Form measurements of micro-holes

The form measurement and gauge repeatability and reproducibility (R&R) of a micro-hole using a coordinate measurement machine (CMM) with a combination of optical and contact sensors were conducted in this study. The micro-holes, about 160 µm in diameter and 0.9 mm in depth, were fabricated using the electrical discharge machining process for diesel fuel injectors. The shape and size of micro-holes are important for the desired spray pattern, fuel economy and exhaust emission of diesel engines. In this study, the setup of the measurement machine and the procedure to determine the contact points are presented. Five form characteristics, the cylindricity, diameter, roundness, straightness and taper, of the micro-hole are analyzed from measurement points. The gauge R&R test is conducted to determine the micro-hole form measurement capability and to calculate the tolerance specifications for each characteristic that the CMM is capable of measuring. An example to quantify the change in the shape of the micro-holes before and after the abrasive flow machining is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58130/2/mst7_11_045.pd

The effects of single bouts of moderate-intensity continuous exercise and high-intensity interval exercise on the modulations of inhibitory control, working memory, and long-term memory

Although existing literature has suggested facilitation on various aspects of cognitive function during the recovery period following a single bout of moderate-intensity continuous exercise (MICE), little is known regarding how to optimize the prescription of acute exercise for maximizing its transient benefits on cognition. High-intensity interval exercise (HIIE) is growing in popularity as a mode of exercise known for its effectiveness and efficiency toward improving multiple health outcomes. However, a limited understanding exists regarding the transient effects of HIIE on post-exercise cognition compared to MICE. Accordingly, the aim of this investigation was to compare the effect of acute HIIE and MICE on inhibitory control, working memory, and long-term memory. Using a within-participants design, event-related potentials (ERPs) and task performance were assessed while participants performed a free recall task, a modified flanker task, and a modified Sternberg task following 20 minutes of seated rest, MICE, and HIIE on three separate days in counterbalanced order. Following both MICE and HIIE, participants recalled more words in the free recall list and exhibited shorter reaction time during the flanker task relative to the rest condition. HIIE resulted in additional facilitation, as indexed by reduced reaction time interference scores during the flanker task and reduced overall reaction time during the Sternberg task relative to rest. Neuroelectric analysis indicated that MICE increased P3 amplitude compared to rest and HIIE, while HIIE decreased P3 latency relative to rest. CNV was unchanged following MICE compared to rest, while HIIE increased initial CNV amplitude relative to rest. These results suggest that both types of exercise may improve cognitive performance, with HIIE having additional benefits relative to MICE. To support inhibitory control and working memory operations, MICE and HIIE may exert differential influences on brain function, with MICE increasing attentional resource allocation and HIIE improving stimulus identification and cognitive processing speed. Taken together, the findings of the present investigation demonstrate transient facilitating effects on cognition following acute bouts of MICE and HIIT, and provide preliminary evidence to support HIIE as a promising alternative approach for enhancing cognitive performance

Quasi-Hermitian extended SSH models

We consider the quasi Hermitian limit of a non-Hermitian extended Su Schrieffer Heeger model, in which the hopping amplitudes obey a specific relation so that the system may be mapped to a corresponding Hermitian one and its energy spectrum is completely real. Analogous to the Hermitian case, one may use the modified winding number to determine the total number of edge states on the boundaries to achieve a modified bulk-boundary correspondence. Due to the skin effect in nonHermitian systems, the spectral winding numbers must be used to classify such systems further. It dictates how the edge states would be distributed over the left and right boundaries. We then naively extend the criteria to the cases that the quasi Hermitian condition is violated. For all the cases that we consider, no inconsistency has been found.Comment: 21 pages, 10 figure

Experimental and Numerical Study of Tsunami Wave Propagation and Run-Up on Sloping Beaches

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

18F-FDG PET/CT-based gross tumor volume definition for radiotherapy in head and neck Cancer: a correlation study between suitable uptake value threshold and tumor parameters

