Adhesive Substance Research Articles

Management systems of adhesive materials throughout the Neolithic in the North-West Mediterranean

Plant resins, tars and organic fossil substances provide valuable insights into the ecological, environmental and cultural contexts of ancient societies. Their study offers evidence of past know-how, production systems, socio-economic networks and mobility. In this paper, we present new data from 16 sites located in the North-West Mediterranean that provide new insights into the exploitation of these substances for their adhesive and hydrophobic properties throughout the Neolithic (6000-2500 cal BCE). The substances investigated are discussed in the light of their molecular composition, their uses and manufacturing processes. Spatial analyses were also performed to elucidate raw material procurement strategies.This study considerably increases the body of data available from the Mediterranean and tells a diachronic story of adhesive production and use throughout the Neolithic, highlighting the variability and complexity of production systems and supply networks at different spatial scales. While most adhesive and hydrophobic substances were probably collected locally, birch bark tar was very likely transported across long distances to reach Mediterranean coastal sites. Birch bark tar exploitation intensified in South-Eastern France during the Middle Neolithic, while the Late Neolithic is characterised by a diversification of the substances employed and their range of uses: bitumen, birch bark tar (pure or mixed with Pinaceae resin, beeswax and possibly fat/oil) were important materials that were used for a variety of purposes. Pure Pinaceae exudates were exclusively employed for waterproofing pottery. We also highlight the standardisation of birch bark tar production for adhesive manufacture observed in Provence during the first part of the 4th millennium cal. BCE.

Revisiting amino acid analyses for bioadhesives including a direct comparison of tick attachment cement (Dermacentor marginatus) and barnacle cement (Lepas anatifera)

With respect to potential applications in healthcare, pharmacy, the bonding industry, and cosmetics, biological adhesives produced from various animals are of high interest. A large number of species in the family Ixodidae produce an adhesive substance called attachment cement. This study focuses on the detailed investigation of the amino acid composition of the attachment cement from ticks (Dermacentor marginatus) and comparison with cement samples from barnacles (Lepas anatifera).Strong emphasis was laid on sample preparation of both types of cement and included the complete hydrolysis of proteins under either basic or acidic conditions. Stability of propyl chloroformate derivatives of the amino acids were measured by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) and gas chromatography electron ionisation tandem mass spectrometry (GC-EI-MS/MS) and were validated in terms of reproducibility and precision of analyses using NIST certified amino acid as well as protein standards. For the majority of the amino acids analytically valid recovery rates between 86 and 111% were achieved using GC-EI-MS/MS analysis after acidic hydrolysis.The method was applied for direct comparison of two biological glue systems, tick and barnacle cement. An outstandingly high content of glycine was present in the tick attachment cement; as were significant concentrations of leucine, serine and proline. In contrast, high levels of leucine, serine, aspartic acid/asparagine, glycine, glutamic acid/glutamine, alanine and valine were determined for barnacle cement. None of the samples showed the presence of 3,4-dihydroxy-phenylalanine (DOPA), yet tick attachment cement exhibited significantly higher concentration levels of tyrosine, the precursor of DOPA. It can clearly be stated that published results for amino acid analysis of barnacle cement show significantly under-/overestimation for some amino acids.Distinct differences in amino acid presence and concentration were observed for the two bio-adhesives. Although both have cement-like properties the data implied that different attachment mechanisms are involved for each of the organisms.

Hybrid Approaches for Selective Laser Sintering by Building on Dissimilar Materials.

We introduced a new approach in selective laser sintering for hybrid multicomponent systems by fabricating the sintered polyamide 12 (PA12) part directly onto a similar (PA12) or dissimilar (polyamide 6 (PA6) and tool steel 1.2709) joining partner. Thus, the need for adhesive substances or joining pressure was completely circumvented, leading to the possibility of pure hybrid lightweight bi-polymer or metal–polymer systems. By taking advantage of the heating capabilities of the sinter laser regarding the substrate surface, different exposure strategies circumvented the lack of overlapping melting temperatures of dissimilar polymers. Therefore, even sintering on non-PA12 polymers was made possible. Finally, the transfer on metallic substrates—made up by selective laser melting (SLM)—was successfully performed, closing the gap between two powder-based additive processes, selective laser sintering (SLS) and SLM.

