Supplemental Digital Content is available in the text. Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.We recruited 30 154 randomly invited individuals age 50 to 64 years to SCAPIS (the Swedish Cardiopulmonary Bioimage Study). The study includes individuals without known coronary heart disease  and with high-quality results from CCTA and CAC imaging performed using dedicated dual-source CT scanners. Noncontrast images were scored for CAC. CCTA images were visually read and scored for coronary atherosclerosis per segment . External validity of prevalence estimates was evaluated using inverse probability for participation weighting and Swedish register data.In total, 25 182 individuals without known coronary heart disease were included (50.6% women). Any CCTA-detected atherosclerosis was found in 42.1%; any significant stenosis (≥50%) in 5.2%; left main, proximal left anterior descending artery, or 3-vessel disease in 1.9%; and any noncalcified plaques in 8.3% of this population. Onset of atherosclerosis was delayed on average by 10 years in women. Atherosclerosis was more prevalent in older individuals and predominantly found in the proximal left anterior descending artery. Prevalence of CCTA-detected atherosclerosis increased with increasing CAC scores. Among those with a CAC score >400, all had atherosclerosis and 45.7% had significant stenosis. In those with 0 CAC, 5.5% had atherosclerosis and 0.4% had significant stenosis. In participants with 0 CAC and intermediate 10-year risk of atherosclerotic cardiovascular disease according to the pooled cohort equation, 9.2% had CCTA-verified atherosclerosis. Prevalence estimates had excellent external validity and changed marginally when adjusted to the age-matched Swedish background population.Using CCTA in a large, random sample of the general population without established disease, we showed that silent coronary atherosclerosis is common in this population. High CAC scores convey a significant probability of substantial stenosis, and 0 CAC does not exclude atherosclerosis, particularly in those at higher baseline risk. Using coronary computed tomography angiography, we show that silent coronary atherosclerosis was common (42.1%), significant stenosis (≥50%) was less common (5.2%), and more severe forms were rarely found (1.9%) in a random sample of a middle-aged general population.Disease onset was delayed by 10 years in women. Higher prevalence of coronary atherosclerosis was observed with age and accumulation of risk factors.Coronary computed tomography angiography–detected atherosclerosis increased with increasing coronary artery calcification (CAC) score: All those with a high CAC score (>400) had atherosclerosis and 45.7% had significant stenosis, 5.5% of those with 0 CAC had atherosclerosis, and 0.4% had significant stenosis, with increasing prevalence at higher predicted risk.We describe the prevalence and characteristics of atherosclerosis in the general population without established disease, which lays the foundation for developing and designing successful high-risk screening strategies.Although there is a strong association between high CAC score and significant stenosis, atherosclerosis is not excluded in those with 0 CAC, especially in those at high baseline risk.930Editorial, see p 1 However, MI is still a common condition, with high morbidity and a 28-day mortality of 24% in Sweden.2 Improved strategies are needed to identify individuals at the highest risk of cardiovascular disease to complement population-based efforts.3Population strategies for prevention of cardiovascular disease have been successful and likely explain the reduction in the incidence of myocardial infarction (MI) in recent decades.5 With recent advances in imaging technology,6 it is now possible to noninvasively visualize atherosclerotic plaques using coronary computed tomography angiography (CCTA)7 to identify individuals with subclinical coronary heart disease and thus at risk of cardiac events.8 Previous reports using CCTA to assess coronary atherosclerosis have been performed in selected populations, either as health evaluations9 or clinical evaluation of patients with chest pain,11 but not in the general population. Knowledge of the true prevalence and characteristics of atherosclerosis in the general population without established disease is a prerequisite for developing and designing successful high-risk screening strategies.Postmortem and intravascular ultrasound studies have shown that most acute coronary events coincide with a large and often ruptured atherosclerotic plaque in the coronary arteries.13 Although CAC scoring improves prediction of cardiac events beyond traditional risk scores in population studies,15 the CAC score does not provide information on the exact localization of coronary atherosclerosis, degree of stenosis, and presence of noncalcified plaques. Data from symptomatic patients suggest that CCTA may add discriminatory capacity for future coronary events beyond that of CAC.16 However, this finding remains to be corroborated and there are no published studies comparing CCTA and CAC data in a population-based prevention study.Imaging of coronary artery calcifications (CAC) using noncontrast computed tomography (CT) has been widely used to identify individuals with calcified coronary atherosclerosis, and there is a positive relationship between CAC and degree of CCTA-detected atherosclerosis.17 SCAPIS involves both an extensive imaging protocol including CCTA and CAC scoring as well as a comprehensive examination protocol. The aim of the current study was to determine the prevalence and burden of CCTA-detected coronary artery atherosclerosis and its association with CAC scores in the general population without established coronary heart disease. This is the first report from SCAPIS based on all 30 154 recruited participants.SCAPIS (the Swedish Cardiopulmonary Bioimage Study), a general population-based prospective study, was designed to extensively characterize >30 000 men and women aged 50 to 64 years recruited at random from the population to obtain information that can be used to improve prevention strategies for cardiovascular disease.www.scapis.org). Between 2013 and 2018, men and women aged 50 to 64 years were randomly recruited from the census register at 6 sites in Sweden  and invited to a comprehensive examination as previously described.17 The multicenter study was approved by the ethical review board in Umeå (number 2010-228-31M). The participants gave written informed consent. Because of the sensitive nature of the personal data and study materials, they cannot be made freely available. However, by contacting the corresponding author or study organization (www.scapis.org), procedures for sharing data, analytic methods, and study materials for reproducing the results or replicating the procedure can be arranged following Swedish legislation.SCAPIS is a general population-based prospective study  on the CCTA images. Individuals were also excluded if they had previously had a MI, percutaneous coronary intervention, or coronary artery bypass grafting. Information on previous MIs and cardiac procedures was self-reported (in the study questionnaire) or provided by at least 1 previous diagnosis of MI or a cardiac procedure on the Swedish inpatient register . MI in registry data was defined as I21  or 410 (according to ICD-8 or ICD-9). Cardiac procedures were defined as either percutaneous coronary intervention or coronary artery bypass grafting using the codes FNA-FNG (according to ICD-10) or 3066, 3105, 3127, 3158, 3092, or 3080 (according to ICD-8 or ICD-9). Individuals were excluded from the CAC analyses if they did not have readable CAC images .Study inclusion is detailed in 17 In the present analyses, we used data from cardiac imaging, physical examinations, routine laboratory tests, accelerometry, a comprehensive questionnaire, and electronic health records reported to the Swedish inpatient register.The study procedures have been described in detail elsewhere.17 Briefly, CT was performed using a dedicated dual-source CT scanner equipped with a Stellar Detector . The CT scanners at each of the 6 sites were maintained using identical software and hardware throughout the study. CAC images were obtained using electrocardiogram-gated noncontrast CT imaging at 120 kV. In preparation for CCTA imaging, renal function was assessed and potential contraindications identified to exclude participants for whom administration of contrast media could pose a risk. A β-blocker (metoprolol) and sublingual glyceryl nitrate were given for control of heart rate and dilation of coronary arteries. The contrast medium iohexol  was administered at a dose of 325 mg I/kg body weight. CCTA was performed at 100 or 120 kV using 5 different protocols depending on heart rate, heart rate variability, presence of calcifications, and body weight.Cardiac imaging in SCAPIS has been described in detail previously.3 were identified with 3D-based picking and viewing tools. The area of calcification of each 3-mm slice was multiplied with an intensity factor and summed across slices for the whole coronary artery tree to a CAC score according to Agatston.18 CAC scores (in Agatston Units) were further categorized into 0, 1 to 10 , 11 to 100 (low), 101 to 400 (moderate), and >400 (high).All noncontrast image sets were reconstructed (B35f HeartView medium CaScore) and CAC were identified and scored using the syngo.via calcium scoring software . Lesions exceeding the calcium threshold of 130 Hounsfield units in at least 3 neighboring pixels in a volume of 1 mm19 Readers at the 6 sites visually read the CCTA image datasets and consecutively entered information into the SCAPIS electronic case report form. The readers attended yearly training and information sessions to assure consistency in reading and reporting.All contrast-enhanced CCTA image sets were reconstructed  and visually scored for atherosclerosis using syngo.via software. All readers (36 trained thoracic radiologists or cardiologists) had between 1 and >10 years of training in reading CCTA and a competence level 1 , level 2 , or level 3  in accordance with the American College of Cardiology Foundation/American Heart Association Clinical Competence Statement on cardiac CT.20 To streamline reading and increase quality of the most important findings, readers focused on the 11 clinically most relevant segments , which were compulsory to report; the remaining segments were only reported if they had atherosclerosis or calcium blooming. The coronary segments were visually examined for the presence of plaques and each plaque was visually characterized as calcified or noncalcified. We use the phrase “only noncalcified plaques” for participants who had exclusively noncalcified plaques in all affected segments and “any plaque noncalcified” for participants who had either only noncalcified plaques or a mix of noncalcified and calcified plaques. Per-segment status of the coronary vessel was defined as follows: no atherosclerosis, 1% to 49% stenosis; ≥50%  stenosis; not assessable because of calcium blooming (see following); or not assessable because of technical failure (see following) or segment missing. Luminal obstruction was defined by visually estimating diameter stenosis (using the average of the longest and shortest diameter at the site of stenosis).For reporting coronary atherosclerosis from CCTA, we used the 18 coronary segment model defined by the Society of Cardiovascular Computed Tomography.22 If calcium content of the segment was severe and precluded judgment of level of stenosis, the segment was classified as having a calcium blooming artifact and, in the main analyses, the level of stenosis was set to 1% to 49%. In a sensitivity analysis presented in the Data Supplement, the level of stenosis for a calcium blooming artifact was set to ≥50%.Defining the level of stenosis from calcified plaques is a challenge for CCTA and calcifications are known to overestimate the level