Management of chronic primary pelvic pain syndromes.

Management of chronic pelvic pain (CPP) remains a huge challenge for care providers and a major burden for healthcare systems. Treating chronic pain that has no obvious cause warrants an understanding of the difficulties in managing these conditions. Chronic pain has recently been accepted as a disease in its own right by the World Health Organization, with chronic pain without obvious cause being classified as chronic primary pain. Despite innumerable treatments that have been proposed and tried to date for CPP, unimodal therapeutic options are mostly unsuccessful, especially in unselected individuals. In contrast, individualised multimodal management of CPP seems the most promising approach and may lead to an acceptable situation for a large proportion of patients. In the present review, the interdisciplinary and interprofessional European Association of Urology Chronic Pelvic Pain Guideline Group gives a contemporary overview of the most important concepts to successfully diagnose and treat this challenging disease.

Experimental and Computational Studies of Unimolecular 1,1-HX (X = F, Cl) Elimination Reactions of C2D5CHFCl: Role of Carbene:HF and HCl Adducts in the Exit Channel of RCHFCl and RCHCl2 Reactions.

The gas-phase unimolecular reactions of C2D5CHFCl molecules with 94 kcal mol-1 of vibrational energy have been studied by the chemical-activation experimental technique and by electronic-structure computations. Products from the reaction of C2D5CHFCl molecules, formed by the recombination of C2D5 and CHFCl radicals in a room temperature bath gas, were measured by gas chromatography-mass spectrometry. The 2,1-DCl (81%) and 1,1-HCl (17%) elimination reactions are the principal processes, but 2,1-DF and 1,1-HF elimination reactions also are observed. Comparison of experimental rate constants to calculated statistical rate constants provides threshold energies. The potential surfaces associated with C2D5(F)C: + HCl and C2D5(Cl)C: + HF reactions are of special interest because hydrogen-bonded adducts with HCl and HF with dissociation energies of 6.4 and 9.3 kcal mol-1, respectively, are predicted by calculations. The relationship between the geometries and threshold energies of transition states for 1,1-HCl elimination and carbene:HCl adducts is complex, and previous studies of related molecules, such as CD3CHFCl, CD2ClCHFCl, C2D5CHCl2, and halogenated methanes are included in the computational analysis. Extensive calculations for CH3CHFCl as a model for 1,1-HCl reactions illustrate properties of the exit-channel potential energy surface. Since the 1,1-HCl transition state is submerged relative to dissociation of the adduct, inner and outer transition states should be considered for analysis of rate constants describing 1,1-HCl elimination and addition reactions of carbenes to HCl.

Unimolecular HBr and HF Elimination Reactions of Vibrationally Excited C2H5CH2Br and C2D5CHFBr: Identification of the 1,1-HBr Elimination Reaction from C2D5CHFBr and Search for the C2D5(F)C:HBr Adduct.

Chemical activation experiments and computational methods have been used to study the unimolecular reactions of C2H5CH2Br and C2D5CHFBr with 90 and 93 kcal mol-1 of vibrational energy, respectively. The four-centered elimination reactions of HBr and DBr are the dominant reactions; however, 2,1-DF, 1,1-HBr, and 1,1-HF reactions are also observed from C2D5CHFBr. The main focus was to search for the role of the C2D5(F)C:HBr adduct in the 1,1-HBr elimination for comparison with carbene adducts in 1,1-HX(Y) elimination from RCHXY (X,Y = Cl and F) molecules. Models of transition states and molecules from electronic structure calculations were used in statistical calculations of the rate constants to assign threshold energies for each reaction based on the experimental rate constants. The threshold energy for 2,1-HBr elimination from 1-bromopropane is 50 kcal mol-1, which is in basic agreement with thermal activation experiments. Comparison of the 2,1-DBr and 2,1-HBr rate constants permits discussion of the kinetic isotope effects and the effect of F atom substitution on the threshold energy for 2,1-HBr elimination. Although CD3CD═CDF from 1,1-HBr elimination of C2D5CHFBr followed by D atom migration is an experimentally observed product, dissociation of the C2D5(F)C:HBr adduct may be the rate-limiting step rather than crossing the barrier associated with the transition state for 1,1-HBr elimination. The calculated dissociation energies of C2H5(X)C:HF adducts are 9.9, 9.3, and 9.0 kcal mol-1 for X = F, Cl, and Br, and the values for C2H5(F)C:HX are 9.9, 6.4, and ∼4.9 kcal mol-1.

