bluuebunny/crossref_metadata_2025 huggingface dataset:
381b - Advancements in the measurement for respirable crystalline silica to improve the determination of worker’s personal exposures
Authors: Stacey, Peter
Published: June 2024

This presentation will discuss the work conducted at the Health and Safety Executive’s (HSE) science and research centre over the last 10 years and the advantages and limitations of new developments for the measurement of workers’ personal exposures to respirable crystalline silica (RCS). HSE has investigated and evaluated new measurement technologies for determining RCS exposures more accurately at lower concentrations (below the workplace exposure limit) where there remains a risk of respiratory ill health. It is estimated that 560,000 workers are potentially exposed to aerosols containing RCS in the United Kingdom, which can cause debilitating lung diseases like silicosis and cancer.

Measurement science is undergoing a period of technological development. Current research focuses include, use of new sensitive Raman instrumentation, the miniaturisation of instruments and ability to provide RCS measurements on-site (without the need for laboratory analysis), and computational methods to improve RCS quantification when mineral interferences are present. These options have enabled us to improve the measurement of RCS in the laboratory and provide end-of-shift personal RCS exposures.

For example, HSE have demonstrated that Raman instrumentation can give limits of detection that are potentially low enough (~200 ng) to measure RCS in samples collected from behind respirators. In addition, chemometric programmes were shown to improve the accuracy of Fourier transform infrared (FTIR) analysis for RCS measurement when mineral interference is present.

Although each approach has benefits, the latter, i.e., on-site portable FTIR instruments with chemometric methods, may offer an overall practical improvement when monitoring workers personal exposures to RCS.

Crown copyright (2024)
21 Total Worker Health® and critical risk management
Authors: Wilk Nancy
Published: June 2024

Global estimates of the work-related burden of disease and injury indicate that each year 1.9 million people die from exposure to occupational risk factors, 81% of these fatalities resulting from non-communicable, occupational diseases. These are underestimates of the burden of occupational exposure and disease. We are not effectively preventing occupational disease and related fatalities through the classical approaches to occupational safety and health and risk management. There is an urgent need for alternate strategies to prevent occupational illness. Total Worker Health® (TWH®), introduced by NIOSH in 2011, offers an approach for consideration that could serve as a model across geographies and sectors to improve worker wellbeing, mitigation of risk, and ultimately, prevention of occupational disease and related fatality. This presentation will include the recent global estimates of non-communicable, occupational disease published by the World Health Organization and International Labour Office in 2021, and a review of the International Council on Mining and Metals’ Critical Control Management (CCM) process. TWH® will be defined and issues related to advancing worker wellbeing will be introduced. The other “Totals” and their relationships to TWH will be explained. The presentation will highlight the challenges in applying the CCM approach to critical risks associated with overexposure to chronic occupational health hazards such as silica and other carcinogens. In these intersecting topic areas, occupational hygienists and other OEHS professionals as exposure scientists can have meaningful input into prevention strategies and programs and improved worker health outcomes. Collaborative opportunities offering sustainable solutions will be introduced and discussed.
51 Does antique Waterford Crystal create a lead exposure if used to serve wine or other alcohol beverages
Authors: Napier Dan , Williams Taylor
Published: June 2024

Historically Lead was added to crystal glasses and bottles that were decorated by cuts in the glass. Crystal from Waterford Ireland was very popular. The author selected various Genuine antique Waterford crystal glasses and crushed them to determine if there was any potential exposure to lead from consuming wine or hard liquor that had been placed in a Waterford cut crystal glass. Further testing was accomplished by placing citric acid in cut crystal bottles for several months to determine if the lead was detectable in the stored liquid in a Waterford bottle.

Wine and Cognac were placed in Waterford bottles or on crushed glass to simulate normal use.

The study is ongoing, but expected to be available for review by February, 2024.
69 Association of aerodynamic size of bioaerosols with biodiversity and antibiotic-resistance in kindergartens
Authors: Lai Chane-Yu , Lin Tzu-Hsien , Chou Ying-Hsiang , Hsu Tzu-Yu
Published: June 2024

The bacterial size, biodiversity, human-associated bacteria (HAB) and antibiotic-resistance of bioaerosols were evaluated at three kindergartens in Taiwan in winter and spring. Kindergartens A, B, and C were in urban, semi-urban, and rural areas, respectively. A six-stage viable Andersen cascade impactor was used to collect bioaerosols and to determine their size distributions. A BD Phoenix-100 automated interpretation system was used to identify the airborne bacteria species and their antibiotic resistance.

The results revealed that 1,425 colonies (97.6%) of the sampled airborne bacteria contained 63 species in 29 genera, and 56.6-86.4 % were HABs. About 84.8 % of selected airborne bacteria revealed antibiotic-resistance to at least one antibiotic agent. Staphylococcus spp. was detected in all sampling rounds in the three kindergartens, with a range of abundance between 2.0 and 70.0%. They resisted to 16.9-25.0% of tested antibiotic agents and their sizes varied widely from 1.1 to >7.0 µm. The urban-area kindergarten yielded higher bacteria antibiotic-resistant rate and multidrug resistance than did the lower urbanization level kindergartens. The statistical results revealed that the kindergarten in the rural area, with a higher temperature, a lower relative humidity, and a lower CO2 concentration than the others, tended to have the largest biodiversities (P < 0.05). Moreover, bioaerosol aerodynamic size was statistically correlated with Shannon (P = 0.001) and inverse Simpson (P = 0.002) diversities.