Zinc antimonide thin film based flexible thermoelectric module

Zinc-antimonide is an encouraging alternative thermoelectric material to bismuth telluride based material for medium temperature range applications. In this work two fabrication concepts are proposed to build flexible modules using P-type zinc-antimony thin film and constantan straps, where the constantan was used as flexible electrical interconnect and N-type thermoelectric element. Nano-silver paste was applied as the bonding material and adhesive substance to tolerate a higher range of temperatures. The thin film specimen consisted of a 600 nm thin layer of zinc-antimonide deposited by magnetron co-sputtering on a 350 µm thick glass substrate. The proposed device configurations generate peak power of 3.5 μW and 13.5 μW at hot side temperatures of 250 °C and 330 °C, respectively.

Experimental study on cutting speed and surface roughness of pure copper in WEDM

Wire electrical discharge machining (WEDM) is an important way to manufacture copper electrode. In order to quickly manufacture copper electrode with good surface quality, the influence of electrical parameters on cutting speed and surface roughness of pure copper in wire electrical discharge machining was investigated. An analytical method was proposed to analyze the influence law from the aspects including discharge energy, the formation of adhesive substance on cutting surface and the discharge of electric erosion products. The results show that the pulse width has the greatest influence on the surface roughness and the peak current has the greatest influence on the cutting speed. Using the proposed analytical method, the influence relationship between the electrical parameters and the process objectives could be accurately analyzed, and then the actual production could be guided to select the appropriate electrical parameters according to the optimal process objectives pursued.

Further evidence for bow hunting and its implications more than 60 000 years ago: Results of a use-trace analysis of the bone point from Klasies River Main site, South Africa

The bone point (SAM 42160) from >60 ka deposits at Klasies River Main Site, South Africa, is reassessed. We clarify the stratigraphic integrity of SAM 42160 and confirm its Middle Stone Age provenience. We find evidence that indicates the point was hafted and partially coated in an adhesive substance. Internal fractures are consistent with stresses occasioned by high-velocity, longitudinal impact. SAM 42160, like its roughly contemporaneous counterpart, farther north at Sibudu Cave, likely functioned as a hafted arrowhead. We highlight a growing body of evidence for bow hunting at this early period and explore bow-and-arrow technology might imply about the cognition of people in the Middle Stone Age who were able to conceive, construct and use it.

USING SAGO PITH AS ADHESIVE SUBSTANCE IN VITRO DIGESTIBILITY OF COMPLETE RATION BISCUIT

The objective of the study was to determine in-vitro digestibility of complete ration biscuit using sago pith as adhesive substance. The experiment was arranged in Complete Randomized Design with 5 treatments and 5 replications. The treatments were P1 (50% mini elephant grass+ 20% leucaena + 30% sago pith + 0% rice bran), P2 (50% mini elephant grass+ 20% leucaena + 25% sago pith + 5% rice bran), P3 (50% mini elephant grass+ 20% leucaena + 20% sago pith +10% rice bran ) and P4 (50% mini elephant grass+ 20% leucaena + 15% sago pith + 15% rice bran). Variables measured were digestibility of dry (DM) and organic matter (OM), NH3 level, total volatile fatty acid (VFA), and rumen pH. The results show that the treatment has no significant effect on vitro digestibility of dry and organic matter. In vitro -digestibility is ranging from 90.7 – 91.4% and 87.5 – 88.4 % for DM and OM, respectively. In-vitro test on complete ration biscuit which consists of sago pith, rice bran, mini elephant grass and leucaena leucocephala has no significant (P>0.05) on NH3 level, total volatile fatty acid and rumen pH. In conclusion, sago pith can be potentially used as adhesive substance in formulating complete ration biscuit.