A Broadband Mid-Infrared Trace Gas Sensor Using Supercontinuum Light Source: Applications for Real-Time Quality Control for Fruit Storage.

We present a fully integrated and transportable multi-species trace gas sensor based on a mid-infrared (MIR) supercontinuum light source. The high brightness (surpassing synchrotron) and ultra-broad spectral bandwidth (2-4 µm) of this light source allows simultaneous detection of multiple broadband absorbing gas species. High sensitivity in the sub-ppmv level has been achieved by utilizing an astigmatic multipass cell. A grating-based spectrometer at a scanning rate of 20 Hz is developed employing a balanced detection scheme. A multi-component global fitting algorithm is implemented into a central LabVIEW program to perform real-time data analysis. The obtained concentration values are validated by the standard gas chromatography mass spectrometry (GC-MS) method. Field application of the sensor for quality control of stored fruits at a small scale is demonstrated, involving the detection of ethylene, ethanol, ethyl acetate, acetaldehyde, methanol, acetone, and water simultaneously. The sensor also shows promising potentials for other applications, such as environmental monitoring and biomedical research.

Down-regulation of respiration in pear fruit depends on temperature.

The respiration rate of plant tissues decreases when the amount of available O2 is reduced. There is, however, a debate on whether the respiration rate is controlled either by diffusion limitation of oxygen or through regulatory processes at the level of the transcriptome. We used experimental and modelling approaches to demonstrate that both diffusion limitation and metabolic regulation affect the response of respiration of bulky plant organs such as fruit to reduced O2 levels in the surrounding atmosphere. Diffusion limitation greatly affects fruit respiration at high temperature, but at low temperature respiration is reduced through a regulatory process, presumably a response to a signal generated by a plant oxygen sensor. The response of respiration to O2 is time dependent and is highly sensitive, particularly at low O2 levels in the surrounding atmosphere. Down-regulation of the respiration at low temperatures may save internal O2 and relieve hypoxic conditions in the fruit.

Analysis of the Five Unimolecular Reaction Pathways of CD2ClCHFCl with Emphasis on CD2Cl(F)C: and CD2Cl(Cl)C: Formed by 1,1-HCl and 1,1-HF Elimination.

The five unimolecular HX and DX (X = F, Cl) elimination pathways of CD2ClCHFCl* were examined using a chemical activation technique; the molecules were generated with 92 kcal mol-1 of vibrational energy in a room-temperature bath gas by a combination of CD2Cl and CHFCl radicals. The total unimolecular rate constant was 9.7 × 107 s-1, and branching fractions for each channel were 0.52 (2,1-DCl), 0.29 (1,1-HCl), 0.10 (2,1-DF), 0.07 (1,1-HF), and 0.02 (1,2-HCl). Comparison of the individual experimental rate constants to calculated statistical rate constants gave threshold energies for each process as 63, 72, 66, 73, and 70 kcal mol-1, listed in the same order as the branching fractions. The 1,1-HCl and 1,1-HF reactions gave carbenes, CD2Cl(F)C: and CD2Cl(Cl)C:, respectively, as products, which have hydrogen-bonded complexes with HCl or HF in the exit channel of the potential energy surface. These carbenes have energy in excess of the threshold energy for D atom migration to give CDCl═CDF and CDCl═CDCl, and the subsequent cis-trans isomerization rates of the dihaloethenes can provide information about energy disposal by the 1,1-HX elimination reactions. Electronic structure calculations provide information for transition states of CD2ClCHFCl and hydrogen-bonded complexes of carbenes with HF and HCl. In addition, D atom migration in both free carbenes and in complexes formed by the carbene hydrogen bonding to HCl or HF is explored.

The Unimolecular Reactions of CF3CHF2 Studied by Chemical Activation: Assignment of Rate Constants and Threshold Energies to the 1,2-H Atom Transfer, 1,1-HF and 1,2-HF Elimination Reactions, and the Dependence of Threshold Energies on the Number of F-Atom Substituents in the Fluoroethane Molecules.

