MnFe2O4/polyaniline/diatomite composite with multiple loss mechanisms towards broadband absorption.

The research and development of absorbing materials with high absorbing capacity, wide effective absorption bandwidth, and lightweight has always been interesting. In this research, a facile hydrothermal method was used to prepare MnFe2O4, and the grain size of MnFe2O4 decreased with increasing hydrothermal temperature. When the size of MnFe2O4 nanoparticles is less than 10 nm, its quantum size effect and surface effect make its electromagnetic microwave absorption performance greatly optimized. When the thickness of MnFe2O4-110 °C is 2.57 mm, the minimum reflection loss (RLmin) is -35.28 dB. Based on this, light porous diatomite and a three-dimensional polyaniline network are introduced. Diatomite is used as the base material to effectively reduce the agglomeration of MnFe2O4 quantum dots. The relatively high surface area introduced by a three-dimensional network of polyaniline promotes the orientation, interfacial polarization, multiple relaxation, and impedance matching, thereby generating further dielectric loss. Additionally, the magnetic properties of manganese ferrite and the strong electrical conductivity of polyaniline play an appropriate complementary role in electromagnetic wave absorption. The RLmin of MnFe2O4/PANI/diatomite is -56.70 dB at 11.12 GHz with an absorber layer thickness of 2.57 mm. The effective frequency bandwidth (RL < -10 dB) ranges from 9.21 to 18.00 GHz. The absorption mechanism indicates that the high absorption intensity is the result of the synergistic effect of impedance matching, conduction losses, polarization losses, and magnetic losses.

[Sesamin Preconditioning Attenuates Myocardial Ischemia Reperfusion Injury in Rats Through Activation of Akt/eNOS Signaling Pathway].

Objective: To investigate the protective effect of sesamin on myocardial ischemia reperfusion injury in rats, and to study the possible mechanism. Methods: 50 SD rats were randomly divided into control group, sham operated group, model group, high-dose sesamin group( 160 mg / kg) and low-dose sesamin group( 80 mg / kg),with 10 rats in each group. Rats in sesamin groups were administered intragastrically with sesamin for 7 d. Then all rats except those in sham operated group were subjected to myocardial ischemia-myocardial ischemia reperfusion injury model by coronary artery ligation for 40 min and subsequent reperfusion for 120 min. Serum cardiac troponin Ⅰ( c TnⅠ) and lactate dehydrogenase( LDH),levels of total antioxidant capacity( TAOC) and nitric oxide( NO) in serum and myocardial tissues,Caspase-3 activity in myocardial tissues were detected by colorimetric assay. Cardiomyocyte apoptosis was evaluated by TUNEL assay. Phosphorylation level of endothelial nitric oxide synthase( eNOS) and Protein kinase B( Akt), protein expression of superoxide dismutase( SOD) in cardiac tissue were determined by Western blot. Results: Pretreatment with sesamin significantly ameliorated myocardial injury in rats which induced myocardial ischemia and reperfusion injury by reduced levels of serum c TnⅠand LDH( P <0. 05 or P < 0. 01). Supplementation with sesamin resulted in a significant increasing of total antioxidant capacity and NO level in serum and myocardial tissues and cardiomyocyte apoptosis( P < 0. 05 or P < 0. 01),and remarkable decrease the Caspase-3 activity in myocardial tissues and cardiomyocyte apoptosis( P < 0. 05 or P < 0. 01). Sesamin significantly up-regulated the protein expression of SOD in cardiac tissues, and the levels of phosphorylated eNOS and Akt increased notably( P < 0. 05 or P < 0. 01). Conclusion: Pretreatment with sesamin effectively ameliorated myocardial ischemia reperfusion injury in rats, and the mechanism might be related to enhancing its antioxidant capacity and the activation of Akt / eNOS signaling pathway and subsequent increase of NO synthesis and suppression of cardiac myocyte apoptosis.

[The effect of Salvianolic Acid B on the Apoptosis of HUVECs Induced by Intermittent High Glucose].

