Exposure Dose Research Articles

Investigation of radiation doses and dose constraint values of nonmedical planned exposure radiation practices in Taiwan

In Taiwan, the Nuclear Safety Commission (NUSC) is the competent authority responsible for ensuring the safety of ionizing radiation operations. In recent years, the NUSC has introduced the concepts of ALARA and dose constraints (as recommended by the International Commission on Radiological Protection), to control the radiation safety of various radiation sources, and to review the protective control measures. Consideration of these concepts can help ensure that industry operators optimize radiation protection in planned exposure situations. This study investigated the occupational exposure of facility operators using nonmedical planned exposure radiation sources in Taiwan. The NUSC provided a sampling roster, and survey respondents were randomly selected. An on-site radiation safety survey was conducted using a calibrated handheld radiation survey meter to measure the doses that radiation workers were exposed to during normal operations. In addition, the dose constraints of multiple radiation practices were evaluated through the statistical analysis of dose data. From 2020 to 2023, on-site radiation dose surveys were conducted on 1614 radiation sources. Additionally, the average occupational exposure doses of workers in relation to multiple nonmedical radiation operations were evaluated, and recommended dose constraints for these operations were proposed.

DEVELOPMENT OF AN APPLICATION FOR ASSESSING PUBLIC RADIATION EXPOSURE WHEN LIVING AND CARRYING OUT ANY ACTIVITIES AT THE SEMIPALATINSK TEST SITE

The article presents an overview of capabilities of developed software ‘Assessment of public radiation exposure when living and carrying out any activities at the Semipalatinsk Test Site’ and quoted the algorithm to calculate public individual annual effective exposure doses from the major dose-forming man-made radionuclides at the test site (137Cs, 90Sr, 239+240Pu, 241Am, 3H). The software developed takes into account such behavior scenario as a farmer engaged in subsistence farming and living in the study area together with his family members. The software was developed for Windows operating system and implemented in the development framework of cross-platform applications Embarcadero Delphi XE7 Professional in the object-oriented programming language Object Pascal.

Absolute Method for Measuring Environmental Radioactive Materials Using Imaging Plates

Abstract We had previously developed a measurement method using an imaging plate (IP) to evaluate and address surface contamination caused by the release of radioactive materials during the Fukushima nuclear accident. The measurement units for the surface contamination density were in relative values [described as relative luminescence levels measured in luminescence arbitrary units (LAU)], but the evaluation was required in absolute values, such as Bq cm−2, to enable appropriate control of exposure doses. This study establishes a method for converting the IP measurements of surface contamination density due to environmental radioactivity into absolute values. Soil contaminated with radioactive materials from the Fukushima nuclear accident was collected to create a working reference material (WRM). The conversion coefficient for surface contamination density was calculated using the WRM values measured with an IP and high-purity germanium detectors. The IP measurement values were converted into the surface contamination density using the conversion coefficient. The WRM values measured with the IP and high-purity germanium detectors were 324.1 LAU and 32.22 ± 2.27 Bq cm−2, respectively. The surface contamination density conversion factor was calculated as 0.0994. The surface contamination density on the roof of the Tsukuba City facility was re-evaluated using the conversion factor. The average value of 29,972 Bq m−2 matched the amount of radioactive material fallen in Tsukuba City. By standardizing the measurement conditions for surface contamination when using IPs, we successfully quantified the surface contamination density with an accuracy comparable to that of conventional methods. This method is expected to make a significant contribution to efficient radiation safety management.

Associations between fine particulate matter, gene expression, and promoter methylation in human bronchial epithelial cells exposed within a classroom under air-liquid interface

