Characteristic Calibration Research Articles

Risk assessment using DEVI and CARPREG -1 score to predict maternal adverse cardiac cvents in pregnancies with valvular heart disease: external validation study from MPAC registry

Abstract Background Even though many risk assessment tools in pregnant women with valvular heart disease (VHD) are available, validation studies are few that assess their performance in diverse settings, which is needed prior to the application of routine clinical practice. Objectives To validate and establish the clinical utility of two risk stratification tools – DEVI (VHD-specific tool) and CARPREG-I in predicting adverse cardiac events in pregnant patients with VHD. Methods This cohort study involved consecutive pregnancies complicated with VHD enrolled in the prospective MPAC registry from July 2016 to December 2019(1). The ability to discriminate those with and without adverse cardiac outcomes was assessed using the area under the curve for both the DEVI and CARPREG-1 scores. Performance was assessed through discrimination and calibration characteristics. Clinical utility was evaluated with Decision Curve Analysis. Results Among 1029 pregnancies complicated with heart disease in the MPAC registry cohort, 604(52.3%) with valvular heart disease were included in this analysis. One or more composite adverse cardiac events occurred in 70 (11.6%) pregnancies during antenatal or the early postpartum period. Mitral regurgitation was the most common lesion (67.7%). In assessing the pregnancy outcomes, those who continued past 20 weeks were included, with the majority (92.0%) delivered at term, and the cesarean rates were 33.6% (n=203). The most common adverse event was heart failure (n=32, 5.3%), most of which (68.6%) occurred in the postnatal period. There were 11 maternal deaths (1.8%) during the study period, six among those with mechanical heart valves (four prosthetic valve thrombosis), two among those with severe mitral stenosis and pulmonary hypertension and two with severe mitral regurgitation and infective endocarditis. The area under the receiver operating characteristic curve (AUC) was 0.766, with 95% confidence intervals (CI) 0.703- 0.828 for DEVI and 0.703 (95%CI 0.644- 0.763) for CARPREG-I models. Calibration plots suggested that the DEVI score overestimates risk at higher probabilities, whereas the CARPREG-I score underestimates the risk at most probabilities. Decision curve analysis demonstrated that both models were useful across predicted probability thresholds between 10% and 60%. Conclusion In this external validation study in pregnant women with primary rheumatic VHD, DEVI and CARPREG-I scores showed good discrimination ability and clinical utility across various probabilities. Both can be used to classify those who develop adverse cardiac outcomes during pregnancy and childbirth. However, both models need recalibration to improve the agreement between the predicted and observed events prior to routine application in diverse clinical settings.Figure 1.a and b ROC and Decision Curves

Research trends and mapping knowledge for maxillary sinus augmentation in oral and maxillofacial surgery

BackgroundThe method most frequently employed to alleviate the deficiency of vertical bone volume in the maxillary posterior region is maxillary sinus augmentation. Given its importance in the field of dental implants and its possible impact on implant survival, it is crucial to assess the caliber and bibliometric characteristics of research related to maxillary sinus augmentation. This study aimed to understand the development and trends of studies and guide future studies by performing a bibliometric analysis of research related to maxillary sinus augmentation. MethodsThe Web of Science database was searched on 29.05.2024 with the developed search strategy. Articles were listed in descending order according to the number of citations and analyzed using the Bibliometrix program prepared in R base. The articles were analyzed in four sections: performance analysis, word analysis, collaboration analysis, and thematic analysis. ResultsWang HL is the most frequently listed author on this topic with 24 h-indexes and 1686 total citations. The highest number of articles were published in 2017, with 102 articles with an average of 2.7 citations. The most popular keyword was "dental implants." with 426 usages. Italy and the USA are the countries that have published the most collaborative papers. Clinical Oral Implants Research comes at the top when evaluating the journals that publish on maxillary sinus augmentation based on the h-index. Basic research and technical-oriented studies between 1999 and 2005 have given way to more clinical and patient-oriented research. ConclusionThis bibliometric study will serve as a guide for future research by illustrating the existing state of knowledge and limitations regarding the development of sinus lifting methods, given the constantly growing demand for implant therapy.

