Depuis deux ans environ, nous subissons l'effet de la pandémie liée au SARS-COV-2 .Désemparés, les politiques dans leurs discours sont passés du thème d'une grippe ordinaire, sans effets majeurs, à des obligations de prévention plus crédibles, parfois avec du retard.La France comptabilise aujourd'hui plus de 130000 morts !Toute la société (dont des scientifiques), dans le flou ambiant, a ajouté sa vision et ses propres propositions, ce qui n'a rien arrangé.En utilisant (pour l'essentiel) des méthodes de résolution d'équations différentielles classiques, on retrouve la plupart des couplages entre virus (croissance, exposition, disparition) et individus (malades, immunisés, etc.), déjà validés scientifiquement.Des tendances issues de cette modélisation semiquantitative valident nombre d'effets : distanciation sociale, gestes barrières, qualité du masque, intérêt du télétravail, etc. En revanche, malgré le discours du politique, validé par son conseil scientifique, il est possible que la vaccination ne serve pas à réduire la pandémie si les vaccinés (protégés des effets les plus graves) réémettent du virus, même en petites quantités.De même, l'existence d'une immunité collective n'est pas prouvée... ABSTRACT.For about two years, we have been suffering from the effect of the SARS-COV-2 pandemic .Distraught, politicians in their speeches have gone from the theme of an ordinary flu, without major effects, to more credible prevention obligations, sometimes with delay.France counts today more than 130,000 deaths!All the society (including scientists), in the ambient vagueness, added its vision and its own proposals, which did not arrange anything.By using (for the most part) methods of solving classical differential equations, we find most of the couplings between viruses (growth, exposure, disappearance) and individuals (sick, immunized, etc.), already scientifically validated.Trends resulting from this semi-quantitative modeling validate a number of effects: social distancing, barrier gestures, mask efficiency, interest in teleworking, etc.On the other hand, in spite of the political rhetoric, validated by its scientific council, it is possible that vaccination will not serve to reduce the pandemic if the vaccinated (protected from the most serious effects) re-emit the virus, even in small quantities.Similarly, the existence of a collective immunity is not proven...

Le bio-printing issu des technologies de fabrication additive se développe en termes de recherches scientifiques parce qu'avec cette technologie récente il y aurait possibilité, avec des cellules souches des personnes atteintes de maladies graves, de recréer un jour des organes déficients sans qu'existent des rejets de la part des patients malades puisque ces organes seraient recréés à partir de cellules saines compatibles.Ce que l'on observe c'est une augmentation quasi-exponentielle du volume des publications expérimentales alors que la modélisation des processus de croissance et de différenciation cellulaire reste peu explorée.Pour autant, le bio-printing nécessite la convergence de nombreuses disciplines scientifiques, ce qui impose une réflexion épistémologique visant la fabrication robuste d'organes.Faute de la possibilité de rencontre entre spécialistes scientifiques concernés, la modélisation mathématique permet de tenter de trouver de possibles chemins existant entre extraction de cellules saines d'un patient et réalisation potentielle d'un tissu, voire d'un organe.Le but de ce travail est d'illustrer cette potentialité permettant de savoir quelles questions poser aux biologistes pour avancer sur ce sujet (en particulier), mais également de connaître les limites de ce type d'exercice.ABSTRACT.Bio-printing from additive manufacturing technologies is developing in terms of scientific research because with this recent technology it would be possible, with stem cells from people with serious diseases, to one day recreate deficient organs without rejection from sick patients since these organs would be recreated from compatible healthy cells.What is observed is an almost exponential increase in the volume of experimental publications, while the modelling of cell growth and differentiation processes remains little explored.Nevertheless, bioprinting requires the convergence of many scientific disciplines, which imposes an epistemological reflection aimed at robust organ production.In the absence of the possibility of a deep association between the scientific specialists concerned, mathematical modelling makes it possible to attempt to find possible paths existing between the extraction of healthy cells from a patient and the potential production of a tissue, or even an organ.The aim of this work is to illustrate this potentiality, making it possible to know what questions to ask biologists in order to make progress on this subject (in particular), but also to know the limits of this type of exercise.MOTS-CLÉS.

Photodynamic therapy is a therapeutic option to treat cancer and other diseases. PDT is used every day in dermatology, and recent developments in the treatment of glioblastoma, mesothelioma or prostate have demonstrated the efficacy of this modality. In order to improve the efficacy of PDT, different strategies are under development, such as the use of targeted PS or nanoparticles to improve selectivity and the design of light devices to better monitor the light dose. Due to the low penetration of light into tissue, another way to improve the efficacy of PDT to treat deep tumors is the use of upconversion NPs or bi-photon absorption compounds. These compounds can be excited in the red part of the spectrum. A relatively new approach, which we will call PDTX, is the use of X-rays instead of UV-visible light for deeper penetration into tissue. The principle of this technique will be described, and the state-of-art literature concerning this modality will be discussed. First, we will focus on various photosensitizers that have been used in combination with X-ray irradiation. To improve the efficacy of this modality, nanoparticles have been designed that allow the conversion of high-energy ionizing radiation into UV-visible light; these are potential candidates for the PDTX approach. They will be discussed at the end of this review.

