Variability of flow velocity induced by Dongsam Seawater Stream Floodgate installation

The Dongsam seawater stream on a reclaimed land flows by tidal forcing. The flow in generally slow, especially in the central portion of the stream because the outflow and inflow each occurs at both ends of the stream simultaneously. As a result, sediments accmulate constantly with the deteorating water quality. In this study, field observation was conducted using Aquadrifter and Aquadopp and analyzed for the analysis of the flow velocity in the stream. The computational fluid dynamics (CFD) modeling was run with and without Seawater Stream Floodgate to predict the variability of the flow. The flow velocity of the Dongsam Seawater Stream was recorded in the range of 0.01 ~ 0.13 m/s, and the tidal range was within 1.0 m. According to the simulation, the flow velocity could increase remarkably with two floodgates used to force the stream to flow unidirectionally (toward Korea Maritime & Ocean University). The flow velocity change rate at each point is recorded -97 ~ 638% at P1 (front of Malfunction Floodgate near Busan Int. Cruise Terminal), -89 ~ 659% at P2 (back of Malfunction Floodgate near Busan Int. Cruise Terminal), -100 ~ 1198% at P3 (central channel), and at P4 (toward Korea Maritime & Ocean University) was -100 to 1163%, and Case III-a showed the largest flow velocity rate increase in the central part. Therefore, if two Floodgates are installed and flowed out toward Korea Maritime & Ocean University, the flow velocity rate of the Stream can be increased.

The cellular environment shapes the nuclear pore complex architecture

Nuclear pore complexes (NPCs) create large conduits for cargo transport between the nucleus and cytoplasm across the nuclear envelope (NE)1–3. These multi-megadalton structures are composed of about thirty different nucleoporins that are distributed in three main substructures (the inner, cytoplasmic and nucleoplasmic rings) around the central transport channel4–6. Here we use cryo-electron tomography on DLD-1 cells that were prepared using cryo-focused-ion-beam milling to generate a structural model for the human NPC in its native environment. We show that—compared with previous human NPC models obtained from purified NEs—the inner ring in our model is substantially wider; the volume of the central channel is increased by 75% and the nucleoplasmic and cytoplasmic rings are reorganized. Moreover, the NPC membrane exhibits asymmetry around the inner-ring complex. Using targeted degradation of Nup96, a scaffold nucleoporin of the cytoplasmic and nucleoplasmic rings, we observe the interdependence of each ring in modulating the central channel and maintaining membrane asymmetry. Our findings highlight the inherent flexibility of the NPC and suggest that the cellular environment has a considerable influence on NPC dimensions and architecture.

Minimizing the Negative Effects of Coolant Channels on the Torsional and Torsional-Axial Stiffness of Drills

Coolant channels allow internal coolant delivery to the cutting region and significantly improve drilling, but these channels also reduce the torsional and torsional-axial stiffness of the drills. Such a reduction in stiffness can degrade the quality of the drilled holes. The evacuation of cutting chips and the delivery of the cutting fluid put strict geometrical restrictions on the cross-section design of the drill. This necessitates careful selection and optimization of features such as the geometry of the coolant channels. This paper presents a new method that uses Prandtl’s stress function to predict the torsional and torsional-axial stiffness values. Using this method drills with one central channel are compared to those with two eccentric coolant channels, which shows that with the same cross-section area, the reduction of axial and torsional-axial stiffness is notably smaller for the design with two eccentric channels compared to a single central channel. The stress function method is further used to select the appropriate location of the eccentric coolant channels to minimize the loss of torsional and torsional-axial stiffness. These results are verified by comparison to the results of three-dimensional finite element analyses.

Lower Cretaceous Dinosaur Trackways Exposed by Water Erosion in Sichuan Province, China

A newly discovered saurischian dominated tracksite in the Lower Cretaceous Jiaguan Formation in southeastern Sichuan province reveals 13 sauropod trackway segments representing ichnogenus Brontopodus and three theropod trackways. This is a typical Type 1 Jiaguan Formation deposit dominated by tetrapod tracks with no significant tetrapod body fossils. The tracks occur in a river channel exposure of feldspathic quartz sandstone about 20–25 m wide and ~ 60 m long. The trackways are exposed on both banks but eroded away in the central channel area. The sauropod tracks represent relatively small animals with pes print lengths ranging from 24.5 cm to 33.9 cm. The theropod trackways include a large example (footprint length 46.5 cm with metatarsal traces) and two smaller parallel trackways with footprint lengths less than 20 cm. The author also discussed the erosion of tracks and trackways by water erosion, especially their morphological changes.

A Novel Approach to Model Threshold Voltage and Subthreshold Current of Graded-Doped Junctionless-Gate-All-Around (GD-JL-GAA) MOSFETs

This present article interprets the analytical models of central channel potential, the threshold voltage, and subthreshold current for Graded-Doped Junctionless-Gate-All-Around (GD-JL-GAA) MOSFETs. The parabolic approximation equation with appropriate boundary conditions has been adopted to solve the 2D Poisson’s equation for determining the central channel potential. The minimum channel potential is obtained by potential channel expression, and it is utilized to determine the threshold voltage and subthreshold current by using the Drift-Diffusion method. The behaviour of GD-JL-GAA MOSFETs has been examined by varying physical device parameters such as doping concentration (NDn), channel thickness (tsi), oxide thickness (tox), and channel length ratio (L1 : L2). The mathematical analysis shows that the nominal gate leakage current in GD-JL-GAA MOSFETs due to high graded abrupt junction inside the channel region. The analytical model results have been verified with simulation data extracted from a TCAD simulator.

