Incorporation of sporopollenin enhances acid–base durability, hydrophobicity, and mechanical, antifungal and antioxidant properties of chitosan films

Murat Kaya,Lalehan Akyuz,Idris Sargin,Muhammad Mujtaba,Asier M. Salaberria,Jalel Labidi,Yavuz S. Cakmak,Behlul Koc,Talat Baran,Talip Ceter 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.47 No.-

Sporopollenin-chitosan blendfilms were produced for thefirst time. Sporopollenin is a robust structuralcomponent of plant pollens exhibiting excellent features such as nontoxicity, biodegradability,biocompatibility, high thermal stability, durability to strong acid and base solutions and homogeneityin size. To benefit from these advantages, sporopollenin samples obtained from Betula pendula (silverbirch) were incorporated into chitosanfilm at different concentration; 10, 20 and 40 mg in 100 mLchitosan gel (1%). Stereo microscopy, FT-IR and TG/DTG analyses showed that sporopollenin wassuccessfully incorporated into the chitosan matrix. Incorporation of sporopollenin in gradually increasingamount into chitosanfilms was found advantageous in (1) enhancement in chemical durability of thefilms, (2) increment of hydrophobicity, (3) boosting the mechanical properties, (4) improvement ofantifungal and (5) antioxidant activities. This study revealed that sporopollenin can be suggested as aneffective blend material for biodegradable edible chitosanfilm production.

Extraction and Characterization of Chitin and Chitosan with Antimicrobial and Antioxidant Activities from Cosmopolitan Orthoptera Species (Insecta

Murat Kaya,Talat Baran,Meltem Asan-Ozusaglam,Yavuz Selim Cakmak,Kabil Ozcan Tozak,Abbas Mol,Ayfer Mentes,Goksal Sezen 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.1

This study examined two gregarious Orthopteraspecies (Calliptamus barbarus and Oedaleus decorus) aspotential sources of chitin. The chitin content of the dryweight of C. barbarus was 20.5 ± 0.7%, and it was 16.5 ±0.7% for O. decorus. Furthermore, the yield of chitosan (70~ 75% deacetylation degree) from the grasshopper specieswas found to be 74 ~ 76%, which is close to the yield ofcommercial preparations obtained from the unused parts ofcrabs and shrimp. The chitin and chitosan obtained in thisway were analyzed using FTIR, TGA, XRD and SEMtechniques, and the antimicrobial properties of chitosansobtained from C. barbarus and O. decorus against pathogenicmicroorganisms of humans and fish were investigatedusing the disc diffusion and microdilution broth methods. The antimicrobial screening procedures indicated that thechitosan showed significant antimicrobial activity againstall of the tested pathogenic microorganisms. The MBC orMFC values were determined to be 0.16 ~ 2.50 mg/mL. The IC50 values for the chitins obtained from C. barbarusand O. decorus were 10.68 ± 0.27 and 10.91 ± 0.96 mg/mL,respectively, which were greater than the value forbutylated hydroxytoluene (BHT): 0.04 ± 0.01 mg/mL. These results suggest that these two species, which arecurrently considered to be pests because of over-breeding,are potentially alternative sources of chitin and chitosan,which are used in the food/feed industry for theirantimicrobial and antioxidant properties.

Comparison of bovine serum albumin adsorption capacities of a-chitin isolated from an insect and b-chitin from cuttlebone

Murat Kaya,Idris Sargin,Volkan Aylanc,Muhammed Nebi Tomruk,Seda Gevrek,Isil Karatoprak,Nazlican Colak,Yasar Gul Sak,Esra Bulut 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.38 No.-

Bovine serum albumin is the key protein in blood. Chitin is a widely used biocompatible polymer inbioengineering and it is mainly found as two allomorphs (a, b). In this study the interactions of a-chitin(from the insect Omophlus sp.) and b-chitin (from the cuttlebone of Sepia sp.) with BSA were studied. Chitin isolates were examined by SEM, XRD, BET, TGA and FTIR. b-Chitin exhibited a far higher affinity forBSA than a-chitin, indicating a-chitin can be used in applications where surface–protein interactionsshould be limited, and b-chitin can be used in chitin-based materials on which protein adsorption isdesired.

New Chitin, Chitosan, and O-Carboxymethyl Chitosan Sources from Resting Eggs of Daphnia longispina (Crustacea); with Physicochemical Characterization, and Antimicrobial and Antioxidant Activities

Murat Kaya,Yavuz Selim Cakmak,Talat Baran,Meltem Asan-Ozusaglam,Ayfer Mentes,Kabil Ozcan Tozak 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.1

