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The biological reduction of N2 to ammonia requires the ATP-dependent, sequential delivery of electrons from the Fe protein to the MoFe protein of nitrogenase. It has been demonstrated that CdS nanocrystals can replace the Fe protein to deliver photoexcited electrons to the MoFe protein. Herein, light-activated electron delivery within the CdS:MoFe protein complex was achieved in the frozen state, revealing that all the electron paramagnetic resonance (EPR) active E-state intermediates in the catalytic cycle can be trapped and characterized by EPR spectroscopy. Prior to illumination, the CdS:MoFe protein complex EPR spectrum was composed of a S = 3/2 rhombic signal (g = 4.33, 3.63, and 2.01) consistent with the FeMo-cofactor in the resting state, E0. Illumination for sequential 1-h periods at 233 K under 1 atm of N2 led to a cumulative attenuation of E0 by 75%. This coincided with the appearance of S = 3/2 and S = 1/2 signals assigned to two-electron (E2) and four-electron (E4) reduced states of the FeMo-cofactor, together with additional S = 1/2 signals consistent with the formation of E6 and E8 states. Simulations of EPR spectra allowed quantification of the different E-state populations, along with mapping of these populations onto the Lowe–Thorneley kinetic scheme. The outcome of this work demonstrates that the photochemical delivery of electrons to the MoFe protein can be used to populate all of the EPR active E-state intermediates of the nitrogenase MoFe protein cycle. [ABSTRACT FROM AUTHOR]

Background: Patients with gastrointestinal cancer have a higher risk of malnutrition and postoperative infection. Objective: To investigate the nutritional status of patients with gastrointestinal cancers and factors for postoperative infections. Method: Based on the nutritional risk status, 294 patients with gastrointestinal tumours were divided into a nutritional risk group and a non-nutritional risk group, and the differences between the two groups were compared. Results: Among the included patients, 128 were at preoperative nutritional risk (43.54%); there were significant differences between the two groups in terms of age (66.25 ± 11.73 vs. 58.36 ± 10.41 years, P < 0.001), percentage of gastric cancers (39.84% vs. 28.92%, P = 0.049), percentage of stage IV tumours (60.16% vs. 45.18%, P = 0.011), total protein (64.90 ± 6.82 vs. 67.21 ± 7.41 g/L, P = 0.007), albumin (38.32 ± 4.74 vs. 41.61 ± 5.10 g/L, P < 0.001) and haemoglobin (112.72 ± 22.63 vs. 125.11 ± 22.79 g/L, P < 0.001). Multivariate logistic regression analysis showed that risk factors for postoperative infections in patients included age ≥ 60 years (odds ratio [OR] = 2.266 95%CI = 1.357–4.134), Nutrition Risk Screening (NRS)-2002 score ≥ 3 (OR = 2.183, 95%CI = 1.218–4.102), alcohol history (OR = 2.505, 95%CI = 1.370–4.683), comorbid diabetes mellitus (OR = 2.110, 95%CI = 1.381–4.023) and surgical time ≥ 6 h (OR = 2.446, 95%CI = 1.359–4.758). Conclusion: Patients with gastrointestinal cancers are at high incidence of preoperative nutritional risk, and those with an NRS-2002 score of > 3, history of alcohol consumption and surgical time of > 6 h have a higher risk of postoperative infections. [ABSTRACT FROM AUTHOR]

Despite effective countermeasures, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persists worldwide because of its ability to diversify and evade human immunity. This evasion stems from amino acid substitutions, particularly in the receptor binding domain (RBD) of the spike protein that confers resistance to vaccine-induced antibodies and antibody therapeutics. To constrain viral escape through resistance mutations, we combined antibody variable regions that recognize different RBD sites into multispecific antibodies. Here, we describe multispecific antibodies, including a trivalent trispecific antibody that potently neutralized diverse SARS-CoV-2 variants and prevented virus escape more effectively than single antibodies or mixtures of the parental antibodies. Despite being generated before the appearance of Omicron, this trispecific antibody neutralized all major Omicron variants through BA.4/BA.5 at nanomolar concentrations. Negative stain electron microscopy suggested that synergistic neutralization was achieved by engaging different epitopes in specific orientations that facilitated binding across more than one spike protein. Moreover, a tetravalent trispecific antibody containing the same variable regions as the trivalent trispecific antibody also protected Syrian hamsters against Omicron variants BA.1, BA.2, and BA.5 challenge, each of which uses different amino acid substitutions to mediate escape from therapeutic antibodies. These results demonstrated that multispecific antibodies have the potential to provide broad SARS-CoV-2 coverage, decrease the likelihood of escape, simplify treatment, and provide a strategy for antibody therapies that could help eliminate pandemic spread for this and other pathogens. Editor's summary: Monoclonal antibodies were an essential component of the COVID-19 treatment toolbox, at least until Omicron and its subvariants arose. As new variants wipe out efficacy of existing monoclonal antibodies, new options are urgently needed, especially to protect immunocompromised individuals who cannot make antibodies of their own. Here, Misasi et al. developed a series of multispecific antibodies that were able to more broadly neutralize SARS-CoV-2 pseudoviruses than their monoclonal antibody counterparts. One trivalent trispecific antibody combination was also able to prevent pseudovirus escape in vitro. To avoid heavy/light chain mispairing, the authors made that trivalent trispecific antibody into a tetravalent trispecific antibody. When administered to mice prophylactically, this antibody was able to confer protection against challenge with BA.1, BA.2, and BA.5. These data highlight the potential of multispecific antibodies as a long-term component of the COVID-19 toolbox. —Courtney Malo [ABSTRACT FROM AUTHOR]

Photodetecting units are widely used in various areas. Among all, organic photodetectors are given particular attention because of their promising applications in developing wearable and flexible devices. In this work, octyl (C8)-diketopyrrolopyrrole (DPP)-tetrabenzoporphyrin (BP)/graphene (G) films were fabricated with a design inspired by "killing two birds with one stone". The in situ synthesis of C8-DPP-BP from its precursor/G films and the formation of highly crystallized morphologies were performed through a simple one-step annealing technique. C8-DPP-BP/G transistors show a broadband response to radiations from the ultraviolet to near infrared region. With a sufficiently long annealing time (6 h), the photodetection responsivity (R) and specific detectivity (D*) are promoted 5–10 folds compared with the film with a short time (3 hours, 3 h), while the fast on/off speeds are not deteriorated (the enhancements of R and D* vary slightly with different radiations). By analyzing the morphologies of 6 h and 3 h C8-DPP-BP/G films, we suggest that the reduced boundaries in the large sheets of 6 h C8-DPP-BP/G films and the highly crystallized end-on arrangements in the vertical direction are the key structural factors for the great improvements in R and D* while keeping the fast operation speed unaffected. Charge carriers can transport within the 6 h C8-DPP-BP film in a less interrupted way, and the separation of charge carriers near the interface of C8-DPP-BP and G is facilitated by the large distance between the center of end-on C8-DPP-BP and the G plane. Thus, in this work, besides developing an efficient broadband photodetector, we also revealed the key structural features supporting the great improvements in photosensing applications, which is of importance for understanding the complicated relationships between the morphologies and optoelectronic performances of organic films. [ABSTRACT FROM AUTHOR]

