Amyloid-mediated synthesis of giant, fluorescent, gold single crystals and their hybrid sandwiched composites driven by liquid crystalline interactions

We report for the first time on the templating effect of β-lactoglobulin amyloid-like fibrils to synthesize gold single crystals of several decades of μm in dimensions. The gold single crystals were produced by reducing an aqueous solution of chloroauric acid by β-lactoglobulin amyloid protein fibrils. Atomic force microscopy, conventional and scanning transmission electron microscopy, electron diffraction and optical microscopy techniques were combined to characterize the structure of the gold crystals. The single-crystalline features of these macroscopic gold crystals are witnessed by their distinctive hexagonal and triangular shape and are confirmed by selected area electron diffraction (SAED). UV-vis absorption spectrum, recorded after a reaction time of 6h at the heating temperature of 55°C showed a surface plasmon resonance peak at 540 nm. With the increase of reaction time to 24h, the absorption spectrum peaks shift to a very broad and higher wavelength region extending up to near infrared region. Remarkably, these single crystalline gold crystals show auto fluorescence when illuminated to UV lamp. Further increase in β-lactoglobulin amyloid fibrils concentration above the isotropic-nematic transition, drives the formation of gold single crystals microplates stacking together and self-assembling into new hierarchical, layered protein-gold hybrid composites.     

New biocompatible thermo-reversible hydrogels from PNiPAM-decorated amyloid fibrils

New biocompatible temperature-responsive hydrogels have been obtained by using unprecedented low concentration of amyloid fibril-PNiPAM hybrids. The viscoelasticity of the hydrogels can be finely controlled by tuning the PNiPAM layers without changing the structure or concentration of the amyloid fibrils.     

Well-posedness of the two-dimensional nonlinear Schrödinger equation with concentrated nonlinearity

We consider a two-dimensional nonlinear Schrödinger equation with concentrated nonlinearity. In both the focusing and defocusing case we prove local well-posedness, i.e., existence and uniqueness of the solution for short times, as well as energy and mass conservation. In addition, we prove that this implies global existence in the defocusing case, irrespective of the power of the nonlinearity, while in the focusing case blowing-up solutions may arise.     

Amplified spontaneous emission in dye-laser systems for single photon amplification

A longitudinally pumped dye-laser amplifier is numerically investigated for the amplification of a very low intensity signal (as low as one photon per pulse), which is easily hindered by the simultaneous amplification of spontaneous emission. From the relevant set of coupled rate equations for population and photon fluxes the spatial dependence of these quantities is accounted for. The equations are solved numerically in some significant practical situations. The results describe the dependence of the amplified-spontaneous-emission (ASE) output flux on the pumping rate, on the spectral narrowing process and on the total spontaneous emission for a pulse in the selected angular width. The performance of dye-laser amplifiers is described by the same set of equations, and the gain characteristics of such systems are analyzed as functions of the pumping rate.     

1H NMR study of water relaxation and self-diffusion in human serum albumin aqueous solutions

Summary Water proton spin-lattice relaxation and self-diffusion in aqueous solutions of human serum albumin have been studied by¹H NMR as a function of the protein concentration. Spin-lattice relaxation data, which display a nonlinear behaviour with the protein concentration, could be fitted with a two-phase model taking into account the experimentally determined hydration (?bound?) water values. Despite a similar trend is registered for the water self-diffusion coefficient, such a model has been found unable to explain the related experimental data taken as a function of the biomolecule concentration. On the other hand, the solute-induced proton self-diffusion decrease could be satisfactorily interpreted by postulating an enhanced probability of hydrogen-bond formation occurring within the ?vicinal? water surrounding the biomolecules for several hydration shells. The consistency within the two models is discussed in connection with the magnetic interactions occurring within the solute-solvent systems.     

Isolement et identification de l'évernine dans la «mousse de chêne» (Evernia prunastri (L.) Ach.). 2e Communication

Isolation and identification of evernine in ‘Oakmosse’ (Evernia prunastri (L. ) Ach.). A new depside, evernin ( 1 ), has been found in the lichen Evernia Prunastri (L. ) Ach. The determination of the structure and the spectral parameters of 1 , especially the ¹³C-NMR. spectrum, are described.     

Isolement et identification de composés phénoliques et monoterpéniques de la mousse de chêne (Evernia prunastri (L.) Ach.)

The composition of different oakmoss extracts was investigated by combined gas chromatography/mass spectrometry. A series of 38 compounds – especially phenol derivatives and monoterpenes – was identified, 22 of which have not yet been reported as constituents of oakmoss.     

A proton NMR study of water in hydrated sodium β-alumina

Proton nmr study of hydrated sodium β-alumina reveals a Pake doublet spectrum due to stationary water molecules. As the temperature is increased from -196C to 192C, linewidth changes indicate that the stationary protons sense the increasingly rapid motion of nearby sodium nuclei and other protons. The interproton spacing computed from the spectra was found to be 1.7A.     

Collisional transfer of rotovibrational energy from quantum calculations

Summary A newly obtained anisotropic interaction for the He−N₂ system is here employed to analyse in detail the inelastic flux distribution between the many rotational states of the target molecule and the few of its vibrational states that are accessible at near-thermal ranges of collisional energy. Both integral and differential inelastic cross-sections are obtained from a quantal formulation of the energy transfer process, within which the orientational dependence of rotational and vibrational couplings is examined for its bearing on the interference structures that are exhibited by the dynamical observables as functions of final rotational states and of centre-of-mass scattering angles. Similarities and differences with previously studied polar molecules also interacting with helium are underlined and explained.

---

Riassunto Una superficie di potenziale recentemente ottenuta da noi per il sistema He−N₂ è utilizzata per studiare il processo quantico di transferimento d'energia interna, per via collisionale, fra i numerosi livelli rotazionali della molecola bersaglio ed alcuni dei livelli vibrazionali che risultano energeticamente accessibili alle velocità traslazionali qui esaminate. La natura anisotropa dell'accoppiamento (V, T) è così analizzata dal punto di vista del suo effettodiretto su osservabili dinamiche come sezioni d'urto inelastiche, parziali integrali e differenziali. Le strutture interferenziali che si originano in tale sistema sono scarsamente influenzate dalla presenza o meno di accoppiamento vibrazionale e sono qui discusse in relazione alla loro diversità con altri sistemi polari (LH, KF) precedentemente da noi studiati con tecniche teoriche simili.

---

Резюме Недавно полученное анизотропное взаимодействие для He−N₂ систем испоиьзуется в зтой работе для поробного анализа квантового переноса внутренней знергии меЗду многочисленными ротационными состояниями молекул мишени и несколькими колебатэльными состояниями. Анализируется природа анизотропии вращательіх и колебательньіх связей с точки зрения влияния зтой анизотропии на динамичэскиэ наблюдаемье величины, такиэ как интэграиьіе и дифференциалъные неупругие поперечные сеч∈ния. Интерферендионные структуры, которы∈ возникют в таких системах, слабо зависят от вибрадионной связх. Проводится сравнениэ полученных резульіх резулвтатоб с резулвтатми для других полярных молекул, ранее рассмотренных в рамках того Зе теоретическочо подхода.