Graphene-Based Sensors for the Detection of Bioactive Compounds: A Review

Over the last years, different nanomaterials have been investigated to design highly selective and sensitive sensors, reaching nano/picomolar concentrations of biomolecules, which is crucial for medical sciences and the healthcare industry in order to assess physiological and metabolic parameters. The discovery of graphene (G) has unexpectedly impulsed research on developing cost-effective electrode materials owed to its unique physical and chemical properties, including high specific surface area, elevated carrier mobility, exceptional electrical and thermal conductivity, strong stiffness and strength combined with flexibility and optical transparency. G and its derivatives, including graphene oxide (GO) and reduced graphene oxide (rGO), are becoming an important class of nanomaterials in the area of optical and electrochemical sensors. The presence of oxygenated functional groups makes GO nanosheets amphiphilic, facilitating chemical functionalization. G-based nanomaterials can be easily combined with different types of inorganic nanoparticles, including metals and metal oxides, quantum dots, organic polymers, and biomolecules, to yield a wide range of nanocomposites with enhanced sensitivity for sensor applications. This review provides an overview of recent research on G-based nanocomposites for the detection of bioactive compounds, providing insights on the unique advantages offered by G and its derivatives. Their synthesis process, functionalization routes, and main properties are summarized, and the main challenges are also discussed. The antioxidants selected for this review are melatonin, gallic acid, tannic acid, resveratrol, oleuropein, hydroxytyrosol, tocopherol, ascorbic acid, and curcumin. They were chosen owed to their beneficial properties for human health, including antibiotic, antiviral, cardiovascular protector, anticancer, anti-inflammatory, cytoprotective, neuroprotective, antiageing, antidegenerative, and antiallergic capacity. The sensitivity and selectivity of G-based electrochemical and fluorescent sensors are also examined. Finally, the future outlook for the development of G-based sensors for this type of biocompounds is outlined

Graphene Oxides Derivatives Prepared by an Electrochemical Approach: Correlation between Structure and Properties

Graphene oxide (GO) can be defined as a single monolayer of graphite with oxygen-containing functionalities such as epoxides, alcohols, and carboxylic acids. It is an interesting alternative to graphene for many applications due to its exceptional properties and feasibility of functionalization. In this study, electrochemically exfoliated graphene oxides (EGOs) with different amounts of surface groups, hence level of oxidation, were prepared by an electrochemical two-stage approach using graphite as raw material. A complete characterization of the EGOs was carried out in order to correlate their surface topography, interlayer spacing, defect content, and specific surface area (SSA) with their electrical, thermal, and mechanical properties. It has been found that the SSA has a direct relationship with the d-spacing. The EGOs electrical resistance decreases with increasing SSA while rises with increasing the D/G band intensity ratio in the Raman spectra, hence the defect content. Their thermal stability under both nitrogen and dry air atmospheres depends on both their oxidation level and defect content. Their macroscopic mechanical properties, namely the Young's modulus and tensile strength, are influenced by the defect content, while no correlation was found with their SSA or interlayer spacing. Young moduli values as high as 54 GPa have been measured, which corroborates that the developed method preserves the integrity of the graphene flakes. Understanding the structure-property relationships in these materials is useful for the design of modified GOs with controllable morphologies and properties for a wide range of applications in electrical/electronic devices

Tailorable synthesis of highly oxidized graphene oxides via an environmentally friendly electrochemical process

Graphene oxide (GO) is an attractive alternative to graphene for many applications due to its captivating optical, chemical, and electrical characteristics. In this work, GO powders with a different amount of surface groups were synthesized from graphite via an electrochemical two-stage process. Many synthesis conditions were tried to maximize the oxidation level, and comprehensive characterization of the resulting samples was carried out via elemental analysis, microscopies (TEM, SEM, AFM), X-ray diffraction, FT-IR and Raman spectroscopies as well as electrical resistance measurements. SEM and TEM images corroborate that the electrochemical process used herein preserves the integrity of the graphene flakes, enabling to obtain large, uniform and well exfoliated GO sheets. The GOs display a wide range of C/O ratios, determined by the voltage and time of each stage as well as the electrolyte concentration, and an unprecedented minimum C/O value was obtained for the optimal conditions. FT-IR evidences strong intermolecular interactions between neighbouring oxygenated groups. The intensity ratio of D/G bands in the Raman spectra is high for samples prepared using concentrated H2SO4 as an electrolyte, indicative of many defects. Furthermore, these GOs exhibit smaller interlayer spacing than that expected according to their oxygen content, which suggests predominant oxidation on the flake edges. Results point out that the electrical resistance is conditioned mostly by the interlayer distance and not simply by the C/O ratio. The tuning of the oxidation level is useful for the design of GOs with tailorable structural, electrical, optical, mechanical, and thermal properties.Ministerio de Ciencia, Innovacion y Universidade

