Heart Work Research Articles

Filozofia, religia i poezja w poszukiwaniu nieskończoności

Man in contemporary culture thinks about the finite by starting from the finite (M. Foucault). The loss of reference to the infinite is not only the dominance of the naturalistic worldview, which rejects the possibility of any transcendent dimensions of the world. It is also a profound change in the areas of life that form the basis of our existence. They all tune in, so to speak, to the „man without infinity.” Historically, it has been common for us to move away from the present towards “more” and “different.” The desire for such infinity was also at the heart of cultural work. The lecture seeks to answer two questions: what happens when we lose the ability to consider infinity as a condition of the possibility of our experience? And: do philosophy, religion, and poetry still liberate us from the danger of finitude?

Development of a user‐friendly automatic ground‐based imaging platform for precise estimation of plant phenotypes in field crops

AbstractPlant phenotyping is the science to quantify the quality, photosynthesis, development, growth, and biomass productivity of different crop plants. In the past, plant phenotyping employed methods such as grid count and regression models. However, the grid count method proved to be labor‐intensive and time‐consuming, while the regression model lacked accuracy in calculating leaf area. To address these challenges, a portable automatic platform was developed for precise ground‐based imaging of field plots. This platform consisted of a frame, an RGB camera, a stepper motor, a control board, and a battery. The RGB camera captured images, which were then processed using MATLAB software. Statistical analysis was performed to compare the results obtained from the grid count, regression model, and image processing techniques. The correlation coefficient (r) between the image processing technique and the regression model for sunflower was found to be 0.98 and 0.97, respectively, whereas for kidney bean it was 0.99 and 0.96, respectively. The minimum and maximum values for leaf area density (LAD) of all selected sunflower leaves were determined to be 0.132 and 0.714 m²/m³, respectively. For kidney bean leaves, the minimum and maximum mean LAD values were found to be 0.081 and 0.239 m²/m³, respectively. Ergonomic aspects of the developed automatic system were studied. The developed system had lower physiological parameters, such as working heart rate of 99 beats/min, work pulse of 18 beats/min, oxygen consumption of 786 mL/min, and energy consumption of 11.5 kJ/min compared to the grid count method. Thus, developed automatic ground‐based imaging system would significantly reduce physiological workload and associated hazards. Therefore, the developed method proved satisfactory in comparison to other techniques, offering a quick, efficient, and user‐friendly approach for determining plant phenotypes.

Psychosocial Stressors at Work and Coronary Heart Disease Risk in Men and Women: 18-Year Prospective Cohort Study of Combined Exposures.

Psychosocial stressors at work, like job strain and effort-reward imbalance (ERI), can increase coronary heart disease (CHD) risk. ERI indicates an imbalance between the effort and received rewards. Evidence about the adverse effect of combined exposure to these work stressors on CHD risk is scarce. This study examines the separate and combined effect of job strain and ERI exposure on CHD incidence in a prospective cohort of white-collar workers in Quebec, Canada. Six thousand four hundred sixty-five white-collar workers without cardiovascular disease (mean age, 45.3±6.7) were followed for 18 years (from 2000 to 2018). Job strain and ERI were measured with validated questionnaires. CHD events were retrieved from medico-administrative databases using validated algorithms. Marginal Cox models were used to calculate hazard ratios (HR) stratified by sex. Multiple imputation and inverse probability weights were applied to minimize potential threats to internal validity. Among 3118 men, 571 had a first CHD event. Exposure to either job strain or ERI was associated with an adjusted 49% CHD risk increase (HR, 1.49 [95% CI, 1.07-2.09]). Combined exposure to job strain and ERI was associated with an adjusted 103% CHD risk increase (HR, 2.03 [95% CI, 1.38-2.97]). Exclusion of early CHD cases and censoring at retirement did not alter these associations. Among 3347 women, 265 had a first CHD event. Findings were inconclusive (passive job HR, 1.24 [95% CI, 0.80-1.91]; active job HR, 1.16 [95% CI, 0.70-1.94]; job strain HR, 1.08 [95% CI, 0.66-1.77]; ERI HR, 1.02 [95% CI, 0.72-1.45]). In this prospective cohort study, men exposed to job strain or ERI, separately and in combination, were at increased risk of CHD. Early interventions on these psychosocial stressors at work in men may be effective prevention strategies to reduce CHD burden. Among women, further investigation is required.

