Red Intensity Research Articles

Down conversion and efficient NIR to visible up-conversion emission analysis in Ho3+/Yb3+ co-doped tellurite glasses

A series of glasses with chemical composition (50−x−y) TeO2–30ZnO–10YF3–10NaF–xHo2O3–yYb2O3 (x=0.5 and y=0.5, 1.0, 3.0, 5.0mol%) were prepared by melt-quenching procedure. The absorption spectra, excitation, down conversion emission spectra, up-conversion (UC) emission spectra and decay time measurements were analyzed. In down conversion, the visible emission transition intensity associated with 5F4→5I8 (547nm), 5F5→5I8 (657nm), and 5F4→5I7 (755nm) of Ho3+ ions decreased with Yb3+ concentration due to the energy transfer (ET) process from Ho3+ to Yb3+ ions. In up-conversion, on exciting with 980nm diode laser beam, we observed a strong green (543nm) and red (657nm) UC emissions, that refers to the energy level transitions; 5F4 (5S2)→5I8 and 5F5→5I8 of Ho3+. The influence of excitation power on UC intensities studies revealed that the population at 5F4 (5S2) and 5F5 levels of Ho3+ ion occurs due to two-photon absorption process associated energy transfer from Yb3+ to Ho3+. The influence of Yb3+ doped concentration on UC was studied, and it is observed that both the green and red UC intensities improved significantly on increasing Yb3+ ions concentration.

Effect of Duration of LED Lighting on Growth, Photosynthesis and Respiration in Lettuce.

Parameters of illumination including the spectra, intensity, and photoperiod play an important role in the cultivation of plants under greenhouse conditions, especially for vegetables such as lettuce. We previously showed that illumination by a combination of red, blue, and white LEDs with a high red light intensity, was optimal for lettuce cultivation; however, the effect of the photoperiod on lettuce cultivation was not investigated. In the current work, we investigated the influence of photoperiod on production (total biomass and dry weight) and parameters of photosynthesis, respiration rate, and relative chlorophyll content in lettuce plants. A 16 h (light):8 h (dark) illumination regime was used as the control. In this work, we investigated the effect of photoperiod on total biomass and dry weight production in lettuce plants as well as on photosynthesis, respiration rate and chlorophyll content. A lighting regime 16:8 h (light:dark) was used as control. A shorter photoperiod (8 h) decreased total biomass and dry weight in lettuce, and this effect was related to the suppression of the linear electron flow caused by the decreasing content of chlorophylls and, therefore, light absorption. A longer photoperiod (24 h) increased the total biomass and dry weight, nevertheless an increase in photosynthetic processes, light absorption by leaves and chlorophyll content was not recorded, nor were differences in respiration rate, thus indicating that changes in photosynthesis and respiration are not necessary conditions for stimulating plant production. A simple model to predict plant production was also developed to address the question of whether increasing the duration of illumination stimulates plant production without inducing changes in photosynthesis and respiration. Our results indicate that increasing the duration of illumination can stimulate dry weight accumulation and that this effect can also be induced using the equal total light integrals for day (i.e., this stimulation can be also caused by increasing the light period while decreasing light intensity). Increasing the duration of illumination is therefore an effective approach to stimulating lettuce production under artificial lighting.

Structural characterization and antimicrobial activity of 2-[4,6-(Cl/CH3/CF3)-benzimidazol-2-yl]-4-(OCH3/Br)-phenols and their Zn(II), Pd(II) and Au(III) complexes

