Direct Visualization of Distorted Twin Boundaries in Ce-Doped GdFeO3.

Utilizing advanced transmission electron microscopy (TEM), the structure at the (110)-type twin boundary (TB) of Ce-doped GdFeO3 (C-GFO) has been investigated with picometer precision. Such a TB is promising to generate local ferroelectricity within a paraelectric system, while precise knowledge about its structure is still largely missing. In this work, a direct measurement of the cation off-centering with respect to the neighboring oxygen is enabled by integrated differential phase contrast (iDPC) imaging, and up to 30 pm Gd off-centering is highly localized at the TB. Further electron energy loss spectroscopy (EELS) analysis demonstrates a slight accumulation of oxygen vacancies at the TB, a self-balanced behavior of Ce at the Gd sites, and a mixed occupation of Fe2+ and Fe3+ at the Fe sites. Our results provide an informative picture with atomic details at the TB of C-GFO, which is indispensable to further push the potential of grain boundary engineering.

Sevoflurane preconditioning alleviates myocardial ischemia reperfusion injury through mitochondrial NAD+-SIRT3 pathway in rats. / 七氟醚预处理通过线粒体NAD+-SIRT3é€šè·¯å‡è½»å¤§é¼ å¿ƒè‚Œç¼ºè¡€å†çŒæ³¨æŸä¼¤.

OBJECTIVES: Myocardial ischemia reperfusion injury (IRI) occurs occasionally in the process of ischemic heart disease. Sevoflurane preconditioning has an effect on attenuating IRI. Preserving the structural and functional integrity of mitochondria is the key to reduce myocardial IRI. Silent information regulator 3 (SIRT3), a class of nicotinamide adenine dinucleotide (NAD+) dependent deacetylases, is an important signal-regulating molecule in mitochondria. This study aims to explore the role of mitochondrial NAD+-SIRT3 pathway in attenuating myocardial IRI in rats by sevoflurane preconditioning. METHODS: A total of 60 male Sprague Dawley (SD) rats were randomly divided into 5 groups (n=12): A sham group (Sham group), an ischemia reperfusion group (IR group), a sevoflurane preconditioning group (Sev group, inhaled 2.5% sevoflurane for 30 min), a sevoflurane preconditioning+SIRT3 inhibitor 3-TYP group (Sev+3-TYP group, inhaled 2.5% sevoflurane for 30 min and received 5 mg/kg 3-TYP), and a 3-TYP group (5 mg/kg 3-TYP). Except for the Sham group, the IR model in the other 4 groups was established by ligating the left anterior descending coronary artery. The size of myocardial infarction was determined by double staining. Serum cardiac troponin I (cTnI) level was measured. The contents of NAD+ and ATP, the activities of mitochondrial complexes I, II, and IV, the content of MDA, the activity of SOD, and the changes of mitochondrial permeability were measured. The protein expression levels of SIRT3, SOD2, catalase (CAT), and voltage dependent anion channel 1 (VDAC1) were detected by Western blotting. The ultrastructure of myocardium was observed under transmission electron microscope. MAP and HR were recorded immediately before ischemia (T0), 30 min after ischemia (T1), 30 min after reperfusion (T2), 60 min after reperfusion (T3), and 120 min after reperfusion (T4). RESULTS: After ischemia reperfusion, the content of NAD+ in cardiac tissues and the expression level of SIRT3 protein were decreased (both P<0.01), and an obvious myocardial injury occurred, including the increase of myocardial infarction size and serum cTnI level (both P<0.01). Correspondingly, the mitochondria also showed obvious damage on energy metabolism, antioxidant function, and structural integrity, which was manifested as: the activities of mitochondrial complexes I, II, and IV, ATP content, protein expression levels of SOD2 and CAT were decreased, while MDA content, VDAC1 protein expression level and mitochondrial permeability were increased (all P<0.01). Compared with the IR group, the content of NAD+ in cardiac tissues and the expression level of SIRT3 protein were increased in the Sev group (both P<0.01); the size of myocardial infarction and the level of serum cTnI were decreased in the Sev group (both P<0.01); the activities of mitochondrial complexes I, II, and IV, ATP content, protein expression levels of SOD2 and CAT were increased, while MDA content, VDAC1 protein expression level, and mitochondrial permeability were decreased in the Sev group (all P<0.01). Compared with the Sev group, the content of NAD+ in cardiac tissues and the expression level of SIRT3 protein were decreased in the Sev+3-TYP group (both P<0.01); the size of myocardial infarction and the level of serum cTnI were increased in the Sev+3-TYP group (both P<0.01); the activities of mitochondrial complexes I, II, and IV, ATP content, protein expression levels of SOD2 and CAT were decreased, while MDA content, VDAC1 protein expression level, and mitochondrial permeability were increased in the Sev+3-TYP group (all P<0.01). CONCLUSIONS: Sevoflurane preconditioning attenuates myocardial IRI through activating the mitochondrial NAD+-SIRT3 pathway to preserve the mitochondrial function.

