Search

Hypoxemia is a common complication in older patients during postoperative recovery and can cause pulmonary complications. Therefore, reducing the incidence of postoperative hypoxemia is a clinical concern.To investigate the clinical efficacy of high-flow nasal cannula oxygen (HFNCO) in the resuscitation period of older orthopedic patients.In this prospective randomized controlled trial, 60 older patients who underwent orthopedic surgery under general anesthesia were randomly divided into two groups: those who used conventional face mask and those who used HFNCO. All patients were treated with 60% oxygen for 1 h after extubation. Patients in the conventional face mask group were treated with a combination of air (2 L) and oxygen (2 L) using a traditional mask, whereas those in the HFNCO group were treated with HFNCO at a constant temperature of 34 °C and flow rate of 40 L/min. We assessed the effectiveness of oxygen therapy by monitoring the patients' arterial blood gas, peripheral oxygen saturation, and postoperative complications.The characteristics of the patients were comparable between the groups. One hour after extubation, patients in HFNCO group had a significantly higher arterial partial pressure of oxygen (paOHFNCO can improve oxygen partial pressure and respiratory function in elderly patients undergoing orthopedic surgery under general endotracheal anesthesia. Thus, HFNCO can be used to prevent postoperative hypoxemia.

Background Laparoscopic pancreaticoduodenectomy (LPD) may induce intense inflammatory response which might be related to the patient’s outcomes. Clinical dexmedetomidine (DEX) has been widely used for opioid-sparing anesthesia and satisfactory sedation. The objective of this study was to investigate the influence of DEX on inflammatory response and postoperative complications in LPD. Methods Ninety-nine patients undergoing LPD were randomly assigned to two groups: normal saline (NS) and DEX. The primary outcome was the neutrophil-to-lymphocyte ratio (NLR) differences postoperatively within 48 h. Secondary outcomes were postoperative complications, the length of postoperative hospital stay and the incidence of ICU admission. Other outcomes included anesthetics consumption and intraoperative vital signs. Results NLR at postoperative day 2 to baseline ratio decreased significantly in the DEX group (P = 0.032). Less major complications were observed in the DEX group such as pancreatic fistula, delayed gastric emptying and intra-abdominal infection (NS vs. DEX, 21.7% vs. 13.6%, P = 0.315; 10.9% vs. 2.3%, P = 0.226; 17.4% vs. 11.4%, P = 0.416, respectively) though there were no statistical differences. Three patients were transferred to the ICU after surgery in the NS group, while there was none in the DEX group (P = 0.242). The median postoperative hospital stay between groups were similar (P = 0.313). Both intraoperative propofol and opioids were less in the DEX group (P Conclusions Intraoperative DEX reduced the early postoperative inflammatory response in LPD. It also reduced the use of narcotics that may related to reduced major complications, which need additional research further.

We utilized density functional theory to systematically investigate the thermoelectric performance of two low-cost, environmentally friendly half-Heusler materials: CoNbSi and CoNbSn. It is interes...

We report a case of a severely underweight and flat chest woman with idiopathic pulmonary fibrosis who was successfully treated with cadaveric sequential bilateral lung transplantation. By the fourth months after transplantation, we found three-dimensional CT volumetry is a feasible way to evaluate postoperative thoracic cage change.

The purpose of this study was to explore the protective effect of BW373U86 (a δ-opioid receptor (DOR) agonist) on ischemia–reperfusion (I/R) injury in rat cardiomyocytes and its underlying mechanism. Primary rat cardiomyocytes were cultured and pretreated with BW373U86 for intervention. The cardiomyocytes were cultured under the condition of 94% N2 and 5% CO2 for 24 h to perform hypoxia culture and conventionally cultured for 12 h to perform reoxygenation culture. The cell viability of cardiomyocytes was detected by an MTT assay (Sigma–Aldrich). The autophagy lysosome levels in cardiomyocytes were evaluated by acidic vesicular organelles with dansylcadaverine (MDC) staining (autophagy test kit, Kaiji Biology, kgatg001). The protein expression levels of LC3, p62, and factors in the PI3K/Akt/mTOR signaling pathway were detected by Western blot. Pretreatment with BW373U86 could improve the cell viability of cardiomyocytes with hypoxia–reoxygenation (H/R) injury (p < 0.05). Interestingly, after coculture of BW373U86 and PI3K inhibitor (3-methyladenine), the protein expression levels of p-Akt in cardiomyocytes were markedly increased in comparison with those in the BW373U86 group (p < 0.05). However, there were no significant differences in the protein expression levels of mTOR between the coculture group and the BW373U86 group (p > 0.05). BW373U86 upregulated autophagy to protect cardiomyocytes from H/R injury, which may be related to the PI3K/Akt/m TOR pathway.

