Latvia University of Life Sciences and Technologies

Background and Aim: Maintaining intraocular pressure (IOP) stability during ophthalmic procedures is essential to ensuringsurgical success and reducing complications related to IOP fluctuations. This study aimed to evaluate IOP dynamics indogs undergoing mild-pain ophthalmic procedures under three different premedication protocols: butorphanol alone (B),butorphanol with medetomidine (BM), and butorphanol with acepromazine (BA).

The preservation and management of riparian zones in nature protection areas are challenging due to the simultaneous demands of nature protection regulations, active nature tourism burdens, and local community needs. The local community’s willingness to participate in riparian zone management is an essential contribution to establishing successful long-term riparian zone management. This study aimed to gain insight into the perceptions of the local community, particularly landowners, on the management perspectives of riparian zones in nature protection areas. We used a questionnaire survey to gather data from three distinct localities within the North Vidzeme Biosphere Reserve (NVBR). In total, 734 respondents were interviewed, of which 40% were landowners who owned land in riparian zones. Landowners did not differ significantly from those without property rights in their willingness to undertake voluntary work to improve the quality of riparian zones. Landowners more often use riparian zones for cultural and recreational activities. Overall, the landowners had similar perceptions of riparian zone management to respondents without property rights in the NVBR.

Edible films are a promising method for delivering probiotics in food. The survival of Lacticaseibacillus paracasei A11 and Lactobacillus helveticus MI-LH13 (7 log CFU/g), which were cultivated in liquid whey permeate (LWP), in films made from liquid acid whey protein concentrate (M) or liquid acid whey permeate (Z), was evaluated over 21 days at 25 °C and 4 °C. Film drying and matrix type had varying effects on strain survival. In the Z film, L. helveticus did not survive drying, but L. paracasei did. Both strains increased in the M film during drying. During storage, survival was low at 25 °C, but at 4 °C, strains survived better, especially in the M film (4.76–6.12 log CFU/g). The plain Z film was 28% more moist, 54% thinner, 70% more stretchable, 43% less opaque, 10% whiter, 47% redder, 43% bluer, and 64% less viscous compared to the plain M film. Incorporating both strains into M films (M + L. p, M + L. h) increased lightness, stretchability, and tensile strength while reducing viscosity and opacity (p < 0.05). The inclusion of the L. helveticus strain in M films reduced their thickness, whereas the presence of L. paracasei in the Z film enhanced solubility. Both films supported strain survival without negatively affecting the films’ rheological, optical, physicomechanical, and morphological properties, demonstrating the potential of LAB-incorporated edible films for probiotics delivery, shedding light on their adaptations and interactions within the film matrix. Furthermore, the impact of drying and storage conditions on LAB survival provides valuable insights for optimizing the formulation and application of these films in the food industry.

Precision beekeeping focuses on ICT approaches to collect data through various IoT solutions and systems, providing detailed information about individual bee colonies and apiaries at a local scale. Since the flight radius of honeybees is equal to several kilometers, it is essential to explore the specific conditions of the selected area. To address this, the aim of this study was to explore the potential of using crowdsourced data combined with geographic information system (GIS) solutions to support beekeepers’ decision-making on a larger scale. This study investigated possible methods for processing open geospatial data from the OpenStreetMap (OSM) database for the environmental analysis and assessment of the suitability of selected areas. The research included developing methods for obtaining, classifying, and analyzing OSM data. As a result, the structure of OSM data and data retrieval methods were studied. Subsequently, an experimental spatial data classifier was developed and applied to evaluate the suitability of territories for beekeeping. For demonstration purposes, an experimental prototype of a web-based GIS application was developed to showcase the results and illustrate the general concept of this solution. In conclusion, the main goals for further research development were identified, along with potential scenarios for applying this approach in real-world conditions.

Fruit seeds are often an underutilized side-stream of fruit processing. The most common approach to seed valorization is oil extraction due to the relative simplicity of the process. The partially or fully defatted seed meal is rarely further processed, even though seeds generally contain more protein and fiber than oil. The present study used single-screw extrusion (oil press), supercritical CO2 extraction, and a combination of the two, to defat Japanese quince (Chaenomeles japonica) seeds, and evaluated the defatted meals as sources of functional protein. Defatting with oil press and CO2 extraction proved similarly effective (reduced seed flour fat content from 11.75% to 6.40% and 5.32%, respectively); combining the two methods reduced fat content to 0.90%. The yield was minimally affected, but protein extract purity was defined by defatting efficiency (65.05% protein from non-defatted versus 82.29% protein from a combination-defatted meal). Defatting did not significantly affect amino acid composition but had a significant effect on every tested functional property (solubility, water, and oil binding capacity, apparent viscosity, foaming capacity, and emulsifying activity index). Of the tested defatting methods, supercritical CO2 extraction and the combination provided the best results from most aspects.

