Bidimensional ensemble entropy: Concepts and application to emphysema lung computerized tomography scans.

BACKGROUND AND OBJECTIVE: Bidimensional entropy algorithms provide meaningful quantitative information on image textures. These algorithms have the advantage of relying on well-known one-dimensional entropy measures dedicated to the analysis of time series. However, uni- and bidimensional algorithms require the adjustment of some parameters that influence the obtained results or even findings. To address this, ensemble entropy techniques have recently emerged as a solution for signal analysis, offering greater stability and reduced bias in data patterns during entropy estimation. However, such algorithms have not yet been extended to their two-dimensional forms. METHODS: We therefore propose six bidimensional algorithms, namely ensemble sample entropy, ensemble permutation entropy, ensemble dispersion entropy, ensemble distribution entropy, and two versions of ensemble fuzzy entropy based on different models or parameters initialization of an entropy algorithm. These new measures are first tested on synthetic images and further applied to a biomedical dataset. RESULTS: The results suggest that ensemble techniques are able to detect different levels of image dynamics and their degrees of randomness. These methods lead to more stable entropy values (lower coefficients of variations) for the synthetic data. The results also show that these new measures can obtain up to 92.7% accuracy and 88.4% sensitivity when classifying patients with pulmonary emphysema through a k-nearest neighbors algorithm. CONCLUSIONS: This is a further step towards the potential clinical deployment of bidimensional ensemble approaches to detect different levels of image dynamics and their successful performance on emphysema lung computerized tomography scans. These bidimensional ensemble entropy algorithms have potential to be used in various imaging applications thanks to their ability to distinguish more stable and less biased image patterns compared to their original counterparts.

Evaluation of COVID-19 chest computed tomography: A texture analysis based on three-dimensional entropy.

Radiologists, and doctors in general, need relevant information for the quantification and characterization of pulmonary structures damaged by severe diseases, such as the Coronavirus disease 2019 (COVID-19). Texture-based analysis in scope of other pulmonary diseases has been used to screen, monitor, and provide valuable information for several kinds of diagnoses. To differentiate COVID-19 patients from healthy subjects and patients with other pulmonary diseases is crucial. Our goal is to quantify lung modifications in two pulmonary pathologies: COVID-19 and idiopathic pulmonary fibrosis (IPF). For this purpose, we propose the use of a three-dimensional multiscale fuzzy entropy (MFE3D) algorithm. The three groups tested (COVID-19 patients, IPF, and healthy subjects) were found to be statistically different for 9 scale factors ( p < 0.01 ). A complexity index (CI) based on the sum of entropy values is used to classify healthy subjects and COVID-19 patients showing an accuracy of 89.6 % , a sensitivity of 96.1 % , and a specificity of 76.9 % . Moreover, 4 different machine-learning models were also used to classify the same COVID-19 dataset for comparison purposes.

Formal verification of Matrix based MATLAB models using interactive theorem proving.

MATLAB is a software based analysis environment that supports a high-level programing language and is widely used to model and analyze systems in various domains of engineering and sciences. Traditionally, the analysis of MATLAB models is done using simulation and debugging/testing frameworks. These methods provide limited coverage due to their inherent incompleteness. Formal verification can overcome these limitations, but developing the formal models of the underlying MATLAB models is a very challenging and time-consuming task, especially in the case of higher-order-logic models. To facilitate this process, we present a library of higher-order-logic functions corresponding to the commonly used matrix functions of MATLAB as well as a translator that allows automatic conversion of MATLAB models to higher-order logic. The formal models can then be formally verified in an interactive theorem prover. For illustrating the usefulness of the proposed library and approach, we present the formal analysis of a Finite Impulse Response (FIR) filter, which is quite commonly used in digital signal processing applications, within the sound core of the HOL Light theorem prover.

Three-Dimensional Multiscale Fuzzy Entropy: Validation and Application to Idiopathic Pulmonary Fibrosis.

