Stand-alone Test Research Articles

Development of a Persistent Current Mode 9.39 T (400 MHz) LTS/Bi-2223 NMR Magnet With a Bi-2223 Superconducting Joint

We developed and operated a persistent current (PC) mode 9.39 T (400 MHz for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sup> H NMR) LTS/Bi-2223 NMR magnet using a Bi-2223 insert coil with a superconducting joint. Firstly, we developed a basic joining procedure to achieve the superconducting joint for the high-strength Bi-2223 tape used for the insert coil. We applied this procedure to the coil. Secondly, a stand-alone PC mode operation test for the coil at 4.2 K was performed. No apparent field decay was observed owing to the superconducting joint. Finally, we installed the coil inside the LTS outer coil's bore to form a PC mode LTS/Bi-2223 NMR magnet system. We successfully demonstrated a 9.39 T PC mode operation of the magnet though the current of the insert coil was limited to 5 A. The field drift rate was as low as 0.4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3</sup> ppm h <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> . The joint resistance was estimated to be < 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−12</sup> Ω at 4.2 K and 0.26 T. To our best knowledge, this is the first demonstration of a Bi-2223 superconducting joint that realized a PC mode LTS/Bi-2223 NMR magnet. This is an important step towards full-scale PC mode Bi-2223 magnets, including a 30.5 T (1.3 GHz) LTS/HTS NMR magnet.

Diagnostic efficacy of ECG-derived ventricular gradient for the detection of chronic thromboembolic pulmonary hypertension in patients with acute pulmonary embolism

IntroductionApplication of the chronic thromboembolic pulmonary hypertension (CTEPH) rule out criteria (manual electrocardiogram [ECG] reading and N-terminal pro-brain natriuretic peptide [NTproBNP] test) can rule out CTEPH in pulmonary embolism (PE) patients with persistent dyspnea (InShape II algorithm). Increased pulmonary pressure may also be identified using automated ECG-derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO). MethodA predefined analysis of the InShape II study was performed. The diagnostic performance of the VG-RVPO for the detection of CTEPH and the incremental diagnostic value of the VG-RVPO as new rule-out criteria in the InShape II algorithm were evaluated. Results60 patients were included; 5 (8.3%) were ultimately diagnosed with CTEPH. The mean baseline VG-RVPO (at time of PE diagnosis) was −18.12 mV·ms for CTEPH patients and − 21.57 mV·ms for non-CTEPH patients (mean difference 3.46 mV·ms [95%CI −29.03 to 35.94]). The VG-RVPO (after 3–6 months follow-up) normalized in patients with and without CTEPH, without a clear between-group difference (mean Δ VG-RVPO of −8.68 and − 8.42 mV·ms respectively; mean difference of −0.25 mV·ms, [95%CI −12.94 to 12.44]). The overall predictive accuracy of baseline VG-RVPO, follow-up RVPO and Δ VG-RVPO for CTEPH was moderate to poor (ROC AUC 0.611, 0.514 and 0.539, respectively). Up to 76% of the required echocardiograms could have been avoided with VG-RVPO criteria replacing the InShape II rule-out criteria, however at cost of missing up to 80% of the CTEPH diagnoses. ConclusionWe could not demonstrate (additional) diagnostic value of VG-RVPO as standalone test or as on top of the InShape II algorithm.

Buriti Fabric Reinforced Epoxy Composites as a Novel Ballistic Component of a Multilayered Armor System

