Dual-Mode Solidly Mounted Resonator-Based Sensor for Temperature and Humidity Detection and Discrimination

Sensors based on solidly mounted resonators (SMRs) exhibit a good set of properties, such as high sensitivity, fast response, low resolution limit and low production cost, which makes them an appealing technology for sensing applications. However, they can suffer from cross-sensitivity issues, as their response can be altered by undesirable ambient factors, such as temperature and humidity variations. In this work we propose a method to discriminate humidity variations from the general frequency response using an SMR specifically manufactured to operate in a dual-mode (displaying two close resonances). The two modes behave similarly towards humidity changes (-1.94 kHZ/(%RH)) for resonance one and -1.62 kHZ/(%RH) for resonance two), whereas their performance under temperature changes is significantly different, displaying 2.64 kHZ/°C for resonance one and 34.21 kHZ/°C for resonance two. This allows for the decoupling process to be carried out in a straightforward manner. Frequency response is tracked under different humidity conditions, in the -20 °C to room temperature region, proving that this behavior is reproducible in any given environment.

Analysis of spurious peaks at series resonance in solidly mounted resonators by combined BVD-Mason modelling

Solidly Mounted Resonators (SMRs) for high frequency RF filters and sensing applications often display spurious resonances that distort their frequency response. In this work, we try to identify the origin of spurious resonances accompanying the main series resonances in AlN-based SMRs with the help of modified Butterworth Van Dyke (BVD) and Mason's models. By manufacturing SMRs of different sizes and shapes and studying the influence of the position of the electrical probing spot, we have demonstrated both theoretically and experimentally that devices with larger areas are more likely to display these additional peaks. Our updated models accurately simulate the frequency response of the SMRs, revealing that spurious peaks are mostly related to the resistance of the electrodes. Our study clarifies the origin of the spurious resonances and offers solutions for both, the optimal design and measurement method of SMRs.

Homogeneity and Thermal Stability of Sputtered Al0.7Sc0.3N Thin Films

This work presents a study on the homogeneity and thermal stability of Al_0.7Sc_0.3N films sputtered from Al-Sc segmented targets. The films are sputtered on Si substrates to assess their structural properties and on SiO₂/Mo-based stacked acoustic mirrors to derive their piezoelectric activity from the frequency response of acoustic resonators. Post-deposition annealing at temperatures up to 700 °C in a vacuum are carried out to test the stability of the Al_0.7Sc_0.3N films and their suitability to operate at high temperatures. Despite the relatively constant radial composition of the films revealed from RBS measurements, a severe inhomogeneity in the piezoelectric activity is observed across the wafer, with significantly poorer activity in the central zone. RBS combined with NRA analysis shows that the zones of lower piezoelectric activity are likely to show higher surface oxygen adsorption, which is attributed to higher ion bombardment during the deposition process, leading to films with poorer crystalline structures. AFM analysis reveals that the worsening of the material properties in the central area is also accompanied by an increased roughness. XRD analysis also supports this hypothesis, even suggesting the possibility of a ScN non-piezoelectric phase coexisting with the AlScN piezoelectric phase. Thermal treatments do not result in great improvements in terms of piezoelectric activity and crystalline structure.

Direct growth of few-layer graphene on AlN-based resonators for high-sensitivity gravimetric biosensors

We present the successful growth of few-layer graphene on top of AlN-based solidly mounted resonators (SMR) using a low-temperature chemical vapour deposition (CVD) process assisted by Ni catalysts, and its effective bio-functionalization with antibodies. The SMRs are manufactured on top of fully insulating AlN/SiO2 acoustic mirrors able to withstand the temperatures reached during the CVD growth of graphene (up to 650 °C). The active AlN films, purposely grown with the c-axis tilted, effectively excite shear modes displaying excellent in-liquid performance, with electromechanical coupling and quality factors of around 3% and 150, respectively, which barely vary after graphene integration. Raman spectra reveal that the as-grown graphene is composed of less than five weakly coupled layers with a low density of defects. Two functionalization protocols of the graphene are proposed. The first one, based on a covalent binding approach, starts with a low-damage O2 plasma treatment that introduces a controlled density of defects in graphene, including carboxylic groups. After that, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) chemistry is used to covalently bind streptavidin molecules to the surface of the sensors. The second functionalization protocol is based on the non-covalent bonding of streptavidin on hydrophobic graphene surfaces. The two protocols end with the effective bonding of biotinylated anti-IgG antibodies to the streptavidin, which leaves the surface of the devices ready for possible IgG detection.