of stenosis.in the Data Supplement.Technical artefacts  of a magnitude that made judgment of segment status invalid were reported as technical failures when reading the segment and coded as missing data in analyses of coronary atherosclerosis prevalence. Details on calcium blooming, technical failures, reproducibility, and consistency across sites are presented Participants with ≥50% stenosis were classified as having 1-, 2-, or 3-vessel disease and whether they had left main or proximal LAD disease. Segments with noncalcified plaques were also identified.23 and the pooled cohort equation (PCE).24 The following risk categories were used: for SCORE, low (<2%), moderate (2% to 5%), and high (>5%) 10-year risk of atherosclerotic cardiovascular disease ; and for PCE, low (<5%), borderline (≥5 to <7.5%), intermediate (≥7.5 to <20%), and high (≥20%) 10-year risk of atherosclerotic cardiovascular disease . The extent of CCTA-detected atherosclerosis in relation to risk factor burden assessed by PCE was also determined in those with a CAC score of 0.The extent of CCTA-detected atherosclerosis was compared with risk factor burden using both the Systematic Coronary Risk Evaluation (SCORE)25: the age-matched population in the SCAPIS catchment areas, which reflects the population that was invited to participate in SCAPIS; and the age-matched population of Sweden as a whole using inverse probability for participation weighting (see the Data Supplement).Data were analyzed without imputations and we estimated the prevalence of coronary atherosclerosis in the general population based on individuals who agreed to participate in SCAPIS. As a sensitivity analysis to test the external validity of this estimate, we standardized the SCAPIS sample to 2 target populations of interest using sociodemographic register datathe Data Supplement).The delayed onset of CCTA-detected atherosclerosis (1% to 49% stenosis and ≥50% stenosis) in women versus men was modeled to identify the minimal value of the sum of the squared differences between the annualized prevalence in women and men , current smoker, cholesterol-lowering medication, antihypertensive medication, diabetes (self-reported), systolic blood pressure, total cholesterol, and high-density lipoprotein cholesterol.26 Data were analyzed by authors M.A., C.B., and E.B.Reporting of this study follows the recommendations of the STROBE statement .Table I in the Data Supplement). The overall participation rate of those invited was 50.3% and was similar between ages and sexes (Table II in the Data Supplement). Of the total number recruited, 29 613 underwent CT and 27 385 underwent CCTA. Characteristics of participants who underwent CT but not CCTA (n=2228) are described in Table III in the Data Supplement. The main reasons for not undergoing CCTA were issues with the safety of the participant (44%), unwillingness to be exposed to the examination (24%), or issues with venous access . The median effective radiation dose from CAC imaging and CCTA imaging was 0.34 mSv  and 1.33 mSv , respectively.In total, 30 154 individuals were recruited to SCAPIS (characteristics presented in Table V in the Data Supplement). Results on reading consistency of CCTA images are presented in Table VI in the Data Supplement, and Figures II and III in the Data Supplement. Technical artefacts making judgment of segment status invalid are reported in Table VII in the Data Supplement. Characteristics of individuals with technical failures in any of the 4 most proximal segments are described in Table VIII in the Data Supplement.After excluding 1805 individuals because image quality of their proximal segments was poor and a further 398 individuals because they had previous MI or coronary intervention, 25 182 participants remained for the analysis of CCTA-detected atherosclerosis .After excluding a further 168 individuals who did not have readable CAC images, 25 014 participants were included in the combined analyses of CCTA and CAC . Modeling showed that the delay in disease onset in women compared with men was ≈10 years for both 1% to 49% stenosis and ≥50% stenosis . Prevalence of atherosclerosis increased with risk factor burden, being 2.1and 2.9 times more common in participants at high versus low risk according to SCORE and PCE, respectively .Of the 25 182 participants in SCAPIS who underwent a technically successful CCTA and had not previously experienced a MI or coronary intervention, any CCTA-detected atherosclerosis was found in 42.1%  and any significant stenosis (≥50%) in 5.2%  and severe forms of coronary atherosclerosis with significant stenosis in left main, proximal LAD, or 3-vessel disease increased from 1.9% to 3.7% of the population.In the analyses presented in the main text, calcium blooming was set to 1% to 49% stenosis. When calcium blooming was set to ≥50% stenosis, the prevalence of any significant stenosis increased from 5.2% to 9.3% (Table XI in the Data Supplement). The same distribution was found in participants in the early developmental phase of atherosclerosis , with proximal LAD most often involved , with no apparent differences in the distribution between sexes or age groups  whereas a mix of 1 or more noncalcified plaques together with calcified plaques was observed in 8.3% of the population  followed the same pattern as seen for CCTA-detected atherosclerosis, with 40.2% of the population being CAC-positive and a higher prevalence with age and in men . A few participants had only noncalcified plaques on CCTA but had CAC scores 1 to 10 (n=32), 11 to 100 (n=10), and even 101 to 400 (n=3). In the cohort with both valid CCTA and CAC images, the number of participants with 0 CAC but CCTA-detected plaques was 818 (3.3%), slightly higher than the number with only noncalcified plaques on CCTA  did not have CCTA-detected atherosclerosis despite having CAC scores >0. The majority of these (n=312) had ultralow CAC scores (1 to 10) and the scores were mainly in the lower range of this category . In participants with ultralow CAC scores, body mass index was slightly higher in those without CCTA-detected atherosclerosis than in those with CCTA-detected atherosclerosis . In the population with 0 CAC, the participants with CCTA-detected atherosclerosis (n=818) were more often male, had a higher age, were more likely to be smokers, had higher cholesterol and lower high-density lipoprotein, and higher blood pressure, and were more often obese compared with participants without CCTA-detected atherosclerosis (Tables XII and XIII in the Data Supplement). These risk factors (with the exception of current smokers) were also more common in participants with a CAC score >0 (n=367) versus those with 0 CAC in the population without CCTA-detected atherosclerosis (Tables XII and XIII in the Data Supplement).The risk profile of participants with 0 CAC but CCTA-detected atherosclerosis (n=818) was between that of participants with 0 CAC and no CCTA-detected atherosclerosis and that of participants with CAC scores >0 and CCTA-detected atherosclerosis  was less common (in 5.2% of the population) and more severe forms of coronary atherosclerosis such as left main, proximal LAD, or 3-vessel disease were rarely found (in only 1.9% of the population). A higher prevalence of coronary atherosclerosis was observed in men and with higher age and accumulation of risk factors. CCTA-detected atherosclerosis increased with increasing CAC score category but subgroups of participants could be identified whose coronary atherosclerosis was not accurately represented by their CAC score.27 making comparisons with the general population difficult. Several population-based imaging studies have used CT to quantify CAC as a surrogate marker of atherosclerosis and showed a prevalence of a positive CAC between 50% and 89% dependent on age.30 However, no estimates of coronary artery stenosis can be derived from these studies.31 Earlier reports using CCTA, which have shown prevalence of atherosclerosis ranging between 22% and 43% and significant stenosis at 5% to 8%,32 are from selected populations only. True population estimates of prevalence are of importance if we are to design and apply successful screening strategies.33 Using inverse probability for participation weighting, we showed that our population was representative of the age-matched background population with only minimal selection bias. Thus, the prevalence of CCTA-detected coronary atherosclerosis in the general population reported in our study closely reflects the situation in Sweden. According to disease statistics from Europe and the United States,35 Sweden has an incidence of cardiovascular disease similar to that of many other western countries. In addition, we confirmed a 10-year delay in the development of both nonobstructive (1% to 49% stenosis) and obstructive (≥50% stenosis) silent coronary atherosclerosis in women, in agreement with earlier estimates of a 10-year difference between men and women in the onset of atherosclerosis-related clinical cardiovascular disease.24Previous data on the prevalence of coronary atherosclerosis in the general population are rare. A number of autopsy studies have reported the prevalence of coronary atherosclerosis, but these studies are often in small and highly selected populations and use a variety of reporting systems, 37 and suggesting that atherosclerosis has a predilection for proximal branching sites perhaps with turbulent flow patterns.39 Proximal LAD was also the most common location of significant stenosis. Although the cross-sectional design of our study prevents us from showing how atherosclerosis develops over time, we identified individuals with only 1 affected coronary segment who are likely in the early developmental phase of coronary atherosclerosis. We observed that proximal LAD was also the most common location of atherosclerosis in these individuals.Our results show that proximal LAD was the most common location for plaques, corroborating early autopsy studies7 Whereas the prevalence of participants with only noncalcified plaques on CCTA was low (2.4%), the percentage of participants with noncalcified plaques mixed among plaques with calcifications was higher and 14.2% of men aged 60 to 64 years had noncalcified plaques. However, it is well-known that not all plaques will lead to clinical events, and future longitudinal studies are required to determine whether the presence of noncalcified plaques confers an increased risk of future events.Noncalcified plaques have been suggested as a sign of a more vulnerable form of coronary atherosclerosis prone to cause events, although their role in causing cardiovascular events needs to be established.41 In participants with a high CAC score (>400), the frequencies of coronary stenosis ≥50% and very severe forms of coronary atherosclerosis were 45.7% and 20.3%, respectively. However, there were discrepancies between CCTA and CAC data. In participants with an ultralow CAC score (1 to 10), 22.0% of women and 29.7% of men had 2 or more coronary segments with CCTA-detected atherosclerosis, and 7.0% of participants with a low CAC score (11 to 100) had coronary stenosis ≥50%. It was also evident that CCTA and CAC imaging provided complementary data on coronary atherosclerosis because not all calcifications detected using CAC scoring were verified as CCTA-detected atherosclerosis by the readers. This was mainly seen in participants with ultralow CAC score (1 to 10) and could be explained by difficulties in assessing such low CAC scores with high reproducibility42 and the well-known difficulties in identifying small calcifications in the presence of iodinated contrast media.43 Furthermore, CCTA-detected atherosclerosis in participants with 0 CAC was sometimes reported as calcified from CCTA images. These differences could in some cases be attributable to miscoding but most likely result from differences in the methodology to detect calcification.44 If we define noncalcified plaques as atherosclerosis in participants with 0 CAC, as would