Photonic hydrogel sensors

Hydrogels are an important tools for sensing because of their sensitivity to small adjustments and reactions to physical, biological, and chemical changes. They have been used in wide range of applications such as biomedical fields for drug delivery and in diagnostics. Hydrogel-based systems are a reusable sensing platform to quantify biomarkers in high-risk patients at clinical and point-of-care settings. In this thesis, two fabrication methods have been developed to successfully detect glucose concentration, pH changes and intraocular pressure (IOP). Continuous glucose monitoring aims to achieve accurate control of blood glucose concentration to prevent hypo/hyperglycaemia in diabetic patients. Also, the development of pH changes sensing device is the key to prevent the fatal implications. The Increasing of intraocular pressure (IOP) is the main risk factor for glaucoma, which is the second major source of losing sight in the world. The first method is to developed hydrogel-based sensor by using stamping technique. A novel glucose sensor based on hydrogel with a micro-imprinted hexagonal structure was fabricated here. Our method utilized diffraction properties of a hexagonally photonic microscale concavities to detect the changes in the glucose concentration from 1 mM to 200 mM. In addition, same method was used to design a new pH hydrogel-based sensor with imprinted Fresnel lens. The sensor was able to monitor the pH changes with respond time of 5 minutes. The sensor had pH range from 4.5 to 7 and showed an increase in the sensitivity after 10 days storage in PBS solution of pH 7.4. Also, when the effect of temperature changes was investigated in the study, the temperature effect was negligible in the performance the sensor. The second method is Laser ablation of commercial contact lenses. Initially, CO2 laser (HPC LS 3040) was used to modify the surface properties of the lens at selective areas by creating 1D and 2D patterns. Laser parameters (space gap between the patterns and laser power, and scan speed) were examined to find the optimal laser setting. We managed to improve the wettability properties of the lens by increasing the density of the surface. After that, we engraved two circular micro-channels on the contact lens using CO2 laser (Rayjet laser). Three different lenses were fabricated with various spacing gap between the channels (1 mm, 1.5 mm and 2 mm). The lenses had maximum channel depth of up to 20 µm. By using laser treated lenses, a change in pressure from 12 mmHg to 22 mmHg, normal eye IOP and glaucoma patients IOP, was detect by the lenses. In summary, this thesis presents important findings that can be recommended for application in medical point-of-care diagnostics, implantable chips, and wearable continuous monitoring devices to quantify biomarkers. These methods offer sensing devices that are easy and fast to manufacture, cost effective, fast response and noninvasive sensors

Is Taha Abdurrahman a Contractarian Philosopher?

This study aimed to examine the possibility of considering the contemporary Moroccan philosopher Taha Abdurrahman-who has the possibility of being "The Next Big Thing" in Islamic philosophy-a part of the contractarian tradition. The overall objective of this can be summarized in two points: The first is to determine whether Taha's theory is essentially contractarian, in which case contractarian critique would apply to it. The second is to assess the implications of his "contract/ covenant" theory in terms of present and future ethical and political studies. In order to do this, the major themes of contractarian philosophy had been examined through a brief historical study, in which the study did not seek a "single unbroken tradition of contractarianism", but for different traits of what was called contractarian through the ages. which gave us the opportunity to extract the main characteristic of a "contractarian theory." In this thematic study, three general themes of contractarianism were adopted from previous studies: ethical/ moral, civil, and constitutional. Through these themes, the most influential accounts of contractarianism were examined to identify what makes a "contractarian theory.

Contact lens-based microchannel rings for detecting ocular hypertension

Glaucoma is a major cause of irreversible blindness worldwide. The most acknowledged biomarker to diagnose and monitor glaucoma progression is intraocular pressure (IOP). Gold standard techniques for IOP monitoring are invasive, uncomfortable, and require visiting a clinic. In addition, most methods only provide a single snapshot on widely varying parameters. On the other hand, contact lenses have attracted particular interest to be used as continuous monitoring platforms to incorporate sensors, drugs, and more. Here, commercial contact lenses were laser-processed to be capable of detecting IOP variations in the physiological range. Three ring-couples with interspaces of 1.0, 1.5, and 2.0 mm were engraved on three soft contact lenses separately by using a carbon dioxide laser. The IOP/pressure variations induced repeatable changes in the ring-couple interspace which acted as a smartphone-readable pressure sensor. The processed contact lenses may be a potential candidate toward IOP monitoring at point-of-care settings

Optical glucose sensors based on hexagonally-packed 2.5-dimensional photonic concavities imprinted in phenylboronic acid functionalized hydrogel films

