11 research outputs found
Dependence of Real Refractive Indices on O:C, H:C and Mass Fragments of Secondary Organic Aerosol Generated from Ozonolysis and Photooxidation of Limonene and α-Pinene
<div><p>The refractive index is a fundamental property controlling aerosol optical properties. Secondary organic aerosols have variable refractive indices, presumably reflecting variations in their chemical composition. Here, we investigate the real refractive indices (m<sub>r</sub>) and chemical composition of secondary organic aerosols (SOA) generated from the oxidation of α-pinene and limonene with ozone and NO<sub>x</sub>/sunlight at different HC/NO<sub>x</sub> ratios. Refractive indices were retrieved from polar nephelometer measurements using parallel and perpendicular polarized 532-nm light. Particle chemical composition was monitored with a high-resolution time-of-flight aerosol mass spectrometer (HR-Tof-AMS). For photochemically generated SOA, the values of refractive indices are consistent with prior results, and ranged from about 1.34 to 1.55 for limonene and from 1.44 to 1.47 for α-pinene, generally increasing as the particles grew. While AMS fragments are strongly correlated to the refractive index for each type of SOA, the relationships are in most cases quite different for different SOA types. Consistent with its wide range of refractive index, limonene SOA shows larger variations compared to α-pinene SOA for most parameters measured with the AMS, including H:C, O:C, f<sub>43</sub> (<i>m/z</i> 43/organic), f<sub>C4H7</sub><sup>+</sup>, and others. Refractive indices for α-pinene ozonolysis SOA also fell in narrow ranges; 1.43–1.45 and 1.46–1.53 for particles generated at 19–22 and 23–29°C, respectively, with corresponding small changes of f<sub>43</sub> and H:C ratio and other parameters. Overall, H:C ratio, m/z 43 and 55 (C<sub>2</sub>H<sub>3</sub>O<sup>+</sup>, C<sub>4</sub>H<sub>7</sub><sup>+</sup>) were the best correlated with refractive index for all aerosol types investigated. The relationships between m<sub>r</sub> and most fragments support the notion that increasing condensation of less oxygenated semivolatile species (with a possible role for a concomitant decrease in low refractive index water) is responsible for the increasing m<sub>r</sub>s observed as the experiments progress. However, the possibility that oligomerization reactions play a role cannot be ruled out.</p>
</div
Geological resources of scandium: a review from a Chinese perspective
Scandium (Sc) is a dispersed metal in Earth’s lithosphere, with an average abundance of 16 to 22 ppm. In the meantime, it is widely considered as a critical metal because of its paramount significance in scientific research and technical innovation. With surging demands that are not backed-up by current supplies globally, the market price of Sc oxide is astonishingly five times more than the most expensive rare earth oxide of terbium (Tb). Production of Sc is significantly held back due to scarcity of economically viable grades at explorable depths within the crust, compared with other critical metals such as REE, Nb and Ta. Nevertheless, typical high- to intermediate-grade Sc deposits, as compiled in this review, consistently show close relationships to specific magmatic (e.g. ultramafic-mafic and carbonatitic), supergene and hydrothermal processes during Sc enrichment, especially the former two. Known potential Sc deposits are tentatively classified based on their host rocks and metallogeny, including those hosted in the ultramafic-mafic rocks and related laterites, in carbonatite and related laterites, in bauxite residue and processed coals, hydrothermal Sc deposits and Sc deposits related to syenite intrusions, pegmatites or marine sediments. We also discuss the Sc enrichment mechanism and associated tectonics and partition coefficients of Sc among diverse minerals and melts, which reveal the preference of Sc for clinopyroxene, garnet and iron oxides by isomorphic replacement or ion absorption during diverse magmatic and supergene Sc enrichment processes. Lastly, Sc resources in the world-class Bayan Obo deposit are discussed in detail as an illustrative benchmark example, where hydrothermal aegirine may host majority of carbonatite-derived Sc.</p
Melanin-Inspired Composite Materials: From Nanoarchitectonics to Applications
Synthetic
melanin is a mimic of natural melanin analogue
with intriguing
properties such as metal–ion chelation, redox activity, adhesion,
and broadband absorption. Melanin-inspired composite materials are
formulated by assembly of melanin with other types of inorganic and
organic components to target, combine, and build up the functionality,
far beyond their natural capabilities. Developing efficient and universal
methodologies to prepare melanin-based composite materials with unique
functionality is vital for their further applications. In this review,
we summarize three types of synthetic approaches, predoping, surface
engineering, and physical blending, to access various melanin-inspired
composite materials with distinctive structure and properties. The
applications of melanin-inspired composite materials in free radical
scavenging, bioimaging, antifouling, and catalytic applications are
also reviewed. This review also concludes current challenges that
must be addressed and research opportunities in future studies
Efficient Directional Excitation of Surface Plasmons by a Single-Element Nanoantenna
Directional light scattering is important
in basic research and real applications. This area has been successfully
downscaled to wavelength and subwavelength scales with the development
of optical antennas, especially single-element nanoantennas. Here,
by adding an auxiliary resonant structure to a single-element plasmonic
nanoantenna, we show that the highly efficient lowest-order antenna
mode can be effectively transferred into inactive higher-order modes.
