SciCombinator

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

Journal: Small (Weinheim an der Bergstrasse, Germany)

167

By combining upconversion nanoparticles (UCNPs) with rhodamine 6G (R6G) dye molecules, multicolor emission based on energy transfer is achieved. The complexes can be dissolved in epoxy resin, and self-assembled hemispherical microstructures are fabricated through a hydrophobic effect. A luminescence temperature sensor takes advantage of the high temperature sensitivity of the complexes due to energy transfer.

Concepts: Light, Temperature, Thermodynamics, Signal processing, Dye laser, Sensor, Rhodamine dyes, Rhodamine 6G

30

Stripes on gold nanoparticles were previously reported [Nature Materials, 3, 2004]. In subsequent articles, unusual physicochemical and biological properties were attributed to these particles. Here, the evidence supporting the existence of the stripy nanoparticles is critically revisited. Using simple geometrical arguments, fast-Fourier transform and experimental investigations, we conclude that the observed stripes are an imaging artifact.

Concepts: Critical thinking, Nanoparticle, Life, Gold, Philosophy of science, Nature, Artifact

29

Based on soft-touch atomic force microscopy, a method is described to reconstruct the secondary structure of single extended biomolecules, without the need for crystallization. The method is tested by accurately reproducing the dimensions of the B-DNA crystal structure. Importantly, intramolecular variations in groove depth of the DNA double helix are resolved, which would be inaccessible for methods that rely on ensemble-averaging.

Concepts: DNA, Protein, Gene, Crystal, Crystallography, Organism, Biochemistry, Double helix

29

The static and dynamic wetting properties of a 3D graphene foam network are reported. The foam is synthesized using template-directed chemical vapor deposition and contains pores several hundred micrometers in dimension while the walls of the foam comprise few-layer graphene sheets that are coated with Teflon. Water contact angle measurements reveal that the foam is superhydrophobic with an advancing contact angle of ∼163 degrees while the receding contact angle is ∼143 degrees. The extremely water repellent nature of the foam is also confirmed when impacting water droplets are able to completely rebound from the surface. Such superhydrophobic graphene foams show potential in a variety of applications ranging from anti-sticking and self-cleaning to anti-corrosion and low-friction coatings.

Concepts: Water, Wetting, Surface tension, Chemical vapor deposition, Angle, Contact angle, Coatings, Sessile drop technique

29

A bulk metallic glass (BMG) micro fuel cell displays advantages over traditional micro fuel cell designs in terms of performance and fabrication. The BMG gas flow fields are durable and shock and corrosion resistant, and the Pt-BMG catalytic layers (including Pt-BMG nanowires) are promising candidates for use in micro fuel cells.

Concepts: Electrochemistry, Carbon, Metal, Solid, Electrolysis, Fuel cell, Corrosion, Amorphous metal

28

In contrast to pristine zinc phthalocyanine (1), zinc phthalocyanine based oPPV-oligomers (2-4) of different chain lengths interact tightly and reversibly with graphite, affording stable and finely dispersed suspensions of mono- to few-layer graphene-nanographene (NG)-that are photoactive. The p-type character of the oPPV backbones and the increasing length of the oPPV backbones facilitate the overall π-π interactions with the graphene layers. In NG/2, NG/3, and NG/4 hybrids, strong electronic coupling between the individual components gives rise to charge transfer from the photoexcited zinc phthalocyanines to NG to form hundreds of picoseconds lived charge transfer states. The resulting features, namely photo- and redoxactivity, serve as incentives to construct and to test novel solar cells. Solar cells made out of NG/4 feature stable and repeatable photocurrent generation during several ‘on-off’ cycles of illumination with monochromatic IPCE values of around 1%.

Concepts: Photoelectric effect, Cadmium, Solar cell, Photovoltaics, Length, Photovoltaic module, Band gap, Phthalocyanine

28

Nanomaterials (NMs) are engineered for commercial purposes such as semiconductors, building materials, cosmetics, and drug carriers, while natural nanoparticles (NPs) already exist in the environment. Due to their unique physicochemical properties, they may interact actively with biological systems. Some of these interactions might be detrimental to human health, and therefore studies on the potential ‘nanotoxicity’ of these materials in different organ systems are warranted. The purpose of developing the concept of nanotoxicity is to recognize and evaluate the hazards and risks of NMs and evaluate safety. This review will summarize and discuss recent reports derived from cell lines or animal models concerning the effects of NMs on, and their application in, the endocrine system of mammalian and other species. It will present an update on current studies of the effects of some typical NMs-such as metal-based NMs, carbon-based NMs, and dendrimers-on endocrine functions, in which some effects are adverse or unwanted and others are favorable or intended. Disruption of endocrine function is associated with adverse health outcomes including reproductive failure, metabolic syndrome, and some types of cancer. Further investigations are therefore required to obtain a thorough understanding of any potential risk of pathological endocrine disruption from products containing NMs. This review aims to provide impetus for further studies on the interactions of NMs with endocrine functions.

Concepts: Human, Nutrition, Biology, Life, Endocrinology, Nanotechnology, Endocrine system, Endocrine disruptor

28

MoS(2) nanosheet-coated TiO(2) nanobelt heterostructures-referred to as TiO(2) @MoS(2) -with a 3D hierarchical configuration are prepared via a hydrothermal reaction. The TiO(2) nanobelts used as a synthetic template inhibit the growth of MoS(2) crystals along the c-axis, resulting in a few-layer MoS(2) nanosheet coating on the TiO(2) nanobelts. The as-prepared TiO(2) @MoS(2) heterostructure shows a high photocatalytic hydrogen production even without the Pt co-catalyst. Importantly, the TiO(2) @MoS(2) heterostructure with 50 wt% of MoS(2) exhibits the highest hydrogen production rate of 1.6 mmol h(-1) g(-1) . Moreover, such a heterostructure possesses a strong adsorption ability towards organic dyes and shows high performance in photocatalytic degradation of the dye molecules.

Concepts: Chemical reaction, Hydrogen, Catalysis, Atom, Chemical bond, Dye, Heterojunction, Hydrogen production

28

Calcium manganese oxide nanoparticles for application in water oxidation are synthesized by combination with a carboxylated biopolymer stabilizing agent to form very simple but effective analogues of the photosynthetic PSII oxygen evolving complex. The relative efficiency of these materials for production of O(2) and protons under visible light-promoted reactions is evaluated and prolonged reaction lifetimes are observed.

Concepts: Photosynthesis, Oxygen, Carbon dioxide, Aluminium, Oxide, Photosystem, Oxygen evolution, Manganese

28

A periodically aligned Pt nanocup array is employed as a counter electrode in dye-sensitized solar cells (DSSCs). The Pt nanocup array enhances the catalytic area, which results in a greater fill factor (FF) and higher short-circuit current (J(sc) ). A higher density of nanocups is preferable for the performance of DSSCs.

Concepts: Solar cell, Photovoltaics, Electrode, Dye-sensitized solar cell, Platinum, Fill factor