in new diagnosed AML patients: Real experience data

    Get PDF
    OBJECTIVE: Acute myeloid leukemia (AML) is a hematological malignancy that frequently affects elderly population. With introducing the hypomethylating agents (HMAs) in elderly AML treatment, survival rates and quality of life have improved. However, long-term management in elderly and frail patients is still a challenge. In the present study, we aimed to determine whether HMA maintenance therapy is required until disease progression in frail and elderly AML patients by examining with a real-life data.METHODS: In a multicenter study, we analyzed non-promyelocytic elderly AML patients who were treated with first-line azacitidine or decitabine monotherapy in two different groups, retrospectively. While patients were treated with HMA until progression in the maintenance group, 6+3 cycles of azacitidine or decitabine were administered as a standard care of elderly AML patients in the non-maintenance group. Survival outcomes were compared between the groups.RESULTS: HMA therapy was maintained until progression in 20 patients, and HMA therapy was terminated after 6+3 cycles in 21 patients. Patients received a median of 6 (1-14) HMA cycles during follow-up time. The median 7.5 months of overall survival were observed (2-17 months) in maintenance and 3 months (1-13 months) in non-maintenance groups (p=0.001).CONCLUSION: Despite long-term exposure to HMA may appear as a risk factor for complications and toxicities in elderly and frail AML patients, the maintenance of therapy until disease progression provides a significant survival advantage. Therefore, we suggest that HMA therapy should continue until disease progression regardless the sort of HMA

    CT dose management for neurologic events in patients with cardiac devices: Radiation exposure variation in patients with cardiac devices

    Get PDF
    PURPOSE:To compare the inter-center cranial computed tomography (CT) acquisition rates, CT findings, CT related radiation dose, and variability of CT acquisition parameters for neurologic events among patients with implantable cardioverter-defibrillator (ICD) or left ventricular assist device (LVAD).METHODS:A total of 224 patients [ICD group (n = 155) and LVAD group (n = 69)] who had at least one cranial CT scan were enrolled from three medical centers. The variability and effect of the number, indication, and findings of cranial CT scans as well as CT acquisition parameters including tube potential, tube current, tube rotation time (TI), slice collimation (cSL), and spiral or sequential scanning techniques on CT dose index volume (CTDIvol), total dose length product (DLP) were analyzed.RESULTS:The mean DLP value of Center A and mean CTDIvol values of Center A and C were significantly lower than Center B (p < 0.001). The mean CTDIvol and DLP values in the ICD group were substantially lower than the LVAD group (p<0.001). The most potent parameters causing the changes in CTDIvol and DLP were kV, mAs values, and CT scanning technique as sequential or spiral according to multivariate linear regression analysis.CONCLUSION:Cranial CT acquisition parameters and radiation doses vary significantly between centers, which necessitates optimization of cranial CT protocols to overcome the cumulative radiation dose burden in patients with neurologic events

    Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

    Get PDF
    Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

    Diş pulpasi mezenkimal kök hücrelerin yaş gruplarına bağlı karakterizasyonu

    No full text
    Mezenkimal kök hücreler kendini yenileme ve çeşitli hücrelere farklılaşabilme özelliğine sahip hücrelerdir. Diş pulpası kök hücreleri, en önemli kolay elde edilebilir mezenkimal kök hücre kaynaklarından biri olmakla birlikte hızlı çoğalma özelliği ve uygunuyaranlar ile farklılaştırıldığında mineralize doku oluşturma potansiyelleri ile bilinmektedir. Kök hücre biyolojisi ve doku mühendisliği alanlarında görülen gelişmeler, hücre aracılı rejeneratif tedavi seçeneklerinin önünü açmıştır. Çalışmamızda farklı yaş gruplarından elde edilen diş pulpası kök hücrelerin karakterizasyonu ve gruplar arasında diş pulpası kök hücre oranlarının karşılaştırılması amaçlanmışır. 18-24 yaş, 25 yaş ve üstü kişilerden elde edilen diş pulpalarından hücre kültürü ile diş pulpası kök hücreleri büyütülmüştür. Elde edilen diş pulpası kök hücreleri, adipojenik, osteojenik vekondrojenik hücrelere farklılaştırılmıştır. Çalışmamızda 18-24 yaş, 25 yaş ve üstü kişilerden elde edilen diş pulpaları, içeriklerindeki diş pulpası mezenkimal kök hücreleri açısından akım sitometri ie karşılaştırılmıştır. Mezenkimal kök hücre belirteçleri olan CD13, CD 105 ve hematopoietik kök hücre belirteci olan CD 45 ile değerlendirilmişlerdir. Yapılan istatistiksel analizde yaş grupları arasında anlamlı bir fark bulunamamıştır.Mesenchymal stem cells have the ability to self-renewal and differentiate into various cells. Dental pulp stem cells are one of the most important easily obtainable sources of mesenchymal stem cells, they are known for their rapid proliferation and their potential to form mineralized tissue when differentiated with appropriate stimuli. Advances in stem cell biology and tissue engineering have paved the way for cell-mediated regenerative treatment options. In our study, we aimed to compare the ratios of dental pulp stem cells obtained from different age groups. Dental pulp stem cells were grown by cell culture from dental pulps obtained from people aged 18-24 and 25 years and over. The obtained dental pulp stem cells were differentiated into adipogenic, osteogenic and chondrogenic cells. In our study, dental pulps obtained from individuals aged 18-24, 25 years and above were compared with flow cytometry in terms of dental pulp mesenchymal stem cells in their contents. They were evaluated with the mesenchymal stem cell markers CD13, CD 105 and hematopoietic stem cell markers CD 45. In the statistical analysis, there was not any significant difference between age groups

