Test Tube Research Articles

Light-triggered reactions in a new “light” of nanoparticles engineering

This study presents an innovative light-triggered synthesis of nanoparticles (NPs) utilizing UV radiation (λ = 254 nm), thiols (non-toxic mercaptosuccinic acid, MSA), and metal ions (Cu2+, Zn2+, Cd2+, Se4+). Efficient formation of various nanoparticles is achieved by exposing a precursor blend of metal ions and thiols (MSA) to ultraviolet light in compact volumes, like UV-transparent 96-well plates (50 – 300 μL per well) or plastic tubes (1.5 – 50 mL). This process effectively produces different types of nanoparticles, including fluorescent zinc-cadmium quantum dots (ZnCd QDs), non-fluorescent copper nanoparticles (CuNPs), and selenium nanoparticles (SeNPs). The scalability of the method allows for easy upscaling using larger test tubes or downsizing by depositing precursors (10 – 100 μL) on a paper matrix, where UV treatment not only induces NP formation in solution but also facilitates their anchoring to the paper surface. The developed one-pot in situ approach offers a cost-effective, user-friendly, and energy-efficient method for NP production and chemical engineering on paper surfaces. The technique is promising for a wide range of applications, such as interferometric measurement using ZnCd QDs, bactericidal effects of CuNPs against methicillin-resistant Staphylococcus aureus (MIC100 = 0.14 mg/mL), and visible light switchable (ON/OFF) nanozymatic reactors employing SeNPs. We suggest light-triggered chemistry based on thiols and metal ions for effective “soft” synthesis of various nanoparticles and NPs-based devices.

Colloidal interaction of fly ash and soil clay

The combustion of coal worldwide creates a large quantity of fly ash (FA), and the application of FA to agricultural soils is being encouraged as a resource utilization strategy. While most of our attention has focused on positive aspects such as nutrient supplementation and pollution mitigation, the negative impacts of FA have likely been overlooked. In this study, we examined the colloidal properties of FA and soil clay, aiming to demonstrate the ability of FA to increase the dispersibility and transportability of soil clay. Dynamic light scattering technique was coupled with the test tube method to track the kinetics and pH-dependent changes in the zeta potential, hydrodynamic size and colloidal stability of FA, soil clay and their mixtures. We found that FA occurred in solution as “negatively charged balls”, and its negative surface charges increased with increasing pH. FA itself showed a low dispersibility; however, FA became more dispersive when it was introduced to clay suspensions. The mechanism is that the introduction of FA supplied more negative charges to the clay suspension, inducing electrostatic repulsion with soil clay, from which both FA and soil clay were favoured to disperse. Therefore, it can be inferred that off-site transport of FA is possible. More importantly, excessive application of FA can inadvertently intensify clay dispersibility, eventually resulting in soil clays together with FA being more vulnerable to leaching and/or surface run-off erosion. This suggests that the application of FA needs more careful consideration, and the development of more suitable techniques for the sustainable application of FA is still needed.

Investigating the Status of Contamination With Pulex irritans and Xenopsylla cheopis in Pets, Guard and Stray Dogs in Tabriz, Iran

Introduction: Fleas are the most prevalent ectoparasites indoors and outdoors due to their high reproductive rate, ability to feed on different hosts, and the unpleasant effects of their bites. Methods: This study was conducted on 360 dogs in and around Tabriz to find the rate and type of human flea contamination in these dogs, which were divided into three categories: pets, guards, and stray dogs. After fleas were identified in the dogs’ skin, they were taken with glue and fixed on the slide with glue. When the number of fleas was large, the captured fleas were transported to a test tube and treated with 70% alcohol. Dehydration of fleas was performed with ascending percentages of ethanol from 50 to 100% absolute and was kept inside each alcohol percentage for 10 to 20 minutes. Results: Regarding the dogs studied in this research, the rate of actual contamination in guard dogs was 76.67% (92 dogs were contaminated with flea feces). However, 74 dogs (about 15%) were infested with different fleas. Unfortunately, the rate of contamination in stray dogs was 100%. The rate of real contamination based on the separation of fleas and flea excrement from the body of this group of dogs was equal. The rate of flea infestation in pet dogs was 14 out of 100 dogs, representing 14% contamination. Conclusion: It should be acknowledged that, unfortunately, flea infestation is expected in the region’s dogs, depending on the type of dogs kept. Infestation with these insidious skin parasites with varying rates and symptoms is common, which, in addition to the economic damage of spending time and money on medicine for disease in animals, causes environmental pollution, increases the likelihood of disease transmission by these parasites, and increases the possibility of human infection and disease transmission from them to humans, as well as environmental pollution.

