Fabrication and characterization of RF nanoantenna on a nanoliter-scale 3D microcontainer.

We report the design and fabrication of a nanoantenna structure on the surface of a 3D nanoliter-scale container for the development of communicable nanoliter-scale chemical delivery systems. The porous container was self-assembled, after which the nanoantenna was fabricated on the top of the microcontainer using focused ion beam (FIB) ion-induced metal deposition. The nanoantenna was structured as a rectangular metal coil composed of platinum (Pt) nanowires (70 nm in width). The response of the nanoantenna structure was simulated using finite element software and showed a strong resonant feature at 10.8 GHz, which was confirmed by high frequency measurements.

Expression of axon guidance molecules and their related genes during development and sexual differentiation of the olfactory bulb in rats.

Axon guidance molecules and related proteins such as semaphorin 3A, neuropilin-1, plexin-1, netrin-1, growth-associated protein, olfactory marker protein, cypin and collapsin response mediator proteins guide the development of neural circuits in the olfactory bulb. In this study, transcriptions of these genes were examined in the olfactory bulb of female, male and neonatal testosterone propionate-treated female rats at the ages of 2, 5, 10, 15, 20, 25, 30 and 45 days. The semaphorin 3A, neuropilin-1, growth-associated protein and collapsin response mediator protein 1-5 genes were expressed significantly higher during the early development stages than in adulthood while the opposite is true for the olfactory marker protein. The expression profile of cypin and netrin-1 was relatively constant through development. A late effect of the neonatal testosterone propionate treatment on netrin-1, growth-associated protein, olfactory marker protein, collapsin response mediator proteins 1, 3, 4 and cypin gene expression was observed. The expression profiles of collapsin response mediator proteins and their related genes in the developing olfactory bulb confirmed most studies on the relationship between collapsin response mediator proteins and development in the brain. Sex differences of semaphorin 3A, neuropilin-1 as well as collapsin response mediator protein 3 at the early development stage and the late effect of neonatal testosterone propionate treatment on the expressions of netrin-1, growth-associated marker protein, cypin and collapsin response mediator proteins 1, 3 and 5 genes may indicate a possible role of these molecules on sexual differentiation of the olfactory bulb.

Effects of neonatal hypothyroidism on the expressions of growth cone proteins and axon guidance molecules related genes in the hippocampus.

During critical periods of development, hypothyroidism causes abnormalities of the central nervous system such as incomplete maturation of neuronal and glial cells, reduction in synaptic densities and myelin deficits. In this study expression of development regulated genes, ie transcription of beta-actin, sema 3F, CRMP 1 to 4, GAP-43, G alpha o1, G alpha o2 and translation of beta-actin, G alpha o, G alpha o1, CRMP-2, CRMP-4 genes were examined in the hippocampus of neonatal methimazole induced hypothyroid rats at the age of day 16. All CRMPs mRNA levels were significantly higher in the hypothyroid rats. Significant higher CRMP-2 protein but not CRMP-4 protein was found in the hypothyroid rats. The neonatal experimental hypothyroid states did not affect the protein levels of beta-actin but up-regulate its mRNA. Transcription of CRMP 1 to 4, GAP-43, G alpha o1 but not G alpha o2 and sema 3F was altered by the neonatal treatment. The only sex difference in gene expression was found in the transcription of CRMP-2 gene.

Reduced responsiveness of touch (SA I) receptors in the cat following close arterial infusion of neomycin.

Electrophysiological recordings were made from afferent nerve fibres supplying slowly adapting type I (SA I) cutaneous mechano-receptors in the cat during application of mechanical stimuli (20 mN constant force, 0.2 s rise time and 2 s plateau phase, every 30 s). Close arterial infusion of neomycin (2.5 mg/min for 5 min) strongly depressed the responsiveness of SA I receptors. A direct effect on the receptor is thought to be the mode of action.

Gene expressions during the development and sexual differentiation of the olfactory bulb in rats.

