Metal-Catalyzed, Photo-Assisted Selective Transformation of Tertiary Alkylbenzenes and Polystyrenes into Carbonyl Compounds.

Every year, thousands of tons of polystyrene are produced and discarded, filling landfills and polluting the marine environment. Although several degradation alternatives have been proposed, the need for an effective procedure for the chemical recycling of polystyrene still remains. Here, a vanadium-catalyzed reaction, assisted by visible light, promoted the direct, selective conversion of tertiary alkylbenzenes into acetophenone and other ketone derivatives. Likewise, standard polystyrene samples as well as polystyrenes from insulation and packaging waste could be chemically recycled into acetophenone in a scalable way regardless of their molecular weight, polydispersity, or form. Preliminary mechanistic investigations revealed the participation of singlet oxygen, superoxide, and hydroxyl radical species in this homogenously catalyzed process. Acetophenone could be used as an additive to accelerate the reaction and to increase the yields in some cases.

Direct Arylation in the Presence of Palladium Pincer Complexes.

Direct arylation is an atom-economical alternative to more established procedures such as Stille, Suzuki or Negishi arylation reactions. In comparison with other palladium sources and ligands, the use of palladium pincer complexes as catalysts or pre-catalysts for direct arylation has resulted in improved efficiency, higher reaction yields, and advantageous reaction conditions. In addition to a revision of the literature concerning intra- and intermolecular direct arylation reactions performed in the presence of palladium pincer complexes, the role of these remarkably active catalysts will also be discussed.

Terapia física en la hipofunción vestibular unilateral y bilateral / Physical therapy in unilateral and bilateral vestibular hypofunction

INTRODUCCIÓN: La rehabilitación vestibular (RV) basada en la terapia física, tiene el objetivo, en el caso de patología vestibular, de inducir la compensación del sistema nervioso central (SNC) a nivel de núcleos vestibulares y de otros niveles del SNC. Incluye ejercicios de habituación, adaptación y sustitución vestibular, ejercicios para mejorar el equilibrio y el control postural dinámico y ejercicios para el acondicionamiento general. En este capítulo discutimos los recientes avances sobre el adiestramiento del equilibrio y de la marcha, la estabilidad de la mirada y la habituación, en el contexto de los trastornos vestibulares uni y bilaterales. MÉTODO: Revisión narrativa. RESULTADOS: Los ejercicios se prescriben para mejorar la función; fortaleciendo, y favoreciendo la flexibilidad y la resistencia, a través de la adaptación del RVO, la habituación, la sustitución sensorial, la marcha y el equilibrio postural. Son más eficaces los programas personalizados que los genéricos. El cumplimiento mejora con la personalización y las visitas de seguimiento a un fisioterapeuta. Discusión/CONCLUSIONES: La RV permite mejorar el déficit funcional y los síntomas subjetivos derivados de la hipofunción vestibular periférica uni y bilateral, así como las alteraciones del equilibrio de origen central. Los objetivos de la RV consisten en reducir los síntomas para mejorar la estabilidad postural y de la mirada (particularmente durante los movimientos de la cabeza) y devolver al individuo a sus actividades normales, incluyendo la actividad física, la conducción y el trabajo habitual. Los médicos deben ofrecer la RV a quienes muestren limitaciones funcionales relacionadas con un déficit vestibular, pues actualmente se considera el tratamiento estándar en la disfunción vestibular periférica

INTRODUCTION: The vestibular rehabilitation is an exercise-based method, aiming to maximize central nervous system (CNS) compensation at vestibular nuclear and other CNS levels for vestibular pathology. Vestibular rehabilitation includes exercises to habituate symptoms, exercises to promote vestibular adaptation and substitution, exercises to improve balance and dynamic postural control, and exercises to improve general conditioning. Recent advances in balance and gait training, gaze stability training, habituation training, are discussed in this chapter in the context of unilateral and bilateral vestibular disorders. METHOD: Narrative review. RESULTS: Exercises are prescribed that address VOR adaptation, habituation, sensory substitution, gait and posture, strengthening, flexibility, and endurance to maximize functioning. Customized exercise programs have been shown to be more effective than providing a patient with a generic exercise program. It is thought that compliance is enhanced with customization and with follow-up visits with a physical therapist. Discussion/ conclusions: VR therapy is effective in improving functional deficits and subjective symptoms resulting from unilateral and bilateral peripheral vestibular hypo function, as well as from central balance disorders. The goals of vestibular rehabilitation are to reduce subjective symptoms, to improve gaze and postural stability (particularly during head movements), and to return the individual to normal activities, including regular physical activity, driving, and work. Clinicians should offer vestibular rehabilitation to persons with impairments and functional limitations related to the vestibular deficit. Vestibular rehabilitation is now considered the standard of care for persons with peripheral vestibular dysfunction

New Copper, Palladium and Nickel Catalytic Systems: An Evolution towards More Efficient Procedures.

