Search Results (16)

Deep learning methods have achieved remarkable success in remote sensing object detection. Existing object detection methods focus on integrating convolutional neural networks (CNNs) and Transformer networks to explore local and global representations to improve performance. However, existing methods relying on fixed convolutional kernels and dense global attention mechanisms suffer from computational redundancy and insufficient discriminative feature extraction, particularly for small and rotation-sensitive targets. To address these limitations, we propose a Dynamic Multi-Kernel Position-Aware Feature Pyramid Network (PAMFPN), which integrates adaptive sparse position modeling and multi-kernel dynamic fusion to achieve robust feature representation. Firstly, we design a position-interactive context module (PICM) that incorporates distance-aware sparse attention and dynamic positional encoding. It selectively focuses computation on sparse targets through a decay function that suppresses background noise while enhancing spatial correlations of critical regions. Secondly, we design a dual-kernel adaptive fusion (DKAF) architecture by combining region-sensitive attention (RSA) and reconfigurable context aggregation (RCA). RSA employs orthogonal large-kernel convolutions to capture anisotropic spatial features for arbitrarily oriented targets, while RCA dynamically adjusts the kernel scales based on content complexity, effectively addressing scale variations and intraclass diversity. Extensive experiments on three benchmark datasets (DOTA-v1.0, SSDD, HWPUVHR-10) demonstrate the effectiveness and versatility of the proposed PAMFPN. This work bridges the gap between efficient computation and robust feature fusion in remote sensing detection, offering a universal solution for real-world applications. Full article

Rolling circle amplification (RCA) at ambient temperature is prone to false positive signals during nucleic acid detection, which makes it challenging to establish an efficient RCA detection method. The false positive signals are primarily caused by binding of non-target nucleic acids to the circular single-stranded template, leading to non-specific amplification. Here, we present an RCA method for miRNA detection at 37 °C using two circular ssDNAs, each of which is formed by ligating the intramolecularly formed nick (without any splint) in a secondary structure. The specific target recognition is realized by utilizing low concentrations (0.1 nM) of circular ssDNA1 (C1). A phosphorothioate modification is present at G*AATTC on C1 to generate a nick for primer extension during the primer self-generated rolling circle amplification (PG-RCA). The fragmented amplification products are used as primers for the following RCA that serves as signal amplification using circular ssDNA2 (C2). Notably, the absence of splints and the low concentration of C1 significantly inhibits non-target binding, thus minimizing false positive signals. A high concentration (10 nM) of C2 is used to carry out linear rolling circle amplification (LRCA), which is highly specific. This strategy demonstrates a good linear response to 0.01–100 pM of miRNA with a detection limit of 7.76 fM (miR-155). Moreover, it can distinguish single-nucleotide mismatch in the target miRNA, enabling the rapid one-pot detection of miRNA at 37 °C. Accordingly, this method performs with high specificity and sensitivity. This approach is suitable for clinical serum sample analysis and offers a strategy for developing specific biosensors and diagnostic tools. Full article

The Dual Carry Approximate Adder (DCAA) is proposed as an advanced 8-bit approximate adder featuring dual carry-out and carry-in full adders (FAs) along with an Error Reduction Unit (ERU) to enhance accuracy. The 8-bit adder is partitioned into upper and lower 4-bit blocks, connected via a dual carry-out full adder and a dual carry-in full adder. To minimize impact on the critical path, an ERU is designed for efficient error correction. Four variants of the DCAA are provided, allowing users to select the most suitable design based on their specific power, area, and accuracy requirements. The DCAA achieves a 78% reduction in Mean Error Distance (MED) while maintaining high computational speed and efficiency. When applied to Wallace Tree multipliers, it reduces delay by 32% compared to ripple carry adders (RCAs), and in in-memory computing (IMC) architectures, it significantly improves accuracy with minimal delay overhead. Experimental results demonstrate that the DCAA offers a well-balanced trade-off between accuracy, speed, and resource efficiency, making it suitable for high-performance, error-tolerant applications. Compared to existing approximate adders, DCAA exhibits superior error correction capabilities while achieving significantly lower delay. Furthermore, its efficient hardware implementation enables seamless integration into various computing paradigms, including AI accelerators and neuromorphic processors. Additionally, the scalability of the design allows for flexible adaptation to different bit-widths, making it a versatile solution for next-generation computing architectures. Full article

