Mismatch Negativity (MMN) and Late Discriminative Negativity (LDN) event related potentials are objective indicators of auditory discrimination. The aim of the study was to determine the test-retest reliability of MMN and LDN recorded to simple speech contrasts in children with listening difficulties. MMN and LDN responses were recorded from Fz and Cz electrodes for a /da/-/ga/ contrast twice within a 10-day period. Intraclass Correlation coefficients (ICC) were used to determine test-retest reliability of MMN and LDN. Eight five children (55 males, aged 7.0-12.8 years) with listening difficulties participated in this research. Children were grouped into four clusters based on their reading, language, nonverbal intelligence, and cognitive skills such that children within each cluster had similar profiles of strengths and difficulties. ICC for MMN were better than LDN. Results showed that MMN amplitude did not differ between visits, but LDN amplitude reduced significantly (more positive peak amplitude) at visit 2 compared to visit 1. At visit 1, MMN and LDN were detectable in only 41%/42% and 18%/21% (Fz/Cz) of participants respectively. MMN was most replicable (71%) for children with listening difficulties in the cluster with relatively good nonverbal intelligence and language skills. The results do not support the clinical utility of LDN for objective assessment of auditory discrimination. Although MMN had better test-retest reliability, overall detectability was poor; improved detectability is needed for MMN to have robust clinical utility in children.

Understanding the drivers of spatially and temporally correlated (synchronous) fluctuations in abundance is a fundamental challenge in ecology and conservation. Synchronous fluctuations in different demographic rates can potentially drive or dampen abundance synchrony, but demographic synchrony is generally poorly understood. Using long-term count and demographic data for breeding land-birds at sites across Europe, we show that the strength and scale of synchrony are greatest in productivity, followed by adult survival rates and then counts. However, count fluctuations are more synchronous with survival than with productivity. Despite migratory and resident species having similar periodicities of count synchrony, synchrony in both demographic rates was more common over long-timescales in resident species and short-timescales in migrant species. These findings suggest local impacts of synchronous fluctuations in adult survival rates on count synchrony, potentially dampening effects of large-scale synchrony in productivity, and that the environmental drivers of synchrony may differ between residents and migrants.

Atypical Hemolytic Uremic Syndrome Triggered by COVID-19 Infection in a Pediatric Patient with CD46 MutationParisa Maleki Dana1, Parsa Lorestani2, Mohamad Reza Tohidi3

Objectives: This study presents findings captured in the first 1.5 years of the Virus Monitoring in Denmark (VMD) surveillance system. It describes trends in respiratory viruses, related symptoms, and participant demographics and behaviors. Methods: VMD used self-swabbing and self-reported symptoms to monitor respiratory viruses in the general population. Participants were recruited via digital invitations to a representative sample of the population or through workplaces. Symptomatic participants could self-swab and register their samples and report their symptoms via a dedicated smartphone web app. Results: With 30,627 participants and 12,642 samples analyzed, VMD had broad demographic representation. SARS-CoV-2 was the most frequently detected virus, with positivity rates peaking at over 50% in late 2023. Participants commonly self-swabbed because of fever, cough, and rhinorrhea with influenza A linked to the highest median number of symptoms. Participants only provided samples after reaching a specific symptom threshold and participation affected health-seeking behaviors and work attendance of few individuals. Conclusions: VMD continuously provided real-time insights into respiratory virus trends and symptomatology in the general non-healthcare seeking population. Its accessibility – available to anyone with a Danish identification number, a smartphone and an invitation – highlights its potential as a mass testing preparedness tool.

In recent decades, natural fibers reinforced composites in various applications have significantly developed. One of the critical properties of hybrid composites is their fatigue behavior, which affects the lifetime and application range of these materials, especially when the composite is drilled. This study aims to analyze the fatigue behavior of the central open-hole kenaf/glass multilayer hybrid composites. For this purpose, pure and hybrid kenaf/glass four layers composite samples with different stacking sequences, with and without a central hole were produced, and their tensile strength was evaluated. Afterward, the optimized hybrid composite (GKKG) and two pure glass (G4) and kenaf (K4) samples were analyzed under the fatigue tensile test at three stress levels. The results showed that the four layers drilled pure glass sample exhibited the highest fatigue strength, enduring 115,000 cycles at a stress level of 50%. The drilled hybrid kenaf/glass sample (GKKG) also showed outstanding fatigue strength, bearing approximately 54,000 cycles at a stress level of 50%. The slope of the stress-logarithm(N) curve of the hybrid sample was considerably smaller than the pure glass. This indicates lower sensitivity of drilled hybrid composites reinforced with natural fibers to the fatigue loading.

