Copyrolysis of Waste Cartons and Polyolefin Plastics under Microwave Heating and Characterization of the Products.

Municipal organic solid waste contains many recoverable resources, including biomass materials and plastics. The high oxygen content and strong acidity of bio-oil limit its application in the energy field, and the oil quality is mainly improved by copyrolysis of biomass with plastics. Therefore, in this paper, a copyrolysis method was utilized to treat solid waste, namely, common waste cartons and waste plastic bottles (polypropylene (PP) and polyethylene (PE)) as raw materials. The products were analyzed by Fourier transform infrared (FT-IR) spectroscopy, elemental analysis, GC, and GC/MS to investigate the reaction pattern of the copyrolysis. The results show that the addition of plastics can reduce the residue content by about 3%, and the copyrolysis at 450 °C can increase the liquid yield by 3.78%. Compared with single waste carton pyrolysis, no new product appeared in the copyrolysis liquid products but the oxygen content of the liquid decreased from 65% to less than 8%. The content of CO2 and CO in the copyrolysis gas product is 5-15% higher than the theoretical value; the O content of the solid products increased by about 5%. This indicates that waste plastics can promote the formation of l-glucose and small molecules aldehydes and ketones by providing H radicals and reduce the oxygen content in liquids. Thus, copyrolysis improves the reaction depth and product quality of waste cartons, which provides a certain theoretical reference for the industrial application of solid waste copyrolysis.

Microglial voltage-dependent anion channel 1 signaling modulates sleep deprivation-induced transition to chronic postsurgical pain.

STUDY OBJECTIVES: This study verified that sleep deprivation before and after skin/muscle incision and retraction (SMIR) surgery increased the risk of chronic pain and investigated the underlying roles of microglial voltage-dependent anion channel 1 (VDAC1) signaling. METHODS: Adult mice received 6 hours of total sleep deprivation from 1 day prior to SMIR until the third day after surgery. Mechanical and heat-evoked pain was assessed before and within 21 days after surgery. Microglial activation and changes in VDAC1 expression and oligomerization were measured. Minocycline was injected to observe the effects of inhibiting microglial activation on pain maintenance. The VDAC1 inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) and oligomerization inhibitor VBIT-4 were used to determine the roles of VDAC1 signaling on microglial adenosine 5' triphosphate (ATP) release, inflammation (IL-1ß and CCL2), and chronicity of pain. RESULTS: Sleep deprivation significantly increased the pain duration after SMIR surgery, activated microglia, and enhanced VDAC1 signaling in the spinal cord. Minocycline inhibited microglial activation and alleviated sleep deprivation-induced pain maintenance. Lipopolysaccharide (LPS)-induced microglial activation was accompanied by increased VDAC1 expression and oligomerization, and more VDAC1 was observed on the cell membrane surface compared with control. DIDS and VBIT-4 rescued LPS-induced microglial ATP release and IL-1ß and CCL2 expression. DIDS and VBIT-4 reversed sleep loss-induced microglial activation and pain chronicity in mice, similar to the effects of minocycline. No synergistic effects were found for minocycline plus VBIT-4 or DIDS. CONCLUSIONS: Perioperative sleep deprivation activated spinal microglia and increases the risk of chronic postsurgical pain in mice. VDAC1 signaling regulates microglial activation-related ATP release, inflammation, and chronicity of pain.

Initial stage of carbonization of iron during hydrocarbons dissociation: a molecular dynamics study.

The carbonization of iron is a very important early phenomenon in the field of heterogeneous catalysis and the petrochemical industry, but the mechanism is still controversial. In this work, the carbonization mechanism and carbonization structure of iron nanoparticles by different carbon sources (CH4, C2H6, C2H4, C2H2) were systematically investigated using the reactive molecular dynamics method. The results show that saturated alkanes are dehydrogenated while adsorbed, but unsaturated olefins and alkynes undergo bond-breaking while adsorbed. The C-H bond is more likely to break than the C-C bond. Hydrocarbons with high carbon content have a strong ability to carbonize Fe nanoparticles under the same conditions. For C2H4 and C2H2, the C atoms generated from dissociation form a large number of long carbon chains intertwined with branched chains and multiple carbon rings. The C2 species formed by C2H2 after complete dehydrogenation diffuse rapidly to the interior of the nanoparticles, releasing the surface active sites and accelerating the carbonization process. Carbon-rich iron carbides (FeCx) with different Fe/C ratios were obtained by carbonization with different carbon sources. In addition, the Fe(110) surface exhibits the strongest carburizing ability. These findings provide systematic insights into the initial stages of metal Fe carburization.

