Effect of Natural Nanostructured Rods and Platelets on Mechanical and Water Resistance Properties of Alginate-Based Nanocomposites

A series of biopolymer-based nanocomposite films were prepared by incorporating natural one-dimensional (1D) palygorskite (PAL) nanorods, and two-dimensional (2D) montmorillonite (MMT) nanoplatelets into sodium alginate (SA) film by a simple solution casting method. The effect of different dimensions of nanoclays on the mechanical, water resistance, and light transmission properties of the SA/PAL or MMT nanocomposite films were studied. The field-emission scanning electron microscopy (FE-SEM) result showed that PAL can disperse better than MMT in the SA matrix in the case of the same addition amount. The incorporation of both PAL and MMT into the SA film can enhance the tensile strength (TS) and water resistance capability of the film. At a high content of nanoclays, the SA/PAL nanocomposite film shows relatively higher TS, and better water resistance than the SA/MMT nanocomposite film. The SA/MMT nanocomposite films have better light transmission than SA/PAL nanocomposite film at the same loading amount of nanoclays. These results demonstrated that 1D PAL nanorods are more suitable candidate of inorganic filler to improve the mechanical and water resistance properties of biopolymers/nanoclays nanocomposites

Pressure-stabilized divalent ozonide CaO3 and its impact on Earth's oxygen cycles.

High pressure can drastically alter chemical bonding and produce exotic compounds that defy conventional wisdom. Especially significant are compounds pertaining to oxygen cycles inside Earth, which hold key to understanding major geological events that impact the environment essential to life on Earth. Here we report the discovery of pressure-stabilized divalent ozonide CaO3 crystal that exhibits intriguing bonding and oxidation states with profound geological implications. Our computational study identifies a crystalline phase of CaO3 by reaction of CaO and O2 at high pressure and high temperature conditions; ensuing experiments synthesize this rare compound under compression in a diamond anvil cell with laser heating. High-pressure x-ray diffraction data show that CaO3 crystal forms at 35 GPa and persists down to 20 GPa on decompression. Analysis of charge states reveals a formal oxidation state of -2 for ozone anions in CaO3. These findings unravel the ozonide chemistry at high pressure and offer insights for elucidating prominent seismic anomalies and oxygen cycles in Earth's interior. We further predict multiple reactions producing CaO3 by geologically abundant mineral precursors at various depths in Earth's mantle

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Removal of Cu and Zn Ions from Aqueous Solution Using Sodium Alginate and Attapulgite Composite Hydrogels

A series of sodium alginate-g-sodium acrylate/attapulgite (NaAlg-g-PNaA/APT) composite hydrogels were used as adsorbents to adsorb Cu 2+ and Zn 2+ from aqueous solutions. The effect of common variables including the content of APT, pH value, contact time and initial concentration of metal ions on the adsorption properties of the composite hydrogels for the adsorption of Cu 2+ and Zn 2+ ions was investigated using a batch adsorption technique. The results show that the composites evaluated have an excellent adsorption capacity and fast adsorption rate for both Cu 2+ and Zn 2+ ions. Repeated adsorption–desorption experimental results show that the composite hydrogels have a good reusability and stability, and 50% of the original adsorption capacity can be retained after being reused five times. The pseudo-second-order equation and the Langmuir equation best describe the adsorption kinetics and isotherms, respectively

Reducing Water Sensitivity of Chitosan Biocomposite Films Using Gliadin Particles Made by In Situ Method

In order to sustain rapid expansion in the field of biocomposites, it is necessary to develop novel fillers that are biodegradable, and easy to disperse and obtain. In this work, gliadin particles (GPs) fabricated through an in situ method have been reported as fillers for creating chitosan (CS)-based biocomposite films. In general, the particles tend to agglomerate in the polymer matrix at high loading (approximately >10%) in the biopolymer/particles composites prepared by the traditional solution-blending method. However, the micrographs of biocomposites confirmed that the GPs are well dispersed in the CS matrix in all CS/GPs composites even at a high loading of 30% in this study. It was found that the GPs could improve the mechanical properties of the biocomposites. In addition, the results of moisture uptake and solubility in water of biocomposites showed that water resistance of biocomposites was enhanced by the introduction of GPs. These results suggested that GPs fabricated through an in situ method could be a good candidate for use in biopolymer-based composites

Survival strategies of phytoplankton functional groups to environmental factors in a drinking water reservoir, central China