Density of soil composite composition in a changing magnetic field

The advancement of technical means for determining soil density in precision (controlled) agriculture necessitates the enhancement of non-destructive flow interaction methods. There is also a need to improve methods for assessing soil density, as existing deviations from optimal values adversely affect the yield of agricultural crops. This research aims to establish the density of the composites in the granulometric composition of soil by determining the self-induction voltage in a changing magnetic field. The research methods are adapted to determine the relationships of Larmor precession under variable inductive current for the density of each composite in the granulometric soil composition. Experimental investigations were conducted by measuring the self-induction voltage of a solenoid acting as a sensor for each of the composites located within the core. The processing of experimental results was carried out according to the principles of mathematical statistics and probability theory, using approximations in the Excel and Statistica software packages. Based on the results of the experimental investigations, models of the relationships between the density ρ (1.0-1.5 g/cm3) of soil composites and the self-induction voltage eL=184-192 mV, with a generator voltage of 5 V and determination coefficients R2=0.95-0.99, have been established. These models enable the assessment of soil density with high accuracy, thereby facilitating the optimisation of agronomic processes. It has been determined that these models can be used with a high degree of reliability as calibration characteristics for the design of technical means for flow-based non-destructive measurement of the density of the main soil types in Ukraine. Furthermore, it has been identified that future research should focus on a more in-depth investigation of the relationships between magnetic permeability and the agrophysical characteristics of soil within the locally defined inductive field of the sensor (solenoid). An applied aspect of the obtained results is the further development of adaptive machinery and monitoring systems for soil conditions, aimed at achieving optimal cultivation indicators, as well as their utilisation by research institutions and instrument-making enterprises

Advantages of Inter‐Calibration for Geostationary Satellite Sensors Onboard Twin Satellites

AbstractTo address the increasing demand for diurnal information on trace gases and aerosols, a series of geostationary (GEO) satellite programs called GEO‐constellation have been initiated, with the launch of the Geostationary Environment Monitoring Spectrometer (GEMS) onboard Geostationary Korea Multi‐Purpose Satellite 2B (GK2B). To assess the sensor performance of GEMS in orbit, the current work suggests employing an inter‐calibration methodology involving the Advanced Meteorological Imager (AMI) aboard its twin satellite, GK2A. Twin satellites have a significant advantage in obtaining collocation data sets across diverse spatiotemporal, angular, and atmospheric conditions, enabling rigorous collocation criteria effectively reducing mismatch uncertainty. The results present robust correlation coefficients over 0.99, revealing the current calibration characteristics of the sensors. This research emphasizes the advantages of the GEO‐GEO inter‐calibration, particularly the capability of analyzing spatial and temporal dependencies. These findings confirm the mutual benefit of utilizing the sensors in similar configurations, highlighting their importance for future satellite monitoring endeavors.

Assessment of the Performance of the Dose Calibrator Used in Radioactivity Measurement

Aims: This study aimed to evaluate the principal technical characteristics of a well-type gas-filled ionization chamber dose calibrator used in measuring radiopharmaceutical activity, namely accuracy, repeatability, and linearity. Furthermore, this work also explored the correlation between the device’s response and the position and volume of the radiopharmaceutical I-131. Materials and Methods: Experimental measurements were conducted on the ATOMLAB 500 dose calibrator using NIST traceable Cs-137 source to determine the accuracy and repeatability. For the linearity test, the Tc-99m solution produced at the Dalat Nuclear Research Institute, Vietnam was utilized to examine the performance of the device over a wide measurement range. Effects resulting from different volumes and measuring positions were also determined by experiments and Monte Carlo simulations. Results: Based on acceptance test results, it is revealed that the dose calibrator’s characteristics comply with international standards, where the deviations of accuracy, repeatability, and linearity are all lower than 1.0%. The response of the dose calibrator to different measuring positions and volumes was well controlled. To rectify the discrepancy in the response to the changes in solution volume, correction functions were proposed. Conclusions: It is concluded that the dose calibrator is suitable for radioactivity quantification and adheres to standards recommended by international organizations for nuclear medicine activities. The outcome of this work will serve as the foundation for establishing a standard for I-131 radiopharmaceuticals’ radioactivity in Vietnam.

