Optimal Temperature Conditions Research Articles

Removal of arsenic and recovery of tin from arsenic-containing multi-metallic materials by vacuum reduction roasting

Arsenic-containing multi-metallic materials, are typical hazardous wastes generated in the process of tin recovery from zinc smelting leach slag, exhibit low resource utilization and pose a significant risk of environmental pollution. This research proposed a vacuum reduction roasting technique utilizing anthracite as the reducing agent to remove arsenic and reclaim tin from such materials, characterized by high arsenic levels (8∼wt%) and the presence of several valuable metals. The results indicated that the arsenate in these materials was transformed into As2O3, which has better volatility, while SnO2 was converted to SnO and Sn. Moreover, under the optimal conditions of a roasting temperature of 750 °C, 10 % anthracite, and a roasting duration of 3 h, the arsenic removal efficiency reached 96.97 %, and the tin recovery rate was 84.48 %. Consequently, the arsenic concentration decreased to 0.53 %, and the tin concentration in the roasted product increased from 17.70 % to 31.41 %. The final product contained phases of arsenic and tin, including Sn, SnO2, and FeAs. Meanwhile, this study provides a promising solution for the green and efficient separation of tin and arsenic in typical arsenic-containing multi-metallic materials.

Preliminary Studies on the Invertebrate Microfauna Associated with A Terrestrial Moss, Hyophila sp. in Urban Areas of Chennai, Tamil Nadu, India

Bryophytes provide microhabitat, optimal temperature condition, and act as reliable nutrient sources for invertebrate fauna. In the present study, microscopic analysis of the invertebrate micro fauna associated with a terrestrial moss, Hyophila sp. was examined. The work was conducted for a period of six months from october to march and the invertebrate microfauna was recorded for two different seasons (october-december and january – march). It was found that protozoans, rotifers, nematodes, eggs or cysts and certain larvae were present throughout the study period. However, their proportions were significantly altered during the two different seasons. Metabolically active animals were seen in higher numbers during monsoon period (October-december) compared to higher number of eggs and cysts during drier months (January –march). This study highlights the different microfaunal population associated with the urban moss, Hyophila sp. and adds to the growing pool of literature on moss- microfaunal association.

Effects of Liquidambar Orientalis Oil on Liver and Kidneys in Heathy Wistar Rats

Background: Nowadays, the tendency towards alternative herbal therapies has increased due to the side effects of drugs. However, since the contents, method of use, dosage and toxic effects of herbal products are not fully known, undesirable situations are occasionally encountered. However, there are many experimental studies on the cytotoxicity of L. orientalis oil, most of these studies are in vivo modelling. In this study, the cytotoxic effects of L. orientalis oil on the liver and kidneys were investigated in healthy rats by oral administered. Methods: The study material consisted of 18 female Wistar albino rats (190-280 g) aged 8-10 weeks. All animals were housed under optimal temperature, light and humidity conditions and fed with normal rat pellet food ad libitum. Housing conditions were checked daily. Three groups were organized as L. orientalis oil, olive oil and control group, respectively. Each group consisted of 6 rats. L. orientalis oil group: L. orientalis oil (150 mg/kg) dissolved olive oil (0.6 mL). Olive oil group: Olive oil (0.6 mL). Control group: Empty gavage. The entire trial was performed by intragastric gavage once a day for 14 days. Result: The obtained data showed that serum biochemical parameters remained within normal ranges in oral use of Liquidambar orientalis oil (150 mg/kg) and did not show any difference with the control and olive oil groups. No pathological changes related to cytotoxicity were found in the samples taken from liver and kidney tissues.

The impact of polystyrene nanoplastics (PSNPs) on physiological and biochemical parameters of the microalgae Spirulina platensis

Nanoplastics, as emerging pollutants, have harmful effects on living organisms and the environment, the mechanisms and extent of which remain unclear. Microalgae, as one of the most important biological groups in the food chain and sensitive environmental indicators to various pollutants, are considered a suitable option for investigating the effects of nanoplastics. In this study, the effects of polystyrene nanoplastics on the growth rate, dry weight, chlorophyll a and carotenoid levels, proline, and lipid peroxidation in the Spirulina platensis were examined. Three concentrations of 0.1, 1, and 10 mg L-1 of PSNPs were used alongside a control sample with zero concentration, with four repetitions in one-liter containers for 20 days under optimal temperature and light conditions. Various analyses, including growth rate, dry weight, proline, chlorophyll a and carotenoid levels, and lipid peroxidation, were performed. The results indicated that exposure to PSNP stress led to a significant decrease in growth rate, dry weight, and chlorophyll a and carotenoid levels compared to the control sample. Furthermore, this stress increased the levels of proline and lipid peroxidation in Spirulina platensis. Morphological analysis via microscopy supported these findings, indicating considerable environmental risks associated with PSNPs.

