A
bstract
Flavor SU(3) symmetry is a powerful tool to analyze charmed baryon decays. In this work, we propose an approach to generate SU(3) sum rules for the singly and doubly charmed baryon decays ...without writing the Wigner-Eckhart invariants explicitly. The SU(3) sum rules are computed routinely in several master formulas. Hundreds of SU(3) sum rules are found to serve as test of the flavor symmetry in the charmed baryon decays.
A
bstract
Isospin symmetry is the most precise flavor symmetry. In this work, we propose an approach to generate isospin sum rules for heavy hadron decays without the Wigner-Eckhart invariants. The ...effective Hamiltonian of heavy quark weak decay is fully invariant under a series of isospin lowering operators
I
−
n
and then the isospin sum rules can be generated through several master formulas. It provides a systematic way to study the isospin symmetry of
c
- and
b
-hadron weak decays. The theoretical framework of this approach is presented in detail with the nonleptonic decays of
D
and
B
mesons as examples. In addition, the
V
-/
U
-spin sum rules are derived in a similar algorithm by replacing
I
−
n
with
V
−
n
/
U
−
n
.
With the proliferation of photo-editing applications on smartphones, selfie editing has become more and more popular. Despite its popularity, only a few studies have examined the predictors of this ...behavior. Using a young Chinese sample, this study examined whether narcissism, extraversion, body-esteem (includes BE-appearance, BE-attribution, and BE-weight) and social comparison orientation (SCO) can predict selfie-editing frequency on social networking sites (SNSs). Hierarchical regression analysis showed that narcissism, extraversion, BE-attribution and SCO were positively related to selfie-editing frequency while BE-appearance was negatively related to selfie-editing frequency.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A
bstract
We proposed a theoretical framework to correlate the topological diagram at quark level and rescattering dynamics at hadron level. In the framework, both the hadronic triangle diagram, and ...the topological-scattering diagram, which is the intermediate structure between topological diagram and triangle diagram, are expressed in the tensor form. The completeness of topological-scattering diagram is confirmed by the quark substructure of meson-meson scattering. The coefficient of each triangle diagram can be derived from the topological-scattering diagram and the total rescattering amplitudes are consistent with the ones derived from the chiral Lagrangian. If only the short-distance
T
diagram is considered as the weak vertex in triangle diagram, the rescattering contributions in the
C
,
E
and
P
diagrams have definite proportional relation of
L
(
C
) :
L
(
E
) :
L
(
P
) =
−
2 : 1 : 1 under the
SU
(3)
F
symmetry, and the rescattering contributions in the
T
and
A
diagrams only arise from the
SU
(3)
F
breaking effects. Taking
D
→
Kπ
and
D
→
ππ
modes as examples, we present our framework in detail. We find the Isospin relations in these decays are still valid in terms of triangle diagrams. Besides, the conclusions in the
D
meson decays under the
SU
(3)
F
symmetry can be generalized to the
B
meson decays under the
SU
(4)
F
symmetry.
High demand for green ecosystems has urged the human community to reconsider and revamp the traditional way of synthesis of several compounds. Ammonia (NH3) is one such compound whose applications ...have been extended from fertilizers to explosives and is still being synthesized using the high energy inhaling Haber‐Bosch process. Carbon free electrocatalytic nitrogen reduction reaction (NRR) is considered as a potential replacement for the Haber‐Bosch method. However, it has few limitations such as low N2 adsorption, selectivity (competitive HER reactions), low yield rate etc. Since it is at the early stage, tremendous efforts have been devoted in understanding the reaction mechanism and screening of the electrocatalysts and electrolytes. In this review, the electrocatalysts are classified based on the periodic table with heat maps of Faraday efficiency and yield rate of NH3 in NRR and their electrocatalytic properties toward NRR are discussed. Also, the activity of each element is discussed and short tables and concise graphs are provided to enable the researchers to understand recent progress on each element. At the end, a perspective is provided on countering the current challenges in NRR. This review may act as handbook for basic NRR understandings, recent progress in NRR, and the design and development of advanced electrocatalysts and systems.
This review focuses on electrocatalytic properties of periodic elements toward the nitrogen reduction reaction. Recent advancements and working mechanisms of various elements are illustrated with appropriate tables and graphs. Overall, this review intends to open different directions for the fabrication of high efficiency electrocatalysts.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A powerful technique to detect bone biomarkers has been developed for assessment of osteoporosis at the early stage. Two-dimensional multilayered gold-nanoparticle thin film (MTF-AuNPs) was ...demonstrated as a promising test platform for detection of bone biomarker, hydroxyproline (HYP), measured by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). With strong surface plasmon resonance and excellent homogeneity, facilely prepared, highly ordered, and large-scale MTF-AuNPs revealed high sensitivity of HYP in the SALDI-MS measurement without additional matrixes, such as α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB). Furthermore, the mass spectrum of HYP with MTF-AuNPs was significantly improved in signal intensity enhancement, background noise reduction, and signal-to-noise ratio amplification. The excellent reproducibility of HYP spectra with only 9.3% relative signal variation could be attributed to MTF-AuNPs’ high absorbance at a wavelength of 337 nm, low heat capacity, superior thermal conductivity, and outstanding homogeneity. The calibration curve showed high linear correlation between mass spectrum intensity and HYP concentration in the range of 1 to 100 μM, covering the whole level in healthy people and osteoporosis patients. In particular, the serum sample was directly deposited onto the MTF-AuNP sample substrate without any pretreatment and its HYP concentration was then successfully determined. We believe that the combination of SALDI-MS and MTF-AuNP sample substrates would be a potential approach for bone biomarker detection in the osteoporosis risk assessment.