Continuous glucose monitoring aims to achieve accurate control of blood glucose concentration to prevent hypo/hyperglycaemia in diabetic patients. Hydrogel-based systems have emerged as a reusable sensing platform to quantify biomarkers in high-risk patients at clinical and point-of-care settings. The capability to integrate hydrogel-based systems with optical transducers will provide quantitative and colorimetric measurements via spectrophotometric analyses of biomarkers. Here, we created an imprinting method to rapidly produce 2.5D photonic concavities in phenylboronic acid functionalized hydrogel films. Our method exploited diffraction properties of hexagonally-packed 2.5D photonic microscale concavities having a lattice spacing of 3.3 μm. Illumination of the 2.5D hexagonally-packed structure with a monochromatic light source in transmission mode allowed reversible and quantitative measurements of variation in the glucose concentration based on first order lattice interspace tracking. Reversible covalent phenylboronic acid coupling with cis-diols of glucose molecules expanded the hydrogel matrix by ∼2% and 34% in the presence of glucose concentrations of 1 mM and 200 mM, respectively. A Donnan osmotic pressure induced volumetric expansion of the hydrogel matrix due to increasing glucose concentrations (1–200 mM), resulted in a nanoscale modulation of the lattice interspace, and shifted the diffraction angle (∼45° to 36°) as well as the interspacing between the 1st order diffraction spots (∼8 to 3 mm). The sensor exhibited a maximum lattice spacing diffraction shift within a response time of 15 min in a reversible manner. The developed 2.5D photonic sensors may have application in medical point-of-care diagnostics, implantable chips, and wearable continuous glucose monitoring devices

Overview on Epidemiology and Management of Myxedema Coma or Crisis

The most severe type of hypothyroidism is known as myxedema coma, which can quickly lead to death if not identified and treated aggressively. The condition known as hypothyroidism is easily detected and treated. But if ignored, it might eventually progress to myxedema coma, the most serious form of hypothyroidism. Since the majority of patients do not initially appear in a coma, the term "myxedema coma" is usually regarded as misleading. Lethargy usually progresses to stupor, which then becomes a coma with hypothermia and respiratory failure. only clinical criteria are used for diagnosis because thyroid hormone assays are unable to distinguish between simple hyperthyroidism and thyroid storm. Apart from essential medical interventions, the treatment focuses on preventing thyroid hormone production and secretion as antithyroid medications, and preventing the peripheral effects of thyroid hormone as β-blocker, glucocorticoids. The diagnosis of thyroid-stimulating hormone (TSH) in the blood is the same as that of simple hypothyroidism. As soon as a diagnosis is obtained, treatment should start right away. The majority of hospital and commercial laboratories can turnaround a TSH test in a matter of hours

Effect of nocturnal hypoxemia on glycemic control among diabetic Saudi patients presenting with obstructive sleep apnea

BackgroundObstructive sleep apnea (OSA) is a prevalent disease that is associated with an increased incidence of type II diabetes mellitus (DM) if left untreated. We aimed to determine the association between glycosylated hemoglobin (HbA1c) levels and both nocturnal hypoxemia and apnea-hypopnea index (AHI) among a Saudi patients with OSA.MethodsA cross-sectional study that enrolled 103 adult patients diagnosed with DM and confirmed to have OSA by full night attended polysomnography between 2018 and 2021. Those who presented with acute illness, chronic obstructive pulmonary disease (COPD)/restrictive lung diseases causing sleep-related hypoxemia, or no available HbA1c level within 6 months before polysomnography were excluded from the study. Univariate and multivariate linear regression analyses between HbA1c levels and parameters of interest were tested.ResultsSixty-seven (65%) of the studied population had uncontrolled DM (HbA1c ≥7%). In univariate regression analysis, there was a significant positive association between HbA1c, and sleep time spent with an oxygen saturation below 90% (T90), female gender, and body mass index (BMI) (p<0.05) but not AHI, or associated comorbidities (p>0.05). In the multivariate analysis, HbA1c was positively associated with increasing T90 (p<0.05), and ODI (p<0.05), but not with AHI (p>0.05).ConclusionNocturnal hypoxemia could be an important factor affecting glycemic control in patients with OSA suffering from DM irrespective of the severity of both diseases

عن نظرية السلطة في الإسلام : دراسة في مفهوم السلطة السياسية ومصادرها والقيود الواردة عليها في الفكر الإسلامي

علم النظرية السياسية من العلوم التي لم تنل ذلك القسط الوافي من البحث داخل مجال العلوم السياسية - وخاصة في ما يتعلق بالتراث الإسلامي - من المختصين في المجالين معاً ( الفقه والعلوم السياسية ) ، فهناك الكثير من الدارسات السياسية المحضة حول هذا الموضوع وهناك الكثير من الدراسات الفقهية التأصيلية ، لكن الصورة لا تتضح دون بناء نموذج يعتمد على كل المنهجين ، إذ إنها – أي النظرية السياسية الإسلامية – مبنية عليهما معاً . وهذا الكتاب هو مقاربة بحثية أصلها رسالة ماجستير في مجال النظرية السياسية نحاول من خلالها استيعاب السياق التاريخي لنشوء أو تبلور مفهوم السلطة السياسية داخل السياق الإسلامي من خلال الرجوع لعصر التكوين ، وسنمر في الكتاب على تطور المفهوم وتوابعه في الحضارة الغربية من اليونان وحتى مجموعة العقد الاجتماعي تاركين العصور الحديثة في كلا السياقين الأوروبي والإسلامي لدراسة أخرى . ثم ننتقل لبحث مصادر تلك السلطة مفرقين في هذا السياق بين السلطة من حيث هي قدرة على الإجبار والقهر ، والسلطة ذات الأحقية فيما اصطلح على تسميته لاحقاً بالشرعية . ونختم بالكلام عن القيود الواردة على السلطة السياسية ومصادر تلك القيود وطبيعتها بشكل مختصر . اتنبع أهمية الكلام عن هذا الموضوع في ذلك العصر من شرعية الخلفاء الأربعة في الفكر السياسي الإسلامي ، من حيث كون السلوك السياسي الصادر عنهم أو تحت علمهم يعتبر جزءً لا يتجزء من المنظومة السياسية التي أثرت وما زالت تؤثر على الدول التي تتبع هذا النوع من الفكر أو السلوك ، وآمل أن يكون هذا البحث خطوة على طريق تحديد معالم النظرية السياسية العامة للفكر الإسلامي في ظل هذه الأجواء المشحونة في الدول العربية والإسلامية والعالم أجمع