2-[4,6-{Dichloro/dimethyl/bis-(trifluoromethyl)}-benzimidazol-2-yl]-(5-bromo/methoxy)-phenols (HL1 – HL6) and their complexes with ZnCl2, PdCl2 and AuCl3 were synthesized and characterized. The structures of the complexes were confirmed on the basis of elemental analysis, molar conductivity, FT-IR, NMR and fluorescence spectroscopy. Most of the complexes are four-coordinated with a 1:2 M:L ratio and the Au(III) complexes are 1:1 electrolyte whereas the others are non-electrolyte. According to the fluorescence spectra, electronegative substituents such as bromo, chloro, trifluoromethyl and methoxy were found to increase red shift (shifting to higher wavelength). The highest wavelength was observed to belong to HL6 (trifluoromethyl-methoxy derivative) with 531 nm. When compared to the ligands, there is decreasing in the red shift and fluorescence intensity in the spectra of the complexes. In addition, antimicrobial activity of the compounds was evaluated against six bacteria and three fungi. The Au(III) complexes have superior activity against all the bacteria, while the Pd(II) complexes showed higher antifungal activity than the ligands and metal salt.

Viscosity prediction using image processing and supervised learning

The paper implements image processing followed by supervised learning to predict the viscosity of hydrocarbon present at a specific reservoir depth in a heavy oil reservoir located in California, USA. Viscosity is predicted from white-light and UV-light images of side-wall core samples extracted from specific depths along the wellbore. The fluid viscosity primarily ranges from 5 to 600 cP at a temperature of 180 degF. The white-light and UV-light images are available for 680 side-wall core samples. Sobel, Sato, Hessian, LBP, and Multi-Otsu filters extract meaningful features from red, green, and blue pixel intensities of the white-light and UV-light images. The distribution of pixel-wise values for each filtered/raw image is further processed to derive histogram-based features. As a result, 600 features are extracted for each side-wall core sample. Thresholds based on the variance, MI score, F score, and Person’s r are imposed to select the most informative features for the viscosity prediction. Compared to filtered white-light images, raw RGB white-light images have stronger viscosity association. On the contrary, filtered UV-light images have stronger viscosity association as compared to raw RGB UV-light images. Supervised learning is deployed using the resulting features in both regression and classification of target viscosity. For the prediction of continuous-valued viscosity (regression), random forest is the best performer with a mean absolute error of 27 ∓ 3 cP. For the viscosity classification, high-viscosity and low-viscosity samples can be very well detected at a F1 Weighted Score higher than 0.95 and Matthew’s Correlation Score higher than 0.9. Overall, for viscosity prediction, classification is much superior to the regression. The novel image-based viscosity prediction workflow will help lower the cost and improve the precision of laboratory-based viscosity measurements and simultaneously contribute to a high-resolution reservoir model development.

Efficient Quantum Dot Color Conversion Layer with Mixed Spherical/Rod-Shaped Scattering Particles

A quantum dot (QD) color conversion layer (CCL) with mixed-shaped scattering nanoparticles exhibits enhanced light conversion and reduced blue leakage in QD-organic light-emitting diodes (OLEDs). In this study, nontoxic bright red QDs and spherical and rod-shaped zinc oxide (ZnO) nanoparticles were mixed in an ultraviolet-curable resin without aggregation. The mixture of spherical and rod-shaped ZnO nanoparticles enhanced the blue light scattering inside the QD CCL, which results in an increase of the blue absorption by the QDs and a dramatic improvement of the color conversion. Extraction of the converted red light was also attributed to the Mie scattering of the rod-shaped scattering nanoparticles. The QD CCL with 15 wt % mixed-shaped scattering particles showed seven times increase of red intensity and four times decrease of blue intensity compared to that without scattering particles. We fabricated direct coat-type QD-OLEDs and confirmed that the color conversion and output/input efficiencies were improved and the blue leakage was decreased with increasing number of QD CCLs. This method improves the color conversion efficiency without increasing the amount of QDs and reducing the blue leakage without using a color filter.

