Microstructure characterization and mechanical properties of Cr-Ni/ZrO₂ nanocomposites

Sevinc, O zlem,Diler, Ege A. Techno-Press 2022 Advances in nano research Vol.13 No.4

The microstructure and mechanical properties of Cr-Ni steel and Cr-Ni steel-matrix nanocomposites reinforced with nano-ZrO₂ particles were investigated in this study. Cr-Ni steel and Cr-Ni/ZrO₂ nanocomposites were produced using a combination of high-energy ball milling, pressing, and sintering processes. The microstructures of the specimens were analyzed using EDX and XRD. Compression and hardness tests were performed to determine the mechanical properties of the specimens. Nano-ZrO₂ particles were effective in preventing chrome carbide precipitate at the grain boundaries. While t-ZrO₂ was detected in Cr-Ni/ZrO₂ nanocomposites, m-ZrO₂ could not be found. Few α'-martensite and deformation bands were formed in the microstructures of Cr-Ni/ZrO₂ nanocomposites. Although nano-ZrO₂ particles had a negligible impact on the strength improvement provided by deformation-induced plasticity mechanisms in Cr-Ni/ZrO₂ nanocomposites, the mechanical properties of Cr-Ni steel were significantly improved by using nano-ZrO₂ particles. The hardness and compressive strength of Cr-Ni/ZrO₂ nanocomposite were higher than those of Cr-Ni steel and enhanced as the weight fraction of nano-ZrO₂ particles increased. Cr-Ni/ZrO₂ nanocomposite with 5wt.% nano-ZrO₂ particles had almost twofold the hardness and compressive strength of Cr-Ni steel. The nano-ZrO₂ particles were considerably more effective on particle-strengthening mechanisms than deformation-induced strengthening mechanisms in Cr-Ni/ZrO₂ nanocomposites.

LaeA Control of Velvet Family Regulatory Proteins for Light-Dependent Development and Fungal Cell-Type Specificity

Sarikaya Bayram, Ö,zlem,Bayram, Ö,zgü,r,Valerius, Oliver,Park, Hee Soo,Irniger, Stefan,Gerke, Jennifer,Ni, Min,Han, Kap-Hoon,Yu, Jae-Hyuk,Braus, Gerhard H. Public Library of Science 2010 PLoS genetics Vol.6 No.12

<▼1><P>VeA is the founding member of the velvet superfamily of fungal regulatory proteins. This protein is involved in light response and coordinates sexual reproduction and secondary metabolism in <I>Aspergillus nidulans</I>. In the dark, VeA bridges VelB and LaeA to form the VelB-VeA-LaeA (velvet) complex. The VeA-like protein VelB is another developmental regulator, and LaeA has been known as global regulator of secondary metabolism. In this study, we show that VelB forms a second light-regulated developmental complex together with VosA, another member of the velvet family, which represses asexual development. LaeA plays a key role, not only in secondary metabolism, but also in directing formation of the VelB-VosA and VelB-VeA-LaeA complexes. LaeA controls VeA modification and protein levels and possesses additional developmental functions. The <I>laeA</I> null mutant results in constitutive sexual differentiation, indicating that LaeA plays a pivotal role in inhibiting sexual development in response to light. Moreover, the absence of LaeA results in the formation of significantly smaller fruiting bodies. This is due to the lack of a specific globose cell type (Hülle cells), which nurse the young fruiting body during development. This suggests that LaeA controls Hülle cells. In summary, LaeA plays a dynamic role in fungal morphological and chemical development, and it controls expression, interactions, and modification of the velvet regulators.</P></▼1><▼2><P><B>Author Summary</B></P><P>Numerous fungi have the potential to infect immunocompromised patients or to contaminate and spoil our nutrients. They represent an increasing danger that threatens public health and agriculture. This requires improved understanding of fungal growth, development, dissemination of spores, and mycotoxin production. We have discovered two related fungal specific protein complexes that provide a molecular link among spore formation, fungal development, and secondary metabolite production. The subunit allocation of both complexes depends on each other, and they share a common subunit. These complexes comprise three related and in fungi conserved proteins of the velvet family that function in concert with a known regulator of secondary metabolism, LaeA. This protein controls the formation of both complexes but is only a part of the trimeric complex. We found that this regulator of secondary metabolism also possesses several developmental control functions in gene expression. These protein complexes discovered in the fungal model system <I>Aspergillus nidulans</I> are conserved in fungal pathogens where they might provide novel insights for understanding growth, development, and interaction with their respective hosts.</P></▼2>