Background and Objectives: Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established technique for evaluating myocardial perfusion and function in patients with suspected or known coronary artery disease. While conventional dual-detector SPECT scanners have limitations in spatial resolution and photon detection sensitivity, recent advancements, including full-ring solid-state cadmium zinc telluride (CZT) detectors, offer enhanced image quality and improved diagnostic accuracy. This study aimed to compare the performance of Veriton-CT, a full-ring CZT SPECT system, with GE Discovery 530c, a dedicated cardiac fixed-angle gamma camera, in myocardial perfusion imaging and their correlation with coronary angiography findings. Materials and Methods: This was a prospective study that analyzed 21 patients who underwent MPI at the Department of Nuclear Medicine, Lithuanian University of Health Sciences, Kauno Klinikos. A one-day stress–rest protocol using 99mTc-Sestamibi was employed, with stress testing performed via bicycle ergometry or pharmacological induction. MPI was first conducted using GE Discovery 530c (GE Health Care, Boston, MA, USA), followed by imaging on Veriton-CT, which included low-dose CT for attenuation correction. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were analyzed and compared between both imaging modalities. Coronary angiography results were retrospectively collected, and lesion-based analysis was performed to assess the correlation between imaging results and the presence of significant coronary artery stenosis (≥35% and ≥70% narrowing). Image quality and the certainty of distinguishing the inferior myocardial wall from extracardiac structures were also evaluated by two independent researchers with differing levels of experience. Results: Among the 14 patients included in the final analysis, Veriton-CT was more likely to classify MPI scans as normal (64.3%) compared to GE Discovery 530c (28.6%). Additionally, Veriton-CT provided a better assessment of the right coronary artery (RCA) basin, showing greater agreement with coronary angiography findings than GE Discovery 530c, although the difference was not statistically significant. No significant differences in lesion overlap were observed for the left anterior descending artery (LAD) or left circumflex artery (LCx) basins. Furthermore, the image quality assessment revealed slightly better delineation of extracardiac structures using Veriton-CT (Spectrum Dynamics Medical, Caesarea, Israel), particularly when evaluated by an experienced researcher. However, no significant difference was observed when assessed by a less experienced observer. Conclusions: Our findings suggest that Veriton-CT, with its full-ring CZT detector system, may offer advantages over fixed-angle gamma cameras in improving image quality and reducing attenuation artifacts in MPI. Although the difference in correlations with coronary angiography findings was not statistically significant, Veriton-CT showed a trend toward better agreement, particularly in the RCA basin. These results indicate that full-ring SPECT imaging could improve the diagnostic accuracy of non-invasive MPI, potentially reducing the need for unnecessary invasive angiography. Further studies with larger patient cohorts are required to confirm these findings and evaluate the clinical impact of full-ring SPECT technology in myocardial perfusion imaging. Full article

Background: ST-segment elevation myocardial infarction (STEMI) remains a leading cause of mortality worldwide, primarily caused by acute thrombosis over atherosclerotic plaques. Simultaneous acute thrombosis in two coronary arteries is an exceptionally rare event. This report highlights a unique case of STEMI associated with cardiogenic shock due to dual coronary artery thrombosis and provides insights from a literature review on this rare condition. Methods: We report the case of a 58-year-old male with a history of hypertension, type II diabetes, and heavy smoking, who presented with a two-day history of chest pain and cardiogenic shock. Diagnostic evaluation included an electrocardiogram showing ST-segment elevation in AVR and ischemia, along with echocardiography revealing severe left ventricular dysfunction (ejection fraction 20%). Emergency coronary angiography was performed to identify the underlying pathology. Additionally, a literature review was conducted to analyze the characteristics and outcomes of similar cases of dual coronary artery thrombosis. Results: Coronary angiography identified significant occlusions in the proximal circumflex branch and the left anterior descending artery (LAD), a combination rarely reported in the literature. Our review confirmed that dual thrombosis involving the LAD and right coronary artery (RCA) is the most frequently described presentation of this condition, while simultaneous CFX and LAD thrombosis is exceedingly rare. Most reported cases, including ours, were associated with cardiogenic shock, highlighting the severity of this clinical entity. Despite successful thrombus aspiration and stenting, our patient experienced severe complications, including infections, pleural effusions, and paralytic ileus, ultimately requiring evaluation for left ventricular assist device implantation. Conclusions: This case underscores the complexity and critical challenges of managing STEMI with cardiogenic shock due to simultaneous coronary thrombosis. The findings from our literature review suggest the need for heightened clinical awareness and tailored revascularization strategies. Further studies are warranted to optimize management approaches and improve outcomes in such rare and high-risk scenarios. Full article

