MEMS Humidity Sensors

This chapter reviews MEMS humidity sensors fabricated using microfabrication technologies. It discusses the operation principle, different designs, and the fabrication technologies for the different sensing mechanisms. Sensing humidity using capacitive sensors is first reviewed with a highlight on the different sensing materials and how their permittivity and physical parameters affect the sensor performance. Then the chapter discusses the piezoelectric humidity sensing method, wherein piezoelectric sensors the dynamic mode measurement is used. In these sensors, the mass changes corresponding to the humidity, resulting in resonance frequency shift and amplitude change. Finally, the chapter reviews the resistive humidity sensors where the change in the resistivity of various materials is used as an indication of humidity change in the environment

Flipped classroom and psycholinguistic factors : an evaluation

Psycholinguistic factors, i.e., motivation, foreign language anxiety, and self-confidence, affect adult EFL learners’ learning process in a major way, positively or negatively. Research studies show that in a conventional classroom setup psycholinguistic factors affect the learning process of a large number of adult EFL learners negatively because their motivation and self-confidence are low while their foreign language anxiety is high. In the present research study, a survey was conducted with pre-university students in Saudi Arabia who were taught English as a foreign language using Flipped Classroom Model (FCM) as a pedagogy approach. The objective of this investigation was to measure the degree of impact of psycholinguistic factors on the language learning process of students learning English through an unconventional pedagogic approach, that is, Flipped Classroom Model. The results indicate that the teaching approach, even if being highly learner-centred, hardly makes any significant difference to learners’ anxiety, motivation, or self-confidence as regards learning English as a foreign language. However, in comparison to the conventional classroom environment, a slightly less number of learners reported the influence of affective factors on their English learning process under the FCM approach

Health Benefits and Biological Activity of Ginger Phytochemicals Against Chronic Diseases and Cancers

As cancer prevalence escalates significantly across the globe, fighting this terminal illness using phytochemicals is considered a green anticancer therapeutic approach. Many plants contain useful bioactive compounds that can influence cancer remedies positively. Moreover, these bioactive compounds derived from natural sources exhibited great vital contribution activities such as antioxidant, anti-inflammatory, and antimicrobial. Since antiquity, ginger was used in folk medicine as a reason for its ability to relieve systemic pain and food flavoring. Along with recent findings and discoveries, ginger and its derived phenolic compounds such as 6-gingerol, 8-gingerol, and 10-gingerol, shogaol, parasols, zingerone, and α-curcumene, each independently or collectively is well known to contribute prospectively in an accessible way in many chronic conditions such as obesity, diabetes, non-alcoholic fatty liver disease, Alzheimer disease, rheumatoid arthritis, asthma, and chronic kidney disease. On the other hand, drug-based ginger\u27s pharmacological properties show significant suppression of specific cancers such as skin, colorectal, pancreatic, prostate, breast, lung, AML, gastric, and HCC through series of distinctive mechanisms. It is notably now that these ginger characteristics, along with its beneficial flavonoid contents, are a novel therapeutic approach in a variety of ailments. &nbsp

Recent Advancements in GaN LED Technology

Gallium nitride (GaN)-based solid state lighting technology has revolutionized the semiconductor industry. The GaN technology has played a crucial role in reducing world energy demand as well as reducing the carbon footprint. As per the reports, the global demand for lighting has reduced around 13% of total energy consumption in 2018. The Department of Energy (USA) has estimated that bright white LED source could reduce their energy consumption for lighting by 29% by 2025. Most of the GaN LEDs are grown in c-direction, and this direction gives high growth rate and good crystal integrity. On the other hand, the c-plane growth induces piezoelectric polarization, which reduces the overall efficiency of LEDs since the last decade researchers round the globe working on III-N material to improve the existing technology and to push the limit of III-V domain. Now, the non-polar and semi-polar grown LEDs are under investigation for improved efficiency. With the recent development, the GaN is not only limited to lighting, but latest innovations also led the development of micro-LEDs, lasers projection and point source. These developments have pushed GaN into the realm of display technology. The miniaturization of the GaN-based micro-LED and integration of GaN on silicon driving the application into fast response photonic integrated circuits (ICs). Most of the recent advancements in GaN LED field would be discussed in detail