Increased Serum Level of CCL5 in Children with Attention‑Deficit/Hyperactivity Disorder: First Results about Serum Chemokines

Ahmet Ö,zaslan,Esra Gü,ney,Ö,zlem Gü,lbahar,Dicle Bü,yü,ktaskin,Burak Arslan 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.1

Objective: Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder and its aetiology is not fully understood. This study aimed to determine whether the CCL5 and CCL11 influence the ADHD aetiology by comparing serum CCL5 and CCL11 levels of children with ADHD and typical development. Methods: This study included 45 (27 males, mean age = 8.9 ± 1.7 years) treatment-naive patients diagnosed with ADHD and 35 (20 males, mean age = 8.8 ± 1.6 years) healthy controls. Participants ranged in age between 6−12 years and completed the Conners Teacher Rating Scale that assesses ADHD presentation and severity. CCL5 and CCL11 serum levels were also measured using enzyme-linked immunosorbent assay kits. Results: Significantly higher serum CCL5 levels were found in children with ADHD compared to healthy controls (p < 0.001). No significant difference was found between the mean serum CC11 level of the patients and controls (p = 0.93). In addition, there was no significant correlation between the serum CCL5 and CCL11 levels and predominant presentations of ADHD and disease severity. Conclusion: This study suggests that there are higher levels of serum CCL5 in drug naive children with ADHD, this findings suggest that CCL5 might play a role in the pathophysiology of ADHD. Moreover, these changes in peripheral blood may have therapeutic value. In addition, these results help to understand the role of chemokines in elucidating the etiopathogenesis of ADHD. Our results can be considered as the first step in investigating the role of CCL5 in ADHD, and further research is needed to support these initial findings.

Investigation of the Usability of Retrograded Flour in Meatball Production as A Structure Enhancer

Elif Aykin Dinç,er,Ö,zlem Kiliç,Bü,yü,kkurt,Cihadiye Candal,Bü,ş,ra Fatma Bilgiç,Mustafa Erbaş 한국축산식품학회 2018 한국축산식품학회지 Vol.38 No.1

This study aimed to research the possibilities of using retrograded flour produced in the laboratory environment in meatballs and the characteristics of these meatballs. In the use of retrograded flour to produce meatballs, it was ensured that the meatball properties, with respect to chemical, physical and sensorial aspects, were comparable to those of meatballs produced with bread (traditional) and rusk flour (commercial). The cooking loss of meatballs produced with using retrograded flour was similar to that of commercial meatballs. Doses of retrograded flour from 5% to 20% led to a significant decrease in cooking loss, from 21.95% to 6.19%, and in the diameter of meatballs, from 18.60% to 12.74%, but to an increase in the thickness of meatballs, from 28.82% to 41.39% compared to the control. The increase of a* and b* values was shown in that the meatballs were browned on cooking with increasing retrograded flour doses because of non-enzymatic reactions. The springiness of the traditional meatballs was significantly higher than that of the other meatballs. This might have been due to the bread crumbs having a naturally springy structure. Moreover, the addition of retrograded flour in the meatballs significantly (p<0.05) affected the hardness, springiness and cohesiveness of the meatballs with respect to textural properties. Accordingly, it is considered that the use of 10% retrograded flour is ideal to improve the sensorial values of meatballs and the properties of their structure.

<i>Porphyromonas gingivalis</i> traffics into endoplasmic reticulum-rich-autophagosomes for successful survival in human gingival epithelial cells

Lee, Kyulim,Roberts, JoAnn S.,Choi, Chul Hee,Atanasova, Kalina R.,Yilmaz, Ö,zlem TaylorFrancis 2018 Virulence Vol.9 No.1

