Terahertz Irradiation Improves Cognitive Impairments and Attenuates Alzheimer's Neuropathology in the APP/PS1 Mouse: A Novel Therapeutic Intervention for Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by the deposition of amyloid-β (Aβ), neurofibrillary tangles, neuroinflammation, and neurodegeneration in the brain. In recent years, considering the unsatisfied benefits of pharmacological therapies, non-pharmacological therapy has become a research hotspot for AD intervention. Terahertz (THz) waves with a range between microwave and infrared regions in the electromagnetic spectrum and high permeability to a wide range of materials have great potential in the bioengineering field.

The vibronic state dependent predissociation of HS: determination of all fragmentation processes.

Photochemistry plays a significant role in shaping the chemical reaction network in the solar nebula and interstellar clouds. However, even in a simple triatomic molecule photodissociation, determination of all fragmentation processes is yet to be achieved. In this work, we present a comprehensive study of the photochemistry of HS, derived from cutting-edge translational spectroscopy measurements of the H, S(D) and S(S) atom products formed by photolysis at wavelengths across the range 155-120 nm.

Photodissociation of HS: A New Pathway for the Production of Vibrationally Excited Molecular Hydrogen in the Interstellar Medium.

Hydrogen sulfide (HS) is the most abundant S-bearing molecule in the solar nebula. Although its photochemistry has been studied for decades, the H fragment channel is still not well-understood. Herein, we describe the photodissociation dynamics of HS + → S(S) + H(XΣ) with the excitation wavelength of 122 nm ≤ λ ≤ 136 nm.

Local pressure calibration method of inductively coupled plasma generator based on laser Thomson scattering measurement.

Based on laser Thomson scattering (TS) measurements and finite element method (FEM) simulations of electron density in inductively coupled plasma (ICP), the simulated local pressure calibration curves of ICP generator are obtained by comparing the experimental and simulated electron density distributions and maxima. The equation coefficients of theoretical model associated with the ICP generator experimental system can be obtained by fitting the simulation curve with the least square method, and the theoretical pressure calibration curves under different absorbed powers can be further obtained. Combined with the vacuum gauge measurements, both the simulated and theoretical pressure calibration curves can give the true local pressure in the plasma.

High resolution laser Thomson scattering system with automatic data analysis software platform for diagnosis of the low-temperature plasmas.

Accurate measurements of electron temperature (T) and electron density (n) are important for understanding the properties of plasma, especially for the low-temperature plasma dominated by the free electrons. In this work, a high resolution laser Thomson scattering (LTS) diagnosis system with a software platform for processing data is established to accurately measure the T and n in low-temperature plasmas. In this system, a homemade Triple Grating Spectrometer (TGS) is elaborated to suppress the intense stray light and Rayleigh scattering light.

Propagation characteristics of terahertz wave in inductively coupled plasma.

Firstly, the electron density distribution of inductively coupled plasma (ICP) is measured by laser Thomson scattering (TS) method and the features of the ICP under the same experimental conditions are simulated by finite element method (FEM). The simulated results are in good agreement with the experimental results, which verifies the accuracy of the ICP generation simulation model. Secondly, the propagation characteristics of terahertz wave in ICP are measured by terahertz time domain spectroscopy (THz-TDS) and calculated by FEM according to the electron density distribution of ICP simulated in the first step above.

Experimental and Computational Studies of Criegee Intermediate -CHCHOO Reaction with Hydrogen Chloride.

Hydrogen chloride (HCl) contributes substantially to the atmospheric Cl; both species could affect the composition of Earth's atmosphere and the fate of pollutants. Here, we present the kinetics study for -CHCHOO reaction with HCl using experimental measurement and theoretical calculations. The experiment was conducted in a flow tube reactor at a pressure of 10 Torr and temperatures ranging from 283 to 318 K by using the OH laser-induced fluorescence (LIF) method.

Rotational and nuclear-spin level dependent photodissociation dynamics of HS.

The detailed features of molecular photochemistry are key to understanding chemical processes enabled by non-adiabatic transitions between potential energy surfaces. But even in a small molecule like hydrogen sulphide (HS), the influence of non-adiabatic transitions is not yet well understood. Here we report high resolution translational spectroscopy measurements of the H and S(D) photoproducts formed following excitation of HS to selected quantum levels of a Rydberg state with B electronic symmetry at wavelengths λ ~ 139.

Water Photolysis and Its Contributions to the Hydroxyl Dayglow Emissions in the Atmospheres of Earth and Mars.

Airglow is a well-known phenomenon in the Earth's upper atmosphere, which arises from the emissions of energetic atoms and molecules. The Meinel band emission from high vibrationally excited OH(X) radicals is one of the more important contributors to the airglow from the mesosphere/lower thermosphere. The H + O reaction has long been regarded as the dominant source of these OH(X, high ) radicals.

