Nevin Manimala

Phys Med Biol. 2021 Mar 25. doi: 10.1088/1361-6560/abf1fd. Online ahead of print.

ABSTRACT

A Machine Learning approach to the problem of calculating the proton paths inside a scanned object in proton Computed Tomography is presented. The method is developed in order to mitigate the loss in both spatial resolution and quantitative integrity of the reconstructed images caused by multiple Coulomb scattering of protons traversing the matter. Two Machine Learning models were used: a forward neural network and the XGBoost method. A heuristic approach, based on track averaging was also implemented in order to evaluate the accuracy limits on track calculation, imposed by the statistical nature of the scattering. Synthetic data from anthropomorphic voxelized phantoms, generated by the Monte Carlo Geant4 code, were utilised to train the models and evaluate their accuracy, in comparison to a widely used analytical method that is based on likelihood maximization and Fermi-Eyges scattering model. Both neural network and XGBoost model were found to perform very close or at the accuracy limit, further improving the accuracy of the analytical method (by 12% in the typical case of 200MeV protons on 20 cm of water object), especially for protons scattered at large angles. Inclusion of the material information along the path in terms of radiation length did not show improvement in accuracy, for the phantoms simulated in the study. A neural network was also constructed to predict the error in path calculation, thus enabling a criterion to filter out proton events that may have a negative effect on the quality of the reconstructed image. By parametrizing a large set of synthetic data, the Machine Learning models were proved capable to bring – in an indirect and time efficient way – the accuracy of the Monte Carlo method into the problem of proton tracking.

PMID:33765674 | DOI:10.1088/1361-6560/abf1fd

Phys Med Biol. 2021 Mar 25. doi: 10.1088/1361-6560/abf1ff. Online ahead of print.

ABSTRACT

Ion CT promises to mitigate range uncertainties inherent in the conversion of x-ray Hounseld units into ion relative stopping power (RSP) for ion beam therapy treatment planning. To improve accuracy and spatial resolution of ion CT by accounting for statistical multiple Coulomb scattering defection of the ion trajectories from a straight line path (SLP), the most likely path (MLP) and the cubic spline path (CSP) have been proposed. In this work, we use FLUKA Monte Carlo simulations to investigate the impact of these path estimates in iterative tomographic reconstruction algorithms for proton, helium and carbon ions. To this end the ordered subset simultaneous algebraic reconstruction technique was used and coupled with a total variation superiorization (TVS). We evaluate the image quality and dose calculation accuracy in proton therapy treatment planning of cranial patient anatomies. CSP and MLP generally yielded nearly equal image quality with an average RSP relative error improvement over the SLP of 0.6%, 0.3% and 0.3% for proton, helium and carbon ion CT, respectively. Bone and low density materials have been identied as regions of largest enhancement in RSP accuracy. Nevertheless, only minor dierences in dose calculation results were observed between the different models and relative range errors of better than 0.5% were obtained in all cases. Largest improvements were found for proton CT in complex scenarios with strong heterogeneities along the beam path. The additional TVS had substantially reduced image noise, resulting in improved image quality in particular for soft tissue regions. Employing the CSP and MLP for iterative ion CT reconstructions enabled improved image quality over the SLP even in realistic and heterogeneous patient anatomy. However, only limited benet in dose calculation accuracy was obtained even though an ideal detector system was simulated.

PMID:33765672 | DOI:10.1088/1361-6560/abf1ff

J Breath Res. 2021 Mar 25. doi: 10.1088/1752-7163/abf209. Online ahead of print.