Low loss optical waveguides fabricated in LiTaO3 by swift heavy ion irradiation

Optical waveguides are fabricated by irradiation of LiTaO₃ with a variety of swift heavy ions that provide increasing levels of both nuclear and electronic damage rates, including C, F and Si ions, in the energy range of 15-40 MeV. A systematic study of the role of the ion fluence has been carried out in the broad range of 1e13-2e15 at/cm². The kinetics of damage is initially of nuclear origin for the lowest fluences and stopping powers and, then, is enhanced by the electronic excitation (for F and Si ions) in synergy with the nuclear damage. Applying suitable annealing treatments, optical propagation losses values as low as 0.1 dB have been achieved. The damage rates found in LiTaO₃ have been compared with those known for the reference LiNbO₃ and discussed in the context of the thermal spike model.

Tungsten Oxide Layers of High Acoustic Impedance for Fully Insulating Acoustic Reflectors

Gravimetric sensors based on solidly mounted resonators require fully insulating acoustic reflectors to avoid parasitics when operating in liquid media. In this work, we propose a new high-acoustic impedance material, tungsten oxide ([Formula: see text]), for acoustic reflectors. We have optimized the sputtering conditions of [Formula: see text] to obtain nonconductive layers with mass density around [Formula: see text] and acoustic velocities for the shear and the longitudinal modes up to 2700 and 4500 m/s, respectively. Compared to other conventionally used high impedance layers, [Formula: see text] films display several manufacture advantages, such as high deposition rates, great reproducibility, and good adhesion to underlying substrates. We have demonstrated the applicability of [Formula: see text] in practical shear mode bulk acoustic wave resonators that display good performance in liquid environments.

Mammalian Target of Rapamycin Inhibitor Monotherapy: Efficacy in Renal Transplantation

BACKGROUND

Calcineurin inhibitors (CNI) have failed to improve long-term outcomes in renal transplantation. Anti-proliferative and anti-angiogenic effects of mammalian target of rapamycin inhibitors (m-TOR) without nephrotoxicity could improve long-term survival in selected transplant recipients.

METHODS

We examined the evolution of 98 low-immunological risk renal transplant recipients on m-TOR monotherapy: 7 patients had induction without CNI and 91 were switched to m-TOR at 12 (p25-p75: 4-36) months after transplant.

RESULTS

Median follow-up time was 46 (p25-p75: 28.5-72.0) months. Fifteen recipients dropped out of the study (15.3%): 8 patients (8.2%) had to change their immunosuppressive treatment because of complications and 7 (7.1%) lost their grafts as a result of chronic rejection (4 cases) or death with a functioning graft (3 cases). At the end of follow-up, 83 of 98 (84.6%) recipients remained on monotherapy. The rates of recipient and graft survivals were 100% and 98.8% at 2 years and 96.9% and 93.5% at 4 years; the percentages of patients on monotherapy after 2 and 4 years were 95.2% and 85.2%, respectively. Renal function improved significantly and proteinuria decreased but not significantly. Those patients switched to m-TOR significantly received more erythropoietin, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, and hypotensive agents than before starting m-TOR, whereas there were no significant changes related to the use of statins, body weight, or percentage of diabetic patients. No case of non-compliance was reported.

CONCLUSIONS

This study supports the safety and efficacy of monotherapy with m-TOR in selected renal transplant recipients.

Assessment of the shear acoustic velocities in the different materials composing a high frequency solidly mounted resonator

Thin film acoustic resonators operating in the shear mode are being increasingly used for in-liquid sensing applications. A good design of such sensors requires accurate knowledge of the acoustic properties of the materials composing the whole device, which specifically includes their shear velocities. Here we present a method to assess the shear acoustic velocity of high and low acoustic impedance films commonly used in AlN-based solidly mounted resonators (SMRs), using test devices specifically designed to induce a half-wavelength resonance in the layer under study. Provided that the thickness and mass densities of all the layers are known, fitting the electrical response by Mason's model over a wide frequency range gives accurate values of both longitudinal and shear mode velocities. The assessment of porous and dense SiO2, Mo, W and Ta2O5 sputtered films yields shear velocities of 3150m/s, 3950m/s, 3450m/s, 3350m/s and 2900m/s, respectively. In addition, the resonances stimulated in the Ir and Au top electrodes enable deriving their shear modes velocities, with values of 3950m/s and 2350m/s, respectively.

