Comparison of Bioimpedance Versus Pulse Contour Analysis for Intraoperative Cardiac Index Monitoring in Patients Undergoing Kidney Transplantation

Background: Cardiac index (CI; cardiac output indexed to body surface area) is routinely measured during kidney transplant surgery. Bioimpedance cardiometry is a transthoracic impedance as the non-invasive alternative for hemodynamic monitoring, using semi-invasive uncalibrated pulse wave or contour (UPC) analysis. Objectives: We performed a cross-sectional observational study on 50 kidney transplant patients to compare the CI measurement agreement, concordance rate, and trending ability between bioimpedance and UPC analysis. Methods: For each patient, CI was measured by bioimpedance analysis (ICONTM) and UPC analysis (EV1000TM) devices at three time points: after induction, during incision, and at reperfusion. The device measurement accuracy was assessed by the bias value, limit of agreement (LoA), and percentage error (PE) using Bland-Altman analyses. Trending ability was assessed by angular bias and polar concordance through four-quadrant and polar plot analyses. Results: From each time point and pooled measurement, the correlation coefficients were 0.267, 0.327, 0.321, and 0.348. Bland-Altman analyses showed mean bias values of 1.18, 1.06, 1.48, and 1.30, LoA of -1.35 to 3.72, -1.39 to 3.51, -1.07 to 4.04, and -1.17 to 3.78, and PE of 82.21, 78.50, 68.74, and 74.58%, respectively. Polar plot analyses revealed angular bias values of -10.37º, -15.01º, -18.68º, and -12.62º, with radial LoA of 89.79º, 85.86º, 83.38º, and 87.82º, respectively. The four-quadrant plot concordance rates were 70.77, 67.35, 65.90, and 69.79%. These analyses showed poor agreement, weak concordance, and low trending ability of bioimpedance cardiometry to UPC analysis. Conclusions: Bioimpedance and UPC analysis for CI measurements were not interchangeable in patients undergoing kidney transplant surgery. Cardiac index monitoring using bioimpedance cardiometry during kidney transplantation should be interpreted cautiously because it showed poor reliability due to low accuracy, precision, and trending ability for CI measurement.

Comparison of surgically induced astigmatism between anterior and total cornea in 2.2 mm steep meridian incision cataract surgery

Background This study aimed to compare surgically induced astigmatism (SIA) on the anterior and total cornea during cataract surgery through a 2.2 mm steep meridian incision. Methods The study included 69 left eyes of 69 patients who had undergone cataract surgery. The 69 eyes were classified into three subgroups according to the preoperative steep meridian. Following phacoemulsification, an intraocular lens was inserted into the bag. The keratometric measurements were taken 12 months postoperatively, on the anterior cornea (automated keratometer and anterior keratometry [K] from a rotating Scheimpflug camera) and total cornea (equivalent K reading [EKR] 3.0 mm, EKR 4.5 mm, total corneal refractive power (TCRP) 2.0 mm ring, TCRP 3.0 mm zone, TCRP 4.0 mm zone). The SIA was analyzed for each parameter. Results On the double-angle polar plot, the summated vector mean values of SIA determined by the automated keratometer and Scheimpflug anterior K were 0.28 diopter (axis: 177°) and 0.37 diopter (axis: 175°) in with-the-rule (WTR) astigmatism; 0.03 diopter (axis: 156°) and 0.18 diopter (axis: 177°) in oblique astigmatism; 0.15 diopter (axis: 96°) and 0.17 diopter (axis: 73°) in against-the-rule (ATR) astigmatism. The mean SIAs on the total cornea ranged from 0.31 to 0.42 diopter in WTR astigmatism; from 0.16 to 0.27 diopter in oblique astigmatism; from 0.04 to 0.11 diopter in ATR astigmatism. Mean magnitude SIA ranged from 0.41 to 0.46 diopter on anterior corneal surface and 0.50 to 0.62 diopter on total cornea. J0 and J45 of the posterior cornea showed no significant changes after cataract surgery, and the changes in J0 and J45 did not show any statistical differences between the anterior and total cornea (all p > 0.05). Conclusions There were no differences in the summed vector mean values of SIA between the anterior cornea and the total cornea.

