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2022 ◽  
Author(s):  
Govind Sidhardh ◽  
Adithi Ajith ◽  
Ebin Sebastian ◽  
Mahesh Hariharan ◽  
Anil Shaji

Excitonic energy transfer in light harvesting complexes, the primary process of photosynthesis, operates with near-unity efficiency. Experimental and theoretical studies suggest that quantum mechanical wave-like motion of excitons in the pigment-protein complex may be responsible for this quantum efficiency. Observed coherent exciton dynamics can be modelled completely only if we consider the interaction of the exciton with its complex environment. While it is known that the relative orientation of the chromophore units and reorganisation energy are important design elements, the role of a structured phonon environment is often not considered. The purpose of this study is to investigate the role of a structured immediate phonon environment in determining the exciton dynamics and the possibility of using it as an optimal design element. Through the case study of dithia-anthracenophane, a bichromophore using the Hierarchical Equations Of Motion formalism, we show that the experimentally observed coherent exciton dynamics can be reproduced only by considering the actual structure of the phonon environment. While the slow dephasing of quantum coherence in dithia-anthracenophane can be attributed to strong vibronic coupling to high-frequency modes, vibronic quenching is the source of long oscillation periods in population transfer. This study sheds light on the crucial role of the structure of the immediate phonon environment in determining the exciton dynamics. We conclude by proposing some design principles for sustaining long-lived coherence in molecular systems.


2021 ◽  
Vol 8 (4) ◽  
pp. 298-300
Author(s):  
Satish M Patel ◽  
Bhadreshkumar P Vaghela

The status of anatomical education in modern medical programs is a cornerstone of medicine. Anatomy is one of the basic subjects in First Year MBBS curriculum. Apart from important it is also a lengthy subject to complete in allocated time duration of First MBBS. There are various subdivisions of anatomy like gross anatomy, developmental anatomy, microscopic anatomy, genetics, surface anatomy, radiological anatomy etc. Out of which gross anatomy is difficult to understand as time constraint is there in duration of First MBBS. In medical and allied branches total hours allocated for anatomy teaching and laboratory practical hours have reduced. Result in triggered the emergence of innovative ideas to maximize students learning. While studying the gross anatomy three-dimensional orientation is must to learn actual structure and relation with other viscera and vessels. Traditional way of teaching anatomy uses wall charts, books, slides, anatomical specimens, and practical anatomy as teaching resources and methods. It is fact that in most institutes, three dimensional models are available in their Anatomy Museum, but many Anatomists have complained about fault in exact structure, labelling and it’s relationship in these models because sometime these models are made by amateur technicians. As the medical education expanded and the reduction in human anatomical specimens due to shortage of dead body donations, as well as the limitations of time, place and other resources for anatomical training, the quality of anatomy teaching has been seriously affected. Apart from shortage of these resources, another big issue with development of skill laboratory which is now mandatory as per new NMC guidelines. Establishment of skill lab requires ample amount of finance. Though, skill lab can provide excellent resources to meet the existing lacunae in teaching Anatomy to students by virtual media and simulations. Latest innovations in better teaching aids in Anatomy, in market virtual dissection table is available now, which can provide in depth understanding and orientation of three-dimensional body structures. But as mentioned above, the cost of this virtual dissection table is too high that every institute can not able to afford it. In this situation, to provide better understanding and three-dimensional orientation to students making hand made models from cheap and easily available materials are better options for teachers and students as they can make themselves.Anatomy is a discipline where spatial visualization is of importance. Even anatomy textbooks and atlases provide two-dimensional static anatomical illustrations. To teach some anatomical structures by traditional cadaveric dissection or by traditional lectures is difficult. Some of the structures like gross anatomy of urinary bladder or facial nerve anatomy are difficult to learn by textbook which cannot give exact perception of real anatomy. Additionally, many structure get distorted while removing from cadaver or not able to trace even. In some cases, specific models are also not available for instance course of facial nerve from origin to its termination where hand-made models give excellent three-dimensional understanding. For students’ proper anatomical knowledge of anatomy/organs help them to improve surgical skills. Finally, surgical outcome will be better with less morbidity and mortality.


Author(s):  
Irina Cojocaru ◽  
Gheorghe Cuciureanu ◽  
Igor Cojocaru

"Lately, an increasing number of countries have set up national bibliographic databases, which aim to achieve more comprehensive coverage of the national research outputs. These databases both increase the visibility of national publications and compensate the limited coverage of traditional citation databases, such as Scopus or Web of Science. National bibliographic databases are being increasingly used by a wide variety of stakeholders for numerous purposes, ranging from basic information retrieval and research outputs overview to bibliometric analysis, evaluation and research funding. The Republic of Moldova set up its national bibliographic database – National Bibliometric Instrument (IBN) in 2011. Nowadays, IBN includes over 113.000 articles published in national scientific journals, as well as conference proceedings from the Republic of Moldova starting from 1993 to date, with over 90% of publications indexed by Google Academic. IBN is used for the evaluation of national scientific journals and provides valuable insights on the overall evolution and trends of national research outputs, but is not being used for research funding. This paper aims to describe the history, actual structure and user possibilities of IBN. It also aims to analyse IBN design, organisation, maintenance and usage from the perspective of the Manual of good practices regarding national bibliographic databases, developed in the context of the ‘European Network for Research Evaluation in the Social Sciences and Humanities’ ENRESSH. Finally, the paper intends to provide a set of recommendations for IBN reengineering and improvement"


Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3963
Author(s):  
Florin Bucatariu ◽  
Carmen Teodosiu ◽  
Irina Morosanu ◽  
Daniela Fighir ◽  
Ramona Ciobanu ◽  
...  