Carbon nanotube growth on piezoelectric AlN films: influence of catalyst underlayers

Integration of carbon nanotube (CNT) forests in acoustic wave resonators has appeared interesting for sensing applications. High quality CNTs can be grown on piezoelectric AlN by using a stabilising layer for catalyst nanoparticles.

On the effectiveness of lateral excitation of shear modes in AlN layered resonators

We describe the fabrication and frequency characterization of different structures intended for the lateral excitation of shear modes in AlN c-axis-oriented films. AlN films are deposited on moderately doped silicon substrates covered either with partially metallic or fully insulating Bragg mirrors, and on insulating glass plates covered with insulating acoustic reflectors. TiOx seed layers are used to promote the growth of highly c-axis oriented AlN films, which is confirmed by XRD and SAW measurements. The excitation of the resonant modes is achieved through coplanar Mo electrodes of different geometries defined on top of the AlN films. All the structures analyzed display a clear longitudinal mode travelling at 11,000 m/s, whose excitation is attributed to the direction of the electric field (parallel to the c-axis) below the electrodes; this is enhanced when a conductive plane (metallic layer or Si substrate) is present under the piezoelectric layer. Conversely, only a weak shear resonance (6,350 m/s) is stimulated through the effect of coplanar electrodes, which is explained by the weakness of the electric field strength parallel to the surface between the electrodes. A significantly more effective excitation of shear modes can be achieved by normal excitation of AlN films with tilted c-axis.

Particle trapping and structuring on the surface of LiNbO3:Fe optical waveguides using photovoltaic fields

We report on the successful trapping and patterning of micro- and nanometric particles on the surface of LiNbO3 optical waveguides via photovoltaic tweezers. A waveguide configuration is used for the first time combined with this recently proposed technique. The electric field pattern is generated by light propagating in the waveguide, allowing us to separate the light channel with the region in which particles are deposited. Results on micro- and nanoparticle trapping, by two different deposition methods on two types of planar waveguides (by soft proton exchanged and by swift heavy ion irradiation), and using single-beam and two-beam interferometric configuration, are presented and discussed.

Mesenteric vein thrombosis after laparoscopic sleeve gastrectomy

Mesenteric vein thrombosis is a rare complication of bariatric laparoscopic surgery. We report a case of a 47-year-old man with obesity who had mesenteric vein thrombosis 14 days after laparoscopic sleeve gastrectomy. He was treated with heparin anticoagulation with a good therapeutic response. This case and literature review illustrate that mesenteric vein thrombosis has to be included in the differential diagnosis of abdominal pain after a bariatric procedure and listed formally as a complication of bariatric surgery.

Comparing the genetic structure of codling moth Cydia pomonella (L.) from Greece and France: long distance gene-flow in a sedentary pest species

Codling moth Cydia pomonella L. (Lepidoptera: Tortricidae) is the most important insect pest of apple production in Europe. Despite the economic importance of this pest, there is not information about the genetic structure of its population in Greece and the patterns of gene-flow which might affect the success of control programs. In this study, we analysed nine samples from apple, pear and walnut from various regions of mainland Greece using 11 microsatellite loci. Six samples from the aforementioned hosts from southern France were also examined for comparison. Bayesian clustering and genetic distance analyses separated the codling moth samples in two genetic clusters. The first cluster consisted mainly of the individuals from Greece, and the second of those from France, although admixture and miss-classified individuals were also observed. The low genetic differentiation among samples within each country was also revealed by F(ST) statistics (0.009 among Greek samples and 0.0150 among French samples compared to 0.050 global value among all samples and 0.032 the mean of the pair-wise values between the two countries). These F(ST) values suggest little structuring at large geographical scales in agreement with previous published studies. The host species and local factors (climatic conditions, topography, pest control programs) did not affect the genetic structure of codling moth populations within each country. The results are discussed in relation to human-made activities that promote gene-flow even at large geographic distances. Possible factors for the genetic differentiation between the two genetic clusters are also discussed.

High-acoustic-impedance tantalum oxide layers for insulating acoustic reflectors

This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators.

