Selective wear of cuttings elements of working organs of tillage machines with realization of self-sharpening effect

The clause of strengthening of cuttings elements is conditioning and realization of such selforganization process as a self-sharpening. Sharpening of horizontal and vertical cuttings elements of working organs of tillage machines (CE WOTM) is considered in many works, but not found out the terms of realization and nature of these processes in a sufficient measure. The processes of sharpening and blunting of CE WOTM are related mainly to the processes of wear. The change of type of CE in the process of wear is conditioned mainly a size and character of tearing down each of its bevel and by volume of destruction of cutting edge in the process of exploitation in the medium of soil and depends on character of co-operation in tribosystem " WOTM -soil"

Protein detection using hydrogel-based molecularly imprinted polymers integrated with dual polarisation interferometry

A polyacrylamide-based molecularly imprinted polymer (MIP) was prepared for bovine haemoglobin (BHb). A 3 mg/ml solution of BHb was injected over a dual polarisation interferometer (DPI) sensor to form a physisorbed layer typically of 3.5 ± 0.5 nm thickness. Onto the pre-adsorbed protein layer, MIP and NIP (non-imprinted polymer) were separately injected to monitor the interaction of BHb MIP or NIP particles under different loading conditions with the pre-adsorbed protein layer. In the case of NIP flowing of the protein layer, there was negligible surface stripping of the pre-adsorbed protein. When a protein-eluted sample of MIP particles was flowed over a pre-adsorbed protein layer on the sensor chip, the sensor detected significant decreases in both layer thickness and mass, suggestive that protein was being selectively bound to MIP after being stripped-off from the sensor surface. We also integrated thin-film MIPS for BHb and BSA onto the DPI sensor surface and were able to show that whereas BHb bound selectively and strongly to the BHb MIP thin film (resulting in a sustained increase in thickness and mass), the BHb protein only demonstrated transient and reversible binding on the BSA MIP. MIPs were also tested after biofouling with plasma or serum at various dilutions. We found that serum at 1/100 dilution allowed the MIP to still function selectively. This is the first demonstration of MIPs being integrated with DPI in the development of synthetic receptor-based optical protein sensors. © 2012 Elsevier B.V. All rights reserved

Висівні машини та системи на основі елементів пневмоніки

On the basis of the research results it is established that to increase the productivity and quality, as well as to reduce the work intensity of planting machines it is necessary to unite the metering and timing system on one principle – the principle of discrete action. The rational basis for this is using of control and power fluidic devices, and active distribution of pneumatic devices and pneumatic power systems. On this basis, pneumatic seeding systems on the row and one grain sowing were developed, which also allows distributing seeds differentially when this seeding technology is used for precision farming. На підставі результатів досліджень встановлено, що для підвищення продуктивності і якості, зниження енергоємності роботи посівних машин необхідно об'єднання висівного апарату і системи синхронізації на одному принципі – дискретної дії, а раціональною основою для цього є застосування керуючих і силових струменевих елементів, а також активних пневматичних розподільних пристроїв і пневматичної системи живлення. Виходячи з цього, розроблено пневмоструминні висіваючі системи для рядової і однозернової сівби, що також дозволяють диференційовано розподіляти насіння при сівбі по технології точного землеробства

Modelling inflammatory biomarker dynamics in a human lipopolysaccharide (LPS) challenge study using delay differential equations

Clinical studies in healthy volunteers challenged with lipopolysaccharide (LPS), a constituent of the cell wall of Gram-negative bacteria, represent a key model to characterize the Toll-like receptor 4 (TLR4)-mediated inflammatory response. Here, we developed a mathematical modelling framework to quantitatively characterize the dynamics and inter-individual variability of multiple inflammatory biomarkers in healthy volunteer LPS challenge studies. Data from previously reported LPS challenge studies were used, which included individual-level time-course data for tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), interleukin 8 (IL-8) and C-reactive protein (CRP). A one-compartment model with first-order elimination was used to capture the LPS kinetics. The relationships between LPS and inflammatory markers was characterized using indirect response (IDR) models. Delay differential equations were applied to quantify the delays in biomarker response profiles. For LPS kinetics, our estimates of clearance and volume of distribution were 35.7 L h(-1) and 6.35 L, respectively. Our model adequately captured the dynamics of multiple inflammatory biomarkers. The time delay for the secretion of TNF-alpha, IL-6 and IL-8 were estimated to be 0.924, 1.46 and 1.48 h, respectively. A second IDR model was used to describe the induced changes of CRP in relation to IL-6, with a delayed time of 4.2 h. The quantitative models developed in this study can be used to inform design of clinical LPS challenge studies and may help to translate preclinical LPS challenge studies to humans.Pharmacolog

