Extracellular pH regulation in microdomains of colonic crypts: effects of short-chain fatty acids.

It has been suggested that transepithelial gradients of short-chain fatty acids (SCFAs; the major anions in the colonic lumen) generate pH gradients across the colonic epithelium. Quantitative confocal microscopy was used to study extracellular pH in mouse distal colon with intact epithelial architecture, by superfusing tissue with carboxy SNARF-1 (a pH-sensitive fluorescent dye). Results demonstrate extracellular pH regulation in two separate microdomains surrounding colonic crypts: the crypt lumen and the subepithelial tissue adjacent to crypt colonocytes. Apical superfusion with (i) a poorly metabolized SCFA (isobutyrate), (ii) an avidly metabolized SCFA (n-butyrate), or (iii) a physiologic mixture of acetate/propionate/n-butyrate produced similar results: alkalinization of the crypt lumen and acidification of subepithelial tissue. Effects were (i) dependent on the presence and orientation of a transepithelial SCFA gradient, (ii) not observed with gluconate substitution, and (iii) required activation of sustained vectorial acid/base transport by SCFAs. Results suggest that the crypt lumen functions as a pH microdomain due to slow mixing with bulk superfusates and that crypts contribute significant buffering capacity to the lumen. In conclusion, physiologic SCFA gradients cause polarized extracellular pH regulation because epithelial architecture and vectorial transport synergize to establish regulated microenvironments.

Avoiding Extinction: An Evaluation of Short-Term Recovery Recommendations for the Endangered Rio Grande Silvery Minnow

The endangered Rio Grande silvery minnow (Hybognathus amarus; RGSM) is nearing extinction and requires immediate recovery actions. In a draft report to the Middle Rio Grande Program, a Program Advisory Panel (PAP) recommended 34 short-term recovery measures to be implemented within the next five years, and 21 long-term recovery actions. However, these recommendations need further analysis to determine if and how the actions could be implemented. This project evaluated short-term recommendations provided by the PAP to identify the most effective and rank the relative importance of the actions. These recommendations were divided into 7 recovery categories: population augmentation (5 recommendations); hydrologic regimen (4 recommendations); physical habitat (3 recommendations); biological component of habitat (2 recommendations); population monitoring (6 recommendations); monitoring, analysis, and modeling (12 recommendations); and information and planning (2 recommendations). Each recommendation was evaluated for its potential to produce anticipated recovery progress for the RGSM based on assessments of the degree of feasibility, cost effectiveness, and associated potential consequences if fully implemented. In addition, other alternatives in a range of options were also considered where applicable. In each case, recommendations were evaluated from on-site visits, interviews with researchers and resource managers, and literature review. Based on the research findings, three major groupings of the recovery categories were identified: natural aspects of recovery, program aspects of recovery, and emergency measures. At least one recovery category within each major grouping was considered important by the respondents, which indicates that each grouping is of high importance in relation to the situation at hand. However, actions within each grouping have varying priorities given constraints on available resources, time, and budget. An integrated approach that accounts for the complexity of the river system and the species itself was considered the best approach to avoid extinction while ensuring long-term sustainability. Results of these analyses were provided directly to the PAP for their review, and it is anticipated that project results could advance implementation of the most appropriate immediate recovery actions needed to prevent extinction of the RGSM.

Selections from the world's greatest short stories; illustrative of the history of short story writing;

Patient Griselda, from the "Decameron" of Boccaccio. Rewritten in English by the editor.--Aladdin, or The wonderful lamp, from "The Arabian nights".--Rip Van Winkle, by Washington Irving.--A passion in the desert, by Honoré de Balzac. Rewritten in English by the editor.--A child's dream of a star, by Charles Dickens.--A Christmas carol, by Charles Dickens.--A princess's tragedy, from "Barry Lyndon", by W.M. Thackeray.--The gold-bug, by Edgar Allan Poe.--The great stone face, by Nathaniel Hawthorne.--The necklace, and The string, by Guy de Maupassant. Rewritten in English by the editor.--The man who would be king, by Ruyard Kipling.--How Gavin Birse put it to Mag Lownie, from "A window in Thrums", by J.M. Barrie.--On the stairs, from "Tales of mean streets", by Arthur Morrison.

Analysis of short-term variations in beach morphology (and concurrent dynamic processes) for summer and winter periods, 1971-72, Plum Island, Massachusetts /

"March 1977."

Neutron activation analysis by means of short-lived isotopes /

"Department of Chemistry, University of Michigan"

The children's book; a collection of short stories and poems. A mormon book for Mormon Children.

Mode of access: Internet.

A selection from the world's greatest short stories, illustrative of the history of short story writing.

Mode of access: Internet.

Temperature in streams of New Mexico for the period October 1964 to September 1969 /

Nov. 1978.

Welded pipe fabrication; a course of instruction explaining all common cuts and layouts made on pipe, with explanations of short methods, the mathematics needed, and the tools used in developing patterns for, calculating, and fabricating any welded piping system.

Mode of access: Internet.

The application of short-duration techniques to the experimental study of base heating

"Presented at the 2nd Symposium of Rocket Testing in Simulated Space and High-Altitude Environments at Arnold Engineering development Center, Tullahoma, Tennessee."

The story-life of Napoleon; hundreds of short stories from the greatest variety of sources reconciled and fitted together in a complete and continuous biography,

Mode of access: Internet.

First progress report on hydraulics of short pipes : hydraulic characteristics of commonly used pipe entrances /

Mode of access: Internet.

Seek and find; a double series of short studies of the Benedicite.

Publisher's catalog at end.

An intensive survey of Shawnee National Forest region streams of southern Illinois, 1986-1987 /

"IEPA/WPC/90-171."--Cover.