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Over the last decade, interest in 1D charge transport has progressed from the seminal discovery of Landauer quantization of conductance, as a function of carrier density, to finer-scale phenomena at the onset of quantization. This has come to be called the '0.7 anomaly', rather connoting a theoretical mystery of some profundity and universality, which remains open to date. Its somewhat imaginative appellation may tend to mislead, since the anomaly manifests itself over a range of conductance values: anywhere between 0.25–0.95 Landauer quanta. In this paper we offer a critique of the 0.7 anomaly and discuss the extent to which it represents a deep question of physics.

Breast cancer is one of the leading causes of deaths in females worldwide. The high metastatic rate and drug resistance makes it one of the difficult cancers to treat. Early diagnosis and treatment are keys to better survival of breast cancer patients. Conventional treatment approaches like chemotherapy, radiotherapy and surgery suffer from major drawbacks. Novel approaches to improve cancer therapy with minimal damage to normal tissues and better quality of life for cancer patients need to be developed. Among various approaches used for treatment and diagnosis of breast cancer, use of nanoparticles (NPs) is coming up as a new and promising treatment regime. It can help overcome various limitations of conventional therapies like non-targeted effects, resistance to treatment, late diagnosis, etc. Among various nanoparticles studied for their biomedical applications, especially for breast cancer therapy, iron oxide nanoparticles (IONPs) are perhaps the most exciting due to their biocompatibility, biodegradability, size and properties like superparamagnetism. Besides, IONPs are also the only metal oxide nanoparticles approved for clinical use in magnetic resonance imaging (MRI) which is an added advantage for early detection. Therefore in this mini review, we are discussing the developments made in the use of IONPs for breast cancer therapy over the short span of the last five years i.e. 2010−2015. Since late diagnosis and therapy resistance are important drawbacks in breast cancer therapy, the potential of IONPs to overcome these limitations are also evaluated.

This report describes the synthesis of metallic silver nanoparticles (AgNPs) using extracts of four medicinal plants (Aegle marmelos (A. marmelos), Alstonia scholaris (A. scholaris), Andrographis paniculata (A. paniculata) and Centella asiatica (C. asiatica)). The bio-conjugates were characterized by UV–visible spectroscopy, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Fourier transform infrared spectrometry (FTIR), x-ray diffraction (XRD) and zeta potential. This analysis confirmed that UV–Vis spectral peaks at 375 nm, 380 nm, 420 nm and 380 nm are corresponding to A. marmelos, A. scholaris, A. paniculata and C. asiatica mediated AgNPs, respectively. SEM images revealed that all the obtained four AgNPs are predominantly spherical, fibres and rectangle in shape with an average size of 36–97 nm. SEM-EDS and XRD analysis confirmed the presence of elemental AgNPs in crystalline form for all the four nanoparticle samples. The phytochemicals of various medicinal plant extracts with different functional groups were responsible for reduction of Ag⁺ to AgNPs, which act as capping and stabilizing agent. Among four types of AgNPs tested for anticancer activity, the Ap mediated AgNPs had shown enhanced activity against HepG2 cells (27.01 µg ml⁻¹) and PC3 cells (32.15 µg ml⁻¹).

Global palladium nanoparticles of different average diameters in the range 2–19 nm have been synthesized at room temperature by the reduction of K₂PdCl₄ in aqueous alcohols of varying composition in presence of constant proportion of polyvinyl alcohol (PVA). The synthesized nanoparticles have been characterized by different spectroscopic, microscopic and electro analytical techniques like cyclic voltammetry, chronopotentiometry, and chronoamperometry. FTIR spectroscopy detects the effect of co-solvent composition on the particle-PVA interaction involving  −OH group of the latter. X-ray diffraction study shows that the nanoparticles have both face centred cubic and hexagonal crystalline structures which may influence the catalytic capability of the synthesized palladium quantum dots. The study reveals the influence of co-solvent (ethanol) composition in monitoring the average diameter and the nature of encapsulation of palladium nanoparticles which in turn help to monitor the electro-catalytic activity of the synthesized palladium nanoparticles in reference to oxidation of ethanol in alkaline medium.

The reaction-induced deformation and its recovery process in the nanometer scale of a photo-cross-linkable poly(ethyl acrylate) were in situ studied by using Mach–Zehnder interferometry. The ON–OFF modulated irradiation using two different UV wavelengths, 365 nm and 297 nm, was carried out to elucidate the effects of the reversible cross-link on the deformation kinetics of the polymer. It was found that the irradiation time-dependence of the crosslink density generated during the ON–OFF irradiation process deviates from the data obtained by continuous irradiation process, revealing the relaxation effect of the forming poly(ethyl acrylate) networks in the dark during each irradiation cycle. Furthermore, the recovery of the sample thickness can be achieved by photodissociation of the anthracene photodimers by irradiating the cross-linked sample with 297 nm UV light. These experimental results reveal the possibility of reversible control the shrinkage and swelling proceses of a polymeric film by using the photodimerization of anthracene.

