An outstanding goal in quantum optics and scalable photonic quantum technology is to develop a source that each time emits one and only one entangled photon pair with simultaneously high entanglement ...fidelity, extraction efficiency, and photon indistinguishability. By coherent two-photon excitation of a single InGaAs quantum dot coupled to a circular Bragg grating bull's-eye cavity with a broadband high Purcell factor of up to 11.3, we generate entangled photon pairs with a state fidelity of 0.90(1), pair generation rate of 0.59(1), pair extraction efficiency of 0.62(6), and photon indistinguishability of 0.90(1) simultaneously. Our work will open up many applications in high-efficiency multiphoton experiments and solid-state quantum repeaters.
Nanofibers are attractive supporting matrices for catalytically active metallic catalysts. Herein, palladium species were successfully incorporated into the modified chitosan/poly(ethylene ...oxide)/maleic acid nanofibers by electrospinning. Then, the hybrid nanofibers were thermally cross-linked at elevated temperature to improve stable behavior in solution. X-ray diffraction and transmission electron microscopy characterizations show that the palladium nanoparticles are dispersed uniformly inside the hybrid nanofibers. This novel hybrid nanofiber mat displayed high catalytic activity for the Sonogashira coupling reaction of phenyl acetylene with aromatic iodides under copper free condition with moderate to excellent yields. Moreover, this nanofiber mat could be reused 10 times with little activity loss. Thus, we have proposed a facile way to prepare highly active and stable heterogeneous palladium catalyst.
The periodic activity of the repeating fast radio burst (FRB) 180916.J0158+65 was recently reported by the CHIME/FRB Collaboration team. From this source 28 bursts not only show a ∼16 day period with ...an active phase of ∼4.0 days, but they also exhibit a broken power law in differential energy distribution. In this Letter, we suggest that FRB 180916.J0158+65-like periodic FRBs could provide a unique probe of extragalactic asteroid belts (EABs), based on our previously proposed pulsar-EAB impact model, in which repeating FRBs arise from an old-aged, slowly spinning, moderately magnetized pulsar traveling through an EAB around another stellar-mass object. These two objects form a binary, and thus the observed period is in fact the orbital period. We show that this model can be used to well interpret all of the observed data of FRB 180916.J0158+65. Furthermore, we constrain the EAB's physical properties and find that (1) the outer radius of the EAB is at least an order of magnitude smaller than that of its analog in the solar system, (2) the differential size distribution of the EAB's asteroids at small diameters (large diameters) is shallower (steeper) than that of solar system small objects, and (3) the two belts have a comparable mass.
Viscous dissipative heating has long been discussed as a heat source in solid celestial bodies experiencing exogenic forces such as tidal forcing or surface loading. We examine the characteristics of ...viscous dissipative heating in a Newtonian, Maxwell viscoelastic solid in a 2D Cartesian box subjected to a surface load. The solutions are analyzed to understand the general controls on the energetics of planetary mantle that are associated with exogenic forcing. We find that work done at the surface is partitioned between dissipative and elastic terms depending on mantle viscosity, loading period, and loading wavelength. For viscosity structures with a weak upper mantle layer, dissipation is spatially concentrated in the upper mantle for short loading periods, implying that exogenic forces may play a role in the generation of weak upper mantle layers. The results are also scaled to estimate how much energy is dissipated in Earth's mantle, both present and past, during surface mass movement processes and tidal forcing. We find that the dissipation from glacial loading cycles since Mid‐Pleistocene at a period of 100,000 years might contribute ∼3 mW/m2 heat flux in the formerly glaciated regions, but for glacial cycles with a period of 40,000 years during the Early Pleistocene, the heat flux may have been 3 times larger at ∼9 mW/m2. We find that tidal forcing for the early Earth at 4 Ga may have contributed ∼30 TW of heat to the upper mantle, suggesting that exogenic forces have the capacity to contribute significantly to early Earth's energy budget.
