5,219 research outputs found

    Phenylboronic acid-diol crosslinked 6-<i>O</i>-vinylazeloyl-d-galactose nanocarriers for insulin delivery

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    A new block polymer named poly 3-acrylamidophenylboronic acid-b-6-O–vinylazeloyl-d-galactose (p(AAPBA-b-OVZG)) was prepared using 3-acrylamidophenylboronic acid (AAPBA) and 6-O-vinylazeloyl-D-galactose (OVZG) via a two-step procedure involving S-1-dodecyl-S-(α', α'-dimethyl-α″-acetic acid) trithiocarbonate (DDATC) as chain transfer agent, 2,2-azobisisobutyronitrile (AIBN) as initiator and dimethyl formamide (DMF) as solvent. The structures of the polymer were examined by Fourier transform infrared spectroscopy (FT-IR) and 1H NMR and the thermal stability was determined by thermal gravimetric analysis (TG/DTG). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were utilized to evaluate the morphology and properties of the p(AAPBA-b-OVZG) nanoparticles. The cell toxicity, animal toxicity and therapeutic efficacy were also investigated. The results indicate the p(AAPBA-b-OVZG) was successfully synthesized and had excellent thermal stability. Moreover, the p(AAPBA-b-OVZG) nanoparticles were submicron in size and glucose-sensitive in phosphate-buffered saline (PBS). In addition, insulin as a model drug had a high encapsulation efficiency and loading capacity and the release of insulin was increased at higher glucose levels. Furthermore, the nanoparticles showed a low-toxicity in cell and animal studies and they were effective at decreasing blood glucose levels of mice over 96 h. These p(AAPBA-b-OVZG) nanoparticles show promise for applications in diabetes treatment using insulin or other hypoglycemic proteins

    A Practical Guide for X-Ray Diffraction Characterization of Ga(Al, In)N Alloys

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    Ga(In, Al)N alloys are used as an active layer or cladding layer in light emitting diodes and laser diodes. x-ray diffraction is extensively used to evaluate the crystalline quality, the chemical composition and the residual strain in Ga(Al,In)N thin films, which directly determine the emission wavelength and the device performance. Due to the minor mismatch in lattice parameters between Ga(Al, In)N alloy and a GaN virtual substrate, x-ray diffraction comes to a problem to separate the signal from Ga(Al,In)N alloy and GaN. We give a detailed comparison on different diffraction planes. In order to balance the intensity and peak separation between Ga(Al,In)N alloy and GaN, (0004) and (1015) planes make the best choice for symmetric scan and asymmetric scan, respectively.Comment: 9 pages, 5 figure

    The Effect of Cluster Position Determined by Vineyard Row Orientation on Grape Flavonoids and Aroma Profiles of Vitis vinifera L. cv. Cabernet Sauvignon and Italian Riesling in the North Foot of Tianshan Mountains

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    Vineyard row orientation plays a critical role in determining cluster microclimate. This study aimed tofigure out how cluster positions determined by vineyard row orientation affect grape flavonoids and aromaprofiles of Cabernet Sauvignon and Italian Riesling grapes. Three cluster positions (two canopy sidesand the inner canopy) of NS and EW oriented row Cabernet Sauvignon and NS oriented row ItalianRiesling were selected for the experiment. Microclimate data was monitored around clusters from bothcanopy sides of different row orientations. The south canopy side had higher daytime temperaturesand PAR than the north canopy side in EW row orientation. Flavonoids of grape skins and seeds wereseparated and determined by LC-MS, and aroma compounds of grape must were determined by GC-MS.Results showed that flavanols were affected by orientations, and EW orientation had higher berries skinflavanol concentration than NS orientation. EW-IN berries had fewer glucuronide form flavonols and3’-hydroxylated flavonols than the other two positions in EW orientation. Inner canopy berries had lowerflavonol concentration than other positions in EW orientation of CS and NS orientation of IR. To aromas,C6/C9 were the main compounds significantly affected by row orientations. EW orientation berries hadhigher C6 alcohols concentration such as (E)-3-Hexen-1-ol, (E)-2-Hexen-1-ol and (Z)-3-Hexen-1-ol thanNS orientation, while NS orientation berries had higher C6 aldehyde concentrations such as Hexanal and(E)-2-hexenal than EW orientation. EW-IN berries had more abundant C6/C9 compounds than the othertwo positions. The study provided preliminary scientific evidence for vineyard viticulture practice andharvest strategy

    Effects of crystallinity and point defects on optoelectronic applications of β-Ga2O3 epilayers

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    This study evaluates the effect of crystallinity and point defects on time-dependent photoresponsivity and the cathodoluminescence (CL) properties of β-Ga2O3 epilayers. A synchrotron high-resolution X-ray technique was used to understand the crystalline structure of samples. Rutherford backscattering spectroscopy was used to determine the net chemical composition of the samples to examine the type and ratio of their possible point defects. The results show that in functional time-dependent photoresponsivity of photodetectors based on β-Ga2O3 epilayers, point defects contribution overcomes the contribution of crystallinity. However, the crystalline structure affects the intensities and emission regions of CL spectra more than point defects

