Exposure Dose Research Articles

A multimodal in vitro approach to assess the safety of oral care products using 2D and 3D cellular models.

Periodontitis, affecting approximately 3.9 billion individuals globally, significantly impacts quality of life and has raised interest in its potential systemic effects. Sodium perborate, a common component in oral care products for biofilm control, is widely used, though concerns about its safety persist. This study aimed to evaluate the in vitro toxicity of six commercial oral care products and varying concentrations of sodium perborate, utilizing human gingival fibroblasts (HGF) and keratinocytes (HaCat) as cell models. Experiments were performed in both 2D monolayer and 3D cultures using MTT and electrical impedance assays, adhering to the manufacturer's recommended exposure time of 30-60s for product testing. For the reconstructed epidermis model, a prolonged exposure time of 42min was applied, following the Organization for Economic Cooperation and Development (OECD) Test Guideline 439. Results indicated that all products and sodium perborate at 1mg/mL were cytotoxic in monolayer cultures. However, at concentrations relevant to commercial formulations (0.06mg/mL sodium perborate), no significant toxicity was observed. In contrast, the 3D culture models, including spheroids and reconstructed epidermis, exhibited minimal to no cytotoxic effects for the commercial products, with sodium perborate showing no significant toxicity below 0.1mg/mL. The reconstructed epidermis model, used as surrogate for oral mucosa, further confirmed that the products were non-irritating, in compliance with OECD TG 439 standards. This study highlights the importance of considering exposure time, dosage, and cellular model when assessing the safety of oral care products. While 2D models are useful for preliminary screenings, 3D models provide a more physiologically relevant assessment, emphasizing the need for robust testing protocols to ensure product safety.

Air Plasma Jet Generation Apparatus "ALOE" A.V. Kazak, L.V. Simonchik

The article presents an apparatus for generating an air plasma jet "ALOE". The device differs from known analogues in its compactness achieved due to absence of need to use inert gases (because they are replaced by ambient air) and the ability to determine the exposure dose. In terms of its characteristics this new product corresponds to world standards. There are no domestic analogues of it. Parameters and examples of using this device are presented. It will be in demand for healthcare, veterinary medicine, and cosmetology. The device can be used for disinfection of surfaces, including heat-sensitive ones, such as living tissues, and can serve as a prototype for development of various physiotherapeutic devices.

EFFECTIVE DOSE ANALYSIS IN ABDOMEN AP EXAMINATION PATIENTS WITH CALDOSE_X VERSION 5.0

This study evaluates radiation dose exposure during diagnostic radiology procedures using X-rays and their potential risks, including cancer, to optimize radiation safety through the CALDose_X software that calculates the absorbed organ dose, effective dose, and cancer risk, according to the lowest possible achievable (ALARA) principle. This study used a quantitative experimental design to evaluate the impact of filter thickness variations on Entrance Surface Air Kerma (ESAK) and effective dose by analyzing data from 54 patients undergoing AP Abdominal X-ray examinations. The results showed that the effective dose to the abdominal organs varied with exposure factors and Focus to Detector Distance (FDD), where the colon wall had the highest sensitivity with doses ranging from 0.030 mSv to 0.126 mSv, followed by the stomach and pancreas. Increasing kV, mAs, and FDD increased the effective dose, emphasizing the importance of careful dose management. This study concluded that exposure factors and FDD affect the effective dose received by the abdominal organs, with recommendations to monitor patient doses, revise national diagnostic reference levels, and establish standard protocols with health authorities. Keywords: CALDose_X, X-ray Exposure Factor, patient dose, ESAK, Effective Dose, Abdomen AP.

CBCT-based online adaptive radiotherapy of the prostate bed: first clinical experience and comparison to nonadaptive conventional IGRT.

