Optical Active Meta-Surfaces, -Substrates, and Single Quantum Dots Based on Tuning Organic Composites with Graphene.

In this communication, the design and fabrication of optical active metamaterials were developed by the incorporation of graphene and joining it to different substrates with variable spectroscopical properties. It focuses on how graphene and its derivatives could generate varied optical setups and materials considering modified and enhanced optics within substrates and surfaces. In this manner, it is discussed how light could be tuned and modified along its path from confined nano-patterned surfaces or through a modified micro-lens. In addition to these optical properties generated from the physical interaction of light, it should be added that the non-classical light pathways and quantum phenomena could participate. In this way, graphene and related carbon-based materials with particular properties, such as highly condensed electronics, pseudo-electromagnetic properties, and quantum and luminescent properties, could be incorporated. Therefore, the modified substrates could be switched by photo-stimulation with variable responses depending on the nature of the material constitution. Therefore, the optical properties of graphene and its derivatives are discussed in these types of metasurfaces with targeted optical active properties, such as within the UV, IR, and terahertz wavelength intervals, along with their further properties and respective potential applications.

Poly(N-isopropylacrylamide)-interpenetrated chitosan coils working as nanoreactors for controlled silver nanoparticle growth.

A new precursor (Ag+/CS/PNIPA) arranged as a nanogel (nanoreactor) is obtained from the aqueous mixture of Ag+, chitosan (CS) and poly(N-isopropylacrylamide) (PNIPA). A model synthetic system based on the thermally induced aqueous silver ions-CS reaction to form silver nanoparticles (AgNP) is used as a starting point to assess the PNIPA role as a thermo-sensitive additive of synthesis in a low content for the production of size-controlled AgNP. As expected, the PNIPA phase transition produced by the temperature increase leads to chitosan nanogel contraction, lowering the diffusion of ionic species. PNIPA behaves as a successful additive between 5.6 and 10.5 wt% of content blended with chitosan, noticeably improving AgNP nucleation during thermal treatment at 90 °C. Higher PNIPA contents are less effective in achieving size control and broader size distributions are generated. The PNIPA effect on the nanoreactor structure is characterized by rheology, modelled and analyzed against the AgNP morphology obtained.

Cost Model for Biogas and Biomethane Production in Anaerobic Digestion and Upgrading. Case Study: Castile and Leon.

The increase in pig production is a key factor in the fight against climate change. The main problem is the amount of slurry which causes environmental problems, therefore optimal management is needed. This management consists of an anaerobic digestion process in which biogas is produced and a subsequent upgrading process produces biomethane. In this study, a comparison of different biomethane production systems is completed in order to determine the optimum for each pig farm, determining that conventional upgrading systems can be used on farms with more than 11,000 pigs and, for smaller numbers of pigs, the biological upgrading system. The implementation of these technologies contributes to reducing fossil energy demand and greenhouse gas emissions by using biogas and biomethane as heat, electricity or vehicle fuel.

Presencia de huesos accesorios del tarso: variantes anatómicas normales con potencialidad patológica / Presence of accessory bones of the tarsus: normal anatomical variants with pathological potential / Presença de ossos acessórios do tarso: variantes anatômicas normais com potencial patológico

El conjunto de patologías bajo el nombre de síndromes dolorosos de pie y tobillo engloban diferentes tendinopatías asociadas entre varios factores clínicos a la presencia de huesos accesorios tarsianos. La correcta identificación y diferenciación radiológica de estas variantes anatómicas en virtud de su capacidad de influir en la dinámica normal del tarso motivan el estudio de su incidencia. Nuestro objetivo es determinar la presencia de distintos huesos accesorios tarsianos en una muestra poblacional. Se expone el resultado de un estudio observacional retrospectivo en 240 pacientes entre 15 y 85 años de edad atendidos en un centro privado de la ciudad de Las Piedras, Canelones, con radiografías de pie y tobillo preexistentes en la base de datos institucional. Se determinó presencia de huesos accesorios tarsianos en 23 pacientes (9,58%), identificando hallazgos de Os Trigonum (1,66%), Proceso de Stieda (3.33%), Os Peroneum (2,93%) y Os Navicular (1,66%). Se presenta en tablas el análisis de frecuencia correspondiente y estudio de contingencia entre variantes encontradas, edad y sexo del paciente. El resultado de la investigación busca aportar al conocimiento de variantes anatómicas normales correlativas a procesos patológicos infradiagnosticados, desde el rol de la anatomía radiológica.

