Designing of 3D Architecture Flower-like Mn-Promoted MgO and Its Application for CO2 Adsorption and CO2-Assisted Aerobic Oxidation of Alkylbenzenes.

Sustainable chemistry research prioritizes reducing atmospheric carbon dioxide, and one logical solution is to develop adsorbents suitable for carbon capture and utilization. In this work, a new family of three-dimensional (3D) flower-like Mn-promoted MgO was synthesized by the coprecipitation method and used as an adsorbent for CO2 capture and a catalyst for CO2 utilization. The scanning electron microscopy (SEM) analysis of the samples shows a 3D architecture composed of thin nanosheets. The X-ray diffraction (XRD) analysis confirms the presence of the MgO with a cubic structure, while X-ray photoelectron spectroscopy (XPS) reveals the existence of Mn particles as a combination of Mn3+ and Mn4+ ions on MgO. N2 adsorption-desorption experiments highlight the beneficial contribution of Mn particles to surface area enhancement and reveal the existence of mesopores. Furthermore, the designed 3D Mn-doped MgO as an adsorbent demonstrates its capability to improve the ability of MgO to adsorb CO2 (from 0.28 mmol/g for pure MgO to 0.74 mmol/g) in ambient conditions and it is regenerable up to 9 cycles with a slight variation after the third cycle. Moreover, Mn-doped MgO shows good catalyst activity for the oxidation of ethylbenzene derivatives to carbonyl compounds in the presence of CO2 and O2. Mn-15/MgO shows excellent catalytic behavior with a conversion of 97.4 and 100% selectivity. Also, it is regenerable with an insignificant decrease in conversion (∼11.63%) after seven cycles, while the selectivity of acetophenone remains stable. The analyses of the recycled sample suggest that the chemical compositions of Mn and Mg influence the catalytic activity of those Mn-promoted MgO materials. The role of CO2 gas in the aerobic oxidation of ethylbenzene to acetophenone has also been proved. Finally, the control experiments and EPR studies reveal that the reaction takes place through the formation of radicals.

Pentosan polysulfate inhibits attachment and infection by SARS-CoV-2 in vitro: insights into structural requirements for binding.

Two years since the outbreak of the novel coronavirus SARS-CoV-2 pandemic, there remain few clinically effective drugs to complement vaccines. One is the anticoagulant, heparin, which in 2004 was found able to inhibit invasion of SARS CoV (CoV-1) and which has been employed during the current pandemic to prevent thromboembolic complications and moderate potentially damaging inflammation. Heparin has also been shown experimentally to inhibit SARS-CoV-2 attachment and infection in susceptible cells. At high therapeutic doses however, heparin increases the risk of bleeding and prolonged use can cause heparin-induced thrombocytopenia, a serious side-effect. One alternative, with structural similarities to heparin is the plant-derived, semi-synthetic polysaccharide, pentosan polysulfate (PPS). PPS is an established drug for the oral treatment of interstitial cystitis, is well-tolerated and exhibits weaker anticoagulant effects than heparin. In an established Vero cell model, PPS and its fractions of varying molecular weights, inhibited invasion by SARS-CoV-2. Intact PPS and its size-defined fractions were characterized by molecular weight distribution and chemical structure using NMR spectroscopy and LC-MS, then employed to explore the structural basis of interactions with SARS-CoV-2 spike protein receptor-binding domain (S1 RBD) and the inhibition of Vero cell invasion. PPS was as effective as unfractionated heparin, but more effective at inhibiting cell infection than low molecular weight heparin (on a weight/volume basis). Isothermal titration calorimetry and viral plaque-forming assays demonstrated size-dependent binding to S1 RBD and inhibition of Vero cell invasion, suggesting the potential application of PPS as a novel inhibitor of SARS-CoV-2 infection.

In situ Generated Ru(0)-HRO@Na-ß From Hydrous Ruthenium Oxide (HRO)/Na-ß: An Energy-Efficient Catalyst for Selective Hydrogenation of Sugars.

