Effervescent agents in acute esophageal food impaction.

Acute esophageal food impaction (AEFI) occurs frequently. Few data are published describing the use of effervescent agents (EAs) for treatment of AEFI. We aimed to evaluate the effectiveness, cost, and safety of EAs in the treatment of AEFI. We retrospectively identified patients aged 18 years and older who were seen in the emergency department of 2 hospitals in 1 metropolitan area from January 1, 2011, through April 4, 2016, who had a clinical diagnosis of AEFI. We collected and analyzed data on outcomes and cost associated with the use of EAs, glucagon, and no pharmacologic therapy. During the study period, 239 patients with AEFI met the inclusion criteria. Of the 45 patients who received EA monotherapy, 25 (55.6%) responded successfully, compared with 11 of 62 (17.7%) who received glucagon monotherapy (P < .001) and 16 of 93 (17.2%) who had no therapy (P < .001). Ten of 39 patients (25.6%) who were given both glucagon and EA responded successfully. The other 177 patients had endoscopy, which was successful in all cases. Median hospitalization charges for patients who responded successfully to EA alone were $1,136, compared with $2,602 for responders to glucagon alone (P < .001) and $1,194 for those who cleared their bolus spontaneously (P < .001). All patients who received EA monotherapy had lower median hospitalization costs ($2,384) than all patients who received glucagon monotherapy ($9,289; P = .03) and all patients who received neither ($8,386; P = .02). Effervescent agents are a safe, effective, and cost-saving initial strategy in the treatment of acute esophageal food impaction.

Adverse respiratory effects following overhaul in firefighters.

Overhaul is the stage in which firefighters search for and extinguish possible sources of reignition. It is common practice not to wear respiratory protection during overhaul. Fifty-one firefighters in two groups, 25 without respiratory protection and 26 wearing cartridge respirators, were monitored for exposure to products of combustion and changes in spirometric measurements and lung permeability following overhaul of a structural fire. Testing at baseline and 1 hour after overhaul included forced vital capacity (FVC), forced expiratory volume in one second (FEV1), serum Clara cell protein (CC16), and serum surfactant-associated protein A (SP-A). Overhaul increased CC16 in both groups, indicating increased alveolarcapillary membrane permeability. Contrary to expectations, SP-A increased and FVC and FEV1 decreased in the firefighters wearing cartridge respirators. Changes in FEV1, CC16, and SP-A were associated with concentrations of specific products of combustion or carboxyhemoglobin levels. Firefighter exposures during overhaul have the potential to cause changes in spirometric measurements and lung permeability, and self-contained breathing apparatus should be worn during overhaul to prevent lung injury.

Characterization of firefighter exposures during fire overhaul.

Previous studies have characterized firefighter exposures during fire suppression. However, minimal information is available regarding firefighter exposures during overhaul, when firefighters look for hidden fire inside attics, ceilings, and walls, often without respiratory protection. A comprehensive air monitoring study was conducted to characterize City of Phoenix firefighter exposures during the overhaul phase of 25 structure fires. Personal samples were collected for aldehydes; benzene; toluene; ethyl benzene; xylene; hydrochloric acid; polynuclear aromatic hydrocarbons (PNA); respirable dust; and hydrogen cyanide (HCN). Gas analyzers were employed to continuously monitor carbon monoxide (CO), HCN, nitrogen dioxide (NO2), and sulfur dioxide (SO2). Area samples were collected for asbestos, metals (Cd, Cr, Pb), and total dust. During overhaul the following exceeded published ceiling values: acrolein (American Conference of Governmental Industrial Hygienists [ACGIH] 0.1 ppm) at 1 fire; CO (National Institute for Occupational Safety and Health [NIOSH] 200 ppm) at 5 fires; formaldehyde (NIOSH 0.1 ppm) at 22 fires; and glutaraldehyde (ACGIH 0.05 ppm) at 5 fires. In addition, the following exceeded published short-term exposure limit values: benzene (NIOSH 1 ppm) at two fires, NO2 (NIOSH 1 ppm) at two fires, and SO2 (ACGIH 5 ppm) at five fires. On an additive effects basis, PNA concentrations exceeded the NIOSH recommended exposure limits (0.1 mg/M3) for coal tar pitch volatiles at two fires. Maximum concentrations of other sampled substances were below their respective permissible exposure limits. Initial 10-min average CO concentrations did not predict concentrations of other products of combustion. The results indicate that firefighters should use respiratory protection during overhaul. In addition, these findings suggest that CO should not be used as an indicator gas for other contaminants found in this atmosphere.

