Reference Level Research Articles

Diagnostic reference levels in spinal CT: Jordanian assessments and global benchmarks.

To reduce radiation dose and subsequent risks, several legislative documents in different countries describe the need for Diagnostic Reference Levels (DRLs). Spinal radiography is a common and high-dose examination. Therefore, the aim of this work was to establish the DRL for Computed Tomography (CT) examinations of the spine in healthcare institutions across Jordan. Data was retrieved from the picture archiving and communications system (PACS), which included the CT Dose Index (CTDI(vol)) and Dose Length Product (DLP). The median radiation dose values of the dosimetric indices were calculated for each site. DRL values were defined as the 75th percentile distribution of the median CTDI(vol) and DLP values. Data was collected from 659 CT examinations (316 cervical spine and 343 lumbar-sacral spine). Of the participants, 68% were males, and the patients' mean weight was 69.7 kg (minimum = 60; maximum = 80, SD = 8.9). The 75th percentile for the DLP of cervical and LS-spine CT scans in Jordan were 565.2 and 967.7 mGy.cm, respectively. This research demonstrates a wide range of variability in CTDI(vol) and DLP values for spinal CT examinations; these variations were associated with the acquisition protocol and highlight the need to optimize radiation dose in spinal CT examinations.

A study on the effects of vitamin D supplementation on hematological parameters and serum 25-hydroxy vitamin D in healthy dogs

BackgroundLimited studies are available on vitamin D supplementation in dogs. This study evaluates the effect of a commercial vitamin D3 supplement on serum 25-hydroxy vitamin D as well as selected biochemical and hematological parameters in healthy dogs. Eight intact male adult dogs with a mean body weight of 20 kg from mixed breeds were included in the study. After adaptation period, dogs received vitamin D3 supplement at the dose of 50 IU/kg body weight per day. Blood samples were collected on days 0, 14, 28 and 42 of supplementation. Food was used for analysis of vitamin D3 content.ResultsSignificant increase in serum level of 25-hydroxy vitamin D3 was detected since day 14 of supplementation. Changes in serum 25-hydroxy vitamin D3 concentration during time showed an upward significance (p < 0.05). Vitamin D3 content of the food was 2900 IU/kg dry matter. Changes in serum phosphorus levels were upward significant. No dog showed calcium or phosphorus levels above the highest reference level. Liver and kidney parameters remained in the reference range during the experiment. A gradual significant increase was observed in hemoglobin and hematocrit which was started from day 14. Vitamin D3 supplementation had no significant effect on neutrophils, monocytes and lymphocytes percent during the study.ConclusionsVitamin D3 supplementation at 50 IU/kg BW daily, increases serum levels of 25-hydroxy vitamin D in healthy dogs fed with a diet containing proper amount of this vitamin. It also increases hemoglobin and hematocrit levels in a time dependent manner without inducing adverse effects.

The impact of clinical audits on patient radiation exposure for device procedures

Abstract Background Clinical audits aim to ensure ideal use of ionizing radiation in clinical practice. Since it became mandatory by Swiss law in 2018, such an audit also took place in our Cardiac Pacing and Electrophysiology Division at the University Heart Center. Purpose To establish local diagnostic reference levels (DRLs) for specific procedures and to examine if patient radiation exposure was reduced after the clinical audit. Methods Retrospective cohort study including patients from October 2018 to October 2020 who underwent device implantation, including pacemakers, implantable cardioverter defibrillators (ICD), cardiac resynchronization therapy (CRT), or lead extraction / device explantation. Main measures to reduce radiation exposure after the audit were lower pulsed fluoroscopy frame rates and dose characteristics at baseline. Patient radiation exposure was evaluated with the dose-area product (DAP), cumulative dose, fluoroscopy time, and the number of cine acquisitions. Secondary endpoints included the effective dose, the acute procedural success rate and 30-day complications. Data were collected from a dose management system and cross-checked for accuracy with the patient information system. The third quartiles were set as local DRLs. Data before and after the clinical audit were compared. Results A total of 541 patients (45.7 % before the audit, 54.3% after the audit) were included. 28.3% had a conventional pacemaker, 22.0% a leadless pacemaker, 21.1% an ICD, and 17.2% a CRT implantation. Lead extraction / device explantation was undergone by 11.5% of patients. The local DRLs (including all procedures before and after the audit) for the DAP were significantly lower as compared to national DRLs (6.2 dGy.cm2 versus 300 dGy.cm2 for conventional pacemakers; 7.6 dGy.cm2 versus 200 dGy.cm2 for ICDs, 203 dGy.cm2 versus 570 dGy.cm2 for CRTs). After the audit, DAP (Figure 1), cumulative dose, effective dose and the number of cine acquisition significantly decreased for conventional pacemakers (p-value ≤ 0.04), whereas no significant differences were observed for the other procedures. The acute procedural success rate (98.4 vs 98.9%) and the 30-day complications (4.0 vs 7.8%) were not significantly different before and after the audit. Conclusions The clinical audit in our institution led to a significant reduction of radiation exposure for patients during pacemaker implantations. Regarding DRLs, local values were far below national DRLs, which suggests that national DRLs need to be updated more regularly. Our study highlights the importance of clinical audits and the need for more research in this field.