The recombination of CF3 and CHF2 radicals in a room-temperature bath gas was used to prepare vibrationally excited CF3CHF2* molecules with 101 kcal mol-1 of vibrational energy. The subsequent 1,2-H atom transfer and 1,1-HF and 1,2-HF elimination reactions were observed as a function of bath gas pressure by following the CHF3, CF3(F)C: and C2F4 product concentrations by gas chromatography using a mass spectrometer as the detector. The singlet CF3(F)C: concentration was measured by trapping the carbene with trans-2-butene. The experimental rate constants are 3.6 × 104, 4.7 × 104, and 1.1 × 104 s-1 for the 1,2-H atom transfer and 1,1-HF and 1,2-HF elimination reactions, respectively. These experimental rate constants were matched to statistical RRKM calculated rate constants to assign threshold energies (E0) of 88 ± 2, 88 ± 2, and 87 ± 2 kcal mol-1 to the three reactions. Pentafluoroethane is the only fluoroethane that has a competitive H atom transfer decomposition reaction, and it is the only example with 1,1-HF elimination being more important than 1,2-HF elimination. The trend of increasing threshold energies for both 1,1-HF and 1,2-HF processes with the number of F atoms in the fluoroethane molecule is summarized and investigated with electronic-structure calculations. Examination of the intrinsic reaction coordinate associated with the 1,1-HF elimination reaction found an adduct between CF3(F)C: and HF in the exit channel with a dissociation energy of ∼5 kcal mol-1. Hydrogen-bonded complexes between HF and the H atom migration transition state of CH3(F)C: and the F atom migration transition state of CF3(F)C: also were found by the calculations. The role that these carbene-HF complexes could play in 1,1-HF elimination reactions is discussed.

A mechanistic modelling approach to understand 1-MCP inhibition of ethylene action and quality changes during ripening of apples.

BACKGROUND: 1-Methylcyclopropene (1-MCP) inhibits ripening in climacteric fruit by blocking ethylene receptors, preventing ethylene from binding and eliciting its action. The objective of the current study was to use mathematical models to describe 1-MCP inhibition of apple fruit ripening, and to provide a tool for predicting ethylene production, and two important quality indicators of apple fruit, firmness and background colour. RESULTS: A model consisting of coupled differential equations describing 1-MCP inhibition of apple ripening was developed. Data on ethylene production, expression of ethylene receptors, firmness, and background colour during ripening of untreated and 1-MCP treated apples were used to calibrate the model. An overall adjusted R2 of 95% was obtained. The impact of time from harvest to treatment, and harvest maturity on 1-MCP efficacy was modelled. Different hypotheses on the partial response of 'Jonagold' apple to 1-MCP treatment were tested using the model. The model was validated using an independent dataset. CONCLUSIONS: Low 1-MCP blocking efficacy was shown to be the most likely cause of partial response for delayed 1-MCP treatment, and 1-MCP treatment of late-picked apples. Time from harvest to treatment was a more important factor than maturity for 1-MCP efficacy in 'Jonagold' apples. © 2017 Society of Chemical Industry.

Comprehensive Mutation Analysis of PMS2 in a Large Cohort of Probands Suspected of Lynch Syndrome or Constitutional Mismatch Repair Deficiency Syndrome.

Monoallelic PMS2 germline mutations cause 5%-15% of Lynch syndrome, a midlife cancer predisposition, whereas biallelic PMS2 mutations cause approximately 60% of constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer syndrome. Recently improved DNA- and RNA-based strategies are applied to overcome problematic PMS2 mutation analysis due to the presence of pseudogenes and frequent gene conversion events. Here, we determined PMS2 mutation detection yield and mutation spectrum in a nationwide cohort of 396 probands. Furthermore, we studied concordance between tumor IHC/MSI (immunohistochemistry/microsatellite instability) profile and mutation carrier state. Overall, we found 52 different pathogenic PMS2 variants explaining 121 Lynch syndrome and nine CMMRD patients. In vitro mismatch repair assays suggested pathogenicity for three missense variants. Ninety-one PMS2 mutation carriers (70%) showed isolated loss of PMS2 in their tumors, for 31 (24%) no or inconclusive IHC was available, and eight carriers (6%) showed discordant IHC (presence of PMS2 or loss of both MLH1 and PMS2). Ten cases with isolated PMS2 loss (10%; 10/97) harbored MLH1 mutations. We confirmed that recently improved mutation analysis provides a high yield of PMS2 mutations in patients with isolated loss of PMS2 expression. Application of universal tumor prescreening methods will however miss some PMS2 germline mutation carriers.