Objective: To investigate the effect of Salvianolic acid B (Sal B) on the apoptosis of human umbilical vein endothelial cells (HUVECs) induced by intermittent high glucose and to explore the possible mechanisms. Methods: HUVECs were preincubated with Sal B for 24 h, followed by incubation with intermittent high glucose (IHG, 5.5 mmol/L 12 h, 33.3 mmol/L 12 h) for 72 h. The viability of the HUVECs was determined by MTT assay, and the cells apoptosis was measured flow cytometry, respectively. The levels of nitric oxide (NO), total antioxidant capacity (T-AOC), malondialdehyde (MDA), and Caspase-3 activity were determined by colorimetric method. Intracellular ROS was evaluated by fluorescent microscopy. The protein levels of NOX4, p-eNOS, BAX, and BCL-2 were determined by Western-blot. Results: Pretreatment with Sal B significantly ameliorated IHG-induced cells injury as was manifested by increased cell viability, up-regulated eNOS activation, and promoted the release of NO in HUVECs (P < 0.05 or P < 0.01). Sal B evidently suppressed IHG-induced cell apoptosis, down-regulated the expression of BAX protein and up-regulated the expression of BCL-2 protein. The activity of Capase-3 was also significantly reduced. Pre-incubation with Sal B led to a significant enhancement of antioxidant capacity and a reduction of NOX4 protein expression, accompanied by a remarkable decrease of intracellular ROS and MDA content (P < 0.05 or P < 0.01). Conclusion: Sal B is capable of suppressing IHG-induced injury and apoptosis in HUVECs, which might be attributed to the attenuation of oxidative stress, regulation of BCL-2/BAX protein expression, and subsequent suppression of Caspase-3 activity.

[Effect of Danzhi Jiangtang Capsule on Myocardial Fibrosis in Diabetic Rats].

OBJECTIVE: To investigate the effect of Danzhi Jiangtang Capsule on myocardial fibrosis in diabetic rats with fluctuated blood glucose and the possible mechanisms implicated. METHODS: Following induction of diabetes with intraperitoneal injection of streptozotocin (STZ), rats were administered with insulin or glucose at different time during a day to induce blood glucose fluctuation. After treatment with Danzhi Jiangtang Capsule for six weeks, rats were sacrificed and the hearts were collected for the determination of cardiac mass index. Cardiac levels of angiotensin II (Ang II), type I and type III collagens and transforming growth factor-ß1 (TGF-ß1) were assayed by ELISA. Levels of Smad3 phosphorylation and protein expression of matrix metalloproteinase-2 ( MMP-2) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) were determined by Western blot analysis. Total antioxidant capacity and malondialdehyde (MDA) content in cardiac tissues were measured colorimetrically. RESULTS: Treatment with Danzhi Jiangtang Capsule for six weeks significantly reduced cardiac mass index and cardiac levels of type I and type III collagens (P < 0.05 or P < 0.01). Levels of Ang II, TGF-ß1 and Smad3 phosphorylation in cardiac tissues were also decreased markedly (P < 0.05 or P < 0.01). Supplementation with Danzhi Jiangtang Capsule resulted in an evident up-regulation of MMP-2 protein and down-regulation of TIMP-2 protein expression in cardiac tissues (P < 0.05 or P < 0.01). In addition, Danzhi Jiangtang Capsule significantly enhanced total antioxidant capacity in diabetic rats, while cardiac content of MDA was decreased markedly( P < 0.05 or P < 0.01). CONCLUSION: Danzhi Jiangtang Capsule significantly ameliorated myocardial fibrosis in diabetic rats with fluctuated blood glucose, which might be derived from enhancement of antioxidant capacity, suppression of RAS and TGF-ß1/Smad3 signaling pathway and regulation of MMP-2/TIMP-2 protein expression.

[Effect of Serum Containing Sesamin on Angiotensin II-Induced Apoptosis in Rat Cardiomyocytes].

OBJECTIVE: To investigate the effect of serum containing sesamin on angiotension II (Ang II)-induced apoptosis in rat cardiomyocytes and the possible mechanisms. METHODS: H9c2 rat cardiomyocytes were preincubated with serum containing sesamin or blank serum for 12 h, followed by incubation with Ang II for 24 h. Cell viability was assessed by MTT assay and cell apoptosis was evaluated by flow cytometric analysis. Protein expression of BCL-2, BAX, Caspase-3, p47phox and superoxide dismutase (SOD) was determined by Western blot analysis. Levels of intracellular reactive oxygen species (ROS), total antioxidant capacity (T-AOC) and malondialdehyde (MDA) were measured colorimetrically. RESULTS: Preincubation with serum containing sesamin significantly improved cell viability and suppressed cell apoptosis in H9c2 rat cardiomyocytes exposed to Ang II (P < 0.05 or P < 0.01), with the expression of BAX, Caspase-3 and p47phox protein down-regulated and BCL-2 and SOD protein up-regulated markedly (P < 0.05 or P < 0.01). The levels of T-AOC were effectively increased in serum containing sesamin groups, while the levels of intracellular ROS and MDA contents were decreased significantly (P < 0.05 or P < 0.01). Control serum had no influence on the above mentioned measurements. CONCLUSION: Sesamin is capable of suppressing Ang II-induced apoptosis in H9c2 rat cardiomyocytes, which might be derived, at least partly, from amelioration of oxidative stress, regulation of BAX/BCL-2 protein expression and suppression of Caspase-3 protein expression.

