Deep learning (DL)-based channel state information (CSI) feedback provides satisfactory reconstruction accuracy of downlink CSI for the base station in massive multiple-input multiple-output (MIMO) ...systems. Although the introduction of codeword quantization improves the efficiency and feasibility of DL-based CSI feedback networks, the gradient problem caused by quantizers in the training stage compromises the performance of neural networks. In this paper, by considering the test channel as an equivalent of ideal rate-distortion quantization in a mutual information sense, we propose a test channel-based quantization module (TCQM) for DL-based CSI feedback networks which mitigates the gradient problem in the end-to-end training of CSI feedback networks. Moreover, the training of the CSI feedback network with TCQM is not dependent on the design of practical quantizer in the inference stage, which reduces the complexity of the training and design constraints of the CSI feedback system. Finally, for the setting of fixed feedback overhead, based on the idea of TCQM, we propose an adaptive training strategy for CSI feedback networks to evaluate the proper combination of codeword length and quantization rate of codeword elements to achieve the optimal reconstruction accuracy. Experiment results show that the proposed schemes outperform existing codeword quantization schemes in the literature.
A secure multi-party batch matrix multiplication problem (SMBMM) is considered, where the goal is to allow a master to efficiently compute the pairwise products of two batches of massive matrices, by ...distributing the computation across S servers. Any X colluding servers gain no information about the input, and the master gains no additional information about the input beyond the product. A solution called Generalized Cross Subspace Alignment codes with Noise Alignment (GCSA- NA) is proposed in this work, based on cross-subspace alignment codes. The state of art solution to SMBMM is a coding scheme called polynomial sharing (PS) that was proposed by Nodehi and Maddah-Ali. GCSA-NA outperforms PS codes in several key aspects-more efficient and secure inter-server communication, lower latency, flexible inter-server network topology, efficient batch processing, and tolerance to stragglers. The idea of noise alignment can also be combined with N-source Cross Subspace Alignment (N-CSA) codes and fast matrix multiplication algorithms like Strassen's construction. Moreover, noise alignment can be applied to symmetric secure private information retrieval to achieve the asymptotic capacity.
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•A concise asymmetric total synthesis of (+)-fawcettimine.•Construction of 6–5-9 tricycle via a novel strategy.•Pd-mediated cycloalkenylation to assemble cis-fused 6–5 bicycle.•An ...Oxa-Diels-Alder reaction to introduce the side chain.
A straightforward and stereocontrolled total synthesis of (+)-fawcettimine was accomplished from the known (R)-5-methyl-2-cyclohexen-one in 11 steps. The synthesis features a palladium mediated cycloalkenylation of a silyl enol ether for assembling the 6/5-hydrindane system and generating a quaternary carbon center in one step; an oxa-Diels-Alder reaction followed by a Mitsunobu reaction to construct the Heathecock intermediate, i.e., the 6–5-9 tricycle skeleton.
MiR-499 is a cardiac-abundant miRNA. However, the biological functions of miR-499 in differentiated cardiomyocytes or in the cardiomyocyte differentiation process is not very clear. Sox6 is believed ...to be one of its targets, and is also believed to play a role in cardiac differentiation. Therefore, our aim was to investigate the association between Sox6 and miR-499 during cardiac differentiation.
Using a well-established in vitro cardiomyocyte differentiation system, mouse P19CL6 cells, we found that miR-499 was highly expressed in the late stage of cardiac differentiation. In cells stably transfected with miR-499 (P-499 cells), it was found that miR-499 could promote the differentiation into cardiomyocytes at the early stage of cardiac differentiation. Notably, cell viability assay, EdU incorporation assay, and cell cycle profile analysis all showed that the P-499 cells displayed the distinctive feature of hyperplastic growth. Further investigation confirmed that miR-499 could promote neonatal rat cardiomyocyte proliferation. MiR-499 knock-down enhanced apoptosis in the late differentiation stage in P19CL6 cells, but overexpression of miR-499 resulted in a decrease in the apoptosis rate. Sox6 was identified as a direct target of miR-499 and its expression was detected from day 8 or day 10 of cardiac differentiation of P19CL6 cells. Sox6 played a role in cell viability, inhibited cell proliferation and promoted cell apoptosis in P19CL6 cells and cardiomyocytes. The overexpression of Sox6 could reverse the proliferation and anti-apoptosis effects of miR-499. It was also found that miR-499 might exert its function by regulating cyclin D1 via its influence on Sox6.
miR-499 probably regulates the proliferation and apoptosis of P19CL6 cells in the late stage of cardiac differentiation via its effects on Sox6 and cyclin D1.
