Publisher Correction: Recent progress and perspectives of space electric propulsion systems based on smart nanomaterials.

The original PDF version of this Article had an incorrect volume number of '8'; it should have been '9'. This has been corrected in the PDF version of the Article. The HTML version was correct from the time of publication.

Recent progress and perspectives of space electric propulsion systems based on smart nanomaterials.

Drastic miniaturization of electronics and ingression of next-generation nanomaterials into space technology have provoked a renaissance in interplanetary flights and near-Earth space exploration using small unmanned satellites and systems. As the next stage, the NASA's 2015 Nanotechnology Roadmap initiative called for new design paradigms that integrate nanotechnology and conceptually new materials to build advanced, deep-space-capable, adaptive spacecraft. This review examines the cutting edge and discusses the opportunities for integration of nanomaterials into the most advanced types of electric propulsion devices that take advantage of their unique features and boost their efficiency and service life. Finally, we propose a concept of an adaptive thruster.

Energy band diagram of device-grade silicon nanocrystals.

Device grade silicon nanocrystals (NCs) are synthesized using an atmospheric-pressure plasma technique. The Si NCs have a small and well defined size of about 2.3 nm. The synthesis system allows for the direct creation of thin films, enabling a range of measurements to be performed and easy implementation of this material in different devices. The chemical stability of the Si NCs is evaluated, showing relatively long-term durability thanks to hydrogen surface terminations. Optical and electrical characterization techniques, including Kelvin probe, ultraviolet photoemission spectroscopy and Mott-Schottky analysis, are employed to determine the energy band diagram of the Si NCs.

Synthesis of nanocrystals by discharges in liquid nitrogen from Si-Sn sintered electrode.

The synthesis feasibility of silicon-tin nanocrystals by discharges in liquid nitrogen is studied using a Si-10 at % Sn sintered electrode. Time-resolved optical emission spectroscopy shows that silicon and tin melt almost simultaneously. The presence of both vapours does not lead to the synthesis of alloyed nanocrystals but to the synthesis of separate nanocrystals of silicon and tin with average sizes of 10 nm. These nanocrystals are transformed into amorphous silicon oxide (am-SiO2) and ß-SnO2 by air oxidation, after evaporation of the liquid nitrogen. The synthesis of an am-Si0.95Sn0.05 phase around large silicon crystals (~500 nm) decorated by ß-Sn spheroids is achieved if the current flowing through electrodes is high enough. When the sintered electrode is hit by powerful discharges, some grains are heated and tin diffuses in the large silicon crystals. Next, these grains are shelled and fall into the dielectric liquid.

Hybrid Carbon-Based Nanostructured Platforms for the Advanced Bioreactors.

Mankind faces several global challenges such as chronic and acute hunger, global poverty, energy deficiency and environment conservation. Common biotechnologies based on batch, fluidbed and other similar processes are now extensively used for the production of a wide range of products such as antibiotics, biofuels, cultured and fermented food products. Unfortunately, these processes suffer from low efficiency, high energy demand, low controllability and rapid biocatalyst degradation by microbiological attack, and thus still are not capable of seriously addressing the global hunger and energy deficiency challenges. Moreover, sustainable future technologies require minimizing the environmental impact of toxic by-products by implementing the "life produces organic matter, organic matter sustains life" principle. Nanostructure-based biotechnology is one of the most promising approaches that can help to solve these challenges. In this work we briefly review the unique features of the carbon-based nanostructured platforms, with some attention paid to other nanomaterials. We discuss the main building blocks and processes to design and fabricate novel platforms, with a focus on dense arrays of the vertically-aligned nanostructures, mainly carbon nanotubes and graphene. Advantages and disadvantages of these systems are considered.

A silicon nanocrystal/polymer nanocomposite as a down-conversion layer in organic and hybrid solar cells.

Silicon nanocrystal (Si-nc) down-conversion is demonstrated to enhance organic and hybrid organic/inorganic bulk heterojunction solar cells based on PTB7:[70]PCBM bulk heterojunction devices. Surfactant free surface-engineered Si-ncs can be integrated into the device architecture to be optically active and provide a means of effective down-conversion of blue photons (high energy photons below ∼450 nm) into red photons (above ∼680 nm) leading to 24% enhancement of the photocurrent under concentrated sunlight. We also demonstrate that the down-conversion effect under 1-sun is enhanced in the case of hybrid solar cells where engineered Si-ncs are also included in the active layer.

