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Surface water

Hui Zhao, Jian Zhao, Xingli Sun, Fajin Chen, Guoqi Han
Summer upwelling occurs frequently off the southeast Vietnam coast in the western South China Sea (SCS), where summer phytoplankton blooms generally appear during June-August. In this study, we investigate inter-annual variation of Ekman pumping and offshore transport, and its modulation on summer blooms southeast of Vietnam. The results indicate that there are low intensities of summer blooms in El Niño years, under higher sea surface temperatures (SST) and weaker winds. However, a different pattern of monthly chlorophyll a (Chl-a) blooms occurred in summer of 2007, a transitional stage from El Niño to La Niña, with weak (strong) wind and high (low) SST before (after) early July...
2018: PloS One
T Paulraj, A V Riazanova, A J Svagan
Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility...
January 13, 2018: Acta Biomaterialia
Fausto Martelli, Salvatore Torquato, Nicolas Giovambattista, Roberto Car
We investigate the large-scale structure of amorphous ices and transitions between their different forms by quantifying their large-scale density fluctuations. Specifically, we simulate the isothermal compression of low-density amorphous ice (LDA) and hexagonal ice to produce high-density amorphous ice (HDA). Both HDA and LDA are nearly hyperuniform; i.e., they are characterized by an anomalous suppression of large-scale density fluctuations. By contrast, in correspondence with the nonequilibrium phase transitions to HDA, the presence of structural heterogeneities strongly suppresses the hyperuniformity and the system becomes hyposurficial (devoid of "surface-area fluctuations")...
September 29, 2017: Physical Review Letters
Wilbert J Smit, Fujie Tang, M Alejandra Sánchez, Ellen H G Backus, Limei Xu, Taisuke Hasegawa, Mischa Bonn, Huib J Bakker, Yuki Nagata
Phase-resolved sum-frequency generation measurements combined with molecular dynamics simulations are employed to study the effect of temperature on the molecular arrangement of water on the basal face of ice. The topmost monolayer, interrogated through its nonhydrogen-bonded, free O-H stretch peak, exhibits a maximum in surface H-bond density around 200 K. This maximum results from two competing effects: above 200 K, thermal fluctuations cause the breaking of H bonds; below 200 K, the formation of bulklike crystalline interfacial structures leads to H-bond breaking...
September 29, 2017: Physical Review Letters
Meng Shen, Honghao Li, Monica Olvera de la Cruz
Surface polarization in ion-containing heterogeneous dielectric media such as cell media and emulsions is determined by and determines the positions of the ions. We compute the surface polarization self-consistently as the ions move and analyze their effects on the interactions between electro-neutral, ion-containing droplets using coarse-grained molecular dynamics simulations based on the true energy functional. For water droplets immersed in oil, the interdroplet interaction is attractive, and the surface polarization makes the major contribution...
September 29, 2017: Physical Review Letters
Tyson C Davis, Jae Jin Bang, Jacob T Brooks, David G McMillan, Shelley A Claridge
Noncovalent monolayer chemistries are often used to functionalize 2D materials. Nanoscopic ligand ordering has been widely demonstrated (e.g., lying-down lamellar phases of functional alkanes); however, combining this control with micro- and macroscopic patterning for practical applications remains a significant challenge. A few reports have demonstrated that standing phase Langmuir films on water can be converted into nanoscopic lying-down molecular domains on 2D substrates (e.g., graphite), using horizontal dipping (Langmuir-Schaefer, LS, transfer)...
January 17, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Sheryhan F Gad, Joonyoung Park, Ji Eun Park, Gihan N Fetih, Sozan S Tous, Wooin Lee, Yoon Yeo
Intravenous delivery of poorly water-soluble anticancer drugs such as docetaxel (DTX) is challenging due to the low bioavailability and the toxicity related to solubilizing excipients. Colloidal nanoparticles are used as alternative carriers, but low drug loading capacity and circulation instability limit their clinical translation. To address these challenges, DTX nanocrystals (NCs) were prepared using Pluronic F127 as an intermediate stabilizer and albumin as a functional surface modifier, which were previously found to be effective in producing small and stable NCs...