Reinvestigation of the Unimolecular Reactions of CHF2CHF2: Identification of the 1,1-HF Elimination Component from Addition of :CFCHF2 to trans-2-Butene.

The recombination of ·CHF2 radicals in a room-temperature bath gas was used to generate CHF2CHF2* (where * indicates vibrational excitation) molecules with 96 kcal mol-1 of vibrational energy. The CHF2CHF2* molecules decompose by four-centered 1,2-HF elimination and by three-centered 1,1-HF elimination reactions to give HF and either CHF═CF2 or :CFCHF2, respectively. The 1,1-HF component was identified by trapping the :CFCHF2 carbene with trans-2-butene that forms 1-fluoro-1-difluoromethyl-2,3-dimethylcyclopropane. The total rate constant for the decomposition of CHF2CHF2* was 6.0 × 105 s-1, and the rate constant for the 1,1-HF pathway forming the carbene, as measured by the 1-fluoro-1-difluoromethyl-2,3-dimethylcyclopropane yield, was 1.4 × 105 s-1. On the basis of matching the experimental rate constants to calculated statistical rate constants, the threshold energies for the four-centered and three-centered reactions are 78 and ≤85 kcal mol-1, respectively.

Chemical Activation Study of the Unimolecular Reactions of CD3CD2CHCl2 and CHCl2CHCl2 with Analysis of the 1,1-HCl Elimination Pathway.

Chemically activated C2D5CHCl2 molecules were generated with 88 kcal mol-1 of vibrational energy by the recombination of C2D5 and CHCl2 radicals in a room temperature bath gas. The competing 2,1-DCl and 1,1-HCl unimolecular reactions were identified by the observation of the CD3CD═CHCl and CD3CD═CDCl products. The initial CD3CD2C-Cl carbene product from 1,1-HCl elimination rearranges to CD3CD═CDCl under the conditions of the experiments. The experimental rate constants were 2.7 × 107 and 0.47 × 107 s-1 for 2,1-DCl and 1,1-HCl elimination reactions, respectively, which corresponds to branching fractions of 0.84 and 0.16. The experimental rate constants were compared to calculated statistical rate constants to assign threshold energies of 54 and ≈66 kcal mol-1 for the 1,2-DCl and 1,1-HCl reactions, respectively. The statistical rate constants were obtained from models developed from electronic-structure calculations for the molecule and its transition states. The rate constant (5.3 × 107 s-1) for the unimolecular decomposition of CHCl2CHCl2 molecules formed with 82 kcal mol-1 of vibrational energy by the recombination of CHCl2 radicals also is reported. On the basis of the magnitude of the calculated rate constant, 1,1-HCl elimination must contribute less than 15% to the reaction; 1,2-HCl elimination is the major reaction and the threshold energy is 59 kcal mol-1. Calculations also were done to analyze previously published rate constants for chemically activated CD2ClCHCl2 molecules with 86 kcal mol-1 of energy to obtain a better overall description of the nature of the 1,1-HCl pathway for 1,1-dichloroalkanes. The interplay of the threshold energies for the 2,1-HCl and 1,1-HCl reactions and the available energy determines the product branching fractions for individual molecules. The unusual nature of the transition state for 1,1-HCl elimination is discussed.

Automatic analysis of the 3-D microstructure of fruit parenchyma tissue using X-ray micro-CT explains differences in aeration.

BACKGROUND: 3D high-resolution X-ray imaging methods have emerged over the last years for visualising the anatomy of tissue samples without substantial sample preparation. Quantitative analysis of cells and intercellular spaces in these images has, however, been difficult and was largely based on manual image processing. We present here an automated procedure for processing high-resolution X-ray images of parenchyma tissues of apple (Malus × domestica Borkh.) and pear (Pyrus communis L.) as a rapid objective method for characterizing 3D plant tissue anatomy at the level of single cells and intercellular spaces. RESULTS: We isolated neighboring cells in 3D images of apple and pear cortex tissues, and constructed a virtual sieve to discard incorrectly segmented cell particles or unseparated clumps of cells. Void networks were stripped down until their essential connectivity features remained. Statistical analysis of structural parameters showed significant differences between genotypes in the void and cell networks that relate to differences in aeration properties of the tissues. CONCLUSIONS: A new model for effective oxygen diffusivity of parenchyma tissue is proposed that not only accounts for the tortuosity of interconnected voids, but also for significant diffusion across cells where the void network is not connected. This will significantly aid interpretation and analysis of future tissue aeration studies. The automated image analysis methodology will also support pheno- and genotyping studies where the 3D tissue anatomy plays a role.

