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We measured equilibrium constants for H3O+(H2O)n-1 + H2O ↔ H3O+(H2O)n (n = 4-9) reactions taking place in an ion drift tube with various applied electric fields at gas temperatures of 238-330 K. The zero-field reaction equilibrium constants were determined by extrapolation of those obtained at non-zero electric fields. From the zero-field reaction equilibrium constants, the standard enthalpy and entropy changes, ΔH0n,n-1 and ΔS0n,n-1, of stepwise association for n = 4-8 were derived and were in reasonable agreement with those measured in previous studies. We also examined the electric field dependence of the reaction equilibrium constants at non-zero electric fields for n = 4-8. An effective temperature for the reaction equilibrium constants at non-zero electric field was empirically obtained using a parameter describing the electric field dependence of the reaction equilibrium constants. Furthermore, the size dependence of the parameter was thought to reflect the evolution of the hydrogen-bond structure of H3O+(H2O)n with the cluster size. The reflection of structural information in the electric field dependence of the reaction equilibria is particularly noteworthy. [ABSTRACT FROM AUTHOR]

Background To describe a case with dislodgement of dental bridge with clasps covering the vocal cords, in a patient who was successfully intubated using tube exchanger under video-assisted laryngoscopy. Study design, methods Clinical case record with a video clip. Setting University hospital. Case presentation A 83-year-old woman presented with dislodgement of her dental bridge whilst eating. Laryngoscopy revealed a foreign body almost entirely covering the vocal cords, with the clasps of the dislodged partial denture piercing the pharyngeal wall. Before induction of general anesthesia, a tracheal tube introducer combined with video-assisted laryngoscopy was introduced into the trachea in the awake condition, followed by successful endotracheal intubation. Thereafter, the dislodged denture was extracted via the oral cavity. Conclusions Tracheal tube introducers combined with video-assisted laryngoscopy appear to be useful for airway management, decreasing the number of avoidable tracheostomies performed. [ABSTRACT FROM AUTHOR]

Objective: The object was to describe 2 novel cases of peritonsillar abscess showing peculiar extension to the masticator space. Methods: The methods included clinical case records, including computed tomography and surgical approaches. Results: Both patients we encountered were suffering from systematic diseases, with case 1 involving a 75-year-old man with diabetes mellitus and case 2 involving a 90-year-old woman taking immunosuppressive medications. The abscesses were peritonsillar in origin, extending primarily to the parapharyngeal space, with unusual secondary extension to the masticator space. Extraoral drainage conducted in case 1 was useful for assessing the masticator space and surrounding spaces, but endoscopy-assisted intraoral drainage in case 2 was less invasive, obviating the need for identifying the facial nerve. Conclusions: It is important to bear in mind that patients suffering from systemic diseases may display unusual extension of deep head and neck infections, and enhanced computed tomography is a useful modality for evaluating such extensions. [ABSTRACT FROM AUTHOR]

Isolated frontal sinusitis with mixed bacterial colonies is extremely rare and has not been described. We report a case of isolated frontal sinus forming mixed bacterial colonies that occurred in the previously exposed frontal sinus. The material in the frontal sinus was macroscopically similar to sinus fungus ball. Surgical strategy followed that for sinus fungus ball. The material could not be completely removed even with an endoscopic modified Lothrop procedure (Draf type III procedure). Additional external incision enabled complete removal of the remnant infectious substance. Histological examination detected two different types of organisms as intermingled bacterial colonies. External approaches to the frontal fungus ball have recently been replaced by the endonasal approach. Our case suggests that material trapped in a pit or small crevice in a frontal sinus may not be removed intranasally. [ABSTRACT FROM AUTHOR]

Nasopalatine duct cysts are the most common non-odontogenic cysts in the maxilla, and are conventionally treated through a sublabial or palatine approach. Recently, the endoscopic approach has been used, but experience is extremely limited. We treated a 29-year-old male with nasopalatine duct cyst by endoscopic marsupialization, but paresthesia of the incisor region occurred after surgery. This paresthesia gradually remitted within 6 months. The nasopalatine nerve, which innervates the upper incisor region, enters two lateral canals separately at the nasal floor and exits the central main canal at the palate. Damage to the bilateral nasopalatine nerves might lead to paresthesia, so we recommend careful examination for nerve fibers during endoscopic surgery, especially if fenestration is performed on both sides. [ABSTRACT FROM AUTHOR]

