STGIC: A graph and image convolution-based method for spatial transcriptomic clustering.

Spatial transcriptomic (ST) clustering employs spatial and transcription information to group spots spatially coherent and transcriptionally similar together into the same spatial domain. Graph convolution network (GCN) and graph attention network (GAT), fed with spatial coordinates derived adjacency and transcription profile derived feature matrix are often used to solve the problem. Our proposed method STGIC (spatial transcriptomic clustering with graph and image convolution) is designed for techniques with regular lattices on chips. It utilizes an adaptive graph convolution (AGC) to get high quality pseudo-labels and then resorts to dilated convolution framework (DCF) for virtual image converted from gene expression information and spatial coordinates of spots. The dilation rates and kernel sizes are set appropriately and updating of weight values in the kernels is made to be subject to the spatial distance from the position of corresponding elements to kernel centers so that feature extraction of each spot is better guided by spatial distance to neighbor spots. Self-supervision realized by Kullback-Leibler (KL) divergence, spatial continuity loss and cross entropy calculated among spots with high confidence pseudo-labels make up the training objective of DCF. STGIC attains state-of-the-art (SOTA) clustering performance on the benchmark dataset of 10x Visium human dorsolateral prefrontal cortex (DLPFC). Besides, it's capable of depicting fine structures of other tissues from other species as well as guiding the identification of marker genes. Also, STGIC is expandable to Stereo-seq data with high spatial resolution.

Accurate 3D LiDAR SLAM System Based on Hash Multi-Scale Map and Bidirectional Matching Algorithm.

Simultaneous localization and mapping (SLAM) is a hot research area that is widely required in many robotics applications. In SLAM technology, it is essential to explore an accurate and efficient map model to represent the environment and develop the corresponding data association methods needed to achieve reliable matching from measurements to maps. These two key elements impact the working stability of the SLAM system, especially in complex scenarios. However, previous literature has not fully addressed the problems of efficient mapping and accurate data association. In this article, we propose a novel hash multi-scale (H-MS) map to ensure query efficiency with accurate modeling. In the proposed map, the inserted map point will simultaneously participate in modeling voxels of different scales in a voxel group, enabling the map to represent objects of different scales in the environment effectively. Meanwhile, the root node of the voxel group is saved to a hash table for efficient access. Secondly, considering the one-to-many (1 ×103 order of magnitude) high computational data association problem caused by maintaining multi-scale voxel landmarks simultaneously in the H-MS map, we further propose a bidirectional matching algorithm (MSBM). This algorithm utilizes forward-reverse-forward projection to balance the efficiency and accuracy problem. The proposed H-MS map and MSBM algorithm are integrated into a completed LiDAR SLAM (HMS-SLAM) system. Finally, we validated the proposed map model, matching algorithm, and integrated system on the public KITTI dataset. The experimental results show that, compared with the ikd tree map, the H-MS map model has higher insertion and deletion efficiency, both having O(1) time complexity. The computational efficiency and accuracy of the MSBM algorithm are better than that of the small-scale priority matching algorithm, and the computing speed of the MSBM achieves 49 ms/time under a single CPU thread. In addition, the HMS-SLAM system built in this article has also reached excellent performance in terms of mapping accuracy and memory usage.

Chemistry and biosynthesis of bacterial polycyclic xanthone natural products.

Covering: up to the end of 2021Bacterial polycyclic xanthone natural products (BPXNPs) are a growing family of natural xanthones featuring a pentangular architecture with various modifications to the tricyclic xanthone chromophore. Their structural diversities and various activities have fueled biosynthetic and chemical synthetic studies. Moreover, their more potent activities than the clinically used drugs make them potential candidates for the treatment of diseases. Future unraveling of structure activity relationships (SARs) will provide new options for the (bio)-synthesis of drug analogues with higher activities. This review summarizes the isolation, structural elucidation and biological activities and more importantly, the recent strategies for the microbial biosynthesis and chemical synthesis of BPXNPs. Regarding their biosynthesis, we discuss the recent progress in enzymes that synthesize tricyclic xanthone, the protein candidates for structural moieties (methylene dioxygen bridge and nitrogen heterocycle), tailoring enzymes for methylation and halogenation. The chemical synthesis part summarizes the recent methodology for the division synthesis and coupling construction of achiral molecular skeletons. Ultimately, perspectives on the biosynthetic study of BPXNPs are discussed.

