SciCombinator

Discover the most talked about and latest scientific content & concepts.

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Highly caffeinated energy drinks (EDs) are popular with adolescents and young adults, but longitudinal consumption patterns are poorly understood especially in relation to other substance use.

Concepts: Jolt Cola, Soft drink, Red Bull, Guarana, Coca-Cola, Coffee, Energy drink, Caffeine

23

Proper treatment of waste-activated sludge (WAS) involves three pivotal processes, dewatering, anaerobic digestion, and pollutants removal, which need to be re-assessed urgently. Although many traditional sludge treatments have been developed, it is prudent to enhance the efficiency of sludge treatment using multifunctional, flexible, and environmentally friendly surfactants. With regard to sludge dewatering, surfactants can weaken the binding interaction between sludge flocs and promote the dissolution of extracellular polymeric substances (EPSs), resulting in the release of bound water. Using surfactants in anaerobic digestion promotes the release of enzymes trapped in sludge and improves the activity of enzymes during hydrolysis. Owing to their characteristic encapsulation of hydrophobes into self-assembled aggregates (micelles), surfactants can form host-guest complexes with polycyclic aromatic hydrocarbons (PAHs). Additionally, surfactants can enhance the desorption of heavy metals and prevent the emergence of heavy metal residue. This review summarizes the current surfactant-based sludge treatment technologies according to their roles in sludge disposal solutions. Then, possible mechanisms of surfactants in sludge dewatering, anaerobic digestion, and the removal of organic pollutants and heavy metals are analysed systemically. Finally, changes to sludge treatment via the aid of surfactants are highlighted. This review presents the comprehensive advances in the use of surfactants in WAS reduction, recycling, and risk relief, underscoring their roles in increasing economic efficiency and ensuring environmental quality.

Concepts: Aromaticity, Tungsten, Anaerobic digestion, Heavy metal, Protein, Environment, Polycyclic aromatic hydrocarbon, Heavy metal music

23

A 54-year-old African-American man presented with 2 years of progressively worsening dyspnea and anasarca. Over the past 6 months he gained 30 lbs with worsening lower extremity, abdominal wall, and scrotal edema. A recent workup for cardiac, renal, and liver disease, including two-dimensional echocardiogram, liver and renal function tests, and abdominal ultrasound, was unremarkable. He reported a 15-pack year history of smoking and quit 3 years ago. Chest radiograph at that time revealed bilateral pleural effusions that were both reportedly milky in appearance when drained by thoracenteses.

Concepts: Abdominal cavity, Organ, Medical imaging, Thorax, Peritoneum, Liver function tests, Pleural effusion

23

Given its proximity to northern Africa, southern Spain is regularly affected by high-altitude African intrusions. This determines a well-defined wind dynamics at surface levels. Although this weather event-mainly recorded in spring and summer-coincides with the flowering season of many wind pollinated species, its potential influence on long term airborne pollen transport has been not investigated in detail. We analyse their influence on olive pollen transport at surface level in south Spain. Daily and bi-hourly olive pollen data from 2010 to 2015, recorded at two sites 150km apart, Málaga (coast) and Córdoba (inland), were analysed together with 1) air masses at 300m above ground level (m.a.g.l.), 2) surface wind direction and 3) surface wind speed over the same period. Air masses at 3000m.a.g.l. were used to identify the periods under the influence of African intrusions. The combined analysis has enabled the identification of different pollen patterns and source contributions. In Málaga, hourly pollen peaks were recorded during the early morning coinciding with the arrival of north-westerly winds (developing sea-land breezes), with a minimal impact of local pollen sources; in Córdoba, by contrast, pollen concentrations reflected the joint contribution of local and long term sources, being the maximum concentrations associated with the arrival of southerly air masses in the afternoon. These results help to understand the potential distant sources and back-trajectories of olive pollen detected. In our case pollen from sources located at the west-northwest areas in the case of Malaga, and from the south in Cordoba. These results reinforce the idea that combined studies between synoptic meteorological and aerobiological data together with different atmospheric height air masses data, offer us a better explanation and understanding of the behaviour and the potential sources of recorded airborne data in a given place.