Swift heavy ion damage to sodium chloride: synergy between excitation and thermal spikes

Systematic data on the effect of irradiation with swift ions (Zn at 735 MeV and Xe at 929 MeV) on NaCl single crystals have been analysed in terms of a synergetic two-spike approach (thermal and excitation spikes). The coupling of the two spikes, simultaneously generated by the irradiation, contributes to the operation of a non-radiative exciton decay model as proposed for purely ionization damage. Using this scheme, we have accounted for the π-emission yield of self-trapped excitons and its temperature dependence under ion-beam irradiation. Moreover, the initial production rates of F-centre growth have also been reasonably simulated for irradiation at low temperatures ( < 100 K), where colour centre annealing and aggregation can be neglected.

Influence of crystal quality on the excitation and propagation of surface and bulk acoustic waves in polycrystalline AlN films

We investigate the excitation and propagation of acoustic waves in polycrystalline aluminum nitride films along the directions parallel and normal to the c-axis. Longitudinal and transverse propagations are assessed through the frequency response of surface acoustic wave and bulk acoustic wave devices fabricated on films of different crystal qualities. The crystalline properties significantly affect the electromechanical coupling factors and acoustic properties of the piezoelectric layers. The presence of misoriented grains produces an overall decrease of the piezoelectric activity, degrading more severely the excitation and propagation of waves traveling transversally to the c-axis. It is suggested that the presence of such crystalline defects in c-axis-oriented films reduces the mechanical coherence between grains and hinders the transverse deformation of the film when the electric field is applied parallel to the surface.

Tools for resistance monitoring in oriental fruit moth (Lepidoptera: Tortricidae) and first assessment in Brazilian populations

In southern Brazilian apple (Malus spp.) orchards, predominantly organophosphates are used to control the oriental fruit moth, Cydia molesta (Busck) (Lepidoptera: Tortricidae), but control failures often occur. Therefore the susceptibility of three C. molesta Brazilian populations was investigated to five insecticides of different groups and modes of action, in comparison with a susceptible laboratory strain mass reared in southern France for >10 yr. At the same time, comparative biochemical and genetic analysis were performed, assessing the activities of the detoxification enzymatic systems and sequencing a gene of insecticide molecular target to find out markers associated with resistance. The three Brazilian populations were significantly resistant to chlorpyrifos ethyl compared with the reference strain. One of the field populations that had been frequently exposed to deltamethrin treatments showed significant decreasing susceptibility to this compound, whereas none of the three populations had loss of susceptibility to tebufenozide and thiacloprid compared with the reference strain. All three populations had slight but significant increases of glutathione transferase and carboxylesterases activities and significant decrease of specific acetylcholinesterase activities compared with the reference. Only the most resistant population to chlorpyriphos exhibited a significantly higher mixed function oxidase activity than the reference. The acetylcholinesterase of females was significantly less inhibited by carbaryl in the Brazilian populations than in the reference strain (1.7-2.5-fold), and this difference was not expressed in the male moth. However, no mutation in the MACE locus was detected. These biological and molecular characterizations of adaptive response to insecticides in C. molesta provide tools for early detection of insecticide resistance in field populations of this pest.

Impact of peritonitis on long-term survival of peritoneal dialysis patients

The impact of each episode of peritonitis on long-term survival of peritoneal dialysis (PD) patients has yet to be defined.

OBJECTIVES

To determine the risk that each episode of peritonitis poses for patient survival and for the PD technique.

PATIENTS

1515 patients included in the Levante registry from 1 January 1993 to 31 December 2005.

METHODS

Retrospective analysis of a multicentre registry using Cox regression for time-dependent variables.

RESULTS

We analysed 1609 episodes of peritonitis in 716 patients (47.2%). In the univariate analysis, each case of peritonitis treated in the outpatient unit was associated with an increase in mortality (hazard ratio [HR] 1.99, P<.001), which was greater for episodes that required hospitalisation (HR 3.62, P<.001). Mortality increased with each successive episode in the same patient. Multivariate analysis confirmed the association of each case of peritonitis with lower long-term survival (HR 2.01, P<.001), with a different risk for episodes due to gram-positive and gram-negative bacteria and fungi (HR 1.73, 2.43 and 5.71, respectively; P<.001). Other variables associated with mortality were age, low residual renal function, absence of vascular access and comorbidity. Peritonitis was the only independent variable associated with technique failure (HR 1.29, P<.001), with a different risk for episodes due to gram-positive and gram-negative bacteria and fungi (HR 1.73, 2.43 and 5.71, respectively; P<.001).

