Nanomotion of bacteria to determine metabolic profile

In addition to their visible motion such as swimming(e.g.,with the help offlagella),bacteria can also exhibit nanomotion that is detectable only with highly sensitive instruments,and this study shows that it is possible to detect bacterial nanomotion using an AFM detection system.The results show that the nanomotion characteristics depend on the bacterial strain,and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium.

Brain Urea as a Potential Biomarker of Neoplasm Progression

Metabolic reprogramming is a key feature driving oncogenesis in cancers. Recent studies have revealed that protein metabolism is largely altered in gliomas facilitating its malignant growth. Urea is the end product of nitrogen metabolism which is mainly produced by arginase. The interdependence of arginase and other biochemical mechanisms triggered scientific research interest. This research aimed to investigate the relationships between the urea as the main parameter of protein metabolism and glioma progression. It was also the most pronounced relationship between urea and the level of the nuclear protein Ki-67 as a marker of proliferative activity and O-6-methylguanine-DNA methyltransferase (MGMT), which performs DNA repair. Postoperative material from 20 patients with gliomas of different grades of anaplasia was analyzed.

Generation of synchronized x-rays and mid-infrared pulses by Doppler-shifting of relativistically intense radiation from near-critical-density plasmas

It is shown that when relativistically intense ultrashort laser pulses are reflected from the boundary of a plasma with a near-critical density,the Doppler frequency shift leads to generation of intense radiation in both the high-frequency(up to the x-ray)and low-frequency(mid-infrared)ranges.The efficiency of energy conversion into the wavelength range above 3μm can reach several percent,which makes it possible to obtain relativistically intense pulses in the mid-infrared range.These pulses are synchronized with high harmonics in the ultraviolet and x-ray ranges,which opens up opportunities for high-precision pump–probe measurements,in particular,laser-induced electron diffraction and transient absorption spectroscopy.

Strain-Rate Dependency of a Unidirectional Filament Wound Composite under Compression

This article presents the results of experimental studies concerning the dynamic deformation and failure of a unidirectional carbon fiber reinforced plastic(T700/LY113)under compression.The test samples were manufactured through the filament winding of flat plates.To establish the strain rate dependencies of the strength and elastic modulus of the material,dynamic tests were carried out using a drop tower,the Split Hopkinson Pressure Bar method,and standard static tests.The samples were loaded both along and perpendicular to the direction of the reinforcing fiber.The applicability of the obtained samples for static and dynamic tests was confirmed through finite elementmodeling and the high-speed imaging of the deformation and failure of samples during testing.As a result of the conducted experimental studies,static and dynamic stress-strain curves,time dependencies of deformation and the stress and strain rates of the samples during compression were obtained.Based on these results,the strain rate dependencies of the strength and elasticity modulus in the strain rate range of 0.001-6001/s are constructed.It is shown that the strain rate significantly affects the strength and deformation characteristics of the unidirectional carbon fiber composites under compression.An increase in the strain rate by 5 orders of magnitude increased the strength and elastic modulus along the fiber direction by 42%and 50%,respectively.Perpendicular loading resulted in a strength and elastic modulus increase by 58%and 50%,respectively.The average strength along the fibers at the largest studied strain rate was about 1000MPa.The obtained results can be used to design structural elements made of polymer composite materials operating under dynamic shock loads,as well as to build models of mechanical behavior and failure criteria of such materials,taking into account the strain rate effects.

In vivo real-time monitoring delayed administration of M2 macrophages to enhance healing of tendon by NIR-II fluorescence imaging

The administration time is a critical but long-neglected point in cell therapy based on macrophages because the incorrect time of macrophage administration could result in diverse outcomes regarding the same macrophage therapy.In this work,the second near-infrared(NIR-II)fluorescence imaging in vivo tracking of M2 macrophages during a pro-healing therapy in the mice model of rotator cuff injury revealed that the behavior of administrated macrophages was influenced by the timing of their administration.The delayed cell therapy(DCT)group had a longer retention time of injected M2 macrophages in the repairing tissue than that in the immediate cell therapy(ICT)group.Both Keller-Segel model and histological analysis further demonstrated that DCT altered the chemotaxis of M2 macrophages and improved the healing outcome of the repaired structure in comparison with ICT.Our results offer a possible explanation of previous conflicting results on reparative cell therapy and provoke reconsideration of the timing of these therapies.

