161 research outputs found

    Measurement of the high energy γ\gamma-rays from heavy ion reactions using \v{C}erenkov detector

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    The energetic bremsstrahlung photons up to 100 MeV produced in heavy ion collisions can be used as a sensitive probe to the short range correlation in atomic nuclei. The energy of the γ\gamma-rays can be measured by collecting the \v{C}erenkov light in medium induced by the fast electrons generated in Compton scattering or electromagnetic shower of the incident γ\gamma ray. Two types of detectors, based on pure water and lead glass as the sensitive material respectively, are designed for the above purpose. The γ\gamma response and optical photon propagation in detectors have been simulated based on the electromagnetic and optical processes in Geant4. The inherent energy resolution of 0.022+0.51/Eγ1/20.022+0.51/E_{\gamma}^{1/2} for water and 0.002+0.45/Eγ1/20.002+0.45/E_{\gamma}^{1/2} for lead glass are obtained. The geometry size of lead glass and water are optimized at 30×30×3030\times 30 \times 30 cm3^3 and 60×60×12060\times 60 \times 120 cm3^3, respectively, for detecting high energy γ\gamma-rays at 160 MeV. Hough transform method has been applied to reconstruct the direction of the incident γ\gamma-rays, giving the ability to distinguish experimentally the high-energy γ\gamma rays produced in the reactions on the target from the random background cosmic ray muons

    GraphPrompt: Biomedical Entity Normalization Using Graph-based Prompt Templates

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    Biomedical entity normalization unifies the language across biomedical experiments and studies, and further enables us to obtain a holistic view of life sciences. Current approaches mainly study the normalization of more standardized entities such as diseases and drugs, while disregarding the more ambiguous but crucial entities such as pathways, functions and cell types, hindering their real-world applications. To achieve biomedical entity normalization on these under-explored entities, we first introduce an expert-curated dataset OBO-syn encompassing 70 different types of entities and 2 million curated entity-synonym pairs. To utilize the unique graph structure in this dataset, we propose GraphPrompt, a prompt-based learning approach that creates prompt templates according to the graphs. GraphPrompt obtained 41.0% and 29.9% improvement on zero-shot and few-shot settings respectively, indicating the effectiveness of these graph-based prompt templates. We envision that our method GraphPrompt and OBO-syn dataset can be broadly applied to graph-based NLP tasks, and serve as the basis for analyzing diverse and accumulating biomedical data.Comment: 12 page

    Association between Single Nucleotide Polymorphisms in SIRT1 and SIRT2 Loci and Growth in Tibetan Sheep

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    Silent information regulator 1 and 2 (SIRT1, 2) were NAD+-dependent histone or non-histone deacetylase, which emerged as key metabolic sensors in several tissues of mammals. In the present study, the search for polymorphisms within the ovine SIRT1 and SIRT2 loci as well as association analyses between SNPs and growth-related traits were performed in Tibetan sheep. To determine the expression pattern of SIRT1 and SIRT2 genes in Tibetan sheep, the quantitative real-time polymerase chain reaction (qPCR) analysis revealed that those two genes were widely expressed in diverse tissues. Expression of SIRT1 was less in abomasum of lamb, whereas it was greater in duodenum within adult stage. In the case of SIRT2, the greatest expression was observed in reticulum (lamb) and in muscle (adult), whereas the least expression was in liver for lamb and in kidney for adult animals. The association analysis demonstrated that g.3148 C \u3e T polymorphism of SIRT1 affected heart girth (p = 0.002). The g.8074 T \u3e A SNP of SIRT2 had a significant correlation with body weight (p = 0.011) and body length (p = 0.008). These findings suggested that the SIRT1 and SIRT2 polymorphism was involved in growth-related traits in Tibetan sheep, which may be considered to be genetic markers for improving the growth traits of Tibetan sheep

    Smart optically induced nonlinear photonic crystals for frequency conversion and control

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    We extend the functionality of nonlinear photonic crystals by fabricating a structure combining a few individual optical transformations in second harmonic generation. In particular, we employed all-optical spontaneous polarization reversal in ferroelectrics to create nonlinear holograms with curved fork-like spatial modulation of nonlinearity for the generation of second harmonic optical vortices. The curved fork-like structure represents a combination of a standard vortex harmonic generator (fork structure) and an axicon, thereby allowing us to realize the second harmonic "perfect vortices" whose diameter remains constant independently of their topological charge.This work was supported by the Qatar National Research Fund (Grant No. NPRP 12S-0205-190047) and Australian Research Council

    Ultrasound microbubble-mediated delivery of the siRNAs targeting MDR1 reduces drug resistance of yolk sac carcinoma L2 cells

