Toxin detection and screening could contribute to knowledge of the transmission patterns, risk factors epidemiology Clostridium difficile perfringens.To isolate C. perfringens detect A/B toxins in faecal samples from diarrhoeic nondiarrhoeic foals.Cross-sectional observational study.A total 153 foals were collected: 139 farms 14 admitted a veterinary hospital. The detected by cytotoxicity assay. All suspected colonies subjected polymerase chain reaction for major toxin genes (α, β, ε ι) β2-,...

Phosphorus plays an essential role in the chemistry of living organisms, being present several fundamental biomolecules. The investigation chemical reactions taking place different astronomical environments involving phosphorus-containing molecules is for understanding how these species are produced and destroyed. Ultimately, it can help unravel pathways that lead to important prebiotic molecules. monoxide (PO) phosphorus nitride (PN) key reservoirs Interstellar Medium (ISM). Understanding...

A new procedure is suggested to improve genetic algorithms for the prediction of structures nanoparticles. The strategy focuses on managing creation individuals by evaluating efficiency operators (o1, o2,…,o13) in generating well-adapted offspring. This done increasing rate with better performance and decreasing that ones which poorly fulfill task creating favorable generation. Additionally, several strategies (thirteen at this level approach) from different optimization techniques were...

A genetic algorithm coupled to electronic structure calculations is developed for searching the global minimum in ab initio potential energy landscape of alloy clusters. The convergence criterion gradient local optimization progressively reduced over generations order require less evaluations. case studied Na–K with MP2/ECP energies, where it demonstrated that efficient obtaining minima. Particular analysis a 2D–3D–2D transition 6-atoms detail first time. Completely new structures are unveiled larger

Genetic algorithm is employed to survey an empirical potential energy surface for small Na(x)K(y) clusters with x + y ≤ 15, providing initial conditions electronic structure methods. The minima of such are assessed and corrected using high level ab initio methods as CCSD(T), CR-CCSD(T)-L MP2, benchmark results obtained specific cases. the first calculations alloy may serve a reference further studies. validity choice proper functional basis set DFT then explored data, where it was found that...

ABSTRACT Models for the abundances of phosphorus-bearing molecules, such as PO and PN, rely on rate coefficients guessed from similar reactions NO. Given importance these molecules in pre-biotic chemistry, this work we carry out accurate multireference configuration interaction calculations N+PO O+PN reactions, unravelling their underlying mechanisms potential energy barriers. The collisions may occur two triplet electronic states involve six wells lying under limit. between atomic nitrogen...

The silyl cyanide (SiH3CN) molecule, the simplest representative of a fully saturated silacyanide, was prepared in gas phase under single-collision conditions via radical substitution mechanism. chemical dynamics were direct and revealed pronounced backward scattering as consequence transition state with pentacoordinated silicon atom almost colinear geometry attacking cyano leaving hydrogen. Compared to isovalent (CN)-methane (CH4) system, CN-SiH4 system dramatically reduces energy by nearly...

The potential application of all-nitrogen molecules as high energy density materials (HEDMs) has been attracting considerable scientific effort. If stable enough to be synthesized and stored, these systems may used a green source energy. However, it is very difficult obtain structures under mild experimental conditions. Theoretical chemistry aid in the search for polynitrogens that are more likely have usability. barriers towards decomposition an effective way assess their stability, but not...

ABSTRACT The Si + SO2 reaction is investigated to verify its impact on the abundances of molecules with astrochemical interest, such as SiS, SiO, SO, and others. According our results Si(3P) react barrierlessly yielding only monoxides SO SiO products. No favourable pathway has been found leading other products, this should not contribute SiS abundance. Furthermore, it predicted that stable in collisions O2, S(3P) SiO2 O(3P)+OSiS will also produce SiO. Using these gathering further...

Center-of-mass velocity flux contour map for the reaction of D1-silylidyne radical (SiD) with deuterium sulfide (D₂S) leading to gas-phase formation D2-silanethione (D₂SiS).

The phosphinidenesilylene (HPSi; X1A′) molecule was prepared via a directed gas-phase synthesis in the bimolecular reaction of ground-state atomic silicon (Si; 3P) with phosphine (PH3; X1A1) under single-collision conditions. chemical dynamics are initiated on triplet surface addition atom to non-bonding electron pair phosphine, followed by non-adiabatic and hopping singlet manifold, accompanied isomerization hydrogen shift decomposition (HPSi, along molecular hydrogen. Statistical...

Elementary reaction mechanisms constitute a fundamental infrastructure for chemical processes as whole. However, while these are well understood second-period elements, involving those of the third period and beyond can introduce unorthodox reactivity. Combining crossed molecular beam experiments with electronic structure calculations dynamics simulations, we provide compelling evidence on an exotic insertion unsaturated sigma doublet radical into silicon-hydrogen bond observed in...

Periodicity in electronic molar entropy values has been shown on the basis of structures elements. Also, with approximations discussed herein, one can estimate without atomic spectroscopy results. All this be accomplished by showing connection between vector model atom and statistical thermodynamics its quantum mechanical form.

Center-of-mass flux contour map for the reactions of D1-silylidyne radical (SiD; X 2 Π) with phosphine (PH 3 ; 1 A ) leading to formation phosphinidenesilyl (HSiPH/DSiPH) and phosphinosilylidyne (SiPH ).

Abstract A computational investigation of the azide radical formation from two N 2 molecules was carried out employing CASSCF and MRCI electronic structure methods. Potential energy curves were built considering various excited states along proposed reaction coordinates. Reaction paths with C 2v s symmetries considered barriers estimated, as well intersections between key found. possible mechanism is suggested involving a nitrogen atom abstraction to produce linear 3 . The distinction formed...