Changes In Absolute Values Research Articles

The Relation of Diabetes Complications to a New Interpretation of Glycaemic Variability from Continuous Glucose Monitoring in People with Type 1 Diabetes.

Microvascular and macrovascular complications in type 1 diabetes (T1D) may be linked to endothelial stress due to glycaemic variability. Continuous glucose monitoring systems (CGMs) provide new opportunities to quantify this variability, utilising the amplitude of glucose change summated over time. The aim of this study was to examine whether this determination of glucose variability (GV) is associated with microvascular clinical sequelae. Continuous glucose monitoring values were downloaded for 89 type 1 diabetes mellitus (T1D) individuals for up to 18 months from 2021 to 2023. Data for patient demographics was also taken from the patient record which included Sex, Date of Birth, and Date of Diagnosis. The recorded laboratory glycated haemoglobin (HbA1c) test results were also recorded. The glucose management index (GMI) was calculated from average glucose readings for 18 months using the formula GMI (%) = (0.82-(Average glucose/100)). This was then adjusted to give GMI (mmol/mol) = 10.929 * (GMI (%) - 2.15). Average Glucose Fluctuation (AGF) was calculated by adding up the total absolute change value between all recorded results over 18 months and dividing by the number of results minus one. The % Above Critical Threshold (ACT) was calculated by summing the total number of occurrences for each result value. A cumulative 95% limit was then applied to identify the glucose value that only 5% of results exceeded in the overall population. Using this value, we estimated the percentage of total tests that were above the Critical Threshold (ACT). Results for the 89 individuals (44 men and 45 women) were analysed over 18months. The mean age of participants was 43 years and the mean duration of diabetes was 18years. A total of 3.22 million readings were analysed, giving an average of 10.3mmol/L blood glucose. Those with the largest change in glucose from reading to reading, summated over time, showed the greatest change in eGFR of 3.12ml/min/1.73 m2 (p = 0.007). People with a higher proportion of glucose readings > 18mmol/L showed a fall in eGFR of 2.8ml/min/1.73 m2 (p = 0.009) and experienced higher rates of sight-threatening retinopathy (44% of these individuals) (p = 0.01) as did 39% of individuals in the highest tertile of glucose levels (p = 0.008). Those individuals with T1D in the highest tertile of reading-to-reading glucose change showed the greatest change in eGFR. Those with a higher proportion of glucose readings > 18mmol/L also showed a fall in eGFR and experienced higher rates of sight-threatening retinopathy, as did people with higher mean glucose. Discussions with T1D individuals could reflect on how the percentage recorded glucose above a critical level and degree of change in glucose are important in avoiding future tissue complications.

Unveiling the Spectrum of Glucose Variability: A Novel Perspective on FreeStyle Libre Monitoring Data.

Since the introduction of insulin therapy, it has become apparent that type 1 diabetes (T1D) is accompanied by long-term microvascular and macrovascular complications. In the context of the many benefits of continuous glucose monitoring (CGM), there remain opportunities to study the large amount of data now available in order to maximise its potential in the endeavour to reduce the occurrence of diabetes tissue complications in the longer term. Continuous glucose monitoring values were downloaded for 89 type 1 diabetes mellitus (T1D) individuals for up to 18 months from 2021 to 2023. Data for patient demographics was also taken from the patient record which included Sex, Date of Birth, and Date of Diagnosis. The recorded laboratory glycated haemoglobin (HbA1c) test results were also recorded. The glucose management index (GMI) was calculated from average glucose readings for 18 months using the formula GMI (%) = (0.82-(Average glucose/100)). This was then adjusted to give GMI (mmol/mol) = 10.929 * (GMI (%) - 2.15). Average Glucose Fluctuation (AGF) was calculated by adding up the total absolute change value between all recorded results over 18 months and dividing by the number of results minus one. The % Above Critical Threshold (ACT) was calculated by summing the total number of occurrences for each result value. A cumulative 95% limit was then applied to identify the glucose value that only 5% of results exceeded in the overall population. Using this value, we estimated the percentage of total tests that were above the Critical Threshold (ACT). The mean age of the participants was 42.6years, and the mean duration of T1D was 18.4years. A total of 3.22 million readings were analysed, yielding an average blood glucose level of 10.3mmol/l and a GMI of 57.2mmol/mol. There was a strong correlation between GMI and measured HbA1c (r2 = 0.82). However, there were patients who had an above-critical threshold (ACT) of 4-10% at a GMI of 60mmol/mol or less. The percentage average value at the time of day (%AVTD) was applied to all blood glucose readings at each 15-min interval throughout the day, averaged over 18months. The %AVTD of GMI (overall average 57.2mmol/mol) increased after midday, dipped at 18:00, and peaked at 22:00. The %AVTD of AGF (overall average 0.60mmol/l) showed higher change rates after 09:00 declining at the end of the day. The %AVTD of ACT peaked at 22:00, with those having the highest %ACT showing an additional peak at 15:00. We have shown here that the percentage glucose results above 18mmol/l (top 5% of distribution) increased exponentially above 54mmol/mol HbA1c. The %AVTD is introduced as a useful measure. Our data indicate that over the 24-h period, improvement in metabolic control could be focussed on the afternoon and evening, when there are higher-than-average levels of GMI, a higher-than-average degree of glucose change, and higher-than-average risks of being above the critical threshold. In conclusion, a measure of glycaemic variation based on the amplitude of glucose change to a population mean could be used to provide valuable clinical insights into glucose change over a 24-h period.

