Electrical Sensing of the Thermal and Light-Induced Spin Transition in Robust Contactless Spin-Crossover/Graphene Hybrid Devices

Hybrid devices based on spin-crossover (SCO)/2D heterostructures grant a highly sensitive platform to detect the spin transition in the molecular SCO component and tune the properties of the 2D material. However, the fragility of the SCO materials upon thermal treatment, light irradiation, or contact with surfaces and the methodologies used for their processing have limited their applicability. Here, an easily processable and robust SCO/2D hybrid device with outstanding performance based on the sublimable SCO [Fe(Pyrz)₂ ] molecule deposited over chemical vapor deposition (CVD) graphene is reported, which is fully compatible with electronics industry protocols. Thus, a novel methodology based on growing an elusive polymorph of [Fe(Pyrz)₂ ] (tetragonal phase) over graphene is developed that allows a fast and effective light-induced spin transition in the devices (≈50% yield in 5 min) to be detected electrically. Such performance can be enhanced even more when a flexible polymeric layer of poly(methyl methacrylate) is inserted in between the two active components in a contactless configuration, reaching a ≈100% yield in 5 min.

Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

The critical current of a superconducting nanostructure can be suppressed by applying an electric field in its vicinity. This phenomenon is investigated throughout the fabrication and electrical characterization of superconducting tungsten-carbon (W-C) nanostructures grown by Ga[Formula: see text] focused ion beam induced deposition (FIBID). In a 45 nm-wide, 2.7 [Formula: see text]m-long W-C nanowire, an increasing side-gate voltage is found to progressively reduce the critical current of the device, down to a full suppression of the superconducting state below its critical temperature. This modulation is accounted for by the squeezing of the superconducting current by the electric field within a theoretical model based on the Ginzburg-Landau theory, in agreement with experimental data. Compared to electron beam lithography or sputtering, the single-step FIBID approach provides with enhanced patterning flexibility and yields nanodevices with figures of merit comparable to those retrieved in other superconducting materials, including Ti, Nb, and Al. Exhibiting a higher critical temperature than most of other superconductors, in which this phenomenon has been observed, as well as a reduced critical value of the gate voltage required to fully suppress superconductivity, W-C deposits are strong candidates for the fabrication of nanodevices based on the electric field-induced superconductivity modulation.

Editorial for the Special Issue on Nanofabrication with Focused Electron/Ion Beam Induced Processing

Focused electron beam (FEB) and focused ion beam (FIB) technologies have opened novel paths for material science research and technology at the micro and nano scales in recent decades [...].

Out-of-Plane Transport of 1T-TaS2/Graphene-Based van der Waals Heterostructures

Due to their anisotropy, layered materials are excellent candidates for studying the interplay between the in-plane and out-of-plane entanglement in strongly correlated systems. A relevant example is provided by 1T-TaS₂, which exhibits a multifaceted electronic and magnetic scenario due to the existence of several charge density wave (CDW) configurations. It includes quantum hidden phases, superconductivity and exotic quantum spin liquid (QSL) states, which are highly dependent on the out-of-plane stacking of the CDW. In this system, the interlayer stacking of the CDW is crucial for interpreting the underlying electronic and magnetic phase diagram. Here, atomically thin-layers of 1T-TaS₂ are integrated in vertical van der Waals heterostructures based on few-layers graphene contacts and their electrical transport properties are measured. Different activation energies in the conductance and a gap at the Fermi level are clearly observed. Our experimental findings are supported by fully self-consistent DFT+U calculations, which evidence the presence of an energy gap in the few-layer limit, not necessarily coming from the formation of out-of-plane spin-paired bilayers at low temperatures, as previously proposed for the bulk. These results highlight dimensionality as a key effect for understanding quantum materials as 1T-TaS₂, enabling the possible experimental realization of low-dimensional QSLs.