Osmophobia in allodynic migraineurs: cause or consequence of central sensitization?

Migraine is a primary headache characterized by recurrent attacks of head pain associated with nausea or vomit, photophobia, phonophobia and osmophobia. The presence of osmophobia during migraine attacks seems to be a very specific complaint. Cutaneous allodynia (CA) is very common in migraineurs, and it is the most evident clinical manifestation of central sensitization, a mechanism involved in migraine chronification. This study was aimed at identifying the possible correlation between osmophobia and CA in migraineurs. 673 migraineurs were studied (492 episodic, 181 chronic). The prevalence of both CA and osmophobia was higher in chronic than in episodic migraineurs. The association between these two symptoms was significant in chronic migraineurs at Chi square test. The highlighted relationship between CA and osmophobia may be interpreted in different ways: central sensitization induced by recurrent pain stimulation may in parallel induce a distortion of both cutaneous sensitivity (CA) and olfaction (osmophobia); alternatively, the recurrent olfactory stimulation in subjects with a hypersensitivity to olfactory stimuli may co-work with repetitive pain stimulation to induce the central sensitization process.

Negative emotions in migraineurs dreams: the increased prevalence of oneiric fear and anguish, unrelated to mood disorders.

BACKGROUND: Migraineurs brain has shown some functional peculiarities that reflect not only in phonophobia, and photophobia, but also in mood and sleep. Dreaming is a universal mental state characterized by hallucinatory features in which imagery, emotion, motor skills, and memory are created de novo. We evaluated dream contents and associated emotions in migraineurs. MATERIALS AND METHODS: 412 subjects: 219 controls; and 148 migraineurs (66 with aura, MA; 82 without aura, MO), and 45 tension type headache patients (TTH). A semistructured retrospective self-reported questionnaire was used to evaluate dreams. The Generalized Anxiety Disorder Questionnaire (GAD-7), and the Patient Health Questionnaire (PHQ-9) were administered to evaluate anxiety and depression. RESULTS: Migraineurs showed increased levels of anxiety (P = 0.0002 for MA versus controls, P = 0.004 for MO versus controls). Fear and anguish during dreaming were more frequently reported by migraine patients compared to controls, independently by anxiety and depression scores. DISCUSSION: The brain of migraineurs seems to dream with some peculiar features, all with a negative connotation, as fear and anguish. It may be due to the recorded negative sensations induced by recurrent migraine pain, but it may just reflect a peculiar attitude of the mesolimbic structures of migraineurs brain, activated in both dreaming and migraine attacks.

Semiconducting quantum confined silicon-tin alloyed nanocrystals prepared by ns pulsed laser ablation in water.

Here we demonstrate the material's synthetic feasibility for semiconducting alloyed silicon-tin nanocrystals (SiSn-NCs) with quantum confinement effects. An environmentally friendly synthesis is achieved by ns laser ablation of amorphous SiSn in water at ambient conditions. Plasmas generated in the liquid by laser pulses are characterized by spatial confinement with very high pressure (GPa), which allowed the growth of the SiSn-NCs via kinetic pathways. We further illustrate that surface engineering by a direct-current atmospheric pressure microplasma is capable of tailoring the SiSn-NCs surface properties without the need for lengthy surfactants, resulting in room temperature photoluminescence (PL); the PL peak wavelength is red-shifted by more than 250 nm with respect to the PL peak wavelengths observed for comparable elemental silicon nanocrystals.

Synthesis of surfactant-free electrostatically stabilized gold nanoparticles by plasma-induced liquid chemistry.

