Edible additive effects on zebrafish cardiovascular functionality with hydrodynamic assessment.

Food coloring is often used as a coloring agent in foods, medicines and cosmetics, and it was reported to have certain carcinogenic and mutagenic effects in living organisms. Investigation of physiological parameters using zebrafish is a promising methodology to understand disease biology and drug toxicity for various drug discovery on humans. Zebrafish (Danio rerio) is a well-acknowledged model organism with combining assets such as body transparency, small size, low cost of cultivation, and high genetic homology with humans and is used as a specimen tool for the in-vivo throughput screening approach. In addition, recent advances in microfluidics show a promising alternative for zebrafish manipulation in terms of drug administration and extensive imaging capability. This pilot work highlighted the design and development of a microfluidic detection platform for zebrafish larvae through investigating the effects of food coloring on cardiovascular functionality and pectoral fin swing ability. The zebrafish embryos were exposed to the Cochineal Red and Brilliant Blue FCF pigment solution in a concentration of (0.02‰, 0.2‰) cultured in the laboratory from the embryo stage to hatching and development until 9 days post fertilization (d.p.f.). In addition, zebrafish swimming behaviors in terms of pectoral fin beating towards the toxicity screening were further studied by visualizing the induced flow field. It was evidenced that Cochineal Red pigment at a concentration of 0.2‰ not only significantly affected the zebrafish pectoral fin swing behavior, but also significantly increased the heart rate of juvenile fish. The higher concentration of Brilliant Blue FCF pigment (0.2%) increased heart rate during early embryonic stages of zebrafish. However, zebrafish exposed to food coloring did not show any significant changes in cardiac output. The applications of this proposed platform can be further extended towards observing the neurobiological/hydrodynamic behaviors of zebrafish larvae for practical applications in drug tests.

Electrodes with Electrodeposited Water-excluding Polymer Coating Enable High-Voltage Aqueous Supercapacitors.

Aqueous supercapacitors are powerful energy sources, but they are limited by energy density that is much lower than lithium-ion batteries. Since raising the voltage beyond the thermodynamic potential for water splitting (1.23 V) can boost the energy density, there has been much effort on water-stabilizing salvation additives such as Li2SO4 that can provide an aqueous electrolyte capable of withstanding ~1.8 V. Guided by the first-principles calculations that reveal water can promote hydrogen and oxygen evolution reactions, here, we pursue a new strategy of covering the electrode with a dense electroplated polymerized polyacrylic acid, which is an electron insulator but a proton conductor and proton reservoir. The combined effect of salvation and coating expands the electrochemical window throughout pH 3 to pH 10 to 2.4 V for both fast and slow proton-mediated redox reactions. This allows activated carbon to quadruple the energy density, a kilogram of nitrogen-doped graphene to provide 127 Watt-hour, and both to have improved endurance because of suppression of water-mediated corrosion. Therefore, aqueous supercapacitors can now achieve energy densities quite comparable to that of a lithium-ion battery, but at 100 times the charging/discharging speed and cycle durability.

Orthorhombic Nb2O5-x for Durable High-Rate Anode of Li-Ion Batteries.

Li4Ti5O12 anode can operate at extraordinarily high rates and for a very long time, but it suffers from a relatively low capacity. This has motivated much research on Nb2O5 as an alternative. In this work, we present a scalable chemical processing strategy that maintains the size and morphology of nano-crystal precursor but systematically reconstitutes the unit cell composition, to build defect-rich porous orthorhombic Nb2O5-x with a high-rate capacity many times those of commercial anodes. The procedure includes etching, proton ion exchange, calcination, and reduction, and the resulting Nb2O5-x has a capacity of 253 mA h g-1 at 0.5C, 187 mA h g-1 at 25C, and 130 mA h g-1 at 100C, with 93.3% of the 25C capacity remaining after cycling for 4,000 times. These values are much higher than those reported for Nb2O5 and Li4Ti5O12, thanks to more available surface/sub-surface reaction sites and significantly improved fast ion and electron conductivity.

