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1.
Nat Commun ; 15(1): 4318, 2024 May 21.
Article in English | MEDLINE | ID: mdl-38773067

ABSTRACT

Neural circuits with specific structures and diverse neuronal firing features are the foundation for supporting intelligent tasks in biology and are regarded as the driver for catalyzing next-generation artificial intelligence. Emulating neural circuits in hardware underpins engineering highly efficient neuromorphic chips, however, implementing a firing features-driven functional neural circuit is still an open question. In this work, inspired by avoidance neural circuits of crickets, we construct a spiking feature-driven sensorimotor control neural circuit consisting of three memristive Hodgkin-Huxley neurons. The ascending neurons exhibit mixed tonic spiking and bursting features, which are used for encoding sensing input. Additionally, we innovatively introduce a selective communication scheme in biology to decode mixed firing features using two descending neurons. We proceed to integrate such a neural circuit with a robot for avoidance control and achieve lower latency than conventional platforms. These results provide a foundation for implementing real brain-like systems driven by firing features with memristive neurons and put constructing high-order intelligent machines on the agenda.


Subject(s)
Action Potentials , Models, Neurological , Neural Networks, Computer , Neurons , Robotics , Robotics/instrumentation , Robotics/methods , Neurons/physiology , Animals , Action Potentials/physiology , Gryllidae/physiology , Nerve Net/physiology , Artificial Intelligence , Avoidance Learning/physiology
2.
J Colloid Interface Sci ; 664: 349-359, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38479271

ABSTRACT

Surface reconstruction of electrocatalysts is an effective strategy to modulate the space charge distribution to enhance the electrocatalytic activity. The p-n heterostructured FeP/CoP-2D octagonal nanoplates were successfully constructed by cation-exchange method. The space charge effect caused by the p-n heterojunction accelerated the electron transfer, optimized the electronic structure, and improved the activity of the active sites during the oxygen evolution reaction process. As a result, FeP/CoP-2D required only 247 mV overpotential to achieve a current density of 10 mA cm-2 with a Tafel slope as low as 68 mV dec-1. Density-functional theory calculations confirmed that the construction of p-n heterojunctions can enhance the adsorption of *OH in the active centers and optimize the Gibbs free energy of the OER reaction. This study provides an effective and feasible strategy for constructing p-n heterojunctions to modulate the space charge state for optimizing the OER performance of electrocatalysts.

3.
BMC Geriatr ; 24(1): 61, 2024 Jan 15.
Article in English | MEDLINE | ID: mdl-38225566

ABSTRACT

BACKGROUND: Metabolic syndrome (MetS) is a pathological condition characterized by the abnormal clustering of several metabolic components and has become a major public health concern. We aim to investigate the potential link of Systemic immunity-inflammation index (SII) on MetS and its components. METHODS AND RESULT: Weighted multivariable logistic regression was conducted to assess the relationship between SII and MetS and its components. Restricted cubic spline (RCS) model and threshold effect analysis were also performed. A total of 6,999 U.S. adults were enrolled. Multivariate model found that SII were positively associated with MetS (OR = 1.18;95CI%:1.07-1.30) and hypertension (OR = 1.22; 95CI%:1.12-1.34) in a dose-dependent manner. When SII was converted into a categorical variable, the risk of MetS increased by 36% and the risk of hypertension increased by 53% in the highest quantile of SIIs. The RCS model confirmed linear associations between SII and MetS, as well as a non-linear association between SII and certain components of MetS, including hypertension, hyperglycemia, low HDL, and hyperlipidemia. Meanwhile, the relationship between SII and hypertension presents a J-shaped curve with a threshold of 8.27, above which the risk of hypertension increases. Furthermore, in MetS and hypertension, age, sex, body mass index (BMI), and race were not significantly associated with this positive association based on subgroup analyses and interaction tests(p for interaction > 0.05). CONCLUSIONS: The present study indicated that there was a higher SII association with an increased risk of MetS and hypertension in adults. However, further prospective cohort studies are required to establish a causal relationship between SII and MetS, as well as its components.


