Demonstration of Confinement and Chiral Symmetry Breaking in SO(N_{c}) Gauge Theories.

We demonstrate that SO(N_{c}) gauge theories with matter fields in the vector representation confine due to monopole condensation and break the SU(N_{F}) chiral symmetry to SO(N_{F}) via the quark bilinear. Our results are obtained by perturbing the N=1 supersymmetric theory with anomaly-mediated supersymmetry breaking.

Early increase in blood supply (EIBS) is associated with tumor risk in the Azoxymethane model of colon cancer.

Background: The present study aimed to investigate the role of blood supply in early tumorigenesis in colorectal cancer. We leveraged the renin angiotensin system (RAS) to alter colonic blood supply and determine the effect on tumor initiation and progression.

Methods: To test the effect of blood supply on tumorigenesis, 53 male A/J mice were randomly assigned to one of three RAS modulation groups and one of two AOM treatments.

Skeletal light-scattering accelerates bleaching response in reef-building corals.

Background: At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation.

Polarization gating spectroscopy of normal-appearing duodenal mucosa to detect pancreatic cancer.

Background: According to the field effect theory, by detecting microvasculature changes such as early increase in blood supply (EIBS) in the surrounding tissue, neoplastic lesions can be identified from a distance.

Objective: To determine the feasibility and efficacy of a fiberoptic probe containing novel polarization gating spectroscopy technology to identify patients with pancreatic adenocarcinoma (PAC) by the field effect theory.

Design: Prospective cohort (pilot) study.

Monte Carlo model of the depolarization of backscattered linearly polarized light in the sub-diffusion regime.

We present a predictive model of the depolarization ratio of backscattered linearly polarized light from spatially continuous refractive index media that is applicable to the sub-diffusion regime of light scattering. Using Monte Carlo simulations, we derived a simple relationship between the depolarization ratio and both the sample optical properties and illumination-collection geometry. Our model was validated on tissue simulating phantoms and found to be in good agreement.

Method of detecting tissue contact for fiber-optic probes to automate data acquisition without hardware modification.

We present a novel algorithm to detect contact with tissue and automate data acquisition. Contact fiber-optic probe systems are useful in noninvasive applications and real-time analysis of tissue properties. However, applications of these technologies are limited to procedures with visualization to ensure probe-tissue contact and individual user techniques can introduce variability.

Algorithm for automated selection of application-specific fiber-optic reflectance probes.

Several optical techniques and fiber-optic probe systems have been designed to measure the optical properties of tissue. While a wide range of options is often beneficial, it poses a problem to investigators selecting which method to use for their biomedical application of interest. We present a methodology to optimally select a probe that matches the application requirements.

Analytical light reflectance models for overlapping illumination and collection area geometries.

Several biomedical applications, such as detection of dysplasia, require selective interrogation of superficial tissue structures less than a few hundred micrometers thick. Techniques and methods have been developed to limit the penetration depth of light in tissue, including the design of systems such as fiber-optic probes that have overlapping illumination and collection areas on the tissue surface. For such geometries, the diffusion approximation to the light-transport equation typically does not apply, and as a result there is no general model to extract tissue optical properties from reflectance measurements.

A fiber optic probe design to measure depth-limited optical properties in-vivo with low-coherence enhanced backscattering (LEBS) spectroscopy.

Low-coherence enhanced backscattering (LEBS) spectroscopy is an angular resolved backscattering technique that is sensitive to sub-diffusion light transport length scales in which information about scattering phase function is preserved. Our group has shown the ability to measure the spatial backscattering impulse response function along with depth-selective optical properties in tissue ex-vivo using LEBS. Here we report the design and implementation of a lens-free fiber optic LEBS probe capable of providing depth-limited measurements of the reduced scattering coefficient in-vivo.

Monte Carlo model of the penetration depth for polarization gating spectroscopy: influence of illumination-collection geometry and sample optical properties.