Superconducting properties of in-plane W-C nanowires grown by He+ focused ion beam induced deposition

Focused ion beam induced deposition (FIBID) is a nanopatterning technique that uses a focused beam of charged ions to decompose a gaseous precursor. So far, the flexible patterning capabilities of FIBID have been widely exploited in the fabrication of superconducting nanostructures, using the W(CO)₆ precursor mostly in combination with a focused beam of Ga⁺ ions. Here, the fabrication and characterization of superconducting in-plane tungsten-carbon (W-C) nanostructures by He⁺ FIBID of the W(CO)₆ precursor is reported. A patterning resolution of 10 nm has been achieved, which is virtually unattainable for Ga⁺ FIBID. When the nanowires are patterned with widths of 20 nm and above, the deposited material is superconducting below 3.5-4 K. In addition, nanowires with widths of 60 and 90 nm have been found to sustain long-range controlled nonlocal superconducting vortex transfer along 3 μm. Overall, these findings strengthen the capabilities of He⁺ FIBID of W-C in the growth and patterning of in-plane superconducting nanodevices.

3D superconducting hollow nanowires with tailored diameters grown by focused He+ beam direct writing

Currently, the patterning of innovative three-dimensional (3D) nano-objects is required for the development of future advanced electronic components. Helium ion microscopy in combination with a precursor gas can be used for direct writing of three-dimensional nanostructures with a precise control of their geometry, and a significantly higher aspect ratio than other additive manufacturing technologies. We report here on the deposition of 3D hollow tungsten carbide nanowires with tailored diameters by tuning two key growth parameters, namely current and dose of the ion beam. Our results show the control of geometry in 3D hollow nanowires, with outer and inner diameters ranging from 36 to 142 nm and from 5 to 28 nm, respectively; and lengths from 0.5 to 8.9 µm. Transmission electron microscopy experiments indicate that the nanowires have a microstructure of large grains with a crystalline structure compatible with the face-centered cubic WC_{1- x} phase. In addition, 3D electron tomographic reconstructions show that the hollow center of the nanowires is present along the whole nanowire length. Moreover, these nanowires become superconducting at 6.8 K and show high values of critical magnetic field and critical current density. Consequently, these 3D nano-objects could be implemented as components in the next generation of electronics, such as nano-antennas and sensors, based on 3D superconducting architectures.

Three-Dimensional Superconducting Nanohelices Grown by He+-Focused-Ion-Beam Direct Writing

Novel schemes based on the design of complex three-dimensional (3D) nanoscale architectures are required for the development of the next generation of advanced electronic components. He⁺ focused-ion-beam (FIB) microscopy in combination with a precursor gas allows one to fabricate 3D nanostructures with an extreme resolution and a considerably higher aspect ratio than FIB-based methods, such as Ga⁺ FIB-induced deposition, or other additive manufacturing technologies. In this work, we report the fabrication of 3D tungsten carbide nanohelices with on-demand geometries via controlling key deposition parameters. Our results show the smallest and highest-densely packed nanohelix ever fabricated so far, with dimensions of 100 nm in diameter and aspect ratio up to 65. These nanohelices become superconducting at 7 K and show a large critical magnetic field and critical current density. In addition, given its helical 3D geometry, fingerprints of vortex and phase-slip patterns are experimentally identified and supported by numerical simulations based on the time-dependent Ginzburg-Landau equation. These results can be understood by the helical geometry that induces specific superconducting properties and paves the way for future electronic components, such as sensors, energy storage elements, and nanoantennas, based on 3D compact nanosuperconductors.

Long-range vortex transfer in superconducting nanowires

Under high-enough values of perpendicularly-applied magnetic field and current, a type-II superconductor presents a finite resistance caused by the vortex motion driven by the Lorentz force. To recover the dissipation-free conduction state, strategies for minimizing vortex motion have been intensely studied in the last decades. However, the non-local vortex motion, arising in areas depleted of current, has been scarcely investigated despite its potential application for logic devices. Here, we propose a route to transfer vortices carried by non-local motion through long distances (up to 10 micrometers) in 50 nm-wide superconducting WC nanowires grown by Ga⁺ Focused Ion Beam Induced Deposition. A giant non-local electrical resistance of 36 Ω has been measured at 2 K in 3 μm-long nanowires, which is 40 times higher than signals reported for wider wires of other superconductors. This giant effect is accounted for by the existence of a strong edge confinement potential that hampers transversal vortex displacements, allowing the long-range coherent displacement of a single vortex row along the superconducting channel. Experimental results are in good agreement with numerical simulations of vortex dynamics based on the time-dependent Ginzburg-Landau equations. Our results pave the way for future developments on information technologies built upon single vortex manipulation in nano-superconductors.

