Structure Of Corona Research Articles

Recent Advances in Simulation Studies on the Protein Corona

When flowing through the blood stream, drug carriers such as nanoparticles encounter hundreds of plasma proteins, forming a protein layer on the nanoparticle surface, known as the “protein corona”. Since the protein corona influences the size, shape, and surface properties of nanoparticles, it can modulate their circulating lifetime, cytotoxicity, and targeting efficiency. Therefore, understanding the mechanism of protein corona formation at the atomic scale is crucial, which has become possible due to advances in computer power and simulation methodologies. This review covers the following topics: (1) the structure, dynamics, and composition of protein corona on nanoparticles; (2) the effects of protein concentration and ionic strength on protein corona formation; (3) the effects of particle size, morphology, and surface properties on corona formation; (4) the interactions among lipids, membranes, and nanoparticles with the protein corona. For each topic, mesoscale, coarse-grained, and all-atom molecular dynamics simulations since 2020 are discussed. These simulations not only successfully reproduce experimental observations but also provide physical insights into the protein corona formation. In particular, these simulation findings can be applied to manipulate the formation of a protein corona that can target specific cells, aiding in the rational design of nanomedicines for drug delivery applications.

Nested active regions anchor the heliospheric current sheet and stall the reversal of the coronal magnetic field

During the solar cycle, the Sun's magnetic field polarity reverses due to the emergence, cancellation, and advection of magnetic flux towards the rotational poles. Flux emergence events occasionally cluster together, although it is unclear if this is due to the underlying solar dynamo or simply by chance. Regardless of the cause, we aim to characterise how the reversal of the Sun's magnetic field and the structure of the solar corona are influenced by nested flux emergence. From the spherical harmonic decomposition of the Sun's photospheric magnetic field, we identified times when the reversal of the dipole component stalls for several solar rotations. Using observations from sunspot cycle 23 to present, we located the nested active regions responsible for each stalling and explored their impact on the coronal magnetic field using potential field source surface extrapolations. Nested flux emergence has a more significant impact on the topology of the coronal magnetic field than isolated emergences as it produces a coherent (low spherical harmonic order) contribution to the photospheric magnetic field. The heliospheric current sheet, which separates oppositely directed coronal magnetic fields, can become anchored above nested active regions due to the formation of strong opposing magnetic fluxes. Further flux emergence, cancellation, differential rotation, and diffusion, then effectively advects the heliospheric current sheet and shifts the dipole axis. Nested flux emergence can restrict the evolution of the heliospheric current sheet and impede the reversal of the coronal magnetic field. The sources of the solar wind can be more consistently identified around nested active regions because the magnetic field topology remains self-similar for multiple solar rotations. This highlights the importance of identifying and tracking nested active regions to guide the remote-sensing observations of modern heliophysics missions.

The thermodynamic response of heating at coronal null points

ABSTRACT Magnetic null points are an important aspect of the magnetic field structure of the solar corona and can be sites of enhanced dissipation. This paper uses analytical and numerical models to investigate the plasma structure around a heated null. It is shown that the temperature profile not only differs significantly from that in a uniform field, but also that the profile depends significantly on the spatial structure of the heating. Field lines close to the separatrices and the null point have higher temperatures than a uniform field for the same heating input. The dependence of the results near the null on both the ratio of perpendicular to parallel conduction, and numerical resolution is also explored. The comparison between analytic and numerical solutions also provides a useful benchmark to compare MHD codes with anisotropic thermal conduction.

A Review for Uncovering the "Protein-Nanoparticle Alliance": Implications of the Protein Corona for Biomedical Applications.

Understanding both the physicochemical and biological interactions of nanoparticles is mandatory for the biomedical application of nanomaterials. By binding proteins, nanoparticles acquire new surface identities in biological fluids, the protein corona. Various studies have revealed the dynamic structure and nano-bio interactions of the protein corona. The binding of proteins not only imparts new surface identities to nanoparticles in biological fluids but also significantly influences their bioactivity, stability, and targeting specificity. Interestingly, recent endeavors have been undertaken to harness the potential of the protein corona instead of evading its presence. Exploitation of this 'protein-nanoparticle alliance' has significant potential to change the field of nanomedicine. Here, we present a thorough examination of the latest research on protein corona, encompassing its formation, dynamics, recent developments, and diverse bioapplications. Furthermore, we also aim to explore the interactions at the nano-bio interface, paving the way for innovative strategies to advance the application potential of the protein corona. By addressing challenges and promises in controlling protein corona formation, this review provides insights into the evolving landscape of the 'protein-nanoparticle alliance' and highlights emerging.