The present study reports green synthesis of silver nanoparticles (AgNPs) at room temperature using aqueous Chamaemelum nobile extract for the first time. The effect of silver nitrate concentration, quantity of the plant extract and the reaction time on particle size was optimized and studied by UV–Vis spectroscopy and dynamic light scattering. The appearance of brownish color with λ_max of 422 nm confirmed the formation of AgNPs. Synthesized nanoparticles were further characterized by Fourier transform infrared spectroscopy, x-ray diffraction and transmission electron microscopy. In addition, antimicrobial activity of the AgNPs against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus subtilis was evaluated based on the inhibition zone using the disc-diffusion assay and measurement of minimal inhibition concentration and minimal bactericidal concentration by standard microdilution method. In conclusion, synthesis of nanoparticle with aqueous Chamaemelum nobile extract is simple, rapid, environmentally benign and inexpensive. Moreover, these synthesized nanoparticles exhibit significant antibacterial activity.

Fungi grow especially in dark and moist areas, deteriorating the indoor environment and causing infections that particularly affect immunosuppressed individuals. Antimicrobial coatings have as principal objective to prevent biofilm formation and infections by incorporation of bioactive additives. In this sense, metallic nanoparticles, such as silver, have proven to be active against different microorganisms specially bacteria. Biosynthesized method is a promising environmentally friendly option to obtain nanoparticles. The aim of this research was assess the employment of plants extracts of Aloysia triphylla (cedrón), Laurelia sempervirens (laurel) and Ruta chalepensis (ruda) to obtain silver nanoparticles to be used as an antimicrobial additive to a waterborne coating formulation. The products obtained were assessed against fungal isolates from biodeteriorated indoor coatings. The fungi were identified by conventional and molecular techniques as Chaetomium globosum and Alternaria alternate. The results revealed that the coating with silver nanoparticles obtained with L. sempervirens extract at 60 °C with a size of 9.8 nm was the most efficient against fungal biofilm development.

Array structures of CdS-sensitized ZnO nanorods (NRs) were fabricated on conducting substrates of indium tin oxide (ITO) that serve as working electrodes in photoelectrochemical (PEC) cells for the generation of hydrogen by splitting of water. The ZnO NRs were synthesized by the hydrothermal method at low temperature with different growth times; structures of CdS-sensitized ZnO NRs were created by the dipping method with various dipping times to optimize the efficiency of splitting water. It was found that maximum photoconversion efficiency of an electrode made from CdS-sensitized ZnO NRs with a growth time of 3 h and a dipping time of 30 min under simulated solar irradiation of 100 mW cm⁻² was about 2.7%. The rate of evolution of H₂ gas generated from the water-splitting process was also measured. A maximum rate of 22 ml cm⁻² was achieved after 1 h exposure, which is higher than with CdS–ZnO NR electrodes in previous studies.

Molecular diodes are an interesting topic in the field of single-molecule electronics. Rectification of molecules such as 1,4-aminobenzenethiol (ABT) having different contact areas was reported. However, a more statistical approach is necessary to clarify the rectification of the ABT single-molecule junctions. In this research, we statistically measured the single molecular conductance and I–V characteristics of ABT single-molecule junctions using the scanning tunneling microscope break junction (STM-BJ) method. Two single molecular conductances caused to difference of bridging geometries were observed in the conductance measurements. Statistically significant rectification was not observed for ABT junctions. We concluded rectification does not appear only due to the difference of two anchoring groups in case of a small conjugate molecule such as ABT.

Surface-enhanced Raman scattering (SERS) is a highly sensitive measurement technique that provides Raman peaks at different Raman shift for different molecule structures. The SERS sensor is potentially used to detect food contamination and monitor environmental pollutants. A self-developed SERS system for specific analysis with low development cost is a challenging issue. This study attempts to develop a simple SERS sensor system for detection of bisphenol A (BPA) molecule using SERS substrate of silver nanoplate film. A SERS sensor system was developed, consisting of a light source to excite analyte molecules, Inphotonic Raman probe, sensor chamber and spectrophotometer as an analyser system. A duplex fibre optic is used to transmit light from the source to the probe and from the probe to the spectrophotometer. For SERS measurement, BPA detection was done by comparing the Raman signal spectra of the BPA on the quartz substrate and BPA on the silver nanoplate film. This SERS sensor successfully sensed BPA with SERS enhancement factor (EF) 5.55  ×  10³ and a detection limit of BPA concentration at 1 mM.