A green process for the hydrogenation of sugars to sugar alcohols was designed in aqueous medium using hydrous ruthenium oxide (HRO) as a pre-catalyst supported on Na-ß zeolite. Under optimized reaction conditions, sugars such as xylose, glucose, and mannose converted completely to the corresponding sugar alcohols xylitol, sorbitol, and mannitol with 100% selectivity. The pre-catalyst (HRO) is converted in situ to active Ru(0) species during the reaction under H2, which is responsible for the hydrogenation. The catalyst was recyclable up to five cycles with no loss in activity. The reduction of HRO to the active Ru(0) species is dependent on the reaction temperature and H2 pressure. Ru(0) formation increased and consequently an increased hydrogenation of sugars was observed with an increase in reaction temperature and hydrogen pressure. Further, in situ generation of Ru(0) from HRO was assessed in different solvents such as water, methanol, and tetrahydrofuran; aqueous medium was found to be the most efficient in reducing HRO. This work further demonstrates the use of supported HRO as an efficient pre-catalyst for biomass-based hydrogenation reactions.

Bio-waste chitosan-derived N-doped CNT-supported Ni nanoparticles for selective hydrogenation of nitroarenes.

In this study, a facile method for the synthesis of leach proof and earth-abundant non-noble Ni nanoparticles on N-doped carbon nanotubes is reported. The catalyst was synthesized by an impregnation-carbonization method, wherein a Ni-chitosan complex upon carbonization in a 5% H2/N2 atmosphere at 800 °C yielded Ni-containing N-doped CNTs. Chitosan served as a single source of carbon and nitrogen, and the nanotube growth was facilitated by the in situ formed Ni nanoparticles. The nanocatalyst was thoroughly characterized by several techniques; elemental mapping by SEM and TEM analysis confirmed the uniform distribution of Ni nanoparticles on the surface of N-doped CNTs with an average size in the range of 10-15 nm. The catalyst efficiently reduced a variety of nitroarenes (>99%) into their corresponding amines at a moderate pressure (5 bar) and a comparatively lower temperature (80 °C). Furthermore, the easy recovery of the catalyst using an external magnetic field along with high activity and easy recyclability makes the protocol eco-friendly.

Gram-Scale Synthesis of Flavoring Ketones in One Pot via Alkylation-Decarboxylation on Benzylic Carbon Using a Commercial Solid Acid Catalyst.

The gram-scale synthesis of important flavoring ketones via alkylation of acetoacetic ester on substituted benzylic carbon followed by decarboxylation using a heterogeneous, commercial, solid acid catalyst is reported. The flavoring ketones were synthesized by the alkylation of acetoacetic ester, which proceeds through an SN1-type reaction to generate an alkylated (ß-ketoester) intermediate at the benzylic carbon, which is decarboxylated under the acidic condition. Among the solid acid catalysts used, Amberlyst-15 was found to be the best catalyst under the solvent-free condition. This protocol was successfully employed for the synthesis of various flavoring ketones such as raspberry ketone and ginger ketone with almost complete conversion and 82% isolated yield. The para-donating groups on the benzylic alcohol showed a high rate of reaction. The catalyst was easily recovered and reused 6 times without losing its activity and selectivity. Moreover, this reaction was demonstrated at a 10 g scale, which implicated the potential applicability of the protocol in the industry.

Surfactant-Assisted Selective Oxidation of Aromatic Amines to Nitro Compounds by in Situ-Formed Performic Acid.

Development of novel and greener methods for the selective oxidation of various organic compounds is a challenging task. Herein, a novel protocol for the selective oxidation of aromatic amines to nitroaromatics at room temperature is developed. The oxidation reaction was carried out using a mixture of formic acid and aqueous hydrogen peroxide, which resulted in the in situ formation of performic acid. Further, improvement of selectivity was studied using different surfactants, of which cetyltrimethylammonium bromide (CTAB) gave the highest selectivity (85%) toward nitrobenzene. The role of CTAB in achieving higher selectivity is discussed. Under optimized reaction conditions, various substituted amines were successfully oxidized to corresponding nitro compounds. It is worth mentioning that this is the first report on oxidation of amines to nitro compounds in an aqueous medium with high selectivity.

Role of insulin like growth factor axis in the bleomycin induced lung injury in rats.