The eco-friendly cooperative Cu/Pd-catalyzed oxidative Heck reaction of allyl alcohols with heteroaryl boronic acids under air was described. The ready availability of starting materials and the mild reaction conditions made this protocol a safe and operationally convenient strategy for the efficient synthesis of β-heteroaryl carbonyl compounds.

BACKGROUND:The occupational exposure to urban pollution may induce adverse effects on the human health. METHODS:Plasma levels of thyrotropin stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) of 50 outdoor workers and 50 indoor workers were compared. RESULTS:In the outdoor workers the TSH levels were significantly higher than in the control subjects (p =0.02) while the average of FT3 and FT4 values, was not significantly different compared to the controls (p > 0.05). CONCLUSIONS:The differences found for TSH levels between outdoor and indoor workers, though not high, suggest that, due to greater exposure to environmental pollutants, the outdoor workers are more susceptible to the development of function abnormalities of the thyroid gland compared to indoor workers.

Formaldehyde is toxic to humans and is classed as a category 1 carcinogen. Methods have been developed to degrade this compound, but for industrial application, relevant mathematical models are required. This study models a fixed bed photocatalytic reactor designed to degrade formaldehyde constituted of TiO2-coated Raschig rings illuminated by UV-A lamps. Initially, the reactor’s hydraulic behavior was described based on an experimental residence time distribution. This model takes into account hydraulics, light distribution, chemical kinetics and mass transfer in the reactor. The dispersion model satisfactorily represented the reactor’s hydraulic behavior. This model, combined with a Langmuir–Hinshelwood kinetic model, was then used to calculate variations in concentration at the reactor output. By adding the transfer flux between the bulk and the surface to the material balance equation, it is possible to distinguish between mass transfer and chemical reaction limitation and determine the chemical kinetics. Experimental data from different initial concentrations were used to calculate the Langmuir–Hinshelwood kinetic constants. The dispersion model with chemical reaction was validated under various irradiation and flow rate conditions. The results show that the fixed bed photocatalytic reactor efficiently degrades formaldehyde in an aqueous solution. The chemical constants of photocatalytic degradation obtained for formaldehyde are necessary parameters if this technology is to become the basis of industrial applications. This study provides a new tool, integrating mass transfer limitations and light distribution, to design photo-reactors.

The aim of this study was to evaluate the usefulness and specificity of urinary 1-hydroxypyrene (1-OHPu) as a biomarker of the exposure from urban pollution to polycyclic aromatic hydrocarbons (PAHs) among outdoor workers in a meta-analysis. Our meta-analysis was performed according to standard methods, and the results show that the concentrations of 1-OHPu tend to be higher in exposed workers than in unexposed workers (if we exclude two highly heterogeneous articles), in exposed non-smokers than in unexposed non-smokers and in exposed than in unexposed workers who were carriers of the CYP1A1 genotype and in those with the glutathione- S -transferase M1 (−)genotype. These genotypes enhance the effect of exposure, particularly in non-smokers. Smoking reduces the differences between exposed and unexposed subjects. In conclusion, our results suggest that the use of the 1-OHPu biomarker appears to be reliable for studying occupational exposure to PAHs from urban pollution, as long as environmental and behavioural factors are considered.

In water, chlorine reacts with nitrogen-containing compounds to produce disinfection byproducts such as nitrogen trichloride which induces ocular and respiratory irritations in swimming pool workers. A technical solution has been used to reduce NCl3 exposure to acceptable levels, by adding a stripping step to the water recycling loop. The pollutants extracted are currently rejected into the atmosphere without treatment. However, the physical properties of NCl3 could be harnessed to induce its controlled degradation by direct or indirect light. This paper describes the way to transform NCl3 into oxidizing chlorine by photocatalysis under laboratory conditions. Photocatalytic oxidation efficiently degrades gaseous nitrogen trichloride, producing compounds such as HClO. About 60% of NCl3 decomposed was converted into HClO which could be used as a disinfection compound. A kinetic model is proposed for the photocatalytic process based on a convection/diffusion model. The Langmuir-Hinshelwood model was applied to the chemical part of the mechanism. The apparent quantum yield was also estimated to assess the optimal irradiance for NCl3 transformation. The results show that photocatalysis performs much better than photolysis alone for NCl3 removal, i.e. at least 25 times more efficient.

