LIPSS-based functional surfaces produced by multi-beam nanostructuring with 2601 beams and real-time thermal processes measurement.

A unique combination of the ultrashort high-energy pulsed laser system with exceptional beam quality and a novel Diffractive Optical Element (DOE) enables simultaneous production of 2601 spots organized in the square-shaped 1 × 1 mm matrix in less than 0.01 ms. By adjusting the laser and processing parameters each spot can contain Laser Induced Periodic Surface Structures (LIPSS, ripples), including high-spatial frequency LIPSS (HFSL) and low-spatial frequency LIPSS (LSFL). DOE placed before galvanometric scanner allows easy integration and stitching of the pattern over larger areas. In addition, the LIPSS formation was monitored for the first time using fast infrared radiometry for verification of real-time quality control possibilities. During the LIPSS fabrication, solidification plateaus were observed after each laser pulse, which enables process control by monitoring heat accumulation or plateau length using a new signal derivation approach. Analysis of solidification plateaus after each laser pulse enabled dynamic calibration of the measurement. Heat accumulation temperatures from 200 to 1000 °C were observed from measurement and compared to the theoretical model. The temperature measurements revealed interesting changes in the physics of the laser ablation process. Moreover, the highest throughput on the area of 40 × 40 mm reached 1910 cm2/min, which is the highest demonstrated throughput of LIPSS nanostructuring, to the best of our knowledge. Thus, showing great potential for the efficient production of LIPSS-based functional surfaces which can be used to improve surface mechanical, biological or optical properties.

Analysis of short wavelength infrared radiation during laser welding of plastics.

In this paper, a new measurement system and a new approach in calculation for infrared (IR) radiation investigation in quasi-simultaneous transmission laser welding of plastics are presented. The measurement system is based on a MW/SWIR (medium-wave/short-wave IR) camera and optical filters narrowing the spectral region to SWIR. The measured signals contain radiation from the melted zone in between the semitransparent and absorbing polymers, as well as radiation from the surface and interior of the semitransparent polymer. The new calculation approach was developed to distinguish between these signals. It is based on simplification of the process to two places with two temperatures (surface and molten interface) and knowledge of the spectral optical properties of the material, filters, and camera response. The results of measurement and calculation for three different optical filters and polyoxymethylene samples with two thicknesses are shown and discussed. Good agreement is obtained for the calculation variant using normal transmissivity of the semitransparent polymer.

Optical layer development for thin films thermal conductivity measurement by pulsed photothermal radiometry.

Measurement of thermal conductivity and volumetric specific heat of optically transparent thin films presents a challenge for optical-based measurement methods like pulsed photothermal radiometry. We present two approaches: (i) addition of an opaque optical layer to the surface and (ii) approximate correction of the mathematical model to incorporate semitransparency of the film. Different single layer and multilayer additive optical layers were tested. The materials of the optical layers were chosen according to analysis and measurement of their optical properties: emissivity and absorption coefficient. Presented are thermal properties' measurement results for 6 different thin films with wide range of thermal conductivity in three configurations of surface: as deposited, added Ti layer, and added Ti/TiAlSiN layer. Measurements were done in dependence on temperature from room temperature to 500 °C. The obtained thermal effusivity evolution in time after the laser pulse shows different effects of the surface layers: apparent effusivity change and time delay. Suitability of different measurement configurations is discussed and results of high temperature testing of different optical layers are presented.

Measurement of thermal properties of thin films up to high temperatures--pulsed photothermal radiometry system and Si-B-C-N films.

A new arrangement of two-detector pulsed photothermal radiometry measurement system has been developed enabling temperature dependence measurement of thermal properties of thin films up to high temperatures. Only a few methods are available in this temperature range for thin films' thermal properties investigation, but there is a need for their knowledge in the fields of high-temperature electronics and high-speed machining. The present system enables simultaneous determination of the thin film effusivity, thermal conductivity, and volumetric specific heat in the temperature range from room temperature to 600 °C. The samples are placed in a vacuum chamber. The temperatures in the system were verified by an independent measurement and the system was tested on known bulk samples. Advantages and shortcomings of the method when used at higher temperatures and in the vacuum are described and discussed. Furthermore, Si-B-C-N thin films were studied. These amorphous ceramic materials possess an interesting set of mechanical and thermal properties. In particular, the films of the investigated chemical composition exhibit an excellent thermal stability at temperatures of up to 1700 °C. In the studied temperature range, from 20 to 600 °C, the thermal conductivity increased with increasing temperature from 1.72 to 1.89 W m(-1) K(-1) and volumetric specific heat increased from 2.65 to 3.76 × 10(6) J m(-3) K(-1).

Odor discrimination and dominance in male domestic guinea pigs.

