WoS İndeksli Yayınlar / WoS Indexed Publications

Permanent URI for this collectionhttps://hdl.handle.net/11413/6359

Browse

Now showing 1 - 20 of 177

Open Access
Ameliyat Sonrası Akut Ağrı Yoğunluğunun Değerlendirilmesinde Dört Farklı Ağrı Ölçeğinin Karşılaştırılması
(Çukurova Üniversitesi, 2020) Gürkan, Aysel; Aldemir, Kadriye; Andsoy, Işıl Işık; GÜL, ASİYE
Amaç: Bu çalışmada yaşlılar da dahil yetişkinlerde yaygınkullanılan Görsel Analog, Numerik Orantılama, Sözel Tanımlayıcı ve Yüz Ağrı ölçekleri arasındaki uyum düzeyinive hasta tercihlerini karşılaştırmak amacıyla yapılmıştır. Gereç ve Yöntem: Çalışma 17 Mart - 17 Haziran 2016tarihleri arasında bir üniversite hastanesinin cerrahikliniklerinde tanımlayıcı araştırma modeli kullanılarak yapıldı. Bu çalışmaya her grupta 40 kişi olmak üzere toplam 120 yetişkin hasta çalışmaya alındı. Verilerin toplanmasında bireysel özellikler formu, Görsel Analog Ölçeği, Numerik Orantılama Ölçeği, Sözel Tanımlayıcı Ölçek ve Yüz Ağrı Ölçekleri kullanıldı. Bulgular: Bu çalışmada 0,71 – 0,83 arasında değişen korelasyon katsayıları ile dört ağrı ölçeğinin birbirleriyle iyi bir uyum içinde olduğu bulundu. Numerik Orantılama Ölçeği, tüm hastalar tarafından kullanılması en basit ve gelecekte kullanılması en fazla tercih edilen ve en az hata oranına sahip ölçek olurken Görsel Analog Ölçeği hastalar tarafından en az basit bulunan ve en az tercih edilen, en fazla hata oranına sahip ölçek olduğu saptandı. Genç ve orta yaş grubu hastalar tarafından kullanılması en basit ve fazla tercih edilen ölçek Numerik Orantılama Ölçeği seçilirken, yaşlılar tarafından Sözel Tanımlayıcı Ölçek seçildi. Sonuç: Postoperatif akut ağrı yoğunluğunun değerlendirilmesinde dört ölçeğin birbirleri ile iyi bir uyum içinde olduğu, Numerik Orantılama Ölçeği’nin ilk, Sözel Tanımlayıcı Ölçeğin ikinci tercih olarak seçilmesi ve Görsel Analog Ölçeği’nin ise son seçenek olduğu sonucu çıkarılabilir.
Open Access
An Analysis of Differential Bundle Functioning in Multidimensional Tests Using the SIBTEST Procedure
(Jate-Int Journal Assessment Tools Education, 2022) ÖZDOĞAN, DİDEM; Kelecioğlu, Hülya
This study aims to analyze the differential bundle functioning in multi-dimensional tests with a specific purpose to detect this effect through differentiating the location of the item with dif in the test, the correlation between the dimensions, the sample size, and the ratio of reference to focal group size. The first 10 items of the test that is comprised of 30 items were acknowledged as the bundle. The data in line with the parameters were generated via sas program as two categories (1-0) and multidimensional through an extended 2pl model. Differential bundle functioning was detected via the sibtest procedure. The results of the study were interpreted according to the criteria of the power rate and the type I error. When the results were reviewed, the analysis of the bundle revealed that the more the correlation between the two dimensions increased, relatively the less the power rates became. It was observed that the power rates, which were obtained according to two different sample sizes in the study, increased as the sample size increased. Another result as to the sibtest's power for detecting dif was the highest when the ratio of reference to focal group size was equal. According to the results of the type I error rate, the error rate was observed to be relatively decreasing as the correlation between the dimensions increased and it was observed to be increasing as the sample size increased. Also, the highest error rate was obtained when the ratio of the samples was equal.
