Is COVID-19 Gender-sensitive? Mukherjee, Shreya; Pahan, Kalipada
Journal of neuroimmune pharmacology,
03/2021, Volume:
16, Issue:
1
Journal Article
Peer reviewed
Open access
While clinical characteristics exhibit that susceptibility to COVID-19 infection is equally likely between males and females, clinical outcomes show that males experience both a higher severity and ...fatality for COVID-19 infection than females. This review examines the evidence for these sex and gender differences and aims to illustrate possible mechanisms behind such sensitivity. Successful entry of SARS-CoV-2 into the body is dependent on the angiotensin-converting enzyme 2 (ACE2) receptor and the transmembrane protease serine 2 (TMPRSS2). Thus, sex-based differences in the expression of the ACE2 receptor and TMPRSS2 may explain the disparities in COVID-19 severity and fatality. Furthermore, these disparities may also be attributed to sex-based difference in immunological responses. Finally, the differences in clinical outcomes of COVID-19 infections between men and women may be due to gendered differences in behaviors, such as smoking, and prevalence to comorbidities. An understanding of the sex and gender sensitivities of COVID-19 infection is a necessary component towards the creation of effective treatment options and therapies for the virus.
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Multitude of complications involved with handling hydrogen fuels has propelled many to consider instead an ammonia economy. Ammonia electrooxidation reaction (AOR) herein is discussed as a means for ...energy application either by electrochemical decomposition for onsite hydrogen generation or by direct employment of ammonia as a fuel in a direct ammonia fuel cell. The development of a robust and stable AOR catalysts are pivotal for both applications, alongside the development of a high-performing HER and ORR catalysts. Examined here are the different operating conditions for both applications and different hurdles to overcome for the catalyst development. The kinetics and mechanism of ammonia electrooxidation are elucidated to provide a foundation to better understand the issues associated with this technology and a comprehensive review on Pt-free catalysts that have been explored for AOR is presented in order to facilitate future research direction in this promising technology.
Here we report a simple Mn coordination complex with utility as a redox-sensitive MR probe. The HBET ligand stabilizes both the Mn2+ and Mn3+ oxidation states. In the presence of glutathione (GSH), ...low relaxivity MnIII-HBET is converted to high relaxivity MnII-HBET with a 3-fold increase in relaxivity, and concomitant increase in MR signal. Alternately, hydrogen peroxide can convert MnII-HBET to MnIII-HBET with a reduction in MR signal.
The laboratory synthesis of the oxygen-evolving complex (OEC) of photosystem II has been the objective of synthetic chemists since the early 1970s. However, the absence of structural information on ...the OEC has hampered these efforts. Crystallographic reports on photosystem II that have been appearing at ever-improving resolution over the past ten years have finally provided invaluable structural information on the OEC and show that it comprises a Mn₃CaO₄ distorted cubane, to which is attached a fourth, external Mn atom, and the whole unit attached to polypeptides primarily by aspartate and glutamate carboxylate groups. Such a heterometallic Mn/Ca cubane with an additional metal attached to it has been unknown in the literature. This paper reports the laboratory synthesis of such an asymmetric cubane-containing compound with a bound external metal atom, MnIV₃Ca₂O₄(O₂CBut)₈(ButCO₂H)₄(1). All peripheral ligands are carboxylate or carboxylic acid groups. Variable-temperature magnetic susceptibility data have established 1 to possess an S = 9/2 ground state. EPR spectroscopy confirms this, and the Davies electron nuclear double resonance data reveal similar hyperfine couplings to those of other MnIV species, including the OEC S₂ state. Comparison of the X-ray absorption data with those for the OEC reveal 1 to possess structural parameters that make it a close structural model of the asymmetric-cubane OEC unit. This geometric and electronic structural correspondence opens up a new front in the multidisciplinary study of the properties and function of this important biological unit.
