Continuous-Time Fixed-Lag Smoothing for LiDAR-Inertial-Camera SLAM

Localization and mapping with heterogeneous multi-sensor fusion have been prevalent in recent years. To adequately fuse multi-modal sensor measurements received at different time instants and different frequencies, we estimate the continuous-time trajectory by fixed-lag smoothing within a factor-graph optimization framework. With the continuous-time formulation, we can query poses at any time instants corresponding to the sensor measurements. To bound the computation complexity of the continuous-time fixed-lag smoother, we maintain temporal and keyframe sliding windows with constant size, and probabilistically marginalize out control points of the trajectory and other states, which allows preserving prior information for future sliding-window optimization. Based on continuous-time fixed-lag smoothing, we design tightly-coupled multi-modal SLAM algorithms with a variety of sensor combinations, like the LiDAR-inertial and LiDAR-inertial-camera SLAM systems, in which online timeoffset calibration is also naturally supported. More importantly, benefiting from the marginalization and our derived analytical Jacobians for optimization, the proposed continuous-time SLAM systems can achieve real-time performance regardless of the high complexity of continuous-time formulation. The proposed multi-modal SLAM systems have been widely evaluated on three public datasets and self-collect datasets. The results demonstrate that the proposed continuous-time SLAM systems can achieve high-accuracy pose estimations and outperform existing state-of-the-art methods. To benefit the research community, we will open source our code at ~\url{https://github.com/APRIL-ZJU/clic}

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

IVIg for apparently autoimmune small-fiber polyneuropathy: first analysis of efficacy and safety

Objectives: Small-fiber polyneuropathy (SFPN) has various underlying causes, including associations with systemic autoimmune conditions. We have proposed a new cause; small-fiber-targeting autoimmune diseases akin to Guillain-Barré and chronic inflammatory demyelinating polyneuropathy (CIDP). There are no treatment studies yet for this ‘apparently autoimmune SFPN’ (aaSFPN), but intravenous immunoglobulin (IVIg), first-line for Guillain-Barré and CIDP, is prescribed off-label for aaSFPN despite very high cost. This project aimed to conduct the first systematic evaluation of IVIg’s effectiveness for aaSFPN. Methods: With IRB approval, we extracted all available paper and electronic medical records of qualifying patients. Inclusion required having objectively confirmed SFPN, autoimmune attribution and other potential causes excluded. IVIg needed to have been dosed at ⩾1 g/kg/4 weeks for ⩾3 months. We chose two primary outcomes – changes in composite autonomic function testing (AFT) reports of SFPN and in ratings of pain severity – to capture objective as well as patient-prioritized outcomes. Results: Among all 55 eligible patients, SFPN had been confirmed by 3/3 nerve biopsies, 62% of skin biopsies, and 89% of composite AFT. Evidence of autoimmunity included 27% of patients having systemic autoimmune disorders, 20% having prior organ-specific autoimmune illnesses and 80% having ⩾1/5 abnormal blood-test markers associated with autoimmunity. A total of 73% had apparent small-fiber-restricted autoimmunity. IVIg treatment duration averaged 28 ± 25 months. The proportion of AFTs interpreted as indicating SFPN dropped from 89% at baseline to 55% (p ⩽ 0.001). Sweat production normalized (p = 0.039) and the other four domains all trended toward improvement. Among patients with pre-treatment pain ⩾3/10, severity averaging 6.3 ± 1.7 dropped to 5.2 ± 2.1 (p = 0.007). Overall, 74% of patients rated themselves ‘improved’ and their neurologists labeled 77% as ‘IVIg responders’; 16% entered remissions that were sustained after IVIg withdrawal. All adverse events were expected; most were typical infusion reactions. The two moderate complications (3.6%) were vein thromboses not requiring discontinuation. The one severe event (1.8%), hemolytic anemia, remitted after IVIg discontinuation. Conclusion: These results provide Class IV, real-world, proof-of-concept evidence suggesting that IVIg is safe and effective for rigorously selected SFPN patients with apparent autoimmune causality. They provide rationale for prospective trials, inform trial design and indirectly support the discovery of small-fiber-targeting autoimmune/inflammatory illnesses

Mechanistic investigation of char growth from lignin monomers during biomass utilisation