Modelling and optimization of electrodeposited amorphous Fe-P alloys using central composite design and response surface method

Central composite circumscribed (CCC) design and response surface methodology (RSM) were used to model and optimize the electrodeposition of amorphous Fe-P alloys. Based on our previous single-factor experimental results, the significance of influencing factors was ranked using analysis of variance (ANOVA) method. Three factors, significantly impacting the P content in deposits, hardness and corrosion current density, were identified, including bath temperature, pH values and H2PO2− concentration. The statistic relationships between process parameters and individual responses were established based on the CCC experimental data and RSM. The optimal parameters for each response were derived and the influences of interaction terms were investigated. The predicted maximum P content of 26.35 wt% was achieved at a bath temperature of 60℃, a pH of 1.2 and H2PO2− concentration of 60 g/L. The predicted highest microhardness was 534 HV0.1 under the optimal conditions of temperature of 60 ℃, pH value of 1.6 and H2PO2− concentration of 49 g/L. The lowest corrosion current density was predicted to be 1.34 μA·cm−2 under the conditions of a bath temperature of 60℃，a pH value of 1.2, and a H2PO2− concentration of 53 g/L. A desirability function was applied to explore the optimal comprehensive performance of both high hardness and low corrosion current density. The optimal parameter combination for comprehensive performance was bath temperature of 60℃, pH of 1.4, and H2PO2− concentration of 49 g/L, and the resulting hardness and corrosion current density were 527 HV0.1 and 2.40 μA·cm−2, respectively. Due to the complex electrodeposition mechanism of amorphous Fe-P alloys, the predicted P content in deposits largely deviated from the experimental result, but the hardness, corrosion current density and comprehensive performances show high prediction accuracy.

Exergoeconomic evaluation and multi-objective optimization of a novel geothermal-driven zero-emission system for cooling, electricity, and hydrogen production: capable of working with low-temperature resources

Geothermal energy is an abundant natural resource in many regions around the world. However, in some areas, the temperature of the geothermal energy resource is too low to be efficiently harvested. Organic Rankine cycles (ORCs) are known for recovering heat from low-temperature resources and generating electricity. Furthermore, half-effect absorption chillers (HEACs) are designed to produce cooling with low-temperature resources. This study proposes a novel configuration that utilizes an ORC for electricity generation, a HEAC for cooling production, and a PEM electrolysis system to produce hydrogen. The power section consists of two turbines, one driven by the vapor produced from the geothermal flow expansion, which powers the PEM section, while the other turbine in the ORC is used to drive pumps and electricity production. First, the system is thermoeconomically analyzed for an initial set of inputs. Then, various parameters are analyzed to determine their influences on system performance. The analyses reveal that the system can work with geothermal source temperatures as low as 80 °C, but the exergy and energy (thermal) efficiencies decrease to around 17% under the base settings. Furthermore, the system is capable of working with resource temperatures up to 170 °C. Ten parameters are found to affect the system’s efficiency and effectiveness. To optimize the system, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is implemented to find the optimum conditions. The objective functions are exergy efficiency and unit polygeneration cost (UPGC), which can conflict. The optimization shows that the exergy efficiency of the system can reach 48% in the optimal conditions (for a heat source temperature of 112 °C and a mass flow rate of geothermal fluid of 44 kg/s), with a hydrogen production rate of 1.1 kg/h.