Advanced wastewater treatment processes are required to implement wastewater reuse in agriculture or industry, the efficient removal of targeted priority and emerging organic & inorganic pollutants being compulsory (due to their eco-toxicological and human health effects, bio-accumulative, and degradation characteristics). Various processes such as membrane separations, adsorption, advanced oxidation, filtration, disinfection may be used in combination with one or more conventional treatment stages, but technical and environmental criteria are important to assess their application. Natural and synthetic polyelectrolytes combined with some inorganic materials or other organic or inorganic polymers create new materials (composites) that are currently used in sorption of toxic pollutants. The recent developments on the synthesis and characterization of composites based on polyelectrolytes, divided according to their macroscopic shape— beads, core-shell, gels, nanofibers, membranes—are discussed, and a correlation of their actual structure and properties with the adsorption mechanisms and removal efficiencies of various pollutants in aqueous media (priority and emerging pollutants or other model pollutants) are presented.


2021 ◽  
Vol 11 (22) ◽  
pp. 10591
Author(s):  
Lijun Qiao ◽  
Luo Xiao ◽  
Qingsheng Luo ◽  
Minghao Li ◽  
Jianfeng Jiang

In this paper, an optimized kinematic modeling method to accurately describe the actual structure of a mobile manipulator robot with a manipulator similar to the universal robot (UR5) is developed, and an improved self-collision detection technology realized for improving the description accuracy of each component and reducing the time required for approximating the whole robot is introduced. As the primary foundation for trajectory tracking and automatic navigation, the kinematic modeling technology of the mobile manipulator has been the subject of much interest and research for many years. However, the kinematic model established by various methods is different from the actual physical model due to the fact that researchers have mainly focused on the relationship between driving joints and the end positions while ignoring the physical structure. To improve the accuracy of the kinematic model, we present a kinematic modeling method with the addition of key points and coordinate systems to some components that failed to model the physical structure based on the classical method. Moreover, self-collision detection is also a primary problem for successfully completing the specified task of the mobile manipulator. In traditional self-collision detection technology, the description of each approximation is determined by the spatial transformation of each corresponding component in the mobile manipulator robot. Unlike the traditional technology, each approximation in the paper is directly established by the physical structure used in the kinematic modeling method, which significantly reduces the complicated analysis and shortens the required time. The numerical simulations prove that the kinematic model with the addition of key point technology is similar to the actual structure of mobile manipulator robots, and the self-collision detection technology proposed in the article effectively improves the performance of self-collision detection. Additionally, the experimental results prove that the kinematic modeling method and self-collision detection technology outlined in this paper can optimize the inverse kinematics solution.


2021 ◽  
Vol 2069 (1) ◽  
pp. 012068
Author(s):  
Markus Pau ◽  
Targo Kalamees ◽  
Urve Kallavus

Abstract Improving of exterior walls in historic and traditional buildings is often only possible with interior thermal insulation. The actual structure and material properties of the existing exterior wall are usually the main unknown factors. Therefore, field measurements with small mock-ups are helpful before large-scale renovation. The current study analyses by field measurements the hygrothermal performance of internally insulated massive stone wall. Two different hemp concrete mixes were developed for the insulation. Temperature and humidity conditions were measured periodically over one year period. Results showed a very low drying rate of hemp concrete interior insulation. The external side of hemp concrete insulation will stay moist for a very long period. Temperature of coarse hemp concrete was slightly higher during the cold period. Wooden studs used to install hemp concrete will stay in moist areas for a long period. Temperature drop below 0 °C shows that interior insulation should be durable for freezing-thawing cycles. Drying out of constructional moisture is absolutely necessary for hygrothermal design. Before considering large-scale renovations, it is necessary to further assess the long term durability and performance of hemp concrete in a moist environment. The temperature increase on the interior surface could slightly improve indoor thermal comfort.


Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6100
Author(s):  
Dongli Wang ◽  
Jun Xiao ◽  
Xiangwen Ju ◽  
Mingyue Dou ◽  
Liang Li ◽  
...  