Open Access
An Efficient Generation and Security Analysis of Substitution Box Using Fingerprint Patterns
(IEEE, 2020) ŞENGEL, ÖZNUR; Aydın, Muhammed Ali; Sertbaş, Ahmet
Information and its security have attracted the research community in recent years with increasing usage of mobile applications. Mobile devices have different security options in data transmission such as reading some biometric values. The keystone of the modern block and stream ciphers is the use of a substitution box (s-box) that obscures correlation between plaintext and ciphertext. In this study, we proposed a novel s-box generation algorithm by using the fingerprint pattern of the person who transfers information to the target. We generated several s-boxes by using bifurcation and ridge ending features of the fingerprint. Proposed s-boxes are compared with several known s-boxes over nonlinearity, bijectiveness, strict avalanche criterion, bit independence criterion, linear probability, and differential probability. Along with these properties, we analyzed confidence interval and randomness properties of new s-boxes as well. Also, the execution time of the proposed s-box generation algorithm is calculated and examined. The results of the cryptographic properties have shown that the proposed s-boxes by using ridge ending of the fingerprint performs better. The performances analysis show that the proposed s-box has satisfactory results according to the results of chaotic-based s-boxes. On the other hand, the fingerprint s-boxes are much better than the existing biometric s-boxes according to the s-box security metrics. The results have shown that the execution time of the proposed s-box generation algorithm is more minimum than the existing biometric s-box generation algorithms. Resulting from applying fingerprint biometric data to generate an s-box, such a successful algorithm is promising to be used in mobile devices.
Open Access
An Evaluation of Liminality in Nadine Gordimer's July's People
(2020-03) KABAK, MURAT
Set during a civil war in the apartheid South Africa, Nadine Gordimer's July's People is centred around the relationship between the Smales family and their former servant July. As the communal ties disintegrate in the novel, three objects play a vital role in our understanding of the characters. For the purposes of this study, these symbols not only help us to reveal the nature of spatial-temporal dislocation but also reveal Gordimer's commentary on the apartheid South Africa. This study aims to contribute the existing scholarship by focusing on the liminal/in-between experience in July's People through analyzing the novel's preoccupation with subject-object relationship.
Open Access
Analysis of a Prefabricated Vertical Drain (PVD) Soil Improvement Project
(Turkish Chamber Civil Engineers, 2022) MERT, AHMET CAN; AREL, ERSİN; ÖNALP, AKIN
A settlement analysis has been carried out for several sectors of a rail station yard improved with prefabricated vertical drains (PVD) in Istanbul, that exhibited prolonged consolidation beyond the predicted values in certain sectors of the treated zone. Final settlement and End of Primary (EOP) settlement times have been estimated theoretically as well as using the Asaoka graphical procedure. The compliance of settlement-time curves with in-situ measurements and Asaoka solution has been investigated. A geotechnical model was developed for finite element and three-dimensional consolidation analyses. The settlement curves obtained by varying horizontal-vertical permeability coefficient ratio (k(h)/k(v)) and in-situ measurements have been compared, and k(h)/k(v) values corresponding to 90% degree of consolidation has been computed for all sectors. The effect of drain spacing (S-drain) as well as drain length (L-drain) on the rate of consolidation have been evaluated for each sector, keeping the specified ratios constant. The times corresponding to 95% degree of consolidation (t(95)) have been calculated using the theoretical solution and compared to in-situ measurements. Calculated t(95)'s has also been compared to their estimated values by varying the spacing (S-drain) and the length (L-drain). Additionally, the required intervals of S-drain and L-drain have been obtained corresponding to the calculated t(95) times. The analyses suggest that the main reason for prolonged consolidation was the horizontal to vertical permeability coefficient ratio. According to the analysis results, PVD implementation was not efficient in clays having k(h)/k(v) of approximately unity. The main conclusion of this study was to discover the necessity for optimizing the variables in any such project. The efficacy of the works can be significantly enhanced if simultaneous evaluation of the parameters S-drain and L-drain and the permeability ratio k(h)/k(v) is carried out prior to field work. Otherwise, "accidents" may emerge as found out in this project.
Open Access
Are There Any Changes in Mothers' Attitudes? Analysis of the Impact of the Covid-19 Quarantine on Child-Rearing Attitudes
(Pergamon-Elsevier Science Ltd., 2022) TORAN, MEHMET; Özden, Bülent
The present study aims to examine the impact of the time spent by mothers at home with their children during the quarantine period that was implemented due to the COVID-19 pandemic on the mothers' child-rearing attitudes, taking into consideration some variables and the experiences of mothers. The study was designed using embedded mixed design, in which qualitative and quantitative research methods were used together. The quantitative research group consisted of 673 mothers and the qualitative research group consisted of 16 mothers. The research data was gathered online using the Lime Survey platform, and the interviews with the mothers were also held online. Demographic information form, the Child Rearing Attitude Scale, and a semi-structured interview form were used as data collection tools. Moderator variable analysis was used for the quantitative research data and descriptive analysis was used for the qualitative research data in support of the quantitative data. The findings revealed that the mothers' child-rearing attitudes changed depending on the variables concerning the children; however, the quarantine period instituted due to COVID-19 had an impact on the mothers' child-rearing attitudes depending on the variables of age and number of children. The qualitative findings obtained from the interviews supported the quantitative findings. However, it was revealed that the mothers' attitudes towards their children underwent changes during the quarantine period under COVID-19.