On the basis of this mode conversion, scattered optical fields can
be well manipulated by utilizing the interference between different
antenna modes. Both broadband directional excitation of surface plasmon
polaritons (SPPs) and inversion of SPP launching direction at different
wavelengths are experimentally demonstrated as typical examples. The
proposed strategy based on mode conversion and mode interference provides
new opportunities for the design of nanoscale optical devices, especially
directional nanoantennas
DataSheet_1_Lung adenocarcinoma: selection of surgical approaches in solid adenocarcinoma from the viewpoint of clinicopathologic features and tumor microenvironmental heterogeneity.docx
IntroductionSolid adenocarcinoma represents a notably aggressive subtype of lung adenocarcinoma. Amidst the prevailing inclination towards conservative surgical interventions for diminutive lung cancer lesions, the critical evaluation of this subtype’s malignancy and heterogeneity stands as imperative for the formulation of surgical approaches and the prognostication of long-term patient survival.MethodsA retrospective dataset, encompassing 2406 instances of non-solid adenocarcinoma (comprising lepidic, acinar, and papillary adenocarcinoma) and 326 instances of solid adenocarcinoma, was analyzed to ascertain the risk factors concomitant with diverse histological variants of lung adenocarcinoma. Concurrently, RNA-sequencing data delineating explicit pathological subtypes were extracted from 261 cases in the TCGA database and 188 cases in the OncoSG database. This data served to illuminate the heterogeneity across lung adenocarcinoma (LUAD) specimens characterized by differential histological features.ResultsSolid adenocarcinoma is associated with an elevated incidence of pleural invasion, microscopic vessel invasion, and lymph node metastasis, relative to other subtypes of lung adenocarcinoma. Furthermore, the tumor microenvironment (TME) in solid pattern adenocarcinoma displayed suboptimal oxygenation and acidic conditions, concomitant with augmented tumor cell proliferation and invasion capacities. Energy and metabolic activities were significantly upregulated in tumor cells of the solid pattern subtype. This subtype manifested robust immune tolerance and capabilities for immune evasion.ConclusionThis present investigation identifies multiple potential metrics for evaluating the invasive propensity, metastatic likelihood, and immune resistance of solid pattern adenocarcinoma. These insights may prove instrumental in devising surgical interventions that are tailored to patients diagnosed with disparate histological subtypes of LUAD, thereby offering valuable directional guidance.</p
DataSheet_2_Lung adenocarcinoma: selection of surgical approaches in solid adenocarcinoma from the viewpoint of clinicopathologic features and tumor microenvironmental heterogeneity.xlsx
IntroductionSolid adenocarcinoma represents a notably aggressive subtype of lung adenocarcinoma. Amidst the prevailing inclination towards conservative surgical interventions for diminutive lung cancer lesions, the critical evaluation of this subtype’s malignancy and heterogeneity stands as imperative for the formulation of surgical approaches and the prognostication of long-term patient survival.MethodsA retrospective dataset, encompassing 2406 instances of non-solid adenocarcinoma (comprising lepidic, acinar, and papillary adenocarcinoma) and 326 instances of solid adenocarcinoma, was analyzed to ascertain the risk factors concomitant with diverse histological variants of lung adenocarcinoma. Concurrently, RNA-sequencing data delineating explicit pathological subtypes were extracted from 261 cases in the TCGA database and 188 cases in the OncoSG database. This data served to illuminate the heterogeneity across lung adenocarcinoma (LUAD) specimens characterized by differential histological features.ResultsSolid adenocarcinoma is associated with an elevated incidence of pleural invasion, microscopic vessel invasion, and lymph node metastasis, relative to other subtypes of lung adenocarcinoma. Furthermore, the tumor microenvironment (TME) in solid pattern adenocarcinoma displayed suboptimal oxygenation and acidic conditions, concomitant with augmented tumor cell proliferation and invasion capacities. Energy and metabolic activities were significantly upregulated in tumor cells of the solid pattern subtype. This subtype manifested robust immune tolerance and capabilities for immune evasion.ConclusionThis present investigation identifies multiple potential metrics for evaluating the invasive propensity, metastatic likelihood, and immune resistance of solid pattern adenocarcinoma. These insights may prove instrumental in devising surgical interventions that are tailored to patients diagnosed with disparate histological subtypes of LUAD, thereby offering valuable directional guidance.</p
