Search Results (60)

MicroRNAs (miRNAs) are small non-coding RNA molecules approximately 20–22 nucleotides in length that regulate gene expression at the post-transcriptional level. By binding to target messenger RNAs (mRNAs), miRNAs inhibit translation or induce degradation, thus influencing a wide array of biological processes including development, inflammation, apoptosis, and tissue remodeling. Owing to their remarkable stability and tissue specificity, miRNAs have emerged as promising biomarkers in both clinical and forensic settings. In recent years, increasing evidence has demonstrated their utility in cardiovascular diseases, where they may serve as diagnostic, prognostic, and therapeutic tools. This systematic review aims to comprehensively summarize the role of miRNAs in cardiovascular pathology, focusing on their diagnostic potential in myocardial infarction, sudden cardiac death (SCD), and cardiomyopathies, and their applicability in post-mortem investigations. Following PRISMA guidelines, we screened PubMed, Scopus, and Web of Science databases for studies up to December 2024. The results highlight several miRNAs—including miR-1, miR-133a, miR-208b, miR-499a, and miR-486-5p—as robust markers for ischemic injury and sudden death, even in degraded or formalin-fixed autopsy samples. The high stability of miRNAs under extreme post-mortem conditions reinforces their potential as molecular tools in forensic pathology. Nevertheless, methodological heterogeneity and limited standardization currently hinder their routine application. Future studies should aim to harmonize analytical protocols and validate diagnostic thresholds across larger, well-characterized cohorts to fully exploit miRNAs as reliable molecular biomarkers in both clinical cardiology and forensic medicine. Full article

The design of low-complexity and efficient constrained codes has been a major research item for many years. This paper reports on a versatile method named concatenated constrained codes for designing efficient fixed-length constrained codes with small complexity. A concatenated constrained code comprises two (or more) cooperating constrained codes of low complexity enabling long constrained codes that are not practically feasible with prior art methods. We apply the concatenated coding approach to two case studies, namely the design of constant-weight and low-weight codes. In a binary constant-weight code, each codeword has the same number, w, of 1’s, where w is called the weight of a codeword. We specifically focus on the trading between coder complexity and redundancy. Full article

Deep and ultra-deep drilling operations commonly encounter fractured and fracture-vuggy formations, where weak wellbore strength and well-developed fracture networks lead to frequent lost circulation, presenting a key challenge to safe and efficient drilling. Existing diagnostic practices mostly rely on drilling fluid loss dynamic models of single fractures or simplified discrete fractures to invert fracture geometry, which cannot capture the spatiotemporal evolution of loss in complex fracture networks, resulting in limited inversion accuracy and a lack of quantitative, fracture-network-based loss-dynamics support for bridge-plugging design. In this study, a geologically realistic wellbore–fracture-network coupled loss dynamic model is constructed to overcome the limitations of single- or simplified-fracture descriptions. Within a unified computational fluid dynamics (CFD) framework, solid–liquid two-phase flow and Herschel–Bulkley rheology are incorporated to quantitatively characterise fracture connectivity. This approach reveals how instantaneous and steady losses are controlled by key geometrical factors, thereby providing a computable physical basis for loss-zone inversion and bridge-plugging design. Validation against experiments shows a maximum relative error of 7.26% in pressure and loss rate, indicating that the model can reasonably reproduce actual loss behaviour. Different encounter positions and node types lead to systematic variations in loss intensity and flow partitioning. Compared with a single fracture, a fracture network significantly amplifies loss intensity through branch-induced capacity enhancement, superposition of shortest paths, and shortening of loss paths. In a typical network, the shortest path accounts for only about 20% of the total length, but contributes 40–55% of the total loss, while extending branch length from 300 mm to 1500 mm reduces the steady loss rate by 40–60%. Correlation analysis shows that the instantaneous loss rate is mainly controlled by the maximum width and height of fractures connected to the wellbore, whereas the steady loss rate has a correlation coefficient of about 0.7 with minimum width and effective path length, and decreases monotonically with the number of connected fractures under a fixed total width, indicating that the shortest path and bottleneck width are the key geometrical factors governing long-term loss in complex fracture networks. This work refines the understanding of fractured-loss dynamics and proposes the concept of coupling hydraulic deviation codes with deep learning to build a mapping model from mud-logging curves to fracture geometrical parameters, thereby providing support for lost-circulation diagnosis and bridge-plugging optimisation in complex fractured formations. Full article

