Evaluation of solubility and viscosity of refrigerant/lubricant solutions

Convenient representations for the pressure, temperature, composition and viscosity of three refrigerant/lubricant mixtures are studied. Solubility results are obtained from different models for the activity of the mixtures and from application of thermodynamic perturbation theory.;Local composition models have the advantage that an approximate form for the temperature dependence of the activity is provided. This work provides an analysis of the applicability of local composition models based on Wilson\u27s treatment of the Flory-Huggins approximation for the lattice gas model in which site-site interactions are neglected. We have presented a modification of the Wilson\u27s approach in which site-site interactions in the lattice gas model are retained. We compare the accuracy of these local composition models with the simple Margules equation. The utility of the local composition approach is dependent upon the correctness of the assumed temperature dependence. The constants contained in these expressions can not be applied for prediction of the thermodynamic properties for which no experimental data is available. In contrast, group contribution methods are phrased in terms of parameters which are transferrable to other mixtures for which no thermodynamic property information exists. Here we consider the UNIFAC and evaluate the interaction parameters for R12/hydrocarbon and R22/hydrocarbon binary groups .;Thermodynamic perturbation theory predicts pressure as a function of temperature and composition without requiring the calculation of the activity coefficients.;Well established methods given in the literature are used for the prediction of mixture viscosities and results are compared with the experimental data provided by the Refrigeration Laboratory at Iowa State University

Nilotinib significantly induces apoptosis in imatinib resistant K562 cells with wild-type BCR-ABL, as effectively as in parental sensitive counterparts

Chronic myeloid leukemia (CML) is a hematological malignancy characterized by high levels of immature white blood cells. CML is caused by the translocation between chromosomes 9 and 22 (which results in the formation of the Philadelphia chromosome) creating BCR-ABL fusion protein. Imatinib and nilotinib are chemotherapeutic drugs which specifically bind to the BCR-ABL and inhibit cancer cells. Nilotinib is more effective in this respect than imatinib. We have shown that nilotinib induces apoptosis in imatinib-resistant K562 CML cells which have the wild-type BCR-ABL fusion gene almost to the same extent as it does in the parental sensitive cells by the increase in caspase-3 enzyme activity and the decrease in mitochondrial membrane potential. This effect of nilotinib, even in low concentrations, may indicate the efficacy of the usage of nilotinib in imatinib-resistant CML with less risk of undesired cytotoxic effects in the remaining cells of the body. © 2010 W. S. Maney & Son Ltd

Apoptotic effects of resveratrol, a grape polyphenol, on imatinib-sensitive and resistant K562 chronic myeloid leukemia cells

To examine the antiproliferative and apoptotic effects of resveratrol on imatinib-sensitive and imatinib-resistant K562 chronic myeloid leukemia cells. Antiproliferative effects of resveratrol were determined by the 3-Bis[2-methoxy-4-nitro-5-sulphophenyl]-2H-tetrazolium-5-carboxanilide inner salt (XTT) cell proliferation assay. Apoptotic effects of resveratrol on sensitive K562 and resistant K562/IMA-3 cells were determined through changes in caspase-3 activity, loss of mitochondrial membrane potential (MMP), and apoptosis by annexin V-(FITC). The concentrations of resveratrol that inhibited cell growth by 50% (IC(50)) were calculated as 85 and 122 μM for K562 and K562/IMA-3 cells, respectively. There were 1.91-, 7.42- and 14.73-fold increases in loss of MMP in K562 cells treated with 10, 50, and 100 μM resveratrol, respectively. The same concentrations of resveratrol resulted in 2.21-, 3.30- and 7.65-fold increases in loss of MMP in K562/IMA-3 cells. Caspase-3 activity increased 1.04-, 2.77- and 4.8-fold in K562 and 1.02-, 1.41- and 3.46-fold in K562/IMA-3 cells in response to the same concentrations of resveratrol, respectively. Apoptosis was induced in 58.7%- and 43.3% of K562 and K562/IMA-3 cells, respectively, in response to 100 μM resveratrol. Taken together these results may suggest potential use of resveratrol in CML, as well as in patients with primary and/or acquired resistance to imatinib