BACKGROUND: Alveolar epithelial cell injury has been proposed as a causative factor for the onset and progression of pulmonary fibrosis. However, the role of type II alveolar epithelial cells (AECs) in the epithelial mesenchymal transition (EMT) is controversial. AIMS: The present study performed in rats instilled with bleomycin investigated a) the expressions of the insulin growth factor (IGF-1) and insulin growth factor binding protein 5 (IGFBP-5) and transforming growth factor (TGF-ß1) in the type II AECs, b) the role of type II AECs in EMT and extracellular matrix (ECM) formation and, c) the effect of pioglitazone on all the above parameters. METHODS: Male Wistar rats were divided into three Groups: Group I (saline control), Group II (Bleomycin, given as a single intratracheal instillation, 7U/kg) and Group III (Bleomycin+Pioglitazone (40mg/kg/day orally, starting 7days post bleomycin instilled as in Group II). From lung tissues, the protein expressions of IGF-1, IGFBP-5, TGF-ß1, surfactant protein C (SP-C, as a marker for type II AECs) and α-smooth muscle actin (α-SMA, as a marker for EMT), were determined on day 7 in Groups I and II and on days 14, 21 and 35 in all the three groups. RESULTS: IGFBP-5 and IGF-1 expressions were reduced significantly and TGF-ß1 expression increased significantly in type II AECs in Group II from day 7 till day 35 as compared to Group I. An increase in SP-C and α-SMA expression and their co-localization were seen in the type II AECs undergoing EMT from day 7 till day 35. A concomitant remodeling and laying down of ECM was observed also. In Group III, with pioglitazone, there was a reversal with significant up-regulation in IGFBP-5 and IGF-1 expressions and down-regulation of TGF-ß1 in the type II AECs along with a significant decrease in the solid area fraction, EMT and ECM in the lung tissue. CONCLUSIONS: IGFBP-5, IGF-1 and TGF-ß1 in the type II AECs play a key role in lung injury caused by bleomycin and pioglitazone attenuates the lung injury/fibrosis by restoring IGFBP-5 and IGF-1 and decreasing TGF-ß1 expressions in the type II AECs.

Role of the paraventricular nucleus in the reflex diuresis to pulmonary lymphatic obstruction in rabbits.

The changes in urine flow and renal sympathetic nerve activity (RSNA) due to pulmonary lymphatic obstruction (PLO) were examined in anesthetized, artificially ventilated New Zealand white rabbits. PLO was produced by pressurizing an isolated pouch created in the right external jugular vein at the points of entry of the right lymphatic ducts. During this maneuver, urine flow increased from 8.5 ± 0.3 mL/10 min to 12 ± 0.5 mL/10 min (P < 0.0001) and RSNA increased from 24.0 ± 4 to 40.0 ± 5 µV·s (P < 0.0001). Bilateral lesioning of the paraventricular nucleus (PVN) of the hypothalamus or cervical vagotomy abolished these responses. PLO increased c-fos gene expression in the PVN. The increase in urine flow due to PLO was attenuated by muscimol and abolished by kynurenic acid microinjections into the PVN. The results show that (i) neurons in the PVN are an important relay site in the reflex arc, which is activated by PLO; and (ii) this activation is regulated by glutamatergic and partly by GABAergic input to the PVN.

Population-based characteristics of fatal and hospital admissions for poisoning in Fiji: TRIP Project-11.

This study investigated the incidence and characteristics of poisoning fatalities and hospital admissions among indigenous Fijians and Indians in Viti Levu, Fiji. Individuals with a mechanism of injury classified as poisoning were identified using the Fiji injury surveillance in hospitals system, a population-based registry established for 12 months in Viti Levu, and analysed using population-based denominators. The mean annual rates of fatalities and hospitalisations were 2.3 and 26.0 per 100 000, respectively. Over two-thirds of poisonings occurred among people of Indian ethnicity. Most intentional poisoning admissions occurred among women (58.3%) and in 15-29-year-old individuals (73.8%). Unintentional poisoning admission rates were highest among Indian boys aged 0-14 years. While over 75% of events occurred at home, the substances involved were not systematically identified. The findings indicate the need for a strategy that addresses the differing contexts across age group, gender and ethnicity, and a lead agency responsible for implementing and monitoring its effectiveness.

Attenuation of angiotensin converting enzyme inhibitor induced cough by iron supplementation: role of nitric oxide.