    Molecular Line Profiles of Collapsing Gas Clouds

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    Emission line profiles of tracer molecule H2_2CO 140 GHz transition from gravitational core collapsing clouds in the dynamic process of forming protostars are calculated, using a simple ray-tracing radiative transfer model. Three self-similar dynamic inside-out core collapse models -- the conventional polytropic model, the empirical hybrid model and the isothermal model -- for star-forming molecular clouds are examined and compared. The isothermal model cannot produce observed asymmetric double-peak molecular line profiles. The conventional polytropic model, which gives flow velocity, mass density and temperature profiles self-consistently, can produce asymmetric double-peak line profiles for a core collapsing cloud. In particular, the blue peak is stronger than the red peak, consistent with a broad class of molecular line profile observations. The relative strengths of the blue and red peaks within a molecular line profile are determined by the cloud temperature gradient. The conventional polytropic model can be utilized to produce molecular line-profile templates, for extracting dynamical information from line spectra of molecular globules undergoing a gravitational core collapse. We show a sample fit using the 140 GHz H2_2CO emission line from the central region of the molecular globule B335 by our model with γ=1.2\gamma=1.2. The calculation of line profiles and fitting processes also offer a scenario to estimate the protostellar mass, the kernel mass accretion rate, and the evolution time scale of a core collapsing cloud. Our model can be readily adapted to other tracer molecules with more or less constant abundances in star-forming clouds.Comment: 12 pages, 10 figures, accepted for publication in MNRA

    Methanol maser associated outflows: detection statistics and properties

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    We have selected the positions of 54 6.7 GHz methanol masers from the Methanol Multibeam Survey catalogue, covering a range of longitudes between 20° and 34° of the Galactic plane. These positions were mapped in the J = 3-2 transition of both the 13CO and C18O lines. A total of 58 13CO emission peaks are found in the vicinity of these maser positions. We search for outflows around all 13CO peaks, and find evidence for high-velocity gas in all cases, spatially resolving the red and blue outflow lobes in 55 cases. Of these sources, 44 have resolved kinematic distances, and are closely associated with the 6.7 GHz masers, a subset referred to as Methanol Maser Associated Outflows (MMAOs). We calculate the masses of the clumps associated with each peak using 870 mum continuum emission from the ATLASGAL survey. A strong correlation is seen between the clump mass and both outflow mass and mechanical force, lending support to models in which accretion is strongly linked to outflow. We find that the scaling law between outflow activity and clump masses observed for low-mass objects, is also followed by the MMAOs in this study, indicating a commonality in the formation processes of low-mass and high-mass stars

    Prenatal exposure to TAK242 affects the childhood autism in offspring in animal models of autism spectrum disorder

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    Objective(s): To evaluate whether prenatal exposure to TAK242 affects childhood autism in the offspring in animal models of autism spectrum disorder (ASD). Materials and Methods:The pregnant rats were pseudo-randomly divided into three groups, the ASD model group, the TAK242 treatment group, and the control group. The ASD model was constructed by injecting IP with LPS. The blood samples from 1-month-old offspring were collected for cytokine evaluation and the social interaction test was used in the offspring of ASD rats. Rats were killed and the hippocampus, cerebral cortex, and cerebellum were used for the immunohistochemical study. Results: As compared to the control, the levels of IFN-γ, IL-1β, IL-2, and IL-6 were significantly increased (

    Chandra observations and classification of AGN-candidates correlated with Auger UHECRs

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    We report on Chandra X-ray observations of possible-AGNs which have been correlated with Ultra-high Energy Cosmic Rays (UHECRs) observed by the Pierre Auger Collaboration. Combining our X-ray observations with optical observations, we conclude that one-third of the 21 Veron-Cetty Veron (VCV) galaxies correlating with UHECRs in the first Auger data-release are actually not AGNs. We review existing optical observations of the 20 VCV galaxies correlating with UHECRs in the second Auger data-release and determine that three of them are not AGNs and two are uncertain. Overall, of the 57 published UHECRs with |b|>10 degrees, 22 or 23 correlate with true AGNs using the Auger correlation parameters. We also measured the X-ray luminosity of ESO139-G12 to complete the determination of the bolometric luminosities of AGNs correlating with UHECRs in the first data-set. Apart from two candidate sources which require further observation, we determined bolometric luminosities for the candidate galaxies of the second dataset. We find that only two of the total of 69 published UHECRs correlate with AGNs (IC5135 and IC4329a) which are powerful enough in their steady-state to accelerate protons to the observed energies of their correlated UHECRs. The GZK expectation is that about 45% of the sources of UHECRs above 60 EeV should be contained within the z<0.018 volume defined by the Auger scan analysis, so an observed level of 30-50% correlation with weak AGNs is compatible with the suggestion that AGNs experience transient high-luminosity states during which they accelerate UHECRs.Comment: ApJ in press; extends and supersedes arXiv:1109.0267. arXiv admin note: substantial text overlap with arXiv:1109.026
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