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Here, we report a general copper-catalyzed C(sp3) carboboration of 1,3-diynes, providing access to an array of tetra-substituted boryl enynes in a regioselective manner. All four positions of enyne can be efficiently manipulated using this methodology. The reaction was smoothly applied in the conjugation of complex bioactive molecules to the enyne scaffold. Cross-coupling reactions were carried out with boron end groups on densely substituted 1,3-enynes, opening avenues for the modular synthesis of highly functionalized enynes. Control experiments and density functional theory studies supported the proposed mechanism.

A regioselective coupling of ortho-heteroaryl anilines and 7-oxabenzonorbornadienes has been developed by leveraging free amine-directed redox-neutral Ru(II) catalysis. This protocol facilitates formal C-2 arylation of the indole moiety under mild conditions to offer valuable heterobiaryls in high yields. The reaction displays a broad substrate generality and scalability and retains efficacy in the presence of diverse pharmacophore scaffolds. Moreover, products bearing a free amine group were successfully employed in Mg(NTf2)2-catalyzed double Michael addition cascade, which led to the synthesis of intricate indole- and pyrrole-fused azaheterocycles.

Children born before 28 weeks’ gestation are at increased risk of chronic kidney disease (CKD). Urine biomarkers may shed light on mechanistic pathways and improve the ability to forecast CKD. We evaluated whether urinary biomarkers in neonates of low gestational age (GA) are associated with a reduced estimated glomerular filtration rate (eGFR) over time.

Measurement of pH in living cells is a great and decisive factor for providing an early and accurate diagnosis factor. Along with this, the multimodal transverse and longitudinal relaxivity enhancement potentiality over single modality within a single platform in the magnetic resonance imaging (MRI) field is a very challenging issue for diagnostic purposes in the biomedical field of application. Therefore, this work aims to design a versatile platform by fabricating a novel nanoprobe through holmium- and manganese-ion doping in carbon quantum dots (Ho–Mn–CQDs), which can show nearly neutral intracellular pH sensing and MRI imaging at the same time. These manufactured Ho–Mn–CQDs acted as excellent pH sensors in the near-neutral range (4.01–8.01) with the linearity between 6.01 and 8.01, which could be useful for the intracellular pH-sensing capability. An innumerable number of carboxyl and amino groups are present on the surface of the prepared nanoprobe, making it an excellent candidate for pH sensing through fluorescence intensity quenching phenomena. Cellular uptake and cell viability experiments were also executed to affirm the intracellular accepting ability of Ho–Mn–CQDs. Furthermore, with this pH-sensing quality, these Ho–Mn–CQDs are also capable of acting as T1–T2 dual modal imaging contrast agents in comparison with pristine Ho-doped and Mn-doped CQDs. The Ho–Mn–CQDs showed an increment of r1 and r2 relaxivity values simultaneously compared with only the negative contrast agent, holmium in holmium-doped CQDs, and the positive contrast agent, manganese in manganese-doped CQDs. The above-mentioned observations elucidate that its tiny size, excitation dependence of fluorescence behavior, low cytotoxicity, and dual modal contrast imaging capability make it an ideal candidate for pH monitoring in the near-neutral range and also as a dual modal MRI imaging contrast enhancement nanoprobe at the same time.

MXene-based elastomeric electromagnetic radiation shielding composites are encouraging aspirants to ensure the secure performance of stretchable and wearable electronic gadgets. However, it is a tough challenge to construct effective stretchable elastomer/MXene composites with outstanding electromagnetic radiation shielding efficiency, healing capability, thermal management, and recyclability. To simultaneously promote the multifunctional characteristics of the elastomeric composites, we prepared zinc oxide cross-linked and 1-(3-aminopropyl) imidazole (API)-grafted XNBR/MXene composites by forming continuous conductive nacre-like network via a simple two-step wet cum melt mixing strategy. Contributed by the structure, the composites show excellent shielding effectiveness of −27.4 dB (in the frequency range of 8.2–12.4 GHz) and a thermal conductivity of 1.24 W/mK while retaining the electrical conductivity of 0.5 S/cm, room temperature self-healing ability of 46.8%, and 100% recyclability with desirable stretchability and mechanical strength. Notably, the continuous conducting network remains unaffected even after reprocessing, stretching, bending, extended sunlight exposure, and chemical treatment, which validates its all-round chemical and mechanical performance. Such prolonged deformations show more than 95% retention of shielding effectiveness. Collectively, our multifunctional elastomeric composites supply a prominent directive for the establishment of high-performance elastomeric composites with outstanding shielding efficiency, self-healing ability, thermal management, recyclability, and excellent mechanical behavior.

