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Cold desert soil microbiomes thrive despite severe moisture and nutrient limitations. In Eastern Antarctic soils, bacterial primary production is supported by trace gas oxidation and the light-independent RuBisCO form IE. This study aims to determine if atmospheric chemosynthesis is widespread within Antarctic, Arctic and Tibetan cold deserts, to identify the breadth of trace gas chemosynthetic taxa and to further characterize the genetic determinants of this process. H2 oxidation was ubiquitous, far exceeding rates reported to fulfill the maintenance needs of similarly structured edaphic microbiomes. Atmospheric chemosynthesis occurred globally, contributing significantly (p Chloroflexota, Firmicutes, Deinococcota and Verrucomicrobiota genomes. We identify a novel group of high-affinity [NiFe]-hydrogenases, group 1m, through phylogenetics, gene structure analysis and homology modeling, and reveal substantial genetic diversity within RuBisCO form IE (rbcL1E), and high-affinity 1h and 1l [NiFe]-hydrogenase groups. We conclude that atmospheric chemosynthesis is a globally-distributed phenomenon, extending throughout cold deserts, with significant implications for the global carbon cycle and bacterial survival within environmental reservoirs.

Aims The purpose was to compare the frequency of needs of patients with schizophrenia in forensic services across five European countries as assessed by both the patients and their care staff. Methods Patients with schizophrenia and a history of significant interpersonal violence were recruited from forensic psychiatric services in Austria, Germany, Italy, Poland and England. Participants’ needs were assessed using the Camberwell Assessment of Needs—Forensic Version (CANFOR). Multiple linear regression analyses were used to identify predictors of numbers of needs. Results In this sample, (n = 221) the most commonly reported need according to patients (71.0%) and staff (82.8%) was the management of psychotic symptoms. A need for information was mentioned by about 45% of staff and patients. Staff members reported a significantly higher number of total needs than patients (mean 6.9 vs. 6.2). In contrast, staff members reported a significantly lower number of unmet needs than patients (mean 2.0 vs. 2.5). Numbers of total needs and met needs differed between countries. Unmet needs as reported by patients showed positive associations with the absence of comorbid personality disorder, with higher positive symptom scores and lifetime suicide or self-harm history. Significant predictors of unmet needs according to staff were absence of comorbid personality disorder and higher positive as well as negative symptom scores according to PANSS. Conclusions Staff rated a significantly higher number of total needs than patients, while patients rated more unmet needs. This indicates that patients’ self-assessments of needs yield important information for providing sufficient help and support.

Rhabdomyosarcoma (RMS), an aggressive soft tissue sarcoma of the skeletal muscle generally affecting children and adolescents, shows extensive heterogeneity in histology, site and age of onset, clinical course, and prognosis. Tumorigenesis of RMS is multifactorial and genetic predisposition together with the family history of cancer may provide critical information to enhance the current knowledge and foster genetic counseling and testing. In our study, we evaluated the possible correlation of oncological family history with clinical outcomes in a cohort of RMS 512 patients and treated at the Pediatric Oncology Unit of our Institute. Family history was retrospectively collected from the specific ad hoc form available in medical records and filled in through an interview with the patients’ parents at the time of RMS diagnosis. While our series did not show a specific association between oncological family history and clinical variables, we observed an association with survival probabilities: among patients with a history of cancer-affected first-degree relatives at the time of the diagnosis, all children with alveolar RMS (ARMS) died of disease. Our study not only reports an interesting and not previously described association between a poor clinical outcome and ARMS in patients with young cancer-affected relatives, but also stimulates the discussion on oncological family history in RMS, to improve the clinical management of these young patients and their families.

Antimicrobial resistance is an escalating health crisis requiring urgent action. Most antimicrobials are natural products (NPs) sourced from Actinomycetota, particularly the Streptomyces. Underexplored and extreme environments are predicted to harbour novel microorganisms with the capacity to synthesise unique metabolites. Herring Island is a barren and rocky cold desert in East Antarctica, remote from anthropogenic impact. We aimed to recover rare and cold-adapted NP-producing bacteria, by employing two culturing methods which mimic the natural environment: direct soil culturing and the soil substrate membrane system. First, we analysed 16S rRNA gene amplicon sequencing data from 18 Herring Island soils and selected the soil sample with the highest Actinomycetota relative abundance (78%) for culturing experiments. We isolated 166 strains across three phyla, including novel and rare strains, with 94% of strains belonging to the Actinomycetota. These strains encompassed thirty-five ‘species’ groups, 18 of which were composed of Streptomyces strains. We screened representative strains for genes which encode polyketide synthases and non-ribosomal peptide synthetases, indicating that 69% have the capacity to synthesise polyketide and non-ribosomal peptide NPs. Fourteen Streptomyces strains displayed antimicrobial activity against selected bacterial and yeast pathogens using an in situ assay. Our results confirm that the cold-adapted bacteria of the harsh East Antarctic deserts are worthy targets in the search for bioactive compounds.

Candidatus phylum Eremiobacterota (formerly WPS-2) is an as-yet-uncultured bacterial clade that takes its name from Ca. Eremiobacter, an Antarctic soil aerobe proposed to be capable of a novel form of chemolithoautotrophy termed atmospheric chemosynthesis, that uses the energy derived from atmospheric H(2)-oxidation to fix CO(2) through the Calvin-Benson-Bassham (CBB) cycle via type 1E RuBisCO. To elucidate the phylogenetic affiliation and metabolic capacities of Ca. Eremiobacterota, we analysed 63 public metagenome-assembled genomes (MAGs) and nine new MAGs generated from Antarctic soil metagenomes. These MAGs represent both recognized classes within Ca. Eremiobacterota, namely Ca. Eremiobacteria and UBP9. Ca. Eremiobacteria are inferred to be facultatively acidophilic with a preference for peptides and amino acids as nutrient sources. Epifluorescence microscopy revealed Ca. Eremiobacteria cells from Antarctica desert soil to be coccoid in shape. Two orders are recognized within class Ca. Eremiobacteria: Ca. Eremiobacterales and Ca. Baltobacterales. The latter are metabolically versatile, with individual members having genes required for trace gas driven autotrophy, anoxygenic photosynthesis, CO oxidation, and anaerobic respiration. UBP9, here renamed Ca. Xenobia class. nov., are inferred to be obligate heterotrophs with acidophilic adaptations, but individual members having highly divergent metabolic capacities compared to Ca. Eremiobacteria, especially with regard to respiration and central carbon metabolism. We conclude Ca. Eremiobacterota to be an ecologically versatile phylum with the potential to thrive under an array of “extreme” environmental conditions.

