Unexpected thermal transport properties of MgSiO3monolayer at extreme conditions.

The thermal transport properties of mantle minerals are of paramount importance to understand the thermal evolution processes of the Earth. Here, we perform extensively structural searches of two-dimensional MgSiO3monolayer by CALYPSO method and first-principles calculations. A stable MgSiO3monolayer withPmm2 symmetry is uncovered, which possesses a wide indirect band gap of 4.39 eV. The calculations indicate the lattice thermal conductivities of MgSiO3monolayer are 49.86 W (mK)-1and 9.09 W (mK)-1inxandydirections at room temperature. Our findings suggest that MgSiO3monolayer is an excellent low-dimensional thermoelectric material with highZTvalue of 4.58 from n-type doping in theydirection at 2000 K. The unexpected anisotropic thermal transport of MgSiO3monolayer is due to the puckered crystal structure and the asymmetric phonon dispersion as well as the distinct electron states around the Fermi level. These results offer a detailed description of structural and thermal transport properties of MgSiO3monolayer at extreme conditions.

The effect of esketamine combined with propofol-induced general anesthesia on cerebral blood flow velocity: a randomized clinical trial.

BACKGROUND: Esketamine is increasingly used in clinical anesthesia. The effect of esketamine on the blood flow velocity of the middle cerebral artery has a clinical guiding effect. To investigate the effect of esketamine combined with propofol-induced general anesthesia for endotracheal intubation on the blood flow velocity of middle cerebral artery and hemodynamics during the induction period. METHODS: The randomized clinical trial included 80 patients aged 20-65 years who would undergo non-intracranial elective surgery under general anesthesia in our hospital from May 2022 to May 2023. The participants were divided into two groups based on anesthesia drugs: sufentanil 0.5µg/kg (group C) or 1.5mg/kg esketamine (group E). The primary outcome was variation value in average cerebral blood velocity. The secondary outcomes included cerebral blood flow velocities (CBFV), blood pressure (BP) and heart rate (HR) at four different time points: before induction of general anesthesia (T0), 1 min after the induction drug injected (T1), before endotracheal intubation (T2), and 1min after endotracheal intubation (T3). The occurrence of hypotension, hypertension, tearing and choking during induction was also documented. RESULTS: The variation of average CBFV from time T0 to T2(ΔVm1) and the variation from time T3 to T0 (ΔVm2) were not obviously different. The median consumption of intraoperative sufentanil in group C was obviously lower than that in group E. At T1, the mean HR of group E was significantly higher than that of group C. At T2 and T3, the BP and HR of group E were obviously higher than that of group C. At T2, the CBFV in the group E were obviously higher than those in the group C. The incidence of hypotension was significantly reduced in the group E compared with the group C. There were no differences in the other outcomes. CONCLUSIONS: The induction of esketamine combined with propofol does not increase the blood flow velocity of middle cerebral artery. Esketamine is advantageous in maintaining hemodynamic stability during induction. Furthermore, the administration of esketamine did not result in an increased incidence of adverse effects. TRIAL REGISTRATION: 15/06/2023 clinicaltrials.gov ChiCTR2300072518 https://www.chictr.org.cn/bin/project/edit?pid=176675 .

Geometric and electronic structures of medium-sized boron clusters doped with plutonium.

Doping metal heteroatoms is an effective strategy to regulate the geometric and electronic structure of boron based nanoclusters. However, the exploration of the ground state structures of metal-boron-based nanoclusters is still a challenge duo to the complexity of the bonding interactions between heterogeneous atoms and boron cluster and the number of isomers on the potential energy surface increases exponentially with cluster size. Here, we use the CALYPSO cluster structural search method in combination with density functional theory calculations to study the geometries and electronic properties of anionic boron clusters doped with plutonium (PuBn-,n= 10-20). Our results show that the medium-sized PuB14-cluster exhibits excellent stability with highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap of 2.30 eV. The remarkable stability of the anionic PuB14-cluster is due to the robust interactions between the Pu metal and the B14skeleton, along with the strong covalent interactions between the B atoms. These findings enrich the geometric structure database of metal doped clusters and provide valuable insights for the future synthesis of boron based nanomaterials.

