The Total Synthesis Of (-)-cryptocaryol A

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)A stereoselective total synthesis of (-)-cryptocaryol A (1) is described. Key features of the 17-step route include the use of three boron-mediated aldol reaction-reduction sequences to control all stereocenters and an Ando modification of the Horner-Wadsworth-Emmons olefination that permitted the installation of the Z double bond of the alpha-pyrone ring.131235753584Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAEP-UNICAMPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPq [Proc. 573.564/2008-6]FAPESP [2012/02230-0, 2013/07600-3

The effects of stellar winds on the magnetospheres and potential habitability of exoplanets

Context: The principle definition of habitability for exoplanets is whether they can sustain liquid water on their surfaces, i.e. that they orbit within the habitable zone. However, the planet's magnetosphere should also be considered, since without it, an exoplanet's atmosphere may be eroded away by stellar winds. Aims: The aim of this paper is to investigate magnetospheric protection of a planet from the effects of stellar winds from solar-mass stars. Methods: We study hypothetical Earth-like exoplanets orbiting in the host star's habitable zone for a sample of 124 solar-mass stars. These are targets that have been observed by the Bcool collaboration. Using two wind models, we calculate the magnetospheric extent of each exoplanet. These wind models are computationally inexpensive and allow the community to quickly estimate the magnetospheric size of magnetised Earth-analogues orbiting cool stars. Results: Most of the simulated planets in our sample can maintain a magnetosphere of ~5 Earth radii or larger. This suggests that magnetised Earth analogues in the habitable zones of solar analogues are able to protect their atmospheres and is in contrast to planets around young active M dwarfs. In general, we find that Earth-analogues around solar-type stars, of age 1.5 Gyr or older, can maintain at least a Paleoarchean Earth sized magnetosphere. Our results indicate that planets around 0.6 - 0.8 solar-mass stars on the low activity side of the Vaughan-Preston gap are the optimum observing targets for habitable Earth analogues.Comment: 8 pages, 3 figures, accepted to Astronomy and Astrophysic

Foraminifera from a mangrove transect at the Cardoso Island (Cananéia-Iguape System/SP), Brazil

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POLYMER MELT FLOW IN SUDDEN EXPANSIONS: THE EFFECTS OF VISCOUS HEATING

Sudden expansion is a typical geometry found at the entrance of a mould cavity and is generally known in industry as ‘gate’. Flow simulation of this class of problems poses some difficulties owing to coupling of momentum and energy laws, existence of re-circulation and steep pressure variations. This work focuses on the physical analysis of the laminar and incompressible polymer melt flow inside channels with sudden expansions aimed at mapping the viscous heating effect. The mathematical model comprises the mass, momentum and energy conservation laws. The pressure-velocity coupling is treated on solving a Poisson equation for pressure. The Cross constitutive model is adopted to describe the non-Newtonian behavior of the flow. The governing equations are discretized using the finite difference method based on central, second order accurate formulae for both convective and diffusive terms. Artificial smoothing terms are added to control the odd-even decoupling problem. The main results demonstrate that the flow parameters, such as pressure drop along the channel and Nusselt number at the walls, are affected by viscous heating. It has been found that, in such problems, any reliable solution must account for the non-isothermal effects

Metal-catalyzed asymmetric aldol reactions

The aldol reaction is one of the most powerful and versatile methods for the construction of C-C bonds. Traditionally, this reaction was developed in a stoichiometric version; however, great efforts in the development of chiral catalysts for aldol reactions were performed in recent years. Thus, in this review article, the development of metal-mediated chiral catalysts in Mukaiyama-type aldol reaction, reductive aldol reaction and direct aldol reaction are discussed. Moreover, the application of these catalysts in the total synthesis of complex molecules is discussed.A reação aldólica é uma das ferramentas mais poderosas e versáteis para a construção de ligações C-C. Tradicionalmente, esta reação foi desenvolvida em sua versão estequiométrica, no entanto, grandes esforços no desenvolvimento de catalisadores quirais para reações aldólicas foram realizados nos últimos anos. Desta forma, neste artigo de revisão, é discutido o desenvolvimento de catalisadores metálicos em reação aldólica do tipo Mukaiyama, reação aldólica redutiva e reação aldólica direta. Além disto, a aplicação destes catalisadores na síntese total de moléculas complexas será abordada.21372158Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Secondary healing strategy for difficult wound closure in invasive vulvar cancer: a pilot case-control study

OBJECTIVES: Despite the number of surgical advances and innovations in techniques over time, radical vulvectomy frequently results in substantial loss of tissue that cannot be primarily closed without tension, the mobilization of surrounding tissues or even the rotation of myocutaneous flaps. The aim of this study was to evaluate the feasibility of leaving the surgical vulvar open wound for secondary healing in situations where primary closure of the vulvar wound is not possible. METHODS: This case-control pilot study analyzed 16 women with a diagnosis of squamous cell carcinoma of the vulva who first underwent inguinofemoral lymphadenectomy, 6-week sessions of chemotherapy and 25 daily sessions of radiotherapy. Afterward, excision of the vulvar lesion with free margins was performed between January 2011 and July 2017. Twelve patients underwent primary closure of the wound (control), and in 4 patients, the surgical wound was left open for secondary healing by means of a hydrofiber (case). The inclusion criteria were a) FIGO-2009 stage II up to IIIC; b) squamous cell carcinoma; and c) no evidence of pelvic or extrapelvic disease or pelvic nodal involvement. The exclusion criteria were extrapelvic disease or pelvic nodal involvement, another primary cancer, or a poor clinical condition. ClinicalTrials.gov: NCT02067052. RESULTS: The mean age of the patients at the time of the intervention was 62.1. The distribution of the stages was as follows: II, n=6 (37 %); IIIA, n=1 (6%), IIIB, n=1 (6%) and IIIC, n=8 (51%). The mean operative time was 45 minutes. The hospital stay duration was 2 days. Full vulvar healing occurred after an average of 30 days in the control group and after an average of 50 days in the case group. CONCLUSION: A secondary healing strategy may be an option for the treatment of vulvar cancer in situations of non-extensive surgical wounds when primary closure of the wound is not possible