Open Access
Are Time Management and Cyberloafing Related? Investigating Employees’ Attitudes
(2020) Ötken, A. Begüm; Bayram, Ayhan; Göl Beşer, Senem; KAYA, ÇİĞDEM; 246912; 108211; 18140
Time is a critical commodity both for individuals and companies because it is not possible to substitute or purchase it. The concept of time management, therefore, attracted the attention of both academicians and practitioners. Companies started to question behaviour of employees using their companies’ Internet access for non-work-related purposes during work hours. These activities constitute an unproductive use of time and detract employees from completing their work demands. In this framework, the purpose of this study is to understand whether time management and cyberloafing are related. Data were collected from 300 employees working in Istanbul, Turkey. Results show that the time wasters dimension negatively explained the variance in serious cyberloafing. Results also show that time planning and time attitude dimensions positively explained the variance in minor cyberloafing. Understanding the relationship between time management and cyberloafing provides fruitful results for companies and individuals in terms of productivity and achieving goals at work.
Open Access
Atiprimod Triggered Apoptotic Cell Death Via Acting on PERK/eIF2 alpha/ATF4/CHOP and STAT3/NF-Kappa B axis in MDA-MB-231 and MDA-MB-468 Breast Cancer Cells
(Springer, 2021) Çoker-Gürkan, Ajda; CAN, ESİN; ŞAHİN, SEMANUR; ARISAN, ELİF DAMLA; YERLİKAYA, PINAR OBAKAN
Purpose The constitutive activation of STAT3 through receptor tyrosine kinases triggered breast cancer cell growth and invasion-metastasis. Atiprimod impacts anti-proliferative, anti-carcinogenic effects in hepatocellular carcinoma, lymphoma, multiple myeloma via hindering the biological activity of STAT3. Dose-dependent atiprimod evokes first autophagy as a survival mechanism and then apoptosis due to prolonged ER stress in pituitary adenoma cells. The therapeutic efficiency and mechanistic action of atiprimod in breast cancer cells have not been investigated yet. Thus, we aimed to modulate the pivotal role of ER stress in atiprimod-triggered apoptosis in MDA-MB-231 and MDA-MB-468 breast cancer cells. Results Dose- and time-dependent atiprimod treatment inhibits cell viability and colony formation in MDA-MB-468 and MDA-MB-231 breast cancer cells. A moderate dose of atiprimod (2 mu M) inhibited STAT3 phosphorylation at Tyr705 residue and also suppressed the total expression level of p65. In addition, nuclear localization of STAT1, 3, and NF-kappa B was prevented by atiprimod exposure in MDA-MB-231 and MDA-MB-468 cells. Atiprimod evokes PERK, BiP, ATF-4, CHOP upregulation, and PERK (Thr980), eIF2 alpha (Ser51) phosphorylation's. However, atiprimod suppressed IRE1 alpha-mediated Atg-3, 5, 7, 12 protein expressions and no alteration was observed on Beclin-1, p62 expression levels. PERK/eIF2 alpha/ATF4/CHOP axis pivotal role in atiprimod-mediated G1/S arrest and apoptosis via Bak, Bax, Bim, and PUMA upregulation in MDA-MB-468 cells. Moreover, atiprimod renders MDA-MB-231 more vulnerable to type I programmed cell death by plasmid-mediated increased STAT3 expression. Conclusion Atiprimod induced prolonged ER stress-mediated apoptosis via both activating PERK/eIF2 alpha/ATF4/CHOP axis and suppressing STAT3/NF-kappa B transcription factors nuclear migration in TBNC cells.
Open Access
Benchmarking the Anisotropy of Nitroxyl Radical Solvation With IR Spectroscopy
(The Royal Society of Chemistry, 2024) Bras, Elisa M.; Zimmermann, Charlotte; FAUSTO, RUI; Suhm, Martin A.