Initial experience with ablation of ventricular arrhythmias using a pulsed-field system

Abstract Introduction Catheter ablation using radiofrequency (RF) current is a well-established method of treatment of ventricular arrhythmias (VA). However, RF ablation may fail to eliminate deeply located arrhythmogenic substrate. Pulsed-field (PF) is a novel energy source with a potential to create deeper lesions, especially in scar tissue. Purpose This study aims to present the data on safety and efficacy (acute outcome data) of VA ablation using PF. Methods The population consists of 15patients (5 women, age: 61 ± 19years) after previously failed RF ablation of VA. The underlying condition was nonischemic cardiomyopathy (53%), coronary artery disease (13%), and congenital heart disease (13%), respectively. No structural heart disease was present in 20% of cases. The mean left ventricular ejection fraction was 39 ± 13%. Eighty percent of patients had sustained VA, the remaining patients presented with frequent ventricular ectopy. Ablation was performed using a conventional irrigated 4-mm tip catheter in a combination with commercially available PF generator. Peripheral venous blood samples for the assessment of the plasmatic levels of high-sensitivity troponin T (hsTnT) were obtained the next day (usually 18-24hours) after the procedure. Results A mean of 17±12 PF applications (25A) per patient were delivered. In 5 patients (33%), an additional RF ablation (4±9 applications) was performed. Acute success as assessed by non-inducibility of VA or elimination of ectopic focus was achieved in all but one patient (93%). In 4 cases (27%), PF energy was applied within the great cardiac vein and subsequent coronary angiography did not reveal any abnormality. On the other hand, transient conduction system block occurred in 3 cases (20%) during PF application on the lateral LV wall remotely from the LV septum (complete AV block in one, LBBB in two patients). These events resolved in all cases within one hour. Ablation using PF did not result in excessive increase of hsTnT (657±482ng/l, with upper reference level of 14ng/l). Conclusion Initial experience with PF for the treatment of VA indicates high acute efficacy. The long-term effect is to be determined. PF applications in the ventricle may be associated with unexpected but transient conduction system damage, even when applications are performed remotely from the interventricular septum. The postprocedural increase in plasma troponin levels is only moderate.

Dynamics of Urine Electrolytes in Term Neonates during the 1st Week of Life

Background: Urine electrolyte assessment is vital for diagnosing and managing neonatal conditions. However, the challenge of urine collection in neonates has resulted in a lack of standardized urine electrolyte reference values. Aim: This study seeks to explore the reference levels and potential trends in serum and urine electrolytes to better understand how the kidneys handle these substances. Methods: Healthy neonates were prospectively enrolled following normal births. Using biochemical methods, blood and urine samples were collected and analyzed on the 1st and 5th postnatal days. Statistical analysis was performed using descriptive statistics and the Wilcoxon matched-pairs signed-rank test. Results: This prospective study enrolled 55 healthy neonates. Significant changes in serum electrolyte concentrations were observed between the 1st and 5th days after birth. Notably, sodium, creatinine, urea nitrogen, and uric acid levels decreased, whereas potassium, calcium, and phosphate levels increased. Urine analysis revealed significant increases in the tubular maximum phosphate reabsorption per glomerular filtration rate and decreases in the fractional excretion of potassium and uric acid by Day 5. Conclusion: This study challenges prevailing assumptions about the stability of neonatal urine electrolytes and highlights dynamic changes in the first postnatal week. These insights lay the groundwork for further research into electrolyte disorders in newborns and have potential implications for improving neonatal care practices.

