A Study of the Association between Primary Oral Pathologies (Dental Caries and Periodontal Diseases) Using Synchrotron Molecular FTIR Spectroscopy in View of the Patient's Personalized Clinical Picture (Demographics and Anamnesis).

In this exploratory study, we searched for associations between the two most common diseases of the oral cavity-dental caries and periodontal diseases-taking into account additional factors, such as personalized clinical pictures (the individual risk factors of the patient), based on the method of a multivariate data analysis of the molecular changes in the composition of human gingival crevicular fluid (GCF). For this purpose, a set of synchrotron Fourier-transform infrared spectroscopy (FTIR) spectra of gingival crevicular fluid samples from patients with different demographics, levels of dental caries development and periodontal diseases, and the presence/absence of concomitant chronic diseases were obtained and analyzed. Using a set of techniques (v-, F-, Chi-square tests; a principal component analysis (PCA); and the hierarchical clustering of principal components (HCPCs)) implemented in the R package FactoMineR allowed us to assess the relationship between the principal components (PCs) and characteristics of the respondents. By identifying the features (vibrational modes in the FTIR spectra) that contribute most to the differentiation of the spectral dataset, and by taking into account the interrelationships between the patients' characteristics, we were able to match specific biological markers (specific molecular groups) to the two factors of interest-two types of oral pathologies. The results obtained show that the observed changes in the quantitative and qualitative composition of the modes in the infrared (IR) spectra of the GCF samples from patients with different dental caries developments and periodontal diseases present confirm the difficulty of identifying patient-specific spectral information. At the same time, different periodontal pathologies are more closely associated with other characteristics of the patients than the level of their caries development. The multivariate analysis performed on the spectral dataset indicates the need to take into account not only the co-occurrence of oral diseases, but also some other factors. The lack of this consideration (typical in lots of studies in this area) may lead to misinterpretations and consequently to a loss of data when searching for biological markers of certain oral diseases.

Oxidation of iron by giant impact and its implication on the formation of reduced atmosphere in the early Earth.

Giant impact-driven redox processes in the atmosphere and magma ocean played crucial roles in the evolution of Earth. However, because of the absence of rock records from that time, understanding these processes has proven challenging. Here, we present experimental results that simulate the giant impact-driven reactions between iron and volatiles (H2O and CO2) using x-ray free electron laser (XFEL) as fast heat pump and structural probe. Under XFEL pump, iron is oxidized to wüstite (FeO), while volatiles are reduced to H2 and CO. Furthermore, iron oxidation proceeds into formation of hydrides (γ-FeHx) and siderite (FeCO3), implying redox boundary near 300-km depth. Through quantitative analysis on reaction products, we estimate the volatile and FeO budgets in bulk silicate Earth, supporting the Theia hypothesis. Our findings shed light on the fast and short-lived process that led to reduced atmosphere, required for the emergence of prebiotic organic molecules in the early Earth.

Changes in Dental Biofilm Proteins' Secondary Structure in Groups of People with Different Cariogenic Situations in the Oral Cavity and Using Medications by Means of Synchrotron FTIR-Microspectroscopy.

This work unveils the idea that the cariogenic status of the oral cavity (the presence of active caries lesions) can be predicted via a lineshape analysis of the infrared spectral signatures of the secondary structure of proteins in dental biofilms. These spectral signatures that work as natural markers also show strong sensitivity to the application in patients of a so-called modulator-a medicinal agent (a pelleted mineral complex with calcium glycerophosphate). For the first time, according to our knowledge, in terms of deconvolution of the complete spectral profile of the amide I and amide II bands, significant intra- and intergroup differences were determined in the secondary structure of proteins in the dental biofilm of patients with a healthy oral cavity and with a carious pathology. This allowed to conduct a mathematical assessment of the spectral shifts in proteins' secondary structure in connection with the cariogenic situation in the oral cavity and with an external modulation. It was shown that only for the component parallel ß-strands in the amide profile of the biofilm, a statistically significant (p < 0.05) change in its percentage weight (composition) was registered in a cariogenic situation (presence of active caries lesions). Note that no significant differences were detected in a normal situation (control) and in the presence of a carious pathology before and after the application of the modulator. The change in the frequency and percentage weight of parallel ß-strands in the spectra of dental biofilms proved to be the result of the presence of cariogenic mutans streptococci in the film as well as of the products of their metabolism-glucan polymers. We foresee that the results presented here can inherently provide the basis for the infrared spectral diagnosis of changes (shifts) in the oral microbiome driven by the development of the carious process in the oral cavity as well as for the choice of optimal therapeutic treatments of caries based on microbiome-directed prevention measures.

