Transfer Factor Research Articles

Melting heat transfer and entropy analysis of ternary Casson nanofluids flow with second slip conditions: Application on rocket engine cooling

Heat transfer analysis of Casson nanofluid flow with single and multi-walled carbon nanotubes and Al2O3 or GO nanoparticles, which are suspended in kerosene oil, is elucidated. The impact of second slip conditions on the flow system’s velocity, temperature, and solutal is considered, along with the effect of melting heat transfer and nanoparticle shape factor. The appraisal’s novelty is the incorporation of second slip conditions on kerosene oil flow containing with new three distinct nanoparticles. Similar variables are used to convert the governing equations into ordinary equations which are then solved using homotopy perturbation method (HPM). The profiles of velocity, temperature, concentration, and Bejan number are estimated for various values of relevant parameters. Results demonstrate that the Bejan number declines due to enhance the first thermal parameter and second velocity parameter, while the contrary tendency is examined by raising the Casson fluid parameter and first velocity parameter. Al2O3-SWCNT-MWCNT TNF responds more strongly than GO-SWCNT-MWCNT TNF when the temperature is coupled with (nanoparticles volume fraction, first thermal parameter), axial velocity with (nanoparticles volume fraction, first velocity parameter, first thermal parameter), and Bejan number with melting parameter. This study is to help rocket engine designers identify the optimal nanofluids for cooling and fuel.

Experimental and statistical analysis of heat transfer and friction factor for rectangular-toothed v-cut twisted tapes using TiO2/H2O nanofluid

Experimental and statistical analysis of heat transfer and friction factor for rectangular-toothed v-cut twisted tapes using TiO2/H2O nanofluid

Accumulation of Heavy Metals and Their Genotoxic Potential in Medicinal Plant Verbacsum speciosum Schrad.

Background: Nowadays, the contamination of soil, water, and plants by heavy metals (HMs) presents a notable environmental problem. Methods: Lead (Pb) and zinc (Zn) levels in soil and Verbacsum speciosum populations were measured using atomic absorption spectroscopy, and meiosis in pollen mother cells (PMCs) was examined through the squash technique to evaluate genotoxic effects. Results: The results showed that Pb and Zn concentrations in the soil and, roots, and aboveground portions of all Verbacsum speciosum populations within the mining area exceeded permissible thresholds significantly. Particularly, the contaminated soil displayed average Pb and Zn concentrations of 3527.4±0.7 and 1671.4±0.5 mg/kg, respectively. The roots of Verbacsum speciosum plants closest to the mine exhibited the highest levels of Pb and Zn, measuring 204±0.05 mg/kg and 570±0.16 mg/kg, respectively. Additionally, the above-ground parts of the plants showed Pb and Zn concentrations of 312±0.12 mg/kg and 519±0.17 mg/kg, respectively. Moreover, the transfer factor (TF) for both Pb and Zn was found to be above one, indicating substantial accumulation of these metals in the above-ground portions. The presence of Pb and Zn also resulted in abnormalities during meiosis. As the distance from the mine increased, a decrease in the occurrence of meiosis abnormalities and an increase in the meiotic index (MI) were observed. Conclusion: These results highlight the potential risks to human health posed by industrial wastewater and the natural presence of HMs in soil. The ability of these metals to accumulate in plants and interfere with their meiosis underscores the importance of addressing and mitigating these hazards.

Transfer of heavy metals from soil to vegetables: A comparative assessment of different irrigation water sources

This study aimed to assess the transfer factor (TF) of heavy metals (HMs) from soil to commonly consumed vegetables irrigated with different water sources. The field study covered 36 m2 of agricultural land in Kermanshah province, Iran, divided into nine equal-sized plots. Coriander, basil, and radish were the three types of vegetables cultivated and subjected to irrigation over two months, utilizing three different water sources: treated wastewater effluent (TWE), river water (RW), and well water + nitrogen fertilizer (WWF). After the irrigation and harvesting stages, soil samples from the cultivation area and harvested vegetables were collected. These samples underwent analysis using the ICP-OES method to assess HM levels and subsequent calculation of the TF of HMs from soil to plants. The results revealed that the TF levels indicated plants' relatively weak response (TF < 1) to the absorption of HMs. For non-toxic elements (Mn, Fe, Zn, Cu, Ni), TF values were generally higher than those for toxic elements (Cd, As, Pb) across all three vegetable types and irrigation treatments. The study's findings suggest that the TF of HMs in the studied vegetables varied based on the irrigation source and vegetable type. Various factors, including the type of irrigation source and vegetable, influenced the TF of HMs, each having different impacts on the transfer rate of each HM. The study highlights the importance of monitoring irrigation water and soil quality to prevent the accumulation of HMs in cultivated vegetables, thereby mitigating potential risks to human health.

