134 research outputs found

    A Disposable Organophosphorus Pesticides Enzyme Biosensor Based on Magnetic Composite Nano-Particles Modified Screen Printed Carbon Electrode

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    A disposable organophosphorus pesticides (OPs) enzyme biosensor based on magnetic composite nanoparticle-modified screen printed carbon electrodes (SPCE) has been developed. Firstly, an acetylcholinesterase (AChE)-coated Fe3O4/Au (GMP) magnetic nanoparticulate (GMP-AChE) was synthesized. Then, GMP-AChE was absorbed on the surface of a SPCE modified by carbon nanotubes (CNTs)/nano-ZrO2/prussian blue (PB)/Nafion (Nf) composite membrane by an external magnetic field. Thus, the biosensor (SPCE│CNTs/ZrO2/PB/Nf│GMP-AChE) for OPs was fabricated. The surface of the biosensor was characterized by scanning electron micrography (SEM) and X-ray fluorescence spectrometery (XRFS) and its electrochemical properties were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The degree of inhibition (A%) of the AChE by OPs was determined by measuring the reduction current of the PB generated by the AChE-catalyzed hydrolysis of acetylthiocholine (ATCh). In pH = 7.5 KNO3 solution, the A was related linearly to the concentration of dimethoate in the range from 1.0 × 10−3–10 ng·mL−1 with a detection limit of 5.6 × 10−4 ng·mL−1. The recovery rates in Chinese cabbage exhibited a range of 88%–105%. The results were consistent with the standard gas chromatography (GC) method. Compared with other enzyme biosensors the proposed biosensor exhibited high sensitivity, good selectivity with disposable, low consumption of sample. In particular its surface can be easily renewed by removal of the magnet. The convenient, fast and sensitive voltammetric measurement opens new opportunities for OPs analysis

    Docetaxel-Loaded Pluronic P123 Polymeric Micelles: in Vitro and in Vivo Evaluation

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    In this work, novel docetaxel (DTX) -loaded Tween 80-free Pluronic P123 (P123) micelles with improved therapeutic effect were developed. The freeze-dried DTX-loaded P123 micelles (DTX-micelles) were analyzed by HPLC, TEM and DLS to determine the DTX loading, micelle morphology, size, respectively. The in vitro cytotoxic activity of DTX-micelles in HepG2, A549 and malignant melanoma B16 cells were evaluated by MTT assay. The corresponding in vivo antitumor efficacy was assessed in Kunming mice bearing B16 tumor after intravenous administration. The DTX-loading and efficiency into the micelles were 2.12 ± 0.09% and 86.34 ± 3.32%, respectively. The DTX-micelles were spherical with a mean particle size of 50.7 nm and size distribution from 22 to 84 nm, which suggested that they should be able to selectively accumulate in solid tumors by means of EPR effect, with a zeta potential of −12.45 ± 3.24 mV. The in vitro release behavior of DTX from DTX-micelles followed the Weibull equation. Compared with Duopafei®, DTX-micelles showed higher cytotoxicity against HepG2 (P < 0.01), A549 (P < 0.05) and B16 (P < 0.01) cells. In addition, DTX-micelles exhibited remarkable antitumor activity and reduced toxicity on B16 tumor in vivo. The tumor inhibition rates (TIR) of DTX-micelles was 91.6% versus 76.3% of Duopafei® (P < 0.01). These results suggested that P123 micelles might be considered as an effective DTX delivery system

    Neutrino Physics with JUNO

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    The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purposeunderground liquid scintillator detector, was proposed with the determinationof the neutrino mass hierarchy as a primary physics goal. It is also capable ofobserving neutrinos from terrestrial and extra-terrestrial sources, includingsupernova burst neutrinos, diffuse supernova neutrino background, geoneutrinos,atmospheric neutrinos, solar neutrinos, as well as exotic searches such asnucleon decays, dark matter, sterile neutrinos, etc. We present the physicsmotivations and the anticipated performance of the JUNO detector for variousproposed measurements. By detecting reactor antineutrinos from two power plantsat 53-km distance, JUNO will determine the neutrino mass hierarchy at a 3-4sigma significance with six years of running. The measurement of antineutrinospectrum will also lead to the precise determination of three out of the sixoscillation parameters to an accuracy of better than 1\%. Neutrino burst from atypical core-collapse supernova at 10 kpc would lead to ~5000inverse-beta-decay events and ~2000 all-flavor neutrino-proton elasticscattering events in JUNO. Detection of DSNB would provide valuable informationon the cosmic star-formation rate and the average core-collapsed neutrinoenergy spectrum. Geo-neutrinos can be detected in JUNO with a rate of ~400events per year, significantly improving the statistics of existing geoneutrinosamples. The JUNO detector is sensitive to several exotic searches, e.g. protondecay via the pK++νˉp\to K^++\bar\nu decay channel. The JUNO detector will providea unique facility to address many outstanding crucial questions in particle andastrophysics. It holds the great potential for further advancing our quest tounderstanding the fundamental properties of neutrinos, one of the buildingblocks of our Universe

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Epidemiology of Birth Defects Based on a Birth Defect Surveillance System from 2005 to 2014 in Hunan Province, China.