Two simple nitroxyl radicals, di-tert-butyl nitroxyl (DTBN) and 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) are solvated by one or two water, methanol, tert-butyl alcohol or phenol molecules. The resulting low temperature IR spectra of the vacuum-isolated microsolvates in the OH stretching range are assigned based on harmonic DFT predictions for closed shell solvent dimers and trimers and their offset from experiment, to minimise theory-guided assignment bias. Systematic conformational preferences for the first and second solvent molecule are observed, depending on the conformational rigidity of the radical. These assignments are collected into an experimental benchmark data set and used to assess the spectral predicting power of different DFT approaches. The goal is to find inexpensive computational methods which provide reliable spectral predictions for this poorly explored class of microsolvates.
Open Access
Biochemical and Proteomic Analyses in Drought-Tolerant Wheat Mutants Obtained by Gamma Irradiation
(MDPI, 2024) Şen, Ayşe; GÜMÜŞ, TAMER; Temel, Aslıhan; Öztürk, İrfan; ÇELİK, ÖZGE
The bread wheat cultivar (Triticum aestivum L. cv. Sagittario) as a parental line and its mutant, drought-tolerant lines (Mutant lines 4 and 5) were subjected to polyethylene glycol (PEG)-induced drought. Drought stress resulted in decreased chlorophyll levels and the accumulation of proline and TBARS, despite increases in activities of catalase, peroxidase, and superoxide dismutase enzymes. Transcription of the genes encoding these enzymes and delta-1-pyrroline 5-carboxylase synthetase was induced by drought. 2-DE gel electrophoresis analysis identified differentially expressed proteins (DEPs) in the mutant lines, which are distinguished by "chloroplast", "mitochondrion", "pyruvate dehydrogenase complex", and "homeostatic process" terms. The drought tolerance of the mutant lines might be attributed to improved photosynthesis, efficient ATP synthesis, and modified antioxidant capacity. In addition to proteomics data, the drought tolerance of wheat genotypes might also be assessed by chlorophyll content and TaPOX gene expression. To our knowledge, this is the first proteomic analysis of gamma-induced mutants of bread wheat. These findings are expected to be utilized in plant breeding studies.
Open Access
Biosignals, Facial Expressions, and Speech as Measures of Workplace Stress: Workstress3d Dataset
(Elsevier, 2024) Doğan, Gülin; AKBULUT, FATMA PATLAR; Çatal, Çağatay
WorkStress3D is a comprehensive collection of multimodal data for the research of stress in the workplace. This dataset contains biosignals, facial expressions, and speech signals, making it an invaluable resource for stress analysis and related studies. The ecological validity of the dataset was ensured by the fact that the data were collected in actual workplace environments. The biosignal data contains measurements of electrodermal activity, blood volume pressure, and cutaneous temperature, among others. High-resolution video recordings were used to capture facial expressions, allowing for a comprehensive analysis of facial cues associated with tension. In order to capture vocal characteristics indicative of tension, speech signals were recorded. The dataset contains samples from both stress-free and stressful work situations, providing a proportionate representation of various stress levels. The dataset is accompanied by extensive metadata and annotations, which facilitate in-depth analysis and interpretation. WorkStress3D is a valuable resource for developing and evaluating stress detection models, examining the impact of work environments on stress levels, and exploring the potential of multimodal data fusion for stress analysis.
Open Access
Blockchain-Based KYC Model for Credit Allocation in Banking
(IEEE-Inst Electrical Electronics Engineers Inc., 2024) Karadağ, Bulut; Zaim, A. Halim; AKBULUT, AKHAN
The implementation of the Know Your Customer (KYC) strategy by banks within the financial sector enhances the operational efficiency of such establishments. The data gathered from the client during the KYC procedure may be applied to deter possible fraudulent activities, money laundering, and other criminal undertakings. The majority of financial institutions implement their own KYC procedures. Furthermore, a centralized system permits collaboration and operation execution by multiple financial institutions. Aside from these two scenarios, KYC processes can also be executed via a blockchain-based system. The blockchain's decentralized network would be highly transparent, facilitating the validation and verification of customer data in real-time for all relevant stakeholders. In addition, the immutability and cryptography of the blockchain ensure that client information is secure and immutable, thereby eradicating the risk of data breaches. Blockchain-based KYC can further improve the client experience by eliminating the requirement for redundant paperwork and document submissions. After banks grant consumers loans, a blockchain-based KYC system is proposed in this study to collect limit, risk, and collateral information from them. The approach built upon Ethereum grants financial institutions the ability to read and write financial data on the blockchain network. This KYC method establishes a transparent, dynamic, and expeditious framework among financial institutions. In addition, solutions are discussed for the Sybil attack, one of the most severe problems in such networks.