The present study examined whether (1) the cough associated with angiotensin converting enzyme inhibitor therapy is attenuated by oral intake of iron and anti-oxidants, and (2) nitric oxide (NO) has any role in this attenuation. Of the 100 patients under investigation, cough occurred in 28 of them with preponderance in females. All the 28 patients were followed up for six weeks: the first two weeks were the observation period and the remaining four weeks the experimentation period. After the observation period, 11 patients received a single oral dose of ferrous sulphate (200 mg), eight received vitamin E (200 mg, o.d.) and vitamin C (150 mg, o.d.) and nine were given placebo during the experimentation period. Cough scoring, serum NO and malondialdehyde (MDA) levels were determined during both the periods. While there were significant decreases in cough scores, NO and MDA levels between these two periods in the iron group, cough scores and MDA level decreased significantly in the anti-oxidant group. None of these parameters changed in the control group. NO level was found to be increased significantly in patients who developed cough (n = 28) compared with those who did not cough (n = 72). These results suggest that iron supplementation suppresses cough in patients on ACE-I therapy through its effect on NO generation.

Rapidly adapting receptors in acute heart failure and their impact on dyspnea.

Acute heart failure is associated with dyspnea that is usually defined as difficulty in breathing that is accompanied by an element of distress. It is commonly associated with an increase in the rate of ventilation, wheezing, an increase in airway secretions and cough. This review examines the reflexes which generate these responses with particular reference to the role of rapidly adapting receptors (RAR) in the airways. The essential feature of acute heart failure is an increase in pulmonary extravascular fluid volume. Small acute increases in extravascular fluid volume in the airways activate the RAR. With larger increases both the RAR and the C-fiber receptors in the airways and the alveoli are activated. Activation of RAR causes a reflex increase in respiratory rate, tracheal tone and mucus secretion from the airways. It is suggested that the RAR play a significant role in monitoring changes in the extravascular fluid volume of the airways and mediate the respiratory reflexes associated with acute heart failure.

Left ventricular dysfunction and extravascular fluid in the lung: physiological basis for symptoms.

The essential feature of left ventricular dysfunction is an increase in left atrial pressure and pulmonary venous congestion leading to a fluid flux across the pulmonary microvasculature. Small acute increases (< 10 mmHg) in left atrial pressure enhance the extravascular fluid volume in the airways and activate the rapidly adapting receptors (RAR). With larger increases in left atrial pressure (approximately 25 mmHg) both the RAR and the C-fiber receptors in the airways and the alveoli are activated. Activation of RAR causes a reflex increase in respiratory rate, tracheal tone and mucus secretion from the airways. It appears that small increases in extravascular fluid volume of the airways also cause a reflex diuresis which is mediated by activation of neuronal nitric oxide synthase in the renal medulla. In contrast, when left atrial pressure is elevated chronically, further small increments in extravascular fluid volume of the airways no longer stimulate the RAR. The reflex diuresis is also not evident under these circumstances. However, the RAR continue to be activated by increments in left atrial pressure in excess of 25 mmHg. It is suggested that the RAR of the airways play a significant role in monitoring changes in the extravascular fluid volume of the airways and mediate the reflexes which are associated with the symptomatology of acute left ventricular dysfunction.

The rapidly adapting receptors in mammalian airways and their responses to changes in extravascular fluid volume.

In this short review, we shall focus on some recent findings on the physiological stimulus for the rapidly adapting receptors (RAR) of the airways. They are readily activated by a sustained inflation of the lungs and they are usually identified by their rapid adaptation to this stimulus. They are also activated by both tactile stimuli and irritant gases applied to the epithelium of the airways. The investigations reviewed here suggest that these receptors are activated by changes in extravascular fluid volume. The principal factors governing fluid flux from the microcirculation are identified in the Starling equation. These are the hydrostatic pressure, plasma oncotic pressure and capillary permeability. Findings from recent studies suggest that all these factors increase the activity of RAR. In addition, these receptors are also activated by obstruction of lymph drainage from the lung. Evidence is presented to show that manipulation of Starling forces also increases the extravascular fluid volume of the airways in areas where the RAR are located. On the basis of these findings, it is suggested that, along with mechanosensitivity to stimuli such as stretch, inflation and deflation, another physiological stimulus to the RAR is a change in extravascular fluid volume in the regions of the airways where these receptors are located.