Plain Language Summary
Heat in the interior of solid planets and moons comes from three main sources: heat from formation, heat from the decay of radioactive elements, and energy dissipated as heat when mantle material is deformed by external forces. In this study, we use a simple 2‐dimensional model to characterize heat generated by viscous dissipation resulting from a surface loading force. We examine how dissipative heating behaves under different loading conditions and in materials with different viscosity structures in order to understand the general controls on dissipative heating in solid celestial bodies. We also scale our results to estimate how much heat might be generated on Earth during climate processes, such as glaciation and de‐glaciation, and during tidal deformation. Our results suggest that in some cases, heat from external forces may strongly influence mantle dynamics and even influence the dynamic formation of layered viscosity structures. On Earth in particular, heat generated by tidal forcing around 4 billion years ago was potentially of large enough magnitude to contribute significantly to interior heat and influence the dynamics of the mantle.
Key Points
Work done at the surface of a viscoelastic solid is always balanced by energy stored elastically and energy dissipated as heat
At short loading periods, dissipation is most often spatially concentrated in weak upper mantle layers
At certain times, tidal forcing and climate forced mass movement may have contributed significantly to Earth's energy budget
Background. Previous studies have shown that common human coronavirus might be neurotropic, although it was first isolated as a pathogen of the respiratory tract. We noticed that a few patients with ...severe acute respiratory syndrome (SARS) experienced central nervous symptoms during the course of illness. In the present study, we isolated a SARS coronavirus strain from a brain tissue specimen obtained from a patient with SARS with significant central nervous symptoms. Methods. Using transmission electronic microscopy and nested reverse transcription–polymerase chain reaction, the causative pathogen was identified in cultures of a brain tissue specimen obtained from the patient with SARS. Histopathologic examination of the brain tissue was performed using the methods of immunohistochemistry analysis and double immunofluorescence staining. Fifteen cytokines and chemokines were detected in the blood of the patient with SARS by means of a bead-based multiassay system. Results. A fragment specific for SARS human coronavirus was amplified from cultures of the brain suspension, and transmission electronic microscopy revealed the presence of an enveloped virus morphologically compatible with a coronavirus isolated in the cultures. Pathologic examination of the brain tissue revealed necrosis of neuron cells and broad hyperplasia of gliocytes. Immunostaining demonstrated that monokine induced by interferon-Γ (Mig) was expressed in gliocytes with the infiltration of CD68+ monocytes/macrophages and CD3+ T lymphocytes in the brain mesenchyme. Cytokine/chemokine assay revealed that levels of interferon-Γ–inducible protein 10 and Mig in the blood were highly elevated, although the levels of other cytokines and chemokines were close to normal. Conclusions. This study provides direct evidence that SARS human coronavirus is capable of infecting the central nervous system, and that Mig might be involved in the brain immunopathology of SARS.
Photoionization in the time and frequency domain Isinger, M.; Squibb, R. J.; Busto, D. ...
Science (American Association for the Advancement of Science),
11/2017, Letnik:
358, Številka:
6365
Journal Article
Recenzirano
Odprti dostop
Ultrafast processes in matter, such as the electron emission after light absorption, can now be studied using ultrashort light pulses of attosecond duration (10−18 seconds) in the extreme ultraviolet ...spectral range. The lack of spectral resolution due to the use of short light pulses has raised issues in the interpretation of the experimental results and the comparison with theoretical calculations. We determine photoionization time delays in neon atoms over a 40–electron volt energy range with an interferometric technique combining high temporal and spectral resolution. We spectrally disentangle direct ionization from ionization with shake-up, in which a second electron is left in an excited state, and obtain excellent agreement with theoretical calculations, thereby solving a puzzle raised by 7-year-old measurements.
Breast cancer‐related lymphoedema (BCRL) is a common sequela of surgical or radiation therapy of breast cancer. Although being an important part of conservative therapy, the role of manual lymphatic ...drainage (MLD) on BCRL is still debating. The objective of the current systematic review and meta‐analysis was to determine whether the addition of MLD to the standard therapy (ST) could manage BCRL more effectively. We searched PubMed, EMBASE and Cochrane Library for related randomised clinical trials to compare the volume reduction, improvement of symptoms and arm function between groups with or without MLD. Four randomised controlled trials, with 234 patients, were included. Results showed there was a significant difference in volume reduction between MLD plus routine treatment and sole routine treatment. Current trials show that adding MLD to the ST could enhance the effectiveness of treating volume reduction of lymphoedema, but might not improve subjective symptoms or arm function.
