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Educating future youth workers is a particular challenge for higher education. It results not only in the acquisition of basic knowledge and skills, but also in the implementation of the glocal perspective. In this aspect, the process of internationalization of higher education is a key element enabling optimal shaping of future youth workers’ vocational identity. The article presents an international strategic partnership project enabling such activities in the area of bachelor’s studies. Its theoretical layer (Positive Youth Development) and intellectual outputs were presented. Moreover, learning, teaching and training activities, which are the result of the testing of the educational module, were introduced. The opportunity to participate in such international activities enables future social professionals to creatively approach youth problems at the local level using a broader perspective and mechanisms based not only on identifying risk and problems but also on resources and opportunities for positive development. The results worked out in the project can form the basis to develop learning, teaching and training activities for future youth workers outside partner universities.

This paper presents a concept and implementation of an infrared imaging sensor network for object localization and tracking. The sensor network uses multiple low-resolution (80× 80 pixels) microbolometric thermal cameras to detect, track and locate an object within the area of observation. The network uses information simultaneously acquired from multiple sensors to detect and extract additional information about object’s location. The use of thermal-imaging systems responsive to objects’ natural infrared radiation, makes the system resistant to external illumination and environmental conditions. At the same time, the use of infrared sensor requires application of specially designed, dedicated image processing techniques appropriate for this kind of sensor. The paper describes: image processing techniques, means of object localization, accuracy measurements, comparison to other known solutions and final conclusions.

Monolithic high contrast gratings (MHCGs) composed of a one-dimensional grating patterned in a monolithic layer provide up to 100% optical power reflectance and can be fabricated in almost any semiconductor and dielectric material used in modern optoelectronics. MHCGs enable monolithic integration, polarization selectivity, and versatile phase tuning. They can be from 10 to 20 times thinner than distributed Bragg reflectors. The subwavelength dimensions of MHCGs significantly reduce the possibility of ensuring the smoothness of the sidewalls of the MHCG stripes and make precise control of the shape of the MHCG stripe cross-section difficult during the etching process. The question is then whether it is more beneficial to improve the etching methods to obtain a perfect cross-section shape, as assumed by the design, or whether it is possible to find geometrical parameters that enable high optical power reflectance using the shape that a given etching method provides. Here, we present a numerical study supported by the experimental characterization of MHCGs fabricated in various materials using a variety of common surface nanometer-scale shaping methods. We demonstrate that MHCG stripes with an arbitrary cross-section shape can provide optical power reflectance of nearly 100%, which greatly relaxes their fabrication requirements. Moreover, we show that optical power reflectance exceeding 99% with a record spectral bandwidth of more than 20% can be achieved for quasi-Trapezoidal cross-sections of MHCGs. We also show that sidewall corrugations of the MHCG stripes have only a slight impact on MHCG optical power reflectance if the amplitude of the corrugation is less than 16% of the MHCG period. This level of stripe fabrication precision can be achieved using the most current surface etching methods. Our results are significant for the design and production of a variety of photonic devices employing MHCGs. The flexibility with regard to cross-section shape facilitates the reliable fabrication of highly reflective subwavelength grating mirrors. This in turn will enable the manufacture of monolithically integrated high-quality-factor optical micro-and nanocavity devices.