The most significant obstacle in addressing cancer is the development of multidrug resistance during chemotherapy. Cancer cells have the ability to endure numerous cycles of traditional chemotherapy ...drugs before ultimately developing resistance to the treatment. Combining drugs is a strategy used to address the problem of multidrug resistance. Persistent challenges with synthetic drugs include catastrophic adverse reactions and other consequences. Natural compounds originating from traditional Chinese medicine are acknowledged for their minimal toxicity and possible benefits in reversing multidrug resistance induced by mainstream chemotherapeutic or targeted treatments. Cancer multidrug resistance (MDR) is an immediate clinical justification for unsatisfactory chemotherapy treatment. Cancer recurrence and metastasis are precipitated by MDR, leading to a high risk of death. The development of a unique nano-delivery method for the therapeutic management of MDR cancers has emerged as a key use of nanotechnology. Because of its significant anticancer prospective, traditional Chinese medicine (TCM)-combination therapy is an emerging treatment modality and an essential treatment option for cancer. By precisely regulating the release of medicines and delivering pharmaceuticals to cancerous cells, nano targeted drug-delivery devices offer amazing benefits and pave the way for the growth of TCM-combination therapies.
The present review examines the literature on three important topics: the mechanism of MDR in cancer chemotherapy, the role of traditional Chinese herbs and formulation in MDR treatment, and the incorporation of TCM in nanotechnology-based drug delivery systems to circumvent the limitations of traditional system. Major sources for the work include PubMed, Google Scholar, ResearchGate, Embase, and ScienceDirect. All the aspects pertaining to MDR, TCM, and nanotechnology for more than 50 years were considered, with an emphasis on the use of TCM in nano formulation, various forms of nano formulation, advances in the drug delivery system as a result of nanotechnology, and everything else in between.
As nanotechnology becomes more closely associated with TCM, the realm of practice for TCM is broadening. Furthermore, it enhances the prospects for future research and facilitates the advancement of modern Traditional Chinese Medicine (TCM). By integrating nanotechnology into a meticulously designed drug delivery system, TCM will enhance its ability to both treat and prevent diseases with even greater efficacy than previously.
This article examines nano-TCM and explores its characteristics, compositions, and relevant techniques for preparation and application in reversing MDR. In addition, a comprehensive elucidation of the key benefits of nano-TCM had been given with respect to MDR. The objective of this study was to analyze the existing body of literature on the application of nanotechnology in traditional Chinese medicine (TCM) that can be used in the treatment of MDR. The review encompasses various aspects like the development of active components for TCM, the utilization of TCM for reversing multidrug resistance (MDR), and the potential future advancements and obstacles associated with TCM-based nano combinations.
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•Segregation morphology, α’ lath size, γ and θ-Fe3C phases vary with reheat cycles.•Mechanical properties vary along built height.•Orientation of martensitic laths alters from top to ...bottom due to reheat cycles.•Contributions from individual strengthening mechanism varies along built height.
This work investigates complex heterogeneity in microstructure and mechanical properties of a low alloy martensitic steel fabricated via laser-directed energy deposition (L-DED). A multi-scale characterization starting from macro-scale optical micrography, micro-scale X-ray diffraction and electron backscatter diffraction mapping to nano-scale transmission electron microscopy was adopted to fully comprehend the microstructural heterogeneity along the build direction. Notably, the top layers of the build demonstrated enhanced mechanical properties, exhibiting hardness of around 550 HV and an ultimate tensile strength of 2 GPa, which decreased progressively towards the base. Interestingly, resurgence in strength and hardness was observed for the layers located 10 mm above the substrate. The primary solidification cycle led to the formation of untempered martensite having high strength and hardness while subsequent reheat cycles led to the alteration of these martensites, enhancing ductility at the expense of strength. Auto-tempering and carbide (Fe-C based) precipitation due to prolonged thermal exposure contributed to the increased the strength in the lower layers. Additionally, the temperature profiles during the L-DED thermal cycles were modeled and correlated with the observed phase transformations, allowing for a detailed understanding of the structure–property relationships at different heights within the build. This study provides a fundamental insight into the microstructural heterogeneities and their implications on the strengthening mechanisms in L-DED fabricated low-alloy martensitic steel.
