204 research outputs found
Dynamics of immersed molecules in superfluids
The dynamics of a molecule immersed in a superfluid medium are considered.
Results are derived using a classical hydrodynamic approach followed by
canonical quantization. The classical model, a rigid body immersed in
incompressible fluid, permits a thorough analysis; its effective Hamiltonian
generalizes the usual rigid-rotor Hamiltonian. In contrast to the free rigid
rotor, the immersed body is shown to have chaotic dynamics. Quantization of the
classical model leads to new and experimentally verifiable features. It is
shown, for instance, that chiral molecules can behave as "quantum propellers":
the rotational-translational coupling induced by the superfluid leads to a
nonzero linear momentum in the ground state. Hydrogen peroxide is a strong
candidate for experimental detection of this effect. The signature is a
characteristic splitting of rotational absorption lines. The 1_{01} --> 1_{10}
line in hydrogen peroxide, for example, is predicted to split into three lines
separated by as much as 0.01 cm^{-1}, which is about the experimental
linewidth.Comment: 10 pages, 3 figure
Laboratory millimeter and submillimeter spectrum of HOC^+
The J = 1→2, 2→3, and 3→4 rotational transitions of the molecular ion HOC^+ have been measured in the laboratory at frequencies from 178 to 358 GHz. The data should permit astronomers to confirm the recent possible sighting of the J = 1→0 transition of HOC^+ in Sgr B2 at 89.5 GHz
Privately Connecting Mobility to Infectious Diseases via Applied Cryptography
Human mobility is undisputedly one of the critical factors in infectious
disease dynamics. Until a few years ago, researchers had to rely on static data
to model human mobility, which was then combined with a transmission model of a
particular disease resulting in an epidemiological model. Recent works have
consistently been showing that substituting the static mobility data with
mobile phone data leads to significantly more accurate models. While prior
studies have exclusively relied on a mobile network operator's subscribers'
aggregated data, it may be preferable to contemplate aggregated mobility data
of infected individuals only. Clearly, naively linking mobile phone data with
infected individuals would massively intrude privacy. This research aims to
develop a solution that reports the aggregated mobile phone location data of
infected individuals while still maintaining compliance with privacy
expectations. To achieve privacy, we use homomorphic encryption, zero-knowledge
proof techniques, and differential privacy. Our protocol's open-source
implementation can process eight million subscribers in one and a half hours.
Additionally, we provide a legal analysis of our solution with regards to the
EU General Data Protection Regulation.Comment: Added differentlial privacy experiments and new benchmark
Untersuchung zur Rolle des klassischen Erythropoietin-Rezeptors bei der Frataxin erhöhenden Wirkung von rekombinantem humanem Erythropoietin
nicht angegebenBackground:
Friedreich's ataxia (FRDA) is a neurodegenerative disorder caused by
decreased expression of the mitochondrial protein frataxin, described to
be an iron chaperone for the assembly of iron-sulfur clusters in the
mitrochondria causing iron accumulation in mitochondria, oxidative stress
and cell damage. Recently we showed that recombinant human erythropoietin
(rhuEPO) significantly increases frataxin expression by a still unknown
mechanism. In this study we investigate the role of the classical
erythropoietin receptor (EPO-R) in the frataxin- increasing effect of
rhuEPO
Materials and Methods:
Expression of the EPO-R in human erythroleukaemic K562 cells and human
monocytes THP-1 cells was detected by western blot. In the experiments
K562-cells, THP-1-cells as well as primary lymphocytes from control and
FRDA patients were incubated with different concentrations of rhuEPO.
Frataxin expression was detected by an electrochemical luminescence assay
(ECLIA) and real-time RT-PCR for frataxin-mRNA.
Results:
Western blot analysis confirmed expression of EPO-R in K562 cells, but
complete absence of EPO-R expression in THP-1 cells. However the increase
in frataxin protein expression following treatment with rhuEPO correlated
with the concentration of rhuEPO used in both cell lines, comparable to
the effect of rhuEPO on frataxin expression in primary lymphocytes from
control and FRDA patients. RhuEPO increased frataxin expression without
increasing frataxin-mRNA.
Discussion:
We investigated if the frataxin increasing effect of rhuEPO is mediated
via the classical EPO-R. To test if EPO binding to the classical EPO-R is
an essential step to mediate EPO`s effect on frataxin-expression we used
two cell culture models: one expressing the classical EPO-R, the
erythroleukaemic K562 cells and a cell line not expressing this receptor,
human monocyte THP-1 cells.