Buriti Fibers extracted from the leafstalk of palm tree, Mauritia flexuosa, native to the Amazon region, have been investigated as a reinforcement of polymer matrix composites. Recently, the fabric made from buriti fibers was also studied as a possible reinforcement of epoxy composites. In particular, the preliminary results of a 10 vol% buriti fabric epoxy composite in a multilayered armor system (MAS) displayed a satisfactory backface signature (BFS) but the composite target was not able to preserve its integrity after the ballistic impact. This motivated the present work, in which we carry out a complete statistical investigation of the ballistic performance of 10, 20, and 30 vol% buriti fabric epoxy composites as a MAS second layer against 7.62 mm rifle ammunition. BFS, associated with the depth of penetration in a clay witness simulating a human body, disclosed values of 18.9 to 25 mm, statistically similar and well below the lethal value of 44 mm specified by the international standard. Absorbed energy in stand-alone ballistic tests of 163–190 J for armor perforation were also found to be statistically higher than 58 ± 29 J obtained for the conventionally applied synthetic aramid fabric. The 30 vol% buriti fabric composites maintained the integrity of the MAS second layer, as required for use in body armor. Failure mechanisms found for the 10 vol% and 20 vol% buriti fabric composites by macro analysis and scanning electron microscopy confirmed the importance of a higher amount such as 30 vol% in order to achieve effective ballistic protection.

A-231 Can Embedded Performance Validity Measures Predict Performance on a Stand-Alone Test?

Abstract Objective: Determine the extent to which a group of embedded performance validity tests (PVT) predict performance on a stand-alone test; and examine the classification accuracy of embedded PVTs. Method: Participants were 102 adult patients who underwent neuropsychological evaluation (M age = 31.85, SD = 11.79; M education = 13.82, SD = 2.50; M FSIQ = 104.72). Patients were administered the Medical Symptom Validity Test (MSVT), and 10 embedded PVT scores were extracted from their neuropsychological profiles. Logistic regression determined the extent to which scores on embedded PVTs predicted MSVT designation as credible or noncredible. Classification accuracy also was calculated for the embedded PVTs, both individually and based on number of “failures.” Results: A final regression model (Chi-square (6) = 20.06, p = .003, Nagelkerke R Square = .42) was 38% sensitive, 97% specific, and correctly predicted credible patients (negative predictive accuracy = 95%) more often than noncredible patients (positive predictive accuracy = 50%). Several embedded PVTs had comparable classification accuracy. Conservatively defining noncredible performance as failure on at least three embedded PVTs produced the best combination of sensitivity (50%) and specificity (86%), and was associated with a false positive rate of 14%. Conclusions: Embedded PVTs correctly predict credible and noncredible performance on the MSVT at a high level. Although a multivariate predictive approach may have slightly more utility than examining embedded PVT scores separately, several individual PVTs have comparable accuracy. It remains unclear which approach is superior, and more research is needed.

To adjust or not to adjust: Cut-off scores in performance validity testing in Portuguese older adults with dementia.

The rising demographic of older adults worldwide has led to an increase in dementia cases. In order to ensure the proper allocation of care and resources to this clinical group, it is necessary to correctly distinguish between simulated versus bona-fide cognitive deficits typical of dementia. Performance Validity Tests (PVTs) are specifically designed to assess a lack of effort and the possible simulation of cognitive impairment. Previous research demonstrates that PVTs may be sensitive to dementia, thus inaccurately classifying real memory impairment as simulation. Here, we analyzed the sensitivity of PVTs in discriminating between dementia and simulation using receiver operating characteristic (ROC) curve analyses. Further, we examined the potential need for adjusting cut-off scores for three stand-alone (Test of Memory Malingering, Rey-15 Item Memory Test, and Coin in Hand-Extended Version) and one embedded (Reliable Digit Span) PVT for Portuguese older adults with dementia. The results showed that (1) all measures, except for the Coin in Hand— Extended version (CIH-EV), were sensitive to one or more sociodemographic and/or cognitive variables, and (2) it was necessary to adjust cut-off points for all measures. Additionally, the Rey-15 Item Memory Test did not demonstrate sufficient discriminating capacity for dementia. These results present important implications for clinical practice and the daily life of patients, as the use of incorrect cut-off points could impede patients from getting the resources they need.