Investigated mitigating effects of sodium butyrate (SB) on the inflammatory response, oxidative stress, and growth inhibition of common carp (Cyprinus carpio) (2.94 ± 0.2 g) are caused by glycinin. Six isonitrogenous and isoenergetic diets were prepared, in which the basal diet was the control diet and the Gly group diet contained 80 g/kg glycinin, while the remaining 4 diets were supplemented with 0.75, 1.50, 2.25, and 3.00 g/kg SB, respectively. The feeding trial lasted for 8 weeks, and the results indicated that supplementing the diet with 1.50–2.25 g/kg of SB significantly improved feed efficiency and alleviated the growth inhibition induced by glycinin. Hepatopancreas and intestinal protease activities and the content of muscle crude protein were significantly decreased by dietary glycinin, but supplement 1.50–2.25 g/kg SB partially reversed this result. SB (1.50–2.25 g/kg) increased the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the hepatopancreas and reduced the activities of AST and ALT in the serum. Glycinin significantly reduced immune and antioxidant enzyme activities, whereas 1.50–2.25 g/kg SB reversed these adverse effects. Furthermore, compared with the Gly group, supplement 1.50–2.25 g/kg SB eminently up-regulated the TGF-β and IL-10 mRNA, and down-regulated the IL-1β, TNF-α, and NF-κB mRNA in hepatopancreas, mid-intestine (MI), and distal intestine (DI). Meanwhile, supplement 1.50–2.25 g/kg SB activated the Keap1-Nrf2-ARE signaling pathway and upregulate CAT, SOD, and HO-1 mRNA expression in hepatopancreas, MI, and DI. Summarily, glycinin induced inflammatory response, and oxidative stress of common carp ultimately decreased the digestive function and growth performance. SB partially mitigated these adverse effects by activating the Keap1-Nrf2-ARE signaling pathway and inhibiting the NF-κB signaling pathway. [ABSTRACT FROM AUTHOR]

Sensitive detection of nitrogen dioxide (NO2) is of significance in many areas for health and environmental protections. In this work, we developed an efficient NO2 sensor that can respond within seconds at room temperature, and the limit of detection (LOD) is as low as 100 ppb. Coating cyano-substituted poly(p-phenylene vinylene) (CN-PPV) films on graphene (G) layers can dope G sheets effectively to a heavy n state. The influences of solution concentrations and annealing temperatures on the n-doping effect were investigated in detail. The CN-PPV–G transistors fabricated with the optimized parameters demonstrate active sensing abilities toward NO2. The n-doping state of CN-PPV–G is reduced dramatically by NO2, which is a strong p-doping compound. Upon exposure to 25 ppm of NO2, our CN-PPV–G sensors react in 10 s, indicating it is almost an immediate response. LOD is determined as low as 100 ppb. The ultrahigh responding speed and low LOD are not affected in dry air. Furthermore, cycling use of our sensors can be realized through simple annealing. The superior features shown by our CN-PPV–G sensors are highly desired in the applications of monitoring the level of NO2 in situ and setting immediate alarms. Our results also suggest that transfer curves of transistors can react very promptly to the stimulus of target gas and, thus, are very promising in the development of fast-response sensing devices although the response values may not reach maximum as a tradeoff. [ABSTRACT FROM AUTHOR]

Study of α-V70I-substituted nitrogenase MoFe protein identified Fe6 of FeMo-cofactor (Fe7S9MoC-homocitrate) as a critical N2 binding/reduction site. Freeze-trapping this enzyme during Ar turnover captured the key catalytic intermediate in high occupancy, denoted E4(4H), which has accumulated 4[e−/H+] as two bridging hydrides, Fe2–H–Fe6 and Fe3–H–Fe7, and protons bound to two sulfurs. E4(4H) is poised to bind/reduce N2 as driven by mechanistically-coupled H2 reductive-elimination of the hydrides. This process must compete with ongoing hydride protonation (HP), which releases H2 as the enzyme relaxes to state E2(2H), containing 2[e−/H+] as a hydride and sulfur-bound proton; accumulation of E4(4H) in α-V70I is enhanced by HP suppression. EPR and 95Mo ENDOR spectroscopies now show that resting-state α-V70I enzyme exists in two conformational states, both in solution and as crystallized, one with wild type (WT)-like FeMo-co and one with perturbed FeMo-co. These reflect two conformations of the Ile residue, as visualized in a reanalysis of the X-ray diffraction data of α-V70I and confirmed by computations. EPR measurements show delivery of 2[e−/H+] to the E0 state of the WT MoFe protein and to both α-V70I conformations generating E2(2H) that contains the Fe3–H–Fe7 bridging hydride; accumulation of another 2[e−/H+] generates E4(4H) with Fe2–H–Fe6 as the second hydride. E4(4H) in WT enzyme and a minority α-V70I E4(4H) conformation as visualized by QM/MM computations relax to resting-state through two HP steps that reverse the formation process: HP of Fe2–H–Fe6 followed by slower HP of Fe3–H–Fe7, which leads to transient accumulation of E2(2H) containing Fe3–H–Fe7. In the dominant α-V70I E4(4H) conformation, HP of Fe2–H–Fe6 is passively suppressed by the positioning of the Ile sidechain; slow HP of Fe3–H–Fe7 occurs first and the resulting E2(2H) contains Fe2–H–Fe6. It is this HP suppression in E4(4H) that enables α-V70I MoFe to accumulate E4(4H) in high occupancy. In addition, HP suppression in α-V70I E4(4H) kinetically unmasks hydride reductive-elimination without N2-binding, a process that is precluded in WT enzyme. [ABSTRACT FROM AUTHOR]

