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Structure and in silico simulations of a cold-active esterase reveals its prime cold-adaptation mechanism
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Here we determined the structure of a cold active family IV esterase (EstN7) cloned from Bacillus cohnii strain N1. EstN7 is a dimer with a classical α/β hydrolase fold. It has an acidic surface that is thought to play a role in cold-adaption by retaining solvation under changed water solvent entropy at lower temperatures. The conformation of the functionally important cap region is significantly different to EstN7's closest relatives, forming a bridge-like structure with reduced helical content providing greater access to the active site through more than one substrate access tunnel. However, dynamics do not appear to play a major role in cold adaption. Molecular dynamics at different temperatures, rigidity analysis, normal mode analysis and geometric simulations of motion confirm the flexibility of the cap region but suggest that the rest of the protein is largely rigid. Rigidity analysis indicates the distribution of hydrophobic tethers is appropriate to colder conditions, where the hydrophobic effect is weaker than in mesophilic conditions due to reduced water entropy. Thus, it is likely that increased substrate accessibility and tolerance to changes in water entropy are important for of EstN7's cold adaptation rather than changes in dynamics.

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Publication Date
Mon Oct 01 2012
Journal Name
Iraqi Journal Of Physics
Effects of copper doping and annealing on the structure and optical properties of ZnxCdx-1S thin films
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Effect of copper doping and thermal annealing on the structural and optical properties of Zn0.5Cd0.5S thin films prepared by chemical spray pyrolysis have been studied. Depositions were done at 250°C on glass substrate. The structural properties and surface morphology of deposited films were studied using X-ray diffraction (XRD) and photomicroscope (PHM) techniques. XRD studies reveal that all films are crystalline tetragonal structure. The film crystallinity are increased with 1% Cu-doping concentration and also increased for the films annealed at 300°C than the other studied cases. The lattice constant 'a' and 'c' varies with doping concentrations from 5.487Å to 5.427Å and 10.871Å to 10.757Å respectively. The grain size attained

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Publication Date
Sun Jul 04 2010
Journal Name
Journal Of The Faculty Of Medicine Baghdad
The Effect of Exposure to Formaldehyde Vapor on the Structure of Testes in the Rabbits.
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Background: This study has been performed to detect any structural changes in the testes of rabbits that have been exposed to formaldehyde vapor.
Materials and Methods: Eighteen male rabbits has been used in this study, 12 of them were exposed to formalin vapor for 2 month, while the other 6 were exposed to the vapor of distilled water for 2 month too. All animals were killed at the end of experiments, and then pieces of testes were prepared for light microscopic examination. Sections were collected from the paraffin wax blocks and stained by H & E and finally examined by Olympus light microscope.
Results: Most of the seminiferous tubules from the formaldehyde exposed group were atrophied with no e

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Crossref
Publication Date
Mon Jun 15 2020
Journal Name
Al-academy
Kinetic diversity of the camera in the structure of the cinematographic scene: وفاء سعدي صالح
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  Highlighting the role of the movement and its dramatic dimensions, as an artistic product, whether at the level of cinema or television in general, and the stages of its influence within the structure of the cinematographic scene in particular, had an effective role in the continuation of the structure of the event according to its dramatic and aesthetic process, and from this the research problem crystallized in the following question: What is How the kinetic diversity of the camera in the structure of the cinematographic scene is achieved to achieve the maximum possible benefit by extrapolating all opinions in line with the objectives of the research, the research presented and two topics and the introduction were divided, which

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Crossref
Publication Date
Fri Jun 01 2018
Journal Name
Journal Of The College Of Languages (jcl)
Le thème de la solitude et la structure narrative dans Le Procès-verbal de Jean Marie Gustave Le Clézio The Theme of Solitude and Narrative Structure in the Novel of “Trail ” of Jean Marie Gustave Le Clézio
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Abstract

     This paper tackles the theme of alienation as being a concurrent state of human being from birth to death; so extensive is the description of this state by writers. Alienation has been a product of their hard experiences and miserable lives. One such writer is Jean-Marie Gustave le Clézio who was so perfect in describing alienation in his works. Upon so many occasions, he imagined one or more of his characters as living in a chaotic world and so lived safely in alienation. The novel "Le Procès-Verbal" is one of the most important of his works. This paper deals with e the narrative structure of novel while shedding light on the hero's alienation: its essence and causes.

