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Sample records for hormone-releasing factor analog

  1. Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat.

    Directory of Open Access Journals (Sweden)

    Alexandra Mangili

    Full Text Available Tesamorelin, a synthetic analog of human growth hormone-releasing factor, decreases visceral adipose tissue (VAT in human immunodeficiency virus (HIV-infected patients with lipodystrophy.1 To evaluate the utility of patient characteristics and validated disease-risk scores, namely indicator variables for the metabolic syndrome defined by the International Diabetes Federation (MetS-IDF or the National Cholesterol Education Program (MetS-NCEP and the Framingham Risk Score (FRS, as predictors of VAT reduction during tesamorelin therapy at 3 and 6 months, and 2 To explore the characteristics of patients who reached a threshold of VAT 1.7 mmol/L, and white race had a significant impact on likelihood of response to tesamorelin after 6 months of therapy (interaction p-values 0.054, 0.063, and 0.025, respectively. No predictive factors were identified at 3 months. The odds of a VAT reduction to <140 cm2 for subjects treated with tesamorelin was 3.9 times greater than that of subjects randomized to placebo after controlling for study, gender, baseline body mass index (BMI and baseline VAT (95% confidence interval [CI] 2.03; 7.44.Individuals with baseline MetS-NCEP, elevated triglyceride levels, or white race were most likely to experience reductions in VAT after 6 months of tesamorelin treatment. The odds of response of VAT <140 cm2 was 3.9 times greater for tesamorelin-treated patients than that of patients receiving placebo.

  2. Growth hormone-releasing factor stimulates proliferation of somatotrophs in vitro

    DEFF Research Database (Denmark)

    Billestrup, Nils; Swanson, L W; Vale, W

    1986-01-01

    The mitogenic effect of the hypothalamic peptides growth hormone-releasing factor (GRF) and somatostatin on cultured growth hormone (GH)-producing cells (somatotrophs) was studied. Using autoradiographic detection of [3H]thymidine uptake and immunocytochemical identification of GH-producing cells...

  3. Goserelin acetate implant: a depot luteinizing hormone-releasing hormone analog for advanced prostate cancer.

    Science.gov (United States)

    Goldspiel, B R; Kohler, D R

    1991-01-01

    Goserelin acetate implant is a newly approved depot formulation of a luteinizing hormone-releasing hormone (LHRH) agonist indicated for palliation of advanced prostate cancer. LHRH superagonists suppress gonadotropin release from the pituitary gland by causing down-regulation of receptors. The sustained-release dosage form contains goserelin acetate dispersed in a biodegradable copolymer matrix and is designed to release active drug over 28 days. Pharmacokinetic studies have demonstrated that, despite nonzero order release of goserelin from the matrix, goserelin acetate implant maintains serum concentrations of testosterone in the range normally found in castrated men (less than 2 nmol/L) throughout the recommended 28-day dosing interval. Response rates similar to those for orchiectomy and estrogen administration have been demonstrated. Combination therapy with either diethylstilbestrol or flutamide has produced favorable results, although the major advantage appears to be a reduction in the tumor flare seen during the first week of LHRH agonist therapy rather than an increase in response rate or survival. Adverse effects are similar to other LHRH agonists and include tumor flare during the first week of therapy, decreased libido, decreased erectile potency, hot flashes, and gynecomastia. In combination with flutamide, additional adverse effects include diarrhea, nausea, vomiting, and elevated hepatic aminotransferases, all of which can be attributed to flutamide administration. Local reactions are minimal; however, some patients require a local anesthetic before goserelin acetate implant injection. The recommended dose is 3.6 mg administered subcutaneously into the upper abdominal wall every 28 days. The average wholesale cost is approximately +320 per month. Formulary addition is recommended.

  4. Active immunization of pigs against growth hormone-releasing factor: effect on concentrations of growth hormone and insulin-like growth factor 1.

    Science.gov (United States)

    Armstrong, J D; Esbenshade, K L; Johnson, J L; Coffey, M T; Heimer, E; Campbell, R M; Mowles, T; Felix, A

    1990-02-01

    Cyclic gilts (96 +/- 1 kg) were used to determine the effect of active immunization against growth hormone-releasing factor GRF(1-29)-NH2 on concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Gilts were immunized against GRF conjugated to human serum albumin (GRF-HSA, n = 5) or HSA alone at 180 d of age (wk 0). Booster doses were administered at wk 9 and 13. Seven days after the second booster (wk 14), blood samples were collected at 15-min intervals for 6 h before feeding and 30, 60, 120, 180 and 240 min after feeding. Eight days after the second booster, all gilts were administered a GRF analog, [desNH2Tyr1,Ala15]-GRF(1-29)-NH2, followed by an opioid agonist, FK33-824. Blood samples were collected at 15-min intervals from -30 to 240 min after injection. Immunization against GRF-HSA resulted in antibody titers, expressed as dilution required to bind 50% of [125I]GRF, ranging from 1:11,000 to 1:60,000 (wk 11 and 14); binding was not detectable or was less than 50% at 1:100 in HSA gilts (P less than .05). Episodic release of GH was abolished by immunization against GRF-HSA (P less than .05). Mean GH was decreased (P less than .07), but basal GH concentrations were not altered (P greater than .15) by immunization against GRF-HSA. Serum concentrations of IGF-1 were similar at wk 0, but concentrations were lower in GRF-HSA than in HSA gilts (P less than .05) at wk 14.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Evolution of the growth hormone-releasing factor (GRF) family of peptides.

    Science.gov (United States)

    Campbell, R M; Scanes, C G

    1992-12-01

    since the discovery of GRF. Examination of the GRF peptide superfamily from an evolutionary perspective has revealed new insights into the synthesis, processing, degradation, conformation and activities of these molecules. Knowledge obtained from these evolutionary comparisons has also become particularly useful in contemporary peptide drug design, which may be liberally viewed as a form of 'artificial evolution' (i.e. the selective pressure being clinical/veterinary requirements for more potent, long-acting GRF analogs).

  6. Effects of active immunization against growth-hormone releasing factor on puberty and reproductive development in gilts.

    Science.gov (United States)

    Swanchara, K W; Armstrong, J D; Britt, J H

    1999-07-01

    Hormones within the somatotropin cascade influence several physiological traits, including growth and reproduction. Active immunization against growth hormone-releasing factor (GRFi) initiated at 3 or 6 mo of age decreased weight gain, increased deposition of fat, and delayed puberty in heifers. Two experiments were conducted to investigate the effects of GRFi on puberty and subsequent ovulation rate in gilts. Crossbred gilts were actively immunized against GRF-(1-29)-(Gly)2-Cys-NH2 conjugated to human serum albumin (GRFi) or against human serum albumin alone (HSAi). In Exp. 1, gilts were immunized against GRF (n = 12) or HSA (n = 12) at 92 +/- 1 d of age. At 191 d of age, antibody titers against GRF were greater (P gilts. The GRFi decreased (P gilts were immunized against GRF (n = 35) or HSA (n = 35) at 35 +/- 1 d of age. The GRFi at 35 d of age did not alter the number of surface follicles or uterine weight between 93 and 102 d of age, but GRFi decreased (P Immunization against GRF reduced (P gilts, but ovulation rate was lower (P gilts. Thus, GRFi at 92 or 35 d of age decreased serum ST, IGF-I, and BW in prepubertal gilts without altering age of puberty. However, GRFi at 35 d of age, but not 92 d of age, decreased ovulation rate. These results indicate that alterations in the somatotropic axis at 1 mo of age can influence reproductive development in pubertal gilts.

  7. Adenohypophysial changes in mice transgenic for human growth hormone-releasing factor

    DEFF Research Database (Denmark)

    Stefaneanu, L; Kovacs, K; Horvath, E

    1989-01-01

    The effect of protracted GH-releasing factor (GRF) stimulation on adenohypophysial morphology was investigated in six mice transgenic for human GRF (hGRF). All animals had significantly higher plasma levels of GH and GRF and greater body weights than controls. Eight-month-old mice were killed...

  8. FGF growth factor analogs

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY; Takahashi, Kazuyuki [Germantown, MD

    2012-07-24

    The present invention provides a fibroblast growth factor heparin-binding analog of the formula: ##STR00001## where R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, X, Y and Z are as defined, pharmaceutical compositions, coating compositions and medical devices including the fibroblast growth factor heparin-binding analog of the foregoing formula, and methods and uses thereof.

  9. Synthesis and structure-activity studies on novel analogs of human growth hormone releasing hormone (GHRH) with enhanced inhibitory activities on tumor growth.

    Science.gov (United States)

    Zarandi, Marta; Cai, Renzhi; Kovacs, Magdolna; Popovics, Petra; Szalontay, Luca; Cui, Tengjiao; Sha, Wei; Jaszberenyi, Miklos; Varga, Jozsef; Zhang, XianYang; Block, Norman L; Rick, Ferenc G; Halmos, Gabor; Schally, Andrew V

    2017-03-01

    The syntheses and biological evaluations of new GHRH analogs of Miami (MIA) series with greatly increased anticancer activity are described. In the design and synthesis of these analogs, the following previous substitutions were conserved: D-Arg2, Har9, Abu15, and Nle27. Most new analogs had Ala at position 8. Since replacements of both Lys12 and Lys21 with Orn increased resistance against enzymatic degradation, these modifications were kept. The substitutions of Arg at both positions 11 and 20 by His were also conserved. We kept D-Arg28, Har29 -NH2 at the C-terminus or inserted Agm or 12-amino dodecanoic acid amide at position 30. We incorporated pentafluoro-Phe (Fpa5), instead of Cpa, at position 6 and Tyr(Me) at position 10 and ω-amino acids at N-terminus of some analogs. These GHRH analogs were prepared by solid-phase methodology and purified by HPLC. The evaluation of the activity of the analogs on GH release was carried out in vitro on rat pituitaries and in vivo in male rats. Receptor binding affinities were measured in vitro by the competitive binding analysis. The inhibitory activity of the analogs on tumor proliferation in vitro was tested in several human cancer cell lines such as HEC-1A endometrial adenocarcinoma, HCT-15 colorectal adenocarcinoma, and LNCaP prostatic carcinoma. For in vivo tests, various cell lines including PC-3 prostate cancer, HEC-1A endometrial adenocarcinoma, HT diffuse mixed β cell lymphoma, and ACHN renal cell carcinoma cell lines were xenografted into nude mice and treated subcutaneously with GHRH antagonists at doses of 1-5μg/day. Analogs MIA-602, MIA-604, MIA-610, and MIA-640 showed the highest binding affinities, 30, 58, 48, and 73 times higher respectively, than GHRH (1-29) NH2. Treatment of LNCaP and HCT-15 cells with 5μM MIA-602 or MIA-690 decreased proliferation by 40%-80%. In accord with previous tests in various human cancer lines, analog MIA-602 showed high inhibitory activity in vivo on growth of PC-3 prostate

  10. Growth hormone-releasing peptide-biotin conjugate stimulates myocytes differentiation through insulin-like growth factor-1 and collagen type I.

    Science.gov (United States)

    Lim, Chae Jin; Jeon, Jung Eun; Jeong, Se Kyoo; Yoon, Seok Jeong; Kwon, Seon Deok; Lim, Jina; Park, Keedon; Kim, Dae Yong; Ahn, Jeong Keun; Kim, Bong-Woo

    2015-09-01

    Based on the potential beneficial effects of growth hormone releasing peptide (GHRP)-6 on muscle functions, a newly synthesized GHRP-6-biotin conjugate was tested on cultured myoblast cells. Increased expression of myogenic marker proteins was observed in GHRP-6-biotin conjugate-treated cells. Additionally, increased expression levels of insulin-like growth factor-1 and collagen type I were observed. Furthermore, GHRP-6-biotin conjugate-treated cells showed increased metabolic activity, as indicated by increased concentrations of energy metabolites, such as ATP and lactate, and increased enzymatic activity of lactate dehydrogenase and creatine kinase. Finally, binding protein analysis suggested few candidate proteins, including desmin, actin, and zinc finger protein 691 as potential targets for GHRP6-biotin conjugate action. These results suggest that the newly synthesized GHRP-6-biotin conjugate has myogenic stimulating activity through, at least in part, by stimulating collagen type I synthesis and several key proteins. Practical applications of the GHRP-6-biotin conjugate could include improving muscle condition.

  11. Relative potencies of the somatostatin analogs octreotide, BIM-23014, and RC-160 on the inhibition of hormone release by cultured human endocrine tumor cells and normal rat anterior pituitary cells

    NARCIS (Netherlands)

    L.J. Hofland (Leo); P.M. van Koetsveld (Peter); M. Waaijers (Marlijn); J. Zuyderwijk; S.W.J. Lamberts (Steven)

    1994-01-01

    textabstractIn the present study we investigated the effects of the somatostatin (SS) analogs octreotide, RC-160, and BIM-23014 on GH release by cultured cells of human GH-secreting pituitary tumors, in normal rat anterior pituitary cells, and on gastrin release by

  12. Massive weight loss restores 24-hour growth hormone release profiles and serum insulin-like growth factor-I levels in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, M H; Hvidberg, A; Juul, A

    1995-01-01

    In the present study, we 1) determined whether the impaired spontaneous 24-h GH secretion as well as the blunted GH response to provocative testing in obese subjects are persistent disorders or transient defects reversed with weight loss and 2) investigated 24-h urinary GH excretion and basal...... levels of insulin-like growth factor-I (IGF-I), IGF-binding protein-3 (IGFBP-3), as well as insulin in obese subjects before and after a massive weight loss. We studied 18 obese subjects (age, 26 +/- 1 yr; body mass index, 40.9 +/- 1.1 kg/m2); 18 normal age-, and sex-matched control subjects; and 9...... reversible defects in 24-h spontaneous GH release profiles, basal IGF-I levels, and the IGF-I/IGFBP-3 molar ratio in obese subjects. The recovery of the 24-h GH release points to an acquired transient defect rather than a persistent preexisting disorder....

  13. Massive weight loss restores 24-hour growth hormone release profiles and serum insulin-like growth factor-I levels in obese subjects

    DEFF Research Database (Denmark)

    Rasmussen, M H; Hvidberg, A; Juul, A

    1995-01-01

    In the present study, we 1) determined whether the impaired spontaneous 24-h GH secretion as well as the blunted GH response to provocative testing in obese subjects are persistent disorders or transient defects reversed with weight loss and 2) investigated 24-h urinary GH excretion and basal...... levels of insulin-like growth factor-I (IGF-I), IGF-binding protein-3 (IGFBP-3), as well as insulin in obese subjects before and after a massive weight loss. We studied 18 obese subjects (age, 26 +/- 1 yr; body mass index, 40.9 +/- 1.1 kg/m2); 18 normal age-, and sex-matched control subjects; and 9...... reduced weight obese subjects after a diet-induced average weight loss of 30.3 +/- 4.6 kg. Twenty-four-hour spontaneous GH secretion was estimated by obtaining 3240 integrated 20-min blood samples using a constant blood withdrawal technique and computerized algorithms. Body composition was determined...

  14. Nutrient Sensing Overrides Somatostatin and Growth Hormone-Releasing Hormone to Control Pulsatile Growth Hormone Release.

    Science.gov (United States)

    Steyn, F J

    2015-07-01

    Pharmacological studies reveal that interactions between hypothalamic inhibitory somatostatin and stimulatory growth hormone-releasing hormone (GHRH) govern pulsatile GH release. However, in vivo analysis of somatostatin and GHRH release into the pituitary portal vasculature and peripheral GH output demonstrates that the withdrawal of somatostatin or the appearance of GHRH into pituitary portal blood does not reliably dictate GH release. Consequently, additional intermediates acting at the level of the hypothalamus and within the anterior pituitary gland are likely to contribute to the release of GH, entraining GH secretory patterns to meet physiological demand. The identification and validation of the actions of such intermediates is particularly important, given that the pattern of GH release defines several of the physiological actions of GH. This review highlights the actions of neuropeptide Y in regulating GH release. It is acknowledged that pulsatile GH release may not occur selectively in response to hypothalamic control of pituitary function. As such, interactions between somatotroph networks, the median eminence and pituitary microvasculature and blood flow, and the emerging role of tanycytes and pericytes as critical regulators of pulsatility are considered. It is argued that collective interactions between the hypothalamus, the median eminence and pituitary vasculature, and structural components within the pituitary gland dictate somatotroph function and thereby pulsatile GH release. These interactions may override hypothalamic somatostatin and GHRH-mediated GH release, and modify pulsatile GH release relative to the peripheral glucose supply, and thereby physiological demand. © 2015 British Society for Neuroendocrinology.

  15. Effects of chronic and subtoxic chlorobenzenes on adrenocorticotrophic hormone release.

    Science.gov (United States)

    Molnár, Zsolt; Pálföldi, Regina; László, Anna; Radács, Marianna; Sepp, Krisztián; Hausinger, Péter; Tiszlavicz, László; Valkusz, Zsuzsanna; Gálfi, Márta

    2015-08-01

    Many environmental chemicals and pesticides have been found to alter neuroendocrine communication in exposed biological objects. The environmental loads have primary and secondary effects that can alter the homeostatic regulation potential. Since it is difficult to avoid human exposition, a potentially important area of research to develop in vivo and in vitro experimental models. In this context, the primary aim of this study was to demonstrate the effects of chlorobenzenes on adrenocorticotrophic hormone (ACTH) release. In our experimental study, male Wistar rats were exposed to 0.1, 1.0 and 10 μg/b.w. (body weight)kg of 1,2,4- trichlorobenzene and hexachlorobenzene (ClB) mix via gastric tube for 30, 60 or 90 days. At the endpoints of the experiment blood samples were taken and animals were decapitated. Primary, monolayer adenohypophysis cell cultures were prepared by enzymatic and mechanical digestion. The ACTH hormone content in serum and supernatant media was measured by immuno-chemiluminescence assay. The Mg(2+)-dependent ATPase activity was determined by modified method of Martin and Dotty. Significant differences were detected in the hormone release between the control and treated groups. The hormone release was enhanced characteristically in exposed groups depending upon the dose and duration of exposure. The Mg(2+)-ATPase activity enhanced after chronic and subtoxic ClB exposition. Light microscopy revealed that the adenohypophysis seemed to be more abundant. Results indicate that Wistar rats exposed to subtoxic ClB have direct and indirect effects on hypothalamus-hypophysis-adrenal axis. Copyright © 2015. Published by Elsevier B.V.

  16. Dual chain synthetic heparin-binding growth factor analogs

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY

    2012-04-24

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  17. Dual chain synthetic heparin-binding growth factor analogs

    Science.gov (United States)

    Zamora, Paul O [Gaithersburg, MD; Pena, Louis A [Poquott, NY; Lin, Xinhua [Plainview, NY

    2009-10-06

    The invention provides synthetic heparin-binding growth factor analogs having two peptide chains each branched from a branch moiety, such as trifunctional amino acid residues, the branch moieties separated by a first linker of from 3 to about 20 backbone atoms, which peptide chains bind a heparin-binding growth factor receptor and are covalently bound to a non-signaling peptide that includes a heparin-binding domain, preferably by a second linker, which may be a hydrophobic second linker. The synthetic heparin-binding growth factor analogs are useful as pharmaceutical agents, soluble biologics or as surface coatings for medical devices.

  18. Substantial expression of luteinizing hormone-releasing hormone (LHRH) receptor type I in human uveal melanoma

    Science.gov (United States)

    Schally, Andrew V.; Block, Norman L; Dezso, Balazs; Olah, Gabor; Rozsa, Bernadett; Fodor, Klara; Buglyo, Armin; Gardi, Janos; Berta, Andras; Halmos, Gabor

    2013-01-01

    Uveal melanoma is the most common primary intraocular malignancy in adults, with a very high mortality rate due to frequent liver metastases. Consequently, the therapy of uveal melanoma remains a major clinical challenge and new treatment approaches are needed. For improving diagnosis and designing a rational and effective therapy, it is essential to elucidate molecular characteristics of this malignancy. The aim of this study therefore was to evaluate as a potential therapeutic target the expression of luteinizing hormone-releasing hormone (LHRH) receptor in human uveal melanoma. The expression of LHRH ligand and LHRH receptor transcript forms was studied in 39 human uveal melanoma specimens by RT-PCR using gene specific primers. The binding charachteristics of receptors for LHRH on 10 samples were determined by ligand competition assays. The presence of LHRH receptor protein was further evaluated by immunohistochemistry. The expression of mRNA for type I LHRH receptor was detected in 18 of 39 (46%) of tissue specimens. mRNA for LHRH-I ligand could be detected in 27 of 39 (69%) of the samples. Seven of 10 samples investigated showed high affinity LHRH-I receptors. The specific presence of full length LHRH receptor protein was further confirmed by immunohistochemistry. A high percentage of uveal melanomas express mRNA and protein for type-I LHRH receptors. Our results support the merit of further investigation of LHRH receptors in human ophthalmological tumors. Since diverse analogs of LHRH are in clinical trials or are already used for the treatment of various cancers, these analogs could be considered for the LHRH receptor-based treatment of uveal melanoma. PMID:24077773

  19. Optomechanical Analogy for Toy Cosmology with Quantized Scale Factor

    Directory of Open Access Journals (Sweden)

    Joseph A. Smiga

    2017-09-01

    Full Text Available The simplest cosmology—the Friedmann–Robertson–Walker–Lemaître (FRW model— describes a spatially homogeneous and isotropic universe where the scale factor is the only dynamical parameter. Here we consider how quantized electromagnetic fields become entangled with the scale factor in a toy version of the FRW model. A system consisting of a photon, source, and detector is described in such a universe, and we find that the detection of a redshifted photon by the detector system constrains possible scale factor superpositions. Thus, measuring the redshift of the photon is equivalent to a weak measurement of the underlying cosmology. We also consider a potential optomechanical analogy system that would enable experimental exploration of these concepts. The analogy focuses on the effects of photon redshift measurement as a quantum back-action on metric variables, where the position of a movable mirror plays the role of the scale factor. By working in the rotating frame, an effective Hubble equation can be simulated with a simple free moving mirror.

  20. Tumor growth inhibition in patients with prostatic carcinoma treated with luteinizing hormone-releasing hormone agonists.

    Science.gov (United States)

    Tolis, G; Ackman, D; Stellos, A; Mehta, A; Labrie, F; Fazekas, A T; Comaru-Schally, A M; Schally, A V

    1982-01-01

    Ten patients with prostatic carcinoma--six with stage C and four with stage D disease--were treated for 6 weeks to 12 months with agonistic analogues of luteinizing hormone-releasing hormone (LH-RH). [D-Trp6]LH-RH was given subcutaneously once daily at a dose of 100 microgram and [D-Ser(But)6]des-GlyNH2(10)-LH-RH ethylamide (HOE 766) was given subcutaneously (50 microgram once daily) or intranasally (500 microgram twice daily). In all patients, mean plasma testosterone levels showed a 75% suppression by the third week of treatment and remained low thereafter. This was followed by a decrease or normalization of plasma acid phosphatase levels by the second month of treatment and a 47% decrease in serum alkaline phosphatase by the 10th week of treatment in all but one patient. In patients with stage C disease presenting with prostatism or urinary outflow obstruction, there was a noticeable clinical improvement. In two such patients, a decrease in the size of the prostate was confirmed by ultrasonography. In patients with stage D disease manifested by diffuse bone metastases, there was relief of bone pain, and in one patient treated for greater than 12 months the improvement was documented by radioisotope bone imaging. It is concluded that superactive agonistic LH-RH analogues hold promise as therapeutic agents in patients with androgen-sensitive prostatic adenocarcinoma. Furthermore, the analogous of LH-RH may be used to assess the responsiveness of patients to surgical castration. Long-term administration of LH-RH analogues could become an alternative to surgical castration and estrogen therapy for the treatment of hormone-dependent prostatic carcinoma. Images PMID:6461861

  1. Antagonists of Growth Hormone-Releasing Hormone Inhibit the Growth of U-87MG Human Glioblastoma in Nude Mice

    Directory of Open Access Journals (Sweden)

    Hippokratis Kiaris

    2000-05-01

    Full Text Available Antagonists of growth hormone-releasing hormone(GH-RH inhibit the growth of various cancers by mechanisms that involve the suppression of the insulin-like growth factor (IGF -I and/or IGF-II. In view of the importance of the IGF system in glioma tumorigenesis, the effects of GH-RH antagonists MZ-5-156 and JV-1-36 were investigated in nude mice bearing subcutaneous and orthotopic xenografts of U-87MG human glioblastomas. After 4 weeks of therapy with MZ-5-156 or JV-1-36 at the dose of 20 µmg/day per animal, the final volume of subcutaneous U-87MG tumors was significantly (P < .01 decreased by 84% and 76%, respectively, as compared with controls. Treatment with GHRH antagonists also reduced tumor weight and the levels of mRNA for IGF receptor type I (IGFR-I. A reduction in the mRNA levels for IGF-II was found in tumors of mice treated with MZ-5-156. Treatment with MZ-5-156 or JV-1-36 also extended the survival of nude mice implanted orthotopically with U-87MG glioblastomas by 81% (P < .005 and 18%, respectively, as compared with the controls. Exposure in vitro to GH-RH antagonists MZ-5-156 or JV-1-36 at 1 MM concentration for 24 hours decreased the tumorigenicity of U-87MG cells in nude mice by 10% to 30% and extended the latency period for the development of subcutaneous palpable tumors by 31% to 56%, as compared with the controls. Exposure of U-87MG cells to GH-RH antagonists in vitro also resulted in a time-dependent increase in the mRNA levels of IGFR-II or a decrease in the mRNA levels of IGFR-I. mRNA for GH-RH was detected in U87MG cells and xenografts implying that GH-RH may play a role in the pathogenesis of this tumor. Our results suggest that GH-RH antagonists MZ-5-156 and JV-136 inhibit the growth of U-87MG human glioblastoma by mechanisms that involve the suppression of IGF system. Antagonistic analogs of GH-RH merit further development for the treatment of malignant glioblastoma.

  2. Growth hormone-releasing peptide ghrelin inhibits homocysteine-induced endothelial dysfunction in porcine coronary arteries and human endothelial cells.

    Science.gov (United States)

    Hedayati, Nasim; Annambhotla, Suman; Jiang, Jun; Wang, Xinwen; Chai, Hong; Lin, Peter H; Yao, Qizhi; Chen, Changyi

    2009-01-01

    Ghrelin, a novel growth hormone-releasing peptide, is implicated to play a protective role in cardiovascular tissues. However, it is not clear whether ghrelin protects vascular tissues from injury secondary to risk factors such as homocysteine (Hcy). This study investigated the effect and potential mechanisms of ghrelin on Hcy-induced endothelial dysfunction. Porcine coronary artery rings were incubated for 24 hours with ghrelin (100 ng/mL), Hcy (50 microM), or ghrelin plus Hcy. Endothelial vasomotor function was evaluated using the myograph tension model. The response to the thromboxane A(2)analog U46619, bradykinin, and sodium nitroprusside was analyzed. Endothelial nitric oxide synthase (eNOS) expression was determined using real-time polymerase chain reaction and immunohistochemistry staining, and superoxide anion production was documented lucigenin-enhanced chemiluminescence analysis. Human coronary artery endothelial cells (HCAECs) were treated with different concentrations of Hcy, ghrelin, or antighrelin receptor antibody for 24 hours, and eNOS protein levels were determined by Western blot analysis. Maximal contraction with U46619 and endothelium-independent vasorelaxation with sodium nitroprusside were not different among the four groups. However, endothelium-dependent vasorelaxation with bradykinin (10(-6) M) was significantly reduced by 34% with Hcy compared with controls (P ghrelin to Hcy had a protective effect, with 61.6% relaxation, which was similar to controls (64.7%). Homocysteine significantly reduced eNOS expression, whereas ghrelin cotreatment effectively restored eNOS expression to the control levels. Superoxide anion levels, which were increased by 100% with Hcy, returned to control levels with ghrelin cotreatment. Ghrelin also effectively blocked the Hcy-induced decrease of eNOS protein levels in HCAECs in a concentration-dependent manner. Antighrelin receptor antibody effectively inhibited the effect of ghrelin. Ghrelin has a protective

  3. Growth hormone-releasing hormone attenuates cardiac hypertrophy and improves heart function in pressure overload-induced heart failure.

    Science.gov (United States)

    Gesmundo, Iacopo; Miragoli, Michele; Carullo, Pierluigi; Trovato, Letizia; Larcher, Veronica; Di Pasquale, Elisa; Brancaccio, Mara; Mazzola, Marta; Villanova, Tania; Sorge, Matteo; Taliano, Marina; Gallo, Maria Pia; Alloatti, Giuseppe; Penna, Claudia; Hare, Joshua M; Ghigo, Ezio; Schally, Andrew V; Condorelli, Gianluigi; Granata, Riccarda

    2017-11-07

    It has been shown that growth hormone-releasing hormone (GHRH) reduces cardiomyocyte (CM) apoptosis, prevents ischemia/reperfusion injury, and improves cardiac function in ischemic rat hearts. However, it is still not known whether GHRH would be beneficial for life-threatening pathological conditions, like cardiac hypertrophy and heart failure (HF). Thus, we tested the myocardial therapeutic potential of GHRH stimulation in vitro and in vivo, using GHRH or its agonistic analog MR-409. We show that in vitro, GHRH(1-44)NH 2 attenuates phenylephrine-induced hypertrophy in H9c2 cardiac cells, adult rat ventricular myocytes, and human induced pluripotent stem cell-derived CMs, decreasing expression of hypertrophic genes and regulating hypertrophic pathways. Underlying mechanisms included blockade of Gq signaling and its downstream components phospholipase Cβ, protein kinase Cε, calcineurin, and phospholamban. The receptor-dependent effects of GHRH also involved activation of Gα s and cAMP/PKA, and inhibition of increase in exchange protein directly activated by cAMP1 (Epac1). In vivo, MR-409 mitigated cardiac hypertrophy in mice subjected to transverse aortic constriction and improved cardiac function. Moreover, CMs isolated from transverse aortic constriction mice treated with MR-409 showed improved contractility and reversal of sarcolemmal structure. Overall, these results identify GHRH as an antihypertrophic regulator, underlying its therapeutic potential for HF, and suggest possible beneficial use of its analogs for treatment of pathological cardiac hypertrophy. Copyright © 2017 the Author(s). Published by PNAS.

  4. Protection of germinal epithelium with luteinizing hormone-releasing hormone analogue

    Energy Technology Data Exchange (ETDEWEB)

    Nseyo, U.O.; Huben, R.P.; Klioze, S.S.; Pontes, J.E.

    1985-07-01

    A dog model for chemotherapy and radiation-induced testicular damage was created to study the protective potential of superactive analogue of luteinizing hormone-releasing hormone, buserelin. Buserelin appeared to offer protection of the canine germinal epithelium against cyclophosphamide, cisplatinum and radiation. Clinical trials with buserelin in patients of reproductive age undergoing treatment for cancer should be encouraged.

  5. Pituitary mammosomatotroph adenomas develop in old mice transgenic for growth hormone-releasing hormone

    DEFF Research Database (Denmark)

    Asa, S L; Kovacs, K; Stefaneanu, L

    1990-01-01

    It has been shown that mice transgenic for human growth hormone-releasing hormone (GRH) develop hyperplasia of pituitary somatotrophs and mammosomatotrophs, cells capable of producing both growth hormone and prolactin, by 8 months of age. We now report for the first time that old GRH...

  6. Body fat affects mouse reproduction, ovarian hormone release, and response to follicular stimulating hormone.

    Science.gov (United States)

    Sirotkin, Alexander V; Fabian, Dušan; Babeľová Kubandová, Janka; Vlčková, Radoslava; Alwasel, Saleh; Harrath, Abdel Halim

    2017-12-07

    We investigated the effects of body fat content on mouse fecundity, ovarian hormone release, and their response to follicle stimulation hormone (FSH). 4 types of females were produced: lean (group 1), normal (group 2), slightly fat (group 3), and significantly fat (group 4). The body weights, fat content, fertility rate, embryo number produced, retarded and degenerated embryo percentage, the release of progesterone (P4), testosterone (T), and insulin-like growth factor I (IGF-I) by isolated ovaries cultured with and without FSH (1.0IU/mL medium) were evaluated. A gradual increase in body weight and fat contents from groups 1 to 4 was observed. Group 2 had higher fertility rate than those from the other groups. Groups 2 and 3 had fewer retarded and degenerated embryos that those from groups 1 and 4. Embryo production rate was not different among the groups. P4 and T secretion was higher from group 4 than in those from groups 1-3; secretion of IGF-I of group 3 was less than that of groups 1, 2, and 4. FSH promoted ovarian T output in all groups and stimulated ovarian P4 release in groups 1, 3, and 4, but not in group 2. FSH did not affect IGF-I release in any group. Therefore, both malnutrition and overfeeding can affect body weight and fat content in female mice, reducing embryo quality or developmental capacity, but not fertility and embryo production. Excess weight or fat can have stimulatory effects on ovarian P4 and T, but inhibitory effects on ovarian IGF-I release. Both leanness and excess weight or fat can induce the stimulatory action of FSH on ovarian P4. Copyright © 2017 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  7. Growth hormone response to growth hormone-releasing peptide-2 in growth hormone-deficient Little mice

    Science.gov (United States)

    Peroni, Cibele N.; Hayashida, Cesar Y.; Nascimento, Nancy; Longuini, Viviane C.; Toledo, Rodrigo A.; Bartolini, Paolo; Bowers, Cyril Y.; Toledo, Sergio P.A.

    2012-01-01

    OBJECTIVE: To investigate a possible direct, growth hormone-releasing, hormone-independent action of a growth hormone secretagogue, GHRP-2, in pituitary somatotroph cells in the presence of inactive growth hormone-releasing hormone receptors. MATERIALS AND METHODS: The responses of serum growth hormone to acutely injected growth hormone-releasing P-2 in lit/lit mice, which represent a model of GH deficiency arising from mutated growth hormone-releasing hormone-receptors, were compared to those observed in the heterozygous (lit/+) littermates and wild-type (+/+) C57BL/6J mice. RESULTS: After the administration of 10 mcg of growth hormone-releasing P-2 to lit/lit mice, a growth hormone release of 9.3±1.5 ng/ml was observed compared with 1.04±1.15 ng/ml in controls (pgrowth hormone release of 34.5±9.7 ng/ml and a higher growth hormone release of 163±46 ng/ml were induced in the lit/+ mice and wild-type mice, respectively. Thus, GHRP-2 stimulated growth hormone in the lit/lit mice, and the release of growth hormone in vivo may be only partially dependent on growth hormone-releasing hormone. Additionally, the plasma leptin and ghrelin levels were evaluated in the lit/lit mice under basal and stimulated conditions. CONCLUSIONS: Here, we have demonstrated that lit/lit mice, which harbor a germline mutation in the Growth hormone-releasing hormone gene, maintain a limited but statistically significant growth hormone elevation after exogenous stimulation with GHRP-2. The present data probably reflect a direct, growth hormone-independent effect on Growth hormone S (ghrelin) stimulation in the remaining pituitary somatotrophs of little mice that is mediated by growth hormone S-R 1a. PMID:22473409

  8. Growth hormone releasing hormone or growth hormone treatment in growth hormone insufficiency?

    OpenAIRE

    Smith, P J; Brook, C G

    1988-01-01

    Sixteen prepubertal children who were insufficient for growth hormone were treated with growth hormone releasing hormone (GHRH) 1-40 and GHRH 1-29 for a mean time of nine months (range 6-12 months) with each peptide. Eleven children received GHRH 1-40 in four subcutaneous nocturnal pulses (dose 4-8 micrograms/kg/day) and eight (three of whom were also treated with GHRH 1-40) received GHRH 1-29 twice daily (dose 8-16 micrograms/kg/day). Altogether 73% of the children receiving GHRH 1-40 and 63...

  9. Derivation of Diverse Hormone-Releasing Pituitary Cells from Human Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Bastian Zimmer

    2016-06-01

    Full Text Available Human pluripotent stem cells (hPSCs provide an unlimited cell source for regenerative medicine. Hormone-producing cells are particularly suitable for cell therapy, and hypopituitarism, a defect in pituitary gland function, represents a promising therapeutic target. Previous studies have derived pituitary lineages from mouse and human ESCs using 3D organoid cultures that mimic the complex events underlying pituitary gland development in vivo. Instead of relying on unknown cellular signals, we present a simple and efficient strategy to derive human pituitary lineages from hPSCs using monolayer culture conditions suitable for cell manufacturing. We demonstrate that purified placode cells can be directed into pituitary fates using defined signals. hPSC-derived pituitary cells show basal and stimulus-induced hormone release in vitro and engraftment and hormone release in vivo after transplantation into a murine model of hypopituitarism. This work lays the foundation for future cell therapy applications in patients with hypopituitarism.

  10. Suppression of androgen production by D-tryptophan-6-luteinizing hormone-releasing hormone in man.

    Science.gov (United States)

    Tolis, G; Mehta, A; Comaru-Schally, A M; Schally, A V

    1981-01-01

    Four male transsexual subjects were given a superactive luteinizing hormone-releasing hormone (LHRH) analogue, D-tryptophan-6-LHRH at daily doses of 100 micrograms for 3--6 mo. A decrease in beard growth, acne, and erectile potency was noted; the latter was documented objectively with the recordings of nocturnal penile tumescence episodes. Plasma testosterone and dihydrotestosterone levels fell to castrate values; basal prolactin and luteinizing hormone levels showed a small decline, whereas the acutely releasable luteinizing hormone was significantly suppressed. A rise of plasma testosterone from castrate to normal levels was demonstrable with the use of human chorionic gonadotropin. Discontinuation of treatment led to a normalization of erectile potency and plasma testosterone. The suppression of Leydig cell function by D-tryptophan-6-LHRH might have wide application in reproductive biology and in endocrine-dependent neoplasia (where it could replace surgical castration). PMID:6456277

  11. Growth hormone-releasing hormone-producing pancreatic neuroendocrine tumor in a multiple endocrine neoplasia type 1 family with an uncommon phenotype.

    Science.gov (United States)

    Sala, Elisa; Ferrante, Emanuele; Verrua, Elisa; Malchiodi, Elena; Mantovani, Giovanna; Filopanti, Marcello; Ferrero, Stefano; Pietrabissa, Andrea; Vanoli, Alessandro; La Rosa, Stefano; Zatelli, Maria C; Beck-Peccoz, Paolo; Verga, Uberta

    2013-07-01

    The objective of this study was to describe a multiple endocrine neoplasia type 1 (MEN1) family characterized by primary hyperparathyroidism, in association with acromegaly because of ectopic growth hormone-releasing hormone (GHRH) secretion by a pancreatic neuroendocrine tumor in a young man and with a bronchial carcinoid in his mother. We investigate the clinical, radiological imaging, histopathologic findings, and therapy. An 18-year-old man successfully underwent subtotal parathyroidectomy for primary hyperparathyroidism. A subsequent genetic analysis showed a MEN1 gene mutation. Three years later, acromegaly because of ectopic GHRH secretion was diagnosed (pituitary MRI negative and elevated GHRH levels). A search for an ectopic tumor was unsuccessful and somatostatin analog therapy was started. Successively, scintigraphy with somatostatin analogs (68-Ga-DOTATOC-PET) showed three focal areas in the pancreatic tail. Distal pancreatectomy showed multiple pancreatic neuroendocrine tumors and hormonal status was normalized. Afterwards, the evaluation of the patient's mother, carrying the same mutation, indicated a primary hyperparathyroidism and a 4 cm lung mass. The patient underwent subtotal pneumonectomy and the histological analysis was consistent with the diagnosis of a typical bronchial carcinoid. In conclusion, an atypical phenotype may be recorded in MEN1 families, thus emphasizing the importance of the new imaging and surgical techniques in the diagnosis and treatment of such a rare disease.

  12. Luteinizing Hormone-Releasing Hormone Agonists are Superior to Subcapsular Orchiectomy in Lowering Testosterone Levels of Men with Prostate Cancer

    DEFF Research Database (Denmark)

    Østergren, Peter Busch; Kistorp, Caroline; Fode, Mikkel

    2017-01-01

    levels between patients undergoing subcapsular orchiectomy and patients treated with the luteinizing hormone-releasing hormone agonist triptorelin. MATERIALS AND METHODS: In this randomized clinical trial we included 58 consecutive hormone naïve men diagnosed with advanced prostate cancer at Herlev...

  13. Antiproliferative effect of growth hormone-releasing hormone (GHRH antagonist on ovarian cancer cells through the EGFR-Akt pathway

    Directory of Open Access Journals (Sweden)

    Varga Jozsef

    2010-05-01

    Full Text Available Abstract Background Antagonists of growth hormone-releasing hormone (GHRH are being developed for the treatment of various human cancers. Methods MTT assay was used to test the proliferation of SKOV3 and CaOV3. The splice variant expression of GHRH receptors was examined by RT-PCR. The expression of protein in signal pathway was examined by Western blotting. siRNA was used to block the effect of EGFR. Results In this study, we investigated the effects of a new GHRH antagonist JMR-132, in ovarian cancer cell lines SKOV3 and CaOV3 expressing splice variant (SV1 of GHRH receptors. MTT assay showed that JMR-132 had strong antiproliferative effects on SKOV3 and CaOV3 cells in both a time-dependent and dose-dependent fashion. JMR-132 also induced the activation and increased cleaved caspase3 in a time- and dose-dependent manner in both cell lines. In addition, JMR-132 treatments decreased significantly the epidermal growth factor receptor (EGFR level and the phosphorylation of Akt (p-Akt, suggesting that JMR-132 inhibits the EGFR-Akt pathway in ovarian cancer cells. More importantly, treatment of SKOV3 and CaOV3 cells with 100 nM JMR-132 attenuated proliferation and the antiapoptotic effect induced by EGF in both cell lines. After the knockdown of the expression of EGFR by siRNA, the antiproliferative effect of JMR-132 was abolished in SKOV3 and CaOV3 cells. Conclusions The present study demonstrates that the inhibitory effect of the GHRH antagonist JMR-132 on proliferation is due, in part, to an interference with the EGFR-Akt pathway in ovarian cancer cells.

  14. Biosynthesis and the conjugation of magnetite nanoparticles with luteinizing hormone releasing hormone (LHRH).

    Science.gov (United States)

    Obayemi, J D; Dozie-Nwachukwu, S; Danyuo, Y; Odusanya, O S; Anuku, N; Malatesta, K; Soboyejo, W O

    2015-01-01

    This paper presents the results of an experimental study of the biosynthesis of magnetite nanoparticles (BMNPs) with particle sizes between 10 nm and 60 nm. The biocompatible magnetic nanoparticles are produced from Magnetospirillum magneticum (M.M.) bacteria that respond to magnetic fields. M.M. bacteria were cultured and used to synthesize magnetite nanoparticles. This was done in an enriched magnetic spirillum growth medium (EMSGM) at different pH levels. The nanoparticle concentrations were characterized with UV-Visible (UV-Vis) spectroscopy, while the particle shapes were elucidated via transmission electron microscopy (TEM). The structure of the particles was studied using X-ray diffraction (XRD), while the hydrodynamic radii, particle size distributions and polydispersity of the nanoparticles were characterized using dynamic light scattering (DLS). Carbodiimide reduction was also used to functionalize the BMNPs with a molecular recognition unit (luteinizing hormone releasing hormone, LHRH) that attaches specifically to receptors that are over-expressed on the surfaces of most breast cancer cell types. The resulting nanoparticles were examined using Fourier Transform Infrared (FTIR) spectroscopy and quantitative image analysis. The implications of the results are then discussed for the potential development of magnetic nanoparticles for the specific targeting and treatment of breast cancer. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. [Effectiveness of skin icing for reducing pain associated with luteinizing hormone-releasing hormone agonist injection].

    Science.gov (United States)

    Nomura, Tsunehisa; Tsunoda, Kazuko; Ohta, Satoko; Doi, Katsumi; Miyoshi, Kazuya; Hasegawa, Yasuhisa; Mizutani, Masami

    2014-02-01

    We evaluated the effect of using the cooling method on pain at the site of luteinizing hormone-releasing hormone(LH-RH) agonist injection in 181 prostate cancer or premenopausal breast cancer patients by using a numerical rating scale(NRS)and a questionnaire survey with open-ended questions. According to the NRS, 38.1% of the patients experienced a reduction in pain, 37.5% experienced no change, and 24.4% experienced an increase in pain. Therefore, use of the cooling method did not have a statistically significant effect in terms of pain reduction(p=0.123). However, on analyzing pain reduction according to the answers in the questionnaire survey, 53.2% of the patients experienced a reduction in pain, 38.5% experienced no change, and 8.3% experienced an increase in pain. These findings were different from those obtained on using the NRS. In addition, irrespective of using the cooling method, needle thickness and patient obesity strongly influenced the pain experienced. The skin icing method was effective in reducing pain at the site of LH-RH agonist injection. This method is simple, inexpensive, and safe, and is hence recommended.

  16. Ghrelin stimulation of growth hormone-releasing hormone neurons is direct in the arcuate nucleus.

    Directory of Open Access Journals (Sweden)

    Guillaume Osterstock

    2010-02-01

    Full Text Available Ghrelin targets the arcuate nucleus, from where growth hormone releasing hormone (GHRH neurones trigger GH secretion. This hypothalamic nucleus also contains neuropeptide Y (NPY neurons which play a master role in the effect of ghrelin on feeding. Interestingly, connections between NPY and GHRH neurons have been reported, leading to the hypothesis that the GH axis and the feeding circuits might be co-regulated by ghrelin.Here, we show that ghrelin stimulates the firing rate of identified GHRH neurons, in transgenic GHRH-GFP mice. This stimulation is prevented by growth hormone secretagogue receptor-1 antagonism as well as by U-73122, a phospholipase C inhibitor and by calcium channels blockers. The effect of ghrelin does not require synaptic transmission, as it is not antagonized by gamma-aminobutyric acid, glutamate and NPY receptor antagonists. In addition, this hypothalamic effect of ghrelin is independent of somatostatin, the inhibitor of the GH axis, since it is also found in somatostatin knockout mice. Indeed, ghrelin does not modify synaptic currents of GHRH neurons. However, ghrelin exerts a strong and direct depolarizing effect on GHRH neurons, which supports their increased firing rate.Thus, GHRH neurons are a specific target for ghrelin within the brain, and not activated secondary to altered activity in feeding circuits. These results support the view that ghrelin related therapeutic approaches could be directed separately towards GH deficiency or feeding disorders.

  17. In vivo pharmacological evaluation of a lactose-conjugated luteinizing hormone releasing hormone analogue.

    Science.gov (United States)

    Moradi, Shayli Varasteh; Varamini, Pegah; Steyn, Frederik; Toth, Istvan

    2015-11-10

    In the current study, the efficacy and pharmacokinetic profile of lactose-conjugated luteinizing hormone releasing hormone (LHRH) was examined following oral administration in male rats. A rapid and sensitive liquid chromatography/mass spectrometry technique was developed and applied for measuring the concentration of lactose[Q(1)][w(6)]LHRH (compound 1) in rat plasma in order to allow measurement of pharmacokinetic parameters. LH release was evaluated using a sandwich ELISA. Maximum serum concentration (Cmax = 0.11 μg/ml) was reached at 2h (Tmax) following oral administration of the compound at 10mg/kg. The half-life was determined to be 2.6h. The absolute bioavailability of the orally administered compound was found to be 14%, which was a remarkable improvement compared to zero-to-low oral bioavailability of the native peptide. Compound 1 was effective in stimulating LH release at 20mg/kg after oral administration. The method was validated at a linear range of 0.01-20.0 μg/ml and a correlation coefficient of r(2) ≥ 0.999. The accuracy and precision values showed the reliability and reproducibility of the method for evaluation of the pharmacokinetic parameters. These findings showed that the lactose derivative of LHRH has a therapeutic potential to be further developed as an orally active therapeutics for the treatment of hormone-dependent diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Biosynthesis and the conjugation of magnetite nanoparticles with luteinizing hormone releasing hormone (LHRH)

    Energy Technology Data Exchange (ETDEWEB)

    Obayemi, J.D. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Materials Science and Engineering, Kwara State University, Malete, Kwara State (Nigeria); Dozie-Nwachukwu, S. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Sheda Science and Technology Complex (SHESTCO) Abuja, Federal Capital Territory (Nigeria); Danyuo, Y. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Department of Electronics and Electricals Engineering, Nigerian Turkish Nile University, Abuja (Nigeria); Odusanya, O.S. [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Sheda Science and Technology Complex (SHESTCO) Abuja, Federal Capital Territory (Nigeria); Anuku, N. [Department of Chemistry, Bronx Community College, New York, NY 10453 (United States); Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Malatesta, K. [Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544 (United States); Soboyejo, W.O., E-mail: soboyejo@princeton.edu [Department of Materials Science and Engineering, African University of Science and Technology (AUST) Abuja, Federal Capital Territory (Nigeria); Princeton Institute of Science and Technology of Materials (PRISM), Princeton, NJ 08544 (United States); Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08544 (United States)

    2015-01-01

    This paper presents the results of an experimental study of the biosynthesis of magnetite nanoparticles (BMNPs) with particle sizes between 10 nm and 60 nm. The biocompatible magnetic nanoparticles are produced from Magnetospirillum magneticum (M.M.) bacteria that respond to magnetic fields. M.M. bacteria were cultured and used to synthesize magnetite nanoparticles. This was done in an enriched magnetic spirillum growth medium (EMSGM) at different pH levels. The nanoparticle concentrations were characterized with UV–Visible (UV–Vis) spectroscopy, while the particle shapes were elucidated via transmission electron microscopy (TEM). The structure of the particles was studied using X-ray diffraction (XRD), while the hydrodynamic radii, particle size distributions and polydispersity of the nanoparticles were characterized using dynamic light scattering (DLS). Carbodiimide reduction was also used to functionalize the BMNPs with a molecular recognition unit (luteinizing hormone releasing hormone, LHRH) that attaches specifically to receptors that are over-expressed on the surfaces of most breast cancer cell types. The resulting nanoparticles were examined using Fourier Transform Infrared (FTIR) spectroscopy and quantitative image analysis. The implications of the results are then discussed for the potential development of magnetic nanoparticles for the specific targeting and treatment of breast cancer. - Highlights: • Biosynthesis of MNPs with clinically relevant sizes between 10 and 60 nm. • New insights into the effects of pH and processing time on nanoparticle shapes and sizes. • Successful conjugation of biosynthesized magnetite nanoparticles to LHRH ligands. • Conjugated BMNPs that are monodispersed with potential biomedical relevance. • Magnetic properties of biosynthesized MNPs suggest potential for MRI enhancement.

  19. The effects of kisspeptin-10 on reproductive hormone release show sexual dimorphism in humans.

    Science.gov (United States)

    Jayasena, Channa N; Nijher, Gurjinder M K; Comninos, Alexander N; Abbara, Ali; Januszewki, Adam; Vaal, Meriel L; Sriskandarajah, Labosshy; Murphy, Kevin G; Farzad, Zohreh; Ghatei, Mohammad A; Bloom, Stephen R; Dhillo, Waljit S

    2011-12-01

    Kisspeptin peptides are critical in human reproductive physiology and are potential therapies for infertility. Kisspeptin-10 stimulates gonadotropin release in both male and female rodents. However, few studies have investigated the effects of kisspeptin-10 on gonadotropin release in humans, and none have investigated the effect in women. If kisspeptin is to be useful for treating reproductive disease, its effects in both men and women must be established. To compare the effects of kisspeptin-10 administration on reproductive hormone release in healthy men and women. Intravenous bolus kisspeptin-10 was administered to men and women (n = 4-5 per group). Subcutaneous bolus and i.v. infusion of kisspeptin-10 was also administered to female women (n = 4-5 per group). Circulating reproductive hormones were measured. In healthy men, serum LH and FSH were elevated after i.v. bolus kisspeptin-10, at doses as low as 0.3 and 1.0 nmol/kg, respectively. In healthy women during the follicular phase of the menstrual cycle, no alterations in serum gonadotropins were observed after i.v. bolus, s.c. bolus, or i.v. infusion of kisspeptin-10 at maximal doses of 10 nmol/kg, 32 nmol/kg, and 720 pmol/kg/min, respectively. In women during the preovulatory phase, serum LH and FSH were elevated after i.v. bolus kisspeptin-10 (10 nmol/kg). Kisspeptin-10 stimulates gonadotropin release in men as well as women during the preovulatory phase of menstrual cycle but fails to stimulate gonadotropin release in women during the follicular phase. The sexual dimorphism of the responsiveness of healthy men and women to kisspeptin-10 administration has important clinical implications for the potential of kisspeptin-10 to treat disorders of reproduction.

  20. Growth hormone-releasing hormone antagonists inhibit growth of human ovarian cancer.

    Science.gov (United States)

    Papadia, A; Schally, A V; Halmos, G; Varga, J L; Seitz, S; Buchholz, S; Rick, F; Zarandi, M; Bellyei, S; Treszl, A; Szalontay, L; Lucci, J A

    2011-10-01

    Epithelial ovarian carcinoma is the leading cause of cancer-related deaths among women with gynecologic malignancies. Antagonists of the growth hormone-releasing hormone (GHRH) have been shown to inhibit growth of various cancers through endocrine, autocrine, and paracrine mechanisms. In this study, we have investigated the effects of GHRH antagonists (GHRHa) in ES-2 human clear cell ovarian cancer and in UCI-107 human serous ovarian cancer in vitro and in vivo. We evaluated the expression of mRNA for GHRH receptor, the binding to GHRH receptors, in specimens of ES-2 ovarian cancer. We evaluated also the in vitro effects of GHRHa on ES-2 cells and the in vivo effect of 2 different GHRHa on ES-2 and UCI-107 tumors. Nude mice bearing xenografts on ES-2 and UCI-107 ovarian cancer were treated with JMR-132 and MZ-J-7-118, respectively. Tumor growth was compared to control. ES-2 cells expressed mRNA for the functional splice variant SV1 of the GHRH receptor. JMR-132 inhibited cell proliferation in vitro by 42% and 18% at 10 and 1 μM concentration, respectively. Specific high affinity receptors for GHRH were detected in ES-2 cancer samples. In vivo daily subcutaneous injections of GHRHa significantly reduced tumor growth compared to a control group in both animal models. Our results indicate that GHRHa such as JMR-132 and MZ-J-7-118 can inhibit the growth of human ovarian cancer. The efficacy of GHRHa in ovarian cancer should be assessed in clinical trials. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Antagonists of growth hormone-releasing hormone inhibit the proliferation of experimental non-small cell lung carcinoma.

    Science.gov (United States)

    Szereday, Zoltan; Schally, Andrew V; Varga, Jozsef L; Kanashiro, Celia A; Hebert, Francine; Armatis, Patricia; Groot, Kate; Szepeshazi, Karoly; Halmos, Gabor; Busto, Rebeca

    2003-11-15

    Recent studies show that antagonists of growth hormone-releasing hormone (GH-RH) inhibit proliferation of various cancers indirectly through blockage of the endocrine GH-insulin-like growth factor (IGF) I axis and directly by an action on tumor cells involving the suppression of autocrine/paracrine IGF-I, IGF-II, or GH-RH. The effectiveness of therapy with GH-RH antagonist JV-1-38 and its mechanisms of action were investigated in NCI-H838 non-small cell lung carcinoma (NSCLC) xenografted s.c. into nude mice and in vitro. Treatment with GH-RH antagonist JV-1-38 significantly (P < 0.05-0.001) inhibited tumor growth as demonstrated by a 58% decrease in final tumor volume, 54% reduction in tumor weight, and the extension of tumor-doubling time from 8.5 +/- 1.38 to 12 +/- 1.07 days as compared with controls. Using ligand competition assays with (125)I-labeled GH-RH antagonist JV-1-42, specific high-affinity binding sites for GH-RH were found on tumor membranes. Reverse transcription-PCR revealed the expression of mRNA for GH-RH and splice variant 1 (SV(1)) of GH-RH receptor in H838 tumors. Reverse transcription-PCR analysis also demonstrated that H838 tumors express IGF-I and IGF-I receptors. Tumoral concentration of IGF-I and its mRNA expression were significantly decreased by 25% (P = 0.05) and 65% (P < 0.001), respectively, in animals receiving JV-1-38, whereas serum IGF-I levels remained unchanged. In vitro studies showed that H838 cells secreted GH-RH and IGF-I into the medium. The growth of tumor cells in vitro was stimulated by IGF-I and inhibited by GH-RH antagonist JV-1-38 and a GH-RH antiserum. Our results extend the findings on the involvement of IGF-I in NSCLC and suggest that GH-RH may be an autocrine growth factor for H838 NSCLC. The antitumorigenic action of GH-RH antagonists could be partly direct and mediated by SV(1) of tumoral GH-RH receptors. The finding of GH-RH and SV(1) of GH-RH receptors in NSCLC provides a new approach to the treatment of this

  2. Sleep in mice with nonfunctional growth hormone-releasing hormone receptors.

    Science.gov (United States)

    Obal, Ferenc; Alt, Jeremiah; Taishi, Ping; Gardi, Janos; Krueger, James M

    2003-01-01

    The role of the somatotropic axis in sleep regulation was studied by using the lit/lit mouse with nonfunctional growth hormone (GH)-releasing hormone (GHRH) receptors (GHRH-Rs) and control heterozygous C57BL/6J mice, which have a normal phenotype. During the light period, the lit/lit mice displayed significantly less spontaneous rapid eye movement sleep (REMS) and non-REMS (NREMS) than the controls. Intraperitoneal injection of GHRH (50 microg/kg) failed to promote sleep in the lit/lit mice, whereas it enhanced NREMS in the heterozygous mice. Subcutaneous infusion of GH replacement stimulated weight gain, increased the concentration of plasma insulin-like growth factor-1 (IGF-1), and normalized REMS, but failed to restore normal NREMS in the lit/lit mice. The NREMS response to a 4-h sleep deprivation was attenuated in the lit/lit mice. In control mice, intraperitoneal injection of ghrelin (400 microg/kg) elicited GH secretion and promoted NREMS, and intraperitoneal administration of the somatostatin analog octretotide (Oct, 200 microg/kg) inhibited sleep. In contrast, these responses were missing in the lit/lit mice. The results suggest that GH promotes REMS whereas GHRH stimulates NREMS via central GHRH-Rs and that GHRH is involved in the mediation of the sleep effects of ghrelin and somatostatin.

  3. Simultaneous measurement of hormone release and secretagogue binding by individual pituitary cells

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.F.; Neill, J.D.

    1987-08-01

    The quantitative relationship between receptor binding and hormone secretion at the single-cell level was investigated in the present study by combining a reverse hemolytic plaque assay for measurement of luteinizing hormone (LH) secretion from individual pituitary cells with an autoradiographic assay of /sup 125/I-labeled gonadontropin-releasing hormone (GnRH) agonist binding to the same cells. In the plaque assay, LH secretion induces complement-mediated lysis of the LH-antibody-coated erythrocytes around the gonadotropes, resulting in areas of lysis (plaques). LH release from individual gonadotropes was quantified by comparing radioimmunoassayable LH release to hemolytic area in similarly treated cohort groups of cells; plaque area was linearly related to the amount of LH secreted. Receptor autoradiography was performed using /sup 125/I-labeled GnRH-A (a superagonist analog of GnRH) both as the ligand and as the stimulant for LH release in the plaque assay. The grains appeared to represent specific and high-affinity receptors for GnRH because (i) no pituitary cells other than gonadotropes bound the labeled ligand and (ii) grain development was progressively inhibited by coincubation with increasing doses of unlabeled GnRH-A. The authors conclude that GnRH receptor number for any individual gonadotrope is a weak determinant of the amount of LH it can secrete; nevertheless, full occupancy of all its GnRH receptors is required for any gonadotrope to reach its full LH-secretory capacity. Apparently the levels of other factors comprising the steps along the secretory pathway determine the secretory capacity of an individual cell.

  4. Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data.

    Science.gov (United States)

    Falutz, Julian; Mamputu, Jean-Claude; Potvin, Diane; Moyle, Graeme; Soulban, Graziella; Loughrey, Helen; Marsolais, Christian; Turner, Ralph; Grinspoon, Steven

    2010-09-01

    HIV patients treated with antiretroviral therapy (ART) often develop increased visceral adipose tissue (VAT). Our objective was to perform a pooled analysis of two phase-3 studies of tesamorelin in ART-treated HIV patients with excess abdominal fat. Two multicenter, international studies were conducted; a 26-wk randomized, placebo-controlled primary intervention phase was followed by a 26-wk safety extension. A total of 806 ART-treated HIV patients with excess abdominal fat were randomized in a 2:1 fashion to receive tesamorelin 2 mg (n = 543) or placebo (n = 263) sc daily. At wk 26, patients initially on tesamorelin were rerandomized to 2 mg tesamorelin (T-T group, n = 246) or placebo (T-P, n = 135) for an additional 26 wk, whereas patients on placebo were switched to tesamorelin (P-T, n = 197). Tesamorelin (GHRH(1-44)) at a dose of 2 mg or identical placebo, sc, was given daily. We evaluated percent change in VAT by computed tomography scan at wk 26. At wk 26, VAT decreased significantly in tesamorelin-treated patients (-24 +/- 41 vs. 2 +/- 35 cm(2), tesamorelin vs. placebo, P body image [belly appearance distress (P = 0.002)], patient rating of belly profile (P = 0.003), and physician rating of belly profile (P body image and lipids, and is overall well tolerated without clinically meaningful changes in glucose parameters.