be the situation in a CAC screening program, the prevalence of participants with only noncalcified plaques would be 3.3%, higher than the prevalence of all noncalcified plaques detected using CCTA (2.4%).In this large population study comparing CCTA and CAC data, we observed a positive association between CCTA-detected atherosclerosis and CAC scores, consistent with previous observations.40 Recent US guidelines state that the CAC score could be used in primary prevention to improve classification of individuals identified by PCE to be at intermediate 10-year risk of atherosclerotic cardiovascular disease; a CAC score of 0 would indicate a lowered risk and therefore not favor treatment with statins, which would otherwise be recommended in this group.45 However, studies and guidelines have questioned the negative predictive value of 0 CAC because significant atherosclerosis in the absence of CAC is possible.46 In the age group recruited to the current study (50 to 64 years), a large proportion would be expected to have 0 CAC (and here we report 60%). Of the group with 0 CAC in our study, 5.5% (4.3% of women and 7.3% of men) had CCTA-detected atherosclerosis in their coronary arteries. The risk factor burden in the group with 0 CAC but CCTA-detected atherosclerosis was generally higher than in the group with 0 CAC and no CCTA-detected atherosclerosis. In our population with 0 CAC and at intermediate risk as defined by PCE, 9.2% had CCTA-detected atherosclerosis, and would thus have been misclassified (according to US guidelines45) as having a lower than intermediate risk. The US guidelines do not recommend using 0 CAC to indicate a lower risk when the risk factor burden is large and the likelihood of noncalcified plaques could be high.45 Indeed, we showed that CCTA-detected atherosclerosis was present in a subset of our population with a CAC score of 0 who were currently smokers (6.8%), had a strong family history of MI (6.0%), or had diabetes (8.1%). Data from SCOT-HEART 47 and PROMISE 48 suggest that CCTA-detected coronary atherosclerosis, irrespective of degree of stenosis, is an important driver of clinical events in symptomatic populations. Follow-up studies are required to determine whether CCTA-detected coronary atherosclerosis is associated with similar risk in an asymptomatic population.A CAC score of 0 is generally considered a very good prognosis.This study has limitations. Because this is a large-scale study in the general population, we used stringent safety criteria, including use of low-dose radiation, avoiding repetition of nondiagnostic scans, and strict risk management for contrast injections, which resulted in a relatively high exclusion rate. Although we successfully scanned and obtained high-quality CCTA images from 86% of the SCAPIS population, a more aggressive imaging strategy could be applied in a real-world screening situation. The readers had access to both contrast and noncontrast image sets and the readings of CCTA and CAC data are therefore not independent.In conclusion, our study showed that (1) silent coronary atherosclerosis is common in the general population without established disease, (2) coronary atherosclerosis detected using CCTA is associated with CAC scores, and (3) subgroups of participants could be identified whose coronary atherosclerosis was not accurately represented by their CAC score, showing a potential additive value of CCTA imaging.Data Supplement.The authors thank Dr Rosie Perkins  for editing the manuscript. The study organization is acknowledged in the This study received funding from the Swedish Heart-Lung Foundation, Knut and Alice Wallenberg Foundation, Swedish Research Council and Vinnova (Sweden’s Innovation agency), University of Gothenburg and Sahlgrenska University Hospital, Karolinska Institutet and Stockholm county council, Linköping University and University Hospital, Lund University and Skåne University Hospital, Umeå University and University Hospital, and Uppsala University and University Hospital.Dr Ahlström is a founder and employee of Antaros Medical AB. Dr Hagström received research grant funding from Pfizer (significant), Amgen (significant), and DalCor National coordinator (modest), and consulting or honoraria from AstraZeneca, Amgen, Sanofi-Aventis, Novartis, and NovoNordisk (modest). Dr Sundström reports stock ownership in companies providing services to Itrim, Amgen, Janssen, Novo Nordisk, Eli Lilly, Boehringer, Bayer, Pfizer, and AstraZeneca. Dr Söderberg reports speakers honoraria and advisory board participation for Actelion Ltd. The other authors report no conflicts.MethodsData Supplement Figures I–VData Supplement Tables I–XIII


A new method of non-invasive approach, termed as AccuFFRct, for calculating FFR based on coronary computed tomography angiography (CCTA) and computational fluid dynamics (CFD) has been proposed. However, its diagnostic accuracy has not been validated.Fractional flow reserve This study sought to present a novel approach for non-invasive computation of FFR and evaluate its diagnostic performance in patients with coronary stenosis.A total of 54 consecutive patients with 78 vessels from a single center who underwent CCTA and invasive FFR measurement were retrospectively analyzed. The CT-derived FFR values were computed using a novel CFD-based model . Diagnostic performance of AccuFFRct and CCTA in detecting hemodynamically significant coronary artery disease (CAD) was evaluated using the invasive FFR as a reference standard.r = 0.76 and r = 0.65 on per-patient and per-vessel basis, respectively, both p < 0.0001). Area under the curve (AUC) values of AccuFFRct for identifying ischemia per-patient and per-vessel basis were 0.945 and 0.925, respectively. There was much higher accuracy, specificity and AUC for AccuFFRct compared with CCTA.Diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for AccuFFRct in detecting FFR ≤ 0.8 on per-patient basis were 90.7, 89.5, 91.4, 85.0 and 94.1%, respectively, while those of CCTA were 38.9, 100.0, 5.71, 36.5 and 100.0%, respectively. The correlation between AccuFFRct and FFR was good (AccuFFRct computed from CCTA images alone demonstrated high diagnostic performance for detecting lesion-specific ischemia, it showed superior diagnostic power than CCTA and eliminated the risk of invasive tests, which could be an accurate and time-efficient computational tool for diagnosing ischemia and assisting clinical decision-making. Accurate diagnosis of stenosis severity is essential for doctors in therapeutic decision-making regarding the need for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Coronary computed tomography angiography (CCTA) has emerged as a useful tool for evaluating coronary artery disease (CAD) severity . HoweverCT computation process, parallel supercomputers are needed [Computational fluid dynamics (CFD), as applied to CCTA images, represents a novel technique for assessing the physiological significance of CAD . CT-derie needed . Thus, aIn this study, a novel CT-derived FFR method, AccuFFRct, which efficiently computes lesion-specific non-invasive FFR based on anatomic and functional information, was used to assess its feasibility and diagnostic accuracy with wire-based FFR as a reference standard.The study population consisted of 54 patients with 78 vessels, including 34 males and 21 females. 45 (58%) lesions were located in left main or left anterior descending arteries, 10 (13%) were in left circumflex arteries and 14 (18%) were in right coronary arteries, there were 9 multi-vessel lesions. Detailed patient baseline characteristics are summarized in Table r = 0.76 and 0.65, p < 0.0001) and agreement (mean difference 0.06 ± 0.07) were observed. Representative patient case from the study is shown in Fig. The correlation and agreement between AccuFFRct and FFR on a per-patient and per-vessel basis are shown in Figs. The average AccuFFRct was 0.83 ± 0.10. Among all 78 vessels, there were 20 true positives (TP), 50 true negatives (TN), 6 false positives (FP), and 2 false negatives (FN) using FFR as the reference standard. With AccuFFRct ≤ 0.8 taken as the cut-off value of ischemia-causing stenoses (FFR ≤ 0.8), the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of AccuFFRct for diagnosis of ischemia-causing stenoses on the per-patient basis were 89.5, 91.4, 85.0, and 94.1%, respectively. The diagnostic accuracy was 90.7%. For the per-vessel assessment, the diagnostic accuracy, sensitivity, specificity, PPV, and NPV for AccuFFRct were 89.7, 90.5, 89.5, 76.0 and 96.2%, respectively. Detailed information of diagnostic performance of AccuFFRct is summarized in Table The ROC curves of AccuFFRct and CCTA on a per-patient and per-vessel basis are shown in Fig. r = 0.76 (p < 0.001) and agreement with invasive FFR. The overall diagnostic accuracy of AccuFFRct in predicting hemodynamically significant CAD (defined by FFR ≤ 0.80) was 90.7 and 89.7% on a per-patient and per-vessel basis, respectively. In this population, the accuracy of CCTA was only 61.8 and 58.1% for per-patient and per-vessel, respectively. The diagnostic accuracy of AccuFFRct is much higher than CCTA in the functional evaluation of lesion-specific ischemia. The cause is that CCTA often overestimates stenosis severity, and existing studies showed that less than 50% of CCTA-defined severe stenoses caused ischemia [We have developed a novel method that allows fast computation of FFR from CCTA images alone. In the study on a population of 54 patients with stenoses in 78 coronary vessels, AccuFFRct showed a good correlation with Pearson’s correlation coefficient ischemia , 13. ConCT, Heartflow) exhibited good correlations with invasive FFR, with diagnostic accuracy ranging from 73 to 86% and AUCs of FFRCT in detecting lesion-specific ischemia ranging from 0.81 to 0.90 [CT showed excellent diagnostic performance compared with CCTA, SPECT and PET and reduced more than one-half ICA in clinical practice [CT to guide ICA planning and revascularization could reduce costs and improve clinical outcomes. Furthermore, a recent trial including 5083 patients represented that FFRCT could provide much more useful information for clinical decision-making and FFRCT-guided patient management enhanced one-year survival free of major adverse cardiac events [CT-derived FFR methods can estimate FFR from typically acquired CCTA images without additional image acquisition, CCTA protocols, and medication administration modification. The diagnostic performance of such approaches has been validated and verified , 14, 15. to 0.90 . FFRCT spractice , 17. Hlapractice  demonstrc events , 20. Besc events , 22. Thec events . This alc events , 24 showc events . Besidesc events . In addic events , 28. On c events , 30, andc events , howeverCT and cFFR. The sensitivity, specificity, PPV, and NPV were 90.5, 89.5, 76.0 and 96.2%, respectively, while those for FFRCT were 84%, 86%, 61%, and 95%, respectively. μCT-FFR showed good diagnostic performance with 1% higher accuracy, While AccuFFRct resulted in slightly better sensitivity. It should be noted that higher sensitivity means less false negatives, which were critical in clinical application because false-negative results might put patients in danger for wasting the best treatment time. AccuFFRct showed an AUC of 0.945 for a per-patient basis and 0.925 per-vessel basis for categorizing functionally significant stenoses. The AUCs for FFRCT, cFFR, ML-based cFFR, μCT-FFR and TreeVes-Net-based FFR were 0.9, 0.92, 0.84, 0.92, 0.92, respectively. One cannot say AccuFFRct was superior in defining ischemia, but AccuFFRct did show very competitive results among similar works, and the diagnostic performance could be further optimized with future studies focusing on computational condition settings and algorithms, etc.Our study demonstrated credible results using AccuFFRct for exploring ischemia-causing stenosis comparing with above-mentioned works. The overall diagnostic accuracy of AccuFFRct was 89.7% on the per-vessel basis, which is higher