<p>Abstract</p> <p>Background</p> <p>To define a suitable threshold setting for gross tumor volume (GTV) when using ¹⁸Fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in head and neck cancer (HNC).</p> <p>Methods</p> <p>Fifteen HNC patients prospectively received PET/CT simulation for their radiation treatment planning. Biological target volume (BTV) was derived from PET/CT-based GTV of the primary tumor. The BTVs were defined as the isodensity volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax), excluding any artifact from surrounding normal tissues. CT-based primary GTV (C-pGTV) that had been previously defined by radiation oncologists was compared with the BTV. Suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level was observed to be the best fitness of the C-pGTV. Suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax.</p> <p>Results</p> <p>Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the C-pGTV. The sTL was 13% to 27% (mean, 19%), whereas the sSUV was 1.64 to 3.98 (mean, 2.46). The sTL was inversely correlated with the SUVmax [sTL = -0.1004 Ln (SUVmax) + 0.4464; R²= 0.81]. The sSUV showed a linear correlation with the SUVmax (sSUV = 0.0842 SUVmax + 1.248; R²= 0.89). The sTL was not associated with the value of C-pGTVs.</p> <p>Conclusion</p> <p>In PET/CT-based BTV for HNC, a suitable threshold or SUV level can be established by correlating with SUVmax rather than using a fixed threshold.</p

The relationship of muscular endurance and coordination and dexterity with behavioral and neuroelectric indices of attention in preschool children

This study investigated the associations of non-aerobic fitness (NAF) and motor competence (MC) with attention in 4–6 year-old preschoolers. The allocation of attentional resources and speed of stimulus categorization were examined using the amplitude and latency of P3 of event-related potentials respectively, while cortical activation related to general attention and task-specific discriminative processes were examined using event-related desynchronization (ERD) at lower (8–10 Hz) and upper (10–12 Hz) alpha frequencies, respectively. Seventy-six preschoolers completed NAF (muscular power, muscular endurance, flexibility, balance) and MC (coordination and dexterity, ball skills, agility and balance) test batteries. Electroencephalogram was recorded while participants performed an auditory oddball task. After controlling for age and MC, muscular endurance was positively related to P3 amplitude. MC and its coordination and dexterity sub-component were positively related to task performance, with higher levels of coordination and dexterity showing an additional association with greater upper alpha ERD between 700 and 1000 ms following stimulus onset after controlling for age and NAF. These findings suggest relationships of NAF and MC with early childhood neurocognitive function. Specifically, muscular endurance is related to the neuroinhibition in facilitating effective allocation of attentional resources to stimulus evaluation while coordination and dexterity are related to cortical activation underlying strategic attentional preparation for subsequent stimulus evaluation

External stimulus-responsive biomaterials designed for the culture and differentiation of ES, iPS, and adult stem cells

The physical and chemical characteristics of biomaterial surface and hydrogels can be altered by external stimuli, such as light irradiation, temperature changes, pH shifts, shear stress forces, electrical forces, and the addition of small chemical molecules. Such external stimulus-responsive biomaterials represent promising candidates that have been developed for the culture and differentiation of embryonic stem (ES) cells, induced pluripotent stem (iPS) cells, and adult stem cells. Biomaterials that are designed to respond in a reversible manner to specific external signals can be formed on micropatterned or non-micropatterned surface, in hydrogels, or on microcarriers. Stem cells and the cells differentiated from them into specific tissue lineages can be cultured and/or differentiated on dishes with immobilized external stimulus-responsive polymers. Cells can be detached from these dishes without using an enzymatic digestion method or a mechanical method when the appropriate external stimulus is generated on the surface. This review discusses the polymers and polymeric designs employed to produce surface and hydrogels for stem cell culture, differentiation, and/or cell detachment using various external stimuli

Sitagliptin and Fractures in Type 2 Diabetes: A Nationwide Population-Based Propensity-Matching Study

Background: Sitagliptin, a dipeptidyl peptidase-4 inhibitor possibly affects bone turnover. We conducted this cohort study to determine whether sitagliptin is associated with an increased risk of fracture.Methods: The sitagliptin cohort included 1,578 patients aged 20 years and above. The nonsitagliptin cohort comprised propensity-score matched patients at a ratio of 1:1. The primary outcome was the incidence of fractures, which was evaluated using Kaplan–Meier survival analysis and proportional hazards modeling.Results: The mean age of patients in the sitagliptin and nonsitagliptin cohorts was 63.1 and 63.3 years, respectively. The incidence of fractures in the sitagliptin cohort was 46 per 1,000 person-years and that in the nonsitagliptin cohort was 40.8 per 1,000 person-years. Compared with patients in the nonsitagliptin cohort, those in the sitagliptin cohort who received sitagliptin for ≥250 days had a higher risk of fracture (aHR = 1.32, 95% CI = 1.06–1.64).Conclusion: Using sitaglipin ≥250 days was associated with an increased risk of fracture