Measuring the Three-Dimensional Kinematics of a Free-Swimming Koi Carp by Video Tracking Method

A video tracking system for measuring three-dimensional kinematics of a free-swimming fish is presented. The tracking is accomplished by simultaneously taking images from the ventral view and the lateral view of the fish with two cameras mounted on two computer-controlled and mutually orthogonal translation stages. Compared to the previous system we reported, the time resolution is greatly improved. A koi carp is selected for the experiment. By processing the images caught by the video tracking system, the three-dimensional kinematics of the koi carp during a continuous swimming containing several moderate maneuvers are obtained. In particular, the pitching motion of fish body and the tail motion, including lateral excursion, variation in tail height and torsion, are revealed for burst-and-coast swimming and turning maneuver. The error analysis is also provided for the measurement results.     

A New Histochemical Double-Stain Method Using Three-Dimensional Analysis with Confocal laser Scanning Microscopy

We describe a new technique for immunohistochemical and enzyme-histochemi-cal double staining using confocal laser scanning microscopy in the reflection mode. As an example, we investigated the immunoreactivity for Spot 35-calbindin-D_28K, a vitamin D-dependent calcium binding protein, and the enzyme activity for ma⁺-ATPase in the rat kidney. The lead precipitation method for Ca²⁺-ATPase was initially used to process kidney slices. Each specimen was then dehydrated and embedded in a water soluble resin. Thin sections were cut from the resin block, and an indirect immunocolloidal gold method with silver enhancement for Spot 35-calbindin-D_28K antigen was carried out on the glass slides. Results were then observed by confocal laser scanning microscopy in the reflection mode. The three-dimensional distribution of the reaction products was detected by serial optic slice images. Lead phosphate particles, which represented the location of Ca²⁺-ATPase, were distributed deep in the section. The most intense signals from the silver partkles were detected from the surface slice of the section. A stereoscopic image generated from the serial optic slices clearly showed the differences in their distribution.     

对地贫红细胞的显微激光散射和图象分析

应用显微准弹性激光散射(MQLS)技术与显微生物医学图象分析技术对地中海贫血红细胞及胞内血红蛋白动态特性进行了研究.在实验中,比较了正常人及地贫患者红细胞胞内血红蛋白聚集体的平均流体力学半径、平均平动扩散系数及红细胞膜的搏动频率等动态特性参数,以及细胞的截面积、规化形状因子、长径、短径、灰度等图象分析数据,发现地贫红细胞的血红蛋白聚合物平均流体力学半径远远大于正常人红细胞的,其大小变异亦较正常人大,且其膜搏动频率也较为缓慢,细胞的截面积也变小.这反映了地贫红细胞内有较大的蛋白质聚合物存在和红细胞变形能力差的特性.研究还表明,显微准弹性激光散射技术结合图象分析技术,可使测量的可比性和准确性大大提高,预期可广泛适用于各种活细胞动态特性的研究.     

Shrinkage of Dental Composite in Simulated Cavity Measured with Digital Image Correlation

Polymerization shrinkage of dental resin composites can lead to restoration debonding or cracked tooth tissues in composite-restored teeth. In order to understand where and how shrinkage strain and stress develop in such restored teeth, Digital Image Correlation (DIC) was used to provide a comprehensive view of the displacement and strain distributions within model restorations that had undergone polymerization shrinkage.Specimens with model cavities were made of cylindrical glass rods with both diameter and length being 10 mm. The dimensions of the mesial-occlusal-distal (MOD) cavity prepared in each specimen measured 3 mm and 2 mm in width and depth, respectively. After filling the cavity with resin composite, the surface under observation was sprayed with first a thin layer of white paint and then fine black charcoal powder to create high-contrast speckles. Pictures of that surface were then taken before curing and 5 min after. Finally, the two pictures were correlated using DIC software to calculate the displacement and strain distributions.The resin composite shrunk vertically towards the bottom of the cavity, with the top center portion of the restoration having the largest downward displacement. At the same time, it shrunk horizontally towards its vertical midline. Shrinkage of the composite stretched the material in the vicinity of the “tooth-restoration” interface, resulting in cuspal deflections and high tensile strains around the restoration. Material close to the cavity walls or floor had direct strains mostly in the directions perpendicular to the interfaces. Summation of the two direct strain components showed a relatively uniform distribution around the restoration and its magnitude equaled approximately to the volumetric shrinkage strain of the material.     