Innovative Plant-Derived Biomaterials for Sustainable and Effective Removal of Cationic and Anionic Dyes: Kinetic and Thermodynamic Study

The aim of this study is to purify industrial textile effluents by treating two types of commonly encountered dyes: blue maxilon (BM), of cationic nature, and black eriochrome (NE), of anionic nature. We intend to employ an innovative approach based on the adsorption of these dyes onto a novel vegetal biomaterial derived from Aleppo pine fibers (FPAs). A kinetic and thermodynamic study was conducted. The effect of some physicochemical parameters on both dye adsorption and FPAs was also evaluated. The modeling of the adsorption results was performed using Langmuir, Freundlich, Temkin, and Dubinin Radushkevich (D-R) isotherms. The results indicate that the equilibrium time strongly depends on the initial concentration of the two dyes, being 60 min with pseudo-second-order adsorption kinetics for both dyes. Adsorption isotherms under the optimal conditions of adsorbent mass, temperature, medium pH, and dye concentration were used to determine the maximum adsorption efficiency, which was close to 93% and 98% for BM and NE, respectively. The results also show that the adsorption of both dyes on FPAs fits well with Langmuir’s model. The thermodynamic study indicates that the adsorption of both dyes on FPAs is spontaneous and exothermic in nature for BM and endothermic for NE.

A nanoDiamond/gold nanoparticle-based electrochemical immunosensor for the detection of HER 2 cancer biomarker

We report a highly sensitive electrochemical immunosensor based on a nanohybrid platform for the detection of the breast cancer biomarker human epidermal growth factor receptor 2 (HER 2). NanoDiamond (nanoD) and gold nanoparticles (AuNPs) immobilised by drop coating and electrodeposition methods, respectively, were employed to fabricate an immunosensor for HER 2 detections on a glassy carbon electrode (GCE). Voltammetry and electrochemical impedance spectroscopy (EIS) techniques were used to characterise each step of the modification process of the immunosensor. In addition, transmission electron microscopy (TEM), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) techniques were used to characterise the materials used to fabricate the modified electrode. Under optimal conditions of temperature, time, and pH (35 °C, 50 min, and pH 7.2), different concentrations were investigated within a wide range of 1 pg mL−1 to 50 ng mL−1 using differential pulse voltammetry (DPV). With a low detection limit of 0.29 pg mL−1 from the DPV analysis, the immunosensor showed very good sensitivity and had a high specificity for HER 2. Additionally, the immunosensor demonstrated good applicability in the analysis of HER 2 in human serum samples, demonstrating a potential for use in the early identification of breast cancer.

VIBRATORY DRYERS AS AN EFFECTIVE TOOL FOR REDUCING ENERGY CONSUMPTION IN PRODUCTION

Drying of materials is a complex technological process used in various industries and often is one of the main stages of production. This process, in particular for bulk materials, depends on humidity, particle size, hydrodynamic conditions of the particles flowing through the drying agent and environmental parameters. Grain dryers expose grain to more stringent conditions than natural drying, which can potentially lead to a deterioration in grain quality. The combination of these factors determines the nature of the entire process. In agricultural production, the drying stage is one of the most important for grain preservation. Currently, the convective drying method is widely used for this process. However, along with its advantages, this method also has a number of significant disadvantages, one of the most significant of which is its high energy consumption. In this regard, scientific research is being intensively conducted to develop ways and methods to reduce the energy intensity of the convective drying method. The effects of vibration on raw materials are being rapidly introduced in various industries. The use of vibration technologies during drying intensifies the process of processing grain raw materials due to the rapid renewal of its surface in contact with the drying agent. Fast and efficient drying with vibration technology reduces moisture content and the risk of the appearance of bacteria and mold in the grain. The construction of the dryer using vibration technology helps to avoid overheating of the grain, providing optimal temperature conditions, which contributes to the preservation of nutrients and other useful properties of bulk agricultural materials.

The Physicochemical Basis for the Production of Rapeseed Oil Fatty Acid Esters in a Plug Flow Reactor