Surface-micromachined capacitive accelerometers in above-IC integration methods

This thesis proposes a methodology to optimize the design of capacitive accelerometers. This is achieved through a systematic improvement procedure of the closing-gaps accelerometers design. This is used to find the optimum electrode dimensions that would result in the highest sensitivity, within a specified area. The method is verified through the simulation and fabrication of different variations of two designs, then comparing the results with the expected values from analytical optimization methods. The prototypes are fabricated in a commercial process, which imposed limitations on the sizes of the possible accelerometer designs. A survey of prior published works shows the importance of the optimization technique suggested here to increase the performance of these types of sensors, when no fabrication restrictions exist.The thesis also introduces a novel low cross-sensitivity dual-axis capacitive accelerometer design. The device is fabricated in a silicon-on-insulator (SOI) process and its fabrication is finalized by an in-house release step. The device measures 1 mm × 1 mm, with four (4) proof masses that are able to sense accelerations in the X- and Y-axes independently. Two commercial capacitance-to-digital converters are used to read the outputs of both axes of the device in a system in package implementation. The fabricated device exhibits a sensitivity of 16.83 fF/g, while keeping the measured cross-sensitivity to less than 1 % throughout the ±4 g linear range. The rotational motion and Z accelerations have no impact on the device X and Y readings, thanks to the device's particular geometry and differential nature.In addition, the thesis presents a novel design of a 3D high-sensitivity lateral capacitive accelerometer. The accelerometer design utilizes the whole area of the sensor for both the sensing and proof masses, which cancels the tradeoff needed in conventional 2D designs. The design model of the accelerometer is developed to target the highest possible performance. A Z-shaped innovative design of the supporting beams is developed to limit the vertical displacement within the used submicron gap. The accelerometer measures 500 × 500 μm2 and achieves 58 fF/g sensitivity in a ±4 g range in an open-loop system. Suggestions are provided to decrease the 1.4 mg noise floor of the device.Finally, the thesis describes a 3D surface micromachining platform process for above-IC integration. This method uses non-conductive materials with attractive mechanical properties to fabricate micro-electromechanical systems (MEMS) devices. The fixed structures are created using a polyimide layer, while the moving structures are built using silicon nitride (SiN). A 240-nm thin parylene-N polymer layer is used as a sacrificial layer to largely define the capacitive gaps and enable dry release. The photolithography steps are limited to four, in order to ensure a simple and low-cost process. The process has a thermal budget of 300 °C, which should be safe for processing above CMOS integrated circuits. While the used materials provide good results, this process is not limited to these specific materials, and others can be used if needed.Cette thèse propose une méthode pour optimiser la conception des accéléromètre capacitifs avec un interstice pouvant se fermer. La méthode peut être utilisée pour trouver les dimensions optimales qui permettent une sensibilité maximale dans une zone spécifiée. La méthode est vérifiée en simulant et en fabriquant différentes variantes de deux dispositifs et en comparant les résultats avec les valeurs obtenues de la méthode d'optimisation analytique. Les variations sont fabriquées dans un processus commercial, ce qui limite le nombre et la taille des dispositifs testés. Une revue des travaux publiés montre l'importance de l'optimisation pour augmenter les performances de ces dispositifs dans le cas où aucune restriction de fabrication n'existe.La thèse présente également un nouveau concept d'accéléromètre capacitif à double axe et à faible sensibilité croisée. Le dispositif est fabriqué dans un procédé d'oxyde sur silicium (SOI) et sa fabrication est finalisée par une étape de relâche dans nos laboratoires. Le dispositif mesure 1 mm x 1 mm et a quatre masses capables de détecter les accélérations dans les axes X et Y indépendamment. Deux convertisseurs de capacité numériques commerciaux sont utilisés pour lire les sorties des deux axes du dispositif dans un système mis en boitier. Le dispositif fabriqué présente une sensibilité de 16,83 fF / g tout en maintenant la sensibilité croisée mesurée à moins de 1% dans la gamme linéaire de ± 4 g. Le mouvement de rotation et les accélérations en Z n'ont aucun impact sur les lectures en X et en Y du dispositif. Cela est possible grâce à la géométrie particulière et à la nature différentielle de l'appareil.De plus, la thèse présente un nouveau concept d'un accéléromètre capacitif latéral à haute sensibilité avec électrodes 3D. La conception de l'accéléromètre utilise toute la surface du capteur pour la détection du mouvement de la masse, ce qui mitige le compromis typiquement nécessaire dans les dispositifs 2D. L'accéléromètre est développé pour cibler les performances les plus élevées possibles. Un design innovant en forme de Z des supports mécaniques est développé pour limiter le déplacement vertical dans l'interstice submicronique utilisé. L'accéléromètre mesure 500 × 500 μm2 et atteint 58 fF / g de sensibilité dans une gamme ±4 g dans un système de mesure à boucle ouverte. Des solutions sont suggérées pour diminuer le bruit de fond de 1,4 mg de l'appareil de mesure.Finalement, la thèse décrit un processus de plate-forme de microfabrication en surface 3D pour intégration sur circuits intégrés. Cette méthode utilise des matériaux non conducteurs avec des propriétés mécaniques attrayantes pour la construction de dispositifs MEMS. Les plates-formes fixes sont créées à l'aide d'une couche de polyimide, tandis que la structure mobile est faite en nitrure de silicium. Une couche de parylène-N de 240 nm d'épaisseur est utilisée comme couche sacrificielle pour définir l'interstice capacitif et pour permettre la relâche à sec. Les étapes de photolithographie sont limitées à quatre pour assurer un processus simple. Le procédé a un budget thermique de 300 ° C, ce qui est adéquat pour l'intégration du procédé sur circuits intégrés. Bien que les matériaux utilisés fournissent de bon résultats, ce processus n'est pas limité à ceux-ci et d'autres matériaux peuvent être utilisés si nécessaire

