The study investigates the chemical stability of lipids used as excipients in the production of solid lipid nanoparticles (SLN). A total of 17 SLN formulations was produced using different lipids. ...Most of the formulations were produced using identical binary surfactant mixtures and
concentrations to study the effect of the chemical nature of the lipid on its stability in SLN. In some formulations surfactants were exchanged to study the contribution of the surfactant. The particles were characterised by photon correlation spectroscopy, laser diffractometry, zeta potential
determination and differential scanning calorimetry, the latter to assess potential effects of lipid crystallinity and modifications on lipid stability. Lipid analysis was performed by gas chromatography using a sampling preparation and analysis procedure especially developed for SLN. This
short-term study provides primarily information about the stability of the lipid under production conditions, that means high pressure homogenisation (cavitation) at high temperature. No degradation products could be detected for all lipids, the production process itself did not impair excipient
stability.
Stable microemulsions oil-in-water (o/w) and water-in-oil (w/o) with timolol were obtained. These formulations were sterilized using two methods: by autoclaving and by sterile filtering according to ...the Polish Pharmacopeia V. Microemulsions were kept in the temperatures of 25 °C
and 5 °C during three months. The following physical parameters were investigated: density, dynamic viscosity, refractive index, surface tension, pH and osmotic tension. All the microemulsions met the requirements for eye drops.
Given two ordinary elliptic curves over a finite field
having the same cardinality and endomorphism ring, it is known that
the curves admit a nonzero isogeny between them, but finding such an
isogeny ...is believed to be computationally difficult. The fastest
known classical algorithm takes exponential time, and prior to our
work no faster quantum algorithm was known. Recently, public-key
cryptosystems based on the presumed hardness of this problem have
been proposed as candidates for post-quantum cryptography. In this
paper, we give a new subexponential-time quantum algorithm for
constructing nonzero isogenies between two such elliptic curves,
assuming the Generalized Riemann Hypothesis (but with no other
assumptions). Our algorithm is based on a reduction to a hidden
shift problem, and represents the first nontrivial application of
Kuperberg's quantum algorithm for finding hidden shifts. This
result suggests that isogeny-based cryptosystems may be
uncompetitive with more mainstream quantum-resistant cryptosystems
such as lattice-based cryptosystems. As part of this work, we also
present the first classical algorithm for evaluating isogenies
having provably subexponential running time in the cardinality
of the base field under GRH.
O2 was electroreduced to water, at a true-surface-area-based current density of 0.5 mA cm-2, at 37 °C and at pH 5 on a “wired” laccase bioelectrocatalyst-coated carbon fiber cathode. The polarization ...(potential vs the reversible potential of the O2 /H2O half-cell in the same electrolyte) of the cathode was only −0.07 V, approximately one-fifth of the −0.37 V polarization of a smooth platinum fiber cathode, operating in its optimal electrolyte, 0.5 M H2SO4. The bioelectrocatalyst was formed by “wiring” laccase to carbon through an electron conducting redox hydrogel, its redox functions tethered through long and flexible spacers to its cross-linked and hydrated polymer. Incorporation of the tethers increased the apparent electron diffusion coefficient 100-fold to (7.6 ± 0.3) × 10-7 cm 2 s-1. A miniature single-compartment glucose−O2 biofuel cell made with the novel cathode operated optimally at 0.88 V, the highest operating voltage for a compartmentless miniature fuel cell.
The origin of the tropical lower-stratospheric response to 11-yr solar forcing and its possible coupling to a troposphere-ocean response is investigated using multiple linear regression (MLR) ...analyses of stratospheric ozone and temperature data over the 1979-2009 period and tropospheric sea level pressure (SLP) data over the 1880-2009 period. Stratospheric MLR results, comparisons with simulations from a chemistry-climate model, and analyses of decadal variations of meridional eddy heat flux indicate that the tropical lower-stratospheric response is produced mainly by a solar-induced modulation of the Brewer-Dobson circulation (BDC), with a secondary contribution from the Hadley circulation in the lowermost stratosphere. MLR analyses of long-term SLP data confirm previous results indicating a distinct positive response, on average, during the northern winter season in the North Pacific. The mean response in the Northern Hemisphere resembles a positive Arctic Oscillation mode and can also be characterized as "La Nina-like," implying a reduction of Rossby wave forcing, a weakening of the BDC, and an increase in tropical lower-stratospheric ozone and temperature near solar maxima. However, MLR analyses of different time periods show that the Pacific SLP response is not always present during every cycle; it was most clearly detected mainly during the ~1938-93 period when 11-yr solar variability was especially strong. During the 1979-93 period, the SLP response was strongly present when the lower-stratospheric responses were large. But during the 1994-2009 period, the SLP response was much less significant and the lower-stratospheric responses were weak, supporting the hypothesis that the lower-stratospheric and surface climate responses are dynamically coupled.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Password authenticated key establishment (PAKE) is a cryptographic primitive that allows two parties who share a low-entropy secret (a password) to securely establish cryptographic keys in the ...absence of public key infrastructure. We propose the first quantum-resistant password-authenticated key exchange scheme based on supersingular elliptic curve isogenies. The scheme is built upon supersingular isogeny Diffie-Hellman
, and uses the password to generate permutations which obscure the auxiliary points. We include elements of a security proof, and discuss roadblocks to obtaining a proof in the BPR model
. We also include some performance results.
Laccase was earlier wired to yield an O2 electroreduction catalyst greatly outperforming platinum and its alloys. Here we describe the design, synthesis optimization of the composition, and ...characterization of the +0.55 V (AgAgCl) laccase-wiring redox hydrogel, with an apparent electron diffusion coefficient (D app) of 7.6 × 10-7 cm2 s-1. The high D app results in the tethering of redox centers to the polymer backbone through eight-atom-long spacer arms, which facilitate collisional electron transfer between proximal redox centers. The O2 flux-limited, true-area-based current density was increased from the earlier reported 560 to 860 μA cm-2. When the O2 diffusion to the 7-μm-diameter carbon fiber cathode was cylindrical, half of the O2 flux-limited current was reached already at 0.62 V and 90% at 0.56 V vs Ag/AgCl, merely −0.08 and −0.14 V versus the 0.7 V (Ag/AgCl) reversible O2/H2O half-cell potential at pH 5.
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