This article describes the results of a comprehensive comparative study of the production of fatty acid ethyl esters (FAEEs) for use as biodiesel in perfect mixing reactors (PMRs) and plug flow reactors (PFRs). The products obtained on a laboratory scale at all stages of the separation and purification of the FAEE phase were analyzed using the FTIR, XRF and GC-MS methods. We compared distillation methods for the separation of stoichiometrically excessive ethanol from the reaction mixture. Neutralization methods with H2SO4 solution and carbonation with CO2 were applied for FAEE phase purification from the catalyst. Emulsions formed during the water flushing stage were analyzed via the optical microscopy method. The optimal conditions of stirring speed and temperature were selected to maintain a high level of FAEE–water phase contact area with minimum phase separation time. The efficiency of the carbonation method for catalyst neutralization in the FAEE phase has been proven, allowing us to consider this method as an alternative to the traditional acid neutralization method. According to the results of experimental studies, we have developed a new high-performance technological scheme for the production of fatty acid esters in PFRs. The synthesis of FAEEs in a stoichiometric excess of ethanol of about 1:50 allowed us to increase the reaction rate and productivity of the synthesis unit after the transition from a PMR to a PFR. The yield of the product amounted to 86.7%. The purified FAEE fraction complied with most EN14214 specifications.

Determination of Optimum Conditions of pH and Temperature on the Saccharification of Cassava Starch by Amyloglucosidase

Saccharification is the process of breaking complex carbohydrate into its monosaccharide components. The present study however was carried out to determine the optimum conditions of pH and temperature on the saccharification of cassava starch by amyloglucosidase. The optimum conditions of cassava starch hydrolysis was determined by using a pure culture of a thermostable amyloglucosidase for saccharification, and the activities of the enzyme determined at varying pH, temperature and time. Results showed that sample dry weight significantly decreased with respect to increased value of pH, temperature and time, while reducing sugar and dextrose equivalent significantly increased with respect to increased time. The optimal reducing sugar and dextrose equivalent were 74.23% and 96.41 DE, respectively at pH 4.5, 55 °C and 72 h. The glucose obtained from this process may serve as a substrate in fructose syrup production.

First Report of Brown Leaf Rot Disease on Dendrobium nobile Caused by Xylaria flabelliformis in Guizhou Province, China.

Dendrobium nobile is the largest species of the Orchidaceae family and produces dendrobine, a compound with medicinal properties (Sarsaiya et al., 2020a; Sarsaiya et al., 2024; Qian et al., 2024). The accumulation of dendrobine in D. nobile is regulated by various pathogenic fungi, which directly and indirectly influence dendrobine biosynthesis (Sarsaiya et al., 2019a; Sarsaiya et al., 2019b). In a field planted with D. nobile in Guizhou Province, China, small lesions were initially observed on the upper part of the leaves from May to June 2019, which later developed into larger brown necrotic leaf lesions. Over time, these lesions greatly impacted the medicinal value (dendrobine) and productivity of the plant. A pure culture of Xylaria flabelliformis from infected wild D. nobile leaves was recovered and subsequently cultured on potato dextrose agar (PDA) at 25 °C for 5 days. Xylaria flabelliformis grew slowly and was composed of white mycelia. Colonies were initially white, with a regular margin, and formed stromata that consisted of mycelia sterilia without ascospores. We identified the strain as Xylaria flabelliformis based on its morphological characteristics (Liu et al., 2007) and by sequencing elongation factor-1α (EF-1α). The length of the DNA sequence of EF-1α that was used for the analysis of Xylaria flabelliformis was 1188 bp. BLASTx (nucleotide 6-frame translation-protein) analysis using the National Center for Biotechnology Information database showed that the obtained protein sequence (BLASTx protein accession no.: UTS95822.1, BLASTn nucleotide sequence accession no.: MW508334.1) had the highest similarity (98.21%) with the X. flabelliformis hypothetical protein (TRX95197.1) based on a thorough phylogenetic comparison with other Xylaria species. Healthy D. nobile seedlings were planted in pots and sterilized. The terminal leaves were excised from all pre-sterilised D. nobile seedlings and inoculated with Xylaria flabelliformis mycelial plugs, whereas sterile PDA plugs and moist cotton plugs were used as controls. All seedlings were maintained under optimum temperature and humidity conditions (25 °C and 80%, respectively) for seven days for observation and analysis. All experiments were performed in triplicate. After the incubation period, brown leaf rot lesions were observed for the first time on the inoculated D. nobile leaves, but no symptoms were observed on the leaves of the two control groups (sterile PDA plugs and moist cotton plugs). To complete Koch's postulates, Xylaria flabelliformis was re-isolated and identified from all diseased tissues by DNA sequencing of the EF-1α. It was determined for the first time that Xylaria flabelliformis can cause brown leaf lesions in D. nobile. Moreover, the pathogenicity of Xylaria flabelliformis in D. nobile has not been previously reported (Mead et al., 2019; Meng et al., 2019; Sarsaiya et al., 2019a; Sarsaiya et al., 2020b; Chen et al., 2023; Rinchen, 2023; Cao et al., 2024). To the best of our knowledge, this is the first report of BLRS lesions in D. nobile leaves caused by Xylaria flabelliformis in Guizhou Province, China. Identification of Xylaria flabelliformis as a pathogen of D. nobile is crucial for advancing effective management and control practices against brown leaf rot disease. This discovery provides valuable insights into the development of targeted strategies to mitigate the impact of Xylaria flabelliformis on D. nobile, safeguard medicinal properties such as dendrobine, and enhance overall productivity.