Plastics: physical-and-mechanical properties and biodegradable potential

Introduction. Processing agricultural waste into plant biodegradable plastics is a promising way for its recycling. This work featured the main physical-and-mechanical properties of plant plastics without adhesive substances obtained from millet husk and wheat husk and wood plastic obtained from sawdust, as well as their biodegradation potential.
 Study objects and methods. Objects of the study were plastics without adhesives based on wood sawdust, millet husk, and wheat husk.
 Results and discussion. We analyzed of the physical-and-mechanical parameters of the plant plastic based on millet husk, wheat husk, as well as wood plastic based on sawdust. The analysis showed that, in general, the strength characteristics of the wood plastics were higher than those of the plastics based on millet husk, especially flexural strength. Thus, the average value of the density of the wood plastic exceeded that of the plant plastic from millet husk by 10%, hardness by 40%, compression elasticity modulus by 50%, and flexural modulus by 3.9 times. It was found that wood and plant plastics obtained from sawdust, millet husk, and wheat husk without adhesives had a high biodegradation potential.
 Conclusion. The plastics obtained can be used as an insulating, building, and decorative material in the steppe regions experiencing a shortage of wood and wood powder.

Interfacial Colloidal Performance and Adhesive Strength of an Environmentally Friendly Cellulose-microcrystal-based Adhesive Substance

As one of the high-value and environmentally friendly chemical products, cellulose-based adhesive substance has been widely developed recently due to its extraordinary adhesion, interfacial flowability and high stability, along with low-impact side effects, outstanding degradability and biocompatibility. Also, microcrystalline-shaped cellulose has been fully exploited in functinalizing modification engineering. To eliminate the gap in application of cellulose-ether-based adhesion, we fabricated a new category of optimized cellulose sulfate product based on a system of analysis of key experimental factors: solvent pretreatment, degree of esterification, type and morphology of cellulose. Additionally, we focused on an all-round family of performance test of our product, containing characterization of structural and morphological features, test of water-based properties and inspection of adhesion behaviour. Within, the effect of adhesive strength in various solvents and under various conditions have been highlighted. The whole result shows a generally feasible synthetic approach and splendid performance as a novel green adhesive. The optimal design and synthesis of cellulose sulfate is verified to be eco-friendly, easy for optimization and greatly reproducible. Also, the product is shown to have tiptop viscosity, great adhesive strength, and colloidal potential like film forming due to the cross-linking network in the water-based environment. Finally, the product are demonstrated to be outstanding and widely applicable in mechanical strength. Specifically, it shows strong adhesion on different materials (metal, timber and glass) and tunability related to the kinds of additives. The addition of metallic salts and polymeric amine can evidently boost its adhesive strength. Overall, optimal analysis of cellulose sulfate adhesive on a microscale has forecasted great potential in low-carbon, fine-tunable, adhesive-related industry.

Briquettes manufacturing: mechanisation of briquette productions at SME santan coco

The fabrication of briquettes is required to be introduced extensively to society in order to provide additional economic value for charcoal crafters to increase their income. The SME Santan Coco as partnership enterprise of community service under supervising of Universitas Sumatera Utara has been producing briquettes since 2018 resulted from waste of coconut milk production. However, the methodology of producing briquettes can be considered to be insufficient. The production is started by the addition of charcoal powder with adhesives compounds which is followed manual stirring. The moulding process involves by using a lever utilizing body-weight, which produces two briquettes. The charcoal powder is obtained by manually crushing the charcoal, so that its granular size is not uniform. The briquette production is very slow due to the equipment used produces two briquettes. On the other hand, the preparation of raw materials into the moulding equipment requires longer time, as well as removing the ready-to-use briquette from the mould. The prepared mixture must be printed immediately, so that the adhesive is not dried. The final product fabricated by the partner shows that the granular sizes are different which affects the density parameters, productions volume accounted for 50 kg per day. Therefore, a mechanism of briquette production is proposed and introduced to the partner, which involves from charcoal breaking, mixing and molding briquettes. A charcoal crusher uses a hammer mill system with 12 eyes, equipped with a filter. The mixing of adhesive substances utilizes a ribbon blade mixing system, while the briquette printing is designed with a screw system. After being implemented, a very significant increase in production up to 500 kg of wet briquettes per day with higher density and more uniform as well as neater granular size has been obtained.

Boston Ivy Disk-Inspired Pressure-Mediated Adhesive Film Patches.