The use of virus-like particles (VLPs) as antigens constitutes a well established strategy in preventive vaccination. These non-infective particles have a composition, size, and structure favoring their interaction and processing by the immune system. Recombinant viral nucleocapsids encapsulating bacterial nucleic acids result in potent Th1-driving immunogens. Several antigens have been coadministered with VLPs or conjugated to them to further increase their immunogenicity. In the present work we characterize the size distribution of two different recombinant VLPs obtained as components of HeberNasvac, a novel therapeutic vaccine recently registered to treat chronic hepatitis B. The vaccine ingredients, hepatitis B virus surface and nucleocapsid antigens (HBsAg and HBcAg, respectively) and the vaccine formulation, were evaluated using dynamic light scattering (DLS), transmission electron microscopy (TEM) and light obscuration technology. The results demonstrate that both antigens are nanoparticles with sizes ranging between 20–30 nm, in line with reports in the literature. In addition, DLS studies evidenced the capacity of both antigens to form homologous and heterologous aggregates, both as active ingredients as well as being part of the final product. The evaluation of subvisible particles in HeberNasvac formulation fulfills the requirements in terms of quantity and size established for parenteral pharmaceutical compositions.

Organometallic chemistry plays an increasing role in the synthesis of nanoparticles, as it provides a reliable access to metal nanoparticles with efficient control over their morphology, organization and surface chemistry. In case of magnetic nanoparticles, the synthetic tools provided by organometallic chemistry allow access to nanomaterials of high magnetization, meaning that no dead surface magnetic layer is observed. These objects are thus good candidates to be used as building blocks in composite materials of high added value. This paper reports on the organometallic synthesis of composites made of cobalt nanoparticles and carbon nanotubes. TEM investigations show that attachment of cobalt spheres and rods along the carbon nanotubes is achieved, the rods and tube long axis being aligned parallel to one another.

An efficient protocol for synthesis of silver nanoparticles (AgNPs) using Xanthium strumerium L. leaves was developed. This study revealed that bioactive compounds present in the extract, function as stabilizing and capping agent for AgNPs. SEM, EDX, TEM and XRD studies confirm the structure, crystalline nature and surface morphology of the AgNPs. Size of synthesized AgNPs was in the range of 20–50 nm having spherical morphology. The AgNPs were found to be toxic against pathogenic bacteria such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The use of AgNPs as antibacterial agent is advantageous over other methods for control of pathogenic microorganisms.

Cobalt nanowires with different shape parameters were synthesized via the polyol process. By calculating the magnetic energy product (BH_max) both for dried nano-powder and for nanowires in their synthesis solution, we observed unexpected independent BH_max values from the nanowires shape. A good alignment of the nanowires leads to a higher BH_max value. Our results show that the key parameter driving the magnetic energy product of the cobalt nanowires is the stacking fault density. An exponential collapse of the magnetic energy is observed at very low percentage of structural faults. Cobalt nanowires with almost perfect hcp crystalline structures should present high magnetic energy, which is promising for application in rare earth-free permanent magnets.

Biodistribution studies provide basic information to design and perform various applications of superparamagnetic iron oxide magnetic nanoparticles (SPIOs) in biomedicine such as drug delivery, MRI as well as hyperthermia. Recently, several quantitative measurements as well as new imaging methods have been used to characterize the SPIOs distribution in organs and in tissues of animal model. In this report we used the fabricated iron oxide nanoparticles coated with two block copolymers of polystyrene-co-polyacrylic acid (St-co-PAA) and polylactic acid-co-polyethylene glycol (PLA-PEG). The biodistributions were investigated ex-vivo for several organs of both healthy and Sarcoma transplanted Swiss mice. The SPIOs concentrations were verified mainly by magnetic inductive heating (MIH) measurement with a combination with atomic absorption spectroscopy (AAS). The results indicated the density detected highest in liver and lowest in kidney. The SPIOs concentration increased significantly up to 24 h after the injection. The observations by our two methods not only are in agreement with each other but also consistent with the tendency reported by other techniques. Discussion will also concern injection strategy for various aspects of hyperthermia applications.