Conventional image-guided radiotherapy (IGRT) of the prostate bed is challenged by the varying anatomy due to dynamic changes of surrounding organs such as the bladder and rectum. This leads to changed dose coverage of target and surrounding tissue. The novel online adaptive radiotherapy (oART) aims to improve target coverage as well as reduce dose exposure to surrounding healthy tissues by daily reoptimization of treatment plans. Here we set out to quantify the resulting changes of this adaptation for patients and treatment team. Atotal of 198 fractions of radiotherapy of the prostate bed (6patients) were treated using oART with the Ethos accelerator (Varian Medical Systems, Palo Alto, CA, USA). For each fraction, volumes and several dose-volume parameters of target volumes and organs at risk were recorded for the scheduled plan (initial plan, recalculated based on daily cone beam computed tomography [CBCT]), the adapted plan, and the verification plan, which is the dose distribution of the applied plan recalculated on the closing CBCT after the adaptation process. Clinical acceptability for all plans was determined using given dose-volume parameters of target volumes. Additionally, the time needed for the adaptation process was registered and compared to the time required for the daily treatment of five conventional IGRT patients. Volumes of target and organs at risk (OAR) exhibited broad variation from day to day. The differences in dose coverage D98% of the clinical target volume (CTV) were significant through adaptation (p < 0.0001; median D98% 97.1-98.0%) and further after verification CBCT (p < 0.001; median D98% 98.1%). Similarly, differences in D98% of the planning target volume (PTV) were significant with adaptation (p < 0.0001; median D98% 91.8-96.5%) and after verification CBCT (p < 0.001; median D98% 96.4%) with decreasing interquartile ranges (IQR). Dose to OAR varied extensively and did not show aconsistent benefit from oART but decreased in IQR. Clinical acceptability increased significantly from 19.2% for scheduled plans to 76.8% for adapted plans and decreased to 70.7% for verification plans. The scheduled plan was never chosen for treatment. The median time needed for oART was 25 min compared to 8 min for IGRT. Target dose coverage was significantly improved using oART. IQR decreased for target coverage as well as OAR doses indicating higher repeatability of dose delivery using oART. Differences in doses after verification CBCT for targets as well as OAR were significant compared to adapted plans but did not offset the overall dosimetric gain of oART. The median time required is three times higher for oART compared to IGRT.

Increasing coil temperature of a third-generation e-cigarette device modulates C57BL/6 mouse lung immune cell composition and cytokine milieu independently of aerosol dose

ABSTRACT Higher coil temperature in e-cigarette devices increases the formation of aerosols and toxicants, such as carbonyls. At present, the health implications of vaping at higher temperatures, including exacerbation of pulmonary inflammation, are largely unknown when aerosol dose is considered. To isolate the pulmonary effects of coil temperature, C57BL/6 mice were exposed to e-cigarette aerosols generated at lower (190°C) or higher (250°C) temperature for 3 days, while maintaining a similar chamber aerosol concentration. Increasing coil temperature did not markedly alter aerosol mass-normalized emissions of select carbonyls formed from thermal degradation pathways including formaldehyde, acetaldehyde, propionaldehyde, and acetone under the tested environment. Total bronchoalveolar cells, primarily macrophages, were significantly decreased in mice exposed to aerosols generated with higher coil temperatures compared to lower temperature exposures. The gene expression of IFNβ, IL-1β, TNFα, and IL-10 in mouse lung tissue was significantly reduced following e-cigarette exposure under both conditions, compared to filtered air exposure. Higher temperature exposures further exacerbated downregulation of IFNβ and IL-1β. Data suggest that higher temperature vaping might modulate acute pulmonary immune responses, potentially inducing immune suppression, even when normalized for aerosol dose exposure. Coil temperature thus appears to be an important parameter that needs to be regulated to ensure harm reduction for e-cigarette users.

Quantitative evaluation of residual resist in electron beam lithography based on scanning electron microscopy imaging and thresholding segmentation algorithm

Electron beam lithography is a critical technology for achieving high-precision nanoscale patterning. The presence of resist residues in the structures can significantly affect subsequent processes such as etching and lift-off. However, the evaluation and optimization of resist residues currently relies on qualitative observations like scanning electron microscopy (SEM), necessitating multiple experiments to iteratively optimize exposure parameters, which is not only labor-intensive but also costly. Here, we propose a quantitative method to evaluate resist residues. By processing the obtained SEM images using a threshold segmentation algorithm, we segmented the resist structure region and the residual resist region in the images. The grayscale values of these two regions are identified, and the residues are quantified based on the ratio of these values. Furthermore, a relationship curve between the residue amount and the exposure dose is plotted to predict the optimal exposure dose. To validate this method, we fabricated hydrogen silsesquioxane annular grating structures with 30 nm linewidth and analyzed the residue levels over an exposure dose range of 2000-2500μC cm-2, predicting the optimal dose to be 1800μC cm-2and confirming this through experiments. Additionally, we applied the method to polymethyl methacrylate and ZEP-520A structures, achieving similarly accurate results, further confirming the method's general applicability. This method has the potential to reduce experimental costs and improve yield and production efficiency in nano fabrication.

