Cut-off Ratio Research Articles

DEVELOPING CEREBROSPINAL flUID METABOLOMIC BIOMARKERS FOR MINIMAL RESIDUAL DISEASE AND RELAPSE IN EPENDYMOMA AND MEDULLOBLASTOMA

Abstract AIMS Relapse rates of 30% and 50% in medulloblastoma and ependymoma lead to poor outcomes for paediatric brain tumours. Occurring usually within two years, relapses imply minimal residual disease (MRD) is present below the imaging detection threshold. Patient outcomes might be improved by diagnosing MRD using a sensitive, minimally invasive cerebrospinal fluid (CSF) liquid biopsy, as CSF is proximal to tumour. Metabolites arising from aberrant cancer metabolism may be biomarkers in CSF. METHOD With only 25µl CSF, extracted with 75µl methanol, liquid chromatography coupled with tandem high-resolution mass spectrometry (LC-MS/MS) could differentiate these paediatric brain tumours (n=47; day 14 post-surgery) from controls (n=49). RESULTS Fourteen metabolites were increased in abundance in tumours and four decreased compared to controls. These included amino acids and derivatives (n=8), metabolites in one carbon metabolism (n=1), carnitine cycle (n=2), aerobic glycolysis (n=2), purine catabolism (n=2), ascorbate degradation (n=1) and creatinine synthesis (n=2). From those, betaine/creatinine ratio gave an area under the curve (AUC) of 0.96 (excellent) in receiver operating curve analysis. Using a cut-off ratio of 0.1775 for discriminating brain tumours from controls, had sensitivity and specificity of 92% and 89%. Specifically identifying tumours, a ratio of betaine/threonate with cut-off 2.1514 discriminated ependymomas from controls (sensitivity/specificity 92%/91%). A ratio of malic acid/hypoxanthine with cut-off 0.04429 discriminated medulloblastomas from controls (sensitivity/specificity 100%/98%). Medulloblastomas (n=14) were largely similar to ependymomas (n=33); nevertheless, three metabolites met the criteria of corrected p<0.05. A ratio of glutarate semialdehyde/malic acid with cut-off 0.04243 discriminated ependymomas from medulloblastomas (sensitivity/specificity 79%/82%) in a good model (AUC 0.85). CONCLUSION This is the first report of CSF metabolites in ependymoma. Ratios between metabolites levels could be useful as biomarkers to detect brain tumours and distinguish brain tumour type specifically and sensitively. Further work to develop a liquid biopsy test for the detection of MRD is ongoing.

A-311 Evaluating the Predictive Value of the sFlt-1/PlGF Ratio in Hypertensive Pregnancies for Preeclampsia

Abstract Background Preeclampsia (PE) is a hypertensive pregnancy disorder affecting around 5% of all pregnancies, and it continues to be a leading cause of maternal and neonatal morbidity and mortality in the United States. The incidence of hypertensive pregnancies is on the rise, attributed to the increasing prevalence of obesity and chronic hypertension. The development of a straightforward diagnostic test to accurately differentiate PE from gestational or chronic hypertension is crucial to avoid unnecessary hospitalizations. Despite the ongoing development of prediction models for PE, conventional clinical and laboratory measures have not been effective in predicting disease progression. Recent research has focused on the ratio of two serum biomarkers: soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), particularly in patients with a clinical suspicion of PE in acute settings. These studies have shown promise, with many indicating that the sFlt-1/PlGF ratio can effectively predict the presence or absence of PE. This study was conducted to assess the predictive value of the sFlt-1/PlGF ratio in pregnancies complicated by hypertension, aiming to contribute to the early detection and management of PE. Methods Pregnant individuals with hypertensive disorders at or above the age of 18 receiving prenatal care at NewYork-Presbysterian-Weill Cornell Hospital were enrolled in this study. We measured the levels of sFlt-1 and PlGF using fully automated Elecsys immunoassays (Roche Diagnostics). Subsequently, a prospective analysis of the serum sFlt-1/PlGF ratio was performed. A receiver operating characteristic (ROC) curve was used to calculate the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the ratio in predicting PE. To assess the prognostic accuracy of the sFlt-1/PlGF ratio, patients were randomly assigned to a development and a validation cohort at a ratio of 30:70. Results We collected a total of 137 serum samples of hypertensive pregnancies, with all ≥20 weeks of gestational age (GA). Of these, 47 (34.3%) developed PE within 2 weeks. The samples were divided into two cohorts: 98 were included in the development cohort, and 39 in the validation cohort. Within these groups, 34 (34.7%) of the development cohort and 13 (33.3%) of the validation cohort developed PE within 2 weeks, respectively. In the development cohort, the median sFlt-1/PlGF ratio was 85 (Interquartile range, [IQR], 44-164) among pregnant women who developed PE within 2 weeks. This was significantly higher compared to a median ratio of 8 (IQR, 3-35) observed in those who did not develop PE (p<0.001). The area under the ROC curve was 0.87, indicating good discriminative ability. An optimized cutoff ratio of 38 was determined, based on the max of combined sensitivity and specificity. When applied into the validation cohort, this cutoff yields a 90% (95% confidence interval [CI], 70-97) NPV and 58% (95%CI, 37-76) PPV with an 85% sensitivity (95%CI, 58-96) and a 69% specificity (95%CI, 50-83). Conclusions In women with a hypertensive disorder of pregnancy presenting GA≥20 weeks of gestation, the measurement of serum sFlt-1/PlGF ratio demonstrated clinical value in predicting the development of PE.