On the structure and oxygen transmission rate of biodegradable cellulose nanobarriers

Cellulose nanofibrils have been proposed for novel barrier concepts, based on their capability to form smooth, strong and transparent films, with high oxygen barrier properties. A series of cellulose-based films were manufactured and tested with respect to their oxygen transmission rate (OTR) capabilities. The obtained OTR levels were considerably better than the levels recommended for packaging applications. Part of the nanofibrillated material applied in this study was produced with 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO) mediated oxidation as pretreatment. Films made of TEMPO-pretreated samples yielded lower OTR values. The minimum obtained OTR value was 3.0 mL m-2 day-1 atm-1 with a corresponding oxygen permeability of 0.04 mL mm m-2 day-1 atm-1, tested at 50% relative humidity. The good barrier properties are due to the compact and dense structure of the films, as revealed by field-emission scanning electron microscopy. A relationship between OTR and the structure of the corresponding nanofibril-based films was confirmed

Physiologically based modelling framework for prediction of pulmonary pharmacokinetics of antimicrobial target site concentrations

Prediction of antimicrobial target-site pharmacokinetics is of relevance to optimize treatment with antimicrobial agents. A physiologically based pharmacokinetic (PBPK) model framework was developed for prediction of pulmonary pharmacokinetics, including key pulmonary infection sites (i.e. the alveolar macrophages and the epithelial lining fluid).\nThe modelling framework incorporated three lung PBPK models: a general passive permeability-limited model, a drug-specific permeability-limited model and a quantitative structure-property relationship (QSPR)-informed perfusion-limited model. We applied the modelling framework to three fluoroquinolone antibiotics. Incorporation of experimental drug-specific permeability data was found essential for accurate prediction.\nIn the absence of drug-specific transport data, our QSPR-based model has generic applicability. Furthermore, we evaluated the impact of drug properties and pathophysiologically related changes on pulmonary pharmacokinetics. Pulmonary pharmacokinetics were highly affected by physiological changes, causing a shift in the main route of diffusion (i.e. paracellular or transcellular). Finally, we show that lysosomal trapping can cause an overestimation of cytosolic concentrations for basic compounds when measuring drug concentrations in cell homogenate.\nThe developed lung PBPK model framework constitutes a promising tool for characterization of pulmonary exposure of systemically administrated antimicrobials.Pharmacolog

Measurement of the adhesion between single melamine-formaldehyde resin microparticles and a flat fabric surface using AFM

An understanding of the adhesion of microparticles, particularly microcapsules, containing a functional component to a fabric surface is crucial to an effective application of this component to the fibre. Fabric surface is very rough; hence, direct measurement of the adhesion of single microparticles to surfaces with a roughness greater than the particle diameter is difficult. In the study reported here, cotton films were generated by dissolving cotton powder in an organic solvent and their properties including surface roughness, thickness, contact angle and purity were characterised. The adhesive forces between single melamineformaldehyde (MF) resin microparticles and a cotton film under ambient conditions with a relative humidity of above 40% were measured using atomic force microscopy; they are considered to be dominated by capillary forces. It was found that there was little adhesion between a MF microparticle and a cotton film in an aqueous solution of sodium dodecylbenzene sulphonate as surfactant. Repulsion between them was observed, but it reduced with increase in the surfactant concentration and decrease in the pH of the solution. The repulsion contributions are thought to originate mainly from electrostatic repulsion. It is believed that the studies on the adhesion between single MF microparticles and a cotton film under ambient conditions or dispersed in surfactant solutions, are beneficial to the attempts to enhance the adhesion of microcapsules to fabric surfaces via a modification of their surface composition and morphology

Comparative tissue transcriptomics reveal prompt inter-organ communication in response to local bacterial kidney infection

