Immunogenicity and Efficacy of Liposome-encapsulated Influenza Split Vaccine in BALB/c Mice

The cellular immunity of current influenza split vaccine is relatively low. It is necessary to develop a novel vaccine to improve the cellular immunity. Thes of this study prepared liposome-encapsulated influenza split vaccine and tested it in BALB/c mice. The mice were immunized once with 4 μg of haemagglutinin of monovalent A/New Caledonia/20/99(H1N1) encapsulated with liposomes or the split virus vaccine only through intrastomach injection. In a comparative study, it was observed that the liposome-encapsulated vaccine elicited a higher neutralizing antibody response, more effectively stimulated spleen cell proliferation, increased cell subsets like CD4 and CD4 /CD8 , and triggered IL-4 and IFN-γ production.     

Syntheses and Structures of Two New Oxalate-bridged Transition-metal Supramolecular Polymers of [ M （ 2-NH2 py） 2 （ox）

Two new supramoleeular polymers [ M （2-NH2 py）2 （ox） ] [ M = Co （1）, Ni （2） ; 2-NH2py = 2-aminopyridine; ox = oxalate ] were hydrothermally synthesized and characterized by elemental analyses, IR and single-crystal X-ray diffraction analyses. The isomorphic compounds 1 and 2 both possess one-dimensional zigzag chain structures, which are composed of [ M （2-NH2 py）2 ]^2＋ units bridged by tetradentate oxalate ligands to form three-dimensional supramolecular network v/a the C-H…O hydrogen bonds and π-π stacking interactions. Compound 1 displays antiferromagnetie interaction.     

Metal-induced B-H activation: addition of methyl acetylene carboxylates to Cp*Rh-, Cp*Ir-, (p-cymene)Ru-, and (p-cymene)Os half-sandwich complexes containing the chelating 1,2-dicarba-closo-dodecaborane-1,2-dithiolate ligand

The reactions of the 16e half-sandwich complexes [Cp*M[S2C2(B10)H10)]] (1: M=Rh; 2: M = Ir) and [eta6-(4-isopropyltoluene)M[S2C2(B10H10)] (3: M=Ru; 4: M=Os) with both methyl acetylene monocarboxylate and dimethyl acetylene dicarboxylate were studied in order to obtain more evidence for B-H activation, ortho-metalation, and B(3,6)-substitution of the carborane cluster. In the case of rhodium, the reaction of 1 with methyl acetylene monocarboxylate led to new complexes after twofold insertion into one of the Rh-S bonds (7), and twofold insertion together with B-substitution at the carborane cage (8). In the case of iridium, the reactions of 2 with methyl acetylene monocarboxylate gave two geometrical isomers 10 and 11, in which the alkyne is inserted into one of the Ir-S bonds, followed by hydrogen transfer from the carborane via the metal to the former alkyne and formation of an Ir-B bond. Only one type each (12 and 13) of these isomers was obtained from the reactions of the ruthenium and osmium half-sandwich complexes 3 and 4. The 16e starting materials 1-4 reacted with dimethyl acetylene dicarboxylate at room temperature to give the complexes 14-17, respectively, which are formed by addition of the C=C bond to the metal center and insertion into one of the metal-sulfur bonds. The proposed structures in solution were deduced from NMR data (1H, 11B, 13C, 103Rh NMR), and X-ray structural analyses were carried out for the rhodium complexes 7 and 8.     

Organophosphonotungstic HPA of Keggin Type with Sulfo,Taurine and Glycine Substituted Ethylphosphonic Acids as the Coordinate Center

Recent years, heteropoly acids (HPA)and their derivatives have received current attention due to their potential applications in analytical chemistry, catalysis, material sciences and medicine1-2. Usually, the core or coordinate center for most of the heteropoly compounds (HPC) are inorganic acids such as H3PO4, H3SiO3 etc. Although HPC with organophosphonic acids as coordinate center have been confirmed about 15 years ago, in which the molar ratio x: m for most of the heteropoly anion…     

Packing structure and self-heating in capillary electrochromatography

The origin of bubble formation during operation of capillary electrochromatography (CEC) has been an issue of debate. Ohmic heating resulted from current passed through a packed column was proposed as the primary cause. However, this explanation has been questioned on the ground that the current measured in CEC is much lower than that measured with open-tubular separation systems where no bubble formation occurs. To resolve this issue, we carried out a theoretical study correlating self-heating of the electrolyte with packing structure of the column. We used a bundle of capillary tubes, a bundle of two types of capillary tubes and two bundles of capillary tubes connected serially to model, respectively, the flow channels in the column of non-porous particles, in the column of porous particles and in the column of various packing densities. The results from this study indicate that, for columns of homogeneous packing density, the heat output is indeed smaller than that in open-tubular columns of the same dimensions. In this case, the self-heating cannot be a key factor responsible for the bubble formation in CEC. However, for columns of heterogeneous packing density, a large excess of heat release may be produced in column sections of high packing density and, in turn, over-heating in such sections may become the primary cause for the formation of bubbles. It follows from this study that preparation of columns of homogeneous packing structure is essential to obtain reproducible and bubble-free CEC systems.     