Airborne HAB, especially belonged to Firmicute, that coagulated with human flakes and had high multidrug resistance rate might increase indoor transmission under poor ventilation in kindergarten.
97 Performance of pharmaceutical equipment – challenges during exposure monitoring
Authors: Labatzke Ramona
Published: June 2024

Situation

When new equipment is installed in pharmaceutical industries an APCPPE test (former SMEPAC) should be performed to collect knowledge about the exposure profile of the equipment. The APCPPE test should be performed in the operational qualification phase (OQ) of the equipment.

Lessons Learned

In reality there are a lot of challenges to do adequate performance testing. In addition, evaluation of results and drawing conclusions is not always easy. Handpicked examples of performance testing demonstrate challenges during exposure monitoring. Challenges during evaluation are presented as well.
104 Evaluating multi-establishment SEG variability: results from the brick manufacturing sector
Authors: Emili Andrea , Mater Gautier
Published: June 2024

The seminal works of Rappaport (1991) and Kromhout et al. (1993) highlighted the importance of Similar Exposure Group (SEG) variability in occupational exposure assessment. In 2019, we started a research program to test a methodology for defining multi-establishment SEGs, i.e. groups including workers from different establishments, as opposed to the usual “mono-establishment” approach. Our research included both data from two French occupational exposure databases, managed by INRS, and the field observations and measurements we performed in various industrial sectors. To be included in our analysis, establishments had to share similar characteristics and occupational hygiene standards. Here we present results from the brick manufacturing sector, showing the effect of workplace on SEGs variability. For this sector, we collected 252 personal measurements of crystalline silica, covering 8-hour shifts. We estimated by ANOVA the within- and between- components of SEGs variability and we calculated for each SEG the rho heterogeneity coefficient and the R ratio, which were initially proposed for assessing worker variability. Rho values were comprised between 0.001 and 0.49, with a median of 0.12. The R ratio was comprised between 1.15 and 4.46, with a median of 2.70. Results showed moderate variability for five out of eight inter-establishment SEGs, high variability for two SEGs and low variability for one SEG, in good agreement with the results obtained by expertise. Future analyses will aim at better define homogeneity criteria for multi-establishment SEGs, taking into account their higher complexity compared to the classic mono-establishment SEGs.
159 Efficacy of different types of masks in protecting the environment and individual
Authors: Cheng Hsiao Chi , Chiu Ching Yi , Lin Chih Wei , Huang Sheng Hsiu , Chen Chih Chieh
Published: June 2024

This study addresses the pivotal issue of mask effectiveness in safeguarding individuals and the environment, especially in the context of various disease outbreaks. Highlighting the dual purpose of masks – personal protection and environmental safety – the research emphasizes the challenges posed by leakage and filtration efficiency. The study’s background underscores the critical need for understanding mask efficacy to guide public health practices effectively. The research employed a comprehensive approach, utilizing silicone tubes to simulate mask leaks and polydisperse sodium chloride particles as challenge aerosols. Various parameters, such as breathing flow rates, types of masks, and leak locations, were meticulously examined. The study utilized an Aerodynamic Particle Sizer to measure particle concentration and size distribution, offering a detailed analysis of mask performance under different conditions. Findings revealed significant insights into mask efficacy. Higher breathing flow rates notably improved mask protection efficiency, showcasing the relationship between airflow rates and mask effectiveness. Interestingly, masks with superior filtration efficiency but poor fit exhibited reduced protection, emphasizing the crucial role of proper mask fit in ensuring efficacy. The study demonstrated the impact of leak location on particle penetration, providing essential data for mask design and selection. This research offers vital guidelines for environment-specific mask selection, emphasizing the pivotal role of proper fit. It addresses the potential reshaping of public health strategies during mask shortages by highlighting the need for balancing filtration efficiency and fit. These insights offer practical solutions for individual and environmental safety. Moreover, they could inform future public health policies and manufacturing standards, enhancing disease prevention strategies and contributing significantly to global health security.
160 Performance improvement of beta gauge particulate monitors
Authors: li Qi-Xiang , lin Chih-Wei , Huang Sheng-Hsiu , Chen Chih-Chieh
Published: June 2024

