31 research outputs found

    Temporal segregation of biosynthetic processes is responsible for metabolic oscillations during the budding yeast cell cycle

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    Many cell biological and biochemical mechanisms controlling the fundamental process of eukaryotic cell division have been identified; however, the temporal dynamics of biosynthetic processes during the cell division cycle are still elusive. Here, we show that key biosynthetic processes are temporally segregated along the cell cycle. Using budding yeast as a model and single-cell methods to dynamically measure metabolic activity, we observe two peaks in protein synthesis, in the G1 and S/G2/M phase, whereas lipid and polysaccharide synthesis peaks only once, during the S/G2/M phase. Integrating the inferred biosynthetic rates into a thermodynamic-stoichiometric metabolic model, we find that this temporal segregation in biosynthetic processes causes flux changes in primary metabolism, with an acceleration of glucose-uptake flux in G1 and phase-shifted oscillations of oxygen and carbon dioxide exchanges. Through experimental validation of the model predictions, we demonstrate that primary metabolism oscillates with cell-cycle periodicity to satisfy the changing demands of biosynthetic processes exhibiting unexpected dynamics during the cell cycle.</p

    The Effect of COVID-19 Pandemic on the Hip Fractures in Advanced Age

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    Objective: Hip fractures due to domestic low-energy traumas are common problems that can cause significant morbidity and mortality in the elderly population. Since the Covid-19 outbreak, although the lock-down of older people could decrease contagion,the incidence of domestic traumas did not decrease, and led to development of various comorbidities. In this study, we aimed to compare the epidemiology of hip fractures in 6 months of the pandemic in 2020, with the equivalent 6-month period in the previous year to determine the relationship between lock-down and hip fractures due to domestic falls. Method: In this retrospective study, patients over 65 years old who were hospitalized due to hip fractures between May 1st, 2020 - November 30th, 2020 were compared with the similar cohort hospitalized between May 1st, 2019 - November 30th, 2019. The patients were compared in terms of demographic characteristics, American Society of Anesthesiologists (ASA) scores, type of anesthesia, time until surgery, comorbidities, surgical treatment modality, need for postoperative primary care unit, postoperative complications, and mortality. Results: Overall, 210 patients were included in our study. There was no significant difference between the groups regarding demographic characteristics and ASA scores. In the 2020 group, there were eight patients (8.6%) who were Covid-19 PCR- positive. There was no death proven by PCR that was related to COVID-19 disease. Time to surgery, fracture type, anesthesia type did not differ between the two groups. The need for a postoperative primary care unit was higher in the 2020 group. Ninety-day mortality rates were not significantly different between the two groups. Conclusions: In conclusion, despite higher mortality rates described in the literature, there was no Covid -19 associated mortality in our study. Hip fractures in the elderly did not alter with social mobilization; hence they usually occur due to domestic low- energy traumas. Reporting of the information in this patient group by all centers will provide important data in the management of hip fractures in this special process

    Development of a novel non-invasive biomarker panel for hepatic fibrosis in MASLD

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    Accurate non-invasive biomarkers to diagnose metabolic dysfunction-associated steatotic liver disease (MASLD)-related fibrosis are urgently needed. This study applies a translational approach to develop a blood-based biomarker panel for fibrosis detection in MASLD. A molecular gene expression signature identified from a diet-induced MASLD mouse model (LDLr−/−.Leiden) is translated into human blood-based biomarkers based on liver biopsy transcriptomic profiles and protein levels in MASLD patient serum samples. The resulting biomarker panel consists of IGFBP7, SSc5D and Sema4D. LightGBM modeling using this panel demonstrates high accuracy in predicting MASLD fibrosis stage (F0/F1: AUC = 0.82; F2: AUC = 0.89; F3/F4: AUC = 0.87), which is replicated in an independent validation cohort. The overall accuracy of the model outperforms predictions by the existing markers Fib-4, APRI and FibroScan. In conclusion, here we show a disease mechanism-related blood-based biomarker panel with three biomarkers which is able to identify MASLD patients with mild or advanced hepatic fibrosis with high accuracy.</p

    Development of a novel non-invasive biomarker panel for hepatic fibrosis in MASLD

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    Accurate non-invasive biomarkers to diagnose metabolic dysfunction-associated steatotic liver disease (MASLD)-related fibrosis are urgently needed. This study applies a translational approach to develop a blood-based biomarker panel for fibrosis detection in MASLD. A molecular gene expression signature identified from a diet-induced MASLD mouse model (LDLr−/−.Leiden) is translated into human blood-based biomarkers based on liver biopsy transcriptomic profiles and protein levels in MASLD patient serum samples. The resulting biomarker panel consists of IGFBP7, SSc5D and Sema4D. LightGBM modeling using this panel demonstrates high accuracy in predicting MASLD fibrosis stage (F0/F1: AUC = 0.82; F2: AUC = 0.89; F3/F4: AUC = 0.87), which is replicated in an independent validation cohort. The overall accuracy of the model outperforms predictions by the existing markers Fib-4, APRI and FibroScan. In conclusion, here we show a disease mechanism-related blood-based biomarker panel with three biomarkers which is able to identify MASLD patients with mild or advanced hepatic fibrosis with high accuracy.</p

    Biyodizel ve Karışımlarının Kullanıldığı bir Dizel Motorda Performans ve Emisyon Analizi