Primary hypothyroidism commonly occurs after radiotherapy (RT), and coincides with increased circulating thyroid-stimulating hormone (TSH) levels.We tested therefore the protective effect of suppressing TSH with L-thyroxine during RT for medulloblastoma/PNET and Hodgkin lymphoma (HL) in a prospective cohort study. From1998 to 2001, a total of 37 euthyroid children with medulloblastoma/PNET plus 14 with HL, scheduled for craniospinal irradiation and mediastinum/neck radiotherapy, respectively, underwent thyroid ultrasound and free triiodothyronine (FT3), free thyroxine (FT4), and TSH evaluation at the beginning and end of craniospinal iiradiation. From 14 days before and up to the end of radiotherapy, patients were administered L-thyroxine checking every 3 days TSH to ensure a value < 0.3 μIU/mL. During follow-up, blood tests and ultrasound were repeated; primary hypothyroidism was considered an increased TSH level greater than normal range. Twenty-two/37 patients with medulloblastoma/PNET and all the 14 patients with HL were alive after a median 231 months from radiotherapy with 7/22 and 8/14 having correctly reached TSH levels < 0.3 μIU/mL and well matched for other variables. Twenty years on, hypothyroidism-free survival rates differed significantly, being 60% ± 15% and 15.6% ± 8.2% in TSH-suppressed vs. not-TSH suppressed patients, respectively (P = 0.001). These findings suggest that hypothyroidism could be durably prevented in two populations at risk of late RT sequelae, but it should be confirmed in a larger cohort.

Graphene integrated photonics provides several advantages over conventional Si photonics. Single layer graphene (SLG) enables fast, broadband, and energy-efficient electro-optic modulators, optical switches and photodetectors (GPDs), and is compatible with any optical waveguide. The last major barrier to SLG-based optical receivers lies in the low responsivity - electrical output per optical input - of GPDs compared to conventional PDs. Here we overcome this shortfall by integrating a photo-thermoelectric GPD with a Si microring resonator. Under critical coupling, we achieve $>$90% light absorption in a $\sim$6 $��$m SLG channel along the Si waveguide. Exploiting the cavity-enhanced light-matter interaction, causing carriers in SLG to reach $\sim$400 K for an input power of $\sim$0.6 mW, we get a voltage responsivity $\sim$90 V/W, demonstrating the feasibility of our approach. Our device is capable of detecting data rates up to 20 Gbit/s, with a receiver sensitivity enabling it to operate at a 10$^{-9}$ bit-error rate, on par with mature semiconductor technology. The natural generation of a voltage rather than a current, removes the need for transimpedance amplification, with a reduction of the energy-per-bit cost and foot-print, when compared to a traditional semiconductor-based receiver., 11 pages, 5 figures

Interlayer excitons in layered materials constitute a novel platform to study many-body phenomena arising from long-range interactions between quantum particles. Long-lived excitons are required to achieve high particle densities, to mediate thermalisation, and to allow for spatially and temporally correlated phases. Additionally, the ability to confine them in periodic arrays is key to building a solid-state analogue to atoms in optical lattices. Here, we demonstrate interlayer excitons with lifetime approaching 0.2 ms in a layered-material heterostructure made from WS2 and WSe2 monolayers. We show that interlayer excitons can be localised in an array using a nano-patterned substrate. These confined excitons exhibit microsecond-lifetime, enhanced emission rate, and optical selection rules inherited from the host material. The combination of a permanent dipole, deterministic spatial confinement and long lifetime places interlayer excitons in a regime that satisfies one of the requirements for simulating quantum Ising models in optically resolvable lattices. Excitons are quasiparticles consisting of an electron-hole pair and can be used to study many-body phenomenon. Here, the authors demonstrate on-demand quantum confinement of long-lived interlayer excitons in WS2/WSe2 heterostructures deposited on nanopatterned substrates.

BackgroundThe analysis of blow microbiota has been proposed as a biomarker for respiratory health analysis in cetaceans. Yet, we lack crucial knowledge on the long-term stability of the blow microbiota and its potential changes during disease. Research in humans and mice have provided evidence that respiratory disease is accompanied by a shift in microbial communities of the airways. We investigate here the stability of the community composition of the blow microbiota for 13 captive bottlenose dolphins over eight months including both sick and healthy individuals. We used barcoded tag sequencing of the bacterial 16S rRNA gene. Four of the dolphins experienced distinct medical conditions and received systemic antimicrobial treatment during the study.ResultsWe showed that each dolphin harboured a unique community of zero-radius operational taxonomic units (zOTUs) that was present throughout the entire sampling period (‘intra-core’). Although for most dolphins there was significant variation over time, overall the intra-core accounted for an average of 73% of relative abundance of the blow microbiota. In addition, the dolphins shared between 8 and 66 zOTUs on any of the sampling occasions (‘inter-core’), accounting for a relative abundance between 17 and 41% of any dolphin’s airway microbiota. The majority of the intra-core and all of the inter-core zOTUs in this study are commonly found in captive and free-ranging dolphins and have previously been reported from several different body sites. While we did not find a clear effect of microbial treatment on blow microbiota, age and sex of the dolphins did have such an effect.ConclusionsThe airways of dolphins were colonized by an individual intra-core ‘signature’ that varied in abundance relative to more temporary bacteria. We speculate that the intra-core bacteria interact with the immune response of the respiratory tract and support its function. This study provides the first evidence of individual-specific airway microbiota in cetaceans that is stable over eight months.