Single nucleotide polymorphisms (SNPs) present significant challenges in microbial detection and treatment, further raising the demands on sequencing technologies. In response to these challenges, we have developed a novel barcode-based approach for highly sensitive single nucleotide recognition. This method leverages a dual-head folded complementary template probe in conjunction with DNA ligase to specifically identify the target base. Upon recognition, the system triggers rolling circle amplification (RCA) followed by the self-assembly of CdSe quantum dots onto polystyrene microspheres, enabling a single-particle fluorescence readout. This approach allows for precise base identification at individual loci, which are then analyzed using a bio-barcode array to screen for base changes across multiple sites. This method was applied to sequence a drug-resistant mutation site in Helicobacter pylori (H. pylori), demonstrating excellent accuracy and stability. Offering high precision, high sensitivity, and single nucleotide resolution, this approach shows great promise as a next-generation sequencing method. Full article

The poor properties of recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) are considered key constraints hindering the reuse of this waste resource in marine engineering. The CO₂-based accelerated carbonation method, which utilizes the alkali aggregate properties of RCA to achieve CO₂ uptake and sequestration while significantly enhancing its properties, has attracted widespread attention. However, the degree of improvement in the properties of RCA under different initial moisture conditions (IMCs) and aggregate particle sizes (APSs) after CO₂-accelerated carbonation remains unclear. Moreover, the quantitative effect of carbonated recycled coarse aggregate (CRCA), which is obtained from RCA samples with the optimal initial moisture conditions, on the improvement of RCAC under optimal accelerated carbonation modification conditions still needs to be studied in depth. For this investigation, a CO₂-accelerated carbonation experiment was carried out on RCA samples with different IMCs and APSs, and the variations in the properties of RCA with respect to its IMC and APS were assessed. The degree of accelerated carbonation modification of RCA under different IMCs and APSs was quantified, and the optimal initial moisture conditions for enhancing the properties of the RCA were confirmed. By preparing concrete specimens based on the natural coarse aggregate, RCA, and CRCA with the best initial moisture conditions (considering the same concrete–water proportion), the effect of CRCA on the workability, mechanical properties, and durability of the corresponding concrete specimen was determined. The findings of this study can be used to effectively promote the sustainable development of marine science and engineering in the future and contribute to global dual-carbon goals, which are of great practical significance and scientific value. Full article

Monotonic circuits are a class of input–output mode (IOM) asynchronous circuits that are relaxed compared to quasi-delay-insensitive (QDI) IOM asynchronous circuits in terms of signaling the completion of internal processing. Some recent works have demonstrated the superiority of monotonic logic over QDI logic for arithmetic circuits such as adders and multipliers. This paper presents a new monotonic asynchronous two-bit full adder (TFA) that can be duplicated and cascaded to form a ripple-carry adder (RCA). While an RCA is a slow adder with respect to synchronous design, with respect to IOM asynchronous design an RCA is a noteworthy adder since it has perhaps the least reverse latency that is not attainable through other IOM asynchronous adders. Conventionally, an RCA is constructed via a cascade of one-bit full adders (OFAs). An OFA adds two input bits along with any carry input and produces a sum bit and any carry output. On the other hand, a TFA simultaneously adds two pairs of input bits along with any carry input and produces two sum bits and any carry output. Using our proposed monotonic TFA, we realized an RCA to compare its performance with RCAs constructed using different asynchronous OFAs, and RCAs constructed using existing TFAs. We considered the popular delay-insensitive dual-rail scheme for encoding the adder inputs and outputs, and two 4-phase handshake protocols, namely return-to-zero handshaking (R0H) and return-to-one handshaking (R1H) for communication separately. We used a 28 nm CMOS process for implementation and considered a 32-bit addition as an example. Based on the design metrics estimated, the following inferences were derived: (i) compared to the RCA using the state-of-the-art monotonic OFA, the RCA incorporating the proposed TFA achieved a 26% reduction in cycle time for R0H and a 28.5% reduction in cycle time for R1H while dissipating almost the same power; the cycle time governs the data application rate in an IOM asynchronous circuit, and (ii) compared to the RCA comprising an early output QDI TFA, the RCA incorporating the proposed TFA achieved a 22.3% reduction in cycle time for R0H and a 25.4% reduction in cycle time for R1H while dissipating moderately less power. Also, compared to the existing early output QDI TFA, the proposed TFA occupies 40.9% less area for R0H and 42% less area for R1H. Full article

