Effect of Cytochrome C on the Conductance of Asolectin Membranes and the Occurrence of Through Pores at Different pHs.

The study of the electrical parameters of asolectin bilayer lipid membranes in the presence of cytochrome c (cyt c) at various concentrations showed that an increase in the concentration of cyt c leads to an increase in the membrane conductance and the appearance of through pores. The studied membranes did not contain cardiolipin, which is commonly used in studying the effect of cyt c on membrane permeability. In the presence of cyt c, discrete current fluctuations were recorded.

Different effects of two Poloxamers (L61 and F68) on the conductance of bilayer lipid membranes.

The integral conductance of planar lipid bilayer membranes in the presence of two Poloxamers (Pluronics) L61 and F68 with the same lengths of hydrophobic poly(propylene oxide) blocks and the different lengths of hydrophilic poly(ethylene oxide) blocks increases with an increase in the concentration of both Pluronics; however, the shape of the conductance-concentration curves is super linear for L61 and sublinear for F68. In the presence of both Pluronics, rare discrete current jumps are observed against the background of continuous current. At high concentrations, the I-V curves of membranes with both L61 and F68 became nonlinear at sufficiently low voltages but differed significantly.

Bilayer Lipid Membrane as Memcapacitance: Capacitance-Voltage Pinched Hysteresis and Negative Insertion Conductance.

Inelastic (dissipative) effects of different natures in lipid bilayer membranes can lead to hysteresis phenomena. Early, it was shown that lipid bilayer membranes, under the action of a periodic sinusoidal voltage, demonstrate pinched-hysteresis loops in the experimental capacitance-voltage dependences and are almost the only example of the physical implementation of memcapacitance. Here, we propose an equivalent circuit and mathematical framework for analyzing the dynamic nonlinear current response of a lipid bilayer membrane as an externally controlled memcapacitance.

Surface and Structure of Phosphatidylcholine Membranes Reconstructed with CoFeO Nanoparticles.

Structural changes in phosphatidylcholine lipid membranes caused by the introduction of insoluble CoFeO nanoparticles (NPs) are analyzed. Changes in nuclear magnetic resonance spectrum, infrared spectrum, and ionic conductivity of membranes are observed with the addition of NPs. The presence of NPs in membranes is proved by atomic force and magnetic force microscopy.

Systematic review of artificial intelligence tack in preventive orthopaedics: is the land coming soon?

Purpose: This study aims to describe and assess the current stage of the artificial intelligence (AI) technology integration in preventive orthopaedics of the knee and hip joints.

Materials And Methods: The study was conducted in strict compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. Literature databases were searched for articles describing the development and validation of AI models aimed at diagnosing knee or hip joint pathologies or predicting their development or course in patients.

Effect of Cobalt Ferrite Nanoparticles in a Hydrophilic Shell on the Conductance of Bilayer Lipid Membrane.

We measured the conductance of bilayer lipid membranes of diphytanoylphosphatidylcholine induced by interaction with cubic magnetic nanoparticles (MNPs) of cobalt ferrite 12 and 27 nm in size and coated with a hydrophilic shell. The MNP coating is human serum albumin (HSA) or polyethylene glycol (PEG). The interaction of nanoparticles added to the bulk solution with the lipid bilayer causes the formation of metastable conductive pores, which, in turn, increases the integral conductance of the membranes.

Passive Acoustic Thermometry of the Chest of a Person with COVID-19.

Passive acoustic thermometry (PAT) was used to study the dynamics of changes in the chest temperature of a person with COVID-19 over the course of about two and a half weeks after quarantine. PAT, which can measure deep body temperature, showed that the integral temperature of tissues surrounding the lungs increased from 32.2 ± 0.

Estimation of the parameters of the Smoluchowski equation describing the occurrence of pores in a bilayer lipid membrane under soft poration.

