Temperature-Dependent Order-Disorder Phenomena in Crystal Structures Containing Dimers of Carboxylic Acids: The Crystal and Molecular Structure of 3,5-Dinitrobenzoic Acid at Room and Liquid Nitrogen Temperature and Statistics of the Geometries of Hydrogen-Bonded Carboxyl Groups

3,5-dinitrobenzoic acid crystallizes in space group P2i/c with four molecules in the unit cell. At room temperature (RT), the cell dimensions are a = 10.0237(4), b = 8.8728(3), c = 9.5090(4) A, = 95.68(1)° and V = 841.56(6) A3 and at liquid nitrogen temperature (LNT) a = 9.761(2), b = 8.9192(4), c = 9.444(2) A, /S = 97.55(1)° and V = 815.1(2) A3. At both temperatures, the crystals contain the common centrosymmetric carboxylic acid dimers. At RT the carboxyl groups are partially disordered, as indicated by the C=0 [1.249(3)] and C-0 [1.276(2)A] distances, C-C = 0 [118.4(2)1 and C-C-0 [116.4(2)°] angles and by the presence of disordered H atoms with occupancy factors of 0.63 and 0.37 in the O—O hydrogen bond. At LNT, the acidic proton is ordered with a distance of 0.96(2) A from the donor hydroxyl O atom and the carboxyl group geometry is normal, with C=0 1.232(2) and C-0 1.305(2) A and C-C = 0 120.6(1) and C-C-O 114.4(1)°. The differences Ar distances and A of the C-C-O angles are 0.027 A and 2.0°, respectively, at RT and 0.073 A and 6.2°, respectively, at LNT, which indicates an increase of ordering with decreasing temperature. The mechanism of disordering most probably invokes a temperature-dependent concerted two-proton jump across the dimer hydrogen bonds. To test the relationship between Ar and A, a statistical analysis is performed on the C-0 distances and C-C-O angles of RT and LNT dimer and non-dimer structures retrieved from the Cambridge Structural Database. The analysis indicates that disorder in RT dimers is more frequent than in RT non-dimers and also that ordering is pronounced in both LT dimer and non-dimer structures

Temperature-Dependent Order-Disorder Phenomena in Crystal Structures Containing Dimers of Carboxylic Acids: The Crystal and Molecular Structure of 3,5-Dinitrobenzoic Acid at Room and Liquid Nitrogen Temperature and Statistics of the Geometries of Hydrogen-Bonded Carboxyl Groups

3,5-dinitrobenzoic acid crystallizes in space group P2i/c with four molecules in the unit cell. At room temperature (RT), the cell dimensions are a = 10.0237(4), b = 8.8728(3), c = 9.5090(4) A, = 95.68(1)° and V = 841.56(6) A3 and at liquid nitrogen temperature (LNT) a = 9.761(2), b = 8.9192(4), c = 9.444(2) A, /S = 97.55(1)° and V = 815.1(2) A3. At both temperatures, the crystals contain the common centrosymmetric carboxylic acid dimers. At RT the carboxyl groups are partially disordered, as indicated by the C=0 [1.249(3)] and C-0 [1.276(2)A] distances, C-C = 0 [118.4(2)1 and C-C-0 [116.4(2)°] angles and by the presence of disordered H atoms with occupancy factors of 0.63 and 0.37 in the O—O hydrogen bond. At LNT, the acidic proton is ordered with a distance of 0.96(2) A from the donor hydroxyl O atom and the carboxyl group geometry is normal, with C=0 1.232(2) and C-0 1.305(2) A and C-C = 0 120.6(1) and C-C-O 114.4(1)°. The differences Ar distances and A of the C-C-O angles are 0.027 A and 2.0°, respectively, at RT and 0.073 A and 6.2°, respectively, at LNT, which indicates an increase of ordering with decreasing temperature. The mechanism of disordering most probably invokes a temperature-dependent concerted two-proton jump across the dimer hydrogen bonds. To test the relationship between Ar and A, a statistical analysis is performed on the C-0 distances and C-C-O angles of RT and LNT dimer and non-dimer structures retrieved from the Cambridge Structural Database. The analysis indicates that disorder in RT dimers is more frequent than in RT non-dimers and also that ordering is pronounced in both LT dimer and non-dimer structures

A systematic knowledge synthesis on the spatial dimensions of Q fever epidemics

From 2007 through 2010, the Netherlands experienced the largest Q fever epidemic ever reported. This study integrates the outcomes of a multidisciplinary research programme on spatial airborne transmission of Coxiella burnetii and reflects these outcomes in relation to other scientific Q fever studies worldwide. We have identified lessons learned and remaining knowledge gaps. This synthesis was structured according to the four steps of quantitative microbial risk assessment (QMRA): (a) Rapid source identification was improved by newly developed techniques using mathematical disease modelling; (b) source characterization efforts improved knowledge but did not provide accurate C. burnetii emission patterns; (c) ambient air sampling, dispersion and spatial modelling promoted exposure assessment; and (d) risk characterization was enabled by applying refined dose-response analyses. The results may support proper and timely risk assessment and risk management during future outbreaks, provided that accurate and structured data are available and exchanged readily between responsible actors