Mirror Technique Research Articles

Co-localization of vasoactive intestinal polypeptide, γ-aminobutyric acid and choline acetyltransferase in neocortical interneurons of the adult rat

Interneurons immunoreactive for vasoactive intestinal polypeptide (VIP) are integral elements of columnar organization patterns in the rat cerebral cortex. By application of the sensitive mirror technique, the co-localization of VIP with the classical inhibitory neurotransmitter γ-aminobutyric acid (GABA) and the acetylcholine-synthesizing enzyme, choline acetyltransferase (ChAT), was investigated in neocortical neurons. Furthermore, the frequency of co-localization of ChAT with GABA was determined. In a sample of 118 VIP-immunoreactive neurons, mostly from the primary somatosensory cortex, it was demonstrated that virtually all of them reveal immunoreactivity for GABA and, therefore, are to be GABAergic. Moreover, 34% of mostly bipolar, VIP-positive neurons contained ChAT and are, thus, supposedly cholinergic as well. Co-localization of VIP and ChAT varied according to cortical laminae. Finally, 88% of a total of 60 ChAT-immunoreactive neurons were also immunostained for GABA. It is concluded that almost all VIP-immunoreactive neurons and most of the cholinergic neurons in rat neocortex represent partly overlapping subpopulations of inhibitory interneurons utilizing GABA.

Real-time assay of the interaction of a GST fusion protein with a protein ligate using resonant mirror technique.

Real-time assay of the interaction of a GST fusion protein with a protein ligate using resonant mirror technique.

Low voltage built-in current sensor

A low voltage built-in current sensor (BICS) for IDDQ testing based on the bulk-driven current mirror technique is proposed. This design has a small overhead in terms of area and needs only one external power supply. Different current resolution requirements can be met by adjusting the aspect ratio of the transistors in the design. HSPICE simulation results show that high error detection speed and small performance impact on the original circuit are also achieved.

Use of two methods of analysis to estimate the annual rate of tuberculosis infection in Southern Algeria

Setting: Analysis of tuberculin skin test surveys. Objective: To estimate the annual tuberculous infection rate in Tamanrasset (southern Algeria) by applying on the one hand the classical method of the Tuberculosis Surveillance Research Unit (TSRU) of the International Union Against Tuberculosis, and on the other the study of variations of allergy published by Raj Narain et al. Methods: 3675 pupils aged 5–18 years were tested in October 1982 or November 1983; 1240 of them were tested on both occasions. The technique of the World Health Organization, with 2 TU PPD RT23 tuberculin was used by trained testers. The TSRU method was applied to the 863 children aged 5–15 years without bacille Calmette-Guerin (BCG) scar, according to three estimates of the prevalence of infection (cut-off points of the distribution of reactions of 10 mm, of 14 mm corrected by dividing by 0.82, and mirror technique with a mode of 17 mm), and to three hypotheses of the decrease in infection risk (1%, 3% and 5%). The study of variations of allergy was used in the 1240 pupils tested twice (BCG-vaccinated or not). Results: The average annual risk of tuberculous infection estimated by the TSRU method was lower than 1 % (0.5%–0.6% according to the most stringent criteria). By the method of variations of allergy, the estimated annual infection rate was 0.9%. For the latter, our results are consistent with those obtained by other researchers. Conclusions: These findings suggest that the study of variations of allergy might be a good alternative approach to estimate the annual infection rate in countries where children are BCG-vaccinated at birth, which is the case for most developing countries.