Antibody response to SARS-CoV-2 natural and breakthrough infection in patients undergoing maintenance hemodialysis: A prospective cohort study over 4 months

BackgroundPatients undergoing maintenance hemodialysis (MHD) are susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the antibody response of these patients to natural and breakthrough infections remains poorly understood. MethodsBetween January 15, 2023, and February 15, 2023, a total of 53 patients undergoing MHD and diagnosed with SARS-CoV-2 infection at The Affiliated Hospital of Hangzhou Normal University were enrolled. They were categorized into the natural (n = 40) and breakthrough infection groups (n = 13) based on their vaccination status before infection. Comprehensive data, including basic clinical information, vaccination status, and routine post-infection blood parameters, were collected from all participants. Blood specimens were drawn monthly after infection, and SARS-CoV-2 receptor-binding domain (RBD) immunoglobulin (Ig) G and IgM tests were conducted. The study included continuous follow-up over 4 months. ResultsDuring the acute phase of infection, the SARS-CoV-2 RBD IgM positivity was 5 % in patients undergoing MHD who were naturally infected and 15.4 % in those with breakthrough infections. Four months after infection, SARS-CoV-2 RBD IgG positivity in patients with natural and breakthrough infection was 77.5 % and 100 %, respectively. Patients undergoing MHD with breakthrough infection exhibited higher SARS-CoV-2 RBD IgG titers (751.21 signal-to cutoff ratio, S/CO [interquartile range, IQR, 30.54–1173.63]) than those with natural infections (3.43 S/CO [IQR, 1.12–15.6]) (p < 0.0001). No significant differences were observed in SARS-CoV-2 RBD IgG between males and females or among those aged <70 and ≥70 years. Patients who received three doses of the inactivated vaccine produced significantly higher SARS-CoV-2 RBD IgG levels after infection than those who received one or two doses; these differences were significant. ConclusionsAlthough patients undergoing MHD exhibit a low rate of SARS-CoV-2 RBD IgM positivity following infection, those vaccinated with inactivated vaccines can generate elevated SARS-CoV-2 RBD IgG levels, particularly those who receive three doses.

Experimental investigation of online solving for critical valve opening for eliminating severe slugging in pipeline-riser systems

In an offshore pipeline-riser system, the critical opening of choke valve, i.e., the maximum permanent opening to eradicate severe slugging, plays an important role in both pipeline design and offshore oil and gas production processes. However, solving critical opening online in an offshore oil field is very difficult because only topside measurements are available and system information such as inlet gas–liquid flow rates and transfer functions are unavailable or far from precise. In order to cope with this problem, manually traversal experiments were first conducted in a large-scale experimental system consists of a 114-m horizontal pipeline, an 18.7-m downward-inclined pipeline with an inclination angle of −5˚ and a 16.3-m riser. Based on the results, a new process variable characterizing cut-off ratio of outflow and a new valve parameter describing the influence of valve on flow were derived. An approximate linear relation between these two parameters was found, with which critical openings can be calculated by processing real-time data. Finally, a control scheme was designed to overcome the calculation errors and solve for critical openings on line. The performance was validated by automatic control experiments.

Comparison of objective visual quality between SMILE and FS-LASIK in moderate-to-high myopia.