In this study, use survival strategies of phytoplankton functional groups to environmental factors in a drinking water reservoir. Survival strategies of phytoplankton in drinking water reservoirs were rarely analysed. Dynamics and survival strategies of phytoplankton community in Zhushuqiao Reservoir (Changsha, China) were studied bimonthly from April 2016 to February 2017 to fill this gap. In spring, species of CRS-strategy that adapted to low water temperature, light, and nutrient dominated. There were small individuals of opportunistic colonists of C-strategy observed before stratification. With the increase of nutrient and water temperature in summer, slightly bigger, disturbance-tolerant species of R-strategy and species of CS-strategy that adapted to stratification dominated. In winter, some species adapted to low water temperature, which were R-strategists. Key factors driven seasonal phytoplankton succession were water temperature, total phosphorus, and dissolved inorganic nitrogen. Attention should be paid to potential threats from algal bloom species with C-strategy, and future longer-term monitoring of the system and its surrounding watersheds is greatly needed.In this study, we used the phytoplankton functional group index, survival strategies and environmental conditions in the Zhushuqiao reservoir to detect overall phytoplankton survival strategies (C-S-R) in the entire reservoir water column, and assess quantitative relationships between phytoplankton survival strategies and environment, which may help for future reservoir management

Seasonal succession of phytoplankton functional groups in a reservoir in central China

Zhushuqiao Reservoir is one of the main sources of drinking water for Changsha City, which is the capital of Hunan province in central China. Understanding phytoplankton functional groups and their relationships with the environment is critical for the sustainable management of the reservoir for the supply of drinking water. Therefore, phytoplankton and water samples were collected and analyzed seasonally in 2016 to detect these relationships, with a total of 23 functional groups of phytoplankton identified. The highest diversity of functional groups was observed in spring, while the lowest was in winter. Due to differences in the geographical position, as well as the hydrological and environmental conditions, upstream phytoplankton-community structures are different from those downstream, with the dominant functional groups having a clear seasonal succession. The succession dynamics of phytoplankton functional groups from upstream to downstream in spring were M (Microcystis aeruginosa) + Y (Cryptomonas sp.) -> S1 (Pseudanabaena limnetica) + L-M (Gomphosphaeria sp.) -> S1 + L-M + X1 (Chlorella sp.) -> X1 + X2 (chlamydomonas sp.) + F (Oocystis sp.) -> F + X1 + X2; X1, F and Lo (Peridinium sp.) were the co- dominant groups from summer to autumn, and group C (Melosira ambigua) was dominant in winter. The upstream assemblages of X1 + X2, X1 + F, S1 + L-M + M in spring and LO in summer can adapt to the rapid growth in eutrophic conditions with potential bloom threats. Water temperature, light and phosphorus were the primary factors regulat- ing the dominant functional groups, and the phytoplankton succession was seasonally dependent. These results may have implications for the management of future water resources in the Zhushuqiao Reservoir, such as the determination of the intake depth of drinking water, and the prevention of nutrient pollution

Seasonal succession of phytoplankton functional groups in a reservoir in central China

Zhushuqiao Reservoir is one of the main sources of drinking water for Changsha City, which is the capital of Hunan province in central China. Understanding phytoplankton functional groups and their relationships with the environment is critical for the sustainable management of the reservoir for the supply of drinking water. Therefore, phytoplankton and water samples were collected and analyzed seasonally in 2016 to detect these relationships, with a total of 23 functional groups of phytoplankton identified. The highest diversity of functional groups was observed in spring, while the lowest was in winter. Due to differences in the geographical position, as well as the hydrological and environmental conditions, upstream phytoplankton-community structures are different from those downstream, with the dominant functional groups having a clear seasonal succession. The succession dynamics of phytoplankton functional groups from upstream to downstream in spring were M (Microcystis aeruginosa) + Y (Cryptomonas sp.) -> S1 (Pseudanabaena limnetica) + L-M (Gomphosphaeria sp.) -> S1 + L-M + X1 (Chlorella sp.) -> X1 + X2 (chlamydomonas sp.) + F (Oocystis sp.) -> F + X1 + X2; X1, F and Lo (Peridinium sp.) were the co- dominant groups from summer to autumn, and group C (Melosira ambigua) was dominant in winter. The upstream assemblages of X1 + X2, X1 + F, S1 + L-M + M in spring and LO in summer can adapt to the rapid growth in eutrophic conditions with potential bloom threats. Water temperature, light and phosphorus were the primary factors regulat- ing the dominant functional groups, and the phytoplankton succession was seasonally dependent. These results may have implications for the management of future water resources in the Zhushuqiao Reservoir, such as the determination of the intake depth of drinking water, and the prevention of nutrient pollution

Synergistic Effect of Halloysite Nanotubes and Glycerol on the Physical Properties of Fish Gelatin Films

Fish gelatin (FG)/glycerol (GE)/halloysite (HT) composite films were prepared by casting method. The morphology of the composite films was observed by scanning electron microscopy (SEM). The effects of HT and GE addition on the mechanical properties, water resistance and optical properties of the composites were investigated. Results showed that with increasing GE content, the elongation at composite breaks increased significantly, but their tensile strength (TS) and water resistance decreased. SEM results showed that GE can partly promote HT dispersion in composites. TS and water resistance also increased with the addition of HTs. Well-dispersed HTs in the FG matrix decreased the moisture uptake and water solubility of the composites. All films showed a transparency higher than 80% across the visible light region (400⁻800 nm), thereby indicating that light transmittance of the resulting nanocomposites was slightly affected by GE and HTs