Coexistence of parvalbumin and GABA in nonpyramidal neurons of the rat entorhinal cortex

The possible coexistence of the calcium-binding protein, parvalbumin, with the major inhibitory neurotransmitter, gamma-aminobutyric acid (GABA), and its synthesizing enzyme, glutamate decar☐ylase (GAD), was studied in nonpyramidal cells of the rat medial and lateral entorhinal cortex. The material was analyzed by two different methods, the first of which was a mirror technique where the possible coexistence of two different antigens was analyzed from cells cut in half at the surface of the adjacent section. The other method consisted of analyzing double immunofluorescent-stained sections with a confocal microscope. The colocalization analysis revealed that all parvalbumin-immunoreactive neurons (minor technique n = 688 and confocal microscopy n = 644) in all layers of the medial and lateral entorhinal cortex were also immunopositive for GABA or GAD. Parvalbumin-cells made up 52% of the GABA cells in most of the layers in the medial and lateral entorhinal cortex. In layer III of the entorhinal cortex, the proportion was about 40%. Thus, parvalbumin-containing neurons in the entorhinal cortex represent a large GABAergic cell population, which is likely to play an important role in controlling both the input and the output of the entorhinal cortex.

Normal Incidence Multilayer Mirrors for Soft X-Rays.

We review first the state of the art fabrication techniques for normal incidence multilayer mirrors, and then discuss the problems such as columnar structure, thermal stability, mechanical stress, focusing properties of multilayer mirrors, film thickness distribution, and finally the applications of multilayer mirrors for the x-ray lasers and x-ray projection lithography, using mainly the data experimentally obtained.

Precise CMOS current sample/hold circuits using differential clock feedthrough attenuation techniques

New CMOS current sample/hold (CSH) circuits capable of overcoming the accuracy limitations in conventional circuits without significantly reducing operating speed are proposed and analyzed. A novel differential clock feedthrough attenuation (DCFA) technique is developed to attenuate the signal-dependent clock feedthrough errors. Unlike conventional techniques, the DCFA circuit allows the use of dynamic mirror techniques, and results in no additional finite output resistance errors or device mismatch errors. The test chip of the proposed fully differential CSH circuit with multiple outputs has been fabricated in 1.2-/spl mu/m CMOS technology. Using a single 5-V power supply, experimental results show that the signal-dependent clock feedthrough error current is less than /spl plusmn/0.4 /spl mu/A for the input currents from -550 /spl mu/A to 550 /spl mu/A. The acquisition time for a 900-/spl mu/A step transition to 0.1% settling accuracy is 150 ns. For a 410-/spl mu/A/sub p-p/ input at 250 MHz with the fabricated fully-differential CSH circuit clocked at 4 MHz, a total harmonic distortion of -60 dB, and a signal-to-noise ratio of 79 dB have been obtained. The active chip area and power consumption of the fabricated CSH circuit are 0.64 mm/sup 2/ and 20 mW, respectively. Both simulation and experimental results have successfully verified the functions and performance of the proposed CSH circuits.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A diode-pumped nonlinear mirror mode-locked Nd:YAG laser

We report on passive mode-locking of a cw diode-pumped Nd:YAG laser using the nonlinear mirror technique. The nonlinear mirror is made by a lithium triborate frequency doubling crystal and a dichroic mirror that partially transmits the fundamental frequency and totally reflects the second harmonic. The laser produces nearly transform-limited pulses of 10 ps duration and 700 mW average power, with a slope efficiency of 28%. The mode-locking is self-starting under optimized conditions. Long term stability requires accurate control of the crystal temperature.

Nonlinear mirror mode locking of a cw Nd:YLF laser

Passive mode locking of a cw lamp-pumped Nd:YLF laser with the nonlinear mirror technique is reported. Nearly transform-limited pulses of 13-ps duration and 1.5-W average power at 1.047 microm have been obtained. The nonlinear mirror consists of a lithium triborate frequency-doubling crystal and a dichroic mirror with high reflectivity for the second harmonic and lower reflectivity for the fundamental frequency. The mode-locking process is self-starting, with pulse duration and stability strongly dependent on the cavity parameters.