Characterization of the 1,1-HF Elimination Reaction from the Competition between the 1,1-HF and 1,2-DF Unimolecular Elimination Reactions of CD3CD2CHF2.

The recombination of CHF2 and C2D5 radicals was used to produce CD3CD2CHF2* molecules with 96 kcal mol(-1) of vibrational energy in a room temperature bath gas. The formation of CD3CD═CHF and CD3CD═CDF was used to identify the 1,2-DF and 1,1-HF unimolecular elimination channels; CD3CD═CDF is formed by isomerization of the singlet-state CD3CD2CF carbene. The total unimolecular rate constant is 1.6 × 10(6) s(-1), and the branching ratio for 1,1-HF elimination is 0.25. Threshold energies of 64 ± 2 and 73 ± 2 kcal mol(-1) were assigned to the 1,2-DF and 1,1-HF reaction channels. The E and Z isomers of 1-fluoropropene were observed for each reaction; approximately 30% of the CD3CD═CDF molecules derived from 1,1-HF elimination retained enough energy to undergo cis-trans isomerization. Electronic structure calculations with density-functional theory were used to characterize the transition-state structures and the H atom migration barrier for CD3CD2CF. Adjustment of the rate constants to account for kinetic-isotope effects suggest that the branching ratio would be 0.20 for 1,1-HF elimination from C2H5CHF2. The results from an earlier study of CD3CHF2 and CH3CHF2 are also reinterpreted to assign a threshold energy of 74 kcal mol(-1) for the 1,1-HF elimination reaction. Because CHF2CHF2* is generated in the photolysis system, the 1,1-and 1,2-HF-elimination reactions of CHF2CHF2* are discussed. The 1,1-HF channel was identified by trapping the CF2HCF carbene with cis-butene-2.

Characterization of the 1,1-HCl Elimination Reaction of Vibrationally Excited CD3CHFCl Molecules and Assignment of Threshold Energies for 1,1-HCl and 1,2-DCl plus 1,1-HF and 1,2-DF Elimination Reactions.

Vibrationally excited CD3CHFCl molecules with 96 kcal mol(-1) of energy were generated by the recombination of CD3 and CHFCl radicals in a room-temperature bath gas. The four competing unimolecular decomposition reactions, namely, 1,1-HCl and 1,2-DCl elimination and 1,1-HF and 1,2-DF elimination, were observed, and the individual rate constants were measured. The product branching fractions are 0.60, 0.27, 0.09, and 0.04 for 1,2-DCl, 1,1-HCl, 1,2-DF, and 1,1-HF elimination, respectively. Electronic structure calculations were used to define models of the four transition states. The statistical rate constants calculated from these models were compared to the experimental rate constants. The assigned threshold energies with ±2 kcal mol(-1) uncertainty are 60, 72, 65, and 74 kcal mol(-1) for the 1,2-DCl, 1,1-HCl, 1,2-DF, and 1,1-HF reactions, respectively. The loose structure of the 1,1-HX transition states, which is exemplified by the order of magnitude larger pre-exponential factor relative to the 1,2-HX elimination reactions, compensates for the high threshold energy; thus, the 1,1-HX elimination reaction rates can compete with the 1,2-HX elimination reactions for high levels of vibrational excitation in CD3CHFCl. The 1,1-HCl and 1,1-HF reactions are observed via the CD2═CDF and CD2═CDCl products formed from isomerization of the CD3CF and CD3CCl carbenes. These D-atom migration reactions are discussed, and the possibility of tunneling is evaluated. The transition states developed from the 1,1-HCl and 1,1-HF reactions of CD3CHFCl are compared to models for the HCl and HF elimination reactions of CHF2Cl, CHFCl2, and CH2FCl.