Enhanced chemiluminescence of the luminol-AgNO3 system by Ag nanoparticles.

The oxidation reaction of luminol with AgNO(3) can produce chemiluminescence (CL) in the presence of silver nanoparticles (NPs) in alkaline solution. Based on the studies of UV-vis absorption spectra, photoluminescence (PL) spectra and CL spectra, a CL enhancement mechanism is proposed. The CL emission spectrum of the luminol-AgNO(3)-Ag NPs system indicated that the luminophore was still 3-aminophthalate. On injection of silver nanoparticles into the mixture of luminol and AgNO(3), they catalysed the reduction of AgNO(3) by luminol. The product luminol radicals reacted with the dissolved oxygen, to produce a strong CL emission. As a result, the CL intensity was substantially increased. Moreover, the influences of 18 amino acids, e.g. cystine, tyrosine and asparagine, and 25 organic compounds, including gallic acid, tannic acid and hydroquinone, on the luminol-AgNO(3)-Ag NPs CL system were studied by a flow-injection procedure, which led to an effective method for detecting these compounds.

Salvianolic acid B inhibits the progression of liver fibrosis in rats via modulation of the Hedgehog signaling pathway.

Salvianolic acid B (Sal B) has previously reported anti-hepatic fibrosis effects, though it is not clear if it can inhibit hepatic fibrosis by regulating the hedgehog (Hh) signaling pathway. The aim of the present study was to explore the roles and mechanism of Sal B in preventing and treating liver fibrosis in rats. The study also aimed to determine the role of the Hh signaling pathway in this process. A rat model of liver fibrosis was induced through the subcutaneous injection of 50% carbon tetrachloride, followed by treatment with Sal B. After gavage, blood was collected to detect serum markers of liver injury. The degree of liver fibrosis and tissue damage was assessed using histopathological analysis. Western blotting and reverse transcription-quantitative PCR were used to detect the expression levels of TGF-ß1 and Hh signaling pathway-related genes, including Sonic hedgehog (Shh) protein, membrane protein receptor protein patched homolog 1 (Ptch1), membrane protein receptor Smoothened (Smo) and transcription factor glioma-associated oncogene homolog 1 (Gli1). Serum alanine aminotransferase, aspartate aminotransferase and total bilirubin levels were decreased, whilst levels of albumin were increased in rats with liver fibrosis that were treated with Sal B (P<0.05). Additionally, significant increases in TGF-ß1, Shh, Ptch1, Smo, Gli1 and α-smooth muscle actin expression levels were observed in the liver tissues of rats with hepatic fibrosis (P<0.05). However, Sal B treatment significantly reduced the expression levels of these proteins (P<0.05). In conclusion, the results of the present study suggested that the Hh signaling pathway may be activated during the process of rat liver fibrosis. Thus, Sal B may exert its anti-hepatic fibrosis effects, at least in part, by inhibiting the activation of the Hh signaling pathway.

Salvianolic acid B inhibits intermittent high glucose-induced INS-1 cell apoptosis through regulation of Bcl-2 proteins and mitochondrial membrane potential.