Toxicological effects and potential reproductive risk of microplastic-induced molecular changes in protamine-like proteins and their DNA binding

Today, plastic pollution is a widespread problem in all ecosystems and has a particularly severe impact on marine ecosystems and external fertilisers such as the mussel Mytilus galloprovincialis. The present study aims to assess the toxicological reproductive health effects in this organism following exposure to two concentrations of polystyrene microplastics (PS-MPs) (0.5 and 1 μg/L), representative of conditions in the Mediterranean Sea. After exposure, the electrophoretic pattern of protamine-like (PL) proteins, the major basic protein component of Mytilus galloprovincialis sperm chromatin, was analysed. Compared to the unexposed condition, differences were observed by SDS-PAGE and an increased ability of PL to bind and protect DNA from oxidative damage was then measured, particularly for PL from mussels exposed to 1 μg/L PS-MPs. At this dose of PS-MPs, a reduced release of all PLs from the sperm nuclei was also observed, whereas the digestion by micrococcal nuclease did not show any significant differences between the exposed and the unexposed conditions. Finally, the possibility of poly(ADP)-ribosylation of the PLs was investigated. PL-II showed an increase in poly(ADP)-ribosylation after PS-MPs exposure, which may account for the difference in the ability of the PLs to bind DNA. In conclusion, while all the results might suggest a molecular mechanism of gametic plasticity occurring upon exposure of mussels to PS-MPs 1 μg/L, they also indicate that this dose of exposure could be extremely detrimental to the reproductive health of Mytilus galloprovincialis because it could prevent the release of basic nuclear proteins from the sperm DNA at fertilisation.

Congenital and Fetal Effects After Mifepristone Exposure and Continuation of Pregnancy: A Systematic Review.

Mifepristone is an anti-progestational drug that is the first component of the standard medical abortion regimen. For women who take mifepristone and then do not take misoprostol, which is the second component of the medical abortion regimen, it is possible that their pregnancy may continue to live birth. Since mifepristone is commonly used for medical abortion up to 9-10 weeks gestation, any adverse or teratogenic effects on the developing embryo/fetus must be considered, given exposure during the critical time of its development and organogenesis. Toxicology and teratology reports have cited studies demonstrating teratogenic effect of mifepristone in some animals. Current clinical guidelines for women exposed to mifepristone in the first trimester of pregnancy state that it is not known to be teratogenic based on limited published evidence from humans. The aim of this narrative systematic review was to investigate embryonic/fetal exposure to mifepristone and any association with congenital or fetal anomalies. This study was conducted by systematic searches of health databases from inception to February 2024. The references of relevant citations were manually searched to retrieve any additional citations not captured in database searching. Congenital anomalies and adverse outcomes were encountered at various doses of mifepristone exposure. A number of the congenital anomalies encountered in this review were explained by circumstances other than exposure to mifepristone. The present systematic review did not find data to support mifepristone being implicated as a teratogen.

Exposure Matching-Based Pediatric Dose Selection for Drugs with Renal Excretion - Lessons Learned from Pediatric Development of Direct Oral Anticoagulants.

The pediatric clinical development programs of the direct oral anticoagulants (DOACs) edoxaban, rivaroxaban, and dabigatran have recently been completed, with apixaban close to the finish line. One common pharmacokinetic (PK) characteristic of these four DOACs is that renal excretion contributes 27% or more in their elimination, resulting in age-dependent drug clearance in both pediatric and adult subjects. Several lessons have been learned from adult exposure matching and pediatric dose selection for DOACs. The main goal of this tutorial is to provide an informed perspective on pediatric dose selection for renally excreted drugs, using these four DOACs as case examples. This tutorial is organized into seven steps: (1) consideration of age-related differences in disease and response to treatment; (2) consideration of age-related differences in drug absorption, distribution, metabolism, and excretion; (3) selection of the reference adult population and exposure for pediatric exposure matching; (4) prediction of pediatric clearance and pediatric dose selection based on data from young adults; (5) conduct and design of efficient pediatric PK and pharmacodynamic (PD) studies that inform dose selection; (6) assessment of exposure matching and dose adjustment using population PK simulation; (7) evaluation of the need for dose adjustment in pediatric sub-populations.