Establishment of Typical Dose Reference Level (DRL) Values for Adult Patients Undergoing Computed Tomography in Three Hospitals in Brazzaville, Congo Republic

The present study aimed at to establish typical dose reference level (DRL) values for adult patients undergoing computed tomography (CT) examinations in three hospitals in Brazzaville, Congo Republic. The examinations considered were head, chest, abdomen-pelvis, chest-abdomen-pelvis and lumbar spine CT scans. For each examination, the median of the distribution for the volume CT dose index (CTDIvol) and dose-length product (DLP) were determined. The median values were considered as the typical DRL values. Hypothesis testing was also carried out to statistically compare the mean values obtained for each participating CT facility. In the case of head scan, the typical values proposed in the present study in terms of CTDIvol and DLP were 15–48% and 28–60% lower than the DRL values reported in the literature, respectively. In the case of lumbar spine, the typical value determined in this study in terms of DLP was 48–70% greater than the DRL values provided in the literature. The typical values proposed for chest, abdomen-pelvis and chest-abdomen-pelvis were within the DRL values reported in the literature. It is possible that the adoption of the typical values proposed in the present study will help in reducing the dose received by adult patients undergoing CT examination in Congo Republic.

Needs analysis of applied linguistic students and their english language needs at the University of the Armed Forces ESPE

This paper deals with the procedures to collect information about the learners´ needs, which are mandatory to plan, carry out, and evaluate educational programs for either public or private institutions as a response to their real needs (Pratt 1980) to reinforce not only the contents but also the students’ background which includes their behavior as well. In this context, the University of the Armed Forces ESPE in coordination with the Department of Languages and its Career of Applied Linguistics in English let me find out if the students who already finished their curriculum have reached their competences in the language and the teacher formation to face their profession. Nowadays, The Common European Framework CEFR of Reference for Languages: Learning, Teaching, Assessment, is a guideline used to describe the achievements of learners of foreign languages in many countries including Ecuador. The last year's cohort was considered to take the sample FCE exam and analyze if the results are the ones that the government is looking for. They were classified into the six reference levels that are becoming widely accepted as the European standard for grading an individual's language proficiency.

Proposed DRLs for mammography in Switzerland

The aim of this study is to propose diagnostic reference levels (DRLs) values for mammography in Switzerland. For the data collection, a survey was conducted among a sufficient number of centres, including five University hospitals, several cantonal hospitals, and large private clinics, covering all linguistic regions of Switzerland to be representative of the clinical practice. The data gathered contained the mean glandular dose (MGD), the compressed breast thickness (CBT), the mammography model and the examination parameters for each acquisition. The data collected was sorted into the following categories: 2D or digital breast tomosynthesis (DBT) examination, craniocaudal (CC) or mediolateral oblique (MLO) projection, and eight categories of CBT ranging from 20 mm to 100 mm in 10 mm intervals. A total of 24 762 acquisitions were gathered in 31 centres on 36 mammography units from six manufacturers. The analysis showed that the data reflects the practice in Switzerland. The results revealed that the MGD is larger for DBT than for 2D acquisitions for the same CBT. From 20–30 mm to 90–100 mm of CBT, the 75th percentile of the MGD values obtained increased from 0.81 mGy to 2.55 mGy for 2D CC acquisitions, from 0.83 mGy to 2.96 mGy for 2D MLO acquisitions, from 1.22 mGy to 3.66 mGy for DBT CC acquisitions and from 1.33 mGy to 4.04 mGy for DBT MLO acquisitions. The results of the survey allow us to propose Swiss DRLs for mammography according to the examination type (2D/DBT), projection (CC/MLO) and CBT. The proposed values are very satisfactory in comparison with other studies.

