Titania (TiO2) metal oxide nanomaterials

Doktora TeziBu tezde, metal oksit bir malzeme olan TiO2 (titanya)'nın, doğada en yaygın olarak bulunan polymorfları anataz ve rutil yapılarının hacimsel ve bunlara dayanan küresel nanoparçacıkları ile kare kesitli nanotellerinin yapısal ve dinamik özellikleri sıcaklığa bağlı olarak moleküler dinamik simülasyon (MD) yöntemi kullanılarak incelenmiştir. Hacimsel yapıların simülasyonlarında sabit parçacık sayısı, basınç ve sıcaklıklı (NPT) toplulukları ile tek ve çift fazlı simülasyon tekniği, nanoparçacık simülasyonlarında ise sabit parçacık sayısı, hacim ve sıcaklıklı (NVT) toplulukları ile tek fazlı simülasyon tekniği kullanılmıştır. MD simülasyonlarında atomlar arası etkileşmeleri tanımlamak için Matsui Akaogi kuvvet alanı potansiyeli kullanılmıştır. Çalışılan tüm sistemlerin erime noktaları, enerji hacim, enerji sıcaklık, entalpi sıcaklık, ısı sığası sıcaklık, değişim eğrileri, lindemann erime kriteri ve yapısal olarak çiftler dağılım fonksiyonlarının (PDF), difüzyon, gibi sıvı karakteristik özellikleri incelenerek belirlenmiştir. Hacimsel ve nanoparçacık yapıların erime sıcaklıkları birbirleri ile karşılaştırıldıkların da, hesaplanan erime sıcaklıklarının NP boyutuna bağlı olarak değiştiği gözlenmiştir. NP boyutu artıkça erime sıcaklığı da artmaktadır. Bu değişim çeşitli termodinamik modeller ile karşılaştırılarak incelenmiştir. Kare kesitli anataz ve rutil nanotellerde telin kesitinin artmasıyla orantılı olarak erime sıcaklığıda artmaktadır. 2.25nm çaplı rutil nanotelin erime sürecini tamamladıktan sonra koparak küresel NP haline geldiği gözlenmiştir.AbstractIn this thesis, two most common phases, anatase and rutile structures, of TiO2 (titania) have been investigated by using the molecular dynamics (MD) simulation method. The temperature dependent structural and dynamic properties of bulk phases, and spherical nanoparticles and nanowires with square cross-section have been studied. Size effect on the physical properties of TiO2 (titania) nanomaterials have been also presented. Two phase simulation technique with a fixed particle number, pressure and temperature (NPT) ensemble in bulk simulations, fixed particle volume and temperature (NVT) ensembles in NP simulations have been used during the MD simulations. In MD calculations, Matsui Akaogi (MA) force field potential is used to describe the interactions between atoms. In order to determine the melting temperatures of the systems, the liquid characteristic properties including energy volume, energy temperature, enthalpy temperature, heat capacity temperature, Lindemann index, pair distribution functions and diffusion curves have been invastigated and compared. When the bulk and NP melting temperatures are compared with each other, it has been observed that the calculated melting temperatures are related to the size of NP. The melting temperature of NP increases as the size of NP increases. The melting temperature of spherical anatase nanoparticles is lower than that of bulk melting temperature. Several thermodynamical models are employed and compared with the calculated melting temperatures of different size nanoparticles on order to understand the melting process. The melting temperatures of anatase and rutile nanowires with square cross-section are also increasing with the increasing size. Moreover, the rutile nanowire with an approximate diameter of 2.25nm collapes to a spherical nanoparticle after completing the melting process

The Use of Human Epididymis 4 and Cancer Antigen 125 Tumor Markers in the Benign or Malignant Differential Diagnosis of Pelvic or Adnexal Masses

Background: Ovarian cancer is one of the highest mortality cancers in gynaecology. Discrimination of benign masses from malignant ones may sometimes become a challenge for the clinician since there is not a reliable tumour marker, thus some unnecessary, highly morbid operations can be performed. Aims: To explore the efficacy of human epididymis 4 (HE 4) and cancer antigen 125 (CA 125) markers in differentiating malignant and benign pelvic masses of ovarian origin and to identify the cut-off points for those markers. Study Design: Prospective study. Methods: Fifty-one patients who were diagnosed and planned to undergo surgery for ovarian mass between June 2008 and December 2008 were enrolled into this study. Preoperative venous blood samples were taken and frozen for marker investigation and final diagnoses were concluded by histopathological examination. After recruitment of all cases CA 125 and HE 4 levels were evaluated. Results: The statistical analysis did not indicate any statistically significant difference between the CA 125 levels of the patients with malignant and benign adnexal masses (p=0.105). The HE 4 levels of the patients with malignant adnexal masses were higher at a statistically significant level compared to the patients with benign adnexal masses (p=0.002). For HE 4 tumour marker and at the cut-off point of >25 pM, sensitivity was 1, specificity 0.40, positive cut-off value 0.19, negative cut-off value 1, accuracy 0.47 and positive likelihood ratio 1.65. Conclusion: Human epididymis 4 is a better diagnostic tool than CA 125 in benign-malignant discrimination of adnexal masses. The cut-off value of 25 pmol/L for human epididymis 4 will contribute to providing proper guidance to patients with adnexal masses and applying the proper treatment method