The group of pathologies under the name of foot and ankle pain syndromes encompass different tendinopathies associated among various clinical factors with the presence of accessory tarsal bones. The correct identification and radiological differentiation of these anatomical variants, by virtue of their ability to influence the normal dynamics of the tarsus, motivated the study of their incidence. Our objective is to determine the presence of different tarsal accessory bones in a population sample. Here we present the results of a retrospective observational study in 240 patients between 15 and 85 years of age, treated in a private health center in the city of Las Piedras, Canelones, with pre-existing ankle and foot x-rays in the institutional database. The presence of tarsal accessory bones was determined in 23 patients (9.58%), identifying findings of Os Trigonum (1.66%), Stieda Process (3.33%), Os Peroneum (2.93%) and Os Navicular (1, 66%). The corresponding frequency analysis and contingency study between the variants found, age and sex of the patient are exposed in tables. The result of the research seeks to contribute to the knowledge of normal anatomical variants correlative to under diagnosed pathological processes, from the role of radiological anatomy.

O grupo de patologias com a denominação de síndromes dolorosas no pé e tornozelo engloba diferentes tendinopatias associadas entre diversos fatores clínicos à presença de ossos acessórios do tarso. A correta identificação e diferenciação radiológica dessas variantes anatômicas em virtude de sua capacidade de influenciar a dinâmica normal do tarso motiva o estudo de sua incidência. Nosso objetivo é determinar a presença de diferentes ossos acessórios do tarso em uma amostra populacional. É apresentado o resultado de um estudo observacional retrospectivo em 240 pacientes entre 15 e 85 anos de idade atendidos em um centro privado na cidade de Las Piedras, Canelones, com radiografias de pé e tornozelo pré-existentes no banco de dados institucional. A presença de ossos acessórios do tarso foi determinada em 23 pacientes (9,58%), identificando achados de Os Trigonum (1,66%), Processo de Stieda (3,33%), Os Peroneum (2,93%) e Os Navicular (1,66%). A correspondente análise de frequência e estudo de contingência entre as variantes encontradas, idade e sexo do paciente são apresentados em tabelas. O resultado da pesquisa busca contribuir para o conhecimento das variantes anatômicas normais correlativas aos processos patológicos subdiagnosticados, a partir do papel da anatomia radiológica.

Smart material based on boron crosslinked polymers with potential applications in cancer radiation therapy.

Organoboron compounds have been playing an increasingly important role in analytical chemistry, material science, health applications, and particularly as functional polymers like boron carriers for cancer therapy. There are two main applications of boron isotopes in radiation cancer therapy, Boron Neutron Capture Therapy and Proton Boron Fusion Therapy. In this study, a novel and original material consisting of a three-dimensional polymer network crosslinked with [Formula: see text]B enriched boric acid molecules is proposed and synthesized. The effects of the exposition to thermal neutrons were studied analyzing changes in the mechanical properties of the proposed material. Dedicated Monte Carlo simulations, based on MCNP and FLUKA main codes, were performed to characterize interactions of the proposed material with neutrons, photons, and charged particles typically present in mixed fields in nuclear reactor irradiations. Experimental results and Monte Carlo simulations were in agreement, thus justifying further studies of this promising material.

A microfluidic actuator based on a stimuli-responsive hydrogel grafted into Cucurbita moschata xylems.