The gradient distribution of pigment metabolites provided insights into the uneven colouration of pulp in cold-stored blood orange

Pigment accumulation is the material basis for colour formation in blood orange pulp. Regarding colour characterization during cold storage in this study, the red pigment intensity and the chlorophyll content of the fruit were lowest in the peduncle end and highest in the stylar end. Most of the carotenoids and anthocyanins in the peduncle end, equator and stylar end increased during cold storage. The highest carotenoid content was found at the equator, and the lowest carotenoid content was found at the stylar end. Regarding the two principal anthocyanins (C3,6 mg and C3G), the highest content was observed in the stylar end, and the lowest content was found in the peduncle end. The upregulated genes involved in pigment synthesis, such as CHLP, HemF, HemY, MgCh and DVR for chlorophyll synthesis; PDS, ZDS1/2/3, LCYb and CHY-β for carotenoid synthesis, and DFR, ANS, ANR, BZL, 3RT and UFGT for anthocyanin synthesis, might explain the chlorophyll, carotenoid and anthocyanin accumulation that occurs during cold storage.

Grafting Technology with Locally Selected Eggplant Rootstocks for Improvement in Tomato Performance

Grafting technology is one of the best alternatives to mitigate limiting factors to tomato production (Solanum lycopersicum L). The study aimed to assess grafting combinations of tomato scions and rootstocks of eggplant (S. melongena L.) varieties Gelatik, EG203 line, and Takokak (S. torvum Sw.). Tomato varieties Cervo, Karina, and Timoty were used as scions. The grafted Cervo and Timoty yielded 30% more than non-grafted plants. The results show that grafted tomatoes suppressed disease incidence by more than 20%. The suppression resulted in higher shelf-life capacity and total dissolved solids of more than 10%, red colour intensity (a+) of more than 16%, lycopene content, fruit hardness level of more than 20%, and reduced water content by more than 1%. Vitamin C content was not affected by grafting technology. There is the potential for economic performance in the market for producers and consumers. Grafting technology in tomatoes using eggplants as rootstock could reduce disease incidence and improve agronomic aspects, product quality, and nutrient contents. Different cultivars of scions and rootstock showed different responses. Grafting technology could be disseminated to farmers for economic advantages during the off-season.

Extratos naturais na marinação de filés de peito de frango

ABSTRACT: This study evaluated the effects of natural extracts on chicken breast fillet marinades regarding the physicochemical properties, oxidative stability, and the Staphylococcus aureus and Escherichia coli inhibition during 21 days of storage. Chicken breast fillets (Pectoralis major) (128 units) purchased in a local market, were used, allocated in a completely randomized block design, in a 4 x 4 factorial scheme (antioxidant x storage time), totalling 16 treatments with eight replicates. The TBARS and the pH values were not influenced by the analyzed factors. For the color results, the values of L* and b* were lower in the marinated chicken breast fillets with basil and BHT, respectively. When assessing the effect of storage time, an increase in oxidation was observed up to 21 days of storage. For pH, a quadratic decrease after storage with an increase in the pH value from the 11th day of storage was observed. In the color results, there was a linear decrease in the L* value during the storage period and in the value of b* a quadratic effect was observed with a reduction of this intensity up to 21 days of storage. In relation to the value of a*, a quadratic effect with an increase in the red intensity from the 7 days of storage was observed. For the counting of the S. aureus, the treatments presented 102 CFU/g up to 14 days, except for the basil which exceeded the limit established by the legislation at 14 days.

An Automated cDNA Microarray Image Analysis for the Determination of Gene Expression Ratios.

This paper proposes a fully automated technique for cDNA microarray image analysis. Initially, an effective preprocessing stage combined with gridding is built to get the individual spot regions of images. Current work begins with the proposal of a new rule to get the foreground (spot) and background regions in the spot blocks, which uses TV-L1 image denoising, spot block binarization, and finds the most accurate spot label by measuring the centroid differences of labelled regions in the block with that of the spot block centroid. The credibility of the segmentation rule on real images is evaluated by metrics: mean absolute error (MAE) and coefficient of variation (CV) and on synthetic images by metrics: probability of error (PE) and discrepancy distance (DD). The performance values on real and synthetic datasets reveal better results than the competitive methods. After the segmentation, prior to the spot intensity extraction, background intensity correction and flagging of noisy spots are executed. Using the lowess method, intensities are normalized, and gene expression ratios are determined. To comprehend the linearities of red and green intensities and to discern up and down-regulated genes (abnormal), fold-change factor, scatter and box plots are also used to represent the gene expression levels.