The Beta gauge is used in PM monitoring. It measures particle mass by utilizing beta attenuation. However, due to the high deviation of beta particles per second, commercial beta gauges have a high response time. That means achieving real-time monitoring is challenging. This study aims to improve the beta gauge’s detection limit(LOD) and response time(TR) for real-time monitoring. To reduce external environmental interference, aerosol generation system was established in laboratory to generate stable challenge particle size and distribution. The commercial beta gauge was used to evaluate the effects of the sampling area, sampling number, and smoothing time(TS). Lambert Beer’s law was used to convert the beta intensity into mass concentration per second, evaluating the beta gauge’s TR, S/N ratio, and LOD. By adjusting TS from 5 to 75 min, TR reaches from 0.3 to 60 minutes. At daily average PM2.5 of 35 μg/m3, the SD of readings decreases from 175 to 3.2 μg/m3. At quantitative standard (S/N ratio=10), when the sampling area is reduced from 2 to 0.4 cm2, the required TS is shortened by 33%. When the sample number is increased to 6, the required TS can be shortened by 60%. The LOD is about 12 μg/m3 with TS of 75 minutes. By increasing the sample number to 6, it can be achieved 1.5 μg/m3. To optimize its response time, the smoothing method can be utilized. To improve the stability of beta gauge measurement and achieve a lower LOD, it is recommended to reduce the sampling area and increase the number of samples.
173 A snapshot of occupational health and safety concerns from the 1955 hotline among migrant workers in Taiwan
Authors: Liu Yu-Kang , Liu Kuo-Ching , Tsaur Charng-Cheng , Lee Wan-Chen
Published: June 2024

Migrant workers are more likely to engage in high-risk occupational activities, making job-related health and safety a persistent concern. However, there is a lack of research on the migrant workers’ perception on work-related difficulties and complaints to inform future policy formulation regarding workers’ wellbeing. Therefore, the objective of this study was to investigate the occupational challenges faced by migrant workers in Taiwan. We analyzed data recorded between 2012 to 2021 from the 1955 Labor Advisory and Complaints Hotline database. Based on the built-in categorical variables and selected keywords, we examined the basic characteristics of the complaint cases, including time trends, demographic features, and the types of issues covered in the complaints.

The results showed a stable demand for the 1955 Hotline calls over the past decade. The characteristics of complainants were similar among migrant workers across different geographic regions and industries in Taiwan. In terms of the complaint content, it was evident that most issues were centered around administrative management, such as occupational injury compensation, wages, and leave. The findings indicated that in the formulation of policies related to migrant workers, the roles played by employers and human resource companies should be taken into consideration.

This study is the first to report findings from the 1955 Hotline in Taiwan. It provides the foundation for designing more in-depth research to reveal the most pressing occupational issues that concern the migrant workers, including influential factors for safety and health.
188 The butterfly effect of emissions-based maintenance: small change in preventative maintenance has significant impact on breakdowns and exposure risk
Authors: Swanepoel Johannes (Deon) , Hines Jennifer , Gopaldasani Vinod , Badenhorst Cas J , Davies Brian
Published: June 2024

Introduction

Emissions-based maintenance (EBM), a key aspect of diesel exhaust control, serves as an effective approach to persuade workplaces to manage diesel exposure risk. EBM is an emissions source control that simultaneously contributes to improved fuel combustion efficiency and evaluates exhaust aftertreatment effectiveness. This presentation delves into a research study examining the impact of EBM on engine corrective and breakdown maintenance for an underground diesel fleet.

Methods

Bivariate and negative binomial regression analyses were conducted on data spanning five years before and after the introduction of an EBM program. The engine sample comprised 35 engines from Perkins and Caterpillar brands.

Results

Initial analysis reveals a significant reduction in breakdown maintenance following the adoption of EBM (P < 0.05). Before EBM’s implementation, there was an exponential increase in corrective maintenances annually. However, post-EBM, a significant exponential decrease in corrective maintenances was observed year-on-year (P < 0.05). These results support claims that EBM reduces engine maintenance. Furthermore, it suggests that the capital and operating costs of implementing an EBM program may be offset by the gains in reduced unscheduled maintenance.

Conclusions

This study underscores that EBM’s benefits extend beyond health risk mitigation and fuel savings. By also curbing maintenance-associated expenses, EBM offers a compelling financial reason for employers to adopt this control strategy. Consequently, this research propels diesel particulate matter (DPM) exposure control by highlighting the monetary advantages of an EBM initiative.

Research where production incentives are quantified as part of risk control can facilitate early hazard control and lay the foundation for developing real-time monitoring, by demonstrating productivity gains from implementing hazard control.
194 Permeation test for a chemical protective glove against mixtures of two chemicals
Authors: Uehara Takumi , Mogi Satoshi , Hanaoka Saki , Noguchi Makoto
Published: June 2024

We conducted a permeation test of a chemical protective glove made with neoprene and nitril against a mixture of two chemicals.

We applied three agents such as (1) methanol and water, (2) methanol and 2-propanol, and (3) toluene and hexane.

As a part of results, the breakthrough time of the agent of methanol and water increased as the methanol concentration decreased, and when methanol concentration is 10 % we found that the maximum penetration rate is lower than 0.1 μg/cm2 per minute. We will also report the permeation test results for other chemical mixtures.
205 A comparison of amended occupational exposure limits (maximum limits) promulgated in South Africa with limit values from other countries
Authors: Du Preez Karen , Claassen Nico
Published: June 2024

South African occupational exposure limits for hazardous chemical agents were revised in 2021 and introduced some limit values that were lowered by up to 99.2% when compared with the previously applicable limit values.