than that of FFRCT requires significant computational time (1–4 h) due to the need of data transfer to off-site supercomputers [Except for the good diagnostic performance of AccuFFRct, the advantage of AccuFFRct lies in its time-efficient and convenient workflow. The application of FFRomputers . Workstaomputers , 32, 33.Though invasive FFR measurement is relatively safe in clinical use, risks and other limitations are still inevitable. Kumsars et al.  reportedThe main limitation of this study is its relatively small sample size with all CCTA data from a single center. A multi-centered study with large sample size is necessary to validate AccuFFRct further. In this study, the workflow and analysis were all performed by professionals. Thus training of normal medical staff is essential to ensure reliable execution of AccuFFRct analysis.The novel CFD-based CT-FFR method, AccuFFRct, is influential in determining significant functional CAD in a time-efficient manner with good diagnostic performance. It may emerge as a safe, efficient, and credible tool for evaluating coronary stenosis severity during diagnostic CCTA. In the future, algorithms would be continuously updated, some computational conditions or assumptions could also be optimized to assure clinically reliable results and to help more patients. A multicenter prospective clinical trial would be conducted to study the accuracy and clinical suitability of the algorithm for different types of stenosis, such as left main lesion, tandem lesion and bifurcation lesion.This was a retrospective, observational, analytical study conducted at The Second Affiliated Hospital of Zhejiang University School of Medicine. Patients who had undergone coronary computed tomography angiography (CCTA) and invasive FFR measurements within 2 months were included. This study was approved by the Institutional Review Board of the hospital and informed consent of the patients was waived.The study population comprised 54 stable patients with suspected or known CAD who underwent CCTA and FFR measurements between January 2016 and September 2017. Exclusion criteria included individuals with prior myocardial infarction, prior coronary artery bypass surgery (CABG), prior stenting at the lesion of interest, significant motion or blurring artifact in CCTA, occlusion in any major coronary artery.CCTA was performed using a dual-source 128-slice CT scanner . Medications were administered individually and different CCTA scan modes were chosen according to patients’ heart rate conditions. The tube voltage and tube current were set based on the body mass index of the patients. All CT images were reconstructed with a slice thickness of 0.5 mm. The CCTA image data was assessed in the central AccuFFRct core laboratory  and selected for subsequent AccuFFRct calculation and analysis. The flowchart of this study is displayed in Fig. Invasive coronary angiography (ICA) was performed within 30 days after the CCTA acquisition according to standard practice. FFR measurements were conducted after inducing the maximum hyperemia by intravenous injection of adenosine at 180 μg/kg/min. FFR was defined by dividing the mean pressure distal to the lesion by the mean aortic pressure under hyperemic condition, and an FFR value of ≤ 0.80 was considered hemodynamically significant. FFR data were transferred to the central AccuFFRct core laboratory for the following analysis by independent, blinded readers.Using the most recent AccuFFRct analysis software , analysis was performed in a blinded fashion in the central AccuFFRct core laboratory.Anatomical model reconstruction and segmentationIn this step, the anatomical geometry model of coronary arteries and ventricles can be obtained accurately from CCTA image data. First of all, the fast marching algorithm and colliding fronts algorithm were applied to segment aorta and coronary tree, differentiating them from other anatomic parts which were also include in CCTA image data. Subsequently, the optimal vessel borders were identified using the level-set method base on segmented CCTA images to ensure the real vessel shape. Then with an automatic geometry cleaning algorithm, the anatomical model of the coronary tree was obtained by marching cubes method  and the In addition, though the CT images included in this study were relatively good, general CT data that meet the standard of Digital Imaging and Communications in Medicine (DICOM) with a slice thickness < 1 mm is compatible with AccuFFRct, which means our technique can be used in numerous hospitals.Mesh generation and boundary conditionsQ ∝ Mk) and the flow rate was 2–4 times of resting condition at hyperemia. The blood flow rate at the outlet of each branch was calculated using Murray’s law (Qi ∝ d3), and the rigid wall with no-slip boundary condition was applied to the vessel wall.The anatomical model of coronary arteries should be pre-processed, including hole checking, smoothing, boundary face editing of the 3D model, and then it would be transformed into a mesh model for later numerical CFD simulation to obtain the flow field of blood. In general, millions of mesh elements with different sizes were generated based on the structure of an anatomical model. In general, the maximum mesh size was limited as 0.3 mm for the best balance of computational precision and time based on previous mesh sensitivity tests, coarser mesh may lead to bigger error. Boundary conditions were the physical and physiological conditions applied to the mesh model to simulate the interaction between coronary arteries and related body parts. In this study, the patient-specific blood flow and aortic pressure were set as the inlet boundary condition. The resting blood flow was estimated by myocardium mass  and incompressible [The flow field information, including pressure and velocity at each mesh element, could be calculated by solving the fluid governing Navier–Stokes equations using the finite volume method. In this study, blood was modeled as Newtonian fluid  was evaluated by calculating sensitivity, specificity, PPV, NPV and overall accuracy. Using FFR as a reference standard, sensitivity was defined by true positives divided by the sum of all true-positive and false-negative cases, specificity was defined as true negatives divided the sum of all true-negative and false-positive cases, PPV = TP/(TP + FP), NPV = TN/(TN + FN) and accuracy = (TP + TN)/(TP + FP + TN + FN). Pearson correlation was used to quantify the degree of correlation between invasive FFR and AccuFFRct in detecting ischemia-causing stenoses. The area under the curve (AUC) derived from receiver-operating characteristic (ROC) curve analysis were computed using invasive FFR as the reference standard for checking classification performance (positive or negative for ischemia-causing) of AccuFFRct. The Bland–Altman statistics were also performed to assess the agreement of FFR and AccuFFRct. A two-sided P value of less than 0.05 was considered statistically significant. All statistical analyses were performed using MedCalc .


Glycyrrhiza and Sargassum are one pair of the “18 incompatible medicaments,” which in theory cannot be used together. However, since ancient times, many reports have described using compounds containing both Glycyrrhiza and Sargassum to treat diseases. Haizao Yuhu Decoction (HYD), which contains both ingredients, is mainly used to treat goiter. Chinese Pharmacopoeia officially recorded three varieties of Glycyrrhiza: Glycyrrhiza uralensis, Glycyrrhiza inflata, and Glycyrrhiza glabra. These three varieties have certain differences in chemical composition and pharmacological effects. The purpose of the present study was to investigate whether the HYD containing different varieties of Glycyrrhiza and Sargassum had different therapeutic effects in rats with goiter and to elucidate the underlying mechanism of any difference. In this study, propylthiouracil (PTU) was used to replicate the goiter model, then HYDs containing different varieties of Glycyrrhiza were used for treatment for four weeks, and then the relevant indicators were tested. The results demonstrated that HYD had antigoiter effects, alleviated the pathological changes in the thyroid tissue, and restored the abnormal serum levels of hormones related to thyroid function induced by PTU. HYD containing Glycyrrhiza uralensis had the best therapeutic effect in rats with PTU-induced goiter. The antigoiter effect of HYD may function through the hypothalamic-pituitary-thyroid (HPT) axis, inhibit the expression of the Tg and NIS genes, and regulate the synthesis of thyroid hormones, thereby reducing the excessive stimulation of TSH in thyroid cells. In addition, HYD also prevented goiter by promoting thyroid cell apoptosis and inhibiting the ERK/RSK1 pathway of cell proliferation. In conclusion, three types of HYD had different therapeutic effects in rats with goiter, which might be caused by the compatibility of different varieties of Glycyrrhiza and Sargassum.In traditional Chinese medicine,  Glycyrrhiza and Sargassum are one pair of these eighteen antagonistic medicaments and should therefore not be used together, at least in theory. However, so far, these herbs have been used in concert for at least a thousand years. For example, one study found 17 ancient prescriptions containing this pair of herbs [Haizao Yuhu Decoction (HYD), which contains Glycyrrhiza and Sargassum, was first recorded in the Ming Dynasty, approximately 400 years ago. It has been commonly used to treat goiter [Sargassum had distinct effects on rats with goiter. Specifically, serum thyroid function-related hormone levels and related mRNA expression varied among the experimental groups [Glycyrrhiza uralensis (Wu La Er Gan Cao), Glycyrrhiza inflata (Zhang Guo Gan Cao), and Glycyrrhiza glabra (Guang Guo Gan Cao) are the three different species of Glycyrrhiza that are officially recorded in the Chinese Pharmacopoeia. These varieties have different pharmacological effects, chemical compositions, and contents [Sargassum. In the present study, we investigated whether the therapeutic effects of three HYDs differed among the Glycyrrhiza varieties in rats with PTU-induced goiter. We also assessed related indices of the hypothalamic-pituitary-thyroid (HPT) axis, as well as thyroid cell apoptosis and proliferation, to explore the mechanism of goiter inhibition by HYD.The “18 incompatible medicaments” is an important aspect of clinical monographs in traditional Chinese medicine (TCM). The herbs t goiter , vocal pt goiter , benign t goiter . In a prl groups . Glycyrrcontents , but no Glycyrrhiza have been described in Chinese Pharmacopoeia, three types of HYD were included in this study. Three types of HYD were HYD-uralensis (HYD-U), HYD-glabra (HYD-G), and HYD-inflata (HYD-I). In addition, Chinese Pharmacopoeia stipulates that Hai Dai and Kun Bu are the same herbs, so a double dose of Kun Bu was used instead. The names of herbs and daily adult doses are listed in Glycyrrhiza was identified as different varieties according to deoxyribonucleic acid (DNA) extraction and polymerase chain reaction (PCR) amplification by Professor Liu . We converted the adult dose into the rat dose based on the equivalent body surface area of humans and rats. The herbal drugs were decocted twice in water and concentrated to a density of 1.602 g/ml using heating evaporation. Propylthiouracil (PTU) and euthyrox were both obtained from Beijing Changdian Yingsongtang Pharmaceutical Co., Ltd . The tablets were dissolved in water to a density of 1 mg/ml and 2 ug/ml.HYD is a traditional Chinese classic formulation, which is composed of 12 kinds of Chinese herbs. Since three different species of μm). The detection conditions were referred to the Chinese Pharmacopoeia and the previous experiments of the research group [The contents of glycyrrhizic acid, liquiritin, forsythin, hesperidin, ferulic acid, and osthole in three HYDs were analyzed by high-performance liquid chromatography (HPLC). The HPLC machine model was Agilent1100, and