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, severe, and progressive lung disease with short life expectancy. Based on information theory and entropy measurement, a three-dimensional multiscale fuzzy entropy (MFE 3D) algorithm is proposed to identify IPF patients from their computed tomography (CT) volumetric data. First, the validation of the algorithm was performed by analyzing several volumetric synthetic noises (white, blue, brown, and pink), MIX(p) processes-based volumes, and texture-based volumes. The entropy values obtained by MFE 3D were consistent with the values obtained using the one, and two-dimensional versions, validating its use in biomedical data. Hence, MFE 3D was applied to CT scans to identify the existence of IPF within two different groups, one of healthy subjects (26) and another of IPF patients (26). Statistical differences were found (p < 0.05) between the entropy values of each group in 5 scale factors out of 10. These results demonstrate that MFE 3D could be an interesting metric to identify IPF in CT scans.

Impact on sexual function of surgical treatment in rectal cancer

ABSTRACT Introduction The development of new surgical techniques and medical devices, like therapeutical multimodal approaches has allowed for better outcomes on patients with rectal cancer (RCa). Owing to that, an increased awareness and investment towards better outcomes regarding patients' sexual and urinary function has been recently observed. Aim Evaluate and characterize the sexual dysfunction of patients submitted to surgical treatment for RCa. Materials and Methods An observational retrospective study including all male patients who underwent a surgical treatment for RCa between January 2011 December 2014 (n=43) was performed, complemented with an inquiry questionnaire to every patient about its sexual habits and level of function before and after surgery. Discussion All patients were male, with an average of 64yo. (range 42-83yo.). The surgical procedure was a rectum anterior resection (RAR) in 22 patients (56%) and an abdominoperineal resection (APR) in 19(44%). Sixty three percent described their sexual life as important/very important. Sexual function worsening was observed in 76% (65% with complains on erectile function, and 27% on ejaculation). Fourteen patients (38%) didn't resume sexual activity after surgery. Increased age (p=0.007), surgery performed (APR) (p=0.03) and the presence of a stoma (p=0.03) were predictors of ED after surgery. A secondary analysis found that the type of surgery (APR) (p=0.04), lower third tumor's location (p=0.03) and presence of comorbidities (p=0.013) (namely, smokers and diabetic patients) were predictors of de novo ED after surgery. Conclusions This study demonstrated the clear negative impact in sexual function of patients submitted to a surgical treatment for RCa. Since it is a valued feature for patients, it becomes essential to correctly evaluate/identify these cases in order to offer an adequate therapeutical option.

Impact on sexual function of surgical treatment in rectal cancer.

INTRODUCTION: The development of new surgical techniques and medical devices, like therapeutical multimodal approaches has allowed for better outcomes on patients with rectal cancer (RCa). Owing to that, an increased awareness and investment towards better outcomes regarding patients' sexual and urinary function has been recently observed. AIM: Evaluate and characterize the sexual dysfunction of patients submitted to surgical treatment for RCa. MATERIALS AND METHODS: An observational retrospective study including all male patients who underwent a surgical treatment for RCa between January 2011 December 2014 (n=43) was performed, complemented with an inquiry questionnaire to every patient about its sexual habits and level of function before and after surgery. DISCUSSION: All patients were male, with an average of 64yo. (range 42-83yo.). The surgical procedure was a rectum anterior resection (RAR) in 22 patients (56%) and an abdominoperineal resection (APR) in 19(44%). Sixty three percent described their sexual life as important/very important. Sexual function worsening was observed in 76% (65% with complains on erectile function, and 27% on ejaculation). Fourteen patients (38%) didn't resume sexual activity after surgery. Increased age (p=0.007), surgery performed (APR) (p=0.03) and the presence of a stoma (p=0.03) were predictors of ED after surgery. A secondary analysis found that the type of surgery (APR) (p=0.04), lower third tumor's location (p=0.03) and presence of comorbidities (p=0.013) (namely, smokers and diabetic patients) were predictors of de novo ED after surgery. CONCLUSIONS: This study demonstrated the clear negative impact in sexual function of patients submitted to a surgical treatment for RCa. Since it is a valued feature for patients, it becomes essential to correctly evaluate/identify these cases in order to offer an adequate therapeutical option.

