47 research outputs found
Multi-messenger Study of Galactic Diffuse Emission with LHAASO and IceCube Observations
With the breakthrough in PeV gamma-ray astronomy brought by the LHAASO
experiment, the high-energy sky is getting richer than before. Lately, LHAASO
Collaboration reported the observation of a gamma-ray diffuse emission with
energy up to the PeV level from both the inner and outer Galactic plane. In
these spectra, there is one bump that is hard to explain by the conventional
cosmic-ray transport scenarios. Therefore, we introduce two extra components
corresponding to unresolved sources with exponential-cutoff-power-law (ECPL)
spectral shape, one with an index of 2.4, and 20 TeV cutoff energy, and another
with index of 2.3 and 2 PeV cutoff energy. With our constructed model, we
simulate the Galactic diffuse neutrino flux and find our results are in full
agreement with the latest IceCube Galactic plane search. We estimate the
Galactic neutrino contributes of of astrophysical neutrinos at 20
TeV. In the high-energy regime, as expected most of the neutrinos observed by
IceCube should be from extragalactic environments.Comment: 10 pages, 8 figures, comments are welcome, accepted by PR
A New Scenario of Solar Modulation Model during the Polarity Reversing
When the Galactic Cosmic Rays (GCRs) entering the heliosphere, they encounter
the solar wind plasma, and their intensity is reduced, so-called solar
modulation. The modulation is caused by the combination of a few factors, such
as particle energies, solar activity and solar disturbance. In this work, a 2D
numerical method is adopted to simulate the propagation of GCRs in the
heliosphere with SOLARPROP, and to overcome the time-consuming issue, the
machine learning technique is also applied. With the obtained proton local
interstellar spectra (LIS) based on the observation from Voyager 1 and AMS-02,
the solar modulation parameters during the solar maximum activity of cycle 24
have been found. It shows the normalization and index of the diffusion
coefficient indeed reach a maximal value in February 2014. However, after
taking into account the travel time of particles with different energies, the
peak time was found postponed to November 2014 as expected. The nine-month late
is so-called time lag.Comment: 10 pages, 8 figure
Compound dietary fiber and high-grade protein diet improves glycemic control and ameliorates diabetes and its comorbidities through remodeling the gut microbiota in mice
Dietary intervention with a low glycemic index and full nutritional support is emerging as an effective strategy for diabetes management. Here, we found that the treatment of a novel compound dietary fiber and high-grade protein diet (CFP) improved glycemic control and insulin resistance in streptozotocin-induced diabetic mice, with a similar effect to liraglutide. In addition, CFP treatment ameliorated diabetes-related metabolic syndromes, such as hyperlipidemia, hepatic lipid accumulation and adipogenesis, systemic inflammation, and diabetes-related kidney damage. These results were greatly associated with enhanced gut barrier function and altered gut microbiota composition and function, especially those bacteria, microbial functions, and metabolites related to amino acid metabolism. Importantly, no adverse effect of CFP was found in our study, and CFP exerted a wider arrange of protection against diabetes than liraglutide. Thereby, fortification with balanced dietary fiber and high-grade protein, like CFP, might be an effective strategy for the management and treatment of diabetes
A New Scenario of Solar Modulation Model during the Polarity Reversing
When entering the heliosphere, galactic cosmic rays (GCRs) will encounter the solar wind plasma, reducing their intensity. This solar modulation effect is strongly affected by the structure of the solar wind and the heliospheric magnetic field (HMF). To address the effect during the solar maximum of cycle 24, we study the solar modulation under a scenario in which the weights for A = ±1 are determined by the structure of HMF, and the traveling time of GCRs simulated by SOLARPROP is taken into account. We then fit the cosmic-ray proton data provided by AMS-02 and Voyager in the energy range 4 MeVâ30 GeV, and confirm that the modulation time lag in this model is about 9 months, which is consistent with the previous studies. This model incorporates a more realistic description of the polarity reversing and provides a more reliable estimation of the solar modulation effect during the maximum activity period
Analysis of bronchoscopy characteristics for 729 female patients with lung cancer
Background and objective The aim of this article is to study features of the bronchoscopy signs in female lung cancer patients. Methods The bronchoscopy data of 729 female lung cancer patients enrolled between January 1994 and June 2007 was analyzed, retrospectively. Results Most of the patients were middle-aged female (57.0%), then were the elderly (28.5%), and the youth composed much lower (14.0%). The most common histopathology was adenocarcinoma (42.8%), followed by squamous cell carcinoma (23.9%) and small cell carcinoma (19.2%), and all of them increased in the past few years. The female lung cancers were more in the right lung (P<0.05), and the upper lobes (P<0.05). Among 729 female lung cancer patients, 92.0% had apparent signs. Most of adenocarcinoma had infiltrative changes (P<0.05), but most of squamous cell carcinoma and small cell carcinoma had proliferative changes (P<0.05). The most common sing of bronchoscopy in patients with atelectasis was proliferative changes (P<0.05), but the most common sings of bronchoscopy in patients with pleural effusion was infiltrative changes (P<0.05). Conclusion This study suggests brochoscopy is an important approach in diagnosis of female lung cancer. Paying more attention to the lung cancer of female patients and examining with bronchoscopy would be helpful for earlier diagnosis