Mechanically Activated Calcium Channel PIEZO1 Modulates Radiation-Induced Epithelial-Mesenchymal Transition by Forming a Positive Feedback With TGF-ß1.

TGF-ß-centered epithelial-mesenchymal transition (EMT) is a key process involved in radiation-induced pulmonary injury (RIPI) and pulmonary fibrosis. PIEZO1, a mechanosensitive calcium channel, is expressed in myeloid cell and has been found to play an important role in bleomycin-induced pulmonary fibrosis. Whether PIEZO1 is related with radiation-induced EMT remains elusive. Herein, we found that PIEZO1 is functional in rat primary type II epithelial cells and RLE-6TN cells. After irradiation, PIEZO1 expression was increased in rat lung alveolar type II epithelial cells and RLE-6TN cell line, which was accompanied with EMT changes evidenced by increased TGF-ß1, N-cadherin, Vimentin, Fibronectin, and α-SMA expression and decreased E-cadherin expression. Addition of exogenous TGF-ß1 further enhanced these phenomena in vitro. Knockdown of PIEZO1 partly reverses radiation-induced EMT in vitro. Mechanistically, we found that activation of PIEZO1 could upregulate TGF-ß1 expression and promote EMT through Ca2+/HIF-1α signaling. Knockdown of HIF-1α partly reverses enhanced TGF-ß1 expression caused by radiation. Meanwhile, the expression of PIEZO1 was up-regulated after TGF-ß1 co-culture, and the mechanism could be traced to the inhibition of transcription factor C/EBPß expression by TGF-ß1. Irradiation also caused a decrease in C/EBPß expression in RLE-6TN cells. Dual luciferase reporter assay and chromatin immunoprecipitation assay (ChIP) confirmed that C/EBPß represses PIEZO1 expression by binding to the PIEZO1 promoter. Furthermore, overexpression of C/EBPß by using the synonymous mutation to C/EBPß siRNA could reverse siRNA-induced upregulation of PIEZO1. In summary, our research suggests a critical role of PIEZO1 signaling in radiation-induced EMT by forming positive feedback with TGF-ß1.

PIEZO1 Ion Channel Mediates Ionizing Radiation-Induced Pulmonary Endothelial Cell Ferroptosis via Ca2+/Calpain/VE-Cadherin Signaling.

Pulmonary endothelial cell dysfunction plays an important role in ionizing radiation (IR)-induced lung injury. Whether pulmonary endothelial cell ferroptosis occurs after IR and what are the underlying mechanisms remain elusive. Here, we demonstrate that 15-Gy IR induced ferroptosis characterized by lethal accumulation of reactive oxygen species (ROS), lipid peroxidation, mitochondria shrinkage, and decreased glutathione peroxidase 4 (GPX4) and SLC7A11 expression in pulmonary endothelial cells. The phenomena could be mimicked by Yoda1, a specific activator of mechanosensitive calcium channel PIEZO1. PIEZO1 protein expression was upregulated by IR in vivo and in vitro. The increased PIEZO1 expression after IR was accompanied with increased calcium influx and increased calpain activity. The effects of radiation on lung endothelial cell ferroptosis was partly reversed by inhibition of PIEZO1 activity using the selective inhibitor GsMTx4 or inhibition of downstreaming Ca2+/calpain signaling using PD151746. Both IR and activation of PIEZO1 led to increased degradation of VE-cadherin, while PD151746 blocked these effects. VE-cadherin knockdown by specific siRNA causes ferroptosis-like phenomena with increased ROS and lipid peroxidation in the lung endothelial cells. Overexpression of VE-cadherin partly recused the ferroptosis caused by IR or PIEZO1 activation as supported by decreased ROS production, lipid peroxidation and mitochondria shrinkage compared to IR or PIEZO1 activation alone. In summary, our study reveals a previously unrecognized role of PIEZO1 in modulating ferroptosis, providing a new target for future mitigation of radiation-induced lung injury.

