190 research outputs found
Growth of Thin Oxidation-Resistive Crystalline Si Nanostructures on Graphene
We report the growth of Si nanostructures, either as thin films or
nanoparticles, on graphene substrates. The Si nanostructures are shown to be
single crystalline, air stable and oxidation resistive, as indicated by the
observation of a single crystalline Si Raman mode at around 520 cm-1, a STM
image of an ordered surface structure under ambient condition, and a Schottky
junction with graphite. Ultra-thin silicon regions exhibit silicene-like
behavior, including a Raman mode at around 550 cm-1, a triangular lattice
structure in STM that has distinctly different lattice spacing from that of
either graphene or thicker Si, and metallic conductivity of up to 500 times
higher than that of graphite. This work suggests a bottom-up approach to
forming a Si nanostructure array on a large scale patterned graphene substrate
for fabricating nanoscale Si electronic devices
Semi-WTC: A Practical Semi-supervised Framework for Attack Categorization through Weight-Task Consistency
Supervised learning has been widely used for attack categorization, requiring
high-quality data and labels. However, the data is often imbalanced and it is
difficult to obtain sufficient annotations. Moreover, supervised models are
subject to real-world deployment issues, such as defending against unseen
artificial attacks. To tackle the challenges, we propose a semi-supervised
fine-grained attack categorization framework consisting of an encoder and a
two-branch structure and this framework can be generalized to different
supervised models. The multilayer perceptron with residual connection is used
as the encoder to extract features and reduce the complexity. The Recurrent
Prototype Module (RPM) is proposed to train the encoder effectively in a
semi-supervised manner. To alleviate the data imbalance problem, we introduce
the Weight-Task Consistency (WTC) into the iterative process of RPM by
assigning larger weights to classes with fewer samples in the loss function. In
addition, to cope with new attacks in real-world deployment, we propose an
Active Adaption Resampling (AAR) method, which can better discover the
distribution of unseen sample data and adapt the parameters of encoder.
Experimental results show that our model outperforms the state-of-the-art
semi-supervised attack detection methods with a 3% improvement in
classification accuracy and a 90% reduction in training time.Comment: Tech repor
Differential Cryptanalysis of SMS4 Block Cipher
SMS4 is a 128-bit block cipher used in the
WAPI standard for wireless networks in China. In this paper, we
analyze the security of SMS4 block cipher against differential
cryptanalysis. Firstly, we prove three theorems and one corollary
that reflect relationships of 5- and 6-round SMS4. Nextly, by
these relationships, we clarify the minimum number of differentially
active S-boxes in 6-, 7- and 12-round SMS4 respectively.
Finally, based on the above results, we present a family of about
differential characteristics for 19-round SMS4, which
leads to an attack on 23-round SMS4 with chosen
plaintexts and encryptions. Our attack is the best known
attack on SMS4 so far
Identification of copper death-associated molecular clusters and immunological profiles in rheumatoid arthritis
Objective: An analysis of the relationship between rheumatoid arthritis (RA) and copper death-related genes (CRG) was explored based on the GEO dataset. / Methods: Based on the differential gene expression profiles in the GSE93272 dataset, their relationship to CRG and immune signature were analysed. Using 232 RA samples, molecular clusters with CRG were delineated and analysed for expression and immune infiltration. Genes specific to the CRGcluster were identified by the WGCNA algorithm. Four machine learning models were then built and validated after selecting the optimal model to obtain the significant predicted genes, and validated by constructing RA rat models. / Results: The location of the 13 CRGs on the chromosome was determined and, except for GCSH. LIPT1, FDX1, DLD, DBT, LIAS and ATP7A were expressed at significantly higher levels in RA samples than in non-RA, and DLST was significantly lower. RA samples were significantly expressed in immune cells such as B cells memory and differentially expressed genes such as LIPT1 were also strongly associated with the presence of immune infiltration. Two copper death-related molecular clusters were identified in RA samples. A higher level of immune infiltration and expression of CRGcluster C2 was found in the RA population. There were 314 crossover genes between the 2 molecular clusters, which were further divided into two molecular clusters. A significant difference in immune infiltration and expression levels was found between the two. Based on the five genes obtained from the RF model (AUC = 0.843), the Nomogram model, calibration curve and DCA also demonstrated their accuracy in predicting RA subtypes. The expression levels of the five genes were significantly higher in RA samples than in non-RA, and the ROC curves demonstrated their better predictive effect. Identification of predictive genes by RA animal model experiments was also confirmed. / Conclusion: This study provides some insight into the correlation between rheumatoid arthritis and copper mortality, as well as a predictive model that is expected to support the development of targeted treatment options in the future
Mechanisms of increased risk of tumorigenesis in Atm and Brca1 double heterozygosity
<p>Abstract</p> <p>Background</p> <p>Both epidemiological and experimental studies suggest that heterozygosity for a single gene is linked with tumorigenesis and heterozygosity for two genes increases the risk of tumor incidence. Our previous work has demonstrated that <it>Atm/Brca1 </it>double heterozygosity leads to higher cell transformation rate than single heterozygosity. However, the underlying mechanisms have not been fully understood yet. In the present study, a series of pathways were investigated to clarify the possible mechanisms of increased risk of tumorigenesis in <it>Atm </it>and <it>Brca1 </it>heterozygosity.</p> <p>Methods</p> <p>Wild type cells, <it>Atm </it>or <it>Brca1 </it>single heterozygous cells, and <it>Atm</it>/<it>Brca1 </it>double heterozygous cells were used to investigate DNA damage and repair, cell cycle, micronuclei, and cell transformation after photon irradiation.</p> <p>Results</p> <p>Remarkable high transformation frequency was confirmed in <it>Atm</it>/<it>Brca1 </it>double heterozygous cells compared to wild type cells. It was observed that delayed DNA damage recognition, disturbed cell cycle checkpoint, incomplete DNA repair, and increased genomic instability were involved in the biological networks. Haploinsufficiency of either ATM or BRCA1 negatively impacts these pathways.</p> <p>Conclusions</p> <p>The quantity of critical proteins such as ATM and BRCA1 plays an important role in determination of the fate of cells exposed to ionizing radiation and double heterozygosity increases the risk of tumorigenesis. These findings also benefit understanding of the individual susceptibility to tumor initiation.</p