Integration of microgrid system with the conventional grid system is an alternative solution to fulfill the power demand in a Wide Area Measurement System. However, the microgrid connected to a grid system has many challenges like voltage sag, voltage unbalancing and power loss due the Distributed Generating (DG) sources used in the microgrid. The main objective of this paper is to model a microgrid system with Distributed Generating (DG) sources and Static Synchronous Compensator (STATCOM) to enhance the voltage profile and power flow and to reduce the power loss of the system. In this paper, a real-valued Damodar Valley Corporation grid-connected microgrid system with STATCOM controller is formed with the help of Power System Analysis Toolbox software and the voltage profile and power loss of the system are observed.

Engaging allenes in transition-metal-catalyzed C–H bond activation strategy is immensely promising to access high-value scaffolds. However, such a reaction manifold remains largely elusive using cheap and sustainable ruthenium catalysis. We disclose an unprecedented ruthenium-catalyzed (4 + 2) annulation between aromatic amides and allenylphosphine oxides, furnishing NH-free isoquinolinones in high yields. This operationally simple methodology leverages weak coordination assistance, displays high selectivity, and is amenable to the late-stage functionalization of several biologically relevant motifs.

Metal core and dielectric shell nanoparticles (NPs) have garnered considerable attention for their multifaceted properties and extensive applications across diverse fields of nanoscience and nanotechnology. However, a literature gap exists regarding the impact of assembled metallic nanostar cores within a single shell, particularly concerning surface-enhanced Raman scattering (SERS) and electrochemical sensing. In this study, we have demonstrated the better performance of assemblies of gold nanostars (AuNSs) enclosed in single silica shell for SERS enhancement and electrocatalytic activity, particularly in the fields of ascorbic acid (AA) and glucose sensing. We have devised a method to isolate and passivate nanostar assemblies, ranging from 2 to 30 nanostars per assembly, with a functionalized silica (SiO2) shell, facilitating their preservation. The engineered thickness of the silica shell ensures unhindered optical measurements while elucidating the influence of multiple AuNS cores. Due to the formation of nanogaps and nanojunctions between AuNSs within assembly, we have achieved a maximum SERS enhancement factor (EF) of 1.416 × 1010for the rhodamine 6G analyte. Utilizing assembled AuNS cores within a single silica shell, we have demonstrated AA (sensitivity of 5.278 × 10–5μA μM–1cm–2) and glucose (sensitivity of 7.519 × 10–4μA μM–1cm–2) sensing via a nonenzymatic electrochemical pathway.

In the present work, we demonstrate a regioselective [2 + 2 + 2] cyclotrimerization of 1,3-diynes catalyzed by Ni0to provide hexasubstituted benzenes (HSBs). HSBs have significant applications as functional materials and pharmaceuticals. The present protocol exhibited remarkable versatility, transforming 1,3-diynes with diverse alkyl, aryl, and heterocyclic groups to the corresponding HSBs. With the help of control experiments and density functional theory (DFT), the mechanism of the reaction and the origin of regioselectivity were elucidated.

Herein we report a facile transformation of hydroxylated cucurbit[n]uril (CB[n], n= 6 and 7) to other functionality-conjugated CB[n]s by nucleophilic substitution of the hydroxyl group with a wide range of nitriles and alcohols. The reaction proceeds efficiently via generation of a superelectrophilic carbocation on the CB framework from hydroxylated CB[n]s under superacidic conditions. One of the resulting CB[n] derivatives with reactive functionality, monocarboxylated CB[7], is efficiently conjugated to an enzyme (horseradish peroxidase, HRP) by amide coupling. This provides a CB[7]-conjugated functional biomaterial (CB[7]-HRP) that selectively detects proteins labeled with a guest, adamantylammonium (AdA), based on bioorthogonal high-affinity host–guest interactions between CB[7] and AdA. We demonstrated the potential of overcoming the limitations in preparing reactive functional CB[n] derivatives, enabling the exploration of novel bioapplications of CB[n]-based host–guest chemistry with new CB[n]-conjugated functional materials.