Background Resident soil microbiota play key roles in sustaining the core ecosystem processes of terrestrial Antarctica, often involving unique taxa with novel functional traits. However, the full scope of biodiversity and the niche-neutral processes underlying these communities remain unclear. In this study, we combine multivariate analyses, co-occurrence networks and fitted species abundance distributions on an extensive set of bacterial, micro-eukaryote and archaeal amplicon sequencing data to unravel soil microbiome patterns of nine sites across two east Antarctic regions, the Vestfold Hills and Windmill Islands. To our knowledge, this is the first microbial biodiversity report on the hyperarid Vestfold Hills soil environment. Results Our findings reveal distinct regional differences in phylogenetic composition, abundance and richness amongst microbial taxa. Actinobacteria dominated soils in both regions, yet Bacteroidetes were more abundant in the Vestfold Hills compared to the Windmill Islands, which contained a high abundance of novel phyla. However, intra-region comparisons demonstrate greater homogeneity of soil microbial communities and measured environmental parameters between sites at the Vestfold Hills. Community richness is largely driven by a variable suite of parameters but robust associations between co-existing members highlight potential interactions and sharing of niche space by diverse taxa from all three microbial domains of life examined. Overall, non-neutral processes appear to structure the polar soil microbiomes studied here, with niche partitioning being particularly strong for bacterial communities at the Windmill Islands. Eukaryotic and archaeal communities reveal weaker niche-driven signatures accompanied by multimodality, suggesting the emergence of neutrality. Conclusion We provide new information on assemblage patterns, environmental drivers and non-random occurrences for Antarctic soil microbiomes, particularly the Vestfold Hills, where basic diversity, ecology and life history strategies of resident microbiota are largely unknown. Greater understanding of these basic ecological concepts is a pivotal step towards effective conservation management.

Plasmonic biosensing has emerged as the most sensitive label-free technique to detect various molecular species in solutions and has already proved crucial in drug discovery, food safety and studies of bio-reactions. This technique relies on surface plasmon resonances in ~50 nm metallic films and the possibility to functionalize the surface of the metal in order to achieve selectivity. At the same time, most metals corrode in bio-solutions, which reduces the quality factor and darkness of plasmonic resonances and thus the sensitivity. Furthermore, functionalization itself might have a detrimental effect on the quality of the surface, also reducing sensitivity. Here we demonstrate that the use of graphene and other layered materials for passivation and functionalization broadens the range of metals which can be used for plasmonic biosensing and increases the sensitivity by 3-4 orders of magnitude, as it guarantees stability of a metal in liquid and preserves the plasmonic resonances under biofunctionalization. We use this approach to detect low molecular weight HT-2 toxins (crucial for food safety), achieving phase sensitivity~0.5 fg/mL, three orders of magnitude higher than previously reported. This proves that layered materials provide a new platform for surface plasmon resonance biosensing, paving the way for compact biosensors for point of care testing.

The thermal properties of airless icy surfaces are providing a wealth of information on their regolith structure after eons of space weathering. Numerous observations of the thermal cycles of Jupiter and Saturn icy satellites or Centaurs and TNOs have been acquired in the latest decades thanks to the Galileo and Cassini missions and to the Spitzer and Herschel telescopes. These observations and the latest developments on thermophysical modeling which have been achieved to link the thermal inertia to the regolith structure are reviewed here. Measured thermal inertias of these surfaces covered with water ice are very low, roughly between about 1 and 100 J/m2/K/s1/2. Often interpreted as due to unconsolidated or highly porous regoliths, these low values may result from a composition of amorphous ice or from the roughness of grains defacing contacts in a regolith of normal compaction. Taken together, thermal inertias appear to increase with probed depth and to decrease with heliocentric distance. This latter effect can be easily reproduced if heat transfer is dominated by radiation in pores, despite low temperatures, because the conduction through grains is limited, either due to the presence of amorphous ice or because of the roughness of grains.

Mitchell Peninsula is located towards the East of the Windmill Islands in eastern Antarctica. It is an ice-free polar desert, and knowledge of its soil microbial taxonomic composition is limited. In this study, we investigated the soil microbial taxonomic composition using multiplex 454 pyrosequencing targeting the bacterial 16S rRNA and the fungal ITS genes; and the bacterial and fungal abundances were estimated using quantitative PCR. In total, 40 bacterial and five fungal phyla were identified comprising 111 bacterial and 22 fungal classes, respectively. Mitchell Peninsula soil exhibited a unique bacterial taxonomic profile. In contrast to the usual dominance of Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes in polar and temperate soils, Mitchell Peninsula was rich in the poorly studied Chloroflexi (31.7 %), candidate divisions WPS-2 (8.1 %) and AD3 (5.1 %), while the commonly observed Bacteroidetes and Firmicutes were present in relative abundances below 1 %. The fungal community consisted of Ascomycota (77 %) and Basidiomycota (10 %), and was dominated by the lichenous fungal class Lecanoromycetes (46.4 %). Network analysis revealed the presence of several microbial clusters that each potentially occupied a different environmental niche, and fewer numbers of correlations were identified between bacteria within each cluster compared with the lichen community, where extensive community dynamics may be present. As Mitchell Peninsula exhibits a unique microbial taxonomic composition, not previously observed in any reported polar or temperate ecosystem, we believe it is a potential microbial biodiversity “hotspot”, which warrants further investigation to examine the role of the dominance of these uncharacterised candidate divisions in this extreme ecosystem.

