Mechanical Characterisation of Confectionery Wafers

The aim of this research is to model the deformation and fracture behaviour of wafers used in chocolate confectionery products. Compression and bending tests showed that the mechanical behaviour of the wafer was characteristic of a brittle foam. The wafer sheet was examined with a Scanning Electron Microscope (SEM) to determine the wafer dimensions and to observe the internal microstructure. These images showed that the core of the wafer sheet was more porous than the dense skins of the wafer. An analytical model was developed to calculate the modulus of the wafer core and skin sections. A finite element (FE) model using a simple repetitive geometry of the wafer was implemented. The ‘crushable foam’ material model was the closest fit to the wafer deformation under compression and was applied to the core of the wafer. An alternative FE model was proposed, which used the actual complex architecture of the wafer. To attain the wafer architecture, X-ray Microtomography (XMT) was used on a sample to produce a stack of image slices which were reconstructed as a 3D volume. The microstructure of the 3D volume was characterised and then meshed with tetrahedral elements for finite element analysis. The cell walls of the model were given a linear elastic material model and a damage criterion to simulate the fracture of the cell walls. In-situ SEM and XMT experiments were conducted which allowed the deformation and fracture of the wafer sheet to be observed simultaneously as the global mechanical response was recorded. The FE model of the complex architecture was able to predict the deformation behaviour of the wafer in compression. In the future, the model can be used to simulate the cutting process of the wafer, allowing the effect of parameters such as cutting speed and blade dimensions to be determined efficiently

Dissecting the Contribution of the Carboxyl-Terminal Domain and Tail of HIV-1 Integrase to Viral Dynamics and Enzymatic Function

The Human Immunodeficiency Virus Type-1 (HIV-1) is the causative agent of the Acquired Immune Deficiency Syndrome (AIDS). Combination antiviral therapy has proven to be particularly effective at suppressing viral replication, yet complete eradication of the virus from an infected individual remains elusive. Recently, a new class of antiviral drugs targeting the viral integrase (IN) has been added to the HAART (high active antiretroviral therapy) regimen. This novel drug class exerts its inhibitory effect by targeting one aspect of the dual-staged integration reaction. In contrast to the other two viral targets of HAART, the reverse transcriptase (RT) and protease (PR) enzymes, both of which have singular roles in viral replication, IN contributes a plurality of functions to the viral life cycle, thus potentiating the development for further therapeutic intervention. In spite of the intensity of investigation in the field, the mechanistic details of several aspects of IN activity, especially of its ancillary functions remain unclear. This thesis work focuses primarily on dissecting the contribution of the carboxyl-terminal domain (CTD), in particular the terminal 18 amino acid ‘tail’ of this domain, to both the primary integration activities and secondary functions of IN. This was accomplished by conducting a survey of incremental deletions aimed at gradually removing this region of the protein, and testing the resulting viruses in a number of measurable assays of virologic function. In so doing we identified a number of anomalous mutant phenotypes, the ensuing characterization of which should contribute to better understanding the roles of IN with regard to both its primary and secondary functions in the replicative strategy of HIV-1

Quantifying substructures in {\it Hubble Frontier Field} clusters: comparison with ΛCDM\Lambda CDM simulations

The Hubble Frontier Fields (HFF) are six clusters of galaxies, all showing indications of recent mergers, which have recently been observed for lensed images. As such they are the natural laboratories to study the merging history of galaxy clusters. In this work, we explore the 2D power spectrum of the mass distribution $P_{\rm M}(k)$ as a measure of substructure. We compare $P_{\rm M}(k)$ of these clusters (obtained using strong gravitational lensing) to that of $\Lambda$CDM simulated clusters of similar mass. To compute lensing $P_{\rm M}(k)$, we produced free-form lensing mass reconstructions of HFF clusters, without any light traces mass (LTM) assumption. The inferred power at small scales tends to be larger if (i)~the cluster is at lower redshift, and/or (ii)~there are deeper observations and hence more lensed images. In contrast, lens reconstructions assuming LTM show higher power at small scales even with fewer lensed images; it appears the small scale power in the LTM reconstructions is dominated by light information, rather than the lensing data. The average lensing derived $P_{\rm M}(k)$ shows lower power at small scales as compared to that of simulated clusters at redshift zero, both dark-matter only and hydrodynamical. The possible reasons are: (i)~the available strong lensing data are limited in their effective spatial resolution on the mass distribution, (ii)~HFF clusters have yet to build the small scale power they would have at $z\sim 0$, or (iii)~simulations are somehow overestimating the small scale power.Comment: 13 pages, 10 figures, 1 table; Accepted for publication in MNRA

