Comb Response Research Articles

Generation and Evolution of Phononic Frequency Combs via Coherent Energy Transfer between Mechanical Modes

Phononic frequency combs represent the mechanical analog of optical frequency combs. Several independent experimental studies have demonstrated the onset and evolution frequency comb response in a variety of micro- and nanoelectromechanical devices in recent years. A theoretical basis for exploring and understanding the conditions for comb generation and evolution with varying driving parameters is essential to enable future practical applications. Here, we present the comparison between modeling and experimental results on the generation and evolution mechanism of phononic frequency combs in a nonlinear micromechanical resonator from the perspective of coherent energy transfer between two mechanical modes. Phononic frequency combs emerge in a strong coupling regime involving nonlinear resonances when the amplitudes and phases of two coupled mechanical modes are modulated via coherent energy transfer. The spacing and number of comb teeth can be analytically estimated based on modeling the nature of the interaction of the coupled modes under the specified driving conditions. As the driving conditions are varied, the phononic frequency comb evolves into different forms and a phenomenological model for the system is established to accurately predict the evolution of phononic frequency combs. The alignment between experiment and model provides a basis for the engineering of this phenomenon in future device applications.

Design and Demonstration of Apodized Comb Filters on SOI

We report on the design, modeling, and characterization of apodized comb filters in the silicon-on-insulator platform. These devices are based on sampled gratings, wherein the comb response is generated by a convolution of a regular grating by a predetermined periodic sampling function. We show that dual and complementary apodization of the etch depth in the marks and spaces ensures a near-zero dc index change over the length of the device and avoids the unwanted sidelobes obtained in a single apodized device. Comb filters with a 40-dB side-mode suppression ratio, a 92-GHz clear bandwidth, 200-GHz channel spacing, and a 120-dB/dec rolloff have been theoretically proposed. An experimental demonstration of the fabricated devices is also presented, and the performance is compared with the numerical simulations.

Integrated Fabry-Perot Comb Filters for Optical Space Switching

The first implementation of an integrated filter for optical space switching based on coupled Fabry-Perot cavities built in a planar waveguide and working at oblique incidence is presented in this paper. Parabolic mirrors are used to collimate and direct light into a filter defined by deep etching in a GaAs waveguide and formed of four high-order cavities that provide a 200 GHz comb response. The filter has a theoretical passband bandwidth of more than 50 GHz and allows the switch to work over an entire wavelength band. It was possible to contain 50 channels of the International Telecommunication Union 100 GHz grid within the filter response. Bit error rate tests at 10 Gb/s were performed to evaluate the switch power penalty. To assess the scalability of this switch design, crossbar and shuffle Benes¿ layout for devices with 2-16 ports were optimized. The dominating factor that limits the minimization of a switch fabric area is the beam waist required to avoid distortion by the filters.

Discovery of solar-like oscillations in the red giantε Ophiuchi

We present the discovery of solar-like oscillations in time-series of the G9.5 red giant \varepsilon Ophiuchi. The data were obtained with the CORALIE spectrograph at the 1.2 m Swiss telescope in La Silla and the ELODIE spectrograph at the 1.93 m telescope at the Observatoire de Haute Provence. Periodic variations can be observed in the radial velocity time series of individual nights. In the power spectrum of the radial velocity time series there is a clear power excess around 60 muHz, and several individual oscillation frequencies can be distinguished. Our auto-correlation and comb response analysis reveals a large separation of either 4.8 muHz or (its 11.57 muHz alias) 6.7 muHz. We estimate the position of \varepsilon Oph in the HR diagram, and verify whether CESAM shell hydrogen-burning stellar models exist that can reproduce the observed frequency separation.