A computational study on the mechanism for the chemical fixation of nitric oxide leading to 1,2,3-oxadiazole 3-oxide

The chemical fixation of nitric oxide (NO) reacting with alkynyllithium to produce 5-methyl-3-oxide-1,2,3-oxadiazole has been investigated by using ab initio (U)MP2 and DFT/(U)B3LYP methods. The solvent effect was assessed using the combination of microsolvation model with explicit THF ligands on lithium and continuum solvent model based on the SCRF/CPCM method at the (U)B3LYP/6-31G* level. Our results reveal that the overall reaction is stepwise and considered to include two processes. In process 1, the nitrogen atom in nitric oxide at first attacks the C(1) atom in alkynyllithium to afford the intermediate 5. In process 2, after another nitric oxide reacted with the intermediate 5 to produce 8a, we found that two pathways are involved. For path 1, the O(2) atom at first attacks the C(2) atom to form a five-membered ring geometry, and then lithium can rotate around the N(1)-O(1) bond, leading to the product 5-methyl-3-oxide-1,2,3-oxadiazole followed addition of water. However, for path 2, lithium atom rotates first around the N(1)-O(1) bond, and then the product 5-methyl-3-oxide-1,2,3-oxadiazole is also generated by addition of water. Our calculations indicate that path 1 is more favorable than path 2 in the gas phase, while both of them exist possibly in THF solvent. The overall reaction is exothermic.     

Preparation and evaluation of a molecularly imprinted sol-gel material for on-line solid-phase extraction coupled with high performance liquid chromatography for the determination of trace pentachlorophenol in water samples

A highly selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for on-line solid-phase extraction-HPLC determination of trace pentachlorophenol (PCP) in water samples. The PCP-imprinted amino-functionalized silica sorbent was characterized by FT-IR, SEM, nitrogen adsorption and the static adsorption experiments. The imprinted functionalized silica gel sorbent exhibited high selectivity and offered a fast kinetics for the adsorption and desorption of PCP. The prepared sorbent was shown to be promising for on-line solid-phase extraction for HPLC determination of trace levels of PCP in environmental samples. With a sample loading flow rate of 5 ml min(-1) for 2 min, an enhancement factor of 670 and a detection limit (S/N = 3) of 6 ng l(-1) were achieved at a sample throughput of five samples h(-1). The precision (RSD) for nine replicate on-line sorbent extractions of 10 microgl(-1) PCP was 3.8%. The sorbent also offered good linearity (r = 0.9997) for on-line solid-phase extraction of trace levels of PCP. The method was applied to the determination of PCP in local lake water, river water and wastewater samples.     

Highly selective oxidation of amines to imines by Mn2O3 catalyst under eco-friendly conditions

Mn₂O₃ calcined at 450 ℃ by a simple template-free oxalate route gave 96.2% selectivity of imine at 100% conversion of benzylamine. The high selectivity of the imines clearly depended on the Mn³⁺/Mn⁴⁺ ratio. The probable reaction pathway for amines oxidation catalyzed by manganese oxides was proposed for the first time. This catalytic process was carried out under milder conditions, no base additives, and air as the only oxidant.     

Investigation on the regioselectivities of intramolecular oxidation of unactivated C-H bonds by dioxiranes generated in situ

We found that dioxiranes generated in situ from ketones 1-6 and Oxone underwent intramolecular oxidation of unactivated C-H bonds at delta sites of ketones to yield tetrahydropyrans. From the trans/cis ratio of oxidation products 1a and 2a as well as the retention of the configuration at the delta site of ketone 5, we proposed that the oxidation reaction proceeds through a concerted pathway under a spiro transition state. The intramolecular oxidation of ketone 6 showed the preference for a tertiary delta C-H bond over a secondary one. This intramolecular oxidation method can be extended to the oxidation of the tertiary gamma' C-H bond of ketones 9 and 10. For ketone 11 with two delta C-H bonds and one gamma' C-H bond linked respectively by a sp(3) hydrocarbon tether and a sp(2) ester tether, the oxidation took place exclusively at the delta C-H bonds. Finally, by introducing proper tethers, regioselective hydroxylation of steroid ketones 12-14 have been achieved at the C-17, C-16, C-3, and C-5 positions.     

Separation of peptides by pressurized capillary electrochromatography

A pressurized electrochromatography (pCEC) instrument with gradient capability was used in this work for separation of peptides. Three separation modes, namely, pCEC, high-performance liquid chromatography and capillary electrophoresiscan be carried out with the instrument. In pCEC mode, the mobile phase is driven by both electroosmotic flow and pressurized flow, facilitating fine-tuning in selectivity of neutral and charged species. A continuous gradient elution can be carried out conveniently on this instrument, which demonstrates that it is more powerful than isocratic pCEC for separation of complicated samples. The effects of applied voltage, supplementary pressure and ion-pairing agents on separation of peptides in gradient pCEC were investigated. The effects of flow-rate of the pump and the volume of the mixer on resolution were also evaluated.