The prediction effects of thyroid function in the severity of Guillain-Barré syndrome.

BACKGROUND: Guillain-Barré syndrome (GBS), an acquired immune-mediated inflammatory disorder affecting the peripheral nervous system (PNS), is usually complicated with autoimmune diseases including thyroid diseases. Herein, we explored roles of thyroid function and thyroid autoantibodies in the disease severity and its short-term prognosis of GBS. In addition, we further investigated the predictive value of thyroid function for GBS respiratory insufficiency. MATERIALS AND METHODS: We retrospectively analyzed the clinical data of 219 GBS patients. According to the thyroid function, the enrolled subjects were divided into 2 groups, that is, patients with abnormal thyroid function (case group) and those with normal thyroid function (control group). The clinical characteristics, disease severity, and short-term prognosis of the patients in 2 groups were compared. In addition, we also divided the 219 GBS patients into mechanical ventilation (MV) group and non-MV group according to whether MV was performed within 1 week after admission. The clinical characteristics, disease severity, short-term prognosis, Erasmus GBS respiratory insufficiency score (EGRIS), and the thyroid function were compared in the two groups. RESULTS: We found that GBS patients with abnormal thyroid function had longer duration of hospitalization, higher frequency of cranial nerve damage, and higher incidence of weakened tendon reflexes. Medical Research Council (MRC) scores on admission, at nadir, and at discharge were lower, and Hughes Functional Grading Scale (HFGS) scores on admission and at discharge were higher in GBS patients with abnormal thyroid function group. More patients in the abnormal thyroid function group had myelin, axonal, and myelin-axonal injuries. In the MV group, the time from onset to admission, MRC scores on admission, and the levels of free triiodothyronine (FT3) were lower; the levels of thyroglobulin antibody (TgAb) and EGRIS were significantly higher than those in the non-MV group. The combination of EGRIS and FT3 serum levels to predict GBS patients with MV, the area under the curve (AUC) was 0.905 (95% CI: 0.861 to 0.948, P < 0.05), sensitivity was 88.9%, and specificity was 84.7%. CONCLUSION: Our results suggest that the serum FT3 levels are negatively correlated with disease severity; the serum FT3 might be a biomarker for the incidence and severity of GBS. Both EGRIS and serum FT3 have a predictive value for the occurrence of acute respiratory insufficiency in GBS patients, and the combination of these two indicators can more accurately predict the risk of acute respiratory insufficiency in GBS patients.

Quantitative mapping of DNA phosphorothioatome reveals phosphorothioate heterogeneity of low modification frequency.

Phosphorothioate (PT) modifications of the DNA backbone, widespread in prokaryotes, are first identified in bacterial enteropathogens Escherichia coli B7A more than a decade ago. However, methods for high resolution mapping of PT modification level are still lacking. Here, we developed the PT-IC-seq technique, based on iodine-induced selective cleavage at PT sites and high-throughput next generation sequencing, as a mean to quantitatively characterizing the genomic landscape of PT modifications. Using PT-IC-seq we foud that most PT sites are partially modified at a lower PT frequency (< 5%) in E. coli B7A and Salmonella enterica serovar Cerro 87, and both show a heterogeneity pattern of PT modification similar to those of the typical methylation modification. Combining the iodine-induced cleavage and absolute quantification by droplet digital PCR, we developed the PT-IC-ddPCR technique to further measure the PT modification level. Consistent with the PT-IC-seq measurements, PT-IC-ddPCR analysis confirmed the lower PT frequency in E. coli B7A. Our study has demonstrated the heterogeneity of PT modification in the bacterial population and we also established general tools for rigorous mapping and characterization of PT modification events at whole genome level. We describe to our knowledge the first genome-wide quantitative characterization of PT landscape and provides appropriate strategies for further functional studies of PT modification.

