RESUMO
In order to realize in situ multi-frame framing, this paper designed and developed a large-waist framing converter tube. The size ratio between the waist and the object was about 1.16:1. The subsequent test results showed that the static spatial resolution of the tube could reach 10 lp/mm (@ 72.5%) under the premise of this adjustment, and the transverse magnification could reach 2.9. Once the MCP (Micro Channel Plate) traveling wave gating unit is equipped at the output end, it is expected to promote the further development of in situ multi-frame framing technology.
RESUMO
The development of inertial confinement fusion (ICF) experiments necessitates the diagnostic instrument to have multiple frames with a high spatial and temporal resolution for the two-dimensional detection of the hot spot at the implosion end of the ICF. The existing sampling two-dimensional imaging technology in the world has superior performance; however, its subsequent development requires a streak tube with large lateral magnification. In this work, an electron beam separation device was designed and developed for the first time. The device can be used without changing the structure of the streak tube. It can be combined directly with the corresponding device and matched with a special control circuit. Based on the original transverse magnification, 1.77 times the secondary amplification can be achieved, which is conducive to expanding the recording range of the technology. The experimental results showed that the static spatial resolution of the streak tube after the inclusion of the device can still reach 10 lp/mm.
RESUMO
For an electron-optical imaging system with wide beam focusing, the calculation of the field curvature can be performed only theoretically and requires the specific analytical expressions of the axial potential distribution in the streak tube and its corresponding derivatives, making the calculation cumbersome. Even when the electron trajectory is tracked using the numerical calculation method, the calculated results cannot be verified experimentally. A method for measuring the field curvature of the streak tube based on the spherical fluorescent screen is proposed for the first time, to the best of our knowledge. This method can directly measure the field curvature from the experimental image without requiring information on the internal structure of the streak tube, which is extremely useful for the design of the subsequent image reconstruction algorithm.
RESUMO
A femtosecond x-ray streak camera based on photoelectron filter technology is reported in this paper. Photoelectrons are collimated through the slit and channel of the photoelectron filter, so that transit time spread and space charge effect of electrons are reduced. A planar-focusing high-voltage electron-optical system is designed to match the filter. The channel length of the filter is 300 µm, and the slit width is 20 µm. The streak tube using the photoelectron filter is 273 mm in length, and the extraction field value between the Au photocathode and the filter is 10 kV/mm. An experimental platform is set up to calibrate the streak camera, which is excited by a 266 nm, 130 fs UV laser. The experimental results show that temporal resolution is 357 fs and dynamic range is 182:1 of this developed camera.
RESUMO
Glycation product accumulation during aging of slowly renewing tissues may be an important mechanism underlying aging of the testis. Adipose-derived stem cells (ADSCs) have shown promise in a novel tissue regenerative technique and may have utility in treating sexual dysfunction. ADSCs have also been found to be effective in antiaging therapy, although the mechanism underlying their effects remains unknown. This study was designed to investigate the anti-aging effect of ADSCs in a D-galactose (D-gal)-induced aging animal model and to clarify the underlying mechanism. Randomly selected 6-week-old male Sprague-Dawley rats were subcutaneously injected with D-gal daily for 8 weeks. Two weeks after completion of treatment, D-gal-induced aging rats were randomized to receive caudal vein injections of 3 × 10(6) 5-bromo 2'deoxy-uridine-labeled ADSCs or an equal volume of phosphate-buffered saline. Serum testosterone level, steroidogenic enzymes (3-ß-hydroxysteroid dehydrogenase), and superoxide dismutase (SOD) activity decreased significantly in aging rats compared with the control group; serum lipid peroxidation, spermatogenic cell apoptosis, and methane dicarboxylic aldehyde (MDA) expression increased significantly. ADSCs increased the SOD level and reduced the MDA level in the aging animal model and restored levels of serum testosterone, steroidogenic enzymes, and spermatogenic cell apoptosis. These results demonstrate that ADSCs can contribute to testicular regeneration during aging. ADSCs also provide functional benefits through glycation suppression and antioxidant effects in a rat model of aging. Although some ADSCs differentiated into Leydig cells, the paracrine pathway seems to play a main role in this process, resulting in the reduction of apoptosis.
Assuntos
Tecido Adiposo/citologia , Adiposidade/fisiologia , Envelhecimento/metabolismo , Diferenciação Celular/fisiologia , Células-Tronco/citologia , Doenças Testiculares/terapia , Adipócitos/citologia , Animais , Modelos Animais de Doenças , Feminino , Galactose/farmacologia , Masculino , Ratos Sprague-Dawley , Regeneração , Transplante de Células-Tronco/métodos , Doenças Testiculares/patologiaRESUMO
An eight-frame gated microchannel plate (MCP) camera and a gating electrical pulse are described in this article. The gating electrical pulse is obtained by first generating a high voltage fast step pulse using avalanche transistors in Marx bank configuration, and then shaping it using avalanche diodes. The high voltage fast step pulse is about 200 ps in fall time and 4 kV in amplitude. The gating pulse wave form with width of 160 ps and amplitude of 2.5 kV is achieved. Each frame photocathode coated with gold on the MCP is part of a 12 Omega transmission line with open circuit end driven by the gating electrical pulse. The camera is tested by illuminating its photocathode with ultraviolet laser pulses, 266 nm in wavelength, which shows exposure time as short as 120 ps.
Assuntos
Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Processamento de Sinais Assistido por Computador/instrumentação , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The anatomical basis for the concept of acupuncture points/meridians in traditional Chinese medicine (TCM) has not been resolved. This paper reviews the fascia research progress and the relationship among acupuncture points/meridians, primo vascular system (PVS), and fascia. Fascia is as a covering, with common origins of layers of the fascial system despite diverse names for individual parts. Fascia assists gliding and fluid flow and holds memory and is highly innervated. Fascia is intimately involved with nourishment of all cells of the body, including those of disease and cancer. The human body's fascia network may be the physical substrate represented by the meridians of TCM. The PVS is a newly found circulatory system; recent increased interest has led to new research and new discoveries in the anatomical and functional aspects of the PVS. The fasciology theory provides new insights into the physiological effects of acupuncture needling on basic cellular mechanisms including connective tissue mechanotransduction and regeneration. This view represents a theoretical basis and means for applying modern biomedical research to examining TCM principles and therapies, and it favors a holistic approach to diagnosis and treatment.