Enhanced optical magnetism for reversed optical binding forces between silicon nanoparticles in the visible region.

We perform a comprehensive numerical analysis on the optical binding forces of a multiple-resonant silicon nanodimer induced by the normal illumination of a plane wave in the visible region. The silicon nanodimer provides either repulsive or attractive forces in water while providing only attractive forces in air. The enhancement of the magnetic dipole mode is attributed to the generation of repulsive forces. The sign (attractive/repulsive) and the amplitude of the optical forces are controlled by incident polarization and separation distance between the silicon nanoparticles. These optomechanical effects demonstrate a key step toward the optical sorting and assembly of silicon nanoparticles.

Kinematic Analysis of Human Gait in Healthy Young Adults Using IMU Sensors: Exploring Relevant Machine Learning Features for Clinical Applications.

BACKGROUND: Gait is the manner or style of walking, involving motor control and coordination to adapt to the surrounding environment. Knowing the kinesthetic markers of normal gait is essential for the diagnosis of certain pathologies or the generation of intelligent ortho-prostheses for the treatment or prevention of gait disorders. The aim of the present study was to identify the key features of normal human gait using inertial unit (IMU) recordings in a walking test. METHODS: Gait analysis was conducted on 32 healthy participants (age range 19-29 years) at speeds of 2 km/h and 4 km/h using a treadmill. Dynamic data were obtained using a microcontroller (Arduino Nano 33 BLE Sense Rev2) with IMU sensors (BMI270). The collected data were processed and analyzed using a custom script (MATLAB 2022b), including the labeling of the four relevant gait phases and events (Stance, Toe-Off, Swing, and Heel Strike), computation of statistical features (64 features), and application of machine learning techniques for classification (8 classifiers). RESULTS: Spider plot analysis revealed significant differences in the four events created by the most relevant statistical features. Among the different classifiers tested, the Support Vector Machine (SVM) model using a Cubic kernel achieved an accuracy rate of 92.4% when differentiating between gait events using the computed statistical features. CONCLUSIONS: This study identifies the optimal features of acceleration and gyroscope data during normal gait. The findings suggest potential applications for injury prevention and performance optimization in individuals engaged in activities involving normal gait. The creation of spider plots is proposed to obtain a personalised fingerprint of each patient's gait fingerprint that could be used as a diagnostic tool. A deviation from a normal gait pattern can be used to identify human gait disorders. Moving forward, this information has potential for use in clinical applications in the diagnosis of gait-related disorders and developing novel orthoses and prosthetics to prevent falls and ankle sprains.

A Novel Device for Assessment and Treatment of Upper Cervical Spine: Test-Retest Reliability Study.

INTRODUCTION: Neck pain is one of the most frequent reasons for consultation in primary care. Clinicians evaluate different variables, including movement and cervical strength, to determine the prognosis of patients. Usually, the tools employed for this purpose are expensive and bulky, or more than one is needed. This study aims to describe a novel device designed to assess the cervical spine and describe its test-retest reliability. METHODS: The Spinetrack device was designed to measure the strength of deep cervical flexor muscles and the chin-in and chin-out movement of the upper cervical spine. A test-retest reliability study was developed. The flexion, extension and strength needed to move the Spinetrack device were registered. Two measurements were developed, with one week between each assessment. RESULTS: Twenty healthy subjects were evaluated. The strength of the deep cervical flexor muscles in the first measurement was 21.18 ± 3.15 Newtons, the displacement movement during chin-in movement was 12.79 mm ± 3.46 and the displacement during chin-out movement was 35.99 mm ± 4.44. The test-retest reliability of strength was ICC 0.97 (95% CI (0.91-0.99)). CONCLUSION: The Spinetrack device has shown excellent test-retest reliability values for the measurement of the strength of the cervical flexor muscles and for the chin-in and chin-out movements.

Parallel detection of chemical reactions in a microfluidic platform using hyperpolarized nuclear magnetic resonance.