Modification and deterioration of old‐growth forests by industrial forestry have seriously threatened species diversity worldwide. The loss of natural habitats increases the concentration of circulating glucocorticoids and incurs chronic stress in animals, influencing the immune system, growth, survival, and lifespan of animals inhabiting such areas. In this study, we tested whether great tit (Parus major) nestlings grown in old‐growth unmanaged coniferous forests have longer telomeres than great tit nestlings developing in young managed coniferous forests. This study showed that the patches of young managed coniferous forests had lower larval biomass than old‐growth forests. Since insect larvae are the preferred food for great tit nestlings, the shortage of food may divert energy resources away from growth, which can show up as physiological stress, often raising the heterophil/lymphocyte (H/L) ratio. The H/L ratio revealed a significant difference in stress levels, being the highest in great tit nestlings developing in young‐managed pine forests. We also found that the development of great tit nestlings in young managed forests had significantly shorter telomeres than in old‐growth forests. Although nestling survival did not differ between the habitats, nestlings growing up in old‐growth forests had greater telomere lengths, which can positively affect their lifespan. Our results suggest that the forest habitats affected by industrial forestry may represent ecological traps, as the development of young birds in deteriorated environments can affect the age structure of populations.

Background/Objectives: Hormonal changes throughout a woman’s life cycle significantly affect serum lipid levels. Alterations in the serum lipid profile can increase the risk of cardiovascular diseases (CVDs). Additionally, nutrition and dietary habits are crucial for managing dyslipidemia. The current study evaluated the association between dietary habits and plasma lipid profiles among perimenopausal women in Latvia. Methods: The randomized clinical trial involved perimenopausal women (n = 61) aged 49 ± 3 years with moderately high low-density lipoprotein cholesterol (LDL-C) levels of 3.61 ± 0.30 mmol L⁻¹. A series of questionnaires were completed, including a questionnaire on the subject’s demographic, anthropometric, lifestyle, health, physical activity, and dietary factors, a 24 h food diary, a 72 h food diary, and a food-frequency questionnaire (FFQ). Blood testing was conducted for all participants, which included total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), alanine aminotransferase (ALAT), and glucose level analyses. Results: The consumption of refined sugar, honey, syrup, and jam demonstrated a strong positive association with higher levels of remnant cholesterol (β = 0.462, p ≤ 0.05) and non-high-density lipoprotein cholesterol (non-HDL-C) (β = 0.395, p ≤ 0.05). Similarly, the consumption of fruit juices is associated with increased LDL-C (β = 0.303, p ≤ 0.05) and non-HDL-C (β = 0.285, p ≤ 0.05). Conversely, higher meat and poultry consumption negatively correlates with TC levels (β = −0.290, p ≤ 0.05). Conclusions: This underscores the need for further examination to understand the impact of dietary habits on lipid profile.

In Northern Europe, the application of fungicides to winter wheat crops is primarily for the control of septoria tritici blotch (STB) caused by the fungal pathogen Zymoseptoria tritici. Unfortunately, intensive use of the demethylation inhibitors (DMI) and succinate dehydrogenase (SDHI) fungicides has led to the development of resistance in the European Z. tritici population. Levels of disease control achieved by both modes of action are partly dependent on the presence and frequencies of specific alleles, including CYP51-S524T, SDHC-T79N, C-N86S and C-H152R, in the population. To determine how frequent these are across the major wheat producing regions of Europe, a survey of Z. tritici was conducted in 2022, using specific qPCR assays to detect the frequencies of each allele. A west–east gradient of resistant allele frequencies was observed, with higher levels observed in the west. Comparing frequencies detected to a previous survey conducted in 2019 confirms the continued evolution of fungicide resistance in the European Z. tritici population. To ensure the continued effectiveness of these fungicides, it is essential ensure they are applied as part of an integrated disease control strategy that aims to reduce the overall need for their application.

