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Big Five Traits Predict Stress and Loneliness During the Covid-19 Pandemic: Evidence for the Role of Neuroticism
No full textThe rapid outbreak of the coronavirus disease (COVID-19) has affected citizens' daily lives in an unprecedented way. To curb the spread of the pandemic, governments have taken numerous measures such as social distancing and quarantine, which may be associated with psychological consequences, namely stress and loneliness globally. To understand differential associations of personality traits with psychological consequences of COVID-19, we utilize data from a sample of 99,217 individuals from 41 countries collected as part of the COVIDiSTRESS Global Survey. Data were analyzed using multigroup confirmatory factor analysis and multilevel regression models. Findings showed that while some of the associations were rather weak, Big Five personality traits were significantly associated with perceived stress and loneliness during the pandemic. Our study illustrates that neuroticism especially can be a vulnerability factor for stress and loneliness in times of crisis and can contribute to detection of at-risk individuals and optimization of psychological treatments during or after the COVID-19 pandemic. © 2022 Elsevier Lt
Stationary Characteristics for Renewal-Reward Process With Generalized Reflecting Barrier and Fuzzy Demands
No full textRenewal-reward processes with barriers are useful tools which are frequently applied in the fields of quantum physics as well as in some problems in various engineering areas. Especially, some problems in inventory theory can be modeled by means of renewal-reward processes with a generalized reflecting barrier. However, in inventory models, for instance, while predicting the distribution of the random variables such as demands or interarrival times, the entire distribution or some of its parameters can be fuzzy because of the vague information or some other subjective evaluations. Therefore, in this study, an inventory model is investigated by means of a renewal-reward process with a generalized reflecting barrier when the demands are fuzzy random variables. The aim of this study is to obtain exact expression and asymptotic expansions for the ?-cuts of ergodic distribution of the considered process which represents a fuzzy inventory model. Moreover, the asymptotic expansions for the ?-cuts of ergodic moments are derived. Particularly, a special case in which the demands have a Weibull distribution with a fuzzy parameter is studied in detail. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
Yeni Bir Türk Bitkisel Preparatın Huvec Üzerindeki Etkisinin İn Vitro Olarak Moleküler Düzeyde Araştırılması ve Fenolik Bileşen Analizi
No full textGiriş ve Amaç: Bitkisel ilaçlar geleneksel halk tıbbında uzun yıllardır kullanılmaktadır. Bu çalışmada, halk tıbbında anti-trombotik olarak kullanılan yeni bir Türk bitkisel preparatın (TBP) HUVEC üzerindeki etkilerinin in vitro hücre testleri ve proteomik analizlerle araştırılması ve fenolik bileşen analizinin yapılması amaçlanmıştır. Materyal ve Yöntem: Farklı bitkilerin kısımlarından (Türk yeşil çay yaprağı, tarçın kabuğu, nane, kekik, çörek otu gibi) elde edilen TBP etanolik ekstresi yarı yarıya seyreltilerek HUVEC’lere belirli sürelerde uygulanmıştır. Daha sonra hücrelerden protein izolasyonu yapılarak proteomik analizler gerçekleştirilmiştir. Kontrol ve uygulama gruplarının protein profilleri 2D-PAGE ile karşılaştırılmış, belirlenen protein kümelerindeki proteinler kütle spektrometresi ve biyoinformatik analizler ile tanımlanmıştır. MTT testi ile sitotoksisite değerlendirilmiş ve VEGF’yi hedef alan immünohistokimyasal boyama yapılmıştır. Ayrıca seçilmiş standartlar kullanılarak HPLC ile fenolik bileşen analizi yapılmıştır. Bulgular ve Sonuç: Proteomik analiz ile “calcium-independent phospholipase A2-gamma”, “SH2B adapter protein 1”, “mitochondrial uncoupling protein 2”, ve “hyaluronan and proteoglycan link protein 4” proteinleri tanımlanmıştır. Bu proteinler kontrol ve uygulama grupları arasında farklılık göstermektedir. Ayrıca immünohistokimyasal boyama sonuçlarına göre VEGF ifadesi de gruplar arasında farklılık göstermiştir. HPLC analizi, ekstrenin syringik asit, klorojenik asit gibi fenolik asitleri içerebileceğini göstermiştir ancak miktarları düşüktür.Tanımlanan proteinlerin hemostaz ve tromboz ile ilişkili olduğu bulunmuştur. Bu proteinlerin ifadesindeki değişimler, TBP’nin etki mekanizmasına katkı sağlıyor olabilir. VEGF’nin de benzer şekilde venöz tromboz ile etkileşimde olduğu bilinmektedir. Ekstre, fenolik bileşenler dışında başka maddeler de içerebilir ve etkisinde de büyük olasılıkla içerdiği tüm bileşenlerin sinerjistik etkileri rol oynamaktadır. Kapsamlı in vitro ve in vivo çalışmalar ile halk tıbbında kullanılan preparatın etkileri ve içeriği daha detaylı bir şekilde ortaya koyulabilecektir
The Impact of Natural Ventilation on Airborne Biocontaminants: a Study on Covid-19 Dispersion in an Open Office