Graphical abstract
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
High gravimetric energy density, earth-abundance, and environmental friendliness of hydrogen sources have inspired the utilization of hydrogen fuel as a clean alternative to fossil fuels. Hydrogen ...evolution reaction （HER）, a half reaction of water splitting, is crucial to the low-cost production of pure H2 fuels but necessitates the use of electrocatalysts to expedite reaction kinetics. Owing to the availability of low-cost oxygen evolution reaction （OER） catalysts for the counter electrode in alkaline media and the lack of low-cost OER catalysts in acidic media, researchers have focused on developing HER catalysts in alkaline media with high activity and stability. Nickel is well-known as an HER catalyst and continuous efforts have been undertaken to improve Ni-based catalysts as alkaline electrolyzers： In this review, we summarize earlier studies of HER activity and mechanism on Ni surfaces, along with recent progress in the optimization of the Ni-based catalysts using various modern techniques. Recently developed Ni-based HER catalysts are categorized according to their chemical nature, and the advantages as well as limitations of each category are discussed. Among all Ni-based catalysts, Ni-based alloys and Ni-based hetero-structure exhibit the most promising electrocatalytic activity and stability owing to the fine-tuning of their surface adsorption properties via a synergistic nearby element or domain. Finally, selected applications of the developed Ni-based HER catalysts are highlighted, such as water splitting, the chloralkali process, and microbial electrolysis cell.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Background
High incidence of asymptomatic venous thromboembolism (VTE) has been observed in severe COVID‐19 patients, but the characteristics of symptomatic VTE in general COVID‐19 patients have not ...been described.
Objectives
To comprehensively explore the prevalence and reliable risk prediction for VTE in COVID‐19 patients.
Methods/Results
This retrospective study enrolled all COVID‐19 patients with a subsequent VTE in 16 centers in China from January 1 to March 31, 2020. A total of 2779 patients were confirmed with COVID‐19. In comparison to 23,434 non‐COVID‐19 medical inpatients, the odds ratios (ORs) for developing symptomatic VTE in severe and non‐severe hospitalized COVID‐19 patients were 5.94 (95% confidence interval CI 3.91–10.09) and 2.79 (95% CI 1.43–5.60), respectively. When 104 VTE cases and 208 non‐VTE cases were compared, pulmonary embolism cases had a higher rate for in‐hospital death (OR 6.74, 95% CI 2.18–20.81). VTE developed at a median of 21 days (interquartile range 13.25–31) since onset. Independent factors for VTE were advancing age, cancer, longer interval from symptom onset to admission, lower fibrinogen and higher D‐dimer on admission, and D‐dimer increment (DI) ≥1.5‐fold; of these, DI ≥1.5‐fold had the most significant association (OR 14.18, 95% CI 6.25–32.18, p = 2.23 × 10−10). A novel model consisting of three simple coagulation variables (fibrinogen and D‐dimer levels on admission, and DI ≥1.5‐fold) showed good prediction for symptomatic VTE (area under the curve 0.865, 95% CI 0.822–0.907, sensitivity 0.930, specificity 0.710).
Conclusions
There is an excess risk of VTE in hospitalized COVID‐19 patients. This novel model can aid early identification of patients who are at high risk for VTE.
Full text
Available for:
FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Electroencephalography (EEG) measures the neuronal activities in different brain regions via electrodes. Many existing studies on EEG-based emotion recognition do not fully exploit the topology of ...EEG channels. In this article, we propose a regularized graph neural network (RGNN) for EEG-based emotion recognition. RGNN considers the biological topology among different brain regions to capture both local and global relations among different EEG channels. Specifically, we model the inter-channel relations in EEG signals via an adjacency matrix in a graph neural network where the connection and sparseness of the adjacency matrix are inspired by neuroscience theories of human brain organization. In addition, we propose two regularizers, namely node-wise domain adversarial training (NodeDAT) and emotion-aware distribution learning (EmotionDL), to better handle cross-subject EEG variations and noisy labels, respectively. Extensive experiments on two public datasets, SEED, and SEED-IV, demonstrate the superior performance of our model than state-of-the-art models in most experimental settings. Moreover, ablation studies show that the proposed adjacency matrix and two regularizers contribute consistent and significant gain to the performance of our RGNN model. Finally, investigations on the neuronal activities reveal important brain regions and inter-channel relations for EEG-based emotion recognition.
This work investigates the solution phenomenon, aging behavior and room-temperature mechanical properties of maraging steel manufactured by selective laser melting (SLM). Different heat treatment ...experiments, including solution treatment (ST), direct aging treatment (DAT) and solution + aging treatment (SAT) are designed. Microstructure analysis indicates that ST and SAT will eliminate the cellular and lath structures, but DAT has little effect on these. The content of austenite increases with the addition of DAT temperature and holding time. While austenite is almost undetectable in ST and SAT samples. Meanwhile, both the elongation and toughness of the samples with DAT gain a slight improvement with the temperature increasing. Importantly, DAT yields similar microhardness, tensile strength and impact toughness to SAT, although the resultant microstructures are completely different. The results demonstrate that DAT can achieve the similar mechanical properties to SAT samples. Samples with high mechanical properties (microhardness of 653.93 HV and ultimate strength of 2126.30 MPa) have been obtained by DAT at 520 °C for 6 h as well as solution treatment at 900 °C for 1 h and aging treatment at 520 °C for 6 h. This investigation reveals the evolution regularity of microstructure, microhardness, tensile performance and impact toughness of maraging steel manufactured by SLM after different heat treatments.
Full text
Available for:
IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
