Prolonged Ulcerative Laryngitis

Acute and prolonged laryngitis commonly are diagnosed and treated by primary care physicians. These ailments come to the attention of the otolaryngologist when symptoms are prolonged despite treatment. Since the beginning of 1991, the senior authors (RTS, JRS) have recognized a clinical syndrome defined by prolonged hoarseness, prolonged laryngeal inflammation, and vocal fold ulceration. Patients are frequently young, nonsmokers, and nondrinkers who have had an upper respiratory infection prior to, or associated with, the onset of laryngeal symptomatology. Patients may be affected for up to 1 year despite aggressive medical therapy. This review of 14 patients highlights the features of this previously undescribed entity.     

Photochemistry of benzylallene: ring-closing reactions to form naphthalene

Conformer-specific, vibrationally resolved electronic spectroscopy of benzylallene (4-phenyl-1,2-butadiene) is presented along with a detailed analysis of the products formed via its ultraviolet photoexcitation. Benzylallene is the minor product of the recombination of benzyl and propargyl radicals. The mass-selective resonant two-photon ionization spectrum of benzylallene was recorded under jet-cooled conditions, with its S(0)-S(1) origin at 37,483 cm(-1). UV-UV holeburning spectroscopy was used to show that only one conformer was present in the expansion. Rotational band contour analysis provided rotational constants and transition dipole moment direction consistent with a conformation in which the allene side chain is in the anti position, pointing away from the phenyl ring. The photochemistry of benzylallene was studied in a pump-probe geometry in which photoexcitation occurred by counter-propagating the expansion with a photoexcitation laser. The laser was timed to interact with the gas pulse in a short tube that extended the collisional region of the expansion. The products were cooled during expansion of the gas mixture into vacuum, before being interrogated using mass-selective resonant two-photon ionization. The UV-vis spectra of the photochemical products were compared to literature spectra for identification. Several wavelengths were chosen for photoexcitation, ranging from the S(0)-S(1) origin transition (266.79 nm) to 193 nm. Comparison of the product spectral intensities as a function of photoexcitation wavelength provides information on the wavelength dependence of the product yields. Photoexcitation at 266.79 nm yielded five products (benzyl radical, benzylallenyl radical, 1-phenyl-1,3-butadiene, 1,2-dihydronaphthalene, and naphthalene), with naphthalene and benzylallenyl radicals dominant. At 193 nm, the benzylallenyl radical signal was greatly reduced in intensity, while three additional C(10)H(8) isomeric products were observed. An extensive set of calculations of key stationary points on the ground state C(10)H(10) and C(10)H(9) potential energy surfaces were carried out at the DFT B3LYP/6-311G(d,p) level of theory. Mechanisms for formation of the observed products are proposed based on these potential energy surfaces, constrained by the results of cursory studies of the photochemistry of 1-phenyl-1,3-butadiene and 4-phenyl-1-butyne. A role for tunneling on the excited state surface in the formation of naphthalene is suggested by studies of partially deuterated benzylallene, which blocked naphthalene formation.     

Sectionally Semicomplemented Distributive Nearlattices

A nearlattice S is a meet semilattice together with the property that any two elements possessing a common upper bound have a supremum. Here the authors have introduced the notion of sectionally semicomplemented distributive nearlattices and given several characterizations of them. The skeleton SCon(S) of Con(S), the congruence lattice, consists of all those nearlattice congruences which are the pseudocomplements of members of Con(S). The relationship between skeletal congruences and kernel of skeletal congruences leads to numerous characterizations of sectionally semicomplemented distributive nearlattices and semiboolean algebras. For example we prove, for a distributive nearlattice S with 0, the following conditions are equivalent:

QUANTITATION OF THE PHOTOMUTAGENIC RESPONSE OF Salmonella TO AN EASTERN SHALE OIL AND FLUORESCENT LIGHT

The dose-response relationship for photomutation (i.e. photosensitized mutation) by a shale-derived oil was examined. The Ames' Salmonella typhimurium tester strain TA98 was exposed to several concentrations of an Eastern shale oil and UV-visible radiation from illumination-type fluorescent lamps. Reversion to histidine prototrophy and survival were assayed following various radiation doses. Reciprocity of shale oil concentration and radiation exposure over approximately 10-fold ranges of oil concentrations and radiation doses was observed with revertant numbers per plate, percent survival, and the induced frequency of revertants (revertants per survivor). The relationship between mutation frequency and the product (shale oil concentration times radiation exposure) fit well with either a linear model or a power law model in which the frequency of induced mutations was described by the product dose raised to the 1.26th power. Similar dose-response relationships provide potential criteria for comparing potency of photomutagenic substances, comparisons that may be valuable towards assessing, and perhaps modifying, risks imposed by human exposure to synthetic fuels.     