Polymorphism of interleukin 28B gene represents a powerful outcome predictor for interferon-based regimens in hepatitis C virus infection. However, some studies report conflicting results. The predictive value of interleukin 28B genotype over the outcome interferon-α/ribavirin treatment was thoroughly evaluated and compared with virological predictors of response. Literature revision was performed on PubMed. Pooled odds ratios (ORs) were calculated by fixed- or random-effects models. Heterogeneity and publication bias were also assessed. Sixty-two eligible papers including 20 290 patients were retrieved. Both polymorphisms (rs12979860 and rs8099917) were strongly associated with response (OR=4.09 and 4.00, respectively), however, the association was weaker for subjects infected with viral genotypes 2 and 3 (OR=1.52 and 1.49, respectively). Compared with interleukin 28B genotype, the association with response was lower for baseline viremia (OR=2.15) and higher for rapid virological response (OR=13.86). These results provide a critical evaluation of interleukin 28B genotype as a pharmacogenetic predictor in hepatitis C patients.

Behçet's syndrome (BS) is a systemic, chronic, relapsing vasculitis, typically characterized by recurrent orogenital ulcers, ocular inflammation and skin manifestations; articular, vascular, gastroenteric and neurological involvement may also occur. Besides the other clinical features of BS, it seems relatively frequent that patients with BS develop a neurobehavioural syndrome, characterized by euphoria, bipolar disorders and paranoid attitudes, loss of insight/disinhibition, and indifference to their disease, defined as 'neuro-psycho-BS'. To date, the pathogenetic mechanism underlying neuro-psycho-BS has not been determined. It may be secondary to organic neurological involvement, or it may be related to poor quality of life and the relapsing course of the disease. Another engaging theory suggests that it could be related to the frequent observation of psychiatric symptoms during relapses or, in some cases, in the phases preceding reactivation of the disease; these elements suggest that psychiatric disorders in BS could represent a crucial element, whether a psychiatric subset or a distinct clinical feature of the disease. Moreover, it has been reported that cognitive impairment in BS can be seen with or without central nervous system involvement. Globally, psychiatric symptoms have been described as being multifaceted, ranging from anxiety disorders to depressive-bipolar disorders or to psychotic ones. In addition, some psychological characteristics of BS patients seem to predispose them to maladaptive stress management, which may lead to stress-related disorders, including anxiety and depression. Therefore, the aims of this review are to explore the epidemiology of neuro-psycho-BS by evaluating the relationship between the stress system and the multifaceted psychiatric manifestations in BS, and to summarize the therapeutic strategy used.

The attenuated vaccinia virus, modified vaccinia Ankara, has been engineered to deliver the tumor antigen 5T4 (TroVax®). Here, we report results from a randomized open-label phase II trial in castration-resistant prostate cancer patients in which TroVax was administered in combination with docetaxel and compared against docetaxel alone. The aim was to recruit 80 patients (40 per arm), but the study was terminated early due to recruitment challenges. Therefore, this paper reports the comparative safety and immunological and clinical efficacy in 25 patients, 12 of whom were treated with TroVax plus docetaxel and 13 with docetaxel alone. 5T4-specific immune responses were monitored throughout the study. Clinical responses were assessed by measuring changes in tumor burden by CT and bone scan and by quantifying PSA concentrations. TroVax was well tolerated in all patients. Of 10 immunologically evaluable patients, 6 mounted 5T4-specific antibody responses. Patients treated with TroVax plus docetaxel showed a greater median progression-free survival of 9.67 months compared with 5.10 months for patients on the docetaxel alone arm (P = 0.097; HR = 0.31; 95 % CI 0.08–1.24). Importantly, a pre-treatment biomarker previously demonstrated to predict 5T4 immune response and treatment benefit showed a strong association with 5T4 antibody response and a statistically significant association with progression-free survival in patients treated with TroVax plus docetaxel, but not docetaxel alone.

A bi-dimensional geometrical model was developed and numerically solved considering different cylindrical tungsten specimens, heated to temperatures above 3600 K with current pulses of about (500, 750, and 950) ms duration. A detailed analysis of these virtual experiments indicated large radial temperature differences in all the investigated cases. The range of validity of the long thin rod approximation was verified for various geometries and under different experimental conditions. The developed model may be used to estimate uncertainties due to the use of this approximation and to optimize experimental conditions in real experiments.

The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential to be in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultra-wide-band tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light emitting devices, to touch screens, photodetectors and ultrafast lasers. Here we review the state of the art in this emerging field., Review Nature Photonics, in press

Flow cytometry (FCM) is a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid. It uses the principles of light scattering, light excitation and the emission from fluorescent molecules to generate specific multiparameter data from particles and cells. The cells are hydrodynamically focussed in a sheath solution before being intercepted by a focused light source provided by a laser. FCM has been used primarily in medical applications but is being used increasingly for the examination of individual cells from environmental samples. It has found uses in the isolation of both culturable and hitherto non-culturable bacteria present infrequently in environmental samples using appropriate growth conditions. FCM lends itself to high-throughput applications in directed evolution for the analysis of single cells or cell populations carrying mutant genes. It is also suitable for encapsulation studies where individual bacteria are compartmentalised with substrate in water-in-oil-in-water emulsions or with individual genes in transcriptional/translational mixtures for the production of mutant enzymes. The sensitivity of the technique has allowed the examination of gene optimisation by a procedure known as random or neutral drift where screening and selection is based on the retention of some predetermined level of activity through multiple rounds of mutagenesis.

Current DNA extraction methods for parasites are labour-intensive and usually involve several steps, increasing the potential for cross-contamination. We describe here a closed-tube DNA extraction procedure based upon the use of a thermostable proteinase that enabled sensitive amplification of target loci from parasites from diverse lineages including Apicomplexa, Sarcomastgophora and Nematoda. Moreover, this procedure is not subject to cross-contamination and is readily adaptable to automation.

