Electrostatic aggregation and formation of core-shell suprastructures in binary mixtures of charged metal nanoparticles

Electrostatic aggregation of oppositely charged silver and gold nanoparticles leads to the formation of core-shell clusters in which the shell is formed by the nanoparticles, which are in excess. Arguments based on Debye screening of interactions between like-charged particles help explain why these clusters are stable despite possessing net electric charge. The core-shell aggregates exhibit unusual optical properties with the resonance absorption of the shell particles enhanced by the particles in the core and that of the core suppressed by the shell. Experimental UV-vis absorption spectra are faithfully reproduced by Mie theory. The modeling allows for estimation of the numbers of particles forming the shell and of the shell's effective thickness. These theoretical predictions are substantiated by experiments using nanoparticles covered with different combinations of charged groups and performed at different values of pH.     

Graph grammar‐driven parallel partial differential equation solver

The paper presents an extension of the composite programmable graph grammar (CP‐graph grammar) suitable for modeling the parallel direct solver algorithm utilized by the hp finite element method (hp‐FEM). In the proposed graph grammar model, the computational mesh is represented by a CP‐graph. The presented graph grammar models the solver algorithm by a set of graph grammar productions. The graph grammar model makes it possible to examine the concurrency of the algorithm by analyzing the interdependence between the atomic tasks, tasks and super‐tasks. The atomic tasks correspond to the graph grammar productions, representing basic undividable parts of the algorithms. The level of atomic tasks models the concurrency for the shared memory architectures. On the other hand, the tasks correspond to the groups of atomic tasks with predefined inter‐task communication channels. They constitute the grain for the decomposition of the parallel algorithm for the distributed memory architecture. Finally, the super‐tasks correspond to a group of tasks resulting from the execution of load balancing algorithm. The solver algorithm is tested on distributed memory linux cluster for up to 192 processors. Copyright © 2009 John Wiley & Sons, Ltd.     

Foliar Application of Cerium Oxide-Salicylic Acid Nanoparticles (CeO2:SA Nanoparticles) Influences the Growth and Physiological Responses of Portulaca oleracea L. under Salinity

In the present study, the effects of foliar application of salicylic acid (100 μM), cerium oxide (50 mg L⁻¹), and cerium oxide:salicylic acid nanoparticles (CeO₂: SA-nanoparticles, 50 mg L⁻¹ + 100 μM) on the growth and physiological responses of purslane (Portulaca oleracea L.) were examined in non-saline and saline conditions (50 and 100 mM NaCl salinity). Foliar applications mitigated salinity-induced adverse effects, and the highest plant height and N, P, Mg, and Mn content were recorded in the variant with non-saline × foliar use of CeO₂: SA-nanoparticles. The highest values of fresh and dry weight were noted in the treatment with no-salinity × foliar use of CeO₂:SA-nanoparticles. The highest number of sub-branches was observed in the foliar treatments with CeO₂-nanoparticles and CeO₂:SA-nanoparticles without salinity stress, while the lowest number was noted in the 100 mM NaCl treatment. Moreover, the foliar application of CeO₂:SA-nanoparticles and cerium-oxide nanoparticles improved the total soluble solid content, K, Fe, Zn, Ca, chlorophyll a, and oil yield in the plants. The salinity of 0 and 50 mM increased the K content, 1000-seed weight, total soluble solid content, and chlorophyll b content. The use of 100 mM NaCl with no-foliar spray increased the malondialdehyde, Na, and H₂O₂ content and the Na⁺/K⁺ ratio. No-salinity and 50 mM NaCl × CeO₂: SA-nanoparticle interactions improved the anthocyanin content in plants. The phenolic content was influenced by NaCl₁₀₀ and the foliar use of CeO₂:SA-nanoparticles. The study revealed that the foliar treatment with CeO₂:SA-nanoparticles alleviated the side effects of salinity by improving the physiological responses and growth-related traits of purslane plants.     

