170 research outputs found
Analysis of the trend of pH changes of concrete pore solution during the hydration by various analytical methods
The pH is an important parameter in concrete health monitoring. Many studies have been conducted to investigate the environmental elements that influence the pH value of concrete. This study focussed on the investigation of the pore solution in concrete throughout the hydration process during a 90-day timeframe. The concrete pore solution was extracted by ex-situ leaching methods (ESL) including cold water and hot water extraction (CWE and HWE). The pH of the solutions was obtained by various techniques such as titration, direct measurement by pH electrode, back calculation method, and the thermodynamic modelling based on the measured alkali concentrations. For both ex-situ leaching processes, the changes in pH and alkali concentration appear to be similar. Due to the dilution effect of water addition, direct pH measurement with a pH electrode and titration method underestimates the real pH value. The results obtained from the measured alkali concentrations were more reliable and indicated that the pH of the fresh concrete was around 13.1 and increased gradually up to 13.8 with time. Back calculation of the pH of the concrete using the dilution of the H+ ions show the high pH values. Therefore, the actual pH of the concrete pore solution can be evaluated using a thermodynamic modelling based on the alkali content of the extracted solution.acceptedVersio
Recommended from our members
The content of optometric eye examinations for a presbyopic patient presenting with symptoms of flashing lights
Background: Standardised patients (SPs) are the gold standard methodology for evaluating clinical care. This approach was used to investigate the content of optometric eyecare for a presbyopic patient who presented with recent photopsia.
Methods: A total of 102 community optometrists consented to be visited by an actor for a recorded eye examination. This actor received extensive training to enable accurate reporting of the content of the eye examinations, via an audio recording and a checklist completed for each clinical encounter. The actor presented unannounced (incognito) as a 59-year-old patient seeking a private eye examination and complaining of recent onset flashing lights. The results of each clinical encounter were recorded on a pre-designed checklist based on evidence-based reviews on photopsia, clinical guidelines and the views of an expert panel.
Results: The presence of the symptom of photopsia was proactively detected in 87% of cases. Although none of the optometrists visited asked all seven gold standard questions relating to the presenting symptoms of flashing lights, 35% asked four of the seven questions. A total of 85% of optometrists asked the patient if he noticed any floaters in his vision and 36% of optometrists asked if he had noticed any shadows in his vision. The proportion of the tests recommended by the expert panel that were carried out varied from 33 to 100% with a mean of 67%. Specifically, 66% recommended dilated fundoscopy to be carried out either by themselves or by another eyecare practitioner, and 29% of optometrists asked the patient to seek a second opinion regarding the photopsia. Of those who referred, 70% asked for the referral to be on the same day or within a week.
Conclusion: SP encounters are an effective way of measuring clinical care within optometry and should be considered for further comparative measurements of quality of care. As in research using SPs in other healthcare disciplines, our study has highlighted substantial differences between different practitioners in the duration and depth of their clinical investigations. This highlights the fact that not all eye examinations are the same but inherently different and that there is no such thing as a ‘standard sight test’. Future optometric continuing education could focus on history taking, examination techniques and referral guidelines for patients presenting with symptoms of posterior vitreous detachment, retinal breaks and secondary retinal detachment
ADOPTION OF TECHNOLOGY: CRITICAL FACTORS INFLUENCING CONSUMERS' INTENTIONS TO USE MOBILE BANKING IN SRI LANKA
Mobile banking plays a crucial role in modern retail banking, particularly in developing countries like Sri Lanka,
where financial inclusion remains a key challenge. Despite its potential to enhance convenience, accessibility, and efficiency,
adoption rates have been relatively slow due to various influencing factors. This study seeks to examine the critical factors
shaping consumers' behavioral intentions toward mobile banking in Sri Lanka within an evolving Financial and technological
land scape. A cross-sectional Survey design as employed, gathering data from a diverse sample of bank customers to assess
key determinants. The study investigates the effects of social influence, IT innovativeness, performance expectancy, effect
expectancy, environmental benefits, and privacy concerns on mobile banking adoption. Structural equation modeling (SEM)
was used to analyze the relationships between these factors and to test the proposed conceptual Framework. The findings
indicate that social influence, IT innovativeness, and attitudes significantly and positively impact consumers' behavioral
intentions toward mobile banking. However, performance expectancy, effect expectancy, environmental benefits, and privacy
concerns do not exhibit significant direct effects. Notably, attitudes play a mediating role, fully mediating the impact of
performance expectancy and partially mediating the influence of environmental benefits. The proposed model explains
70.32% of the variance in behavioral intentions, demonstrating a strong predictive ability and theoretical contribution. Thes e
insights provide valuable implications for financial institutions, policymakers, and technology developers seeking to improve
mobile banking adoption. By addressing key drivers and barriers, targeted strategies can be developed to enhance user
acceptance, trust, and engagement, ultimately fostering greater financial inclusion and digital transformation in Sri Lanka
Sympathetic Block for Treating Primary Erythromelalgia
Primary erythromelalgia is a rare condition that's characterized by erythema, an increased skin temperature and burning pain in the extremities. The pain is often very severe, and treating erythromelalgia is frustrating and difficult. We report here on the case of a 12-year old girl with primary erythromelalgia in both lower extremities. The pain was refractory to medical treatment, but a bilateral sympathetic block with lidocaine and triamcinolone resulted in relief from the pain. Our experience with this disease demonstrates that sympathetic blocks are effective in improving the symptoms and they may be attempted on erythromelalgia patients who do not respond to other treatments, including medication and epidural blocks