January 17, 2018: Molecular Pharmaceutics
Yuan Pan, Kaian Sun, Shoujie Liu, Xing Cao, Konglin Wu, Weng-Chon Cheong, Zheng Chen, Yu Wang, Yang Li, Yunqi Liu, Dingsheng Wang, Qing Peng, Chen Chen, Yadong Li
The construction of highly active and stable non-noble metal electrocatalysts for hydrogen and oxygen evolution reactions electrocatalysts is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP na-noparticles (NPs) embedded in N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis-oxidation-phosphidation strategy derived from core-shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances...
January 17, 2018: Journal of the American Chemical Society
Elisabeth Eschlbeck, Christina Seeburger, Ulrich Kulozik
AIMS: To investigate the influence of surface hydrophobicity of carrier material and bacterial spores of Bacillus subtilis SA 22 and Bacillus atrophaeus (DSM 675) on spore inactivation with condensing hydrogen peroxide gas. METHODS AND RESULTS: Surface hydrophobicity of bacterial spores and carrier material was determined by means of contact angle measurement. Spores of Bacillus subtilis showed water contact angles of 90 °, spores of Bacillus atrophaeus showed water contact angles of 42 °...
January 16, 2018: Journal of Applied Microbiology
Nikolay A Simakov, Maria G Kurnikova
The dependency of current-voltage characteristics of the α-hemolysin channel on the channel position within the membrane was studied using Poisson-Nernst-Planck theory of ion conductivity with soft repulsion between mobile ions and protein atoms (SP-PNP). The presence of the membrane environment also influences the protonation state of the residues at the boundary of the water-lipid interface. In this work, we predict that Asp and Lys residues at the protein rim change their protonation state upon penetration to the lipid environment...
January 16, 2018: Journal of Membrane Biology
Jiale Yong, Feng Chen, Jinglan Huo, Yao Fang, Qing Yang, Jingzhou Zhang, Xun Hou
Controlling underwater bubble behavior on a solid surface is of great research significance, particularly in extreme cases. However, the realization of artificial underwater superaerophobic or superaerophilic surfaces is still a challenge. Herein, a micro/nanoscale hierarchical rough structure was formed on polydimethylsiloxane (PDMS) surface by one-step femtosecond laser ablation. The as-prepared surface showed superhydrophobicity in air and superaerophilicity in water. Interestingly, the wettability of such a PDMS surface could be easily switched to in-air superhydrophilicity and underwater superaerophobicity once it was further irradiated by oxygen plasma because the surface chemistry changed...
January 17, 2018: Nanoscale
Hai-Xia Zhang, Yang Li, Min-Yu Li, Huabin Zhang, Jian Zhang
High-performance catalysts for electrocatalytic and photoelectrochemical water splitting hold great promise for renewable energy conversion and storage. Herein, using porous N-doped carbon supported Au nanoparticles as catalysts, we demonstrate that the photon-induced localized surface plasmon resonance (LSPR) excitation on Au nanoparticles dramatically improves the hydrogen evolution reaction (HER), leading to a more than 4-fold increase of current and meanwhile affording a markedly decreased overpotential of 99 mV at a current density of 10 mA cm-2...
January 17, 2018: Nanoscale
Alex P Gaiduk, Tuan Anh Pham, Marco Govoni, Francesco Paesani, Giulia Galli
Understanding redox and photochemical reactions in aqueous environments requires a precise knowledge of the ionization potential and electron affinity of liquid water. The former has been measured, but not the latter. We predict the electron affinity of liquid water and of its surface from first principles, coupling path-integral molecular dynamics with ab initio potentials, and many-body perturbation theory. Our results for the surface (0.8 eV) agree well with recent pump-probe spectroscopy measurements on amorphous ice...
January 16, 2018: Nature Communications
Muhammad Z Ahmad, S Ehtisham-Ul-Haque, Numrah Nisar, Khizar Qureshi, Abdul Ghaffar, Mazhar Abbas, Jan Nisar, Munawar Iqbal
No abstract text is available yet for this article.
