Auditory membrane vibrations: measurements at sub-angstrom levels by optical heterodyne spectroscopy

We describe an optical technique for measurement of mechanical vibrations in the auditory organs of living animals. The technique uses light scattered from the vibrating structure and offers several new advantages. Better than 1 angstrom sensitivity, 10 micrometers spatial resolution, and > 70 decibels dynamic range are achieved. Illustrative measurements of the mechanical response of the tympanic membrane of crickets (Gryllidae) are reported.     

Carbon structures with three-dimensional periodicity at optical wavelengths

Porous carbons that are three-dimensionally periodic on the scale of optical wavelengths were made by a synthesis route resembling the geological formation of natural opal. Porous silica opal crystals were sintered to form an intersphere interface through which the silica was removed after infiltration with carbon or a carbon precursor. The resulting porous carbons had different structures depending on synthesis conditions. Both diamond and glassy carbon inverse opals resulted from volume filling. Graphite inverse opals, comprising 40-angstrom-thick layers of graphite sheets tiled on spherical surfaces, were produced by surface templating. The carbon inverse opals provide examples of both dielectric and metallic optical photonic crystals. They strongly diffract light and may provide a route toward photonic band-gap materials.     

Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.     

Cytochrome a3: destruction by light

Spectroscopic measurements on cultures of Prototheca zopfii irradiated with blue light revealed that inhibition of respiration was accompanied by destruction of cytochrome a(3). One of the three b-type cytochromes and one of the two c-type cytochromes of this organism were also affected. Cytochrome oxidase of yeast (not resolved into the a and a(3) components) and cytochrome a(3) of beef-heart mitochondria were also destroyed by blue light.     

Scanning interferometric apertureless microscopy: optical imaging at 10 angstrom resolution

Interferometric near-field optical microscopy achieving a resolution of 10 angstroms is demonstrated. The scattered electric field variation caused by a vibrating probe tip in close proximity to a sample surface is measured by encoding it as a modulation in the optical phase of one arm of an interferometer. Unlike in regular near-field optical microscopes, where the contrast results from a weak source (or aperture) dipole interacting with the polarizability of the sample, the present form of imaging relies on a fundamentally different contrast mechanism: sensing the dipole-dipole coupling of two externally driven dipoles (the tip and sample dipoles) as their spacing is modulated.     

Conformations at local energy minimums for gramicidin S: optical calculations

Energy minimization techniques applied to an arbitrary peptide primary sequence result in a still large number of hypothetical structures of similar energy. Optical activity calculations can, in principle, be used to screen the low-energy conformations. Those conformations which yield a spectrum different from the observed spectrum by a factor greater than the current reliability of the calculation can be excluded. The method is applied to gramicidin S.     

Cherenkov radiation at speeds below the light threshold: phonon-assisted phase matching

Charged particles traveling through matter at speeds larger than the phase velocity of light in the medium emit Cherenkov radiation. Calculations reveal that a given angle of the radiation conical wavefront is associated with two velocities, one above and one below a certain speed threshold. Emission at subluminal but not superluminal speeds is predicted and verified experimentally for relativistic dipoles generated with an optical method based on subpicosecond pulses moving in a nonlinear medium. The dipolar Cherenkov field, in the range of infrared-active phonons, is identical to that of phonon polaritons produced by impulsive laser excitation.     

Antibodies to deoxyribonucleic acid irradiated with ultraviolet light: detection by precipitins and immunofluorescence

Two rabbits were immunized with a complex consisting of ultravioietirradiated DNA and methylated bovine serum albumin. Serum antibodies reacted only with irradiated DNA, and the serological reaction was shown by immuneprecipitation and immunofluorescence.     

Pars intermedia: unitary electrical activity regulated by light

In the pars intermedia of frogs in the dark two types of spontaneously firing neuronal units have been found; one can be inhibited by and the other is indifferent to increases in illumination. The receptor for the light-inhibited units appears to be the pineal organ. Transection experiments indicate that the axons to the two kinds of units in the pars intermedia are separately grouped in the floor.     

Seeing with a new light: synchrotron radiation

The special properties of synchrotron light are leading to a rapid increase in its utilization for both research and technology. At wavelength in the ultraviolet region of the broad spectrum in these beams a number of atomic, molecular, and solid-state spectroscopies are being pursued; soft x-rays are being used for spectroscopy, lithography, microscopy, and topography; at still shorter wavelengths, advantage is taken of scattering properties to probe the structure of matter. Characteristics of synchrotron radiation and of the sources which produce it are described, and some typical investigations and applications are presented to suggest the versatility of these sources.     

北太平洋海域白天利用水下灯钓捕大型柔鱼的试验报告

光诱鱿钓捕捞技术就是利用鱿鱼趋光、集群的特性 ,采用钩钓作业的一种渔法。利用水下灯进行钓捕鱿鱼是一种新的捕捞技术。该技术在 80年代中期首先在日本、韩国等国的鱿钓船中得到应用。分布在北太平洋中部海域的大型柔鱼 ( 1～ 2ｋｇ) ,栖息水层白天一般在 30 0～ 40 0ｍ ,使用水下灯进行深水层的诱集柔鱼 ,使白天作业成为可能 ,从而大大延长了作业时间。由于柔鱼具有昼夜垂直移动现象 ,夜间栖息水层为 30～ 40ｃｍ ,因而一般不采用水下灯。我国鱿钓船从 1 997年开始 ,初步得到应用 ,特别是在 1 998年鱿钓渔场探捕调查和生产过程中 ,取得了…     

Azotobacter cysts: reactivation by white light after inactivation by ultraviolet radiation

Cysts of Azotobacter vinelandii 12837 inactivated by ultraviolet radiation can be reactivated by white light. This photoreactivation mechanism is not seen in the vegetative cells of the same organism.     

