Development of metal organic framework filled PDMS/PI composite membranes for biobutanol recovery

Aslıhan Çalhan,Sennur Deniz,Julio Romero,Ayça Hasanoğlu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.9

Butanol is a second generation biofuel with high potential to replace fossil fuels in the future. The main drawbacks in biobutanol production are the low yields of operation and high cost of separation. In this study, n-butanol recovery from its aqueous solutions was carried out by pervaporation as an alternative separation process using polyimide supported polydimethylsiloxane membranes, which were especially prepared for this purpose. To enhance the separation efficiency of the membrane, metal organic framework fillers of MOF-199 were included in its structure. Several combinations of polyimide supported PDMS active layered membranes were prepared with the fillers in each layer of the membrane, in both layers of membrane and membranes without fillers. Thus, the effect of the fillers on the separation performance was investigated. It was found that the inclusion of MOF-199 enhances the membrane performance; meanwhile, the support layer also contributes to mass transfer of n-butanol. Furthermore, the effect of the process parameters on the pervaporation performance was investigated. Results of pervaporation tests indicate that the developed membranes have a good potential for n-butanol recovery from aqueous mixtures.

Effects of Humic Acid in Remediation of Heavy Metals (pb And Cd) with Canola Plants (brassica Napus L.)

Aslıhan Esringu,Metin Turan,Melek Ekinci,Sezai Ercisli 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Investigation of the prevalence and main features of skull-base anomalies and characteristics of the sphenoid sinus using cone-beam computed tomography

Akbulut Aslıhan,Demirel Oğuzhan,Orhan Kaan 대한구강악안면외과학회 2022 대한구강악안면외과학회지 Vol.48 No.4

Objectives: This study aimed to define the prevalence and characteristics of skull base anomalies and the features of sphenoid sinus pneumatization (SSP). Materials and Methods: Five hundred cone-beam computed tomography scans were evaluated retrospectively for the presence of fossa navicularis magna (FNM), canalis basilaris medianus (CBM), sphenoid emissary foramen (SEF), and/or Onodi cells (OC). Patterns of the SSP and sphenoid sinus mucosa dimensions (SSMD) were also recorded. Results: The prevalence of FNM, CBM, SEF, and OC was 26.0%, 22.4%, 47.4%, and 18.4%, respectively. Two hundred sixty-two (52.4%) sellar-type SSP were defined, followed by post-sellar 191 (38.2%), pre-sellar 31 (6.2%), and conchal 16 (3.2%) types. The frequency of SSMD less than 1 mm, 1-3 mm, and greater than 3 mm was 40.6%, 38.4%, and 21.0%, respectively. An SEF was detected more frequently in females, while SSMD greater than 3 mm was more frequent in males. An FNM was more prevalent in the 18-29 and 30-39 age groups and SEF was significantly less fre-quent in patients over 60 years of age compared to other age groups. A sinus mucosa larger than 3 mm was more common in the younger than 18 year group. The frequency of post-sellar-type pneumatization was lower in patients younger than 18 years. Conclusion: Skull-base anomalies are common and may be detected incidentally during imaging procedures. The sphenoid sinus, its variations, and pneumatization patterns should also be taken into consideration in imaging procedures performed for various purposes.

A comparison of metabolic engineering strategies applied in Yarrowia lipolytica for β-carotene production

Redife Aslıhan Uçar,Furkan Demirgül,Ömer Şimşek,Hüseyin Erten 한국생물공학회 2024 Biotechnology and Bioprocess Engineering Vol.29 No.1

With a better understanding of the health benefi ts of β -carotene, the precursor of vitamin A, as well as its coloring property, the need for this carotenoid has increased in various sectors. In order to meet the increasing demand effi ciently, cheaply, and sustainably, interest in heterologous β -carotene production through metabolic engineering strategies has increased in recent years. In this context, although it is not a native producer of β -carotene, Yarrowia lipolytica yeast stands out due to its metabolic, physiological, and genomic properties. Successful results have been obtained by using a series of engineering strategies, including biosynthesis pathway engineering, morphological engineering, and fermentation engineering strategies, in the production of heterologous β -carotene from Y . lipolytica . However, these strategies have various strengths and weaknesses against each other, and there are also some points open to improvement. In this review, the engineering strategies that have been applied and have the potential to be applied for the production of β -carotene from Y . lipolytica have been examined in depth, including their advantages and disadvantages, and compared with each other. Moreover, a future perspective has been presented to increase the potential of using Y . lipolytica yeast as a cell factory in β -carotene production.

Evaluation of translucency of monolithic zirconia and framework zirconia materials

İlkin Tuncel,Işıl Turp,Aslıhan Üşümez 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.3

PURPOSE The opacity of zirconia is an esthetic disadvantage that hinders achieving natural and shade-matched restorations. The aim of this study was to evaluate the translucency of non-colored and colored framework zirconia and monolithic zirconia. MATERIALS AND METHODS The three groups tested were: non-colored framework zirconia, colored framework zirconia with the A3 shade according to Vita Classic Scale, and monolithic zirconia (n=5). The specimens were fabricated in the dimensions of 15×12×0.5 mm. A spectrophotometer was used to measure the contrast ratio, which is indicative of translucency. Three measurements were made to obtain the contrast ratios of the materials over a white background (L*w) and a black background (L*b). The data were analyzed using the one-way analysis of variance and Tukey HSD tests. One specimen from each group was chosen for scanning electron microscope analysis. The determined areas of the SEM images were divided by the number of grains in order to calculate the mean grain size. RESULTS Statistically significant differences were observed among all groups (P<.05). Non-colored zirconia had the highest translucency with a contrast ratio of 0.75, while monolithic zirconia had the lowest translucency with a contrast ratio of 0.8. The mean grain sizes of the non-colored, colored, and monolithic zirconia were 233, 256, and 361 nm, respectively. CONCLUSION The translucency of the zirconia was affected by the coloring procedure and the grain size. Although monolithic zirconia may not be the best esthetic material for the anterior region, it may serve as an alternative in the posterior region for the bilayered zirconia restorations