Associations between indoor air pollution from fine particulate matter (PM with aerodynamic diameter dp < 2.5 μm) and human health are poorly understood. Here, we analyse the concentration-response curves for fine and ultrafine PM, the gene expression, and the methylation patterns in human bronchial epithelial cells (BEAS-2B) exposed at the air-liquid interface (ALI) within a classroom in downtown Rome.Our results document the upregulation of aryl hydrocarbon receptor (AhR) and genes associated with xenobiotic metabolism (CYP1A1 and CYP1B1) in response to single exposure of cells to fresh urban aerosols at low fine PM mass concentrations within the classroom. This is evidenced by concentrations of ultrafine particles (UFPs, dp < 0.1 μm), polycyclic aromatic hydrocarbons (PAH), and ratios of black carbon (BC) to organic aerosol (OA). Additionally, an interleukin 18 (IL-18) down-regulation was found during periods of high human occupancy.Despite the observed gene expression dysregulation, no changes were detected in the methylation levels of the promoter regions of these genes, indicating that the altered gene expression is not linked to changes in DNA methylation and suggesting the involvement of another epigenetic mechanism in the gene regulation.Gene expression changes at low exposure doses have been previously reported. Here, we add the possibility that lung epithelial cells, when singly exposed to real environmental concentrations of fine PM that translate into ultra-low doses of treatment, may undergo epigenetic alteration in the expression of genes related to xenobiotic metabolism.Our findings provide a perspective for future indoor air quality regulations. We underscore the potential role of indoor UFPs as carriers of toxic molecules with low-pressure weather conditions, when rainfall and strong winds may favour low levels of fine PM.

A sub-pharmacological test dose does not predict individual docetaxel exposure in prostate cancer patients.

Docetaxel is a cytotoxic drug used for first-line treatment of various malignancies. It has a narrow therapeutic index and shows wide interpatient variability in clearance and toxicity. Tools for individual dose optimization are needed to maximize efficacy and avoid toxicity. We performed a proof-of-concept study (EudraCT 2016-003785-77) to evaluate whether pharmacokinetics after a sub-pharmacological test dose of 1000µg docetaxel (millidose) could be used to predict therapeutic dose exposure. Thirty prostate cancer patients eligible for treatment with docetaxel as part of routine clinical care were included. An intravenous docetaxel millidose was administered 1-7 days prior to therapeutic docetaxel. After both doses plasma docetaxel concentrations were measured by ultra- high performance liquid chromatography-tandem mass spectrometry. The docetaxel clearance was estimated with non-linear mixed effects modeling. Geometric mean docetaxel clearance was 57.9L/h (GCV 78.6%) after admission of a millidose and 40.3L/h (GCV 60.7%) after admission of a therapeutic dose. The millidose and therapeutic dose in a single patient were not significantly correlated (Spearman's rho R = 0.02, P = 0.92). Docetaxel pharmacokinetics at milli- and therapeutic dose level showed insufficient correlation for individual dose optimization. However, the clearance of a docetaxel millidose and full dose are within the same order of magnitude. Therefore, docetaxel millidose pharmacokinetics could potentially facilitate prediction of docetaxel pharmacokinetics at a population level in situations where therapeutic dose levels are impractical, such as pharmacokinetic drug-drug interaction studies or pediatric studies.

Edge smoothness enhancement of digital lithography based on the DMDs collaborative modulation

The rough saw-tooth edge caused by the inherent microstructures of digital micromirror device (DMD) will reduce the quality of the lithography pattern. Comprehensively considering the manufacturing efficiency, precision and cost, we propose a DMDs collaborative modulation lithography method to improve the smoothness of the lithography pattern edge. Through combining two misaligned DMDs to collaboratively modulate exposure dose, the better edge smoothness can be achieved. Collaborative exposure with 1/2 DMD pixel misalignment and 1/4 DMD pixel misalignment are both implemented to form the step-shape lithography patterns. The experimental results show that the saw-tooth edge can approximate to a straight line when increasing the number of times of the collaborative exposure. Further error analysis indicates it is effective to improve the edge smoothness while ensuring the lithography quality by using the collaborative modulation lithography. These results indicate that the DMDs collaborative modulation lithography is a promising technique for fabrication of microstructures, which may be a solution for balancing the fabrication precision, efficiency and cost.

Laser Machining at High ∼PW/cm2 Intensity and High Throughput

Laser machining by ultra-short (sub-ps) pulses at high intensity offers high precision, high throughput in terms of area or volume per unit time, and flexibility to adapt processing protocols to different materials on the same workpiece. Here, we consider the challenge of optimization for high throughput: how to use the maximum available laser power and larger focal spots for larger ablation volumes by implementing a fast scan. This implies the use of high-intensity pulses approaching ∼PW/cm2 at the threshold where tunneling ionization starts to contribute to overall ionization. A custom laser micromachining setup was developed and built to enable high speed, large-area processing, and easy system reconfiguration for different tasks. The main components include the laser, stages, scanners, control system, and software. Machining of metals such as Cu, Al, or stainless steel and fused silica surfaces at high fluence and high exposure doses at high scan speeds up to 3 m/s were tested for the fluence scaling of ablation volume, which was found to be linear. The largest material removal rate was 10 mm3/min for Cu and 20 mm3/min for Al at the maximum power 80 W (25 J/cm2 per pulse). Modified surfaces are color-classified for their appearance, which is dependent on surface roughness and chemical modification. Such color-coding can be used as a feedback parameter for industrial process control.

