Hydraulic Vehicle Damper Controlled by Piezoelectric Valve.

In this paper, an original construction of a vehicle vibration damper controlled by means of a valve based on piezoelectric actuator is presented and investigated. The presented valve allows us to control dissipation characteristics of the damper faster than in other solutions adjusting the size of the gap through which the oil flows between the chambers of the damper. The article also presents the results of the experimental investigation of the above-mentioned damper showing the possibility of changing the value of the damping force five times in about 10 ms by changing the voltage supplying the piezoelectric actuator. Based on these results, dissipative characteristics were determined which enabled the identification of the parameters of the damper numerical model. The article also presents the results of numerical investigations a vehicle model equipped with the developed dampers. The results showed that the developed damper controlled by the use of the piezoelectric actuator can significantly affect vehicle traffic safety by reducing the variation of vertical forces acting on the wheels. The results obtained are so promising that the authors undertook preparations to conduct road tests of a vehicle equipped with the developed dampers.

Studies on Wear of a Milling Chuck for a Production Line of Specialized Elements Used in Lockstitch Machines.

The study aims to determine the wear intensity of selected milling chuck assembly surfaces covered with a protective DLC (Diamond Like Carbon) coating, used on the production line for elements of selected lockstitch machines, and to analyze the stress distributions in the object fixed with such a chuck for the characteristic load systems of this object during its processing. A model of the workpiece was developed using the finite element method. The boundary conditions, including the load and the method of clamping the workpiece, resulted from the parameters of the milling process and the geometric configuration of the milling chuck. Stress distributions in the workpiece for specific milling parameters and for various configurations of the milling chuck holding the workpiece are included in the article. The model experimental studies of wear were conducted in the contact zone between two surfaces covered with DLC: one on the element of the milling chuck pressing the workpiece and the other on the eccentric cams of this holder. The obtained wear values and shapes for the worn surfaces are also shown. The wear intensities for the steel plunger fins modelling swivel arm of the holder were by an order higher than those of corresponding steel shaft shoulders modelling eccentric cam of the holder. The linear wear intensities for these mating components may be expressed in terms of a function of average contact pressure and sliding speed in a corresponding contact zone. The indentation of eccentric cam into mating surface of the swivel arm of the holder increased nonlinearly with the enhancement of number of cycles of the eccentric cam.

Non-linear method of determining vehicle pre-crash speed based on tensor B-spline products with probabilistic weights - Intermediate Car Class.

In the following study we consider the Intermediate Car Class. We apply a novel non-linear method, where the work W of car deformation is defined as an algebraic function of deformation ratio Cs. We use the data from the NHTSA (National Highway Traffic Safety Administration) database comprising numerous frontal crash tests. On the basis of this database, we determine the mathematical model parameters. In the so-called energetic approach, collisions are treated as non-elastic. The velocity threshold that defines the elastic collision was set to be 11km/h. Such an approach, which greatly simplifies our considerations, determines the linear dependence of energy lost during deformation on deformation coefficient Cs. The coefficient Cs is calculated as a weighted mean value of deformation points C1-C6. In this paper, the authors suggest a more precise non-linear method in order to determine the work of deformation.

Development of the rectal dosage form with silver-coated glass beads for local-action applications in lower sections of the gastrointestinal tract.

CONTEXT: Recent findings indicating the anti-inflammatory action of silver preparations through modulation of the gut microbiota and apoptosis of inflammatory cells predestine silver use in inflammatory bowel disease (IBD). OBJECTIVE: The aim of our study was to validate the possibility of effective silver release from silver-coated glass beads for anti-inflammatory local application in the lower sections of the gastrointestinal (GI) tract. MATERIALS AND METHODS: Silver-coated glass beads were prepared using magnetron method. Release of silver from the silver-coated glass bead surface was carried out in BIO-DIS reciprocating cylinder apparatus. Erosion of silver coating and indirect estimation of the silver release dynamics was assessed using scanning electron microscope. Rectal suppositories containing silver-coated glass beads were prepared using five different methods (M1-M5) and X-ray scanned for their composition. RESULTS AND DISCUSSION: The XR microanalysis and the chemical composition analysis evidenced for a rapid (within 30 min) release of nearly 50% of silver from the coating of the glass beads, which remained stable up to 24 h of incubation. The most homogeneous distribution of beads in the entire volume of the suppository was obtained for formulation M5, where the molten base was poured into mold placed in an ice bath, and the beads were added after 10 s. CONCLUSIONS: Our study is the first to present the concept of enclosing silver-coated glass beads in the lipophilic suppository base to attenuate inflammation in the lower GI tract and promises efficient treatment with reduced side effects.

Evaluation of anti-inflammatory effect of silver-coated glass beads in mice with experimentally induced colitis as a new type of treatment in inflammatory bowel disease.

