909 research outputs found
Pituitary Hormones and Orofacial Pain
Clinical and basic research on regulation of pituitary hormones, extra-pituitary release of these hormones, distribution of their receptors and cell signaling pathways recruited upon receptor binding suggests that pituitary hormones can regulate mechanisms of nociceptive transmission in multiple orofacial pain conditions. Moreover, many pituitary hormones either regulate glands that produce gonadal hormones (GnH) or are regulated by GnH. This implies that pituitary hormones may be involved in sex-dependent mechanisms of orofacial pain and could help explain why certain orofacial pain conditions are more prevalent in women than men. Overall, regulation of nociception by pituitary hormones is a relatively new and emerging area of pain research. The aims of this review article are to: (1) present an overview of clinical conditions leading to orofacial pain that are associated with alterations of serum pituitary hormone levels; (2) discuss proposed mechanisms of how pituitary hormones could regulate nociceptive transmission; and (3) outline how pituitary hormones could regulate nociception in a sex-specific fashion. Pituitary hormones are routinely used for hormonal replacement therapy, while both receptor antagonists and agonists are used to manage certain pathological conditions related to hormonal imbalance. Administration of these hormones may also have a place in the treatment of pain, including orofacial pain. Hence, understanding the involvement of pituitary hormones in orofacial pain, especially sex-dependent aspects of such pain, is essential to both optimize current therapies as well as provide novel and sex-specific pharmacology for a diversity of associated conditions
Co-doping effect on the microstructural and electrical properties of barium stannate materials
Proton-conducting perovskite oxides are of considerable interest to researchers as promising electrolytes for low- and intermediate solid oxide electrochemical cells. Therefore, designing new potential proton-conducting phases and improving the functional properties of known materials are of great importance from both fundamental and applied viewpoints. In the present work, BaSnO3 was selected as a reference proton-conducting system and then a co-doping strategy was employed to analyze ‘composition – structure – microstructure – transport properties’ relationships. To perform such an analysis, the properties of previously studied BaSn0.7M0.3O3–δ (M = In, Sc, Y) compounds were compared here to their co-doped derivatives, BaSn0.7In0.15Sc0.15O3–δ, BaSn0.7Y0.15Sc0.15O3–δ, and BaSn0.7In0.15Y0.15O3–δ. It is found that the type of dopant affects the materials sinterability, when more coarse-crystalline ceramics are formed with increasing the average ionic radii at the Sn-position. The introduction of Y3+-cations reduces both ionic and hole conductivities compared to single-doped with In3+ or Sc3+ barium stannate materials. However, simultaneous doping with In3+/Sc3+ cations minimizes the contribution of hole conductivity compared to that of Sc-doped barium stannate with the same acceptor dopant concentration.https://doi.org/10.15826/elmattech.2024.3.03
Di-neutron elastic transfer in the 4He(6He,6He)4He reaction
Elastic He+He data measured at 15.9, and 60.3
MeV have been analyzed within the coupled reaction channels (CRC) formalism,
with the elastic-scattering and two-neutron () transfer amplitudes
coherently included. Contributions from the direct (one-step) and sequential
(two-step) -transfers were treated explicitly based on a realistic
assumption for the -transfer form factor. The oscillatory pattern observed
in He(He,He)He angular distribution at low energies was found
to be due to an interference between the elastic scattering and -transfer
amplitudes. Our CRC analysis shows consistently that the direct -transfer
strongly dominates over the sequential transfer and thus confirms the dominance
of 2He configuration over the He one in the He wave function.
This result suggests a strong clusterization of the two valence neutrons and
allows, therefore, a reliable estimate for the \emph{di-neutron} spectroscopic
amplitude.Comment: Accepted for publication in Phys. Lett.
Charge and matter distributions and form factors of light, medium and heavy neutron-rich nuclei
Results of charge form factors calculations for several unstable neutron-rich
isotopes of light, medium and heavy nuclei (He, Li, Ni, Kr, Sn) are presented
and compared to those of stable isotopes in the same isotopic chain. For the
lighter isotopes (He and Li) the proton and neutron densities are obtained
within a microscopic large-scale shell-model, while for heavier ones Ni, Kr and
Sn the densities are calculated in deformed self-consistent mean-field Skyrme
HF+BCS method. We also compare proton densities to matter densities together
with their rms radii and diffuseness parameter values. Whenever possible
comparison of form factors, densities and rms radii with available experimental
data is also performed. Calculations of form factors are carried out both in
plane wave Born approximation (PWBA) and in distorted wave Born approximation
(DWBA). These form factors are suggested as predictions for the future
experiments on the electron-radioactive beam colliders where the effect of the
neutron halo or skin on the proton distributions in exotic nuclei is planned to
be studied and thereby the various theoretical models of exotic nuclei will be
tested.Comment: 26 pages, 11 figures, 3 tables, accepted for publication in Phys.