OBJECTIVES:This is the first research study to compare among female, non-smoker workers: (a) the exposure to benzene, toluene and xylenes (BTXs) in urban air during work in the street (traffic policewomen, TP) vs. work in vehicles (police drivers, PD); (b) the exposure to BTXs in urban environments (in street and in car) vs. rural environments (roadwomen, RW); (c) the values of blood benzene, urinary trans, trans muconic acid (t,t-MA) and urinary S-phenylmercapturic acid (S-PMA) in urban areas (in street and in car) vs. rural areas.METHODS:Passive personal samplings and data acquired using fixed monitoring stations located in different areas of the city were used to measure environmental and occupational exposure to BTXs during the work shift in 48 TP, 21 PD and 22 RW. In the same study subjects, blood benzene, t,t-MA and S-PMA were measured at the end of each work shift.RESULTS:Personal exposure of urban workers to benzene seemed to be higher than the exposure measured by the fixed monitoring stations. Personal exposure to benzene and toluene was (a) similar among TP and PD and (b) higher among urban workers compared to rural workers. Personal exposure to xylenes was (a) higher in TP than in PD and (b) higher among urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA levels were similar among TP and PD, although the blood benzene level was significantly higher in urban workers compared to rural workers. In urban workers, airborne benzene and blood benzene levels were significantly correlated.CONCLUSIONS:Benzene is a human carcinogen, and BTXs are potential reproductive toxins at low dose exposures. Biological and environmental monitoring to assess exposure to BTXs represents a preliminary and necessary tool for the implementation of preventive measures for female subjects working in outdoor environments.

Angiogenesis is a key step in the tumoral progression process. It is characterized by an over-expression of a number of matrix metalloproteinases (MMP). Among these MMPs, gelatinases (MMP-2 and MMP-9) are known to play a critical role in tumor angiogenesis and the growth of many cancers. Photodynamic Molecular Beacons (PMB) can be designed for cancer treatment by associating a chlorin-like photosensitizer and a black hole quencher linked by a gelatinase substrate peptide with the aim of silencing photosensitizer toxicity in non-targeted cells and restore its toxicity only in surrounding gelatinases. This article provides a report on the synthesis and photophysical and biochemical studies of new families of PMB, using tetraphenylchlorin and a black hole quencher as a donor-acceptor pair, and MMP specific sequence (H-Gly-Pro-Leu-Gly-Ile-Ala-Gly-Gln-Lys-OH or H-Pro-Leu-Gly-Leu-OH) to keep them in close proximity. Different spacers were used to evaluate the influence of the distance between the photosensitizer and the quencher on the photophysical properties and enzymatic activation of the PMB. Time-resolved quenching experiments were performed and FRET energy transfer could be observed. Photosensitizers' triplet state band in transient absorption disappears in PMB. However, even if both MMP-2 and MMP-9 were found to efficiently cleave the peptide alone, no cleavage was observed for all PMB. Further studies would be required to assess the ability of the PMB constructs to retain the sensitivity of the peptide linker to be cleaved by matrix metalloproteinases.

Air pollution represents a health risk for people living in urban environment. Urban air consists in a complex mixture of chemicals and carcinogens and its effects on health can be summarized in acute respiratory effects, neoplastic nonneoplastic (e.g. chronic bronchitis) chronic respiratory effects, and effects on other organs and systems. Air pollution may be defined according to origin of the phenomena that determine it: natural causes (natural fumes, decomposition, volcanic ash) or anthropogenic causes which are the result of human activities (industrial and civil emissions). Transport is the sector that more than others contributes to the deterioration of air quality in cities. In this context, in recent years, governments of the territory were asked to advance policies aimed at solving problems related to pollution. In consideration of the many effects on health caused by pollution it becomes necessary to know the risks from exposure to various environmental pollutants and to limit and control their effects. Many are the categories of "outdoor" workers, who daily serve the in urban environment: police, drivers, newsagents, etc.

BACKGROUND:Purpose of this study is to evaluate and to compare the excretion of urinary 1-hydroxypyrene (1-OHPu) in traffic policemen (TP) and drivers (D) of a large Italian city and to evaluate the existence and the degree of correlation between airborne exposure to 15 different polycyclic aromatic hydrocarbons (PAHs) and 1-OHPu levels in the examined population.METHODS:192 male workers, 115 TP and 77 D, were monitored for 1-HOPu. A subgroup of non-smoking workers (subgroup B: 59 TP and 15 D) was also examined and 15 environmental PAHs was monitored through the personal samplings for the measurement of the particulate phase.RESULTS:The 1-OHPu levels and the values of personal airborne exposure to PAHs were significantly higher among non-smoking TP than among non-smoking D (p < 0.05). In subgroup B the levels of environmental exposure to all the 15 PAHs measured in TP and only 6 of 15 PAHs measured in D were significantly correlated with the values of 1-OHPu (p < 0.05).CONCLUSIONS:Our results suggest that the use of 1-OHPu as an indicator of exposure to PAHs is reliable also for what concerns the study of the low-dose work-related exposure in urban outdoor workers.