<P><B>ABSTRACT</B></P><P><I>Porphyromonas gingivalis</I>, an opportunistic pathogen usurps gingival epithelial cells (GECs) as primary intracellular niche for its colonization in the oral mucosa. However, the precise characterization of the intracellular trafficking and fate of <I>P. gingivalis</I> in GECs remains incomplete. Therefore, we employed high-resolution three-dimensional-transmission-electron-microscopy to determine the subcellular location of <I>P. gingivalis</I> in human primary GECs upon invasion. Serial sections of infected-GECs and their tomographic reconstruction depicted ER-rich-double-membrane autophagosomal-vacuoles harboring <I>P. gingivalis</I>. Western-blotting and fluorescence confocal microscopy showed that <I>P. gingivalis</I> significantly induces LC3-lipidation in a time-dependent-manner and co-localizes with LC3, ER-lumen-protein Bip, or ER-tracker, which are major components of the phagophore membrane. Furthermore, GECs that were infected with FMN-green-fluorescent transformant-strain (PgFbFP) and selectively permeabilized by digitonin showed rapidly increasing large numbers of double-membrane-vacuolar-<I>P. gingivalis</I> over 24 hours of infection with a low-ratio of cytosolically free-bacteria. Moreover, inhibition of autophagy using 3-methyladenine or ATG5 siRNA significantly reduced the viability of intracellular <I>P. gingivalis</I> in GECs as determined by an antibiotic-protection-assay. Lysosomal marker, LAMP-1, showed a low-degree colocalization with <I>P. gingivalis</I> (∼20%). PgFbFP was used to investigate the fate of vacuolar- versus cytosolic-<I>P. gingivalis</I> by their association with ubiquitin-binding-adaptor-proteins, NDP52 and p62. Only cytosolic-<I>P. gingivalis</I> had a significant association with both markers, which suggests cytosolically-free bacteria are likely destined to the lysosomal-degradation pathway whereas the vacuolar-<I>P. gingivalis</I> survives. Therefore, the results reveal a novel mechanism for <I>P. gingivalis</I> survival in GECs by harnessing host autophagy machinery to establish a successful replicative niche and persistence in the oral mucosa.</P>

Move over? Feminist reading of academic writing on Kurdish women

Özlem Belçim Galip 이화여자대학교 한국여성연구원 2021 Asian Journal of Women's Studies(AJWS) Vol.27 No.4

Research on Kurdish women has burgeoned during the last decade, which is a positive sign of the growing interest regarding a highly marginalized population and region. However, most of these works contain theoretical and methodological inadequacies, fallacies and contradictory messages regarding the agency, or lack of it, of Kurdish women, along with an orientalist approach. Using feminist rhetorical criticism and discourse approaches, together with a focus on intersectionality, orientalism and postcolonial feminism, I examine some existing studies on Kurdish women and attempt to uncover the construction of and implications about Kurdish women. I also examine the degrees to which these studies promote narratives that uphold assumptions on gender and implicitly contribute to traditional ideologies of patriarchy and the stigma of being westernized. By demonstrating the significance of a plural model, which examines the lived realities of women, their negotiations and struggles, I urge a fresh approach to the discursive and contextual practice of scholarship on Kurdish women.

Probabilistic sensitivity analysis of suspension bridges to near-fault ground motion

Özlem Çavdar 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.1

The sensitivities of a structural response due to variation of its design parameters are prerequisite in the majority of the algorithms used for fundamental problems in engineering as system uncertainties, identification and probabilistic assessments etc. The paper presents the concept of probabilistic sensitivity of suspension bridges with respect to near-fault ground motion. In near field earthquake ground motions, large amplitude spectral accelerations can occur at long periods where many suspension bridges have significant structural response modes. Two different types of suspension bridges, which are Bosporus and Humber bridges, are selected to investigate the near-fault ground motion effects on suspension bridges random response sensitivity analysis. The modulus of elasticity is selected as random design variable. Strong ground motion records of Kocaeli, Northridge and Erzincan earthquakes are selected for the analyses. The stochastic sensitivity displacements and internal forces are determined by using the stochastic sensitivity finite element method and Monte Carlo simulation method. The stochastic sensitivity displacements and responses obtained from the two different suspension bridges subjected to these near-fault strong-ground motions are compared with each other. It is seen from the results that near-fault ground motions have different impacts stochastic sensitivity responses of suspension bridges. The stochastic sensitivity information provides a deeper insight into the structural design and it can be used as a basis for decision-making.