The traditional cellular technology is not profitable to serve the sparsely populated and clustered remote rural areas because of huge network set-up cost and lesser return from low density of rural population. To provide broadband service in those remote rural areas, in this paper, we consider a TV white space (TVWS)-based hierarchical network architecture where sparsely located clustered rural pieces of user equipment (UEs) are connected to far-off central base station (CBS) via intermediate TVWS nodes, known as the pieces of customer premises equipment (CPEs) through TVWS link. The CBS has direct broadband connectivity to the Internet through optical fiber backhaul. In such a network architecture, we adopt a two-stage market model among UEs, CPEs, CBS, and propose a pricing-based Stackelberg game to distribute the total available data rate at CBS among CPEs and then to the UE. Extensive simulations have been carried out to study the data-rate distribution, and the behavior of utilities of CPE, CBS, and UE with variation of different parameters for a particular network scenario. The study of the outcome suggests that using this simple price exchange mechanism, it is possible, based on each UE's willingness-to-pay and the total available data rate, to distribute data rate optimally among the UEs where each of the network entities behaves selfishly.

Glucose regulated protein 94 kDa, Grp94, is the endoplasmic reticulum (ER) localized isoform of heat shock protein 90 (Hsp90) that is responsible for the trafficking and maturation of toll-like receptors, immunoglobulins, and integrins. As a result, Grp94 has emerged as a therapeutic target to disrupt cellular communication, adhesion, and tumor proliferation, potentially with fewer side effects compared to pan-inhibitors of all Hsp90 isoforms. Although, the N-terminal ATP binding site is highly conserved among all four Hsp90 isoforms, recent cocrystal structures of Grp94 have revealed subtle differences between Grp94 and other Hsp90 isoforms that has been exploited for the development of Grp94-selective inhibitors. In the current study, a structure-based approach has been applied to a Grp94 nonselective compound, SNX 2112, which led to the development of 8j(ACO1), a Grp94-selective inhibitor that manifests ∼440 nM affinity and >200-fold selectivity against cytosolic Hsp90 isoforms.

The breakdown of organic contaminants is a promising strategy for controlling environmental damage and treating wastewater. Even though several heterogeneous catalysts have been developed with the intention of achieving this objective, the issue of effective degradation of organic pollutants remains difficult. In this paper, we provide a simple and environmentally friendly method for making a reduced graphene oxide (RGO) nanocomposite decorated with silver nanoparticles (AgNPs). Various spectroscopic techniques were used to thoroughly characterize the nanocomposite, which was found to be composed of monodispersed AgNPs with a diameter of approximately 2–11 nm that were uniformly distributed over the surface of RGO. To ensure the versatility of the catalyst, both cationic and anionic dyes and a model 4-nitrophenol (4-NP) reduction have been tested. It has been hypothesized that the AgNPs cause oxidative breakdown of organic contaminants by facilitating electronic transitions that lead to conductive RGO nanosheets in a way that is physically possible.

The first diastereodivergent propargylic alkylation reaction is developed. This Cu(I)-catalyzed formal decarboxylative [4+2] cycloaddition between ethynyl benzoxazinanone and vinylogous aza-enamine delivers each diastereomer of tetrahydroquinoline derivatives, bearing 1,3-stereocenters, using either i-Pr-Pybox or BINAP as the ligand under otherwise identical reaction conditions. This is the first application of vinylogous aza-enamines in a transition metal-catalyzed transformation and the first example of the creation of 1,3-stereocenters in a propargylic substitution reaction.

A regio- and stereoselective allylation of N-unsubstituted anilines has been developed that explores aryl allenes as masked allyl synthons and a combination of Mg(OTf)2/HFIP as an effective proton source. The protocol is operationally simple and scalable and offers high yields of diverse p-allyl anilines bearing an olefin motif with exclusive E-geometry. The methodology was also suitable for the regioselective allylation of indole and can be advanced in a three-component reaction mode using NIS activator. The alteration of the catalytic system with TfOH resulted in the regioselective difunctionalization of allenes, which follows an allylation/hydroarylation cascade.