Abstract LB036: Back and forth from structure to functional target: The interplay between Vimentin and non-canonical nucleic acid arrangements

Abstract Vimentin, a member of type III intermediate filaments (IFs), is a cytoskeletal protein that covers multiple architectural and functional roles, including the maintenance of organelle positioning in the cytoplasm, the regulation of cytoskeletal rearrangements, while more recently its potential involvement as a regulatory factor in gene expression emerged. Additionally, it is involved in cell migration and epithelial-to-mesenchymal transition (EMT). In previous works, we identified Vimentin as the first known protein that selectively binds G-quadruplexes repeats (G4-repeats). This DNA folding consists of repeated units of nucleic acid sequences arranged into G-quadruplex (G4s). Their three-dimensional features largely differ from the most common single-stranded or double-helix nucleic acids as well as from the isolated G4 modules. Noteworthy, they occur at a small subset of genomic sites, associated with cell proliferation and migration, where they can recruit the soluble nuclear pool of Vimentin. Altogether, this information led us to consider the Vimentin-DNA complex as a promising target for developing small molecule binders capable of inhibiting cell migration and, eventually, EMT. To properly set up a rational drug-design approach, we integrated different advanced biophysical tools (Hydrogen-Deuterium Exchange, Cryo-Electron Microscopy) to derive a comprehensive picture of the protein-DNA complex at the molecular level. This approach allowed us to map the interaction surface between the soluble tetrameric form of Vimentin and a G4-repeat. Based on this data, we initiated a screening campaign using focused libraries of small molecules and peptides, which were rationally designed according to the structural features of the Vimentin-G4-repeats complex. The capability of the identified hits to prevent the recognition of the nucleic acid by Vimentin has been investigated This approach allowed us to identify attractive novel entities that prevent the Vimentin-G4-repeat complex formation according to different molecular mechanisms. These systems are now under further refinement moving from the test tube to the cellular environment, where the dynamic behavior of these nucleic acid domains as well as the recruitment of different proteins by Vimentin might alter the architectural features of the target.

To Estimate and Compare the Level of Serum Immunoglobulin A in Patients of Oral Submucous Fibrosis, Leukoplakia, and Control Group.

To estimate and compare the level of serum immunoglobulin A in patients of oral submucous fibrosis (OSMF), leukoplakia, and control group. OSMF is a well-recognized potentially malignant condition in the oral cavity, and a transformation rate as high as 7.6% over a period of 10 years has been reported from India. Leukoplakia has evolved as a clinico-pathologic concept over many years, with the current clinical designation being accepted worldwide. Quantia IgA is a turbidometric immunoassay for the detection of IgA in human serum and is based on the principle of agglutination reaction. The test specimen is mixed with the activation buffer (R1) and then with antihuman IgA reagent (R2) and allowed to react. For the estimation of serum IgA, 500 μl of Quantia IgA activation buffer R1 is taken in a clean test tube. Serum sample is diluted in the ratio of 1:5 with normal saline. Ten microliters of diluted serum sample are added to R1. After incubation for 10 min, 50 μl of R2 is added, which is Quantia IgA antihuman IgA reagent to the sample, and the reading is recorded at wavelength 340 nm at 37°C. The level of IgA will be estimated by a semi-automatic biochemical analyzer machine and then data analysis will be done. The immunologic alterations observed by us in OSMF and leukoplakia are almost similar or nearer to the alterations observed in oral cancer, so it is reasonable to assume that OSMF and leukoplakia can be an intermediate stage in the transformation process of a normal cell to oral malignancy. Prevention and early detection is the best way to reduce the incidence and mortality of premalignant disorders and oral cancer. There are many ways and methods of early detection of premalignant disorders and oral cancer, and the immunological method is one of them.