Switching behaviour of individual Ag-TCNQ nanowires: an in situ transmission electron microscopy study.

The organic semiconductor silver-tetracyanoquinodimethane (Ag-TCNQ) exhibits electrical switching and memory characteristics. Employing a scanning tunnelling microscopy setup inside a transmission electron microscope, the switching behaviour of individual Ag-TCNQ nanowires (NWs) is investigated in detail. For a large number of NWs, the switching between a high (OFF) and a low (ON) resistance state was successfully stimulated by negative bias sweeps. Fitting the experimental I-V curves with a Schottky emission function makes the switching features prominent and thus enables a direct evaluation of the switching process. A memory cycle including writing, reading and erasing features is demonstrated at an individual NW. Moreover, electronic failure mechanisms due to Joule heating are discussed. These findings have a significant impact on our understanding of the switching behaviour of Ag-TCNQ.

A microspectroscopic insight into the resistivity switching of individual Ag-TCNQ nanocrystals.

We investigate the resistivity switching in individual Ag-TCNQ wires with on/off-ratios of up to 10(3). Raman and soft X-ray absorption microspectroscopy studies disclose reverse charge transfer. Quantifying of the fraction of neutral TCNQ within the switched material yields values up to 22.3%. These findings expedite the understanding of the switching process in Ag-TCNQ nanowires.

in situ observation of reversible phase transitions in Gd-doped ceria driven by electron beam irradiation.

Ceria-based oxides are widely utilized in diverse energy-related applications, with attractive functionalities arising from a defective structure due to the formation of mobile oxygen vacancies ( V O ⋅ ⋅ ). Notwithstanding its significance, behaviors of the defective structure and V O ⋅ ⋅ in response to external stimuli remain incompletely explored. Taking the Gd-doped ceria (Ce0.88Gd0.12O2-δ) as a model system and leveraging state-of-the-art transmission electron microscopy techniques, reversible phase transitions associated with massive V O ⋅ ⋅ rearrangement are stimulated and visualized in situ with sub-Šresolution. Electron dose rate is identified as a pivotal factor in modulating the phase transition, and both the V O ⋅ ⋅ concentration and the orientation of the newly formed phase can be altered via electron beam. Our results provide indispensable insights for understanding and refining the microscopic pathways of phase transition as well as defect engineering, and could be applied to other similar functional oxides.

Plasma-induced oxygen defects in titanium dioxide to address the long-term stability of pseudocapacitive MnO2 anode for lithium ion batteries.

In this work, we developed Manganese and Titanium based oxide composites with oxygen defects (MnOx@aTiOy) via plasma processing as anodes of lithium ion batteries. By appropriately adjusting the defect concentration, the ion transport kinetics and electrical conductivity of the electrodes are significantly improved, showing stable capacity retention. Furthermore, the incremental capacity is further activated and long-term stable cycling performance is achieved, with a specific capacity of 829.5 mAh/g at 1 A/g after 2000 cycles. To scrutinize the lithium migration paths and energy barriers in MnO2 and Mn2O3, the density functional theory (DFT) calculations is performed to explore the lithium migration paths and energy barriers. Although the transformation of MnO2 into Mn2O3 through oxygen defects was initially surmised to inhibit Li ions along their standard routes, our results indicate quite the contrary. In fact, the composite's lithium diffusion rate saw a substantial increase. This can be accredited to the pronounced enhancement of conductivity and ion transport efficiency in the amorphous and porous TiOy.