A chemical actuator was developed taking advantage of the internal microstructure of a plant stem. Stem xylems of Cucurbita moschata were chemically modified with a pH-responsive polymer to obtain an intelligent hydraulic valve. The chemical composition of the device was based mainly on biological scaffolds combined with a minimum content of a tailor-made synthetic copolymer. A pH-sensitive hydrogel composed of a copolymer of acrylic acid was grafted on the inner surface of stem microchannels, assessing the physicochemical properties and the response of the developed actuator under different pressure and pH conditions. Variation of average microcapillary diameter in response to pH stimuli was estimated using Poiseuille's model. This microfluidic device demonstrated the pH-responsive properties and efficient control of flux, showing its open/close transition at pH 3.25 and mechanical stability until pressures of 1.75 meters of water column (mH2O). This actuator has adequate response to open/close cycling and relevance to be evaluated as a pH-response valve of aqueous systems. This kind of actuator is a research topic of high interest with potential application to technology demands.

Dose-response of Fricke- and PAGAT-dosimetry gels in kilovoltage and megavoltage photon beams: Impact of LET on sensitivity.

PURPOSE: Dosimetry of ionizing radiation quantifies the energy deposited by an incident beam to the medium. This study presents the relative response of two types of gel dosimeters describing their differences by estimating radiation chemical yields produced in water radiolysis. METHODS: Two types of gel dosimeter were used, namely an acid ferrous ion solution infused with xylenol orange known as Fricke gel and a polymer gel based on acrylamide and N,N'-methylenebis(acrylamide) known as PAGAT. Samples were irradiated using two photon beam energies, one from a conventional X-ray tube operated at 44 kV and the other one from a LINAC operated at 6 MV. The dosimeters were analyzed by optical absorbance and magnetic resonance imaging. Additionally, the linear energy transfer of each beam was calculated using Monte Carlo simulations for further estimation of the radiation chemical yields produced during water radiolysis. RESULTS: Obtained results for both gel dosimeters indicate that their response at 44 kV and 6 MV are different, regardless of the read-out technique. On average, the sensitivity at 44 kV was found to be 65 % of the response at 6 MV. The calculated radiation chemical yields are in agreement with the observed experimental results. CONCLUSIONS: The main reason for the difference in the response of the dosimeters may be related to the linear energy transfer of each photon beam, which varies the production of primary chemical species during water radiolysis.

Controlled Thermoreversible Formation of Supramolecular Hydrogels Based on Poly(vinyl alcohol) and Natural Phenolic Compounds.

Supramolecular hydrogels have promising applications in a wide variety of fields including 3D bioprinting, sensors and actuators, biomedicine, and controlled drug delivery. This communication reports the facile reversible thermotriggered formation of novel pH-responsive supramolecular hydrogels based on poly(vinyl alcohol) (PVA) bonded via dynamic H-bridge with small phenolic biomolecules. PVA and phenolic compounds form a clear solution when they are physically mixed in water at high temperature, but a fast gelation is produced at room temperature through multiple strong H-bonding interactions. The structure and type of functional groups of different phenolic molecules allow preparing hydrogels with tailor-made viscoelastic properties, controlled low phase transition temperature, and pH-dependent swelling behavior. This combination makes these supramolecular networks very interesting candidates to be used in 3D bioprinting and topical drug delivery of thermolabile biomolecules.

Hybrid approach for automatic cephalometric landmark annotation on cone-beam computed tomography volumes.

