Health effects of exposure to chlorination by-products in swimming pools

Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming pools (water ingestion, skin absorption, and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports, and recreational attendance) and identify the main recommendations and unmet needs for research in this area.     

Shaping Physiological Indices,Swimming Technique,and Their Influence on 200m Breaststroke Race in Young Swimmers

The aim of this study was to investigate somatic properties and physiological capacity, and analyze kinematic parameters in the 200 m breaststroke swimming race. Twenty-seven male swimmers participated in the study. They were 15.7±1.98 years old. Their average height was 1.80 ± 0.02 m and lean body mass (LBM) was 62.45 ± 8.29 kg. Physiological exercise capacity was measured in two separate 90 sec. all-out tests, one for the arms and second for legs. During the tests total work of arm cranking (TWAR) and cycling (TWLG) as well as peak of VO₂ for arm (VO_2peakAR) and leg (VO_2peakLG) were measured. The underwater swimmers body movements were recorded during the all-out swimming 200m breaststroke speed test using an underwater camera installed on a portable trolley. The swimming kinematic parameters and propulsive or non-propulsive movement phases of the arms and legs as well as average speed (V200), surface speed (V200surface) and swimming speed in turn zones (V200turns) were extracted. V200surface was significantly related to the percentage of leg propulsion and was shown to have large effect on VO_2peakLG in the Cohen analysis. V200turns depended significantly on the indicators of physiological performance and body structure: TWAR, VO_2peak LG and LBM, LBM, which in turn strongly determined the measured results of TWAR, TWLG, VO_2peakAR and VO_2peakLG. The V200turns and V200surface were strongly associated with V200, 0.92, p < 0.001 and 0.91, p < 0.001 respectively. In each lap of the 200m swimming there was an increased percentage of propulsion of limb movement observed simultaneously with a reduction in the gliding phase in the breaststroke cycles.

Key points

• This study investigated the influence of the selected indicators of somatic properties and physiological capacity as well kinematic and coordination parameters on breaststroke swimming.
• In this observations the body’s functional capacity have an important impact on achieving good breaststroke swimming results, the V₂₀₀ was moderately associated on VO₂peakLG, moreover, separate V₂₀₀turns depended with VO₂peakLG and on LBM and TWAR.
• The speed of surface breaststroke swimming - V₂₀₀surface similarly as V₂₀₀turns had a very strong influence on the end result of V_{200 ,} 0.91, p<0.001 and 0.92, p<0.001 respectively.
• The ability to swim fast on the surface (V₂₀₀surface) was positively and significantly associated with the percentage time of propulsion generation -LP in the breaststroke cycle.

Key words: Breaststroke swimming, physiological indices, lean body mass, kinematic indices     

Very small embryonic-like stem cells: characterization, developmental origin, and biological significance

Bone marrow (BM) was, for many years, primarily envisioned as the "home organ" of hematopoietic stem cells (HSC). Augmenting evidence demonstrates, however, that BM, in addition to HSC, also contains a heterogeneous population of non-HSC. Recently, our group identified in BM and other adult tissues a population of very small embryonic-like stem cells (VSELs), which express several markers characteristic for pluripotent stem cells that are characteristic for epiblast/germ line-derived stem cells. Thus, we hypothesize that VSELs are a population of epiblast-derived cells that are deposited during early gastrulation in developing tissues/organs and play an important role in turnover of tissue-specific/committed stem cells. In this context, VSELs deposited in BM can give rise to long-term repopulating HSC. VSELs could be also mobilized into peripheral blood (PB), and the number of these cells circulating in PB increases during stress and tissue/organ injuries. Finally, we envision that in pathological situations VSELs are involved in development of some malignancies (e.g., teratomas, germinal tumors).     