Do male guinea pigs (Cavia porcellus), with established positions in social dominance hierarchies, discriminate subordinate and dominant animals based upon odor cues from the perineal sac glandular complex? Six groups of three or four males were tested first to establish within-group dominance status and second for responses to cotton swabs that had been wiped with the perineal sac glandular complex of other males in the group. There was a significant (P < 0.05) linear relationship between aggressive responses to the cotton swabs and dominance ranks of the males (y = -0.16x + 0.86). Dominance may influence sebum production in the perineal sac glandular complex of guinea pigs via a mechanism involving androgens. Discrimination of dominance status could function in terms of male spatial relations, avoidance of areas inhabited by dominant individuals, and possibly in terms of female mate selection.

Fate of stored secretion following ligation of the seminal vesicle-coagulating gland in the rat.

Unilateral ligation of the seminal vesicle-coagulating gland complex in castrated and testes intact sexually mature rats resulted in a significant asymmetry in weight after 14 days, with ligated glands heavier in both groups. Differences in weight between glands resulted from ligation, and the primary route by which stored secretion is eliminated from these glands is by spontaneous ejaculation rather than resorption via the glandular epithelia.

Boar sperm cytoplasmic droplets: their ultrastructure, their numbers in the epididymis and at ejaculation and their removal during isolation of sperm plasma membranes.

Cytoplasmic droplets of the boar are progressively lost from the flagellum of boar spermatozoa during epididymal transit, at ejaculation and during the nitrogen cavitation technique for isolation of plasma membranes. Apparently very fragile, these structures are broken up in the fluids of the reproductive tract and in the buffer used during the nitrogen cavitation procedure. The maximal potential contamination of cytoplasmic droplet internal vesicular membranes in plasma membrane fractions was determined to be 2.2% of the entire membrane surface area collected. The highly sensitive silver-stained, two-dimensional (2-D) polyacrylamide (PAGE) gels of boar sperm plasma membranes did not reveal cytoplasmic droplet, internal membrane, marker polypeptides, further demonstrating the high purity of plasma membrane preparations. In addition, freeze-fracture demonstrates that the internal membranes of the cytoplasmic droplet show few intramembranous particles and these may contribute little protein to plasma membrane preparations. The presence of two forms of vesicular elements in boar sperm cytoplasmic droplets (typical vesicles and collapsed vesicles) is described.

Elimination of stored material from the seminal vesicles of the guinea pig following castration.

Experiments were carried out to determine what factors are involved in the disappearance of stored secretion from the seminal vesicles of the guinea pig and in the concurrent decline in weight of these glands following castration. Seminal vesicles of sexually mature males were unilaterally ligated, and the males were either castrated or left testes intact for a 14-day period. At necropsy, the seminal vesicles were removed and weighed, and biopsies were collected for histological inspection. The weight of nonligated vesicles from castrated males declined to less than half that of ligated sides. In testes-intact males, the weight of ligated vesicles was nearly double that of nonligated vesicles. Epithelial cell heights remained unchanged during the study. The rapid decline in weight of the guinea pig seminal vesicles following castration was attributed to the elimination of stored secretion by way of the urethra rather than by absorption.

Spermatophores of the salamander Ambystoma texanum.

Living spermatozoa were observed in freshly deposited spermatophores and in fluid from vasa deferentia. In the distal, but not proximal, vas deferens spermatozoa moved together in whorls with heads and tails in alignment. Around the entire periphery of the spermatophore cap, similar slowly undulating groups of spermatozoa had their heads aligned and directed outward. Over time, some individual spermatozoa left the cap of the spermatophore and moved into the surrounding water (cap deterioration). Microscopical observations were made on spermatophore squashes and paraffin sections of spermatophores and vasa deferentia. Spermatozoa around the periphery of the cap were underlain by a PAS-positive membrane-like material. Cytoplasmic droplets, which were attached to spermatozoan necks in the vas deferens, were accumulated in the center of the spermatophore cap deep to the PAS-positive membrane. Spermatophore stalks were strongly PAS and Alcian blue positive and showed positive reaction for RNA. Tests for lipids and proteins were negative in the whole spermatophore. Electron microscopic observations showed the stalk of the spermatophore to be composed of rounded 'balls' of fibrous material. At the juncture of the stalk and cap a less dense fibrous material impacted the stalk enclosing many sperm tails and some heads and, although no attachment devices were visualized, the sperm were closely apposed to this material as was the spermatophore stalk. This finely filamentous material encircled the cap and was more prominent in some regions than others. The PAS-positive material detected with the light microscope was also observed with the electron microscope. It was circumferentially oriented and was composed of 200 A packed filamentous densities. Sperm heads and tails were found lying external to the membrane, whereas only tails and cytoplasmic droplets occupied the core of the spermatophore. Cytoplasmic droplets were usually free of the sperm tail and contained membranous sacs and two types of nuage material.

Fertility of spermatozoa from the excurrent ducts of the guinea-pig.

