An Attempt to Estimate the Noises in Homeopathic Pathogenetic Trials by Employing the Jaccard Similarity Index and Noise Index

Background The critical task of researchers conducting double-blinded, randomized, placebo-controlled homeopathic pathogenetic trials is to segregate the signals from the noises. The noises are signs and symptoms due to factors other than the trial drug; signals are signs and symptoms due to the trial drug. Unfortunately, the existing tools (criteria for a causal association of symptoms only with the tested medicine, qualitative pathogenetic index, quantitative pathogenetic index, pathogenic index) have limitations in analyzing the symptoms of the placebo group as a comparator, resulting in inadequate segregation of the noises. Hence, the Jaccard similarity index and the Noise index are proposed for analyzing the symptoms of the placebo group as a comparator. Methods The Jaccard similarity index is the ratio of the number of common elements among the placebo and intervention groups to the aggregated number of elements in these groups. The Noise index is the ratio of common elements among the placebo and intervention group to the total elements of the intervention group. Homeopathic pathogenetic trials of Plumbum metallicum, Piper methysticum and Hepatitis C nosode were selected for experimenting with the computation of the Jaccard similarity index and the Noise index. Results Jaccard similarity index calculations show that 8% of Plumbum metallicum's elements, 10.7% of Piper methysticum's elements, and 19.3% of Hepatitis C nosode's elements were similar to the placebo group when elements of both the groups (intervention and placebo) were aggregated. Noise index calculations show that 10.7% of Plumbum metallicum's elements, 13.9% of Piper methysticum's elements and 25.7% of Hepatitis C nosode's elements were similar to those of the placebo group. Conclusion The Jaccard similarity index and the Noise index might be considered an additional approach for analyzing the symptoms of the placebo group as a comparator, resulting in better noise segregation in homeopathic pathogenetic trials.

Optimization of the exergy efficiency, exergy destruction, and engine noise index in an engine with two direct injectors using NSGA-II and artificial neural network

Direct Dual Fuel Stratification (DDFS) strategy is a novel Low Temperature Combustion (LTC) strategy that has comparable thermal efficiency to the Reactivity Controlled Compression Ignition (RCCI) strategy, while it offers more control over the combustion process and the rate of heat release. The DDFS strategy uses two direct injectors for the low- and high-reactivity fuels (gasoline and diesel) to benefit from the RCCI concept. In this study, the injection strategy of the injectors of a gasoline/diesel DDFS engine was optimized from the thermodynamic perspective to maximize exergy efficiency and minimize exergy destruction and an engine noise index. An artificial neural network was developed with 576 samples from a CFD code to predict the DDFS mode behavior, and the non-dominated sorting genetic algorithm (NSGA-II) was used to obtain the Pareto Front and the optimal solutions. Compared to the base case, the exergy efficiency of the optimal cases increased by up to 2%, exergy destruction and Peak Pressure Rise Rate (PPRR) reduced by about 2.3%, and 2 bar/deg, respectively, in the optimal solutions. NOX and soot emissions were reduced by 40% and 35%, respectively, in the best-case scenarios.

Image quality and radiologists’ subjective acceptance using model-based iterative and deep learning reconstructions as adjuncts to ultrahigh-resolution CT in low-dose contrast-enhanced abdominopelvic CT: phantom and clinical pilot studies

Purpose In contrast-enhanced abdominopelvic CT (CE-APCT) for oncologic follow-up, ultrahigh-resolution CT (UHRCT) may improve depiction of fine lesions and low-dose scans are desirable for minimizing the potential adverse effects by ionizing radiation. We compared image quality and radiologists’ acceptance of model-based iterative (MBIR) and deep learning (DLR) reconstructions of low-dose CE-APCT by UHRCT. Methods Using our high-resolution (matrix size: 1024) and low-dose (tube voltage 100 kV; noise index: 20–40 HU) protocol, we scanned phantoms to compare the modulation transfer function and noise power spectrum between MBIR and DLR and assessed findings in 36 consecutive patients who underwent CE-APCT (noise index: 35 HU; mean CTDIvol: 4.2 ± 1.6 mGy) by UHRCT. We used paired t-test to compare objective noise and contrast-to-noise ratio (CNR) and Wilcoxon signed-rank test to compare radiologists’ subjective acceptance regarding noise, image texture and appearance, and diagnostic confidence between MBIR and DLR using our routine protocol (matrix size: 512; tube voltage: 120 kV; noise index: 15 HU) for reference. Results Phantom studies demonstrated higher spatial resolution and lower low-frequency noise by DLR than MBIR at equal doses. Clinical studies indicated significantly worse objective noise, CNR, and subjective noise by DLR than MBIR, but other subjective characteristics were better (P < 0.001 for all). Compared with the routine protocol, subjective noise was similar or better by DLR, and other subjective characteristics were similar or worse by MBIR. Conclusion Image quality, except regarding noise characteristics, and acceptance by radiologists were better by DLR than MBIR in low-dose CE-APCT by UHRCT. Graphical abstract