A systematic review of economic evaluations of cervical cancer screening methods

ObjectiveThe aims of this systematic review were to (1) identify primary- and model-based economic evaluations of cervical cancer screening methods and to (2) provide a contextual summary of valuation outcomes associated with three types of cervical cancer screening tests: visual inspection with acetic acid, human papillomavirus deoxyribonucleic acid, and Papanicolaou smear.IntroductionCervical cancer screening is an important public health priority with the potential to improve the detection of precancerous lesions in high-risk females for early intervention and disease prevention. Test performance and cost-effectiveness differ based on the specific screening method used across different platforms. There is a need to appraise existing economic evaluations of cervical cancer screening methods.MethodsThis review considered primary-based and model-based full economic evaluations of cervical cancer screening methods. The evaluation methods of interest included cost-effectiveness analysis, cost-utility analysis, cost-minimization analysis, cost–benefit analysis, and cost-consequence analysis. We searched Scopus, PubMed, National Health Economic Evaluation Database (NH EED), Cochrane, and the Health Economic Evaluation Database for full economic evaluations of cancer screening methods. No formal date restrictions were applied. Model-based and primary-based full economic evaluations were included. A critical appraisal of included studies was performed by the main investigator, while a second independent reviewer assessed critical appraisal findings for any inconsistencies. Data were extracted using a standardised data extraction tool for economic evaluations. The ultimate outcomes of costs, effectiveness, benefits, and utilities of cervical cancer screening modalities were extracted from included studies, analysed, and summarised.ResultsFrom a total of 671 screened studies, 44 studies met the study inclusion criteria. Forty-three studies were cost-effectiveness analyses, one study reported both cost-utility and cost-effectiveness outcomes, and another study reported cost utilities of cervical cancer screening methods only. Human papillomavirus (HPV) DNA testing was reported as a dominant stand-alone screening test by 14 studies, while five studies reported visual inspection with acetic acid (VIA) as a dominant stand-alone screening test. Primary HPV screening strategies were dominant in 21 studies, while three studies reported cytology-based screening strategies as the dominant screening method.ConclusionsExisting evidence indicates that HPV-based and VIA testing strategies are cost-effective, but this is dependent on setting. Our review suggests the limited cost-effectiveness of cytology-based testing, which may be due in part to the need for specific infrastructures and human resources.Systematic review registrationPROSPERO CRD42020212454.

Full field electroretinography with skin electrodes to diagnose inherited retinal disease in pediatric patients

A single-site retrospective study was undertaken to validate a handheld electroretinogram (ERG) system utilizing skin electrodes to complete full-field ERGs as a stand-alone test in the workup for inherited retinal disease.

Ana o 3 sIgE and diagnostic algorithms reduce cost of cashew allergy diagnosis in children compared with skin prick test: Acost comparison analysis.

In the absence of a clear clinical history of reaction, diagnosis of cashew allergy using skin prick tests (SPT) or cashew-specific IgE requires a high number of oral food challenges (OFC). By using Ana o 3 sIgE alone, or a two-step diagnostic algorithm using cashew sIgE followed by Ana o 3 sIgE, there is a reduced need for OFC. We aimed to perform a cost comparison for both of these approaches compared with cashew SPT alone. Pooled individual-level data from 6 studies were used to determine diagnostic accuracy and OFC rate. Two studies used cashew SPT (n=567, 198 allergic), with 95% positive and negative predictive values of ≥12 mm and <3 mm. Four studies were included in the pathways for Ana o 3 sIgE alone or a 2-step algorithm incorporating cashew and Ana o 3 sIgE (n=271, 156 allergic). Cut-offs used were ≥8.5kUA/L and ≤0.1kUA/L for cashew sIgE and ≥0.35kUA/L and ≤0.1kUA/L for Ana o 3 sIgE. Costs were constructed based on unit prices from hospital inpatient admissions, expenses incurred by families, individual patient data on allergic reaction types and rates, and adrenaline autoinjector carriage, applying a health system perspective. Modeled data through the Ana o 3 pathway resulted in a 46.43% cost reduction (€307,406/1000 patients) compared with using cashew SPT alone (€573,854/1000 patients). The 2-step algorithm resulted in a 44.94% cost reduction compared with SPT alone (€315,952.82/1000 patients). Both the Ana o 3 pathway and 2-step algorithm resulted in a 79%-80% reduction in OFCs compared with SPT. Using Ana o 3 as a standalone test for cashew allergy diagnosis or a 2-step algorithm incorporating cashew sIgE and Ana o 3 sIgE is accurate and results in a large reduction in both OFCs and health system costs compared with cashew SPT alone.

