Phenomena In Biophysics Research Articles

A phenomena in bio physics: The Grand Lemurrian Sun Salutation

The sun salutation is not mentioned in Hatha yoga tall. This was added to Hatha yoga practices in later years by somebody. We do not know the formulator/ designer. But one thingis certain that this packageis very applicable and useful. But this practicehas several seriousside effects also. The classicalSurya Namaskar involvestwelve postures namely,Hasta Uttanasana, Hastapadasana, Ashwa Sanchalanasana, Dandasana, Ashtanga Namaskara, Bhujangasana, Adho Mukha Svanasana, Ashwa Sanchalanasana, Hastapadasana, and Tadasana It should be performedalong with mantra recitation and breathing techniques, otherwise it will not be fruitful.

Headgroup-Ordered Monolayers of Uncharged Glycolipids Exhibit Selective Interactions with Ions.

Selective interactions of ions with charge-neutral saccharides can have far-reaching consequences in biological and wet-technological contexts but have so far been observed only indirectly. Here, we directly quantify by total-reflection X-ray fluorescence the preferential accumulation of ions near uncharged saccharide surfaces in the form of glycolipid Langmuir monolayers at air/water interfaces exhibiting different levels of structural ordering. Selective interactions with ions from the aqueous subphase are observed for monolayers featuring crystalline ordering of the saccharide headgroups, as determined by grazing-incidence X-ray diffraction. The attracted ion species depend on the structural motifs displayed by the ordered saccharide layer. Our results may constitute a basis to understand the salt-specific swelling of wood materials and various phenomena in membrane biophysics.

Fabrication and characterization of a microfluidic flow cytometer for the advanced undergraduate laboratory

Microfluidic devices can be used to explore a vast range of phenomena in biophysics and soft-matter physics. While the popularity of these devices is in part driven by the ease of soft-lithography, most research labs still depend upon expensive, clean-room fabrication of photoresist molds, which can make this technique inaccessible to the undergraduate laboratory. However, there are much simpler, if coarser, approaches to designing molds that are capable of producing surprisingly complicated devices. Here, we detail the fabrication and characterization of a microfluidic device for flow cytometry or particle sorting on a chip. Our device is a layered polydimethylsiloxane chip that uses a series of Quake valves to sort. The molds were fabricated on equipment accessible to most undergraduate labs. The techniques and physics we discuss in this manuscript can be employed to create an almost endless variety of devices for learning about complex fluid mechanics, mesoscopic, soft-matter, and biological physics.

Cellular response to high pulse repetition rate nanosecond pulses varies with fluorescent marker identity

Nanosecond electric pulses (nsEP's) are a well-studied phenomena in biophysics that cause substantial alterations to cellular membrane dynamics, internal biochemistry, and cytoskeletal structure, and induce apoptotic and necrotic cell death. While several studies have attempted to measure the effects of multiple nanosecond pulses, the effect of pulse repetition rate (PRR) has received little attention, especially at frequencies greater than 100 Hz. In this study, uptake of Propidium Iodide, FM 1–43, and YO-PRO-1 fluorescent dyes in CHO-K1 cells was monitored across a wide range of PRRs (5 Hz–500 KHz) using a laser-scanning confocal microscope in order to better understand how high frequency repetition rates impact induced biophysical changes. We show that frequency trends depend on the identity of the dye under study, which could implicate transmembrane protein channels in the uptake response due to their chemical selectivity. Finally, YO-PRO-1 fluorescence was monitored in the presence of Gadolinium (Gd3+), Ruthenium Red, and in calcium-free solution to elucidate a mechanism for its unique frequency trend.

An Intracellular Calcium Oscillation Model and its Property

Intracellular Ca2+ concentration oscillation is one of thetypical nonlinear dynamical phenomena in biophysics. According to theexperimental facts that when stimulated by different agonists, thecytosolic Ca2+ oscillations of hepatocytes show nearly constantamplitude for two different oscillation-form, simple spikes and complexbursts, we build a new 4-variables model based on the two modelsproposed by Hoefer [Biophys J. 77 (1999) 1244] and Kummeret al. [Biophys. J. 79 (2000) 1188] Our model cansimulate both simple-spike and multi-spike-burst oscillations withamplitude of 0.5-0.7 µmol/L in a rather wide range of parameters.

Modeling the hyperelasticity of magnetic field sensitive gels

The continuum theory, previously developed to quantitatively account for the large deformations observed in gels endowed with electric properties, is extended to magnetic field sensitive gels (ferromagnetic or diamagnetic in origin). The derived analytical formula for the dependence of the gel displacement on the magnetic field can be applied either to control recently developed biomimetic valves and possible artificial muscles constructions or to interpret similar phenomena in biophysics.

A Simple Method for Evaluating Partition Functions of Linear Polymers

A simple method for evaluating partition functions of linear systems is presented. The method produces the generating function of the partition functions of systems of all sizes. The method keeps the simplicity of Lifson's sequence-generating function method. Unlike the sequence-generating function method, which only applies to infinite systems, the method presented here applies to both finite and infinite systems. Explicit expression of the partition functions can be readily derived directly from the generating function. The method provides a simple protocol to handle a large range of models that come out in studying cooperative phenomena in physical chemistry and biophysics.

Twirling and whirling: viscous dynamics of rotating elastic filaments.

Motivated by diverse phenomena in cellular biophysics, including bacterial flagellar motion and DNA transcription and replication, we study the overdamped nonlinear dynamics of a rotationally forced filament with twist and bend elasticity. Competition between twist injection, twist diffusion, and writhing instabilities is described by coupled PDEs for twist and bend evolution. Analytical and numerical methods elucidate the twist/bend coupling and reveal two regimes separated by a Hopf bifurcation: (i) diffusion-dominated axial rotation, or twirling, and (ii) steady-state crankshafting motion, or whirling. The consequences of these phenomena for self-propulsion are investigated, and experimental tests proposed.