Localization of persistent Enterocytozoon bieneusi infection in normal rhesus macaques (Macaca mulatta) to the hepatobiliary tree

Enterocytozoon bieneusi is the most common microsporidian parasite recognized in human patients with AIDS. Recently, we identified a virtually identical organism causing a spontaneous infection associated with hepatobiliary and intestinal disease in simian immunodeficiency virus (SIV)-infected macaques. To examine the natural history of the infection, we examined captive rhesus macaques for E. bieneusi by PCR, in situ hybridization, and cytochemical techniques. PCR performed on fecal DNA detected enterocytozoon infection in 22 (16.7%) of 131 normal rhesus macaques (Macaca mulatta), compared to 18 (33.8%) of 53 rhesus macaques experimentally inoculated with SIV. In normal rhesus macaques, persistence of infection was demonstrated for up to 262 days and was usually not associated with clinical signs. In six of seven normal rhesus animals, E. bieneusi was detected by PCR in bile obtained through percutaneous cholecystocentesis but not by in situ hybridization performed on endoscopic biopsies of duodenum and proximal jejunum.     

Amorphous aluminum alloys—synthesis and stability

Recent innovations in metallic glasses have led to new alloy classes that may be vitrified and a re-examination of the key alloying factors influencing glass formation and stability. The new alloy classes are usually at least ternary systems and often higher order that can be grouped into two general categories. In one case, large, bulk volumes may be slowly cooled to the glassy state, which signifies a nucleation controlled synthesis. The other important class is represented by aluminum- and iron-based glasses that can be synthesized by rapid solidification processes such as melt spinning. These glasses are often called marginal glass formers that are synthesized under growth-controlled kinetic conditions. Glasses in both alloy classes can also be synthesized by intense deformation of crystalline multilayer arrays. These developments represent a major level of microstructure control that has an impact on the structural performance and stability.     

A fully automated optimization algorithm for determining the 3-D patient contour from photo-peak projection data in SPECT

The class of noninverse problems versus inverse problems is discussed. A general optimization approach to solving certain constrained noninverse problems is presented. This approach is applied in the area of single photon emission computed tomography to estimate the patient outer contour directly from the photo-peak projection data. The resulting algorithm is fully automated, fast, and the determined 3-D patient contour satisfies smoothness constraints. The accuracy and reliability of the algorithm is evaluated through Monte Carlo simulations, patient studies, and an experimental validation study.     

Rapid multiexcitation fluorescence spectroscopy system for in vivo tissue diagnosis

We have designed, fabricated, and tested a compact, transportable, excitation-emission spectrofluorimeter with optical-fiber light delivery and collection for use in rapid analysis of tissues in a clinical setting. This system provides up to eleven different excitation wavelengths, permitting collection of all the corresponding emission spectra in approximately 600 ms. It uses a N(2) laser that pumps a sequence of dyes placed in cuvettes on a rotating wheel. A white-light excitation source permits acquisition of the tissue's diffuse reflectance spectrum on each cycle. Return fluorescence and reflected light are dispersed by a small spectrograph and detected by a photodiode-array detector. The system can collect a single-shot spectrum from biological tissue with a signal-to-noise ratio in excess of 50:1.     

Polarization microscopy as a tool for quantitative evaluation of collagen using picrosirius red in different stages of CKD in cats

Chronic kidney disease (CKD) is a relevant disease in feline clinic. The tubulointerstitial damage, with collagen deposition and fibrosis, is an important result of this process. The aim of this study was to quantify and correlate the deposition of collagen and severity of interstitial fibrosis (IF) in the kidney from cats in different stages of CKD. Kidney fragments from 10 adult cats with CKD were analyzed and stained by Masson's trichrome (MT) and Picrosirius red (PSR) for circular polarized microscopy. Random quantitative analysis was performed on MT sections to classify the degree of IF, per field area, with and without circular polarization. Statistics correlations were performed by Spearman's (ρ; p < .05). There was a significant correlation of IF quantification with the area of interstitial collagen deposition by polarized PSR (PSRp) (r = .7939, p = .0098) and nonpolarized PSR (PSRn) (r = .7781, p = .0080). There was a positive correlation of serum creatinine (sCr) at different stages of CKD with PSRp (r = .7939, p = .0098), PSRn (r = .8667, p = .0027) and MT (r = .7818, p = .0117). Correlations between the percentage of quantified area was also positive from PSRp to PSRn (r = .9030, p = .0009) and PSRp to MT (r = .7939, p = .0098). The PSRN was also correlated with MT (r = .9273, p = .0001). The correlation with IF and sCr follows the disease evolution and the quantification of collagen by PSR is an excellent tool for analyzing the disease severity at different stages.     

Use of sorbyl chloride–osmium staining for fibrillar measurements in cotton fibers

The technique for staining unsaturated additives within cotton fibers reacts osmium tetroxide with a sorbyl moiety which has been attached to the cellulose chain. Resulting electron micrographs indicate that contrast is considerably enhanced. Measurements of fibrillar size averaged 0.30 nm, closely approximating the values in the literature.     

Peeling Meshed Potatoes

We study variants of the potato peeling problem on meshed (triangulated) polygons. Given a polygon with holes, and a triangular mesh that covers its interior (possibly using additional vertices), we want to find a largest-area connected set of triangles of the mesh that is convex, or has some other shape-related property. In particular, we consider (i) convexity, (ii) monotonicity, (iii) bounded backturn, and (iv) bounded total turning angle. The first three problems are solved in polynomial time, whereas the fourth problem is shown to be NP-hard.