  5. HORMONE THERAPY WITH USAGE OF AGONISTS AND ANTAGONISTS OF LUTEINIZING HORMONE RELEASING HORMONE IN PATIENTS WITH PROSTATE CANCER

    Directory of Open Access Journals (Sweden)

    K. M. Nyushko

    2014-01-01

    Full Text Available Prostate cancer (PC is one of the most actual problems of modern oncourology. Hormone therapy (HT using medical castration is the main method of treatment of patients with metastatic PC. HT with usage of the new class of drugs that block the receptors for luteinizing hormone releasing hormone (LHRH is a promising and effective method of castration therapy that has a number of significant advantages over the use of analogues LHRH. This article presents areview of studies that compared the effectiveness and side effects of HT using antagonists and analogues LHRH.

  6. Activation of arcuate nucleus neurons by systemic administration of leptin and growth hormone-releasing peptide-6 in normal and fasted rats.

    Science.gov (United States)

    Luckman, S M; Rosenzweig, I; Dickson, S L

    1999-08-01

    Both leptin and growth hormone secretagogues are believed to have stimulatory effects on the hypothalamic growth hormone pulse generator, though whether these are achieved through the same pathway is unknown. Systemic administration of a normally maximal effective dose of the growth hormone secretagogue GHRP-6 to male rats causes the induction of c-Fos protein in the ventromedial aspect of the hypothalamic arcuate nucleus. The effect of the same dose of GHRP-6 is, however, much greater in animals that have been fasted for 48 h, suggesting that in the food-replete rat, arcuate neurons either show reduced sensitivity to endogenous growth hormone secretagogues or they are under the tonic inhibitory influences of other factors. The major populations of arcuate neurons activated by GHRP-6 have been shown to contain neuropeptide Y or growth hormone-releasing factor, while leptin is thought to be inhibitory to neuropeptide Y neurons. Leptin did not alter the response of the rats to GHRP-6. However, it was able by itself to induce c-Fos protein immunoreactivity in the ventral, including the ventrolateral, arcuate nucleus of fasted rats. This is a clear demonstration of the acute activation of arcuate neurons in the rat following systemic leptin injection and suggests that GHRP-6 and leptin act on the growth hormone axis via different pathways.

  7. A prospective examination of risk factors in the development of intrusions following a trauma analog.

    Science.gov (United States)

    Ripley, Adam J; Clapp, Joshua D; Beck, J Gayle

    2017-07-01

    Several factors have been linked to the severity of posttraumatic distress, although retrospective designs in much of the literature limit conclusions regarding the temporal relation between risk factors and corresponding symptoms. To address these concerns, the current project employed an analog trauma paradigm to assess the impact of background characteristics, stress response, and post-stressor affect regulation on subjective distress and intrusive memories experienced during the subsequent processing of emotional stimuli. University students (N = 184; 56% female, 42% White/Non-Hispanic) were shown graphic scenes of a televised suicide. Physiological activation was recorded during exposure with emotion ratings collected following the film. Participants then viewed a sadness- or humor-eliciting prime under instructions to inhibit or naturally express emotion. Intrusions experienced during the priming film and residual distress at study's conclusion were rated prior to debriefing. Hierarchical regression identified reductions in emotional valence as a robust predictor of intrusions and distress. Sympathetic activation and exposure to the sadness prime were associated with intrusion frequency, whereas attenuated parasympathetic response predicted intrusion intensity. Expressive inhibition demonstrated a unique association with residual distress. Results suggest peritraumatic processes and post-exposure factors may hold more prominent relations with immediate trauma-related distress as compared to pre-existing survivor characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Inhibition of growth and reduction in tumorigenicity of UCI-107 ovarian cancer by antagonists of growth hormone-releasing hormone and vasoactive intestinal peptide.

    Science.gov (United States)

    Chatzistamou, I; Schally, A V; Varga, J L; Groot, K; Armatis, P; Bajo, A M

    2001-11-01

    To evaluate the tumor inhibitory activities of antagonists of growth hormone-releasing hormone (GH-RH) and vasoactive intestinal peptide (VIP) in UCI-107 human ovarian cancer model, and to investigate the role of the insulin-like growth factor (IGF) system in the response. In the present study we investigated the effects of GH-RH antagonist JV-1-36 and VIP antagonist JV-1-52, on the growth and tumorigenicity of UCI-107 ovarian cell carcinoma xenografted into nude mice. Studies on the effects of hGH-RH(1-29)NH2, IGF-I, IGF-II, JV-1-36, and JV-1-52 on the proliferation of UCI-107 cells cultured in vitro were also performed. After 22 days of therapy with JV-1-36 or JV-1-52 at the dose of 20 microg/day, the final volume of UCI-107 tumors was significantly (PUCI-107 cells in nude mice. All ten mice injected with cells treated with medium alone developed tumors within 23 days after cell inoculation, while only eight of ten and four of ten mice injected with cells exposed to JV-1-36 or JV-1-52, respectively, had tumors. In vitro exposure of UCI-107 cells to 5-35 ng/ml IGF-II produced a significant suppression in the rate of cell proliferation (P UCI-107 ovarian cell carcinoma by mechanisms that appear to involve direct effects on the cancer cells.

  9. Effects of administration of two growth hormone-releasing hormone plasmids to gilts on sow and litter performance for the subsequent three gestations.

    Science.gov (United States)

    Brown, Patricia A; Khan, Amir S; Draghia-Akli, Ruxandra; Pope, Melissa A; Bodles-Brakhop, Angela M; Kern, Douglas R

    2012-09-01

    To determine whether a novel optimized plasmid carrying the porcine growth hormone-releasing hormone (GHRH) wild-type cDNA administered at a lower dose was as effective at eliciting physiologic responses as a commercial GHRH plasmid approved for use in Australia. 134 gilts. Estrus was synchronized and gilts were bred. Pregnant gilts were assigned to 2 treatment groups (40 gilts/group) or 1 untreated control group (24 gilts). Gilts in one of the treatment groups received the commercial GHRH plasmid, whereas gilts in the other treatment group received a novel optimized GHRH plasmid; both plasmids were administered IM in the right hind limb, which was followed by electroporation. Sow and litter performance were monitored for the 3 gestations after treatment. A significant increase in insulin-like growth factor-I concentrations, decrease in perinatal mortality rate, increase in the number of pigs born alive, and increase in the weight and number of pigs weaned were detected for both groups receiving the GHRH-expressing plasmids, compared with values for the control group. Additionally, there was a significant decrease in sow attrition in GHRH-treated females, compared with attrition in the control group, during the 3 gestations after treatment. Both of the GHRH plasmids provided significant benefits for sow performance and baby pig survivability for pregnant and lactating sows and their offspring during the 3 gestations after treatment, compared with results for untreated control gilts. Use of a novel optimized plasmid reduced the effective plasmid dose in these large mammals.

  10. [Direct and indirect costs of luteinising hormone-releasing hormone analogues in the treatment of locally advanced or metastatic prostate cancer in Italy].

    Science.gov (United States)

    Fadda, Valeria; Maratea, Dario

    2015-12-01

    When analyzing the use of luteinizing hormone-releasing hormone (LHRH) analogues for different clinical indications, current available evidence does not support a presumed drug class effect among the various LHRH in the treatment of prostate cancer. The following search key words were entered in the PubMed database and the NICE and FDA websites: “LHRH agonist AND prostatic cancer”, “androgen deprivation therapy”, “androgen suppression”, “buserelin”, “leuprorelin”, “goserelin”,“triptorelin”, “degarelix”. The direct costs included the following items: follow-up visits, diagnostic exams (e.g. prostate-specific antigen PSA) and drug costs. The indirect costs included working days lost by the patient. With intermittent therapy as a reference, leuprorelin injectable solution of 22,25 mg was associated with the lowest cost and degarelix with the highest cost. However, given the mandatory presence of a nurse for drug injection, the buserelin depot formulation was associated with the lowest cost. If the costs for hospital visits were added to drug costs, differences between the various therapeutic strategies were less remarkable. Our study showed how various factors (e.g. route of administration, frequency of administration, presence of a nurse for drug reconstitution and injection) should be taken into account by decision makers in addition to the price of drugs.

  11. New monocyte locomotion inhibitory factor analogs protect against cerebral ischemia-reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Xiaoping Wang

    2017-08-01

    Full Text Available Monocyte locomotion inhibitory factor (MLIF is an oligopeptide with anti-inflammatory properties. The carboxyl-terminal end group Cys-Asn-Ser serves as the pharmacophore of MLIF. The aim of this study was to investigate the neuroprotective effects of two new synthetic analogs, Arg-Cys-Asn-Ser and D-Cys-Asn-Ser, on focal cerebral ischemia, which were designed and synthesized to increase the penetrability and enzymatic stability of Cys-Asn-Ser. Ninety-one male Sprague-Dawley rats were randomly divided into six groups: I - Sham; II - Ischemia-reperfusion (I/R; III - Nimodipine; IV - Cys-Asn-Ser; V - D-Cys-Asn-Ser; and VI - Arg-Cys-Asn-Ser. The rats in groups II-VI were subjected to middle cerebral artery occlusion. After 24 hours of reperfusion, the neurological deficit, cerebral infarct volume, and levels of the pro-inflammatory factors interleukin-1β (IL-1β and tumor necrosis factor-alpha in brain tissue homogenates were assessed. Compared with the sham group, the mean neurological deficit scores were significantly higher in groups II-VI (p ≤ 0.019 for all. The mean infarct volumes were significantly higher in I/R and Cys-Asn-Ser groups compared with the sham group (both p ≤ 0.046. The mean IL-1β level was significantly lower in D-Cys-Asn-Ser and Arg-Cys-Asn-Ser groups compared with I/R group (both p ≤ 0.046. In conclusion, the results showed that Arg-Cys-Asn-Ser and D-Cys-Asn-Ser have the potential for protective effects against focal cerebral ischemia injury.

  12. Relationship between body mass index and serum testosterone concentration in patients receiving luteinizing hormone-releasing hormone agonist therapy for prostate cancer

    NARCIS (Netherlands)

    van der Sluis, Tim M.; van Moorselaar, R. Jeroen A.; Meuleman, Eric J. H.; ter Haar, Ronald W.; Bui, Hong N.; Heijboer, Annemieke C.; Vis, André N.

    2013-01-01

    To evaluate the relationship between the body mass index (BMI) and serum testosterone concentrations in men receiving luteinizing hormone-releasing hormone (LHRH) agonist therapy for prostate cancer. A total of 66 white men were included in the present study. All subjects had received LHRH agonist

  13. Degarelix monotherapy compared with luteinizing hormone-releasing hormone (LHRH) agonists plus anti-androgen flare protection in advanced prostate cancer

    DEFF Research Database (Denmark)

    Iversen, Peter; Damber, Jan Erik; Malmberg, Anders

    2016-01-01

    OBJECTIVES: The objective of this study was to assess differences in efficacy outcomes between luteinizing hormone-releasing hormone (LHRH) agonist plus antiandrogen (AA) flare protection and monotherapy with the gonadotrophin-releasing hormone antagonist degarelix in patients with prostate cancer...

  14. Understanding the multifactorial control of growth hormone release by somatotropes: lessons from comparative endocrinology.

    Science.gov (United States)

    Gahete, Manuel D; Durán-Prado, Mario; Luque, Raúl M; Martínez-Fuentes, Antonio J; Quintero, Ana; Gutiérrez-Pascual, Ester; Córdoba-Chacón, José; Malagón, María M; Gracia-Navarro, Francisco; Castaño, Justo P

    2009-04-01

    Control of postnatal growth is the main, but not the only, role for growth hormone (GH) as this hormone also contributes to regulating metabolism, reproduction, immunity, development, and osmoregulation in different species. Likely owing to this variety of group-specific functions, GH production is differentially regulated across vertebrates, with an apparent evolutionary trend to simplification, especially in the number of stimulatory factors governing substantially GH release. Thus, teleosts exhibit a multifactorial regulation of GH secretion, with a number of factors, from the newly discovered fish GH-releasing hormone (GHRH) to pituitary adenylate cyclase-activating peptide (PACAP) but also gonadotropin-releasing hormone, dopamine, corticotropin-releasing hormone, and somatostatin(s) directly controlling somatotropes. In amphibians and reptiles, GH secretion is primarily stimulated by the major hypothalamic peptides GHRH and PACAP and inhibited by somatostatin(s), while other factors (ghrelin, thyrotropin-releasing hormone) also influence GH release. Finally, in birds and mammals, primary control of GH secretion is exerted by a dual interplay between GHRH and somatostatin. In addition, somatotrope function is modulated by additional hypothalamic and peripheral factors (e.g., ghrelin, leptin, insulin-like growth factor-I), which together enable a balanced integration of feedback signals related to processes in which GH plays a relevant regulatory role, such as metabolic and energy status, reproductive, and immune function. Interestingly, in contrast to the high number of stimulatory factors impinging upon somatotropes, somatostatin(s) stand(s) as the main primary inhibitory regulator(s) for this cell type.

  15. Effects of growth hormone-releasing hormone on sleep and brain interstitial fluid amyloid-β in an APP transgenic mouse model.

    Science.gov (United States)

    Liao, Fan; Zhang, Tony J; Mahan, Thomas E; Jiang, Hong; Holtzman, David M

    2015-07-01

    Alzheimer's disease (AD) is a neurodegenerative disorder characterized by impairment of cognitive function, extracellular amyloid plaques, intracellular neurofibrillary tangles, and synaptic and neuronal loss. There is substantial evidence that the aggregation of amyloid β (Aβ) in the brain plays a key role in the pathogenesis of AD and that Aβ aggregation is a concentration dependent process. Recently, it was found that Aβ levels in the brain interstitial fluid (ISF) are regulated by the sleep-wake cycle in both humans and mice; ISF Aβ is higher during wakefulness and lower during sleep. Intracerebroventricular infusion of orexin increased wakefulness and ISF Aβ levels, and chronic sleep deprivation significantly increased Aβ plaque formation in amyloid precursor protein transgenic (APP) mice. Growth hormone-releasing hormone (GHRH) is a well-documented sleep regulatory substance which promotes non-rapid eye movement sleep. GHRHR(lit/lit) mice that lack functional GHRH receptor have shorter sleep duration and longer wakefulness during light periods. The current study was undertaken to determine whether manipulating sleep by interfering with GHRH signaling affects brain ISF Aβ levels in APPswe/PS1ΔE9 (PS1APP) transgenic mice that overexpress mutant forms of APP and PSEN1 that cause autosomal dominant AD. We found that intraperitoneal injection of GHRH at dark onset increased sleep and decreased ISF Aβ and that delivery of a GHRH antagonist via reverse-microdialysis suppressed sleep and increased ISF Aβ. The diurnal fluctuation of ISF Aβ in PS1APP/GHRHR(lit/lit) mice was significantly smaller than that in PS1APP/GHRHR(lit/+) mice. However despite decreased sleep in GHRHR deficient mice, this was not associated with an increase in Aβ accumulation later in life. One of several possibilities for the finding is the fact that GHRHR deficient mice have GHRH-dependent but sleep-independent factors which protect against Aβ deposition. Copyright © 2014

  16. Circadian and sleep-dependent regulation of hormone release in humans

    Science.gov (United States)

    Czeisler, C. A.; Klerman, E. B.

    1999-01-01

    Daily oscillations characterize the release of nearly every hormone. The circadian pacemaker, located in the suprachiasmatic nucleus of the hypothalamus, generates circadian, approximately 24-hour rhythms in many physiologic functions. However, the observed hormonal oscillations do not simply reflect the output of this internal clock. Instead, daily hormonal profiles are the product of a complex interaction between the output of the circadian pacemaker, periodic changes in behavior, light exposure, neuroendocrine feedback mechanisms, gender, age, and the timing of sleep and wakefulness. The interaction of these factors can affect hormonal secretory pulse frequency and amplitude, with each endocrine system differentially affected by these factors. This chapter examines recent advances in understanding the effects on endocrine rhythms of a number of these factors. Sleep exerts a profound effect on endocrine secretion. Sleep is a dynamic process that is characterized by periodic changes in electrophysiologic activity. These electrophysiologic changes, which are used to mark the state and depth of sleep, are associated with periodic, short-term variations in hormonal levels. The secretion of hormones such as renin and human growth hormone are strongly influenced by sleep or wake state, while melatonin and cortisol levels are relatively unaffected by sleep or wake state. In addition, sleep is associated with changes in posture, behavior, and light exposure, each of which is known to affect endocrine secretion. Furthermore, the tight concordance of habitual sleep and wake times with certain circadian phases has made it difficult to distinguish sleep and circadian effects on these hormones. Specific protocols, designed to extract circadian and sleep information semi-independently, have been developed and have yielded important insights into the effects of these regulatory processes. These results may help to account for changes in endocrine rhythms observed in circadian

  17. Aging influences steroid hormone release by mink ovaries and their response to leptin and IGF-I

    Directory of Open Access Journals (Sweden)

    Alexander V. Sirotkin

    2016-02-01

    Full Text Available The aim of our study was to understand whether ovarian steroid hormones, and their response to the metabolic hormones leptin and IGF-I leptin, could be involved in the control of mink reproductive aging via changes in basal release of ovarian progesterone and estradiol. For this purpose, we compared the release of progesterone and estradiol by ovarian fragments isolated from young (yearlings and old (3-5 years of age minks cultured with and without leptin and IGF-I (0, 1, 10 or 100 ng/ml. We observed that isolated ovaries of older animals produced less progesterone but not less estradiol than the ovaries of young animals. Leptin addition stimulated estradiol release by the ovarian tissue of young animals but inhibited it in older females. Leptin did not influence progesterone output by the ovaries of either young or older animals. IGF-I inhibited estradiol output in young but not old animals, whereas progesterone release was inhibited by IGF-I irrespective of the animal age. Our observations demonstrate the involvement of both leptin and IGF-I in the control of mink ovarian steroid hormones release. Furthermore, our findings suggest that reproductive aging in minks can be due to (a reduction in basal progesterone release and (b alterations in the response of estradiol but not of progesterone to leptin and IGF-I.

  18. Structural and functional divergence of growth hormone-releasing hormone receptors in early sarcopterygians: lungfish and Xenopus.

    Directory of Open Access Journals (Sweden)

    Janice K V Tam

    Full Text Available The evolutionary trajectories of growth hormone-releasing hormone (GHRH receptor remain enigmatic since the discovery of physiologically functional GHRH-GHRH receptor (GHRHR in non-mammalian vertebrates in 2007. Interestingly, subsequent studies have described the identification of a GHRHR(2 in chicken in addition to the GHRHR and the closely related paralogous receptor, PACAP-related peptide (PRP receptor (PRPR. In this article, we provide information, for the first time, on the GHRHR in sarcopterygian fish and amphibians by the cloning and characterization of GHRHRs from lungfish (P. dolloi and X. laevis. Sequence alignment and phylogenetic analyses demonstrated structural resemblance of lungfish GHRHR to their mammalian orthologs, while the X. laevis GHRHR showed the highest homology to GHRHR(2 in zebrafish and chicken. Functionally, lungfish GHRHR displayed high affinity towards GHRH in triggering intracellular cAMP and calcium accumulation, while X. laevis GHRHR(2 was able to react with both endogenous GHRH and PRP. Tissue distribution analyses showed that both lungfish GHRHR and X. laevis GHRHR(2 had the highest expression in brain, and interestingly, X. laevis(GHRHR2 also had high abundance in the reproductive organs. These findings, together with previous reports, suggest that early in the Sarcopterygii lineage, GHRHR and PRPR have already established diverged and specific affinities towards their cognate ligands. GHRHR(2, which has only been found in xenopus, zebrafish and chicken hitherto, accommodates both GHRH and PRP.

  19. A role for central nervous growth hormone-releasing hormone signaling in the consolidation of declarative memories.

    Directory of Open Access Journals (Sweden)

    Manfred Hallschmid

    Full Text Available Contributions of somatotropic hormonal activity to memory functions in humans, which are suggested by clinical observations, have not been systematically examined. With previous experiments precluding a direct effect of systemic growth hormone (GH on acute memory formation, we assessed the role of central nervous somatotropic signaling in declarative memory consolidation. We examined the effect of intranasally administered growth hormone releasing-hormone (GHRH; 600 µg that has direct access to the brain and suppresses endogenous GHRH via an ultra-short negative feedback loop. Twelve healthy young men learned word-pair associates at 2030 h and were administered GHRH and placebo, respectively, at 2100 h. Retrieval was tested after 11 hours of wakefulness. Compared to placebo, intranasal GHRH blunted GH release within 3 hours after substance administration and reduced the number of correctly recalled word-pairs by ∼12% (both P<0.05. The impairment of declarative memory consolidation was directly correlated to diminished GH concentrations (P<0.05. Procedural memory consolidation as examined by the parallel assessment of finger sequence tapping performance was not affected by GHRH administration. Our findings indicate that intranasal GHRH, by counteracting endogenous GHRH release, impairs hippocampal memory processing. They provide first evidence for a critical contribution of central nervous somatotropic activity to hippocampus-dependent memory consolidation.

  20. Growth Hormone-Releasing Peptide 6 Enhances the Healing Process and Improves the Esthetic Outcome of the Wounds

    Directory of Open Access Journals (Sweden)

    Yssel Mendoza Marí

    2016-01-01

    Full Text Available In addition to its cytoprotective effects, growth hormone-releasing peptide 6 (GHRP-6 proved to reduce liver fibrotic induration. CD36 as one of the GHRP-6 receptors appears abundantly represented in cutaneous wounds granulation tissue. The healing response in a scenario of CD36 agonistic stimulation had not been previously investigated. Excisional full-thickness wounds (6 mmØ were created in the dorsum of Wistar rats and topically treated twice a day for 5 days. The universal model of rabbit’s ears hypertrophic scars was implemented and the animals were treated daily for 30 days. Treatments for both species were based on a CMC jelly composition containing GHRP-6 400 μg/mL. Wounds response characterization included closure dynamic, RT-PCR transcriptional profile, histology, and histomorphometric procedures. The rats experiment indicated that GHRP-6 pharmacodynamics involves attenuation of immunoinflammatory mediators, their effector cells, and the reduction of the expression of fibrotic cytokines. Importantly, in the hypertrophic scars rabbit’s model, GHRP-6 intervention dramatically reduced the onset of exuberant scars by activating PPARγ and reducing the expression of fibrogenic cytokines. GHRP-6 showed no effect on the reversion of consolidated lesions. This evidence supports the notion that CD36 is an active and pharmacologically approachable receptor to attenuate wound inflammation and accelerate its closure so as to improve wound esthetic.

  1. Menstruation recovery after chemotherapy and luteinizing hormone-releasing hormone agonist plus tamoxifen therapy for premenopausal patients with breast cancer.

    Science.gov (United States)

    Sakurai, Kenichi; Matsuo, Sadanori; Enomoto, Katsuhisa; Amano, Sadao; Shiono, Motomi

    2011-01-01

    Little is known about the period required for menstruation recovery after long-term luteinizing hormone-releasing hormone (LH-RH) agonist plus tamoxifen therapy following chemotherapy. In this study we investigated the period required for menstruation recovery after the therapy. The subjects comprised 105 premenopausal breast cancer patients who had undergone surgery. All patients were administered an LH-RH agonist for 24 months and tamoxifen for 5 years following the postoperative adjuvant chemotherapy, and the status of menstruation recovery was examined. Menstruation resumed in 16 cases (15.2%) after the last LH-RH agonist treatment session. The mean period from the last LH-RH agonist treatment to the recovery of menstruation was 6.9 months. The rate of menstruation recovery was 35.5% in patients aged 40 years or younger and 8.0% in those aged 41 years or older, and it was significantly higher in those aged 40 years or younger. The period until menstruation recovery tended to be longer in older patients at the end of treatment. This study showed that menstruation resumed after treatment at higher rates in younger patients. However, because it is highly likely that ovarian function will be destroyed by the treatment even in young patients, it is considered necessary to explain the risk to patients and obtain informed consent before introducing this treatment modality.

  2. Lack of stimulation of 24-hour growth hormone release by hypocaloric diet in obesity

    DEFF Research Database (Denmark)

    Rasmussen, M H; Juul, A; Kjems, L L

    1995-01-01

    Obesity is associated with a marked reduction in the spontaneous secretion of GH. To investigate the effect of acute alterations in calorie intake on GH release, 24-hr spontaneous GH release was measured during habitual calorie intake as well as during a short term, very low calorie diet (VLCD......) in 6 obese subjects, 5 obese subjects after weight loss, and 5 normal, age- and sex-matched control subjects. Integrated 20-min samples were obtained over 24-h on two occasions in each subject using a constant blood withdrawal technique. In addition, basal levels of serum insulin-like growth factor...... levels were elevated in obese subjects compared to those in normal age- and sex-matched controls. No differences between obese subjects and normal controls were present regarding IGF-I, IGFBP-3, or IGF-I/IGFBP-3 molar ratio. In the last 24 h during the 96-h VLCD, an increase in 24-h GH release and basal...

  3. Lack of stimulation of 24-hour growth hormone release by hypocaloric diet in obesity

    DEFF Research Database (Denmark)

    Rasmussen, M H; Juul, A; Kjems, L L

    1995-01-01

    ) in 6 obese subjects, 5 obese subjects after weight loss, and 5 normal, age- and sex-matched control subjects. Integrated 20-min samples were obtained over 24-h on two occasions in each subject using a constant blood withdrawal technique. In addition, basal levels of serum insulin-like growth factor...... levels were elevated in obese subjects compared to those in normal age- and sex-matched controls. No differences between obese subjects and normal controls were present regarding IGF-I, IGFBP-3, or IGF-I/IGFBP-3 molar ratio. In the last 24 h during the 96-h VLCD, an increase in 24-h GH release and basal....... This suggests a reversible defect in GH release, rather than a persistent preexisting disorder. It is hypothesized that enhanced bioavailability of IGF-I, acting in concert with elevated proinsulin and insulin levels, may account for the lack of stimulation of 24-hr GH release by the hypocaloric diet in obese...

  4. Somatostatin dramatically stimulates growth hormone release from primate somatotrophs acting at low doses via somatostatin receptor 5 and cyclic AMP.

    Science.gov (United States)

    Córdoba-Chacón, J; Gahete, M D; Culler, M D; Castaño, J P; Kineman, R D; Luque, R M

    2012-03-01

    Somatostatin and cortistatin have been shown to act directly on pituitary somatotrophs to inhibit growth hormone (GH) release. However, previous results from nonprimate species indicate that these peptides can also directly stimulate GH secretion, at low concentrations. The relevance of this phenomenon in a nonhuman primate model was investigated in the present study by testing the impact of somatostatin/cortistatin on GH release in primary pituitary cell cultures from baboons. High doses (> 10(-10) m) of somatostatin/cortistatin did not alter basal GH secretion but blocked GH-releasing hormone (GHRH)- and ghrelin-induced GH release. However, at low concentrations (10(-17)-10(-13) m), somatostatin/cortistatin dramatically stimulated GH release to levels comparable to those evoked by GHRH or ghrelin. Use of somatostatin receptor (sst) specific agonists/antagonists, and signal transduction blockers indicated that sst2 and sst1 activation via intact adenylate cylcase and mitogen-activated protein kinase systems mediated the inhibitory actions of high-concentration somatostatin. By contrast, the stimulatory actions of low-dose somatostatin on GH release were mediated by sst5 signalling through adenylate cylcase/cAMP/protein kinase A and intracellular Ca(2+) pathways, and were additive with ghrelin (not GHRH). Notably, low-concentrations of somatostatin, similar to sst5-agonists, inhibited prolactin release. These results clearly demonstrate that the ultimate impact of somatostatin/cortistatin on hormone release is dose-dependent, cell type-selective and receptor-specific, where the stimulatory effects of low-concentration somatostatin/cortistatin on GH release extend to primates, thereby supporting the notion that this action is relevant in regulating GH secretion in humans. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell Publishing Ltd.

  5. Neonatal imprinting predetermines the sexually dimorphic, estrogen-dependent expression of galanin in luteinizing hormone-releasing hormone neurons.

    Science.gov (United States)

    Merchenthaler, I; Lennard, D E; López, F J; Negro-Vilar, A

    1993-01-01

    The incidence of colocalization of galanin (GAL) in luteinizing hormone-releasing hormone (LHRH) neurons is 4- to 5-fold higher in female than male rats. This fact and the finding that the degree of colocalization parallels estradiol levels during the estrous cycle suggest that GAL is an estrogen-inducible product in a subset of LHRH neurons. To analyze further this paradigm we evaluated the effects of gonadectomy and steroid replacement therapy in male and female rats. Ovariectomy resulted in a significant decrease in the number of cells colocalizing LHRH and GAL, whereas estradiol replacement to such animals restored the incidence of colocalization to that observed in controls. In males, however, estradiol treatment failed to enhance the incidence of colocalization of GAL and LHRH, indicating, therefore, that the colocalization of these peptides is gender-determined. This possibility--i.e., gender-specific determination of LHRH neurons coexpressing GAL--was evaluated by neonatal manipulation of hypothalamic steroid imprinting. As mentioned above, male rats did not respond to estrogen or testosterone by increasing GAL/LHRH colocalization as females did. Neonatally orchidectomized rats, whose hypothalami have not been exposed to testosterone during the critical period, when treated with estrogen in adulthood showed an increase in colocalization of GAL and LHRH similar to that seen in female animals. These observations indicate that the colocalization of LHRH/GAL is neonatally determined by an epigenetic mechanism that involves the testis. In summary, this sex difference in the incidence of colocalization of GAL and LHRH represents a unique aspect of sexual differentiation in that only certain phenotypic characteristics of a certain cellular lineage are dimorphic. The subpopulation of LHRH neurons that also produces GAL represents a portion of the LHRH neuronal system that is sexually differentiated and programed to integrate, under steroidal control, a network of

  6. Deficiency of growth hormone-releasing hormone signaling is associated with sleep alterations in the dwarf rat.

    Science.gov (United States)

    Obál, F; Fang, J; Taishi, P; Kacsóh, B; Gardi, J; Krueger, J M

    2001-04-15

    The somatotropic axis, and particularly growth hormone-releasing hormone (GHRH), is implicated in the regulation of sleep-wake activity. To evaluate sleep in chronic somatotropic deficiency, sleep-wake activity was studied in dwarf (dw/dw) rats that are known to have a defective GHRH signaling mechanism in the pituitary and in normal Lewis rats, the parental strain of the dw/dw rats. In addition, expression of GHRH receptor (GHRH-R) mRNA in the hypothalamus/preoptic region and in the pituitary was also determined by means of reverse transcription-PCR, and GHRH content of the hypothalamus was measured. Hypothalamic/preoptic and pituitary GHRH-R mRNA levels were decreased in the dw/dw rats, indicating deficits in the central GHRHergic transmission. Hypothalamic GHRH content in dw/dw rats was also less than that found in Lewis rats. The dw/dw rats had less spontaneous nonrapid eye movement sleep (NREMS) (light and dark period) and rapid eye movement sleep (REMS) (light period) than did the control Lewis rats. After 4 hr of sleep deprivation, rebound increases in NREMS and REMS were normal in the dw/dw rat. As determined by fast Fourier analysis of the electroencephalogram (EEG), the sleep deprivation-induced enhancements in EEG slow-wave activity in the dw/dw rats were only one-half of the response in the Lewis rats. The results are compared with sleep findings previously obtained in GHRH-deficient transgenic mice. The alterations in NREMS are attributed to the defect in GHRH signaling, whereas the decreases in REMS might result from the growth hormone deficiency in the dw/dw rat.

  7. Synthetic Growth Hormone-Releasing Peptides (GHRPs: A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects

    Directory of Open Access Journals (Sweden)

    Jorge Berlanga-Acosta

    2017-02-01

    Full Text Available Background: Growth hormone-releasing peptides (GHRPs constitute a group of small synthetic peptides that stimulate the growth hormone secretion and the downstream axis activity. Mounting evidences since the early 1980s delineated unexpected pharmacological cardioprotective and cytoprotective properties for the GHRPs. However, despite intense basic pharmacological research, alternatives to prevent cell and tissue demise before lethal insults have remained as an empty niche in the clinical armamentarium. Here, we have rigorously reviewed the investigational development of GHRPs and their clinical niching perspectives. Methodology: PubMed/MEDLINE databases, including original research and review articles, were explored. The search design was date escalated from 1980 and included articles in English only. Results and Conclusions: GHRPs bind to two different receptors (GHS-R1a and CD36, which redundantly or independently exert relevant biological effects. GHRPs’ binding to CD36 activates prosurvival pathways such as PI-3K/AKT1, thus reducing cellular death. Furthermore, GHRPs decrease reactive oxygen species (ROS spillover, enhance the antioxidant defenses, and reduce inflammation. These cytoprotective abilities have been revealed in cardiac, neuronal, gastrointestinal, and hepatic cells, representing a comprehensive spectrum of protection of parenchymal organs. Antifibrotic effects have been attributed to some of the GHRPs by counteracting fibrogenic cytokines. In addition, GHRP family members have shown a potent myotropic effect by promoting anabolia and inhibiting catabolia. Finally, GHRPs exhibit a broad safety profile in preclinical and clinical settings. Despite these fragmented lines incite to envision multiple pharmacological uses for GHRPs, especially as a myocardial reperfusion damage-attenuating candidate, this family of “drugable” peptides awaits for a definitive clinical niche.

  8. Changes of growth hormone-releasing hormone and somatostatin neurons in the rat hypothalamus induced by genistein: a stereological study.

    Science.gov (United States)

    Trifunović, Svetlana; Manojlović-Stojanoski, Milica; Ristić, Nataša; Nestorović, Nataša; Medigović, Ivana; Živanović, Jasmina; Milošević, Verica

    2016-12-01

    Genistein is a plant-derived estrogenic isoflavone commonly found in dietary and therapeutic supplements, due to its potential health benefits. Growth hormone-releasing hormone (GHRH) and somatostatin (SS) are neurosecretory peptides synthesized in neurons of the hypothalamus and regulate the growth hormone secretion. Early reports indicate that estrogens have highly involved in the regulation of GHRH and SS secretions. Since little is known about the potential effects of genistein on GHRH and SS neurons, we exposed rats to genistein. Genistein were administered to adult rats in dose of 30 mg/kg, for 3 weeks. The estradiol-dipropionate treatment was used as the adequate controls to genistein. Using applied stereology on histological sections of hypothalamus, we obtained the quantitative information on arcuate (Arc) and periventricular (Pe) nucleus volume and volume density of GHRH neurons and SS neurons. Image analyses were used to obtain GHRH and SS contents in the median eminence (ME). Administration of estradiol-dipropionate caused the increase of Arc and Pe nucleus volume, SS neuron volume density, GHRH and SS staining intensity in the ME, when compared with control. Genistein treatment increased: Arc nucleus volume and the volume density of GHRH neurons (by 26%) and SS neurons (1.5 fold), accompanied by higher GHRH and SS staining intensity in the ME, when compared to the orhidectomized group. These results suggest that genistein has a significant effect on hypothalamic region, involved in the regulation of somatotropic system function, and could contribute to the understanding of genistein as substance that alter the hormonal balance.

  9. Novel activity of human angiotensin I converting enzyme: release of the NH2- and COOH-terminal tripeptides from the luteinizing hormone-releasing hormone.

    OpenAIRE

    Skidgel, R A; Erdös, E G

    1985-01-01

    Angiotensin I converting enzyme (ACE; kininase II; peptidyldipeptide hydrolase, EC 3.4.15.1) cleaves COOH-terminal dipeptides from active peptides containing a free COOH terminus. We investigated the hydrolysis of luteinizing hormone-releasing hormone (LH-RH) by homogeneous human ACE. Although this decapeptide is blocked at both the NH2 and COOH termini, it was metabolized to several peptides, which were separated by HPLC and identified by amino acid analysis. A major product was the NH2-term...

  10. Relative effectiveness of carp pituitary extract, luteinizing hormone releasing hormone analog LHRHa injections and LHRHa implants for producing hybrid catfish fry

    Science.gov (United States)

    Adoption of the hybrid catfish (channel catfish, Ictalruus punctatus, female x blue catfish, I. furcatus, male) is increasing in the catfish industry. The most effective way to produce fry is hormone induced spawning of females coupled with hand stripping and in vitro fertilization. The success of...

  11. Curcumin and synthetic analogs induce reactive oxygen species and decreases specificity protein (Sp transcription factors by targeting microRNAs

    Directory of Open Access Journals (Sweden)

    Gandhy Shruti U

    2012-11-01

    Full Text Available Abstract Background Curcumin inhibits growth of several cancer cell lines, and studies in this laboratory in bladder and pancreatic cancer cells show that curcumin downregulates specificity protein (Sp transcription factors Sp1, Sp3 and Sp4 and pro-oncogenic Sp-regulated genes. In this study, we investigated the anticancer activity of curcumin and several synthetic cyclohexanone and piperidine analogs in colon cancer cells. Methods The effects of curcumin and synthetic analogs on colon cancer cell proliferation and apoptosis were determined using standardized assays. The changes in Sp proteins and Sp-regulated gene products were analysed by western blots, and real time PCR was used to determine microRNA-27a (miR-27a, miR-20a, miR-17-5p and ZBTB10 and ZBTB4 mRNA expression. Results The IC50 (half-maximal values for growth inhibition (24 hr of colon cancer cells by curcumin and synthetic cyclohexanone and piperidine analogs of curcumin varied from 10 μM for curcumin to 0.7 μM for the most active synthetic piperidine analog RL197, which was used along with curcumin as model agents in this study. Curcumin and RL197 inhibited RKO and SW480 colon cancer cell growth and induced apoptosis, and this was accompanied by downregulation of specificity protein (Sp transcription factors Sp1, Sp3 and Sp4 and Sp-regulated genes including the epidermal growth factor receptor (EGFR, hepatocyte growth factor receptor (c-MET, survivin, bcl-2, cyclin D1 and NFκB (p65 and p50. Curcumin and RL197 also induced reactive oxygen species (ROS, and cotreatment with the antioxidant glutathione significantly attenuated curcumin- and RL197-induced growth inhibition and downregulation of Sp1, Sp3, Sp4 and Sp-regulated genes. The mechanism of curcumin-/RL197-induced repression of Sp transcription factors was ROS-dependent and due to induction of the Sp repressors ZBTB10 and ZBTB4 and downregulation of microRNAs (miR-27a, miR-20a and miR-17-5p that regulate these repressors

  12. Neither bST nor Growth Hormone Releasing Factor Alter Expression of Thyroid Hormone Receptors in Liver and Mammary Tissues

    Science.gov (United States)

    Physiological effects of thyroid hormones are mediated primarily by binding of triiodothyronine, to specific nuclear receptors. It has been hypothesized that organ-specific changes in production of triiodothyronine from its prohormone, thyroxine, target the action of thyroid hormones to the mammary...

  13. Luteinizing hormone responses to luteinizing hormone releasing hormone, and growth hormone and cortisol responses to insulin induced hypoglycaemia in functional secondary amenorrhoea.

    Science.gov (United States)

    Hirvonen, E; Seppälä, M; Karonen, S L; Adlercreutz, H

    1977-02-01

    Luteinizing hormone (LH) responses to luteinizing hormone releasing hormone (LHRH), and growth hormone (GH) and cortisol responses to insulin induced hypoglycaemia were studied in 56 women classified into 4 distinct groups of functional secondary amenorrhoea. The groups were: I, self-induced weight reduction (20 patients); II, post pill amenorrhoea (14 patients); III, anorexia nervosa (10 patients); and IV, idiopathic secondary amenorrhoea (12 patients). Only patients with no overlapping anamnestic factors were included. Group I patients had the most heavily impaired LHRH-LH responses, and the GH response to hypoglycaemia was smaller than in other groups. Cortisol responses were normal. Group II patients showed blunted LH responses and normal GH and cortisol responses. Group III patients showed normal or exaggerated LH responses in the recovery phase of anorexia nervosa, while those two patients who were in the static phase of the illness had impaired responses. GH responses varied greatly. Group IV patients had normal basal levels of LH and normal LH, GH and cortisol responses. The restoration of LH response is not solely correlated to body mass, since patients recovering from anorexia nervosa showed greater LHRH-LH responses with nutritional rehabilitation at 76% of ideal body weight than patients with self-induced weight reduction at 87% of ideal body weight. In idiopathic amenorrhoea the hypothalamic pituitary axis seems to be practically intact. The function of hypothalamic-pituitary axis may be impaired selectively in functional amenorrhoea. Corticotrophin releasing hormone function remains intact, and GH-response may be impaired or normal independently of the LH-response to LHRH. In self-induced weight reduction both functions were impaired. These tests are easily carried out with out-patients, and they give more information about the functional state of hypothalamic-pituitary axis than basal analyses of hypothalamic-pituitary axis than basal analyses of

  14. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2011-01-01

    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling...... is described. Results show that digital control can compete with the analog one in efficiency, PFC and THD....

  15. Analog Coding.

    Science.gov (United States)

    CODING, ANALOG SYSTEMS), INFORMATION THEORY, DATA TRANSMISSION SYSTEMS , TRANSMITTER RECEIVERS, WHITE NOISE, PROBABILITY, ERRORS, PROBABILITY DENSITY FUNCTIONS, DIFFERENTIAL EQUATIONS, SET THEORY, COMPUTER PROGRAMS

  16. Analog computing

    CERN Document Server

    Ulmann, Bernd

    2013-01-01

    This book is a comprehensive introduction to analog computing. As most textbooks about this powerful computing paradigm date back to the 1960s and 1970s, it fills a void and forges a bridge from the early days of analog computing to future applications. The idea of analog computing is not new. In fact, this computing paradigm is nearly forgotten, although it offers a path to both high-speed and low-power computing, which are in even more demand now than they were back in the heyday of electronic analog computers.

  17. In-vitro/in-vivo studies of the biodegradable poly-(D,L-lactide-co-glycolide) microspheres of a novel luteinizing hormone-releasing hormone antagonist for prostate cancer treatment.

    Science.gov (United States)

    Du, Lina; Mei, Xingguo; Wang, Chenyun; Li, Xin; Zhang, Fucheng; Jin, Yiguang

    2011-03-01

    The introduction of luteinizing hormone-releasing hormone (LHRH) analogs and their antagonists is revolutionizing the treatment of prostate cancer. In this study, poly(D,L-lactideco-glycolide) (PLGA) microspheres containing a highly potent LHRH antagonist (LXT-101) of interest in the indication of prostate cancer were evaluated on release mechanisms in vitro and biological performance in vivo. LXT-101 microspheres were prepared by the water/oil/water double emulsion method and the solid/oil/oil method. The results showed that the mechanism of LXT-101 releasing from PLGA 14,000 microspheres was the cooperation of drug diffusion and polymer degradation. This clarified the relationship between the microsphere characterization and hormone level in vivo. The larger microspheres (33 μm) could inhibit the testosterone level to castration for a longer time (35 days) than the smaller microspheres (15 μm, 14 days). The formulation containing the hydrophilic additive (polyethylene glycol 6000) could suppress the testosterone level to castration for a longer time (> 35 days) than the formulation without polyethylene glycol (14 days). The appearance of testis, vesicular seminalis, and prostates changed after treatment. The weights of sexual organs decreased significantly. The in-vivo release of the LXT-101 PLGA 14,000 microspheres curve showed that in-vivo release started immediately after day 1 (22.7%) and was rapid during the first 5 days (40.2% release). The LXT-101 microspheres could be a promising drug delivery system candidate to treat sex hormone-dependent tumors and other related disorders.

  18. Supplementation of oligofructose, but not sucralose, decreases high-fat diet induced body weight gain in mice independent of gustducin-mediated gut hormone release.

    Science.gov (United States)

    Steensels, Sandra; Cools, Leen; Avau, Bert; Vancleef, Laurien; Farré, Ricard; Verbeke, Kristin; Depoortere, Inge

    2017-03-01

    Enteroendocrine cells sense nutrients through taste receptors similar to those on the tongue. Sweet and fatty acid taste receptors (FFAR) coupled to the gustatory G-protein, gustducin, on enteroendocrine cells play a role in gut hormone release. We studied if supplementation of artificial (sucralose) or prebiotic (oligofructose; OFS) sweeteners target gustducin-mediated signaling pathways to alter gut hormone release and reduce obesity-associated disorders. Wild-type (WT) and α-gustducin knockout (α-gust -/- ) mice were fed a high-fat diet and gavaged once daily (8 wk) with water or equisweet concentrations of sweeteners. OFS but not sucralose decreased body weight gain (-19 ± 3%, p sucralose, reduced body weight gain and decreased intestinal permeability, but not glucose intolerance. Effects were not mediated by altered gut hormone levels or gustducin-mediated signaling. Artificial sweeteners do not affect gut hormone levels and are metabolically inert in mice on a high-fat diet. In contrast, prebiotic oligosaccharides (OFS) prevent body weight gain but not glucose intolerance. Alterations in sweet and short-chain fatty acid receptors (FFAR) (studied in WT and α-gust -/- mice) that regulate gut hormone levels are not mandatory for the positive effects of OFS. Enhanced uptake of SCFAs may favor interaction with FFAR2/3 on adipose tissue to induce weight loss. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Tissue factor pathway inhibitor prevents airway obstruction, respiratory failure and death due to sulfur mustard analog inhalation.

    Science.gov (United States)

    Rancourt, Raymond C; Veress, Livia A; Ahmad, Aftab; Hendry-Hofer, Tara B; Rioux, Jacqueline S; Garlick, Rhonda B; White, Carl W

    2013-10-01

    Sulfur mustard (SM) inhalation causes airway injury, with enhanced vascular permeability, coagulation, and airway obstruction. The objective of this study was to determine whether recombinant tissue factor pathway inhibitor (TFPI) could inhibit this pathogenic sequence. Rats were exposed to the SM analog 2-chloroethyl ethyl sulfide (CEES) via nose-only aerosol inhalation. One hour later, TFPI (1.5mg/kg) in vehicle, or vehicle alone, was instilled into the trachea. Arterial O2 saturation was monitored using pulse oximetry. Twelve hours after exposure, animals were euthanized and bronchoalveolar lavage fluid (BALF) and plasma were analyzed for prothrombin, thrombin-antithrombin complex (TAT), active plasminogen activator inhibitor-1 (PAI-1) levels, and fluid fibrinolytic capacity. Lung steady-state PAI-1 mRNA was measured by RT-PCR analysis. Airway-capillary leak was estimated by BALF protein and IgM, and by pleural fluid measurement. In additional animals, airway cast formation was assessed by microdissection and immunohistochemical detection of airway fibrin. Airway obstruction in the form of fibrin-containing casts was evident in central conducting airways of rats receiving CEES. TFPI decreased cast formation, and limited severe hypoxemia. Findings of reduced prothrombin consumption, and lower TAT complexes in BALF, demonstrated that TFPI acted to limit thrombin activation in airways. TFPI, however, did not appreciably affect CEES-induced airway protein leak, PAI-1 mRNA induction, or inhibition of the fibrinolytic activity present in airway surface liquid. Intratracheal administration of TFPI limits airway obstruction, improves gas exchange, and prevents mortality in rats with sulfur mustard-analog-induced acute lung injury. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Tissue factor pathway inhibitor prevents airway obstruction, respiratory failure and death due to sulfur mustard analog inhalation

    Energy Technology Data Exchange (ETDEWEB)

    Rancourt, Raymond C., E-mail: raymond.rancourt@ucdenver.edu; Veress, Livia A., E-mail: livia.veress@ucdenver.edu; Ahmad, Aftab, E-mail: aftab.ahmad@ucdenver.edu; Hendry-Hofer, Tara B., E-mail: tara.hendry-hofer@ucdenver.edu; Rioux, Jacqueline S., E-mail: jacqueline.rioux@ucdenver.edu; Garlick, Rhonda B., E-mail: rhonda.garlick@ucdenver.edu; White, Carl W., E-mail: carl.w.white@ucdenver.edu

    2013-10-01

    Sulfur mustard (SM) inhalation causes airway injury, with enhanced vascular permeability, coagulation, and airway obstruction. The objective of this study was to determine whether recombinant tissue factor pathway inhibitor (TFPI) could inhibit this pathogenic sequence. Methods: Rats were exposed to the SM analog 2-chloroethyl ethyl sulfide (CEES) via nose-only aerosol inhalation. One hour later, TFPI (1.5 mg/kg) in vehicle, or vehicle alone, was instilled into the trachea. Arterial O{sub 2} saturation was monitored using pulse oximetry. Twelve hours after exposure, animals were euthanized and bronchoalveolar lavage fluid (BALF) and plasma were analyzed for prothrombin, thrombin–antithrombin complex (TAT), active plasminogen activator inhibitor-1 (PAI-1) levels, and fluid fibrinolytic capacity. Lung steady-state PAI-1 mRNA was measured by RT-PCR analysis. Airway-capillary leak was estimated by BALF protein and IgM, and by pleural fluid measurement. In additional animals, airway cast formation was assessed by microdissection and immunohistochemical detection of airway fibrin. Results: Airway obstruction in the form of fibrin-containing casts was evident in central conducting airways of rats receiving CEES. TFPI decreased cast formation, and limited severe hypoxemia. Findings of reduced prothrombin consumption, and lower TAT complexes in BALF, demonstrated that TFPI acted to limit thrombin activation in airways. TFPI, however, did not appreciably affect CEES-induced airway protein leak, PAI-1 mRNA induction, or inhibition of the fibrinolytic activity present in airway surface liquid. Conclusions: Intratracheal administration of TFPI limits airway obstruction, improves gas exchange, and prevents mortality in rats with sulfur mustard-analog-induced acute lung injury. - Highlights: • TFPI administration to rats after mustard inhalation reduces airway cast formation. • Inhibition of thrombin activation is the likely mechanism for limiting casts. • Rats given TFPI

  1. Anticancer effects of novel thalidomide analogs in A549 cells through inhibition of vascular endothelial growth factor and matrix metalloproteinase-2.

    Science.gov (United States)

    El-Aarag, Bishoy; Kasai, Tomonari; Masuda, Junko; Agwa, Hussein; Zahran, Magdy; Seno, Masaharu

    2017-01-01

    Lung cancer is one of the major causes of cancer-related mortality worldwide, and non-small-cell lung cancer is the most common form of lung cancer. Several studies had shown that thalidomide has potential for prevention and therapy of cancer. Therefore, the current study aimed to investigate the antitumor effects of two novel thalidomide analogs in human lung cancer A549 cells. The antiproliferative, antimigratory, and apoptotic effects in A549 cells induced by thalidomide analogs were examined. In addition, their effects on the expression of mRNAs encoding vascular endothelial growth factor165 (VEGF165) and matrix metalloproteinase-2 (MMP-2) were evaluated. Their influence on the tumor volume in nude mice was also determined. Results revealed that thalidomide analogs exhibited antiproliferative, antimigratory, and apoptotic activities with more pronounced effect than thalidomide drug. Furthermore, analogs 1 and 2 suppressed the expression levels of VEGF165 by 42% and 53.2% and those of MMP-2 by 45% and 52%, respectively. Thalidomide analogs 1 and 2 also reduced the tumor volume by 30.11% and 53.52%, respectively. Therefore, this study provides evidence that thalidomide analogs may serve as a new therapeutic option for treating lung cancer. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Treatment of endometriosis with a delayed release preparation of the agonist D-Trp6-luteinizing hormone-releasing hormone: long-term follow-up in a series of 50 patients.

    Science.gov (United States)

    Zorn, J R; Mathieson, J; Risquez, F; Comaru-Schally, A M; Schally, A V

    1990-03-01

    Fifty patients with proven endometriosis were treated for 6 to 9 months with a delayed release preparation of microcapsules of the luteinizing hormone-releasing hormone (LH-RH) agonist D-Trp6-LH-RH, injected intramuscularly at monthly intervals. After a transitory ovarian stimulation at the onset of treatment, serum estradiol was suppressed to menopausal levels (50 pg/mL). This state of hypogonadism was reversible after the discontinuation of treatment, and menses resumed within 4 months after the last injection. Pelvic pain was relieved during treatment in 87.5% of patients. After a follow-up period of up to 37 months, 24 patients are in clinical remission and 9 experienced recurrence of endometriosis 7 to 14 months after completing treatment. One patient failed to respond to therapy with the agonist and 7 patients were lost to follow-up. Among 16 previously infertile patients with no other factors contributing to infertility, 7 became pregnant; 2 of these pregnancies were the result of gamete intrafallopian transfers. An eighth patient without documented infertility also conceived spontaneously. Side effects due to hypoestrogenism were reported by nearly all patients. In conclusion, D-Trp6-LH-RH microcapsules are effective and easily-administered agents for the treatment of endometriosis.

  3. Airway tissue factor-dependent coagulation activity in response to sulfur mustard analog 2-chloroethyl ethyl sulfide.

    Science.gov (United States)

    Rancourt, Raymond C; Veress, Livia A; Guo, Xiaoling; Jones, Tara N; Hendry-Hofer, Tara B; White, Carl W

    2012-01-01

    Acute lung injury is a principal cause of morbidity and mortality in response to mustard gas (SM) inhalation. Obstructive, fibrin-containing airway casts have recently been reported in a rat inhalation model employing the SM analog 2-chloroethyl ethyl sulfide (CEES). The present study was designed to identify the mechanism(s) causing activation of the coagulation cascade after CEES-induced airway injury. Here we report that CEES inhalation elevates tissue factor (TF) activity and numbers of detached epithelial cells present in lavage fluid (BALF) from rats after exposure (18 h). In vitro studies using 16HBE cells, or with rat BALF, indicated that detached epithelial cells could convert factor X (FX) to the active form FXa when incubated with factor VII and could elicit rapid clotting of plasma. In addition, immunocytochemical analysis demonstrated elevated cell surface (TF) expression on CEES-exposed 16HBE cells as a function of time. However, total cell TF expression did not increase. Since membrane surfaces bearing TF are important determinants of clot initiation, anticoagulants directed against these entities were tested for ability to limit plasma clotting or FX activation capacity of BALF or culture media. Addition of tifacogin, a TF pathway inhibitor, effectively blocked either activity, demonstrating that the procoagulant actions of CEES were TF pathway dependent. Lactadherin, a protein capable of competing with clotting factors for phospholipid-binding sites, was partially effective in limiting these procoagulant actions. These findings indicate that TF pathway inhibition could be an effective strategy to prevent airway obstruction after SM or CEES inhalation.

  4. Cyclic peptide analogs of 558-565 epitope of A2 subunit of Factor VIII prolong aPTT. Toward a novel synthesis of anticoagulants.

    Science.gov (United States)

    Anastasopoulos, C; Sarigiannis, Y; Stavropoulos, G

    2014-04-01

    Novel anticoagulant therapies target specific clotting factors in blood coagulation cascade. Inhibition of the blood coagulation through Factor VIII-Factor IX interaction represents an attractive approach for the treatment and prevention of diseases caused by thrombosis. Our research efforts are continued by the synthesis and biological evaluation of cyclic, head to tail peptides, analogs of the 558-565 sequence of the A2 subunit of FVIII, aiming at the efficient inhibition of Factor VIIIa-Factor IXa interaction. The analogs were synthesized on solid phase using the acid labile 2-chlorotrityl chloride resin, while their anticoagulant activities were examined in vitro by monitoring activated partial thromboplastin time and the inhibition of Factor VIII activity. The results reveal that these peptides provide bases for the development of new anticoagulant agents.

  5. Changes in growth hormone-binding protein in girls with central precocious puberty treated with a depot preparation of luteinizing hormone-releasing hormone analogue.

    Science.gov (United States)

    Oliveira, S B; Donnadieu, M; Chaussain, J L

    1993-01-01

    Growth hormone-binding protein (GHBP) was studied in 11 girls with true precocious puberty, aged 7.3 +/- 0.2 years (mean +/- SE), before and after the first 6 months of treatment with luteinizing hormone-releasing hormone analogue D-Trp6-LHRH. The 125I-human GH was incubated with 150 microliters of serum, bound and free GH were separated by gel filtration. The levels of GHBP increased significantly from 24.2 +/- 1.3 to 28.1 +/- 1.9% (p pubertal spurt is mediated by a sex-steroid-induced rise in GH concentration, and they suggest that the levels of GHBP may be related to the GH secretion and its variation with treatment.

  6. Activity ranking of synthetic analogs targeting vascular endothelial growth factor receptor 2 by an integrated cell membrane chromatography system.

    Science.gov (United States)

    Wang, Dongyao; Lv, Diya; Chen, Xiaofei; Liu, Yue; Ding, Xuan; Jia, Dan; Chen, Langdong; Zhu, Zhenyu; Cao, Yan; Chai, Yifeng

    2015-12-01

    Evaluating the biological activities of small molecules represents an important part of the drug discovery process. Cell membrane chromatography (CMC) is a well-developed biological chromatographic technique. In this study, we have developed combined SMMC-7721/CMC and HepG2/CMC with high-performance liquid chromatography and time-of-flight mass spectrometry to establish an integrated screening platform. These systems was subsequently validated and used for evaluating the activity of quinazoline compounds, which were designed and synthesized to target vascular endothelial growth factor receptor 2. The inhibitory activities of these compounds towards this receptor were also tested using a classical caliper mobility shift assay. The results revealed a significant correlation between these two methods (R(2) = 0.9565 or 0.9420) for evaluating the activities of these compounds. Compared with traditional methods of evaluating the activities analogous compounds, this integrated cell membrane chromatography screening system took less time and was more cost effective, indicating that it could be used as a practical method in drug discovery. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Analog earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, R.B. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    Analogs are used to understand complex or poorly understood phenomena for which little data may be available at the actual repository site. Earthquakes are complex phenomena, and they can have a large number of effects on the natural system, as well as on engineered structures. Instrumental data close to the source of large earthquakes are rarely obtained. The rare events for which measurements are available may be used, with modfications, as analogs for potential large earthquakes at sites where no earthquake data are available. In the following, several examples of nuclear reactor and liquified natural gas facility siting are discussed. A potential use of analog earthquakes is proposed for a high-level nuclear waste (HLW) repository.

  8. Treatment of Paraphilic Disorders in Sexual Offenders or Men With a Risk of Sexual Offending With Luteinizing Hormone-Releasing Hormone Agonists: An Updated Systematic Review.

    Science.gov (United States)

    Turner, Daniel; Briken, Peer

    2018-01-01

    Different pharmacologic agents are used in the treatment of paraphilic disorders in sexual offenders or men with a risk of sexual offending, with luteinizing hormone-releasing hormone (LHRH) agonists being the agents introduced more recently to treatment regimens. To summarize the relevant literature concerning LHRH agonist treatment of paraphilic disorders in sexual offenders and update the previously published systematic review by Briken et al (J Clin Psychiatry 2003;64:890-897). The PubMed and Google Scholar databases were searched for literature published from January 2003 through October 2017 using the following key words: LHRH agonists, GnRH agonists, antiandrogens AND paraphilia, pedophilia, sex offenders. Evaluation of the effectiveness and side effects of LHRH agonist treatment of paraphilic disorders in sexual offenders. After screening for duplicates and applying specific selection criteria, the search yielded 24 eligible studies reporting on a sample of 256 patients. There is increasing evidence that LHRH agonists are more effective than steroidal antiandrogens in lowering paraphilic sexual thoughts and behaviors. Current research also is based on methods that might be less susceptible to faking (eg, eye-tracking, brain imaging, and viewing-time measures). Side effects occurring most frequently are fatigue, hot flashes, depressive mood, weight gain, high blood pressure, diabetes, gynecomastia, loss of erectile function, and loss of bone mineral density. Although LHRH agonists seem to be the most effective drugs in the treatment of paraphilic fantasies and behaviors, they should be reserved for patients with a paraphilic disorder and the highest risk of sexual offending because of their extensive side effects. This systematic review considers all types of research on LHRH agonist treatment in patients with paraphilic disorders, thereby providing a complete overview of the current state of research. However, most studies are case reports or observational

  9. Pralmorelin: GHRP 2, GPA 748, growth hormone-releasing peptide 2, KP-102 D, KP-102 LN, KP-102D, KP-102LN.

    Science.gov (United States)

    2004-01-01

    Pralmorelin [GPA 748, GHRP 2, growth hormone-releasing peptide 2, KP-102 D, KP 102 LN] is an orally active, synthetic growth hormone-releasing peptide from a series of compounds that were developed by Polygen in Germany and Tulane University in the US. Researchers at Tulane University led by Dr Cyril Bowers synthesised a series of small highly active peptides ranging in size from 3-5 amino acids or partial peptides that were suitable for a variety of administration formats (subcutaneous, buccal, oral, depot). These peptides mimic the actions of ghrelin, a 28 amino acid octanoyl peptide that regulates the release of growth hormone (GH), and may play an important role in bone and muscle growth, food intake and possibly improve recovery from injury. The use of pralmorelin as a diagnostic agent for GH deficiency is based on its ability to markedly increase plasma levels of GH in healthy subjects irrespectively of gender, obesity or age. However, in patients with GH deficiency, the effect of pralmorelin on GH levels is significantly lower compared with healthy controls. Analysis of the receiver-operating characteristics curve provided the cut-off threshold value for the GH peak of 15.0 micro g/L for the identification of patients with GH deficiency from those of healthy controls. Kaken acquired worldwide manufacturing and marketing rights to pralmorelin, and then sublicensed it to Wyeth (formerly American Home Products) for the US and Canada. Kaken retains rights to pralmorelin in Japan. On 11 March 2002 American Home Products changed its name and the names of its subsidiaries Wyeth-Ayerst and Wyeth Lederle to Wyeth. Kaken also granted exclusive sublicense options in Africa, Australia, Europe, Latin America and New Zealand to unspecified partners. Pralmorelin as KP-102 D [KP-102D] is currently awaiting approval in Japan as a diagnostic agent for hypothalamo-pituitary function. It is planned to be launched in Japan for this indication in 2004. Pralmorelin is also

  10. A 66-kDa protein of bovine hypophyseal Pars tuberalis induces luteinizing hormone release from rat Pars distalis.

    Science.gov (United States)

    Lafarque, Martha; Oliveros, Liliana

    2008-12-01

    In this study, evidence for a factor secreted by bovine hypophyseal pars tuberalis that stimulates luteinizing hormone (LH) release from rat pars distalis cells is shown. The secretion products of bovine pars tuberalis cells into the culture medium were assayed on dispersed rat pars distalis cells in 30 min incubations and superfusion experiments. The culture medium from pars tuberalis total cell populations, added at a dose of 6 microg per tube, induced the greater LH release from pars distalis cells, without effect on follicle stimulating hormone (FSH) release. After pars tuberalis cells separation on a discontinuos Percoll gradient, only the culture medium of cells from 50 and 60% strength Percoll were able to release LH from rat pars distalis cells. Therefore, cell fractions from 50 and 60% strenght Percoll were cultured together. To elicit maximal LH release (6 times the basal output), with the addition of 2 microg of pars tuberalis protein was required, suggesting that these cells produce the factor or factors which affect pars distalis gonadotrope cells. After applying the pars tuberalis culture medium on 12% SDS-PAGE, the band with biological activity was that of 66-kDal. Fifty ng protein of its eluate released almost 9 times the basal output of LH from pars distalis cells. Results suggest a modulating effect of a protein from the bovine pars tuberalis on rat cultured gonadotrope cells from the pars distalis.