Role of Fe/Co Ratio in Dual Phase Ce0.8Gd0.2O2-δ-Fe3-xCoxO4 Composites for Oxygen Separation.

Dual-phase membranes are increasingly attracting attention as a solution for developing stable oxygen permeation membranes. Ce0.8Gd0.2O2-δ-Fe3-xCoxO4 (CGO-F(3-x)CxO) composites are one group of promising candidates. This study aims to understand the effect of the Fe/Co-ratio, i.e., x = 0, 1, 2, and 3 in Fe3-xCoxO4, on microstructure evolution and performance of the composite. The samples were prepared using the solid-state reactive sintering method (SSRS) to induce phase interactions, which determines the final composite microstructure. The Fe/Co ratio in the spinel structure was found to be a crucial factor in determining phase evolution, microstructure, and permeation of the material. Microstructure analysis showed that all iron-free composites had a dual-phase structure after sintering. In contrast, iron-containing composites formed additional phases with a spinel or garnet structure which likely contributed to electronic conductivity. The presence of both cations resulted in better performance than that of pure iron or cobalt oxides. This demonstrated that both types of cations were necessary to form a composite structure, which then allowed sufficient percolation of robust electronic and ionic conducting pathways. The maximum oxygen flux is jO2 = 0.16 and 0.11 mL/cm2·s at 1000 °C and 850 °C, respectively, of the 85CGO-FC2O composite, which is comparable oxygen permeation flux reported previously.

[Effects of hydrogen sulfide preconditioning on myocardial ischemia reperfusion injury in rats].

OBJECTIVE: To investigate the effects of hydrogen sulfide preconditioning on myocardial ischemia reperfusion injury in rats. METHODS: Sprague-Dawley male rats were divided into 4 groups with 10 in each group: in S group rats received sham operation; in IR group rats were given with NS (1.0 ml/kg iv) 24 h before ischemia; in H group rats were treated with NaHS (0.05 mg/kg iv) 24 h before ischemia; and in D group, NaHS-treated rats received 5-hydroxydecanoate (5-HD) 15 min before ischemia. Rats in IR group,H group and D group were subjected to ischemia by occlusion of coronary artery for 30 min followed by 2 h of reperfusion. At the end of the reperfusion,myocardial infarct size was measured. SAM-s was measured by Western blotting. Plasma SOD activity and MDA were determined at the end of reperfusion. RESULTS: The infarct size was significantly lesser in H group (25.40 % ± 3.54%) than that in IR group (38.27% ±5.64%,P<0.05). The SAM-s protein expression in myocardium was significantly lower in H group than that in IR group. The plasma MDA content was significantly lower and SOD activity was higher in H group than those in IR group,but there was no difference between IR group and D group. CONCLUSION: The hydrogen sulfide preconditioning attenuates myocardial IR injury possibly through down-regulating SAM-s expression,reducing the production of oxygen free radicals and enhancing anti-oxidize effect in rats.

[Proteomics analysis of myocardium after delayed preconditioning with hydrogen sulfide in rat].

OBJECTIVE: To investigate the changes in protein of myocardium after hydrogen sulfide delayed preconditioning by using proteomics technology. METHODS: Sixteen Sprague-Dawley rats were randomly assigned to control (group S) or hydrogen sulfide group (group H), n = 8 for each group. Myocardial ischemia/reperfusion injury model (ischemia 30 minutes followed by reperfusion 120 minutes) was reproduced at 24 hours after preconditioning either with normal saline or hydrogen sulfide for proteomics analysis in group S or group H, and the myocardial tissue was harvested. The total proteins were extracted and separated by two dimensional gel electrophoresis (2-DE), and the differential protein expression spots were analyzed with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). RESULTS: Analysis of 2-DE showed that 929 ± 14 protein spots were found in group S and 906 ± 10 protein spots in group H, and the expression of 15 protein spots was different between two groups. These protein spots were chosen to undergo MALDI-TOF-MS analysis, and 11 proteins were preliminarily identified, including DNA ligase, cystathionine gamma-lyase, transcription initiation factor, NADH dehydrogenase, guanine nucleotide-releasing factor, fructose-bisphosphate aldolase A, glycogen synthase kinase-3, electron transfer flavoprotein subunit beta, glutathione S-transferase, soluble calcium-activated nucleotidase and S-adenosylmethionine synthetase. CONCLUSIONS: Hydrogen sulfide delayed preconditioning of myocardium resulted in the changes in protein expression profiles in the myocardium. The differential proteins might function as anti-oxidants, to improve the energy metabolism of myocardium, confer cytoprotection and protection of respiratory chain, thus conferring cardioprotection.

