Magnetite Metal-Organic Frameworks: Applications in Environmental Remediation of Heavy Metals, Organic Contaminants, and Other Pollutants.

Due to the increasing environmental pollution caused by human activities, environmental remediation has become an important subject for humans and environmental safety. The quest for beneficial pathways to remove organic and inorganic contaminants has been the theme of considerable investigations in the past decade. The easy and quick separation made magnetic solid-phase extraction (MSPE) a popular method for the removal of different pollutants from the environment. Metal-organic frameworks (MOFs) are a class of porous materials best known for their ultrahigh porosity. Moreover, these materials can be easily modified with useful ligands and form various composites with varying characteristics, thus rendering them an ideal candidate as adsorbing agents for MSPE. Herein, research on MSPE, encompassing MOFs as sorbents and Fe3O4 as a magnetic component, is surveyed for environmental applications. Initially, assorted pollutants and their threats to human and environmental safety are introduced with a brief introduction to MOFs and MSPE. Subsequently, the deployment of magnetic MOFs (MMOFs) as sorbents for the removal of various organic and inorganic pollutants from the environment is deliberated, encompassing the outlooks and perspectives of this field.

Structural alterations in fast-spiking GABAergic interneurons in a model of posttraumatic neocortical epileptogenesis.

Electrophysiological experiments in the partial cortical isolation ("undercut" or "UC") model of injury-induced neocortical epileptogenesis have shown alterations in GABAergic synaptic transmission attributable to abnormalities in presynaptic terminals. To determine whether the decreased inhibition was associated with structural abnormalities in GABAergic interneurons, we used immunocytochemical techniques, confocal microscopy and EM in UC and control sensorimotor rat cortex to analyze structural alterations in fast-spiking parvalbumin-containing interneurons and pyramidal (Pyr) cells of layer V. Principle findings were: 1) there were no decreases in counts of parvalbumin (PV)- or GABA-immunoreactive interneurons in UC cortex, however there were significant reductions in expression of VGAT and GAD-65 and -67 in halos of GABAergic terminals around Pyr somata in layer V. 2) Consistent with previous results, somatic size and density of Pyr cells was decreased in infragranular layers of UC cortex. 3) Dendrites of biocytin-filled FS interneurons were significantly decreased in volume. 4) There were decreases in the size and VGAT content of GABAergic boutons in axons of biocytin-filled FS cells in the UC, together with a decrease in colocalization with postsynaptic gephyrin, suggesting a reduction in GABAergic synapses. Quantitative EM of layer V Pyr somata confirmed the reduction in inhibitory synapses. 5) There were marked and lasting reductions in brain derived neurotrophic factor (BDNF)-IR and -mRNA in Pyr cells and decreased TrkB-IR on PV cells in UC cortex. 6) Results lead to the hypothesis that reduction in trophic support by BDNF derived from Pyr cells may contribute to the regressive changes in axonal terminals and dendrites of FS cells in the UC cortex and decreased GABAergic inhibition. SIGNIFICANCE: Injury to cortical structures is a major cause of epilepsy, accounting for about 20% of cases in the general population, with an incidence as high as ~50% among brain-injured personnel in wartime. Loss of GABAergic inhibitory interneurons is a significant pathophysiological factor associated with epileptogenesis following brain trauma and other etiologies. Results of these experiments show that the largest population of cortical interneurons, the parvalbumin-containing fast-spiking (FS) interneurons, are preserved in the partial neocortical isolation model of partial epilepsy. However, axonal terminals of these cells are structurally abnormal, have decreased content of GABA synthetic enzymes and vesicular GABA transporter and make fewer synapses onto pyramidal neurons. These structural abnormalities underlie defects in GABAergic neurotransmission that are a key pathophysiological factor in epileptogenesis found in electrophysiological experiments. BDNF, and its TrkB receptor, key factors for maintenance of interneurons and pyramidal neurons, are decreased in the injured cortex. Results suggest that supplying BDNF to the injured epileptogenic brain may reverse the structural and functional abnormalities in the parvalbumin FS interneurons and provide an antiepileptogenic therapy.

Green stabilization of silver nanoparticles over the surface of biocompatible Fe3O4@CMC for bactericidal applications.