Within the framework of adiabatic regularization, we present a simple formalism to calculate number density and renormalized energy-momentum density of spin 1/2 particles in spatially flat FLRW spacetimes using an appropriate WKB ansatz for the adiabatic expansion for the field modes. The conformai and axial anomalies thus found are in exact agreement with those obtained from other renormalization methods. This formalism can be considered as an appropriate extension of the techniques originally introduced for scalar fields, applicable to fermions in curved space. [ABSTRACT FROM AUTHOR]

AbstractIn the 1960s, Satyajit Ray's international popularity as India's foremost film director was tempered by the criticism that his lyrical masterpieces failed to capture the fast-changing realities of his home city of Kolkata, and that they were silent on the city's steadily increasing culture of political unrest and youth unemployment.This essay argues that, contrary to this assertion, the changing city was in fact central to Ray's films in this period. This argument is based on an analysis of three of Ray's films made in the beginning, middle, and end of the 1960s which, taken together, clearly map the changing trends in the city's politics and youth culture. As with most of Ray's work, much of this discourse is personal and understated but nuanced and unambiguous at the same time.

Human Hsp90 isoforms are molecular chaperones that are often up-regulated in malignances and represent a primary target for Hsp90 inhibitors undergoing clinical evaluation. Hsp90α is a stress-inducible isoform of Hsp90 that plays a significant role in apoptosis and metastasis. Though Hsp90α is secreted into the extracellular space under metastatic conditions, its role in cancer biology is poorly understood. We report that Hsp90α associates with the Aha1 co-chaperone and found this complex to localize in secretory vesicles and at the leading edge of migrating cells. Knockdown of Hsp90α resulted in a defect in cell migration. The functional role of Hsp90α/Aha1 was studied by treating the cells with various novobiocin-based Hsp90 C-terminal inhibitors. These inhibitors disrupted the Hsp90α/Aha1 complex, caused a cytoplasmic redistribution of Hsp90α and Aha1, and decreased cell migration. Structure–function studies determined that disruption of Hsp90α/Aha1 association and inhibition of cell migration correlated with the presence of a benzamide side chain, since an acetamide substituted analog was less effective. Our results show that disruption of Hsp90α/Aha1 interactions with novobiocin-based Hsp90 C-terminal inhibitors may limit the metastatic potential of tumors.

The 90-kDa heat-shock protein (Hsp90) assists in the proper folding of numerous mutated or overexpressed signal transduction proteins that are involved in cancer. Inhibiting Hsp90 consequently is an attractive strategy for cancer therapy as the concomitant degradation of multiple oncoproteins may lead to effective antineoplastic agents. Here we report a novel C-terminal Hsp90 inhibitor, designated KU675, that exhibits potent antiproliferative and cytotoxic activity along with client protein degradation without induction of the heat-shock response in both androgen-dependent and -independent prostate cancer cell lines. In addition, KU675 demonstrates direct inhibition of Hsp90 complexes as measured by the inhibition of luciferase refolding in prostate cancer cells. In direct binding studies, the internal fluorescence signal of KU675 was used to determine the binding affinity of KU675 to recombinant Hsp90α, Hsp90β, and Hsc70 proteins. The binding affinity (Kd) for Hsp90αwas determined to be 191 μM, whereas the Kdfor Hsp90βwas 726 μM, demonstrating a preference for Hsp90α. Western blot experiments with four different prostate cancer cell lines treated with KU675 supported this selectivity by inducing the degradation of Hsp90α-dependent client proteins. KU675 also displayed binding to Hsc70 with a Kdvalue at 76.3 μM, which was supported in cellular by lower levels of Hsc70-specific client proteins on Western blot analyses. Overall, these findings suggest that KU675 is an Hsp90 C-terminal inhibitor, as well as a dual inhibitor of Hsc70, and may have potential use for the treatment of cancer.