CONCLUSIONS

Episodes of peritonitis negatively influence long-term survival of patients on PD.

Asthma diagnosis is not associated with obesity in a population of adults from Madrid

BACKGROUND

Several studies have suggested a relationship between asthma and obesity; however, this relationship is unclear when obesity is compared with bronchial hyperresponsiveness to methacholine.

AIM

To determine whether obesity is associated with a diagnosis of asthma.

METHODS

We conducted a cross-sectional study in a population of Spanish adults in the north of Madrid, Spain between 2003 and 2007. The patients included had experienced asthma symptoms during the previous year, but had a ratio of forced expiratory volume in the first second of expiration (FEV1) to forced vital capacity (FVC) of > 70%. Diagnosis was confirmed by the presence of symptoms and demonstration of bronchial hyperresponsiveness to methacholine. Obesity was measured by body mass index (BMI). Adjusted odd ratios (OR) were obtained by logistic regression.

RESULTS

Of a total of 1424 patients included, 251 (17.6%) were diagnosed with asthma. These patients were younger (P < .001) and had lower BMI (P < .001) and lung function parameters (FEV1 and FEV1/FVC ratio) than individuals without asthma (P < .001). After adjusting the model for age, gender, baseline FEV1, and FEV1/FVC ratio, patients with overweight or obesity were not more frequently diagnosed with asthma than those with normal weight (OR, 0.848 [95% confidence interval (CI), 0.59-1.20]; and OR, 0.616 [95% CI, 0.38-0.99], respectively). In addition, obese males were more frequently diagnosed with asthma than obese females (P < .041).

CONCLUSIONS

In this study, obesity and overweight were not associated with a diagnosis of asthma based on the presence of consistent symptoms and demonstration of airway responsiveness to methacholine.

Method for Testing Degree of Infectivity of Rhizobium meliloti Strains

The infectiveness of different strains of Rhizobium meliloti was tested with a technique that uses the addition of tetracycline to the root medium. To stop the infection, the antibiotic was added some time after the inoculation of Medicago sativa plants. A coefficient of infectivity for each strain was calculated according to the number of nodules that appeared with and without the addition of the antibiotic. This method seems useful in infectivity studies and is simpler and easier to perform than the test of competence between strains.

Analysis of Rhizobium meliloti Sym Mutants Obtained by Heat Treatment

Deletions in the pSym megaplasmid of Rhizobium meliloti were produced at a high frequency, and their lengths varied according to incubation temperature. Morphological differentiation into large and small colonies occurred after heat treatment. Small colonies elicited pseudonodules on alfalfa roots.

DCS Tx filters using AlN resonators with iridium electrodes

In this paper we present the design, fabrication technology, and characterization of BAW filters for the Digital Cellular System (DCS) Tx-band at 1.75 GHz. The filters are fabricated with AlN-based solidly mounted resonators (SMR) using iridium electrodes, in an attempt to increase the effective electromechanical coupling factor of the BAW devices and achieve the bandwidth requirements of DCS filters. The design and optimization of the filters is performed with a simulation tool that uses a circuit model to compute the filter frequency response. Tx filters with balanced inputs and outputs and different topologies are designed and fabricated. The experimental filter response is compared with the simulations to determine the suitability of each design. DCS bandwidth requirements are fulfilled by using Ir/AlN/Ir stacks.

Determination of minimal concentration of Piscirickettsia salmonis in water columns to establish a fallowing period in salmon farms

Abstract A highly sensitive real-time PCR procedure to detect and quantify the number of Pisciricketsia salmonis units in seawater samples from affected farm sites has been developed. The purpose was to determine a fallowing period that would allow safe restocking of the target farm with new fish. Bacterial load was determined in water samples by comparing the obtained amplification values against a standard curve generated by the amplification of known concentrations of the ITS-ribosomal component of P. salmonis DNA, cloned in a suitable vector. The standard curve was linear over the range of 10(1)-10(10) log units. Target samples were taken every 10 days over a 40-day period, at 5 m depth and at the surface. In a highly affected area of southern Chile, the number of bacterial units in farm water decreased to zero at day 50. Therefore, a fallowing period of 50 days post-removal of cages of affected fish appears to be appropriate before restocking. This procedure could be adapted to control disease problems because of other pathogens in fish farm waters.

