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Conclusions: Hydrostatic positive pressure and vasoconstrictor acidified the cochlear fluids, whereas the vasodilator made the fluids alkaline. CBF might play a role in regulating cochlea fluid pH. Objectives: Cochlea fluid pH is highly dependent on the HCO3−/CO2 buffer system. Cochlear blood flow (CBF) supplies O2 and removes CO2. It is speculated that cochlear blood flow changes might affect the balance of the HCO3−/CO2 buffer system in the cochlea. It is known that the elevation of inner ear pressure decreases the CBF, and local application of vasodilating or vasoconstricting agents directly to the cochlea changes the CBF. The purpose of this study was to elucidate the effect of positive hydrostatic inner ear pressure and application of a vasodilator and vasoconstrictor of cochlear vessels on the pH of the endolymph and perilymph. Methods: The authors performed animal physiological experiments on 30 guinea pigs. Hydrostatic positive pressure was infused through a glass capillary tube inserted into the scala tympani of the basal turn. The vasodilator, nitric oxide donor (sodium nitroprusside; SNP), and the vasoconstrictor, bupivacaine, were placed topically onto the round window of the guinea pig cochlea. Endolymph pH (pHe) and endocochlear potential (EP) were monitored by double-barreled ion-selective microelectrodes in the second turn of the guinea pig cochlea. During the topical application study, scala vestibuli perilymph pH (pHv) was also measured simultaneously in the second turn. Results: The application of hydrostatic positive pressure caused a decrease in pHe and EP. Positive perilymphatic pressure caused the endolymph to become acidic pressure-dependently. Application of 3.0% SNP evoked an increase in both the pHe and pHv, following by a gradual recovery to baseline levels. On the other hand, 0.5% bupivacaine caused a decrease in both the pHe and pHv. The EP during topical application showed slight, non-significant changes. [ABSTRACT FROM AUTHOR]

The crystal structure of Al3O3.5C0.5 (Z = 3) has been characterized by X-ray powder diffraction (XRPD), transmission electron microscopy, and electron probe microanalysis. The tide compound is trigonal with space group R3m (centrosymmetric) and hexagonal unit-cell dimensions a = 0.29588(1) nm, c = 2.84080(7) nm, and V = 0.21538(1) nm³. The initial structural model was determined by the charge-flipping method and subsequently refined by the Rietveld method. The final structural model showed the positional disordering of one of the two types of Al sites. The maximum-entropy method-based pattern fitting (MPF) method was used to confirm die validity of the split-atom model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The reliability indices calculated from the MPF were Rwp - 4.03%, S (= Rwp/Rc) = 1.17, Rp = 3.08%, RB = 0.82%, and RF = 0.72%. The crystal was composed of antiphase domains, suggesting the occurrence of the high-low phase transition during the cooling process. The transition would be accompanied by the loss of unit-lattice translation, and hence the disordered structural model determined by XRPD might be of the average structure of the low-temperature phase. [ABSTRACT FROM AUTHOR]

The title compound is synthesized from a mixture of Al, Al2O3, and Al4C3 in a molar ratio of 3:5:2 (carbon crucible, argon, 2223 K, 1 h). [ABSTRACT FROM AUTHOR]

A new 3D metal–organic framework (MOF), in which 2D layers are interlaced to form a 3D architecture, was synthesized by a reaction of Cu(BF4)2 and 1,3-bis(4-pyridyl)propane (bpp) in a water/1-hexanol solvent system, and the crystal structure of the MOF was successfully solved. The MOF is reversibly transformed to a 1D chain MOF, which shows gate adsorption properties. The dynamic transformation gives crystal size reduction resulting in a slight change in CO2 adsorption isotherms. The 1D MOF shows selective adsorption/separation properties on benzene and its analogues with similar sizes and shapes (benzene, toluene, and cyclohexane). [ABSTRACT FROM AUTHOR]

