PHENOLIC COMPOUNDS FROM CALLISTEMON CITRINUS LEAVES AND STEMS

In the search for bioactive constituents from Vietnamese plants,  the leaves and stems of Callistemon citrinus (Curtis) Skeels were selected for chemical investigation. Phytochemical analysis of plant led to the isolation of eight phenolic compounds including two flavonoids (eucalyptine (1) and 8-demethyleucalyptine (2)), two alcohols (blumenol A (3), n-tetratriacontanol (4)), three benzoic acid derivatives (acid gallic (5), methyl gallate (6) protocatechuic acid (7)), one sterol (b-sitosterol (8)), and along with one sesquiterpene (2,6,10-bisabolatriene (9)). The structures of the natural compounds were determined by spectroscopic evidences including 1D- and 2D-NMR and ESI-MS

Effects of water scarcity awareness and climate change belief on recycled water usage willingness: Evidence from New Mexico, United States

The global water crisis is being exacerbated by climate change, even in the United States. Recycled water is a feasible alternative to alleviate the water shortage, but it is constrained by humans’ perceptions. The current study examines how residents’ water scarcity awareness and climate change belief influence their willingness to use recycled water directly and indirectly. Bayesian Mindsponge Framework (BMF) analytics was employed on a dataset of 1831 residents in Albuquerque, New Mexico, an arid inland region in the US. We discovered that residents’ willingness to use direct recycled potable water is positively affected by their awareness of water scarcity, but the effect is conditional on their belief in the impacts of climate change on the water cycle. Meanwhile, the willingness to use indirect recycled potable water is influenced by water scarcity awareness, and the belief in climate change further enhances this effect. These findings implicate that fighting climate change denialism and informing the public of the water scarcity situation in the region can contribute to the effectiveness and sustainability of long-term water conservation and climate change alleviation efforts

Preparation of Manganese Dioxide Nanoparticles on Laterite for Methylene Blue Degradation

The laterite-coating manganese dioxide nanoparticle material (M2) prepared by the immersion method was used for the efficient removal of methylene blue (MB) from aqueous solution. The adsorption and heterogeneous Fenton catalytic oxidation experiments of M2 were investigated by changing the effective factors such as time, pH, amount of M2, and concentration of MB. The adsorption data of M2 showed good fitting with the Langmuir isotherm, suggesting that the adsorption of MB on the surface of M2 is a heterogeneous and physical adsorption process. Degradation of MB was also carried out to evaluate the heterogeneous Fenton catalytic oxidation characterization of a new catalytic oxidation material (M2). The results show that the M2 material has both adsorption and heterogeneous Fenton catalytic oxidation. However, the heterogeneous Fenton catalytic oxidation of the M2 material is the main performance. Hence, our groups have investigated the ability of the catalytic column treatment with high efficiency of 98–100% and the degradation efficiency after the sample running through the column almost does not change much. This proves that heterogeneous Fenton catalytic activity of the catalytic column is completely unaffected and reused many times after oxidizing MB. Specifically, even if the M2 material is reused for five times, the degradation efficiency still reaches 98.86%

BINARY HARD-SPHERE COLLOID-DROPLET MIXTURES WITH THE PYRITE-TYPE STRUCTURE

We investigate the assembly of a binary mixture of patchy colloids and droplets into crystal structures by use of the space-filling principle and Metropolis Monte Carlo simulations. Here, colloids with six patches in an octahedral symmetry attract droplets, whereas the colloid-colloid and droplet-droplet pairwise interactions are purely hard-core repulsions. Within parameter space regions that allow for stable binary crystals, we find the formation of different structure types, which are colloidal analogs of the NaCl phase and pyrite (FeS2) phase, as a function of the droplet-to-colloid sphere diameter ratio. This finding is consistent with theoretical predictions. Notably, while the NaCl structure type is a commonly known structure of hard-sphere colloids and nanoparticles, the formation of the FeS2 structure type from colloidal dispersion has not been explored. Our approach suggests a potential route to obtain colloidal crystals with more complex structures

Prediction and optimization of processing parameters in wire and arc-based additively manufacturing of 316L stainless steel