HPC Framework for Performing in Silico Trials Using a 3D Virtual Human Cardiac Population as Means to Assess Drug-Induced Arrhythmic Risk.

Following the 3 R's principles of animal research-replacement, reduction, and refinement-a high-performance computational framework was produced to generate a platform to perform human cardiac in-silico clinical trials as means to assess the pro-arrhythmic risk after the administrations of one or combination of two potentially arrhythmic drugs. The drugs assessed in this study were hydroxychloroquine and azithromycin. The framework employs electrophysiology simulations on high-resolution three-dimensional, biventricular human heart anatomies including phenotypic variabilities, so as to determine if differential QT-prolongation responds to drugs as observed clinically. These simulations also reproduce sex-specific ionic channel characteristics. The derived changes in the pseudo-electrocardiograms, calcium concentrations, as well as activation patterns within 3D geometries were evaluated for signs of induced arrhythmia. The virtual subjects could be evaluated at two different cycle lengths: at a normal heart rate and at a heart rate associated with stress as means to analyze the proarrhythmic risks after the administrations of hydroxychloroquine and azithromycin. Additionally, a series of experiments performed on reanimated swine hearts utilizing Visible Heart® methodologies in a four-chamber working heart model were performed to verify the arrhythmic behaviors observed in the in silico trials.The obtained results indicated similar pro-arrhythmic risk assessments within the virtual population as compared to published clinical trials (21% clinical risk vs 21.8% in silico trial risk). Evidence of transmurally heterogeneous action potential prolongations after providing a large dose of hydroxychloroquine was found as the observed mechanisms for elicited arrhythmias, both in the in vitro and the in silico models. The proposed workflow for in silico clinical drug cardiotoxicity trials allows for reproducing the complex behavior of cardiac electrophysiology in a varied population, in a matter of a few days as compared to themonths or years it requires for most in vivo human clinical trials. Importantly, our results provided evidence of the common phenotype variants that produce distinct drug-induced arrhythmogenic outcomes.

The Visual Luxury Consumer: Louis Vuitton, Hermès, Maison Schiaparelli

The luxury consumer is one of the most celebrated concepts in what is known as luxury brand management. However, this study of the associations between the visual, luxury, and the consumer offers new possibilities for thinking about the contemporary visual culture of luxury brands such as Louis Vuitton, Hermès, and Maison Schiaparelli. The article guides readers through issues at the heart of work on the luxury consumer, including the visual luxury consumer as practitioner, as an expert who uses their visual knowledge as part of their luxury consumption. What becomes apparent is that work on the luxury consumer is impossible to ignore for anybody who is serious about contemporary visual culture, and this investigation provides an ideal critical introduction to a wide variety of texts and topics related to luxury and consumption.

Depending on Hadith in Abu Bakr Al-Anbari's Book: The Masculine and Feminine

This research is an attempt to highlight the attitude of the Kufian linguists todepending on the Prophet's Hadith, and to show how they use it in reasoningwhat they want to highlight and win. The research sheds light on animportant issue, namely the return of the Kufi language to the Prophet'sHadith and the Prophet's Without verifying what is relevant to his presence,and whether this issue is at the heart of the linguistic work or not.

Cry: the vitalising intelligence in our sounding

This article illustrates the vocal heritage of our rich evolutionary unfolding which we share with multiple species across a continuum of calls and responses. It highlights listening as a felt sense, mediated by all bodily structures, that sits at the heart of therapeutic work. It considers the vitalising nature of sounding, and the consequences of losing touch with this innate capacity. Finally, it warns that noise pollution is one of many factors disconnecting us from our core sense of who we are and impinging on all animal life.

