scholarly journals Structural Diversity of Photoswitchable Sphingolipids for Optodynamic Control of Lipid Raft Microdomains

2021 ◽  
Author(s):  
Nina Hartrampf ◽  
Samuel M. Leitao ◽  
Nils Winter ◽  
Henry Toombs-Ruane ◽  
James A. Frank ◽  
...  
Keyword(s):  
Lipid Raft ◽  
High Speed ◽  
Structural Diversity ◽  
Line Tension ◽  
Vital Role ◽  
Supported Bilayers ◽  
Liquid Ordered ◽  
Raft Domains ◽  
Lateral Localization

AbstractSphingolipids are a structurally diverse class of lipids predominantly found in the plasma membrane of eukaryotic cells. These lipids can laterally segregate with other saturated lipids and cholesterol into lipid rafts; liquid-ordered (Lo) microdomains that act as organizing centers within biomembranes. Owing the vital role of sphingolipids for lipid segregation, controlling their lateral localization is of utmost significance. Hence, we made use of the light-induced trans-cis isomerization of azobenzene-modified acyl chains, to develop a set of photoswitchable sphingolipids, with different headgroups (hydroxyl, galactosyl, phosphocholine) and backbones (sphingosine, phytosphingosine, tetrahydropyran (THP)-blocked sphingosine), able to shuttle between liquid-ordered (Lo) and liquid-disordered (Ld) regions of model membranes upon irradiation with UV-A (λ = 365 nm) and blue (λ = 470 nm) light, respectively. Using combined high-speed atomic force microscopy, fluorescence microscopy, and force spectroscopy, we investigated how these active sphingolipids laterally remodel supported bilayers upon photo-isomerization, notably in terms of domain area changes, height mismatch, line tension, and membrane piercing. Hereby, we show that all sphingosine-(Azo-β-Gal-Cer, Azo-SM, Azo-Cer) and phytosphingosine-based (Azo-α-Gal-PhCer, Azo-PhCer) photolipids behave similarly, promoting a reduction in Lo domain area when in the UV-adapted cis-isoform. In contrast, azo-sphingolipids having THP groups that block H-bonding at the sphingosine backbone (Azo-THP-SM, Azo-THP-Cer) induce an increase in the Lo domain area when in cis, accompanied by a major rise in height mismatch and line tension. These changes were fully reversible upon blue light-triggered isomerization of the various lipids back to trans, pinpointing the role of interfacial interactions for the formation of stable Lo lipid raft domains.

scholarly journals Signaling and cytoskeletal requirements in erythroblast enucleation

Blood ◽  
2012 ◽  
Vol 119 (25) ◽  
pp. 6118-6127 ◽  
Author(s):  
Diamantis G. Konstantinidis ◽  
Suvarnamala Pushkaran ◽  
James F. Johnson ◽  
Jose A. Cancelas ◽  
Stefanos Manganaris ◽  
...  
Keyword(s):  
Lipid Raft ◽  
High Speed ◽  
Rac Gtpases ◽  
Speed Flow ◽  
Multistep Process ◽  
Preparatory Stage ◽  
Genetic Deletion ◽  
Membrane Signaling ◽  
Analysis Protocol

Abstract To understand the role of cytoskeleton and membrane signaling molecules in erythroblast enucleation, we developed a novel analysis protocol of multiparameter high-speed cell imaging in flow. This protocol enabled us to observe F-actin and phosphorylated myosin regulatory light chain (pMRLC) assembled into a contractile actomyosin ring (CAR) between nascent reticulocyte and nucleus, in a population of enucleating erythroblasts. CAR formation and subsequent enucleation were not affected in murine erythroblasts with genetic deletion of Rac1 and Rac2 GTPases because of compensation by Rac3. Pharmacologic inhibition or genetic deletion of all Rac GTPases altered the distribution of F-actin and pMRLC and inhibited enucleation. Erythroblasts treated with NSC23766, cytochalasin-D, colchicine, ML7, or filipin that inhibited Rac activity, actin or tubulin polymerization, MRLC phosphorylation, or lipid raft assembly, respectively, exhibited decreased enucleation efficiency, as quantified by flow cytometry. As assessed by high-speed flow-imaging analysis, colchicine inhibited erythroblast polarization, implicating microtubules during the preparatory stage of enucleation, whereas NSC23766 led to absence of lipid raft assembly in the reticulocyte-pyrenocyte border. In conclusion, enucleation is a multistep process that resembles cytokinesis, requiring establishment of cell polarity through microtubule function, followed by formation of a contractile actomyosin ring, and coalescence of lipid rafts between reticulocyte and pyrenocyte.

