774 research outputs found
Stability of planar shock wave for the 3-dimensional compressible Navier-Stokes-Poisson equations
This paper is concerned with the stability of planar viscous shock wave for
the 3-dimensional compressible Navier-Stokes-Poisson (NSP) system in the domain
with
. The stability problem of viscous
shock under small 1-dimensional perturbations was solved in Duan-Liu-Zhang [7].
In this paper, we prove the viscous shock is still stable under small 3-d
perturbations. Firstly, we decompose the perturbation into the zero mode and
non-zero mode. Then we can show that both the perturbation and zero-mode
time-asymptotically tend to zero by the anti-derivative technique and crucial
estimates on the zero-mode. Moreover, we can further prove that the non-zero
mode tends to zero with exponential decay rate. The key point is to estimate
the non-zero mode of nonlinear terms involving electronic potential, see Lemma
6.1 below
Validation and Application of SMAP SSS Observation in Chinese Coastal Seas
Using sea surface salinity (SSS) from the Soil Moisture Active Passive (SMAP) mission from September 2015 to August 2016, the spatial distribution and seasonal variation in SSS in the Chinese coastal seas were investigated. First, in situ salinity observation over Chinese East Sea was used to validate SMAP observation. Then, the SSS signature of the Yangtze River fresh water was analyzed using SMAP data and the river discharge data. The SSS around the Yangtze River estuary in the Chinese East Sea, the Bohai Sea and the Yellow Sea is significantly lower than that of the open ocean. The SSS of Chinese coastal seas shows significant seasonal variation, and the seasonal variation in the adjacent waters of the Yangtze River estuary is the most obvious, followed by that of the Pearl River estuary. The minimum value of SSS appears in summer while maximum in winter. The root-mean-squared difference of daily SSS between SMAP observation and in situ observation is around 3 psu in both summer and winter, which is much lower than the annual range of SSS variation. The path of fresh water from SMAP and in situ observation is consistent during summer time
Boosting Fast Adversarial Training with Learnable Adversarial Initialization
Adversarial training (AT) has been demonstrated to be effective in improving
model robustness by leveraging adversarial examples for training. However, most
AT methods are in face of expensive time and computational cost for calculating
gradients at multiple steps in generating adversarial examples. To boost
training efficiency, fast gradient sign method (FGSM) is adopted in fast AT
methods by calculating gradient only once. Unfortunately, the robustness is far
from satisfactory. One reason may arise from the initialization fashion.
Existing fast AT generally uses a random sample-agnostic initialization, which
facilitates the efficiency yet hinders a further robustness improvement. Up to
now, the initialization in fast AT is still not extensively explored. In this
paper, we boost fast AT with a sample-dependent adversarial initialization,
i.e., an output from a generative network conditioned on a benign image and its
gradient information from the target network. As the generative network and the
target network are optimized jointly in the training phase, the former can
adaptively generate an effective initialization with respect to the latter,
which motivates gradually improved robustness. Experimental evaluations on four
benchmark databases demonstrate the superiority of our proposed method over
state-of-the-art fast AT methods, as well as comparable robustness to advanced
multi-step AT methods. The code is released at
https://github.com//jiaxiaojunQAQ//FGSM-SDI.Comment: Accepted by TI
Interference of steroidogenesis by gold nanorod core/silver shell nanostructures: Implications for reproductive toxicity of silver nanomaterials
Silver nanomaterials are widely used in personal care products. Recent studies have indicated that these nanomaterials may penetrate the blood-placental barrier and gain access to the ovaries. It is largely unknown how silver nanomaterials influence ovarian physiology and functions such as hormone production. This study examines the in vitro toxicology of silver nanomaterials, focusing especially on cytotoxicity and steroidogenesis while exploring their underlying mechanisms. In this study, primary rat granulosa cells were exposed to gold nanorod core/silver shell nanostructures (Au@Ag NRs), which were compared to cells exposed to gold nanorods only. The Au@Ag NRs generated more reactive oxygen species (ROS), reduced mitochondrial membrane potential, and decreased production of adenosine triphosphate. Au@Ag NRs promoted steroidogenesis, including progesterone and estradiol, in a time and dose-dependent manner. Chemical reactivity and transformation of Au@Ag NRs were then studied by electron spin resonance spectroscopy (ESR) and X-ray absorption near edge structure, which identified the generation of free radicals and intracellular silver species. These results suggested that both particle-specific activity and intracellular silver ion release of Au@Ag
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CHFR is important for the first wave of ubiquitination at DNA damage sites
Protein ubiquitination plays an important role in activating the DNA damage response and maintain-ing genomic stability. In response to DNA double-strand breaks (DSBs), a ubiquitination cascade occurs at DNA lesions. Here, we show that checkpoint with Forkhead-associated (FHA) and RING finger domain protein (CHFR), an E3 ubi-quitin ligase, is recruited to DSBs by poly(ADP-ribose) (PAR). At DSBs, CHFR regulates the first wave of protein ubiquitination. Moreover, CHFR ubiquitinates PAR polymerase 1 (PARP1) and regulates chromatin-associated PARP1 in vivo. Thus, these results demonstrate that CHFR is an important E3 ligase in the early stage of the DNA damage response, which mediates the crosstalk between ubiquitination and poly-ADP-ribosylation
Potential molecular targets for intervention in pelvic organ prolapse
Pelvic organ prolapse (POP) is a concerning gynecological benign illness in middle-aged and senior women. Its etiology is complex, the incidence rate is high, symptoms are clinically subjective, and its influence tends to be polarized. At present, for those who need medical treatment, whether surgical or non-surgical, complications cannot be ignored, and treatment effect needs to be optimized. However, there is a lack of accurate molecular biological interventions for the prevention, diagnosis, progression delay, and treatment of POP. Here, we reviewed the current state of understanding of the molecular mechanisms and factors associated with POP etiology. These factors include cyclins, matrix metal peptidases/tissue inhibitors of metalloproteinases, microRNAs, homeobox A11, transforming growth factor β1, insulin-like growth factor 1, fibulin 5, lysyl oxidase-like 1, oxidative stress, inflammatory response, estrogen, and other potential biomarkers associated with POP. In addition, relevant molecular targets that may be used to intervene in POP are summarized. The aim of this review was to provide more information to identify accurate potential biomarkers and/or molecular targets for the prevention, diagnosis, progression delay, and treatment of POP, with the goal of improving medical treatment for patients at-risk for POP or having POP. Continued research is needed to identify additional details of currently accepted molecular mechanisms and to identify additional mechanisms that contribute to POP
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