Correction to: Genome-wide identifcation and characterization of the C2 domain family in Sorghum bicolor (L.) and expression profles in response to saline-alkali stress.

[This corrects the article DOI: 10.1007/s12298-022-01222-3.].

Genome-wide identification and characterization of the C2 domain family in Sorghum bicolor (L.) and expression profiles in response to saline-alkali stress.

The C2 domain family proteins in plants has been recently shown to be involved in the response to abiotic stress such as salt and drought stress. However, less information on C2 domain family members has been reported in Sorghum bicolor (L.), which is a tolerant cereal crop. To elaborate the mechanism of C2 domain family members in response to abiotic stress, bioinformatic methods were used to analyze this family. The results indicated that 69 C2 domain genes belonging to 5 different groups were first identified within the sorghum genome, and each group possessed various gene structures and conserved functional domains. Second, those C2 family genes were localized on 10 chromosomes 3 tandem repeat genes and 1 pair of repeat gene fragments were detected. The family members further presented a variety of stress responsive cis-elements. Third, in addition to being the major integral component of the membrane, sorghum C2 domain family proteins mainly played roles in response to abiotic and biotic stress with their organic transport and catalytic activity by specific location in the cell on the basis of gene ontology analysis. C2 family genes were differentially expressed in root, shoot or leaf, and shown different expression profiling after saline-alkali stress, which indicated that C2 family members played an important role in response to saline-alkali stress based on the transcription profiles of RNA-seq data and expression analysis by quantitative real-time polymerase chain reaction. Besides, most C2 family members were mainly located in cytoplasmi and nucleus. Weighted gene co-expression network analysis revealed three modules (turquoise, dark magenta and pink) that were associated with stress resistance, respectively. Therefore, the present research provides comprehensive information for further analysis of the molecular function of C2 domain family genes in sorghum. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-022-01222-3.

Acyltransferase AniI, a Tailoring Enzyme with Broad Substrate Tolerance for High-Level Production of Anisomycin.

Anisomycin (compound 1), a pyrrolidine antibiotic, exhibits diverse biological and pharmacologic activities. The biosynthetic gene cluster of compound 1 has been identified previously, and the multistep assembly of the core benzylpyrrolidine scaffold was characterized. However, enzymatic modifications, such as acylation, involved in compound 1 biosynthesis are unknown. In this study, the genetic manipulation of aniI proved that it encoded an indispensable acetyltransferase for compound 1 biosynthesis. Bioinformatics analysis suggested AniI as a member of maltose (MAT) and galactoside O-acetyltransferases (GAT) with C-terminal left-handed parallel beta-helix (LbH) subdomain, which were referred to as LbH-MAT-GAT sugar O-acetyltransferases. However, the biochemical assay identified that its target site was the hydroxyl group of the pyrrolidine ring. AniI was found to be tolerant of acyl donors with different chain lengths for the biosynthesis of compound 1 and derivatives 12 and 13 with butyryl and isovaleryl groups, respectively. Meanwhile, it showed comparable activity toward biosynthetic intermediates and synthesized analogues, suggesting promiscuity to the pyrrolidine ring structure of compound 1. These data may inspire new viable synthetic routes for the construction of more complex pyrrolidine ring scaffolds in compound 1. Finally, the overexpression of aniI under the control of strong promoters contributed to the higher productivities of compound 1 and its analogues. These findings reported here not only improve the understanding of anisomycin biosynthesis but also expand the substrate scope of O-acetyltransferase working on the pyrrolidine ring and pave the way for future metabolic engineering construction of high-yield strains. IMPORTANCE Acylation is an important tailoring reaction during natural product biosynthesis. Acylation could increase the structural diversity and affect the chemical stability, volatility, biological activity, and even the cellular localization of specialized compounds. Many acetyltransferases have been reported in natural product biosynthesis. The typical example of the LbH-MAT-GAT sugar O-acetyltransferase subfamily was reported to catalyze the coenzyme A (CoA)-dependent acetylation of the 6-hydroxyl group of sugars. However, no protein of this family has been characterized to acetylate a nonsugar secondary metabolic product. Here, AniI was found to catalyze the acylation of the hydroxyl group of the pyrrolidine ring and be tolerant of diverse acyl donors and acceptors, which made the biosynthesis more efficient and exclusive for biosynthesis of compound 1 and its derivatives. Moreover, the overexpression of aniI serves as a successful example of genetic manipulation of a modification gene for the high production of final products and might set the stage for future metabolic engineering.