A descriptive study was conducted as desk research to identify exposure limits from a list typically applicable to carcinogens, mutagens, teratogens, or sensitizers, called maximum limits, that were lowered substantially. The percentage reduction in maximum limits were calculated to identify those that were reduced by more than 50%, constituting more stringent limits. These limit values were compared with limit values applied by other countries or organizations by accessing the GESTIS-ILV database which provide an overview of limit values included in 35 lists from 29 countries. The database was updated in 2022 and include two lists from South Africa. The comparison was conducted to obtain an understanding of international alignment of South African maximum limits after amendment. The range of limit values and the value reported most frequently for each chemical were reported.

A total of 21 maximum limit values were identified that were lowered by more than 50%, with six limit values lowered by 90% or more. The mode applicable to nine of the chemicals were still more stringent than the lowered South African limit values, and three were equal to the lowered limits.

The revision improved alignment of South African occupational exposure limit values with those applied in other countries, which, provided efficient implementation, translates into better protection of the workforce from occupational diseases.
212 Occupational safety and health issues among migrant workers in Taiwan
Authors: Tsai I-Hsuan
Published: June 2024

Well-functioning occupational safety and health (OSH) programs have been the foundation to strengthen global economic development. OSH policies and practices for migrant workers are issues of concern to all countries worldwide, as mentioned by the Sustainable Development Goals (SDGs). Migrant workers face various factors that exacerbate their vulnerability, including language barriers, lack of access to training and education, limited legal protection, and discrimination.

Taiwan, like many high-income countries, relies heavily on migrant workers. However, information on occupational accident prevention strategies for migrant workers is lacking, making it difficult to comprehensively evaluate the risk factors and the effectiveness of education and training. Despite implementation shortcomings, the Labor Insurance coverage requirements for migrant workers in Taiwan have provided a comprehensive database to demonstrate statistical information and to identify critical risk factors.

This study utilized the databases of labor insurance and the major occupational accidents to identify the incidence rate of work-related accidents among migrant workers compared with domestic workers in Taiwan. Meanwhile, the on-site investigation was also conducted through questionnaires and interviews with the managers, domestic laborers, and migrant workers to gain insight into their OSH experiences, perceptions, and challenges. Overall, language barriers were found to be the most prevalent obstacles in delivering effective training programs, and a reliable evaluation system is needed to assess the efficacy of the training for migrant workers.

Overall, this study offers insights for developing training programs to enhance workplace safety, fostering international collaborations for global occupational health improvement, and guiding governments in formulating policies to safeguard migrant workers’ rights and well-being.
238 The effectiveness of alarm management bundle in reducing alarm fatigue and burnout among nurses
Authors: Oktayani Pande , Lin Ro-Ting
Published: June 2024

Background

Alarm become global concern due to its patient safety and mental health issues among clinical workers. Overwhelmed by numerous false alarms not only induced alarm fatigue but also burnout. Alarm management bundle of CEASE has been widely used to decrease alarm fatigue, however the evidence of CEASE bundle in lowering both alarm fatigue and burnout is unknown.

Objective

To evaluate the effectiveness of alarm management bundle in reducing alarm fatigue and burnout among nurses.

Methods

A prospective cross-sectional study involved 110 nurses in Bali Mandara Hospital Bali. The study was divided into four sections (pretest, education, alarm management implementation of CEASE checklist and post-test) from August 1st to November 30th, 2023. Translated Alarm fatigue and Copenhagen Burnout Inventory Questionnaire were used to assess the main variables.

Results

Our preliminary result revealed the alarm fatigue score was high, 40.05±15.7. The overall burnout score was low 29.4±14.6. In the meantime, personal burnout, work-related burnout, client-related burnout shows 39.7±15.6, 30.7 ± 17.4 and 15±16.7 respectively. In the meantime, personal burnout, work-related burnout, client-related burnout revealed 39.7±15.6, 30.7 ± 17.4 and 15±16.7 respectively.

Conclusion

Our ongoing research highlights the high alarm fatigue score pre implementation of alarm management. Despite the burnout score remaining low, this study sets the stage for the implementation of the CEASE bundle to address alarm fatigue and prevent burnout. The implications of our result extend beyond smart technology utilization, alarm management policy, influencing occupational health guidelines, ultimately promoting a safer and healthier workforce.
240 Leveraging factory acceptance tests for enhanced noise control strategies, a Petronas experience
Authors: Mustaffa Masfarita , Hamis Norhana Abdul
Published: June 2024

Noise control has become a critical consideration in various industries to ensure a safe and comfortable working environment while adhering to regulatory standards. Buy Quiet Strategy is an approach aimed at reducing noise pollution and protecting the hearing health of workers. It involves making decisions that prioritize quieter equipment and design. The key concept behind Buy Quiet is to select and purchase tools, machines, and equipment that produce less noise during operation. In PETRONAS, implementing Buy Quiet strategy during design stage is crucial to optimally minimizing noise emissions at the source by selecting or designing quieter equipment.

