We consider the fidelity of the vector meson dominance (VMD) assumption as an instrument for relating the electromagnetic vector-meson production reaction
e
+
p
→
e
′
+
V
+
p
to the purely hadronic ...process
V
+
p
→
V
+
p
. Analyses of the photon vacuum polarisation and the photon-quark vertex reveal that such a VMD
Ansatz
might be reasonable for light vector-mesons. However, when the vector-mesons are described by momentum-dependent bound-state amplitudes, VMD fails for heavy vector-mesons: it cannot be used reliably to estimate either a photon-to-vector-meson transition strength or the momentum dependence of those integrands that would arise in calculations of the different reaction amplitudes. Consequently, for processes involving heavy mesons, the veracity of both cross-section estimates and conclusions based on the VMD assumption should be reviewed, e.g., those relating to hidden-charm pentaquark production and the origin of the proton mass.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background and purpose
Previous studies suggested that the overall burden of prior infections contributes to cardiovascular diseases and stroke. In the present study, the association between ...infectious burden (IB) and Alzheimer's disease (AD) was examined.
Methods
Antibody titers to common infectious pathogens including cytomegalovirus (CMV), herpes simplex virus type 1 (HSV‐1), Borrelia burgdorferi, Chlamydophila pneumoniae and Helicobacter pylori were measured by enzyme‐linked immunosorbent assay in 128 AD patients and 135 healthy controls. IB was defined as a composite serological measure of exposure to these common pathogens.
Results
Seropositivities toward zero−two, three and four−five of these pathogens were found in 44%, 40% and 16% of healthy controls but in 20%, 44% and 36% of AD patients, respectively. IB, bacterial burden and viral burden were independently associated with AD after adjusting for age, gender, education, APOE genotype and various comorbidities. Mini‐Mental State Examination scores were negatively correlated with IB in all cases. Serum beta‐amyloid protein (Aβ) levels (i.e. Aβ40, Aβ42 and total Aβ) and inflammatory cytokines (i.e. interferon‐γ, tumor necrosis factor α, interleukin‐1β and interleukin‐6) in individuals exposed to four−five infectious pathogens were significantly higher than those exposed to zero−two or three pathogens.
Conclusions
IB consisting of CMV, HSV‐1, B. burgdorferi, C. pneumoniae and H. pylori is associated with AD. This study supports the role of infection/inflammation in the etiopathogenesis of AD.
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Exploiting crossing symmetry, the hadron scale pion valence quark distribution function is used to predict the kindred elementary valence quark fragmentation function (FF). This function defines the ...kernel of a quark jet fragmentation equation, which is solved to obtain the full pion FFs. After evolution to a scale typical of FF fits to data, the results for quark FFs are seen to compare favourably with such fits. However, the gluon FF is markedly different. Notably, although FF evolution equations do not themselves guarantee momentum conservation, inclusion of a gluon FF which, for four quark flavours, distributes roughly 11% of the total light-front momentum fraction, is sufficient to restore momentum conservation under evolution. Overall, significant uncertainty is attached to FFs determined via fits to data; hence, the features of the predictions described herein could potentially provide useful guidance for future such studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The progress in the field of graphene has aroused a renaissance of keen research interest in layered transition metal dichalcogenides (TMDs). Tungsten disulfide (WS2), a typical TMD with favorable ...semiconducting band gap and strong light-matter interaction, exhibits great potential for highly-responsive photodetection. However, WS2-based photodetection is currently unsatisfactory due to the low optical absorption (2%-10%) and poor carrier mobility (0.01-0.91 cm(2) V(-1) s(-1)) of the thin WS2 layers grown by chemical vapor deposition (CVD). Here, we introduce pulsed-laser deposition (PLD) to prepare multilayered WS2 films. Large-area WS2 films of the magnitude of cm(2) are achieved. Comparative measurements of a WS2-based photoresistor demonstrate its stable broadband photoresponse from 370 to 1064 nm, the broadest range demonstrated in WS2 photodetectors. Benefiting from the large optical absorbance (40%-85%) and high carrier mobility (31 cm(2) V(-1) s(-1)), the responsivity of the device approaches a high value of 0.51 A W(-1) in an ambient environment. Such a performance far surpasses the CVD-grown WS2-based photodetectors (μA W(-1)). In a vacuum environment, the responsivity is further enhanced to 0.70 A W(-1) along with an external quantum efficiency of 137% and a photodetectivity of 2.7 × 10(9) cm Hz(1/2) W(-1). These findings stress that the PLD-grown WS2 film may constitute a new paradigm for the next-generation stable, broadband and highly-responsive photodetectors.
Our review provides a comprehensive overview on the latest progress in pulsed-laser deposition (PLD) of 2D layered materials (2DLMs), and its application in photoelectric detection. We begin with a ...retrospective overview on various 2DLMs and their development in photoelectric detection. Then we present the fundamentals of PLD and its unique advantages compared with the traditional growth methods. Subsequently, the PLD growth of 2DLMs and the influence of various parameters are discussed. After this, we describe the current metal-semiconductor-metal and vertical heterojunction photodetectors that incorporate the PLD-grown 2DLMs. This leads into a summary of the strategies used to improve the photosensitivity and in-depth insights into the working mechanism. We then present the PLD-fabricated transparent and flexible 2DLM photodetectors. Finally, we highlight the unresolved issues and propose the future directions in this emerging research field.
