Relationship between oxygen supply and cerebral blood flow assessed by transcranial Doppler and near – infrared spectroscopy in healthy subjects during breath – holding

BACKGROUND: Breath – holding (BH) is a suitable method for inducing cerebral vasomotor reactivity (VMR). The assessment of VMR is of clinical importance for the early detection of risk conditions and for the follow-up of disabled patients. Transcranial Doppler ultrasonography (TCD) is used to measure cerebral blood flow velocity (CBFV) during BH, whereas near-infrared spectroscopy (NIRS) measures the concentrations of the oxygenated (O(2)Hb) and reduced (CO(2)Hb) hemoglobin. The two techniques provide circulatory and functional-related parameters. The aim of the study is the analysis of the relationship between oxygen supply and CBFV as detected by TCD and NIRS in healthy subjects performing BH. METHODS: 20 healthy subjects (15 males and 5 females, age 33 ± 4.5 years) underwent TCD and NIRS examination during voluntary breath – holding. VMR was quantified by means of the breath-holding index (BHI). We evaluated the BHI based on mean CBFV, O(2)Hb and CO(2)Hb concentrations, relating the baseline to post-stimulus values. To quantify VMR we also computed the slope of the linear regression line of the concentration signals during BH. From the NIRS signals we also derived the bidimensional representation of VMR, plotting the instantaneous O(2)Hb concentration vs the CO(2)Hb concentration during the BH phase. Two subjects, a 30 years old current smoker female and a 63 years old male with a ischemic stroke event at the left middle cerebral artery, were tested as case studies. RESULTS: The BHI for the CBFV was equal to 1.28 ± 0.71 %/s, the BHI for the O(2)Hb to 0.055 ± 0.037 μmol/l/s and the BHI for CO(2)Hb to 0.0006 ± 0.0019 μmol/l/s, the O(2)Hb slope was equal to 0.15 ± 0.09 μmol/l/s and the CO(2)Hb slope to 0.09 ± 0.04 μmol/l/s. There was a positive correlation between the CBFV and the O(2)Hb increments during BH (r = 0.865). The bidimensional VMR pattern shows common features among healthy subjects that are lost in the control studies. CONCLUSION: We show that healthy subjects present a common VMR pattern when counteracting cerebral blood flow perturbations induced by voluntary BH. The proposed methodology allows for the monitoring of changes in the VMR pattern, hence it could be used for assessing the efficacy of neurorehabilitation protocols

Recent Advances in Seeded and Seed-Layer-Free Atomic Layer Deposition of High-K Dielectrics on Graphene for Electronics

Graphene (Gr) with its distinctive features is the most studied two-dimensional (2D) material for the new generation of high frequency and optoelectronic devices. In this context, the Atomic Layer Deposition (ALD) of ultra-thin high-k insulators on Gr is essential for the implementation of many electronic devices. However, the lack of out-of-plane bonds in the sp2 lattice of Gr typically hinders the direct ALD growth on its surface. To date, several pre-functionalization and/or seed-layer deposition processes have been explored, to promote the ALD nucleation on Gr. The main challenge of these approaches is achieving ultra-thin insulators with nearly ideal dielectric properties (permittivity, breakdown field), while preserving the structural and electronic properties of Gr. This paper will review recent developments of ALD of high k-dielectrics, in particular Al2O3, on Gr with "in-situ" seed-layer approaches. Furthermore, recent reports on seed-layer-free ALD onto epitaxial Gr on SiC and onto Gr grown by chemical vapor deposition (CVD) on metals will be presented, discussing the role played by Gr interaction with the underlying substrates

