The Vascular Response to Consumption of Different Sugar Types in Adolescents

Cardiovascular disease (CVD) is the leading global cause of mortality and the underlying atherosclerotic disease process which precedes overt CVD originates in youth. Consumption of sugar-sweetened beverages (SSB) are associated with CVD risk factors in youth and SSB intake is a key contributor to added dietary sugar intake in teenagers in the United Kingdom. Endothelial dysfunction is a prerequisite for atherosclerosis and previous research demonstrates that SSB consumption acutely impairs endothelial function. However, these studies have predominantly focused on adult populations, or have used a glucose bolus which is not representative of the sugar found in commercially available SSBs. The purpose of this thesis was to investigate the influence of different dietary sugars found in SSBs on macrovascular and microvascular outcomes and then observe whether the sugar type influences the cardiometabolic responses to a subsequent test meal challenge. This thesis also determined the reliability of measures for the assessment of macrovascular (flow-mediated dilation; FMD) and microvascular (laser Doppler flowmetry) function. Chapter 4: Assessed the within-day and between day reliability of the simultaneous assessment of macrovascular and microvascular function. The within-day and between-day typical error expressed as a coefficient of variation were as follows: FMD, 7.2% and 8.0%; peak reactive hyperaemia (PRH), 24.5% and 26.1%. These results determined that the reliability of outcomes in this study were consistent with existing paediatric data. Chapter 5: There was a large (ηp2=0.27) but not significant (P=0.06) interaction effect for FMD. There was a non-significant difference between the sucrose and control trials for FMD at 1 hour post drink consumption (P=0.06) and 3 hours post test meal consumption (P=0.09) but there was a medium effect at both times with effect sizes of 0.77 and 0.65, respectively, where FMD increased following sucrose consumption. PRH increased 1 hour post drink consumption in the fructose (P=0.01), glucose (P=0.04) and sucrose trials (P=0.04) when compared to control. PRH was greater in the fructose trial when compared to the control (P=0.03), glucose (P=0.01) and sucrose (P=0.02) trials. These findings suggest that SSB intake acutely improves macro- and micro- vascular function in adolescents. Overall, these findings provide important information in regards to the effects of SSBs on macrovascular and microvascular function in adolescents

Aerosol-Assisted Chemical Vapor Deposited Thin Films for Space Photovoltaics

Copper indium disulfide thin films were deposited via aerosol-assisted chemical vapor deposition using single source precursors. Processing and post-processing parameters were varied in order to modify morphology, stoichiometry, crystallography, electrical properties, and optical properties in order to optimize device-quality material. Growth at atmospheric pressure in a horizontal hot-wall reactor at 395 C yielded best device films. Placing the susceptor closer to the evaporation zone and flowing a more precursor-rich carrier gas through the reactor yielded shinier, smoother, denser-looking films. Growth of (112)-oriented films yielded more Cu-rich films with fewer secondary phases than growth of (204)/(220)-oriented films. Post-deposition sulfur-vapor annealing enhanced stoichiometry and crystallinity of the films. Photoluminescence studies revealed four major emission bands (1.45, 1.43, 1.37, and 1.32 eV) and a broad band associated with deep defects. The highest device efficiency for an aerosol-assisted chemical vapor deposited cell was 1.03 percent

Implementing textural features on GPUs for improved real-time pavement distress detection

The condition of municipal roads has deteriorated considerably in recent years, leading to large scale pavement distress such as cracks or potholes. In order to enable road maintenance, pavement distress should be timely detected. However, manual investigation, which is still the most widely applied approach toward pavement assessment, puts maintenance personnel at risk and is time-consuming. During the last decade, several efforts have been made to automatically assess the condition of the municipal roads without any human intervention. Vehicles are equipped with sensors and cameras in order to collect data related to pavement distress and record videos of the pavement surface. Yet, this data are usually not processed while driving, but instead it is recorded and later analyzed off-line. As a result, a vast amount of memory is required to store the data and the available memory may not be sufficient. To reduce the amount of saved data, the authors have previously proposed a graphics processing units (GPU)-enabled pavement distress detection approach based on the wavelet transform of pavement images. The GPU implementation enables pavement distress detection in real time. Although the method used in the approach provides very good results, the method can still be improved by incorporating pavement surface texture characteristics. This paper presents an implementation of textural features on GPUs for pavement distress detection. Textural features are based on gray-tone spatial dependencies in an image and characterize the image texture. To evaluate the computational efficiency of the GPU implementation, performance tests are carried out. The results show that the speedup achieved by implementing the textural features on the GPU is sufficient to enable real-time detection of pavement distress. In addition, classification results obtained by applying the approach on 16,601 pavement images are compared to the results without integrating textural features. There results demonstrate that an improvement of 27% is achieved by incorporating pavement surface texture characteristics

