Academic literature on the topic 'Interaction UVX solide'

Polyphenols are a large diversity of chemical types and interactions that can be responsible for a multiplicity of protective functions ranging from toxicity and light/UV shielding to signal transduction. Bacharis antioquensis has been described as a potential source of new photoprotective compounds with antioxidant capacity associated to polyphenols compounds. The aim of the present work was to develop a micropropagation protocol of B. antioquensis and evaluate the production of polyphenols by in vitro plants exposure to UVB radiation. Branches in juvenile stage of B. antioquensis were collected, desinfected and cultured on half strength Murashige and Skoog medium, supplemented or not with growth regulators (TDZ, BA or GA3) on light/darkness conditions and liquid/solid media. After UV treatments, the absorption coefficient in the UVA-UVB range, the antioxidant capacity and the total phenol content (TPC) from all tissue cultures and the wild tissue were evaluated. Growth regulators, light conditions and type of culture medium (solid or liquid) had a favorable effect on the response of explants. Treatments containing BA + GA3 regulators (2 and 0.5 mg/L respectively) and TDZ (0.5 mg/L) showed positive results in bud growth in liquid medium and darkness. Results showed that UVR exhibited promoting effects on the accumulation of polyphenols, enhancing the absorption coefficient in the UVA-UVB range, the antiradical capacity and the TPC of B. antioquensis in vitro plants. Rev. Biol. Trop. 66(2): 754-764. Epub 2018 June 01.

Abstract BACKGROUND: Graft versus host disease (GVHD) is a significant contributor to non-relapse mortality after allogeneic stem cell transplant (SCT). Steroids are first line therapy and extracorporeal photopheresis (ECP) is used as second line therapy for steroid refractory or intolerant patients. ECP has immunomodulatory effects rather than immunosuppressive effect which decreases the risk of infection, and may decreases the risk of disease relapse. There are two ECP instruments approved in the US for the treatment of Cutaneous T Cell Lymphoma (CTLC), however both have been used "off-label" to prevent or treat solid organ transplant rejection, acute and chronic GVHD, and other autoimmune diseases. Until recently the UVAR-XTS instrument has been the most commonly used closed system in the US until the CELLEX was approved in 2009. The CELLEX and the UVAR-XTS procedures are similar in that buffy coat is collected, exposed to methoxsalen (UVADEX®) ex vivo and then UVA light before returning the treated cells back to the patient in a closed looped system. The instruments differ in the collection of the buffy coat; collection is continuous by the CELLEX, and it is intermittent by UVAR-XTS. In addition CELLEX has been shown to be more efficient in collecting mononuclear cells when compared to the UVAR -XTS. Little clinical data is available comparing the clinical efficacy of the two instruments in the setting of GVHD. We designed a single institution retrospective study to compare the efficacy and safety of the two instruments. The primary outcomes analyzed were >/=50% reduction of steroid dose between the initial and final dose during the study period, and the number and type of adverse events that occurred during the ECP procedures. METHODS: Study Population: We reviewed charts of allogeneic stem cell transplant patients who received ECP for the treatment of acute or chronic GVHD between 1/2009 and 12/2015. The patients were divided into two groups based on the type of ECP instrument that was used. One group was exclusively treated with UVAR-XTS while the second group with CELLEX. Patients who received treatments with both instruments were excluded. The frequency of steroid dose reduction by >/=50%, and toxicity was compared between the two instruments while adjusting for age, gender, GVHD severity, number of organs involved by GVHD, type of allogeneic stem cell transplant, conditioning regimen, number of other immunosuppressants, type of anticoagulants (ACDA vs heparin), type of access line, and baseline blood counts. Statistical Analysis: The baseline characteristics of the patients in the two groups were compared using Chi square, Fischer's exact test for categorical variables and one-way analysis of variance (ANOVA) for continuous variables. Chi square analysis was used to determine the difference in frequency of >/=50% steroid dose reduction and adverse events between the two groups. Logistic multivariate regression was used to evaluate the potential interactions of all significant covariates. A p value of less than 0.05 was considered to be statistically significant. Statistical analyses were performed using STATA14 software (StataCorp, College Station, TX). RESULTS: We identified 242 allogeneic SCT recipients who received ECP for acute or chronic GVHD in the study period, 146 of whom met the selection criteria. 69 patients had all procedure performed with UVAR-XTS and 77 patients had all procedures performed with CELLEX. There was no significant difference in age, gender, percent of acute GVHD, anticoagulant used, type of transplant, number of organs involved, number of immunosuppressants, vascular access and baseline blood counts between the two treatment cohorts as shown in table 1. Although year of transplant and conditioning regimen were different between the two cohorts, neither of these covariates influenced the impact of instrument on the primary outcome. In multivariate analysis, the patients who underwent ECP with CELLEX were 3 times more likely to have >/=50% steroid dose reduction (p =0.01). The total number of adverse events was similar between the instruments (p = 0.73). (Table 2) CONCLUSION: More than twice as many patients with GVHD treated with the CELLEX had a steroid dose reduction by >/=50% reflecting clinical improvement when compared to the patients treated with the UVAR-XTS. Similar safety profile was observed between the two instruments based on a similar number of adverse events. Disclosures No relevant conflicts of interest to declare.