DETERMINATION OF PRODUCTIVITY OF COWS IN KETOSIS USING PROBIOTICS

High-yielding cows are prone to negative energy balance due to high lactation and insufficient dry matter intake after calving. This leads to the mobilization of fat and protein in the body to meet the nutrient needs of the lactating cow. High levels of nonesterified fatty acids are maintained by fat and protein mobilization, leading to ketosis due to incomplete oxidation of ketone bodies. The purpose of the research was to investigate the effect of probiotics on the productivity of cows and the quality of milk in ketosis. Research was conducted in the period from October to November 2021 on Holstein cows in the limited liability company "Lan" Agricultural Company of the North-Eastern region of Ukraine. It was found that in cows in the post-calving group, seven days after calving, the level of ketone bodies in the blood of the cows ranged from 1.0 to 2.1 mmol/l, which is higher than in the control by 71.42–185.71%. Two weeks after probiotic administration, ketone levels were between 0.5 and 1.2 mmol/L, 16.65–100% higher than controls. On the 28th day of the study, the content of ketone bodies in cows was within the physiological norm. In cows suffering from ketosis, productivity was reduced on the seventh day of research by 22.42–336.4%, on the 14th day by 11.6–29.35%. During the study of productivity, its restoration to the indicators of healthy animals on the 28th day after calving was established at the level of 28-29 kg/day. At the same time, the content of microorganisms and somatic cells had a direct correlation with productivity, and on the 28th day, the milk of all experimental cows was suitable for consumption and corresponded to the "extra" variety. In the first week after calving, the ratio of milk fat and protein in the milk of cows with ketosis was slightly imbalanced, which is a sign of ketosis. On the seventh day of the study, the milk fat level exceeded the protein content in cow 6905 by 32%, in cow 6852 by 39.25%, in cow 6916 by 30.34%, in cow 7642 by 41.17%, in cow 6187 – by 33.62%, in cow 2563 – by 36.40%, in cow 3891 – by 41.63%. At the end of the study on the 28th day, the fat/protein ratio approached the reference level of 1:1 in all experimental animals.

Carbon carrying capacity in primary forests shows potential for mitigation achieving the European Green Deal 2030 target

Carbon accounting in the land sector requires a reference level from which to calculate past losses of carbon and potential for gains using a stock-based target. Carbon carrying capacity represented by the carbon stock in primary forests is an ecologically-based reference level that allows estimation of the mitigation potential derived from protecting and restoring forests to increase their carbon stocks. Here we measured and collated tree inventory data at primary forest sites including from research studies, literature and forest inventories (7982 sites, 288,262 trees, 27 countries) across boreal, temperate, and subtropical Global Ecological Zones within Europe. We calculated total biomass carbon stock per hectare (above- and below-ground, dead biomass) and found it was 1.6 times larger on average than modelled global maps for primary forests and 2.3 times for all forests. Large trees (diameter greater than 60 cm) accounted for 50% of biomass and are important carbon reservoirs. Carbon stock foregone by harvesting of 12–52% demonstrated the mitigation potential. Estimated carbon gain by protecting, restoring and ongoing growth of existing forests equated to 309 megatons carbon dioxide equivalents per year, additional to, and higher than, the current forest sink, and comparable to the Green Deal 2030 target for carbon dioxide removals.

