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The diverse bacterial communities that colonize the gastrointestinal tract play an essential role in maintaining immune homeostasis through the production of critical metabolites such as short-chain fatty acids (SCFAs) and this can be disrupted by antibiotic use. However, few studies have addressed the effects of specific antibiotics longitudinally on the microbiome and immunity. We evaluated the effects of four specific antibiotics: enrofloxacin, cephalexin, paromomycin, and clindamycin, in healthy female rhesus macaques. All antibiotics disrupted the microbiome, including reduced abundances of fermentative bacteria and increased abundances of potentially pathogenic bacteria, including Enterobacteriaceae in the stool, and decreased Helicobacteraceae in the colon. This was associated with decreased SCFAs, indicating altered bacterial metabolism. Importantly, antibiotic use also substantially altered local immune responses, including increased neutrophils and Th17 cells in the colon. Furthermore, we observed increased soluble CD14 in plasma, indicating microbial translocation. These data provide a longitudinal evaluation of antibiotic-induced changes to the composition and function of colonic bacterial communities associated with specific alterations in mucosal and systemic immunity.

There is a desire from the radiation detection community to develop a low-cost method to detect neutron radiation. One potential solution is to measure the 478 keV gamma-ray from the 10B(n, α ) reaction using a spectroscopic gamma-ray detector. Experiments and Monte Carlo N-Particle 6.2 radiation transport simulations were performed for a NaI(Tl) detector surrounded with natural isotopic composition boron carbide powder. The neutron source for the experimental measurements was 241Am–Be.​ Additional MCNP simulations were performed using a 240Pu spontaneous fission neutron source. The experimental results were compared against 3He based measurements and found to be 70% as efficient as the 3He system. The total cost of this modification to an existing NaI(Tl) detector was $65.12. The optimal 10B-NaI(Tl) system design when measuring 240Pu was determined to consist of a 0.5 cm endcap of boron carbide and 6 cm of high-density polyethylene for neutron moderation.

The diverse bacterial communities that colonize the gastrointestinal tract play an essential role in maintaining immune homeostasis through the production of critical metabolites such as short chain fatty acids (SCFA), and this can be disrupted by antibiotic use. However, few studies have addressed the effects of specific antibiotics longitudinally on the microbiome and immunity. We evaluated the effects of four specific antibiotics; enrofloxacin, cephalexin, paromomycin, and clindamycin; in healthy female rhesus macaques. All antibiotics disrupted the microbiome, including reduced abundances of fermentative bacteria and increased abundances of potentially pathogenic bacteria, including Enterobacteriaceae in stool, and decreased Helicobacteraceae in the colon. This was associated with decreased SCFAs, indicating altered bacterial metabolism. Importantly, antibiotic use also substantially altered local immune responses, including increased neutrophils and Th17 cells in the colon. Furthermore, we observed increased soluble-CD14 in plasma, indicating microbial translocation. These data provide a longitudinal evaluation of antibiotic-induced changes to the composition and function of colonic bacterial communities, associated with specific alterations in mucosal and systemic immunity.

A fuel processor was constructed which incorporated two burners with direct steam generation by water injection into the burner exhaust. These burners with direct water vaporization enabled rapid fuel processor start-up for automotive fuel cell systems. The fuel processor consisted of a conventional chain of reactors: auto-thermal reformer (ATR), water gas shift (WGS) reactor and preferential oxidation (PrOx) reactor. The criticality of steam to the fuel reforming process was illustrated. By utilizing direct vaporization of water, and hydrogen for catalyst light-off, excellent start performance was obtained with a start time of 20 s to 30% power and 140 s to full power.

Cationic allyldicarbonyl derivatives of molybdenum and tungsten of the types [M(CO) 2 (η 3 -allyl)(L 3 )PF 6 (M = W, allyl = C 3 H 5 or 2-MeC 3 H 4 , L 3 =bis(2-pyridylmethyl)amine, bpma) and [M(CO) 2 (η 3 -allyl)(L 4 )]PF 6 (M = Mo or W, allyl = C 3 H 5 or 2-MeC 3 H 4 , L4 = tris(2-pyridylmethyl)amine, tpma) have been prepared, and their isomerism and dynamic behaviour in solution examined. In the solid state, [W(CO) 2 (η 3 -C 3 H 5 )(bpma)]PF 6 ( 1a ) exhibits an unsymmetric, and [Mo(CO) 2 (η 3 -C 3 H 5 )(tpma)]PF 6 ( 3 ) a symmetric, orientation of the N-donor set, which comprises two pyridyl rings and the central, exocyclic N of each ligand, with respect to the π-allyl group. The third bipyridyl ring of tpma in the latter complex is orientated away from the metal centre in the solid, but undergoes rapid exchange with N-donors within the coordination sphere at elevated temperatures in solution. Neither of the 2-MeC 3 H 4 analogues of 3 are dynamic under similar conditions, whereas the 2-MeC 3 H 4 analogue of 1 undergoes a facile trigonal twist rearrangement.