Insight into the magnetic moment of iron borides: theoretical consideration from the local coordinative and electronic environment.

Experimentally observed magnetic properties are usually statistically averaged from bulk materials and information associated with the local chemical environment cannot be specified. Against this backdrop, we propose a theoretical strategy to provide an in-depth understanding of the multi-role for metrics that may contribute to the apparent magnetic moment of iron borides. In particular, we demonstrate this strategy through systematic manipulation of the iron/boron stoichiometry of six prototype iron borides to tune their associated local structural and electronic environment to further modulate the resultant magnetic moment. The local coordinative structures of the six iron borides were resolved utilizing bond valence analysis by taking the different coordination shells into account. Furthermore, the local electronic properties of each Fe atom in these iron borides, such as charge transfer, electronic distribution, bonding feature and orbital energy level, were carefully analyzed by Bader analysis, density of states analysis and Crystal Orbital Hamilton Population analysis. From the combination of analyses of both the coordinative and electronic properties of the prototype iron borides, a linear relationship between the local magnetic moment and the bond valence as well as the average energy of the Fe 3d orbitals has been confirmed.

Promoting sleep and circadian health may prevent postoperative delirium: A systematic review and meta-analysis of randomized clinical trials.

This systematic review with meta-analysis and trial sequential analysis of randomized clinical trials aimed to clarify the efficacy of sleep and circadian interventions on preventing postoperative delirium. The search and screening identified 13 trials with great heterogeneity in interventions, surgery types as well as methods for evaluating delirium, sleep and circadian rhythms. Meta-analyses revealed that sleep and circadian interventions were associated with decreased incidences of postoperative delirium (pooled relative risk (RR) = 0.48, 95% confidence interval (CI) = 0.29 to 0.78) compared with control. The pooled incidences of delirium for patients receiving interventions and no intervention (control) were 8.6% and 20.7% respectively. Results of the trial sequential analysis supported the interpretation that sleep and circadian interventions significantly diminished delirium compared to control. Subgroup analysis found that interventions that showed positive efficacy on sleep and circadian outcomes (p < 0.001), but not those without improvements (p = 0.114) or without assessments (p = 0.858), were associated with decreased risk of delirium. Dexmedetomidine sedation (p < 0.001) and timed bright light exposure (p = 0.006) appeared to reduce postoperative delirium. In summary, currently only limited evidence suggests strategies targeted at sleep and circadian health as a useful way to prevent postoperative delirium.

Piezo1 mediates neuron oxygen-glucose deprivation/reoxygenation injury via Ca2+/calpain signaling.

OBJECTIVE: We investigated whether Piezo1 could regulate oxygen-glucose deprivation/reoxygenation injury of neurons through Ca2+/calpain signaling. METHODS: Piezo1 expression in rat brain cortex and PC12 cells were confirmed by immunohistochemistry, immunofluorescence and Western blotting. The effects of Yoda1 and GsMTx4 on OGD/R-induced decrease in cell viability, increase in cell apoptosis and activation of downstreaming Ca2+/calpain signaling were investigated. Furthermore, calpain signaling was inhibited by PD151746 to see whether Ca2+/calpain signaling participated in the neurotoxic effects of Piezo1 activation. RESULTS: Piezo1 expression was increased in rat cerebral cortex after ischemia/reperfusion and in PC12 cells after OGD/R. Activation of Piezo1 by Yoda1 enhanced OGD/R-induced cell viability inhibition, apoptosis, increase intracellular calcium levels and enhanced calpain activity while GsMTx4 showed the opposite effects. The effects of Piezo1 activation on cell viability and apoptosis were reversed by PD151746. CONCLUSION: Piezo1 could regulate neuron oxygen-glucose deprivation/reoxygenation injury via activation of Ca2+/calpain signaling.

Prazosin inhibits the growth and mobility of osteosarcoma cells.

