scholarly journals SILKS AND SILK-PRODUCING ORGANS OF NEOTROPICAL TARANTULA AVICULARIA METALLICA (ARANEAE, MYGALOMORPHAE, THERAPHOSIDAE)

2016 ◽  
Vol 7 ◽  
pp. 313-327 ◽  
Author(s):  
Jaromír Hajer ◽  
Simona Karschová ◽  
Dana Řeháková

Silks and silk-producing organs of the theraphosid species Avicularia metallica were studied using scanning electron microscopy. The spinning apparatus is made up of two pairs of spinnerets located at the end of the ventral side of the opisthosoma. Both pairs of spinnerets are equipped with spigots (modified setae), i.e. external outlets of silk-producing glands which, in the case of posterior lateral spinnerets, are present on all three segments.The secreted silk, which hardens when exposed to air, is processed by movements of spinnerets and the opisthosoma. An investigation of spinning activity revealed two different manners in which silk is affixed to the ground: (1) by smearing silk secretion directly onto the surface of the substratum; or (2) by attaching silken fibers onto a layer of adhesive silk of attachment fields. The fibers connecting the walls of tubular shelters to the silk of attachment fields are essentially bundles of parallel nanofibrils. The connection between multifibrillar connecting fibers and the adhesive silk of attachment fields is, in essence, “silk-to-silk” connection. Nanoglobules (spherical subunits) are the basic microstructural blocks in the studied silk materials irrespective of whether the fibrils are a part of the tube, connecting fibers, or attachment fields. SEM images showed that the liquid silk, running through spigot ducts, has two components, which do not mix as they leave the spigots. The peripheral component of the solidified protein mixture surrounds the central component, which has a granular appearance

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 51
Author(s):  
Michela Relucenti ◽  
Giuseppe Familiari ◽  
Orlando Donfrancesco ◽  
Maurizio Taurino ◽  
Xiaobo Li ◽  
...  

Several imaging methodologies have been used in biofilm studies, contributing to deepening the knowledge on their structure. This review illustrates the most widely used microscopy techniques in biofilm investigations, focusing on traditional and innovative scanning electron microscopy techniques such as scanning electron microscopy (SEM), variable pressure SEM (VP-SEM), environmental SEM (ESEM), and the more recent ambiental SEM (ASEM), ending with the cutting edge Cryo-SEM and focused ion beam SEM (FIB SEM), highlighting the pros and cons of several methods with particular emphasis on conventional SEM and VP-SEM. As each technique has its own advantages and disadvantages, the choice of the most appropriate method must be done carefully, based on the specific aim of the study. The evaluation of the drug effects on biofilm requires imaging methods that show the most detailed ultrastructural features of the biofilm. In this kind of research, the use of scanning electron microscopy with customized protocols such as osmium tetroxide (OsO4), ruthenium red (RR), tannic acid (TA) staining, and ionic liquid (IL) treatment is unrivalled for its image quality, magnification, resolution, minimal sample loss, and actual sample structure preservation. The combined use of innovative SEM protocols and 3-D image analysis software will allow for quantitative data from SEM images to be extracted; in this way, data from images of samples that have undergone different antibiofilm treatments can be compared.


Author(s):  
Debbie G. Jones ◽  
Albert P. Pisano

A novel fabrication process is presented to create ultra thick ferromagnetic structures in silicon. The structures are fabricated by electroforming NiFe into silicon templates patterned with deep reactive ion etching (DRIE). Thin films are deposited into photoresist molds for characterization of an electroplating cell. Results show that electroplated films with a saturation magnetization above 1.6 tesla and compositions of approximately 50/50 NiFe can be obtained through agitation of the electrolyte. Scanning electron microscopy (SEM) images show that NiFe structures embedded in a 500 μm thick silicon wafer are realized and the roughening of the mold sidewalls during the DRIE aids in adhesion of the NiFe to the silicon.


2021 ◽  
Vol 21 (7) ◽  
pp. 3773-3778
Author(s):  
Keon-Young Kim ◽  
Se-Min Jeong ◽  
Chang-Yull Lee

This paper proposes a new mechanism for detecting microscopic damage of structures based on imitating the sensory organs of spiders. Therefore, it is essential to manufacture sensors that can react sensitively to the micro deformations of structures. Numerous cracks were intentionally generated to improve the sensitivity of the proposed sensor, and an increase in the gap of the crack was observed by scanning electron microscopy (SEM) observation. Electrohydrodynamic technology is used to detect deformations in a structure of depositing Ag nano paste on a polyethylene terephtha-late (PET) substrate. Ag nano lines are also observed by SEM images. The sensor is constructed as a grid structure, by forming layers patterned horizontally and vertically. An impact tester is used to verify the mechanism for structural health monitoring using the developed sensor. The resistance changes of the sensors are applied to estimate the structure’s damaged location. The intersections of the lines with varying resistance can be used to accurately detect crack initiation. The proposed mechanism is a powerful methodology for estimating and detecting microscopic deformations and damage to structures.