Surface figure correction with roughness reduction using carbon-doped platinum film for high-precision X-ray mirror fabrication.

To obtain the surface shape of an X-ray mirror with high precision, a differential deposition method was used instead of a direct removal method. To modify the mirror surface shape using the differential deposition method, it is necessary to coat it with a thick film, and the co-deposition method is used to suppress the increase in surface roughness. The addition of C to the Pt thin film, which is often used as an X-ray optical thin film, resulted in lower surface roughness compared with that with the Pt coating alone, and the stress change according to the thin film thickness was evaluated. Differential deposition controls the speed of the substrate during coating based on continuous motion. The stage was controlled by calculating the dwell time through deconvolution calculations based on the accurate measurement of the unit coating distribution and target shape. We successfully fabricated an X-ray mirror with high precision. This study indicated that an X-ray mirror surface could be manufactured by modifying the surface shape at a micrometer level through the coating. Changing the shape of existing mirrors can not only result in the manufacture of high-precision X-ray mirrors but also improve their performance.

Near-field infrared nanoscopic study of EUV- and e-beam-exposed hydrogen silsesquioxane photoresist.

This article presents a technique of scattering-type scanning near-field optical microscopy (s-SNOM) based on scanning probe microscopy as a nanoscale-resolution chemical visualization technique of the structural changes in photoresist thin films. Chemical investigations were conducted in the nanometer regime by highly concentrated near-field infrared on the sharp apex of the metal-coated atomic force microscopy (AFM) tip. When s-SNOM was applied along with Fourier transform infrared spectroscopy to characterize the extreme UV- and electron-beam (e-beam)-exposed hydrogen silsesquioxane films, line and space patterns of half-pitch 100, 200, 300, and 500 nm could be successfully visualized prior to pattern development in the chemical solutions. The linewidth and line edge roughness values of the exposed domains obtained by s-SNOM were comparable to those extracted from the AFM and scanning electron microscopy images after development. The chemical analysis capabilities provided by s-SNOM provide new analytical opportunities that are not possible with traditional e-beam-based photoresist measurement, thus allowing information to be obtained without interference from non-photoreaction processes such as wet development.

Selective CO2 adsorption and bathochromic shift in a phosphocholine-based lipid and conjugated polymer assembly.

We assemble a film of a phosphocholine-based lipid and a crystalline conjugated polymer using hydrophobic interactions between the alkyl tails of the lipid and alkyl side chains of the polymer, and demonstrated its selective gas adsorption properties and the polymer's improved light absorption properties. We show that a strong attractive interaction between the polar lipid heads and CO2 was responsible for 6 times more CO2 being adsorbed onto the assembly than N2, and that with repeated CO2 adsorption and vacuuming procedures, the assembly structures of the lipid-polymer assembly were irreversibly changed, as demonstrated by in situ grazing-incidence X-ray diffraction during the gas adsorption and desorption. Despite the disruption of the lipid structure caused by adsorbed polar gas molecules on polar head groups, gas adsorption could promote orderly alkyl chain packing by inducing compressive strain, resulting in enhanced electron delocalization of conjugated backbones and bathochromic light absorption. The findings suggest that merging the structures of the crystalline functional polymer and lipid bilayer is a viable option for solar energy-converting systems that use conjugated polymers as a light harvester and the polar heads as CO2-capturing sites.

In-depth probing of thermally-driven phase separation behavior of lamella-forming PS-b-PMMA films by infrared nanoscopy.

