Highly economical and direct amination of sp carbon using low-cost nickel pincer catalyst.

Developing more efficient routes to achieve C-N bond coupling is of great importance to industries ranging from products in pharmaceuticals and fertilizers to biomedical technologies and next-generation electroactive materials. Over the past decade, improvements in catalyst design have moved synthesis away from expensive metals to newer inexpensive C-N cross-coupling approaches direct amine alkylation. For the first time, we report the use of an amide-based nickel pincer catalyst (1) for direct alkylation of amines activation of sp C-H bonds.

Microcirculation in pancreatic function.

The pancreas is involved in two major bodily functions: production of hormones involved in the control of carbohydrate metabolism and the production of enzymes essential to digestion. Pancreatic function is mediated by both neurological and humoral control. The major pathway for humoral control is through the circulatory system, the level of action being in the microcirculation.

Pentagastrin enhances gastric mucosal defenses in vivo: luminal acid-dependent and independent effects.

Stimulation of acid secretion is associated with enhanced resistance of the gastric mucosa to damage by luminal acid. We studied the mechanism by which gastric mucosal defenses are modulated in a system in which mucus gel thickness, intracellular pH (pHi), gastric mucosal blood flow, and acid secretion can be measured simultaneously in vivo, using a recently developed microfluorometric technique. Intravenous infusion of pentagastrin in a dose associated with maximal acid secretion increased mucus gel thickness, pHi, and mucosal blood flow during superfusion with a neutral solution.

Intravital observatories. Dream or necessity.

Among the major challenges confronting biomedical studies today two stands out above all others: 1. The need for a better interrelation of the remarkable findings of molecular and cell biology to living systems through careful intravital observation; and 2. The need for a more rapid and skillful application of the findings and methods of intravital observation to clinical applications.

Role of arachidonic acid metabolites in ethanol vasoaction in rat gastric submucosa.

By use of an in vivo microscopy technique in the anesthetized rat, the effect of 0.5-8.0% ethanol on gastric submucosal blood vessel diameter was studied.

Microcirculatory stasis precedes tissue necrosis in ethanol-induced gastric mucosal injury in the rat.

The relation of blood flow stasis to the development of unequivocal histologic necrosis (loss of parietal cells from the column of contiguous cells) in ethanol-induced gastric mucosal injury was studied in anesthetized rats. The most rapid vascular change that occurred when the gastric mucosa was exposed to 100% ethanol was a severe segmental constriction of the large submucosal venules. At 22 sec, the average venular diameter was 52.

Permeability characteristics of microvascular walls.

Blood to lymph transport of macromolecules has been modeled by assuming a rather numerous population of small pores and a considerably smaller population of large pores across the microvascular walls. Such "black box" studies, however, are inherently incapable of identifying the precise pathways of movement. Electron microscopy has shown a variety of structures which might be identified as the "pores".

Use of telescopic imaging in intravital microscopy: a simple solution for conventional microscopes.

Conventional microscopes can be adapted for telescopic imaging by using a projection eyepiece which focuses the image formed by a standard microscope objective at such a large distance that light emanating from points on the object leaves the eyepiece as parallel bundles. A telescopic transfer lens forms the final image in its focal plane independent of the distance between the eyepiece and the transfer lens. In the system reported in this paper, the distance between the eyepiece and transfer lens can be varied from 0 to 280 mm without appreciable vignetting or image degradation for imaging on 35 mm film or smaller formats.