Plasma-induced non-equilibrium liquid chemistry is used to synthesize gold nanoparticles (AuNPs) without using any reducing or capping agents. The morphology and optical properties of the synthesized AuNPs are characterized by transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy. Plasma processing parameters affect the particle shape and size and the rate of the AuNP synthesis process. Particles of different shapes (e.g. spherical, triangular, hexagonal, pentagonal, etc) are synthesized in aqueous solutions. In particular, the size of the AuNPs can be tuned from 5 nm to several hundred nanometres by varying the initial gold precursor (HAuCl4) concentration from 2.5 µM to 1 mM. In order to reveal details of the basic plasma-liquid interactions that lead to AuNP synthesis, we have measured the solution pH, conductivity and hydrogen peroxide (H2O2) concentration of the liquid after plasma processing, and conclude that H2O2 plays the role of the reducing agent which converts Au(+3) ions to Au(0) atoms, leading to nucleation growth of the AuNPs.

Experimental study of a planar atmospheric-pressure plasma operating in the microplasma regime.

Electrical characterization of a nonthermal radio-frequency atmospheric-pressure microplasma in a parallel plate configuration has shown that reducing electrode gap into the submillimeter range increases current and power density at a reduced voltage as compared to similar plasmas at larger electrode gaps which have no gap dependence. Calculation of sheath thickness and electric fields in the sheath and in the bulk demonstrate a dependence on the electrode gap as it is reduced into the submillimeter regime, indicating a distinct regime of operation.

Molecular cloning, characterisation and expression of a manganese superoxide dismutase gene from peach (Prunus persica [L.] Batsch).

Two cDNA clones encoding mitochondrial manganese superoxide dismutases (MnSODs) from peach ( Prunus persica [L.] Batsch) were identified, which show homologies to several plant MnSODs. The amino acid sequence predicted from one full-length clone ( MnSOD1) showed the highest homology to an MnSOD from Nicotiana plumbaginifolia (94%) and included a 24-amino acid transit peptide typical of those used to target proteins to the mitochondria. A second, partial clone ( MnSOD2) showed divergence from MnSOD1 in the 3' untranslated region. It could therefore derive from a second gene or from an allele of MnSOD1. Southern hybridisation analysis suggests the existence of two MnSOD genes in peach. SOD isoenzyme profiles, MnSOD1 expression and protein levels were studied in aerial vegetative tissues derived from plants of different ages and in adult plants during the seasonal cycle. Zymograms revealed at least two isoforms of MnSODs in pre-shooting vegetative buds and in developing fruits. Levels of MnSODs were lower in leaves derived from apical shoots of adult plants than in leaves derived from seedlings, basal shoots or in vitro propagated juvenile plants, which are considered as juvenile-like structures. The MnSOD1 transcript and protein followed the same pattern. The results suggest that the steady-state levels of MnSOD1 mRNA in leaves vary with both the ontogenetic stage and the growth rate of the tissues examined.

Overexpression of KNAT1 in lettuce shifts leaf determinate growth to a shoot-like indeterminate growth associated with an accumulation of isopentenyl-type cytokinins.

Leaves are specialized organs characterized by defined developmental destiny and determinate growth. The overexpression of Knotted1-like homeobox genes in different species has been shown to alter leaf shape and development, but a definite role for this class of genes remains to be established. Transgenics that overexpress Knotted1-like genes present some traits that are characteristic of altered cytokinin physiology. Here we show that lettuce (Lactuca sativa) leaves that overexpress KNAT1, an Arabidopsis kn1-like gene, acquire characteristics of indeterminate growth typical of the shoot and that this cell fate change is associated with the accumulation of specific types of cytokinins. The possibility that the phenotypic effects of KNAT1 overexpression may arise primarily from the modulation of local ratios of different cytokinins is discussed.

Isolation and molecular characterisation of the gene encoding the cytoplasmic ribosomal protein S28 in Prunus persica [L.]] Batsch.

RT-PCR was performed on peach (Prunus persica [L.] Batsch) RNA to isolate cDNAs corresponding to transcripts which are differentially expressed in leaves borne on basal and apical shoots. A gene was identified which was more highly expressed in the leaves of basal shoots, and codes for the cytoplasmic protein S28 present in the small ribosomal subunit. The 5' leader regions of RPS28 mRNAs were found to harbour 8-11 pyrimidine tracts, which suggested similarities to regulatory stretches that control the translation of mRNAs for ribosomal proteins in animals. The peach S28 is encoded by two intron-containing genes, which are both transcribed in mitotically active tissues such as developing leaves and roots. In situ hybridisation to shoot vegetative apices and the measurement of nucleus/nucleolus ratios indicated that RPS28 expression was confined to areas undergoing active cell division. The mature RPS28 mRNA was detected as a single species in actively dividing tissues such as apical tips, developing leaves, vegetative buds, stamens, developing fruits and roots. In contrast, accumulation of a precursor RNA, in the presence of the mature product, was found in fully expanded leaves and subtending stems, while only the precursor species was detected in several late-stage tissues. This phenomenon suggested that expression of the mature RNA is controlled at the level of splicing and turnover of the precursor RNA. This is similar to the mode of regulation of ribosomal protein genes in animals.