A non-invasive, image-based analytic method utilizing scattering-type scanning near-field optical microscopy (s-SNOM) is suggested to evaluate the phase separation behavior of lamella-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymer films. Taking advantage of the penetrability of the tip-enhanced IR signal into the films, the spatio-spectral maps of each component are constructed. Subsequently, the effect of a sole and combinatorial applications of the self-assembly procedures, such as solvent vapor annealing (SVA) and/or thermal annealing (TA), on the spatial distribution of PS or PMMA components is quantitatively assessed in terms of the areal portions of the PS domain, PMMA domain, and the mixed zone that is adjacent to the domain border. Additionally, by statistically comparing the local concentration profiles, the chemical contrast between the domains turns out to be dependent upon the annealing procedures (namely, SVA and SVA + TA). This technique can pave the way to an uncomplicated but precise investigation of the polymer nanostructure-based thin film devices whose performances are critically governed by the spatial arrangement of the chemical elements.

Programmable Synthesis of Silver Wheels.

The synthesis of sandwich-shaped multinuclear silver complexes with planar penta- and tetranuclear wheel-shaped silver units and a central anion, [Agn(2-HPB)2(A-)](OTf-)n-1, nAgA, n = 4 or 5 and A- = OH- or F- or Cl-, is reported, along with complete spectroscopic and structural characterization. An NMR mechanistic study reveals that silver complexes were formed in the following order: 2Ag → 3AgH2O → 5AgOH → 4AgOH. The central hydroxides in 4AgOH and 5AgOH exhibit exotic physical properties due to the confined environment inside the complex. The size of these silver wheels can be tuned by changing the central anion or extracting/adding one silver atom. This study provides the facile way to synthesize discrete wheel-shaped multinuclear silver complexes and provides valuable insights into the dynamics of the self-assembly process.

A role for subducted albite in the water cycle and alkalinity of subduction fluids.

Albite is one of the major constituents in the crust. We report here that albite, when subjected to hydrous cold subduction conditions, undergoes hitherto unknown breakdown into hydrated smectite, moganite, and corundum, above 2.9 GPa and 290 °C or about 90 km depth conditions, followed by subsequent breakdown of smectite into jadeite above 4.3 GPa and 435 °C or near 135 km depth. Upon the hydration into smectite, the fluid volume of the system decreases by ~14 %, whereas it increases by ~8 % upon its dehydration into jadeite. Both the hydration and dehydration depths are correlated to increases in seismicity by 93 % and 104 %, respectively, along the South Mariana trench over the past 5 years. Moreover, the formation of smectite is accompanied by the release of OH- species, which would explain the formation of moganite and expected alkalinity of the subducting fluid. Thus, we shed new insights into the mechanism of water transport and related geochemical and geophysical activities in the contemporary global subduction system.

Preparation and Characterization of Transparent Polyimide⁻Silica Composite Films Using Polyimide with Carboxylic Acid Groups.

Polyimide (PI) composite films with thicknesses of approximately 100 µm were prepared via a sol⁻gel reaction of 3-aminopropyltrimethoxysilane (APTMS) with poly(amic acid) (PAA) composite solutions using a thermal imidization process. PAA was synthesized by a conventional condensation reaction of two diamines, 3,5-diaminobenzoic acid (DABA), which has a carboxylic acid side group, and 2,2'-bis(trifluoromethyl)benzidine (TFMB), with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) in N,N-dimethylacetamide (DMAc). The PAA⁻silica composite solutions were prepared by mixing PAA with carboxylic acid side groups and various amounts of APTMS in a sol⁻gel process in DMAc using hydrochloric acid as a catalyst. The obtained PI⁻silica composite films showed relatively good thermal stability, and the thermal stability increased with increasing APTMS content. The optical properties and in-plane coefficient of thermal expansion (CTE) values of the PI⁻silica composite films were investigated. The CTE of the PI⁻silica composite films changed from 52.0 to 42.1 ppm/°C as the initial content of APTMS varied. The haze values and yellowness indices of the composite films increased as a function of the APTMS content.

Studies on Chemical IR Images of Poly(hydroxybutyrate⁻co⁻hydroxyhexanoate)/Poly(ethylene glycol) Blends and Two-Dimensional Correlation Spectroscopy.