Sputtered SiO2 as low acoustic impedance material for Bragg mirror fabrication in BAW resonators

In this paper we describe the procedure to sputter low acoustic impedance SiO(2) films to be used as a low acoustic impedance layer in Bragg mirrors for BAW resonators. The composition and structure of the material are assessed through infrared absorption spectroscopy. The acoustic properties of the films (mass density and sound velocity) are assessed through X-ray reflectometry and picosecond acoustic spectroscopy. A second measurement of the sound velocity is achieved through the analysis of the longitudinal lambda/2 resonance that appears in these silicon oxide films when used as uppermost layer of an acoustic reflector placed under an AlN-based resonator.

Worldwide variability of insecticide resistance mechanisms in the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae)

The activity of detoxifying enzymes (glutathione-S-transferases (GST), mixed-function oxidases (MFO), and esterases (EST)) and the presence of insensitive variants of target proteins (sodium channel and acetylcholinesterase) were examined in individual male and female codling moths. Twenty-nine populations from 11 countries and two laboratory strains were examined. Populations were classified as either unsprayed or sprayed. The ranges of enzyme activities across field populations varied 15-fold, 485-fold and fourfold for GST, MFO and EST, respectively. MFO was the only enzyme whose activity differed in a binomial classification of orchards based on their spray history. Few differences in enzyme activities were found due to sex among populations; and, in these cases, males had higher GST and lower MFO and EST activities than females. Activities of the three enzymatic systems across all populations were positively correlated. Populations from Greece, Argentina and Uruguay had significant percentages of moths with elevated GST and MFO activities. The co-occurrence of moths expressing both elevated MFO and low EST activities was found in conventional orchards from the Czech Republic and France. Chile was the only country where populations from treated orchards did not include a significant proportion of individuals with enhanced enzyme activity. The kdr mutation was found at significant levels in ten populations from five countries, including all French and Argentinean populations. The mutation in AChE was only detected in the Spanish population.

Genetic architecture in codling moth populations: comparison between microsatellite and insecticide resistance markers

The codling moth, Cydia pomonella, is renowned for developing resistance to insecticides and causing significant economic damage to pome fruits worldwide. In spite of its economic importance, little is known about the patterns of movement of this pest and the effects of insecticide treatment on the population genetic structure. Here, we investigated the genetic structure of the pest in 27 orchards from France, Italy, Armenia and Chile at seven microsatellite loci and two resistance markers [biochemical activity of cytochrome P450 oxidases and proportion of knockdown resistance (kdr) alleles in the sodium channel gene]. According to the microsatellite loci, we detected isolation by distance at the supranational scale but found no evidence of geographical structure among the 24 French orchards, which were mainly structured by the intensity of the insecticide treatments. Similarly, the highest levels of metabolic resistance associated with activity of the cytochrome P450 oxidases were detected in the most treated orchards. The kdr alleles were observed in southern France and Armenia where the pyrethroid insecticides were or have been intensively sprayed. The intensity of the insecticide treatments marginally affected the allelic richness in each orchard, but not the level of inbreeding. These results suggest important and high-distance gene flow among the codling moth populations, which were mainly structured according to the history of insecticide applications. Differences in mutation-migration-drift equilibrium among treated and untreated orchards also suggest that insecticide applications are the main force regulating the local dynamics of codling moth populations.

Circuital model for the analysis of the piezoelectric response of A1N films using SAW filters

In this paper we describe a method to assess the piezoelectric response of a piezoelectric thin film deposited on a conductive substrate. It is based on analyzing the frequency response of a surface acoustic wave (SAW) filter made on the piezoelectric thin film. For this analysis, we use a circuital model that takes into account the theoretical response of the ideal filter along with all the external and internal parasitic effects that deteriorate the response. Using this model, we can obtain the electromechanical coupling factor of the piezoelectric material (k2m) with good accuracy. If parasitic effects are not considered, k2m can be underestimated by a factor of up to 20. We have tested our model using SAW filters made on A1N thin films sputtered on substrates with different conductivities. A discussion on the relation between the different circuital elements and the physical properties of the filters also is provided.