Polarographic determination of aluminium with alizarin

The polarographic determination of aluminium as its complex with alizarin in the pH range 9.2-10.1, with the cathode ray polarograph, is described. A solvent extraction procedure is used to eliminate interferences from many other metals.     

Three new phases in the K/Cu/Th/S system: KCuThS3, K2Cu2ThS4, and K3Cu3Th2S7

Synthetic exploration of K/Cu/Th/S quaternary phase space has yielded three new compounds: KCuThS3 (I), K2Cu2ThS4 (II), and K3Cu3Th2S7 (III). All three phases are semiconductors with optical band gaps of 2.95, 2.17, and 2.49 eV(I-III). Compound I crystallizes in the orthorhombic space group Cmcm with a = 4.076(1) A, b = 13.864(4) A, and c = 10.541(3) A. Compound II crystallizes in the monoclinic space group C2/m with a = 14.522(1) A, b = 4.026(3) A, and c = 7.566(6) A; beta = 109.949(1) degrees . Compound III crystallizes in orthorhombic space group Pbcn with a = 4.051(2) A, b = 14.023(8) A, and c = 24.633(13) A. The compounds are all layered materials, with each layer composed of threads of edge-sharing ThS6 octahedra bridged by CuS4 tetrahedral threads of varying dimension. The layers are separated by well-ordered potassium ions. The relatively wide range of optical band gaps is attributed to the extent of the CuS4 motifs. As the dimension of the CuS4 chains increases, band gaps decrease in the series. All materials were characterized by single-crystal X-ray diffraction, microprobe chemical analysis, and diffuse reflectance spectroscopy (NIR-UV).     

Triamino-s-triazine triradical trications. An experimental study of triazine as a magnetic coupling unit

[structure: see text] Triamino-s-triazine derivatives 3a, 4, and 5 have been prepared, and their cationic states have been analyzed electrochemically. At 298 K, 3a+ has a limited lifetime in CH2Cl2 solution. However, 4+ and 5+ are long-lived under such conditions, and quartet states of 4(3+) and 5(3+) are observed by ESR spectroscopy. Variable-temperature ESR analysis and NMR shift susceptibility measurements indicate that 5(3+) is a doublet ground state with a populated quartet state.     

Nitrosation and hydrolysis studies of some thiazole-4-acetic esters

Nitrosation of hydrazino substituted thiazole-4-acetates has been shown to occur on the ring, rather than the α-methylene carbon, as previously reported. Thus nitrosation of ethyl 2-isopropylidenehydrazono-, 2-benzylidenehydrazono-, 2-(2-benzoylhydrazino)-, and 2-(2-acetylhydrazino)thiazole-4-acetates yielded the corresponding 2-hydrazino-4-carbethoxymethylidene-4,5-dihydrothiazoline-5-oximes. Basic hydrolysis of the thiazoline-5-oxime esters, followed by decarboxylation gave tautomeric mixtures of the 2-hydrazino-4-methyl-2,5-dihydrothiazoline-5-oxime and 2-hydrazino-4-methyl-5-nitrosothiazol derivatives. These tautomeric mixtures were also prepared by nitrosating the 2-hydrazino-4-methylthiazoles. The α,β-unsaturated acids, 2-isopropylidenehydrazono-, 2-benzylidenehydrazono-, and 2-(2-benzoyl-hydrazino)-4-carboxymethylidene-4,5-dihydrothiazoline, were isolated after basic hydrolysis of the corresponding 2-hydrazinothiazole-4-acetic esters. Dinitrosation of the 2-isopropylidenehydrazono-4-carboxy-methylidene-4,5-dihydrothiazoline, followed by decarboxylation, generated 2-isopropylidenehydrazono-5-nitrosothiazole-4-formyloxime.