  11. Investigation of the clinical significance of the growth hormone-releasing peptide-2 test for the diagnosis of secondary adrenal failure.

    Science.gov (United States)

    Arimura, Hiroshi; Hashiguchi, Hiroshi; Yamamoto, Kiyoaki; Shinnakasu, Atsushi; Arimura, Aiko; Kikuchi, Akira; Deguchi, Takahisa; Habu, Mika; Fujio, Singo; Arita, Kazunori; Nishio, Yoshihiko

    2016-06-30

    The aim of this study was to evaluate the ability of the growth hormone-releasing peptide-2 (GHRP-2) test to clinically diagnose hypothalamo-pituitary-adrenal (HPA) axis failure. We performed an insulin tolerance test (ITT), CRH stimulation test, and GHRP-2 test on 47 patients suspected of having a hypothalamo-pituitary disorder. Patients with pituitary disorders had significantly lower ACTH responses to the GHRP-2 test compared to patients with hypothalamic disorders and the control group. In contrast, peak cortisol levels in response to the GHRP-2 test were significantly lower in both hypothalamic and pituitary disorder cases compared with the control group. Assignment of a cut-off value of 11.6 μg/dL for the peak serum cortisol level demonstrated that the GHRP-2 test was able to predict secondary hypoadrenalism with 88.9% specificity and 89.7% sensitivity. The responses of ACTH and cortisol to the GHRP-2 test had no correlation to the CRH test, suggesting the involvement of a different mechanism of ACTH secretion. These results indicate that the GHRP-2 test may induce ACTH secretion from the pituitary gland through direct stimulation. Although the GHRP-2 test does not have the same predictive value as the insulin tolerance test (ITT), it has similar diagnostic potential as the CRH stimulation test for evaluating HPA axis failure.

  12. SIRT1 Regulates Thyroid-Stimulating Hormone Release by Enhancing PIP5Kgamma Activity through Deacetylation of Specific Lysine Residues in Mammals.

    Directory of Open Access Journals (Sweden)

    Sayaka Akieda-Asai

    Full Text Available BACKGROUND: SIRT1, a NAD-dependent deacetylase, has diverse roles in a variety of organs such as regulation of endocrine function and metabolism. However, it remains to be addressed how it regulates hormone release there. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that SIRT1 is abundantly expressed in pituitary thyrotropes and regulates thyroid hormone secretion. Manipulation of SIRT1 level revealed that SIRT1 positively regulated the exocytosis of TSH-containing granules. Using LC/MS-based interactomics, phosphatidylinositol-4-phosphate 5-kinase (PIP5Kgamma was identified as a SIRT1 binding partner and deacetylation substrate. SIRT1 deacetylated two specific lysine residues (K265/K268 in PIP5Kgamma and enhanced PIP5Kgamma enzyme activity. SIRT1-mediated TSH secretion was abolished by PIP5Kgamma knockdown. SIRT1 knockdown decreased the levels of deacetylated PIP5Kgamma, PI(4,5P(2, and reduced the secretion of TSH from pituitary cells. These results were also observed in SIRT1-knockout mice. CONCLUSIONS/SIGNIFICANCE: Our findings indicated that the control of TSH release by the SIRT1-PIP5Kgamma pathway is important for regulating the metabolism of the whole body.

  13. Growth hormone-releasing hormone antagonist inhibits the invasiveness of human endometrial cancer cells by down-regulating twist and N-cadherin expression.

    Science.gov (United States)

    Wu, Hsien-Ming; Huang, Hong-Yuan; Schally, Andrew V; Chao, Angel; Chou, Hung-Hsueh; Leung, Peter C K; Wang, Hsin-Shih

    2017-01-17

    More than 25% of patients diagnosed with endometrial carcinoma have invasive primary cancer accompanied by metastases. Growth hormone-releasing hormone (GHRH) plays an important role in reproduction. Here, we examined the effect of a GHRH antagonist on the motility of endometrial cancer cells and the mechanisms of action of the antagonist in endometrial cancer. Western blotting and immunohistochemistry (IHC) were used to determine the expression of the GHRH receptor protein. The activity of Twist and N-cadherin was determined by Western blotting. Cell motility was assessed by an invasion and migration assay. GHRH receptor siRNA was applied to knockdown the GHRH receptor in endometrial cancer cells. The GHRH antagonist inhibited cell motility in a dose-dependent manner. The GHRH antagonist inhibited cell motility and suppressed the expression of Twist and N-cadherin, and the suppression was abolished by GHRH receptor siRNA pretreatment. Moreover, the inhibition of Twist and N-cadherin with Twist siRNA and N-cadherin siRNA, respectively, suppressed cell motility. Our study indicates that the GHRH antagonist inhibited the cell motility of endometrial cancer cells through the GHRH receptor via the suppression of Twist and N-cadherin. Our findings represent a new concept in the mechanism of GHRH antagonist-suppressed cell motility in endometrial cancer cells and suggest the possibility of exploring GHRH antagonists as potential therapeutics for the treatment of human endometrial cancer.

  14. Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release.

    Directory of Open Access Journals (Sweden)

    Nora Prochnow

    Full Text Available Harmful effects of electromagnetic fields (EMF on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF signals of the Universal Mobile Telecommunications System (UMTS to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH and on hippocampal derived synaptic long-term plasticity (LTP and depression (LTD as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg. The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg cannot be excluded.

  15. Intragastric infusion of the bitter tastant quinine suppresses hormone release and antral motility during the fasting state in healthy female volunteers.

    Science.gov (United States)

    Deloose, E; Corsetti, M; Van Oudenhove, L; Depoortere, I; Tack, J

    2018-01-01

    Intragastric administration of the bitter tastant denatonium benzoate inhibits the increase of motilin plasma levels and antral contractility. While these findings suggest that gastrointestinal bitter taste receptors could be new targets to modulate gastrointestinal motility and hormone release, they need confirmation with other bitter receptor agonists. The primary aim was to evaluate the effect of intragastric administration of the bitter tastant quinine-hydrochloride (QHCl) on motilin and ghrelin plasma levels. Secondly, we studied the effect on interdigestive motility. Ten healthy female volunteers were recruited (33±4 y; 22±0.5 kg/m²). Placebo or QHCl (10 μmol/kg) was administered intragastrically through a nasogastric feeding tube after an overnight fast in a single-blind randomized fashion. Administration started 20 min after the first phase III of the migrating motor complex. The measurement continued for another 2 h after the administration. Blood samples were collected every 10 min with the baseline sample taken 10 min prior to administration. The increase in plasma levels of motilin (administration; P=.04) and total ghrelin (administration; P=.02) was significantly lower after QHCl. The fluctuation of octanoylated ghrelin was reduced after QHCl (time by administration; P=.03). Duodenal motility did not differ. The fluctuation of antral activity differed over time between placebo and QHCl (time by administration; P=.03). QHCl suppresses the increase of both motilin and ghrelin plasma levels. Moreover, QHCl reduced the fluctuation of antral motility. These findings confirm the potential of bitter taste receptors as targets for modifying interdigestive motility in man. © 2017 John Wiley & Sons Ltd.

  16. Ovarian suppression using luteinizing hormone-releasing hormone agonists during chemotherapy to preserve ovarian function and fertility of breast cancer patients: a meta-analysis of randomized studies.

    Science.gov (United States)

    Lambertini, M; Ceppi, M; Poggio, F; Peccatori, F A; Azim, H A; Ugolini, D; Pronzato, P; Loibl, S; Moore, H C F; Partridge, A H; Bruzzi, P; Del Mastro, L

    2015-12-01

    The role of temporary ovarian suppression with luteinizing hormone-releasing hormone agonists (LHRHa) in the prevention of chemotherapy-induced premature ovarian failure (POF) is still controversial. Our meta-analysis of randomized, controlled trials (RCTs) investigates whether the use of LHRHa during chemotherapy in premenopausal breast cancer patients reduces treatment-related POF rate, increases pregnancy rate, and impacts disease-free survival (DFS). A literature search using PubMed, Embase, and the Cochrane Library, and the proceedings of major conferences, was conducted up to 30 April 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) for POF (i.e. POF by study definition, and POF defined as amenorrhea 1 year after chemotherapy completion) and for patients with pregnancy, as well hazard ratios (HRs) and 95% CI for DFS, were calculated for each trial. Pooled analysis was carried out using the fixed- and random-effects models. A total of 12 RCTs were eligible including 1231 breast cancer patients. The use of LHRHa was associated with a significant reduced risk of POF (OR 0.36, 95% CI 0.23-0.57; P chemotherapy completion, the addition of LHRHa reduced the risk of POF (OR 0.55, 95% CI 0.41-0.73, P chemotherapy-induced POF and seems to increase the pregnancy rate, without an apparent negative consequence on prognosis. © The Author 2015. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  17. Diagnostic challenges and management of a patient with acromegaly due to ectopic growth hormone-releasing hormone secretion from a bronchial carcinoid tumour

    Directory of Open Access Journals (Sweden)

    Nikolaos Kyriakakis

    2017-01-01

    Full Text Available A male patient presented at the age of 30 with classic clinical features of acromegaly and was found to have elevated growth hormone levels, not suppressing during an oral glucose tolerance test. His acromegaly was originally considered to be of pituitary origin, based on a CT scan, which was interpreted as showing a pituitary macroadenoma. Despite two trans-sphenoidal surgeries, cranial radiotherapy and periods of treatment with bromocriptine and octreotide, his acromegaly remained active clinically and biochemically. A lung mass was discovered incidentally on a chest X-ray performed as part of a routine pre-assessment for spinal surgery 5 years following the initial presentation. This was confirmed to be a bronchial carcinoid tumour, which was strongly positive for growth hormone-releasing hormone (GHRH and somatostatin receptor type 2 by immunohistochemistry. The re-examination of the pituitary specimens asserted the diagnosis of pituitary GH hyperplasia. Complete resolution of the patient’s acromegaly was achieved following right lower and middle lobectomy. Seventeen years following the successful resection of the bronchial carcinoid tumour the patient remains under annual endocrine follow-up for monitoring of the hypopituitarism he developed after the original interventions to his pituitary gland, while there has been no evidence of active acromegaly or recurrence of the carcinoid tumour. Ectopic acromegaly is extremely rare, accounting for <1% of all cases of acromegaly. Our case highlights the diagnostic challenges differentiating between ectopic acromegaly and acromegaly of pituitary origin and emphasises the importance of avoiding unnecessary pituitary surgery and radiotherapy. The role of laboratory investigations, imaging and histology as diagnostic tools is discussed.

  18. Electromagnetic Field Effect or Simply Stress? Effects of UMTS Exposure on Hippocampal Longterm Plasticity in the Context of Procedure Related Hormone Release

    Science.gov (United States)

    Ladage, Kerstin; Krause-Finkeldey, Dorothee; El Ouardi, Abdessamad; Bitz, Andreas; Streckert, Joachim; Hansen, Volkert; Dermietzel, Rolf

    2011-01-01

    Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded. PMID:21573218

  19. Prior administration of a non-steroidal anti-androgen failed to prevent the flare-up caused by a luteinizing hormone-releasing hormone agonist in a patient with metastatic prostate cancer.

    Science.gov (United States)

    Uehara, Sho; Yuasa, Takeshi; Fujii, Yasuhisa; Yano, Akihiro; Yamamoto, Shinya; Masuda, Hitoshi; Fukui, Iwao; Yonese, Junji

    2015-08-05

    'Flare phenomenon' after initial luteinizing hormone-releasing hormone agonist administration is a widely approved concept in the treatment of prostate cancer. In most guidelines, concomitant therapy with anti-androgens is recommended to prevent this flare phenomenon. However, there are few reports describing serum prostate-specific antigen transitions after hormonal therapy. Here, we present a case of a man who experienced the biochemical and clinical flare phenomenon despite prior anti-androgen use and who has detailed data. A 70-year-old Asian man with metastatic prostate cancer (multiple bone) was referred to our hospital. He was treated with prior anti-androgens and luteinizing hormone-releasing hormone agonist. Regardless of prior use of anti-androgens, his low back pain caused by bone metastases was deteriorated and serum prostate-specific antigen level was raised from 974.8 ng/mL to 2,555.5 ng/mL within 3 weeks. Then, his serum prostate specific antigen level started to decrease along with the pain. The nadir reached 1.0 ng/mL and remained for 6 months. Because the serum level of prostate-specific antigen then began to increase again, anti-androgen was discontinued for anti-androgen withdrawal syndrome. Then the serum level decreased again to less than 0.1 ng/mL. Until now, his serum prostate-specific antigen level has been maintained at less than 0.1 ng/mL for more than 30 months without any clinical progressions. We present the case of a patient in whom a clinical flare caused by an leuteinizing hormone-releasing hormone agonist was not prevented by prior anti-androgen administration. In addition, the nadir level of prostate-specific antigen when he received leuteinizing hormone-releasing hormone monotherapy was ten times lower than when he received concomitant therapy, and period of anti-androgen withdrawal syndrome was longer than usual. In this case, anti-androgen was probably not effective from the initial administration. Awareness of the possibility

  20. Effect of priming injections of luteinizing hormone-releasing hormone on spermiation and ovulation in Gϋnther's Toadlet, Pseudophryne guentheri

    Directory of Open Access Journals (Sweden)

    Silla Aimee J

    2011-05-01

    Full Text Available Abstract Background In the majority of vertebrates, gametogenesis and gamete-release depend on the pulsatile secretion of luteinizing hormone-releasing hormone (LHRH from the hypothalamus. Studies attempting to artificially stimulate ovulation and spermiation may benefit from mimicking the naturally episodic secretion of LHRH by administering priming injections of a synthetic analogue (LHRHa. This study investigated the impact of low-dose priming injections of LHRHa on gamete-release in the Australian toadlet Pseudophryne guentheri. Methods Toadlets were administered a single dose of two micrograms per. gram LHRHa without a priming injection (no priming, or preceded by one (one priming or two (two priming injections of 0.4 micrograms per. gram LHRHa. Spermiation responses were evaluated at 3, 7 and 12 hrs post hormone administration (PA, and sperm number and viability were quantified using fluorescent microscopy. Oocyte yields were evaluated by stripping females at 10-11 hrs PA. A sub-sample of twenty eggs per female was then fertilised (with sperm obtained from testis macerates and fertilisation success determined. Results No priming induced the release of the highest number of spermatozoa, with a step-wise decrease in the number of spermatozoa released in the one and two priming treatments respectively. Peak sperm-release occurred at 12 hrs PA for all priming treatments and there was no significant difference in sperm viability. Females in the control treatment failed to release oocytes, while those administered an ovulatory dose without priming exhibited a poor ovulatory response. The remaining two priming treatments (one and two priming successfully induced 100% of females to expel an entire clutch. Oocytes obtained from the no, or two priming treatments all failed to fertilise, however oocytes obtained from the one priming treatment displayed an average fertilisation success of 97%. Conclusion Spermiation was most effectively induced in

  1. Insulin-like Growth Factor 1 Analogs Clicked in the C Domain: Chemical Synthesis and Biological Activities

    Czech Academy of Sciences Publication Activity Database

    Macháčková, Kateřina; Collinsová, Michaela; Chrudinová, Martina; Selicharová, Irena; Pícha, Jan; Buděšínský, Miloš; Vaněk, Václav; Žáková, Lenka; Brzozowski, A. M.; Jiráček, Jiří

    2017-01-01

    Roč. 60, č. 24 (2017), s. 10105-10117 ISSN 0022-2623 Institutional support: RVO:61388963 Keywords : IGF-1 * receptor * synthesis * triazole Subject RIV: CE - Biochemistry Impact factor: 6.259, year: 2016 http://pubs.acs.org/doi/full/10.1021/acs.jmedchem.7b01331

  2. Analog current mode analog/digital converter

    Science.gov (United States)

    Hadidi, Khayrollah (Inventor)

    1996-01-01

    An improved subranging or comparator circuit is provided for an analog-to-digital converter. As a subranging circuit, the circuit produces a residual signal representing the difference between an analog input signal and an analog of a digital representation. This is achieved by subdividing the digital representation into two or more parts and subtracting from the analog input signal analogs of each of the individual digital portions. In another aspect of the present invention, the subranging circuit comprises two sets of differential input pairs in which the transconductance of one differential input pair is scaled relative to the transconductance of the other differential input pair. As a consequence, the same resistor string may be used for two different digital-to-analog converters of the subranging circuit.

  3. Science Teachers' Analogical Reasoning

    Science.gov (United States)

    Mozzer, Nilmara Braga; Justi, Rosária

    2013-08-01

    Analogies can play a relevant role in students' learning. However, for the effective use of analogies, teachers should not only have a well-prepared repertoire of validated analogies, which could serve as bridges between the students' prior knowledge and the scientific knowledge they desire them to understand, but also know how to introduce analogies in their lessons. Both aspects have been discussed in the literature in the last few decades. However, almost nothing is known about how teachers draw their own analogies for instructional purposes or, in other words, about how they reason analogically when planning and conducting teaching. This is the focus of this paper. Six secondary teachers were individually interviewed; the aim was to characterize how they perform each of the analogical reasoning subprocesses, as well as to identify their views on analogies and their use in science teaching. The results were analyzed by considering elements of both theories about analogical reasoning: the structural mapping proposed by Gentner and the analogical mechanism described by Vosniadou. A comprehensive discussion of our results makes it evident that teachers' content knowledge on scientific topics and on analogies as well as their pedagogical content knowledge on the use of analogies influence all their analogical reasoning subprocesses. Our results also point to the need for improving teachers' knowledge about analogies and their ability to perform analogical reasoning.

  4. A novel protein-engineered hepatocyte growth factor analog released via a shear-thinning injectable hydrogel enhances post-infarction ventricular function.

    Science.gov (United States)

    Steele, Amanda N; Cai, Lei; Truong, Vi N; Edwards, Bryan B; Goldstone, Andrew B; Eskandari, Anahita; Mitchell, Aaron C; Marquardt, Laura M; Foster, Abbygail A; Cochran, Jennifer R; Heilshorn, Sarah C; Woo, Y Joseph

    2017-10-01

    In the last decade, numerous growth factors and biomaterials have been explored for the treatment of myocardial infarction (MI). While pre-clinical studies have demonstrated promising results, clinical trials have been disappointing and inconsistent, likely due to poor translatability. In the present study, we investigate a potential myocardial regenerative therapy consisting of a protein-engineered dimeric fragment of hepatocyte growth factor (HGFdf) encapsulated in a shear-thinning, self-healing, bioengineered hydrogel (SHIELD). We hypothesized that SHIELD would facilitate targeted, sustained intramyocardial delivery of HGFdf thereby attenuating myocardial injury and post-infarction remodeling. Adult male Wistar rats (n = 45) underwent sham surgery or induction of MI followed by injection of phosphate buffered saline (PBS), 10 μg HGFdf alone, SHIELD alone, or SHIELD encapsulating 10 μg HGFdf. Ventricular function, infarct size, and angiogenic response were assessed 4 weeks post-infarction. Treatment with SHIELD + HGFdf significantly reduced infarct size and increased both ejection fraction and borderzone arteriole density compared to the controls. Thus, sustained delivery of HGFdf via SHIELD limits post-infarction adverse ventricular remodeling by increasing angiogenesis and reducing fibrosis. Encapsulation of HGFdf in SHIELD improves clinical translatability by enabling minimally-invasive delivery and subsequent retention and sustained administration of this novel, potent angiogenic protein analog. Biotechnol. Bioeng. 2017;114: 2379-2389. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  6. Components of Geometric Analogy Solution.

    Science.gov (United States)

    Mulholland, Timothy M.; And Others

    1980-01-01

    Adults' geometric analogy solution was investigated as a function of systematic variations in the information structure of items. Latency data from verification of true and false items were recorded. A model incorporating assumptions about the form of item representation, working memory factors, and processing components and strategies was…

  7. Preclinical evaluation of the engineered stem cell chemokine stromal cell-derived factoranalog in a translational ovine myocardial infarction model.

    Science.gov (United States)

    Macarthur, John W; Cohen, Jeffrey E; McGarvey, Jeremy R; Shudo, Yasuhiro; Patel, Jay B; Trubelja, Alen; Fairman, Alexander S; Edwards, Bryan B; Hung, George; Hiesinger, William; Goldstone, Andrew B; Atluri, Pavan; Wilensky, Robert L; Pilla, James J; Gorman, Joseph H; Gorman, Robert C; Woo, Y Joseph

    2014-02-14

    After myocardial infarction, there is an inadequate blood supply to the myocardium, and the surrounding borderzone becomes hypocontractile. To develop a clinically translatable therapy, we hypothesized that in a preclinical ovine model of myocardial infarction, the modified endothelial progenitor stem cell chemokine, engineered stromal cell-derived factoranalog (ESA), would induce endothelial progenitor stem cell chemotaxis, limit adverse ventricular remodeling, and preserve borderzone contractility. Thirty-six adult male Dorset sheep underwent permanent ligation of the left anterior descending coronary artery, inducing an anteroapical infarction, and were randomized to borderzone injection of saline (n=18) or ESA (n=18). Ventricular function, geometry, and regional strain were assessed using cardiac MRI and pressure-volume catheter transduction. Bone marrow was harvested for in vitro analysis, and myocardial biopsies were taken for mRNA, protein, and immunohistochemical analysis. ESA induced greater chemotaxis of endothelial progenitor stem cells compared with saline (P<0.01) and was equivalent to recombinant stromal cell-derived factor 1α (P=0.27). Analysis of mRNA expression and protein levels in ESA-treated animals revealed reduced matrix metalloproteinase 2 in the borderzone (P<0.05), with elevated levels of tissue inhibitor of matrix metalloproteinase 1 and elastin in the infarct (P<0.05), whereas immunohistochemical analysis of borderzone myocardium showed increased capillary and arteriolar density in the ESA group (P<0.01). Animals in the ESA treatment group also had significant reductions in infarct size (P<0.01), increased maximal principle strain in the borderzone (P<0.01), and a steeper slope of the end-systolic pressure-volume relationship (P=0.01). The novel, biomolecularly designed peptide ESA induces chemotaxis of endothelial progenitor stem cells, stimulates neovasculogenesis, limits infarct expansion, and preserves contractility in an ovine

  8. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  9. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  10. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  11. EFFECTS OF THE APPLICATION OF A PSYCHOPROPHYLACTIC METHOD DURING THE PARTURITION PROCESS ON THE PAIN, THE ANXIETY AND THE CORTICOTROPHIN HORMONE RELEASE

    Directory of Open Access Journals (Sweden)

    Nilza Alves Marques Almeida

    2002-12-01

    Full Text Available Psychoprophylactic techniques for childbirth were evaluated in the immediate nursery attendance for mother inlabor. It was evaluated the techniques effect on pain intensity and anxiety levels, as well as on the corticotrophinhormone (ACTH release. It was studied mother participation in different phases of childbirth labor and childdelivery, her vision on nursery psychoprophylactic assistance before delivery, and her perception on labor. Traceand state of anxiety, pain intensity and plasma ACTH levels were determined. Experimental research was carriedout with a quantitative and qualitative approach at a Public Maternity Hospital of the City of Goiânia in the State ofGoiás, Brazil. The sample consisted of thirty six primigravidas women that didn´t receive childbirth preparatoryclasses. Nineteen parturients received both individual nursery and labor psychoprophylactic assistance(experimental group – GE while seventeen parturient received only maternity routine assistance (control group -GC. For both groups, Visual Analogic Scale (VAS application and, State-Trait Anxiety Inventory (STAI wereperformed, as well as peripheric blood sampling and immediate postparturition interview. Results allowed toconclude that: 1. Psychoprophylactic techniques for immediate assistance to GE group have demanded theiractive participation and effective nurse intervention. Better parturient performance, relief to pain sensation,encouragement to feel labor process, with increase of positive opinions over normal child delivery, were promoted.A lower level of anxiety for a larger period of time, when considered the absolute values, was also observed; 2.Significant attributes to the assistance received during labor reflected the importance of the direct parturientassistance and childbirth preparation, even if in the immediate antecedent period; 3. High variability of ACTHplasma levels in both groups was observed, with no statistical difference between them. Correlation

  12. Inducción a la maduración y desove del robalo (centropomus nigrescens) en cautiverío mediante la utilización del las hormonas hcg (gonadotropina coriónica humana) y lhrha (luteinizing hormone releasing hormone ethylamide)

    OpenAIRE

    Carvajal Veloz, Miguel

    1997-01-01

    Inducción a la maduración y desove del robalo (Centropomus nigrescens) en cautiverio mediante la utilización del las hormonas HCG (Gonadotropina Coriónica Humana) y LHRHa (Luteinizing Hormone Releasing Hormone Ethylamide) El principal problema que presenta el cultivo del robalo Centropomus nigrescens es la inhibición de su ciclo reproductivo en cautiverio.

  13. Identification of corticotropin-releasing factor (CRF) target cells and effects of dexamethasone on binding in anterior pituitary using a fluorescent analog of CRF

    DEFF Research Database (Denmark)

    Schwartz, J; Billestrup, Nils; Perrin, M

    1986-01-01

    . Fluorescence was eliminated by coincubation with a 200-fold excess of unlabeled CRF. Treatment with dexamethasone (10(-9)-10(-7) M) decreased visible fluorescence in a dose-dependent manner. These results demonstrate the utility of a fluorescent CRF analog for identification of cells with specific CRF...

  14. The 2-oxoglutarate analog 3-oxoglutarate decreases normoxic hypoxia-inducible factor-1α in cancer cells, induces cell death, and reduces tumor xenograft growth

    Directory of Open Access Journals (Sweden)

    Koivunen P

    2016-03-01

    Full Text Available Peppi Koivunen,1 Stuart M Fell,2,3 Wenyun Lu,4 Joshua D Rabinowitz,4 Andrew L Kung,5,6 Susanne Schlisio,2,7 1Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland; 2Ludwig Institute for Cancer Research Ltd, Stockholm, Sweden; 3Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden; 4Department of Chemistry and Integrative Genomics, Princeton University, Princeton, NJ, 5Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, 6Department of Pediatrics, Columbia University Medical Center, New York, NY, USA; 7Department of Microbiology and Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden Abstract: The cellular response to hypoxia is primarily regulated by the hypoxia-inducible factors (HIFs. HIF-1α is also a major mediator of tumor physiology, and its abundance is correlated with therapeutic resistance in a broad range of cancers. Accumulation of HIF-1α under hypoxia is mainly controlled by the oxygen-sensing HIF prolyl 4-hydroxylases (EGLNs, also known as PHDs. Here, we identified a high level of normoxic HIF-1α protein in various cancer cell lines. EGLNs require oxygen and 2-oxoglutarate for enzymatic activity. We tested the ability of several cell-permeable 2-oxoglutarate analogs to regulate the abundance of HIF-1α protein. We identified 3-oxoglutarate as a potent regulator of HIF-1α in normoxic conditions. In contrast to 2-oxoglutarate, 3-oxoglutarate decreased the abundance of HIF-1α protein in several cancer cell lines in normoxia and diminished HIF-1α levels independent of EGLN enzymatic activity. Furthermore, we observed that 3-oxoglutarate was detrimental to cancer cell survival. We show that esterified 3-oxoglutarate, in combination with the cancer chemotherapeutic drug vincristine, induces apoptosis and inhibits tumor growth in vitro and in vivo. Our data

  15. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; van den Boom, Jeroen M.; Dijkmans, Eise C.

    2001-01-01

    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is

  16. Digital to Analog Converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.; van den Boom, Jeroen M.; Dijkmans, Eise C.

    2006-01-01

    A digital to analog converter (DAC) for converting a digital signal (DS) having a maximum voltage range which corresponds to a first supply voltage (UL) into an analog signal (UOUT) having a maximum voltage range which corresponds to a second supply voltage (UH). The first supply voltage (UL) is

  17. Hydraulic Capacitor Analogy

    Science.gov (United States)

    Baser, Mustafa

    2007-03-01

    Students have difficulties in physics because of the abstract nature of concepts and principles. One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding.2,3 According to Iding,4 analogies are consistent with the tenets of constructivist learning theories, which claim that learners should be actively involved and new concepts should be based on learners' previous experiences. When analogies are used during the teaching-learning process, they may promote students' understanding of abstract science concepts.5 This paper suggests a capacitor analogy that aims to foster students' conceptual understanding of capacitors in a slightly different way than Greenslade's analogy.6

  18. Meat analog: a review.

    Science.gov (United States)

    Malav, O P; Talukder, S; Gokulakrishnan, P; Chand, S

    2015-01-01

    The health-conscious consumers are in search of nutritious and convenient food item which can be best suited in their busy life. The vegetarianism is the key for the search of such food which resembles the meat in respect of nutrition and sensory characters, but not of animal origin and contains vegetable or its modified form, this is the point when meat analog evolved out and gets shape. The consumers gets full satisfaction by consumption of meat analog due to its typical meaty texture, appearance and the flavor which are being imparted during the skilled production of meat analog. The supplement of protein in vegetarian diet through meat alike food can be fulfilled by incorporating protein-rich vegetative food grade materials in meat analog and by adopting proper technological process which can promote the proper fabrication of meat analog with acceptable meat like texture, appearance, flavor, etc. The easily available vegetables, cereals, and pulses in India have great advantages and prospects to be used in food products and it can improve the nutritional and functional characters of the food items. The various form and functional characters of food items are available world over and attracts the meat technologists and the food processors to bring some innovativeness in meat analog and its presentation and marketability so that the acceptability of meat analog can be overgrown by the consumers.

  19. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  20. Antibacterial and Antibiofilm Activities of Makaluvamine Analogs

    Directory of Open Access Journals (Sweden)

    Bhavitavya Nijampatnam

    2014-09-01

    Full Text Available Streptococcus mutans is a key etiological agent in the formation of dental caries. The major virulence factor is its ability to form biofilms. Inhibition of S. mutans biofilms offers therapeutic prospects for the treatment and the prevention of dental caries. In this study, 14 analogs of makaluvamine, a marine alkaloid, were evaluated for their antibacterial activity against S. mutans and for their ability to inhibit S. mutans biofilm formation. All analogs contained the tricyclic pyrroloiminoquinone core of makaluvamines. The structural variations of the analogs are on the amino substituents at the 7-position of the ring and the inclusion of a tosyl group on the pyrrole ring N of the makaluvamine core. The makaluvamine analogs displayed biofilm inhibition with IC50 values ranging from 0.4 μM to 88 μM. Further, the observed bactericidal activity of the majority of the analogs was found to be consistent with the anti-biofilm activity, leading to the conclusion that the anti-biofilm activity of these analogs stems from their ability to kill S. mutans. However, three of the most potent N-tosyl analogs showed biofilm IC50 values at least an order of magnitude lower than that of bactericidal activity, indicating that the biofilm activity of these analogs is more selective and perhaps independent of bactericidal activity.

  1. TV Analog Station Transmitters

    Data.gov (United States)

    Department of Homeland Security — This file is an extract from the Consolidated Database System (CDBS) licensed by the Media Bureau. It consists of Analog Television Stations (see Rule Part47 CFR...

  2. Challenges in Analogical Reasoning

    CERN Document Server

    Lin, Shih-Yin

    2016-01-01

    Learning physics requires understanding the applicability of fundamental principles in a variety of contexts that share deep features. One way to help students learn physics is via analogical reasoning. Students can be taught to make an analogy between situations that are more familiar or easier to understand and another situation where the same physics principle is involved but that is more difficult to handle. Here, we examine introductory physics students' ability to use analogies in solving problems involving Newton's second law. Students enrolled in an algebra-based introductory physics course were given a solved problem involving tension in a rope and were then asked to solve another problem for which the physics is very similar but involved a frictional force. They were asked to point out the similarities between the two problems and then use the analogy to solve the friction problem.

  3. The effect of short-term cortisol changes on growth hormone responses to the pyridostigmine-growth-hormone-releasing-hormone test in healthy adults and patients with suspected growth hormone deficiency

    DEFF Research Database (Denmark)

    Andersen, M; Støving, R K; Hangaard, J

    1998-01-01

    BACKGROUND AND AIMS: The interaction between cortisol and growth hormone (GH)-levels may significantly influence GH-responses to a stimulation test. In order to systematically analyse the interaction in a paired design, it is necessary to use a test, which has been proven safe and reliable such a...... nor by conventional HC therapy itself. However, our results also demonstrated that a GH-stimulation test should not be performed on patients, suffering from acute stress....... such as the pyridostigmine-growth-hormone-releasing-hormone (PD-GHRH) test. Three groups of subjects with a different GH-secretory capacity were included. STUDY A: Eight healthy adults were tested seven times, once with placebo throughout the examination and six times with the PD-GHRH test following no glucocorticoid......-responses to a PD-GHRH test were reduced in all individuals during acute stress-appropriate cortisol levels and the percentage reduction in GH-levels was independent of the GH-secretory capacity. Clinically, we found that peak GH-responses were not significantly affected by a short break in conventional HC therapy...

  4. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  5. A super-agonist of growth hormone-releasing hormone causes rapid improvement of nutritional status in patients with chronic kidney disease.

    Science.gov (United States)

    Niemczyk, Stanisław; Sikorska, Hanna; Wiecek, Andrzej; Zukowska-Szczechowska, Ewa; Załecka, Klaudia; Gorczyńska, Joanna; Kubik, Małgorzata; Czerwieńska, Beata; Gosek, Katarzyna; Veldhuis, Johannes D; Wagner, David A; Gaudreau, Pierrette; Hakonen, Tiina; Kay, Sam Wai Kit; Jouhikainen, Taneli; Schaefer, Franz

    2010-03-01

    Chronic kidney disease is frequently associated with protein-energy wasting related to chronic inflammation and a resistance to anabolic hormones such as insulin and growth hormone (GH). In this study, we determined whether a new GH-releasing hormone super-agonist (AKL-0707) improved the anabolism and nutritional status of nondialyzed patients with stage 4-5 chronic kidney disease randomized to twice daily injections of the super-agonist or placebo. After 28 days, this treatment significantly increased 24-h GH secretion by almost 400%, without altering the frequency or rhythmicity of secretory bursts or fractional pulsatile GH release, and doubled the serum insulin-like growth factor-1 level. There was a significant change in the Subjective Global Assessment from 'mildly to moderately malnourished' to 'well-nourished' in 6 of 9 patients receiving AKL-0707 but in none of 10 placebo-treated patients. By dual-energy X-ray absorptiometry, both the mean fat-free mass and the body mineral content increased, but fat mass decreased, all significantly. In the AKL-0707-treated group, both serum urea and normalized protein equivalent of nitrogen appearance significantly decreased with no change in dietary protein intake, indicating a protein anabolic effect of treatment. Thus, our study shows that stimulation of endogenous GH secretion by AKL-0707 overcomes uremic catabolism of patients with advanced chronic kidney disease.

  6. Kisspeptin Stimulates Growth Hormone Release by Utilizing Neuropeptide Y Pathways and Is Dependent on the Presence of Ghrelin in the Ewe.

    Science.gov (United States)

    Foradori, Chad D; Whitlock, Brian K; Daniel, Jay A; Zimmerman, Arthur D; Jones, Melaney A; Read, Casey C; Steele, Barbara P; Smith, Jeremy T; Clarke, Iain J; Elsasser, Theodore H; Keisler, Duane H; Sartin, James L

    2017-10-01

    Although kisspeptin is the primary stimulator of gonadotropin-releasing hormone secretion and therefore the hypothalamic-pituitary-gonadal axis, recent findings suggest kisspeptin can also regulate additional neuroendocrine processes including release of growth hormone (GH). Here we show that central delivery of kisspeptin causes a robust rise in plasma GH in fasted but not fed sheep. Kisspeptin-induced GH secretion was similar in animals fasted for 24 hours and those fasted for 72 hours, suggesting that the factors involved in kisspeptin-induced GH secretion are responsive to loss of food availability and not the result of severe negative energy balance. Pretreatment with the neuropeptide Y (NPY) Y1 receptor antagonist, BIBO 3304, blocked the effects of kisspeptin-induced GH release, implicating NPY as an intermediary. Kisspeptin treatment induced c-Fos in NPY and GH-releasing hormone (GHRH) cells of the arcuate nucleus. The same kisspeptin treatment resulted in a reduction in c-Fos in somatostatin (SS) cells in the periventricular nucleus. Finally, blockade of systemic ghrelin release or antagonism of the ghrelin receptor eliminated or reduced the ability of kisspeptin to induce GH release, suggesting the presence of ghrelin is required for kisspeptin-induced GH release in fasted animals. Our findings support the hypothesis that during short-term fasting, systemic ghrelin concentrations and NPY expression in the arcuate nucleus rise. This permits kisspeptin activation of NPY cells. In turn, NPY stimulates GHRH cells and inhibits SS cells, resulting in GH release. We propose a mechanism by which kisspeptin conveys reproductive and hormone status onto the somatotropic axis, resulting in alterations in GH release. Copyright © 2017 Endocrine Society.

  7. Role of fibroblast growth factor 19 in the control of glucose homeostasis

    NARCIS (Netherlands)

    Schaap, Frank G.

    2012-01-01

    Purpose of review Fibroblast growth factor 19 (FGF19) is a postprandial hormone released from the small intestine. FGF19 improves glucose tolerance when overexpressed in mice with impaired glucose tolerance or diabetes. This review summarizes the recent advances in our understanding of the biology

  8. Anti-inflammatory effect of thalidomide dithiocarbamate and dithioate analogs.

    Science.gov (United States)

    Talaat, Roba; El-Sayed, Waheba; Agwa, Hussein S; Gamal-Eldeen, Amira M; Moawia, Shaden; Zahran, Magdy A H

    2015-08-05

    Thalidomide has anti-inflammatory, immunomodulatory, and anti-angiogenic properties. It has been used to treat a variety of cancers and autoimmune diseases. This study aimed to characterize anti-inflammatory activities of novel thalidomide analogs by exploring their effects on splenocytes proliferation and macrophage functions and their antioxidant activity. MTT assay was used to assess the cytotoxic effect of thalidomide analogs against splenocytes. Tumor necrosis factor (TNF-α) and nuclear factor kappa B (NF-κB-P65) were determined by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) was estimated by colorimetric assay. Antioxidant activity was examined by ORAC assay. Our results demonstrated that thalidomide dithioate analog 2 and thalidomide dithiocarbamate analog 4 produced a slight increase in splenocyte proliferation compared with thalidomide. Thalidomide dithiocarbamate analog 1 is a potent inhibitor of TNF-α production, whereas thalidomide dithiocarbamate analog 5 is a potent inhibitor of both TNF-α and NO. Analog 2 has a pronounced inhibitory effect on NF-κB-P65 production level. All thalidomide analogs showed prooxidant activity against hydroxyl (OH) radical. Analog 1 and thalidomide dithioate analog 3 have prooxidant activity against peroxyl (ROO) radical in relation to thalidomide. On the other hand, analog 4 has a potent scavenging capacity against peroxyl (ROO) radical compared with thalidomide. Taken together, the results of this study suggest that thalidomide analogs might have valuable anti-inflammatory activities with more pronounced effect than thalidomide itself. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. Analog Frame Store Memory.

    Science.gov (United States)

    1980-01-15

    enhancement when coupled with the video acquisition performed by the Frame Store Memory in mode 2. 3 -11 It cr (A 3 coJ 0( kLL P.- FAIRCHILO IMAGING ...AD-AOSI 979 FAIRCHILD IMAGING SYSTEMS SYOSSET N Y F/0 17/2 ANALOG FRAME STORE MEMORY . CU) JAN 80 OAAK77-C-0165 UNCLASSIFIED ED-CX-141-5 M 1 .0 H " 1...DESCRIPTION 1-2 1.1.1 Analog Frame Store Memory 1-2 1.1.2 Analog Field Storage Device 1-4 1.1.3 Image Analyzer Digital Display (IADD) 1-4 1.2 PROGRAM’S

  10. CMOS analog circuit design

    CERN Document Server

    Allen, Phillip E

    1987-01-01

    This text presents the principles and techniques for designing analog circuits to be implemented in a CMOS technology. The level is appropriate for seniors and graduate students familiar with basic electronics, including biasing, modeling, circuit analysis, and some familiarity with frequency response. Students learn the methodology of analog integrated circuit design through a hierarchically-oriented approach to the subject that provides thorough background and practical guidance for designing CMOS analog circuits, including modeling, simulation, and testing. The authors' vast industrial experience and knowledge is reflected in the circuits, techniques, and principles presented. They even identify the many common pitfalls that lie in the path of the beginning designer--expert advice from veteran designers. The text mixes the academic and practical viewpoints in a treatment that is neither superficial nor overly detailed, providing the perfect balance.

  11. Analogical Reasoning in Geometry Education

    Science.gov (United States)

    Magdas, Ioana

    2015-01-01

    The analogical reasoning isn't used only in mathematics but also in everyday life. In this article we approach the analogical reasoning in Geometry Education. The novelty of this article is a classification of geometrical analogies by reasoning type and their exemplification. Our classification includes: analogies for understanding and setting a…

  12. Conversion to monotherapy with luteinizing-hormone releasing hormone agonist or orchiectomy after reaching PSA nadir following maximal androgen blockade is able to prolong progression-free survival in patients with metastatic prostate cancer: A propensity score matching analysis.

    Science.gov (United States)

    Min, Gyeong Eun; Ahn, Hanjong

    2017-06-01

    The present study evaluated androgen deprivation methods to determine the approach that most improves the progression-free survival (PFS) of patients with metastatic prostate cancer. Patients had received continuous maximal androgen blockade (MAB) or monotherapy [luteinizing-hormone releasing hormone (LHRH) agonist or orchiectomy] following the reaching of the prostate specific antigen (PSA) nadir. The medical records of 293 patients who received MAB following a diagnosis of metastatic prostate cancer were retrospectively reviewed. Following attainment of the PSA nadir and treatment with MAB, patients were maintained on continuous MAB (group CMAB) or converted to monotherapy (group MONO). Disease progression, defined as progression to castration-resistant prostate cancer, was evaluated and compared between the treatment modalities. PFS was compared between patients who received CMAB vs. MONO using 2:1 (102:53) propensity score matching; the basic clinicopathological characteristics (age, Gleason score, PSA and extent of bone metastasis) were similar between the groups. Disease progression was observed in 70.9% of all patients, with a median treatment period of 22.7 months. The median PFS time was 19.5 months in the CMAB group and 28.8 months in the MONO group (P=0.008). Kaplan-Meier analysis demonstrated that PFS was significantly associated with the type of maintenance androgen deprivation therapy (ADT; log rank bone metastasis were independent predictors of prolonged PFS. In this propensity score matched-analysis, conversion to monotherapy with a LHRH agonist or orchiectomy following attainment of the PSA nadir with initial MAB, prolonged the PFS, suggesting that monotherapy maintenance following initial MAB may benefit patients by reducing side effects without decreasing treatment efficacy.

  13. Is the growth outcome of children with idiopathic short stature and isolated growth hormone deficiency following treatment with growth hormone and a luteinizing hormone-releasing hormone agonist superior to that obtained by GH alone?

    Science.gov (United States)

    Colmenares, Ana; González, Laura; Gunczler, Peter; Lanes, Roberto

    2012-01-01

    The aim of this study was to evaluate the effect of combined therapy with growth hormone (GH) and luteinizing hormone-releasing hormone agonist (LHRHa) on the near-final height (NFH) of children with idiopathic short stature (ISS) and growth hormone deficiency (GHD) in early puberty. A retrospective analysis of 20 patients with ISS and 9 patients with GHD treated with combined therapy was undertaken. Twelve children with ISS and ten with GHD, treated with GH alone, served as controls. Patients were matched at baseline for chronological age, bone age, height standard deviation score (SDS), and pubertal development. Patients with ISS or GHD treated with combined therapy improved both their predicted adult height (PAH) at 2 years of therapy (ISS, p children, an increase of 7.9 +/- 4.9 cm with combined therapy vs. 7.3 +/- 6.0 cm with GH; GHD children, an increase of 6.8 +/- 7.8 cm with combined therapy vs. 5 +/- 5.9 cm with GH). The total height gain SDS was higher in patients treated with GH alone compared with those with combined therapy, but the difference was not significant (ISS children, a gain of 2.4 SDS with GH vs. 0.8 SDS with combined therapy; GHD children, a gain of 1.8 SDS with GH vs. 0.6 SDS with combined therapy). Although 2 years of combined treatment with GH and LHRHa improved the PAH and the NFH of ISS and GHD patients in early puberty, this improvement was not significant compared with that observed in similar subjects treated with GH alone.

  14. Restoration of Spermatogenesis Using a New Combined Herbal Formula of Epimedium koreanum Nakai and Angelica gigas Nakai in an Luteinizing Hormone-Releasing Hormone Agonist-Induced Rat Model of Male Infertility.

    Science.gov (United States)

    Park, Hyun Jun; Koo, Yean Kyoung; Park, Min Jung; Hwang, Yoon Kyung; Hwang, Sung Yeoun; Park, Nam Cheol

    2017-10-25

    We investigated the protective effect of a mixture of 2 herbal extracts, KH-465, which consisted of Epimedium koreanum Nakai and Angelica gigas Nakai, on spermatogenesis in a luteinizing hormone-releasing hormone (LHRH) agonist-induced rat model of male infertility. Seventy-five 12-week-old male Sprague-Dawley rats were randomly divided into 5 groups, containing 15 rats each: a normal control group that received no treatment and 4 experimental groups (I, II, III, and IV) in which an LHRH agonist was administered for 4 weeks to induce spermatogenic failure. Group I received distilled water, and groups II, III, and IV received 200 mg/kg/day of KH-465, 400 mg/kg/day KH-465, and depo-testosterone for 4 weeks, respectively. Weight changes of the testis and epididymis, sperm count motility, and levels of testosterone (T), free T, follicle-stimulating hormone (FSH), luteinizing hormone (LH), superoxide dismutase (SOD), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were estimated. Body, testis, and epididymis weight showed no significant differences among the control and experimental groups. Treatment with KH-465 increased the sperm count and motility. Serum hormone levels of T, free T, and FSH were not significantly different in the experimental groups, while the LH level was higher than in the LHRH agonist-induced control group, but not to a significant extent. Levels of SOD were higher and 8-OHdG were lower in the groups that received KH-465 than in the LHRH agonist-induced control group. Our results suggest that KH-465 increased sperm production via reducing oxidative stress and had a positive effect in a male infertility model.

  15. In vitro effect of. Delta. sup 9 -tetrahydrocannabinol to stimulate somatostatin release and block that of luteinizing hormone-releasing hormone by suppression of the release of prostaglandin E sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Rettori, V.; Aguila, M.C.; McCann, S.M. (Univ. of Texas Southwestern Medical Center at Dallas (United States)); Gimeno, M.F.; Franchi, A.M. (Centro de Estudios Farmacologicos y de Principios Naturales, Buenos Aires (Argentina))

    1990-12-01

    Previous in vivo studies have shown that {Delta}{sup 9}-tetrahydrocannabinol (THC), the principal active ingredient in marijuana, can suppress both luteinizing hormone (LH) and growth hormone (GH) secretion after its injection into the third ventricle of conscious male rats. The present studies were deigned to determine the mechanism of these effects. Various doses of THC were incubated with either stalk median eminence fragments (MEs) or mediobasal hypothalamic (MBH) fragments in vitro. Although THC (10 nM) did not alter basal release of LH-releasing hormone (LHRH) from MEs in vitro, it completely blocked the stimulatory action of dopamine or nonrepinephrine on LHRH release. The effective doses to block LHRH release were associated with a blockade of synthesis and release of prostaglandin E{sub 2} (PGE{sub 2}) from MBH in vitro. In contrast to the suppressive effect of THC on LHRH release, somatostatin release from MEs was enhanced in a dose-related manner with a minimal effective dose of 1 nM. Since PGE{sub 2} suppresses somatostatin release, this enhancement may also be related to the suppressive effect of THC on PGE{sub 2} synthesis and release. The authors speculate that these actions are mediated by the recently discovered THC receptors in the tissue. The results indicate that the suppressive effect of THC on LH release is mediated by a blockade of LHRH release, whereas the suppressive effect of the compound on growth hormone release is mediated, at least in part, by a stimulation of somatostatin release.

  16. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.

    1992-12-31

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  17. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.

    1992-01-01

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  18. Quantum Analog Computing

    Science.gov (United States)

    Zak, M.

    1998-01-01

    Quantum analog computing is based upon similarity between mathematical formalism of quantum mechanics and phenomena to be computed. It exploits a dynamical convergence of several competing phenomena to an attractor which can represent an externum of a function, an image, a solution to a system of ODE, or a stochastic process.

  19. How Analogy Drives Physics

    Energy Technology Data Exchange (ETDEWEB)

    Hofstadter, Doug (Indiana University)

    2004-05-05

    Many new ideas in theoretical physics come from analogies to older ideas in physics. For instance, the abstract notion of 'isospin' (or isotopic spin) originated in the prior concept of 'spin' (quantized angular momentum); likewise, the concept of 'phonon' (quantum of sound, or quantized collective excitation of a crystal) was based on the prior concept of 'photon' (quantum of light, or quantized element of the electromagnetic field). But these two examples, far from being exceptions, in fact represent the bread and butter of inventive thinking in physics. In a nutshell, intraphysics analogy-making -- borrowing by analogy with something already known in another area of physics -- is central to the progress of physics. The aim of this talk is to reveal the pervasiveness -- indeed, the indispensability -- of this kind of semi-irrational, wholly intuitive type of thinking (as opposed to more deductive mathematical inference) in the mental activity known as 'doing physics'. Speculations as to why wild analogical leaps are so crucial to the act of discovery in physics (as opposed to other disciplines) will be offered.

  20. The origins of enhanced activity in factor VIIa analogs and the interplay between key allosteric sites revealed by hydrogen exchange mass spectrometry

    DEFF Research Database (Denmark)

    Rand, Kasper D; Andersen, Mette D; Olsen, Ole H

    2008-01-01

    Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry to invest......Factor VIIa (FVIIa) circulates in the blood in a zymogen-like state. Only upon association with membrane-bound tissue factor (TF) at the site of vascular injury does FVIIa become active and able to initiate blood coagulation. Here we used hydrogen exchange monitored by mass spectrometry...

  1. Terrestrial Spaceflight Analogs: Antarctica

    Science.gov (United States)

    Crucian, Brian

    2013-01-01

    Alterations in immune cell distribution and function, circadian misalignment, stress and latent viral reactivation appear to persist during Antarctic winterover at Concordia Station. Some of these changes are similar to those observed in Astronauts, either during or immediately following spaceflight. Others are unique to the Concordia analog. Based on some initial immune data and environmental conditions, Concordia winterover may be an appropriate analog for some flight-associated immune system changes and mission stress effects. An ongoing smaller control study at Neumayer III will address the influence of the hypoxic variable. Changes were observed in the peripheral blood leukocyte distribution consistent with immune mobilization, and similar to those observed during spaceflight. Alterations in cytokine production profiles were observed during winterover that are distinct from those observed during spaceflight, but potentially consistent with those observed during persistent hypobaric hypoxia. The reactivation of latent herpesviruses was observed during overwinter/isolation, that is consistently associated with dysregulation in immune function.

  2. Antarctic analogs for Enceladus

    Science.gov (United States)

    Murray, A. E.; Andersen, D. T.; McKay, C. P.

    2014-12-01

    Enceladus is a new world for Astrobiology. The Cassini discovery of the icy plume emanating from the South Polar region indicates an active world, where detection of water, organics, sodium, and nano-particle silica in the plume strongly suggests that the source is a subsurface salty ocean reservoir. Recent gravity data from Cassini confirms the presence of a regional sea extending north to 50°S. An ocean habitat under a thick ice cover is perhaps a recurring theme in the Outer Solar System, but what makes Enceladus unique is that the plume jetting out into space is carrying samples of this ocean. Therefore, through the study of Enceladus' plumes we can gain new insights not only of a possible habitable world in the Solar Systems, but also about the formation and evolution of other icy-satellites. Cassini has been able to fly through this plume - effectively sampling the ocean. It is time to plan for future missions that do more detailed analyses, possibly return samples back to Earth and search for evidence of life. To help prepare for such missions, the need for earth-based analog environments is essential for logistical, methodological (life detection) and theoretical development. We have undertaken studies of two terrestrial environments that are close analogs to Enceladus' ocean: Lake Vida and Lake Untersee - two ice-sealed Antarctic lakes that represent physical, chemical and possibly biological analogs for Enceladus. By studying the diverse biology and physical and chemical constraints to life in these two unique lakes we will begin to understand the potential habitability of Enceladus and other icy moons, including possible sources of nutrients and energy, which together with liquid water are the key ingredients for life. Analog research such as this will also enable us to develop and test new strategies to search for evidence of life on Enceladus.

  3. Decreased Ability in the Segregation of Dynamically Changing Vowel-Analog Streams: A Factor in the Age-Related Cocktail-Party Deficit?

    Directory of Open Access Journals (Sweden)

    Pierre eDivenyi

    2014-06-01

    Full Text Available Pairs of harmonic complexes with different fundamental frequencies f0 (105 and 189 Hz or 105 and 136 Hz but identical bandwidth (0.25-3 kHz were band-pass filtered using a filter having an identical center frequency of 1 kHz. The filter’s center frequency was modulated using a triangular wave having a 5-Hz modulation frequency fmod to obtain a pair of vowel-analog waveforms with dynamically varying single-formant transitions. The target signal S contained a single modulation cycle starting either at a phase of - π /2 (up-down or π /2 (down-up, whereas the longer distracter N contained several cycles of the modulating triangular wave starting at a random phase. The level at which the target formant’s modulating phase could be correctly identified was adaptively determined for several distracter levels and several extents of frequency swing (10-55% in a group of experienced normal-hearing young and a group of experienced elderly individuals with hearing loss not exceeding one considered moderate. The most important result was that, for the two f0 differences, all distracter levels, and all frequency swing extents tested, elderly listeners needed about 20 dB larger S/N ratios than the young. Results also indicate that identification thresholds of both the elderly and the young listeners are between 4 and 12 dB higher than similarly determined detection thresholds and that, contrary to detection, identification is not a linear function of distracter level. Since formant transitions represent potent cues for speech intelligibility, the large S/N ratios required by the elderly for correct discrimination of single-formant transition dynamics may at least partially explain the well-documented intelligibility loss of speech in babble noise by the elderly. [Work supported by grants from the National Institute on Aging and the Veterans Affairs Medical Research.

  4. Decreased ability in the segregation of dynamically changing vowel-analog streams: a factor in the age-related cocktail-party deficit?

    Science.gov (United States)

    Divenyi, Pierre

    2014-01-01

    Pairs of harmonic complexes with different fundamental frequencies f0 (105 and 189 Hz or 105 and 136 Hz) but identical bandwidth (0.25-3 kHz) were band-pass filtered using a filter having an identical center frequency of 1 kHz. The filter's center frequency was modulated using a triangular wave having a 5-Hz modulation frequency fmod to obtain a pair of vowel-analog waveforms with dynamically varying single-formant transitions. The target signal S contained a single modulation cycle starting either at a phase of -π/2 (up-down) or π/2 (down-up), whereas the longer distracter N contained several cycles of the modulating triangular wave starting at a random phase. The level at which the target formant's modulating phase could be correctly identified was adaptively determined for several distracter levels and several extents of frequency swing (10-55%) in a group of experienced normal-hearing young and a group of experienced elderly individuals with hearing loss not exceeding one considered moderate. The most important result was that, for the two f0 differences, all distracter levels, and all frequency swing extents tested, elderly listeners needed about 20 dB larger S/N ratios than the young. Results also indicate that identification thresholds of both the elderly and the young listeners are between 4 and 12 dB higher than similarly determined detection thresholds and that, contrary to detection, identification is not a linear function of distracter level. Since formant transitions represent potent cues for speech intelligibility, the large S/N ratios required by the elderly for correct discrimination of single-formant transition dynamics may at least partially explain the well-documented intelligibility loss of speech in babble noise by the elderly.

  5. Human Factor Investigation of Waste Processing System During the HI-SEAS 4 Month Mars Analog Mission in Support of NASA's Logistic Reduction and Repurposing Project: Trash to Gas

    Science.gov (United States)

    Caraccio, Anne; Hintze, Paul; Miles, John D.

    2014-01-01

    NASAs Logistics Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is tasked with reducing total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. Trash to Gas (TtG) is a sub task to LRR with efforts focused on development of a technology that converts wastes generated during long duration space missions into high-value products such as methane, water for life support, raw material production feedstocks, and other energy sources. The reuse of discarded materials is a critical component to reducing overall mission mass. The 120 day Hawaii Space Exploration and Analog Simulation provides a unique opportunity to answer questions regarding crew interface and system analysis for designing and developing future flight-like versions of a TtG system. This paper will discuss the human factors that would affect the design of a TtG or other waste processing systems. An overview of the habitat, utility usage, and waste storage and generation is given. Crew time spent preparing trash for TtG processing was recorded. Gas concentrations were measured near the waste storage locations and at other locations in the habitat. In parallel with the analog mission, experimental processing of waste materials in a TtG reactor was performed in order to evaluate performance with realistic waste materials.

  6. Human Factor Investigation of Waste Processing System During the HI-SEAS 4-month Mars Analog Mission in Support of NASA's Logistic Reduction and Repurposing Project: Trash to Gas

    Science.gov (United States)

    Caraccio, Anne; Hintze, Paul E.; Miles, John D.

    2014-01-01

    NASA's Logistics Reduction and Repurposing (LRR) project is a collaborative effort in which NASA is tasked with reducing total logistical mass through reduction, reuse and recycling of various wastes and components of long duration space missions and habitats. Trash to Gas (TtG) is a sub task to LRR with efforts focused on development of a technology that converts wastes generated during long duration space missions into high-value products such as methane, water for life support, raw material production feedstocks, and other energy sources. The reuse of discarded materials is a critical component to reducing overall mission mass. The 120 day Hawaii Space Exploration and Analog Simulation provides a unique opportunity to answer questions regarding crew interface and system analysis for designing and developing future flight-like versions of a TtG system. This paper will discuss the human factors that would affect the design of a TtG or other waste processing systems. An overview of the habitat, utility usage, and waste storage and generation is given. Crew time spent preparing trash for TtG processing was recorded. Gas concentrations were measured near the waste storage locations and at other locations in the habitat. In parallel with the analog mission, experimental processing of waste materials in a TtG reactor was performed in order to evaluate performance with realistic waste materials.

  7. Assessment of factors influencing the within-batch seroprevalence of human enteropathogenic Yersinia spp. of pigs at slaughter age and the analogy with microbiology.

    Science.gov (United States)

    Vanantwerpen, G; Berkvens, D; De Zutter, L; Houf, K

    2017-02-01

    The microbiologically and serologically-based prevalence of human enteropathogenic Yersinia spp. at moment of slaughter varies between pig farms due to different herd-level factors. A face-to-face questionnaire concerning a broad range of farm aspects (e.g., management and housing system, biosecurity, and hygiene measurements) was performed on one hundred farms. Factors influencing the seropositivity of 7047 pigs against human pathogenic Yersinia spp. were determined and compared to the microbiology. At the slaughterhouse, pieces of diafragm of on average 70 slaughter pigs per batch were sampled to determine the level of antibodies against enteropathogenic Yersinia spp. After univariable mixed-effect logistic regressions, variables that were related to the seropositivity (pslaughter or during rearing is possible by changing farm management factors. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Analog design centering and sizing

    CERN Document Server

    Graeb, Helmut E

    2007-01-01

    Here is a compendium of fundamental problem formulations of analog design centering and sizing. It provides a differentiated knowledge about the many tasks of analog design centering and sizing. In particular, coverage formulates the worst-case problem. The book stands at the interface between process technology and design technology, detailing how the two are required to reach a solution. It presents a mathematically founded description based on numerical optimization and statistics. This volume will enable analog and mixed-signal designers to assess CAD solution methods that are presented to them as well as help developers of analog CAD tools to formulate and develop solution approaches for analog design centering and sizing.