National Diagnostic Reference Levels for Standard Descending Thoracic Endovascular Aortic Repair and Optimisation Strategies

The International Commission on Radiological Protection has highlighted the large number of medical specialties that use fluoroscopy outside diagnostic imaging departments without radiation protection programmes for patients and staff. Vascular surgery is one of these specialties. Thoracic endovascular aortic repair (TEVAR) is a complicated procedure requiring radiation protection guidance and optimisation. The recent EU Basic Safety Standards Directive requires the use and periodic updating of diagnostic reference levels (DRLs) for interventional procedures. The aim of this study was to determine doses for patients undergoing TEVAR with mobile Xray systems and hybrid rooms (fixed Xray systems) to obtain national DRLs and to suggest optimisation actions. This was a retrospective cross sectional study. The Spanish Chapter of Endovascular Surgery conducted a national survey in 11 autonomous communities representing around 77.6% of the Spanish population (47.33 million inhabitants). A total of 266 TEVAR procedures from 17 Spanish centres were analysed, of which 53.0% were performed in hybrid operating rooms. National DRLs were obtained and defined as the third quartile of the median values from the different participating centres. The proposed national DRLs are: for kerma area product (KAP), 113.81 Gy·cm2 for mobile Xray systems and 282.59 Gy·cm2 for hybrid rooms; and for cumulative air kerma (CAK) at the patient entry reference point, 228.38 mGy for mobile systems and 910.64 mGy for hybrid rooms. Based on the requirement to know radiation doses for standard endovascular procedures, this study of TEVARs demonstrated that there is an increased factor of 2.48 in DRLs for KAP when the procedure is performed in a hybrid room compared with mobile C-arm systems, and an increased factor of 3.98 in DRLs for CAK when the procedure is performed with hybrid equipment. These results will help to optimise strategies to reduce radiation doses during TEVAR procedures.

Expansion of Typical Values for Paediatric Patients in Ireland and Comparison with Published DRLs - Experiences of a Single Institution

IntroductionTo reduce the risks involved with ionising radiation exposure, typical values (TVs) and diagnostic reference levels (DRLs) have been established to help keep radiation doses ‘as low as reasonably practicable. TVs/DRLs provide standardised radiation dose metrics that can be used for comparative purposes. However, for paediatrics, such values should consider the size of the child instead of their age. This study aimed to establish and compare paediatric TVs for chest, abdomen and pelvis radiography. MethodsStudy methods followed processes for establishing paediatric DRLs as outlined by the Health Information and Quality Authority (HIQA). Kerma-area product (KAP) values, excluding rejected images, were retrospectively acquired from the study institution's Picture Archiving and Communications System (PACS). Paediatric patients were categorised into the following weight-based groupings (5 to <15 kg, 15 to <30 kg, 30 to <50 kg, 50 to 80 kg) and stratified based on the examination that was performed (chest, abdomen, and pelvis), and where it was performed (the different X-ray rooms). Anonymised data were inputted into Microsoft Excel for analysis. Median and 3rd quartile KAP values were reported together with graphical illustrations. ResultsData from 407 X-ray examinations were analysed. For the previously identified weight categories (5 to <15 kg, 15 to <30 kg, 30 to <50 kg, 50 to 80 kg), TVs for the chest were 0.10, 0.19, 0.37 and 0.53 dGy.cm2, respectively. For the abdomen 0.39, 1.04, 3.51 and 4.05 dGy.cm2 and for the pelvis 0.43, 0.87, 3.50 and 7.58 dGy.cm2. Between X-ray rooms TVs varied against the institutional TVs by -60 to 119 % (chest), -50 to 103 % (abdomen) and -14 and 24 %% (pelvis). ConclusionTVs in this study follow established trends with patient weight and examination type and are comparable with published literature. Variations do exist between individual examination rooms and reasons are multifactorial. Given that age and size do not perfectly correlate further work should be undertaken around weight-based TVs/DRLs in the paediatric setting.

Prognostic Value and Determinants of High-Sensitivity Cardiac Troponin T in Patients With a Systemic Right Ventricle: Insights From the SERVE Trial.