Factory Acceptance Tests (FATs) is one of the essential components of Buy Quiet strategy, but their potential benefits extend beyond mere quality control. The paper outlines the various stages of a Factory Acceptance Test, emphasizing the importance of detailed inspection and performance evaluation. This paper also delves into the benefits of early noise control intervention through FATs, including cost savings through design modifications, reduced downtime, and enhanced compliance with noise regulations. By prioritizing noise control at the manufacturing stage, companies can create a competitive advantage by delivering quieter, more environmentally responsible products.
258 An evaluation of respirable and submicron elemental carbon measured using the NIOSH analytical method 5040 in low concentration diesel environments
Authors: Bullock William
Published: June 2024

Airborne particles containing diesel particulate matter (DPM) continue to be a focus of scientific and regulatory interest. Assessing the effectiveness of sampling devices for respirable and submicron DPM in low-concentration environments (e.g., < 20 µg/m3) is essential as authoritative standards and guidance organizations begin to develop occupational exposure limits (OELs) for DPM. Much of the current research and method development is focused on sampling DPM in underground mines due to their limited ventilation and restricted space. In the present study, the National Institute of Occupational Safety and Health Method 5040 (modified for respirable and submicron) elemental carbon (EC) was used to determine if EC would be detectable in low-concentration environments using currently available sampling equipment. Sixty-three samples were collected in locomotive mechanical shops and a truck stop using 3 different side-by-side samplers to simultaneously collect total, respirable and submicron fractions of EC. A standard 37-mm cassette was used for the total fraction of EC (TEC), a 25-mm cassette equipped with a respirable dust cyclone (GK 2.69) was used for the respirable fraction of EC (REC), and a SKC diesel particulate cassette (SKC P225317) was used to collect the submicron fraction of EC (SMEC). The geometric mean (GM) for the TEC samples was 1.75 µg/m3. The geometric mean (GM) for the REC samples was 0.2 µg/m3. The GM for the SMEC samples could not be calculated because 100% of the samples were below the limit of detection (LOD). Results demonstrate the need for a better sampling device that can achieve a detectable level of submicron DPM in low concentration environments.
263 Emission factors and fume generation rates of particles from various welding processes
Authors: Khaligh Mozhgan , Hashisho Zaher , Debia Maximilien , Hamre Doug , Wood Gentry , Quemerais Bernadette
Published: June 2024

Welding fumes are classified as a class 1 carcinogen, according to IARC. A conical chamber was built to determine emission factors and fume generation rates of particles from various welding processes. The chamber was calibrated according to the American Welding Society (AWS) standard F1.2:2013 and a high-volume air sampling pump was fixed to the top of the chamber to collect the fumes on 293 mm glass fibre filters located between the cone and the pump. Two welding processes were tested: gas metal arc welding (GMAW) and low power density laser beam welding (LLBW). Tests were performed using seven different types of consumables and different base materials. Consumables included ER70S-2, ER70S-6, ER70S-3, ER308L, ER316L, E316LSi, and ER5356 and the base materials included mild steel, stainless steel, and aluminium. Except for aluminium, which could not ne weld with this particular LLBW machine, the same consumables were used for GMAW and LLBW. Three levels of welding voltages in GMAW and power settings in LLBW were used for each type of consumable to see the effect of voltage and power on particle emission factors and fume generation rates. Additionally, differences between particle emission factors and fume generation rates from GMAW and LLBW for each consumable were compared. Emission factors and fume generation rates increased with increasing voltage/power. Although the fume generation rates were lower for LLBW than for GMAW, the emission factors were higher for LLBW.
306 Proactive prevention of irritant contact dermatitis
Authors: Taylor Helen
Published: June 2024

Irritant contact dermatitis remains the most significant occupational skin disease. The potential impact this condition has on allergic and other systemic ill-health effects means that skin damage has much wider implications. Even before clinical symptoms appear this increased risk of other health issues exists, therefore a proactive approach to preventing irritant contact dermatitis has greater benefits than just prevention of irritant contact dermatitis.

This presentation will briefly outline the importance of detecting subclinical irritant damage. A selection of techniques will be described that can help us detect subclinical irritant damage so that action can be taken prior to the clinical signs. How best to use these techniques will be discussed.
Apomixis beyond trees in the Brazilian savanna: new insights from the orchid Zygopetalum mackayi
Authors: da Costa Gleicyanne Vieira , Alves Mariana Ferreira , Duarte Mariana Oliveira , Caetano Ana Paula Souza , Koehler Samantha , Mayer Juliana Lischka Sampaio
Published: June 2024