‘Not everything that can be counted counts’ in ethanol toxicological results: an antemortem and postmortem technical interpretation focusing on driving under the influence

Abstract Ethanol blood analysis is the most common request in forensic toxicology, and some studies point to positive results in approximately one-third of all unnatural deaths. However, distinguishing sober deaths from drunk deaths is not as simple as it may seem. This technical, clinical, and forensic interpretation is proposed to interpret the ethanol toxicological results, discussing several artifacts and pitfalls that must be considered, namely focusing on driving under the influence. This work is presented with a practical and objective approach, aiming to alleviate the complexities associated with clinical, physiological, pathophysiological, and toxicological aspects to enhance comprehension, practicality, and applicability of its content, especially to courts. Particularly the physical integrity of the body, the postmortem interval, putrefactive signs, anatomic place of blood collection, alternative samples such as vitreous humor and urine, the possibility of postmortem redistribution, the inclusion of preservatives in containers, and optimal temperature conditions of shipment are among some of the aspects to pay attention. Although the proposal of several biomarkers of postmortem microbial ethanol production, their translation to forensic routine delays is limited due to current uncertainties and analytical constraints that render their application. Specifically, in the interpretation of ethanol toxicological results, ‘not everything that can be counted counts and not everything that counts can be counted’ (attributed to Albert Einstein).

Simultaneous removal of perfluorooctanoic acid and thiocyanate by modified activated carbon fiber/persulfate system

In this study, NaOH-modified activated carbon fiber (NaOH-ACF) was used as a catalyst to activate persulfate (PS) for the removal of perfluorooctanoic acid (PFOA) and thiocyanate (SCN−) from wastewater. The effects of the crucial parameters in the NaOH-ACF/PS process, including NaOH-ACF dosage, PS concentration and initial pH, were investigated and optimized using response surface methodology. The experimental results indicated showed that under the optimal reaction conditions of NaOH-ACF dosage (0.40 g/L), PS concentration (2.0 mmol/L), pH (3.0), and temperature (25 °C), the removal efficiencies for PFOA and SCN− reached 93.63 % and 95.17 %, respectively, within 60 min of reaction. When PFOA and SCN− coexisted in the reaction system, it was observed that PFOA had minimal effect on the removal of SCN−, while SCN− actually enhanced the removal of PFOA. Free radical identification experiments demonstrated that the NaOH-ACF/PS system generated free radicals (O2−, SO4−, OH) and non-free radicals (1O2), which cooperatively facilitated the degradation of PFOA and SCN−. Furthermore, Liquid Chromatograph-Mass Spectrometer (LC-MS) analysis results have been used to speculate on the possible degradation pathways and intermediates of PFOA. The material characterization results indicated that NaOH-ACF possesses abundant surface functional groups with excellent adsorption and catalytic properties. Thus, the NaOH-ACF-activated PS advanced oxidation process offered a promising approach for the simultaneous removal of Perfluorinated compounds and thiocyanates.