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury in which severe inflammatory responses induce cell apoptosis, necrosis, and fibrosis. This study investigated the role of lung adenocarcinoma transcript 1 (MALAT1) in ARDS and the underlying mechanism involved. The expression of MALAT1, microRNA-150-5p (miR-150-5p), and intercellular adhesion molecule-1 (ICAM-1) was determined in ARDS patients and lipopolysaccharide (LPS)-treated human pulmonary microvascular endothelial cells (HPMECs). Next, the interactions among MALAT1, miR-150-5p, and ICAM-1 were explored. Gain- or loss-of-function experiments in HPMECs were employed to determine cell apoptosis and inflammation. Furthermore, a mouse xenograft model of ARDS was established in order to verify the function of MALAT1 in vivo. MALAT1 and ICAM-1 were upregulated, while miR-150-5p was downregulated in both ARDS patients and LPS-treated HPMECs. MALAT1 upregulated ICAM-1 expression by competitively binding to miR-150-5p. MALAT1 silencing or miR-150-5p overexpression was shown to suppress HPMEC apoptosis, decrease the expressions of pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) and E-selectin in HPMECs, as well as alleviated lung injury in nude mice. These findings demonstrated that MALAT1 silencing can potentially suppress HPMEC apoptosis and alleviate lung injury in ARDS via miR-150-5p-targeted ICAM-1, suggestive of a novel therapeutic target for ARDS.

The point of departure for the particle-based discrete element simulations is the generation of disk or sphere packing of interest domain. In this paper, based on a triangular mesh, two geometric packing algorithms are proposed for 2D problems. New disk(s) are obtained element-wise by solving system of equations, which can be easily derived according to the local topological relationships. In this way, the adjacent disks are guaranteed to be in contact with each other exactly. Related issues are discussed in detail, such as boundary treatment for good definition of the boundaries, elimination of incorrect overlaps, random perturbation for avoiding over-homogeneous packing. The main advantages of these two algorithms are the high efficiency and applicability for arbitrary domains. Furthermore, with a refined mesh, a refined packing can be easily obtained, which is a potential alternative for multiscale simulations. The proposed methods are verified by several examples.

Parameter selection is always a critical issue for the numerical modeling of many geotechnical problems. In this work, an idea of non-parameterized numerical analysis is demonstrated by incorporating tri-axial data as the input into the distinct lattice spring model (DLSM). An automatic parameter acquisition procedure is developed to determine the parameters of a modified Duncan–Chang (DC) model which is implemented in the DLSM through the further development of an incremental DLSM and a fabric stress calculation scheme. These newly developed algorithms are verified against available numerical results and experimental counterparts. Then, the discrete feature of the DC-DLSM is explored and discussed through the numerical modeling of large-scale tri-axial tests and a fracturing test. Finally, a real rockfill dam project is analyzed by using the DC-DLSM with the available tri-axial data as the input, and a reasonable fitting is obtained, which shows the possibility for the numerical modeling of the DLSM with no parameter selection burden.

Increasing evidence suggested that inhibiting the apoptosis of Schwann cells (SCs) and promoting nerve growth factor (NGF) expression in sciatic nerves play key roles in preventing the onset of diabetic peripheral neuropathy (DPN). Curcumin, a primary bioactive substance in turmeric with multiple characteristics, has been shown to have many therapeutic effects in a variety of diseases. However, curcumin is poorly studied in the DPN models. We aimed to explore the therapeutic benefits and underlying mechanism of curcumin in high fat/sugar diets joint streptozotocin (STZ)-induced DPN rat models. Sprague-Dawley (SD) rats were divided into five groups (6 rats per group), control group, DPN group, Curcumin groups (50, 100, and 150 mg/kg). Curcumin was administered intragastrically once per day for 4 continuous weeks. Body weight (BW) and fasting blood glucose (FBG) were monitored in all groups. The mechanical withdraw threshold (MWT) was measured. We also assessed neuropathic change by testing nerve conductance velocity (NCV) in sciatic nerves. TEM was applied to observe the sciatic nerves ultrastructure. The SCs apoptosis in sciatic nerves was stained using TUNEL kit. NGF contents in sciatic nerves and serum were detected using western blotting and ELISA analysis. The results showed curcumin had no obvious effect on the BW and FBG change. Curcumin (100 and 150 mg/kg) attenuated the MWT, NCV, and sciatic nerves ultrastructure in DPN rats. Curcumin (50, 100 and 150 mg/kg) reduced SCs apoptosis in sciatic nerves. In addition, curcumin at 150 mg/kg had the best efficacy in increasing protein expression of NGF in sciatic nerves and serum NGF level. Our work demonstrated that curcumin has neuroprotective effects for the treatment of DPN.