北太平洋海域白天利用水下灯钓捕大型柔鱼的试验报告

光诱鱿钓捕捞技术就是利用鱿鱼趋光、集群的特性 ,采用钩钓作业的一种渔法。利用水下灯进行钓捕鱿鱼是一种新的捕捞技术。该技术在 80年代中期首先在日本、韩国等国的鱿钓船中得到应用。分布在北太平洋中部海域的大型柔鱼 ( 1～ 2ｋｇ) ,栖息水层白天一般在 30 0～ 40 0ｍ ,使用水下灯进行深水层的诱集柔鱼 ,使白天作业成为可能 ,从而大大延长了作业时间。由于柔鱼具有昼夜垂直移动现象 ,夜间栖息水层为 30～ 40ｃｍ ,因而一般不采用水下灯。我国鱿钓船从 1 997年开始 ,初步得到应用 ,特别是在 1 998年鱿钓渔场探捕调查和生产过程中 ,取得了…     

Sr lattice clock at 1 x 10(-16) fractional uncertainty by remote optical evaluation with a Ca clock

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 x 10(-16) fractional level, surpassing the current best evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation-induced frequency shifts.     

Physical support with and without optical support: reaction to apprarent depth by chicks and rats

The locomotor reactions to apparent depth made by chicks and rats were measured in situations offering physical support with and without optical information for support. Chicks avoided an optical void though it provided physical support. Rats responded indifferently to the presence or absence of optical information for support as long as physical support was available.     

光诱导c-fos基因在不同日龄母鸡中脑和间脑的表达

为了进一步探讨光照对母鸡生产性能的影响机制,用c-fos法研究了不同日龄母鸡脑部对光照刺激的反应。对14、60、120和180日龄母鸡右眼遮光7 d后,接受20 lx的光照刺激1.5 h,暗适应1.5 h后灌流固定,取脑制作石蜡切片,采用免疫组化方法检测c-fos基因在中脑和间脑的表达。结果显示,光照刺激后在母鸡视顶盖中央灰质层(SGC),圆核(ROT),外侧膝状腹侧核(Glv),峡核大细胞部(Imc),峡核小细胞部(Ipc),室旁核(PVN),弓状核(ARC)均见有Fos样免疫反应阳性神经元,阳性神经元主要出现在脑左侧。不同日龄母鸡中脑和间脑Fos样免疫反应的程度不同。在SGC,ROT,Glv,Imc,Ipc中,14,60日龄免疫反应阳性神经元的密度最大,120,180日龄保持较高水平,300日龄明显下降。在PVN,ARC,120,180日龄表达强度最大,14,60日龄次之,300日龄最低。其中在14和60日龄与其它3个日龄组之间差异显著。表明在中枢神经内,不同日龄母鸡对光照刺激的反应不同。     

Autoregulation of enzymes by pseudosubstrate prototopes: myosin light chain kinase

The myosin light chain kinase requires calmodulin for activation. Tryptic cleavage of the enzyme generates an inactive 64-kilodalton (kD) fragment that can be further cleaved to form a constitutively active, calmodulin-independent, 61-kD fragment. Microsequencing and amino acid analysis of purified peptides after proteolysis of the 61- and 64-kD fragments were used to determine the amino-terminal and carboxyl-terminal sequences of the 64-kD fragment. Cleavage within the calmodulin-binding region at Arg505 generates the catalytically inactive 64-kD fragment, which is incapable of binding calmodulin. Further digestion removes a carboxyl-terminal fragment, including the pseudosubstrate sequence Ser484-Lys-Asp-Arg-Met-Lys-Lys-Tyr-Met- Ala-Arg-Arg-Lys-Trp-Gln-Lys-Thr-Gly-His-Ala-Val-Arg505 and results in a calmodulin-independent 61-kD fragment. Both the 61- and 64-kD fragments have the same primary amino-terminal sequences. These results provide direct support for the concept that the pseudosubstrate structure binds the active site and that the role of calmodulin is to modulate this interaction. Pseudosubstrates may be utilized in analogous ways by other allosterically regulated enzymes.     

Antigen receptor molecules: inhibition by antiserum against kappa light chains

Rabbit antiserum against mouse kappa chains, the predominant class of light chains found in mouse immunoglobulins, inhibits the immune response in vitro of mouse spleen cells to erythrocyte antigens. The inhibition becomes irreversible if the mouse spleen cells are treated briefly with both antiserum to kappa chains and complement.     

Soot in urban atmospheres: determination by an optical absorption technique

We have used the high optical absorptivity of urban and source particulates to trace their "graphitic" component. The optical absorptivity and the particulate carbon loading show a strong correlation. Analyses of the data indicate that primary soot emissions compose a major fraction of the carbonaceous aerosol and put a low limit on secondary organic material produced in correlation with the ozone concentration.