Unfavorable Outcomes Associated With Glucocorticoid Use in Current Standard-of-Care Management of Systemic Lupus Erythematosus in Canada.

Our objective was to describe the administration of glucocorticoids (GCs) and characterize its association with organ damage in a longitudinal systemic lupus erythematosus (SLE) cohort over a time period spanning the introduction of biologics in Canada. A retrospective observational study was conducted using data from a large SLE cohort in Canada, including adults without lupus nephritis or central nervous system lupus. Patients were observed from time of entry into the cohort to the last available clinic visit (up to December 31, 2020), with a minimum of 24 months of follow-up. Demographic and clinical characteristics, including average disease activity, treatment administration, and prevalence of organ damage, were examined. Organ damage was stratified by GC administration. A total of 1,255 patients were included. The mean follow-up duration was 10.5 (SD 8.6) years. One hundred eighty-two (15%) patients had organ damage at baseline. More than 80% of patients were prescribed GCs over the follow-up period, almost all patients had long-term GC treatment, and only 5% of patients took any biologics. Organ damage was more frequent in patients with a higher average GC dose and greater years of GC exposure. In this large cohort of patients with SLE, the majority of patients continue to rely on GC for SLE symptom management, with limited administration of biologics. GC administration was correlated with increased irreversible organ damage. Access to novel GC-sparing treatment options is critical to improve long-term outcomes for patients with SLE, especially given the continued reliance on GC despite the introduction of biologics.

Effect of electrophysical treatments on the storage life of potatoes and other vegetable crops

To prevent the progression of various infectious diseases, seed and planting material must undergo treatment with ultraviolet (UV) radiation at an intensity of 10-15 kilojoules. This necessitates studying the impact of UV radiation on products as they move in a flow along a conveyor belt. (Research purpose) The study aims to evaluate the feasibility of using ultraviolet radiation to improve the storage indicators of potato and other vegetable crops. It also assesses the technological parameters in both laboratory and production settings to ensure a reduction in contamination. (Materials and methods) To determine the optimal technological parameters of a machine for processing vegetable crops and potatoes before storage in the post-harvest processing system, an experimental installation was created and the electrophysical effects on storage quality indicators were examined. For the study, the most common vegetable crop varieties were selected, in particular, Lady Rosetta potato, Vitaminnaya-6 table carrot and Bordeaux 237 table beet. These crops are cultivated under various soil and climatic conditions across the Russian Federation. (Results and discussion) A methodology has been developed to assess the quality of seed material after the storage period, including the justification for the time interval, air mixture temperature parameters and ultraviolet radiation optical modes. The optimal parameters for processing potato tubers, carrots, and beets have been determined. The study examined the impact of ultraviolet exposure with established parameters on the disease development in carrot and beet crops, caused by the studied phytopathogenic microorganisms at temperatures of 2 and 25 degrees Celsius. (Conclusions) The indicators of the spread and development of infectious diseases in the studied vegetable crops show a decline trend when the translational speed of root crop movement is 0.7 meters per second, the interaxial distance between ultraviolet radiation sources is 0.1 meters, the distance from the sources to the roller surface of the conveyor belt is 0.05 meters, and a constant dose of ultraviolet exposure is applied.

Local fractal and wavelet analysis of aerogeophysical data: An integrated approach in target generation of Cu-Au-Fe skarn and gold-polymetallic epithermal porphyry-related systems in eastern Transbaikalia, Russia

Three geophysical fields (anomalous magnetic, exposure dose rate, and apparent resistance) were investigated by local fractal and two-dimensional wavelet analyses for ore prospectivity mapping (scale 1:25000). The study region is part of the Gazimuro-Zavodsky gold-polymetallic ore district (Transbaikalia, South-East Russia) and includes 9 recognized hypogene ore deposits and 40 ore occurrences of Au, Fe, Cu, Pb, W, Sb, As, boron, talc, and fluorite (skarn and hydrothermal formations related to felsic and mafic magmatism). The results show that fractal and wavelet analyses of the geophysical fields demonstrate a certain specialization in the delineation of different mineralization types. The best prospective efficiency (in terms of quality/cost) was achieved by integrating the six individual prospective maps using the ensemble approach.