Barbed sutures versus conventional tenorrhaphy in flexor tendon repair: An ex vivo biomechanical analysis

Özlem Çolak Aslan,Yüksel Kankaya,Nezih Sungur,Kadri Özer,Koray Gürsoy,Kemal Şerbetçi,Uğur Koçer 대한성형외과학회 2019 Archives of Plastic Surgery Vol.46 No.3

Background The management of flexor tendon injuries has evolved in recent years through industrial improvements in suture materials, refinements of repair methods, and early rehabilitation protocols. However, there is no consensus on the ideal suture material and technique. This study was conducted to compare the tensile strength, repair time, and characteristics of 4-strand cruciate, modified Kessler, and 4-strand horizontal intrafiber barbed sutures for flexor tenorrhaphy with a 12-mm suture purchase length in an animal model. Methods The right third deep flexors of 60 adult Leghorn chicken feet were isolated and repaired with a 12-mm suture purchase length. The tendons were randomly assigned to three groups of equal number (n=20 each). Groups 1 and 2 received 4-strand cruciate and modified Kessler repair with conventional suture materials, respectively. A 4-strand horizontal intrafiber barbed suture technique was used in group 3. The repaired tendons were biomechanically tested for tensile strength, 2-mm gap resistance, and mode of failure. Repair times were also recorded. Results The maximum tensile strength until failure was 44.6±4.3 N in group 1, 35.7±5.2 N in group 2, and 56.7±17.3 N in group 3. The barbed sutures were superior to the other sutures in terms of the load needed for 2-mm gap formation (P<0.05). Furthermore, the barbed sutures showed the shortest repair time (P<0.05). Conclusions This study found that 4-strand horizontal intrafiber barbed suture repair with a 12-mm purchase length in a chicken flexor tendon injury model showed promising biomechanical properties and took less time to perform than other options.

An Integrated Methodology for the Conservation of Traditional Craftmanship in Historic Buildings

Özlem Karakul 국립민속박물관 2015 International Journal of Intangible Heritage Vol.10 No.-

The aim of conservation is to sustain both the physical andintangible aspects of historical buildings and to transferthem to the future. Conservation needs to consider theintangible aspects of historic buildings as well as theirphysical and visible characteristics. It is as important toconserve and document traditional craftsmanship, theknow-how, techniques and skills of the builders, as it is topreserve traditional architecture. Traditional craftsmanshipis one of the domains of intangible cultural heritage to besafeguarded as defined in the UNESCO 2003 Convention. Inthe field of architecture, traditional craftsmanship isespecially embodied in construction techniques andarchitectural ornamentation in historic buildings. As with the physical and architectural features of historicbuildings, the means of safeguarding of their intangibleaspects needs to be transmitted to the next generation. Historically, the transmission process used to be through themaster-apprentice relationship. Nowadays, together withthe loss of traditional building methods and drastic changesin building technology, the knowledge and skills of localbuilders and the related cultural expressions have beenvirtually forgotten by the present generation. This studytherefore proposes an integrated conservation methodologyto re-constitute master-apprentice relationships for thesustainability of traditional craftsmanship, considering boththe intangible and tangible aspects. Such a methodologyincludes both the documentation of physical structures andof the related cultural expressions, the practising andtransferring of the knowledge of building methods and theskills and techniques of builders to a new generation. Thismethodology is illustrated by means of a workshop whichwas organised in the Fine Arts Faculty in Selçuk Universityfor one week in May 2013 which focused on theintergenerational transmission of the skills of ‘living humantreasures’ of traditional architecture.

Integration of PET/CT in Current Diagnostic and Response Evaluation Methods in Patients with Tuberculosis

Özlem Özmen,Ebru Tatcı,İnci Biner,Behiye Akkalyoncu 대한핵의학회 2014 핵의학 분자영상 Vol.48 No.1

Tuberculosis is a systemic disease that still affectsmany people. While pleural involvement is frequently observedin extrapulmonary tuberculosis, multiple skeletal systemand articular involvements are quite rare. FDG PETimaging could be a promising diagnostic and treatment monitoringmethod, especially in complicated cases and if theother methods are inadequate. In this case study, we report apatientwho was admittedwith suspected malignancy and thendiagnosed with tuberculosis pleuritis, lymphadenitis,spondylodiscitis, and sacroiliitis with specific symptoms; theresponse to anti-tuberculosis therapy was shown using FDGPET/CT.