1,267 research outputs found
Optimizing optical Bragg scattering for single-photon frequency conversion
We develop a systematic theory for optimising single-photon frequency
conversion using optical Bragg scattering. The efficiency and phase-matching
conditions for the desired Bragg scattering conversion as well as spurious
scattering and modulation instability are identified. We find that third-order
dispersion can suppress unwanted processes, while dispersion above the fourth
order limits the maximum conversion efficiency. We apply the optimisation
conditions to frequency conversion in highly nonlinear fiber, silicon nitride
waveguides and silicon nanowires. Efficient conversion is confirmed using full
numerical simulations. These design rules will assist the development of
efficient quantum frequency conversion between multicolour single photon
sources for integration in complex quantum networks.Comment: 9 pages, 14 figure
Recommended from our members
Shock Desensitization Effect in the STANAG 4363 Confined Explosive Component Water Gap Test
The Explosive Component Water Gap Test (ECWGT) in the Stanag 4363 has been recently investigated to assess the shock sensitivity of lead and booster components having a diameter less than 5 mm. For that purpose, Pentaerythritol Tetranitrate (PETN) based pellets having a height and diameter of 3 mm have been confined by a steel annulus of wall thickness 1-3.5 mm and with the same height as the pellet. 1-mm wall thickness makes the component more sensitive (larger gap). As the wall thickness is increased to 2-mm, the gap increases a lesser amount, but when the wall thickness is increased to 3.5-mm a decrease in sensitivity is observed (smaller gap). This decrease of the water gap has been reproduced experimentally by many nations. Numerical simulations using Ignition and Growth model have been performed in this paper and have reproduced the experimental results for the steel confinement up to 2 mm thick and aluminum confinement. A stronger re-shock following the first input shock from the water is focusing on the axis due to the confinement. The double shock configuration is well-known to lead in some cases to shock desensitization
The Batten disease protein CLN3 is important for stress granules dynamics and translational activity
The assembly of membrane-less organelles such as stress granules (SGs) is emerging as central in helping cells rapidly respond and adapt to stress. Following stress sensing, the resulting global translational shutoff leads to the condensation of stalled mRNAs and proteins into SGs. By reorganizing cytoplasmic contents, SGs can modulate RNA translation, biochemical reactions, and signaling cascades to promote survival until the stress is resolved. While mechanisms for SG disassembly are not widely understood, the resolution of SGs is important for maintaining cell viability and protein homeostasis. Mutations that lead to persistent or aberrant SGs are increasingly associated with neuropathology and a hallmark of several neurodegenerative diseases. Mutations in CLN3 are causative of juvenile neuronal ceroid lipofuscinosis, a rare neurodegenerative disease affecting children also known as Batten disease. CLN3 encodes a transmembrane lysosomal protein implicated in autophagy, endosomal trafficking, metabolism, and response to oxidative stress. Using a HeLa cell model lacking CLN3, we now show that CLN3KO is associated with an altered metabolic profile, reduced global translation, and altered stress signaling. Furthermore, loss of CLN3 function results in perturbations in SG dynamics, resulting in assembly and disassembly defects, and altered expression of the key SG nucleating factor G3BP1. With a growing interest in SG-modulating drugs for the treatment of neurodegenerative diseases, novel insights into the molecular basis of CLN3 Batten disease may reveal avenues for disease-modifying treatments for this debilitating childhood disease
Recommended from our members
One Year Term Review as a Participating Guest in the Detonator and Detonation Physics Group
The one year stay was possible after a long administrative process, because of the fact that this was the first participating guest of B division as a foreign national in HEAF (High Explosives Application Facility) with the Detonator/Detonation Physics Group
Microbiological, histological, immunological, and toxin response to antibiotic treatment in the mouse model of Mycobacterium ulcerans disease.
