Regulation of membrane homeostasis by TMC1 mechanoelectrical transduction channels is essential for hearing

The mechanoelectrical transduction (MET) channel complex of auditory hair cells converts sound into electrical signals, allowing us to hear. After decades of research, the transmembrane-like channel 1 and 2 (TMC1 and TMC2) have been recently identified as pore-forming subunits of the MET channels, but the molecular peculiarity that differentiates these two proteins and makes TMC1 essential for hearing remains elusive. Here, we show that TMC1, but not TMC2, is essential for membrane remodeling triggered by a decrease in intracellular calcium concentration. We demonstrate that inhibition of MET channels or buffering of intracellular calcium lead to pronounced phosphatidylserine externalization, membrane blebbing and ectosome release at the hair cell sensory organelle, culminating in the loss of TMC1 protein. Moreover, three TMC1 deafness-causing mutations cause constitutive phosphatidylserine externalization that correlates with the deafness phenotype, suggesting that the mechanisms of hearing loss involve alterations in membrane homeostasis.

Electro-Optical Properties of Sputtered Calcium Lead Titanate Thin Films for Pyroelectric Detection

We report the deposition and characterization of calcium lead titanate (PCT) thin films for pyroelectric detectors. PCT films of thicknesses ranging from ~250 to 400 nm were deposited on both silicon and Si/SiN/Ti/Au substrates at 13 mTorr pressure by 200W radio frequency sputtering in an Ar + O2 environment. Substrates were kept at variable temperatures during the deposition. The PCT films were annealed at various temperatures in an O2 environment for 15 min. X-ray diffraction results confirm the polycrystalline nature of these films. Energy dispersive spectroscopy function of scanning electron microscope showed that the films are stoichiometric (Ca0.43Pb0.57) TiO3 (Ca/Ti = 0.5, Pb/Ti = 0.66). Temperature dependence of capacitance, pyroelectric current, and pyroelectric coefficient was investigated for different PCT films. Our results show that films deposited at 550 °C and 600 °C demonstrate better quality and larger values of the pyroelectric coefficient. On the other hand, the capacitance fabricated on the PCT films at 550 °C showed the highest value of pyroelectric current and pyroelectric coefficient which were 14 pA and at 30 °C was ~2 µC/m2K respectively at a higher temperature. In addition, we used density functional theory to determine the atomic and band structure, real and imaginary parts of dielectric constant and refractive index, and absorption and reflection constants with energy.

Comparative Characteristics of Free-Machining Steels of Cr-Mo Type

The work investigates the properties of lead-free free-machining steel grade A30KhMAR, containing BN inclusions, in comparison with the base Cr-Mo steel 30KhM, lead-bearing AS30KhM, lead-calcium-bearing ASTs30KhM, calcium-bearing ATs30KhM, bismuth-calcium-bearing AVTs30KhM and tin-bearing AО30KhM. Effect of bismuth, calcium, lead, tin and boron nitride inclusions on steel susceptibility to temper brittleness and cold brittleness is studied. Contamination of steels with non-metallic inclusions is estimated. End-quench hardenability curves of the test steel A30KhMAR are obtained. Free-machining Cr-Mo structural steel, containing low-melting elements, has ASTM grain size of the number of 7–8. Hardenability and austenite grain size are satisfactory compared to the base steel 30KhM. Mechanical properties of the test steel in longitudinal direction (ultimate and proof stress, specific elongation, reduction in area, impact toughness, hardness) were also determined. It was found that bismuth, calcium, lead, tin, boron and nitrogen (in the form of boron nitride inclusions) within the studied limits do not have negative effect on mechanical properties of heat-treated ASTs30KhM, ATs30KhM, AVTs30KhM, A30KhMAR and AО30KhM steels, and the values of strength, plasticity and toughness characteristics satisfy the requirements of GOST standards for the base steel 30KhM and lead-bearing steel AS30KhM.

W sprawie wytwórczości szklarskiej w celtyckim oppidum w Starym Hradisku na Morawach

Discussion presented in the article is based upon analysis of glass fragments from the late La Tene oppidum. Existence of the jewellery manufacture workshop in Stare Hradisko, producing bracelets and possibly also beads of dark-blue, dark-yellow and green glass of external origin, is speculated based upon chemical composition of 5 fragments as well as morphological analysis. Further complex studies are postulated, which will facilitate unequivocal testing of the speculation about existence of glass works in StareHradisko. Analysed samples revealed presence of the soda-calcium-aluminium-silicon as well as the soda-calcium-lead-aluminium-silicon glass.