A phantom study to optimise the automatic tube current modulation for chest CT in COVID-19

On March 11, 2020, the World Health Organization declared the coronavirus disease 2019 (COVID-19) pandemic. The expert organisations recommend more cautious use of thoracic computed tomography (CT), opting for low-dose protocols. We aimed at determining a threshold value of automatic tube current modulation noise index below which there is a chance to miss an onset of ground-glass opacities (GGO) in COVID-19. A team of radiologists and medical physicists performed 25 phantom CT studies using different automatic tube current modulation settings (SUREExposure3D technology). We then conducted a retrospective evaluation of the chest CT images from 22 patients with COVID-19 and calculated the density difference between the GGO and unaffected tissue. Finally, the results were matched to the phantom study results to determine the minimum noise index threshold value. The minimum density difference at the onset of COVID-19 was 252 HU (p < 0.001). This was found to correspond to the SUREExposure 3D noise index of 36. We established the noise index threshold of 36 for the Canon scanner without iterative reconstructions, allowing for a decrease in the dose-length product by 80%. The proposed protocol needs to be validated in a prospective study.

Assessment of Noise Pollution of Kolkata Metro Railway System and Its Impact on Urban Receptors A Case Study

An assessment of noise quality was conducted at underground and overground metro stations, within the metro rakes (AC and Non-AC) and at an institutional building near elevated metro corridor to assess the exposure of Kolkata Metro Railway System. The present study was conducted in different hours (peak and non-peak hour) for different types of rake (AC and Non-AC) movement. Different noise descriptors including A-weighted equivalent noise (Leq), statistical noise (L10,L50,L90), noise climate (NC), traffic noise index (TNI), two hour noise dose (%ND) and corresponding time-weighted average (TWA) were calculated under the purview of the present study. Pearson’s correlation was performed between all noise descriptors to investigate the relation between them. Scatter plot analysis was conducted between L10 and %ND. In case of all study duration, all noise descriptors mostly exceeded FTA prescribed noise standard, along with 2-hr TWA which exceeded the OSHA guidelines of 100 dB for both AC and Non-AC rakes. On the other hand, at underground and overground metro stations, within metro rakes (except at day peak hour within AC coach) and at school building, mean value of traffic noise index (TNI) exceeded 74 dB (A), the threshold of over criterion. The study results indicate that Non-AC rakes are more annoying than AC-rakes. In all the study units, Leq was influenced by L10, which originates from pressure honking. There is very strong relationship observed between L10 and % ND. This study proposes that noise barrier should be installed at underground and overground metro stations, along the stretches of overground metro track, within metro rakes for developing the acoustic quality of Kolkata Metro Railway System and the areas of its immediate vicinity.

Diagnostic Reference Level of Radiation Dose and Image Quality among Paediatric CT Examinations in A Tertiary Hospital in Malaysia

Pediatrics are more vulnerable to radiation and are prone to dose compared to adults, requiring more attention to computed tomography (CT) optimization. Hence, diagnostic reference levels (DRLs) have been implemented as part of optimization process in order to monitor CT dose and diagnostic quality. The noise index has recently been endorsed to be included as a part of CT optimization in the DRLs report. In this study, we have therefore set local DRLs for pediatric CT examination with a noise index as an indicator of image quality. One thousand one hundred and ninety-two (1192) paediatric patients undergoing CT brain, CT thorax and CT chest-abdomen-pelvis (CAP) examinations were analyzed retrospectively and categorized into four age groups; group 1 (0–1 year), group 2 (1–5 years), group 3 (5–10 years) and group 4 (10–15 years). For each group, data such as the volume-weighted CT dose index (CTDIvol), dose-length product (DLP) and the effective dose (E) were calculated and DRLs for each age group set at 50th percentile were determined. Both CT dose and image noise values between age groups have differed significantly with p-value < 0.05. The highest CTDIvol and DLP values in all age groups with the lowest noise index value reported in the 10–15 age group were found in CT brain examination. In conclusion, there was a significant variation in doses and noise intensity among children of different ages, and the need to change specific parameters to fit the clinical requirement.

HYGIENIC ASPECTS OF URBAN PLANNING ON THE AERODROME ENVIRONS

We considered some hygiene reasons of the 7th subzone of aerodrome environs of civil aviation airport. It has been established that there is no method to assess the acute risk to public health from exposure to noise. This makes it difficult to determine the spatial quantity of the 7th subzone of aerodrome environs rationale for noise. A differentiated approach to the zoning of the 7th subzone of aerodrome environs to ensure sanitary and epidemiological well-being of the population, as well as for the rational urban zoning is justified. Proposals for the division of the 7th subzone of aerodrome environs by the degree of noise impact are presented. We presented proposals for rationing aviation noise near airfields by day, night and daily noise index. The prospects of revision of the existing methodological approaches to establishing the size of aerodrome environs on the basis of risk are determined.