CFD Analysis on Aerodynamic Coefficients of Flying Saucer

With the growing of Unmanned Aerial Vehicle (UAV) usage, many new types of UAV are introduced. Flying Saucer is a new type of UAV which is not yet famous in the market. The aim of this study is to analysis the aerodynamic coefficients of a Flying Saucer. The research question arise is What the optimum angle of attack for Flying Saucer flight is. The study is conducted in Computational Fluid Dynamics (CFD) using COMSOL Multiphysics with Laminar Flow physics for several angles of attack. The analysis considers Lift and Drag coefficient in the form of 𝐶𝐿 and 𝐶𝐷 to angle of attack (α) plot, ratio of 𝐶𝐿/𝐶𝐷 to angle of attack (α) plot and drag polar plot. We conclude that a symmetric Flying Sauce has aerodynamic characteristic with the optimum operational angle of attack in the range of 8 to 16 deg. The 𝐶𝐷 and 𝐶𝐿 has a quadratic relationship with large 𝐶𝐷0 due to the geometric of Flying Saucer. It recommends that further study should explore in the area of zero and maximum angle of attack (α) and validation in wind tunnel experiment.

The Accuracy and Reliability of Cardiac Output Assessment by Measuring Descending Aortic Blood Flow in Patients Undergoing Cardiac Surgery

Background To investigate the accuracy and reliability of cardiac output (CO) assessment by transesophageal echocardiographic (TEE) measuring descending aortic blood flow (DABF) in patients undergoing cardiac surgery under cardiopulmonary bypass (CPB). And the influence of DABF/CO on the accuracy and reliability of CO assessment were also analyzed. Methods Paired CO measured by both thermodilution (TCO) and Doppler method (DCO) were obtained before incision, immediately after CPB, 15 minutes after CPB, 30 minutes after CPB, 45 minutes after CPB, and at the end of surgery. The DCO was converted from TEE measured DABF using theoretical proportion (70%) of DABF/CO. Regression analysis, Bland-Altman graph, and Polar plot were used to analyze the correlation and agreement between the CO measurements by the two methods. Parameters were compared by one-way ANOVA among different time points. Results A total of 132 pairs of CO measurements were obtained from 22 patients. The average proportion of DABF/TCO ranged from 54% before CPB to 63% after CBP. A good correlation between DCO and TCO (r = 0.81) was found. The Bland-Altman analysis showed a large positive bias between the TCO and DCO. The Polar plot also showed a poor concordance between changes of DCO and TCO. The proportion of DABF/TCO had a mild negative correlation with systemic vascular resistance index (SVRI) but not with cardiac output index (CI). Conclusions The CO, converted from TEE measured DABF, was underestimated in patients undergoing cardiac surgery. The varied proportion between DABF and CO mainly influenced the accuracy and reliability of CO assessment. Trial registration: Chinese Clinical Trials Register Identifier: ChiCTR-OCS-12002789 (retrospective registered). Date: 2012.12.21

Segmental Strain for Myocardial Scar Detection in Acute Infarcts and Follow-Up CMR Using Non-Contrast Cine Images

Aims Scar tissue from myocardial infarction is best visualized with cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE). Gadolinium-free alternatives for detection of myocardial scars are limited. This study investigated the feasibility of myocardial scar detection in acute infarcts and follow-up CMR using non-contrast cine images. Methods Fifty-seven patients with acute infarcts (15 female, mean age 61 ± 12 years, CMR 2.8 ± 2 days after infarction) were retrospectively evaluated with follow-up CMR exams available in thirty-two patients (9 female, 35 ± 14 days after infarction). Twenty-eight patients with normal CMR scans (2 female, mean age 47 ± 8 years) served as controls. Global and segmental strain parameters (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS], segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], and segmental peak radial strain [SPRS]) were calculated from standard non-contrast balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Visual assessment of wall motion abnormalities on short axis cine images, as well as segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) of every patient (acute imaging and follow-up CMR) and control were presented for two blinded readers in random order, who were advised to localize potentially infarcted segments, blinded to LGE images and clinical information.Results While global strain values were impaired in patients with acute infarcts compared to controls (GPCS p= 0.01; GPLS p= 0.04; GPRS p= 0.01), global strain was similar between first CMR and follow-up imaging in the subgroup of 32 patients (GPCS p= 0.7; GPLS p=0.8; GPRS p=0.2). In acute infarcts and in follow-up CMR, patients had reduced mean SPCS in infarcted segments compared to remote myocardium (acute p= 0.03, follow-up exams p= 0.02). SPCS values in infarcted areas were similar in acute infarcts and in follow-up exams (p=0.8). In acute infarcts 74.6% of all in LGE infarcted segments (141/189) were correctly localized in polar plot strain maps compared to 44.4% (84/189) of infarcted segments detected by visual wall motion assessment only (p < 0.01). In follow-up exams, 81.5% of all in LGE infarcted segments (93/114 segments) were correctly localized in polar plot strain maps compared to 51.8% (59/114) of infarcted segments detected by visual wall motion assessment (p < 0.01).Conclusion Segmental circumferential strain derived from routinely acquired cine sequences detects nearly 75% acute infarcts and about 80% of infarcts in follow-up CMR and can potentially be used for scar identification based on non-contrast cine images, when gadolinium cant not be applied or LGE images are not available.