Open Access
Boosting the Visibility of Services in Microservice Architecture
(Springer, 2023) TOKMAK, AHMET VEDAT; AKBULUT, AKHAN; Çatal, Çağatay
Monolithic software architectures are no longer sufficient for the highly complex software-intensive systems, which modern society depends on. Service Oriented Architecture (SOA) surpassed monolithic architecture due to its reusability, platform independency, ease of maintenance, and scalability. Recent SOA implementations made use of cloud-native architectural approaches such as microservice architecture, which has resulted in a new challenge: the discovery difficulties of services. One way to dynamically discover and route traffic to service instances is to use a service discovery tool to locate the Internet Protocol (IP) address and port number of a microservice. In the event that replicated microservice instances are found to provide the same function, it is crucial to select the right microservice that provides the best overall experience for the end-user. Parameters including success rate, efficiency, delay time, and response time play a vital role in establishing a microservice's Quality of Service (QoS). These assessments can be performed by means of a live health-check service, or, alternatively, by making a prediction of the current state of affairs with the application of machine learning-based approaches. In this research, we evaluate the performance of several classification algorithms for estimating the quality of microservices using the QWS dataset containing traffic data of 2505 microservices. Our research also analyzed the boosting algorithms, namely Gradient Boost, XGBoost, LightGBM, and CatBoost to improve the overall performance. We utilized parameter optimization techniques, namely Grid Search, Random Search, Bayes Search, Halvin Grid Search, and Halvin Random Search to fine-tune the hyperparameters of our classifier models. Experimental results demonstrated that the CatBoost algorithm achieved the highest level of accuracy (90.42%) in predicting microservice quality.
Open Access
Briot-Bouquet Differential Subordinations for Analytic Functions Involving the Struve Function
(MDPI, 2022) ÇETİNKAYA, ASENA; Cotirla, Luminita-Ioana
We define a new class of exponential starlike functions constructed by a linear operator involving normalized form of the generalized Struve function. Making use of a technique of differential subordination introduced by Miller and Mocanu, we investigate several new results related to the Briot-Bouquet differential subordinations for the linear operator involving the normalized form of the generalized Struve function. We also obtain univalent solutions to the Briot-Bouquet differential equations and observe that these solutions are the best dominant of the Briot-Bouquet differential subordinations for the exponential starlike function class. Moreover, we give an application of fractional integral operator for a complex-valued function associated with the generalized Struve function. The significance of this paper is due to the technique employed in proving the results and novelty of these results for the Struve functions. The approach used in this paper can lead to several new problems in geometric function theory associated with special functions.
Open Access
A Broadband, Polarization Insensitive, Wide Incidence-Angle-Slotted Ring/Lumped Resistor-Based Metamaterial Absorber for K-u-Band Applications
(Istanbul University - Cerrahpaşa, 2021) AKŞİMŞEK, HÜSEYİN SİNAN
A broadband-slotted ring/lumped resistor-based metamaterial absorber (MA) is presented in this study for K-u-band microwave applications. Numerical results of the MA indicate that it can achieve a broadband absorption ratio of more than 85% in the frequency range of 12.4-17.6 GHz and has active polarization insensitivity and wide incidence-angle response over the entire operation band between 12.4-17.6 GHz. The designed MA is ultrathin around lambda/14.7 in terms of wavelength at its lowest operation frequency, corresponding to 1.7 mm. The proposed unit-cell structure of the MA is novel, consisting of a slotted ring with eight symmetrically-located lumped resistors, FR-4 material, and a metallic ground, which is compatible with low-cost PCB fabrication; therefore, the MA is suitable for practical microwave applications in the K-u-band.
Open Access
Characterization of Site Amplification by a Parametric Study
(Taylor & Francis Inc., 2023) FERCAN, NAZİFE ÖZGE; Şafak, Erdal; Ansal, Atilla
The reliability of Vs30 and the performance of alternative time averaged shear wave velocities (Vsz) and shear wave travel times (Ttz) at various depths, z, were investigated for the estimation of site amplification and fundamental frequency (f0) characterization by considering the linear and nonlinear soil behavior. The study revealed that alternative parameters performed better than Vs30 and the best performing z parameters changed by switching from convex to concave theoretical profiles and by increasing ground motions. For a practical usage in site investigations, guidelines to estimate nonlinear soil amplification factor and fundamental frequency from the linear ones were presented.