Original Article Establishing a rapid animal model of osteoporosis with ovariectomy plus low calcium diet in rats
Abstract: The objective of this study was to rapidly develop osteoporotic model animals by combining ovariectomy with a low calcium diet in rats. Thirty, eight-week-old, female, Sprague-Dawley rats were either sham-operated (Sham) or ovariectomized (Ovx) and divided into three groups: Sham, Ovx, and Ovx + low calcium diet. Rats in the Sham and Ovx groups were fed a standard diet containing 1.1% w/w calcium while rats in the Ovx + low calcium diet group were fed a diet containing 0.1% w/w calcium. Serum osteocalcin and bone mineral density (BMD) of the lumbar vertebrae were measured 4 and 8 weeks after surgery. The rats were euthanized 12 weeks after surgery, and the BMD of the right femur and histomorphometry of the femoral neck were assessed at that time. The Ovx + low-calcium diet group had a significantly lower mean BMD of the lumbar vertebra and higher mean serum osteocalcin concentration than the Sham and Ovx groups. Twelve weeks after surgery, rats in the Ovx + low calcium diet group had a significantly lower BMD, smaller Tb.Th and Tb.N, and larger Tb.Sp of the right femoral neck than did rats in the Sham and Ovx groups. These data indicate that a low calcium diet can significantly accelerate bone loss in ovariectomized rats. Combining ovariectomy and a low calcium diet can save considerable time in the creation of osteoporotic model animals
ChimpACT: A Longitudinal Dataset for Understanding Chimpanzee Behaviors
Understanding the behavior of non-human primates is crucial for improving
animal welfare, modeling social behavior, and gaining insights into
distinctively human and phylogenetically shared behaviors. However, the lack of
datasets on non-human primate behavior hinders in-depth exploration of primate
social interactions, posing challenges to research on our closest living
relatives. To address these limitations, we present ChimpACT, a comprehensive
dataset for quantifying the longitudinal behavior and social relations of
chimpanzees within a social group. Spanning from 2015 to 2018, ChimpACT
features videos of a group of over 20 chimpanzees residing at the Leipzig Zoo,
Germany, with a particular focus on documenting the developmental trajectory of
one young male, Azibo. ChimpACT is both comprehensive and challenging,
consisting of 163 videos with a cumulative 160,500 frames, each richly
annotated with detection, identification, pose estimation, and fine-grained
spatiotemporal behavior labels. We benchmark representative methods of three
tracks on ChimpACT: (i) tracking and identification, (ii) pose estimation, and
(iii) spatiotemporal action detection of the chimpanzees. Our experiments
reveal that ChimpACT offers ample opportunities for both devising new methods
and adapting existing ones to solve fundamental computer vision tasks applied
to chimpanzee groups, such as detection, pose estimation, and behavior
analysis, ultimately deepening our comprehension of communication and sociality
in non-human primates.Comment: NeurIPS 202
Scalable and Programmable Phononic Network with Trapped Ions
Controllable bosonic systems can provide post-classical computational power
with sub-universal quantum computational capability. A network that consists of
a number of bosons evolving through beam-splitters and phase-shifters between
different modes, has been proposed and applied to demonstrate quantum
advantages. While the network has been implemented mostly in optical systems
with photons, recently alternative realizations have been explored, where major
limitations in photonic systems such as photon loss, and probabilistic
manipulation can be addressed. Phonons, the quantized excitations of
vibrational modes, of trapped ions can be a promising candidate to realize the
bosonic network. Here, we experimentally demonstrate a minimal-loss phononic
network that can be programmed and in which any phononic states are
deterministically prepared and detected. We realize the network with up to four
collective-vibrational modes, which can be straightforwardly extended to reveal
quantum advantage. We benchmark the performance of the network with an
exemplary algorithm of tomography for arbitrary multi-mode states with a fixed
total phonon number. We obtain reconstruction fidelities of 94.5 1.95 %
and 93.4 3.15 % for single-phonon and two-phonon states, respectively.
Our experiment demonstrates a clear and novel pathway to scale up a phononic
network for various quantum information processing beyond the limitations of
classical and other quantum systems
A method to prolong lithium-ion battery life during the full life cycle
Extended lifetime of lithium-ion batteries decreases economic costs and environmental burdens in achieving sustainable development. Cycle life tests are conducted on 18650-type commercial batteries, exhibiting nonlinear and inconsistent degradation. The accelerated fade dispersion is proposed to be triggered by the evolution of an additional potential of the anode during cycling as measured vs. Li/Li. A method to prolong the battery cycle lifetime is proposed, in which the lower cutoff voltage is raised to 3 V when the battery reaches a capacity degradation threshold. The results demonstrate a 38.1% increase in throughput at 70% of their beginning of life (BoL) capacity. The method is applied to two other types of lithium-ion batteries. A cycle lifetime extension of 16.7% and 33.7% is achieved at 70% of their BoL capacity, respectively. The proposed method enables lithium-ion batteries to provide long service time, cost savings, and environmental relief while facilitating suitable second-use applications
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