Boston ivy (Parthenocissus tricuspidata) climbs brick walls using its tendril disks, which excrete a sticky substance to perform binding and attachment. While the cellular structures and adhesive substances involved have been identified for decades, their practical applicability as an adhesive has not yet been demonstrated. A Boston ivy disk-inspired adhesive film patch system is reported in which structural and compositional features of the Boston ivy disk are mimicked with a form of thin adhesive film patches. In analogy to the sticky disk of a mature ivy in which porous microchannels are occupied by catechol-containing microgranules on the bound site, 3,4-dihydroxylphenylalanine bolaamphiphile nanoparticle (DOPA-C7 NP)-coated alginate microgels are two-dimensionally positioned into the cylindrical holes that are periodically micropatterned on the flexible stencil film. Finally, it is demonstrated that the pressurization of the patch breaks the microgels filled in the holes, releasing the polysaccharides and leading to crosslinking with DOPA-C7 NPs via ligandation with combined Ca2+ and Fe3+ ions, thus enabling development of a pressure-mediated adhesion technology.

Assessment of Stickiness with Pressure Distribution Sensor Using Offset Magnetic Force.

The quantification of stickiness experienced upon touching a sticky or adhesive substance has attracted intense research attention, particularly for application to haptics, virtual reality, and human–computer interactions. Here, we develop and evaluate a device that quantifies the feeling of stickiness experienced upon touching an adhesive substance. Keeping in mind that a typical pressure distribution sensor can only measure a pressing force, but not a tensile force, in our setup, we apply an offset pressure to a pressure distribution sensor and measure the tensile force generated by an adhesive substance as the difference from the offset pressure. We propose a method of using a magnetic force to generate the offset pressure and develop a measuring device using a magnet that attracts magnetic pin arrays and pin magnets; the feasibility of the method is verified with a first prototype. We develop a second prototype that overcomes the noise problems of the first, arising from the misalignment of the pins owing to the bending of the magnetic force lines at the sensor edges. We also obtain measurement results for actual samples and standard viscosity liquids. Our findings indicate the feasibility of our setup as a suitable device for measuring stickiness.

External Morphology and Ultrastructure of Tegumental Glands of Aegla platensis (Crustacea, Anomura, Aeglidae) Pleopods: Might They Play A Role in Egg Attachment?

Egg incubation on the female abdomen is the parental care behavior observed in aeglids, in which eggs are kept adhered to maternal pleopods and maintained, cleaned and aerated. In A. platensis, egg attachment occurs with the aid of pleopodal setae, which are twisted around their axis in the distal region, forming the funiculus, and pleopodal glands, which are responsible for the production of the adhesive substance that seems to be involved in egg fixation to pleopodal setae. Those glands are acini formed by secretory cells arranged concentrically around a central duct, giving them a rosette appearance. Two types of secretory cells were observed, those that produce electron-lucid vesicles and those having electron-dense ones. Both kinds of vesicles are released in a duct whose opening pore is located on the pleopodal surface and constitute the adhesive substance that coats eggs and pleopodal setae, ensuring egg fixation to the female body and maternal care maintenance. This study investigates the internal and external morphology of Aegla platensis pleopods, to understand the egg attachment process and identify the structures involved in this phenomenon. Three microscopy techniques are used: scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy (OM).

The Transcriptome of the Salivary Glands of Amblyomma aureolatum Reveals the Antimicrobial Peptide Microplusin as an Important Factor for the Tick Protection Against Rickettsia rickettsii Infection.

