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The objective of this study was to investigate human leucocyte antigen (HLA) genes in patients chronically infected with hepatitis C virus (HCV) and to analyse the possible role of these genes in the progression of chronic hepatitis C. One hundred and forty-five (145) Brazilian patients infected only with HCV genotype 1 were evaluated. HLA class I (A*, B*, C*) and class II (DRB1*, DQA1*, DQB1*) typing were carried out by PCR-SSO, through Luminex technology. Associations were found with protection against development of liver damage by both DRB1*11 (5.0% versus 18.2%, P = 0.0016, OR = 0.23, CI 95% = 0.09–0.58; Pc=0.0208) and DRB1*11-DQA1*05-DQB1*03 haplotype (4.2% versus 15.3%, P = 0.0032; OR = 0.24, CI 95% = 0.08-0.64). Liver damage was associated with HLA-C*04 in patients with

Summary The objective of this study was to analyse the possible role of HLA polymorphism of chronically infected hepatitis C virus patients in the response outcome to treatment with pegylated interferon-alpha plus ribavirin. To that end, 144 Brazilian patients infected only with genotype 1 of the virus were treated with pegylated interferon-alpha at 1.5 μg kg−1 in conjunction with ribavirin (1000 mg if patient weight was 75 kg) for 48 weeks. The patients did not have concomitant HBV or HIV infections or liver disease, did not undergo previous antiviral treatment, and were followed up for 24 weeks after the end of treatment to assure they presented a sustained virological response. Patients were classified according to response to treatment in responsive (SVR), nonresponsive (NRS) and relapsers (REL). HLA class I and class II typing were carried out through PCR-SSO using Luminex technology. A statistically higher frequency of DRB1*11 patients was observed in the SVR group (39.6% vs. 14.3%P = 0.0012; Pc = 0.0156; OR = 3.94; 95% CI = 1.8–8.8). HLA-DQB1*03 patients were also more frequent in the SVR group, but the P value lost significance after Bonferroni correction (62.3% vs. 41.7%P = 0.024; Pc = 0.14, OR = 2.3; 95% CI = 1.14–4.60). HLA class II antigens can positively influence the response to treatment with pegylated interferon-alpha and ribavirin.

Angle calculations for a (2+3)-type diffractometer are presented with comprehensive derivations for both cases of either a vertical or horizontal sample configuration. This work focuses on some particular aspects of using area detectors in surface X-ray diffraction, namely the role of the detector rotation and the direct conversion of the angle-resolved diffraction signal recorded by the detector into a two-dimensional slice through reciprocal space.

The structure of epitaxially grown hexagonal boron nitride (h-BN) on the surface of a Ru(0 0 0 1) single crystal was investigated using surface X-ray diffraction, which showed the system to form a commensurate 14-on-13 superstructure. This result disagrees with previous reports on superstructures of the same system and arguments based on simple thermal expansion coefficient calculations. We argue that the larger observed superstructure forms because of the strong bonding of h-BN to Ru. In comparison to h-BN/Rh(1 1 1) it can accommodate more induced lateral in-plane strain- or lock-in energy over larger regions (referred to as the holes) within the superstructure, which itself can consequently become larger.

The counterion binding at a water/Aerosol-OT (AOT)/heptane microemulsion interface was treated in the context of the pseudo-phase ion exchange formalism. Two approaches were used to determine the selectivity coefficient for copper/sodium counterion binding at the AOT microemulsion interface: measurements of the Cu(II) concentration taken up by the reverse micelle in a Winsor II microemulsion system and steady-state emission quenching measurements of an anionic water-solubilized probe, the tris-(4,4'-dicarboxy-2,2'-bipyridine) ruthenium (II) ion. In addition, the selectivity coefficient for methyl viologen/sodium at the microemulsion surface was determined by the same photophysical technique. The value for copper (II)/sodium exchange (K(Cu/Na)) is 1.1+/-0.3 and that for methyl viologen/sodium (K(MV/Na)) is 0.9+/-0.3. The results show that the pseudo-phase ion exchange model can be used to obtain the selectivity coefficient in a microemulsion system.