Sepsis-induced cardiac apoptosis is one of the major pathogenic factors in myocardial dysfunction. As it enhances numerous proinflammatory factors, lipopolysaccharide (LPS) is considered the ...principal mediator in this pathological process. However, the detailed mechanisms involved are unclear. In this study, we attempted to explore the mechanisms involved in LPS-induced cardiomyocyte apoptosis. We found that LPS stimulation inhibited microRNA (miR)-499 expression and thereby upregulated the expression of
SOX6
and
PDCD4
in neonatal rat cardiomyocytes. We demonstrate that
SOX6
and
PDCD4
are target genes of miR-499, and they enhance LPS-induced cardiomyocyte apoptosis by activating the BCL-2 family pathway. The apoptosis process enhanced by overexpression of
SOX6
or
PDCD4
, was rescued by the cardiac-abundant miR-499. Overexpression of miR-499 protected the cardiomyocytes against LPS-induced apoptosis. In brief, our results demonstrate the existence of a miR-499-
SOX6
/
PDCD4
-BCL-2 family pathway in cardiomyocytes in response to LPS stimulation.
Double Blind T-Private Information Retrieval Lu, Yuxiang; Jia, Zhuqing; Jafar, Syed A.
IEEE journal on selected areas in information theory,
03/2021, Volume:
2, Issue:
1
Journal Article
Peer reviewed
Open access
Double blind <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula>-private information retrieval (DB-TPIR) enables two users, each of whom specifies an index (<inline-formula> ...<tex-math notation="LaTeX">\theta _{1}, \theta _{2} </tex-math></inline-formula>, resp.), to efficiently retrieve a message <inline-formula> <tex-math notation="LaTeX">W(\theta _{1},\theta _{2}) </tex-math></inline-formula> labeled by the two indices, from a set of <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula> servers that store all messages <inline-formula> <tex-math notation="LaTeX">W(k_{1},k_{2}), k_{1}\in \{1,2,\ldots, K_{1}\}, k_{2}\in \{1,2,\ldots, K_{2}\} </tex-math></inline-formula>, such that the two users' indices are kept private from any set of up to <inline-formula> <tex-math notation="LaTeX">T_{1},T_{2} </tex-math></inline-formula> colluding servers, respectively, as well as from each other. A DB-TPIR scheme based on cross-subspace alignment is proposed in this paper, and shown to be capacity-achieving in the asymptotic setting of large number of messages and bounded latency. The scheme is then extended to <inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula>-way blind <inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula>-secure <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula>-private information retrieval (MB-XS-TPIR) with multiple (<inline-formula> <tex-math notation="LaTeX">M </tex-math></inline-formula>) indices, each belonging to a different user, arbitrary privacy levels for each index (<inline-formula> <tex-math notation="LaTeX">T_{1}, T_{2},\ldots, T_{M} </tex-math></inline-formula>), and arbitrary level of security (<inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula>) of data storage, so that the message <inline-formula> <tex-math notation="LaTeX">W(\theta _{1},\theta _{2},\ldots, \theta _{M}) </tex-math></inline-formula> can be efficiently retrieved while the stored data is held secure against collusion among up to <inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula> colluding servers, the <inline-formula> <tex-math notation="LaTeX">m^{th} </tex-math></inline-formula> user's index is private against collusion among up to <inline-formula> <tex-math notation="LaTeX">T_{m} </tex-math></inline-formula> servers, and each user's index <inline-formula> <tex-math notation="LaTeX">\theta _{m} </tex-math></inline-formula> is private from all other users. The general scheme relies on a tensor-product based extension of cross-subspace alignment and retrieves <inline-formula> <tex-math notation="LaTeX">1-(X+T_{1}+\cdots +T_{M})/N </tex-math></inline-formula> bits of desired message per bit of download.
ISL1 is expressed in cardiac progenitor cells and plays critical roles in cardiac lineage differentiation and heart development. Cardiac progenitor cells hold great potential for clinical and ...translational applications. However, the mechanisms underlying ISL1 function in cardiac progenitor cells have not been fully elucidated. Here we uncover a hierarchical role of ISL1 in cardiac progenitor cells, showing that ISL1 directly regulates hundreds of potential downstream target genes that are implicated in cardiac differentiation, through an epigenetic mechanism. Specifically, ISL1 promotes the demethylation of tri-methylation of histone H3K27 (H3K27me3) at the enhancers of key downstream target genes, including Myocd and Mef2c, which are core cardiac transcription factors. ISL1 physically interacts with JMJD3, a H3K27me3 demethylase, and conditional depletion of JMJD3 leads to impaired cardiac progenitor cell differentiation, phenocopying that of ISL1 depletion. Interestingly, ISL1 is not only responsible for the recruitment of JMJD3 to specific target loci during cardiac progenitor differentiation, but also modulates its demethylase activity. In conclusion, ISL1 and JMJD3 partner to alter the cardiac epigenome, instructing gene expression changes that drive cardiac differentiation.