ANALYSIS OF THE INFLUENCE OF EXTERNAL FACTORS ON THE DEFORMATION OF HIGH-RISE BUILDINGS IN THE PROCESS OF THEIR CONSTRUCTION AND OPERATION

During the construction and operation of high-rise buildings, their vertical axis changes its position in space. The greater the height of the structure, the greater the amplitude of oscillations. This causes problems of geodetic construction support and the need to monitor deformations during the operation of high-rise structures. In real conditions, part of the structures will be in the shade and their temperature will be lower than the structures that will be under the influence of solar radiation, the temperature of which will be much higher. Thus, the building will deform as a result of uneven thermal expansion, that is, it will bend. From DBN B.1.3-2:2010 "Geodesic works in construction". Also, during the geodetic provision of the construction and operation of high-rise buildings, changes in the temperature regime of building structures should be taken into account in connection with significant absolute values of changes in the geometric dimensions of the building as a result of thermal expansion, which significantly exceed the accuracy regulated by the regulatory document. The article examines and analyzes the influence of external forces on changes in the geometry of high-rise structures and focuses attention on solving the scientific problem of geodetic support for the construction and operation of modern high-rise structures under dynamic loads.

Early changes in cardiac troponin T and NT-proBNP levels in neonates receiving ECMO support: a single-center experience

ObjectiveThis study aimed to examine the changes in absolute value and decline rate of early serum cardiac troponin T (cTnT) and N-terminal pro b-type natriuretic peptide (NT-proBNP) in neonates who received veno-arterial (V-A) extracorporeal membrane oxygenation (ECMO) support therapy within the first week of life.MethodsWe retrospectively collected clinical data and laboratory test results of 18 neonates who underwent V-A ECMO support within one week of birth, from July 2021 to June 2023, using the electronic medical record system. These patients were categorized into survival and death groups. Comparative analyses of the absolute values and decline rates of cTnT and NT-proBNP were made between the groups at baseline, and at 24, 48, and 72 h post-ECMO initiation.ResultsOut of the 18 neonates, 12 survived (survival rate: 66.7%), while 6 succumbed. The survival group exhibited significantly lower absolute values of cTnT and NT-proBNP than the death group, and their decline rates were significantly higher. Notably, all neonates without an early decline in cTnT and NT-proBNP levels were in the death group.ConclusionThe early changes in the absolute value and decline rate of serum cTnT and NT-proBNP in neonates undergoing V-A ECMO may serve as predictors of their prognosis.

P119 The effectiveness of drug-induced immunosuppression using biologics and Janus-kinase inhibitors in improving fatigue in adults with rheumatoid arthritis: a systematic review of randomised controlled trials