Antimycobacterial and Anticancer Properties of <i>Myrtus communis</i> Leaf Extract

Background: Plant-derived products or extracts are widely used in folk/traditional medicine to treat several infections, ailments, or disorders. A well-known medicinal herb, Myrtus communis is an evergreen fragrant plant native to the Mediterranean region that has been used for ages in traditional medicine around the world. Materials and methods: The microplate alamarBlue assay and the well diffusion method were used to evaluate the zone of inhibition and MIC, respectively. The double-disc diffusion method was used to investigate the synergy between antibiotics and the extract. The crystal violet method was used to investigate biofilm development. The SulphoRhodamine-B assay and DNA flow cytometry were used to investigate the proliferation and subsequent distribution of cells among different phases of the cell cycle. The apoptotic and necrotic phases of the cancer cells were examined using flow cytometry in conjunction with Annexin V-FITC/PI labeling. Using the IBM SPSS statistical program, a one-way ANOVA with Tukey’s post hoc test was employed for statistical analysis. Results: The ethanolic leaf extract of M. communis showed a strong growth inhibition effect (zone of inhibition: 20.3 ± 1.1–26.3 ± 2.5 mm, MIC: 4.88–312.5 µg/mL, and MBC: 39.07–1250 μg/mL) against several rapidly growing and slow-growing mycobacterial strains in a dose-dependent manner. Damage to the cell wall of bacterial cells was determined to be the cause of the antimycobacterial action. The extract inhibited biofilm formation (MBIC of 9.7 µg/mL) and eradicated already-formed mature and ultra-mature biofilms of M. smegmatis, with MBEC values of 78 µg/mL and 156 µg/mL, respectively. Additionally, the extract exhibited potent anticancer effects against diverse cancer cell lines of the breast (MCF-7), liver (HepG2), cervix (HeLa), and colon (HCT116) (IC50 for HCT116: 83 ± 2.5, HepG2: 53.3 ± 0.6, MCF-7: 41.5 ± 0.6, and HeLa: 33.3 ± 3.6) by apoptosis after arresting the cells in the G1 phase of the cell cycle. Conclusions: These results suggest that M. communis leaf extract is a potential source of secondary metabolites that could be further developed as potential anticancer and antimycobacterial agents to treat diverse types of cancers and mycobacterial infections