[Effect of Gingkgo biloba leaf extract induced delayed preconditioning on cytochrome c oxidase expression during myocardial ischemia-reperfusion in rats].

OBJECTIVE: To determine the effect of Gingkgo biloba leaf extract (EGb761) induced delayed preconditioning on cytochrome c oxidase (CcO) expression during myocardial ischemia-reperfusion in rats. METHODS: Four groups (10 in each) of Sprague-Dawley male rats were studied. In the sham group, the rats received no treatment. Rats in the ischemia-reperfusion (IR) group were treated with NS (1.0 mL/kg intravenously) 24 h before ischemia. Rats in the M group were treated with EGb761 (100 mg/kg intravenously) 24 h before the ischemia. In the D group , EGb761-treated rats that received the 5-hydroxydecanoate (5-HD), an inhibitor of mitochondrial KATP channels 15 min before the ischemia. The IR, M, and D groups were subjected to ischemia by 30 min of coronary artery occlusion before 2 h of reperfusion. At the end of the reperfusion, myocardial infarct size was measured. CcO was measured by Western blot. The myocardial ultrastructure was observed under the electron microscope. RESULTS: The infarct size was significantly smaller in the M group [(23.78 ± 4.82)%] than in the I/R group [(37.87 ± 5.92)%] (P<0.05). The CcO protein expression in the myocardium was significantly higher in the M group than in the I/R group(P<0.05). Microscopic examination showed less myocardial damage in the M group than that in the I/R group. The infarct size, CcO protein expression, and myocardial damage had no significant difference between the D group and the I/R group (P>0.05). CONCLUSION: EGb761 induced delayed preconditioning attenuates myocardial ischemia-reperfusion injury possibly through up-regulating CcO expression in rats.

Ultra-thin graphene cube framework@TiO2 heterojunction as high-performance anode materials for lithium ion batteries.

Here, we proposed a new strategy to build the integrated graphene cube (Gr) framework@TiO2 composite to improve the ion transport kinetics and electrical conductivity of TiO2 as a long-life and high-capacity anode for lithium ion batteries. Combined with the salt template method for ultra-thin framework, the distinct structure of Gr@TiO2 shows an excellent electrochemical performance, e.g., initial coulombic efficiency (ICE), rate performance and specific capacity, due to the increased kinetics of lithium ions. Through this method, the integrity is dramatically improved and the pulverization and agglomeration of the anode after long-term cycles are restrained. The optimized Gr@TiO2 displays a high stable reversible capacity of 179.5 mAh g-1 after 4000 cycles at 1 A g-1, excellent rate performance (125.5 mAh g-1 at 5 A g-1). Kinetic studies through Electrochemical Impedance Spectra, Galvanostatic Intermittent Titration Technique and Linear Sweep Voltammetry confirm that the electrical conductivity and ion transport kinetics are dramatically improved through the ultra-thin graphene cube framework as a heterojunction structure of Gr@TiO2.

Ti3C2 MXene Membranes for Gas Separation: Influence of Heat Treatment Conditions on D-Spacing and Surface Functionalization.

Two-dimensional (2D) MXene materials have recently been the focus of membrane research due to their unique properties, such as their single-atomic-layer thickness, flexibility, molecular filtration abilities and microstructural similarities with graphene, which is currently the most efficient precursor material for gas separation applications. In addition, the potential to process nanoscale channels has motivated investigations of parameters which can improve membrane permeability and selectivity. Interlayer spacing and defects, which are still challenging to control, are among the most crucial parameters for membrane performance. Herein, the effect of heat treatment on the d-spacing of MXene nanosheets and the surface functionalization of nanolayers was shown regarding its impact on the gas diffusion mechanism. The distance of the layers was reduced by a factor of over 10 from 0.345 nm to 0.024 nm, the defects were reduced, and the surface functionalization was maintained upon treatment of the Ti3C2 membrane at 500 °C under an Ar/H2 atmosphere as compared to 80 °C under vacuum. This led to a change from Knudsen diffusion to molecular sieving, as demonstrated by single-gas permeation tests at room temperature. Overall, this work shows a simple and promising way to improve H2/CO2 selectivity via temperature treatment under a controlled atmosphere.