The determinants and prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) among patients with a systemic right ventricle are largely unknown. Ninety-eight patients from the randomized controlled SERVE (Effect of Phosphodiesterase-5 Inhibition With Tadalafil on Systemic Right Ventricular Size and Function) trial were included. The correlation between baseline hs-cTnT concentrations and biventricular volumes and function quantified by cardiac magnetic resonance or cardiac multirow detector computed tomography was assessed by adjusted linear regression models. The prognostic value of hs-cTnT was assessed by adjusted Cox proportional hazards models, survival analysis, and concordance statistics. The primary outcome was time to the composite of clinically relevant arrhythmia, hospitalization for heart failure, or all-cause death. Median age was 39 (interquartile range, 32-48) years, and 32% were women. Median hs-cTnT concentration was 7 (interquartile range, 4-11) ng/L. Coefficients of determination for the relationship between hs-cTnT concentrations and right ventricular end-systolic volume index and right ventricular ejection fraction (RVEF) were +0.368 (P=0.046) and -0.381 (P=0.018), respectively. The sex- and age-adjusted hazard ratio for the primary outcome of hs-cTnT at 2 and 4 times the reference level (5 ng/L) were 2.89 (95% CI, 1.14-7.29) and 4.42 (95% CI, 1.21-16.15), respectively. The prognostic performance quantified by the concordance statistics for age- and sex-adjusted models based on hs-cTnT, right ventricular ejection fraction, and peak oxygen uptake predicted were comparable: 0.71% (95% CI, 0.61-0.82), 0.72% (95% CI, 0.59-0.84), and 0.71% (95% CI, 0.59-0.83), respectively. Hs-cTnT concentration was significantly correlated with right ventricular ejection fraction and right ventricular end-systolic volume index in patients with a systemic right ventricle. The prognostic accuracy of hs-cTnT was comparable to that of right ventricular ejection fraction and peak oxygen uptake predicted. URL: https://www.clinicaltrials.gov; Unique identifier: NCT03049540.

Multi-period portfolio choice under loss aversion with dynamic reference point in serially correlated market

This paper explores a novel multi-period portfolio decision model for loss-averse investors with dynamically adapted reference points in a market with serially correlated returns. We demonstrate that the optimal policy is a piecewise linear function of the deviation between current wealth and reference level, and its slopes are a path-dependent function of the historical returns, in sharp contrast to the constant slopes generated by the simplified model that ignores the diminishing sensitivity and assumes independent returns. This distinctive characteristic significantly departs from the conventional V-shaped pattern of the risky position, leading to a more intricate nonlinear functional mapping. Our study underscores the potential pitfalls of relying on the simplified model and offers valuable insights for investors and practitioners seeking to formulate effective portfolio strategies under realistic market conditions. Furthermore, our simulation analysis indicates that the predictability of returns, coupled with a slight degree of diminishing sensitivity, may amplify the disposition effect. Lastly, we establish that the new policy also effectively addresses the multi-period mean-conditional-value-at-risk (CVaR) portfolio optimization problem in the context of correlated returns, thereby expanding the practical applications of our findings.

Dynamic model of changes in the trophic structure of an ecosystem affected by chronic radiation exposure

The conceptual dynamic ecosystem model was developed to evaluate the self-organization of trophic structure in ecosystems during the course of biogenic succession. This model was applied to analyze the possible changes in the ecosystem under impact of the anthropogenic physical stressor – chronic exposure to ionizing irradiation. The model predicts that amount of the limiting biogenic nutrient in the environment can modify the ecological effects of ionizing radiation. Negative effects of the chronic exposure are less significant in ecosystems with high food supply. The model does not show presence of any ecological effect of radiation at the exposure rates less than the derived consideration reference levels, obtained by International Commission on Radiological Protection for individual nature organisms. If the dose rates are higher than those levels, radiation exposure can affect ecological interactions between species. The model shows that environmental hormesis can exist in the ecosystems, impacted by the chronic radiation exposure. The reason of this effect is change of the ecological coefficients (for example, decrease of the predation rate), which in the certain range of parameters leads to the increase of biomasses of all species at the same amount of the limiting biogenic nutrient in ecosystem. Trigger regimes exist in the model ecosystem with mixed-feeding consumers. Within the trigger area, the realization of a particular trophic structure depends on initial species biomasses. A hysteresis phenomenon exists in such ecosystems, which means that the successive changes in the trophic structures realized following the increase of the influencing factor are not reproduced in the same order if the influencing factor was gradually decreased back to its previous values. The model predicts for this case, that the radioactively contaminated ecosystem does not necessarily return to its initial trophic structure, despite the dose rate decreases to the initial levels.