Computational study and in vitro evaluation of the anti-proliferative activity of novel naproxen derivatives

In the present work, five naproxen derivatives, i.e., 3-amino-(4E)-5-imino-1-[2-(6-methoxy-2-naphthyl)propanoyl]-4-(benzylidene)-4,5-dihydro-1H-pyrazole (a), 3-amino-(4E)-5-imino-1-[2-(6-methoxy-2-naphthyl)propanoyl]-4-(4-bromobenzylidene)-4,5-dihydro-1H-pyrazole (b), 3-amino-(4E)-5-imino-1-[2-(6-methoxy-2-naphthyl)-propanoyl]-4-(4-methoxybenzylidene)-4,5-dihydro-1H-pyrazole (c), 3-amino-(4E)-5-imino-1-[2-(6-methoxy-2-naphthyl)propanoyl]-4-(4-methylbenzylidene)-4,5-dihydro-1H-pyrazole (d), 3-amino-(4E)-5-imino-1-[2-(6-methoxy-2-naphthyl)propanoyl]-4-(4-nitrobenzylidene)-4,5-dihydro-1H-pyrazole (e) were synthesized then characterized by FTIR, 1H and 13C NMR techniques. The ground state geometries were optimized by B3LYP functional of density functional theory (DFT) with three different basis sets (6-31G∗, 6-31G∗∗ and 6-31+G∗∗). The absorption wavelengths, oscillator strengths and major transitions were calculated using time dependent DFT. The effect of electron withdrawing groups (–NO2 and –Br) and electron donating groups (–CH3 and –OCH3) was intensively studied with respect to structure–activity relationship (SAR), quantitative structure–activity relationship (QSAR), frontier molecular orbitals (FMOs), molecular electrostatic potentials (MEP) and global reactivity descriptors. By the analysis of molecular docking work, it was found that pure hydrophobic substitution at position 4 of aldehyde part is more favorable than hydrophilic one. Compound c showed strong anti-proliferative activity against MCF-7 cells with IC50 value of 1.49 μM, and compound d showed moderate activity. The docking studies revealed that normal alkane chain is improving the biological activity in compound c, which endorsed to bury well in the active site resulting to enhance the hydrophobic interactions. The newly synthesized compounds against tested cell lines showed stronger antiproliferative activity as compared to the naproxen

The knowledge regarding the impacts and management of black triangles among dental professionals and laypeople

Abstract This study aimed to assess the knowledge regarding impacts, causes and management of black triangles (BT) among participants from different educational backgrounds including dental students, dentists and laypeople. This descriptive cross-sectional observational research included 435 participants who comprised 4 groups: pre-clinical (3rd year) dental students, clinical (4th and 5th year) dental students, dentists, and laypeople. A constructed self-reported questionnaire was utilized to assess participants’ demographic data and their knowledge of the impacts, causes and management of BT. The VAS scale was used to assess participants’ ratings for the impacts of BT on esthetics, with 0 meaning no impact and 10 meaning very severe negative impacts. The most reported treatments for BT were “cannot be treated” 99.3% and “non-surgical periodontal treatment” 67.1%. Meanwhile, the least reported was “modify the porcelain” 41.8%. The most reported cause of BT was “periodontal disease” 85.1%. However, the least reported were “parafunction” and “deep implants” 33.1% each. Dental professionals had better knowledge of the causes (t = 8.189, P < 0.001) and management (t = 8.289, P < 0.001) of BT than the non-dental participants. The dentists had the best knowledge, while the laypeople had the least knowledge of the causes (F = 62.056, P < 0.001) and treatment (F = 46.120, P < 0.001) of BT. The knowledge of the causes (t = 0.616, P = 0.538) and treatment (t = 1.113, P = 0.266) for BT was not significantly different between males and females. Age was not significantly related to the total knowledge about the causes (r = −0.034, P = 0.475) or treatment (r = −0.034, P = 0.482) for BT. Dental professionals had better knowledge of the impacts, causes and management of BT than the non-dental participants. The dentists were the best, while the laypeople were the worst in this regard. Age and gender had no relationships with the knowledge of causes or management of BT