  9. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  10. What makes an analogy difficult? The effects of order and causal structure on analogical mapping.

    Science.gov (United States)

    Keane, M T

    1997-07-01

    In 4 experiments, the author tested 2 factors that affect the difficulty of analogies: order of presentation of information and causal structure. Experiments 1, 2, and 4 showed robust order effects for the positioning of sentences-sentence pairs in a variety of mapping problems. Experiments 2, 3, and 4 revealed the effects of causal structure in these analogies. Experiment 3 showed that the beneficial effects of causal structure are most marked in thematic, mapping problems presented in a casual question-answering context. Experiment 4 dealt with the interaction between order and causal structure and showed that order effects occur only in the presence of causal structure. Of all the analogy models in the literature, the incremental analogy machine is the best predictor of these results.

  11. Albert Einstein, Analogizer Extraordinaire

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Where does deep insight in physics come from? It is tempting to think that it comes from the purest and most precise of reasoning, following ironclad laws of thought that compel the clear mind completely rigidly. And yet the truth is quite otherwise. One finds, when one looks closely at any major discovery, that the greatest of physicists are, in some sense, the most crazily daring and irrational of all physicists. Albert Einstein exemplifies this thesis in spades. In this talk I will describe the key role, throughout Albert Einstein's fabulously creative life, played by wild guesses made by analogy lacking any basis whatsoever in pure reasoning. In particular, in this year of 2007, the centenary of 1907, I will describe how over the course of two years (1905 through 1907) of pondering, Einstein slowly came, via analogy, to understand the full, radical consequences of the equation that he had first discovered and published in 1905, arguably the most famous equation of all time: E = mc2.

  12. Características testiculares de touros imunizados com vacina anti-hormônio liberador do hormônio luteinizante Testicular characteristics of bulls immunosterilized with anti-luteinizing hormone-releasing hormone vaccine

    Directory of Open Access Journals (Sweden)

    Ricardo Zanella

    2009-10-01

    Full Text Available O objetivo deste trabalho foi avaliar a ação imunoesterilizadora de uma vacina anti-hormônio liberador de hormônio luteinizante (LHRH, composta por ovalbumina-LHRH-7 e tiorredoxina-LHRH-7, em touros mestiços Nelore. Vinte e seis touros, com dois anos de idade, foram distribuídos aleatoriamente em dois grupos de 13 animais. No grupo I, os animais receberam uma dose e dois reforços da vacina nos dias 0, 141, e 287 do experimento. No grupo II, os animais não receberam nenhum tratamento (controle. Para avaliar o efeito da vacina nos touros, foi realizada a mensuração da circunferência escrotal no início do experimento e no dia do abate, 741 dias depois. Por ocasião do abate, também foi coletada uma amostra dos testículos para avaliação histológica. O grupo imunizado apresentou circunferência escrotal ao abate de 22±5,98 cm, menor do que a do grupo controle que foi de 35,6±2,4 cm. Na análise histológica dos animais do grupo imunizado, foi observada degeneração testicular com ausência de espermatozoides em 85% dos animais avaliados, os outros 15% apresentaram redução no número de espermatozoides, em comparação aos animais do grupo controle. A vacina anti-LHRH, com fusão de proteínas, é efetiva na castração imunológica de touros e deve ser considerada como alternativa para utilização na produção bovina extensiva no Brasil.The objective of this study was to evaluate the immunosterilization action of the anti-luteinizing hormone-releasing hormone (LHRH vaccine, composed with ovalbumin-LHRH-7 and thioredoxin-LHRH-7, in Nelore-cross bulls. Twenty-six 2-year old bulls were randomly assigned in two groups of 13 animals each. The animals of group I received a primary and two booster injections of the vaccine on days 0, 141, and 287 of the experiment. In group II, the control group, the bulls did not receive any type of treatment. Scrotal circumference was measured in the beginning of the experiment and at slaughter

  13. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew

    2001-01-01

    Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

  14. [Analogies and analogy research in technical biology and bionics].

    Science.gov (United States)

    Nachtigall, Werner

    2010-01-01

    The procedural approaches of Technical Biology and Bionics are characterized, and analogy research is identified as their common basis. The actual creative aspect in bionical research lies in recognizing and exploiting technically oriented analogies underlying a specific biological prototype to indicate a specific technical application.

  15. Non-analog Monte Carlo estimators for radiation momentum deposition

    Energy Technology Data Exchange (ETDEWEB)

    Densmore, Jeffery D [Los Alamos National Laboratory; Hykes, Joshua M [Los Alamos National Laboratory

    2008-01-01

    The standard method for calculating radiation momentum deposition in Monte Carlo simulations is the analog estimator, which tallies the change in a particle's momentum at each interaction with the matter. Unfortunately, the analog estimator can suffer from large amounts of statistical error. In this paper, we present three new non-analog techniques for estimating momentum deposition. Specifically, we use absorption, collision, and track-length estimators to evaluate a simple integral expression for momentum deposition that does not contain terms that can cause large amounts of statistical error in the analog scheme. We compare our new non-analog estimators to the analog estimator with a set of test problems that encompass a wide range of material properties and both isotropic and anisotropic scattering. In nearly all cases, the new non-analog estimators outperform the analog estimator. The track-length estimator consistently yields the highest performance gains, improving upon the analog-estimator figure of merit by factors of up to two orders of magnitude.

  16. Natural analog studies: Licensing perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bradbury, J.W. [Nuclear Regulatory Commission, Washington, DC (United States)

    1995-09-01

    This report describes the licensing perspective of the term {open_quotes}natural analog studies{close_quotes} as used in CFR Part 60. It describes the misunderstandings related to its definition which has become evident during discussions at the U.S Nuclear Regulatory Commission meetings and tries to clarify the appropriate applications of natural analog studies to aspects of repository site characterization.

  17. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J M

    2010-01-01

    The design of an analog-to-digital converter or digital-to-analog converter is one of the most fascinating tasks in micro-electronics. In a converter the analog world with all its intricacies meets the realm of the formal digital abstraction. Both disciplines must be understood for an optimum conversion solution. In a converter also system challenges meet technology opportunities. Modern systems rely on analog-to-digital converters as an essential part of the complex chain to access the physical world. And processors need the ultimate performance of digital-to-analog converters to present the results of their complex algorithms. The same progress in CMOS technology that enables these VLSI digital systems creates new challenges for analog-to-digital converters: lower signal swings, less power and variability issues. Last but not least, the analog-to-digital converter must follow the cost reduction trend. These changing boundary conditions require micro-electronics engineers to consider their design choices for...

  18. Learning Plate Tectonics Using a Pre-Analogy Step

    Science.gov (United States)

    Glesener, G. B.; Sandoval, W. A.

    2011-12-01

    Previous research has shown that children tend to demonstrate lower performance on analogical reasoning tasks at a causal relations level compared to most adults (Gentner & Toupin, 1986). This tendency is an obstacle that geoscience educators must overcome because of the high frequency of analogies used in geoscience pedagogy. In particular, analog models are used to convey complex systems of non-everyday/non-observable events found in nature, such as plate tectonics. Key factors in successful analogical reasoning that have been suggested by researchers include knowledge of the causal relations in the base analog (Brown & Kane, 1988; Gentner, 1988; Gentner & Toupin, 1986), and development of learning strategies and metaconceptual competence(Brown & Kane, 1988). External factors, such as guiding cues and hints have been useful cognitive supports that help students reason through analogical problems (Gick & Holyoak, 1980). Cognitive supports have been seen by researchers to decrease processing demands on retrieval and working memory (Richland, Zur, & Holyoak, 2007). We observed third and fourth graders learning about plate tectonics beginning with a pre-analogy step-a cognitive support activity a student can do before working with an analogy to understand the target. This activity was designed to aid students in developing their understanding of object attributes and relations within an analog model so that more focus can be placed on mapping the corresponding higher-order relations between the base and target. Students learned targeted concepts of plate tectonics, as measured by pre to post gains on items adapted from the Geosciences Concept Inventory. Analyses of classroom interaction showed that students used the object attributes and higher-order relations highlighted in the pre-analogy activity as resources to reason about plate boundaries and plate movement during earthquakes.

  19. Molecular modeling of fentanyl analogs

    Directory of Open Access Journals (Sweden)

    LJILJANA DOSEN-MICOVIC

    2004-11-01

    Full Text Available Fentanyl is a highly potent and clinically widely used narcotic analgesic. A large number of its analogs have been synthesized, some of which (sufentanil and alfentanyl are also in clinical use. Theoretical studies, in recent years, afforded a better understanding of the structure-activity relationships of this class of opiates and allowed insight into the molecular mechanism of the interactions of fentanyl analogs with their receptors. An overview of the current computational techniques for modeling fentanyl analogs, their receptors and ligand-receptor interactions is presented in this paper.

  20. Analog Systems for Gravity Duals

    OpenAIRE

    Hossenfelder, S.

    2014-01-01

    We show that analog gravity systems exist for charged, planar black holes in asymptotic Anti-de Sitter space. These black holes have been employed to describe, via the gauge-gravity duality, strongly coupled condensed matter systems on the boundary of AdS-space. The analog gravity system is a different condensed matter system that, in a suitable limit, describes the same bulk physics as the theory on the AdS boundary. This combination of the gauge-gravity duality and analog gravity therefore ...

  1. Analog filters in nanometer CMOS

    CERN Document Server

    Uhrmann, Heimo; Zimmermann, Horst

    2014-01-01

    Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

  2. Analog-to-digital converter

    Science.gov (United States)

    Lewyn, L. L. (Inventor)

    1965-01-01

    An analog to digital converter circuit arrangement is reported that is suitable for use in ultra fast pulse height analysis. The circuit uses series connected tunnel diodes to quantize a voltage signal into discrete levels.

  3. 6-alkynyl fucose is a bioorthogonal analog for O-fucosylation of epidermal growth factor-like repeats and thrombospondin type-1 repeats by protein O-fucosyltransferases 1 and 2.

    Science.gov (United States)

    Al-Shareffi, Esam; Chaubard, Jean-Luc; Leonhard-Melief, Christina; Wang, Sheng-Kai; Wong, Chi-Huey; Haltiwanger, Robert S

    2013-02-01

    Protein O-fucosyltransferase 1 (Pofut1) and protein O-fucosyltransferase 2 (Pofut2) add O-linked fucose at distinct consensus sequences in properly folded epidermal growth factor (EGF)-like repeats and thrombospondin type-1 (TSR) repeats, respectively. Glycan chain elongation past O-fucose can occur to yield a tetrasaccharide on EGF repeats and a disaccharide on TSRs. Elimination of Pofut1 in mice causes embryonic lethality with Notch-like phenotypes demonstrating that O-fucosylation of Notch is essential for its function. Similarly, elimination of Pofut2 results in an early embryonic lethal phenotype in mice, although the molecular mechanism for the lethality is unknown. The recent development of sugar analogs has revolutionized the study of glycans by providing a convenient method for labeling and tracking glycosylation. In order to study O-fucosylation, we took advantage of the recently developed reporter, 6-alkynyl fucose. Using the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), or "click" reaction, azido-biotin allows tagging and detection of 6AF-modified proteins. Here we examine whether proteins containing EGF repeats or TSRs with O-fucose consensus sequences are specifically modified with 6AF in cell culture. Using mass spectrometry (MS), we demonstrate that 6AF is efficiently incorporated onto the appropriate consensus sequences on EGF repeats and TSRs. Furthermore, the elongation of the O-fucose monosaccharide on EGF repeats and TSRs is not hampered when 6AF is used. These results show that 6AF is efficiently utilized in a truly bioorthogonal manner by Pofut1, Pofut2 and the enzymes that elongate O-fucose, providing evidence that 6AF is a significant new tool in the study of protein O-fucosylation.

  4. Analog regulation of metabolic demand

    Directory of Open Access Journals (Sweden)

    Muskhelishvili Georgi

    2011-03-01

    Full Text Available Abstract Background The 3D structure of the chromosome of the model organism Escherichia coli is one key component of its gene regulatory machinery. This type of regulation mediated by topological transitions of the chromosomal DNA can be thought of as an analog control, complementing the digital control, i.e. the network of regulation mediated by dedicated transcription factors. It is known that alterations in the superhelical density of chromosomal DNA lead to a rich pattern of differential expressed genes. Using a network approach, we analyze these expression changes for wild type E. coli and mutants lacking nucleoid associated proteins (NAPs from a metabolic and transcriptional regulatory network perspective. Results We find a significantly higher correspondence between gene expression and metabolism for the wild type expression changes compared to mutants in NAPs, indicating that supercoiling induces meaningful metabolic adjustments. As soon as the underlying regulatory machinery is impeded (as for the NAP mutants, this coherence between expression changes and the metabolic network is substantially reduced. This effect is even more pronounced, when we compute a wild type metabolic flux distribution using flux balance analysis and restrict our analysis to active reactions. Furthermore, we are able to show that the regulatory control exhibited by DNA supercoiling is not mediated by the transcriptional regulatory network (TRN, as the consistency of the expression changes with the TRN logic of activation and suppression is strongly reduced in the wild type in comparison to the mutants. Conclusions So far, the rich patterns of gene expression changes induced by alterations of the superhelical density of chromosomal DNA have been difficult to interpret. Here we characterize the effective networks formed by supercoiling-induced gene expression changes mapped onto reconstructions of E. coli's metabolic and transcriptional regulatory network. Our

  5. Teamwork in high-risk environments analogous to space

    Science.gov (United States)

    Kanki, Barbara G.

    1990-01-01

    Mountaineering expeditions combine a number of factors which make them potentially good analogs to the planetary exploration facet of long-duration space missions. A study of mountain climbing teams was conducted in order to evaluate the usefulness of the environment as a space analog and to specifically identify the factors and issues surrounding teamwork and 'successful' team performance in two mountaineering environments. This paper focuses on social/organizational factors, including team size and structure, leadership styles and authority structure which were found in the sample of 22 climb teams (122 individuals). The second major issue discussed is the construction of a valid performance measure in this high-risk environment.

  6. Analog electronics for radiation detection

    CERN Document Server

    2016-01-01

    Analog Electronics for Radiation Detection showcases the latest advances in readout electronics for particle, or radiation, detectors. Featuring chapters written by international experts in their respective fields, this authoritative text: Defines the main design parameters of front-end circuitry developed in microelectronics technologies Explains the basis for the use of complementary metal oxide semiconductor (CMOS) image sensors for the detection of charged particles and other non-consumer applications Delivers an in-depth review of analog-to-digital converters (ADCs), evaluating the pros and cons of ADCs integrated at the pixel, column, and per-chip levels Describes incremental sigma delta ADCs, time-to-digital converter (TDC) architectures, and digital pulse-processing techniques complementary to analog processing Examines the fundamental parameters and front-end types associated with silicon photomultipliers used for single visible-light photon detection Discusses pixel sensors ...

  7. Analogies in Science and Science Teaching

    Science.gov (United States)

    Brown, Simon; Salter, Susan

    2010-01-01

    Analogies are often used in science, but students may not appreciate their significance, and so the analogies can be misunderstood or discounted. For this reason, educationalists often express concern about the use of analogies in teaching. Given the important place of analogies in the discourse of science, it is necessary that students are…

  8. Analog Input Data Acquisition Software

    Science.gov (United States)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  9. A digital to analog converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.

    2000-01-01

    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching

  10. A digital to analog converter

    NARCIS (Netherlands)

    Westra, Jan R.; Annema, Anne J.

    2006-01-01

    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching

  11. Drawing Analogies to Deepen Learning

    Science.gov (United States)

    Fava, Michelle

    2017-01-01

    This article offers examples of how drawing can facilitate thinking skills that promote analogical reasoning to enable deeper learning. The instructional design applies cognitive principles, briefly described here. The workshops were developed iteratively, through feedback from student and teacher participants. Elements of the UK National…

  12. Designing analog circuits in CMOS

    NARCIS (Netherlands)

    Annema, Anne J.; Nauta, Bram; van Langevelde, Ronald; Tuinhout, Hans

    2004-01-01

    The evolution in CMOS technology dictated by Moore's Law is clearly beneficial for designers of digital circuits, but it presents difficult challenges, such as lowered nominal supply voltages, for their peers in the analog world who want to keep pace with this rapid progression. This article

  13. Paper Analogies Enhance Biology Teaching.

    Science.gov (United States)

    Stencel, John E.

    1997-01-01

    Describes how to use paper analogies as models to illustrate various concepts in biology, human anatomy, and physiology classes. Models include biochemical paper models, protein papergrams, a paper model of early brain development, and a 3-D paper model of a eukaryotic cell. (AIM)

  14. Crows spontaneously exhibit analogical reasoning.

    Science.gov (United States)

    Smirnova, Anna; Zorina, Zoya; Obozova, Tanya; Wasserman, Edward

    2015-01-19

    Analogical reasoning is vital to advanced cognition and behavioral adaptation. Many theorists deem analogical thinking to be uniquely human and to be foundational to categorization, creative problem solving, and scientific discovery. Comparative psychologists have long been interested in the species generality of analogical reasoning, but they initially found it difficult to obtain empirical support for such thinking in nonhuman animals (for pioneering efforts, see [2, 3]). Researchers have since mustered considerable evidence and argument that relational matching-to-sample (RMTS) effectively captures the essence of analogy, in which the relevant logical arguments are presented visually. In RMTS, choice of test pair BB would be correct if the sample pair were AA, whereas choice of test pair EF would be correct if the sample pair were CD. Critically, no items in the correct test pair physically match items in the sample pair, thus demanding that only relational sameness or differentness is available to support accurate choice responding. Initial evidence suggested that only humans and apes can successfully learn RMTS with pairs of sample and test items; however, monkeys have subsequently done so. Here, we report that crows too exhibit relational matching behavior. Even more importantly, crows spontaneously display relational responding without ever having been trained on RMTS; they had only been trained on identity matching-to-sample (IMTS). Such robust and uninstructed relational matching behavior represents the most convincing evidence yet of analogical reasoning in a nonprimate species, as apes alone have spontaneously exhibited RMTS behavior after only IMTS training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Immune Function Changes during a Spaceflight-Analog Undersea Mission

    Science.gov (United States)

    Crucian, Brian; Stowe, Raymond; Mehta, Satish; Quiniarte, Heather; Yetman, Deborah; Pierson, Duane; Sams, Clarence

    2008-01-01

    There is ample evidence to suggest that space flight leads to immune system dysregulation. This may be a result of microgravity, confinement, physiological stress, radiation, environment or other mission-associated factors. It is attractive to utilize ground-based spaceflight analogs as appropriate to investigate this phenomenon. For spaceflight-associated immune dysregulation (SAID), the authors believe the most appropriate analogs might be NEEMO (short duration, Shuttle analog), Antarctic winter-over (long-duration, ISS analog) and the Haughton Mars Project in the Canadian Arctic (intermediate-duration). Each of these analogs replicate isolation, mission-associated stress, disrupted circadian rhythms, and other aspects of flight thought to contribute to SAID. To validate NEEMO as a flight analog with respect to SAID, a pilot study was conducted during the NEEMO-12 and 13 missions during 2007. Assays were performed that assessed immune status, physiological stress and latent viral reactivation. Blood and saliva samples were collected at pre-, mid-, and post-mission timepoints.

  16. Analog circuit design art, science and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    This book is far more than just another tutorial or reference guide - it's a tour through the world of analog design, combining theory and applications with the philosophies behind the design process. Readers will learn how leading analog circuit designers approach problems and how they think about solutions to those problems. They'll also learn about the `analog way' - a broad, flexible method of thinking about analog design tasks.A comprehensive and useful guide to analog theory and applications. Covers visualizing the operation of analog circuits. Looks at how to rap

  17. Analog Nonvolatile Computer Memory Circuits

    Science.gov (United States)

    MacLeod, Todd

    2007-01-01

    In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value

  18. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel

    2017-01-01

    This textbook is appropriate for use in graduate-level curricula in analog-to-digital conversion, as well as for practicing engineers in need of a state-of-the-art reference on data converters. It discusses various analog-to-digital conversion principles, including sampling, quantization, reference generation, nyquist architectures and sigma-delta modulation. This book presents an overview of the state of the art in this field and focuses on issues of optimizing accuracy and speed, while reducing the power level. This new, third edition emphasizes novel calibration concepts, the specific requirements of new systems, the consequences of 22-nm technology and the need for a more statistical approach to accuracy. Pedagogical enhancements to this edition include additional, new exercises, solved examples to introduce all key, new concepts and warnings, remarks and hints, from a practitioner’s perspective, wherever appropriate. Considerable background information and practical tips, from designing a PCB, to lay-o...

  19. A digital to analog converter

    OpenAIRE

    Westra, Jan R.; Annema, Anne J.

    2000-01-01

    A digital to analog converter for a multibit digital input signal has a set of conversion elements for the positive signal excursions and a set of conversion elements for the negative signal excursions. In each set the conversion elements are selected according to a dynamic element matching algorithm. To improve the mismatch-noise shaping of these algorithms, excess conversion elements may be additionally selected.

  20. Electrostatic analogy for symmetron gravity

    Science.gov (United States)

    Ogden, Lillie; Brown, Katherine; Mathur, Harsh; Rovelli, Kevin

    2017-12-01

    The symmetron model is a scalar-tensor theory of gravity with a screening mechanism that suppresses the effect of the symmetron field at high densities characteristic of the Solar System and laboratory scales but allows it to act with gravitational strength at low density on the cosmological scale. We elucidate the screening mechanism by showing that in the quasistatic Newtonian limit there are precise analogies between symmetron gravity and electrostatics for both strong and weak screening. For strong screening we find that large dense bodies behave in a manner analogous to perfect conductors in electrostatics. Based on this analogy we find that the symmetron field exhibits a lightning rod effect wherein the field gradients are enhanced near the ends of pointed or elongated objects. An ellipsoid placed in a uniform symmetron gradient is shown to experience a torque. By symmetry there is no gravitational torque in this case. Hence this effect unmasks the symmetron and might serve as the basis for future laboratory experiments. The symmetron force between a point mass and a large dense body includes a component corresponding to the interaction of the point mass with its image in the larger body. None of these effects have counterparts in the Newtonian limit of Einstein gravity. We discuss the similarities between symmetron gravity and the chameleon model as well as the differences between the two.

  1. Third order digital-to-analog converter

    Science.gov (United States)

    Dotson, W. P.

    1972-01-01

    System, consisting of sample and hold digital-to-analog converter, clock circuit, sample delay circuit, initial condition circuit and interpolator circuit, improves accuracy of reconstructed analog signal without increasing sample rates.

  2. Hegel, Analogy, and Extraterrestrial Life

    Science.gov (United States)

    Ross, Joseph T.

    Georg Wilhelm Friedrich Hegel rejected the possibility of life outside of the Earth, according to several scholars of extraterrestrial life. Their position is that the solar system and specifically the planet Earth is the unique place in the cosmos where life, intelligence, and rationality can be. The present study offers a very different interpretation of Hegel's statements about the place of life on Earth by suggesting that, although Hegel did not believe that there were other solar systems where rationality is present, he did in fact suggest that planets in general, not the Earth exclusively, have life and possibly also intelligent inhabitants. Analogical syllogisms are superficial, according to Hegel, insofar as they try to conclude that there is life on the Moon even though there is no evidence of water or air on that body. Similar analogical arguments for life on the Sun made by Johann Elert Bode and William Herschel were considered by Hegel to be equally superficial. Analogical arguments were also used by astronomers and philosophers to suggest that life could be found on other planets in our solar system. Hegel offers no critique of analogical arguments for life on other planets, and in fact Hegel believed that life would be found on other planets. Planets, after all, have meteorological processes and therefore are "living" according to his philosophical account, unlike the Moon, Sun, and comets. Whereas William Herschel was already finding great similarities between the Sun and the stars and had extended these similarities to the property of having planets or being themselves inhabitable worlds, Hegel rejected this analogy. The Sun and stars have some properties in common, but for Hegel one cannot conclude from these similarities to the necessity that stars have planets. Hegel's arguments against the presence of life in the solar system were not directed against other planets, but rather against the Sun and Moon, both of which he said have a different

  3. Design and Analysis of Reconfigurable Analog System

    Science.gov (United States)

    2011-02-01

    NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT A highly...2008/12/12/31e83bac-500f-4182- acca -4d360295fd9c.pdf, Analog Devices, Analog Dialogue 39-06, June 2005. [15] D. A. Johns, K. Martin "Analog Integrated

  4. Analogies and the 5E Model

    Science.gov (United States)

    Orgill, Mary Kay; Thomas, Megan

    2007-01-01

    Science classes are full of abstract or challenging concepts that are easier to understand if an analogy is used to illustrate the points. Effective analogies motivate students, clarify students' thinking, help students overcome misconceptions, and give students ways to visualize abstract concepts. When they are used appropriately, analogies can…

  5. The Pulley Analogy Does Not Work for Every Siphon

    Science.gov (United States)

    Planinsic, Gorazd; Slisko, Josip

    2010-01-01

    How do siphons work? Some see atmospheric pressure, explicitly or implicitly, as a crucial factor in siphon action. Others explain that a siphon works due to a difference of water weights in unequal arms. According to the latter view, siphon action is analogous to the action of a pulley or to the behaviour of a chain that is moving over a tube. In…

  6. Analog circuit design art, science, and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    Analog Circuit Design: Art, Science, and Personalities discusses the many approaches and styles in the practice of analog circuit design. The book is written in an informal yet informative manner, making it easily understandable to those new in the field. The selection covers the definition, history, current practice, and future direction of analog design; the practice proper; and the styles in analog circuit design. The book also includes the problems usually encountered in analog circuit design; approach to feedback loop design; and other different techniques and applications. The text is

  7. Analog and mixed-signal electronics

    CERN Document Server

    Stephan, Karl

    2015-01-01

    A practical guide to analog and mixed-signal electronics, with an emphasis on design problems and applications This book provides an in-depth coverage of essential analog and mixed-signal topics such as power amplifiers, active filters, noise and dynamic range, analog-to-digital and digital-to-analog conversion techniques, phase-locked loops, and switching power supplies. Readers will learn the basics of linear systems, types of nonlinearities and their effects, op-amp circuits, the high-gain analog filter-amplifier, and signal generation. The author uses system design examples to motivate

  8. Practical analog electronics for technicians

    CERN Document Server

    Kimber, W A

    2013-01-01

    'Practical Analog Electronics for Technicians' not only provides an accessible introduction to electronics, but also supplies all the problems and practical activities needed to gain hands-on knowledge and experience. This emphasis on practice is surprisingly unusual in electronics texts, and has already gained Will Kimber popularity through the companion volume, 'Practical Digital Electronics for Technicians'. Written to cover the Advanced GNVQ optional unit in electronics, this book is also ideal for BTEC National, A-level electronics and City & Guilds courses. Together with 'Practical Digit

  9. Analog-to-digital conversion

    CERN Document Server

    Pelgrom, Marcel J. M

    2013-01-01

    This textbook is appropriate for use in graduate-level curricula in analog to digital conversion, as well as for practicing engineers in need of a state-of-the-art reference on data converters.  It discusses various analog-to-digital conversion principles, including sampling, quantization, reference generation, nyquist architectures and sigma-delta modulation.  This book presents an overview of the state-of-the-art in this field and focuses on issues of optimizing accuracy and speed, while reducing the power level. This new, second edition emphasizes novel calibration concepts, the specific requirements of new systems, the consequences of 45-nm technology and the need for a more statistical approach to accuracy.  Pedagogical enhancements to this edition include more than twice the exercises available in the first edition, solved examples to introduce all key, new concepts and warnings, remarks and hints, from a practitioner’s perspective, wherever appropriate.  Considerable background information and pr...

  10. Reliability of analog quantum simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sarovar, Mohan [Sandia National Laboratories, Digital and Quantum Information Systems, Livermore, CA (United States); Zhang, Jun; Zeng, Lishan [Shanghai Jiao Tong University, Joint Institute of UMich-SJTU, Key Laboratory of System Control and Information Processing (MOE), Shanghai (China)

    2017-12-15

    Analog quantum simulators (AQS) will likely be the first nontrivial application of quantum technology for predictive simulation. However, there remain questions regarding the degree of confidence that can be placed in the results of AQS since they do not naturally incorporate error correction. Specifically, how do we know whether an analog simulation of a quantum model will produce predictions that agree with the ideal model in the presence of inevitable imperfections? At the same time there is a widely held expectation that certain quantum simulation questions will be robust to errors and perturbations in the underlying hardware. Resolving these two points of view is a critical step in making the most of this promising technology. In this work we formalize the notion of AQS reliability by determining sensitivity of AQS outputs to underlying parameters, and formulate conditions for robust simulation. Our approach naturally reveals the importance of model symmetries in dictating the robust properties. To demonstrate the approach, we characterize the robust features of a variety of quantum many-body models. (orig.)

  11. Converging on a new role for analogy in problem solving and retrieval: when two problems are better than one

    National Research Council Canada - National Science Library

    Kurtz, Kenneth J; Loewenstein, Jeffrey

    2007-01-01

    .... In Experiment 1, comparison of test problems facilitated analogical problem solving. Experiment 2 showed that comparison is the critical factor since solving two test problems separately proved ineffective...

  12. Developmental and hormonally regulated messenger ribonucleic acid expression of KiSS-1 and its putative receptor, GPR54, in rat hypothalamus and potent luteinizing hormone-releasing activity of KiSS-1 peptide.

    Science.gov (United States)

    Navarro, V M; Castellano, J M; Fernández-Fernández, R; Barreiro, M L; Roa, J; Sanchez-Criado, J E; Aguilar, E; Dieguez, C; Pinilla, L; Tena-Sempere, M

    2004-10-01

    The gonadotropic axis is centrally controlled by a complex regulatory network of excitatory and inhibitory signals that is activated at puberty. Recently, loss of function mutations of the gene encoding G protein-coupled receptor 54 (GPR54), the putative receptor for the KiSS-1-derived peptide metastin, have been associated with lack of puberty onset and hypogonadotropic hypogonadism. Yet the pattern of expression and functional role of the KiSS-1/GPR54 system in the rat hypothalamus remain unexplored to date. In the present work, expression analyses of KiSS-1 and GPR54 genes were conducted in different physiological and experimental settings, and the effects of central administration of KiSS-1 peptide on LH release were assessed in vivo. Persistent expression of KiSS-1 and GPR54 mRNAs was detected in rat hypothalamus throughout postnatal development, with maximum expression levels at puberty in both male and female rats. Hypothalamic expression of KiSS-1 and GPR54 genes changed throughout the estrous cycle and was significantly increased after gonadectomy, a rise that was prevented by sex steroid replacement both in males and females. Moreover, hypothalamic expression of the KiSS-1 gene was sensitive to neonatal imprinting by estrogen. From a functional standpoint, intracerebroventricular administration of KiSS-1 peptide induced a dramatic increase in serum LH levels in prepubertal male and female rats as well as in adult animals. In conclusion, we provide novel evidence of the developmental and hormonally regulated expression of KiSS-1 and GPR54 mRNAs in rat hypothalamus and the ability of KiSS-1 peptide to potently stimulate LH secretion in vivo. Our current data support the contention that the hypothalamic KiSS-1/GPR54 system is a pivotal factor in central regulation of the gonadotropic axis at puberty and in adulthood.

  13. The relationship of analogical distance to analogical function and preinventive structure: the case of engineering design.

    Science.gov (United States)

    Christensen, Bo T; Schunn, Christian D

    2007-01-01

    Analogy was studied in real-world engineering design, using the in vivo method. Analogizing was found to occur frequently, entailing a roughly equal amount of within- and between-domain analogies. In partial support for theories of unconscious plagiarism (Brown & Murphy, 1989; Marsh, Landau, & Hicks, 1996) and Ward's (1994) path-of-least-resistance model, it was found that the reference to exemplars (in the form of prototypes) significantly reduced the number of between-domain analogies between source and target, as compared with using sketches or no external representational systems. Analogy served three functions in relation to novel design concepts: identifying problems, solving problems, and explaining concepts. Problem identifying analogies were mainly within domain, explanatory analogies were mainly between domain, and problem-solving analogies were a mixture of within- and between-domain analogies.

  14. The Young Solar Analogs Project

    Science.gov (United States)

    Gray, Richard O.; Saken, J. M.; Corbally, C. J.; Seeds, M. F.; Morrison, S. S.

    2012-01-01

    We are carrying out a long-term project of measuring chromospheric activity and brightness variations in 31 young solar analogs (YSAs) using the Dark Sky Observatory (DSO -- Appalachian State University) 32-inch telescope and the G/M spectrograph. These YSAs are solar-type (spectral types F8 - K2) stars with ages ranging from 0.3 - 1.5 Gyr. The goal of this project is to gain better understanding of the magnetic activity of the early Sun, and especially how that activity may have impacted the development of life on the Earth. This project will also yield insights into the space environments experienced by young Earth analogs. We are currently in our 5th year of obtaining Ca II K & H chromospheric flux measurements, and are beginning to see signs of long-term activity cycles in a number of our stars. In addition, rotational modulation of the chromospheric fluxes is detectable in our data, and we have determined rotational periods for many of our stars. Short timescale increases in the K & H fluxes have been observed in a number of our stars; these events may be related to stellar flares. VATTSpec, a new moderate-resolution spectrograph on the 1.8-m Vatican Telescope in Arizona, has recently become involved with the project. This spectrograph will increase our ability to detect short-term changes in stellar activity on timescales of hours to minutes. We have been monitoring the program stars for one year in a multi-band photometric system consisting of Stromgren-v, and Johnson B, V, and R filters. We will soon add a narrow-band H-alpha filter to the system. Photometry is being carried out with a small piggy-back telescope on the 32-inch, but a robotic photometric telescope is currently being installed at DSO for this purpose. This project is supported by the National Science Foundation.

  15. Neural correlates of creativity in analogical reasoning.

    Science.gov (United States)

    Green, Adam E; Kraemer, David J M; Fugelsang, Jonathan A; Gray, Jeremy R; Dunbar, Kevin N

    2012-03-01

    Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key determinant of the creativity of analogical mapping (i.e., more distant analogies are generally more creative). Here, we used functional magnetic resonance imaging to assess brain activity during an analogy generation task in which we varied the semantic distance of analogical mapping (as derived quantitatively from a latent semantic analysis). Data indicated that activity within an a priori region of interest in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. Results implicate increased recruitment of frontopolar cortex as a mechanism for integrating semantically distant information to generate solutions in creative analogical reasoning. 2012 APA, all rights reserved

  16. Analog MOS integrated circuits for signal processing

    Science.gov (United States)

    Gregorian, R.; Temes, G. C.

    Theoretical and practical aspects of analog MOS integrated circuits are discussed. The basic properties of these circuits are described, providing necessary background material in mathematics and semiconductor device physics and technology. The operation and design of such important circuits as switched-capacitor filters, analog-to-digital and digital-to-analog converters, amplifiers, modulators, and oscillators. Practical problems encountered in design are discussed, solutions are provided, and some examples of actual system applications are given.

  17. contribution of growth hormone-releasing hormone and ...

    African Journals Online (AJOL)

    Side-effects. On occasion bolus IV doses of GHRH caused flushing and warmth of the face, transient tachycardia and a slight lowering of blood pressure. The administration of bromocriptine and atenolol in combination caused dizziness after the test in 2 elderly subjects, presumably due to hypotension. 0 adverse effects ...

  18. contribution of growth hormone-releasing hormone and ...

    African Journals Online (AJOL)

    The vertical dimension is stronger in target-driven programmes, the horizontal is stronger in. PHC. Vertical programmes may have a special place in certain phases of the fight against diseases, namely in the beginning to start up a programme and at the end to finish the job. To date, the world is still divided into horizontalists ...

  19. Measurements of Dielectric Properties of Mars Analog Soils with Variable Temperature and Moisture Content

    Science.gov (United States)

    Cereti, A.; Mellon, M. T.; Sizemore, H. G.; Phillips, R. J.

    2009-03-01

    We performed impedance spectroscopy of various martian analog soils, with varying temperature and moisture content, to investigate how the complex dielectric permittivity depends on these factors, as this parameter can strongly affect radar signals propagation.

  20. Novel Analog For Muscle Deconditioning

    Science.gov (United States)

    Ploutz-Snyder, Lori; Ryder, Jeff; Buxton, Roxanne; Redd. Elizabeth; Scott-Pandorf, Melissa; Hackney, Kyle; Fiedler, James; Ploutz-Snyder, Robert; Bloomberg, Jacob

    2011-01-01

    Existing models (such as bed rest) of muscle deconditioning are cumbersome and expensive. We propose a new model utilizing a weighted suit to manipulate strength, power, or endurance (function) relative to body weight (BW). Methods: 20 subjects performed 7 occupational astronaut tasks while wearing a suit weighted with 0-120% of BW. Models of the full relationship between muscle function/BW and task completion time were developed using fractional polynomial regression and verified by the addition of pre-and postflightastronaut performance data for the same tasks. Splineregression was used to identify muscle function thresholds below which task performance was impaired. Results: Thresholds of performance decline were identified for each task. Seated egress & walk (most difficult task) showed thresholds of leg press (LP) isometric peak force/BW of 18 N/kg, LP power/BW of 18 W/kg, LP work/BW of 79 J/kg, isokineticknee extension (KE)/BW of 6 Nm/kg, and KE torque/BW of 1.9 Nm/kg.Conclusions: Laboratory manipulation of relative strength has promise as an appropriate analog for spaceflight-induced loss of muscle function, for predicting occupational task performance and establishing operationally relevant strength thresholds.

  1. Analogies in biology textbooks in zoology teaching

    Directory of Open Access Journals (Sweden)

    Saulo Cézar Seiffert Santos

    2011-05-01

    Full Text Available The biologic structures of living creatures are of difficult understanding for students, because they are usually unknown by those, in needs of strategic didactics in order to facilitate the student understanding. There are several strategies and methods for teaching, such as, analogies, metaphors, descriptions, among others. In this article we aim to identify, assess and classify the analogies used in the Higher School Biology textbooks, commonly used in Public State Schools of Manaus – AM, related to the zoology theme. The methodological procedure includes: a analysis of the whole zoological content of the most used textbooks in the public state network of Amazonas throughout the year; b three didactic textbooks have been specifically analyzed in order to specify the class taxon of “Fish” for the comparison of possible variations of types and quantities of analogies. The adopted classification of analogies was of Curtis & Reigeluth (1984 and the model of enriching analysis was according to the TWA Glynn model (Harrison & Treagust, 1993. It has been concluded that the use of analogies is greater in the content of invertebrates than that of vertebrates. Most Analogies are presented in a simple and direct manner, comparing structures, concrete to concrete, and of verbal mediation, almost nothing is presented in a diverse and heuristic manner of Zoology content on the LD. The development of limits of comparison and reflexion about the analogies was rare, only the presentation of the analogue and the target of analogy occurred.

  2. The Use of Analogies in Written Text.

    Science.gov (United States)

    Curtis, Ruth V.; Reigeluth, Charles M.

    1984-01-01

    Describes a study that explored and inductively classified analogies in 26 science textbooks, ranging from elementary to postsecondary level, to provide a systematic description of the phenomenon and generate prescriptive principles for their use in instruction. Classification categories include analogical relationship, presentation format,…

  3. The Pennies-as-Electrons Analogy

    Science.gov (United States)

    Ashmann, Scott

    2009-01-01

    Everyday experiences familiarize students with the ways in which electricity is used, but often the underlying concepts remain a mystery. Teachers often use analogies to help students relate the flow of electrons to other common systems, but many times these analogies are incomplete and lead to more student misconceptions. However, the "pass the…

  4. An Analog Computer for Electronic Engineering Education

    Science.gov (United States)

    Fitch, A. L.; Iu, H. H. C.; Lu, D. D. C.

    2011-01-01

    This paper describes a compact analog computer and proposes its use in electronic engineering teaching laboratories to develop student understanding of applications in analog electronics, electronic components, engineering mathematics, control engineering, safe laboratory and workshop practices, circuit construction, testing, and maintenance. The…

  5. A Mechanical Analogy for the Photoelectric Effect

    Science.gov (United States)

    Kovacevic, Milan S.; Djordjevich, Alexandar

    2006-01-01

    Analogy is a potent tool in the teacher's repertoire. It has been particularly well recognized in the teaching of science. However, careful planning is required for its effective application to prevent documented drawbacks when analogies are stretched too far. Befitting the occasion of the World Year of Physics commemorating Albert Einstein's 1905…

  6. Children's Use of Analogy during Collaborative Reasoning

    Science.gov (United States)

    Lin, Tzu-Jung; Anderson, Richard C.; Hummel, John E.; Jadallah, May; Miller, Brian W.; Nguyen-Jahiel, Kim; Morris, Joshua A.; Kuo, Li-Jen; Kim, Il-Hee; Wu, Xiaoying; Dong, Ting

    2012-01-01

    This microgenetic study examined social influences on children's development of analogical reasoning during peer-led small-group discussions of stories about controversial issues. A total of 277 analogies were identified among 7,215 child turns for speaking during 54 discussions from 18 discussion groups in 6 fourth-grade classrooms (N = 120; age…

  7. HISTORIANS AND MIRACLES : THE PRINCIPLE OF ANALOGY ...

    African Journals Online (AJOL)

    2008-11-27

    Nov 27, 2008 ... can still establish scientifically that dinosaurs once existed, since their fossils remain. However, this is in spite of the principle of analogy and we may likewise be able to establish miracles historically if we have credible testimony that remains. The principle of analogy also appears to assume metaphysical.

  8. PEMETAAN ANALOGI PADA KONSEP ABSTRAK FISIKA

    Directory of Open Access Journals (Sweden)

    Nyoto Suseno

    2014-11-01

    Full Text Available The research of any where founded majority students have common difficulties in abstract physics concept. The result of observation, lecturers have problem  in teaching implementation of abstract concepts on physics learning. The objective of this research is to find out the ways how to overcome this problem. The research place of  physics education programs and senior high school. The data are colected by quetionere, observation and interview. The lecturer behavior to making out this case is use of analogy to make concrete a abstract concept. This action is true, because the analogies are dynamic tools that facilitate understanding, rather than representations of the correct and static explanations. Using analogies not only promoted profound understanding of abstract concept, but also helped students overcome their misconceptions. However used analogy in teaching not yet planed with seriousness, analogy used spontanously with the result that less optimal. By planing and selecting right analogy, the role of analogy can be achieved the optimal result. Therefore, it is important to maping analogies of abstract consepts on physics learning.

  9. Computational approaches to analogical reasoning current trends

    CERN Document Server

    Richard, Gilles

    2014-01-01

    Analogical reasoning is known as a powerful mode for drawing plausible conclusions and solving problems. It has been the topic of a huge number of works by philosophers, anthropologists, linguists, psychologists, and computer scientists. As such, it has been early studied in artificial intelligence, with a particular renewal of interest in the last decade. The present volume provides a structured view of current research trends on computational approaches to analogical reasoning. It starts with an overview of the field, with an extensive bibliography. The 14 collected contributions cover a large scope of issues. First, the use of analogical proportions and analogies is explained and discussed in various natural language processing problems, as well as in automated deduction. Then, different formal frameworks for handling analogies are presented, dealing with case-based reasoning, heuristic-driven theory projection, commonsense reasoning about incomplete rule bases, logical proportions induced by similarity an...

  10. Inhibition of Delta-induced Notch signaling using fucose analogs.

    Science.gov (United States)

    Schneider, Michael; Kumar, Vivek; Nordstrøm, Lars Ulrik; Feng, Lei; Takeuchi, Hideyuki; Hao, Huilin; Luca, Vincent C; Garcia, K Christopher; Stanley, Pamela; Wu, Peng; Haltiwanger, Robert S

    2018-01-01

    Notch is a cell-surface receptor that controls cell-fate decisions and is regulated by O-glycans attached to epidermal growth factor-like (EGF) repeats in its extracellular domain. Protein O-fucosyltransferase 1 (Pofut1) modifies EGF repeats with O-fucose and is essential for Notch signaling. Constitutive activation of Notch signaling has been associated with a variety of human malignancies. Therefore, tools that inhibit Notch activity are being developed as cancer therapeutics. To this end, we screened L-fucose analogs for their effects on Notch signaling. Two analogs, 6-alkynyl and 6-alkenyl fucose, were substrates of Pofut1 and were incorporated directly into Notch EGF repeats in cells. Both analogs were potent inhibitors of binding to and activation of Notch1 by Notch ligands Dll1 and Dll4, but not by Jag1. Mutagenesis and modeling studies suggest that incorporation of the analogs into EGF8 of Notch1 markedly reduces the ability of Delta ligands to bind and activate Notch1.

  11. ON THE FREQUENCY OF POTENTIAL VENUS ANALOGS FROM KEPLER DATA

    Energy Technology Data Exchange (ETDEWEB)

    Kane, Stephen R. [Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States); Kopparapu, Ravi Kumar [Department of Geosciences, Penn State University, 443 Deike Building, University Park, PA 16802 (United States); Domagal-Goldman, Shawn D., E-mail: skane@sfsu.edu [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2014-10-10

    The field of exoplanetary science has seen a dramatic improvement in sensitivity to terrestrial planets over recent years. Such discoveries have been a key feature of results from the Kepler mission which utilizes the transit method to determine the size of the planet. These discoveries have resulted in a corresponding interest in the topic of the Habitable Zone and the search for potential Earth analogs. Within the solar system, there is a clear dichotomy between Venus and Earth in terms of atmospheric evolution, likely the result of the large difference (approximately a factor of two) in incident flux from the Sun. Since Venus is 95% of the Earth's radius in size, it is impossible to distinguish between these two planets based only on size. In this Letter we discuss planetary insolation in the context of atmospheric erosion and runaway greenhouse limits for planets similar to Venus. We define a ''Venus Zone'' in which the planet is more likely to be a Venus analog rather than an Earth analog. We identify 43 potential Venus analogs with an occurrence rate (η{sub ♀}) of 0.32{sub −0.07}{sup +0.05} and 0.45{sub −0.09}{sup +0.06} for M dwarfs and GK dwarfs, respectively.

  12. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.

    OpenAIRE

    Godek, C P; Cynamon, M H

    1990-01-01

    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs...

  13. Structural Perspectives of Insulin Receptor Isoform-Selective Insulin Analogs

    Czech Academy of Sciences Publication Activity Database

    Jiráček, Jiří; Žáková, Lenka

    2017-01-01

    Roč. 8, Jul 27 (2017), č. článku 167. ISSN 1664-2392 R&D Projects: GA ČR GA15-19018S Institutional support: RVO:61388963 Keywords : insulin receptor * insulin binding * analog * diabetes * glucose Subject RIV: CE - Biochemistry Impact factor: 3.675, year: 2016 http:// journal .frontiersin.org/article/10.3389/fendo.2017.00167/full

  14. Advances in Analog Circuit Design 2015

    CERN Document Server

    Baschirotto, Andrea; Harpe, Pieter

    2016-01-01

    This book is based on the 18 tutorials presented during the 24th workshop on Advances in Analog Circuit Design. Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including low-power and energy-efficient analog electronics, with specific contributions focusing on the design of efficient sensor interfaces and low-power RF systems. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development. ·         Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; ·         Presents material in a tutorial-based format; ·         Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing.

  15. Analogies: Explanatory Tools in Web-Based Science Instruction

    Science.gov (United States)

    Glynn, Shawn M.; Taasoobshirazi, Gita; Fowler, Shawn

    2007-01-01

    This article helps designers of Web-based science instruction construct analogies that are as effective as those used in classrooms by exemplary science teachers. First, the authors explain what analogies are, how analogies foster learning, and what form analogies should take. Second, they discuss science teachers' use of analogies. Third, they…

  16. The MARS2013 Mars analog mission.

    Science.gov (United States)

    Groemer, Gernot; Soucek, Alexander; Frischauf, Norbert; Stumptner, Willibald; Ragonig, Christoph; Sams, Sebastian; Bartenstein, Thomas; Häuplik-Meusburger, Sandra; Petrova, Polina; Evetts, Simon; Sivenesan, Chan; Bothe, Claudia; Boyd, Andrea; Dinkelaker, Aline; Dissertori, Markus; Fasching, David; Fischer, Monika; Föger, Daniel; Foresta, Luca; Fritsch, Lukas; Fuchs, Harald; Gautsch, Christoph; Gerard, Stephan; Goetzloff, Linda; Gołebiowska, Izabella; Gorur, Paavan; Groemer, Gerhard; Groll, Petra; Haider, Christian; Haider, Olivia; Hauth, Eva; Hauth, Stefan; Hettrich, Sebastian; Jais, Wolfgang; Jones, Natalie; Taj-Eddine, Kamal; Karl, Alexander; Kauerhoff, Tilo; Khan, Muhammad Shadab; Kjeldsen, Andreas; Klauck, Jan; Losiak, Anna; Luger, Markus; Luger, Thomas; Luger, Ulrich; McArthur, Jane; Moser, Linda; Neuner, Julia; Orgel, Csilla; Ori, Gian Gabriele; Paternesi, Roberta; Peschier, Jarno; Pfeil, Isabella; Prock, Silvia; Radinger, Josef; Ramirez, Barbara; Ramo, Wissam; Rampey, Mike; Sams, Arnold; Sams, Elisabeth; Sandu, Oana; Sans, Alejandra; Sansone, Petra; Scheer, Daniela; Schildhammer, Daniel; Scornet, Quentin; Sejkora, Nina; Stadler, Andrea; Stummer, Florian; Taraba, Michael; Tlustos, Reinhard; Toferer, Ernst; Turetschek, Thomas; Winter, Egon; Zanella-Kux, Katja

    2014-05-01

    We report on the MARS2013 mission, a 4-week Mars analog field test in the northern Sahara. Nineteen experiments were conducted by a field crew in Morocco under simulated martian surface exploration conditions, supervised by a Mission Support Center in Innsbruck, Austria. A Remote Science Support team analyzed field data in near real time, providing planning input for the management of a complex system of field assets; two advanced space suit simulators, four robotic vehicles, an emergency shelter, and a stationary sensor platform in a realistic work flow were coordinated by a Flight Control Team. A dedicated flight planning group, external control centers for rover tele-operations, and a biomedical monitoring team supported the field operations. A 10 min satellite communication delay and other limitations pertinent to human planetary surface activities were introduced. The fields of research for the experiments were geology, human factors, astrobiology, robotics, tele-science, exploration, and operations research. This paper provides an overview of the geological context and environmental conditions of the test site and the mission architecture, in particular the communication infrastructure emulating the signal travel time between Earth and Mars. We report on the operational work flows and the experiments conducted, including a deployable shelter prototype for multiple-day extravehicular activities and contingency situations.

  17. Programmable Analog-To-Digital Converter

    Science.gov (United States)

    Kist, Edward H., Jr.

    1993-01-01

    High-speed analog-to-digital converter with programmable voltage steps that can be changed during operation. Allows concentration of converter resolution over specific portion of waveform. Particularly useful in digitizing wind-shear radar and lidar return signals, in digital oscilloscopes, and other applications in which desirable to increase digital resolution over specific area of waveform while accepting lower resolution over rest of waveform. Effective increase in dynamic range achieved without increase in number of analog-to-digital converter bits. Enabling faster analog-to-digital conversion.

  18. Identifying Solar Analogs in the Kepler Field

    Science.gov (United States)

    Buzasi, Derek L.; Lezcano, Andrew; Preston, Heather L.

    2014-06-01

    Since human beings live on a planet orbiting a G2 V star, to us perhaps the most intrinsically interesting category of stars about which planets have been discovered is solar analogs. While Kepler has observed more than 26000 targets which have effective temperatures within 100K of the Sun, many of these are not true solar analogs due to activity, surface gravity, metallicity, or other considerations. Here we combine ground-based measurements of effective temperature and metallicity with data on rotational periods and surface gravities derived from 16 quarters of Kepler observations to produce a near-complete sample of solar analogs in the Kepler field. We then compare the statistical distribution of stellar physical parameters, including activity level, for subsets of solar analogs consisting of KOIs and those with no detected exoplanets. Finally, we produce a list of potential solar twins in the Kepler field.

  19. Photonic Analog-to-Digital Conversion Technology

    National Research Council Canada - National Science Library

    Ng, W; Lu, L; Yap, D; Bridges, W; Mokhtari, M

    2004-01-01

    This report documents the work undertaken by HRL Laboratories, LLC and its subcontractors, California Institute of Technology and Raytheon Electronics Systems, on the development of multi-GHz photonic analog-to-digital (A/D...

  20. Analogical scaffolding and the learning of abstract ideas in physics: Empirical studies

    Science.gov (United States)

    Podolefsky, Noah S.; Finkelstein, Noah D.

    2007-12-01

    Previously, we proposed a model of student reasoning which combines the roles of representation, analogy, and layering of meaning—analogical scaffolding [Podolefsky and Finkelstein, Phys. Rev. ST Phys. Educ. Res. 3, 010109 (2007)]. The present empirical studies build on this model to examine its utility and demonstrate the vital intertwining of representation, analogy, and conceptual learning in physics. In two studies of student reasoning using analogy, we show that representations couple to students’ existing prior knowledge and also lead to the dynamic formation of new knowledge. Students presented with abstract, concrete, or blended (both abstract and concrete) representations produced markedly different response patterns. In the first study, using analogies to scaffold understanding of electromagnetic (EM) waves, students in the blend group were more likely to reason productively about EM waves than students in the abstract group by as much as a factor of 3 (73% vs 24% correct, p=0.002 ). In the second study, examining representation use within one domain (sound waves), the blend group was more likely to reason productively about sound waves than the abstract group by as much as a factor of 2 (48% vs 23% correct, p=0.002 ). Using the analogical scaffolding model we examine when and why students succeed and fail to use analogies and interpret representations appropriately.

  1. Analogical scaffolding and the learning of abstract ideas in physics: Empirical studies

    Directory of Open Access Journals (Sweden)

    Noah D. Finkelstein

    2007-09-01

    Full Text Available Previously, we proposed a model of student reasoning which combines the roles of representation, analogy, and layering of meaning—analogical scaffolding [Podolefsky and Finkelstein, Phys. Rev. ST Phys. Educ. Res. 3, 010109 (2007]. The present empirical studies build on this model to examine its utility and demonstrate the vital intertwining of representation, analogy, and conceptual learning in physics. In two studies of student reasoning using analogy, we show that representations couple to students’ existing prior knowledge and also lead to the dynamic formation of new knowledge. Students presented with abstract, concrete, or blended (both abstract and concrete representations produced markedly different response patterns. In the first study, using analogies to scaffold understanding of electromagnetic (EM waves, students in the blend group were more likely to reason productively about EM waves than students in the abstract group by as much as a factor of 3 (73% vs 24% correct, p=0.002 . In the second study, examining representation use within one domain (sound waves, the blend group was more likely to reason productively about sound waves than the abstract group by as much as a factor of 2 (48% vs 23% correct, p=0.002 . Using the analogical scaffolding model we examine when and why students succeed and fail to use analogies and interpret representations appropriately.

  2. ANALOG-TO-DIGITAL DATA CONVERTER

    Science.gov (United States)

    Rodgers, G.W.; Althouse, J.E.; Anderson, D.P.; Bussey, G.R.; Minnear, L.H.

    1960-09-01

    Electrical apparatus is described, particularly useful in telemetry work, for converting analog signals into electrical pulses and recording them. An electronic editor commands the taking of signal readings at a frequency which varies according to linearity of the analog signal being converted. Readings of information signals are recorded, along with time base readings and serial numbering, if desired, on magnetic tape and the latter may be used to operate a computer or the like. Magnetic tape data may be transferred to punched cards.

  3. High-frequency analog integrated circuit design

    CERN Document Server

    1995-01-01

    To learn more about designing analog integrated circuits (ICs) at microwave frequencies using GaAs materials, turn to this text and reference. It addresses GaAs MESFET-based IC processing. Describes the newfound ability to apply silicon analog design techniques to reliable GaAs materials and devices which, until now, was only available through technical papers scattered throughout hundred of articles in dozens of professional journals.

  4. Analog modelling of obduction processes

    Science.gov (United States)

    Agard, P.; Zuo, X.; Funiciello, F.; Bellahsen, N.; Faccenna, C.; Savva, D.

    2012-04-01

    Obduction corresponds to one of plate tectonics oddities, whereby dense, oceanic rocks (ophiolites) are presumably 'thrust' on top of light, continental ones, as for the short-lived, almost synchronous Peri-Arabic obduction (which took place along thousands of km from Turkey to Oman in c. 5-10 Ma). Analog modelling experiments were performed to study the mechanisms of obduction initiation and test various triggering hypotheses (i.e., plate acceleration, slab hitting the 660 km discontinuity, ridge subduction; Agard et al., 2007). The experimental setup comprises (1) an upper mantle, modelled as a low-viscosity transparent Newtonian glucose syrup filling a rigid Plexiglas tank and (2) high-viscosity silicone plates (Rhodrosil Gomme with PDMS iron fillers to reproduce densities of continental or oceanic plates), located at the centre of the tank above the syrup to simulate the subducting and the overriding plates - and avoid friction on the sides of the tank. Convergence is simulated by pushing on a piston at one end of the model with velocities comparable to those of plate tectonics (i.e., in the range 1-10 cm/yr). The reference set-up includes, from one end to the other (~60 cm): (i) the piston, (ii) a continental margin containing a transition zone to the adjacent oceanic plate, (iii) a weakness zone with variable resistance and dip (W), (iv) an oceanic plate - with or without a spreading ridge, (v) a subduction zone (S) dipping away from the piston and (vi) an upper, active continental margin, below which the oceanic plate is being subducted at the start of the experiment (as is known to have been the case in Oman). Several configurations were tested and over thirty different parametric tests were performed. Special emphasis was placed on comparing different types of weakness zone (W) and the extent of mechanical coupling across them, particularly when plates were accelerated. Displacements, together with along-strike and across-strike internal deformation in all

  5. An analogical approach to grammaticalization

    NARCIS (Netherlands)

    Fischer, O.; Stathi, K.; Gehweiler, E.; König, E.

    2010-01-01

    Two well-known approaches to language change illustrate a fundamental difference between functional and formal linguistics as to what are considered important mechanisms in change. In Grammaticalization, emphasis is on the semantic-pragmatic factors guiding change, while Generative Theory

  6. Ultra-high-speed optical transmission using digital-preprocessed analog-multiplexed DAC

    Science.gov (United States)

    Yamazaki, Hiroshi; Nagatani, Munehiko; Hamaoka, Fukutaro; Horikoshi, Kengo; Nakamura, Masanori; Matsushita, Asuka; Kanazawa, Shigeru; Hashimoto, Toshikazu; Nosaka, Hideyuki; Miyamoto, Yutaka

    2018-02-01

    In advanced fiber transmission systems with digital signal processors (DSPs), analog bandwidths of digital-to-analog converters (DACs), which interface the DSPs and optics, are the major factors limiting the data rates. We have developed a technology to extend the DACs' bandwidth using a digital preprocessor, two sub-DACs, and an analog multiplexer. This technology enables us to generate baseband signals with bandwidths of up to around 60 GHz, which is almost twice that of signals generated by typical CMOS DACs. In this paper, we describe the principle of the bandwidth extension and review high-speed transmission experiments enabled by this technology.

  7. Optical domain analog to digital conversion methods and apparatus

    Science.gov (United States)

    Vawter, Gregory A

    2014-05-13

    Methods and apparatus for optical analog to digital conversion are disclosed. An optical signal is converted by mapping the optical analog signal onto a wavelength modulated optical beam, passing the mapped beam through interferometers to generate analog bit representation signals, and converting the analog bit representation signals into an optical digital signal. A photodiode receives an optical analog signal, a wavelength modulated laser coupled to the photodiode maps the optical analog signal to a wavelength modulated optical beam, interferometers produce an analog bit representation signal from the mapped wavelength modulated optical beam, and sample and threshold circuits corresponding to the interferometers produce a digital bit signal from the analog bit representation signal.

  8. Digital Analog Design: A Highly-Efficient Method to Design Analog Circuits

    Science.gov (United States)

    2017-03-01

    Digital Analog Design: A Highly-Efficient Method to Design Analog Circuits* Mark Horowitz and Byong Lim Department of Electrical Engineering...Stanford University Stanford, CA, 940305 Abstract: The past 30 years have seen an enormous growth in the power and sophistication of digital ...design tools, while progress in analog tools has been much more modest. Digital tools use many abstractions to allow them to validate

  9. Analog Signal Correlating Using an Analog-Based Signal Conditioning Front End

    Science.gov (United States)

    Prokop, Norman; Krasowski, Michael

    2013-01-01

    This innovation is capable of correlating two analog signals by using an analog-based signal conditioning front end to hard-limit the analog signals through adaptive thresholding into a binary bit stream, then performing the correlation using a Hamming "similarity" calculator function embedded in a one-bit digital correlator (OBDC). By converting the analog signal into a bit stream, the calculation of the correlation function is simplified, and less hardware resources are needed. This binary representation allows the hardware to move from a DSP where instructions are performed serially, into digital logic where calculations can be performed in parallel, greatly speeding up calculations.