Background: People with cystic fibrosis (pwCF) often have multifactorial peripheral muscle abnormalities attributed to, for example, malnutrition, steroid use, altered redox balance and, potentially, CF-specific intrinsic alterations. Malnutrition in CF now includes an increasing prevalence of overweight and obesity, particularly in those treated with CF transmembrane conductance regulator (CFTR) modulators. We aimed to characterise peripheral muscle function and body composition of pwCF on Elexacaftor/Tezacaftor/Ivacaftor (ETI) CFTR modulator treatment, compared to healthy controls. Methods: Fifteen pwCF on ETI, and 15 healthy age- and sex-matched controls (CON), underwent whole-body dual-energy X-ray absorptiometry scans, and a comprehensive evaluation of peripheral muscle function. These tests included quadriceps maximal isometric force measurement, an intermittent isometric quadriceps fatiguing protocol, handgrip strength dynamometry, squat jump height assessment, and a 1-minute sit-to-stand test. Results: No differences in quadriceps maximal isometric force (CON: 181.60 ± 92.90 Nm vs. CF: 146.15 ± 52.48 Nm, P = 0.21, d = 0.47), handgrip strength (CON: 34 ± 15 kg vs. CF: 31 ± 11 kg, P = 0.62, d = 0.18), peripheral muscle endurance, fatigue, or power were observed between the groups ( P>0.05). Moreover, no differences in whole-body, trunk or limb lean mass, fat-free mass, fat mass, or whole-body bone mineral density were evident ( P>0.05). Conclusion: Comparable peripheral muscle mass and function may be achievable in pwCF on ETI, especially those with good lung function. Research is needed to confirm these improvements in pwCF who have more severe lung disease, are less physically active, and have less optimal nutrition and exercise support.

Surviving the storm: Insights into the pericardial injuries and roller coaster of multisystem trauma in bomb blast victimsMuhammad Nadeem Ahmad1, Shahzeb Ali2, Muhammad Ahmed1, Naila Nadeem1, Mallick Muhammad Zohaibuddin1, Hatem Eltaly3, Muhammad Owais Rao1, Faheemullah Khan3, Uffan Zafar11 The Aga Khan University Hospital, Karachi, Pakistan.2 Quaid-e-Azam Medical college, Bahawalpur, Punjab, Pakistan.3 Cleveland Clinic Main Campus Hospital, Cleveland, Ohio, USA .

Rationale: Sex estimation by analysis of amelogenin peptides in archaeological and fossil material has recently been gaining great traction within the fields of archaeology and palaeontology. Current widely used proteomic amelogenin sex estimation methods are hindered by relatively long mass spectrometric run times, or targeting peptides specific to human amelogenin proteins. Untargeted, high-throughput amelogenin sexing would be invaluable for a range of applications, from sex estimation of remains at mass grave sites to broadening the application of rapid amelogenin sexing to non-hominin species for husbandry and evolutionary studies. Methods: A new acid etch amelogenin analysis protocol followed by Evosep-LC-TIMS-TOF mass spectrometry is presented, providing global peptide data through rapid mass spectrometric methods in under 20 minutes per sample (including sample preparation, mass spectrometric acquisition and data processing). Furthermore, this method is applied to a preliminary study of both modern and archaeological Bos taurus remains, alongside archaeological human remains, showing the potential of straightforward application of this rapid amelogenin sexing method to a range of taxa. Results: Application of the developed Evosep-LC-TIMS-TOF mass spectrometry shows the novel acid etch approach improved peptide counts. Furthermore, rapid untargeted mass spectrometry using the Evosep-LC-TIMS-TOF gave comparable peptide counts to conventional long untargeted methods, while maintaining similar, or faster, acquisition times to those reported in methods targeting specific human amelogenin peptides. Conclusions: Rapid, untargeted Evosep-LC-TIMS-TOF mass spectrometry was successfully implemented in sex estimation of modern and archaeological material from Bos taurus and human teeth. This demonstrates an advancement in low-cost, high-throughput amelogenin sex estimation, for both human and zooarchaeological applications.