Identification of Albopleistophora grylli n. gen. n. sp. (Microsporidia) and its impact on crickets (Gryllus spp.) in food-and-feed culture systems

This study provides a comprehensive taxonomic description of a microsporidian parasite infecting crickets, Gryllus bimaculatus and G. assimilis. Our analysis includes gross pathology, histopathology, spore ultrastructure, parasite development cycle, single gene phylogenies, and phylogenomic comparisons. We introduce a new taxon, Albopleistophora grylli n. gen. n. sp., characterised by its unique developmental stages within a sporophorous vesicle, leading to the formation of mature spores measuring 5.7 × 2.8 µm. Although prevalent in commercial cricket cultures, this parasite seemed to have limited effects on cricket survival. Indeed, microsporidia exposure and density assays with the host G. bimaculatus, only revealed density as a significant factor affecting the crickets’ survival. Nevertheless, exposure showed significant effect on the crickets’ emergence time, where exposed crickets emerged as adults earlier than unexposed individuals. Moreover, exposure to the parasite increased the faeces production and weight gain in cricket males. However, neither exposure nor density significantly impacted the females’ fecundity. The absence of spores in non-exposed cricket groups suggested a horizontal transmission, highlighting the importance of controlled rearing practices to eliminate this microsporidium in control groups. The well-known anti-microsporidian drug ‘fumagillin’ was studied with a higher microsporidia dose of exposure to evaluate any improvement in cricket survival, without showing any significant differences between exposed and unexposed groups. Our findings underscore the nuanced dynamics of host-microsporidia interactions and emphasise the need for ecological context in understanding microsporidian impacts. Even if non-dangerous for its host, monitoring of this parasite seems crucial due to its potential zoonotic transmission by its close phylogenomic relation to human-infecting microsporidia species.

Terahertz refractive index control of 3D printing materials by UV exposure

Recently, significant progress has been made in the development of THz optics based on metamaterials to overcome the limited availability of suitable materials for conventional optics. Although 3D printing technology is a promising method for rapidly fabricating these subwavelength structures, the structural degree of freedom for 3D printed metamaterials is still limited by the optical properties of printing materials. In this study, we controlled the THz refractive index and extinction coefficient of the 3D printing resin by UV exposure doses during the printing process. Samples were fabricated as uniform plates under different curing conditions in printing, and their optical properties were measured in the range between 0.3 THz and 2.0 THz using THz time-domain spectroscopy (THz-TDS). The refractive index and extinction coefficient were changed from 1.65 to 1.80, and from 0.04 to 0.12, respectively, with increasing UV doses from 1 mJ/cm2, which allows resin to solidify and become printable, to 100 mJ/cm2, where the optical changes become almost saturated. The results provide insights into optimizing the fabrication process of THz devices, even those with a gradient and complex refractive index profile, by utilizing 3D printing technology for a broad range of applications.

The effect of photo-thermo-induced crystallization on the properties and microstructure of transmission volume Bragg gratings

Volume Bragg gratings (VBGs) recored on photo-thermo-refractive (PTR) glass are extensively utilized in high power lasers, optical communication, holographic display fields, etc. In the majority of application fields, high refractive index modulation (RIM) value and high transmittance are the required parameters for transmission Volume Bragg gratings (TVBGs) devices. This study indicates that the RIM values and transmittance of TVBGs strongly depend on the size and concentration of sodium fluoride (NaF) crystals within the grating periodic structure. Increasing the UV exposure dose causes a reduction in the size of NaF crystals, leading to a finitely rise in the RIM value of TVBGs. Prolonging the crystallization heat treatment time and elevating the temperature effectively enhance the RIM value of TVBGs, which also significantly enlarge the size of NaF crystals in the grating periodic structure. By fine-tuning the process parameters of photothermal induced crystallization, a RIM value of 20–320 ppm is freely controlled. For 1.5 mm thick TVBGs, the above RIM value range can meet the application requirements of achieving high diffraction efficiency in the visible to near-infrared range. Following UV exposure at a dose of 5 J/cm2 and nucleation at 480 °C for 120 min, crystallization treatments at 550 °C for 30–60 min and at 570 °C for 60–120 min are determined as optimal for fabricating TVBGs with high diffraction efficiency and transmittance in the visible (532 nm) and near-infrared (1053 nm) bands, respectively.