Microwave ablation versus parathyroidectomy for severe secondary hyperparathyroidism in patients on hemodialysis: a retrospective multicenter study.

BACKGROUND: Microwave ablation is effective for severe secondary hyperparathyroidism, but the difference in efficacy between microwave ablation and parathyroidectomy remains unclear. In this multicenter retrospective cohort study, we compared the long-term clinical efficacy of microwave ablation and parathyroidectomy for severe secondary hyperparathyroidism undergoing hemodialysis. MATERIALS AND METHODS: The patients were divided into microwave ablation and parathyroidectomy groups. The primary endpoint was the proportion of patients with intact parathyroid hormone (iPTH) concentrations within the target range (100-600 pg/mL) during the efficacy assessment phase. The secondary endpoints were (i) differences in iPTH concentrations over time between the two groups, and (ii) decreases in iPTH concentrations over time in the two groups. RESULTS: Microwave ablation was performed in 47/92 patients and parathyroidectomy in 45/92. Primary endpoint: iPTH concentrations within the target range were achieved during the efficacy assessment phase in 26/47 patients (55.3%) and in 14/45 (31.1%) patients in the microwave ablation and parathyroidectomy groups, respectively (p = .02). Secondary endpoints: (i) Mean iPTH concentrations during the efficacy assessment phase were significantly higher in the microwave ablation versus parathyroidectomy groups (649 ± 519 pg/mL versus 136 ± 228 pg/mL, respectively; p < .01). (ii) Mean decrease in iPTH concentration from baseline was 725 ± 605 pg/mL versus 1369 ± 478 pg/mL in the MWA versus parathyroidectomy groups, respectively (p < .01). CONCLUSIONS: Ultrasound-guided percutaneous microwave ablation provides higher iPTH target-achieving rates than parathyroidectomy in patients with severe secondary hyperparathyroidism undergoing hemodialysis.

Flavin Adenine Dinucleotide-Dependent Halogenase XanH and Engineering of Multifunctional Fusion Halogenases.

Xantholipin (compound 1), a polycyclic xanthone antibiotic, exhibited strong antibacterial activities and showed potent cytotoxicity. The biosynthetic gene cluster of compound 1 has been identified in our previous work, and the construction of xanthone nucleus has been well demonstrated. However, limited information of the halogenation involved in compound 1 biosynthesis is available. In this study, based on the genetic manipulation and biochemical assay, we characterized XanH as an indispensable flavin adenine dinucleotide (FAD)-dependent halogenase (FDH) for the biosynthesis of compound 1. XanH was found to be a bifunctional protein capable of flavin reduction and chlorination and exclusively used the NADH. However, the reduced flavin could not be fully and effectively utilized, and the presence of an extra flavin reductase (FDR) and chemical-reducing agent could promote the halogenation. XanH accepted its natural free-standing substrate with angular fused polycyclic aromatic systems. Meanwhile, it exhibited moderate halogenation activity and possessed high substrate specificity. The requirement of extra FDR for higher halogenation activity is tedious for future engineering. To facilitate efforts in engineering XanH derivative proteins, we constructed the self-sufficient FDR-XanH fusion proteins. The fusion protein E1 with comparable activities to that of XanH could be used as a good alternative for future protein engineering. Taken together, these findings reported here not only improve the understanding of polycyclic xanthones biosynthesis but also expand the substrate scope of FDH and pave the way for future engineering of biocatalysts for new active substance synthesis.IMPORTANCE Halogenation is important in medicinal chemistry and plays an essential role in the biosynthesis of active secondary metabolites. Halogenases have evolved to catalyze reactions with high efficiency and selectivity, and engineering efforts have been made to engage the selective reactivity in natural product biosynthesis. The enzymatic halogenations are an environmentally friendly approach with high regio- and stereoselectivity, which make it a potential complement to organic synthesis. FDHs constitute one of the most extensively elucidated class of halogenases; however, the inventory awaits to be expanded for biotechnology applications and for the generation of halogenated natural product analogues. In this study, XanH was found to reduce flavin and halogenated the freely diffusing natural substrate with an angular fused hexacyclic scaffold, findings which were different from those for the exclusively studied FDHs. Moreover, the FDR-XanH fusion protein E1 with comparable reactivity to that of XanH serves as a successful example of genetic fusions and sets an important stage for future protein engineering.