BACKGROUND: Osteosarcoma is a primary malignant bone tumor that frequently occurs in adolescents and children, its high aggressiveness and rapid metastasis often resulting in poor prognoses. In previous studies, Prazosin has been shown to possess anti-proliferative properties against prostate cancer and glioblastoma cells. In our study, we investigated Prazosin's underlying mechanisms and its effects on the biological behaviors of osteosarcoma cells. METHODS: Osteosarcoma cell lines MG63 and 143B were treated with different concentrations of Prazosin, and a CCK8 assay assessed its effect on cell viability. Colony formation, Transwell and flow cytometry assays were used to examine its effects on cell proliferation, cell migration, and cell invasion and apoptosis, respectively. The expression of relevant proteins was then examined using western blotting. RESULTS: Our data showed that Prazosin dose-dependently reduced the viability of MG63 and 143B cells and significantly inhibited their clonogenic ability. Moreover, Prazosin attenuated the cell migration and invasion abilities of MG63 and 143B cells when compared with the NC group. It also accelerated cell apoptosis in mitochondrial pathways by regulating Bcl-2/Bax axis and caspase 3. Furthermore, Prazosin treatment inactivated the Akt/mTOR pathway by down-regulating Akt and mTOR phosphorylation (p-Akt, p-mTOR) and the expression of P70 and cyclin D1. CONCLUSIONS: Our data highlights the fact that Prazosin inhibits cell growth, inhibits the motility of osteosarcoma cells, and promotes apoptosis, suggesting that Prazosin is a potential anti-cancer agent in osteosarcoma therapy.

Development of a reactive force field for the Fe-C interaction to investigate the carburization of iron.

The approach of molecular dynamics with Reactive Force Field (ReaxFF) is a promising way to investigate the carburization of iron which is pivotal in the preparation of desired iron-based materials and catalysts. However, it is a challenge to develop a reliable ReaxFF to describe the Fe-C interaction, especially when it involves bond rearrangement. In this work, we develop an exclusive set of Reactive Force Field (ReaxFF) parameters, denoted RPOIC-2017, to describe the diffusion behavior of carbon atoms in the α-Fe system. It inherited some partial parameters in 2012 (ReaxFF-2012) which are suitable for hydrogen adsorption and dissociation. This set of parameters is trained against data from first-principles calculations, including the equations of state of α-Fe, the crystal constant of Fe3C and Fe4C, a variety of periodic surface structures with varying carbon coverages, as well as the barriers of carbon diffusion in the α-Fe bulk and on diverse surfaces. The success in predicting the carbon diffusion coefficient and the diffusion barrier using the developed RPOIC-2017 potential demonstrates that the performance is superior to that of the traditional MEAM potential. The new ReaxFF for the Fe-C interaction developed in this work is not only essential for the design of novel iron based materials, but could also help understand atomic arrangements and the interfacial structure of iron carbides.

How far away are iron carbide clusters from the bulk?

Combining the basin hopping structure searching algorithm and density functional theory, the iron carbide clusters, FexCy (x ≤ 8 and y ≤ 8), and clusters with various stoichiometries (Fe2nCn, Fe3nCn, FenC2n, FenC3n and FenC4n (n = 1-7), Fe5nC2n, and Fe4nCn (n = 1-5)) are predicted. The stable structures of iron rich carbide clusters are composed of C-C dimers or single C atoms on the surface of the clusters, which are remarkably different from their corresponding bulk structures, where the carbon atoms are atomically distributed in the iron matrix. The most stable carbon rich clusters are highly diverse in topology (bowl, basket, plane, shoe, necklace, etc.) with long carbon chains. The Bader charge analysis shows that the size effect on iron carbide clusters is an electronic tuning. Large carbon-rich clusters appear even under low carbon chemical potentials, whereas small iron-rich clusters are only energetically stable in high carbon chemical potentials, which indicates that changing the carbon chemical potential can tune the morphology (size and stoichiometry) of the iron carbide clusters. These results may help us understand the catalytic activity of iron and iron carbides in reactions such as the Fischer-Tropsch synthesis and the carbon nanotube formation process.