Characterization of three vasopressin receptor 2 variants: an apparent polymorphism (V266A) and two loss-of-function mutations (R181C and M311V).

Arginine vasopressin (AVP) is released from the posterior pituitary and controls water homeostasis. AVP binding to vasopressin V2 receptors (V2Rs) located on kidney collecting duct epithelial cells triggers activation of Gs proteins, leading to increased cAMP levels, trafficking of aquaporin-2 water channels, and consequent increased water permeability and antidiuresis. Typically, loss-of-function V2R mutations cause nephrogenic diabetes insipidus (NDI), whereas gain-of-function mutations cause nephrogenic syndrome of inappropriate antidiuresis (NSIAD). Here we provide further characterization of two mutant V2Rs, R181C and M311V, reported to cause complete and partial NDI respectively, together with a V266A variant, in a patient diagnosed with NSIAD. Our data in HEK293FT cells revealed that for cAMP accumulation, AVP was about 500- or 30-fold less potent at the R181C and M311V mutants than at the wild-type receptor respectively (and about 4000- and 60-fold in COS7 cells respectively). However, in contrast to wild type V2R, the R181C mutant failed to increase inositol phosphate production, while with the M311V mutant, AVP exhibited only partial agonism in addition to a 37-fold potency decrease. Similar responses were detected in a BRET assay for β-arrestin recruitment, with the R181C receptor unresponsive to AVP, and partial agonism with a 23-fold decrease in potency observed with M311V in both HEK293FT and COS7 cells. Notably, the V266A V2R appeared functionally identical to the wild-type receptor in all assays tested, including cAMP and inositol phosphate accumulation, β-arrestin interaction, and in a BRET assay of receptor ubiquitination. Each receptor was expressed at comparable levels. Hence, the M311V V2R retains greater activity than the R181C mutant, consistent with the milder phenotype of NDI associated with this mutant. Notably, the R181C mutant appears to be a Gs protein-biased receptor incapable of signaling to inositol phosphate or recruiting β-arrestin. The etiology of NSIAD in the patient with V266A V2R remains unknown

Percutaneous elastic intramedullary nailing of metacarpal fractures: Surgical technique and clinical results study

<p>Abstract</p> <p>Background</p> <p>We reviewed our results and complications of using a pre-bent 1.6 mm Kirschner wire (K-wire) for extra-articular metacarpal fractures. The surgical procedure was indicated for angulation at the fracture site in a true lateral radiograph of at least 30 degrees and/or in the presence of a rotatory deformity.</p> <p>Methods</p> <p>A single K-wire is pre-bent in a lazy-S fashion with a sharp bend at approximately 5 millimeters and a longer smooth curve bent in the opposite direction. An initial entry point is made at the base of the metacarpal using a 2.5 mm drill by hand. The K-wire is inserted blunt end first in an antegrade manner and the fracture reduced as the wire is passed across the fracture site. With the wire acting as three-point fixation, early mobilisation is commenced at the metacarpo-phalangeal joint in a Futuro hand splint.</p> <p>The wire is usually removed with pliers post-operatively at four weeks in the fracture clinic.</p> <p>Results</p> <p>We studied internal fixation of 18 little finger and 2 ring finger metacarpal fractures from November 2007 to August 2009. The average age of the cohort was 25 years with 3 women and 17 men. The predominant mechanism was a punch injury with 5 diaphyseal and 15 metacarpal neck fractures. The time to surgical intervention was a mean 13 days (range 4 to 28 days). All fractures proceeded to bony union. The wire was extracted at an average of 4.4 weeks (range three to six weeks). At an average follow up of 8 weeks, one fracture had to be revised for failed fixation and three superficial wound infections needed antibiotic treatment.</p> <p>Conclusions</p> <p>With this simple and minimally invasive technique performed as day-case surgery, all patients were able to start mobilisation immediately. The general outcome was good hand function with few complications.</p

