Machine Learning Allows for Distinguishing Precancerous and Cancerous Human Epithelial Cervical Cells Using High-Resolution AFM Imaging of Adhesion Maps.

Previously, the analysis of atomic force microscopy (AFM) images allowed us to distinguish normal from cancerous/precancerous human epithelial cervical cells using only the fractal dimension parameter. High-resolution maps of adhesion between the AFM probe and the cell surface were used in that study. However, the separation of cancerous and precancerous cells was rather poor (the area under the curve (AUC) was only 0.79, whereas the accuracy, sensitivity, and specificity were 74%, 58%, and 84%, respectively). At the same time, the separation between premalignant and malignant cells is the most significant from a clinical point of view. Here, we show that the introduction of machine learning methods for the analysis of adhesion maps allows us to distinguish precancerous and cancerous cervical cells with rather good precision (AUC, accuracy, sensitivity, and specificity are 0.93, 83%, 92%, and 78%, respectively). Substantial improvement in sensitivity is significant because of the unmet need in clinical practice to improve the screening of cervical cancer (a relatively low specificity can be compensated by combining this approach with other currently existing screening methods). The random forest decision tree algorithm was utilized in this study. The analysis was carried out using the data of six precancerous primary cell lines and six cancerous primary cell lines, each derived from different humans. The robustness of the classification was verified using K-fold cross-validation (K = 500). The results are statistically significant at p < 0.0001. Statistical significance was determined using the random shuffle method as a control.

Identification of Geometrical Features of Cell Surface Responsible for Cancer Aggressiveness: Machine Learning Analysis of Atomic Force Microscopy Images of Human Colorectal Epithelial Cells.

It has been recently demonstrated that atomic force microscopy (AFM) allows for the rather precise identification of malignancy in bladder and cervical cells. Furthermore, an example of human colorectal epithelial cells imaged in AFM Ringing mode has demonstrated the ability to distinguish cells with varying cancer aggressiveness with the help of machine learning (ML). The previously used ML methods analyzed the entire cell image. The problem with such an approach is the lack of information about which features of the cell surface are associated with a high degree of aggressiveness of the cells. Here we suggest a machine-learning approach to overcome this problem. Our approach identifies specific geometrical regions on the cell surface that are critical for classifying cells as highly or lowly aggressive. Such localization gives a path to colocalize the newly identified features with possible clustering of specific molecules identified via standard bio-fluorescence imaging. The biological interpretation of the obtained information is discussed.

A Hydrogen-Bromate Flow Battery as a Rechargeable Chemical Power Source.

The hydrogen-bromate flow battery represents one of the promising variants for hybrid power sources. Its membrane-electrode assembly (MEA) combines a hydrogen gas diffusion anode and a porous flow-through cathode where bromate reduction takes place from its acidized aqueous solution: BrO3− + 6 H+ + 6 e− = Br− + 3 H2O (*). The process of electric current generation occurs on the basis of the overall reaction: 3 H2 + BrO3− = Br− + 3 H2O (**), which has been studied in previous publications. Until this work, it has been unknown whether this device is able to function as a rechargeable power source. This means that the bromide anion, Br−, should be electrooxidized into the bromate anion, BrO3−, in the course of the charging stage inside the same cell under strongly acidic conditions, while until now this process has only been carried out in neutral or alkaline solutions with specially designed anode materials. In this study, we have demonstrated that processes (*) and (**) can be performed in a cyclic manner, i.e., as a series of charge and discharge stages with the use of MEA: H2, Freidenberg H23C8 Pt-C/GP-IEM 103/Sigracet 39AA, HBr + H2SO4; square cross-section of 4 cm2 surface area, under an alternating galvanostatic mode at a current density of 75 mA/cm2. The coulombic, voltaic and energy efficiencies of the flow battery under a cyclic regime, as well as the absorption spectra of the catholyte, were measured during its operation. The total amount of Br-containing compounds penetrating through the membrane into the anode space was also determined.

Current Distribution in the Discharge Unit of a 10-Cell Vanadium Redox Flow Battery: Comparison of the Computational Model with Experiment.

Shunting currents are among the main problems of all-vanadium redox flow battery stacks since, in addition to capacity losses, they cause negative effects associated with the local destruction of electrodes and bipolar plates. The values of both the shunting currents and their destructive effects on materials can be reduced at the battery development stage by adjusting the resistance of the electrolyte supply channels. The solution to this problem can be found using a calculation model for current distribution based on the current balance in the nodes as well as voltage drops and electromotive force in internal circuits according to Kirchhoff's laws. This paper presents the verification of the model of current distribution in an all-vanadium redox flow battery stack of an original design that allows for the determination of membrane-electrode assembly resistances and electrolyte supply channels via direct measurements. Based on a comparison of the calculated and experimental values of the coulombic efficiency of charge-discharge cycles, the capacity fade associated with the crossover of vanadium compounds through the membrane has been determined.