Wprowadzenie i cel: Witamina D3 jest jednym z najbardziej istotnych związkow endogennych syntetyzowanych w organizmie czlowieka. Pierwotnie jej niedobor powiązano z wystepowaniem krzywicy u dzieci. Jednakze liczne badania przeprowadzone w ciągu ostatnich dziesiecioleci wskazaly, ze witamina D3 ma duzo wieksze znaczenie, niz wcześniej przypuszczano. Celem niniejszej pracy byla analiza dostepnej literatury naukowej dotyczącej witaminy D3 i jej wplywu na zdrowie czlowieka. Metody przeglądu: W celu przeszukiwania bazy danych Pubmed uzyto nastepujących kombinacji slow kluczowych: [„vitamin D”] + [„synthesis”, „metabolism”, „receptor”, „epidemiology”, „deficiency”, „SARS-CoV-2”]. Po zastosowaniu kry-teriow wykluczających do przeglądu wybrano 67 publikacji Opis stanu wiedzy: Okolo 90% witaminy D3 jest wytwarzane w skorze w rezultacie ekspozycji na promieniowanie UVB. Po-zostala cześc jest dostarczana z zywnością lub suplementami diety. Postuluje sie, ze niedobor witaminy D3 jest obecnie jednym z najbardziej palących problemow zdrowotnych. Dane literaturowe wskazują, ze niedobor witaminy D3 powaznie zaburza homeostaze organizmu i zwieksza ryzyko powstawania niektorych nowotworow, chorob sercowo-naczyniowych, a takze cukrzycy typu 2. W związku z wybuchem pandemii koronawirusa SARS-CoV-2 w 2019 roku rozpoczeto badania kliniczne dotyczące wplywu witaminy D3 na podatnośc na infekcje i przebieg choroby. Stwierdzono jej korzystny wplyw w przeciwdzialaniu zakazeniom i lagodzeniu skutkow COVID-19. Podsumowanie: Wraz z postepem medycyny zrozumiano, jak wazna dla prawidlowego funkcjonowania organizmu jest witamina D3 i jakie konsekwencje zdrowotne powoduje jej niedobor. Dlatego z punktu widzenia zdrowia publicznego istotne jest powszechne uświadomienie spoleczenstwa o znaczeniu tej witaminy dla zdrowia i zaletach jej regularnego przyjmowania.Alternate abstract: Introduction and objective: Vitamin D3 is one of the most essential endogenous compounds synthesized in the human body. Originally, its deficiency was associated with the occu-rrence of rickets in children. However, a number of studies carried out over the last decades indicated that vitamin D3 is much more important than previously thought. The aim of this study was to analyze the available scientific literature on vitamin D3 and its effects on human health. Review methods: The following combinations of key words were used to search the Pubmed database: [vitamin D] + [synthesis, metabolism, receptor, epidemiology, deficiency, SARS-CoV-2]. After applying exclusion criteria, 67 articles were selected for review. Abbreviated description of the state of knowledge: About 90% of vitamin D3 is produced in the skin as a result of exposure to UVB radiation. The remaining portion is supplied from food or dietary supplements. It is postulated that vitamin D3 deficiency is one of the most pressing health problems today. Literature data indicate that vitamin D3 deficiency severely disrupts the body’s homeostasis and increases the risk of certain cancers, cardiovascular diseases, and type 2 diabetes. Since the 2019 outbreak of the SARS-CoV-2 coronavirus pan-demic, clinical studies have been initiated on the effects of vitamin D3 on susceptibility to infection and disease course. It has been found to have beneficial effects in preventing infection and mitigating the effects of COVID-19. Summary: With the progress of medicine it has been under-stood how important vitamin D3 is for the proper functioning of the body and what health consequences its deficiency entails. Therefore, from the point of view of public health it is important to make the general public aware of the im-portance of this vitamin for health and the advantages of its regular intake.

The article presents a new concept of using thermography – steganography in thermography. Steganography is a technique of hiding information in a non-obvious way and belongs to the field of science related to information security. This article examines three examples of steganographic channels – covert communication channels that use thermal imaging devices in three different ways. The first proposed method uses the possibility of alternating the scene observed by the infrared camera in a way that additional information is included in the thermogram. The second method, called ThermoSteg, uses modification of one of the parameters of the thermal imaging camera (integration time) to embed the signal containing hidden information. The third method is based on digital thermograms and the methods of replacing dead pixels in them by creating the so-called zombie pixels carrying secretive information. Three methods have been implemented under real conditions and proven to work in practice.

The topic of this paper is an evaluation of developed sensor intended for navigation aid of unmanned aerial vehicles (UAVs). Its operation is based on processing images acquired with a thermal camera operating in the long-wave infrared band (LWIR) placed underneath a vehicle’s chassis. The vehicle’s spatial displacement is determined by analyzing movement of characteristic thermal radiation points (ground, forest, buildings, etc.) in pictures acquired by the thermal camera. Magnitude and direction of displacement is obtained by processing the stream of consecutive pictures with optical-flow based algorithm in real time. Radiation distribution analysis allows to calculate camera’s self-translation vector. Advantages of measuring translation based on thermal image analysis is lack of drift effect, resistance to magnetic field variations, low susceptibility to electromagnetic interference and change in weather conditions as compared to traditional inertial navigation sensors. As opposed to visible light situational awareness sensors, it offers operation in complete darkness (harsh weather, nights and indoors).The topic of this paper is an evaluation of developed sensor intended for navigation aid of unmanned aerial vehicles (UAVs). Its operation is based on processing images acquired from a thermal camera operating in the long wave infrared band (LWIR) placed underneath a vehicle’s chassis. The vehicle’s spatial displacement is determined by analyzing movement of characteristic thermal radiation points (ground, forest, buildings, etc.) in pictures acquired by the thermal camera. Magnitude and direction of displacement is obtained by processing the stream of consecutive pictures with optical-flow based algorithm in real time. Radiation distribution analysis allows to calculate camera’s self-translation vector. Advantages of measuring translation based on thermal image analysis is lack of drift effect, resistance to magnetic field variations, low susceptibility to electromagnetic interference and change in weather conditions as compared to traditional inertial navigation sensors. As opposed to visible light situational awareness sensors, it offers operation in complete darkness (harsh weather, nights and indoors).