Parallelized fiber Michelson interferometers with advanced curvature sensitivity plus abated temperature crosstalk.

In this Letter, we proposed a super sensitive optic-fiber curvature sensor with ultra-low temperature crosstalk based on Vernier effect and achieved it experimentally. This sensor composes a pair of parallelized 2CFMIs (2-core-fiber Michelson interferometers) in similar lengths, both of which are involved sensing, but there is a rotation angle between their cross-sections. When the rotation angle approaches 180°, the magnification factor for curvature sensitivity is doubled compared with conventional Vernier effect, while for temperature it is always 1. Therefore, advanced curvature sensitivity and abated temperature crosstalk can be realized simultaneously when demodulating Vernier envelops. The experiment results indicate that the curvature sensitivity of this sensor reached 214.533nm/m-1, and temperature crosstalk was as low as 0.000276m-1/∘C. The fabrication process is extremely flexible and repeatable, and the magnification factor of Vernier effect could be controlled conveniently.

Ruthenium Nanoparticles Anchored on Graphene Hollow Nanospheres Superior to Platinum for the Hydrogen Evolution Reaction in Alkaline Media.

The design and construction of highly efficient and stable Pt-free catalysts for the electrocatalytic hydrogen evolution reaction (HER) in alkaline media is extremely desirable. Herein, a novel hybrid of ruthenium (Ru) nanoparticles anchored on graphene hollow nanospheres (GHSs) is synthesized by a template-assisted strategy. The combination of ultrafine Ru nanoparticles and hollow spherical support endows the resultant Ru/GHSs an extraordinary catalytic performance with a low overpotential of 24.4 mV at a current density of 10 mA cm-2, a small Tafel slope of 34.8 mV dec-1, as well as long-term stability in 1.0 M KOH solution, which is, to our knowledge, superior to commercial 20% Pt-C catalyst and most of the state-of-the-art HER electrocatalysts reported. Remarkably, this work provides a new route for the development of other metal-based HER electrocatalysts for energy-related applications.

Temperature self-compensation strain sensor based on cascaded concave-lens-like long-period fiber gratings.

A robust, novel, to the best of our knowledge, fiber Mach-Zehnder interferometer strain sensor is designed and experimentally implemented. The sensor consists of two concave-lens-like long-period fiber gratings and is engraved by the high frequency ${{\rm CO}_2}$CO2 laser. The concave-lens-like grids can excite higher-order cladding modes to interfere with the fundamental mode, which increases the light-material contact. The excellent interference spectra are obtained and analyzed theoretically. The experimental results show that the strain sensitivity of the sensor can reach 0.011 dB/µ$\unicode{x03B5}$ε in the range of 0-2160 µ$\unicode{x03B5}$ε. The resolution of the sensor is up to 0.91 µ$\unicode{x03B5}$ε. Moreover, the temperature crosstalk can be self-compensated by monitoring a pair of split interfering dips. These outstanding characteristics make it very suitable as a candidate for strain measurement.

Biosynthesis of the pyrrolidine protein synthesis inhibitor anisomycin involves novel gene ensemble and cryptic biosynthetic steps.