the column model was ZORBAX SB-Aq  2011-0024). All experimental procedures were approved by the Animal Ethics Committee of the Beijing University of Chinese Medicine on October 9, 2019 (No. BUCM-4-2019100903-4011). Rats were maintained in a SPF laboratory animal room fed with sufficient food and water.th day, 15 rats in the control group and 25 rats in the other groups were selected. The blood was taken from the inner canthus with ether anesthesia, and the serum levels of triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were detected to prove the success of the model establishment. Meanwhile, drug treatment was started on the 15th day and continued to be administered for 4 weeks, and the doses were as follows: euthyrox , HYD-U , HYD-I , and HYD-G . However, rats in the control and model groups received deionized water . According to the previous report of our research group [The 90 male Wistar rats were randomly divided into six groups with 15 rats in each group. They were named as follows: control, model, euthyrox, HYD-U, HYD-I, and HYD-G. The model of goiter was replicated by intragastric gavage of propylthiouracil (PTU). Euthyrox was the positive control drug. Except for the control group rats, all the other rats were given PTU for 14 consecutive days in the morning at a dose of 0.01 g/kg/d to establish the goiter model. On the 15ch group , except During the entire experiment, the behavior, defecation, and fur status of each group were observed. The body weight and rectal temperature of each rat were measured at the beginning of the study and then once a week thereafter. Finally, we recorded the absolute thyroid weight and calculated the relative thyroid weight.At the end of the experiment, the rats were anesthetized using 50 mg/kg pentobarbital. Blood of rats in each group was collected from the abdominal artery, centrifuged , and then stored at −80°C for the following biochemical detection. The serum detection kit was purchased from Beijing Sino-UK Institute of Biological Technology ; the product numbers were as follows: T3 (no. HY-A0001), T4 (no. HY-A0002), FT3 (no. HY-A0004), FT4 (no. HYA0005), TSH (no. HY-A0003), thyrotropin-releasing hormone , thyroperoxidase , and thyroglobulin .The thyroid glands on both sides of the rat were taken out; the thyroid of one side was fixed with 4% paraformaldehyde, and the other side was immediately frozen in liquid nitrogen and stored at −80°C for gene and protein analysis. Tissues fixed with 4% paraformaldehyde were embedded in paraffin and sliced into 2 slices; one was stained with hematoxylin and eosin (H&E) to observe the pathological changes of the thyroid tissue, and the other one was identified by the TdT-mediated dUTP Nick-End Labeling (TUNEL) method for thyroid cell apoptosis .μg/μl, and the primer concentration was 10 μmol/μl. RT-PCR for each cDNA reaction system was performed with 20 μl liquid that contained 5 μl of double-distilled water, 10 μl of Power SYBR®Green Master mix, 0.5 μl of forward primer, 0.5 μl of reverse primer, and 4 μl of cDNA. The amplification reaction condition was 40 cycles of 95°C for 10 s and 55°C for 30 s. The relative quantitative levels of target mRNAs were calculated using the 2Ct)−. The cDNA was synthesized by using the Revert Aid First Strand cDNA Synthesis Kit . The cDNA concentration was 0.03 µg of protein extracted from the tissue was denatured in boiling water for 15 minutes, separated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and then transferred to the polyvinylidene difluoride (PVDF) membrane. Primary antibody p-ERK1/2 , ERK1/2 , and β-actin  were incubated in the membrane for 1 hour at room temperature. And, the secondary antibody  was incubated at room temperature for 1 hour. Protein levels were adjusted by β-actin. Phosphorylation levels were expressed as p-ERK1/2/ERk1/2 ratios.In this part of the experiment, the expression of p-erk1/2 protein in the thyroid tissue was detected. RIPA lysate, protease inhibitor, and phosphatase inhibitor were used to extract protein from tissues. 40 P < 0.05 was considered statistically significant.The results were presented as the means ± standard deviation. All statistical analyses were performed using SPSS software version 20.0 for Windows . The results were analyzed by one-way analysis of variance to examine the differences between groups. The previous research of our research group found that PTU can cause goiter in rats and change the structure of histology. At the same time, symptoms related to hypothyroidism appeared, serum thyroid hormone levels decreased, and TSH levels increased . In thisP < 0.05, P < 0.05, After 2 weeks of intragastric administration of PTU, serum T3, T4, FT3, and FT4 levels decreased and TSH increased, which indicated that the goiter model was successfully replicated. In this experiment, after PTU was administered intragastrically for two weeks, the serum levels of T3, T4, FT3, and FT4 in the model rats were markedly decreased , and the body weights of the three types of HDY treatment groups were not significantly different from the model group.In this experiment, we judged whether the rat had hypothyroidism symptoms by detecting the rat's general signs, body weight, rectal temperature, etc. and explored whether the drugs had therapeutic effects on the symptoms of hypothyroidism. During the experiment, the rats in the model group gradually developed a low metabolic state, such as coarse hair and slow reaction. The above symptoms were improved in each administration group. Changes in rectal temperature observed throughout the trial are shown in P < 0.05, Figures P < 0.05, P < 0.05), but there was no significant effect on the levels of FT3, FT4, and TSH. Compared with the model group, the levels of T3, T4, FT3, and FT4 in the HYD-U group increased significantly (P < 0.05) and the serum levels of TSH decreased (P < 0.05). Similarly, HYD-G also restored the reduction of FT3 and increment of TSH induced by PTU (P < 0.05), but the effect on FT3 was not as good as that of the HYD-U group (P < 0.05). HYD-1 showed a tendency to restore the serum levels of THs and TSH, although the difference was not significant. The serum TRH levels of rats in the model group were significantly higher than those in the control group , but there was no difference between them.In order to detect the effect of TCM drugs on thyroid function, we tested serum-related indicators. The results showed that compared with the control group, the serum T3, T4, FT3, and FT4 levels of the model group were significantly reduced (P < 0.05). Compared with the model group, three TCM administration groups significantly reduced the absolute thyroid weight and the relative thyroid weight (P < 0.05). However, there was no difference among the three TCM groups. In addition, the absolute thyroid weight of rats in the euthyrox group was significantly higher than that in the model group (P < 0.05).We judged the therapeutic effect of HYD on goiter by detecting the absolute and relative weight of the thyroid tissue. As shown in P < 0.05, P < 0.05) and the effect of HYD-I was not as good as that of HYD-U and HYD-G (P < 0.05). As for the diameter of thyroid follicular cell, it was increased in the model group compared with the control group , and HYD-I was superior to HYD-U (P < 0.05).In terms of structure, compared with the control group, the thyroid tissues of the model group and euthyrox group showed a lobular disordered structure, and the structure was unclear, the thyroid follicle endocrine was significantly reduced, the size was different, and the follicular epithelial cells were proliferated and showed hypertrophy. Nevertheless, after 28 days of treatment with HYD-U, HYD-I, and HYD-G, pathological changes of the thyroid tissue were alleviated . CompareP < 0.05). Furthermore, compared with the model group, the levels of TPO in the HYD-U group and HYD-I group were increased (P < 0.05). However, the elevated level of the HYD-U group was higher than that of HYD-G group (P < 0.05). The serum Tg level of rats in the model group was significantly higher than that in the control group  and the HYD-U group had better efficacy (P < 0.05). However, the serum levels of TPO and Tg in the euthyrox group had no significant difference from those of the control group and model group. According to the results of RT-qPCR analysis, we found that the mRNA levels of TPO expression in thyroid tissues in all groups had no statistical significance ; however, no significant difference was found among the three groups. Euthyrox significantly reduced the increase in the expression of Tg mRNA induced by PTU (P < 0.05).To explore whether HYD can reduce the degree of goiter by affecting the synthesis of thyroid hormone, we tested the serum levels of Tg and TPO and the levels of Tg, TPO, and Sodium Iodide Symporter (NIS) mRNA expression in thyroid tissues. As shown in P < 0.05) and the HDY-U group was the highest (P < 0.05).We investigated apoptosis-positive cells by TUNEL staining to determine whether the antigoiter of HYD was related to apoptosis. As shown in P < 0.05, Figures P < 0.05, P < 0.05), but the difference among these three groups was not statistically significant . Western blot analysis of p-ERK1/2 protein in thyroid tissues is shown in Figures P < 0.05). The three administration groups markedly decreased the protein level of p-ERK1/2 expression in the goiter model (P < 0.05); however, no significant difference was found among the three groups.The ERK pathway can promote cell proliferation. We examined the relevant indicators of the ERK pathway to study whether HYD could alleviate thyroid enlargement by inhibiting the ERK proliferation pathway. Compared with the control group, the mRNA expression levels of ERK1, ERK2, and RSK1 in the thyroid tissues of the model group were significantly increased  are combined with thyroxine-binding globulin (TBG) in a combined state and a small part of the THs (FT3 and FT4) are in a free state, and the combined state and the free state can be converted mutually. TSH is secreted by the anterior pituitary gland, and excessive TSH is the most important factor in stimulating thyroid proliferation. The HPT axis regulates the synthesis and secretion of THs [PTU is commonly used to treat hyperthyroidism. It inhibits the peroxidase system in the thyroid gland and prevents the synthesis of thyroid hormones (THs). In this study, we utilized PTU to establish a rat model of goiter with decreased serum TH level, increased TSH level, and decreased body metabolism. In our previous experiments, we have verified the feasibility of intragastric administration of PTU to replicate the goiter model , 11. Then of THs . TRH pro− ions is the first step [Tg is a large molecular glycoprotein secreted by thyroid follicular epithelial cells. It can be stimulated by TSH, is positively correlated with the size of the thyroid, and can be used as a marker of thyroid cancer . The synrst step , while Trst step . PTU is rst step –21. Abnorst step –24. In tUnder normal circumstances, cell proliferation and apoptosis are balanced. When the thyroid cell proliferation rate is much higher than the apoptosis rate, goiter appears . The mitWe also determined the contents of liquiritin, glycyrrhizic acid, forsythin, hesperidin, ferulic acid, and osthole in the three types of HYD. All these components have multiple pharmacological activities, and they all regulate cell proliferation or apoptosis. Liquiritin induced cell cycle arrest and apoptosis by inhibiting the MAPK/Akt/NF-κB signaling pathway . GlycyrrGlycyrrhiza uralensis had the best therapeutic effects in rats with goiter. Antigoiter effect of HYD may function through the HPT axis, inhibit the expression of Tg and NIS genes, and regulate the synthesis of THs, thereby reducing the excessive stimulation of TSH in thyroid cells. The HYD also prevented goiter by promoting thyroid cell apoptosis and inhibiting the ERK/RSK1 pathway of cell proliferation. In addition, we will continue to investigate the detailed underlying mechanisms. Three types of HYD had different therapeutic effects in rats with goiter, which might be caused by the compatibility of different varieties of Glycyrrhiza and Sargassum. Whether the safety of combining Glycyrrhiza and Sargassum is related to Glycyrrhiza species remains to be further studied.In summary, this preliminary study indicated that three types of HYD had antigoiter effects. The antigoiter effects included reduction in the weight of the thyroid and alleviation of the pathomorphological changes of the thyroid tissue. However, the three HYDs had no significant differences in antigoiter effect. In addition, HYD-U was better than HYD-I and HYD-G at improving thyroid function, inhibiting the ERK/RSK1 pathway, and promoting thyroid cell apoptosis. In conclusion, HDY composed of