This study aims to compare the changes in the corneal wavefront aberrations and the objective visual quality resulting from two types of eye surgery-small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK)-in patients with moderate-to-high myopia. A prospective analysis was performed on 98 eyes of 51 patients who underwent SMILE. Additionally, 88 eyes of 45 patients who underwent FS-LASIK were analyzed. All patients underwent ocular examination preoperatively and at 1 day, 1 week, 1 month, and 3 months postoperatively. Corneal aberrations and objective visual quality were measured using the Optical Quality Analysis System II (OQAS II) and Optical Path Difference Scan III (OPD-Scan III). At postoperative 1 day and 1 week, there was a statistically significant difference in uncorrected distance visual acuity (UDVA) between SMILE and FS-LASIK (P < 0.05). Postoperative spherical (S), cylinder (C) and spherical equivalent refraction (SE) were similar between the two groups (P > 0.05). In both groups, the absolute magnitude of total higher-aberrations (tHOA), piston, vertical tilt, vertical coma, and spherical aberration (SA) increased after surgery compared to preoperative values (P < 0.05). There was no significant difference in Δhorizontal tHOA, Δhorizontal tilt, Δhorizontal coma, and Δhorizontal trefoil between the two groups (P > 0.05), and the FS-LASIK had higher Δvertical trefoil and ΔSA (P < 0.05) but lower Δpiston, Δvertical tilt, and Δvertical coma than the SMILE group (P < 0.05). There was a rise in objective scattering index (OSI) and a decline in both modulation transfer function (MTF) cutoff and Strehl ratio (SR) after surgery compared to preoperative values in both groups (P < 0.05). There was a statistically significant difference in the OSI at 1 day and 3 months between the two groups (P < 0.05). Postoperative MTF cutoff and SR were similar between the two groups (P > 0.05). Postoperative OSI was positively correlated with corneal tHOA (0.261 ≤ R ≤ 0.483, P < 0.05) and was negatively correlated with vertical tilt and vertical coma (-0.315 ≤ R ≤ -0.209, P < 0.05) in both groups. While both SMILE and FS-LASIK can effectively correct moderate-to-high myopia, there is an increase in corneal aberrations and a postoperative delay in objective visual quality. The cornea may require a longer recovery period in the SMILE. OPD-Scan III combined with OQAS II is a useful supplementary inspection for assessing the optical quality following refractive surgery.

Prognostic importance of preoperative albumin-to-alkaline phosphatase ratio in colorectal cancer patients.

&lt;b&gt;Introduction:&lt;/b&gt; Colorectal cancer (CRC) prognosis is typically determined based on clinical stage and histopathological findings, yet patients with the same stage and histological structure can exhibit varying survival outcomes. This highlights the need for additional prognostic biomarkers. Serum biomarkers are gaining increasing significance due to their affordability and accessibility. The albumin-alkaline phosphatase ratio (AAPR) has been associated with prognosis in hepatocellular and gastric cancers, but its role in CRC remains underexplored.&lt;b&gt;Aim:&lt;/b&gt; This study aimed to evaluate the effect of the albumin-alkaline phosphatase ratio (AAPR) on the prognosis of patients with colorectal cancer (CRC).&lt;b&gt;Material and method:&lt;/b&gt; Data from 358 patients who had undergone surgery for CRC were analyzed retrospectively to identify factors that could predict overall survival (OS). The Roc-Curve test was applied to determine the power of the preoperative AAPR in predicting mortality. Kaplan Meier and log-rank tests were used to examine the survival times of the patients.&lt;b&gt;Results:&lt;/b&gt; Our findings revealed that an albumin-alkaline phosphatase cut-off ratio above 0.67 predicted mortality with a sensitivity of 17.54% and a specificity of 92.22%. Although patients with a lower AAPR exhibited a slightly shorter mean survival time compared to those above the cut-off value, this difference did not reach statistical significance (P = .112).&lt;b&gt;Conclusions:&lt;/b&gt; The results of this study did not provide evidence to support the AAPR as a potential prognostic factor in patients with colorectal cancer.

Role of IgM/ IgG Ratio in Distinguishing Primary and Secondary Dengue Viral Infections: A Cross-Sectional Study.