Ag(I) camphorimine complexes with antimicrobial activity towards clinically important bacteria and species of the Candida genus.

The present work follows a previous report describing the antibacterial activity of silver camphorimine complexes of general formula [Ag(NO3)L]. The synthesis and demonstration of the antifungal and antibacterial activity of three novel [Ag(NO3)L] complexes (named 1, 2 and 3) is herein demonstrated. This work also shows for the first time that the previously studied complexes (named 4 to 8) also exert antifungal activity. The antibacterial activity of complexes was evaluated against Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia contaminans and Escherichia coli strains, while antifungal activity was tested against the Candida species C. albicans, C. glabrata, C. parapsilosis and C. tropicalis. The antimicrobial activity of the complexes ranged from very high (complex 4) to moderate (complex 6) or low (complex 8), depending on the structural and electronic characteristics of the camphorimine ligands. Notably, the highest antibacterial and anti-Candida activities do not coincide in the same complex and in some cases they were even opposite, as is the case of complex 4 which exhibits a high anti-bacterial and low antifungal activity. These distinct results suggest that the complexes may have different mechanisms against prokaryotic and eukaryotic cells. The antifungal activity of the Ag(I) camphorimine complexes (in particular of complex 1) was found to be very high (MIC = 2 µg/mL) against C. parapsilosis, being also registered a prominent activity against C. tropicalis and C. glabrata. None of the tested compounds inhibited C. albicans growth, being this attributed to the ability of these yeast cells to mediate the formation of less toxic Ag nanoparticles, as confirmed by Scanning Electron Microscopy images. The high antibacterial and anti-Candida activities of the here studied camphorimine complexes, especially of complexes 1 and 7, suggests a potential therapeutic application for these compounds.

Synthesis of Ag(I) camphor sulphonylimine complexes and assessment of their cytotoxic properties against cisplatin-resistant A2780cisR and A2780 cell lines.

Camphorsulphonylimine complexes [Ag(NO3)(IL)2] (IL=C12H19N3SO2, 1) and [(AgNO3)2(IIL)] (IIL=C22H23N3SO2, 2) were synthesized and characterized by elemental analysis, spectroscopy (IR, NMR) and cyclic voltammetry. [Ag(NO3)(IL)2] crystalizes in the monoclinic C2 space group with a triangular geometry assuming a chalice-type shape. The anti-proliferative properties of the new complexes 1 and 2 and those of the previously reported [Ag(NO3)(IIIL)] (IIIL=C16H18N3SO2, 3) were assessed against the human ovarian cancer cells (cisplatin-sensitive A2780, cisplatin-resistant A2780cisR) and the non-tumoral human HEK 293 cell line, using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The NR (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) assay was alternatively used to assess the cytotoxicity on the A2780 cells. Results from the MTT assay (48h exposure) show that the complexes display IC50 values lower (by at least one order of magnitude) than cisplatin, while the cytotoxicity of AgNO3 is of the same order of cisplatin. The camphorsulphonylimine ligands display irrelevant (IL, IIIL) or no cytotoxicity (IIL). The highest cytotoxicity (lower IC50) was found for [(AgNO3)2(IIL)]. The binding ability of the complexes to calf thymus-deoxyribonucleic acid (CT-DNA) was studied by fluorescence. Constants (Ksv, Ka) and the number (n) of binding centres to DNA were calculated showing that DNA intercalation possibly occurs in the cases of complexes 2 and 3, while a more complicated process operates for 1. As expected from the cytotoxicity, [(AgNO3)2(IIL)] displays the highest binding affinity (Ka=1.61×105 M-1). No binding to DNA was detected for AgNO3 or IIL under the experimental conditions used. The binding trend to CT-DNA found by fluorescence was corroborated by cyclic voltammetry.

