121 research outputs found
Phonon-Assisted Two-Photon Interference from Remote Quantum Emitters
Photonic quantum technologies are on the verge offinding applications in everyday life with quantum cryptography andquantum simulators on the horizon. Extensive research has beencarried out to identify suitable quantum emitters and single epitaxialquantum dots have emerged as near-optimal sources of bright, on-demand, highly indistinguishable single photons and entangledphoton-pairs. In order to build up quantum networks, it is essentialto interface remote quantum emitters. However, this is still anoutstanding challenge, as the quantum states of dissimilar“artificialatoms”have to be prepared on-demand with highfidelity and thegenerated photons have to be made indistinguishable in all possibledegrees of freedom. Here, we overcome this major obstacle and show an unprecedented two-photon interference (visibility of 51±5%) from remote strain-tunable GaAs quantum dots emitting on-demand photon-pairs. We achieve this result by exploiting forthefirst time the full potential of a novel phonon-assisted two-photon excitation scheme, which allows for the generation ofhighly indistinguishable (visibility of 71±9%) entangled photon-pairs (fidelity of 90±2%), enables push-button biexciton statepreparation (fidelity of 80±2%) and outperforms conventional resonant two-photon excitation schemes in terms of robustnessagainst environmental decoherence. Our results mark an important milestone for the practical realization of quantum repeatersand complex multiphoton entanglement experiments involving dissimilar artificial atom
Ultramafic clasts from the South Chamorro serpentine mud volcano reveal a polyphase serpentinization history of the Mariana forearc mantle
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Lithos 227 (2015): 1-20, doi:10.1016/j.lithos.2015.03.015.Serpentine seamounts located on the outer half of the pervasively fractured Mariana
forearc provide an excellent window into the forearc devolatilization processes, which
can strongly influence the cycling of volatiles and trace elements in subduction
zones. Serpentinized ultramafic clasts recovered from an active mud volcano in the
Mariana forearc reveal microstructures, mineral assemblages and compositions that
are indicative of a complex polyphase alteration history. Petrologic phase relations
and oxygen isotopes suggest that ultramafic clasts were serpentinized at
temperatures below 200 °C. Several successive serpe ntinization events represented
by different vein generations with distinct trace element contents can be recognized.
Measured Rb/Cs ratios are fairly uniform ranging between 1 and 10, which is
consistent with Cs mobilization from sediments at lower temperatures and lends
further credence to the low-temperature conditions proposed in models of the thermal structure in forearc settings. Late veins show lower fluid mobile element
(FME) concentrations than early veins, suggesting a deacreasing influence of fluid
discharge from sediments on the composition of the serpentinizing fluids. The
continuous microfabric and mineral chemical evolution observed in the ultramafic
clasts may have implications as to the origin and nature of the serpentinizing fluids.
We hypothesize that opal and smectite dehydration produce quartz-saturated fluids
with high FME contents and Rb/Cs between 1 and 4 that cause the early pervasive
serpentinization. The partially serpentinized material may then be eroded from the
basal plane of the suprasubduction mantle wedge. Serpentinization continued but the
interacting fluids did not carry the slab-flux signature, either because FME were no
longer released from the slab, or due to an en route loss of FMEs. Late chrysotile
veins that document the increased access of fluids in a now fluid-dominated regime
are characterized by reduced trace element contents with a slightly increased Rb/Cs
ratio near 10. This lack of geochemical slab signatures consistently displayed in all
late serpentinization stages may indicate that the slab-derived fluids have been
completely reset (i.e. the FME excesses were removed) by continued water-rock
reaction within the subduction channel. The final stage of diapiric rise of matrix and
clasts in the conduits is characterized by brucite-dominated alteration of the clasts
from the clast rim inward (independent of the intra-clast fabric relations), which
corresponds to re-equilibration with alkaline, low-silica activity fluids in the rising mud.This study was funded through a grant of the DFG to
WB (BA 1605/5-1)
Clinical Impact, Safety, and Efficacy of Single- versus Dual-Coil ICD Leads in MADIT-CRT
