A Quantitative Study of In Vivo Protoporphyrin IX Fluorescence Build Up During Occlusive Treatment Phases

C L Campbell acknowledges financial support from an UK EPSRC PhD studentship (EP/K503162/1), the Alfred Stewart Trust, the Russell trust award, the Santander mobility award and the FAPESP CEPOF grant 2013/07276.Background: Topical photodynamic therapy (PDT) is a non-invasive light based therapy used to treat non-melanoma skin cancer (NMSC) and dysplasia. During PDT, the light sensitive molecule protoporphyrin IX (PpIX) is activated, resulting in the production of singlet oxygen, which subsequently leads to cell death. PpIX is metabolised from a topically applied pro-drug and the strong fluorescence signal associated with PpIX can be utilised as an indicator of the amount of PpIX present within the tumour tissue. In this work we measure the build up PpIX during the occlusive treatment phase and investigate how the PpIX production rate is affected by different lesion and patient characteristics. Methods : Fluorescence measurements were used to investigate the build up of PpIX within the tumour tissue during the 3 hour long occlusive treatment prior to irradiation. The study included in vivo measurements of 38 lesions from 38 individual patients. Actinic keratosis (AK) and basal cell carcinoma (BCC) were the lesion types included in this study. The resulting data from the study was analysed using generalised linear mixed effects models. Results : It was found that the surface fluorescence signal linearly increased with occlusive treatment time. The predictive models suggest that there is a significant difference in PpIX production between lesion location, however no significant difference is demonstrated between different lesion types, gender and skin type. Conclusions : The study extends and supports previous knowledge of PpIX production during the occlusive treatment phase.PostprintPeer reviewe

Роль научно-технической олимпиады в развитии интереса к профессиональной деятельности учащихся

We acknowledge the support of the UK Engineering and Physics Sciences Research Council (EPSRC) for funding through a studentship for C L Campbell (EP/K503162/1), the Alfred Stewart Trust as well as the BMLA Education Award.Photodynamic therapy (PDT) has been theoretically investigated using a Monte Carlo radiation transfer (MCRT) model. By including complex three dimensional (3D) tumour models a more appropriate representation of the treatment was achieved. The 3D clustered tumour model was compared to a smooth model, resulting in a significantly deeper penetration associated with the clustered model. The results from the work presented here indicates that light might penetrate deeper than suggested by 2D or simple layered models.Publisher PD

Controlled core-to-core photo-polymerisation – fabrication of an optical fibre-based pH sensor

The fabrication of fluorescence-based pH sensors, embedded into etched pits of an optical fibre via highly controllable and spatially selective photo-polymerisation is described and the sensors validated.</p

Computational Fluorescence Suppression in Shifted Excitation Raman Spectroscopy

Fiber-based Raman spectroscopy in the context of &lt;italic&gt;in vivo&lt;/italic&gt; biomedical application suffers from the presence of background fluorescence from the surrounding tissue that might mask the crucial but inherently weak Raman signatures. One method that has shown potential for suppressing the background to reveal the Raman spectra is shifted excitation Raman spectroscopy (SER). SER collects multiple emission spectra by shifting the excitation by small amounts and uses these spectra to computationally suppress the fluorescence background based on the principle that Raman spectrum shifts with excitation while fluorescence spectrum does not. We introduce a method that utilizes the spectral characteristics of the Raman and fluorescence spectra to estimate them more effectively, and compare this approach against existing methods on real world datasets.</p

Determinants of medication adherence to antihypertensive medications among a Chinese population using Morisky medication adherence scale

&lt;b&gt;Background and objectives&lt;/b&gt; Poor adherence to medications is one of the major public health challenges. Only one-third of the population reported successful control of blood pressure, mostly caused by poor drug adherence. However, there are relatively few reports studying the adherence levels and their associated factors among Chinese patients. This study aimed to study the adherence profiles and the factors associated with antihypertensive drug adherence among Chinese patients.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; A cross-sectional study was conducted in an outpatient clinic located in the New Territories Region of Hong Kong. Adult patients who were currently taking at least one antihypertensive drug were invited to complete a self-administered questionnaire, consisting of basic socio-demographic profile, self-perceived health status, and self-reported medication adherence. The outcome measure was the Morisky Medication Adherence Scale (MMAS-8). Good adherence was defined as MMAS scores greater than 6 points (out of a total score of 8 points).&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt; From 1114 patients, 725 (65.1%) had good adherence to antihypertensive agents. Binary logistic regression analysis was conducted. Younger age, shorter duration of antihypertensive agents used, job status being employed, and poor or very poor self-perceived health status were negatively associated with drug adherence.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusion&lt;/b&gt; This study reported a high proportion of poor medication adherence among hypertensive subjects. Patients with factors associated with poor adherence should be more closely monitored to optimize their drug taking behavior

Sub millimetre flexible fibre probe for background and fluorescence free Raman spectroscopy

Using the shifted-excitation Raman difference spectroscopy technique and an optical fibre featuring a negative curvature excitation core and a coaxial ring of high numerical aperture collection cores, we have developed a portable, background and fluorescence free, endoscopic Raman probe. The probe consists of a single fibre with a diameter of less than 0.25 mm packaged in a sub-millimetre tubing, making it compatible with standard bronchoscopes. The Raman excitation light in the fibre is guided in air and therefore interacts little with silica, enabling an almost background free transmission of the excitation light. In addition, we used the shifted-excitation Raman difference spectroscopy technique and a tunable 785 nm laser to separate the fluorescence and the Raman spectrum from highly fluorescent samples, demonstrating the suitability of the probe for biomedical applications. Using this probe we also acquired fluorescence free human lung tissue data

Quantifying Inactive Lithium in Lithium Metal Batteries

Inactive lithium (Li) formation is the immediate cause of capacity loss and catastrophic failure of Li metal batteries. However, the chemical component and the atomic level structure of inactive Li have rarely been studied due to the lack of effective diagnosis tools to accurately differentiate and quantify Li+ in solid electrolyte interphase (SEI) components and the electrically isolated unreacted metallic Li0, which together comprise the inactive Li. Here, by introducing a new analytical method, Titration Gas Chromatography (TGC), we can accurately quantify the contribution from metallic Li0 to the total amount of inactive Li. We uncover that the Li0, rather than the electrochemically formed SEI, dominates the inactive Li and capacity loss. Using cryogenic electron microscopies to further study the microstructure and nanostructure of inactive Li, we find that the Li0 is surrounded by insulating SEI, losing the electronic conductive pathway to the bulk electrode. Coupling the measurements of the Li0 global content to observations of its local atomic structure, we reveal the formation mechanism of inactive Li in different types of electrolytes, and identify the true underlying cause of low Coulombic efficiency in Li metal deposition and stripping. We ultimately propose strategies to enable the highly efficient Li deposition and stripping to enable Li metal anode for next generation high energy batteries

Computational Fluorescence Suppression in Shifted Excitation Raman Spectroscopy

Fiber-based Raman spectroscopy in the context of &lt;italic&gt;in vivo&lt;/italic&gt; biomedical application suffers from the presence of background fluorescence from the surrounding tissue that might mask the crucial but inherently weak Raman signatures. One method that has shown potential for suppressing the background to reveal the Raman spectra is shifted excitation Raman spectroscopy (SER). SER collects multiple emission spectra by shifting the excitation by small amounts and uses these spectra to computationally suppress the fluorescence background based on the principle that Raman spectrum shifts with excitation while fluorescence spectrum does not. We introduce a method that utilizes the spectral characteristics of the Raman and fluorescence spectra to estimate them more effectively, and compare this approach against existing methods on real world datasets.</p