Abstract Background/Aims Fatigue is a prominent and debilitating symptom. Many clinicians indicate that they may not assess fatigue frequently because there are no guidelines for fatigue treatment; thus, they feel unskilled to appropriately manage it. Previous evidence from a 2016 Cochrane review supported the use of biologics for fatigue among people with rheumatoid arthritis (RA). As of yet, this evidence has not been incorporated into management guidelines. Further, it is outdated and lacks data on newer drugs such as biosimilars and Janus-Kinase inhibitors (JAKis). We aimed to update the evidence on the effectiveness of biologics and JAKis for RA-fatigue, with a view to informing future guidelines. Methods Five electronic databases (Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL and PubMed) were systematically searched, from 2014 to present, for randomised controlled trials (RCTs) evaluating pharmacological interventions in adults with RA. Two reviewers contributed to the screening and analysis of the included papers, and any dispute was resolved through a comprehensive discussion. One reviewer then extracted the data and assessed methodological quality using the Cochrane Risk of Bias Tool. The effectiveness of treatments was determined by extracting change from baseline (CFB) data and/or the proportion achieving the minimal clinically important difference (MCID) in fatigue. Where only CFB data were provided, reviewers compared absolute change values against the relevant MCID to evaluate intervention superiority. Owing to data heterogeneity, a narrative synthesis approach was undertaken. Results A total of 43 RCTs and post hoc analyses were included. No eligible studies were found regarding biosimilars. Drug classes investigated included JAKis (n = 27), interleukin-6 inhibitors (n = 9), anti-CD-20 monoclonal antibody (n = 1), selective so-stimulation modulators (n = 2) and TNF inhibitors (n = 4). Of these studies, four were inactive placebo comparator studies, 33 were active placebo comparator studies (i.e. csDMARDs), and six were head-to-head comparator studies. Studies had a low to unclear risk of bias, perhaps due to the high number of post hoc analyses (n = 28, 65%). In total, 37 studies (86%) determined an advantage to using biologics/JAKis; five (12%) determined that treatment with biologics/JAKis was not superior to csDMARDs. The final study showed no meaningful improvement in fatigue from treatment or control. Conclusion Most studies showed that biologics/JAKis hold the potential for fatigue management. However, fatigue reporting was poor, and few studies focussed on fatigue as a primary outcome in post hoc analyses. Therefore, it is not clear whether these treatments may, in fact, be more effective in certain subgroups of patients, for example, those for whom fatigue is a significant problem. Accordingly, the development of treatment guidelines involving these therapies is currently unlikely. We propose that future clinical trials designating fatigue as a primary endpoint will be crucial to improving the establishment of guidelines to support fatigue management. Disclosure H.J. Ghadanfari: None. J.H. Humphreys: None. K.L. Druce: None.

Mathematical modelling of the influence of ACE I/D polymorphism on blood pressure and antihypertensive therapy

The angiotensin-converting enzyme (ACE) gene (ACE) insertion/deletion (I/D) polymorphism raises the possibility of personalising ACE inhibitor therapy to optimise its efficiency and reduce side effects in genetically distinct subgroups. However, the extent of its influence among these subgroups is unknown. Therefore, we extended our computational model of blood pressure regulation to investigate the effect of the ACE I/D polymorphism on haemodynamic parameters in humans undergoing antihypertensive therapy. The model showed that the dependence of blood pressure on serum ACE activity is a function of saturation and therefore, the lack of association between ACE I/D and blood pressure levels may be due to high ACE activity in specific populations. Additionally, in an extended model simulating the effects of different classes of antihypertensive drugs, we explored the relationship between ACE I/D and the efficacy of inhibitors of the renin–angiotensin–aldosterone system. The model predicted that the response of cardiovascular and renal parameters to treatment directly depends on ACE activity. However, significant differences in parameter changes were observed only between groups with high and low ACE levels, while different ACE I/D genotypes within the same group had similar changes in absolute values. We conclude that a single genetic variant is responsible for only a small fraction of heredity in treatment success and its predictive value is limited.

Analysis of the influence of external factors on the deformation of high-rise buildings in the process of their construction and operation

During the construction and operation of high-rise buildings, their vertical axis changes its position in space. The greater the height of the structure, the greater the amplitude of oscillations. This causes problems of geodetic construction support and the need to monitor deformations during the operation of high-rise structures. In real conditions, part of the structures will be in the shade and their temperature will be lower than the structures that will be under the influence of solar radiation, the temperature of which will be much higher. Thus, the building will deform as a result of uneven thermal expansion, that is, it will bend. From DBN B.1.3-2:2010 "Geodesic works in construction". Also, during the geodetic provision of the construction and operation of high-rise buildings, changes in the temperature regime of building structures should be taken into account in connection with significant absolute values of changes in the geometric dimensions of the building as a result of thermal expansion, which significantly exceed the accuracy regulated by the regulatory document. The article examines and analyzes the influence of external forces on changes in the geometry of high-rise structures and focuses attention on solving the scientific problem of geodetic support for the construction and operation of modern high-rise structures under dynamic loads.

Accuracy of cup placement and pelvic motion in total hip arthroplasty in the lateral decubitus position using a new computed tomography-based navigation system with augmented reality technology.