Subject(s)
Hypertension , Metabolic Syndrome , Humans , Metabolic Syndrome/diagnosis , Metabolic Syndrome/epidemiology , Cross-Sectional Studies , Hypertension/diagnosis , Hypertension/epidemiology , Hypertension/complications , Body Mass Index , Inflammation/diagnosis , Inflammation/epidemiology , Nutrition Surveys
4.
Small ; 20(15): e2307095, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38009720

ABSTRACT

Transition metal selenides are considered as promising anode materials for potassium-ion batteries (PIBs) due to their high theoretical capacities. However, their applications are limited by low conductivity and large volume expansion. Herein, sugar-gourd-shaped carbon nanofibers embedded with heterostructured ZnCo-Se nanocages are prepared via a facile template-engaged method combined with electrospinning and selenization process. In this hierarchical ZnCo-Se@NC/CNF, abundant phase boundaries of CoSe2/ZnSe heterostructure can promote interfacial electron transfer and chemical reactivity. The interior porous ZnCo-Se@NC nanocage structure relieves volume expansion and maintains structural integrity during K+ intercalation and deintercalation. The exterior spinning carbon nanofibers connect the granular nanocages in series, which prevents the agglomeration, shortens the electron transport distance and enhances the reaction kinetics. As a self-supporting anode material, ZnCo-Se@NC/CNF delivers a high capacity (362 mA h g-1 at 0.1 A g-1 after 100 cycles) with long-term stability (95.9% capacity retention after 1000 cycles) and shows superior reaction kinetics with high-rate K-storage. Energy level analysis and DFT calculations illustrate heterostructure facilitates the adsorption of K+ and interfacial electron transfer. The K+ storage mechanism is revealed by ex situ XRD and EIS analyses. This work opens a novel avenue in designing high-performance heterostructured anode materials with ingenious structure for PIBs.

5.
Small ; 19(52): e2305241, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37635103

ABSTRACT

Space charge transfer is an effective strategy to regulate the electron density of narrow bandgap semiconductors for enhancing electrocatalytic activity. Herein, the CoNiLDH/FeOOH n-n heterojunction hollow nanocages structure is constructed. The hollow structure provides abundant catalytic active sites and enhances mass transfer. The space charge region in the n-n heterojunction significantly promotes the adsorption of OH- and electron transfer; and the built-in electric field accelerates the electron transport, optimizes the electronic structure during the catalytic reaction process, and ensures the stability of surface charged active center sites in the heterojunction. Thus, CoNiLDH/FeOOH delivers an excellent oxygen evolution reaction (OER) overpotential of 250 mV to achieve a current density of 10 mA cm-2 with a small Tafel slope of 60 mV dec-1 , and superior electrocatalytic durability for 210 h at a high current density. Density functional theory calculations further verify that the space charge effect and built-in electric field in the n-n heterojunction of CoNiLDH/FeOOH can improve the electron transfer and lower the adsorption energy of OH- and the reaction energy barrier of the rate-determining step. This work provides a new fundamental understanding of the space charge effect of semiconductor heterojunction during the electrocatalytic process for developing more efficient OER electrocatalysts.

6.
Cell Prolif ; 56(2): e13362, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36433732

ABSTRACT

Acute kidney injury (AKI) is often secondary to sepsis. Increasing evidence suggests that mitochondrial dysfunction contributes to the pathological process of AKI. In this study, we aimed to examine the regulatory roles of Sirt3 in Lipopolysaccharide (LPS)-induced mitochondrial damage in renal tubular epithelial cells (TECs). Sirt3 knockout mice were intraperitoneally injected with LPS, and cultured TECs were stimulated with LPS to evaluate the effects of Sirt3 on mitochondrial structure and function in TECs. Electron microscopy was used to assess mitochondrial morphology. Immunofluorescence staining was performed to detect protein expression and examine mitochondrial morphology. Western blotting was used to quantify protein expression. We observed that LPS increased apoptosis, induced disturbances in mitochondrial function and dynamics, and downregulated Sirt3 expression in a sepsis-induced AKI mouse model and human proximal tubular (HK-2) cells in vitro. Sirt3 deficiency further exacerbated LPS-induced renal pathological damage, apoptosis and disturbances in mitochondrial function and dynamics. On the contrary, Sirt3 overexpression in HK-2 cells alleviated these lesions. Functional studies revealed that Sirt3 overexpression alleviated LPS-induced mitochondrial damage and apoptosis in TECs by promoting OPA1-mediated mitochondrial fusion through the deacetylation of i-AAA protease (YME1L1), an upstream regulatory molecule of OPA1. Our study has identified Sirt3 as a vital factor that protects against LPS-induced mitochondrial damage and apoptosis in TECs via the YME1L1-OPA1 signaling pathway.