Stability analysis of layered circular rock tunnels considering anchor reinforcement based on an enhanced mesh-free method

The impact of geotechnical structure and support construction on the stability of a layered circular rock tunnel was investigated based on an improved mesh-free method. The Smoothed Particle Hydrodynamics (SPH) was improved by incorporating a total bridge broken strategy into the kernel function and was validated through analysis of the mechanical behavior in circular opening problem and uniaxial compression tests. The Particle Domain Search (PDS) method is utilized to create crack pathways and implement anchor reinforcement in specific areas without the requirement for grid division. An SPH model of the Muzhailing tunnel was established to investigate the stability of the surrounding rock considering different anchor lengths and spacing. The result indicated that the enhanced SPH method provides a feasible approach for the rapid assessment of tunnel convergence displacement and damage coefficients. Furthermore, this method was validated through laboratory experiments and analytical solutions. For layered tunnels with other different dip angles, this approach offers a general optimization strategy for anchor reinforcing surrounding rock. These findings suggest that the enhanced mesh-free method, owing to its characteristics of efficient parameter calibration and computation, can be further expanded to the rapid assessment of the stability of layered slopes and foundations considering anchor reinforcement.

Planar and volumetric imaging dosimetry for longitudinal projection extended cone beam CT based adaptive radiotherapy

BackgroundThe objective of this study is to provide a detailed insight into the broad beam dosimetric characteristics of two commercial cone beam computed tomography (CBCT) imaging systems to complement the longitudinal projection extended CBCT based image guided adaptive radiotherapy (IGART). Methods and materialsThe absolute dose calibration, planar and volumetric dosimetric characteristics of two CBCT imaging systems viz., the Clinac 2100 C/D On-Board Imager (OBI) and the TrueBeam X-ray Imaging system (XI) (Varian Medical Systems, Palo Alto, CA) were investigated. Reference dosimetry specific to volumetric CBCT imaging mode was performed as per American Association of Physicists in Medicine (AAPM) task group (TG) 61 protocol using calibrated 0.6 cc Farmer ionization chamber (30010, PTW Dosimetry Company, Germany). The rotational planar and volumetric dosimetry was performed after calibrating the OCTAVIUS 1500 detector array as a mere photon detector, with and without the detachable hemisphere of 4D Modular phantom. ResultsThe absolute dose of half-fan XI CBCT was found to be 1.2 times lower when compared to OBI CBCT. The abutting kV cone beam dosimetry specific to dual-scan CBCT fusion technique showed a wider in-plane profile for the OBI system when compared to the XI system, due to an additional field opening of 3.4 cm used for half-fan mode in the former. The reconstructed volumetric imaging dose distribution specific to half-fan geometry and dynamic movement of gantry, brought to light valuable details about the kV dose distribution. ConclusionThe planar and 3D imaging dosimetry reported in this study paves the way for the integration of volumetric imaging dose reconstruction capabilities during high precision radiotherapy to demonstrate a complete picture of the total dose delivered to the patient during the planned course of IGART.