Delayed preconditioning by sevoflurane elicits changes in the mitochondrial proteome in ischemia-reperfused rat hearts.

BACKGROUND: Delayed myocardial preconditioning by volatile anesthetics involves changes in DNA transcription and translation. Mitochondria play a central role in myocardial ischemia/reperfusion (I/R) injury and in ischemic or pharmacologic preconditioning. In this study, we investigated whether there are alterations in myocardial mitochondrial protein expression after volatile anesthetic preconditioning (APC) to examine the underlying mechanisms of delayed cardioprotection. METHODS: Thirty-six Sprague-Dawley rats were randomly assigned to 1 of 3 groups (n = 12 for each group). Rats in the delayed APC group were exposed to sevoflurane (2.5% for 60 minutes) 24 hours before myocardial ischemia was induced. Myocardial ischemia in the I/R and APC groups was induced by left coronary artery occlusion for 30 minutes, followed by 120 minutes of reperfusion. The control group received no treatment. The mitochondria fractions were prepared by differential centrifugation with density gradient isolation for proteomic analysis. Two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization with time-of-flight mass spectrometry was used to identify differences in the protein expression from mitochondria of the rat hearts. RESULTS: Fifteen differentially expressed mitochondrial proteins between the APC group and I/R group were identified and the expression patterns of 2 of the proteins were confirmed by Western blot analysis. These proteins were associated with mitochondrial substrate metabolism, respiration, and adenosine triphosphate (ATP)/adenosine diphosphate transport. The modifications of the mitochondrial proteome suggest an enhanced capacity of mitochondria to maintain myocardial ATP levels after I/R injury. CONCLUSION: Delayed sevoflurane myocardial preconditioning induces mitochondrial proteome remodeling, which mainly involves proteins that are related to ATP generation and transport. Therefore, proteomic changes related to bioenergetic balance may be the mechanistic basis of delayed anesthetic myocardial preconditioning.

[Effect of hydrogen sulfide-induced delayed preconditioning on glutathione S-transferase expression during myocardial ischemia-reperfusion in rats].

OBJECTIVE: To investigate the effect of hydrogen sulfide-induced delayed preconditioning on glutathione S-transferase (GST) expression during myocardial ischemia-reperfusion in rats. METHODS: Sprague-Dawley male rats were randomly divided into 4 groups (n= 10 in each): Group S (sham operation group), Group IR (ischemia/reperfusion group), Group H (IR+ NaHS 0.05 mg/kg iv, 24 h before ischemia) and Groups D receiving IR+NaHS 24 h before ischemia and 5-hydroxydecanoate (5-HD)15 min before ischemia. Animals in groups IR, H and D were subjected to ischemia by 30 min of coronary artery occlusion followed by 2 h of reperfusion. At the end of the reperfusion, myocardial infarct size (IS) was examined. Glutathione S-transferase (GST) was measured by Western blotting. The myocardial ultrastructures were observed under the electron microscopy. RESULTS: The IS was significantly smaller in Group H than that in Group IR [(25.40 ± 3.54)% compared with (38.27 ± 5.64)%, P<0.05]. The GST expression in myocardium was significantly higher in Group H than that in Group IR. Microscopic examination showed less myocardial damage in Group H than in Group IR. The protective effects of delayed preconditioning by hydrogen sulfide was prevented by 5-HD pre-treatment. CONCLUSION: The hydrogen sulfide-induced delayed preconditioning attenuates myocardial IR injury possibly through up-regulating glutathione S-transferase expression in rats.

[Proteomics analysis of adenosine A1 receptor agonist-induced delayed myocardial protection in rabbits].