Subject(s)
Acute Kidney Injury , Sepsis , Sirtuin 3 , Mice , Animals , Humans , Sirtuin 3/metabolism , Lipopolysaccharides/pharmacology , Acute Kidney Injury/metabolism , Epithelial Cells/metabolism , Mice, Knockout , Apoptosis , ATPases Associated with Diverse Cellular Activities/metabolism , Metalloendopeptidases/adverse effects , Metalloendopeptidases/metabolism , Mitochondrial Proteins/metabolism
7.
Front Neurosci ; 16: 982850, 2022.
Article in English | MEDLINE | ID: mdl-36263363

ABSTRACT

Cochleas are the basis for biology to process and recognize speech information, emulating which with electronic devices helps us construct high-efficient intelligent voice systems. Memristor provides novel physics for performing neuromorphic engineering beyond complementary metal-oxide-semiconductor technology. This work presents an artificial cochlea based on the shallen-key filter model configured with memristors, in which one filter emulates one channel. We first fabricate a memristor with the TiN/HfOx/TaOx/TiN structure to implement such a cochlea and demonstrate the non-volatile multilevel states through electrical operations. Then, we build the shallen-key filter circuit and experimentally demonstrate the frequency-selection function of cochlea's five channels, whose central frequency is determined by the memristor's resistance. To further demonstrate the feasibility of the cochlea for system applications, we use it to extract the speech signal features and then combine it with a convolutional neural network to recognize the Free Spoken Digit Dataset. The recognition accuracy reaches 92% with 64 channels, compatible with the traditional 64 Fourier transform transformation points of mel-frequency cepstral coefficients method with 95% recognition accuracy. This work provides a novel strategy for building cochleas, which has a great potential to conduct configurable, high-parallel, and high-efficient auditory systems for neuromorphic robots.

8.
Gels ; 8(8)2022 Jul 22.
Article in English | MEDLINE | ID: mdl-35892718

ABSTRACT

Both sodium alginate and polyethyleneimine (PEI) have a good ability to adsorb heavy metal ions. PEI and sodium alginate were used as important precursors to synthesize positively charged carbon nanoparticles (p-CNDs) with hydroxyl and carboxyl, and negatively charged carbon nanoparticles (n-CNDs) with amino, respectively. The carbon nanoparticles (CNDs) aerogel with a large specific surface area and rich functional groups were constructed by self-assembled p-CNDs and n-CNDs via electrostatic attraction for adsorption of heavy metal ions in water. The results show that CNDs aerogel has good adsorption properties for Pb2+ (96%), Cu2+ (91%), Co2+ (86%), Ni2+ (82%), and Cd2+ (78%). Furthermore, the fluorescence emission intensity of CNDs aerogel will gradually decrease with the increase in the adsorption rate, indicating that it can detect the adsorption process synchronously. In addition, the cytotoxicity test reveals that CNDs have good biocompatibility and will not cause secondary damage to biological cells.

9.
J Colloid Interface Sci ; 624: 251-260, 2022 Oct 15.
Article in English | MEDLINE | ID: mdl-35660894

ABSTRACT

Complex hollow structure nanostructure is regarded as the desired approach to alleviating the volume change of lithium-ion batteries (LIBs). In this work, ZnS/NiS/NiS2 composite with a distinctive hierarchical hollow porous urchin-like structure was prepared through pyrolysis of bimetal-organic frameworks obtained by one-step solvothermal and firstly used as anodes for LIBs. Varying the metal molar ratios allows the control of the surface area and pore size distribution of ZnS/NiS/NiS2. The obtained composite with a hollow porous urchin-like structure exhibits high porosity, large specific surface area, and strong synergetic interaction between ZnS and NiS/NiS2 can greatly buffer the volume expansion to keep the mechanical stability, ensure sufficient contact region between electrolyte and electrodes and shorten the Li+ transfer distance, meanwhile, the carbon derived from organic ligand of bimetal-organic frameworks also constructs the conductive matrix to accelerate electrons transfer. Based on the above outstanding properties, the obtained material delivers excellent rate capacity, superior reversible capacity, and long-cycle stability, especially disclosing a capacity of 615 mAh·g-1 after 300 cycles at 2 A·g-1. This work proposes a feasible strategy to obtain a unique hollow porous urchin-like structure through pyrolysis of bimetal organic frameworks, it can be extended to fabricate other mixed metal sulfides nanostructures with excellent electrochemical performances.