Antibacterial Effect of Nanoparticles Synthesized from Ficus exaseprata (Sandpaper Leaves)

The eco-friendly, cost effectiveness, and the less toxic nature of synthesized green nanoparticles to the environment have become a global attraction to many studies. The study aim to synthesize Silver (Ag) nanoparticles from Ficus exasperata (Sandpaper leave) leaves and to determine its antimicrobial effect on bacteria isolates. Silver (Ag) nanoparticles were synthesized from the plant extracts using standard extracting techniques and their presence was verified and confirmed using an ultraviolet-visible (UV-Vis) Spectrophotometer. A prepared series of silver nitrate (AgNO3) solutions were mixed with the plant extracts at a ratio of 1:1 (v/v) to a total volume of 20ml in a text-tube. The test tubes were rapped with aluminum foil and heated in a water bath at 60OC for 3 hours and allowed to cool and analyzed using UV-Vis Spectrophotometer. The UV-Vis spectra confirmed the different concentrations of silver nitrate (AgNO3) that produced Ag nanoparticles and their average size was more than 50nm and less than 100nm. The mixture of the leave extract was tested for its antimicrobial activity against gram-positive and gram-negative organisms such as Staphylococcus aureus Bacillus cereus and Escherichia coli respectively. The results showed that the growth of the different bacteria was inhibited by the extracts containing silver nitrate on Staphylococcus aureus and Escherichia coli and not on Bacillus cereus using Ficus exaseprata nanoparticles. Statistical evaluation showed that zones of inhibition on the three bacteria produced by the aqueous leave extracts containing different concentration of silver nitrate (AgNO3¬¬) precursor was significantly different from the silver nitrate (AgNO3) precursor. It were observed that the higher the concentration of the silver nitrate (AgNO3) the greater the zone of inhibition. It can be concluded that Ficus exaseprata leave extracts dope with silver nanoparticles, can produce antimicrobial effects on some microorganisms.

Research on the R513A condensation heat transfer characteristics in horizontal microfin tubes

R513A has been proposed as alternative to R134a due to its lower GWP. So, it is necessary to investigate the condensation heat transfer characteristics and pressure drop of R513A in the horizontal tubes. The 12.70-mm-OD and 9.52-mm-OD tubes were selected for condensation tests. It was found that the R134a condensation heat transfer coefficient in the 12.70-mm-OD microfin tube was similar to the R513A condensation heat transfer coefficient, and the deviation was about −3% ∼ +9%; R513A yielded 4.44% ∼ 16.01% lower pressure drop than R134a. The R513A heat transfer coefficient of the microfin tube was about 1.42–1.74 times of that of the smooth tube, and the pressure drop was 39.11% ∼ 76.63% than that in the smooth tube. Additionally, the condensation heat transfer coefficient and pressure drop of the 9.52-mm-OD test tube were 23.88% ∼ 41.62% and 40.79% ∼ 71.86% higher than those of the 12.70-mm-OD tube, respectively. The micro-fin structure inside the microfin tube resulted in efficient heat transfer, but also increased the fluid flow power consumption. Moreover, as the tube diameter decreased, the effects of sheer stress and surface tension increased. Furthermore, experimental data were also compared with previous correlations proposed for microfin tubes. More experiments are still required to develop more applicable theoretical correlations in future.

Thrombus discrimination with electron density: potential implications for non-contrast computed tomography imaging.

The potential clinical usefulness of electron density (ED) imaging, that can be directly estimated using dual-layer spectral computed tomography (CT), has been poorly investigated. We explored whether ED imaging might improve thrombus identification compared to conventional imaging in vitro. We evaluated mechanical thrombectomy material obtained from patients with acute ischemic stroke (AIS) treated in a tertiary level stroke center and immediately fixed in 10% neutral buffered formalin and stored in polystyrene test tubes. The test tubes were immersed in a bucket of water for evaluation by spectral CT, along with scattered control tubes. All images were obtained using a dual-layer detector CT scanner. Each tube was assessed using multiparametric side-by-side view of conventional CT (120 kVp), low monoenergetic imaging (40 keV), and ED images. Fifty-eight polystyrene tubes were analyzed, comprising 52 tubes with thrombectomy material of at least 1 mm2 size obtained from 52 AIS patients, and six control tubes filled with formalin. ED imaging identified accurately the presence of material in all tubes, whereas 2 (3%) of the tubes containing thrombus were not identified by conventional CT, leading to a very good agreement between observers for the presence of material using conventional CT and ED imaging (kappa =0.84, P<0.001). Using ED imaging, thrombus material showed a mean density of 108.8±2.9 percent ED relative to water (%EDW), water had a mean density of 100.0±0.3 %EDW, and formalin a mean density of 103.5±1.2 %EDW. Compared to conventional imaging and 40 keV monoenergetic, ED imaging had a significantly higher signal-to-noise ratio (conventional 10.4±7.0, vs. 40 keV 11.5±8.4, vs. ED 490.0±304.5, P<0.001) and contrast-to-noise ratio (CNR) (conventional 4.3±4.3, vs. 40 keV 5.7±11.2, vs. ED 37.8±29.1, P<0.001). In this in-vitro study, we demonstrated improved visualization of thrombus with ED imaging compared to conventional imaging and low monoenergetic imaging, with a significant increase in CNR.