Performance of externally validated enhanced computer-aided versions of the National Early Warning Score in predicting mortality following an emergency admission to hospital in England: a cross-sectional study

Objectives: In the English National Health Service, the patient’s vital signs are monitored and summarised into a National Early Warning Score (NEWS) to support clinical decision making, but it does not provide an estimate of the patient’s risk of death. We examine the extent to which the accuracy of NEWS for predicting mortality could be improved by enhanced computer versions of NEWS (cNEWS). Design: Logistic regression model development and external validation study. Setting: Two acute hospitals (YH—York Hospital for model development; NH—Northern Lincolnshire and Goole Hospital for external model validation). Participants: Adult (≥16 years) medical admissions discharged over a 24-month period with electronic NEWS (eNEWS) recorded on admission are used to predict mortality at four time points (in-hospital, 24 hours, 48 hours and 72 hours) using the first electronically recorded NEWS (model M0) versus a cNEWS model which included age+sex (model M1) +subcomponents of NEWS (including diastolic blood pressure) (model M2). Results: The risk of dying in-hospital following emergency medical admission was 5.8% (YH: 2080/35 807) and 5.4% (NH: 1900/35 161). The c-statistics for model M2 in YH for predicting mortality (in-hospital=0.82, 24 hours=0.91, 48 hours=0.88 and 72 hours=0.88) was higher than model M0 (in-hospital=0.74, 24 hours=0.89, 48 hours=0.86 and 72 hours=0.85) with higher Positive Predictive Value (PPVs) for in-hospital mortality (M2 19.3% and M0 16.6%). Similar findings were seen in NH. Model M2 performed better than M0 in almost all major disease subgroups.Conclusions: An externally validated enhanced computer-aided NEWS model (cNEWS) incrementally improves on the performance of a NEWS only model. Since cNEWS places no additional data collection burden on clinicians and is readily automated, it may now be carefully introduced and evaluated to determine if it can improve care in hospitals that have eNEWS systems

Object-based assessment of tree attributes of Acacia tortilis in Bou-Hedma, Tunisia

Acacia tortilis subsp. raddiana represents the most important woody species in the pre-Saharan zone. It is the only forest tree persisting on the edge of the desert. Due to tree/environment interactions, canopy sub-habitats arise, enabling an increased storage of soil water, soil nutrients and soil oxygen. Depending on their density, they can also reduce erosion and reverse desertification. Soil erosion and desertification are the main problems faced by the UNESCO Biosphere Reserve in South-Tunisia (Bou-Hedma National Park). The restoration of the original woodland cover to combat desertification (particularly) by afforestation and reforestation of Acacia tortilis goes hand in hand with a climate change in the Biosphere Reserve, also influencing rural population outside the Biosphere Reserve. In order to study the different effects of woodland restoration in Bou-Hedma, the number of Acacia trees and their attributes have to be known. High resolution satellite imagery (GeoEye-1), was used with a GEOBIA approach. Field measurement of bole diameter, crown diameter and tree height were collected at > 400 locations. After segmentation, correlations with > 200 object features and tree attributes were calculated. For crown diameter and tree height, high correlations were observed with the features area and GLCM Entropy Layer 4 (90 degrees). Relations between these features and measured tree attributes were modeled, resulting in RMSE values of resp. 1.47 m and 1.62 m for crown diameter estimation and 0.92 m for tree height. The results show that a GEOBIA working strategy is suitable for estimating tree attributes in open forests in semi-arid regions