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    To describe the epidemiology of birth defects (BDs) in perinatal infants in Hunan Province, China, between 2005 and 2014.The BD surveillance data of perinatal infants (for stillbirth, dead fetus or live birth between 28 weeks of gestation and 7 days after birth) were collected from 52 registered hospitals of Hunan between 2005 and 2014. The prevalence rates of BDs with 95% confidence interval (CI) and crude odds ratio (ORs) were calculated to examine the associations of infant gender, maternal age, and region (urban vs rural) with BDs.From 2005 to 2014, there were a total of 925413 perinatal infants of which 17753 had BDs, with the average prevalence of 191.84 per 10000 PIs (perinatal infants), showing a significant uptrend. The risks of BDs are higher in urban areas versus rural areas (OR = 1.20), in male infants versus female infants (OR = 1.19), and in mothers above age 35 versus those below age 35 (OR = 1.24). The main five types of BDs are Congenital heart defects (CHD), Other malformation of external ear (OMEE), Polydactyly, Congenital malformation of kidney (CMK), and Congenital talipes equinovarus (CTE). From 2005 to 2014, the prevalence rates (per 10000 PIs) of CHD and CMK increased significantly from 22.56 to 74 (OR = 3.29, 95%CI: 2.65-4.11) and from 7.61 to 14.62 (OR = 1.92, 95%CI:1.30-2.84), respectively; the prevalence rates of congenital hydrocephalus and neural tube defects (NTDs) decreased significantly from 11.8 to 5.29 (OR = 0.45, 95%CI: 0.31-0.65) and from 7.87 to 1.74 (OR = 0.22, 95%CI: 0.13-0.38), respectively.The prevalence rates of specific BDs in perinatal infants in Hunan have changed in the last decade. Urban pregnant women, male perinatal infants, and mothers above age 35 present different prevalence rates of BDs. Wider use of new diagnosis technology, improving the ability of monitoring, strengthening the publicity and education are important to reduce the prevalence of BDs

    The Differences of Population Birth Defects in Epidemiology Analysis between the Rural and Urban Areas of Hunan Province in China, 2014–2018

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    Objectives. To compare the differences of epidemiology analysis in population birth defects (BDs) between the rural and urban areas of Hunan Province in China. Methods. The data of population-based BDs in Liuyang county (rural) and Shifeng district (urban) in Hunan Province for 2014–2018 were analyzed. BD prevalence rates, percentage change, and annual percentage change (APC) by sex and age were calculated to evaluate time trends. Risk factors associated with BDs were assessed using simple and multiple logistic regression analyses. Results. The BD prevalence rate per 10,000 perinatal infants (PIs) was 220.54 (95% CI: 211.26-230.13) in Liuyang and 181.14 (95% CI: 161.18-202.87) in Shifeng. Significant decreasing trends in BD prevalence rates were noted in the female PIs (APC=−9.31, P=0.044) and the total BD prevalence rate in Shifeng (APC=−14.14, P=0.039). Risk factors for BDs were as follows: rural area, male PIs, PIs with gestational age<37 weeks, PIs with birth weight<2500 g, and migrant pregnancies. Conclusions. We should focus on rural areas, reduce the prevalence of premature and low birth weight infants, and provide maternal healthcare services for migrant pregnancies for BD prevention from the perspective of population-based BD surveillance

    Ureterocele: Review of Presentations, Types, and Coexisting Diseases

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    Abstract Introduction: Ureterocele is swelling in one of the ureters that carry urine from the kidney to the bladder, which can block urine flow. An ureterocele usually occurs in the lower part of the ureter, where the ureter enters the bladder. Ureteroceles are equally common in both left- and right-side ureters. Some persons with ureteroceles are asymptomatic. Often, the diagnosis is made later in life due to kidney stones. Materials and methods: A systematic review was accomplished using Medline to obtain articles related to ureteroceles in English, Spanish, Italian, and French. Interests were focused on presentations, types and coexisting diseases for ureterocele. Results: Ureterocele can present with urinary tract infection, urinary retention, urinary incontinence, abdominal or loin pain, abdominal or vulvar mass, abdominal distention, hematuria, or vaginal bleeding. We can type the ureteroceles based on its location (ectopic or intravesicle), its association with triplicate system, duplication system, or single system, prenatal or postnatal, pediatric or adult, female or male, and thick or non-thick. The co-existing diseases include ureteral calculus, tumor, and congenital urinary tract abnormalities. Large ureteroceles are usually diagnosed earlier than smaller ones. An ureterocele may be discovered during a pregnancy ultrasound. Children with this condition often have severe urinary tract infections. Conclusions: The review suggests that there are various presentations, types and coexisting diseases for ureteroceles. Findings implicate the importance of considering these variables when making treatment decision in patients with ureteroceles
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