A Study on Graph Optimization Method for GNSS/IMU Integrated Navigation System Based on Virtual Constraints.

In GNSS/IMU integrated navigation systems, factors like satellite occlusion and non-line-of-sight can degrade satellite positioning accuracy, thereby impacting overall navigation system results. To tackle this challenge and leverage historical pseudorange information effectively, this paper proposes a graph optimization-based GNSS/IMU model with virtual constraints. These virtual constraints in the graph model are derived from the satellite's position from the previous time step, the rate of change of pseudoranges, and ephemeris data. This virtual constraint serves as an alternative solution for individual satellites in cases of signal anomalies, thereby ensuring the integrity and continuity of the graph optimization model. Additionally, this paper conducts an analysis of the graph optimization model based on these virtual constraints, comparing it with traditional graph models of GNSS/IMU and SLAM. The marginalization of the graph model involving virtual constraints is analyzed next. The experiment was conducted on a set of real-world data, and the results of the proposed method were compared with tightly coupled Kalman filtering and the original graph optimization method. In instantaneous performance testing, the method maintains an RMSE error within 5% compared with real pseudorange measurement, while in a continuous performance testing scenario with no available GNSS signal, the method shows approximately a 30% improvement in horizontal RMSE accuracy over the traditional graph optimization method during a 10-second period. This demonstrates the method's potential for practical applications.

A Robust and Integrated Visual Odometry Framework Exploiting the Optical Flow and Feature Point Method.

In this paper, we propose a robust and integrated visual odometry framework exploiting the optical flow and feature point method that achieves faster pose estimate and considerable accuracy and robustness during the odometry process. Our method utilizes optical flow tracking to accelerate the feature point matching process. In the odometry, two visual odometry methods are used: global feature point method and local feature point method. When there is good optical flow tracking and enough key points optical flow tracking matching is successful, the local feature point method utilizes prior information from the optical flow to estimate relative pose transformation information. In cases where there is poor optical flow tracking and only a small number of key points successfully match, the feature point method with a filtering mechanism is used for posing estimation. By coupling and correlating the two aforementioned methods, this visual odometry greatly accelerates the computation time for relative pose estimation. It reduces the computation time of relative pose estimation to 40% of that of the ORB_SLAM3 front-end odometry, while ensuring that it is not too different from the ORB_SLAM3 front-end odometry in terms of accuracy and robustness. The effectiveness of this method was validated and analyzed using the EUROC dataset within the ORB_SLAM3 open-source framework. The experimental results serve as supporting evidence for the efficacy of the proposed approach.

Lite-YOLOv8: a more lightweight algorithm for Tubercle Bacilli detection.

Deep learning is a transformative force in the medical field and it has made significant progress as a pivotal alternative to conventional manual testing methods. Detection of Tubercle Bacilli in sputum samples is faced with the problems of complex backgrounds, tiny and numerous objects, and human observation over a long time not only causes eye fatigue, but also greatly increases the error rate of subjective judgement. To solve these problems, we optimize YOLOv8s model and propose a new detection algorithm, Lite-YOLOv8. Firstly, the Lite-C2f module is used to ensure accuracy by significantly reducing the number of parameters. Secondly, a lightweight down-sampling module is introduced to reduce the common feature information loss. Finally, the NWD loss is utilized to mitigate the impact of small object positional bias on the IoU. On the public Tubercle Bacilli datasets, the mean average precision of 86.3% was achieved, with an improvement of 2.2%, 1.5%, and 2.8% over the baseline model (YOLOv8s) in terms of mAP0.5, precision, and recall, respectively. In addition, the parameters reduced from 11.2 to 5.1 M, and the number of GFLOPs from 28.8 to 13.8. Our model is not only more lightweight, but also more accurate, thus it can be easily deployed on computing-poor medical devices to provide greater convenience to doctors.

Meta-Analysis of Simultaneous versus Staged Decompression of Stenotic Regions in Patients with Tandem Spinal Stenosis.

BACKGROUND: Tandem spinal stenosis (TSS) refers to simultaneous spinal canal stenosis of noncontiguous regions. There is no consensus in the surgical strategies for patients with symptomatic TSS because of the confusing clinical manifestations. This meta-analysis aimed to compare the outcomes of 1-stage and 2-stage decompression of all stenotic regions (cervical and lumbar/thoracic segments) in patients with TSS. METHODS: A systematic review was conducted, and a comprehensive literature search with the Japanese Orthopedic Association score, was carried out using MEDLINE, Web of Science, and PubMed databases from inception to September 13, 2022. Observational studies reporting the outcomes after 1-stage or 2-stage decompression of all symptomatic regions were included. Possible heterogeneity among studies was assessed by the Higgins I2 test, and heterogeneity was statistically investigated using the Q statistic. RESULTS: Thirteen retrospective observational studies were included in this meta-analysis. Meta-analysis showed that there was no significant difference in the Japanese Orthopedic Association score improvement in patients with TSS involving either the cervical-thoracic or cervical-lumbar segments. Regarding the surgical parameters and complications, 1-stage decompression showed comparable operation time, blood loss, and major complications to 2-stage decompression in patients with cervical and lumbar TSS. In patients with cervical and thoracic TSS, 1-stage decompression had significant advantages compared with 2-stage decompression in operation time, blood loss, and major complications. CONCLUSIONS: For patients with cervical and lumbar TSS, 2-stage decompression showed slight advantages in clinical outcome without exposing patients to unnecessary surgical risks. For patients with cervical and thoracic TSS, 1-stage decompression showed comparable clinical outcome, although with better operative parameters and lower complication rate than in simultaneous decompression.