Objectives Sleep studies for diagnosing obstructive sleep apnea (OSA) in children are laborious, expensive, inconvenient, and often not readily available. Out-of-center sleep test (OCST) devices have been studied for diagnosing OSA in adults, but few OCST studies have been done in children. The purpose of this study was to clarify the diagnostic reliability of OCST devices for children. Methods OCSTs using pulse oximetry and in-laboratory polysomnography (PSG) were performed separately in 686 adults and 119 children. For each apnea–hypopnea index (AHI) measured with PSG, accuracy, sensitivity, specificity, positive/negative likelihood ratio (PLR/NLR), and positive/negative predictive value (PPV/NPV) were calculated for several cutoff values of 3% oxygen desaturation index (ODI) measured with OCST and analyzed. Results For definitive diagnosis in adults, the specificity, PLR, and PPV with a cutoff value of OCST-ODI 20/h were 98.3%, 29.26, and 97.4%, respectively, to detect PSG-AHI ≥20/h. Corresponding values with a cutoff value of OCST-ODI 15/h were 99%, 46.19, and 99.6% to detect an AHI ≥5/h. For exclusive diagnosis (screening) in adults, sensitivity, NLR, and NPV with a cutoff value of OCST-ODI 5/h were 96.4%, 0.068, and 91.9% to detect PSG-AHI <20/h and 84.1%, 0.21, and 45.9% to detect PSG-AHI <5/h. or definitive diagnosis in children, the corresponding values with a cutoff value of OCST-ODI 25/h were 98.6%, 16.0, and 90.9% to detect PSG-AHI ≥10/h and 98.1%, 8.281, and 90.9% for PSG-AHI ≥5/h. For exclusive diagnosis in children, with a cutoff of OCST-ODI 10/h, the corresponding values were 62.2%, 0.446, and 78.2% to detect PSG-AHI <10/h, 45.3%, 0.674, and 55.1% for PSG-AHI <5/h, and 34.0%, 0.908, and 10.3% for PSG-AHI <1/h. Statistical data of preschool children tended to be worse than those of school age children. Conclusions In adults, OCST is reliable for the definitive diagnosis of AHI ≥20/h or ≥5/h and the exclusive diagnosis of AHI <20/h. However, in children, OCST should not be used alone for the definitive diagnosis or exclusive diagnosis. [ABSTRACT FROM AUTHOR]

Iodine concentration and radioisotopic composition (129I/I) were measured in the pore waters from the gas hydrate occurrence in the forearc basin offshore Shimokita Peninsula, north-eastern Japan, to determine the source formation of I and accompanying hydrocarbons. Iodine concentrations correlate well with the alkalinity and SO4 patterns, reflecting degradation stages of I-rich buried organic matter, rapidly increasing in the sulfate reduction interval, and becoming constant below 250 meters below the seafloor with an upwelling flux of 1.5 × 10−11 µmol cm−2 year−1. The 129I/I ratios of 300 × 10−15–400 × 10−15 in deep pore waters suggest ages for iodine and hydrocarbon sources as old as 40 Ma. These ages correlate well with the coaly source formations of the Eocene age thought to be responsible for the conventional natural gas deposits underlying the gas hydrate stability zone. Similar profiles are observed in 129I/I ratios of pore waters in the gas hydrate stability zone from the forearc basin in the eastern Nankai Trough, offshore central Japan, where pore waters are enriched in I and reach ages as old as ∼50 Ma through the sediment column. At the outer ridge site along the trough, on the other hand, relatively younger I are more frequently delivered probably through thrusts/faults associated with subduction. The nature of source formations of I and hydrocarbons in the offshore Shimokita Peninsula has a more terrestrial contribution compared with those in the Nankai Trough, but these formations are also considerably older than the host sediments, suggesting long-term transport of I and hydrocarbons for the accumulation of gas hydrates in both locations. [ABSTRACT FROM AUTHOR]