The geometrical features of nanofibers, such as nanomat thickness and the diameter of nanofibers, have a significant influence on the toughening behavior of composite laminates. In this study, carbon/epoxy laminates were interleaved with polysulfone (PSF) nanofibrous mats and the effect of the PSF nanomat thickness on the fracture toughness was considered for the first time. For this goal, the nanofibers were first produced by the electrospinning method. Then, double cantilever beam (DCB) specimens were manufactured, and mode-I fracture tests were conducted. The results showed that enhancing the mat thickness could increase the fracture toughness considerably (to about 87% with the maximum thickness). The toughening mechanism was also considered by presenting a schematic picture. Micrographs were taken using a scanning electron microscope (SEM). Carbon fiber-reinforced polymers (CFRPs) are among the most common composite laminates used in different industries, especially in the automotive and aerospace industries. Despite their advantages, such as a high specific strength and elastic modulus, they can be easily damaged under fatigue, impact, or other loading ,2,3,4. TUsing thermoplastics as additives in thermoset-based CFRPs is an attractive method for enhancing their fracture toughness ,12,13,14Up until now, the abilities of some polymeric nanofibers, such as polyvinylidene fluoride (PVDF) ,35,36,37As can be seen in these studies, considering the effect of mat thickness is important for gauging the toughening ability of nanofibers. Thus, in this study, the focus is on composite laminates toughened by polysulfone (PSF) nanofibers. Although there are some limited studies of this topic ,50,51,52® 3500 PSF was purchased from Solvay company  with the following properties: density, 1.24 g/cm3; melting point, 316–371 °C; tensile strength, 70.3 MPa (these data were obtained from Solvay’s website).Electrospinning is one of the most common methods for producing nanofibers. Conductive collectors, high voltage sources, and syringe pumps with Teflon tubes are the most important components of an electrospinning machine . In thisv/v). The prepared solution was then transferred to the electrospinning machine and the following parameters were set to produce a uniform 3 ± 3 μm-nanofibrous mat: applied voltage, 22 kV; feed rate, 1.2 mL/h; and the distance between the needle tip and the collector, 12 cm.N,N-Dimethylacetamide (DMAc) and acetone were supplied as the solvent. The polymeric solution was prepared using 23% wt/v of polysulfone with solvent ratios of DMAc to acetone  were stacked on each other. In the first step, 12 layers of prepreg were laminated, and a thin refractory Teflon layer was applied . An additional 1, 2, or 3 mats of PSF nanofibers (used as a toughening agent) were implanted between these layers. In the second step, another 12 layers were placed onto the initial layers to produce the final sample. The laminated plate was then vacuumed and placed in the autoclave for curing. The autoclave control system was set according to the datasheet provided for the 8552 epoxy . The heaIn this research, double cantilever beam (DCB) specimens were used to determine the mode-I interlaminar fracture toughness. The test method and specimen size were followed according to the ASTM D5528 standard [All the tests were conducted using an MTS-10 kN universal machine at a displacement control condition (rate of 1 mm/min). The machine was carefully calibrated before conducting the tests. The relative error of the load cell and the displacement of this machine were 0.86% and 1%, respectively.A paper ruler with a grid size of 1 mm × 1 mm was attached to the edge of the specimen for the delamination length measurements and for investigating the variation of the fracture toughness during crack propagation (plotting R-curve). A paper ruler was attached to the samples for investigating the variation of the fracture toughness during crack propagation and plotting the R-curve. In order to investigate the test’s repeatability, three specimens were considered for each type. The sample specifications and their abbreviations are listed in The load versus load point displacement curves are presented in ICG):crδ is the displacement corresponding to 0a is the initial crack length (40 mm), B is the specimen width (25mm), and ∆ is the crack length calculated according to the suggestion in ASTM D5528 [According to the ASTM-D5528 standard [crδ, the average ICG increased by about 6%. Increasing one more layer of PSF between the laminate had a significant effect on the maximum load and fracture toughness and enhanced the ICG by about 41%. In the last modified sample (PSF-III), increasing the nanofibrous mat thickness led to an enhancement of the interlaminar fracture toughness (by about 87%). The interesting fact in this is the difference between the various polymeric nanofibers and how their thickness influences ICG. Brugo et al. [ICG increased by 42% and 98% by using the thin and thick membranes in comparison with the reference laminate, respectively. Unlike the above results, the effect of the thickness increase of the PVB nanofibers did not enhance the fracture toughness [o et al.  used 40 o et al. . The outoughness . Kheirkhoughness  applied The variation of the fracture toughness during the crack propagation is illustrated in ICG. 3. The local plastic deformation of the epoxy can be observed next to the PSF particles  nanofibers are among the most suitable choices for this aim. The influence of mat thickness  on mode-I fracture toughness was considered in this study. By conducting tests and investigating the fractured surfaces by SEM, the following conclusions were drawn:


Antimicrobial resistance (AMR) is an emerging public health crisis in Uganda. The World Health Organization (WHO) Global Action Plan recommends that countries should develop and implement National Action Plans for AMR. We describe the establishment of the national AMR program in Uganda and present the early microbial sensitivity results from the program.The aim of this study is to describe a national surveillance program that was developed to perform the systematic and continuous collection, analysis, and interpretation of AMR data.A systematic qualitative description of the process and progress made in the establishment of the national AMR program is provided, detailing the progress made from 2015 to 2020. This is followed by a report of the findings of the isolates that were collected from AMR surveillance sites. Identification and antimicrobial susceptibility testing (AST) of the bacterial isolates were performed using standard methods at both the surveillance sites and the reference laboratory.Escherichia coli, Klebsiella pneumoniae, and Neisseria gonorrhoeae) and gram-positive (Staphylococcus aureus and Enterococcus sp) bacteria with AST showed resistance to each of the tested antibiotics.Remarkable progress has been achieved in the establishment of the national AMR program, which is guided by the WHO Global Laboratory AMR Surveillance System (GLASS) in Uganda. A functional national coordinating center for AMR has been established with a supporting designated reference laboratory. WHONET software for AMR data management has been installed in the surveillance sites and laboratory staff trained on data quality assurance. Uganda has progressively submitted data to the WHO GLASS reporting system. Of the 19,216 isolates from WHO GLASS priority specimens collected from October 2015 to June 2020, 22.95% (n=4411) had community-acquired infections, 9.46% (n=1818) had hospital-acquired infections, and 68.57%  had infections of unknown origin. The highest proportion of the specimens was blood , followed by urine  and stool , whereas the lowest proportion was urogenital swabs . The mean age was 19.1 (SD 19.8 years), whereas the median age was 13 years (IQR 28). Approximately 49.13%  of the participants were female and 50.51%  were male. Participants with community-acquired infections were older  than those with hospital-acquired infections . All gram-negative (Uganda is the first African country to implement a structured national AMR surveillance program in alignment with the WHO GLASS. The reported AST data indicate very high resistance to the recommended and prescribed antibiotics for treatment of infections. More effort is required regarding quality assurance of laboratory testing methodologies to ensure optimal adherence to WHO GLASS–recommended pathogen-antimicrobial combinations. The current AMR data will inform the development of treatment algorithms and clinical guidelines. Antimicrobial resistance (AMR) is associated with increased morbidity and mortality and is recognized as an emerging global health threat. If left unchecked, by 2050, AMR may contribute up to 10 million deaths per year ,4. A sysStaphylococcus aureus and gram-negative organisms in different sample types has been reported [In Uganda, early efforts against AMR identified the critical gap as a lack of routine surveillance systems with limited data, making it difficult to track the AMR burden . Moreovereported . Anotherreported . This inreported . In addireported ,11.In 2015, the WHO launched the Global Laboratory AMR Surveillance System (GLASS) and initiated its implementation in the human health sector . The GLAIn line with global calls to enhance support for AMR systems in LMICs, development partners are currently supporting Uganda’s national laboratory system and, more recently, the National Action Plan (NAP) for AMR  using a In this paper, we highlight the progress on the implementation of GLASS in Uganda from October 2015 to June 2020 and describe laboratory-based AMR surveillance data obtained from selected surveillance sites in the same period. The data include corresponding participant characteristics (sex and age), source of bacterial infection for surveillance hospital-acquired infections (HAIs), bacterial recovery rates, and resistance profiles.Results section.A mixed methodology was used to obtain data presented in this study. Qualitative methods were used for the program setup, whereas quantitative methods were used to generate the AMR surveillance isolate data. A situational analysis report by the Uganda National Academy of Sciences was reviewed to understand the existing national AMR capacity and provide important information to guide program development . To deveIn 2015, Uganda responded to the WHO call for countries to enroll in the GLASS program. By enrolling in the GLASS program, Uganda committed to collecting and sharing national AMR surveillance data. As part of this process, the country also acquired the WHONET software  used to The National Coordinating Center (NCC) at the MoH has been set up to oversee the national AMR surveillance program in human health, including the collection and aggregation of data from surveillance sites. The NCC works in collaboration with the Uganda National AMR Sub-Committee (UNAMRsC) of the One Health approach to provide strategic oversights of the national AMR program. The UNAMRsC has also been established as part of the governance structure for AMR in the country. The membership of the UNAMRsC also includes