New directions in the relation between public and private debt     

Friedman BM 《Science (New York, N.Y.)》1987,236(4800):397-403

Until the 1980s the outstanding indebtedness of government and private-sector borrowers in the United States exhibited sufficient negative covariation that total outstanding debt remained steady relative to nonfinancial economic activity. Three hypotheses-one based on lenders' behavior, one on borrowers' behavior, and one on credit market institutional arrangements-provide potential explanations for this phenomenon. Since 1980 the U.S. debt markets have departed from these previously prevailing patterns, however, as both government and private borrowing have risen sharply.  相似文献   

X-ray line and continuum spectra of solar flares from 0.5 to 8.5 angstroms     

Meekins JF  Kreplin RW  Chubb TA  Friedman H 《Science (New York, N.Y.)》1968,162(3856):891-895

Two crystal spectrometers aboard the orbiting solar observatory OSO-4 cover the wavelength ranges 0.5 to 3.9 angstroms and 1.0 to 8.5 angstroms. Within this range, there appear emission lines from hydrogen-like and helium-like states of calcium, sulfur, silicon, magnesium, and aluminum. The Mg XII Lyman-alpha is present strongly in all x-ray flares. The most intense flares (such as class 3) produce strong Si XIV Lyman-alpha and often S XVI Lyman-alpha. Emission, in the form of Ka lines of highly ionized states of calcium, iron, aluminum, and silicon is usually present. The continuum from 1 to 10 angstroms always dominates the line emission by more than an order of magnitude. Electron temperatures derived from the slope of the continuum spectrum are in the range of 10(7) to 10(8) degrees K, considerably higher than theoretical ionization equilibrium temperatures.  相似文献   

ER tubules mark sites of mitochondrial division   总被引：1，自引：0，他引：1  

Friedman JR  Lackner LL  West M  DiBenedetto JR  Nunnari J  Voeltz GK 《Science (New York, N.Y.)》2011,334(6054):358-362

Mitochondrial structure and distribution are regulated by division and fusion events. Mitochondrial division is regulated by Dnm1/Drp1, a dynamin-related protein that forms helices around mitochondria to mediate fission. Little is known about what determines sites of mitochondrial fission within the mitochondrial network. The endoplasmic reticulum (ER) and mitochondria exhibit tightly coupled dynamics and have extensive contacts. We tested whether ER plays a role in mitochondrial division. We found that mitochondrial division occurred at positions where ER tubules contacted mitochondria and mediated constriction before Drp1 recruitment. Thus, ER tubules may play an active role in defining the position of mitochondrial division sites.  相似文献   

PROFESSOR PAWLOW'S RESEARCHES ON THE PHYSIOLOGY OF SECRETION     

Mendel LB 《Science (New York, N.Y.)》1901,14(356):647-649

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Purine resistant mutants of Drosophila are adenine phosphoribosyltransferase deficient     

Johnson DH  Friedman TB 《Science (New York, N.Y.)》1981,212(4498):1035-1036

A deficiency for adenine phosphoribosyltransferase activity is the primary biochemical defect in mutants of Drosophila selected for resistance to purine-induced lethality.  相似文献   

Pseudomonas fluorescens in relation to certain diseases of potato tubers in Maine     

Donald Folsom  B. A. Friedman 《American Journal of Potato Research》1959,36(3):90-97

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Errata — March 1959 issue     

Donald Folsom  B. A. Friedman 《American Journal of Potato Research》1959,36(4):146-146

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Analysis of phenolic compounds by high-performance liquid chromatography and liquid chromatography/mass spectrometry in potato plant flowers, leaves, stems, and tubers and in home-processed potatoes   总被引：2，自引：0，他引：2  

Im HW  Suh BS  Lee SU  Kozukue N  Ohnisi-Kameyama M  Levin CE  Friedman M 《Journal of agricultural and food chemistry》2008,56(9):3341-3349