Correlation of the Renal Cortex Volume With the Glomerular Filtration Rate in Live Donors for Renal Transplantation

INTRODUCTION

As a pretransplantation evaluation, renal function is determined by the glomerular filtration rate (GFR) with the use of renal scintigraphy (RS) and the estimated glomerular filtration rate (eGFR). To date, there are few studies that correlate renal cortex volume with eGFR determined with renal gammagram (GR) and eGFR by equations (Cockroft-Gault, Modification of Diet in Renal Disease, and Chronic Kidney Disease Epidemiology Collaboration equation) in Latin American living donors.

AIM

This study sought to determine whether there is correlation of the volume of the renal cortex by Herts equation with the GFR determined with renal gammagram (GFR-GR).

PATIENTS AND METHODS

This was an analytical, observational, and cross-sectional study. A review of the donor charts from January 1, 2014, to December 1, 2014, with a complete clinical file, kidney measurements, predonation tomography volume, and eGFR by different formulas and by renal scintigraphy.

RESULTS

Thirty-three donors were included, 51.5% male and 48.5% female. The mean age was 38.58 ± 10 years, with an average volume of 127.83 ± 28.30 mL, with diethylenetriamine-pentaacetate (DTPA) of 54.80 ± 7.13 mL/min/1.73 m² in the donated kidney. Spearman correlation showed the best association with the Herts equation (r = 0.346) reaching significance (P = .049) when comparing the different equations against the GFR with DTPA. Using the Bland-Altman method, the lowest variability and best significance was verified with the same equation compared to the other formulas (P = .0002).

CONCLUSIONS

There is no consensus regarding which is the best formula for calculating the GFR of both kidneys. Of the different formulas, the one that best correlated with the GFR was the Herts method, which uses the volume of the kidney.

Vertical Growth of Superconducting Crystalline Hollow Nanowires by He+ Focused Ion Beam Induced Deposition

Novel physical properties appear when the size of a superconductor is reduced to the nanoscale, in the range of its superconducting coherence length (ξ₀). Such nanosuperconductors are being investigated for potential applications in nanoelectronics and quantum computing. The design of three-dimensional nanosuperconductors allows one to conceive novel schemes for such applications. Here, we report for the first time the use of a He⁺ focused-ion-beam-microscope in combination with the W(CO)₆ precursor to grow three-dimensional superconducting hollow nanowires as small as 32 nm in diameter and with an aspect ratio (length/diameter) of as much as 200. Such extreme resolution is achieved by using a small He⁺ beam spot of 1 nm for the growth of the nanowires. As shown by transmission electron microscopy, they display grains of large size fitting with face-centered cubic WC_1-x phase. The nanowires, which are grown vertically to the substrate, are felled on the substrate by means of a nanomanipulator for their electrical characterization. They become superconducting at 6.4 K and show large critical magnetic field and critical current density resulting from their quasi-one-dimensional superconducting character. These results pave the way for future nanoelectronic devices based on three-dimensional nanosuperconductors.

Suspended tungsten-based nanowires with enhanced mechanical properties grown by focused ion beam induced deposition

The implementation of three-dimensional (3D) nano-objects as building blocks for the next generation of electro-mechanical, memory and sensing nano-devices is at the forefront of technology. The direct writing of functional 3D nanostructures is made feasible by using a method based on focused ion beam induced deposition (FIBID). We use this technique to grow horizontally suspended tungsten nanowires and then study their nano-mechanical properties by three-point bending method with atomic force microscopy. These measurements reveal that these nanowires exhibit a yield strength up to 12 times higher than that of the bulk tungsten, and near the theoretical value of 0.1 times the Young's modulus (E). We find a size dependence of E that is adequately described by a core-shell model, which has been confirmed by transmission electron microscopy and compositional analysis at the nanoscale. Additionally, we show that experimental resonance frequencies of suspended nanowires (in the MHz range) are in good agreement with theoretical values. These extraordinary mechanical properties are key to designing electro-mechanically robust nanodevices based on FIBID tungsten nanowires.