In this study, expressions of cell-cycle-related genes: p53, retinoblastoma (Rb), p21, bcl-2(alpha), bcl-2(beta); protooncogene c-ski; glial cell marker protein gene S100beta; neurotransmitter gene, substance P and sexual-differentiation-related genes, androgen receptor (AR) and estrogen receptor beta (ER(beta)), are studied in the olfactory bulb of groups of both six female and six male rats at the ages of 3, 10, 20 and 40 days. Expressions of housekeeping genes such as beta-actin, cyclophilin and proliferating cell nuclear antigens (PCNA) are determined using reverse transcription polymerase chain reaction (RT-PCR) for the correction of unequal amount of cDNA added into the samples. Using labeled 32P-dCTP and Phosphorimager technology, relative abundance of radioactivities of the PCR products is obtained by dividing the radioactivity of each individual sample by the corresponding radioactivities of different housekeeping genes. Data evaluated by Two-way ANOVA indicate that only the bcl-2(alpha) gene expression is affected significantly by age, sex and their interactions no matter which of the three housekeeping genes is used for correction. When beta-actin was used for corrections, effects of age but not sex were found in the expressions of p53, Rb, p21, AR, ER(beta), substance P and S100beta genes, but not in bcl-2(beta), c-ski, cyclophilin and PCNA genes. While cyclophilin was used for corrections, only the p53, Rb, AR, ER(beta), substance P and S100beta but not the bcl-2(beta), p21, c-ski, PCNA and beta-actin genes are affected by age. They are all not influenced by sex of the animals. Only the AR, ER(beta) and S100beta genes are age-dependent when PCNA was used for the correction. The other gene expressions are not altered by sex, while the interactions of age and sex were found to be significantly affecting the bcl-2(beta) gene expression. Conclusively, developmental changes of the p53, Rb, AR, ER(beta), substance P and S100beta genes expressions are quite evidenced while only the bcl-2(alpha) gene seems to change significantly during the sexual differentiation of olfactory bulb in rats.

Expressions of putative neurotransmitters and neuronal growth related genes in Merkel cell-neurite complexes of the rats.

Reverse transcription-polymerase chain reaction using 32P-labeled dCTP with specific primers for putative neurotransmitters related and neuronal growth-related genes (GAP-43, NGF and BDNF) were used to search for evidence of such substances in the Merkel cell. Merkel cell samples were made from sinus hairs in the facial skin of rats. The relative amount of mRNA in a tissue sample concentrated in Merkel cells was compared semiquantitatively to that from nearby tissue without Merkel cells. mRNAs for VIP, tyrosine hydroxylase, substance P were found in higher concentration in Merkel cells than in control tissues. mRNA for genes encoding pro-enkephalin, GAP-43, CGRP, NGF and BDNF were detected in the Merkel cell samples at concentration statistically equivalent to those found in the control tissues. It was concluded that the relative concentration of mRNAs for VIP, tyrosine hydroxylase and substance P is consistent with the possibility that Merkel cell acts as a possible transduction element in mechanical excitation of sense organs in which Merkel cells are present.

Metalloorganic solution deposition of ferroelectric PZT films.

The metallo-organic solution deposition (MOSD or sol-gel) technique can be used for preparing lead zirconate titanate (PZT) ceramics with a wide range of compositions and crystal structures for electrooptical applications. Film morphology is affected by the stoichiometry of the film, hydrolysis and polymerization of the sol-gel solution, and thermal treatment of the deposited material. The lattice parameter decreases with the amount of titanium in the PZT, in agreement with ceramic data. A slight initial excess of lead in the coating solution is found to improve film morphology. Unlike traditional powder ceramic processing techniques, MOSD permits the growth of small uniform grains that are conducive to achieving consistent electronic and optical properties. Results show that the properties of films prepared by the MOSD process can be tailored to meet the needs of device applications.

Acute effects of neomycin on slowly adapting type I and type II cutaneous mechanoreceptors in the anaesthetized cat and rat.