Chest CT-IQA: A multi-task model for chest CT image quality assessment and classification

In recent years, especially during the COVID-19 pandemic, a large number of Computerized Tomography (CT) images are produced every day for the purpose of inspecting lung diseases. However, the diagnosis accuracy depends on the quality of CT imaging and low quality images may greatly affect clinical diagnosis, resulting in misdiagnosis. It is difficult to effectively rate the quality of massive CT images. To solve the above problems, we first constructed a dataset of 800 CT volumes for chest CT image quality assessment. Then we propose a multi-task model for chest CT image quality assessment and classification. This model can automatically classify CT image sequences of different visual inspection windows, and automatically estimate CT image quality score, to match the visual score from clinicians. The experimental results show that the window classification accuracy and the dose exposure classification accuracy of our model can reach 0.8375 and 0.8813 respectively. The Pearson Linear Correlation Coefficient (PLCC) and Root Mean Square Error (RMSE) between the model prediction results and the two radiologist’s annotation average result reached 0.3288 and 1.9264. It shows that our model has a potential to mimic quality evaluation of experts.

Fetal dose assessment in a pregnant patient with brain tumor: A comparative study of proton PBS and 3DCRT/VMAT radiation therapy techniques.

The treatment of brain tumors in pregnant patients poses challenges, as the out-of-field dose exposure to the fetus can potentially be harmful. A pregnant patient with prior radiation treatment was presented with a brain tumor at our clinic. This work reports on our pre-treatment study that compared fetal dose exposure between intensity-modulated proton therapy (IMPT) using pencil beam scanning (PBS) and conventional photon 3D conformal radiation therapy (3DCRT) and volumetric-modulated arc therapy (VMAT), and the subsequent pregnant patient's radiation treatment. Pre-treatment measurements of clinical plans, 3DCRT, VMAT, and IMPT, were conducted on a phantom. Measurements were performed using a device capable of neutron detections, closely following AAPM guidelines, TG158. For photon measurements, fetus shielding was utilized. On patient treatment days, which was determined to be proton treatment, shielding was used only during daily imaging for patient setup. Additionally, an in vivo measurement was conducted on the patient. Measurements showed that IMPT delivered the lowest fetal dose, considering both photon and neutron out-of-field doses to the fetus, even when shielding was implemented for photon measurements. Additionally, the proton plans demonstrated superior treatment for the mother, a reirradiation case. The patient was treated with proton therapy, and the baby was subsequently delivered at full term with no complications. This case study supports previous clinical findings and advocates for the expanded use of proton therapy in this patient population.

Seasonal variation in exposure to particulate matter among children attending different levels of education: Comparison of two dosimetry models

Exposure to particulate matter (PM) has been associated with several adverse health outcomes. Studies indicate that children may be exposed to much higher concentrations of PM at school than in other environments. There exists very little data on the deposited dose of PM while children attend classes. This study was carried out in a school located near an industrial complex in Portugal and attended by children aged 3–12 years. Indoor PM10, PM2.5 and PM1 were measured over two seasons in classrooms representing different school year groups. Particle deposition fractions in the respiratory tract, as well as the deposited doses, were calculated using the Multiple-Path Particle Dosimetry (MPPD) and the Exposure Dose Model (ExDoM2). Both models were implemented assuming an 8-h exposure scenario to represent the school day. In general, differences in PM concentrations were observed depending on room occupancy periods and season. The highest mean PM2.5 concentration was recorded in winter when the classroom was vacant (23.7 ± 20.5 μg m−3), while the highest mean PM10 level was observed in spring during school hours (61.7 ± 24.2 μg m−3). Regardless of the dosimetry model, the highest deposition of PM10 and PM2.5 was in the upper region, while the lowest was in the tracheobronchial (TB) region. The results indicate that deposited dose and deposition fraction in spring may be more harmful to pupils’ health than in winter. PM10 presented the highest doses, ranging from 54.2 to 128 μg and from 83.9 to 185 μg, according to MPPD and ExDoM2 estimates, respectively.

Health Impacts of Natural Background Radiation in High Air Pollution Area of Thailand.