In polariton microcavities, the upper polariton branch is often hardly observable in reflectivity or photoluminescence measurements, which hampers reliable determination of the vacuum Rabi splitting value. We studied the photoluminescence excitation of a semiconductor microcavity with eight embedded CdSe/(Cd,Mg)Se quantum wells and observed a maximum in the emission from the lower polariton branch when the energy of the excitation was tuned to that of the upper polariton branch. This indicates that, in microcavities, where the upper polariton branch is hardly observable but interbranch polariton relaxation is efficient, the Rabi splitting value can be determined based on the energy difference between the absorption and emission maxima in photoluminescence excitation measurements. The Rabi splitting value of the studied sample as determined by reflectivity measurements was 18 ± 2 meV. Strong coupling conditions allow us to observe lasing with a relatively low threshold of 0.24 kW cm−2.

Introduction and Objective Nuclear factor kappa B (NF-κB) signalling pathway plays a central role in the regulation of cellular response to stress. The aim of the study was to investigate the ability of silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), CdTe quantum dots (CdTeQDs) or their binary mixtures to stimulate NF-κB binding in HepG2 cells. A dual luciferase reporter system was used to investigate NF-κB binding. Material and methods Cells were transiently transfected with a firefly luciferase reporter system and Renilla luciferase expression plasmid as a transfection efficiency control. Twenty- four hours after transfection, the cells were treated with nanoparticles (10 μg/cm 3 AgNPs, 10 μg/cm 3 AuNPs, 3 μg/cm 3 CdTeQDs) or with 10 ng/cm 3 TNFα as a positive control. Six hours later, the cells were lysed and the activities of the luminescence of firefly and Renilla luciferases were measured using the Dual-Luciferase Reporter Assay System. Results AuNPs and CdTeQDs alone significantly inhibited NF-κB binding activity. Co-treatment with AgNPs and CdTeQDs resulted in an additive effect, whereas the presence of AgNPs diminished the inhibitory effect of AuNPs. Interestingly, significant antagonism was observed between AuNPs and CdTeQDs, suggesting a similar mode of action. Conclusions Comparison of the NF-κB binding activity induced by the mixtures of NPs suggests that in some cases NF-κB binding activity might differ from that observed for the NPs alone.

The proposed StegoFrameOrder (SFO) method enables the transmission of covert data in wireless computer networks exploiting non-deterministic algorithms of medium access (such as the distributed coordination function), especially in IEEE 802.11 networks. Such a covert channel enables the possibility of leaking crucial information outside secured network in a manner that is difficult to detect. The SFO method embeds hidden bits of information in the relative order of frames transmitted by wireless terminals operating on the same radio channel. The paper presents an idea of this covert channel, its implementation, and possible variants. The paper also discusses implementing the SFO method in a real environment and the experiments performed in the real-world scenario.

Metallic nanoparticles due to their small size and unique physico-chemical characteristics have found excellent applications in various branches of industry and medicine. Therefore, for many years a growing interest has been observed among the scientific community in the improvement of our understanding of the impact of nanoparticles on the living organisms, especially on humans. Considering the delicate structure of the central nervous systemit is one of the organs most vulnerable to the adverse effects of metallic nanoparticles. For that reason, it is important to identify the modes of exposure and understand the mechanisms of the effect of nanoparticles on neuronal tissue. In this review, an attempt is undertaken to present current knowledge about metallic nanoparticles neurotoxicity based on the selected scientific publications. The route of entry of nanoparticles is described, as well as their distribution, penetration through the cell membrane and the blood-brain barrier. In addition, a study on the neurotoxicity in vitro and in vivo is presented, as well as some of the mechanisms that may be responsible for the negative effects of metallic nanoparticles on the central nervous system. Graphical abstract: This review summarizes the current knowledge on the toxicity of metallic NPs in the brain and central nervous system of the higher vertebrates.