Evaluation of the bond strength between aged composite cores and luting agent

Caner Ozturk,Alirıza Tuncdemir,Aslıhan usumez,Fatma Cebe,Serdar Polat 대한치과보철학회 2015 The Journal of Advanced Prosthodontics Vol.7 No.2

PURPOSE The aim of this study was to evaluate effect of different surface treatment methods on the bond strength between aged composite-resin core and luting agent. MATERIALS AND METHODS Seventy-five resin composites and also seventy-five zirconia ceramic discs were prepared. 60 composite samples were exposed to thermal aging (10,000 cycles, 5 to 55℃) and different surface treatment. All specimens were separated into 5 groups (n=15): 1) Intact specimens 2) Thermal aging-air polishing 3) Thermal aging- Er:YAG laser irradiation 4) Thermal aging- acid etching 5) Thermal-aging. All specimens were bonded to the zirconia discs with resin cement and fixed to universal testing machine and bond strength testing loaded to failure with a crosshead speed of 0.5 mm/min. The fractured surface was classified as adhesive failure, cohesive failure and adhesive-cohesive failure. The bond strength data was statistically compared by the Kruskal-Wallis method complemented by the Bonferroni correction Mann-Whitney U test. The probability level for statistical significance was set at α=.05. RESULTS Thermal aging and different surface treatment methods have significant effect on the bond strength between composite-resin cores and luting-agent (P<.05). The mean baseline bond strength values ranged between 7.07 ± 2.11 and 26.05 ± 6.53 N. The highest bond strength of 26.05 ± 6.53 N was obtained with Group 3. Group 5 showed the lowest value of bond strength. CONCLUSION Appropriate surface treatment method should be applied to aged composite resin cores or aged-composites restorations should be replaced for the optimal bond strength and the clinical success.

Is Biochemical Follow Up Possible in Peripheral Arterial Disease Treatment: Hypoxia Inducible Factor-1 Alpha?

Cihan Yücel,Mete Gürsoy,Serkan Ketenciler,Aslıhan Tenekeciğil,Feryaz Kızıltan,Nihan Kayalar 대한혈관외과학회 2021 Vascular Specialist International Vol.37 No.3

Purpose: The hypoxia inducible factor (HIF)-1 is a dimeric protein complex that plays an integral role in the body’s response to hypoxia. This study aimed to analyze the regulation of HIF-1α following vascular and/or endovascular surgery in peripheral arterial disease (PAD) patients. Materials and Methods: A total of 40 patients with PAD (≥Rutherford category 3) were included in this prospective study. The mean age was 61.9±9.2 years. Open surgery was performed in 16 patients, and endovascular intervention was performed in 34 patients. At preoperative (T1), postoperative day 1 (T2), and month 3 (T3), the serum HIF-1α levels were checked using the ELISA technique. Results: At T3, the ankle-brachial index was significantly higher than the preoperative value (P<0.001). Serum HIF-1α levels at T1, T2, and T3 were 2.0±1.7 ng/mL, 1.9±1.7 ng/mL, and 1.6±1.4 ng/mL, respectively. Serum HIF-1α levels between T1 and T3 and between T2 and T3 were significantly different (P<0.05). The preoperative HIF-1α levels were lowest in iliac lesions compared to femoropopliteal or tibial lesions. Conclusion: The HIF-1α levels were decreased in all patients on postoperative days, T2 and T3, compared with the preoperative values. Our results indicated that HIF-1α may be a surrogate marker after revascularization in patients with PAD. Further studies are needed to analyze the sensitivity, specificity, and cut-off values of HIF-1α in patients with PAD.

Evaluation of Paraoxonase, Arylesterase and Malondialdehyde Levels in Schizophrenia Patients Taking Typical, Atypical and Combined Antipsychotic Treatment

Mehmet Güneş,Mehmet Akif Camkurt,Mahmut Bulut,Süleyman Demir,Aslıhan Okan İbiloğlu,Mehmet Cemal Kaya,Abdullah Atlı,İbrahim Kaplan,Aytekin Sir 대한정신약물학회 2016 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.14 No.4

Objective: Human serum paraoxonase (PON1) prevents lipids from peroxidation and functions as an antioxidant mechanism. Malonyldialdehyde (MDA) is the final product of lipid peroxidation and can be used as an indicator of oxidative stress. The aim of this study was to investigate PON1, MDA, and arylesterase (ARY) levels in schizophrenic patients who are taking typical, atypical, or combined (typical and atypical) antipsychotic drug treatment, with respect to those of healthy controls. Methods: We evaluated 41 patients (11 taking typical antipsychotics, 19 taking atypical antipsychotics, 11 taking combined antipsychotics) and 43 healthy controls. Results: MDA levels were higher in schizophrenic patients taking typical antipsychotics compared with healthy controls (p=0.001). ARY levels were higher in patients taking atypical antipsychotics compared with healthy controls (p=0.005). PON1 activity was similar in all groups. Conclusion: Our results indicate that treatment with typical antipsychotic drugs could be related to increased MDA levels; and antipsychotic medication may increase PON1 levels in schizophrenic patients.