Specifically Formed Corona on Silica Nanoparticles Enhances Transforming Growth Factor β1 Activity in Triggering Lung Fibrosis
A corona is a layer
of macromolecules formed on a nanoparticle
surface <i>in vivo</i>. It can substantially change the
biological identity of nanomaterials and possibly trigger adverse
responses from the body tissues. Dissecting the role of the corona
in the development of a particular disease may provide profound insights
for understanding toxicity of nanomaterials in general. In our present
study, we explored the capability of different silica nanoparticles
(SiNPs) to induce silicosis in the mouse lung and analyzed the composition
of coronas formed on these particles. We found that SiNPs of certain
size and surface chemistry could specifically recruit transforming
growth factor β1 (TGF-β1) into their corona, which subsequently
induces the development of lung fibrosis. Once embedded into the corona
on SiNPs, TGF-β1 was remarkably more stable than in its free
form, and its fibrosis-triggering activity was significantly prolonged.
Our study meaningfully demonstrates that a specific corona component
on a certain nanoparticle could initiate a particular pathogenic process
in a clinically relevant disease model. Our findings may shed light
on the understanding of molecular mechanisms of human health risks
correlated with exposure to small-scale substances
Specifically Formed Corona on Silica Nanoparticles Enhances Transforming Growth Factor β1 Activity in Triggering Lung Fibrosis
A corona is a layer
of macromolecules formed on a nanoparticle
surface <i>in vivo</i>. It can substantially change the
biological identity of nanomaterials and possibly trigger adverse
responses from the body tissues. Dissecting the role of the corona
in the development of a particular disease may provide profound insights
for understanding toxicity of nanomaterials in general. In our present
study, we explored the capability of different silica nanoparticles
(SiNPs) to induce silicosis in the mouse lung and analyzed the composition
of coronas formed on these particles. We found that SiNPs of certain
size and surface chemistry could specifically recruit transforming
growth factor β1 (TGF-β1) into their corona, which subsequently
induces the development of lung fibrosis. Once embedded into the corona
on SiNPs, TGF-β1 was remarkably more stable than in its free
form, and its fibrosis-triggering activity was significantly prolonged.
Our study meaningfully demonstrates that a specific corona component
on a certain nanoparticle could initiate a particular pathogenic process
in a clinically relevant disease model. Our findings may shed light
on the understanding of molecular mechanisms of human health risks
correlated with exposure to small-scale substances
Light Absorption Properties and Radiative Effects of Primary Organic Aerosol Emissions
Organic aerosols (OAs) in the atmosphere
affect Earth’s
energy budget by not only scattering but also absorbing solar radiation
due to the presence of the so-called “brown carbon”
(BrC) component. However, the absorptivities of OAs are not represented
or are poorly represented in current climate and chemical transport
models. In this study, we provide a method to constrain the BrC absorptivity
at the emission inventory level using recent laboratory and field
observations. We review available measurements of the light-absorbing
primary OA (POA), and quantify the wavelength-dependent imaginary
refractive indices (<i>k</i><sub>OA</sub>, the fundamental
optical parameter determining the particle’s absorptivity)
and their uncertainties for the bulk POA emitted from biomass/biofuel,
lignite, propane, and oil combustion sources. In particular, we parametrize
the <i>k</i><sub>OA</sub> of biomass/biofuel combustion
sources as a function of the black carbon (BC)-to-OA ratio, indicating
that the absorptive properties of POA depend strongly on burning conditions.
The derived fuel-type-based <i>k</i><sub>OA</sub> profiles
are incorporated into a global carbonaceous aerosol emission inventory,
and the integrated <i>k</i><sub>OA</sub> values of sectoral
and total POA emissions are presented. Results of a simple radiative
transfer model show that the POA absorptivity warms the atmosphere
significantly and leads to ∼27% reduction in the amount of
the net global average POA cooling compared to results from the nonabsorbing
assumption