INTESTINAL PERFORATION SECONDARY TO BORTEZOMIB INDUCED AUTONOMIC NEUROPATHY

A document by Bibek Shrestha. Click on the document to view its contents.

Following the announcement by the new American administration of a pause and review of funding to international aid programmes, we comment on the potential effect on global health security and argue for increased recognition of the role of National Public Health Institutes (NPHIs) to mitigate the impacts.

In this paper, we study the time asymptotic behavior of solutions toward rarefaction wave for the impermeable wall problems of the one-dimensional isentropic compressible Navier-Stokes-Allen-Cahn system with density and phase field variable dependent viscosity on the half line R + = ( 0 , + ∞ ) , which models the motion of a mixture of two viscous compressible fluids. We consider the case when the viscosity coefficient ν ( ρ , χ ) = ρ α χ β and the pressure p ( ρ ) = ρ γ , where ρ= ρ( t,x) is the density of the fluid, χ= χ( t,x) is the phase field variable, and α,β,γ∈R are parameters. Under some suitable assumptions on the boundary data and spatial-asymptotic state of the velocity field, the time asymptotic profile of these problems is the 2-rarefaction wave of the resulting Euler system. By employing the elementary L 2 -energy method, it is shown that this 2-rarefaction wave is time-asymptotically stable provided that the parameters α,β,γ and the initial perturbation satisfy some conditions. Here the initial perturbation for the phase field variable is small, but the initial perturbation for the density and velocity of the fluid, and the strength of the rarefaction wave can be arbitrarily large.

Traditional trans-critical CO 2 refrigeration cycles are energy-intensive, and their efficiency is influenced by outdoor conditions. This study presents a novel technique to enhance the efficiency of these cycles by integrating a thermoelectric sub-cooler tailored to Jordan’s climate. The trans-critical CO 2 refrigeration cycle, with a nominal refrigeration capacity of 14 kW, was modeled using Engineering Equation Solver (EES) software. A key aspect of this study is the incorporation of solar energy through a custom-designed photovoltaic (PV) system to power the refrigeration cycle, contributing to sustainable cooling technology. Key performance indicators, including refrigeration capacity, power consumption, and coefficient of performance (COP), were thoroughly investigated across varying parameters such as gas cooler pressure (8,000–13,000 kPa), evaporation temperature (-15 to 15°C), ambient temperature (28–40°C), current supply (5–15A), and the number of thermoelectric pairs (50–150). Results showed that increasing gas cooling pressure increased refrigeration capacity by approximately 79%. At a gas cooling pressure of 9,000 kPa, the thermoelectric sub-cooler increased refrigeration capacity by 55%. Increasing the evaporation temperature improved the COP by approximately 125% and reduced power consumption by 67%. At an evaporation temperature of -15°C, the thermoelectric sub-cooler improved performance by 7.5%. Lowering the ambient temperature also enhanced COP by 60% and reduced power consumption by 33%. At a 40°C ambient temperature, the sub-cooler improved COP by 7.6%. Experimental validation showed a 6% average deviation between simulation and experimental results for COP. The on-grid PV system designed with PVsyst software successfully met the cycle’s energy demands, achieving 45.3% energy savings.