Plant hormesis and Shelford’s tolerance law curve

Shelford’s law of tolerance is illustrated by a bell-shaped curve depicting the relationship between environmental factor/factors’intensity and its favorability for species or populations.It is a fundamental basis of ecology when considering the regularities of environment impacts on living systems,and applies in plant biology,agriculture and forestry to manage resistance to environmental limiting factors and to enhance productivity.In recent years,the concept of hormesis has been increasingly used to study the dose-response relationships in living organisms of different complexities,including plants.This requires the need for an analysis of the relationships between the hormetic dose-response model and the classical understanding of plant reactions to environments in terms of Shelford’s law of tolerance.This paper analyses various dimensions of the relationships between the hormetic model and Shelford’s tolerance law curve under the influence of natural environmental factors on plants,which are limiting for plants both in deficiency and excess.The analysis has shown that Shelford’s curve and hormetic model do not contradict but instead complement each other.The hormetic response of plants is localized in the stress zone of the Shelford’s curve when adaptive mechanisms are disabled within the ecological optimum.At the same time,in a species range,the ecological optimum is the most favorable combination of all or at least the most important environmental factors,each of which usually deviates slightly from its optimal value.Adaptive mechanisms cannot be completely disabled in the optimum,and hormesis covers optimum and stress zones.Hormesis can modify the plant tolerance range to environmental factors by preconditioning and makes limits of plant tolerance to environmental factors flexible to a certain extent.In turn,as a result of tolerance range evolution,quantitative characteristics of hormesis(width and magnitude of hormetic zone)as well as the range of stimulating doses,may significantly differ in various plant species and even populations and intra-population groups,including plants at different development stages.Using hormetic preconditioning for managing plant resistance to environmental limiting factors provides an important perspective for increasing the productivity of woody plants in forestry.

生态与分布类型在俄罗斯古北区蝉亚族区系研究中的应用(半翅目:蝉科:蝉亚族)(英文)

本文综述了生态类型学(如温度、湿度、植物生境、生物形态等)和分布类型学(如带、域、区等)在古北区蝉亚族研究中的应用。

Associative Space-Time Sedenions and Their Application in Relativistic Quantum Mechanics and Field Theory

We present an alternative sixteen-component hypercomplex scalar-vector values named “space-time sedenions”, generating associative noncommutative space-time Clifford algebra. The generalization of relativistic quantum mechanics and field theory equations based on sedenionic wave function and space-time operators is discussed.

Resistive Switching in Stabilized Zirconia Films Studied by Conductive Atomic Force Microscopy

We have applied Conductive Atomic Force Microscopy (CAFM) to study the microscopic mechanism of resistive switching in the ultrathin (3 - 5 nm) yttria stabilized zirconia (YSZ) films. Using CAFM, we were able to trace the growth of the individual conductive filaments, which are considered now to be responsible for the resistive switching effect in the transition metal oxides. The growth of the filaments has been proven to be initiated by the defects in the film material including the ones, which are the concentrators of the electric field, in particular, by the roughness (hillocks) of the film/substrate interface. The electron transport via individual filaments has been studied. Besides the butterfly-type hysteresis in the current-voltage (I-V) curves of the probe- to-sample contact typical for the bipolar resistive switching, we have observed the I-V curves with resonant peaks attributed to the resonant electron tunneling via the localized electron states in the filaments.

Wireless Infrared Pyrometer with Fiber Optic: Construction and Processing Algorithms

In this paper, developed wireless portable infrared pyrometer with dual channel fiber optic is described. The pyrometer measures surface temperature in wide infrared spectral range of 2 - 25 um. A data processing algorithm based on the methods of synchronous detection providing

BDNF Overexpression Enhances the Preconditioning Effect of Brief Episodes of Hypoxia,Promoting Survival of GABAergic Neurons

Hypoxia causes depression of synaptic plasticity,hyperexcitation of neuronal networks,and the death of specific populations of neurons.However,brief episodes of hypoxia can promote the adaptation of cells.Hypoxic preconditioning is well manifested in glutamatergic neurons,while this adaptive mechanism is virtually suppressed in GABAergic neurons.Here,we show that brain-derived neurotrophic factor(BDNF) overexpression in neurons enhances the preconditioning effect of brief episodes of hypoxia.The amplitudes of the NMDAR-and AMPARmediated Ca2+ responses of glutamatergic and GABAergic neurons gradually decreased after repetitive brief hypoxia/reoxygenation cycles in cell cultures transduced with the(AAV)-Syn-BDNF-EGFP virus construct.In contrast,the amplitudes of the responses of GABAergic neurons increased in non-transduced cultures after preconditioning.The decrease of the amplitudes in GABAergic neurons indicated the activation of mechanisms of hypoxic preconditioning.Preconditioning suppressed apoptotic or necrotic cell death.This effect was most pronounced in cultures with BDNF overe xpression.Knockdown of BDNF abolished the effect of preconditioning and promoted the death of GABAergic neurons.Moreover,the expression of the anti-apoptotic genes Stat3,Socs3,and Bcl-x1 substantially increased 24 h after hypoxic episodes in the transduced cultures compared to controls.The expression of genes encoding the pro-inflammatory cytokines IL-10 and IL-6 also increased.In turn,the expression of pro-apoptotic(Bax,Casp-3,and Fas) and proinflammatory(IL-1β and TNFα) genes decreased after hypoxic episodes in cultures with BDNF overexpression.Inhibition of vesicular BDNF release abolished its protective action targeting inhibition of the oxygen-glucose deprivation(OGD)-induced [Ca2+]i increase in GABAergic and glutamatergic neurons,thus promoting their death.Bafilomycin A1,Brefeldin A,and tetanus toxin suppressed vesicular release(including BDNF) and shifted the gene expression profile towards excitotoxicity,inflammation,and apoptosis.These inhibitors of vesicular release abolished the protective effects of hypoxic preconditioning in glutamatergic neurons24 h after hypoxia/reoxygenation cycles.This finding indicates a significant contribution of vesicular BDNF release to the development of the mechanisms of hypoxic preconditioning.Thus,our results demonstrate that BDNF plays a pivotal role in the activation and enhancement of the preconditioning effect of brief episodes of hypoxia and promotes tolerance of the most vulnerable populations of GABAergic neurons to hypoxia/ischemia.