Char is formed as a significant product from the pyrolysis of biomass, and it is well reported that lignin is the greatest contributor to the production of char. The structures of lignin chars are well studied in literature; however, an elucidation on the lignin char formation mechanism is lacking and this is essential to achieve precise control of biomass thermal conversion. In this work, the char growth process from β-O-4 linkage derived lignin monomers was investigated using density functional theory (DFT) and validated by slow pyrolysis experiments and Nuclear Magnetic Resonance (NMR) analysis. It was shown that char forms in a two-step process, beginning with the aggregation of two mono-aromatic species to yield tricyclic species, which then participate in further ring forming reactions to yield larger aromatic clusters. The side products generated involve hydrogen, water, methanol, and formaldehyde. Insights from the proposed mechanism are important for guiding future research on char formation during biomass thermochemical conversion processes.This is a manuscript of an article published as Shaw, Alexander, Xiaolei Zhang, Shuya Jia, Juan Fu, Lin Lang, and Robert C. Brown. "Mechanistic investigation of char growth from lignin monomers during biomass utilisation." Fuel Processing Technology 239 (2023): 107556. DOI: 10.1016/j.fuproc.2022.107556. Copyright 2022 Elsevier B.V. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission

Mechanistic investigation of char growth from lignin monomers during biomass utilisation

Char is formed as a significant product from the pyrolysis of biomass, and it is well reported that lignin is the greatest contributor to the production of char. The structures of lignin chars are well studied in literature; however, an elucidation on the lignin char formation mechanism is lacking and this is essential to achieve precise control of biomass thermal conversion. In this work, the char growth process from β-O-4 linkage derived lignin monomers was investigated using density functional theory (DFT) and validated by slow pyrolysis experiments and Nuclear Magnetic Resonance (NMR) analysis. It was shown that char forms in a two-step process, beginning with the aggregation of two mono-aromatic species to yield tricyclic species, which then participate in further ring forming reactions to yield larger aromatic clusters. The side products generated involve hydrogen, water, methanol, and formaldehyde. Insights from the proposed mechanism are important for guiding future research on char formation during biomass thermochemical conversion processes

High-temperature tensile and thermal shock characterization of low-temperature rolled tungsten

A developed tungsten (W) grade was prepared by powder metallurgy technology plus multi-step low-temperature rolling. The relative density, thermal conductivity, microstructure, tensile properties of original and high-temperature annealed states, micro-hardness and transient thermal shock resistance were characterized. The results of tensile test with a strain rate of 2 × 10-4 s−1 show that the ductile–brittle transition temperature (DBTT) of rolled-W in the original and recrystallized state are 150–200 °C and 250–300 °C, respectively. The rolled-W presents high strength and great plasticity simultaneously. For example, the maximum ultimate tensile strength (UTS) below DBTT is as high as ∼ 1189 MPa, and the maximum total elongation (TE) above DBTT reaches 28.9 %. In particular, the TE of recrystallized W achieves an incredible 81.4 % at 500 °C, which is the highest value among all the published literatures so far. The results of transient thermal shock tests indicate that the rolled-W has an outstanding transient thermal shock resistance. It can withstand the thermal bombardment at an absorbed power densities (APD) of 0.33 GW·m−2 without causing any surface damages, and still no cracks are observed as the APD rises to 0.88 GW·m−2. Moreover, the failure mechanism of rolled-W was also studied in details. This work plays an important role in establishing a dependable China Fusion Engineering Test Reactor (CFETR) data-library on a unitary W grade, which can provide an effective reference for the identification of material performance under the high heat flux and subsequent numerical simulation

<b>Investigation of the causal relationship between autoimmune diseases and premature ovarian insufficiency</b>

BackgroundRecent epidemiological studies have reported a correlation between autoimmune diseases (AIDs) and premature ovarian insufficiency (POI). This study aims to explore the causal relationship between AIDs and POI using bidirectional two-sample Mendelian randomization (MR).MethodThe data regarded AIDs from the Genome-wide association studies (GWAS) Catalog and the IEU Open GWAS project. POI was obtained from the FinnGen Study. All data were extracted from European populations. We used bidirectional MR with inverse variance weighting (IVW) as the primary study method, supplemented by weighted median and MR Egger validation analyses.ResultOur study showed that the liability to Systemic lupus erythematosus (SLE) and Myasthenia gravis (MG) affect POI risk. The reverse MR analysis supported the effect of POI on Crohn's disease (CD). The result of the IVW method was supported by the sensitivity MR analysis. The IVW results showed that the odds ratio (OR) value of SLE was 1.13 and MG was 0.83. In the reverse MR, the OR value of CD was 1.22.ConclusionIn summary, our MR study supports a causal relationship between SLE, MG, CD, and POI risk in the European population. We significantly reduce the impact of confounding factors and reverse causation. It provides an innovative methodology for investigating the biological mechanism, early diagnosis, individualized treatment, and prevention.</p