1. Slowly adapting type I (SAI) and type II (SAII) mechanoreceptors in the skin were studied in anaesthetized cats and rats employing mechanical stimuli every 30 s. Individual stimuli rose within 200 ms to a plateau force which was kept constant through a feedback control unit for 2000 ms. 2. In cats, close arterial infusion of neomycin (2.5 mg/min) as sulphate was given through a side branch into the femoral blood stream for 5, 10 or 20 min at a rate of 0.025 ml/min. At other times saline was infused at the same rate. 3. After 20 min of neomycin infusion (total 50 mg) nervous discharge of cat SAI receptors was suppressed to about 30% of the control responses before neomycin infusion. Nervous responses were reduced more profoundly during the plateau phase of stimulation than during the dynamic phase. The interspike interval histogram was severely distorted. 4. In contrast, cat SAII receptors maintained about 70% of their control response after 20 min of neomycin infusion. The interspike interval histogram showed an orderly shift towards longer intervals maintaining its normal shape. 5. In rats, intradermal microinfusion of neomycin (30 micrograms/min) through a glass micropipette into the immediate vicinity of the receptor under investigation resulted in severe transient suppression of SAI receptor responses to about 10% of the control level. Receptor responses recovered almost completely about 1 h after the end of neomycin application. 6. It is concluded that the observed differences between the two types of slowly adapting mechanoreceptors are consistent with the hypothesis that the SAI receptor functions as a secondary sensory receptor, with a synaptic link between the Merkel cell and the primary afferent neurone.

Mechanical properties of skin and responsiveness of slowly adapting type I mechanoreceptors in rats at different ages.

Slowly adapting type I (s.a. I) cutaneous mechanoreceptors were studied in young (3-4 months old) and adult (9-11 months old) rats. Trains of thirty repetitive mechanical stimuli with 0.1 s rise time, 1.9 s plateau phase, and 0.7 s interstimulus interval were applied. A feed-back mechanism maintained the force of stimulation at 20 mN during the plateau phases of stimuli and the contact force between stimuli at 0.5 mN. During the first few stimuli in a train residual indentation at contact force increased rapidly. Maximal indentation required to maintain the force of stimulation of 20 mN increased as well but to a smaller extent. Thus, the stroke amplitudes of individual stimuli decreased with increasing stimulus number. All displacement values in the group of adult rats were consistently reduced to 62 +/- 3% of the respective values in the group of young rats, indicating a linear decrease in skin compliance in the force range of 0.5-20 mN. Nervous responses to individual stimuli decreased from about 200 impulses for stimulus number 1 to about 60 impulses for stimulus number 30. Significant differences in the number of impulses between young and adult rats were observed from stimulus number 9 to number 16 only. It is concluded that the design of the s.a. I receptor allows maintained high tactile sensitivity in response to force-related stimuli irrespective of age-induced changes in mechanical properties of the skin and underlying tissues.

Thyroid and skin-shedding in the rat snake (Ptyas korros).

Epidermal-thyroid relationships were studied in thyroidectomized (Tx) Ptyas korros kept at 23 degrees C by observing changes in shedding frequency (SF), body weight, oxygen consumption rate (OCR), and postsurgical survival. Tx animals showed increased SFs but lost weight and eventually died, as did Tx animals receiving 3-mono-iodotyrosine injections. However, injections of 3, 5-diiodothyronine inhibited shedding and the animals survived longer. OCRs were similar in all control and experimental groups. It is concluded that among thyroid secretions, only iodothyronines inhibit shedding. Snake shedding is concluded not to reflect general metabolic status as it does in lizards.

Responsiveness and ultrastructure of slowly adapting type I cutaneous mechanoreceptors in vitamin A deficient rats.

Single-unit recordings were made from afferent nerve fibres supplying slowly adapting type I (s.a. I) cutaneous mechanoreceptors in anaesthetized vitamin A deficient and control rats. Trains of thirty repetitive mechanical stimuli with 0.1 s rise time, 1.9 s plateau phase, and 0.7 s interstimulus interval were applied. A feed-back mechanism maintained the force of stimulation at 20 mN during the plateau phases and the contact force between stimuli at 0.5 mN. All displacement values in the group of vitamin A deficient rats were significantly larger than the corresponding control values. Residual indentations were increased by 70-100% while maximal indentations were only about 40% higher. These results indicate a non-linear increase in compliance of the skin and underlying tissues. S.a. I receptors were found to be significantly less responsive in vitamin A deficient animals. Mean numbers of impulses were about 25% lower in the vitamin A deficient group than in controls throughout the entire train of thirty stimuli. In vitamin A deficient rats, Merkel cells and adjoining nerve terminals showed signs of degeneration of a variety of cell organelles, particularly the mitochondria. Degenerative changes induced by vitamin A deficiency especially in the Merkel cells appeared to be a major cause of the reduction of responsiveness in s.a. I receptors.