In recent years, nanocarriers have emerged as effective platforms for delivering several kinds of herbal medicine and naturally bioactive compounds. In this study we developed an outstanding thermosensitive dendritic nanocarrier to efficiently deliver malloapelta B (Mall B), which is a water insoluble bioactive compound isolated from leaves of Mallotus apelta—Vietnamese medicinal plant. The thermosensitive poly(N-isopropylacrylamide) (PNIPAM) polymer-conjugated polyamidoamine (PAMAM) dendrimer copolymer was prepared via Michael reaction. The copolymer structures were confirmed by proton nuclear magnectic resonance (¹H NMR). Morphology of the nanocarrier was observered around 70–120 nm by transmission electron microscopy (TEM). Size distributions were measured by dynamic light scattering (DLS) of the nanocarrier and its Mall B-loaded performed at 146.8 nm and 194.5 nm, respectively. The PNIPAM-g-PAMAM-based nanocarrier exhibited higher Mall B loading efficiency (DL  =  59.93  ±  0.19%) and entrapment efficiency (EE  =  89.98  ±  2.06%) as compared to PNIPAM (DL  =  52.54  ±  0.45% and EE  =  66.45  ±  2.78%). In vitro release indicated that approximately 30% amount of the loaded Mall B released at pH 5.5 after 54 h tracking. At the same time, 12.5% amount of the molecules released at pH 7.4.Cytotoxicity assay results showed that the Mall B-loaded nanocarrier significantly inhibited HepG2 cancer cell proliferation. These obtained results indicated that the nanocarrier could solve hydrophobic property of Mall B for further medicine applications.

Creatinine is one of the most commonly used bio markers of renal function. This paper reports a study on detection of creatinine using silver–platinum (AgPt) nanoferns substrates to fabricate a surface-enhanced Raman spectroscopy (SERS) sensor. The AgPt nanoferns were synthesized by liquid phase deposition (LPD) where the morphology structures and thickness of the AgPt nanoferns were controlled by varying the concentration of formic acid which was acting as the reducing agent. We have obtained four different nanoferns structures and thicknesses. This study showed that the AgPt nanoferns structure synthesized with 40 mM formic acid give the highest Raman peak intensity for a 0.05 M creatinine sample.

We present the temperature and magnetic-field dependence of electrical resistivity (ρ(T, B) dependence) in the milikelvin range for U-Pt alloys with Pt concentration in the range of 0–15 atomic percent (at.%) prepared by splat-cooling technique. The high-temperature cubic γ-U phase can be stabilized down to room temperature in the samples with 15 at.% Pt. All samples exhibit superconducting transitions below 1.1 K revealed by abrupt resistivity drops with transition widths of several tens of milikelvins in zero magnetic field. The H–T diagrams for all investigated alloys are in good agreement with the Ginzburg-Landau approximation. The U-Pt alloys with cubic γ-U phase are very stable in air and hydrogen exposure at atmospheric conditions. They can absorb a large amount of hydrogen upon applying hydrogen pressure  >2.5 bars and easily release it by heating in vacuum, showing the possibility of using U-Pt-based hydrides as a medium for hydrogen storage.

A novel magnetically recoverable hematite nanoparticles (α-Fe₂O₃ NPs) was fabricated by a simple, one pot, and green method using the rhizome of Cyperus rotundus L., as a reducing and stabilizing agent. The prepared nanoparticles were well characterized by all parameters. TEM showed that the hematite nanoparticles had a rhombohedral shape and ranged in size from 80 to 100 nm. The phase study of the α-Fe₂O₃ nanoparticles was confirmed by Raman spectroscopy. In addition, the synthesized nanoparticles shows good photocatalytic activity in degradation of highly toxic Congo red dye within 25 min, and the same NPs exhibits higher catalytic activity for the reduction of 4-nitro-o-phenylenediamine (4-NPD) to 1,2,4-benzenetriamine in the presence of NaBH₄ within 12 min. After the reaction, the catalyst was recovered and reused three times without significant loss of catalytic activity.

PANI/MWCNT-ZnS nanocomposites with different contents of ZnS wt.% have been synthesized by the chemical oxidative in situ polymerization reaction of aniline in the presence of multi-walled carbon nanotube (MWCNT). TEM, XRD, RAMAN and TGA studies have been done for the structural and thermal characterizations of the samples. The particle sizes of ZnS nanoparticles have the values in the range from 3.21 to 5.08 nm. XRD spectrum reveals the co-existence of MWCNT, ZnS in PANI matrix, where ZnS forms a hexagonal structure. TGA result shows that nanocomposite becomes more thermally stable with increase in ZnS content. The dc electrical transport property of PANI/MWCNT-ZnS nanocomposites has been investigated within a temperature range 77 K  ⩽  T  ⩽  300 K. The dc conductivity follows a 3D variable range hopping (VRH) model. A large magnetoconductivity change (23.1%) is observed for 2 wt.% ZnS content in PANI/MWCNT-ZnS, which is explained by the wave function shrinkage model.