Comparison between pericapsular nerve group (PENG) block with lateral femoral cutaneous nerve block and supra-inguinal fascia iliaca compartment block (S-FICB) for total hip arthroplasty: a randomized controlled trial.

PURPOSE: To assess the efficacy of pericapsular nerve group (PENG) block combined with lateral femoral cutaneous nerve (LFCN) block in controlling postoperative pain and promoting recovery of lower extremity after total hip arthroplasty (THA), and to compare its effectiveness with supra-inguinal fascia iliaca compartment block (S-FICB). MATERIALS AND METHODS: 92 patients undergoing THA with general anesthesia were randomly allocated to receive either a PENG with LFCN block (n = 46) using 30 ml 0.33% ropivacaine (20 ml for PENG block, 10 ml for LFCN block), or an S-FICB (n = 46) using 30 ml 0.33% ropivacaine. The primary outcome was the time to first postoperative walk. The secondary outcomes included intraoperative remifentanil consumption, postoperative hip flexion degree and muscle strength of the operative lower limbs in the supine position, pain scores (static and dynamic), rescue analgesia, postoperative nausea and vomiting (PONV), and nerve block-related complications. RESULTS: The combination of PENG with LFCN blocks resulted in an earlier first postoperative walking time (19.6 ± 9.6 h vs 26.5 ± 8.2 h, P < 0.01), greater postoperative hip flexion degree at 6 h, 24 h and 48 h (all P < 0.01), and higher muscle strength of the operative lower limbs at 6 h after surgery (P = 0.03) compared to S-FICB. The difference in pain scores (static and dynamic) was only statistically significant at 48 h (P < 0.05). There were no differences in the other outcomes. CONCLUSIONS: PENG with LFCN blocks is more effective than S-FICB in shortening the time to first postoperative walk and preservation hip motion after THA, which makes it a suitable addition to enhanced recovery programs following surgery.

95% effective volume of ropivacaine for ultrasound­guided supra­inguinal fascia iliaca compartment block.

BACKGROUND: Hip arthroplasty is effective in treating hip diseases, such as osteoarthritis and hip fracture, but it often brings severe trauma and pain. In recent years, ultrasound-guided supra-inguinal fascia iliaca compartment block(S-FICB) has become a widely used nerve block method for analgesia in hip arthroplasty. METHODS: Fifty-three patients preparing for hip arthroplasty were prospectively enrolled. S-FICB was performed under ultrasound guidance, and inject 0.33% ropivacaine into the space. Using the biased-coin design (BCD) sequential allocation method. The initial volume of 0.33% ropivacaine was 30ml. In case of failure, the next patient received a higher volume (defined as the previous volume with an increment of 1.2 mL). If the previous patient had a successful block, the next patient was randomized to a lower volume (defined as the previous volume with a decrement of 1.2 mL), with a probability of b = 0.05, or the same volume, with a probability of 1 - b = 0.95. The study was stopped when 45 successful blocks were achieved. RESULTS: Forty-five patients (84.9%) were blocked successfully. The 95% effective volume (EV95) was 34.06ml (95%CI 33.35 ~ 36.28ml). There were 31 patients with non-fracture in this study. The quadriceps muscle strength decreased in only two patients. Moreover, they both received 34.8ml of ropivacaine for S-FICB. Twenty-two patients had hip fractures. There were 3 patients (14%) with failed blocks and 19 patients (86%) with successful blocks. However, all fracture patients experienced less pain after S-FICB. CONCLUSION: EV95 of 0.33% ropivacaine for ultrasound-guided S-FICB was 34.06ml. TRIAL REGISTRATION: The trial was registered at the Chinese Clinical Trial Registry (registration number: ChiCTR2100052214, registration date: 2021 October 22).

Geometric and electronic diversity of metal doped boron clusters.