No full textPurpose Biocontaminants represent higher risks to occupants' health in shared spaces. Natural ventilation is an effective strategy against indoor air biocontamination. However, the relationship between natural ventilation and indoor air contamination requires an in-depth investigation of the behavior of airborne infectious diseases, particularly concerning the contaminant's viral and aerodynamic characteristics. This research investigates the effectiveness of natural ventilation in preventing infection risks for coronavirus disease (COVID-19) through indoor air contamination of a free-running, naturally-ventilated room (where no space conditioning is used) that contains a person having COVID-19 through building-related parameters. Design/methodology/approach This research adopts a case study strategy involving a simulation-based approach. A simulation pipeline is implemented through a number of design scenarios for an open office. The simulation pipeline performs integrated contamination analysis, coupling a parametric 3D design environment, computational fluid dynamics (CFD) and energy simulations. The results of the implemented pipeline for COVID-19 are evaluated for building and environment-related parameters. Study metrics are identified as indoor air contamination levels, discharge period and the time of infection. Findings According to the simulation results, higher indoor air temperatures help to reduce the infection risk. Free-running spring and fall seasons can pose higher infection risk as compared to summer. Higher opening-to-wall ratios have higher potential to reduce infection risk. Adjacent window configuration has an advantage over opposite window configuration. As a design strategy, increasing opening-to-wall ratio has a higher impact on reducing the infection risk as compared to changing the opening configuration from opposite to adjacent. However, each building setup is a unique case that requires a systematic investigation to reliably understand the complex airflow and contaminant dispersion behavior. Metrics, strategies and actions to minimize indoor contamination risks should be addressed in future building standards. The simulation pipeline developed in this study has the potential to support decision-making during the adaptation of existing buildings to pandemic conditions and the design of new buildings. Originality/value The addressed need of investigation is especially crucial for the COVID-19 that is contagious and hazardous in shared indoors due to its aerodynamic behavior, faster transmission rates and high viral replicability. This research contributes to the current literature by presenting the simulation-based results for COVID-19 as investigated through building-related and environment-related parameters against contaminant concentration levels, the discharge period and the time of infection. Accordingly, this research presents results to provide a basis for a broader understanding of the correlation between the built environment and the aerodynamic behavior of COVID-19
3d Porous Pcl-Peg / Strontium, Magnesium and Boron Multi-Doped Hydroxyapatite Composite Scaffolds for Bone Tissue Engineering
No full textBioceramic/polymer composite systems have gained importance in treating hard tissue damages using bone tissue engineering (BTE). In this context, it was aimed to develop 3D porous composite PCL-PEG-PCL scaffolds containing different amounts of B, Sr and Mg multi-doped HA that can provide bone regeneration in the bone defect area and to investigate the effect of both the amount of inorganic phase and the porosity on the mechanical and the biological properties. B-Sr-Mg multi-doped HA and PCL-PEG-PCL copolymer were successfully synthesized. PCL-PEG-PCL composite scaffolds containing different amounts of hydroxyapatite (HA) (10% and 20 wt%) were produced with the desired porosity (50% and 60%) by compression-molding and particulate leaching method. The porosity of the scaffolds was determined between 47% and 59%. HA/PCL-PEG-PCL composite scaffolds were subjected to a 3-week degradation test and showed negligible (0.2-0.5%) degradation. The water uptake percentage of the composite scaffolds with 60% porosity was the highest among all groups. Presence of HA in the scaffolds improved the water adsorption and the mechanical properties. Compressive strength of the scaffolds was between 9.32 and 24.27 MPa and 20% 2Sr0.5BHA scaffolds were found to have the maximum compressive strength. Compressive strength of 50% porous samples was higher than that of 60% porous samples. In the relative cell viability (%) test, the highest viability was observed on the scaffolds with HA and 2Sr0.5BHA. The specific ALP activity level of the cells on the scaffolds containing 2Sr0.5BHA was significantly higher (2.6 times) than that of the control group. The amount of porosity did not make a significant difference in cellular response. It was concluded that PCL-PEG-PCL composite scaffolds with 2Sr0.5BHA have the potential to be used in BTE.This study has been financially supported by TUBITAK under the project number 217M264.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [217M264
Background of “Pinned” Images: Lifestyle Advertising in Social Media