n the Neotropics, the focus of apomictic studies predominantly centres on trees within the Brazilian savanna, characterized, mostly as sporophytic and facultative, associated with polyploidy and polyembryony. To enhance our understanding of the mechanisms governing apomixis and sexual reproduction in tropical herbaceous plants, we clarify the relationship between apomixis, chromosome counts, and polyembryony in the epiphytic orchid Zygopetalum mackayi, which forms a polyploid complex within rocky outcrops in both the Brazilian savanna and the Atlantic forest. To define embryo origins and describe megasporogenesis and megagametogenesis, we performed manual self-pollinations in first-day flowers of cultivated plants, considering all three cytotypes (2x, 3x, 4x) of this species. Flowers and fruits at different stages were collected to describe the development and morphology of ovules and seeds considering sexual and apomictic processes. As self-pollination treatments resulted in high fruit abortion in diploids, we also examined pollen tube development in aborted flowers and fruits to search for putative anomalies. Megasporogenesis and megagametogenesis occur regularly in all cytotypes. Apomixis is facultative and sporophytic, and associated with polyploid cytotypes, while diploid individuals exclusively engage in sexual reproduction. Polyembryony is caused mainly by the production of adventitious embryos from nucellar cells of triploids and tetraploids, but also by the development of multiple archesporia in all cytotypes. Like other apomictic angiosperms within the Brazilian savanna, our findings demonstrate that apomixis in Z. mackayi relies on pollinators for seed production. We also consider the ecological implications of these apomictic patterns in Z. mackayi within the context of habitat loss and its dependence on pollinators.
Common mistakes in biostatistics
Authors: D'Arrigo Graziella , El Hafeez Samar Abd , Mezzatesta Sabrina , Abelardo Domenico , Provenzano Fabio Pasquale , Vilasi Antonio , Torino Claudia , Tripepi Giovanni
Published: June 2024

Biostatistics plays a pivotal role in developing, interpreting and drawing conclusions from clinical, biological and epidemiological data. However, the improper application of statistical methods can lead to erroneous conclusions and misinterpretations. This paper provides a comprehensive examination of the most frequent mistakes encountered in the biostatistical analysis process. We identified and elucidated 10 common errors in biostatistical analysis. These include using the wrong metric to describe data, misinterpreting P-values, misinterpreting the 95% confidence interval, misinterpreting the hazard ratio as an index of prognostic accuracy, ignoring the sample size calculation, misinterpreting analysis by strata in randomized clinical trials, confusing correlation and causation, misunderstanding confounders and mediators, inadequately codifying variables during the data collection, and bias arising when group membership is attributed on the basis of future exposure in retrospective studies. We discuss the implications of these errors and propose some practical strategies to mitigate their impact. By raising awareness of these pitfalls, this paper aims to enhance the rigor and reproducibility of biostatistical analyses, thereby fostering more robust and reliable biomedical research findings.
Radiomic analysis of computed tomography myocardial texture: a new tool to identify sublclinical cardiac amyloidosis
Authors: Maragna R , Lo Iacono F , Guglielmo M , Baggiano A , Frappampina A , Fusini L , Tassetti L , Volpe A , Junod D , Del Torto A , Fontana M , Treibel T , Moon J , Corino V , Pontone G
Published: June 2024

Background

Cardiac amyloidosis (CA) is an increasingly diagnosed disease sharing several phenotypical features with aortic stenosis (AS).

Purpose

As diagnosing the two diseases has crucial prognostic and therapeutic implications, this study aims to identify a set Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation of stable and discriminative radiomic features derived from cardiac computed tomography (CT) to differentiate them.

Methods

21 patients with cardiac amyloidosis (CA) and 44 with aortic stenosis (AS) were randomly extracted from our database. All patients underwent CT scan. After image preprocessing, 107 radiomics features pertaining to shape and size, first-order statistics and textural classes, were extracted on the LV wall 3D-volume. Radiomic feature selection was based on stability, non-redundancy and relevance based on the Wilcoxon test followed by LASSO algorithm. All these steps were performed on the training set and then applied on the validation and test set. A nested cross-validation, composed of a 7-fold outer cross-validation and a 7-fold inner cross-validation, was performed, using five classifiers (k-nearest neighbors, support vector classifier, decision tree, logistic regression and gradient boosting). Four additional ML models were implemented including: I) age and sex; II) age, sex, BMI, LVEDVi and LVESVi, LV EF and IVS thickness; III) radiomic features, age, and sex; IV) radiomic features and variables included in II).

Results

Feature selection steps reduced the number of features to 10. As logistic regression showed the best performances in the validation set, it was selected for test set prediction obtaining an AUC of 0.92, sensitivity and specificity of 0.857 and 0.864 respectively. ROC curves for the test set, were computed using radiomic features (Figure 1a) and/or clinical variables (Figure 1b). The greatest performances were observed in model IV (AUC=0.96).