Being intermediate between small compounds and bulk materials, nanoparticles possess unique properties different from those of atoms, molecules, and bulk matter. In the past two decades, a combination of cluster structure prediction algorithms and experimental spectroscopy techniques was successfully used for exploration of the ground-state structures of pure and metal-doped boron clusters. The fruitfulness of this dual approach is well illustrated by the discovery of intriguing microstructures and unique physicochemical properties such as aromaticity and bond fluxionality for both boron and metal-doped boron clusters. Our review starts with an overview of geometrical configurations of pure boron clusters Bn, which are presented by planar, nanotube, bilayer, fullerene-like and core-shell structures, in a wide range ofnvalues. We consider next recent advances in studies of boron clusters doped with metal atoms paying close and thoughtful attention to modifications of geometric and electronic structures of pure boron clusters by heteroatoms. Finally, we discuss the possibility of constructing boron-based nanomaterials with specific functions from metal-boron clusters. Despite a variety of fruitful results obtained in numerous studies of boron clusters, the exploration of boron-based chemistry has not yet reached its peak. The intensive research continues in this area, and it should be expected that it brings exciting discoveries of intriguing new structures.

Effect of Thoracic Paravertebral Nerve Block on Blood Coagulation in Patients After Thoracoscopic Lobectomy: A Prospective Randomized Controlled Clinical Trial.

PURPOSE: Ultrasound-guided thoracic paravertebral block (TPVB) has become increasingly popular for postoperative analgesia after thoracic surgery. We designed this prospective, randomized, double-blind, placebo-controlled trial to investigate the effect of TPVB on blood coagulation in patients after thoracoscopic lobectomy. PATIENTS AND METHODS: Sixty patients scheduled for thoracoscopic lobectomy were randomly allocated to two groups. Patients underwent ultrasound-guided TPVB with 0.33% ropivacaine (T group) or 0.9% saline (C group) at the end of the surgery under general anesthesia. Patient-controlled intravenous analgesia (PCIA) was administered for both group after the surgery. The primary outcome was the thromboelastogram (TEG) parameters before anesthesia (T0), at the end of operation (T1) and in 1 day (T2) and 2 days (T3) after the operation, the second outcomes were the analgesic effect and the amount of intraoperative opioid consumption, operation time, infusion volume, blood loss and urine volume. RESULTS: The visual analog scale (VAS) scores in group T were lower than group C (P < 0.05). In group T, compared with T0, the R value at T1 and T2 is significantly reduced, and the K value at T1 were significantly shortened, the α-angle and MA value at T1 were significantly increased (P < 0.05). In group C, compared with T0, the R value and K value were significantly shortened, the α-angle and MA value were significantly increased at all postoperative time points (P < 0.05). Compared with group C at the same time point, the R and K values of group T were significantly longer, and the α-angle and MA values were significantly reduced at T2 and T3 points, with statistically significant differences (P<0.05). CONCLUSION: TPVB is beneficial to improve postoperative hypercoagulability and promote postoperative rehabilitation of patients after thoracoscopic lobectomy.

Effects of the nontourniquet combined with controlled hypotension technique on pain and long-term prognosis in elderly patients after total knee arthroplasty: a randomized controlled study.

PURPOSE: The aim of this study was to confirm the alleviating effects of the nontourniquet technique on the postoperative acute and chronic pain of patients after total knee arthroplasty (TKA). METHODS: 122 elderly patients undergoing TKA were randomly divided into two groups: group T (n = 58) and group H (n = 64). An electronic inflatable tourniquet was used during TKA in group T. The patients in group H received controlled hypotension but without tourniquet use during the operation. The numeric rating scale (NRS) score was used to evaluate pain level on day 1, day 2, day 3 and day 7 after the operation, and the incidence of chronic pain was judged at 3-month and 1-year follow-ups, and functional recovery of the knee joint was estimated by the active range of knee joint motion (AROM) at the same time points. Cognitive function was assessed by the montreal cognitive assessment scale (MoCA) for 7 days after operation. RESULTS: There were no significant differences in the NRS scores and AROM for 7 days after surgery. The incidence rate of chronic pain in group H (25.0%) was lower than that in group T (41.4%) and the AROM in group H was greater at one year follow-up. The MoCA score in group H was lower than that in group T on day 1 and day 2. CONCLUSION: The nontourniquet combined with controlled hypotension technique can alleviate chronic pain and promote the long-term rehabilitation of patients after TKA.