Solar ultraviolet radiation exposure of trail runners in an ultraendurance competition at high altitude

BackgroundOutdoor sports are associated with overexposure to solar ultraviolet radiation and sunburn. AimsTo quantify solar ultraviolet radiation (UVR) exposure received by trail runners during an ultraendurance competition at high altitude and to assess their sun exposure habits, sun protection behaviors, and attitudes and knowledge regarding skin cancer. MethodsTrail runners taking part in the 2023 Ultra Sierra Nevada race (Spain, April 14–16, 2023) completed an online validated questionnaire on sun-related habits, behaviors, attitudes, and knowledge. Environmental conditions such as temperature, relative humidity, and UVR as well as participants’ personal erythemal dose were measured during the competition. ResultsThe average ambient cumulative erythemal dose ranged from 59.9 to 19.3 standard erythemal doses (SED) and the mean effective radiation received by the athletes studied (n = 17) ranged from 24.2 to 7.6 SED in the Extreme (154 km) to Half-Marathon (25.1 km) races. The questionnaire was completed by 194 athletes (mean age 41.3 ± 8.9 years; 76.8 % men). A total of 22.4 % of athletes surveyed reported skin phototype I-II. Two-thirds (66.5 %) had sunburn after doing outdoor sports in the previous year. In regard to photoprotection practices while exercising outdoors, 62.6 % reported wearing a hat/cap, 59.2 % avoided the midday sun, 38.7 % used sunscreen with sun protection factor ≥ 15, and 49.7 % stated they did not reapply sunscreen. ConclusionsThe trail runners studied received a high solar exposure dose during the competition. Future interventions are needed to improve individual and organizational photoprotection measures in trail-running events to reduce the risk of skin cancer.

Distribution of Bisphenol A Diglycidyl Ether (BADGE) and Its Derivatives in Indoor Dust from Various Micro-environments in Hanoi, Vietnam

In this report, the method for the determination of BADGE and its derivatives in dust samples has been optimized. The recoveries of the surrogate standard (d6-BADGE) and target compounds (in matrix spiked) were in the ranges of 78.5–99.0% and 75.4–116% (SD &lt; 10.0), respectively. Total concentrations of BADGEs in indoor dust ranged from no detection (ND) to 6640 ng/g (mean: 950 ng/g and median: 434 ng/g). The mean (median) concentrations of four BADGEs in indoor dust samples collected from public places, homes, laboratories, and offices were 1630 (830), 957 (434), 707 (375), and 344 (170) ng/g, respectively. Among BADGEs, BADGE.2H2O was found at the highest levels with the ranges of ND–4880 ng/g (mean: 634, and median: 247) in indoor dust from all micro-environments. A significant correlation existed between the sum concentrations of two pairs: BADGE + BADGE.H2O and BADGE.2H2O + BADGE.HCl.H2O. Based on the measured concentration of BADGEs in indoor dust, the estimated exposure doses to BADGEs through dust ingestion were respectively in ranges of 0.406-1.92 and 0.351–1.66 ng/kg-bw/d for women and men.

Single‐Component High‐Resolution Dual‐Tone EUV Photoresists Based on Precision Self‐Immolative Polymers

AbstractElectron beam (EB) and extreme ultraviolet (EUV) lithography are advanced techniques capable of achieving sub‐10 nm resolutions, critical for fabricating next‐generation nanostructures and semiconductor devices. However, developing EUV photoresists that meet all demands for resolution, line edge roughness (LER), and sensitivity (RLS) remains a significant challenge. Herein, we introduce high‐performance photoresists based on single‐component self‐immolative polymers (SIPs) with inherent signal amplification via cascade degradation. These SIPs function as dual‐tone photoresists under both EB and EUV lithography, with performance primarily determined by the exposure dose. Lithographic evaluations show that discrete SIPs provide significant improvements over disperse counterparts, achieving higher resolution and reduced LER. Specifically, a discrete SIP with a DP of 12 produces a line‐space pattern with a resolution of approximately 18 nm and an LER of 1.8 nm, compared to 21 nm resolution and 2.5 nm LER for disperse SIPs. Additionally, these SIP‐based photoresists, enriched with aromatic structures, exhibit excellent etch resistance. The single‐component nature and potential to address the RLS trade‐off underscore the promise of discrete SIPs for EUV lithography.

Radiation Exposure to the Brains of Interventional Radiology Staff: A Phantom Study.

