scholarly journals Metachronal waves in magnetic micro-robotic paddles for artificial cilia

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Matthew T. Bryan ◽  
Elizabeth L. Martin ◽  
Aleksandra Pac ◽  
Andrew D. Gilbert ◽  
Feodor Y. Ogrin
Keyword(s):  
Large Scale ◽  
Point Of Care ◽  
Hydrodynamic Response ◽  
Flow Speeds ◽  
Break Time ◽  
Large Scale Manufacture ◽  
Fresh Insight ◽  
Metachronal Waves ◽  
Insight Into ◽  
Phase Differences

AbstractBiological cilia generate fluid movement within viscosity-dominated environments using beating motions that break time-reversal symmetry. This creates a metachronal wave, which enhances flow efficiency. Artificially mimicking this behaviour could improve microfluidic point-of-care devices, since viscosity-dominated fluid dynamics impede fluid flow and mixing of reagents, limiting potential for multiplexing diagnostic tests. However, current biomimicry schemes require either variation in the hydrodynamic response across a cilia array or a complex magnetic anisotropy configuration to synchronise the actuation sequence with the driving field. Here, we show that simple modifications to the structural design introduce phase differences between individual actuators, leading to the spontaneous formation of metachronal waves. This generates flow speeds of up to 16 μm/s as far as 675 μm above the actuator plane. By introducing metachronal waves through lithographic structuring, large scale manufacture becomes feasible. Additionally, by demonstrating that metachronal waves emerge from non-uniformity in internal structural mechanics, we offer fresh insight into the mechanics of cilia coordination.

In Search of Machaut’s Poietics

2014 ◽  
Vol 31 (4) ◽  
pp. 395-430 ◽  
Author(s):  
Jordan Stokes
Keyword(s):  
Creative Process ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Rhetorical Reading ◽  
Fresh Insight ◽  
Insight Into

Guillaume de Machaut’s Le Remede de Fortune has often been described as a didactic work addressed to would-be poets. This essay argues that the Remede also should be read as an implicit work of rhetorical and musical instruction. To this end, the Remede is placed in dialogue with Machaut’s more explicit account of the creative process in the Prologue, with other romans à chansons, such as Nicole de Margival’s Dit de la panthère d'amours, and with medieval theories of rhetoric and music, eventually arriving at a rhetorical reading of the Remede's large-scale structure, a didactic reading of the work's musical interpolations, and a fresh insight into Machaut's understanding of his own creative process.

scholarly journals Integrating syphilis screening in a large-scale HIV prevention program for key populations: the Avahan experience from India

2013 ◽  
Vol 7 (06) ◽  
pp. 484-488 ◽  
Author(s):  
Mugundu Ramien Parthasarathy ◽  
Prakash Narayanan ◽  
Anjana Das ◽  
Anup Gurung ◽  
Parimi Prabhakar ◽  
...  
Keyword(s):  
Hiv Prevention ◽  
Prevention Program ◽  
Large Scale ◽  
Point Of Care ◽  
Key Populations ◽  
Immunochromatographic Strip ◽  
Transmitted Infection ◽  
Sexually Transmitted ◽  
Syphilis Screening ◽  
Strip Test

Introduction: Documented experiences from India on the implementation of syphilis screening in large-scale HIV prevention programs for “key populations at higher risk’ (KPs) are limited. Avahan is a large-scale HIV prevention program providing services to more than 300,000 KPs in six high HIV prevalence states of India since 2004. Avahan clinics provide a sexually transmitted infection service package which includes bi-annual syphilis screening. The trends in the coverage of syphilis screening among Avahan clinic attendees were studied retrospectively. Methodology: Screening was performed using either the Rapid Plasma Reagin (RPR) test or point-of-care immunochromatographic strip test (ICST). Clinic records from 2005 to 2009 were collated in an individual tracking database and analyzed with STATA-10. Results: Initially the coverage of syphilis screening (2.6% in 2005) was constrained by the availability and operational complexity of the RPR test. After its introduction in 2007, the use of ICST for screening increased from 7.4% to 77.0% and the proportion of clinic attendees screened increased from 9.0% to 21.6% during 2007-2009. The RPR reactivity rates declined from 6.6% (2006) to 4.4% (2009). Conclusion: The data showed improved rates of screening of clinic attendees and declining trends in sero-reactivity over time. The introduction of point-of-care syphilis tests may have contributed to the improved coverage of syphilis screening. The ICST may be considered for initial syphilis screening at other resource-constrained primary care sites in India such as ante-natal clinics and other KP interventions.