The emergence of antimicrobial resistance in bacteria, especially in agents associated with urinary tract infections (UTIs), has initiated an exciting effort to develop biocompatible nanoparticles to confront their threat. Designing simple, cheap, biocompatible, and efficient nanomaterials as bactericidal agents seems to be a judicious response to this problem. Here, a solvothermal method was hired for the one-pot preparation of the cellulose gum (carboxymethyl cellulose, CMC) magnetic composite to prepare a cost-effective, efficient, and biocompatible support for the plant-based stabilization of the silver NPs. The green stabilization of the Ag NPs is performed using Euphorbia plant extract with high efficiency. Various characterization methods, including FT-IR, XRD, SEM, EDS, TEM, and VSM were used to study the composition and properties of Fe3O4@CMC/AgNPs. The composite shows well integrity and monodispersity with a mean diameter of <300 nm, indicating its potential for bio-related application. The CMC functionalities of the proposed material facilitated the stabilization of the Ag NPs, resulting in their monodispersity and enhanced performance. The manufactured composite was used as an antibacterial agent for the removal of UTIs agents, collected from 200 hospitalized patients with acute coronary syndrome, which showed promising results. This study showed that the concentration of the Ag NPs has a direct relationship with the antibacterial properties of the composite.

Bactericidal behavior of silver nanoparticle decorated nano-sized magnetic hydroxyapatite.

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common cause of acute bacterial arthritis. Due to the increase in antibiotic resistance in these bacteria, the discovery of new antibacterial agents has become one of the hot topics in the scientific community. Here, we prepared a nano-sized porous biocompatible magnetic hydroxyapatite through a solvothermal method. Then, we adopted a post-synthesis modification strategy to modify its surface for the stabilization of Ag NPs through a green reduction by the euphorbia plant extract. Moreover, the results show that the prepared composite perfectly prevents the aggregation of Ag NPs. This composite was used as a bactericidal and antibiofilm agent against MRSA bacteria in an in vitro environment, which showed excellent results. Also, the cell viability assay indicates that the prepared composite has low cytotoxicity, making it a perfect antibacterial agent for in vivo experiments.

Stabilization of Pd NPs over the surface of ß-cyclodextrin incorporated UiO-66-NH2 for the C-C coupling reaction.

Here, we prepared UiO-66-NH2 and employed a post-synthesis modification method for its functionalization with a ß-cyclodextrin (ß-CD) organic compound. The resulting composite was employed as a support for the heterogenization of the Pd NPs. Various techniques, including FT-IR, XRD, SEM, TEM, EDS, and elemental mapping, were used to characterize UiO-66-NH2@ß-CD/PdNPs, indicating its successful preparation. Three C-C coupling reactions, including the Suzuki, Heck, and Sonogashira coupling reactions, were promoted using the produced catalyst. As a result of the PSM, the proposed catalyst displays improved catalytic performance. In addition, the suggested catalyst was highly recyclable up to 6 times.

Gold nanoparticle decorated post-synthesis modified UiO-66-NH2 for A3-coupling preparation of propargyl amines.

In this report, the novel UiO­66­NH2 based-MOF(Zr) catalytic system which further modified with nitrogen-rich organic ligand (5-aminotetrazole) using post synthetic modification (PSM) approach has been prepared here as an efficient catalyst to promote the A3-coupling preparation of propargyl amines in green aquatic media. This newly highly efficient catalyst was synthesized upon Zr-based MOF (UiO­66­NH2) which successfully functionalized with 2,4,6­trichloro­1,3,5­triazine (TCT) and 5­aminotetrazole, following through stabilization of gold metal (Au) nanopartilces. The addition of N-rich organic ligand through post-synthesis modification which can be assisted to stabilize the bister and stable gold nanoparticles caused to unique structure of the final composite in favor of the progress of the A3 coupling reaction. Also several strategies comprising XRD, FT-IR, SEM, BET, TEM, TGA, ICP, EDS and elemental mapping analyzes, were used to indicate the successful preparation of the UiO-66-NH2@ Cyanuric Chloride@ 5-amino tetrazole/Au-NPs. The results of productivity catalyst are accomplished in good to excellent yields for all sort of reactions under mild conditions which is a proof of superior activity heterogeneous catalyst containing Au-nanoparticles. In addition, the suggested catalyst represented excellent reusability with no remarkable loss in activity up 9 sequential runs.