Becoming processual: Time to de-place managerial education

Managerial education and managerial research are still deeply emplaced and emplacing phenomena. They are expected to be emplaced somewhere, in bounded space-times and in the powerful subjectivities of students and colleagues, awaiting their expression and expansion. This constitutes a strange extensive continuum which remains the heart of academic work. In this provocative essay, we invite organization scholars to de-place managerial phenomena and to become processual. We use one-block auto-ethnographic vignettes to show that existentiality matters and can lead to different life paths, in particular processual ones. In a final discussion, we offer a manifesto for those interested in cultivating processuality in their work as teachers and academics.

Safeguarding the unknown: performance measurement, academic agency and the meaning of research quality in practice

PurposeThe authors examine how performance measurement systems (PMSs) and academic agency influence the meaning of research quality in practice. The worries are that the notion of research quality is becoming too simplistically and narrowly determined by research quality's measurable proxies and that academics, especially manager-academics, do not sufficiently realise this risk. Whilst prior literature has covered the effects of performance measurement in the university sector broadly and how PMSs are mobilised locally, there is only little understanding of whether and how PMSs affect the meaning of research quality in practice.Design/methodology/approachThe study is designed as a comparative case study of two university faculties in Finland. The role of conceptual analysis plays a notable role in the study, too.FindingsThe authors find that manager-academics of the two examined faculties have rather similar conceptual understandings of research quality. However, there were differences in the degree of slippage between the “espoused-meaning” of research quality and “meaning-in-practice” of research quality. The authors traced these differences to how the local PMS and manager-academics’ agency relate to one another within the context of increasing global and national performance pressures. The authors developed a tentative framework for the various “styles of agency”. This suggests how the relationship between the local PMS and manager-academics’ exerted agency shapes the “degrees of freedom” of the meaning of research quality in practice.Originality/valueGiven that research quality lies at the heart of academic work, the authors' paper indicates that exploring the three matters – performance measurement, the agency of manager-academics and the meaning of research quality in practice – in combination is crucial for the sustainability of the academe. The authors contribute to the literature by detailing the way in which local PMS and manager-academics' agency have material impacts on what research quality means in practice. The authors conclude by highlighting the pressing need for manager-academics to exercise the agency in efforts to safeguard a broad and pluralistic understanding of research quality in practice.

Myocardial work and left heart strain variation according to different grades of mitral regurgitation severity and symptoms

Abstract Funding Acknowledgements Type of funding sources: None. Background Myocardial work (MW) estimation by pressure-strain loops using an implemented speckle tracking software has showed to estimate LV contractile properties overcoming the load-dependency limit of left ventricular (LV) global longitudinal strain (GLS). This has proved useful particularly in clinical setting characterized by frequent hemodynamic variations, such as heart failure and valvular heart disease. However, the variation of MW parameters across different stages of mitral regurgitation (MR) and its impact on symptoms has never been investigated. Objective The aim of this observational study was to assess the variations of MW and deformation parameters of left heart chambers in mild, moderate and severe MR. Methods Consecutive patients with mild, moderate and severe MR were prospectively enrolled. Exclusion criteria were: chronic atrial fibrillation, valvular heart prosthesis, previous cardiac surgery. Clinical evaluation, blood sample tests, ECG and echocardiography were performed. Speckle tracking analysis completed by myocardial work were performed offline. Patients were then divided into groups first according to MR severity. Differences among the groups were analyzed by student T test (or non-parametric tests for non-normally distributed variables) and predictors of symptoms (as NYHA class ≥ 2) were explored by logistic regression analysis. Results Overall, 120 patients were enrolled (40 mild, 40 moderate, 40 severe MR). LV GLS improved according to severity, while Global PALS reduced according to MR severity. Global constructive work (GCW) and global wasted work (GWW) significantly improved in patients with moderate and severe MR, while global work efficiency (GWE) showed a trend towards reduction in patients with higher grades of MR. Global work index did not change significantly in the three groups (Fig.1). Among strain parameters, global PALS emerged as a predictor of NYHA class (R2=0.2, p<0.001) These results are explained by the pathophysiology of MR, characterized by a mechanism of attempted LV compensation to volume overload with increased contractility parallel to the disease progress, although with low efficacy on increasing LV stroke volume and increased wasted work; while LA and diastolic function have an early reduction which is associated with the occurrence of symptoms. Conclusions Myocardial deformation parameters of the left heart chambers accurately reflect the pathophysiologic mechanisms of MR stages and are associate with the burden of symptoms.