The protein synthesis inhibitor anisomycin features a unique benzylpyrrolidine system and exhibits diverse biological and pharmacologic activities. Its biosynthetic origin has remained obscure for more than 60 y, however. Here we report the identification of the biosynthetic gene cluster (BGC) of anisomycin in Streptomyces hygrospinosus var. beijingensis by a bioactivity-guided high-throughput screening method. Using a combination of bioinformatic analysis, reverse genetics, chemical analysis, and in vitro biochemical assays, we have identified a core four-gene ensemble responsible for the synthesis of the pyrrolidine system in anisomycin: aniQ, encoding a aminotransferase that catalyzes an initial deamination and a later reamination steps; aniP, encoding a transketolase implicated to bring together an glycolysis intermediate with 4-hydroxyphenylpyruvic acid to form the anisomycin molecular backbone; aniO, encoding a glycosyltransferase that catalyzes a cryptic glycosylation crucial for downstream enzyme processing; and aniN, encoding a bifunctional dehydrogenase that mediates multistep pyrrolidine formation. The results reveal a BGC for pyrrolidine alkaloid biosynthesis that is distinct from known bacterial alkaloid pathways, and provide the signature sequences that will facilitate the discovery of BGCs encoding novel pyrrolidine alkaloids in bacterial genomes. The biosynthetic insights from this study further set the foundation for biosynthetic engineering of pyrrolidine antibiotics.

CtcS, a MarR family regulator, regulates chlortetracycline biosynthesis.

BACKGROUND: Chlortetracycline (CTC) is one of the commercially important tetracyclines (TCs) family product and is mainly produced by Streptomyces. CTC is still in a great demand due to its broad-spectrum activity against pathogens. Engineering transcriptional control allows the cell to allocate its valuable resources towards protein production and provides an important method for the build-up of desired metabolites. Despite extensive efforts concerning transcriptional regulation for increasing the productivities of TCs, the regulatory mechanisms of the CTC biosynthesis remain poorly understood. RESULTS: In this study, the possible regulatory function of CtcS, a potential member of MarR (multiple antibiotic resistance regulator) family of transcriptional regulators in S. aureofaciens F3, was demonstrated. Knockdown of ctcS altered the transcription of several biosynthesis-related genes and reduced the production of tetracycline (TC) and CTC, without obvious effect on morphological differentiation and cell growth. Especially, CtcS directly repressed the transcription of the adjacent divergent gene ctcR (which encodes a putative TC resistance efflux protein). A CtcS-binding site was identified within the promoter region of ctcR by DNase I footprinting and an inverted repeat (5'-CTTGTC-3') composed of two 6-nt half sites in the protected region was found. Moreover, both CTC and TC could attenuate the binding activity of CtcS with target DNA. CONCLUSION: ctcS regulated the production of TC and CTC in S. aureofaciens F3 and the overexpression of it could be used as a simple approach for the construction of engineering strain with higher productivity. Meanwhile, CtcS was characterized as a TC- and CTC-responsive MarR family regulator. This study provides a previously unrecognized function of CtcS and will benefit the research on the regulatory machinery of the MarR family regulators.

Torsion bidirectional sensor based on tilted-arc long-period fiber grating.

Fiber torsion sensor has been researched for many years due to its various structure and sensitive response. In order to distinguish the torsion direction, fiber sensor still faces some difficult problems, including complex fabricating condition, special fiber structure and limited sensitivity. In this paper, a novel long-period fiber grating (LPFG) formed by tilted-arc grids is designed and fabricated in the normal simple-mode fiber, showing small size and high sensitivity. The asymmetrical tilted-arc grid structure can induce considerable chirality into the tilted-arc LPFG to enable it to distinguish torsion direction, which doesn't need any equipment to rotate or twist the fiber in the fabrication process. Theoretical analysis indicates that the structure can respond opposite wavelength shifting to the opposite torsion directions, and the torsion sensitivity is related to both the radius and tilted angle of grid. A series of tilted-arc LPFGs are fabricated with CO2-laser scanning and tested in torsion experiment, all of whom can distinguish bidirectional torsion. The maximum sensitivity value can reach 0.514 nm/(rad·m-1), which is higher than many normal tilted LPFGs and twisted fiber structures. The novel LPFG has the potential to be applied in directional torsion field due to its direction-distinguishing ability, high sensitivity and simple fabrication.

Protruding-shaped SiO2-microtip: from fabrication innovation to microphotonic device construction.

