•The rich chemistry of UTL solid-state transformations is depicted.•Five approaches are described for a topological transformation from UTL to IPC-2.•IPC-2 is found to be highly preferred and stable ...structure.
The unique features of the germanosilicate zeolite possessing the UTL framework topology offer various post-synthetic modifications such as ‘top-down’, ‘inverse sigma’ or solid-state transformations. The presented work describes several different synthetic routes generating the IPC-2 type zeolite (OKO topology) utilizing UTL as the parent material. In total, five approaches were investigated which exhibit this topological transformation from germanosilicate UTL to OKO type material: (1) alkoxysilylation of the layered precursor (IPC-1P) formed by hydrolysis of UTL; (2) direct conversion of UTL by treatment in 7–12M hydrochloric acid; (3) direct transformation under mild conditions of water and ammonium nitrate solution on Al- and B-UTL; (4) repeated calcinations of boron-containing UTL; (5) using organic solutions as self-stabilization agents. Resulting materials were examined by powder XRD, nitrogen sorption, SEM and EDX. Briefly, all the materials possessed the same OKO topology but had differing BET surface areas and micropore volumes in the ranges of 201–493m2/g and 0.095–0.189cm3/g, respectively. The morphologies of crystals were very similar, while the size of them varied between 10 and 50μm. The main goal of the study was to emphasize the complexity of post-synthetic UTL zeolite chemistry and the diverse range of solid-state transformations possible.
The mechanisms by which the vertebrate brain develops its characteristic three-dimensional structure are poorly understood. The brain ventricles are a highly conserved system of cavities that form ...very early during brain morphogenesis and that are required for normal brain function. We have initiated a study of zebrafish brain ventricle development and show here that the neural tube expands into primary forebrain, midbrain and hindbrain ventricles rapidly, over a 4-hour window during mid-somitogenesis. Circulation is not required for initial ventricle formation, only for later expansion. Cell division rates in the neural tube surrounding the ventricles are higher than between ventricles and, consistently, cell division is required for normal ventricle development. Two zebrafish mutants that do not develop brain ventricles are snakehead and nagie oko . We show that snakehead is allelic to small heart , which has a mutation in the Na + K + ATPase gene atp1a1a.1 . The snakehead neural tube undergoes normal ventricle morphogenesis; however, the ventricles do not inflate, probably owing to impaired ion transport. By contrast, mutants in nagie oko , which was previously shown to encode a MAGUK family protein, fail to undergo ventricle morphogenesis. This correlates with an abnormal brain neuroepithelium, with no clear midline and disrupted junctional protein expression. This study defines three steps that are required for brain ventricle development and that occur independently of circulation: (1) morphogenesis of the neural tube, requiring nok function; (2) lumen inflation requiring atp1a1a.1 function; and (3) localized cell proliferation. We suggest that mechanisms of brain ventricle development are conserved throughout the vertebrates.
Building on the successful formula of the first edition, Martin Tovée offers a concise but detailed account of how the visual system is organised and functions to produce visual perception. He takes ...his readers from first principles; the structure and function of the eye and what happens when light enters, to how we see and process images, recognise patterns and faces, and through to the most recent discoveries in molecular genetics and brain imaging, and how they have uncovered a host of new advances in our understanding of how visual information is processed within the brain. Incorporating new material throughout, including almost 50 new images, every chapter has been updated to include the latest research, and culminates in helpful key points, which summarise the lessons learnt. This book is an invaluable course text for students within the fields of psychology, neuroscience, biology and physiology.
The article presents changes in the course of ice phenomena on Lake Morskie Oko over 50 years. It comprises detailed data of the course of the main parameters of ice regime of the lake in the years ...1963–1970. Such a reference period yielded substantial differences in the obtained values of trends in comparison with the period 1971–2010, which is most common in literature. The trends obtained differed substantially from those describing the years 1971–2010, and the change in the parameters – scaled to a year of the analysed period – was about half the size. Attention was also drawn to the practical aspect of the changes in the duration and thickness of ice cover on the lake. In the years 1963–2012 the period of safe movement on the frozen lake was reduced by only 10 days.