We present a high-resolution surface X-ray diffraction study of hexagonal boron nitride (h-BN) on the surface of Rh(1 1 1). The previously observed commensurate 13-on-12 superstructure for this system is stable in the temperature range between room temperature and 830 °C. Surface X-ray diffraction measurements up to 830 °C on the superstructure show no sign of a shift towards a different superstructure, demonstrating the high thermal stability and strong bonding between film and substrate. At lower temperatures, an anomalous thermal expansion behaviour of the topmost surface region of rhodium is observed, where the rhodium in-plane lattice constant remains invariant. This can be explained by the (h-BN) single-layer being compressively strained, whereby the strong bonding to the substrate causes the latter to be tensile strained.

In aqueous solution, the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene glycol) (PEG) results in the formation of small aggregates or clusters of SDS attached to the PEG polymer chain. Selectivity coefficients for exchange of two monovalent (N -methyl-4-cyanopyridinium cation and Tl+ ) and two divalent (methylviologen cation and Cu2+ ) counterions at the surface of SDS-PEG clusters, determined employing photophysical techniques, are similar, but not identical, to those for exchange at the surface of SDS micelles in the absence of PEG. The principal factor affecting ion exchange selectivity in SDS-PEG clusters does not appear to be aggregate size or surface charge density but rather the presence of poly(oxyethylene) subunits at the aggregate surface.

Acinetobacter isolates from activated sludge treatment plants of forest industry were used as model organisms for polyphosphate accumulating bacteria to study excess phosphate uptake by the overplus phenomenon as well as luxury uptake of phosphate during growth. The initial, rapid phosphate uptake by the phosphorus-starved Acinetobacter isolates (the overplus phenomenon) followed the Michaelis-Menten model (maximum initial phosphate uptake rate 29 mg P g−1 dry mass (DM) h−1, half-saturation constant for excess phosphate uptake 17 mg P L−1). During the rapid uptake no growth was observed, but most cells contained polyphosphate granules. Also growth and luxury uptake of phosphate could be modeled with the Michaelis-Menten equation (maximum phosphate uptake rate 3.7–12 mg P g−1 DM h−1, half-saturation constant for growth 0.47–6.0 mg P L−1, maximum specific growth rate 0.15–0.55 h−1). © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng53: 304–309, 1997.

We demonstrate a route to manipulate the polarization and internal electric field of a complex oxide heterostructure using a layering sequence based on the LaAlO3-SrTiO3 interface. By combining sensitive atomic-level mapping of the structure using direct x-ray phase-retrieval methods with theoretical modeling of the electrostatic charge and polarization, we have devised a novel single-domain polar heterostructure. We find that ionic rearrangement results in strain and free energy minimization, and eliminates the polarization discontinuity leading to a two-fold increase of the spontaneous polarization towards the surface of an ultra-thin single-domain BaTiO3 film., APL Materials, 1 (6), ISSN:2166-532X

Three Acinetobacter isolates (identified by API 20 NE as A. baumannii, A. junii, A. lwoffii) from activated sludge treating forest-industry wastewaters were used as model organisms for polyphosphate-accumulating bacteria to optimize growth conditions for acinetobacters. The optimal concentrations of carbon, nitrogen, phosphorus, magnesium and potassium for the growth of these isolates were determined by using four sets of factorially designed experiments. Maximum growth was obtained with an average C:N:P ratio of 100:14:1.5 (on a weight basis) in the medium. The average N:P ratio of about 10 is twice the ratio that is usually considered optimal for bacterial growth in activated sludge. Magnesium and potassium are crucial for polyphosphate metabolism. A. baumannii did not respond to either magnesium or potassium additions, and A. junii had a linear response to potassium. Comparison of the optimal molar Mg:P (0.93–1.8) and K:P (0.56) ratios obtained for A. lwoffii and A. junii in the experiments to the corresponding ratios in the influent wastewaters indicates that magnesium and potassium would not limit growth and concomitant polyphosphate formation in acinetobacters. The results based on the optimal concentrations of elements in the medium may provide a better basis for optimizing the growth conditions than data on the chemical composition of bacterial cells.