ABSTRACT

The oral malodor reduction efficacy of dentifrices containing stannous fluoride (SnF2) or zinc plus arginine (Zn/Arg) was evaluated using a halimeter to measure volatile sulfur compounds (VSCs) in two randomized, controlled, single-blind, cross-over pilot clinical trials. Study 1 (N=16) had five 1100 ppm F dentifrices and five treatment periods: Negative Control (NC): 0.243% sodium fluoride (NaF); SnF2 A: 0.454% SnF2+pyrophosphate; SnF2 B: 0.454% SnF2+sodium hexametaphosphate; SnF2 C: 0.454% SnF2+citrate; and SnF2 D: experimental 0.454% SnF2 with increased bioavailable Sn. Study 2 (N=16) had four 1450 ppm F dentifrices and four treatment periods: NC: 0.1% NaF+0.76% sodium monofluorophosphate; Zn/Arg: NaF+zinc+arginine; SnF2 E: 0.454% SnF2+0.078% NaF +sodium hexametaphosphate; SnF2 F: 0.454% SnF2+0.078% NaF+citrate. Each period took 96 hours; Baseline (Day 0) morning to Day 4 morning. Subjects brushed 2x/day with the treatment dentifrice. VSC levels were measured in the morning, prior to morning brushing, on Days 0 and 4. Changes in VSC scores from Day 0 to Day 4 were assessed using a mixed-model analysis of covariance for cross-over studies. In Study 1, SnF2 dentifrices B, C and D showed statistically significant reductions (31.3%, 24.8%, 34%, respectively) in VSC scores versus baseline (p <0.001); the benefits of these treatments versus NC and SnF2 dentifrice A were statistically significant (p ≤0.001). In Study 2, SnF2 dentifrices E and F showed statistically significant reductions (31.2%, 22.1%, respectively) in VSC scores versus baseline (p ≤0.010); the benefits of these treatments versus NC and the Zn/Arg dentifrice were statistically significant (p< 0.035). The Zn/Arg dentifrice showed a significant increase of 35.2% (p<0.001) in VSC scores versus baseline. These studies demonstrated that SnF2 dentifrices can provide significant oral malodor reductions, but the benefit is formulation dependent. The presence of SnF2 is not sufficient to ensure efficacy. The Zn/Arg dentifrice increased VSC levels, indicating greater malodor.

PMID:33765667 | DOI:10.1088/1752-7163/abf209

Behav Res Ther. 2021 Feb 20;140:103832. doi: 10.1016/j.brat.2021.103832. Online ahead of print.

ABSTRACT

It has been suggested that mental habits may underpin a heightened disposition to engage in rumination in response to negative mood. The aim of the current study was to assess the role of habit in the dynamic interplay between affect and ruminative thinking in the flow of daily life experiences. Using mobile ecological momentary assessment, 97 participants recorded affect and rumination ten times daily over six days, after completing measures of trait ruminative brooding and habitual characteristics of negative thinking (e.g. automaticity, lack of conscious awareness, intent and control). Momentary fluctuations in negative (increased) and positive (decreased) affect was prospectively associated with greater rumination-levels at the next sampling occasion. The degree to which affect triggered a subsequent ruminative response was moderated by habitual characteristics of negative thinking in a theoretically consistent way. Stronger temporal pairing of negative affect and rumination was also associated with greater emotional inertia but less carry-over of rumination from one moment to the next. Depression vulnerability may be in the form of rumination being habitually triggered in response to momentary fluctuations in affect, with deleterious effect on mood. The findings may have clinical implications, as targeting the habitual nature of rumination might help reduce depression vulnerability.

PMID:33765651 | DOI:10.1016/j.brat.2021.103832

Clin Imaging. 2021 Feb 24;78:51-59. doi: 10.1016/j.clinimag.2021.02.030. Online ahead of print.

ABSTRACT

OBJECTIVES: To determine the differential diagnosis of dermal and sub-dermal soft tissue masses which do not extend to the deep fascia that are referred to a specialist musculoskeletal oncology service.

MATERIALS AND METHODS: Review of all patients referred to a specialist musculoskeletal oncology service over a 13-month period with a dermal or sub-dermal soft tissue mass which did not extend to the deep fascia based on MRI appearances. Data collected included age, gender, site and maximal lesion size, and final histological diagnosis for biopsied and/or excised lesions.

RESULTS: 56 patients were included, 21 (37.5%) males and 35 (62.5%) females with mean age 49.75 years (range 5-86 years). 3 patients had 2 lesions making a total of 59 lesions, 11 (18.6%) dermal and 48 (81.4%) sub-dermal. Histological diagnosis was available in 44 (74.6%) cases, of which 11 (25%) were non-neoplastic, 23 (52.3%) were benign neoplasms, and 10 (22.7%) were malignant neoplasms. Although older age at presentation and greater mean maximal tumour dimension were seen with malignant lesions, these did not reach statistical significance (p = 0.154 and 0.102 respectively). There was also no relationship between skin involvement from sub-dermal lesions and malignancy, but 5 of 6 dermal lesions which showed an exophytic growth pattern were malignant.

CONCLUSIONS: The differential diagnosis of dermal and sub-dermal lesions which do not reach the deep fascia is wide with a malignant lesion being the cause in almost one-quarter of cases.

PMID:33765643 | DOI:10.1016/j.clinimag.2021.02.030

Int J Food Microbiol. 2021 Mar 16;346:109160. doi: 10.1016/j.ijfoodmicro.2021.109160. Online ahead of print.