External validation of the computer aided risk scoring system in predicting in-hospital mortality following emergency medical admissions

BackgroundClinical prediction models have the potential to improve the quality of care and enhance patient safety outcomes. A Computer-aided Risk Scoring system (CARSS) was previously developed to predict in-hospital mortality following emergency admissions based on routinely collected blood tests and vitals. We aimed to externally validate the CARSS model. MethodsIn this retrospective external validation study, we considered all adult (≥18 years) emergency medical admissions discharged between 11/11/2020 and 11/11/2022 from The Rotherham Foundation Trust (TRFT), UK. We assessed the predictive performance of the CARSS model based on its discriminative (c-statistic) and calibration characteristics (calibration slope and calibration plots). ResultsOut of 32,774 admissions, 20,422 (62.3 %) admissions were included. The TRFT sample had similar demographic characteristics to the development sample but had higher mortality (6.1 % versus 5.7 %). The CARSS model demonstrated good discrimination (c-statistic 0.87 [95 % CI 0.86–0.88]) and good calibration to the TRFT dataset (slope = 1.03 [95 % CI 0.98–1.08] intercept = 0 [95 % CI −0.06–0.07]) after re-calibrating for differences in baseline mortality (intercept = 0.96 [95 % CI 0.90–1.03] before re-calibration). ConclusionIn summary, the CARSS model is externally validated after correcting the baseline risk of death between development and validation datasets. External validation of the CARSS model showed that it under-predicted in-hospital mortality. Re-calibration of this model showed adequate performance in the TRFT dataset.

Development of the Universal Air Collector Design for Measuring the Flow Rate of Swirling Air Flow Using an Integral Thermoanemometer

Measurement of the swirling air flow rate and average speed of air at air distribution units of ventilation systems is a rather difficult task due to the fact that the air flow enters the measuring device at different angles. As a result, significant measurement errors can occur when using point thermoanemometers or other flow meters. The use of integral anemometers facilitates the measurement process. However, it is necessary to eliminate the errors associated with changes in the angle of the air flow to the sensing element of the measuring device. To do this, it is necessary to ensure a rectilinear structure of the air flow using a transitional air collector and rectifier. The aim of this paper is to develop a design of an air collector device that will allow to measure the flow rate of a swirling air flow. The objectives of the paper are to optimize the geometrical parameters of the air collector to ensure a rectilinear flow, minimize its dimensions and aerodynamic drag. The correctness of the air collector design was evaluated by matching the calibration characteristic of the probe of an integral thermoanemometer in the presence of a vortex diffuser in front of the air collector and in its absence. The proposed device has a rectangular shape and consists of a receiver, a rectifying grid, a chamber, an accelerating and stabilizing section, at the outlet of which a thermoanemometer probe is installed. The receiver and the accelerating section are tapered along their length, while the chamber and the stabilizing section have a constant cross-section. The rectifying grid is installed inside the chamber and has a square-shaped honeycomb structure. Several options of the air collector design with different geometrical parameters were studied using computer modelling. The dependence of aerodynamic drag on air flow was plotted. The optimal design of the air collector was chosen, for which a life-size physical model was created. The calibration characteristics of the measuring probe with an air collector were experimentally obtained when a swirling air flow was applied. The developed universal air collector allows the air flow rate measurement at the outlets of almost any air distribution devices of ventilation systems of buildings.

Computed tomography-based nomogram of Siewert type II/III adenocarcinoma of esophagogastric junction to predict response to docetaxel, oxaliplatin and S-1.