Laser spectroscopy of muonic deuterium.

The deuteron is the simplest compound nucleus, composed of one proton and one neutron. Deuteron properties such as the root-mean-square charge radius rd and the polarizability serve as important benchmarks for understanding the nuclear forces and structure. Muonic deuterium µd is the exotic atom formed by a deuteron and a negative muon µ(-). We measured three 2S-2P transitions in µd and obtain r(d) = 2.12562(78) fm, which is 2.7 times more accurate but 7.5σ smaller than the CODATA-2010 value r(d) = 2.1424(21) fm. The µd value is also 3.5σ smaller than the r(d) value from electronic deuterium spectroscopy. The smaller r(d), when combined with the electronic isotope shift, yields a "small" proton radius r(p), similar to the one from muonic hydrogen, amplifying the proton radius puzzle.

Antibacterial activity of silver camphorimine coordination polymers.

Five new silver camphorimine complexes of general formula [Ag(NO3)(Y)L] were synthesized and fully characterized using spectroscopic and analytical techniques. The structure of [Ag(NO3)(OC10H14NC6H4NC10H14O)] () was analyzed using single crystal X-ray diffraction, showing that it arranges as a coordination polymer formed by sequential Ag(NO3) units bridged by the bi-camphor ligand (). The antimicrobial properties of the new complexes were screened using the disk diffusion method and their Minimal Inhibitory Concentrations (MIC) were assessed against selected bacterial strains of the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli, Pseudomonas aeruginosa, and Burkholderia contaminans. The lowest MICs were observed for , with estimated values of 72, 20, 32 and 19 µg mL(-1) for S. aureus, E. coli, B. contaminans, and P. aeruginosa, respectively. In the case of S. aureus, similar MIC values were obtained for silver nitrate and compound . All five compounds were bactericidal when used in concentrations equal or above the MIC value, as found by enumerating the total colony forming units (CFUs) after incubation in their presence.

Aß and NMDAR activation cause mitochondrial dysfunction involving ER calcium release.

Early cognitive deficits in Alzheimer's disease (AD) seem to be correlated to dysregulation of glutamate receptors evoked by amyloid-beta (Aß) peptide. Aß interference with the activity of N-methyl-d-aspartate receptors (NMDARs) may be a relevant factor for Aß-induced mitochondrial toxicity and neuronal dysfunction. To evaluate the role of mitochondria in NMDARs activation mediated by Aß, we followed in situ single-cell simultaneous measurement of cytosolic free Ca(2+)(Cai(2+)) and mitochondrial membrane potential in primary cortical neurons. Our results show that direct exposure to Aß + NMDA largely increased Cai(2+) and induced immediate mitochondrial depolarization, compared with Aß or NMDA alone. Mitochondrial depolarization induced by rotenone strongly inhibited the rise in Cai(2+) evoked by Aß or NMDA, suggesting that mitochondria control Ca(2+) entry through NMDARs. However, incubation with rotenone did not preclude mitochondrial Ca(2+) (mitCa(2+)) retention in cells treated with Aß. Aß-induced Cai(2+) and mitCa(2+) rise were inhibited by ifenprodil, an antagonist of GluN2B-containing NMDARs. Exposure to Aß + NMDA further evoked a higher mitCa(2+) retention, which was ameliorated in GluN2B(-/-) cortical neurons, largely implicating the involvement of this NMDAR subunit. Moreover, pharmacologic inhibition of endoplasmic reticulum (ER) inositol-1,4,5-triphosphate receptor (IP3R) and mitCa(2+) uniporter (MCU) evidenced that Aß + NMDA-induced mitCa(2+) rise involves ER Ca(2+) release through IP3R and mitochondrial entry by the MCU. Altogether, data highlight mitCa(2+) dyshomeostasis and subsequent dysfunction as mechanisms relevant for early neuronal dysfunction in AD linked to Aß-mediated GluN2B-composed NMDARs activation.