Exposure to pesticides leads to complex, long-lasting adverse effects on human health, and poses a substantial risk to those living in areas devoted to agriculture. Children are particularly vulnerable to the pesticide exposure, due to the developmental, dietary and physiological factors. Small body mass and typical exploratory behavior result in increased risk of intoxication. Thus, even exposure to low concentrations of pesticides, if of sufficient duration, may lead to permanent health disorders and limit their harmonious development. In this study 108 children, living in areas of an intense pesticide use and a control group (n = 92) of children from an agrotouristic area were investigated, whether DNA damage increased due to prolonged pesticide exposure. A presence of DNA breaks and oxidative damage to DNA bases, characterized as Fpg-sensitive sites, were detected by comet assay. Micronuclei (MN) formation was evaluated by cytokinesis-block MN assay. The exposure of children to pesticides resulted in increased number of MN in peripheral blood lymphocytes (P = 0.016), increased DNA strand breaks level (P = 0.002) and oxidative damage to DNA (P 0.001). Negative correlation was demonstrated between the level of DNA strand breaks and acetylcholinesterase (AChE) activity in exposed group. In conclusion, despite just environmental pesticide exposure in the test group of children, significant biological effects were detected.

W artykule przeanalizowano koncepcje teoretyczne oraz badania dotyczące zagadnienia kontaktów nieletnich z funkcjonariuszami policji zwracając uwagę na ich konfliktowy charakter. Poruszaną problematykę przeanalizowano z trzech perspektyw: środowiskowej, jednostkowej oraz sytuacyjnej. Analizując rolę czynników środowiskowych, szczególną rolę przypisano rodzinie oraz grupom rówieśniczym. Charakteryzując perspektywę jednostkową zwrócono uwagę na rolę wieku, płci oraz pochodzenia jako czynników rzutujących na relacje z policją. W kontekście sytuacyjnym zwrócono uwagę na opór, poczucie krzywdy jako czynniki prowadzące do intensyfikacji przebiegu interwencji. Podkreślono, że konfliktowy charakter relacji może prowadzić do eskalacji napięć skutkujących stosowaniem sankcji, wzrostem dystansu i oporu oraz naznaczeniem.

Multi-level exciton-polariton systems offer an attractive platform for studies of non-linear optical phenomena. However, studies of such consequential non-linear phenomena as polariton condensation and lasing in planar microcavities have so far been limited to two-level systems, where the condensation takes place in the lowest attainable state. Here, we report non-equilibrium Bose-Einstein condensation of exciton-polaritons and low threshold, dual-wavelength polariton lasing in vertically coupled, double planar microcavities. Moreover, we find that the presence of the non-resonantly driven condensate triggers interbranch exciton-polariton transfer in the form of energy-degenerate parametric scattering. Such an effect has so far been observed only under excitation that is strictly resonant in terms of the energy and incidence angle. We describe theoretically our time-integrated and time-resolved photoluminescence investigations by a set of rate equations involving an open-dissipative Gross-Pitaevskii equation. Our platform's inherent tunability is promising for construction of planar lattices, enabling three-dimensional polariton hopping and realization of photonic devices, such as two-qubit polariton-based logic gates., 8 pages, 5 figures

This public policy chapter analyses and discusses the provision of prison inmates with “wireless” communication with the outside world (Rule 63 of the United Nations Standard Minimum Rules for the Treatment of Prisoners (Nelson Mandela Rules). In the context of the 2030 United Nations Sustainable Development Goal (SDG) 16 to promote peaceful, just and inclusive societies, the chapter calls on the prison administration and non-governmental organisations authorised to assist in the rehabilitation and reintegration of inmates and ex-prisoners to jointly pursue through training, periodicals and special institutional publications the related SDGs’ action-oriented preventive content, with due regard to the group-oriented and individual respective resilience or vulnerability of inmates. Throughout the chapter, the authors seek to demonstrate the importance of the 2030 United Nations SDGs which aspire to transform the world so “no one will be left behind,” even if they stay behind prison bars, or behind others as one of the other kind of minority in an open multicultural society.