Flame-Retarded Rigid Polyurethane Foam Composites with the Incorporation of Steel Slag/Dimelamine Pyrophosphate System: A New Strategy for Utilizing Metallurgical Solid Waste
Rigid polyurethane (RPUF) was widely used in external wall insulation materials due to its good thermal insulation performance. In this study, a series of RPUF and RPUF-R composites were prepared using steel slag (SS) and dimelamine pyrophosphate (DMPY) as flame retardants. The RPUF composites were characterized by thermogravimetric (TG), limiting oxygen index (LOI), cone calorimetry (CCT), and thermogravimetric infrared coupling (TG-FTIR). The results showed that the LOI of the RPUF-R composites with DMPY/SS loading all reached the combustible material level (22.0 vol%~27.0 vol%) and passed UL-94 V0. RPUF-3 with DMPY/SS system loading exhibited the lowest pHRR and THR values of 134.9 kW/m2 and 16.16 MJ/m2, which were 54.5% and 42.7% lower than those of unmodified RPUF, respectively. Additionally, PO· and PO2· free radicals produced by pyrolysis of DMPY could capture high energy free radicals, such as H·, O·, and OH·, produced by degradation of RPUF matrix, effectively blocking the free radical chain reaction of composite materials. The metal oxides in SS reacted with the polymetaphosphoric acid produced by the pyrolysis of DMPY in combustion. It covered the surface of the carbon layer, significantly insulating heat and mass transport in the combustion area, endowing RPUF composites with excellent fire performance. This work not only provides a novel strategy for the fabrication of high-performance RPUF composites, but also elucidates a method of utilizing metallurgical solid waste
Design and Nonadiabatic Photoisomerization Dynamics Study of a Three-Stroke Light-Driven Molecular Rotary Motor
Working cycle of conventional light-driven molecular rotary motors (LDMRMs), especially Feringa-type motors, usually have four steps, two photoisomerization steps, and two thermal helix inversion (THI) steps. THI steps hinder the ability of the motor to operate at lower temperatures and limit the rotation speed of LDMRMs. A three-stroke LDMRM, 2-(2,7-dimethyl-2,3-dihydro-1H-inden-1-ylidene)-1,2-dihydro-3H-pyrrol-3-one (DDIY), is proposed, which is capable of completing an unidirectional rotation by two photoisomerization steps and one thermal helix inversion step at room temperature. On the basis of trajectory surface-hopping simulation at the semi-empirical OM2/MRCI level, the EPâZP and ZPâEM nonadiabatic photoisomerization dynamics of DDIY were systematically analyzed. Quantum yields of EPâZP and ZPâEM photoisomerization of DDIY are ca. 34% and 18%, respectively. Both EPâZP and ZPâEM photoisomerization processes occur on an ultrafast time scale (ca. 100â300 fs). This three-stroke LDMRM may stimulate further research for the development of new families of more efficient LDMRMs
Design and Nonadiabatic Photoisomerization Dynamics Study of a Three-Stroke Light-Driven Molecular Rotary Motor
Working cycle of conventional light-driven molecular rotary motors (LDMRMs), especially Feringa-type motors, usually have four steps, two photoisomerization steps, and two thermal helix inversion (THI) steps. THI steps hinder the ability of the motor to operate at lower temperatures and limit the rotation speed of LDMRMs. A three-stroke LDMRM, 2-(2,7-dimethyl-2,3-dihydro-1H-inden-1-ylidene)-1,2-dihydro-3H-pyrrol-3-one (DDIY), is proposed, which is capable of completing an unidirectional rotation by two photoisomerization steps and one thermal helix inversion step at room temperature. On the basis of trajectory surface-hopping simulation at the semi-empirical OM2/MRCI level, the EP→ZP and ZP→EM nonadiabatic photoisomerization dynamics of DDIY were systematically analyzed. Quantum yields of EP→ZP and ZP→EM photoisomerization of DDIY are ca. 34% and 18%, respectively. Both EP→ZP and ZP→EM photoisomerization processes occur on an ultrafast time scale (ca. 100–300 fs). This three-stroke LDMRM may stimulate further research for the development of new families of more efficient LDMRMs
Facile Synthesis of ZincâContaining Mesoporous Silicate from Iron Tailings and Enhanced Fire Retardancy of Rigid Polyurethane Foam
Abstract Iron tailings (ITS), as solid decay absolved afterward beneficiation, are adverse to the environment. ITS to prepare zincâcontaining mesoporous silicate (MAOâZn) by a calcinationâcrystallization method are used. An admixture of ammonium polyphosphate (APP) and MAOâZn can solve the problem of poor flame retardancy in rigid polyurethane foam (RPUF), giving them higher thermal stability and lower heat release. The total heat release rate and smoke factor values exhibited by RPUFâ3 are 24.52Â MJÂ mâ2 and 234.29Â MWÂ mâ2 respectively, a decrease of 38.45% and 29.60% respectively compared to pure RPUF. Lower combustible and toxic gas release intensities are in RPUFâ3. Meanwhile, RPUFâ3 possesses enhanced compactness char residue with higher graphitization degree, endowing RPUFâ3 with excellent fire observed performance. This work demonstrates the potential of ITS in the fire retardancy field