We
used a single particle mass spectrometry to online detect chemical
compositions of individual particles over four seasons in Guangzhou.
Number fractions (Nfs) of all the measured particles that contained
oxalate were 1.9%, 5.2%, 25.1%, and 15.5%, whereas the Nfs of Fe-containing
particles that were internally mixed with oxalate were 8.7%, 23.1%,
45.2%, and 31.2% from spring to winter, respectively. The results
provided the first direct field measurements for the enhanced formation
of oxalate associated with Fe-containing particles. Other oxidized
organic compounds including formate, acetate, methylglyoxal, glyoxylate,
purivate, malonate, and succinate were also detected in the Fe-containing
particles. It is likely that reactive oxidant species (ROS) via Fenton
reactions enhanced the formation of these organic compounds and their
oxidation product oxalate. Gas-particle partitioning of oxalic acid
followed by coordination with Fe might also partly contribute to the
enhanced oxalate. Aerosol water content likely played an important
role in the enhanced oxalate formation when the relative humidity
is >60%. Interactions with Fe drove the diurnal variation of oxalate
in the Fe-containing particles. The study could provide a reference
for model simulation to improve understanding on the formation and
fate of oxalate, and the evolution and climate impacts of particulate
Fe.
Cysteine-rich 61 (CYR61/CCN1), a secreted protein in bone marrow (BM) microenvironment, has diverse effects on many cellular activities such as growth and differentiation. However, the effect of CCN1 on osteoblasts (OBs) in myeloma bone disease remains unclear. In our study, the level of CCN1 in multiple myeloma (MM) patients was detected by ELISA and RT-PCR. The proliferation and differentiation of OBs from MM patients were observed after stimulated by CCN1 in vitro. The myeloma cells transduced with CYR61 gene (RPMI‑8226/CYR61) were injected in a mouse model to evaluate the efficacy of CCN1 in vivo and compare with zoledronic acid. The results showed that CYR61/CCN1 levels in BM supernatant and OBs both elevated significantly in all newly diagnosed MM patients, especially in patients without bone disease (P=0.001 and P<0.001). After 30 ng/l CCN1 stimulation for 24 h, the quantity and mineralization of OBs increased significantly in vitro (P=0.046 and 0.048). The transcription factors of Wnt pathway, runt-related transcription factor 2 (Runx2) and β-catenin were upregulated in OBs after CCN1 stimulation (P=0.012 and 0.011). After injection of RPMI‑8226 cells, bone lesions were observed obviously by microCT and histochemistry at 7 weeks. Radiographic analysis of the bones showed decreased resorption in CCN1 overexpression group and zoledronic acid group, while severe resorption in negative control. Furthermore, trabecular bone volume in CCN1 overexpression group (1.7539±0.16949) was significantly higher than zoledronic acid group (1.2839±0.077) (P=0.012). In conclusion, CCN1 can stimulate the proliferation and differentiation of OBs in vitro and contribute to bone remodeling in vivo in MBD.
While laboratory studies have demonstrated
that aqueous reactions
between carbonyls and reduced nitrogen species may contribute to the
production of N-heterocycle brown carbon (BrC) such as imidazole,
there is currently a lack of evidence for this in the atmosphere.
We investigated the mixing state of carbonyls, ammonium, amines, and
imidazole (as a surrogate of BrC) in cloud residual, interstitial,
and cloud-free particles by single-particle mass spectrometry. The
results provide the first ambient evidence of the formation of imidazole
through reactions between carbonyls and ammonium/amines at the individual
particle level. The key evidence for this is that 60% of the imidazole
particles are internally mixed with carbonyls and ammonium/amines.
The number fraction of imidazole is significantly enhanced in particles
with internally mixed carbonyls and ammonium (7.8%)/amines (26.7%),
compared with that (1.4%) in all of the cloud-free particles. Furthermore,
a higher number fraction of imidazole is observed in all cloud residual
and interstitial particles (2.9%) than in the cloud-free particles
(1.4%). This is due to the enhancement of amines and/or the synergistic
effect of ammonium and amines in the formation of imidazole in cloud
residual and interstitial particles. These findings extend the current
understanding of the formation and evolution of imidazole-based BrC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.