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.

IFITM3 restricts virus-induced inflammatory cytokine production by limiting Nogo-B mediated TLR responses

Interferon-induced transmembrane protein 3 (IFITM3) is a restriction factor that limits viral pathogenesis and exerts poorly understood immunoregulatory functions. Here, using human and mouse models, we demonstrate that IFITM3 promotes MyD88-dependent, TLR-mediated IL-6 production following exposure to cytomegalovirus (CMV). IFITM3 also restricts IL-6 production in response to influenza and SARS-CoV-2. In dendritic cells, IFITM3 binds to the reticulon 4 isoform Nogo-B and promotes its proteasomal degradation. We reveal that Nogo-B mediates TLR-dependent pro-inflammatory cytokine production and promotes viral pathogenesis in vivo, and in the case of TLR2 responses, this process involves alteration of TLR2 cellular localization. Nogo-B deletion abrogates inflammatory cytokine responses and associated disease in virus-infected IFITM3-deficient mice. Thus, we uncover Nogo-B as a driver of viral pathogenesis and highlight an immunoregulatory pathway in which IFITM3 fine-tunes the responsiveness of myeloid cells to viral stimulation.

Digital intervention increases influenza vaccination rates for people with diabetes in a decentralized randomized trial

People with diabetes (PWD) have an increased risk of developing influenza-related complications, including pneumonia, abnormal glycemic events, and hospitalization. Annual influenza vaccination is recommended for PWD, but vaccination rates are suboptimal. The study aimed to increase influenza vaccination rate in people with self-reported diabetes. This study was a prospective, 1:1 randomized controlled trial of a 6-month Digital Diabetes Intervention in U.S. adults with diabetes. The intervention group received monthly messages through an online health platform. The control group received no intervention. Difference in self-reported vaccination rates was tested using multivariable logistic regression controlling for demographics and comorbidities. The study was registered at clinicaltrials.gov: NCT03870997. A total of 10,429 participants reported influenza vaccination status (5158 intervention, mean age (±SD) = 46.8 (11.1), 78.5% female; 5271 control, Mean age (±SD) = 46.7 (11.2), 79.4% female). After a 6-month intervention, 64.2% of the intervention arm reported influenza vaccination, vers us 61.1% in the control arm (diff = 3.1, RR = 1.05, 95% CI [1.02, 1.08], p = 0.0013, number needed to treat = 33 to obtain 1 additional vaccination). Completion of one or more intervention messages was associated with up to an 8% increase in vaccination rate (OR 1.27, 95% CI [1.17, 1.38], p < 0.0001). The intervention improved influenza vaccination rates in PWD, suggesting that leveraging new technology to deliver knowledge and information can improve influenza vaccination rates in high-risk populations to reduce public health burden of influenza. Rapid cycle innovation could maximize the effects of these digital interventions in the future with other populations and vaccines.

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.

Interferon-Induced Transmembrane Protein 1 Restricts Replication of Viruses That Enter Cells via the Plasma Membrane

The acute antiviral response is mediated by a family of interferon-stimulated genes (ISGs), providing cell-intrinsic immunity. Mutations in genes encoding these proteins are often associated with increased susceptibility to viral infections. One family of ISGs with antiviral function is the interferon-inducible transmembrane proteins (IFITMs), of which IFITM3 has been studied extensively. In contrast, IFITM1 has not been studied in detail. Since IFITM1 can localize to the plasma membrane, we investigated its function with a range of enveloped viruses thought to infect cells by fusion with the plasma membrane. Overexpression of IFITM1 prevented infection by a number of Paramyxoviridae and Pneumoviridae, including respiratory syncytial virus (RSV), mumps virus, and human metapneumovirus (HMPV). IFITM1 also restricted infection with an enveloped DNA virus that can enter via the plasma membrane, herpes simplex virus 1 (HSV-1). To test the importance of plasma membrane localization for IFITM1 function, we identified blocks of amino acids in the conserved intracellular loop (CIL) domain that altered the subcellular localization of the protein and reduced antiviral activity. By screening reported data sets, 12 rare nonsynonymous single nucleotide polymorphisms (SNPs) were identified in human IFITM1, some of which are in the CIL domain. Using an Ifitm1-/- mouse, we show that RSV infection was more severe, thereby extending the range of viruses restricted in vivo by IFITM proteins and suggesting overall that IFITM1 is broadly antiviral and that this antiviral function is associated with cell surface localization.IMPORTANCE Host susceptibility to viral infection is multifactorial, but early control of viruses not previously encountered is predominantly mediated by the interferon-stimulated gene (ISG) family. There are upwards of 300 of these genes, the majority of which do not have a clearly defined function or mechanism of action. The cellular location of these proteins may have an important effect on their function. One ISG located at the plasma membrane is interferon-inducible transmembrane protein 1 (IFITM1). Here we demonstrate that IFITM1 can inhibit infection with a range of viruses that enter via the plasma membrane. Mutant IFITM1 proteins that were unable to localize to the plasma membrane did not restrict viral infection. We also observed for the first time that IFITM1 plays a role in vivo, and Ifitm1-/- mice were more susceptible to viral lung infection. These data contribute to our understanding of how ISGs prevent viral infections.