The objective of this study was to investigate human leucocyte antigen (HLA) genes in patients chronically infected with hepatitis C virus (HCV) and to analyse the possible role of these genes in the progression of chronic hepatitis C. One hundred and forty-five (145) Brazilian patients infected only with HCV genotype 1 were evaluated. HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1) typing were carried out by PCR-SSO, through Luminex technology. Associations were found with protection against development of liver damage by both DRB1 11 (5.0% versus 18.2%, P=0.0016, OR=0.23, CI 95% = 0.09-0.58; Pc=0.0208) and DRB1 11-DQA1 05-DQB1 03 haplotype (4.2% versus 15.3%, P=0.0032; OR = 0.24, CI 95% = 0.08-0.64). Liver damage was associated with HLA-C 04 in patients with20 years of infection (38.4% versus 9.1%, P = 0.002, OR = 6.25, CI 95%=1.97-19.7; Pc=0.0238). It is concluded that HLA alleles can influence the development of liver damage in HCV type-1 chronically infected Brazilian patients.

The objective of this study was to analyse the possible role of HLA polymorphism of chronically infected hepatitis C virus patients in the response outcome to treatment with pegylated interferon-alpha plus ribavirin. To that end, 144 Brazilian patients infected only with genotype 1 of the virus were treated with pegylated interferon-alpha at 1.5 μg kg(-1) in conjunction with ribavirin (1000 mg if patient weight was75 kg and 1250 mg if75 kg) for 48 weeks. The patients did not have concomitant HBV or HIV infections or liver disease, did not undergo previous antiviral treatment, and were followed up for 24 weeks after the end of treatment to assure they presented a sustained virological response. Patients were classified according to response to treatment in responsive (SVR), nonresponsive (NRS) and relapsers (REL). HLA class I and class II typing were carried out through PCR-SSO using Luminex technology. A statistically higher frequency of DRB1*11 patients was observed in the SVR group (39.6% vs. 14.3%P = 0.0012; Pc = 0.0156; OR = 3.94; 95% CI = 1.8-8.8). HLA-DQB1*03 patients were also more frequent in the SVR group, but the P value lost significance after Bonferroni correction (62.3% vs. 41.7%P = 0.024; Pc = 0.14, OR = 2.3; 95% CI = 1.14-4.60). HLA class II antigens can positively influence the response to treatment with pegylated interferon-alpha and ribavirin.

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar ${\mathrm{LaAlO}}_{3}$ layer grown on ${\mathrm{SrTiO}}_{3}$ substrates. From the structural data, a complete screening of the ${\mathrm{LaAlO}}_{3}$ dipole field is observed for film thicknesses between 6 and 20 uc. For thinner films, an expansion of the $c$ axis of 2% matching the theoretical predictions for an electrostrictive effect is observed experimentally.

We present a direct comparison between experimental data and ab initio calculations for the electrostrictive effect in the polar LaAlO(3) layer grown on SrTiO(3) substrates. From the structural data, a complete screening of the LaAlO(3) dipole field is observed for film thicknesses between 6 and 20 uc. For thinner films, an expansion of the c axis of 2% matching the theoretical predictions for an electrostrictive effect is observed experimentally.

