Real time imaging of single extracellular vesicle pH regulation in a microfluidic cross-flow filtration platform

Extracellular vesicles (EVs) are cell-derived membranous structures carrying transmembrane proteins and luminal cargo. Their complex cargo requires pH stability in EVs while traversing diverse body fluids. We used a filtration-based platform to capture and stabilize EVs based on their size and studied their pH regulation at the single EV level. Dead-end filtration facilitated EV capture in the pores of an ultrathin (100 nm thick) and nanoporous silicon nitride (NPN) membrane within a custom microfluidic device. Immobilized EVs were rapidly exposed to test solution changes driven across the backside of the membrane using tangential flow without exposing the EVs to fluid shear forces. The epithelial sodium-hydrogen exchanger, NHE1, is a ubiquitous plasma membrane protein tasked with the maintenance of cytoplasmic pH at neutrality. We show that NHE1 identified on the membrane of EVs is functional in the maintenance of pH neutrality within single vesicles. This is the first mechanistic description of EV function on the single vesicle level.

Pengukuran Indeks Bias Larutan untuk Mengetahui Kadar Gula dalam Tebu dengan Menggunakan Metode Difraksi Fraunhofer Celah Tunggal

Refractive index measurements of sugar solutions have been carried out in several concentrations. The method used is fraunhofer diffraction. The equation of relationship between the concentration of the sugar solution and the refractive index based on the results of the linear fitting can be written as, Where n is the refractive index of the sugar solution and x is the solution concentration. From this equation, a fairly small gradient value of 1.59145 is obtained. This shows that a 1% increase in the concentration of the sugar solution will cause the refractive index to decrease by 1.59145. The refractive index of the solution changes when the concentration changes. The refractive index of the solution increases with increasing concentration of the solution. This is because along with the increase in concentration, more glucose is found in the sugar solution. As a result, the solution will be more concentrated because the glucose molecules that are arranged are getting denser. The above equation is used to calculate the concentration of sugar in sugar cane. It was found that brown sugar cane had a concentration of 33.38% compared to 26.34% in yellow sugarcane. While the measurement of the concentration of sugar cane in different planting areas shows almost the same results, this is because the level of accuracy of the tool is still large when compared to the difference in the concentration of the sugar solution.

Band Gap Narrowing and Electrical Properties of (1-x)BaTiO3-xSrFe0.5Nb0.5O3 Lead-Free Ceramics

The composite materials in the form of (1-x)BaTiO3-xSrFe0.5Nb0.5O3((1-x)BT-xSFN) are synthesized via the solid-state reaction route. Structure, optical behaviors and electrical properties of (1-x)BT-xSFN are studied. It can be noted that the structure of the synthesized solid solution changes from the tetragonal phase to the cubic phase with increase of x-value. Due to the increase in content of double perovskite SFN, the optical band gaps of doped BT decrease to a minimum of 2.66 eV, which is smaller than that of pure BT (3.21 eV). However, the ferroelectric property deteriorates with the addition of dopants, which result from the lattice distortion caused by the substitution of Sr2+ and Fe3+/Nb5+ for Ba2+ and Ti4+, respectively. These results provide new insights into the control of the structure, optical behaviors and ferroelectric properties in BT-based oxides.

Sarcoplasmic reticular Ca2+-ATPase inhibition paradoxically upregulates murine skeletal muscle Nav1.4 function

Skeletal muscle Na+ channels possess Ca2+- and calmodulin-binding sites implicated in Nav1.4 current (INa) downregulation following ryanodine receptor (RyR1) activation produced by exchange protein directly activated by cyclic AMP or caffeine challenge, effects abrogated by the RyR1-antagonist dantrolene which itself increased INa. These findings were attributed to actions of consequently altered cytosolic Ca2+, [Ca2+]i, on Nav1.4. We extend the latter hypothesis employing cyclopiazonic acid (CPA) challenge, which similarly increases [Ca2+]i, but through contrastingly inhibiting sarcoplasmic reticular (SR) Ca2+-ATPase. Loose patch clamping determined Na+ current (INa) families in intact native murine gastrocnemius skeletal myocytes, minimising artefactual [Ca2+]i perturbations. A bespoke flow system permitted continuous INa comparisons through graded depolarizing steps in identical stable membrane patches before and following solution change. In contrast to the previous studies modifying RyR1 activity, and imposing control solution changes, CPA (0.1 and 1 µM) produced persistent increases in INa within 1–4 min of introduction. CPA pre-treatment additionally abrogated previously reported reductions in INa produced by 0.5 mM caffeine. Plots of peak current against voltage excursion demonstrated that 1 µM CPA increased maximum INa by ~ 30%. It only slightly decreased half-maximal activating voltages (V0.5) and steepness factors (k), by 2 mV and 0.7, in contrast to the V0.5 and k shifts reported with direct RyR1 modification. These paradoxical findings complement previously reported downregulatory effects on Nav1.4 of RyR1-agonist mediated increases in bulk cytosolic [Ca2+]. They implicate possible local tubule-sarcoplasmic triadic domains containing reduced [Ca2+]TSR in the observed upregulation of Nav1.4 function following CPA-induced SR Ca2+ depletion.

