Bacterial Catabolism of Biphenyls: Synthesis and Evaluation of Analogues

A series of alkylated 2,3‐dihydroxybiphenyls has been prepared on the gram scale by using an effective Directed ortho Metalation–Suzuki–Miyaura cross‐coupling strategy. These compounds have been used to investigate the substrate specificity of the meta‐cleavage dioxygenase BphC, a key enzyme in the microbial catabolism of biphenyl. Isolation and characterization of the meta‐cleavage products will allow further study of related processes, including the catabolism of lignin‐derived biphenyls.     

A case of conflicts in conservation: Two trenches or a three-dimensional complexity?

Conflicts over conservation are often regarded as dichotomies of diametrical opposites. When national parks are established in Norway, two stereotypes can be sketched: (1) the ecocentric position valuing 'pure, authentic nature', relying on the national government as the only acceptable decision and management level; and (2) a more anthropocentric position valuing cultural landscape elements and certain traditional and future uses of the area, favouring local management. A conflict over restoring a firing range to a state of 'authentic nature' for future designation as a national park is examined. The case has raised comprehensive local debate. It is asked whether the relevant actors should be seen as situated in the stereotypes, or whether a more complex three-dimensional picture would provide a better interpretation.     

Coating of LaCoO3 thin film with sol-gel dip coating method

LaCoO3 thin film was coated on Al2O3 single crystal by sol-gel route. Appropriate composition of precursors, chelating agents and the solvent put together into a flask and magnetically stirred on a magnetic stirrer. After having the red transparent solution, it was stirred for 12 hours before coating. Ultrasonically cleaned substrate is dipped into the solution and taken immediately into vertical furnace which is preheated at 550 degrees C. A dense amorphous film is coated on the substrate. Fired amorphous films are annealed at temperature between 900 degrees C and 1000 degrees C for 20 minutes in the air. Then coated film was characterized by means of XRD, AFM, and SEM. Conductivity of the film was measured to be -0.1819 for 881 degrees C for the log sigma value by assuming the thickness as     

Inventory on the dietary assessment tools available and needed in africa: a prerequisite for setting up a common methodological research infrastructure for nutritional surveillance,research, and prevention of diet-related non-communicable diseases

Objective: To carry out an inventory on the availability, challenges, and needs of dietary assessment (DA) methods in Africa as a pre-requisite to provide evidence, and set directions (strategies) for implementing common dietary methods and support web-research infrastructure across countries. Methods: The inventory was performed within the framework of the “Africa's Study on Physical Activity and Dietary Assessment Methods” (AS-PADAM) project. It involves international institutional and African networks. An inventory questionnaire was developed and disseminated through the networks. Eighteen countries responded to the dietary inventory questionnaire. Results: Various DA tools were reported in Africa; 24-Hour Dietary Recall and Food Frequency Questionnaire were the most commonly used tools. Few tools were validated and tested for reliability. Face-to-face interview was the common method of administration. No computerized software or other new (web) technologies were reported. No tools were standardized across countries. Conclusions: The lack of comparable DA methods across represented countries is a major obstacle to implement comprehensive and joint nutrition-related programmes for surveillance, programme evaluation, research, and prevention. There is a need to develop new or adapt existing DA methods across countries by employing related research infrastructure that has been validated and standardized in other settings, with the view to standardizing methods for wider use.     

Reverse prenyltransferase in the biosynthesis of fumigaclavine C in Aspergillus fumigatus: gene expression, purification, and characterization of fumigaclavine C synthase FGAPT1

A putative prenyltransferase gene-fgaPT1-has been identified in the biosynthetic gene cluster of fumigaclavines in Aspergillus fumigatus AF293. The gene was cloned and overexpressed in Escherichia coli, and the His6-fusion FgaPT1 was purified to near homogeneity and characterized biochemically. The enzyme was found to convert fumigaclavine A into fumigaclavine C by attaching a dimethylallyl moiety to C-2 of the indole nucleus in a "reverse" manner, that is, by connection of C-3 of the dimethylallyl moiety to an aromatic nucleus. FgaPT1 is a soluble, dimeric protein with a subunit size of 50 kDa. K m(app) values for fumigaclavine A and dimethylallyl diphosphate were determined to be 6 and 13 microM, respectively, while the turnover number was 0.8 s(-1). Metal ions such as Mg2+ and Ca2+ are not essential for the enzymatic activity. FgaPT1 showed relatively strict substrate specificity towards fumigaclavine A, with only dimethylallyl diphosphate being accepted as a donor under our conditions. FgaPT1 is the first reverse prenyltransferase from fungi to have been purified and characterized in homogenous form after heterologous overproduction. Surprisingly, it shows very low sequence similarity to the recently identified prenyltransferase LtxC from cyanobacteria, which also catalyzes the reverse prenylation of an indole nucleus.     

Hydrophilic and hydrophobic materials and their applications

Wettability of a material’s surface plays a significant role in how fluids interact with such surfaces. Wetting behavior is universal but can vary depending on the chemical nature of the solid and liquid phases. Plants and animals adapt to their environment by having evolved special properties. These properties are such as hydrophilic and hydrophobic. Hydrophilic surface has a strong affinity to water and spreading of water on such surface is preferred. The degree of hydrophilicity of the substance can be measured by measuring the contact angle between the liquid and solid phases. Hydrophobic materials are known as non-polar materials with a low affinity to water, which makes them water repelling. A contact angle of less than 90° indicates hydrophilic interaction where as an angle greater than 90° indicates a hydrophobic interaction. More recently, superwetting such as superhydrophilicity has been receiving an increased focus in the literature due to its potential significance. Superhydrophilic surface has a contact angle of less than 5°.

The fabrication of hydrophilic materials can be carried out in two main ways: depositing molecules on surfaces or modification of surface chemistry. Both methods have been successful historically in achieving their intended purposes. Hydrophobic and superhydrophobic materials can be produced with many fabrication methods such as layer-by-layer assembly, laser process, the solution-immersion method, sol-gen techniques, chemical etching, and Hummer’s method.

The applications of such an important property are significant. For example, hydrophilic surfaces can be used in anti-fogging applications, biomedical, filtration, heat pipes, and many others. Hydrophobic and superhydrophobic materials have been successfully applied in many sectors, such as: (I) the removal of petroleum from aqueous solutions, (II) applied to plastic, ceramics, and mesh to contribute to the oil removal from aqueous solutions, (III) hydrophobic layers have a strong self-cleaning effect on plastics, heat pipes, metals, textiles, glass, paints, and electronics, (IV) hydrophobic layers improve the anti-freezing behavior of heat pipes which prevents unwanted build-up and (V) they function as a water and dust protecting coat on electronics.

The presence of this property is historic but there is still a huge potential for development for its applications in many sectors such as water treatment, heat transfer applications, biomedical devices, and many more.