The conductive lipid pores occurring in planar bilayer membranes are known to manifest themselves experimentally as current fluctuations. Reliable recording of such fluctuations during phase transitions, as well as in membranes with various additives (for example, SDS), allows one to determine the characteristics of hypothetical hydrophilic pores, namely, their number, sizes, lifetimes, and duration of time intervals between pores. Because, in contrast with electroporation, the emergence of pores in a membrane does not require high voltages, this process is called soft poration.

Lipoic acid nanoforms based on phosphatidylcholine: production and characteristics.

We describe the dynamics of lipoic acid (LA) alone, incorporated in liposomes and as a part of nanoemulsions. Mass spectrometry shows that LA in water forms aggregates of two or three molecules in the form of a negatively charged ion and a neutral molecule. Phosphatidylcholine (PC)-based nanoforms of LA as liposomes and nanoemulsions with a particle size equal to 145 nm are characterized by a high degree of incorporation of LA into the nanoparticles and long-term stability during storage at room temperature.

Increase in the current variance in bilayer lipid membranes near phase transition as a result of the occurrence of hydrophobic defects.

Most researchers associate the increase in the permeability of lipid bilayers of artificial and biological membranes observed in various experiments with the formation of hypothetical hydrophobic and hydrophilic pores. Although the existence of hydrophobic defects, as the first stage of the formation of a hydrophilic pore, was hypothesized decades ago from electroporation experiments, the difficulty of describing this stage is determined by the lack of experimental data confirming the existence or at least associated with hydrophobic pores. We explored the increase in the current variance through the lipid membrane, observed when approaching the phase transition from the side of high temperatures, and have associated it with capacitive currents arising in response to the formation of hydrophobic pores.

The effects of SDS at subsolubilizing concentrations on the planar lipid bilayer permeability: Two kinds of current fluctuations.

Detergent effects on lipid bilayers of artificial and biological membranes at subsolubilizing concentrations are known to include the membrane permeabilization which manifests itself through both a flip-flop of detergent molecules from the outer monolayer to the inner monolayer and the membrane leakage of entrapped solutes. We have explored the current fluctuations occurring in planar BLM of asolectin in the presence of ionic detergent SDS at subsolubilizing concentration. Two groups of current fluctuations which the average duration differs by two orders of magnitude can be distinguished.

Erlang flow of hydrophilic pore formation and closure events in a lipid bilayer during phase transition resulting from diffusion in the radius space.

The Smoluchowski equation with an energy profile of a special type and an assumed hydrophobic ("half") pore source term is used to describe the process of hydrophilic pore formation in a lipid bilayer at the gel-liquid phase transition. The source term reflects the occurrence of molecule packing defects in a lipid bilayer at phase transition. The time sequences of the pore formation and closure events are treated as non-stationary, second-order Erlang flows whose characteristics depend on the equation solution.

Physical and computer-based modeling in internal temperature reconstruction by the method of passive acoustic thermometry.

The purpose of this work was to investigate experimentally the capacity of passive acoustic thermometry (PAT) for the reconstruction of 1D, time-variable distributions of the internal temperature. Because in the PAT a noise signal is measured, a considerable integration time (about one minute) is required to attain an acceptable error level (0.5-1K).

Release of Pro-Aggregation Substances from Rabbit Leukocytes Exposed to UV Light: Role of Photo-Induced Apoptosis.

Accumulation of pro-aggregation substances in the incubation medium of isolated UV-irradiated rabbit leukocytes showed stronger correlation with photo-induced apoptotic death of leukocytes (r=0.92) than with their photo-induced necrotic death (r=0.70).

Passive estimation of internal temperatures making use of broadband ultrasound radiated by the body.

The internal temperatures of plasticine models and the human forearm in vivo were determined, based on remote measurements of their intrinsic ultrasonic radiation. For passive detection of the thermal ultrasonic radiation an acoustic radiometer was developed, based on a broadband 0.8-3.

[Lipid pore states in bilayer lipid membranes at phase transition in LiCl solution with addition of polyethylene glycols].