Biomimetic nano-surfactant stabilizes sub-50 nanometer phospholipid particles enabling high paclitaxel payload and deep tumor penetration.

Sub-50 nm nanoparticles feature long circulation and deep tumor penetration. However, at high volume fractions needed for intravenous injection, safe, highly biocompatible phospholipids cannot form such nanoparticles due to the fluidity of phospholipid shells. Here we overcome this challenge using a nano-surfactant, a sterilized 18-amino-acid biomimetic of the amphipathic helical motif abundant in HDL-apolipoproteins. As it induces a nanoscale phase (glass) transition in the phospholipid monolayer, the peptide stabilizes 5-7 nm phospholipid micelles that do not fuse at high concentrations but aggregate into stable micellesomes exhibiting size-dependent penetration into tumors. In mice bearing human Her-2-positive breast cancer xenografts, high-payload paclitaxel encapsulated in 25 nm (diameter) micellesomes kills more cancer cells than paclitaxel in standard clinical formulation, as evidenced by the enhanced apparent diffusion coefficient of water determined by in vivo MR imaging. Importantly, the bio-inertness of this biomimetic nano-surfactant spares the nanoparticles from being absorbed by liver hepatocytes, making them more generally available for drug delivery.

Scalability of voltage-controlled filamentary and nanometallic resistance memory devices.

Much effort has been devoted to device and materials engineering to realize nanoscale resistance random access memory (RRAM) for practical applications, but a rational physical basis to be relied on to design scalable devices spanning many length scales is still lacking. In particular, there is no clear criterion for switching control in those RRAM devices in which resistance changes are limited to localized nanoscale filaments that experience concentrated heat, electric current and field. Here, we demonstrate voltage-controlled resistance switching, always at a constant characteristic critical voltage, for macro and nanodevices in both filamentary RRAM and nanometallic RRAM, and the latter switches uniformly and does not require a forming process. As a result, area-scalability can be achieved under a device-area-proportional current compliance for the low resistance state of the filamentary RRAM, and for both the low and high resistance states of the nanometallic RRAM. This finding will help design area-scalable RRAM at the nanoscale. It also establishes an analogy between RRAM and synapses, in which signal transmission is also voltage-controlled.

A Robust and Conductive Black Tin Oxide Nanostructure Makes Efficient Lithium-Ion Batteries Possible.

SnO2 -based lithium-ion batteries have low cost and high energy density, but their capacity fades rapidly during lithiation/delithiation due to phase aggregation and cracking. These problems can be mitigated by using highly conducting black SnO2-x , which homogenizes the redox reactions and stabilizes fine, fracture-resistant Sn precipitates in the Li2 O matrix. Such fine Sn precipitates and their ample contact with Li2 O proliferate the reversible Sn → Li x Sn → Sn → SnO2 /SnO2-x cycle during charging/discharging. SnO2-x electrode has a reversible capacity of 1340 mAh g-1 and retains 590 mAh g-1 after 100 cycles. The addition of highly conductive, well-dispersed reduced graphene oxide further stabilizes and improves its performance, allowing 950 mAh g-1 remaining after 100 cycles at 0.2 A g-1 with 700 mAh g-1 at 2.0 A g-1 . Conductivity-directed microstructure development may offer a new approach to form advanced electrodes.

Distinguishing uniform switching from filamentary switching in resistance memory using a fracture test.

Resistance random access memory (RRAM) is a rapidly developing emergent nanotechnology. For practical applications and basic understanding, it is important to ascertain whether RRAM undergoes uniform or filamentary switching, but on this point previous area-scaling studies have often shown ambiguous and conflicting findings. Here we demonstrate a simple test-physically breaking the device into two and studying their characteristics individually-can make a definitive determination. Our experiment on two prototypical RRAMs found that one (the nanometallic memory) switches and conducts uniformly while the other (the filamentary memory) does not. It also probes the statistics of nanofilaments: the resistance statistics of the filamentary memory reveals for the first time a large population of partially developed filaments in addition to the filament that dominates switching. Remarkably, the filamentary memory can also be stress-switched to a lower resistance state during fracture, which is reminiscent of stress-switching of the nanometallic memory and may be taken as direct evidence of electron-phonon interaction in the filaments.