BACKGROUND: Current data on efficacy, safety and impact on clinical outcome of single- versus dual-coil implantable cardioverter-defibrillator (ICD) leads are limited and contradictory. METHODS: Defibrillation threshold (DFT) at implantation and first shock efficacy were compared in patients implanted with single- versus dual-coil ICD leads in MADIT-CRT. The risk for atrial tachyarrhythmias and all-cause mortality were evaluated. Short- (< 30 days after the implantation) and long-term (throughout the entire study duration) complications were assessed. RESULTS: Patients with dual-coil ICD leads had significantly lower DFTs compared to patients with single-coil ICD leads (17.6 +/- 5.8 J vs 19.4 +/- 6.1 J, P < 0.001). First shock efficacy was similar among patients with dual and single-coil ICD leads (89.6% vs 92.3%, P = 1.00). When comparing patients with dual versus single-coil ICD leads, there was no difference in the risk of atrial tachyarrhythmias (HR = 1.57, 95% CI: 0.81-3.02, P = 0.18), or in the risk of all-cause mortality (HR = 1.10, 95% CI: 0.58-2.07, P = 0.77). Patients implanted with single- or dual-coil ICD lead had similar short and long-term complication rates (short-term HR = 0.96, 95% CI: 0.56-1.65, P = 0.88, long-term procedure-related HR = 0.99, 95% CI: 0.62-1.59, P = 1.00, long-term ICD lead related: HR = 1.2, 95% CI: 0.5-2.9, P = 0.68) during the mean follow-up of 3.3 years. CONCLUSIONS: Patients with single-coil ICD leads have slightly higher DFTs compared to those with dual-coil leads, but the efficacy, safety, and clinical impact on atrial tachyarrhythmias, and mortality is similar. Implantation of single-coil ICD leads may be favorable in most patients
Longitudinal Analysis of Quality of Life, Clinical, Radiographic, Echocardiographic, and Laboratory Variables in Dogs with Myxomatous Mitral Valve Disease Receiving Pimobendan or Benazepril The QUEST Study
Development and evaluation of performance characteristics of timolol-loaded composite ocular films as potential delivery platform for treatment of glaucoma
Thin and erodible polymeric films were developed as potential ocular drug delivery systems to increase drug retention on the eye with the aim of improving bioavailability and achieving controlled drug release. Two biocompatible film forming polymers, hyaluronic acid (HA) and hydroxypropyl methylcellulose (HPMC), which are currently used as thickening agents in eye drops were employed. Two different films were prepared (i) as single polymer and (ii) as composite formulations by solvent casting method, incorporating glycerol (GLY) as plasticizer and timolol maleate (TM) as model glaucoma drug. After preliminary optimization of transparency and ease of handling, the formulations were further characterized for their physicochemical properties. No indication of significant drug-polymer or polymer-polymer (in composite films) interaction was observed from FTIR results while evaluation by IR mapping revealed uniform distribution of drug throughout the films. Amorphization of TM in the film matrix was confirmed by both DSC and XRD. Swelling studies illustrated remarkable swelling capacity of HA in comparison with HPMC which directly affected the drug release profiles, making HA a suitable polymer for controlled ocular drug delivery. Tensile and mucoadhesion properties confirmed higher elasticity and adhesiveness of HA while HPMC produced stronger films. The effect of sterilization by UV radiation on mechanical properties was also evaluated and showed no significant difference between the sterilized and non-sterilized films. The SEM results confirmed smoothness and homogeneity of film surfaces for all the formulations studied. The in vitro drug dissolution studies showed more extended release profiles of formulations containing HA. Cytotoxicity study (cell viability) using MTT assay on HeLa cells, confirmed that the single polymer and composite films are generally safe for ocular administration. The present work shows excellent film forming ability of HA and HPMC which can be used as single polymer or combined in composite formulations as potential topical ocular drug delivery platform to enhance drug retention on the ocular surface and therefore potential improved bioavailability
Cerebrospinal fluid markers of neuronal and glial cell damage in patients with autoimmune neurologic syndromes with and without underlying malignancies
Autoimmune neurologic syndromes can be paraneoplastic (associated with malignancies and/or onconeural antibodies), or non-paraneoplastic. Their clinical presentation is often similar. As prognosis is related to malignancy treatment, better biomarkers are needed to identify patients with malignancy. We investigated cerebrospinal fluid (CSF) markers of neuronal (neurofilament light chain, NFL and total tau protein, T-tau) and glial (glial fibrillary acidic protein) damage. CSF-NFL and T-tau were increased in both paraneoplastic and non-paraneoplastic autoimmune syndromes. Patients with manifest malignancies were older, had less epilepsy, more focal central and peripheral neurological signs and symptoms, and worse long-term outcome, than those without malignancy. CSF-NFL-levels predicted long-term outcome but were not diagnostic for malignancy, after age adjustment
Varicellovirus UL49.5 Proteins Differentially Affect the Function of the Transporter Associated with Antigen Processing, TAP
Cytotoxic T-lymphocytes play an important role in the protection against viral infections, which they detect through the recognition of virus-derived peptides, presented in the context of MHC class I molecules at the surface of the infected cell. The transporter associated with antigen processing (TAP) plays an essential role in MHC class I–restricted antigen presentation, as TAP imports peptides into the ER, where peptide loading of MHC class I molecules takes place. In this study, the UL49.5 proteins of the varicelloviruses bovine herpesvirus 1 (BHV-1), pseudorabies virus (PRV), and equine herpesvirus 1 and 4 (EHV-1 and EHV-4) are characterized as members of a novel class of viral immune evasion proteins. These UL49.5 proteins interfere with MHC class I antigen presentation by blocking the supply of antigenic peptides through inhibition of TAP. BHV-1, PRV, and