Theory of the frequency comb output from a femtosecond fiber laser

The output of a femtosecond fiber laser will form a frequency comb that can be phase-locked through feedback to the cavity length and pump power. A perturbative theory is developed to describe this frequency comb output, in particular for a solitonic fiber laser. The effects of resonant dispersion, saturation of the self-amplitude modulation, cavity loss, third-order dispersion, Raman scattering, self-phase modulation, and self-steepening on the spacing and offset of the fiber-laser frequency comb are given. The mechanisms by which the pump power, cavity length and cavity loss control the frequency comb spacing and offset are identified. Transfer functions are derived for the comb response to change in cavity length, pump power or cavity loss. This theory can potentially be applied to other frequency comb sources as well.

Response of Testis and Comb of the Radiothyroidectomized Chick to PMS

THE purpose of this experiment was to learn if pregnant mare serum (PMS) could stimulate gonad and comb growth in the chick in the absence of thyroid hormone. Breneman (1945) and Dorfman et al. (1948) adequately demonstrated that, in the normal chick, PMS caused both testis growth and comb enlargement.Snedecor and Camyre (1966) showed that five-week-old chicks which had been radiothyroidectomized (RTx) at age six days had greatly reduced testis and comb weights. This corroborated the results of Payne (1944) and Morris (1951) with surgically thyroidectomized chicks. Like Morris (1951), Snedecor and Camyre (1966) noted a synergistic effect of thyroid hormone and androgen on the comb in hormone replacement studies in thyroidectomized castrates. Either hormone was able to promote but limited comb growth in the absence of the other. From the results following RTx, however, it was not possible to know whether the reduction of testis size was due .

Actinomycin D and Growth Response of Chick Comb to Androgens

Actinomycin D and Growth Response of Chick Comb to Androgens

Actinomycin D and Growth Response of Chick Comb to Androgens

Actinomycin D and Growth Response of Chick Comb to Androgens

Genetic Changes in the Androgenic Comb Response of Baby Chicks May be Detrimental to Egg Production

THE weight response of the baby chick’s comb to androgenic stimulation from testosterone and gonadotrophin injection has been changed by selection (Jaap, 1962; Nestor, 1964; and Nestor and Jaap, 1965).This report is concerned with the question of whether these genetic changes in hormone response during the first ten days after hatching persist into the pullet laying period. Also, whether changes in the response of cells in the baby chick’s comb are accompanied by changes in the response of other tissues of the bird’s body and whether these responses are age specific or persist throughout life. Should genetic capabilities be established early in life, it would be possible to predict future productive and reproductive performance soon after hatching of the chick.MATERIALS AND METHODSDetails of the origin and maintenance of the populations used in the study were given by Nestor (1964) and Nestor and Jaap (1965). One population designated …

DNA-dependent synthesis of RNA is not implicated in growth response of chick comb to androgens.

Local application of actinomycin D does not detectably modify growth response of the chick comb to androgens. The mode of action of androgens on chick comb (a connective-tissue organ) appears to differ from their action on epithelial-tissue organs such as seminal vesicles and prostate.

Steroid structure and androgencity.

Fifteen derivatives of androstane were compared with testosterone for their androgenic effects on the cockerel comb or the levator ani, seminal vesicle and ventral prostate of immature castrated male rats. The ventral prostate response was a more sensitive end-point for testosterone than the seminal vesicle, while the levator ani response was the least senstive. The cockerel comb response was generally found to parallel that of the rat ventral prostate. In rat bio-assays, testosterone was about 100 times more effective administered parenterally than orally. The presence of a 17β-hydroxyl group was shown to be necessary for maximal androgenic activity regardless of the type of end-point observed. The 17-ketone group was found to be somewhat less active than 17β-hydroxyl in cockerel comb or ventral prostate bio-assays, while the seminal vesicle and levator ani responses were greatly decreased. 5β-Androstanes were invariably much less androgenic than the A4 or 5 a compounds, regardless of the nature of subst...

Assay of subcutaneously administered androgens on the chick's comb.