ABSTRACT

The resistance of Salmonella to the harsh conditions occurring in shelf-stable dry fermented sausages (DFS) poses a food safety challenge for producers. The present study aimed to model the behaviour of Salmonella in acid (with starter culture) and low-acid (without starter culture) DFS as a function of a_w and storage temperature in order to build a decision supporting tool supporting the design of a corrective storage strategy to enhance the safety of DFS. Salmonella spp. were inoculated in the raw meat batter at ca. 6 Log cfu/g with a cocktail of 3 strains (CTC1003, CTC1022 and CTC1754) just before mixing with the other ingredients and additives. After stuffing, sausages were fermented and ripened following industrial processing conditions. Different drying-times were applied to obtain three batches with different a_w (0.88, 0.90 and 0.93). Afterwards, DFS were stored at 4, 8, 15 and 25 °C for a maximum of three months and Salmonella spp. were periodically enumerated. The Weibull model was fitted to Log counts data to estimate inactivation kinetic parameters. The impact of temperature and a_w on the primary inactivation parameters was evaluated using a polynomial equation. The results of the challenge tests showed that Salmonella spp. levels decreased during storage at all the assayed conditions, from 0.8 Log (in low-acid DFS at 4 °C) up to 6.5 Log (in acid DFS at 25 °C). The effect of both a_w and temperature was statistically significant. Delta (δ) parameter decreased by decreasing a_w and increasing temperature, while the shape (p) parameter ranged from above 1 (concave) at 10 °C to below 1 at 25 °C (convex). A common secondary model for the p parameter was obtained for each type of DFS, acid and low-acid, indicating that acidification during the production of DFS affected the time for the first Log reduction (δ) during the subsequent storage, but not the overall shape (p parameter) of the inactivation. The developed models covered representative of real conditions, such as Salmonella contamination in the raw materials and its adaptation to the harsh processing conditions. The good predictive performance shown when applying the models to independent data (i.e. up to 80% of the predictions within the ‘Acceptable Simulation Zone’ for acid sausages) makes them a suitable and reliable risk management tool to support manufacturers to assess and design a lethality treatment (i.e. corrective storage) to enhance the Salmonella inactivation in the product before DFS are released to the market.

PMID:33765642 | DOI:10.1016/j.ijfoodmicro.2021.109160

Psychoneuroendocrinology. 2021 Mar 17;128:105203. doi: 10.1016/j.psyneuen.2021.105203. Online ahead of print.

ABSTRACT

Best practice standards for measuring analyte levels in saliva recommend that all biospecimens be tested in replicate with mean concentrations used in statistical analyses. This approach prioritizes minimizing laboratory-based measurement error but, in the process, expends considerable resources. We explore the possibility that, due to advances in salivary assay precision, the contribution of laboratory-based measurement error in salivary analyte data is very small relative to more important and meaningful variability in analyte levels across biological replicates (i.e., between different specimens). To evaluate this possibility, we examine the utility of the repeatability intra-class correlation (rICC) as an additional index of salivary analyte data precision. Using randomly selected subsamples (Ns=200 and 60) of salivary analyte data collected as part of a larger epidemiologic study, we compute the rICCs for seven commonly assayed salivary measures in biobehavioral research – cortisol, alpha-amylase, c-reactive protein, interlekin-6, uric acid, secretory immunoglobulin A, and testosterone. We assess the sensitivity of rICC estimates to assay type and the unique distributions of the underlying analyte data. We also use simulations to examine the bias, precision, and coverage probability of rICC estimates calculated for small to large sample sizes. For each analyte, the rICCs revealed that less than 5% of variation in analyte levels was attributable to laboratory-based measurement error. rICC estimates were similar across all analytes despite differences in analyte levels, average intra-assay coefficients of variation, and in the distributional properties of the data. Guidelines for calculating rICC are provided to enable investigators and laboratory staff to apply this metric and more accurately quantify, and communicate, the magnitude of laboratory-based measurement error in their data. By helping investigators scale measurement error relative to more scientifically meaningful variability between biological replicates, the application of the rICC has the potential to influence research strategies and tactics such that resources (e.g., finances, effort, number/volume of biospecimens) are allocated more efficiently and effectively.

PMID:33765641 | DOI:10.1016/j.psyneuen.2021.105203

Ecotoxicol Environ Saf. 2021 Mar 22;215:112055. doi: 10.1016/j.ecoenv.2021.112055. Online ahead of print.