Langevin dynamics simulations are employed to explore the effects of chain stiffness and electrostatic interaction (EI) on the conformational behavior of a circular semiflexible polyelectrolyte (CSPE) in presence of trivalent counterions. We investigate the effect of bending energy b and the dimensionless Bjerrum length A on the conformational behaviour of the CSPE with a fixed chain length. The competition among the EIs, chain stiffness and entropy of the system leads to rich conformations for the CSPE. As the b is less than or equal to 50, The shape of the CSPE changes from a oblate ring to a rod at small A, then to a toroid at intermediate A, and finally to a globule at very large A. However, the globular conformation is not observed for large b. In addition, we find that the number of torus ring increases with A increase, while decreases with b increase. This study should be helpful in gaining insight into the conformational behaviour of charged biopolymer. [ABSTRACT FROM AUTHOR]

The significant influence of noncovalent interactions on catalytic processes has been recently appreciated but is still in its infancy. In this report, it is found that wedging Me-PTCDI (small-molecule) between the alkyl chains of PffBT4T-2OD (polymer) and a graphite substrate can reduce the energy barrier of flipping over the surface-adsorbed alkylthiophene group from the cis to syn conformation, revealing the catalytic role of Me-PTCDI via a noncovalent wedging effect. The wedging of Me-PTCDI brings the interactions between the alkyl chains and substrate to a very weak level by lifting up the alkyl chains, which eliminates the major hindrance of the flipping process to one main factor: the torsion of the dihedral angles of the thiophene group. The Me-PTCDI/syn PffBT4T-2OD arrangement shows unusual stability compared to the cis one because the syn conformation allows the alkyl chains to construct dense lamella and facilitates interactions between Me-PTCDI and the syn PffBT4T-2OD backbones. The results are helpful for boosting the development of noncovalent catalysis and bottom-up fabrications toward devices functionalized at a molecular level. [ABSTRACT FROM AUTHOR]

Purpose: Polycystic ovary syndrome is a complex heterogeneous endocrine disorder associated with established metabolic abnormalities and is a common cause of infertility in females. Glutathione metabolism in the cumulus cells (CCs) of women with PCOS may be correlated to the quality of oocytes for infertility treatment; therefore, we used a metabolomics approach to examine changes in CCs from women with PCOS and oocyte quality. Methods: Among 135 women undergoing fertility treatment in the present study, there were 43 women with PCOS and 92 without. CCs were collected from the two groups and levels of pyroglutamic acid were measured using LC–MS/MS followed by qPCR and Western blot analysis to examine genes and proteins involved in pyroglutamic acid metabolism related to glutathione synthesis. Results: Women with PCOS showed increased levels of l-pyroglutamic acid, l-glutamate, and l-phenylalanine and decreased levels of Cys–Gly and N-acetyl-l-methionine. Gene expression of OPLAH, involved in pyroglutamic synthesis, was significantly increased in women with PCOS compared with those without. Gene expression of GSS was significantly decreased in women with PCOS and synthesis of glutathione synthetase protein was decreased. Expression of nuclear factor erythroid 2-related factor 2, involved in resistance to oxidative stress, was significantly increased in women with PCOS. Conclusions: CCs of women with PCOS showed high concentrations of pyroglutamic acid and reduced glutathione synthesis, which causes oxidative stress in CCs, suggesting that decreased glutathione synthesis due to high levels of pyroglutamic acid in CCs may be related to the quality of oocytes in women with PCOS. [ABSTRACT FROM AUTHOR]

Microstructure and mechanical properties of non-equiatomic (CuNi)100−xCox (x=15, 20, 25 and 30, at.%) medium-entropy alloys (MEAs) prepared by vacuum arc-melting were investigated. Results show that all the as-cast MEAs exhibit dual face-centered cubic (fcc) solid-solution phases with identical lattice constant, showing typical dendrite structure consisting of (Ni, Co)-rich phase in dendrites and Cu-rich phase in inter-dendrites. The positive enthalpy of mixing among Cu and Ni-Co elements is responsible for the segregation of Cu. With the increase of Co content, the volume fraction of (Ni, Co)-rich phase increases while the Cu-rich phase decreases, resulting in an increment of yield strength and a decrement of elongation for the (CuNi)100−xCox MEAs. Nano-indentation test results show a great difference of microhardness between the two fcc phases of the MEAs. The measured microhardness value of the (Ni, Co)-rich phase is almost twofold as compared to that of the Cu-rich phase in all the (CuNi)100−xCox MEAs. During the deformation of the MEAs, the Cu-rich phase bears the main plastic strain, whereas the (Ni, Co)-rich phase provides more pronounced strengthening. [ABSTRACT FROM AUTHOR]

To improve the reliability and accuracy of a transformer fault diagnosis model based on a backpropagation (BP) neural network, this study proposed an enhanced distributed parallel firefly algorithm based on the Taguchi method (EDPFA). First, a distributed parallel firefly algorithm (DPFA) was implemented and then the Taguchi method was used to enhance the original communication strategies in the DPFA. Second, to verify the performance of the EDPFA, this study compared the EDPFA with the firefly algorithm (FA) and DPFA under the test suite of Congress on Evolutionary Computation 2013 (CEC2013). Finally, the proposed EDPFA was applied to a transformer fault diagnosis model by training the initial parameters of the BP neural network. The experimental results showed that: (1) The Taguchi method effectively enhanced the performance of EDPFA. Compared with FA and DPFA, the proposed EDPFA had a faster convergence speed and better solution quality. (2) The proposed EDPFA improved the accuracy of transformer fault diagnosis based on the BP neural network (up to 11.11%). [ABSTRACT FROM AUTHOR]