The evolution of the atomic structure of ${\mathrm{LaAlO}}_{3}$ grown on ${\mathrm{SrTiO}}_{3}$ was investigated using surface x-ray diffraction in conjunction with model-independent, phase-retrieval algorithms between two and five monolayers film thickness. A depolarizing buckling is observed between cation and oxygen positions in response to the electric field of polar ${\mathrm{LaAlO}}_{3}$, which decreases with increasing film thickness. We explain this in terms of competition between elastic strain energy, electrostatic energy, and electronic reconstructions. Based on these structures, the threshold for formation of a two-dimensional electron system at a film thickness of 4 monolayers is quantitatively explained. The findings are also qualitatively reproduced by density-functional-theory calculations.

The evolution of the atomic structure of LaAlO_{3} grown on SrTiO_{3} was investigated using surface x-ray diffraction in conjunction with model-independent, phase-retrieval algorithms between two and five monolayers film thickness. A depolarizing buckling is observed between cation and oxygen positions in response to the electric field of polar LaAlO_{3}, which decreases with increasing film thickness. We explain this in terms of competition between elastic strain energy, electrostatic energy, and electronic reconstructions. Based on these structures, the threshold for formation of a two-dimensional electron system at a film thickness of 4 monolayers is quantitatively explained. The findings are also qualitatively reproduced by density-functional-theory calculations.

The atomic structures of ultrathin ${\text{YBa}}_{2}{\text{Cu}}_{3}{\text{O}}_{7\ensuremath{-}x}$ (YBCO) films on ${\text{SrTiO}}_{3}(001)$ (STO) and $({\text{La}}_{x}{\text{Sr}}_{1\ensuremath{-}x})({\text{Al}}_{y}{\text{Ta}}_{1\ensuremath{-}y}){\text{O}}_{3}(001)$ (LSAT) were investigated with sub-Angstrom resolution using surface x-ray diffraction and the phase-retrieval direct-method difference map using the constraints of atomicity and film shift (DCAF). The model-independent electron densities which emerge from random initializations in DCAF are exceedingly stable. The films grow with a well-defined stacking sequence even when grown on substrates with mixed terrace termination. Only very minor out-of-plane deviations from bulk YBCO are observed in the film structures, although they are perfectly strained to the substrate and are therefore tetragonal. The films are superconducting, with critical temperatures for growth on STO and LSAT of 43 K and 70 K, respectively. These results have important implications for reliable structure determination of technologically relevant complex-metal oxide surfaces and interfaces.

The conducting interface of ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ heterostructures has been studied by hard x-ray photoelectron spectroscopy. From the Ti $2p$ signal and its angle dependence we derive that the thickness of the electron gas is much smaller than the probing depth of 4 nm and that the carrier densities vary with increasing number of ${\mathrm{LaAlO}}_{3}$ overlayers. Our results point to an electronic reconstruction in the ${\mathrm{LaAlO}}_{3}$ overlayer as the driving mechanism for the conducting interface and corroborate the recent interpretation of the superconducting ground state as being of the Berezinskii-Kosterlitz-Thouless type.

The availability of high‐brilliance hard x‐ray synchrotron radiation and the advent of novel photon counting area detectors have brought surface x‐ray diffraction (SXRD) into a new era. It is now possible to record large numbers of structure factors with much improved reliability within reasonable beamtime durations. As a result, structural determination of the surfaces and interfaces of complex crystallographic systems and heterostructures has now become feasible, especially in conjunction with phase‐retrieval methods. It is thereby hoped that detailed structural information will shed light on the unusual physical properties of these systems. Complex metal oxide systems investigated at the Materials Science beamline of the Swiss Light Source, including the surface of SrTiO3, the interface between LaAlO3 and SrTiO3, and the structure of YBa2Cu3O7 grown on NdGaO3, SrTiO3, and (LaSr)(AlTa)O3 will be presented as examples of what is now possible using SXRD.

