Systematic Chemoenzymatic Synthesis of O-Sulfated Sialyl Lewis x Antigens.

O-Sulfated sialyl Lewis x antigens play important roles in nature. However, due to their structural complexity, they are not readily accessible by either chemical or enzymatic synthetic processes. Taking advantage of a bacterial sialyltransferase mutant that can catalyze the transfer of different sialic acid forms from the corresponding sugar nucleotide donors to Lewis x antigens which are fucosylated glycans as well as an efficient one-pot multienzyme (OPME) sialylation system, O-sulfated sialyl Lewis x antigens containing different sialic acid forms and O-sulfation at different locations were systematically synthesized by chemoenzymatic methods

Regulation of AQP0 water permeability is enhanced by cooperativity.

Aquaporin 0 (AQP0), essential for lens clarity, is a tetrameric protein composed of four identical monomers, each of which has its own water pore. The water permeability of AQP0 expressed in Xenopus laevis oocytes can be approximately doubled by changes in calcium concentration or pH. Although each monomer pore functions as a water channel, under certain conditions the pores act cooperatively. In other words, the tetramer is the functional unit. In this paper, we show that changes in external pH and calcium can induce an increase in water permeability that exhibits either a positive cooperativity switch-like increase in water permeability or an increase in water permeability in which each monomer acts independently and additively. Because the concentrations of calcium and hydrogen ions increase toward the center of the lens, a concentration signal could trigger a regulatory change in AQP0 water permeability. It thus seems plausible that the cooperative modes of water permeability regulation by AQP0 tetramers mediated by decreased pH and elevated calcium are the physiologically important ones in the living lens

Fluorescent Labeling Technique and DNA Amplification By The Polymerase Chain Reaction for the Detection of Human Malaria Parasites.

The polymerase chain reaction (PCR) and fluorescence staining based diagnosis of Malaria infection was attempted. 187 samples in two groups: 135 and 52 patients Attending the Malaria Clinic (preventive Medicine and Al-Ain Hospital, UAE) were Collected Two PCR systems; using small subunit ribosomal RNA (ssrRNA) based primers And merozoite surface antigen (MSP) based primers were assessed, taking the Giemsa Stain as the reference test. The re sults of PCR using the merozoite surface antigen (MSP) primers specific for Pfalciparum, proved to be specific and accurate. These results were analyzed by agarose gel electrophoresis (AGE) and polyacrylamide gel electrophoresis (page) stained with Ethidium bromide and /or silver nitrate, which increases, detect ion sensitivity. The accuracy of the PCR could be improved by nested p riming. For the ssrRNA PCR system, the primers were not found to be specific for the different malaria species since ribosomal genes have a high degree of homology between different species. Fluorescent staining showed a great promise in detecting the different malaria species and Stages, but only acridness orange could be used routinely. It was concluded that PCR testing proved to be of a great value in diagnosing Malaria when appropriate primers are available. It could be used successfully in detection Of malaria in epidemiological surveys. Fluor chrome staining could be further improved But could not replace Giemsa staining

Group invariance principles for causal generative models

The postulate of independence of cause and mechanism (ICM) has recently led to several new causal discovery algorithms. The interpretation of independence and the way it is utilized, however, varies across these methods. Our aim in this paper is to propose a group theoretic framework for ICM to unify and generalize these approaches. In our setting, the cause-mechanism relationship is assessed by comparing it against a null hypothesis through the application of random generic group transformations. We show that the group theoretic view provides a very general tool to study the structure of data generating mechanisms with direct applications to machine learning.Comment: 16 pages, 6 figure

Efficient routes to racemic and enantiomerically pure (S)-BINOL diesters

A systematic study for esterification procedures to the synthesis of BINOL diesters is described. Reaction conditions with TFAA and 85% H3PO4 were selected as the best procedure to prepare enantiomerically pure (S)-BINOL diesters VIII to XI with almost quantitative yields and very low reaction times.Fil: Costantino, Andrea Rosana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Ocampo, Romina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Montiel Schneider, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Fernandez, Gustavo Adrian. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; ArgentinaFil: Koll, Liliana Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Mandolesi, Sandra Delia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur. Fundacion de la Universidad Nacional del Sur; Argentin

The N.A.C.A. Combustion Chamber Gas-sampling Valve and Some Preliminary Test Results

A gas sampling valve of the inertia-operated type was designed for procuring samples of the gases in the combustion chamber of internal combustion engines at identical points in successive cycles so that the analysis of the gas samples thus procured may aid in the study of the process of combustion. The operation of the valve is described. The valve was used to investigate the CO2 content of gases taken from the quiescent combustion chamber of a high speed compression-ignition engine when operating with two different multiple-orifice fuel injection nozzles. An analysis of the gas samples thus obtained shows that the state of quiescence in the combustion chamber is maintained during the combustion of the fuel

Bioinspired bola-type peptide dendrimers inhibit proliferation and invasiveness of glioblastoma cells in a manner dependent on their structure and amphipathic properties

(1) Background: Natural peptides supporting the innate immune system studied at the functional and mechanistic level are a rich source of innovative compounds for application in human therapy. Increasing evidence indicates that apart from antimicrobial activity, some of them exhibit selective cytotoxicity towards tumor cells. Their cationic, amphipathic structure enables interactions with the negatively-charged membranes of microbial or malignant cells. It can be modeled in 3D by application of dendrimer chemistry. (2) Methods: Here we presented design principles, synthesis and bioactivity of branched peptides constructed from ornithine (Orn) assembled as proline (Pro)- or histidine (His)-rich dendrons and dendrimers of the bola structure. The impact of the structure and amphipathic properties of dendrons/dendrimers on two glioblastoma cell lines U87 and T98G was studied with the application of proliferation, apoptosis and cell migration assays. Cell morphology/cytoskeleton architecture was visualized by immunofluorescence microscopy. (3) Results: Dimerization of dendrons into bola dendrimers enhanced their bioactivity. Pro- and His-functionalized bola dendrimers displayed cytostatic activity, even though differences in the responsiveness of U87 and T98G cells to these compounds indicate that their bioactivity depends not only on multiple positive charge and amphipathic structure but also on cellular phenotype. (4) Conclusion: Ornithine dendrons/dendrimers represent a group of promising anti-tumor agents and the potential tools to study interrelations between drug bioactivity, its chemical properties and tumor cells’ phenotype

Structured Finance Influence on Financial Market Stability – Evaluation of Current Regulatory Developments

In 2007 the world faced one of the biggest financial crises ever. It was the third important financial crisis in the last 12 years. Spillovers to the real economy and moral hazard behaviour of carpetbaggers resulted in enormous pressure on worldwide political institutions to approve a more rigorous regulation on financial institutions and to predict financial crises via early warning systems. We analyzed the performance of structured finance ratings and structured finance issuance/outstanding to detect the main shortcomings of the subprime crisis. Afterwards, we explain the behaviour of market participants with theoretical models and a survey of institutions involved in securitization. With the conclusions of this analysis we evaluate the EU regulation on credit rating agencies and current Basel II enhancements. Finally we can determine that most regulatory enhancements are in accordance with our analyzed shortcomings. Some approaches like the introduction of a leverage ratio are counterproductive and a danger for worldwide economic growth.Structured Finance; Ratings; Regulation; Subprime Crisis; Basel II; Leverage Ratio