Model-Free Large-Scale Cloth Spreading With Mobile Manipulation: Initial Feasibility Study

Cloth manipulation is common in domestic and service tasks, and most studies use fixed-base manipulators to manipulate objects whose sizes are relatively small with respect to the manipulators' workspace, such as towels, shirts, and rags. In contrast, manipulation of large-scale cloth, such as bed making and tablecloth spreading, poses additional challenges of reachability and manipulation control. To address them, this paper presents a novel framework to spread large-scale cloth, with a single-arm mobile manipulator that can solve the reachability issue, for an initial feasibility study. On the manipulation control side, without modeling highly deformable cloth, a vision-based manipulation control scheme is applied and based on an online-update Jacobian matrix mapping from selected feature points to the end-effector motion. To coordinate the control of the manipulator and mobile platform, Behavior Trees (BTs) are used because of their modularity. Finally, experiments are conducted, including validation of the model-free manipulation control for cloth spreading in different conditions and the large-scale cloth spreading framework. The experimental results demonstrate the large-scale cloth spreading task feasibility with a single-arm mobile manipulator and the model-free deformation controller.Comment: 6 pages, 6 figures, submit to CASE202

FexC enhancing the catalytic activity of FeNx in oxidative dehydration of N-heterocycles

To enhance the catalytic activity by designing metal particles combined with atomically dispersed non-noble metal catalyst is a huge challenge, which yet has not been studied widely in organic reactions. Herein, we describe a simple and efficient method to synthesize FexC combined with Fe single atoms anchored on the N-doped porous carbon by regulating pyrolysis temperature. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy corroborate the existence of atomically dispersed Fe and the coordination number between Fe and N atoms. The Fe–N–C-800 catalyst exhibits the highest catalytic activity giving the 97% yield of quinoline in dehydration of 1,2,3,4-tetrahydroquinoline (THQ) reaction at a mild condition (60 °C, O2 balloon), and it shows good stability with 80% isolated yield after five consecutive dehydration reactions. Moreover, density functional theory (DFT) calculations reveal that coexistence of FexC and FeNx structure exhibits high activity owing to the lowest adsorption energy of co-adsorbed O2 and THQ and the longest N–H bond length of THQ, that is because the existence of FexC induces the charges transfer. Our work may open a new route to design metal particles combined with atomically dispersed non-noble metal catalysts with high activity in organic synthesis

High-sensitivity and throughput optical fiber SERS probes based on laser-induced fractional reaction method

Surface-enhanced Raman scattering (SERS) is widely used in many fields, such as biosensors, medical diagnostics, materials science, and food security. Here, we report a low-cost, high-throughput laser-induced fractional reaction method for optical fiber SERS probes. Under laser irradiation, the local thermal effect and the electromagnetic interaction between nanoparticles effectively contribute to the formation and growth of silver nanoparticles on the optical fiber facet. Sodium dodecyl sulfate (SDS) solution with a concentration of 2 mM is employed as a surfactant to control the shape and size of the silver nanoparticles. A detection limit of 1.0 × 10−11 M for R6G is achieved, which is, as far as we know, the highest sensitivity that laser-induced fabricated optical fiber SERS probes have achieved. The SERS enhancement factors (EFs) are calculated to be 6.795 × 1011. The SERS intensity of R6G at peaks of 621 cm−1, 1281 cm−1, and 1359 cm−1 are measured with probes fabricated under the same condition, and showed perfect repeatability with an RSD of less than 4.5%. This new method shows effectively in fabricating optical fiber SERS probes with high sensitivity and good repeatability

Idiopathic male infertility is strongly associated with aberrant DNA methylation of imprinted loci in sperm: a case-control study

Abstract Background Male infertility is a complex disease caused by a combination of genetic, environmental, and lifestyle factors. Abnormal epigenetic programming has been proposed as a possible mechanism compromising male fertility. Recent studies suggest that aberrant imprinting in spermatozoa in a subset of infertile men is a risk factor for congenital diseases in children conceived via assisted reproduction techniques. In this study, we examined the DNA methylation status of CpG sites within the differentially methylated regions (DMRs) of three imprinted genes, H19, GNAS, and DIRAS3, using combined bisulfite PCR restriction analysis and bisulfite sequencing in sperm obtained from 135 men with idiopathic male infertility, including normozoospermia (n = 39), moderate oligozoospermia (n = 45), and severe oligozoospermia (n = 51), and fertile controls (n = 59). The percentage of global methylation was compared between fertile controls and infertile patients displaying abnormal DNA methylation status of imprinted loci. Moreover, we also analyzed whether the DNA methyltransferases (DNMTs) polymorphisms impact upon the methylation patterns of imprinted genes in idiopathic infertile males. Results Aberrant methylation patterns of imprinted genes were more prevalent in idiopathic infertile males, especially in patients with oligozoospermia. Infertile males with aberrant methylation patterns of imprinted genes displayed a tendency of lower global methylation levels, although not reaching statistical significance (P = 0.13). In the genotype-epigenotype correlation analysis, no significant association was observed between aberrant methylation patterns of the three imprinted genes and genotypes of the four DNA methyltransferase (DNMT) genes. Conclusion We conclude that abnormalities of DMR within imprinted genes may be associated with idiopathic male infertility. Disruption in methylation pattern of the three imprinted genes does not occur in high-risk genotypes of DNMTs