The Cooperative Anti-Neoplastic Activity of Polyphenolic Phytochemicals on Human T-Cell Acute Lymphoblastic Leukemia Cell Line MOLT-4 In Vitro

Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecting pediatric patients. ALL treatment regimens with cytostatics manifest substantial toxicity and have reached the maximum of well-tolerated doses. One potential approach for improving treatment efficiency could be supplementation of the current regimen with naturally occurring phytochemicals with anti-cancer properties. Nutraceuticals such as quercetin, curcumin, resveratrol, and genistein have been studied in anti-cancer therapy, but their application is limited by their low bioavailability. However, their cooperative activity could potentially increase their efficiency at low, bioavailable doses. We studied their cooperative effect on the viability of a human ALL MOLT-4 cell line in vitro at the concentration considered to be in the bioavailable range in vivo. To analyze their potential side effect on the viability of non-tumor cells, we evaluated their toxicity on a normal human foreskin fibroblast cell line (BJ). In both cell lines, we also measured specific indicators of cell death, changes in cell membrane permeability (CMP), and mitochondrial membrane potential (MMP). Even at a low bioavailable concentration, genistein and curcumin decreased MOLT-4 viability, and their combination had a significant interactive effect. While resveratrol and quercetin did not affect MOLT-4 viability, together they enhanced the effect of the genistein/curcumin mix, significantly inhibiting MOLT-4 population growth in vitro. Moreover, the analyzed phytochemicals and their combinations did not affect the BJ cell line. In both cell lines, they induced a decrease in MMP and correlating CMP changes, but in non-tumor cells, both metabolic activity and cell membrane continuity were restored in time. (4) Conclusions: The results indicate that the interactive activity of analyzed phytochemicals can induce an anti-cancer effect on ALL cells without a significant effect on non-tumor cells. It implies that the application of the combinations of phytochemicals an anti-cancer treatment supplement could be worth further investigation regardless of their low bioavailability.     

Molecular Level Characterisation of the Surface of Carbohydrate-Functionalised Mesoporous silica Nanoparticles (MSN) as a Potential Targeted Drug Delivery System via High Resolution Magic Angle Spinning (HR-MAS) NMR Spectroscopy

Atomistic level characterisation of external surface species of mesoporous silica nanoparticles (MSN) poses a significant analytical challenge due to the inherently low content of grafted ligands. This study proposes the use of HR-MAS NMR spectroscopy for a molecular level characterisation of the external surface of carbohydrate-functionalised nanoparticles. MSN differing in size (32 nm, 106 nm, 220 nm) were synthesised using the sol-gel method. The synthesised materials displayed narrow particle size distribution (based on DLS and TEM results) and a hexagonal arrangement of the pores with a diameter of ca. 3 nm as investigated with PXRD and N₂ physisorption. The surface of the obtained nanoparticles was functionalised with galactose and lactose using reductive amination as confirmed by FTIR and NMR techniques. The functionalisation of the particles surface did not alter the pore architecture, structure or morphology of the materials as confirmed with TEM imaging. HR-MAS NMR spectroscopy was used for the first time to investigate the structure of the functionalised MSN suspended in D₂O. Furthermore, lactose was successfully attached to the silica without breaking the glycosidic bond. The results demonstrate that HR-MAS NMR can provide detailed structural information on the organic functionalities attached at the external surface of MSN within short experimental times.     

