A mixture of innate cryoprotectants is key for cryopreservation of a drosophilid fly larva.

Background: Organisms evolved biochemical strategies to cope with environmental stressors. For instance, insects that naturally tolerate internal freezing produce complex mixtures of multiple cryoprotectants (CPs). Better knowledge on composition of these mixtures, and on mechanisms of how the individual CPs interact, could inspire development of laboratory CP formulations optimized for cryopreservation of cells and other biological material. Results: Here we identify and quantify (using high resolution mass spectrometry) a range of putative CPs in larval tissues of a subarctic fly, Chymomyza costata, that survives long-term cryopreservation in liquid nitrogen. The CPs (proline, trehalose, glutamine, asparagine, glycine betaine, glycerophosphoethanolamine, glycerophosphocholine, and sarcosine) accumulate in hemolymph in a ratio of 313:108:55:26:6:4:3:0.5 mmol.L-1. Using calorimetry, we show that the artificial mixtures, mimicking the concentrations of major CPs' in hemolymph of freeze-tolerant larvae, suppress the melting point of water and significantly reduce the ice fraction. We demonstrate in a bioassay that mixtures of CPs administered through the diet act synergistically rather than additively to enable cryopreservation of otherwise freeze-sensitive larvae. Using MALDI-MSI, we show that during slow extracellular freezing of whole larvae trehalose becomes concentrated in partially dehydrated hemolymph and stimulates transition to the amorphous glass phase. In contrast, proline moves to the boundary between extracellular ice and dehydrated hemolymph and tissues where it likely forms a layer of dense viscoelastic liquid. Conclusion: Our results suggest that different components of innate cryoprotective mixtures of freeze-tolerant insect act in synergy during extracellular freezing. We propose that transitions to amorphous glass (stimulated by trehalose) and viscoelastic liquids (having proline as major component) may protect macromolecules and cells from thermomechanical shocks associated with freezing and transfer into and out of liquid nitrogen.

Thermal insulation of autoclaved materials

The construction industry relies on the production of building materials, which are created as a result of particular actions of binding materials widely used in construction, and directly condition the quality of life of a society. Following these thesis, one should create possibilities of conscious choice and use of building materials not only among scientists and constructors, but among the whole society. Two types of additives are used in building materials: additives with a crystalline structure (SiO2) and additives with an amorphous structure (fly ash), which affects the properties and durability of materials. In the last decade industry is also moved on the fight against global warming and overproduction of materials. In May 2019, the level of CO2 concentration in the atmosphere exceeded 415ppm, which was the highest result in the last 50 years. Overproduction is, in turn, associated with the excessive use of natural resources (SiO2) and since 2010 there has been talk of the “sand deficit”. One way to combat overproduction is to use and promote recycling to avoid excess waste. The article describes the method of managing recycled glass sand in autoclaved materials and checking their thermal properties. This study describes the relationship between the physical (thermal isolation), mechanical and microstructural properties of autoclaved materials which undergone hydrothermal treatment and consist of lime (7%) and were modified through the introduction of glass components (up to 90%). For this modification, a certain amount of crystalline SiO2 was replaced with amorphous glass sand. Hydrated calcium silicates are formed in building materials (CaO-SiO2-H2O).

Ultra-Rapid Laser Calorimetry for the Assessment of Crystallization in Low-Concentration Cryoprotectants

Cryoprotective agents (CPAs) are routinely used to vitrify, attain an amorphous glass state void of crystallization, and thereby cryopreserve biomaterials. Two vital characteristics of a CPA loaded system are the critical cooling and warming rates (CCR and CWR), the temperature rates needed to achieve and return from a vitrified state respectively. Due to the toxicity associated with CPAs, it is often desirable to use the lowest concentrations possible, driving up CWR and making it increasingly difficult to measure. This paper describes a novel method for assessing CWR between the 0.4×105-107 °C/min in microliter CPA loaded droplet systems with a new ultra-rapid laser calorimetric approach. Cooling was achieved by direct quenching in liquid nitrogen, while warming was achieved by the irradiation of plasmonic gold nanoparticle-loaded vitrified droplets by a high-power 1064 nm millisecond pulsed laser. We assume "apparent" vitrification is achieved provided ice is not visually apparent (i.e. opacity) upon imaging with a camera during cooling or highspeed camera during warming. Using this approach, we were able to investigate CWR in single CPA systems such as glycerol, PG, and Trehalose in water, and mixtures of glycerol-trehalose-water and propylene glycol-trehalose-water CPA at low concentrations (20-40 wt%). Further, an phenomenological model for determining the CCRs and CWRs of CPA was developed which allowed for predictions of CCR or CWR of single component CPA and mixtures, providing an avenue for optimizing CCR and CWR and perhaps future CPA cocktail discovery.

Effect of Deposition Time On Optical Properties of Chemical Bath Deposited Mercury Sulfide Thin Layers

Mercury sulfide films were deposited on amorphous glass substrates from aqueous solutions by chemical bath deposition method (CBD) at same temperature and different deposition times. Produced layers were post annealed at 250°C about one hour. X-ray diffraction (XRD) was used to study of film’s crystalline structural. Their optical properties were measured by spectrophotometry in the spectra range of 400-850 nm, Kramers-Kronig method was used for the analysis of reflectivity curves of HgS films to obtain the optical constants of films in order to investigation of relation between deposition time and optical properties. According to X-ray diffraction details, all thin films showed crystalline phase with a preferential growth along the (220) planes. Optical results have been shown photolminisance property for HgS produced thin films. By increasing deposition time, the dielectric property, refractive index and band gap values are increased.