Heart rate responses in critical care trainees during airway intubation: a comparison between the simulated and clinical environments

ObjectiveThis study aimed to compare the heart rate response to stress during airway intubations in clinical practice and a simulated environment.MethodsTwenty-five critical care registrars participated in the study over a 3-month period. Heart rate data during intubations was recorded by a FitBit® Charge 2 worn by each participant during their clinical practice, and during a single simulated airway management scenario. The heart rate range was calculated by subtracting the baseline working heart rate (BWHR) from the maximum functional heart rate (MFHR). For each airway intubation performed participants recorded an airway diary entry. Data from intubations performed in the clinical environment was compared to data from a simulated environment. Heart rate changes were observed in two ways: percentage rise (median) across the 20-min intubation period and; percentage rise at point of intubation (median).ResultsEighteen critical care registrars completed the study, mean age 31.8 years (SD = 2.015, 95% CI = 30.85–32.71). Throughout the 20-min peri-intubation recording period there was no significant difference in the median change in heart rates between the clinical (14.72%) and simulation (15.96%) environment (p = 0.149). At the point of intubation there was no significant difference in the median change in heart rate between the clinical (16.03%) and the simulation (25.65%) environment groups (p = 0.054).ConclusionIn this small population of critical care trainees, a simulation scenario induced a comparable heart rate response to the clinical environment during intubation. This provides evidence that simulation scenarios are able to induce a comparable physiological stress response to the clinical environment and thus facilitates effective teaching of a high-risk procedure in a safe manner.

32 Exercise versus feed restriction: What is the most efficient weight loss option for your fat horse?

In first world countries, 45–75% of domesticated horses are considered overweight. Accumulation of excessive fat mass puts horses at risk for co-morbidities such as systemic inflammation and osteoarthritis. The objective was to characterize weight loss in overweight horses during 10 weeks of feed restriction, exercise, or both. Thirty-two horses, 4 geldings and 28 mares, mean age of 14 ± 4, with a body condition score (BCS) of at least 7/9, were fed controlled, individualized hay feedings 3 times a day with a concentrate meal. Diets were based on horse's body weight (BW) (kg) and calculated using FeedXL. Horses were randomly allocated into one of 4 treatment groups, Daily Exercise (E), Feed Restriction (FR), Feed Restriction & Daily Exercise (FRE), or unrestricted sedentary Control (C). The C and E horses were fed 100% of their Digestible Energy (DE) requirements, while FR and FRE horses were fed 85%. The E and FRE groups underwent submaximal unridden exercise, with a consistent working heart rate of 150 bpm, for 20 min, 5 times a week, with a walking warm-up and cooldown, with the approximate DE loss of 15% based on the NRC. In wk 1, 5 and 10, morphometric measurements were recorded, including BW (kg, via weight tape), cresty neck score (CN) (/5), whole body BCS (/9) and individual BCS (/9) for 8 different anatomical locations. Original mean BCS for all treatment groups was 7 ±0.2. Original BW (kg) for each of the treatment groups are as follows: C 486 ± 11, E 501 ± 11, FR 485 ± 12, and FRE 469 ± 11. Statistical analysis was performed using SAS Studio. Data were analyzed using 1-Way RM ANOVA for individual treatments and 2-Way RM ANOVA to determine significant (P ≤ 0.05) effects of and interactions between time and treatment. There was a reduction in BW across time for all groups (P < 0.0001). The mean weight loss (kg) for each treatment group are as follows: C 28kg, E 31kg, FR 27kg, FRE 36kg. The CN score was reduced in E and FRE horses (P = 0.01; P = 0.02). Whole body BCS was reduced in E (P < 0.0001), FR (P = 0.001) and FRE (P < 0.0001). Treatment group affected anatomical BCS of the tailhead and shoulder (P = 0.05 and P = 0.01), with FRE having the greatest reduction (P = 0.0005 and P = 0.001,). Anatomical BCS loss at the withers was found to have an interaction between time and treatment (P = 0.02). In conclusion, although all horses lost BW, there were differences in how the treatment groups lost fat mass, with exercise programs having a significant effect on the change in CN, tailhead and shoulder fat mass. Therefore, the most efficient weight loss program, is that of combining both daily exercise and feed restriction.