Concepts: Wind power, Southern United States, Transport, Meteorology, Wind speed, Weather, Spain, Wind

0

Lithium sulfur battery is considered as a prospective candidate for high-energy-storage system as its high theoretical specific capacity and energy. However, the dissolution and shutter of polysulfides lead to low active material utilization and fast capacity fading. Electrospinning technology is employed to directly coat an interlayer composed of polyacrylonitrile (PAN) and nitrogen-doped carbon black (NC) fibers on the cathode. Benefited from electrospinning technology, the PAN-NC fibers possess good electrolyte infiltration for fast lithium-ion transport and great flexibility for adhering on the cathode. The NC particles provide good affinity for polysufides and great conductivity. Thus the polysulfides can be trapped on the cathode and well reutilized. As a result, the PAN-NC coated sulfur cathode (PAN-NC@Cathode) exhibits the initial discharge capacity of 1279 mAh g-1, and remains reversible capacity of 1030 mAh g-1 with capacity fading of 0.05% per cycle at 200 mA g-1 after 100 cycles. Adopting electrospinning to directly form fibers on the cathode shows a promising application.

Concepts: Lithium battery, English-language films, Lithium, Specific heat capacity, Polysulfide, Rechargeable battery, Carbon, Battery

0

Surface functionalization is very effective in enhancing sensing properties of a chemiresistive gas sensor. In this work, we develop a novel and cost-effective process to prepare Ag-modified silicon nanowire (SiNW) sensors and further suggest a resistance effect model to clarify the enhanced sensing mechanism of Ag-modified SiNWs. The SiNWs were formed via metal-assisted chemical etching (MACE), and the Ag nanoparticle (NP) modification was achieved in situ based on the MACE-produced Ag dendrites by involving a crucial anisotropic postetching of TMAH. The TMAH etching induces a loose array of needle-like, rough SiNWs (RNWs) with firm attachment of tiny Ag NPs. Comparative investigations for NH3-sensing properties indicate that the RNWs modified by discrete Ag NPs (Ag@RNWs) display an ∼3-fold enhancement in gas response at room temperature compared with pristine SiNWs. Meanwhile, transient response and ultrafast recovery are observed for the Ag@RNW sensor (tres ≤ 2 s and trec ≤ 9 s to 0.33-10 ppm of NH3). The study demonstrates the considerable effect and potential of the Ag modification process developed in this work. A resistance effect model was further suggested to clarify the underlying mechanism of the enhanced response and the response saturation characteristic of the Ag@RNWs. The promotion of TMAH etching-induced microstructure modulation to sensing properties was also demonstrated.

Concepts: Nanowire battery, Etching, In situ, Effectiveness, Suggestion, Demonstration, Sensor, Materials science

0

A novel light but strong SiC foam with hierarchical porous architecture are fabricated by using dough as raw material via carbonization and followed carbothermal reduction with silicon source. A significant synergistic effect is achieved by embedding meso and nano pores in micro-sized porous skeleton, which endows the SiC foam with high-performance electromagnetic interference shielding (EMI), thermal insulation and mechanical properties. The micro-sized skeleton withstands the high stress. The meso- and nano-sized pores enhance the multiple reflection of the incident electromagnetic waves and elongate the path of heat transfer. For the hierarchical porous SiC foam with 72.8% porosity, EMI shielding can be higher than 20 dB and specific EMI effectiveness exceeding 24.8 dB cm3 g-1 in the frequency of 11 GHz at 25-600 °C, which is 3 times higher than dense SiC ceramic. The thermal conductivity reaches as low as 0.02 W m-1 K-1, which is comparable to aerogel. But the compressive strength is as high as 9.8 MPa. Considering the chemical and high-temperature stability of SiC, the fabricated SiC foam is a promising candidate for modern aircraft and automobile applications.

