Neuraxial adjuvants for prevention of perioperative shivering during cesarean section: A network meta-analysis following the PRISMA guidelines

BACKGROUND Perioperative shivering is clinically common during cesarean sections under neuraxial anesthesia,and several neuraxial adjuvants are reported to have preventive effects on it.However,the results of current studies are controversial and the effects of these neuraxial adjuvants remain unclear.AIM To evaluate the effects of neuraxial adjuvants on perioperative shivering during cesarean sections,thus providing an optimal choice for clinical application.METHODS A systematic review and network meta-analysis were conducted following the PRISMA (Preferred Reported Items for Systematic Review and Meta-analysis) guidelines.Analyses were performed using Review Manager 5.3 and Stata 14.0.We searched PubMed,EMBASE,Web of Science,and Cochrane Central databases for eligible clinical trials assessing the effects of neuraxial adjuvants on perioperative shivering and other adverse events during cesarean sections.Perioperative shivering was defined as the primary endpoint,and nausea,vomiting,pruritus,hypotension,and bradycardia were the secondary outcomes.RESULTS Twenty-six studies using 9 neuraxial adjuvants for obstetric anesthesia during caesarean sections were included.The results showed that,compared with placebo,pethidine,fentanyl,dexmedetomidine,and sufentanil significantly reduced the incidence of perioperative shivering.Among the four neuraxial adjuvants,pethidine was the most effective one for shivering prevention (OR = 0.15,95%CI: 0.07-0.35,surface under the cumulative ranking curve 83.9),but with a high incidence of nausea (OR = 3.15,95%CI: 1.04-9.57) and vomiting (OR = 3.71,95%CI: 1.81-7.58).The efficacy of fentanyl for shivering prevention was slightly inferior to pethidine (OR = 0.20,95%CI: 0.09-0.43),however,it significantly decreased the incidence of nausea (OR = 0.34,95%CI: 0.15-0.79) and vomiting (OR = 0.25,95%CI: 0.11-0.56).In addition,compared with sufentanil,fentanyl showed no impact on haemodynamic stability and the incidence of pruritus.CONCLUSION Pethidine,fentanyl,dexmedetomidine,and sufentanil appear to be effective for preventing perioperative shivering in puerperae undergoing cesarean sections.Considering the risk-benefit profiles of the included neuraxial adjuvants,fentanyl is probably the optimal choice.

Absolute physical parameters of three poorly studied detached eclipsing binaries

The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral surveys.The light and radial velocity curves of each binary system were simultaneously analyzed using Wilson-Devinney(WD)code,and the absolute physical and orbital parameters of these binaries were derived.The masses of both components of ASASSN-V J063123.82+192341.9 were found to be M1=1.088±0.016 and M20.883±0.016 M⊙;those of ASAS J011416+0426.4 were determined to be M1=0.934±0.046 and M2=0.754±0.043 M⊙;and those of MW Aur were derived to be M1=2.052±0.196 and M21.939±0.193 M⊙.Finally,the evolutionary status of these detached binaries was discussed based on their absolute parameters and the theoretical stellar models.

LAMOST medium-resolution spectroscopic survey of binarity and exotic star(LAMOST-MRS-B):Observation strategy and target selection

LAMOST-MRS-B is one of the sub-surveys of LAMOST medium-resolution(R~7500)spectroscopic survey.It aims at studying the statistical properties(e.g.,binary fraction,orbital period distribution,mass ratio distribution)of binary stars and exotic stars.We intend to observe about 30000 stars(10 mag≤G<14.5 mag)with at least 10 visits in five years.We first planned to observe 25 plates around the galactic plane in 2018.Then the plates were reduced to 12 in 2019 because of the limitation of observation.At the same time,two new plates located at the high galactic latitude were added to explore binary properties influenced by the different environments.In this survey project,we set the identified exotic and low-metallicity stars with the highest observation priorities.For the rest of the selected stars,we gave the higher priority to the relatively brighter stars in order to obtain high quality spectra as many as possible.Spectra of49129 stars have been obtained in LAMOST-MRS-B field and released in DR8,of which 28828 and 3375 stars have been visited more than twice and ten times with SNR≥10,respectively.Most of the sources are B-,A-,and F-type stars with-0.6<[Fe/H]<0.4 dex.We also obtain 347 identified variable and exotic stars and about 250 stars with[Fe/H]<-1 dex.We measure radial velocities(RVs)by using 892233 spectra of the stars.The uncertainties of RV achieve about 1 km·s^(-1)and 10 km·s^(-1)for 95%of late-and early-type stars,respectively.The datasets presented in this paper are available at http://www.doi.org/10.57760/sciencedb.j00113.00035.

Newtonian limit of Einstein equation with a cosmological constant

Traditionally,the cosmological constant has been viewed as dark energy that mimics matter with negative energy.Given that matter with negative energy provides a repulsive force,which fundamentally differs from typical gravitational forces,it has been believed that the cosmological constant effectively contributes a repulsive force.However,it is important to note that the concept of gravitational force is valid only within the framework of Newtonian dynamics.In this study,we demonstrate that the traditional understanding of the gravitational force contributed by the cosmological constant is not entirely correct.Our approach involves investigating the Newtonian limit of the Einstein equation with a cosmological constant.The subtleties involved in this analysis are discussed in detail.Interestingly,we find that the effect of the cosmological constant on Newtonian gravity is an attractive force rather than a repulsive one for ordinary matter.As expected,this corrective force is negligibly small.However,our findings may offer a way to distinguish between dark energy and the cosmological constant,as one contributes a repulsive force while the other contributes an attractive force.

A photometric study of the high-mass-ratio contact binary AV Puppis

The multi-color photometric light curves for contact binary AV Puppis(AV Pup) in VRcIc bandpasses are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D) code.The solutions suggest that AV Pup is a peculiar A-subtype W UMa contact binary with a high mass ratio(q = m2/m1 = 0.896) and a low fill-out factor(f = 10%). Combining our newly determined times of minimum with those collected from literatures, the orbital period changes of this system are investigated. The O-C analysis indicates that the orbital period of AV Pup is increasing at a rate of d P/dt = 4.83 × 10-7 days yr-1, which can be explained by mass transfer from the less massive component to the more massive one.