Adsorption of Cadmium (II) Ions Using Cassava Peel Activated Carbon: Study of Adsorption Kinetics, Isotherms and Thermodynamics

Heavy metals Cd2+ is a dangerous pollutant of water and ecological systems if it is above the quality standard threshold. Cassava peel has a fairly high carbon element content, namely 59,31%, so it can be used as an activated carbon to break down Cd2+ metals ions in water. This research aims to determine kinetic modeling and adsorption isotherms of Cd2+ ions using CPAC activated by H3PO4, determine the optimum pH and temperature conditions for Cd2+ ion adsorption and determine the adsorption capacity of Cd2+ ions using CPAC activated by H3PO4. CPAC is made through a carbonization process at a temperature of 500 °C for 1 hour. Next, it was impregnated with H3PO4 at a concentration of 30 % with a ratio of 1:5 (w/w) for 24 hours and physically activated at a temperature of 600 °C for 1 hour. Based on research, kinetic modeling and adsorption isotherms of Cd2+ ions using CPAC activated by H3PO4 following Pseudo-Second-Order (PSO) kinetic modeling and Freundlich isotherm, the optimum pH and temperature conditions for Cd2+ ion adsorption were obtained at pH 5 and temperature 25 °C. Thermodynamic parameters such as Gibbs energy (∆G°), enthalpy (∆H°), and entropy (∆S°), have been evaluated and indicate physical, spontaneou, and exothermic adsorption processes. The adsorption capacity of Cd2+ ions using CPAC activated by H3PO4 is 5.2219 mg/g.

Integrated analysis of transcriptome and small RNAome reveals regulatory network of rapid and long-term response to heat stress in Rhododendron moulmainense

Main conclusionThe post-transcriptional gene regulatory pathway and small RNA pathway play important roles in regulating the rapid and long-term response of Rhododendron moulmainense to high-temperature stress.The Rhododendron plays an important role in maintaining ecological balance. However, it is difficult to domesticate for use in urban ecosystems due to their strict optimum growth temperature condition, and its evolution and adaptation are little known. Here, we combined transcriptome and small RNAome to reveal the rapid response and long-term adaptability regulation strategies in Rhododendron moulmainense under high-temperature stress. The post-transcriptional gene regulatory pathway plays important roles in stress response, in which the protein folding pathway is rapidly induced at 4 h after heat stress, and alternative splicing plays an important role in regulating gene expression at 7 days after heat stress. The chloroplasts oxidative damage is the main factor inhibiting photosynthesis efficiency. Through WGCNA analysis, we identified gene association patterns and potential key regulatory genes responsible for maintaining the ROS steady-state under heat stress. Finally, we found that the sRNA synthesis pathway is induced under heat stress. Combined with small RNAome, we found that more miRNAs are significantly changed under long-term heat stress. Furthermore, MYBs might play a central role in target gene interaction network of differentially expressed miRNAs in R. moulmainense under heat stress. MYBs are closely related to ABA, consistently, ABA synthesis and signaling pathways are significantly inhibited, and the change in stomatal aperture is not obvious under heat stress. Taken together, we gained valuable insights into the transplantation and long-term conservation domestication of Rhododendron, and provide genetic resources for genetic modification and molecular breeding to improve heat resistance in Rhododendron.

Температурные изменения в мясных изделиях при жарке в пароконвекционных печах

Combination steam ovens, or combi steamers, have entered all spheres of food production, including the meat industry. Their rational use requires a scientific and practical foundation. This research featured the changes in mean volume temperature and temperature gradient that occur in meat products (one-dimensional bodies with different nutrient compositions) during heat treatment in dry air and a steam-air mix.
 The research involved two samples of meat products with different moisture and fat contents. The chicken fillet sample had a moisture content of 74.5% and a fat content of 1.9% while the pork shoulder sample had a moisture content of 55.1% and a fat content of 29.4%. Shaped as a one-dimensional cylinder and a plate, the samples were subjected to heating at the temperature range of 160–240°C in a Unox-203G steam-convection oven (Italy). Dry air and a steam-air mix with a humidity of 80–85% served as a heating medium. The temperature was measured using thermocouples attached to a Sosna-004 meter.
 The research revealed some patterns in the mean volume temperature and temperature gradient. The temperature gradient involved three stages during processing in a steam-air mix and four stages when treated with dry air. The change in the mean volume temperature for the steam-air mix could be described by a power law equation; the dry air treatment was described using a linear equation. When heated in dry air, the rate of change in the temperature gradient was constant at first but started to decrease at a certain stage. The change rate in the mean volume temperature remained low for 5 min and started to increase onwards, maintaining its value until the end of the process. When heated in a steam-air mix, the change rate in the temperature gradient dropped to its minimum in 4–5 min and started to grow. The mean volume temperature demonstrated a high change rate during the first 5 min and went down. The chicken fillet with its low fat content warmed up faster by 13–26% when processed in a steam-air mix and by 9–23% when treated in dry air. The plate-shaped products needed longer heat treatment. The composition and form had no significant effect on the nature of the change in the temperature gradient and mean volume temperature.
 The obtained dependencies made it possible to select the optimal temperature and humidity conditions for convective frying of meat products.