Numerous papers report the occurrence of head and neck tumors in interventional radiology (IR) physicians. Recently, appropriate dosimetry and protection have become much more important. To accomplish these, first, we should accurately understand how the brain is exposed. We assessed the dose distribution of the head and clarified the relationship between head exposure and brain dose. We used eight radiophotoluminescence dosimeters (RPLDs), two at the surface of the eyes and six inside the phantom head. We conducted measurements with three kinds of irradiation fields: one irradiated the whole head, the second irradiated the brain region, and the third irradiated the soft tissue of the face. The cranial bone reduced the brain dose to less than half the skin dose: about 48% at the front and less than 9% at the back of the brain. Due to the brain exposure, the soft tissues were slightly exposed to the scatter radiation from the cranial bone. We revealed the dose distribution of the head and the influence of the scatter radiation from the cranial bone and the soft tissues of the face. There are two kinds of scatter radiation: from the cranial bone to the soft tissue of the face, and from the soft tissue to the brain. Although the influence of these sources of scatter radiation is not significant, the relationship between brain exposure and the occurrence of head and neck tumors is still unclear. Therefore, some IR physicians should keep this in mind if they receive high levels of exposure in their daily practice.

Including highly educated migrants in academia to improve their health-protocol for a pilot intervention.

Norway's healthcare system needs a diversified work force to meet societal demands for improved cultural competence. However, many migrants in Norway who were educated as health professions in their home countries are not practicing these professions. This may negatively affect their physical and mental health and hinder their personal social integration. Though good health is often seen as a precondition for work, relevant working activities can also improve health. However, including health professionals with foreign education in academic institutions prior to receiving necessary accreditation is a complex task. This study will pilot an intervention aiming to improve health through meaningful integration of these professionals in academic environments. This paper is a protocol for a non-randomized pilot intervention study targeting migrants who are waiting for their health education accreditation in Norway. To test the benefits of meaningful activity on health and explore possibilities for implementing such activity, we have designed a six-month long intervention consisting of including nurses, doctors, and other highly educated migrants with healthcare backgrounds between 20 and 67 years of age, into health-related working tasks, at two higher education institutions in Bergen, Norway. The intervention will be tailored according to the participant's expertise. This hybrid type 2 pilot protocol paper will present how feasibility, fidelity, dose received (satisfaction), and dose of exposure (participation), will be assessed and whether the intervention is experienced as beneficial for the participants' health as primary outcome utilizing both quantitative and qualitative methods. We present a complex, personalized intervention that has the potential for large scale implementation in the future. By thoroughly presenting our designed intervention and assessment methods, this protocol will add to the study's transparency and facilitate replicability and comparison with future studies. This study will be of benefit to the migrants themselves, policy makers, government agencies and academia at large as it can point to a unique and sustainable way of speeding up the integration of highly educated migrants in their respective fields in a new host country.

Evaluation of hand-arm vibration (HAV)exposure among groundskeepers in the southeastern United States.

The objectives of this study were to evaluate daily hand-arm vibration (HAV)exposure among groundskeepers, characterize power tools used, and estimate lifetime cumulative HAV exposure dose. Seventeen groundskeepers and ten office workers employed at two US southeasterrn institutions were recruited as a target exposure group and a reference group, respectively. A 6-dexposure assessment of HAV was scheduled, and vibration dosimeters were used to obtain daily vibration exposure value, A(8). Information on power tools used and corresponding operation duration was recorded to assign the real-time vibration data collected from the dosimeters for tool characterization in terms of vibration total value (ahv) and frequency. Lifetime cumulative exposure dose, ahv-lifetime, was determined using ahv for all tools used and lifetime exposure duration obtained through a questionnaire. The individual groundskeepers' average A(8) ranged from0.8 to 2.6 and from1.0 to 2.6 m/s2 for the right hand and left hands, respectively. Among 11 power tools used by the groundskeepers, grass trimmers contributed the most to the vibration exposure. The average ahv of the individual tools ranged from 8.0 (chainsaws) to 1.9 m/s2 (seating mowers and handheld blowers) for the right hand and from 6.4 (push mowers) to 1.4 m/s2 (backpack blowers) for the left hand. The highest acceleration peak of grass trimmers, edgers, backpack blowers, pole saws, riding blowers, and hedgers was observed between 100 and 200 Hz while riding mowers, seating mowers, push mowers, and chainsaws showed the highest acceleration peak at lower frequencies (≤63.5 Hz). The groundskeepers' average ahv-lifetime was 76,520.6 and 61,955.5 h m/s2 for the right and left hands, respectively. The average ahv-lifetime of office workers was 2,306.2 and 2,205.8 h m/s2 for the right and left hands, respectively, which was attributed to personal hobby activities. Three groundskeepers' average A(8) reached 2.5 m/s2, the Action Limit recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). The highest contribution to the vibration exposure was observed during grass trimmer operations with a major acceleration peak at 100 Hz. The groundskeepers' ahv-lifetime was 33 and 28 times higher for the right and left hands, respectively, than the office workers.

