The Stokes shift spectra (S3) of human cancerous and normal prostate tissues were collected label free at a selected wavelength interval of 40 nm to investigate the efficacy of the approach based on three key molecules-tryptophan, collagen, and reduced nicotinamide adenine dinucleotide (NADH)-as cancer biomarkers. S3 combines both fluorescence and absorption spectra in one scan. The S3 spectra were analyzed using machine learning (ML) algorithms, including principal component analysis (PCA), nonnegative matrix factorization (NMF), and support vector machines (SVMs). The components retrieved from the S3 spectra were considered principal biomarkers. The differences in the weights of the components between the two types of tissues were found to be significant. Sensitivity, specificity, and accuracy were calculated to evaluate the performance of SVM classification. This research demonstrates that S3 spectroscopy is effective for detecting the changes in the relative concentrations of the endogenous fluorophores in tissues due to the development of cancer label free.

We report on the use of label-free, native fluorescence (NFL) spectroscopy and machine learning (ML) algorithms to study the correlation of relative tryptophan levels with prostate cancer aggressiveness. Three extensively studied prostate cancer cell lines were used; PC3, an aggressive, androgen-resistant line, with a high tendency to metastasize in vivo, DU-145, a less aggressive cancer cell line, also androgen-resistant, and LNCaP, an androgen sensitive line, which has a low tendency to metastasize. Using an excitation of 300 nm, differences in the NFL spectral profiles from these cell lines were found to correlate with changes in the relative concentrations of tryptophan and reduced nicotinamide adenine dinucleotide (NADH). The use of ML may present a powerful tool for the assessment of the likelihood of a cancer to metastasize. This technique could aid in the decision whether to use highly aggressive adjuvant chemotherapy or radiation therapy after surgical resection of a prostate cancer.

Early detection of prostate cancer is critical for the success of cancer therapy. It is believed that the biochemical changes that cause the optical spectra changes would appear earlier than the histological aberration. The aim of this ex vivo study was to evaluate the ability of Stokes Shift Spectra (S3) to identify human prostate cancerous tissues from the normal. Fifteen (15) pairs of with pathologically confirmed human prostate cancerous and normal tissues underwent Stokes Shift Spectra measurements with selective wavelength interval of 40 nm. The spectra were then analyzed using machine learning (ML) algorithms to classify the two types of tissues. The ML algorithms including principal component analysis (PCA) and nonnegative matrix factorization (NMF) were used for dimension reduction and feature detection. The characteristic component spectra were used to identify the key fluorophores related to carcinogenesis. The results show that these key fluorophores within tissue, e.g., tryptophan, collagen, and NADH, have different relative concentrations between cancerous and normal tissues. A multi-class classification was performed using support vector machines (SVMs). A leave-one- out cross validation was used to evaluate the performance of the classification with the gold standard histopathological results as the ground truth. The results with high sensitivity and specificity indicate that the S3 method is effective for detecting changes of fluorophore composition in human prostate tissues due to the development of cancer.

This chapter focuses on the biological applications of optical-resolution photoacoustic microscopy (OR-PAM) system in brain in vivo label-free imaging. The OR-PAM system is mainly composed of photoacoustic (PA) imaging system and laser source. The solid-state nanosecond laser is widely used as the pumping source to generate efficient signal for PA effect. The application of OR-PAM system is presented to monitor the vascular disrupting agent (VDA) therapeutic effect of glioma tumor. This work illustrates the aspects of contrast agent–free, high spatial resolution and brain vascular imaging for OR-PAM in small animal model.

A model is developed to calculate the optimal pump position for end-pump configuration. The 808 nm wing pump is employed to spread the absorption inside the crystal. By the optimal laser cavity design, a high-energy high-efficiency Nd:YLF laser operating at 1053 nm is presented. In cw operation, a 13.6 W power is obtained with a slope efficiency of 51% with respect to 30 W incident pump power. The beam quality is near diffraction limited with M-2 similar to 1.02. In Q-switch operation, a pulse energy of 5 mJ is achieved with a peak power of 125 kW at 1 kHz repetition rate. (C) 2017 Elsevier B.V. All rights reserved.

We have used synchrotron X-ray reflectivity measurements to investigate the structure of n-dotriacontane (n-C(32)H(66) or C32) films deposited from the vapor phase onto a SiO(2)-coated Si(100) surface. Our primary motivation was to determine whether the structure and growth mode of these films differ from those deposited from solution on the same substrate. The vapor-deposited films had a thickness of approximately 50 A thick as monitored in situ by high-resolution ellipsometry and were stable in air. Similar to the case of solution-deposited C32 films, we find that film growth in vacuum begins with a nearly complete bilayer adjacent to the SiO(2) surface formed by C32 molecules aligned with their long axis parallel to the interface followed by one or more partial layers of perpendicular molecules. These molecular layers coexist with bulk particles at higher coverages. Furthermore, after thermally cycling our vapor-deposited samples at atmospheric pressure above the bulk C32 melting point, we find the structure of our films as a function of temperature to be consistent with a phase diagram inferred previously for similarly treated solution-deposited films. Our results resolve some of the discrepancies that Basu and Satija (Basu, S.; Satija, S. K. Langmuir 2007, 23, 8331) found between the structure of vapor-deposited and solution-deposited films of intermediate-length alkanes at room temperature.