Background: Dynamic prediction of patient mortality risk in the ICU with time series data is limited due to high dimensionality, uncertainty in sampling intervals, and other issues. A new deep learning method, temporal convolution network (TCN), makes it possible to deal with complex clinical time series data in ICU. We aimed to develop and validate it to predict mortality risk using time series data from MIMIC III dataset. Methods: A total of 21,139 records of ICU stays were analysed and 17 physiological variables from the MIMIC III dataset were used to predict mortality risk. Then we compared the model performance of the attention-based TCN with that of traditional artificial intelligence (AI) methods. Results: The area under receiver operating characteristic (AUCROC) and area under precision-recall curve (AUC-PR) of attention-based TCN for predicting the mortality risk 48 h after ICU admission were 0.837 (0.824 -0.850) and 0.454, respectively. The sensitivity and specificity of attention-based TCN were 67.1% and 82.6%, respectively, compared to the traditional AI method, which had a low sensitivity (< 50%). Conclusions: The attention-based TCN model achieved better performance in the prediction of mortality risk with time series data than traditional AI methods and conventional score-based models. The attention-based TCN mortality risk model has the potential for helping decision-making for critical patients. Trial registration: Data used for the prediction of mortality risk were extracted from the freely accessible MIMIC III dataset. The project was approved by the Institutional Review Boards of Beth Israel Deaconess Medical Center (Boston, MA) and the Massachusetts Institute of Technology (Cambridge, MA). Requirement for individual patient consent was waived because the project did not impact clinical care and all protected health information was deidentified. The data were accessed via a data use agreement between PhysioNet, a National Institutes of Health–supported data repository (https://www.physionet.org/), and one of us (Yu-wen Chen, Certification Number: 28341490). All methods were carried out in accordance with the institutional guidelines and regulations. [ABSTRACT FROM AUTHOR]

Deliberately tuning the photodetecting performances of polymer/graphene (G) hybrid films through a simple approach and understanding its underlying mechanisms are of significance for developing related devices. Herein, photodetecting features of polymer/G films are successfully tuned from broadband to IR/UV sensitive through a simple thermal treatment, providing optional working modes for varied demands. The morphologies and electronic/photodetecting properties of polymer/G hybrids are characterized in detail through atomic force microscopy, scanning electron microscopy, grazing‐incident wide angle X‐ray scattering, field effect transistor devices, and density functional theory calculations. The results suggest that the synergetic effect between Fermi level of G and morphologies of polymer film is responsible for the altered sensitivities to different radiations. The former factor shifts the energy barrier of charge carrier transferring for photocurrent generation, while the latter modifies the absorption capabilities of polymer films to the specific lights. Thus, in this work, besides proposing an in‐principle multimode photodetecting device for different applications, the intrinsic mechanisms behind the performance modifications and the robust capabilities of simple thermal treatments on tuning activities of polymer/G devices are revealed as well, which provide valuable supports for developing efficient photosensing devices in a facile and rational approach. [ABSTRACT FROM AUTHOR]

Isatuximab is a monoclonal antibody targeting the transmembrane receptor and ectoenzyme CD38, a protein highly expressed on hematological malignant cells, including those in multiple myeloma (MM). Upon binding to CD38-expressing MM cells, isatuximab is thought to induce tumor cell killing via fragment crystallizable (Fc)-dependent mechanisms, including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC), as well as via direct Fc-independent mechanisms. Here, these mechanisms of action were investigated in MM and diffuse large B-cell lymphoma (DLBCL) cell lines, as well as in peripheral blood mononuclear cells derived from healthy donors, and in MM patient-derived samples. Our findings show that isatuximab-mediated cytotoxicity occurred primarily via ADCC and ADCP in MM cell lines and via ADCC and apoptosis in DLBCL cell lines expressing high levels of CD38. We identified the programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1) pathway and MM cell-secreted transforming growth factor-beta (TGF-β) as tumor cell-related features that could suppress CD38-mediated ADCC. Furthermore, we established that isatuximab can directly activate natural killer (NK) cells and promote NK cell-mediated cytotoxicity via crosslinking of CD38 and CD16. Finally, isatuximab-induced CDC was observed in cell lines with high CD38 receptor density (>250,000 molecules/cell) and limited expression of inhibitory complement regulatory proteins (CD46, CD55, and CD59; <50,000 molecules/cell). Taken together, our findings highlight mechanistic insights for isatuximab and provide support for a range of combination therapy approaches that could be tested for isatuximab in the future. [ABSTRACT FROM AUTHOR]

Study Question: Are there any differences between in vivo (IVV) and in vitro (IVT) matured metaphase II (MII) oocytes at the molecular level?Summary Answer: Between IVV and IVT oocytes, 507 differentially expressed genes (DEGs) were identified; the non-CpG methylomes were significantly different, but the CpG methylomes and genomic copy number variations (CNVs) were similar.What Is Known Already: A previous study using microarray and single-cell RNA-seq analysis revealed that numerous genes were differentially expressed between IVV and IVT oocytes. Independent studies of DNA methylation profiling in human oocytes have revealed negative correlations between gene transcription and the DNA methylation level at gene promoter regions. No study has compared global CpG or non-CpG methylation between these two groups of oocytes. Although a high level of aneuploidy has been reported in MII oocytes, no direct comparison of IVV and IVT oocytes based on single-cell sequencing data has been performed.Study Design, Size, Duration: We collected eight IVV oocytes from six patients and seven IVT oocytes from seven patients and then analysed each oocyte using the previously established single-cell triple omics sequencing (scTrioseq) analysis to determine associations among the transcriptome, DNA methylome and chromosome ploidy in the oocytes.Participants/materials, Setting, Methods: All IVV oocytes were donated by patients who received 150 IU gonadotropin per day from the third day of their menstrual cycle, followed by GnRH antagonist after 5 days of gonadotropin stimulation. All IVT oocytes were from immature oocytes which were donated by volunteers undergoing delivery by caesarean section then cultured in oocyte maturation medium containing 75 mIU/ml hMG for 24 to 48 h. Every single oocyte was analysed using the previously established single-cell multiomic sequencing analysis.Main Results and the Role Of Chance: There were 507 genes differentially expressed between the IVV (n = 8) and IVT (n = 7) oocytes, even though their global transcriptome profiles were similar. The enriched genes in IVV oocytes were related to the cell cycle process while those in IVT oocytes were related to mitochondrial respiration biogenesis. Although the global CpG methylation of the two groups of oocytes was similar, the non-CpG methylation level in IVV oocytes was higher than that in IVT oocytes. A high aneuploidy ratio was found in both groups, but the aneuploidy did not affect transcription according to the correlation analysis.Large-scale Data: N/A.Limitations and Reasons For Caution: Due to the difficulty in collecting MII oocytes, especially IVV matured oocytes, the sample size was limited.Wider Implications Of the Findings: Our findings indicate that single-cell multiomic sequencing can be utilised to examine the similarity and differences between IVV and IVT matured MII oocytes.Study Funding/competing Interest(s): This work was supported by the Ministry of Science and Technology of China, National Key R&D Program of China (No. 2017YFC1001601). The donated oocytes were collected by Shanghai Tenth People's Hospital. The authors declare no competing interests. [ABSTRACT FROM AUTHOR]