The structure of ferritin cores determined by electron nanodiffraction.

Electron nanodiffraction, with a 100-keV electron beam less than 1 nm in diameter, has been used to obtain single-crystal diffraction patterns from individual iron-containing cores of ferritin molecules. We show that, while a majority of the cores have a hexagonal structure somewhat similar to the major phase in the mineral ferrihydrite, as previously assumed, several minor phases are present including some that are similar in structure to the iron oxides magnetite and hematite and also some composed of highly disordered material. In general, each core consists of one single crystal of one phase.

C-H...O interactions in dimethyl 6,6'-dimethoxy-3,3',5,5'-tetramethylbiphenyl-2,2'-dicarboxylate.

The title compound, C22H26O6, crystallized in the centrosymmetric space group Pbcn with half of the molecule as the asymmetric unit (the molecular symmetry is 2). The H atoms of each of the four methyl groups in the asymmetric unit are disordered over two sites. Nine leading C-H...O interactions are present, with H...O distances ranging from 2.50 to 2.87 A and C...O distances ranging from 3.157 (3) to 3.567 (3) A. The various interaction chains from a three-dimensional network. The intramolecular angle between the biphenyl ring planes (twist angle) is 71.3 (1) degree.

Hydrogen bonding and C-H...X interactions in two triclinic phases of 4-carboxyquinolinium chloride monohydrate.

The title substance, C10H8NO2+.Cl-.H2O, crystallized in the centrosymmetric space group P1 in two phases, alpha and beta, each with one organic cation, one Cl- ion and one water molecule in the asymmetric unit. The principle structural difference in the two asymmetric units lies in the relative orientation of the water molecule. Three hydrogen bonds in the alpha phase have donor-acceptor distances (N...Cl or O...Cl) ranging from 3.052 (1) to 3.189 (2) A, while one has an O...O distance of 2.603 (3) A. Three hydrogen bonds in the beta phase have donor-acceptor distances (N...Cl or O...Cl) ranging from 3.044 (2) to 3.206 (2) A, while two have O...O distances of 2.586 (2) and 3.147 (3) A. The H atoms in all these hydrogen bonds are ordered. Each of these phases has five leading C-H...X interactions, for which the H...X distances are less than, or at most slightly greater than, the corresponding van der Waals radius sums. Taken together, these hydrogen bonds and C-H...X interactions form a three-dimensional network of interactions in each phase. The dihedral angle between the best-fit quinoline core plane and the carboxyl group plane is 25.9 (1) degree for the alpha phase and 20.0 (1) degree for the beta phase.

Hydrogen bonding and C-H...O interactions in bis(8-dimethylamino-1-dimethylammonionaphthalene) [(DMANH+)2] 4,8-dicarboxynaphthalene-1,5-dicarboxylate dihydrate.

