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  • The lanthanide series of chemical elements


    The lanthanide series of chemical elements comprises the fifteen metallic chemical elements with atomic numbers 57 through 71, from lanthanum to lutetium. Though originally described as ‘‘rare earths’’ because of their natural occurrence as metal oxides, they are not particularly rare. The lanthanide series is the group of elements in which the 4f sublevel is being filled. Some lanthanides are highly reactive with oxygen, which can directly affect this silver color. Lanthanides are known to adopt the oxidation state of +3. They tend to be most stable at this state. Oxidation state is a calculated value used to show the number of electrons lost or gained.43, 44, 45, 46, 47, 48 Dysprosium is a heavy rare earth element.49, 50 In the course of the developments lanthanum tungstate have been made as nanoparticles and electrochemically characterized by several researchers. Owing to the large surface area, good conductivity and outstanding catalytic activity, lanthanum tungstate nanoparticles have been widely used for the development of electrochemical sensors and biosensors applications. Among the different lanthanide tungstates, Dy2(WO4)3 has been applied in catalysis,51, 52, 53 and offers interesting optical properties. In the light of the above information, this work aims at developing a modified electrode for the sensitive determination of epinephrine and acetylcholine, using Dy2(WO4)3 nanoparticles to enhance the properties of screen printed electrodes. The resulting electrode is successfully applied for the determination of epinephrine and LB Broth, Miller in the real samples.
    Results and discussion
    Conclusions SPEs modified with Dy(WO4)3 nanoparticles were developed and used as a novel sensor for the sensitive and selective determination of epinephrine and acetylcholine in their mixtures. The resulting device is found to act as a portable, inexpensive, and disposable tool for the determination of the analytes. The unique properties of Dy2(WO4)3 nanoparticles, are found to present the sensor with considerable electrocatalytic activity in oxidizing the analytes, and also resolving their overlapping anodic peaks into two distinct peaks. The detection limits of the electrode for epinephrine and acetylcholine are determined to be 0.5 and 0.7 μmol/L respectively, and overall the electrode is considered as an excellent tool for clinical analyses where the determination of trace levels of epinephrine and acetylcholine is required.
    Introduction Inhaled bronchodilator treatment with a long acting muscarinic antagonist (LAMA) has been demonstrated to reduce symptoms and the risk of exacerbations as well as improve the health status and exercise tolerance in COPD. Recently, LAMA has been also shown to reduce symptoms and decrease the risk of exacerbations in asthma. These effects are thought to be mainly mediated by a bronchodilatory effect and inhibitory effect on mucus secretion by the drug. However, increasing evidence from cell culture and animal studies suggests that anti-muscarinic drugs could possess anti-inflammatory effects. Recent studies have revealed that acetylcholine (ACh) can be synthesized and released from both neuronal and non-neuronal cells, and the released ACh could potentiate airway inflammation and remodeling in airway diseases. This review will focus on recent findings about the possible involvement of ACh in airway inflammation and remodeling via muscarinic receptors, and the anti-inflammatory effect of anti-muscarinic drugs in airway diseases.
    Cholinergic regulation in airways ACh is recognized as a neurotransmitter in the nervous system that regulates various activities including neural transmission, smooth muscle contraction and mucus secretion. In airways, cholinergic innervation is the predominant neural bronchoconstrictor pathway. Chronic irritants such as cigarette smoke and air pollution, or mediators released from inflammatory cells stimulate airway sensory nerve C-fibers, which release ACh from efferent nerve endings via the vagal reflex pathway (Fig. 1). Recently, the cholinergic regulation of airways has actually been demonstrated in COPD patients by bronchoscopic ablation of parasympathetic pulmonary nerves surrounding the main bronchi.