Background: Neural stem cells (NSCs) transplantation is considered a promising treatment for Parkinson's disease. But most NSCs are differentiated into glial cells rather than neurons, and only a few of them survive after transplantation due to the inflammatory environment. Methods: In this study, neural stem cells (NSCs) and microglial cells both forced with the Nurr1 gene were transplanted into the striatum of the rat model of PD. The results were evaluated through reverse transcription polymerase chain reaction (RT‐PCR), Western blot, and immunofluorescence analysis. Results: The behavioral abnormalities of PD rats were improved by combined transplantation of NSCs and microglia, both forced with Nurr1. The number of tyrosine hydroxylase+ cells in the striatum of PD rats increased, and the number of Iba1+ cells decreased compared with the other groups. Moreover, the dopamine neurons differentiated from grafted NSCs could still be detected in the striatum of PD rats after 5 months. Conclusions: The results suggested that transplantation of Nurr1‐overexpressing NSCs and microglia could improve the inhospitable host brain environments, which will be a new potential strategy for the cell replacement therapy in PD. [ABSTRACT FROM AUTHOR]

Aim: To investigate the effectiveness of over-the-scope-clip (OTSC)-based endoscopic closure in patients with perforated peptic ulcer (PPU).Methods: One hundred six patients diagnosed with PPU were treated with either OTSC (n = 26) or conservative treatments (n = 80), respectively. The outcome assessments included technical success rate, clinical success rate, post-treatment complications after 1 month, mortality rate, time to resume oral feeding, length of hospital stay, and the administration of antibiotics.Results: In the OTSC group, technical and clinical success was achieved in 100% of patients without any complications, including death, incomplete closure, duodenal obstruction, and gastrointestinal bleeding, with a median operation time of 10 min. All patients in the OTSC group were discharged, while the mortality rate in the control group was 13.8%. Subsequent surgeries were required in 30% of patients in the control group. The median times to resume oral feeding were 3.5 (interquartile range [IQR] 2.0-5.25) days in the OTSC group and 7.0 (IQR 5.0-9.0) days in the control group (p < 0.001). One month post-procedure, 30% (24/80) of patients in the control group and 0 (0/26) in the OTSC group required additional operations (p < 0.001). No significant difference was found in the length of the hospital stay and the administration of antibiotics between the two groups (p > 0.05).Conclusions: OTSC-based endoscopic technique, with a high clinical success rate and a shorter time to resume oral feeding, was effective in achieving closure of PPU with a diameter < 15 mm. [ABSTRACT FROM AUTHOR]

Cerebral blood flow (CBF) reduction underlies unfavorable outcomes after subarachnoid hemorrhage (SAH). Transient receptor potential melastatin-4 (TRPM4) has a pivotal role in cerebral artery myogenic tone maintenance and CBF regulation under physiological conditions. However, the role of TRPM4 in CBF reduction after SAH is unclear. In this study, we aimed at testing whether TRPM4 would contribute to CBF reduction after SAH in vivo and determining underlying mechanisms. Rat SAH model was established by stereotaxic injection of autologous nonheparinized arterial blood at the suprasellar cistern. A TRPM4 blocker, 9-phenanthrol (9-Phe), was infused through an intraventricular catheter connected to a programmed subcutaneous pump to evaluate the contribution of TRPM4 to SAH outcomes. TRPM4 expression and translocation in cerebral artery myocytes were detected by immunoblotting. Macroscopic currents in cerebral artery myocytes were determined by whole-cell patch clamp. Myogenic tone of cerebral arteries was studied by pressurized myography. Cortical and global CBFs were measured via laser Doppler flowmetry and fluorescent microspheres, respectively. After SAH, TRPM4 translocation and macroscopic current density increased significantly. Furthermore, TRPM4 accounted for a greater proportion of myogenic tone after SAH, suggesting an upregulation of TRPM4 activity in response to SAH. Cortical and global CBFs were reduced after SAH, but were restored significantly by 9-Phe, implying that TRPM4 contributed to CBF reduction after SAH. Collectively, these discoveries show that increased TRPM4 activity has a pivotal role in CBF reduction after SAH, and provide a novel target for the management of cerebral perfusion dysfunction following SAH. [ABSTRACT FROM AUTHOR]

Summary: Introduction: Neural stem cells (NSCs) are the most promising cells for cell replacement therapy for Parkinson's disease (PD). However, a majority of the transplanted NSCs differentiated into glial cells, thereby limiting the clinical application. Previous studies indicated that chronic neuroinflammation plays a vital role in the degeneration of midbrain DA (mDA) neurons, which suggested the developing potential of therapies for PD by targeting the inflammatory processes. Thus, Nurr1 (nuclear receptor‐related factor 1), a transcription factor, has been referred to play a pivotal role in both the differentiation of dopaminergic neurons in embryonic stages and the maintenance of the dopaminergic phenotype throughout life. Aim: This study investigated the effect of Nurr1 on neuroinflammation and differentiation of NSCs cocultured with primary microglia in the transwell coculture system. Results: The results showed that Nurr1 exerted anti‐inflammatory effects and promoted the differentiation of NSCs into dopaminergic neurons. Conclusions: The results suggested that Nurr1 protects dopaminergic neurons from neuroinflammation insults by limiting the production of neurotoxic mediators by microglia and maintain the survival of transplanted NSCs. These phenomena provided a new theoretical and experimental foundation for the transplantation of Nurr1‐overexpressed NSCs as a potential treatment of PD. [ABSTRACT FROM AUTHOR]

Direct percutaneous endoscopic jejunostomy (DPEJ) is a useful method for the establishment of enteral nutrition (EN) pathway. However, the identification of stomal puncture points for DPEJ is difficult. Here we present a case treated with an improved technique for DPEJ puncture-point localization, which was named DPEJ with balloon-assisted ultrasonic localization (DPEJ-BAUL). There were four steps after insertion of an endoscope into the jejunum: (1) a balloon dilatation catheter was inserted through the endoscope working channel; (2) the balloon was fully filled with water; (3) the site of puncture was selected with an ultrasonic probe percutaneously locating the water-filled balloon; and (4) a jejunostomy tube was placed by introducer technique. Rapid localization of a puncture site was possible with BAUL and the DPEJ procedure was successful. The patient's nutritional status was improved with EN and no postoperative complications were observed. DPEJ-BAUL is a feasible and effective technique to increase the technical success rate of DPEJ in patients with negative transillumination test results. [ABSTRACT FROM AUTHOR]