BOLD: Color from Test Tube to Textile

Abstract Red can be the color of passion and danger, or luck and prosperity. Blue can be the shade of sadness—singing the blues—or a sign of tranquility and serenity. As the Russian painter Wassily Kandinsky once affirmed, in his 1911 treatise Concerning the Spiritual in Art , “Color is a power which directly influences the soul.” Color is also culture: we’ve colored our environments, clothes, and bodies for thousands of years, since early humans applied simple organic stains derived from the plants around them. The art and science of dyeing is an ancient one; today it’s an economic and commercial powerhouse. The arrival of the first synthetic dyes in the 1850s—discovered by happenstance from experiments with coal tar waste—brought us a rainbow of new possibilities for fashion and textiles, from color “fads” and trends to new means for self-expression. But synthetic color’s dark side lingers in polluted waterways. A new exhibit at the museum of the Science History Institute explores these complex legacies. Bold: Color From Test Tube To Textile takes visitors on a colorful 150-year journey through the history of synthetic dyes, examining the people and places who’ve shaped our modern understanding of color—from the laboratory to the factory floor, from the runway to retail, and beyond.

Determination of the Optimum Test Conditions for Measurement of Glucose Level in Liquids

Diabetes is a disease that affects more than 400 million people worldwide and currently lacks a cure. Monitoring blood sugar levels is crucial in minimizing the effects of this disease and protecting against its complications. Invasive and minimally invasive methods are commonly used traditional approaches for detecting and monitoring blood sugar levels. However, these methods bring along psychological and infectious risks. Currently, efforts are being made to develop a non-invasive method for determining blood sugar levels. Microwaves offer the possibility of non-invasive glucose measurement as they do not cause any harmful effects on human tissue. Furthermore, the complex permeability of blood is sensitive to glucose concentration in the microwave band. In literature, most of the studies are done with vector network analyzers (VNA) to detect blood sugar level noninvasively. In this study, an expensive and bulky VNA is replaced by an affordable microwave source and RMS power detector. The influence of the type and diameter of the test tube material used for non-invasive determination of sugar levels is examined with this setup. Additionally, the effect of the distance between the Vivaldi antennas used during measurements and the test tube is investigated. The results indicate that measurements performed using plastic test tubes yield better results compared to glass test tubes. Moreover, reducing the diameter of the test tube leads to improved outcomes. It has been observed that accurate results cannot be obtained if the antennas and the test tube are too close (4.5cm) from each other.