Neoadjuvant chemotherapy (NAC) has become the standard care for advanced adenocarcinoma of esophagogastric junction (AEG), although a part of the patients cannot benefit from NAC. There are no models based on baseline computed tomography (CT) to predict response of Siewert type II or III AEG to NAC with docetaxel, oxaliplatin and S-1 (DOS). To develop a CT-based nomogram to predict response of Siewert type II/III AEG to NAC with DOS. One hundred and twenty-eight consecutive patients with confirmed Siewert type II/III AEG underwent CT before and after three cycles of NAC with DOS, and were randomly and consecutively assigned to the training cohort (TC) (n = 94) and the validation cohort (VC) (n = 34). Therapeutic effect was assessed by disease-control rate and progressive disease according to the Response Evaluation Criteria in Solid Tumors (version 1.1) criteria. Possible prognostic factors associated with responses after DOS treatment including Siewert classification, gross tumor volume (GTV), and cT and cN stages were evaluated using pretherapeutic CT data in addition to sex and age. Univariate and multivariate analyses of CT and clinical features in the TC were performed to determine independent factors associated with response to DOS. A nomogram was established based on independent factors to predict the response. The predictive performance of the nomogram was evaluated by Concordance index (C-index), calibration and receiver operating characteristics curve in the TC and VC. Univariate analysis showed that Siewert type (52/55 vs 29/39, P = 0.005), pretherapeutic cT stage (57/62 vs 24/32, P = 0.028), GTV (47.3 ± 27.4 vs 73.2 ± 54.3, P = 0.040) were significantly associated with response to DOS in the TC. Multivariate analysis of the TC also showed that the pretherapeutic cT stage, GTV and Siewert type were independent predictive factors related to response to DOS (odds ratio = 4.631, 1.027 and 7.639, respectively; all P < 0.05). The nomogram developed with these independent factors showed an excellent performance to predict response to DOS in the TC and VC (C-index: 0.838 and 0.824), with area under the receiver operating characteristic curve of 0.838 and 0.824, respectively. The calibration curves showed that the practical and predicted response to DOS effectively coincided. A novel nomogram developed with pretherapeutic cT stage, GTV and Siewert type predicted the response of Siewert type II/III AEG to NAC with DOS.

THE METHOD OF MONITORING THE PARAMETERS OF TRANSFORMER OIL DURING ITS REGENERATION

The dependences of the luminescence flux on the parameters of the GK transformer oil during its regeneration are investigated and a technique for its photoluminescent control is developed. In the process of regeneration, the radiating properties improve – the photoluminescence flux increases. Statistically reliable dependences of the photoluminescence flux on the oil parameters (acid number, breakdown voltage, moisture content and the tangent of the dielectric loss angle) were obtained. For the practical implementation of the photoluminescent control technique of transformer oil, it is advisable to use exciting radiation with a wavelength of 396 nm and flow registration in the range of 412…600 nm. The technique includes sample preparation, excitation and registration of luminescence, signal amplification and determination of the required parameter based on calibration characteristics. The proposed technique can be used to control the quality of oil during its regeneration, as well as during the operation of oil in high-voltage equipment.

Calculation of dielectric constant calibration characteristics of sensors using the method of moments

This research is devoted to the issues of further development of methods of experimental measurement of dielectric characteristics of solid materials, liquids and liquid–gas media, which are foam structures. In recent decades, foam structures have gradually filled and supplanted traditional dielectric materials. There are still no scientific and metrology-based methods and devices for correct measurements of foam. In the paper, the method of moments (MoM) is employed for resonator measurements. The obtained results for a wide range of dielectric constants from 1 to 80 are interesting for determining the sensitivity of measurements, the influence of frequency measurement errors, and determining the number of measurement points.

A Novel Risk Score to Predict Thirty-Day Readmissions after Acute Type A Aortic Dissections

Background: Readmissions following acute type A aortic dissections (ATAAD) are associated with potentially worse clinical outcomes and increased hospital costs. Predicting which patients are at risk for readmission may guide patient management prior to discharge. Methods: The National Readmissions Database was utilized to identify patients treated for ATAAD between 2010 and 2018. Univariate mixed effects logistic regression was used to assess each variable. Variables were assigned risk points based off the bootstrapped (bias-corrected) odds ratio of the final variable model according to the Johnson's scoring system. A mixed effect logistic regression was run on the risk score (sum of risk points) and 30-day readmission. Calibration plots and predicted readmission curves were generated for model assessment. Results: A total of 30,727 type A aortic dissections were identified. The majority of ATAAD (66%) were in men with a median age of 61 years and 30-day readmission rate of 19.4%. The risk scores ranging from –1 to 14 mapped to readmission probabilities between 3.5% and 29% for ATAAD. The predictive model showed good calibration and receiver operator characteristics with an area under the curve (AUC) of 0.81. Being a resident of the hospital state (OR: 2.01 [1.64, 2.47], p &lt; 0.001) was the highest contributor to readmissions followed by chronic kidney disease (1.35 [1.16, 1.56], p = 0), discharge to a short-term facility (1.31 [1.09, 1.57], p = 0.003), and developing a myocardial infarction (1.20 [1.00, 1.45], p = 0.048). Conclusions: The readmission model had good predictive capability given by the large AUC. Being a resident in the State of the index admission was the most significant contributor to readmission.