This paper reviews the rheumatological manifestations of scurvy, based on articles published in English from 1965 until October 2014, with a particular focus on rheumatological manifestations. Scurvy is a rare, uncommon disease in developed countries. Due to its clinical heterogeneity, the disease can easily mimic rheumatologic conditions leading to a delay in diagnosis and treatment.

The paper presents results of physico-chemical and biological investigations of a surface-engineered synthetic bone filler. Surface analysis confirms that the ceramic phosphate granules present a collagen nanolayer to the surrounding environment. Cell cultures tests show that, in agreement with literature reports, surface-immobilized collagen molecular cues can stimulate progression along the osteogenic pathway of undifferentiated human mesenchymal cells. Finally, in vivo test in a rabbit model of critical bone defects shows statistically significant increase of bone volume and mineral apposition rate between the biomimetic bone filler and collagen-free control. All together, obtained data confirm that biomolecular surface engineering can upgrade the properties of implant device, by promoting more specific and targeted implant-host cells interactions.

We review our recent results on the growth and characterization of silicon nanowires (SiNWs). Vapour-phase deposition techniques are considered, including chemical vapour deposition (CVD), plasma-enhanced chemical vapour deposition (PECVD), high-temperature annealing, and thermal evaporation. We present complementary approaches to SiNW production. We investigate the low-temperature (down to 300 °C) selective nucleation of SiNWs by Au-catalysed CVD and PECVD. Bulk production of SiNWs is obtained by thermal-vapour deposition from Si/SiO powders in a high-temperature furnace. In this case, SiNWs grow either by condensing on Au catalyst films, or by self-condensation of the vapour in a lower-temperature region of the furnace. Finally, we also achieve controlled growth by thermolysis of nanopatterned, multi-layered Si/Au thin-film precursors. The as-produced wires are compared in terms of yield, structural quality, and optical properties. Raman and photoluminescence spectra of SiNWs are discussed.

Androgen receptor (AR) overexpression is one of the characteristics of prostate cancer (PC) that progresses to hormone independence. An androgen-independent (AI) derivative, with much higher AR-mRNA and protein levels than the parental LNCaP cell line, whose proliferation was androgen dependent (AD), was used to explore the mechanism of AR overexpression. We found that a suppressor element (ARS), previously identified in mouse AR and located in the 5'-untranslated region of human AR gene, malfunctions in AI cells. Transfection of constructs that included ARS element into AD cells reduced the transactivating activities of both AR promoter and a heterologous SV40 promoter. The deletion of ARS resulted in an eightfold increase in AR-promoter activity in AD cells, but had no effect in AI cells. Moreover, the nuclear extracts of AD cells contained proteins that produced a specific, ARS-binding complex, while this complex appeared to have been lost from AI cells. Most importantly, treatment of AI cells with a demethylating agent or histone deacetylase inhibitors restored the lost ARS-binding complex. The restoration of the complex coincided with a reduced expression of AR-mRNA and protein and a reduced rate of AR-gene transcription, determined by nuclear run-on experiment. Thus, epigenetic transcriptional silencing of the suppressor protein(s) may be responsible for AR overexpression in AI cells, and its reversal in hormone-independent PC may normalize AR levels and restore their hormone dependence.

Insulin-like growth factor I (IGF-I) and its receptor (IGF-IR) are involved in growth of neurons. In the rat olfactory epithelium, we previously showed IGF-IR immunostaining in subsets of olfactory receptor neurons. We now report that IGF-IR staining was heaviest in the olfactory nerve layer of the rat olfactory bulb at embryonic days 18, and 19 and postnatal day 1, with labeling of protoglomeruli. In the adult, only a few glomeruli were IGF-IR-positive, some of which were unusually small and strongly labeled. Some IGF-IR-positive fibers penetrated deeper into the external plexiform layer, even in adults. In developing tissues, IGF-IR staining co-localized with that for olfactory marker protein and growth associated protein GAP-43, but to a lesser extent with synaptophysin. In the adult, IGF-IR-positive fibers were compartmentalized within glomeruli. IGF-I may play a role in glomerular synaptogenesis and/or plasticity, possibly contributing to development of coding patterns for odor detection or identification.

Tetrahedral amorphous carbon films have been produced by pulsed laser deposition, at a wavelength of 248 nm, ablating highly oriented pyrolytic graphite at room temperature, in a 10-2 Pa vacuum, at fluences ranging between 0.5 and 35 Jcm-2. Both (100) Si wafers and wafers covered with a SiC polycrystalline interlayer were used as substrates. Film structure was investigated by Raman spectroscopy at different excitation wavelength from 633 nm to 229 nm and by transmission Electron Energy Loss Spectroscopy. The films, which are hydrogen-free, as shown by Fourier Transform Infrared Spectroscopy, undergo a transition from mainly disordered graphitic to up to 80% tetrahedral amorphous carbon (ta-C) above a threshold laser fluence of 5 J cm-2. By X-ray reflectivity roughness, density and cross-sectional layering of selected samples were studied. Film hardness as high as 70 GPa was obtained by nanoindentation on films deposited with the SiC interlayer. By scratch test film adhesion and friction coefficients between 0.06 and 0.11 were measured. By profilometry we obtained residual stress values not higher than 2 GPa in as-deposited 80% sp3 ta-C films.

In the first part of the paper [D. Korytar and P. Bohacek: Czech. J. Phys. 50 (2000) 841] a three-dimensional reciprocal space concept based on two-beam dynamical theory of X-ray diffraction has been applied for studying the general case of a flat asymmetrical inclined Bragg diffractor. Based on the results obtained, precise equations for the incident and diffracted beams have been derived and analyzed in this second part of the paper. The out-of-diffraction-plane components of the incident and diffracted beams have been studied in detail. It was concluded that in comparison with the symmetrical inclined diffractor more than one order of magnitude increase of the out of plane component of the diffracted beam can be reached for the asymmetrical inclined diffractor in grazing emergence setting. At the same time the out of plane component of the incident beam is decreased below the out of plane component for the symmetrical inclined case.