Serum and follicular fluid concentration of stem cell factor in PCOS

Background: Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women, which affects 5 to 20% of women in the reproductive age worldwide. This study aimed to compare the levels of SCF in serum and follicular fluid of PCOS patients with those of non-PCOS group and to investigate the relationship of SCF levels with ICSI success.Methods: This is an observational case control study that included the patients who underwent ICSI in the Infertility-IVF center at Ankara University Faculty of Medicine and in a private IVF center between March 2016 and February 2017. The study group consisted of 57 PCOS patients diagnosed according to the Rotterdam criteria and the control group consisted of 75 patients with normofollicular and regular menstrual cycles. Serum and follicular fluid samples were taken on day of oocyte retrieval. Serum and follicular fluid SCF levels were determined by ELISA using the SCF ELISA kit..Results: Serum and follicular fluid SCF levels in PCOS patients were found to be lower than in non-PCOS group. sSCF and ffSCF were statistically significantly higher who had clinical pregnancy than those who had no clinical pregnancy in the PCOS group.Conclusions: SCF levels are low in serum and follicular fluid in patients with PCOS and that the increase in SCF levels is associated with an increase in oocyte maturation and clinical pregnancy rates in PCOS.

FOXA1 is associated with high tumor grade, myometrial invasion and lymph node invasion in endometrial endometrioid carcinoma

Objectives: FOXA1 expression has been demonstrated in several hormone-dependent cancers. However, data are limited concerning the role of FOXA1 in endometrial cancers. The present study aimed to investigate FOXA1 expression via the microarray technique in benign hyperplasia, endometrial intraepithelial neoplasia, and endometrial endometrioid carcinoma. We also aimed to determine whether there were any associations between FOXA1 expression, tumor grade, myometrial invasion and lymphatic invasion.Material and methods: Paraffin-embedded sections prepared from samples obtained from 114 patients who underwent surgical hysterectomy or curettage were analyzed. Data were retrieved from digitally-stored medical records. Tissue microarrays were prepared from formalin-fixed, paraffin-embedded tissue blocks. Full tumor sections were used for immunohistochemical analysis performed.Results: Carcinomas with nuclear grade 3 had higher FOXA1 values than others, while grade 2 carcinomas also had higher FOXA1 values relative to grade 1 (p < 0.001). FOXA1 values of FIGO stage III carcinomas were significantly higher than others and stage II values were also significantly higher than stage I FOXA1 values (p < 0.001). Patients with myometrial and lymph node invasion had significantly higher FOXA1 values than others (p < 0.001 and p = 0.047, respectively). FOXA1 had 91.30% sensitivity, 63.60% specificity and 77.78% accuracy for predicting the presence of myometrial invasion with a cut-off value of 9.Conclusions: FOXA1 expression is higher in endometrial endometrioid carcinoma compared to benign endometrial hyperplasia or intraepithelial neoplasia. In patients with endometrial endometrioid carcinoma, high FOXA1 expression is associated with high tumor grade, myometrial and lymph node invasion. However, FOXA1 expression is not associated with lymphovascular or cervical invasion

Evaluation of Incidence and Clinical Features of Antibody-Associated Autoimmune Encephalitis Mimicking Dementia

Background. Anti-neuronal autoimmunity may cause cognitive impairment that meets the criteria for dementia. Objective. Our aim was to detect the incidence and clinical features of autoimmune encephalitis imitating clinical findings of primary dementia disorders and to delineate the validity of anti-neuronal antibody screening in dementia patients. Methods. Fifty consecutive patients fulfilling the clinical criteria for primary dementia, 130 control patients, and 50 healthy controls were included. Their sera were investigated for several ion channel and glutamic acid decarboxylase (GAD) antibodies by a cell-based assay, radioimmunoassay, and ELISA, as required. Results. Sixteen patients satisfying dementia criteria had atypical findings or findings suggestive of autoimmune encephalitis. N-methyl-D-aspartate receptor (NMDAR) antibody was detected in a patient with dementia, Parkinsonism, and REM sleep behavior disorder (RBD) fulfilling the criteria for dementia with Lewy bodies (DLB). One control patient with bipolar disease displayed low anti-GAD antibody levels. Conclusions. Our study showed for the first time the presence of parkinsonism and RBD in an anti-NMDAR encephalitis patient mimicking DLB. Although autoimmune encephalitis patients may occasionally present with cognitive decline, most dementia patients do not exhibit anti-neuronal antibodies, suggesting that routine analysis of these antibodies in dementia is not mandatory, even though they display atypical features

