Brain-based classification of youth with anxiety disorders: transdiagnostic examinations within the ENIGMA-Anxiety database using machine learning

Neuroanatomical findings on youth anxiety disorders are notoriously difficult to replicate, small in effect size and have limited clinical relevance. These concerns have prompted a paradigm shift toward highly powered (that is, big data) individual-level inferences, which are data driven, transdiagnostic and neurobiologically informed. Here we built and validated supervised neuroanatomical machine learning models for individual-level inferences, using a case–control design and the largest known neuroimaging database on youth anxiety disorders: the ENIGMA-Anxiety Consortium (N = 3,343; age = 10–25 years; global sites = 32). Modest, yet robust, brain-based classifications were achieved for specific anxiety disorders (panic disorder), but also transdiagnostically for all anxiety disorders when patients were subgrouped according to their sex, medication status and symptom severity (area under the receiver operating characteristic curve, 0.59–0.63). Classifications were driven by neuroanatomical features (cortical thickness, cortical surface area and subcortical volumes) in fronto-striato-limbic and temporoparietal regions. This benchmark study within a large, heterogeneous and multisite sample of youth with anxiety disorders reveals that only modest classification performances can be realistically achieved with machine learning using neuroanatomical data.NWORubicon 019.201SG.022Advanced Behavioural Research MethodsHealth and Well-bein

Effects of operating conditions on degradable cushioning extrudate's cellular structure and the specific heat

Generally, single-used foam packaging is used by manufacturers to protect and preserve a wide array of food and industrial products. Expanded polystyrene (EPS) is used extensively in single-use packages due to its low density, thermal insulation, strength and low cost (Alliance of Foam Packaging Recyclers (AFPR), 1999). The objective of this study is to focus on the process variables (feed composition, die temperature and screw speed) affecting the cellular structure and the thermal properties of extrudates and to evaluate com/PVA extrudate as packaging material. The experimental results indicated that the cell size became smaller and uniform; moreover, the cell wall thickness became thinner with the increase in die temperature and screw speed. Moreover, increasing the PVA ratio ranged from 5% to 30% also made the cell sizes became smaller and uniform. The corn granules blended with 15% PVA (Treatment 26) have potential applications as thermal insulation for their high specific heat values. The formulation with 15% PVA (Treatment 26) had the highest specific heat. For all formulations, the specific heat increased linearly as the temperature increased. (c) 2004 Elsevier Ltd. All rights reserved

The effects of die shapes and additives on the physical and biodegradable properties of biodegradable cushioning extruded foams

In this study, efforts were focused on the effects of the operating parameters, i.e. die shapes (DS), PVA ratio (PR), additives (AT) on the physical and biodegradable properties of the corn/PVA extrudates. We also evaluated the extrudates as cushioning materials. The process variables were the operating, conditions, die shapes (O, infinity, A and O), PVA ratio (40%, 50%, 60%) and additives [sodium bicarbonate (NaHCO3), calcium carbonate (CaCO3) and calcium hydroxide (Ca(OH)(2))]. The experiment is a 4 x 3 x 3 factorial design. Samples of each treatment were collected and the physical, mechanical and chemical properties were measured and analysed using the PROC ANOVA and PROC CORR of the SAS 6.0 software package. The experimental results indicated that: (a) The change of die shapes (DS) had a significant effect on the longitudinal expansion, bulk density, compressibility and biodegradability properties of the extrudates; (b) the change of PVA ratio (PR) had a significant effect on the longitudinal expansion, bulk density and compressibility, but no effect on the biodegradability properties of the extrudates; and (c) the change of additives (AT) had a significant effect on the longitudinal expansion, bulk density and compressibility, but no effect on the spring index of the extrudates. Copyright (C) 2003 John Wiley Sons, Ltd

Effects of initial load levels and crosshead speed levels on viscoelastic properties of biodegradable loose fill extrudates

The viscoelastic properties of biodegradable loose fill extrudates can provide information at the structural level of the biodegradable cushioning materials used. The objective of this study was to test two theological models of linear viscoelastic theory (generalized Maxwell with three units in parallel, and Burgers) using the results of stress relaxation tests in biodegradable loose fill extrudates. The experiments were run at 105 degrees C with screw speed 500 rpm and die diameter 3.92 mm. The extrudates were then submitted to tests of stress relaxation in an equipment of mechanical measurements, Instron Universal Testing Machine (Model 4464). The deformation, imposed to the extrudate, was 1%, guaranteeing the permanency in the domain of the linear viscoelasticity. The models were fitted to experimental data (stress x time) by nonlinear regression. The generalized Maxwell model with three units in parallel and the Burgers model represented the relaxation curves of stress satisfactorily. The viscoelastic properties varied in a way that they were less dependent on the initial stress levels. (c) 2006 Elsevier Ltd. All rights reserved

Effects of composition levels on the cellular structure and the thermal properties of biodegradable cushioning extrudates

Response surface methodology (RSM) was used to analyze the effect of polyvinyl alcohol (PVA) and calcium carbonate (CaCO3) on the cellular structure and the thermal properties of a biodegradable cushioning extrudate. A central-composite design (CCD) was used to develop models for the objective responses. The experiments were run at 105degreesC with a feed rate of 27.8L/h, a screw speed of 500rpm and a die diameter of 3.92 mm. The responses were most affected by changes in polyvinyl alcohol (PVA) levels and to a lesser extent by calcium carbonate (CaCO3) levels. The objective of this study is to focus on the composition levels affecting the cellular structure (average pore size) and the thermal properties (specific heat capacity and thermal conductivity) of extruded foams and to evaluate the possibility of using compare extrudates as packaging and insulating materials. The experimental results indicated that: 1. The cell sizes become smaller and more uniform and the cell walls become thinner with the increase in the PVA ratio. Moreover, using the CaCO3 also made the cell sizes become smaller and more uniform. 2. For all the treatments, the specific heat increased linearly as the temperature increased. Several treatments have potential applications for thermal insulation because of their relatively high specific heat values and low thermal conductivity values