The research was carried out to solve the problem of converting automotive diesel engines to alternative fuels with hydrogen admixtures. Methanol is considered as an alternative fuel which is a cheaper alternative to commercial petroleum diesel fuel. The chemical essence of improving the calorific value of alternative methanol fuel was investigated. Calculations showed the energy effect of burning an alternative mixture with hydrogen additives exceeds the effect of burning the same amount of methanol fuel. The combustion energy and engine power increase is achieved due to the efficient use of the engine exhaust gases heat and chemical conversion of methanol. An experimental installation was created to study the work of a converted diesel engine on hydrogen mixtures, and thermochemical regeneration processes. Experimental studies of the energy and environmental parameters of a serial diesel engine converted to work on an alternative fuel with hydrogen admixtures were conducted. Experimental studies have shown converting diesel engines to work on alternative fuels with hydrogen admixtures is structurally possible and technically advantageous whereas emissions of toxic components decrease and engine power increases. Conversion of diesel engines to alternative fuels with hydrogen admixtures is very profitable since the price of methanol is on average 30–35% of the cost of petroleum fuel.

Organic fermented milk products are an area of interest combining functional properties and sustainable practices. Limited information is available regarding the specific components of organic milk that may impact the growth of lactic acid bacteria. This study emphasised the differences in bioactive compounds between organic and conventional milk and their potential influence on lactic acid bacteria growth. Analysis of organic (n = 15) and conventional (n = 15) farm milk using GC-MS revealed differences in fatty acid (FA) concentrations, mainly mono-, polyunsaturated fatty acids, and conjugated linoleic acid. Individual FA, such as stearic, linoleic, and oleic acids, were up to 33.6%, 31.0%, and 25.23% higher in conventional milk. Detection of the whey proteins using the enzyme-linked immunosorbent assay (ELISA) showed lysozyme content was up to 40.6% higher in conventional (22.04 µg L ⁻¹ ) than in organic (15.68 µg L ⁻¹ ) milk. Conversely, lactoferrin content was 20.4% higher in the organic (45.27 µg L ⁻¹ ) than in conventional (36.04 µg L ⁻¹ ). No difference in the content of immunoglobulin A was found. The higher concentrations of lysozyme, mono- and polyunsaturated fatty acids in conventional milk could enhance a higher inhibitory activity against lactic acid bacteria compared to organic milk.

The objective of the current study was to create a frozen dessert with reduced fat and sugar content, using plant-based ingredients and to evaluate its physical, rheological and nutritional properties. The dessert formulations were developed using plant-based ingredients such as sweet potatoes, potatoes, carrots, and beetroot, combined with date sugar, corn starch and skimmed milk powder. Chemical analysis showed that the sweet potato (SP) sample had the highest energy value due to its carbohydrate and fat content, while the carrot (CR) sample had the lowest. Rheology tests revealed that beetroot-based (BR) samples exhibited the highest viscosity, likely due to the high dietary fibre content in beetroots, while the CR sample was the most fluid, attributed to its lower solids content. The study showed that air bubble size influenced texture and melt behaviour. The overrun, a measure of air incorporation, was highest in the BR sample, contributing to a lighter texture. The hardness of the desserts was influenced by solid content and ingredient composition, with the CR sample being the hardest. Melting rate analysis revealed that all samples melted slowly, with the SP, SPP (sweet potato + potato), and BR samples melting uniformly over time. Overall, the study demonstrated that plant-based ingredients could effectively replace traditional high-fat animal-based ingredients, yielding frozen desserts with favourable nutritional profiles, acceptable rheological properties, and desirable physical characteristics.

The European Union’s Green Deal agenda emphasises the major importance of cleaner and more environmentally friendly energy sources for further economic development. Hydrogen is one of the potential renewable fuels that can replace fossil fuels in a variety of economic applications. The green hydrogen production across Europe is a key factor in achieving this goal. The aim of the study is to determine the influence of the connection between the availability of renewable energy sources, innovation, and economic development patterns on hydrogen production advancement. The research provides a comprehensive correlation analysis between the number of green hydrogen production sites and their capacity with statistical indicators describing economic growth, population, innovation, and particular economic characteristics within a particular EU Member State. The statistical data of this research outline the period from 2021 until the beginning of 2024. The results of the study suggest that nine of the 23 indicators examined – population size, gross domestic product, investment in research and development, total manufacturing value, overall industry value, total electricity produced, renewables in electricity production, solar power, and wind power in electricity production – have a strong or very strong positive correlation with hydrogen production. Furthermore, the analyses revealed that countries with large populations and high GDP volumes are more likely to develop hydrogen production in existing market circumstances.