ABSTRACT The comb response of day old chicks was used to assay androgens administered by subcutaneous injection using both corn oil and aqueous tween vehicles. The use of the oil vehicle afforded a more precise assay method and the comb response was higher than when the aqueous vehicle was employed. When the tween vehicle was used and an arbitrary value of 100 assigned to the activity of testosterone the following relative potencies were found: androst-4-ene-3,17-dione (17), androst-5-ene-3β,17β-diol (49), dehydroepiandrosterone (65), and 19-nortestosterone (35). Using the corn oil vehicle and again setting the activity of testosterone as 100, the following relative potencies were recorded: androst-4-ene-3,17-dione (21), 17β-hydroxyandrostan-3-one (370), and testosterone propionate (395).

Evidence for in Vivo Conversion of C21 Steroids to C19 Androgens in the Bovine

Summary The biosynthetic transformation of progesterone to fecal androgen (androstenedione) in the bovine has been shown. The present study reports the biosynthetic transformation of pregnenolone and 17 α -hydroxyprogesterone to fecal androgen. Following the injection of pregnenolone into the male and female bovine, the chick comb response test demonstrated a significant formation of fecal androgens in the male and a significant increase in fecal androgens in the female. Following the injection of 17 α -hydroxyprogesterone into the female bovine, androgen biosynthesis was evidenced by the excretion of a significant amount of fecal androgens as measured by the chick comb response test. In vitro studies with various mammalian tissues have documented a pathway for androgen biosynthesis involving the following sequence: pregnenolone → progesterone → 17 α -hydroxyprogesterone → androstenedione. The cumulative results of the experiments on bovine androgenesis provide in vivo evidence indicating that androgen biosynthesis in the bovine, as in many other species, occurs via the same pathway. The experimental evidence demonstrates further the major importance of an hepatoenteric pathway for the elimination of the C 19 androgen metabolites of these C 21 hormones.

Gonad and Comb Response of Mature Male Chickens to Diethylstilbestrol as Influenced by Breed and Dosage

DIETHYLSTILBESTROL administered to the immature male chicken brings about an inhibition of the growth of the gonads and comb (Breneman, 1942a; Lorenz, 1945; Thayer et al., 1945; Sykes et al., 1945; and Bird et al., 1947). A comb-testes relationship has been established by Marlow (1948). The removal of combs from chicks at three days of age resulted in a significant increase in testes size.Studies on the gland weights of chicks by Breneman (1941), revealed definite differences between Rhode Island Red and White Leghorn chicks in comb and gonad weights. Comb growth and gonad growth was inhibited in estradiol treated White Leghorn cockerels studied by Breneman (1942b). Hoffmann et al. (1953) measured weights of endocrine glands of twelve-week old chickens representing seven different breeds or strains. They reported statistically significant strain and variety differences for all weights recorded before adjustment for body weight, with only a loss of significance in …

Influence of filtered and no sunlight on weight and comb response in androgen treated cockerels.

ArticleInfluence of Filtered and No Sunlight on Weight and Comb Response in Androgen Treated CockerelsHarry Y. C. Wong, and Edward W. HawthorneHarry Y. C. WongFrom the Department of Physiology, Howard University School of Medicine, Washington, D. C., and Edward W. HawthorneFrom the Department of Physiology, Howard University School of Medicine, Washington, D. C.Published Online:30 Nov 1954https://doi.org/10.1152/ajplegacy.1954.179.3.419MoreSectionsPDF (294 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat "Influence of Filtered and No Sunlight on Weight and Comb Response in Androgen Treated Cockerels." American Journal of Physiology-Legacy Content, 179(3), pp. 419–420 Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByReproduction in the Male, Fertilization, and Early Embryonic DevelopmentREPRODUCTION IN DOMESTIC FOWL More from this issue > Volume 179Issue 3November 1954Pages 419-420 Copyright & PermissionsCopyright © 1954 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1954.179.3.419PubMed13228602History Received 20 July 1954 Published online 30 November 1954 Published in print 30 November 1954 Metrics

Effect of exercise on comb response of androgen-treated capons.