OBJECTIVE: To investigate the changes of myocardial protein expression profiles in 2-chloro-N6-cyclopentyladenosine (CCPA), an adenosine A1 receptor agonist-induced delayed myocardial protection in New Zealand rabbits . METHODS: A total of 8 rabbits were randomly divided into a CCPA group (CCPA group) and a normal saline group (NS group). CCPA and NS were infused into rabbits in the CCPA group and the NS group respectively. Twenty-four hours later, the rabbits were subjected to 30 min left anterior descending coronary artery occlusion and were reperfused for 2 hours, then the ischemic zone tissues of left ventricle were sampled for proteomic analysis.A total of 12 other New Zeland rabbits were divided into a sham group (Sham group), a normal saline group (NS group) and a CCPA group (CCPA group). The expression of αB-crystalline, one of the differential proteins, was confirmed by Western blot. RESULTS: Analysis of two dimensional gel electrophoresis showed that the expression of 55 protein spots were different between the two groups, 17 protein spots were preliminarily identified with the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and Mascot and Expasy bioinformatics software. These proteins included stress proteins, metabolism-associated proteins, signal transduction pathway-related proteins, ionophorous proteins, immunity-associated proteins, and so on. Western blot showed that the expression of αB-crystalline was significantly up-regulated in the CCPA group. CONCLUSION: The myocardial protein expression profiles are changed markedly in the preconditioning late phase of CCPA .The differential proteins might be involved in the delayed cardioprotection induced by CCPA.

Measurement of polarization effects in dual-phase ceria-based oxygen permeation membranes using Kelvin probe force microscopy.

In this study, a dual phase composite (CSO-FC2O) consisting of 60 vol % Ce0.8Sm0.2O1.9 as oxygen-conductive phase and 40 vol % FeCo2O4 as electron-conductive phase was synthesized. TEM measurements showed a relatively pure dual-phase material with only minor amounts of a tertiary (Sm,Ce)(Fe,Co)O3 perovskite phase and isolated residues of a rock salt phase at the grain boundaries. The obtained material was used as a model to demonstrate that a combination of polarization relaxation measurements and Kelvin probe force microscopy (KPFM)-based mapping of the Volta potential before and after the end of polarization can be used to determine the chemical diffusion coefficient of the ceria component of the composite. The KPFM measurements were performed at room temperature and show diffusion coefficients in the range of 3 × 10-13 cm2·s-1, which is comparable to values measured for single-phase Gd-doped ceria thin films using the same method.

DNA introduces an independent temperature responsiveness to thermosensitive microgels and enables switchable plasmon coupling as well as controlled uptake and release.

A novel DNA-microgel hybrid system with dual thermal responsiveness is introduced uitilizing covalent coupling of single stranded DNA (ssDNA) to thermoresponsive microgels (µGs). The spatial distribution of the coupling sites for the ssDNA was characterized with 3D superresolution fluorescence microscopy. The DNA-functionalized µGs remain thermoresponsive and can take up dye-labeled complementary ssDNA, which can be released again by overcoming the dehybridization temperature of the DNA independently of the volume phase transition (VPT) of the µGs. The same holds for nano-objects represented by plasmonic gold nanoparticles (AuNPs), the penetration depth of which was visualized via TEM tomography and 3D reconstruction and which show enhanced plasmonic coupling in the collapsed state of the µG and thus gets switchable. In contrast, if ssDNA was taken up just by non-specific interactions, i.e. into non-functionalized µGs, its release is temperature-independent and can only be induced by increasing the salt concentration. Thus, the incorporated ssDNA represents highly selectice binding sites determined by their base number and sequence, which makes the VPT, beeing determined by the µG composition, and the reversible uptake and release enabled through programmable DNA hybridization are independent features. The combination with the typically high biocompatibility and the retained swellability and permeability hold promise for new fundamental insights as well as for potential applications in biological environments.

The formation and utility of sub-angstrom to nanometer-sized electron probes in the aberration-corrected transmission electron microscope at the University of Illinois.

We evaluate the probe forming capability of a JEOL 2200FS transmission electron microscope equipped with a spherical aberration (Cs) probe corrector. The achievement of a real space sub-Angstrom (0.1 nm) probe for scanning transmission electron microscopy (STEM) imaging is demonstrated by acquisition and modeling of high-angle annular dark-field STEM images. We show that by optimizing the illumination system, large probe currents and large collection angles for electron energy loss spectroscopy (EELS) can be combined to yield EELS fine structure data spatially resolved to the atomic scale. We demonstrate the probe forming flexibility provided by the additional lenses in the probe corrector in several ways, including the formation of nanometer-sized parallel beams for nanoarea electron diffraction, and the formation of focused probes for convergent beam electron diffraction with a range of convergence angles. The different probes that can be formed using the probe corrected STEM opens up new applications for electron microscopy and diffraction.