The twins in self-frequency-doubling laser crystal Nd x Y(1−x)Al3(BO3)4 (NYAB) have been investigated by the transmission synchrotron topography and conventional Lang topography. It has been found that the twins in NYAB are similar to Brazil twins in natural quartz,i.e. the twin element is the mirror plane of type $$\left\{ {11\bar 20} \right\}$$ normal to the twofold (electric) axis. The twin is also discovered to have the shape of lamella and the twin boundaries are $$\left\{ {10\bar 11} \right\}$$ type. It is known that the contrast of this kind of twin lamella originates from the phase difference α between the X-ray diffracted at the twin boundaries. Using the atomic coordinates of the NYAB crystal and twinning structures, we have calculated the phase anglesθ H andθ T for the host crystal and twinning, respectively. The calculations show that the phase anglesθ H andθ T change with the reflections. Whenθ H andθ T are equal, the contrast due to the twin boundaries is invisible. Otherwise, the contrast of twin lamella can be observed.

White-beam synchrotron radiation and Lang topographic investigations of non-linear optical crystal KTiOAsO4 have been carried out. It is shown that domains and growth striations are primary planar defects in tungstate flux-grown single crystals. By selecting the wavelength to activate anomalous scattering effect near the absorption edge of the As atom, antiparallel ferroelectric domains are revealed, and in reflection pairshkl and\(\overline {hkl} \), the domains demonstrate contrast reversal. The differences in integrated intensity from a pair of opposite domains are also calculated and the harmonics in a Laue spot are given. Finally, the domain wall configurations are discussed in terms of the structural characteristics of KTiOAsO4.

A core consisting of minerogenic peat and organic-rich mineral sediments was collected at an altitude of 4275 m in the Ovejuyo valley, 100 km NE of La Paz in Bolivia. Age dating with 210Pb showed that the core represents approximately three centuries of sediment accumulation. None of the peats are ombrotrophic. Despite this, the Cd/Al, Cu/Al, Zn/Al, and Pb/Al ratios are all significantly higher in the surface layers, particularly in the top 6 cm: natural, abiological geochemical processes, therefore, cannot account for these elevated heavy metal/Al ratios. There are two possible explanations for the metal enrichments, relative to Al, in the surface layers: bioaccumulation by living plants, and anthropogenic atmospheric metal deposition. While the living plant layer may be responsible for the Cd, Cu, and Zn enrichments, this is an unlikely explanation for the Pb profile. In contrast to the other metals, the concentration of Pb in the first sample (dating from 1985-1994) is less than that of the second sample (dating from 1970-1985). The Pb/Al profile is consistent with the well documented, rapid increase in atmospheric Pb emissions during the present century (which accelerated following the introduction of leaded gasoline), and the decline in Pb pollution during the past 20 years (as a result of the introduction of unleaded gasoline). Thus, the Ovejuyo Valley mire has provided one of the first records of atmospheric Pb pollution in South America.

A method and an instrument has been developed for measuring almost simultaneously and continuously in time three different quantities: i) the heat evolved during the course of exothermic reactions, ii) the heat capacity and iii) the dielectric spectra of a liquid or solid sample. By using this instrument, we have studied the decrease in the d.c. conductivity and the increase in the relaxation time as molecules in an isothermally kept liquid chemically react to produce, irreversibly, a macromolecular structure until the liquid vitrifies and becomes rigid. The number of covalent bonds formed in the structure,n, has been calculated and the dielectric relaxation time, τ, is related ton. This τ increases progressively more rapidly withn, and decreases, of course, on increasing the temperature. A compensation between these two effects determines the dynamic behaviour observed during rate heating. The effect of temperature is found to predominate. Such observations have been made possible by means of the new instrument.

We present here a calorimetric method and the construction details of a differential calorimeter useful for studying the reactions in an electrolytic cell and more generally slow chemico-physical processes occurring in thermodynamically open systems. The method allows measurements of the heat balance of the cell, from which the enthalpy change of the process under investigation can be calculated. The theoretical description of the calorimetric cell and the results of several studies planned to describe the performances of the instrument up to the boiling point of the electrolytic solution are reported. The features of this calorimeter fulfil most of the requirements of ≪col fusion≫ experiments, where the heat production is the fundamental and controversial aspect. By controlling both the heat and the matter exchanged, the calorimeter can be utilised also to study bioenergetic processes,e.g. fermentation, microbial metabolism and biodegradation, and liquid phase chemical reactions, involving gases as reactants and/or products.

Relationships between the spatial and temporal distribution of long-lasting snow-cover and the spatial distribution of plant communities above timberline were studied on Mount Prado (2054 m), a representative sample area of the summit vegetation of the Northern Apennines (Italy). The spatial analysis was carried out by creating a geographic information system. Vegetation map and two snow-cover maps were both georeferenced to a scale 1 : 2000. The vegetation map is formed by 28 plant communities (including 7 combinations of communities, or vegetation mosaics) distributed into 277 map polygons. The maps were compared by an overlay procedure. The results show that the six plant communities (including three mosaics) which have a June snow-cover higher than 60% are diversified by a snow-melting gradient from early June to mid-July. The slowest snow melt corresponds to a snow-bed community (Salicetum herbaceae) and to a mesophytic grassland (Trifolium thalii-Festuca puccinellii community, Luzula alpino-pilosa variant).

This paper reviews and assesses the progress in conductor development across the world in advancing high-temperature superconducting science and technology towards the fabrication of superconducting transmission cables operating at 77 K. Materials, fabrication routes and the feasibility of high-temperature superconducting cables will be discussed.