Over the last three decades, entanglement entropy has been obtained for quantum fields propagating in Genus-0 topologies (spheres). For scalar fields propagating in these topologies, it has been shown that the entanglement entropy scales as area. In the last few years, nontrivial topologies are increasingly relevant for different areas. For instance, in describing quantum phases, it has been realized that long-range entangled states are described by topological order. If quantum entanglement can plausibly provide explanation for these, it is then imperative to obtain entanglement entropy in these topologies. In this work, using two different methods, we explicitly show that the entanglement entropy scales as area of the Genus-1 geometry. [ABSTRACT FROM AUTHOR]

AbstractDelta operator modelling of dynamical systems provides a unified framework for identification and control of continuous time systems from discrete time input–output data. This paper proposes applications of neural network for identification and control of dynamical system modelled with delta operator. Delta operator models are recasted into a few realizable neural network structures using the properties of delta operator. The theoretical framework and analytical methods are presented for identification and control of single input single output systems using the numerical robustness properties of delta operator. Simulation examples are presented to demonstrate that the proposed methods work very well.

We show that the variations of the ground state entanglement in linear, higher spatial derivative field theories at zero temperature have signatures of phase transition. Around the critical point, when the dispersion relation changes from linear to nonlinear, there is a fundamental change in the reduced density matrix leading to a change in the scaling of entanglement entropy. We suggest possible explanations involving both kinematical and dynamical effects. We discuss the implication of our work for 2D condensed matter systems, black-hole entropy, and models of quantum gravity. [ABSTRACT FROM AUTHOR]

Acetylation of the SUN protein Mps3 by Eco1 regulates nuclear organization, including chromosome cohesion, telomere tethering, and gene silencing, without affecting Mps3 distribution in the nuclear membrane. It is one of the regulatory pathways known to affect chromosome positioning within the nucleus.

The defining feature of eukaryotic cells is the double lipid bilayer of the nuclear envelope (NE) that serves as a physical barrier separating the genome from the cytosol. Nuclear pore complexes (NPCs) are embedded in the NE to facilitate transport of proteins and other macromolecules into and out of the nucleus. In fungi and early embryos where the NE does not completely breakdown during mitosis, microtubule-organizing centers such as the spindle pole body (SPB) must also be inserted into the NE to facilitate organization of the mitotic spindle. Several recent papers have shed light on the mechanism by which SPB complexes are inserted into the NE. An unexpected link between the SPB and NPCs suggests that assembly of these NE complexes is tightly coordinated. We review the findings of these reports in light of our current knowledge of SPB, NPC and NE structure, assembly and function.

Biofilms of Candida albicans include both yeast cells and hyphae. Prior studies indicated that a zap1Δ/Δ mutant, defective in zinc regulator Zap1, has increased accumulation of yeast cells in biofilms. This altered yeast-hypha balance may arise from internal regulatory alterations or from an effect on the production of diffusible quorum-sensing (QS) molecules. Here, we develop biosensor reporter strains that express yeast-specific YWP1-RFP or hypha-specific HWP1-RFP, along with a constitutive TDH3-GFP normalization standard. Seeding these biosensor strains into biofilms allows a biological activity assay of the surrounding biofilm milieu. A zap1Δ/Δ biofilm induces the yeast-specific YWP1-RFP reporter in a wild-type biosensor strain, as determined by both quantitative reverse transcription-PCR (qRT-PCR) gene expression measurements and confocal microscopy. Remediation of the zap1Δ/Δ zinc uptake defect through zinc transporter gene ZRT2 overexpression reverses induction of the yeast-specific YWP1-RFP reporter. Gas chromatography-mass spectrometry (GC-MS) measurements of known organic QS molecules show that the zap1Δ/Δ mutant accumulates significantly less farnesol than wild-type or complemented strains and that ZRT2 overexpression does not affect farnesol accumulation. Farnesol is a well-characterized inhibitor of hypha formation; hence, a reduction in farnesol levels in zap1Δ/Δ biofilms is unexpected. Our findings argue that a Zap1- and zinc-dependent signal affects the yeast-hypha balance and that it is operative in the low-farnesol environment of the zap1Δ/Δ biofilm. In addition, our results indicate that Zap1 is a positive regulator of farnesol accumulation.