Management of patients with connective tissue disease-associated interstitial lung diseases during the COVID-19 pandemic

The novel coronavirus disease (COVID-19) is similar to connective tissue disease-associated interstitial lung diseases (CTD-ILD) in many aspects. However, patients with CTD-ILD have required particular attention during the pandemic since they are at high risk due to -immunosuppressive treatments. Thus, prompt decisions for diagnosis and treatment initiation have become more important than earlier for these patients during the pandemic. Radiological perspectives have become inevitable for the differential diagnosis of this group -during the pandemic, particularly to obtain rapid and accurate results that allow the physicians to start treatment immediately. However, in addition to radiological images, a definitive diagnosis also requires access to extensive information regarding patient history, including characteristics of comorbidities, and clinical and serological findings. Consequently, the differential diagnosis of COVID-19 and CTD-ILD can yield accurate treatment regimens that differ greatly between the 2 diseases, and also prevent the spread of the outbreak with COVID-19 patients treated under isolation

Multidrug resistance mediated by MRP1 gene overexpression in breast cancer patients

Multidrug resistance (MDR) is a serious handicap towards the effective treatment of breast cancer patients. One of the most prevalent MDR mechanisms is through the overexpression of genes coding the proteins called Multidrug Resistance-associated Proteins (MRPs). The aim of this study was to investigate the expression of MRP1 in tumor tissues from breast cancer patients. In this study, a semi-quantitative RT-PCR approach was utilized. Our results suggest that MRP1 overexpression can mediate MDR in patients. Pre-evaluation of the level of such MDR mediators before chemotherapy can increase the efficacy of the treatment

Determination and implementation of appropriate methods for the risk assessment of less repetitive tasks in a company

Ergonomi konusundaki en önemli çalışma alanlarından birini kas iskelet sistemi rahatsızlıkları (KİSR) oluşturmaktadır. Ancak bir çalışanın günlük işinde az yer tutan işlerde KİSR risklerinin değerlendirilmesi, analizlerin uzun ve detaylı çalışma gerektirmesinden dolayı genellikle görmezden gelinmekte veya ertelenmektedir. Bu çalışmada az tekrarlı işlerde ergonomik risklerin değerlendirilmesi için bir kontrol listesi hazırlanması amaçlanmıştır. Bu liste ile riskler pratik ve hızlı bir şekilde değerlendirilerek önlemler için öncelikleri belirlenebilecektir. Çalışmada, bir otomotiv işletmesinde çalışanın günlük çalışmasının %25’inden az zaman alan işlemler dikkate alınmıştır. Bu işlemlerin gerektirdiği hareket türleri; yük elleçleme, kuvvet uygulama ve itme-çekme olmak üzere üç grup altında toplanmıştır. Her hareket türü için, literatürdeki EAWS, AWS-Light, NIOSH, EN1005-2, ISO11228-1 ve OCRA yöntemlerinde belirtilen limit değerler kullanılarak bir kontrol listesi oluşturulmuştur. Örnek olarak analiz edilen iki farklı işlemde, önerilen kontrol listesi ile detaylı analizler aynı sonucu vermiştir. Böylece özellikle az tekrarlı işlerin en az 5 işgünü sürecek detaylı analizler yerine, önerilen kontrol listesi ile yarım saat içerisinde değerlendirilmesi sağlanmıştır.Musculoskeletal disorders (MSD) are one of the most important areas of study on ergonomics. However, assessing the MSD risks in operations that take less time in an employee’s daily work is neglected or delayed because the analysis requires long and detailed study. In this study, it was aimed to prepare a checklist for evaluating ergonomic risks in less repetitive tasks. With this list, risks can be assessed and prioritized in a practical and rapid manner. In the study, operations which take less time than 25% of the daily work of an employee in an automotive company were taken into account. The types of movements that these operations require are divided in three groups; load handling, force application and push-pull. For each type of movement, the current standards in the literature were reviewed to define the limits that may pose a risk for the musculoskeletal system. In the two different processes that were analyzed as examples, the proposed checklist and the detailed analyzes gave the same result. Thus, rather than the detailed analyzes that will last at least 5 working days, especially for the less repetitive tasks, the recommended checklist provides results within half an hour.Publisher's Versio