Abstract Objectives: Women experiencing reduced fetal movements (RFM) have an increased risk of adverse pregnancy outcome (APO). Single-population studies may introduce bias and limiting generalisability. This study aimed to identify factors most strongly associated with APO, including stillbirth, fetal growth restriction (FGR), and admission to neonatal intensive care unit in women with RFM. Design and settings: Individual-level data from multiple sites in Manchester and Leicester were synthesised and analysed. Population or Sample: 1,175 women between 28 +0 and 41 +0 weeks’ gestation with singleton pregnancies. Methods: Factors associated with APO were assessed by two-stage individual participant data meta-analysis (IPD-MA). Main Results: 7.7% of RFM pregnancies ended in APO, with the most common complication being FGR (birthweight ≤3 rd centile) in 4.6%. Maternal past medical history (adjusted Odds Ratio, aOR = 2.28, 95% CI 1.08-4.83) and smoking status (aOR = 2.52, 95% CI 1.20-5.29) were most strongly associated with APO. Estimated fetal weight (EFW) percentile (aOR = 0.97, 95% CI 0.96-0.99) and maternal age (aOR = 1.05, 95% CI 1.01-1.09) were also significant risk factors, though high heterogeneity between studies in EFW percentile was observed (I 2 = 76.84%, Tau 2 = 0.0004, Q-statistic p-value = 0.0007). Conclusions: IPD-MA allowed amalgamation of patient-level data across studies, and more accurate and reliable associations were found by accounting for heterogeneity. Further work is required to investigate the model’s generalisability across diverse populations and settings. Funding: This study received no specific funding. Keywords: Individual Participant Data Meta-Analysis; Adverse pregnancy outcome; Stillbirth; Fetal Growth Restriction; Perinatal mortality; Decreased Fetal Movement

INTRODUCTIONInternal hernias are primarily caused by the intestine stretching through a mesenteric defect or peritoneum defect (1). They could be acquired or congenital. A rare congenital defect called a para duodenal hernia (PDH) is caused by a malrotation of the midgut (2). PDHs make up 53% of all internal hernias, making them the most frequent type (3). Because of the variability of the clinical signs, PDHs are challenging to identify (4). PDH may start as acute blockage or recurrent abdominal pain symptoms (43%), or it may remain asymptomatic for the duration of the patient’s life. Of all internal hernias, between 10 and 50 percent are found after unrelated abdominal surgeries, imaging tests, or autopsies (5). An abdominal computed tomography scan performed before surgery is typically diagnostic, yet Frequently, the diagnosis is made during surgery. Both minimally invasive laparoscopic procedures and conventional open approaches can be used to undertake surgical treatments. Here, we report on an adult man’s successful laparoscopic repair of a left PDH, as well as the preoperative radiological diagnostic.