Statistics on open and closed states of the lipid pores was experimentally investigated in planar lipid bilayer membranes from dipalmitoylphosphatidylcholine at the phase transition temperature in LiCl solution (1 M). Polyethylene glycol of different molecular mass was added to the solution. Transmembrane current pulses were measured at voltage-clamp conditions (50 mV).

[Induction of native platelets aggregation by incubation media of the UV irradiated leukocytes: possible role of the photo-induced ADP release].

It is shown that during incubation after UV irradiation (22-24 hours at 7-9 degrees C) irradiated isolated rabbit leukocytes release the compound(s) which induces platelets aggregation in the native platelet rich plasma. Treatment of the incubation media of irradiated leukocytes by heat (5 minutes at 100 degrees C) does not significantly change its pro-aggregation activity. Treatment of the platelet-rich plasma by the incubation media of irradiated leukocytes without stirring induces the refractoriness of platelets to ADP.

[Acoustic thermometry of the patient brain with traumatic brain injury].

Non-invasive deep brain acoustic thermometry is carried out for two patients at Burdenko Neurosurgery Institute. This method is based on the measurements of the own thermal acoustic radiation of the investigated object. These two patients have got the brain injury.

[Variation of vector potential in laboratory conditions changes biological properties of water].

It was found that water preliminary activated with vector potential changes mobility of infusoria, bringing into it, the rate of sugar fermentation in yeast cells and a drinking attractivity of water for mice. It was also shown that water physical parameters changed after water activation: UV absorptions spectrum and a state of a silica admixture. It was supposed that water is the initial target when weak electromagnetic fields have an influence on biological objects.

["Blocking" by polyethyleneglycol of single lipid pores arising in unmodified bilayer lipid membranes during phase transitions].

Changes in the ionic permeability of bilayer lipid membranes from dipalmitoyl phosphatidylcholine at temperatures of phase transition in LiCl (1 M) solution after the addition of polyethyleneglycols of different molecular masses have been studied. The transition of ionic membrane channels from the conducting state to a blocking nonconducting state using polymers makes it possible to calibrate lipid pores. It was shown that low-molecular-weight glycerol, polyethyleneglycols with molecular masses of 300 and 600 decrease the amplitude of fluctuations of the current through the membrane, the decrease being proportional to the size of the polymer molecule being incorporated.

Thermal acoustic radiation from multilamellar vesicles in lipid phase transition.

A new acoustical method for the investigation of lipid phase transition is introduced based on the measurement of the thermal acoustic radiation (TAR) inherent in lipids. The TAR of multilamellar vesicles from dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) was measured in the megahertz range and the variations in the radiation intensity during the lipid phase transition were recorded. Two types of variations are possible: if the temperature of the vesicles decreases (in the process of transition from the liquid crystalline state to the gel state) then the TAR intensity increases, and if the temperature increases (in the reverse transition) then the TAR intensity decreases.

[On measurements of higher harmonics of transmembrane current].

Measurements of higher harmonics of transmembrane current in bilayer lipid membranes from diphytanoyl phosphatidylcholine (DPhPC) in n-decane and n-tetradecane, caused by alternating voltage applied to the membrane, have been conducted. A universal relation between the amplitudes of harmonics was suggested and experimentally checked. This allowed one to calculate the coefficients of expansion of membrane capacity in series with even powers of membrane voltage and to compare the inhomogeneity of membranes from diphytanoyl phosphatidylcholine in n-decane and n-tetradecane with respect to thickness.

[A study of the inhomogeneity of bilayer lipid membranes by measurements of higher harmonics of transmembrane current].

Higher harmonics of alternating current in bilayer lipid membranes caused by sinusoidal voltage applied to the membrane were measured. The bilayer lipid membranes were prepared from diphytanoylphosphatidylcholine in n-decane and n-tetradecane, and measurements were conducted with the aid of an analog-to-digital converter of 16th category. Sinusoidal voltage was formed using a digital-to-analog converter of the 16th category.