Utilization of 3D printing for an intravital microscopy platform to study the intestinal microcirculation

Intravital microscopy of the intestine is a sophisticated technique that allows qualitative and quantitative in vivo observation of dynamic cellular interactions and blood flow at a high resolution. Physiological conditions of the animal and in particular of the observed organ, such as temperature and moisture are crucial for intravital imaging. Often, the microscopy stage with the animal or the organ of interest imposes limitations on how well the animal can be maintained. In addition, the access for additional oxygen supply or drug administration during the procedure is rather restricted. To address these limitations, we developed a novel intravital microscopy platform, allowing us to have improved access to the animal during the intravital microscopy procedure, as well as improved microenvironmental maintenance. The production process of this prototype platform is based on 3D printing of device parts in a single‐step process. The simplicity of production and the advantages of this versatile and customizable design are shown and discussed in this paper. Our design potentially represents a major step forward in facilitating intestinal intravital imaging using fluorescent microscopy.     

混凝土冻融损伤后的吸水特性

对掺与未掺引气剂的混凝土进行了冻融破坏,通过吸水试验和中子辐射试验,研究了冻融损伤对掺与未掺引气剂混凝土吸水特性的影响.结果表明,中子成像技术能够实现对非透明性混凝.土材料吸水演进过程的可视化观测和定量分析.未掺引气剂的混凝土其抗冻性较差,在10次冻融循环后动弹模量损失14%的情况下,其水分渗透深度约增30%;掺加引气剂后,即使遭受200次冻融循环,混凝土的整体动弹模量也无明显损失,但200次冻融循环后,混凝土表层出现部分剥落,水分渗透速率及深度均相应增大.在评价混凝土冻融损伤时.除整体动弹模量损失外,还需考虑冻融损伤对混凝土吸水性能的影响.     

Visualization and quantification of water movement in porous cement-based materials by real time thermal neutron radiography:Theoretical analysis and experimental study

Water movement in porous cement-based materials is of great importance when studying their deterioration processes and durability.Many traditional methods based on mass changes,electricity or nuclear magnetic resonances are available for studying water transport in cement-based materials.In this research,an advanced technique i.e.thermal neutron radiography was utilized to achieve visualization and quantification of time dependent water movement including water penetration and moisture vapor in porous cemen...     

Continuous Dyeing of Fabrics by the One-bath ‘Extended-time’ Pad–Steam Process

The continuous dyeing of fabrics by padding and then passage through steamers of large capacity for 2–10 min is described. The thermodynamics of the process are considered, and dyeing plants (Küsters and Gerber) in current use are discussed. Recommendations are given for the conditions for dyeing nylon–cotton plush, acrylic-cotton plush, lining materials, etc. The extended-time steaming process has found a permanent place among the various continuous dyeing processes.     

MOMS-02 sensor simulation and spectral band selection

Abstract

MOMS-02 is a push-broom scanner with four spectral bands in the 450–810 nm region (each with a 15 m ground resolution element at a 310 km orbit) and a panchromatic (520–760 nm) stereo mode with on-track stereoscopic capability. The stereo mode employs three look angles: nadir (with a 5 m ground resolution element), 24° forward and backward (each with a 10 m ground resolution element). The sensor which is funded by the German Ministry for Research and Technology (BMFT) is scheduled for launch on a Space Shuttle mission at the end of 1991. The selection and radiometric performance of the panchromatic and the multispectral bands are discussed.     

Thermostatic tissue platform for intravital microscopy: 'the hanging drop' model

Intravital microscopy imposes the particular problem of the combined control of the body temperature of the animal and the local temperature of the observed organ or tissues. We constructed and tested, in the rat ileum microcirculation preparation, a new organ‐support platform. The platform consisted of an organ bath filled with physiological solution, and contained a suction tube, a superfusion tube, an intestine‐support hand that was attached to a micromanipulator and a thermometer probe. To cover the intestine we used a cover glass plate with a plastic ring glued on its upper surface. After a routine procedure (anaesthesia, monitoring and surgery), the intestine segment (2–3 cm long) was gently exteriorized and placed on the ‘hand’ of the organ support. A small part of the intestine formed a small ‘island’ in the bath that was filled with physiological salt solution. The cover glass was secured in place. The physiological salt solution from the superfusion tube, which was pointed to the lower surface of the cover glass, formed a ‘hanging drop’. The objective of the microscope was then immersed into distilled water that was formed by the cover glass plastic ring. The ‘hanging drop’ technique prevented any tissue quenching, ensured undisturbed microcirculation, provided for stable temperature and humidity, and permitted a clear visual field.     

Noninvasive assessment of the iridial microcirculation in rats using sidestream dark field imaging

Sidestream dark field imaging represents a novel, noninvasive method to study the microcirculation in humans and animals. To‐date, it has been used extensively in various peripheral tissues (e.g. sublingual area, intestinal mucosa), however no data for the ocular vasculature, including the iridial microcirculation, are currently available. Therefore, the aim of this study was to examine the reliability and reproducibility of sidestream dark field imaging within the iridial microcirculation in experimental animals. Male Lewis rats were anaesthetized and the iris microvasculature was observed using an sidestream dark field probe gently placed against a cover slip covering the right eye. All video sequences recorded were analysed off‐line by using AVA 3.0 software (MicroVision Medical, Amsterdam, The Netherlands). Results are expressed as mean (±SE) or median (interquartile range). Clear images were recorded from each animal and the total number of analysable video sequences was 50. All raw data for selected vessel density parameters passed normality test. The total all and small vessel density (in mm mm^‐2) were 22,6 (±0,58) and 19,6 (±0,68), respectively. The perfused all and small vessel density were 20,9 (±0,61) and 19,1 (±0,65), respectively. The mean values of all iris vessel density parameters are shown in Figure 4 . The DeBacker Score (n/mm) was 15,2 (±0,45), the proportion of perfused vessel was 94,5% (89,8–99,1%), and the MFI was 3 points (3–3). Taken together, these results indicate that SDF imaging provides a reliable and noninvasive method to examine the iridial microvascular bed in vivo and, thus, may provide unique opportunities for the study of the iridial vascular network in various experimental and clinical settings and disease models.

Figure 4 Open in figure viewer PowerPoint Vessel Density. TAVD = Total all vessel density; PAVD = Perfused all vessel density; TSVD = Total small vessel density; PSVD = Perfused small vessel density. Data are shown as a mean (±SE), small vessels are referred to diameter ≤ 25 um.