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.

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.

[Severe pneumonia due to cytomegalovirus in chronic obstructive pulmonary disease]

Severe pneumonia due to cytomegalovirus in chronic obstructive pulmonary disease.

INTRODUCTION

We describe two cases of immunocompetent patients with chronic obstructive pulmonary disease (COPD) who developed severe cytomegalovirus (CMV) pneumonia. The clinical and radiological context and CMV replication in broncho-alveolar lavage suggested a diagnosis of CMV pneumonia.

CASE HISTORIES

We report two cases in patients with moderate chronic obstructive pulmonary disease not treated with long-term steroid therapy who developed bilateral pneumonia with hypoxaemia. The only pathogen identified was CMV with replication of the virus in the broncho-alveolar lavage. Investigation failed to detect any associated immune deficiency.

CONCLUSION

Severe cytomegalovirus pneumonia could be encouraged by the existence of chronic obstructive pulmonary disease due to local inflammatory changes.

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.

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.

Current application of National Institute for Health and Clinical Excellence (NICE) guidance in the management of patients with severe psoriasis: a clinical audit against NICE guidance in seven National Health Service specialist dermatology units in England

BACKGROUND

Psoriasis affects 1-2% of the U.K. population, with 20-30% of those affected having severe psoriasis managed with systemic therapies. Biological agents are a useful option when other systemic therapies have failed. The National Institute for Health and Clinical Excellence (NICE) in the U.K. has published three sets of guidance relating to the use of biological agents.

AIM

To establish whether biological agents were being used in line with NICE guidance.

METHODS

The study was conducted in seven specialist dermatology units, and involved the retrospective collection of data from patients treated with biological agents since the introduction of the NICE guidance.

RESULTS

In total, 176 patients with 212 episodes of treatment were included in the study. Biologics were started for appropriately severe disease in 85% of cases (n = 180) and only after failure, intolerance or contraindication to standard systemic therapies in 97% of cases (n = 206). Etanercept was discontinued appropriately in responders before week 24 in only 12% (five of 60 responders). Across all agents, 40% (72 of 178 with continuity status) were continued on treatment despite not achieving an adequate response according to NICE criteria.

CONCLUSIONS

In the seven sites audited, compliance with national guidance was entirely appropriate in terms of therapy initiation; however, the requirement to discontinue etanercept in responders was rarely followed. Similarly, discontinuation of biologicals in nonresponders was not routine practice. This may indicate a reluctance of both patients and clinicians to withdraw an at least partly effective therapy from these refractory patients.

Issues of drinking water quality of small scale water services towards climate change

As climate change could impact water quantity and quality, important concerns are related to water quality degradation in small scale water services (SSWS). SSWS using surface waters resources (rivers and lakes) for drinking water production are particularly vulnerable to short term transient events due to their low adaptation capacity and their lack of support and technical knowledge compared to major centralized systems. Based on weather and water quality databases, a case study was conducted on a SSWS in Brittany (France) pumping from surface water. Results show an important vulnerability in treatment efficiency related to the lowest and highest river flows and provide first assumptions about the impacts of an increase in extreme weather events with climate change on drinking water quality.

Stabilisation of critically ill children at the district general hospital prior to intensive care retrieval: a snapshot of current practice

OBJECTIVE

To describe current practice during stabilisation of children presenting with critical illness to the district general hospital (DGH), preceding retrieval to intensive care.

DESIGN

Observational study using prospectively collected transport data.

SETTING

A centralised intensive care retrieval service in England and referring DGHs.

PATIENTS

Emergency transports to intensive care during 2-month epochs from 4 consecutive years (2005-2008).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Proportion of key airway, breathing, and circulatory and neurological stabilisation procedures, such as endotracheal intubation, mechanical ventilation, vascular access, and initiation of inotropic agents, performed by referring hospital staff prior to the arrival of the retrieval team.