Enhanced bright green luminescence from GdOF:Ho3+ up-conversion phosphor via Yb3+ doping

In this paper, a series of GdOF-based green phosphors doped with Ho3+ and Yb3+ ions was prepared by a simple co-precipitation method. The crystal structures and optical properties were investigated in detail. The intensity of the emission of GdOF:Yb3+,Ho3+ phosphors is enhanced by the effective energy transfer from Yb3+ to Ho3+, and the optimal luminescence is achieved with the Ho3+ doping amount of 0.1 mol% as well as Yb3+ doping amount of 5 mol%. Tunable UC emission of samples is achieved by adjusting the doping concentration of Ho3+ or Yb3+. The purity of the green UC emission is further improved by enhancing the excitation pumping power. In addition, logarithmic functions of green, red and near-infrared radiation intensities were calculated versus logarithmic function of pump power for further study. A possible UC luminescence mechanism between Yb3+ and Ho3+ is discussed based on power-dependent UC luminescence spectrum and decay lifetimes. These results suggest that GdOF:Yb3+,Ho3+ phosphors with bright and high-purity green UC emission have potential applications in the fields of bioimaging, display and illumination.

On Reducing ShuffleNets’ Block for Mobile-based Breast Cancer Detection Using Thermogram: Performance Evaluation

In this paper, we proposed a reduced-block-Shufflenet (RB-ShuffleNet) for thermal breast cancer detection. RB-ShuffleNet is a modification of Shufflenet obtained by reducing blocks from the original architecture. The images for training and testing were obtained from Database for Mastology Research (DMR). First, we detected and cropped the image based on the region of interest (ROI), in which the ROI is determined by using the red intensity profile. Then, the ROI images were trained using RB-ShuffleNets. In the experiments, we built eight architectures, based on ShuffleNet, each with a different number of reduced blocks. The result showed that RB-Shufflenet with four reduced blocks had fewer than 50% of the learning parameters of the original Shufflenet, without compromising its performance. The RB-ShuffleNet with up to four reduced blocks could achieve 100% testing accuracy. Furthermore, The RB-ShuffleNets performed better than MobileNetV2 and resulted in higher accuracy when fed with ROI images. Due to its light structure and good performance, we recommend RB-ShuffleNet as mobile-based CNN model which is preferable to implement in breast cancer detection.

Synthesis of Rare-Earth-Doped Strontium Tungstate Phosphor at Room Temperature and Applied Flexible Composite.

In this study, we successfully synthesized rare-earth-doped crystalline SrWO4 at room temperature by co-precipitation. The results from the X-ray diffraction analysis showed a main diffraction peak related to the (112) plane. Phosphors doped with either Dy3+ or Sm3+ ions showed strong light absorption in the UV region and blue-yellow and red light emission. To synthesize a white light phosphor, Dy3+ and Sm3+ ions were co-doped to produce a SrWO4:[Sm3+]/[Dy3+] phosphor. When the Sm3+ ion concentration was increased and the Dy3+ concentration was maintained, the red light intensity increased while the blue-yellow light intensity decreased. The composites were combined with polydimethylsiloxane (PDMS), and a flexible composite material was fabricated. The composite exhibited various luminescence properties under UV and visible light, which suggested its potential for use as an LED color filter.

Cucurbitacin B-, E-, and I-Induced Browning of White Adipocytes Is Promoted by the Inhibition of Phospholipase D2.