Objectives In recent years, Uttarakhand, a state in North India has become one of the prime spots for tourism all over the world. Thereby, a tremendous increase in the epidemics of dengue infection has been observed recently. Secondary dengue causes more severe disease in comparison with primary, thus to differentiate the two is very crucial. We aim to find out the cut-off values of the IgM:IgG ratio for early detection of secondary dengue which could further help clinicians to prevent the complications. Methods A cross-sectional study was conducted over one year involving around 936 suspected cases of dengue. Samples were tested using the commercially available capture enzyme linked Immunosorbent assay (ELISA) method for IgM and IgG. Real-time and nested polymerase chain reaction (PCR) tests were also done to find out the prevalent serotype. IgM:IgG ratio was evaluated by using receiver operating characteristic curve analysis for the differentiation of primary and secondary dengue. Results Among the total 91 serologically confirmed dengue patients, forty-seven (51.6%) were found to be primary, and forty-four (48.4%) were secondary dengue infections with male preponderance. Using the WHO diagnostic criteria, patients with dengue fever (DF) without warning signs added up to 51.6%, with warning signs 42.9% and severe dengue 5.5% of the total cases. The cut-off ratio of IgM:IgG ratio = 1.59 found the best discrimination between primary and secondary infection. Forty out of ninety-one (44%) patients exhibited ratios of > 1.59 whereas the rest fifty-one (56%) exhibited ratios of < 1.59. Dengue virus - 2 (DENV- 2) was found to be the most prevalent serotype. Conclusion Our study recommends the cut-off values for IgM:IgG ratio as 1.59. Therefore it is hoped that this will guide the clinicians to early distinguish between primary and secondary dengue. Furthermore, it can reduce morbidity and mortality because of dengue infections in the future.

Effect of Lens Deviation on Peripheral Defocus and Optic Quality in Adolescents With Moderate and Severe Myopia.

The aim of this study was to analyze the effects of lens deviation on peripheral defocus and optic quality in adolescents with moderate and severe myopia. This prospective study enrolled 81 children (81 eyes). The spherical equivalent was -5.0≤SE≤-6.0 diopter. The participants were divided into two subgroups based on their eccentricity (inferior temporal) after wearing the lenses for 12 months. Between them, the low eccentric subgroup (A) had a total eccentric distance of less than 0.5 mm, and the moderate and severe eccentric subgroup (B) had a total eccentric distance of ≥0.5 mm. Peripheral defocus and eccentricity were measured before and after wearing the lenses, and the Spearman test was used to compare the parameters. Parameters such as the total peripheral defocus (TRDV) were significantly lower in subgroup B than in subgroup A after 12 months of orthokeratology lens usage. The axial length growth (ΔAL) in subgroup A was higher than that in subgroup B. Axial length growth, TRDV, and other parameters were significantly associated with eccentricity. The modulation transfer function cutoff and Strehl ratio were also significantly associated with eccentricity. Greater eccentricity within a certain range can induce greater periretinal defocus and improve the ΔAL.

Incidence and risk factors of complications during central venous access devices removal in children.

To quantify the rates and identify risk factors for the complications of central venous access devices (CVADs) removal in children. Retrospective (2018-2023) review of children undergoing CVADs removal at a single institution. Data are reported as frequency, percentages and median. Logistic regression analysis was used to identify risk factors associated with difficult removal. Receiver Operating Characteristic Curve (ROC) analysis was conducted to identify the age cut-off and positive likelihood ratio (+LH) for the indwelling time associated with complicated removal. p-Value <0.05 were considered statistically significant. We identified 208 CVAD removals with a median age of 7.2 (0.2-18.4) years including 116 (55.8%) males. The median CVAD placement duration was 1.26 years (0.4-5.7) years. Indications for insertion included acute lymphoblastic leukaemia (ALL; 78/208, 37.5%), lymphomas (31/208, 14.9%), other malignancies (58/208, 27.9%). Removal indications included completion of treatment (144/208, 69.2%), infection (22/208, 10.6%), malfunction (7/208, 3.4%) and other reasons (35/208, 16.8%). There were 20 (9.6%) complications characterised by difficulty removing the CVAD. Complicated removals were more likely to occur in children with ALL as the primary diagnosis (p = 0.001); independently of the indication for insertion, longer indwelling time was associated with higher risk of complicated removal (p < 0.001). Indwelling time >2.09 years was associated with a 2.87 increased risk of difficult removal. In our experience, almost 10% of CVAD removals in children result in complications. These findings are associated with an indwelling time >2 years; strategies to prevent complicated removals should be considered in children requiring long-term central venous access.

