337 research outputs found
Three-Pulse Photon Echo of Finite Numbers of Molecules: Single-Molecule Traces
In conventional bulk nonlinear spectroscopy,
the contribution from
molecules with different environmental conditions sometimes conceals
the properties of interest and prevents the assessment of the heterogeneity
of complex systems. This is especially true when exploring mechanisms
of coherence loss in multicomponent systems [Ishizaki and Fleming, <i>J. Phys. Chem. B</i> <b>2011</b>, <i>115</i>, 6227]. To avoid this drawback of ensemble measurements and evaluate
single-molecule behavior, a quantum theory is proposed to study the
three-pulse photon echo signal of a two-level system in a bath and
reveal the fluctuations inherent to single molecules. The current
method takes advantage of the coherent state representation to understand
the photon echo experiment in a wave function formalism rather than
the reduced density matrix. Information regarding the environmental
degrees of freedom (DoF) is explicitly encoded in the initial state
of the system plus bath. The thermal fluctuations of the initial states
induce variation of the photon echo signal, which is clearly different
from the ensemble average echo signal. We use our formalism to demonstrate
the recovery of the conventional ensemble response signal from the
single-molecule signal
Inhomogeneous Broadening Induced Long-Lived Integrated Two-Color Coherence Photon Echo Signal
Recent
observations of the long-lasting nonlinear signals in a
variety of light-harvesting complexes have initiated an active debate
on the origin of long-lived coherence in the biological systems. In
this work we show that disorder of site energy can induce a long-lived
electronic coherence between two chromophores in a strongly coupled
dimer system, in addition to the ensemble dephasing effect. This phenomenon
is physically explained as the correlated fluctuation of excitons
with the equal delocalization on two sites, when the site-energy distributions
overlap to give resonance. Using the integrated two-color coherence
photon echo signal as an example, we show that the coherence in such
a system exhibits a biexponential decay with a slow component with
a lifetime of hundreds of femtoseconds and a rapid component with
a lifetime of tens of femtoseconds. The current result provides a
possible microscopic basis for the electronic coherence to be the
origin of the long-lived coherence signals to be considered along
with other recently proposed mechanisms
Electron Presolvation in Tetrahydrofuran-Incorporated Supramolecular Sodium Entities
Alkali metal atoms can repopulate their valence electrons
toward
solvation due to impact from solvents or microsurroundings and provide
the remaining alkali metal cations for coordinating with a variety
of specific solvents, forming various electron-expanded complexes
or solvated ionic pairs with special interactions. Such special solute–solvent
interactions not only affect their electronic structures but also
enable the formation of entirely new species. Taking Na(THF)n (n = 1–6,
THF = tetrahydrofuran) and Na2@THF complexes as typical
representatives, density functional theory calculations are carried
out to explore the solvation of a sodium atom and its dimer in THF
and characterize their complexes as solvent-incorporated supramolecular
entities and particularly valence electron presolvation due to their
interaction with solvent THF. Electron presolvation is caused by the
Pauli repulsion between THF containing a coordinating O atom with
a lone pair of electrons and the alkali metal Na or Na2 containing valence electrons, and THF coordination to them forces
their valence electrons to redistribute, which can be easily realized
in such solvents. Compared with strongly bound valance electrons of
alkali metal atoms, THF coordination enables Na or Na2 electrons
to exhibit much more active states (i.e., the presolvated states)
featuring small vertical detachment energies of electrons and distorted
diffuse distributions in the frames of the generally structured metal
cation complexes, acting as the electron-expanded chemical entities.