Effects of operating conditions on the cellular structure and the thermal properties of extruded foams made from corn

The characteristics of a corn extrudate generally appear similar to commercial plastic foam cushioning materials. If extruded foams from whole yellow dent corn are used for loose fill cushioning material, low cost will be realized. In addition, this extruded foam is biodegradable and might even be recoverable as animal feed or as an ethanol feedstock. It could also be spread on farm fields as a soil amendment. Extrusion technology has been applied in cornstarch processing for many years. Different categories of extruders have been developed to give various advantages and disadvantages as used for production. The low-moisture (low-cost) extruder cooker is a good choice for producing low cost expanded corn for packaging use. The objective of this study is to focus on the feed compositions and screw configurations affecting the cellular structure and the specific heat of extruded foams and to evaluate corn/PVA extrudates as packaging material. Experimental results indicated that: 1. The size of air cells became smaller and more uniform, and the air cell wall became thinner with the increase in screw pitch and screw speed. Moreover, using the food grade corn grits also made the size of cells smaller and more uniform. 2. Treatments 5 and 22 had the highest specific heats. For all treatments, the specific heat increased linearly as the temperature increased. 3. The extrudates from Treatments 5 and 22 have potential applications as thermal insulation applications for their high specific heat values

Physical, mechanical, biodegradable properties and energy absorption behavior of corn grit-polyvinyl alcohol cushioning extrudates

The focus of the study was on the effects of PVA ratio (PR), screw speed (SS) and die temperature (DT) on the physical, mechanical, biodegradable properties and energy absorption behavior of corn grit/PVA cushioning extrudates. The experimental results indicated that PR had a significant effect on the radial expansion ratio, bulk density, compressibility. spring index and biodegradable properties. SS had a significant effect on the radial expansion ratio, compressibility, spring index, biodegradable properties and the radial expansion ratio. DT had a most significant effect on the compressibility and spring index of the extrudates. Corn grit blended with 5% of PVA had the minimum total energy absorption (TEA) and energy absorption of each cycle (EAEC). All treatments of the extrudates had the maximum energy absorption at the crosshead speed 400 mm/min. The resultant extrudates were suitable for packaging applications especially cushioning materials. (c) 2004 Elsevier Ltd. All rights reserved

Composition optimization of extruded starch foams using response surface methodology

Response surface methodology (RSM) was used to analyse the effect of polyvinyl alcohol (PVA) and calcium carbonate (CaCO3) on the objective attributes (shipping bulk density, radial expansion ratio, compressibility and spring index) of a biodegradable cushioning extrudate. A rotatable central composite design (CCD) was used to develop models for the objective responses. The experiments were run at 105degreesC with a feed rate of 27.8 l/h, screw speed 500 r.p.m. and die diameter 3.92 mm. Responses were most affected by changes in polyvinyl alcohol (PVA) levels and to a lesser extent by calcium carbonate (CaCO3) levels. Individual contour plots of the different responses were overlaid, and regions meeting the optimum shipping bulk density of 6.00 kg/m(3). radial expansion ratio of 3.30, compressibility of 43.71 N, and spring index of 0.91 were identified at the PVA level of 20.23% and the CaCO3 level of 7.89%, respectively. Copyright (C) 2004 John Wiley Sons, Ltd

Effects of die shapes and additives on the physical and mechanical properties, and cellular structure of biodegradable cushioning extruded foams

Efforts are focused on the effects of operating parameters, i.e., die shapes (DS), PVA ratio (PR), and additives (AT), on the physical and mechanical properties of corn-PVA extrudates in this study. The cellular structure of biodegradable extruded foams are studied and the extrudates are evaluated as cushioning materials. The process variables are the operating conditions, DS (O, infinity, Delta, and 0), PR (40, 50, 60%), and AT (8%) (sodium bicarbonate (NaHCO3), calcium carbonate (CaCO3), calcium hydroxide (Ca(OH)(2))). The experimental setup is a 4 x 3 x 3 factorial design. Samples of each treatment are collected and the physical and mechanical properties are measured and analyzed using the PROC ANOVA and PROC CORR of the SAS 6.0 software package. Moreover, the cellular structures of the extrudates are observed by using a scanning electron microscope. The experimental results indicate that: (a) the change of DS has a significant effect on the longitudinal expansion, bulk density, and compressibility of the extrudates; (b) the change of PR has a significant effect on the longitudinal expansion, bulk density, and compressibility of the extrudates; (c) the change of AT has a significant effect on the longitudinal expansion, bulk density, and compressibility of the extrudates; (d) the most uniform cell is obtained with the O-shaped die, as compared with other die shapes. A moderate cell wall is obtained with the O-shaped die. The largest cell sizes are found in PVA 60% with CaCO3. However, the smallest cell sizes are found in PVA 60% with NaHCO3. Changing the types of additives from NaHCO3 to CaCO3, and CaCO3 to Ca(OH)(2) increases the cell size and cell wall thickness