The structure of a single layer of graphene on Ru(0001) has been studied using surface x-ray diffraction. A surprising superstructure containing 1250 carbon atoms has been determined, whereby 25 x 25 graphene unit cells lie on 23 x 23 unit cells of Ru. Each supercell contains 2 x 2 crystallographically inequivalent subcells caused by corrugation. Strong intensity oscillations in the superstructure rods demonstrate that the Ru substrate is also significantly corrugated down to several monolayers and that the bonding between graphene and Ru is strong and cannot be caused by van der Waals bonds. Charge transfer from the Ru substrate to the graphene expands and weakens the C-C bonds, which helps accommodate the in-plane tensile stress. The elucidation of this superstructure provides important information in the potential application of graphene as a template for nanocluster arrays.

The conducting interface of LaAlO3/SrTiO3 heterostructures has been studied by hard x-ray photoelectron spectroscopy. From the Ti 2p signal and its angle dependence we derive that the thickness of the electron gas is much smaller than the probing depth of 4 nm and that the carrier densities vary with increasing number of LaAlO3 overlayers. Our results point to an electronic reconstruction in the LaAlO3 overlayer as the driving mechanism for the conducting interface and corroborate the recent interpretation of the superconducting ground state as being of the Berezinskii-Kosterlitz-Thouless type.

Surface x-ray diffraction was used to determine the atomic structures of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ thin films, grown monolayer by monolayer on ${\mathrm{SrTiO}}_{3}$ by pulsed laser deposition. Structures for one-, two-, three-, four-, six-, and nine-monolayer-thick films were solved using the Coherent Bragg rod analysis phase-retrieval method and subsequent structural refinement. Four important results were found. First, the out-of-plane lattice constant is elongated across the substrate-film interface. Second, the transition from substrate to film is not abrupt, but proceeds gradually over approximately three unit cells. Third, Sr segregates towards the topmost monolayer of the film: we determined a Sr-segregation enthalpy of $\ensuremath{-}15\phantom{\rule{0.3em}{0ex}}\mathrm{kJ}∕\mathrm{mol}$ from the occupation parameters. Finally, the electronic bandwidth $W$ was used to explain the onset of magnetoresistance for films of nine or more monolayers thickness. Resistivity measurements of the nine monolayer-thick film confirm magnetoresistance and the presence of a dead layer with mostly insulating properties.

The complete atomic structure of a five-monolayer film of ${\mathrm{LaAlO}}_{3}$ on ${\mathrm{SrTiO}}_{3}$ has been determined for the first time by surface x-ray diffraction in conjunction with the coherent Bragg rod analysis phase-retrieval method and further structural refinement. Cationic mixing at the interface results in dilatory distortions and the formation of metallic ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{TiO}}_{3}$. By invoking electrostatic potential minimization, the ratio of ${\mathrm{Ti}}^{4+}/{\mathrm{Ti}}^{3+}$ across the interface was determined, from which the lattice dilation could be quantitatively explained using ionic radii considerations. The correctness of this model is supported by density functional theory calculations. Thus, the formation of a quasi-two-dimensional electron gas in this system is explained, based on structural considerations.

The complete atomic structure of a five-monolayer film of LaAlO3 on SrTiO3 has been determined for the first time by surface x-ray diffraction in conjunction with the coherent Bragg rod analysis phase-retrieval method and further structural refinement. Cationic mixing at the interface results in dilatory distortions and the formation of metallic La(1-x)SrxTiO3. By invoking electrostatic potential minimization, the ratio of Ti{4+}/Ti{3+} across the interface was determined, from which the lattice dilation could be quantitatively explained using ionic radii considerations. The correctness of this model is supported by density functional theory calculations. Thus, the formation of a quasi-two-dimensional electron gas in this system is explained, based on structural considerations.

There is a paucity of information regarding fallopian tube tumors of low malignant potential (LMP) in the literature.We present two cases representing alternative management options of low LMP of the fallopian tube.Although low malignant potential tumors of the ovary are relatively common, there are few reported cases of tumors of LMP originating in the fallopian tube. Treatment has been extrapolated from tumors of LMP of the ovary, and conservative fertility-sparing surgery and complete staging procedure remains controversial. We urge continued reporting of these fallopian tube tumors of LMP to enhance understanding of these rare tumors and to develop a more cohesive treatment plan.