In recent years, owing to the significant applications of health monitoring, wearable electronic devices such as smart watches, smart glass and wearable cameras have been growing rapidly. Gas sensor ...is an important part of wearable electronic devices for detecting pollutant, toxic, and combustible gases. However, in order to apply to wearable electronic devices, the gas sensor needs flexible, transparent, and working at room temperature, which are not available for traditional gas sensors. Here, we for the first time fabricate a light-controlling, flexible, transparent, and working at room-temperature ethanol gas sensor by using commercial ZnO nanoparticles. The fabricated sensor not only exhibits fast and excellent photoresponse, but also shows high sensing response to ethanol under UV irradiation. Meanwhile, its transmittance exceeds 62% in the visible spectral range, and the sensing performance keeps the same even bent it at a curvature angle of 90(o). Additionally, using commercial ZnO nanoparticles provides a facile and low-cost route to fabricate wearable electronic devices.
A symmetry-preserving continuum approach to meson bound states in quantum field theory, employed elsewhere to describe numerous π- and K-meson electroweak processes, is used to analyze leptonic and ...semileptonic decays of D(s) mesons. Each semileptonic transition is conventionally characterized by the value of the dominant form factor at t = 0 and the following results are obtained herein: f+Ds→K ( 0 ) = 0.673 ( 40 ) ; f+ D→π+ ( 0 ) = 0.618 ( 31 ) and f+ D→K ( 0 ) = 0.756 (36). Working with the computed t -dependence of these form factors and standard averaged values for | Vcd |, | Vcs|, one arrives at the following predictions for the associated branching fractions: BD+s → K0e+νe = 3.31 ( 33 ) × 10−3, BD0→e+νe = 2.73 ( 22 ) × 10−3, and BD0→K−e+νe = 3.83 ( 28 ) %. Alternatively, using the calculated t -dependence, agreement with contemporary empirical results for these branching fractions requires | Vcd | = 0.221 ( 9 ), | Vus | = 0.953 ( 34 ) . With all D(s) transition form factors in hand, the nature of SU(3)-flavor symmetry breaking in this array of processes can be analysed; and just as in the π−K sector, the magnitude of such effects is found to be determined by the scales associated with emergent mass generation in the Standard Model, not those originating with the Higgs mechanism.
A temperature sensor based on photonic crystal fiber (PCF) surface plasmon resonance (SPR) is proposed in this paper. We use the dual function of the PCF filled with different concentrations of ...analyte and silver nanowires to realize temperature sensing. The proposed sensor has been analyzed through numerical simulations and demonstrated by experiments. The results of the simulations and experiments show that a blue shift will be obtained with the temperature increase, and different concentrations will change the resonance wavelength and confinement loss. Temperature sensitivity is as high as 2.7 nm/°C with the experiment, which can provide a reference for the implementation and application of a PCF-based SPR temperature sensor or other PCF-based SPR sensing.
The amyloid-β protein (Aβ) protein plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). It is believed that Aβ deposited in the brain originates from the brain tissue itself. ...However, Aβ is generated in both brain and peripheral tissues. Whether circulating Aβ contributes to brain AD-type pathologies remains largely unknown. In this study, using a model of parabiosis between APPswe/PS1dE9 transgenic AD mice and their wild-type littermates, we observed that the human Aβ originated from transgenic AD model mice entered the circulation and accumulated in the brains of wild-type mice, and formed cerebral amyloid angiopathy and Aβ plaques after a 12-month period of parabiosis. AD-type pathologies related to the Aβ accumulation including tau hyperphosphorylation, neurodegeneration, neuroinflammation and microhemorrhage were found in the brains of the parabiotic wild-type mice. More importantly, hippocampal CA1 long-term potentiation was markedly impaired in parabiotic wild-type mice. To the best of our knowledge, our study is the first to reveal that blood-derived Aβ can enter the brain, form the Aβ-related pathologies and induce functional deficits of neurons. Our study provides novel insight into AD pathogenesis and provides evidence that supports the development of therapies for AD by targeting Aβ metabolism in both the brain and the periphery.
Jupiter's auroral emission is a spectacular phenomenon that provides insight into energy release processes related to the coupling of its magnetosphere and ionosphere. This energy release is ...influenced by solar wind conditions. Using joint observations from Juno and the Hubble Space Telescope (HST), we statistically investigate the relationship between auroral power and current sheet variations under different solar wind conditions. In this study, we reveal that during global main auroral brightening events that are closely connected to solar wind compressions, the dawn side current sheet is substantially thinner than during times when a quiet auroral morphology is present. Furthermore, the total current intensity in the current sheet is found to increase under solar wind compression conditions compared to the quiet period. These findings provide important observational evidence for how magnetospheric dynamics driven by solar wind behavior affect auroral activity, deepening our understanding of the coupling between Jupiter's magnetosphere and ionosphere.
Plain Language Summary
Jupiter, the largest planet in our solar system, has a fascinating and powerful auroral emission that can help us understand the interactions between its magnetic field and the charged particles in its atmosphere. These auroral emissions are influenced by solar wind conditions, which are streams of charged particles coming from the Sun. In this study, we used observations from the Juno spacecraft and the Hubble Space Telescope to investigate the relationship between Jupiter's auroral emissions and changes in the planet's magnetic field. We found that during periods of increased solar wind pressure, the magnetic field layer, known as the current sheet, becomes thinner compared to times when the aurora is quiet. These findings offer valuable evidence of how Jupiter's magnetic field is affected by solar wind behavior and improve our understanding of the relationship between the planet's magnetic field and its aurora. This research helps us better comprehend the complex processes occurring in Jupiter's magnetosphere and can potentially enhance our knowledge of similar phenomena occurring on other planets.
Key Points
The features of the current sheet in Jupiter's dawnside magnetosphere are highly relevant to auroral contexts
During a solar wind compression event, the dawnside current sheet becomes substantially thinner than during quiet times
The total current intensity of the current sheet is much higher during solar wind compression events than the quiet times
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