    Sıçan beyninde kronik nikotin uygulamasının mezokortikolimbik sistem yapılarında eksprese edilen cart peptid ve mrna'sına etkisi

    No full text
    Kokain ve amfetamin ile düzenlenen transkript mRNA ve peptidleri mezokortikolimbik sistemde yoğun olarak bulunmaktadır. Anatomik olarak CART ile mezokortikolimbik sistem arasındaki sıkı ilişkinin yanında, CART peptidleri, mezokortikolimbik sistem ile fonksiyonel olarak da ilişki içerisindedir. CART'ın kokain, amfetamin, alkol gibi madde bağımlılıklarındaki rolünü gösteren çalışmalar bulunmaktadır. Nikotin, bağımlılık yapıcı etkilerini mezokortikolimbik dopaminerjik sistemi uyararak göstermektedir. Sunulan tez çalışmasında nikotinin mezokortikolimbik sistemde CART üzerine olan etkilerinin araştırılması amaçlanmıştır. Nikotin gruplarına üç farklı dozda nikotin (0.2, 0.4, 0.6 mg/kg) beş gün boyunca subkutan olarak enjekte edilmiş, 6. gün, son enjeksiyondan sonra sıçanlar dekapite edilmiştir. Mezokortikolimbik sistemi oluşturan, medial prefrontal korteks (mPFC), nukleus akumbens (NAc), dorsal striatum (DST), amigdala (AMG), lateral hipotalamik alan (LHA), ventral tegmental alan (VTA) yapıları diseke edilmiştir. Bu bölgelerden elde edilen CART mRNA ve peptidleri kantitatif real-time PCR ve Western Blot analizi ile ölçülmüştür. mPFC'de, 0.4 ve 0.6 mg/kg nikotin uygulanan gruplarda, VTA'da 0.2 ve 0.6 mg/kg nikotin uygulanan gruplarda CART peptid düzeyleri anlamlı şekilde azalmışır. AMG'de , 0.4 ve 0.6 mg/kg nikotin uygulanan gruplarda CART mRNA düzeyleri artmıştır. Nikotinin, NAc, DST, LHA'da CART mRNA ve peptid düzeylerine anlamlı bir etkisi saptanmamıştır. Nikotin CART'ın ifadesini mezokortikolimbik sistemde yer alan mPFC, VTA, AMG'de düzenlemektedir.Cocaine and amphetamine regulated transcript (CART) mRNA and peptides are intensely expressed in the brain regions comprising mesocorticolimbic system. In addition to anatomical observations, there is also physiological evidence linking CART peptides with mesocorticolimbic system. Studies suggest that CART peptides have a role in drug abuse. The initiation of nicotine addiction involves mesocorticolimbic system. The aim of the study is to examine the effects of nicotine on CART expression in the mesocorticolimbic system. Three different doses of nicotine (0.2, 0.4, 0.6 mg/kg free base) were injected subcutaneously for 5 days and on the 6. day rats were decapited following a challange dose. CART mRNA and peptide levels in medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum (DST), amygdala (AMG), lateral hipotalamic area (LHA), ventral tegmental area (VTA) were measured by quantitative real-time PCR (qPCR) and Western Blot analysis. In the mPFC, 0.4 and 0.6 mg/kg nicotine, in the VTA 0.2 and 0.6 mg/kg nicotine decreased CART peptide levels. In the AMG 0.4 and 0.6 mg/kg nicotine increased CART mRNA levels . Nicotine did not affect CART peptide and mRNA expression in the NAc, DST, LHA. Nicotine regulate CART expression in the mPFC, VTA and AMG which are located in the mesocorticolimbic system

    İki fark risk analiz metodu kullanılarak seçilmiş Türk petrol sahalarının beklenen parasal değerlerinin hesaplanması

    No full text
    Most investments in the oil and gas industry involve considerable risk with a wide range of potential outcomes for a particular project. However, many economic evaluations are based on the أmost likelyؤ results of variables that could be expected without sufficient consideration given to other possible outcomes and it is well known that initial estimates of all these variables have uncertainty. The data is usually obtained during drilling of the initial oil well and the sources are geophysical (seismic surveys) for formation depths and areal extent of the reservoir trap, well logs for formation tops and bottoms, formation porosity, water saturation and possible permeable strata, core analysis for porosity and saturation data and DST (Drill-Stem Test) for possible oil production rates and samples for PVT (Pressure Volume Temperature) analysis to obtain FVF (Formation Volume Factor) and others. The question is how certain are the values of these variables and what is the probability of these values to occur in the reservoir to evaluate the possible risks. One of the most highly appreciable applications of the risk assessment is the estimation of volumetric reserves of hydrocarbon reservoirs. Monte Carlo and moment technique consider entire ranges of the variables of Original Oil in Place (OOIP) formula rather than deterministic figures. In the present work, predictions were made about how statistical distribution and descriptive statistics of porosity, thickness, area, water saturation, recovery factor, and oil formation volume factor affect the simulated OOIP values. The current work presents the case of two different oil fields in Turkey. It was found that both techniques produce similar results for 95%. The difference between estimated values increases as the percentages decrease from 50% and 5% probability.M.S. - Master of Scienc
    corecore