2020 ◽  
Vol 34 (24) ◽  
pp. 2050249
Author(s):  
L. Yoosefi ◽  
V. Setoodeh

High sensitivity and response ratio of magnetoimpedance (MI) sensors have raised interest for using them in different environments for detection of weak magnetic fields of magnetic elements even though the high dependence of the MI response to the surface condition of the MI sensor has limited its application in some environments. In this study, we investigate the effects originating from the MI measurement in moisturized air. Using scanning electron microscopy (SEM) images, it is observed that the surface of an Fe-based MI sensor has become rough and granular after the presence of moisture on its surface. Results can be useful for developing MI sensors for use in different environmental conditions.


2005 ◽  
Vol 53 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Soraya Naem

Scanning electron microscopy (SEM) was used to study the surface ultrastructure of female Thelazia lacrymalis obtained from naturally infected cattle. At the anterior end, the buccal capsule was cup shaped. The mouth was without lips and was surrounded by four cephalic papillae and two amphids. There were two lateral cervical papillae. Also, a single small papilla was seen on the ventral side, close to the vulvar opening. The vulva was located posterior to the end of the oesophagus and the tail carried an anal pore and a pair of phasmids near the tip. The cuticle was transversally annulated with fine striations.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1779 ◽  
Author(s):  
Christoph Naber ◽  
Florian Kleiner ◽  
Franz Becker ◽  
Long Nguyen-Tuan ◽  
Christiane Rößler ◽  
...  

A new method for the nuclear magnetic resonance (NMR) surface relaxivity calibration in hydrated cement samples is proposed. This method relies on a combined analysis of 28-d hydrated tricalcium silicate samples by scanning electron microscopy (SEM) image analysis and 1H-time-domain (TD)-NMR relaxometry. Pore surface and volume data for interhydrate pores are obtained from high resolution SEM images on surfaces obtained by argon broad ion beam sectioning. These data are combined with T2 relaxation times from 1H-TD-NMR to calculate the systems surface relaxivity according to the fast exchange model of relaxation. This new method is compared to an alternative method that employs sequential drying to calibrate the systems surface relaxivity.


Phytotaxa ◽  
2015 ◽  
Vol 236 (3) ◽  
pp. 257 ◽  
Author(s):  
Wei Zhang ◽  
Yan Ling Li ◽  
J Patrick Kociolek ◽  
Rui Lei Zhang ◽  
Li Qing Wang

During a survey of freshwater diatoms from streams in the west region of the Tianmu Mountains, Zhejiang Province, China, a new Oricymba species, Oricymba tianmuensis sp. nov. has been recorded. A detailed morphology description of O. tianmuensis is presented, based on light and scanning electron microscopy. Oricymba tianmuensis sp. nov. is characterized by a ridge along the valve face typical of the genus, as well as a linear-lanceolate, symmetrical or slightly dorsiventral outline with a gibbous central portion gradually tapering or nearly paralleling towards the bluntly cuneate poles, a distinct rhombic-lanceolate asymmetric central area with a distinct stigma on the ventral side of the central nodule, a slightly lateral raphe with widened proximal endings and strongly deflected distal endings, and weakly radiate striae. Morphological features of the taxon are compared with similar species, and the biogeography of the genus is summarized.


Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1536
Author(s):  
Ali Daraei ◽  
Marlien Pieters ◽  
Stephen R. Baker ◽  
Zelda de Lange-Loots ◽  
Aleksander Siniarski ◽  
...  

Scanning Electron Microscopy (SEM) is a powerful, high-resolution imaging technique widely used to analyze the structure of fibrin networks. Currently, structural features, such as fiber diameter, length, density, and porosity, are mostly analyzed manually, which is tedious and may introduce user bias. A reliable, automated structural image analysis method would mitigate these drawbacks. We evaluated the performance of DiameterJ (an ImageJ plug-in) for analyzing fibrin fiber diameter by comparing automated DiameterJ outputs with manual diameter measurements in four SEM data sets with different imaging parameters. We also investigated correlations between biophysical fibrin clot properties and diameter, and between clot permeability and DiameterJ-determined clot porosity. Several of the 24 DiameterJ algorithms returned diameter values that highly correlated with and closely matched the values of the manual measurements. However, optimal performance was dependent on the pixel size of the images—best results were obtained for images with a pixel size of 8–10 nm (13–16 pixels/fiber). Larger or smaller pixels resulted in an over- or underestimation of diameter values, respectively. The correlation between clot permeability and DiameterJ-determined clot porosity was modest, likely because it is difficult to establish the correct image depth of field in this analysis. In conclusion, several DiameterJ algorithms (M6, M5, T3) perform well for diameter determination from SEM images, given the appropriate imaging conditions (13–16 pixels/fiber). Determining fibrin clot porosity via DiameterJ is challenging.


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