42 research outputs found
Reactions of noble-metal oxides in ionic liquids near room temperature
The reaction of AgO, AuO, and HgO with CuCl, CuI, AgCl, AgI, AuCl, and AuI in ionic liquids ([EMIm]Cl, [BMIm]Cl) near room temperature (20â80 °C) is evaluated and results in the new compounds (CHN)CuCl, (CHN)AgI, (CHN)AuCl, [(CHN)Hg][CuCl], [(CHN)Hg][AgCl], and [EMIm][AgICl]. Thereof, (CHN)CuCl, (CHN)AgI, (CHN)AuCl, [(CHN)Hg][CuCl], and [(CHN)Hg][AgCl] are NHC complexes (NHC: N-heterocyclic carbene) with MâC bonds (M: Cu, Ag, Au, Hg). Whereas (CHN)CuCl and (CHN)AgI crystallize as single molecules, (CHN)AuCl is dimerized via aurophilic interactions. [(CHN)Hg][CuCl] and [(CHN)Hg][AgCl] exhibit Hg atoms with two HgâC bonds. Moreover, (CHN)AgI shows intense green fluorescence at room temperature with a quantum yield of 44%, whereas all other compounds do not show any emission at room temperature. Finally, [EMIm][AgICl] is not an NHC compound but contains [AgIICl]â chains with infinite dâd interaction of the silver atoms. The title compounds are characterized by single-crystal structure analysis, infrared spectroscopy, thermogravimetry, and fluorescence spectroscopy
Excited-state quantum phase transitions in spinor Bose-Einstein condensates
Excited-state quantum phase transitions (ESQPTs) extend the notion of quantum
phase transitions beyond the ground state. They are characterized by closing
energy gaps amid the spectrum. Identifying order parameters for ESQPTs poses
however a major challenge. We introduce spinor Bose-Einstein condensates as a
versatile platform for studies of ESQPTs. Based on the mean-field dynamics, we
define a topological order parameter that distinguishes between excited-state
phases, and discuss how to interferometrically access the order parameter in
current experiments. Our work opens the way for the experimental
characterization of excited-state quantum phases in atomic many-body systems.Comment: 14 pages, 3 figure
The proteome of human brain microdialysate
BACKGROUND: Cerebral microdialysis has been established as a monitoring tool in neurocritically ill patients suffering from severe stroke. The technique allows to sample small molecules in the brain tissue for subsequent biochemical analysis. In this study, we investigated the proteomic profile of human cerebral microdialysate and if the identified proteins might be useful predictors for disease characteristics in stroke for tissue at risk in the contralateral hemisphere. We analysed cerebral protein expression in microdialysate from three stroke patients sampled from the hemisphere contralateral to the lesion. Using a proteomic approach based on two-dimensional gel electrophoresis and subsequent mass spectrometry, we created a protein map for the global protein expression pattern of human microdialyste. RESULTS: We found an average of 158 ± 24 (N = 18) protein spots in the human cerebral microdialysate and could identify 95 spots, representing 27 individual proteins. Most of these have been detected in human cerebrospinal fluid before, but 10 additional proteins mainly of cerebral intracellular origin were identified exclusively in the microdialysate. CONCLUSIONS: The 10 proteins found exclusively in human cerebral microdialysate, but not in cerebrospinal fluid, indicate the possibility to monitor the progression of the disease towards deterioration. The correlation of protein composition in the human cerebral microdialysate with the patients' clinical condition and results of cerebral imaging may be a useful approach to future applications for neurological stroke diagnosis, prognosis, and treatment
Optimal squeezing for high-precision atom interferometers
We show that squeezing is a crucial resource for interferometers based on the
spatial separation of ultra-cold interacting matter. Atomic interactions lead
to a general limitation for the precision of these atom interferometers, which
can neither be surpassed by larger atom numbers nor by conventional phase or
number squeezing. However, tailored squeezed states allow to overcome this
sensitivity bound by anticipating the major detrimental effect that arises from
the interactions. We envisage applications in future high-precision
differential matter-wave interferometers, in particular gradiometers, e.g., for
gravitational-wave detection.Comment: 10 pages, 4 figure
Quantification of exhaled propofol is not feasible during single-lung ventilation using double-lumen tubes : A multicenter prospective observational trial
Background: Volatile propofol can be measured in exhaled air and correlates to
plasma concentrations with a time delay. However, the effect of single-lung ventilation on exhaled propofol is unclear. Therefore, our goal was to evaluate exhaled propofol concentrations during single-lung compared to double-lung ventilation using
double-lumen tubes.