Enhancing the thermostability of the leucine dehydrogenase from Planifilum fimeticola through rational design of the flexible region

LeuDH catalyzes the reversible deamination of L-leucine and certain branched-chain aliphatic amino acids, resulting in the corresponding α-keto acids. This process has received considerable attention in the food and pharmaceutical industries. Although LeuDH from Planifilum fimeticola shows higher catalytic efficiency, its lack of thermostability limits its widespread use in industrial applications. This study identified a mutant, S220P/T347K, with enhanced thermostability through rational design. The experimental results show that under optimal temperature conditions of 65 °C, the half-life (t1/2) of the mutant is 2.94 times longer than that of the wild type, and it does not affect the catalytic activity. Molecular dynamics and 3D structural analysis revealed that the S220P/T347K mutant's increased thermostability mainly results from decreased flexibility, enhanced hydrophobicity, and a favorable electrostatic potential. Furthermore, the mutant's increased catalytic efficiency and specific activity may result from its tighter binding with small molecule substrates. This study is the first to use rational design to modify PfleuDH, effectively enhancing its thermostability and catalytic activity. It provides a simple and effective method for strengthening LeuDH in industrial applications.

Physiological and transcriptomic analysis of tomato in response to sub-optimal temperature stress

ABSTRACT Tomato (Solanum lycopersicum L.) is one of the most important economic crops in China. However, its quality and yield are susceptible to the adverse effects of low temperatures. In our study, two tomato cultivars, showing different tolerance to low temperatures, namely the cold-sensitive tomato cultivar (S708) and cold-tolerant tomato cultivar (T722), were grown at optimal (25/18°C) and sub-optimal (15/10°C) temperature conditions for 5 days. Our study aimed to explore the effect of sub-optimal temperature on fresh weight, chlorophyll content and chlorophyll fluorescence, soluble sugars and proline content of two tomato cultivars. Moreover, we employed RNA-Seq to analyze the transcriptomic response of tomato roots to sub-optimal temperature. The results revealed that S708 showed a more significant reduction in fresh weight, chlorophyll content, photochemical efficiency of PSII (YII), maximum quantum yield of PSII (Fv/Fm), photochemical quenching (qP) and electron transport rate (ETR) compared to T722 under the sub-optimal temperature condition. Notably, T722 maintained higher level of soluble sugars and proline in comparison to S708 uner sub-optimal temperature. RNA-seq data showed that up-regulated DEGs in both tomato cultivars were involved in “plant-pathogen interaction”, “MAPK signaling pathway”, “plant hormone signal transduction”, and “phosphatidylinositol signaling system”. Furthermore, “Amino sugar and nucleotide sugar metabolism” pathway was enriched only in T722. Moreover, under sub-optimal temperature, transcription factor genes and osmoregulation genes showed varying degrees of response in both tomato cultivars. Conclusion: In summary, our results offer detailed insights into the response characteristics of tomato to sub-optimal temperature, providing valuable references for the practical management of tomato crops under sub-optimal temperature condition.

Determination of the oil absorption value of inorganic powder by tracer-assisted headspace gas chromatography

This paper reports a method for determining the oil absorption value of inorganic powder based on tracer-assisted headspace gas chromatographic (HS-GC) technique. The method was carried out by adding 25 μL droplet of toluene-Dioctyl Phthalate solution onto the surface of 1.0 g inorganic powder, then sealing the headspace vial and shaking it to make the powder spherical. The amount of toluene that not been adsorbed by inorganic powder was quantified using HS-GC with the optimal equilibrium temperature and time conditions of 100 °C and 7 min, respectively. A new mathematical model shows that the oil absorption value can be determined from the signal of toluene. The results show that the employed method has good precision (the relative standard deviation < 3.6 %) and accuracy (R2 = 0.993). This method is simple and accurate, and can be an reliable tool for testing the oil absorption value of inorganic powder sample.