Local models of two-temperature accretion disc coronae – I. Structure, outflows, and energetics

ABSTRACT We use local stratified shearing-box simulations to elucidate the impact of two-temperature thermodynamics on the thermal structure of coronae in radiatively efficient accretion flows. Rather than treating the coronal plasma as an isothermal fluid, we use a simple, parametrized cooling function that models the collisional transfer of energy from the ions to the rapidly cooling leptons. Two-temperature models naturally form temperature inversions, with a hot, magnetically dominated corona surrounding a cold disc. Simulations with net vertical flux (NF) magnetic fields launch powerful magnetocentrifugal winds that would enhance accretion in a global system. The outflow rates are much better converged with increasing box height than analogous isothermal simulations, suggesting that the winds into two-temperature coronae may be sufficiently strong to evaporate a thin disc and form a radiatively inefficient accretion flow under some conditions. We find evidence for multiphase structure in the corona, with broad density and temperature distributions, and we propose criteria for the formation of a multiphase corona. The fraction of cooling in the surface layers of the disc is substantially larger for NF fields compared to zero net-flux configurations, with moderate NF simulations radiating ≳30 per cent of the flow’s total luminosity above two mid-plane scale heights. Our work shows that NF fields may efficiently power the coronae of luminous Seyfert galaxies and quasars, providing compelling motivation for future studies of the heating mechanisms available to NF fields and the interplay of radiation with two-temperature thermodynamics.

In situ study of structural changes: Exploring the mechanism of protein corona transition from soft to hard

HypothesisThe process of protein corona changes has been widely believed to follow the Vroman effect, while protein structural change during the process is rarely reported, due to the lack of analytical methods. In-situ interpretation for protein structural change is critical to processes such as the recognition and transport of nanomaterials. ExperimentsMolecular dynamics (MD) simulation was used to predict the deflection and twist of the protein tertiary structure. The structural changes of the surface protein corona during the interaction of nanoparticles (NPs) with lipid bilayer were probed in situ and real-time by sum frequency generation (SFG) spectroscopy. FindingsThe ring tertiary structure of the protein corona is altered from vertical to horizontal on particle surface, a process of the soft-to-hard structural transition, which is contributed by the hydrogen bonding force between the protein and water molecules. The negatively charged protein corona can induce the redistribution of interfacial charge, leading to a more stable hydrogen bond network of the interfacial water. Our findings suggest that the structural change from flexible to rigid is a crucial process in the soft-to-hard transition of the protein corona, which will be a beneficial supplement to the Vroman effect of protein adsorption.

Interchange reconnection dynamics in a solar coronal pseudo-streamer

Context.The generation of the slow solar wind remains an open problem in heliophysics. One of the current theories among those aimed at explaining the injection of coronal plasma in the interplanetary medium is based on interchange reconnection. It assumes that the exchange of magnetic connectivity between closed and open fields allows the injection of coronal plasma in the interplanetary medium to travel along the newly reconnected open field. However, the exact mechanism underlying this effect is still poorly understood.Aims.Our objective is to study this scenario in a particular magnetic structure of the solar corona: a pseudo-streamer. This topological structure lies at the interface between open and closed magnetic field and is thought to be involved in the generation of the slow solar wind.Methods.We performed innovative 3D magnetohydrodynamic (MHD) simulations of the solar corona with a pseudo-streamer, using the Adaptively Refined MHD Solver (ARMS). By perturbing the quasi-steady ambient state with a simple photospheric, large-scale velocity flow, we were able to generate a complex dynamics of the open-and-closed boundary of the pseudo-streamer. We studied the evolution of the connectivity of numerous field lines to understand its precise dynamics.Results.We witnessed different scenarios of opening of the magnetic field initially closed under the pseudo-streamer: one-step interchange reconnection dynamics, along with more complex scenarios, including a coupling between pseudo-streamer and helmet streamer, as well as back-and-forth reconnections between open and closed connectivity domains. Finally, our analysis revealed large-scale motions of a newly opened magnetic field high in the corona that may be explained by slipping reconnection.Conclusions.By introducing a new analysis method for the magnetic connectivity evolution based on distinct closed-field domains, this study provides an understanding of the precise dynamics underway during the opening of a closed field, which enables the injection of closed-field, coronal plasma in the interplanetary medium. Further studies shall provide synthetic observations for these diverse outgoing flows, which could be measured by Parker Solar Probe and Solar Orbiter.

