Interlacing multiplexing techniques for optical morphological correlation

We propose a novel approach to implement nonlinear morphological correlation. Previous implementation was based on a time sequential approach that consists on displaying different binary image decomposition in a joint transform correlator adding each joint power spectra sequentially. A second Fourier transformation of the sum of joint power spectra gives the correlation output. In this paper, we propose to interlace the different binary images into one single distribution. Then, we introduce the distribution in a conventional joint transform correlator. The correlation output gives the morphological correlation at a specific location. The advantage is important considering that no sequential approach is needed anymore, so the necessary number of correlations is reduced. Optical implementation results are provided.     

Direct laser light enhancement of susceptibility of bacteria to gentamicin antibiotic

Objectives

To test the effect of pulsed (Q-switched) and continuous wave (CW) laser light at wavelength of 532 nm on the viability of free-living stationary phase bacteria with and without gentamicin (an antibiotic) treatment.

Methods

Free living stationary phase gram negative bacteria (Pseudomonas aeruginosa strain PAO1) was immersed in Luria Broth (LB) solution and exposed to Q-switched and CW lasers with and without the addition of the antibiotic gentamicin. Cell viability was determined at different time points.

Results

Laser treatment alone did not reduce cell viability compared to untreated control and the gentamicin treatment alone only resulted in a 0.5 log reduction in the viable count for P. aeruginosa. The combined laser and gentamicin treatment, however, resulted in a synergistic effect and viability was reduced by 8 logs for P. aeruginosa PAO1.

Conclusions

Combination of laser light with gentamicin shows an improved efficacy against P. aeruginosa.     

Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array

We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.     

The structure of the smectic phases of terephthal-bis-(butylaniline) studied by electron spin resonance spectroscopy

Electron spin resonance (E.S.R.) measurements at X-band (3·3 kG) of the spin probe 17β-hydroxy-4,4′-dimethylspiro[5α-androstane-3,2′-oxazolidin]-3′-yloxyl dissolved in the smectic phases (A, C and B) of the mesogen 4,4′-terephthal-bis(butylaniline) (TBBA) are reported. Two types of samples were studied in the dependence on temperature, sample orientation and strength of the magnetic field: (i) glass plate sandwiches with less than 0·1 mm of the mesogen, and (ii) 4 mm i.d. cylindrical glass tube. The sandwich samples were prepared as monodomains with the smectic layers parallel to the glass plates. In these samples the orientation of the layers and of the director is fixed and cannot be reoriented even in a magnetic field of 21 kG. From the angular dependence of the spectrum, the tilt angle, the order parameter and their temperature dependence were determined.

In the cylindrical samples the original orientation of the smectic layers is preserved, and up to about 3 kG the director's orientation with respect to the sample is almost unaffected in all smectic phases. On subjecting the sample to higher fields (～ 20 kG) the director in the smectic C phase will re-align so as to minimize the magnetic energy, subject to the fixed tilt angle. The new alignment is preserved when the strength of the magnetic field is reduced. No such re-alignment is observed in the smectic B phase even after subjecting the sample to a field of 21 kG, in contrast to previous deuterium N.M.R. measurements at 14 kG. It is suggested that in this phase the director is pulled by strong fields but relaxes to its original direction when the magnetic field is brought back to 3·3 kG.     

Micro- and nano-spheres of low melting point metals and alloys,formed by ultrasonic cavitation

Metals and alloys of low melting points (<430 °C) can be melted in hot silicone oil to form two immiscible liquids. Irradiation of the system with ultrasonic energy induces acoustic cavitation in the oil, which disperses the molten metals into microspheres that solidify rapidly upon cooling. This method has been applied to seven pure metals (Ga, In, Sn, Bi, Pb, Zn, Hg) and two eutectic alloys of gold (Au–Ge and Au–Si). The morphology and composition of the resulting microspheres were examined by SEM and EDS. Eutectic Au–Si formed also crystalline Au nanoparticles, which were separated and studied by HRTEM.     

Structural analysis of complex saponins of Balanites aegyptiaca by 800 MHz 1H NMR spectroscopy

The main saponin (1) present in the mesocarp of Balanites aegyptiaca fruit is a mixture of 22R and 22S epimers of 26-(O-beta-D-glucopyranosyl)-3-beta-[4-O-(beta-D-glucopyranosyl)-2-O-(alpha-L-rhamnopyranosyl)-beta-D-glucopyranosyloxy]-22,26-dihydroxyfurost-5-ene. This structure differs from a previously reported saponin isolated from this source by the site of attachment of the rhamnosyl residue, and presumably represents a structural revision of the latter. The main saponin (2) present in the kernel is a xylopyranosyl derivative of 1. The use of high-field NMR enabled the practically complete assignment of 1H and 13C chemical shifts of these complex saponins, existing as a mixture of C-22 epimers. Moreover, the work represents a new approach to structural elucidation of saponins: direct preparative-scale HPLC-RID of crude extracts followed by high-field NMR investigations supported by ESI-MSn.     

Passive and temporally continuous optical spectral analyzer of RF signals via wavelength coding

A novel approach realizing an optical spectrum analyzer for photonic detection of an unknown RF carrier signals is presented. The described module may be part of an electronic warfare system in which detection of a narrow band RF signal is required. Moreover, The RF signal is characterized by an unknown time varying carrier frequency embedded in wide band noise. The system uses a passive, fiber based photonic configuration. It allows the spectrum mapping of an incoming electronic RF signal modulated on an optical carrier. The spectral analyzer configuration uses a finite impulse response (FIR) filter that is realized by two different optical paths of parallel fibers which generate a spectral notch filter. Hence, a wavelength coding is realized by chromatic dispersion such that each wavelength is filtered by a different FIR filter. Therefore, the energy at a WDM demux output channels is actually proportional to the spectrum of the input RF signal. This spectral mapping is obtained without lose of temporal RF information.     

The chemistry of polycyclic arene imines. I. Substitution at the nitrogen atom of 1a,9b-dihydro-1H-phenanthro[9,10-b]azirine

Chlorides of carboxylic, sulfonic and phosphoric acids proved to convert phenanthrene-9,10-imine into the corresponding rearranged acet- sulfon- and phosphonamidophenanthrene. Trimethylchlorosilane and N,O-bis(trimethylsilyl)acetamide reacted with the imine without destruction of the aziridine ring. The silylated compound could be transferred into the respective N-substituted phenanthrene-9,10-imines when treated with acetyl-, methanesulfonyl-, 4-tosyl- and diethylphosphoryl chloride. A remarkably stable N-chlorophenanthrene-9,10-imine was obtained from the unsubstituted compound and N-chlorosuccinimide.