representation from other relevant line ministries, such as animal health, wildlife, and the environment. The mandate of the UNAMRsC includes defining the national AMR surveillance objectives; developing and disseminating protocols; coordinating data collection, analysis, and reporting; and reviewing data before reporting to GLASS. To date, the NCC has supported the development of key AMR surveillance documents, including national AMR surveillance plans, protocols, guidelines, curricula, and microbiology standard operating procedures.The WHO requested all member countries to develop multisectoral-wide NAPs that are aligned with the Global Action Plan for AMR to support the implementation of the national AMR programs. Working with partners, the UNAMRsC completed the development of the Uganda AMR NAP , which wInitially, the Department of Medical Microbiology Laboratory at Makerere University was designated as the AMR Surveillance Laboratory. However, the capacity of the Central Public Health Laboratories has been built gradually, and it is now the designated national microbiology reference laboratory for AMR surveillance. The capacity built at Central Public Health Laboratories includes human resource development, quality management systems toward accreditation, isolate transportation, enhanced biorepository, and enrollment of laboratories in an External Quality Assurance scheme. In addition, the state-of-the-art Becton and Dickson–manufactured equipment, including matrix assisted laser desorption/ionization time of flight  and PhoeIn 2016, the AMR NCC designated different facilities as AMR surveillance sites. The sites were selected to ensure a balanced geographic, demographic, and socioeconomic distribution. They offer both outpatient and inpatient services, as per GLASS recommendations. However, the capacity of health facilities to conduct AMR surveillance varied between the different health facilities. As a result, selected sites have reported AMR surveillance data to the WHO and the capacity of the surveillance sites has been gradually developed. The Medicines and Therapeutics Committees oversee the implementation of the AMR surveillance program at the surveillance sites, which have been trained in collecting, analyzing, and reporting epidemiological, clinical, and laboratory data. The Medicines and Therapeutics Committee is usually headed by a senior consultant  who leads the stewardship of the AMR program at the site. On the basis of the clinician’s request for bacterial ID and AST as part of patient care, samples are collected according to the clinical protocols appropriate for the clinical presentation of patients and sent to the microbiology laboratory. The samples mainly include blood, urine, stool, and urogenital swabs and are accompanied by a microbiology laboratory request form that captures epidemiological information such as patient demographics and clinical presentation. The bacterial ID and AST data in this report were collected from 10 surveillance site microbiology laboratories between October 2015 and June 2020. The surveillance sites included Department of Medical Microbiology, Mbarara University of Science and Technology, Arua RRH, Kabale RRH, Mbarara RRH, Mubende RRH, Fort Portal RRH, Hoima RRH, Jinja RRH, Mbale RRH, and Soroti RRH . The sur2-enriched humid conditions. ID of gonococci colonies was based on the growth of the colonies with typical morphology in the modified Thayer Martin medium with a positive oxidase test [In the laboratory, bacterial ID and AST for the different samples were collected, and subsequently isolates were performed in accordance with the standardized microbiology protocols and standard operating procedures. Blood culture vials were placed in a BACTEC 9050 or FX40 blood culture system (Becton-Dickinson) according to the manufacturer’s instructions. Samples from flagged positive vials were subjected to Gram staining and then cultured on blood agar, chocolate agar, and MacConkey agar culture plates. The culture plates were incubated for 18 to 24 hours at 35°C to 37°C, with recovered colonies undergoing conventional biochemical testing to confirm ID. For stool samples, a loop full of emulsified sample was inoculated on deoxycholate citrate agar, or Xylose Lysine Deoxycholate agar, and MacConkey agar and incubated at 35°C to 37°C in ambient air for 18 to 24 hours. Isolation and ID of growth was performed using conventional methods. Urine samples were gently mixed and inoculated on MacConkey agar and blood agar using an appropriate calibrated loop and incubated in ambient air overnight for 18 to 24 hours at 35°C to 37°C. Isolation, conventional ID, and colony counting were performed where applicable. Both urine and stool were examined macroscopically and microscopically (Gram staining). All urogenital swabs were inoculated on selective modified Thayer Martin and nonselective chocolate agar culture plates and then incubated at 35°C to 37°C in 5% COase test . AST wasase test . PrelimiAll laboratory results , patient demographics, and clinical data were entered into the microbiology register. These data were then entered into the WHONET software program  on a weeP values based on chi-square tests were calculated for each variable to provide a sense of differences in demographic characteristics among different origins. For each specimen type, the percentage recovery for all bacterial pathogens and GLASS priority pathogens was expressed as the proportion of samples with a positive culture result out of the total samples cultured. Similarly, for each pathogen, resistance was expressed as the proportion of isolates with resistant or intermediate results out of the total number of isolates tested for susceptibility to a specific antibiotic. The binomial 95% CIs for the proportions of recovery and resistance were calculated using the Wilson method. The frequency of infection with resistant pathogens could not be calculated because data on the population at risk were unavailable. In addition, because of potential sampling bias, no statistical analysis was performed to identify any associations or risk factors for the occurrence of resistant pathogens. The analysis was performed using Excel (Microsoft), R version 3.6 , and WHONET.Summary statistics were calculated for key demographic characteristics of participants from whom samples were collected and stratified by the origin of the samples. Age was summarized as a continuous variable and categorized with age groups defined. Of the 19,216 participants involved in the surveillance program, 22.95%  had community-acquired infections, 9.46%  had HAIs, and 68.57%  had infections of unknown origin . The meaA total of 19,216 WHO GLASS priority specimens were collected for microbiological testing from 10 surveillance sites over a period of 4 years and 6 months, from October 2015 to June 2020. The highest proportion of the specimens was blood , followed by urine  and stool , whereas the lowest proportion was that of urogenital swabs .Escherichia coli , followed by S aureus , with the lowest being Acinetobacter baumannii .The overall recovery rate of the GLASS priority pathogens from the GLASS priority specimens was 7.4%  resistance to ceftriaxone, 18.8% (95% CI 14.9%-23.4%) resistance to imipenem, and 52% (95% CI 47.5%-56.6%) resistance to ciprofloxacin. High resistance of Klebsiella pneumoniae was noted among the commonly used antibiotics. High resistance of N gonorrhoeae was noted among the commonly used antibiotics, with 10% (95% CI 1.8%-40.4%) resistance to ceftriaxone and 71.4% (95% CI 45.4%-88.3%) resistance to ciprofloxacin. High resistance of Salmonella and Shigella was noted among the commonly used antibiotics, including resistance to meropenem, ceftriaxone, and ciprofloxacin.Resistance patterns for the most commonly isolated gram-negative bacteria, that is, S aureus was noted among the commonly used antibiotics, with 42.9% (95% CI 28%-59.1%) resistance to cefoxitin, 30.9% (95% CI 21.2%-42.6%) resistance to oxacillin, 76.9% (95% CI 69%-83.2%) resistance to TMP-SMX, and 15.5% (95% CI 9.6%-24%) resistance to vancomycin  resistance to ciprofloxacin and 50% (95% CI 33.6%-66.4%) resistance to vancomycin. A high resistance of Streptococcus sp was noted between vancomycin and ceftriaxone.Among gram-positive bacteria, high resistance of ncomycin . High reThe findings of our surveillance program show the feasibility of setting up a national AMR surveillance program based on the WHO GLASS manual recommendation while building systems for quality assurance, data sharing, linking results to patient care, and building partnerships. AMR is a global health threat, and the establishment of national surveillance systems is necessary to identify the emerging drug-resistant infections . The AfrThe success of establishing the national AMR surveillance program in Uganda highlights the feasibility of implementing the WHO GLASS program in LMICs. AMR surveillance programs are fundamental in Sub-Saharan African countries such as Uganda for generating antibiograms that can inform the development of treatment guidelines and antibiotic procurement plans and contribute toward standardized reporting ,26. ClinIn Uganda, the AMR surveillance system has been established using a systematic capacity-building pyramid model  and in aE coli, S aureus, K pneumoniae, and N gonorrhoeae, which present a high diversity of pathogens seen in Central Africa, Gabon [E coli and S aureus isolates were the most prevalent WHO priority pathogens isolated in Uganda. This is fundamental baseline information that could be used for pretesting the novel WHO protocol [The Uganda surveillance program identified selected resistant priority pathogens, including a, Gabon . E coli protocol  for estiprotocol .E coli to ampicillin and cotrimoxazole, as recently reported [E coli was slightly lower than that observed in Equatorial Guinea [E coli resistance to imipenem, which is considerably higher than 3%, recently reported in other parts of the African continent [K pneumoniae, there was notable resistance to ceftriaxone at 79% (63/79) and cotrimoxazole at 82% (55/67) in the surveillance program, similar to findings in Uganda’s neighboring country Kenya [There was a high rate of resistance of reported . Howeverl Guinea . More wory Kenya .To our knowledge, this is the first documentation of the implementation of a national AMR surveillance program on the African continent using the WHO-recommended methodology. Although all components of the WHO GLASS manual are implemented, the approaches were not sequential and were contextualized to Uganda cognizance of existing national policies and programs.The main limitations included suboptimal recovery of the AMR GLASS priority pathogens and inconsistent setting of the recommended antibiotics against the pathogen in the laboratory. This was attributed to the fact that staff members were still undergoing comprehensive training on microbiology skills, stock-outs, and acquiring extensive knowledge on AMR surveillance . The numUsing the WHO guidance, Uganda has successfully completed key foundational building activities for the successful implementation of a national AMR surveillance program. The emerging antibiotic resistance data can be refined, appraised, and used for further improvement of the current methodological approaches being used to implement AMR programs in Uganda and other LMICs. Uganda successfully enrolled in the WHO GLASS system and has consistently reported annual program progress to the WHO since 2016. There is an extremely high prevalence of AMR to the most commonly used antibiotics, similar to what has been found in other studies conducted in the research context.The current Uganda Clinical Guidelines need to be reviewed in response to the AMR burden in Uganda. In addition, strengthening the capacity of the microbiology laboratory is fundamental for the successful implementation of surveillance protocols in hospital wards to further profile the emerging global health threat of AMR.