Mycobacterium ulcerans infection causes a neglected tropical disease known as Buruli ulcer that is now found in poor rural areas of West Africa in numbers that sometimes exceed those reported for another significant mycobacterial disease, leprosy, caused by M. leprae. Unique among mycobacterial diseases, M. ulcerans produces a plasmid-encoded toxin called mycolactone (ML), which is the principal virulence factor and destroys fat cells in subcutaneous tissue. Disease is typically first manifested by the appearance of a nodule that eventually ulcerates and the lesions may continue to spread over limbs or occasionally the trunk. The current standard treatment is 8 weeks of daily rifampin and injections of streptomycin (RS). The treatment kills bacilli and wounds gradually heal. Whether RS treatment actually stops mycolactone production before killing bacilli has been suggested by histopathological analyses of patient lesions. Using a mouse footpad model of M. ulcerans infection where the time of infection and development of lesions can be followed in a controlled manner before and after antibiotic treatment, we have evaluated the progress of infection by assessing bacterial numbers, mycolactone production, the immune response, and lesion histopathology at regular intervals after infection and after antibiotic therapy. We found that RS treatment rapidly reduced gross lesions, bacterial numbers, and ML production as assessed by cytotoxicity assays and mass spectrometric analysis. Histopathological analysis revealed that RS treatment maintained the association of the bacilli with (or within) host cells where they were destroyed whereas lack of treatment resulted in extracellular infection, destruction of host cells, and ultimately lesion ulceration. We propose that RS treatment promotes healing in the host by blocking mycolactone production, which favors the survival of host cells, and by killing M. ulcerans bacilli
Magnetic fields in noncommutative quantum mechanics
We discuss various descriptions of a quantum particle on noncommutative space
in a (possibly non-constant) magnetic field. We have tried to present the basic
facts in a unified and synthetic manner, and to clarify the relationship
between various approaches and results that are scattered in the literature.Comment: Dedicated to the memory of Julius Wess. Work presented by F. Gieres
at the conference `Non-commutative Geometry and Physics' (Orsay, April 2007
Fiber optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy
We present a synchronously pumped fiber optical parametric oscillator for coherent anti-Stokes Raman scattering microscopy. Pulses from a 1 μm Yb-doped fiber laser are amplified and frequency converted to 779–808 nm through normal dispersion four-wave mixing in a photonic crystal fiber. The idler frequency is resonant in the oscillator cavity, and we find that bandpass filtering the feedback is essential for a stable, narrow-bandwidth output. Experimental results agree quite well with numerical simulations of the device. Transform-limited 2 ps pulses with energy up to 4 nJ can be generated at the signal wavelength. The average power is 180 mW, and the relative-intensity noise is much lower than that of a similar parametric amplifier. High-quality coherent Raman images of mouse tissues recorded with this source are presented
Mucosal CD8 T Cell Responses Are Shaped by Batf3-DC After Foodborne Listeria monocytogenes Infection
While immune responses have been rigorously examined after intravenous Listeria monocytogenes (Lm) infection, less is understood about its dissemination from the intestines or the induction of adaptive immunity after more physiologic models of foodborne infection. Consequently, this study focused on early events in the intestinal mucosa and draining mesenteric lymph nodes (MLN) using foodborne infection of mice with Lm modified to invade murine intestinal epithelium (InlAM Lm). InlAM Lm trafficked intracellularly from the intestines to the MLN and were associated with Batf3-independent dendritic cells (DC) in the lymphatics. Consistent with this, InlAM Lm initially disseminated from the gut to the MLN normally in Batf3–/– mice. Activated migratory DC accumulated in the MLN by 3 days post-infection and surrounded foci of InlAM Lm. At this time Batf3–/– mice displayed reduced InlAM Lm burdens, implicating cDC1 in maximal bacterial accumulation in the MLN. Batf3–/– mice also exhibited profound defects in the induction and gut-homing of InlAM Lm-specific effector CD8 T cells. Restoration of pathogen burden did not rescue antigen-specific