L’objectif de cette thèse est de développer un concept inédit permettant l’utilisation de silices mésoporeuses pour encapsuler des principes actifs cosmétiques de façon permanente, ce qui permet d’améliorer leur tolérance cutanée, d’optimiser leur stabilité à la lumière tout en préservant leur efficacité et de faciliter leur formulation au sein de produits cosmétiques. Pour cela, la voie consistant à encapsuler des filtres UV à usage cosmétique au sein de silices mésoporeuses de type MCM-41 de façon in-situ a été choisie car elle semblait la plus propice à l’encapsulation d’une grande quantité de principes actifs de façon permanente. Deux filtres UV ont été étudiés un lipophile, nommé Parsol MCX, et un hydrophile, appelé Parsol HS. Pour l’ensemble des principes actifs étudiés, un taux d’encapsulation approprié a été obtenu et les caractérisations, effectuées notamment par RMN du solide, ont permis de montrer que l’encapsulation est effective au sein des pores ce qui, couplé à la bonne stabilité de l’encapsulation dans le cas de l’actifs hydrophile, garantit un contact minimum entre l’actif et la peau du consommateur. En revanche, un relargage important de filtre UV lipophile a été constaté. Il a été établi que les propriétés physico-chimiques des matériaux diffèrent significativement suivant que les principes actifs encapsulés soient lipophiles ou hydrophiles. Dans tous les cas, l’organisation poreuse, l’ordre structural et la morphologie des particules contenant des principes actifs varient significativement par rapport aux silices mésoporeuses de référence de type MCM-41, synthétisées sans principe actif. La présence de principe actif au sein du milieu réactionnel a donc une influence sur la structure et la texture des matériaux obtenus, ce qui est dû aux interactions entre les molécules de principe actif, les espèces silicate et les molécules de tensioactif au sein du milieu réactionnel
The objective of this thesis is to develop a new concept that consists to permanently encapsulate cosmetic active ingredients into mesoporous silica. The encapsulation of these active molecules improves their skin tolerance, optimizes their light stability while preserving their effectiveness and facilitates their formulation in cosmetic products. Thus, UV filters have been encapsulated in MCM-41 type mesoporous silica by using in-situ route because it seemed the most efficient route to achieve permanently encapsulation of large quantities of active. Two UV filters have been studied. One is lipophilic (Parsol MCX) and the other is a hydrophilic (Parsol HS). For all the active molecules studied, an appropriate encapsulation rate was obtained and the characterizations, particularly these performed by solid-state NMR, have shown that the encapsulation is effective within the pores which, coupled with the good stability of encapsulation in the case of hydrophilic actives, ensures minimal contact between the active and the consumer's skin. In contrast, a significant release of lipophilic UV filter was found. It was established that the physico-chemical properties of the synthesized materials differ significantly according to the lipophilic or hydrophilic nature of the encapsulated molecules. In all cases, the porous organization, the structural order and the morphology of the particles containing active ingredients vary significantly compared to the reference MCM-41 type mesoporous silica, synthesized without active ingredient. Thus, the presence of the active ingredient in the reaction medium has an influence on the structure and the texture of the synthesized materials, which is due to interactions between the actives molecules, the silicate species and the surfactant molecules in the reaction medium

