Enhancement of Heat Transfer Performance of a Heat Pipe by Using Calcium Magnesium Carbonate-Ethylene Glycol/Water Nanofluid with Sodium Dodecylbenzene Sulfonate

In this paper, the effect of using CaMg(CO3)2/Ethylene Glycol-water (50:50%) as a working fluid on the thermal performance of thermosyphon heat pipe was experimentally studied. Nanofluid was prepared by two-step method using 2% concentration of CaMg(CO3)2 nanoparticle and 0.05% surfactant (Sodium dodecylbenzene sulfonate). For the experimental set-up, a straight copper pipe of one-meter length was used. The inner diameter of the pipe is 13 mm, and the outer diameter is 15 mm. Experiments were conducted at three different cooling water mass flow rates (5, 7.5, and 10 g/s) and different heating powers (200, 300, 400 W) to test heat pipe performance. It was observed that the CaMg(CO3)2 nanofluid reduced the average wall temperature of the heat pipe according to the base fluid. Furthermore, the efficiency and thermal resistance of the heat pipe were investigated separately for EG/water and CaMg(CO3)2 nanofluid. The maximum heat transfer enhancement was obtained as 9.55% under 400 W heating power and 10 g/s cooling water mass flow rate conditions and the maximum improvement in thermal resistance was observed as 21% at 200 W and 10 g/s cooling mass flow rate. Viscosity and specific heat of base fluid and CaMg(CO3)2 nanofluid were also determined and compared to each other

Comparison of two pandemics: H1N1 and SARS-CoV-2

OBJECTIVE: We aimed to compare the clinical, epidemiological, and prognostic features of the H1N1 pandemic in 2009 and the severe acute respiratory syndrome coronavirus 2 pandemic in 2020. METHODS: This retrospective study involved subjects from seven centers that were admitted and found to be positive for H1N1 or COVID-19 real-time polymerase chain reaction test. RESULTS: A total of 143 patients with H1N1 and 309 patients with COVID-19 were involved in the study. H1N1 patients were younger than COVID-19 ones. While 58.7% of H1N1 patients were female, 57.9% of COVID-19 patients were male. Complaints of fever, cough, sputum, sore throat, myalgia, weakness, headache, and shortness of breath in H1N1 patients were statistically higher than in COVID-19 ones. The duration of symptoms until H1N1 patients were admitted to the hospital was shorter than that for COVID-19 patients. Leukopenia was more common in COVID-19 patients. C-reactive protein levels were higher in COVID-19 patients, while lactate dehydrogenase levels were higher in H1N1 ones. The mortality rate was also higher in H1N1 cases. CONCLUSIONS: The severe acute respiratory syndrome coronavirus 2 pandemic is a major public health problem that continues to affect the world with its high rate of contagion. In addition, no vaccines or a specific drug for the benefit of millions of people have been found yet. The H1N1 pandemic is an epidemic that affected the whole world about ten years ago and was prevented by the development of vaccines at a short period. Experience in the H1N1 pandemic may be the guide to prevent the COVID-19 pandemic from a worse end

Simple synthesis and sensing applications of a new and low cost fluorescent chemosensor for selective recognition and facile removal of Hg2+

WOS:000646669900007We thank the Research Foundation of KMU University for financial support of this work.A novel 5-(2-Benzothiazolyl)-2-hydroxybenzaldehyde (ALD) based probe NETBZ has been fabricated as a fluorogenic probe for sensitive detection of Hg2+ ions in CH3CN:HEPES (70/30, v/v, pH: 7.0) media. The probe NETBZ exhibited turn-off behavior from blue to colorless under UV light, in the presence of Hg2+ with limit of detection (LOD) (3σ/K) of 14.3 nM. In the presence of various cations (Mn2+, Cr3+, Ba2+, K+, Cu2+, Cd2+, Co2+, Ca2+, Zn2+, Mg2+, Ni2+, Fe2+, Sr2+, Pb2+, Fe3+ and Al3+), no significant changes were observed in its spectral patterns. The mechanism of the NETBZ-Hg2+ system could be thanks to chelation-enhanced fluorescence quenching (CHEQ), which was further confirmed by DFT computation, Job's method, and also 1H-NMR titration. The binding constant of probe NETBZ with Hg2+ from the Benesi-Hildebrand equation was found as 3.67 × 1015 M−3. Furthermore, new fluorescence strips based on TLC plate application for NETBZ and NETBZ-Hg2+ system was fabricated.We thank the Research Foundation of KMU University for financial support of this work

A?ırlıkça büyüme e?rilerinin oluşturulmasında nonparametrik kantil regresyon ve en küçük medyan kareler regresyonunun kullanımı