The title substance, 2C14H19N2+.C14H6O8(2-).2H2O, crystallized in the centrosymmetric space group P1 with one monopositive dimethylamine-dimethylammonio cation, half of a dinegative acid anion and one water molecule in the asymmetric unit, with the anion located on a center of symmetry. There are four intermolecular hydrogen bonds, of which three have Odonor...Oacceptor distances of 2.577 (1), 2.946 (2) and 2.764 (2) A, while the fourth has an Ndonor...Oacceptor distance of 3.154 (2) A. There is a single intramolecular hydrogen bond, in which the Ndonor...Nacceptor distance is 2.620 (2) A. In each case, the O, or N, and H atoms are ordered. The Ndonor-H distance in the intramolecular hydrogen bond, 1.06 (1) A, is among the shortest seen in this cation at room temperature. Moreover, the antiplanar orientation of the H atom in the hydrogen bond between acid anions is noteworthy. There are, in addition, 12 significant intermolecular C-H...O interactions. In these, the C...O distances range from 3.229 (2)-3.671 (2) A, while the C-H...O angles range from 121-165 degrees for the fixed H atoms involved. A three-dimensional network of hydrogen-bonding interactions is generated.

2-(Isopropylthio)benzoic acid.

The title acid, C10H12O2S, crystallized in the centrosymmetric space group P2(1)/c with one molecule in the asymmetric unit. There is a single hydrogen bond, in which the O and H atoms are ordered and OD...OA is 2.658(2) A. The hydrogen bond forms a cyclic dimer, with graph-set descriptor R2(2)(8), about a center of symmetry. The dihedral angle between the best-fit planes of the benzene ring and the carboxyl group is 13.6(1) degrees.

Hydrogen bonding in quinolinium-4-carboxylate trihydrate.

The previously undescribed title substance, C10H7NO2.-3H2O, crystallized in the centrosymmetric space group P1 with one zwitterionic organic molecule and three water molecules in the asymmetric unit. One N-H...O and six O-H...O hydrogen bonds are present in this structure, with donor-acceptor distances ranging from 2.607(2) to 2.931(3) A. The H atoms in these hydrogen bonds are ordered. The hydrogen bonds generate a two-dimensional network. Structural comparisons are made with quinolinium-4-carboxylate dihydrate.

Hydrogen bonding and C-H...O interactions in 2,2'-dihydroxy-5,5'-dimethoxybiphenyl-3,3'-dicarbaldehyde.

The title dialdehyde, C16H14O6, crystallized in the centrosymmetric space group P1 with one molecule in the asymmetric unit. In this structure, one intermolecular and two intramolecular hydrogen bonds occur; the OD...OA distances are 3.030(2), 2.626(2) and 2.662(2) A. In addition, ten significant C-H...O interactions have C...O distances ranging from 3.342(2) to 3.741(3) A and C-H...O angles ranging from 117 to 167 degrees. The 11 intermolecular interactions link a molecule directly to eight neighbors and form a richly three-dimensional network. The dihedral angle between the best-fit planes of the benzene rings within a molecule (biphenyl twist angle) is 79.00(8) degrees. The dihedral angles between the carboxaldehyde-group planes and the best-fit planes of the rings to which they are attached are 4.7(10) and 2.6(10) degrees.

Dipotassium naphthalene-1,8-dicarboxylate-potassium bicarbonate.

The title substance, tripotassium naphthalene-1,8-dicarboxylate bicarbonate, 3K+.C12H6O4(2-).HCO3-, crystallized in the centrosymmetric space group Pbca. There is a single hydrogen bond. In it, the O and H atoms are ordered and OD...OA is 2.651 (3) A. There is a single significant intermolecular C-H...O interaction, with C...OA = 3.480 (5) A. Each potassium ion is coordinated by an irregular polyhedron of O atoms. These three polyhedra contain eight, eight and five members; each O atom is a member of at least two polyhedra. Structural comparisons are made with tetrapotassium naphthalene-1,4,5,8-tetracarboxylate hexahydrate.

Hydrogen bonding in quinolinium-4-carboxylate dihydrate.

The title acid, C10H7NO2.2H2O, crystallized in the non-centrosymmetric space group Cc with one zwitterionic organic molecule and two water molecules in the asymmetric unit. One N-H...O and four O-H...O hydrogen bonds are present in this structure, with donor-acceptor distances ranging from 2.688 (2) to 2.852 (3) A. These hydrogen bonds generate a three-dimensional network. Structural comparisons are made with anhydrous quinoline-4-carboxylic acid.