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Lihua Sun, Ning He, Xi Duan, Bingbing Yang, Cuimin Feng, Yajun Zhang
The combined processes of powdered activated carbon/biological powdered activated carbon- ultrafiltration (PAC/BPAC-UF) were used to treat secondary effluent. In this study, the effect of PAC and BPAC on membrane flux, membrane resistance and the removal of different molecular weight organic compounds were investigated. In addition, the structure characteristics of the microorganisms of the BPAC were analyzed. The results showed that the optimum dosage of PAC and BPAC was 10 mg/L and 40 mg/L respectively. The reversible membrane fouling resistance of BPAC-UF was higher than that of PAC-UF, and the two processes had the least irreversible resistance at the best dosage...
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Marta Llorca, Gabriella Schirinzi, Mònica Martínez, Damià Barceló, Marinella Farré
Plastic debris has become an environmental problem during recent years. Among the plastic debris, microplastics (<5 mm; MPLs) imply an extra problem due to their capacity to enter into the fauna through ingestion. In this work, we study the capacity of three MPLs, that include high-density polyethylene (HDPE), polystyrene (PS) and polystyrene carboxylate (PS-COOH), to sorb 18 perfluoroalkyl substances (PFASs; including carboxylic acids, sulphonates and one sulphonamide) from the surrounding waters (freshwater and seawater)...
January 12, 2018: Environmental Pollution
A Durán, J M Monteagudo, I San Martín, S Merino
The aim of this work was to evaluate the performance of a novel self-autonomous reactor technology (capable of working with solar irradiation and artificial UV light) for water treatment using aniline as model compound. This new reactor design overcomes the problems of the external mass transfer effect and the accessibility to photons occurring in traditional reaction systems. The UV-light source is located inside the rotating quartz drums (where TiO2 is immobilized), allowing light to easily reach the water and the TiO2 surface...
January 12, 2018: Journal of Environmental Management
Raoul Wolf, Jan-Erik Thrane, Dag Olav Hessen, Tom Andersen
Concentrations of dissolved organic matter (DOM) are increasing in a large number of lakes across the Northern hemisphere. This browning serves a dual role for biota by protecting against harmful ultraviolet radiation, while also absorbing photosynthetically active radiation. The photochemical activation of DOM and subsequent formation of reactive oxygen species (ROS) is a potentially harmful side effect, but can be difficult to measure directly in situ. In this study, we combine a data set of physico-chemical properties from 71 Nordic lakes with in vitro ROS formation quantum yields to predict ROS formations across a representative boreal ecosystem gradient...
January 11, 2018: Water Research
Dongning Wei, Bingyu Li, Hongli Huang, Lin Luo, Jiachao Zhang, Yuan Yang, Jiajun Guo, Lin Tang, Guangming Zeng, Yaoyu Zhou
Nowadays, agricultural contamination is becoming more and more serious due to the rapid growth of agricultural industry, which discharged antibiotics, pesticides or toxic metals into farmlands. A large number of researchers have applied biochar-based functional materials to the treatment of agricultural wastewater contamination. Meanwhile, biochar has also proved to be a very promising and effective technology in water purification field due to its various beneficial properties (e.g., cost effective, high specific surface area, and surface reactive groups)...
January 2, 2018: Chemosphere
C E Egene, R Van Poucke, Y S Ok, E Meers, F M G Tack
To determine the long-term impact of organic amendments on metal (Cd and Zn) immobilization, soil from the Campine region was amended with holm oak-derived biochar, compost, and peat, and monitored over a 3-year period. Pot experiments were conducted by mixing the amendments independently at 2% and 4% (g/g) with the soil. The mobility and solubility of metals in the treatments were assessed by means of rhizon soil moisture samplers, sequential BCR extractions, and diffusive gradient in thin films (DGT). Over the three-year period, the 2% biochar addition resulted in an average decrease in pore water concentration of 40% for Cd and 48% for Zn whereas the 4% addition led to an average decrease of 66% for Cd and 77% for Zn...
January 13, 2018: Science of the Total Environment
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