Angiographic Characteristics in Mild Familial Exudative Vitreoretinopathy with Genetically Confirmed Autosomal Dominant Inheritance

PurposeTo determine the ultra-widefield fluorescein angiographic (UWFA) characteristics of patients with mild familial exudative vitreoretinopathy (FEVR) who had been confirmed to have pathogenic variants of the autosomal dominant (AD) genes of FEVR. DesignSingle center, observational case series. Subjects and ControlsThirty-seven patients with mild FEVR from 27 families who had pathogenic variants of the Norrin/β-catenin genes were studied. The controls consisted of 32 family members who had been confirmed not to carry the pathogenic variants or had heterozygous variants of the autosomal recessive inheritance gene. MethodsSixty-four UWFA images from the patients were compared to 60 UWFA images from the controls. The relative length of the temporal retina to the peripheral avascular retina was determined. The cut-off ratio of the relative lengths for a clinically significant avascular retina (csAR) associated with AD-FEVR was determined using the receiver operating characteristic (ROC) curves. Main Outcome MeasuresThe presence or absence of six peripheral vascular changes: csAR, V-shaped vascular notch, brushy vascular ends, vascular stain, loop vessels and/or anastomosis, and capillary telangiectasia were compared between the patients and the controls. ResultsThe csAR was set at >12% of the length from the ora serrata to the optic disc. The AD-FEVR patients had more frequent retinal changes than the controls for the V-shaped vascular notch (69% vs 2%, P <0.001), brushy vascular ends (78% vs 3%, P <0.001), csAR (83% vs 22%, P <0.001), and vascular stain (70% vs 33%, P <0.001). Loop vessels and/or anastomosis of peripheral vessels were found significantly less frequently in the patients than in the controls (39% vs 73%, P <0.001). No significant difference was found for capillary telangiectasia between the two groups. The combination of the V-shaped vascular notches, brushy vascular ends, and csAR had a sensitivity of 82.8% and specificity of 98.3% with the highest ROC curve of 0.9. ConclusionsThe combination of V-shaped vascular notch, brushy vascular ends, and csAR can be used as a biomarker for AD-FEVR patients who have pathogenic variants of the Norrin/β-catenin genes. These findings will allow more accurate segregation analysis in FEVR families and allow better genetic counseling.

Hepatitis B screening in hematology patients receiving intravenous immunoglobulin.

Transient positivity for hepatitis B core antibody (Anti-HBc) following intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin exposure is a well-described phenomenon. The aim of this study was to retrospectively review Hepatitis B viral screening practices in IVIG recipients in a hematology specific cohort at a single center. Electronic databases were analyzed to identify all hematology patients who received IVIG from September 2022 to March 2022 at a single Irish center (n = 43). The proportion of patients that had a baseline anti-HBc tested prior to IVIG receipt was assessed as well as the proportion of patients that developed a transiently positive anti-HBc following IVIG exposure. Data were also collected relating to signal cut-off ratios in patients with detectable anti-HBc post-IVIG. 58.1% of patients had at least one serological hepatitis B viral test sent prior to IVIG exposure. Anti-HBc was the least common serological investigation performed prior to IVIG exposure (21% of recipients). A positive or equivocal "low level antibody" was identified in 15% of recipients and this was proven to be transient in all cases. The minority of hematology patients had a baseline anti-HBc assessed prior to IVIG exposure. All patients in this study had the potential to require further immunosuppressive therapies, which could be limited by a misleading anti-HBc result. We therefore advocate for baseline anti-HBc testing to be performed prior to IVIG exposure in hematology patients and for cautious interpretation of anti-HBc results taking into account signal cut-off ratios post-IVIG exposure.

Circular RNA hsa_circ_0002268 (PHACTR1) Is Specific to Gestational Diabetes Mellitus in a Polish Pregnant Population.

Gestational diabetes mellitus (GDM) is an intolerance of carbohydrate of any degree, which appears for the first time or is diagnosed during pregnancy. The objective of this study is to assess the differences in circular RNA (circRNA) in a Polish pregnant population with and without GDM. A total of 62 pregnant women, 34 with GDM and 28 controls, were enrolled in the study. Total RNAs were extracted from plasma and reverse transcription to complementary DNA (cDNA) was performed. A panel covering 271 amplicons, targeting both linear and circular as well as negative control gene transcripts, was used. Next-generation sequencing was used to evaluate the circRNA quantity. Data analysis was performed using the Coverage Analysis plugin in the Torrent Suite Software (Torrent Suite 5.12.3). A two-step normalization was performed by dividing each transcript read count by the total number of reads generated for the sample, followed by dividing the quantity of each transcript by β-actin gene expression. Both circular and linear forms of RNAs were independently evaluated. A total of 57 transcripts were dysregulated between pregnant women with GDM and controls. Most of the targets (n = 25) were downregulated (cut-off ratio below 0.5), and one target showed a trend toward strong upregulation (ratio 1.45). A total of 39 targets were positively correlated with fasting plasma glucose (FPG), but none of the tested targets were correlated with insulin, CRP or HOMA-IR levels. Among the pregnant women with gestational diabetes, the relative quantity of hsa_circ_0002268 (PHACTR1) was approximately 120% higher than among healthy pregnant women: 0.046 [0.022-0.096] vs. 0.021 [0.007-0.047], respectively, (p = 0.0029). Elevated levels of hsa_circ_0002268 (PHACTR1) might be specific to the Polish population of pregnant women with GDM, making it useful as a potential molecular biomarker in the management of GDM in Poland.

