Design of axially super-resolving phase filters using the method of generalized projections

The design of pupil phase filters that super-resolve the axial intensity distribution with controlled side-lobe peak intensity under high numerical aperture conditions can be accomplished by incorporating the theory of electromagnetic diffraction in the method of generalized projections (MGP). The MGP results are however strongly dependent on the starting conditions and the applied constraints. In this report we study this dependence by investigating different starting pupil functions and introducing modifications to the applied constraints. Methods are described and implemented to generate a systematic set of starting conditions that enable a more thorough search of the solutions space. This approach generated results for which 95% have a super-resolved central-lobe, yet only a subset of those solutions offer a satisfactory compromise between super-resolution of the central-lobe and increased intensity of the axial side-lobes. These solutions are presented and discussed in the context of specific applications.     

Preparation and antibacterial activity of copper and cobalt complexes of 4-chloro-3-nitrobenzoate with a nitrogen donor ligand

Copper and cobalt complexes with 4-chloro-3-nitrobenzoate (ClNBz) and the nitrogen ligands 1,3-diaminopropane (1,3-DAP) or o-phenylenediamine (o-PDA), were prepared and characterized. The complexes [Cu(ClNBz)2(1,3-DAP)] (1), [Cu(ClNBz)(o-PDA)]Cl (2), [Co(ClNBz)2(1,3-DAP)] (3) and [Co(ClNBz)2(o-PDA)2] (4) were characterized by FTIR, UV-Visible absorption, elemental analysis and thermal analysis. Complex [Cu(ClNBz)(o-PDA)]Cl (2) shows high antibacterial activity as indicated by its ability to inhibit the growth of Staphylococcus aureus, Enterococcus faecalis.     

Stereochemistry-60 : Kinetic control of asymmetric induction during oxazolidine formation from (-)-ephedrine and aromatic aldehydes

Kinetically controlled oxazolidine formation was observed with aromatic aldehydes substituted by electron-withdrawing groups. The stereoselectivity is solvent dependent: non-stereoselective ring closure occurred in chloroform while a high diastereodifferentiation was observed in methanol. The first oxazolidine showing an unambiguous 2R configuration was synthesized from p-bromobenzaldehyde and (-)-ephedrine in alcohol medium. A mechanism involving a nucleophilic assistance by alcoholic solvents is suggested in order to clarify the differences in stereoselectivity.     

The Small Scales of the Stochastic Navier–Stokes Equations Under Rough Forcing

We prove that the small scale structures of the stochastically forced Navier–Stokes equations approach those of the naturally associated Ornstein–Uhlenbeck process as the scales get smaller. Precisely, we prove that the rescaled kth spatial Fourier mode converges weakly on path space to an associated Ornstein–Uhlenbeck process as |k| . In addition, we prove that the Navier–Stokes equations and the naturally associated Ornstein–Uhlenbeck process induce equivalent transition densities if the viscosity is replaced with hyper-viscosity. This gives a simple proof of unique ergodicity for the hyperviscous Navier–Stokes system. We show how different strengthened hyperviscosity produce varying levels of equivalence.     

Stationary measures for a randomly forced burgers equation

We study a randomly forced Burgers equation and its corresponding Hamilton‐Jacobi equation on the line. The forcing is of the form of a randomly modulated and shifted potential. We prove the existence of invariant probability measures and provide examples for which these measures are not unique. These measures do exhibit certain ergodic behavior. The methods we use are closely connected to the Lax‐Ole?inik variational principle. © 2004 Wiley Periodicals, Inc.     

Mechanical and morphological properties of injection-molded rice husk polypropylene composites

In this work, the investigation of the physical, mechanical, and morphological properties of the rice husk flour/polypropylene composites was performed utilizing various filler loadings and coupling agent. Five levels of filler loading (35, 40, 45, 50, and 55 wt%) were designed. In addition, to help the interaction between fiber and polypropylene matrix, struktol coupling agent was added to the composites. All of tensile strength, Young's modulus, flexural strength, flexural modulus, and impact strength properties of the composites were carried out. Moreover, the 50 wt% filler-loaded composites had optimum tensile strength, flexural strength, and flexural modulus, whereas the 35 wt% of filler loading case was the best regarding Young's modulus, flexural strength, flexural modulus, and impact strength. Furthermore, the scanning electron microscope results demonstrate that as filler loading increases, more voids and fiber pullout occur.     

Synthesis of arborescent polystyrene by “click” grafting

A method was developed for the synthesis of arborescent polystyrene by “click” coupling. Acetylene functionalities were introduced on linear polystyrene (M_n = 5300 g/mol, M_w/M_n = 1.05) by acetylation and reaction with potassium hydroxide, 18‐crown‐6 and propargyl bromide in toluene. Polymerization of styrene with 6‐tert‐butyldimethylsiloxyhexyllithium yielded polystyrene (M_n = 5200 g/mol, M_w/M_n = 1.09) with a protected hydroxyl chain end. Deprotection, followed by conversions to tosyl and azide functionalities, provided the side chain material. Coupling with CuBr and N,N,N′,N″,N″‐pentamethyldiethylenetriamine proceeded in up to 94% yield. Repetition of the grafting cycles led to well‐defined (M_w/M_n ≤ 1.1) polymers of generations G1 and G2 in 84% and 60% yield, respectively, with M_n and branching functionalities reaching 2.8 × 10⁶ g/mol and 460, respectively, for the G2 polymer. Coupling longer (M_n = 45,000 g/mol) side chains with acetylene‐functionalized substrates was also examined. For a linear substrate, a G0 polymer with M_n = 4.6 × 10⁵ g/mol and M_w/M_n = 1.10 was obtained in 87% yield; coupling with the G0 (M_n = 52,000 g/mol) substrate produced a G1 polymer (M_n = 1.4×10⁶ g/mol, M_w/M_n = 1.38) in 28% yield. The complementary approach using azide‐functionalized substrates and acetylene‐terminated side chains was also investigated, but proceeded in lower yield. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1730–1740     

Fluorometric sensing of DNA using curcumin encapsulated in nanoparticle-assembled microcapsules prepared from poly(diallylammonium chloride-co-sulfur dioxide)

We report on the synthesis of microcapsules (MCs) containing self-assembled nanoparticles formed from poly[diallylammonium chloride-co-(sulfur dioxide)] in the presence of citrate and silica sol nanoparticles. The MCs are spherical, and SEM and optical microscopy reveal them to have micrometer size. The fluorescent probe curcumin was encapsulated in the MCs and found to be located in the shell. The fluorescence of curcumin in the MCs is altered depending on their microenvironment. Effects of pH and ammonia on the fluorescence of curcumin in the MCs also were studied. The brightness of the probe in the MCs increases on addition of DNA. The effect was used to determine DNA from fish sperm by fluorometry. The association constant (K) is 4?000 mL.g^?1, and the number of binding sites is ~1.0.

Adhesion Dynamics on the Line: The Mass Aggregation Process

This paper studies several problems in adhesion dynamics on the real line. We consider an ensemble of particles with i.i.d. initial velocities. In the gravitational case, we identify a shock time and describe several aspects of the mass aggregation process before, at and after this time. We also study the long time behavior of the ballistic aggregation process.