A rapid magnetizable solid phase radioimmunoassay kit for human placental lactogen

The radioimmunoessay of human placental lactogen (HPL) with separation of antibody bound and free hormone was achieved by the magnetizable solid phase coupled to antibody. The precision, accuracy, sensitivity and specificity of the method has been carefully checked in this study and the procedure of the assay was performed at room temperature. The above parameters were evaluated by recovery test (99%); within assays (4%), between assays (5%), sensitivity (0.04 g/ml) and there was no obvious cross reactivity with human growth hormone (hGH) and human chorionic gonadotropin (hCG).     

Investigation of the microstructure of micelles formed by hard-sphere chains interacting via size nonadditivity by discontinuous molecular dynamics simulation

Micelle formation by short nonadditive hard surfactant chains was investigated at different size ratios, reduced densities, and nonadditivity parameters using molecular dynamics simulation. It was found that spherical, cylindrical, lamellar, and reverse micelles can form in systems with different head, tail, and solvent characteristics. Hard-core surfactant chains composed of a head segment and three tail segments were simulated in a solvent of hard spheres. The formation of micelles was found to be a strong function of the packing fraction and nonadditivity parameter. Micelles were more stable at higher densities and larger nonadditivity parameters. At lower densities, micelles tended to break into small, dynamic globules.     

Modelling a Linker Mix‐and‐Match Approach for Controlling the Optical Excitation Gaps and Band Alignment of Zeolitic Imidazolate Frameworks

Tuning the electronic structure of metal–organic frameworks is the key to extending their functionality to the photocatalytic conversion of absorbed gases. Herein we discuss how the band edge positions in zeolitic imidazolate frameworks (ZIFs) can be tuned by mixing different imidazole‐based linkers within the same structure. We present the band alignment for a number of known and hypothetical Zn‐based ZIFs with respect to the vacuum level. Structures with a single type of linker exhibit relatively wide band gaps; however, by mixing linkers of a low‐lying conduction edge with linkers of a high‐lying valence edge, we can predict materials with ideal band positions for visible‐light water splitting and CO₂ reduction photocatalysis. By introducing copper in the tetrahedral position of the mixed‐linker ZIFs, it would be possible to increase both photo‐absorption and the electron–hole recombination times.     

Quantum and Classical Molecular Dynamics of Ionic Liquid Electrolytes for Na/Li‐based Batteries: Molecular Origins of the Conductivity Behavior

Compositional effects on the charge‐transport properties of electrolytes for batteries based on room‐temperature ionic liquids (RTILs) are well‐known. However, further understanding is required about the molecular origins of these effects, in particular regarding the replacement of Li by Na. In this work, we investigate the use of RTILs in batteries, by means of both classical molecular dynamics (MD), which provides information about structure and molecular transport, and ab initio molecular dynamics (AIMD), which provides information about structure. The focus has been placed on the effect of adding either Na⁺ or Li⁺ to 1‐methyl‐1‐butyl‐pyrrolidinium [C₄PYR]⁺ bis(trifluoromethanesulfonyl)imide [Tf₂N]^?. Radial distribution functions show excellent agreement between MD and AIMD, which ensures the validity of the force fields used in the MD. This is corroborated by the MD results for the density, the diffusion coefficients, and the total conductivity of the electrolytes, which reproduce remarkably well the experimental observations for all studied Na/Li concentrations. By extracting partial conductivities, it is demonstrated that the main contribution to the conductivity is that of [C₄PYR]⁺ and [Tf₂N]^?. However, addition of Na⁺/Li⁺, although not significant on its own, produces a dramatic decrease in the partial conductivities of the RTIL ions. The origin of this indirect effect can be traced to the modification of the microscopic structure of the liquid as observed from the radial distribution functions, owing to the formation of [Na(Tf₂N)_n]^(n?1)? and [Li(Tf₂N)_n]^(n?1)? clusters at high concentrations. This formation hinders the motion of the large ions, hence reducing the total conductivity. We demonstrate that this clustering effect is common to both Li and Na, showing that both ions behave in a similar manner at a microscopic level in spite of their distinct ionic radii. This is an interesting finding for extending Li‐ion and Li‐air technologies to their potentially cheaper Na‐based counterparts.     

Mathematics for chromatography. Part I: Concentration distributions and their moments

Several distributions of interest in chromatography were studied. In each case, the moments up to 4th moment were evaluated and the skew and the excess were deduced. The distributions studied in this article are the normal, continuous Poisson, discrete Poisson, exponentially modified normal, and exponentially modified Poisson distributions.     

Design and synthesis of multi-component 18 pi annulenic fluorofullerene ensembles suitable for donor-acceptor applications

A series of trannulene (all-trans annulene) derivatives of [60]fullerene have been prepared by reacting C(60)F(18) with methanetricarboxylate esters that incorporate a range of photoactive functions. All the compounds have the intense emerald-green colour of fullerene trannulenes, characterised by strong bands at ca. 612 and 667 nm. Single crystal X-ray studies show that the packing varies with the nature of the addend, attributable to differing steric effects. UV/vis absorption spectra display transitions of the respective fullerene and addend models, indicating absence of electronic interactions between them in the ground state. These now provide an extensive series for testing photoactive (light-harvesting) properties, with the exceptional properties of having strong visible light absorption. Their exceptional stability is attributed to the 18[small pi] aromatic circuit, inability to undergo nucleophilic substitution without disrupting this circuit, and a curved cage region that is shielded to reagents by the three bulky addends.     

Effect of Support on Metathesis of n‐Decane: Drastic Improvement in Alkane Metathesis with WMe5 Linked to Silica–Alumina

[WMe₆] ( 1 ) supported on the surface of SiO₂–Al₂O₃₍₅₀₀₎ ( 2 ) has been extensively characterized by solid‐state NMR spectroscopy, elemental analysis, and gas quantification, which clearly reveal the formation of a mixture of monopodal and bipodal species with the migration of methyl from W to Al. The supported species SiO₂–Al₂O₃₍₅₀₀₎ ( 2 ) transformed at 120 °C into two types of carbynic centers, one of which is cationic and the other neutral. These species are very efficient for the metathesis of n‐decane. Comparison with already‐synthesized neutral bipodal tungsten indicates that the high increase in activity is due to the cationic character of the grafted tungsten.     

α-Li3InF6, a ternary fluoride with a new structure type

Reaction of anhydrous binary fluorides LiF and InF₃ in sealed platinum tube at the temperature gradient 680/670°C yields α-Li₃InF₆. This low-temperature form crystallizes in the space group P2₁/m with the cell dimensions a = 4.797(3) Å, b = 8.679(1) Å, c = 10.366(1) Å and β = 90.90(1)°. The framework is built from InF₆ and LiF₆ octahedra, beside [Li₂F₆] bitetrahedra. The b-axis seems to be the backbone in the structural features. Running along it, zigzag anionic chains , resulting from one—edge shared [Li₂F₁₀] groups and double files of single InF₆ octahedra sharing common corners with [Li₂F₆], create an approximately hexagonally packed framework in the plane (1 0 0). The antiferroelectric behaviour evident from dielectric studies is confirmed by the antiparallel displacements of In and Li atoms from octahedral centres. This structure is mainly featured by the disorder observed in the lightest atoms. These atoms, which exhibit two kinds of environments, have been refined as two partially occupied sites for the tetrahedral one. Within the Li₃MF₆ compounds (M: trivalent or 3d element), this new structure reveals unexpected structural features, inducing its ferroic properties.