Many vertebrate organs are derived from monolayered epithelia that undergo morphogenesis to acquire their shape. Whereas asymmetric left/right gene expression within the zebrafish heart field has ...been well documented, little is known about the tissue movements and cellular changes underlying early cardiac morphogenesis. Here, we demonstrate that asymmetric involution of the myocardium of the right-posterior heart field generates the ventral floor, whereas the noninvoluting left heart field gives rise to the dorsal roof of the primary heart tube. During heart tube formation, asymmetric left/right gene expression within the myocardium correlates with asymmetric tissue morphogenesis. Disruption of left/right gene expression causes randomized myocardial tissue involution. Time-lapse analysis combined with genetic analyses reveals that motility of the myocardial epithelium is a tissue migration process. Our results demonstrate that asymmetric morphogenetic movements of the 2 bilateral myocardial cell populations generate different dorsoventral regions of the zebrafish heart tube. Failure to generate a heart tube does not affect the acquisition of atrial versus ventricular cardiac cell shapes. Therefore, establishment of basic cardiac cell shapes precedes cardiac function. Together, these results provide the framework for the integration of single cell behaviors during the formation of the vertebrate primary heart tube.
Zbuntowane oko Giżycki, Marcin
Kwartalnik filmowy,
01/2020
111
Journal Article
Recenzirano
Odprti dostop
The eye fascinates artists, writers, and filmmakers for ages. Usually it appears in the violent context, is plucked out, blinded, etc. The author is deliberating on this phenomenon, but he is ...focusing on two films which are not a celebration of cruelty: "Film" by Samuel Beckett and Alan Schneider (1965) and "The Cage" by Sidney Peterson (1947). Both films are of similar length – twenty-something minutes – and are mute. But they have also this in common that they can be interpreted as stories about split personalities.
The primary purpose of this study was to examine the status and utilization of information and communication technologies in polytechnics in South Eastern States of Nigeria. The population of the ...study consisted of 120 Secretarial Studies teachers. Questionnaire was used as instrument for gathering data for the study. Data collected were analyzed using mean scores, percentage and frequency tables. The null hypothesis established for the study was tested using t-test for paired samples as reported from computer-generated analysis. Results of the study showed that: (a) most Information and communication technologies were not available meaning that rate of utilization of ICT is low. It was found that ICT posed very serious challenges to Secretarial Studies Teachers in the polytechnics. Given the present low utilization rate of ICT in Polytechnics, the administration of Polytechnic should encourage private sector funding of polytechnic education by appealing to industries that are the direct beneficiaries of polytechnic education to make donation to the polytechnics. (f) The Association of Business Education of Nigeria (ABEN) as its contribution to professional development should organize regular mandatory training programmes for members as is practice by other professional bodies.
Táto štúdia pojednáva o možnostiach využitia vizuálnych systémoch v dopravných technológiách. Rozoberá možnosti vizuálneho systému ako systému pre zvýšenie vonkajšej bezpečnosti tak aj systému pre ...počítačové pozorovanie a pre monitorovanie ostražitosti vodiča za volantom. Dôvod na skonštruovanie takéhoto systému bol hlavne predísť častým dopravným nehodám, ktorých príčina je veľmi často mikrospánok vodiča. Práve zmenšený stupeň ostražitosti vodiča sa stal problémom vážneho záujmu pre spoločnosť.
In the past few years, there has been an explosion of eye movement research in cognitive science and neuroscience. This has been due to the availability of ‘off the shelf’ eye trackers, along with ...software to allow the easy acquisition and analysis of eye movement data. Accompanying this has been a realisation that eye movement data can be informative about many different aspects of perceptual and cognitive processing. Eye movements have been used to examine the visual and cognitive processes underpinning a much broader range of human activities, including, language production, dialogue, human computer interaction, driving behaviour, sporting performance, and emotional states. Finally, in the past thirty years, there have been real advances in our understanding of the neural processes that underpin eye movement behaviour. The Oxford Handbook of Eye Movements provides a comprehensive review of the entire field of eye movement research. In over fifty articles, it reviews the developments that have so far taken place, the areas actively being researched, and looks at how the field is likely to develop in the coming years. The first section considers historical and background material, before moving onto a second section on the neural basis of eye movements. The third and fourth sections look at visual cognition and eye movements and eye movement pathology and development. The final sections consider eye movements and reading and language processing and eye movements.
TOUGHENING ENVIRONMENTAL LEGISLATION, NATIONAL AND SUPRA-national environmental product policies and growing customer demands are focusing the attention of companies on the environmental and broader ...social issues linked to the creation and delivery of their products and services. There is now an urgent need for appropriate management structures, practical tools and increased awareness among all stakeholders in the product development process and throughout the entire product life-cycle.
PDF