A High Throughput Lab-On-A-Chip System for Label Free Quantification of Breast Cancer Cells under Continuous Flow

This paper presents an LOC system combining microfluidic DEP channel with a CMOS image sensor for label and lens free detection and real-time counting of MCF-7 cells under continuous flow. Trapped and then released MCF-7 cells are accurately detected and counted under flow with a CMOS image sensor integrated underneath the DEP channel, for the first time in the literature. CMOS image sensor can capture 391 frames per second (fps) that allows detection of the released cells flowing through the channel with a flow rate up to 130 mu l/min (0.468 m/s). Therefore, the proposed system is able to detect the cells under high flow where conventional techniques for cell quantification such as fluorescent tagging become unusable. Detected cells are automatically counted with a computer program and the counting accuracy of the whole system is 95%. (C) 2016 The Authors. Published by Elsevier Ltd

A microfluidic device enabling drug resistance analysis of leukemia cells via coupled dielectrophoretic detection and impedimetric counting

© 2021, The Author(s).We report the development of a lab-on-a-chip system, that facilitates coupled dielectrophoretic detection (DEP-D) and impedimetric counting (IM-C), for investigating drug resistance in K562 and CCRF-CEM leukemia cells without (immuno) labeling. Two IM-C units were placed upstream and downstream of the DEP-D unit for enumeration, respectively, before and after the cells were treated in DEP-D unit, where the difference in cell count gave the total number of trapped cells based on their DEP characteristics. Conductivity of the running buffer was matched the conductivity of cytoplasm of wild type K562 and CCRF-CEM cells. Results showed that DEP responses of drug resistant and wild type K562 cells were statistically discriminative (at p = 0.05 level) at 200 mS/m buffer conductivity and at 8.6 MHz working frequency of DEP-D unit. For CCRF-CEM cells, conductivity and frequency values were 160 mS/m and 6.2 MHz, respectively. Our approach enabled discrimination of resistant cells in a group by setting up a threshold provided by the conductivity of running buffer. Subsequent selection of drug resistant cells can be applied to investigate variations in gene expressions and occurrence of mutations related to drug resistance

Kanser ve çoklu ilaç dirençliliği tespiti için mems tabanlı dielektroforetik hücre ayrıştırma sistemi geliştirilmesi