Mössbauer Spectroscopy of Iron Carbides: From Prediction to Experimental Confirmation.

The Mössbauer spectroscopy of iron carbides (α-Fe, γ'-FeC, η-Fe2C, ζ-Fe2C, χ-Fe5C2, h-Fe7C3, θ-Fe3C, o-Fe7C3, γ'-Fe4C, γ''-Fe4C, and α'-Fe16C2) is predicted utilizing the all electron full-potential linearized augmented plane wave (FLAPW) approach across various functionals from LDA to GGA (PBE, PBEsol, and GGA + U) to meta-GGA to hybrid functionals. To validate the predicted MES from different functionals, the single-phase χ-Fe5C2 and θ-Fe3C are synthesized in experiment and their experimental MES under different temperature (from 13 K to 298 K) are determined. The result indicates that the GGA functional (especially, the PBEsol) shows remarkable success on the prediction of Mössbauer spectroscopy of α-Fe, χ-Fe5C2 and θ-Fe3C with delocalized d electrons. From the reliable simulations, we propose a linear relationship between Bhf and µB with a slope of 12.81 T/µB for iron carbide systems and that the proportionality constant may vary from structure to structure.

Adding dexmedetomidine to ropivacaine for lumbar plexus and sciatic nerve block for amputation of lower limb in high-risk patient-a case report.

The ischemia necrosis of limb frequently requires surgery of amputation. Lumbar plexus and sciatic nerve block is an ideal intra-operative anesthetic and post-operative antalgic technique for patients of amputation, especially for high-risk patients who have severe cardio-cerebrovascular diseases. However, the duration of analgesia of peripheral nerve block is hardly sufficient to avoid the postoperative pain and the usage of opioids. In this case, a 79-year-old man, with multiple cerebral infarcts, congestive heart failure, atrial flutter and syncope, was treated with an above knee amputation because of ischemia necrosis of his left lower limb. Dexmedetomidine 1 µg/kg was added to 0.33% ropivacaine for lumbar plexus and sciatic nerve block in this case for intra-operative anesthesia and post-operative analgesia. The sensory function was blocked fully for surgery and the duration of analgesia maintained 26 hours with haemodynamic stability and moderate sedation. The patient did not complain pain and require any supplementary analgesics after surgery. This case showed that adding 1 µg/kg dexmedetomidine to ropivacaine for lumbar plexus and sciatic nerve block may be a feasible and safe technique for high-risk patients for lower limb surgery of amputation.

Anesthesia for stem cell transplantation in autistic children: A prospective, randomized, double-blind comparison of propofol and etomidate following sevoflurane inhalation.

The objective of the present study was to comparatively investigate the feasibility and safety of etomidate and propofol use following sevoflurane inhalation in autistic children during the intrathecal transplantation of stem cells. The patients selected were 60 autistic children with American Society of Anesthesiologists physical status I, who were aged between two and 12 years and scheduled for stem cell transplantation. The children received an inhalation induction of 8% sevoflurane, followed by intravenous injection of etomidate (0.2 mg/kg) in group E and propofol (2 mg/kg) in group P (n=30/group). Supplemental doses of 0.1 mg/kg etomidate or 1 mg/kg propofol were used until a deep sedation was obtained. The heart rate (HR), mean arterial pressure, oxygen saturation, respiratory rate, Ramsay sedation score (RSS) and recovery time were monitored continuously. Following anesthesia, blood pressure and HR measurements were significantly decreased in group P compared with the baseline (P<0.01) and group E values at the same time-points (P<0.05). The occurrence of adverse effects, such as respiratory depression, bradycardia, hypotension and pain on injection, was significantly higher in group P than that in group E, whereas the incidence of myoclonus in group E was significantly higher than that in group P (P<0.01). No significant differences in anesthesia induction, surgery duration, recovery time, RSS and physician satisfaction were observed between the two groups. In conclusion, sevoflurane-etomidate combinations resulted in more stable hemodynamic responses and relatively fewer adverse effects compared with propofol injection following sevoflurane inhalation and may therefore be more suitable for the induction of short-term anesthesia in autistic children during stem cell transplantation.