10.
Adv Mater ; 34(24): e2200481, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35429020

ABSTRACT

Multimode-fused sensing in the somatosensory system helps people obtain comprehensive object properties and make accurate judgments. However, building such multisensory systems with conventional metal-oxide-semiconductor technology presents serious device integration and circuit complexity challenges. Here, a multimode-fused spiking neuron (MFSN) with a compact structure to achieve human-like multisensory perception is reported. The MFSN heterogeneously integrates a pressure sensor to process pressure and a NbOx -based memristor to sense temperature. Using this MFSN, multisensory analog information can be fused into one spike train, showing excellent data compression and conversion capabilities. Moreover, both pressure and temperature information are distinguished from fused spikes by decoupling the output frequencies and amplitudes, supporting multimodal tactile perception. Then, a 3 × 3 MFSN array is fabricated, and the fused frequency patterns are fed into a spiking neural network for enhanced tactile pattern recognition. Finally, a larger MFSN array is simulated for classifying objects with different shapes, temperatures, and weights, validating the feasibility of the MFSNs for practical applications. The proof-of-concept MFSNs enable the building of multimodal sensory systems and contribute to the development of highly intelligent robotics.


Subject(s)
Robotics , Touch Perception , Humans , Neural Networks, Computer , Neurons/physiology , Semiconductors
11.
Cell Signal ; 93: 110284, 2022 05.
Article in English | MEDLINE | ID: mdl-35182747

ABSTRACT

BACKGROUND: Sirtuin 3 (SIRT3) is a crucial regulator of mitochondrial function and is associated with injury and repair in acute kidney injury (AKI). To investigate whether mitochondrial damage and early renal fibrosis are associated with decreased renal SIRT3 levels, we established an in vivo model. METHODS: In vivo, we established ischaemia-reperfusion-induced AKI (IR-AKI) models in wild-type (WT) and SIRT3-knockout (SIRT3-KO) mice. Serum creatinine (Scr) and blood urea nitrogen (BUN) were measured by an automatic biochemical analyser, and renal pathological changes were examined by haematoxylin and eosin (HE) staining. Renal fibrosis in mice was assessed by Masson's trichrome staining. The expression of SIRT3, renal fibrosis-related markers (FN and α-SMA), and mitochondrial markers (DRP1, FIS1, OPA1, and MFN1) was measured by Western blotting. Morphological changes in mitochondria in renal tubular epithelial cells were analysed by transmission electron microscopy (TEM). RESULTS: The levels of Scr and BUN were elevated with severe renal pathological damage in the IR-AKI model, especially in SIRT3-KO mice. In the IR-AKI model, the obvious increases in FN and α-SMA protein levels suggested that there was severe fibrosis in the kidney tissue, OPA1 and MFN1 protein levels were reduced while DRP1 and FIS1 protein levels were greatly increased. TEM photomicrographs showed that mitochondrial fragmentation was increased in the renal tubular epithelial cells of mice with IR injury. SIRT3-KO mice exhibited exacerbated changes. CONCLUSION: Our findings indicate that SIRT3 plays a significant role in early-stage fibrosis after IR-AKI by regulating mitochondrial dynamics and that SIRT3 deficiency exacerbates renal dysfunction and renal fibrosis.


Subject(s)
Acute Kidney Injury , Reperfusion Injury , Sirtuin 3 , Acute Kidney Injury/chemically induced , Animals , Female , Fibrosis , Humans , Ischemia/metabolism , Kidney/pathology , Male , Mice , Mice, Knockout , Reperfusion , Reperfusion Injury/metabolism , Sirtuin 3/metabolism
12.
Front Neurosci ; 15: 786694, 2021.
Article in English | MEDLINE | ID: mdl-35069102