Concepts: Electromagnetic interference, Electromagnetic radiation, Thermal insulation, Wave, Light, Wavelength, Heat transfer, Heat

0

Entry inhibitors are emerging as an attractive class of therapeutics for hepatitis C virus (HCV) infection. Entry inhibitors target either virion-associated factors or cellular factors necessary for infection. By blocking entry into cells, entry inhibitors prevent both the establishment of persistent reservoirs and the emergence of resistant variants during viral replication. Furthermore, entry inhibitors protect naïve cells from virus-induced alterations. Combining entry inhibitors with direct-acting antivirals (DAAs) may therefore improve treatment outcomes, particularly in the context of organ transplantation. The role of DAAs in transplantation, while still under clinical investigation, carries the risk of recipient infection and HCV-induced disease, since DAAs act only after infection is established. Thus, entry inhibitors provide a perspective to improve patient outcomes during organ transplantation. Applying this approach for transplant of organs from HCV-positive donors to HCV-negative recipients may also contribute to alleviate the medical burden of organ shortage.

Concepts: Bacteria, Organelle, Virus, Microbiology, Hepatitis C virus, Organ, Hepatitis C, Organ transplant

0

An antifouling ethylene-vinyl acetate copolymer (EVA) with halloysite clay nanotubes loaded with maleimide (TCPM) is prepared. Such encapsulation allowed for extended release of TCPM and a long-lasting, efficient protection of the coated surface against marine microorganisms proliferation. Halloysite also induces the composite’s anisotropy due to parallel alignment of the nanotubes. The maleimide loaded halloysite incorporated into the polymer matrix allowed for 12-month release of the bacterial inhibitor preventing fouling; it is much longer than the 2-3 month protection when TCPM is directly admixed into EVA. The antifouling properties of the EVA-halloysite nanocomposites were tested by monitoring surface adhesion and proliferation of marine V. natriegens bacteria with SEM. As compared to the composite directly doped with TCPM-antifoulant, there were much less bacteria accumulated on the EVA-halloysite-TCPM coating after a two-month exposure to sea water. Field tests at South China Sea marine station further confirmed the formulation efficiency. The doping of 28 wt. % TCPM loaded halloysite drastically enhanced material antifouling property which promises wide applications for protective marine coating.

Concepts: Ethylene-vinyl acetate, Water, Archaea, Composite material, Microorganism, Bacteria, South China Sea, Polymer

0

Scalable manufacturing of flexible, fiber-shaped energy storage devices has enabled great technological advances in wearable and portable technology. Replacing inefficient oxides with inexpensive and high-performance oxynitrides with more favourable 3D structures is critical if the practical applications of these technologies are to be realised. Here we developed a facile and controllable approach for the synthesis of 3D porous micropillars of molybdenum oxynitride, which exhibit high conductivity, robust stability and excellent energy storage properties. Our fiber electrode, containing a 3D hierarchical molybdenum oxynitride (MON)-based anode, yields remarkable linear and areal specific capacitances of 64.8 mF cm-1 and 736.6 mF cm-2, respectively, at a scan rate of 10 mV s-1. Moreover, a wearable asymmetric supercapacitor based on TiN/MON//TiN/MnO2 demonstrates good cycling stability with a linear capacitance of 12.7 mF cm-1 at a scan rate of 10 mV s-1. These remarkable electrochemical properties are mainly attributed to the synergistic effect between the chemical composition of oxynitride and the robust 3D porous structure composed of interconnected nanocrystalline morphology. The presented strategy for the controllable design and synthesis of novel-oxide-derived functional materials offers prospects in developing portable and wearable electronic devices. We also demonstrate that these fiber supercapacitors can be combined with an organic solar cell to construct a self-powered system for broader applications.

Concepts: Energy conversion, Flywheel energy storage, Battery, Electrochemistry, Technology, Solar cell, Capacitor, Diode