Manual Shelling of Preconditioned Cashew Nut Using Handtool and Its Impact on Occupational Health of Workers

India is the second-leading country in production of cashew nut. Cashew nut are roasted or steamed before shelling. The study was conducted in cashew nut processing industries situated in Selsella and Mankachar blocks of Meghalaya and Assam. The purpose of this study was to compare the cutting strength of cashew nut shells influenced by roasting and steaming. The impact of manual shelling of cashew nut on occupational health of workers was also assessed by using ergonomic tools. The moisture content, colour, and hardness of cashew nut shell were measured. The processing of cashew nut influenced the cutting strength of cashew nut significantly. Steamed cashew nut shell was stronger than the roasted cashew nut shell. Hence, manually shelling of steamed cashew nut shell required more force compared to with that of roasted cashew nut shell. Four cashew nut processing industries, two each from Selsella and Mankachar block of Meghalaya and Assam, respectively were selected purposively. A group of 10 female workers from each industry were selected randomly as sample for this study. Ergonomic parameters: working Heart Rate, energy expenditure, rated perceived exertion, hand grip measurements, RULA and REBA analysis were used to assess occupational health of workers. The results of the study showed that the workers of cashew nut industries were exposed to high occupational health and safety risk due to poor working environment, awkward working posture, repetitive and tedious job.

Development of an automated mobile robotic sprayer to prevent workers' exposure of agro‐chemicals inside polyhouse

AbstractAutomated spraying practices are inevitable for modern polyhouse management to attain a broader objective of minimizing human exposure to agrochemicals. In the present study, an automated mobile robotic sprayer (AMRS) was developed to combat the increased human intervention and safeguard agricultural workers from potential health hazards. The system mainly comprises embedded sensors (ultrasonic, proximity, XBee) and controllers (Arduino, PLC). The controller drives the system on a piping track between the rows as well as on the head space achieving end‐to‐end automation for spraying operations. The system performance was evaluated on the tomato crop with respect to the physiological traits, yield and economics. Additionally, the study leveraged response surface methodology to optimize forward speed, spray distance, and working pressure of AMRS on the responses, droplet density, coverage, volume mean diameter (VMD) and application rate. Optimization of forward speed (0.79 km/h), spray distance (250 mm) and working pressure (0.40 MPa) resulted in 90.7 droplets/cm2 droplet density, 47.1% coverage, 170.2 μm VMD and 86.0 mL/m2 of application rate. Ergonomic aspects of AMRS were assessed by the parameters, human exposure, discomfort and postural assessment with respect to knapsack sprayer. The working heart rate of 103 beats/min, work pulse of 12 beats/min, oxygen consumption rate of 916 mL/min and energy expenditure rate of 18.7 kJ/min recorded during the ergonomic evaluation of the AMRS were 25%, 75%, 42%, and 41% lower compared to manual spraying, respectively. Moreover, three–six times higher work pulse, cardiac cost, body part discomfort score and overall discomfort rating were observed which indicated more drudgery involved in manual spraying. State‐of‐the‐art system developed for polyhouses would minimize the drudgery and health hazards, significantly. The system's resilience and effectiveness pave the way for its wider deployment where the use of agrochemicals are prevalent, particularly in small‐size polyhouses.

