A Miniature 3-DoF Flexible Parallel Robotic Wrist Using NiTi Wires for Gastrointestinal Endoscopic Surgery

Gastrointestinal endoscopic surgery (GES) has high requirements for instruments' size and distal dexterity, because of the narrow endoscopic channel and long, tortuous human gastrointestinal tract. This paper utilized Nickel-Titanium (NiTi) wires to develop a miniature 3-DoF (pitch-yaw-translation) flexible parallel robotic wrist (FPRW). Additionally, we assembled an electric knife on the wrist's connection interface and then teleoperated it to perform an endoscopic submucosal dissection (ESD) on porcine stomachs. The effective performance in each ESD workflow proves that the designed FPRW has sufficient workspace, high distal dexterity, and high positioning accuracy.Comment: IEEE International Conference on Robotics and Automation (ICRA) 2022 workshop: Frontiers of Endoluminal Intervention: Clinical opportunities and technical challenge

The research of parallel to the grain compression performance test of laminated glued bamboo-wood composites

Istraživanje stlačivosti kompozita bambus-drvo predstavlja osnovu za izbor materijala za prednapregnute grede od bambusa i drveta i drugih komponenti čija se stlačivost uglavnom dijeli s kompozitima od lijepljenog bambusa i drveta. Odabrane su četiri vrste drveta i dvije vrste bambusa za 22 grupe (6 uzoraka u svakoj grupi) podijeljene u 4 serije za ispitivanje čimbenika koji utječu na vrstu materijala bambus/drvo, kao što su sastav, debljina ploče sloja (layer plate), i tipovi postavljanja lamela (lamina lay-ups type). Uspoređivani su i analizirani tlačna čvrstoća, modul elastičnosti, duktilnost i mehanizmi kvara. Rezultati su pokazali da je do loma uglavnom dolazilo zbog kosog smika (oblique shear failure), savijanja laminata, dok su se krajnji lokalni tlak i lom zbog uvijanja događali manje često. Tlačna čvrstoća bambusa bila je 1,5 ÷ 2 puta veća nego tlačna čvrstoća drveta. Njihov je modul elastičnosti sličan zbog čega se uobičajeno koriste u temeljima. Nakon sastavljanja, tlačna se čvrstoća povećala. Nakon sastavljanja s lijepljenim bambusom, povećala se za 1,26 ÷ 32,05 %, a s rekonsolidiranim bambusom (nanovo učvršćenim) se povećala za 0,80 ÷ 45,86 %. Kompoziti bambus-drvo imaju visoku čvrstoću i dobru duktilnost, što može zadovoljiti tehničke potrebe.Research of bamboo-wood composites compression performance provides a basis for material selections for prestressed glued bamboo-wood beams and other components whose compression is mainly shared by glued bamboo-wooden composites. Four kinds of wood and two kinds of bamboo were selected to comprise 22 groups (6 specimens each group) divided into 4 batches to study the influence factors on bamboo/wooden material type; factors such as composition pattern, layer plate thickness, and lamina lay-ups type. Compressive strength, elasticity modulus, ductility, and failure mechanisms were all compared and analysed. Results showed that failure modes were mainly oblique shear failure, laminates bending failure, laminates tackless failure, while the end local pressure and overall bending failure occured less frequently. Compressive strength of bamboo was 1,5 ÷ 2 times higher than that of wood. Elastic modulus of the two was similar, which makes them commonly used in foundations. After being compounded, compressive strength improved. After being combined with glued bamboo, it increased by 1,26 ÷ 32,05 %, and it increased by 0,80 ÷ 45,86 % with reconsolidated bamboo. Bamboo-wood composites have high strength and good ductility, which can meet engineering requirements

A New Strategy for Identification of Highly Conserved microRNAs in Non-Model Insect, Spodoptera litura