ABSTRACT

Inspired by the human brain, the spike-based neuromorphic system has attracted strong research enthusiasm because of the high energy efficiency and powerful computational capability, in which the spiking neurons and plastic synapses are two fundamental building blocks. Recently, two-terminal threshold switching (TS) devices have been regarded as promising candidates for building spiking neurons in hardware. However, how circuit parameters affect the spiking behavior of TS-based neurons is still an open question. Here, based on a leaky integrate-and-fire (LIF) neuron circuit, we systematically study the effect of both the extrinsic and intrinsic factors of NbO x -based TS neurons on their spiking behaviors. The extrinsic influence factors contain input intensities, connected synaptic weights, and parallel capacitances. To illustrate the effect of intrinsic factors, including the threshold voltage, holding voltage, and high/low resistance states of NbO x devices, we propose an empirical model of the fabricated NbO x devices, fitting well with the experimental results. The results indicate that with enhancing the input intensity, the spiking frequency increases first then decreases after reaching a peak value. Except for the connected synaptic weights, all other parameters can modulate the spiking peak frequency under high enough input intensity. Also, the relationship between energy consumption per spike and frequency of the neuron cell is further studied, leading guidance to design neuron circuits in a system to obtain the lowest energy consumption. At last, to demonstrate the practical applications of TS-based neurons, we construct a spiking neural network (SNN) to control the cart-pole using reinforcement learning, obtaining a reward score up to 450. This work provides valuable guidance on building compact LIF neurons based on TS devices and further bolsters the construction of high-efficiency neuromorphic systems.

13.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 27(6): 1933-1937, 2019 Dec.
Article in Chinese | MEDLINE | ID: mdl-31839062

ABSTRACT

OBJECTIVE: To investigate the level of serum microRNA-609 and its clinical prognostic value in patients with thalassemia. METHODS: One hundred and twenty-seven patients with thalassemia treated in our hospital from April 2017 to April 2018 were selected, 100 healthy persons were selected as control group. The changes of miR-609 were analyzed by RT-PCR, the relationship between miR-609 and clinical indicators of thalassemia was analyzed, and the prognostic risk factors of thalassemia were evaluated by multivariate logistic regression analysis. RESULTS: The relative expression level of miR-609 in thalassemia patients was 3.17±0.24, which was significantly higher than that in control group (P<0.05). The levels of ALT, Plt and MCH in patients with high expression of miR-609 were significantly higher than those in patients with low expression of miR-609 (P<0.05). The levels of Hb and sICAM-1 in patients with high expression of miR-609 were significantly lower than those in patients with low expression of miR-609 (P<0.05). There was no correlation between the level of miR-609 and the patient's sex, age and AST (P>0.05). The incidence rate of mild anemia in high expression group was significantly lower than that in low expression group (P<0.05). There was no correlation between the level of miR-609 and the incidence rate of moderate anemia (P>0.05). The number of patients with severe anemia in the miR-609 high expression group was higher than that in miR-609 low expression group (P<0.05). The incidence rate of dizziness, fatigue and fever in patients with miR-609 high expression group was significantly higher than those in patients with miR-609 low expression (P<0.05). There was no correlation between the level of miR-609 and the incidence rate of nausea in patients with thalassemia. ROC curve showed that the AUC value of microRNA-609 was 0.862, the sensitivity was 83.6%, and the specificity was 84.1%, which suggested that miR-609 had a high diagnostic value for thalassemia. Multivariate logistic regression analysis showed that MCH and mir-609 were risk factors for poor prognosis of thalassemia patients. CONCLUSION: The increased level of serum miR-609 in patients with thalassemia is a risk factor for poor prognosis and can be used as a reference index for evaluating the efficacy for patients.


Subject(s)
Thalassemia , Biomarkers, Tumor , Humans , MicroRNAs , Prognosis , ROC Curve , Thalassemia/genetics
14.
ISA Trans ; 84: 111-117, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30316571

ABSTRACT

The optimal modified performance of the multi-input multi-output (MIMO) networked control systems (NCSs) with encoding-decoding, channel noise in the forward channel and packet dropouts, quantization in the feedback channel is investigated in this paper. A new and efficient tracking performance index for the NCSs is presented which prevents variations in the tracking error where there is no integrator in the plant. The optimal modified performance is obtained by the method of coprime factorization and partial fraction. The results demonstrate that the optimal modified performance is related to the locations of the non-minimum phase (NMP) zeros, unstable poles of the given plant as well as their directions. In addition, the modified factor, packet dropouts probability, channel noise and encoding-decoding are also closely related to optimal modified performance of the NCSs. Finally, we present some particular examples to illustrate the theoretical results.