The complexes [MoCl(η 3 C 3 H 5 )(CO) 2 (RCN) 2 ], where R = Me or Ph, ionise extensively in both polar and non-polar solvents to [Mo(η 3 C 3 H 5 )(CO) 2 (RCN) 3 ] + [Mo 2 Cl 3 (η 3 C 3 H 5 )2(CO) 4 ] with the liberation of free nitrile. Both cations have been isolated and characterised in the form of hexafluorophosphate salts. The corresponding neutral bromo-complexes [MoBr(η 3 C 3 H 5 )(CO) 2 (RCN) 2 ] ionise similarly although to a lesser extent, whereas the iodises do not. Equilibrium constants for the ionisation reactions, and thermodynamic data for the system [MoCl(η 3 C 3 H 5 )(CO) 2 (PhCN) 2 ]-PhCN, have been calculated.

Dissolution of [MoCl(CO) 2 (η 3 -C 3 H 4 R)(NCMe) 2 ] (R = H or Me) in methanol yields yellow conducting solutions containing the [Mo(CO) 2 (η 3 -C 3 H 4 R)(HOMe) 3 ] + cations. The same species are formed on dissolution of [Mo(CO) 2 (η 3 -C 3 H 4 R)(NCMe) 3 ]BF 4 in methanol, and one of the cations (R = Me) has been isolated as its tetrafluoroborate salt. There is strong spectroscopic evidence that hydrated allyldicarbonylmolybdenum(II) cations [Mo(CO) 2 (η 3 -C 3 H 4 R)(H 2 O) x ] + are present on dissolution of [MoCl(CO) 2 (η 3 -C 3 H 4 R)(NCMe) 2 ] in deoxygenated water, and treatment of these solutions with bi- and tridentate ligands yields neutral complexes [MoCl(CO) 2 (η 3 -C 3 H 4 R)L 2 ] (R = H or Me; L 2 = 2,2′-bipyridine (bipy) or 2,2′-bipyridylamine (bpa)), and cationic species [Mo(CO) 2 (η 3 -C 3 H 4 R)L 3 ] + (R = H or Me; L 3 = diethylenetriamine (dien) or bis(2-pyridylmethyl)amine (bpma)) respectively. The latter were isolated as their hexafluorophosphate salts. Addition of Ph 4 AsCl to basic methanolic solutions of [MoCl(CO) 2 (η 3 -C 3 H 4 R)(NCMe) 2 ] causes the precipitation of the anionic molybdenum derivatives Ph 4 As[Mo 2 (CO) 4 (η 3 -C 3 H 4 R) 2 (μ-OMe) 3 ] (R = H or Me).

Reactions of [WX(η3-C3H5)(CO)2(MeCN)2] with the ditertiary arsines Ph2AsCH2CH2AsPh2 (dae) and Ph2AsCH2CH2AsPh2 (dam) yield complexes of stoichiometry [WX(η3-C3H5)(CO)2dae], (X = Cl, Br or I) and [W2X2(η3-C3H5)2(CO)4dam], (X = Cl or Br). Whereas the former series of complexes contain chelating dae, the latter contain dam bridges which are readily cleaved by pyridine (py), the ditertiary phosphines Ph2PCH2PPh2 (dpm) and Ph2PCH2CH2PPh2 (dpe), or chloride ions to give [WX(η3-C3H5)(CO)2L2], (L2 = dpm, dpe or 2py) and [W2Cl3(η3-C3H5)2(CO)4]− respectively. Under forcing conditions the nitrile complexes react with ditertiary phosphines to give low yields of the tungsten(0) derivatives cis-[W(CO)2(L2)2]. The solution ionization of [WCl(η3-C3H5)(CO)2(MeCN)2] to [W(η3-C3H5)(CO)2(MeCN)3+[W2Cl3(η3-C3H5)2(CO)4]− and free nitrile is slight compared with the molybdenum analoque.

The complexes previously reported to be the halogen bridged dimers [MoX(CO)2(η3-C3H5)(MeCN)]2, where X = Cl or Br, have been shown to be [Mo(CO)2(η3-C3H5)(MeCN)3]+[Mo2X3(CO)4(η3-C3H5)2]− in both the solid and solution states. Crystals of the chloro complex grown from benzene contain a solvent molecule and are monoclinic, space group P21/a with cell dimensions a = 16.352(11), b = 13.233(10), c = 16.067(12) A, β = 97.5(1)°, Z = 4. 2265 independent reflections above background have been measured using a twinned crystal on a diffractometer and refined to R 0.095 using full-matrix least squares. In the cation [Mo(CO)2(η3C3H5)(MeCN)3]+, the metal geometry is best considered as an octahedron with the allyl group [MoC 2.25(4)−2.36(5) A] occcupying one site and together with two carbonyl groups [MoC 1.99(4), 1.94(4) A] forming a fac arrangement. The three MeCN groups [MoN 2.22(3), 2.19(3), 2.19(3) A] complete the coordination sphere. In the anion [Mo2Cl3(η3-C3H5)2(CO)4]−, the two independent molybdenum atoms are each bonded to an allyl group [MoC 2.23(4)−2.38(4) A] and two carbonyl groups [1.90(4)−1.95(4) A] in a fac-arrangement. The two metal atoms are bridged by three chlorine atoms [MoCl(trans to allyl)2.52(1) A; MoCl(trans to carbonyl) 2.58(1)−2.62(1) A]. Cations, anions and solvent benzene molecules are separated by the usual van der Waals contacts.