Explanations for static-analysis warnings assist developers in understanding potential code issues. An end-to-end pipeline was implemented to generate natural-language explanations, evaluated on 5183 warning–explanation pairs from Java repositories, including a manually validated gold subset of 1176 examples for faithfulness assessment. Explanations were produced by a transformer-based encoder–decoder model (CodeT5) conditioned on warning types, contextual code snippets, and static-analysis evidence. Initial experiments employed single-objective optimization for hyperparameters (using a genetic algorithm with dynamic search-space correction, which adaptively adjusted search bounds based on the evolving distribution of candidate solutions, clustering promising regions, and pruning unproductive ones), but this approach enforced a fixed faithfulness–fluency trade-off; therefore, a multi-objective evolutionary algorithm (NSGA-II) was adopted to jointly optimize both criteria. Pareto-optimal configurations improved normalized faithfulness by up to 12% and textual quality by 5–8% compared to baseline CodeT5 settings, with batch sizes of 10–21, learning rates $2.3\times {10}^{-5}$ to $5\times {10}^{-4}$, maximum token lengths of 36–65, beam width 5, length penalty 1.15, and nucleus sampling $p=0.88$. Candidate explanations were reranked using a composite score of likelihood, faithfulness, and code-usefulness, producing final outputs in under 0.001 s per example. The results indicate that structured conditioning, evolutionary hyperparameter search, and reranking yield explanations that are both aligned with static-analysis evidence and linguistically coherent. Full article

Let e be a fixed positive integer and $n_1,n_2$ be odd positive integers. The main objective of this article is to investigate the algebraic structure of double cyclic codes of length $(n_1,n_2)$ over the finite chain ring ${}_e\mathcal{R} = F_{4^e}+v{F}_{4^e}$, where $v^2=0$. Building upon this structural framework, we further demonstrate the construction of DNA codes derived from these double cyclic codes over ${}_e\mathcal{R}$. In addition, we provide the necessary and sufficient criteria showing that these codes possess reversibility and reverse-complement properties over ${}_e\mathcal{R}$. Furthermore, we introduce a generalized Gray map that extends the classical Gray map from the ring $F_2+v{F}_2$ with $v^2=0$ to the ring ${}_e\mathcal{R}$, showing a direct correspondence between elements of ${}_e\mathcal{R}$ and DNA sequences over $S=\{A,T,G,C\}$ utilizing double cyclic codes. To illustrate the applicability of our results, we present some examples demonstrating the effectiveness of the mapping in generating reversible and reverse-complement DNA codes from algebraic structures over the ring ${}_e\mathcal{R}$. Full article

Symmetric cryptography is essential for secure communication as it ensures confidentiality by using shared secret keys. This paper proposes a novel substitution-permutation network (SPN) that integrates Latin squares, permutations, and Reed-Muller (RM) codes to achieve robust security and resilience. As an adaptive design using binary representation with base-n Latin square mappings for non-linear substitutions, it supports any n (Codeword length and Latin square order), k (RM code dimension), d (RM code minimum distance) parameters aligned with the Latin square and $\mathrm{RM}(n,k,d)$ codes. The scheme employs $2{log}_{2}n$-round transformations using ${log}_{2}n$ permutations ${\rho }_z$, where in the additional ${log}_{2}n$ rounds, row and column pairs are swapped for each pair of rounds, with key-dependent ${\pi }_z$ permutations for round outputs and fixed ${\rho }_z$ permutations for codeword shuffling, ensuring strong diffusion. The scheme leverages dynamic Latin square substitutions for confusion and a vast key space, with permutations ensuring strong diffusion and $\mathrm{RM}(n,k,d)$ codes correcting transmission errors and enhancing robustness against fault-based attacks. Precomputed components optimize deployment efficiency. The paper presents mathematical foundations, security primitives, and experimental results, including avalanche effect analysis, demonstrating flexibility and balancing enhanced security with computational and storage overhead. Full article