A longitudinal assessment of factors affecting training transfer among new clinical nurse specialists

ObjectiveThis study aimed to explore the determinants influencing training transfer and evaluate how those factors change over time among nurses who graduated from clinical nurse specialist training to provide a theoretical basis for improving the training transfer of clinical nurse specialists (CNSs). MethodsA quantitative longitudinal survey with four rounds of data collection was utilized to measure the influencing aspects of training transfer from June 2018 to December 2019. A total of 46 new CNSs participated in this study, including 30 and 16 nurses receiving training programs for CNSs in Infusion, Wound and Ostomy. The factor influencing training transfer (FITT) questionnaire was used to collect data for the first month (time 1), the third month (time 2), the sixth month (time 3), and the first year (time 4) after training. This questionnaire contains 53 items divided into five dimensions, including managerial support (20 items); hindrance in the organization (6 items); the validity of the training program (10 items); organizational and personal facilitators (11 items); and personal attitudes towards training transfer (6 items). ResultsThe influencing factors of CNSs transfer decreased over time, with managerial support, hindrance in the organization, the validity of the training program, and personal attitudes towards training transfer changing statistically over time (P < 0.05), and no statistical difference in organizational and personal facilitators over time (P = 0.229). During early after training (the first month and the third month after training), hindrance in the organization is the biggest obstacle to training transfer. During the later of training (the sixth month and first year after the training), managerial support is the biggest obstacle to training transfer. Overall level of influencing factors of training transfer decreased in three months after training among Infusion nurses (P < 0.001), and Wound and Ostomy nurses decreased in the first year after training (P < 0.001). ConclusionsThe trend and level of training transfer predictors decreased depending on time. Clarifying the factors influencing transfer and its patterns may help nursing managers enhance the implementation and impact of nurse specialist training.

Clinical efficacy of ganciclovir combined with transfer factor oral solution for pediatric infectious mononucleosis

This study investigates the clinical efficacy of ganciclovir combined with transfer factor oral solution in the treatment of patients with infectious mononucleosis (IM) to provide a reference for clinical application. A total of 150 children with IM who received treatment in our hospital from 2020 to 2022 were randomly selected as the research subjects. They were randomly divided into a control group receiving intravenous administration of ganciclovir (n = 75) and an observation group receiving transfer factor oral liquid in combination with intravenous administration of ganciclovir (n=75). The results showed that after treatment, the serum levels of CK-MB, CK, CRP, IL-6, and TNF-α were significantly reduced in both groups. The observation group showed lower levels than the control group. Additionally, peripheral blood CD4+ T cells, CD4+/CD8+ ratio, and Tfr expression were higher in the observation group compared to the control group, while the level of CD8+ T cells was lower than that of the control group. Furthermore, there were no significant changes in the levels of IgA, IgM, and IgG antibodies in the two groups before and after treatment. In conclusion, the combination therapy of transfer factor oral solution and ganciclovir demonstrates favorable clinical efficacy and safety in the treatment of children with IM, as it effectively reduces inflammatory reactions, regulates cellular immune function, promotes Tfr differentiation, and shortens recovery time.

Dynamic hierarchical partitioning method of flexible resource for virtual power plant based on event triggering

Abstract With the advantage of efficient aggregation of flexible resources on the demand side, virtual power plants have been widely considered as one of the effective solutions to solve the lack of large-scale access systems and regulation capacity of new energy. Aiming at the problem of how the flexible resources of the virtual power plant can effectively participate in the optimal operation of hierarchical zoning of the power grid, this paper takes the aggregation of flexible resources of the virtual power plant to alleviate multiple line overload as an example. By deducing the transfer factor matrix under the linearized AC power flow model, an event-triggered hierarchical zoning method of flexible resources of virtual power plants considering resource effectiveness is proposed. The effectiveness of the algorithm is verified in several network examples, which provides a new idea for the virtual power plant to participate in the optimal operation of various levels and regions of the power grid.

