Magic electron affection in preparation process of silicon nanocrystal

Streptozotocin-induced diabetic cardiomyopathy in rats: ameliorative effect of PIPERINE via Bcl2, Bax/Bcl2, and caspase-3 pathways

The objective of present investigation was to appraise the effects of piperine on STZ-induced diabetic cardiomyopathy in rats. Diabetes was induced in Sprague-Dawley rats with intraperitoneal STZ injection, and the rats were assigned to seven groups. Electrocardiograph, hemodynamic, various biochemical, molecular, and histological parameters were examined. Treatment with piperine significantly (p < 0.05) restored altered myocardial functions, inhibited cardiac marker, and restored electrocardiogram and hemodynamic alterations. The elevated level of cardiac oxido-nitrosative stress and decreased cardiac Na-K-ATPase concentration, after STZ administration, were significantly (p < 0.05) attenuated by piperine treatment. Piperine also considerably (p < 0.05) increased myocardial mitochondrial enzyme activity. STZ-induced alteration in heart ANP, BNP, cTn-I, Bcl2, Bax/Bcl2, and caspase3 mRNA expression was significantly (p < 0.05) restored by piperine treatment. Piperine administration reduced histopathological aberrations induced by STZ. In conclusion, the present investigation suggests that piperine ameliorates STZ-induced diabetic cardiomyopathy via modulation of caspase-3, Bcl2, Bax/Bcl2 pathways. Abbreviations: ACE: Angiotensin-Converting Enzyme; ANOVA: Analysis of Variance; ANP: Atrial Natriuretic Peptide; APAF: Apoptotic Protease-Activating Factor; ARB: Angiotensin Receptor Blockers; ATP: Adenosine Triphosphate; Bax: Bcl-2-associated X protein; Bcl2: B-cell lymphoma 2; BPM: Beats Per Minute; BNP: brain natriuretic peptide; CAD: Caspase-3-Activated DNase; cDNA: Complementary DNA; CK-MB: Creatine Kinase-MB; CPCSEA: Committee for the Purpose of Control And Supervision of Experiments on Animals; cTn-I: cardiac troponin I; DBP: Diastolic Blood Pressure; DCM: Diabetic Cardiomyopathy; DNA: Deoxyribonucleic Acid; DPX: DisterenePhthalate Xylene; ECG: Electrocardiogram; ETC: Electron Transport Chain; GOD-POD: Glucose Oxidase Peroxidase; GSH: Glutathione; IAEC: Institutional Animal Ethics Committee; IL-6: Interleukin-6; IL-1b: Interleukin-1b; LDH: Lactate Dehydrogenase; LV: Left Ventricle; LVEDP: left ventricular end-diastolic Pressure; MABP: Mean Arterial Blood Pressure; MDA: Malondialdehyde; mRNA: Messenger Ribonucleic Acid; MTT: 3- (4,5-Dimethylthiazol-2-yl)-2,5-DiphenyltetrazoliumBromide; NADH: Nicotinamide Adenine Dinucleotide Phosphate; NADPH: Nicotinamide Adenine Dinucleotide Phosphate Hydrogen; NO: nitric oxide; NP: Natriuretic Peptides; OXPHOS: Oxidative Phosphorylation; p.o.: per os; PCR: Polymerase Chain Reaction; RT-PCR: Reverse Transcriptionpolymerase Chain Reaction; PPAR: Peroxisome Proliferator-Activated Receptor Gamma; RAS: Renin-Angiotensin System; RNA: Ribonucleic Acid; ROS: Reactive Oxygen Species; SBP: Systolic Blood Pressure; SDH: Succinate Dehydrogenase; SEM: Standard Error Means; SOD: superoxide dismutase: STZ: Streptozotocin; TNF: Tumor Necrosis Factor Alpha; TnI: Troponin I.

Abrupt Change Effect of Bandgap Energy on Quantum System of Silicon Nanowire

In the quantum system of Si nanowire (NW), the energy bandgap obviously increases with decreasing radius size of NW, in which the quantum confinement (QC) effect plays a main role. Furthermore, the simulation result demonstrated that the direct bandgap can be obtained as the NW diameter is smaller than 3 nm in Si NW with (001) direction. However, it is discovered in the simulating calculation that the QC effect disappears as the NW diameter arrives at size of monoatomic line, in which its bandgap sharply deceases where the abrupt change effect in bandgap energy occurs near the idea quantum wire. In the experiment, we fabricated the Si NW structure by using annealing and pulsed laser deposition methods, in which a novel way was used to control the radius size of Si NW by confining cylinder space of NW in nanolayer. It should have a good application on optic-electronic waveguide of silicon chip.