Experimental investigation of the performance attributes of a double pipe heat exchanger equipped with baffles of conventional or flower layouts

In industrial heat management, the design of baffles within heat exchangers is crucial. They guide fluid flow and enhance turbulence, optimizing heat transfer. Yet, their configuration must be carefully considered to balance thermal efficiency with energy expenditure and pressure management. This research conducts practical tests on the hydrothermal attributes of a counter-flow double-pipe heat exchanger. It evaluates two baffle layouts: segmental and flower, considering baffle cut-off ratio (16.7 %≤δ ≤ 50 %), pitch ratio (8.3 %≤λ ≤ 22.2 %), flower-design relative angle (30°≤γ ≤ 90°), and operating conditions of annulus-side (2660 ≤ Rean ≤ 13110, 5.21 ≤ Pran ≤ 7.48). The findings assure that installing the baffles results in notable increases in both Nu¯an and fan. Besides, lowering baffle cut-off and pitch ratios, and increasing the relative angle of flower baffles lead to additional increases. Moreover, raising the annulus-fluid temperature reduces Nu¯an with a negligible effect on fan. Increasing Rean leads to a reduced fan and greater Nu¯an. Compared with no baffles, the maximum recorded increases in the Nu¯an and fan are 147.4 % and 60.2 %, respectively, realized by incorporating flower layout. On average, the flower baffles boost the Nu¯an by 20.8 % more than those using conventional baffles, with an average increase of 4.3 % in the fan. To judge the benefit of utilizing baffles, the Hydrothermal Performance Index (HTPI) is calculated, and its highest value is recorded as 2.23, attained by running the annular pipe at the lowest flow rate and temperature, with inserting flower baffles (δ = 16.7 %, λ = 8.3 %, γ = 90°). Finally, correlations for Nu¯an, HTPI, and fan prediction are suggested.

Experimental investigation of performance, emissions, combustion characteristics, cyclic variations, and exergy efficiency of CI engine fueled with Karanja-camphor oil blends and diesel-camphor oil blends.

This article compares the influence of blending the low-viscous oxygenated camphor oil with hydrocarbon diesel fuel and high-viscous oxygenated Karanja oil. The experiment is conducted in a four-stroke one-cylinder naturally aspirated Kirloskar compression ignition (CI) engine coupled with an eddy current dynamometer. The three types of fuel blends are prepared by blending the camphor oil with Karanja oil on the volume ratio of 30:70 (C30K70), 50:50 (C50K50), and 70:30 (C70K30), and the other three types of fuels are prepared by blending the camphor oil with diesel on the volume ratio of 30:70 (C30D70), 50:50 (C50D50), and 70:30 (C70D30). The experimental efficiency results show higher thermal efficiency of 31.86% and 30.84% for C70D30 and C70K30 at rated operating conditions. The brake-specific energy consumptions of C70D30 and C70K30 were found to be 11.29 and 11.67MJ/kWh, respectively, at rated operating conditions. The lowest CO, CO2, HC, and smoke emissions are found for C70D30 at rated operating conditions, which are 96.58%, 6.15%, 34.20%, and 7.59% lower than diesel. However, the NO emissions were found to be 27.62% higher for C70D30 than diesel at full load. The rate of pressure rise, net heat release rate, and cyclic variations were found to increase with increase in proportion of the camphor oil. The P-v diagram also confirms the lower heat addition period for the C70D30 and C70K30 with an increase in brake thermal efficiency. The actual compression ratio and the actual cutoff ratio are found to have a reasonable correlation with the thermal efficiency of the engine. The exergy efficiency of C30K70 is found higher which is 2.11% higher than diesel fuel at rated power. Second-order polynomial equations were obtained for the engine characteristics using the curve fitting method, and the characteristic equations confirmed the confidence level of 95%.

Effect of low-degree astigmatism on the objective visual quality.

