Water-soluble Glue Research Articles

Fine structural aspects on the web glue production in the golden orb-web spider Trichonephila clavata

ABSTRACT The water-soluble glue substance of the capture threads in Trichonephila clavata is solely produced from two pairs of aggregate silk glands. During the web glue production, secretory vesicles were synthesized via the extensive rough endoplasmic reticulum of epithelial cells. Unlike the clearly described fibrous web production in spiders, the process of aqueous web glue production appears to involve either a condensing or a packaging step by the Golgi complex. In particular, the fine structure of secretory vesicles varies from cell to cell and may represent the secretory cycle. The electron-dense multivesicular bodies were clearly visible as discrete droplets, and the mature secretory product in the glandular epithelium appeared as a spherical vacuole grown by fusion with surrounding small vesicles. Our fine structural observation reveals that the secretion occurs when the release of secreted material involves the loss of part of the cytoplasm. The bleb along the luminal surface of the secretory cells and membrane-bound extracellular vesicles which pinched off from the cell suggests that the secretory product is released by the mechanism of apocrine secretion.

Convergent Evolution of Adhesive Properties in Leaf Insect Eggs and Plant Seeds: Cross-Kingdom Bioinspiration.

Plants and animals are often used as a source for inspiration in biomimetic engineering. However, stronger engagement of biologists is often required in the field of biomimetics. The actual strength of using biological systems as a source of inspiration for human problem solving does not lie in a perfect copy of a single system but in the extraction of core principles from similarly functioning systems that have convergently solved the same problem in their evolution. Adhesive systems are an example of such convergent traits that independently evolved in different organisms. We herein compare two analogous adhesive systems, one from plants seeds and one from insect eggs, to test their properties and functional principles for differences and similarities in order to evaluate the input that can be potentially used for biomimetics. Although strikingly similar, the eggs of the leaf insect Phyllium philippinicum and the seeds of the ivy gourd Coccinia grandis make use of different surface structures for the generation of adhesion. Both employ a water-soluble glue that is spread on the surface via reinforcing fibrous surface structures, but the morphology of these structures is different. In addition to microscopic analysis of the two adhesive systems, we mechanically measured the actual adhesion generated by both systems to quantitatively compare their functional differences on various standardized substrates. We found that seeds can generate much stronger adhesion in some cases but overall provided less reliable adherence in comparison to eggs. Furthermore, eggs performed better regarding repetitive attachment. The similarities of these systems, and their differences resulting from their different purposes and different structural/chemical features, can be informative for engineers working on technical adhesive systems.

Clinical and microbiological aspects of the auricle prosthetic reconstruction

Relevance. Plastic and reconstructive surgery of the missing outer ear is not always successful and may cause complications. Prosthetic reconstruction using silicone ectoprostheses (epitheses) is an alternative solution to this problem. Purpose – the study aimed to verify clinical and microbiological protocol of prosthetic rehabilitation of patients with a missing auricle using temporary silicone epitheses during implant osseointegration placed for the final magnet-bar retention system and assessment of the prosthetic reconstruction effe ctiveness.Materials and methods. The study compared and analyzed the quality of life and microbial colonization of the skin biotope in the main group patients – with temporary silicone auricle epithesis during extraoral implant osseointegration and in the control group without such prostheses. Quality of life was assessed before and after treatment using the automated questionnaires (WHOQOL-BREF and QL PAER) developed by us for mobile devices. We determined the quantitative and qualitative composition of the skin microbiota behind the ear in all patients with fixed silicone samples for seven days.Results. According to all domains of the "WHOQOL-BREF" and "QL PAER" questionnaires, an integral index of QLI (p < 0.05) was reliably higher after prosthesis fixation in the main group. Skin biotope colonization by strains of resident microorganisms in the region of Technovent silicone epithesis increased if B-460 glue was applied, and the water-soluble G609 glue did not have a similar effect.Conclusion. A digital protocol for the manufacture of a temporary silicone epithesis of the auricle for the period of extraoral implant osseointegration, with the fixation on a water-soluble glue, improves the quality of life of patients with anotia and minimizes microbial colonization of the biotope of t he skin behind the ear.