TÜBİTAK EEEAG01.06.2015Kanser tüm dünyada en önemli ikinci ölüm sebebi olup, her yıl 8.2 milyon insan kanser nedeniyle hayatını kaybetmektedir. Kanser tedavisinde başarının en önemli etkenlerinden biri erken teşhistir. Metastaz ve çoklu ilaç dirençliliği (ÇİD) ise ölüm oranının artmasına neden olan en önemli iki sebeptir. Bu nedenle metastaz ve ÇİD gelişiminin tedavi öncesi ve süresince takip edilmesi, uygun tedavi yönteminin seçilebilmesi açısından oldukça önemlidir. Ancak, klinikte metastaz ve ÇİD gelişiminin tespitine yönelik yaygın olarak kullanılabilen bir yöntem bulunmamaktadır. Önerilen projenin temel amacı şüphelenilen dokuda kanser hücrelerinin varlığını tespit eden ve bu kanser hücrelerinin çoklu ilaç direnci (ÇİD) mekanizması geliştirip geliştirmediğinin kontrolünü sağlayan, dielektroforez (DEF) tabanlı bir hücre ayrıştırma sistemi geliştirilmesidir. Bu iki aşamalı DEF sisteminin, ilk aşamada kanser ve normal doku hücrelerini boyut farklılıklarına göre, ikinci aşamada ise ÇİD geliştirmiş kanser hücrelerini diğer kanser hücrelerinden dielektrik özelliklerindeki farklılığa göre ayırması beklenmektedir. Proje süresince, simülasyon ve test sonuçlarına bağlı olarak her iki DEF alanı için 3 farklı nesil DEF çipi geliştirilmiştir. Projenin son aşamasında, son tasarımlar birleştirilerek iki aşamalı bir DEF çipi tasarımı yapılmış ve MEMS üretimleri gerçekleştirilmiş. Tasarımların testleri hassas ve dirençli MCF-7 meme kanseri ve K562 lösemi hücreleri ile gerçekleştirilmiştir. Kan hücrelerini K562 kanser hücrelerinden ayrıştırması planlanan birinci aşama DEF çipinin 1000 kat seyreltilmiş kırmızı kan hücresi (5x106 kan hücresi/ml) içinde 1x106 hücre/ml kanser hücresini ayrıştırabildiği gözlenmiştir. İkinci aşama DEF çipi ise 100 hassas kanser hücresi içinden 1 dirençli kanser hücresini ayrıştırabilecek hassasiyettedir. Proje kapsamında kullanılan hücrelerin hassas bir şekilde dielektrik karakterizasyonlarını yapabilecek özgün bir elektrorotasyon (ER) çipi geliştirilmiş ve farklı ilaç dirençlilik seviyesine sahip MCF-7 meme kanseri ve K562 lösemi hücrelerinin dielektrik özellikleri belirlenmiştir. Sonuç olarak, DEF yönteminin herhangi bir biyolojik işaretlemeye gerek duyulmaksızın hassas ve hızlı bir şekilde kanser ve kanserde ÇİD gelişimini tespit edebilecek bir platform olabileceği gösterilmiştir. Proje süresince elde edilen veriler, kanserde metastaz ve ÇİD gelişiminin erken tespitini sağlayabilecek MEMS-tabanlı bir çip-üstü-laboratuvar sisteminin geliştirilmesi için temel oluşturacak niteliktedir.Cancer has the 2nd rank in the mortality all over the world. 8.2 million people die due to cancer every year. Early diagnosis is one of the most crucial parameter in the cancer therapy. Metastasis and multidrug resistance (MDR) are the two reasons, causing to increase of death rate in cancer. Therefore, the observation of the metastasis and the development of MDR in cancer patient is crucial to determine the accurate therapy. However, there are not any method to detect metastasis and MDR in the clinic. The main objective of the proposed project is to develop a dielectrophoresis (DEP) based cell separation system (i) to detect cancer cells obtained from the suspected tissue, and also (ii) to separate the MDR cancer cells from non-resistant ones. The proposed two- stage DEP system is supposed to separate cancer cells from normal tissue cells due to their size differences at the first stage, and separate MDR cells from non-resistant ones due to differences in their dielectric properties at the second stage. Three generations were developed for both DEP stages based on the simulations and test results. At the last stage of the project, last generations were merged and two-stage DEP device was designed and fabricated. MDR and sensitive K562 and MCF7 cell lines were utilized in the tests of integrated DEP devices. At the first stage, K562 cancer cells (1x106cells/ml) were separated from blood cells (5x106cells/ml). The second DEP stage has the selectivity to detect one MDR cancer cell inside 100 sensitive ones. During the project, an electrorotation (ER) device was developed to characterize the cells dielectrically. The dielectric properties of MCF7 and K562 cells, having different drug resistance levels, were determined by utilizing ER devices. In conclusion, results prove that DEP can provide an efficient and rapid platform for the detection of cancer and MDR in cancer, in a label-free manner. These results form a basis for the development of a MEMS based lab-on-a-chip system to provide early diagnosis of metastasis and MDR in cancer