RESULTS

706 emergency retrievals were examined over a 4-year period. The median age of transported children was 10 months (IQR, 18 days to 43 months). DGH staff performed the majority of endotracheal intubations (93.7%, CI 91.3% to 95.5%), initiated mechanical ventilation in 76.9% of cases (CI 73.0% to 80.4%), inserted central venous catheters frequently (67.4%, CI 61.7% to 72.6%), and initiated inotropic agents in 43.7% (CI 36.6% to 51.1%). The retrieval team was more likely to perform interventions such as reintubation for air leak, repositioning of misplaced tracheal tubes, and administration of osmotic agents for raised intracranial pressure. The performance of one or more interventions by the retrieval team was associated with severity of illness, rather than patient age, diagnostic group, or team response time (OR 3.62, 95% CI 1.47 to 8.92).

CONCLUSIONS

DGH staff appropriately performs the majority of initial stabilisation procedures in critically ill children prior to retrieval. This practice has not changed significantly for the past 4 years, attesting to the crucial role played by district hospital staff in a centralised model of paediatric intensive care.

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.

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.

Impacts of climate change on surface water quality in relation to drinking water production

Besides climate change impacts on water availability and hydrological risks, the consequences on water quality is just beginning to be studied. This review aims at proposing a synthesis of the most recent existing interdisciplinary literature on the topic. After a short presentation about the role of the main factors (warming and consequences of extreme events) explaining climate change effects on water quality, the focus will be on two main points. First, the impacts on water quality of resources (rivers and lakes) modifying parameters values (physico-chemical parameters, micropollutants and biological parameters) are considered. Then, the expected impacts on drinking water production and quality of supplied water are discussed. The main conclusion which can be drawn is that a degradation trend of drinking water quality in the context of climate change leads to an increase of at risk situations related to potential health impact.

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.

Eczema-like plaques secondary to enoxaparin

Low-molecular-weight heparins are used extensively in acute medicine. They are generally well tolerated but may cause a rare, eczema-like type IV hypersensitivity reaction. We report 3 cases of this eruption and speculate that it may be significantly under-reported due to misidentifying the causal drug, which may have serious consequences. We discuss treatment alternatives such as fondaparinux sodium, which may rarely cross-react.

Regulation of cyclin D2 and the cyclin D2 promoter by protein kinase A and CREB in lymphocytes

Lymphocyte proliferation is key to the regulation of the immune system. Cyclin D2 is the first cell cycle protein induced following stimulation through the T-cell receptor, the B-cell receptor or cytokines. The promoter of this cyclin integrates a diverse range of signals. Through investigating the regulation of this promoter by interleukin-2 and phosphatidylinositol 3-kinase, we have identified a role for the transcription factor CREB, cAMP response element-binding protein. Mutation of the CREB-binding site reduced cyclin D2 promoter activity 5-10-fold. CREB-1 is phosphorylated at serine 133, a critical site for activity, in both T cells and Epstein-Barr virus immortalized B cells. The introduction of an S133A mutant of CREB-1 reduces IL-2 induction of cyclin D2 promoter activity, demonstrating a role for this phosphorylation site in promoter activity. Two inhibitors of protein kinase A reduce lymphocyte proliferation and CREB-1 phosphorylation. This study demonstrates that the cyclin D2 promoter is capable of being regulated by PI3K and CREB and identifies CREB-1 and protein kinase A as potential targets for altering lymphocyte proliferation.

Identification in 2 Independent Samples of a Novel Schizophrenia RiskHaplotype of the Dystrobrevin Binding Protein Gene (DTNBP1)

CONTEXT

Recent research suggests that variation in the gene encoding dystrobrevin binding protein (DTNBP1) confers susceptibility to schizophrenia. Thus far, no specific risk haplotype has been identified in more than 1 study.

OBJECTIVES

To confirm DTNBP1 as a schizophrenia susceptibility gene, to identify and replicate specific risk and protective haplotypes, and to explore relationships between DTNBP1 and the phenotype.

DESIGN

Genetic association study based on mutation detection and case-control analysis.

SETTING

All subjects were unrelated and ascertained from general (secondary care) psychiatric inpatient and outpatient services.

PARTICIPANTS

The Cardiff, Wales, sample included 708 white subjects from the United Kingdom and Ireland (221 females) who met DSM-IV criteria for schizophrenia and were individually matched for age, sex, and ethnicity to 711 blood donor controls (233 females). Mean +/- SD age at first psychiatric contact for cases was 23.6 +/- 7.7 years; mean age at ascertainment was 41.8 +/- 13.5 years. The Dublin, Ireland, sample included 219 white subjects from the Republic of Ireland who met DSM-III-R criteria for schizophrenia or schizoaffective disorder and 231 controls. The mean age of the Irish cases was 46.0 +/- 8.5 years; mean age at first psychiatric contact was 25.2 +/- 12.4 years.

MAIN OUTCOME MEASURE

Evidence for association between the DTNBP1 locus and schizophrenia.

