ABSTRACT
OBJECTIVE: To identify changes in the microbiome of saliva and to compare it with the microbiome of the oropharynx of patients with migraine. MATERIAL AND METHODS: Sixty patients with migraine (21-56 years old), were examined using a headache diary, MIDAS and VAS. A microbiological examination of saliva and smear from the mucosa of the posterior wall of the oropharynx with evaluation by the method of mass spectrometry of microbial markers (MSMM) with the determination of 57 microorganisms was performed. All patients had comorbid chronic diseases of the gastrointestinal tract and upper respiratory tract (URT), according to anamnestic data and examination by specialists. RESULTS: A significant increase in the content of markers of resident (conditionally pathogenic) microorganisms characteristic of chronic diseases of URT (strepto- and staphylococci); markers of transient microorganisms characteristic of intestinal microflora (clostridia, gram-negative rods, anaerobes) that are normally absent; viral markers of cytomegaloviruses and herpes groups; a decrease in the content of fungi were identified in saliva. A comparative analysis of the microbiome of saliva and oropharynx showed: 1) a significant decrease in the concentration of coccal flora Enterococcus spp., Streptococcus mutans, Staphylococcus aureus, anaerobic bacteria Clostridium difficile and Clostridium perfringens in saliva; enterobacteria Helicobacter pylori; gram-negative rods Kingella spp., fungi and Epstein-Barr virus; 2) an increase in salivary concentrations of Staphylococcus epidermidis, anaerobic Clostridium ramosum and Fusobacterium spp./Haemophilus spp. and gram-negative bacilli Porphyromonas spp. CONCLUSION: A comparative assessment of the microbiota of a smear from the posterior wall of the oropharynx and saliva using MMSM showed the presence of dysbiosis both in the oropharynx and in the saliva of patients with migraine. However, there were fewer deviations from the norm in saliva, therefore, for diagnostic purposes, a smear from the posterior wall of the oropharynx is more significant as a biomarker for patients with migraine.
Subject(s)
Microbiota , Migraine Disorders , Oropharynx , Saliva , Humans , Saliva/microbiology , Adult , Female , Male , Middle Aged , Migraine Disorders/microbiology , Migraine Disorders/diagnosis , Oropharynx/microbiology , Young AdultABSTRACT
A novel stacking procedure is presented for volume phase holographic gratings (VPHGs) recorded in photopolymer material using Corning Willow Glass as a flexible substrate in order to achieve broader angular and spectral selectivity in a diffractive device with high efficiency for solar and LED applications. For the first time to our knowledge, we have shown a device designed for use with a white LED that has the same input and output angles and high efficiency when illuminated by different wavelengths. In this paper, two VPHGs were designed, experimentally recorded, and tested when illuminated at normal incidence. The experimental approach is based on stacking two individual gratings in which the spatial frequency and slant have been tailored to the target wavelength and using real-time on-Bragg monitoring of the gratings in order to control the recorded refractive index modulation, thereby optimizing each grating efficiency for its design wavelength. Lamination of the two gratings together was enabled by using a flexible glass substrate (Corning Willow Glass). Recording conditions were studied in order to minimize the change in diffraction efficiency and peak diffraction angle during lamination and bleaching. The final fabricated stacked device was illuminated by a white light source, and its output was spectrally analyzed. Compared to a single grating, the stacked device demonstrated a twofold increase in angular and wavelength range. The angular and wavelength selectivity curves are in good agreement with the theoretical prediction for this design. This approach could be used to fabricate stacked lenses for white light LED or solar applications.
ABSTRACT
The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modeling of the sensor response (i.e., change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using the Raman-Nath theory and Kogelnik's coupled wave theory. The influence of a range of parameters on the sensitivity of holographically recorded surface and volume photonic structures has been studied, namely, hologram geometry, hologram thickness and spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index. From this, the optimum fabrication conditions for both surface and volume holographic gas sensor designs have been identified. Here in Part II, results from modeling of the influence of design on the sensor response of holographically recorded volume grating structures for gas sensing applications are reported.
ABSTRACT
The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modeling of the sensor response (i.e., change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using Raman-Nath theory and Kogelnik's coupled wave theory. The influence of a range of parameters on the sensor response of holographically recorded surface and volume photonic grating structures has been studied, namely the phase difference between the diffracted and probe beam introduced by the grating, grating geometry, thickness, spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index. From this, the optimum fabrication conditions for both surface and volume holographic gas sensor designs have been identified. Here, in part I, results from theoretical modeling of the influence of design on the sensor response of holographically inscribed surface relief structures for gas sensing applications is reported.
ABSTRACT
A novel composition for a low-toxicity, water-soluble, holographic photopolymer capable of recording bright reflection gratings with diffraction efficiency of up to 50% is reported. The unique combination of two chemical components, namely, a chain transfer agent and a free radical scavenger, is reported to enhance the holographic recording ability of a diacetone acrylamide (DA)-based photopolymer in reflection mode by 3-fold. Characterization of the dependence of diffraction efficiency of the reflection gratings on spatial frequency, recording intensity, exposure energy, and recording wavelength has been carried out for the new low-toxicity material. The use of UV postexposure as a method of improving the stability of the photopolymer-based reflection holograms is reported. The ability of the modified DA photopolymer to record bright Denisyuk holograms which are viewable in different lighting conditions is demonstrated.
ABSTRACT
The patterning of an acrylamide-based photopolymer surface by holographic recording is studied. The patterns are induced by light alone and no post-processing is required. Periodic surface modulation is observed in addition to a volume phase grating. An investigation has been carried out using white light interferometry into the dependence of the amplitude of the photo induced surface relief modulation on the spatial frequency, intensity of recording and sample thickness. The observed dependencies indicate that the diffusion of material during the holographic recording plays a major role in surface relief formation. The possibility for inscription of surface relief patterns opens the door to at least two new applications for this photopolymer: fabrication of diffractive optical elements and biosensors.