Polarization-gating has been widely used to probe superficial tissue structures, but the penetration depth properties of this method have not been completely elucidated. This study employs a polarization-sensitive Monte Carlo method to characterize the penetration depth statistics of polarization-gating. The analysis demonstrates that the penetration depth depends on both the illumination-collection geometry [illumination-collection area (R) and collection angle (θ(c))] and on the optical properties of the sample, which include the scattering coefficient (μ(s)), absorption coefficient (μ(a)), anisotropy factor (g), and the type of the phase function.

In vivo measurement of the shape of the tissue-refractive-index correlation function and its application to detection of colorectal field carcinogenesis.

Polarization-gated spectroscopy is an established method to depth-selectively interrogate the structural properties of biological tissue. We employ this method in vivo in the azoxymethane (AOM)-treated rat model to monitor the morphological changes that occur in the field of a tumor during early carcinogenesis. The results demonstrate a statistically significant change in the shape of the refractive-index correlation function for AOM-treated rats versus saline-treated controls.

Neo-angiogenesis and the premalignant micro-circulatory augmentation of early colon carcinogenesis.

Spectroscopic techniques have demonstrated that in the microscopically normal mucosa, there is an increase in mucosal micro-circulation in patients harboring neoplasia elsewhere in the colon (i.e. marker of field carcinogenesis).

Analysis of pressure, angle and temporal effects on tissue optical properties from polarization-gated spectroscopic probe measurements.

Noninvasive optical techniques for tissue characterization, in particular, light scattering properties and blood supply quantification of mucosa, is useful in a wide variety of applications. However, fiber-optic probes that require contact with the tissue surface can present a challenging problem in the variability of in vivo measurements due the nature of interactions, for example affects due to variations in pressure applied to the probe tip. We present an in vivo evaluation of pressure, angle, and temporal effects on tissue properties for polarization-gated spectroscopy at superficial depths (within 100 to 200 microns of tissue surface) for oral mucosa.

Optical measurement of rectal microvasculature as an adjunct to flexible sigmoidosocopy: gender-specific implications.

Flexible sigmoidoscopy is a robust, clinically validated, and widely available colorectal cancer screening technique that is currently sanctioned by major guideline organizations. Given that endoscopic visualization is generally limited to the distal third of the colon and women tend to have a proclivity for proximal lesions, the flexible sigmoidoscopy performance is markedly inferior in women than in men. Our group has shown that by using a novel light-scattering approach, we were able to detect an early increase in blood supply (EIBS) in the distal colonic mucosa, which served as a marker of field carcinogenesis and, hence, proximal neoplasia.

Association between rectal optical signatures and colonic neoplasia: potential applications for screening.

Field carcinogenesis detection represents a promising means for colorectal cancer (CRC) screening, although current techniques (e.g., flexible sigmoidoscopy) lack the requisite sensitivity.

Rectal mucosal microvascular blood supply increase is associated with colonic neoplasia.

Purpose: Endoscopic examination has proven effective in both detecting and preventing colorectal cancer; however, only about a quarter of eligible patients undergo screening. Even if the compliance rate increased, limited endoscopic capacity and cost would be prohibitive. There is a need for an accurate method to target colonoscopy to those most at risk of harboring colonic neoplasia.

Measuring mucosal blood supply in vivo with a polarization-gating probe.

There has been significant interest in developing depth-selective optical interrogation of biological tissue in general and of superficial (e.g., mucosal) tissue in particular.

Spectroscopic microvascular blood detection from the endoscopically normal colonic mucosa: biomarker for neoplasia risk.

Background & Aims: We previously used a novel biomedical optics technology, 4-dimensional elastically scattered light fingerprinting, to show that in experimental colon carcinogenesis the predysplastic epithelial microvascular blood content is increased markedly. To assess the potential clinical translatability of this putative field effect marker, we characterized the early increase in blood supply (EIBS) in human beings in vivo.

Methods: We developed a novel, endoscopically compatible, polarization-gated, spectroscopic probe that was capable of measuring oxygenated and deoxygenated (Dhb) hemoglobin specifically in the mucosal microcirculation through polarization gating.