Methods for assessing sleep and sleepiness in healthy adults and patients with respiratory sleep disorders

Scalp electroencephalography (scalp EEG) is an accurate method for measuring sleep. However, this procedure is cumbersome, costly, and cannot be conducted over an extended period. Recently, wearable pieces of equipment to monitor sleep have been developed, one of which is the in-ear EEG. Therefore, the first two aims of this thesis were to investigate whether a novel in-ear EEG could measure sleep accurately during daytime naps, and then during overnight sleep. Clinically, excessive daytime sleepiness (EDS) is usually measured subjectively by use of the Epworth sleepiness scale (ESS). However, patients sometimes make errors and require assistance when they complete the ESS. A visual analogue scale (VAS) is a simple method that is used to measure subjective feelings such as pain, mood and breathlessness; we hypothesised that it could also measure sleepiness. Therefore, the third aim of this thesis was to investigate whether the VAS could be used as an accurate method to measure sleepiness in patients with respiratory sleep disorders, and in healthy adults. In the first study, the in-ear EEG detected sleep onset and the results offered substantial agreement with the findings of scalp EEG, in healthy adults during daytime naps. In the second study, the in-ear EEG detected slow-wave sleep at a substantial level of agreement compared with scalp EEG, in healthy adults during overnight sleep. In the third study, the VAS detected sleepiness in healthy adults and patients with respiratory sleep disorders, before and after one month of continuous positive airway pressure (CPAP) treatment. In summary, this thesis has shown that the in-ear EEG and VAS offer accurate and simple methods for the measurement of sleep and sleepiness, in both patients and healthy participants. In future, it is speculated that these two methods could be integrated into smart phones to offer simple, fast and accurate measurement of sleep and sleepiness.Open Acces

Optical hydrogel detector for pH measurements

Measuring pH has become a major key for determining health conditions, and food safety. The traditional pH assessment approaches are costly and offer low sensitivity. Here, a novel pH sensor based on a pH-responsive hydrogel has been developed. A Fresnel lens pattern was replicated on the surface of the pH-responsive hydrogel using the replica mould method. The pH sensors were tested in a pH range of 4–7. Introducing various pH solutions to the pH sensor led to volumetric shifts as the hydrogel swelled with pH. Consequently, the dimensions of the replicated Fresnel lens changed, modifying the focal length and the focus efficiency of the optical sensor. As a result, the measured optical power at a fixed distance from the sensor changed with pH. The optical sensor showed the best performance in the acidic region when pH changed from 4.5 to 5.5, in which the recorded power increased by 13%. The sensor exhibited high sensitivity to pH changes with a short respond time in a reversible manner. The developed pH optical sensor may have applications in medical point-of-care diagnostics and wearable continuous pH detection devices

Antioxidant Activity of <i>Moringa oleifera</i> and Olive <i>Olea europaea</i> L. Leaf Powders and Extracts on Quality and Oxidation Stability of Chicken Burgers

Oxidation is the main cause of quality deterioration in meat-based foods, such as burgers. Antioxidants inhibit the oxidation process; recently, natural antioxidants have gained interest, due to safety concerns. In this study, the effects of leaf powder and crude extracts of both Moringa oleifera and olive in chicken burgers were studied for their antioxidant potential in preventing fat oxidation during storage. Antioxidant activities were evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl). The results showed the highest DPPH radical scavenging with IC50 values of 2.397 ± 0.10 mg/mL in the Moringa leaf. Total phenolic content (TPC) was crude olive extract > crude Moringa extract > olive leaf > Moringa leaf. The total flavonoid content (TFC) was significantly higher in the olive leaf and its crude extract than in the Moringa leaf and its crude extract. The pH, total volatile nitrogen, and sensory properties were affected by the addition of olive and Moringa (leaf and crude extracts) to chicken burgers refrigerated for 20 days. The addition of Moringa and olive leaf powder decreased lipid oxidation and PV after 10 days of storage. In general, Moringa and olive leaf treatments slowed the deterioration of meat, suggesting their use as preservatives to extend the shelf-life of chicken burgers