Hydrogen Gas Production from the Injection of Nanoscale Zero-Valent Iron and Sodium Borohydride Solutions: Potential Effects Near Injection Wells

The injection of nano-scale zero-valent iron (nZVI) is a remediation technique for the treatment of organic and metal contamination in soil and groundwater. The hydrogen gas (H2) produced during the reaction of nZVI and excess sodium borohydride (NaBH4) used in nZVI synthesis with water can inhibit nZVI transport in the subsurface, potentially limiting solution delivery to the target contaminant zone. Laboratory experiments were completed in a thin flow cell using NaBH4 and nZVI solutions injected into watersaturated medium sands, in which local gas saturations were quantified using a light transmission technique to calculate H2 gas volumes. Hydraulic conductivity, under water-saturated and quasi-saturated conditions, after gas exsolution and throughout gas dissolution, was measured. The results showed that H2 gas volume produced as a result of the reaction of nZVI with water was more than the H2 gas volume produced by the selfhydrolysis of NaBH4 solution regardless of similar NaBH4 concentration used as excess during nZVI synthesis. Pools of H2 gas were formed after injecting nZVI prepared with excess 5 g/L NaBH4 or after injecting 5 g/L NaBH4 without nZVI. Gas accumulated predominantly in a vertical layer of coarse sand, illustrative of a sand pack surrounding an injection well. Lower hydraulic conductivity measurements were linked to higher gas saturations and further reductions were evident as a result of gas pool accumulation at the top of the flow cell. These results show that gas production during the application of nZVI is an important process that must be considered during remediation design and operation to ensure effective delivery to target zones

Terminal 77

Located south of Dallas, Texas, on Highway 77, a 550,000 sf site was transformed into a fueling station for Semi-trailer trucks. Creating a set of parameters, such as vehicular type, turn radius, and maximum vehicle dimensions, a systematic approach was organized in which to cultivate an architecture. The fueling station was reduced to three components: an area to fuel, an area to park, and an area leading to amenities. Researching the audience that would occupy the architecture, it was found that a further separation between the public and the truck drivers would be necessary. The solution was to make a fueling station that harbors a triple story configuration: the Trucker’s Haven, the People’s Haven and the Meditation Haven. This allowed the much disrespected truck driver a private plane on which they could affect an honorable existence. If need be, truckers could leave this haven, emerging on the upper most level, signaling a poetical release and meditative transformation. Reflecting on the fast pace nature of contemporary mass-transportation of goods and products, the meditation chamber was inserted into the canopy of the uppermost structure, violating a space that would otherwise be purely mechanical, in order to slow down the pace of daily rituals and allow a sense of exploration and removal from a culture of constant movement

Student Mastery or AI Deception? Analyzing ChatGPT's Assessment Proficiency and Evaluating Detection Strategies

Generative AI systems such as ChatGPT have a disruptive effect on learning and assessment. Computer science requires practice to develop skills in problem solving and programming that are traditionally developed using assignments. Generative AI has the capability of completing these assignments for students with high accuracy, which dramatically increases the potential for academic integrity issues and students not achieving desired learning outcomes. This work investigates the performance of ChatGPT by evaluating it across three courses (CS1,CS2,databases). ChatGPT completes almost all introductory assessments perfectly. Existing detection methods, such as MOSS and JPlag (based on similarity metrics) and GPTzero (AI detection), have mixed success in identifying AI solutions. Evaluating instructors and teaching assistants using heuristics to distinguish between student and AI code shows that their detection is not sufficiently accurate. These observations emphasize the need for adapting assessments and improved detection methods.Comment: 7 pages, Published in 2023 International Conference on Computational Science and Computational Intelligence Research Track on Education, IEEE CP