Biodegradable poly-[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoates] (PHBHx) have been widely studied for their applications in potentially replacing petroleum-based thermoplastics. In this study, the effect of the high molecular weight (Mn = 3400) poly(ethylene glycol) (PEG) blended in the films of PHBHx with different ratios of PEG was investigated using chemical FTIR imaging. Chemical IR images and FTIR spectra measured with increasing temperature revealed that PEG plays an important role in changing the kinetics of PHBHx crystallization. In addition, two-dimensional correlation spectra clearly showed that thermal properties of PHBHx/PEG blend film changed when the blending ratio of PHBHx/PEG were 60/40 and 50/50. Consequently, PEG leads to changes in the thermal behavior of PHBHx copolymers.

Investigation of phase separated polyimide blend films containing boron nitride using FTIR imaging.

Immiscible aromatic polyimide (PI) blend films and a PI blend film incorporated with thermally conductive boron nitride (BN) were prepared, and their phase separation behaviors were examined by optical microscopy and FTIR imaging. The 2,2'-bis(trifluoromethyl)benzidine (TFMB)-containing and 4,4'-thiodianiline (TDA)-containing aromatic PI blend films and a PI blend/BN composite film show two clearly separated regions; one region is the TFMB-rich phase, and the other region is the TDA-rich phase. The introduction of BN induces morphological changes in the immiscible aromatic PI blend film without altering the composition of either domain. In particular, the BN is selectively incorporated into the TDA-rich phase in this study.

Understanding the structural differences between spherical and rod-shaped human insulin nanoparticles produced by supercritical fluids precipitation.

In this study, the thermal denaturation mechanism and secondary structures of two types of human insulin nanoparticles produced by a process of solution-enhanced dispersion by supercritical fluids using dimethyl sulfoxide (DMSO) and ethanol (EtOH) solutions of insulin are investigated using spectroscopic approaches and molecular dynamics calculations. First, the temperature-dependent IR spectra of spherical and rod-shaped insulin nanoparticles prepared from DMSO and EtOH solution, respectively, are analyzed using principal component analysis (PCA) and 2D correlation spectroscopy to obtain a deeper understanding of the molecular structures and thermal behavior of the two insulin particle shapes. All-atom molecular dynamics (AAMD) calculations are performed to investigate the influence of the solvent molecules on the production of the insulin nanoparticles and to elucidate the geometric differences between the two types of nanoparticles. The results of the PCA, the 2D correlation spectroscopic analysis, and the AAMD calculations clearly reveal that the thermal denaturation mechanisms and the degrees of hydrogen bonding in the spherical and rod-shaped insulin nanoparticles are different. The polarity of the solvent might not alter the structure or function of the insulin produced, but the solvent polarity does influence the synthesis of different shapes of insulin nanoparticles.

Two strategies for the self-assembly of gold nanoparticles: Photoreaction and radical reaction.

Gold nanoparticles modified with a newly synthesized cinnamate moiety (CI-AuNPs) were prepared using the phase method. The cinnamate moiety, which is well known for its photoreactive properties, could be reacted by means of radical attack and UV irradiation. Crosslinking of this moiety by the two reactions causes aggregation of the CI-AuNPs, which demonstrates the feasibility of fabricating self-assembled spherical structures by means of chemical crosslinking of gold nanoparticles through two distinct mechanisms, namely, photocycloaddition and radical reaction upon addition of an initiator. Both methods yielded monodispersed spherical CI-AuNPs assemblies, and especially the radical-induced system showed the ability to construct linear-chain structures. Here, we suggest the preparation of gold nanoparticles modified with a simply synthesized photoreactive group and their self-assembly via two selective strategies (photoreaction and radical reaction). We expect that this study will contribute to the strategic fabrication of self-assembled nanostructures.

Two-dimensional correlation analysis study of the photo-induced molecular reorientations of photosensitive polyester film containing 1,4-phenylenediacryloyl units in the backbone.