Long-term forcing of the Sun’s coronal field, open flux, and cosmic ray modulation potential during grand minima, maxima, and regular activity phases by the solar dynamo mechanism

ABSTRACT Magnetic fields generated in the Sun’s interior by the dynamo mechanism drive solar activity over a range of time-scales. Direct sunspot observations exist for a few centuries; reconstructed variations based on cosmogenic isotopes in the solar open flux and cosmic ray flux exist over thousands of years. While such reconstructions indicate the presence of extreme solar activity fluctuations in the past, causal links between millennia scale dynamo activity, consequent coronal field, solar wind, open flux and cosmic ray flux variations remain elusive; a lack of coronal field observations compounds this issue. By utilizing a stochastically forced solar dynamo model and potential field source surface extrapolation, we perform long-term simulations to illuminate how dynamo generated magnetic fields govern the structure of the solar corona and the state of the heliosphere – as indicated by variations in the open flux and cosmic ray modulation potential. We establish differences in the nature of the large-scale structuring of the solar corona during grand maximum, minimum, and regular solar activity phases and simulate how the open flux and cosmic ray modulation potential vary across these different phases of activity. We demonstrate that the power spectrum of simulated and observationally reconstructed solar open flux time series are consistent with each other. Our study provides the theoretical foundation for interpreting long-term solar cycle variations inferred from cosmogenic isotope based reconstructions and establishes causality between solar internal variations to the forcing of the state of the heliosphere.

Formation mechanism for stable system of nanoparticle/protein corona and phospholipid membrane

In the physiological environment, nanoparticles (NPs) interact with proteins to form a protein-rich layer on the surface which is called "protein corona". Understanding and analyzing the formation process of protein corona and protein corona-nanoparticles is of great significance for biological related nano research. Many separation techniques have been used to analyze the composition of protein corona, but in situ analysis of protein corona is still absent. With the development of detection technology, sum frequency generation (SFG) is an effective instrument to analyze the surface protein structure and dynamic changes of protein corona in situ. In this work the molecular mechanism and surface structure effect of the interaction between nanoparticles with surface protein corona (S-NPP) and phospholipid membrane were studied. When S-NPP interacts with phospholipid membrane, the bond affinity network formed by the binding water can stabilize S-NPP around the lipid bilayer. In this process, S-NPP can be found wrapped in the hydration shell. This ultimately leads to a more moderate interaction between particles and phospholipid membrane.

A mutually embedded perception model for solar corona

ABSTRACTThis paper proposes a new mutually embedded perception model (MEPM) based on the 3D magnetohydrodynamic (MHD) equations of the solar wind plasma to reconstruct the structure of the solar corona. The goal is to embed the physics-based information and gradient into solar wind parameters data through the neural network and leverage the adaptive procedures to improve solution accuracy. The loss term proportional to the divergence is directly introduced to force a divergence-free solution. The established MEPM displays almost the same results as the exact solution for an artificial 3D analytic problem and the Parker solar wind for 1D steady Parker flow with the corresponding boundary conditions. The MEPM can well capture the solar coronal leading structures, recover the results of the traditional numerical schemes, and be consistent with the observations with CR 2068 as an example. When supplementary data (from the results of the MHD simulation or empirical models) are used, the modeled results improve. This implies that in situ satellite observations as supplementary data can be incorporated into the model in the same way.

Impact of pH on the Formation and Properties of Whey Protein Coronas around TiO2 Nanoparticles.

In aqueous media, titanium dioxide (TiO2) nanoparticles can interact with proteins in their environment and form a protein corona. The pH of the aqueous media affects the structure and properties of the protein corona, and currently there is a lack of understanding of the effects of pH on the characteristics of protein coronas. In this study, we examined the impact of pH (2-11) on the structural and physicochemical properties of whey protein coronas formed around TiO2 nanoparticles. The pH of the solution influenced the structure of whey protein molecules, especially around their isoelectric point. Thermogravimetric and quartz crystal microbalance analyses showed that the adsorption capacity of the whey proteins was the largest at their isoelectric points and the lowest under highly acidic or alkaline conditions. The majority of the proteins were tightly bound to the nanoparticle surfaces, forming a hard corona. The influence of solution pH on protein corona properties was mainly attributed to its impact on the electrostatic forces in the system, which impacted the protein conformation and interactions. This study provides useful insights into the influence of pH on the formation and properties of protein coronas around inorganic nanoparticles, which may be important for understanding the gastrointestinal and environmental fates.