The link between chronic rhinosinusitis and asthma: A questionnaire-based study.

Treatments for chronic rhinosinusitis (CRS) and asthma can affect both conditions, based on the united airway concept. This study aimed to evaluate the link between CRS and asthma, based on disease-specific quality of life measures.We performed a prospective cohort study to investigate the correlations between results from CRS- and asthma-specific questionnaires. Thirty-two patients with asthma and CRS were evaluated before and after undergoing nasal surgery at a tertiary medical center.There were significant correlations between the results from the Asthma Control Test (ACT) and the Sino-Nasal Outcome Test-22, as well as between the results of the ACT and Rhinoconjunctivitis Quality of Life Questionnaire, at both the preoperative and 3-month postoperative evaluations (P < 0.01). Moreover, nasal surgery improved the sinonasal symptoms, asthma control, and pulmonary function (P < 0.01).Increasingly severe sinonasal symptoms of CRS were associated with poor asthma control. Therefore, CRS and asthma should be considered and treated as common airway diseases.

Biodegradable resistive switching memory based on magnesium difluoride.

This study presents a new type of resistive switching memory device that can be used in biodegradable electronic applications. The biodegradable device features magnesium difluoride as the active layer and iron and magnesium as the corresponding electrodes. This is the first report on magnesium difluoride as a resistive switching layer. With on-off ratios larger than one hundred, the device on silicon switches at voltages less than one volt and requires only sub-mA programming current. AC endurance of 10(3) cycles is demonstrated with ±1 V voltage pulses. The switching mechanism is attributed to the formation and rupture of conductive filaments comprising fluoride vacancies in magnesium difluoride. Devices fabricated on a flexible polyethylene terephthalate substrate are tested for functionality, and degradation is subsequently demonstrated in de-ionized water. An additional layer of magnesium difluoride is used to hinder the degradation and extend the lifetime of the device.

Observing Oxygen Vacancy Driven Electroforming in Pt-TiO2-Pt Device via Strong Metal Support Interaction.

Oxygen vacancy formation, migration, and subsequent agglomeration into conductive filaments in transition metal oxides under applied electric field is widely believed to be responsible for electroforming in resistive memory devices, although direct evidence of such a pathway is lacking. Here, by utilizing strong metal-support interaction (SMSI) between Pt and TiO2, we observe via transmission electron microscopy the electroforming event in lateral Pt/TiO2/Pt devices where the atomic Pt from the electrode itself acts as a tracer for the propagating oxygen vacancy front. SMSI, which originates from the d-orbital overlap between Pt atom and the reduced cation of the insulating oxide in the vicinity of oxygen vacancies, was optimized by fabricating nanoscale devices causing Pt atom migration tracking the moving oxygen vacancy front from the anode to cathode during electroforming. Experiments performed in different oxidizing and reducing conditions, which tune SMSI in the Pt-TiO2 system, further confirmed the role of oxygen vacancies during electroforming. These observations also demonstrate that the noble metal electrode may not be as inert as previously assumed.

Nitrogen-doped mesoporous carbon of extraordinary capacitance for electrochemical energy storage.

Carbon-based supercapacitors can provide high electrical power, but they do not have sufficient energy density to directly compete with batteries. We found that a nitrogen-doped ordered mesoporous few-layer carbon has a capacitance of 855 farads per gram in aqueous electrolytes and can be bipolarly charged or discharged at a fast, carbon-like speed. The improvement mostly stems from robust redox reactions at nitrogen-associated defects that transform inert graphene-like layered carbon into an electrochemically active substance without affecting its electric conductivity. These bipolar aqueous-electrolyte electrochemical cells offer power densities and lifetimes similar to those of carbon-based supercapacitors and can store a specific energy of 41 watt-hours per kilogram (19.5 watt-hours per liter).

A new tubular graphene form of a tetrahedrally connected cellular structure.