The photochemical reaction and molecular reorientation of a novel photosensitive polyester, poly[oxy(4-n-butyl-3,5-benzoate)oxy-1,4-phenylenediacryloyl] (PPDA-C4BZ), which contains n-butyl side groups and 1,4-phenylenediacryloyl units (PDA chromophores) in the main chain, are reported in detail. We applied two-dimensional (2D) correlation analysis for the infrared (IR) and ultraviolet (UV) absorption spectra of nanoscaled films of PPDA-C4BZ to establish the sequence of the photo-induced segmental reorientations that result from UV irradiation. The photochemical reaction was found to have a greater effect on the polymer's main chains than on its side groups and to induce the reorientation of the polymer molecules. In particular, a cycloaddition process occurs first in the PDA chromophore units and then the local reorientation of the polymer molecules is induced. Namely, such photodimerization of the PDA chromophores induces the molecular reorientations of the PDA chromophores and the benzoate units in the main chain. The photo-induced molecular reorientations occur in the following sequence: photodimerization --> benzoate units --> PDA chromophores --> n-butyl side groups. In addition, a two-dimensional map of the first derivatives of the UV absorption spectra with respect to the exposure energy provided evidence of the formation of head-to-head aggregates (i.e., H-aggregates) of PPDA-C4BZ molecules.

UV-driven switching of chain orientation and liquid crystal alignment in nanoscale thin films of a novel polyimide bearing stilbene moieties in the backbone.

A novel photosensitive polyimide, poly(4,4'-stilbenylene 4,4'-oxidiphthalimide) (ODPA-Stilbene PSPI) was newly synthesized. The most surprising feature of this PSPI is that the PSPI films irradiated with linear polarized ultraviolet light (LPUVL) can favorably induce a unidirectional alignment of liquid crystals (LCs) in contact with the film surface and further switch the director of the unidirectionally aligned LCs from a perpendicular direction to a parallel direction with respect to the polarization direction of LPUVL by simply controlling the exposure dose in the irradiation process. These LPUVL-irradiated films were found to provide high anchoring energy to LCs, always giving very stable, homogeneous cells with unidirectionally aligned LCs regardless of the LC alignment directions. In the films, the PSPI polymer chains were found to undergo favorably unidirectional orientation via a specific orientation sequence of the polymer chain segments led by the directionally selective trans-cis photoisomerization of the stilbene chromophore units in the backbone induced by LPUVL exposure. Such unidirectionally oriented polymer chains of the films induce alignment of the LCs along the orientation direction of the polymer chains via favorable anisotropic molecular interactions between the oriented polymer chain segments and the LC molecules. In addition, the PSPI has an excellent film formation processibility; good quality PSPI thin films with a smooth surface are easily produced by simple spin-coating of the soluble poly(amic acid) precursor and subsequent thermal imidization process. In summary, this new PSPI is the promising LC alignment layer candidate with rubbing-free processing for the production of advanced LC display devices, including LC display televisions with large display areas.

Sequence of Rubbing-Induced Molecular Segmental Reorientations in the Nanoscale Film Surface of a Brush Polymer Rod.

Poly(p-phenylene-3,6-bis(4-(n-butoxy)phenyloxy)pyromellitimide) (C4-PMDA-PDA PI), a well-defined model brush polymer composed of a rodlike polymer backbone with two bristles per repeat unit, was the first reported polyimide to align liquid crystals perpendicular to the rubbing direction at the rubbed film surface. In the present study, we used polarized infrared (IR) spectroscopy and 2D correlation analyses of the resulting IR spectra to study nanoscale films of C4-PMDA-PDA PI rubbed at various rubbing densities. The results of these studies allowed us to establish the nature and sequence of the rubbing-induced segmental reorientations that occur in the polymer molecules at the film surface. The rubbing process was found to reorient the fully rodlike polymer backbones and the n-butyl bristle end groups such that they lay parallel to the rubbing direction. In contrast, rubbing caused the phenyloxy bristle units to reorient to a direction perpendicular to the rubbing direction. These reorientations of the polymer's main chain and bristles became more pronounced with increasing rubbing density, and the rubbing process had a greater effect on the polymer's main chains than on the bristles. The rubbing-induced reorientations of the polymer segments were found to follow the sequence PDA (phenyl ring), imide ring, phenyloxy unit, imide C-N bond, and n-butyl group. It was additionally evident that the rubbing process reorients the imide rings biaxially, that is, both along the rubbing direction and out of the plane. This biaxial reorientation was found to be accompanied by a biaxial reorientation of the bristles chemically bonded to the PMDA unit that includes the imide rings. In particular, increasing the rubbing density enhanced the out-of-plane reorientation of the imide rings. In contrast, no rubbing-induced inclination of the reoriented imide rings (i.e., the polymer's main chains) was detected.