This study aimed to investigate the accuracy of cup position and assess the changes in pelvic tilt during primary total hip arthroplasty (THA) in the lateral decubitus position using a new computed tomography (CT)-based navigation system with augmented reality (AR) technology. There were 37 cementless THAs performed using a CT-based navigation system with AR technology in the lateral decubitus position and 63 cementless THAs performed using manual implant techniques in the lateral decubitus position in this retrospective study. Postoperative cup radiographic inclination and anteversion were measured using postoperative CT, and the proportion of hips within Lewinnek's safe zone was analyzed and compared between the two groups. The mean absolute values of navigation error were assessed. Intraoperative pelvic tilt angles were also recorded using navigation system. The percentage of cups inside Lewinnek's safe zone was 100% in the navigation group and 35% in the control group (p < 0.001). The mean absolute values of navigation error in inclination and anteversion were 2.9° ± 2.1° and 3.3° ± 2.4°, respectively. The mean abduction angle of the pelvis was 5.1° ± 4.8° after placing the patients in the lateral decubitus position and 4.1° ± 6.0° after cup placement. The mean posterior tilt angle was 6.8° ± 5.1° after placing the patients in the lateral decubitus position and 9.3° ± 5.9° after cup placement. The mean internal rotation angle was 14.8° ± 7.4° after cup placement. There were no correlations between the navigation error in inclination or anteversion and the absolute values of changes of the pelvic tilt angle at any phase. Although progressive pelvic motion occurred in THA in the lateral decubitus position, especially during cup placement, the CT-based navigation system with AR technology improved cup placement accuracy.

Comparison of the impact of orthodontic treatment on pulp volume in adolescents and adults

Objective: To compare the impact of orthodontic treatment on pulp volume in adolescents and adults. Methods: Cone-beam CT data of 62 patients undergoing orthodontic treatment at the Department of Orthodontics, Stomatological Hospital of Chongqing Medical University, from January 2019 to March 2022 were collected. Patients were divided into two age groups (31 patients in each group): adolescent group (aged 13-17, 17 males and 14 females) and adult group (aged 21-25, 12 males and 19 females). Pre-and post-treatment reconstructions of the pulp and dental tissues of upper first molars (UM1) and lower central incisors (L1) were performed. Measurements included pulp volume for UM1 (UM1 P) and L1 (L1 P), pulp chamber volume (UM1 PC) and root canal volume (UM1 RC) for UM1, root length for L1 (L1 RL), and mesiobuccal root length for UM1 (UM1 RL), as well as chamber heights at specific landmarks [the lengths from the central fossa fusion site to the roof of the pulp chamber (H1), the floor of the pulp chamber (H2), the nearest point of root divergence as well as crown-root bifurcation (H3), the farthest point of root divergence (H4), and the pulp chamber height (H5)] in UM1. Changes in these indices were calculated and analyzed using paired and independent sample t-tests for within-group and between-group differences, respectively. Pearson correlation was used to assess potential associations among H5, root length, and pulp volume changes. Results: Before and after orthodontic treatment, no significant difference was observed in the adult group for L1 P (t=-0.03, P=0.975), while significant differences were noted for UM1 P, UM1 PC, and UM1 RC (t=9.98, P<0.001; t=9.04, P<0.001; t=6.69, P<0.001). In the adolescent group, significant differences were found for both L1 P and UM1 P (t=2.25, P=0.029; t=6.30, P<0.001). After orthodontic treatment, the absolute value changes of UM1 P, UM1 PC, and L1 P in the adolescent group were (19.75±9.58), (15.07±7.65) and (1.89±6.29) mm3, respectively, and in the adult group were (13.33±9.41), (9.16±7.05) and (0.02±4.66) mm3, respectively (t=3.77, P<0.001; t=4.48, P<0.001; t=2.34, P=0.048). There was no significant absolute difference in the amount of UM1 RC between the two groups after orthodontic treatment (t=0.86, P=0.391). Before and after orthodontic treatment, the absolute value changes of L1 RL, H1 and H5 in the adolescent group were (0.54±0.41), (0.38±0.27) and (0.71±0.33) mm, respectively, and the absolute value changes in the adult group were (0.78±0.62), (0.26±0.20) and (0.57±0.28) mm, respectively (t=-2.43, P=0.017; t=2.96, P=0.004; t=2.57, P=0.011). Whereas no significant differences were observed for UM1 RL, H2, H3, and H4 (t=-0.85, P=0.400; t=0.43, P=0.669; t=-0.50, P=0.619; t=1.46, P=0.148). Additionally, significant correlations were found between changes in H5 and UM1 RL with UM1 P (r=0.35, P<0.001; r=0.19, P=0.030), but not between Changes in L1 RL and L1 P (r=0.11, P>0.05). Conclusions: The effect of orthodontic treatment on pulp volume in adolescents and adults were different.

