Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process

In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4‐aminothiophenol (4‐ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm⁻², was synthesized.

     

Heavy sterile neutrinos and supernova explosions

We consider sterile neutrinos with rest masses 0.2 GeV and with vacuum flavor mixing angles θ²>10⁻⁸ for mixing with τ-neutrinos, or 10⁻⁸<θ²<10⁻⁷ for mixing with muon neutrinos. Such sterile neutrinos could augment core collapse supernova shock energies by enhancing energy transport from the core to the vicinity of the shock front. The decay of these neutrinos could produce a flux of very energetic active neutrinos, detectable by future neutrino observations from galactic supernova. The relevant range of sterile neutrino masses and mixing angles can be probed in future laboratory experiments.     

Hypothermic renal preservation with a sucrose/ polyethylene glycol solution in a rabbit renal transplant model

Renal preservation at for 24 hours at hypothermia was studied in a rabbit model after flush cooling with sucrose-based solution (SBS), compared with a standard preservation solution (in this case, Marshall's Hypertonic Citrate solution - HCA). Polyethylene glycol supplementation to SBS (SBS-PEG) was also investigated. Renal function was measured by plasma creatinine assays during 1 months post transplantation, and pathology of the explanted kidneys was undertaken. Results showed that survival at 28 days was similar in all groups, (HCA - 3 out of 6; SBS - 2 out of 5; SBS-PEG - 3 out of 5), and there were no differences in recovery of plasma creatinine values. Histopathological evaluation of the grafts indicated that SBS preservation resulted in more severe damage after transplantation (P less than 0.05 in both corticomedullary region and medulla compared to HCA), whilst addition of PEG reduced the damage score to that seen with HCA. SBS can be used as a simple, inexpensive preservation solution for kidney cold storage provided that PEG is used as an additional colloid.     

The X-Ray Structures of Sulfoxides

Abstract  We have structurally characterized and investigated a range of sulfoxide compounds containing aryl and alkyl substituents. Compounds 1 and 3–6 all crystallize in an orthorhombic space group, where compounds 2 and 7 crystallize in a monoclinic space group. The unit cell parameters of the compounds are as follows: 1 (Fdd2), a = 17.653(5) ?, b = 53.153(14) ?, and c = 10.071(3) ?; 2 (P2 ₁ /c), a = 7.894(13) ?, b = 5.653(10) ?, and c = 27.02(5) ?, β = 97.347(15)°; 3 (P2 ₁ 2 ₁ 2 ₁ ), a = 5.7569(6) ?, b = 12.2139(12) ?, and c = 17.5974(18) ?; 4 (Pca2 ₁ ), a = 8.256(4) ?, b = 5.470(3) ?, and c = 23.995(13) ?; 5 (P2 ₁ 2 ₁ 2 ₁ ), a = 5.848(4) ?, b = 7.568(5) ?, and c = 27.650(17) ?; 6 (Pbca), a = 10.0569(15) ?, b = 9.9403(16) ?, and c = 17.843(3) ?; and 7 (Pc), a = 13.217(4) ?, b = 5.3766(14) ?, and c = 8.370(2) ?, β = 90.673(6)°. The S=O bond distances in these compounds range from 1.489(7) to 1.515(8) ?. In all seven structures, the O(1)–S–C bond angles vary from 105.1(4) to 111.7(30)° and the C(1)–S(1)–C(11) bond angles range from 94.1(4) to 100.56(12)°. The compounds contain unique intra- and intermolecular interactions depending on the groups attached to the sulfoxide moiety. The polarity of the sulfoxide bond in these compounds allows for intramolecular S···O interactions to occur. When the sulfur is bound to alkyl groups, there tends to be a shorter S···O intermolecular distance than when the sulfur is bound to aromatic substituents. Additionally, if the sulfur is flanked by an aryl group, the S–C bond distance is slightly shorter than if flanked by an alkyl group, suggesting a possible weak O···H_aryl intramolecular interaction, weak conjugation of the aromatic ring with the S–O bond or both. Furthermore, if the sulfur is flanked by an alkyl group, a CH₂ proton of S–CH₂–R can be properly oriented to participate in an intermolecular hydrogen bond with the sulfoxide oxygen of another molecule. Index Abstract  We have structurally characterized and investigated a range of sulfoxide compounds containing aryl and alkyl substituents that contain unique intra- and intermolecular interactions depending on the groups attached to the sulfoxide moiety.      

