Solid-Phase Synthesis of a Fragment of the Capsular Polysaccharide of Haemophilus Influenzae Type B Using H-Phosphonate Intermediates

Abstract

A pentameric fragment of the capsular polysaccharide of Haemophilus influenzae type b, containing a linker group, was synthesized by a simple solid-phase procedure. Cross-linked polystyrene was used as a solid phase, and a benzyl-protected ribosylribitol H-phosphonate was used as monomer. A non-promoted glycosidation reaction was used for preparation of the ribosylribitol monomer.     

Der Gaskomplex FeGaCl6 und seine Mitwirkung beim chemischen Transport von Fe2O3

The Gas Complex FeGaCl₆ and its Participation on the Chemical Transport of Fe₂O₃ The chemical transport of Fe₂O₃ by means of HCl in the temperature gradient 600 → 700 K is promoted by the addition of GaCl₃ as a complex forming agent. The formation of gaseous FeGaCl₆ causes the transport of Fe₂O₃ into the hot temperature region. The importance of the gas complex is discussed thermodynamically and verified experimentally.     

A computerised, unbiased method for epithelial measurement

OBJECTIVE: To develop and evaluate a standardised method for unbiased measurements of epithelial thickness taking the variability of the dermal papillae in consideration. METHODS: A computer-assisted measurement program suitable for haematoxylin and eosin routine stained specimens has been developed. RESULTS: The developed program was designed to measure four different distance parameters, taking the number, height and width of dermal papillae into account. The measurement program gave very accurate results compared with manual measurements. The measurement results can be presented as tables or star graphs, and the results can be further processed by multivariate analysis. CONCLUSION: The computer-assisted measurement program is considered to be a valuable and reliable tool for measurements of epithelial thickness, irrespectively of the variability of the epithelial morphology. Since length, size and number of the papillae may change with certain pathological conditions, age and also under hormonal influence, this method can be a helpful diagnostic tool.     

The Electrochemical Stability of Starch Carbon as an Important Property in the Construction of a Lithium-Ion Cell

This paper shows use of starch-based carbon (CSC) and graphene as the anode electrode for lithium-ion cell. To describe electrochemical stability of the half-cell system and kinetic parameters of charging process in different temperatures, electrochemical impedance spectroscopy (EIS) measurement was adopted. It has been shown that smaller resistances are observed for CSC. Additionally, Bode plots show high electrochemical stability at higher temperatures. The activation energy for the SEI (solid–electrolyte interface) layer, charge transfer, and electrolyte were in the ranges of 24.06–25.33, 68.18–118.55, and 13.84–15.22 kJ mol⁻¹, respectively. Moreover, the activation energy of most processes is smaller for CSC, which means that this electrode could serve as an eco-friendly biodegradable lithium-ion cell element.     

From Damage to Delamination

Delamination models are derived as the limits of models for partial isotropic volume damage via dimension reduction. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Evaluation of the specific mass shift and field shift in the alkaline-earth Sr atom

Vinti's expression for the Specific mass shift, determined as a sum over Slater integrals, has been used in a first-order perturbation treatment of alkaline-earth atoms. The Specific mass shift and Field shift have been evaluated for a number of transitions in the Sr atom. Mixing of the main configuration with one or two excited configurations has been taken into account in the levels involved in some of the transitions. The orbitals were generated in a potential, with adjustable radial scaling parameters, represented by an analytic expression with an infinite radius of convergence. The present results are compared, where possible, with results of other theoretical calculations and with experimental data.     

The chemical transport of molybdenum and tungsten and of their dioxides and sulfides

Experiments have been made and an extensive thermodynamic discussion has taken place concerning the chemical transport of Mo, W, MoO₂, WO₂, MoS₂ and WS₂ in the presence of iodine. Efforts have been made to find the species via which Mo and W can migrate within the gas phase.Results: In each case the transport proceeds via the oxide iodides MoO₂J₂ and WO₂J₂ respectively, as already known for the dioxides. Thus the chemical transport of Mo, W, MoS₂ and WS₂ needs not only J₂ but also H₂O, usually liberated from the wall of the quartz ampoule.By means of J₂ + H₂O, the metals can be transported into the high temperature region of the ampoule (e.g., 1050 → 1150°C), whereas the transport of the sulfides proceeds in the opposite direction (e.g., 900 → 700°C).For the sulfide-transport the influence of the ratio of the transport agents $\text{J}{}_2\text{H}{}_2\text{O}$ has been discussed.The water content of the quartz glass out of which the ampoules are made is an important source for water, influencing the reactions.The addition of graphite which considerably lowers the H₂O partial pressure prevents any transport of the metals or the sulfides, which proves that the use of J₂ alone as a transport agent is insufficient in these cases.The gaseous iodides MoJ_x and WJ_z are without any importance under the experimental conditions used for the transport of the metals, their dioxides and sulfides.The partial pressures of MoO₂(OH)₂ and WO₂(OH)₂ under the experimental conditions chosen may usually be neglected. But in the system $\text{MoO}{}_2\text{H}{}_2\text{O}$ the transport via MoO₂(OH)₂ (1000 → 800°C) has been observed.The synthesis of MoO₂ and WO₂, starting with the elements or with powder of metal and trioxide is promoted by the addition of J₂. The reaction steps involved are discussed.     

Die Bedeutung der Gasmolekeln MGa2Cl8, MGaCl5 und MCl2 (M = Ca,Cr, Fe,Co, Ni,Cu, Pd) beim chemischen Transport von MCl2,f mit GaCl3/Ga2Cl6

The Meaning of the Gas Molecules MGa₂Cl₈, MGaCl₅, and MCl₂ (M = Ca, Cr, Fe, Co, Ni, Cu, Pd) in the Chemical Transport of MCl_2,f, with GaCl₃/Ga₂Cl₆ On the reaction of MCl_2,s with GaCl₃ the vapor pressures of MGa₂Cl₈, MGaCl₅. MCl₂, Ga₂Cl₆, and GaCl₃ are found to exist above the solid phase. The temperature dependence of λ(M) = ΣP(M)/ΣP(Ga) is essential for the chemical transport of MCl_2,s. On variation of T a maximum of P(MGa₂Cl₈) is observed which originates from the dissociation reaction Ga₂Cl₆ = 2 GaCl₃ and which may lead in uncomplicated cases to a maximum of λ/T curve. Further increase in T results in a minimum of the λ/T dependence; its position is governed by the value of P(MCl₂) + P(MGaCl₅). In the range between maximum and minimum of λ/T MCl_2,s is transported into th high temperature region. Reduced stability of MGa₂Cl₈ and/or increased stability of MGaCl₅ resp. MCl_2,g may lead to a λ/T dependence without extrema. No transport of MCl₂ to the high temperature region may take place under these conditions. Experimental and calculated data are given for the reactions under consideration.     

Influence of Nanoscale Surface Topography and Chemistry on the Functional Behaviour of an Adsorbed Model Macromolecule

The functional behaviour of a model macromolecule (fibrinogen) adsorbed at the nanofabricated solid‐liquid interface was found to be strongly influenced by the local topographic structure of the interface. Protein molecules bound at topographically structured surfaces (either chemically homogeneous or heterogeneous 40‐nm diameter and 10‐nm deep pits) were found to bind platelets significantly faster than uncoated substrates whereas proteins bound to flat (R_a 1 nm) substrates were not. During the initial interaction, the chemistry of the underlying substrate apparently does not affect the macromolecules' functional behaviour.