This article introduces a novel asynchronous full adder that operates in an input–output mode (IOM), displaying both monotonicity and an early output characteristic. In a monotonic asynchronous circuit, the intermediate and primary outputs exhibit similar signal transitions as the primary inputs during data and spacer application. The proposed asynchronous full adder ensures monotonicity for processing data and spacer, utilizing dual-rail encoding for inputs and outputs, and corresponds to return-to-zero (RtZ) and return-to-one (RtO) handshaking. The early output feature of the proposed full adder allows the production of sum and carry outputs based on the adder inputs regardless of the carry input when the spacer is supplied. When utilized in a ripple carry adder (RCA) architecture, the proposed full adder achieves significant reductions in design metrics, such as cycle time, area, and power, compared to existing IOM asynchronous full adders. For a 32-bit RCA implementation using a 28 nm CMOS technology, the proposed full adder outperforms an existing state-of-the-art high-speed asynchronous full adder by reducing the cycle time by 10.4% and the area by 15.8% for RtZ handshaking and reduces the cycle time by 9.8% and the area by 15.8% for RtO handshaking without incurring any power penalty. Further, in terms of the power-cycle time product, which serves as a representative measure of energy, the proposed full adder yields an 11.8% reduction for RtZ handshaking and an 11.2% reduction for RtO handshaking. Full article

DNA hydrogels have gained significant attention in recent years as one of the most promising functional polymer materials. To broaden their applications, it is critical to develop efficient methods for the preparation of bulk-scale DNA hydrogels with adjustable mechanical properties. Herein, we introduce a straightforward and efficient molecular design approach to producing physically pure DNA hydrogel and controlling its mechanical properties by adjusting the degree of hydrogen bonding in ultralong single-stranded DNA (ssDNA) precursors, which were generated using a dual rolling circle amplification (RCA)-based strategy. The effect of hydrogen bonding degree on the performance of DNA hydrogels was thoroughly investigated by analyzing the preparation process, morphology, rheology, microstructure, and entrapment efficiency of the hydrogels for Au nanoparticles (AuNPs)–BSA. Our results demonstrate that DNA hydrogels can be formed at 25 °C with simple vortex mixing in less than 10 s. The experimental results also indicate that a higher degree of hydrogen bonding in the precursor DNA resulted in stronger internal interaction forces, a more complex internal network of the hydrogel, a denser hydrogel, improved mechanical properties, and enhanced entrapment efficiency. This study intuitively demonstrates the effect of hydrogen bonding on the preparation and properties of DNA hydrogels. The method and results presented in this study are of great significance for improving the synthesis efficiency and economy of DNA hydrogels, enhancing and adjusting the overall quality and performance of the hydrogel, and expanding the application field of DNA hydrogels. Full article

The RNA contained in exosomes plays a crucial role in information transfer between cells in various life activities. The accurate detection of low-abundance exosome RNA (exRNA) is of great significance for cell function studies and the early diagnosis of diseases. However, their intrinsic properties, such as their short length and high sequence homology, represent great challenges for exRNA detection. In this paper, we developed a dual-signal isothermal amplification method based on rolling circle amplification (RCA) coupled with DNAzyme (RCA–DNAzyme). The sensitive detection of low-abundance exRNA, the specific recognition of their targets and the amplification of the detection signal were studied and explored. By designing padlock probes to specifically bind to the target exRNA, while relying on the ligation reaction to enhance recognition, the precise targeting of exosome RNA was realized. The combination of RCA and DNAzyme could achieve a twice-as-large isothermal amplification of the signal compared to RCA alone. This RCA–DNAzyme assay could sensitively detect a target exRNA at a concentration as low as 527 fM and could effectively distinguish the target from other miRNA sequences. In addition, this technology was successfully proven to be effective for the quantitative detection of miR-21 by spike recovery, providing a new research approach for the accurate detection of low-abundance exRNA and the exploration of unknown exRNA functions. Full article