A novel surgical technique for cervical laminoplasty in patients with multilevel cervical spondylotic myelopathy: A case report and literature review.

Cervical laminoplasty is a posterior-based surgical decompression technique for the treatment of multilevel cervical spondylotic myelopathy (CSM) that may improve the preservation of cervical mobility, spinal canal structure, and natural lordosis. Although this procedure is considered to be comparatively safe, with fewer complications than those seen with laminectomy, several postoperative problems have been noted, including axial neck pain, C5 nerve palsy, and failed resolution of radiculopathy. Hence, various modifications have been made to improve the safety and effectiveness of this technique. Here, we report the case of a 74-year-old man with multilevel CSM who underwent posterior cervical laminoplasty in the C3-C7 segments using a novel surgical technique, termed alternating-side cervical laminoplasty. Preoperative and postoperative assessments, including visual analog scale, modified Japanese Orthopaedic Association, neck disability index scores, and imaging data, were collected and analyzed. The results of a 5-year follow-up indicated that the patient recovered well, with no development of axial neck pain. This is the first report of this modified open-door laminoplasty, which we propose may be a better surgical option for preventing postoperative axial neck pain in patients with multilevel CSM. Additionally, opening the laminae on the alternating sides during laminoplasty could provide a flexible approach to complete decompression on different radiculopathy sides.

Genome-Wide Association Study of the Genetic Basis of Effective Tiller Number in Rice.

BACKGROUND: Effective tiller number (ETN) has a pivotal role in determination of rice (Oryza sativa L.) grain yield. ETN is a complex quantitative trait regulated by both genetic and environmental factors. Despite multiple tillering-related genes have been cloned previously, few of them have been utilized in practical breeding programs. RESULTS: In this study, we conducted a genome-wide association study (GWAS) for ETN using a panel of 490 rice accessions derived from the 3 K rice genomes project. Thirty eight ETN-associated QTLs were identified, interestingly, four of which colocalized with the OsAAP1, DWL2, NAL1, and OsWRKY74 gene previously reported to be involved in rice tillering regulation. Haplotype (Hap) analysis revealed that Hap5 of OsAAP1, Hap3 and 6 of DWL2, Hap2 of NAL1, and Hap3 and 4 of OsWRKY74 are favorable alleles for ETN. Pyramiding favorable alleles of all these four genes had more enhancement in ETN than accessions harboring the favorable allele of only one gene. Moreover, we identified 25 novel candidate genes which might also affect ETN, and the positive association between expression levels of the OsPILS6b gene and ETN was validated by RT-qPCR. Furthermore, transcriptome analysis on data released on public database revealed that most ETN-associated genes showed a relatively high expression from 21 days after transplanting (DAT) to 49 DAT and decreased since then. This unique expression pattern of ETN-associated genes may contribute to the transition from vegetative to reproductive growth of tillers. CONCLUSIONS: Our results revealed that GWAS is a feasible way to mine ETN-associated genes. The candidate genes and favorable alleles identified in this study have the potential application value in rice molecular breeding for high ETN and grain yield.

Using scalp EEG and intracranial EEG signals for predicting epileptic seizures: Review of available methodologies.

Patients suffering from epileptic seizures are usually treated with medication and/or surgical procedures. However, in more than 30% of cases, medication or surgery does not effectively control seizure activity. A method that predicts the onset of a seizure before it occurs may prove useful as patients might be alerted to make themselves safe or seizures could be prevented with therapeutic interventions just before they occur. Abnormal neuronal activity, the preictal state, starts a few minutes before the onset of a seizure. In recent years, different methods have been proposed to predict the start of the preictal state. These studies follow some common steps, including recording of EEG signals, preprocessing, feature extraction, classification, and postprocessing. However, online prediction of epileptic seizures remains a challenge as all these steps need further refinement to achieve high sensitivity and low false positive rate. In this paper, we present a comparison of state-of-the-art methods used to predict seizures using both scalp and intracranial EEG signals and suggest improvements to existing methods.

Mutations in the MIT3 gene encoding a caroteniod isomerase lead to increased tiller number in rice.