Objective: This study aimed to investigate the use of the Least Median Squares (LMS) regression and nonparametric quantile regression model comparatively to describe children?s weight growth. Material and Methods: Two different models were used to obtain the percentile curves to identify the weight growth in girls. The first model was obtained by LMS regression, which is a member of the family of nonlinear parametric quantile regression. In addition, in this model percentile curves used to define growth were generated using the Box-Cox transformation and the cubic spline. The second model was obtained by nonparametric quantile regression that did not require the assumption of a normal distribution for construction of percentile curves. This method is a flexible approach, as well as being computationally simple. The weight values obtained from 1771 healthy girls aged between 6 and 14 years were used in both methods. The data were collected from the cross-sectional study conducted in schools in Düzce city. Results: The distributions of weight measurements according to ages revealed that there were deviations from normality at some ages, there were deviated values in the tail regions of the distribution, and the variances changed according to ages. Using both methods, growth curves were constructed separately for each age group. Predicted values of the LMS and the non-parametric quantile regression models were similar for each age. In addition, the error sum of squares derived from non-parametric quantile regression was lower than that derived from LMS regression for each percentile curve. Moreover, the estimations obtained from both methods were highly correlated with the estimation values of the province İstanbul, which was considered the reference. Conclusion: When the assumptions about the distribution and variances of the data are violated and these assumptions cannot be achieved with the transformation, nonparametric quantile regression method gives more reliable results for the creation of percentile curves. © 2013 by Türkiye Klinikleri

Fabrication and sensing properties of phenolphthalein based colorimetric and turn–on fluorogenic probe for CO32− detection and its living–cell imaging application

WOS:000656959000066PubMed ID: 33676708Herein, an easy assembled colorimetric and ''turn–on'' fluorescent sensor (probe P4SC) based on phenolphthalein was developed for carbonate ion (CO32−) sensing in a mixture of EtOH/H2O (v/v, 80/20, pH = 7, Britton–Robinson buffer) media. The probe P4SC demonstrated high sensitive and selective monitoring toward CO32− over other competitive anions. Interaction of CO32− with the probe P4SC resulted in a significant increment in emission intensity at λem = 498 nm (λex = 384 nm) due to the strategy of blocking the photo induced electron transfer (PET) mechanism. 1H NMR titration and Job's methods, as well as the theoretical study were carried out to support the probable stoichiometry of the reaction (1:2) between P4SC and CO32−. The binding constant of the probe P4SC with CO32− was calculated as 2.56 × 1010 M−2. The probe P4SC providing rapid response time (~0.5 min) with a satisfactorily low detection limit (14.7 nM) may be useful as a valuable realistic sensor. The imaging studies on the liver cancer cells (HepG2) shows the great potential of the probe P4SC for the sensation of intracellular CO32− anions. Furthermore, the satisfactory recovery and RSD values obtained for water application confirming that the probe P4SC could be applied to sensing of CO32− ion.This work was supported by the Karamanoglu Mehmetbey University with the financial support to use Gaussian-09 and GaussView-5.0.8 software packages (BAP-Grant Numbers: 15-YL-17, 14-YL-20 and 05-M-20)

Design of multiple-target chemoprobe: “naked-eye” colorimetric recognition of Fe3+ and off–on fluorogenic detection for Hg2+ and its on-site applications

WOS:000739252600001A novel multiple-target chemoprobe (E)-N′-((9-pentyl-9H-carbazole-3-yl)methylene)thiophene-2-carbohydrazide (CTH) was designed, successfully synthesized and employed for the detection of Hg2+ and Fe3+ ions as off–on fluorometric and colorimetric responses, respectively, in H2O/DMF (10/90, v/v, Britton–Robinson buffer, pH 7) medium. The chemoprobe CTH demonstrated high sensitivity towards Hg2+ and Fe3+, among wide range of competitive cations with low recognition limits of 5.1 nM and 5.89 µM, respectively. The complexes of the chemoprobe CTH were synthesized and characterized by 1H-NMR titration, FT-IR and MALDI-TOF MS techniques, which confirmed the binding stoichiometries and the possible sensing mechanisms, were suggested based on the hydrolysis reaction of C=N group. The practical utility of the chemoprobe CTH was revealed in quantification of the trace amounts of Hg2+ and Fe3+ in water samples. Also, a silica-coated test paper was used for the fluorescent monitoring of Hg2+, providing a novel approach for the quantitative and on-site detection in real samples. More excitingly, a smartphone application was employed for the visual detection of Fe3+ by recognizing the RGB (red/green/blue) of the chemoprobe CTH solution. Graphical abstract: [Figure not available: see fulltext.]