Furthermore, the degree of electron diffusion and the polarity of
the Na–Na bond are proportional to the coordination number
(n) and the coordination number difference (Δn) between two Na centers in Na2@THF. The unique
properties of such entities are also discussed. This work offers a
theoretical support to the supramolecular entities formed by alkali-metal
atoms or their dimers with ligands containing O or N and uncovers
the unique electron presolvation phenomena and also enriches our understanding
of the novel metal atom complexes
Frequency-resolved photon-electronic spectroscopy for excited state population detection
Atomic excitation to excited states in strong laser field is the key to high-order harmonic generation below ionization threshold, yet remains unclear mainly due to the lack of proper detection methods. We propose a frequency-resolved photon-electron spectroscopy technique to reconstruct population of excited states with the second delayed laser pulse. The technique utilizes Fourier transformation to separate ionization from different excited states to different positions on the spectrum. With the advantage of separation, we provide a scheme to reconstruct populations on different excited states after the first pulse. The scheme is validated by high-precision population reconstruction of helium and hydrogen atoms
Table_3_Expression and prognosis analysis of PAQR5 in kidney cancer.docx
Progestin and adipoQ receptor 5 (PAQR5) affects the development of various malignancies and is specifically expressed in kidney. However, the role of PAQR5 in renal carcinoma remains unclear. We assessed the state of PAQR5 expression in kidney renal clear cell carcinoma (KIRC) by The Cancer Genome Atlas and Gene Expression Omnibus datasets. Moreover, immunohistochemistry was performed to observe the expressions of PAQR5 protein in tumor tissues. The relationships between PAQR5 expression and clinical characteristics were investigated by UALCAN. Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan–Meier plotter were used to analyze the effect of PAQR5 expression levels on overall survival and relapse-free survival (RFS). The re lationships between clinical characteristics and survival were also evaluated by univariate and multifactorial Cox regression. Gene Ontology term analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed on PAQR5 to explain the enrichment pathways and functions. Protein and protein interactions were explained by GeneMANIA and STRING. We also explored the relevance of PAQR5 to tumor immune cell infiltration and immunomodulatory molecules by TIMER and GEPIA. Finally, we explored the correlation of PAQR5 with the pathway proteins STATs, HIF-1α, and mTOR using the GSE40435 dataset. PAQR5 expression was low in KIRC and correlated significantly with clinical characteristics including cancer stage, tumor grade, and nodal metastasis status. Low PAQR5 expression was significantly associated with poorer survival. Cox regression analysis indicated that upregulation of PAQR5 was an independent factor for a good prognosis of KIRC. PAQR5 downregulation was associated mainly with STAT3 target upregulation, tumorigenesis, and poor differentiation. PAQR5 expression also correlated positively with B cells, neutrophils, macrophages, and dendritic cells and negatively with the infiltration of FOXP3+ Treg cells and the immune checkpoint molecules PD-1, CTLA4, and LAG3. Moreover, PAQR5 expression in KIRC was negatively correlated with the pathway proteins STAT1/2/3/4/5A, HIF-1α, and mTOR. PAQR5 is an excellent predictor of KIRC prognosis and may be a potential molecular therapeutic target.</p
Table_4_Expression and prognosis analysis of PAQR5 in kidney cancer.docx
Progestin and adipoQ receptor 5 (PAQR5) affects the development of various malignancies and is specifically expressed in kidney. However, the role of PAQR5 in renal carcinoma remains unclear. We assessed the state of PAQR5 expression in kidney renal clear cell carcinoma (KIRC) by The Cancer Genome Atlas and Gene Expression Omnibus datasets. Moreover, immunohistochemistry was performed to observe the expressions of PAQR5 protein in tumor tissues. The relationships between PAQR5 expression and clinical characteristics were investigated by UALCAN. Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan–Meier plotter were used to analyze the effect of PAQR5 expression levels on overall survival and relapse-free survival (RFS). The re lationships between clinical characteristics and survival were also evaluated by univariate and multifactorial Cox regression. Gene Ontology term analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed on PAQR5 to explain the enrichment pathways and functions. Protein and protein interactions were explained by GeneMANIA and STRING. We also explored the relevance of PAQR5 to tumor immune cell infiltration and immunomodulatory molecules by TIMER and GEPIA. Finally, we explored the correlation of PAQR5 with the pathway proteins STATs, HIF-1α, and mTOR using the GSE40435 dataset. PAQR5 expression was low in KIRC and correlated significantly with clinical characteristics including cancer stage, tumor grade, and nodal metastasis status. Low PAQR5 expression was significantly associated with poorer survival. Cox regression analysis indicated that upregulation of PAQR5 was an independent factor for a good prognosis of KIRC. PAQR5 downregulation was associated mainly with STAT3 target upregulation, tumorigenesis, and poor differentiation. PAQR5 expression also correlated positively with B cells, neutrophils, macrophages, and dendritic cells and negatively with the infiltration of FOXP3+ Treg cells and the immune checkpoint molecules PD-1, CTLA4, and LAG3. Moreover, PAQR5 expression in KIRC was negatively correlated with the pathway proteins STAT1/2/3/4/5A, HIF-1α, and mTOR. PAQR5 is an excellent predictor of KIRC prognosis and may be a potential molecular therapeutic target.</p
Table_5_Expression and prognosis analysis of PAQR5 in kidney cancer.docx
Progestin and adipoQ receptor 5 (PAQR5) affects the development of various malignancies and is specifically expressed in kidney. However, the role of PAQR5 in renal carcinoma remains unclear. We assessed the state of PAQR5 expression in kidney renal clear cell carcinoma (KIRC) by The Cancer Genome Atlas and Gene Expression Omnibus datasets. Moreover, immunohistochemistry was performed to observe the expressions of PAQR5 protein in tumor tissues. The relationships between PAQR5 expression and clinical characteristics were investigated by UALCAN. Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan–Meier plotter were used to analyze the effect of PAQR5 expression levels on overall survival and relapse-free survival (RFS). The re lationships between clinical characteristics and survival were also evaluated by univariate and multifactorial Cox regression. Gene Ontology term analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed on PAQR5 to explain the enrichment pathways and functions. Protein and protein interactions were explained by GeneMANIA and STRING. We also explored the relevance of PAQR5 to tumor immune cell infiltration and immunomodulatory molecules by TIMER and GEPIA. Finally, we explored the correlation of PAQR5 with the pathway proteins STATs, HIF-1α, and mTOR using the GSE40435 dataset. PAQR5 expression was low in KIRC and correlated significantly with clinical characteristics including cancer stage, tumor grade, and nodal metastasis status. Low PAQR5 expression was significantly associated with poorer survival. Cox regression analysis indicated that upregulation of PAQR5 was an independent factor for a good prognosis of KIRC. PAQR5 downregulation was associated mainly with STAT3 target upregulation, tumorigenesis, and poor differentiation. PAQR5 expression also correlated positively with B cells, neutrophils, macrophages, and dendritic cells and negatively with the infiltration of FOXP3+ Treg cells and the immune checkpoint molecules PD-1, CTLA4, and LAG3. Moreover, PAQR5 expression in KIRC was negatively correlated with the pathway proteins STAT1/2/3/4/5A, HIF-1α, and mTOR. PAQR5 is an excellent predictor of KIRC prognosis and may be a potential molecular therapeutic target.</p
Structural Reconstruction of Optically Invisible State in a Single Molecule via Scanning Tunneling Microscope
Molecular
dark states, participating in various energy- and electron-transfer
processes, are typically beyond direct optical-spectroscopic measurements
because of the forbidden transition dictated by the selection rule.