Guinea-pigs were inseminated with spermatozoa from the vas deferens, where they are characteristically arranged in rouleaux, or from that part of the epididymis where rouleaux are infrequent. Fertility was much reduced in the 16 females inseminated with a suspension of single spermatozoa: only 4 became pregnant (compared with 10/11 controls) and all these had had some (0.5-0.75%) rouleaux in the insemination suspension. It is concluded that rouleau formation is indicative of physiological as well as morphological maturity.

Paraformaldehyde-induced fluorescence as a histochemical test for 5-hydroxytryptamine in the epididymis of the opossum.

Epididymides of four opossums were tested histochemically for the presence of 5-hydroxytryptamine (5-HT). In addition, testes and epididymides of two opossums were analysed biochemically for the same substance. Biochemical analysis revealed a high concentration of 5-HT in the epididymis, while the amount in the testis proved to be insignificant. Fluorescence microscopy gave positive results in the apical portion of the epithelium. There was also fluorescence in the connective tissue in general, in mast cells, and in a thick subepithelial band in particular. Following treatment with 2% sodium borohydride in 1,2-propanediol for 15 minutes, the fluorescence of mast cells was removed, while there was a slight reduction in epithelial fluorescence and that in the subepithelial band and other connective tissue. The subepithelial band stained metachromatically with azure B, and this staining characteristic was removed by treatment with RNAse. Feulgen reaction revealed elongate nuclei in the band. It would seem that the 5-HT is located in both the mast cells and the epithelium. It seemed to be also present in the subepithelial band, but because of strong autofluorescence it is difficult to demonstrate. At the present time the function of 5-HT in the opossum epididymis is unknown, and is under further investigation.

Rouleau formation and fertility of spermatozoa in guinea pigs treated with cyproterone acetate.

The effects of cyproterone acetate (CA) on fertility of spermatozoa and rouleau formation were investigated in male guinea pigs. Twelve of 15 matings during CA treatment resulted in pregnancy even when rouleaux were absent in ejaculates, indicating that the rouleau condition is not necessary for the fertilizing ability of guinea pig spermatozoa. Examination of epididymides and vasa deferentia revealed that rouleaux diminished progressively with treatment time and were absent in the excurrent ducts of all males during the eighth and ninth weeks of treatment. Following a latent period after treatment, rouleaux were first noted in a specific epididymal region and were present throughout the distal excurrent ducts and ejaculates by 6 wk posttreatment. This sequence of rouleau loss and reappearance in the excurrent ducts suggests that rouleau formation is dependent on a regional epididymal influence that requires androgens. Spermatogenesis was not arrested; however, seminal vesicle and body weights were reduced in treated males.

Morphology and fertility of guinea pig spermatozoa aged in vivo.

The morphology and fertility of spermatozoa from vasa deferentia of guinea pigs were observed following hemicastration or castration for approximately 40 days. The morphology of these aged sperm was studied from living and fixed preparations. Fertilizing ability was assayed by artificial insemination of estrous females and subsequent counting of embryos. Spermatozoa underwent morphological changes including dissociation of rouleaux, curving of tails, and loss of acrosomes; physiological changes included a decline in the number of sperm with progressive motility and increased numbers of immotile spermatozoa with time after the operations. The fertilizing capacity of spermatozoa was maintained for approximately 30 days in both groups. However, sperm from one of the hemicastrated males resulted in conception 36 days postoperation. The data suggest that the loss of motility and decline in fertilizing ability were the result of spermatozoa senescence rather than testicular androgen deficiency.

The role of the copulatory plug in reproduction of the guinea pig.

Two methods of artificial insemination and removal of copulatory plugs were used to investigate the role of the plug in the guinea pig. In addition, the effectiveness of the copulatory plug in blocking the passage of spermatozoa from the second mating was tested in albino females, where coat color was used as a genetic marker. Thirteen female guinea pigs that were either in proestrus, estrus, or metestrus, and inseminated with freshly collected copulatory plugs containing living spermatozoa, did not conceive. In a group of six females from which the copulatory plus was immediately removed, five conceived. Of nine estrous females artificially inseminated, five conceived. In five albino females, copulatory plugs from albino males completely blocked spermatozoa deposited by colored males, and 20 offspring, all albino were born. In a second group of four albino females where the plugs of albino males were removed prior to copulation with colored males, resulting litters were sired by either male or a combination of both males.

A new castration technic in the guinea pig.

A castration technic was perfected for removing seminiferous tubules and Leydig cells from the tunica albuginea, leaving the epididymis and its nerve and vascular supplies intact. There was a significant decrease in seminal vesicle weight in 15 guinea pigs castrated by this new procedure, indicating that the testicular androgen source was removed during castration. Spermatozoa remained motile in the ductus deferens of 18 animals that had been castrated for periods ranging from 7-70 da. The longevity of spermatozoa in the excurrent ducts was attributed to minimal trauma and damage to the ducts and their vascular and nvere supplies using this new technic.