Tackling the Unique Challenges of Low-frequency Solar Polarimetry with the Square Kilometre Array Low Precursor: Pipeline Implementation

The dynamics and the structure of the solar corona are determined by its magnetic field. Measuring coronal magnetic fields is, however, extremely hard. The polarization of low-frequency radio emissions has long been recognized as one of the few effective observational probes of magnetic fields in the mid and high corona. However, the extreme intrinsic variability of this emission, the limited ability of most of the available existing instrumentation (until recently) to capture it, and the technical challenges involved have all contributed to its use being severely limited. The high dynamic-range spectropolarimetric snapshot imaging capability that is needed for radio coronal magnetography is now within reach. This has been enabled by the confluence of data from the Murchison Widefield Array (MWA), a Square Kilometre Array (SKA) precursor, and our unsupervised and robust polarization calibration and imaging software pipeline dedicated to the Sun—Polarimetry using the Automated Imaging Routine for Compact Arrays of the Radio Sun (P-AIRCARS). Here, we present the architecture and implementation details of P-AIRCARS. Although the present implementation of P-AIRCARS is tuned to the MWA, the algorithm itself can easily be adapted for future arrays, such as SKA1-Low. We hope and expect that P-AIRCARS will enable exciting new science with instruments like the MWA, and that it will encourage the wider use of radio imaging in the larger solar physics community.

Fast and Dynamic Mapping of the Protein Corona on Nanoparticle Surfaces by Photocatalytic Proximity Labeling.

Protein corona broadly affects the delivery of nanomedicines in vivo. Although it has been widely studied by multiple strategies like centrifugal sedimentation, the rapidly forming mechanism and the dynamic structure of the protein corona at the seconds level remains challenging. Here, a photocatalytic proximity labeling technology in nanoparticles (nano-PPL) is developed. By fabricating a "core-shell" nanoparticle co-loaded with chlorin e6 catalyst and biotin-phenol probe, nano-PPL technology is validated for the rapid and precise labeling of corona proteins in situ. Nano-PPL significantly improves the temporal resolution of nano-protein interactions to 5 s duration compared with the classical centrifugation method (>30 s duration). Furthermore, nano-PPL achieves the fast and dynamic mapping of the protein corona on anionic and cationic nanoparticles, respectively. Finally, nano-PPL is deployed to verify the effect of the rapidly formed protein corona on the initial interaction of nanoparticles with cells. These findings highlight a significant methodological advance toward nano-protein interactions in the delivery of nanomedicines in vivo.

Differential cellular responses to FDA-approved nanomedicines: an exploration of albumin-based nanocarriers and liposomes in protein corona formation.

Albumin nanoparticles (NPs) and PEGylated liposomes have garnered tremendous interest as therapeutic drug carriers due to their unique physicochemical properties. These unique properties also have significant effects on the composition and structure of the protein corona formed around these NPs in a biological environment. Herein, protein corona formation on albumin NPs and liposomes was simultaneously evaluated through in vitro and simulation studies. The sizes of both types of NPs increased with more negatively charged interfaces upon being introduced into fetal bovine serum. Gel electrophoresis and label-free quantitative proteomics were performed to identify proteins recruited to the hard corona, and fewer proteins were found in albumin NPs than in liposomes, which is in accordance with isothermal titration calorimetry. The cellular uptake efficiency of the two NPs significantly differed in different serum concentrations, which was further scrutinized by loading an anticancer compound into albumin NPs. The presence of the hard protein corona increased the cellular uptake of albumin NPs in comparison with liposomes. In our simulation study, a specific receptor present in the membrane was greatly attracted to the albumin-apolipoprotein E complex. Overall, this study not only evaluated protein corona formation on albumin NPs, but also made promising advancements toward albumin- and liposome-based therapeutic systems.

Tetrahomo corona[4]arene-based spirophanes: synthesis, structure, and properties.