Conclusions

The application of radiomics shows promising results in distinguishing left ventricle hypertrophy caused by CA from AS and might be used as a noninvasive tool able to support clinical decision making.
Left atrial volume by cardiac computerized tomography using 3D reconstruction prior to catheter ablation: correlation with echocardiography and clinical outcomes
Authors: Aguiar Neves A I , Nunes F , Leite M , Teixeira R , Almeida M , Lobo A , Almeida J , Fonseca P , Ribeiro Silva M , Oliveira M , Goncalves H , Faria R , Ferreira N , Primo J , Fontes-Carvalho R
Published: June 2024

Introduction

Accurate measurement of left atrial volume index (LAVI) using transthoracic echocardiography (TTE) may be challenging. The use of cardiac computed tomography angiography (CTA) for catheter ablation planning in patients with atrial fibrillation (AF) is common and may help to reduce some of the difficulties in accurately measuring left atrial (LA) volumes, particularly with the use of three-dimensional (3D) reconstruction techniques. However, this method is not yet fully validated.

Methods

Retrospective cohort including patients who underwent an index pulmonary vein isolation (PVI) procedure using CLOSE-protocol guided radiofrequency ablation (between 2018 and 2021 in a tertiary centre. Patients with moderate to severe valvular disease, congenital heart disease or rheumatic valvular disease were excluded. Cardiac CTA was performed in all patients prior to the procedure and 3D reconstruction of the LA was performed using an open-source imaging software. Echocardiographic LAVI measurements were based on the biplane method of disks. LA enlargement was defined by LAVI ≥ 55 ml/m2 on cardiac CTA or LAVI ≥ 35 ml/m2 on TTE.

Results

120 patients (38% female; mean age 58 ± 9.5 years; 68% with a diagnosis of paroxysmal AF) were included in this analysis. Median follow up after PVI was 29 ± 6.5 months. Thirty-nine patients (33%) suffered AF recurrence during this period (after a blanking period of 90 days), of whom nine patients (7.5%) underwent a reablation procedure.

The median LAVI on TTE in this population was 36 ± 5.5 ml/m2. Sixty-seven patients (56%) had LA enlargement when considering a cut-off of LAVI ≥ 35 ml/m2 on TTE. When considering cardiac CTA-derived values after 3D reconstruction of the LA, the median LAVI was 48 ml/m2 and 37 patients (31%) had LA enlargement when considering a cut-off of LAVI ≥ 55 ml/m2 on cardiac CTA. Thirty-four patients had LA enlargement according to both cardiac CTA and TTE measurements. LA measurements using cardiac CTA and TTE strongly correlated with each other, with a correlation coefficient of 0.612 (p<0.001) .

In this cohort, no differences were found with regards to late recurrence or reablation procedures in patients with or without LA enlargement as defined by the cut-offs for LAVI on TTE (LAVI ≥ 35 ml/m2) or cardiac CTA (LAVI ≥ 55 ml/m2). Also, there were no significant differences in atrial volumes derived from TTE or cardiac CTA in patients who suffered AF recurrence when compared to those who did not.

Conclusions

LA volume measurement using 3D reconstruction techniques on cardiac CTA images may be a reasonable alternative to TTE measurements. LA enlargement, independent of measurement technique, did not predict AF recurrence in this population.
Accuracy of computed tomography angiography for the exclusion of coronary artery disease before transcatheter aortic valve implantation
Authors: Lopes V , Almeida P , Fernandes R , Cunha G , Moreira N , Ramalho A , Teixeira R , Goncalves L
Published: June 2024

Introduction

Evaluation for coronary artery disease (CAD) is recommended before transcatheter aortic valve replacement (TAVR). In most cases, this is done with invasive coronary angiography (ICA). Current practice guidelines recommend screening to rule out significant proximal lesions. Computed tomography angiography (CTA) is currently used in the preprocedure planning of TAVR.

Purpose

This study sought to investigate the efficacy of CTA imaging in assessing the proximal coronary arteries, and the feasibility of its use as a screening tool for significant CAD before TAVR.

Methods

We retrospectively analyzed patients referred for TAVR in a single center. Patients with a preprocedure CTA, preprocedure ICA, and without prior proximal percutaneous intervention (PCI) were included in the study. Patients with poor CTA image quality precluding interpretation were excluded. The proximal segment of the coronary arteries was analyzed by CTA to assess for nonsignificant stenosis (0% to 49%), moderate stenosis (50% to 69%), and severe stenosis (≥70%). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR), negative LR, and Cohen Kappa statistic were analyzed.

Results

A total of 126 patients were included in the analysis: median age was 82 years (IQR 7), and 48% (n=60) of patients were male. The overall prevalence of significant proximal CAD was 9.5%. CTA evaluation revealed a sensitivity of 75%, specificity of 96%, PPV of 24%, NPV of 100%, positive LR of 19.0 (95% CI 10.5-24.4), and negative LR of 0.26 (95% CI 0.08-0.86) for detecting ≥50% stenosis. Using a ≥70% stenosis cutoff, evaluation revealed a sensitivity of 80%, specificity of 99%, PPV of 51%, NPV of 100%, positive LR of 128.8 (95% CI 38.4-432.0), and negative LR of 0.20 (95% CI 0.03-1.16). Cohen Kappa analysis indicated a fair agreement between pre-TAVR CTA and ICA (Cohen k-test 0.35, p <0.001).