Blood glucose fluctuations, also referred to as intermittent high glucose, have been validated to be more harmful than sustained high glucose in exacerbating pancreatic dysfunction by inducing ß cell apoptosis. Salvianolic acid B (Sal B), an aqueous component of Salvia miltiorrhiza, has been proved beneficial to pancreatic islet function in diabetes, but the underlying mechanisms remain to be elucidated. The present study investigated the protective effect of Sal B on INS-1 cells exposed to intermittent high glucose and the possible mechanisms implicated. The results indicated that Sal B was able to restore cell viability and suppress INS-1 cell apoptosis induced by intermittent high glucose. Preincubation with Sal B led to a significant decrease of caspase-9 and caspase-3 activity and poly ADP-ribose polymerase (PARP) cleavage. Exposure to intermittent high glucose induced significant up-regulation of proapoptotic proteins, down-regulation of antiapoptotic protein and depolarization of mitochondrial membrane potential (MMP) in INS-1 cells, while these changes were reversed effectively in Sal B treated groups. In addition, Sal B markedly attenuated intermittent high glucose-induced oxidative stress as manifested by notably decreased levels of intracellular reactive oxygen species and malondialdehyde (MDA). Taken together, these results indicate that Sal B is able to suppress intermittent high glucose-induced INS-1 cell apoptosis, which might be ascribed to regulation of Bcl-2 family protein expression and preservation of mitochondrial membrane potential.

Effects of Taohongsiwu decoction on the expression of α-SMA and TGF-ß1 mRNA in the liver tissues of a rat model of hepatic cirrhosis.

The present study aimed to explore the treatment effects of Taohongsiwu decoction on the liver fibrosis in a rat model, as few prior studies have investigated the anti-fibrotic effects of Taohongsiwu decoction. High-performance liquid chromatography was used to measure the concentration of ferulic acid and hydrosafflower flavin A in the decoction. Male Sprague-Dawley rats were randomly divided into control, model, colchicine (positive group), Taohongsiwu-high, Taohongsiwu-moderate and Taohongsiwu-low groups; 50% carbon tetrachloride (CCl4) of peanut oil solution was subcutaneously injected to the rats except for the control group, and the drugs were intragastrically administered (10 ml/kg) starting at week 7 for 6 continuous weeks. The rats were deprived of food but not water for 12 h following the final administration, then blood was collected from the abdominal aorta. The liver tissues were obtained, fixed with 10% neutral formaldehyde, and embedded with paraffin. The concentrations of ferulic acid and hydroxysafflor flavin A in Taohongsiwu decoction were 0.12 and 0.57 mg/ml, respectively. The three groups treated with Taohongsiwu decoction were found with significantly lower serum levels of aspartate aminotransferase, alanine amino transferase, collagen IV and hyaluronic acid, as well as higher level of albumin (ALB); in addition, the expression levels of α-smooth muscle actin (α-SMA) and transforming growth factor-ß1 (TGF-ß1) mRNA and collagen I were significantly downregulated. Taohongsiwu decoction improved the liver function, reduced the collagen deposition in the serum and liver tissues, and inhibited the expression of α-SMA and TGF-ß1.

Salvianolic acid B improves vascular endothelial function in diabetic rats with blood glucose fluctuations via suppression of endothelial cell apoptosis.

Vascular endothelial cell injury is an initial event in atherosclerosis. Salvianolic acid B (Sal B), a main bioactive component in the root of Salvia miltiorrhiza, has vascular protective effect in diabetes, but the underlying mechanisms remain unclear. The present study investigated the effect of Sal B on vascular endothelial function in diabetic rats with blood glucose fluctuations and the possible mechanisms implicated. The results showed that diabetic rats developed marked endothelial dysfunction as exhibited by impaired acetylcholine induced vasodilation. Supplementation with Sal B resulted in an evident improvement of endothelial function. Phosphorylation (Ser 1177) of endothelial nitric oxide synthase (eNOS) was significantly restored in Sal B treated diabetic rats, accompanied by an evident recovery of NO metabolites. Sal B effectively reduced vascular endothelial cell apoptosis, with Bcl-2 protein up-regulated and Bax protein down-regulated markedly. Treatment with Sal B led to an evident amelioration of oxidative stress in diabetic rats as manifested by enhanced antioxidant capacity and decreased contents of malondialdehyde in aortas. Protein levels of NOX2 and NOX4, two main isoforms of NADPH oxidase known as the major source of reactive oxygen species in the vasculature, were markedly decreased in Sal B treated groups. In addition, treatment with Sal B led to an evident decrease of serum lipids. Taken together, this study indicates that Sal B is capable of improving endothelial function in diabetic rats with blood glucose fluctuations, of which the underlying mechanisms might be related to suppression of endothelial cell apoptosis and stimulation of eNOS phosphorylation (Ser 1177).