Massive hemoptysis in a patient with Eisenmenger syndrome, polysplenia and transverse liverMohsen Shafiepour M.D 1, Behnam Dalfardi M.D2, Ali Nemati M.D 3, Sina Bakhshaei M.D 4, Elahenaz Parsimood M.D 5Assistant Professor of Pulmonology; Afzalipour Hospital Research Center‚ Kerman University of Medical Sciences‚ Kerman‚ Iran.Email: m.shafiepour@kmu.ac.irAdvanced Thoracic Research Center, Tehran University of Medical Sciences, Tehran, IranEmail: B.dalfardi@kmu.ac.irAssistant Professor of Hematology and oncology, Afzalipour Hospital Research Center‚ Kerman University of Medical Sciences‚ Kerman‚ Iran.Email: ali_nemati802002@kmu.ac.irInternal medicine resident, UHS SoCal MEC, Temecula, California, USAEmail: sina.bakhshaei@uhsinc.comcardiovascular Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran (Corresponding author)Email: eliprs5@gmail.comAbstractIntroduction : Hemoptysis is defined as blood-streaked sputum from the lower parts of the respiratory tract. Hemoptysis, even in small amounts, is a frightening and an alarm sign for possible underlying conditions such as infections, pulmonary diseases, neoplastic conditions, cardiovascular alterations, vasculitis, traumatic events, hematological derangements, and iatrogenic or drug-induced events. The initial step in the evaluation of hemoptysis is to determine the source of bleeding.Case presentation : Herein, we report an unusual case of massive hemoptysis in a young patient with polysplenia and Pulmonary Artery Hypertension (PAH) in the setting of Eisenmenger syndrome. Chest radiography was suggestive of multiple lung opacities bilaterally. Chest Computed Tomography (CT) revealed a non-heterogeneous mass-like lesion measuring 4 × 5.2 × 5.6 cm in the superior segment of the inferior lobe of the left lung, concerning for accessory spleen. The patient underwent Video bronchoscopy, which showed tracheomalacia and active bleeding in the left main bronchus. The bleeding was controlled by Argon Plasma Coagulation (APC) technique. Broncho-alveolar lavage (BAL) was negative for acid-fast bacilli on staining and on culture. After stabilization, the patient was discharged home on medical management for PAH. On two-week follow-up, imaging revealed resolution of the pulmonary mass-like lesion.Conclusion : Our report highlights the importance of bronchoscopy in determining the bleeding source in patients with hemoptysis and managing it via the APC technique.Keywords: Hemoptysis; Pulmonary Hypertension; Eisenmenger syndrome; Polysplenia; Transverse liverINTRODUCTIONHemoptysis is defined as blood-streaked sputum from the lower parts of the respiratory tract. The initial step in the evaluation of hemoptysis is to determine the source of bleeding. Pseudo hemoptysis, which refers to blood expectoration via a source other than the bronchial or pulmonary system, should be ruled out by history and physical examination (1).Hemoptysis, even in small amounts, is a frightening and alarm sign. The clinical spectrum ranges from minor blood-stained sputum to major bleeding causing respiratory failure and hemodynamic instability. Underlying causes may vary from benign self-limiting conditions to severe and potentially life-threatening conditions. In terms of severity, hemoptysis is considered scant when presents with bleeding <5 mL, mild when <20 mL, and moderate when >20 ml, while massive hemoptysis is defined as bleeding amount of 100 mL/24 hours or more (2).Hemoptysis may derive from multiple underlying conditions, such as infections, pulmonary diseases, neoplastic conditions, cardiovascular alterations, vasculitis, traumatic events, hematological derangements, and iatrogenic or drug-induced events (Table 1) (3).In adults, acute respiratory tract infections (e.g., bronchitis, pneumonia), bronchiectasis, asthma, chronic obstructive pulmonary disease, and malignancy are the most common etiologies. Tuberculosis (TB) is a major cause of hemoptysis in endemic regions and in developing countries (4). However, in industrialized areas, bronchial carcinoma and bronchiectasis are more common culprits.Pulmonary artery hypertension (PAH) is a serious condition causing progressive obstruction and obliteration of the pulmonary vascular bed. PAH is a rare cause of hemoptysis, which is responsible for 0.2- 4% of the cases. Although, hemoptysis is a relatively more common finding in patients with Eisenmenger syndrome (1).In the past, depending on the severity and etiology of hemoptysis, several management strategies were recommended including supportive care, surgical resection, and lung transplant. Currently, the more commonly used strategy is bronchial artery embolization (BAE). In this technique, a particulate material is injected into angiographically identified abnormal bronchial arteries, helping in hemostasis. BAE is usually well tolerated; however recurrent bleeding is commonly associated with the procedure (6).Herein, we report a case of hemoptysis in a patient with Eisenmenger syndrome and polysplenia. We aim to portray the importance of bronchoscopy as both a diagnostic and therapeutic tool, which helped us to identify the source of bleeding and manage it via the BAE technique.CASE DESCRIPTIONHistoryA 34-year-old female with past medical history of Eisenmenger syndrome in the setting of Ventricular Septal Defect (VSD), who presented with 10 days’ history of cough, hemoptysis (about 300 ml/day), pleuritic chest pain, and exertional dyspnea. She did not report any fever, gum bleeding, or epistaxis.ExaminationOn physical examination the patient was tachypneic, tachycardic, and hypoxic with oxygen saturation of 85% in room air. Chest auscultation revealed left upper lobe crackles and holosystolic murmur in the lower sternal border. Also, she was found to have clubbing in her hands bilaterally.METHODS (DIFFERENTIAL DIAGNOSIS, INVESTIGATIONS, AND TREATMENT)Laboratory findings were significant for microcytic anemia (Hemoglobin 10.6 gm/dl), elevated erythrocyte sedimentation rate (ESR) at 23 mm/hr., and negative sputum for both Acid Fast Bacilli (AFB) stain and geneXpert. Chest radiograph revealed non-homogenous opacities in both lungs (figure 1). Computed tomography (CT) Chest showed a non-heterogeneous mass like lesion measuring 4 × 5.2 × 5.6 cm in superior segment of inferior lobe of the left lung (figure 2), in addition to a transversus liver and multiple spleens were noted (Figure 3). Echocardiography was remarkable for mild Pulmonary valve insufficiency, Pulmonary artery pressure (PAP) of 80 mmHg, abnormal septal motion, large membranous VSD, severe right ventricular (RV) enlargement, and left ventricular Ejection fraction (LVEF) of 55%.

