Plasmonic Resonances and Electromagnetic Forces Between Coupled Silver Nanowires

We compute the electromagnetic response and corresponding forces between two silver nanowires. The wires are illuminated by a plane wave which has the electric field vector perpendicular to the axis of the wires, insuring that plasmonic resonances can be excited. We consider a nontrivial square cross section geometry that has dimensions on the order of $0.1 \lambda$, where $\lambda$ is the wavelength of the incident electromagnetic field. We find that due to the plasmonic resonance, there occurs great enhancement of the direct and mutual electromagnetic forces that are exerted on the nanowires. The Lippman-Schwinger volume integral equation is implemented to obtain solutions to Maxwell's equations for various $\lambda$ and separation distances between wires. The forces are computed using Maxwell's stress tensor and numerical results are shown for both on and off resonant conditions

Proceedings of a Conference on Agricultural Education in Our Public Schools

Vocational Agriculture has played an important role in helping young men become established in farming. Much of our success in more than meeting the food and fiber needs of our rapidly growing population today can b~ attributed to Vocational Agriculture. But, questions are being raised about the need for cominuation of such an extensive program of preparation for farming in view of the reduced number of farming opportunities each year. Furthermore, questions are being raised about the adeqwacy of preparation for farming by a program that is terminal at the high school level, and about the adequacy of preparation for college if a student devotes much of his high school time to Vocational Agriculture.https://lib.dr.iastate.edu/card_reports/1000/thumbnail.jp

Transfer of immunoglobulins through the mammary endothelium and epithelium and in the local lymph node of cows during the initial response after intramammary challenge with E. coli endotoxin

<p>Abstract</p> <p>Background</p> <p>The first hours after antigen stimulation, interactions occur influencing the outcome of the immunological reaction. Immunoglobulins originate in blood and/or are locally synthesized. The transfer of Ig isotypes (Igs) in the udder has been studied previously but without the possibility to distinguish between the endothelium and the epithelium. The purpose of this study was to map the Ig transfer through each barrier, separately, and Ig transfer in the local lymph nodes of the bovine udder during the initial innate immune response.</p> <p>Methods</p> <p>The content of IgG1, IgG2, IgM, IgA and albumin (BSA) was examined in peripheral/afferent mammary lymph and lymph leaving the supramammary lymph nodes, and in blood and milk before (0 h) and during 4 hours after intramammary challenge with <it>Esherichia coli </it>endotoxin in 5 cows.</p> <p>Results</p> <p>Igs increased most rapidly in afferent lymph resulting in higher concentrations than in efferent lymph at postinfusion hour (PIH) 2, contrary to before challenge. Ig concentrations in milk were lower than in lymph; except for IgA at 0 h; and they increased more slowly. <it>Afferent lymph:serum </it>and <it>efferent lymph:serum </it>concentration ratios (CR) of Igs were similar to those of BSA but slightly lower. <it>Milk:afferent lymph </it>(M:A) CRs of each Ig, except for IgG2, showed strikingly different pattern than those of BSA. The M:A CR of IgG1, IgM and IgA were higher than that of BSA before challenge and the CR of IgA and IgG1 remained higher also thereafter. At PIH 2 there was a drop in Ig CRs, except for IgG2, in contrast to the BSA CR which gradually increased. The M:A CR of IgM and Ig A <it>decreased </it>from 0 h to PIH 4, in spite of increasing permeability.</p> <p>Conclusion</p> <p>The transfer of Igs through the <it>endothelium </it>appeared to be merely a result of diffusion although their large molecular size may hamper the diffusion. The transfer through the <it>epithelium </it>and the Ig concentrations in milk seemed more influenced by selective mechanisms and local sources, respectively. Our observations indicate a selective mechanism in the transfer of IgG1 through the epithelium also in lactating glands, not previously shown; a local synthesis of IgA and possibly of IgM, released primarily into milk, not into tissue fluid; that IgG2 transfer through both barriers is a result of passive diffusion only and that the content of efferent lymph is strongly influenced by IgG1, IgM and IgA in the mammary tissue, brought to the lymph node by afferent lymph.</p

