197 research outputs found

    Anticancer activity of Sargassum oligocystum water extract against human cancer cell lines

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    Background and Objectives: Antitumor drug resistance and side effects of antitumor compounds are the most common problems in medicine. Therefore, finding new antitumor agents with low side effects could be interesting. This study was designed to assay antitumor activity of the extract from brown alga Sargassum oligocystum, gathered from Persian Gulf seashore, against K562 and Daudi human cancer cell lines. Materials and Methods: The research was performed as an in vitro study. The effect of the alga extract on proliferation of cell lines were measured by two methods: MTT assay and trypan blue exclusion test. Results and Conclusion: The most effective antitumor activity has been shown at concentrations 500 ΞΌg/ml and 400 ΞΌg/ml of the alga extract against Daudi and K562 cell lines, respectively. The results showed that the extracts of brown alga Sargassum oligocystum have remarkable antitumor activity against K562 and Daudi cell lines. It is justified to be suggested for further research such as algal extract fractionation and purification and in vivo studies in order to formulate natural compounds with antitumor activities

    Critical fluctuations and random-anisotropy glass transition in nematic elastomers

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    We carry out a detailed deuterium NMR study of local nematic ordering in polydomain nematic elastomers. This system has a close analogy to the random-anisotropy spin glass. We find that, in spite of the quadrupolar nematic symmetry in 3-dimensions requiring a first-order transition, the order parameter in the quenched ``nematic glass'' emerges via a continuous phase transition. In addition, by a careful analysis of the NMR line shape, we deduce that the local director fluctuations grow in a critical manner around the transition point. This could be the experimental evidence for the Aizenman-Wehr theorem about the quenched impurities changing the order of discontinuous transition

    In vitro antitumor activity of Gracilaria corticata (a red alga) against Jurkat and molt-4 human cancer cell lines

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    Gracilaria corticata is a red alga which can be collected from many sea coasts around the world such as China, India, Persian Gulf, etc. The Persian Gulf is a unique marine habitat infested with diverse seaweeds. The aim of the present study is to explore anticancer potential of the crude extracts from G. corticata which was collected from the Bushehr coast (South west of Iran). Here, different concentration of the aqueous extract from G. corticata was tested for probable antitumoral activity on Jurkat and molt- 4 human lymphoblastic leukemic cell lines. The cells were treated by different concentration of algal extract and the number of viable cells was determined by trypan blue. Also, cytotoxicity of the extract was evaluated by methyl thiazolyl tetrazolium (MTT) assay. The results showed that 9.336 and 9.726 ΞΌg/ΞΌl of algal extract were the most effective concentrations against Jurkat and molt-4 cells, respectively. The water crude extract of red alga G. corticata had significant anticancer activity and it might be a good candidate for further investigations in order to develop a natural compound as an anticancer agent which can be used for the production of potential anticancer drug and novel pharmaceutical leads.Key words: Gracilaria corticata, anticancer, Jurkat, molt-4

    PraNet: Parallel Reverse Attention Network for Polyp Segmentation

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    Colonoscopy is an effective technique for detecting colorectal polyps, which are highly related to colorectal cancer. In clinical practice, segmenting polyps from colonoscopy images is of great importance since it provides valuable information for diagnosis and surgery. However, accurate polyp segmentation is a challenging task, for two major reasons: (i) the same type of polyps has a diversity of size, color and texture; and (ii) the boundary between a polyp and its surrounding mucosa is not sharp. To address these challenges, we propose a parallel reverse attention network (PraNet) for accurate polyp segmentation in colonoscopy images. Specifically, we first aggregate the features in high-level layers using a parallel partial decoder (PPD). Based on the combined feature, we then generate a global map as the initial guidance area for the following components. In addition, we mine the boundary cues using a reverse attention (RA) module, which is able to establish the relationship between areas and boundary cues. Thanks to the recurrent cooperation mechanism between areas and boundaries, our PraNet is capable of calibrating any misaligned predictions, improving the segmentation accuracy. Quantitative and qualitative evaluations on five challenging datasets across six metrics show that our PraNet improves the segmentation accuracy significantly, and presents a number of advantages in terms of generalizability, and real-time segmentation efficiency.Comment: Accepted to MICCAI 202

    The effect of foliar application of magnetic water and nano-fertilizers on phytochemical and yield characteristics of fennel

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    Environmental factors, especially nutrients, can influence the production of medicinal plants. Thus, the present study assessed the response of some morphological and physiological characteristics of fennel ecotypes to the foliar application (magnetic water, organic and chemical fertilizers). The study was a factorial experiment based on the randomized complete block design, with three replications and 25 treatments at the research farm of the Agricultural and Natural Resources Research and Education Center of West Azerbaijan province, Iran, in the spring and summer of two consecutive years, 2014–2015 and 2015–2016. The first factor was assigned to fennel landraces (Gaziantep, Hamedan, Urmia, Yazd, and Shiraz) and the second factor to the foliar application (nitrogen nano-fertilizer, magnetic water, urea, chicken manure, and the control). Results showed that interaction of fertilizer treatment and landrace increased fresh and dry weight, biological yield, and seed yield significantly. In the first year, the highest fresh weight (166 g) and dry weight (35.5 g) were observed in the Gaziantep landrace fertilized with chicken manure. The highest anethole and fenchone contents (81.75% and 7.92%, respectively) were observed in the landraces treated with chicken manure. Based on the percentages, the Urmia landrace had the highest anethole percentage (83.2%), and the Shiraz landrace had the lowest one (77.5%). The highest fenchone contents (9.61%) and the lowest (2.18%) were observed in the Yazd and Urmia landraces. Due to the positive effect of application of chicken manure on improving the studied traits of fennel, it is recommended to include chicken manure inputs to enhance the efficiency of crops, reduce environmental pollution, and move toward sustainable agriculture