DEFINING NORMAL REFERENCE RANGES OF LEFT VENTRICULAR GLOBAL LONGITUDINAL STRAIN AMONG DIFFERENT VENDORS: ARE WE THERE YET?Nanna Michele1 MD, Romero Acero Laura Marcela1 MD, Lee Pei-Lun 2 MDCardiac Care & Vascular Medicine / Albert Einstein College of MedicineJacobi Medical Center, Department of Medicine/Albert Einstein College of MedicineStrain and strain rate imaging have evolved significantly since their introduction two decades ago, providing an objective means to quantify both regional and global myocardial function [1]. Initially developed using tissue Doppler strain, strain imaging has largely transitioned to speckle-tracking echocardiography (STE), a technique that is angle-independent and offers improved feasibility and reproducibility. Left ventricular global longitudinal strain (LVGLS) has become an established measure of left ventricular (LV) systolic function with numerous clinical applications. However, despite its promise, LVGLS has not yet been widely adopted in real-world clinical practice. One major barrier is the variability across different echocardiographic vendors, which introduces inconsistency in measurements and complicates standardization efforts.Traditionally, left ventricular ejection fraction (LVEF) has been the most commonly used parameter for assessing LV systolic function and predicting outcomes. However, despite its widespread use, LVEF has notable limitations, including significant intra- and inter-observer variability, dependence on geometric assumptions, and susceptibility to technical artifacts such as endocardial dropout and foreshortening of the apex. Similar challenges exist for LVGLS, where accurate endocardial contour delineation and motion tracking are crucial for reliable assessment. Reproducibility of LVGLS using different vendors’ algorithm software remains controversial and has been described as acceptable by some [2] or shown to have significant discrepancies by others [3-5].Advancements in speckle-tracking echocardiography, including machine learning-driven algorithms, have improved strain analysis. However, a key limitation of strain imaging is that measurements remain dependent on proprietary software algorithms, leading to variability between vendors. Moreover, despite abundant literature, defining universal reference ranges remains a challenge, as different software platforms yield slightly different results. A proposed solution has been the use of intra-institutional vendor independent software capable of obtaining off line strain measurements. These vendor independent strain software packages have evolved but have not undergone rigorous external validation studies.The study by Arockiam et al. [6] addresses this gap by evaluating normal reference ranges for LVGLS using contemporary, vendor-neutral strain software in a cohort of healthy individuals. The authors examined 100 subjects across different age groups, using echocardiographic scans from General Electric (GE) and Philips systems. Four strain software packages—TomTec, EchoPAC, VVI, and Epsilon—were used to quantify LVGLS, enabling direct comparative and regression analyses. Their findings indicate that mean LVGLS values varied slightly across the four software packages, with EchoPAC producing the most negative strain values and VVI yielding the least negative values. Regression analyses identified sex, heart rate, LVEF, and the choice of strain software (particularly EchoPAC and VVI vs. TomTec) as significant contributors to LVGLS measurement variability. Despite differences across the four software platforms, the study provides reference ranges that may aid in defining normal, abnormal, and borderline LVGLS values for clinical application.Based on these results, the authors conclude that LVGLS measurements were feasible across all four strain software on both GE and Philips scans in this study. While acknowledging differences among the four strain software packages, by reporting LLNs and their 95%CI the authors provide helpful reference ranges to define normal, abnormal and borderline LVGLS values to enable clinical application. The results led the authors to cautiously recommend using the same strain software and their own respective reference ranges for interpreting and comparing LVGLS measurements.Importantly, the authors demonstrate that the inter-vendor variability of LVGLS is now comparable to, or even smaller than, the variability seen with LVEF. This marks a significant step toward the routine clinical application of LVGLS as an alternative or adjunct to LVEF. An increasing number of studies have suggested that GLS is superior to EF as a measure of LV function and as a predictor of mortality and cardiac events [7-10] . Previous reports have suggested that an absolute GLS of -12% represents severe systolic dysfunction and carries an adverse prognosis, and -15–16% identifies patients with relatively preserved EF at higher risk for future events. However, LVGLS reference range values associated with risk