An automated cluster algorithm is described, applicable to any image where a signal is to be analysed. The algorithm is employed in the context of surface X-ray diffraction data and extended to automate the data reduction process, which at present limits both the lead time to and the reliability of the retrieved structural information. A detailed evaluation of the constraints used to automate surface X-ray diffraction data analysis is provided. To overcome limitations of the algorithm and the experiment itself in certain geometries, the full field of view of area detectors is exploited to obtain orders of magnitude improvements in data collection. The method extends the surface X-ray diffraction technique to new systems and highlights the often archaic approach to the analysis of data collected with a two-dimensional detector.

Bacterial polyphosphate accumulation and denitrification are important processes in biological removal of nutrients from wastewater. It has been suggested that phosphorus accumulators are able to denitrify. However, the bacteria known as the most important phosphorus accumulators, belonging to the genus Acinetobacter are generally not known to denitrify. To clarify how commonly both physiological traits are present in the same organism, we screened 165 isolates from activated sludge and wastewater for their ability to denitrify, and the ability of the denitrifying isolates to accumulate polyphosphate. Of the 165 isolates, 149 were from acetate mineral medium (87 of these identified as Acinetobacter by the API 20 NE identification system) and 16 were from nutrient broth and nitrate medium. Only 15 of 165 isolates tested showed true respiratory denitrification activity. In the presence of acetylene they converted more than 80% of 5mM NO-3 to N2O in 6 days. None of the Acinetobacter isolates were among the 15 respiratory denitrifiers. The denitrifying isolates were identified as species of Pseudomonas, Agrobacterium, Pasteurella, Sphingomonas or could not be identified by the API 20 NE identification system. According to the BIOLOG identification system the denitrifiers were species of Pseudomonas, Hydrogenophaga, Citrobacter, Xanthomonas or they could not be identified. The ability of confirmed denitrifiers to accumulate phosphate was measured in experiments where cells pregrown under phosphorus limitation were exposed to phosphate (8 mg P/L) under aerobic conditions. The rates of excess phosphate uptake varied from 0.3 to more than 23 mg P/g dry matter/h. Rates for four isolates were higher than those reported for Acinetobacter strains. These results show that polyphosphate accumulation and denitrification in activated sludge can be carried out by the same organisms.

Twenty seven cases of neurocysticercosis, with clinical picture of acute meningitis, are described. Twenty (74.1%) patients are male; the age was 4 to 42 years (23.6 +/- 11.7 years). The etiologic diagnosis was defined by the complement fixation test (Weinberg) and/or enzyme-linked immunosorbent assay (ELISA) for cysticercosis in the cerebrospinal fluid (c. s. f.). Six patients that realized cranial computerized tomographic scan resembling neurocysticercosis. Twenty one (77.8%) have predominance of lymphomononuclear cells in the c. s. f. obtained in the admission to the hospital; in 6 (22.2%) there were predominance of polymorphonuclear neutrophils. In this c. s. f. lymphomononuclear pleocytosis and in three that have c. s. f. neutrophil pleocytosis, suggesting the diagnosis of neurocysticercosis. The treatment of acute neurocysticercosis was made with dexamethasone. All the patients survived and were transferred to the ambulatory of Neurology for follow-up and complementary treatment.

We present a structural analysis of the graphene/Ru(0001) system obtained by surface x-ray diffraction. The data were fit using Fourier-series expanded displacement fields from an ideal bulk structure, plus the application of symmetry constraints. The shape of the observed superstructure rods proves a reconstruction of the substrate, induced by strong bonding of graphene to ruthenium. Both the graphene layer and the underlying substrate are corrugated, with peak-to-peak heights of (0.82 +/- 0.15) A and (0.19 +/- 0.02) A for the graphene and topmost Ru-atomic layer, respectively. The Ru-corrugation decays slowly over several monolayers into the bulk. The system also exhibits chirality, whereby in-plane rotations of up to 2.0 degrees in those regions of the superstructure where the graphene is weakly bound are driven by elastic energy minimization.