In this work, we demonstrate a direct profile of the dark-state transition
density of a single molecule on the subnanometer scale by using a
scanning tunneling microscope. Our method allows one to resolve the
four-lobe configuration in a 1 nm region for the example molecule.
The current proposal will bring about a new methodology to study the
single-molecule properties in electro-optical devices and light-assisted
biological processes
Table_1_Expression and prognosis analysis of PAQR5 in kidney cancer.docx
Progestin and adipoQ receptor 5 (PAQR5) affects the development of various malignancies and is specifically expressed in kidney. However, the role of PAQR5 in renal carcinoma remains unclear. We assessed the state of PAQR5 expression in kidney renal clear cell carcinoma (KIRC) by The Cancer Genome Atlas and Gene Expression Omnibus datasets. Moreover, immunohistochemistry was performed to observe the expressions of PAQR5 protein in tumor tissues. The relationships between PAQR5 expression and clinical characteristics were investigated by UALCAN. Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan–Meier plotter were used to analyze the effect of PAQR5 expression levels on overall survival and relapse-free survival (RFS). The re lationships between clinical characteristics and survival were also evaluated by univariate and multifactorial Cox regression. Gene Ontology term analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed on PAQR5 to explain the enrichment pathways and functions. Protein and protein interactions were explained by GeneMANIA and STRING. We also explored the relevance of PAQR5 to tumor immune cell infiltration and immunomodulatory molecules by TIMER and GEPIA. Finally, we explored the correlation of PAQR5 with the pathway proteins STATs, HIF-1α, and mTOR using the GSE40435 dataset. PAQR5 expression was low in KIRC and correlated significantly with clinical characteristics including cancer stage, tumor grade, and nodal metastasis status. Low PAQR5 expression was significantly associated with poorer survival. Cox regression analysis indicated that upregulation of PAQR5 was an independent factor for a good prognosis of KIRC. PAQR5 downregulation was associated mainly with STAT3 target upregulation, tumorigenesis, and poor differentiation. PAQR5 expression also correlated positively with B cells, neutrophils, macrophages, and dendritic cells and negatively with the infiltration of FOXP3+ Treg cells and the immune checkpoint molecules PD-1, CTLA4, and LAG3. Moreover, PAQR5 expression in KIRC was negatively correlated with the pathway proteins STAT1/2/3/4/5A, HIF-1α, and mTOR. PAQR5 is an excellent predictor of KIRC prognosis and may be a potential molecular therapeutic target.</p
Exergy Analysis and Modeling of Pilot-Scale Pyrolysis for Magnesium Oxide Preparation from Salt Lake Bischofite Industrial Waste
Currently, the traditional
magnesium oxide production process is
facing exceptional challenges arising from carbon emission restrictions
and environmental protection. Waste bischofite pyrolysis has attracted
much attention as a promising technology to address these challenges.
Nonetheless, this process has primarily been demonstrated on a laboratory
scale, with limited studies on an industrial scale. A comprehensive
exergy analysis was conducted for the entire process and individual
subunits within the pyrolysis process to identify potential areas
for process enhancement. A FORTRAN subroutine based on empirical correlations
of pyrolysis product yields was developed considering the impact of
decomposition reactions on the simulation. Furthermore, the optimization
of energy and exergy efficiency of the system was discussed in terms
of the carbon dioxide emission factor, equivalence ratio, and pyrolysis
temperature. The results show that the primary energy bottleneck lies
in the combustion phase. In addition, the optimal energy and exergy
efficiency conditions are a carbon dioxide emission factor of 5.3,
an equivalent ratio of 1.15, and a pyrolysis temperature of 1100 °C.
In comparison to the pilot-scale conditions, the energy efficiency
and exergy efficiency increase by 2.55 and 3.61%, respectively. At
this time, the MgO yield is 100%, and the HCl concentration is above
9.33%
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