Nous avons etudie la cinetique des radicaux cf et cf#2 dans un plasma pulse de cf#4 utilise pour la gravure de couches minces de si ou sio#2 dans l'industrie micro-electronique. Les profils de concentration spatiaux resolus dans le temps de ces especes ont ete determines par la technique de fluorescence induite par laser. Ils permettent d'etudier les mecanismes de perte et de production de ces radicaux en phase gazeuse et sur les surfaces du reacteur. Un nouveau mecanisme de production en surface de cf et de cf#2 a ainsi ete mis en evidence, en particulier sur un substrat de silicium. Nous avons alors developpe des techniques pour comparer les flux absolus des neutres cf#x produit au flux d'ions incident. La concentration de cf#2 a ete determinee par la technique d'absorption uv, alors que pour celle de cf, nous avons developpe une nouvelle theorie permettant de rendre la f. I. L. Quantitative en prenant en compte les effets de saturation partielle de l'absorption. Enfin, pour mesurer le flux ionique en milieu polymerisant, nous avons mis au point un nouveau type de sonde electrostatique capable de fonctionner dans les chimies fluorocarbonees qui deposent rapidement un film isolant sur la surface de la sonde. Les resultats quantitatifs obtenus nous ont permis de montrer que le mecanisme de production de cf est la neutralisation et fragmentation des ions incidents. Dans le cas de cf#2, un deuxieme mecanisme lie a la decomposition d'un couche de polymere domine lorsque la concentration de fluor est faible. Cette couche (responsable de la selectivite de la gravure) est formee a partir de neutres lourds c#xf#y eux meme formes par un mecanisme de polymerisation en phase gazeuse (par des reactions c#xf#y+cf#2).

Gegenstand der vorliegenden Arbeit ist die UV/Vis-spektroskopische Bestimmung der Kamlet-Taft-Polaritätsparameter von strukturell unterschiedlichen Ionischen Flüssigkeiten (ILs), mit Hilfe von spezifischen solvatochromen Sondenmolekülen. Dabei wurden der Einfluss des Anions und Kations auf die Polarität, sowie die Stärke der Wechselwirkung zwischen beiden Ionen untersucht. Es konnte für Ionischen Flüssigkeiten mit dem 1-Butyl-3-methylimidazoliumkation eine 1H-NMR-spektroskopische Methode zur Ermittlung der Polaritätsparameter entwickelt werden. Diese bietet den Vorteil, dass sie auch bei farbigen, hydrolyseempfindlichen oder höher schmelzenden ILs eingesetzt werden kann, wenn die Anwendung solvatochromer Sondenmoleküle nicht möglich ist. Ein weiteres Augenmerk lag auf der Untersuchung der Wechselwirkung zwischen den ILs und silikatischen Oberflächen. Neben der Studie der anionenvermittelten starken Physisorption von 1-Methylimidazoliumchlorid an Aerosil®300 konnte auch eine neuartige Methode zur gezielten Chemisorption von Imidazolium- und Phosphoniumkationen an Siliziumdioxidoberflächen entwickelt werden. Dabei wurden verschieden Carbene und Ylide als basische IL-typische Kationenprecursoren eingesetzt. Die Analyse der erhaltenen Materialien erfolgte mit Hilfe verschiedener Methoden der Festkörper-NMR-Spektroskopie.

Spectroscopy involves the study of the interactions of electromagnetic radiation with matter. In the case of liquids, radiation of a wide range of frequencies, and thus energies, has been used, all the way from radio-frequency waves to X-rays. Experiments involving neutrons, which are associated with very short wavelengths, are also important. In the spectroscopic experiment the incident radiation may be either absorbed or scattered and the experimental information is obtained by examining the intensity and direction of the radiation after it has passed through the sample. Several spectroscopic techniques will be considered in this chapter. X-ray and neutron diffraction techniques are powerful tools for studying the structure of liquids and have been introduced in chapter 2. They may also be used to study the structure of solutions and determine distribution functions for both the solute and solvent. The feasibility of these experiments depends on the number of different nuclei involved in the system. UV-visible spectroscopy is mainly used to study electronic transitions in polyatomic species. These species are often complex ions formed between the electrolyte and the solvent, or between the cation and one or more anions. Vibrational spectroscopy involves electromagnetic radiation of lower energy, usually in the infrared region. It is used to study intramolecular vibrational modes and how they are altered by the environment in solution. It can also be used to study the bonds formed between solute and solvent in the solvation process. Finally, nuclear magnetic resonance spectroscopy and its application to the study of solvation will be discussed. This is a particularly powerful technique because it provides information about the environment of a given nucleus, and experiments specific to a given nucleus can be carried out provided the nucleus has a non-zero magnetic moment. Several other spectroscopic techniques are commonly used [G1] but those considered here provide a representative picture of what can be learnt from those experiments. One should remember that the atoms and molecules in liquids are not motionless but in a state of flux determined by the intermolecular interactions and temperature. From the study of microwave spectroscopy discussed in chapter 4, it was found that rotational diffusion processes in liquids are characterized by relaxation times the order of a few picoseconds.