Influence of Polyvinyl Alcohol Powder on the Mechanical Performance and Volume Stability of Sulfoaluminate–Portland Cement Composite

Cement quick repair materials generally have the defects of brittleness and early shrinkage. The modification of composite cement mortar by water-soluble glue powder—polyvinyl alcohol (PVA)—was studied in the condition of settled water cement ratio. At 90 days, the maximum flexural strength of mortar was 15.4 MPa, which was 1.3 times of the group without PVA and there was no strength shrinkage phenomenon. Through the analysis of the porosity, PVA improved the total porosity; high porosity could play a better role of buffering and absorbing the impact stress, effectively improving the toughness of mortar. At 28 days, the maximum impact resistance was 1.72 J/cm2, which was 1.75 times of the group without PVA. In addition, the increased total porosity also greatly absorbed the shrinkage stress at the early stage, and reduced the mortar self-shrinkage. When the PVA content was 1%, the volume self-shrinkage of mortar decreased from the initial 3360 μm·m−1 to 700 μm·m−1. According to the analysis of hydration heat, the addition of PVA effectively reduced the early hydration heat release rate and alleviated the concentrated heat release phenomenon to a certain extent. In this paper, the hydration reaction of composite cement and the action mechanism of PVA in composite cement were studied by means of X-ray diffraction, infrared spectrum and hydration heat analysis.

Not all spider silks are antimicrobial

Spider silks are thought to have antimicrobial properties that prevent rapid degradation. Despite its biomedical potential, little research has focused on antimicrobial properties of spider silks. We tested the antimicrobial properties of gluey gumfoot capture threads of the western black widow spider, Latrodectus hesperus Chamberlin & Ivie, 1935, both for whole threads and after separating viscid silk from water soluble glue components using a water wash. Capture threads, unlike dry dragline silk, have a glue coating that may promote different interactions of bacteria with the material. Antimicrobial activity was assessed in an aqueous Escherichia coli cell culture and growth of colonies was counted over 24 hours. In contrast with previous research, mostly on dry dragline silk, we found an increase in bacterial growth for whole gumfoot thread treatment, but no effect of the solid and water-soluble components individually. These results suggest that better and proper procedures are needed for testing antimicrobials in silks, with controlled experiments using just one type of silk.

Static Edgewise Crush Property and Mechanical Model of Apposition Combined C-Flute Corrugated Paperboard

C-flute corrugated paperboards with length of 100mm were combined side by side with/without water soluble glue to study the static edgewise crush property. Combinations with different height (20, 25, 40, 60, 80, and 100mm), different number of layers, with or without glue were tested to obtain mechanical property and buffering property data of C-flute corrugated paperboard. The result indicates that the deformation of paperboard combinations can be divided into three stages as elastic-like deform stage, yield-like stage and high plastic deformation stage. The mechanical model of the elastic-like deform stage was built according to numerical fitting, which shows that the relationship between the stress and the quadratic function of strain is exponential.

A Robotic System for High-Throughput-Rate Target Assembly

A system for automated assembly and mounting of targets at high throughput rates has been developed at General Atomics. Major components of the system include two, six-axis industrial robot arms; a high-precision glue-dispensing system; a vision system; and a piezoelectric translation stage for precise positioning of parts. All operations are controlled by computer, with feedback from the vision system to the piezoelectric stage and robots.Assembly and mounting of cone-in-shell targets is described. A key requirement for these targets is that the virtual cone tip (the projection of the cone sides to a single point in space) must be aligned to the shell center to within ±10 μm. Major steps in the process include (a) gluing capsules to zirconia handling posts with water-soluble glue; (b) cutting holes in the tops of the capsules to accept cones; (c) assembling the cones to the capsules, forming a target; (d) gluing carbon fiber “stalks” to carriers on which the targets are mounted; and (e) removing targets from the handling posts and gluing them to stalks on carriers.The system has been demonstrated to be capable of assembling and mounting on the order of 500 targets per week. With further optimization, throughput rates of 1000 per week appear achievable.

Isolation, purification and characterization of silk protein sericin from cocoon peduncles of tropical tasar silkworm, Antheraea mylitta

A high molecular weight water-soluble glue protein, sericin was identified in the cocoon peduncle (a strong thread connecting the cocoons to the branches of the tree with a ring) of the tropical tasar silkworm, Antheraea mylitta. The sericin was isolated by 8 M urea containing 1% sodium dodecyl sulfate and β-mercaptoethenol (2%) or by 1% sodium chloride. The protein was purified by gel filtration chromatography. In SDS-PAGE, a single band of approximately 200 kDa was detected both in non-reducing and reducing conditions. Amino acid analysis showed that the protein is enriched in glycine and serine. There is a slight difference observed in amino acid composition between the sericin from cocoon peduncle and cocoon of A. mylitta. Secondary structure estimation by circular dichroism spectrometry showed 36.7% β-sheets, 52.7% random coils, 10.6% turns and no helices.