In this article, we explore the kinematics of timelike geodesic congruences in warped five-dimensional bulk spacetimes, with and without thick or thin branes. Beginning with geodesic flows in the Randall-Sundrum anti-de Sitter geometry without and with branes, we find analytical expressions for the expansion scalar and comment on the effects of including thin branes on its evolution. Later, we move on to congruences in more general warped bulk geometries with a cosmological thick brane and a time- dependent extra dimensional scale. Using analytical expressions for the velocity field, we interpret the expansion, shear and rotation (ESR) along the flows, as functions of the extra dimensional coordinate. The evolution of a cross-sectional area orthogonal to the congruence, as seen from a local observer's point of view, is also shown graphically. Finally, the Raychaudhuri and geodesic equations in backgrounds with a thick brane are solved numerically in order to figure out the role of initial conditions (prescribed on the ESR) and spacetime curvature on the evolution of the ESR. [ABSTRACT FROM AUTHOR]

A hybrid computing scheme has been developed in the paper, which uses CFD softwares: Gambit for mesh generation, Fluent for carrying out hydrodynamic analysis, and employs a Genetic Algorithm (GA) for optimisation. It has been utilised to solve optimisation problems related to thermo-fluid field in a fully automated way by using specific system commands. In the developed hybrid computing scheme, the GA and CFD softwares combine each other seamlessly and data transfer takes places without any manual intervention. In this study, the main challenge lies in embedding highly structured commercial softwares, like Fluent and Gambit, inside an indigenously developed hybrid computing scheme. Using the said hybrid computing scheme, two different methodologies have been adopted to optimise the shapes of 2D symmetric nozzle. Corresponding to the optimised shapes of the nozzle, streamline patterns have been developed and variations in pressure loss (PL) factor values have been studied.

ABSTRACTThe opportunistic fungal pathogen Candida albicansis a part of the normal flora but it also causes systemic candidiasis if it reaches the bloodstream. Upon being phagocytized by macrophages, an important component of innate immunity, C. albicansrapidly upregulates a set of arginine biosynthetic genes. Arginine, urea, and CO2induced hyphae in a density-dependent manner in wild-type, cph1/cph1, and rim101/rim101strains but not in efg1/efg1or cph1/cph1 efg1/efg1strains. Arginase (Car1p) converts arginine to urea, which in turn is degraded by urea amidolyase (Dur1,2p) to produce CO2, a signal for hyphal switching. We used a dur1,2/dur1,2mutant (KWN6) and the complemented strain, KWN8 (dur1,2/dur1,2::DUR1,2/DUR1,2) to study germ tube formation. KWN6 could not make germ tubes in the presence of arginine or urea but did in the presence of 5% CO2, which bypasses Dur1,2p. We also tested the effect of arginine on the interaction between the macrophage line RAW 264.7 and several strains of C. albicans. Arginine activated an Efg1p-dependent yeast-to-hypha switch, enabling wild-type C. albicansand KWN8 to escape from macrophages within 6 h, whereas KWN6 was defective in this regard. Additionally, two mutants that cannot synthesize arginine, BWP17 and SN152, were defective in making hyphae inside the macrophages, whereas the corresponding arginine prototrophs, DAY286 and SN87, formed germ tubes and escaped from macrophages. Therefore, metabolism of arginine by C. albicanscontrols hyphal switching and provides an important mechanism for escaping host defense.

The opportunistic fungal pathogen Candida albicans is a part of the normal flora but it also causes systemic candidiasis if it reaches the bloodstream. Upon being phagocytized by macrophages, an important component of innate immunity, C. albicans rapidly upregulates a set of arginine biosynthetic genes. Arginine, urea, and CO2induced hyphae in a density-dependent manner in wild-type, cph1/cph1, and rim101/rim101 strains but not in efg1/efg1 or cph1/cph1 efg1/efg1 strains. Arginase (Car1p) converts arginine to urea, which in turn is degraded by urea amidolyase (Dur1,2p) to produce CO2, a signal for hyphal switching. We used a dur1,2/dur1,2 mutant (KWN6) and the complemented strain, KWN8 (dur1,2/dur1,2::DUR1,2/DUR1,2) to study germ tube formation. KWN6 could not make germ tubes in the presence of arginine or urea but did in the presence of 5% CO2, which bypasses Dur1,2p. We also tested the effect of arginine on the interaction between the macrophage line RAW 264.7 and several strains of C. albicans. Arginine activated an Efg1p-dependent yeast-to-hypha switch, enabling wild-type C. albicans and KWN8 to escape from macrophages within 6 h, whereas KWN6 was defective in this regard. Additionally, two mutants that cannot synthesize arginine, BWP17 and SN152, were defective in making hyphae inside the macrophages, whereas the corresponding arginine prototrophs, DAY286 and SN87, formed germ tubes and escaped from macrophages. Therefore, metabolism of arginine by C. albicans controls hyphal switching and provides an important mechanism for escaping host defense.

