Surface plasmon resonance-based immunoassay for procalcitonin

A surface plasmon resonance (SPR) biosensor has been developed for rapid immunoassay of procalcitonin (PCT) with high detection sensitivity and reproducibility. The 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC)-activated protein A (PrA), diluted in 1% (v/v) 3-aminopropyltriethoxysilane (APTES) was dispensed on a KOH-treated Au-coated SPR chip, resulting in the covalent binding of PrA in 30 min. This “single-step” PrA immobilization strategy led to the oriented binding of the anti-PCT antibody (Ab) on a PrA-functionalized gold (Au) chip. The leach-proof immobilization procedure is five-fold faster than conventional counterparts, enabling high detection specificity and reproducibility. The IA detects 4–324 ng mL⁻¹ of PCT with a limit of detection (LOD) and a limit of quantification (LOQ) of 4.2 ng mL⁻¹ and 9.2 ng mL⁻¹, respectively. It was capable of detecting PCT in real sample matrices and patient samples with high precision. The Ab-bound SPR chips were stable for more than five weeks.     

Working group report: Heavy-ion physics and quark-gluon plasma

This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of quark-gluon plasma believed to have created in heavy-ion collisions and in early Universe are reported.     

Shortest Path Problem on a Network with Imprecise Edge Weight

A network with its arc lengths as imprecise number, instead of a real number, namely, interval number and triangular fuzzy number is considered here. Existing ideas on addition and comparison between two imprecise numbers of same type are introduced. To obtain a fuzzy shortest path from a source vertex to all other vertices, a common algorithm is developed which works well on both types of imprecise numbers under consideration. In the proposed algorithm, a decision-maker is to negotiate with the obtained fuzzy shortest paths according to his/her view only when the means are same but the widths are different of the obtained paths. Otherwise, a fuzzy optimal path is obtained to which the decision-maker always satisfies with different grades of satisfaction. All pairs fuzzy shortest paths can be found by repeated use of the proposed algorithm.     

Cellphone-based devices for bioanalytical sciences

During the last decade, there has been a rapidly growing trend toward the use of cellphone-based devices (CBDs) in bioanalytical sciences. For example, they have been used for digital microscopy, cytometry, read-out of immunoassays and lateral flow tests, electrochemical and surface plasmon resonance based bio-sensing, colorimetric detection and healthcare monitoring, among others. Cellphone can be considered as one of the most prospective devices for the development of next-generation point-of-care (POC) diagnostics platforms, enabling mobile healthcare delivery and personalized medicine. With more than 6.5 billion cellphone subscribers worldwide and approximately 1.6 billion new devices being sold each year, cellphone technology is also creating new business and research opportunities. Many cellphone-based devices, such as those targeted for diabetic management, weight management, monitoring of blood pressure and pulse rate, have already become commercially-available in recent years. In addition to such monitoring platforms, several other CBDs are also being introduced, targeting e.g., microscopic imaging and sensing applications for medical diagnostics using novel computational algorithms and components already embedded on cellphones. This report aims to review these recent developments in CBDs for bioanalytical sciences along with some of the challenges involved and the future opportunities.

Role of silica coated magnetic nanoparticle on cell flocculation,lipid extraction and linoleic acid production from Chlorella pyrenoidosa

Abstract

In the present work, it has been observed that magnetic (Fe₃O₄) – silica core- shell nanoparticles helps in flocculation of Chlorella pyrenoidosa cells with simultaneous production of linoleic acid. The mean particle size in Dynamic light scattering (DLS) of the silica coated magnetic nanoparticle was estimated 444.7?nm. The characterization of nanoparticles was also performed by X-ray diffraction technique (XRD). Apart from flocculation, it has been observed that in presence of magnetic silica core- shell nanoparticles the amount of lipid obtained was four times than that of control. On the contrary, in presence of these nanoparticles, linoleic acid (18:2) has been produced in Chlorella pyrenoidosa cells almost by 80% whereas, it has been noticed only 8.73% in control. This is the first report where the linoleic acid has been obtained as major component of microalgal fatty acid methyl esters (FAME) having important application in nutraceuticals and pharmaceutical sectors.     

Analysis of the nonlinear vibration of a two-mass–spring system with linear and nonlinear stiffness

An analytical approach is developed for areas of nonlinear science such as the nonlinear free vibration of a conservative, two-degree-of-freedom mass–spring system having linear and nonlinear stiffnesses. The main contribution of this research is twofold. First, it introduces the transformation of two nonlinear differential equations for a two-mass system using suitable intermediate variables into a single nonlinear differential equation and, more significantly, the treatment of a nonlinear differential system by linearization coupled with Newton’s method. Secondly, the major section is the solving of the governing nonlinear differential equation where the displacement of the two-mass system can be obtained directly from the linear second-order differential equation using a first-order variational approach. The aforementioned approach proposed by J.H. He, who actually developed the method, is exactly He’s variational method. This approach is an explicit method with high validity for resolving strong nonlinear oscillation system problems. Two examples of nonlinear two-degree-of-freedom mass–spring systems are analyzed, and verified with published results and exact solutions. The method can be easily extended to other nonlinear oscillations and so could be widely applicable in engineering and science.     

Efficient Transformation of Furfuryl Alcohol Into Ethyl Levulinates via Alcoholysis Reaction Catalyzed by SnO2/H-Mordenite Catalyst

Catalysis Surveys from Asia - Catalytic production of ethyl levulinate by alcoholysis of furfuryl alcohol with ethanol was investigated over H-mordenite supported Sn catalyst under atmospheric N2...     

Perspectives on electrochemical biosensing of COVID-19

Rapid detection of human coronavirus disease 2019, termed as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or COVID-19 infection, is urgently needed for containment strategy owing to its unprecedented spreading. Novel biosensors can be deployed in remote clinical settings without central facilities for infection screening. Electrochemical biosensors serve as analytical tools for rapid detection of viral structure proteins, mainly spike (S) and nucleocapsid (N) proteins, human immune responses, reactive oxygen species, viral ribonucleic acid, polymerase chain reaction by-products, and other potential biomarkers. The development of point-of-care testing devices is challenging due to the requirement of extensive validation, a time-consuming and expensive step. Together with specific biorecognition molecules, nanomaterial-based biosensors have emerged for the fast detection of early viral infections.