Prognostic value of myocardial deformation parameters for outcome prediction in tetralogy of Fallot

BackgroundThe prognostic value of myocardial deformation parameters in adults with repaired tetralogy of Fallot (rTOF) has not been well-elucidated. We therefore aimed to explore myocardial deformation parameters for outcome prediction in adults with rTOF using cardiovascular magnetic resonance imaging (CMR). MethodsAdults with rTOF and at least moderate pulmonary regurgitation were identified from an institutional prospective CMR registry. Left ventricular (LV) and right ventricular (RV) global strains were recorded in longitudinal (GLS), circumferential (GCS), and radial (GRS) directions. Major adverse cardiovascular events (MACE) were defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia (>30 seconds), or heart failure (hospital admission >24 hours). In patients with pulmonary valve replacement (PVR), pre- and post-PVR CMR studies were analyzed to assess for predictors of complete RV reverse remodeling, defined as indexed RV end-diastolic volume (RVEDVi) <110 mL/m2. Logistic regression models were used to estimate the odds ratio (OR) per unit change in absolute strain value associated with clinical outcomes and receiver operator characteristic curves were constructed with area under the curve (AUC) for select CMR variables. ResultsWe included 307 patients (age 35 ± 13 years, 59% (180/307) male). During 6.1 years (3.3–8.8) of follow-up, PVR was performed in 142 (46%) and MACE occurred in 31 (10%). On univariate analysis, baseline biventricular ejection fraction (EF), mass, and all strain parameters were associated with MACE. After adjustment for LVEF, only LV-GLS remained independently predictive of MACE (OR 0.822 [0.693–0.976] p = 0.025). Receiver operator curves identified an absolute LV-GLS value less than 15 and LVEF less than 51% as thresholds for MACE prediction (AUC 0.759 [0.655–0.840] and 0.720 [0.608–0.810]). After adjusting for baseline RVEDVi, RV-GCS (OR 1.323 [1.094–1.600] p = 0.004), LV-GCS (OR 1.276 [1.029–1.582] p = 0.027) and LV-GRS (OR 1.101 [1.0210–1.200], p = 0.028) were independent predictors of complete remodeling post-PVR remodeling. ConclusionBiventricular strain parameters predict clinical outcomes and post-PVR remodeling in rTOF. Further study will be necessary to establish the role of myocardial deformation parameters in clinical practice.

The informative power of heart rate along with machine learning regression models to predict maximal oxygen consumption and maximal workload capacity

Prediction of maximal oxygen consumption (VO2max) and maximal workload capacity (MWC) through submaximal exercise tests is an important topic for sports sciences. Numerous studies highlighted the predictive power of submaximal heart rate (HR) and oxygen consumption (VO2) in predicting VO2max and MWC. The challenge is achieving the best possible precision and accuracy by identifying the best predictors and regression models. This project assessed the performance of different indexes along with machine learning regression models to estimate VO2max and MWC. Predictors consisted of biodata (age, weight, and height) along with different combinations of change-scores of HR and VO2 between 0–50 Watts, 50–65 Watts, and 65–80 Watts (Δ0–50, Δ50–65, and Δ65–80, respectively). The use of biodata + HR Δ50–65 + HR Δ65-80 via a Squared Exponential Gaussian Process Regression model resulted in the best performance in predicting VO2max, while the use of biodata + HR Δ0–50 via a Robust Linear Regression model resulted in the best performance in predicting MWC. These results suggest that information provided by HR only during submaximal exercise offers the best predictive mean for estimating VO2max and MWC, while the use of VO2 changes or its addition along with HR changes does not improve predictions. Moreover, different predictors need to be selected for the best estimation of VO2max and MWC. Change-scores refer to absolute value changes, providing information to develop athlete assessment protocols through standardized workloads. These results show practical applicability for sports assessments to be performed indirectly, rapidly, sub-maximally, and through the simple measurement of HR.

Paradoxical increase in global longitudinal strain by handgrip exercise despite left ventricular diastolic dysfunction.