Considerable knock-on displacement of metal atoms under a low energy electron beam

Under electron beam irradiation, knock-on atomic displacement is commonly thought to occur only when the incident electron energy is above the incident-energy threshold of the material in question. However, we report that when exposed to intense electrons at room temperature at a low incident energy of 30 keV, which is far below the theoretically predicted incident-energy threshold of zirconium, Zircaloy-4 (Zr-1.50Sn-0.25Fe-0.15Cr (wt.%)) surfaces can undergo considerable displacement damage. We demonstrate that electron beam irradiation of the bulk Zircaloy-4 surface resulted in a striking radiation effect that nanoscale precipitates within the surface layer gradually emerged and became clearly visible with increasing the irradiation time. Our transmission electron microscope (TEM) observations further reveal that electron beam irradiation of the thin-film Zircaly-4 surface caused the sputtering of surface α-Zr atoms, the nanoscale atomic restructuring in the α-Zr matrix, and the amorphization of precipitates. These results are the first direct evidences suggesting that displacement of metal atoms can be induced by a low incident electron energy below threshold. The presented way to irradiate may be extended to other materials aiming at producing appealing properties for applications in fields of nanotechnology, surface technology, and others.

Lasing with Pumping Levels of Si Nanocrystals on Silicon Wafer

It is reported that the silicon nanocrystals (NCs) are fabricated by using self-assembly growth method with the annealing and the electron beam irradiation processes in the pulsed laser depositing, on which the visible lasing with higher gain (over 130 cm^-1) and the enhanced emission in optical telecommunication window are measured in photoluminescence (PL). It is interesting that the enhanced visible electroluminescence (EL) on silicon nanocrystals (Si-NCs) is obviously observed by the naked eyes, and the light-emitting diode (LED) of the Si-NCs with external quantum efficiency of 20% is made on silicon chip in our laboratory. A four-level system is built for emission model in nanosilicon, in which the PL and EL measurement and transmission electron microscope (TEM) analysis demonstrate that the pumping levels with shorter lifetime from the rising energy of the Si quantum dots due to the quantum confinement effect occur, and the electronic localized states with longer lifetime owing to impurities bonding on Si-NCs surface are formed in the crystallized process to produce the inversion of population for lasing, where the optical gain is generated.

Enhanced Emission of Quantum System in Si-Ge Nanolayer Structure

It is very interesting that the enhanced peaks near 1150 and 1550 nm are observed in the photoluminescence (PL) spectra in the quantum system of Si-Ge nanolayer structure, which have the emission characteristics of a three-level system with quantum dots (QDs) pumping and emission of quasi-direct-gap band, in our experiment. In the preparing process of Si-Ge nanolayer structure by using a pulsed laser deposition method, it is discovered that the nanocrystals of Si and Ge grow in the (100) and (111) directions after annealing or electron beam irradiation. The enhanced PL peaks with multi-longitudinal-mode are measured at room temperature in the super-lattice of Si-Ge nanolayer quantum system on SOI.

Emission of direct-gap band in germanium with Ge-GeSn layers on one-dimensional structure

In our experiment, it was observed that the emission of direct-gap band in germanium with Ge-GeSn layers on one-dimensional (1D) structure. The results of experiment and calculation demonstrate that the uniaxial tensile strain in the (111) and (110) direction can efficiently transform Ge to a direct bandgap material with the bandgap energy useful for technological application. It is interested that under the tensile strain from Ge-GeSn layers on 1D structure in which the uniaxial strain could be obtained by curved layer (CL) effect, the two bandgaps E_Γg and E_Lg in the (111) direction become nearly equal at 0.83 eV related to the emission of direct-gap band near 1500 nm in the experiments. It is discovered that the red-shift of the peaks from 1500 nm to 1600 nm occurs with change of the uniaxial tensile strain, which proves that the peaks come from the emission of direct-gap band.

Luminescence from nearly isolated surface defects in silica nanoparticles

A structured emission/excitation pattern, proper of isolated defects, arises in a vacuum from silica nanoparticles. The luminescence, centered around 3.0-3.5 eV, is characterised by a vibronic progression due to the phonon coupling with two localised modes of frequency  ∼1370 cm(-1) and  ∼360 cm(-1), and decays in about 300 ns at 10 K. On increasing the temperature, the intensity and the lifetime decrease due to the activation of a non-radiative rate from the excited state. Concurrently, the temperature dependence of the lineshape evidences the low coupling with non-localised modes of the matrix (Huang-Rhys factor S ~ 0.2) and the poor influence of the inhomogeneous broadening. These findings outline an uncommon behaviour in the field of the optical properties of defects in amorphous solids, evidencing that the silica surface can allocate luminescent defects almost disentangled from the basal network.