Analysis of the scanning electron microscope mirror image based on the dielectric surface microstructure

This paper addresses hitherto unexplained phenomena associated with the electrostatic mirror technique, such as (i) the influence of the surface microstructural parameters of a polycrystalline dielectric (e.g., alumina) on mirror images, and (ii) the distortion of mirror images. The formation of a mirror image on an as-machined alumina surface was found to be nearly impossible, but on a polished specimen, possessing low surface damages, mirror images were easily formed. A smooth and low-damage surface seems to be a prerequisite for the formation of a mirror image. The size of mirror images, observed at different locations on a polished alumina surface, was found to vary significantly, indicating that an inhomogeneous surface charging occurs in polycrystalline dielectrics. It was shown that the variation in the grain and grain boundary volumes constituting the charged region is responsible for the variation in the size of the mirror image. The distortion of the mirror images was studied using single crystal quartz specimens. The asymmetry of the equipotential boundary—caused by (i) the tilt of the crystal axis (θ≠0°) with respect to the probing electron beam, or by (ii) the asymmetrical electron interaction volume, i.e., deviation from the standard pear shape—was demonstrated to be responsible for the distortion of the mirror images.

Calretinin is present in non-pyramidal cells of the rat hippocampus—II. Co-existence with other calcium binding proteins and gaba

The possible co-existence of calretinin with other calcium binding proteins, parvalbumin and calbindin D28k, and with GABA, was studied in non-pyramidal cells of the rat dorsal hippocampal formation, using the mirror technique. The majority of the calretinin-containing neurons (83%) were found to be immunoreactive for GABA (79% in the dentate gyrus, 84% in the CA2–3, and 88% in the CA1 subfield). Most of the GABA-negative calretinin-immunoreactive neurons were located in the hilus of the dentate gyrus and in stratum lucidum of the CA3 subfield. Detailed analysis of the calretinin-immunoreactive cells of these subfields revealed that the two morphologically distinct types of calretinin neurons, i.e. the spiny and the spine-free cells, differ in their immunoreactivity for GABA. The overwhelming majority (92%) of the spine-free neurons were GABA-positive, whereas the immuno-reactivity of spiny cells was ambiguous. At the sensitivity threshold of the immunocytochemical techniques used in the present study, most of the spiny cells (89%) had to be considered as GABA-negative, although the staining intensity in their cell bodies was somewhat above background level. Colchicine treatment resulted in a degeneration of calretinin-immunoreactive neurons; therefore, its effect on the GABA content of spiny neurons could not be evaluated. Nevertheless, the observations suggest that calretinin-containing neurons are heterogeneous both morphologically and neurochemically. Examination of the co-existence of calcium binding proteins revealed that none of the hippocampal cells contained both calretinin and parvalbumin in any regions of the hippocampal formation. Some overlap was detected between the calretinin- and the calbindin D28k-containing cell populations, 5.1% of the former and 6.2% of the latter were immunoreactive for both calcium binding proteins. This may be due to a small degree of cross-reactivity of the calbindin D28k antiserum with calretinin. Thus, our results demonstrate that the majority of calretinin-immunoreactive neurons are GABAergic and represent a subpopulation of non-pyramidal cells with no or only a negligible overlap with the subpopulations containing the other calcium binding proteins, parvalbumin and calbindin.

Computational analysis of the surface permittivity and charging of dielectrics with the SEM-mirror technique

Computational analysis based on the charge simulation method (CSM) is used to predict the electric potential distribution produced by charges implanted within the surface layer of a solid dielectric. The potential distribution thus obtained is used to match the experimental distribution using the scanning electron microscope (SEM) mirror technique. Using an optimization iteration process, a comparison is obtained for quartz, alumina, and yttria. The computational analysis assumes a surface layer with a permittivity higher than that of the bulk. The justification for this assumption is discussed. The electric potential distribution produced by a surface with increased surface defects, as determined by the SEM mirror technique, indicates a surface with a higher permittivity. It is also shown that the ability of such a surface to store charges is decreased. The results are consistent with physical models based on band structure (or trapping energy) considerations. >

Ultrastructural demonstration of synaptic connections between calcitonin gene-related peptide immunoreactive axons and dynorphin A(1–8) immunoreactive dorsal horn neurons in a rat model of peripheral inflammation and hyperalgesia

Synaptic contact between dynorphin A(1–8)-like immunoreactive lamina V spinal neurons and calcitonin gene-related peptide-like immunoreactive axon terminals was demonstrated using the immuno-electron microscopic mirror technique in a rat model of peripheral inflammation and hyperalgesia. Adjacent tissue sections were immunocytochemically labeled for either dynorphin A(1–8) or calcitonin gene-related peptide and examined at the electron microscopic level for the presence of synaptic contacts. The results suggest that some opioid neurons which exhibit a dynamic increase in dynorphin peptide associated with peripheral inflammation and hyperalgesia receive direct monosynaptic input from presumptive nociceptive primary afferents.

