Fine structural analysis of the fibrillar adhesion apparatus in ladybird beetle

The attachment system on the ladybird beetle Harmonia axyridis is composed of a pair of pretarsal claws and adhesive pads at the tarsal segments. The claws, which are connected to the pretarsal segment, are mainly used to hold the rough substrates by their apical diverged hooks. In contrast, the adhesive pads have an adhesive function when landing on smooth surfaces. They are interspersed at the ventral adhesive pad of each tarsomere, and are composed of two kinds of hairy setae. The discoid tip seta (DtS) is located at the central region of each adhesive pad. The DtS has a spoon‐shaped endplate with a long and narrow shaft. In contrast, the pointed tip seta (PtS) is interspersed along the marginal regions of each adhesive pad, and has a hook‐shaped spine near the tip. In the present study, we found numerous fine cuticular pores beneath the setae, which seem to be related to the secretion of some adhesive fluids. It may be deduced that ladybird beetles can attach to smooth surfaces more effectively by employing adhesive fluids filling in surface crevices to overcome problems cause by their larger size endplates.     

Performing and Processing FNA of Anterior Fat Pad for Amyloid

Historically, heart, liver, and kidney biopsies were performed to demonstrate amyloid deposits in amyloidosis. Since the clinical presentation of this disease is so variable and non-specific, the associated risks of these biopsies are too great for the diagnostic yield. Other sites that have a lower biopsy risk, such as skin or gingival, are also relatively invasive and expensive. In addition, these biopsies may not always have sufficient amyloid deposits to establish a diagnosis. Fat pad aspiration has demonstrated good clinical correlation with low cost and minimal morbidity. However, there are no standardized protocols for performing this procedure or processing the aspirated specimen, which leads to variable and nonreproducible results. The most frequently utilized modality for detecting amyloid in tissue is an apple-green birefringence on Congo red stained sections using a polarizing microscope. This technique requires cell block preparation of aspirated material. Unfortunately, patients presenting in early stage of amyloidosis have minimal amounts of amyloid which greatly reduces the sensitivity of Congo red stained cell block sections of fat pad aspirates. Therefore, ultrastructural evaluation of fat pad aspirates by electron microscopy should be utilized, given its increased sensitivity for amyloid detection. This article demonstrates a simple and reproducible procedure for performing anterior fat pad aspiration for the detection of amyloid utilizing both Congo red staining of cell block sections and electron microscopy for ultrastructural identification.     

Tribological Behavior of Gampsocleis Gratiosa Foot Pad Against Vertical Flat Surfaces

Some tribological behavior between mature Gampsocleis gratiosa foot pads and vertical flats of different materials were studied in this work. stereomicroscope （SMS） and scanning electron microscope （SEM） were used to measure the morphology of the Gampsocleis gratiosa foot pads. An atomic force microscope （AFM） was used to measure the morphologies of the surfaces of glass and a wall doped with calcium carbonate material. The attaching behavior of Gampsocleis gratiosa feet on the two vertical surfaces was observed. The attaching force （perpendicular to the vertical surface） and the static frictional force （along the direction of gravitation） of Gampsocleis gratiosa foot pads on a vertical glass were measured. It was shown that the average attaching force is 50.59 mN and the static frictional force is 259.10 mN. The physical models of the attaching interface between Gampsocleis gratiosa foot pads and the two vertical surfaces were proposed. It was observed that the foot pads are smooth in macroscale; however, the pad surface is composed by approximate hexagonal units with sizes of 3 μm to 7 μm in microscale; the adjacent units are separated by nanoscale grooves. The Observations showed that the Gampsocleis gratiosa can not climb the vertical calcium carbonate wall; in contrast, they can easily climb the vertical glass surface. Based on the features of the geometrical morphologies of the foot pads and the glass surface, we speculate that the attaching force and strong static frictional force are attributed to the interinlays between the deformable Gampsocleis gratiosa foot pads and the nanoscale sharp tips of the glass surface.     

Structural correlates of increased adhesive efficiency with adult size in the toe pads of hylid tree frogs

Tree frogs are able to climb smooth, vertical substrates using specialised toe pads which adhere via an area-based wet adhesive mechanism. Although the link between pads and arboreality in frogs is well-established, few studies have investigated the influence of morphology on adhesion. Trinidadian tree frogs from the genus Hyla are geometrically similar. There is a tendency towards comparatively reduced mass in larger species, but toe pad area increases as expected with isometry. As adhesion is area-dependent, forces are affected directly by the increase in mass relative to pad area, and there is a decrease in the ability of larger species to adhere to smooth rotation platforms. However, there is an increase in force per unit area that suggests larger species have more efficient toe pads. Toe pad structure is very similar though there are variations in the details of a number of features. Crucially, although differences in morphology appeared small they had demonstrable effects on adhesive efficiency of the pads. Epithelial cell area correlates positively with frog length and adhesive efficiency, related features of cell density and intercellular channel length correlate negatively. These findings are discussed in relation to the different forces involved in the tree frogs’ wet adhesive system.     

Histomorphometric comparison after fixation with formaldehyde or glyoxal

Abstract

Formaldehyde has long been the fixative of choice for histological examination of tissue. The use of alternatives to formaldehyde has grown, however, owing to the serious hazards associated with its use. Companies have striven to maintain the morphological characteristics of formaldehyde-fixed tissue when developing alternatives. Glyoxal-based fixatives now are among the most popular formaldehyde alternatives. Although there are many studies that compare staining quality and immunoreactivity, there have been no studies that quantify possible structural differences. Histomorphometric analysis commonly is used to evaluate diseased tissue. We compared fixation with formaldehyde and glyoxal with regard to the histomorphological properties of plantar foot tissue using a combination of stereological methods and quantitative morphology. We measured skin thickness, interdigitation index, elastic septa thickness, and adipocyte area and diameter. No significant differences were observed between formaldehyde and glyoxal fixation for any feature measured. The glyoxal-based fixative used therefore is a suitable fixative for structural evaluation of plantar soft tissue. Measurements obtained from the glyoxal-fixed tissue can be combined with data obtained from formalin-fixed for analysis.     

Constitutive formulation and numerical analysis of the heel pad region

The aim of this work is to provide a numerical approach for the investigation of the mechanical behaviour of the heel pad region. A visco-hyperelastic model is formulated with regard to fat pad tissue, while a fibre-reinforced hyperelastic model is considered for the heel skin tissue. Bone components are defined by means of an orthotropic linear elastic model. Particular attention is paid to the evaluation of constitutive parameters within different models adopted in consideration of experimental tests data. Preliminarily, indentation tests on a skinless cadaveric foot are considered with regard to fat pad tissue. Indentation tests on an intact heel pad of a cadaveric foot are subsequently adopted for the final identification of constitutive parameters of fat pad and skin tissues. A numerical model of the rear foot is defined and different loading conditions are assumed according to experimental data. A comparison between experimental and numerical data leads to the evaluation of the real capability of the procedure to interpret the actual response of the rear foot.     

基于DIG -化学发光法的Southern blot方法优化

目前,基于DIG-化学发光法的Southern blot技术已在生物实验室广泛应用,但在试验过程中经常会遇到背景黑、目的信号弱等问题,以致不能获得理想结果.在棉花线拉体基因组RFLP分析过程中结合前人经验对基于DIG -化学发光法的Southern blot技术在探针标记、探针浓度、探针剥高等方面进行了优化.优化后的方...