ANALYSIS OF THE METHODICAL APPARATUS FOR FORECASTING THE QUALITY CHARACTERISTICS OF ARTILLERY GUNS AND AMMUNITION

This scientific article is aimed at the analysis of the methodological apparatus used to predict the qualitative characteristics of artillery guns and ammunition. Artillery plays a key role in military operations, and it is important to understand and predict the key parameters that determine its effectiveness and safety. This work examines in detail the methodical apparatus for forecasting the qualitative characteristics of artillery guns and ammunition. One of the main ways to increase the balance of the process of development of artillery weapons samples is program planning, which, based on the results of forecasted development studies, determines the main directions of research on the development of weapons. The second path concerns the technical characteristics of artillery guns, including their caliber, firing range, accuracy and charge characteristics. It is important to determine how these parameters affect the gun’s ability to engage and to determine their relevance to the needs of military operations The third path focuses on the cost of artillery systems. The cost of development, production, maintenance and modernization of the systems is projected, as well as the economic aspects and the impact on the budget are considered. This article aims to make a significant contribution to the development of scientific approaches to predicting the quality characteristics of artillery guns and ammunition. The results of the research can be useful for the military, defense and industrial sectors aimed at ensuring national security and military activities. Keywords: artillery guns, ammunition, specifications, quality characteristics, cost, safety, forecasting, analysis, military operations, national security, explosive charges, firing range, technology, modernization, production, maintenance, technical system.

External Validation of Models for Predicting Disability in Community-Dwelling Older People in the Netherlands: A Comparative Study.

Advanced statistical modeling techniques may help predict health outcomes. However, it is not the case that these modeling techniques always outperform traditional techniques such as regression techniques. In this study, external validation was carried out for five modeling strategies for the prediction of the disability of community-dwelling older people in the Netherlands. We analyzed data from five studies consisting of community-dwelling older people in the Netherlands. For the prediction of the total disability score as measured with the Groningen Activity Restriction Scale (GARS), we used fourteen predictors as measured with the Tilburg Frailty Indicator (TFI). Both the TFI and the GARS are self-report questionnaires. For the modeling, five statistical modeling techniques were evaluated: general linear model (GLM), support vector machine (SVM), neural net (NN), recursive partitioning (RP), and random forest (RF). Each model was developed on one of the five data sets and then applied to each of the four remaining data sets. We assessed the performance of the models with calibration characteristics, the correlation coefficient, and the root of the mean squared error. The models GLM, SVM, RP, and RF showed satisfactory performance characteristics when validated on the validation data sets. All models showed poor performance characteristics for the deviating data set both for development and validation due to the deviating baseline characteristics compared to those of the other data sets. The performance of four models (GLM, SVM, RP, RF) on the development data sets was satisfactory. This was also the case for the validation data sets, except when these models were developed on the deviating data set. The NN models showed a much worse performance on the validation data sets than on the development data sets.

A Modified Robust Nomogram for Predicting the Probability of Pelvic Lymph Node Invasion in Localized Prostate Cancer.