INTRODUCTION: Cone-beam computed tomography (CBCT) is commonly used for 3-dimensional (3D) evaluation and treatment planning of patients in orthodontics, where precision and reproducibility of landmark annotation are required. Manual landmarking is a time- and effort-consuming task regardless of the practitioner's experience. We introduce a hybrid algorithm for automatic cephalometric landmark annotation on CBCT volumes. METHODS: This algorithm is based on a 2-dimensional holistic search using active shape models in coronal and sagittal related projections followed by a 3D knowledge-based searching algorithm on subvolumes for local landmark adjustment. Eighteen landmarks were located on 24 CBCT head scans from a public dataset. RESULTS: A 2.51-mm mean localization error (SD, 1.60 mm) was achieved when comparing automatic annotations with ground truth. CONCLUSIONS: The proposed hybrid algorithm shows that a fast initial 2-dimensional landmark search can be useful for a more accurate 3D annotation and could save computational time compared with a full-volume analysis. Furthermore, this study shows that full bone structures from CBCT are manageable in a personal computer for 3D modern cephalometry.

Mucin and carbon nanotube-based biosensor for detection of glucose in human plasma.

This work reports an amperometric enzyme-electrode prepared with glucose oxidase, which have been immobilized by a cross-linking step with glutaraldehyde in a mixture containing albumin and a novel carbon nanotubes-mucin composite (CNT-muc). The obtained hydrogel matrix was trapped between two polycarbonate membranes and then fixed at the surface of a Pt working electrode. The developed biosensor was optimized by evaluating different compositions and the analytical properties of an enzymatic matrix with CNT-muc. Then, the performance of the resulting enzymatic matrix was evaluated for direct glucose quantification in human blood plasma. The novel CNT-muc composite provided a sensitivity of 0.44 ±â€¯0.01 mA M-1 and a response time of 28 ±â€¯2 s. These values were respectively 20% higher and 40% shorter than those obtained with a sandwich-type biosensor prepared without CNT. Additionally, CNT-muc based biosensor exhibited more than 3 orders of magnitude of linear dynamic calibration range and a detection limit of 3 µM. The short-term and long-term stabilities of the biosensors were also examined and excellent results were obtained through successive experiments performed within the first 60 days from their preparation. Finally, the storage stability was remarkable during the first 300 days.

Automatic 3-dimensional cephalometric landmarking based on active shape models in related projections.

INTRODUCTION: This article presents a novel technique for automatic cephalometric landmark localization on 3-dimensional (3D) cone-beam computed tomography (CBCT) volumes by using an active shape model to search for landmarks in related projections. METHODS: Twenty-four random CBCT scans from a public data set were imported and processed into Matlab (MathWorks, Natick, Mass). Orthogonal coronal and sagittal projections (digitally reconstructed radiographs) were created, and 2 trained active shape models were used to locate cephalometric landmarks on each. Finally, by relating projections, 18 tridimensional landmarks were located on CBCT volume representations. RESULTS: From our 3D gold standard, a 3.64-mm mean error in localization of cephalometric landmarks was achieved with this method, with the highest localization errors in the porion and sella regions because of the low volume definition. CONCLUSIONS: The proposed algorithm for automatic 3D landmarking on CBCT volumes seems to be useful for 3D cephalometric analysis. This study shows that a fast 2-dimensional landmark search can be useful for 3D localization, which could save computational time compared with a full-volume analysis. Also, this research confirms that by using CBCT for cephalometry, there are no distortion projections, and full structure information of a virtual patient is manageable in a personal computer.

Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters.

Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution in diagnostic and therapeutic medical applications. But, even in systems where the 3D structure is usually maintained for long periods of time after irradiation, it is still not possible to eliminate the diffusion of the different species in the regions of dose gradients within the gel. As a consequence, information of the dose loses quality over time. In the pursuit of a solution and to improve the understanding of this phenomenon a novel system based on itaconic acid and N-N'-methylene-bisacrylamide (BIS) is hereby proposed. Effects of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species was studied. In this study, one of the carboxylic groups of the itaconic acid molecule was modified with aniline to obtain molecules with similar reactivity but different molecular sizes. Then, dosimeters based on these modified species and on the original ITA molecules were irradiated in an X-ray tomography apparatus at different doses up to 173Gy. Afterwards, the resulting dosimeters were characterized by Raman spectroscopy and optical absorbance in order to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the post irradiation diffusion.