RESULTS

In the Cardiff sample, there was no evidence for association with previously implicated haplotypes but strong evidence for association with multiple novel haplotypes. Maximum evidence was found for a novel 3-marker haplotype (global P<.001), composed of 1 risk haplotype (P =.01) and 2 protective haplotypes, 1 common (P =.006) and 1 rare (P<.001). Specific risk and protective haplotypes were replicated in the Dublin sample (P =.02,.047, and.006, respectively). The only phenotypic variable associated with any haplotype was between the common protective haplotype and higher educational achievement (P =.02, corrected for multiple tests).

CONCLUSIONS

DTNBP1 is a susceptibility gene for schizophrenia. Specific risk and protective haplotypes were identified and replicated. Association with educational achievement may suggest protection mediated by IQ, although this needs to be confirmed in an independent data set.

SAW characteristics of AlN films sputtered on silicon substrates

This article is focused on the analysis of the electroacoustic response of surface acoustic wave (SAW) filters made of aluminium nitride (AlN) thin films on various types of Si wafers. AlN films with (00.2) orientation were deposited by RF reactive sputtering of an Al target in Ar and N(2) admixtures on Si(100) and (111) wafers with resistivities ranging between 10 and 2000 Omega cm. The electroacoustic response of SAW filters with an acoustic wavelength of 40 microm was analysed by measuring the Sij parameters with a network analyser. We have determined that the out-of-band loss is directly related to the Si substrate resistivity, varying from 26 dB for 10 Omega cm to 55 dB for 2000 Omega cm. The SAW velocity depends on the orientation of the Si wafer, being approximately 4700 m/s for Si(111) and 5100 m/s for Si(100). The electroacoustic responses of the SAW filters were fitted by computations based on a simple circuital model that takes into account parasitic effects such as airborne electromagnetic coupling and conduction through the substrate. This procedure provides accurate values of the electromechanical coupling factor k2 even for devices with poor characteristics. Good quality SAW filters of AlN on high resistivity Si(100) wafers with k2 larger than 0.12% are demonstrated.

Effect of particle bombardment on the orientation and the residual stress of sputtered AlN films for SAW devices

We present a study of the effect of particle bombardment on the preferred orientation and the residual stress of polycrystalline aluminum nitride (AlN) thin films for surface acoustic wave (SAW) applications. Films were deposited on silicon (100) substrates by radio frequency (RF) sputtering of an aluminum target in an argon and nitrogen gas mixture. The main deposition parameters were changed as follows: the total pressure from 4 mTorr to 11 mTorr, the N2 content in the gas mixture from 20% to 80%, and the substrate self-bias voltage from -10 V to -30 V. If a sufficiently high negative substrate self-bias voltage is induced, (00.2)-oriented films are obtained over the full ranges of pressure and N2 content. Such films have values of residual stress ranging from -3 GPa to +1 GPa, depending on the deposition conditions. Our results suggest that the energy of the Ar ions colliding with the substrate controls the preferred orientation of the films, whereas the directionality of the ions (for the same energy) is the main factor determining the residual stress. To demonstrate the suitability of our material for the intended application, SAW filters with good electroacoustic response have been fabricated using AlN thin films with optimized (00.2) orientation and controlled residual stress.

The effects of temperature and time on thermal bond strength in tendons

Flexor tendon injuries are a common problem requiring sutured repair followed by early postoperative mobilisation. Results are better if active rather than passive flexion is allowed, however active movement increases the incidence of dehiscence. This has prompted examination of thermal bonding as a strategy for strengthening tendon repairs. Three experiments are described, using method and experimental design similar to those previously described. The strength of thermal bonds created between sections of bovine Achilles tendon at a range of temperatures and times was measured. Bonds were created by heating compressed sections in a water bath. Bond strength was measured on a tensiometer as load (N) and stress (N/mm2 and N m kg-1) then calculated using measured cross-sectional area, weight and length. Results were in broad agreement with those previously described, showing peak bond strength in samples heated to 62 degrees C for 8 min (median 17.11 N/cm2, SD 2.13). The effects of cooling to 0 degree C for 10 min immediately after bonding was to increase median bond strength when compared with non-cooled samples bonded under similar conditions (non-cooled, 9.11 N/cm2, SD 3.11; cooled, 11.96 N/cm2, SD 2.93). Statistical analysis using a quadratic regression model showed a close correlation between experimental data and curves modelled to best fit the data. Peak values for thermal bonds created using the methods described approached and in some cases exceeded that reported for the epitendinous element of modified Kessler tendon repairs in human digital flexor tendons. If such bonds could be created in vivo, thermal bonding may have a role in augmenting the strength of tendon repairs. The methods described are impractical for a non-laboratory environment. A laser would seem the most attractive alternative source of heat energy.