Asiana Airlines Flight 214

2014 ◽  
Vol 4 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Stephanie Chow ◽  
Stephen Yortsos ◽  
Najmedin Meshkati
Keyword(s):  
Human Factors ◽  
Aviation Safety ◽  
Cultural Factors ◽  
Vital Role ◽  
Cultural Issues ◽  
Flight Crew ◽  
Pilot Performance ◽  
Engineering Designs ◽  
Flight Deck

This article focuses on a major human factors–related issue that includes the undeniable role of cultural factors and cockpit automation and their serious impact on flight crew performance, communication, and aviation safety. The report concentrates on the flight crew performance of the Boeing 777–Asiana Airlines Flight 214 accident, by exploring issues concerning mode confusion and autothrottle systems. It also further reviews the vital role of cultural factors in aviation safety and provides a brief overview of past, related accidents. Automation progressions have been created in an attempt to design an error-free flight deck. However, to do that, the pilot must still thoroughly understand every component of the flight deck – most importantly, the automation. Otherwise, if pilots are not completely competent in terms of their automation, the slightest errors can lead to fatal accidents. As seen in the case of Asiana Flight 214, even though engineering designs and pilot training have greatly evolved over the years, there are many cultural, design, and communication factors that affect pilot performance. It is concluded that aviation systems designers, in cooperation with pilots and regulatory bodies, should lead the strategic effort of systematically addressing the serious issues of cockpit automation, human factors, and cultural issues, including their interactions, which will certainly lead to better solutions for safer flights.

Energy Efficiency Analysis in ERA using NFL-BA Algorithm

2020 ◽  
pp. 340-348
Author(s):  
Palky Mehta ◽  
H. L. Sharma
Keyword(s):  
Cluster Head ◽  
Vital Role ◽  
Wireless Sensor ◽  
Energy Usage ◽  
Cluster Heads ◽  
Comparison Results ◽  
Current Scenario ◽  
Energy Efficiency Analysis ◽  
Selection Of

In the current scenario of Wireless Sensor Network (WSN), power consumption is the major issue associated with nodes in WSN. LEACH technique plays a vital role of clustering in WSN and reduces the energy usage effectively. But LEACH has its own limitation in order to search cluster head nodes which are randomly distributed over the network. In this paper, ERA-NFL- BA algorithm is being proposed for selects the cluster heads in WSN. This algorithm help in selection of cluster heads can freely transform from global search to local search. At the end, a comparison has been done with earlier researcher using protocol ERA-NFL, which clearly shown that proposed Algorithm is best suited and from comparison results that ERA-NFL-BA has given better performance.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

Tertiary English-majored Students’ Perceptions toward the Role of Pronunciation in English Language Learning and their Practicing Strategies

2020 ◽  
Vol 6 (2) ◽  
pp. 264-279
Keyword(s):  
Language Learning ◽  
English Language ◽  
Vital Role ◽  
English Language Learning ◽  
Structured Interviews ◽  
Efl Learners ◽  
The University

Accurate pronunciation has a vital role in English language learning as it can help learners to avoid misunderstanding in communication. However, EFL learners in many contexts, especially at the University of Phan Thiet, still encounter many difficulties in pronouncing English correctly. Therefore, this study endeavors to explore English-majored students’ perceptions towards the role of pronunciation in English language learning and examine their pronunciation practicing strategies (PPS). It involved 155 English-majored students at the University of Phan Thiet who answered closed-ended questionnaires and 18 English-majored students who participated in semi-structured interviews. The findings revealed that students strongly believed in the important role of pronunciation in English language learning; however, they sometimes employed PPS for their pronunciation improvement. Furthermore, the results showed that participants tended to use naturalistic practicing strategies and formal practicing strategies with sounds, but they overlooked strategies such as asking for help and cooperating with peers. Such findings could contribute further to the understanding of how students perceive the role of pronunciation and their PPS use in the research’s context and other similar ones. Received 10th June 2019; Revised 12th March 2020; Accepted 12th April 2020

The role of Record of Rights (Khatian) in determining title or possession: An overview

IIUC Studies ◽  
2020 ◽  
Vol 15 ◽  
pp. 33-46
Author(s):  
Kalim Ullah
Keyword(s):  
Human Life ◽  
Vital Role ◽  
Critical Element ◽  
Human Beings ◽  
Supportive Evidence ◽  
Land Administration ◽  
Holy Quran ◽  
The Holy Quran ◽  
Religious Systems