In the field of tissue engineering, scaffold is the foundation structure that provides the desired mechanical support for the tissue being engineered, surface for cells to attach and spread, and access for nutrient transport crucial for cell viability. The scaffolds are 3D building blocks which are designed and fabricated precisely prior to its implantation to the host tissue. When scaffolds with desired shape and size are fabricated, they can be seeded with cells and appropriate growth factors. After cells show healthy growth within the scaffold, they are implanted into the body with the scaffold to allow full-scale tissue regeneration. In this research, photolithography is adapted as a fabrication method to generate PEGDA-based structures. In this method, ultra-violet (UV) light is reflected on PEGDA and as a result of the interaction between UV light and precursor solution, PEGDA turns into solid form. Despite the potential of PEGDA in scaffold applications, the mechanical properties have not been studied in a great extent. Therefore, in this project, the mechanical characterization of PEGDA was conducted for various polymer concentrations. Specimens with 20%, 40%, 60%, 80% and 100% PEGDA to water ratio were prepared for compression tests. Our preliminary experimental data results show that, mechanical properties of PEGDA can be controlled by changing the PEGDA to water ratio. Stronger and stiffer structures can be obtained with high PEGDA concentrations while softer structures can be fabricated with reduced PEGDA concentrations.

Abstract Polymer jet printing (PJP) is a direct-write additive manufacturing process, emerging as a rapid high-resolution method particularly in the medical field for the fabrication of a wide spectrum of products, e.g., anatomical models, tissue scaffolds, implants, and prosthetics. PJP allows for non-contact multi-material deposition of functional polymer inks. The PJP process centers on simultaneous deposition of build and support photopolymer materials on a free surface, which are immediately cured in situ using a UV light source, allowing for solid-freeform fabrication. The PJP process is inherently complex, governed by a multitude of parameters as well as material-machine-process interactions, which collectively affect the functional properties of a fabricated structure. Consequently, physics-based characterization and optimization of the PJP process would be inevitable. In this study, a new test standard was forwarded for the characterization of the mechanical properties of PJP-fabricated bone structures; the standard was designed on the basis of an X-ray p-CT scan of a femur bone in addition to the ASTM D638-14 standard. Furthermore, the Taguchi L8 orthogonal array design was utilized to investigate the effects of influential PJP process parameters on the mechanical properties of the bone structures, including Young’s modulus of elasticity, tensile strength, breaking strength, and ductility. The selected process parameters (each at two levels) were: (i) print direction, (ii) resolution factor, (iii) UV light intensity, and (iv) deposition head temperature. The mechanical properties of the femur bone structures were measured using a tensile testing machine. The UV light intensity appeared as the most significant factor, influencing all the aforementioned mechanical properties, while the resolution factor was identified as an inconsequential factor. In addition, it was observed that the print direction and the head temperature significantly affected the breaking strength and the ductility, respectively. Overall, the results of this study pave the way for further investigation of the effects of the PJP parameters toward optimal fabrication of complex bone tissue scaffolds and implants with long-lasting functional characteristics.

Marbofloxacin (MRB) is a fluoroquinolone used as a veterinary antibiotic. Some analytical methods of optical absorption are used for their determination in pharmaceutical formulations. Thus, we decided to study the electronic absorption spectrum of MRB in the UV-Vis region. For this, we use the TD-DFT, COSMO methods - based on the solvation continuum model - and micro-hydration. The interactions of MRB in both water and vacuum were simulated using computational modeling techniques. Ab initio quantum calculations were used to optimize the geometry of the isolated molecule and in the optical transition energy calculations. The solute-solvent simulation was performed with the Molecular Dynamics technique in the NpT ensemble using a temperature of 300 K in the Amber computer package. The system balance was monitored by Root Mean Square Deviation. The analyzes of the absorption spectra were carried out using the micro-hydration method. This method involved the use of different numbers, from 2 to 8, of the water molecules of the first solvation layer to calculate transition energies. The transition energies were calculated using the TD-DFT method at the theory level B3LYP / 6-311G using together the Conductor-like Screening Model solvation model that assesses the effect of the solvent implicit in the system. For all micro-hydration systems, energy absorption decreases as the wavelength increases. Observing the values it is noticed that there was a deviation in the absorption spectrum 325.4 nm (in the isolated molecule) to 274.1 (with the addition of water). These values are within the experimental ones where we have the bands with maximum absorption at 268 nm and 335 nm.