Spectroscopic behavior of loratadine and desloratadine in different aqueous media conditions studied by means of TD-DFT calculations.

In this study, we explained the influence of the stepwise protonation of two antihistaminic drugs on their experimental absorption spectra. We demonstrated the capability of the TD-CAM-B3LYP method, combined with a polarizable continuum model, to produce good performance for the calculated spectra. The lowest energy transitions and the molecular orbital plots were analyzed in detail. The calculated UV spectra are proposed as potential alternatives to initialize the well-known MCR-ALS algorithm, especially when the spectra of the pure analytes are not available. Moreover, it can be a useful strategy for planning an experimental methodology oriented to multiway analysis when the drug species exhibit acid-base properties.

Amperometric biosensor for direct blood lactate detection.

An amperometric sensor for lactate quantification is presented. The developed biosensor requires only 0.2 U of lactate oxidase, which is immobilized in a mucin/albumin hydrogel matrix. By protecting the platinum surface with a Nafion membrane, typical interference related to negatively charged species such as ascorbic acid has been minimized to practically undetectable levels. Electrochemical properties associated with the Nafion membrane are assessed as a function of Nafion concentration. In a phosphate buffer solution of pH 7.0, linear dependence of the catalytic current upon lactate bulk concentration was obtained between 2 and approximately 1000 microM. A detection limit of 0.8 microM can be calculated considering 3 times the standard deviation of the blank signal divided by the sensitivity of the sensor. The lactate biosensor presents remarkable operational stability and sensitivity (0.537 +/- 0.007) mA.M(-1), where the error is the standard deviation of the slope calculated from the linear regression of the calibration curve of a fresh biosensor. In this regard, the sensor keeps practically the same sensitivity for 5 months, while the linear range decreases until an upper value of 0.8 mM is reached. Assays performed with whole blood samples spiked with 100 microM lactate gave (89 +/- 6)% of recovery.

Self-measurement of blood pressure: validation of the Braun BP VitalScan Plus 1650 monitor according to the European Society of Hypertension International Protocol.

BACKGROUND: Self-measurement of blood pressure (BP) has been increasingly encouraged as a supplement to measurements in the clinic. OBJECTIVE: The main objective of this study is to clinically evaluate a new device for self-measurement of BP according to the International Protocol of the European Society of Hypertension (2002). METHODS: Measurements of systolic and diastolic BP in 33 volunteers (15 for phase 1 and a further 18 for phase 2 providing 99 measurements) were obtained using the mercury sphygmomanometer (HgS; Baumanometer) and the Braun BP VitalScan Plus 1650 device. Nine sequential same-arm measurements between the test device and the standard HgS were carried out according to the International Protocol of the European Society of Hypertension in two phases (phase 1, phase 2.1 and phase 2.2). RESULTS: The device passed phase 1 as 30 systolic and 33 diastolic readings fell within 5 mmHg exceeding the 25 required. In addition, the equipment also passed phase 2.1 as 74 systolic and 77 diastolic readings fell within 5 mmHg exceeding the 65 required for being approved. Finally, it also passed the phase 2.2 as 25 volunteers for systolic and 28 for diastolic had at least 2/3 of their comparisons falling within 5 mmHg (exceeding the 22 required) and only two of the 33 volunteers had their three comparisons over 5 mmHg apart (at the most three are required). The difference-against-mean plots showed that the disagreement between the HgS and the device was -2.57+/-4.36 mmHg for systolic BP and +0.83+/-4.97 mmHg for diastolic BP, respectively. CONCLUSION: The equipment passed the different phases satisfactorily and the study suggests that it can be used for self-BP monitoring. The device, however, needs to be used with care by the patients following the instructions, because even when it may be accurate in a laboratory setting, there is potential for them to be used inaccurately in the home setting.

Clinical evaluation of the Braun BP 3000 Easy Click according to the ANSI/AAMI SP 10:2002.