Potato plants synthesize phenolic compounds as protection against bruising and injury from bacteria, fungi, viruses, and insects. Because antioxidative phenolic compounds are also reported to participate in enzymatic browning reactions and to exhibit health-promoting effects in humans, a need exists for accurate methods to measure their content in fresh and processed potatoes. To contribute to our knowledge about the levels of phenolic compounds in potatoes, we validated and used high-performance liquid chromatography and liquid chromatography/mass spectrometry to measure levels of chlorogenic acid, a chlorogenic isomer, and caffeic acid in flowers, leaves, stems, and tubers of the potato plant and in home-processed potatoes. The total phenolic acid content of flowers (626 mg/100 g fresh wt) was 21 and 59 times greater than that of leaves and stems, respectively. For all samples, chlorogenic acid and its isomer contributed 96-98% to the total. Total phenolic acid levels (in g/100 g fresh wt) of peels of five potato varieties grown in Korea ranged from 6.5 to 42.1 and of the flesh (pulp) from 0.5 to 16.5, with peel/pulp ratios ranging from 2.6 to 21.1. The total phenolic acid content for 25 American potatoes ranged from 1.0 to 172. The highest amounts were present in red and purple potatoes. Home processing of pulp with various forms of heat induced reductions in the phenolic content. The described methodology should facilitate future studies on the role of potato phenolic compounds in the plant and the diet.  相似文献   

Potato glycoalkaloids and metabolites: roles in the plant and in the diet     

Friedman M 《Journal of agricultural and food chemistry》2006,54(23):8655-8681

Potatoes, members of the Solanaceae plant family, serve as major, inexpensive low-fat food sources providing energy (starch), high-quality protein, fiber, and vitamins. Potatoes also produce biologically active secondary metabolites, which may have both adverse and beneficial effects in the diet. These include glycoalkaloids, calystegine alkaloids, protease inhibitors, lectins, phenolic compounds, and chlorophyll. Because glycoalkaloids are reported to be involved in host-plant resistance and to have a variety of adverse as well as beneficial effects in cells, animals, and humans, a need exists to develop a clearer understanding of their roles both in the plant and in the diet. To contribute to this effort, this integrated review presents data on the (a) history of glycoalkaloids; (b) glycoalkaloid content in different parts of the potato plant, in processed potato products, and in wild, transgenic, and organic potatoes; (c) biosynthesis, inheritance, plant molecular biology, and glycoalkaloid-plant phytopathogen relationships; (d) dietary significance with special focus on the chemistry, analysis, and nutritional quality of low-glycoalkaloid potato protein; (e) pharmacology and toxicology of the potato glycoalkaloids comprising alpha-chaconine and alpha-solanine and their hydrolysis products (metabolites); (f) anticarcinogenic and other beneficial effects; and (g) possible dietary consequences of concurrent consumption of glycoalkaloids and other biologically active compounds present in fresh and processed potatoes. An enhanced understanding of the multiple and overlapping aspects of glycoalkaloids in the plant and in the diet will benefit producers and consumers of potatoes.  相似文献   

The role of <Emphasis Type="Italic">Euwallacea</Emphasis> nr. <Emphasis Type="Italic">fornicatus</Emphasis> (Coleoptera: Scolytinae) in the wilt syndrome of avocado trees in Israel     

Zvi Mendel  Alex Protasov  Yonatan Maoz  Marcel Maymon  Golan Miller  Meirav Elazar  Stanley Freeman 《Phytoparasitica》2017,45(3):341-359

The polyphagous shot hole borer (PSHB), Euwallacea nr. fornicatus (Coleoptera; Scolytinae) has become a serious threat to the avocado industry and several shade tree species in Israel. Branch wilting and tree mortality is the outcome of PSHB galleries. Understanding the relationship between avocado trees and the PSHB is required for considering management strategies. In Israel, 52 tree species from 26 botanical families were attacked by the PSHB, but only 12 species were suitable for beetle reproduction. All examined avocado cultivars were attacked, but ‘Hass’ most severely. Large and medium diameter avocado branches were more resistant to PSHB, compared to thin branches. Effectively, gallery density increased as branch diameter decreased. Concomitantly, in large and medium diameter branches, extensive sugar exudation occurred and beetle attack rarely progressed to the formation of natal galleries, whereas minimal sugar exudation was observed in thin branches. This was more evident in those that were weakened by repeated attacks followed by successful beetle colonization. PSHB prefers and successfully colonized branches that had been previously attacked by its conspecifics, and reproduction was much higher in these branches, as opposed to initial attacks. Lesion frequencies increased from late spring (April) until late summer (September). Avocado branches at the early stages of beetle colonization may be identified by sugar exudation at the base of the thin branches. The main approach for reducing damage caused by the PSHB is sanitation, achieved by the removal of colonized branches and intact infested pruned slash.  相似文献