The sensitivity of NMR may be enhanced by more than four orders of magnitude via dissolution dynamic nuclear polarization (dDNP), potentially allowing real-time, in situ analysis of chemical reactions. However, there has been no widespread use of the technique for this application and the major limitation has been the low experimental throughput caused by the time-consuming polarization build-up process at cryogenic temperatures and fast decay of the hyper-intense signal post dissolution. To overcome this limitation, we have developed a microfluidic device compatible with dDNP-MR spectroscopic imaging methods for detection of reactants and products in chemical reactions in which up to 8 reactions can be measured simultaneously using a single dDNP sample. Multiple MR spectroscopic data sets can be generated under the same exact conditions of hyperpolarized solute polarization, concentration, pH, and temperature. A proof-of-concept for the technology is demonstrated by identifying the reactants in the decarboxylation of pyruvate via hydrogen peroxide (e.g. 2-hydroperoxy-2-hydroxypropanoate, peroxymonocarbonate and CO2). dDNP-MR allows tracing of fast chemical reactions that would be barely detectable at thermal equilibrium by MR. We envisage that dDNP-MR spectroscopic imaging combined with microfluidics will provide a new high-throughput method for dDNP enhanced MR analysis of multiple components in chemical reactions and for non-destructive in situ metabolic analysis of hyperpolarized substrates in biological samples for laboratory and preclinical research.

Optical nanogap antennas as plasmonic biosensors for the detection of miRNA biomarkers.

Nanoplasmonic biosensors based on nanogap antenna structures usually demand complex and expensive fabrication processes in order to achieve a good performance and sensitive detection. We here report the fabrication of large-area nanoplasmonic sensor chips based on nanogap antennas by employing a customized, simple and low-cost colloidal lithography process. By precisely controlling the angle for tilted e-beam metal evaporation, an elliptical mask is produced, which defines the total length of the dipole antenna nanostructures while assuring that the plasmonic response is oriented in the same direction along the sensor chip. Large-area sensor chips of nanogap antennas formed by pairs of gold nanodisks separated by gaps with an average size of 11.6 ± 4.7 nm are obtained. The optical characterization of the nanogap antenna structures in an attenuated total reflection (ATR) configuration shows a bulk refractive index sensitivity of 422 nm per RIU, which is in agreement with FDTD numerical simulations. The biosensing potential of the cm2-sized nanostructured plasmonic sensor chips has been evaluated for the detection of miRNA-210, a relevant biomarker for lung cancer diagnosis, through a DNA/miRNA hybridization assay. A limit of detection (LOD) of 0.78 nM (5.1 ng mL-1) was achieved with no need of further amplification steps, demonstrating the high sensitivity of these plasmonic nanogap antennas for the direct and label-free detection of low molecular weight biomolecules such as miRNAs.

Label-Free Nanoplasmonic Biosensing of Cancer Biomarkers for Clinical Diagnosis.

Biosensing of cancer biomarkers enabling early diagnosis of cancer constitutes an essential tool for clinical intervention and application of novel therapies against cancer disease. Optical biosensor instruments as point-of-care (POC) devices and operating under label-free scheme have demonstrated to provide fast, simple, and high-sensitivity assays even at home care environment. Nanoplasmonic biosensors are thought to be a powerful tool for detection of complex analytes of relevant clinical applications. Using high-throughput fabrication techniques, large surface patterned with gold nanodisk structures is obtained showing surface sensitivities with limit of detection (LOD) in the order of picomolar concentration range. Here, we describe two major assay methodologies used for detection of lung and colorectal cancer, respectively. Particularly, we have selected a complementary hybridization DNA/RNA assay for the assessment of two miRNAs (miRNA-210 and miRNA-205) for detection of lung cancer. However, for colorectal cancer we present the detection of four tumor-associated antigen (TAA) biomarkers (MAPKAPK3, PIM-1, STK4, and GTF2B) as possible TAA targets for autoantibody production. Strategies for detecting these biomarkers in real samples such as serum are also presented, demonstrating the capabilities of these assays to be transferred to real clinical settings.

Nanoplasmonic biosensor device for the monitoring of acenocoumarol therapeutic drug in plasma.

