Controlling Inputter Variability in Vignette Studies Assessing Web-Based Symptom Checkers: Evaluation of Current Practice and Recommendations for Isolated Accuracy Metrics.

BACKGROUND: The rapid growth of web-based symptom checkers (SCs) is not matched by advances in quality assurance. Currently, there are no widely accepted criteria assessing SCs' performance. Vignette studies are widely used to evaluate SCs, measuring the accuracy of outcome. Accuracy behaves as a composite metric as it is affected by a number of individual SC- and tester-dependent factors. In contrast to clinical studies, vignette studies have a small number of testers. Hence, measuring accuracy alone in vignette studies may not provide a reliable assessment of performance due to tester variability. OBJECTIVE: This study aims to investigate the impact of tester variability on the accuracy of outcome of SCs, using clinical vignettes. It further aims to investigate the feasibility of measuring isolated aspects of performance. METHODS: Healthily's SC was assessed using 114 vignettes by 3 groups of 3 testers who processed vignettes with different instructions: free interpretation of vignettes (free testers), specified chief complaints (partially free testers), and specified chief complaints with strict instruction for answering additional symptoms (restricted testers). κ statistics were calculated to assess agreement of top outcome condition and recommended triage. Crude and adjusted accuracy was measured against a gold standard. Adjusted accuracy was calculated using only results of consultations identical to the vignette, following a review and selection process. A feasibility study for assessing symptom comprehension of SCs was performed using different variations of 51 chief complaints across 3 SCs. RESULTS: Intertester agreement of most likely condition and triage was, respectively, 0.49 and 0.51 for the free tester group, 0.66 and 0.66 for the partially free group, and 0.72 and 0.71 for the restricted group. For the restricted group, accuracy ranged from 43.9% to 57% for individual testers, averaging 50.6% (SD 5.35%). Adjusted accuracy was 56.1%. Assessing symptom comprehension was feasible for all 3 SCs. Comprehension scores ranged from 52.9% and 68%. CONCLUSIONS: We demonstrated that by improving standardization of the vignette testing process, there is a significant improvement in the agreement of outcome between testers. However, significant variability remained due to uncontrollable tester-dependent factors, reflected by varying outcome accuracy. Tester-dependent factors, combined with a small number of testers, limit the reliability and generalizability of outcome accuracy when used as a composite measure in vignette studies. Measuring and reporting different aspects of SC performance in isolation provides a more reliable assessment of SC performance. We developed an adjusted accuracy measure using a review and selection process to assess data algorithm quality. In addition, we demonstrated that symptom comprehension with different input methods can be feasibly compared. Future studies reporting accuracy need to apply vignette testing standardization and isolated metrics.

Metagenome analyses of microbial population in geotextile fabrics used in permeable reactor barriers for toluene biodegradation.

Toluene is one of the hydrocarbons that contaminate soil and groundwater, and has a high cost to remediate, which makes it an environmental pollutant of concern. This study aimed to find bacterial distribution from nonwoven geotextile (GT) fabric specimens in a pilot-scale permeable reactive barrier (PRB). Upon 167 days of incubation with the addition of toluene, the microbial community on the GT surfaces (n = 12) was investigated by the 16S rRNA metagenome sequencing approach. According to taxonomic classification, the Proteobacteria phylum dominated the metagenomes of all the geotextile samples (80-90%). Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway database search of the toluene degradation mechanism revealed the susceptible toluene-degrading species. For the toluene-to-benzoate degradation, the Cupriavidus genus, particularly C. gilardii, C. metallidurans, and C. taiwanensis, are likely to be functional. In addition to these species, the Novosphingobium genus was abundantly localized in the GTs, in particular Novosphingobium sp. ABRDHK2. The results suggested the biodegradation potential of these species in toluene remediation. Overall, this work sheds light on the variety of microorganisms found in the geotextile fabrics used in PRBs and the species involved in the biodegradation of toluene from several sources, including soil, sediment, and groundwater. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03460-y.

Protective effect of vanillic acid in hydrogen peroxide-induced oxidative stress in D.Mel-2 cell line.