Etomidate with or without flumazenil anesthesia for stem cell transplantation in autistic children.

BACKGROUND: The aim of this study was to investigate etomidate administration with or without flumazenil in autistic children who underwent intrathecal transplantation of stem cells by lumbar puncture. METHODS: Forty autistic children aged 2-12, who were scheduled for stem cell transplantation via lumbar puncture under anesthesia, were randomized for a double-blind study. The children were randomly assigned to two groups: the flumazenil group (group F, n=20) and the etomidate group (group E, n=20). All children received 0.2 mg/kg of etomidate. In the case of inadequate anesthesia, patients received repeated doses of 0.1 mg/kg of etomidate until reaching deep sedation. After operation, children in group F were given flumazenil (0.01 mg/kg) and children in group E received placebo. Heart rate (HR), mean arterial pressure, oxygen saturation, respiratory rate, the Ramsay sedation score (RSS), and recovery time of all children were continuously monitored and recorded during the entire procedure. RESULTS: After anesthesia, blood pressure and HR measurements were not significantly changed in both groups compared with the baseline. There were no respiratory depression, bradycardia, hypotension, nausea, and vomiting. Five patients complained of pain on the site of injection. Myoclonus occurred in seven patients. Recovery time in group F was significantly shorter than in group E (p<0.001), and after the injection of flumazenil, RSS in group F significantly decreased than in group E. There were no significant differences in operation time. Physician satisfaction in both groups was similar. CONCLUSIONS: Etomidate resulted in stable hemodynamic responses and relatively less adverse effects, and flumazenil antagonized the anesthetic effect of etomidate; thus, etomidate with flumazenil is suitable for performing stem cell transplantation in autistic children.

Insight into CH(4) formation in iron-catalyzed Fischer-Tropsch synthesis.

Spin-polarized density functional theory calculations have been performed to investigate the carbon pathways and hydrogenation mechanism for CH(4) formation on Fe(2)C(011), Fe(5)C(2)(010), Fe(3)C(001), and Fe(4)C(100). We find that the surface C atom occupied sites are more active toward CH(4) formation. In Fischer-Tropsch synthesis (FTS), CO direct dissociation is very difficult on perfect Fe(x)C(y) surfaces, while surface C atom hydrogenation could occur easily. With the formation of vacancy sites by C atoms escaping from the Fe(x)C(y) surface, the CO dissociation barrier decreases largely. As a consequence, the active carburized surface is maintained. Based on the calculated reaction energies and effective barriers, CH(4) formation is more favorable on Fe(5)C(2)(010) and Fe(2)C(011), while Fe(4)C(100) and Fe(3)C(001) are inactive toward CH(4) formation. More importantly, it is revealed that the reaction energy and effective barrier of CH(4) formation have a linear relationship with the charge of the surface C atom and the d-band center of the surface, respectively. On the basis of these correlations, one can predict the reactivity of all active surfaces by analyzing their surface properties and further give guides for catalyst design in FTS.

[Toll-like receptor 4 signal pathway may be involved in cerebral ischemic tolerance induced by hypoxic preconditioning: experiment with rats].