Prediction of delayed cerebral ischemia after cerebral aneurysm rupture using explainable machine learning approach.

BACKGROUND: Aneurysmal subarachnoid hemorrhage results in significant mortality and disability, which is worsened by the development of delayed cerebral ischemia. Tests to identify patients with delayed cerebral ischemia prospectively are of high interest. OBJECTIVE: We created a machine learning system based on clinical variables to predict delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage patients. We also determined which variables have the most impact on delayed cerebral ischemia prediction using SHapley Additive exPlanations method. METHODS: 500 aneurysmal subarachnoid hemorrhage patients were identified and 369 met inclusion criteria: 70 patients developed delayed cerebral ischemia (delayed cerebral ischemia+) and 299 did not (delayed cerebral ischemia-). The algorithm was trained based upon age, sex, hypertension (HTN), diabetes, hyperlipidemia, congestive heart failure, coronary artery disease, smoking history, family history of aneurysm, Fisher Grade, Hunt and Hess score, and external ventricular drain placement. Random Forest was selected for this project, and prediction outcome of the algorithm was delayed cerebral ischemia+. SHapley Additive exPlanations was used to visualize each feature's contribution to the model prediction. RESULTS: The Random Forest machine learning algorithm predicted delayed cerebral ischemia: accuracy 80.65% (95% CI: 72.62-88.68), area under the curve 0.780 (95% CI: 0.696-0.864), sensitivity 12.5% (95% CI: -3.7 to 28.7), specificity 94.81% (95% CI: 89.85-99.77), PPV 33.3% (95% CI: -4.39 to 71.05), and NPV 84.1% (95% CI: 76.38-91.82). SHapley Additive exPlanations value demonstrated Age, external ventricular drain placement, Fisher Grade, and Hunt and Hess score, and HTN had the highest predictive values for delayed cerebral ischemia. Lower age, absence of hypertension, higher Hunt and Hess score, higher Fisher Grade, and external ventricular drain placement increased risk of delayed cerebral ischemia. CONCLUSION: Machine learning models based upon clinical variables predict delayed cerebral ischemia with high specificity and good accuracy.

Gold nanoparticle decorated dithiocarbamate modified natural boehmite as a catalyst for the synthesis of biologically essential propargylamines.

Here, we prepare an Au NP decorated dithiocarbamate functionalized boehmite (γ-AlO(OH)@C-NHCS2H·AuNPs). This stepwise synthetic method gives an efficient, cost-effective, and green heterogenous Au-based nanocatalyst for the A3-coupling preparation of the biologically essential propargylamines. Different characterization methods, including FT-IR, XRD, SEM, TEM, EDX spectra, and elemental SEM-mapping, were employed to investigate the structure of the manufactured γ-AlO(OH)@C-NHCS2H·AuNPs. Then we used the prepared composite as a heterogeneous gold-based nanocatalyst for the one-pot A3-coupling preparation of propargyl amines by reacting a variety of aldehydes, amines, and phenylacetylene which exhibited promising results.

Mesoporous Ionically Tagged Cross-Linked Poly(vinyl imidazole)s as Novel and Reusable Catalysts for the Preparation of N-Heterocycle Spiropyrans.

Herein, two novel mesoporous cross-linked poly(vinyl imidazole)s with sulfonic acid tags, [PVI-SO3H]Cl (1) and [PVI-SO3H]FeCl4 (2), were prepared and characterized by a variety of techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, elemental mapping, energy dispersive X-ray analysis, transmission electron microscopy, thermal gravimetry, derivative thermal gravimetry, and N2 adsorption-desorption isotherms (Brunauer-Emmett-Teller). In addition, magnetic properties of poly(vinyl imidazole) sulfonic acid iron(IV) chloride [PVI-SO3H]FeCl4 (2) as an ionically tagged magnetic polymer were investigated using a vibrating sample magnetometer. The presented polymers, [PVI-SO3H]Cl (1) and [PVI-SO3H]FeCl4 (2), were successfully applied as reusable and efficient catalysts for the preparation of N-heterocycle spiropyrans. The described catalysts were recycled and reused with a marginal decrease in their catalytic activities. The desired products were prepared under mild and green conditions. The structures of the obtained products were confirmed by various analysis techniques.