FOT Technique Applied for Monitoring of COVID-19 Pneumonia Reveals Small Airways Involvement.

The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional character of hypoxia. We hypothesize that such effects could be explained by the closure of small airways. To prove the hypothesis, we evaluated the patency of small airways in 30 oxygen-dependent, spontaneously breathing patients with SARS-CoV-2 pneumonia during their hospital stay using the FOT method and then compared the results with data obtained three months later. During the acute period, total resistance (R5) and peripheral resistance (R5-20) rose above the upper limit of normal (ULN) in 28% and 50% of all patients, respectively. Reactance indices X5, AX and Fres exceeded ULN in 55%, 68% and 66% of cases. Significant correlations were observed between PaO2/FiO2, the time spent in the hospital and R5, X5, AX and Fres. After 3 months, 18 patients were re-examined. During the hospital stay, 11 of them had risen above the upper limit of normal (ULN), for both resistance (R5-20) and reactance (X5, AX) values. Three months later, ULN for R5-20 was exceeded in only four individuals, but ULN for X5 and AX was exceeded in five individuals. Lung function examination revealed a combined restrictive/obstructive ventilatory failure and reduced CO transfer factor. We interpret these changes as lung tissue remodeling due to the process of fibrosis. We conclude that during acute period of SARS-CoV-2 pneumonia, dilated pulmonary blood vessels and parenchymal oedema induce functional closure of small airways, which in turn induce atelectasis with pulmonary right-to-left shunting, followed by the resulting hypoxemia.

Analysis of spatial patterns and influencing factors of farmland transfer in China based on ESDA-GeoDetector

Farmland transfer is a critical component in facilitating agricultural scale management and improving agricultural production efficiency. This study examines the spatial distribution of farmland transfer in China and identifies the factors influencing it, offering valuable guidance for advancing China’s farmland transfer practices. Through the application of mathematical statistics and GIS spatial analysis, the study investigates changes in spatial patterns related to the scale, rate, mode, and recipients of farmland transfer across China's 30 provinces from 2015 to 2020. Geographical detectors are also employed to identify the key factors influencing the extent and pace of farmland transfer. The study reveals that between 2015 and 2020, China's farmland transfer area increased from 29,789 to 37,638 million hectares. Provinces with abundant farmland resources generally experienced larger farmland transfers, while economically developed regions and major grain-producing areas saw higher rates of farmland transfers. The predominant mode of farmland transfer in China was leasing (subcontracting), accounting for over 80% of the total transferred area. Large-scale grain growers and family farms were significant participants in farmland transfers, acquiring approximately 60.1% of the transferred lands, followed by professional cooperatives (21.5%), enterprises (10.4%), and other entities (7.9%). Key factors influencing the farmland transfer area include the "regional farmland area", the "proportion of family farms supported by loans", and the "proportion of non-agricultural population", with explanatory powers of 0.663, 0.319, and 0.225, respectively. Notably, there is a substantial interaction between the "regional farmland area" and factors such as the "proportion of family farms supported by loans" and the "grain yield per unit area", with explanatory powers reaching 0.957 and 0.901, respectively. These findings offer valuable insights for promoting farmland transfer in agriculturally rich regions. Factors affecting the farmland transfer rate include "grain yield per unit area", "GDP per capita", and the "proportion of non-agricultural population", each with an explanatory power above 0.500. Moreover, their interactive explanatory powers with other indicators exceed 0.600, indicating that provinces with high agricultural productivity or economic development levels are more likely to undergo farmland transfer. The paper concludes by proposing strategies and recommendations to promote farmland transfer in both "large agricultural areas" and "metropolitan suburbs."

