57 research outputs found
Postcollision interaction effects in KLL Auger spectra following argon 1s photoionization
Postcollision interaction effects on the Auger decay of a deep core hole are
studied both experimentally and theoretically. KL2,3L2,3 decay spectra of the
Ar 1s vacancy are measured with high-energy resolution with excess photon
energies ranging from 0 to 200 eV above the ionization threshold. Interaction
of the Auger electron with the photoelectron and the ion field manifests
itself in the Auger spectra as a distortion of the energy distribution of the
Auger electron close to threshold. Moreover, recapture of the photoelectron
due to energy exchange is dominating in the low-photon-energy range above
threshold. The experimental results are compared with calculations based on
the semiclassical approach to the postcollision interaction. The energies of
the discrete levels and individual recapture cross sections are computed in
the Hartree-Fock approximation. Good agreement is found between the calculated
and experimental spectra, validating the model used
N′-[Bis(benzylsulfanyl)methylidene]-4-methoxybenzohydrazide
In the title compound, C23H22N2O2S2, the dihedral angles between the 4-methoxy-substituted phenyl ring and the other two phenyl rings are 84.4 (4) and 77.7 (1)°, respectively, while the dihedral angle between the two phenyl rings is 57.5 (2)°. The amino group is not involved in an N—H hydrogen bond. The crystal packing is established by intermolecular C—H⋯O packing interactions involving a relatively rare weak three-center hydrogen bond between the keto O atom and H atoms of the two nearby phenyl rings, which link the molecules into chains running along the a axis. Additional weak intermolecular hydrogen-bond interactions between the 4-methoxy O atom and one of the phenyl rings and provide added stability to the crystal packing
Auger resonant-Raman decay after Xe L-edge photoexcitation
We have investigated resonant Auger decay of xenon following photoexcitation
of each of the three L edges under resonant-Raman conditions, which allowed us
to characterize several higher Rydberg transitions. Relative intensities for
spectator final states reached after L1−, L2−, and L3-edge excitations are
studied in detail. Thanks to state-of-the-art experimental arrangements, our
results not only reproduce the previously calculated 3d−25d and nd(n>5) state
cross sections after L3 excitation, but also allow extracting the 3d−26d
spectator state energy position and revealing its resonant behavior, blurred
by the insufficient experimental resolution in previous data sets. The 3d−26p
and 3d−27p states reached after L1 excitation as well as the 3d−25d and 3d−26d
states reached after L2 excitation are also investigated and their relative
intensities are reported and compared to ab initio Dirac-Hartree-Fock
configuration-interaction calculations. We found the signature of electronic-
state-lifetime interference effects between several coherently excited
intermediate states, due to large lifetime broadening. Electron recapture
processes are also identified above all three photoionization thresholds
Detailed assignment of normal and resonant Auger spectra of Xe near the L edges
We present a comprehensive experimental and theoretical investigation on the LMM, LMN, and LNN normal Auger spectra of xenon, which reveal excellent agreement with theory when core-hole lifetimes of the two-hole final states are taken into account. Generally, the spectra turned out to be highly complex due to a strong overlap of the Auger transitions subsequent to 2s−11/2, 2p−11/2, and 2p−13/2 ionization. This overlap is due to the splitting of the three initial L core holes and the different final M and N core holes being on the same order of magnitude of several hundred eV. The Auger transitions are assigned in detail based on the theoretical results. Most of the MM, MN, and NN final states are described well based on jj coupling. In addition, we present a detailed assignment of the resonant LM45M45 Auger transition subsequent to the 2s→6p, 7p and 2p→5d, 6d excitations
Therapeutic and immunomodulatory activities of short-course treatment of murine visceral leishmaniasis with KALSOME™10, a new liposomal amphotericin B
Visceral leishmaniasis (VL), a potentially fatal disease, is most prevalent in the Indian subcontinent,
East Africa and South America. Since the conventional antileishmanial drugs have many limitations we evaluated a
new ergosterol rich liposomal amphotericin B formulation, KALSOME™10 for its leishmanicidal efficacy, tolerability
and immunomodulatory activity. Normal healthy mice were treated with 3.5 mg/kg single and 7.5 mg/kg single and double doses ofKALSOME™10. Liver and kidney function tests were performed fourteen days after treatment. Next, normal mice were infected with Leishmania donovani amastigotes. Two months post infection they were treated with the above
mentioned doses of KALSOME™10 and sacrificed one month after treatment for estimation of parasite burden in
the liver and spleen by Limiting Dilution Assay. Leishmanial antigen stimulated splenocyte culture supernatants were collected for cytokine detection through ELISA. Flow cytometric studies were performed on normal animals treated with KALSOME™10, Amphotericin B (AmB) and AmBiosome to compare their immunomodulatory activities.
The drug was found to induce no hepato- or nephrotoxicities at the studied doses. Moreover, at all doses,
it led to significant reduction in parasite burden in two month infected BALB/c mice, with 7.5 mg/kg double dose
resulting in almost complete clearance of parasites from both liver and spleen. Interestingly, the drug at 7.5 mg/kg
double dose could almost completely inhibit the secretion of disease promoting cytokines, IL-10 and TGFβ, and
significantly elevate the levels of IFNγ and IL-12, cytokines required for control of the disease. Mice treated with KALSOME™10 showed elevated levels of IFNγ and suppressed IL-10 secretion from both CD4+ and CD8+ subsets
of T cells, as well as from culture supernatants of splenocytes, compared to that of normal, AmB and AmBisome
treated animal Treatment of infected mice with 7.5 mg/kg double dose of KALSOME™10 was safe and effective in
clearing the parasites from the sites of infection. The drug maintains the inherent immunomodulatory activities of
AmB by effectively suppressing disease promoting cytokines IL-10 and TGFβ, thereby boosting IL-12 and IFNγ levels.
This emphasizes KALSOME™10 as a promising drug alternative for lifelong protection from VL
Evaluation of Leishmania donovani Protein Disulfide Isomerase as a Potential Immunogenic Protein/Vaccine Candidate against Visceral Leishmaniasis
In Leishmania species, Protein disulfide isomerase (PDI) - a redox chaperone, is reported to be involved in its virulence and survival. This protein has also been identified, through proteomics, as a Th1 stimulatory protein in the soluble lysate of a clinical isolate of Leishmania donovani (LdPDI). In the present study, the molecular characterization of LdPDI was carried out and the immunogenicity of recombinant LdPDI (rLdPDI) was assessed by lymphocyte proliferation assay (LTT), nitric oxide (NO) production, estimation of Th1 cytokines (IFN-γ and IL-12) as well as IL-10 in PBMCs of cured/endemic/infected Leishmania patients and cured L. donovani infected hamsters. A significantly higher proliferative response against rLdPDI as well as elevated levels of IFN-γ and IL-12 were observed. The level of IL-10 was found to be highly down regulated in response to rLdPDI. A significant increase in the level of NO production in stimulated hamster macrophages as well as IgG2 antibody and a low level of IgG1 in cured patient's serum was observed. Higher level of IgG2 antibody indicated its Th1 stimulatory potential. The efficacy of pcDNA-LdPDI construct was further evaluated for its prophylactic potential. Vaccination with this construct conferred remarkably good prophylactic efficacy (∼90%) and generated a robust cellular immune response with significant increases in the levels of iNOS transcript as well as TNF-α, IFN-γ and IL-12 cytokines. This was further supported by the high level of IgG2 antibody in vaccinated animals. The in vitro as well as in vivo results thus indicate that LdPDI may be exploited as a potential vaccine candidate against visceral Leishmaniasis (VL)
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