30 research outputs found
Macroscopic transport by synthetic molecular machines
Nature uses molecular motors and machines in virtually every significant biological process, but demonstrating that simpler artificial structures operating through the same gross mechanisms can be interfaced with—and perform physical tasks in—the macroscopic world represents a significant hurdle for molecular nanotechnology. Here we describe a wholly synthetic molecular system that converts an external energy source (light) into biased brownian motion to transport a macroscopic cargo and do measurable work. The millimetre-scale directional transport of a liquid on a surface is achieved by using the biased brownian motion of stimuli-responsive rotaxanes (‘molecular shuttles’) to expose or conceal fluoroalkane residues and thereby modify surface tension. The collective operation of a monolayer of the molecular shuttles is sufficient to power the movement of a microlitre droplet of diiodomethane up a twelve-degree incline.
Whole blood gene expression profiling in preclinical and clinical cattle infected with atypical bovine spongiform encephalopathy
Prion diseases, such as bovine spongiform encephalopathies (BSE), are transmissible neurodegenerative disorders affecting humans and a wide variety of mammals. Variant Creutzfeldt-Jakob disease (vCJD), a prion disease in humans, has been linked to exposure to BSE prions. This classical BSE (cBSE) is now rapidly disappearing as a result of appropriate measures to control animal feeding. Besides cBSE, two atypical forms (named Hand L-type BSE) have recently been described in Europe, Japan, and North America. Here we describe the first wide-spectrum microarray analysis in whole blood of atypical BSEinfected cattle. Transcriptome changes in infected animals were analyzed prior to and after the onset of clinical signs. The microarray analysis revealed gene expression changes in blood prior to the appearance of the clinical signs and during the progression of the disease. A set of 32 differentially expressed genes was found to be in common between clinical and preclinical stages and showed a very similar expression pattern in the two phases. A 22-gene signature showed an oscillating pattern of expression, being differentially expressed in the preclinical stage and then going back to control levels in the symptomatic phase. One gene, SEL1L3, was downregulated during the progression of the disease. Most of the studies performed up to date utilized various tissues, which are not suitable for a rapid analysis of infected animals and patients. Our findings suggest the intriguing possibility to take advantage of whole blood RNA transcriptional profiling for the preclinical identification of prion infection. Further, this study highlighted several pathways, such as immune response and metabolism that may play an important role in peripheral prion pathogenesis. Finally, the gene expression changes identified in the present study may be further investigated as a fingerprint for monitoring the progression of disease and for developing targeted therapeutic interventions. \ua9 2016 Xerxa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Ethylene metabolism in Pisum sativum L. : Kinetic parameters, the effects of propylene, silver and carbon dioxide and comparison with other systems
The kinetic parameters of in vivo ethylene metabolism by seedlings of Pisum sativum L. cv. Alaska have been determined. The oxidation of ethylene to CO2, (Ox) and the incorporation of ethylene into the tissue (TI) were both shown to display Michaelis-Menten kinetics (Km Ox = 0.9 × 10–6 M liquid phase, Vmax Ox = 2.4 × 10–10 moles g– dry mass h–1 Km TI = 1.6 × 10–6 M liquid phase, Vmax TI = 4.5 × 10–10 moles g–1 dry mass h–1). Propylene competitively inhibited both Ox (Ki = 7.0 × 10–6 M) and TI (Ki = 3.7 × 10–7 M). A system comparable to Ox was absent from imbibed cotyledons of Vicia faba L. cv. Aquadulce even at saturating concentrations of ethylene similar to those used in kinetic analysis on Pisum. Silver ions were shown to inhibit TI but promoted Ox, while carbon dioxide inhibited Ox but promoted TI. Kinetic data on both these effects are presented. Data on the effect of a range of concentrations of CO2 on TI and Ox are also presented
EQUIP : Ensuring the Quality of Urinary Iodine Procedures
In 2001, the Centers for Disease Control and Prevention (CDC) established the EQUIP program to help laboratories worldwide assess the accuracy of their urinary iodine analysis and to provide them with technical support.CS120995Publication date from document properties.EQUIP_Brochure.pd