Programming DNA-Based Systems through Effective Molarity Enforced by Biomolecular Confinement

The fundamental concept of effective molarity is observed in a variety of biological processes, such as protein compartmentalization within organelles, membrane localization and signaling paths. To control molecular encountering and promote effective interactions, nature places biomolecules in specific sites inside the cell in order to generate a high, localized concentration different from the bulk concentration. Inspired by this mechanism, scientists have artificially recreated in the lab the same strategy to actuate and control artificial DNA-based functional systems. Here, it is discussed how harnessing effective molarity has led to the development of a number of proximity-induced strategies, with applications ranging from DNA-templated organic chemistry and catalysis, to biosensing and protein-supported DNA assembly.     

Preparation and characterization of chloroaluminum phthalocyanine-loaded solid lipid nanoparticles by thermal analysis and powder X-ray diffraction techniques

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 °C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.     

Electron Paramagnetic Resonance Analysis of La(1-x)M(x)MnO(3+δ) (M = Ce, Sr) Perovskite-Like Nanostructured Catalysts

The physical-chemical properties of some nanostructured perovskite-like catalysts of general formula La(1-x)M(x)MnO(3+δ) (M = Ce, Sr) have been investigated, in particular by using the electron paramagnetic resonance (EPR) technique. We show that the interplay between the -O-Mn(3+)-O-Mn(4+)-O- electron double-exchange and the electron mobility is strictly dependent on the dopant nature and the annealing conditions in air. A relationship between the observed properties of these samples and their activity in the methane flameless catalytic combustion is proposed.     

High peak power and sub-picosecond Fourier-limited pulse generation from passively mode-locked monolithic two-section gain-guided tapered InGaAs quantum-dot lasers

We report on the development of a new generation of high-power ultrashort pulse quantum-dot lasers with tapered gain section. Two device designs are proposed and fabricated, with different total lengths and absorber-to-gain-section length-ratios. These designs have been informed by numerical simulations of the dynamic mode-locking regimes and their dependence on the structural parameters. One device design demonstrated a record-high peak power of 17.7 W with 1.26 ps pulse width and a second design enabled the generation of a Fourier-limited 672 fs pulse width with a peak power of 3.8 W. A maximum output average power of 288 mW with 28.7 pJ pulse energy was also attained. In addition, the integrated timing jitter of 2.6 ps and far-field patterns are demonstrated.     

12C18O2: High-resolution emission spectra in the 4.5-μm region rovibrational transitions 0v′2v3 → 0v′2(v3 − 1), v2 = l

Emission spectra of gaseous mixtures involving isotopic species of CO₂ excited by a dc discharge were recorded under Doppler-limited resolution, using a high-information Fourier Transform Interferometer, in the region 4–5 μm. In this paper are given the results concerning 34 vibrational transitions (Δv₃ = 1), for ¹²C¹⁸O₂. The band centers and the spectroscopic constants for the 39 vibrational levels involved are reported. They reproduce more than 1000 experimental wavenumbers with a RMS of the order of 2 × 10^?5 cm^?1 for the best vibrational transition and less than 3 × 10^?4 cm^?1 for most of the others. From a weighted simultaneous fit of all the experimental wavenumbers belonging to the Σ-Σ transitions, a set of molecular parameters was computed. A good reproduction of the experimental wavenumbers was obtained for all the vibrational transitions except those involving the level v₃ = 9, our conclusion being that a local vibrational perturbation exists for this level.     

Vibrational luminescence of CO2 excited by dc discharge: Rotational and vibrational molecular constants

High-resolution measurements have been performed on 33 emission bands of the carbon dioxide molecule from 4.2 to 4.7 μm. Accurate values of the vibrational and rotational constants of 39 vibration levels were obtained. Molecular constants were calculated from observed wavenumbers.     

Peptide mapping through the coupling of capillary electrophoresis and high-performance liquid chromatography: map prediction of the tryptic digest of myoglobin.

The tryptic map of horse myoglobin was analysed through capillary electrophoresis using capillaries modified by a monolayer of acrylamide. The results were reproducible and the map was obtained in less than 30 min from ca. 8 pmol of tryptic digest. The peptide identification was performed using peptides previously identified by high-performance liquid chromatography. The peak areas measured using the two techniques are closely related, and the comparison of elution and migration times shows that the two techniques provide different maps. Furthermore, using the semiempirical relationship suggested by Grossman et al. [Anal. Biochem., 179 (1989) 28], which links the electrophoretic mobility to the charge of the peptide and its number of amino acids, a good agreement between predicted and experimental mobilities was observed.