Chiang Mai province of Thailand is known for having the highest natural background radiation in the country, as well as being recognized as one of the world's most polluted cities for air quality. This represents the major contributor to the development of lung cancer. This research aims to estimate the comprehensive dose of both internal and external exposure due to natural background radiation and related health perspectives in the highly polluted area of Chiang Mai. The average values of indoor radon and thoron concentrations in 99 houses over 6 months were 40.8 ± 22.6 and 17.8 ± 16.3 Bq/m3, respectively. These results exceed the worldwide value for indoor radon and thoron (40 and 10 Bq/m3), respectively. During burning season, the average values of indoor radon (56.7 ± 20 Bq/m3) and thoron (20.8 ± 20.4 Bq/m3) concentrations were higher than the world-wide averages. The radon concentration in drinking water (56 samples) varied from 0.1 to 91.9 Bq/L, with an average value of 9.1 ± 22.8 Bq/L. Most of the drinking water samples (87%) fell below the recommended maximum contamination limit of 11.1 Bq/L. The average values of natural radionuclide (226Ra, 232Th and 40K) in 48 soil samples were 47 ± 20.9, 77.9 ± 29.7 and 700.1 ± 233 Bq/kg, respectively. All values were higher than the worldwide average of 35, 30 and 400 Bq/kg, respectively. The average value of outdoor absorbed gamma dose rate (98 ± 32.5 nGy/h) exceeded the worldwide average of 59 nGy/h. Meanwhile, the average activity concentrations of 226Ra, 232Th and 40K in 25 plant food samples were 2.7 ± 0.1, 3.2 ± 1.6 and 1000.7 ± 1.9 Bq/kg, respectively. The 40K concentration was the most predominant in plant foods. The highest concentrations of 226Ra, 232Th and 40K were found in Chinese cabbage, celery and cilantro, respectively. The total annual effective dose for residents in the study area varied from 0.6 to 4.3 mSv, with an average value of 1.4 mSv. This indicates a significant long-term public health hazard due to natural background radiation and suggests a heightened radiation risk for the residents. The excess lifetime cancer risk value (5.4) associated with natural background radiation was found to be higher than the recommended value. Moreover, the number of lung cancer cases per year per million average of 25.2 per million persons per year was in the limit range 170-230 per million people. Overall, our results will be used for future decision making in the prevention of lung cancer risk associated with natural background radiation.

Po-210 in plankton and fish from coastal waters (gulf of Trieste, northern Adriatic Sea)

The activity concentrations of Po-210 were determined in seawater (<0.45 μm), suspended particulate matter (0.45–20 μm), fractionated plankton (20–50 μm, 50–200 μm, >200 μm) and tissues from four fish species, namely European seabass (Dicentrarchus labrax), Golden grey mullet (Chelon auratus), Gilt-head bream (Sparus aurata) and Common pandora (Pagellus erythrinus), collected in the Gulf of Trieste (northern Adriatic Sea). The activity concentration of Po-210 in seawater varied from 0.4 to 2.2 mBq/L in the dissolved phase (<0.45 μm) and from 0.4 to 0.8 Bq/L in suspended particulate matter (0.45–20 μm). Plankton fractionation showed the levels of 62–395 Bq/kg Po-210 in the >200 μm mesoplankton fraction, 65–459 Bq/kg in 50–200 μm and 52–537 Bq/kg in 20–50 μm microplankton fractions. No significant differences were found between fractions. The Po-210 distribution trend in fish tissues was in order: liver > stomach with intestine > kidney > spleen > gonads > gills > muscle. Bioaccumulation factors were determined for fish tissues indicating that the amount of Po-210 mostly depends on fish feeding habits. Hence, the main pathway entry of Po-210 is through ingested food. The highest estimated average total annual effective ingestion doses of Po-210 are obtained via the consumption of Common Pandora (7.1 μSv/year to 16.5 μSv/year) while the lowest doses are due to the consumption of European seabass (0.32 μSv/year to 0.76 μSv/year). Comparison with levels reported for other Mediterranean and Atlantic areas showed that only activitiy concentrations of Po-210 in fish appear significantly different, most likely because different fish species were analysed. The human dose exposure via fish consumption in the area is rather low.

Biomarkers of occupational benzene exposure: A Systematic Review to estimate the exposure levels and individual susceptibility at low doses.