Ultraviolet photolysis of HS and its implications for SH radical production in the interstellar medium.

Hydrogen sulfide radicals in the ground state, SH(X), and hydrogen disulfide molecules, HS, are both detected in the interstellar medium, but the returned SH(X)/HS abundance ratios imply a depletion of the former relative to that predicted by current models (which assume that photon absorption by HS at energies below the ionization limit results in H + SH photoproducts). Here we report that translational spectroscopy measurements of the H atoms and S(D) atoms formed by photolysis of jet-cooled HS molecules at many wavelengths in the range 122 ≤ λ ≤155 nm offer a rationale for this apparent depletion; the quantum yield for forming SH(X) products, Γ, decreases from unity (at the longest excitation wavelengths) to zero at short wavelengths. Convoluting the wavelength dependences of Γ, the HS parent absorption and the interstellar radiation field implies that only ~26% of photoexcitation events result in SH(X) products.

Research on the Physio-Biochemical Mechanism of Non-Thermal Plasma-Regulated Seed Germination and Early Seedling Development in .

Non-thermal plasma holds great potentials as an efficient, economical, and eco-friendly seed pretreatment method for improving the seed germination and seedling growth, but the mechanisms are still unclear. Therefore, a plant model organism was used to investigate the physio-biochemical responses of seeds to non-thermal plasma at different treatment times by measuring the plant growth parameters, redox-related parameters, calcium (Ca) level and physicochemical modification of seed surface. The results showed that short-time plasma treatment (0.

Development of an in situ diagnostic system for mapping the deposition distribution on plasma facing components of the HL-2M tokamak.

The assessment of material deposition and fuel retention on Plasma Facing Components (PFCs) is of primary importance for the steady-state operations of future fusion devices. In this paper, an in situ diagnostic for mapping the deposition distribution (IMap) on a wide area of PFCs for HL-2M (Huan Liu Qi-2 Modification) is developed. The design, fabrication, integration, and lab test of the IMap have been implemented.

Comparative study on self-absorption of laser-induced tungsten plasma in air and in argon.

The onset of self-absorption of laser-induced plasma poses a problem for converting emission line intensities to concentrations, which is one of the main bottlenecks in quantitative laser-induced breakdown spectroscopy (LIBS) measurements. In this paper, the effects of atmosphere and laser fluence on self-absorption reduction of the plasma induced on tungsten-copper alloy target were investigated with nanosecond infrared (1064 nm) laser pulse over a range of 2.9 to 18.

Remote in situ laser-induced breakdown spectroscopic approach for diagnosis of the plasma facing components on experimental advanced superconducting tokamak.

The diagnosis of the fuel retention and impurity deposition on the plasma facing components (PFCs) is very important for monitoring plasma-wall interactions and improving the performance of long-pulse operation for tokamak devices. In this study, a remote in situ laser-induced breakdown spectroscopic (RIS-LIBS) system has been developed to be an effective and routine method for the diagnosis of the composition of the PFCs on Experimental Advanced Superconducting Tokamak (EAST). The RIS-LIBS system can be operated between EAST discharges via a remote network control system.

Enhancement of Laser-Induced Breakdown Spectroscopic Signals in a Liquid Jet with Glow Discharge.

In this work, emission signals of laser-induced breakdown (LIBS) plasma of a flowing liquid jet in the absence and presence of an air-supported glow discharge have been investigated. In combination with a needle-to-needle glow discharge, a Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm, 5 ns) with power density ∼10W/cm was used to generate a plasma from a liquid jet. Emission lines of Mg, Ca, Al, Li, Na, and K all showed significant enhancements in the presence of the glow discharge.

A dynamic monitoring approach for the surface morphology evolution measurement of plasma facing components by means of speckle interferometry.

Plasma Facing Components (PFCs) in a magnetically confined fusion plasma device will be exposed to high heat load and particle fluxes, and it would cause PFCs' surface morphology to change due to material erosion and redeposition from plasma wall interactions. The state of PFCs' surface condition will seriously affect the performance of long-pulse or steady state plasma discharge in a tokamak; it will even constitute an enormous threat to the operation and the safety of fusion plasma devices. The PFCs' surface morphology evolution measurement could provide important information about PFCs' real-time status or damage situation and it would help to a better understanding of the plasma wall interaction process and mechanism.

High sensitive and high temporal and spatial resolved image of reactive species in atmospheric pressure surface discharge reactor by laser induced fluorescence.