Connective tissue growth factor is induced in bleomycin-induced skin scleroderma.

The origin of fibrotic cells within connective tissue is unclear. For example, the extent to which microvascular pericytes contribute to the number of myofibroblasts present in dermal fibrosis in uncertain. Connective tissue growth factor (CTGF/CCN2) is a marker and mediator of fibrosis. In this report, we use an antibody recognizing CCN2 to assess the cell types in mouse dermis which express CCN2 in the bleomycin model of skin scleroderma. Control (PBS injected) and fibrotic (bleomycin-injected) dermis was examined for CCN2, alpha-smooth muscle actin (alpha-SMA) (to detect myofibroblasts), and NG2 (to detect pericytes) expression. Consistent with previously published data, CCN2 expression was largely absent in the dermis of control mice. However, upon exposure to bleomycin, CCN2 was observed in the dermis. Cells that expressed CCN2 were alpha-SMA-expressing myofibroblasts. Approximately 85% of myofibroblasts were NG2-positive, CCN2-expressing pericytes, indicating that pericytes significantly contributed to the presence of myofibroblasts in sclerotic dermis. Thus CCN2 is induced in fibrotic skin, correlating with the induction of myofibroblast induction. Moreover, CCN2-expressing pericytes significantly contribute to the appearance of myofibroblasts in bleomycin-induced skin scleroderma.

Fiber-types of sarcomeric proteins expressed in cultured myogenic cells are modulated by the dose of myogenin activity.

The myogenic basic helix-loop-helix regulatory factors (MRFs) maintain commitment of proliferating cells to the skeletal myogenic lineage, and contribute to activation of transcription of muscle-specific genes in myocytes and muscle fibers. A clear role for any or all of the MRFs in muscle fiber-type determination, however, has not emerged from expression or genetic studies. During fetal, neonatal and adult life, diversification of muscle fiber types, and the dynamics of slow or fast fiber type adaptation and growth, are controlled by exogenous factors, including innervation, work load, and hormonal signaling. In contrast, stereotypical development of muscle fibers preferentially expressing slow or fast isoforms of sarcomeric proteins in the embryo occurs in the absence of these factors, and appears to be mediated both by input from the surrounding interstitial milieu, as well by cell autonomous mechanisms. We report here that diversification of myogenic cells in culture towards the expression of fast or slow skeletal muscle fiber types can be determined by the activity and dose of at least one MRF, myogenin. The dose of myogenin is modulated by two parameters: the phosphorylation state of the transcriptional activation domains, and the level of expression. Low doses of myogenin promoted a fast phenotype, whereas higher doses promoted a slow phenotype, and further studies suggested that diversification is mediated by both transcriptional and post-transcriptional mechanisms. The potential for dose or numeration signaling by basic helix-loop-helix regulators has been revealed by studies in Drosophila melanogaster, while the present results support the notion that this mechanism may be more commonly employed to generate subdiversity among developing cell types.

Patterns of processing bias for emotional information across clinical disorders: a comparison of attention, memory, and prospective cognition in children and adolescents with depression, generalized anxiety, and posttraumatic stress disorder.

This study investigated theoretical claims that different emotional disorders are associated with different patterns of cognitive bias, both in terms of the cognitive processes involved and the stimulus content that is preferentially processed. These claims were tested by comparing clinically anxious (generalized anxiety disorder [GAD], posttraumatic stress disorder [PTSD]) and clinically depressed children and adolescents on a range of cognitive tasks measuring attention, memory, and prospective cognition, with both threat-related and depressogenic stimulus materials. The results did reveal some relative specificity of processing in that the anxious participants exhibited a greater selective attentional bias for threat relative to depressogenic material with no such difference being apparent in the depressed sample. However, this bias was only clear-cut on a dot-probe measure of attentional processing and not on a modified Stroop measure, and indeed threat-related bias on the 2 tasks was uncorrelated. On the prospective cognition task, anxious participants exhibited an other-referent bias in their risk estimations regarding future negative events that was absent in the depressed sample. No specificity effects were evident on the memory task. The results are discussed in terms of the strengths and weaknesses of carrying out direct comparisons across groups and tasks versus drawing conclusions from overall patterns across multiple studies.