Temperature dependence of pressure broadening and shifts of acetylene at 1550 nm by He, Ne, and Ar

Pressure broadening and shift coefficients for the ν₁+ν₃ band of ¹²C₂H₂ have been measured for He, Ne, and Ar at a temperature of 195 K using high resolution diode laser spectroscopy. The pressure broadening and shifts follow patterns with rotational assignment that are similar to those at room temperature but are generally larger in magnitude. The change in magnitude is qualitatively described by assuming, for each transition, a constant cross section for pressure broadening or shifting. Better agreement may be obtained for pressure broadening coefficients by using empirically determined temperature exponents; better agreement still is obtained from close coupling calculations of the pressure broadening cross sections. PACS 33.70.Jg     

Fuzzification of linear systems of equalities and inequalities

Translated from Aktual'nye Voprosy Prikladnoi Matematiki, pp. 73–80, 1989.     

Dynamics of adsorbed polymer chains subjected to flow: The dumbbell model

The dumbbell model of an adsorbed polymer segment is analyzed in order to investigate the response of such segments to a velocity gradient imposed at the solid/liquid interface. It is demonstrated that exact expressions for the time-dependent moments of the distribution function describing the conformation can be obtained. Both a dangling end and an attached loop can be represented and several bulk properties of a polymer film subjected to flow are evaluated.     

EFFECTS OF PHASIC AND TONIC LIGHT INPUTS ON THE ORCADIAN ORGANIZATION OF THE SQUIRREL MONKEY

Abstract— The organization of the circadian timing system in Saimiri sciureus was probed using the phasic (abrupt transition) and tonic (continuous action) effects of light intensity. The behavior of the simultaneously monitored circadian rhythms of feeding behavior, colonic temperature, and urinary potassium excretion was studied in response to the phasic effects of (a) an abrupt 8-h phase delay in the light–dark (LD) cycle and (b) a series of non-24 h LD cycles ( T = 18 to 30 h). These studies demonstrated that the feeding and temperature rhythms were more tightly coupled to the light-dark cycle than was the rhythm of urinary potassium excretion. The tonic effects of constant levels of illumination confirmed this conclusion. In constant light, internal desynchronization spontaneously occurred in 25% of animals with the potassium rhythm exhibiting a period quite different from that of the feeding and colonic temperature rhythms. Thus, the response of the internal circadian timekeeping system to phasic and tonic light inputs shows that the system in this species comprises at least two potentially independent oscillators with differential light sensitivities.     

Manganese(II) chemistry of a new N3O-donor chelate ligand: synthesis, X-ray structures, and magnetic properties of solvent- and oxalate-bound complexes

The synthesis and characterization of a new N3O donor ligand N-benzyl-N-((6-pivaloylamido-2-pyridyl)methyl)-N-(2-pyridylmethyl)amine (bpppa) is reported. Treatment of bpppa with Mn(II)(ClO4)2.6H2O in acetonitrile solution yielded the mononuclear [(bpppa)Mn(CH3CN)(H2O)](ClO4)2 (1) which was characterized by X-ray crystallography, elemental analysis, IR spectroscopy, mass spectrometry, and a solution magnetic moment measurement. Admixture of equimolar equivalents of bpppa and Mn(II)(ClO4)2.6H2O in methanol solution, followed by addition of 0.5 or 1 equivalents of sodium oxalate, yielded the binuclear complex [{(bpppa)Mn}2([mu]-C2O4)](ClO4)2 (2), which was characterized by X-ray crystallography, elemental analysis, IR spectroscopy, mass spectrometry, and solid-state magnetic measurements. While 1 is mononuclear, the formation of the binuclear oxalate derivative indicates that use of the bpppa ligand does not enable isolation of a complex that is structurally relevant to a proposed 1:1 Mn(II)-oxalate adduct in the catalytic cycle of the oxalate degrading enzyme oxalate decarboxylase.