  10. Anti-Plasmodium activity of ceramide analogs

    Directory of Open Access Journals (Sweden)

    Gatt Shimon

    2004-12-01

    Full Text Available Abstract Background Sphingolipids are key molecules regulating many essential functions in eukaryotic cells and ceramide plays a central role in sphingolipid metabolism. A sphingolipid metabolism occurs in the intraerythrocytic stages of Plasmodium falciparum and is associated with essential biological processes. It constitutes an attractive and potential target for the development of new antimalarial drugs. Methods The anti-Plasmodium activity of a series of ceramide analogs containing different linkages (amide, methylene or thiourea linkages between the fatty acid part of ceramide and the sphingoid core was investigated in culture and compared to the sphingolipid analog PPMP (d,1-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol. This analog is known to inhibit the parasite sphingomyelin synthase activity and block parasite development by preventing the formation of the tubovesicular network that extends from the parasitophorous vacuole to the red cell membrane and delivers essential extracellular nutrients to the parasite. Results Analogs containing methylene linkage showed a considerably higher anti-Plasmodium activity (IC50 in the low nanomolar range than PPMP and their counterparts with a natural amide linkage (IC50 in the micromolar range. The methylene analogs blocked irreversibly P. falciparum development leading to parasite eradication in contrast to PPMP whose effect is cytostatic. A high sensitivity of action towards the parasite was observed when compared to their effect on the human MRC-5 cell growth. The toxicity towards parasites did not correlate with the inhibition by methylene analogs of the parasite sphingomyelin synthase activity and the tubovesicular network formation, indicating that this enzyme is not their primary target. Conclusions It has been shown that ceramide analogs were potent inhibitors of P. falciparum growth in culture. Interestingly, the nature of the linkage between the fatty acid part and the

  11. Neurotoxic Alkaloids: Saxitoxin and Its Analogs

    Directory of Open Access Journals (Sweden)

    Troco K. Mihali

    2010-07-01

    Full Text Available Saxitoxin (STX and its 57 analogs are a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs. PSTs are the causative agents of paralytic shellfish poisoning (PSP and are mostly associated with marine dinoflagellates (eukaryotes and freshwater cyanobacteria (prokaryotes, which form extensive blooms around the world. PST producing dinoflagellates belong to the genera Alexandrium, Gymnodinium and Pyrodinium whilst production has been identified in several cyanobacterial genera including Anabaena, Cylindrospermopsis, Aphanizomenon Planktothrix and Lyngbya. STX and its analogs can be structurally classified into several classes such as non-sulfated, mono-sulfated, di-sulfated, decarbamoylated and the recently discovered hydrophobic analogs—each with varying levels of toxicity. Biotransformation of the PSTs into other PST analogs has been identified within marine invertebrates, humans and bacteria. An improved understanding of PST transformation into less toxic analogs and degradation, both chemically or enzymatically, will be important for the development of methods for the detoxification of contaminated water supplies and of shellfish destined for consumption. Some PSTs also have demonstrated pharmaceutical potential as a long-term anesthetic in the treatment of anal fissures and for chronic tension-type headache. The recent elucidation of the saxitoxin biosynthetic gene cluster in cyanobacteria and the identification of new PST analogs will present opportunities to further explore the pharmaceutical potential of these intriguing alkaloids.

  12. NaturAnalogs for the Unsaturated Zone

    Energy Technology Data Exchange (ETDEWEB)

    A. Simmons; A. Unger; M. Murrell

    2000-03-08

    The purpose of this Analysis/Model Report (AMR) is to document natural and anthropogenic (human-induced) analog sites and processes that are applicable to flow and transport processes expected to occur at the potential Yucca Mountain repository in order to build increased confidence in modeling processes of Unsaturated Zone (UZ) flow and transport. This AMR was prepared in accordance with ''AMR Development Plan for U0135, Natural Analogs for the UZ'' (CRWMS 1999a). Knowledge from analog sites and processes is used as corroborating information to test and build confidence in flow and transport models of Yucca Mountain, Nevada. This AMR supports the Unsaturated Zone (UZ) Flow and Transport Process Model Report (PMR) and the Yucca Mountain Site Description. The objectives of this AMR are to test and build confidence in the representation of UZ processes in numerical models utilized in the UZ Flow and Transport Model. This is accomplished by: (1) applying data from Boxy Canyon, Idaho in simulations of UZ flow using the same methodologies incorporated in the Yucca Mountain UZ Flow and Transport Model to assess the fracture-matrix interaction conceptual model; (2) Providing a preliminary basis for analysis of radionuclide transport at Pena Blanca, Mexico as an analog of radionuclide transport at Yucca Mountain; and (3) Synthesizing existing information from natural analog studies to provide corroborating evidence for representation of ambient and thermally coupled UZ flow and transport processes in the UZ Model.

  13. Not All Analogies Are Created Equal: Associative and Categorical Analogy Processing following Brain Damage

    Science.gov (United States)

    Schmidt, Gwenda L.; Cardillo, Eileen R.; Kranjec, Alexander; Lehet, Matthew; Widick, Page; Chatterjee, Anjan

    2012-01-01

    Current research on analogy processing assumes that different conceptual relations are treated similarly. However, just as words and concepts are related in distinct ways, different kinds of analogies may employ distinct types of relationships. An important distinction in how words are related is the difference between associative (dog-bone) and…

  14. The Effect of Analogy-Based Teaching on Students' Achievement and Students' Views about Analogies

    Science.gov (United States)

    Genc, Murat

    2013-01-01

    The purpose of this study is to determine the effect of the analogy-based teaching on students' achievement and students' views about analogies. In this research, Solomon group design which is one of the experimental designs, was implemented. The sample of the research consists of 108 students in four 6th grade classes in Turkey. The achievement…

  15. Xampling: Compressed Sensing of Analog Signals

    CERN Document Server

    Mishali, Moshe

    2011-01-01

    Xampling generalizes compressed sensing (CS) to reduced-rate sampling of analog signals. A unified framework is introduced for low rate sampling and processing of signals lying in a union of subspaces. Xampling consists of two main blocks: Analog compression that narrows down the input bandwidth prior to sampling with commercial devices followed by a nonlinear algorithm that detects the input subspace prior to conventional signal processing. A variety of analog CS applications are reviewed within the unified Xampling framework including a general filter-bank scheme for sparse shift-invariant spaces, periodic nonuniform sampling and modulated wideband conversion for multiband communications with unknown carrier frequencies, acquisition techniques for finite rate of innovation signals with applications to medical and radar imaging, and random demodulation of sparse harmonic tones. A hardware-oriented viewpoint is advocated throughout, addressing practical constraints and exemplifying hardware realizations where...

  16. Formal analogies in physics teacher education

    DEFF Research Database (Denmark)

    Avelar Sotomaior Karam, Ricardo; Ricardo, Elio

    2012-01-01

    Reasoning by similarities, especially the ones associated with formal aspects, is one of the most valuable sources for the development of physical theories. The essential role of formal analogies in science can be highlighted by the fact that several equations for different physical situations have...... the exact same appearance. Coulomb’s law’s similarity with Newton’s, Maxwell’s application of fluid theory to electromagnetism and Hamilton’s optical mechanical analogy are some among many other examples. These cases illustrate the power of mathematics in providing unifying structures for physics. Despite...... the relevance of the subject, formal analogies are rarely systematically approached in physics education. In order to discuss this issue with pre-service physics teachers, we planned a lecture and designed a questionnaire with the goal of encouraging them to think about some “coincidences” in well known...

  17. Electronic devices for analog signal processing

    CERN Document Server

    Rybin, Yu K

    2012-01-01

    Electronic Devices for Analog Signal Processing is intended for engineers and post graduates and considers electronic devices applied to process analog signals in instrument making, automation, measurements, and other branches of technology. They perform various transformations of electrical signals: scaling, integration, logarithming, etc. The need in their deeper study is caused, on the one hand, by the extension of the forms of the input signal and increasing accuracy and performance of such devices, and on the other hand, new devices constantly emerge and are already widely used in practice, but no information about them are written in books on electronics. The basic approach of presenting the material in Electronic Devices for Analog Signal Processing can be formulated as follows: the study with help from self-education. While divided into seven chapters, each chapter contains theoretical material, examples of practical problems, questions and tests. The most difficult questions are marked by a diamon...

  18. Landauer Bound for Analog Computing Systems

    CERN Document Server

    Diamantini, M. Cristina; Trugenberger, Carlo A.

    2016-01-01

    By establishing a relation between information erasure and continuous phase transitions we generalise the Landauer bound to analog computing systems. The entropy production per degree of freedom during erasure of an analog variable (reset to standard value) is given by the logarithm of the configurational volume measured in units of its minimal quantum. As a consequence every computation has to be carried on with a finite number of bits and infinite precision is forbidden by the fundamental laws of physics, since it would require an infinite amount of energy.

  19. Design of analog integrated circuits and systems

    CERN Document Server

    Laker, Kenneth R

    1994-01-01

    This text is designed for senior or graduate level courses in analog integrated circuits or design of analog integrated circuits. This book combines consideration of CMOS and bipolar circuits into a unified treatment. Also included are CMOS-bipolar circuits made possible by BiCMOS technology. The text progresses from MOS and bipolar device modelling to simple one and two transistor building block circuits. The final two chapters present a unified coverage of sample-data and continuous-time signal processing systems.

  20. Analogy Mapping Development for Learning Programming

    Science.gov (United States)

    Sukamto, R. A.; Prabawa, H. W.; Kurniawati, S.

    2017-02-01

    Programming skill is an important skill for computer science students, whereas nowadays, there many computer science students are lack of skills and information technology knowledges in Indonesia. This is contrary with the implementation of the ASEAN Economic Community (AEC) since the end of 2015 which is the qualified worker needed. This study provided an effort for nailing programming skills by mapping program code to visual analogies as learning media. The developed media was based on state machine and compiler principle and was implemented in C programming language. The state of every basic condition in programming were successful determined as analogy visualization.

  1. ANALOG SIMULATION PROBLEMS NONSTATIONARY GAS DYNAMICS

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available In this paper the possibility of using hydraulic analog simulation in the study of problems of unsteady gas dynamics is considered. The analysis of differential equations of unsteady motion of bodies in supersonic flow using the theory of similarity and dimensional analysis. Obtained similarity criteria that must be identical for both the real gas flow and the modeling of fluid flow. Using a hydraulic analog modeling for research in non-stationary gas dynamics provides valuable information necessary for understanding the physics of the processes and the construction of more sophisticated mathematical models.

  2. Associative Pattern Recognition In Analog VLSI Circuits

    Science.gov (United States)

    Tawel, Raoul

    1995-01-01

    Winner-take-all circuit selects best-match stored pattern. Prototype cascadable very-large-scale integrated (VLSI) circuit chips built and tested to demonstrate concept of electronic associative pattern recognition. Based on low-power, sub-threshold analog complementary oxide/semiconductor (CMOS) VLSI circuitry, each chip can store 128 sets (vectors) of 16 analog values (vector components), vectors representing known patterns as diverse as spectra, histograms, graphs, or brightnesses of pixels in images. Chips exploit parallel nature of vector quantization architecture to implement highly parallel processing in relatively simple computational cells. Through collective action, cells classify input pattern in fraction of microsecond while consuming power of few microwatts.

  3. Space flight nutrition research: platforms and analogs

    Science.gov (United States)

    Smith, Scott M.; Uchakin, Peter N.; Tobin, Brian W.

    2002-01-01

    Conducting research during actual or simulated weightlessness is a challenging endeavor, where even the simplest activities may present significant challenges. This article reviews some of the potential obstacles associated with performing research during space flight and offers brief descriptions of current and previous space research platforms and ground-based analogs, including those for human, animal, and cell-based research. This review is intended to highlight the main issues of space flight research analogs and leave the specifics for each physiologic system for the other papers in this section.

  4. Pseudolog Digital-to-Analog Converter

    Science.gov (United States)

    Gooder, S. T.

    1986-01-01

    Sensitivity decreases by 10 at beginning of each input decade. Method conceived to convert binary-coded data to suitable linear form for stripchart recording. Strip-chart recordings obtained from typical pressure readings in a vacuum system during pumpdown. In reading curve, BCD digital vacuum-gage output processed by analog-to-digital converter in such way that only reading digits (but not range) appear in output. In range and reading, range also converted to analog and placed as most significant digit.

  5. A quadratic analog-to-digital converter

    Science.gov (United States)

    Harrison, D. C.; Staples, M. H.

    1980-01-01

    An analog-to-digital converter with a square root transfer function has been developed for use with a pair of CCD imaging detectors in the White Light Coronagraph/X-ray XUV Telescope experiment to be flown as part of the Internal Solar Polar Mission. It is shown that in background-noise-limited instrumentation systems a quadratic analog-to-digital converter will allow a maximum dynamic range with a fixed number of data bits. Low power dissipation, moderately fast conversion time, and reliability are achieved in the proposed design using standard components and avoiding nonlinear elements.

  6. Transparent Analogs for Alloy Phase Studies

    Science.gov (United States)

    Frazier, D. O.; Smith, James E., Jr.

    1987-01-01

    Report describes experiments to add information to data base supporting use of transparent, partially miscible liquids and solids as analogs in studies of alloy solidification. Behavior of these materials observed directly while they undergo liquid/liquid and liquid/solid phase transformations. Light-scattering techniques used to determine phase boundaries. Transparent analogs allow observation of both solidification patterns and processes leading to those patterns, whereas metal alloys require tedious post-solidification metallographic analyses because processes not generally observed. Experiments with transparent substances safer and cheaper since conducted at much lower temperatures.

  7. Analog graphic display method and apparatus

    Science.gov (United States)

    Kronberg, J.W.

    1991-08-13

    Disclosed are an apparatus and method for using an output device such as an LED to show the approximate analog level of a variable electrical signal wherein a modulating AC waveform is superimposed either on the signal or a reference voltage, both of which are then fed to a comparator which drives the output device. Said device flashes at a constant perceptible rate with a duty cycle which varies in response to variations in the level of the input signal. The human eye perceives these variations in duty cycle as analogous to variations in the level of the input signal. 21 figures.

  8. High-speed and high-resolution analog-to-digital and digital-to-analog converters

    NARCIS (Netherlands)

    van de Plassche, R.J.

    1989-01-01

    Analog-to-digital and digital-to-analog converters are important building blocks connecting the analog world of transducers with the digital world of computing, signal processing and data acquisition systems. In chapter two the converter as part of a system is described. Requirements of analog

  9. Compact Structural Test Generation for Analog Macros

    NARCIS (Netherlands)

    Kaal, V.; Kerkhoff, Hans G.

    1997-01-01

    A structural, fault-model based methodology for the generation of compact high-quality test sets for analog macros is presented. Results are shown for an IV-converter macro design. Parameters of so-called test configurations are optimized for detection of faults in a fault-list and an optimal

  10. Radiation Behavior of Analog Neural Network Chip

    Science.gov (United States)

    Langenbacher, H.; Zee, F.; Daud, T.; Thakoor, A.

    1996-01-01

    A neural network experiment conducted for the Space Technology Research Vehicle (STRV-1) 1-b launched in June 1994. Identical sets of analog feed-forward neural network chips was used to study and compare the effects of space and ground radiation on the chips. Three failure mechanisms are noted.

  11. Atwood and Poggendorff: an insightful analogy

    DEFF Research Database (Denmark)

    Coelho, Ricardo; Borges, Paulo; Avelar Sotomaior Karam, Ricardo

    2016-01-01

    - librium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving stu- dents’ comprehension of Newton’s laws and equilibrium....

  12. An iconic, analogical approach to grammaticalization

    NARCIS (Netherlands)

    Fischer, O.; Conradie, C.J.; Johl, R.; Beukes, M.; Fischer, O.; Ljungberg, C.

    2010-01-01

    This paper addresses a number of problems connected with the ‘apparatus’ used in grammaticalization theory. It will be argued that we get a better grip on what happens in processes of grammaticalization (and its ‘opposite’, lexicalization) if the process is viewed in terms of analogical processes,

  13. Analog voicing detector responds to pitch

    Science.gov (United States)

    Abel, R. S.; Watkins, H. E.

    1967-01-01

    Modified electronic voice encoder /Vocoder/ includes an independent analog mode of operation in addition to the conventional digital mode. The Vocoder is a bandwidth compression equipment that permits voice transmission over channels, having only a fraction of the bandwidth required for conventional telephone-quality speech transmission.

  14. Analog circuit design designing waveform processing circuits

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    The fourth volume in the set Designing Waveform-Processing Circuits builds on the previous 3 volumes and presents a variety of analog non-amplifier circuits, including voltage references, current sources, filters, hysteresis switches and oscilloscope trigger and sweep circuitry, function generation, absolute-value circuits, and peak detectors.

  15. A physical analogy to fuzzy clustering

    DEFF Research Database (Denmark)

    Jantzen, Jan

    2004-01-01

    This tutorial paper provides an interpretation of the membership assignment in the fuzzy clustering algorithm fuzzy c-means. The membership of a data point to several clusters is shown to be analogous to the gravitational forces between bodies of mass. This provides an alternative way to explain...

  16. Metaphor, Simile, Analogy and the Brain

    Science.gov (United States)

    Riddell, Patricia

    2016-01-01

    Fox argues that the poetic function of language fulfils the human need to symbolise. Metaphor, simile and analogy provide examples of the ways in which symbolic language can be used creatively. The neural representations of these processes therefore provide a means to determine the neurological basis of creative language. Neuro-imaging has…

  17. Invention through Form and Function Analogy

    Science.gov (United States)

    Rule, Audrey C.

    2015-01-01

    "Invention through Form and Function Analogy" is an invention book for teachers and other leaders working with youth who are involving students in the invention process. The book consists of an introduction and set of nine learning cycle formatted lessons for teaching the principles of invention through the science and engineering design…

  18. SSERVI Analog Regolith Simulant Testbed Facility

    Science.gov (United States)

    Minafra, J.; Schmidt, G. K.

    2016-12-01

    SSERVI's goals include supporting planetary researchers within NASA, other government agencies; private sector and hardware developers; competitors in focused prize design competitions; and academic sector researchers. The SSERVI Analog Regolith Simulant Testbed provides opportunities for research scientists and engineers to study the effects of regolith analog testbed research in the planetary exploration field. This capability is essential to help to understand the basic effects of continued long-term exposure to a simulated analog test environment. The current facility houses approximately eight tons of JSC-1A lunar regolith simulant in a test bin consisting of a 4 meter by 4 meter area. SSERVI provides a bridge between several groups, joining together researchers from: 1) scientific and exploration communities, 2) multiple disciplines across a wide range of planetary sciences, and 3) domestic and international communities and partnerships. This testbed provides a means of consolidating the tasks of acquisition, storage and safety mitigation in handling large quantities of regolith simulant Facility hardware and environment testing scenarios include, but are not limited to the following; Lunar surface mobility, Dust exposure and mitigation, Regolith handling and excavation, Solar-like illumination, Lunar surface compaction profile, Lofted dust, Mechanical properties of lunar regolith, and Surface features (i.e. grades and rocks) Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and planetary exploration activities at NASA Research Park, to academia and expanded commercial opportunities in California's Silicon Valley, as well as public outreach and education opportunities.

  19. RF digital-to-analog converter

    Science.gov (United States)

    Conway, P.H.; Yu, D.U.L.

    1995-02-28

    A digital-to-analog converter is disclosed for producing an RF output signal proportional to a digital input word of N bits from an RF reference input, N being an integer greater or equal to 2. The converter comprises a plurality of power splitters, power combiners and a plurality of mixers or RF switches connected in a predetermined configuration. 18 figs.

  20. The GMO-Nanotech (Dis)Analogy?

    Science.gov (United States)

    Sandler, Ronald; Kay, W. D.

    2006-01-01

    The genetically-modified-organism (GMO) experience has been prominent in motivating science, industry, and regulatory communities to address the social and ethical dimensions of nanotechnology. However, there are some significant problems with the GMO-nanotech analogy. First, it overstates the likelihood of a GMO-like backlash against…

  1. Analog Experiment for rootless cone eruption

    Science.gov (United States)

    Noguchi, R.; Hamada, A.; Suzuki, A.; Kurita, K.

    2017-09-01

    Rootless cone is a unique geomorphological landmark to specify igneous origin of investigated terrane, which is formed by magma-water interaction. To understand its formation mechanism we conducted analog experiment for heat-induced vesiculation by using hot syrup and sodium bicarbonate solution.

  2. The Altiplano-Puna Plateau as an Analog for Mars

    Science.gov (United States)

    de Silva, S. L.; Byrnes, J. M.; Crown, D. A.; Zimbelman, J. R.; Jimenez, N.; Bills, B. G.

    2002-12-01

    The Altiplano-Puna Plateau of the Central Andes of Bolivia has experienced a climatic and geologic evolution that has resulted in an enticing array of potential Martian analog geologic environments and features. Elevated ~3 ? 4km above the adjacent Atacama desert, the Altiplano-Puna is the highest plateau in the world associated with extensive volcanism; it is second only to Tibet in height and extent. The high elevation adds extreme cold, wind, and lower atmospheric pressure to a hyper-arid climate making this region a compelling analog environment for Mars. The plateau is dominated by the Altiplano basin, which developed as a major intermontane basin since at least 25Ma. This is flanked by major volcanic provinces to the east and south. To the south is the Altiplano-Puna Volcanic Complex (APVC) where regionally extensive ignimbrite sheets and associated eruptive centers are amongst the largest known volcanic features in the world. The region has proven to be an excellent natural laboratory for remote sensing and field-based studies of volcanism. The extreme cold, wind, and the wide diurnal temperature range, results in geomorphic expressions dominated by physical weathering and aeolian erosion. These factors make this region one of the premier analog environments for Martian features like Amazonis Planitia, and Hadriaca, Alba, and Tyrrhena paterae, as well as the enigmatic Medusa Fossae Formation (MFF) materials. Large ignimbrite shields, are prominent features of volcanic geology of the plateau and are the subject of an ongoing terrestrial analog study for the MFF. The Altiplano basin preserves a long Pleistocene lake history recorded in a well-preserved lake shore geomorphology consisting of both erosional and depositional features. These features are easily identified and studied in the field and on remotely sensed images and may lend valuable insight into the debate over putative paleoshorelines in the northern plains of Mars. Throughout the basin are several

  3. Optical folding-flash analog-to-digital converter with analog encoding.

    Science.gov (United States)

    Jalali, B; Xie, Y M

    1995-09-15

    We describe an optically assisted folding-flash analog-to-digital converter. The periodic transfer function of the Mach-Zehnder interferometer is used to perform analog folding on the electronic signal to be quantized. A novel analog encoding scheme for efficient generation of gray code digital data is proposed. The new encoding scheme eliminates the requirement for interferometers with ultralow V(pi), which, so far, has hindered the development of such systems. The encoding concept is experimentally demonstrated through the use of LiNbO(3) modulators.

  4. Quantifying Uncertainty of Wind Power Production Through an Analog Ensemble

    Science.gov (United States)

    Shahriari, M.; Cervone, G.

    2016-12-01

    The Analog Ensemble (AnEn) method is used to generate probabilistic weather forecasts that quantify the uncertainty in power estimates at hypothetical wind farm locations. The data are from the NREL Eastern Wind Dataset that includes more than 1,300 modeled wind farms. The AnEn model uses a two-dimensional grid to estimate the probability distribution of wind speed (the predictand) given the values of predictor variables such as temperature, pressure, geopotential height, U-component and V-component of wind. The meteorological data is taken from the NCEP GFS which is available on a 0.25 degree grid resolution. The methodology first divides the data into two classes: training period and verification period. The AnEn selects a point in the verification period and searches for the best matching estimates (analogs) in the training period. The predictand value at those analogs are the ensemble prediction for the point in the verification period. The model provides a grid of wind speed values and the uncertainty (probability index) associated with each estimate. Each wind farm is associated with a probability index which quantifies the degree of difficulty to estimate wind power. Further, the uncertainty in estimation is related to other factors such as topography, land cover and wind resources. This is achieved by using a GIS system to compute the correlation between the probability index and geographical characteristics. This study has significant applications for investors in renewable energy sector especially wind farm developers. Lower level of uncertainty facilitates the process of submitting bids into day ahead and real time electricity markets. Thus, building wind farms in regions with lower levels of uncertainty will reduce the real-time operational risks and create a hedge against volatile real-time prices. Further, the links between wind estimate uncertainty and factors such as topography and wind resources, provide wind farm developers with valuable

  5. Radioiodinated fatty acid analogs for myocardial imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ruyan, M.K.

    1993-01-01

    Fatty acids are the preferred substrate for the normoxic heart. About sixty percent of the energy required by the myocardium is provided by fatty acid [beta]-oxidation. Many scientists have focused on the alterations in fatty acid metabolism in the ischemic heart for the development of radiolabelled fatty acids for functional imaging of the heart. Three main categories of compounds were synthesized: tetrazoles (1 and 2), glycidic and [alpha]-methylene acids (3-5), and analogs of oleic acid (6,7 and 7A). The tetrazole group has a similar pKa and size to that of a carboxyl group; however, such fatty acid analogs cannot undergo normal fatty acid metabolism. Glycidic and [alpha]-methylene analogs are potential irreversible inhibitors of fatty acid metabolism. Oleic acid analogs were investigated to assess the affect of stereochemical consequences on biodistribution. The key intermediates in the synthesis of the target compounds were [omega]-nitrophenyl alkylcarboxylic acids and alcohols, which were made using a variety of cross-coupling reactions. The Wittig reaction, which was used in the synthesis of tetrazole 1 and glycidic acid 3, gave low yields of the cross-coupled products. The remaining target compounds were synthesized by condensation of appropriate RCu (CN) ZnI and substituted benzyl bromides or by Pd[sup II] catalyzed cross-coupling of substituted arylhalides with suitable alkynes. The latter two reactions produced much higher yields of the desired products. All of the target compounds were radiolabeled with [sup 125]I by various Cu(I) catalyzed radioiodine exchange procedures and were then subjected to tissue biodistribution (TD) studies in rats. Except for the 15-(4-iodophenyl)-2-methylene-pentadecanoic acid (5), all of the fatty acid analogs failed to surpass clinically-used 15-(4-iodophenyl)pentadecanoic acid (IPPA) in their ability to be taken up and retained by the rat myocardium.

  6. In vitro evaluation of nicotinamide riboside analogs against Haemophilus influenzae.

    Science.gov (United States)

    Godek, C P; Cynamon, M H

    1990-08-01

    Exogenous NAD, nicotinamide mononucleotide, or nicotinamide riboside is required for the growth of Haemophilus influenzae. These compounds have been defined as the V-factor growth requirement. We have previously shown that the internalization of nicotinamide riboside is energy dependent and carrier mediated with saturation kinetics. Thionicotinamide riboside, 3-pyridinealdehyde riboside, 3-acetylpyridine riboside, and 3-aminopyridine riboside were prepared from their corresponding NAD analogs. These compounds and several other nicotinamide riboside analogs were evaluated for their ability to support the growth of H. influenzae and for their ability to block the uptake of [carbonyl-14C]nicotinamide riboside by H. influenzae. 3-Aminopyridine riboside blocked the uptake of [carbonyl-14C]nicotinamide riboside and inhibited the growth of H. influenzae when NAD, nicotinamide mononucleotide, or nicotinamide riboside served as the V factor. The antibacterial activity of 3-aminopyridine riboside was found to be specific for H. influenzae but had no effect on the growth of Staphylococcus aureus or Escherichia coli. In additional experiments by reversed-phase high-performance liquid chromatography, it was determined that whole cells of H. influenzae degrade 3-aminopyridine adenine dinucleotide to 3-aminopyridine riboside, which is then internalized. Inside the cell, 3-aminopyridine riboside has the ability to interfere with the growth of H. influenzae by an undetermined mechanism.

  7. A potential inhibitory role for the new truncated variant of somatostatin receptor 5, sst5TMD4, in pituitary adenomas poorly responsive to somatostatin analogs.

    Science.gov (United States)

    Durán-Prado, Mario; Saveanu, Alexandru; Luque, Raul M; Gahete, Manuel D; Gracia-Navarro, Francisco; Jaquet, Philippe; Dufour, Henry; Malagón, María M; Culler, Michael D; Barlier, Anne; Castaño, Justo P

    2010-05-01

    Somatostatin (SST) receptors, specially sst2 and sst5, provide a valuable target to inhibit excessive hormone release and cell growth in pituitary tumors by using SST analogs (SSAs). Unfortunately, an appreciable proportion of tumors fail to respond to SSA despite expressing high levels of one or more ssts. Recently we identified two novel truncated sst5 variants, sst5TMD5, and sst5TMD4, absent in normal pituitary but expressed in pituitary tumors. We aimed at exploring the potential role of sst5TMD5 and sst5TMD4 in the poor response of some tumors to SSA in vivo and in vitro. Specifically, 25 somatotropinomas showing different responses to octreotide in vivo and sst2 (BIM-23197)- and sst5(BIM-23268)-selective compounds in vitro were screened for sst5TMD5/sst5TMD4 expression by real-time PCR. Relationships between ssts expression and in vivo and in vitro secretory response of the corresponding pituitary samples were assessed. sst5TMD5 was absent in all samples analyzed. sst5TMD4 was found in 85% of tumors, and its expression was positively correlated to that of sst5 (R(2) = 0.79, P < 0.001). Expression of sst5TMD4 was negatively correlated with the ability of octreotide to reduce GH levels in vivo and partially negatively correlated with inhibition of GH secretion by an sst5 selective agonist (BIM-23268) in vitro. These results indicate that sst5TMD4 is related to the reduced ability of octreotide at normalizing hormone secretion in poorly responsive tumors in vivo. Further studies will help to evaluate the potential use of sst5TMD4 expression in surgically removed pituitary adenomas as a predictor of the subsequent response of different pituitary tumors to SSA therapy.

  8. Analogical reasoning in children with specific language impairment: Evidence from a scene analogy task.

    Science.gov (United States)

    Krzemien, Magali; Jemel, Boutheina; Maillart, Christelle

    2017-01-01

    Analogical reasoning is a human ability that maps systems of relations. It develops along with relational knowledge, working memory and executive functions such as inhibition. It also maintains a mutual influence on language development. Some authors have taken a greater interest in the analogical reasoning ability of children with language disorders, specifically those with specific language impairment (SLI). These children apparently have weaker analogical reasoning abilities than their aged-matched peers without language disorders. Following cognitive theories of language acquisition, this deficit could be one of the causes of language disorders in SLI, especially those concerning productivity. To confirm this deficit and its link to language disorders, we use a scene analogy task to evaluate the analogical performance of SLI children and compare them to controls of the same age and linguistic abilities. Results show that children with SLI perform worse than age-matched peers, but similar to language-matched peers. They are more influenced by increased task difficulty. The association between language disorders and analogical reasoning in SLI can be confirmed. The hypothesis of limited processing capacity in SLI is also being considered.

  9. Human performance profiles for planetary analog extra-vehicular activities: 120 day and 30 day analog missions

    Science.gov (United States)

    Swarmer, Tiffany M.

    Understanding performance factors for future planetary missions is critical for ensuring safe and successful planetary extra-vehicular activities (EVAs). The goal of this study was to gain operational knowledge of analog EVAs and develop biometric profiles for specific EVA types. Data was collected for a 120 and 30 day analog planetary exploration simulation focusing on EVA type, pre and post EVA conditions, and performance ratings. From this five main types of EVAs were performed: maintenance, science, survey/exploratory, public relations, and emergency. Each EVA type has unique characteristics and performance ratings showing specific factors in chronological components, environmental conditions, and EVA systems that have an impact on performance. Pre and post biometrics were collected to heart rate, blood pressure, and SpO2. Additional data about issues and specific EVA difficulties provide some EVA trends illustrating how tasks and suit comfort can negatively affect performance ratings. Performance decreases were noted for 1st quarter and 3rd quarter EVAs, survey/exploratory type EVAs, and EVAs requiring increased fine and gross motor function. Stress during the simulation is typically higher before the EVA and decreases once the crew has returned to the habitat. Stress also decreases as the simulation nears the end with the 3rd and 4th quarters showing a decrease in stress levels. Operational components and studies have numerous variable and components that effect overall performance, by increasing the knowledge available we may be able to better prepare future crews for the extreme environments and exploration of another planet.

  10. Optimal neural computations require analog processors

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.

    1998-12-31

    This paper discusses some of the limitations of hardware implementations of neural networks. The authors start by presenting neural structures and their biological inspirations, while mentioning the simplifications leading to artificial neural networks. Further, the focus will be on hardware imposed constraints. They will present recent results for three different alternatives of parallel implementations of neural networks: digital circuits, threshold gate circuits, and analog circuits. The area and the delay will be related to the neurons` fan-in and to the precision of their synaptic weights. The main conclusion is that hardware-efficient solutions require analog computations, and suggests the following two alternatives: (i) cope with the limitations imposed by silicon, by speeding up the computation of the elementary silicon neurons; (2) investigate solutions which would allow the use of the third dimension (e.g. using optical interconnections).

  11. Analog fault diagnosis by inverse problem technique

    KAUST Repository

    Ahmed, Rania F.

    2011-12-01

    A novel algorithm for detecting soft faults in linear analog circuits based on the inverse problem concept is proposed. The proposed approach utilizes optimization techniques with the aid of sensitivity analysis. The main contribution of this work is to apply the inverse problem technique to estimate the actual parameter values of the tested circuit and so, to detect and diagnose single fault in analog circuits. The validation of the algorithm is illustrated through applying it to Sallen-Key second order band pass filter and the results show that the detecting percentage efficiency was 100% and also, the maximum error percentage of estimating the parameter values is 0.7%. This technique can be applied to any other linear circuit and it also can be extended to be applied to non-linear circuits. © 2011 IEEE.

  12. High-speed analog CMOS pipeline system

    Science.gov (United States)

    Möschen, J.; Caldwell, A.; Hervas, L.; Hosticka, B.; Kötz, U.; Sippach, B.

    1990-03-01

    We present a switched-capacitor readout system for high speed analog signals. It consists of a 10 MHz four-channel delay-line chip with 58 samples per channel and a 12 channel buffer chip with a sampling rate of 1 MHz and a depth of nine samples. In addition the buffer chip includes an analog multiplexer with 25 inputs for the buffer channels and for 13 additional unbuffered signals. Both chips have been fabricated in CMOS-technology and will be used for the readout of the ZEUS high resolution calorimeter. The circuit and chip concept will be presented and some design optimizations will be discussed. Measurements from integrated prototypes will be given including some experimental data from irradiated chips.

  13. Playing with a double-edged sword: Analogies in biochemistry

    Science.gov (United States)

    Orgill, Marykay

    Analogy pervades our everyday reasoning. No situation we encounter is exactly like a situation we have encountered previously, and our ability to learn and survive in the world is based on our ability to find similarities between past and present situations and use the knowledge we have gained from past situations to manage current situations. Analogies can be powerful teaching tools because they can make new material intelligible to students by comparing it to material that is already familiar. It is clear, though, that not all analogies are good and that not all good analogies are useful to all students. In this study, I have used textbook analysis, classroom observations, student interviews and instructor interviews to determine the role that analogies play in biochemistry learning. Analogies are an important teaching technique in biochemistry classes, being used more often in both biochemistry classes and textbooks than they are in high school chemistry classes and textbooks. Most biochemistry students like, pay particular attention to, and remember the analogies their instructors provide; and they use these analogies to understand, visualize, and recall information from class. Even though students like and use analogies, they do not understand what analogies are or the mechanism by which they improve learning. For the students, analogies are simply any teaching technique that eases understanding, visualization, or recall. Instructors, on the other hand, have a good understanding of what analogies are and of how they should be presented in class; but they do not use analogies as effectively as they should. They do not plan, explain or identify the limitations of the analogies they use in class. However, regardless of how effectively instructors present analogies in class, this study indicates that, in general, analogies are useful in promoting understanding, visualization, recall, and motivation in biochemistry students at all levels. They would be even more

  14. Medical treatment of acromegaly: comorbidities and their reversibility by somatostatin analogs.

    Science.gov (United States)

    Tolis, George; Angelopoulos, Nicholas G; Katounda, Eugenia; Rombopoulos, Grigorios; Kaltzidou, Victoria; Kaltsas, Dimitrios; Protonotariou, Anthi; Lytras, Aristides

    2006-01-01

    Relief of symptoms can be achieved following surgery for growth hormone (GH)-secreting adenomas, as well as after pharmacological therapy with somatostatin analogs. Recently, long-acting somatostatin analog depot formulations, octreotide LAR and lanreotide SR have become available. Somatostatin analogs control GH/insulin-like growth factor (IGF)-1 excess, induce tumor shrinkage in a high proportion of patients, improve symptoms of acromegaly with relatively limited side effects and are successfully administered in patients not suitable for surgery. Furthermore, preoperative somatostatin analogs have been suggested to improve outcome for tumors with limited invasiveness, while surgical tumor debulking in cases that are, at least partially, somatostatin resistant, increases the achievement of normal IGF-1 levels by postoperative somatostatin analog treatment. Effective control of hypertension, as well as diabetes, is mandatory in order to reduce the increased vascular morbidity/mortality. Control of GH/IGF-1 excess generally improves glucose metabolism. Somatostatin analogs improve insulin sensitivity, exerting, however, a concomitant direct inhibitory effect on insulin secretion, with a net balance leaning towards a deterioration in glucose homeostasis. As a result, oral insulin secretagogues (and/or insulin) should probably be preferred to insulin sensitizers in acromegalic patients developing diabetes while on somatostatin analogs. Nevertheless, glucose tolerance remains normal in most of the nondiabetic acromegalic patients, while diabetic acromegalic patients on insulin are at risk for hypoglycemia during initiation of somatostatin analog therapy. Although successful management of acromegaly has been associated with improvement in morphological and functional parameters of cardiomyopathy, limited and conflicting information is available regarding the effect on blood pressure control. Contradictory results have also been reported regarding sleep hypopnea or apnea

  15. N-Zero Integrated Analog Classifier (NINA)

    Science.gov (United States)

    2017-03-01

    detected signals. For physical- asset detection and classification, passive piezoelectric MEMS resonant seismic sensors will be utilized to produce...computational circuits operating deep in the weak inversion regime and non-volatile analog memories to classify seismic signals at extremely low...frequencies to maximize the sensor output voltage with generator signal. Figure 3. Vibration signal spectrum measured from by a sensor located atop the

  16. Atomtronics: Ultracold Atom Analogs of Electronic Devices

    Science.gov (United States)

    2006-06-23

    to leave the base compared to entering the col- build a transistor . Bipolar junction transistors ( BJT ) lector. Because of this, most of the current...voltage curve exploits the existence of superfluid and insulating regimes in the phase diagram. "lie atomt.roinc analog of a bipolar junction transistor ...of a bipolar junction transistor exhibits large negative gain. Our results provide the building blocks for more advanced atomtronic devices and

  17. Analog Processor To Solve Optimization Problems

    Science.gov (United States)

    Duong, Tuan A.; Eberhardt, Silvio P.; Thakoor, Anil P.

    1993-01-01

    Proposed analog processor solves "traveling-salesman" problem, considered paradigm of global-optimization problems involving routing or allocation of resources. Includes electronic neural network and auxiliary circuitry based partly on concepts described in "Neural-Network Processor Would Allocate Resources" (NPO-17781) and "Neural Network Solves 'Traveling-Salesman' Problem" (NPO-17807). Processor based on highly parallel computing solves problem in significantly less time.

  18. An introduction to analog and digital communications

    CERN Document Server

    Haykin, Simon

    2012-01-01

    The second edition of this accessible book provides readers with an introductory treatment of communication theory as applied to the transmission of information-bearing signals. While it covers analog communications, the emphasis is placed on digital technology. It begins by presenting the functional blocks that constitute the transmitter and receiver of a communication system. Readers will next learn about electrical noise and then progress to multiplexing and multiple access techniques.

  19. Targeting thyroid diseases with TSH receptor analogs.

    Science.gov (United States)

    Galofré, Juan C; Chacón, Ana M; Latif, Rauf

    2013-12-01

    The thyroid-stimulating hormone (TSH) receptor (TSHR) is a major regulator of thyroid function and growth, and is the key antigen in several pathological conditions including hyperthyroidism, hypothyroidism, and thyroid tumors. Various effective treatment strategies are currently available for many of these clinical conditions such as antithyroid drugs or radioiodine therapy, but they are not devoid of side effects. In addition, treatment of complications of Graves' disease such as Graves' ophthalmopathy is often difficult and unsatisfactory using current methods. Recent advances in basic research on both in vitro and in vivo models have suggested that TSH analogs could be used for diagnosis and treatment of some of the thyroid diseases. The advent of high-throughput screening methods has resulted in a group of TSH analogs called small molecules, which have the potential to be developed as promising drugs. Small molecules are low molecular weight compounds with agonist, antagonist and, in some cases, inverse agonist activity on TSHR. This short review will focus on current advances in development of TSH analogs and their potential clinical applications. Rapid advances in this field may lead to the conduct of clinical trials of small molecules related to TSHR for the management of Graves' disease, thyroid cancer, and thyroid-related osteoporosis in the coming years. Copyright © 2012 SEEN. Published by Elsevier Espana. All rights reserved.

  20. Novel Gemini vitamin D3 analogs

    DEFF Research Database (Denmark)

    Okamoto, Ryoko; Gery, Sigal; Kuwayama, Yoshio

    2014-01-01

    We have synthesized 39 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] analogs having two side chains attached to carbon-20 (Gemini) with various modifications and compared their anticancer activities. Five structure-function rules emerged to identify analogs with enhanced anticancer activity. One...... of these active analogs, BXL-01-0126, was more potent than 1,25(OH)2D3 in mediating 50% clonal inhibition of cancer cell growth. Murine studies found that BXL-01-0126 and 1,25(OH)2D3 had nearly the same potency to raise serum calcium levels. Taken together, BXL-01-0126 when compared to 1,25(OH)2D3 has greater...... anticancer potency, but similar toxicity causing hypercalcemia. We focused on the effect of these compounds on the stimulation of expression of human cathelicidin antimicrobial peptide (CAMP) whose gene has a vitamin D response element in its promoter. Expression of CAMP mRNA and protein increased in a dose...

  1. Sensing Methods for Detecting Analog Television Signals

    Science.gov (United States)

    Rahman, Mohammad Azizur; Song, Chunyi; Harada, Hiroshi

    This paper introduces a unified method of spectrum sensing for all existing analog television (TV) signals including NTSC, PAL and SECAM. We propose a correlation based method (CBM) with a single reference signal for sensing any analog TV signals. In addition we also propose an improved energy detection method. The CBM approach has been implemented in a hardware prototype specially designed for participating in Singapore TV white space (WS) test trial conducted by Infocomm Development Authority (IDA) of the Singapore government. Analytical and simulation results of the CBM method will be presented in the paper, as well as hardware testing results for sensing various analog TV signals. Both AWGN and fading channels will be considered. It is shown that the theoretical results closely match with those from simulations. Sensing performance of the hardware prototype will also be presented in fading environment by using a fading simulator. We present performance of the proposed techniques in terms of probability of false alarm, probability of detection, sensing time etc. We also present a comparative study of the various techniques.

  2. Clinical utility of insulin and insulin analogs

    Science.gov (United States)

    Sanlioglu, Ahter D.; Altunbas, Hasan Ali; Balci, Mustafa Kemal; Griffith, Thomas S.; Sanlioglu, Salih

    2013-01-01

    Diabetes is a pandemic disease characterized by autoimmune, genetic and metabolic abnormalities. While insulin deficiency manifested as hyperglycemia is a common sequel of both Type-1 and Type-2 diabetes (T1DM and T2DM), it does not result from a single genetic defect—rather insulin deficiency results from the functional loss of pancreatic β cells due to multifactorial mechanisms. Since pancreatic β cells of patients with T1DM are destroyed by autoimmune reaction, these patients require daily insulin injections. Insulin resistance followed by β cell dysfunction and β cell loss is the characteristics of T2DM. Therefore, most patients with T2DM will require insulin treatment due to eventual loss of insulin secretion. Despite the evidence of early insulin treatment lowering macrovascular (coronary artery disease, peripheral arterial disease and stroke) and microvascular (diabetic nephropathy, neuropathy and retinopathy) complications of T2DM, controversy exists among physicians on how to initiate and intensify insulin therapy. The slow acting nature of regular human insulin makes its use ineffective in counteracting postprandial hyperglycemia. Instead, recombinant insulin analogs have been generated with a variable degree of specificity and action. Due to the metabolic variability among individuals, optimum blood glucose management is a formidable task to accomplish despite the presence of novel insulin analogs. In this article, we present a recent update on insulin analog structure and function with an overview of the evidence on the various insulin regimens clinically used to treat diabetes. PMID:23584214

  3. Kukoamine A analogs with lipoxygenase inhibitory activity.

    Science.gov (United States)

    Hadjipavlou-Litina, Dimitra; Garnelis, Thomas; Athanassopoulos, Constantinos M; Papaioannou, Dionissios

    2009-10-01

    Kukoamine A (KukA) is a spermine (SPM) conjugate with dihydrocaffeic acid (DHCA), with interesting biological activities. The four possible regioisomers of KukA, as well as a series of KukA analogs incorporating changes in either the SPM or the DHCA structural units, were evaluated for their antioxidant activity and their inhibitory activity on soybean lipoxygenase (LOX) and lipid peroxidation. The reducing properties of the compounds were evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay and found to be in the range 5-97.5%. KukA significantly inhibits LOX with IC(50) 9.5 microM. All tested analogs inhibited lipid peroxidation in the range of 11-100%. The most potent compounds KukA and its analog 3, in which the DHCA units had been replaced by O,O9-dimethylcaffeic acid units, were studied for their anti-inflammatory activity in vivo on rat paw edema induced by carrageenan and found to be of comparable activity to indomethacin. The results of the biological tests are discussed in terms of structural characteristics.

  4. Principles for Integrating Mars Analog Science, Operations, and Technology Research

    Science.gov (United States)

    Clancey, William J.

    2003-01-01

    During the Apollo program, the scientific community and NASA used terrestrial analog sites for understanding planetary features and for training astronauts to be scientists. Human factors studies (Harrison, Clearwater, & McKay 1991; Stuster 1996) have focused on the effects of isolation in extreme environments. More recently, with the advent of wireless computing, we have prototyped advanced EVA technologies for navigation, scheduling, and science data logging (Clancey 2002b; Clancey et al., in press). Combining these interests in a single expedition enables tremendous synergy and authenticity, as pioneered by Pascal Lee's Haughton-Mars Project (Lee 2001; Clancey 2000a) and the Mars Society s research stations on a crater rim on Devon Island in the High Canadian Arctic (Clancey 2000b; 2001b) and the Morrison Formation of southeast Utah (Clancey 2002a). Based on this experience, the following principles are proposed for conducting an integrated science, operations, and technology research program at analog sites: 1) Authentic work; 2) PI-based projects; 3) Unencumbered baseline studies; 4) Closed simulations; and 5) Observation and documentation. Following these principles, we have been integrating field science, operations research, and technology development at analog sites on Devon Island and in Utah over the past five years. Analytic methods include work practice simulation (Clancey 2002c; Sierhuis et a]., 2000a;b), by which the interaction of human behavior, facilities, geography, tools, and procedures are formalized in computer models. These models are then converted into the runtime EVA system we call mobile agents (Clancey 2002b; Clancey et al., in press). Furthermore, we have found that the Apollo Lunar Surface Journal (Jones, 1999) provides a vast repository or understanding astronaut and CapCom interactions, serving as a baseline for Mars operations and quickly highlighting opportunities for computer automation (Clancey, in press).

  5. Deficits in analogical reasoning in adolescents with traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Daniel C Krawczyk

    2010-08-01

    Full Text Available Individuals with traumatic brain injury (TBI exhibit deficits in executive control, which may impact their reasoning abilities. Analogical reasoning requires working memory and inhibitory abilities. In this study, we tested adolescents with moderate to severe TBI and typically-developing (TD controls on a set of picture analogy problems. Three factors were varied: complexity (number of relations in the problems, distraction (distractor item present or absent, and animacy (living or non-living items in the problems. We found that TD adolescents performed significantly better overall than TBI adolescents. There was also an age effect present in the TBI group where older participants performed better than younger ones. This age effect was not observed in the TD group. Performance was affected by complexity and distraction. Further, TBI participants exhibited lower performance with distractors present than TD participants. The reasoning deficits exhibited by the TBI participants were correlated with measures of executive function that required working memory updating, attention, and attentional screening. Using MRI-derived measures of cortical thickness, correlations were carried out between task accuracy and cortical thickness. The TD adolescents showed negative correlations between thickness and task accuracy in frontal and temporal regions consistent with cortical maturation in these regions. This study demonstrates that adolescent TBI results in impairments in analogical reasoning ability. Further, TBI youth have difficulty effectively screening out distraction, which may lead to failures in comprehension of the relations among items in visual scenes. Lastly, TBI youth fail to show robust cortical-behavior correlations as observed in TD individuals.

  6. Nonlinear feedback reduces analog-to-digital converter error

    Science.gov (United States)

    Munoz, R. M.

    1965-01-01

    Nonlinear analog-to-digital converter measures the analog input level and continuously adjusts the digital readout scale sensitivity to effectively increase the accuracy. It is able to acquire more accurate low-level data.

  7. Unconscious violinists and the use of analogies in moral argument

    OpenAIRE

    Wiland, E.

    2000-01-01

    Analogies are the stuff out of which normative moral philosophy is made. Certainly one of the most famous analogies constructed by a philosopher in order to argue for a specific controversial moral conclusion is the one involving Judith Thomson's unconscious violinist. Reflection upon this analogy is meant to show us that abortion is generally not immoral even if the prenatal have the same moral status as the postnatal. This was and still is a controversial conclusion, and yet the analogy doe...

  8. Using Analogies as an Experiential Learning Technique in Multicultural Education

    Science.gov (United States)

    Suthakaran, V.; Filsinger, Keri; White, Brittany

    2013-01-01

    In this article the authors specifically address the use of narratives in the form of analogies as an experiential learning activity. The use of analogies as an experiential learning tool in multicultural education can be helpful in a number of ways. Analogies provide an alternative tool for processing multicultural topics with students who have…

  9. Administration of Biosimilar Insulin Analogs: Role of Devices.

    Science.gov (United States)

    Heinemann, Lutz; Fritz, Ingo; Khatami, Hootan; Edelman, Steven V

    2017-02-01

    With the expiration of patent protection for several originator insulin analog molecules, the availability of insulin analog copies is set to increase. Many regulatory authorities have developed, and continue to refine, guidelines for the approval of biosimilar insulin analogs. Aspects such as the structure, pharmacokinetics and pharmacodynamics, efficacy, safety, and immunogenicity of biosimilar insulin analogs are extensively addressed in these guidelines, but how the biosimilar insulin analog is administered to people with diabetes is not usually a topic. The aim of this article is to highlight that the delivery device-drug combination is of particular importance. Regulatory, legal, and practical aspects of the delivery device, be it a syringe, pen, or pump, have to be considered in the context of biosimilar insulin analogs. Although the safety and efficacy of biosimilar insulin analogs per se are of primary importance for physicians and people with diabetes, functions and features of the devices used for administration also require attention from a practical point of view. Unfortunately, although there are several clinical studies investigating the technical aspects of and patient preference for the originator insulin analog pens, there are currently very little published data for nonoriginator or biosimilar insulin analog pens. In addition, it is not known if it is safe to assume that a biosimilar insulin analog cartridge is compatible with an existing originator insulin analog pen. We believe that there is a need for more discussion on the role of devices for administration of biosimilar insulin analogs.

  10. Circuit with a successive approximation analog to digital converter

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    During successive approximation analog to digital conversion a series of successive digital reference values is selected that converges towards a digital representation of an analog input signal. An analog reference signal is generated dependent on the successive digital reference values and

  11. Circuit with a successive approximation analog to digital converter

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    During successive approximation analog to digital conversion a series of successive digital reference values is selected that converges towards a digital representation of an analog input signal. An analog reference signal is generated dependent on the successive digital reference values and

  12. Functional DNA: Teaching Infinite Series through Genetic Analogy

    Science.gov (United States)

    Kowalski, R. Travis

    2011-01-01

    This article presents an extended analogy that connects infinite sequences and series to the science of genetics, by identifying power series as "DNA for a function." This analogy allows standard topics such as convergence tests or Taylor approximations to be recast in a "forensic" light as mathematical analogs of genetic concepts such as DNA…

  13. Natural Polyphenols and their Synthetic Analogs as Emerging Anticancer Agents.

    Science.gov (United States)

    Colomer, Ramon; Sarrats, Ariadna; Lupu, Ruth; Puig, Teresa

    2017-01-01

    Polyphenols are a structural class of natural and synthetic organic chemicals which contain phenol units. Numerous epidemiological, preclinical and clinical studies have strongly supported their benefical effects for human health. Polyphenols group include molecules of utterly different complexity grades, ranging from simple molecules to highly polymerized structures. They are classified into: Phenolic acids, Flavonoids, Lignans and the less common Stilbenes. This work first intends to review the current studies on classification, chemical composition and metabolism of polyphenols. Then, we have reported cancer preventive and treatment effects of polyphenols, especially focused in the green tea polyphenol (GTP) (-)-Epigallocatechin-3-gallate (EGCG). Polyphenols such as EGCG and their synthetic analogs interfere in carcinogenesis by modulating and regulating multiple signaling pathways and transcription factors, membrane-associated receptor tyrosine kinases (RTKs), fatty acid metabolism and lipid rafts or methylation together with other emerging targets such as proteasome, telomerase and cancer stem cells. Here, we have reviewed several potential molecular targets of polyphenols (mainly EGCG and EGCG analogs) and their anticancer effects in cellular and animal models of different human carcinomas and we have also listed Phases I and II clinical trials conducted to study the antitumor properties of GTPs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. An optimized analog to digital converter for WLAN analog front end

    Science.gov (United States)

    Mao, Ye; Yumei, Zhou; Bin, Wu; Jianhua, Jiang

    2012-04-01

    A 10 bit 80 MSPS analog to digital converter optimized for WLAN analog front end is presented. In contrast to conventional 1.5 bit pipeline architecture, four optimized multi-bit multiply digital to analog converter stages are implemented. An on-chip low-noise reference buffer is proposed for SoC integration purposes, and a wide-bandwidth wide swing sample and hold amplifier is also presented for achieving a good dynamic range. The converter was fabricated in 0.18 μm 1P6M CMOS technology, and the core area occupies approximately 0.85 mm2. Measured results show that with an 11 MHz input signal, it provides a 9.4 bit effective number of bits and a 72 dBc spurious frequency dynamic range when sampled at 80 MHz.

  15. SSERVI Analog Regolith Simulant Testbed Facility

    Science.gov (United States)

    Minafra, Joseph; Schmidt, Gregory; Bailey, Brad; Gibbs, Kristina

    2016-10-01

    The Solar System Exploration Research Virtual Institute (SSERVI) at NASA's Ames Research Center in California's Silicon Valley was founded in 2013 to act as a virtual institute that provides interdisciplinary research centered on the goals of its supporting directorates: NASA Science Mission Directorate (SMD) and the Human Exploration & Operations Mission Directorate (HEOMD).Primary research goals of the Institute revolve around the integration of science and exploration to gain knowledge required for the future of human space exploration beyond low Earth orbit. SSERVI intends to leverage existing JSC1A regolith simulant resources into the creation of a regolith simulant testbed facility. The purpose of this testbed concept is to provide the planetary exploration community with a readily available capability to test hardware and conduct research in a large simulant environment.SSERVI's goals include supporting planetary researchers within NASA, other government agencies; private sector and hardware developers; competitors in focused prize design competitions; and academic sector researchers.SSERVI provides opportunities for research scientists and engineers to study the effects of regolith analog testbed research in the planetary exploration field. This capability is essential to help to understand the basic effects of continued long-term exposure to a simulated analog test environment.The current facility houses approximately eight tons of JSC-1A lunar regolith simulant in a test bin consisting of a 4 meter by 4 meter area, including dust mitigation and safety oversight.Facility hardware and environment testing scenarios could include, Lunar surface mobility, Dust exposure and mitigation, Regolith handling and excavation, Solar-like illumination, Lunar surface compaction profile, Lofted dust, Mechanical properties of lunar regolith, Surface features (i.e. grades and rocks)Numerous benefits vary from easy access to a controlled analog regolith simulant testbed, and

  16. Digital to Analog Converter Dac 0800 with Pc-based

    OpenAIRE

    Dedy Erwan Kustianto; Ir. Irawan Nimara, MM

    2000-01-01

    Computer produces a digital signal output of logic "0" and "1". While electronicdevices typically use an analog signal as a voltage source that a certain amount.Electronic devices that require analog signals can be connected to a computer using adigital to analog converter circuit. Digital to analog converter is used to change thedigital signal into analogue signal.To be able to relate to the computer to analog converter circuit, an interface is needed.The interface is often used in design is...

  17. Analog superconducting quantum simulator for Holstein polarons

    Science.gov (United States)

    Mei, Feng; Stojanović, Vladimir M.; Siddiqi, Irfan; Tian, Lin

    2013-12-01

    We propose an analog quantum simulator for the Holstein molecular-crystal model based on a superconducting circuit QED system in the dispersive regime. By varying the driving field on the superconducting resonators, one can access both the adiabatic and antiadiabatic regimes of this model, and the strong electron-phonon coupling required for small-polaron formation can be readily reached. We show that a small-polaron state of arbitrary quasimomentum can be generated by applying a microwave pulse to the resonators. We also show that significant squeezing in the resonator modes can be achieved in the polaron-crossover regime through a measurement-based scheme.

  18. Digital and analogical reality in proteomics investigation.

    Science.gov (United States)

    Urbani, Andrea; Castagnola, Massimo; Fasano, Mauro; Bini, Luca; Modesti, Alessandra; Timperio, Anna Maria; Roncada, Paola

    2013-06-01

    Are protein functions continuous or discretized? Proteomics investigations are starting to address this non-trivial awesome question focusing upon determining the nature of biological molecular relationships. In the following editorial we present a number of experimental studies published in this themed Proteomics Issue demonstrating the development of a new analogical vision for the interpretation of genotype-phenotype relationships. New metrics and languages are evolving, which may complement the insufficiency based on a binary digital interpretation of biological phenomena, providing new tools for the interpretation of large scale-experimental studies.

  19. Unconscious violinists and the use of analogies in moral argument.

    Science.gov (United States)

    Wiland, E

    2000-12-01

    Analogies are the stuff out of which normative moral philosophy is made. Certainly one of the most famous analogies constructed by a philosopher in order to argue for a specific controversial moral conclusion is the one involving Judith Thomson's unconscious violinist. Reflection upon this analogy is meant to show us that abortion is generally not immoral even if the prenatal have the same moral status as the postnatal. This was and still is a controversial conclusion, and yet the analogy does seem to reveal in a very vivid way what makes abortion a reasonable response to a terrible situation. But Thomson's example has frequently been attacked on all sides for not being truly analogous to abortion. Here I develop a brand new analogy that sheds light on the issue with which Thomson was concerned, while at the same time avoiding most of the more serious objections made to her analogy.

  20. Use of analogy in learning physics: The role of representations

    Directory of Open Access Journals (Sweden)

    Noah D. Finkelstein

    2006-07-01

    Full Text Available Previous studies have demonstrated that analogies can promote student learning in physics and can be productively taught to students to support their learning, under certain conditions. We build on these studies to explore the use of analogy by students in a large introductory college physics course. In the first large-scale study of its kind, we demonstrate that different analogies can lead to varied student reasoning. When different analogies were used to teach electromagnetic (EM waves, we found that students explicitly mapped characteristics either of waves on strings or sound waves to EM waves, depending upon which analogy students were taught. We extend these results by investigating how students use analogies. Our findings suggest that representational format plays a key role in the use of analogy.

  1. Semantics, analogy and alternation capacity of syntactic structures

    Directory of Open Access Journals (Sweden)

    Stanojčić Živojin S.

    2013-01-01

    Full Text Available Departing from examples found in the language of Njegoš and later writers from a broader area, and on the theoretical premises of cognitive linguistics as well as on transformational grammar methodology, author is discussing the syntactic and semantic elements that enable the alternations of conjunctions gde, što, kako and da - mutually and with other dependent clauses conjunctions the semantic basis of which are the notions “cause”, “space”, “manner of an action” and “object of an action”. According to author, in the given process, with inner linguistic semantic and analogical factors, the idiolectal experience of speaker / writer (listener / reader and his/her knowledge of language units in the common language of the given society - have the most important role in the event of language perception.

  2. Graphene Quantum Capacitors for High Frequency Tunable Analog Applications.

    Science.gov (United States)

    Moldovan, Clara F; Vitale, Wolfgang A; Sharma, Pankaj; Tamagnone, Michele; Mosig, Juan R; Ionescu, Adrian M

    2016-08-10

    Graphene quantum capacitors (GQC) are demonstrated to be enablers of radio-frequency (RF) functions through voltage-tuning of their capacitance. We show that GQC complements MEMS and MOSFETs in terms of performance for high frequency analog applications and tunability. We propose a CMOS compatible fabrication process and report the first experimental assessment of their performance at microwaves frequencies (up to 10 GHz), demonstrating experimental GQCs in the pF range with a tuning ratio of 1.34:1 within 1.25 V, and Q-factors up to 12 at 1 GHz. The figures of merit of graphene variable capacitors are studied in detail from 150 to 350 K. Furthermore, we describe a systematic, graphene specific approach to optimize their performance and predict the figures of merit achieved if such a methodology is applied.