The mechanism of white adipose tissue browning is not well understood; however, naturally occurring compounds are known to play a positive role. The effects of cucurbitacins B, E, and I on the browning of mature white adipocytes were investigated. First, the cell viability exhibited by cucurbitacins B, E, and I in pre- and mature adipocytes was verified. Cucurbitacins B, E, and I had no effect on cell viability in pre- and mature adipocytes at concentrations up to 300 nM. To investigate the characteristics of representative beige adipocytes, the formation and morphology of cucurbitacin B, E, and I lipid droplets were verified. The total lipid droplet surface area, maximum Feret diameter, and total Nile red staining intensity of cucurbitacin B-, E-, and I-treated adipocytes were lower than those of mature white adipocytes. Furthermore, treatment of white mature adipocytes with cucurbitacin B, E, and I led to the formation of several small lipid droplets that are readily available for energy expenditure. We evaluated the effect of cucurbitacins B, E, and I on the expression of representative browning markers UCP1, PGC1a, and PRDM16, which participate in the browning of white adipose tissue. Cucurbitacins B, E, and I increased the mRNA and protein expression levels of UCP1, PGC1a, and PRDM16 in a concentration-dependent manner. To promote energy consumption by beige adipocytes, active mitochondrial biogenesis is essential. Next, we investigated the effects of cucurbitacin B, E, and I on mitochondrial biogenesis in mature adipocytes. Mitochondrial mass increased when mature adipocytes were treated with cucurbitacin B, E, and I. The degree of cucurbitacin B-, E- and I-induced transformation of white adipocytes into beige adipocytes was in the order of Cu E > Cu B > Cu I. To verify the effect of phospholipase D2 on the browning of white adipocytes, CAY10594—a PLD2 pharmacological inhibitor, and a knockdown system were used. PLD2 inhibition and knockdown improved the expression levels of UCP1, PGC1a, and PRDM16. In addition, PLD2 inhibition and knockdown in mature white adipocytes promoted mitochondrial biosynthesis. The effect of PLD2 inhibition and knockdown on promoting browning of white adipocytes significantly increased when Cu B, Cu E, and Cu I were co-treated. These data indicate that mature white adipocytes’ beige properties were induced by cucurbitacins B, E, and I. These effects became more potent by the inhibition of PLD2. These findings provide a model for determining anti-obesity agents that induce browning and increase energy expenditure in mature white adipocytes.

The red/blue light ratios from light-emitting diodes affect growth and flower quality of Hippeastrum hybridum 'Red Lion'.

Light quality strongly impacts the growth and flower quality of ornamental plants. The optimum light quality for the growth and flowering of Hippeastrum remains to be validated. In the present study, we investigated the effect of the red/blue light ratio of LEDs on the growth and flowering quality of H. hybrid 'Red Lion'. Two LEDs with red/blue light ratio of 1:9 (R10B90) and 9:1 (R90B10) were designed. LEDs of white light were the control. In the earlier vegetative and reproductive growth phase, R90B10 increased the biomass of the bulbs, leaves, and flowers. Compared with the control and R10B90 group, R90B10 LEDs delayed flowering by 2.30d and 3.26d, respectively. Based on chlorophyll contents, photosynthetic capacity, chlorophyll fluorescence parameters, and carbohydrate contents, the photosynthesis rate was higher in the R10B90 group. Optimal red and blue light intensity promoted the accumulation of carbohydrates and early flowering and prolonged the flowering period of H. hybrid. Microscopic analysis showed that stomatal density was high, and the number of chloroplasts was large in the R10B90 treatment group, which enhanced photosynthesis. Particularly, R10B90 promoted the expression of seven key genes related to chlorophyll synthesis. R10B90 also promoted early overexpression of the HpCOL gene that promotes early flowering. Thus, higher blue light and 10% red light intensities promote early and extended flowering, while higher red light and 10% blue light promote vegetative plant growth but delay flowering.