To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System (OQAS). This study enrolled 46 participants (aged 23 to 30y, 90 eyes) with normal or corrected-to-normal vision. The cylindrical lenses (0, 0.5, 0.75, 1.0, and 1.25 D) were placed at the axial direction (180°, 45°, 90°, and 135°) in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism. OQAS was used to detect the objective visual quality, recorded as the objective scattering index (OSI), OQAS values at contrasts of 100%, 20%, and 9% predictive visual acuity (OV100%, OV20%, and OV9%), modulation transfer function cut-off (MTFcut-off) and Strehl ratio (SR). The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters. Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed. The increase of OSI per degree of astigmatism at 180°, 45°, 90°, and 135° axis were 0.38 (95%CI: 0.35, 0.42), 0.50 (95%CI: 0.46, 0.53), 0.49 (95%CI: 0.45, 0.54) and 0.37 (95%CI: 0.34, 0.41), respectively. The decrease of MTFcut-off per degree of astigmatism at 180°, 45°, 90°, and 135° axis were -10.30 (95%CI: -11.43, -9.16), -12.73 (95%CI: -13.62, -11.86), -12.75 (95%CI: -13.79, -11.70), and -9.97 (95%CI: -10.92, -9.03), respectively. At the same astigmatism degree, OSI at 45° and 90° axis were higher than that at 0° and 135° axis, while MTFcut-off were lower. Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.

BIOM-07. DEVELOPING A CEREBROSPINAL FLUID-BASED BIOMARKER FOR MINIMAL RESIDUAL DISEASE AND RELAPSE IN PAEDIATRIC BRAIN TUMOURS USING METABOLOMIC METHODS

Abstract BACKGROUND Many paediatric brain tumours have poor outcomes due to relapse (50% in ependymoma and 30% in medulloblastoma) following treatment. Most of these occur within two years, suggesting persistent minimal residual disease (MRD) below the imaging detection threshold. Diagnosing MRD at the end-of-treatment or early relapse using a sensitive, minimally-invasive liquid biopsy could improve outcomes. Extracting metabolites arising from aberrant cancer metabolism, from cerebrospinal fluid (CSF) is promising because of the proximity of tumour to CSF. METHODS Liquid chromatography coupled with tandem high-resolution mass spectrometry (LC-MS/MS) using 25µl CSF extracted with 75µl methanol was shown to differentiate malignant paediatric brain tumours (n=47;day 14 samples) from controls (n=49). RESULTS Ependymomas (n=33) differed from medulloblastomas (n=14). Eighteen metabolites were identified as differentially abundant between tumours and controls with 14 metabolites being increased in abundance in tumours. These included amino acids and derivatives (n=8), metabolites in one carbon metabolism (n=1), carnitine cycle (n=2), aerobic glycolysis (n=2), purine catabolism (n=2), ascorbate degradation (n=1) and creatinine synthesis (n=2). From those, betaine/creatinine ratio gave an area under the curve (AUC) of 0.96 (excellent) in receiver operating curve analysis. Using a cut-off ratio of 0.1775 for discriminating brain tumours from controls, had sensitivity and specificity of 92% and 89%. Medulloblastomas were largely similar to ependymomas; nevertheless, three metabolites could discriminate between them, and met the criteria of corrected p&amp;lt;0.05. A ratio of glutarate semialdehyde/malic acid had AUC of 0.85 (good). With a cut-off ratio of 0.0422, the sensitivity and specificity were 79% and 82%. CONCLUSION This is the first CSF-based metabolomics study in ependymoma and third in medulloblastoma. Ratios of CSF metabolites can be used as biomarkers to detect brain tumours sensitively and specifically. This work will further be developed into a liquid biopsy test for the detection of MRD and early tumour recurrence.

Prevalence of anti-HLA antibodies in COVID-19 convalescent plasma donors: an Indian experience

BackgroundCOVID-19 convalescent plasma is one of the experimental therapies used widely in moderately sick COVID-19 patients. However, there are a few risks involved in plasma transfusion; notably, transfusion-related acute lung injury (TRALI) caused by antibodies against human leukocyte antigens (HLA). This study was designed to assess the prevalence of anti-HLA antibodies in convalescent plasma donors using the single antigen bead method. Study design and methodsThis was a hospital-based observational study of consecutive plasma donors. A total of 252 samples were screened for anti-HLA Class I and Class II antibodies using the microbead assay with the identification of anti-HLA Ab in positive samples being performed using a single antigen bead assay. Luminex-based normalized background cutoff ratios of 10.8 for Class I and 6.9 for Class II and mean fluorescence intensity cutoffs of 2500 for Class I and 1500 for Class II were used for screening and the single bead assay, respectively. ResultsOf 252 screened samples, 28 (11.1 %) were positive for Class I, Class II or both Class I and Class II anti-HLA antibodies in donors with no history of a previous immunizing event. Moreover, 20/252 (7.9%) donors without any history of prior immunization had specific anti-HLA antibodies of Class I or Class II or both by the single bead assay. ConclusionsThe high prevalence of anti-HLA antibodies in our cohort of donors raises an urgent and immediate need for anti-HLA antibody screening in all convalescent plasma donors for safe therapy of COVID-19 patients.