Advanced displays and natural user interfaces to support learning

[EN] Advanced displays and Natural User Interfaces (NUI) are a very suitable combination for developing systems to provide an enhanced and richer user experience. This combination can be appropriate in several fields and has not been extensively exploited. One of the fields that this combination is especially suitable for is education. Nowadays, children are growing up playing with computer games, using mobile devices, and other technological devices. New learning methods that use these new technologies can help in the learning process. In this paper, two new methods that use advanced displays and NUI for learning about a period of history are presented. One of the methods is an autostereoscopic system that lets children see themselves as a background in the game and renders the elements in 3D without the need for special glasses; the second method is a frontal projection system that projects the image on a table in 2D and works similarly to a touch table. The Microsoft Kinect© is used in both systems for the interaction. A comparative study to check different aspects was carried out. A total of 128 children from 7 to 11 years old participated in the study. From the results, we observed that the different characteristics of the systems did not influence the children s acquired knowledge, engagement, or satisfaction. There were statistically significant differences for depth perception and presence in which the autostereoscopic system was scored higher. However, of the two systems, the children considered the frontal projection to be easier to use. We would like to highlight that the scores for the two systems and for all the questions were very high. These results suggest that games of this kind (advanced displays and NUI) could be appropriate educational games and that autostereoscopy is a technology to exploit in their development.This work was funded by the Spanish Ministry of Science and Innovation through the APRENDRA project (TIN2009-14319-C02-01).Martín San José, JF.; Juan, M.; Mollá Vayá, RP.; Vivó Hernando, RA. (2017). Advanced displays and natural user interfaces to support learning. Interactive Learning Environments. https://doi.org/10.1080/10494820.2015.1090455

Rapid thawing increases the fragility of the cryopreserved arterial wall

To extend present knowledge of the biomechanical and structural changes which occur in the cryopreserved, rapidly thawed arterial wall. Minipig iliac arterial segments were cryopreserved at -196 degrees C in either minimum essential medium or Wisconsin solution. Fresh segments served as the control group. After 1 month, the specimens were rapidly thawed (37 degrees C) and processed for biomechanical, ultrastructural, morphological and immunohistochemical (MMP-1, MMP-2, MMP-3 and MMP-9) analysis. Visualisation of apoptotic cells was performed by TUNEL method. For the mechanical distension analysis, an in vitro circuit was designed. The cryopreserved segments showed a 42% incidence of spontaneous fracture and the appearance of microfractures which affected the endoluminal third of the vessel. An accumulation of liquid in the subelastica was observed. An increased expression of wall-degradative enzymes (mainly MMP-2) was also observed following cryopreservation. No significant differences were detected in the proportional elasticity module or tensile strength of the specimen groups. No differences in mechanical distension were observed between groups after the vessel segments were subjected to the pulsatile circuit flow for 72 h. Cell damage was most intense in the specimens cryopreserved in Wisconsin solution. Cryopreservation in both the solutions employed, followed by rapid thawing, induce changes in the permeability which increase the fragility of the cryopreserved arterial wall. Both increased expression of wall-degradative enzymes and accumulation of liquid may contribute to graft failure after implantation

Shared decision making with schizophrenic patients: a randomized controlled clinical trial with booster sessions (DECIDE Study)

Background: The treatment of schizophrenia requires a prolonged, multidimensional intervention that includes antipsychotic drugs. Treatment adherence is essential to effectively control the disorder. Shared decision-making (SDM) is a strategy, supported by numerous practical and ethical arguments, that seeks to involve patients in the therapeutic process to improve treatment adherence and satisfaction. The use of this model in mental health has been limited for many intrinsic and extrinsic reasons. The results of clinical trials conducted to date have largely been disappointing, potential due to study design-related limitations. Aim/Question: To evaluate the efficacy, in terms of treatment adherence and improvement in clinical variables, such as severity of symptoms, days of hospitalization or insight, of a carefully timed SDM model initiated immediately prior to hospital discharge in patients with schizophrenia. Methods: Single-blind, randomized clinical trial in an acute psychiatric care unit within the Andalusian Health Department to compare SDM (experimental group) to treatment as usual (TAU; control group) in a sample of patients hospitalized for an acute episode of schizophrenia or schizoaffective disorder. The study was performed between January 2014 and June 2017. The experimental group participated in SDM sessions prior to discharge with regular booster sessions over the one-year follow-up. The health care team responsible for SDM was predisposed to concordance (LatCon II scale) and received specific training in SDM. A hierarchical multiple linear regression analysis was performed to evaluate the factors independently associated with adherence, controlling for sociodemographic, clinical, and admission-related variables. Variables were assessed at admission, discharge and at 3, 6 and 12 months after discharge during the one year follow up. BARS, DAI, WAI-S, COMRADE and PANSS were used to evaluate adherence, attitude to treatment, therapeutic alliance, satisfaction and confidence with decision and clinical status, respectively. Results: A total of 227 schizophrenic patients hospitalized with acute decompensation were evaluated; of these, 102 met all inclusion criteria and were included in the study. Most patients (95%) had prior experience with antipsychotics and most (82%) had experienced related side effects. Despite randomization, psychopathologic severity was greater in the experimental group, with a mean (SD) PANSS score of 104.08 (80) vs. 93.45 (20.30) (p < 0.05). The final regression model to explain adherence was significant (adjusted R2 = 0.384; F [df= 6] = 4.386; p < 0.001), with a direct, significant and independent association with SDM mediated by the number of booster sessions. Discussion: Shared decision making with booster sessions appears to increase treatment adherence in patients with severe mental disorders. Implication on practice: Ethical, practical, and clinical reasons support the use of strategies designed promote the use of long-term, shared decision-making in psychiatric patients, especially in schizophrenia spectrum disorder. Background: Adherence is essential for the successful treatment of schizophrenia. Shared decision making is a strategy that aims to involve patients in the treatment process to improve satisfaction with treatment. However, the evidence to support this approach remains inconclusive. Aim/Question: To assess the efficacy, in terms of treatment adherence and clinical variables, of a shared decision-making approach initiated immediately prior to hospital discharge and at regular intervals during one-year follow-up in patients with schizophrenia. Methods: Single-blind randomized clinical trial with in an acute psychiatric care unit within the Andalusian Health Department, with booster sessions at months 3, 6, and 12 during the follow-up. A hierarchical multiple linear regression was performed to assess adherence, controlling for sociodemographic, clinical, and admission-related variables, and the application or not of shared decision-making. Results: 102 patients with acute decompensation were included. Despite randomization, psychopathologic severity was greater in the experimental group, with a mean (SD) PANSS score of 104.08 (80) vs. 93.45 (20.30) (p < 0.05). The final explanatory adherence model was significant (adjusted R2 = 0.384; F [df = 16] = 4.386; p < 0.001), with a significant and independent association of shared decision-making mediated by the number of booster sessions applied. Conclusions: The application of shared decision making with booster sessions appears to increase the likelihood of treatment adherence in schizophrenia spectrum disorder. © 2023 The Author

Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip

Background: Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods: We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction (LVEF), functional mitral regurgitation (FMR) grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results: Ninety-three patients (68.2+/-10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-month follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0+/-17.8 vs. 2.7+/-13.5, P=0.002), sustained VT or ventricular fibrillation (0.9+/-2.5 vs. 0.5+/-2.9, P=0.012) and ICD antitachycardia therapies (2.5+/-12.0 vs. 0.9+/-5.0, P=0.033) were observed. Conclusions: PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort

Positioning systems in Minkowski space-time: from emission to inertial coordinates

The coordinate transformation between emission coordinates and inertial coordinates in Minkowski space-time is obtained for arbitrary configurations of the emitters. It appears that a positioning system always generates two different coordinate domains, namely, the front and the back emission coordinate domains. For both domains, the corresponding covariant expression of the transformation is explicitly given in terms of the emitter world-lines. This task requires the notion of orientation of an emitter configuration. The orientation is shown to be computable from the emission coordinates for the users of a `central' region of the front emission coordinate domain. Other space-time regions associated with the emission coordinates are also outlined.Comment: 20 pages; 1 figur

Music-related activities on Facebook

Despite the current prevalence of users performing musical activities on social media, and on Facebook in particular, little research has examined these behaviors from the perspective of consumer psychology. A cross-sectional, convenience sample of 400 participants (Mage = 22.56, SDage = 7.79) completed an online questionnaire. The findings illustrated that the constructs of opinion leadership, innovativeness, and self-efficacy within the consumer psychology literature were associated with performing music-related activities on Facebook, including the active creation/consumption of music content and use of music listening applications. Thus, music activities performed on Facebook have an overt consumer psychological component. These findings indicate that to understand music-related activities on social media, further research should consider psychological variables in explaining this common and economically important activity

Outcomes in patients with gunshot wounds to the brain.

Introduction:Gunshot wounds to the brain (GSWB) confer high lethality and uncertain recovery. It is unclear which patients benefit from aggressive resuscitation, and furthermore whether patients with GSWB undergoing cardiopulmonary resuscitation (CPR) have potential for survival or organ donation. Therefore, we sought to determine the rates of survival and organ donation, as well as identify factors associated with both outcomes in patients with GSWB undergoing CPR. Methods:We performed a retrospective, multicenter study at 25 US trauma centers including dates between June 1, 2011 and December 31, 2017. Patients were included if they suffered isolated GSWB and required CPR at a referring hospital, in the field, or in the trauma resuscitation room. Patients were excluded for significant torso or extremity injuries, or if pregnant. Binomial regression models were used to determine predictors of survival/organ donation. Results:825 patients met study criteria; the majority were male (87.6%) with a mean age of 36.5 years. Most (67%) underwent CPR in the field and 2.1% (n=17) survived to discharge. Of the non-survivors, 17.5% (n=141) were considered eligible donors, with a donation rate of 58.9% (n=83) in this group. Regression models found several predictors of survival. Hormone replacement was predictive of both survival and organ donation. Conclusion:We found that GSWB requiring CPR during trauma resuscitation was associated with a 2.1% survival rate and overall organ donation rate of 10.3%. Several factors appear to be favorably associated with survival, although predictions are uncertain due to the low number of survivors in this patient population. Hormone replacement was predictive of both survival and organ donation. These results are a starting point for determining appropriate treatment algorithms for this devastating clinical condition. Level of evidence:Level II