[Effect of isoflurane delayed preconditioning on the expression of Bcl-2 and caspase-3 in myocardium during ischemia reperfusion in rabbits].

OBJECTIVE: To investigate the effect of isoflurane delayed preconditioning on the activation of caspase-3 and the expression of Bcl-2 in rabbit myocardium during ischemia reperfusion and the possible mechanism. METHODS: Forty New Zealand male white rabbits were randomly divided into 4 groups: a sham group (Group C), an I/R group, an isoflurane group (Group S), and an isoflurane + opioid recepters inhibitor group (Group N). Group S was exposed to 2.0% isoflurane for 2 h. Group N was given naloxone (6.0 mg/kg) before exposing to 2.0% isoflurane. Group C and Group I/R were exposed for 2 h to 100% oxygen, serving as untreated controls. Twenty-four hours later, Group S and Group N underwent 40 min of coronary occlusion followed by 2 h of reperfusion. At the end of the reperfusion, infarct size(IS) and area at risk(AAR) were defined by Evans and TTC staining. The myocardial ultrastructure was observed by electron microscopy. The levels of the myocardial Bcl-2 and caspase-3 expression were determined by Western blot. RESULTS: The caspase-3 activity of Group S was significantly lower than that of Group I/R(P<0.05). The IS was significantly reduced in Group S(19.7%+/-2.8%) as compared with Group I/R(37.8%+/-1.7%) (P<0.05). Microscopic examination showed less myocardial damage in Group S than in Group I/R. CONCLUSION: Isoflurane delayed preconditioning can inhibit the apoptosis of myocardium by up-regulating the expression of Bcl-2 and down-regulating the activation of caspase-3, which may be part of the molecular mechanism of isoflurane delayed preconditioning on myocardial preservation.

Effect of obesity on the prognosis and recurrence of prostate cancer after radical prostatectomy: a meta-analysis.

BACKGROUND: Obesity has been found to be closely related to the increased risk of fatal prostate cancer (PCa), however there remains no evidence that further clarifies the relationship between obesity and the postoperative recurrence and poor prognosis of PCa. In this study, a systematic review and meta-analysis were performed to systematically evaluate the effect of obesity on the prognosis and recurrence of PCa after radical prostatectomy (RP). METHODS: A literature search of the PubMed, Web of Science, and Embase databases was performed covering articles published between January 2013 and January 2020. Articles regarding the correlation between body mass index (BMI) and the prognosis and recurrence of PCa following RP were included in the meta-analysis. Two investigators independently screened the literature and extracted relevant data including publication information, key results, number of cancer cases, and multivariable-adjusted odds ratios (ORs) with 95% confidence intervals (CIs). Meta-analysis was performed using RevMan 5.3 and Stata 16.0 software, and forest plots, funnel plots, and sensitivity analysis were also conducted. RESULTS: A total of 14 articles were included, all of which were analyzed for clinicopathological characteristics. Eight articles reported the biochemical recurrence (BCR) with prostate-specific antigen (PSA) as the predictor, and six articles reported the positive surgical margins (PSM). The meta-analysis showed that obese PCa patients had more postoperative recurrence and poor prognosis compared with the normal weight PCa patients, and the difference was statistically significant (OR =1.25, 95% CI: 1.10, 1.43). BCR exhibited no significant difference between obese and non-obese PCa patients after surgery (OR =1.2, 95% CI: 0.96, 1.46), and there were also no notable differences in PSM between the groups (OR =1.16, 95% CI: 0.99, 1.36). Subgroup analysis showed that obese PCa patients in the Americas (95% CI: 1.11, 1.37) and Europe (95% CI: 1.11, 1.78) were more likely to have surgical recurrence and poor prognosis (OR =1.40). Obese patients in the Americas were also more likely to have BCR after surgery (95% CI: 1.07, 1.36). CONCLUSIONS: Obesity easily leads to poor prognosis and recurrence of PCa after RP.