In quantum key distribution (QKD), public discussion over the authenticated classical channel inevitably leaks information about the raw key to a potential adversary, which must later be mitigated by privacy amplification. To limit this leakage, a one-time pad (OTP) has been proposed to protect message exchanges in various settings. Building on the security proof of Tomamichel and Leverrier, which is based on a non-asymptotic framework and considers the effects of finite resources, we extend the analysis to the OTP-protected scheme. We show that when the OTP key is drawn from the entropy pool of the same QKD session, the achievable quantum key rate is identical to that of the reference protocol with unprotected error-correction exchange. This equivalence holds for a fixed security level, defined via the diamond distance between the real and ideal protocols modeled as completely positive trace-preserving maps. At the same time, the proposed approach reduces the computational requirements: for non-interactive low-density parity-check codes, the encoding problem size is reduced by the square of the syndrome length, while privacy amplification requires less compression. The technique preserves security, avoids the use of QKD keys between sessions, and has the potential to improve performance. Full article

The hull of a linear code C is the intersection of C with its dual code. The goal is to study the dimensions of the hulls of optimal binary and ternary linear codes for a given length and dimension. The focus is on the lengths at which self-orthogonal (respectively, LCD) optimal codes exist at fixed dimension. Full article

This paper investigates point-to-point multimodal digital semantic communications in a task-oriented setup, where messages are classified at the receiver. We employ a pre-trained transformer model to extract semantic information and propose three methods for generating semantic codewords. First, we propose semantic quantization that uses quantized embeddings of source realizations as a codebook. We investigate the fixed-length coding, considering the source semantic structure and end-to-end semantic distortion. We propose a neural network-based codeword assignment mechanism incorporating codeword transition probabilities to minimize the expected semantic distortion. Second, we present semantic compression that clusters embeddings, exploiting the inherent semantic redundancies to reduce the codebook size, i.e., further compression. Third, we introduce a semantic vector-quantized autoencoder (VQ-AE) that learns a codebook through training. In all cases, we follow this semantic source code with a standard channel code to transmit over the wireless channel. In addition to classification accuracy, we assess pre-communication overhead via a novel metric we term system time efficiency. Extensive experiments demonstrate that our proposed semantic source-coding approaches provide comparable accuracy and better system time efficiency compared to their learning-based counterparts. Full article

Benchmark results for large language models often show inconsistencies across different studies. This paper investigates the challenges of reproducing these results in automatic bugfixing using LLMs, on the HumanEvalFix benchmark. To determine the cause of the differing results in the literature, we attempted to reproduce a subset of them by evaluating 12 models in the DeepSeekCoder, CodeGemma, CodeLlama, and WizardCoder model families, in different sizes and tunings. A total of 35 unique results were reported for these models across studies, of which we successfully reproduced 12. We identified several relevant factors that influenced the results. The base models can be confused with their instruction-tuned variants, making their results better than expected. Incorrect prompt templates or generation length can decrease benchmark performance, as well as using 4-bit quantization. Using sampling instead of greedy decoding can increase the variance, especially with higher temperature values. We found that precision and 8-bit quantization have less influence on benchmark results. Full article

In modern communication technology, short videos are increasingly used on social media platforms. The advancement of video codecs is pivotal in communication. In this study, we developed a new scheme to encode the residue of intraframes. For the H.264 baseline profile, we used context-based arithmetic variable-length coding (CAVLC) to encode the residue of integer transforms in a block-wise manner. In the developed method, the DC and AC coefficients are separated. In addition, context assignment, adaptive scanning, range increment, and mutual learning are adopted in a mixture of fixed-length and variable-length schemes, and block-wise compressions of the frequency table are applied to obtain improved compression rates. Compressing the frequency prevents CAVLC from being hindered by horizontally/vertically dominated blocks. The developed method outperforms CAVLC, with average reductions of 7.81, 8.58, and 7.88% in quarter common intermediate format (QCIF), common intermediate format (CIF), and full high-definition (FHD) inputs. Full article

