Effects of changing spatial scale on acoustic observations of patchiness in the Gulf Stream

We examine the influence of spatial scale on studies of nektonic patchiness at the north edge of the Gulf Stream by altering the grain size of acoustic cross sections and applying a patch-finding algorithm. From original pictures of 180 pixels deep by 540–1260 pixels long, we averaged depth and length, to give 9 scales ranging from fine grain (1 m vertical × 25 m horizontal sized pixels) to coarse grain (12 m × 300 m sized pixels). Measures of overall echo intensity within patches were the most predictable and showed little change with scale. Measures of variability of the echo within patches showed simple negative trends with scale and were best measured at fine spatial scales. Patch size and shape related variables have a more complex relationship with scale with differences between day and night transects more pronounced at intermediate scales. This suggests behavioral patch forming mechanisms within the nekton occur at a specific grain size (4 m vertical × 100 m horizontal) within the Gulf Stream front.     

Population-based study of fecal shedding of Clostridium perfringens in broodmares and foals

OBJECTIVE: To determine the percentage of broodmares and foals that shed Clostridium perfringens in their feces and classify the genotypes of those isolates. DESIGN: Prospective cross-sectional study. ANIMALS: 128 broodmares and their foals on 6 equine premises. PROCEDURES: Anaerobic and aerobic bacteriologic cultures were performed on feces collected 3 times from broodmares and foals. All isolates of C. perfringens were genotyped. RESULTS: Clostridium perfringens was isolated from the feces of 90% of 3-day-old foals and 64% of foals at 8 to 12 hours of age. A lower percentage of broodmares and 1- to 2-month-old foals shed C. perfringens in their feces, compared with neonatal foals. Among samples with positive results, C. perfringens type A was the most common genotype identified (85%); C. perfringens type A with the beta2 toxin gene was identified in 12% of samples, C. perfringens type A with the enterotoxin gene was identified in 2.1% of samples, and C. perfringens type C was identified in < 1% of samples. CONCLUSIONS AND CLINICAL RELEVANCE: Clostridium perfringens was identified from the feces of all but 6 foals by 3 days of age and is likely part of the normal microflora of neonatal foals. Most isolates from broodmares and foals are C. perfringens type A; thus, the clinical relevance of culture results alone is questionable. Clostridium perfringens type C, which has been associated with neonatal enterocolitis, is rarely found in the feces of horses.     

Analysis of anthocyanins in rat intestinal contents--impact of anthocyanin chemical structure on fecal excretion

Absorption of dietary anthocyanins is limited; however, fecal anthocyanin excretion has been rarely studied. We developed a method for extraction and analysis of fecal anthocyanins. Aqueous methanol (60%) maximized extraction efficiency (approximately 88%). Severe anthocyanin degradation (monitored by high-performance liquid chromatography) was observed in feces stored at -18 degrees C; therefore, storage time should be minimized and lower temperatures used. Fecal and cecal content samples were collected from 32 rats receiving either chokeberry, bilberry, grape-enriched (3.85 g monomeric anthocyanin per kg diet), or control diet for 14 weeks. Fecal anthocyanin concentrations were significantly different among groups (0.7/1.8/2.0 g/kg wet feces, chokeberry/bilberry/grape). Anthocyanin profiles of cecal contents and feces were similar. Losses in the intestinal contents were high for anthocyanin glucosides, moderate for galactosides, and negligible for arabinosides or xylosides. Acylation or diglucosylation enhanced anthocyanin stability. High anthocyanin concentration in the fecal content may favor anthocyanin absorption into the colon epithelial cells, resulting in potential health benefits.     

Formation of Chiral Interdigitated Multilayers at the Air-Liquid Interface Through Acid-Base Interactions

Thin interdigitated films composed of a long-chain, water-insoluble chiral acid (p-pentadecylmandelic acid of absolute configuration R) and a water-soluble chiral base (phenylethylamine, R') were constructed at the air-solution interface. The (R, R') structure was characterized to near-atomic resolution by grazing-incidence x-ray diffraction (GIXD). The two diastereomeric systems, (R, R') and (R, S'), demonstrate similar surface pressure-molecular area isotherms, but their structures are completely different on the molecular level, as monitored by GIXD. Complementary data on these two architectures were provided by atomic force microscopy.     

Prevention of organ allograft rejection by a specific Janus kinase 3 inhibitor

Because of its requirement for signaling by multiple cytokines, Janus kinase 3 (JAK3) is an excellent target for clinical immunosuppression. We report the development of a specific, orally active inhibitor of JAK3, CP-690,550, that significantly prolonged survival in a murine model of heart transplantation and in cynomolgus monkeys receiving kidney transplants. CP-690,550 treatment was not associated with hypertension, hyperlipidemia, or lymphoproliferative disease. On the basis of these preclinical results, we believe JAK3 blockade by CP-690,550 has potential for therapeutically desirable immunosuppression in human organ transplantation and in other clinical settings.     

Experimental acidification of Little Rock Lake,Wisconsin

The controlled acidification of a two-basin lake is described. The lake was divided by a vinyl curtain in 1984; acidification of one basin began in 1985. Target pH values of 5.5, 5.0 and 4.5 are planned for 2-yr increments. Biotic and chemical responses and internal alkalinity generation are being studied. Baseline studies, initial results at pH 5.5, and predictions of lake responses to acidification are described.