Stanlake Samkange’s Insufferable Zimbabwe: Distanciating Trauma from the Novel to Philosophy

2021 ◽  
Vol 8 (2) ◽  
pp. 158-176
Author(s):  
Jeanne-Marie Jackson
Keyword(s):  
Trauma Theory ◽  
The Novel ◽  
African Context ◽  
Independence Era ◽  
The Relationship ◽  
Fresh Insight ◽  
Insight Into

This article theorizes the Zimbabwean writer Stanlake Samkange’s turn from the novel to philosophy as an effort to circumvent the representational pressure exerted by African cultural traumatization. In breaking with the novel form to coauthor a philosophical treatise called Hunhuism or Ubuntuism in the same year as Zimbabwe achieves independence (1980), Samkange advances a comportment-based, deontological alternative to the psychic or subjective model of personhood that anchors trauma theory. Revisiting the progression from his most achieved novel, The Mourned One, to Hunhuism or Ubuntuism thus offers fresh insight into the range of options available to independence-era writers for representing the relationship between African individuality and collectivity. At the same time, it suggests a complementary and overlooked relationship between novelistic and philosophical forms in an African context.

scholarly journals Geo-Spatial Analysis of Population Density and Annual Income to Identify Large-Scale Socio-Demographic Disparities

2021 ◽  
Vol 10 (7) ◽  
pp. 432
Author(s):  
Nicolai Moos ◽  
Carsten Juergens ◽  
Andreas P. Redecker
Keyword(s):  
Population Density ◽  
Large Scale ◽  
Methodological Approach ◽  
Spatial Relationship ◽  
Postal Code ◽  
Annual Income ◽  
Choropleth Maps ◽  
Clustering Approach ◽  
Relationship Of ◽  
Insight Into

This paper describes a methodological approach that is able to analyse socio-demographic and -economic data in large-scale spatial detail. Based on the two variables, population density and annual income, one investigates the spatial relationship of these variables to identify locations of imbalance or disparities assisted by bivariate choropleth maps. The aim is to gain a deeper insight into spatial components of socioeconomic nexuses, such as the relationships between the two variables, especially for high-resolution spatial units. The used methodology is able to assist political decision-making, target group advertising in the field of geo-marketing and for the site searches of new shop locations, as well as further socioeconomic research and urban planning. The developed methodology was tested in a national case study in Germany and is easily transferrable to other countries with comparable datasets. The analysis was carried out utilising data about population density and average annual income linked to spatially referenced polygons of postal codes. These were disaggregated initially via a readapted three-class dasymetric mapping approach and allocated to large-scale city block polygons. Univariate and bivariate choropleth maps generated from the resulting datasets were then used to identify and compare spatial economic disparities for a study area in North Rhine-Westphalia (NRW), Germany. Subsequently, based on these variables, a multivariate clustering approach was conducted for a demonstration area in Dortmund. In the result, it was obvious that the spatially disaggregated data allow more detailed insight into spatial patterns of socioeconomic attributes than the coarser data related to postal code polygons.

scholarly journals Molecular architecture of the endocytic TPLATE complex

2021 ◽  
Vol 7 (9) ◽  
pp. eabe7999
Author(s):  
Klaas Yperman ◽  
Jie Wang ◽  
Dominique Eeckhout ◽  
Joanna Winkler ◽  
Lam Dai Vu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Structural Approach ◽  
Eukaryotic Cells ◽  
Molecular Architecture ◽  
Membrane Proteome ◽  
Complex Assembly ◽  
Membrane Interaction ◽  
Structural Insight ◽  
Fresh Insight ◽  
Insight Into