Reflecting: Two Decades of portal Editorials and Accomplishments

Reflecting:Two Decades of portal Editorials and Accomplishments Ellysa Stern Cahoy (bio) As portal's new editor (as of January 2023), I am finding inspiration in reflection as I excavate our journal's rich history to uncover future possibilities. Reading portal's past editorials (published in each issue since the journal's inception in 2001) is a fascinating way to better understand not only portal's successful trajectory over the past two-plus decades, but also the issues and challenges our profession as a whole has faced and largely conquered. Widely recognized as the father of reflective practice, the philosopher and educator John Dewey wrote, "Reflective thinking is always more or less troublesome because it involves overcoming the inertia that inclines one to accept suggestions at their face value; it involves willingness to endure a condition of mental unrest."1 A more recent researcher on the power of reflection, Carol Rodgers, defined the act of reflection itself as "a meaning-making process that moves a learner from one experience into the next with deeper understanding of its relationships with and connections to other experiences and ideas." She asserts that reflection should happen in interaction with others and that it requires an attitude attuned to personal and professional growth and change.2 The "mental unrest" and "meaning making" that Dewey and Rodgers describe is at the heart of all academic work. With engaged students, learning is almost always uncomfortable, because it involves internal challenge and personal growth. The act of reflection, a partner in the learning process, is ideally incorporated throughout all phases of a creative, intellectual process, including the production of scholarly work. As I explored two decades of portal editorials, I saw multiple instances of reflection and "meaning making"—librarians confronting tough issues in our profession and looking toward creative solutions, as well as the "mental unrest" that comes when one is within a problem and the solution, while ahead, is not yet in sight. Our journal's first editorial, "Through portal," written by inaugural managing editor Gloriana St. Clair, does not mention the "mental unrest" and the coalescing event behind portal's founding—the 1999 purchase of the Journal of Academic Librarianship's publisher by Elsevier, resulting in higher subscription costs and an imperative for LIS [End Page 223] researchers to assume leadership in scholarly publishing.3 She does, however, identify three core objectives for the nascent publication: • To offer an affordable alternative to serials that have gone up an average of 9 percent a year while the consumer price index increased only 3.3 percent; • To provide a more inviting, constructive, and productive environment for authors; • To model a scholarly communications system as outlined in recent pronouncements from the Association of American Universities (AAU) and the Create Change initiative.4 These imperatives persist today. EBSCO's recently released 2022 Serials Price Projection Report indicates that for research and academic libraries, journal prices have increased more than 18 percent over the past four years (2018–2022).5 Open access research publishing is growing and provides alternatives, but deep challenges remain. St. Clair also discusses her initiation of portal's mentoring program, which was originally designed to provide intensive support from "the moment (authors) decide to engage in research to the moment when they elect to submit the finished product either to portal or to some other journal."6 Individual mentoring was provided by seasoned librarians active in the American Library Association's Library Administration and Management Association Research Committee and the Library Research Round Table. Executive editor Charles Lowry, also a portal founding editor, described the impact of the mentoring program in 2004 as "advanc(ing) a new idea that a manuscript may be raw, but if it contains the core of good research the author deserves more than a rejection. Thus we extend mentoring to help develop good ideas and good research into viable publishable articles."7 portal's mentoring program flourishes to the present day in the form of our Editorial Board's double-blind peer review of refereed articles. When an article is submitted to portal for peer-reviewed consideration, the conversation begins. Each reviewer provides unique and developmental feedback on an article under consideration...

Effects of hyperprotein diet on anxiety, haemodynamics and morphofunctional aspects of the heart of Wistar rats.