Aqueous-Phase Synthesis of Silver Nanodiscs and Nanorods in Methyl Cellulose Matrix: Photophysical Study and Simulation of UV–Vis Extinction Spectra Using DDA Method

We present a very simple and effective way for the synthesis of tunable coloured silver sols having different morphologies. The procedure is based on the seed-mediated growth approach where methyl cellulose (MC) has been used as soft-template in the growth solution. Nanostructures of varying morphologies as well as colour of the silver sols are controlled by altering the concentration of citrate in the growth solution. Similar to the polymers in the solution, citrate ions also dynamically adsorbed on the growing silver nanoparticles and promote one (1-D) and two-dimensional (2-D) growth of nanoparticles. Silver nanostructures are characterized using UV–vis and HR-TEM spectroscopic study. Simulation of the UV–vis extinction spectra of our synthesized silver nanostructures has been carried out using discrete dipole approximation (DDA) method

TRANSPORT JC(B,T) AND FLUX PINNING BEHAVIOR IN MELT-TEXTURED BI-SR-CA-CU-O HIGH-T(C) SUPERCONDUCTORS

The magnetic field dependence of the transport critical current densities (Jc) in the temperature range 20-70 K has been measured on melt-textured Bi-Sr-Ca-Cu-O samples. Jc decreased approximately exponentially with magnetic field. The characteristic magnetic field B*, determined as the magnetic field at which extrapolated Jc(B) decreased to a certain level, increased slowly with decreasing temperature in the temperature range 70-30 K but a rapid increase below 30 K was observed. Fp(B,T) and fp(b,T) dependences, with fp=F p/Fp max and b=B/B*, are presented. A scaling behaviour of fp(b,T) similar to that of conventional superconductors was found

MAGNETIC-FIELD DEPENDENCE OF THE TRANSPORT CRITICAL CURRENT-DENSITY IN MELT-TEXTURED BI-SR-CA-CU-O HIGH-TC SUPERCONDUCTORS

The transport critical current densities (Jc) in magnetic fields up to 14 T at 4.2 K have been measured on melt-textured Bi-Sr-Ca-Cu-O samples on MgO substrates. The samples were multiphase with partial alignment of the grains. Jc values of 1.58*104 A/cm2, 1.13*104 A/cm2 and 8.2*103 A/cm2were obtained in magnetic fields B=0 T, 1 T and 14 T, respectively. The magnetic field dependence of Jc was relatively flat in fields higher than 1 T. The flux pinning force density increased monotonically in the whole range of fields. The shape of the current-voltage characteristics has been examined and shown to follow approximately a power-law behaviour E approximately Jn in the range of E-values of 10 -4-10-1 V/m with n approximately=30. Preliminary results of Jc(B,T) measurements at higher temperatures are presented

The human beta 2-microglobulin gene. Primary structure and definition of the transcriptional unit

The human genomic clone pb2m13 contains a functional beta 2-microglobulin (B2m) gene, which upon transfection is readily expressed in murine fibroblasts. Here we report the nucleotide sequence of the human beta 2m gene and of a nearly full length cDNA clone. A comparison with the murine beta 2m gene reveals that exon/intron boundaries are absolutely conserved. In the protein-coding regions the similarity is 70%. As far as intron sequences of the murine beta 2m gene are available, no significant similarity between human and murine genes is observed. The transcriptional start site of the human beta 2m gene was determined by S1 mapping, and comparison with the nearly full length cDNA clone now defines the transcriptional unit of the beta 2m gene. In the 5' region of the gene strong clustering of the usually underrepresented CpG dinucleotide is found resembling a similar overrepresentation in the 5' regions of the major histocompatibility complex class I gene