In contrast to a plethora of macrocyclic and cage compounds, spirophanes have remained largely unexplored. We report herein the construction, structure and properties of unprecedented tetrahomo corona[4]arene-based ditopic and tritopic macrocycles of spiro structures. Synthesis was conveniently achieved by means of an efficient SNAr reaction from simple and commercially available starting materials. Racemic samples were resolved into enantiopure chiral tetrahomo i-corona[4]arenes, spirophanes and bispirophanes which show interesting chiroptical properties. The acquired electron-deficient macrocyclic compounds were found to adopt unique conformational structures and to form distinct complexes with TTF in the solid state. Our study provides a new opportunity to develop multitopic macrocycles of different topologies which have potential applications in supramolecular chemistry.

SULIS: A coronal magnetism explorer for ESA’s Voyage 2050

Magnetism dominates the structure and dynamics of the solar corona. To understand the true nature of the solar corona and the long-standing coronal heating problem requires measuring the vector magnetic field of the corona at a sufficiently high resolution (spatially and temporally) across a large Field-of-View (FOV). Despite the importance of the magnetic field in the physics of the corona and despite the tremendous progress made recently in the remote sensing of solar magnetic fields, reliable measurements of the coronal magnetic field strength and orientation do not exist. This is largely due to the weakness of coronal magnetic fields, previously estimated to be on the order of 1-10 G, and the difficulty associated with observing the extremely faint solar corona emission. With the Solar cUbesats for Linked Imaging Spectro-polarimetry (SULIS) mission, we plan to finally observe, in detail and over the long-term, uninterrupted measurements of the coronal magnetic vector field using a new and very affordable instrument design concept. This will be profoundly important in the study of local atmospheric coronal heating processes, as well as in measuring the nature of magnetic clouds, in particular, within geoeffective Earth-bound Coronal Mass Ejections (CMEs) for more accurate forecasting of severe space weather activity.

Coronal spectral diagnostics: The coronal solar magnetism observatory (COSMO)

The Need: Understanding and predicting the major phenomena taking place in the solar corona, such as flares and Coronal Mass Ejections (CMEs), the heating and evolution of the solar atmosphere, and the acceleration of the solar wind, are fundamental challenges to predict our own star. These challenges are related to the solar magnetism and to the physical properties of solar plasmas: meeting them requires two types of measurements: (A) Spectrally resolved, simultaneous observations of the entire corona in multiple spectral lines emitted by chromospheric to hot coronal plasmas at high spatial resolution and cadence for long periods of time; and (B) Coronal magnetic field measurements.The Problem: The current fleet of space instruments suffers from three main limitations: (A) EUV narrow-band imagers provide simultaneous 2D images of the corona, but lack adequate plasma diagnostic capabilities; (B) High-resolution EUV spectrometers have the required diagnostic potential, but their narrow field of view prevents a continuous and simultaneous coverage of the entire corona. (C) No current instrument can measure the global coronal magnetic field.The Solution: Visible to near-IR coronagraphs coupled to tunable filters combine the strengths of both EUV high resolution spectrometers and EUV imagers in one single instrument by 1) providing 2D images of the whole field of view at a single wavelength; 2) spectrally resolving individual lines near-simultaneously across the entire field of view, and 3) measuring the magnetic field through polarimetry. The proposed Coronal Solar Magnetism Observatory (COSMO) visible to near-IR coronagraph would allow the measurement of: (A) simultaneous plasma thermal structure of the whole solar corona and CMEs; (B) plasma velocity vector; and (C) coronal magnetic field. The technology behind visible/near-IR coronagraphs coupled to tunable filters is mature; ground-based implementation of such instruments would provide long-term, easily-upgradable data sets.

Impact of Vroman’s Effect on Pharmacodynamics and Pharmacokinetics on Nanoparticulate Drug Delivery Systems