Improved predictive models for the risk of pelvic lymph node invasion (LNI) in localized prostate cancer (PCa) is important in decision making of pelvic lymph node dissection (PLND) or whole pelvic RT (WPRT). We aimed to establish a nomogram with improved robustness (Ruijin model) based on pre-treatment information. Continuous localized PCa patients with detailed prostate tumor biopsy information, treated with laparoscopic radical prostatectomy and PLND between 2013 and 2022 in single institution were retrospectively reviewed. A multivariable logistic regression model was fitted and represented the basis for a coefficient-based nomogram of predicting LNI. Comparisons between the Ruijin model and the Roach formula were conducted using the receiver operating characteristic-derived area under the curve (AUC), calibration plot, and decision-curve analyses (DCAs). In total, 624 patients with median age (69.5 year) were included in this analysis. The median number of pelvis lymph nodes removed was 6 (range: 2-30). LNI was found in 35 (5.6%) patients. In the multivariable logistic regression model, total prostate-specific antigen (OR = 1.008, P = 0.025), percentage of cores with the highest-grade PCa (OR = 14.822, P<0.001), clinical stage (III vs. I-II: OR = 7.733, P = 0.008), and biopsy Gleason Grading Group (G3 vs G1-2: OR = 3.152, P = 0.082; G4 vs G1-2: OR = 3.065, P = 0.083; G5 vs G1-2: OR = 5.262, P = 0.008;) were included and formed the basis for the nomogram. The predictive accuracy of Ruijin nomogram in our cohort was 87.7%. Using a cutoff of 4% based on Ruijin nomogram, 395 (63%) PLND would be spared and LNI would be missed in only two (0.5%) patients. The sensitivity, specificity, and negative predictive value associated with the 4% cutoff were 94.3%, 66.7%, and 99.5%, respectively. As compared with the Roach formula, the Ruijin model showed higher AUC (87.7% vs 80.9%, Z = -2.013, P = 0.044), better calibration characteristics, and a higher net benefit at DCA. We developed a novel nomogram for predicting the LNI in localized PCa patients with detailed biopsy information. PLND or WPRT could be avoided in patients with a risk of LNI <4%, so as to spare more than 60% of unnecessary pelvic nodal treatment with a cost of missing only 0.5% LNIs.

Validation of Risk Stratification for Cardiac Events in Pregnant Women With Valvular Heart Disease

BackgroundMost risk stratification tools for pregnant patients with heart disease were developed in high-income countries and in populations with predominantly congenital heart disease, and therefore, may not be generalizable to those with valvular heart disease (VHD). ObjectivesThe purpose of this study was to validate and establish the clinical utility of 2 risk stratification tools—DEVI (VHD-specific tool) and CARPREG-II—for predicting adverse cardiac events in pregnant patients with VHD. MethodsWe conducted a cohort study involving consecutive pregnancies complicated with VHD admitted to a tertiary center in a middle-income setting from January 2019 to April 2022. Individual risk for adverse composite cardiac events was calculated using DEVI and CARPREG-II models. Performance was assessed through discrimination and calibration characteristics. Clinical utility was evaluated with Decision Curve Analysis. ResultsOf 577 eligible pregnancies, 69 (12.1%) experienced a component of the composite outcome. A majority (94.7%) had rheumatic etiology, with mitral regurgitation as the predominant lesion (48.2%). The area under the receiver-operating characteristic curve was 0.884 (95% CI: 0.844-0.923) for the DEVI and 0.808 (95% CI: 0.753-0.863) for the CARPREG-II models. Calibration plots suggested that DEVI score overestimates risk at higher probabilities, whereas CARPREG-II score overestimates risk at both extremes and underestimates risk at middle probabilities. Decision curve analysis demonstrated that both models were useful across predicted probability thresholds between 10% and 50%. ConclusionsIn pregnant patients with VHD, DEVI and CARPREG-II scores showed good discriminative ability and clinical utility across a range of probabilities. The DEVI score showed better agreement between predicted probabilities and observed events.