Highly effective water oxidation catalysis with iridium complexes through the use of NaIO4.

Exceptional water oxidation (WO) turnover frequencies (TOF=17,000 h(-1)), and turnover numbers (TONs) close to 400,000, the largest ever reported for a metal-catalyzed WO reaction, have been found by using [Cp*Ir(III)(NHC)Cl2] (in which NHC=3-methyl-1-(1-phenylethyl)-imidazoline-2-ylidene) as the pre-catalyst and NaIO4 as oxidant in water at 40 °C. The apparent TOF for [Cp*Ir(III)(NHC)X2] (1X, in which X stands for I (1I), Cl (1Cl), or triflate anion (1OTf)) and [(Cp*-NHCMe)Ir(III)I2] (2) complexes, is kept constant during almost all of the O2 evolution reaction when using NaIO4 as oxidant. The TOF was found to be dependent on the ligand and on the anion (TOF ranging from ≈600 to ≈1100 h(-1) at 25 °C). Degradation of the complexes by oxidation of the organic ligands upon reaction with NaIO4 has been investigated. (1)H NMR, ESI-MS, and dynamic light-scattering measurements (DLS) of the reaction medium indicated that the complex undergoes rapid degradation, even at low equivalents of oxidant, but this process takes place without formation of nanoparticles. Remarkably, three-month-old solution samples of oxidized pre-catalysts remain equally as active as freshly prepared solutions. A UV/Vis feature band at λmax =405 nm is observed in catalytic reaction solutions only when O2 evolves, which may be attributed to a resting state iridium speciation, most probably Ir-oxo species with an oxidation state higher than IV.

Proton structure from the measurement of 2S-2P transition frequencies of muonic hydrogen.

Accurate knowledge of the charge and Zemach radii of the proton is essential, not only for understanding its structure but also as input for tests of bound-state quantum electrodynamics and its predictions for the energy levels of hydrogen. These radii may be extracted from the laser spectroscopy of muonic hydrogen (µp, that is, a proton orbited by a muon). We measured the 2S(1/2)(F=0)-2P(3/2)(F=1) transition frequency in µp to be 54611.16(1.05) gigahertz (numbers in parentheses indicate one standard deviation of uncertainty) and reevaluated the 2S(1/2)(F=1)-2P(3/2)(F=2) transition frequency, yielding 49881.35(65) gigahertz. From the measurements, we determined the Zemach radius, r(Z) = 1.082(37) femtometers, and the magnetic radius, r(M) = 0.87(6) femtometer, of the proton. We also extracted the charge radius, r(E) = 0.84087(39) femtometer, with an order of magnitude more precision than the 2010-CODATA value and at 7σ variance with respect to it, thus reinforcing the proton radius puzzle.

Unprecedented synthesis of iron-NHC complexes by C-H activation of imidazolium salts. Mild catalysts for reduction of sulfoxides.

A direct synthesis of bidentate cyclopentadienyl-functionalised NHC-iron(II) complexes by using imidazolium salts and commercially available Fe(3)(CO)(12) is developed. These well-defined iron-NHC complexes efficiently catalyse the reduction of sulfoxides under mild conditions. Radical scavenging experiments indicate the presence of free radicals in the catalytic reaction.

Characterization of a double probe for local pulse wave velocity assessment.