Eukaryotic cells rely on endocytosis to regulate their plasma membrane proteome and lipidome. Most eukaryotic groups, except fungi and animals, have retained the evolutionary ancient TSET complex as an endocytic regulator. Unlike other coatomer complexes, structural insight into TSET is lacking. Here, we reveal the molecular architecture of plant TSET [TPLATE complex (TPC)] using an integrative structural approach. We identify crucial roles for specific TSET subunits in complex assembly and membrane interaction. Our data therefore generate fresh insight into the differences between the hexameric TSET in Dictyostelium and the octameric TPC in plants. Structural elucidation of this ancient adaptor complex represents the missing piece in the coatomer puzzle and vastly advances our functional as well as evolutionary insight into the process of endocytosis.

scholarly journals Address of the President Sir Henry Dale, C.B.E., at the Anniversary Meeting, 1 December 1941

1942 ◽  
Vol 179 (978) ◽  
pp. 233-260 ◽  
Keyword(s):  
Technical College ◽  
High Speed ◽  
Large Scale ◽  
Electrical Engineering ◽  
The United States ◽  
The Past ◽  
Pure Mathematics ◽  
Symbolic Structure ◽  
The Church ◽  
Insight Into

This is the first occasion on which I have had the great honour of addressing the Royal Society on this anniversary of its foundation. According to custom, I begin with brief mention of those whom death has taken from our Fellowship during the past year, and whose memories we honour. Alfred Young (1873-1940), distinguished for his contributions to pure mathematics, was half brother to another of our Fellows, Sydney Young, a chemist of eminence. Alfred Young had an insight into the symbolic structure and manipulation of algebra, which gave him a special place among his mathematical contemporaries. After a successful career at Cambridge he entered the Church, and passed his later years in the country rectory of Birdbrook, Essex. His devotion to mathematics continued, however, throughout his life, and he published a steady stream of work in the branch of algebra which he had invented, and named ‘quantitative substitutional analysis’. He lived to see his methods adopted by Weyl in his quantum mechanics and spectroscopy. He was elected to our Fellowship in 1934. With the death of Miles Walker (1868-1941) the Society loses a pioneer in large-scale electrical engineering. Walker was a man of wide interests. He was trained first for the law, and even followed its practice for a period. Later he studied electrical engineering under Sylvanus Thompson at the Finsbury Technical College and became his assistant for several years. Thereafter, encouraged by Thompson, he entered St John’s College, Cambridge, with a scholarship, and graduated with 1st Class Honours in both the Natural Sciences and the Engineering Tripos. Having entered the service of the British Westinghouse Company, he was sent by them to the United States of America to study electrical engineering with the parent company in Pittsburgh. On his return to England he became their leading designer of high-speed electrical generators

Position Selectivity in Scene- and Object-Responsive Occipitotemporal Regions

2007 ◽  
Vol 98 (4) ◽  
pp. 2089-2098 ◽  
Author(s):  
Sean P. MacEvoy ◽  
Russell A. Epstein
Keyword(s):  
Large Scale ◽  
Scene Perception ◽  
Receptive Fields ◽  
Neural Responses ◽  
Retinal Position ◽  
Vertical Meridian ◽  
Retinal Stimulation ◽  
Natural Vision ◽  
Visual Hemifields ◽  
Insight Into

Complex visual scenes preferentially activate several areas of the human brain, including the parahippocampal place area (PPA), the retrosplenial complex (RSC), and the transverse occipital sulcus (TOS). The sensitivity of neurons in these regions to the retinal position of stimuli is unknown, but could provide insight into their roles in scene perception and navigation. To address this issue, we used functional magnetic resonance imaging (fMRI) to measure neural responses evoked by sequences of scenes and objects confined to either the left or right visual hemifields. We also measured the level of adaptation produced when stimuli were either presented first in one hemifield and then repeated in the opposite hemifield or repeated in the same hemifield. Although overall responses in the PPA, RSC, and TOS tended to be higher for contralateral stimuli than for ipsilateral stimuli, all three regions exhibited position-invariant adaptation, insofar as the magnitude of adaptation did not depend on whether stimuli were repeated in the same or opposite hemifields. In contrast, object-selective regions showed significantly greater adaptation when objects were repeated in the same hemifield. These results suggest that neuronal receptive fields (RFs) in scene-selective regions span the vertical meridian, whereas RFs in object-selective regions do not. The PPA, RSC, and TOS may support scene perception and navigation by maintaining stable representations of large-scale features of the visual environment that are insensitive to the shifts in retinal stimulation that occur frequently during natural vision.

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