•The thicker the CLT panel is, the lower its bending and rolling shear strength.•Rolling shear strength values for Sitka spruce of 1.0–2.0N/mm2.•‘Global’ deformation results closely match theoretical ...stiffness.•Cross-lamination provides no strengthening effect for in-plane bending behaviour.
An investigation was carried out on CLT panels made from Sitka spruce in order to establish the effect of the thickness of CLT panels on the bending stiffness and strength and the rolling shear. Bending and shear tests on 3-layer and 5-layer panels were performed with loading in the out-of-plane and in-plane directions. ‘Global’ stiffness measurements were found to correlate well with theoretical values. Based on the results, there was a general tendency that both the bending strength and rolling shear decreased with panel thickness. Mean values for rolling shear ranged from 1.0N/mm2 to 2.0N/mm2.
AbstractTests were conducted of the bonding shear strength of different bamboo configurations in terms of grain direction, adhesive, and clamping pressure. The bonding shear tests were carried out ...with two basic configurations: glued together with the grain in the same direction, and cross-laminated. Five different adhesives were used: emulsion polymer isocyanate (EPI), polyurethane (PUR), melamine-urea-formaldehyde (MUF), hybrid polymer adhesive (HPA), and polyvinyl acetate (PVA). To assess the optimum value, specimens were prepared with three clamping pressures. According to the test results, the most suitable adhesive for glued laminated bamboo surface is MUF; EPI is not effective for bonding laminated bamboo elements, and PVA performs the best for scrimber produced with cross-laminated bamboo. The results also showed that end grain specimens had the highest bonding shear strengths among the four configurations, and that, in accordance with the properties of raw bamboo, cross-laminated types exhibited similar mechanical characteristics in both directions. It can be concluded that the testing method used for cross laminated timber is also suitable for assessing the shear strength of adhesive bonds for cross-laminated bamboo.
•Majority of pores created by SAP are ‘ink-bottle’ and/or closed.•SAPs increase ‘polymer pore’ walls’ strengths by densification of microstructure.•The addition of SAP with high WAC results in an ...increased compressive strength.•SAPs increase number of small pores which do not affect compressive strength.
The paper is focused on microstructure and strength development in fly ash cementitious mortars containing superabsorbent polymers. In order to evaluate the effect of different water absorption/desorption kinetics of SAPs, comprehensive MIP and SEM analysis supplemented by the mechanical properties assessments have been performed. The vast majority of pores created by SAP are ‘ink-bottle’ and/or closed. Gradual release of water stored by SAP facilitates formation of denser, more homogenous and predictable cementitious matrix, further enhanced by the pozzolanic reaction of fly ash with portlandite. Addition of SAP with high water absorption capacity results in an increased compressive strength.
Antimicrobial peptides emerge as compounds that can alleviate the global health hazard of antimicrobial resistance, prompting a need for novel computational approaches to peptide generation. Here, we ...propose HydrAMP, a conditional variational autoencoder that learns lower-dimensional, continuous representation of peptides and captures their antimicrobial properties. The model disentangles the learnt representation of a peptide from its antimicrobial conditions and leverages parameter-controlled creativity. HydrAMP is the first model that is directly optimized for diverse tasks, including unconstrained and analogue generation and outperforms other approaches in these tasks. An additional preselection procedure based on ranking of generated peptides and molecular dynamics simulations increases experimental validation rate. Wet-lab experiments on five bacterial strains confirm high activity of nine peptides generated as analogues of clinically relevant prototypes, as well as six analogues of an inactive peptide. HydrAMP enables generation of diverse and potent peptides, making a step towards resolving the antimicrobial resistance crisis.
Contemporary medicine has been confronted by multidrug resistance. Therefore, new antibiotics are sought to alleviate the problem. In this study, we estimated the effect of the positioning and extent ...of lipidation (mainly octanoic acid residue) in the KR12-NH
molecule on antibacterial and hemolytic activities. The effect of the conjugation of benzoic acid derivatives (C
H
-X-COOH, where X: CH
, CH
-CH
, CH=CH, C≡C, and CH
-CH
-CH
) with the
-terminal part of KR12-NH
on biological activity was also studied. All analogs were tested against planktonic cells of ESKAPE bacteria and reference strains of
. The effect of lipidation site on the helicity of the KR12-NH
analogs was studied using CD spectroscopy. The ability of the selected peptides to induce the aggregation of POPG liposomes was evaluated with DLS measurements. We demonstrated that both the site and extent of peptide lipidation play an essential role in the bacterial specificity of the lipopeptides. Most of the C
-KR12-NH
(
) analogs that were more hydrophobic than the parent compound were also more hemolytic. A similar relationship was also found between the α-helical structure content in POPC and hemolytic activity. It is worth emphasizing that in our study, the highest selectivity against
strains with an SI value of at least 21.11 exhibited peptide
obtained by the conjugation of the octanoic acid with the
-terminus of retro-KR12-NH
. All lipidated analogs with the highest net charge (+5) were the most selective toward pathogens. Therefore, the overall charge of KR12-NH
analogs plays pivotal role in their biological activity.