Methods: In a first step, we quantified adhesion of volatile propofol to the inner surface of double-lumen tubes during double- and single-lumen ventilation in vitro. In a
second step, we enrolled 30 patients scheduled for lung surgery in two study centers.
Anesthesia was provided with propofol and remifentanil. We utilized left-sided
double-lumen tubes to separately ventilate each lung. Exhaled propofol concentrations were measured at 1-min intervals and plasma for propofol analyses was sampled every 20 min. To eliminate the influence of dosing on volatile propofol
concentration, exhalation rate was normalized to plasma concentration.
Results: In-vitro ventilation of double-lumen tubes resulted in increasing propofol
concentrations at the distal end of the tube over time. In vitro clamping the bronchial
lumen led to an even more pronounced increase (Î AUC +62%) in propofol gas concentration over time. Normalized propofol exhalation during lung surgery was 31%
higher during single-lung compared to double-lung ventilation.
Conclusion: During single-lung ventilation, propofol concentration in exhaled air, in
contrast to our expectations, increased by approximately one third. However, this
observation might not be affected by change in perfusion-ventilation during singlelung ventilation but rather arises from reduced propofol absorption on the inner
surface area of the double-lumen tube. Thus, it is only possible to utilize exhaled
propofol concentration to a limited extent during single-lung ventilation.
Registration of Clinical Trial: DRKS-ID DRKS00014788 (www.drks.de)
Non-perturbative Test of the Witten-Veneziano Formula from Lattice QCD
We compute both sides of the Witten-Veneziano formula using lattice
techniques. For the one side we perform dedicated quenched simulations and use
the spectral projector method to determine the topological susceptibility in
the pure Yang-Mills theory. The other side we determine in lattice QCD with
dynamical Wilson twisted mass fermions including for the first time
also the flavour singlet decay constant. The Witten-Veneziano formula
represents a leading order expression in the framework of chiral perturbation
theory and we also employ leading order chiral perturbation theory to relate
the flavor singlet decay constant to the relevant decay constant parameters in
the quark flavor basis and flavor non-singlet decay constants. After taking the
continuum and the SU chiral limits we compare both sides and find good
agreement within uncertainties.Comment: 30 pages, 7 figures, version accepted for publicatio
Low CO Luminosities in Dwarf Galaxies
[Abridged] We present maps of CO 2-1 emission covering the entire
star-forming disks of 16 nearby dwarf galaxies observed by the IRAM HERACLES
survey. The data have 13 arcsec angular resolution, ~250 pc at our average
distance of 4 Mpc, and sample the galaxies by 10-1000 resolution elements. We
apply stacking techniques to perform the first sensitive search for CO emission
in dwarfs outside the Local Group ranging from single lines-of-sight, stacked
over IR-bright regions of embedded star formation, and stacked over the entire
galaxy. We detect 5 dwarfs in CO with total luminosities of L_CO = 3-28 1e6
Kkmspc2. The other 11 dwarfs remain undetected in CO even in the stacked data
and have L_CO < 0.4-8 1e6 Kkmspc2. We combine our sample of dwarfs with a large
literature sample of spirals to study scaling relations of L_CO with M_B and
metallicity. We find that dwarfs with metallicities of Z ~ 1/2-1/10 Z_sun have
L_CO about 1e2-1e4x smaller than spirals and that their L_CO per unit L_B is
10-100x smaller. A comparison with tracers of star formation (FUV and 24
micron) shows that L_CO per unit SFR is 10-100x smaller in dwarfs. One possible
interpretation is that dwarfs form stars much more efficiently, however we
argue that the low L_CO/SFR ratio is due to significant changes of the CO-to-H2
conversion factor, alpha_CO, in low metallicity environments. Assuming a
constant H2 depletion time of 1.8 Gyr (as found for nearby spirals) implies
alpha_CO values for dwarfs with Z ~ 1/2-1/10 Z_sun that are more than 10x
higher than those found in solar metallicity spirals. This significant increase