Usefulness of monitoring mycophenolic acid exposure in systemic sclerosis-related interstitial lung disease: a retrospective cohort study

BackgroundSystemic sclerosis-related interstitial lung disease (SSc-ILD) represents a significant cause of morbidity and mortality in Systemic Sclerosis (SSc). Mycophenolate mofetil (MMF) is currently the first line treatment for SSc-ILD. There is no recommendation on the dosage of mycophenolic acid (MPA) blood concentrations, so we aimed to study the correlation between MPA exposure and respiratory outcomes in this population.MethodsWe conducted a retrospective cohort study of SSc-ILD patients treated with MMF in our center. According to our policy, a complete patient evaluation was performed approximately one year after MMF initiation, during which the mycophenolic acid (MPA) residual rate (RR) was measured. We analyzed the association between RR and changes in forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLCO) over time.ResultsForty-three SSc-ILD patients were included. Patients with higher RR levels (≥ 1.5 mg/L) had a significantly better FVC evolution with a higher proportion of stabilization and lower proportion of FVC decrease (p = 0.024). RR above 1.5 mg/L was a predictive factor of reduced FVC decline compared with lower RR levels adjusting for MMF dose and duration of MMF exposure (p = 0.008). There was no difference regarding DLCO outcome.ConclusionOur study suggests that optimal MPA exposure, as indicated by RR levels, may better protect against FVC decline in SSc-ILD patients treated with MMF. Routine monitoring of MPA exposure could be beneficial in optimizing treatment outcomes. Prospective, multicenter studies are needed to further explore the relationship between MPA exposure and clinical outcomes in SSc-ILD.

Picking a bone with fluoride – dose-response meta-analysis on exposure to fluoride and bone density

Abstract There are still uncertainties around the effects, beneficial and adverse, of water fluoride exposure on bone density and strength. We selected bone mineral density (BMD) for investigation as it is recognized as the major non-invasive indicator of bone strength, representing its clinical assessment standard. The aim of this systematic review and meta-analysis was to characterize for the first time the relation between fluoride exposure and BMD through a dose-response approach, using a one-stage dose-response meta-analysis based on a cubic spline random-effects model. Out of 1201 potentially relevant literature records retrieved, after removing duplicates, title/abstract screening, and full-text evaluation, 16 studies were eligible for this review, 12 of which were also suitable for the dose-response meta-analysis. We observed an almost linear association between fluoride and BMD, yielding a mean difference of 2.60 (95% CI 0.17 to 0.40) at 4 mg/L of fluoride exposure. This pattern was also confirmed for hip BMD (MD = 2.83; 95% CI 0.11 to 0.40 at 4 mg/L). However, sex-specific analyses showed different patterns of association. In males, the relation between fluoride exposure and BMD was almost linear until 0.75 mg/L (MD = 0.24; 95% CI -0.22to 0.37), after which it plateaued. Females showed a slight increased BMD at 1 mg/L (MD = 0.05; 95% CI -0.02 to 0.16) but decreasing values above 2.5 mg/L (MD=-0.22; 95% CI -2.72 to 2.38 at 4 mg/L), with an indication of an inverted U-shaped association. This pattern was clearer when we restricted our analysis to hip BMD (MD=-0.56; 95% CI -2.98 to 1.85 at 4 mg/L). Sensitivity analyses examining both bone-specific BMD and conducting risk of bias assessments are currently underway. Moreover, imprecision of the estimates, especially in stratified analyses, and potential for residual confounding, underscore the need for further prospective studies, to more adequately assess the relation between fluoride exposure and bone density and strength. Key messages • At fluoride exposure below 1 mg/L, we observed a linear correlation between fluoride exposure and increase bone density in the overall pooled dose-response analysis of eligible studies. • Sex-specific patterns: males show positive response until certain exposure threshold; while females demonstrate an increase only at low doses of exposure and a downward trend at higher exposures.