In this Letter, we first proposed a new technology to prepare protruding-shaped SiO2-microtips (PSSMs): transient spinning technology (TST). By designing the operation steps and controlling the discharge parameters of a fiber splicing machine (Furukawa S178a), the protruding-shaped SiO2-microtips with different structural parameters can be fabricated simply, quickly, and efficiently. Two kinds of microtip photonic devices were designed: (1) a high-sensitivity gas refractive index Mach-Zehnder interferometer sensor based on the coned microtip and (2) an efficient LP11-mode selective exciter based on the lensed microtip. Furthermore, the PSSMs have more potential applications, such as optical fiber tweezers, optical fiber Raman probes, and scanning near-field optical microscopy.

Highly sensitive optical fiber curvature sensor based on a seven-core fiber with a twisted structure.

A highly sensitive Mach-Zehnder interferometer based on a twisted structure in seven-core fiber (SCF) for curvature measurement is investigated both theoretically and experimentally. The device is fabricated by splicing a segment of a twisted SCF with single-mode fibers by the over fusion method. An interference pattern of the straight sensor appears in the transmission spectra. When the sensor is bent, the wavelength shift of the interference pattern is induced, which may be used for curvature measurement through wavelength shift. In the experiment, SCFs with and without the twisted structure are tested, and the results are compared with wavelength-based sensitivities. The proposed twisted-SCF sensor offers a maximum curvature sensitivity of $ - {25.16}\,\,{{\rm nm/m}^{ - 1}}$-25.16nm/m-1 within the measurement range of ${0.5201 - 1.0071}\,\,{{\rm m}^{ - 1}}$0.5201-1.0071m-1, which is a 37-fold improvement compared with the previous works. The results also indicate that this highly sensitive all-fiber sensor offers great potential for realization of curvature measurement in the field of structural health monitoring.

IgG4-related kidney disease (IgG4-RKD) with membranous nephropathy as its initial manifestation: report of one case and literature review.

BACKGROUND: IgG4-related disease (IgG4-RD) often affects multiple organs and tissues, especially the kidneys, and is characterized by interstitial nephritis, obstructive nephropathy, and in rare cases glomerulopathy (including membranous nephropathy). CASE PRESENTATION: In this article, we report a patient with nephrotic syndrome as the only initial manifestation. Membranous nephropathy was confirmed by renal biopsy, but without any renal interstitial lesions. The nephrotic syndrome completely resolved after treatment with immunosuppressants but recurred after drug withdrawal, which was accompanied by acute kidney injury. Ultimately, IgG4-related interstitial nephritis with membranous nephropathy was confirmed by a second renal biopsy. After routine administration of steroids and cyclophosphamide, renal function returned to normal after 2 months, and nephrotic syndrome was ameliorated after 5 months. CONCLUSION: Special attention should be paid to this rare condition in the clinical setting. In patients with membranous nephropathy (MN) that is accompanied by multi-system damage, impaired renal function, elevated IgG4 levels (absolute or relative value), negative PLA2R, and/or renal interstitial plasma cell infiltration, the possibility of IgG4-related kidney disease (IgG4-RKD) should be carefully assessed.

Cylinder-type fiber-optic Vernier probe based on cascaded Fabry-Perot interferometers with a controlled FSR ratio.

We designed a cylinder-type fiber-optic Vernier probe based on cascaded Fabry-Perot interferometers (FPIs) in this paper. It is fabricated by inserting a short single-mode fiber (SMF) column into a large-aperture hollow-core fiber (LA-HCF) with an internal diameter of 150 µm, which structures a length adjusted air microcavity with the lead-in SMF inserted into the LA-HCF from the other end. The length of the SMF column is 537.9 µm. By adjusting the distance between the SMF column and the lead-in SMF, the spectral change is displayed intuitively, and the Vernier spectra are recorded and analyzed. In sensitivity analysis, the probe is encapsulated in the medical needle by ultraviolet glue as a small body thermometer when the length of the air microcavity is 715.5 µm. The experiment shows that the sensitivity of the Vernier envelope is 12.55 times higher than that of the high-frequency comb. This design can effectively reduce the preparation difficulty of the optical fiber Vernier sensor based on cascaded FPIs, and can expand the applied fields by using different fibers and materials.