The purpose of this paper is to study the effects of different trajectory planning methods on the mechanical properties of components. The scope of the research includes finite element simulation calculation and experimental tests of the actual structure. The test shall be carried out in the whole load range until the failure of the structure occurs. Taking the composite conical shell as an example, a variable angle initial path generation method of the conical shell surface is proposed, and the parallel offset algorithms based on partition and the circumferential averaging are proposed to fill the surface. Then, finite element analysis is carried out for the paths that satisfy the manufacturability requirements, the analysis results show that the maximum deformation and maximum transverse as well as longitudinal stress of fiber of circumferential averaging variable angle path conical shell are reduced by 16.3%, 5.85%, and 19.76%, respectively, of that of the partition variable angle path. Finally, the strength analysis of conical shells manufactured by different trajectory design schemes is carried out through finite element analysis and actual failure tests. The finite element analysis results are in good agreement with the experimental results of the actual structure. The results show that the circumferential uniform variable angle has good quality, and it is proved that the path planning algorithm that coordinates path planning and defect suppression plays an important role in optimizing placement trajectory and improving mechanical properties of parts.


2021 ◽  
Vol 15 ◽  
Author(s):  
Martina Schifferer ◽  
Nicolas Snaidero ◽  
Minou Djannatian ◽  
Martin Kerschensteiner ◽  
Thomas Misgeld

Ultrastructural analysis of discrete neurobiological structures by volume scanning electron microscopy (SEM) often constitutes a “needle-in-the-haystack” problem and therefore relies on sophisticated search strategies. The appropriate SEM approach for a given relocation task not only depends on the desired final image quality but also on the complexity and required accuracy of the screening process. Block-face SEM techniques like Focused Ion Beam or serial block-face SEM are “one-shot” imaging runs by nature and, thus, require precise relocation prior to acquisition. In contrast, “multi-shot” approaches conserve the sectioned tissue through the collection of serial sections onto solid support and allow reimaging. These tissue libraries generated by Array Tomography or Automated Tape Collecting Ultramicrotomy can be screened at low resolution to target high resolution SEM. This is particularly useful if a structure of interest is rare or has been predetermined by correlated light microscopy, which can assign molecular, dynamic and functional information to an ultrastructure. As such approaches require bridging mm to nm scales, they rely on tissue trimming at different stages of sample processing. Relocation is facilitated by endogenous or exogenous landmarks that are visible by several imaging modalities, combined with appropriate registration strategies that allow overlaying images of various sources. Here, we discuss the opportunities of using multi-shot serial sectioning SEM approaches, as well as suitable trimming and registration techniques, to slim down the high-resolution imaging volume to the actual structure of interest and hence facilitate ambitious targeted volume SEM projects.


2021 ◽  
Vol 42 (1) ◽  
Author(s):  
Hans-Georg Wuench

The OT books, Ezra and Nehemiah, are to be considered as one book. This is more or less the common conviction of most OT scholars today. However, their redaction process raises many questions. What is their relation to the book of Chronicles, and how is their actual structure to be understood? Why do we find two almost identical lists of returnees from exile in Ezra 2 and Nehemiah 7? What about the differences between these lists? This article understands the structure of Ezra-Nehemiah as a consciously created literary unit, where the two lists of returnees serve as an important part of the literary structure. The author works on the assumption of the so-called new literary criticism, understanding the narrative in the book on a synchronic basis. He shows that the book of Ezra-Nehemiah can indeed be understood as one literary unit, and that the two lists of returnees function as a literary means to structure the book. There is therefore no need to ‘re-organise’ the narrated events in Ezra-Nehemiah according to an alleged different chronological order.Intradisciplinary and/or interdisciplinary implications: The study argued for a canonical and synchronic approach to biblical narratives. The biblical texts should be understood as consciously created narratives, where the apparent discrepancies are important aspects of the narrative fixture.


Author(s):  
Bhavesh Patel ◽  
Alessio Gizzi ◽  
Javad Hashemi ◽  
Yousif Awakeem ◽  
Hans Gregersen ◽  
...  

The gastrointestinal (GI) tract is a continuous channel through the body that consists of the esophagus, the stomach, the small intestine, the large intestine, and the rectum. Its primary functions are to move the intake of food for digestion before storing and ultimately expulsion of feces from the rectum through the anal sphincter. The mechanical behavior of GI tissues thus plays a crucial role for GI function in health and disease. The mechanical properties are typically characterized by a constitutive biomechanical model, which is a mathematical representation of the relation between load and deformation in a tissue. Hence, validated biomechanical constitutive models are essential to characterize and simulate the mechanical behavior of the GI tract under physiological and pathological conditions. Numerous constitutive models have consequently been proposed over the past three decades, mainly inspired by work done in cardiovascular tissues. Here, a comprehensive review of these constitutive models is provided. This review is limited to studies where a model of the strain energy function is proposed to characterize the stress-strain relation of a GI tissue. Several needs are identified for more advanced modeling of GI biomechanics including: 1) Microstructural models that provide actual structure-function relations; 2) Validation of coupled electro-mechanical models accounting for active muscle contractions; 3) Human data under physiological and pathological conditions to develop and validate models. The findings from this review provide guidelines for using existing constitutive models as well as perspective and directions for future studies aimed at establishing new constitutive models for GI tissues.


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