Although global longitudinal strain (GLS) is recognized as a sensitive marker of intrinsic left ventricular (LV) dysfunction, its afterload dependency has also been pointed. We hypothesized that decrease in GLS during handgrip exercise could be more sensitive marker of intrinsic myocardial dysfunction. Handgrip exercise-stress echocardiography was performed in 90 cardiovascular disease patients with preserved LV ejection fraction. LV diastolic function was graded according to the guidelines. Diastolic wall stress (DWS) and ratio of left atrial (LA) volume index to late-diastolic mitral annular velocity (LAVI/a') were measured at rest as LV stiffness. As well, LA strains were measured to assess LA function. GLS was expressed as absolute value and significant changes in GLS by handgrip exercise was defined as changes over prespecified mean absolute test-retest variability (2.65%). While mean value of GLS did not change by the exercise, substantial patients showed significant changes in GLS: decreased (group I, n=28), unchanged (group II, n=34), and increased (group III, n=28). Unexpectedly, patients in group I did not show any clinical and echocardiographic characteristics, while those in group III were characterized by elevated natriuretic peptide levels, blunted heart rate response to handgrip exercise, and advanced LV diastolic dysfunction. Multivariable analyses revealed that DWS, left atrial booster strain, and grade II or more diastolic dysfunction determined the increase in GLS even after adjustment for elevated natriuretic peptides and the changes in heart rate by the exercise. In contrast to our hypothesis, paradoxical increase in GLS by handgrip exercise could be associated with advanced LV diastolic dysfunction in cardiovascular patients with preserved LV ejection fraction. Our findings suggest that HG exercise for heart failure patients does not enhance the afterload straightforward, resulting in variable changes of GLS according to the individual conditions.

Reserves of Calcium, Copper, Iron, Potassium, Magnesium, Manganese, Sodium, Phosphorus, Strontium and Zinc in Goose Egg Yolk during Embryo Development.

This study evaluated the changes in calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), strontium (Sr) and zinc (Zn) values in goose egg yolk during the incubation period. This study was conducted on a completely random selection using 200 fertile eggs from a local flock of geese. A selection of 30 fertile eggs were randomly sampled on days 0, 9.5, 19.5, 25 and 30 of incubation (total: 150 eggs), and the yolks of 5 eggs in each replicate were mixed together and considered as one replicate (six replicates in each incubation period). The mineral content of the yolks was measured using the inductively coupled plasma (ICP) spectroscopy method. The results of this study show that, during the incubation of goose eggs from 0 to 30 days of embryo growth, except for Ca, the yolk content (absolute weight) of all the measured minerals, including Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn, on day 30 of incubation were statistically significantly lower than on day 0 of incubation. Additionally, the yolk concentrations of Fe, K, Mg, Na, P and Zn declined, the yolk concentrations of Ca and Sr increased, and the yolk concentrations of Cu and Mn were unchanged on day 30 compared to the first day of incubation. The results of the current study demonstrate that goose egg yolks' mineral concentrations change in absolute value during the incubation period, which could be the basis for further studies on chick feeding during the embryonic and post-embryonic phases.

Association of CA19-9 and tumor size in treatment monitoring for patients with metastatic pancreatic ductal adenocarcinoma (PDAC).

693 Background: Although modern cancer treatment has significantly prolonged patient’s life, it comes with a high financial cost. Based on an NIH report on Financial Burden of Cancer Care, treating PDAC costs $108K, $18K, and $125K for initial treatment, during follow up, and in last year of life, respectively. Of these, CA19-9 and CT studies are obtained concurrently to evaluate tumor burden whose cost can be reduced by decreasing imaging frequency when CA19-9 remains stable. As a pilot study, we evaluated whether changes in CA19-9, an inexpensive laboratory study commonly used for monitoring treatment response, correlates with tumor size change on imaging studies. A positive correlation may lead us to design future studies to evaluate whether stable CA19-9 can serve as an indicator for stable disease on CT scan such that imaging frequency (and cost) may be reduced. Methods: We retrospectively identified PDAC patients from our tumor registry from 2016 to 2019. Subjects were included if they met the following criteria: 1) diagnosed with PDAC 2) had at least 2+ CA19-9 and CT/MR follow up assessments with the laboratory and imaging studies within one month of each other, and 3) had measurable lesions as defined by RECIST 1.1 criteria. Due to limited resources, we limited the maximum number of lesions to 4 instead of the usual 5 for RECIST 1.1. Two-dimensional orthogonal tumor sizes were measured on axial images with the largest cross-section. Changes in the values were obtained serially (from the immediately prior study). Nonparametric correlations (Spearman’s rho) were used to evaluate monotonicity. The significance level was set at p &lt; 0.05. Results: We screened 300 subjects from the tumor registry and identified 23 subjects suitable for our study. 13 subjects were female and 10 were male with ages ranging from 35 to 84. We identified 55 target lesions and 128 assessments (with both CA19-9 and imaging) from the 23 subjects. We analyzed the log absolute and log relative change in CA19-9 with change in tumor area. When absolute CA19-9 value, absolute change in CA19-9, and relative change in CA19-9 were tested against the absolute change in tumor size, the correlation was significant for the absolute value and absolute change of CA19-9 (p &lt; 0.01), but not for relative change of CA19-9 (p &lt; 0.11). When tested against relative change in tumor size, all three values were highly significant (p &lt; 0.001). Conclusions: Our finding of direct correlations between changes of CA19-9 and relative change of tumor size on imaging suggests that CA19-9 can serve as a surrogate measure of relative change of tumor burden for patients undergoing treatment. This provides motivation for future studies evaluating the possibility that stable CA19-9 can represent stable tumor burden such that expensive imaging studies may be obtained at longer time intervals to reduce financial cost to patients.