With the development of computing technologies, computer-based simulation methods have gained increasing attention in reliability analysis of engineering systems, among which subset simulation (SS) provides a robust yet efficient tool for exploring system rare failure events and evaluating system reliability. However, the component limit state functions (LSFs) of a system can be formulated in different forms (e.g., linear, exponential, and scaled), depending on mathematical modeling of the engineering systems concerned. This affects the system LSF and the performance of SS, and may lead to inconsistent system reliability analysis results. This study systematically explores effects of the functional form of component LSFs on the performance of SS in system reliability analysis and accounts for such effects from the perspective of sampling procedures. It is found that the efficient generation of conditional samples during SS, which is pivotal to the success of SS, is affected by the functional form of component LSFs in the system concerned. The performance of SS can be sensitive to the functional form of component LSFs. Normalizing component LSFs eliminate the effects of scaled LSFs on the performance of SS, but it does not improve the robustness (insensitivity) of SS in system reliability analysis involving exponential LSFs that are nonlinear. Understanding the effects of component LSFs on the performance of SS, a generalized SS (GSS) algorithm is proposed for system reliability analysis, which is robust to different functional forms of component LSFs provided that the functional transformation of component LSFs does not change their monotonicity and failure domains. Numerical examples and a real engineering example showed that the proposed algorithm is more robust to the functional form of component LSFs in system reliability analysis than standard SS. [ABSTRACT FROM PUBLISHER]

A polymer (poly(9,10-anthracenevinylene- alt-4,4'-(9,9-bis(4-(4'-(1,2,2'-triphenylvinyl)phenoxy)butyl)-9 H-fluorene-2,7-diyl) dibenzaldehyde), P1 was successfully synthesized through the Wittig-Horner reaction by employing fluorene and 9,10-distyrylanthracene moieties as building blocks for backbone and tetraphenylethenes as pendant groups. Photophysical and thermal properties of the resulting polymeric emitter were fully characterized by ultraviolet-visible (UV-Vis) absorption and photoluminescence (PL) spectra, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). While P1 emits an orange-light centered at 567 nm in dilute tetrahydrofuran (THF) solution, the solid powder of the polymer exhibits strong yellow emission peaked at 541 nm. It is also found that the as-synthesized polymer shows unique property of aggregation-enhanced emission (AEE). In addition, P1 possesses high thermal stability with a decomposition temperature ( T of 430 °C and high morphological stability with a glass transition temperature ( T of 171 °C. Under the stimulus of mechanical force, the emission of P1 can be changed from yellow to red (Δ λ = 61 nm), showing a remarkable mechanochromism. The results from XRD analysis suggest that such mechanochromic phenomenonof P1 is probably caused by the destruction of crystalline structure, which leads to the conformational planarization of the distyrylanthracene moieties forming by the polymerization and the increase of molecular conjugation of the backbone. [ABSTRACT FROM AUTHOR]

Correction for 'Noncovalent wedging effect catalyzed the cis to syn transformation of a surface-adsorbed polymer backbone toward an unusual thermodynamically stable supramolecular product' by Zhi-Xuan Liu et al., Phys. Chem. Chem. Phys., 2022, 24, 30010–30016, https://doi.org/10.1039/D2CP04184G. [ABSTRACT FROM AUTHOR]

We combine cryoreduction/annealing/EPR measurements of nitrogenase MoFe protein with results of earlier investigations to provide a detailed view of the electron/proton transfer events and conformational changes that occur during early stages of [e−/H+] accumulation by the MoFe protein. This includes reduction of: 1) the non-catalytic state of the iron-molybdenum cofactor (FeMo-co) active site that is generated by chemical oxidation of the resting-state cofactor ( S=3/2) within resting MoFe (E0); and 2) the catalytic state that has accumulated n=1 [e−/H+] above the resting-state level, denoted E1(1H) ( S≥1) in the Lowe-Thorneley kinetic scheme. FeMo-co does not undergo a major change of conformation during reduction of oxidized FeMo-co. In contrast, FeMo-co undergoes substantial conformational changes during the reduction of E0 to E1(1H), and of E1(1H) to E2(2H) ( S=3/2). The experimental results further suggest that the E1(1H)→E2(2H) step involves coupled delivery of a proton and an electron (PCET) to FeMo-co of E1(H) to generate a nonequilibrium S= [ABSTRACT FROM AUTHOR]

Over the past decades, cancer has become one of the toughest challenges for health professionals. The epidemiologists are increasingly directing their research efforts on various malignant tumor worldwide. Of note, incidence of cancers is on the rise more quickly in developed countries. Indeed, great endeavors have to be made in the control of the life-threatening disease. As we know it, pancreatic cancer (PC) is a malignant disease with the worst prognosis. While little is known about the etiology of the PC and measures to prevent the condition, so far, a number of risk factors have been identified. Genetic factors, pre-malignant lesions, predisposing diseases and exogenous factors have been found to be linked to PC. Genetic susceptibility was observed in 10% of PC cases, including inherited PC syndromes and familial PC. However, in the remaining 90%, their PC might be caused by genetic factors in combination with environmental factors. Nonetheless, the exact mechanism of the two kinds of factors, endogenous and exogenous, working together to cause PC remains poorly understood. The fact that most pancreatic neoplasms are diagnosed at an incurable stage of the disease highlights the need to identify risk factors and to understand their contribution to carcinogenesis. This article reviews the high risk factors contributing to the development of PC, to provide information for clinicians and epidemiologists. [ABSTRACT FROM AUTHOR]

This study aimed to examine the clinical efficacy of minimally invasive percutaneous catheter drainage (PCD) versus open laparotomy with temporary closure in the treatment of abdominal compartment syndrome (ACS) in patients with early-stage severe acute pancreatitis (SAP). Clinical data of 212 patients who underwent PCD and 61 patients who were given open laparotomy with temporary closure in our hospital over the last 10-year period were retrospectively analyzed, and outcomes were compared, including total and post-decompression intensive care unit (ICU) and hospital stays, physiological data, organ dysfunction, complications, and mortality. The results showed that the organ dysfunction scores were similar between the PCD and open laparotomy groups 72 h after decompression. In the PCD group, 134 of 212 (63.2%) patients required postoperative ICU support versus 60 of 61 (98.4%) in the open laparotomy group ( P<0.001). Additionally, 87 (41.0%) PCD patients experienced complications as compared to 49 of 61 (80.3%) in the open laparotomy group ( P<0.001). There were 40 (18.9%) and 32 (52.5%) deaths, respectively, in the PCD and open laparotomy groups ( P<0.001). In conclusion, minimally invasive PCD is superior to open laparotomy with temporary closure, with fewer complications and deaths occurring in PCD group. [ABSTRACT FROM AUTHOR]