Analytical Three-Dimensional Field Ion Microscopy of an Amorphous Glass FeBSi

Three-dimensional field ion microscopy is a powerful technique to analyze material at a truly atomic scale. Most previous studies have been made on pure, crystalline materials such as tungsten or iron. In this article, we study more complex materials, and we present the first images of an amorphous sample, showing the capability to visualize the compositional fluctuations compatible with theoretical medium order in a metallic glass (FeBSi), which is extremely challenging to observe directly using other microscopy techniques. The intensity of the spots of the atoms at the moment of field evaporation in a field ion micrograph can be used as a proxy for identifying the elemental identity of the imaged atoms. By exploiting the elemental identification and positioning information from field ion images, we show the capability of this technique to provide imaging of recrystallized phases in the annealed sample with a superior spatial resolution compared with atom probe tomography.

Microfiller Influence on the Modified Cement Granulometric Composition

The aim of the work is to study the microfiller effect on the granulometric composition of the modified cement. A scanning electron microscope RМ-106 I was used for microscopic analysis. The survey was carried out in reflected electrons. The chemical analysis of the materials’ structure was investigated by energy dispersive spectroscopy (EDS). The distribution of particles of mineral components was evaluated with a Microsizer 201C laser particle analyzer with a range from 0.2 to 600 μm. Microscopic analysis of the samples of microsilica MK-85 shows that all particles are spherical with an average grain size of about 5 microns and consist of amorphous glass with a different set of particle fractions. The results of X-ray phase analysis of condensed microsilica grade MK-85 show that it consists mainly of silicon dioxide in an amorphous form. The introduction of mineral additives with a high specific surface in the composite Portland cements composition in an amount of more than 5% is not rational without the use of superplasticizers, since the water demand increases sharply, which reduces the cement stone strength. The introduction of a microfiller provides an increase in the compressive strength of a cement stone at the age of 28 days of normal hardening by an average of 37%.

ENHANCEMENT IN2S3NANOSTRUCTURES OPTICAL AND ELECTRICAL CHARACTERISTICS USING SPRAY PYROLYSIS GROWTH AS PROMISING MATERIAL FOR OPTOELECTRONIC APPLICATIONS

In the present work, indium sulfide In2S3 thin films were grown on amorphous glass substrate by the chemical spray pyrolysis technique .The different molar ratio of In2S3 powder and thiocyanate ( 0.05,0.1,0.15) M used to grow In2S3 nanostructure with160nm thickness on the glass substrate under 310 Co temperature. Thickness of the films were measured by optical interferometer method. Structural properties were examined using X-Ra diffraction analysis is revealed that all the films were polycrystalline in nature with a dominant 0021peak which indicates that the In2S3 nanostructures are cubic phases. The evaluated crystallite size varied in the range 67.64-81.82nm with the increase of molarity. SEM analysis revealed that all The films have no voids and cracks. Optical properties of the grown films showed that the direct band gap values were found to decrease in the range 3.1-2.75eV which are means that it has the possibility of using indium sulfide in the manufacture of optoelectronic devices. Electrical properties using Hall effect measurement showed that all films N_type semiconductor. the conductivity for all films decreases with increasing of molarity. Results indicates the possibility of using indium sulfide in the manufacturing of detector or a gas sensor.

Sulfophosphate Glass Doped with Er3+ and TiO2 Nanoparticles: Thermo-Optical Characterization by Photothermal Spectroscopy

In this work, time-resolved thermal lens and beam deflection methods were applied to determine the thermo-optical properties of Er3+ doped sulfophosphate glass in which different concentrations of Titanium dioxide (TiO2) nanoparticles (NPs) were embedded. Thermal diffusivity (D), thermal conductivity (κ), and the temperature coefficient of the optical path length (ds/dT) were determined as a function of NPs concentrations. Moreover, the growth of TiO2 NPs inside the amorphous glass matrix was evidenced by Transmission Electron Microscopy (TEM) images as well as through optical effects such as refractive index change of the glass. The outcomes indicated relatively high values for D and κ as well as a low ds/dT as required for most optical components used for laser media. The addition of TiO2 NPs with concentration of dopants up to 0.6 mol% improved the optical properties of the glass samples but did not affect its thermal properties. The results indicate that the enhanced optical and thermal performance of the proposed co-doped glass fits the quality standards for materials used in photonic devices.

Synthesis and Properties of p-Si/n-Cd1−xAgxO Heterostructure for Transparent Photodiode Devices

We developed silver-doped Cd1–xAgxO thin films (where x = 0, 0.01, 0.02, 0.03 and 0.04) on amorphous glass substrate by an automated nebulizer spray pyrolysis set-up. The XRD patterns show rock salt cubic crystal structures, and the crystallite sizes vary with respect to Ag doping concentrations. SEM images exhibited a uniform distribution of grains with the addition of Ag; this feature could support the enhancement of electron mobility. The transmittance spectra reveal that all films show high transmittance in the visible region with the observed bandgap of about 2.40 eV. The room temperature photoluminescence (PL) studies show the increase of near-band-edge (NBE) emission of the films prepared by different Ag doping levels, resulting in respective decreases in the bandgaps. The photodiode performance was analyzed for the fabricated p-Si/n-Cd1–xAgxO devices. The responsivity, external quantum efficiency and detectivity of the prepared p-Si/n-Cd1–xAgxO device were investigated. The repeatability of the optimum (3 at.% Ag) photodiode was also studied. The present investigation suggests that Cd1–xAgxO thin films are the potential candidates for various industrial and photodetector applications.