Nanostructures for SERS in living cell

Surface-enhanced Raman spectroscopy (SERS) has received renewed interest in recent years in fields such as trace analysis, biorelated diagnosis, and living cell study. However, the interference of impurities left on the surface from the preparation process of substrates limits to some extent the application of SERS. In the present paper, we propose a method to prepare clean SERS substrates by a combined method of hydrothermal green synthesis and thermal treatment to obtain a clean and impurity-free surface for SERS measurements, suitable for cells growth. The goal of such activity was the study of the membrane proteome, with special attention to prion protein (PrPC), in its physiological ambient. SERS has been used to evidence the PrPC-Cu(II) interaction in a rat neuroblastoma cell line (B104), known to overexpress the cellular prion protein PrPC

Chondral injuries in patients with recurrent patellar dislocation: a systematic review

Background Patellar dislocations in patients presenting with recurrent patellofemoral instability can damage the surrounding structures, limiting patient's participation to recreational activities and quality of life. This study evaluated frequency, location, and extent of associated injuries in patients with recurrent patellar dislocation. Methods This systematic review was conducted according to the PRISMA checklist. PubMed, Google scholar, Embase, and Web of Science databases were accessed in July 2021. All the published clinical studies reporting frequency, location, and extent of soft tissue lesions in patients with recurrent patellar dislocations were accessed. Results Data from 9 articles (232 patients) were retrieved. The mean age of the included patients was 21.2 +/- 5.6 years. 84.8% of patients suffering from recurrent patellar dislocations demonstrated patellar chondral defects: medial facet (34.9%), while patellar crest (34.8%) and lateral facet (17%). 27.8% of patients demonstrated trochlear chondral injuries. Conclusion Chondral defects of the medial facet and the crest of the patella are the most common in patients with recurrent patellofemoral instability

Chondral and Soft Tissue Injuries Associated to Acute Patellar Dislocation: A Systematic Review

Introduction: Chondral and soft tissue injuries can be associated with first time patellar dislocation, but it is unclear how common they are, and which tissues are affected. A systematic review of the literature was performed to investigate the frequency, location, and extent of chondral and medial patellofemoral ligament (MPFL) injuries in patients following first time patellar dislocation. Methods: This systematic review was conducted according to the PRISMA guidelines. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in November 2021. All the published clinical studies reporting the frequency, location, and extent of soft tissue lesions following first time patellar dislocation were accessed. Studies reporting data on habitual, congenital, or recurrent patellofemoral instability were excluded. Results: Data from 42 articles (2254 patients, mean age 21.6 +/- 7.3 years) were retrieved. Ninety-eight percent of patients who experienced first time patellar dislocation demonstrated MPFL rupture at MRI. Forty-eight percent of MPFL ruptures were located at the patellar side, 34% at the femoral insertion site, and 18% in the midportion. Eighty-five percent of patients showed signs of patellar chondral damage at MRI, and trochlear chondral injuries were evidenced in 47% of patients. Intra-articular loose bodies were observed in 11.5% of patients. At arthroscopy, the medial facet and the crest of the patella more commonly exhibited chondral lesions than the lateral facet and femoral trochlea. Conclusions: Most patients suffer chondral damage and MPFL tears following after a first time patellar dislocation

italian early adolescent females intrinsic motivation in sport an explorative study of psychological and sociorelational correlates

Abstract Using self-determination theory (SDT), this study simultaneously investigated the relationships between intrinsic motivation, psychological factors (sport enjoyment, social self-efficacy), and sociorelational factors (perceived coaching behaviors) by subsequently testing whether psychological factors mediate the relationships between social-relational factors and intrinsic motivation. One hundred and twentyseven early adolescent females from several teams of the Italian Volleyball Society completed a self-report questionnaire. Results showed that female athletes' intrinsic motivation was associated with a) sport enjoyment and b) perceived coaching behaviors (e.g., training and instruction, social support). Second, results showed that training-and-instruction coaches' leadership style affected intrinsic motivation via the females' enjoyment in sport. This study provided further insights into unknown associations among psychological, sociorelational factors and intrinsic motivation, highlighting the innovative role of sport enjoyment as a key factor for sustaining intrinsic motivation. Original and useful behavioral suggestions will be given to the coaches in order to sustain female athletes' sport enjoyment and their intrinsic motivation