Wire and arc-based additively manufacturing (WAAM) is a potential metallic additively manufacturing (AM) technologies for producing large-size metallic components. 316L is one of the most common stainless-steel grades used in WAAM. However, most of previous studies normally adopted process parameters for the WAAM process based on recommendations of welding wire manufacturers for traditional welding processes. In this article, we focus on predicting and optimizing process parameters for the WAAM process of 316L stainless steel. The experiment was designed by using Taguchi method and L16 orthogonal array. Three parameters, consisting of voltage (U), welding current (I), and travel speed (v), were considered as the input variables, and the responses are four geometrical characteristics of single weld beads, including width, height, penetration, and dilution of weld beads (WWB, HWB, PWB, and DWB, respectively). The effects of each input variable on the responses were determined through analysis of variance (ANOVA). The optimal process parameters were identified by using GRA (grey-relational analysis) and TOPSIS (techniques for order-preferences by similarity-to-ideal solution) methods. The obtained results show that the travel speed has the most important effect on WWB and HWB, while the voltage has the highest impact on PWB and DWD. Both GRA and TOPSIS methods give the same optimum process parameters, namely U = 22 V, I = 110 A, and v = 0.3 m/min, which are validated by confirmation experiments. The predicted models of WWB, HWB, PWB, and DWB were also demonstrated to be adequate for selecting the process parameters in specific applications

Anti-Inflammatory Compounds from Vietnamese Piper bavinum

This study reports the anti-inflammatory activity-guided fractionation of the aerial part of Piper bavinum C. CD. (Piperaceae) that led to the isolation of eight secondary metabolites (1–8). The chemical structures of 1–8 were established mainly by NMR and mass spectra. Compound 5 was isolated from P. bavinum for the first time. All the isolated compounds were evaluated against LPS-induced NO production in macrophage RAW 264.7 cells in vitro. Among them, compound 4 showed the most potent inhibitory activity against the LPS-induced NO production with an IC50 value of 5.2 μM followed by compound 5 that inhibited NO production with an IC50 value of 13.5 μM. In the protein levels, compound 4 suppressed LPS-induced COX-2 and iNOS expressions in a dose-dependent manner. The results suggested that P. bavinum and its constituents might exert anti-inflammatory effects

Histopathological features in the clinical specimens with tuberculosis diagnosis by BACTEC MGIT 960 culture

Diagnosis of extrapulmonary tuberculosis remains challenging in lower-middle income countries with high burden of tuberculosis (TB). This study aims to describe the histological characteristics in biopsy samples from patients with confirmed TB. This is a retrospective study of clinical biopsy specimens with positive liquid medium culture for Mycobacterium tuberculosis and histopathological examination in the National Lung Hospital in Vietnam. Among 1045 biopsy specimens with mycobacteria culture, the overall rate of growth of Mycobacteria tuberculosis in culture was 20.7% (216/1045). The positivity rates of MIGT culture among surgical biopsy specimens were 75% in bone specimen, followed by vertebral specimens (51.3%), and joint specimens (26.4%). For specimens obtained by the fine needle aspiration, the positivity rates of MIGT culture were 26.3% in lymph node and 25.3% in pleural specimen. Among specimens with culture confirmation of TB, the most common histopathoglogical suggestive finding of TB was the presence of epithelioid cell (83.3%), Langhans giant cells (75.9%), and caseous necrosis (75.5%). The high proportion of histological features suggestive of TB among the TB culture confirmed biopsy samples support for further evaluation of histological examination and its combination with other recommended rapid molecular assays in specimens with suspicion of TB

Inhibition of soluble epoxide hydrolase activity by compounds isolated from the aerial parts of <i>Glycosmis stenocarpa</i>

<p>The aim of this study is to search for soluble epoxide hydrolase (sEH) inhibitors from natural plants, bioassay-guided fractionation of lipophilic <i>n</i>-hexane and chloroform layers of an extract of the aerial parts of <i>Glycosmis stenocarpa</i> led to the isolation of 12 compounds (<b>1</b>–<b>12</b>) including murrayafoline-A (<b>1</b>), isomahanine (<b>2</b>), bisisomahanine (<b>3</b>), saropeptate (<b>4</b>), (24 <i>S</i>)-ergost-4-en-3,6-dione (<b>5</b>), stigmasta-4-en-3,6-dion (<b>6</b>), stigmast-4-en-3-one (<b>7</b>), <i>β</i>-sitosterol (<b>8</b>), 24-methylpollinastanol (<b>9</b>), <i>trans</i>-phytol (<b>10</b>), neosarmentol III (<b>11</b>) and (+)-epiloliolide (<b>12</b>). Their structures were elucidated on the basis of spectroscopic data. Among them, neosarmentol III (<b>11)</b> was isolated from nature for the first time. All the isolated compounds were evaluated for their inhibitory activity against sEH. Among isolated carbazole-type compounds, isomahanine (<b>2</b>) and bisisomahanine (<b>3</b>) were identified as a potent inhibitor of sEH, with IC₅₀ values of 22.5 ± 1.7 and 7.7 ± 1.2 µM, respectively. Moreover, the inhibitory action of <b>2</b> and <b>3</b> represented mixed-type enzyme inhibition.</p