The salivary glands (SG) of ixodid ticks play a pivotal role in blood feeding, producing both the cement and the saliva. The cement is an adhesive substance that helps the attachment of the tick to the host skin, while the saliva contains a rich mixture of antihemostatic, anti-inflammatory, and immunomodulatory substances that allow ticks to properly acquire the blood meal. The tick saliva is also a vehicle used by several pathogens to be transmitted to the vertebrate host, including various bacterial species from the genus Rickettsia. Rickettsia rickettsii is a tick-borne obligate intracellular bacterium that causes the severe Rocky Mountain spotted fever. In Brazil, the dog yellow tick Amblyomma aureolatum is a vector of R. rickettsii. In the current study, the effects of an experimental infection with R. rickettsii on the global gene expression profile of A. aureolatum SG was determined by next-generation RNA sequencing. A total of 260 coding sequences (CDSs) were modulated by infection, among which 161 were upregulated and 99 were downregulated. Regarding CDSs in the immunity category, we highlight one sequence encoding one microplusin-like antimicrobial peptide (AMP) (Ambaur-69859). AMPs are important effectors of the arthropod immune system, which lack the adaptive response of the immune system of vertebrates. The expression of microplusin was confirmed to be significantly upregulated in the SG as well as in the midgut (MG) of infected A. aureolatum by a quantitative polymerase chain reaction preceded by reverse transcription. The knockdown of the microplusin expression by RNA interference caused a significant increase in the prevalence of infected ticks in relation to the control. In addition, a higher rickettsial load of one order of magnitude was recorded in both the MG and SG of ticks that received microplusin-specific dsRNA. No effect of microplusin knockdown was observed on the R. rickettsii transmission to rabbits. Moreover, no significant differences in tick engorgement and oviposition were recorded in ticks that received dsMicroplusin, demonstrating that microplusin knockdown has no effect on tick fitness. Further studies must be performed to determine the mechanism of action of this AMP against R. rickettsii.

Organotypic Culture of Neonatal Murine Inner Ear Explants.

The inner ear is a complex organ containing highly specialised cell types and structures that are critical for sensing sound and movement. In vivo, the inner ear is difficult to study due to the osseous nature of the otic capsule and its encapsulation within an intricate bony labyrinth. As such, mammalian inner ear explants are an invaluable tool for the study and manipulation of the complex intercellular connections, structures, and cell types within this specialised organ. The greatest strength of this technique is that the complete organ of Corti, or peripheral vestibular organs including hair cells, supporting cells and accompanying neurons, is maintained in its in situ form. The greatest weakness of in vitro hair cell preparations is the short time frame in which the explanted tissue remains viable. Yet, cochlear explants have proven to be an excellent experimental model for understanding the fundamental aspects of auditory biology, substantiated by their use for over 40 years. In this protocol, we present a modernised inner ear explant technique that employs organotypic cell culture inserts and serum free media. This approach decreases the likelihood of explant damage by eliminating the need for adhesive substances. Serum free media also restricts excessive cellular outgrowth and inter-experimental variability, both of which are side effects of exogenous serum addition to cell cultures. The protocol described can be applied to culture both cochlear and vestibular explants from various mammals. Example outcomes are demonstrated by immunohistochemistry, hair cell quantification, and electrophysiological recordings to validate the versatility and viability of the protocol.

Functions and mechanisms: polygalacturonases from plant pathogenic fungi as pathogenicity and virulence factors

Polygalacturonases (PGs) are widely distributed pectic enzymes in microorganisms that are plant pathogens, and those that are not plant pathogens, and in plants themselves. PGs degrade the adhesive pectic substances of the middle lamella and cell wall, contributing to fungal penetration, plant tissue collapse and nutrient acquisition. Not all PGs that are produced by plant pathogens are required for pathogenicity or virulence, and PGs are present in nonpathogens. This review provides an overview of the functions and mechanisms of PGs in the pathogenicity and virulence of fungi and interpretations of the keys to PG involvement in pathogenesis.

Robust, Transparent, and Superhydrophobic Coating Fabricated with Waterborne Polyurethane and Inorganic Nanoparticle Composites

We report the fabrication of a robust, transparent, and superhydrophobic organic–inorganic composite coating with simple, low-cost, effective, and environmentally friendly characteristics. First, a waterborne polyurethane (WPU) emulsion and silica fluoride (F-SiO2) nanoparticle dispersion were synthesized. Subsequently, the organic–inorganic superhydrophobic surfaces with low surface energy were constructed by spraying, in order, the WPU emulsion and F-SiO2 nanoparticle dispersion on substrates. The robust composite coating had superhydrophobicity and good optical transparency, in which the WPU provided a strongly adhesive elastic substance for the anchoring of superhydrophobic F-SiO2 nanoparticles to further construct a mechanically and chemically resilient nanocomposite coating. After 250 cycles of abrasion, a long period of ultraviolet irradiation, and oil-pollution and cross-cut tests, the nanocomposite coating still exhibited excellent properties including good self-cleaning, transparency, abrasion r...