Bond strengths and remnant adhesive resin on debonding for orthodontic bonding techniques

Bond strengths and remnant adhesive resin on the tooth surface after debonding for three bonding techniques used to attach foil mesh orthodontic brackets to 315 freshly extracted bovine incisor teeth were compared in an in vitro study. Each method of bonding used 105 teeth in groups of 15, bonded with seven different (bis-GMA type) two-paste chemically cured resins. The direct method comprised bonding the attachments directly to the incisors with the composite resin. The indirect-1 method comprised securing attachments to die-stone models of the teeth with a water soluble glue, making silicone positioners to transfer the brackets from the models to the teeth, and bonding to the teeth with the use of the two-paste composite resin system. The indirect-2 method comprised bonding the attachments to die-stone models of the teeth with composite resin, making silicone positioners to transfer the brackets from the models to the teeth, and bonding to the teeth with the use of unfilled sealant resin. Significant differences in bond strength existed among the groups evaluated. The direct technique had statistically significant ( p < 0.05) higher bond strength as compared with the indirect-1 and indirect-2 techniques in four of the seven groups evaluated. The indirect-1 and indirect-2 techniques were not significantly different ( p < 0.05) in bond strength in six of seven groups tested. The indirect-2 technique had significantly lower adhesive remnant index scores (ARI) compared with the direct and indirect-1 techniques. The direct technique had significantly lower adhesive remnant indices compared with the indirect-1 technique. Thus the indirect-2 technique of bonding orthodontic brackets to teeth demonstrated comparable laboratory bond strengths and easier clean-up during the debonding procedure. (A M J O RTHOD D ENTOFAC O RTHOP 1995;108:302-7.)

Comparison of Slump Cone and V-B Tests as Measures of Workability for Fiber-Reinforced and Plain Concrete

Abstract In this paper, two popular measures of workability, namely, slump and V-B time, are compared for plain and steel (hooked) fiber-reinforced concrete. The results are based on experiments made on both types of concrete with and without high-range, water-reducing admixture. The fibers were 50 mm (2 in.) long with deformed ends glued together side by side into bundles (collated) with a water-soluble glue. The W-C ratio varied from 0.3 to 0.62. The air content ranged from 2 to 12%. In terms of workability, the whole spectrum ranging from no slump concrete to flowing concrete was covered. Based on the results of this investigation, the following general equation can be written relating V-B time and slump log10(V∙B)=a−b(slump) The addition of high-range water reducer and fibers influences the relationship and hence the constants a and b. The slope of the line, b, is highest for plain concrete without high-range, water-reducing admixture and lowest for fiber-reinforced concrete. In the case of plain concrete, the addition of high-range water reducer seems to result in a more cohesive mixture. As a result, V-B times can be recorded for slumps as high as 163 mm (6.4 in.). Without the addition of the admixture, concrete seems to collapse around a slump of 89 mm (3.5 in.). The addition of fibers increases the cohesiveness of the mixture considerably. For fiber-reinforced concrete made using high-range water reducer, V-B time could be measured for slumps as high as 221 mm (8.7 in.). Generally for a given slump, fiber-reinforced concrete has a higher V-B time than plain concretes.

A new method for detecting histamine release.

Glass microfibres have been found to bind histamine with high affinity and selectivity. A new test for measuring basophil histamine release has been developed using the glass microfibres as a solid phase. Glass microfibres are crushed and fixed to the bottom of microtitre plates with a water-soluble glue. Histamine release is performed in the glass microfibre -prepared microtitre plates by challenging 100 microliter washed blood with 20 microliter antigen per well for 90 min at 37 degrees C. Released histamine is bound with high affinity to the glass microfibres , since 90% of histamine in the solution is adsorbed to the fibres. After incubation the microtitre plate is washed with H2O to remove cells and interfering substances. Fibre-bound histamine is detected by the fluorometric o-phthaldialdehyde method. The sensitivity of the assay is 0.63 ng histamine, 2 HCl and the histamine standard curve is linear up to at least 5 ng histamine, 2 HCl. Optimal conditions for the new assay are described. After challenge with anti-Ige a comparison with the conventional histamine release from Ficoll-Hypaque-isolated leukocytes showed almost identical results.

Deterrence of repeated oviposition in sorghum shootflyAtherigona soccata

The sorghum shootfly,Atherigona soccata, under low population density conditions lays one egg per sorghum plant. Possible regulatory mechanisms of this oviposition behavior are reported. The presence of an egg thoroughly washed and reattached to a leaf does not deter further oviposition, indicating the absence of visual cues. When washings from eggs were sprayed on sorghum plants, or when plants from which eggs had been removed were presented to a gravid female, significant deterrence was observed. Apparently a deterrent pheromone is associated with the water-soluble glue with which the females attach their eggs to the leaves. Some deterrent effect persists for at least 7 days.