Spiropyrans undergo Cspiro–O bond breaking to their ring-open protonated E-merocyanine form upon protonation and irradiation via an intermediate protonated Z-merocyanine isomer. We show that the ...extent of acid-induced ring opening is controlled by matching both the concentration and strength of the acid used and with strong acids full ring opening to the Z-merocyanine isomer occurs spontaneously allowing its characterization by 1H NMR spectroscopy as well as UV/vis spectroscopy, and reversible switching between Z/E-isomerization by irradiation with UV and visible light. Under sufficiently acidic conditions, both E- and Z-isomers are thermally stable. Judicious choice of acid such that its pK a lies between that of the E- and Z-merocyanine forms enables thermally stable switching between spiropyran and E-merocyanine forms and hence pH gating between thermally irreversible and reversible photochromic switching.
The synthesis of a series of (formazanate)boron difluorides and their 1-electron reduction products is described. The neutral compounds are fluorescent with large Stokes shifts. DFT calculations ...suggest that a large structural reorganization accompanies photoexictation and accounts for the large Stokes shift. Reduction of the neutral boron difluorides occurs at the ligand and generates the corresponding radical anions. These complexes are non-fluorescent, allowing switching of the emission by changing the ligand oxidation state.
L’exposition osseuse au niveau de la crête tibiale distale est particulièrement difficile à recouvrir en raison notamment de la pauvreté des tissus mous adjacents disponibles, mais aussi de la ...précarité de la vascularisation locale. Le lambeau pédiculé perforant en hélice est une nouvelle méthode apportant des tissus mous similaires au niveau d’une perte de substance du membre inférieur, tout en évitant une longue et lourde procédure de reconstruction par lambeau libre ou un sacrifice musculaire local. Les auteurs présentent ici deux cas de reconstruction du tiers distal de la jambe : un cas d’exposition osseuse post-traumatique et un cas d’ostéomyélite chronique.
Distal lower leg soft tissue defect is frequently a challenge to repair, particularly on the tibial crest. The coverage of this kind of lesion has some limitations because of regional minimal blood supply and paucity of local soft-tissue flaps. The perforator pedicled propeller (PPP) method tries to find a new place in lower leg reconstruction in bringing similar tissues at the recipient site and avoiding long and difficult free flap transfer or muscular sacrifice. The authors report on the use of PPP method for a tibial crest exposure after trauma and for a soft tissue defect with osteomyelitis on the tibial crest.
Introduction La fibrose rétropéritonéale est caractérisée par le développement d’une masse fibreuse autour de structures rétropéritonéales. La fibrose péritonéale est idiopathique dans deux tiers des ...cas. La physiopathologie n’est pas clairement identifiée. Nous rapportons une observation clinique d’une association de la fibrose péritonéale idiopathique et diabète de type 1. Observation Il s’agit d’une patiente âgée de 61 ans, présentant un diabète de type 1 depuis l’âge de 43 ans. À 56 ans, est diagnostiquée une hydronéphrose bilatérale par compression urétérale extrinsèque. Le diagnostic de fibrose péritonéale idiopathique est posé. Le diabète est instable sous schéma multi-injections. L’examen clinique (IMC 25) ne retrouve pas l’anomalie particulière sauf une diminution des réflexes ostéotendineux aux membres inférieurs. L’HbA1C est à 8,5 %. Le C peptide est indosable. Les anticorps anti GAD positifs à 5,5 ku/ l (N < 1) et anticorps anti IA2 négatifs. Les haplotypes HLA de classe 2 montrent allèle DRB1*03. L’IgG et l’IgG4 sont normaux. Il n’y a pas de stéatorrhée. Les Ac anti DNA natif et Ac anti nucléaire sont négatifs. Le scanner abdominal ne montre pas de remaniements au niveau du pancréas, mais une dilatation des cavités urétéro-pyélocalicielles en rapport avec la fibrose rétropéritonéale. L’anatomopathologie des biopsies para-urétérales montre un tissu conjontivovasculaire remanié par une fibrose dense dissociée par un infiltrat inflammatoire chronique lympho-plasmocytaire modérément abondant et on conclut à une fibrose inflammatoire chronique. Conclusion À notre connaissance, il n’y pas précédemment décrit dans la littérature de cas d’association de diabète de type 1 et la fibrose rétropéritonéale. Devant ce diabète très instable avec de nombreuses hypoglycémies avec des besoins modérés en insuline, se pose la question d’une maladie autoimmune associant la fibrose rétropéritonéales et le diabète de type 1 du fait de l’absence de pancréatite chronique autoimmune.
An unprecedented strategy for preparing photoresponsive cellulose paper enabling the storage of short-lived optical data by covalent photopatterning is disclosed. An ab initio design hinting that the ...covalent grafting of coumarins on the paper could yield valuable photoresponsive units was first performed. Second, light sensitive paper that can be reversibly altered upon irradiation at a specific wavelength was prepared by covalent surface functionalization with coumarins. Third, the validity of this strategy is demonstrated using the photolithography of several gripping patterns such as a dynamic QR code.
We report the first density functional study of water catalytic effect in the double proton transfer (DPT) taking place in the adenine−thymine (AT) base pair. To gain more insight regarding the ...accuracy of several theoretical methods, the ability of various functionals and models for describing the geometry of this system has first been checked. According to our results, BP86/6-311++G(d,p) is the best option for describing the solvation effects in AT when applied to a two-water-molecule-featuring model. The two possible mechanisms for DPT in solution are explored: in the first one, water molecules only remain passive elements, whereas in the second one they are directly included in the reaction path. For the noncatalyzed mechanism, the stable structures constitute the canonical form of the base pair and the first proton transfer product. Nevertheless, by involving the two water molecules in the reaction, we found three stable species: canonical base pair, first proton transfer product, and double proton transfer product. Although the thermodynamic analysis confirms that AT does not contribute to spontaneous mutation through proton transfer catalyzed by surrounding water, our results suggest that microhydration may play a crucial role for DPT reaction in others DNA or RNA basis pair.