This paper addresses the quality of the interface- and edge-bonded joints in layers of cross-laminated timber (CLT) panels. The shear performance was studied to assess the suitability of two ...different adhesives, polyurethane (PUR) and phenol-resorcinol-formaldehyde (PRF), and to determine the optimum clamping pressure. Since there is no established testing procedure to determine the shear strength of the surface bonds between layers in a CLT panel, block shear tests of specimens in two different configurations were carried out, and further shear tests of edge-bonded specimen in two configurations were performed. Delamination tests were performed on samples which were subjected to accelerated aging to assess the durability of bonds in severe environmental conditions. Both tested adhesives produced boards with shear strength values within the edge-bonding requirements of prEN 16351 for all manufacturing pressures. While the PUR specimens had higher shear strength values, the PRF specimens demonstrated superior durability characteristics in the delamination tests. It seems that the test protocol introduced in this study for crosslam-bonded specimens, cut from a CLT panel, and placed in the shearing tool horizontally, accurately reflects the shearing strength of glue lines in CLT.
A series of quaternary diammonium salts derivatives of 1,4:3,6-dianhydro-l-iditol were synthesized, using isommanide (1,4:3,6-dianhydro-d-mannitol) as a starting material. Both aromatic (pyridine, ...4-(
,
-dimethylamino)pyridine (DMAP), (3-carboxamide)pyridine;
-methylimidazole) and aliphatic (trimethylamine,
,
-dimethylhexylamine,
,
-dimethyloctylamine,
,
-dimethyldecylamine) amines were used, giving eight gemini quaternary ammonium salts (QAS). All salts were tested for their antimicrobial activity against yeasts,
and
, as well as bacterial
and
reference strains. Moreover, antibacterial activity against 20 isolates of
collected from patients with skin and soft tissue infections (
= 8) and strains derived from subclinical bovine mastitis milk samples (
= 12) were evaluated. Two QAS with octyl and decyl residues exhibited antimicrobial activity, whereas those with two decyl residues proved to be the most active against the tested pathogens, with MIC of 16-32, 32, and 8 µg/mL for yeast,
and
reference and clinical strains, respectively. Only QAS with decyl residues proved to be cytotoxic in MTT assay against human keratinocytes (HaCaT), IC
12.8 ± 1.2 μg/mL. Ames test was used to assess the mutagenic potential of QAS, and none of them showed mutagenic activity in the concentration range 4-2000 µg/plate.
In multi-criteria decision-making (MCDM) problems the decision-maker is often forced to accept a not ideal solution. If the ideal choice exists, it would be certainly chosen. The acceptance of a non- ...ideal solution leads to some inadequate properties in the chosen solution. MCDM methods help the decision-maker to structure his needs considering different units, in which the properties of the solutions are expressed. Secondly, with MCDM tools the assessment of the available solutions can be calculated with consideration of the decision-maker’s needs. The incorporation of the cost criterion into the decision maker’s preferences calculation, and the solution assessment calculation, deprives the decision-maker of the ability to calculate the financial result of the decision he must make. A new multi-criteria decision making with cost criterion analysed at the final stage (MCDM-CCAF) method is developed based on principle of Pareto optimal decisions. It is proposed to exclude the cost criterion from the MCDM analysis and consider it at the final phase of the decision-making process. It is illustrated by example solutions with consideration of cost criterion and without it. It is proposed to apply the invented post-processing method to all MCDM analyses where the cost criterion of analysed variants is considered.
In recent years, changes in demographic structure have been observed worldwide. To sustain the growing population of elderly people with special needs, homes need a radical rethink both in designing ...new houses and in retrofitting new solutions to existing houses. Designs that facilitate aging in place, designs that maintain thermal comfort, and designs that have net-zero energy demands and low to zero to negative carbon footprints are needed. The article discusses the issues of construction for the elderly. The trends in the demographic development of society in selected countries are presented. Additionally, information on the housing stock for elderly people in Poland is provided. The carbon dioxide emission limits to mitigate climate change make it necessary to find an alternative to concrete and steel, traditional construction materials. In this context, Cross Laminated Timber (CLT) fulfills the sustainability requirements. However, to select the suitable panel a detailed analysis of timber characteristics is required. It is necessary to evaluate mechanical properties in bending, tension, compression, and shear. Since the mechanical properties of certain types of wood differ, their proper selection is challenging. The multi-criteria analysis could address this. In this article, four wood species, spruce, oak, ash, and beech, were evaluated using the Analytic Hierarchy Process (AHP) analysis. Based on the type of construction elements and their functions, analyses were using six mechanical properties as criteria. The optimal type of wood was indicated.
The present work describes the complexation of the anti-inflammatory sialorphin derivative Pal-Lys-Lys-Gln-His-Asn-Pro-Arg (palmitic ...acid-lysine-lysine-glutamine-histidine-asparagine-proline-arginine) with Cu(II) ions in an aqueous solution, at a temperature of 25.0 ± 0.1 °C, over the whole pH range. The complexing properties were characterized by potentiometric and UV-Vis spectrophotometric methods. The potentiometric method was used to calculate the logarithms of the overall stability constants (log
) and the values of the stepwise dissociation constants (p
) of the studied complexes. The percentage of each species formed in an aqueous solution was estimated from the species distribution curve as a function of pH. The absorbance (
) and molar absorption coefficient (
) values for the Cu(II)-sialorphin derivative system were determined with UV-Vis spectroscopy. Our studies indicate that the sialorphin derivative forms stable complexes with Cu(II) ions, which may lead to future biological and therapeutic applications.
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