Mechanical Properties of Different Nanopatterned TiO2 Substrates and Their Effect on Hydrothermally Synthesized Bioactive Hydroxyapatite Coatings

Nanotechnology is a very attractive tool for tailoring the surface of an orthopedic implant to optimize its interaction with the biological environment. Nanostructured interfaces are promising, especially for orthopedic applications. They can not only improve osseointegration between the implant and the living bone but also may be used as drug delivery platforms. The nanoporous structure can be used as a drug carrier to the surrounding tissue, with the intention to accelerate tissue–implant integration as well as to reduce and treat bacterial infections occurring after implantation. Titanium oxide nanotubes are promising for such applications; however, their brittle nature could be a significantly limiting factor. In this work, we modified the topography of commercially used titanium foil by the anodization process and hydrothermal treatment. As a result, we obtained a crystalline nanoporous u-shaped structure (US) of anodized titanium oxide with improved resistance to scratch compared to TiO₂ nanotubes. The US titanium substrate was successfully modified with hydroxyapatite coating and investigated for bioactivity. Results showed high bioactivity in simulated body fluid (SBF) after two weeks of incubation.     

Influence of the Selected Physical Modifier on the Dynamical Behavior of the Polymer Composites Used in the Aviation Industry

In this research, an analysis of polymer composite with the matrix of L285-cured hardener H286 and six reinforcement layers of carbon fabric GG 280 T was provided. It involved a comparison of the dynamical behavior responses for three cases of composite structures in the context of the presence of the mass share modifier. The samples with the addition of a physical modifier with varying mass percentages were investigated by being subjected to dynamic tests with specific parameters, i.e., constant excitation amplitude and vibration frequency in the vicinity of the base resonance zone. The analysis allowed for indicating the relationship between the composition of the prepared composites and their dynamic response via stiffness characteristics. In addition, the investigation resulted in determining the range of harmful dynamical operating conditions, which may contribute to damage to the composite structures.     

Magnetic Properties and the Electronic Structure of the Gd0.4Tb0.6Co2 Compound

We report on the comprehensive experimental and theoretical studies of magnetic and electronic structural properties of the Gd_0.4Tb_0.6Co₂ compound crystallization in the cubic Laves phase (C15). We present new results and compare them to those reported earlier. The magnetic study was completed with electronic structure investigations. Based on magnetic isotherms, magnetic entropy change (ΔS_M) was determined for many values of the magnetic field change (Δμ₀H), which varied from 0.1 to 7 T. In each case, the ΔS_M had a maximum around room temperature. The analysis of Arrott plots supplemented by a study of temperature dependency of Landau coefficients revealed that the compound undergoes a magnetic phase transition of the second type. From the M(T) dependency, the exchange integrals between rare-earth R-R (J_RR), R-Co (J_RCo), and Co-Co (J_CoCo) atoms were evaluated within the mean-field theory approach. The electronic structure was determined using the X-ray photoelectron spectroscopy (XPS) method as well as by calculations using the density functional theory (DFT) based Full Potential Linearized Augmented Plane Waves (FP-LAPW) method. The comparison of results of ab initio calculations with the experimental data indicates that near T_C the XPS spectrum collects excitations of electrons from Co3d states with different values of exchange splitting. The values of the magnetic moment on Co atoms determined from magnetic measurements, estimated from the XPS spectra, and results from ab initio calculations are quantitatively consistent.     

B‐cell modulation of dendritic‐cell function: Signals from the far side

An appropriate immune response against a specific pathogen requires finely orchestrated interactions between the various cell populations within the immune system. At the same time, immunological tolerance to self must be maintained. DCs play an essential role in achieving these dual requisites. They coordinate adaptive immunity by integrating signals directly emanating from both infectious agents and cells of the immune system. Many such signals, especially those from innate cells and T cells, have been extensively characterized. In contrast, little is known about how B cells modulate function of DCs. B cells produce a variety of cytokines, including IL‐10 and IL‐6, which are known to influence DC function. In addition, Igs constitute the major secretory products of terminally differentiated B cells (plasma cells). DCs express various types of receptors for binding Ig, such as Fc receptors and C‐type lectin receptors. In accordance, Igs can regulate DC function depending on the receptors engaged. Here, we review the emerging immunomodulatory role of cytokines and Ig secreted by B cells. We discuss the evidence for how these B‐cell‐derived factors may shape the adaptive immune response by directly acting on DCs.