High-purity 3D nano-objects grown by focused-electron-beam induced deposition

To increase the efficiency of current electronics, a specific challenge for the next generation of memory, sensing and logic devices is to find suitable strategies to move from two- to three-dimensional (3D) architectures. However, the creation of real 3D nano-objects is not trivial. Emerging non-conventional nanofabrication tools are required for this purpose. One attractive method is focused-electron-beam induced deposition (FEBID), a direct-write process of 3D nano-objects. Here, we grow 3D iron and cobalt nanopillars by FEBID using diiron nonacarbonyl Fe2(CO)9, and dicobalt octacarbonyl Co2(CO)8, respectively, as starting materials. In addition, we systematically study the composition of these nanopillars at the sub-nanometer scale by atom probe tomography, explicitly mapping the homogeneity of the radial and longitudinal composition distributions. We show a way of fabricating high-purity 3D vertical nanostructures of ∼50 nm in diameter and a few micrometers in length. Our results suggest that the purity of such 3D nanoelements (above 90 at% Fe and above 95 at% Co) is directly linked to their growth regime, in which the selected deposition conditions are crucial for the final quality of the nanostructure. Moreover, we demonstrate that FEBID and the proposed characterization technique not only allow for growth and chemical analysis of single-element structures, but also offers a new way to directly study 3D core-shell architectures. This straightforward concept could establish a promising route to the design of 3D elements for future nano-electronic devices.

Functional nickel-based deposits synthesized by focused beam induced processing

Functional nanostructures fabricated by focused electron/ion beam induced processing (FEBIP/FIBIP) open a promising route for applications in nanoelectronics. Such developments rely on the exploration of new advanced materials. We report here the successful fabrication of nickel-based deposits by FEBIP/FIBIP using bis(methyl cyclopentadienyl)nickel as a precursor. In particular, binary compounds such as nickel oxide (NiO) are synthesized by using an in situ two-step process at room temperature. By this method, as-grown Ni deposits transform into homogeneous NiO deposits using focused electron beam irradiation under O2 flux. This procedure is effective in producing highly pure NiO deposits with resistivity of 2000 Ωcm and a polycrystalline structure with face-centred cubic lattice and grains of 5 nm. We demonstrate that systems based on NiO deposits displaying resistance switching and an exchange-bias effect could be grown by FEBIP using optimized parameters. Our results provide a breakthrough towards using these techniques for the fabrication of functional nanodevices.

Influence of the shape and surface oxidation in the magnetization reversal of thin iron nanowires grown by focused electron beam induced deposition

Iron nanostructures grown by focused electron beam induced deposition (FEBID) are promising for applications in magnetic sensing, storage and logic. Such applications require a precise design and determination of the coercive field (H C), which depends on the shape of the nanostructure. In the present work, we have used the Fe2(CO)9 precursor to grow iron nanowires by FEBID in the thickness range from 10 to 45 nm and width range from 50 to 500 nm. These nanowires exhibit an Fe content between 80 and 85%, thus giving a high ferromagnetic signal. Magneto-optical Kerr characterization indicates that H C decreases for increasing thickness and width, providing a route to control the magnetization reversal field through the modification of the nanowire dimensions. Transmission electron microscopy experiments indicate that these wires have a bell-type shape with a surface oxide layer of about 5 nm. Such features are decisive in the actual value of H C as micromagnetic simulations demonstrate. These results will help to make appropriate designs of magnetic nanowires grown by FEBID.

Arrays of densely packed isolated nanowires by focused beam induced deposition plus Ar⁺ milling

One of the main features of any lithography technique is its resolution, generally maximized for a single isolated object. However, in most cases, functional devices call for highly dense arrays of nanostructures, the fabrication of which is generally challenging. Here, we show the growth of arrays of densely packed isolated nanowires based on the use of focused beam induced deposition plus Ar(+) milling. The growth strategy presented herein allows the creation of films showing thickness modulation with periodicity determined by the beam scan pitch. The subsequent Ar(+) milling translates such modulation into an array of isolated nanowires. This approach has been applied to grow arrays of W-based nanowires by focused ion beam induced deposition and Co nanowires by focused electron beam induced deposition, achieving linear densities up to 2.5 × 10(7) nanowires/cm (one nanowire every 40 nm). These results open the route for specific applications in nanomagnetism, nanosuperconductivity, and nanophotonics, where arrays of densely packed isolated nanowires grown by focused beam deposition are required.