Benzene is associated with diverse occupational and public health hazards. It exhibits an ability to rapidlypermeate the skin and contaminate water and food sources, leading to dermal and ingestion exposures. Despite numerous studies examining the associations between benzene and various indicators of harm, the findings have yielded inconsistent results. Furthermore, relying solely on air concentration as a measure of benzene exposure is limited, as it fails to account for internal exposure dose and individual susceptibility. This study aimed to conduct a comprehensive review in order to present current knowledge on benzene biomarkers and their significance in evaluating exposure levels and associated health hazards. The search methodology adhered to the PRISMA guidelines and involved the application of specific inclusion and exclusion criteria across multiple databases including PubMed, Embase, and Web of Science. Two researchers independently extracted and evaluated the relevant data based on predetermined criteria. Following the screening process, a total of 80 articles were considered eligible out of the initially retrieved 1053 articles after undergoing screening and assessment for inclusion. As the level of exposure decreased, specific biomarkers demonstrated a gradual increase in limitations, including heightened background concentrations and vulnerability to confounding factors. The advancement of sampling and analysis techniques will yield new biomarkers. Additionally, when conducting practical work, it is crucial to employ a comprehensive utilization of diverse biomarkers while excluding individual metabolic variations and combined exposure factors.

Association of sustained lupus low disease activity state with improved outcomes in systemic lupus erythematosus: a multinational prospective cohort study

Validation of protective associations of the lupus low disease activity state (LLDAS) against flare, irreversible damage, health-related quality of life, and mortality has enabled the adoption of treat-to-target strategies in patients with systemic lupus erythematosus (SLE). Previous validation studies were of short duration, limiting the ability to detect longer term signals in flare rate and irreversible damage. In addition, previous studies have focused on percent time at target, rather than actual periods of time that are more useful in clinical practice and trials. We assessed long-term protective associations of LLDAS and remission, and specifically examined protective thresholds of sustained LLDAS and remission. Patients aged 18 years or older with SLE were followed up from May 1, 2013, to Dec 31, 2020 in a prospective, multinational, longitudinal cohort study. Patients were recruited from 25 centres in 12 countries. Multi-failure time-to-event analyses were used to assess the effect of sustained LLDAS on irreversible damage accrual (primary outcome; measured with the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index) and flare (key secondary outcome; measured with the SELENA Flare Index), with dose exposure and threshold effects studied. Sustained LLDAS or remission were defined as two or more consecutive visits over at least 3 months in the respective state. This study is registered with ClinicalTrials.gov, NCT03138941. 3449 patients were followed up for a median of 2·8 years (IQR 1·1-5·6), totalling 37 662 visits. 3180 (92·2%) patients were women, and 3031 (87·9%) were of Asian ethnicity. 2506 (72·7%) patients had sustained LLDAS at least once. Any duration of sustained LLDAS or remission longer than 3 months was associated with reduced damage accrual (LLDAS: hazard ratio 0·60 [95% CI 0·51-0·71], p<0·0001; remission: 0·66 [0·57-0·76], p<0·0001) and flare (LLDAS: 0·56 [0·51-0·63], p<0·0001; remission: 0·66 [0·60-0·73], p<0·0001), and increasing durations of sustained LLDAS corresponded to increased protective associations. Sustained DORIS remission or steroid-free remission were less attainable than LLDAS. We observed significant protective associations of LLDAS and remission against damage accrual and flare, establish a threshold of 3 months sustained LLDAS or remission as protective, and demonstrate deepening protection with longer durations of sustained LLDAS or remission. The Asia Pacific Lupus Collaboration receives project support grants from AstraZeneca, Bristol Myers Squibb, EMD Sereno, GSK, Janssen, Eli Lilly, and UCB.

Effect of acute exposure of Hg on physiological parameters and transcriptome expression in silkworms (Bombyx mori).