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) under flooded and unflooded conditions in Hanoi, Vietnam

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) in Hanoi, Vietnam have been investigated using a low background gamma spectrometer with an HPGe detector (Model-GC5019). Twenty pairs of soil and water spinach samples in two environmental conditions, i.e., flooded and unflooded, were collected for measuring the activity concentrations and determining the soil-to-plant transfer factors (TFs) of natural radionuclides. For water spinach, stems and leaves were collected as the main parts for human consumption and livestock food. The TF of 40K is within the range of 0.32–2.49, which is greater than that of 228Ra (0.01–0.17) and 226Ra (0.01–0.13). The geometric means (geometric standard deviations) of the TFs are 1.17(1.89), 0.05(2.41) and 0.04(1.88) for flooded sites, and 0.89(1.73), 0.03(2.12) and 0.03(1.82) for unflooded sites, respectively. Comparing between the flooded and unflooded sites, the TFs are all greater at the flooded sites.

Investigation of radioactivity concentrations and soil-to-plant transfer factors in soil samples taken from different distance zones to the Metsamor nuclear power plant

Abstract Monitoring radioactivity around nuclear power plants is important to avoid the risks of radiation. This study provides an overview of the radioactive emission impact on the near surroundings of the Metsamor nuclear power plant in Armenia. In this context, 29 soil samples were collected from the 40, 80, 120, 160 km radius areas determined in the direction of Iğdır province by accepting the Metsamor nuclear power plant as the center. The activity concentrations of 226Ra, 232Th, 40K and 137Cs in soil samples ranged from 7.90 to 23.44, 7.11 to 33.55, 132.54 to 502.69 and 0.33 to 17.61 Bq/kg, respectively. In addition, the radioactivity concentrations in some agricultural products and the transfer factors from soil to plant were determined. As a result, there is no significant radiological risk in terms of studied radioisotopes for people living in this region.

Concentration of heavy metals in soil and leaves of Conocarpus Erectus Tree: A Biomonitoring Study, Ahvaz, Iran.

Heavy metals biomonitoring was performed using the Conocarpus erectus tree in Ahvaz city. Composite leaf and soil samples were collected from 23 selected stations. The concentrations of heavy metals (Pb, Zn, Cd, Cu, Fe and Mn) in leaf and soil samples, and bioavailability of metals in soil samples were determined. Examination of soil physicochemical parameters proved neutral to slightly alkaline nature, and low organic matter content in the soil samples. The mean concentration of heavy metals in soil was: Fe > Mn > Zn > Pb > Cu. Ecological risk assessment of heavy metals was in the range of safe to low risk (RI < 150). Although the concentration of metals in the more polluted areas was higher in both leaf and soil samples, there was no significant relationship between the concentrations of metals in the leaf and soil samples. This relationship is even lower between the bioavailable component of metals in the soil and the concentration of metals in the leaves. Transfer factor values based on total contents of metals in soil samples indicated that Conocarpus erectus is mostly contaminated with Zn and Cu. The results of Accumulation factor of plant revealed that Pb, Zn, and Fe were mostly enriched in the plant by anthropogenic activities. MAI values in heavy and light traffic, and industrial areas were 11.88, 8.01 and 8.15, respectively. In general, it is evident that the Conocarpus erectus leaves accumulate heavy metals in polluted areas, so it can be used as a bioindicator of air pollution with heavy metals in regions with similar conditions.

Effect of particle size and application rate of steel (Linz-Donawitz, LD) slag on heavy metal built-up in soil and their transfer dynamics in spinach (Spinacia oleracea L.)

Linz-Donawitz (LD) slag is a solid industrial waste generated during the production of steel. In general, the amount of LD slag produced varies from 300 to 400 kg ton-1 of steel. Presently only 25 % of the steel slag, which is also rich in various macro and micro-nutrients, is being reused in India compared to 70–100 % in other countries. The present study deals with the possibility of utilizing LD slagas a nutrient rich low-cost soil conditioner in agriculture. An experiment was thus conducted to determine the effect of LD slag application at rates 0.25, 0.50 and 1 t ha-1 in two particle sizes i.e., <50 and <100 microns (µ) on spinach (Spinacia oleracea L.). Physico-chemical, biological characteristics and heavy metals in soil and latter’s transfer from soil to the foliage was also determined. The results showed that an application of LD slag @1 tha-1 and 100 µ particle size significantly improved the soil microbial count and activity of enzymes such as dehydrogenase and phosphatase while at a smaller particle size of LD slag (50 µ) @ 1 tha-1, a significant increase in the foliage yield of spinach was observed. The risk due to heavy metals present in the steel slag as evidence by indicator of heavy metal content in plants i.e. transfer factor (TF), hazard quotient (HQ) and hazard index (HI) was within the permissible range. However long-term effect of steel slag application on ecotoxicity and phytotoxicity levels must be deciphered. In conclusion the application of LD slag in spinach does not negatively impact the soil health and in fact causes an increase in the economic yield of spinach.