In this paper, we study supplier‐firm interactions to explain firms' outsourcing relationships. We show that in an imperfect information setup a firm learns about the quality of its suppliers through repeated interaction. As the firm determines the suppliers' quality with greater precision, it gives a greater proportion of its contracts to these “better” suppliers. We report evidence from African manufacturing firms that is consistent with our hypothesis: both frequency and volume of transactions increase with the length of a firm's relationship with its supplier. These effects are stronger in poor contracting environments.

•Mussel inspired approach was adopted to fabricate catalytic active AgNPs@CeO2nanostructured material.•In-situgrown AgNPs exhibit quasi-spherical shape having average size of 6.50 nm.•The fabricated catalytic nanostructured can efficiently reduce toxic 4-NP and MB dye.

Attempt is made to define the shape of 2-lobe rotor-profile using three arcs. Mathematical model is proposed, and the rotor-profile is successfully parameterized in terms of two independent parameters (base and waist circle radius). Unsteady internal hydrodynamics and heat interaction of the Roots blower are captured using transient finite volume method with an adaptive mesh redistribution technique (moving mesh method) by considering different shapes of rotor-profile. At first, the present numerical scheme is validated with the results available in the literature. Spatial distribution of pressure, velocity, stream function, and temperature throughout the flow domain is extracted at different time instants considering different shapes of the rotor-profile. For better understanding, time variation in area-weighted average velocity magnitude, mass flux, and temperature at the exit port is also evaluated corresponding to each of the rotor-profiles. Transient distribution of pressure, velocity, temperature in the flow domain, leakage at the inlet, backflow at the outlet as well as the time variation in velocity, mass flowrate, and temperature at the exit port is found very sensitive to the shape of the rotor-profile. Attempt is made to establish relation between performance of the Roots blower and shape of the rotor-profile using multiple regression analysis and neurobiological computational approaches (neural network guided by parametric study and neural network tuned by genetic algorithm). Only using the indigenously developed hybrid neurobiological computational scheme with evolutionary algorithm (obtained through perfect amalgam of local search tool: backpropagation algorithm and global search tool: genetic algorithm), the said relation is perfectly captured and blower performance (in terms of discharge mass flux) is perfectly predicted (by knowing the shape of the rotor-profile).

• A dynamic model of infected population to estimate the propagation pattern of COVID -19 pandemics. • Provision of incorporating several influencing factors in proposed model such as inter and intra zone mobilization, detection rate etc. • Different remedial steps are applied as operating procedures to the model in both standalone and hybridized mode. • Flexibility of obtaining probable infected pattern of a particular region or country by proper tuning of the different coefficient of proposed model. • Validation of the model for three geographical locations within India with real world data. Most of the widely populated countries across the globe have been observing vicious spread and detrimental effects of pandemic COVID-19 since its inception on December 19. Therefore to restrict the spreading of pandemic COVID-19, various researches are going on in both medical and administrative sectors. The focus has been given in this research keeping an administrative point of view in mind. In this paper a dynamic model of infected population due to spreading of pandemic COVID-19 considering both intra and inter zone mobilization factors with rate of detection has been proposed. Few factors related to intra zone mobilization; inter zone mobilization and rate of detection are the key points in the proposed model. Various remedial steps are taken into consideration in the form of operating procedures. Further such operating procedures are applied over the model in standalone or hybridized mode and responses are reported in this paper in a case-studies manner. Further zone-wise increase in infected population due to the spreading of pandemic COVID-19 has been studied and reported in this paper. Also the proposed model has been applied over the real world data considering three states of India and the predicted responses are compared with real data and reported with bar chart representation in this paper. [ABSTRACT FROM AUTHOR]

We apply the Dirac-Bergmann algorithm for the analysis of constraints to gauge theories defined on spherically symmetric black hole backgrounds. We find that the constraints for a given theory are modified on such spacetimes through the presence of additional contributions from the horizon. As a concrete example, we consider the Maxwell field on a black hole background, and determine the role of the horizon contributions on the dynamics of the theory. [ABSTRACT FROM AUTHOR]