One of the major applications of tissue‐engineered skin substitutes for wound healing is to promote the healing of cutaneous wounds. In this respect, many important clinical milestones have been ...reached in the past decades. However, currently available skin substitutes for wound healing often suffer from a range of problems including wound contraction, scar formation, and poor integration with host tissue. Engineering skin substitutes by tissue engineering approach has relied upon the creation of three‐dimensional scaffolds as extracellular matrix (ECM) analog to guide cell adhesion, growth, and differentiation to form skin‐functional and structural tissue. The three‐dimensional scaffolds can not only cover wound and give a physical barrier against external infection as wound dressing, but also can provide support both for dermal fibroblasts and the overlying keratinocytes for skin tissue engineering. A successful tissue scaffold should exhibit appropriate physical and mechanical characteristics and provide an appropriate surface chemistry and nano and microstructures to facilitate cellular attachment, proliferation, and differentiation. A variety of scaffolds have been fabricated based on materials ranging from naturally occurring ones to those manufactured synthetically. This review discusses a variety of commercial or laboratory‐engineered skin substitutes for wound healing. Central to the discussion are the scaffolds/materials, fabrication techniques, and their characteristics associated with wound healing. One specifically highlighted emerging fabrication technique is electrospinning that allows the design and fabrication of biomimetic scaffolds that offer tremendous potential applications in wound healing of skin. WIREs Nanomed Nanobiotechnol 2010 2 510–525
This article is categorized under:
Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Background Most reported sporotrichosis cases came from South American countries, the USA, India and Japan. This mycosis is also endemic in Northeast China. However, the situation is not clear for ...international researchers due to lack of large series reported in English.
Objectives To report and analyse 457 sporotrichosis cases.
Methods Retrospective study of 457 cases of sporotrichosis diagnosed by fungal culture at the First Hospital of Jilin University from 1 January 2007 to 31 December 2009.
Results In this series, the male: female ratio was 1:1.42. Mean age was 41.2 years. Cases from age group 51–60 years accounted for most of the cases (22.54%). A total of 434 patients lived in rural areas (94.97%). The onset of symptoms in 67.61% cases happened in cold seasons (winter and spring). History of trauma presented in 133 cases (29.1%). The mean duration of the symptoms before the presentation was 6.41 months. A total of 190 (41.58%) showed lymphocutaneous form, 252 patients (55.14%) showed fixed form, 8 patients (1.75%) showed disseminated cutaneous sporotrichosis and the clinical form of 7 patients (1.53%) could not be defined. Extremities and nodules were the most frequently involved sites and founded manifestation. Main histopathology findings were suppurative granuloma, tuberculoid granuloma and mixed inflammatory granuloma. A total of 75 cases (19.74%) had fungal elements revealed by Periodic Acid‐Schiff staining. Patients responded well to potassium iodide (KI), itraconazole, terbinafine and combinations of these agents with a mean course of 2.17 months to resolve.
Conclusion As the first report of a large series of sporotrichosis cases from China to be published in English literature, our study indicated a serious sporotrichosis endemic situation in Jilin province, Northeast China, with epidemiological and clinical characteristics similar to those of previous Chinese reports, but different from those in other countries. KI, itraconazole and terbinafine are effective for the treatment.
Acute allergic symptoms are caused by allergen-induced crosslinking of allergen-specific immunoglobulin E (IgE) bound to Fc-epsilon receptors on effector cells. Desensitization with allergen-specific ...immunotherapy (SIT) has been used for over a century, but the dominant protective mechanism remains unclear. One consistent observation is increased allergen-specific IgG, thought to competitively block allergen binding to IgE. Here we show that the blocking potency of the IgG response to Cat-SIT is heterogeneous. Next, using two potent, pre-selected allergen-blocking monoclonal IgG antibodies against the immunodominant cat allergen Fel d 1, we demonstrate that increasing the IgG/IgE ratio reduces the allergic response in mice and in cat-allergic patients: a single dose of blocking IgG reduces clinical symptoms in response to nasal provocation (ANCOVA, p = 0.0003), with a magnitude observed at day 8 similar to that reported with years of conventional SIT. This study suggests that simply augmenting the blocking IgG/IgE ratio may reverse allergy.
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