3D architectures constructed from a tubular graphene network can withstand repeated >95% compression cycling without damage. Aided by intertubular covalent bonding, this material takes full advantage of the graphene tube's unique attributes, including complete pre- and post-buckling elasticity, outstanding electrical conductivity, and extraordinary physicochemical stability. A highly connected tubular graphene will thus be the ultimate, structurally robust, ultrastrong, ultralight material.

A study of the relationship of metabolic MR parameters to estrogen dependence in breast cancer xenografts.

(1)H MRS, (31)P MRS and diffusion-weighted MRI (DW-MRI) were applied to study the metabolic changes associated with estrogen dependence in estrogen receptor (ER)-positive BT-474 and triple-negative HCC1806 breast cancer xenografts supplemented with or without 17ß-estradiol (E2) at a dose of 0.18 or 0.72 mg/pellet. Furthermore, the effect of estrogen withdrawal on the metabolism of BT-474 and HCC1806 breast cancer xenografts was studied on day 0, day 2 and day 10. Increasing the dose of E2 resulted in a rapid growth and increases in the lactate level and phosphomonoester/ß-nucleoside triphosphate (PME/ßNTP), phosphocreatine/inorganic phosphate (PCr/Pi) and ßNTP/Pi ratios in BT-474 breast cancer xenografts; however, no significant changes were found in HCC1806 breast cancer xenografts. Estrogen withdrawal resulted in a marked decrease in lactate level and PME/ßNTP ratio and an observed increase in ßNTP/Pi, PCr/Pi and apparent diffusion coefficient (ADC) values of BT-474 breast cancer xenografts on day 10. These data suggest that the lactate level and PME/ßNTP, PCr/Pi and ßNTP/Pi ratios of ER-positive tumors are closely related to ER dependence.

Nanofilament Dynamics in Resistance Memory: Model and Validation.

Filamentary resistive random-access memory (ReRAM) employs a single nanoscale event to trigger a macroscopic state change. While fundamentally it involves a gradual electrochemical evolution in a nanoscale filament that culminates in an abrupt change in filament's resistance, understanding over many length and time scales from the filament level to the device level is needed to inform the device behavior. Here, we demonstrate the nanoscale elements have corresponding elements in an empirical equivalent circuit. Specifically, the filament contains a variable resistor and capacitor that switch at a critical voltage. This simple model explains several observations widely reported on disparate filamentary ReRAMs. In particular, its collective system dynamics incorporating the power-law time-relaxation of the variable capacitance can accurately account for the responses of variously sized single-filament HfOx ReRAMs to DC/quasi-static and pulse electrical stimulation, exhibiting Avrami-like switching kinetics and a pulse-rate dependence in on/off voltages.

Resolving voltage-time dilemma using an atomic-scale lever of subpicosecond electron-phonon interaction.

Nanoelectronic memory based on trapped charge need to be small and fast, but fundamentally it faces a voltage-time dilemma because the requirement of a high-energy barrier for data retention under zero/low electrical stimuli is incompatible with the demand of a low-energy barrier for fast switching under a modest programming voltage. One solution is to embed an atomic-level lever of localized electron-phonon interaction to autonomously reconfigure trap-site's barrier in accordance to the electron-occupancy of the site. Here we demonstrate an atomically levered resistance-switching memory built on locally flexible amorphous nanometallic thin films: charge detrapping can be triggered by a mechanical force, the fastest one being a plasmonic Lorentz force induced by a nearby electron or positron bunch passing in 10(-13) s. The observation provided the first real-time evidence of an electron-phonon interaction in action, which enables nanometallic memory to turn on at a subpicosecond speed yet retain long-term memory, thus suitable for universal memory and other nanoelectron applications.

Quantitative evaluation of the reticuloendothelial system function with dynamic MRI.

