Summary
Biomineralization of the extracellular matrix is an essential, regulated process. Inappropriate mineralization of bone and the vasculature has devastating effects on patient health, yet an integrated understanding of the chemical and cell biological processes that lead to mineral nucleation remains elusive. Here, we report that biomineralization of bone and the vasculature is associated with extracellular poly(ADP-ribose) synthesized by poly(ADP-ribose) polymerases in response to oxidative and/or DNA damage. We use ultrastructural methods to show poly(ADP-ribose) can form both calcified spherical particles, reminiscent of those found in vascular calcification, and biomimetically calcified collagen fibrils similar to bone. Importantly, inhibition of poly(ADP-ribose) biosynthesis
in vitro
and
in vivo
inhibits biomineralization, suggesting a therapeutic route for the treatment of vascular calcifications. We conclude that poly(ADP-ribose) plays a central chemical role in both pathological and physiological extracellular matrix calcification.
The development of better Li-ion battery (LIB) electrodes
requires
an orchestrated effort to improve the active materials as well as
the electron and ion transport in the electrode. In this paper, iron
silicide is studied as an anode material for LIBs because of its higher
conductivity and lower volume expansion compared to pure Si particles.
In addition, carbon nanotubes (CNTs) can be synthesized from the surface
of iron-silicides using a continuous flow coating process where precursors
are first spray dried into micrometer-scale secondary particles and
are then flown through a chemical vapor deposition (CVD) reactor.
Some CNTs are formed inside the secondary particles, which are important
for short-range electrical transport and good utilization of the active
material. Surface-bound CNTs on the secondary particles may help establish
a long-range conductivity. We also observed that these spherical secondary
particles allow for better electrode coating quality, cyclability,
and rate performance than unstructured materials with the same composition.
The developed electrodes retain a gravimetric capacity of 1150 mAh/g
over 300 cycles at 1A/g as well as a 43% capacity retention at a rate
of 5 C. Further, blended electrodes with graphite delivered a 539
mAh/g with high electrode density (∼1.6 g/cm3) and
areal capacity (∼3.5 mAh/cm2) with stable cycling
performance.
Highly efficient single-cell elemental analysis of microbial cells was achieved using a developed ICP-MS system with approximately 100% cell introduction efficiency and high time resolution.
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Trace elemental analysis of single yeast cells with time-resolved inductively coupled plasma mass spectrometry (ICP-MS) was successfully carried out, where a high efficiency cell introduction system (HECIS) consisting of the high performance concentric nebulizer (HPCN) and a low-volume (15 mL) on-axis spray chamber utilizing a sheath gas flow were used. Cell adsorption to the flow injector and sample tubing was reduced with the addition of a simple 4.3 mmol L -1 of NaCl solution to the cell suspension and cell flowing liquid, allowing consecutive measurements without fear of significant contamination from previous measurements. Initially using a quadrupole mass analyzer ICP-MS (ICP-QMS) at its lowest integration time (10 ms), current spikes corresponding to separate cell events were detected for several elements (Mg, P, Ca, Mn, Fe, Cu, and Zn) on the introduction of the cell suspension. On comparing the number of peaks in the spectrum for phosphorous with the cell count using a haemocytometer, a reproducible cell transport efficiency of 75.0 ± 4.7% was achieved. Preliminary experiments into using time of flight ICP-MS (ICP-TOFMS) for single-cell analysis were carried out, allowing quasi-simultaneous multielement detection. The spectra of Mg, P, Ca, Mn, Fe, Cu, and Zn, with a time resolution of 1 ms were simultaneously obtained in one measurement. A relatively strong correlation was observed for the spectra between P and Zn (correlation factor 0.69), P and Mg (0.63), and Mg and Zn (0.63). These results indicate that the time resolved quasi-simultaneous multielement measurement may be useful for the correlation analysis of multielements in cells.
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