Strength Properties of Structural Glulam Elements from Pine (Pinus sylvestris L.) Timber Reinforced in the Tensile Zone with Steel and Basalt Rods

The study analyzed potential applicability for asymmetric reinforcement of glulam beams using materials with a higher modulus of elasticity. Reinforcement elements included smooth and ribbed steel rods as well as basalt rods. These rods were placed only in the tensile zone, assuming that they will not only impart increased rigidity but first of all will reduce the scatter of bending strength values. What is significant, tests were conducted on timber with defects, as it is most commonly used in industrial practice. Analyses showed that this provides an increase in rigidity close to the assumed level. A significant increase in strength was observed. The manufactured beams reinforced with steel and basalt rods were characterized by mean bending strength amounting to 54 and 47 N/mm², respectively. However, no significant improvement was found in the scatter of the observed variable. Beams reinforced with steel exhibit a 20% higher strength than unreinforced beams. The lower strength of beams reinforced with basalt bars may be related to the lower modulus of elasticity of the basalt itself.     

Thermal,Spectroscopy and Luminescent Characterization of Hybrid PMMA/Lanthanide Complex Materials

Novel hybrid materials based on the poly(methyl methacrylate) (PMMA) matrix and lanthanide(III) carboxylates Eu:2,6-DClB and Tb:2,6-DClB were synthesized and carefully analyzed in the context of their potential application in optically active polymer-based optical fibers. To determine the usefulness of the obtained materials, a careful thermal, mass spectroscopy, and optical characterization was performed, focusing on the features critical for the technology of optical fiber processing. In addition, the luminescent features of both lanthanide complexes and the resulting hybrid composites were carefully investigated to identify the processes responsible for light emission and to analyze the influence of the PMMA host on light emission intensity and spectral characteristics. The obtained results showed that both lanthanide carboxylate complexes exhibited intense luminescence in the red and green spectral range, typical of europium and terbium dopants, and that those features were well preserved after introducing them into the PMMA polymer. Thermal analysis also proved that introducing the luminescent additives did not significantly affect the thermal properties of both hybrid materials, thus enabling further processing into the form of optical fibers.     

Bone Density Micro-CT Assessment during Embedding of the Innovative Multi-Spiked Connecting Scaffold in Periarticular Bone to Elaborate a Validated Numerical Model for Designing Biomimetic Fixation of Resurfacing Endoprostheses

Our team has been working for some time on designing a new kind of biomimetic fixation of resurfacing endoprostheses, in which the innovative multi-spiked connecting scaffold (MSC-Scaffold) that mimics the natural interface between articular cartilage and periarticular trabecular bone in human joints is the crucial element. This work aimed to develop a numerical model enabling the design of the considered joint replacement implant that would reflect the mechanics of interacting biomaterials. Thus, quantitative micro-CT analysis of density distribution in bone material during the embedding of MSC-Scaffold in periarticular bone was applied. The performed numerical studies and corresponding mechanical tests revealed, under the embedded MSC-Scaffold, the bone material densification affecting its mechanical properties. On the basis of these findings, the built numerical model was modified by applying a simulated insert of densified bone material. This modification led to a strong correlation between the re-simulation and experimental results (FVU = 0.02). The biomimetism of the MSC-Scaffold prototype that provided physiological load transfer from implant to bone was confirmed based on the Huber–von Mises–Hencky (HMH) stress maps obtained with the validated finite element (FE) model of the problem. The micro-CT bone density assessment performed during the embedding of the MSC-Scaffold prototype in periarticular bone provides insight into the mechanical behaviour of the investigated implant-bone system and validates the numerical model that can be used for the design of material and geometric features of a new kind of resurfacing endoprostheses fixation.     

Effects of cigarette smoking on bicarbonate and volume of duodenal contents

The effect of smoking on bicarbonate and volume of duodenal juice was studied. It was found that in the basal condition smoking produced significant decreases in bicarbonate content and volume of duodenal samples. On the contrary, during pancreatic stimulation with secretin at approximately 50% of maximal secretion, smoking resulted in significant increases in bicarbonate output and volume. Decrease in buffering power of duodenal juice in the basal condition can, at least partially, explain the causative relation of smoking and peptic ulcer disease.Supported in part by Ayerst Laboratories, New York.Boots Secretin was kindly donated by Dr. K. Cartwright of Boots Pure Drug Co. Ltd., Nottingham, England.     

The adverse effects of marijuana use: The present state and future directions

Marijuana is recently a subject of a global debate due to potential medical application of cannabis products and the progressive legalization of its recreational use. This situation leads to the need for access to comprehensive and reliable information about the effects of marijuana intake. Our review presents the actual state of knowledge regarding acute and chronic health effects generated by recreational marijuana use. Marijuana smoking can lead to structural and functional alterations in the central nervous system. These effects are especially significant and dangerous at the prenatal, child, and adolescence periods. In contrary to a common myth, cannabis does exhibit an addictive potency, albeit not a strong one. We discuss the “cannabis gateway hypothesis,” which suggests that marijuana use can be the first step before trying more dangerous drugs. However, drawing significant conclusions is difficult due to the strong impact of confounders and often unclear relationships among studied factors, especially in the socioeconomic context. Moreover, we point to the need for the unbiased assessment of the harm generated by marijuana in comparison with other drugs.     

Zapobieganie zakażeniom meningokokowym – jak stosować obecnie dostępne szczepionki

Authors have presented the current recommendations for the prevention of meningococcal infections. The epidemiological situation in Poland has been described and the use of currently available meningococcal vaccines has been discussed. The chemoprophylaxis for close contacts of all people with invasive meningococcal disease has been also presented.     

Magnetic Recording Method (MRM) for Nondestructive Evaluation of Ferromagnetic Materials

This paper proposes and experimentally investigates a novel nondestructive testing method for ferromagnetic elements monitoring, the Magnetic Recording Method (MRM). In this method, the inspected element must be magnetized in a strictly defined manner before operation. This can be achieved using an array of permanent magnets arranged to produce a quasi-sinusoidal magnetization path. The magnetic field caused by the original residual magnetization of the element is measured and stored for future reference. After the operation or loading, the magnetic field measurement is repeated. Analysis of relative changes in the magnetic field (for selected components) allows identifying applied stress. The proposed research methodology aims to provide information on the steel structure condition unambiguously and accurately. An interpretation of the results without referring to the original magnetization is also possible but could be less accurate. The method can be used as a standard technique for NDT (Non-Destructive Testing) or in structural health monitoring (SHM) systems.