15.
ACS Appl Mater Interfaces ; 9(2): 1407-1415, 2017 Jan 18.
Article in English | MEDLINE | ID: mdl-28045243

ABSTRACT

Three-dimensional (3D) interconnected spherical graphene framework-decorated SnS nanoparticles (3D SnS@SG) is synthesized by self-assembly of graphene oxide nanosheets and positively charged polystyrene/SnO2 nanospheres, followed by a controllable in situ sulfidation reaction during calcination. The SnS nanoparticles with diameters of ∼10-30 nm are anchored to the surface of the spherical graphene wall tightly and uniformly. Benefiting from the 3D interconnected spherical graphene framework and subtle SnS nanoparticles, the generated Li2S could keep in close contact with Sn to make possible the in situ conversion reaction SnS + 2Li+ + 2e- ↔ Sn + Li2S. As a result, the 3D SnS@SG as the anode material for lithium ion batteries shows a high initial Coulombic efficiency of 75.3%. Apart from the irreversible capacity loss of 3D spherical graphene, the initial Coulombic efficiency of SnS in the 3D SnS@SG composite is as high as 99.7%, demonstrating the almost complete reversibility of Li2S in this system. Furthermore, it also exhibits an excellent reversible capacity (800 mAh g-1 after 100 cycles at 0.1 C and 527.1 mAh g-1 after 300 cycles at 1 °C) and outstanding rate capability (380 mAh g-1 at 5 °C).

16.
Article in English | MEDLINE | ID: mdl-24582336

ABSTRACT

In this paper, the photochemical and photobiological characters of the active radicals of berberine (BBR) was investigated for finding an efficient and safe photosensitizer with highly active transient products using in Photodynamic therapy (PDT) study. The active species of BBR was generated and identified by using pulse radiolysis method. In neutral aqueous solution, BBR react with hydrated electron and hydroxyl radical, forming the radical anion and neutral radical of BBR, and the related reaction rates were determined as 3.5×10(10) and 6.7×10(9) M(-1) s(-1), respectively. Further, the capability of BBR to photosensitize DNA cleavage was testified by laser flash photolysis (LFP) method, the results demonstrated that BBR neutral radical could react with guanine mononucleotide (K=1.9×10(9) M(-1) s(-1)) via electron transfer to give the guanine neutral radical. Additionally BBR selective cleavage single and double strand DNA at guanine moiety was observed. Finally, combining with the thermodynamic calculation, the possible photodamage mechanism of dGMP and DNA induced by BBR was clarified.


Subject(s)
Berberine/chemistry , Photolysis , Pulse Radiolysis , Absorption, Physicochemical , Animals , Anions , Cattle , DNA/chemistry , Deoxyguanine Nucleotides/chemistry , Photosensitizing Agents/chemistry , Solutions
17.
Can J Physiol Pharmacol ; 90(10): 1394-402, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23067403

ABSTRACT

Myocardial ischemia and reperfusion (MI/R) injury is associated with activation of the complement system. Complement activation generates a series of bioactive substances, including early (C3a, C3b) and terminal (C5a, C5b-9) components. The terminal complement components are key mediators of MI/R injury. This study investigated whether C5 shRNA preconditioning has protective effects following MI/R injury and its potential mechanism. Rats were injected with C5 shRNA 2 days before induction of ischemia. The effects of C5 shRNA were evaluated by the assessment of heart function, infarct size, histopathology, inflammatory cytokine levels, and the plasma level of troponin T. Akt phosphorylation was assessed by immunoblotting. C5 shRNA efficiently inhibited C5 expression both in vitro and in vivo, and attenuated MI/R injury. C5 shRNA preconditioning significantly decreased the level of troponin T and the production of pro-inflammatory cytokine. The infarct size was decreased by 40% in C5 shRNA treated rats. Akt phosphorylation increased after C5 shRNA preconditioning. These results suggest that C5 shRNA preconditioning in rats has protective effects following MI/R injury; this may be partly effected by mediating the activation of the PI3K pathway and by phosphorylation of Akt.


Subject(s)
Complement C5/antagonists & inhibitors , Gene Silencing , Myocardial Reperfusion Injury/prevention & control , RNA, Small Interfering/therapeutic use , Animals , Complement C5/genetics , Complement C5/metabolism , HEK293 Cells , Humans , Male , Myocardial Infarction/genetics , Myocardial Infarction/prevention & control , Myocardial Ischemia/physiopathology , Myocardial Reperfusion Injury/genetics , Myocardial Reperfusion Injury/pathology , Myocardial Reperfusion Injury/physiopathology , Phosphatidylinositol 3-Kinase/chemistry , Phosphatidylinositol 3-Kinase/metabolism , Phosphorylation , Protein Processing, Post-Translational , Proto-Oncogene Proteins c-akt/metabolism , Random Allocation , Rats , Rats, Sprague-Dawley , Signal Transduction , Up-Regulation , Ventricular Dysfunction, Left/genetics , Ventricular Dysfunction, Left/prevention & control
18.
Article in English | MEDLINE | ID: mdl-22765939