  3. Analog IC reliability in nanometer CMOS

    CERN Document Server

    Maricau, Elie

    2013-01-01

    This book focuses on modeling, simulation and analysis of analog circuit aging. First, all important nanometer CMOS physical effects resulting in circuit unreliability are reviewed. Then, transistor aging compact models for circuit simulation are discussed and several methods for efficient circuit reliability simulation are explained and compared. Ultimately, the impact of transistor aging on analog circuits is studied. Aging-resilient and aging-immune circuits are identified and the impact of technology scaling is discussed.   The models and simulation techniques described in the book are intended as an aid for device engineers, circuit designers and the EDA community to understand and to mitigate the impact of aging effects on nanometer CMOS ICs.   ·         Enables readers to understand long-term reliability of an integrated circuit; ·         Reviews CMOS unreliability effects, with focus on those that will emerge in future CMOS nodes; ·         Provides overview of models for...

  4. Palytoxin and Analogs: Biological and Ecological Effects

    Directory of Open Access Journals (Sweden)

    Vítor Ramos

    2010-06-01

    Full Text Available Palytoxin (PTX is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems.

  5. Comparison between analog and digital filters

    Directory of Open Access Journals (Sweden)

    Zoltan Erdei

    2010-12-01

    Full Text Available Digital signal processing(DSP is one of the most powerful technologies and will model science and engineering in the 21st century. Revolutionary changes have already been made in different areas of research such as communications, medical imaging, radar and sonar technology, high fidelity audio signal reproducing etc. Each of these fields developed a different signal processing technology with its own algorithms, mathematics and technology, Digital filters are used in two general directions: to separate mixed signals and to restore signals that were compromised in different modes. The objective of this paper is to compare some basic digital filters versus analog filters such as low-pass, high-pass, band-pass filters. Scientists and engineers comprehend that, in comparison with analog filters, digital filters can process the same signal in real-time with broader flexibility. This understanding is considered important to instill incentive for engineers to become interested in the field of DSP. The analysis of the results will be made using dedicated libraries in MATLAB and Simulink software, such as the Signal Processing Toolbox.

  6. AFEII Analog Front End Board Design Specifications

    Energy Technology Data Exchange (ETDEWEB)

    Rubinov, Paul; /Fermilab

    2005-04-01

    This document describes the design of the 2nd iteration of the Analog Front End Board (AFEII), which has the function of receiving charge signals from the Central Fiber Tracker (CFT) and providing digital hit pattern and charge amplitude information from those charge signals. This second iteration is intended to address limitations of the current AFE (referred to as AFEI in this document). These limitations become increasingly deleterious to the performance of the Central Fiber Tracker as instantaneous luminosity increases. The limitations are inherent in the design of the key front end chips on the AFEI board (the SVXIIe and the SIFT) and the architecture of the board itself. The key limitations of the AFEI are: (1) SVX saturation; (2) Discriminator to analog readout cross talk; (3) Tick to tick pedestal variation; and (4) Channel to channel pedestal variation. The new version of the AFE board, AFEII, addresses these limitations by use of a new chip, the TriP-t and by architectural changes, while retaining the well understood and desirable features of the AFEI board.

  7. Merging Galaxy Clusters: Analysis of Simulated Analogs

    Science.gov (United States)

    Nguyen, Jayke; Wittman, David; Cornell, Hunter

    2018-01-01

    The nature of dark matter can be better constrained by observing merging galaxy clusters. However, uncertainty in the viewing angle leads to uncertainty in dynamical quantities such as 3-d velocities, 3-d separations, and time since pericenter. The classic timing argument links these quantities via equations of motion, but neglects effects of nonzero impact parameter (i.e. it assumes velocities are parallel to the separation vector), dynamical friction, substructure, and larger-scale environment. We present a new approach using n-body cosmological simulations that naturally incorporate these effects. By uniformly sampling viewing angles about simulated cluster analogs, we see projected merger parameters in the many possible configurations of a given cluster. We select comparable simulated analogs and evaluate the likelihood of particular merger parameters as a function of viewing angle. We present viewing angle constraints for a sample of observed mergers including the Bullet cluster and El Gordo, and show that the separation vectors are closer to the plane of the sky than previously reported.

  8. Photonically assisted analog-to-digital conversion

    Science.gov (United States)

    Asuri, Bhushan Shanti

    The evolutionary progress in electronic Analog to Digital Converters is not sufficient to meet the needs of high- speed, digital, radar receivers. We present a wide variety of techniques to address the problem of ultra- fast A/D conversion using photonics. We propose architectures, which map an electrical signal into the optical wavelength domain. The wavelength-mapped signal can then be manipulated using dispersive optic devices. The basic architectures based on time-wavelength mapping are Time Stretch, Wavelength Division Sampling and Wavelength Sampling and Shuffle. TS and WSS allow us to process segments of the electrical signal. This segment- interleaving is a potential novel strength of photonic analog-to-digital conversion techniques. The important experimental achievements include demonstration of 130 Gsa/s 7ENOB TSADC, with filtering over 1 GHZ and 30 Gsa/s, 4ENOB TSADC system over 4GHz. In the case of WDS systems we have shown 12 Gsa/s continuous time WDS system and 100 Gsa/s WDS system. We have also performed preliminary experiments to show the viability of a 16 Gsa/s, 4 channel WSS system with time aperture of 500ns. The important analytical milestones include a link level analysis of dynamic range of TSADC. We have also analyzed the effect of fiber dispersion (β2 and β3) on TSADC and the effect of mismatch in sample interleaved systems.

  9. Amygdalin analogs for the treatment of psoriasis.

    Science.gov (United States)

    Perez, Juan J

    2013-05-01

    Psoriasis is one of the most prevalent immune-mediated illness worldwide. The disease can still only be managed rather than cured, so treatments are aimed at clearing skin lesions and preventing their recurrence. Several treatments are available depending on the extent of the psoriatic lesion. Among the topical treatments corticostereoids, vitamin D3 analogs and retinoids are commonly used. However, these treatments may have adverse effects in the long term. Conversely, systemic conventional treatments include immunosuppresors such as cyclosporin or methotrexate associated with high toxicity levels. Biologicals are alternative therapeutical agents introduced in the last 10 years. These include fusion proteins or monoclonal antibodies designed to inhibit the action of specific cytokines or to prevent T-lymphocyte activation. However, due to recent knowledge on the etiology of the disease, diverse new small molecules have appeared as promising alternatives for the treatment of psoriasis. Among them, inhibitors of JAK3, inhibitors of PDE 4 and amygdalin analogs. The latter are promising small molecules presently in preclinical studies which are the object of the present report.

  10. Metaphor and analogy in everyday problem solving.

    Science.gov (United States)

    Keefer, Lucas A; Landau, Mark J

    2016-11-01

    Early accounts of problem solving focused on the ways people represent information directly related to target problems and possible solutions. Subsequent theory and research point to the role of peripheral influences such as heuristics and bodily states. We discuss how metaphor and analogy similarly influence stages of everyday problem solving: Both processes mentally map features of a target problem onto the structure of a relatively more familiar concept. When individuals apply this structure, they use a well-known concept as a framework for reasoning about real world problems and candidate solutions. Early studies found that analogy use helped people gain insight into novel problems. More recent research on metaphor goes further to show that activating mappings has subtle, sometimes surprising effects on judgment and reasoning in everyday problem solving. These findings highlight situations in which mappings can help or hinder efforts to solve problems. WIREs Cogn Sci 2016, 7:394-405. doi: 10.1002/wcs.1407 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

  11. An Investigation of Reasoning by Analogy in Schizophrenia and Autism Spectrum Disorder

    Directory of Open Access Journals (Sweden)

    Daniel C Krawczyk

    2014-08-01

    Full Text Available Relational reasoning ability relies upon by both cognitive and social factors. We compared analogical reasoning performance in healthy controls (HC to performance in individuals with Autism Spectrum Disorder (ASD, and individuals with schizophrenia (SZ. The experimental task required participants to find correspondences between drawings of scenes. Participants were asked to infer which item within one scene best matched a relational item within the second scene. We varied relational complexity, presence of distraction, and type of objects in the analogies (living or non-living items. We hypothesized that the cognitive differences present in SZ would reduce relational inferences relative to ASD and HC. We also hypothesized that both SZ and ASD would show lower performance on living item problems relative to HC due to lower social function scores. Overall accuracy was higher for HC relative to SZ, consistent with prior research. Across groups, higher relational complexity reduced analogical responding, as did the presence of non-living items. Separate group analyses revealed that the ASD group was less accurate at making relational inferences in problems that involved mainly non-living items and when distractors were present. The SZ group showed differences in problem type similar to the ASD group. Additionally, we found significant correlations between social cognitive ability and analogical reasoning, particularly for the SZ group. These results indicate that differences in cognitive and social abilities impact the ability to infer analogical correspondences along with numbers of relational elements and types of objects present in the problems.

  12. A Systematic Evaluation of Analogs and Automated Read ...

    Science.gov (United States)

    Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a data-poor (target) chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified based on structural similarity. Although much guidance has been published for read-across, practical principles for the identification and evaluation of the scientific validity of source analogs remains lacking. This case study explores how well 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) are able to identify analogs for read-across and predict Estrogen Receptor (ER) binding activity for a specific class of chemicals: hindered phenols. For each target chemical, analogs were selected using each descriptor set with two cut-offs: (1) Minimum Tanimoto similarity (range 0.1 - 0.9), and (2) Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. The analogs were subsequently filtered using: (1) physchem properties (LogKow & Molecular Volume), and (2) number of literature sources as a marker for the quality of the experimental data. A majority vote prediction was made for each target phenol by reading-across from the closest N analogs. The data set comprised 462 hindered phenols and 257 non-hindered phenols. The results demonstrate that: (1) The concordance in ER activity rises with increasing similarity,

  13. A Systematic Evaluation of Analogs for the Read-across ...

    Science.gov (United States)

    Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a target data-poor chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified based on structural similarity. Although much guidance has been published for read-across, practical guiding principles for the identification and evaluation of the scientific validity of source analogs, which is a critical step in deriving a robust read-across prediction, remains largely lacking.This case study explores the extent to which 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) and their combinations are able to identify valid analogs for reading across Estrogen Receptor (ER) activity for a specific class of chemicals: hindered phenols. For each target chemical, two sets of analogs (hindered and non-hindered phenols) were selected using each descriptor set with two cut-offs: (1). Minimum Tanimoto similarity (range 0.1 - 0.9), and (2). Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. Subsequently, the analogs were filtered using physchem properties (LogKow & Molecular Volume) and the resultant agreement between each target-analog pair was evaluated. The data set comprised 462 hindered phenols and 296 non-hindered phenols. The results demonstrate that: (1). The concordance in ER activity r

  14. Analog Electronic Filters Theory, Design and Synthesis

    CERN Document Server

    Dimopoulos, Hercules G

    2012-01-01

    Filters are essential subsystems in a huge variety of electronic systems. Filter applications are innumerable; they are used for noise reduction, demodulation, signal detection, multiplexing, sampling, sound and speech processing, transmission line equalization and image processing, to name just a few. In practice, no electronic system can exist without filters. They can be found in everything from power supplies to mobile phones and hard disk drives and from loudspeakers and MP3 players to home cinema systems and broadband Internet connections. This textbook introduces basic concepts and methods and the associated mathematical and computational tools employed in electronic filter theory, synthesis and design.  This book can be used as an integral part of undergraduate courses on analog electronic filters. Includes numerous, solved examples, applied examples and exercises for each chapter. Includes detailed coverage of active and passive filters in an independent but correlated manner. Emphasizes real filter...

  15. Four-gate transistor analog multiplier circuit

    Science.gov (United States)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  16. Atwood and Poggendorff: an insightful analogy

    Science.gov (United States)

    Coelho, R. L.; Borges, P. F.; Karam, R.

    2016-11-01

    Atwood’s treatise, in which the Atwood machine appears, was published in 1784. About 70 years later, Poggendorff showed experimentally that the weight of an Atwood machine is reduced when it is brought to motion. In the present paper, a twofold connection between this experiment and the Atwood machine is established. Firstly, if the Poggendorff apparatus is taken as an ideal one, the equations of motion of the apparatus coincide with the equations of motion of the compound Atwood machine. Secondly, if the Poggendorff apparatus, which works as a lever, is rebalanced, the equations of this equilibrium provide us with the solution for a compound Atwood machine with the same bodies. This analogy is pedagogically useful because it illustrates a common strategy to transform a dynamic in a static situation improving students’ comprehension of Newton’s laws and equilibrium.

  17. Noise in time-discrete analog filters

    Science.gov (United States)

    Kroemer, B.; Mueller, R.; Stegherr, M.; Klar, H.; Ulbrich, W.

    The most important noise sources in time-discrete analog filters which can be monolithically integrated as CCD and switched-capacitor structures are described. In CCD filters, these sources are thermal kTC noise of the input and output levels and unloading processes at the surface attraction sites. Attainable signal-to-noise ratios and optimization possibilities are stated. For SC filters, the most important noise sources are kTC noise and l/f noise. On-chip clock jitter noise can be suppressed by differential processing. The present measurements on integrated MOS switching transistors with small areas confirm the thermal kTC noise limit and show that there is no additional l/f contribution to the noise from the switches. For the integrator, good agreement is obtained between theory and experiment when an operational amplifier with finite unity-gain frequency is included.

  18. Antifungal Activity of Homoaconitate and Homoisocitrate Analogs

    Directory of Open Access Journals (Sweden)

    Sławomir Milewski

    2012-11-01

    Full Text Available Thirteen structural analogs of two initial intermediates of the L-a-aminoadipate pathway of L-lysine biosynthesis in fungi have been designed and synthesized, including fluoro- and epoxy-derivatives of homoaconitate and homoisocitrate. Some of the obtained compounds exhibited at milimolar range moderate enzyme inhibitory properties against homoaconitase and/or homoisocitrate dehydrogenase of Candida albicans. The structural basis for homoisocitrate dehydrogenase inhibition was revealed by molecular modeling of the enzyme-inhibitor complex. On the other hand, the trimethyl ester forms of some of the novel compounds exhibited antifungal effects. The highest antifungal activity was found for trimethyl trans-homoaconitate, which inhibited growth of some human pathogenic yeasts with minimal inhibitory concentration (MIC values of 16–32 mg/mL.

  19. Principles of digital and analog communications

    CERN Document Server

    Gibson, Jerry D

    1993-01-01

    This textbook for the first course in communications covers analog and digital systems and emphasizes digital communications. It covers data transmission, signal space, optimal receivers, and pulse code modulation, and includes readable treatments of coded modulation and continuous phase modulation. Advanced mathematics is kept to a minimum-Fourier series, Fourier transforms, linear systems, random variables, and stochastic process are described thoroughly. It includes data compression of speech and images and a full chapter coverage of information theory, rate distortion theory and coded modulation. It relates digital communications theory to current practice and covers digital communications over band-width constrained channels, including pulse shaping and equilization. -- Dieser Text bezieht sich auf eine vergriffene oder nicht verfügbare Ausgabe dieses Titels.

  20. Analog noise reduction in enzymatic logic gates.

    Science.gov (United States)

    Melnikov, Dmitriy; Strack, Guinevere; Pita, Marcos; Privman, Vladimir; Katz, Evgeny

    2009-07-30

    In this work, we demonstrate both experimentally and theoretically that the analog noise generation by a single enzymatic logic gate can be dramatically reduced to yield gate operation with virtually no input noise amplification. We demonstrate that when a cosubstrate with a much smaller affinity than the primary substrate is used, a negligible increase in the noise output from the logic gate is obtained, as compared to the input noise level. Our general theoretical conclusions were confirmed by experimental realizations of the AND logic gate based on the enzyme horseradish peroxidase using hydrogen peroxide as the substrate, with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) or ferrocyanide as cosubstrates with vastly different rate constants.

  1. Integrated Circuits for Analog Signal Processing

    CERN Document Server

    2013-01-01

      This book presents theory, design methods and novel applications for integrated circuits for analog signal processing.  The discussion covers a wide variety of active devices, active elements and amplifiers, working in voltage mode, current mode and mixed mode.  This includes voltage operational amplifiers, current operational amplifiers, operational transconductance amplifiers, operational transresistance amplifiers, current conveyors, current differencing transconductance amplifiers, etc.  Design methods and challenges posed by nanometer technology are discussed and applications described, including signal amplification, filtering, data acquisition systems such as neural recording, sensor conditioning such as biomedical implants, actuator conditioning, noise generators, oscillators, mixers, etc.   Presents analysis and synthesis methods to generate all circuit topologies from which the designer can select the best one for the desired application; Includes design guidelines for active devices/elements...

  2. Analogical transfer in the THOG task.

    Science.gov (United States)

    Koenig, Cynthia S; Griggs, Richard A

    2004-04-01

    The influences of surface and structural similarity on analogical transfer were examined with 318 undergraduate participants in four experiments using Needham and Amado's (1995) Pythagoras THOG problem as the source problem and Wason's standard abstract THOG task as the target problem. In Experiments 1-3, systematic changes in surface similarity between the source and target problems were introduced by changing the named exemplar, the dimensional values, and the dimensions, respectively, in the target problem. Significant transfer was obtained in all three experiments. In Experiment 4, we explored the basis of this transfer by examining three versions of the Pythagoras THOG problem, factorially combining its facilitating features as source problems. Results indicated that the inclusion of a hypothesis generation request was necessary for significant transfer. The implications of our findings for using transfer versus facilitation as the performance criterion for deductive reasoning are considered.

  3. Analogy between fluid cavitation and fracture mechanics

    Science.gov (United States)

    Hendricks, R. C.; Mullen, R. L.; Braun, M. J.

    1983-01-01

    When the stresses imposed on a fluid are sufficiently large, rupture or cavitation can occur. Such conditions can exist in many two-phase flow applications, such as the choked flows, which can occur in seals and bearings. Nonspherical bubbles with large aspect ratios have been observed in fluids under rapid acceleration and high shear fields. These bubbles are geometrically similar to fracture surface patterns (Griffith crack model) existing in solids. Analogies between crack growth in solid and fluid cavitation are proposed and supported by analysis and observation (photographs). Healing phenomena (void condensation), well accepted in fluid mechanics, have been observed in some polymers and hypothesized in solid mechanics. By drawing on the strengths of the theories of solid mechanics and cavitation, a more complete unified theory can be developed.

  4. Synthesis and Evaluation of Desmethyl Azumamide Analogs

    DEFF Research Database (Denmark)

    Maolanon, Alex

    associated with various types of cancer and HDACs have therefore been a target in the development of anticancer drugs. So far, two HDAC inhibitors have been approved by the food and drug administration (FDA) and several compounds are in clinical trials. Macrocyclic HDAC inhibitors are interesting compounds...... interactions with the large cap group. The natural compounds have been used as an inspiration to synthesize new HDAC inhibitors. A small structure activity relationship (SAR) study was conducted in collaboration with Jesper S. Villadsen. Aromatic substituents in the cyclic peptide were explored, while...... and Peter Fristrup. Compared to the natural compounds, the 3Dstructure of the scaffold in the azumamide analogs were similar. Although a conclusion was not found, the preliminary docking results indicated favorable lipophilic interaction with the methyl group in the azumamides. Largazole is another...

  5. Optical analog-to-digital converter

    Science.gov (United States)

    Evanchuk, Vincent L. (Inventor)

    1984-01-01

    A method and apparatus for converting the intensity of an unknown optical signal (B) into an electrical signal in digital form utilizes two elongated optical attenuators (11, 13), one for the unknown optical signal from a source (10) and one for a known optical signal (A) from a variable source (12), a plurality of photodetectors (e.g., 17, 18) along each attenuator for detecting the intensity of the optical signals, and a plurality of comparators (e.g., 21) connected to the photodetectors in pairs to determine at what points being compared the attenuated known signal equals the attenuated unknown signal. The intensity of the unknown relative to the known is thus determined by the output of a particular comparator. That output is automatically encoded to a relative intensity value in digital form through a balancing feedback control (24) and encoder (23). The digital value may be converted to analog form in a D-to-A converter (27) and used to vary the source of the known signal so that the attenuated intensity of the known signal at a predetermined point (comparator 16) equals the attenuated intensity of the unknown signal at the predetermined point of comparison. If the known signal is then equal to the unknown, there is verification of the analog-to-digital conversion being complete. Otherwise the output of the comparator indicating equality at some other point along the attenuators will provide an output which is encoded and added, through an accumulator comprised of a register (25) and an adder (26), to a previous relative intensity value thereby to further vary the intensity of the known signal source. The steps are repeated until full conversion is verified.

  6. The Corfu Landslide: Analog to Giant Landslides on Mars

    Science.gov (United States)

    Lewis, S. W.; Baker, V. R.

    1984-01-01

    In an analog to the great landslides of the Vales Marineris, Mars, a detailed study was made of the Corfu Landslide in south-central Washington. This prehistoric slide is located on the northern flank of the Saddle Mountains, southwest of Othello, Washington. The slide covers a 13 square km area centered on section 11 of T.15N., R.27E., Willamette Meridian, adjacent to the Corfu townsite. Approximately 1 cubic km of material is involved in sliding that was probably initiated by Missoula flooding through the Channeled Scabland. It is concluded that there were four primary factors involved in the initiation of the Corfu landsliding: (1) A slip surface was present at the right orientation; (2) Glacial flooding undercut the slope; (3) Wetter climatic conditions prevailed during that time period; and (4) Some seismic vibrations, known to occur locally, probably acted as a trigger. These factors show that special conditions were required in conjunction to produce landsliding. Studies in progress of the Vales Marieneris suggest that the same factors probably contributed to landsliding there.

  7. Manning’s equation and two-dimensional flow analogs

    Science.gov (United States)

    Hromadka, T. V., II; Whitley, R. J.; Jordan, N.; Meyer, T.

    2010-07-01

    SummaryTwo-dimensional (2D) flow models based on the well-known governing 2D flow equations are applied to floodplain analysis purposes. These 2D models numerically solve the governing flow equations simultaneously or explicitly on a discretization of the floodplain using grid tiles or similar tile cell geometry, called "elements". By use of automated information systems such as digital terrain modeling, digital elevation models, and GIS, large-scale topographic floodplain maps can be readily discretized into thousands of elements that densely cover the floodplain in an edge-to-edge form. However, the assumed principal flow directions of the flow model analog, as applied across an array of elements, typically do not align with the floodplain flow streamlines. This paper examines the mathematical underpinnings of a four-direction flow analog using an array of square elements with respect to floodplain flow streamlines that are not in alignment with the analog's principal flow directions. It is determined that application of Manning's equation to estimate the friction slope terms of the governing flow equations, in directions that are not coincident with the flow streamlines, may introduce a bias in modeling results, in the form of slight underestimation of flow depths. It is also determined that the maximum theoretical bias, occurs when a single square element is rotated by about 13°, and not 45° as would be intuitively thought. The bias as a function of rotation angle for an array of square elements follows approximately the bias for a single square element. For both the theoretical single square element and an array of square elements, the bias as a function of alignment angle follows a relatively constant value from about 5° to about 85°, centered at about 45°. This bias was first noted about a decade prior to the present paper, and the magnitude of this bias was estimated then to be about 20% at about 10° misalignment. An adjustment of Manning's n is

  8. [Reasoning by analogy in chemical history: fallacies and guidelines].

    Science.gov (United States)

    Snelders, H A

    1994-01-01

    In chemistry (and natural science in general) reasoning in terms of analogy may be of great practical value as well as of theoretical significance. At the same, however, the use of analogy is risky and the results are uncertain. In alchemy and iatrochemistry analogies between the living and the non-living nature have been carried too far. At the end of the 19th century an analogy was drawn between chemical phenomena and the Darwinian theory of evolution. Another example of an overexaggerated analogy can be found in Lavoisier's theory of acids, where oxygen was considered to be the general principle of acidity. Reasoning by analogy is mostly based on an inner conviction. It leads to provisional predictions in such cases where the required facts are not, or incompletely, at our disposal.

  9. 23rd workshop on Advances in Analog Circuit Design

    CERN Document Server

    Baschirotto, Andrea; Makinwa, Kofi

    2015-01-01

    This book is based on the 18 tutorials presented during the 23rd workshop on Advances in Analog Circuit Design.  Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, serving as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.    • Includes coverage of high-performance analog-to-digital and digital to analog converters, integrated circuit design in scaled technologies, and time-domain signal processing; • Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; • Presents material in a tutorial-based format.

  10. Bridging analog and digital video in the surgical setting.

    Science.gov (United States)

    Miron, Hagai; Blumenthal, Eytan Z

    2003-10-01

    Editing surgical videos requires a basic understanding of key technical issues, especially when transforming from analog to digital media. These issues include an understanding of compression-decompression (eg, MPEGs), generation quality loss, video formats, and compression ratios. We introduce basic terminology and concepts related to analog and digital video, emphasizing the process of converting analog video to digital files. The choice of hardware, software, and formats is discussed, including advantages and drawbacks. Last, we provide an inexpensive hardware-software solution.

  11. Synthesis and anti-inflammatory activity of phenylbutenoid dimer analogs

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Soo; Fang, Yuan Ying; Park, Hae Eil [Kangwon National University, Chuncheon (Korea, Republic of)

    2015-06-15

    Several phenylbutenoid dimer (PBD) analogs were synthesized and evaluated for their inhibitory activities against nitric oxide (NO) production and TNF-α release. The PBD analogs were synthesized via Diels–Alder and subsequent Schlosser reactions as key steps. Among the tested compounds, two analogs (8c, 8f) exhibited much stronger inhibitory activity against LPS-stimulated NO production and TNF-α release in RAW 264.7 cells than that of wogonin.

  12. Analog circuit design a tutorial guide to applications and solutions

    CERN Document Server

    Williams, Jim

    2011-01-01

    * Covers the fundamentals of linear/analog circuit and system design to guide engineers with their design challenges. * Based on the Application Notes of Linear Technology, the foremost designer of high performance analog products, readers will gain practical insights into design techniques and practice. * Broad range of topics, including power management tutorials, switching regulator design, linear regulator design, data conversion, signal conditioning, and high frequency/RF design. * Contributors include the leading lights in analog design, Robert Dobkin, Jim Willia

  13. CRC handbook of neurohypophyseal hormone analogs. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Jost, K.; Lebl, M.; Brtnik, F.

    1987-01-01

    This book is discussed in two parts. The Part 1 discusses the: Prohormones and Hormonogens of Neuro-hypophyseal Hormones, Analogs with Inhibitory properties. Analogs with Dissociated and/or High activities. Introduction. Uterotonic Activity. Galactogogic Activity. Pressor Activity. Antidiuretic Activity. References. Part 2 discusses the Other Important Activities. CNS Activities. Corticotropin- and ..beta..-Entriuretic Action. Natriferic Action. References. Practical Use in Human and Veterinary Medicine. Introduction. Methyloxytocin. Deamino-Oxytocin. Cargutocin. Glypressin. Octapressin. Desmopressin. Analogs Clinically Tried But Not Introduced into Production and Routine Clinical Practice. References. Tables of Analogs and Index.

  14. Creative Analogy Use in a Heterogeneous Design Team

    DEFF Research Database (Denmark)

    Christensen, Bo; Ball, Linden J.

    2016-01-01

    We integrated two research traditions – one focusing on analogical reasoning, the other on knowledge sharing – with the aim of examining how designers' unique knowledge backgrounds can fuel analogy-based creativity. The present dataset afforded a unique opportunity to pursue this aim since...... associated with increased epistemic uncertainty, perhaps because domain experts appreciate the challenge of mapping such analogies between domains. Our findings support claims from the knowledge-sharing literature for a direct route from knowledge diversity through analogical reasoning to novel idea...

  15. 25th workshop on Advances in Analog Circuit Design

    CERN Document Server

    Harpe, Pieter; Makinwa, Kofi

    2017-01-01

    This book is based on the 18 tutorials presented during the 25th workshop on Advances in Analog Circuit Design. Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including low-power and energy-efficient analog electronics, with specific contributions focusing on the design of continuous-time sigma-delta modulators, automotive electronics, and power management. This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.

  16. Analog-digital converters for industrial applications including an introduction to digital-analog converters

    CERN Document Server

    Ohnhäuser, Frank

    2015-01-01

    This book offers students and those new to the topic of analog-to-digital converters (ADCs) a broad introduction, before going into details of the state-of-the-art design techniques for SAR and DS converters, including the latest research topics, which are valuable for IC design engineers as well as users of ADCs in applications. The book then addresses important topics, such as correct connectivity of ADCs in an application, the verification, characterization and testing of ADCs that ensure high-quality end products. Analog-to-digital converters are the central element in any data processing system and regulation loops such as modems or electrical motor drives. They significantly affect the performance and resolution of a system or end product. System development engineers need to be familiar with the performance parameters of the converters and understand the advantages and disadvantages of the various architectures. Integrated circuit development engineers have to overcome the problem of achieving high per...

  17. Is the link from working memory to analogy causal? No analogy improvements following working memory training gains.

    Science.gov (United States)

    Richey, J Elizabeth; Phillips, Jeffrey S; Schunn, Christian D; Schneider, Walter

    2014-01-01

    Analogical reasoning has been hypothesized to critically depend upon working memory through correlational data, but less work has tested this relationship through experimental manipulation. An opportunity for examining the connection between working memory and analogical reasoning has emerged from the growing, although somewhat controversial, body of literature suggests complex working memory training can sometimes lead to working memory improvements that transfer to novel working memory tasks. This study investigated whether working memory improvements, if replicated, would increase analogical reasoning ability. We assessed participants' performance on verbal and visual analogy tasks after a complex working memory training program incorporating verbal and spatial tasks. Participants' improvements on the working memory training tasks transferred to other short-term and working memory tasks, supporting the possibility of broad effects of working memory training. However, we found no effects on analogical reasoning. We propose several possible explanations for the lack of an impact of working memory improvements on analogical reasoning.

  18. How strategists really think. Tapping the power of analogy.

    Science.gov (United States)

    Gavetti, Giovanni; Rivkin, Jan W

    2005-04-01

    Leaders tend to be so immersed in the specifics of strategy that they rarely stop to think how much of their reasoning is done by analogy. As a result, they miss useful insights that psychologists and other scientists have generated about analogies' pitfalls. Managers who pay attention to their own analogical thinking will make better strategic decisions and fewer mistakes. Charles Lazarus was inspired by the supermarket when he founded Toys R Us; Intel promoted its low-end chips to avoid becoming like U.S. Steel; and Circuit City created CarMax because it saw the used-car market as analogous to the consumer-electronics market. Each example displays the core elements of analogical reasoning: a novel problem or a new opportunity, a specific prior context that managers deem to be similar in its essentials, and a solution that managers can transfer from its original setting to the new one. Analogical reasoning is a powerful tool for sparking breakthrough ideas. But dangers arise when analogies are built on surface similarities (headlong diversification based on loose analogies played a role in Enron's collapse, for instance). Psychologists have discovered that it's all too easy to overlook the superficiality of analogies. The situation is further complicated by people's tendency to hang on to beliefs even after contrary evidence comes along (a phenomenon known as anchoring) and their tendency to seek only the data that confirm their beliefs (an effect known as the confirmation bias). Four straightforward steps can improve a management team's odds of using an analogy well: Recognize the analogy and identify its purpose; thoroughly understand its source; determine whether the resemblance is more than superficial; and decide whether the original strategy, properly translated, will work in the target industry.

  19. San Francisco Volcanic Field, Arizona, as AN Analog for Lunar and Martian Surface Exploration

    Science.gov (United States)

    Young, K. E.; Hodges, K.; Eppler, D.; Horz, F.; Lofgren, G. E.; Hurtado, J. M.; Desert Rats Science Team

    2010-12-01

    similar to several sites on both the Moon and Mars, and it is logistically easy for some 120 ground support staff and their equipment to access and operate in, there are several factors that need to be considered when evaluating the fidelity of SFVF and the D-RATS activities and analogs. For example, the lack of conventional sedimentary processes on the Moon detracts from its scientific fidelity as a lunar analog. While lava flows on Mars seem to have similar morphology and outcrop patterns to SFVF, there are no lunar analogs where volcanic flows lie on top of sedimentary outcrops. This presentation will discuss both the merits and limitations of this analog site.

  20. MEDIA PEMBELAJARAN ANALOG OSCILLATOR VIRTUAL LABOLATORY

    Directory of Open Access Journals (Sweden)

    Aji Widhi Wibowo

    2016-01-01

    Full Text Available The purpose of this research is to design and implement a Virtual Labolatory Materials Signal Processing Sub discussion 'Oscillator' Analog as Newspapers. Developers using the model Sutopo Ariesto Hadi (2003 as a method to produce the product. Consists of six stages: concept, design, material collecting, assembly, testing and distribution. This results in the development of Virtual media Labolatory with material 'Oscillator' with the results of 4 (four practicum digital oscillator, namely (1 Oscillator Wien Bridge, (2 Colpitts oscillator, (3 Oscillator Hartley and (4 astable multivibrator. Another result is that a user be jobsheet practicum. There are two types, namely: (1 jobsheet grip lecturers and (2 jobsheet for students. In Jobsheet there is a short book that contains the Manual on procedures for the use of virtual labolatory when practical and anatomical description of the product. Virtual Labolatory consists of the initial page (flash scren, the main page (home, pages and pages about the developer's lab referring to the story board. There are four (4 test are: (1 the truth polarity capacitor, (2 the connection (wiring, (3 mode frequency and time in the meter frequency

  1. Radiolabeled somatostatin analogs in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Thakur, M.L.; Kolan, H.; Li, J.; Wiaderkiewicz, R.; Pallela, V.R.; Duggaraju, R.; Schally, A.V

    1997-01-01

    Vapreotide (RC-160), a somatostatin analog, was labeled with {sup 99m}Tc by a direct method and also by using CPTA [1,4,8,11-tetraazacyclotetradecane] as a bifunctional chelating agent. The labeled compounds were evaluated in nude mice bearing experimental human prostate cancers. In these studies, {sup 111}In-DTPA-D-Phe-Octreotide ({sup 111}In-DTPA-octreotide) served as a standard and {sup 99m}Tc-oxytocin as a receptor-non-specific control. {sup 99m}Tc-octreotide was also used. The 24 htumor uptake of {sup 99m}Tc-RC-160 was nearly 400% higher, (p < 0.05), than that of {sup 111}In-DTPA-octreotide and diminished upon receptor blocking. In all tissues except the kidneys, the uptake of {sup 99m}Tc-RC-160 was also higher than that of {sup 111}In-DTPA-octreotide. The uptake of {sup 99m}Tc-RC-160 was influenced by the amount of peptide injected and the best tumor/muscle and tumor/blood ratios were obtained when only one {mu}g of the peptide (200 Ci/mmol) was administered.

  2. Amino acid analogs for tumor imaging

    Science.gov (United States)

    Goodman, Mark M.; Shoup, Timothy

    1998-09-15

    The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

  3. HERE, THERE, AND EVERYWHEREPublic Science Through Analogy

    Science.gov (United States)

    Arcand, Kimberly K.

    2014-06-01

    Here, There, and Everywhere (HTE) is a program that consists of a series of exhibitions, posters, and supporting hands-on activities that utilize analogies in the teaching of science, engineering, and technology to provide multi-generational and family-friendly content in English and Spanish to small community centers, libraries, under-resourced small science centers. The purpose of the program is to connect crosscutting science content (in Earth, atmospheric and planetary sciences and astrophysics) with everyday phenomena. By using different modes of content delivery, from physical exhibits and handouts,to interpretive stations, facilitated activities for educators, and online resources, HTE helps to demonstrate the universality of physical laws and the connection between our everyday world and the universe as a whole to members of the public who may not identify strongly with science. HTE is part of a series of public science projects created and developed by the Education and Public Outreach group at the Chandra X-ray Center. The authors discuss how HTE fits into the lineage of public science outreach that aims to engage the greater public in non-traditional venues for science learning and appreciation, as well as what might be learned about the participants of such projects.

  4. Intracranial Fluid Redistribution During a Spaceflight Analog

    Science.gov (United States)

    Koppelmans, Vincent; Pasternak, Ofer; Bloomberg, Jacob J.; De Dios, Yiri E.; Wood, Scott J.; Riascos, Roy; Reuter-Lorenz, Patrica A.; Kofman, Igor S.; Mulavara, Ajitkumar P.; Seidler, Rachael D.

    2017-01-01

    The neural correlates of spaceflight-induced sensorimotor impairments are unknown. Head down-tilt bed rest (HDBR) serves as a microgravity analog because it mimics the headward fluid shift and limb unloading of spaceflight. We investigated focal brain white matter (WM) changes and fluid shifts during 70 days of 6 deg HDBR in 16 subjects who were assessed pre (2x), during (3x), and post-HDBR (2x). Changes over time were compared to those in control subjects (n=12) assessed four times over 90 days. Diffusion MRI was used to assess WM microstructure and fluid shifts. Free-Water Imaging, derived from diffusion MRI, was used to quantify the distribution of intracranial extracellular free water (FW). Additionally, we tested whether WM and FW changes correlated with changes in functional mobility and balance measures. HDBR resulted in FW increases in fronto-temporal regions and decreases in posterior-parietal regions that largely recovered by two weeks post-HDBR. WM microstructure was unaffected by HDBR. FW decreased in the post-central gyrus and precuneus. We previously reported that gray matter increases in these regions were associated with less HDBR-induced balance impairment, suggesting adaptive structural neuroplasticity. Future studies are warranted to determine causality and underlying mechanisms.

  5. Natural Analog Studies at Pena Blanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    A.M. Simmons

    2005-07-11

    The significance of the Pena Blanca uranium deposits in the State of Chihuahua, Mexico as potential natural analogs for a nuclear waste repository in unsaturated welded tuff was first recognized in the 1980s. In the 1970s, the Pena Blanca region was a major target of uranium exploration and exploitation by the Mexican government. Since then the Nopal I uranium deposit has been studied extensively by researchers in the U.S., Mexico, and Europe. The Nopal I deposit represents an environment similar to that of the proposed high-level radioactive waste repository at Yucca Mountain in many ways. Both are located in semi-arid regions. Both are located in Tertiary rhyolitic tuffs overlying carbonate rocks that have been subjected to basin and range-style tectonic deformation. Both are located in a chemically oxidizing, unsaturated zone 200 m or more above the water table. The alteration of uraninite to secondary minerals at Nopal I may be similar to the alteration of uranium fuel rods in this type of setting. Investigations at Nopal I and in the surrounding Sierra Pena Blanca have included detailed outcrop mapping, hydrologic and isotopic studies of flow and transport, studies of mineral alteration, modeling, and performance assessment.

  6. Interstellar and Planetary Analogs in the Laboratory

    Science.gov (United States)

    Salama, Farid

    2013-01-01

    We present and discuss the unique capabilities of the laboratory facility, COSmIC, that was developed at NASA Ames to investigate the interaction of ionizing radiation (UV, charged particles) with molecular species (neutral molecules, radicals and ions) and carbonaceous grains in the Solar System and in the Interstellar Medium (ISM). COSmIC stands for Cosmic Simulation Chamber, a laboratory chamber where interstellar and planetary analogs are generated, processed and analyzed. It is composed of a pulsed discharge nozzle (PDN) expansion that generates a free jet supersonic expansion in a plasma cavity coupled to two ultrahigh-sensitivity, complementary in situ diagnostics: a cavity ring down spectroscopy (CRDS) system for photonic detection and a Reflectron time-of-flight mass spectrometer (ReTOF-MS) for mass detection. This setup allows the study of molecules, ions and solids under the low temperature and high vacuum conditions that are required to simulate some interstellar, circumstellar and planetary physical environments providing new fundamental insights on the molecular level into the processes that are critical to the chemistry in the ISM, circumstellar and planet forming regions, and on icy objects in the Solar System. Recent laboratory results that were obtained using COSmIC will be discussed, in particular the progress that have been achieved in monitoring in the laboratory the formation of solid particles from their gas-phase molecular precursors in environments as varied as circumstellar outflow and planetary atmospheres.

  7. Cisplatin Analogs Confer Protection against Cyanide Poisoning.

    Science.gov (United States)

    Nath, Anjali K; Shi, Xu; Harrison, Devin L; Morningstar, Jordan E; Mahon, Sari; Chan, Adriano; Sips, Patrick; Lee, Jangwoen; MacRae, Calum A; Boss, Gerry R; Brenner, Matthew; Gerszten, Robert E; Peterson, Randall T

    2017-05-18

    Cisplatin holds an illustrious position in the history of chemistry most notably for its role in the virtual cure of testicular cancer. Here we describe a role for this small molecule in cyanide detoxification in vivo. Cyanide kills organisms as diverse as insects, fish, and humans within seconds to hours. Current antidotes exhibit limited efficacy and are not amenable to mass distribution requiring the development of new classes of antidotes. The binding affinity of the cyanide anion for the positively charged metal platinum is known to create an extremely stable complex in vitro. We therefore screened a panel of diverse cisplatin analogs and identified compounds that conferred protection from cyanide poisoning in zebrafish, mice, and rabbits. Cumulatively, this discovery pipeline begins to establish the characteristics of platinum ligands that influence their solubility, toxicity, and efficacy, and provides proof of concept that platinum-based complexes are effective antidotes for cyanide poisoning. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Resonant Tunneling Analog-To-Digital Converter

    Science.gov (United States)

    Broekaert, T. P. E.; Seabaugh, A. C.; Hellums, J.; Taddiken, A.; Tang, H.; Teng, J.; vanderWagt, J. P. A.

    1995-01-01

    As sampling rates continue to increase, current analog-to-digital converter (ADC) device technologies will soon reach a practical resolution limit. This limit will most profoundly effect satellite and military systems used, for example, for electronic countermeasures, electronic and signal intelligence, and phased array radar. New device and circuit concepts will be essential for continued progress. We describe a novel, folded architecture ADC which could enable a technological discontinuity in ADC performance. The converter technology is based on the integration of multiple resonant tunneling diodes (RTD) and hetero-junction transistors on an indium phosphide substrate. The RTD consists of a layered semiconductor hetero-structure AlAs/InGaAs/AlAs(2/4/2 nm) clad on either side by heavily doped InGaAs contact layers. Compact quantizers based around the RTD offer a reduction in the number of components and a reduction in the input capacitance Because the component count and capacitance scale with the number of bits N, rather than by 2 (exp n) as in the flash ADC, speed can be significantly increased, A 4-bit 2-GSps quantizer circuit is under development to evaluate the performance potential. Circuit designs for ADC conversion with a resolution of 6-bits at 25GSps may be enabled by the resonant tunneling approach.

  9. Natural CO2 Analogs for Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Scott H. Stevens; B. Scott Tye

    2005-07-31

    The report summarizes research conducted at three naturally occurring geologic CO{sub 2} fields in the US. The fields are natural analogs useful for the design of engineered long-term storage of anthropogenic CO{sub 2} in geologic formations. Geologic, engineering, and operational databases were developed for McElmo Dome in Colorado; St. Johns Dome in Arizona and New Mexico; and Jackson Dome in Mississippi. The three study sites stored a total of 2.4 billion t (46 Tcf) of CO{sub 2} equivalent to 1.5 years of power plant emissions in the US and comparable in size with the largest proposed sequestration projects. The three CO{sub 2} fields offer a scientifically useful range of contrasting geologic settings (carbonate vs. sandstone reservoir; supercritical vs. free gas state; normally pressured vs. overpressured), as well as different stages of commercial development (mostly undeveloped to mature). The current study relied mainly on existing data provided by the CO{sub 2} field operator partners, augmented with new geochemical data. Additional study at these unique natural CO{sub 2} accumulations could further help guide the development of safe and cost-effective design and operation methods for engineered CO{sub 2} storage sites.

  10. 47 CFR 74.705 - TV broadcast analog station protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false TV broadcast analog station protection. 74.705... EXPERIMENTAL RADIO, AUXILIARY, SPECIAL BROADCAST AND OTHER PROGRAM DISTRIBUTIONAL SERVICES Low Power TV, TV Translator, and TV Booster Stations § 74.705 TV broadcast analog station protection. (a) The TV broadcast...

  11. Stereoselective synthesis of nicotinamide beta-riboside and nucleoside analogs.

    Science.gov (United States)

    Franchetti, Palmarisa; Pasqualini, Michela; Petrelli, Riccardo; Ricciutelli, Massimo; Vita, Patrizia; Cappellacci, Loredana

    2004-09-20

    The beta-anomers of N-ribofuranosylnicotine-3-carboxamide (beta-NAR) and its nicotinic acid analog (beta-NaR) were obtained by stereoselective synthesis via glycosylation of the presilylated bases under Vorbruggen's protocol. A NAR analog, methylated in position 3 of the ribosylic moiety, is also reported.

  12. Can metaphors and analogies improve communication with seriously ill patients?

    Science.gov (United States)

    Casarett, David; Pickard, Amy; Fishman, Jessica M; Alexander, Stewart C; Arnold, Robert M; Pollak, Kathryn I; Tulsky, James A

    2010-03-01

    It is not known how often physicians use metaphors and analogies, or whether they improve patients' perceptions of their physicians' ability to communicate effectively. Therefore, the objective of this study was to determine whether the use of metaphors and analogies in difficult conversations is associated with better patient ratings of their physicians' communication skills. Cross-sectional observational study of audio-recorded conversations between patients and physicians. Three outpatient oncology practices. Ninety-four patients with advanced cancer and 52 physicians. None. Conversations were reviewed and coded for the presence of metaphors and analogies. Patients also completed a 6-item rating of their physician's ability to communicate. In a sample of 101 conversations, coders identified 193 metaphors and 75 analogies. Metaphors appeared in approximately twice as many conversations as analogies did (65/101, 64% versus 31/101, 31%; sign test p < 0.001). Conversations also contained more metaphors than analogies (mean 1.6, range 0-11 versus mean 0.6, range 0-5; sign rank test p < 0.001). Physicians who used more metaphors elicited better patient ratings of communication (rho = 0.27; p = 0.006), as did physicians who used more analogies (Spearman rho = 0.34; p < 0.001). The use of metaphors and analogies may enhance physicians' ability to communicate.

  13. Analog capacitance ROM with IGFET bucket-brigade shift register

    DEFF Research Database (Denmark)

    Bruun, Erik; Olesen, Ole

    1975-01-01

    A new type of monolithic analog read-out memory is described. It consists of a memory element and associated on-chip readout circuitry. The memory can be used for storing sample values of time-varying analog signals. The memory element is a matrix of MOS capacitors, preprogrammed in size by a spe...

  14. Molecular interactions between (--epigallocatechin gallate analogs and pancreatic lipase.

    Directory of Open Access Journals (Sweden)

    Shihui Wang

    Full Text Available The molecular interactions between pancreatic lipase (PL and four tea polyphenols (EGCG analogs, like (--epigallocatechin gallate (EGCG, (--gallocatechin gallate (GCG, (--epicatechin gallate (ECG, and (--epigallocatechin (EC, were studied from PL activity, conformation, kinetics and thermodynamics. It was observed that EGCG analogs inhibited PL activity, and their inhibitory rates decreased by the order of EGCG>GCG>ECG>EC. PL activity at first decreased rapidly and then slowly with the increase of EGCG analogs concentrations. α-Helix content of PL secondary structure decreased dependent on EGCG analogs concentration by the order of EGCG>GCG>ECG>EC. EGCG, ECG, and EC could quench PL fluorescence both dynamically and statically, while GCG only quenched statically. EGCG analogs would induce PL self-assembly into complexes and the hydrodynamic radii of the complexes possessed a close relationship with the inhibitory rates. Kinetics analysis showed that EGCG analogs non-competitively inhibited PL activity and did not bind to PL catalytic site. DSC measurement revealed that EGCG analogs decreased the transition midpoint temperature of PL enzyme, suggesting that these compounds reduced PL enzyme thermostability. In vitro renaturation through urea solution indicated that interactions between PL and EGCG analogs were weak and non-covalent.

  15. Analysis of Attention and Analogical Reasoning in Children of Poverty

    Science.gov (United States)

    Weatherholt, Tara N.; Harris, Ruby C.; Burns, Barbara M.; Clement, Catherine

    2006-01-01

    This study examined the relationship between specific attentional aspects of processing capacity and analogical reasoning in children from low-income families. 77 children aged 48-77 (M = 56.7) months were assessed on an analogical reasoning task (matrices subtest of the Kaufman Brief Intelligence Test) and on computerized attention tasks designed…

  16. Analogy as a means of theoretical adoption of pedagogical disciplines

    Directory of Open Access Journals (Sweden)

    Solovcova Irina A.

    2006-01-01

    Full Text Available The paper considers an application of analogy in the initial-teacher training as a tool of approaching pedagogical disciplines. The author proposes a classification of pedagogical analogies which provides choices of the most efficient model for a specific didactic situation. The article clarifies the model of the theoretical approach to pedagogical disciplines through active use of analogy, which contributes to a higher efficiency in a teacher and student interaction. The model consists of three stages: training (the stage of acquiring analogy model, the analytical stage (acquisition of pedagogical concepts, phenomena and systems through the application of analogy, and the stage of self-realization (the application of analogy method in students’ scientific-research activities considering external and internal didactic conditions which transform analogy from a teaching method into a tool for the acquisition of pedagogical disciplines. The author demonstrates that the application of analogy has a positive effect not only on the acquisition of pedagogical knowledge (especially methodic and the development of heuristic skills in students, but also on motivation for the study of pedagogical disciplines (cognitive aspect and professional pedagogical activity (formation of an individual-pedagogical attitude. .

  17. Small, low power analog-to-digital converter

    Science.gov (United States)

    Dunn, R. D.; Fullerton, D. H.

    1968-01-01

    A small, low-power, high-speed, 8-bit analog-to-digital converter using silicon chip integrated circuits is suitable for use in airborne test data systems. The successive approximation method of analog-to-digital conversion is used to generate the digital output.

  18. Using Analogies to Prevent Misconceptions about Chemical Equilibrium

    Science.gov (United States)

    Sahin Pekmez, Esin

    2010-01-01

    The main purpose of this study was to find the effectiveness of using analogies to prevent misconceptions about chemical equilibrium. Nineteen analogies, which were based on dynamic aspects of chemical equilibrium and application of Le Chatelier's principle, were developed. The participations of this study consisted of 11th grade students (n: 151)…

  19. Tren-based Analogs of Bacillibactin: Structure and Stability1

    Science.gov (United States)

    Dertz, Emily A.; Xu, Jide; Raymond, Kenneth N.

    2011-01-01

    Synthetic analogs were designed to highlight the effect of the glycine moiety of bacillibactin on the overall stability of the ferric complex as compared to synthetic analogs of enterobactin. Insertion of a variety of amino acids to catecholamide analogs based on a Tren (tris(2-aminoethyl)amine) backbone increased the overall acidity of the ligands, causing an enhancement of the stability of the resulting ferric complex as compared to TRENCAM. Solution thermodynamic behavior of these siderophores and their synthetic analogs was investigated through potentiometric and spectrophotometric titrations. X-ray crystallography, circular dichroism, and molecular modeling were used to determine the chirality and geometry of the ferric complexes of bacillibactin and its analogs. In contrast to the Tren scaffold, addition of a glycine to the catechol chelating arms causes an inversion of the trilactone backbone, resulting in opposite chiralities of the two siderophores and a destabilization of the ferric complex of bacillibactin compared to ferric enterobactin. PMID:16813410

  20. NASA HRP Immunology Discipline - Use of Terrestrial Analogs

    Science.gov (United States)

    Crucian, Brian

    2014-01-01

    Due to the cost and operational constraints, as well as technical implementation limitations, it is desirous to perform relevant space physiology investigations first in terrestrial 'space analogs'. This is particularly true for initial investigations, which may then provide appropriate focus for subsequent flight investigations, or for mechanistic investigations that simply cannot be performed during spaceflight. Appropriate analog choice is extremely important. There are a wide variety of terrestrial space analogs, each relevant to a particular physiological discipline (or disciplines) and each with a particular fidelity (or lack thereof) to spaceflight, and each with unique operational constraints. The HRP Immunology Discipline is tasked with managing the HRP Risk concerning clinical risk for Astronaut crews related to spaceflight-associated immune dysregulation. Such dysregulation has been documented to occur during spaceflight, and found to persist for the duration of a 6-month ISS mission. Studies continue to characterize the onorbit phenomenon, but it generally consists of diminished immunocyte function, dysregulated cytokine profiles, and persistent herpesvirus reactivation. Causes are thought to synergistically include microgravity, psychological or physiological stress, radiation, and/or circadian misalignment. An appropriate terrestrial analog for immune dysregulation would replicate as many of these influences as possible. Such analogs may include clinostat or bioreactor cell culture (microgravity), hindlimb suspension (stress, fluid shifts, hypokinesis), or human deployment to remote or extreme environments (isolation, stress, circadian). Also, the laboratory setting may be used as an analog, or to augment analogs, such as sleep deprivation/misalignment or human centrifugation to replicate gravitational stress. As an appropriate example of a NASA Disciplines use of Terrestrial space analogs, this talk will discuss spaceflight associated immune

  1. Neurotrophic peptide aldehydes: Solid phase synthesis of fellutamide B and a simplified analog

    OpenAIRE

    Schneekloth, John S.; John L Sanders; Hines, John; Crews, Craig M.

    2006-01-01

    A combination of solid phase and solution phase synthetic methods have been used to complete the total synthesis of the neurotrophic lipopeptide aldehyde fellutamide B (2). The β-hydroxy aliphatic tail was prepared by regioselective reductive opening of a cyclic sulfate, and later coupled to a solid phase resin. The synthetic compound was then examined in cytotoxicity and nerve growth factor (NGF) induction assays. A simplified analog of fellutamide B also showed activity.

  2. Relaxant and anti-inflammatory effect of two thalidomide analogs as PDE-4 inhibitors in pregnant rat uterus

    Science.gov (United States)

    Muñoz-Pérez, Víctor Manuel; Ponce-Monter, Héctor; Ortiz, Mario I.

    2017-01-01

    The aim of this study was to evaluate the relaxant and anti-inflammatory effects of two thalidomide analogs as phosphodiesterase-4 (PDE-4) inhibitors in pregnant rat uterus. Uteri from Wistar female rats were isolated at 19 day of pregnancy. Uterine samples were used in functional studies to evaluate the inhibitory effects of the thalidomide analogs, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4NO2PDPMe) and methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4APDPMe), on prostaglandin-F2α (PGF2α)-induced phasic, K+-induced tonic, and Ca2+-induced contractions. Accumulation of cAMP was quantified in uterine homogenates by ELISA. Anti-inflammatory effect was assessed by using ELISA for determination of the pro-inflammatory cytokines tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and anti-inflammatory IL-10, from uterine explants stimulated with lipopolysaccharide (LPS). Nifedipine, forskolin and rolipram were used as positive controls where required. Both thalidomide analogs induced a significant inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. Nifedipine and forskolin were more potent than the analogs to inhibit the uterine contractility, but these were more potent than rolipram, and 4APDPMe was equieffective to nifedipine. Thalidomide analogs increased uterine cAMP-levels in a concentration-dependent manner. The LPS-induced TNFα and IL-1β uterine secretion was diminished in a concentration-dependent fashion by both analogs, whereas IL-10 secretion was increased significantly. The thalidomide analogs induced utero-relaxant and anti-inflammatory effects, which were associated with the increased cAMP levels as PDE-4 inhibitors in the pregnant rat uterus. Such properties place these thalidomide analogs as potentially safe and effective tocolytic agents in a field that urgently needs improved pharmacological treatments, as in cases of preterm labor. PMID:28706457

  3. Remote Sensing and Quantization of Analog Sensors

    Science.gov (United States)

    Strauss, Karl F.

    2011-01-01

    This method enables sensing and quantization of analog strain gauges. By manufacturing a piezoelectric sensor stack in parallel (physical) with a piezoelectric actuator stack, the capacitance of the sensor stack varies in exact proportion to the exertion applied by the actuator stack. This, in turn, varies the output frequency of the local sensor oscillator. The output, F(sub out), is fed to a phase detector, which is driven by a stable reference, F(sub ref). The output of the phase detector is a square waveform, D(sub out), whose duty cycle, t(sub W), varies in exact proportion according to whether F(sub out) is higher or lower than F(sub ref). In this design, should F(sub out) be precisely equal to F(sub ref), then the waveform has an exact 50/50 duty cycle. The waveform, D(sub out), is of generally very low frequency suitable for safe transmission over long distances without corruption. The active portion of the waveform, t(sub W), gates a remotely located counter, which is driven by a stable oscillator (source) of such frequency as to give sufficient digitization of t(sub W) to the resolution required by the application. The advantage to this scheme is that it negates the most-common, present method of sending either very low level signals (viz. direct output from the sensors) across great distances (anything over one-half meter) or the need to transmit widely varying higher frequencies over significant distances thereby eliminating interference [both in terms of beat frequency generation and in-situ EMI (electromagnetic interference)] caused by ineffective shielding. It also results in a significant reduction in shielding mass.

  4. Ice megadunes on Mars: analogy with Antarctica

    Science.gov (United States)

    Herny, Clémence; Massé, Marion; Bourgeois, Olivier; Carpy, Sabrina; Le Mouélic, Stéphane; Appéré, Thomas; Smith, Isaac; Spiga, Aymeric; Rodriguez, Sébastien

    2014-05-01

    Mass and energy balance of ice sheets are driven by complex interactions between the atmosphere and the cryosphere. Feedbacks between katabatic winds and the cryosphere may lead to the formation of sedimentation waves, so-called megadunes, at the surface of ice sheets. These have been first described in Antarctica. Here we use topographic data, optical images, and spectroscopic data acquired by Mars orbiters. We show that the surface of the Martian North Polar Cap displays two superimposed sets of sedimentation waves with differing wavelengths. These sedimentation waves have similarities with Antarctic ice megadunes regarding their surface morphology, texture, grain size, and internal stratigraphic architecture. Their shallow-dipping upwind sides, their tops and the intervening troughs are covered by young ice and occasional sastrugi fields, indicative of net accumulation. On the other hand, their steep-dipping downwind sides either expose exhumed layers of dusty old ice or correspond to smooth surfaces of coarse-grained ice, indicative of net ablation or reduced net accumulation associated with sublimation and metamorphism. These surface characteristics and the internal stratigraphic architecture revealed by radar sounding are consistent with the interpretation that both sets of Martian sedimentation waves grow and migrate upwind in response to the development of periodic accumulation/ablation patterns controlled by katabatic winds. The smaller waves, characterized by reduced net accumulation on their downwind sides, are probably analogous to the Antarctic megadunes that have been described so far. On the other hand, a terrestrial equivalent remains to be discovered for the larger ones, characterized by net ablation on their downwind sides. The recognition of these sedimentation waves provides the basis for the development of a common model of ice/wind interaction at the surface of Martian and terrestrial ice sheets and for future investigations on the respective

  5. The linguistic analogy: motivations, results, and speculations.

    Science.gov (United States)

    Dwyer, Susan; Huebner, Bryce; Hauser, Marc D

    2010-07-01

    Inspired by the success of generative linguistics and transformational grammar, proponents of the linguistic analogy (LA) in moral psychology hypothesize that careful attention to folk-moral judgments is likely to reveal a small set of implicit rules and structures responsible for the ubiquitous and apparently unbounded capacity for making moral judgments. As a theoretical hypothesis, LA thus requires a rich description of the computational structures that underlie mature moral judgments, an account of the acquisition and development of these structures, and an analysis of those components of the moral system that are uniquely human and uniquely moral. In this paper we present the theoretical motivations for adopting LA in the study of moral cognition: (a) the distinction between competence and performance, (b) poverty of stimulus considerations, and (c) adopting the computational level as the proper level of analysis for the empirical study of moral judgment. With these motivations in hand, we review recent empirical findings that have been inspired by LA and which provide evidence for at least two predictions of LA: (a) the computational processes responsible for folk-moral judgment operate over structured representations of actions and events, as well as coding for features of agency and outcomes; and (b) folk-moral judgments are the output of a dedicated moral faculty and are largely immune to the effects of context. In addition, we highlight the complexity of the interfaces between the moral faculty and other cognitive systems external to it (e.g., number systems). We conclude by reviewing the potential utility of the theoretical and empirical tools of LA for future research in moral psychology. Copyright © 2009 Cognitive Science Society, Inc.

