We hypothesize that the capsular optical properties and thickness combined affect how accurate the diffuse reflectance on the surface of a capsular solid organ represents that on the subcapsular parenchyma. Monte Carlo simulations on two-layer geometries evaluated how a thin superficial layer with the thickness from 10 to 1000  μm affected the surface diffuse reflectance over a source–detector separation spanning 0.01 to 10 mm. The simulations represented the superficial layer presenting various contrasts concerning refractive index, anisotropy factor, absorption coefficient, and reduced scattering coefficient, versus those of the subsurface main medium. An analytical approach modeled the effects of the superficial layer of various thicknesses and optical properties on diffuse reflectance. Diffuse reflectance spectroscopy was performed ex vivo on 10 fresh human livers and 9 fresh human kidneys using a surface probe with a 3-mm source–detector separation. The difference of the device-specific diffuse reflectance on the organ between with the capsule and without the capsule has significantly greater spectral variation in the kidney than in the liver. The significantly greater spectral deviation of surface diffuse reflectance between with and without the capsule in the kidney than in the liver was analytically accountable by considering the much thicker capsule of the kidney than of the liver.

Microscopy with ultraviolet surface excitation (MUSE) is investigated as a means to enhance curricula and education in the life sciences based on simplicity of use, the incorporation of inexpensive hardware, and the simplest methods of tissue preparation. Ultraviolet excitation in effect replaces tissue sectioning because it penetrates only a few micrometers below the tissue surface at the single cell level, preventing the generation of out-of-focus light. Although tissue autofluorescence may be used, image quality and content can be enhanced by a brief immersion in a solution of nontoxic fluorescent dyes that selectively highlight different cellular compartments. Safe mixed-dye powder combinations have been developed to provide students who have minimal lab proficiencies with a one-step tissue staining process for rapid tissue preparation.

In linear-array transducer-based photoacoustic (PA) imaging, B-scan PA images are formed using the raw channel PA signals. Delay-and-sum (DAS) is the most prevalent algorithm due to its simple implementation, but it leads to low-quality images. Delay-multiply-and-sum (DMAS) provides a higher image quality in comparison with DAS while it imposes a computational burden of O  (  M2  )  . We introduce a nonlinear (NL) beamformer for linear-array PA imaging, which uses the p’th root of the detected signals and imposes the complexity of DAS [O  (  M  )  ]. The proposed algorithm is evaluated numerically and experimentally [wire-target and in-vivo sentinel lymph node (SLN) imaging], and the effects of the parameter p are investigated. The results show that the NL algorithm, using a root of p (NL_p), leads to lower sidelobes and higher signal-to-noise ratio compared with DAS and DMAS, for (p  >  2). The sidelobes level (for the wire-target phantom), at the depth of 11.4 mm, are about −31, −52, −52, −67, −88, and −109  dB, for DAS, DMAS, NL_2, NL_3, NL_4, and NL_5, respectively, indicating the superiority of the NL_p algorithm. In addition, the best value of p for SLN imaging is reported to be 12.

Annually, about 15 million preterm infants are born in the world. Of these, due to complications resulting from their premature birth, about 1 million would die before the age of five. Since the high incidence of preterm birth (PTB) is partially due to the lack of effective diagnostic modalities, methodologies are needed to determine risk of PTB. We propose a noninvasive tool based on polarized light imaging aimed at measuring the organization of collagen in the cervix. Cervical collagen has been shown to remodel with the approach of parturition. We used a full-field Mueller matrix polarimetric colposcope to assess and compare cervical collagen content and structure in nonpregnant and pregnant women in vivo. Local collagen directional azimuth was used and a total of eight cervices were imaged.