Optical monitoring and treatment of breast cancer by a tumor hypoxia-activated multi-functional fluorescent sensor

Breast cancer is one of the most common cancers and a leading cause of death in women. Caused by the rapid growth, tumors show marked areas of hypoxia that play an important role in cancer progression and metastasis. We developed a near-infrared multifunctional azo-derivative, L4OD, to target the hypoxic environment of tumors. The release of fluorescent signals and lead compounds following its reaction with cytochrome P450 reductase allowed simultaneous optical detection and inhibited breast cancer tumor growth. The specificity of L4OD for cytochrome P450 reductase was confirmed in vitro through its reactions with tin chloride and rat liver microsomes. In HepG2 cells pre-treated with different oxygen concentrations (1%, 10%, and 21%) for 12 h, the red fluorescent intensity in the cells gradually increased as the oxygen concentration decreased, showing that L4OD can be used to image cytochrome P450 reductase enrichment and to monitor the associated hypoxic environment in cells. Using a mouse tumor xenograft model, we used L4OD successfully for in situ optical detection and tumor suppression in hypoxic regions of breast cancer tumors, with a high inhibition rate of 45%. These results indicate the high performance of L4OD for monitoring and therapy of breast cancer and the potential for further clinical application.

Geographical features of Tulipa suaveolens Roth (Liliaceae, Magnoliophyta) distribution by flower color across its European range

The range of the polychromous Tulipa suaveolens Roth comprises almost the whole Ponto-Caspian Steppe, from the south-east of Ukraine to western Kazakhstan. High variation in flower color is a unique feature of this species, but features of its geographical distribution remain unclear. We studied T. suaveolens tepal color variation in 56 natural populations across the European range. Tepal colors were detected from digital images using the Lab color model with two chromatic components, a (red color intensity) and b (yellow color intensity). A conclusion was made that, throughout the European range, an obvious T. suaveolens flower color gradient is expressed in the direction from the south-west to the north-east, along which the red chromatic component intensity decreases. A similar gradient is observed when the height above mean sea level increases. The chromatic component a was shown to have a spatial autocorrelation and to depend on the long-term bioclimatic environmental parameters, temperature and precipitation. Thus, the identified geographical trends in the T. suaveolens flower color distribution across the studied part of its range are a consequence of natural selection caused by these two abiotic factors.

Effect of different mixed light-emitting diode light wavelengths on CO2 absorption from biogas and nutrient removal from biogas slurry by microalgae and fungi induced using strigolactone and endophytic bacteria.

In this study, biogas and biogas slurry were simultaneously treated using two symbiotic systems: Chlorella vulgaris-Ganoderma lucidum-S395-2 (endophytic bacteria) and Scenedesmus obliquus-G. lucidum-S395-2. The influence of different mixed illumination (red and blue) intensity ratios on the algal symbionts' extracellular carbonic anhydrase activities was investigated, as well as the rates of microalgal growth and photosynthesis. The treatment performance was simultaneously assessed in terms of the efficiency of organic matter or nutrient removal and the level of CO2 absorption. The results indicated that red-blue light combinations with an intensity ratio of 5:5 were optimal. When comparing the performance of the two symbiotic systems, the C. vulgaris-G. lucidum-S395-2 symbiont co-culture system achieved significantly improved photosynthetic rates, biomass growth, and treatment effects. Under the optimal treatment conditions, the organic matter and nutrient removal rates were 81.06% ± 7.06% for chemical oxygen demand, 82.32% ± 7.18% for total nitrogen, and 82.98% ± 7.26% for total phosphorus. In addition, the rate of CO2 removal from biogas was 63.38% ± 5.35%. PRACTITIONER POINTS: The red and blue light intensity ratio of 5:5 showed the best removal performance. C. vulgaris-G. lucidum-S395-2 system obtained the best photosynthetic performance. The carbonic anhydrase activity had positive effects on CO2 removal performance.