Carotenoids not only play important roles in light harvesting and photoprotection against excess light, but also serve as precursors for apocaroteniod hormones such as abscisic acid (ABA) and strigolactones (SLs). Although light- and ABA-associated phenotypes of the carotenoid biosynthesis mutants such as albino, leaf variegation and preharvest sprouting have been studied extensively, the SLs-related branching phenotype is rarely explored. Here we characterized four allelic rice mutants named mit3, which exhibited moderately increased tiller number, semi-dwarfism and leaf variegation. Map-based cloning revealed that MIT3 encodes a carotenoid isomerase (CRTISO), the key enzyme catalyzing the conversion from prolycopene to all-trans-lycopene in carotenoid biosynthesis. Prolycopene was accumulated while all-trans-lycopene was barely detectable in the dark-grown mit3 seedlings. Accordingly, content of lutein and ß-carotene, the two most abundant carotenoids, was significantly reduced. Furthermore, content of epi-5DS, a native SL, was significantly reduced in mit3. Exogenously applied GR24, a synthetic SL, could rescue the tillering phenotype of mit3. Double mutant analysis of mit3 with the SLs biosynthesis mutant d17 revealed that MIT3 controls tiller development upstream of the SLs biosynthesis pathway. Our results reveal that the tillering phenotype of mit3 is due to SL deficiency and directly link carotenoid deficiency with SL-regulated rice tillering.

Inhibition of NF-κB signaling pathway induces apoptosis and suppresses proliferation and angiogenesis of human fibroblast-like synovial cells in rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is the most common inflammatory arthritis and is a major cause of disability. The nuclear factor-kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway has been reported to be involved in the pathogenesis of RA with unclear mechanisms. Therefore, this study aims to explore the effect of NF-κB pathway on proliferation, apoptosis, and angiogenesis of human fibroblast-like synovial cells (HFLS) in RA. METHODS: Normal HFLS and RA-HFLS were selected as the normal and control groups, respectively. RA-HFLS were treated by BAY11-7082 (an inhibitor of NF-κB) in different concentrations, namely 2.5 µmol/L BAY11-7082, 5 µmol/LBAY11-7082 and 10 µmol/L BAY11-7082. MTT assay was employed to detect cell proliferation. Cell apoptosis was determined by flow cytometry at 24, 48, and 72 hours after culture. Western blot analysis was employed to detect the expressions of NF-κB, angiogenesis-related factors (VEGF, Ang1, and Ang2). RESULTS: Initially, we found that BAY11-7082 inhibited NF-κB expression in a concentration-dependent manner. According to the findings of MTT assay and flow cytometry, we understood that RA-HFLS treated by BAY11-7082 (an inhibitor of NF-κB), the inhibition of NF-κB pathway, suppressed RA-HFLS proliferation and induced RA-HFLS apoptosis in a concentration and time-dependent manner. Furthermore, RA-HFLS treated by BAY11-7082 presented decreased VEGF, Ang1 and Ang2 expressions in a concentration-dependent manner. CONCLUSION: The study concluded that inhibition of NF-κB pathway induced cell apoptosis and suppressed proliferation and angiogenesis of RA-HFLS, which could serve as a novel target in the treatment of RA.

The neuroprotective effect of apelin-13 in a mouse model of intracerebral hemorrhage.

Adipocytokine apelin-13 is a peptide which could reportedly protect the brain against ischemic reperfusion injury and traumatic brain injury (TBI). Whether apelin-13 has any roles to play in intracerebral hemorrhage (ICH) has not been clarified. We aimed to investigate the roles of apelin-13 in ICH and effects on ICH-induced apoptosis. Firstly, CD-1 mice were subjected to infusion of Type IV collagenase (to induce ICH) or saline (for shams) into the left striatum. ICH animals received intracerebroventricular administration of vehicle, apelin-13 (50µg dissolved in 5µl saline) immediately after ICH. The motor function and the cerebral water content (CWC) as well as blood brain barrier (BBB) disruption were measured, coupled with determination of ICH-induced neural cell death by Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL). The apoptosis-associated proteins caspase-3 and Bcl-2 as well as the brain edema-associated proteins aquaporin-4 (AQP4) and MMP-9 were all assessed with western blotting. The results showed that apelin-13 decreased CWC and reduced Evans blue leakage into injured hemispheres, with the motor function significantly improved. Additionally, apelin-13 also acutely decreased the number of ICH-induced TUNEL-positive (TUNEL(+)) cells at 48h after ICH. The expressions of AQP4, MMP-9, caspse-3 and Bcl-2 were all downregulated by apelin-13 at 24h and 48h after ICH. All these results revealed that apelin-13 attenuated brain edema and reduced cellular death by suppressing apoptosis after ICH in mice.

Apelin-13 as a novel target for intervention in secondary injury after traumatic brain injury.

The adipocytokine, apelin-13, is an abundantly expressed peptide in the nervous system. Apelin-13 protects the brain against ischemia/reperfusion injury and attenuates traumatic brain injury by suppressing autophagy. However, secondary apelin-13 effects on traumatic brain injury-induced neural cell death and blood-brain barrier integrity are still not clear. Here, we found that apelin-13 significantly decreases cerebral water content, mitigates blood-brain barrier destruction, reduces aquaporin-4 expression, diminishes caspase-3 and Bax expression in the cerebral cortex and hippocampus, and reduces apoptosis. These results show that apelin-13 attenuates secondary injury after traumatic brain injury and exerts a neuroprotective effect.