ABSTRACT

In the present paper, the interaction between model protein lysozyme (Lys) and antitumorigenic berberine (BBR) was investigated by spectroscopic methods, for finding an efficient and safe photosensitizer with highly active transient products using in photodynamic therapy study. The fluorescence data shows that the binding of BBR could change the environment of the tryptophan (Trp) residues of Lys, and form a new complex. Static quenching is the main fluorescence quenching mechanism between Lys and BBR, and there is one binding site in Lys for BBR and the type of binding force between them was determined to be hydrophobic interaction. Furthermore, the possible interaction mechanism between BBR and Lys under the photoexcitation was studied by laser flash photolysis method, the results demonstrated that BBR neutral radicals (BBR(-H)) react with Trp (K=3.4×10(9)M(-1)s(-1)) via electron transfer to give the radical cation (Trp/NH(+)) and neutral radical of Trp (TrpN). Additionally BBR selectively oxidize the Trp residues of Lys was also observed by comparing the transient absorption spectra of their reaction products. Through thermodynamic calculation, the reaction mechanisms between (3)BBR and Trp or Lys were determined to be electron transfer process.


Subject(s)
Berberine/metabolism , Muramidase/metabolism , Absorption , Berberine/chemistry , Binding Sites , Fluorescence , Kinetics , Muramidase/chemistry , Protein Binding , Spectrometry, Fluorescence , Tryptophan/metabolism
19.
J Photochem Photobiol B ; 103(2): 186-91, 2011 May 03.
Article in English | MEDLINE | ID: mdl-21458292

ABSTRACT

Hydrogen sulfide is the third endogenous signaling gasotransmitter, following nitric oxide and carbon monoxide. Recent studies showed that hydrogen sulfide could alleviate many diseases which were related to the oxidative damage of tissues. It reminded us that hydrogen sulfide might serve as an antioxidant to reduce oxidative pressure. This study showed that hydrogen sulfide protected lysozyme from photo-oxidation induced by riboflavin (RF). Laser flash photolysis was used to explore the mechanisms of antioxidant activity of hydrogen sulfide. The scavenging effects of hydrogen sulfide on the triplet state of riboflavin (³RF(*)) and radicals of tryptophan and tyrosine (TyrO· and TrpN·) were attributed to the protection of lysozyme from photo-oxidation. The results suggested that hydrogen sulfide could serve as an antioxidant in alleviation of oxidative pressure.


Subject(s)
Antioxidants/pharmacology , Hydrogen Sulfide/pharmacology , Muramidase/metabolism , Riboflavin/pharmacology , Oxidation-Reduction , Photochemistry , Photolysis , Riboflavin/antagonists & inhibitors , Tryptophan/chemistry , Tyrosine/chemistry
20.
Article in English | MEDLINE | ID: mdl-21419692

ABSTRACT

As a metabolite of aspirin in vivo, salicylic acid was proved to protect lysozyme from riboflavin-mediated photooxidation in this study. The antioxidative properties of salicylic acid were further studied by using time-resolved laser flash photolysis of 355 nm. It can quench the triplet state of riboflavin via electron transfer from salicylic acid to the triplet state of riboflavin with a reaction constant of 2.25×10(9) M(-1) s(-1). Mechanism of antioxidant activities of salicylic acid on lysozyme oxidation was discussed. Salicylic acid can serve as a potential antioxidant to quench the triplet state of riboflavin and reduce oxidative pressure.


Subject(s)
Light , Muramidase/drug effects , Muramidase/radiation effects , Protective Agents/pharmacology , Riboflavin/pharmacology , Salicylic Acid/pharmacology , Absorption/drug effects , Absorption/radiation effects , Antioxidants/pharmacology , Electrophoresis, Polyacrylamide Gel , Kinetics , Lasers , Models, Chemical , Muramidase/metabolism , Oxidation-Reduction/drug effects , Oxidation-Reduction/radiation effects , Photolysis/drug effects , Photolysis/radiation effects , Solutions , Spectrum Analysis , Time Factors
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