Mixture of Anthraquinone Sulfo-Derivatives as an Inexpensive Organic Flow Battery Negolyte: Optimization of Battery Cell.

Anthraquinone-2,7-disulfonic acid (2,7-AQDS) is a promising organic compound, which is considered as a negolyte for redox flow batteries as well as for other applications. In this work we carried out a well-known reaction of anthraquinone sulfonation to synthesize 2,7-AQDS in mixture with other sulfo-derivatives, namely 2,6-AQDS and 2-AQS. Redox behavior of this mixture was evaluated with cyclic voltammetry and was almost identical to 2,7-AQDS. Mixture was then assessed as a potential negolyte of anthraquinone-bromine redox flow battery. After adjusting membrane-electrode assembly composition (membrane material and flow field)), the cell demonstrated peak power density of 335 mW cm-2 (at SOC 90%) and capacity utilization, capacity retention and energy efficiency of 87.9, 99.6 and 64.2%, respectively. These values are almost identical or even higher than similar values for flow battery with 2,7-AQDS as a negolyte, while the price of mixture is significantly lower. Therefore, this work unveils the promising possibility of using a mixture of crude sulfonated anthraquinone derivatives mixture as an inexpensive negolyte of RFB.

Analysis of the Composition of Bromide Anion Oxidation Products in Aqueous Solutions with Different pH via Rotating Ring-Disk Electrode Method.

We measured the ring collection coefficient of bromide anion oxidation products in a neutral and slightly alkaline medium on a rotating ring-disk electrode (glassy carbon disk, platinum ring) varying the following parameters: disk electrode rotation velocity, sodium bromide concentration, pH of the medium (in the range of 6−12), anode current on the disk, and the electroreduction potential of the bromide anion oxidation products on the ring. The data obtained are presented via dependences of the cathode ring current on the disk current ratio vs. the ring electrode potential. The analysis of the results was carried out by comparing the experimental polarization curves of the ring electrode with the data of cyclic voltammetry in model solutions to determine the electrical activities of various bromine compounds in positive oxidation states. We claim that the RRDE method could be used to obtain quantitative and qualitative data on the electrooxidation of bromide ions in neutral and alkaline solutions. For the most effective regeneration of the spent oxidizer, the values of pH > 10 and moderate concentrations of NaBr should be used.

Bromine Crossover in Operando Analysis of Proton Exchange Membranes in Hydrogen-Bromate Flow Batteries.

The manuscript deals with the fundamental problem of platinum hydrogen oxidation catalyst poisoning of the hybrid chemical power source based on bromate electroreduction and hydrogen electro-oxidation reactions. The poisoning is caused by the crossover of bromine-containing species through the proton exchange membrane separating compartments of the flow cell. Poisoning results in a drastic decrease in the flow cell performance. This paper describes the results of the direct measurement of bromine-containing species' crossover through perfluorosulfonic acid membranes of popular vendors in a hydrogen-bromate flow cell and proposes corresponding scenarios for the flow battery charge-discharge operation based on the electrolyte's control of the pH value. The rate of the crossover of the bromine-containing species through the membrane is found to be inversely proportional to the membrane thickness.

Two-Membrane Acid-Base Flow Battery with Hydrogen Electrodes for Neutralization-to-Electrical Energy Conversion.

Acid-base flow batteries (ABFB) are a promising and environmentally benign class of flow batteries that utilize neutralization energy. Among the other flow batteries, ABFBs stand out with low cost and high solubility of the electrolytes and the possibility to harvest neutralization energy of acidic and alkaline wastewaters. However, the main ABFB issues, such as low power caused by discharge current limitation and low energy density, are limiting the possibility of their implementation. In this work, a novel two-membrane ABFB with two hydrogen electrodes was developed to overcome main ABFB issues. The proposed concept demonstrated high power density up to 6.1 mW cm-2 at 13 mA cm-2 . It was shown that battery performance was greatly limited by negative electrode overvoltage. Analysis of the voltage losses allowed to estimate main power losses and highlight the possible ways to its minimization.

Electrolyte Flow Field Variation: A Cell for Testing and Optimization of Membrane Electrode Assembly for Vanadium Redox Flow Batteries.

A great deal of research has been dedicated to improving the performance of vanadium redox flow battery (VRFB). In this work, we propose the design of a cell for testing membrane electrode assembly of VRFB, which enables the optimization of the flow field, conditions of charge-discharge tests, and the nature of components (electrodes, membrane) with minimal time and material expenses. The essence of the proposed cell is that the system of channels distributing the electrolyte is made by cutting shaped holes in the sheets of graphite foil (GF). This manner allows easy modification of the flow field configurations. Polarization curves for serpentine, interdigitated, and flow-through systems were measured according to procedures used in such studies. Cell with GF plates being tested with vanadium-sulfuric acid electrolyte, outperforms the cell with conventional graphite plates with the same parameters of the flow field. It demonstrates 734 mW cm-2 of peak power density at SOC 50 and 84.3 % of energy efficiency at 84.5 % of electrolyte utilization under galvanostatic charge/discharge cycling with 75 mA cm-2 .