Identification of Generalized Peptide Regions for Designing Vaccine Effective for All Significant Mutated Strains of SARS-CoV-2

Background: Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has become a worldwide pandemic and created an utmost crisis across the globe. To mitigate the crisis, the design of vaccines is a crucial solution. The frequent mutation of the virus demands generalized vaccine candidates, which would be effective for all mutated strains at present and for the strains that would evolve due to further new mutations in the virus. Objective: The objective of this study is to identify more frequently occurring mutated variants of SARS-CoV-2 and to suggest peptide vaccine candidates effective in common against the viral strains considered. Method: In this study, we have identified all currently prevailing mutated strains of SARS-CoV-2 through 2D Polar plot and Quotient Radius〖(q〗_R) characterization descriptor. Then, by considering the top eight mutation strains, which are significant due to their frequency of occurrence, peptide regions suitable for vaccine design have been identified with the help of a mathematical model – 2D Polygon Representation, followed by the evaluation of epitope potential and ensuring that there is no case of any autoimmune threat. Lastly, in order to verify whether this entire approach is applicable for vaccine design against any other virus in general, we have made a comparative study between the peptide vaccine candidates prescribed for the Zika virus using the current approach and a list of potential vaccine candidates for the same already established in the past. Results: We have finally suggested three generalized peptide regions which would be suitable as sustainable peptide vaccine candidates against SARS-CoV-2 irrespective of its currently prevailing strains as well any other variant of the same that may appear in the future. We also observed that during the comparative study using the case of E protein of Zika virus, the peptide regions suggested using the new approach matched with the already established results. Conclusion: The study, therefore, illustrates an approach that would help in developing peptide vaccine against SARS-CoV-2 by suggesting those peptide regions which can be targeted irrespective of any mutated form of this virus. The consistency with which this entire approach was also able to figure out similar vaccine candidates for Zika virus with utmost accuracy proves that this protocol can be extended for peptide vaccine design against any other virus in the future.

Dampak Pelaksanaan Pembatasan Sosial Berskala Besar (PSBB) Terhadap Konsentrasi PM10 di Pekanbaru

Dampak Pelaksanaan Pembatasan Sosial Berskala Besar (PSBB) Terhadap Konsentrasi PM10 di Pekanbaru. Salah satu faktor penurunan kualitas udara dapat disebabkan oleh aktivitas manusia. Penetapan Pembatasan Sosial Berskala Besar (PSBB) karena pandemi Covid-19 mengakibatkan penurunan aktivitas masyarakat diluar ruangan. Tujuan penelitian ini adalah membandingkan kondisi kualitas udara di Pekanbaru sebelum dan saat diterapkan PSBB. Data yang digunakan adalah data konsentrasi PM10 hasil pengukuran PM10 Analyzer, BAM1020. Statistik deskriptif dan uji Mann-Whitney U test sebagai uji non-parametrik untuk menentukan perubahan signifikansi dari PM10 sebelum dan saat PSSB. Hasil penelitian menunjukkan bahwa sebelum dan saat PSBB, konsentrasi PM10 di Pekanbaru berada dalam kategori baik (0-50 µg/m3). Berdasarkan distribusi frekuensi kondisi sebelum PSBB, konsentrasi PM10 lebih tinggi jika dibandingkan saat kondisi PSBB. Kemudian berdasarkan polar plot sebaran konsentrasi PM10 bervariasi dengan konsentrasi terbesar sebelum PSBB yaitu antara 12-14 µg/m3 pada arah Barat Laut, sedangkan untuk kondisi saat PSBB konsentrasi terbesar antara 9-10 µg/m3 pada arah Timur Laut. Berdasarkan rata-rata periode waktu per jam dan harian menunjukkan bahwa konsentrasi PM10 cenderung lebih tinggi saat malam hari dibandingkan siang hari dan konsentrasi PM10 tertinggi terjadi pada hari Selasa dan terendah pada hari Minggu. Hasil Uji Mann-Whitney menunjukkan ada perubahan yang signifikan dalam konsentrasi PM10 sebelum dan saat PSBB di Pekanbaru.