tiers have yet to be firmly established, in part due to lack of established lower limit of normal values.While the study represents a significant contribution to the field, some limitations should be acknowledged. The cohort predominantly comprised younger subjects, which may not reflect the typical age distribution seen in clinical practice. Since older patients often have more comorbidities affecting myocardial mechanics, the findings may not be fully generalizable. Most participants were white, limiting the applicability of the findings to ethnically diverse populations. A number of studies have provided reference ranges for specific ethnic groups. In the 2012 JUSTICE (Japanese Ultrasound Speckle Tracking of the Left Ventricle) study [5] of 817 healthy mostly male volunteers with average age 36 years, the overall mean full thickness, peak systolic GLS using GE equipment was reported as -21.3+ 2.1% . In a 2014 Italian study [11] of 260 Caucasian healthy mostly female volunteers with average age 44 years, the mean full-thickness, peak systolic GLS using GE equipment was reported as -21.5 +2.0% (lower limits of normal or average: 2 SD was 16.9% for men and 18.5% for women). Different values were obtained in a 2009 multicenter (Australian, European and American) study [12] of 242 healthy mostly female volunteers with average age 51 years in which mean full-thickness, peak systolic GLS using GE equipment was reported as -18.6+ 0.1%, with no significant differences among geographical regions. Given known ethnic differences in cardiac structure and function, further studies incorporating broader demographic diversity are needed.The study does not provide data on whether LVGLS measurements obtained from different ultrasound machines (GE vs. Philips) in the same patient yield consistent results across all vendor-neutral software platforms. This remains a crucial question for laboratories that use multiple echocardiographic systems. Additionally, the study focused solely on LVGLS and did not assess global circumferential strain, global radial strain, or strain rate measurements. These parameters are less commonly used in clinical practice due to their greater variability, but further investigations into their standardization remain necessary.Similarly, GLS is highest in the endocardium and lowest in the epicardium. To assess inter-vendor global strain differences the study results only apply to endocardial GLS, the only parameter that could be provided by all vendors. Results may not be valid if region of interest for GLS is set in the midwall, epicardial, or full thickness. Indeed, most companies now include software capable of mid/full wall tracking which preliminary data have shown to have similarly good inter-vendor bias and reproducibility as endocardial GLS [13].There is currently lack of reference values for segmental strain measurements in part due to suboptimal reproducibility and large inter-vendor measurement variability. The current study does not provide information regarding quantitative assessment of the magnitude of regional deformation. This leaves open the possibility that, inter-vendor differences for segmental strain values may be considerably higher than that reported for global values. The extent of spatial smoothing aimed at reducing noise in the regional tracking of speckles may vary in the different algorithms used by each vendor and may contribute to inter-vendor variability. This gap in knowledge relegates regional strain measurements to assessment of regional differences in polar strain maps rather than precise definition of numerical segment-specific strain values. While reductions in local strain may correctly identify areas of inflammation or fibrosis, the availability of reference values might enhance the ability to quantify regional abnormalities as compared to other imaging techniques.Thanks to continued collaboration between vendors and potential sharing of proprietary software has resulted in further reduction in inter-vendor variability. A recent report of the European Association of Cardiovascular Imaging (EACVI) Strain Standardization Task Force [13] aimed at comparing the current inter-vendor variability and reproducibility to the findings from their previous 2013 results evaluated 372 echocardiographic examinations performed in sixty-two subjects with a wide range of left ventricular (LV) function (ejection fraction from 30% to 64%) using ultrasound systems from six manufacturers.The results showed that both endocardial and mid/full-wall GLS measurements were comparable and within a very narrow range (maximum inter-vendor bias of 0.9% strain units) whereas in 2013, the maximum absolute difference was 3.7 % strain units, leading the authors to conclude that in contrast to the situation ten years earlier, a substantial improvement in inter-vendor bias has been accomplished. In addition, most companies now allow mid/full-wall tracking, which had similarly good inter-vendor bias and reproducibility