Manipulation Technique for Precise Transfer of Single Perovskite Nanoparticles.

In this article, we present the pick-and-place technique for the manipulation of single nanoparticles on non-conductive substrates using a tungsten tip irradiated by a focused electron beam from a scanning electron microscope. The developed technique allowed us to perform the precise transfer of single BaTiO3 nanoparticles from one substrate to another in order to carry out measurements of elastic light scattering as well as second harmonic generation. Also, we demonstrate a fabricated structure made by finely tuning the position of a BaTiO3 nanoparticle on top of a dielectric nanowaveguide deposited on a glass substrate. The presented technique is based on the electrostatic interaction between the sharp tungsten tip charged by the electron beam and the nanoscale object. A mechanism for nanoparticle transfer to a non-conductive substrate is proposed and the forces involved in the manipulation process are evaluated. The presented technique can be widely utilized for the fabrication of nanoscale structures on optically transparent non-conductive substrates, which presents a wide range of applications for nanophotonics.

Dataset of a vanadium redox flow battery 10 membrane-electrode assembly stack.

This paper contains a vanadium redox flow battery stack with an electrode surface area 40 cm2 test data. The aim of the study was to characterize the performance of the stack of the original design. The dataset include three series of galvanostatic charge-discharge cycling in the potential region 8-16 V with current densities 75, 150 and 200 mA/cm2 for 100 cycles. Coulomb, voltaic, energy efficiencies and capacity utilization coefficient are also provided for all three series.

Updates on the Role of Imaging in Cardiac Sarcoidosis.

PURPOSE OF REVIEW: The non-specific symptom profile and subclinical nature of disease along with variable region of cardiac involvement in systemic sarcoidosis make the diagnosis particularly challenging. The yield of endomyocardial biopsy, a gold standard for diagnosis, is not high unless coupled with additional imaging modalities to detect regional involvement. This review is focused on highlighting the major recent advances in imaging modalities and diagnosis of cardiac sarcoidosis. RECENT FINDINGS: There has been much interest and increasing research focused on developing newer and improved imaging modalities to establish diagnosis. CMR and 18F- FDG-PET are now considered imaging modalities of choice in most centers worldwide, but the data comparing both methodologies head-to-head is limited. Nevertheless, novel radiotracers (i.e. 68Ga-DOTANOC, 18F-Flurpiridaz, 13N-Ammonia) and hybrid combination PET/CMR imaging are coming to spotlight with improved sensitivity and specificity for earlier detection of myocardial sarcoid. As CMR and PET are showing increased utilization in cardiac sarcoidosis, 201Th-SPECT, 99mTc MDP SPECT, 67Ga Scintigraphy, and 82Rb PET are falling out of favor. Newer imaging modalities, radionuclide tracers, and hybrid PET/CMR combinations have been promising in better detecting cardiac sarcoidosis and are currently being evaluated in larger trials.

Peripheral Arterial Disease in Women: an Overview of Risk Factor Profile, Clinical Features, and Outcomes.

PURPOSE OF REVIEW: Peripheral arterial disease (PAD) is the third most common manifestation of cardiovascular disease (CVD), following coronary artery disease (CAD) and stroke. PAD remains underdiagnosed and under-treated in women. RECENT FINDINGS: Women with PAD experience more atypical symptoms and poorer overall health status. The prevalence of PAD in women increases with age, such that more women than men have PAD after the age of 40 years. There is under-representation of PAD patients in clinical trials in general and women in particular. In this article, we address the lack of women participants in PAD trials. We then present a comprehensive overview of the epidemiology/risk factor profile, clinical features, treatment, and outcomes. PAD is prevalent in women and its global burden is on the rise despite a decline in global age-standardized death rate from CVD. The importance of this issue has been underlined by the American Heart Association's (AHA) "Call to Action" scientific statement on PAD in women. Large-scale campaigns are needed to increase awareness among physicians and the general public. Furthermore, effective treatment strategies must be implemented.

Cardiac Sarcoidosis: A Review of Contemporary Challenges in Diagnosis and Treatment.