Hypernormalization, Collaborative Analytics, and the Making of “American Stiob”

This chapter reviews a collaboration that chronicles how an article project comes into being. It provides an analysis of how a collaborative process impacts the conceptual tools and analytical process that have been developed. It also mentions anthropological insight that often has meager beginnings — a hunch, a slight puzzling, an observation or moment of recognition that happens to ramify. The chapter cites that Jon Stewart's The Daily Show had emerged as a rare channel of political insight and sincerity despite being broadcast on the Comedy Central channel and was becoming a go-to news source, especially for many younger Americans. It discusses academic scholarship on The Colbert Report, which revealed that viewers from across the political spectrum found the show funny and thought that Colbert's political sympathies corresponded to their own.

Mycobacterium smegmatis expands across surfaces using hydraulic sliding

Mycobacterium smegmatis spreads over soft agar surfaces by sliding motility, a form of passive motility in which growth and reduction of surface adhesion enable the bacteria to push each other outwards. Hence, sliding motility is mostly associated with round colonies. However, M. smegmatis sliding colonies can also produce long, pointed dendrites. Round sliding colonies were readily reproduced, but our non-round colonies were different from those seen previously. The latter (named digitate colonies) had centimetre-long linear protrusions, containing a central channel filled with a free-flowing suspension of M. smegmatis and solid aggregates. Digitate colonies had both a surface pellicle and an inner biofilm component surrounding a central channel, which sat in a cleft in the agar. Time-lapse microscopy showed that the expansion of the fluid-filled channel enabled the lengthwise extension of the protrusions without any perceptible growth of the bacteria taking place. These observations represent a novel type of sliding motility, named hydraulic sliding, associated with a specialised colony structure and the apparent generation of force by expansion of a liquid core. As this structure requires pellicle formation without an initial liquid culture it implies the presence of an unstudied mycobacterial behaviour that may be important for colonisation and virulence.Originality-Significance StatementThis study is the first to identify a new form of passive motility in the mycobacteria; hydraulic sliding, in which liquid expansion is the cause of motility. This form of motility has so far never been described in bacteria. The study also reveals new ways mycobacteria can form biofilms and colonize complex three-dimensional substrates, aspects of mycobacterial biology that are important for infection, pathogenesis and vaccine development.Author SummaryMycobacterium smegmatis is used as a non-pathogenic model organism for pathogenic mycobacteria. During growth, M. smegmatis can move passively over soft agar surfaces by a process called sliding motility, whereby colony growth directly pushes cells outwards. Although passive, sliding motility is believed to be important in allowing bacteria to colonise surfaces. Sliding motility however does not fully account for how M. smegmatis produces dendritic colonies. We attempted to generate dendritic colonies but found instead that the cells produced colonies that had larger protrusions radiating from them (digitate colonies). Digitate colonies are a previously unobserved phenomenon, in that the bacteria create a biofilm-lined, fluid-filled, pellicle-covered, deep cleft in the agar and move across the surface by the expansion of the contained liquid core of the protrusions. Given the new structure and the new mechanism of expansion we have termed this set of behaviours hydraulic sliding. These observations are important as it is a new variation in the way bacteria can move, generate biofilms (notably mycobacterial pellicle) and colonize complex three-dimensional substrates.

Epigallocatechin-Gallate and Theaflavin-Gallate Interaction in SARS CoV-2 Spike-Protein Central-Channel with Reference to the Hydroxychloroquine Interaction: Bioinformatics and Molecular Docking Study

SARS CoV-2 or COVID-19 pandemic global-outbreak created the most unstable situation of human health-economy. Last two decades different parts of the word experienced smaller or bigger outbreak related to human-coronaviruses. The spike-glycoproteins of the COVID-19 (similar to SARS-CoV) attach to the angiotensin-converting-enzyme (ACE-2) and transit over a stabilized open-state for the viral-internalization to the host-cells and propagate with great efficacy. Higher rate of mutability makes this virus unpredictable/less-sensitive to the protein/nucleic-acid based-drugs. In this emergent situation, drug-induced destabilization of spike-binding to RBD could be a good strategy. In the current study we demonstrated by Bioinformatics (CASTp: Computed-Atlas-of-Surface-Topography, PyMol: molecular-visualization) and Molecular docking (PatchDock) experiments that tea flavonoids catechin-products mainly EGCG or other like theaflavin gallate demonstrated higher Atomic Contact Energy (ACE), surface area and more amino-acid interactions than hydroxychloroquine (HCQ) during binding in the central channel of the spike-protein. Moreover, out of three distinct binding-sites (I, II and III) of spike core when HCQ binds only with site III (farthest from the vCoV-RBD of ACE2 contact), EGCG and TG bind all three sites. As because site I and II is in closer contact with open state location and viral-host contact area so these drugs might have significant effects. Taking into account the toxicity/side-effects by CQ/HCQ, present drugs may be important. Our laboratory is working on tea flavonoids and other phytochemicals in the protection from toxicity, DNA/mitochondrial damage, inflammation etc. The present data might be helpful for further analysis of flavonoids in this emergent pandemic situation.