Conclusion

Pre-TAVR CTA is a useful tool in screening for significant proximal CAD before TAVR and, due to its high negative predictive value, could spare patients the need for additional invasive testing before the procedure.
The use of sublingual nitroglycerin in patients with severe aortic stenosis before cardiac CT - prospective suty
Authors: Costa G , Silva A L , Ramalho R , Vieira M J , Goncalves L , Teixeira R
Published: June 2024

Introduction

Although nitrates are generally not recommended for patients with severe aortic stenosis, sublingual nitroglycerin (SLN) is widely employed in clinical practice in this population to improve coronary assessment in the planning cardiac computed tomography (CCT) conducted before transcatheter aortic valve implantation (TAVI).

Purpose

To assess the effect on systolic blood pressure (SBP) and the safety of SLN administration in severe aortic stenosis patients undergoing CCT.

Methods

Single-center, prospective, observational study. Patients with severe aortic stenosis undergoing CCT prior to TAVI from June to December 2023 were included in the analysis. Blood pressure readings were taken before and after the imaging procedure. A dosage of 0.5 mg of SLN was given to the SLN group before the exam started. The variation in SBP was evaluated between patients who received and did not receive SLN. Statistical analysis was performed using SPSS 28.0.1.1 software.

Results

A total of 113 patients were included, 52.2% female. The median age of the population was 81.9 (IQR 7) years. SLN was administered in 69.4% (n=77) of patients. The SLN group had a greater prevalence of patients on antihypertensive medications at baseline (47.4% vs. 75.6%, p=0.031).

Before the exam, the average SBP measured 136 (±25) mmHg, notably higher in the SLN group compared to the control (142 vs. 123 mmHg, p<0.001). Following the exam, the mean SBP dropped to 123 (±18) mmHg, although the SLN group maintained a significantly elevated SBP level when compared with the non-SLN group (128 vs. 116 mmHg, p=0.021). The overall mean variation in SBP was -10.1 (±20.9) mmHg, with the SLN group showing a significantly higher decrease in SBP (-17.4 ± 19.3 mmHg) than the non-SLN group (-1.9 ± 20.0 mmHg; p=0.009). Despite a substantial drop in SBP within the SLN group, only two patients experienced post-exam SBP levels below 100 mmHg, whereas one case was identified in the non-SLN group, with no statistically significant difference between the two groups (p=0.568). In addition, no occurrences of symptomatic hypotension were documented.

Conclusion

In this study, SLN administration before CCT led to a considerable reduction in SBP among severe aortic stenosis patients. However, this variation did not hold clinical significance, suggesting that, under careful supervision and when clinically justified, administering SLN to severe aortic stenosis patients may be considered appropriate.
Applying machine learning to diagnose obstructive coronary artery disease using calcium scoring, coronary CT angiography, and clinical data
Authors: Valk J G , Hiemstra P H , Van Dijk J D , Van Dalen J A , Slart R H J A , Tan C O , Mouden M , Vendel B N
Published: June 2024

Introduction

Traditional diagnostic risk assessment in patients undergoing CT-based calcium scoring (CACS) and coronary CT angiography (CCTA) is based on a limited number of clinical and imaging findings. Machine learning has demonstrated its suitability to use a greater number of features to model complex non-linear relations leading to a more accurate diagnostic performance. Our aim was to develop and validate a machine learning model to diagnose obstructive coronary artery disease (oCAD) in patients without prior history of CAD, using CACS, CCTA and clinical data.

Methods

We retrospectively included 1254 patients without a prior history of CAD who underwent CACS and CCTA. Cardiac risk factors; smoking, hypertension, hypercholesterolemia, diabetes, family history of CAD; age; gender; body mass index; creatinine serum values; CCTA-outcomes, CACS and medication usage were registered at time of the scan. The entire dataset was split 4:1 into a training and test dataset, respectively. A XGBboost model was developed on the training set using fivefold stratified cross-validation and hyperparameter tuning. The test dataset was used to compare the diagnostic performance of the model to the performance of expert readers, looking at specificity, sensitivity, and ROC-analysis. The primary endpoint was oCAD on invasive coronary angiographies (ICA). Patients who were not referred for ICA were presumed not to have oCAD.

Results

A total of 85 (6.8%) of the 1254 patients (46% male, 60 ± 8 years of age) were diagnosed with oCAD. Age, total calcium score, body mass index, left anterior descending artery calcium score, and creatinine serum level were the highest-ranking features to predict oCAD. The performance of the XGBoost model did not differ from expert readers in predicting oCAD (p=0.84). The model and expert readers achieved a specificity of 0.97 vs 0.95, sensitivity of 0.71 vs 1.00, and an AUC of 0.96 vs 0.97, respectively.

Conclusion

The XGBoost model demonstrated a diagnostic performance comparable to that of expert readers. Features with negative predictive value in the diagnosis of oCAD were most valuable to the model such as high CACS. Currently, the model cannot replace expert readers, but it can contribute to the consistency of oCAD diagnoses and can be used to assist physician experts.Feature importance of the XGBoost model  ROC Curve of the XGBoost model