Ying Ye

Adsorption of Methylene Blue by Rice Hull Ash

Rice hull ash (RHA) is an effective and low-cost adsorbent for water purification. In this study, we systematically investigated the effects of ashing temperature and atmosphere on the physic-chemical characteristics of RHA and its adsorption for methylene blue (MB). XRD, SEM, and BET analyses indicate that all RHA samples are porous materials that consist of carbon and amorphous silica. RHA ashed in nitrogen (BRHA) exhibit higher BET surface areas and lower mesopore fractions than that of ashed in air (WRHA) due to the retention of carbon. The pore volumes and surface area of BRHA increase with ashing temperature, while that of WRHA exhibit a first increase and subsequently decrease. The adsorption kinetics of MB adsorption by RHA fit pseudo-second-order model. The calculated q e values exhibit linear relationships with the mesopore volumes of RHA. The adsorption isotherms fit the Langmuir isotherm rather than the Freundlich equation, indicating the monolayer adsorption of MB. WRHA that ashed at 450°C and BRHA that ashed at 750°C present the highest adsorption capacities for MB with q 0 values of greater than 45 mg g−1. This systematic study will provide essential information on the effects of ashing conditions on the physico-chemical characteristics and dye removal of RHA.

Two Novel Hepatocellular Carcinoma Cycle Inhibitory Cyclodepsipeptides from a Hydrothermal Vent Crab-Associated Fungus Aspergillus clavatus C2WU

Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a d-phenyllactic acid residues, clavatustides A (1) and B (2), were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich hydrothermal vents in Taiwan Kueishantao. This is the first example of cyclopeptides containing an anthranilic acid dimer in natural products, and the first report of microbial secondary metabolites from the hydrothermal vent crab. Clavatustides A (1) and B (2) suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase.

Synergistic effect of combined colloidal and organic fouling in membrane distillation: Measurements and mechanisms

We examined the synergistic effect of combined fouling in MD process with three organic foulants – alginate, bovine serum albumin (BSA), and humic acid – in the presence of colloidal silica particles. Membrane fouling profiles were quantified by water flux decline and permeate conductivity. Mechanisms of the synergistic effect of combined fouling were revealed by light scattering measurements and infrared spectra of foulant–foulant interaction and foulant–membrane interaction. Membrane fouling morphology and element mapping provided further details of transport of colloidal silica particles and elucidated the mechanisms for silica-induced pore wetting. Specially, gelation of alginate formed an alginate layer on membrane surface and prevented penetration of silica particles into the membrane matrix, which was confirmed by silicon element mapping as well as infrared spectra. Adsorption of BSA protein by colloidal silica aggregates led to a sharp water flux decline and a partial pore wetting. Humic acid, forming a coil structure in high salinity, exhibited limited interaction with colloidal silica that penetrated into the membrane matrix and wetted membrane pores, thereby compromising the product water quality. Results showed that the combined organic fouling with colloidal silica particle not only deteriorated water production, but also compromised product quality by partial membrane wetting.

Facile preparation of MnFe2O4/halloysite nanotubular encapsulates with enhanced magnetic and electromagnetic performances

We synthesized novel magnetic nanotubular encapsulates with ferrite nanoparticles embedded into the inner channels of halloysite nanotubes (HNTs) for the first time. The nano-encapsulates with enclosed ferrite nanoparticles show significantly enhanced magnetic and electromagnetic performance when compared to that with external particles.

Zn-Driven Discovery of a Hydrothermal Vent Fungal Metabolite Clavatustide C, and an Experimental Study of the Anti-Cancer Mechanism of Clavatustide B

A naturally new cyclopeptide, clavatustide C, was produced as a stress metabolite in response to abiotic stress elicitation by one of the hydrothermal vent fluid components Zn in the cultured mycelia of Aspergillus clavatus C2WU, which were isolated from Xenograpsus testudinatus. X. testudinatus lives at extreme, toxic habitat around the sulphur-rich hydrothermal vents in Taiwan Kueishantao. The known compound clavatustide B was also isolated and purified. This is the first example of a new hydrothermal vent microbial secondary metabolite produced in response to abiotic Zn treatment. The structures were established by spectroscopic means. The regulation of G1-S transition in hepatocellular carcinoma cell lines by clavatustide B was observed in our previous study. The purpose of the present study was to verify these results in other types of cancer cell lines and elucidate the possible molecular mechanism for the anti-cancer activities of clavatustide B. In different human cancer cell lines, including pancreatic cancer (Panc-1), gastric cancer (MGC-803), colorectal cancer (SW-480), retinoblastoma (WERI-Rb-1) and prostate cancer (PC3), clavatustide B efficiently suppressed cell proliferations in a dose-dependent manner. Although different cancer cell lines presented variety in Max effect dose and IC50 dose, all cancer cell lines showed a lower Max effect dose and IC50 dose compared with human fibroblasts (hFB) (p < 0.05). Moreover, significant accumulations in G1 phases and a reduction in S phases (p < 0.05) were observed under clavatustide B treatment. The expression levels of 2622 genes including 39 cell cycle-associated genes in HepG2 cells were significantly altered by the treatment with 15 μg/mL clavatustide B after 48 h. CCNE2 (cyclin E2) was proved to be the key regulator of clavatustide B-induced G1-S transition blocking in several cancer cell lines by using real-time PCR.