Rev.
Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon
We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on
Si substrates using molecular-beam epitaxy. Transmission electron microscopy
(TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows
domination of the zinc-blende phase. This is further confirmed in optics of
single NWs, studied using cw and time-resolved photoluminescence (PL). A
detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP
capping in suppressing the non-radiative surface states: significant PL
enhancement in the core-shell structures exceeding 2000 times at 10K is
observed; in uncapped NWs PL is quenched at 60K whereas single core-shell
GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis
of the PL temperature dependence in both types of NW we are able to determine
the main carrier escape mechanisms leading to the PL quench
Identification of new transitions and mass assignments of levels in Pr
The previously reported levels assigned to 151,152,153Pr have recently been
called into question regarding their mass assignment. The above questioned
level assignments are clarified by measuring g-transitions tagged with A and Z
in an in-beam experiment in addition to the measurements from 252Cf spontaneous
fission (SF) and establish new spectroscopic information from to
in the Pr isotopic chain. The isotopic chain 143-153Pr has been studied from
the spontaneous fission of 252Cf by using Gammasphere and also from the
measurement of the prompt g-rays in coincidence with isotopically-identified
fission fragments using VAMOS++ and EXOGAM at GANIL. The latter were produced
using 238U beams on a 9Be target at energies around the Coulomb barrier. The
g-g-g-g data from 252Cf (SF) and those from the GANIL in-beam A- and Z-gated
spectra were combined to unambiguously assign the various transitions and
levels in 151,152,153Pr and other isotopes. New transitions and bands in
145,147,148,149,150Pr were identified by using g-g-g and g-g-g-g coincidences
and A and Z gated g-g spectra. The transitions and levels previously assigned
to 151,153Pr have been confirmed by the (A,Z) gated spectra. The transitions
previously assigned to 152Pr are now assigned to 151Pr on the basis of the
(A,Z) gated spectra. Two new bands with 20 new transitions in 152Pr and one new
band with 7 new transitions in 153Pr are identified from the g-g-g-g
coincidence spectra and the (A,Z) gated spectrum. In addition, new g-rays are
also reported in 143-146Pr. New levels of 145,147-153Pr have been established,
reliable mass assignments of the levels in 151,152,153Pr have been reported and
new transitions have been identified in 143-146Pr showing the new avenues that
are opened by combining the two experimental approaches.Comment: Accepted in Phys. Rev.
Mycobacterium tuberculosis ClpP Proteases Are Co-transcribed but Exhibit Different Substrate Specificities
PMCID: PMC3613350This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Zinc Finger Recombinases with Adaptable DNA Sequence Specificity
Site-specific recombinases have become essential tools in genetics and molecular biology for the precise excision or integration of DNA sequences. However, their utility is currently limited to circumstances where the sites recognized by the recombinase enzyme have been introduced into the DNA being manipulated, or natural ‘pseudosites’ are already present. Many new applications would become feasible if recombinase activity could be targeted to chosen sequences in natural genomic DNA. Here we demonstrate efficient site-specific recombination at several sequences taken from a 1.9 kilobasepair locus of biotechnological interest (in the bovine β-casein gene), mediated by zinc finger recombinases (ZFRs), chimaeric enzymes with linked zinc finger (DNA recognition) and recombinase (catalytic) domains. In the "Z-sites" tested here, 22 bp casein gene sequences are flanked by 9 bp motifs recognized by zinc finger domains. Asymmetric Z-sites were recombined by the concomitant action of two ZFRs with different zinc finger DNA-binding specificities, and could be recombined with a heterologous site in the presence of a third recombinase. Our results show that engineered ZFRs may be designed to promote site-specific recombination at many natural DNA sequences
Investigation of pre-structured GaAs surfaces for subsequent site-selective InAs quantum dot growth
In this study, we investigated pre-structured (100) GaAs sample surfaces with respect to subsequent site-selective quantum dot growth. Defects occurring in the GaAs buffer layer grown after pre-structuring are attributed to insufficient cleaning of the samples prior to regrowth. Successive cleaning steps were analyzed and optimized. A UV-ozone cleaning is performed at the end of sample preparation in order to get rid of remaining organic contamination
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