Ladanein, a 5,6,7-trihydroxylayted flavone was recently shown to display potent antiviral activities toward enveloped virus particles ( e.g. , hepatitis C virus, human immunodeficiency virus, ...vesicular stomatitis virus). Fe( iii ) coordination and pH were suggested to be critical for bioactivation steps triggering host cell entry inhibition. The Fe( iii ) complexation properties of ladanein and related analogues, such as negletein and salvigenin, were then studied in solution under quasi-physiological conditions using physico-chemical tools and provided important insights into their stability/reactivity in solution.
Lorsque des législations relatives à la fin de vie permettent aux patients de solliciter directement ou indirectement un geste conduisant à la mort, il importe de se demander ce qui se trouve ...effectivement demandé aux professionnels, de s’interroger sur ce qu’ils vivent et sur la manière dont la réponse offerte se trouve, d’un point de vue clinique et éthique, considérée individuellement et collectivement. Il importe que les enjeux de la décision et de l’action puissent être nommés – la mort – et intégrés dans la signification globale de l’acte professionnel, particulièrement en soins palliatifs. Le concept clinique et éthique de « transgression » en est un moyen privilégié.
While legislation relating to death and dying allow patients to solicit, in a direct or indirect manner, any assistance leading to death, it is important for the health professionals to verify what exactly is asked of them, to question what they live and the way they respond to the situation from a clinical and ethical point of view considered individually and collectively. It is important that the issues concerning the decision and the ensuing action be named – death – and be integrated within the global significance of the professional treatment, particularly in the context of palliative care. The clinical and ethical concept of “transgression” is one of the preferred means for achieving such a purpose.
Par respect du principe d’autonomie, les experts réunis en conférence de consensus recommandent de discuter de façon anticipée avec le patient atteint de sclérose latérale amyotrophique (SLA) du ...traitement de la défaillance respiratoire terminale (accompagner le décès par des soins palliatifs ou mettre en place une trachéotomie pour une suppléance ventilatoire de survie). La loi Leonetti inscrit un droit pour le patient de refuser une trachéotomie s’il la considère déraisonnable et prescrit aux médecins de tenir compte des directives anticipées sur le traitement de la défaillance respiratoire terminale qu’aura donné la personne avant son incapacité à communiquer. Deux écueils sont à éviter : que la visée de la relation médecin/patient soit l’obtention de ces directives anticipées et que la vulnérabilité du patient, avec ses ambivalences possibles, ne soit pas reconnue. Notre étude a porté sur 35 patients atteints de SLA pour lesquels la question anticipée d’une réanimation ou de soins palliatifs de fin de vie a pu être posée. Si la majorité des patients ont demandé à en être informé, 48 % n’ont jamais pu anticiper. Seulement 20 % ont exprimé des directives anticipées. Ces résultats montrent que la discussion est délicate et conduit à nous interroger sur la dimension éthique du concept d’autonomie, au-delà de sa formulation principliste : ne peut-on envisager l’incapacité de se confronter à la question existentielle de la mort possible ? Plus qu’un exercice de respect de l’autonomie de la personne, il s’agit ici d’un exercice de responsabilité médicale.
In accordance with the principle of personal autonomy, expert consensus statements on amyotrophic lateral sclerosis (ALS) recommend early engagement with terminal-phase patients on the type of symptomatic treatment to be administered in the event of respiratory failure, since decompensation progresses too rapidly to allow time for a discussion. The French Parliamentary Act on Patients’ Rights and End-of-Life Care (dated 22 April 2005) grants individuals the right to refuse unreasonable treatment and obliges physicians to take account of any prior instructions given by a person before he/she became incapable of communicating. The provision of prior instructions is a very reassuring situation for the physician: the autonomous patient indicates his or her choice of end-of-life care. However, there are two pitfalls which must be avoided: (i) holding a discussion for the sole purpose of obtaining prior instructions and (ii) not acknowledging the patient’s vulnerability. The present study dealt with 35 ALS patients for whom the question of either intensive care or palliative end-of-life care remained open. Even though the great majority of these individuals were keen to know their exact state of health, 48% refused to consider this circumstance and only 20% expressed prior instructions. These results prompted us to question the ethical dimension of the concept of autonomy beyond its founding formulation: can one envisage an incapacity to confront oneself with the existential question of possible death? In 80% of cases, the physician will have to take a care decision in the absence of any prior instructions from the patient. This amounts to more than respecting a person’s autonomy and involves exercising medical responsibility.
Breast surgery currently remains very subjective and each intervention depends on the ability and experience of the operator. To date, no objective measurement of this anatomical region can codify ...surgery. In this light, we wanted to compare and validate a new technique for 3D scanning (LifeViz 3D) and its clinical application. We tested the use of the 3D LifeViz system (Quantificare) to perform volumetric calculations in various settings (in situ in cadaveric dissection, of control prostheses, and in clinical patients) and we compared this system to other techniques (CT scanning and Archimedes’ principle) under the same conditions. We were able to identify the benefits (feasibility, safety, portability, and low patient stress) and limitations (underestimation of the in situ volume, subjectivity of contouring, and patient selection) of the LifeViz 3D system, concluding that the results are comparable with other measurement techniques. The prospects of this technology seem promising in numerous applications in clinical practice to limit the subjectivity of breast surgery.
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