ArticleEffect of Exercise on Comb Response of Androgen-Treated CaponsHarry Y. C. Wong, Nathan Lavenda, and Edward W. HawthorneHarry Y. C. WongFrom the Department of Physiology, College of Medicine, Howard University, Washington, D. C., Nathan LavendaFrom the Department of Physiology, College of Medicine, Howard University, Washington, D. C., and Edward W. HawthorneFrom the Department of Physiology, College of Medicine, Howard University, Washington, D. C.Published Online:01 Aug 1954https://doi.org/10.1152/ajplegacy.1954.178.2.269MoreSectionsPDF (307 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat "Effect of Exercise on Comb Response of Androgen-Treated Capons." American Journal of Physiology-Legacy Content, 178(2), pp. 269–270 Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByDie Kloake als Testorgan für die Wirkung endogener und exogener Geschlechtssteroide beim Huhn (Gallus domesticus)13 May 2010 | Zentralblatt für Veterinärmedizin Reihe A, Vol. 25, No. 1Reproduction in the Male, Fertilization, and Early Embryonic Development More from this issue > Volume 178Issue 2August 1954Pages 269-270 Copyright & PermissionsCopyright © 1954 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1954.178.2.269PubMed13197566History Received 29 March 1954 Published online 1 August 1954 Published in print 1 August 1954 Metrics

The chick comb response to androgen in inbred brown leghorns.

During the senior author’s tenure of a Fulbright Research Scholarship, Doctor Greenwood had available at the Poultry Research Centre several inbred lines of Brown Leghorns (Greenwood and Btyth, 1951; Blyth, 1952). These lines appeared desirable for detecting differences in hormone production and response as well as the relation of the endocrine system to the expression of hybrid vigor in growth rate and egg production. This report is concerned with the variability in response of the baby chick’s comb to testosterone propionate. the androgenic comb response Fussganger (1934) emphasized the small differences in androgenic potency which could be measured by external application of the hormone to the comb of the capon. Ruzicka (1935) was probably the first to suggest that the baby chick comb response be used as an assay for androgens. Since that time there have been many research reports concerned with the possibility of the chick-comb response as a sensitive assay for androgenic potency of unknown solutions....

Response of comb and plumage in thyroidectomized brown Leghorn hens to hormone administration.

Response of comb and plumage in thyroidectomized brown Leghorn hens to hormone administration.

STUDIES ON THE BIOASSAY OF HORMONES—THE ASSAY OF PREGNANT MARE’S SERUM CHORIONIC GONADOTROPHIN

This communication is concerned with studies on the bioassay of pregnant mare’s serum chorionic gonadotrophin using the baby chick. Three endpoints have been studied. The oviduct response was found to be entirely unsuitable and the comb response of the male of doubtful value. However, the testis response appears to be a satisfactory endpoint having the advantages of reasonable sensitivity and reproducibility. materials, animals, methods The pregnant mare’s serum hormone consisted of material kindly supplied by the Upjohn Company and the Schering Corporation. The material was readily soluble in water and was dissolved just before the first injections were done and kept at –5° C. between injections. The total dose per animal was contained in 0.5 cc. of water. The White Leghorn chicks were obtained from the Kerr Chickeries in Frenchtown, N. J., and usually arrived at the laboratory one day after hatching and immediately placed on a diet of starting mash and water.

THE CHICK COMB RESPONSE TO ANDROGENS

Journal Article THE CHICK COMB RESPONSE TO ANDROGENS Get access P. A. DUFF, P. A. DUFF 1From the Departments of Urology, Anatomy, and Biochemistry, College of Physicians and Surgeons, Columbia University NEW YORK CITY Search for other works by this author on: Oxford Academic Google Scholar HUGH H. DARBY HUGH H. DARBY 1From the Departments of Urology, Anatomy, and Biochemistry, College of Physicians and Surgeons, Columbia University NEW YORK CITY Search for other works by this author on: Oxford Academic Google Scholar Endocrinology, Volume 28, Issue 4, 1 April 1941, Pages 643–647, https://doi.org/10.1210/endo-28-4-643 Published: 01 April 1941 Article history Received: 03 October 1940 Published: 01 April 1941