What is the central question of this study? The consumption of a high-protein diet has been associated with an anxiogenic factor that can influence anxiety and possible cardiovascular changes: does the consumption of a high-protein diet interfere with anxiety, haemodynamics and morphofunctional aspects of the heart of Wistar rats? What is the main finding and its importance? Our study showed that the high-protein diet did not interfere with anxiety and haemodynamics. The animals in the hyperproteic group showed positive heart adaptations characterized by less work and lower heart rate without impairing ejection fraction and systemic blood pressure. Anxiety is a mechanism preparatory to a response in situations of threat and danger, involving behavioural, affective and physiological factors. Protein-based foods have a high concentration of amino acids which perform multiple functions, including in the biosynthesis of excitatory transmitters for the central nervous system. In recent years, adherence to high-protein diets has been gaining ground in society, on the basis that it brings benefits to the musculoskeletal system and cardiovascular health. The aim of the present study was to investigate the effect of a high-protein diet in a state of anxiety and to investigate morphofunctional cardiovascular effects of a high-protein diet in Wistar rats. The experiment lasted 8weeks and two groups of male rats were submitted to either a normoproteic or a hyperproteic diet. Anxiety was assessed using the plus maze test and cardiovascular morphofunctional aspects using transthoracic echocardiography and invasive measurements of femoral blood pressure. There was no statistically significant difference in the anxiety test, but the hyperproteic group was more agitated, with greater displacement during the test. Changes were found in systolic and end-diastolic volume, left ventricular diameter in systole and heart rate, which were significantly lower in the hyperproteic group, and there was an increase in the thickness of the interventricular septum in diastole. The results showed no influence of the higher protein diet on the animals' anxiety, body weight and haemodynamics.

N-terminal truncated cardiac troponin I enhances Frank-Starling response by increasing myofilament sensitivity to resting tension.

Cardiac troponin I (cTnI) of higher vertebrates has evolved with an N-terminal extension, of which deletion via restrictive proteolysis occurs as a compensatory adaptation in chronic heart failure to increase ventricular relaxation and stroke volume. Here, we demonstrate in a transgenic mouse model expressing solely N-terminal truncated cTnI (cTnI-ND) in the heart with deletion of the endogenous cTnI gene. Functional studies using ex vivo working hearts showed an extended Frank-Starling response to preload with reduced left ventricular end diastolic pressure. The enhanced Frank-Starling response effectively increases systolic ventricular pressure development and stroke volume. A novel finding is that cTnI-ND increases left ventricular relaxation velocity and stroke volume without increasing the end diastolic volume. Consistently, the optimal resting sarcomere length (SL) for maximum force development in cTnI-ND cardiac muscle was not different from wild-type (WT) control. Despite the removal of the protein kinase A (PKA) phosphorylation sites in cTnI, β-adrenergic stimulation remains effective on augmenting the enhanced Frank-Starling response of cTnI-ND hearts. Force-pCa relationship studies using skinned preparations found that while cTnI-ND cardiac muscle shows a resting SL-resting tension relationship similar to WT control, cTnI-ND significantly increases myofibril Ca2+ sensitivity to resting tension. The results demonstrate that restrictive N-terminal deletion of cTnI enhances Frank-Starling response by increasing myofilament sensitivity to resting tension rather than directly depending on SL. This novel function of cTnI regulation suggests a myofilament approach to utilizing Frank-Starling mechanism for the treatment of heart failure, especially diastolic failure where ventricular filling is limited.

Looking at the Bigger Picture with Hulya Kirkici

At the heart of all Hulya Kirkici's work is a commitment to solving humanity's problems. This was instilled in her by her family at a very young age and has grounded her throughout a career of pioneering research in electrical insulation of aerospace and space power systems, lasers, plasma physics, and beyond. Long before becoming a PhD, IEEE Fellow, Eric 0. Forster Distinguished Service Award recipient (and many more accolades), she was a little girl fascinated by numbers.

Mild hypothermia attenuates ischaemia/reperfusion injury: insights from serial non-invasive pressure-volume loops.