Howardite–eucrite–diogenite meteorites are believed to originate in the crust of the asteroid 4 Vesta, whose differentiation processes are still controversial. In this study, the first 176Lu–176Hf isotopic data of nine diogenites are presented together with their 87Rb–87Sr isotopic compositions and rare earth element (REE) abundances to investigate the differentiation process of diogenites. The 176Lu–176Hf data sets of nine diogenites revealed the significantly higher initial 176Hf/177Hf ratio of diogenites than that of eucrites, while there are no resolvable differences between their ages. Based on the high initial ratio and the early formation of diogenites, their source material is estimated to be the Vestan mantle. The 87Rb–87Sr systematics of nine diogenites are entirely disturbed probably due to impact events on Vesta. The significant variation observed in the REE abundances of nine diogenites suggests their crystallization from compositionally diverse melts. Based on the mantle origin and compositional diversity of diogenites, we propose the crystallization of diogenites from partial melts of the Vestan mantle. The variation of the trace element abundances of diogenites can be explained by the variation of the degree of the partial melting. The timescale between the crystallization and partial melting of the Vestan mantle is estimated to be ∼100–600 Ma from the 176Lu–176Hf isotopic data of nine diogenites, while a heat source for the partial melting is uncertain. [ABSTRACT FROM AUTHOR]

Aqueous alteration is one of the primitive activities that occurred on meteorite parent bodies in the early solar system. The Tagish Lake meteorite is known to show an intense parent body aqueous alteration signature. In this study, quantitative analyses of the alkaline elements and isotopic analyses of Sr and Ba from acid leachates of TL (C2-ungrouped) were performed to investigate effects of aqueous alteration. The main purpose of this study is to search for isotopic evidence of extinct 135Cs from the Ba isotopic analyses in the chemical separates from the Tagish Lake meteorite. Barium isotopic data from the leachates show variable 135Ba isotopic anomalies (ε = −2.6 ∼ +3.6) which correlatewith 137Ba and 138Ba suggesting a heterogeneous distribution of s- and r-rich nucleosynthetic components in the early solar system. The 87Rb–87Sr and 135Cs–135Ba decay systems on TL in this study do not provide any chronological information. The disturbance of the TL chronometers is likely a reflection of the selective dissolution of Cs and Rb given the relatively higher mobility of Cs and Rb compared to Ba and Sr, respectively, during fluid mineral interactions. [ABSTRACT FROM AUTHOR]

We quantitatively investigated the hydrogen addition reactions of acetylene (C2H2) and ethylene (C2H4) on amorphous solid water (ASW) at 10 and 20 K relevant to the formation of ethane (C2H6) on interstellar icy grains. We found that the ASW surface enhances the reaction rates for C2H2 and C2H4 by approximately a factor of 2 compared to those on the pure-solid C2H2 and C2H4 at 10 K, probably due to an increase in the sticking coefficient and adsorption energy of the H atoms on ASW. In contrast to the previous proposal that the hydrogenation rate of C2H4 is orders of magnitude larger than that of C2H2, the present results show that the difference in hydrogenation rates of C2H2 and C2H4 is only within a factor of 3 on both the surfaces of pure solids and ASW. In addition, we found the small kinetic isotope effect for hydrogenation/deuteration of C2H2 and C2H4 at 10 K, despite the requirement of quantum tunneling. At 20 K, the reaction rate of deuteration becomes even larger than that of hydrogenation. These unusual isotope effects might originate from a slightly larger number density of D atoms than H atoms on ASW at 20 K. The hydrogenation of C2H2 is four times faster than CO hydrogenation and can produce C2H6 efficiently through C2H4 even in the environment of a dark molecular cloud. [ABSTRACT FROM AUTHOR]

It is known that the Sayama meteorite (CM2) shows an extensive signature for aqueous alteration on the meteorite parent body, and that most of the primary minerals in the chondrules are replaced with phyllosilicates as the result of the aqueous alteration. In this paper, it is confirmed from the observation of two-dimensional Raman spectra that a part of olivine in a chondrule collected from the Sayama chondrite is serperntinized. Ion microprobe analysis of the chondrule showed that alkaline elements such as Rb and Cs are heterogeneously redistributed in the chondrule. The result of higher Rb and Cs contents in serpentinized phases in the chondrule rather than in other parts suggested the selective adsorption of alkaline elements into the serpentine in association with early aqueous activity on the meteorite parent body. Furthermore Ba isotopic analysis provided variations of 135Ba/138Ba and 137Ba/138Ba in the chondrule. This result was consistent with our previous isotopic data suggesting isotopic evidence for the existence of the presently extinct nuclide 135Cs in the Sayama meteorite, but the abundance of 135Cs in the solar system remains unclear because of large analytical uncertainties. [ABSTRACT FROM AUTHOR]