62,839 research outputs found
Structure-Activity Relationships of Novel Cyclic alpha-MSH/gamma-MSH Hybrid Analogues which Lead to Potent and Selective Ligands for the Human MC3R and Human MC5R
No full textStructure-Activity Relationships of Novel Cyclic alpha-MSH/gamma-MSH Hybrid Analogues which Lead to Potent and Selective Ligands for the Human MC3R and Human MC5R
No full textStructure-Activity Relationships of alpha-MSH Analogues at the Human Melanocortin MC3, MC4, and MC5 Receptors. Discovery of Highly Selective hMC3R, hMC4R, and hMC5R Analogues.
No full textIt has been shown by extensive studies that melanotropin bioactivities are critically dependent
on the core or central tetrapeptide sequence, His-Phe-Arg-Trp, and in R-MSH it has been
demonstrated further that a reverse-turn type conformation exists at this pharmacophore. To
probe the receptor active conformation of the pharmacophore His-Phe-Arg-Trp in ç-MSH, two
different series of ç-MSH analogues have been designed and synthesized and their biological
activities determined at hMC3R, hMC4R, and hMC5R. The 1st series consists of a cyclic scan
using different disulfides or lactam bridges. It was found that cyclization of the native ç-MSH
around the highly conserved sequence can lead to shifts in affinity and selectivity for hMC4R
instead of the hMC3R as seen in the native peptide. Furthermore, a 23-membered ring is
desirable for potency (e.g., analogues 6 and 10) whereas a 26-membered ring (analogue 1, H-Tyr-
Val-c[Cys-Gly-His-Phe-Arg-Trp-Cys]-Arg-Phe-Gly-NH2 with Gly4) is more important for selectivity.
The 2nd series is made of D-2-naphthylalanine (D-Nal(2¢)) scan of the ç-MSH sequence at
position 6 and 8 and the replacement of His5 with Pro (analogue 13). Analogue 12, H-Tyr-Val-
Nle-Gly-His-Phe-Arg-D-Nal(2¢)-Asp-Arg-Phe-Gly-NH2, is a potent and selective antagonist at
the hMC4R, and analogue 15, H-Tyr-Val-Nle-Gly-Aib-Phe-Arg-D-Nal(2¢)-Asp-Arg-Phe-Gly-NH2,
is a highly selective and potent agonist of the hMC5R. A most promising analogue is 13, H-Tyr-
Val-Nle-Gly-Pro-D-Nal(2¢)-Arg-Trp-Asp-Arg-Phe-Gly-NH2, which is a very potent agonist of the
hMC4R, and this analogue can be further evaluated for feeding behavior and the regulation of
fat stores
Multiple stimuli-responsive double perovskite structured Ca2MgWO6: x % Eu3+ (x = 1–11 mol) red-emitting luminescent systems to combat counterfeiting
No full textThe rapid escalation of counterfeiting activities in recent years has posed significant challenges across diverse fields, such as pharmaceuticals, currency, luxury goods, and electronics. In response, inorganic phosphors have emerged as promising tools to combat counterfeiting due to their inherent durability and stability. The present work focuses on the synthesis of Ca2MgWO6: x % Eu3+ (x = 1-11 mol) luminescent systems via a gel-combustion route. The structural analysis of the synthesized luminescent systems confirmed a monoclinic crystal phase with a P21/n space group. The morphological study of the luminescent system revealed a network-like structure comprising interconnected particles. Photoluminescence emission spectra show a prominent red emission peak at 616 nm, corresponding to the 5D0 -> 7F2 4f-4f electronic transition of Eu3+ ions in the host matrix. The emitted red light demonstrates a color purity and quantum efficiency of 93.1 % and 77.41 %, respectively. The anticounterfeiting security patterns were developed using the Ca2MgWO6: x % Eu3+ (x = 9 mol) luminescent system, which showcases virtually invisible under normal light. However, developed patterns exhibit vivid red luminescence when exposed to multiple stimuli i.e., ultraviolet light at 365 and 395 nm wavelength, which envisages the versatility of the systems for enhancing product authentication and protecting against fraudulent activities across multiple industries. The aforementioned results demonstrated the efficacy of Ca2MgWO6: Eu3+ luminescent systems for integration into advanced security measures
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Stable voters in an unstable party environment : continuity and change in Italian electoral behaviour
No full textM.24981-1999 Paolo Segatti, Paolo Bellucci and Marco Maraffi. 30 cm. A previous version of this paper was presented at a symposium on Political Parties : Changing Roles in Contemporary Democracies, held at the Center for Advanced Study in the Social Sciences of the Juan March Institute, Madrid, December 15-17, 1994. -- P.1. Includes bibliographical references (p. 56-59
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C.
No full textDE MAIESTATE / PRAESIDE M. JACOBO THOMASIO, MORALIS PHILOSOPH. P. P., PUBLICE DISPUTABIT JOHANNES DUNTE, R. L. AUTHOR & RESPON: AD DIEM 9. SEPTEMBR. H L. Q. C.
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C. (1)
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Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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