Sarcoidosis is a systemic disease characterized by noncaseating granulomas and is often a diagnosis of exclusion. The actual prevalence of cardiac sarcoidosis (CS) is unknown, as studies have demonstrated mixed data. CS may be asymptomatic and is likely more frequently encountered than previously thought. Sudden death may often be the presenting feature of CS. Most deaths attributed to CS are caused by arrhythmias or conduction system disease, and congestive heart failure may occur. Current expert consensus on diagnosis of CS continues to rely on endomyocardial biopsy, in the absence of which, histologic proof of extracardiac sarcoid involvement is necessitated. Emergence of newer noninvasive imaging modalities such as cardiac magnetic resonance imaging and positron emission tomography, have become increasingly popular tools utilized in patients with both clinical and asymptomatic CS, and have demonstrated good diagnostic capability. The main therapeutic approaches in patients with CS can be broadly divided into the following 2 categories: pharmacological management and invasive or device oriented. However, much remains unknown about the optimal screening protocols of asymptomatic patients with extracardiac sarcoidosis and treatment of biopsy-proven CS. Our knowledge about CS has amplified significantly over the last 30 years and the growing realization that this process is often asymptomatic is paving the way for better screening protocols and earlier detection of this serious condition.

An unusual cause of rhabdomyolysis in emergency setting: challenges of diagnosis.

Rhabdomyolysis is a rare phenomenon that may be challenging to recognize in an emergency setting. Drugs are one of the common causes. Trimethoprim-sulfamethoxazole is a commonly used antibiotic effective in the treatment of upper and lower respiratory tract infections as well as renal, urinary, and gastrointestinal tract infections. It has variable side effects, ranging from mild symptoms of fatigue and insomnia to a potentially life-threatening Steven-Johnson syndrome and renal failure. Rhabdomyolysis is a rare complication of therapy with this drug and is commonly seen in immunocompromised patients or those with an allogenic stem cell transplant. In this article, we report a case of rhabdomyolysis in an immunocompetent patient who has undergone treatment with trimethoprim-sulfamethoxazole and a possible drug interaction with nonsteroidal anti-inflammatory drugs, with the latter acting as an aggravating factor of this complication.

A new synthesis of benzo[b]thiophene-2-thiolates and their derivatives via base-promoted transformation of 4-(2-mercaptophenyl)-1,2,3-thiadiazoles.

A reaction of 4-(2-mercaptophenyl)-1,2,3-thiadiazoles with an oxidant in the presence of 1.1 equiv of base afforded good yields of benzo[4,5]thieno[3,2-d][1,2,3]thiadiazoles via the intramolecular oxidative nucleophilic substitution of a hydrogen (ONHS) pathway. The reaction of 4-(2-mercaptophenyl)-1,2,3-thiadiazoles in the presence of ≥2 equiv of base gave 2-mercaptobenzo[b]thiophenes via an anionic ring-opening/ring-closure pathway.

A novel synthesis of benzo[b]selenophenes via regioselective intramolecular transformation of 4-(3-nitroaryl)-1,2,3-selenadiazoles.

Base-promoted transformation of 4-(3-nitroaryl)-1,2,3-selenadiazoles via intermediate formation of eneselenolates followed by 5-exo-trig cyclization is reported. The regiochemistry of the intramolecular cyclization is condition-dependent. In the presence of an oxidant, the oxidative nucleophilic substitution of the hydrogen (ONSH, S(N)Ar(H)) pathway, by oxidative aromatization of the rapidly formed σ(H)-adduct, takes place. In the absence of oxidant, the reaction proceeds via intermediate formation of the σ(Cl)-adduct, following nucleophilic aromatic substitution of the halogen (S(N)Ar(Cl)) pathway.

Tunable optical antennas based on metallic nanoshells with nanoknobs.

We investigate optical properties of a new complex plasmonic nanostructure, which consists of a spherical metallic nanoshell and a small metallic nanoparticle ("nanoknob") situated on its surface. The plasmon resonance wavelength of the entire structure is guided by the geometrical and material properties of the nanoshell whereas the electromagnetic field of the incident light is localized and enhanced near the "nanoknob". The idea is supported with electromagnetic modeling and near-field optical microscopy imaging. In addition, we proposed and demonstrated a new method of nanoparticle precise manipulation under electron beam, which could be used in fabrication of such plasmonic structures and other nanosized elements.

Optical detection of the Casimir force between macroscopic objects.

We report the optical detection of mechanical deformation of a macroscopic object induced by the Casimir force. An adaptive holographic interferometer based on a photorefractive BaTiO3:Co crystal was used to measure periodical nonlinear deformations of a thin pellicle caused by an oscillating Casimir force. A reasonable agreement between the experimental and calculated values of the first and second harmonics of the Casimir force oscillations has been obtained.

Precise subnanometer control of the position of a macro object by light pressure.

For the first time to the authors' knowledge, efficient control of the position of a macro object by coherent light was demonstrated. The minimal controllable mechanical displacement induced by the light pressure was 9 pm. No dependence of light pressure on wavelength in a broad wavelength range (405-1560 nm) was observed, as predicted by Maxwell's theory.