We found that rhuEPO increased frataxin expression in both cell lines,
which indicates that the effect of rhuEPO on frataxin expression is not
limited to cells expressing the classical EPO-R. RhuEPO had no effect on
frataxin mRNA suggesting that the observed increase in frataxin protein is
attributable to a posttranslational mechanism.
Conclusion:
RhuEPO increases frataxin expression by a mechanism without involvement of
the classical EPO-R. The results of this study provide a scientific basis
to further examine the effectiveness of non-erythropoietic EPO-derivatives
which do not bind to the classical EPO-R as a possible treatment option
for FRDA patients
Millimeter and Submillimeter Spectroscopy of Molecules of Atmospheric Importance
In our proposal we laid out work in three areas of relevance to atmospheric science: millimeter and submillimeter spectroscopy, variable temperature pressure broadening, and band and intensity measurements in the FIR. Below we will briefly discuss our progress during the second year of this project. In our millimeter and submillimeter (mm/submm) spectroscopic work, one of our goals has been to work towards the unification of the rotational (primarily obtained by mm/submm techniques) and rotational-vibrational (primarily obtained by infrared techniques) data sets in the context of theoretically well founded models which take advantage of the strengths of the data from each experimental technique. From the point of view of the development of the optimal data base for atmospheric observations, this is clearly a desirable goal. During the first year of this project we did an analysis of a weighted, mixed infrared and mm/submm data set of the n = 0, 1, and 2 torsional states of the ground vibrational state of HOOH. The purpose of this work is to provide a unified understanding of the spectrum, which is applicable in both the rotational and rotational - vibrational regimes. We have succeed in doing this in the context of a single weighted fit which accounts for both data sets to their respective experimental uncertainty (-0.1 and 10 MHz, respectively). Additionally, we have now done a similar analysis on the n = 0 torsional state of v(sub 3) and begun a similar analysis on v(sub 6). For several years we have been working on the mm/submm rotational spectra of the many excited vibrational states of HNO3, again with particular emphasis on the relationships between the mm/submm and infrared spectra. During the first year of this project we were able to use mm/submm spectroscopy to fully resolve the torsional splittings in 2 v(sub 9) and v(sub 5), establish a theoretically well founded quantitative relation between them, and show that both have their physical origin in the torsional motion of the v(sub 9) mode.This result has now been incorporated in a recent reanalysis of the infrared spectrum and has resulted in improved fits - eliminating what was in retrospect a systematic error associated with this previously unknown effect
Health Problems After Travel to Developing Countries
Travelers to developing countries participated in a follow-up study of the health risks associated with short (less than three months) visits to these nations. Travelers to the Greek or Canary Islands served as a control cohort. Participants completed a questionnaire to elicit information regarding pretravel vaccinations, malaria prophylaxis, and health problems during and after their journey. Relevant infections were confirmed by the respondent's personal physician. The questionnaire was completed by 10,524 travelers; the answer rate was 73.8%. After a visit to developing countries, 15% of the travelers reported health problems, 8% consulted a doctor, and 3% were unable to work for an average of 15 days. The incidence of infection per month abroad was as follows: giardiasis, 7/1,000; amebiasis, 4/1,000; hepatitis, 4/1,000; gonorrhea, 3/1,000; and malaria, helminthiases, or syphilis, <1/1,000. There were no cases of typhoid fever or choler
Health Problems After Travel to Developing Countries
Travelers to developing countries participated in a follow-up study of the health risks associated with short (less than three months) visits to these nations. Travelers to the Greek or Canary Islands served as a control cohort. Participants completed a questionnaire to elicit information regarding pretravel vaccinations, malaria prophylaxis, and health problems during and after their journey. Relevant infections were confirmed by the respondent's personal physician. The questionnaire was completed by 10,524 travelers; the answer rate was 73.8%. After a visit to developing countries, 15% of the travelers reported health problems, 8% consulted a doctor, and 3% were unable to work for an average of 15 days. The incidence of infection per month abroad was as follows: giardiasis, 7/1,000; amebiasis, 4/1,000; hepatitis, 4/1,000; gonorrhea, 3/1,000; and malaria, helminthiases, or syphilis, <1/1,000. There were no cases of typhoid fever or choler
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