Network of C-H...O interactions in 1,2-naphthalenedicarboxylic anhydride.

The title substance, C12H6O3, crystallized in the centrosymmetric space group P2(1)/c with one molecule in the asymmetric unit. Four significant C-H...O interactions have C...O distances ranging from 3.313 (2) to 3.453 (2) A. They link each molecule directly to eight neighbors, generating a three-dimensional network. The anhydride group is compared with those in phthalic anhydride and 1,4,5,8-naphthalenetetracarboxylic 1,8:4,5-dianhydride.

Hydrogen bonding in 4,4',6,6'-tetramethyl-biphenyl-2,2'-dicarboxylic acid.

The title compound, C18H18O4, crystallizes in the centrosymmetric space group P2(1)/c, with two molecules in the asymmetric unit. Each of the four independent carboxylic H atoms is ordered, and each participates in hydrogen bonding. The OD...OA distances in the hydrogen bonds are 2.598 (3), 2.608 (3), 2.652 (3) and 2.641 (3) A. Two cyclic hydrogen-bonded dimers are found, neither occurring about a center of symmetry; each, however, occurs about a pseudo-center. Numerous hydrogen-bonded chains, all propagating along [010], are also present. The biphenyl twist angles are 88.4 (2) and 87.5 (2) degrees. Structural comparisons are made with the structures of the 'parent' compound, diphenic acid, and its 4,4'- and 6,6'-dimethyl derivatives.

Hydrogen bonding in 4-aminohippuric acid.

The title acid, C9H10N2O3, crystallized in the non-centrosymmetric space group P2(1)2(1)2(1) with one molecule in the asymmetric unit. Four hydrogen bonds occur whose donor-acceptor distances are: O1...O3 2.630 (2), N1...O3 3.090 (2), N2...O1 3.099 (2), and N2...O2 3.022 (2) A, and whose angles fall in the range 163 (2)-173 (2) degrees. The H atoms in these bonds are ordered. Cyclic hydrogen-bonded dimers are not formed; through second-level graphs, only hydrogen-bonded chains occur. These form a strongly three-dimensional array of hydrogen bonds. The dihedral angle between the core plane and the carboxyl plane is 54.8 (2) degrees, and between the core plane and the plane of the amino group, 34 (1) degree. The structure is compared with a previous determination by Chakrabarti & Dattagupta [Z. Kristallogr. (1993), 207, 53-58] and with the structure of the parent molecule, hippuric acid.

Hydrogen bonding in (2R,3R)-(+)-2,3-dimethoxybutanedioic acid [(+)-tartaric acid dimethyl ether].

The title acid, C6H10O6, crystallized in the non-centrosymmetric space group I2, with half a molecule in the asymmetric unit (the molecular symmetry is 2). In the single type of hydrogen bond, the carboxylic H atom is ordered, and the OD...OA distance is 2.665 (2) A. Each molecule is linked to four others by hydrogen bonds and to two others by C-H...O interactions. The dihedral angle between intramolecular carboxyl-group planes is 85.2 (1) degree.

Dineopentylprehnitene (1,2,3,4-tetramethyl-5,6-dineopentylbenzene) at 296 and 223 K.

The title substance, C20H34, crystallized in the centrosymmetric space group C2/c with a single molecule as the asymmetric unit. The molecule is quite crowded intramolecularly, and has a notably non-planar benzene ring. There is, however, virtually no intermolecular crowding.

6,6'-Dimethoxy-3,3',5,5'-tetramethylbiphenyl-2,2'-dimethanol.

The title compound, C20H26O4, crystallized in the centrosymmetric space group P21/c with a single molecule as the asymmetric unit. The two hydroxyl-H atoms are ordered and are involved in hydrogen bonds whose OD...OA distances are 2.807 (2) and 2.805 (2) A; one of these bonds is intramolecular. The intramolecular dihedral angle between the ring planes (twist angle) is 87.3 (1) degree.