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Publication Date
Sun Jan 12 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Periodontal health status of heavy and light smokers and its correlation with salivary superoxide dismutase enzyme (A comparative study)
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Background: Periodontal disease is a chronic bacterial infection that affects the gingiva and bone supporting the teeth. Smoking, which is an important risk factor for periodontitis, induce oxidative stress in the body and cause an imbalance between reactive oxygen species (ROS) and antioxidants, such as superoxide dismutase (SOD). This study aimed to evaluate the influence of smoking on periodontal health status by estimating the levels of salivary SOD level in non-smokers (controls) and light and heavy smokers and to test the correlation between the SOD enzyme level and the clinical periodontal parameters in each group. Materials and Methods: The study sample consisted of 75 male, with age ranged from 35 to 50 years. Clinically, the perio

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Publication Date
Mon Oct 01 2012
Journal Name
Iraqi Journal Of Physics
Ab–Initio large unit cell calculations of the electronic structure of Si and Ge nanocrystals
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Ab – initio restricted Hartree - Fock method within the framework of large unit cell (LUC) formalism is used to investigate the electronic structure of Si and Ge nanocrystals. The surface and core properties are investigated. A large unit cell of 8 atoms is used in the present analysis. Cohesive energy, energy gap, conduction and valence band widths are obtained from the electronic structure calculations. The results are compared with available experimental data and theoretical results of other investigators. The calculated lattice constant is found to be slightly larger than the corresponding experimental value because we use only 8 atoms and we compared the results with that of the bulk crystals, nanoclusters are expected to have str

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Publication Date
Wed May 10 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Gross and Histological Structure of the Caudal Fin of Adult Mosquitofish , Gambusia Affinis , (Baird & Girard)
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The  present  study  showed  that  the  caudal  fin  of  adult mosquitofish  (Gambusia  affinis)  is  homocercal  and  rounded . It  consists  of  22-24 fin rays (Lepidotrichia) . Each fin ray  consists  of  many  segments . Some of these rays are short and  unbranched  whereas  others long and branched dichotomously. Pigment cells are shown to be dispersed on the fin and they are condensened at the edges of the fin rays and at the regions of their dichotomy .        Histologically the transverse section of the fin is surrounded by a fin membrane (composed of epidermis and dermis)

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Publication Date
Mon May 01 2023
Journal Name
Environmental Nanotechnology, Monitoring & Management
Photodegradation of tetracycline antibiotic by ternary recyclable Z-scheme g-C3N4/Fe3O4/Bi2WO6/Bi2S3 photocatalyst with improved charge separation efficiency: Characterization and mechanism studies
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Scopus Crossref
Publication Date
Tue Jan 30 2024
Journal Name
International Journal Of Engineering Pedagogy (ijep)
The Impact of Two Proposed Strategies Based on Active Learning on Students' Achievement at the Computer and Their Social Intelligence
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Active learning is a teaching method that involves students actively participating in activities, exercises, and projects within a rich and diverse educational environment. The teacher plays a role in encouraging students to take responsibility for their own education under their scientific and pedagogical supervision and motivates them to achieve ambitious educational goals that focus on developing an integrated personality for today’s students and tomorrow’s leaders. It is important to understand the impact of two proposed strategies based on active learning on the academic performance of first-class intermediate students in computer subjects and their social intelligence. The research sample was intentionally selected, consis

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Scopus (2)
Scopus Clarivate Crossref
Publication Date
Sat Jan 27 2024
Journal Name
History Of Medicine
Developing and Validating a Spectrophotometric Method for Estimating Antifungal (Nystatin) in its Pure Form Pharmaceutical Formulation Using Tetrachloro-1,4 benzoquinone
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The UV−VIS absorption spectroscopy technique was used to study the formation of a new complex of charge transfer (CT) between bioactive organic molecules as (Nystatin) containing both a π-electrons from a conjugated system and lone-pair of electrons (amine) with Tetrachloro-1,4 benzoquinone (TCBQ) as a π-acceptor in which the transferred electron goes into its vacant anti-bonding molecular orbitals. The Tyrian purple-colored complex formed was quantitatively measured at 544 nm. This complex shows obeying Beer's law within the concentration range of (10-90) μg.ml-1The stoichiometry of the formed complex between the (Nys.) and (TCBQ) was found 1:2 as evaluated by continuous variation (Job's method) and mole ratio method The value of mola

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