Nonlinear optical waveguides generated in lithium niobate by swift-ion irradiation at ultralow fluences

A novel method to produce optical waveguides is demonstrated for lithium niobate (LiNbO(3)). It is based on electronic excitation damage by swift ions, i.e., with energies at approximately 1 MeV/amu or above. The new technique uses high-energy medium-mass ions, such as Cl, with electronic stopping powers above the threshold value for amorphization (5-6 keV/nm), reaching the maximum value a few micrometers inside the crystal. At the ultralow fluence regime (10(12)-10(13) cm(-2)) an effective nanostructured medium is obtained that behaves as an optical waveguide where light propagates transversally to the amorphous nanotracks created by every single impact. The method implies a reduction of 4 orders of magnitude with respect to He implantation. The optical waveguides present reasonable losses (~10 dB/cm) and significant second-harmonic generation (SHG) and electro-optic (EO) responses (>50% bulk) for the lowest fluences.

[Evaluation of viral load and antigenemia as markers for relapse cytomegalovirus infection in renal transplant recipients]

Cytomegalovirus (CMV) is a pathogen, commonly found in the donors and recipients of solid organ transplantation. CMV is one of the major causes of morbidity and mortality in these patients. Relapsing episodes of CMV infection occur in 23-33% of transplant patients which is likely a reflection of incomplete suppression of viral replication following antiviral treatment with intravenous ganciclovir. We have studied CMV DNA load and antigenemia as markers for relapse of CMV infection in 49 renal transplant patients out of 68 with CMV infection who received a course of intravenous ganciclovir among 300 transplants carried out between January of 2001 and June of 2005. Viral load and antigenemia were measured in blood samples obtained before, during and at the completion of treatment. We also studied different viral load as predictors of relapse CMV infection. Twelve (24.5%) of 49 recipients developed relapsing CMV infection. The relapsing group had higher viral loads after treatment than the no relapsing group. There was no difference in antigenemia level between both groups. The viral loads before and during the treatment, the age and sex of donors and recipients, inmunosupresión, percentage of seronegative recipients with seropositive donors, duration of the therapy and the percentage of patients with heavy immunosuppression were similar in the two groups, but the incidence of acute rejection was higher in the relapsing group. We also evaluated the range of viral load after treatment which is able to trigger the relapse of CMV infection. We conclude that CMV DNA load after treatment is a useful marker for individualizing antiviral treatment of CMV infection in renal transplant recipients. Acute rejection is a risk factor to the relapsing CMV infection.

[Perforation of the acalculous gallbladder in a renal transplant recipient with CMV infection]

We report the case of a renal transplant recipient who developed acute acalculous cholecyscitis resulting in gallbladder perforation. At admission CMV antigenemia was negative. Emergency laparatomy was performed and showed the gallbladder to be infarted with a perforation. The abdominal cavity contained two litres of sterile bilious fluid. The pathological report showed frequent endothelial cells contained intranuclear and intracitoplasmatic inclusion (fig. 1). Treatment with Ganciclovir iv was started after diagnosis, but a computerized tomography scan demonstrated severe acute pancreatitis (grade E. Baltazar). The patient developed multiorgan failure and died on 19th day after surgery. Necropsy showed cytomegalic inclusions in pancreas (fig. 2), gastrointerstinal tract, lung and graft. A necroticing pneumonia with Mycotic spores and hiphae was seen. Aspergillus was also observed in myocardium (fig. 3).

Evaluation of Organ Procurement in an Area Under the Influence of a Training Program

INTRODUCTION

The procurement of organs was evaluated in an area of 1,450,000 inhabitants. This area provides two international programs and two training courses for transplant coordinators. One of them deals with the entire process of donation and transplantation, and the other is a monographic course about family consent and donation request. One transplantation coordinator manages the area.

METHODS

The results of the last 6 years have been analyzed concerning the procurement of organ donors (related to brain death [BD] donors, exitus at the hospital, and the intensive care unit [ICU]); loss in the process, such as medically unsuitable; problem detection; and family refusals.

RESULTS

During the past 6 years the donor potential increased from 1.67% to 4.06%. The BD by exitus in the ICU increased from 7% to 14.01% (the average in Spain 12.2%); the cases of BD in ICU beds increased from 0.5% to 1.31% (average in Spain 0.8%). The loss for medical exclusion criteria decreased from 27% to 20% and in family refusals from 19.7% to 13.6%. The efficiency of the process in percentage of actual donations by BD increased from 52.4% to 65.3% (average in Spain 49%). The actual donors per million population (PMP) increased from 37 PMP to 59 PMP. The average number of organs obtained from donors increased from 3.1 to 3.6, and the transplants increased from 2.7 to 3.04 per donor. The average waiting period for a renal transplant was reduced from 365 days to 199 days.