Aerosol Measurement Degradation in Low-Cost Particle Sensors Using Laboratory Calibration and Field Validation.

Increasing concern over air pollution has led to the development of low-cost sensors suitable for wide-scale deployment and use by citizen scientists. This project investigated the AirU low-cost particle sensor using two methods: (1) a comparison of pre- and post-deployment calibration equations for 24 devices following use in a field study, and (2) an in-home comparison between 3 AirUs and a reference instrument, the GRIMM 1.109. While differences (and therefore some sensor degradation) were found in the pre- and post-calibration equation comparison, absolute value changes were small and unlikely to affect the quality of results. Comparison tests found that while the AirU did tend to underestimate minimum and overestimate maximum concentrations of particulate matter, ~88% of results fell within ±1 μg/m3 of the GRIMM. While these tests confirm that low-cost sensors such as the AirU do experience some sensor degradation over multiple months of use, they remain a valuable tool for exposure assessment studies. Further work is needed to examine AirU performance in different environments for a comprehensive survey of capability, as well as to determine the source of sensor degradation.

Ocular blood flow and myopia

AbstractPurpose: It has previously been found that imposing positive defocus changes axial length and choroidal thickness after only 30 minutes. In the present study, we investigated whether these changes may result from an altered choroidal blood flow.Methods: Eighteen young adult subjects watched a movie from a large screen (65 inch) in a dark room at 2 m distance. A fifteen‐minute wash‐out period was followed by 30 minutes of watching the movie with a monocular positive defocus (+2.5D). Changes in axial length and ocular blood flow were measured before and after the defocus, by using low‐coherent interferometer (LS 900, Haag‐Streit, Switzerland) and a laser speckle flowgraphy (LSFG) RetFlow unit (Nidek Co., LTD, Japan), respectively. Three regions were analysed: (1) the macular area, where choroidal blood flow can be measured, (2) the optic nerve head (ONH), and (3) retinal vessel segments.Results: Changes in choroidal blood flow were significantly and negatively correlated with changes in axial length that followed positive defocus in exposed eyes (R = −0.67, p &lt; 0.01). The absolute values of changes in choroidal blood flow in the defocused eyes were significantly larger than in the fellow control eyes. ONH and retinal blood flow were not associated with the induced changes in axial length.Conclusions: Positive defocus selectively alters choroidal, but not retinal or ONH blood flow in young human subjects after short‐term visual exposure. The results suggest that blood flow modulation is involved in the mechanism of choroidal responses to optical defocus.

Atmospheric Density Response to a Severe Magnetic Storm Detected by the 520 km Altitude Spherical Satellite

The polar-orbiting spherical experimental satellite of China for atmospheric density detection with an altitude of ~520 km was successfully launched on 14 October 2021. Based on the dynamic inversion method for atmospheric density and the precise orbit determination data obtained by its GNSS, we inverted the orbital atmospheric density during the severe geomagnetic storm in early November 2021. In this paper, we compared the atmospheric density data obtained by the spherical satellite with the simulations of the MSISE00 and the DTM, evaluated their error distribution, and analyzed the response of the atmospheric density during the severe geomagnetic storm in the dawn–dusk orbit of 520 km altitude. The properties and the physical processes for the atmospheric density of the time evolutions in different latitudes and the global distributions during the severe geomagnetic storm were obtained. We found that the substantial disturbance enhancement and recovery of the atmospheric density of the dawn–dusk orbit have a close correlation with the geomagnetic indexes Kp and Dst. The elevation extends from the poles to the equator, and the relative variation in two hemispheres demonstrates a bimodal nearly symmetric growth structure. The maximum relative variation of the two hemispheres both occurred in the middle latitude, and, for this case, the enhancement of atmospheric density in the mid-latitude region accounted for a larger proportion. The asymmetry between the northern and southern hemispheres is demonstrated by the fact that the absolute value and absolute change in the southern hemisphere in summer are larger than those in the northern hemisphere, and the bimodal structure of the relative variation is inclined to the northern hemisphere.