УСОВЕРШЕНСТВОВАНИЕ ПРИЕМОВ ПЕРЕВОДА ОЗДОРОВЛЕННЫХ IN VITRO ВИНОГРАДНЫХ РАСТЕНИЙ В УСЛОВИЯ ПОЧВЕННОЙ КУЛЬТУРЫ

The article discusses techniques for improving the properties of a nutrient substrate used for planting healthy in vitro grape plants. The research was carried out on the basis of the laboratory of biotechnology ARRIV&amp;W – branch of FSBSI FRARC on an interspecific hybrid Krasnostop Carpi. The purpuse of the study is to improve the ways of adapting healthy in vitro plants to non–sterile conditions. With microclonal reproduction of grapes, death most often occurs when transferring test tube plants to non-sterile conditions. The selection of the composition of the soil substrate and the improvement of its water-physical and biological properties helps to reduce the risk of plant death. In our studies, peat, garden soil and river sand (1:1:1) were used as part of the substrate, to which “Aquasin hydrogel” and “Trichoderma Veride” endomycorrhizal preparation containing mycelium and spores of Trichoderma viride fungi, strain 471, were added. The plants were planted in a 500 ml container, had been adapted to non-sterile conditions and had been grown for 90 days on racks of accelerated plant cultivation (RAPC). In the process, the indicators of the preservation of initial plants, their growth, development and spread of the root system were noted. As a result, it can be concluded that the combined use of hydrogel and mycorrhiza ensures the best survival and preservation of plants of the Krasnostop Carpi variety. The mycorrhizal preparation promotes better development of the leaf surface, and the addition of hydrogel ensures better development of the root system, which will provide plants with better survival in open ground conditions of the basic mother plantation. Key words: HEALTHY IN VITRO GRAPES, HYDROGEL, MYCORRHIZA, SUBSTRATE, ADAPTATION TO NON-STERILE CONDITIONS

Recent advances in enzyme-free and enzyme-mediated single-nucleotide variation assay in vitro.

Single-nucleotide variants (SNVs) are the most common type variation of sequence alterations at a specific location in the genome, thus involving significant clinical and biological information. The assay of SNVs has engaged great awareness, because many genome-wide association studies demonstrated that SNVs are highly associated with serious human diseases. Moreover, the investigation of SNV expression levels in single cells are capable of visualizing genetic information and revealing the complexity and heterogeneity of single-nucleotide mutation-related diseases. Thus, developing SNV assay approaches in vitro, particularly in single cells, is becoming increasingly in demand. In this review, we summarized recent progress in the enzyme-free and enzyme-mediated strategies enabling SNV assay transition from sensing interface to the test tube and single cells, which will potentially delve deeper into the knowledge of SNV functions and disease associations, as well as discovering new pathways to diagnose and treat diseases based on individual genetic profiles. The leap of SNV assay achievements will motivate observation and measurement genetic variations in single cells, even within living organisms, delve into the knowledge of SNV functions and disease associations, as well as open up entirely new avenues in the diagnosis and treatment of diseases based on individual genetic profiles.

A Study of A1 and A2 Subtypes Among Whole-Blood Donors With Blood Groups A and AB at the Blood Center of a Tertiary Care Institute in Chhattisgarh.

The ABO blood group shows various subtypes due to the heterogeneity of A and B alleles. The frequency of these subtypes varies in different populations. Studies related to the frequency of subtypes of blood groups A and AB are lacking in this region. So, we planned this study to estimate the prevalence of A1and A2 subtypes among the healthy blood donor population. This was a prospective study performed in the blood center of a teaching hospital in the Chhattisgarh state. Healthy whole-blood donors were included in the study after written informed consent. The conventional test tube method was used for performing forward and reverse blood grouping. Testing with anti-A1 and anti-H lectin was performed in blood groups A and AB. Additional tests such as saliva testing for secretor status and adsorption-elution were performed if needed. Four thousand one hundred twelve donor samples were studied, out of which 1170 showed A antigen. Among 1170 samples, 74.6% were blood group A, and 25.4% were AB. Among blood group A, 92.3% were A1and 3.3% A2,and the rest were other subtypes, while in AB, it was 85.2% A1B and 14.8% A2B. Two cases of anti-A1 antibodies were also noted, which were clinically insignificant. We observed a significantly higher proportion of A2B than A2 in our study population. We also found a large proportion of Aint in the study participants. Testing with anti-A1 andanti-H lectin is recommended in blood groups A and AB to determine various subtypes and prevent any incompatibility.

Development of biopolymer based colorimetric indicator for monitoring of meat and fish freshness

The need to extend food products' shelf lives is growing as a result of efforts to cut expenses and minimize food waste. The food industry is interested in solutions that would make it easy to keep food fresh and safe for as long as the product is on sale. The purpose of the study is to develop a biopolymer-based colorimetric indicator for monitoring of meat and fish freshness. The significance of the research is to provide food safety via control of the freshness using green and cheap methods. The objects of the study are natural and artificial indicators. The paper presents natural indicators such as curcumin, pomegranate, beetroots, and carrot juice which were incorporated into the compositions of food freshness indicators. The obtained indicators were compared with an artificial indicator, bromothymol blue, and phenol red, concerning their volatile amine monitoring. Additionally, a model of volatile amine release based on the different ammonia solutions was applied in the research. The response of freshness indicators was estimated by the observation of color changes. Compared to the artificial indicators, the curcumin and pomegranate juices gave a similar response. Beetroot and carrot juices did not provide a desirable color change. Further research was made on the development of biopolymer containing freshness indicators based on bromothymol blue and phenol red. The indicators were evaluated for their response to the spoilage of fish and meat samples in the test tubes and in food packaging. Thus, two artificial indicators could be incorporated into effective food freshness indicators for smart packaging.