A direct method for the retrieval of electron density maps from surface x-ray diffraction data is presented and its performance is evaluated. The method, DCAF (difference map using the constraints of atomicity and film shift), is based on the difference map iteration scheme and uses, apart from the traditional constraints of atomicity, positivity and film thickness, a novel constraint, which we have named the 'film shift', whereby the real space solution is shifted up by an out-of-plane unit cell size of the underlying bulk substrate material if the topmost region of the same thickness contains insignificant electron density. This relaxes the film thickness constraint, which is necessarily loose in order to accommodate structural uncertainties at the film–substrate interface due to intermixing, roughness, and heteroepitaxial strain. DCAF's performance was evaluated by retrieval of the electron density distribution from a real data set, recorded from a five-monolayer film of LaAlO3 on SrTiO3, which resulted in an electron density in good agreement with the previously solved structure. Importantly, the stability and reproducibility of the final solution compares favorably with constraint combinations in which the film shift projection is omitted, highlighting the power of this new method. In addition, an example of a full structural solution for a three-monolayer-thick film of La1−xSrxMnO3 on SrTiO3 is presented, where DCAF electron density retrieval followed by model building and refinement was conducted. It will be shown that DCAF can be successfully applied to thin films for retrieving physically meaningful electron densities, and that it can also serve as a starting point for subsequent structure refinement.

Two-dimensional electron gases in semiconductors have found use in applications such as optoelectronics, high-power radio-frequency and magnetoelectronic devices. The ability to grow heterostructures of oxides exhibiting similar effects is a significant step towards the fabrication of all-oxide devices. Here, we give an overview of recent studies of two-dimensional electron gases formed at the interface between polar and non-polar perovskites. We discuss the proposed explanations of the origin of the conductivity and properties of the ground state.

We have characterized for the first time in situ the growth of vanadium dioxide nanoparticulate films prepared by pulsed-laser deposition, using a five-circle x-ray diffractometer, in order to provide structural information as the films are grown. A vanadium metal target was ablated in the presence of a pulsed N2O reactive gas source, and films were grown on Si(001) and Al2O3(0001) substrates. Optical measurements confirmed that the films deposited in this way exhibit the well-known VO2 metal–insulator transition at approximately 70 °C. The VO2 films grown at room temperature on silicon substrates are amorphous and extremely smooth. These become considerably rougher upon thermal annealing, as the VO2 phase crystallizes out in the form of hemispherical islands. These films also contain traces of a V2O5 nanoparticle phase in the first few monolayers, although the degree of VO2 crystallinity in the nanoparticles is quite high. In contrast, the VO2 nanoparticles grown on the sapphire substrates are in the for...

Two young males with acne fulminans (AF) are described. In addition to severe skin lesions, they had musculoskeletal symptoms including bacteriologically negative osteolytic lesions in the clavicles. Both patients received antibiotics for suspected septic infections. The response was unsatis-factory in both patients, and combination treatment with prednisolone was started. A favourable response was observed, and a relapse occurring in the first patient was controlled by steroids alone. The possible pathomechanism of bone lesions in AF is discussed.

We present 5 young men who developed acne fulminans. During the acute, febrile illness, all had musculoskeletal symptoms, and X-ray and bone scan examinations revealed that 4 of the patients had osteolytic bone lesions. The disease was resistant to various antibiotics and one patient needed surgical trepanation of the sternum. No evidence of sepsis or bacterial osteomyelitis was found, as all bacteriological cultures proved negative and the tissue reaction was unspecific. The dermatopathogenetic origin of bone lesions in the present patients seems evident, but speculation that the etiology depends on immune mechanisms remains open.