The paper describes the isolation and characterizationof chitin and chitosan from Daphnia longispinaresting eggs harvested from a reservoir. Resting eggs arefertilized eggs that are encased in chitinous shells called‘ephippia’ and which ensure the survival of the Daphniapopulation in adverse conditions. The chitin-content ofD. longispina resting eggs was found to be 23 ~ 25% andthe chitosan (having a 70 ~ 75% deacetylation degree)yield of the chitin was 76 ~ 77%. This high chitin-contentindicates that D. longispina resting eggs can be exploitedas a chitin source. The structure and thermal properties ofchitin, extracted from D. longispina resting eggs, werecharacterized by employing Fourier transform infraredspectroscopy, thermogravimetric analysis, X-ray diffractionand scanning electron microscopy. The crystallinity of thechitin was found to be very low (48%). Physicochemicallycharacterizedchitosan and the produced O-carboxymethylchitosan were tested for their antimicrobial and antioxidantactivity. It has been observed that chitosan displaysantimicrobial activity against all pathogenic bacteria, whereasO-carboxymethyl chitosan only exhibits inhibition activityagainst L. garvieae, L. Monocytogenes ATCC 7644, Y. enterocolitica NCTC 11175 and S. aureus ATCC 25923. Ina free radical scavenging activity assay, the IC50 values ofchitosan, O-carboxymethyl chitosan and butylated hydroxytoluenewere found to be 23.01, 56.43 and 0.05, respectively. The ferric-reducing power of O-carboxymethyl chitosan(EC50 = 8.30) indicated higher activity than chitosan (EC50= 10.12).

Nutritional properties, minerals, and selected heavy metal contents in herby cheese plants of Lamiaceae

Murat Tunc¸tu¨rk,Tamer Eryig˘it,Ali Rahmi Kaya 한국응용생명화학회 2017 Applied Biological Chemistry (Appl Biol Chem) Vol.60 No.1

Ten of the most popular and well-known edible plant species from the Lamiaceae which are used in the production of herby cheese were examined to evaluate their nutritional properties, mineral, and heavy metal content. This study has revealed significant variations in the contents of minerals among the studied plant species. The most of plant samples were rich in some of the vital minerals such as Fe, Cu, Ca, K, Mn, and Zn, which are known to be important in health maintenance. Ziziphora capitata plant materials had the highest concentration of toxic heavy metals, including chromium (1.72 mg kg-1), where Mentha longifolia had the highest cobalt (1.14 mg kg-1). The results of this study suggest that the use of these plant species in herby cheese will not contribute to heavy metal toxicity, but may be useful in treating micronutrient deficiency.

Primary Immunodeficiencies in Children Initially Admitted with Gastrointestinal/Liver Manifestations

Murat Cakir,Nalan Yakici,Elif Sag,Gulay Kaya,Ayşenur Bahadir,Alper Han Cebi,Fazil Orhan 대한소아소화기영양학회 2023 Pediatric gastroenterology, hepatology & nutrition Vol.26 No.4

Purpose: The gastrointestinal system is the most commonly affected organ, followed by the lungs, in patients with primary immunodeficiency disease (PID). Hence, it is common for children with PIDs to present with gastrointestinal symptoms. We aimed to analyze the clinical and histopathological findings of patients who were initially admitted to pediatric gastroenterology/hepatology clinics and subsequently diagnosed with PIDs to identify the clinical clues for PIDs. Methods: The demographic, laboratory, and histopathological findings, treatment modality, and outcomes of patients initially admitted to the pediatric gastroenterology/hepatology unit and subsequently diagnosed with PIDs were recorded. Results: The study included 24 patients (58.3% male; median age [range]: 29 [0.5–204] months). Common clinical presentations included chronic diarrhea (n=8), colitis (n=6), acute hepatitis (n=4), and acute liver failure (n=2). The association of autoimmune diseases, development of malignant diseases, and severe progression of viral diseases was observed in 20.8%, 8.3%, and 16.6% of the patients, respectively. Antibody deficiency was predominantly diagnosed in 29.2% of patients, combined immunodeficiency in 20.8%, immune dysregulation in 12.5%, defects in intrinsic and innate immunity in 4.2%, autoinflammatory disorders in 8.3%, and congenital defects of phagocytes in 4.2%. Five patients remained unclassified (20.8%). Conclusion: Patients with PIDs may initially experience gastrointestinal or liver problems. It is recommended that the association of autoimmune or malignant diseases or severe progression of viral diseases provide pediatric gastroenterologists some suspicion of PIDs. After screening using basic laboratory tests, genetic analysis is mandatory for a definitive diagnosis.

Experimental investigation of impact behaviour of shear deficient RC beam to column connection

Murat Aras,Tolga Yılmaz,Özlem Çalışkan,Özgür Anıl,R. Tuğrul Erdem,Turgut Kaya 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.5

Reinforced concrete (RC) structures may be subjected to sudden dynamic impact loads such as explosions occurring for different reasons, the collision of masses driven by rockfall, flood, landslide, and avalanche effect structural members, the crash of vehicles to the highway and seaway structures. Many analytical, numerical, and experimental studies focused on the behavior of RC structural elements such as columns, beams, and slabs under sudden dynamic impact loads. However, there is no comprehensive study on the behavior of the RC column-beam connections under the effect of sudden dynamic impact loads. For this purpose, an experimental study was performed to investigate the behavior of RC column-beam connections under the effect of low-velocity impact loads. Sixteen RC beam-column connections with a scale of 1/3 were manufactured and tested under impact load using the drop-weight test setup. The concrete compressive strength, shear reinforcement spacing in the beam, and input impact energy applied to test specimens were taken as experimental variables. The time histories of impact load acting on test specimens, accelerations, and displacements measured from the test specimens were recorded in experiments. Besides, shear and bending crack widths were measured. The effect of experimental variables on the impact behavior of RC beam-column connections has been determined and interpreted in detail. Besides, a finite element model has been established for verification and comparison of the experimental results by using ABAQUS software. It has been demonstrated that concrete strength, shear reinforcement ratio, and impact energy significantly affect the impact behavior of RC column-beam connections.

