Legitimization & De-legitimization of Police: In British Colonial & Chinese SAR Hong Kong

departmental bulletin pape

Experimental investigation of flow-induced vibration of a rotating circular cylinder

While flow-induced vibration of bluff bodies has been extensively studied over the last half-century, only limited attention has been given to flow-induced vibration of elastically mounted rotating cylinders. Since recent low-Reynolds-number numerical work suggests that rotation can enhance or suppress the natural oscillatory response, the former could find applications in energy harvesting and the latter in vibration control. The present experimental investigation characterises the dynamic response and wake structure of a rotating circular cylinder undergoing vortex-induced vibration at a low mass ratio (m∗ = 5.78) over the reduced velocity range leading to strong oscillations. The experiments were conducted in a free-surface water channel with the cylinder vertically mounted and attached to a motor that provided constant rotation. Springs and an air-bearing system allow the cylinder to undertake low-damped transverse oscillations. Under cylinder rotation, the normalised frequency response was found to be comparable to that of a freely vibrating non-rotating cylinder. At reduced velocities consistent with the upper branch of a non-rotating transversely oscillating cylinder, the maximum oscillation amplitude increased with non-dimensional rotation rate up to α ≈ 2. Beyond this, there was a sharp decrease in amplitude. Notably, this critical value corresponds approximately to the rotation rate at which vortex shedding ceases for a non-oscillating rotating cylinder. Remarkably, at α = 2 there was approximately an 80% increase in the peak amplitude response compared to that of a non-rotating cylinder. The observed amplitude response measured over the Reynolds-number range of (1100 Re 6300) is significantly different from numerical predictions and other experimental results recorded at significantly lower Reynolds numbers

Water treatment for hemodialysis

AbstractWater treatment plays a vital role in the delivery of safe and effective hemodialysis (HD). Ensuring that water quality meets the American Association for the Advancement of Medical Instrumentation standards and recommendations (or equivalent) is necessary to reduce the incidence of chemical hazards and endotoxemia associated with the use of water for HD. This review will discuss the principles of water treatment for HD, the essential components of water purification, the recommended system monitoring and maintenance procedures, and some of the historical incidents of adverse reactions that resulted from the use of contaminated dialysis water

Experimental investigation of flow-induced vibration of a sinusoidally rotating circular cylinder

The present experimental investigation characterises the dynamic response and wake structure of a sinusoidally rotating circular cylinder with a low mass ratio (defined as the ratio of the total oscillating mass to the displaced fluid mass) undergoing cross-stream flow-induced vibration (FIV). The study covers a wide parameter space spanning the forcing rotary oscillation frequency ratio

A Facile Method for Separation of the Cryptic Methionine Sulfoxide Diastereomers, Structural Assignment and DFT Analysis

Methionine (Met) oxidation is an important biological redox node, with hundreds if not thousands of protein targets. The process yields methionine oxide (MetO). It renders the sulfur chiral, producing two distinct, diastereomerically related products. Despite the biological significance of Met oxidation, a reliable protocol to separate the resultant MetO diastereomers is currently lacking. This hampers our ability to make peptides and proteins that contain stereochemically defined MetO to then study their structural and functional properties. We have developed a facile method that uses supercritical CO₂ chromatography and allows obtaining both diastereomers in purities exceeding 99 %. ¹H NMR spectra were correlated with X‐ray structural information. The stereochemical interconversion barrier at sulfur was calculated as 45.2 kcal mol⁻¹, highlighting the remarkable stereochemical stability of MetO sulfur chirality. Our protocol should open the road to synthesis and study of a wide variety of stereochemically defined MetO‐containing proteins and peptides

The impact of COVID-19 on the eating habits of families engaged in a healthy eating pilot trial: a thematic analysis.

This is the final version. Available from Taylor & Francis via the DOI in this record. BACKGROUND: The eating habits of children and adults have been impacted by the COVID-19 pandemic, with evidence of increases in snacking and emotional eating, including eating to relieve boredom. We explored the experiences of families with children aged 4-8 years who had recently participated in a healthy eating pilot trial when the first national lockdown began in England. METHODS: Eleven mothers were interviewed in April and May 2020. Interview questions were developed based on the COM-B model of behaviour. Four main themes were constructed using inductive thematic analysis. RESULTS: The first theme related to an initial panic phase, in which having enough food was the primary concern. The second related to ongoing challenges during the lockdown, with sub-themes including difficulties accessing food, managing children's food requests and balancing home and work responsibilities. The perception that energy-dense foods met families' needs during this time led to increased purchasing of (and thus exposure to) energy-dense foods. In the third theme, families described a turning point, with a desire to eat a healthier diet than they had in the early stages of the lockdown. Finally, in the fourth theme, families reported a number of strategies for adapting and encouraging a balanced diet with their children. CONCLUSIONS: Our results suggest that even if parents have the capability (e.g. knowledge) and motivation to provide a healthy diet for their family, opportunity challenges (e.g. time, access to resources, environmental stressors) mean this is not always practical. Healthy eating interventions should not assume parents lack motivation and should be sensitive to the context within which parents make feeding decisions.Economic and Social Research CouncilMedical Research Counci

Generating new dualities through the orbifold equivalence: a demonstration in ABJM and four-dimensional quivers

We show that the recently proposed large $N$ equivalence between ABJM theories with Chern-Simons terms of different rank and level, U(N_1)_{k_1}\times U(N_1)_{-k_1} and U(N_2)_{k_2}\times U(N_2)_{-k_2}, but the same value of N' =N_1 k_1=N_2 k_2, can be explained using planar equivalence in the mirror duals. The combination of S-dualities and orbifold equivalence can be applied to other cases as well, with very appealing results. As an example we show that two different quiver theories with k nodes can be easily shown to be Seiberg dual through the orbifold equivalence, but it requires order k^2 steps to give a proof when Seiberg duality is performed node by node.Comment: 18 pages, 7 figures, minor changes and references adde

The correlation between intracranial arterial calcification and the outcome of reperfusion therapy

Objective: Intracranial arterial calcification (IAC) is a risk factor of ischemic stroke. However, the relationship between IAC patterns and clinical outcome of ischemic stroke remains controversial. We aimed to investigate the correlation between IAC patterns and the effects of reperfusion therapy among acute stroke patients. Methods: Consecutive acute ischemic stroke patients who underwent reperfusion therapy were included. IAC was categorized as intimal or medial. Based on its involvement, IAC was further classified as diffuse or focal. Neurologic dysfunction was assessed by the National Institute of Health stroke scale (NIHSS). Clinical outcome including favorable neurologic outcome (FNO) and early neurologic deterioration (END) were assessed. Results: Of 130 patients, 117 had IAC. Intimal IAC was identified in 74.6% of patients and medial IAC was present in 64.6% of patients. Diffuse IAC was present in 31.5% of patients. All diffuse IACs were medial pattern. Diffuse IAC was associated with higher baseline NIHSS (p = 0.011) and less FNO (p = 0.047). Compared with patients with focal or single diffuse IAC, patients with multiple diffuse IAC had higher baseline NIHSS (p = 0.002) and less FNO (p = 0.024). Multivariable linear regression (p &lt; 0.001) and logistic regression (p = 0.027) suggested that multiple diffuse IAC was associated with higher baseline NIHSS and less FNO. No significant association was found between END and different IAC patterns. Interpretation: Multiple diffuse medial IAC may predict severer neurologic dysfunction and less favorable neurologic outcome after reperfusion therapy in acute stroke patients.</p