Mercury (Hg) contamination poses a global threat to the environment, given its elevated ecotoxicity. Herein, we employed the lepidopteran model insect, silkworm (Bombyx mori), to systematically investigate the toxic effects of Hg-stress across its growth and development, histomorphology, antioxidant enzyme activities, and transcriptome responses. High doses of Hg exposure induced evident poisoning symptoms, markedly impeding the growth of silkworm larvae and escalating mortality in a dose-dependent manner. Under Hg exposure, the histomorphology of both the midgut and fat body exhibited impairments. Carboxylesterase (CarE) activity was increased in both midgut and fat body tissues responding to Hg treatment. Conversely, glutathione S-transferase (GST) levels increased in the fat body but decreased in the midgut. The transcriptomic analysis revealed that the response induced by Hg stress involved multiple metabolism processes. Significantly differently expressed genes (DEGs) exhibited strong associations with oxidative phosphorylation, nutrient metabolisms, insect hormone biosynthesis, lysosome, ribosome biogenesis in eukaryotes, and ribosome pathways in the midgut or the fat body. The findings implied that exposure to Hg might induce the oxidative stress response, attempting to compensate for impaired metabolism. Concurrently, disruptions in nutrient metabolism and insect hormone activity might hinder growth and development, leading to immune dysfunction in silkworms. These insights significantly advance our theoretical understanding of the potential mechanisms underlying Hg toxicity in invertebrate organisms.

Hormesis in Pathogenic and Biocontrol Fungi: From Inhibition to Stimulation

Hormesis, a biphasic response where low doses of stressors stimulate growth and high doses inhibit it, has significant implications for agricultural chemical use. This review explores the impact of low-dose fungicides or pesticides on pathogenic and biocontrol fungi. This study highlights how sublethal dose exposure can enhance growth and virulence of fungal pathogens, while also potentially increasing their stress tolerance at higher doses. This phenomenon complicates fungicide resistance management strategies. The review focuses on specific fungicides such as dimethachlone, prochloraz, carbendazim, and others, and their hormetic effects on fungal pathogens. Furthermore, the effects of low-dose pesticides and fungicides on beneficial fungi like entomopathogenic and arbuscular mycorrhizal fungi (AMF) are discussed. Here, low-dose exposure can stimulate the germination of entomopathogenic fungal conidia and enhance AMF root colonization and phosphorus uptake. However, hormesis can have trade-offs, potentially leading to unforeseen consequences for the organism. A thorough understanding of hormesis and dose-dependent fungicide effects is crucial for optimizing disease management and agricultural practices. This knowledge can inform strategies to minimize pathogen resistance and promote sustainable approaches. Implementing integrated disease management that combines fungicides with different modes of action alongside other control methods can be effective. Careful consideration of fungicide doses and potential hormesis effects is paramount for ensuring sustainable plant disease control and food security.

Effects of Different Doses of sUV-B Exposure on Taxane Compounds' Metabolism in Taxus wallichiana var. Mairei.

UV-B is an important environmental factor that differentially affects plant growth and secondary metabolites. The effects of supplemental ultraviolet-B (sUV-B) exposure (T1, 1.40 kJ·m-2·day-1; T2, 2.81 kJ·m-2·day-1; and T3, 5.62 kJ·m-2·day-1) on the growth biomass, physiological characteristics, and secondary metabolites were studied. Our results indicated that leaf thickness was significantly (p < 0.05) reduced under T3 relative to the control (natural light exposure, CK); The contents of 6-BA and IAA were significantly reduced (p < 0.05); and the contents of ABA, 10-deacetylbaccatin III, and baccatin III were significantly (p < 0.05) increased under T1 and T2. The paclitaxel content was the highest (0.036 ± 0.0018 mg·g-1) under T3. The cephalomannine content was significantly increased under T1. Hmgr gene expression was upregulated under T1 and T3. The gene expressions of Bapt and Dbtnbt were significantly (p < 0.05) upregulated under sUV-B exposure, and the gene expressions of CoA, Ts, and Dbat were significantly (p < 0.05) downregulated. A correlation analysis showed that the 6-BA content had a significantly (p < 0.05) positive correlation with Dbat gene expression. The IAA content had a significantly (p < 0.05) positive correlation with the gene expression of Hmgr, CoA, Ts, and Dbtnbt. The ABA content had a significantly (p < 0.05) positive correlation with Bapt gene expression. Dbat gene expression had a significantly (p < 0.05) positive correlation with the 10-deacetylbaccatin content. Hmgr gene expression was positively correlated with the contents of baccatin III and cephalomannine. Bapt gene expression had a significantly (p < 0.01) positive correlation with the paclitaxel content. A factor analysis showed that the accumulation of paclitaxel content was promoted under T2, which was helpful in clarifying the accumulation of taxane compounds after sUV-B exposure.