Frequency-shift vs phase-shift characterization of in-liquid quartz crystal microbalance applications

The improvement of sensitivity in quartz crystal microbalance (QCM) applications has been addressed in the last decades by increasing the sensor fundamental frequency, following the increment of the frequencymass sensitivity with the square of frequency predicted by Sauerbrey. However, this sensitivity improvement has not been completely transferred in terms of resolution. The decrease of frequency stability due to the increase of the phase noise, particularly in oscillators, made impossible to reach the expected resolution. A new concept of sensor characterization at constant frequency has been recently proposed. The validation of the new concept is presented in this work. An immunosensor application for the detection of a low molecular weight contaminant, the insecticide carbaryl, has been chosen for the validation. An, in principle, improved version of a balanced-bridge oscillator is validated for its use in liquids, and applied for the frequency shift characterization of the QCM immunosensor application. The classical frequency shift characterization is compared with the new phase-shift characterization concept and system proposed. © 2011 American Institute of Physics.The authors are grateful to the Spanish Ministry of Science and Technology for the financial support to this research under contract reference AGL2009-13511, and to the company Advanced Wave Sensors S. L. (www.awsensors.com) for the help provided in the development of some parts of this work.Montagut Ferizzola, YJ.; García Narbón, JV.; Jiménez Jiménez, Y.; March Iborra, MDC.; Montoya Baides, Á.; Arnau Vives, A. (2011). Frequency-shift vs phase-shift characterization of in-liquid quartz crystal microbalance applications. Review of Scientific Instruments. 82(6):1-14. https://doi.org/10.1063/1.3598340S114826Sauerbrey, G. (1959). 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Patients' views and experiences of live supervised tele-exercise classes following bariatric surgery during the COVID-19 pandemic: The BARI-LIFESTYLE qualitative study

The BARI-LIFESTYLE trial is a randomized controlled trial evaluating the efficacy of a post-surgery nutritional and behavioural tele-counselling, and supervised exercise programme to maximize the health benefits of bariatric surgery. Due to the coronavirus disease 2019 (COVID-19) pandemic, the in-person supervised exercise component had to be converted to remote tele-exercise. However, patients' acceptability of this method of exercise provision is unknown. Between 3 and 6 months following bariatric surgery, 13 adults participated in weekly, structured, 60-min supervised exercise classes delivered via Zoom by a trained exercise therapist. A total of 12 participants (n = 8 female), with a mean age of 46.3 (range 33–63) years, who had undergone either sleeve gastrectomy (n = 8) or Roux-en-Y gastric bypass (n = 4) surgery, participated in one-to-one semi-structured interviews following the tele-exercise classes. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis. Participants described how the tele-exercise classes helped them to cope with the changes to their lives brought about by the COVID-19 pandemic. Participants found the tele-exercise schedule, content and intensity to be acceptable, and were satisfied with the privacy, security and safety of the technology and classes. Professional supervision and guidance from an exercise therapist were described as central to the tele-exercise provision. Importantly, participation in the tele-exercise provided physical, emotional and social benefits. Few participants reported barriers to participation. Overall, the tele-exercise classes were deemed acceptable and compared favourably to in-person exercise classes

Multifocal Transcranial Direct Current Stimulation in Primary Progressive Aphasia Does Not Provide a Clinical Benefit Over Speech Therapy

Primary progressive aphasia (PPA) is a group of neurodegenerative disorders including Alzheimer's disease and frontotemporal dementia characterized by language deterioration. Transcranial direct current stimulation (tDCS) is a non-invasive intervention for brain dysfunction.To evaluate the tolerability and efficacy of tDCS combined with speech therapy in the three variants of PPA. We evaluate changes in fMRI activity in a subset of patients.Double-blinded, randomized, cross-over, and sham-controlled tDCS study. 15 patients with PPA were included. Each patient underwent two interventions: a) speech therapy + active tDCS and b) speech therapy + sham tDCS stimulation. A multifocal strategy with anodes placed in the left frontal and parietal regions was used to stimulate the entire language network. Efficacy was evaluated by comparing the results of two independent sets of neuropsychological assessments administered at baseline, immediately after the intervention, and at 1 month and 3 months after the intervention. In a subsample, fMRI scanning was performed before and after each intervention.The interventions were well tolerated. Participants in both arms showed clinical improvement, but no differences were found between active and sham tDCS interventions in any of the evaluations. There were trends toward better outcomes in the active tDCS group for semantic association and reading skills. fMRI identified an activity increase in the right frontal medial cortex and the bilateral paracingulate gyrus after the active tDCS intervention.We did not find differences between active and sham tDCS stimulation in clinical scores of language function in PPA patients