The indigenous small non-coding RNAs, known as microRNAs (miRNAs), are important regulators of gene expression and many of them are evolutionarily conserved. Whether stem-loop RT-PCR, as a sensitive method, could be utilized to clone conserved miRNAs from non-model insects lacks information. Here, three miRNAs, sli-miR-14, sli-miR-2a and sli-bantam, were cloned from Spodoptera litura by stem-loop RT-PCR. Two groups of primers were designed, and one of them performed especially well and proved stable. The sequences of two highly conserved miRNAs, sli-miR-14 and sli-miR-2a were identical to those in Drosophila melanogaster. To validate the reliability of this strategy, pre-miR-14 and pre-miR-2a in S. litura as representatives were given as well; this shared high homology with those in D. melanogaster and Bombyx mori, and both mature sequences of sli-miR-14 and sli-miR-2a in their precursors shared 100% identity to the results shown by stem-loop RT-PCR. Moreover, expression patterns of these miRNAs were investigated by real-time quantitative PCR. Sli-miR-14 and sli-miR-2a could be detected successfully and their expression patterns showed similar characteristics with those in model insects, further suggesting stem-loop RT-PCR technology can be used for identification of highly conserved miRNAs in non-model insects. These results provide a simplified and efficient strategy for studying the structure and function of highly conserved miRNAs, especially some critical miRNAs in non-model insects

Phase II of the LAMOST-Kepler/K2 survey. I. Time series of medium-resolution spectroscopic observations

Phase \RNum{2} of the LAMOST-{\sl Kepler/K}2 survey (LK-MRS), initiated in 2018, aims at collecting medium-resolution spectra ($R\sim7,500$; hereafter MRS) for more than $50,000$ stars with multiple visits ($\sim60$ epochs) over a period of 5 years (2018 September to 2023 June). We selected 20 footprints distributed across the {\sl Kepler} field and six {\sl K}2 campaigns, with each plate containing a number of stars ranging from $\sim2,000$ to $\sim 3,000$. During the first year of observations, the LK-MRS has already collected $\sim280,000$ and $\sim369,000$ high-quality spectra in the blue and red wavelength range, respectively. The atmospheric parameters and radial velocities for $\sim259,000$ spectra of $21,053$ targets were successfully calculated by the LASP pipeline. The internal uncertainties for the effective temperature, surface gravity, metallicity, and radial velocity are found to be $100$\,K, $0.15$\,dex, $0.09$\,dex, and $1.00$\,km\,s$^{-1}$, respectively. We found $14,997$, $20,091$, and $1,514$ stars in common with the targets from the LAMOST low-resolution survey (LRS), GAIA and APOGEE, respectively, corresponding to a fraction of $\sim70\%$, $\sim95\%$ and $\sim7.2\%$. In general, the parameters derived from LK-MRS spectra are consistent with those obtained from the LRS and APOGEE spectra, but the scatter increases as the surface gravity decreases when comparing with the measurements from APOGEE. A large discrepancy is found with the GAIA values of the effective temperature. The comparisons of radial velocities of LK-MRS to GAIA and LK-MRS to APOGEE nearly follow an Gaussian distribution with a mean $\mu\sim1.10$ and $0.73$\,km\,s$^{-1}$, respectively.Comment: 24 pages, 15 figures, 4 tables, ApJS, accepte

Synthesis of YVO4:Eu3+/YBO3Heteronanostructures with Enhanced Photoluminescence Properties

Novel YVO4:Eu3+/YBO3core/shell heteronanostructures with different shell ratios (SRs) were successfully prepared by a facile two-step method. X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy were used to characterize the heteronanostructures. Photoluminescence (PL) study reveals that PL efficiency of the YVO4:Eu3+nanocrystals (cores) can be improved by the growth of YBO3nanocoatings onto the cores to form the YVO4:Eu3+/YBO3core/shell heteronanostructures. Furthermore, shell ratio plays a critical role in their PL efficiency. The heteronanostructures (SR = 1/7) exhibit the highest PL efficiency; its PL intensity of the5D0–7F2emission at 620 nm is 27% higher than that of the YVO4:Eu3+nanocrystals under the same conditions