as endocardial GLS.The study by Arockiam et al. [6] represents an important step toward the standardization of LVGLS measurements across different software platforms. By providing vendor-neutral reference ranges, the authors offer valuable insights that may facilitate the integration of strain imaging into routine clinical practice. However, persistent variability among independent vendors, albeit reduced, underscores the need for continued refinement in strain software and external validation in larger, more diverse populations. Moving forward, widespread adoption of vendor-neutral strain software, along with further multicenter studies, will be crucial for achieving true standardization. In the interim, clinicians should remain aware of the potential measurement discrepancies among software packages and ensure consistency by using the same strain analysis tool for serial patient evaluations.REFERENCES[1]. Sutherland GR, Di Salvo G, Claus P, et al. Strain and strain rate imaging: a new clinical approach to quantifying regional myocardial function. J Am Soc Echocardiogr. 2004;17(7):788-802.[2]. Manovel A, Dawson D, Smith B, et al. Assessment of left ventricular function by different speckle-tracking software. Eur J Echocardiogr. 2010;11(5):417-21.[3]. Biaggi P, Carasso S, Garceau P, et al. Comparison of two different speckle tracking software systems: does the method matter? Echocardiography. 2011;28(5):539-47.[4]. Nelson MR, Hurst RT, Raslan SF,et al. Echocardiographic measures of myocardial deformation by speckle-tracking technologies: the need for standardization? J Am Soc Echocardiogr. 2012;25(11):1189-94.[5]. Takigiku K, Takeuchi M, Izumi C, et al. Normal range of left ventricular 2-dimensional strain: Japanese Ultrasound Speckle Tracking of the Left Ventricle (JUSTICE) study. Circ J. 2012;76(11):2623-32.[6]. Arockiam A D, Dong T, Agrawal A, et al. Reference ranges of left ventricular global longitudinal strain by contemporary vendor-neutral echocardiography software in healthy subjects. Echocardiography (in press).[7]. Ersbøll M, Valeur N, Mogensen UM, et al. Prediction of all-cause mortality and heart failure admissions from global left ventricular longitudinal strain in patients with acute myocardial infarction and preserved left ventricular ejection fraction. J Am Coll Cardiol. 2013;61(23):2365-73.[8]. Mignot A, Donal E, Zaroui A , et al. Global longitudinal strain as a major predictor of cardiac events in patients with depressed left ventricular function: a multicenter study. J Am Soc Echocardiogr. 2010;23(10):1019-24.[9]. Stanton T, Leano R, Marwick TH. Prediction of all-cause mortality from global longitudinal speckle strain: comparison with ejection fraction and wall motion scoring. Circ Cardiovasc Imaging. 2009;2(5):356-64.[10]. Haugaa KH, Grenne BL, Eek CH, et al. Strain echocardiography improves risk prediction of ventricular arrhythmias after myocardial infarction. JACC Cardiovasc Imaging. 2013;6(8):841-50.[11]. Kocabay G, Muraru D, Peluso D, et al. Normal left ventricular mechanics by two-dimensional speckle-tracking echocardiography. Reference values in healthy adults. Rev Esp Cardiol (Engl Ed). 2014;67(8):651-8.[12]. Marwick TH, Leano RL, Brown J, et al. Myocardial strain measurement with 2-dimensional speckle-tracking echocardiography: definition of normal range. JACC Cardiovasc Imaging. 2009;2(1):80-4.[13]. Balinisteanu A E, Duchenne J, Puvrez A,et al. Inter-vendor variability in two-dimensional speckle tracking strain: a ten-year follow-up on the strain standardization task force inter-vendor comparison study. Eur. Heart J. Cardiovasc. Imaging. 2025; 26, Issue Supplement_1.

Models of infectious disease dynamics suggest that treatment, vaccination, and isolation are required for the control of infectious diseases. Considering that vaccination is one of the most effective methods to control infectious diseases, it is often not possible to rapidly vaccinate all susceptible populations in the early stages of the spread of infectious diseases due to the limitation of the number of vaccines, insufficient medical personnel, or the slow progress of vaccination efforts. Our simulation analysis by building an SVIWRD model found that the degree of negative impact of infectious diseases shown when young and old people were divided into two populations and vaccinated at different rates was different.Therefore, for the current problem of continued spread of COVID-19, we consider the infectious disease dynamics model to achieve the goal of making the risk of infection of COVID-19 lower by controlling the proportion of vaccination of elderly and young people. In this paper, we divided young and old people into two groups, established an SVIWRD model, performed single-objective optimization using Pontryagin's maximum principle, and used the Runge-Kutta method for numerical calculation and simulation, so as to arrive at a certain vaccination ratio that plays the effect of reduced negative impact of COVID-19.