Spinal anesthesia is superior to general anesthesia for postoperative recovery in older patients (≥ 65 age). However, evidence for this is lacking.To evaluate the effect of anesthesia on postoperative complications in older patients undergoing hip surgery.This is a retrospective, propensity score-matched, cohort study. Patients ≥ 65-years-old who underwent hip surgery at the Traditional Chinese Medicine of Guangdong Provincial Hospital in China from October 2016 to June 2020 were included. The operative methods were femoral fracture's internal fixation and hip replacement. The orthopedic doctors in different hospitals of our group have varied requirements for patients' out-of-bed time after surgery. Therefore, spinal anesthesia or general anesthesia was selected according to the requirements of the orthopedic doctors. The primary outcome of this study was complications during the hospitalization of the postoperative patient. The length of hospital stay, postoperative blood transfusion, routine blood analysis, renal function, coagulation function, and inflammatory correlations were secondary outcomes. Propensity score matching (PSM) was performed utilizing logistic regression.Among the 864 patients identified from the electronic medical record data database, we screened out those with incomplete medical record data. After PSM of the baseline values of the two groups of patients, data of 309 patients (206 patients in spinal anesthesia group and 103 patients in general anesthesia) were utilized in this study. 67/309 patients had complications, including postoperative limb dysfunction, pulmonary infection, delirium, lower extremity venous thrombosis, and shock. The incidence of complications was not related to anesthesia methods (Anesthesia technology is not a risk factor for postoperative complications of hip surgery. The levels of D-Dimer and hsCRP were higher in the spinal anesthesia group.

Digital image correlation (DIC) is used to investigate crack initiation and propagation in discs of transversely isotropic Hawkesbury sandstone subjected to the Brazilian test . To verify DIC's validity and precision a simple calibration method is presented. It involves adjusting the size and spacing of subsets of pixels within images of a specimen's surface from which local deformations and strains are quantified, achieving agreement between strains measured by DIC and gauges attached to the surface. Using DIC the tensile and shear strain fields, crack opening displacements (CODs) and displacement vectors are determined at all stages of loading. The development of the fracture process zone is also identified prior to a major crack initiation. Also, a range of load contact configurations is considered, including the loads being applied via flat rigid platens and across finite strips with widths controlled by small (3 mm wide) and big (5 mm wide) wooden cushions placed between the load applicators and discs. It is observed that, for 0° and 90° anisotropy angles (representing layering normal to and parallel to diameters connecting load contacts) and for both the flat platen and small wooden cushion, cracks initiate far from the disc centres. Also, for the 45° anisotropy angle and all load configurations, cracks initiate at the disc centres. Furthermore, when the loads are applied via big wooden cushions, cracks initiate at the disc centres regardless of the anisotropy angle. Also, specimens loaded via big wood cushions exhibited the largest COD while the specimens loaded via small wood cushions exhibited the smallest. Also, specimens loaded via flat platens failed at smaller loads compared to those using wooden cushions. This study confirms transverse isotropy has strong effect on crack development. It also demonstrates important parameters including time and location of initiation, as well as COD, may be determined using DIC.

Currently, exosome-enclosed microRNAs (miRs) in exhaled breath have potential for biomarker discovery in patients with pulmonary diseases. This study was performed to investigate the roles of M2 macrophage-derived exosomes expressing miR-328 in pulmonary fibrosis (PF). Microarray-based analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs in PF. The miR-target relationship between FAM13A and miR-328 was confirmed. The expression of FAM13A and miR-328 was measured in PF rats, and gain- and loss-of-function assays were conducted to determine the regulatory effects of FAM13A and miR-328 on PF. In addition, exosomes derived from M2 macrophages were isolated and then cocultured with pulmonary interstitial fibroblasts to identify the role of these exosomes in PF. Furthermore, the effects of M2 macrophage-derived exosomes overexpressing miR-328 on pulmonary fibroblast proliferation and the progression of PF were assessed in vivo. miR-328 might perform a vital function in PF by regulating FAM13A. FAM13A expression was downregulated while miR-328 expression was upregulated in rats with PF, and a miR-target relationship between miR-328 and FAM13A was observed. Additionally, miR-328 overexpression and FAM13A silencing each were suggested to promote pulmonary interstitial fibroblast proliferation and the expression of Collagen 1A, Collagen 3A and α-SMA. Then, in vitro experiments demonstrated that M2 macrophage-derived exosomes overexpressing miR-328 contributed to enhanced pulmonary interstitial fibroblast proliferation and promoted PF. Furthermore, in vivo experiments confirmed the promotive effects of M2 macrophage-derived exosomes overexpressing miR-328 on the progression of PF. Collectively, the results showed that M2 macrophage-derived exosomes overexpressing miR-328 aggravate PF through the regulation of FAM13A., Lung disease: Small RNAs promoting pulmonary fibrosis Studies in rats suggest that microRNAs, small molecules of ribonucleic acid, released by macrophage cells of the immune system can promote pulmonary fibrosis (PF), the formation of scar tissue in lungs. Gao-Feng Zhao, Li-Hua Xing and colleagues at The First Affiliated Hospital of Zhengzhou University in China investigated the role of microRNAs in rats with a form of PF that serves as a model for the disease in humans. Their findings confirm that specific microRNAs released in tiny membrane-bound sacs called exosomes interact with and inhibit a gene whose activity is known to be disrupted in PF. The protein encoded by this gene mediates crucial molecular signaling events in lung cells. Developing drugs that interfere with the activity of the microRNAs is a potential new treatment approach for PF.