Carbon fibres are a significant volume fraction of modern structural airframes. Embedded into polymer matrices, they provide significant strength and stiffness gains by unit weight compared with competing structural materials. Here we use the Raman G peak to assess the response of carbon fibres to the application of strain, with reference to the response of graphene itself. Our data highlight the predominance of the in-plane graphene properties in all graphitic structures examined. A universal master plot relating the G peak strain sensitivity to tensile modulus of all types of carbon fibres, as well as graphene, is presented. We derive a universal value of—average—phonon shift rate with axial stress of around −5ω0−1 (cm−1 MPa−1), where ω0 is the G peak position at zero stress for both graphene and carbon fibre with annular morphology. The use of this for stress measurements in a variety of applications is discussed., Embedding carbon fibres in polymer matrices provides significant gains in strength and stiffness. Here, the Raman G peak of carbon fibre is studied in relation to applied strain and referenced to graphene; the work could facilitate stress measurements of carbon fibre polymer composites.

We present the fabrication of a high optical quality single-walled carbon nanotubes (SWNTs) polyvinyl alcohol (PVA) composite film. The composites demonstrate strong saturable absorption at ∼1.5 μm, the spectral range for optical communications. By measuring the nonlinear transmission of a sub-picosecond pump pulse through the film, we were able to deduce a saturation fluence of ∼13.9 μJ/cm2 and a modulation depth ∼16.9% (in absorption) at a high pulse fluence ∼200 μJ/cm2. Transient saturable absorption is investigated by measuring the transmitted autocorrelation traces at various incident power levels. Observed side-peak suppression indicates a fast recovery time on the scale of ∼1 ps for our saturable absorber devices. Furthermore, we use these SWNT-PVA composite saturable absorbers as mode-lockers in an Er3+ fiber ring laser and achieve ∼560 fs pulse generation with good jitter performance and long term stability. The laser performance is also associated with the parameters of our SWNT based saturable absorber.

WE report results from the first stellar occultation by Titan ever observed. As predicted by Wasserman1, on 3 July 1989 the bright star 28 Sagittarii (visual magnitude, V ≈ 5.5), passed behind Saturn's giant moon ( V ≈ 8.3), which is the only body in the Solar System that, like the Earth, has a dense, nitrogen-rich atmosphere2. The event, visible from Europe, North Africa and the Middle East, allowed us to probe Titan's atmosphere in an altitude range of ∼ 250–500 km (a pressure range of ∼250-1 μbar), where until now, there has been an 'information gap' between infrared and ultraviolet Voyager observations3–5. We also detected a central flash as the centre of Titan's shadow passed at a few tens of kilometres from Paris. This central flash allows us to estimate a finite oblateness of Titan's stratosphere, which could arise from a super-rotation of Titan's atmosphere.

Atomic vibrations are partially screened by electrons. In a metal this screening can change rapidly for vibrations associated to certain points of the Brillouin zone, entirely determined by the shape of the Fermi surface. The consequent anomalous behaviour of the phonon dispersion is called Kohn anomaly. Graphite is a semimetal. Nanotubes can be metals or semiconductors. We demonstrate that two Kohn anomalies are present in the phonon dispersion of graphite and that their slope is proportional to the square of the electron-phonon coupling. Metallic nanotubes have much stronger anomalies than graphite, due to their reduced dimensionality. Semiconducting nanotubes have no Kohn anomalies.

Grazing incidence x-ray reflectivity has been employed to investigate ultra-thin films of tetrahedral amorphous carbon (ta-C) grown with an S-bend filtered cathodic vacuum arc. The results indicate that x-ray reflectivity can be used as a metrological tool for thickness measurements on films as thin as 0.5 nm, which is lower than the range required for carbon overcoats for magnetic hard disks and sliders if they are to reach storage densities of 100 Gbits/in2. The density of the films was derived from the best-fit to simulated reflectivity profiles from models for the structural parameters. In such thin films, the x-rays are reflected mainly at the film substrate interface, rather than the outer surface, so that the film density is derived from analysisof the oscillations of the post-critical angle reflectivity.

Raman spectroscopy is a very popular, non-destructive tool for the structural characterisation of carbons. Raman scattering from carbons is always a resonant process, in which those configurations whose band gaps match the excitation energy are preferentially excited. The Raman spectra of carbons do not follow the vibration density of states, but consist of three basic features, the G and D peaks around 1600 and 1350 cm-1 and an extra T peak, for UV excitation, at ∼980–1060 cm-1. TheRaman spectra at any wavelength depend on 1) clustering of the sp2 phase, 2)bond length and bond angle disorder, 3) presence of sp2 rings or chains, and 4) the sp2/sp3 ratio. It will be shown how the basic features of the Raman spectra vary by rationalising them within a three-stage model of order of carbons. It is shown how the three-stage model can account for the vast range of experimental data available for Raman experiments at any excitation wavelength. This model can also account for apparently contradictory trends reported in literature, since the clustering of the sp2 phase and the sp3 to sp2 conversion are separately treated.

Carbon films of thickness down to 2 nanometers are necessary to achieve a storage density of 100 Gbit/in2 in magnetic hard disks. Reliable methods to measure the properties of these ultrathin films still have to be developed. We show for the first time that combining Surface Brillouin Scattering (SBS) and X-ray reflectivity measurements the elastic constants of such films can be obtained. Tetrahedral amorphous carbon films were deposited on silicon, by an S bend filtered cathodic vacuum arc, which provides a continuous coverage on large areas free of macroparticles. Films of thickness down to 2 nm and density of ∼3 g/cm3 were produced and characterized. The dispersion relations of surface acoustic waves are measured by SBS for films of different thickness and for the bare substrate. Waves can be described by a continuum elastic model. Fitting of the dispersion relations, computed for given film properties, to the measured dispersion relations allows the derivation of the elastic constants. Fora 8 nm thick film we find a Young's modulus E around 400 GPa, with a shear modulus G lying in the 130 – 210 GPa interval. For a 4.5 nm thick film, E is around 240 GPa, with G lying in the 70 – 130 GPa interval. Results for even thinner films become highly sensitive to the precision of the substrate properties, and indicate that the above values are lower bounds. We thus show that we can grow and characterize nanometer size tetrahedral amorphous carbon films, which maintain their density and mechanical properties down to the nm range.

