Three-dimensional recording by tightly focused femtosecond pulses in LiNbO₃

The authors report on a three-dimensional single-shot optical recording by 150fs pulses at 800nm wavelength in Fe doped LiNbO₃. The rewritable bits (2ₓ×2y×8zμm³) are demonstrated. The highest refractive index modulation of ∼10⁻³ per single pulse has been formed by preferential photovoltaiceffect at close to the dielectric breakdownirradiance of ∼TW/cm² and was independent of polarization (in respect to the c axis). The achievable refractive index modulation is evaluated and the recording mechanisms are discussed.One of the authors M.S. thanks the Matsumae International Foundation for the research fellowship. Another author E.G.G. acknowledges support of the Australian Research Council through its Center of Excellence

Construction of uricase-overproducing strains of Hansenula polymorpha and its application as biological recognition element in microbial urate biosensor

<p>Abstract</p> <p>Background</p> <p>The detection and quantification of uric acid in human physiological fluids is of great importance in the diagnosis and therapy of patients suffering from a range of disorders associated with altered purine metabolism, most notably gout and hyperuricaemia. The fabrication of cheap and reliable urate-selective amperometric biosensors is a challenging task.</p> <p>Results</p> <p>A urate-selective microbial biosensor was developed using cells of the recombinant thermotolerant methylotrophic yeast <it>Hansenula polymorpha </it>as biorecognition element. The construction of uricase (UOX) producing yeast by over-expression of the uricase gene of <it>H. polymorpha </it>is described. Following a preliminary screening of the transformants with increased UOX activity in permeabilized yeast cells the optimal cultivation conditions for maximal UOX yield namely a 40-fold increase in UOX activity were determined.</p> <p>The UOX producing cells were coupled to horseradish peroxidase and immobilized on graphite electrodes by physical entrapment behind a dialysis membrane. A high urate selectivity with a detection limit of about 8 μM was found.</p> <p>Conclusion</p> <p>A strain of <it>H. polymorpha </it>overproducing UOX was constructed. A cheap urate selective microbial biosensor was developed.</p

A C=O⋅⋅⋅Isothiouronium Interaction Dictates Enantiodiscrimination in Acylative Kinetic Resolutions of Tertiary Heterocyclic Alcohols

The research leading to these results has received funding from the ERC under the European Union's Seventh Framework Programme (FP7/2007-2013)/E.R.C. grant agreement n° 279850 and the EPSRC (EP/J500549/1). A.D.S. thanks the Royal Society for a Wolfson Research Merit Award. P.H.-Y.C. is the Bert and Emelyn Christensen Professor and gratefully acknowledges financial support from the Stone Family of OSU. Financial support from the National Science Foundation (NSF) (CHE-1352663) is acknowledged. D.M.W. acknowledges the Bruce Graham and Johnson Fellowships of OSU. D.M.W. and P.H.-Y.C. acknowledge computing infrastructure in part provided by the NSF Phase-2 CCI, Center for Sustainable Materials Chemistry (CHE-1102637).A combination of experimental and computational studies have identified a C=O•••isothiouronium interaction as key to efficient enantiodiscrimination in the kinetic resolution of tertiary heterocyclic alcohols bearing up to three potential recognition motifs at the stereogenic tertiary carbinol center. This discrimination was exploited in the isothiourea-catalyzed acylative kinetic resolution of tertiary heterocyclic alcohols (38 examples, s factors up to > 200). The reaction proceeds at low catalyst loadings (generally 1 mol %) with either isobutyric or acetic anhydride as the acylating agent under mild conditionsPostprintPeer reviewe

A C=O⋅⋅⋅Isothiouronium Interaction Dictates Enantiodiscrimination in Acylative Kinetic Resolutions of Tertiary Heterocyclic Alcohols

A combination of experimental and computational studies have identified a C=O⋅⋅⋅isothiouronium interaction as key to efficient enantiodiscrimination in the kinetic resolution of tertiary heterocyclic alcohols bearing up to three potential recognition motifs at the stereogenic tertiary carbinol center. This discrimination was exploited in the isothiourea-catalyzed acylative kinetic resolution of tertiary heterocyclic alcohols (38 examples, s factors up to &gt;200). The reaction proceeds at low catalyst loadings (generally 1 mol %) with either isobutyric or acetic anhydride as the acylating agent under mild conditions.</p

Antología del pensamiento crítico boliviano contemporáneo

La Antología que presentamos se estructura sobre la base de cuatro ejes de negación ante la centralidad absorbente de la narrativa oficial. Nos negamos al eurocentrismo convocando a pensadores y pensadoras indígenas de diversas vocaciones teóricas y prácticas metodológicas. Nos negamos al antropocentrismo introduciendo textos que hablan de la relación humana con el paisaje, con la espiritualidad y con la naturaleza. Lxs protagonistas de este libro profesan formas análogas a la praxis de los "antiguos caminantes" que recorrieron los espacios andinos y amazónicos en pos del "buen gobierno" y del "buen vivir". Pero este eje tiene sus propios márgenes. Nos negamos al logocentrismo del discurso oficial y proponemos el ámbito de la música, la imagen y la reflexión poética como grietas que abren caminos hacia un pensar más acorde con los tiempos y ritmos de la crisis planetaria. Y nos negamos al androcentrismo prestando atención a las voces del cuerpo: mujeres transgresoras, transformistas y homosexuales. Estas cuatro negaciones quieren ser también afirmaciones: grietas en el poder monológico del Estado, por donde broten aguas renovadas de pensamiento y práctica, desde espacios descentrados y diversos