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    Bu çalışmada, atık palmiye yağı kökenli biyodizel ve petrol kökenli dizel yakıtı (PKDY) ile karışımlarının, bir dizel motordaki performans ve emisyon karakteristikleri üç boyutlu haritalar üzerinden analiz edilmiştir. Biyodizel ve karışımlarının performans ve emisyon karakterlerini belirlemek amacıyla, motor tam yük ve değişik devir testlerine tabi tutulmuştur. Analiz sonucunda, karışımdaki biyodizel oranı arttıkça PKDY'a göre özgül yakıt tüketiminde artış olduğu, motorun döndürme momentinde ise azalma meydana geldiği tespit edilmiştir. Emisyon analizi sonucunda ise, karışımdaki biyodizel oranı ile ilişkili olarak PKDY'a kıyasla yanmamış hidrokarbon (HC), karbon monoksit (CO) ve duman koyuluğu emisyonlarında iyileşmeler olduğu, bununla birlikte karbon dioksit (CO2) ve azot oksit (NOx) emisyonlarının motor devrine göre kararlı bir yapı sergilemediği belirlenmiştir

    Analysis of Performance and Emmissions in a Diesel Engine Fueled with Biodiesel and Blends

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    In this study, the performance and emission characteristics of biodiesel based waste palm oil and its blends with petroleum based diesel fuel (PBDF) was analyzed by means of three dimensional maps. In order to determine the engine performance and exhaust emission characteristics, the engine was exposed with full load and varied speed tests. In the result of analyze, it was seen that the brake specific fuel consumptions increased with the increase of biodiesel percentage in the fuel blend, but brake torque decreased depending upon biodiesel percentage in the fuel. In the result of emission analyze, it has determined that biodiesel and its blends has provided significant improvements in HC, CO and smoke opacity emissions. However, the stable behaviors in NOx and CO2 emissions of biodiesel and its blends did not seen in terms of the engine speed

    Propolis and the immune system

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    The use of propolis for medicinal purposes goes back to ancient times. The immunomodulatory action of propolis has been mainly attributed to its phenolic constituents, especially caffeic acid phenethyl ester (CAPE), which originated from the temperate zone propolis and artepillin C from Brazilian green propolis. Studies showed that propolis and its constituents had an immunomodulatory effect on both innate and adaptive immunity. Moreover, due to antimicrobial, antioxidant, antiinflammatory, and immunomodulatory properties, propolis-containing products have been used to prevent and treat various disorders, including asthma, upper respiratory tract diseases, gastrointestinal disorders, allergies, and dermatological problems. Although propolis and its constituents have an immunomodulatory effect, their mechanism of action is not entirely understood. The findings indicated that propolis and CAPE inhibited nitric oxide production in macrophages and modulated innate immunity by downmodulating the proinflammatory activity of monocytes. The effect of propolis on adaptive immunity can be both immunosuppressive and immunostimulant activity associated with the concentration of propolis. © 2022 Elsevier Inc. All rights reserved

    BİODİZELİN OKSİTLENME KARARLILIĞI ÜZERİNE DENEYSEL BİR ARAŞTIRMA

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    Biodizel, dizel motorları için hayvansal ve bitkisel yağlar gibi yenilenebilir kaynaklardan üretilen alternatif bir dizel yakıtıdır. Bitkisel ve hayvani yağlar, alkil mono esteri üretmek için bir alkol ile reaksiyona sokulur ve elde edilen ester, motor üzerinde hemen hemen hiç değişiklik yapılmadan kullanılabilir. Biodizel, yüksek oranlı doymamış yağlardan üretildiğinde, dizel yakıtından çok daha hızlı bir şekilde oksitlenir. Bu çalışmada, biodizelin hızlandırılmış oksitlenme test sonuçları sunulmuştur. Bu testler, zamanın, oksijen akış oranının, sıcaklığın, metallerin ve farklı biodizel hammaddelerinin, oksitlenme üzerine etkisini göstermektedir. Ayrıca üretilen biodizeller, motorinle karışım oluşturularak ve antioksidanlar ilave edilerek de incelenmiştir. Deneysel çalışmaların sonucu, normal dizel motor sıcaklıklarında antioksidan içermeyen biodizelin çok daha çabuk bir şekilde oksitlendiğini göstermektedir. Bu oksitlenme işleminde, peroksit, asit ve viskozite değerlerinde artış gözlemlenmiştir. Peroksit yaklaşık 350 meq O2/kg değerine ulaştıktan sonra sabit kalmakta, asit ve viskozite değeri ise periyodik olarak artmaktadır

    AN EXPERIMENTAL INVESTIGATION ON OXIDATIVE STABILITY OF BIODIESEL

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    Biodiesel is an alternative fuel for diesel engines that can be produced from renewable feed stocks such as vegetable oil and animal fats. These feed stocks are reacted with an alcohol to produce alkyl monoesters. The obtained ester can be used in conventional diesel engines with little or no modification. Biodiesel, especially if produced from highly unsaturated oils, oxidizes more rapidly than diesel fuel. This paper reports the results of accelerated oxidation tests on biodiesel. These tests show the impact of time, oxygen flow rate, temperature, metals, and feedstock type on the rate of oxidation. Blending with diesel fuel and the addition of antioxidants are also explored. The data indicate that without antioxidants, biodiesel will oxidize very quickly at temperatures typical of diesel engines. This oxidation results in increases in peroxide value, acid value, and viscosity. While the peroxide value generally reaches a plateau of about 350 meq O2/kg, the acid value and viscosity increase monotonically as oxidation proceeds
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