    Identification of a novel type of spacer element required for imprinting in fission yeast

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    Asymmetrical segregation of differentiated sister chromatids is thought to be important for cellular differentiation in higher eukaryotes. Similarly, in fission yeast, cellular differentiation involves the asymmetrical segregation of a chromosomal imprint. This imprint has been shown to consist of two ribonucleotides that are incorporated into the DNA during laggingstrand synthesis in response to a replication pause, but the underlying mechanism remains unknown. Here we present key novel discoveries important for unravelling this process. Our data show that cis-acting sequences within the mat1 cassette mediate pausing of replication forks at the proximity of the imprinting site, and the results suggest that this pause dictates specific priming at the position of imprinting in a sequence-independent manner. Also, we identify a novel type of cis-acting spacer region important for the imprinting process that affects where subsequent primers are put down after the replication fork is released from the pause. Thus, our data suggest that the imprint is formed by ligation of a not-fullyprocessed Okazaki fragment to the subsequent fragment. The presented work addresses how differentiated sister chromatids are established during DNA replication through the involvement of replication barriers

    Automated Analysis of Chest Radiographs for Cystic Fibrosis Scoring

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    We present a framework to analyze chest radiographs for cystic fibro-sis using machine learning methods. We compare the representational power of deep learning features with traditional texture features. Specifically, we respec-tively employ VGG-16 based deep learning features, Tamura and Gabor filter based textural features to represent the cystic fibrosis images. We demonstrate that VGG-16 features perform best, with a maximum agreement of 82%. In ad-dition, due to limited dimensionality, Tamura features for unsegmented images achieve no more than 50% agreement; however, after segmentation, the accuracy of Tamura can reach 78%. In combination with using the deep learning features, we also compare back propagation neural network and sparse coding classifiers to the typical SVM classifier with polynomial kernel function. The result shows that neural network and sparse coding classifiers outperform SVM in most cases. Only with insufficient training samples does SVM demonstrate higher accuracy

    Improving precision for detecting change in the shape of the cornea in patients with keratoconus

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    To investigate a method for precision analysis to discriminate true corneal change from measurement imprecision in keratoconus (KC). Thirty patients with KC and 30 healthy controls were included. Coefficients of repeatability and limits of agreement (LOA) were compared using multiple measurements for inter-observer and inter-device agreement with the Pentacam HR, Orbscan IIz, and Tomey Casia SS-1000. Correlation of repeated measurements was evaluated using a linear mixed effect model (also called random effect model). A formula was derived for the theoretical expected change in precision and compared with measured change. Correlation between measurements from the same eye was small (R = 0.13). The 99.73% LOA (3 SD) of the mean of three measurements, provided better precision than 95% LOA (2 SD) of single cut-off values as expected from statistical theory for uncorrelated measurements for evidence of a significant change in corneal shape in patients with keratoconus. This enabled the determination of cut-off values for the detection of true change in corneal shape. The mean of three repeated measurements will provide better precision when there is minimal correlation. Three (rather than two) standard deviations provides a precise estimate of the LOA within or between observers and can be used as a reliable measure for identifying stage-independent corneal shape changes (progression) in keratoconus

    Absence of CD34 on Murine Skeletal Muscle Satellite Cells Marks a Reversible State of Activation during Acute Injury

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    Background: Skeletal muscle satellite cells are myogenic progenitors that reside on myofiber surface beneath the basal lamina. In recent years satellite cells have been identified and isolated based on their expression of CD34, a sialomucin surface receptor traditionally used as a marker of hematopoietic stem cells. Interestingly, a minority of satellite cells lacking CD34 has been described. Methodology/Principal Findings: In order to elucidate the relationship between CD34+ and CD34- satellite cells we utilized fluorescence-activated cell sorting (FACS) to isolate each population for molecular analysis, culture and transplantation studies. Here we show that unless used in combination with a7 integrin, CD34 alone is inadequate for purifying satellite cells. Furthermore, the absence of CD34 marks a reversible state of activation dependent on muscle injury. Conclusions/Significance: Following acute injury CD34- cells become the major myogenic population whereas the percentage of CD34+ cells remains constant. In turn activated CD34- cells can reverse their activation to maintain the pool of CD34+ reserve cells. Such activation switching and maintenance of reserve pool suggests the satellite cell compartment is tightly regulated during muscle regeneration
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