39 research outputs found
Seasonal behaviour of tidal damping and residual water level slope in the Yangtze River estuary: identifying the critical position and river discharge for maximum tidal damping
As a tide propagates into the estuary, river discharge affects tidal damping, primarily via a friction term,
attenuating tidal motion by increasing the quadratic velocity in the numerator, while reducing the effective friction
by increasing the water depth in the denominator. For the
first time, we demonstrate a third effect of river discharge
that may lead to the weakening of the channel convergence
(i.e. landward reduction of channel width and/or depth). In
this study, monthly averaged tidal water levels (2003–2014)
at six gauging stations along the Yangtze River estuary are
used to understand the seasonal behaviour of tidal damping and residual water level slope. Observations show that
there is a critical value of river discharge, beyond which
the tidal damping is reduced with increasing river discharge.
This phenomenon is clearly observed in the upstream part
of the Yangtze River estuary (between the Maanshan and
Wuhu reaches), which suggests an important cumulative effect of residual water level on tide–river dynamics. To understand the underlying mechanism, an analytical model has
been used to quantify the seasonal behaviour of tide–river
dynamics and the corresponding residual water level slope
under various external forcing conditions. It is shown that a
critical position along the estuary.info:eu-repo/semantics/publishedVersio
Template Attacks Based on the Multivariate Joint Distribution
For template attacks, it is ideal if templates can be built for each (data,key) pair. However, it requires a lot of power traces and computation. In this paper, firstly, the properties of the UMJD(unisource multivariate joint distribution) are studied, and then a template attack based on the UMJD is presented. For power traces with much noise, the experiments show that its attack effect is much better than that of the CPA(correlation power analysis) based template attacks and that of the SOST(sum of square wise pair t-differences) based template attacks. Secondly, the problem to build a template for each (data,key) pair can be reduced to build templates for an MMJD (multisource multivariate joint distribution). An MMJD can be divided into several UMJDs. Based on the analysis, we give a template attack that does not require large amounts of computations, and neither a large number of power traces for profiling, but with its attack effect equivalent to that of the template attack which aims to build a template for each (data,key) pair. Third, from the process of the UMJD based template attacks, using the POI (points of interest) of all variables together as the POI of the template attack is an extension to the existing conclusion on the optimal number of POI. Lastly, the UMJD can also be applied in the SOST method to obtain better quality of POI
Preparation and Membrane Permeability of Curcumin Nanoparticles by Subcritical Water Technology
Curcumin (Cur) nanoparticles were prepared by subcritical water (SBCW) method and its membrane permeability was evaluated. The processing conditions for the preparation of curcumin nanoparticles were investigated in terms of its particle size distribution, polydispersity index (PDI) and zeta potential, and the prepared nanoparticles were characterized and evaluated for in vitro membrane permeability. The results showed that nanoparticles with a diameter of 166 nm and a drug loading of 70.2% were obtained under the conditions: SBCW temperature 120 ℃, receiving solvent temperature 0 ℃, subcritical water/receiving solution ratio 1:3 (V/V), 0.04 g/100 mL lactose as stabilizing agent, and 30% (V/V) ethanol as entrainer. Fourier transform infrared (FTIR) spectroscopy showed no structural changes in Cur. Scanning electron microscopy (SEM) showed that Cur nanoparticles were uniformly spherical in shape. Differential scanning calorimetry (DSC) analysis showed a decrease in the crystallinity of the nanoparticles. Cur nanoparticles exhibited excellent membrane permeability in vitro, and the permeation rate in the first two hours was 25 folds higher than that of free Cur. Furthermore, Cur nanoparticles exhibited good transmembrane capacity in rabbits and significantly enhanced the bioavailability of Cur. The preparation of Cur nanoparticles using subcritical water method has the advantages of high drug loading, good membrane permeability, no need for carriers, simple process, and green environmental protection
Leucine Deprivation Increases Hepatic Insulin Sensitivity via GCN2/mTOR/S6K1 and AMPK Pathways
Polycomb group proteins EZH2 and EED directly regulate androgen receptor in advanced prostate cancer
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149265/1/ijc32118.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149265/2/ijc32118_am.pd
Selective Catalytic Dehydrogenative Oxidation of Bio-Polyols to Lactic Acid