Emissions and exposure to NOx, CO, CO2 and PM2.5 from a gas stove using reference and low-cost sensors

Gas stoves and cooking are significant sources of indoor pollution. Using a combination of regulatory and calibrated low-cost sensors (LCS) we measured NO, NO2, CO and CO2 emission rates (g hr−1) and emission factors (g J−1) from a natural-gas stove and oven. The emission rates for gaseous pollutants were significantly higher, by factors of 2.6–29, from the oven compared to the stove for every pollutant measured.To evaluate the indoor air concentrations, we used a calibrated low-cost sensor (TSI Inc, AirAssure) to examine indoor concentration of CO, CO2, NO2 and PM2.5 for one month in one U.S. home with a gas stove during normal activities, including cooking. Indoor concentrations of one or more pollutants exceeded the U.S. EPA's Air Quality Index (AQI) level of 100 (for CO, NO2, and PM2.5) or 2000 ppm (for CO2) for an average of 99 min per day. The AirAssure, with only the manufacturer's calibration, was an excellent indicator of times when indoor concentrations of CO, CO2, and NO2 exceeded these reference levels. Without in-situ calibration, the AirAssure underestimated in-home PM2.5 concentrations. After in-situ calibration, the AirAssure correctly identified 1-min periods when the AQI was >100 85% of the time (up from 46% of the time without calibration).

Environmental phenol exposures in 6- to 12-week-old infants: The Infant Feeding and Early Development (IFED) study

BackgroundExposure to phenols, endocrine-disrupting chemicals used in personal care and consumer products, is widespread. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period. We aimed to describe distributions and predictors of urinary phenol concentrations among U.S. infants ages 6–12 weeks. MethodsThe Infant Feeding and Early Development (IFED) study is a prospective cohort study of healthy term infants enrolled during 2010–2013 in the Philadelphia region. We measured concentrations of seven phenols in 352 urine samples collected during the 6- or 8- and/or 12-week study visits from 199 infants. We used linear mixed models to estimate associations of maternal, sociodemographic, infant, and sample characteristics with natural-log transformed, creatinine-standardized phenol concentrations and present results as mean percent change from the reference level. ResultsMedian concentrations (μg/L) were 311 for methylparaben, 10.3 for propylparaben, 3.6 for benzophenone-3, 2.1 for triclosan, 1.0 for 2,5-dichlorophenol, 0.7 for BPA, and 0.3 for 2,4-dichlorophenol. Geometric mean methylparaben concentrations were approximately 10 times higher than published estimates for U.S. children ages 3–5 and 6–11 years, while propylparaben concentrations were 3–4 times higher. Infants of Black mothers had higher concentrations of BPA (83%), methylparaben (121%), propylparaben (218%), and 2,5-dichorophenol (287%) and lower concentrations of benzophenone-3 (−77%) and triclosan (−53%) than infants of White mothers. Triclosan concentrations were higher in breastfed infants (176%) and lower in infants whose mothers had a high school education or less (−62%). Phenol concentrations were generally higher in summer samples. ConclusionsWidespread exposure to select environmental phenols among this cohort of healthy U.S. infants, including much higher paraben concentrations compared to those reported for U.S. children, supports the importance of expanding population-based biomonitoring programs to infants and toddlers. Future investigation of exposure sources is warranted to identify opportunities to minimize exposures during these sensitive periods of development.

Clinical diagnostic reference levels in neuroradiology based on clinical indication.

This study focuses on patient radiation exposure in interventional neuroradiology (INR) procedures, a field that has advanced significantly since its inception in the 1980s. INR employs minimally invasive techniques to treat complex cerebrovascular diseases in the head, neck, and spine. The study establishes diagnostic reference levels (DRLs) for three clinical indications (CIs): stroke (S), brain aneurysms (ANs), and brain arteriovenous malformation (AVM). Data from 209 adult patients were analyzed, and DRLs were determined in terms of various dosimetric and technical quantities. For stroke, the established DRLs median values were found to be 78Gycm2, 378mGy, 118mGy, 12min, 442 images, and 15 runs. Similarly, DRLs for brain AN are 85Gycm2, 611mGy, 95.5mGy, 19.5, 717 images, and 26 runs. For brain AVM, the DRL's are 180Gycm2, 1144mGy, 537mGy, 36min, 1375 images, and 31 runs. Notably, this study is unique in reporting DRLs for specific CIs within INR procedures, providing valuable insights for optimizing patient safety and radiation exposure management.