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Atomic transport properties of ionic liquids

Yüksek Lisans TeziBu çalışmada ergimiş bakır halojenürlerin CuX (X=Cl,Br, I), bakır oksit (CuO), bakır sülfür (CuS) ve baryum bromür (BaBr) sistemlerinin yapısal ve atomik taşıma özellikleri araştırılmıştır. Ergimiş iki bileşenli karışımdaki iyonlar arası etkileşme potansiyelleri, katı iyon modeli ve polarize edilmiş iyon modellerinin (PIM) farklı fonksiyonel formları ile hesaplanmıştır. Vashista – Rahman katı iyon model potansiyelinin iki farklı versiyonu ele alınmış; Tatlıpınar-Akdeniz-Pastore-Tosi (TAPT) tarafından parametrize edilen PIM potansiyeli bu tez çalışmasında yeniden düzenlenerek (MTAPT) tezde çalışılan sistemlere ilk kez uygulanmıştır. İncelenen sistemlerin kısmi statik yapı faktörleri, çiftler dağılım fonksiyonları sıvıhal integral teorilerinden Varyasyonel Hypernnetted Chain altındaki Hypernetted Chain yaklaşımı ile elde edilmiştir. Hesaplanan tüm yapısal özellikler, iyonlar arası çiftler etkileşme potansiyelleri ile birlikte sistemlerin atomik dinamik özelliklerinden ortalama kare yerdeğiştirme, hız oto korelasyon fonksiyonları, ve her bir iyonun karışımdaki self difüzyon katsayılarının hesaplanmasında giriş verileri olarak kullanılmıştır. Diğer taraftan, deneysel yapı faktörlerinden yola çıkarak yaklaşık ters dönüşüm formülü ile karışımdaki iyon çiftleri arasındaki etkileşmeleri tanımlayacak ters potansiyeller oluşturulmuştur. Elde edilen ters potansiyeller de dinamik yapı hesaplamalarında kullanılmıştır. Bu tezde incelenen iki bileşenli sistemlerinin hem direkt hem de ters yöntem ile hesaplanan yapısal, atomik dinamik ve transport özellikleri, kendi aralarında, deneysel sonuçlar, moleküler dinamik simülasyon sonuçları ve diğer teorik hesaplamalardan elde edilen sonuçlarla karşılaştırılmıştır.AbstractIn this work, the structural and atomic transport properties of cupper halides CuX(X=Cl,Br,I), cupper oxide (CuO), cupper sulfide and barium bromine (BaBr) systems have been investigated. Interionic interaction potentials in molten two component mixtures have been calculated with different functional forms of rigid ion model (RIM) and polarizable ion model (PIM) potentials. While the two different versions of Vashista – Rahman (VR) RIM potential have been considered; the PIM potential which was parametrized by Tatlıpınar-Akdeniz-Pastore-Tosi as TAPT has been modified and first applied to these systems studied in this thesis. The partial structure factors and pair distribution functions have been obtained by using the Hypernetted Chain approximation (HNC). under Variational Hypernetted Chain (VMHNC) which is one of the liquid state theory The computed structural properties together with the inter ionic effective pair potentials have been used as input data for the calculation of atomic dynamic properties of the systems such as mean square displacements, velocity auto correlation functions, and diffusion coefficents of each ion in the mixture. On the otherhand, the inverse potential which defining interactions between the ion pairs in the mixture has been constructed from the experimental structure data using the approximate inversion formula. The constructed potential has been used as input for dynamic structure calculations. The structural, atomic dynamic and transport properties of the systems investigated in this thesis which are calculated using both direct and inverse method have been compared with each other and those obtained from experiments, molecular dynamics and other theoretical calculations

Blood pressure relationship to nitric oxide, lipid peroxidation, renal function, and renal blood flow in rats exposed to low lead levels

The results of experiments designed to show that inhibition of nitric oxide production in rats exposed to low lead levels increases vascular resistance, decreases renal blood flow and glomerular function, and enhances oxidative stress. Forty-five adult male Sprague-Dawley rats were divided into four groups. Group A was used as controls and consisted of rats that received no treatment; group B acted as NO-inhibited controls by receiving L-NAME (N-G-nitro-L-arginine methyl ester) as the NO inhibitor; group C was injected intraperitoneally with 8 mg/kg lead acetate for 2 wk; and group D receiving lead acetate Plus L-NAME