Skin acts as a mechanical barrier between human body and environment. Epidermal cells are regularly exposed to many physiological and environmental stressors, such as pesticides, like chlorpyrifos (CPS). It is recognised that CPS may affect metabolism of other exo- and endogenous substances by affecting enzyme activity and expression. This study aims to investigate the effect of CPS on expression of CYP27A1, CYP27B1 and CYP24A1, the enzymes involved in synthesis and metabolism of vitamin D

Silver nanoparticles (AgNPs) are used in many fields of industry and medicine. Despite the well-established antimicrobial activity, AgNPs are foreseen to be used as anticancer drugs due to the unusual feature&mdash, inability to induce drug resistance in cancer cells. The aim of the study was to assess biological activity of AgNPs against MDA-MB-436 cells. The cells were derived from triple-negative breast cancer, a type of breast cancer with poor prognosis and is particularly difficult to cure. AgNPs were toxic to MDA-MB-436 cells and the probable mechanism of toxicity was the induction of oxidative stress. These promising effects, giving the opportunity to use AgNPs as an anti-cancer agent should, however, be treated with caution in the light of further results. Namely, the treatment of MDA-MB-436 cells with AgNPs was associated with the increased secretion of several cytokines and chemokines, which were important in breast cancer metastasis. Finally, changes in the actin cytoskeleton of MDA-MB-436 cells under the influence of AgNPs treatment were also observed.

Coupling of quantum emitters in a semiconductor relies, generally, on short-range dipole-dipole or electronic exchange type interactions. Consistently, energy transfer between exciton states, that is, electron-hole pairs bound by Coulomb interaction, is limited to distances of the order of 10~nm. Here, we demonstrate polariton-mediated coupling and energy transfer between excitonic states over a distance exceeding 2~$\mu$m. We accomplish this by coupling quantum well-confined excitons through the delocalized mode of two coupled optical microcavities. Use of magnetically doped quantum wells enables us to tune the confined exciton energy by the magnetic field and in this way to control the spatial direction of the transfer. Such controlled, long-distance interaction between coherently coupled quantum emitters opens possibilities of a scalable implementation of quantum networks and quantum simulators based on solid-state, multi-cavity systems., Comment: 4 figures

In this article, through reference to the theories of multilingualism, we would like to outline issues pertaining to the bilingual upbringing of children in bicultural families and their education in Polish schools. Referring to research (interviews) with parents of bilingual children from Warsaw, we will point to strategies employed by parents who communicate with their children in two or three languages. We will also draw attention to difficulties connected with dominant and non-dominant languages (the case of grandparents). In the second section, we will discuss diverse school environments and language in schools where bilingual children function. We also explore the argumentation of both parents deciding to enrol their bilingual children in state schools with Polish as the language of instruction, and those opting for enrolment in private schools with English as the language of instruction or social schools. The research material was collected among parents of bicultural and bilingual children living in Poland, the Mazovian voivodship, including the capital city of Warsaw. The group presented consists of multinational families in which one parent (most frequently the father) comes from a country from the African continent. Keywords: multilingualism, bilingualism, the upbringing process in multinational families, school education, communication

Matrix metallopeptidases, commonly known as matrix metalloproteinases (MMPs), are a group of proteolytic enzymes whose main function is the remodeling of the extracellular matrix. Changes in the activity of these enzymes are observed in many pathological states, including cancer metastases. An increasing body of evidence indicates that nanoparticles (NPs) can lead to the deregulation of MMP expression and/or activity both in vitro and in vivo. In this work, we summarized the current state of knowledge on the impact of NPs on MMPs. The literature analysis showed that the impact of NPs on MMP expression and/or activity is inconclusive. NPs exhibit both stimulating and inhibitory effects, which might be dependent on multiple factors, such as NP size and coating or a cellular model used in the research.

The article presents a new concept—steganography in thermography. Steganography is a technique of hiding information in a non-obvious way and belongs to sciences related to information security. The proposed method, called ThermoSteg, uses a modification of one of the parameters of the thermal imaging camera—integration time—to embed the signal containing hidden information. Integration time changing makes the microbolometer array heat up while reading the sensors. The covert information can be extracted from the stream of thermograms recorded by another thermal camera that observes the first one. The covert channel created with the ThermoSteg method allows the transmission of covert data using a thermal sensor as a wireless data transmitter. This article describes a physical phenomenon that is exploited by the ThermoSteg method and two proposed methods of covert data extraction, and presents the results of experiments.