No full textThe presence of a hidden enforcement is a matter in social media networks, whose contents are made attractive by rich images illustrating the rearrangement of the living spaces belonging to the followers of these networks. Every detail of private life including personal appearance, spaces where time is spent with friends, food is consumed, coffee is drunk, and houses are decorated, is presented through charming images. Inspired by these images, people have started to make their preferences regarding what mobile phone to use, what sports to practice, or what films to watch. The content of social media has begun to draw attention to “lifestyle advertising” and has provided a convenient ground for the advertising industry. Pinterest is a network where images reflecting modern people’s daily habits, including consumption, are pinned in order to serve as sources of inspiration. In this study, the perfect living spaces which have been fictionalised as models in the images shared on Pinterest will be investigated in terms of “lifestyle advertising” and in comparison to real life. © 2025 Elsevier B.V., All rights reserved
Understanding National Governments’ Desire To Regulate Crypto Currencies Through Pre-Westphalian Concepts of Sovereignty
No full textCrypto currencies, electronic currencies and block chain financial technologies (Fintech), have been debated issues whereby national governments are trying to put certain regulation upon them, especially citing security concerns. Crypto currencies can be used for money laundering, untraceable transactions of criminal and terrorist organizations and thus constitute genuine security risks. To many evangelists of these new technologies, governmental desires to impose regulations is viewed negatively. However, although usage of these technologies will likely continue to expand in the global economy, there is a desire to put them under regulation by most of the major nation states. It is necessary to understand the essence of currency as a tool of national sovereignty long before the age of the Westphalian concept of the modern state system. The desire to regulate Fintech derives from a concept of sovereign power that goes back to biblical times and far beyond the Westphalian notion of the sovereign and independent modern nation state. That notion of sovereignty rests on the power to mint money. Furthermore, the concept of such a sovereign power is observed in Ancient Rome, Medieval Europe as well as the early Islamic understanding of sovereign power. Thus it is essential to understand globally how the symbol of money has been a sovereignty symbol before starting any discussions on national or international levels of regulations
Investigation of the Transitions for Coplanar Waveguide To Terahertz Spoof Surface Plasmon Polariton Waveguides
No full textIn this article, we present the investigation and design of high-performance transitions from coplanar waveguide (CPW) to single-conductor, corrugated waveguides (WGs), namely, terahertz spoof surface plasmon polariton (SSPP) WGs. In contrast to the previous studies in the literature on CPW-to-SSPP WG transitions, we propose a novel methodology to examine the relationship between the guided wavenumber and momentum matching, which is based on analytical calculations, together with the effects of flaring grounds on transition performance. This novel methodology allows us to design a low-loss transition circuit (TC) for any given CPW and SSPP dimensions, which is demonstrated for the first time in the literature. We verify the proposed methodology by the design, fabrication, and measurement of several TCs. The measurement results show that the insertion losses of the proposed TCs can be as low as -1.2, -1, and -2.4 dB at 0.25, 0.275, and 0.3 THz, respectively, which brings a significant improvement of 0.6-2.3 dB in the 0.25-0.3 THz band, compared with the previously reported studies in the literature for the terahertz band.Scientific and Technological Research Council of Turkey (TUBITAK) [115E219]; Turkish Academy of Sciences Outstanding Young Scientist Award (TUBA GEBIP)This work was supported in part by The Scientific and Technological Research Council of Turkey (TUBITAK) under Grant 115E219 and in part by the Turkish Academy of Sciences Outstanding Young Scientist Award (TUBA GEBIP) 2015
Zamansal Çoklama Yöntemiyle Küçük Boyutlarda Cam Elyaf Polimer Katkili Mandrel Tabanli Fiber Optik Akustik Algilayicilarla Dizin Olusturulmasi
