Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.
Medicinal plants contain bioactive substances that are highly bioavailable in extracts or pure molecules, making them promising for therapeutic applications and precursors for chemo-pharmaceutical semi-synthesis. Harpagophytum procumbens (Devil’s Claw) is widely recognized as one of the most potent therapeutic herbs. This study aimed to extract seeds from H. procumbens using two types of solvents and to assess both qualitative and quantitative aspects of the extracts. The two extracts were evaluated for antibacterial and anti-biofilm activities using agar well diffusion assays against four bacterial isolates and two yeast isolates. Qualitative analysis identified the presence of alkaloids, flavonoids, tannins, saponins, and terpen
... Show MoreAbstract Inflammation of periodontal tissues is the consequence of interaction between periodontal pathogens and immune system. This is associated with increased expression of inflammatory cytokines, which may exert destructive effect to the periodontal tissues when released over long period. The aim of this study was to chronologically track the homeostasis of oral keratinocytes following removal of periodontal pathogens. This was done by investigating expression of selected inflammatory markers and integrity of epithelial monolayers in vitro. Rat oral keratinocytes were stimulated with heat-killed Fusobacterium nucleatum and Porphyromonas gingivalis over 7-days then bacteria were washed away and epithelial cells re-cultured for 3-
... Show MoreWith the increasing intensity of the ecological and environmental problems and the scarcity of fresh water, this paper was introduced to investigate the ability to use treated wastewater as a cooling media via studying its behavior throughout a cooling tower. The simultaneous transfer of heat and mass from the treated wastewater to air over splash-fill packing arranged in a zigzag manner was studied. The characteristic of the cooling tower, the outlet water temperature, and the rejected heat were investigated as the water-to-air ratio and inlet water temperature were varied. The core results show that the cooling tower of the tower decreases with increasing water-to-air ratio, and increases with the raise of inlet water temperature.
... Show MorePerceived Trust of Stakeholders: Predicting the Use of COBIT 2019 to Reduce Information Asymmetry
As cultures are mainly divided into collectivistic and individualistic, members tend to emphasize, through communication, either their position as part of their group or their independence from the group. This emphasis is manifested in using the pragmatic concepts of positive politeness and negative politeness. The present study looks into the reflection of these two cultures in Rockstar’s renowned video game, Red Dead Redemption 2 (2018). It aims at identifying the two cultures as present in the game and showing their significance to its narrative. It fills the gap in the studies of language used within video games as well as its cultural reflections. The study addresses the following question: What are the positive and negative
... Show MorePeak ground acceleration (PGA) is one of the critical factors that affect the determination of earthquake intensity. PGA is generally utilized to describe ground motion in a particular zone and is able to efficiently predict the parameters of site ground motion for the design of engineering structures. Therefore, novel models are developed to forecast PGA in the case of the Iraqi database, which utilizes the particle swarm optimization (PSO) approach. A data set of 187 historical ground-motion recordings in Iraq’s tectonic regions was used to build the explicit proposed models. The proposed PGA models relate to different seismic parameters, including the magnitude of the earthquake (Mw), average shear-wave velocity (VS30), focal depth (FD
... Show MoreA 3D geological model is an essential step to reveal reservoir heterogeneity and reservoir properties distribution. In the present study, a three-dimensional geological model for the Mishrif reservoir was built based on data obtained from seven wells and core data. The methodology includes building a 3D grid and populating it with petrophysical properties such as (facies, porosity, water saturation, and net to gross ratio). The structural model was built based on a base contour map obtained from 2D seismic interpretation along with well tops from seven wells. A simple grid method was used to build the structural framework with 234x278x91 grid cells in the X, Y, and Z directions, respectively, with lengths equal to 150 meters. The to
... Show MoreBackground: Acute appendicitis is a common surgical
problem that is associated with an acute-phase reaction.
Previous studies have shown that cytokines and acutephase proteins are activated and may serve as indicators for
appendicitis.
Objective: The aim of this study was to evaluate of serum
levels of interleukin-6 (IL-6) in correlation to the severity
to acute appendicitis.
Methods: This is a prospective study from December 2008
to March 2009 of patients who had appendectomy in
Department of Surgery, Al-Kindy Teaching Hospital -
Baghdad/Iraq. Serum for estimating levels of interleukin-6
(IL-6) was taken pre-operatively. Depending on the
macroscopic evidence during the operation and the
histopathol
A new Schiff base [I] was prepared by refluxing Amoxicillin trihydrate and 4-Hydroxy- 3,5-dimethoxybenzaldehyde in aqueous methanol solution using glacial acetic acid as a catalyst. The new 1,3-oxazepine derivative [II] was obtained by Diels- Alder reaction of Schiff base [I] with phthalic anhydride in dry benzene. The reaction of Schiff base [I] with thioglycolic acid in dry benzene led to the formation of thiazolidin-4-one derivative [III]. While the imidazolidin-4-one [IV] derivative was produced by reacting the mentioned Schiff base [I] with glycine and triethylamine in ethanol for 9 hrs. Tetrazole derivative [V] was synthesized by refluxing Schiff base [I] with sodium azide in dimethylformamid DMF. The structure of synthesized compound
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