The electrospinning and polymer blend solution conditions were optimized to produce thermally stable, smooth lignin-based nanofibers with total polymer content of up to 20 wt % in solution and a 50/50 blend weight ratio. Microscopy studies revealed that AL blends possess good solubility, miscibility, and dispersibility compared to LSL blends. Despite the lignin content or type, rheological studies demonstrated that PAN-MA concentration in solution dictated the blend’s viscosity. Smooth electrospun nanofibers were fabricated using AL depending upon the total polymer content and blend ratio. AL’s addition to PAN-MA did not affect the glass transition or degradation temperatures of the nanofibers compared to neat PAN-MA. We confirmed the presence of each lignin type within PAN-MA nanofibers through infrared spectroscopy. PAN-MA/AL nanofibers possessed similar morphological and thermal properties as PAN-MA; thus, these lignin-based nanofibers can replace PAN in future applications, including production of carbon fibers and supercapacitors.Lignin macromolecules are potential precursor materials for producing electrospun nanofibers for composite applications. However, little is known about the effect of lignin type and blend ratios with synthetic polymers. This study analyzed blends of poly(acrylonitrile- Many of today’s leading industries—such as aerospace, automobile, military, and energy—are increasingly pursuing sustainable materials with enhanced properties, including low density, good thermal stability, corrosion resistance, and high stiffness and strength. These performance enhancements traditionally have been achieved by using composite materials, most notably carbon fiber composites, offering an alternative to denser and more expensive metallic and ceramic material ,2. CommeAs recently demonstrated through scale-up processes, electrospinning has emerged as a viable tool in the manufacturing of natural nanocomposite fibers ,16,17,18The rheological, electrical conductivity and surface tension of polymer solutions heavily influence the morphological properties of electrospun nanofibers . For insco-MA copolymer blended with lignin fillers could produce stable nanofibers. Furthermore, the quality and spinnability of nanofibers are also governed by lignin type. Lignins are classified by their extraction methods and also on the plant resource such as organosolv lignin, alkali, Kraft lignin, and lignosulfonates.PAN homopolymers, blended with lignin, are the traditional precursor materials for the preparation of carbon nanofibers through electrospinning as discussed recently ; howeverco-MA rather than with pure PAN. We prepared PAN-co-MA/lignin blends at different weight ratios (50/50 and 80/20) and total polymer content  in DMF solvents for each lignin type. Using these polymers and blends, for the first time, we investigated the correlations between the polymer solution behavior  with the fabricated electrospun nanofibers morphological, thermal, and chemical properties. Furthermore, we discussed the effects of lignin sulfonation by using LSL and AL in the preparation and characterization of lignin-based electrospun nanofibers through microscopy, thermal, and spectroscopy analyses.The current study intends to shed light on the potential for producing thermally stable, uniform nanofibers from blends of the most common types of commercially available lignin, i.e., low sulfonate lignin (LSL) and alkali, kraft lignin (AL), with the copolymer PAN-co-methyl acrylate) with acrylonitrile ~94 wt %, MW 100,000 was procured from Scientific Polymer Products, Inc. . Hereafter, the copolymer is referred to as PAN-MA. Chemicals were used as received, without further purification.Alkali Lignin, low sulfonate content (LSL), alkali, kraft lignin (AL), and N,N-Dimethylformamide (DMF) anhydrous, 99.8% were purchased from Sigma-Aldrich . Poly  at 60 °C for 6 h to evaporate the residual DMF solvent after the electrospinning process.Each prepared polymer blend was filled transferred a 10 mL plastic syringe with a blunt 18G needle (~1 mm inner diameter) and mounted on a syringe pump . Electrospinning was conducted at a 0.003 mL/min flow rate. A voltage generator  was operated at 15 kV using a positive voltage supplied to the needle. A negative voltage (6–8 volts) was used to control a rotatory cylindrical drum collector . Electrospun nanofibers were collected on aluminum foil. The working distance between the collector and the needle was fixed at 21 cm. Fabricated nanofibers were heat-treated in a vacuum oven (Fisher Isotemp−1. Frequency sweep tests in oscillation mode were conducted using the same cone & plate geometry in the range of 100–0.1 rad/s (strain amplitude 1%) at 25 °C. All measurements were collected within the linear viscoelastic regime (LVE) of each sample. The distribution of LSL and AL nanofibers within the PAN-MA polymer solution were macroscopically analyzed with polarized optical microscopy using a polarized light microscope (Zeiss AX10 with Axio Cam HRc). To analyze lignin distribution within dried PAN-MA/lignin films, a film solvent casting approach was used. The films were prepared by placing each polymer solution on a glass microscope slide followed by solvent evaporation at 60 °C for 12 h in an oven. The films were examined with the same microscope and also with a scanning electron microscope  with an operating voltage of 5 kV or 15 kV.The polymer blends’ rheological behavior was determined at room temperature (25 °C) using flow and frequency sweep tests. These measurements were conducted using an Anton Paar MCR 302 modular compact rheometer equipped with a cone  and plate fixture. Using flow sweep tests, the shear rate varied between 1–1000 s−1 range using a Smart Golden Gate ZnSe ATR accessory. The thermal stability of each sample was evaluated using Thermogravimetric analysis . Thermograms were obtained using 4 mg samples heated on a platinum pan at a heating rate of 10 °C/min from 30 to 800 °C under a nitrogen atmosphere. Each thermogram was normalized with 100% weight percentage at ~130 °C to remove solvent effects . Thermal transitions—glass transition temperature (Tg), melting temperature (Tm) and crystallization temperature (Tc)—were identified for each electrospun nanofiber via Differential Scanning Calorimetry (DSC) and Modulated Differential Scanning Calorimetry (mDSC) experiments using a Q2000 instrument (TA Instruments). Samples were placed in hermetically sealed T-zero low mass aluminum pans for DSC and mDSC measurements with sample weights between 1–3.5 mg. DSC measurements were made while heating each sample from 40 to 400 °C with a heating rate of 10 °C/min while mDSC measurements were performed at 2°/min, 1 °C amplitude, and 60 s periods up to 200 °C. All tests were performed under an inert nitrogen atmosphere.The electrospun nanofibers’ morphology and diameter were examined using scanning electron microscopy  with an operating voltage of 15 kV and a high-resolution SEM (Hitachi S-4800) at an operating voltage of 30 kV. The mean diameter and standard deviation of the nanofiber thickness were estimated from the average of at least 50 measurements using ImageJ software. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectra were collected using a Nicolet iS50 instrument (Thermo Scientific). A minimum of 64 scans were collected for all spectra recorded in the 4000–500 cmPAN-MA/lignin polymer weight ratios were selected for electrospinning after a thorough microscopy inspection of solvent cast films . In a prPreliminary PAN-MA/LSL solvent evaporated films were obtained; however, phase separation was observed for short mixing times. Upon further inspection, an overnight mixing step (12 h) was implemented to improve the low-sulfonate lignin’s dispersion within the PAN-MA films. The additional mixing time significantly improved lignin dispersion for an 80/20 PAN-MA/LSL content, as shown in The viscosity results for the PAN-MA/lignin solutions are shown in −1 , was approaching 0.1 s−1; therefore, the flow behavior during electrospinning was considered to be Newtonian for all samples. Frequency sweep tests in oscillation mode confirmed the polymer solutions’ liquid-like behavior at different lignin concentrations and total polymer concentrations. At angular frequencies below 100 rad/s, G’’ > G’ for all the samples  exhibited the highest viscosity of all samples and resulted in a stable jet during electrospinning and defect-free continuous nanofiber mats as shown in As the polymer content increased, AL-3 and AL-4 fibers were observed to have a continuous, smooth fiber surface F,G, refe−1 for the appearance of sharkskin [In the industrial processes of polymer extrusion and fiber spinning, complex fiber morphologies such as sharkskin and melt fracture have been observed for pure polymers extruded at high shear rates, in some cases as low as 69 sharkskin . The pheharkskin  and highharkskin . HoweverThe purpose of TGA testing was to evaluate the decomposition behavior of the various powders and electrospun nanofiber materials, with a focus on how the material converts to a char which is important for the production of carbon fibers. First, the individual responses of the three raw materials in powder form are given in The TGA results for AL-containing electrospun nanofibers are given in The TGA results for LSL-containing fibers are shown in A comparison of the weight loss curves for all five fibers is offered in g value(s) for a polymer blend can often be used to infer information about the phase behavior, i.e., whether the blend is homogeneous  or heterogeneous . The DSC results for the powders are given in Differential Scanning Calorimetry (DSC) was used to further study the decomposition behavior of the blends at the relatively low end of the spectrum (T < 400 °C), as well as to measure the glass transition temperature of the blends . Generalg results, the curves were enlarged and offset vertically to give g of each material. Therefore, modulated DSC (mDSC) was conducted to help resolve these values, as given in g around 97 °C. There was no apparent shift with the AL-containing fibers relative to pure PAN-MA, while the LSL containing fibers exhibited a 1 or 2 °C shift to higher temperatures . Surprisingly, no indication of a glass transition was observed for the MA or LSL component of the blend, which was expected to occur around 140 °C based on the results of the pure powders . Broad -OH (~3300 cm−1) and CH2 stretching (2930 cm−1) peaks are typically found in lignin samples [−1 for both electrospun lignin fibers (AL-1 and LSL-1). This shift is attributed to potential interactions between lignin and PAN-MA [−1, characteristic for lignin, was also found in both PAN-MA/lignin electrospun nanofibers. Compared to the samples’ powder IR spectra, a red shift from 1267 cm−1 to 1260 cm−1 was observed only for the AL-1 blend; however, this shift was not observed for the LSL-1 sample. This finding supports that AL compatibility with PAN-MA is superior as compared to PAN-MA/LSL blends, confirming microscopy observations.FTIR analyses of PAN-MA/lignin electrospun nanofibers were undertaken to confirm the presence of lignin and to gain insights into lignin and PAN-MA interactions.  samples , and werd PAN-MA . The C-OIn this study, we demonstrated the successful production of electrospun nanofibers with the addition of alkali, Kraft lignin (AL) to PAN-MA at blend ratios of up to 50 wt % with a total polymer content up to 20 wt % in DMF solvent. These nanofibers exhibited PAN-MA/AL compatibility, a smooth morphology, and nanofiber diameters in the sub-micron scale region, as confirmed via microscopy and infrared spectroscopy measurements. As compared to neat PAN-MA, AL presence did not affect the fibers’ glass transition temperature (~97 °C) and did not affect the char yield (~47%) when heated in nitrogen to 800 °C. For PAN-MA/lignin blends, we found a minimum viscosity threshold of ~0.3 Pa-s to produce smooth electrospun nanofibers without a nodular morphology, independently of the lignin type. For LSL, however, we found poor compatibility with PAN-MA, which resulted in polymer phase separation, electrospun nanofibers with a nodular morphology, and polymer solutions prone to electrospraying. Ultimately, the degree of lignin sulfonation dictates the properties of high-quality lignin-based electrospun nanofibers. We conclude that PAN-MA/AL nanocomposite fibers could replace PAN or PAN-MA as precursors to producing carbon fibers or directly in other applications such as membranes, absorbents, supercapacitors, or electrical materials.