Open Access
The City Experience with Location-Based Media: An Examination Through Cognitive Maps
(Konya Technical University, 2021) IAVARONE, AYŞENUR HİLAL; HASGÜL, ESİN; BAŞAR, EROL
Purpose The physical space has been an important value for supporting human experience. With the development of mobile devices and location-based media, these technologies have been increasingly present in our virtual spatial experience and the experience of physical city has been changed permanently. Accordingly, this paper aims to discuss the experience potential of urban space with location-based technologies. Design/Methodology/Approach The research structure of this study is based on the literature of location-based media and 'Space of flow' theory. Within the methodology, a workshop is conducted to review the cognitive mappings of the virtual city experience. The workshop is structured through two segments: Documenting the spatial experience revealed using location-based media made by cognitive mappings and testing participants' direct experiences within structured questionnaire-based interviews and finally, interpretating of the obtained data. Findings This paper provides an experiential examination of the relationship between the usage of the degree of location-based media and cognitive experience. Findings point out that experience may differ depending on the media interface used and it is controversial comparing with the physical space experience with its multiple relationships. Research Limitations/Implications The research subject had been exemplified with limited location-based media in a specific location. Originality/Value The proposed method of examining the degree of spatial experience by the location-based media linking with interviews determines the originality of the study. There are also limited studies on the topic of location-based media by focusing on the users' cognitive maps.
Open Access
Co-Chaperone Bag-1 Plays a Role in the Autophagy-Dependent Cell Survival Through Beclin 1 Interaction
(MDPI, 2021) Türk, Miray; Tatlı, Özge; Alkan, Hamza Furkan; KILBAŞ, PELİN ÖZFİLİZ; Alkurt, Gizem; Dinler Doğanay, Gizem
Expression levels of the major mammalian autophagy regulator Beclin 1 and its interaction with Bcl-2 regulate the switch between autophagic cell survival and apoptotic cell death pathways. However, some of the regulators and the precise mechanisms of these processes still remain elusive. Bag-1 (Bcl-2 associated athanogene-1), a member of BAG family proteins, is a multifunctional pro-survival molecule that possesses critical functions in vital cellular pathways. Herein, we report the role of Bag-1 on Bcl-2/Beclin 1 crosstalk through indirectly interacting with Beclin 1. Pull-down experiments suggested a molecular interaction between Bag-1 and Beclin 1 in breast cancer cell lines. On the other hand, in vitro binding assays showed that Bag-1/Beclin 1 interaction does not occur directly but occurs through a mediator molecule. Bag-1 interaction with p-Beclin 1 (T119), indicator of early autophagy, is increased during nutrient starvation suggesting involvement of Bag-1 in the autophagic regulation. Furthermore, CRISPR/Cas9-mediated Bag-1 knock-out in MCF-7 cells hampered cell survival and proliferation and resulted in decreased levels of total LC3 under starvation. Collectively, we suggest that Bag-1 modulates cell survival/death decision through maintaining macroautophagy as a component of Beclin 1-associated complexes.
Open Access
Coefficient Estimates for Bi-Univalent Functions in Connection with Symmetric Conjugate Points Related to Horadam Polynomial
(MDPI, 2020) Aydoğan, S. Melike; Karahüseyin, Zeliha
In the current study, we construct a new subclass of bi-univalent functions with respect to symmetric conjugate points in the open disc E, described by Horadam polynomials. For this subclass, initial Maclaurin coefficient bounds are acquired. The Fekete-Szego problem of this subclass is also acquired. Further, some special cases of our results are designated.
Open Access
Coefficient Inequalities for Certain Starlike and Convex Functions
(Hacettepe University, 2022) ÇETİNKAYA, ASENA; Kumar, Sushil
In this paper, we consider two Ma-Minda-type subclasses of starlike and convex functions associated with the normalized analytic function phi(Ne)(z) = 1 + z - z3/3 that maps an open unit disk onto the Nephroid shaped bounded domain in the right-half of the complex plane. We investigate convolution and quasi-Hadamard product properties for the functions belonging to such classes. In addition, we compute best possible estimates on third order Hermitian-To eplitz determinant and non-sharp estimates on certain third order Hankel determinants for the starlike functions associated with the interior region of Nephroid.