Gas sensing properties of carbon nanotubes modified with calixarene molecules measured by QCM techniques

1st International Congress on Advances in Applied Physics and Materials Science (APMAS), Antalya, Turkey, 12-15 May, 2011This study focuses on the characterization and optimization of calixarene modified carbon nanotube thin films for gas detection. Calixarene molecules were synthesized individually by considering their functional groups to attract the gas. Calixarene modified carbon nanotube based sensors were fabricated using drop-casting method on a quartz crystal microbalance gold electrode. Carbon monoxide, carbondioxide, oxygen and dry air were used as active gases for adsorption process, while high-purity nitrogen gas was used for desorption process. The selectivity and sensitivity of calixarene modified carbon nanotube are investigated in detail. Our experimental results show that functional calixarene modified carbon nanotube coated quartz crystal microbalance sensors are very sensitive and selective to gas of CO 2 at room temperature operation.This research was supported by TÜBİTAK under project numbers TBAG 109 T240 and 110 M349 and IYTE research project number 2010IYTE2

Effect of simulated gastric acid on aesthetical restorative CAD-CAM materials' microhardness and flexural strength

Background: Gastric acid, which is among erosive substances, gradually rises to the mouth in individuals with reflux and bulimia nervosa disorders, and this causes various effects on dental restorations. Aim: The objective of this study is in vitro investigation of gastric acid's effect on flexural strength and hardness on aesthetic restorative computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: For this study, four materials have been used, namely Enamic (Vita), Superfect Zir (Aidite) Zirconia, IPS e.max CAD (Ivoclar Vivadent), and Mark II (Vita). From these four different materials, 24 samples with 14 × 4 × 1 dimensions in rectangular prism form are used, which makes a total of 96 samples. One group was separated as the control group, while the rest was allowed to wait at 37°C, 5 ml gastric acid for 96 hours. Hardness value and flexural strengths were measured as pre-exposure and post-exposure to gastric acid. Results: There is a statistically significant difference between the groups in terms of the amount of decrease in the mean hardness after exposure to gastric acid compared to pre-exposure values (p: 0,000; P 0.05). There is a statistically significant difference between the groups in terms of the average flexural strength after exposure to the acid. Conclusions: According to the data obtained, it was concluded that exposure to gastric acid affects the hardness and flexural strength properties of dental restorative ceramic materials

Diagnosis of invasive fungal infection in patients with solid organ transplants: How to approach?

Invasive fungal infection (IFI) is associated with high morbidity and mortality in solid organ transplant recipients. Candida and Aspergillus species are the most frequent agents of IFIs. Cryptococcus spp, non-Aspergillus moulds, endemic fungi and Pneumocystis jirovecii are less commonly determined. Diagnosis of IFI can be difficult because the signs and symptoms are not specific, and diagnostic techniques have limited sensitivity and specificity. In this review, epidemiological characteristics, clinical course, risk factors and diagnostic tests of common IFIs in solid organ transplant recipients are discussed. © 2019, AVES. All rights reserved

Temporary pacemaker with left bundle branch block image in ECG [Geçici kalp pilinde EKG'de sol dal bloğu görüntüsü]

[No abstract available

Application of ATC/DDD methodology to evaluate perioperative antimicrobial prophylaxis

Objective To evaluate quality of perioperative antibiotic prophylaxis (PAP) and to calculate the cost per procedure in a Turkish university hospital. Setting A 352-bed teaching hospital in Denizli, Turkey. Method An prospective audit was performed between July and October 2010. All clean, clean-contaminated and contaminated elective surgical procedures in ten surgical wards were recorded. Antimicrobial use was calculated per procedure using the ATC-DDD system. The appropriateness of antibiotic use for each procedure was evaluated according to international guidelines on PAP. In addition, the cost per procedure was calculated. Results Overall, in 577 of the 625 (92.3%) of the studied procedures, PAP was used. PAP was indicated in 12.5% of the group where it was not used, and not indicated in 7.1% of the group where it was used. Unnecessarily prolonged antimicrobial prophylaxis was observed in 56.9% of the procedures, mean duration was 2.6 ± 2.7 days. The most frequently used antimicrobials were cefazolin (117.9 DDD/100-operation) and sulbactam/ ampicillin (102.2 DDD/100-operation). The timing of the starting dose was appropriate in 545 procedures (94.5%). In the group that received PAP, only 80 (13.7%) of the procedures were found to be fully appropriate and correct. The density of antimicrobial use per operation was 2.8 DDD. The mean cost of the use of prophylactic antimicrobials €18.6 per procedure. Conclusion The density of antimicrobial use in PAP was found to be very high in our hospital. Antibiotic overuse extended into the postoperative period. © 2011 CARS

Metformin-Loaded Polymer-Based Microbubbles/Nanoparticles Generated for the Treatment of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disease that is increasingly common all over the world with a high risk of progressive hyperglycemia and high microvascular and macrovascular complications. The currently used drugs in the treatment of T2DM have insufficient glucose control and can carry detrimental side effects. Several drug delivery systems have been investigated to decrease the side effects and frequency of dosage, and also to increase the effect of oral antidiabetic drugs. In recent years, the use of microbubbles in biomedical applications has greatly increased, and research into microactive carrier bubbles continues to generate more and more clinical interest. In this study, various monodisperse polymer nanoparticles at different concentrations were produced by bursting microbubbles generated using a T-junction microfluidic device. Morphological analysis by scanning electron microscopy, molecular interactions between the components by FTIR, drug release by UV spectroscopy, and physical analysis such as surface tension and viscosity measurement were carried out for the particles generated and solutions used. The microbubbles and nanoparticles had a smooth outer surface. When the microbubbles/nanoparticles were compared, it was observed that they were optimized with 0.3 wt % poly(vinyl alcohol) (PVA) solution, 40 kPa pressure, and a 110 μL/min flow rate, thus the diameters of the bubbles and particles were 100 ± 10 μm and 70 ± 5 nm, respectively. Metformin was successfully loaded into the nanoparticles in these optimized concentrations and characteristics, and no drug crystals and clusters were seen on the surface. Metformin was released in a controlled manner at pH 1.2 for 60 min and at pH 7.4 for 240 min. The process and structures generated offer great potential for the treatment of T2DM