CONCLUSION

The training of coordinators and the net system of regional coordinator, area coordinator, and hospital coordinator improved our donation rate.

[Malignant middle cerebral artery infarction: medical or surgical treatment?]

INTRODUCTION

Post-ischemic brain edema occurs in 10-20% of cases of infarction of the middle cerebral artery and is the main cause of early death following a completed stroke. This complication, which is known as malignant middle cerebral artery infarction (MMCI), has a mortality rate of 78% when treated medically and thus requires a different management, such as a decompressive craniectomy. The main aim of this study is to review this procedure.

DEVELOPMENT

We conducted a search in the literature published over the last 20 years on this subject. Most of the studies are series of clinical cases with very favourable surgical outcomes. In non-random case-control studies the mortality rate was seen to decrease in the surgical group, and more so if the intervention was carried out early, as compared to the group that underwent medical treatment. Another study that compared decompressive craniectomy with hypothermia showed a higher survival rate in the surgical group. The post-surgery morbidity rate has not been determined, although it seems to be lower in infarction of the non-dominant hemisphere and in younger patients.

CONCLUSIONS

The low degree of conclusiveness of the studies published to date only enables us to offer one practical opinion concerning this issue: decompressive craniectomy should be evaluated on an individual basis in patients with MMCI who do not respond to medical treatment. The final decision and the most appropriate moment to operate on the patient following the stroke must be based on the family's opinion and on the clinical features of the patient.

[Fever and cavitary infiltrate in a renal transplant recipient]

Aspergillus infection is a rare but devastating complication following organ transplantation with high mortality rate. Aspergillus fumigatus is the most common cause of invasive aspergillosis. This fungus is present in the environment worldwide. Aspergillus infection is mainly acquired by inhalation of spores and several nosocomial infections in transplant recipient have been associated with construction work at hospitals. Risk factors for invasive aspergillosis include administration of steroid boluses, history of cytomegalovirus infection, neutropenia and prolonged antibiotic use after transplantation. Successful treatment depends on three factors: early diagnosis, aggressive antifungal therapy and decrease or removal of immunosuppression. Amphotericin deoxycholate has been the standard treatment for many years but lipid preparations for amphotericin are now used due to their significantly fewer adverse effects. A number of new antifungal drugs are now being developed including new azoles such as voriconazol and echinocandin. Invasive aspergillosis has a high mortality rate more than 95% when cerebral dissemination is demonstrated. We report the case of a 47 years old woman who received a cadaveric renal graft and developed pulmonary aspergillosis with fulminant cerebral dissemination two months later. The diagnosis of pulmonary aspergillosis was by culture isolation obtained from bronchioalveolar lavage. Removal of immunosuppresive agents and liposomal amphotericin B therapy were started shortly after admission. Brain CT scan performed on the 12th day showed cerebral dissemination. The recipient died two days later. Our patient had several risk factors such as the administration of steroid boluses and cytomegalovirus infection. Invasive aspergillosis must be always included in the differential diagnosis of fever and pulmonary disease in the renal transplant recipient.

Developmental downregulation of rhizobial genes as a function of symbiosome differentiation in symbiotic root nodules of Pisum sativum

•  The expression of nodA and dctA genes of Rhizobium leguminosarum bv. viciae has been studied in mutant nodules of pea (Pisum sativum L.), blocked at the following developmental stages: infection thread development inside the nodule (Itn); infection droplet differentiation (Idd); bacteroid differentiation after endocytosis (Bad); and nodule persistence (Nop). •  With the use of reporter fusions to these symbiotic bacterial genes it was shown that both nodA and dctA were expressed at all developmental stages, with a pattern similar to that of constitutive, symbiosis-unrelated genes. •  As well as two constitutively expressed genes, both nodA and dctA genes seemed to be subjected to gradual downregulation in nodule bacteria, correlating with the stage of bacteroid differentiation reached. No such effect was observed for the symbiotic, oxygen-regulated fixN gene. The bacteroid development stage also appeared to be related to the ability of bacteria that have been subjected to endocytosis to resume free-living vegetative growth. •  The results support the suggestion that bacteroid differentiation into a nitrogen-fixing, organelle-like form, is a gradual process involving several stages, each controlled by different plant genes.