Acenocoumarol (Sintrom®) is an oral anticoagulant prescribed for the treatment of a variety of thromboembolic disorders such as atrial fibrillation and thrombosis or embolism. It inhibits fibrin production preventing clot formation. Acenocoumarol has a narrow therapeutic range, and its effects depend on several factors, such as body weight, age, metabolism, diet, certain medical conditions or the intake of additional drugs, among others. A higher dose may result in the risk of bleeding, while if it is too low, the risk of blood clot can increase. Complementary tools that allow the therapeutic drug monitoring (TDM) of acenocoumarol plasmatic levels from the starting of the treatment would be of paramount importance to personalize the treatment. Point-of-care (POC) devices can offer an added value in facilitating on-site monitoring (i.e. hospitals, primary care doctor or even by the patient itself) and can aid in dosage management. With this aim, we have developed a compact and simple nanoplasmonic sensing device based on gold nanodisks for the rapid monitoring of acenocoumarol, using highly specific polyclonal antibodies produced against this drug. A specific and reproducible label free indirect competitive assay has been developed and the viability of performing the evaluation directly in plasma diluted 1:1 has been demonstrated. A limit of detection (LOD) of only 0.77 ±â€¯0.69 nM, an IC50 of 48.2 ±â€¯5.12 nM and a dynamic range between 3.38 ±â€¯1.33 nM and 1154 ±â€¯437 nM were achieved, which easily fit within the drug plasma levels of acenocoumarol, making this approach a highly attractive option for its decentralized monitoring in human plasma.

Highly sensitive SERS analysis of the cyclic Arg-Gly-Asp peptide ligands of cells using nanogap antennas.

The cyclic RGD (cRGD) peptide ligands of cells have become widely used for treating several cancers. We report a highly sensitive analysis of c(RGDfC) using surface enhanced Raman spectroscopy (SERS) using single dimer nanogap antennas in aqueous environment. Good agreement between characteristic peaks of the SERS and the Raman spectra of bulk c(RGDfC) with its peptide's constituents were observed. The exhibited blinking of the SERS spectra and synchronization of intensity fluctuations, suggest that the SERS spectra acquired from single dimer nanogap antennas was dominated by the spectrum of single to a few molecules. SERS spectra of c(RGDfC) could be used to detect at the nanoscale, the cells' transmembrane proteins binding to its ligand. SERS of cyclic RGD on nanogap antenna.

[Role of renal inflammation in the physiopathology of salt-sensitive hypertension]. / Papel de la inflamación renal en la fisiopatología de la hipertensión sensible a sal.

Salt-sensitive hypertension is produced by a decrease in salt renal excretion after a salt overload. Over the last few years, a new theory has been developed to explain this condition based on renal tissue inflammation. This process begins with free radicals production in renal tissue due to oxidative metabolism. Then they favor a renal inflammation mechanism with T-lymphocytes infiltration and other immune cells. Essentially, T-lymphocytes determine an increase in angiotensin ii production which raises sodium and water retention. Association among autoimmune diseases and hypertension may be explained, in part, by the relationship between salt-sensitive hypertension and renal inflammation. The use of antioxidant drugs and the development of new medicaments may be a choice for treating patients affected with this condition.

Papel de la inflamación renal en la fisiopatología de la hipertensión sensible a sal / Role of renal inflammation in the physiopathology of salt-sensitive hypertension

La hipertensión sensible a sal es el aumento de la presión arterial luego de una sobrecarga salina, como consecuencia esencialmente de una disminución en la excreción renal de sodio. En los últimos años, ha sido desarrollada una teoría para explicar su origen que tiene como base la inflamación del tejido renal. El proceso inicia con la producción en los riñones de radicales libres derivados del metabolismo oxidativo. Luego se desarrolla un mecanismo de inflamación del intersticio renal por infiltración de linfocitos T, y otras células inmunológicas. Fundamentalmente los linfocitos T incrementan la producción de angiotensina II que estimula la retención de sodio y agua a este nivel, favoreciendo el desarrollo de hipertensión sensible a sal. La relación entre infiltración renal por células del sistema inmune e hipertensión sensible a sal permite, en parte, explicar la asociación entre enfermedades autoinmunes y la hipertensión arterial. El uso de antioxidantes y el diseño de nuevos fármacos pueden ser una alternativa adicional al tratamiento de los pacientes afectados.

Salt-sensitive hypertension is produced by a decrease in salt renal excretion after a salt overload. Over the last few years, a new theory has been developed to explain this condition based on renal tissue inflammation. This process begins with free radicals production in renal tissue due to oxidative metabolism. Then they favor a renal inflammation mechanism with T-lymphocytes infiltration and other immune cells. Essentially, T-lymphocytes determine an increase in angiotensin II production which raises sodium and water retention. Association among autoimmune diseases and hypertension may be explained, in part, by the relationship between salt-sensitive hypertension and renal inflammation. The use of antioxidant drugs and the development of new medicaments may be a choice for treating patients affected with this condition.