Impact on and use of an inner-city London Infectious Diseases Department by international migrants: a questionnaire survey
<p>Abstract</p> <p>Background</p> <p>The UK has witnessed a considerable increase in immigration in the past decade. Migrant may face barriers to accessing appropriate health care on arrival and the current focus on screening certain migrants for tuberculosis on arrival is considered inadequate. We assessed the implications for an inner-city London Infectious Diseases Department in a high migrant area.</p> <p>Methods</p> <p>We administered an anonymous 20-point questionnaire survey to all admitted patients during a 6 week period. Questions related to sociodemographic characteristics and clinical presentation. Analysis was by migration status (UK born <it>vs </it>overseas born).</p> <p>Results</p> <p>111 of 133 patients completed the survey (response rate 83.4%). 58 (52.2%) were born in the UK; 53 (47.7%) of the cohort were overseas born. Overseas-born were over-represented in comparison to Census data for this survey site (47.7% <it>vs </it>33.6%; proportional difference 0.142 [95% CI 0.049–0.235]; p = 0.002): overseas born reported 33 different countries of birth, most (73.6%) of whom arrived in the UK pre-1975 and self-reported their nationality as British. A smaller number (26.4%) were new migrants to the UK (≤10 years), mostly refugees/asylum seekers. Overseas-born patients presented with a broad range and more severe spectrum of infections, differing from the UK-born population, resulting in two deaths in this group only. Presentation with a primary infection was associated with refugee/asylum status (n = 8; OR 6.35 [95% CI 1.28–31.50]; p = 0.023), being a new migrant (12; 10.62 [2.24–50.23]; p = 0.003), and being overseas born (31; 3.69 [1.67–8.18]; p = 0.001). Not having registered with a primary-care physician was associated with being overseas born, being a refugee/asylum seeker, being a new migrant, not having English as a first language, and being in the UK for ≤5 years. No significant differences were found between groups in terms of duration of illness prior to presentation or duration of hospitalisation (mean 11.74 days [SD 12.69]).</p> <p>Conclusion</p> <p>Migrants presented with a range of more severe infections, which suggests they face barriers to accessing appropriate health care and screening both on arrival and once settled through primary care services. A more organised and holistic approach to migrant health care is required.</p
AAV-mediated photoreceptor transduction of the pig cone-enriched retina
Recent success in clinical trials supports the use of adeno-associated viral (AAV) vectors for gene therapy of retinal diseases caused by defects in the retinal pigment epithelium (RPE). In contrast, evidence of the efficacy of AAV-mediated gene transfer to retinal photoreceptors, the major site of inherited retinal diseases, is less robust. In addition, although AAV-mediated RPE transduction appears efficient, independently of the serotype used and species treated, AAV-mediated photoreceptor gene transfer has not been systematically investigated thus so far in large animal models, which also may allow identifying relevant species-specific differences in AAV-mediated retinal transduction. In the present study, we used the porcine retina, which has a high cone/rod ratio. This feature allows to properly evaluate both cone and rod photoreceptors transduction and compare the transduction characteristics of AAV2/5 and 2/8, the two most efficient AAV vector serotypes for photoreceptor targeting. Here we show that AAV2/5 and 2/8 transduces both RPE and photoreceptors. AAV2/8 infects and transduces photoreceptor more efficiently than AAV2/5, similarly to what we have observed in the murine retina. The use of the photoreceptor-specific rhodopsin promoter restricts transgene expression to porcine rods and cones, and results in photoreceptor transduction levels similar to those obtained with the ubiquitous promoters tested. Finally, immunological, toxicological and biodistribution studies support the safety of AAV subretinal administration to the large porcine retina. The data presented here on AAV-mediated transduction of the cone-enriched porcine retina may affect the development of gene-based therapies for rare and common severe photoreceptor diseases
Gene therapy for retinitis pigmentosa and Leber congenital amaurosis caused by defects in AIPL1: effective rescue of mouse models of partial and complete Aipl1 deficiency using AAV2/2 and AAV2/8 vectors
Defects in the photoreceptor-specific gene encoding aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) are clinically heterogeneous and present as Leber Congenital Amaurosis, the severest form of early-onset retinal dystrophy and milder forms of retinal dystrophies such as juvenile retinitis pigmentosa and dominant cone-rod dystrophy. [Perrault, I., Rozet, J.M., Gerber, S., Ghazi, I., Leowski, C., Ducroq, D., Souied, E., Dufier, J.L., Munnich, A. and Kaplan, J. (1999) Leber congenital amaurosis. Mol. Genet. Metab., 68, 200-208.] Although not yet fully elucidated, AIPL1 is likely to function as a specialized chaperone for rod phosphodiesterase (PDE). We evaluate whether AAV-mediated gene replacement therapy is able to improve photoreceptor function and survival in retinal degeneration associated with AIPL1 defects. We used two mouse models of AIPL1 deficiency simulating three different rates of photoreceptor degeneration. The Aipl1 hypomorphic (h/h) mouse has reduced Aipl1 levels and a relatively slow degeneration. Under light acceleration, the rate of degeneration in the Aipl1 h/h mouse is increased by 2-3-fold. The Aipl1-/- mouse has no functional Aipl1 and has a very rapid retinal degeneration. To treat the different rates of degeneration, two pseudotypes of recombinant adeno-associated virus (AAV) exhibiting different transduction kinetics are used for gene transfer. We demonstrate restoration of cellular function and preservation of photoreceptor cells and retinal function in Aipl1 h/h mice following gene replacement therapy using an AAV2/2 vector and in the light accelerated Aipl1 h/h model and Aipl1-/- mice using an AAV2/8 vector. We have thus established the potential of gene replacement therapy in varying rates of degeneration that reflect the clinical spectrum of disease. This is the first gene replacement study to report long-term rescue of a photoreceptor-specific defect and to demonstrate effective rescue of a rapid photoreceptor degeneration
- …