Artykuł ma celu przybliżenie tematyki związanej z występującymi w polskim prawie karnym materialnym prawnymi aspektami typów kwalifi kowanych przestępstwa zabójstwa. Niewątpliwie jest ono najpoważniejszym z przestępstw godzącym w największą wartość, jaką jest życie ludzkie. Systematyczne ujęcie problemu umożliwiło w sposób przejrzysty ukazanie ustawowych znamion przestępstwa określonego w art. 148 § 2 i 3 kodeksu karnego oraz okoliczności wpływających na prawidłową kwalifi kację prawną. W opracowaniu jednocześnie wykazano okoliczności wpływające na orzekanie najsurowszych kar w przypadku morderstwa.

Lasing relies on light amplification in the active medium of an optical resonator. There are three lasing regimes in the emission from a quantum well coupled to a semiconductor microcavity. Polariton lasing in the strong light–matter coupling regime arises from the stimulated scattering of exciton-polaritons. Photon lasing in the weak coupling regime relies on either of two mechanisms: the stimulated recombination of excitons, or of an electron–hole plasma. So far, only one or two out of these three regimes have been reported for a given structure, independently of the material system studied. Here, we report on all three lasing regimes and provide evidence for a three-threshold behavior in the emission from a photonic trap in a Se/Te-based planar microcavity comprising a single CdSe/(Cd,Mg)Se quantum well. Our work establishes the so far unsettled relation between lasing regimes that differ by their light-matter coupling strength and degree of electron–hole Coulomb correlation. Semiconductor microcavities coupled to a quantum well can produce three regimes of coherent light generation depending on the nature of the light–matter and electron–hole interactions. The authors design a Se/Te based microcavity containing a single quantum well which enables them to achieve all three lasing regimes in the one device.

Epithelial cell adhesion molecule (EpCAM), which is expressed in the majority of epithelial tissues, exhibits tumor growth promoting abilities and is overexpressed in human epithelial ovarian cancer. Therefore, EpCAM is considered to be a promising target for specific immune‑based therapies. The present study evaluated the role of IL‑6 and IL‑8 in the expression of EpCAM in the A2780 human ovarian cancer cell line. Furthermore, the cellular localization of the EpCAM protein in A2780 cells was determined and the effect of EpCAM inhibition on the proliferation of the A2780 cells was investigated. An MTT assay demonstrated that blocking EpCAM with anti‑EPCAM antibodies had no effect on cellular metabolic activity (proliferation). Gene expression analysis revealed that IL‑8 increased EpCAM expression, whereas IL‑6 and the combination of IL‑6/IL‑8 had no effect on EpCAM expression. Immunofluorescence analysis confirmed that EpCAM is expressed on A2780 cell membranes. The present results demonstrated that IL‑8 increased EpCAM expression at the mRNA level in ovarian cancer cells and suggested a potential role of IL‑6 as an inhibitor of IL‑8‑stimulated EpCAM expression.

Skin acts as a mechanical barrier between human body and environment. Epidermal cells are regularly exposed to many physiological and environmental stressors, such as pesticides, like chlorpyrifos (CPS). It is recognised that CPS may affect metabolism of other exo- and endogenous substances by affecting enzyme activity and expression. This study aims to investigate the effect of CPS on expression of CYP27A1, CYP27B1 and CYP24A1, the enzymes involved in synthesis and metabolism of vitamin D3, in human keratinocytes HaCaT and human fibroblasts BJ. Synthesis of vitamin D3 in cells was initiated by irradiating with UVB. Expression of CYP27A1, CYP27B1 and CYP24A1 was evaluated by RT-qPCR and Western blot. Our experiments revealed that expression of all tested cytochrome P450 isoforms in cells exposed to CPS changed significantly. Exposure of HaCaT keratinocytes to CPS decreased CYP27A1 mRNA levels, but increased CYP27B1 and CYP24A1 mRNA levels. This was confirmed at the protein level, except for the CYP27A1 expression. Outcome for the BJ cells was however less conclusive. Though exposure to CPS decreased CYP27A1 and CYP27B1 mRNA levels, at protein level increasing concentration of CPS and UVB intensity induced expression of CYP27A1 and CYP24A1. The expression of CYP27B1 isoform decreased in line with mRNA level. Nevertheless, it can be concluded that CPS may therefore interrupt vitamin D3 metabolism in skin cells, but further studies are required to better understand such mechanisms.