Tracking the Molecular Scenarios for Tumorigenic Remodeling of Extracellular Matrix Based on Gene Expression Profiling in Equine Skin Neoplasia Models

An important component of tissues is the extracellular matrix (ECM), which not only forms a tissue scaffold, but also provides the environment for numerous biochemical reactions. Its composition is strictly regulated, and any irregularities can result in the development of many diseases, including cancer. Sarcoid is the most common skin cancer in equids. Its formation results from the presence of the genetic material of the bovine papillomavirus (BPV). In addition, it is assumed that sarcoid-dependent oncogenic transformation arises from a disturbed wound healing process, which may be due to the incorrect functioning of the ECM. Moreover, sarcoid is characterized by a failure to metastasize. Therefore, in this study we decided to investigate the differences in the expression profiles of genes related not only to ECM remodeling, but also to the cell adhesion pathway, in order to estimate the influence of disturbances within the ECM on the sarcoid formation process. Furthermore, we conducted comparative research not only between equine sarcoid tissue bioptates and healthy skin-derived explants, but also between dermal fibroblast cell lines transfected and non-transfected with a construct encoding the E4 protein of the BP virus, in order to determine its effect on ECM disorders. The obtained results strongly support the hypothesis that ECM-related genes are correlated with sarcoid formation. The deregulated expression of selected genes was shown in both equine sarcoid tissue bioptates and adult cutaneous fibroblast cell (ACFC) lines neoplastically transformed by nucleofection with gene constructs encoding BPV1-E1^E4 protein. The identified genes (CD99, ITGB1, JAM3 and CADM1) were up- or down-regulated, which pinpointed the phenotypic differences from the backgrounds noticed for adequate expression profiles in other cancerous or noncancerous tumors as reported in the available literature data. Unravelling the molecular pathways of ECM remodeling and cell adhesion in the in vivo and ex vivo models of epidermal/dermal sarcoid-related cancerogenesis might provide powerful tools for further investigations of genetic and epigenetic biomarkers for both silencing and re-initiating the processes of sarcoid-dependent neoplasia. Recognizing those biomarkers might insightfully explain the relatively high capacity of sarcoid-descended cancerous cell derivatives to epigenomically reprogram their nonmalignant neoplastic status in domestic horse cloned embryos produced by somatic cell nuclear transfer (SCNT).     

The Role of Kisspeptin in the Pathogenesis of Pregnancy Complications: A Narrative Review

Kisspeptins are the family of neuropeptide products of the KISS-1 gene that exert the biological action by binding with the G-protein coupled receptor 54 (GPR54), also known as the KISS-1 receptor. The kisspeptin level dramatically increases during pregnancy, and the placenta is supposed to be its primary source. The role of kisspeptin has already been widely studied in hypogonadotropic hypogonadism, fertility, puberty disorders, and insulin resistance-related conditions, including type 2 diabetes mellitus, polycystic ovary syndrome, and obesity. Gestational diabetes mellitus (GDM), preeclampsia (PE), preterm birth, fetal growth restriction (FGR), or spontaneous abortion affected 2 to 20% of pregnancies worldwide. Their occurrence is associated with numerous short and long-term consequences for mothers and newborns; hence, novel, non-invasive predictors of their development are intensively investigated. The study aims to present a comprehensive review emphasizing the role of kisspeptin in the most common pregnancy-related disorders and neonatal outcomes. The decreased level of kisspeptin is observed in women with GDM, FGR, and a high risk of spontaneous abortion. Nevertheless, there are still many inconsistencies in kisspeptin concentration in pregnancies with preterm birth or PE. Further research is needed to determine the usefulness of kisspeptin as an early marker of gestational and neonatal complications.     

Catalase Inhibition by Aminoalkanol Derivatives with Potential Anti-Cancer Activity—In Vitro and In Silico Studies Using Capillary Electrophoresis Method