EHV-1 recombinant viruses lacking UL49.5 no longer interfere with peptide transport. Combined with the observation that the individually expressed UL49.5 proteins block TAP as well, these data indicate that UL49.5 is the viral factor that is both necessary and sufficient to abolish TAP function during productive infection by these viruses. The mechanisms through which the UL49.5 proteins of BHV-1, PRV, EHV-1, and EHV-4 block TAP exhibit surprising diversity. BHV-1 UL49.5 targets TAP for proteasomal degradation, whereas EHV-1 and EHV-4 UL49.5 interfere with the binding of ATP to TAP. In contrast, TAP stability and ATP recruitment are not affected by PRV UL49.5, although it has the capacity to arrest the peptide transporter in a translocation-incompetent state, a property shared with the BHV-1 and EHV-1 UL49.5. Taken together, these results classify the UL49.5 gene products of BHV-1, PRV, EHV-1, and EHV-4 as members of a novel family of viral immune evasion proteins, inhibiting TAP through a variety of mechanisms
Bovine Herpesvirus Type 1 (BHV-1) UL49.5 Luminal Domain Residues 30 to 32 Are Critical for MHC-I Down-Regulation in Virus-Infected Cells
Bovine herpesvirus type 1 (BHV-1) UL49.5 inhibits transporter associated with antigen processing (TAP) and down-regulates cell-surface expression of major histocompatibility complex (MHC) class I molecules to promote immune evasion. We have constructed a BHV-1 UL49.5 cytoplasmic tail (CT) null and several UL49.5 luminal domain mutants in the backbone of wild-type BHV-1 or BHV-1 UL49.5 CT- null viruses and determined their relative TAP mediated peptide transport inhibition and MHC-1 down-regulation properties compared with BHV-1 wt. Based on our results, the UL49.5 luminal domain residues 30–32 and UL49.5 CT residues, together, promote efficient TAP inhibition and MHC-I down-regulation functions. In vitro, BHV-1 UL49.5 Δ30–32 CT-null virus growth property was similar to that of BHV-1 wt and like the wt UL49.5, the mutant UL49.5 was incorporated in the virion envelope and it formed a complex with gM in the infected cells
Sex-Specific Growth and Reproductive Dynamics of Red Drum in the Northern Gulf of Mexico
The Red Drum Sciaenops ocellatus stock is heavily targeted in the Gulf of Mexico (GOM) by recreational fishers and supports a small commercial fishery in Mississippi. Despite their popularity, little recent work has been done to describe their life history. In this work, we describe sex‐specific growth and reproductive dynamics of Red Drum collected from the northern GOM from September 2016 through October 2017. We evaluated seven candidate growth models and found that the three‐parameter von Bertalanffy growth function (VBGF) was the best candidate length‐at‐age model. No significant difference in growth between sexes was observed with the three‐parameter VBGF, despite the female‐specific curve having a larger mean asymptotic length than the male‐specific curve. All seven candidate growth models predicted similar mean length‐at‐age estimates, and four of them exhibited significant differences in sex‐specific mean length at age, with females reaching a larger length at age than males after age 5. There was no significant difference between the sex‐specific weight‐at‐length relationships. Red Drum are batch spawners that spawn in northern GOM coastal waters during August and September. We estimated 3.7 d between spawns and 10.5 spawning events per female in 2017. Nearly 20% of fish collected during the spawning season were sexually mature but reproductively inactive, indicating the possibility of skipped spawning. The age at 50% maturity was around 3 years (length at 50% maturity = 670 mm TL) in both sexes, but fish were not spawning capable until age 4.5 (703 mm TL) in males and age 5.8 (840 mm TL) in females. Furthermore, elevated gonadosomatic indices were not observed until around age 5–6. The updated life history information presented in this work helps to address current data limitations and provides critical information for future assessments of Red Drum stocks in the northern GOM
An Essential Role for the Proximal but Not the Distal Cytoplasmic Tail of Glycoprotein M in Murid Herpesvirus 4 Infection
Murid herpesvirus-4 (MuHV-4) provides a tractable model with which to define common, conserved features of gamma-herpesvirus biology. The multi-membrane spanning glycoprotein M (gM) is one of only 4 glycoproteins that are essential for MuHV-4 lytic replication. gM binds to gN and is thought to function mainly secondary envelopment and virion egress, for which several predicted trafficking motifs in its C-terminal cytoplasmic tail could be important. We tested the contribution of the gM cytoplasmic tail to MuHV-4 lytic replication by making recombinant viruses with varying C-terminal deletions. Removing an acidic cluster and a distal YXXΦ motif altered the capsid distribution somewhat in infected cells but had little effect on virus replication, either in vitro or in vivo. In contrast, removing a proximal YXXΦ motif as well completely prevented productive replication. gM was still expressed, but unlike its longer forms showed only limited colocalization with co-transfected gN, and in the context of whole virus appeared to support gN expression less well. We conclude that some elements of the gM cytoplasmic tail are dispensible for MuHV-4 replication, but the tail as a whole is not
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