The scanning strategy has a measurable impact on the grain size and growth direction of the produced parts in powder bed fusion. Tilting of the laser scan lines by 67° is a default procedure ...applicable to PBF machines for obtaining maximum variability in the direction of melt pools. In this work, AlSi10Mg parts were produced through direct metal laser sintering with two different scanning strategies. In the first strategy, the scanning lines were not tilted in between layers while in the second strategy, the scanning lines were tilted by 67°. The microstructures of the as-deposited alloys for the two strategies were evaluated by state-of-art characterization methods like scanning electron microscopy, electron backscatter diffraction (EBSD), X-ray computed tomography (X-ray CT), and X-ray diffraction. Monotonic tensile tests were hence conducted in both categories. Greater tensile strength was demonstrated by the specimens with no tilting of the scan lines while the specimens produced with a 67° tilt manifested greater elongation. Grain morphology characterized by EBSD studies suggested an inhomogeneity in grain size for the specimens with no tilting of the scan lines. This had primarily attributed to the early failure of the same. It was also found out that the preferred growth direction of grains in AlSi10Mg was hindered by tilting the scan lines by 67°. X-Ray CT studies and Kocks–Mecking Analysis explained the deformation and hardening behavior of both the types in the view of porosity and structural defects.
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•The Bastar cratonic margin reworked during Bhopalpatnam orogeny.•Lu-Hf chronology indicates peak metamorphism at 1721 Ma for >300 km.•Sm-Nd chronology indicates post-peak cooling to ≤650 °C at ...1683 Ma.•Early Mesoproterozoic cratonic convergence between Bastar and Eastern Dharwar.•Supports South Indian Block cratons not being part of supercontinent Columbia.
Temporal constraints on orogen initiation and duration are critical for the Paleoproterozoic reconstruction of cratons presently constituting India. Recent late Paleoproterozoic paleomagnetic pole data indicate proximity of Eastern Dharwar, Bastar and Singhbhum cratons and in view of global Mesoproterozoic-aged final Columbia assembly, reconstruction sequence of Indic cratons is critical to assess whether they constituted Columbia. The initiation time and duration of the Bhopalpatnam orogen, developed between the Eastern Dharwar and Bastar cratons, range from earliest Mesoproterozoic to Neoarchean. Therefore, in order to constrain the earliest stages of cratonic convergence and crustal thickening, the time of peak metamorphism was established on tectonites, sampled from > 300 km along newly classified longitudinal domains representative of the entire Bhopalpatnam orogen, by precise combined garnet Lu-Hf and Sm-Nd chronology of amphibolite-and granulite-facies rocks. Interpreting the Lu-Hf and Sm-Nd isochron weighted mean ages, an orogenic duration of 38 ± 19 Myr is inferred between the high-pressure amphibolite-facies through to granulite-facies event at 1721 ± 14 Ma and a post-peak cooling to ≤ 650 °C at 1683 ± 6 Ma, being the Sm-Nd garnet weighted mean age. Archean two-stage depleted mantle model ages (at 1.7 Ga) of tectonites and rotated dyke swarm orientations support the reactivation and reworking of the Paleo- to Neoarchean Bastar craton marginal rocks in response to the early Mesoproterozoic orogeny. Based on the clockwise P-T path involving an early high-pressure amphibolite-facies stage (Pmax ≥ 12 kbar at ∼ 750 °C) followed by a granulite-facies stage (Tmax ≤ 850 °C at lower pressures), we interpret the orogen to represent deeply exhumed thrust slices of the reworked Bastar craton leading edge underthrusted beneath the Eastern Dharwar craton. As paleomagnetic data indicates proximity or contiguity of Bastar and Eastern Dharwar cratons by 1.79 Ga, the Bhopalapatnam orogen could represent site of early Mesoproterozoic cratonic collision or locus of post amalgamation reactivation due to convergence.
The oxygen-evolving complex (OEC) in photosystem II (PS II) was studied in the S 0 through S 3 states using 1s2p resonant inelastic X-ray scattering spectroscopy. The spectral changes of the OEC ...during the S-state transitions are subtle, indicating that the electrons are strongly delocalized throughout the cluster. The result suggests that, in addition to the Mn ions, ligands are also playing an important role in the redox reactions. A series of MnIV coordination complexes were compared, particularly with the PS II S 3 state spectrum to understand its oxidation state. We find strong variations of the electronic structure within the series of MnIV model systems. The spectrum of the S 3 state best resembles those of the MnIV complexes Mn3 IVCa2 and saplnMn2 IV(OH)2. The current result emphasizes that the assignment of formal oxidation states alone is not sufficient for understanding the detailed electronic structural changes that govern the catalytic reaction in the OEC.
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