Improvement of domain wall conduit properties in cobalt nanowires by global gallium irradiation

Applications based on the movement of domain walls (DWs) in magnetic nanowires (NWs) require a good DW conduit behavior, i.e. a significant difference between DW nucleation and propagation fields. In this work, we have systematically studied how this property evolves in cobalt NWs grown by focused electron beam induced deposition (FEBID) as a function of global gallium irradiation, for irradiation doses up to 1.24 × 10(17) ions cm(-2). Whereas for high doses the DW conduit is lost, below 6.42 × 10(15) ions cm(-2) the difference between the two fields increases with irradiation, becoming up to ∼9 times larger than for non-irradiated wires, due to a strong increase in the nucleation field, while the propagation field remains approximately constant. This behavior stems from two effects. The first effect is a decrease in the magnetic volume of the parasitic halo around the NW, typically present in FEBID nanostructures, leading to the disappearance of weak nucleation centers. The second effect is the formation of a 20 nm outer shell with Co crystals about twice the size of those forming the NW core, causing a net increase of the local magnetocrystalline anisotropy. The results presented here are important for the potential use of magnetic NWs grown by FEBID in DW-based devices, and might also be of interest for magnetic NWs fabricated by other techniques.

Correlation between the magnetic imaging of cobalt nanoconstrictions and their magnetoresistance response

Scanning transmission x-ray microscopy (STXM) and magnetoresistance (MR) measurements are used to investigate the magnetic behavior of a nanoconstriction joining two micrometric electrodes (a pad and a wire). The reversal of the magnetization under variable external static magnetic fields is imaged. By means of a detailed analysis of the STXM images at the nanocontact area, the MR is calculated, based on diffusive anisotropic-MR. This MR agrees well with that obtained from electrical transport measurements, allowing a direct correlation between the MR signal and the magnetic reversal of the system. The magnetization behavior depends on the sample thickness and constriction dimensions. In 40 nm-thick samples, with 20 × 175 nm(2) contact areas, the magnetization at the two sides of the constriction forms a net angle of 90°, with a progressive evolution of the magnetization structure between the electrodes during switching. The MR in those cases has a more peaked shape than with 20 nm-thick electrodes and 10 × 80 nm(2) contact areas, where the magnetization forms 180° between them, with a wide domain wall pinned at the constriction. As a consequence of this configuration, a plateau in the MR is observed for about 20 Oe.

Nanoscale chemical and structural study of Co-based FEBID structures by STEM-EELS and HRTEM

Nanolithography techniques in a scanning electron microscope/focused ion beam are very attractive tools for a number of synthetic processes, including the fabrication of ferromagnetic nano-objects, with potential applications in magnetic storage or magnetic sensing. One of the most versatile techniques is the focused electron beam induced deposition, an efficient method for the production of magnetic structures highly resolved at the nanometric scale. In this work, this method has been applied to the controlled growth of magnetic nanostructures using Co2(CO)8. The chemical and structural properties of these deposits have been studied by electron energy loss spectroscopy and high-resolution transmission electron microscopy at the nanometric scale. The obtained results allow us to correlate the chemical and structural properties with the functionality of these magnetic nanostructures.

Ultrasmall functional ferromagnetic nanostructures grown by focused electron-beam-induced deposition

We have successfully grown ultrasmall cobalt nanostructures (lateral size below 30 nm) by optimization of the growth conditions using focused electron-beam-induced deposition techniques. This direct-write nanolithography technique is thus shown to produce unprecedented resolution in the growth of magnetic nanostructures. The challenging magnetic characterization of such small structures is here carried out by means of electron holography techniques. Apart from growing ultranarrow nanowires, very small Hall sensors have been created and their large response has been unveiled.