Mesenchymal stem cells (MSCs) isolated from bone marrow (BM), cartilage, and adipose tissue (AT) possess the capacity for self-renewal and the potential for multilineage differentiation, and are ...therefore perceived as attractive sources of stem cells for cell therapy. However, MSCs from these different sources have different characteristics. We compared MSCs of adult Sprague Dawley rats derived from these three sources in terms of their immunophenotypic characterization, proliferation capacity, differentiation ability, expression of angiogenic cytokines, and anti-apoptotic ability. According to growth curve, cell cycle, and telomerase activity analyses, MSCs derived from adipose tissue (AT-MSCs) possess the highest proliferation potential, followed by MSCs derived from BM and cartilage (BM-MSCs and C-MSCs). In terms of multilineage differentiation, MSCs from all three sources displayed osteogenic, adipogenic, and chondrogenic differentiation potential. The result of realtime RT-PCR indicated that these cells all expressed angiogenic cytokines, with some differences in expression level. Flow cytometry and MTT analysis showed that C-MSCs possess the highest resistance toward hydrogen peroxide -induced apoptosis, while AT-MSCs exhibited high tolerance to serum deprivation-induced apoptosis. Both AT and cartilage are attractive alternatives to BM as sources for isolating MSCs, but these differences must be considered when choosing a stem cell source for clinical application.
We consider the problem of X-secure and T-private linear computation with graph based replicated storage (GXSTPLC), which enables the user to privately retrieve a linear combination of messages from ...a set of N distributed servers where each message is restricted to be stored exclusively among a subset of servers, adhering to an X-security constraint. This constraint dictates that any group of up to X colluding servers must not disclose any information about the stored messages. Furthermore, any group of up to T servers is restricted from learning anything about the coefficients of the linear combination retrieved by the user. In this work, we completely characterize the asymptotic capacity of GXSTPLC, i.e., the supremum of achievable rates (which is the average number of desired symbols retrieved per downloaded symbol), in the limit as the number of messages K approaches infinity. Specifically, it is shown that a prior linear programming based upper bound on the asymptotic capacity of GXSTPLC due to Jia and Jafar is tight (thus settles their conjecture) by constructing achievability schemes. Notably, our achievability scheme also settles the exact capacity (i.e., for finite K) of X-secure linear combination with graph based replicated storage (GXSLC). Our achievability proof builds upon an achievability scheme for a closely related problem named asymmetric <inline-formula> <tex-math notation="LaTeX">\mathbf {X} </tex-math></inline-formula>-secure <inline-formula> <tex-math notation="LaTeX">\mathbf {T} </tex-math></inline-formula>-private linear computation with graph based replicated storage (Asymm-GXSTPLC) that guarantees non-uniform security and privacy levels across messages and coefficients (of the desired linear combination). In particular, by carefully designing Asymm-GXSTPLC settings for GXSTPLC problems, the corresponding Asymm-GXSTPLC schemes can be reduced to asymptotic capacity achieving schemes for GXSTPLC. In regard to the achievability scheme for Asymm-GXSTPLC, interesting aspects of our construction include a novel query and answer design which makes use of a Vandermonde decomposition of Cauchy matrices, and a trade-off among message replication, security and privacy thresholds.
The problem of <inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula>-secure <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula>-private information ...retrieval from MDS coded storage is studied in this paper, where the user wishes to privately retrieve one out of <inline-formula> <tex-math notation="LaTeX">K </tex-math></inline-formula> independent messages that are distributed over <inline-formula> <tex-math notation="LaTeX">N </tex-math></inline-formula> servers according to an MDS code. It is guaranteed that any group of up to <inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula> colluding servers learn nothing about the messages and that any group of up to <inline-formula> <tex-math notation="LaTeX">T </tex-math></inline-formula> colluding servers learn nothing about the identity of desired message. A lower bound of achievable rates is proved by presenting a novel scheme based on cross-subspace alignment and a successive decoding with interference cancellation strategy. For large number of messages <inline-formula> <tex-math notation="LaTeX">(K\rightarrow \infty) </tex-math></inline-formula> the achieved rate, which we conjecture to be optimal, improves upon the best known rates previously reported in the literature by Raviv and Karpuk, and generalizes an achievable rate for MDS-TPIR previously found by Freij-Hollanti et al. that is also conjectured to be asymptotically optimal. The setting is then expanded to allow unresponsive and Byzantine servers. Finally, the scheme is applied to find a new lower convex hull of (download, upload) pairs of secure and private distributed matrix multiplication that generalizes, and in certain asymptotic settings strictly improves upon the best known previous results.
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