Stress-driven discovery of a cryptic antibiotic produced by Streptomyces sp. WU20 from Kueishantao hydrothermal vent with an integrated metabolomics strategy

Marine hydrothermal microorganisms respond rapidly to the changes in the concentrations and availability of metals within hydrothermal vent microbial habitats which are strongly influenced by elevated levels of heavy metals. Most hydrothermal vent actinomycetes possess a remarkable capability for the synthesis of a broad variety of biologically active secondary metabolites. Major challenges in the screening of these microorganisms are to activate the expression of cryptic biosynthetic gene clusters and the development of technologies for efficient dereplication of known compounds. Here, we report the identification of a novel antibiotic produced by Streptomyces sp. WU20 isolated from the metal-rich hydrothermal vents in Taiwan Kueishantao, following a strategy based on metal induction of silent genes combined with metabolomics analytical methods. HPLC-guided isolation by tracking the target peak resulted in the characterization of the novel compound 1 with antimicrobial activity against Bacillus subtilis. The stress metabolite 1 induced by nickel is structurally totally different compared with the normally produced compounds. This study underlines the applicability of metal induction combined with metabolic analytical techniques in accelerating the exploration of novel antibiotics and other medically relevant natural products.

An Unusual Stress Metabolite from a Hydrothermal Vent Fungus Aspergillus sp. WU 243 Induced by Cobalt

A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment.A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment.A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao hydrothermal vents off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from hydrothermal vent fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the hydrothermal vent environment.

Distribution and Geochemical Characteristics of Fluids in Ordovician Marine Carbonate Reservoirs of the Tahe Oilfield

The Ordovician carbonate reservoirs in the Tahe Oilfield are highly heterogeneous, which have undergone multiple superimposed transformations by tectonic activities and karst processes, leading to an extremely complex fluid distribution. The geochemical characteristics of geofluids also display great disparities. Results show that the vertical distribution of oil and gas are continuous, however the oil-water interfaces in different blocks of the Tahe Ordovician Oilfield are numerous. Meteoric water infiltration is regarded as the main reason for the high oil-water interface and high water content to the north of Tahe Oilfield, especially in well blocks S78−S73. The isotopic values of deuterium-oxygen in the groundwater and carbon-oxygen from calcite veins confirm that formation water in Ordovician reservoirs of the Tahe Oilfield was a mix of meteoric water and connate water, and the proportion of meteoric water gradually increases from south to north, while connate water decreases. The Tahe Ordovician reservoirs are characterised by multiple hydrocarbon charges, and the general migrating direction is from southeast to northwest and from east to west. High production could be obtained in the northern area of the Tahe Oilfield since the oil layers are thick and oil is highly saturated. The residual water within the reservoirs is low, and heavy oil is dominant in this area. Only a small amount of pore water has been replaced by oil in the southern Tahe Oilfield, leading to low oil saturation and a high content of residual water. Crude oil is herein mainly of medium-light type. During the process of exploration in this region, acid fracturing reformation is usually required for wells to increase their output; however the yield is still low.

A novel Cu+-doped Li[Fe0.9Cu0.1Li0.1]PO4/C cathode material with enhanced electrochemical properties

LiFePO4 is an effective battery material which has gained global focus. In this study, we prepared a novel Cu+-doped Li[Fe0.9Cu0.1Li0.1]PO4/C cathode material via a carbothermal reduction method using glucose as carbon source. X-ray diffraction (XRD) patterns and Rietveld refinement on the samples are consistent with the orthorhombic phase and showed that the substituting Cu+ ions and excess Li+ ions occupy the Fe sites. The micro-morphology of the samples indicates that Cu+ doping can decrease the particle size and maintain the crystal structure of LiFePO4/C. XP spectra confirmed that the surface oxidation states of Fe and Cu are +2 and +1, respectively. The as-prepared Li[Fe0.9Cu0.1Li0.1]PO4/C composite exhibits enhanced initial discharge capacity (148.8 mA h g−1) compared to the un-doped LiFePO4/C. The discharge capacity remains at 149.8 mA h g−1 after 50 cycles at a rate of 0.2C, which displayed an excellent cycling stability. Furthermore, the cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) results showed that the Cu+-doped LiFePO4/C composite exhibits a higher lithium-ion diffusion coefficient and lower charge transfer resistance than the undoped counterparts. This study presents a novel Cu+-doped LiFePO4/C cathode material with enhanced electrochemical properties, which could be potentially applied as a battery material.

PREPARATION AND MICROWAVE ABSORPTION OF MICRO-FIBROUS Fe/C NANOCOMPOSITE

Wide-band absorption with low density is essential for microwave absorbers. We fabricated a novel micro-fibrous Fe/C nanocomposite with bulk density of only 0.47 ± 0.03 g cm-3 using carbonized cotton fibers as template. Monodisperse iron nanoparticles with diameter of about 100 nm covered on the fibers and significantly increased the complex permittivity and permeability, and therefore enhanced the reflection loss (RL) for electromagnetic waves. The optimum thickness for the nanocomposite is 1.5–1.8 mm, with maximum RL of -14 dB and bandwidth of RL < -5 dB from 10 to 18 GHz, similar to that of Fe/C nanocomposite without using carbonized cotton fibers. Because of its low density and broad bandwidth at thin matching thickness, micro-fibrous Fe/C nanocomposite is a promising light-weight microwave absorber.