The reliability of a breath‐hold protocol to determine cerebrovascular reactivity in adolescents

This is the published version. Available on open access from Wiley via the DOI in this recordPurpose Cerebrovascular reactivity (CVR) is impaired in adolescents with cardiovascular disease risk factors. A breath‐hold test is a noninvasive method of assessing CVR, yet there are no reliability data of this outcome in youth. This study aimed to assess the reliability of a breath‐hold protocol to measure CVR in adolescents. Methods Twenty‐one 13 to 15 year old adolescents visited the laboratory on two separate occasions, to assess the within‐test, within‐day and between‐day reliability of a breath‐hold protocol, consisting of three breath‐hold attempts. CVR was defined as the relative increase from baseline in middle cerebral artery mean blood velocity following a maximal breath‐hold of up to 30 seconds, quantified via transcranial Doppler ultrasonography. Results Mean breath‐hold duration and CVR were never significantly correlated (r  .08). The within‐test coefficient of variation for CVR was 15.2%, with no significant differences across breath‐holds (P = .88), so the three breath‐hold attempts were averaged for subsequent analyses. The within‐ and between‐day coefficients of variation for CVR were 10.8% and 15.3%, respectively. Conclusions CVR assessed via a three breath‐hold protocol can be reliably measured in adolescents, yielding similar within‐ and between‐day reliability. Analyses revealed that breath‐hold length and CVR were unrelated, indicating the commonly reported normalization of CVR to breath‐hold duration (breath‐hold index) may be unnecessary in youth

The acute and postprandial effects of sugar moiety on vascular and metabolic health outcomes in adolescents

This is the author accepted manuscript. The final version is available from Canadian Science Publishing via the DOI in this recordThis study explored the cardiometabolic responses to sugar moieties acutely, and following a subsequent mixed meal tolerance test (MMTT). Twenty-one healthy adolescents (N=10 female, 14.3±0.4 years) completed three experimental and one control condition, in a counterbalanced order. These consisted of different drinks to compare the effect of 300 mL of water (control), or 300 mL of water mixed with 60 g of glucose, fructose or sucrose, on vascular function (flow-mediated dilation; FMD, microvascular reactivity (total hyperaemic response; TRH); and cerebrovascular reactivity; CVR), and blood samples for [uric acid], [glucose], [triglycerides] and [lactate]. FMD increased 1 hour after glucose and sucrose (P<0.001, ES≥0.92) but was unchanged following fructose and water (P>0.19, ES>0.09). CVR and TRH were unchanged 1 hour following all conditions (P>0.57, ES>0.02). Following the MMTT, FMD was impaired in all conditions (P0.40) with no differences between conditions (P>0.13, ES<0.39). Microvascular TRH was increased in all conditions (P=0.001, ES=0.88), and CVR was preserved in all conditions post MMTT (P=0.87, ES=0.02). Blood [uric acid] was elevated following fructose consumption and the MMTT (P0.40). Consumption of a sugar sweetened beverage did not result in vascular dysfunction in healthy adolescents, however the vascular and metabolic responses were dependent on sugar moiety

Disorder-induced Room Temperature Ferromagnetism in Glassy Chromites

[[abstract]]We report an unusual robust ferromagnetic order above room temperature upon amorphization of perovskite [YCrO3] in pulsed laser deposited thin films. This is contrary to the usual expected formation of a spin glass magnetic state in the resulting disordered structure. To understand the underlying physics of this phenomenon, we combine advanced spectroscopic techniques and first-principles calculations. We find that the observed order-disorder transformation is accompanied by an insulator-metal transition arising from a wide distribution of Cr-O-Cr bond angles and the consequent metallization through free carriers. Similar results also found in YbCrO3-films suggest that the observed phenomenon is more general and should, in principle, apply to a wider range of oxide systems. The ability to tailor ferromagnetic order above room temperature in oxide materials opens up many possibilities for novel technological applications of this counter intuitive effect.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]電子版[[countrycodes]]GB

A ‘Baby GDA’: Norwich’s Airspace during the Second World War

Throughout the Second World War, the Luftwaffe attacked Norwich on various occasions. The impact this had on the city was recorded visually on the ‘Norwich Bomb Map’. This cartographic depiction, however, only records a single ‘horizontal’ component of the aerial ‘battlescape’. In reality, the aerial battlefield comprised a combination of Norwich’s air defences and the flightpaths of the Luftwaffe bombers, which existed in three-dimensional space. As other scholars have developed methodologies for reconstructing anti-aircraft ‘fire domes’, this article will combine these concepts with a new approach that reconstructs historic flightpaths to give a three-dimensional overview of Norwich’s ‘Gun Defended Area’. By examining all components of Norwich’s airspace, this article will demonstrate the importance of considering the vertical component of a battlescape