<p>Abstract</p> <p>Background</p> <p>Mucosal infections elicit inflammatory responses via regulated signaling pathways. Infection outcome depends strongly on early events occurring immediately when bacteria start interacting with cells in the mucosal membrane. Hitherto reported transcription profiles on host-pathogen interactions are strongly biased towards <it>in vitro </it>studies. To detail the local <it>in vivo </it>genetic response to infection, we here profiled host gene expression in a recent experimental model that assures high spatial and temporal control of uropathogenic <it>Escherichia coli </it>(UPEC) infection within the kidney of a live rat.</p> <p>Results</p> <p>Transcriptional profiling of tissue biopsies from UPEC-infected kidney tissue revealed 59 differentially expressed genes 8 h post-infection. Their relevance for the infection process was supported by a Gene Ontology (GO) analysis. Early differential expression at 3 h and 5 h post-infection was of low statistical significance, which correlated to the low degree of infection. Comparative transcriptomics analysis of the 8 h data set and online available studies of early local infection and inflammation defined a core of 80 genes constituting a "General tissue response to early local bacterial infections". Among these, 25% were annotated as interferon-γ (IFN-γ) regulated. Subsequent experimental analyses confirmed a systemic increase of IFN-γ in rats with an ongoing local kidney infection, correlating to splenic, rather than renal <it>Ifng </it>induction and suggested this inter-organ communication to be mediated by interleukin (IL)-23. The use of comparative transcriptomics allowed expansion of the statistical data handling, whereby relevant data could also be extracted from the 5 h data set. Out of the 31 differentially expressed core genes, some represented specific 5 h responses, illustrating the value of comparative transcriptomics when studying the dynamic nature of gene regulation in response to infections.</p> <p>Conclusion</p> <p>Our hypothesis-free approach identified components of infection-associated multi-cellular tissue responses and demonstrated how a comparative analysis allows retrieval of relevant information from lower-quality data sets. The data further define marked representation of IFN-γ responsive genes and a prompt inter-organ communication as a hallmark of an early local tissue response to infection.</p

Rheological and biological properties of a hydrogel support for cells intended for intervertebral disc repair

<p>Abstract</p> <p>Background</p> <p>Cell-based approaches towards restoration of prolapsed or degenerated intervertebral discs are hampered by a lack of measures for safe administration and placement of cell suspensions within a treated disc. In order to overcome these risks, a serum albumin-based hydrogel has been developed that polymerizes after injection and anchors the administered cell suspension within the tissue.</p> <p>Methods</p> <p>A hydrogel composed of chemically activated albumin crosslinked by polyethylene glycol spacers was produced. The visco-elastic gel properties were determined by rheological measurement. Human intervertebral disc cells were cultured <it>in vitro </it>and <it>in vivo </it>in the hydrogel and their phenotype was tested by reverse-transcriptase polymerase chain reaction. Matrix production and deposition was monitored by immuno-histology and by biochemical analysis of collagen and glycosaminoglycan deposition. Species specific <it>in situ </it>hybridization was performed to discriminate between cells of human and murine origin in xenotransplants.</p> <p>Results</p> <p>The reproducibility of the gel formation process could be demonstrated. The visco-elastic properties were not influenced by storage of gel components. <it>In vitro </it>and <it>in vivo </it>(subcutaneous implants in mice) evidence is presented for cellular differentiation and matrix deposition within the hydrogel for human intervertebral disc cells even for donor cells that have been expanded in primary monolayer culture, stored in liquid nitrogen and re-activated in secondary monolayer culture. Upon injection into the animals, gels formed spheres that lasted for the duration of the experiments (14 days). The expression of cartilage- and disc-specific mRNAs was maintained in hydrogels <it>in vitro </it>and <it>in vivo</it>, demonstrating the maintenance of a stable specific cellular phenotype, compared to monolayer cells. Significantly higher levels of hyaluronan synthase isozymes-2 and -3 mRNA suggest cell functionalities towards those needed for the support of the regeneration of the intervertebral disc. Moreover, mouse implanted hydrogels accumulated 5 times more glycosaminoglycans and 50 times more collagen than the <it>in vitro </it>cultured gels, the latter instead releasing equivalent quantities of glycosaminoglycans and collagen into the culture medium. Matrix deposition could be specified by immunohistology for collagen types I and II, and aggrecan and was found only in areas where predominantly cells of human origin were detected by species specific <it>in situ </it>hybridization.</p> <p>Conclusions</p> <p>The data demonstrate that the hydrogels form stable implants capable to contain a specifically functional cell population within a physiological environment.</p