BACKGROUND: Recent studies point at the anti-inflammatory action of silver through induction of apoptosis of inflammatory cells via oxidative stress, promotion of wound healing as well as antimicrobial effect. Our aim was to design a new formulation based on silver and validate its anti-inflammatory activity in the mouse models of colitis. METHODS: Silver-coated glass beads were prepared using a magnetron sputtering method and a standard magnetron sputtering gun equipped with pure silver target. Colitis was induced by the ic administration of TNBS into colon (to mimic Crohn's disease) and addition of DSS to drinking water (to imitate ulcerative colitis). Evaluation of inflammation was performed based on macroscopic and microscopic scoring, quantification of the myeloperoxidase activity and colonic microflora analysis. RESULTS: Silver-coated glass beads administered ic alleviated intestinal inflammation in mouse models of colitis, induced by TNBS and DSS. This alleviation of colitis resulted principally from changes in the gut microflora. The anti-inflammatory action of the new formulation was associated predominantly with the presence of the silver nanolayer on the beads, and to a lesser extent the size of glass polymer units. CONCLUSIONS: The application of the newly developed formulation employing silver-coated glass beads has the potential to be translated to clinical conditions for the efficient treatment of IBD.

Synthesis and evaluation of anti-inflammatory properties of silver nanoparticle suspensions in experimental colitis in mice.

The aim of our study was to investigate the effect of newly developed silver nanoparticle aqueous suspensions NanoAg1 and NanoAg2 in the mouse models mimicking ulcerative colitis and Crohn's disease. NanoAg1 and NanoAg2 were synthesized in aqueous medium with the involvement of tannic acid. To elucidate their anti-inflammatory activity, semi-chronic mouse models of inflammation induced by dextrane sulfate sodium addition to drinking water and intracolonic (i.c.) administration of 2,4,6-trinitrobenzenesulfonic acid were used. NanoAg1 and NanoAg2 (500 mg/dm3, 100 µl/animal, i.c., once daily) significantly ameliorated colitis in dextrane sulfate sodium- and 2,4,6-trinitrobenzenesulfonic acid-induced mouse models of colonic inflammation, as indicated by reduced macroscopic, ulcer and microscopic scores. The anti-inflammatory effect was dependent on the shape and diameter of silver nanoparticles, as indicated by weaker effect of NanoAg1 than NanoAg2. In addition, administration of NanoAg2, but not NanoAg1, modulated colonic microbiota, as indicated by reduced number of Escherichia coli and Clostridium perfringens, and increased number of Lactobacillus sp. Summarizing, NanoAg1 and NanoAg2 after administered i.c. effectively alleviate colitis in experimental models of ulcerative colitis and Crohn's disease in mice. Therefore, NanoAg1 and NanoAg2 administered i.c. have the potential to become valuable agents for the treatment of inflammatory bowel diseases.

Silver and other metals in the treatment of gastrointestinal diseases.

Disturbance in the functioning of the gastrointestinal (GI) tract can critically affect the health and even the life of the whole organism. Several factors, both exo- and endogenous may contribute to the dysregulation of homeostasis in the digestive system, including genetic background, ingestion of highly processed food, exposition to environmental pollution or chronic stress, and changes in gut microflora, to name just a few. An important number of these factors rely on metals, which often play a dual, stimulatory and inhibitory role in crucial physiological processes. In this paper, we focus on the structures incorporating silver, copper and other metals as future drugs against GI diseases. We critically review available literature for their effectiveness and potential application, and discuss clinical relevance of these findings.

Rhenium-coated glass beads for intracolonic administration attenuate TNBS-induced colitis in mice: Proof-of-Concept Study.

In search for novel effective treatments in inflammatory bowel diseases, a new strategy employing glass beads coated with rhenium nanolayer has been developed and validated in the mouse model of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis. Briefly, mice were randomly divided into 5 experimental groups: control (vehicle alone, Group 1); control treated with rhenium-coated glass beads (Group 2); TNBS (Group 3); TNBS treated with rhenium-coated glass beads (Group 4); and TNBS treated with uncoated glass beads (Group 5). Mice from Group 2, 4 and 5 were treated with respective beads (once daily, 5 beads / animal, i.c.) between D3-D6 post-TNBS/vehicle and evaluation of colonic damage was performed on D7, based on macroscopic scoring and clinical parameters. Severe colonic inflammation developed in post-TNBS mice (Group 3) [P <0.001 vs. control (Group 1) for macroscopic score], which was significantly attenuated by treatment with rhenium-coated glass beads (Group 4) [P <0.01 vs. TNBS (Group 3), for macroscopic score]. Neither rhenium-coated glass beads had any effect in control animals (Group 2), nor uncoated glass beads influenced TNBS-induced colitis (Group 5). In conclusion, a novel and attractive strategy for the treatment of colonic inflammation has been proposed; therapy with rhenium-coated glass beads already proved effective in the mouse model of TNBS-induced colitis, now requires further characterization in clinical conditions.