Mathematical models of rock mass affected by high pressure gradients

The authors propose to solve the problems connected with high pressure gradients using a model of a linearly elastic body with a structural parameter. The closed finite difference system of equations is formulated for plain strain deformation conditions. The problem on deformation of rock mass in the vicinity of an underground opening affected by mixed-type gravity-and-tectonic stress field is solved. It is demonstrated that addition of the structure in the solution changes the value of the stress concentration coefficient.

A polynomial time test to detect numbers with many exceptional points

For each algebraic number [Formula: see text] and each positive real number [Formula: see text], the [Formula: see text]-metric Mahler measure [Formula: see text] creates an extremal problem whose solution varies depending on the value of [Formula: see text]. The second author studied the points [Formula: see text] at which the solution changes, called exceptional points for[Formula: see text] . Although each algebraic number has only finitely many exceptional points, it is conjectured that, for every [Formula: see text], there exists a number having at least [Formula: see text] exceptional points. In this paper, we describe a polynomial time algorithm for establishing the existence of numbers with at least [Formula: see text] exceptional points. Our work constitutes an improvement over the best known existing algorithm which requires exponential time. We apply our main result to show that there exist numbers with at least [Formula: see text] exceptional points, another improvement over previous work which was only able to reach [Formula: see text] exceptional points.

Efficient Removal of Methyl Orange and Rhodamine-B Dyes with Low Cost Banana Peel Activated Carbon

Acid activated carbon obtained from cheap, non-toxic and locally available banana peel was used as a low cost and efficient adsorbent for the removal of dyes methyl orange and rhodamine-B from the aqueous solution. Changes in the resulting material before and after activation and after treatment were studied by different techniques, such as SEM-EDX, XRD, FTIR measurements. Effects of duration of treatment, amount of banana peel activated carbon, pH, and initial methyl orange and rhodamine-B concentration, on the removal of dye were studied to get optimum conditions for maximum dye removal. Removal efficiency of the activated ash remains almost constant in a wide range of pH from 2.5 to 5.6. In 75 min at room temperature removal of 98.5 % methyl orange (anionic) and 99.0 % rhodamine-B (cationic) dyes with 0.1 g and 0.125 g, respectively was obtained from the contaminated water having 10 ppm dye concentration.

Peritoneal Dialysis

SUMMARY Peritoneal dialysis (PD) is a renal replacement therapy based on infusing a sterile solution into the peritoneal cavity through a catheter and provides for the removal of solutes and water using the peritoneal membrane as the exchange surface. This solution, which is in close contact with the capillaries in the peritoneum, allows diffusion solute transport and osmotic ultrafiltration water loss since it is hyperosmolar to plasma due to the addition of osmotic agents (most commonly glucose). Infusion and drainage of the solution into the peritoneal cavity can be performed in two ways: manually (continuous ambulatory PD), in which the patient usually goes through four solution changes throughout the day, or machine-assisted PD (automated PD), in which dialysis is performed with the aid of a cycling machine that allows changes to be made overnight while the patient is sleeping. Prescription and follow-up of PD involve characterizing the type of peritoneal transport and assessing the offered dialysis dose (solute clearance) as well as diagnosing and treating possible method-related complications (infectious and non-infectious).

Synthesis of 1,1′-Bis(1-Methyl/Chloro-2,3,4,5-Tetraphenyl-1-Silacyclopentadienyl) [Ph4C4Si(Me/Cl)-(Me/Cl)SiC4Ph4] from Silole Anion [MeSiC4Ph4]−•[Li+ or Na+] and Silole Dianion [SiC4Ph4]2−•2[Li+]; Oxidative Coupling of Silole Anion [MeSiC4Ph4]−•[Li+ or Na+] by Ferrous Chloride (FeCl2) and Oxidative Coupling and Chlorination of Silole Dianion [SiC4Ph4]2−•2[Li+] by Cupric Chloride (CuCl2)

A reaction of silole anion {[MeSiC4Ph4]−•[Li+ or Na+] (1) with anhydrous ferrous chloride (FeCl2) in THF (tetrahydrofuran) gives 1,1′-bis(1-methyl-2,3,4,5-tetraphenyl-1-silacyclopentadienyl) [Ph4C4Si(Me)-(Me)SiC4Ph4] (2) with precipitation of iron metal in high yield. Silole dianion {[SiC4Ph4]2−•2[Li+] (3) is added to anhydrous cupric chloride (CuCl2) in THF at −78 °C, then the dark red solution changes into a greenish solution. From the solution, a green solid is isolated, and stirring it in toluene at room temperature provides quantitatively 1,1′-bis(1-chloro-2,3,4,5-tetraphenyl-1-silacyclopentadienyl) [Ph4C4Si(Cl)-(Cl)SiC4Ph4] (4) with precipitation of copper metal in toluene. The green solid is suggested to be 1,1′-bissilolyl bisradical [Ph4C4Si-SiC4Ph4]2• (8), and lithium cuprous chloride salts {[Li2CuICl2]+•[CuICl2]−}. Both reactions are initiated by single-electron transfer (SET) from the electron-rich anionic silole substrates (1 and 3) to iron(II) and copper(II).