Brain-derived neurotrophic factor (BDNF) plays important roles in neural stem cell (NSC) growth. In this study, we investigated whether BDNF exerts its neurotrophic effects through the Wnt/β-catenin signaling pathway in human embryonic spinal cord NSCs (hESC-NSCs)in vitro. We found an increase in hESC-NSC growth by BDNF overexpression. Furthermore, expression of Wnt1, Frizzled1 and Dsh was upregulated, whereas GSK-3β expression was downregulated. In contrast, hESC-NSC growth was decreased by BDNF RNA interference. BDNF, Wnt1 and β-catenin components were all downregulated, whereas GSK-3β was upregulated. Next, we treated hESC-NSCs with 6-bromoindirubin-3′-oxime (BIO), a small molecule inhibitor of GSK-3β. BIO reduced the effects of BDNF upregulation/downregulation on the cell number, soma size and differentiation, and suppressed the effect of BDNF modulation on the Wnt signaling pathway. Our findings suggest that BDNF promotes hESC-NSC growthin vitrothrough crosstalk with the Wnt/β-catenin signaling pathway, and that this interaction may be mediated by GSK-3β. [ABSTRACT FROM PUBLISHER]

Objective: To analyze the clinical features of children with hand foot and mouth disease (HFMD) who died.Methods: 331 deaths due to HFMD between 2010 and 2014 were included in this retrospective study; 15 autopsies were performed.Results: Most deaths were seen in children aged below 3 y, and with enterovirus 71 infection (91%). The mean (SD) duration of HFMD from onset to death was 3.7(2.9) d. The mean (SD) age of fast progressors (from onset to death less than 4 days) was 17.4 (9.2) mo. Most of them were diagnosed as stage 3 and stage 4 of HFMD. Various pathological changes were observed in brain after autopsy, especially in brain stem and medulla.Conclusions: The brain stem encephalitis with the neurotropism of enteroviruses seems to be the main contributor to the death in HFMD. [ABSTRACT FROM AUTHOR]

Drought is a kind of extreme hydrological event. With the penetration of climate change impact, severity, areal extent, and frequency of drought are increasing, especially in Huang-Huai-Hai River Basin, which plays a key role in China's agriculture production. Analyzing the regional temporal and spatial variability in the context of climate change could provide a basis for the evasion of disasters and risk. The maximum number of consecutive dry days was selected as the indicator to analyze the decadal variability of drought severity, areal extent, and spatial variability of drought frequency in different seasons in Huang-Huai-Hai River Basin. Based on these, temporal and spatial variability of two kinds of special extreme events-consecutive drought and heavy rain after drought-were studied. The results showed that: (1) Huang-Huai-Hai River Basin mainly experienced moderate drought and severe drought. Moderate drought mainly occurs in autumn. High-frequency region of moderate drought is located in the plain of Huang-Huai-Hai River Basin, and its area is approximately 22.7 % of Huang-Huai-Hai River Basin. Severe drought often occurs in spring with high-frequency region in the upstream of the Yellow River. The area of this high-frequency region is about 6 % of Huang-Huai-Hai River Basin. (2) During 1961~2011, the areal extent of summer severe drought, autumn severe drought, and extreme drought all showed increasing trend, in which the increasing trend of the autumn severe drought area in the Yellow River has reached the significance level α = 0.05. (3) Consecutive drought of several seasons often took place in Ningxia plain and Hetao plain which lie in the northwest of the Yellow River Basin. In the recent 20 years, consecutive drought from spring to summer and consecutive drought from summer to autumn occurred frequently. Drought-flood abrupt alternation such as heavy rain after drought often occurred in summer temporally and Huaihe River Basin spatially. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) involves the activation of a previously administered photosensitizing agent by visible light to induce tumor necrosis. Photosensitizers are topically applied in the treatment of skin tumors to avoid systemic side effects. In this study, we evaluated the feasibility and efficacy of aminolevulinic acid (ALA) as a photosensitizer (ALA-PDT) in combination with CO2 laser in the treatment of Bowen's disease (BD; intraepithelial squamous cell carcinoma). Twenty-two lesions from 18 patients were randomized into two groups: 11 lesions were treated with topical ALA-PDT (180 J/cm(2) at 100 mW/cm(2)) + CO2 laser for one to three sessions. The remaining 11 lesions were treated with CO2 laser alone, serving as control group. All patients were reviewed at ≤1-week intervals. Biopsies were taken from BD lesions prior to treatment. The initial evaluation was undertaken 1 month after treatment, and biopsies were harvested for histological evaluation. Patients who did not respond to the three sessions of treatment were referred to surgical treatment. In the ALA-PDT + CO2 laser group, 72.73 % (8/11) of BD lesions showed complete remission, with an overall clearance of 90.91 %, and only one recurred (9 %) during follow-up. Local side effects included mild erythema, edema, erosion, and burning and/or stinging sensation. No systemic side effects were observed. In the control group, 63.63 % (7/11) of lesions had complete remission and the overall clearance was 54.55 %. However, five lesions (45.45 %) had recurrence. Local side effects included mild to moderate edema, erosion, ulceration, delayed healing, prolonged pain, and scarring. There existed a significant difference in recurrence rate between the two groups (P < 0.05). Moreover, after ALA-PDT plus CO2 laser treatment, complete necrosis was observed in responsive lesions, and 3 months later, the atypical BD cells were replaced by normal keratinocytes. Topical ALA-PDT in combination with CO2 laser is safe, effective, and is associated with low recurrence and reduced side effects. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) involves the activation of a previously administered photosensitizing agent by visible light to induce tumor necrosis. Photosensitizers are topically applied in the treatment of skin tumors to avoid systemic side effects. In this study, we evaluated the feasibility and efficacy of aminolevulinic acid (ALA) as a photosensitizer (ALA-PDT) in combination with CO laser in the treatment of Bowen's disease (BD; intraepithelial squamous cell carcinoma). Twenty-two lesions from 18 patients were randomized into two groups: 11 lesions were treated with topical ALA-PDT (180 J/cm at 100 mW/cm) + CO laser for one to three sessions. The remaining 11 lesions were treated with CO laser alone, serving as control group. All patients were reviewed at ≤1-week intervals. Biopsies were taken from BD lesions prior to treatment. The initial evaluation was undertaken 1 month after treatment, and biopsies were harvested for histological evaluation. Patients who did not respond to the three sessions of treatment were referred to surgical treatment. In the ALA-PDT + CO laser group, 72.73 % (8/11) of BD lesions showed complete remission, with an overall clearance of 90.91 %, and only one recurred (9 %) during follow-up. Local side effects included mild erythema, edema, erosion, and burning and/or stinging sensation. No systemic side effects were observed. In the control group, 63.63 % (7/11) of lesions had complete remission and the overall clearance was 54.55 %. However, five lesions (45.45 %) had recurrence. Local side effects included mild to moderate edema, erosion, ulceration, delayed healing, prolonged pain, and scarring. There existed a significant difference in recurrence rate between the two groups ( P < 0.05). Moreover, after ALA-PDT plus CO laser treatment, complete necrosis was observed in responsive lesions, and 3 months later, the atypical BD cells were replaced by normal keratinocytes. Topical ALA-PDT in combination with CO laser is safe, effective, and is associated with low recurrence and reduced side effects. [ABSTRACT FROM AUTHOR]