Metal-catalysed reactions are a fundamental tool in synthetic chemistry. Increasingly challenging transformations can be accomplished only by means of certain metal catalysts. However, there still remains the need for a substantial decrease of the amount of catalyst, for better reuse or recycling of such active species, and for the avoidance of relatively toxic solvents in favour of environmentally friendly media. These facts apply to copper-, palladium-, and nickel-catalysed cross-coupling reactions, direct arylations, and oxidative processes. This account summarises our research on the last reactions, featuring an evolution towards more sustainable procedures in this field.

Synthesis, structure, and catalytic applications for ortho- and meta-carboranyl based NBN pincer-Pd complexes.

o- and m-Carborane-based NBN pincer palladium complexes (oCB-L1)Pd, (oCB-L2)Pd, and (mCB-L1)Pd are synthesized in two steps from commercially available starting materials. The pincer complexes were prepared by the reaction of bis-[R(hydroxy)methyl]-1,2-dicarba-closo-dodecaborane (R = 2-pyridyl oCB-L1, 6-methyl-2-pyridyl oCB-L2) or bis-[2-pyridyl (hydroxy)methyl]-1,2-dicarba-meta-dodecaborane (mCB-L1) with [PdCl2(MeCN)2] under mild conditions. The X-ray structure determination of all carboranyl pincer complexes shows unambiguously B-H activation of the carborane cages. The results agree with the Pd-B bonds in all complexes exhibiting strong σ-electron donation. Theoretical calculations reveal the importance of considering the solid state intermolecular hydrogen bonding when investigating the trans influence in organometallic chemistry. A localized orbitals approach has also been applied to analyze the metal oxidation state in the carboranyl pincer complexes. Catalytic applications of (oCB-L1)Pd and (mCB-L1)Pd have shown the complexes are good catalyst precursors in Suzuki coupling in water and with very low amounts of catalyst loadings.

An straightforward entry to new pyrazolo-fused dibenzo[1,4]diazepines.

A series of novel pyrazolodibenzo[1,4]diazepines has been synthesized with good overall yields. The diarylpyrazole intermediates, with structure similarity to biologically relevant compounds such as currently marketed drugs like rimonabant or celecoxib, were prepared by a tandem sequence amine-exchange/heterocyclization starting from readily available enaminones and arylhydrazines. The key step of this efficient methodology was C(aryl)-N bond construction, accomplished by a palladium-catalyzed intramolecular N-arylation reaction, which was conducted in both homogeneous and polymer-supported versions. Reaction scope of such protocols and recycling of the heterogeneous catalyst were also examined.

Toward safer processes for C-C biaryl bond construction: catalytic direct C-H arylation and tin-free radical coupling in the synthesis of pyrazolophenanthridines.

A series of pyrazolo[1,5-f]phenanthridine derivatives has been efficiently synthesized by a short, straightforward sequence. A tandem amine-exchange/heterocyclization of enaminones was successfully applied to the regioselective preparation of 1,5-diarylpyrazole intermediates with structure resemblance to relevant nonsteroidal anti-inflammatory drugs such as celecoxib or tepoxalin. The final key step, cyclization by intramolecular biaryl bond formation, was accomplished by two alternative methodologies: radical coupling and catalytic direct arylation via C-H activation. The scope and limitations of the two methodologies have been explored and their complementariness has been established. In addition, polymer-supported heterogeneous catalysts have been compared with homogeneous analogues. In the radical process, toxic tin derivatives have been avoided in order to employ environmentally safer protocols.

Obesity and overweight prevalences in rural and urban populations in East Spain and its association with undiagnosed hypertension and Diabetes Mellitus: a cross-sectional population-based survey.

BACKGROUND: An increase in the number of overweight and obese subjects in the general population has been observed.The aim of this study was to determine the prevalence of overweight and obese subjects in the general population and its association with undiagnosed pathologies, such as diabetes mellitus [DM] and hypertension [HT], by taking age, gender and place of residence [rural or urban] into account. FINDINGS: A cross-sectional population-based survey was conducted in Castellón, East Spain in 2005-2006. The sample included 2,062 participants aged 18-94 years. Weight, height, blood pressure and glycaemia values were recorded, and information about gender, age and place of residence was obtained. Overweight, obesity, and undiagnosed HT and DM prevalences were calculated. Multiple regression analyses were done to assess the association of overweight/obesity with undiagnosed HT and DM by adjusting for age, gender and place of residence.The overall overweight, obesity, and undiagnosed HT and DM prevalences were 39.9% [95% CI:37.3-42.0], 25.9% [95% CI:24.0-27.9], 9.0% [95% CI:7.8-10.4] and 12.6% [95% CI:11.2-14.1], respectively. We identified various independent risk factors; those relating to overweight were increasing age, male gender and rural residential area, while that relating to obesity was increasing age. Compared to normal weight adults, the Relative Prevalence Ratio (RPR) for subjects who were overweight and had HT was 2.00 [95% CI:1.21-3.32]; that for obesity and HT was 1.91 [95% CI:1.48-2.46], and it was 1.50 [95% CI:1.25-1.81] for obesity and DM. CONCLUSION: Overweight and obesity prevalences, and their association with undiagnosed DM and HT, are high in our study population.