Effects of iron spin transition on the electronic structure, thermal expansivity and lattice thermal conductivity of ferropericlase: a first principles study.

The effects of the spin transition on the electronic structure, thermal expansivity and lattice thermal conductivity of ferropericlase are studied by first principles calculations at high pressures. The electronic structures indicate that ferropericlase is an insulator for high-spin and low-spin states. Combined with the quasiharmonic approximation, our calculations show that the thermal expansivity is larger in the high-spin state than in the low-spin state at ambient pressure, while the magnitude exhibits a crossover between high-spin and low-spin with increasing pressure. The calculated lattice thermal conductivity exhibits a drastic reduction upon the inclusion of ferrous iron, which is consistent with previous experimental studies. However, a subsequent enhancement in the thermal conductivity is obtained, which is associated with the spin transition. Mechanisms are discussed for the variation in thermal conductivity by the inclusion of ferrous iron and the spin transition.

The effect and safety of dexmedetomidine added to ropivacaine in brachial plexus block: A meta-analysis of randomized controlled trials.

BACKGROUND: Dexmedetomidine has been used as an adjuvanty added to local anesthetics to prolong analgesia following peripheral nerve blockade. The aim of this meta-analysis was to investigate the effect and safety of dexmedetomidine added to ropivacaine in brachial plexus block (BPB). METHODS: A search strategy was created to identify eligible randomized clinical trial (RCT) in PubMed, Embase, and The Cochrane Library (updated May, 2018). The methodologic quality for each included study was evaluated using the Cochrane Tool for Risk of Bias by 2 independent researchers. RESULTS: Twelve RCTs were included in the meta-analysis (n = 671). As an adjuvant to ropivacaine, dexmedetomidine significantly reduced the onset time of sensory (mean difference [MD], -3.86 minutes, 95% CI -5.45 to -2.27 minutes; I = 85%) and motor (MD, -5.21 minutes; 95% CI -7.48 to -2.94 minutes; I = 94%). In addition, it increased the blockade duration of sensory (MD, 228.70 minutes; 95% CI 187.87-269.52 minutes; I = 93%) and motor (MD, 191.70 minutes; 95% CI 152.48-230.91 minutes; I = 92%). Moreover, the combination prolonged the duration of analgesia (MD, 303.04 minutes; 95% CI 228.84-377.24 minutes; I = 86%). There was no difference of the incidence of bradycardia (risk difference [RD], 0.01, 95% CI -0.02 to 0.05, I = 45%; P = .45) and hypotension (RD, 0.01, 95% CI -0.01 to 0.03, I = 0%; P = .57) between 2 groups. CONCLUSION: Dexmedetomidine added to ropivacaine in BPB has a better analgesia effect (shorter onset time and longer duration) compared to ropivacaine alone. At the same time, there was no difference in the incidence of bradycardia and hypotension.

First principles study of the Mn-doping effect on the physical and chemical properties of mullite-family Al2SiO5.