Outbreak of Trichinella spiralis infections associated with a wild boar hunted at a game farm in Iowa.

BACKGROUND: Rates of trichinellosis have declined significantly in the United States due to improved pork production practices and public awareness of the danger of eating raw or undercooked pork. In April 2011, the Minnesota Department of Health received a report of presumptive trichinellosis in a 50-year-old man with a history of wild boar consumption. A public health investigation was initiated. METHODS: Medical record reviews and patient and family interviews were conducted. Trichinella species serology was performed on patient and family serum samples, and larval identification was attempted on clinical specimens and meat samples. RESULTS: The index patient harvested a wild boar from an Iowa game farm; he processed the meat after returning home and developed gastrointestinal symptoms 2 days later. Four days after his illness onset, all 5 family members consumed a roast from the boar. The index patient sought healthcare 4 times after illness onset before being definitively diagnosed with trichinellosis. Following initiation of albendazole therapy, the index patient developed atrial fibrillation. One additional family member who processed the raw meat was diagnosed with trichinellosis. Trichinella spiralis larvae were identified in wild boar meat samples. CONCLUSIONS: Trichinellosis has long been recognized as a potential hazard of consuming undercooked wild carnivore meat, and historically has been associated with consumption of pork from domestic swine, but may be unfamiliar to practicing clinicians in the United States. Education of hunters and the broader population on the potential for trichinellosis and the importance of proper handling and cooking meat from wild or free-range animals needs to be reinforced.

Unimolecular reactions of 1,1,1-trichloroethane, 1,1,1-trichloropropane, and 3,3,3-trifluoro-1,1,1-trichloropropane: determination of threshold energies by chemical activation.

The recombination of CCl3 radicals with CH3, CH3CH2, and CF3CH2 radicals was used to generate CH3CCl3, CH3CH2CCl3, and CF3CH2CCl3 molecules with approximately 87 kcal mol(-1) of vibrational energy in a bath gas at room temperature. The competition between collisional deactivation and unimolecular reaction by HCl elimination was used to obtain the experimental rate constants for each molecule. These experimental rate constants were matched to calculated statistical unimolecular rate constants to assign threshold energies to the three HCl elimination reactions. The models needed for the calculations of the rate constants were obtained from molecular structure calculations using density functional theory (DFT) with the hybrid density-functional MO6-2X recommended by Truhlar for transition states. The assigned threshold energies are 52 ± 2, 50 ± 2, and 52 ± 2 kcal mol(-1) for CH3CCl3, CH3CH2CCl3, and CF3CH2CCl3, respectively, and the CH3 and CF3 groups have only a minor effect on the threshold energies for HCl elimination. The DFT calculated threshold energies are in agreement with the experimentally assigned values. The addition of Cl atoms to the same carbon atom lowers the threshold energy for HCl elimination in the CH3CH2Cl, CH3CHCl2, and CH3CCl3 series. This trend, which is the opposite of that for CH3CH2F, CH3CHF2, and CH3CF3, is discussed in terms of transition-state structure and correlated with the relative stabilities of CH3CH2(+), CH3CHCl(+), and CH3CCl2(+) ions; the relative stabilities are based on the hydride affinities obtained from calculations. Comparison of the reactions of CH3CCl3 and CH2ClCHCl2 shows that the threshold energy is much higher for the isomer with chlorine atoms on both carbon atoms.

Effects of CF(3) and CH(3) groups on the threshold energy for the unimolecular interchange reaction of Cl- and F-atoms in CF(3)CHFCH(2)Cl and CH(3)CHFCH(2)Cl.

The recombination reactions of CH2Cl radicals with CF3CHF and with CH3CHF radicals were used to generate CF3CHFCH2Cl and CH3CHFCH2Cl molecules with 90-92 kcal mol(-1) of vibrational energy. The experimental rate constants for elimination of HCl and HF and the interchange of Cl and F atoms were measured and compared to RRKM calculated rate constants to assign the threshold energy for each unimolecular reaction channel. The Cl/F interchange reaction is approximately 18% of the total unimolecular reaction for both molecules. The product branching ratios and some rate constants also could be measured for the unimolecular reactions of the rearranged molecules, CF3CHClCH2F and CH3CHClCH2F. The most important result is that the CH3 group lowers the threshold for Cl/F interchange relative to CH2FCD2Cl, as expected for an electron-density donating group, and the CF3 group, an electron-density withdrawing group, increases the threshold energy relative to CH2FCD2Cl. The CH3 and CF3 groups alter the threshold energies of the HCl and HF elimination reactions in such a way so as to maintain the same branching fraction for the interchange reaction. The results from density functional theory using the B3PW91 method with the 6311+G(2d,p) and G-31G(d',p') basis sets are used to discuss the trends in threshold energies for the Cl/F interchange and the HF and HCl elimination reactions.

