Structure type and disorder have become important questions in catalyst design, with the most active catalysts often noted to be “disordered” or “amorphous” in nature. To quantify the effects of disorder and structure type systematically, a test set of manganese(III,IV) oxides was developed and their reactivity as oxidants and catalysts tested against three substrates: methylene blue, hydrogen peroxide, and water. We find that disorder destabilizes the materialsthermodynamically, making them stronger chemical oxidantsbut not necessarily better catalysts. For the disproportionation of H2O2 and the oxidative decomposition of methylene blue, MnOx-mediated direct oxidation competes with catalytically mediated oxidation, making the most disordered materials the worst catalysts, whereas for water oxidation, the most disordered materials and the strongest chemical oxidants are also the best catalysts. Even though the manganese(III,IV) oxide materials were able to oxidize both methylene blue and peroxides directly,the same materials were able to act as catalysts for the oxidation of methylene blue in the presence of peroxides. This impliesthat effects of electron transfer time scales are important and strongly affected by structure type and disorder. This is discussed In the context of catalyst design.
Background: In capturing a negative image, the digital impression secures a digital record for the purposeof designing and creating restorations. The introduction of scanning system presents a paradigm shift in the way of the dental impression procedure and encourages the accuracy of obtained restoration especially in the marginal area as a result of producing accurate final impression The digital system offers many advantages over the Conventional method.. The objective of this present in vitro study was to evaluate the marginal fitness of all ceramic crowns fabricated by direct digital scanning of the prepared tooth using two types of intra-oral cameras (Bluecam camera with strip light projection technique and Omnicam camera with video sa
... Show MoreDeriving land cover information from satellite data is one of the most common applications employed to monitor, evaluate, and manage the environment. This study aims to detect the land cover/land use changes and calculate the areas of different land cover types in Baghdad, Iraq, for the period from 2015 to 2020, using Landsat 8 images. The supervised Maximum Likelihood Classification (MLC) method was applied to classify the images. Four land cover types were obtained, namely urban, vegetation, water, and barren soil. Changes in the four land cover classes during the study period were observed. The extent of the urban, vegetation, and water areas was increased by about 7.5%, 9.5%, and 1.5%, respectively, whereas t
... Show MoreEffects of Boron on the structure of chloroplasts membrane isolated from cauliflower are investigated , using light scattering technique. Results obtained in this study suggest that Boron in the concentration range (0.1-5 µm) can fluidize the lipids of the chloroplast membrane due to different extent. Mechanisms by which Boron can change the lipid fluidity is discussed. Furthermore, an experimental evidence is presented to show that2µM Boron can mediate conformational changes in the membrane –bound proteins of the cauliflower’s chloroplast.
This paper proposes a new structure of the hybrid neural controller based on the identification model for nonlinear systems. The goal of this work is to employ the structure of the Modified Elman Neural Network (MENN) model into the NARMA-L2 structure instead of Multi-Layer Perceptron (MLP) model in order to construct a new hybrid neural structure that can be used as an identifier model and a nonlinear controller for the SISO linear or nonlinear systems. Weight parameters of the hybrid neural structure with its serial-parallel configuration are adapted by using the Back propagation learning algorithm. The ability of the proposed hybrid neural structure for nonlinear system has achieved a fast learning with minimum number
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Concentrated research topic in addressing variable vital to the work of offices of inspectors general, construction and scale effectiveness and efficiency is the organizational structure, which are important as is obvious to any researcher in the management and organization and this variable would affect the exercise task supervision and inspection of financial and administrative corruption and combat efficiently, Thus this effect will be placed in the fold ability to achieve goals. That the creation of the organizational structure and requirements to achieve harmony between its properties is creating step towards success. This research aims to analyze the characteristics and style o
Background:Incisional hernia is frequently occurring post operative complication after general surgery with occurance rate 2%-----11%,, it is either appear soon after operation or
late occurring incisional hernia..
Patient &methods: This is a prospective study that was conducted on 84 patients who were admitted at Baghdad Teaching Hospital during the period from Oct. 1999 to Aug. 2001 for
repair of incisional hernias. Their ages were ranging from 24-74 years with mean age of (48 ±12). Sixty-nine patients were elective and 15 patients were urgent. Assessment of the patients
for the predisposing factors influencing the development of incisional hernia was done and in our study these factors were: -
R
Background: The development of non steroidal anti-inflammatory drugs (NSAIDs) was based principally on inhibiting cyclooxygenases (COX) activity. However, the identification of two
COX- isoforms (i.e., COX-1 and COX-2) with different physiological effects has led to the development of COX-2 specific NSAIDs, with fewer adverse effects than traditional NSAIDs.
Therefore, They are expected to produce anti-inflammatory activity with minimal adverse effects on GI mucosa, as well as, other structures and cells such as platelets.
The aim of this study is to evaluate the effect of selectivity of COX-2 inhibitors on many organs and systems function such as the hepatobiliary system, platelets function, as well as, seru