Ultrasound-guided Transversus Abdominis Plane Block Improves Postoperative Analgesia and Early Recovery in Patients Undergoing Retroperitoneoscopic Urologic Surgeries:A Randomized Controlled Double-blinded Trial

Objective To evaluate the effects of ultrasound-guided transversus abdominis plane(TAP) block on postoperative analgesia and early recovery in patients undergoing retroperitoneoscopic urologic surgeries.Methods This was a randomized,controlled,double-blinded trial.Eligible patients scheduled for retroperitoneoscopic urologic surgeries were randomly assigned to two groups.Group TAP received ultrasound-guided TAP block with 0.5% ropivacaine 20 ml at 30 minutes before surgery,and Group C received TAP sham block with normal saline.All patients received retroperitoneoscopic urologic surgeries under general anesthesia.The primary outcome was the severity of pain after surgery.Secondary outcomes included opioids consumption,analgesics,postoperative nausea and vomiting,time to Foley catheter removal and to passage of flatus,length of post-anesthesia care unit stay and hospital stay.Results Eighty patients completed the study,forty cases in each group.Compared to the Group C,the Group TAP had lower visual analogue scale pain scores within two postoperative days(all P<0.05).They also had less consumption of intraoperative fentanyl(2.0±0.5 vs. 3.8±0.7 μg/kg,P<0.05),reduced incidence of postoperative rescue analgesic usage(12.5% vs. 45.0%,P<0.05),and lower incidence of postoperative nausea and vomiting within postoperative 48 hours(12.5% vs. 25.0%,P<0.05) when compared to the Group C.In addition,Group TAP had a shortened post-anesthesia care unit stay(25±8 vs. 49±12 minutes,P<0.05),and a greater proportion of patients discharged within postoperative three days(57.5% vs. 35.0%,P<0.05).Conclusion Preoperative ultrasound-guided TAP block is an effective technique to improve postoperative analgesia and early recovery in patients undergoing retroperitoneoscopic urologic surgeries.

An Ultra-wide Bandwidth Low-frequency Radio Astronomical Cryogenic Receiver for FAST Telescope

This paper presents an ultra-wide bandwidth(UWB)low-frequency radio astronomical cryogenic receiver for the Five-hundred-meter Aperture Spherical radio Telescope(FAST).It covers 6.6:1 bandwidth from 0.5 to 3.3 GHz.The receiver consists of a Quad-Ridged Flared Horn(QRFH),a cryogenic microwave unit,an optical transceiver and a warm microwave and frequency mixing unit.A QRFH with a concentric-loaded dielectric spear is developed:the average return losses are larger than 20 d B;the average ports polarization isolation is 43.87 d B;the average dish efficiency is higher than 65%.Many UWB cryogenic low loss components are developed for the fabrication of a cryogenic microwave unit.The average noise temperature lower than 14.2 K and 22.5 K are achieved as referred to the input ports of cryogenic Dewar and the output of horn,respectively.Compared to other similar advanced UWB receivers,such as Parkes 0.7-4.2 GHz(6:1 bandwidth)receiver and FAST 0.27-1.62 GHz(6:1 bandwidth)receiver,wider relative bandwidth of the proposed receiver is achieved and it is a new attempt to expand the bandwidth of UWB low-frequency receiver.

Controllable Preparation of Branched Polyolefins with Various Microstructural Units via Chain-walking Ethylene and Pentene Polymerizations

Branched polyolefins with controllable topology structures were generated from the chain-walking(co)polymerizations of ethylene,1-pentene(1P)and 2-pentene(2P)using Brookhart-typeα-diimine Ni(II)-based catalysts possessing different para-substituted groups,{[(4-R-2-Et-6-Me-C6H2N=C)2Nap]NiBr2,Nap:1,8-naphthdiyl;R=CHMePh,Ni1;R=Ph,Ni2;R=H,Ni3}.The X-ray diffraction analysis demonstrated that the crystalline structure of Ni1′is in centrosymmetric dimer structure mode with the bimetallic Ni center connected by two bromide bridges.The para-sec-phenethyl moiety in the catalyst Ni1 obviously improved its catalytic performance and thermal stability in the ethylene polymerization.The Ni1/Et2AlCl system showed great catalytic activities(up to 7.73×106 g·mol-1·h-1)and achieved polyethylene(PE)with alkyl chains,including Me,Et,n-Pr,n-Bu,sec-Bu branches and longer chains(Lg).Compared with the 1-pentene polymerization,this catalyst system successfully mediated the polymerization of 2P to give highly branched polymers with approximately 195 branches/1000C possessing Me,Et,and n-Pr branches and a long methylene sequence due to the monomer isomerization.The Et branches derived from 2,3-insertion is slightly less than the sum of Me and n-Pr branches derived from 3,2-insertion,indicating that the 3,2-insertion mode is a slightly favorable pathway in the polymerization of 2P.