of alpha_CO at low metallicity is consistent with previous studies, in
particular those which model dust emission to constrain H2 masses. Even though
it is difficult to parameterize the metallicity dependence of alpha_CO, our
results suggest that CO is increasingly difficult to detect at lower
metallicities.Comment: Accepted for publication in the Astronomical Journal, 19 pages, 7
figure
{\eta} and {\eta}' mesons from Nf=2+1+1 twisted mass lattice QCD
We determine mass and mixing angles of eta and eta' states using Nf=2+1+1
Wilson twisted mass lattice QCD. We describe how those flavour singlet states
need to be treated in this lattice formulation. Results are presented for three
values of the lattice spacing, a=0.061 fm, a=0.078 fm and a=0.086 fm, with
light quark masses corresponding to values of the charged pion mass in a range
of 230 to 500 MeV and fixed bare strange and charm quark mass values. We obtain
557(15)(45) MeV for the eta mass (first error statistical, second systematic)
and 44(5) degrees for the mixing angle in the quark flavour basis,
corresponding to -10(5) degrees in the octet-singlet basis.Comment: 28 pages, 9 figures, version to appear in JHEP, extended discussion
of autocorrelation times and comparison to results available in the
literature, added a comment for FS-effects and clarified the description of
our blocking procedur
Cryogel-supported stem cell factory for customized sustained release of bispecific antibodies for cancer immunotherapy
Combining stem cells with biomaterial scaffolds provides a promising strategy for the development of drug delivery systems. Here we propose an innovative immunotherapeutic organoid by housing human mesenchymal stromal cells (MSCs), gene-modified for the secretion of an anti-CD33-anti-CD3 bispecific antibody (bsAb), in a small biocompatible star-shaped poly(ethylene glycol)-heparin cryogel scaffold as a transplantable and low invasive therapeutic machinery for the treatment of acute myeloid leukemia (AML). The macroporous biohybrid cryogel platform displays effectiveness in supporting proliferation and survival of bsAb-releasing-MSCs overtime in vitro and in vivo, avoiding cell loss and ensuring a constant release of sustained and detectable levels of bsAb capable of triggering T-cell-mediated anti-tumor responses and a rapid regression of CD33 + AML blasts. This therapeutic device results as a promising and safe alternative to the continuous administration of short-lived immunoagents and paves the way for effective bsAb-based therapeutic strategies for future tumor treatments
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Retargeting of UniCAR T cells with an in vivo synthesized target module directed against CD19 positive tumor cells
Recent treatments of leukemias with T cells expressing chimeric antigen receptors (CARs) underline their impressive therapeutic potential but also their risk of severe side effects including cytokine release storms and tumor lysis syndrome. In case of cross-reactivities, CAR T cells may also attack healthy tissues. To overcome these limitations, we previously established a switchable CAR platform technology termed UniCAR. UniCARs are not directed against typical tumor-associated antigens (TAAs) but instead against a unique peptide epitope: Fusion of this peptide epitope to a recombinant antibody domain results in a target module (TM). TMs can cross-link UniCAR T cells with tumor cells and thereby lead to their destruction. So far, we constructed TMs with a short half-life. The fast turnover of such a TM allows to rapidly interrupt the treatment in case severe side effects occur. After elimination of most of the tumor cells, however, longer lasting TMs which have not to be applied via continous infusion would be more convenient for the patient. Here we describe and characterize a TM for retargeting UniCAR T cells to CD19 positive tumor cells. Moreover, we show that the TM can efficiently be produced in vivo from producer cells housed in a sponge-like biomimetic cryogel and, thereby, serving as an in vivo TM factory for an extended retargeting of UniCAR T cells to CD19 positive leukemic cells