The increasing reliance on renewable energy sources such as solar and wind power necessitates the development of advanced forecasting techniques to address the inherent variability and unpredictability of these energy systems. Accurate forecasting is vital for optimising energy production, maintaining grid stability, and effectively integrating renewable energy into power systems. Traditional forecasting methods often struggle to adapt to rapidly changing environmental conditions and new data inputs, limiting their effectiveness in dynamic contexts. This study introduces the Self-Improvement Cycle (SIC) module, which is designed to enhance forecasting accuracy through continuous learning, adaptation, and feedback integration. The SIC module leverages advanced machine learning algorithms, reinforcement learning techniques, and reflective practice principles to create a self-improving framework that dynamically updates models based on real-time data and external feedback. The module’s design incorporates multiple feedback loops, enabling the system to iteratively refine its performance and remain robust in the face of changing conditions. Reflective practice, a concept drawn from psychology, plays a critical role in the SIC module by facilitating ongoing evaluation and adaptation. By learning from previous predictions and continuously adjusting algorithms, the SIC module demonstrates its potential to improve forecasting accuracy across various domains, with a particular emphasis on renewable energy forecasting. The theoretical and mathematical foundations of the SIC module are explored, showcasing its capability to enhance predictive accuracy and resilience in an evolving energy landscape.

The paper presents a general view of the new working surface of the harrow with helical working tools. With the help of SOLID WORKS software package, a computer model of this soil tillage tool with helical working tools for surface tillage has been created. The obtained new analytical dependence made it possible to determine the traction resistance of the harrow, equipped with a spiral working element which, in turn, served as the basis for constructing graphs, showing a change in the traction resistance depending on various values angle of attack of the harrow and the soil resistance.On the basis of a computer model of a helical tillage tool created in the SOLID WORKS program, it was found that when the angle of attack of the tool increases, the drag resistance P increases, as well, and its greatest increase is observed for the maximum diameter of the tool D. It was found that the thickness of the helix λ has a much smaller effect on the traction resistance compared to the parameter D.

The article presents the results of theoretical and experimental laboratory investigations of an improved screw conveyor for bulk agricultural materials that has been created, which, instead of a solid spiral winding, fixed to the drive shaft, uses a spiral winding, formed by separate curvilinear planes (blades), which are also separately fixed to the shaft, yet as a whole form a single spiral. An analytical dependence was obtained for determination of the magnitude of the torque on the drive shaft of this transport working element. The numerical values, obtained as a result of the laboratory experiments, made it possible, when conducting a regression analysis, to derive a new analytical expression in the form of a regression equation. The analysis of the regression equation shows that these factors, which have a significant impact upon the increase in the torque, are the factors: x1 (D) – the diameter of the fixed casing in which the screw is installed and x2 (ψ) – the filling factor of the conveyor with the transported bulk material. Increasing the value of the factor x3(n), i.e., the rotation speed of the vane working body leads to a decrease in the torque value.

This study examines the shared electric scooter usage patterns in Riga across 2021 and 2022 and assesses the potential for reducing greenhouse gas emissions in the city’s urban transport system. Analysing 3.9 million scooter trips over the two-year period, the research highlights a tripling in the use of shared scooters and a shift towards shorter rides, resulting in an average use of only 7 km per day per scooter. This trend has resulted in CO 2 emissions to 54.16 g CO 2 per passenger kilometre, raising the total emissions from shared scooters in 2022 to 163.3 tonnes, and in fact increasing the net transportation CO 2 emissions in Riga by 49.2 tonnes, by largely replacing zero-emission modes of transport like walking. In response to these challenges, the research explores the implementation of photovoltaic (PV) energy-powered charging docks as a method to maintain scooter operations. While energy consumption is not the largest contributor to the scooters’ CO 2 emissions, by also eliminating the need for scooter transportation for charging the adoption of on-site generated PV energy could yield a substantial CO 2 emission reduction of up to 34 %. This approach could hypothetically result in a 71-tonne reduction in CO 2 emissions from electric scooters, thus potentially establishing scooters as a net positive influence to Riga’s transport emissions, producing a net 11 tonne CO 2 emisssion reduction.