Focused electron beam induced etching of titanium with XeF2

Titanium is a relevant technological material due to its extraordinary mechanical and biocompatible properties, its nanopatterning being an increasingly important requirement in many applications. We report the successful nanopatterning of titanium by means of focused electron beam induced etching using XeF(2) as a precursor gas. Etch rates up to 1.25 × 10(-3) µm(3) s(-1) and minimum pattern sizes of 80 nm were obtained. Different etching parameters such as beam current, beam energy, dwell time and pixel spacing are systematically investigated, the etching process being optimized by decreasing both the beam current and the beam energy. The etching mechanism is investigated by transmission electron microscopy. Potential applications in nanotechnology are discussed.

Stigma and functioning in patients with bipolar disorder

OBJECTIVE

The aim of this study was to investigate the impact of self-rated stigma and functioning in patients with bipolar disorder in Latin-America.

METHODS

Two-hundred and forty-one participants with bipolar disorder were recruited from three Latin American countries (Argentina, Brazil, and Colombia). Functional impairment was assessed with the Functioning Assessment Short Test (FAST) and experiences with and impact of perceived stigma was evaluated using the Inventory of Stigmatizing Experiences (ISE).

RESULTS

Higher scores of self-perceived stigma were correlated with lower scores of functioning. After multiple regression analysis, being on disability benefit, current mood symptoms and functioning were associated with self-perceived stigma.

CONCLUSIONS

This is the first study to demonstrate an association between stigma and poor functioning in bipolar disorder. Possible implications of such findings for practitioners are discussed.

LIMITATIONS

The main limitation of this study is that the Inventory of Stigmatizing Experiences has not yet been validated in a population of bipolar patients in our countries. The sample size and heterogeneous clinical subjects from different countries and cultures limit the generalization of the present findings.

Direct observation of stress accumulation and relaxation in small bundles of superconducting vortices in tungsten thin films

We study the behavior of bundles of superconducting vortices when increasing the magnetic field using scanning tunneling microscopy and spectroscopy at 100 mK. Pinning centers are given by features on the surface corrugation. We find strong net vortex motion in a bundle towards a well-defined direction. We observe continuous changes of the vortex arrangements, and identify small displacements, which stress and deform the vortex bundle, separated by larger rearrangements or avalanches, which release accumulated stress.

Fe:O:C grown by focused-electron-beam-induced deposition: magnetic and electric properties

We systematically study the effect of oxygen content on the magneto-transport and microstructure of Fe:O:C nanowires deposited by focused-electron-beam-induced (FEBID) deposition. The Fe/O ratio can be varied with an Fe content varying between ∼ 50 and 80 at.% with overall low C content (≈16 ± 3 at.%) by adding H(2)O during the deposition while keeping the beam parameters constant as measured by energy dispersive x-ray (EDX) spectroscopy. The room-temperature magnetic properties for deposits with an Fe content of 66-71 at.% are investigated using the magneto-optical Kerr effect (MOKE) and electric magneto-transport measurements. The nanostructure of the deposits is investigated through cross-sectional high-resolution transmission electron microscopy (HRTEM) imaging, allowing us to link the observed magneto-resistance and resistivity to the transport mechanism in the deposits. These results demonstrate that functional magnetic nanostructures can be created, paving the way for new magnetic or even spintronics devices.

Magnetization reversal in individual cobalt micro- and nanowires grown by focused-electron-beam-induced-deposition

We systematically study individual micro- and nanometric polycrystalline cobalt wires grown by focused-electron-beam-induced-deposition. The deposits were grown in a range of aspect ratios varying from 1 up to 26. The minimum lateral dimension of the nanowires was 150 nm, for a thickness of 40 nm. Atomic force microscopy images show beam-current-dependent profiles, associated with different regimes of deposition. The magnetization reversal of individual nanowires is studied by means of the spatially resolved magneto-optical Kerr effect. Abrupt switching is observed, with a systematic dependence on the wire's dimensions. This dependence of the coercive field is understood in magnetostatic terms, and agrees well with previous results on cobalt wires grown with different techniques. The influence of compositional gradients along the structural profile on the magnetic reversal is studied by using micromagnetic simulations. This work demonstrates the feasibility of using this technique to fabricate highly pure magnetic nanostructures, and highlights the advantages and disadvantages of the technique with respect to more conventional ones.