Unimolecular isomerization of CH2FCD2Cl via the interchange of Cl and F atoms: assignment of the threshold energy to the 1,2-dyotropic rearrangement.

The room-temperature gas-phase recombination of CH2F and CD2Cl radicals was used to prepare CH2FCD2Cl molecules with 91 kcal mol(-1) of vibrational energy. Three unimolecular processes are in competition with collisional deactivation of CH2FCD2Cl; HCl and DF elimination to give CHF═CD2 and CH2═CDCl plus isomerization to give CH2ClCD2F by the interchange of F and Cl atoms. The Cl/F interchange reaction was observed, and the rate constant was assigned from measurement of CHCl═CD2 as a product, which is formed by HF elimination from CH2ClCD2F. These experiments plus previously published results from chemically activated CH2ClCH2F and electronic structure and RRKM calculations for the kinetic-isotope effects permit assignment of the three rate constants for CH2FCD2Cl (and for CH2ClCD2F). The product branching ratio for the interchange reaction versus elimination is 0.24 ± 0.04. Comparison of the experimental rate constant with the RRKM calculated rate constant permitted the assignment of a threshold energy of 62 ± 3 kcal mol(-1) for this type-1 dyotropic rearrangement. On the basis of electronic structure calculations, the nature of the transition state for the rearrangement reaction is discussed. The radical recombination reactions in the chemical system also generate vibrationally excited CD2ClCD2Cl and CH2FCH2F molecules, and the rate constants for DCl and HF elimination were measured in order to confirm that the photolysis of CD2ClI and (CH2F)2CO mixtures was giving reliable data for CH2FCD2Cl.

Development and psychometric properties of the DCDDaily: a new test for clinical assessment of capacity in activities of daily living in children with developmental coordination disorder.

OBJECTIVE: To develop the DCDDaily, an instrument for objective and standardized clinical assessment of capacity in activities of daily living (ADL) in children with developmental coordination disorder (DCD), and to investigate its usability, reliability, and validity. SUBJECTS: Five to eight-year-old children with and without DCD. MAIN MEASURES: The DCDDaily was developed based on thorough review of the literature and extensive expert involvement. To investigate the usability (assessment time and feasibility), reliability (internal consistency and repeatability), and validity (concurrent and discriminant validity) of the DCDDaily, children were assessed with the DCDDaily and the Movement Assessment Battery for Children-2 Test, and their parents filled in the Movement Assessment Battery for Children-2 Checklist and Developmental Coordination Disorder Questionnaire. RESULTS: 459 children were assessed (DCD group, n = 55; normative reference group, n = 404). Assessment was possible within 30 minutes and in any clinical setting. For internal consistency, Cronbach's α = 0.83. Intraclass correlation = 0.87 for test-retest reliability and 0.89 for inter-rater reliability. Concurrent correlations with Movement Assessment Battery for Children-2 Test and questionnaires were ρ = -0.494, 0.239, and -0.284, p < 0.001. Discriminant validity measures showed significantly worse performance in the DCD group than in the control group (mean (SD) score 33 (5.6) versus 26 (4.3), p < 0.001). The area under curve characteristic = 0.872, sensitivity and specificity were 80%. CONCLUSIONS: The DCDDaily is a valid and reliable instrument for clinical assessment of capacity in ADL, that is feasible for use in clinical practice.

[Genetic regulation of plant shoot stem cells].

This article describes the main features of plant stem cells and summarizes the results of studies of the genetic control of stem cell maintenance in the apical meristem of the shoot. It is demonstrated that the WUS-CLV gene system plays a key role in the maintenance of shoot apical stem cells and the formation of adventitious buds and somatic embryos. Unconventional concepts of plant stem cells are considered.