Variables in Vocal Cord Injection: A Guide for the Occasional Operator

Robert B. Lewy, MD, and John P. Leontti, MD, reported their observations in performing 296 vocal cord injection procedures over a 24-year period. Their report, presented at the Middle Section meeting of the Triological Society, Ann Arbor, Mich, emphasized the importance of evaluating candidates for vocal cord injection with respect to anatomic variations, surgical technique, and perioperative care. The authors stated that the results with Teflon injection are better when flat, nonatrophic vocal cords are injected at their central portion and that thin atrophic cord injections should be angled outward toward the thyroid cartilage ala. Variable results can be expected with Teflon injection of asymmetric vocal cords. The authors emphasize the importance of not distorting the glottis with the laryngoscope during the injection procedure, although accurate placement for maximum visualization is essential. They found no advantage to microscopic laryngoscopy and suggested that the indirect mirror technique should be reserved for

ChemInform Abstract: Gas‐Phase Coupling of Methyl Radicals During the Catalytic Partial Oxidation of Methane

It is generally accepted that the initial step in the catalytic oxidative coupling of methane involves the homolytic cleavage of a C-H bond. This results in the formation of surface OH species and CH/sub 3//sup ./ radicals which may undergo coupling to form ethane. A question arises as to whether the methyl radical coupling occurs on the surface or in the gas phase. Keller and Bhasin proposed a mechanism for the catalytic oxidative coupling of CH/sub 4/ in which the formation of C/sub 2/H/sub 6/ resulted from the surface coupling of adsorbed CH/sub 3/* radicals. In contrast to this mechanism, Lunsford and co-workers proposed that a homogeneous gas-phase coupling of CH/sub 3/* radicals, formed by the surface abstraction of H-atoms from CH/sub 4/, was the primary pathway for C/sub 2/H/sub 6/ formation. Evidence for the existence of gas-phase CH/sub 3//sup ./ radicals during the oxidative coupling of CH/sub 4/ has been obtained by Driscoll et al. with the use of a matrix isolation electron spin resonance (MIESA) technique and, more recently, by Jones et al. with use of the Paneth lead mirror technique. The modeling studies of Labinger and Ott and of Kimble and Kolts also support the role ofmore » gas-phase CH/sub 3//sup ./ radicals; however, the actual significance of these radicals in the formation of C/sub 2/H/sub 6/ has not been experimentally proven. In this communication of a lower limit for the rate of gas-phase CH/sub 3/* radical formation over a lithium-promoted MgO catalysts has been determined and this result is compared with the overall rate of C/sub 2/H/sub 6/ formation.« less

Gas-phase coupling of methyl radicals during the catalytic partial oxidation of methane