Exploring the conduction in atomic-sized metallic constrictions created by controlled ion etching

A novel technique to establish atomic-sized contacts in metallic materials is shown. It is based on etching a (sub)micrometric electrode via a low-energy focused ion beam. The in situ measurements of the nanoconstriction resistance during the etching process permit control of the formation of atomic-sized constrictions with milling time, observing steps in the conductance in the range of the conductance quantum (G(0) = 2e(2)/h), just before entering the tunnelling regime. These constrictions are highly stable with time due to the adherence to a substrate, which allows further studies such as the detailed current-voltage transport investigation reported here. Scanning electron microscopy images are used to correlate the etching process and the constriction microstructure. The high control achieved in the process makes us suggest this technique as a promising route to study physical phenomena in the verge of the metal-tunnel conduction crossover.

Pulmonary embolism in a patient with severe congenital deficiency for factor V during treatment with fresh frozen plasma

Thrombosis is a rare complication in patients with congenital clotting factor deficiencies. In most cases, it is related to inherited procoagulant factors, use of central venous catheters or administration of coagulation factor concentrates. There are only a few case reports about thrombotic events during treatment with fresh frozen plasma (FFP). We report the case of a patient with homozygous inherited factor V deficiency, who developed a pulmonary embolism at a time of treatment with methylene blue treated FFP (MBFFP). The patient had only two other factors predisposing to thrombosis and both were acquired: obesity and bed rest. He started anticoagulant treatment with low molecular weight heparin (LMWH) while the deficient factors were replaced with MBFFP. After 8 days of treatment the patient developed a severe respiratory insufficiency. Pulmonary haemorrhage was considered among the differential diagnosis and LMWH was stopped. An inferior vena cava filter was placed without any further thrombotic complications. To our knowledge, there are no reports about patients with clotting factor deficiencies who developed a thrombotic event during treatment with MBFFP.

[Value of brief questionnaires in predicting smoking cessation in primary care]

OBJECTIVES

1. To study the factors predicting the giving-up of tobacco and to correlate the categories in the Smoker's Aid Programme (SAP) with levels of motivation and dependency, using brief questionnaires. 2. To find the annual percentage in the "winners" category, using the SAP methodology.

DESIGN

Prospective, observational, intervention study without a control group of a random sample of smokers attending primary care clinics.

SETTING

Four urban health centres in Zaragoza and Barcelona.

INTERVENTIONS

Systematic intervention on smokers in the change phase (SAP category). Use of questionnaires on motivation/dependency and of biochemical checks that they had actually given up.

PATIENTS

362 patients of whom 288 smokers (79.5%) took part. Average age was 40.85 (SD: 15.7). 60.8% were males.

MEASUREMENTS AND MAIN RESULTS

21.4% of the smokers had tobacco-related pathology. The number of previous attempts to give up smoking was 1.6 (SD: 2.9) Patients smoked an average of 13.4 cigarettes for 22.2 years (SD: 15.7). Average age at start of consumption was 17 (SD: 4.7). Initial motivation on the Richmond Test was 4.78 (SD: 3.2); and average dependency according to the modified Fagerström Test (TFm) was 0.6 (SD: 0.7). The number of SAP interventions was 1.9 (SD: 2.9). By the end 15.6% of the patients had achieved "winner" status, which was confirmed in 95.6% of them by the biochemical test. The logistic regression model confirmed that the factors predicting giving up tobacco were age, the initial levels of motivation and the initial number of cigarettes.

CONCLUSIONS

The short tests of motivation (Richmond) and, to a lesser extent, dependency (TFm) were good predictors of giving up tobacco and can be recommended in primary care.

Effectiveness of brief intervention on non-dependent alcohol drinkers (EBIAL): a Spanish multi-centre study

OBJECTIVE

The project was designed to compare the effectiveness of brief intervention (BI) versus simple advice (SA) in the secondary prevention of hazardous alcohol consumption.