Nocardia Astéroïdes

Les auteurs décrivent la présence de l'infection à Nocardia astéroïdes en France, chez la vache laitière, à localisation mammaire, plus particu lièrement. Mais d’autres espèces peuvent être touchées. Les mammites sont rebelles à tous traitements et le pronostic économique de l'animal est sombre. L’affection touche les animaux plus particulièrement en pic de lactation. 31 foyers ont été dénombrés du printemps 1982 à l'automne 1983 dans plusieurs départements de France. 55 souches ont été étudiées. Ils soulignent les possibilités de transmission à l'homme et souhaitent une recherche systématique de ce germe dans les laboratoires.The authors described the infection for Nocardia asteroides particulary in the mastitis of cows in French, but other species may be ill. 55 strains of Nocardia asteroides are isolated from 31 outbreaks of infections, during the years 1982-1983. This germ is very antibiotic resistant. They emphasize the possibility of transmission to man and wish systematical research of this germ in the laboratories

GITR Activation Induces an Opposite Effect on Alloreactive CD4+ and CD8+ T Cells in Graft-Versus-Host Disease

Glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) is a member of the tumor necrosis factor receptor (TNFR) family that is expressed at low levels on unstimulated T cells, B cells, and macrophages. Upon activation, CD4+ and CD8+ T cells up-regulate GITR expression, whereas immunoregulatory T cells constitutively express high levels of GITR. Here, we show that GITR may regulate alloreactive responses during graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). Using a BMT model with major histocompatibility complex class I and class II disparity, we demonstrate that GITR stimulation in vitro and in vivo enhances alloreactive CD8+CD25− T cell proliferation, whereas it decreases alloreactive CD4+CD25− proliferation. Allo-stimulated CD4+CD25− cells show increased apoptosis upon GITR stimulation that is dependent on the Fas–FasL pathway. Recipients of an allograft containing CD8+CD25− donor T cells had increased GVHD morbidity and mortality in the presence of GITR-activating antibody (Ab). Conversely, recipients of an allograft with CD4+CD25− T cells showed a significant decrease in GVHD when treated with a GITR-activating Ab. Our findings indicate that GITR has opposite effects on the regulation of alloreactive CD4+ and CD8+ T cells

High-frequency phase shift measurement greatly enhances the sensitivity of QCM immunosensors

[EN] In spite of being widely used for in liquid biosensing applications, sensitivity improvement of conventional (5-20 MHz) quartz crystal microbalance (QCM) sensors remains an unsolved challenging task. With the help of a new electronic characterization approach based on phase change measurements at a constant fixed frequency, a highly sensitive and versatile high fundamental frequency (HFF) QCM immunosensor has successfully been developed and tested for its use in pesticide (carbaryl and thiabendazole) analysis. The analytical performance of several immunosensors was compared in competitive immunoassays taking carbaryl insecticide as the model analyte. The highest sensitivity was exhibited by the 100 MHz HFF-QCM carbaryl immunosensor. When results were compared with those reported for 9 MHz QCM, analytical parameters clearly showed an improvement of one order of magnitude for sensitivity (estimated as the I50 value) and two orders of magnitude for the limit of detection (LOD): 30 µg L-1 vs 0.66 µg L-1 I50 value and 11 µg L-1 vs 0.14 µg L-1 LOD, for 9 and 100 MHz, respectively. For the fungicide thiabendazole, I50 value was roughly the same as that previously reported for SPR under the same biochemical conditions, whereas LOD improved by a factor of 2. The analytical performance achieved by high frequency QCM immunosensors surpassed those of conventional QCM and SPR, closely approaching the most sensitive ELISAs. The developed 100 MHz QCM immunosensor strongly improves sensitivity in biosensing, and therefore can be considered as a very promising new analytical tool for in liquid applications where highly sensitive detection is required.We would like to acknowledge Federico Martin and Juan Antonio Buitrago for their excellent technical assistance. This work was supported by the Spanish Ministry of Economy and Competitiveness/European Regional Development Fund (ERDF) (DETECTA IPT-2012-0154-300000 project).March Iborra, MDC.; García Narbón, JV.; Sánchez, Á.; Arnau Vives, A.; Jiménez Jiménez, Y.; García, P.; Manclus Ciscar, JJ.... (2015). High-frequency phase shift measurement greatly enhances the sensitivity of QCM immunosensors. Biosensors and Bioelectronics. (65):1-8. https://doi.org/10.1016/j.bios.2014.10.001S186