Silver

Paper Dreams: Universe Books New York City 10016 $6.95 paper $11.95 cloth. Reviewed by Lorraine Bodger

String Art Encyclopedia Sterling Publishing Co., Inc. New York City 10016 $8.95. Reviewed by Lorraine Bodger

Card Weaving: New York City 10001 $12.95. Reviewed by Ruth J. Katz Van Nostrand Reinhold Co.

Images in Sand: University Press of Kentucky Lexington, KY 40506 $12.95. Reviewed by Janis Sternbergs

The Ups and Downs of Needlepoint: A.S. Barnes and Co. Cranbury, NJ 08512 $17.50. Reviewed by Fannie Hillsmith

Anyone Can Paint-I Promise: David McKay Co., Inc. New York City 10017 $10.95. Reviewed by Robert H. Garden

Designing in Batik &; Tie Dye: Prentice-Hall, Inc. Englewood Cliffs, NJ 07632 $6.95. Reviewed by Nancy Belfer     

Microwaves Applied to Silver Impregnations with Ammoniacal Silver Carbonate

Techniques for impregnation with ammoniacal silver carbonate provide valuable information on all types of tissue; however, the time investment required to impregnate a few sections has limited their application. We have shortened the impregnation times by using microwaves in techniques for reticular fibers, astrocytes, nerve fibers and chromaffin cells. The results were satisfactory with markedly reduced impregnation time and elimination of nonspecific silver deposits.     

Silver nanoparticles: partial oxidation and antibacterial activities

The physical and chemical properties of silver nanoparticles that are responsible for their antimicrobial activities have been studied with spherical silver nanoparticles (average diameter approximately 9 nm) synthesized by the borohydride reduction of Ag+ ions, in relation to their sensitivity to oxidation, activities towards silver-resistant bacteria, size-dependent activities, and dispersal in electrolytic solutions. Partially (surface) oxidized silver nanoparticles have antibacterial activities, but zero-valent nanoparticles do not. The levels of chemisorbed Ag+ that form on the particle's surface, as revealed by changes in the surface plasmon resonance absorption during oxidation and reduction, correlate well with the observed antibacterial activities. Silver nanoparticles, like Ag+ in the form of AgNO3 solution, are tolerated by the bacteria strains resistant to Ag+. The antibacterial activities of silver nanoparticles are related to their size, with the smaller particles having higher activities on the basis of equivalent silver mass content. The silver nanoparticles aggregate in media with a high electrolyte content, resulting in a loss of antibacterial activities. However, complexation with albumin can stabilize the silver nanoparticles against aggregation, leading to a retention of the antibacterial activities. Taken together, the results show that the antibacterial activities of silver nanoparticles are dependent on chemisorbed Ag+, which is readily formed owing to extreme sensitivity to oxygen. The antibacterial activities of silver nanoparticles are dependent on optimally displayed oxidized surfaces, which are present in well-dispersed suspensions.     

Silver Plated Ribosomes

WE recently reported that dissociation of free 70S ribosomes from E. coli to 30S and 50S subunits could occur during sedimentation in buffer containing K⁺ as the predominant monovalent cation¹. Spermidine at a physiological concentration (1 mM) specifically prevented the dissociation and we suggested that the dissociation that occurred in its absence was due to loss of the polyamine from the 70S ribosome. We have subsequently found that this hypothesis is wrong and that the dissociation that took place in the original experiments was due not primarily to loss of spermidine, but to a reaction with silver present in very small amounts in the AR KCl used in the buffer.     

Silver nanoparticles: the powerful nanoweapon against multidrug-resistant bacteria

In the present scenario, pharmaceutical and biomedical sectors are facing the challenges of continuous increase in the multidrug-resistant (MDR) human pathogenic microbes. Re-emergence of MDR microbes is facilitated by drug and/or antibiotic resistance, which is acquired way of microbes for their survival and multiplication in uncomfortable environments. MDR bacterial infections lead to significant increase in mortality, morbidity and cost of prolonged treatments. Therefore, development, modification or searching the antimicrobial compounds having bactericidal potential against MDR bacteria is a priority area of research. Silver in the form of various compounds and bhasmas have been used in Ayurveda to treat several bacterial infections since time immemorial. As several pathogenic bacteria are developing antibiotic resistance, silver nanoparticles are the new hope to treat them. This review discusses the bactericidal potential of silver nanoparticles against the MDR bacteria. This multiactional nanoweapon can be used for the treatment and prevention of drug-resistant microbes.     

Fluorescence Enhancement Caused by Plasmonics Coupling Between Silver Nano-Cubes and Silver Film

In this article, we experimentally investigated the plasmonics interaction in the system composed of Ag nano-cubes on Ag film with controlled distance. The distance is controlled by Rhodamine B (RhB)-doped polymethylmethacrylate (PMMA) film as the spacer, whose fluorescence intensity was then enhanced by the plasmonics interaction. Experimental results show that the fluorescence enhancement is sensitive to the thickness of the spacer. The largest enhancement factor obtained is 521 with the RhB-doped PMMA film of 10 nm thickness. For comparison, we also presented the fluorescence enhancement caused by only the localized surface plasmons from Ag nano-cubes on glass substrate coated with RhB-doped PMMA film, which gives out lower enhancement factors at the same thick spacer. Our experimental results are consistent with previous theoretical investigation and shows promising applications in fluorescence based bio-sensing or bio-imaging.     

Silver nitrate prophylaxis.

In many countries the statutory use of silver nitrate prophylaxis as soon as possible after birth has recently been reviewed from both a human rights and a medical standpoint. It has been argued that silver nitrate does not prevent all cases of gonococcal ophthalmia neonatorum (GON) and that it causes chemical conjunctivitis, pain and visual impairment, which may interfere with parent-infant bonding. Furthermore, the low incidence of GON, better methods of prenatal diagnosis, and the availability of suitable alternative prophylactic medication and of effective methods of treatment of GON have prompted recommendations that alternative prophylaxis be legally allowed or that mandatory prophylaxis be eliminated altogether. This paper reviews the situation and provides updated recommendations.     

广西本地鲢和长丰鲢群体遗传多样性分析

本研究采用32个微卫星标记分析广西本地鲢和长丰鲢两个群体的遗传差异,计算并统计其微卫星遗传参数。结果显示:32个微卫星标记广西本地鲢鱼和长丰鲢群体共检测到等位基因119个,其中两群体所共有为88个;平均观测等位基因数为2.937 5和3.406 2;平均有效等位基因数为1.787 3和2.074 7;多态信息含量(PIC)在0～0.727 1和0～0.748 4之间,平均值为0.293 6和0.360 0,表明两个群体的遗传多样性均不高。两群体平均观测杂合度为0.373 9和0.559 7,平均期望杂合度为0.327 1和0.413 3,均表现为本地鲢群体低于长丰鲢群体,说明两个群体的均不高,并且广西本地鲢群体的遗传多样性低于长丰鲢群体;两个鲢鱼群体间的遗传距离和遗传相似系数分别为0.297 7和0.742 5,表明两个鲢鱼群体间的遗传差异不大。两个群体的遗传分化系数(Fst)在不同微卫星位点间差异明显,平均0.171 7。本研究为广西地方鱼类种质资源保护和利用提供了理论依据。