Array genotyping as diagnostic approach in medical genetics.

Genotyping arrays are by far the most widely used genetic tests but are not generally utilized for diagnostic purposes in a medical context. In the present study, we examined the diagnostic value of a standard genotyping array (Illumina Global Screening Array) for a range of indications. Applications included stand‐alone testing for specific variants (32 variants in 10 genes), first‐tier array variant screening for monogenic conditions (10 different autosomal recessive metabolic diseases), and diagnostic workup for specific conditions caused by variants in multiple genes (suspected familial breast and ovarian cancer, and hypercholesterolemia). Our analyses showed a high analytical sensitivity and specificity of array‐based analyses for validated and non‐validated variants, and identified pitfalls that require attention. Ethical‐legal assessment highlighted the need for a software solution that allows for individual indication‐based consent and the reliable exclusion of non‐consented results. Cost/time assessment revealed excellent performance of diagnostic array analyses, depending on indication, proband data, and array design. We have implemented some analyses in our diagnostic portfolio, but array optimization is required for the implementation of other indications.

What are the predictors of TOMM failure in clinical TBI populations? A retrospective analysis.

To determine base rates of invalid performance on the Test of Memory Malingering (TOMM) in patients with traumatic brain injury (TBI) undertaking rehabilitation who were referred for clinical assessment, and the factors contributing to TOMM failure. Retrospective file review of consecutive TBI referrals for neuropsychological assessment over seven years. TOMM failure was conventionally defined as performance <45/50 on Trial 2 or Retention Trial. Demographic, injury, financial compensation, occupational, and medical variables were collected. Four hundred and ninety one TBI cases (Median age = 40 years [IQR = 26-52], 79% male, 82%severe TBI) were identified. Overall, 48 cases (9.78%) failed the TOMM. Logistic regression analyses revealed that use of an interpreter during the assessment (adjusted odds ratio [aOR] = 8.25, 95%CI = 3.96-17.18), outpatient setting (aOR = 4.80, 95%CI = 1.87-12.31) and post-injury psychological distress (aOR = 2.77, 95%CI = 1.35-5.70) were significant multivariate predictors of TOMM failure. The TOMM failure rate for interpreter cases was 49% (21/43) in the outpatient setting vs. 7% (2/30) in the inpatient setting. By comparison, 9% (21/230) of non-interpreter outpatient cases failed the TOMM vs. 2% (4/188) of inpatient cases. TOMM failure very rarely occurs in clinical assessment of TBI patients in the inpatient rehabilitation setting. It is more common in the outpatient setting, particularly in non-English-speaking people requiring an interpreter. The findings reinforce the importance of routinely administering stand-alone performance validity tests in assessments of clinical TBI populations, particularly in outpatient settings, to ensure that neuropsychological test results can be interpreted with a high degree of confidence.