Technical note: Diagnostic efficiency – specific evaluation of model performance

A better understanding of the reasons why hydrological model performance is unsatisfying represents a crucial part of meaningful model evaluation. However, current evaluation efforts are mostly based on aggregated efficiency measures such as Kling–Gupta efficiency (KGE) or Nash–Sutcliffe efficiency (NSE). These aggregated measures provide a relative gradation of model performance. Especially in the case of a weak model performance it is important to identify the different errors which may have caused such unsatisfactory predictions. These errors may originate from the model parameters, the model structure, and/or the input data. In order to provide more insight, we define three types of errors which may be related to their source: constant error (e.g. caused by consistent input data error such as precipitation), dynamic error (e.g. structural model errors such as a deficient storage routine) and timing error (e.g. caused by input data errors or deficient model routines/parameters). Based on these types of errors, we propose the novel diagnostic efficiency (DE) measure, which accounts for these three error types. The disaggregation of DE into its three metric terms can be visualized in a plain radial space using diagnostic polar plots. A major advantage of this visualization technique is that error contributions can be clearly differentiated. In order to provide a proof of concept, we first generated time series artificially with the three different error types (i.e. simulations are surrogated by manipulating observations). By computing DE and the related diagnostic polar plots for the reproduced errors, we could then supply evidence for the concept. Finally, we tested the applicability of our approach for a modelling example. For a particular catchment, we compared streamflow simulations realized with different parameter sets to the observed streamflow. For this modelling example, the diagnostic polar plot suggests that dynamic errors explain the overall error to a large extent. The proposed evaluation approach provides a diagnostic tool for model developers and model users and the diagnostic polar plot facilitates interpretation of the proposed performance measure as well as a relative gradation of model performance similar to the well-established efficiency measures in hydrology.

Efficacy of echocardiography for differential diagnosis of left ventricular hypertrophy: special focus on speckle-tracking longitudinal strain

Left ventricular (LV) hypertrophy (LVH) is a frequent imaging finding in daily clinical practice, and its presence is associated with poor outcomes and ventricular arrhythmias. It is commonly detected in athletes, arterial hypertension, aortic stenosis, hypertrophic cardiomyopathy, cardiac amyloidosis, Fabry disease, or Friedreich’s ataxia. Echocardiography plays an important role in detecting LVH and underlying causes in current clinical practice. While echocardiography is essential for the quantification and early detection of LV structural findings for various cardiovascular diseases, it has been reported that speckle-tracking echocardiographic parameters are also useful for the detection of early LV structural abnormalities. In particular, global longitudinal strain (GLS) assessed by two-dimensional speckle-tracking echocardiography is reportedly a sensitive marker for early subtle abnormalities of LV myocardial performance, helpful for the prediction of outcomes for various cardiac diseases, and superior to conventional echocardiographic indices. GLS is determined as the averaged peak longitudinal strain of 18 LV segments from standard apical views and can be assessed as a polar plot. This polar plot longitudinal strain mapping offers an intuitive visual overview of the global and regional LV longitudinal myocardial function status of various cardiomyopathies with LVH. This mapping is clinically practicable and the plot patterns obtainable as the result of further development of this technique for clinical practice provide clues to the etiology of cardiomyopathies. This article reviews the efficacy of echocardiography for differential diagnosis of LVH, with a special focus on the utility of speckle-tracking longitudinal strain.