PURPOSE: To evaluate the reticuloendothelial system (RES) function by real-time imaging blood clearance as well as hepatic uptake of superparamagnetic iron oxide nanoparticle (SPIO) using dynamic magnetic resonance imaging (MRI) with two-compartment pharmacokinetic modeling. MATERIALS AND METHODS: Kinetics of blood clearance and hepatic accumulation were recorded in young adult male 01b74 athymic nude mice by dynamic T2* weighted MRI after the injection of different doses of SPIO nanoparticles (0.5, 3 or 10 mg Fe/kg). Association parameter, Kin, dissociation parameter, Kout, and elimination constant, Ke, derived from dynamic data with two-compartment model, were used to describe active binding to Kupffer cells and extrahepatic clearance. The clodrosome and liposome were utilized to deplete macrophages and block the RES function to evaluate the capability of the kinetic parameters for investigation of macrophage function and density. RESULTS: The two-compartment model provided a good description for all data and showed a low sum squared residual for all mice (0.27±0.03). A lower Kin, a lower Kout and a lower Ke were found after clodrosome treatment, whereas a lower Kin, a higher Kout and a lower Ke were observed after liposome treatment in comparison to saline treatment (P<0.005). CONCLUSION: Dynamic SPIO-enhanced MR imaging with two-compartment modeling can provide information on RES function on both a cell number and receptor function level.

Cause and prevention of moisture-induced degradation of resistance random access memory nanodevices.

Dielectric thin films in nanodevices may absorb moisture, leading to physical changes and property/performance degradation, such as altered data storage and readout in resistance random access memory. Here we demonstrate using a nanometallic memory that such degradation proceeds via nanoporosity, which facilitates water wetting in otherwise nonwetting dielectrics. Electric degradation only occurs when the device is in the charge-storage state, which provides a nanoscale dielectrophoretic force directing H2O to internal field centers (sites of trapped charge) to enable bond rupture and charged hydroxyl formation. While these processes are dramatically enhanced by an external DC or AC field and electron-donating electrodes, they can be completely prevented by eliminating nanoporosity, depositing a barrier layer, or using an oxidation-resistant electrode. These findings provide insight for understanding high-performance memory and field-assisted degradation of nanodevices.

Dynamic-load-enabled ultra-low power multiple-state RRAM devices.

Bipolar resistance-switching materials allowing intermediate states of wide-varying resistance values hold the potential of drastically reduced power for non-volatile memory. To exploit this potential, we have introduced into a nanometallic resistance-random-access-memory (RRAM) device an asymmetric dynamic load, which can reliably lower switching power by orders of magnitude. The dynamic load is highly resistive during on-switching allowing access to the highly resistive intermediate states; during off-switching the load vanishes to enable switching at low voltage. This approach is entirely scalable and applicable to other bipolar RRAM with intermediate states. The projected power is 12 nW for a 100 × 100 nm(2) device and 500 pW for a 10 × 10 nm(2) device. The dynamic range of the load can be increased to allow power to be further decreased by taking advantage of the exponential decay of wave-function in a newly discovered nanometallic random material, reaching possibly 1 pW for a 10×10 nm(2) nanometallic RRAM device.

Core-shell nanocapsules stabilized by single-component polymer and nanoparticles for magneto-chemotherapy/hyperthermia with multiple drugs.

Iron-oxide-containing double emulsion capsules carrying both hydrophilic and hydrophobic therapeutic molecules can deliver drugs and energy on demand in vivo. Magneto-chemotherapy/hyperthermia involves a burst-like release of hydrophilic doxorubicin and hydrophobic paclitaxel, remotely triggered by a high frequency magnetic field, which also releases energy via internalized iron oxide nanoparticles, all contributing to cell kill.

Quantum-dot-tagged reduced graphene oxide nanocomposites for bright fluorescence bioimaging and photothermal therapy monitored in situ.

Quantum-dot-tagged reduced graphene oxide (QD-rGO) nanocomposites (left) internalized into targeted tumor cells display bright fluorescence from the QDs (right); by absorbing NIR radiation incident on the rGO and converting it into heat, they also cause simultaneous cell death and fluorescence reduction (bottom). The nanocomposite is thus capable of tumor imaging, photothermal therapy and in situ monitoring of treatment in progress.