무인 수상선의 수중 추진기 고장 진단 연구를 위한 고장 특성 인자 선정 및 실험

As interest in unmanned vessel research has increased, emphasis on autonomous navigation capability and the sustainability of normal operation has been highlighted. However, research on fault detection and diagnosis (FDD) for unmanned surface vehicles (USVs) is insufficient compared with research on land machinery or unmanned aerial vehicles. Among prior studies on USV FDD, intensive analysis or diagnostics for individual elements with high failure probability were barely conducted. This study focus on fault detecting features of a USV thruster, one of the most failure-prone elements other than internal causes or software malfunctions. A hypothesis for thruster fault detecting features was made based on general thruster-related equations; the features were tested on a stand-alone thruster test to assess the feature’s acceptability. However, a stand-alone thruster test lacks important effects such as structural vibratory influence of an actual USV, thruster load difference due to inflow velocity and wave-induced vibrations as the USV slides on the water’s surface. Hence, USV capable of acquiring fine quality real-time data for FDD practice was developed, and a surface driving test in a water basin was conducted to confirm the eligibility of the selected features.

Prevalence of iron deficiency anaemia in patients of cholelithiasis undergoing laparoscopic cholecystectomy

Background: Gallstone disease (GSD) is a very common condition worldwide and the key event in the cholesterol stone formation is the supersaturation of bile with cholesterol. The role of trace elements like iron, calcium has been suggested in the pathogenesis of gallstones. Both iron deficiency and GSD are more prevalent in India. With this background, we studied the frequency of iron deficiency anaemia in GSD patients.Methods: This prospective observational study enrolled 150 adult patients undergoing laparoscopic cholecystectomy for symptomatic GSD in a north-Indian tertiary care hospital. Complete hemogram, serum ferritin, iron and unbound iron-binding capacity (TIBC) were performed in all patients. To simplify interpretation, anaemia was defined as Hb &lt;12 gm/dl; iron deficiency was defined as either ferritin value lower than the reference range, or, if the ferritin was within the reference range, reduced % transferrin saturation with normal-or-high TIBC.Results: Anaemia was present in 66% and 77.3% were having iron deficiency; of which 84.5% were females. Iron deficiency with anaemia was present in 85.3%; therefore remaining patients had latent iron deficiency. Serum ferritin was normal or raised in 52 (68.1%) patients with iron deficiency, indicating that it is insensitive as a stand-alone test for iron deficiency.Conclusions: At a public health level, our results may suggest that addressing the problem of endemic iron deficiency may also reduce the possible development of GSD in the community. Thus, pre-operative assessment of iron status appears to be a cautious choice in all patients planned for cholecystectomy as indirectly it will address the problem of anaemia in the population.

Pediatric Feeding Disorder in Early Intervention: Expanding Access, Improving Outcomes, and Prioritizing Responsive Feeding

Purpose: Pediatric feeding disorder (PFD), like many childhood medical conditions, is likely to negatively impact a child's growth and development, daily learning opportunities, and family functioning. Parents who have children with a diagnosis of PFD may not yet know the most effective way to feed their children and often experience negative emotions surrounding mealtimes. These families may receive therapy services through early intervention (EI) programs. In many states, there are barriers that limit access to programs and provision of high-quality care for this population. These barriers include the lack of an approved single feeding-related diagnosis that renders a child automatically eligible, lack of approved stand-alone feeding-specific testing tools with which to determine eligibility, lack of educational and clinical experience requirements for providers, and considerable variation in service provision. Method: This clinical focus article reviews the definition of PFD, the multifaceted needs of families and children in EI, support for use of responsive feeding in treatment of PFD, alignment of responsive feeding strategies with EI principles, and barriers limiting access to consistent, high-quality EI services for children with PFD. Several changes to EI programs are proposed to address these barriers. Conclusions: Use of PFD as an automatically qualifying diagnosis for EI programs and use of approved stand-alone feeding-specific assessment tools could establish more consistent and specific eligibility standards for this population, likely expanding early access to support and improving outcomes. EI provider clinical experience and training requirements would likely lead to more consistent and high-quality, evidence-based service provision. Required training should include the use of methods such as routines-based intervention, parent coaching, and anticipatory guidance to support implementation of responsive feeding practices during mealtime routines.