In this work, the investigation of type and inhibitory strength of catalase by two pairs of aminoalkanol derivatives (1,7 diEthyl- and 1,7-diMethyl-8,9-diphenyl-4-azatricyclo (5.2.1.02.6) dec-8-ene- 3,5,10-trione) has been presented. The obtained results allowed for the determination of all kinetic parameters (Km, Vmax, slope angles of Lineweaver–Burk plots, Ki and IC₅₀) on the basis of which it was shown that all four aminoalkanol derivatives are competitive inhibitors of catalase. However, the strength of action of each of them depends on the type of substituents present in the main structure of the molecule. Subtle differences in the potency of individual derivatives were possible to detect thanks to the developed, sensitive method of capillary electrophoresis, which allowed simultaneous monitoring of the mutual changes in the concentrations of substrates and products of the reaction catalyzed by the enzyme. Detailed values of kinetic parameters showed that all derivatives are weak inhibitors of catalase, which in this case is a big advantage because each inhibition of catalase activity is associated with a greater amount of accumulated, harmful reactive oxygen species. The results of docking studies also show the convergence of the binding energies values of individual inhibitors with all kinetic parameters of the investigated catalase inhibition and thus additionally confirm the weak inhibitory strength of all four aminoalkanol derivatives.     

The Relationship between COVID-19 and Hypothalamic–Pituitary–Adrenal Axis: A Large Spectrum from Glucocorticoid Insufficiency to Excess—The CAPISCO International Expert Panel

Coronavirus disease 2019 (COVID-19) is a highly heterogeneous disease regarding severity, vulnerability to infection due to comorbidities, and treatment approaches. The hypothalamic–pituitary–adrenal (HPA) axis has been identified as one of the most critical endocrine targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that might significantly impact outcomes after infection. Herein we review the rationale for glucocorticoid use in the setting of COVID-19 and emphasize the need to have a low index of suspicion for glucocorticoid-induced adrenal insufficiency, adjusting for the glucocorticoid formulation used, dose, treatment duration, and underlying health problems. We also address several additional mechanisms that may cause HPA axis dysfunction, including critical illness-related corticosteroid insufficiency, the direct cytopathic impacts of SARS-CoV-2 infection on the adrenals, pituitary, and hypothalamus, immune-mediated inflammations, small vessel vasculitis, microthrombotic events, the resistance of cortisol receptors, and impaired post-receptor signaling, as well as the dissociation of ACTH and cortisol regulation. We also discuss the increased risk of infection and more severe illness in COVID-19 patients with pre-existing disorders of the HPA axis, from insufficiency to excess. These insights into the complex regulation of the HPA axis reveal how well the body performs in its adaptive survival mechanism during a severe infection, such as SARS-CoV-2, and how many parameters might disbalance the outcomes of this adaptation.     

Biocidal Activity of Tannic Acid-Prepared Silver Nanoparticles towards Pathogens Isolated from Patients with Exacerbations of Chronic Rhinosinusitis

The microbiome’s significance in chronic rhinosinusitis (CRS) is unclear. Antimicrobials are recommended in acute exacerbations of the disease (AECRS). Increasing rates of antibiotic resistance have stimulated research on alternative therapeutic options, including silver nanoparticles (AgNPs). However, there are concerns regarding the safety of silver administration. The aim of this study was to assess the biological activity of tannic acid-prepared AgNPs (TA-AgNPs) towards sinonasal pathogens and nasal epithelial cells (HNEpC). The minimal inhibitory concentration (MIC) for pathogens isolated from patients with AECRS was approximated using the well diffusion method. The cytotoxicity of TA-AgNPswas evaluated using an MTT assay and trypan blue exclusion. A total of 48 clinical isolates and 4 reference strains were included in the study (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Klebsiellaoxytoca, Acinetobacter baumannii, Serratia marcescens, Enterobacter cloacae). The results of the studies revealed that the MIC values differed between isolates, even within the same species. All the isolates were sensitive to TA-AgNPs in concentrations non-toxic to human cells during 24 h exposition. However, 48 h exposure to TA-AgNPs increased toxicity to HNEpC, narrowing their therapeutic window and enabling 19% of pathogens to resist the TA-AgNPs’ biocidal action. It was concluded that TA-AgNPs are non-toxic for the investigated eukaryotic cells after short-term exposure and effective against most pathogens isolated from patients with AECRS, but sensitivity testing may be necessary before application.