3,332 research outputs found
Phenylboronic acid-diol crosslinked 6-<i>O</i>-vinylazeloyl-d-galactose nanocarriers for insulin delivery
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
Super-Reflection in Fluid Discs: Corotation Amplifier, Corotation Resonance, Rossby Waves, and Overstable Modes
In differentially rotating discs with no self-gravity, density waves cannot
propagate around the corotation, where the wave pattern rotation speed equals
the fluid rotation rate. Waves incident upon the corotation barrier may be
super-reflected (commonly referred to as corotation amplifier), but the
reflection can be strongly affected by wave absorptions at the corotation
resonance/singularity. The sign of the absorption is related to the Rossby wave
zone very near the corotation radius. We derive the explicit expressions for
the complex reflection and transmission coefficients, taking into account wave
absorption at the corotation resonance. We show that for generic discs, this
absorption plays a much more important role than wave transmission across the
corotation barrier. Depending on the sign of the gradient of the specific
vorticity of the disc the corotation resonance can either enhance or diminish
the super-reflectivity, and this can be understood in terms of the location of
the Rossby wave zone relative to the corotation radius. Our results provide the
explicit conditions (in terms of disc thickness, rotation profile and specific
vorticity gradient) for which super-reflection can be achieved. Global
overstable disc modes may be possible for discs with super-reflection at the
corotation barrier.Comment: 16 pages, 5 figures, MNRAS in pres
Gene targeting for O -methyltransferase genes, mycE and mycF , on the chromosome of Micromonospora griseorubida producing mycinamicin with a disruption cassette containing the bacteriophage φC31 attB attachment site
Mycinamicin, a 16-membered macrolide antibiotic produced by Micromonospora griseorubida , comprises a macrolactone and two deoxysugars: desosamine and mycinose. Mycinose is synthesized through two modification steps: the methylation of 6-deoxyallose in mycinamicin VI and of javose in mycinamicin III. To confirm the role of mycE and mycF genes in mycinamicin biosynthesis in M. griseorubida , disruption mutants of mycE and mycF were constructed by disruption plasmids containing attB in the disruption cassette FRT -neo-oriT- FRT -attB for the integration of φC31-derivative vector plasmids; the disruption mutants were complemented through the integration of pSET152 derivatives containing intact mycE or mycF into the artificially inserted attB site. These disruption mutants did not produce mycinamicin II, but mainly accumulated mycinamicins VI and III, indicating that MycE and MycF methylated the C2″-OH group of 6-deoxyallose in mycinamicin VI and the C3″-OH group of C2″-methylated 6-deoxyallose in mycinamicin III, respectively. The complemented strains of mycE and mycF recovered the mycinamicin II productivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79258/1/j.1574-6968.2010.01899.x.pd
Anomaly Detection in Social Media Using Recurrent Neural Network
© 2019, Springer Nature Switzerland AG. In today’s information environment there is an increasing reliance on online and social media in the acquisition, dissemination and consumption of news. Specifically, the utilization of social media platforms such as Facebook and Twitter has increased as a cutting edge medium for breaking news. On the other hand, the low cost, easy access and rapid propagation of news through social media makes the platform more sensitive to fake and anomalous reporting. The propagation of fake and anomalous news is not some benign exercise. The extensive spread of fake news has the potential to do serious and real damage to individuals and society. As a result, the detection of fake news in social media has become a vibrant and important field of research. In this paper, a novel application of machine learning approaches to the detection and classification of fake and anomalous data are considered. An initial clustering step with the K-Nearest Neighbor (KNN) algorithm is proposed before training the result with a Recurrent Neural Network (RNN). The results of a preliminary application of the KNN phase before the RNN phase produces a quantitative and measureable improvement in the detection of outliers, and as such is more effective in detecting anomalies or outliers against the test dataset of 2016 US Presidential Election predictions
Working memory dysfunctions predict social problem solving skills in schizophrenia
The current study aimed to examine the contribution of neurocognition and social cognition to components of social problem solving. Sixty-seven inpatients with schizophrenia and 31 healthy controls were administrated batteries of neurocognitive tests, emotion perception tests, and the Chinese Assessment of Interpersonal Problem Solving Skills (CAIPSS). MANOVAs were conducted to investigate the domains in which patients with schizophrenia showed impairments. Correlations were used to determine which impaired domains were associated with social problem solving, and multiple regression analyses were conducted to compare the relative contribution of neurocognitive and social cognitive functioning to components of social problem solving. Compared with healthy controls, patients with schizophrenia performed significantly worse in sustained attention, working memory, negative emotion, intention identification and all components of the CAIPSS. Specifically, sustained attention, working memory and negative emotion identification were found to correlate with social problem solving and 1-back accuracy significantly predicted the poor performance in social problem solving. Among the dysfunctions in schizophrenia, working memory contributed most to deficits in social problem solving in patients with schizophrenia. This finding provides support for targeting working memory in the development of future social problem solving rehabilitation interventions. (C) 2014 Elsevier Ireland Ltd. All rights reserved
Residual stress distribution in a Ti-6Al-4V T-joint weld measured using synchrotron X-ray diffraction