Predicting the Performance of Solar Photovoltaic Thermal Water Collectors Using Hybrid Fuzzy Logic Expert System

ABSTRACT This study presents a hybrid Mamdani fuzzy logic expert system (H-M-FLES), which predicts the overall performance delivered by three differently connected solar photovoltaic thermal water collector systems (S-PV/T-W-C-S). For training the FLES, real-time experiments are conducted with three differently connected S-PV/T-W-C-S (stand-alone, series and parallel) test rigs at Tiruchirappalli, India. Then, the trained model was tested and validated against the real-time experimental results. The results predicted by this newly proposed H-M-FLES is in-line with the experimental results with the overall prediction accuracy of 95.50%. Also, the prediction accuracy by this H-M-FLES is 0.52% higher than that of the available FLES based literature.

Reduction of disinfection efficacy of contact lens care products on the global market in the presence of contact lenses and cases

ObjectiveSight-threatening infections can be caused by pathogenic micro-organisms colonising the cornea, leading to microbial keratitis (MK). These micro-organisms can be introduced to the eye via improper contact lens use and...

Differential Propagation Delay Measurement of RSFQ Library Cells Using Ring Oscillators

Performing comprehensive timing characterization of library cells and establishing their model-to-hardware correlation are essential for building robust integrated circuits and scaling circuit complexity. To measure the propagation delay of fabricated library cells, we have designed a differential delay measurement scheme using SFQ ring oscillators. The reference and design-under-test (DUT) rings are designed using circuit elements that are either common to both rings or are of nominally similar design, except for the DUT. By inserting a single pulse in the ring, the oscillation period is measured using two methods: (1) direct voltage measurement, and (2) frequency measurement using a frequency divider followed by an SFQ-to-DC converter. Subtracting delay of the two rings gives us the propagation delay of the DUT. A 1 cm by 1 cm chip and another 5 mm by 5 mm chip, incorporating stand-alone ring oscillator test structures for different library cells, have been fabricated in the MIT-LL SFQ5ee process. The chips also contain test circuits to validate two variants of the input/output multiplexing scheme that facilitate reducing the pads requirement. Two copies of a chip with fifteen DUTs were tested. The measured and simulated results for the voltage and frequency of the ring are compared. The simulations account for critical current density ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c</i> ) and sheet resistance (Rs) fabrication parameters. In addition, we have used the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c</i> as a single free parameter to get a better matching with measurement results. For one of the chips, a 15% higher <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c</i> in simulations results in better matching with measured frequency results for all the DUTs. For example, the discrepancy between simulated and measured DUT ring frequency for the NOT cell was reduced from 19% to 1% when the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c</i> was changed from nominal to 15% higher in simulations. Detailed measurement and simulation results for several DUTs are presented.

MP51-08 DOES A POSITIVE MULTI-PARAMETRIC MRI ALWAYS WARRANT PROSTATE BIOPSY? THE IMPORTANCE OF INTEGRATING CLINICAL AND IMAGING DATA BASED ON A LARGE, MULTI-INSTITUTIONAL SERIES

MP51-08 DOES A POSITIVE MULTI-PARAMETRIC MRI ALWAYS WARRANT PROSTATE BIOPSY? THE IMPORTANCE OF INTEGRATING CLINICAL AND IMAGING DATA BASED ON A LARGE, MULTI-INSTITUTIONAL SERIES

Detection of 16S rRNA gene for rapid identification of bacterial pathogens causing peritonitis in patients on continuous ambulatory peritoneal dialysis