Evaluation of the Effectiveness of Different LED Irradiators When Growing Red Mustard (Brassica juncea L.) in Indoor Farming

Investigation is devoted to the optimization of light spectrum and intensity used for red mustard growing. Notably, most of the studies devoted to red mustard growing were conducted on micro-greens, which is not enough for the development of methods and recommendations for making the right choices about the irradiation parameters for full-cycle cultivation. In this study, we tested four models of LED with different ratios of blue, green red and far red radiation intensity: 12:20:63:5; 15:30:49:6; 30:1:68:1, in two values of photon flux density (PFD)—120 and 180 µmol m−2 s−1—to determine the most effective combination for red mustard growing. The study was conducted in a container-type climate chamber, where the red leaf mustard was cultivated in hydroponics. On the 30th day of cultivation, the plant’s morphological, biochemical and chlorophyll fluorescence parameters, and reflection coefficients were recorded. The results indicated that the PFD 120 µmol m−2 s−1 had a worse effect on both mustard leaf biomass accumulation and nitrate concentration (13–30% higher) in the plants. The best lighting option for growing red mustard was the blue–red spectrum, as the most efficient in terms of converting electricity into biomass (77 Wth/g). This light spectrum contributes to plant development with a larger leaf area (60%) and a fresh mass (54%) compared with the control, which has a maximum similarity in spectrum percentage to the sunlight spectrum. The presence of green and far red radiation with the blue–red light spectrum in various proportions at the same level of PFD had a negative effect on plant fresh mass, leaf surface area and photosynthetic activity. The obtained results could be useful for lighting parameters’ optimization when growing red mustard in urban farms.

Modification of Cotton Fabric with Molecularly Imprinted Polymer-Coated Carbon Dots as a Sensor for 17 α-methyltestosterone.

Molecularly imprinted polymers@ethylenediamine-modified carbon dots grafted on cotton fabrics (MIPs@EDA-CDs/CF) and smartphone-based fluorescence image analysis were proposed and used for the first time for the detection of 17 α-methyltestosterone (MT). The EDA-CDs were synthesized and grafted on cotton fabric before coating with the MIPs. The MIPs were synthesized using the MT as a template molecule, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and azobisisobutyronitrile (AIBN) as an initiator. The MIPs@EDA-CDs/CF were characterized using FTIR, SEM-EDS, and RGB fluorescence imaging. The fluorescence images were also taken using a smartphone and the ImageJ program was used for RGB measurement. The Δ red intensity was linearly proportional to MT concentration in the range of 100 to 1000 μg/L (R2 = 0.999) with a detection limit of 44.4 μg/L and quantification limit of 134 μg/L. The MIPs@EDA-CDs/CF could be stored at 4 °C for a few weeks and could be reused twice. The proposed method could apply for the specific determination of MT in water and sediment samples along with satisfactory recoveries of 96-104% and an acceptable relative standard deviation of 1-6% at the ppb level.

Determination of Clonogenic Radiosensitivity of HeLa Cells in Early and Late G1 Phases.

Using a fluorescent ubiquitination-based cell cycle indicator (Fucci), we recently reported that post irradiation of HeLa cells, micronuclei frequency increased in the early G1 phase in comparison with that in the late G1 phase. This is inconsistent with the results of well-recognized studies that used clonogenic assays. In this study, we determined radiosensitivity of the cells using a clonogenic assay by making the best use of the Fucci property, while simultaneously characterizing cell cycle kinetics and DNA damage responses. Early and late G1 phase cell fractions were isolated using a cell sorter by exploiting the different red fluorescence intensities of Fucci. Radiosensitivity was determined by the colony formation assay. Time-lapse imaging and immunostaining were performed to analyze cell cycle kinetics and DNA damage. Late G1 cells were more radioresistant than early G1 cells. Cells irradiated in the early and late G1 phases induced G2 arrest, while the latter demonstrated a significantly longer duration of G2 arrest. This difference became more evident as the radiation dose increased. Furthermore, 16 h after irradiation, a greater number of γH2AX foci remained in cells irradiated in the early G1 phase than in those irradiated in the late G1 phase. HeLa cells in the late G1 phase are more radioresistant than those in the early G1 phase, presumably because DNA damage is efficiently repaired during a longer G2 arrest in late G1 cells.