Mild hypothermia, 32-35°C, reduces infarct size in experimental studies, potentially mediating reperfusion injuries, but human trials have been ambiguous. To elucidate the cardioprotective mechanisms of mild hypothermia, we analysed cardiac performance in a porcine model of ischaemia/reperfusion, with serial cardiovascular magnetic resonance (CMR) imaging throughout 1 week using non-invasive pressure-volume (PV) loops. Normothermia and Hypothermia group sessions (n = 7 + 7 pigs, non-random allocation) were imaged with Cardiovascular magnetic resonance (CMR) at baseline and subjected to 40 min of normothermic ischaemia by catheter intervention. Thereafter, the Hypothermia group was rapidly cooled (mean 34.5°C) for 5 min before reperfusion. Additional CMR sessions at 2 h, 24 h, and 7 days acquired ventricular volumes and ischaemic injuries (unblinded analysis). Stroke volume (SV: -24%; P = 0.029; Friedmans test) and ejection fraction (EF: -20%; P = 0.068) were notably reduced at 24 h in the Normothermia group compared with baseline. In contrast, the decreases were ameliorated in the Hypothermia group (SV: -6%; P = 0.77; EF: -6%; P = 0.13). Mean arterial pressure remained stable in Normothermic animals (-3%, P = 0.77) but dropped 2 h post-reperfusion in hypothermic animals (-18%, P = 0.007). Both groups experienced a decrease and partial recovery pattern for PV loop-derived variables over 1 week, but the adverse effects tended to attenuate in the Hypothermia group. Infarct sizes were 10 ± 8% in Hypothermic and 15 ± 8% in Normothermic animals (P = 0.32). Analysis of covariance at 24 h indicated that hypothermia has cardioprotective properties incremental to reducing infarct size, such as higher external power (P = 0.061) and lower arterial elastance (P = 0.015). Using non-invasive PV loops by CMR, we observed that mild hypothermia at reperfusion alleviates the heart's work after ischaemia/reperfusion injuries during the first week and preserves short-term cardiac performance. This hypothesis-generating study suggests hypothermia to have cardioprotective properties, incremental to reducing infarct size. The primary cardioprotective mechanism was likely an afterload reduction acutely unloading the left ventricle.

A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic.

The lifestyles change of children and adolescents during the COVID-19 pandemic due to antipandemic measures can affect their sleep health. Existing studies have used convenient samples and focused on the initial months of the pandemic, leaving a knowledge gap on changes in young people's sleep patterns under the "new normal" under COVID-19. As part of a territory-wide epidemiological study in Hong Kong, this cross-sectional study recruited primary and secondary school students by stratified random sampling. Sleep parameters were collected using the structured diagnostic interview for sleep patterns and disorders. We investigated the pandemic's effects on sleep parameters by comparing data of participants recruited pre-COVID and those recruited during COVID using multivariate regression, adjusting for age, sex, household income, seasonality, and presence of mental disorders, and the moderators and mediators of the effects. Between September 1, 2019 and June 2, 2021, 791 primary and 442 secondary school students were recruited and analyzed. Primary school and secondary school participants assessed before COVID had a longer sleep latency on school days (95% confidence interval [CI] = 1.0-5.2 minutes, adjusted P-value = .010; and 95% CI= 3.9-13.0 minutes, adjusted P-value = .004, respectively) and nonschool days (95% CI = 1.7-7.2 minutes, adjusted P-value = .005; 95% CI = 3.4-13.7 minutes, adjusted P-value = .014, respectively). Low household income was a moderator for later bedtime (adjusted P-value = .032) and later sleep onset (adjusted P-value = .043) during nonschool days among secondary school students. Changes associated with COVID have a widespread and enduring effect on the sleep health of school-aged students in Hong Kong. Household income plays a role in adolescent sleep health resilience, and the impact of antiepidemic measures on the health gaps of the youth should be considered. Chau SWH, Hussain S, Chan SSM, etal. A comparison of sleep-wake patterns among school-age children and adolescents in Hong Kong before and during the COVID-19 pandemic. J Clin Sleep Med. 2023;19(4):749-757.