  6. De Analogía a Digitalia

    Directory of Open Access Journals (Sweden)

    Dr. Xaime Fandiño Alonso

    2001-01-01

    ía, creatividad y contenidos.ABSTRACTThe transition towards binary-based technology has unleashed dramatic changes that in the last decade have affected the different stages involved in an audiovisual production: from scripting and creating a project, through the various technological procedures of the actual production process to its final distribution.The remains of the analogical era are finally sinking under a seemingly unstoppable wave of constantly evolving new digital environments.The new hardware devices used in this field are mainly prototypes. An ever evolving market, the constant arising of new competitors, newborn joint-ventures and a myriad of related facts force technology providers to keep a pace of constant updating in a mad race of fierce competition.The old system which implied one machine for each process is increasingly becoming a memory of the past. Today new devices are being launched at such a speed that the old technological approach which dealt with mechanical appliances like magnetoscopes, closed platforms and linear recording are already bound for extinction.It’s only natural then that the sacred cows of the industry fear for their position. Big and small are elusive concepts in this new audiovisual frenzy. Its almost daily routine to read about big audiovisual corporations announcing mergers, buy-outs or the acquisition of a stake in new and small creativity and development firms built from scratch by young entrepreneurs out of the blue.The digital era is drawing a heavy curtain that luckily leaves behind an analogical era in which the ownership of the costly means of production was the most important card in the game. The artist could only exercise its art if access to the professional team and technical equipment required for an audiovisual work was granted by its proprietors.Today, digital means new systems with far more productive environments which besides are user-friendly and cost only a small fraction of the old hardware.Right now, with

  7. Eye Movements Reveal Optimal Strategies for Analogical Reasoning.

    Science.gov (United States)

    Vendetti, Michael S; Starr, Ariel; Johnson, Elizabeth L; Modavi, Kiana; Bunge, Silvia A

    2017-01-01

    Analogical reasoning refers to the process of drawing inferences on the basis of the relational similarity between two domains. Although this complex cognitive ability has been the focus of inquiry for many years, most models rely on measures that cannot capture individuals' thought processes moment by moment. In the present study, we used participants' eye movements to investigate reasoning strategies in real time while solving visual propositional analogy problems (A:B::C:D). We included both a semantic and a perceptual lure on every trial to determine how these types of distracting information influence reasoning strategies. Participants spent more time fixating the analogy terms and the target relative to the other response choices, and made more saccades between the A and B items than between any other items. Participants' eyes were initially drawn to perceptual lures when looking at response choices, but they nonetheless performed the task accurately. We used participants' gaze sequences to classify each trial as representing one of three classic analogy problem solving strategies and related strategy usage to analogical reasoning performance. A project-first strategy, in which participants first extrapolate the relation between the AB pair and then generalize that relation for the C item, was both the most commonly used strategy as well as the optimal strategy for solving visual analogy problems. These findings provide new insight into the role of strategic processing in analogical problem solving.

  8. Eye Movements Reveal Optimal Strategies for Analogical Reasoning

    Directory of Open Access Journals (Sweden)

    Michael S. Vendetti

    2017-06-01

    Full Text Available Analogical reasoning refers to the process of drawing inferences on the basis of the relational similarity between two domains. Although this complex cognitive ability has been the focus of inquiry for many years, most models rely on measures that cannot capture individuals' thought processes moment by moment. In the present study, we used participants' eye movements to investigate reasoning strategies in real time while solving visual propositional analogy problems (A:B::C:D. We included both a semantic and a perceptual lure on every trial to determine how these types of distracting information influence reasoning strategies. Participants spent more time fixating the analogy terms and the target relative to the other response choices, and made more saccades between the A and B items than between any other items. Participants' eyes were initially drawn to perceptual lures when looking at response choices, but they nonetheless performed the task accurately. We used participants' gaze sequences to classify each trial as representing one of three classic analogy problem solving strategies and related strategy usage to analogical reasoning performance. A project-first strategy, in which participants first extrapolate the relation between the AB pair and then generalize that relation for the C item, was both the most commonly used strategy as well as the optimal strategy for solving visual analogy problems. These findings provide new insight into the role of strategic processing in analogical problem solving.

  9. Spaceflight Sensorimotor Analogs: Simulating Acute and Adaptive Effects

    Science.gov (United States)

    Taylor, Laura C.; Harm, Deborah L.; Kozlovskaya, Inessa; Reschke, Millard F.; Wood, Scott J.

    2009-01-01

    Adaptive changes in sensorimotor function during spaceflight are reflected by spatial disorientation, motion sickness, gaze destabilization and decrements in balance, locomotion and eye-hand coordination that occur during and following transitions between different gravitational states. The purpose of this study was to conduct a meta-synthesis of data from spaceflight analogs to evaluate their effectiveness in simulating adaptive changes in sensorimotor function. METHODS. The analogs under review were categorized as either acute analogs used to simulate performance decrements accompanied with transient changes, or adaptive analogs used to drive sensorimotor learning to altered sensory feedback. The effectiveness of each analog was evaluated in terms of mechanisms of action, magnitude and time course of observed deficits compared to spaceflight data, and the effects of amplitude and exposure duration. RESULTS. Parabolic flight has been used extensively to examine effects of acute variation in gravitational loads, ranging from hypergravity to microgravity. More recently, galvanic vestibular stimulation has been used to elicit acute postural, locomotor and gaze dysfunction by disrupting vestibular afferents. Patient populations, e.g., with bilateral vestibular loss or cerebellar dysfunction, have been proposed to model acute sensorimotor dysfunction. Early research sponsored by NASA involved living onboard rotating rooms, which appeared to approximate the time course of adaptation and post-exposure recovery observed in astronauts following spaceflight. Exposure to different bed-rest paradigms (6 deg head down, dry immersion) result in similar motor deficits to that observed following spaceflight. Shorter adaptive analogs have incorporated virtual reality environments, visual distortion paradigms, exposure to conflicting tilt-translation cues, and exposure to 3Gx centrifugation. As with spaceflight, there is considerable variability in responses to most of the analogs

  10. MaMBA - a functional Moon and Mars Base Analog

    Science.gov (United States)

    Heinicke, C.; Foing, B.

    2017-09-01

    Despite impressive progress in robotic exploration of celestial bodies, robots are believed to never reach the effectiveness and efficiency of a trained human. Consequently, ESA proposes to build an international Moon Village in roughly 15 years and NASA plans for the first manned mission to Mars shortly after. One of the challenges still remaining is the need for a shelter, a habitat which allows human spacefarers to safely live and work on the surface of a celestial body. Although a number of prototype habitats has been built during the last decades and inhabited for various durations (e.g. MDRS, FMARS, HI-SEAS, M.A.R.S.), these habitats are typically equipped for studies on human factors and would not function in an extraterrestrial environment. Project MaMBA (Moon and Mars Base Analog) aims to build the first functional habitat based on the lessons learned from intermediate and long duration missions at the mentioned habitats. The habitat will serve for testing technologies like life support, power systems, and interplanetary communi­cation. Special attention will be given to the develop­ment of the geoscience laboratory module. Crews will live and work inside the habitat to ensure its functionality.

  11. Triazole-containing monophosphate mRNA cap analogs as effective translation inhibitors.

    Science.gov (United States)

    Piecyk, Karolina; Lukaszewicz, Maciej; Darzynkiewicz, Edward; Jankowska-Anyszka, Marzena

    2014-10-01

    Synthetic analogs of the 5' end of mRNA (cap structure) are widely used in molecular studies on mechanisms of cellular processes such as translation, intracellular transport, splicing, and turnover. The best-characterized cap binding protein is translation initiation factor 4E (eIF4E). Recognition of the mRNA cap by eIF4E is a critical, rate-limiting step for efficient translation initiation and is considered a major target for anticancer therapy. Here, we report a facile methodology for the preparation of N2-triazole-containing monophosphate cap analogs and present their biological evaluation as inhibitors of protein synthesis. Five analogs possessing this unique hetero-cyclic ring spaced from the m7-guanine of the cap structure at a distance of one or three carbon atoms and/or additionally substituted by various groups containing the benzene ring were synthesized. All obtained compounds turned out to be effective translation inhibitors with IC50 similar to dinucleotide triphosphate m(7)GpppG. As these compounds possess a reduced number of phosphate groups and, thereby, a negative charge, which may support their cell penetration, this type of cap analog might be promising in terms of designing new potential therapeutic molecules. In addition, an exemplary dinucleotide from a corresponding mononucleotide containing benzyl substituted 1,2,3-triazole was prepared and examined. The superior inhibitory properties of this analog (10-fold vs. m(7)GpppG) suggest the usefulness of such compounds for the preparation of mRNA transcripts with high translational activity. © 2014 Piecyk et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  12. Josephson junction analog and quasiparticle-pair current

    DEFF Research Database (Denmark)

    Bak, Christen Kjeldahl; Pedersen, Niels Falsig

    1973-01-01

    A close analogy exists between a Josephson junction and a phase-locked loop. A new type of electrical analog based on this principle is presented. It is shown that the inclusion in this analog of a low-pass filter gives rise to a current of the same form as the Josephson quasiparticle-pair curren....... A simple picture of the quasiparticle-pair current, which gives the right dependences, is obtained by assuming a junction cutoff frequency to be at the energy gap. ©1973 American Institute of Physics...

  13. High-speed digital-to-analog converter concepts

    Science.gov (United States)

    Schmidt, Christian; Kottke, Christoph; Jungnickel, Volker; Freund, Ronald

    2017-01-01

    In today's fiber-optic communication systems, the bandwidth of the photonic components, i.e. modulators and photo diodes, is way greater than that of their electrical counterparts, i.e. digital-to-analog converters (DACs) and analog-to-digital converters (ADCs). In order to increase the transmission capacity, the bandwidth limitations need to be overcome. We review the progress and the recent results in the field of high-speed DACs, which are desirable for software-defined transmitters. Furthermore, we evaluate interleaving concepts regarding their ability to overcome the above mentioned limitations and demonstrate recent experimental results for a bandwidth interleaved DAC with 40 GHz analog electrical bandwidth.

  14. Figure/ground analogy for integrated sustainability & planning

    CSIR Research Space (South Africa)

    Beyers, C

    2006-12-01

    Full Text Available This article proposes a figure ground analogy as alternative way of conceptually integrating sustainability and planning. Within this framework planners are challenged to creatively consider planning practice and thought against a background...

  15. Project Birdseye Aerial Photograph Collection: Digital and Analog Materials

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This collection consists of both analog and digital aerial photographs from Arctic areas in and around Baffin Bay, the Labrador Sea, the Arctic Ocean, the Beaufort...

  16. Development of Venus Balloon Seismology Missions Through Earth Analog Experiments

    Science.gov (United States)

    Krishnamoorthy, S.; Komjathy, A.; Cutts, J. A.; Pauken, M. T.; Garcia, R. F.; Mimoun, D.; Jackson, J. M.; Kedar, S.; Smrekar, S. E.; Hall, J. L.

    2017-11-01

    The study of a planet’s seismic activity is central to the understanding of its internal structure. We discuss advances made through Earth analog testing for performing remote seismology on Venus using balloons floated in the mid-atmosphere.

  17. 22nd Workshop on Advances in Analog Circuit Design

    CERN Document Server

    Makinwa, Kofi; Harpe, Pieter

    2014-01-01

    This book is based on the 18 tutorials presented during the 22nd workshop on Advances in Analog Circuit Design.  Expert designers present readers with information about a variety of topics at the frontier of analog circuit design, including frequency reference, power management for systems-on-chip, and smart wireless interfaces.  This book serves as a valuable reference to the state-of-the-art, for anyone involved in analog circuit research and development.    ·         Provides a state-of-the-art reference in analog circuit design, written by experts from industry and academia; ·         Presents material in a tutorial-based format; ·         Includes coverage of frequency reference, power management for systems-on-chip, and smart wireless interfaces.

  18. The use of analogy in pro-life argumentation

    Directory of Open Access Journals (Sweden)

    Simona Mazilu

    2012-11-01

    Full Text Available The paper is concerned with how analogy is strategically used in pro-life argumentation on abortion. Pragma-dialectics (van Eemeren and Grootendorst 1992 offers a set of critical questions by means of which I will evaluate the use of the argumentation based on a relation of analogy in terms of dialectical soundness. Examining various pro-life texts, I have noticed that the analogies employed remain unexplained. Therefore, despite the apparent similarities between abortion and the German holocaust or slavery, for instance, there are essential differences which are not mentioned. I claim that these analogies mainly have a rhetorical function, to operate what has been called by Micheli (2007: 960 “a transfer of emotional consensus”.

  19. Leibniz y el concepto de analogía

    Directory of Open Access Journals (Sweden)

    Oscar Miguel Esquisabel

    2008-11-01

    Full Text Available In this paper an analysis of the leibnizian applications of conceptof analogy as well as the analogical reasoning is approached. Thus, the analysis tries to show that the leibnizian concept of analogy is based on the idea of structural similarity. As a consequence of such consideration,two basic ways in which Leibniz applies analogical reasoning are examined. The first way has a conjectural character and is rather heuristic, whereas the second constitutes, at least in intention, a kind of demonstrative analogicalreasoning, since it tries to prove its conclusions for a determined theoreticaldomain by applying a transfer principle, which is itself founded on the identity of structural properties.This procedure is exemplified by outlining the leibnizian view on contingent truths. In this way, the paper concludesby pointing out the theoretical relevance of the concept of similarity in theleibnizian thought.

  20. Analog and digital signal analysis from basics to applications

    CERN Document Server

    Cohen Tenoudji, Frédéric

    2016-01-01

    This book provides comprehensive, graduate-level treatment of analog and digital signal analysis suitable for course use and self-guided learning. This expert text guides the reader from the basics of signal theory through a range of application tools for use in acoustic analysis, geophysics, and data compression. Each concept is introduced and explained step by step, and the necessary mathematical formulae are integrated in an accessible and intuitive way. The first part of the book explores how analog systems and signals form the basics of signal analysis. This section covers Fourier series and integral transforms of analog signals, Laplace and Hilbert transforms, the main analog filter classes, and signal modulations. Part II covers digital signals, demonstrating their key advantages. It presents z and Fourier transforms, digital filtering, inverse filters, deconvolution, and parametric modeling for deterministic signals. Wavelet decomposition and reconstruction of non-stationary signals are also discussed...

  1. Highly linear, sensitive analog-to-digital converter

    Science.gov (United States)

    Cox, J.; Finley, W. R.

    1969-01-01

    Analog-to-digital converter converts 10 volt full scale input signal into 13 bit digital output. Advantages include high sensitivity, linearity, low quantitizing error, high resistance to mechanical shock and vibration loads, and temporary data storage capabilities.

  2. Bombesin and Neurotensin Receptor Targeting Using Radiolabeled Peptide Analogs

    NARCIS (Netherlands)

    M. de Visser (Monique)

    2007-01-01

    textabstractSomatostatin receptor-targeting peptides are widely used for imaging and therapy of neuroendocrine tumors. Peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumor patients with radiolabeled somatostatin analogs has resulted in symptomatic improvement, prolonged survival and

  3. Analogy of ISSR and RAPD markers for comparative analysis of ...

    African Journals Online (AJOL)

    Analogy of ISSR and RAPD markers for comparative analysis of genetic diversity among different Jatropha curcas genotypes. S Gupta, M Srivastava, GP Mishra, PK Naik, RS Chauhan, SK Tiwari, M Kumar, R Singh ...

  4. Physical Analog Modeling of Martian Dike-Induced Deformation

    Science.gov (United States)

    Wyrick, D. Y.; Watson-Morris, M. J.; Morris, A. P.

    2012-03-01

    Analog models of dike injection were performed to determine style and magnitude of structural deformation associated with the dike. Primary deformation style is contraction rather than extension, indicating that martian dikes may not create grabens.

  5. Analog self-powered harvester achieving switching pause control to increase harvested energy

    Science.gov (United States)

    Makihara, Kanjuro; Asahina, Kei

    2017-05-01

    In this paper, we propose a self-powered analog controller circuit to increase the efficiency of electrical energy harvesting from vibrational energy using piezoelectric materials. Although the existing synchronized switch harvesting on inductor (SSHI) method is designed to produce efficient harvesting, its switching operation generates a vibration-suppression effect that reduces the harvested levels of electrical energy. To solve this problem, the authors proposed—in a previous paper—a switching method that takes this vibration-suppression effect into account. This method temporarily pauses the switching operation, allowing the recovery of the mechanical displacement and, therefore, of the piezoelectric voltage. In this paper, we propose a self-powered analog circuit to implement this switching control method. Self-powered vibration harvesting is achieved in this study by attaching a newly designed circuit to an existing analog controller for SSHI. This circuit aims to effectively implement the aforementioned new switching control strategy, where switching is paused in some vibration peaks, in order to allow motion recovery and a consequent increase in the harvested energy. Harvesting experiments performed using the proposed circuit reveal that the proposed method can increase the energy stored in the storage capacitor by a factor of 8.5 relative to the conventional SSHI circuit. This proposed technique is useful to increase the harvested energy especially for piezoelectric systems having large coupling factor.

  6. Impact of novel palmitoylated prolactin-eleasing peptide analogs on metabolic changes in mice with diet-induced obesity

    Czech Academy of Sciences Publication Activity Database

    Pražienková, V.; Holubová, M.; Pelantová, H.; Bugáňová, M.; Pirník, Z.; Mikulášková, Barbora; Popelová, A.; Blechová, M.; Haluzík, M.; Železná, B.; Kuzma, M.; Kuneš, Jaroslav; Maletínská, L.

    2017-01-01

    Roč. 12, č. 8 (2017), č. článku e0183449. E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GA15-08679S Institutional support: RVO:67985823 Keywords : food intake regulation * peroxisome proliferation * lipidized analogs Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 2.806, year: 2016

  7. On the analogy of free will and free belief

    OpenAIRE

    Wagner, Verena

    2017-01-01

    Compatibilist methods borrowed from the free will debate are often used to establish doxastic freedom and epistemic responsibility. Certain analogies between the formation of intention and belief make this approach especially promising. Despite being a compatibilist myself in the practical debate, I will argue that compatibilist methods fail to establish doxastic freedom. My rejection is not based on an argument against the analogy of free will and free belief. Rather, I aim at showing that c...

  8. Direct (under) Sampling vs. Analog Downconversion for BPM Electroncs

    CERN Document Server

    Wendt, M

    2014-01-01

    Digital signal processing by means of undersampling the analog signal has become a popular method for acquiring beam position monitor signals. This presentation discusses the technique and its principle limitations, presents today’s technical limits (e.g. in terms of performance of available ADCs), and provides an outlook for the future. It will also try to compare the technique with more tradition analog downmixing and signal processing methods

  9. BERAS ANALOG SEBAGAI PANGAN FUNGSIONAL DENGAN INDEKS GLIKEMIK RENDAH

    Directory of Open Access Journals (Sweden)

    Santi Noviasari

    2016-04-01

    Full Text Available ABSTRACTThe objective of this research was to produce rice analogue as functional food with low glycemic index. The rice was made from white corn and sorghum with additional soybean flour. The physicochemical properties of rice analogue being analysed were resistant starch content, total phenolic content, dietary fiber, color (L*, +a, +b values and whiteness (oHue. Rice analogue was potentially used as functional food indicated by high level of resistant starch 2.59%-3.31%, total phenolic content 0.18-0.25 mg GAE/g sample and dietary fiber 5.35%-6.14%. Rice analogue from white corn with and without soybean flour was further tested for glycemic index. Rice analogue from white corn has 69 GI value, while rice analogue from white corn with 10% soybean flour addition has 50 GI value.Keywords: functional food, glycemic index, rice analogueABSTRAKTujuan penelitian ini adalah untuk mendapatkan beras analog yang berpotensi sebagai pangan fungsional dan bernilai indeks glikemik rendah. Beras analog dibuat dari bahan baku jagung putih dan sorgum dengan penambahan tepung kedelai. Sifat fisiko kimia beras analog yang dianalisis adalah pati resisten, total fenol, serat pangan, warna (nilai L*, +a, +b dan derajat putih (oHue. Beras analog berpotensi sebagai pangan fungsional, yang ditunjukkan dengan tingginya kadar pati resisten yaitu sebanyak 2,59%-3,31%, total fenol sekitar 0,18-0,25 mg GAE/g sampel dan serat pangan antara 5,35%-6,14%. Beras analog berbahan baku jagung putih dengan dan tanpa penambahan kedelai dipilih untuk uji indeks glikemik. Beras analog dari jagung putih memiliki nilai IG 69 sedangkan beras analog dari jagung putih dengan penambahan tepung kedelai 10% memiliki nilai IG 50.Kata kunci: beras analog, indeks glikemik, pangan fungsional

  10. Synthetic analogs of anoplin show improved antimicrobial activities

    DEFF Research Database (Denmark)

    Munk, Jens; Uggerhøj, Lars Erik; Poulsen, Tanja Juul

    2013-01-01

    We present the antimicrobial and hemolytic activities of the decapeptide anoplin and 19 analogs thereof tested against methicillin-resistant Staphylococcus aureus ATCC 33591 (MRSA), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), vancomycin-resistant Enterococcus faecium (ATCC...... that increasing the charge and/or hydrophobicity improves antimicrobial activity and increases hemolytic activity. For each strain tested, we identify at least six anoplin analogs with an improved therapeutic index compared with anoplin, the only exception being Enterococcus faecium, against which only few...

  11. Fluorinated Analogs of Malachite Green: Synthesis and Toxicity

    Directory of Open Access Journals (Sweden)

    Bahram Parvin

    2008-04-01

    Full Text Available A series of fluorinated analogs of malachite green (MG have been synthesizedand their toxicity to Saccharomyces cerevisiae and a human ovarian epithelial cell lineexamined. The toxicity profiles were found to be different for these two species. Twoanalogs, one with 2,4-difluoro substitution and the other with 2-fluoro substitution seem tobe the most promising analogs because they showed the lowest toxicity to the human cells.

  12. Functional neural correlates of fluid and crystallized analogizing.

    Science.gov (United States)

    Geake, John G; Hansen, Peter C

    2010-02-15

    The main aim of this study was to characterize neural correlates of analogizing as a cognitive contributor to fluid and crystallized intelligence. In a previous fMRI study which employed fluid analogy letter strings as criteria in a multiple plausibility design (Geake and Hansen, 2005), two frontal ROIs associated with working memory (WM) load (within BA 9 and BA 45/46) were identified as regions in which BOLD increase correlated positively with a crystallized measure of (verbal) IQ. In this fMRI study we used fluid letter, number and polygon strings to further investigate the role of analogizing in fluid (transformation string completion) and non fluid or crystallized (unique symbol counting) cognitive tasks. The multi stimulus type (letter, number, polygon) design of the analogy strings enabled investigation of a secondary research question concerning the generalizability of fluid analogizing at a neural level. A selective psychometric battery, including the Raven's Progressive Matrices (RPM), measured individual cognitive abilities. Neural activations for the effect of task-fluid analogizing (string transformation plausibility) vs. crystallized analogizing (unique symbol counting)-included bilateral frontal and parietal areas associated with WM load and fronto parietal models of general intelligence. Neural activations for stimulus type differences were mainly confined to visually specific posterior regions. ROI covariate analyses of the psychometric measures failed to find consistent co-relationships between fluid analogizing and the RPM and other subtests, except for the WAIS Digit Symbol subtest in a group of bilateral frontal cortical regions associated with the maintenance of WM load. Together, these results support claims for separate developmental trajectories for fluid cognition and general intelligence as assessed by these psychometric subtests. Copyright 2009 Elsevier Inc. All rights reserved.

  13. POTENTIAL CW AGENTS. TASK 3. ANALOGS OF TETRAHYDROCANNABINOL

    Science.gov (United States)

    The preparation of Adams’ most active tetrehydrocannabinol analog (Formula I, R=1,2-dimethylheptyl), and of synthetic tetrahydrocannabinol (I, R=n...beta-(3,5-dimethoxyphenyl) ethylanine. The pyrons related to tetrahydrocannabinol (II, R=n-amyl) has been reaction with aqueous ammonia to produce a high...amylphenol. An attempt will be made to condense this aminophenol with pulegone to give a nitrogen analog of tetrahydrocannabinol . The synthesis of pulegone from isopulegol has been accomplished.

  14. The Aesthetics and Establishment of Analog Post-Production

    OpenAIRE

    Larkin, George

    2014-01-01

    This dissertation examines the emergence and establishment of analog post-production during the transition to sound. I analyze how the analog post-production system cannibalized the nascent post-production process of silent film, whereby the image from the filmmakers was combined with non-standardized sound produced live in the theater. Multiple forces at the theaters asserted influence over a film's presentation. Exhibitors, for example, created a de facto form of post-production by altering...

  15. Nucleic Acid Base Analog FRET-Pair Facilitating Detailed Structural Measurements in Nucleic Acid Containing Systems

    DEFF Research Database (Denmark)

    Börjesson, Karl; Preus, Søren; El-Sagheer, Afaf

    2009-01-01

    toward detailed studies of the inherent dynamics of nucleic acid structures. Moreover, the placement of FRET-pair chromophores inside the base stack will be a great advantage in studies where other (biomacro)molecules interact with the nucleic acid. Lastly, our study gives possibly the first truly solid...... distances covering up to more than one turn of the DNA duplex. Importantly, we show that the rigid stacking of the two base analogs, and consequently excellent control of their exact positions and orientations, results in a high control of the orientation factor and hence very distinct FRET changes...... as the number of bases separating tCO and tC(nitro) is varied. A set of DNA strands containing the FRET-pair at wisely chosen locations will, thus, make it possible to accurately distinguish distance- from orientation-changes using FRET. In combination with the good nucleobase analog properties, this points...

  16. Dynamic demonstration of diffractive optic analog-to-digital converter scheme.

    Science.gov (United States)

    Galt, Sheila; Magnusson, Anders; Hård, Sverker

    2003-01-10

    Dynamic behavior of an analog-to-digital converter (ADC) based on diffractive optical element(s) (DOE)(s) was studied and found to be in agreement with predictions. The analog signal was translated to an angular deflection of a laser beam by means of an acousto-optic (AO) cell. The number of bits in this experimental demonstration was three, using an eight-element DOE array. The maximum sample rate was found to be 2.5 MS/s, the limiting factor being the transit time for the acoustic wave across the width of the laser beam in the AO cell. The study is intended as a first dynamic demonstration of a proposed ADC scheme previously demonstrated in a quasi-static version. The full potential of the ADC scheme will require the use of a fast tunable diode laser to replace the AO deflection scheme used here.

  17. Evolution of analogical reasoning in children: follow-up from six to eleven years old

    Directory of Open Access Journals (Sweden)

    Luis Fidel Abregú Tueros

    2009-10-01

    Full Text Available The aim of this study is to establish the time and period of development of Analogical Reasoning (AR and evaluate its independence and performance with respect to the age. We performed a longitudinal cohort study of two age groups and six annual follow-up phases from each one (2000-2005, 2001-2006 in six to eleven years-old children in the city of Huanuco (Peru with a sample of 167 children (first stage, and N=121 (sixth stage. The Raven’s progressive matrices test, coloured version, was applied individually without time limits. Results indicate that AR development occurs in a constant and late way from seven to eleven years-old children, and also that there is independence between the ability of AR and the children age. We discuss the importance of knowledge in the relationships between analogies topics, adjusted to the age, as a mediating factor in the development of AR.

  18. Diagnostics Method for Analog Circuits Based on Improved KECA and Minimum Variance ELM

    Science.gov (United States)

    Yuan, Zhijie; He, Yigang; Yuan, Lifen

    2017-09-01

    Kernel entropy component analysis(KECA) is a new method for data transformation and dimensionality reduction. However it is sensitive to a single kernel radius. By analysis of the relation of statistics in the kernel feature space, improved KECA introduces two kernel radii and an adjusting factor to make KECA less sensitive to kernel radius. A method for fault diagnosis of analog circuits based on the combination of improved KECA and minimum variance extreme learning machine(ELM)is presented. Through wavelet decomposition of sampled signals, features are extracted. Improved KECA for feature dimension reduction is used. Then the fault patterns are classified by minimum variance ELM. Case studies on two analog circuits demonstrating our diagnostics method are presented.

  19. Understanding Young Exoplanet Analogs with WISE

    Science.gov (United States)

    Rice, Emily

    We propose to tackle outstanding questions about the fundamental properties of young brown dwarfs, which are atmospheric analogs to massive gas giant exoplanets, using public archive data from the Wide-field Infrared Survey Explorer (WISE) combined with our extensive dataset of optical and near-infrared observations, including spectra, proper motions, and parallaxes. Using WISE data we will construct color-color diagrams, color- magnitude diagrams, and spectral energy distributions for our sample of candidate young brown dwarfs. We will fully characterize the spectral properties of the candidates and evaluate their membership in nearby young moving groups in order to obtain independent age estimates. The practical outcomes of this project will allow the research community to use observed colors and spectra to reliably constrain the properties - including effective temperature, gravity, and dust/cloud properties - of both brown dwarfs and gas giant exoplanets. We will also search for new young brown dwarfs in the WISE archive using colors and proper motions. The expanded sample of young brown dwarfs will be used to create a self-contained feedback loop to identify and address the shortcomings of cool atmosphere models and low-mass evolutionary tracks, both of which are already being used to infer the properties of massive exoplanets. Disentangling the effects of physical parameters on the observed properties of young brown dwarfs is directly relevant to studies of exoplanets. Direct observations of exoplanets are currently very limited, and young brown dwarfs are the laboratories in which we can solve existing problems before the onslaught of new observations from instruments capable of directly imaging exoplanets, including the Gemini Planet Imager, Project 1640 at the Palomar Observatory, SPHERE on the VLT, and the James Webb Space Telescope. This project addresses the goal of the NASA Science Mission Directorate to discover how the universe works; in particular

  20. On analogy as the motivation for grammaticalization

    NARCIS (Netherlands)

    Fischer, O.

    2008-01-01

    The number of phenomena which are gathered together under the term 'grammaticalization' is quite large and in some ways quite diverse. For the different types of grammaticalization similar motivating factors have been suggested, similar principles, clines and hierarchies. Some of Lehmann's

  1. Nitrogen drives the growth of secondary forests in the Amazon: what analogies with temperate and boreal forests?

    Directory of Open Access Journals (Sweden)

    Tonon G

    2007-12-01

    Full Text Available Nitrogen drives the growth of secondary forests in the Amazon: what analogies with temperate and boreal forests? A comment is made on a recent paper published on Nature (Davidson et al. 2007, in which the authors demonstrate that in the young secondary forests in the Amazon a conservative nitrogen cycle prevails and nitrogen is a key factor driving forest growth. Analogies are also discussed with recent findings on the role of nitrogen deposition on the carbon balance of temperate and boreal forests (Magnani et al. 2007.

  2. Adaptive Visual Analog Scales (AVAS): A modifiable software program for the creation, administration, and scoring of visual analog scales

    National Research Council Canada - National Science Library

    Marsh-Richard, Dawn M; Hatzis, Erin S; Mathias, Charles W; Venditti, Nicholas; Dougherty, Donald M

    2009-01-01

    ... visual analog scale formats. The continuous format is a series of individual items that are rated along a solid line and scored as a percentage of distance from one of the two anchors of the rating line...

  3. Cosmogenesis and the tipping pencil analogy

    Science.gov (United States)

    Adler, Ronald J.

    2012-05-01

    We present a toy model and scenario for cosmogenesis which provides an interesting rationale for the spatial flatness of the universe. The basic assumptions are that the cosmological scale factor obeys the standard Friedmann equation of general relativistic cosmology and that the equation is dominated by a cosmological constant term and a curvature term. The dynamics of the universe is then similar to that of a tipping pencil. The scale factor cannot remain at an unstable initial value of zero and must increase according to the uncertainty principle. If it is also assumed that the universe expands at the minimum asymptotic rate consistent with the uncertainty principle, the result is exact spatial flatness, rather than the near flatness obtained in standard inflation theory.

  4. Automated Cell Synthesis of Analog Integrated Circuit Layout Anasyn.

    Science.gov (United States)

    Stanojevich, Bob Srbislav

    This thesis describes a novel model to automate cell generation for the design of analog integrated circuits and the conclusions about important features that such automation should include. This research represents the first attempt to address this problem by analyzing relevant issues of what constitutes an analog cell and how a technique can be implemented to generate these cells automatically. Our motivation for doing this is the critical limitations to circuit performance which arise from cell design. This thesis defines unique construction properties for the layout of some commonly used analog circuit topologies or cells. This thesis defines the physical layout of analog circuit cells beyond simple geometrical description. Each cell is an independent object that can be interfaced and communicated with. This thesis has extended the concept of an analog cell even further by incorporating synthesis rules into the cell definition. These rules are used to dynamically construct the optimized layout that will satisfy many of the options encountered in actual analog circuit design such as area, matching, tolerance, element rationing and parasitic components. This model can construct complex geometric shapes such as common-centroids, waffles, interdigitated, cascode etc. that are optimized at device level with the precise models for parasitic components. Furthermore, Object-Oriented implementation used in this thesis allow for easy integration of this work into other CAD tools. To demonstrate the feasibility and correctness of the ideas described in this thesis, a CAD tool ANASYN has been written. To test and demonstrate the utility and the performance developed, a variety of test cells have been generated. Data presented clearly demonstrate the uniqueness, flexibility, and precision of the analog circuit layout cells implemented in this research thesis. In addition, one test chip and one design chip have been laid out using cells generated by ANASYN and fabricated at

  5. Terrestrial stress analogs for spaceflight associated immune system dysregulation.

    Science.gov (United States)

    Crucian, Brian; Simpson, Richard J; Mehta, Satish; Stowe, Raymond; Chouker, Alexander; Hwang, Shen-An; Actor, Jeffrey K; Salam, Alex P; Pierson, Duane; Sams, Clarence

    2014-07-01

    Recent data indicates that dysregulation of the immune system occurs and persists during spaceflight. Impairment of immunity, especially in conjunction with elevated radiation exposure and limited clinical care, may increase certain health risks during exploration-class deep space missions (i.e. to an asteroid or Mars). Research must thoroughly characterize immune dysregulation in astronauts to enable development of a monitoring strategy and validate any necessary countermeasures. Although the International Space Station affords an excellent platform for on-orbit research, access may be constrained by technical, logistical vehicle or funding limitations. Therefore, terrestrial spaceflight analogs will continue to serve as lower cost, easier access platforms to enable basic human physiology studies. Analog work can triage potential in-flight experiments and thus result in more focused on-orbit studies, enhancing overall research efficiency. Terrestrial space analogs generally replicate some of the physiological or psychological stress responses associated with spaceflight. These include the use of human test subjects in a laboratory setting (i.e. exercise, bed rest, confinement, circadian misalignment) and human remote deployment analogs (Antarctica winterover, undersea, etc.) that incorporate confinement, isolation, extreme environment, physiological mission stress and disrupted circadian rhythms. While bed rest has been used to examine the effects of physical deconditioning, radiation and microgravity may only be simulated in animal or microgravity cell culture (clinorotation) analogs. This article will characterize the array of terrestrial analogs for spaceflight immune dysregulation, the current evidence base for each, and interpret the analog catalog in the context of acute and chronic stress. Published by Elsevier Inc.

  6. Mars Analog Mission: Glacier Simulation AMADEE-15 by Austrian Space Forum

    Science.gov (United States)

    Groemer, Gernot; Losiak, Anna; Soucek, Alexander; Plank, Clemens; Zanardini, Laura; Sejkora, Nina; Sams, Sebastian

    2016-04-01

    Austrian Space Forum: The Austrian Space Forum (OeWF, Österreichisches Weltraum Forum) is a non-profit, citizen-science organization of aerospace specialists and enthusiasts. One of its specialisations is Mars analog research. Analog studies and analog instrument validation supported all planetary surface missions so far [1] and are considered as an effective tool to prepare for future missions to Mars [2,3,4,5,6,7]. Since 2006, OeWF has conducted 11 Mars analog field campaigns in diverse locations that represented: 1) average current Mars conditions (the Mars Desert Research Station (MDRS) in Utah in 2006 [8] and the Northern Sahara near Erfoud, Morocco in 2013 [9]); 2) the early and wet Mars (analog site of Rio Tinto Spain in 2011 [10]); and 3) subsurface exploration (Dachstein Ice Caves in 2012). During these campaigns, 68 experiments and major engineering tests were performed, whichwere mostly focused on astrobiology, robotics, human factors, geoscience and spacesuit operations. Major assets of OeWF include two advanced spacesuit simulators Aouda [11], an increasingly evolving Mission Support Center, a dedicated Remote Science Support team [12], and a growing set of Standard Operating Procedures defining major workflows within a mission team. The spacesuit simulators were operated by a total of 18 analog astronauts, who were selected and trained during a >6 month program. Total EVA time is nearly 600 hours, leading to a significant experience in analog field simulations. AMADEE-15: The mission took place between August 2nd and 14th 2015 at the Kaunertal Glacier in Tyrol, Austria. This glacier was selected as a study site because of its accessibility and high number of micro-landscapes analogous to those expected on Mars in locations where abundant water ice is present. As such it is considered a first-tier Mars analog [13]. The Base station was located at N 46.86320, E 10.71401 at 2800 masl, the highest reached location was on elevation of 2887 m. Eleven

  7. Intratracheal heparin improves plastic bronchitis due to sulfur mustard analog.

    Science.gov (United States)

    Houin, Paul R; Veress, Livia A; Rancourt, Raymond C; Hendry-Hofer, Tara B; Loader, Joan E; Rioux, Jacqueline S; Garlick, Rhonda B; White, Carl W

    2015-02-01

    Inhalation of sulfur mustard (SM) and SM analog, 2-chloroethyl ethyl sulfide (CEES), cause fibrinous cast formation that occludes the conducting airways, similar to children with Fontan physiology-induced plastic bronchitis. These airway casts cause significant mortality and morbidity, including hypoxemia and respiratory distress. Our hypothesis was that intratracheal heparin, a highly cost effective and easily preserved rescue therapy, could reverse morbidity and mortality induced by bronchial cast formation. Sprague-Dawley rats were exposed to 7.5% CEES via nose-only aerosol inhalation to produce extensive cast formation and mortality. The rats were distributed into three groups: non-treated, phosphate-buffered saline (PBS)-treated, and heparin-treated groups. Morbidity was assessed with oxygen saturations and clinical distress. Blood and bronchoalveolar lavage fluid (BALF) were obtained for analysis, and lungs were fixed for airway microdissection to quantify the extent of airway cast formation. Heparin, given intratracheally, improved survival (100%) when compared to non-treated (75%) and PBS-treated (90%) controls. Heparin-treated rats also had improved oxygen saturations, clinical distress and airway cast scores. Heparin-treated rats had increased thrombin clotting times, factor Xa inhibition and activated partial thromboplastin times, indicating systemic absorption of heparin. There were also increased red blood cells (RBCs) in the BALF in 2/6 heparin-treated rats compared to PBS-treated control rats. Intratracheal heparin 1 hr after CEES inhalation improved survival, oxygenation, airway obstruction, and clinical distress. There was systemic absorption of heparin in rats treated intratracheally. Some rats had increased RBCs in BALF, suggesting a potential for intrapulmonary bleeding if used chronically after SM inhalation. © 2014 Wiley Periodicals, Inc.

  8. Transmission line analogy for relativistic Poynting-flux jets

    Science.gov (United States)

    Lovelace, R. V. E.; Kronberg, P. P.

    2013-04-01

    Radio emission, polarization and Faraday rotation maps of the radio jet of the galaxy 3C 303 have shown that one knot of this jet carries a galactic-scale electric current and that it is magnetically dominated. We develop the theory of magnetically dominated or Poynting-flux jets by making an analogy of a Poynting jet with a transmission line or waveguide carrying a net current and having a potential drop across it (from the jet's axis to its radius) and a definite impedance which we derive. The electromagnetic energy flow in the jet is the jet impedance times the square of the jet current. The observed current in 3C 303 can be used to calculate the electromagnetic energy flow in this magnetically dominated jet. Time dependent but not necessarily small perturbations of a Poynting-flux jet are described by the `telegrapher's equations'. These predict the propagation speed of disturbances and the effective wave impedance for forward and backward propagating wave components. A localized disturbance of a Poynting jet gives rise to localized dissipation in the jet which may explain the enhanced synchrotron radiation in the knots of the 3C 303 jet, and also in the apparently stationary knot HST-1 in the jet near the nucleus of the nearby galaxy M87. For a relativistic Poynting jet on parsec scales, the reflected voltage wave from an inductive termination or load can lead to a backward propagating wave which breaks down the magnetic insulation of the jet giving |{boldsymbol E}| /|{boldsymbol B}|ge 1. At the threshold for breakdown, |{boldsymbol E}|/|{boldsymbol B}|=1, positive and negative particles are directly accelerated in the {boldsymbol E} × {boldsymbol B} direction which is approximately along the jet axis. Acceleration can occur up to Lorentz factors ˜107. This particle acceleration mechanism is distinct from that in shock waves and that in magnetic field reconnection.

  9. C-Type Natriuretic Peptide Analog as Therapy for Achondroplasia.

    Science.gov (United States)

    Legeai-Mallet, Laurence

    2016-01-01

    Fibroblast growth factor receptor 3 (FGFR3) is an important regulator of bone formation. Gain-of-function mutations in the FGFR3 gene result in chondrodysplasias which include achondroplasia (ACH), the most common form of dwarfism, in which skull, appendicular and axial skeletons are affected. The skeletal phenotype of patients with ACH showed defective proliferation and differentiation of the chondrocytes in the growth plate cartilage. Both endochondral and membranous ossification processes are disrupted during development. At cellular level, Fgfr3 mutations induce increased phosphorylation of the tyrosine kinase receptor FGFR3, which correlate with an enhanced activation of its downstream signaling pathways. Potential therapeutic strategies have emerged for ACH. Several preclinical studies have been conducted such as the C-type natriuretic peptide (CNP) analog (BMN111), intermittent parathyroid hormone injections, soluble FGFR3 therapy, and meclozine and statin treatments. Among the putative targets to antagonize FGFR3 signaling, CNP (or BMN111) is one of the most promising strategies. BMN111 acts as a key regulator of longitudinal bone growth by downregulating the mitogen-activated protein kinase pathway, which is activated as a result of a FGFR3 gain-of-function mutation. Preclinical studies showed that BMN111 treatment led to a large improvement in skeletal parameters in Fgfr3Y367C/+ mice mimicking ACH. In 2014, a clinical trial (phase 2) of BMN111 in pediatric patients with ACH has started. This first clinical trial marks the first big step towards real treatment for these patients. © 2016 S. Karger AG, Basel.

  10. Impact of device engineering on analog/RF performances of tunnel field effect transistors

    Science.gov (United States)

    Vijayvargiya, V.; Reniwal, B. S.; Singh, P.; Vishvakarma, S. K.

    2017-06-01

    The tunnel field effect transistor (TFET) and its analog/RF performance is being aggressively studied at device architecture level for low power SoC design. Therefore, in this paper we have investigated the influence of the gate-drain underlap (UL) and different dielectric materials for the spacer and gate oxide on DG-TFET (double gate TFET) and its analog/RF performance for low power applications. Here, it is found that the drive current behavior in DG-TFET with a UL feature while implementing dielectric material for the spacer is different in comparison to that of DG-FET. Further, hetero gate dielectric-based DG-TFET (HGDG-TFET) is more resistive against drain-induced barrier lowering (DIBL) as compared to DG-TFET with high-k (HK) gate dielectric. Along with that, as compared to DG-FET, this paper also analyses the attributes of UL and dielectric material on analog/RF performance of DG-TFET in terms of transconductance (gm ), transconductance generation factor (TGF), capacitance, intrinsic resistance (Rdcr), cut-off frequency (F T), and maximum oscillation frequency (F max). The LK spacer-based HGDG-TFET with a gate-drain UL has the potential to improve the RF performance of device.

  11. Analog of parental empathy: association with physical child abuse risk and punishment intentions.

    Science.gov (United States)

    Rodriguez, Christina M

    2013-08-01

    Current research has been inconsistent in corroborating that parents' compromised empathy is associated with elevated physical child abuse risk, perhaps in part because of an emphasis on dispositional empathy rather than empathy directed at their own children. Research has also relied on self-reports of empathy that are susceptible to participant misrepresentation. The present study utilized an analog task of parental empathy to investigate the association of parental empathy toward one's own child with physical child abuse potential and with their tendency to punish perceived child misbehavior. A sample of 135 mothers and their 4-9 year old children were recruited, with mothers estimating their children's emotional reactions using a behavioral simulation of parental empathy. Mothers also provided self-reports on two measures of child abuse potential, a measure of negative attributions and expected punishment of children using vignettes, as well as a traditional measure of dispositional empathic concern and perspective-taking. Findings suggest that parental demonstration of poorer empathic ability on the analog task was significantly related to increased physical abuse potential, likelihood to punish, and negative child attributions. However, self-reported dispositional empathy exhibited the pattern of inconsistent associations previously observed in the literature. Parental empathy appears to be a relevant target for prevention and intervention programs. Future research should also consider similar analog approaches to investigate such constructs to better uncover the factors that elevate abuse risk. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Fuzzy classifier for fault diagnosis in analog electronic circuits.

    Science.gov (United States)

    Kumar, Ashwani; Singh, A P

    2013-11-01

    Many studies have presented different approaches for the fault diagnosis with fault models having ± 50% variation in the component values in analog electronic circuits. There is still a need of the approaches which provide the fault diagnosis with the variation in the component value below ± 50%. A new single and multiple fault diagnosis technique for soft faults in analog electronic circuit using fuzzy classifier has been proposed in this paper. This technique uses the simulation before test (SBT) approach by analyzing the frequency response of the analog circuit under faulty and fault free conditions. Three signature parameters peak gain, frequency and phase associated with peak gain, of the frequency response of the analog circuit are observed and extracted such that they give unique values for faulty and fault free configuration of the circuit. The single and double fault models with the component variations from ± 10% to ± 50% are considered. The fuzzy classifier along the classification of faults gives the estimated component value under faulty and faultfree conditions. The proposed method is validated using simulated data and the real time data for a benchmark analog circuit. The comparative analysis is also presented for both the validations. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Antiplasmodial activity study of angiotensin II via Ala scan analogs.

    Science.gov (United States)

    Silva, Adriana Farias; Bastos, Erick Leite; Torres, Marcelo Der Torossian; Costa-da-Silva, André Luis; Ioshino, Rafaella Sayuri; Capurro, Margareth Lara; Alves, Flávio Lopes; Miranda, Antonio; Vieira, Renata de Freitas Fischer; Oliveira, Vani Xavier

    2014-08-01

    Angiotensin II (AII) as well as analog peptides shows antimalarial activity against Plasmodium gallinaceum and Plasmodium falciparum, but the exact mechanism of action is still unknown. This work presents the solid-phase synthesis and characterization of eight peptides corresponding to the alanine scanning series of AII plus the amide-capped derivative and the evaluation of the antiplasmodial activity of these peptides against mature P. gallinaceum sporozoites. The Ala screening data indicates that the replacement of either the Ile(5) or the His(6) residues causes minor effects on the in vitro antiplasmodial activity compared with AII, i.e. AII (88%), [Ala(6) ]-AII (79%), and [Ala(5) ]-AII (75%). Analogs [Ala(3) ]-AII, [Ala(1) ]-AII, and AII-NH2 showed antiplasmodial activity around 65%, whereas the activity of the [Ala(8) ]-AII, [Ala(7) ]-AII, [Ala(4) ]-AII, and [Ala(2) ]-AII analogs is lower than 45%. Circular dichroism data suggest that AII and the most active analogs adopt a β-fold conformation in different solutions. All AII analogs, except [Ala(4) ]-AII and [Ala(8) ]-AII, show contractile responses and interact with the AT1 receptor, [Ala(5) ]-AII and [Ala(6) ]-AII. In conclusion, this approach is helpful to understand the contribution of each amino acid residue to the bioactivity of AII, opening new perspectives toward the design of new sporozoiticidal compounds. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  14. Transistor analogs of emergent iono-neuronal dynamics

    Science.gov (United States)

    Rachmuth, Guy; Poon, Chi-Sang

    2008-01-01

    Neuromorphic analog metal-oxide-silicon (MOS) transistor circuits promise compact, low-power, and high-speed emulations of iono-neuronal dynamics orders-of-magnitude faster than digital simulation. However, their inherently limited input voltage dynamic range vs power consumption and silicon die area tradeoffs makes them highly sensitive to transistor mismatch due to fabrication inaccuracy, device noise, and other nonidealities. This limitation precludes robust analog very-large-scale-integration (aVLSI) circuits implementation of emergent iono-neuronal dynamics computations beyond simple spiking with limited ion channel dynamics. Here we present versatile neuromorphic analog building-block circuits that afford near-maximum voltage dynamic range operating within the low-power MOS transistor weak-inversion regime which is ideal for aVLSI implementation or implantable biomimetic device applications. The fabricated microchip allowed robust realization of dynamic iono-neuronal computations such as coincidence detection of presynaptic spikes or pre- and postsynaptic activities. As a critical performance benchmark, the high-speed and highly interactive iono-neuronal simulation capability on-chip enabled our prompt discovery of a minimal model of chaotic pacemaker bursting, an emergent iono-neuronal behavior of fundamental biological significance which has hitherto defied experimental testing or computational exploration via conventional digital or analog simulations. These compact and power-efficient transistor analogs of emergent iono-neuronal dynamics open new avenues for next-generation neuromorphic, neuroprosthetic, and brain-machine interface applications. PMID:19404469

  15. Astaxanthin analogs, adonixanthin and lycopene, activate Nrf2 to prevent light-induced photoreceptor degeneration.

    Science.gov (United States)

    Inoue, Yuki; Shimazawa, Masamitsu; Nagano, Ryota; Kuse, Yoshiki; Takahashi, Kei; Tsuruma, Kazuhiro; Hayashi, Masahiro; Ishibashi, Takashi; Maoka, Takashi; Hara, Hideaki

    2017-07-01

    Carotenoids, in particular astaxanthin, possess potent antioxidant capabilities. Astaxanthin also induces NF-E2-related factor 2 (Nrf2), which plays a major regulatory role in the antioxidative response. However, little is known whether the carotenoid, by-products of astaxanthin, activate Nrf2. Toward this end, we screened eight astaxanthin analogs for Nrf2 activation in murine photoreceptor cell line, 661 W, by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, we monitored cell death in 661 W cells pretreated with astaxanthin analogs or only pretreated for 6 h with astaxanthin analogs and then exposed to light. Furthermore, we quantified the reactive oxygen species (ROS) production. Cell death was quantified after light exposure by nuclear staining. Nrf2-controlled genes Ho-1, Nqo-1, and Gclm by qRT-PCR and Nrf2 in the nucleus were upregulated in 661 W cells exposed astaxanthin, adonixanthin, echinenone, and lycopene. Moreover, astaxanthin, adonixanthin, echinenone, β-carotene, adonirubin, and lycopene, but not canthaxanthin, suppressed ROS production and protected cells against light-induced damage. Moreover, pretreatment with adonixanthin or lycopene only before light exposure protected against light-induced cell damage and Nrf2 silencing canceled these effects. These findings indicate that the more potent astaxanthin analogs, adonixanthin and lycopene, protect against light-induced cell damage through not only an anti-oxidative response but also through Nrf2 activation. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  16. The Fricative Sound Source Spectrum Derived from a Vocal Tract Analog.

    Science.gov (United States)

    Zagar, Lawrence Edward

    The applications of speech synthesis for computer voice response and speech analysis present the need for highly intelligible and natural synthesized speech. In order to improve the synthesis of fricative and related sounds, the use of simple models for the source spectrum of fricative sounds is investigated. The investigation is based on the use of a vocal tract analog and experimental measurements. Measurements of the sound pressure spectra of fricative consonants are made. Simple sound pressure measurements and measurements based on the technique for measuring intensity are utilized. The fricatives studied are /f/, /th/, /s/, /sh/, and /h/. Fricative sound source spectra are determined by applying an inverse filter to the measured fricative sound pressure spectra. The inverse filtering function is derived from a vocal tract analog. The resulting fricative source spectra are fit to a truncated Fourier series. The results show that structure is evident in all the source spectra except /f/. The presence of structure was related to turbulent flows. The structure of turbulent flows is relevant since fricative sound production is induced by turbulence. The structure of turbulent flows with Reynolds number near the critical Reynolds number is dependent on the initial conditions, the boundary conditions, and on the nonlinearity of the Navier Stokes equations. These three factors are tied together by bifurcation theory which is used to explain the structure present in the fricative source spectra. Also, the possibility that the structure is a by-product of the vocal tract analog is allowed. In any case, the structure evident in the source spectra indicates the use of simple models for the source spectra of fricative sounds is in error or the vocal tract analog requires revision. The fricative source spectra determined in this study can be used in future speech synthesizers. Also, the same procedure employed in this study can be used for speech analysis of speech impaired

  17. Biological effects of insulin and its analogs on cancer cells with different insulin family receptor expression.

    Science.gov (United States)

    Sciacca, Laura; Cassarino, Maria Francesca; Genua, Marco; Vigneri, Paolo; Giovanna Pennisi, Maria; Malandrino, Pasqualino; Squatrito, Sebastiano; Pezzino, Vincenzo; Vigneri, Riccardo

    2014-11-01

    Hyperinsulinemia is a likely cause of the increased cancer incidence and mortality in diabetic patients, but its role is difficult to define in vivo. Previous in vitro studies testing the mitogenic potential of insulin and its analogs provided incomplete and sometimes contradictory results. To better evaluate cancer cell responsiveness to insulin, to its analogs and to IGF-I, we measured under identical experimental conditions cell proliferation, invasiveness, and foci formation in six cancer cell lines with different insulin receptor family expression levels. The cancer cells studied have a different expression of insulin receptor (IR), its isoforms (IR-A and IR-B), and of the IGF-I receptor. The data indicate that insulin stimulates proliferation in all cancer cell lines, invasiveness in some, and foci formation in none. Cancer cell responses to insulin (and IGF-I) are not related to receptor expression levels; moreover, hormone-stimulated proliferation and invasiveness are not correlated. IGF-I is a more potent stimulator than insulin in most but not all cancer cell lines. Insulin analogs including M1 and M2 Glargine metabolites stimulate cancer cells similar to insulin. However, exceptions occur for specific analogs in particular cancer cells. In conclusion, in vitro insulin is an effective growth factor for all cancer cells but the biological response to insulin cannot be predicted on the basis of receptor expression levels. In the clinical setting, these observations should be taken in account when deciding treatment for diabetic patients who are at risk of undiscovered cancer or survivors of oncological diseases. © 2014 Wiley Periodicals, Inc.

  18. Inhibitory Effects of Resveratrol Analogs on Mushroom Tyrosinase Activity

    Directory of Open Access Journals (Sweden)

    Nádia Rezende Barbosa Raposo

    2012-10-01

    Full Text Available Skin pigmentation disorders typically involve an overproduction or uneven distribution of melanin, which results in skin spots. Resveratrol can inhibit tyrosinase, the active enzyme in the synthesis of melanin, but it does not inhibit the synthesis of melanin to an extent that enables its use alone as a skin whitening agent in pharmaceutical formulations, so its use as a coadjuvant in treatment of hyperpigmentation is suggested. Six resveratrol analogs were tested for tyrosinase inhibitory activity in vitro. Among the analogs tested, compound D was the most powerful tyrosinase inhibitor (IC50 = 28.66 µg/mL, two times more active than resveratrol (IC50 = 57.05 µg/mL, followed by the analogs A, E, B, F and C, respectively. This demonstrated that the hydroxylation at C4' on the phenolic ring was the molecular modification with most importance for the observed activity.

  19. Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing

    Energy Technology Data Exchange (ETDEWEB)

    Gaudi, B; Bennett, D; Udalski, A; Gould, A; Christie, G; Maoz, D; Dong, S; McCormick, J; Szymanski, M; Tristram, P; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; DePoy, D; Han, C; Kaspi, S; Lee, C; Mallia, F; Natusch, T; Pogge, R; Park, B; Abe, F; Bond, I; Botzler, C; Fukui, A; Hearnshaw, J; Itow, Y; Kamiya, K; Korpela, A; Kilmartin, P; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N; Sako, T; Saito, T; Sato, S; Skuljan, L; Sullivan, D; Sumi, T; Sweatman, W; Yock, P; Albrow, M; Beaulieu, J; Burgdorf, M; Cook, K; Coutures, C; Dominik, M; Dieters, S; Fouque, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

    2007-11-08

    Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the first detection of a multiple-planet system with microlensing. We identify two planets with masses of {approx} 0.71 and {approx} 0.27 times the mass of Jupiter and orbital separations of {approx} 2.3 and {approx} 4.6 astronomical units orbiting a primary of mass {approx} 0.50 solar masses. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only 6 confirmed microlensing planet detections suggests that solar system analogs may be common.

  20. Electrothermal simulation of SOI CMOS analog integrated circuits

    Science.gov (United States)

    Yu, Feixia; Cheng, Ming-C.

    2007-05-01

    An analytical approach, combining a heat flow device model for SOI devices and a thermal model for interconnects, is presented for electrothermal simulation of SOI analog integrated circuits. The proposed approach is able to account for large temperature gradients in device, heat exchanges between devices, heat losses from the silicon islands and interconnects to the substrate through oxide, and temperature influences on electronic characteristics. Electrothermal simulations of SOI analog integrated circuits in SPICE coupled with the proposed approach are performed and compared with the isothermal model using the BSIMSOI thermal circuit. Heat flow, thermal coupling and self-heating effects in some SOI analog integrated circuits influenced by non-isothermal effects are examined. Limitations of the BSIMSOI isothermal is discussed.

  1. Potential indications for somatostatin analogs in Cushing's syndrome.

    Science.gov (United States)

    Arnaldi, G; Polenta, B; Cardinaletti, M; Boscaro, M

    2005-01-01

    In recent years, somatostatin analogs have been proposed and used in the diagnosis and therapy in Cushing's syndrome (CS). In these last few years, the potential therapeutic effects of somatostain analogs have been studied in different aspects of CS. The strong expression of somatostatin receptors (SSTR) type 5 in human corticotroph cells and the demonstrated efficacy of SOM230, a novel multi-ligand somatostatin analog, in inhibiting ACTH release in vitro suggest that this new drug may be effective in the treatment of ACTH hypersecretion. Very preliminary in vivo results suggest that SOM230 could be a promising drug in medical therapy for patients with Cushing's disease (CD). Prolonged treatment and more data will be needed in order to evaluate its long-term therapeutic efficacy.

  2. A hybrid digital-analog long pulse integrator

    Energy Technology Data Exchange (ETDEWEB)

    Strait, E.J.; Broesch, J.D.; Snider, R.T.; Walker, M.L.

    1996-05-01

    A digital-analog integrator has been developed for use with inductive magnetic sensors in long-pulse tokamaks. Continuous compensation of input offsets is accomplished by alternating analog-to-digital convertor samples from the sensor and a dummy load, while an RC network provides passive integration between samples. Typically a sampling rate of 10 kHz is used. In operational tests on the DIII-D tokamak, digital and analog integration of tokamak data show good agreement. The output drift error during a 1200 s integration interval corresponds to a few percent of the anticipated signal for poloidal field probes in International Thermonuclear Experimental Reactor (ITER), and bench tests suggest that the error can be reduced further.

  3. Analog Circuit Design Optimization Based on Evolutionary Algorithms

    Directory of Open Access Journals (Sweden)

    Mansour Barari

    2014-01-01

    Full Text Available This paper investigates an evolutionary-based designing system for automated sizing of analog integrated circuits (ICs. Two evolutionary algorithms, genetic algorithm and PSO (Parswal particle swarm optimization algorithm, are proposed to design analog ICs with practical user-defined specifications. On the basis of the combination of HSPICE and MATLAB, the system links circuit performances, evaluated through specific electrical simulation, to the optimization system in the MATLAB environment, for the selected topology. The system has been tested by typical and hard-to-design cases, such as complex analog blocks with stringent design requirements. The results show that the design specifications are closely met. Comparisons with available methods like genetic algorithms show that the proposed algorithm offers important advantages in terms of optimization quality and robustness. Moreover, the algorithm is shown to be efficient.

  4. Telomerase-inhibitory effects of sugar-modified nucleotide analogs.

    Science.gov (United States)

    Jinmei, Hiroshi; Takahashi, Hazuki; Amano, Rie; Suzuki, Kaori; Saneyoshi, Mineo; Yamaguchi, Toyofumi

    2002-01-01

    Telomerase is an endogenous reverse transcriptase that uses its internal RNA moiety as a template for the synthesis of telomere repeats, thus maintaining telomere length. To study the susceptibility of telomerase to sugar-modified nucleotide analogs, inhibition by arabinofuranosylguanine 5'-triphosphate (araGTP), 3'-azido-2',3'-dideoxyguanosine 5'-triphosphate (AZdGTP), 2',3'-dideoxy-2'-fluoroarabino-furanosylguanine 5'-triphosphate (FaraGTP), and their thymine counterparts was investigated. Among these compounds, all dGTP analogs showed potent inhibitory activity against human telomerase. Conversely, dTTP analogs showed moderate or weak inhibition. Partially purified telomerase from cherry salmon testis utilized ddGTP and AZdGTP as substrates into the 3'-terminus of DNA.

  5. Further on integrator circuit analogy for natural convection

    Energy Technology Data Exchange (ETDEWEB)

    Khane, Vaibhav [Nuclear Engineering, Missouri University of Science and Technology, 225 Fulton Hall, 300W. 13th St., Rolla, MO-65409 (United States); Usman, Shoaib, E-mail: usmans@mst.ed [Nuclear Engineering, Missouri University of Science and Technology, 225 Fulton Hall, 300W. 13th St., Rolla, MO-65409 (United States)

    2010-03-15

    This research is an extension of the previous work on the development of an integrator (RC) circuit analogy for natural convection. This analogy has been proven experimentally as well as by numerical simulations. Additional Rayleigh-Benard convection numerical simulations were performed to investigate DELTAT (temperature difference between source and sink) dependence of the thermal resistance of a natural convection system. Our results suggest that analogous to voltage dependent resistor (VDR) in electrical engineering, DELTAT dependent thermal resistance is observed in natural convection system. This DELTAT dependent thermal resistance leads to a variable time constant. Moreover, this research also suggests that for a natural convection system, in addition to the thermal capacitance a kinetic energy capacitance also exists. The relative contribution of kinetic energy capacitance depends on Rayleigh number. These results provide significant step forward towards development of a new inexpensive modeling and transient analysis tool for a natural convection system.