A rhodamine based nanosensor platform for Hg2+ sensing in near–perfect aqueous medium: Smartphone, test strip and real sample applications

WOS:000696967800003Herein, a rhodamine based nanosensor platform (RHD–NPs) was designed and prepared for the sensing of Hg2+ in the near–perfect aqueous medium (v/v, 0.01/99.99, acetone/water). The structure, aqueous stability, surface charge and particle size of RHD–NPs were analyzed by using zeta particle sizer, scanning electron microscopy (SEM) and UV–Vis spectrophotometry. The spherical shaped morphology of RHD–NPs has 61.4 nm particule size. The interaction ability of RHD–NPs towards various heavy metal ions was evaluated with UV–Vis and fluorescence spectroscopies. After the transferring of Hg2+ to RHD–NPs, a new absorption band at 562 nm was observed due to the ring–opening mechanism of rhodamine structure. The remarkable emission enhancement at 582 nm was observed through the adding of Hg2+ because of chelation–enhanced fluorescence (CHEF) and aggregation–induced enhanced emission (AIEE) phenomena. RHD–NPs nanosensor system showed good selectivity for Hg2+ monitoring with a nanomolar–level detection limit of 6.56 nM. The binding constant of RHD–NPs with Hg2+ was determined to be 10.06 × 103 M−1 based on the Benesi–Hildebrand graph and a maximum value of Job's graph was about 0.5 ratio (1:1) between RHD–NPs and Hg2+.The smartphone–based technique revealed an outstanding potential of the RHD–NPs platform for the sensing of Hg2+ without further device. A visual colorimetric strip based on papers with excellent selectivity towards Hg2+ without interfering competition ions, was produced with the white–to–pink color signal change. The RHD–NPs was also employed for the quantitative determination and real–time monitoring of Hg2+ in real samples

An ultrasensitive ″OFF–ON″ fluorogenic sensor based on thiazole derivative for Zn2+: Food supplement, water and bio–imaging applications

WOS:000687587600002In the present study, the design of a novel turn–on fluorescent probe ((E)–5–methoxy–4–((thiazol–2–ylimino)methyl)benzene–1,3–diol) (TBD) was reported. TBD showed an excellent fluorogenic response (λex = 420 nm, λem = 530 nm) to sense Zn2+ in HEPES buffer/MeCN (5/95, v/v; pH = 7.4) media. The quantum (Φ) yield of the probe TBD increased importantly with Zn2+ and was calculated for TBD (Φ = 0.073) and TBD–Zn2+ complex (Φ = 0.78). The LOD and binding constant (Ka) of TBD were 1.29 nM and 1.102 × 106 M−1, respectively. The sensing process of TBD toward Zn2+ (1:1) was verified by the Job's plot, MALDI–TOF–MS, and 1H NMR titration studies. The ''off–on'' fluorogenic response of TBD was qualified to the photo–induced electron transfer (PET) process. The experimental outcomes were also verified by theoretical DFT studies. Furthermore, TBD had been successfully utilized to detect Zn2+ in food supplement products, drinkable water samples and living–cells for on–site analysis

A novel phenolphthalein-based fluorescent sensor for Al3+ sensing in drinking water and herbal tea samples

WOS:000576952000018PubMed ID: 32781355In this study, 3,3-bis(4-hydroxy-3-((E)-((4-hydroxyphenyl)imino)methyl) phenyl)isobenzofuran-1(3H)-one (HMBP) was designed as a "turn-on" fluorogenic chemosensor to detect Al3+. Studies were performed in C2H5OH-HEPES (v/v, 9/1, pH 7.0) media at lambda(em) = 475 nm. The LOD value was found to be 0.113 mu M. The stoichiometric ratio of HMBP-Al3+ was determined as 1:2 by Job's plot and ESI-MS as well as H-1 NMR titration. The binding constant of chemosensor HMBP with Al3+ from the Benesi-Hildebrand equation was determined to be 1.21 x 10(8) M-1 . The quantum (Phi) yields were obtained as 0.040 and 0.775 for the chemosensor HMBP and HMBP-Al3+ , respectively. The response of the chemosensor HMBP towards Al3+ was attributed to the strategies of blocking the photo-induced electron transfer (PET) and C=N isomerisation mechanisms. Finally, the sensing of the chemosensor HMBP for the determination of Al3+ in real food samples, drinking waters and herbal teas, were employed.The authors are grateful to the KMU for their support (project number 06-M-20) and providing the Gaussian-09 database and GaussView-5.0.8 software