Exploring Contextual Factors in Vagal Tank Theory

High baseline Heart rate variability (HRV) is a putative measure of resilience which predicts adaptive HRV changes during (Reactivity) and after (Recovery) a stressor according to Vagal Tank Theory. However, we do not understand how the availability of resources prior to a stressor impacts this relationship. Using an ecological framework, we tested VTT hypotheses while examining receptivity to social presence and contemplative practices as a moderator to Reactivity and Recovery during a subsequent stressor. Using ECG, we modeled HRV as the root-mean square of successive R-R intervals (RMSSD) across four conditions: baseline, post contemplative practice, directly before a CO2 breathing tasking, while breathing CO2, and after CO2. Reactivity and Recovery were defined as the usual subtraction for phasic HRV literature, while Receptivity was modeled as post contemplative practice HRV minus baseline. Our multiple regression analyses showed that higher baseline predicted greater reactivity, positively interacting with the female gender and the partner condition (F(9,83)=2.00, p=0.04). Higher baseline predicted lower recovery HRV with no significant interactions (F(9,85)=2.66, R2=0.22, p=0.009), potentially due to the benefit in the HRV level at the reference level (after contemplative practice). Higher receptivity predicted higher recovery, with women showing the strongest relationship (F(4,88)=16.3, R2=0.43, p&lt;0.001). Our results suggest that both baseline and receptivity to resources may impact resilience to stress, and that future research should account for gendered effects. Cornell University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A DIRECT COMPARISON OF TWO OBJECTIVE METHODS FOR DETECTION OF NON-ADHERENCE IN PATIENTS WITH UNCONTROLLED HYPERTENSION

Objective: Uncontrolled hypertension remains a major health challenge leading to premature death and cardiovascular morbidity. We have previously reported a prevalence of non–adherence to antihypertensive drugs from 8-30% of patients studied by either directly observed therapy (DOT) or serum drug concentrations (S- conc.) of antihypertensive medication. We aimed to investigate the prevalence of non–adherence in patients with uncontrolled hypertension consecutively referred to our outpatient clinic and to compare results from DOT and s-conc. in the same patient. Design and method: Nine, of planned 20 patients referred to 24-hour ambulatory blood pressure measurement (ABPM) were included in these preliminary results. Inclusion criteria was uncontrolled blood pressure (office SBP &gt;140 mmHg) despite the use of three antihypertensive drugs. ABPM were measured at baseline and repeated after 3-4 weeks, the second time following DOT. S-conc. of antihypertensive drugs were measured by ultra-high-performance-liquid-chromatography tandem mass spectrometry at baseline and 24 hours after DOT. Patients with s-conc. of at least one drug below a predefined reference level were considered to be non–adherent. At the final visit patients evaluated how they experienced the DOT and s-conc. measurements by a visual analogue scale (VAS score) from 0 –10. Results: Of nine patients (age 36-79), five adherent (54,5%) and four (45,5%) non-adherent were detected by s-conc. Baseline mean for Ambulatory systolic blood pressure (ASBP) at visit one was 138±19 mmHg and mean ASBP after DOT 134±14 mmHg (p = 0,33). ASBP fell by 12±9 mmHg after DOT in the non-adherent group compared to a rise by 2±10 mmHg in the adherent group (p=0,079). Five patients completed the VAS evaluation, none of them experienced DOT or measuring s-conc. unpleasant. Conclusions: The difference in ASBP after DOT in the two groups showed a clear trend. Preliminary data in patients with uncontrolled hypertension show that both DOT and measurement of serum concentrations of antihypertensive drugs are reliable methods for detecting non–adherence and are well accepted by the patients. These methods may be used complementary in the outpatient clinic.