Effects of Clay Contamination on the Stability of Aqueous Foams at High Pressure

Summary Because of its low density, high viscosity, and good hole-cleaning performance, foam is used in the industry as a drilling and completion fluid. Due to these unique properties, foam can be applied in underbalanced drilling. After an extended period, however, the degradation of its thermodynamically unstable structure leads to the gradual loss of these valuable properties. While a number of research studies have been performed to investigate foam flow behavior, more is needed to know about their drainage characteristics and stability at high pressure. The primary goal of this investigation is to examine the effects of clay contaminants on the drainage of foam at high pressure. Moreover, the results and findings of this study not only show the effect of clay contaminants on foam stability but also help develop clay-based stable foam formulations without using chemicals that have the potential to contaminate groundwater or seawater. This paper shows the findings of an investigation on the aqueous foam stability in the presence of clay (bentonite and kaolinite) contaminants. Experiments were conducted at ambient temperature while varying foam quality and clay concentration at a constant pressure of 6.8 MPa. During the study, the foam was created in a flow loop. After generation, its rheology and stability were measured using a pipe viscometer and a vertical test tube (column). The hydrostatic pressure profile in the column was measured with time to assess foam drainage. The results show that clay type and concentration affect aqueous foam drainage and flow behavior. The impact of clay on these foam properties is controlled by foam quality. Adding more than 2.5% bentonite considerably enhanced foam stability and viscosity. In contrast, the impacts of kaolinite on these foam properties were minimal at the same concentration. The drainage became negligible when 5% bentonite was added to the foam. However, at a reduced concentration (2.5%), bentonite addition was only an effective stabilizer for low-quality foam (40%). Microscopic examination of the foams prepared under ambient conditions demonstrated the accumulation of colloidal particles at the plateau borders and nodes that block the drained liquid flow and reduce drainage.

Effects of common dissolved anions on the efficiency of Fe0-based remediation systems

Quiescent batch experiments were conducted to evaluate the influences of Cl−, F−, HCO3−, HPO42−, and SO42− on the reactivity of metallic iron (Fe0) for water remediation using the methylene blue (MB) method. Strong discoloration of MB indicates high availability of solid iron corrosion products (FeCPs). Tap water was used as an operational reference. Experiments were carried out in graduated test tubes (22 mL) for up to 45 d, using 0.1 g of Fe0 and 0.5 g of sand. Operational parameters investigated were (i) equilibration time (0–45 d), (ii) 4 different types of Fe0, (iii) anion concentration (10 values), and (iv) use of MB and Orange II (O-II). The degree of dye discoloration, the pH, and the iron concentration were monitored in each system. Relative to the reference system, HCO3− enhanced the extent of MB discoloration, while Cl−, F−, HPO42−, and SO42− inhibited it. A different behavior was observed for O-II discoloration: in particular, HCO3− inhibited O-II discoloration. The increased MB discoloration in the HCO3− system was justified by considering the availability of FeCPs as contaminant scavengers, pH increase, and contact time. The addition of any other anion initially delays the availability of FeCPs. Conflicting results in the literature can be attributed to the use of inappropriate experimental conditions. The results indicate that the application of Fe0–based systems for water remediation is a highly site-specific issue which has to include the anion chemistry of the water.

Bridging the gap between test tube and disease

A thermodynamics-based framework connects biophysical measurements of protein aggregation to neurodegenerative diseases and potential therapies.