The overproduction of reactive oxygen species (ROS) causes oxidative stress, such as Hydrogen peroxide (H2O2). Acute oxidative stress is one of the main reasons for cell death. In this study, the antioxidant properties of vanillic acid- a polyphenolic compound was evaluated. Therefore, this study aims to check the effectiveness of vanillic acid in H2O2-induced oxidative stress in D. Mel-2 cell line. The efficacy was determined by biochemical tests to check the ROS production. The cytotoxicity of H2O2 and vanillic acid was checked by MTT assay. The DNA fragmentation was visualized by gel electrophoresis. Protein biomarkers of oxidative stress were analyzed by western blotting. The results depict a promising antioxidant effect of vanillic acid. The IC50 value of vanillic acid and H2O2 was found 250 µg/ml and 125 µg/ml, respectively. The catalase activity, SOF, GPx, and PC was seen less in H2O2 treated group compared with the control and vanillic acid treated group. However, the TBRAS activity was hight in H2O2 treated group. The effect of H2O2 on DNA fragmentation was high as compared with vanillic acid-treated cells. The protein expression of Hsp70, IL-6 and iNOS was seen significant in a vanillic acid-treated group as compared with H2O2 treated group. These results reinforce that at low concentration, vanillic acid could be used as an antioxidant agent in the food and pharmaceutical industries.

Magnetic Mg-Fe/LDH Intercalated Activated Carbon Composites for Nitrate and Phosphate Removal from Wastewater: Insight into Behavior and Mechanisms.

This experimental work focused on the synthesis, characterization, and testing of a unique, magnetically separable, and eco-friendly adsorbent composite material for the advanced treatment and efficient removal of nitrate and phosphate pollutants from wastewater. The MgAl-augmented double-layered hydroxide (Mg-Fe/LDH) intercalated with sludge-based activated carbon (SBAC-MgFe) composites were characterized by FT-IR, XRD, BET, VSM, SEM, and TEM techniques, revealing homogeneous and efficient dispersion of MgFe/LDH within the activated carbon (AC) matrix, a highly mesoporous structure, and superparamagnetic characteristics. The initial solution pH, adsorbent dose, contact time, and temperature parameters were optimized in order to reach the best removal performance for both pollutants. The maximum adsorption capacities of phosphate and nitrate were found to be 110 and 54.5 mg/g, respectively. The competition between phosphate and coexisting ions (Cl-, CO32-, and SO42-) was studied and found to be remarkably lower in comparison with the nitrate adsorption. The adsorption mechanisms were elucidated by kinetic, isotherm, thermodynamic modeling, and post-adsorption characterizations of the composite. Modeling and mechanistic studies demonstrated that physisorption processes such as electrostatic attraction and ion exchange mainly governed the nitrate and phosphate adsorption. The composite indicated an outstanding regeneration performance even after five sequences of adsorption/desorption cycles. The fabricated composite with magnetically separable characteristics can be used as a promising adsorbent for the removal of phosphate and nitrate pollutants from wastewater.

Comparative Adsorptive Removal of Phosphate and Nitrate from Wastewater Using Biochar-MgAl LDH Nanocomposites: Coexisting Anions Effect and Mechanistic Studies.

In this study, date-palm biochar MgAl-augmented double-layered hydroxide (biochar-MgAl-LDH) nanocomposite was synthesized, characterized, and used for enhancing the removal of phosphate and nitrate pollutants from wastewater. The biochar-MgAl-LDH had higher selectivity and adsorption affinity towards phosphate compared to nitrate. The adsorption kinetics of both anions were better explained by the pseudo-first-order model with a faster removal rate to attain equilibrium in a shorter time, especially at lower initial phosphate-nitrate concentration. The maximum monolayer adsorption capacities of phosphate and nitrate by the non-linear Langmuir model were 177.97 mg/g and 28.06 mg/g, respectively. The coexistence of anions (Cl-, SO42-, NO3-, CO32- and HCO3-) negligibly affected the removal of phosphate due to its stronger bond on the nano-composites, while the presence of Cl- and PO43- reduced the nitrate removal attributed to the ions' participation in the active adsorption sites on the surface of biochar-MgAl-LDH. The excellent adsorptive performance is the main synergetic influence of the MgAl-LDH incorporation into the biochar. The regeneration tests confirmed that the biochar-MgAl composite can be restored effortlessly and has the prospective to be reused after several subsequent adsorption-desorption cycles. The biochar-LDH further demonstrated capabilities for higher removal of phosphate and nitrate from real wastewater.