Использование смартфона в твердофазно-флуориметрическом определении некоторых полипептидных антибиотиков в лекарственных препаратах

The analysis of semi-products at different stages of production and finished medicinal products is an integral part of an effective quality assurance system for pharmaceutical production. The traditional methods used in the pharmaceutical field, such as capillary electrophoresis, gas and liquid chromatography, are quite versatile and effective. However, they are distinguished by the high cost of instrumentation and component materials, the need to use high-purity solvents, the lack of mobility and the possibility of in situ studies. Such shortcomings can be overcome by using the digital colorimetry method. Its significant popularization has been facilitated by the development of portable and personal electronic devices, among which the smartphone can be distinguished. The aim of the work was to develop a fast and simple method for the determination of a number of polypeptide antibiotics in drugs by digital colorimetry using a smartphone as a color recording device. To implement the solid phase fluorimetric determination of polypeptide antibiotics, HPTLC plates based on silica gel with an aluminum substrate were used as a matrix. Under these conditions, the fluorescence of actinomycin D, virginiamycin M1, virginiamycin S1, and novobiocin was observed when exposed to monochromatic radiation in the UV part of the spectrum (365 nm). The measurement of fluorescence intensity on the surface of the matrices was carried out using a smartphone. Calibration characteristics were constructed for the determination of polypeptide antibiotics in the concentration range of 32–500 μg/mL. The method for assessing the quality of finished drugs was tested on commercial products “Piostacin”, “Cosmegen”, “Dactinomycin” purchased in retail chains. The relative standard deviation of the analysis results does not exceed 0.05. The duration of the analysis was 10–15 min. Based on the results of the studies, the paper presents a method for determining some antibiotics of the polypeptide series by the intrinsic fluorescence of deposited solutions on a solid substrate during treatment with monochromatic UV radiation. The experimental delivery conditions used allow the analysis of drugs based on actinomycin D, virginiamycin M1, virginiamycin S1, and novobiocin.

A Voltammetric Sensor Based on Aluminophosphate Zeolite and a Composite of Betulinic Acid with a Chitosan Polyelectrolyte Complex for the Identification and Determination of Naproxen Enantiomers

A voltammetric sensor was developed based on a glassy carbon electrode with aluminophosphate zeolite finely dispersed on its surface, modified with a polyelectrolyte complex of chitosan with succinyl chitosan and betulinic acid, for the selective detection and determination of naproxen enantiomers. The electrochemical and analytical characteristics of the sensor were studied, and the effective electrode surface area (A = 9.8 ± 0.5 mm2) and charge transfer resistance (Ret = 649.9 ± 0.4 Ω) were calculated. In determining naproxen enantiomers, calibration characteristics are linear in the range from 2.5 × 10–5 to 1 × 10–3 M with limits of detection of 1.1 × 10–7 and 1.5 × 10–7 M and limits of quantification of 3.6 × 10–7 and 4.9 × 10–7 M for R- and S-naproxen, respectively. The sensor is more sensitive to R-naproxen (∆Ep = 60 mV, ipR/ipS = 1.40). The proposed sensor was used to recognize and determine naproxen enantiomers in human urine and plasma samples. Statistical evaluation of the results by the standard addition method showed that there was no systematic error.

Spontaneous obliteration of a spinal perimedullary fistula.

We herewith report a young patient who had an incidental spinal vascular malformation of the cervicomedullary junction discovered during a work-up for anosmia. Angiography demonstrated a perimedullary spinal arteriovenous fistula with supply from lateral spinal arteries arising from bilateral V3 level segmental arteries. It was decided to manage the patient conservatively with magnetic resonance imaging monitored biannually. On a recent follow-up magnetic resonance, nearly 10 years later, we noted a subtle change in caliber and imaging characteristics at the posterior margin of the cervical medullary junction. Repeat digital-subtraction angiography showed no evidence of early venous filling from the previously involved branches. Microcatheter exploration of the right lateral spinal artery confirmed spontaneous occlusion of the spinal perimedullary arteriovenous fistula, without any persistent shunting. Spontaneous resolution of a spinal vascular malformation is rare; this case demonstrates the dynamic nature of shunting vascular malformations and that spontaneous obliteration of arteriovenous shunts is possible.