Effects of Returning Green Manure-Chinese Milk Vetch on the Availability and Transformation of Zinc in Purple Tidal Mud Soil under Rice Cultivation

This study aimed to investigate the impact of different levels of Chinese milk vetch (Astragalus sinicus L.) incorporation on the availability and transformation of zinc in purple tidal mud soil under rice cultivation. A two-year pot experiment was conducted, comprising seven treatments: a control group without fertilizer, a control group with Chinese milk vetch application, a control group with chemical fertilizer application, and four treatment groups with varying levels of Chinese milk vetch application following chemical fertilizer application. Results showed that Chinese milk vetch application increased the content of available zinc (DTPA-Zn) in purple tidal mud soil. Sole application of Chinese milk vetch ultimately enhanced the transfer factor of zinc in purple tidal mud soil and reduced the distribution index. However, applying Chinese milk vetch after chemical fertilizer application ultimately decreased the transfer factor of zinc and increased the distribution index. Furthermore, sole application of Chinese milk vetch facilitated the conversion of zinc in purple tidal mud soil into available forms, while applying it after chemical fertilizer application promoted the transformation of zinc into ineffective forms, with a greater conversion observed at higher levels of Chinese milk vetch application.

Soil-to-plant transfer factor of natural radionuclides and associated health risk in some vegetable species in arid area

Soil-to-plant transfer factor of natural radionuclides and associated health risk in some vegetable species in arid area

Optimizing cardiopulmonary rehabilitation duration for long COVID patients: an exercise physiology monitoring approach

The presence of prolonged symptoms after COVID infection worsens the workability and quality of life. 200 adults with long COVID syndrome were enrolled after medical, physical, and mental screening, and were divided into two groups based on their performance. The intervention group (n = 100) received supervised rehabilitation at Department of Pulmonology, Semmelweis University with the registration number 160/2021 between 01/APR/2021–31/DEC/2022, while an age-matched control group (n = 100) received a single check-up. To evaluate the long-term effects of the rehabilitation, the intervention group was involved in a 2- and 3-month follow-up, carrying out cardiopulmonary exercise test. Our study contributes understanding long COVID rehabilitation, emphasizing the potential benefits of structured cardiopulmonary rehabilitation in enhancing patient outcomes and well-being. Significant difference was found between intervention group and control group at baseline visit in pulmonary parameters, as forced vital capacity, forced expiratory volume, forced expiratory volume, transfer factor for carbon monoxide, transfer coefficient for carbon monoxide, and oxygen saturation (all p < 0.05). Our follow-up study proved that a 2-week long, patient-centered pulmonary rehabilitation program has a positive long-term effect on people with symptomatic long COVID syndrome. Our data showed significant improvement between two and three months in maximal oxygen consumption (p < 0.05). Multidisciplinary, individualized approach may be a key element of a successful cardiopulmonary rehabilitation in long COVID conditions, which improves workload, quality of life, respiratory function, and status of patients with long COVID syndrome.

Investigation on the thermal and hydraulic characteristics of the micro heat sinks with grooves and pin fins by Taguchi-based sensitivity analysis

