Efficient reduction of CCl took place upon exposure to 350-nm photons of aqueous solutions containing sulfonated poly(ether etherketone) (SPEEK) as a sensitizer and either poly(vinyl alcohol) (PVA) or HCOH/HCO buffer. The photoreaction formed chloride ions whose concentration increased linearly with time in solutions free of O, whereas slower reductions occurred in the presence of air. Utilization of formate buffer as the H-atom donor yielded photoreactions at least 10 times faster than those in the presence of PVA and generated CHCl as another reaction product. The quantum yield of chloride ion formation, ø(Cl), was found to be a function of both the SPEEK concentration and concentration of formate buffer. Whereas the quantum efficiency increased steadily with decreasing solution acidity, a drastic surge in the reaction rate occurred in neutral solutions. ø(Cl) first increased rapidly to a maximum value exceeding 1 at pH 7.3 and then decreased thereafter. The dependence of r(Cl) on (I), where I is the light intensity, and the occurrence of postirradiation formation of Cl through the reduction of CCl in the dark are further evidence that the photoreaction proceeded by a chain process. Several of the kinetic features were rationalized by means of a mechanism involving the α-hydroxy radicals of SPEEK and •CCl as chain carriers.

Mitochondria, the power house of the cell, are one of the most dynamic cell organelles. Although there are several reports on actin- or microtubule-dependent movement of mitochondria in plant cells, intracellular positioning and motility of mitochondria under different light conditions remain open questions. Mitochondria were visualized in living Arabidopsis thaliana leaf cells using green fluorescent protein fused to a mitochondrion-targeting signal. In darkness, mitochondria were distributed randomly in palisade cells. In contrast, mitochondria accumulated along the periclinal walls, similar to the accumulation response of chloroplasts, when treated with weak blue light (470 nm, 4 micromol m(-2) s(-1)). Under strong blue light (100 micromol m(-2) s(-1)), mitochondria occupied the anticlinal positions similar to the avoidance response of chloroplasts and nuclei. While strong red light (660 nm, 100 micromol m(-2) s(-1)) induced the accumulation of mitochondria along the inner periclinal walls, green light exhibited little effect on the distribution of mitochondria. In addition, the mode of movement of individual mitochondria along the outer periclinal walls under different light conditions was precisely analyzed by time-lapse fluorescence microscopy. A gradual increase in the number of static mitochondria located in the vicinity of chloroplasts with a time period of blue light illumination clearly demonstrated the accumulation response of mitochondria. Light-induced co-localization of mitochondria with chloroplasts strongly suggested their mutual metabolic interactions. This is the first characterization of the light-dependent redistribution of mitochondria in plant cells.

Dominant mutations in PIEZO2, which codes for the principal mechanotransduction channel for proprioception and touch sensation, have been found to cause different forms of distal arthrogryposis. Some observations suggest that these dominant mutations induce a gain-of-function effect on the channel. Here, we report a consanguineous family with three siblings who showed short stature, scoliosis, gross motor impairment, and a progressive form of contractures involving the distal joints that is distinct from that found in patients with dominant mutations in PIEZO2. These siblings also displayed deficits in proprioception and touch sensation. Whole-exome sequencing performed in the three affected siblings revealed the presence of a rare homozygous variant (c.2708C>G; p.S903*) in PIEZO2. This variant is predicted to disrupt PIEZO2 function by abolishing the pore domain. Sanger sequencing confirmed that all three siblings are homozygous whereas their parents and an unaffected sibling are heterozygous for this variant. Recessive mutations in PIEZO2 thus appear to cause a progressive phenotype that overlaps with, while being mostly distinct from that associated with dominant mutations in the same gene.

The crystallization of fluoro-silicate glasses obtained using high-purity SiO2, AlO1.5, CdF2, PbF2, ZnF2, and ErF3 has been investigated. Upon heat treatment, PbF2 nanocrystals form which host most of the Er3+ ions. The major peaks obtained by x-ray diffraction suggest that the nanocrystals are fluorite structured, but the low volume fraction of nanocrystals and line broadening due to their small size mean that unambiguous identification of the crystal structure is impossible. Therefore, atomistic simulation techniques have been performed to investigate the mechanism of incorporation of Er3+ in the PbF2 nanocrystals and polycrystalline (1−x)PbF2–xErF3 ceramics have been fabricated to study the expected phase assemblage.