CD8 T cell responses in Batf3–/– mice, indicating a critical role for Batf3 in generating anti-InlAM Lm immunity following foodborne infection. Collectively, these data suggest that DC play diverse, dynamic roles in the early events following foodborne InlAM Lm infection and in driving the establishment of intestinal Lm-specific effector T cells.Fil: Imperato, Jessica Nancy. Stony Brook University Renaissance School Of Medicine; Estados UnidosFil: Xu, Daqi. Uconn Health; Estados UnidosFil: Romagnoli, Pablo Alberto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Investigacion Medica Mercedes y Martin Ferreyra. Grupo Vinculado Centro de Investigacion En Medicina Traslacional Severo R. Amuchastegui - Cimetsa | Universidad Nacional de Cordoba. Instituto de Investigacion Medica Mercedes y Martin Ferreyra. Grupo Vinculado Centro de Investigacion En Medicina Traslacional Severo R. Amuchastegui - Cimetsa | Instituto de Investigacion Medica Mercedes y Martin Ferreyra. Instituto de Investigacion Medica Mercedes y Martin Ferreyra. Grupo Vinculado Centro de Investigacion En Medicina Traslacional Severo R. Amuchastegui - Cimetsa.; ArgentinaFil: Qiu, Zhijuan. Stony Brook University Renaissance School Of Medicine; Estados UnidosFil: Perez, Pedro. Stony Brook University Renaissance School Of Medicine; Estados UnidosFil: Khairallah, Camille. Stony Brook University Renaissance School Of Medicine; Estados UnidosFil: Pham, Quynh Mai. Uconn Health; Estados UnidosFil: Andrusaite, Anna. University of Glasgow; Reino UnidoFil: Bravo Blas, Alberto. The Beatson Institute For Cancer Research; Reino UnidoFil: Milling, Simon W. F.. University of Glasgow; Reino UnidoFil: Lefrancois, Leo. Uconn Health; Estados UnidosFil: Khanna, Kamal M.. University of New York; Estados UnidosFil: Puddington, Lynn. Uconn Health; Estados UnidosFil: Sheridan, Brian S.. Stony Brook University Renaissance School Of Medicine; Estados Unido
Observation of resonances consistent with pentaquark states in decays
Observations of exotic structures in the channel, that we refer to
as pentaquark-charmonium states, in decays are
presented. The data sample corresponds to an integrated luminosity of 3/fb
acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude
analysis is performed on the three-body final-state that reproduces the
two-body mass and angular distributions. To obtain a satisfactory fit of the
structures seen in the mass spectrum, it is necessary to include two
Breit-Wigner amplitudes that each describe a resonant state. The significance
of each of these resonances is more than 9 standard deviations. One has a mass
of MeV and a width of MeV, while the second
is narrower, with a mass of MeV and a width of MeV. The preferred assignments are of opposite parity, with one
state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after
referee's comments, now 19 figure
A lysosomal enigma CLN5 and its significance in understanding neuronal ceroid lipofuscinosis
Neuronal Ceroid Lipofuscinosis (NCL), also known as Batten disease, is an incurable childhood brain disease. The thirteen forms of NCL are caused by mutations in thirteen CLN genes. Mutations in one CLN gene, CLN5, cause variant late-infantile NCL, with an age of onset between 4 and 7 years. The CLN5 protein is ubiquitously expressed in the majority of tissues studied and in the brain, CLN5 shows both neuronal and glial cell expression. Mutations in CLN5 are associated with the accumulation of autofluorescent storage material in lysosomes, the recycling units of the cell, in the brain and peripheral tissues. CLN5 resides in the lysosome and its function is still elusive. Initial studies suggested CLN5 was a transmembrane protein, which was later revealed to be processed into a soluble form. Multiple glycosylation sites have been reported, which may dictate its localisation and function. CLN5 interacts with several CLN proteins, and other lysosomal proteins, making it an important candidate to understand lysosomal biology. The existing knowledge on CLN5 biology stems from studies using several model organisms, including mice, sheep, cattle, dogs, social amoeba and cell cultures. Each model organism has its advantages and limitations, making it crucial to adopt a combinatorial approach, using both human cells and model organisms, to understand CLN5 pathologies and design drug therapies. In this comprehensive review, we have summarised and critiqued existing literature on CLN5 and have discussed the missing pieces of the puzzle that need to be addressed to develop an efficient therapy for CLN5 Batten disease
- …