The heat dissipation issue of the micro electronic devices seriously restricts their application in the aerospace, national defense, communication, etc. The novel heat sinks with trapezoidal grooves and rectangular pin fins are proposed to meet the cooling requirement of the high-power devices. The cooling effect, thermohydraulic characteristics, total efficiency and thermodynamic performance of the heat sinks are studied by three-dimensional numerical simulation. Firstly, the influence of the relative position between the grooves and the pin fins on the thermohydraulic performance is explored in detail. Secondly, Taguchi optimization and analysis of variance are adopted to quantitatively analyze the impact degree of the pin fin width, length and height on the Nusselt number, friction factor and total performance index. The optimal structures are obtained for different objectives. Lastly, the temperature performance, total performance and the irreversibility of the optimal structures are compared thoroughly. New findings include that: the best arrangement of the grooves and pin fins is obtained, which enhances the Nusselt number by 1.5 times compared to the smooth heat sink. The fin width is the most critical factor for the heat transfer and flow, while the fin length shows the greatest importance in the overall performance. The optimized heat sink with the fin width of 50 μm, length of 60 μm and height of 150 μm reduces the peak temperature by 12.3 ℃ compared to the smooth heat sink for Reynolds number of 303. This heat sink yields the highest total performance index with 1.43 for Reynolds number of 368 and significantly reduces the irreversible loss. Moreover, the optimized heat sink with the fin width of 10 μm, length of 60 μm and height of 100 μm reduces the friction factor by 61.39 % compared to the original structure for Reynolds number of 635, which is beneficial to reduce the energy consumption. The quantitative analysis of the parameter sensitivity for novel heat sinks reveals the mechanism of the heat transfer enhancement by modifying the geometric parameters and provides an effective solution for thermal management of the high-power devices.

Long-term behaviour of Cs-137, Cs-133 and K in beech trees of French forests

In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40–50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.

Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms.

Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes is one of the most important factors for efficient electron transfer; this is possible due to the production of type IV pili and c-type cytochromes that allow it to carry out extracellular electron transfer (EET) to final acceptors. In this study, we analyzed the biofilm formed on different support materials (glass, hematite (Fe2O3) on glass, fluorine-doped tin oxide (FTO) semiconductor glass, Fe2O3 on FTO, graphite, and stainless steel) by G. sulfurreducens DL1 (WT) and GSU1771-deficient strain mutant (Δgsu1771). GSU1771 is a transcriptional regulator that controls the expression of several genes involved in electron transfer. Different approaches and experimental tests were carried out with the biofilms grown on the different support materials including structure analysis by confocal laser scanning microscopy (CLSM), characterization of electrochemical activity, and quantification of relative gene expression by RT-qPCR. The gene expression of selected genes involved in EET was analyzed, observing an overexpression of pgcA, omcS, omcM, and omcF from Δgsu1771 biofilms compared to those from WT, also the overexpression of the epsH gene, which is involved in exopolysaccharide synthesis. Although we observed that for the Δgsu1771 mutant strain, the associated redox processes are similar to the WT strain, and more current is produced, we think that this could be associated with a higher relative expression of certain genes involved in EET and in the production of exopolysaccharides despite the chemical environment where the biofilm develops. This study supports that G. sulfurreducens is capable of adapting to the electrochemical environment where it grows.

Radionuclide Transfer in Tea Cultivation: Assessing Radiological Risks in the Largest and First Established Tea Garden in Bangladesh

ABSTRACT To address potential health risks associated with radioactivity in tea consumption, a study was conducted utilizing high purity germanium (HPGe) γ-ray spectrometry to measure the concentrations of 226Ra, 232Th, 40K, and 137Cs radionuclides in soil and tea leaves collected from several major tea gardens (including the Malnicherra tea garden which is the largest and first established tea garden in the Indian subcontinent) situated in Sylhet, Bangladesh. Although nearly all soil samples showed the presence of 137Cs (with a maximum activity of 6.5 ± 1.31 Bq/kg), none of the analyzed tea leaf samples exhibited its presence, which can be attributed to its restricted transferability from soil to plants. The range of transfer factors for 226Ra, 232Th and 40K from soil to tea leaves was calculated to be (0.39–0.54), (0.25–0.46) and (1.39–3.03), respectively. The heightened concentrations of 40K identified in the tea leaf samples can be mainly ascribed to specific metabolic processes associated with potassium, along with the heightened utilization of potassium chloride-based fertilizers aimed at enhancing tea production. The examination of hazard parameters, including the estimated committed effective dose and the excess lifetime cancer risk associated with tea consumption, reveals values that are comparatively lower than the recommended limits. Consequently, the radiation exposure from tea consumption does not present a significant radiological health concern for the general population.