Local pulse-wave velocity (PWV) is an accurate indicator of the degree of arteriosclerosis (stiffness) in an artery, providing a direct characterization of the properties of its wall. Devices currently available for local PWV measurement are mainly based on ultrasound systems and have not yet been generalized to clinical practice since they require high technical expertise and most of them are limited in precision, due to the lack of reliable signal processing methods. The present work describes a new type of probe, based on a double-headed piezoelectric (PZ) sensor. The principle of PWV measurement involves determination of the pulse transit time between the signals acquired simultaneously by both PZs, placed 23 mm apart. The double probe (DP) characterization is accomplished in three main studies, carried out in a dedicated test bench system, capable of reproducing a range of clinically relevant properties of the cardiovascular system. The first study refers to determination of the impulse response (IR) for each PZ sensor, whereas the second one explores the existence of crosstalk between both transducers. In the last one, DP time resolution is inferred from a set of three different algorithms based on (a) the maximum of cross-correlation function, (b) the maximum amplitude detection and (c) the zero-crossing point identification. These values were compared with those obtained by the reference method, which consists of the simultaneous acquisition of pressure waves by means of two pressure sensors. The new probe demonstrates good performance on the test bench system and results show that the signals do not exhibit crosstalk. A good agreement was also verified between the PWV obtained from the DP signals (19.55 ± 2.02 ms(-1)) and the PWV determined using the reference method (19.26 ± 0.04 ms(-1)). Although additional studies are still required, this probe seems to be a valid alternative to local PWV stand-alone devices.

The size of the proton.

The proton is the primary building block of the visible Universe, but many of its properties-such as its charge radius and its anomalous magnetic moment-are not well understood. The root-mean-square charge radius, r(p), has been determined with an accuracy of 2 per cent (at best) by electron-proton scattering experiments. The present most accurate value of r(p) (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants. This value is based mainly on precision spectroscopy of atomic hydrogen and calculations of bound-state quantum electrodynamics (QED; refs 8, 9). The accuracy of r(p) as deduced from electron-proton scattering limits the testing of bound-state QED in atomic hydrogen as well as the determination of the Rydberg constant (currently the most accurately measured fundamental physical constant). An attractive means to improve the accuracy in the measurement of r(p) is provided by muonic hydrogen (a proton orbited by a negative muon); its much smaller Bohr radius compared to ordinary atomic hydrogen causes enhancement of effects related to the finite size of the proton. In particular, the Lamb shift (the energy difference between the 2S(1/2) and 2P(1/2) states) is affected by as much as 2 per cent. Here we use pulsed laser spectroscopy to measure a muonic Lamb shift of 49,881.88(76) GHz. On the basis of present calculations of fine and hyperfine splittings and QED terms, we find r(p) = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value of 0.8768(69) fm. Our result implies that either the Rydberg constant has to be shifted by -110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient.

Simultaneous gastric and colic laparoscopic adjustable gastric band migration. Complication of bariatric surgery.

Laparoscopic adjustable gastric banding (LAGB) is a minimally invasive treatment for morbid obesity, which has proved its safety, efficiency, and reversibility. Postoperative complications are rare and might be related with the reservoir, connecting tube, or with the band itself. The lack or unspecificity of clinical signs and symptoms makes the diagnosis of gastric band erosion difficult. The authors present the case of a 54-year-old female, submitted to laparoscopic adjustable gastric banding in April 2004 (BMI = 40 kg/m(2)). During the first year, she reduced her body mass index to 30 and remained stable thereafter. In August 2008, while investigating a moderate colicky abdominal pain, she was submitted to a colonoscopy that showed part of the band inside the transverse colon. Two exams were performed: the abdominal CT scan, which showed the connecting tube inside the transverse colon lumen and the lap band which was apparently well positioned around the stomach, and an upper digestive endoscopy that revealed band migration to the stomach lumen. The patient underwent laparoscopic band removal and closure of both stomach and colon walls, thus treating the fistula. LAGB erosion and migration is a late complication of this surgery that frequently needs surgical removal. LAGB migration to colon or stomach is described in literature isolated. Simultaneous erosion to stomach and colon lumen, with a gastrocolic fistula formation, has never been described before, making this case a unique one.