BACKGROUND: Home blood pressure monitoring has been increasingly encouraged as a supplement to measurements in the clinic in the 2003 European Society of Hypertension-European Society of Cardiology and in the Seventh Joint National Committee guidelines. Before marketing, however, blood pressure measuring devices for self-blood pressure monitoring should be independently validated. OBJECTIVE: The main objective of the present study was to examine the clinical accuracy of the Braun BP 3000 (Braun GmbH, Kronberg, Germany) wrist blood pressure measurement device. METHODS: Measurements of systolic and diastolic blood pressure in normotensive and hypertensive individuals were obtained using the mercury sphygmomanometer and the Braun BP 3000 equipment. Repeated sequential blood pressure single-arm measurements comparing the test device and the standard mercury sphygmomanometer were completed according to the American National Standard Institution (ANSI)/Association for the Advancement of Medical Instrumentation (AAMI) SP 10:2002 Protocol Guidelines on 90 study participants (270 measurements with each pressurometer). RESULTS: The equipment passed the test of systolic blood pressure measurements for method 1 (270 measurements treated separately) and method 2 (mean values of three observations on 90 patients). The mean+/-SD value was -2.01+/-5.61 (upper limit 5+/-8) and -2.01+/-4.41 (upper limit 2.01+/-6.65), respectively. The device also passed the diastolic blood pressure measurement requirements as the mean+/-SD value for method 1 was -0.97+/-5.52 (upper limit 5+/-8) and for method 2 was -0.97+/-4.87 (upper limit 0.97+/-6.87), respectively. CONCLUSIONS: The data from this study show that the Braun BP 3000 successfully passed the ANSI/AAMI SP 10:2002 requirements.

Home blood pressure measurement: validation of the Braun BP 2550 (UG) monitor according to the ESH International Protocol.

BACKGROUND: The Sixth Report of the Joint National Committee states that the 'measurement of blood pressure outside the clinician's office may provide valuable information for the initial evaluation of patients with hypertension and for monitoring the response to treatment'. Prior to their marketing, however, blood pressure measuring devices should be independently validated for safety and accuracy using standard guidelines. OBJECTIVE: The main objective of the present study was the clinical evaluation of the Braun Precision Sensor 2550 upgrade (Braun BP 2550 (UG)) according to the International Protocol of the European Society of Hypertension (ESH). METHODS: Measurements of systolic and diastolic blood pressure in 33 subjects were obtained using the mercury sphygmomanometer (Baumanometer) and the device. The sizes of the cuffs used for different arm circumferences were 12 x 23 cm, 15 x 33 cm and 18 x 36 cm for the thin adult, adult and overweight adult, respectively. The adult size was mostly used. If the cuff of the sphygmomanometer did not fall between the two range lines, a larger or smaller cuff was required. The reproducibility of self-blood pressure measurement was compared in 33 subjects (99 measurements). Nine sequential same-arm measurements comparing the test device and the standard mercury sphygmomanometer were carried out according to the International Protocol of the ESH in three steps (phases 1, 2.1 and 2.2). RESULTS: The device passed phases 1 and 2.1 as 75 systolic and 78 diastolic readings fell within 5 mmHg, exceeding the total of 65 required for approval. It also passed phase 2.2 as 30 subjects for systolic and 29 for diastolic had at least two out of three comparisons within 5 mmHg, exceeding the 22 subjects required. The difference-against-mean plots showed that the device-sphygmomanometer disagreement was -1.58+/-4.84 for systolic pressure (the Braun being lower) and +2.23+/-3.84 for diastolic pressure (the Braun being higher), respectively. CONCLUSIONS: The equipment passed both phases of the International Protocol (subject measurements and subject accuracy). The difference of 0-5 mmHg between the sphygmomanometer and the device represents 'measurements considered to be very accurate and with no error of clinical relevance'. It can therefore be used at home as an adjunct to physicians' effort to control blood pressure in their hypertensive patients.