Insights into role of synergistic interplay among collagen type I, collagen type II, and water on the structure and nanomechanics of collagen fibrils in annulus fibrosus: a molecular dynamics study

Annulus Fibrosus’s (AF) multi-directional load-bearing ability manifests from Nature’s design wherein type I collagen (COL-I) dominates outer AF and type II collagen (COL-II) dominates inner AF with increase in proteoglycan and water concentration. This indicates a synergistic chemo-mechanical interplay among constituents, contributing towards AF’s load-bearing nature. Present work investigates the interplay among COL-I, COL-II and water, and their role in AF collagen fibril nanomechanics using molecular dynamics simulations. Consequently, atomistic models of collagen microfibrils are constructed for four lamellar regions from outer to inner AF, by increasing COL-II and water concentration from 0% to 75%, and 65% to 75%. Results show an increase in local hydration around COL-II component and increase in intermolecular separation (21 Å to 23 Å), with increase in COL-II and water concentration towards inner AF. A combined increase in local hydration and intermolecular separation enhances intermolecular sliding – contributing to a reduction in tensile modulus from 2.1 to 1.6 GPa. Reduction in microfibril tensile modulus towards inner AF contributes to reduction in tensile modulus of AF lamellae towards inner AF, as reported in literature. Furthermore, increase in COL-II and water concentration shifts compressive behaviour from buckling to non-buckling dominant – enhancing collagen fibrils’ mechanical stability towards inner AF.</p

A rapid qNMR protocol for the analysis of triclofos sodium in solution state pharmaceutical dosage formulations

95-101A quaitative 31P{1H} nuclear magnetic resonance (NMR) spectroscopy has been used for quantification of triclofos sodium (TCFS) in syrup formulations. Its hydrolysis product 2,2,2-trichloroethanol (TCE) has been quantified by 1H NMR spectroscopy. Standard addition to syrup formulations is used for the quantification of these components. Dimethylsulfone (DMS) and hexamethyl benzene-1,3,5-triyltris(methylene)triphosphonate (HMBTP) have been used as internal standards for quantitative 1H NMR and 31P{1H} NMR respectively. All NMR experiments are performed on 400 MHz NMR spectrometer equipped with a room temperature broadband observe probe. The method is simple, rapid, and easy to implement. It also shows excellent accuracy (recoveries for TCFS 98.9-101.5% and TCE 98.6 to 99.9%), linearity (r2>0.99), range, precision, accuracy and robustness. Four commercially available formulations have been subjected to the developed method. The average concentration for TCFS is found to be 93±4 mg/mL in the commercially available drug samples. </span

Comparative evaluation of atenolol and clonidine premedication on cardiovascular response to nasal speculum insertion during trans-sphenoid surgery for resection of pituitary adenoma: A prospective, randomised, double-blind, controlled study

Severe cardiovascular responses in the form of tachycardia and hypertension following nasal speculum insertion occur during sublabial rhinoseptal trans-sphenoid approach for resection of small pituitary tumours. We compare the effects of preoperative administration of clonidine (α-2 agonist) and atenolol (α-blocker) over haemodynamic response, caused by speculum insertion during trans-sphenoid pituitary resection. We enrolled 66 patients in age range 18-65 years, of ASA I–II, and of either sex undergoing elective sublabial rhinoseptal trans-sphenoidal hypophysectomy. Group I (control) received placebo, group II (clonidine) received tablet clonidine 5 µg/kg, and group III (atenolol) received tablet atenolol 0.5 mg/kg. The heart rate increased on speculum insertion and 5 and 10 minutes following speculum insertion as compared to the pre-speculum values in the control group, while no change in the heart rate was observed in other groups (P<0.05). There was a rise in the mean arterial pressure during and 5, 10, and 15 minutes after nasal speculum insertion in the control group, whereas it was not seen in other groups (P<0.05). We therefore suggest that oral clonidine and oral atenolol (given 2 hours prior to surgery) is an equally effective and safe method of attenuating haemodynamic response caused by nasal speculum insertion during trans-sphenoid pituitary resection

Book Tile: Nanomaterials in Plants, Algae, and Microorganisms Concepts and Controversies

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Plant growth and development vs. high and low levels of plant-beneficial heavy metal ions

Heavy metals (HMs) exists in the environment in both forms as essential and non-essential. These HM ions enter in soil biota from various sources like natural and anthropogenic. Essential HMs such as cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), and zinc (Zn) plays a beneficial role in plant growth and development. At optimum level these beneficial elements improves the plant’s nutritional level and also several mechanisms essential for the normal growth and better yield of plants. The range of their optimality for land plants is varied. Plant uptake heavy metals as a soluble component or solubilized them by root exudates. While their presence in excess become toxic for plants that switches the plant’s ability to uptake and accumulate other nonessential elements. The increased amount of HMs within the plant tissue displays direct and indirect toxic impacts. Such direct effects are the generation of oxidative stress which further aggravates inhibition of cytoplasmic enzymes and damage to cell structures. Although, indirect possession is the substitution of essential nutrients at plant’s cation exchange sites. These ions readily influence role of various enzymes and proteins, arrest metabolism, and reveal phytotoxicity. On account of recent advancements on beneficial HMs ions Co, Cu, Fe, Mn, Mo, Ni, and Zn in soil-plant system, the present paper: overview the sources of HMs in soils and their uptake and transportation mechanism, here we have discussed the role of metal transporters in transporting the essential metal ions from soil to plants. The role played by Co, Cu, Fe, Mn, Mo, Ni, and Zn at both low and high level on the plant growth and development and the mechanism to alleviate metal toxicity at high level have been also discussed. At the end, on concluding the article we have also discussed the future perspective in respect to beneficial HM ions interaction with plant at both levels

Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

Iron (Fe) is a micronutrient that plays an important role in agriculture worldwide because plants require a small amount of iron for its growth and development. All major functions in a plant's life from chlorophyll biosynthesis to energy transfer are performed by Fe (Brumbarova et al., 2008; Gill and Tuteja, 2011). Iron also acts as a major constituent of many plant proteins and enzymes. The acquisition of Fe in plants occurs through two strategies, i.e., strategy I and strategy II (Marschner and Römheld, 1994). Under various stress conditions, Nramp and the YSL gene families help in translocation of Fe, which further acts as a mineral regulatory element and defends plants against stresses. Iron plays an irreplaceable role in alleviating stress imposed by salinity, drought, and heavy metal stress. This is because it activates plant enzymatic antioxidants like catalase (CAT), peroxidase, and an isoform of superoxide dismutase (SOD) that act as a scavenger of reactive oxygen species (ROS) (Hellin et al., 1995). In addition to this, their deficiency as well as their excess amount can disturb the homeostasis of a plant's cell and result in declining of photosynthetic rate, respiration, and increased accumulation of Na+ and Ca− ions which culminate in an excessive formation of ROS. The short-range order hydrated Fe oxides and organic functional groups show affinities for metal ions. Iron plaque biofilm matrices could sequester a large amount of metals at the soil–root interface. Hence, it has attracted the attention of plant physiologists and agricultural scientists who are discovering more exciting and hidden applications of Fe and its potential in the development of bio-factories. This review looks into the recent progress made in putting forward the role of Fe in plant growth, development, and acclimation under major abiotic stresses, i.e., salinity, drought, and heavy metals