Effect of Soil Fabric on Transport of a LNAPL through Unsaturated Fine-Grained Soils: A Centrifugal Model Study

Centrifugal model tests were performed to study the impact of the fabric of a fine-grained soil on transport of a light non-aqueous phase liquid (LNAPL). An image processing technique was developed to extract contaminant transport and fate data from the centrifugal model. Two unconsolidated sites with different moisture contents and a saturated site consolidated due to self-weight were simulated using the centrifuge. The LNAPL migrated in the vertical direction as a narrow plume and formed a free product pool above the saturated zone in unsaturated and unconsolidated soils. However, the LNAPL migrated in the horizontal direction before moving in the vertical direction as a broad plume in the consolidated site. The test results showed that the final width of the plume in the unsaturated zone of the consolidated site was nearly two times as large as that for the unconsolidated sites. In addition, the rate of leak from the underground storage tanks (USTs) on consolidated soils was substantially higher when compared with those on the unconsolidated state. The comparison of LNAPL saturation profiles at the centerline of the centrifugal models during leakage showed that, depending on the soil fabric at a given time and depth, the LNAPL phase would be different; i.e., mobile or immobile (residual) in the same soil type. The test results provided additional insight into contribution of soil fabric on transport and fate of contaminants. The soil fabric controls the geological and hydro-geological properties of fine-grained soils and hence the contamination plume.     

Raman spectroscopy predicts the link between claw keratin and bone collagen structure in a rodent model of oestrogen deficiency

Osteoporosis is a common disease characterised by reduced bone mass and an increased risk of fragility fractures. Low bone mineral density is known to significantly increase the risk of osteoporotic fractures, however, the majority of non-traumatic fractures occur in individuals with a bone mineral density too high to be classified as osteoporotic. Therefore, there is an urgent need to investigate aspects of bone health, other than bone mass, that can predict the risk of fracture. Here, we successfully predicted association between bone collagen and nail keratin in relation to bone loss due to oestrogen deficiency using Raman spectroscopy. Raman signal signature successfully discriminated between ovariectomised rats and their sham controls with a high degree of accuracy for the bone (sensitivity 89%, specificity 91%) and claw tissue (sensitivity 89%, specificity 82%). When tested in an independent set of claw samples the classifier gave 92% sensitivity and 85% specificity. Comparison of the spectral changes occurring in the bone tissue with the changes occurring in the keratin showed a number of common features that could be attributed to common changes in the structure of bone collagen and claw keratin. This study established that systemic oestrogen deficiency mediates parallel structural changes in both the claw (primarily keratin) and bone proteins (primarily collagen). This strengthens the hypothesis that nail keratin can act as a surrogate marker of bone protein status where systemic processes induce changes.     

Analysis of the membrane-associated poly(A)+RNA in the cytoplasm of dormant Artemia cysts by DNA excess hybridization: Evidence for a nuclear origin

Encysted embryos of Artemia contain latent mRNA, to a large extent associated with a fraction of cytoplasmic membranes. The membranes, purified by EDTA treatment and banding in a sucrose gradient at 1.17 g/cm³, include endoplasmic vesicles and mitochondria. The origin of the membrane-associated poly(A)⁺RNA was therefore investigated. In gel electrophoresis poly(A)⁺RNA from the purified membranes of dormant cysts forms two distinct bands at approx. 3·10⁵ and 5·10⁵ Da. Later during development the lighter component decreases. Nuclei from dormant cysts are devoid of poly(A)⁺RNA, while nuclei from developing embryos (50% emergence) contain a predominant poly(A)⁺RNA component of approx. 5·10⁵ Da. ¹²⁵I-labelled preparations of nuclear DNA and of nuclear and membrane-associated poly(A)⁺RNA were used in reassociation and hybridization experiments with excess nuclear DNA. Poly(A)⁺RNA from the membranes of dormant cysts hybridized to nuclear DNA to the same extent as the nuclear poly(A)⁺RNA from developing embryos. The hybridization of labelled, nuclear poly(A)⁺RNA to nuclear DNA was strongly inhibited by unlabelled membrane RNA from either dormant cysts or developing embryos. It is concluded that the stored, membrane-associated poly(A)⁺RNA in dormant cysts is essentially of nuclear origin. The 5·10⁵-Da component is largely homologous with the corresponding component of nuclear poly(A)⁺RNA at later stages.