Lossless image compression has been studied and widely applied, particularly in medicine, space exploration, aerial photography, and satellite communication. In this study, we proposed a low-complexity lossless compression for image (LOCO-I) predictor based on the joint photographic expert group–lossless standard (JPEG-LS). We analyzed the nature of the LOCO-I predictor and offered possible solutions. The improved LOCO-I outperformed LOCO-I by a reduction of 2.26% in entropy for the full image size and reductions of 2.70, 2.81, and 2.89% for 32 × 32, 16 × 16, and 8 × 8 block-based compression, respectively. In addition, we suggested vertical/horizontal flip for block-based compression, which requires extra bits to record and decreases the entropy. Compared with other state-of-the-art (SOTA) lossless image compression predictors, the proposed method has low computation complexity as it is multiplication- and division-free. The model is also better suited for hardware implementation. As the predictor exploits no inter-block relation, it enables parallel processing and random access if encoded by fix-length coding (FLC). Full article

A de Bruijn sequence of order k over a finite alphabet is a cyclic sequence with the property that it contains every possible k-sequence as a substring exactly once. Orthogonal de Bruijn sequences are the collections of de Bruijn sequences of the same order, k, that satisfy the joint constraint that every $(k+1)$-sequence appears as a substring in, at most, one of the sequences in the collection. Both de Bruijn and orthogonal de Bruijn sequences have found numerous applications in synthetic biology, although the latter remain largely unexplored in the coding theory literature. Here, we study three relevant practical generalizations of orthogonal de Bruijn sequences, where we relax either the constraint that every $(k+1)$-sequence appears exactly once or the sequences themselves are de Bruijn rather than balanced de Bruijn sequences. We also provide lower and upper bounds on the number of fixed-weight orthogonal de Bruijn sequences. The paper concludes with parallel results for orthogonal nonbinary Kautz sequences, which satisfy similar constraints as de Bruijn sequences, except for being only required to cover all subsequences of length k whose maximum run length equals one. Full article

In this work, we report the draft genome sequence of Ensifer sp. P24N7, a symbiotic nitrogen-fixing bacterium isolated from nodules of Phaseolus vulgaris var. Negro Jamapa was planted in pots that contained mining tailings from Huautla, Morelos, México. The genomic DNA was sequenced by an Illumina NovaSeq 6000 using the 250 bp paired-end protocol obtaining 1,188,899 reads. An assembly generated with SPAdes v. 3.15.4 resulted in a genome length of 7,165,722 bp composed of 181 contigs with a N50 of 323,467 bp, a coverage of 76X, and a GC content of 61.96%. The genome was annotated with the NCBI Prokaryotic Genome Annotation Pipeline and contains 6631 protein-coding sequences, 3 complete rRNAs, 52 tRNAs, and 4 non-coding RNAs. The Ensifer sp. P24N7 genome has 59 genes related to heavy metal tolerance predicted by RAST server. These data may be useful to the scientific community because they can be used as a reference for other works related to heavy metals, including works in Huautla, Morelos. Full article

Smart contracts are at the core of blockchain technology, but the cost of fixing their security vulnerabilities is high, making pre-deployment vulnerability detection crucial. Existing methods rely on fixed rules, which have limitations in accuracy and scalability, and their efficiency decreases with the complexity of the rules. Neural-network-based methods can identify some vulnerabilities but are inefficient in multi-vulnerability scenarios and depend on source code. To address these issues, we propose a multi-vulnerability-based smart contract detection method called RTMS. RTMS takes bytecode as input, disassembles it into opcodes, uses the gas consumed by the contract for data slicing, and extends the length of input opcodes through a layered structure. It employs a weighted binary cross-entropy (BCE) function to handle data imbalance and combines channel-sequence attention mechanisms to extract vulnerability correlation features. By using transfer learning, it reduces training parameters and computational costs. Our RTMS model can detect multiple vulnerabilities simultaneously, enhancing detection accuracy and efficiency. In experiments with 100,000 real contract samples, the model achieved a Jaccard coefficient of 0.9312, a Hamming loss of 0.0211, and an F1 score that improved by about 11 percentage points compared to existing models, demonstrating its superiority and stability. Full article