올리고피리디닐메틸렌아미노피리딘올과 금속 착화물의 합성, 분석 및 열분해 특성 연구

Ismet Kaya,Murat Gul 한국고분자학회 2008 폴리머 Vol.32 No.4

SARS-CoV-2 Antibodies in Children with Chronic Disease from a Pediatric Gastroenterology Outpatient Clinic

Gulay Kaya,Fatma Issi,Burcu Guven,Esra Ozkaya,Celal Kurtulus Buruk,Murat Cakir 대한소아소화기영양학회 2022 Pediatric gastroenterology, hepatology & nutrition Vol.25 No.5

Purpose: At the beginning of the Coronavirus disease (COVID-19) epidemic, physicians paid close attention to children with chronic diseases to prevent transmission or a severe course of infection. We aimed to measure the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody levels in children with chronic gastrointestinal and liver diseases to analyze the risk factors for infection and its interaction with their primary disease. Methods: This cross-sectional study analyzed SARS-CoV-2 antibody levels in patients with gastrointestinal and liver diseases (n=141) and in healthy children (n=48) between January and February 2021. Results: During the pandemic, 10 patients (7%) and 1 child (2%) had confirmed COVID-19 infection (p=0.2). The SARS-CoV-2 antibody test was positive in 36 patients (25.5%) and 11 children (22.9%) (p=0.7). SARS-CoV-2 antibody positivity was found in 20.4%, 26.6%, 33.3%, and 33.3% of patients with chronic liver diseases, chronic gastrointestinal tract diseases, cystic fibrosis, and liver transplantation recipients, respectively (p>0.05, patients vs. healthy children). Risk factors for SARS-CoV-2 antibody positivity were COVID-19-related symptoms (47.2% vs. 14.2%, p=0.00004) and close contact with SARS-CoV-2 polymerase chain reaction-positive patients (69.4% vs. 9%, p<0.00001). The use, number, and type of immunosuppressants and primary diagnosis were not associated with SARS-CoV-2 antibody positivity. The frequency of disease activation/flare was not significant in patients with (8.3%) or without (14.2%) antibody positivity (p=0.35). Conclusion: SARS-CoV-2 antibodies in children with chronic gastrointestinal and liver diseases are similar to that in healthy children. Close follow-up is important to understand the long-term effects of past COVID-19 infection in these children.

Butterfly Cartilage Tympanoplasty Long-term Results: Excellent Treatment Method in Small and Medium Sized Perforations

Isa Kaya,Murat Benzer,Mustafa Uslu,Cem Bilgen,Tayfun Kirazli 대한이비인후과학회 2018 Clinical and Experimental Otorhinolaryngology Vol.11 No.1

Objectives. The aim of this study was to evaluate and report the long-term results of the butterfly cartilage tympanoplasty. Short-term and long-term hearing outcomes were compared according to age and perforation location as well. Methods. Ninety-three patients who were diagnosed with noncomplicated chronic otitis media and underwent microscopic transcanal butterfly cartilage tympanoplasty due to anterior, posterior, and central tympanic membrane perforation were included. Age, gender, follow-up time, pre- and postoperative pure tone audiometry thresholds (both air and bone conduction), pre- and postoperative air-bone gaps (ABGs), if any residual perforation was noted. Results. At the end of the follow-up period, successful closure occurred in 88 of 93 patients and success rate is 94.6%. In all patients, including those with residual perforations, the mean preoperative bone conduction threshold was 15.9 dB (range, 5 to 50 dB) among all groups whereas mean air conduction threshold was 36.4±15.1 dB (range, 10 to 90 dB) preoperatively and 28.8±14.3 dB in 6th month follow-up and 24.9±14.1 dB 24th month follow-up. Preoperative mean ABG was 22.1±7.1 dB (range, 5 to 40 dB) whereas 13.3±5.9 dB 6 months after surgery and 11.9±5.5 dB 24 months after surgery. There was a significant difference between pre- and postoperative ABG in both 6th and 24th month follow-up (P6 mo–24 mo<0.05). Furthermore, preoperative mean air conduction differed significantly from postoperative 6th and 24th month follow-up mean air conduction thresholds (P<0.05). Conclusion. We suggested that butterfly cartilage tympanoplasty can be safely performed in small, moderate, and even large perforations, as the hearing outcomes and successful closure rate are similar to those of other surgical methods. Moreover, it can be performed under local anaesthesia and it has low complication rates.