We report a magnetic x-ray scattering study of the field-induced multiferroic GdFe3(BO3)(4). Resonant x-ray magnetic scattering at the Gd L-II,L-III edges indicates that the Gd moments order at T-N approximate to 37 K. The magnetic structure is incommensurate below T-N, with the incommensurability decreasing monotonically with decreasing temperature until a transition to a commensurate magnetic phase is observed at T approximate to 10 K. Both the Gd and Fe moments undergo a spin reorientation transition at T-SR approximate to 9 K such that the moments are oriented along the crystallographic c axis at low temperatures. With magnetic field applied along the a axis, our measurements suggest that the field-induced polarization phase has a commensurate magnetic structure with Gd moments rotated similar to 45 degrees toward the basal plane, which is similar to the magnetic structure of the Gd subsystem observed in zero field between 9 and 10 K, and the Fe subsystem has a ferromagnetic component in the basal plane.

The temperature dependence of the density oscillations (layers) at the free surface of tetrakis(2-ethylhexoxy)silane, a nonmetallic molecular liquid, was investigated using x-ray reflectivity. Below similar to 215 K, the layer parameters weakly vary with temperature, if at all. Above this temperature, the layer spacings and intrinsic layer widths increase continuously, until there is no identifiable layering above 230 K. This transition occurs at T/T-c approximate to 0.23, a temperature region that is usually accessible in metallic liquids but is preempted by freezing in many dielectric liquids.

Oriented inorganic films can be grown under Langmuir monolayers floating on supersaturated aqueous solutions. This process mimics biomineralization, and is potentially an easy method for growing designed inorganic films. Grazing-incidence X-ray diffraction (in situ) and scanning electron microscopy (of films transferred to substrates) reveal that oriented growth occurs via two distinct mechanisms. First, there can be epitaxial growth, with organic and inorganic lattices relaxing to allow an exact match. A variant is the appearance of a reconstructed surface superlattice that mediates between the unstrained organic and bulk inorganic structures. Second, the alignment of crystals already formed can be enhanced via spontaneous self-aggregation into oriented chains.

Synchrotron X-ray reflectivity (XRR) confirms the formation of a quasi-immobilized layer in thin films of polydimethylsiloxane (PDMS) melts near silica surfaces. This layer (40-60A) has a lower density than the bulk value, and its thickness varies slightly with PDMS molecular weight. Formation of this layer is very rapid for PDMS melts with low molecular weights (below entanglement limit for these molecules) but takes 5-10 hours for higher molecular weights (close to and above their entanglement value).

Using X-ray reflectivity, we observe drastic differences in the interfacial structure and molecular ordering of diphenylsiloxane-dimethylsiloxane copolymer thin films deposited on hydroxylated versus H-terminated (etched) silicon wafers. We find that substrate type and comonomer ratio determine the conformational arrangements in these liquid films. High-energy bonding between the substrate and the molecules and an increase in rigidity of the molecules due to replacement of methyl groups by phenyl groups leads to a specific molecular ordering at the liquid/solid interface and pronounced density oscillations in this region. The observed structural reorganizations are explained by the interplay and the established balance between the chain flexibility and the polymer-substrate interactions.

Oscillatory density profiles (layers) have previously been observed at the free surfaces of liquid metals but not in other isotropic liquids. We have used x-ray reflectivity to study a molecular liquid, tetrakis(2-ethylhexoxy)silane. When cooled to T/Tc approximately 0.25 (well above the freezing point for this liquid), density oscillations appear at the surface. Lateral order within the layers is liquidlike. Our results confirm theoretical predictions that a surface-layered state will appear even in dielectric liquids at sufficiently low temperatures, if not preempted by freezing.

X-ray studies performed during the growth of CdCO3 and MnCO3 crystals from supersaturated aqueous solutions, at fatty acid monolayer templates, reveal that the nucleates are nearly three-dimensional powders below a threshold supersaturation. However, at higher supersaturations, the crystals are preferentially oriented with the {0 1 2} direction vertical. Scanning electron microscope images of samples transferred to substrates show discrete crystals at low concentrations, while at higher concentrations the crystals self-aggregate to form linear chains and sheets. The authors speculate that preferential alignment at the organic-inorganic interface is enhanced as a consequence of oriented aggregation of crystals. The role of monolayer-ion interactions in governing the morphologies and the resulting orientation of the inorganic nucleate is discussed.

X-ray reflectivity is used to study the interfacial structure of liquid squalane on SiO2/Si(100) substrates. The data show that there are density oscillations (‘layers’) near the interface, with the squalane molecular long axes parallel to the substrate. The results are compared to those from molecular dynamics simulations and recent force measurements.

The Compton profiles of Polycrystalline graphite and nanometeric graphite produced by mill grinding were measured and the Compton profile of polycrystalline graphite was calculated. The theoretical and the experimental Compton profiles of polycrystalline graphite, the experimental Compton profiles of nanometeric graphite were compared.

Compton scattering of gamma-rays, XRD, TEM and Raman scattering were used to investigate the nanocrystalline graphite produced by mill grinding. The graphite ground for 4 and 8 hours has a typical nanostructure. Further grinding produces a mixture of nanocrystalline and amorphous phases. Compared with the polycrystalline graphite, the electron momentum distribution probability (EMD) of nanocrystalline graphite is a little higher in the low momentum range. We attribute such a change mainly to the high interface ratio of nanograined graphite.