PurposePeritonitis is the most important complication with high rate of morbidity and mortality in patients on continuous ambulatory peritoneal dialysis (CAPD) despite the success and advances. Rapid and accurate identification of pathogens causing peritonitis in a CAPD patient is essential for early targeted treatment. The aim of the study was to evaluate the role of 16S rRNA gene and ITS region PCR and sequencing in detecting bacterial and fungal pathogens from the dialysate of patients undergoing CAPD. MethodsFifty eight peritoneal dialysate from suspected cases of peritonitis on CAPD were subjected to conventional culture as per the ISPD guidelines and automated culture system. A conventional PCR was performed to detect the 16S rRNA gene and ITS region. Sequencing and analysis were performed to identify the etiological agent from the remaining dialysate. ResultsAmong the 58 dialysate fluid, the etiological agents were identified in 8(14%) samples by conventional culture, 28(48%) by automated culture and 47(81%) by 16S rRNA sequencing and analysis. In 8 samples there was discordance in the results of the culture and 16S rRNA PCR. BLAST search of nine sequences obtained from 16S rRNA PCR revealed that these sequences matched best with uncultured bacterial clones. In eleven samples the sequence failed. ConclusionThe molecular tool 16S rRNA gene and ITS region PCR and sequencing cannot be used as a standalone test as it lacks sensitivity to identify some bacterial species due to high genetic similarity in some cases and inadequate database in GenBank. However, it could be used as a supplementary test to the culture method especially in the diagnosis of culture negative peritonitis.

Predictive value of doppler cerebroplacental ratio for adverse perinatal outcomes in postdate pregnancies in Northwestern Nigeria.

Postdate pregnancy is a very common obstetric condition, increasing the risk of perinatal morbidity and mortality from uteroplacental insufficiency. To determine the predictive values of Doppler cerebroplacental ratio (CPR), that is, the ratio between middle cerebral artery (MCA) and UA pulsatility indices (UA PI), and other potential velocimetric predictors of adverse perinatal outcomes in women with postdated pregnancies. A prospective cohort study was conducted on consenting 212 low-risk pregnant women beyond 40 weeks' gestational age. The pulsatility indices of MCA, UA, and CPR as well as non-stress tests (NST) and amniotic fluid index (AFI) were measured and recorded. The women were divided into two groups based on the presence or absence of adverse perinatal outcome defined as: meconium stained liquor, meconium aspiration syndrome, perinatal asphyxia, cesarean section for suspected fetal distress, and perinatal death. : Of the 200 women whose data were available for analysis, 40 (20%) of them had adverse perinatal outcome and 160 (80%) had normal perinatal outcome. The CPR showed statistically significant difference in predicting adverse perinatal outcome (P < 0.001). CPR had a better predictive value than UA-PI and outperformed MCA-PI and NST for adverse perinatal outcomes. The sensitivity, specificity, negative predictive value (NPV), and accuracy of prediction of adverse perinatal outcomes by CPR were 90%, 81.25%, 97.01%, and 83%, respectively. The Doppler CPR shows the highest diagnostic accuracy in prediction of adverse perinatal outcome in pregnant women after 40 weeks' gestation than UA PI and velocimetric indices when used as stand-alone test.

A method for verifying the model of tank operational pressurization process during development of propellant supply system in liquid rocket engines of launch vehicle propulsion systems

During development of propulsion systems for launch vehicles, in order to verify the design results, standalone developmental tests of propellant supply system components were run in specially designed test setups outfitted with the required instrumentation. As an example of such work, this paper describes the experience of standalone developmental testing of operational pressurization of propellant tanks. During tests in the constructed test setups, heat and mass exchange processes were tried out with simulation of design modes of operational pressurization of propellant tanks filled with oxygen and hydrogen. As a result of these tests, a rationale was provided for selection of working mediums as the pressurization gas, design and characteristics of gas injection into propellant tanks, a method for evaluating the efficiency of the pressurization process. Empirical dependences were obtained that were used as the boundary conditions in the models for practical calculations for refining the modes and evaluating the efficiency of the propellant supply subsystem of propulsion systems. The paper calls attention to the need to use for the purpose of development of the propellant supply systems that involves computer simulations the results of such earlier work when designing advanced rocket propulsion systems. Key words: propulsion system, propellant supply system, development of pressurization process, test setup, pressurization gas, propellant components, heat and mass transfer intensity, process efficiency, liquid surface sloshing, computer simulations.