The global demand for lactic acid (LA) is increasing due to its successful application as monomer for the manufacture of bioplastics. Although N-heterocyclic carbene (NHC) iridium complexes are promising molecular catalysts for LA synthesis, their instabilities have hindered their utilization especially in commercial applications. Here, we report that a porous self-supported NHC-iridium coordination polymer can efficiently prevent the clusterization of corresponding NHC-Ir molecules and can function as a solid molecular recyclable catalyst for dehydrogenation of bio-polyols to form LA with excellent activity (97 %) and selectivity (>99 %). A turnover number of up to 5700 could be achieved in a single batch, due to the synergistic participation of the Ba2+ and hydroxide ions, as well as the blockage of unwanted pathways by adding methanol. Our findings demonstrate a potential route for the industrial production of LA from cheap and abundant bio-polyols, including sorbitol
A novel DNA sequence periodicity decodes nucleosome positioning
There have been two types of well-characterized DNA sequence periodicities; both are found to be associated with important molecular mechanisms. One is a 3-nt periodicity corresponding to codon triplets, the other is a 10.5-nt periodicity related to the structure of DNA helixes. In the process of analyzing the genome and transcriptome of Trichomonas vaginalis, we observed a 120.9-nt periodicity along DNA sequences. Different from the 3- and 10.5-nt periodicities, this novel periodicity originates near the 5′-end of transcripts, extends along the direction of transcription, and weakens gradually along transcripts. As a result, codon usage as well as amino acid composition is constrained by this periodicity. Similar periodicities were also identified in other organisms, but with variable length associated with the length of nucleosome units. We validated this association experimentally in T. vaginalis, and demonstrated that the periodicity manifests nucleotide variations between linker-DNA and wrapping-DNA along nucleosome array. We conclude that this novel DNA sequence periodicity is a signature of nucleosome organization suggesting that nucleosomes are well-positioned with regularity, especially near the 5′-end of transcripts
A Journey into the City. Migrant Workers' Relation with the Urban Space and Struggle for Existence in Xu Zechen's Early Jingpiao Fiction
In contemporary China, rural-urban migrants constitute a new urban subject with entirely new identity-related issues. This study aims at demonstrating how literature can be a valid field in investigating such evolving subjectivities, through an analysis of Xu Zechen’s early novellas depicting migrants’ vicissitudes in Beijing. Combining a close reading of the texts and a review of the main social problems characterising rural-urban migration in China, this paper focuses on the representation of the identity crisis within the migrant self in Xu’s stories, taking into account the network of meanings employed by the writer to signify the objective and subjective tension between the city and the countryside
An automatic segmentation method for heart sounds
Abstract Background There are two major challenges in automated heart sound analysis: segmentation and classification. An efficient segmentation is capable of providing valuable diagnostic information of patients. In addition, it is crucial for some feature-extraction based classification methods. Therefore, the segmentation of heart sound is of significant value. Methods This paper presents an automatic heart sound segmentation method that combines the time-domain analysis, frequency-domain analysis and time–frequency-domain analysis. Employing this method, the boundaries of heart sound components are first located, and the components are then recognized. Finally, the heart sounds are divided into several segments on the basis of the results of boundary localization and component identification. Results In order to evaluate the performance of the proposed method, quantitative experiments are performed on an authoritative heart sound database. The experimental results show that the boundary localization has a sensitivity (Se) of 100%, a positive predictive value (PPV) of 99.3% and an accuracy (Acc) of 99.93%. Moreover, the Se, PPV and Acc of component identification reach 98.63, 99.86 and 98.49%, respectively. Conclusion The proposed method shows reliable performance on the segmentation of heart sounds. Compared with previous works, this method can be applied to not only normal heart sounds, but also the sounds with S3, S4 and murmurs, thus greatly increasing the applied range
Stabilizing undulated lamellae by diblock copolymers confined in alternately adsorbed thin films
The self-assembly behavior of AB diblock copolymer confined in staggering alternately adsorbed thin films is studied using the self-consistent field theory (SCFT) and dissipative particle dynamics (DPD), focusing on the emergence and stability of the undulated lamella (UL) phase. Phase diagrams for the volume fraction of blocks, period of the adsorbed pattern and thickness of the confinement are constructed. Our results indicate that the UL phase can be stable in the case with a large period of adsorbed pattern, and is more favorable in the asymmetrical diblock copolymer with volume fraction around f = 0.40, which becomes cylindrical phases (C) with too small f and transforms into tilted lamellae (TL) on the contrary. Furthermore, the number of layers in the UL phases can be regulated by adjusting the period of the adsorbed pattern and the confinement degree of the thin film. In addition, the formation of the UL is verified by DPD simulations. The study demonstrates that the specially confined diblock copolymers provide an efficient route to regulate the stability of the complex UL phases