  6. Diverse amide analogs of sulindac for cancer treatment and prevention.

    Science.gov (United States)

    Mathew, Bini; Hobrath, Judith V; Connelly, Michele C; Kiplin Guy, R; Reynolds, Robert C

    2017-10-15

    Sulindac is a non-steroidal anti-inflammatory drug (NSAID) that has shown significant anticancer activity. Sulindac sulfide amide (1) possessing greatly reduced COX-related inhibition relative to sulindac displayed in vivo antitumor activity that was comparable to sulindac in a human colon tumor xenograft model. Inspired by these observations, a panel of diverse sulindac amide derivatives have been synthesized and their activity probed against three cancer cell lines (prostate, colon and breast). A neutral analog, compound 79 was identified with comparable potency relative to lead 1 and activity against a panel of lymphoblastic leukemia cell lines. Several new series also show good activity relative to the parent (1), including five analogs that also possess nanomolar inhibitory potencies against acute lymphoblastic leukemia cells. Several new analogs identified may serve as anticancer lead candidates for further development. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  7. Practice Utilization of Algorithms for Analog Filter Group Delay Optimization

    Directory of Open Access Journals (Sweden)

    K. Hajek

    2007-04-01

    Full Text Available This contribution deals with an application of three different algorithms which optimize a group delay of analog filters. One of them is a part of the professional circuit simulator Micro Cap 7 and the others two original algorithms are developed in the MATLAB environment. An all-pass network is used to optimize the group delay of an arbitrary analog filter. Introduced algorithms look for an optimal order and optimal coefficients of an all-pass network transfer function. Theoretical foundations are introduced and all algorithms are tested using the optimization of testing analog filter. The optimization is always run three times because the second, third and fourth-order all-pass network is used. An equalization of the original group delay is a main objective of these optimizations. All outputs of all algorithms are critically evaluated and also described.

  8. An analog simulation technique for distributed flow systems

    DEFF Research Database (Denmark)

    Jørgensen, Sten Bay; Kümmel, Mogens

    1973-01-01

    Simulation of distributed flow systems in chemical engine­ering has been applied more and more during the last decade as computer techniques have developed [l]. The applications have served the purpose of identification of process dynamics and parameter estimation as well as improving process...... and process control design. Although the conventional analog computer has been expanded with hybrid techniques and digital simulation languages have appeared, none of these has demonstrated superiority in simulating distributed flow systems in general [l]. Conventional analog techniques are expensive......, especially when flow forcing and nonlinearities are simulated. Digital methods on the other. hand are time consuming. The purpose of this application note is to describe the hardware for the analog principle proposed by {2, 3]. Using this hardware ffowforcing is readily simulated, which was not feasible...

  9. The Discourse on Printed and Electronic Books: Analogies, Oppositions, and Perspectives

    Science.gov (United States)

    Velagic, Zoran

    2014-01-01

    Introduction: The point of departure for this paper is the twofold analogy (analogy of content, analogy of medium) between printed and electronic books, the aim being to draw attention to the usual perception of their capacities and relationships, to provide a rather detailed analysis of the outcome and sustainability of such analogies and…

  10. The Teaching-with-Analogies Model: Build Conceptual Bridges with Mental Models

    Science.gov (United States)

    Glynn, Shawn

    2007-01-01

    Teachers often use analogies and are unaware of it--they are using them automatically. Whenever they begin an explanation with "It's just like...," "It's similar to...," or "Think of it this way...," they are using an analogy to explain a concept to their students. An "analogy" is a similarity between concepts. Analogies can help students build…

  11. The Efficacy of Interactive Analogical Models in the Instruction of Bond Energy Curves in Undergraduate Chemistry

    Science.gov (United States)

    Shahani, Vijay M.; Jenkinson, Jodie

    2016-01-01

    We explored analogies used for introducing students to the concept of potential energy wells. Two analogy systems were developed, a spring system and a novel system consisting of electrostatic spheres. These two, distinct analogies were housed within an interactive tool that allowed students to manipulate the analogous systems and witness changes…

  12. Acoustic analog of monolayer graphene and edge states

    Science.gov (United States)

    Zhong, Wei; Zhang, Xiangdong

    2011-09-01

    Acoustic analog of monolayer graphene has been designed by using silicone rubber spheres of honeycomb lattices embedded in water. The dispersion of the structure has been studied theoretically using the rigorous multiple-scattering method. The energy spectra with the Dirac point have been verified and zigzag edge states have been found in ribbons of the structure, which are analogous to the electronic ones in graphene nanoribbons. The guided modes along the zigzag edge excited by a point source have been numerically demonstrated. The open cavity and “Z” type edge waveguide with 60° corners have also been realized by using such edge states.

  13. Silicon analog components device design, process integration, characterization, and reliability

    CERN Document Server

    El-Kareh, Badih

    2015-01-01

    This book covers modern analog components, their characteristics, and interactions with process parameters. It serves as a comprehensive guide, addressing both the theoretical and practical aspects of modern silicon devices and the relationship between their electrical properties and processing conditions. Based on the authors’ extensive experience in the development of analog devices, this book is intended for engineers and scientists in semiconductor research, development and manufacturing. The problems at the end of each chapter and the numerous charts, figures and tables also make it appropriate for use as a text in graduate and advanced undergraduate courses in electrical engineering and materials science.

  14. Mengolah Data Video Analog menjadi Video Digital Sederhana

    Directory of Open Access Journals (Sweden)

    Nick Soedarso

    2010-10-01

    Full Text Available Nowadays, editing technology has entered the digital age. Technology will demonstrate the evidence of processing analog to digital data has become simpler since editing technology has been integrated in the society in all aspects. Understanding the technique of processing analog to digital data is important in producing a video. To utilize this technology, the introduction of equipments is fundamental to understand the features. The next phase is the capturing process that supports the preparation in editing process from scene to scene; therefore, it will become a watchable video.   

  15. The Use of Reformation to Repair Faulty Analogical Blends

    OpenAIRE

    Bundy, Alan; Maclean, Ewen

    2016-01-01

    An analogical blend is the formation of a new concept from two old ones, e.g., houseboat or boathouse from house and boat, depending on whether you align the boat with the house or its occupant. This process can be automated via the colimit algorithm from Category Theory, applied to two ontologies, plus an initial alignment between their terms. Analogical blends are often faulty, e.g. inconsistent or incomplete, so need to be repaired. Reformation is an algorithm we have developed for the dia...

  16. Developing a 300C Analog Tool for EGS

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy

    2015-03-23

    This paper covers the development of a 300°C geothermal well monitoring tool for supporting future EGS (enhanced geothermal systems) power production. This is the first of 3 tools planed. This is an analog tool designed for monitoring well pressure and temperature. There is discussion on 3 different circuit topologies and the development of the supporting surface electronics and software. There is information on testing electronic circuits and component. One of the major components is the cable used to connect the analog tool to the surface.

  17. High-speed analog-to-digital conversion

    CERN Document Server

    Demler, Michael J

    1991-01-01

    This book covers the theory and applications of high-speed analog-to-digital conversion. An analog-to-digital converter takes real-world inputs (such as visual images, temperature readings, and rates of speed) and transforms them into digital form for processing by computer. This book discusses the design and uses of such circuits, with particular emphasis on improving the speed of the conversion process and the accuracy of its output--how well the output is a corresponding digital representation of the output*b1input signal. As computers become increasingly interfaced to the outside world, ""

  18. Synthesis of I-125 labeled photoaffinity rapamycin analogs

    Energy Technology Data Exchange (ETDEWEB)

    Shu, A.Y.L.; Yamashita, D.S.; Holt, D.A.; Heys, J.R. [SmithKline Beecham Pharmaceuticals, King of Prussia, PA (United States)

    1996-03-01

    Two no-carrier-added {sup 125}I-labelled photoaffinity rapamycin analogs were prepared: 7-demethoxy-7-(4-azido-3-{sup 125}I-benzyloxy) rapamycin and its C{sub 28}-C{sub 29} seco analog. The key reactions of the synthesis were substitution of the C{sub 7} methoxyl of rapamycin with 4-azido-3-tributylstannylbenzyloxy group, exchange of tributyltin with {sup 125}I using Na{sup 125}I and Chloramine-T, and a ZnCl{sub 2} mediated retro-Aldol cleavage of the C{sub 28}-C{sub 29} bond of rapamycin. (author).

  19. Artificial intelligence methods in diagnostics of analog systems

    Directory of Open Access Journals (Sweden)

    Bilski Piotr

    2014-06-01

    Full Text Available The paper presents the state of the art and advancement of artificial intelligence methods in analog systems diagnostics. Firstly, the diagnostic domain is introduced and its problems explained. Then, computational intelligence approaches usable for fault detection and identification are reviewed. Particular groups of methods are presented in detail, explaining their usefulness and drawbacks. Examples, such as the induction motor or the electronic filter, are provided to show the applicability of the presented approaches for monitoring the state of analog objects from engineering domains. The discussion section reviews the presented approaches, their future prospects and problems to be solved.

  20. Foucault's Pendulum, Analog for an Electron Spin State

    Science.gov (United States)

    Linck, Rebecca

    2012-11-01

    The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon.

  1. Evaluation of the therapeutic potential of a CNP analog in a Fgfr3 mouse model recapitulating achondroplasia.

    Science.gov (United States)

    Lorget, Florence; Kaci, Nabil; Peng, Jeff; Benoist-Lasselin, Catherine; Mugniery, Emilie; Oppeneer, Todd; Wendt, Dan J; Bell, Sean M; Bullens, Sherry; Bunting, Stuart; Tsuruda, Laurie S; O'Neill, Charles A; Di Rocco, Federico; Munnich, Arnold; Legeai-Mallet, Laurence

    2012-12-07

    Achondroplasia (ACH), the most common form of dwarfism, is an inherited autosomal-dominant chondrodysplasia caused by a gain-of-function mutation in fibroblast-growth-factor-receptor 3 (FGFR3). C-type natriuretic peptide (CNP) antagonizes FGFR3 downstream signaling by inhibiting the pathway of mitogen-activated protein kinase (MAPK). Here, we report the pharmacological activity of a 39 amino acid CNP analog (BMN 111) with an extended plasma half-life due to its resistance to neutral-endopeptidase (NEP) digestion. In ACH human growth-plate chondrocytes, we demonstrated a decrease in the phosphorylation of extracellular-signal-regulated kinases 1 and 2, confirming that this CNP analog inhibits fibroblast-growth-factor-mediated MAPK activation. Concomitantly, we analyzed the phenotype of Fgfr3(Y367C/+) mice and showed the presence of ACH-related clinical features in this mouse model. We found that in Fgfr3(Y367C/+) mice, treatment with this CNP analog led to a significant recovery of bone growth. We observed an increase in the axial and appendicular skeleton lengths, and improvements in dwarfism-related clinical features included flattening of the skull, reduced crossbite, straightening of the tibias and femurs, and correction of the growth-plate defect. Thus, our results provide the proof of concept that BMN 111, a NEP-resistant CNP analog, might benefit individuals with ACH and hypochondroplasia. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  2. Evaluation of the Therapeutic Potential of a CNP Analog in a Fgfr3 Mouse Model Recapitulating Achondroplasia

    Science.gov (United States)

    Lorget, Florence; Kaci, Nabil; Peng, Jeff; Benoist-Lasselin, Catherine; Mugniery, Emilie; Oppeneer, Todd; Wendt, Dan J.; Bell, Sean M.; Bullens, Sherry; Bunting, Stuart; Tsuruda, Laurie S.; O'Neill, Charles A.; Di Rocco, Federico; Munnich, Arnold; Legeai-Mallet, Laurence

    2012-01-01

    Achondroplasia (ACH), the most common form of dwarfism, is an inherited autosomal-dominant chondrodysplasia caused by a gain-of-function mutation in fibroblast-growth-factor-receptor 3 (FGFR3). C-type natriuretic peptide (CNP) antagonizes FGFR3 downstream signaling by inhibiting the pathway of mitogen-activated protein kinase (MAPK). Here, we report the pharmacological activity of a 39 amino acid CNP analog (BMN 111) with an extended plasma half-life due to its resistance to neutral-endopeptidase (NEP) digestion. In ACH human growth-plate chondrocytes, we demonstrated a decrease in the phosphorylation of extracellular-signal-regulated kinases 1 and 2, confirming that this CNP analog inhibits fibroblast-growth-factor-mediated MAPK activation. Concomitantly, we analyzed the phenotype of Fgfr3Y367C/+ mice and showed the presence of ACH-related clinical features in this mouse model. We found that in Fgfr3Y367C/+ mice, treatment with this CNP analog led to a significant recovery of bone growth. We observed an increase in the axial and appendicular skeleton lengths, and improvements in dwarfism-related clinical features included flattening of the skull, reduced crossbite, straightening of the tibias and femurs, and correction of the growth-plate defect. Thus, our results provide the proof of concept that BMN 111, a NEP-resistant CNP analog, might benefit individuals with ACH and hypochondroplasia. PMID:23200862

  3. Los pasiegos. La analogía salvaje y lo salvaje de la analogía

    Directory of Open Access Journals (Sweden)

    JAIME DE LA CALLE VALVERDE

    2007-01-01

    -entendiendo salvaje como un pensamiento humano prístino-: por un lado en sus relaciones con el racionalismo (¿emerge la analogía desde el racionalismo?, ¿qué relación guarda con éste?, ¿su nacimiento es resultado de una función «natural»? y por otro sobre la naturaleza social de lo salvaje a partir de las bases sociales que lo producen. Es decir, se rastrea lo que de salvaje tiene la analogía, si la analogía es o no una función ahistórica y asocial del intelecto humano. No se examina todo el complejo analógico de los pasiegos, únicamente aquél que establece relaciones homólogas entre las vacas y el entorno.

  4. The incretin approach for diabetes treatment: modulation of islet hormone release by GLP-1 agonism

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Ørskov, Cathrine

    2004-01-01

    Glucagon-like peptide (GLP)-1 is a gut hormone that stimulates insulin secretion, gene expression, and beta-cell growth. Together with the related hormone glucose-dependent insulinotropic polypeptide (GIP), it is responsible for the incretin effect, the augmentation of insulin secretion after ora...

  5. Sulfated gastrin stimulates ghrelin and growth hormone release but inhibits insulin secretion in cattle.

    Science.gov (United States)

    Zhao, Hongqiong; Yannaing, Swe; Thanthan, Sint; Kuwayama, Hideto

    2011-11-01

    This study was designed to determine the effects of gastrin on the circulating levels of ghrelin, growth hormone (GH), insulin, glucagon and glucose in ruminants. Two experiments were done in eight Holstein steers. Animals were randomly assigned to receive intravenous bolus injections: (1) 0.1% bovine serum albumin in saline as vehicle, 0.8, 4.0 and 20.0 μg/kg body weight (BW) of bovine sulfated gastrin-34; (2) vehicle, 0.53 μg/kg BW of bovine sulfated gastrin-17 alone or combined with 20.0 μg/kg BW of [D-Lys(3)]-GHRP-6, the selective antagonist of GHS-R1a. Blood samples were collected from -10 to 150 min relative to injection time. Concentrations of acyl and total ghrelin in response to gastrin-34 injection were significantly increased in a dose-dependent manner. Concentrations of GH were also markedly elevated by gastrin-34 injection; however, the effect of 20.0 μg/kg was weaker than that of 4.0 μg/kg. The three doses of gastrin-34 equally decreased insulin levels within 15 min and maintained the level until the time of last sampling. Gastrin-34 had no effect (P > 0.05) on the levels of glucagon and glucose. Levels of acyl ghrelin increased after administration of gastrin-17 alone or combined with [D-Lys(3)]-GHRP-6; however, [D-Lys(3)]-GHRP-6 did not block the elevation of GH by gastrin-17. The present results indicate that sulfated gastrin stimulates both ghrelin and GH release, but the GHS-R1a may not contribute to the release of GH by gastrin. Moreover, sulfated gastrin seems to indirectly maintain the homeostasis of blood glucose through the down-regulation of insulin in ruminants. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Melatonin improves memory acquisition under stress independent of stress hormone release.

    Science.gov (United States)

    Rimmele, Ulrike; Spillmann, Maria; Bärtschi, Carmen; Wolf, Oliver T; Weber, Cora S; Ehlert, Ulrike; Wirtz, Petra H

    2009-03-01

    Animal studies suggest that the pineal hormone melatonin influences basal stress hormone levels and dampens hormone reactivity to stress. We investigated whether melatonin also has a suppressive effect on stress-induced catecholamine and cortisol release in humans. As stress hormones affect memory processing, we further examined a possible accompanying modulation of memory function. Fifty healthy young men received a single oral dose of either 3 mg melatonin (n = 27) or placebo medication (n = 23). One hour later, they were exposed to a standardized psychosocial laboratory stressor (Trier Social Stress Test). During stress, subjects encoded objects distributed in the test room, for which memory was assessed a day later ("memory encoding under stress"). Fifteen minutes following stress, memory retrieval for words learnt the day before was tested ("memory retrieval after stress"). Plasma epinephrine and norepinephrine levels, salivary free cortisol levels and psychological responses (attention, wakefulness) were repeatedly measured before and after stress exposure. Melatonin specifically enhanced recognition memory accuracy of objects encoded under stress (p cortisol levels were highest, retrieval of memories acquired the day before was not influenced by melatonin. Moreover, melatonin did not influence stress-induced elevation of catecholamine and cortisol levels which in turn did not correlate with the effects of melatonin on memory. The findings point to a primary action of melatonin on central nervous stimulus processing under conditions of stress and possibly on memory consolidation and exclude any substantial suppressive action of the substance on hormonal stress responses.

  7. Diverse effects of tachykinins on luteinizing hormone release in male rats: mechanism of action.

    Science.gov (United States)

    Kalra, P S; Sahu, A; Bonavera, J J; Kalra, S P

    1992-09-01

    The tachykinins are a group of structurally related peptides found in the rat hypothalamus and anterior pituitary. We have evaluated the effects of four tachykinins on LH release in male rats. In intact male rats, intracerebroventricular (icv) injection of neurokinin A (NKA), neuropeptide K (NPK), and neuropeptide-gamma (NP gamma) elicited dose-related, transient increases in plasma LH. Substance P (SP) was ineffective under these conditions. A further examination showed that in vitro incubation with either NPK or NP gamma of hemipituitaries from intact but not castrated male rats promoted release of LH into the medium, thereby revealing that the excitatory effects of tachykinins in intact male rats may, in part, be a result of stimulation of LH release directly from the anterior pituitary. On the other hand, the effects of these four tachykinins on LH release were different in castrated rats. Intracerebroventricular injection of NPK, NKA, and NP gamma as well as SP, which was ineffective in intact male rats, evoked a long-lasting suppression of LH release. Comparatively, NPK was the most effective tachykinin in eliciting LH responses in both of these tests involving different endocrine environments. We next evaluated the possibility that the inhibitory effects of tachykinins (NPK) may be mediated by activation of inhibitory endogenous opioid peptides. The results showed that iv infusion of the opiate receptor antagonist naloxone, to block the possible inhibitory effects of endogenous opioid peptides, only partially counteracted the suppressive effects of icv NPK on plasma LH levels. Thus, in addition to revealing the diverse effects of structurally related tachykinins on LH release, the results of these investigations showed specifically that the NK-2 receptor agonists NPK, NP gamma, and NKA stimulated LH release in intact rats, in part, by a direct action at the level of the pituitary, whereas the NK-1 receptor agonist SP was inactive under these conditions. These findings imply a paracrine/autocrine mode of excitatory action on LH release involving pituitary NK-2 receptor subtypes. On the other hand, in castrated rats, all four tachykinins readily suppressed LH release by a central action involving, in part, an activation of hypothalamic opioid systems.

  8. Lack of stimulation of 24-hour growth hormone release by hypocaloric diet in obesity

    DEFF Research Database (Denmark)

    Rasmussen, M H; Juul, A; Kjems, L L

    1995-01-01

    Obesity is associated with a marked reduction in the spontaneous secretion of GH. To investigate the effect of acute alterations in calorie intake on GH release, 24-hr spontaneous GH release was measured during habitual calorie intake as well as during a short term, very low calorie diet (VLCD......-I (IGF-I), IGF-binding protein-1 (IGFBP-1), IGF-binding protein-3 (IGFBP-3), insulin, pro-insulin, and blood glucose were measured during habitual energy intake as well as during the hypocaloric diet. Twenty-four-hour GH release profiles and IGFBP-1 were decreased, and insulin as well as proinsulin....... This suggests a reversible defect in GH release, rather than a persistent preexisting disorder. It is hypothesized that enhanced bioavailability of IGF-I, acting in concert with elevated proinsulin and insulin levels, may account for the lack of stimulation of 24-hr GH release by the hypocaloric diet in obese...

  9. Pulsatile luteinising hormone releasing hormone for ovulation induction in subfertility associated with polycystic ovary syndrome

    NARCIS (Netherlands)

    Bayram, N.; van Wely, M.; Vandekerckhove, P.; Lilford, R.; van der Veen, F.

    2000-01-01

    BACKGROUND: In normal menstrual cycles, gonadotrophin releasing hormone (GnRH) secretion is pulsatile, with intervals of 60-120 minutes in the follicular phase. Treatment with pulsatile GnRH infusion by the intra-venous or subcutaneous route using a portable pump has been used successfully in

  10. Pituitary adenomas in mice transgenic for growth hormone-releasing hormone

    DEFF Research Database (Denmark)

    Asa, S L; Kovacs, K; Stefaneanu, L

    1992-01-01

    It has been shown that mice transgenic for human GH-releasing hormone (GRH) develop hyperplasia of pituitary somatotrophs, lactotrophs, and mammosomatotrophs, cells capable of producing both GH and PRL, by 8 months of age. We now report that GRH transgenic mice 10-24 months of age develop pituitary...

  11. Role of Sleep and Sleep Loss in Hormonal Release and Metabolism

    OpenAIRE

    Leproult, Rachel; Van Cauter, Eve

    2009-01-01

    Compared to a few decades ago, adults, as well as children, sleep less. Sleeping as little as possible is often seen as an admirable behavior in contemporary society. However, sleep plays a major role in neuroendocrine function and glucose metabolism. Evidence that the curtailment of sleep duration may have adverse health effects has emerged in the past 10 years. Accumulating evidence from both epidemiologic studies and well-controlled laboratory studies indicates that chronic partial sleep l...

  12. Role of sleep and sleep loss in hormonal release and metabolism.

    Science.gov (United States)

    Leproult, Rachel; Van Cauter, Eve

    2010-01-01

    Compared to a few decades ago, adults, as well as children, sleep less. Sleeping as little as possible is often seen as an admirable behavior in contemporary society. However, sleep plays a major role in neuroendocrine function and glucose metabolism. Evidence that the curtailment of sleep duration may have adverse health effects has emerged in the past 10 years. Accumulating evidence from both epidemiologic studies and well-controlled laboratory studies indicates that chronic partial sleep loss may increase the risk of obesity and weight gain. The present chapter reviews epidemiologic studies in adults and children and laboratory studies in young adults indicating that sleep restriction results in metabolic and endocrine alterations, including decreased glucose tolerance, decreased insulin sensitivity, increased evening concentrations of cortisol, increased levels of ghrelin, decreased levels of leptin and increased hunger and appetite. Altogether, the evidence points to a possible role of decreased sleep duration in the current epidemic of obesity. Bedtime extension in short sleepers should be explored as a novel behavioral intervention that may prevent weight gain or facilitate weight loss. Avoiding sleep deprivation may help to prevent the development of obesity, particularly in children. Copyright 2010 S. Karger AG, Basel.

  13. Effect of the artificial sweetener, sucralose, on gastric emptying and incretin hormone release in healthy subjects.

    Science.gov (United States)

    Ma, Jing; Bellon, Max; Wishart, Judith M; Young, Richard; Blackshaw, L Ashley; Jones, Karen L; Horowitz, Michael; Rayner, Christopher K

    2009-04-01

    The incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), play an important role in glucose homeostasis in both health and diabetes. In mice, sucralose, an artificial sweetener, stimulates GLP-1 release via sweet taste receptors on enteroendocrine cells. We studied blood glucose, plasma levels of insulin, GLP-1, and GIP, and gastric emptying (by a breath test) in 7 healthy humans after intragastric infusions of 1) 50 g sucrose in water to a total volume of 500 ml (approximately 290 mosmol/l), 2) 80 mg sucralose in 500 ml normal saline (approximately 300 mosmol/l, 0.4 mM sucralose), 3) 800 mg sucralose in 500 ml normal saline (approximately 300 mosmol/l, 4 mM sucralose), and 4) 500 ml normal saline (approximately 300 mosmol/l), all labeled with 150 mg 13C-acetate. Blood glucose increased only in response to sucrose (Psucralose or saline. Gastric emptying of sucrose was slower than that of saline (t50: 87.4+/-4.1 min vs. 74.7+/-3.2 min, Psucralose 0.4 mM (73.7+/-3.1 min) or 4 mM (76.7+/-3.1 min) and saline. We conclude that sucralose, delivered by intragastric infusion, does not stimulate insulin, GLP-1, or GIP release or slow gastric emptying in healthy humans.

  14. Thyroid Hormone and Estrogen Regulate Exercise-Induced Growth Hormone Release

    Science.gov (United States)

    Ignacio, Daniele Leão; da S. Silvestre, Diego H.; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Louzada, Ruy Andrade

    2015-01-01

    Growth hormone (GH) regulates whole body metabolism, and physical exercise is the most potent stimulus to induce its secretion in humans. The mechanisms underlying GH secretion after exercise remain to be defined. The aim of this study was to elucidate the role of estrogen and pituitary type 1 deiodinase (D1) activation on exercise-induced GH secretion. Ten days after bilateral ovariectomy, animals were submitted to 20 min of treadmill exercise at 75% of maximum aerobic capacity and tissues were harvested immediately or 30 min after exercise. Non-exercised animals were used as controls. A significant increase in D1 activity occurred immediately after exercise (~60%) in sham-operated animals and GH was higher (~6-fold) 30 min after exercise. Estrogen deficient rats exhibited basal levels of GH and D1 activity comparable to those found in control rats. However, after exercise both D1 activity and serum GH levels were blunted compared to sedentary rats. To understand the potential cause-effect of D1 activation in exercise-induced GH release, we pharmacologically blocked D1 activity by propylthiouracil (PTU) injection into intact rats and submitted them to the acute exercise session. D1 inhibition blocked exercise-induced GH secretion, although basal levels were unaltered. In conclusion, estrogen deficiency impairs the induction of thyroid hormone activating enzyme D1 in the pituitary, and GH release by acute exercise. Also, acute D1 activation is essential for exercise-induced GH response. PMID:25874614

  15. Bed rest suppresses bioassayable growth hormone release in response to muscle activity

    Science.gov (United States)

    McCall, G. E.; Goulet, C.; Grindeland, R. E.; Hodgson, J. A.; Bigbee, A. J.; Edgerton, V. R.

    1997-01-01

    Hormonal responses to muscle activity were studied in eight men before (-13 or -12 and -8 or -7 days), during (2 or 3, 8 or 9, and 13 or 14 days) and after (+2 or +3 and +10 or +11 days) 17 days of bed rest. Muscle activity consisted of a series of unilateral isometric plantar flexions, including 4 maximal voluntary contractions (MVCs), 48 contractions at 30% MVC, and 12 contractions at 80% MVC, all performed at a 4:1-s work-to-rest ratio. Blood was collected before and immediately after muscle activity to measure plasma growth hormone by radioimmunoassay (IGH) and by bioassay (BGH) of tibia epiphyseal cartilage growth in hypophysectomized rats. Plasma IGH was unchanged by muscle activity before, during, or after bed rest. Before bed rest, muscle activity increased (P muscle activity, a pattern that persisted through 8 or 9 days of bed rest. However, after 13 or 14 days of bed rest, plasma concentration of BGH was significantly lower after than before muscle activity (2,594 +/- 211 to 2,085 +/- 109 microg/l). After completion of bed rest, muscle activity increased BGH by 31% at 2 or 3 days (1,807 +/- 117 to 2,379 +/- 473 microg/l; P muscle activity.

  16. Effects of suramin on hormone release by cultured rat anterior pituitary cells

    NARCIS (Netherlands)

    H.F.A.I. Marzouk (Hamdy); L.J. Hofland (Leo); F.H. den Holder (Fred); P.M. van Koetsveld (Peter); J. Steenbergen (Jacobie); J. Zuiderwijk (Joke); E.M. Abou-Hashim (Ekbal); M.H. El-Kannishy (Mohammed); F.H. de Jong (Frank); S.W.J. Lamberts (Steven)

    1990-01-01

    markdownabstractAbstract Suramin is a polyanionic compound which has been used in the treatment of trypanosomiasis and acquired immunodeficiency syndrome (AIDS), while preliminary success has been reported in the treatment of cancer. However, suramin also causes adrenal insufficiency. We have

  17. The Physiology of Growth Hormone-Releasing Hormone (GHRH) in Breast Cancer

    Science.gov (United States)

    2003-06-01

    E., Billestrup, 5813. N., Gonzalez-Manchon, C., and Vale, W. (1992). Endocrino !- 28. Jungwirtb, A., Schally, A. V., Pinski, J., H-almos, G., Groot... Endocrino !. Metab. 82,690-696. Sc!. USA 88, 8749-8753. 33. Barinaga, M., Yamamoto, G., Rivier, C., Vale, W. W., Evans, 10. Berry, S. A., Srivastava, C. H...Matsubara, S., Sato, M., Mizobuchi, M., Niimi, M., and Docherty, K. (1986). J. Endocrino !. 110, 5 1-57. Takahara, J. (1997). Endocrinology 136, 4147-4150

  18. Diacylglycerol acyltransferase-1 (DGAT1 inhibition perturbs postprandial gut hormone release.

    Directory of Open Access Journals (Sweden)

    Hua V Lin

    Full Text Available Diacylglycerol acyltransferase-1 (DGAT1 is a potential therapeutic target for treatment of obesity and related metabolic diseases. However, the degree of DGAT1 inhibition required for metabolic benefits is unclear. Here we show that partial DGAT1 deficiency in mice suppressed postprandial triglyceridemia, led to elevations in glucagon-like peptide-1 (GLP-1 and peptide YY (PYY only following meals with very high lipid content, and did not protect from diet-induced obesity. Maximal DGAT1 inhibition led to enhanced GLP-1 and PYY secretion following meals with physiologically relevant lipid content. Finally, combination of DGAT1 inhibition with dipeptidyl-peptidase-4 (DPP-4 inhibition led to further enhancements in active GLP-1 in mice and dogs. The current study suggests that targeting DGAT1 to enhance postprandial gut hormone secretion requires maximal inhibition, and suggests combination with DPP-4i as a potential strategy to develop DGAT1 inhibitors for treatment of metabolic diseases.

  19. Historians and miracles: The principle of analogy and antecedent ...

    African Journals Online (AJOL)

    I present a positive case for the historian's right to adjudicate on miracle claims and address two major objections to this conclusion: the principle of analogy and antecedent probability. At times I use the resurrection of Jesus as an example. This is the first of two articles. In the second, I will address three additional common ...

  20. Time-interleaved Analog-to-Digital Converters

    NARCIS (Netherlands)

    Louwsma, S.M.

    2009-01-01

    This thesis describes the feasibility of an analog-to-digital converter (ADC) with a sample-rate of 1-2 GS/s, a resolution of 8-10 bits, and a state-of-the-art power efficiency of less than 1 pJ/conversion step. The time-interleaved architecture exploits parallelism to increase the sample-rate while

  1. Analogies between continuum dislocation theory, continuum mechanics and fluid mechanics

    Science.gov (United States)

    Silbermann, C. B.; Ihlemann, J.

    2017-03-01

    Continuum Dislocation Theory (CDT) relates gradients of plastic deformation in crystals with the presence of geometrically necessary dislocations. Interestingly, CDT shows striking analogies to other branches of continuum mechanics. The present contribution demonstrates this on two essential kinematical quantities which reflect tensorial dislocation properties: the (resultant) Burgers vector and the dislocation density tensor. First, the limiting process for the (resultant) Burgers vector from an integral to a local quantity is performed analogously to the limiting process from the force vector to the traction vector. By evaluating the balance of forces on a tetrahedral volume element, Cauchy found his famous formula relating traction vector and stress tensor. It is shown how this procedure may be adopted to a continuously dislocated tetrahedron. Here, the conservation of Burger’s vector implicates the introduction of the dislocation density tensor. Second, analogies between the plastic flow of a continuously dislocated solid and the liquid flow of a fluid are highlighted: the resultant Burgers vector of a dislocation ensemble plays a similar role as the (resultant) circulation of a vortex tube. Moreover, both vortices within flowing fluids and dislocations within deforming solids induce discontinuities in the velocity field and the plastic distortion field, respectively. Beyond the analogies, some peculiar properties of the dislocation density tensor are presented as well.

  2. Using an analogy in the introduction of a portfolio

    NARCIS (Netherlands)

    van Tartwijk, Jan; van Rijswijk, Martine; Tuithof, Hanneke; Driessen, Erik W.

    2008-01-01

    Students in many teacher education programmes experience confusion about portfolios. This study investigated whether using an analogy in the introduction of a portfolio helps teacher education students understand both the purpose of a portfolio and how to compile it. It was also investigated whether

  3. Digitally assisted analog beamforming for millimeter-wave communication

    NARCIS (Netherlands)

    Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

    2015-01-01

    The paper addresses the research question on how digital beamsteering algorithms can be combined with analog beamforming in the context of millimeter-wave communication for next generation (5G) cellular systems. Key is the use of coarse quantisation of the individual antenna signals next to the

  4. Quantum Analogs of Tensor Product Representations of su(1; 1)*

    NARCIS (Netherlands)

    Groenevelt, W.

    2011-01-01

    Abstract. We study representations of Uq(su(1; 1)) that can be considered as quantum analogs of tensor products of irreducible -representations of the Lie algebra su(1; 1). We determine the decomposition of these representations into irreducible -representations of Uq(su(1; 1)) by diagonalizing the

  5. Configurable analog-digital conversion using the neural engineering framework.

    Science.gov (United States)

    Mayr, Christian G; Partzsch, Johannes; Noack, Marko; Schüffny, Rene

    2014-01-01

    Efficient Analog-Digital Converters (ADC) are one of the mainstays of mixed-signal integrated circuit design. Besides the conventional ADCs used in mainstream ICs, there have been various attempts in the past to utilize neuromorphic networks to accomplish an efficient crossing between analog and digital domains, i.e., to build neurally inspired ADCs. Generally, these have suffered from the same problems as conventional ADCs, that is they require high-precision, handcrafted analog circuits and are thus not technology portable. In this paper, we present an ADC based on the Neural Engineering Framework (NEF). It carries out a large fraction of the overall ADC process in the digital domain, i.e., it is easily portable across technologies. The analog-digital conversion takes full advantage of the high degree of parallelism inherent in neuromorphic networks, making for a very scalable ADC. In addition, it has a number of features not commonly found in conventional ADCs, such as a runtime reconfigurability of the ADC sampling rate, resolution and transfer characteristic.

  6. Application of natural analog studies to exploration for ore deposits

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson, D.L. [Consulting Economic Geologist, Reno, NV (United States)

    1995-09-01

    Natural analogs are viewed as similarities in nature and are routinely utilized by exploration geologists in their search for economic mineral deposits. Ore deposit modeling is undertaken by geologists to direct their exploration activities toward favorable geologic environments and, therefore, successful programs. Two types of modeling are presented: (i) empirical model development based on the study of known ore deposit characteristics, and (ii) concept model development based on theoretical considerations and field observations that suggest a new deposit type, not known to exist in nature, may exist and justifies an exploration program. Key elements that are important in empirical model development are described, and examples of successful applications of these natural analogs to exploration are presented. A classical example of successful concept model development, the discovery of the McLaughlin gold mine in California, is presented. The utilization of natural analogs is an important facet of mineral exploration. Natural analogs guide explorationists in their search for new discoveries, increase the probability of success, and may decrease overall exploration expenditure.

  7. Natural analogs for far-field environment/hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Hoxie, D.T. [Geological Survey, Denver, CO (United States)

    1995-09-01

    This paper discusses the applicability of natural-analog studies to characterize far-field conditions in the vicinity of geologic repository systems for the disposal of high-level radioactive wastes. Conditions in the far field are determined by the natural state and evolution of the repository geosphere and its environment.

  8. High quality digital holographic reconstruction on analog film

    Science.gov (United States)

    Nelsen, B.; Hartmann, P.

    2017-05-01

    High quality real-time digital holographic reconstruction, i.e. at 30 Hz frame rates, has been at the forefront of research and has been hailed as the holy grail of display systems. While these efforts have produced a fascinating array of computer algorithms and technology, many applications of reconstructing high quality digital holograms do not require such high frame rates. In fact, applications such as 3D holographic lithography even require a stationary mask. Typical devices used for digital hologram reconstruction are based on spatial-light-modulator technology and this technology is great for reconstructing arbitrary holograms on the fly; however, it lacks the high spatial resolution achievable by its analog counterpart, holographic film. Analog holographic film is therefore the method of choice for reconstructing highquality static holograms. The challenge lies in taking a static, high-quality digitally calculated hologram and effectively writing it to holographic film. We have developed a theoretical system based on a tunable phase plate, an intensity adjustable high-coherence laser and a slip-stick based piezo rotation stage to effectively produce a digitally calculated hologram on analog film. The configuration reproduces the individual components, both the amplitude and phase, of the hologram in the Fourier domain. These Fourier components are then individually written on the holographic film after interfering with a reference beam. The system is analogous to writing angularly multiplexed plane waves with individual component phase control.

  9. Difference in brain activations during appreciating paintings and photographic analogs

    Science.gov (United States)

    Mizokami, Yoshinori; Terao, Takeshi; Hatano, Koji; Hoaki, Nobuhiko; Kohno, Kentaro; Araki, Yasuo; Kodama, Kensuke; Makino, Mayu; Izumi, Toshihiko; Shimomura, Tsuyoshi; Fujiki, Minoru; Kochiyama, Takanori

    2014-01-01

    Several studies have investigated neural correlates of aesthetic appreciation for paintings but to date the findings have been heterogeneous. This heterogeneity may be attributed to previous studies’ measurement of aesthetic appreciation of not only the beauty of paintings but also the beauty of motifs of the paintings. In order to better elucidate the beauty of paintings, it seems necessary to compare aesthetic appreciation of paintings and photographic analogs which included corresponding real images. We prepared for famous painters’ pictures and their photographic analogs which were set up to resemble each painting in order to investigate the hypothesis that there exist specific neural correlates associated with the aesthetic appreciation for paintings. Forty-four subjects participated in functional magnetic resonance study which required comparisons of aesthetic appreciation of paintings of still life and landscape versus photographic analogs including corresponding real images of still life and landscape. Bilateral cuneus and the left lingual gyrus were activated in the comparison of aesthetic appreciation of paintings versus photographic analogs. In conclusion, the present findings suggest a possibility of the existence of specific neural correlates associated with the aesthetic appreciation for paintings and that bilateral cuneus and the left lingual gyrus may be involved. PMID:25071508

  10. Baboons, like humans, solve analogy by categorical abstraction of relations.

    Science.gov (United States)

    Flemming, Timothy M; Thompson, Roger K R; Fagot, Joël

    2013-05-01

    Reasoning by analogy is one of the most complex and highly adaptive cognitive processes in abstract thinking. For humans, analogical reasoning entails the judgment and conceptual mapping of relations-between-relations and is facilitated by language (Gentner in Cogn Sci 7:155-170, 1983; Premack in Thought without language, Oxford University Press, New York, 1986). Recent evidence, however, shows that monkeys like "language-trained" apes exhibit similar capacity to match relations-between-relations (Fagot and Thompson in Psychol Sci 22:1304-1309, 2011; Flemming et al. in J Exp Psychol: Anim Behav Process 37:353-360, 2011; Truppa et al. in Plos One 6(8):e23809, 2011). Whether this behavior is driven by the abstraction of categorical relations or alternatively by direct perception of variability (entropy) is crucial to the debate as to whether nonhuman animals are capable of analogical reasoning. In the current study, we presented baboons (Papio papio) and humans (Homo sapiens) with a computerized same/different relational-matching task that in principle could be solved by either strategy. Both baboons and humans produced markedly similar patterns of responding. Both species responded different when the perceptual variability of a stimulus array fell exactly between or even closer to that of a same display. Overall, these results demonstrate that categorical abstraction trumped perceptual properties and, like humans, Old World monkeys can solve the analogical matching task by judging the categorical abstract equivalence of same/different relations-between-relations.

  11. Analogy between gambling and measurement-based work extraction

    Science.gov (United States)

    Vinkler, Dror A.; Permuter, Haim H.; Merhav, Neri

    2016-04-01

    In information theory, one area of interest is gambling, where mutual information characterizes the maximal gain in wealth growth rate due to knowledge of side information; the betting strategy that achieves this maximum is named the Kelly strategy. In the field of physics, it was recently shown that mutual information can characterize the maximal amount of work that can be extracted from a single heat bath using measurement-based control protocols, i.e. using ‘information engines’. However, to the best of our knowledge, no relation between gambling and information engines has been presented before. In this paper, we briefly review the two concepts and then demonstrate an analogy between gambling, where bits are converted into wealth, and information engines, where bits representing measurements are converted into energy. From this analogy follows an extension of gambling to the continuous-valued case, which is shown to be useful for investments in currency exchange rates or in the stock market using options. Moreover, the analogy enables us to use well-known methods and results from one field to solve problems in the other. We present three such cases: maximum work extraction when the probability distributions governing the system and measurements are unknown, work extraction when some energy is lost in each cycle, e.g. due to friction, and an analysis of systems with memory. In all three cases, the analogy enables us to use known results in order to obtain new ones.

  12. Varieties of noise: analogical reasoning in synthetic biology.

    Science.gov (United States)

    Knuuttila, Tarja; Loettgers, Andrea

    2014-12-01

    The picture of synthetic biology as a kind of engineering science has largely created the public understanding of this novel field, covering both its promises and risks. In this paper, we will argue that the actual situation is more nuanced and complex. Synthetic biology is a highly interdisciplinary field of research located at the interface of physics, chemistry, biology, and computational science. All of these fields provide concepts, metaphors, mathematical tools, and models, which are typically utilized by synthetic biologists by drawing analogies between the different fields of inquiry. We will study analogical reasoning in synthetic biology through the emergence of the functional meaning of noise, which marks an important shift in how engineering concepts are employed in this field. The notion of noise serves also to highlight the differences between the two branches of synthetic biology: the basic science-oriented branch and the engineering-oriented branch, which differ from each other in the way they draw analogies to various other fields of study. Moreover, we show that fixing the mapping between a source domain and the target domain seems not to be the goal of analogical reasoning in actual scientific practice.

  13. Chemoselective PEGylation of Cysteine Analogs of Human Basic ...

    African Journals Online (AJOL)

    electrophoresis [SDS-PAGE]. Stability of. PEGylated and non-PEGylated forms of hbFGF cysteine analog was studied by incubating them in the presence of denaturing agent such as guanidine HCl at 37 °C for 24 h. The effect of such reagent was determined by fluorescence spectrophotometry (Luminescence spectrometer.

  14. A spin-4 analog of 3D massive gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Kovacevic, Marija; Rosseel, Jan; Townsend, Paul K.; Yin, Yihao

    2011-01-01

    A sixth-order, but ghost-free, gauge-invariant action is found for a fourth-rank symmetric tensor potential in a three-dimensional (3D) Minkowski spacetime. It propagates two massive modes of spin 4 that are interchanged by parity and is thus a spin-4 analog of linearized 'new massive gravity'. Also

  15. The Nitty Gritty: How We Make Analogs Work

    Science.gov (United States)

    Self, A. L.; Huppman, S. R.; Spence, L. A.

    2017-01-01

    NASA's Human Research Program (HRP) is becoming increasingly reliant on Isolated, Confined and Controlled (ICC) analogs to accomplish many of its research objectives. Compared to other research platforms, ICC analogs present a unique set of operational challenges that must be addressed in order to ensure a high fidelity research environment. In particular, the Human Exploration Research Analog (HERA) habitat, which is classified as an ICC environment, has been developed over the past three years to accommodate the operational needs of research investigations from each of the HRP Elements. During the development period, various types of requirements have contributed to the current operational model, which strives to achieve the highest possible level of mission fidelity with limited resources. This presentation will focus on the operational aspects of the HERA habitat, with emphasis on how we develop the analog research environment to meet researchers' needs. Specific discussion topics include mission scenario development, operational tasks, mission timeline integration, stressor implementation, console support, and improvements based on lessons learned. The information is intended to help investigators better understand the details behind HERA operations and the benefits to their research goals.

  16. A Total Dose Characterization of Five Commercial Analog Multiplexers.

    Science.gov (United States)

    1984-07-01

    Laboratory, Kirtland Air Force Base, New Mexico , under Job Order 88091145. First Lieutenant Mark R. Ackermann (NTCT) was the Laboratory Project Officer-in...b) the channel resistance R for an n-channel MOS rET. * 25 AFWL-TR-84-07 Vino +5 OTL Figure 8. A CMOS analog transfer gate. VT,, 0 DOSE Figure 9

  17. Vitamin D analogs for the treatment of secondary hyperparathyroidism.

    Science.gov (United States)

    Slatopolsky, Eduardo; Brown, Alex J

    2002-01-01

    Calcitriol controls parathyroid gland (PTG) growth and suppresses the synthesis and secretion of PTH. However, because of its potent effects on intestinal calcium and phosphorus absorption and bone mobilization, calcitriol treatment can induce hypercalcemia and hyperphosphatemia often precluding its use at therapeutic doses. In the past decade, several vitamin D analogs have been developed. These analogs retain the action on the PTG while having less effect on calcium and phosphorus. Most of these analogs for the treatment of secondary hyperparathyroidism (SH) have a modification on the side chain of calcitriol. In the USA, two vitamin D analogs 19-nor 1,25(OH)(2)D(2) and 1 alpha(OH)D(2) are currently used for the treatment of SH. Studies in animals demonstrated that 19-nor-1,25(OH)(2)D(2) is less calcemic and phosphatemic than 1 alpha(OH)D(2). The lower Ca x P product in 19-nor-1,25(OH)(2)D(2)-treated rats may be an important consideration in patient therapy. Further studies in patients are necessary to define these differences. Copyright 2002 S. Karger AG, Basel

  18. Mountain range specific analog weather forecast model for ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 117; Issue 5. Mountain range specific ... Mountain range specific analog weather forecast model is developed utilizing surface weather observations of reference stations in each mountain range in northwest Himalaya (NW-Himalaya).The model searches past ...

  19. A CMOS four-quadrant analog current multiplier

    NARCIS (Netherlands)

    Wiegerink, Remco J.

    1991-01-01

    A CMOS four-quadrant analog current multiplier is described. The circuit is based on the square-law characteristic of an MOS transistor and is insensitive to temperature and process variations. The circuit is insensitive to the body effect so it is not necessary to place transistors in individual

  20. Inherently analog quantity representations in olive baboons (Papio anubis

    Directory of Open Access Journals (Sweden)

    Allison M Barnard

    2013-05-01

    Full Text Available Strong evidence indicates that non-human primates possess a numerical representation system, but the inherent nature of that system is still debated. Two cognitive mechanisms have been proposed to account for non-human primate numerical performance: (1 a discrete object-file system limited to quantities <4, and (2 an analog system which represents quantities comparatively but is limited by the ratio between two quantities. To test the underlying nature of non-human primate quantification, we asked eight experiment -naive olive baboons (Papio anubis to discriminate between number pairs containing small (<4, large (>4, or span (small vs. large numbers of food items presented simultaneously or sequentially. The prediction from the object-file hypothesis is that baboons will only accurately choose the larger quantity in small pairs, but not large or span pairs. Conversely, the analog system predicts that baboons will be successful with all numbers, and that success will be dependent on numerical ratio. We found that baboons successfully discriminated all pair types at above chance levels. In addition, performance significantly correlated with the ratio between the numerical values. Although performance was better for simultaneous trials than sequential trials, evidence favoring analog numerical representation emerged from both conditions, and was present even in the first exposure to number pairs. Together, these data favor the interpretation that a single, coherent analog representation system underlies spontaneous quantitative abilities in primates.

  1. Beyond Analog Gravity: The Case of Exceptional Dynamics

    CERN Document Server

    Novello, M

    2011-01-01

    We show that it is possible to go beyond the simple kinematical aspects of the analog models of gravity. We exhibit the form of the Lagrangian that describes the dynamics of a self-interacting field $ \\phi $ as an interaction between $ \\phi $ and its associated effective metric $ \\hat{g}^{\\mu\

  2. Present and future trends in integrated analog signal processing circuits

    Science.gov (United States)

    Nakayama, Kenji; Iwata, Atsushi; Yanagisawa, Takeshi

    1988-12-01

    An overview is presented of the recent and future trends in the design and applications of integrated analog signal processing circuits. Design techniques are reviewed for operational amplifiers, monolithic bipolar active RC circuits, switched-capacitor (SC) circuits, continuous-time MOS circuits, and analog-to-digital converters (ADCs). High-frequency filter realization, up to 100 MHz, has been attempted by bipolar active RC circuits and GaAs circuits. Improved design techniques for SC circuits are proposed. A multistage noise shaping ADC is very useful to integrate an accurate ADC. A high SNR (more than 91 dB) is obtained by the three-stage ADC, which can be applied to digital audio systems. An overview is presented of silicon compilers for SC circuits. A mixed analog/digital master slice LSI is proposed to simplify an LSI customizing process. A voice-band modem LSI has been developed, resulting in good filter responses and SNR. Finally, promising applications of integrated analog circuits are briefly reviewed.

  3. 700-MHz switched-capacitor analog waveform sampling circuit

    Science.gov (United States)

    Haller, Gunther M.; Wooley, Bruce A.

    1994-04-01

    Analog switched-capacitor memory circuits are suitable for use in a wide range of applications where analog waveforms must be captured or delayed, such as the recording of pulse echo events and pulse shapes. Analog sampling systems based on switched-capacitor techniques offer performance superior to that of flash A/D converters and charge-coupled devices with respect to cost, density, dynamic range, sampling speed, and power consumption. This paper proposes an architecture with which sampling frequencies of several hundred megahertz can be achieved using conventional CMOS technology. Issues concerning the design and implementation of an analog memory circuit based on the proposed architecture are presented. An experimental two-channel memory with 32 sampling cells in each channel has been integrated in a 2-micron CMOS technology with poly-to-poly capacitors. The measured nonlinearity of this prototype is 0.03% for a 2.5 V input range, and the memory cell gain matching is 0.01% rms. The dynamic range of the memory exceeds 12 b for a sampling frequency of 700 MHz. The power dissipation for one channel operated from a single + 5 V supply is 2 mW.

  4. Great Computational Intelligence in the Formal Sciences via Analogical Reasoning

    Science.gov (United States)

    2017-05-08

    9 6 The Analogs Used in Our Model ...Overview of the Architecture of πVivid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 17...made about Watson, the Jeopardy! -winning AI system.2 We launched the GCI research program to change the landscape , dramatically. When Phase 1 of the

  5. Metaphors & Analogies: Power Tools for Teaching Any Subject

    Science.gov (United States)

    Wormeli, Rick

    2009-01-01

    Metaphors and analogies are more than figurative language suitable only for English classes and standardized test questions. They are "power tools" that can electrify learning in every subject and at all grade levels. Metaphors show students how to make connections between the concrete and the abstract, prior knowledge and unfamiliar concepts, and…

  6. Industrial and Biological Analogies Used Creatively by Business Professionals

    Science.gov (United States)

    Kennedy, Emily B.; Miller, Derek J.; Niewiarowski, Peter H.

    2018-01-01

    The objective of this study was to test the effect of far-field industrial (i.e., man-made) versus biological analogies on creativity of business professionals from two organizations engaged in the idea generation phase of new product development. Psychological effects, as reflected in language use, were measured via computerized text analysis of…

  7. Analysis of a developed analog trilateration system of impulsive sounds

    Science.gov (United States)

    López R., Juan Manuel; Marulanda B., Jose Ignacio

    2014-05-01

    A characterization study is made from a trilateration system for impulsive sounds, in which theoretical analysis and experimental results are presented. This system uses an analog trilateration method, avoiding to implement high frequency ADC conversion elements. It also presents the optimization of the chosen array of microphones, thus allowing for a better trilateration algorithm behavior.

  8. Graphene-on-semiconductor substrates for analog electronics

    Science.gov (United States)

    Lagally, Max G.; Cavallo, Francesca; Rojas-Delgado, Richard

    2016-04-26

    Electrically conductive material structures, analog electronic devices incorporating the structures and methods for making the structures are provided. The structures include a layer of graphene on a semiconductor substrate. The graphene layer and the substrate are separated by an interfacial region that promotes transfer of charge carriers from the surface of the substrate to the graphene.

  9. Visual analog rating of mood by people with aphasia.

    Science.gov (United States)

    Haley, Katarina L; Womack, Jennifer L; Harmon, Tyson G; Williams, Sharon W

    2015-08-01

    Considerable attention has been given to the identification of depression in stroke survivors with aphasia, but there is more limited information about other mood states. Visual analog scales are often used to collect subjective information from people with aphasia. However, the validity of these methods for communicating about mood has not been established in people with moderately to severely impaired language. The dual purposes of this study were to characterize the relative endorsement of negative and positive mood states in people with chronic aphasia after stroke and to examine congruent validity for visual analog rating methods for people with a range of aphasia severity. Twenty-three left-hemisphere stroke survivors with aphasia were asked to indicate their present mood by using two published visual analog rating methods. The congruence between the methods was estimated through correlation analysis, and scores for different moods were compared. Endorsement was significantly stronger for "happy" than for mood states with negative valence. At the same time, several participants displayed pronounced negative mood compared to previously published norms for neurologically healthy adults. Results from the two rating methods were moderately and positively correlated. Positive mood is prominent in people with aphasia who are in the chronic stage of recovery after stroke, but negative moods can also be salient and individual presentations are diverse. Visual analog rating methods are valid methods for discussing mood with people with aphasia; however, design optimization should be explored.

  10. Three-channel integrating analog-to-digital converter

    Science.gov (United States)

    Stevens, G. L.

    1978-01-01

    A three-channel integrating analog-to-digital converter was added to the complex mixer system to accept the baseband, complex signals generated by the complex mixers and output binary data to the digital demodulator for further processing and recording. The converter was first used for processing multistation data in radar experiments in the spring of 1977.

  11. Wavelet-based analogous phase scintillation index for high latitudes

    Science.gov (United States)

    Ahmed, A.; Tiwari, R.; Strangeways, H. J.; Dlay, S.; Johnsen, M. G.

    2015-08-01

    The Global Positioning System (GPS) performance at high latitudes can be severely affected by the ionospheric scintillation due to the presence of small-scale time-varying electron density irregularities. In this paper, an improved analogous phase scintillation index derived using the wavelet-transform-based filtering technique is presented to represent the effects of scintillation regionally at European high latitudes. The improved analogous phase index is then compared with the original analogous phase index and the phase scintillation index for performance comparison using 1 year of data from Trondheim, Norway (63.41°N, 10.4°E). This index provides samples at a 1 min rate using raw total electron content (TEC) data at 1 Hz for the prediction of phase scintillation compared to the scintillation monitoring receivers (such as NovAtel Global Navigation Satellite Systems Ionospheric Scintillation and TEC Monitor receivers) which operate at 50 Hz rate and are thus rather computationally intensive. The estimation of phase scintillation effects using high sample rate data makes the improved analogous phase index a suitable candidate which can be used in regional geodetic dual-frequency-based GPS receivers to efficiently update the tracking loop parameters based on tracking jitter variance.

  12. An Efficient Synthesis of Enantiopure (R-heteroarylpyrimidine Analogs

    Directory of Open Access Journals (Sweden)

    Guo-Ming Zhao

    2013-09-01

    Full Text Available An efficient synthesis of enantiopure (R-heteroarylpyrimidine analogs is described here, which involves introduction of a chiral group, formation and separation of diasteroisomers and final transformation of an amide to an ester. The absolute configuration of the enantiopure HAPs is confirmed by X-ray analysis of their intermediates.

  13. The Resilience of Analog Tools in Creative Work Practices

    DEFF Research Database (Denmark)

    Borum, Nanna; Petersson, Eva; Frimodt-Møller, Søren

    2014-01-01

    This paper discusses the use of digital and analog tools, respectively, in a creative industry. The research was done within the EU-funded research project IdeaGarden, which explores digital platforms for creative collaboration. The findings in a case study of LEGO® Future Lab, one of LEGO Group’...

  14. Antiangiogenic effects of synthetic analogs of curcumin in vivo ...

    African Journals Online (AJOL)

    The active compound curcumin is isolated from the spice turmeric. Curcumin, curcuminoids and their synthetic analogs have been shown to inhibit the progression of cancer in animal models. In colon and skin carcinogenesis the genetic changes engross different genes, but curcumin is effective in preventing ...

  15. Antiangiogenic Effects of Synthetic Analogs of Curcumin in vivo

    African Journals Online (AJOL)

    Dr Femi Olaleye

    The active compound curcumin is isolated from the spice turmeric. Curcumin, curcuminoids and their synthetic analogs have been shown to inhibit the progression of cancer in animal models. In colon and skin carcinogenesis the genetic changes engross different genes, but curcumin is effective in preventing ...

  16. Design, synthesis and antimicrobial evaluation of novel carbendazim dithioate analogs

    DEFF Research Database (Denmark)

    Zahran, Magdy A H; Osman, Amany M A; Wahed, Rania A.

    2015-01-01

    -spectroscopy. All the synthesized carbendazim analogs were screened for their in vitro antimicrobial activity against different Gram-positive (Staphylococcus aureus and Micrococcus luteus), Gram-negative (Escherichia coli and Klebsiella pneumonia) bacteria, fungi (Fusarium solani and Fusarium oxysporu) and in vivo...

  17. Antimicrobial and cell-penetrating properties of penetratin analogs

    DEFF Research Database (Denmark)

    Bahnsen, Jesper Søborg; Franzyk, Henrik; Sandberg-Schaal, Anne

    2013-01-01

    Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well as octaar......Cell-penetrating peptides (CPPs) and antimicrobial peptides (AMPs) show great potential as drug delivery vectors and new antibiotic drug entities, respectively. The current study deals with the properties of a variety of peptide analogs derived from the well-known CPP penetratin as well...... as octaarginine and different Tat sequences. The effects of peptide length, guanidinium content, and sequence of non-cationic residues were assessed in mammalian and bacterial cells. The arginine (Arg) content in the penetratin analogs was found to influence eukaryotic cell uptake efficiency, antimicrobial...... was similar, the eukaryotic cellular uptake of the shuffled analogs was noticeably lower than for native penetratin. Moreover, a point substitution of Met to Leu in native penetratin had no influence on eukaryotic cellular uptake and antimicrobial effect, and only a minor effect on cytotoxicity, in contrast...

  18. Effects of mathematical game and instructional analogy as advance ...

    African Journals Online (AJOL)

    The study investigated the effects of mathematical game and instructional analogy on students' achievement in junior secondary school mathematics. A total of 246 Junior Secondary Two (JS2) Mathematics students were involved in the study. A 3×2 factorial design was adopted in the research. From the findings, it was ...

  19. Descartes highlands: Possible analogs around the Orientale Basin, part D

    Science.gov (United States)

    Carroll, A. H.

    1972-01-01

    Two possible analogs, although not entirely satisfactory, offer reasonable alternatives to the volcanic interpretation of the Descartes highlands. Reconsideration of this complex terrain, prompted by the preliminary results of the Apollo 16 mission, will lead to the revision of some theories on lunar volcanism and also to a better understanding of the landforms caused by the formation of multi-ring basins.

  20. Analog neural network-based helicopter gearbox health monitoring system.

    Science.gov (United States)

    Monsen, P T; Dzwonczyk, M; Manolakos, E S

    1995-12-01

    The development of a reliable helicopter gearbox health monitoring system (HMS) has been the subject of considerable research over the past 15 years. The deployment of such a system could lead to a significant saving in lives and vehicles as well as dramatically reduce the cost of helicopter maintenance. Recent research results indicate that a neural network-based system could provide a viable solution to the problem. This paper presents two neural network-based realizations of an HMS system. A hybrid (digital/analog) neural system is proposed as an extremely accurate off-line monitoring tool used to reduce helicopter gearbox maintenance costs. In addition, an all analog neural network is proposed as a real-time helicopter gearbox fault monitor that can exploit the ability of an analog neural network to directly compute the discrete Fourier transform (DFT) as a sum of weighted samples. Hardware performance results are obtained using the Integrated Neural Computing Architecture (INCA/1) analog neural network platform that was designed and developed at The Charles Stark Draper Laboratory. The results indicate that it is possible to achieve a 100% fault detection rate with 0% false alarm rate by performing a DFT directly on the first layer of INCA/1 followed by a small-size two-layer feed-forward neural network and a simple post-processing majority voting stage.