It is hard to obtain a high ductility resin transfer moulding (RTM) epoxy resin while maintaining relatively high modulus and Tg due to the requirement of low viscosity. In the paper, a high breaking elongation (6.1–8.3 %) RTM epoxy system with relatively high modulus (≥3.0 GPa) and Tg (84–115 °C) has been achieved by a novel toughening approach. The simultaneous control of chain segment structural flexibility and crosslink density through the flexible/rigid hardener ratio (D-230/DETDA) and the reaction temperature was proposed for the simultaneous toughening and stiffening of the epoxy resin. Control experiments revealed that epoxy 830 played an important part in the acquirement of high ductility for all these RTM epoxy resin formulas due to the formation of low crosslink density and relatively flexile structure. The fracture surfaces of the epoxy samples examined by scanning electron microscopy (SEM) confirmed the toughening results. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the etiology, pathological characteristics, management and prognosis of chronic pancreatitis in the Chinese population. The clinical data of 142 patients with chronic pancreatitis were retrospectively studied. All patients were of Chinese nationality and hospitalized from January 2008 to December 2011. Their ages ranged from 14 to 76 years, with a mean of 43 years. Of 142 patients, there were 72 cases of obstructive chronic pancreatitis (50.70%), 19 cases of alcoholic chronic pancreatitis (13.38%), 14 cases of autoimmune pancreatitis (9.86%) and 37 cases of undetermined etiology (26.06%). Pathologically, the average inflammatory mass diameter was 3.8±3.3 cm, biliary obstruction occurred in 36 cases, gall stones in 70 cases, calcification in 88 cases, ductal dilatation in 61 cases, side branch dilatation in 32 cases, ductal irregularity in 10 cases, lymphocytic inflammation in 23 cases, obliterative phlebitis in 14 cases, extra pancreatic lesion in 19 cases and fibrosis in 142 cases. Location of pancreatic lesion in the region of head ( n=97), neck ( n=16), body ( n=12), tail ( n=15) and whole pancreas ( n=2) influenced the choice of surgical procedures. Ninety-four patients (66.20%) received surgical treatment and 33.80% received other treatments. After operation, 80.85% of 94 patients experienced decreased pain, and 8.51% of 94 showed recovery of endocrine function but with a complication rate of 12.77%. All the operations were performed successfully. According to the pain scale of European Organization for Research and Treatment of Cancer (QLQ-C30) a decrease from 76±22 to 14±18 was observed. Etiology, pathological characteristics, management and prognosis of chronic pancreatitis in the Chinese population vary from others. [ABSTRACT FROM AUTHOR]

To protect against human immunodeficiency virus (HIV-1) infection, broadly neutralizing antibodies (bnAbs) must be active at the portals of viral entry in the gastrointestinal or cervicovaginal tracts. The localization and persistence of antibodies at these sites is influenced by the neonatal Fc receptor (FcRn), whose role in protecting against infection in vivo has not been defined. Here, we show that a bnAb with enhanced FcRn binding has increased gut mucosal tissue localization, which improves protection against lentiviral infection in non-human primates. A bnAb directed to the CD4-binding site of the HIV-1 envelope (Env) protein (denoted VRC01) was modified by site-directed mutagenesis to increase its binding affinity for FcRn. This enhanced FcRn-binding mutant bnAb, denoted VRC01-LS, displayed increased transcytosis across human FcRn-expressing cellular monolayers in vitro while retaining FcγRIIIa binding and function, including antibody-dependent cell-mediated cytotoxicity (ADCC) activity, at levels similar to VRC01 (the wild type). VRC01-LS had a threefold longer serum half-life than VRC01 in non-human primates and persisted in the rectal mucosa even when it was no longer detectable in the serum. Notably, VRC01-LS mediated protection superior to that afforded by VRC01 against intrarectal infection with simian-human immunodeficiency virus (SHIV). These findings suggest that modification of FcRn binding provides a mechanism not only to increase serum half-life but also to enhance mucosal localization that confers immune protection. Mutations that enhance FcRn function could therefore increase the potency and durability of passive immunization strategies to prevent HIV-1 infection. [ABSTRACT FROM AUTHOR]

In order to ensure that the off-line arm of a two-arm-wheel combined inspection robot can reliably grasp the line in case of autonomous obstacle crossing, a control method is proposed for line grasping based on hand-eye visual servo. On the basis of the transmission line's geometrical characteristics and the camera's imaging principle, a line recognition and extraction method based on structure constraint is designed. The line's intercept and inclination are defined in an imaging space to represent the robot's change of pose and a law governing the pose decoupling servo control is developed. Under the integrated consideration of the influence of light intensity and background change, noise (from the camera itself and electromagnetic field) as well as the robot's kinetic inertia on the robot's imaging quality in the course of motion and the grasping control precision, a servo controller for grasping the line of the robot's off-line arm is designed with the method of fuzzy control. An experiment is conducted on a 1:1 simulation line using an inspection robot and the robot is put into on-line operation on a real overhead transmission line, where the robot can grasp the line within 18 s in the case of autonomous obstacle-crossing. The robot's autonomous line-grasping function is realized without manual intervention and the robot can grasp the line in a precise, reliable and efficient manner, thus the need of actual operation can be satisfied. [ABSTRACT FROM AUTHOR]