In this work, the distinct lattice spring model (DLSM) and the lattice Boltzmann method (LBM) are coupled together to simulate hydraulic fracturing problems. As the DLSM and LBM are both lattice modelling methods, the lattice meshes in these two systems are simply overlapped, which results in the same resolution in both the DLSM and LBM. The momentum exchange bounce-back algorithm is used to evaluate the forces exerted on the solid particles. Moreover, the calculation step in the LBM and DLSM is synchronised for prompt updates of fluid–solid interactions. The coupled model is further validated through a series of benchmarks. Finally, the coupled model shows its ability to simulate hydraulic fracturing in formations with complex discrete fracture networks.

In this work, a general framework is developed for the incorporation of elasto-plastic constitutive models into the Distinct Lattice Spring Model (DLSM). Within this framework, a smoothed non-associative Drucker-Prager (DP) model is implemented. To verify the model, a number of numerical examples are examined, and the results are compared to the analytical solution, numerical solution based on the Finite Volume Method (FVM), and the experimental results, where available. It is shown that the proposed framework is numerically stable and is capable of solving elasto-plastic problems while maintaining the general advantages of the LSM technique in tacking material fracturing.

A fundamental study on the tensile failure of rock is conducted using the three-dimensional lattice spring model. The model covers three aspects: (1) the relationship between the mesoscopic tensile/shear failure and the corresponding macroscopic tensile failure; (2) the effects of the size, shape, and location of the initial defect on the macroscopic tensile failure; and (3) the effects of the porosity, heterogeneity, crystal structure, mesoscopic constitutive model, and model scale on its macroscopic tensile responses. Through investigation, this study reveals that the mesoscopic strength heterogeneity affects the macroscopic pre-peak response of rock, and the initial defect could control its macroscopic post-peak response. The post-peak characteristics of the mesoscopic constitutive model influence both the macroscopic pre-peak and post-peak responses, which are scale independent and scale dependent, respectively. Based on these investigations, a parameter-selection method for the mesoscopic constitutive model is established to fully utilize the macroscopic tensile experimental data.

This paper studies the propagation and attenuation of blasting wave induced by explosion in underground rock cavern by employing the newly developed four-dimensional lattice spring model (4D-LSM). The non-reflection viscous boundary condition was implemented in the 4D-LSM to reduce the computing resources of full-scale simulation of blasting wave propagation in the practical engineering. Then, a number of damping models were developed and implemented in the 4D-LSM to describe the attenuation of blasting wave in the rock mass. In addition, the influence of the loading form of blast load and damping models on the propagation and attenuation of blasting wave were studied by comparing with the field test data in details. It was found that the loading form of a triangular blast stress wave with an equivalent pressure wave and the coupled damping model could lead the 4D-LSM producing a reasonable fitting over the field test data in terms of both the blasting waveform recorded at a given measuring point and attenuation results from a number of measuring points. Our study provides a basis for the further application of the 4D-LSM as an alternative numerical tool in modeling the blasting wave propagation problems in rock engineering.

Recently, a four-dimensional lattice spring model (4D-LSM) was developed to overcome the Poisson's ratio limitation of the classical LSM by introducing the fourth-dimensional spatial interaction. In this work, some aspects of the 4D-LSM on solving problems in geomechanics are investigated, such as the ability to reproduce elastic properties of geomaterials, the capability of solving heterogeneous problems, the accuracy on modelling stress wave propagation, the ability to solve dynamic fracturing and the parallel computational efficiency. Our results indicate that the 4D-LSM is promising to deal with problems in geomechanics.

The spontaneous crack growth in an infinite domain is studied using the distinct lattice spring model (DLSM). The kinetic energy, strain energy, crack opening, and crack branching during the crack growth are investigated numerically using a simple spring model. The discrete simulation satisfactorily reproduces the experimental observations and the theoretical predictions of the fracture energy increase even without considering the crack tip damage zone and crack bifurcation. Moreover, from analysis of the intrinsic fracture energy release rate, it was concluded that the observed fracture energy increase should originate from the distribution of kinetic energy during self-similar crack growth.