It is generally accepted that the initial step in the catalytic oxidative coupling of methane involves the homolytic cleavage of a C-H bond. This results in the formation of surface OH species and CH/sub 3//sup ./ radicals which may undergo coupling to form ethane. A question arises as to whether the methyl radical coupling occurs on the surface or in the gas phase. Keller and Bhasin proposed a mechanism for the catalytic oxidative coupling of CH/sub 4/ in which the formation of C/sub 2/H/sub 6/ resulted from the surface coupling of adsorbed CH/sub 3/* radicals. In contrast to this mechanism, Lunsford and co-workers proposed that a homogeneous gas-phase coupling of CH/sub 3/* radicals, formed by the surface abstraction of H-atoms from CH/sub 4/, was the primary pathway for C/sub 2/H/sub 6/ formation. Evidence for the existence of gas-phase CH/sub 3//sup ./ radicals during the oxidative coupling of CH/sub 4/ has been obtained by Driscoll et al. with the use of a matrix isolation electron spin resonance (MIESA) technique and, more recently, by Jones et al. with use of the Paneth lead mirror technique. The modeling studies of Labinger and Ott and of Kimble and Kolts also support the role ofmore » gas-phase CH/sub 3//sup ./ radicals; however, the actual significance of these radicals in the formation of C/sub 2/H/sub 6/ has not been experimentally proven. In this communication of a lower limit for the rate of gas-phase CH/sub 3/* radical formation over a lithium-promoted MgO catalysts has been determined and this result is compared with the overall rate of C/sub 2/H/sub 6/ formation.« less

Ultrarapid cooling and molecular distillation drying for sample preparation

The efficacy of electron microscopy as a tool to answer biochemical structure-function questions relates directly to the changes induced during sample preparation. Limitations of conventional methods include: slow penetration and crosslinking by fixative, aqueous extraction, solvent extraction and chemical modification by crosslinking agent. Advantages include: stability of resin embedded sections and the opportunity for repeated analysis. The aim of this study has been to develop and apply a technique of sample preparation which minimizes the limitations while maintaining the advantages of a resin embedded section. The method is divided into four components i.e., ultrarapid cooling, molecular distillation drying, vapor phase osmication and direct resin infiltration in vacuo.Ultrarapid cooling was obtained by the use of the metal mirror technique. Tissue samples (1mm3) or cultured cells grown on Therminox plastic were mounted on sample holders designed to minimize compression.

Neostriatal cholinergic neurons receive direct synaptic inputs from dopaminergic axons

We used an electron microscopic ‘mirror technique’ to determine whether cholinergic neurons are in direct synaptic contact with dopaminergic axons in the rat neostriatum. Tyrosine hydroxylase-immunoreactive axons make synaptic contacts with the somata and proximal dendrites of large choline acetyltransferase-immunoreactive striatal neurons which are thought to be interneurons. This provides morphological evidence that nigrostriatal dopaminergic neurons can influence monosynaptically the striatal cholinergic neurons.

The paracrystalline structure of an insect rhabdomere (Calliphora erythrocephala)

By use of a modified fixation technique, the receptor cells of the compound eye of the blowfly Calliphora erythrocephala were found to contain a regular, paracrystalline array of alternating rows of hexagonally shaped microvilli. The receptor cells R1 to R6 have a cell-specific number of microvilli per row in a cross section. Every microvillus has a filament cluster connecting the axial skeleton with the microvillar membrane. This cluster is preferentially right-left oriented relative to the longitudinal axis of the microvillar array. Three adjacent microvilli are interconnected by an electron-dense substance. A mirroring technique indicated that this intermicrovillar structure consists of three subunits, although these subunits could not be conclusively demonstrated by classical densitometry or image subtraction techniques. The electron-dense substance can be seen in all cross sections of the proximal and distal parts of the microvilli. They are cylindrical structures separating the microvilli along their entire length. It is suggested that these cylindrical aggregates contain an enzymatic complex separating the rhodopsin-containing microvillar membrane into six compartments.

Dopaminergic axons directly make synapses with GABAergic neurons in the rat neostriatum

We examined with an electron microscopic ‘mirror technique’ whether glutamic acid decar☐ylase-immunoreactive (GAD-IR) neurons are in direct synaptic contact with tyrosine hydroxylase-immunoreactive (TH-IR) axons in the rat neostriatum. Three types of GAD-IR neurons were identified in the nucleus caudatus putamen based upon their size and ultrastructural characteristics. These were medium spiny, medium aspiny and large cells. All types of GAD-IR neurons made synaptic contact with TH-IR axonal boutons at least on perikarya and proximal dendrites. This provides ultrastructural evidence for catecholaminergic, presumably, nigrostriatal dopaminergic inputs to both long- and short-axon neurons most probably containing GABA.