Transition metal (TM) modification is a common strategy for converting an earth-abundant mineral into a cost-effective catalyst for industrial applications. Among a variety of minerals, Al2SiO5, which has three phases, andalusite, sillimanite and kyanite, is emerging as a promising candidate for new catalyst development. In this paper, we use Mn to demonstrate the rationale of 3d TM doping at the Al sites in each of these three phases through first-principles calculations and the cluster expansion method. The results of cluster expansion show that Mn has a strong site preference for the six-coordinated Al octahedral chains in the andalusite and sillimanite phases, while distributing randomly in the kyanite phase. Moreover, Mn can only replace Al in sillimanite and kyanite in low concentrations; however, higher concentrations of Mn can replace Al in andalusite. We found that the concentration sensitivity is due to the Jahn-Teller distortion and 3d orbital splitting. This finding can also explain the low doping concentrations of other 3d TMs (Fe, Cr and V) in Al2SiO5 compounds. Based on the calculated Helmholtz free energy, we constructed a (MnxAl1-x)AlSiO5 temperature-composite phase diagram, which explains the physical mechanisms behind the results for 3d transition metal doping and phase transitions in Al2SiO5. This work could shed light on the related physics, chemistry, and geoscience of (MnxAl1-x)AlSiO5, and more importantly, a design rationale for the engineering of cheap catalysts.

Effect of prophylactic dexamethasone on nausea and vomiting after laparoscopic gynecological operation: meta-analysis.

BACKGROUND: Sex of female and laraproscopic surgery are both risk factors related to postoperative nausea and vomiting, and dexamethasone is used as anti-emetic in some operations. A meta-analysis of randomized trials was performed to determine the effect of prophylactic dexamethasone administration on postoperative nausea and vomiting, pain and complications in patients undergoing laparoscopic gynecological operation. METHODS: A systematic literature search was conducted to identify all randomized clinical trials. The primary outcome was the incidence and severity of postoperative nausea and vomiting. The secondary outcomes include postoperative pain and complications. RESULTS: Totally 1801 patients were enrolled in 11 eligible randomized trials comparing effect of prophylactic dexamethasone administration on postoperative nausea and vomiting with placebo. The pooled incidence of nausea, vomiting, nausea and vomiting, and rescue anti-emetic was significantly lower in dexamethasone group than placebo group during post-anesthesia care unit (10.5% vs. 18.2%, OR 0.51, 95% CI 0.31-0.84; 6.5% vs. 17.1%, OR 0.31, 95% CI 0.17-0.56; 17.0% vs. 35.4%, OR 0.33, 95% CI 0.21-0.50; 6.7% vs. 23.3%, OR 0.22, 95% CI 0.10-0.49, P < 0.00001) and within the first postoperative 24 hours (25.2% vs. 40.3%, OR 0.46, 95% CI 0.32-0.66; 14.4% vs 36.6%, OR 0.27, 95% CI 0.19-0.40; 33.0% vs. 69.0%, OR 0.18, 95% CI 0.13-0.26; 21.0% vs 51.1%, OR 0.26, 95% CI 0.16-0.41, P < 0.00001). No significant difference was found about the incidence of rescue analgesia between dexamethasone group and placebo group (48.5% vs 56.4%, OR 0.68, 95% CI 0.40-1.18, P = 0.17). CONCLUSION: Prophylactic dexamethasone administration decreases the incidence of nausea and vomiting after laparoscopic gynecological operations during post-anesthesia care unit and within the first postoperative 24 hours. (286 words) Postoperative nausea and vomiting are the most common complications after anesthesia and surgery, and both sex of female and type of laparoscopic operation are risk factors. It is certain of a remarkably high incidence after laparoscopic gynecological surgery, which is reported as nearly 70% within the first postoperative 24 hours. It is very important to find an effective treatment to alleviate postoperative nausea and vomiting.

Asymmetric Fabry-Pérot fiber-optic pressure sensor for liquid-level measurement.

It is demonstrated that an asymmetric Fabry-Pérot fiber-optic pressure sensor is capable to precisely measure liquid levels. They are directly proportional to pressures that can modulate cavity length of Fabry-Pérot cavity. As a result, the sensor can operate over a linear region of an interference fringe that enables liquid-levels interrogation by measuring the reflected intensity. Experimental results show the resolving power of 0.4 mm, sensitivity of 2.4 mV/mm, and precision of 1 mm over range of 2.3 m (water) can be achieved. The sensor can measure liquid levels accurately, continuously, and automatically in flammable and explosive circumstances.