Published on: October 2022Journal of Young Pharmacists, 2022; 14(4):355-358Review Article | doi:10.5530/jyp.2022.14.72 Authors:Chinthaginjala Haranath1,*, Krishnam Sai Vamsi1, Yousef AM Qarmout1, Hindustan Abdul Ahad2, Samuluru Chandana31Department of Pharmaceutics, Raghavendra Institute of Pharmaceutical Education and Research (RIPER)- Autonomous, Ananthapuramu, Andhra Pradesh, INDIA.2Department of Industrial Pharmacy, Raghavendra Institute of Pharmaceutical Education and Research (RIPER)- Autonomous, Ananthapuramu, Andhra Pradesh, INDIA.3Department of Quality Assurance, Raghavendra Institute of Pharmaceutical Education and Research (RIPER)- Autonomous, Ananthapuramu, Andhra Pradesh, INDIA. Abstract:Nanoparticle drug delivery can produce a unique pharmacokinetic and pharmacodynamic effect and unveiled better safety in vivo and in vitro toxicity profiles when compared with conventional drugs. In 1960, Vroman revealed that competitive protein exchange is a general phenomenon that occurs when a protein mixture adsorbs to a surface is called ‘Vroman’s effect’ which is responsible for the fate of the nanoparticles. The development and formation of protein corona on nanoparticles is due to the adsorption of proteins on the surface. It is vital in specific targeting and alter the size and composition of the nanoparticle. The entropy-driven binding manages this adsorption of protein on the surface. Binding of polyethylene glycol to the nanoparticles decreases the non-specific binding and increases the targeting of tissue via enhanced permeability and retention effect. An individual disease state and components in biofluids can modify the structure and shape of protein corona on nanoparticles. By label-free transducers, we can detect targets using Vroman’s effect. The biological identification of nanoparticles can lead to deleterious consequences, such as immunotoxicity, due to the formation of the protein corona.Keywords: Vromans effect, Nanoparticles, Protein corona, Disease state, Biofluids.

The high energy spectrum of Proxima Centauri simultaneously observed at X-ray and FUV wavelengths

The M dwarf Proxima Centauri, the Sun’s closest stellar neighbour, is known to be magnetically active and it hosts a likely Earth-like planet in its habitable zone. High-energy radiation from the host star can significantly alter planetary atmospheres in close orbits. Frequent flaring may drive radiation-induced effects such as rapid atmospheric escape and photochemical changes. Therefore, understanding the characteristics of stellar radiation by understanding the properties of the emitting plasma is of paramount importance for a proper assessment of the conditions on Proxima Centauri b and exoplanets around M dwarfs in general. This work determines the temperature structure of the coronal and transition region plasma of Proxima Centauri from simultaneous X-ray and far-ultraviolet (FUV) observations. The differential emission measure distribution (DEM) was constructed for flaring and quiescent periods by analysing optically thin X-ray and FUV emission lines. Four X-ray observations of Proxima Centauri were conducted by the LETGS instrument on board of the Chandra X-ray Observatory and four FUV observations were carried out using the STIS spectrograph on board the Hubble Space Telescope. From the X-ray light curves, we determined a variation of the quiescent count rate by a factor of two within 20% of the stellar rotation period. To obtain the DEM, 18 optically thin emission lines were analysed (12 X-ray and six FUV). The flare fluxes differ from the quiescence fluxes by factors of 4–20 (FUV) and 1–30 (X-ray). The temperature structure of the stellar corona and transition region was determined for both the quiescence and flaring state by fitting the DEM(T) with Chebyshev polynomials for a temperature range log T = 4.25–8. Compared to quiescence, the emission measure increases during flares for temperatures below 0.3 MK (FUV dominated region) and beyond 3.6 MK (X-ray dominated region). The reconstructed DEM shape provides acceptable line flux predictions compared to the measured values. Using the DEM we provide synthetic spectra at 1–1700 Å, which may be considered as representative for the high-energy irradiation of Proxima Cen b during quiescent and flare periods. In future work these values can be used for planet atmosphere calculations which will ultimately provide information about how habitable Proxima Centauri b is.

Fine Structures of the Inner Solar Corona and the Associated Magnetic Topology

We present the fine structure of the inner solar corona between 1.65 and 3.0 solar radii as revealed by the STEREO-A COR1 white-light coronagraph from 2008 June 20 to July 31. The COR1 imaging data were wavelet processed to enhance the intensity contrast of coronal features. The constructed limb synoptic maps at a range of altitudes show the evolution in time and altitude of these fine structures within the streamer belt, and equatorial and polar coronal holes during this period near the solar minimum. Distinct streamer-stalk structures are seen embedded within a diffuse background of the helmet streamer belt, which are preserved as they extend to higher heights. Pseudostreamers are also seen as multiple stalk structures, which also continue to higher heights. Various polar plume structures are seen to last from hours to days. Similar plume structures are also seen within the corona subtended by equatorial coronal holes. We compare the COR1 maps to that of the magnetic topology revealed by the modeled squashing factors, and discuss the relation between the two types of maps and its implications in the context of solar wind formation.