MsJ1, an alfalfa DnaJ-like gene, is tissue-specific and transcriptionally regulated during cell cycle.

DnaJ-like proteins are molecular chaperones that regulate Hsp70 ATPase activity both in protein folding, assembly and disassembly of protein complexes. Here we report the isolation of MsJ1, an alfalfa gene encoding a protein homologous to cytosolic DnaJ-like proteins. MsJ1 was induced under heat-shock treatment in both leaves and stems of adult plants. In the absence of heat shock MsJ1 expression was tissue-specific with the highest levels of mRNA in roots and in embryonal structures. High levels of transcript were also detected in cotyledons where active degradation of storage protein occurs. In synchronized alfalfa suspension-cultured cells the MsJ1 transcript was actively expressed and showed a phase-specific modulation during cell cycle with a 2-fold induction in G2/M. These findings suggest that DnaJ-like proteins play an active role in regulating normal cellular events like protein degradation, morphogenesis and cell cycle progression.

[Painful muscle spasms of the trunk and upper limbs: tetanus or latrodectism? A case report]. / Spasmi dolorosi della muscolatura del tronco e degli arti superiori: tetano o latrodectismo? Presentazione di un caso clinico.

A clinical case of a young adult 23-years old is reported. The concomitant presence of tetanic symptoms and the anamnestic finding of a spider bite has made impossible a differential diagnosis of the pathology. The therapeutic approach, consisting in antibiotics and analgesics, is also reported. The administration of "antivenin" has not proven decisive to the resolution of the clinical picture. The diagnostic doubt has however represented a poorly influencing factor for a correct therapy.

Is hepatitis G virus a real risk for haemodialysis patients?

Haemodialysis patients are at high risk of developing liver disease due to blood-borne viral agents. At present hepatitis C virus (HCV) is the most common cause of infection in these patients. A new RNA virus of the Flaviviridae family, hepatitis G virus (HGV) has recently been cloned. HGV prevalence in haemodialysis patients ranges from 3.1% to 57.5%. The aim of this study has been to detect HGV-RNA in our haemodialysis patients in order to evaluate the prevalence of HGV and to correlate the viral presence to liver disease. A total of 79 patients, on haemodialysis for a mean of 52 months, were tested. 3 patients (3.8%) were HBsAG positive and 19 patients (24%) were HCV positive. 24 of the 79 (30%) patients had been transfused. Only 2 of the 79 patients (2.5%) were HGV positive. These patients were HBsAG and anti HCV negative, both had been previously transfused and showed no signs of liver disease.

Agrobacterium-mediated transformation of Artemisia absinthium L. (wormwood) and production of secondary metabolites.

Hairy roots were obtained after infection of Artemisia absinthium shoots with Agrobacterium rhizogenes strains 1855 and LBA 9402. The susceptibility to hairy root transformation varied between plant genotypes and bacterial strains. Hairy roots showed macroscopic differences from control root cultures. Southern blot hybridization confirmed the integration of T-DNA from both p1855 and pBin19, while polymerase chain reaction analysis indicated the presence of the neomycin phosphotransferase gene in the hairy root genome. Subcultured transformed root lines grew well in selective B5 agar-solidified medium containing kanamycin or rifampicin and without hormones. Shake-flask experiments with fast-growing root lines showed that 40 g l-1 was the best sucrose concentration for biomass production, yielding a 463-fold increase in dry weight after 28 days of culture. Great differences were found in the profiles of the essential oils isolated from normal and hairy roots. Gas chromatography/mass spectrometry analysis showed the oil produced by transformed cultures to be a mixture of 50 compounds with only one major component representing 37% of the oil content.