Incorporating extruded pea hulls (EPH) into wheat bread increases its nutritional value by increasing dietary fiber content, which in turn influences the physicochemical properties and sensory attributes of bread. This study aimed to assess the effect of varying EPH levels on the rheological properties of wheat dough, as well as on the physical and sensory attributes of wheat bread, providing insight into the optimal EPH inclusion level. Farinograph analysis indicated that the inclusion of extruded pea hulls progressively increased the water absorption capacity. At higher EPH replacement levels, bread exhibited decreased specific volume, increased hardness, reduced porosity, darker color, and pronounced sensory attributes of pea aroma and pea taste. Bread with 5–15% EPH retained physical qualities comparable to bread without EPH, with 5% EPH replacement particularly improving specific volume, porosity, and texture. However, 20–30% EPH significantly impaired bread quality, resulting in denser crumb, darker crumb color, and intensified pea aroma. These findings suggest that moderate EPH inclusion (up to 15%) is optimal for enhancing fiber content without compromising bread quality, while higher levels (20% and more) may negatively affect both physical and sensory attributes.

The growing emphasis on food safety and healthier lifestyles, driven by industrial expansion and scientific priorities, has highlighted the necessity of managing harmful microorganisms to guarantee food quality. A significant challenge in this domain is the control of pathogens that are capable of forming biofilms, entering a sessile state that enhances their resistance to broad-spectrum antibiotics. Essential oils, renowned for their antibacterial properties, present a promising natural alternative for food preservation. In this study, we analyzed the chemical composition of Santalum album essential oil (SAEO) using GC-MS, identifying (Z)-α-santalol (57.1%) as the primary constituent. Antimicrobial activity was confirmed through disc diffusion and minimum inhibitory concentration (MIC) assays against Gram-positive and Gram-negative bacteria and yeast from the genus Candida. Additionally, in situ experiments demonstrated that vapor-phase SAEO effectively inhibited Serratia marcescens on the food model, supporting its potential as a natural preservative. MBIC assays, crystal violet staining, and MALDI-TOF MS analysis on S. enterica biofilms were used to further evaluate the antibiofilm effects of SAEO. The crystal violet assay revealed a strong antibiofilm effect, while the MALDI-TOF MS analysis showed changes in the bacterial protein profiles on both glass and plastic surfaces. SAEO also showed significant anti-Salmonella activity on vacuum-packed carrot slices. SAEO outperformed the control samples. The insecticidal activity against Megabruchidius dorsalis was also studied in this work, and the best insecticidal activity was found at the highest concentrations. These findings indicate that SAEO could serve as a valuable component in food preservation, with notable antibacterial and antibiofilm benefits.

Tan spot caused by Pyrenophora tritici-repentis is a severe threat to wheat production in all major wheat-growing regions. Sustainable tan spot control can be achieved by an integrated approach, including responsible management of fungicide sprays. The data about the sensitivity of P. tritici-repentis to various fungicides in the Baltic Sea region are rare. In this study, we described the variation of P. tritici-repentis sensitivity to four fungicide active ingredients to detect the formation of resistance to the most commonly used quinone-outside inhibitor (QoI) and 14α-demethylase inhibitor (DMI) fungicides in the pathogen’s population in Latvia. The effect of prothioconazole, mefentrifluconazole, pyraclostrobin, and azoxystrobin on 93 P. tritici-repentis strains from various hosts was tested in vitro by assessing mycelium linear growth inhibition at three different active ingredient concentrations (0 0.01, 0.1 and 0.5 mg L−1). Pathogen sensitivity significantly (p < 0.001) varied between the fungicide active ingredients and strains. The prothioconazole (concentration 0.5 mg L−1) had the most significant effect, with a median mycelial growth inhibition of 70.34%, followed by pyraclostrobin (47.02%), azoxystrobin (24.24%), and mefentrifluconazole (11.11%). Mutation G143A was detected in cytb gene sequences and confirmed the resistance formation in Latvia’s P. tritici-repentis population, while F129L and G137R mutations were absent. This study provided insight into P. tritici-repentis population’s sensitivity to active ingredients of DMI and OoI fungicide groups, helping to fill the knowledge gap about the pathogen fungicide sensitivity in this region.