No full textFiber optic systems are well suited choice for underwater acoustic measurements with respect to conventional piezoelectric ceramic based systems. Main advantages of fiber optic systems are low cost, small size, light weight; high sensitivity and most importantly they are electromagnetic interference (EMI) free. Fiber optic interferometric acoustic systems have seen extensive development for military applications such as horbour protection sonars, towed array sonars, flank array sonars. and etc. Recently, due to the success in the military area, fiber optic interferometric acoustic sensors are also being used in commercial seabed sensing applications for oil/gas exploration and seismic research. There are many techniques for sensing acoustic pressure like FBG (Fiber Bragg Grating) based and mandrel based Mach-Zehnder interferometer systems. However, because of its high responsitivity, mandrel based Mach-Zehnder interferometer system has been preffered. In Mach-Zehnder interferometer system, laser light is split into the sensing and the reference arm. Some part of the laser light pass through fiber wounded around reference mandrel, remaining pass through fiber wounded acoustic pressure sensitive sensor arm. Pahse difference between two arms gives information about acoustic wave. In this thesis, A full-detailed design has been done considering sensor mandrel material type. Glass Fiber Reinforced Polymer (GFRP) has been chosen because of its strength, durability and sensitivity. To the best of our knowledge there is no detailed work based Glass Fiber Reinforced Polymer based fiber optic acoustic system. The results of these studies, which were carried out for the first time, are promising It is important to demodulate phase difference between reference and sensor arms. To decrease environmental effects and prevent phase fading, PGC (Phase Generated Carrier) method has been applied for the demodulation of the acoustic signal. As a result, we have demonstrated an high sensitive fiber optic underwater acoustic sensors. The pressure sensitivity of sensors are are around -150 dB re rad/µPa. System noise level is both analyzed and measured and it is better than 50 dB re µP a/√ Hz at low frequencies. Finally, main advantage of fiber optic systems is that it is easy to increase number of sensors. For this reason, considerable efforts has been put for the development of various techniques. Some of the most recent techniques are frequency division multiplexing (FDM), wavelength division multiplexing (WDM) and time division multiplexing (TDM). We demonstrate a time division multiplexed sensor array because of advantages on cost and small dimension.Akustik basınç algılama için konvansiyonel yöntemlerde piezo elektrik tabanlı seramikler kullanılmaktadır. Fakat, düşük bütçe, küçük ebat, yüksek hassasiyet ve en önemlisi elektromanyetik girişimlerden etkilenmemesi sebebiyle fiber optik sistemler, akustik ölçümlerde kullanılmaya başlanılmıştır. Fiber optik tabanlı akustik sistemler, liman gözetleme, askeri gemilerde çekili dizin sonarı ve yan dizin sonarı gibi pek çok alanda konvansiyonel sonar çözümlerine alternatif oluşturmaktadır. Askeri alanlardaki başarısının yanısıra fiber optik sistemler deniz altında petrol/gaz arama çalışmaları ve sismik araştırmalarda da kullanılmaktadır. Fiber tabanlı akustik algılama için dünyada FBG (Fiber Bragg Grating) teknolojisi ve mandrel tabanlı girişim (interforemetrik) sistemler üzerine çalışmalar yapılmaktadır. Yüksek hassasiyeti sebebiyle mandrel tabanlı Mach-Zehnder girişim sistemi bu tez kapsamında tercih edilmiştir. Bu yöndeki bir sistemde lazer ışığı fiber içerisinde iki kısma ayrılmaktadır. Lazer ışığının bir kısmı referans mandrele sarılı fibere giderken diğer kol ise üzerine gelen akustik basınca tepki veren sensör mandrel üzerine sarılı fibere gitmektedir. İki kol arasındaki faz farkı sensör mandrel üzerine gelen akustik dalga hakkında bilgi vermektedir. Tez kapsamında algılayıcı genel tasarımı yapılmış ve sensör kolu olarak kullanılan malzeme yapısı optimize edilmiştir. Farklı malzeme yapıları göz önünde bulundurularak sensör mandrel yapısı analiz edilmiştir. Akustik basınç algılama hassasiyeti ve dayanıklılık göz önünde bulundurularak cam elyaf katkılı polimer (GFRP) sensör mandrel malzemesi olarak tercih edilmiştir. Yapılan literatür araştırmaları sonucunda ulaşabildiğimiz bilgi dahilinde çam elyaf katkılı bir polimerle bu yönde bir çalışmaya rastlanılmamıştır. İlk defa detaylandırılan bu çalışmaların sonuçları umut vericidir. Bu yöndeki bir sistemde akustik bilginin çözümlenebilmesi için girişim düzeneğindeki sensör kolu ve referans kolu arasındaki faz farkı bilgisi elde edilmelidir. Akustik bilginin çözümlenmesinde çevresel etkilerden kaynaklı faz sönümlemesinin de önüne geçebilmek için faz kaynaklı taşıyıcı (PGC, Phase Generated Carrier) yöntemi tez kapsamında kullanılmıştır. Bu çalışmalar sonucunda yaklaşık -150 dB re rad/µP hassasiyete sahip fiber optik akustik algılayıcılar elde edilmiştir. Algılama için en önemli paremetre olan gürültü seviyesi için hem modelleme yapılmış hem de gerçek veriler toplanmıştır. Çalışmalar sonucunda sistem gürültü seviyesinin 50 dB re µP a/√ Hz altında olduğu görülmüştür. Son olarak bu yöndeki bir sistemin en önemli avantajı algılayıcıların aynı hat üzerinden kolayca çoklanabilmesidir. Bu kapsamda farklı alternatifler üzerine araştırmalar yapılmıştır. En önemli çoklama teknikleri Frekans Bölmeli Çoklama (FDM, Frequency Division Multiplexing), Dalgaboyu Bölmeli Çoklama (WDM, Wavelength Division Multiplexing) ve Zaman Bölmeli Çoklama (TMD, Time Division Multiplexing)'dır. Diğer çoklama yöntemlerine göre ebatların ve maliyetlerin düşmesi dolayısıyla TDM yöntemi tercih edilmiş bu yöntem üzerine çalışmalar yapılmıştır