Influence of Mn2+ doping on refractive and electronic properties of β-LiNH4SO4 crystals

β-LiNH4SO4:Mn2+ crystals with 2 and 5 wt% Mn2+ concentration have been synthesized. The crystalline structure of impurity crystals was identified and refined by means of X-ray diffraction analysis. Experimentally studied dispersions of the refractive indices and birefringence showed that the introduction of the impurity leads to an increase in the absolute values of refractive indices without changing the nature of the dispersion; the anisotropy of the optical indicatrix increases along with a significant changes of birefringence absolute values. The optical birefringence temperature dependence reveals shifts in the phase transition point of the impurity crystals towards lower temperatures; the temperature interval of the existence of the “intermediate” phase in the β-LiNH4SO4:Mn2+ also shifts. The results of optical studies are independently confirmed by experimental studies of thermal expansion and differential thermal analysis. Band structure and optical spectra of β-LiNH4SO4:Mn2+ crystal are calculated using the density functional theory.

Imposed positive defocus changes choroidal blood flow in young human subjects

PurposeIt has previously been found that imposing positive defocus changes axial length and choroidal thickness after only 30 min. In the present study, we investigated whether these changes may result from an altered choroidal blood flow.MethodsEighteen young adult subjects watched a movie from a large screen (65 in.) in a dark room at 2 m distance. A 15-min wash-out period was followed by 30 min of watching the movie with a monocular positive defocus (+ 2.5D). Changes in axial length and ocular blood flow were measured before and after the defocus, by using low-coherent interferometer (LS 900, Haag-Streit, Switzerland) and a laser speckle flowgraphy (LSFG) RetFlow unit (Nidek Co., LTD, Japan), respectively. Three regions were analyzed: (1) the macular area, where choroidal blood flow can be measured, (2) the optic nerve head (ONH), and (3) retinal vessel segments.ResultsChanges in choroidal blood flow were significantly and negatively correlated with changes in axial length that followed positive defocus in exposed eyes (R = − 0.67, p < 0.01). The absolute values of changes in choroidal blood flow in the defocused eyes were significantly larger than in the fellow control eyes (2.35 ± 2.16 AU vs. 1.37 ± 1.44 AU, respectively, p < 0.05). ONH and retinal blood flow were not associated with the induced changes in axial length.ConclusionsPositive defocus selectively alters choroidal, but not retinal or ONH blood flow in young human subjects after short-term visual exposure. The results suggest that blood flow modulation is involved in the mechanism of choroidal responses to optical defocus.

Performance of Machine Learning and Texture Analysis for Predicting Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer with 3T MRI.

Background: To evaluate the diagnostic performance of a Machine Learning (ML) algorithm based on Texture Analysis (TA) parameters in the prediction of Pathological Complete Response (pCR) to Neoadjuvant Chemoradiotherapy (nChRT) in Locally Advanced Rectal Cancer (LARC) patients. Methods: LARC patients were prospectively enrolled to undergo pre- and post-nChRT 3T MRI for initial loco-regional staging. TA was performed on axial T2-Weighted Images (T2-WI) to extract specific parameters, including skewness, kurtosis, entropy, and mean of positive pixels. For the assessment of TA parameter diagnostic performance, all patients underwent complete surgical resection, which served as a reference standard. ROC curve analysis was carried out to determine the discriminatory accuracy of each quantitative TA parameter to predict pCR. A ML-based decisional tree was implemented combining all TA parameters in order to improve diagnostic accuracy. Results: Forty patients were considered for final study population. Entropy, kurtosis and MPP showed statistically significant differences before and after nChRT in patients with pCR; in particular, when patients with Pathological Partial Response (pPR) and/or Pathological Non-Response (pNR) were considered, entropy and skewness showed significant differences before and after nChRT (all p < 0.05). In terms of absolute value changes, pre- and post-nChRT entropy, and kurtosis showed significant differences (0.31 ± 0.35, in pCR, −0.02 ± 1.28 in pPR/pNR, (p = 0.04); 1.87 ± 2.19, in pCR, −0.06 ± 3.78 in pPR/pNR (p = 0.0005); 107.91 ± 274.40, in pCR, −28.33 ± 202.91 in pPR/pNR, (p = 0.004), respectively). According to ROC curve analysis, pre-treatment kurtosis with an optimal cut-off value of ≤3.29 was defined as the best discriminative parameter, resulting in a sensitivity and specificity in predicting pCR of 81.5% and 61.5%, respectively. Conclusions: TA parameters extracted from T2-WI MRI images could play a key role as imaging biomarkers in the prediction of response to nChRT in LARC patients. ML algorithms can be used to efficiently combine all TA parameters in order to improve diagnostic accuracy.