The current paucity of spatial and temporal characterization of reactive oxygen and nitrogen species (RONS) concentration has been a major hurdle to the advancement and clinical translation of low temperature atmospheric plasmas. In this study, an advanced laser induced fluorescence (LIF) system has been developed to be an effective antibacterial surface discharge reactor for the diagnosis of RONS, where the highest spatial and temporal resolution of the LIF system has been achieved to ∼100 μm scale and ∼20 ns scale, respectively. Measurements on an oxidative OH radical have been carried out as typical RONS for the benchmark of the whole LIF system, where absolute number density calibration has been performed on the basis of the laser Rayleigh scattering method.

Magnetic resonance morphometry of the loss of gray matter volume in Parkinson's disease patients.

Voxel-based morphometry can be used to quantitatively compare structural differences and func-tional changes of gray matter in subjects. In the present study, we compared gray matter images of 32 patients with Parkinson's disease and 25 healthy controls using voxel-based morphometry based on 3.0 T high-field magnetic resonance T1-weighted imaging and clinical neurological scale scores.

High spatial resolution mapping of deposition layers on plasma facing materials by laser ablation microprobe time-of-flight mass spectroscopy.

A laser ablation microprobe time-of-flight mass spectroscopy (LAM-TOF-MS) system with high spatial resolution, ~20 nm in depth and ~500 μm or better on the surface, is developed to analyze the composition distributions of deposition layers on the first wall materials or first mirrors in tokamak. The LAM-TOF-MS system consists of a laser ablation microprobe combined with a TOF-MS and a data acquisition system based on a LabVIEW program software package. Laser induced ablation combined with TOF-MS is an attractive method to analyze the depth profile of deposited layer with successive laser shots, therefore, it can provide information for composition reconstruction of the plasma wall interaction process.

[X-ray diagnostic machine synchronization control on EMC test].

This paper puts forward a new synchronous loading control method using EMC test system & X-ray diagnostic machine in the field of X-ray diagnostic machine on EMC test, solves it's recurrence problem.

Changes of brain gray matter structure in Parkinson's disease patients with dementia.

Voxel-based morphometry is gaining considerable interest for studies examining Parkinson's disease dementia patients. In this study, 12 patients with clinically defined Parkinson's disease and dementia and 12 non-demented patients with Parkinson's disease were examined using a T1WI three-dimensional fast spoiled gradient echo sequence. Gray matter data were analyzed using a voxel-based morphometry method and independent sample t-test based on Statistical Parametric Mapping 5 software.

Calculation of the second self-diffusion and viscosity virial coefficients of Lennard-Jones fluid by equilibrium molecular dynamics simulations.

The second self-diffusion and viscosity virial coefficients of the Lennard-Jones (LJ) fluid were calculated by a detailed evaluation of the velocity and shear-stress autocorrelation functions using equilibrium molecular dynamics simulations at low and moderate densities. Accurate calculation of these coefficients requires corresponding transport coefficient values with low degrees of uncertainty. These were obtained via very long simulations by increasing the number of particles and by using the knowledge of correlation functions in the Green-Kubo method in conjunction with their corresponding generalized Einstein relations.

Laser mass-spectrometry for online diagnosis of reactive plasmas with many species.

The purpose of this study is to design a diagnostic system for reactive plasma environment by combining molecular-beam time-of-flight (TOF) mass spectroscopy with laser spectroscopy technique. The combination of TOF mass spectrometers and pulsed lasers is favorable in the diagnosis of intermediate species distribution since they allow the simultaneous but separate recording of the spectra of different species. In the plasma system, the intermediate species in electronic ground state or low lying excited state is pumped to higher energy level with resonant laser excitation, and then, the ionization with a second laser system is possible which can readily be detected by the TOF analyzer.

Gas phase electronic spectrum of linear AlCCH.

The electronic spectrum of the aluminium containing species AlCCH has been detected in the gas phase in the region 315-355 nm. The experiment used a mass selective resonant two-color two-photon ionization technique coupled to a laser ablation source. Structures of the AlCCH isomers have been optimized using density functional theory (DFT) and the excitation energies to the low-lying electronic excited states calculated.

Resonant two-photon ionization spectroscopy of BNB.

Triatomic BNB has been produced by laser ablation of a boron nitride rod in a supersonic expansion of helium carrier gas and has been investigated using resonant two-photon ionization spectroscopy in the visible region. The B 2Pi(g)-X 2Sigma(u)+ band system has been recorded near 514 nm and is dominated by a strong origin band, which has been rotationally resolved and analyzed. Both the (11)B(14)N(11)B (64% natural abundance) and the (10)B(14)N(11)B (32% natural abundance) isotopic modifications have been analyzed, leading to the spectroscopic constants (and their 1sigma error limits) of B0"(X 2Sigma(u)+)=0.