Pseudomonas aeruginosa is one of the foodborne pathogenic bacteria that greatly threatens human health. An ultrasensitive technology for P. aeruginosa detection is urgently demanded. Herein, based on the mechanism of aptamer-specific recognition, an electrochemical-colorimetric dual-mode ultrasensitive sensing strategy for P. aeruginosa is proposed. The vertices of DNA tetrahedral nanoprobes (DTNPs), that immobilized on the gold electrode were modified with P. aeruginosa aptamers. Furthermore, the G-quadruplex, which was conjugated with a P. aeruginosa aptamer, was synthesized via rolling circle amplification (RCA). Once P. aeruginosa is captured, a hemin/G-quadruplex, which possesses peroxidase-mimicking activity, will separate from the P. aeruginosa aptamer. Then, the exfoliated hemin/G-quadruplexes are collected for oxidation of the 3,3′,5′,5′-tetramethylbenzidine for colorimetric sensing. In the electrochemical mode, the hemin/G-quadruplex that is still bound to the aptamer catalyzes polyaniline (PANI) deposition and leads to a measurable electrochemical signal. The colorimetric and electrochemical channels demonstrated a good forward and reverse linear response for P. aeruginosa within the range of 1–10⁸ CFU mL⁻¹, respectively. Overall, compared with a traditional single-mode sensor for P. aeruginosa, the proposed dual-mode sensor featuring self-calibration not only avoids false positive results but also improves accuracy and sensitivity. Furthermore, the consistency of the electrochemical/colorimetric assay was verified in practical meat samples and showed great potential for applications in bioanalysis. Full article

Monitoring calibration bias in reflectivity (Z_H) in an operational S-band dual-polarization weather radar is the primary requisite for monitoring and prediction (nowcasting) of severe weather and routine weather forecasting using a weather radar network. For this purpose, we combined methods based on self-consistency (SC), ground clutter (GC) monitoring, and intercomparison to monitor the Z_H in real time by complementing the limitations of each method. The absolute calibration bias can be calculated based on the SC between dual-polarimetric observations. Unfortunately, because SC is valid for rain echoes, it is impossible to monitor reflectivity during the non-precipitation period. GC monitoring is an alternative method for monitoring changes in calibration bias regardless of weather conditions. The statistics of GC Z_H near radar depend on the changes in radar system status, such as antenna pointing and calibration bias. The change in GC Z_H relative to the baseline was defined as the relative calibration adjustment (RCA). The calibration bias was estimated from the change in RCA, which was similar to that estimated from the SC. The Z_H in the overlapping volume of adjacent radars was compared to verify the homogeneity of Z_H over the radar network after applying the calibration bias estimated from the SC. The mean bias between two radars was approximately 0.0 dB after correcting calibration bias. We can conclude that the combined method makes it possible to use radar measurements, which are immune to calibration bias, and to diagnose malfunctioning radar systems as soon as possible. Full article

A microRNA (miRNA) detection platform composed of a rolling circle amplification (RCA) system and an allosteric deoxyribozyme system is proposed, which can detect miRNA-21 rapidly and efficiently. Padlock probe hybridization with the target miRNA is achieved through complementary base pairing and the padlock probe forms a closed circular template under the action of ligase; this circular template results in RCA. In the presence of DNA polymerase, RCA proceeds and a long chain with numerous repeating units is formed. In the presence of single-stranded DNA (H1 and H2), multi-component nucleic acid enzymes (MNAzymes) are formed that have the ability to cleave substrates. Finally, substrates containing fluorescent and quenching groups and magnesium ions are added to the system to activate the MNAzyme and the substrate cleavage reaction, thus achieving fluorescence intensity amplification. The RCA–MNAzyme system has dual signal amplification and presents a sensing platform that demonstrates broad prospects in the analysis and detection of nucleic acids. Full article

The prevalence of isolated right coronary artery (RCA) absence ranges from 0.014% to 0.066% in the general population, but its combination with an absent left main (dual ostium left anterior descending [LAD] and super-dominant left circumflex [LCx]) has not been previously described. We report the case of a rare coronary artery anomaly: an absent RCA with LAD and LCx coronary arteries arising separately from the left coronary sinus. A 53-year-old male with recent COVID-19 infection was referred to our service for coronary computed tomography angiography (CCTA) due to the recent onset of atypical chest pain. The RCA was absent, with no vessel leaving the right or non-coronary sinus. The LAD and LCx emerged from the left coronary sinus, with a “double-barrel” appearance. The LAD was unremarkable, with small, non-stenosed calcified plaque. The LCx had a 3 mm diameter, arching downward in the left atrioventricular groove, passing through the crux cordis, continuing into the right atrioventricular groove, and ending as a left acute artery and sinonodal artery. No significant stenosis was found on any of the vessels, ruling out atherosclerotic coronary disease. Full article