ABSTRACT

The present manuscript elucidated the ameliorative potential of nano-maghemite (FeNPs) against the hazardous effects of fluoride toxicity in the sensitive rice cultivar, IR-64. Fluoride pollution triggered bioaccumulation in root, shoot and spikelets which inhibited reproduction, agronomic development and mineral uptake. Suppressed activity of enzymatic antioxidants and excessive cobalt translocation manifested severe ROS-induced oxidative injuries. Seedling priming with FeNPs reduced fluoride bioaccumulation and promoted efficient uptake of macroelements and micronutrients like potassium, calcium, iron, zinc, copper, nickel, manganese, selenium and vanadium and reduced the translocation of cobalt in mature seedlings during stress. This altogether triggered growth and activated the enzymes like SOD, CAT, APX and GPOX. High accumulation of non-enzymatic antioxidants like proline, anthocyanins, flavonoids, phenolics along with stimulated GSH synthesis (determined from high GR, GST and GPX activity) and glyoxalase activity enabled FeNP-pulsed plants to efficiently scavenge ROS, O₂^–, H₂O₂ and methylglyoxal, and mitigate oxidative injuries. The ROS production was also lowered due to suppressed NADPH oxidase activity. This ensured subsequent revitalization of Hill activity and the level of photosynthetic pigments. Due to reduced fluoride partitioning and improved nutritional sink, the grain and panicle development in FeNP-primed, stressed seedlings were more stimulated than even control sets. Overall, our findings supported by statistical modelling established the potential of iron-nanotechnology in promoting safe rice cultivation even in fluoride-polluted environments.

PMID:33765592 | DOI:10.1016/j.ecoenv.2021.112055

Biomed Pharmacother. 2021 Mar 22;138:111414. doi: 10.1016/j.biopha.2021.111414. Online ahead of print.

ABSTRACT

Benign prostatic hyperplasia (BPH) is a common condition in adult men. Especially in Europe, increasing attention has been focused on E. angustifolium extracts (EAEs), which are widely used for their positive effects on the symptoms of BPH, although human clinical trials are limited. The aim of this monocentric, randomized, double-blind, placebo-controlled clinical trial is to evaluate if a daily intake of hard, gastric-resistant capsules containing a chemically characterized EAE (500 mg) for 6 months may allow a significant improvement in symptoms in subjects with BPH. This study was conducted in 128 adult men, randomly assigned to receive either EAE food supplement (N = 70) or placebo (N = 58), who underwent four visits (baseline = t0, after 15 days = t1, after 2 months = t2 and after 6 months = t3) in an outpatient setting to evaluate post-void residual (PVR) and prostate volume (PV) by means of prostate ultrasound, prostate-specific antigen (PSA) and neutrofile/lymphocyte ratio (N/L), nocturia before the clinical visits and International Prostate Specific Score (IPSS) registered by the physicians. EAE food supplement induced a significant decrease in the PVR and consequently nocturia improving the quality of life as suggested by the decrease of IPSS. No subjects reported adverse effects related to oral intake of EAE food supplement. Moreover, EAE food supplement did not show hepatic or renal toxicity. In conclusion, EAE food supplements can be used in subjects with BPH, to improve their quality of life and general renal function.

PMID:33765581 | DOI:10.1016/j.biopha.2021.111414

J Affect Disord. 2021 Mar 9;287:15-18. doi: 10.1016/j.jad.2021.03.002. Online ahead of print.

ABSTRACT

BACKGROUND: Numerous studies on seasonality of birth for mood disorders and schizophrenia have been published but findings are inconsistent ¹. We aim to test the hypothesis of lack of seasonal birth differences in hospitalized Bipolar Disorder and Schizophrenia patients.

METHODS: 15969 inpatient records in UTHealth Harris County Psychiatric Center between 2012-2014 were enrolled (HSC-MS-14-0274). Patients birth months that were diagnosed as Schizophrenia (n=4178) and Bipolar Disorder (n=5303) according to the DSM IV Criteria were tabulated including admitting diagnosis. Texas Birth statistics between 1903-1997 were obtained as control group (n= 17096471).

RESULTS: There was no significant difference for winter births between schizophrenia patients and control group (P=0.738) and there was no significant difference for winter births between bipolar patients and control group either (P= 0.862). Mann Kendall Trend Analysis showed no significant trends of birth months for schizophrenia, bipolar and control groups.

LIMITATIONS: The study limitations include being a retrospective study, inability to control for environmental factors, and recruiting from a single location.

CONCLUSIONS: Our large sample showed no association between birth season or months with schizophrenia or bipolar disorder. Severe schizophrenia that requires admission may not be related with birth seasonality.

PMID:33765537 | DOI:10.1016/j.jad.2021.03.002