The use of cyclohexane as new solvent for airborne pollen sampling

Almost all the aerobiological networks used the non-volatile silicone fluid as a capture medium adhesive on the Melinex tape of Hirst-type volumetric samplers. This adhesive was prepared with carbon tetrachloride, considered as a carcinogenic agent. Since that, there is a spreading interest to find an alternative solvent for continuing the aerobiological sampling. In this study, we examined the impaction efficiency of the cyclohexane and carbon tetrachloride solvent, widely used in aerobiological studies. The results revealed that there is no significant difference between the two solvents and that cyclohexane can be used as a new solvent of the adhesive substance for airborne pollen sampling.

The tadpole of Afrixalus knysnae (Loveridge) (Anura: Hyperoliidae), with comments on reproductive biology.

Leaf-folding frogs of the genus Afrixalus comprise 33 species across South-East, Central and West Africa (Frost 2018) with tadpoles being described for Afrixalus aureus Pickersgill, A. delicatus Pickersgill, A. dorsalis (Peters), A. fornassinii (Bianconi), A. fulvovittatus (Cope), A. laevis (Ahl), A. morerei Dubois, A. nigeriensis Schiøtz, A. spinifrons (Cope), A. stuhlmanni (Pfeffer), A. uluguruensis (Barbour Loveridge), A. vibekensis Schiøtz, A. vittiger Peters, and A. weidholzi (Mertens) (see Pickersgill 2005; Channing et al. 2012). Members of the genus have a unique approach to egg deposition, laying their eggs on soft-leaved hydrophytes. The male folds or rolls the leaf with his hind legs into a sheath following oviposition and fertilisation (Rose 1950; Wager 1954; Du Preez Carruthers 2017), excreting an adhesive substance and enclosing the eggs within while the "glue" cures (Rose 1950, Wager 1954, authors pers. obs.).

Measurement of legacy and emerging flame retardants in indoor dust from a rural village (Kopawa) in Nepal: Implication for source apportionment and health risk assessment

Under the Stockholm Convention, signatory countries are obliged to direct source inventories, find current sources, and provide ecological monitoring evidence to guarantee that the encompassing levels of persistent organic pollutants (POPs) are declining. However, such monitoring of different types of POPs are to a great degree constrained in most developing countries including Nepal and are primarily confined to suspected source area/ densely populated regions. In this study, 9 polybrominated diphenyl ethers (PBDEs), 2 dechlorane plus (DPs), 6 novel brominated flame retardants (NBFRs) and 8 organophosphate ester flame retardants (OPFRs) were investigated in indoor dust from a rural area (Kopawa) in Nepal in order to evaluate their occurrence/level, profile, spatial distribution and their sources. Additionally, health risk exposure was estimated to anticipate the possible health risk to the local population. The results showed that OPFRs was the most abundant FR measured in the dust. The concentration of ∑8OPFRs was about 2, 3 and 4 orders of magnitude higher than the ∑6NBFRs, ∑9PBDEs, and ∑2DPs, respectively. Tris (methylphenyl) phosphate (TMPP) and Tris (2-ethylhexyl) phosphate (TEHP) were the most abundant OPFRs analyzed in the dust; while decabromodiphenyl ethane (DBDPE) exceeded among NBFRs. Likewise, 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenylether (BDE-209) was the most identified chemical among PBDEs. The total organic carbon (TOC) content in dust was significantly and positively connected with octa-BDEs (Rho = 0.615, p < 0.01), BTBPE (Rho = 0.733, p < 0.01), TPHP (Rho = 0.621, p < 0.01), TEHP (Rho = 0.560, p < 0.01) and TMPPs (Rho = 0.550, p < 0.01), while black carbon (BC) was either weakly related or not related, suggesting little or no impact of BC in the distribution of FRs. Principal component analysis indicated the contribution from commercial penta-, octa- and deca-BDEs formulation, the adhesive substance, food packaging and paints, and degradation of BDE-209 as the essential sources of FRs. Health risk exposure estimates showed that dermal absorption via dust as the primary route of FRs intake. The estimated daily exposure of PBDEs, NBFRs and OPFRs were 2–10 orders of magnitude lower than their corresponding reference dose (RfD), suggesting insignificant risk. However, other routes such as inhalation and dietary intake might still be significant in the case of Kopawa which should be tested in future.