Context: Arsenic is a ubiquitous element present in urban air as a pollutant, and it may interfere with thyroid hormones. Objective: To evaluate the association between the personal exposure to arsenic and levels of TSH, fT4, fT3, and Tg in urban and rural workers. Materials and methods: Total urinary arsenic and thyroid markers were obtained from 108 non-smoking traffic policemen and 77 subjects working as roadmen in a rural area. Fifty subjects were monitored to evaluate airborne exposure to arsenic. Results: The mean value of exposure to arsenic was 2.9 µg/m3 in traffic policemen, while the mean value was less than 0.1 µg/m3 in roadmen. The mean values of urinary arsenic (10.4 μg/g creatinine vs. 5.2 μg/g creatinine; p = 0.000), TSH (1.6 µlU/ml vs. 1.3 µlU/ml; p = 0.006), fT3 (3.5 pg/ml vs. 3.7 pg/ml; p = 0.000), fT4 (1.2 ng/dl vs. 1.3 ng/dl; p = 0.000) and Tg (42.8 ng/ml vs. 36.1 ng/ml; p = 0.04) were significantly different between traffic policemen and roadmen. In traffic policemen, urinary arsenic and arsenic in the air were correlated to the airborne arsenic and TSH values, respectively. Urinary arsenic was correlated to TSH, Tg, fT3, and fT4 values. The multiple linear regression models showed the following associations: i) among urinary arsenic, arsenic in the air and job title; ii) among TSH, fT3, Tg and urinary arsenic; and iii) between fT4 and both urinary arsenic and alcohol intake. Conclusion: These results provide information about the relationship between exposure to arsenic and thyroid markers and may be useful for other categories of outdoor workers who are similarly exposed.

Since decades, the connection between scientific concepts and industrial applications is promoted in any scientific domains. However, for several reasons, it is possible to observe that temporal delays (decades) are needed before effective industrial applications. This is the case for photocatalysis. In the 1980's, this promising methodology was considered by Industry as an eminent technology for organic pollutant abatement in air or / and in water. Now, after more than 30 years of research, several applications have been developed. But, at present, the stabilization of all these technologies is not yet completely reached. In this respect, on account of its properties, light is a reagent with numerous advantages for producing chemical substances or, conversely, for destroying organic pollutants. However, a certain contraction in industrial developments is increasingly being observed in both domains. The aim of this discussion paper, is to attempt to understand how satisfying the needs of society is so weakly linked to the scientific knowledge emanating from the work of photochemists and photophysicists despite the undeniable success in certain applicative niche markets. Several reasons defined in this paper illustrate to a great extent, the need for an interdisciplinary approach coupled with imagination and in-depth science which must contribute to promoting application-related knowledge.

L'étude théorique de la co-oxydation de deux substances oxydables RH et R'H est effectuée systématiquement à partir d'un schéma cinétique général et en envisageant successivement les différents cas possibles. Dans cette étude, on admet que RH s'oxyde, en l'absence de R'H, selon un mécanisme radicalaire en chaînes longues, alors que R'H peut, en l'absence de RH, s'oxyder selon un mécanisme radicalaire en chaînes longues, courtes ou par stades. A partir de cette étude systématique, on propose des techniques simples qui permettent de comparer des résultats expérimentaux et le mécanisme proposé. Les conclusions déduites de ce dernier sont confrontées aux résultats expérimentaux de la co-oxydation du cumène et-de la décaline. The theoretical study of the cooxidation of two oxidizable compounds, RH and R'H, is systematically carried out by using a general kinetic scheme and considering the different possible cases. In this study, it is assumed that the oxidation of RH in the absence of R'H takes place according ta a long-chain radical mechanism, whereas the oxidation of R'H in the absence of RH takes place according ta a radical mechanism by long chains, short chains or by steps. Based on this systematic study, some simple techniques are put forward for comparing experimental results and the proposed mechanism. The conclusions deduced from the latter are compared with the experimental results from the cooxidation of cumere and decalin.

These last past years, nitrate ions have been in vogue pollutants because often incriminated in aquatic pollutions. Very currently used as chemical fertilizers, nitrate can be transformed, when ingested, into carcinogenic nitrosamines in the human body. So it is necessary to monitor the concentrations of these anions, even as traces, particularly in drinking waters or in order to prevent pollution accidents in environmental waters. We recall that the recommanded nitrate concentration by the European Community for drinking water is less than 50 mg NO3 ‐ L ‐1 .