METHODS

A randomized controlled trial with a 12-month follow-up was conducted. A total of 74 community-based primary care practices (328 physicians) located in 13 Spanish autonomous regions were recruited initially. Out of 546 men screened, only 229 were randomized into BI (n = 104) and SA (n = 125); 44.6% of practices finalized the study. The interventions on the BI group consisted of a 15-minute counselling visit carried out by physicians which included: (i) alcohol quantification, (ii) information on safe limits, (iii) advice, (iv) drinking limits agreement, (v) self-informative booklet with drinking diary record and (vi) unscheduled reinforcement visits. The SA group spent 5 minutes which included (i), (ii) and (iii).

RESULTS

There were no significant differences between both groups at baseline on alcohol use, age, socioeconomic status and CAGE score. After the 12-month follow-up there was a significant decrease in frequency of excessive drinkers (67% of BI group reached targeted consumption, versus 44% of SA; P < 0.001) as well as weekly alcohol intake reduction (BI reached 52 versus 32% in SA; P < 0.001). A trend to improve outcome with the number of reinforcement visits was found with BI. The only predictor of success was the initial alcohol consumption level.

CONCLUSIONS

Brief intervention is more effective than simple advice to reduce alcohol intake on adult men who attend primary care services in Spain.

[The evaluation of a self-measurement arterial pressure monitor: the OMRON-HM 722C]

OBJECTIVE

To evaluate a self-measuring blood pressure (BP) monitor, the OMRON-HM 722C.

DESIGN

Based on the protocol of the British Hypertension Society (BHS).

SETTING

Urban health centre.

PARTICIPANTS

A sample of 120 people (69 women) excluded those with a brachial perimeter under 24 centimetres or over 32.

MEASUREMENTS AND MAIN RESULTS

Each subject had four BP measurements in succession, separated by a minute: a) Manually, with a mercury sphygmomanometer (MSM); b) with self-measurement monitor; c) with self-measurement monitor; d) with MSM. Means and SD of systolic and diastolic pressures, means and SD of the differences and a graphic representation of these by the Bland and Altman method, were calculated. The cumulative percentages of differences the same as or below 5, 10 and 15 mm Hg were calculated. 89.1% of systolic BPs, and 92.5% of diastolic BPs, showed mean differences between monitor and observer equal to or below 5 mm Hg. The size of the differences was grade A in both cases, according to the BHS criteria.

CONCLUSION

The OMRON-HM 722C self-measuring monitor could be useful for self-measurement of BP at home by primary care patients.

[Multicenter study on the efficacy of advice for the prevention of alcoholism in primary health care]

BACKGROUND

The aim of this study was to analyse and to verify the efficacy of systematic advice for alcoholism prevention, assessing the reduction of the number in risk drinkers.

PATIENTS AND METHODS

A multicenter randomized controlled clinical trial was designed, to perform in general practitioner setting, on a sample of risk drinkers (alcohol intake > 280 g weekly, without dependence) sent by random in intervention group (systematic brief advice with support material and a five visit program during a year) and control group (once brief advice and a control in 1 year). The procedure to incorporate in both groups included physical exam, a blood test and the MALT questionnaire. A descriptive and analytic study on included variables was realised, assessing the percentage of drinkers who reduced alcohol intake below risk limit at the end of a year follow up, as well as the reduction intake in each group.

RESULTS

Of the 139 included males, 75 were in the intervention group and 64 in the control group. The percentage of patients not excluded by MALT > 10, and/or liver disease, that finished the 1 year follow up, was 46%, being the sample average age of 43 +/- 11.8. Patients included in both groups were initially comparable. At the end of a year follow up there were statistically significant differences in: percentage of risk drinkers who decreased alcohol intake below 280 g weekly (82% intervention group; 47% control group); percentage of reduction in GPT, GGT, triglycerides, systolic blood pressure and the MALT questionnaire.

CONCLUSIONS

The efficacy of isolated advice of general practitioner was proved to achieve the alcohol intake reduction below the risk limit accepted in male risk drinkers without alcohol dependence. The systematic follow up during a year significantly improves the results achieved with the isolated advice.