To improve the manufacturing quality of welded structures, to prevent failures at weld joints and to predict their lifetime, measurements of the residual stresses generated by welding in the structures are extremely useful. The residual stresses may reduce the component life due to phenomena that occur at low applied stresses such as brittle fracture, fatigue and stress corrosion cracking. Welded thin Ti-6Al-4V panel components are commonly found in aero-engine assemblies and the weld integrity and reliability are critical. In this work, the residual stress distributions in a welded thin Ti-6Al-4V T-joint were measured by the newly developed SScanSS program with synchrotron X-ray diffraction technique. The measurement performed in this study, which included a large number of measurement points, has mapped a complete stress field in a thin sheet T-joint weld. It has not only provided improved understanding of residual stress in such a joint but also filled the missing link between the residual stress obtained by numerical modelling and their validation. The results have shown that the longitudinal stresses play the most important role in the residual stress distribution over the flange and high tensile stresses appear in the region near the weld zone. The measured results were compared with numerically predicted results and these showed good agreement
Antimicrobial effects of free nitrous acid on Desulfovibrio vulgaris: Implications for sulfide-induced corrosion of concrete
Hydrogen sulfide produced by sulfate reducing bacteria (SRB) in sewers causes odor problems and asset deterioration due to the sulfide induced concrete corrosion. Free nitrous acid (FNA) was recently demonstrated as a promising antimicrobial agent to alleviate hydrogen sulfide production in sewers. However, knowledge of the antimicrobial mechanisms of FNA is largely unknown. Here we report the multiple-targeted antimicrobial effects of FNA on the SRB Desulfovibrio vulgaris Hildenborough by determining growth, physiological and gene expression responses to FNA exposure. The activities of growth, respiration and ATP generation were inhibited when exposed to FNA. These changes were reflected in transcript levels detected during exposure. Removal of FNA was evident by nitrite reduction that likely involved nitrite reductase and the poorly characterised hybrid cluster protein, and the genes coding for these proteins were highly expressed. During FNA exposure lowered ribosome activity and protein production were detected. Additionally, conditions within the cells were more oxidising and there was evidence of oxidative stress. Based on interpretation of the measured responses we present a model depicting the antimicrobial effects of FNA on D. vulgaris. These findings provide new insight for understanding the responses of D. vulgaris to FNA and will provide foundation for optimal application of this antimicrobial agent for improved control of sewer corrosion and odor management
Tailoring hierarchical microstructures and nanoprecipitates in additive-manufactured Al-Zn-Mg-Cu-Nb alloys for simultaneously enhancing strength and ductility
Additive manufacturing provides an efficient way of producing metallic components with complex geometries. Their microstructure is substantially different to those from conventional processing, creating opportunities for manipulating the final microstructure and properties via heat treatment. Here, we demonstrate that as-built heterostructures in an Al-Zn-Mg-Cu-Nb alloy produced during the solidification of molten pools provide a driving force and additional Zener pinning sources for recrystallization. This creates a bimodal grain structure after solution treatment, causing additional hetero-deformation-induced strengthening and hardening. Coarse grains are found to promote work hardening and blunt the propagate of cracks during deformation, increasing ductility. Together with precipitation strengthening from a high number density nanoprecipitates, the simultaneous improvement of strength and ductility in a highly alloyed Al-Zn-Mg-Cu-Nb alloy is achieved. These results provide a simple strategy for the development of additively manufactured age-hardening alloys with improved strength and ductility for high performance structural applications
Co- evolving wing spots and mating displays are genetically separable traits in Drosophila
The evolution of sexual traits often involves correlated changes in morphology and behavior. For example, in Drosophila, divergent mating displays are often accompanied by divergent pigment patterns. To better understand how such traits co- evolve, we investigated the genetic basis of correlated divergence in wing pigmentation and mating display between the sibling species Drosophila elegans and Drosophila gunungcola. Drosophila elegans males have an area of black pigment on their wings known as a wing spot and appear to display this spot to females by extending their wings laterally during courtship. By contrast, D. gunungcola lost both of these traits. Using Multiplexed Shotgun Genotyping (MSG), we identified a - ¼440 kb region on the X chromosome that behaves like a genetic switch controlling the presence or absence of male- specific wing spots. This region includes the candidate gene optomotor- blind (omb), which plays a critical role in patterning the Drosophila wing. The genetic basis of divergent wing display is more complex, with at least two loci on the X chromosome and two loci on autosomes contributing to its evolution. Introgressing the X- linked region affecting wing spot development from D. gunungcola into D. elegans reduced pigmentation in the wing spots but did not affect the wing display, indicating that these are genetically separable traits. Consistent with this observation, broader sampling of wild D. gunungcola populations confirmed that the wing spot and wing display are evolving independently: some D. gunungcola males performed wing displays similar to D. elegans despite lacking wing spots. These data suggest that correlated selection pressures rather than physical linkage or pleiotropy are responsible for the coevolution of these morphological and behavioral traits. They also suggest that the change in morphology evolved prior to the change in behavior.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155953/1/evolution2019submissionsupplementaryfigurescompiledcompressed.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155953/2/evo13990_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155953/3/evo13990.pd
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