The factors controlling the position and intensity of the G3 and D peaks of the Raman spectra of disordered and amorphous carbons are separated in terms of a 3-stage model. The Raman spectra are shown to depend fundamentally on the degree of ordering of the sp2 sites, and only weakly or indirectly on the fraction of sp3 sites. Three factors control the G and D peaks; the perfection of graphitic order, replacing aromatic rings with olefinic chains and increasing the sp2 content. These rules allow us to state when the G3 peak position can be related reliably to sp3 content.

Diamond-like carbon (DLC) films have been prepared by pulsed laser deposition (PLD) (wavelength 248 nm), ablating highly oriented pyrolytic graphite (HOPG) at room temperature in a vacuum of 10−2Pa, at fluences between 0.5 and 35 Jcm−2. Films have been deposited on Si(100) with and without a SiC interlayer. Structural analysis, such as visible and UV Raman, Infrared and Electron Energy Loss (EEL) spectroscopies show that the films are hydrogen-free and undergo a transition, from mainly disordered graphitic to up to 80% tetrahedral amorphous carbon (ta-C), above a laser threshold fluence of 5 J cm−2. The measured residual stresses of as deposited ta-C films do not exceed 2 GPa. Scratch tests show excellent adhesion properties. Low friction coefficients (0.05-0.1) have been measured in ambient humidity. Nanoindentation indicates that film hardness is as high as 70 GPa

X-ray double crystal diffractometry has been used to assess the crystal quality of InGaAsP/ InP single heterostructures grown by liquid phase epitaxy. Diffraction profiles have been obtained in the parallel non-dispersive configuration, using Cu Kα1 radiation, 004 symmetric reflection and a perfect InP crystal as a monochromator. Several structures, with different lattice mismatches, ranging from positive to negative values, have been investigated. The epilayer Bragg peak was found to be as narrow as theoretically predicted, if thickness effects are taken into account. Pendellosung fringes have been observed at the low angle side of the peak, thus the epilayer thickness could be measured. Finally, the sample curvature has been evaluated from the broadening of the substrate Bragg peak and, when the broadening was sufficiently large, a good agreement with that calculated from the elastic theory has been found. All the results demonstrate that the structures investigated are characterized by a very high crystal quality.

Multiple discriminant analysis is a useful multivariate technique in vegetation studies that can be employed for several purposes, even if the underlying statistical assumptions are not satisfied. An example of application of this method is discussed: multiple discriminant analysis was successfully used for evaluating the predictivity of forest types defined by numerical classification of vegetation data with respect to soil variables.

Clients in psychotherapy with social workers, psychiatrists and psychologists learn things that they did not know previously. This learning modifies their view of reality and themselves. Clients learn that their problems are, to an extent universal, interpersonal—both “out from” themselves and “to” themselves from others, due to experiences in their past in their families, perhaps solvable by identifying with successful others, often due to unrealistic expectations about themselves, others and existence in general. Successful therapy is marked by culture-building interaction by the client and the therapist with the client's subjective understanding modified to enable greater autonomous action.

Clinical and experimental evidence indicates that carcinoid tumours of the stomach fundic mucosa represent another example of hormone-dependent neoplasm, gastrin being the hormone involved in tumour induction. In this context hyperplasia of fundic endocrine cells associated with chronic atrophic gastritis (CAG) and hypergastrinaemia is regarded as the most frequent preneoplastic lesion. However, the cell type involved in this hyperplasia has not been clarified. To elucidate this problem fundic endocrine cells were characterized ultrastructurally in 9 patients from which endoscopic gastric biopsies were obtained. ECL cells were the most frequent cell type in 8 cases, in 4 of which they were more numerous than all other cell types taken together. D1 cells were the most frequent type in one case while they were inconspicuous in the other cases. P cells were found with a frequency in each case intermediate between that of ECL cells and that of D1 cells. These results indicate that fundic endocrine cell hyperplasia occurring in hypergastrinaemic CAG is in most cases cytologically similar to that found in other hypergastrinemic conditions, in which the gastrin-dependent ECL cells were already found to prevail. They also explain why fundic carcinoids arising in CAG are mostly composed of ECL cells. The relation between ECL, D1 and P cells, if any, remains obscure.

A triple ultrastructural immunogold staining method for the simultaneous demonstration of three surface antigens of peripheral blood mononuclear cells at the electron microscope level is described. A six-step pre-embedding immunoelectron microscopy procedure was developed, using commercially available reagents. The CD11b antigen was first detected, through a two-step (indirect) method with 40 nm-sized gold particles; after a blocking step, the HLA-DR surface antigen was subsequently detected, through a two-step (biotin-streptavidin) method with 20 nm-sized gold particles; the CD4 antigen was finally detected, through a one-step (direct) method, using 5 nm-sized gold particles. Electron microscopic examination revealed firstly the presence of a triple-labelled cell subpopulation, which showed gold granules of the three sizes simultaneously decorating the cell membrane. Thus, the cells of such a subset simultaneously expressed the three antigens investigated. In contrast, either gold particles of only one size or no gold particles were observed on the cell surface of other subpopulations. This technique is a model demonstrating the importance of varying the size of particles in pre-embedding gold immunoelectron microscopy for a better analysis of the expression of surface antigens in isolated cells.