Pool boiling heat transfer of ammonia outside enhanced tubes with various fin structures

Pool boiling heat transfer of ammonia on a smooth tube and three enhanced tubes was investigated at the saturation pressure ranging from 6.15 to 11.7 bar, which corresponds to the saturation temperature from 10 to 30 °C. The test tube with a length of 796 mm was immersed in the liquid pool of ammonia inside a cylindrical chamber having an internal diameter of 254.4 mm, and convection or pool boiling heat transfer outside the test tube was generated by flowing hot water through the tube. Three enhanced tubes of a low-finned tube (Low-fin), a low-finned tube with oblique cuttings (Turbo-C), and a finned tube having re-entrant cavities (Turbo-E) were prepared to examine the pool boiling enhancement on various finned tubes. Boiling hysteresis on the smooth tube was observed between when the heat flux increases and when the heat flux decreases, which resulted in the deviation of the heat transfer coefficients from the previous correlations when the heat flux decreases. A suitable correlation was suggested to compensate for the deviation of the heat transfer coefficients in case of decreasing the heat flux by modifying the Stephan-Abdelsalam correlation. Three enhanced tubes exhibited considerable enhancement in the heat transfer coefficients compared with the smooth tube, and boiling performance on the Turbo-E tube having re-entrant cavities was highly affected by the variation of the bubble diameter according to the saturation pressure. Enhancement factors of the enhanced tubes were obtained from the ratio of thermal conductance on the enhanced tube to that on the smooth tube.

Direct elemental analysis of plant oils by inductively coupled plasma mass spectrometry: Simple sample dilution combined with oxygen introduction into the plasma

Assessment of trace metal concentrations in plant oils has been considered a crucial quality control marker for potential health risks, oil flavour, and oxidative stability. A straightforward inductively coupled plasma mass spectrometry (ICP-MS) methodology was developed and validated through introduction of argon:oxygen gas mixture into plasma, allowing for a direct elemental analysis of organic matrices. This approach offers the advantage of a simple one-step preparation of plant oil samples with negligible contamination risks. The complete solubilization of the oil matrix enables the determination of total metal content from a single test tube with low dilution factor of 5. The modified plasma conditions resulted in the development of a robust and accurate ICP-MS method providing limits of detection at sub ng·g−1 levels. The ICP-MS method allowed the determination of trace levels of Ba, Cd, Cu, Fe, Mn, Pb, Sn, V, and Zn in olive, sunflower and rapeseed oils.

МИКРОБИОЦЕНОЗЫ ПРИ ОСТРОЙ КАТАРАЛЬНОЙ БРОНХОПНЕВМОНИИ ТЕЛЯТ

The purpose of the study is to conduct intravital diagnostics of calves with acute catarrhal bronchopneumonia using bronchoalveolar lavage samples and a detailed study of microbiocenoses from the collected contents. Objectives: development of a technique for intravital collection of bronchoalveolar lavage in calves with bronchopneumonia; study of the microbial landscape in calves with bronchopneumonia, characteristics of isolated microorganisms and their associations. The object of the study is calves aged 1–3 months, sick with acute catarrhal bronchopneumonia (n = 37). Pathological bronchoalveolar lavage was collected transnasally from the tracheal bifurcation area using sterile silicone catheters into sterile test tubes. Bacteriological studies were conducted using generally accepted methods at the Scientific and Educational Resource Center (SERC) Pharmacy of the People's Friendship University of Russia. As a result of the studies, 115 microorganisms of 13 species, classified into 9 genera, were isolated. The majority of isolates – 71 (61.7 %) were classified as gram-negative microorganisms. Staphylococcus aureus, Mannheimia haemolytica, Escherichia coli, Pasteurella multocida, Klebsiella pneumoniae, Streptococcus pyogenes and Klebsiella ozaenae were most often isolated from pathological material in cases of bronchopneumonia in calves. Isolates of E. coli were most often represented by O8, O26 and O111 serotypes. Of the 115 microorganisms that initiated bronchopneumonia in calves, the majority – 75 (65.2 %) cultures – had pathogenic properties. Retrospective analysis of microbial associations showed that most often the development of acute catarrhal bronchopneumonia in calves is caused by associations of opportunistic microorganisms, which included from 2 to 5 pathogens. Moreover, associations that included three members were most often isolated – 21 (56.8 %) and two members – 8 (21.6 %). Thus, in acute catarrhal bronchopneumonia of calves, microbiocenoses are formed in the inflammation focus, which can include various variations of opportunistic microorganisms.