Integrated management of abatement technology investment and resource extraction

As the need for increased renewable energy generation to meet climate goals grows, so does the demand for critical minerals in the industrial sector. This raises concerns about the availability of supply and the reliability of investment in critical minerals. Based on this, the study proposes an analytical framework for the integrated management of mineral extraction and renewable energy investments. Different from the previous strategy of separate management, this study has established an integrated model that utilizes new energy technology as the downstream application of emission reduction technology. It also utilizes copper, zinc, aluminum, rare earth elements, and other materials as the upstream raw material supply. In terms of minimizing costs, the entire supply chain process is optimized to achieve an empirical case. In addition, considering the significant uncertainty in the process of reducing emissions from new energy technologies, this study also incorporated a forward control stochastic programming method to model and solve it. We obtained confidence intervals for optimal technological investment paths and metal mining paths under various scenarios. Our findings indicate that: (1) Biomass, as a renewable energy technology with the lowest resource demand, should be prioritized for development. However, there is significant uncertainty surrounding the installed capacity of photovoltaics. (2) Copper ore reserves have little impact on the development of renewable energy technologies, while zinc ore and aluminum ore have a greater impact on wind energy and photovoltaics, respectively. (3) By optimizing the cut-off ratio of raw ore under a specific amount of ore storage, we can ensure the availability of materials needed for downstream energy technology.

Screening the General Population for Non-Alcoholic Fatty Liver Disease: Model Development and Validation

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing worldwide. Screening the general population for this may help to select appropriate diagnostic and preventive measures before disease progression. We aimed to develop a screening method to identify patients with NAFLD in the general population. We analyzed cross-sectional data from a large Japanese study of NAFLD. Principal component analysis was used to analyze the data. Candidate predictors were patients' demographic, clinical, and laboratory characteristics. The resulting model was externally validated using three data sets from different populations. Of 15,464 (54.5% men) included patients, 2,741 (17.7%) had NAFLD as determined by ultrasonography. An index was calculated as the arithmetic mean of the scaled body mass index and serum triglyceride levels for both men and women. The area under the receiver operating characteristic curve, sensitivity, specificity, and false positive rate were 0.875, 0.824, 0.770, and 17.6%, respectively. The mean index values were significantly different between the patients with and without non-alcoholic fatty liver disease (p <0.001). The odds ratio of the index cutoff was 15.6 (95% confidence interval [CI]:14.05, 17.39). The model yielded areas under the curve of 0.828, 0.851, and 0.836 for a Chinese (N = 2,319), an Iranian (N = 2,160), and a Brazilian (N = 45,029) data set, respectively. The proposed composite index demonstrated high performance and generalizability, suggesting its potential use as a screening tool for NAFLD in the general population.

Development of a Time-Gated Epithermal Neutron Spectrometer for Resonance Absorption Measurements Driven by a High-Intensity Laser

The advance of laser-driven neutron sources (LDNSs) has enabled neutron resonance spectroscopy to be performed with a single shot of a laser. In this study, we describe a detection system of epithermal (∼eV) neutrons especially designed for neutron resonance spectroscopy. A time-gated photomultiplier tube (PMT) with a high cut-off ratio was introduced for epithermal neutron detection in a high-power laser experiment at the Institute of Laser Engineering, Osaka University. We successfully reduced the PMT response to the intense hard X-ray generated as a result of the interaction between laser light and the target material. A time-gated circuit was designed to turn off the response of the PMT during the laser pulse and resume recording the signal when neutrons arrive. The time-gated PMT was coupled with a 6Li glass scintillator, serving as a time-of-flight (TOF) detector to measure the neutron resonance absorption values of 182W and 109Ag in a laser-driven epithermal neutron generation experiment. The neutron resonance peaks at 4.15 eV of 182W and 5.19 eV of 109Ag were detected after a single pulse of laser at a distance of 1.07 m.