OBJECTIVE: To investigate the role of Toll-like receptor 4 (TLR4) inflammatory signal pathway in brain ischemic tolerance induced by hypoxia preconditioning (HP). METHODS: 160 Wistar rats were randomly divided into 4 groups: asphyxial cardiac arrest (ACA) group (n = 54, subjected to ACA for 4 min and then resuscitation), HP + ACA group [n = 44, subjected to apnea and ventilation (HP) for 1 min 4 times with an interval of 5 min between each 2 times, and then subjected to apnea for 4 min and resuscitation 24 h later), HP group (n = 42, subjected to HP 4 times only), and sham operation group (Group C, n = 20). The mortality within 24 h after resuscitation and circulatory functions were observed. Neurodeficit score (NDS) was recorded 24, 48, and 72 hours after successful resuscitation. Rats were killed 1, 3, 6, 12, 24, 48, and 72 h after preconditioning or operation to take out the left brain cortex. RT-PCR was used to detect the mRNA expression of TLR4. The levels of nuclear factor-kappaB (NFkappaB), tumor necrosis factor-alpha (TNF-alpha), and interleukin (IL)-6 were detected by relevant kits. RESULTS: The mortality of the HP + ACA group was 5%, significantly lower than that of ACA group (30%, P < 0.01). The NDS levels at different time points of the HP group and Group C were all 100 +/- 0. The NDS levels of the HP + ACA group and ACA group at different time points were all significantly lower than those of the control group and HP group (all P < 0.01). The NDS levels at different time points of the ACA group were all significantly lower than those of the HP + ACA group (all P < 0.05). The NDS levels 72 h later of the HP + ACA and ACA groups were both significantly higher than those 24 h later of the corresponding groups (both P < 0.05). The TLR4 mRNA expression of the control group at any time points were all very weak, and the TLR4 mRNA expression level of the other groups increased since 1 h after hypoxia gradually and decreased 72 h later. The NFkappaB expression levels of the control group at any time points were all very weak, and the NFkappaB expression level of the other groups increased time-dependently since 1 h later, peaked 3 - 6 h later, and began to decrease 24 h later. There was a tendency of increase of NFkappaB expression level in the order of HP group < HP + ACA group < ACA group. The expression of TNF-alpha and IL-6 showed the same tendency as seen in the expression of TLR2 and NFkappaB. CONCLUSION: HP induces brain ischemic tolerance via a possible mechanism of activating TLR4 signal pathway and then inhibiting inflammatory response induced by ACA.

Chemisorption of CO2 on nickel surfaces.

CO2 chemisorption on the Ni(111), Ni(100), and Ni(110) surfaces was investigated at the level of density functional theory. It was found that the ability of CO2 chemisorption is in the order of Ni(110) > Ni(100) > Ni(111). CO2 has exothermic chemisorption on Ni(110) and endothermic chemisorption on Ni(111), while it is thermally neutral on Ni(100). It is also found that there is no significant lateral interaction between the adsorbed CO2 at 1/4 monolayer (ML) coverage, while there is stronger repulsive interaction at 1/2 ML. On all surfaces, the chemisorbed CO2 is partially negatively charged, indicating the enhanced electron transfer, and the stronger the electron transfer, the stronger the C=O bond elongation. The bonding nature of the adsorbed CO2 on nickel surfaces has been analyzed. The thermodynamics of CO2 dissociative chemisorption, compared with CO and O adsorption, has been discussed, and the thermodynamic preference is in the sequence Ni(100) > Ni(111) > Ni(110).

[Down-regulation of Toll-like receptor 4 is related to the tolerance to lipopolysaccharide in rat alveolar macrophages].

OBJECTIVE: To explore the change of expression of Toll-like receptor 4 (TLR(4)) related to the tolerance to lipopolysaccharide (LPS) in rat alveolar macrophages. METHODS: Alveolar macrophages obtained from 30 Wistar male rats were randomly divided into a control group, a LPS single-dose stimulation group and a LPS double-dose stimulation group. IL-10 and IL-18 mRNA in alveolar macrophages and the level of TNF-alpha, as indexes of LPS tolerance, were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and enzyme linked immunoads orbeen assay (ELISA), respectively. The expression of TLR(4) was detected by Western Blot. RESULTS: The level of TNF-alpha, and the mRNA for IL-10 and IL-18, and the protein of TLR(4) in the alveolar macrophages stimulated with single-dose LPS (100 ng/ml) were highly increased as compared with the control group [(0.760 +/- 0.030) micro g/L, 2.18 +/- 0.09, 1.83 +/- 0.07, 2.060 +/- 0.060, 148.3 +/- 1.4 vs (0.450 +/- 0.010) micro g/L, 1.16 +/- 0.04, 0.97 +/- 0.03, 1.320 +/- 0.020, 58.1 +/- 0.4 (P < 0.01)], while they were significantly decreased in the alveolar macrophages after re-stimulation with double-dose LPS (100 ng/ml and 500 ng/ml). CONCLUSIONS: (1) The tolerance to LPS in alveolar macrophages can be induced by re-stimulation with LPS. (2) The down-regulated expression of TLR(4) is related to tolerance to LPS.