Human beings are deeply related to land. Human beings take birth on land, live on land, die on land and mixes with land ultimately. As stated in the holy Quran: ‘We (Allah) created you (human beings) from the soil, we shall make you return to the soil and We shall call you back again from the soil’ (20:55). Human life is surrounded by soil i.e. land. So, land is a highly completed issue of human life involving economic, social, political, cultural and often religious systems. Land administration is thus a critical element and often a pre-condition for peaceful society and sustainable development. In administrating land, Khatian or record of rights plays a vital role to determine the rights and interests of the respective parties as supportive evidence. In this article, discussion is mainly made on the fact that Khatian or record of rights is not a document of title solely but it may be an evidence of title as well as possession. IIUC Studies Vol.15(0) December 2018: 33-46

A Court in Decline? Examining the Regality Court Records of Melrose, Roxburghshire, 1657–84

2020 ◽  
Vol 40 (1) ◽  
pp. 1-16
Author(s):  
Vivienne Dunstan
Keyword(s):  
Seventeenth Century ◽  
Local Community ◽  
Local Population ◽  
Local Area ◽  
Vital Role ◽  
Local Communities ◽  
Court Records ◽  
Seminal Work

McIntyre, in his seminal work on Scottish franchise courts, argues that these courts were in decline in this period, and of little relevance to their local population. 1 But was that really the case? This paper explores that question, using a particularly rich set of local court records. By analysing the functions and significance of one particular court it assesses the role of this one court within its local area, and considers whether it really was in decline at this time, or if it continued to perform a vital role in its local community. The period studied is the mid to late seventeenth century, a period of considerable upheaval in Scottish life, that has attracted considerable attention from scholars, though often less on the experiences of local communities and people.

Risk and Protective Factors in the Life of Youth in Relation to Resilience

2018 ◽  
Vol 52 (1) ◽  
pp. 50-59
Author(s):  
Silvia Barnová ◽  
Viola Tamášová
Keyword(s):  
Social Support ◽  
Protective Factors ◽  
School Psychologists ◽  
Social Environment ◽  
Social Services ◽  
Service Providers ◽  
Vital Role ◽  
Great Role ◽  
Health Service Providers

Abstract Introduction: A certain degree of stress is present in everyone’s life and young people are not an exception. Most of them show a certain degree of resilience and can cope with stressful situations without any difficulties, however there is a group of youth who live in toxic environments and need help. If there is a risk of failure due to the intensity of stressors; external formal and informal support have a great role to play as they have the potential to prevent negative developmental outcomes. Purpose: The authors’ intention was to make a review of available literature on the current issues of resilience research with a focus on the importance of protective factors in young people’s lives – especially when they are exposed to adversity. An emphasis is placed on the vital role of social support to individuals provided by schools as well as social services. Methods: In the presented literature review, multiple formal search methods including hand searching of key journals; electronic searching of journal databases and subject specific websites; reference scanning; and citation tracking were used. Conclusion: Individuals commonly demonstrate some level of resilience, yet most of them are able to deal with stressful situations without any harm. On the other hand, if the adversity is too high, the presence of social support provided by their social environment is important. In this context, good relationships in general and sufficient external protective factors provided by their social environment (schools, school psychologists, institutional social and health service providers) are important.

Knowledge creation in small building and construction firms

2013 ◽  
Vol 1 (1) ◽  
pp. 125-142 ◽  
Author(s):  
Susanne Durst ◽  
Ingi Runar Edvardsson ◽  
Guido Bruns
Keyword(s):  
Construction Industry ◽  
Knowledge Creation ◽  
Vital Role ◽  
Knowledge Sources ◽  
Structured Interviews ◽  
Construction Firms ◽  
External Knowledge ◽  
Body Of Knowledge ◽  
Small Building

Studies on knowledge creation are limited in general, and there is a particular shortage of research on the topic in small and medium-sized enterprises (SMEs). Given the importance of SMEs for the economy and the vital role of knowledge creation in innovation, this situation is unsatisfactory. Accordingly, the purpose of our study is to increase our understanding of how SMEs create new knowledge. Data are obtained through semi-structured interviews with ten managing directors of German SMEs operating in the building and construction industry. The findings demonstrate the influence of external knowledge sources on knowledge creation activities. Even though the managing directors take advantage of different external knowledge sources, they seem to put an emphasis on informed knowledge sources. The study´s findings advance the limited body of knowledge regarding knowledge creation in SMEs.

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