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    <p>Abstract</p> <p>Background</p> <p>MDR1 gene encoding P-glycoprotein is an ATP-dependent drug efflux transporter and related to drug resistance of yolk sac carcinoma. Ultrasound microbubble-mediated delivery has been used as a novel and effective gene delivery method. We hypothesize that small interfering RNA (siRNA) targeting MDR1 gene (siMDR1) delivery with microbubble and ultrasound can down-regulate MDR1 expression and improve responsiveness to chemotherapeutic drugs for yolk sac carcinoma <it>in vitro</it>.</p> <p>Methods</p> <p>Retroviral knockdown vector pSEB-siMDR1s containing specific siRNA sites targeting rat MDR1 coding region were constructed and sequence verified. The resultant pSEB-siMDR1 plasmids DNA were encapsulated with lipid microbubble and the DNA release were triggered by ultrasound when added to culture cells. GFP positive cells were counted by flow cytometry to determine transfection efficiency. Quantitative real-time PCR and western blot were performed to determine the mRNA and protein expression of MDR1. P-glycoprotein function and drug sensitivity were analyzed by Daunorubicin accumulation and MTT assays.</p> <p>Results</p> <p>Transfection efficiency of pSEB-siMDR1 DNA was significantly increased by ultrasound microbubble-mediated delivery in rat yolk sac carcinoma L2 (L2-RYC) cells. Ultrasound microbubble-mediated siMDR1s delivery effectively inhibited MDR1 expression at both mRNA and protein levels and decreased P-glycoprotein function. Silencing MDR1 led to decreased cell viability and IC<sub>50 </sub>of Vincristine and Dactinomycin.</p> <p>Conclusions</p> <p>Our results demonstrated that ultrasound microbubble-mediated delivery of MDR1 siRNA was safe and effective in L2-RYC cells. MDR1 silencing led to decreased P-glycoprotein activity and drug resistance of L2-RYC cells, which may be explored as a novel approach of combined gene and chemotherapy for yolk sac carcinoma.</p

    Semi-Unsupervised Lifelong Learning for Sentiment Classification: Less Manual Data Annotation and More Self-Studying

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    Lifelong machine learning is a novel machine learning paradigm which can continually accumulate knowledge during learning. The knowledge extracting and reusing abilities enable the lifelong machine learning to solve the related problems. The traditional approaches like Na\"ive Bayes and some neural network based approaches only aim to achieve the best performance upon a single task. Unlike them, the lifelong machine learning in this paper focuses on how to accumulate knowledge during learning and leverage them for further tasks. Meanwhile, the demand for labelled data for training also is significantly decreased with the knowledge reusing. This paper suggests that the aim of the lifelong learning is to use less labelled data and computational cost to achieve the performance as well as or even better than the supervised learning

    EFFECTS OF CIJI HUA’AI BAOSHENG GRANULE FORMULA (CHBGF) ON LIFE TIME, PATHOLOGY, PERIPHERAL BLOOD CELLS OF TUMOR CHEMOTHERAPY MODEL MOUSE WITH H22 HEPATOMA CARCINOMA CELLS

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    Background: Ciji Hua’ai Baosheng Granule Formula (CHBGF) is a traditional Chinese empirical formula that can help the tumor patients who have received chemotherapy antagonize the toxin and side-effects so as to improve and prolong the life. This study is to evaluate the effects of CHBGF on improving life quality in terms of survival time, pathology of tumor tissue and ameliorating peripheral blood cells in mouse chemotherapy model with subcutaneous transplanted tumor or ascitic tumor of H22 hepatoma carcinoma cells at an overall level. Materials and Methods: 71 mice among the 92 Kunming mice were injected subcutaneously into the right anterior armpit with H22 hepatoma carcinoma cells, after 7 days, which had formed tumors and were used peritoneal injection of Cytoxan (CTX) (200mg/kg) to establish the mouse chemotherapy model with transplanted tumor, and then which were commensurately divided into 8 groups by random digits table. 21 mice were injected into peritoneal cavity to use CTX and the same method to establish the model. The groups for evaluating the effects on the survival time were the model, CHBGF and positive control group respectively with 7 mice in each group. The groups for evaluating the effects on anti-cancer were the model group, three treatment groups and positive control group with 10 mice in each group. The survival-time-observing groups were given intragastric administration of normal saline, CHBGF (64g/kg) once a day, and peritoneal injection of 5-Fluorouracil (25mg/kg) once every other day respectively. The survival time of each group was observed. The five anti-cancer-observing groups were given intragastric administration of normal saline, CHBGF (64g/kg, 32g/kg and 16g/kg) once a day, and peritoneal injection of 5-Fluorouracil (25mg/kg) once every other day respectively. After treatment for 21 days, the transplanted tumors were peeled off. Blood was collected through pricking eyeball and analyzed by hematology analyzer. And postchemotherapy transplanted tumor inhibition ratios were calculated. Pathological changes of tumor tissues and blood smears were observed with light microscope. Results: The life prolonging rate of CHBGF (64g/kg) group with transplanted tumor is 20.14%, and their survival time was longer than that of the 5-Fluorouracil group (
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