Correction of <Emphasis Type="Italic">B</Emphasis><Subscript>0</Subscript>-induced geometric distortion variations in prospective motion correction for 7T MRI

Objective

Prospective motion correction can effectively fix the imaging volume of interest. For large motion, this can lead to relative motion of coil sensitivities, distortions associated with imaging gradients and B ₀ field variations. This work accounts for the B ₀ field change due to subject movement, and proposes a method for correcting tissue magnetic susceptibility-related distortion in prospective motion correction.

Materials and methods

The B ₀ field shifts at the different head orientations were characterized. A volunteer performed large motion with prospective motion correction enabled. The acquired data were divided into multiple groups according to the object positions. The correction of B ₀-related distortion was applied to each group of data individually via augmented sensitivity encoding with additionally integrated gradient nonlinearity correction.

Results

The relative motion of the gradients, B ₀ field and coil sensitivities in prospective motion correction results in residual spatial distortion, blurring, and coil artifacts. These errors can be mitigated by the proposed method. Moreover, iterative conjugate gradient optimization with regularization provided superior results with smaller RMSE in comparison to standard conjugate gradient.

Conclusion

The combined correction of B ₀-related distortion and gradient nonlinearity leads to a reduction of residual motion artifacts in prospective motion correction data.

     

Gluten‐free bakery and pasta products: prevalence and quality improvement

An increasing demand of gluten‐free (GF) products is caused by a growing number of diagnosed coeliacs and a consumption trend to eliminate allergenic proteins from diet. Driven by the rapidly growing market, comprehensive understanding of GF products is necessary. The purpose of this review was to concisely present an overview of various approaches to improve physicochemical and sensory qualities of GF bread, cake/muffin and pasta/noodle products. Some novel techniques used in GF products were discussed in this review. These techniques included the use of different alternative flours (including GF cereals, pseudo‐cereals, legume flours, fruit and vegetable powders and seafood powders), functional ingredients (including hydrocolloids and gums, emulsifiers, proteins and dietary fibres) and optimal processing (pretreated flour, infrared–microwave combination baking and extrusion cooking). Some recent novel technologies including transgenesis, enzymolysis and fermentation that have been used on GF products were also discussed.     

Low-sodium roasted peanuts: effects of salt mixtures (NaCl,KCl and glycine) on consumer perception and purchase intent

The effects of ten treatment combinations of two salts (NaCl, KCl) and glycine were evaluated on low-sodium roasted peanuts. Consumers’ (N = 330, recruited from college campus) liking, emotions, perceived saltiness and bitterness intensity, satisfaction and purchase intent (PI) of peanuts were measured following a balanced incomplete block design (t = 10, k = 3, r = 9, b = 30, λ = 2, e₂ = 0.74). Emotions and PI were evaluated both before and after presenting a low-sodium health benefit message. Sodium content of peanuts was reduced from 140 mg Na/50 g peanuts to 41.67 mg Na/50 g without significantly affecting liking scores and with positive PI over 60%. In general, high bitterness and low saltiness intensity ratings negatively affected liking and satisfaction. Consumers expressed less satisfaction when perceived saltiness intensity was ‘Not Enough’ than when ‘Too Much.’ Based on optimisation analysis, any formulation within the range of 59-100/0-40/0-12.5% NaCl/KCl/Gly- representing a potential 37% sodium reduction past minimum ‘low sodium’ requirements- will yield an acceptable product.     

A Novel, Low Temperature Synthesis Method of Dimethyl Ether Over Cu–Zn Catalyst Based on Self-Catalysis Effect of Methanol

A new DME synthesis route from syngas at a relatively low temperature (443 K) has been developed for the first time by the combination of a conventional DME synthesis catalyst (Cu/ZnO:HZSM-5 catalyst) with methanol as a catalytic solvent. The addition of methanol to the reaction system is the key to the success of DME synthesis at this temperature. Indeed, a CO conversion of 29 and 43% with a DME selectivity of 69 and 68% were achieved at 443 or 453 K, respectively, and 4 MPa, when methanol was used as a catalytic solvent. Importantly, no other by-products including methanol and hydrocarbons were observed in the DME product attained, suggesting no significant subsequent purification stages. Assuming no scale up problems, this process potentially provides a high purity of DME with less energy consumption, and so offers an opportunity for the economically viable future sustainable production of DME.     

Simulation of Lumbar Spinal Stenosis Using the Finite Element Method

Lumbar spine stenosis (LSS) is a narrowing of the spinal canal that results in pressure on the spinal nerves. This orthopedic disorder can cause severe pain and dysfunction. LSS is a common disabling problem amongst elderly people. In this paper, we developed a finite element model (FEM) to study the forces and the von Mises stress acting on the spine when people bend down. An artificial lumbar spine (L3) was generated from CT data by using the FEM, which is a powerful tool to study biomechanics. The proposed model is able to predict the effect of forces which apply to the lumbar spine. In addition, FEM allows us to investigate the tests into the lumbar spine instead of applying the tests to the real spine in humans. The proposed model is highly accurate and provides precise information about the lumbar spine (L3). We investigate the behavior of humans in daily life which effects to the lumbar spine in a normal person and a patient with LSS. The computational results revealed high displacement levels around the spinal canal and lower displacement levels in the spinal body when bending down. The total displacement of the axial load in a normal person was higher when compared with patients with LSS. Higher degree bends resulted in a lower total displacement when compared with lower degree bends, while the von Mises stress decreased as the bending degree increased.     

Optimisation of wheat flour‐based sponge cake formulation containing tapioca starch and xanthan gum

The optimum formulation for wheat flour (WF)‐based sponge cakes containing tapioca starch (TS) and xanthan gum (Xan) was determined using the central composite design with two factors and response surface methodology (RSM). Effects of partial substitution of TS (5–15%) for WF in a 20% total flour blend and Xan (0.1–0.3%) on specific volume, parameters of texture profile analysis and sensory liking scores of baked sponge cakes were investigated. A second‐order polynomial response surface was used to explain the influence of TS and Xan on the dependent variables. Coefficients of determination (R² ≥ 0.75) of the response variables and significant regression models were used for RSM optimisation. Based on the RSM contour plots, the cake formulation containing 16% butter with desired physical properties (maximum specific volume; minimum hardness, gumminess and chewiness) and sensory quality (maximum overall liking) was found to be 11.09–11.88% TS and 0.10–0.11% Xan.     

Experimental Investigation and Optimization of Micro-EDMing Process for Silicon Substrates

Microelectrical discharge machining of n-type monocrystalline silicon is investigated in this study through a microgrooving process. The pulse duration, pulse frequency, spark current, and gap voltage are varied in the experiments. The groove geometries and roughness are measured together with the material removal rate and electrode wear ratio. The results have shown that a large and deep groove can be made at high machining rate when a high spark energy condition is applied. This can, however, increase the electrode wear ratio as a consequence, making the process inefficient. A multiresponse optimization, using Grey relational analysis, has been applied. The optimum cut result has shown that good cut quality, high material removal rate, and low electrode wear ratio are achievable from this study.