Resolution and contrast enhancement of laser-scanning multiphoton microscopy using thulium-doped upconversion nanoparticles

High-contrast optical imagi ng is achievable using phosphoresce nt labels to suppress the short-lived background due to the optical backscatterand autofluoresce nee.However,the long-lived phosphorescence is generally incompatible with high-speed laser-scan ning imaging modalities.Here,we show that upc on versi on nan oparticles of structure NaYF4:Yb co-doped with 8%Tm(8T-UCNP)in combi nation with a commerciallaser-scanning multiphoton microscopy are uniquely suited for labeling biological systems to acquire high-resolution images with the enhancedcon trast.In comparison with many phosphoresce nt labels,the 8T-UCNP emission lifetime of-15μs affords rapid image acquisition.Thehigh-order optical nonlinearity of the 8T-UCNP(n=4,as confirmed experimentally and theoretically)afforded pushing the resolution limitattain able with UCNPs to the diffraction-limit.The contrast enha nceme nt was achieved by suppressing the backgro und using(i)ban dpassspectral filtering of the narrow emission peak of 8T-UCNP at 455-nm,and(ii)time-gating implemented with a time-correlated single-photon counting system that demonstrated the contrast enhancement of>2.5-fold of polyethyle neimine-coated 8T-UCNPs take n up by huma nbreast adeno carcinoma cells SK-BR-3.As a result,discrete 8T-UCNP nan oparticles became clearly observable in the freshly excised splee ntissue of laboratory mice 15-min post in trave nous injectio n of an 8T-UCNP solution.The dem on strated approach paves the way forhigh-contrast,high-resoluti on,and high-speed multiphot on microscopy in challe nging envir onments of i ntense autofluorescence,exogenous staining,and turbidity,as typically occur in intravital imaging.

A review on magneto-optical ceramics for Faraday isolators

As a promising magneto-optical(MO)material applied in Faraday isolators,magneto-optical ceramics possess excellent comprehensive properties and have attracted much attention these years.Herein,we review the fabrication and properties of magneto-optical ceramics including garnet,sesquioxide,and A_(2)B_(2)O_(7) ceramics.Some of the ceramics have been proved to possess applicable performance,while further studies are still needed for most of the magneto-optical ceramics.Aiming at the application for isolators,the research status,existing problems,and development trends of magneto-optical ceramics are shown and discussed in this review.

IR-transparent MgO-Gd_(2)O_(3) composite ceramics produced by self-propagating high-temperature synthesis and spark plasma sintering

A glycine–nitrate self-propagating high-temperature synthesis(SHS)was developed to produce composite MgO-Gd_(2)O_(3) nanopowders.The X-ray powder diffraction(XRD)analysis confirmed the SHS-product consists of cubic MgO and Gd_(2)O_(3) phases with nanometer crystallite size and retains this structure after annealing at temperatures up to 1200℃.Near full dense high IR-transparent composite ceramics were fabricated by spark plasma sintering(SPS)at 1140℃and 60 MPa.The in-line transmittance of 1 mm thick MgO-Gd_(2)O_(3) ceramics exceeded 70%in the range of 4–5 mm and reached a maximum of 77%at a wavelength of 5.3 mm.The measured microhardness HV0.5 of the MgO-Gd2O3 ceramics is 9.5±0.4 GPa,while the fracture toughness(KIC)amounted to 2.0±0.5МPa·m1/2.These characteristics demonstrate that obtained composite MgO-Gd_(2)O_(3) ceramic is a promising material for protective infra-red(IR)windows.

Hydrogel scaffolds based on blood plasma cryoprecipitate and collagen derived from various sources: Structural, mechanical and biological characteristics

At present there is a growing need for tissue engineering products,including the products of scaffold-technologies.Biopolymer hydrogel scaffolds have a number of advantages and are increasingly being used to provide means of cell transfer for therapeutic treatments and for inducing tissue regeneration.This work presents original hydrogel biopolymer scaffolds based on a blood plasma cryoprecipitate and collagen and formed under conditions of enzymatic hydrolysis.Two differently originated collagens were used for the scaffold formation.During this work the structural and mechanical characteristics of the scaffold were studied.It was found that,depending on the origin of collagen,scaffolds possess differences in their structural and mechanical characteristics.Both types of hydrogel scaffolds have good biocompatibility and provide conditions that maintain the three-dimensional growth of adipose tissue stem cells.Hence,scaffolds based on such a blood plasma cryoprecipitate and collagen have good prospects as cell carriers and can be widely used in regenerative medicine.