Study of Mechanical Response of Paper-Based Microfluidic System as a Potential Milk Tester.

Milk is considered a complete meal that requires supervision to determine its suitability for human consumption. The development of sustainable devices that evaluate food properties has gained importance due to the necessity of integrating these instruments into the production chain. However, the materials employed to develop it, such as polymers, semiconductors, and glass, lack sustainability and require specialized equipment to fabricate them. Different chemical techniques have been used to miniaturize these detection systems such as microfluidics, which have been used in milk component detection using colorimetry. In this work, a cantilever beam paper-based microfluidic system is proposed to evaluate differences in milk, according to nutritional information, using its electromechanical response. A 20-microliter milk drop is deposited in the system, which induces hygroexpansion and deflection due to liquid transport within the paper. Likewise, a conductive path is added on the beam top surface to supply a constant current that induces heat to evaporate the solution. According to the results obtained, it is possible to point out differences between trademarks with this microfluidic system. The novelty of this system relies on the paper electromechanical response that integrates the hygroexpansion-induced displacement, which can be used for further applications such as milk microtesters instead of colorimetric tests that use paper as a property-evaluation platform in combination with chemical reactions.

First Apatite (U-Th)/He and apatite fission-track thermochronology dataset from the Abancay Deflection (Eastern Cordillera, Southern Peru).

According to their respective temperature sensitivities, Apatite (U-Th)/He (AHe) and apatite fission-track (AFT) thermochronology records the thermal evolution of the upper crust (<5 km) and is a key for distinguishing between different exhumation mechanisms through time-evolving rock uplift, and landscape evolution. We applied these methods to extract the thermal evolution of the upper crust in the Abancay Deflection at the northern edge of the Altiplano (southern Peru). We present 120 single-crystal AHe ages (from 31 samples) and 27 AFT central ages obtained from magmatic bodies across the study area. AHe ages range from 0.6 ± 0.1 to 35.8 ± 2.9 Ma with a satisfactory reproducibility of single-crystal AHe ages with less than 10% averaged dispersion. AFT ages range from 2.6 ± 1.9 to 38.2 ± 4.4 Ma with P( χ 2) values >5%. This dataset allows exploring the crust evolution from the late-Eocene to the Quaternary. Data processed and interpreted in the related article published in Tectonics[6] are stored in PANGAEA repository (108 AHe single-grain ages and 27 AFT ages). We furthermore present in this article 12 extra single-grain AHe ages obtained after the related article publication. We also present the details of fission-track length measurements published in the related article. Thermochronological ages could be reused for testing He diffusion or fission track annealing processes or investigating the broader tectonic/geodynamic evolution of the Andes.

The Effect of a Pace Training Session on Internal Load and Neuromuscular Parameters in Taekwondo Athletes.

This study aimed to verify the effect of a pace training session at an intensity corresponding to the kick frequency at the anaerobic threshold (KFAT) on the internal load response and motor response performance of the roundhouse kick. Twelve black belt taekwondo athletes underwent two evaluation sessions: (1) performed the progressive specific test for taekwondo (PSTT) to identify the heart rate deflection point (HRDP) and the KFAT; (2) performed three 2-min rounds with a 1-min interval. Heart rate (HR) throughout each round and motor response performance before and after sessions were measured. The Student's T-test or Wilcoxon test was used, and p < 0.05 was adopted. During round 1, a lower internal load was observed (167 ± 10 bpm) compared with HRDP (179 ± 8 bpm; p = 0.035). During rounds 2 (178 ± 10 bpm; p = 0.745) and 3 (179 ± 8 bpm; p = 1), no differences were observed for an internal load and HRDP. Motor response performance showed no differences. However, a potentiation in the post countermovement jump test compared with rounds 1 (p = 0.012) and 2 (p = 0.028) was observed. The internal load (HR) observed at the intensity corresponding to KFAT can be considered in the prescription of training when the aim is to control the internal load responses without inducing fatigue.

Deflexión de agujas dentales 30G: comparación de cinco marcas comerciales / Deflection of dental needles 30G: comparison of five trademarks

Abstract Introducción: El grado o nivel de deflexión de la aguja dental, en la mayoría de los casos, puede determinar el éxito o fracaso en la técnica de anestesia dental. Objetivo: Medir el grado de deflexión de la aguja dental, comparando 5 diferentes marcas disponibles en la ciudad de Hermosillo, Sonora, México. Métodos: Se realizó un estudio experimental, en el que con ayuda de un modelo creado con un nivel profesional y una jeringa tipo cárpul, se realizaron diversas punciones en un trozo de carne de res, simulando la realización de una técnica lineal de anestesia bucodental. Se tomaron radiografías periapicales de cada una de las punciones, y con ayuda de una malla milimetrada, se realizaron las mediciones. Dentro de cada grupo de agujas, se presentaron diferentes medidas de deflexión, y se obtuvo un promedio de cada marca. El rango abarcó desde los .65 mm hasta 2.1 mm de deflexión, tomando como referencia un plano recto. Conclusiones: Se demostró que la de la marca Septodont®, fue la que presentó menor deflexión a la punción. Es recomendable verificar y examinar el estado de las agujas antes de ser utilizadas para realizar procesos quirúrgicos, y así disminuir riesgos y/o complicaciones postoperatorias.

Resumen Introduction: The degree or level of deflection of the dental needle, in most cases, can determine the success or failure of the dental anesthesia technique. Objective: Measure the degree of deflection of the dental needle, comparing 5 different brands available in the city of Hermosillo, Sonora, Mexico. Method: An experimental study was carried out, with a model created with a professional level and a carpul syringe, various punctures were made in a piece of beef, simulating the performance of a linear technique of oral anesthesia. Periapical radiographs of each of the punctures were taken, and with the help of a millimeter mesh, measurements were made. Within each group of needles, different deflection measures were presented, and an average of each brand was obtained. The range ranged from .65 mm to 2.1 mm of deflection, taking as reference a straight plane. Conclusions: It was shown that the Septodont® brand was the one that presented the lowest puncture deflection. It is advisable to verify and examine the condition of the needles before being used to perform surgical procedures, and thus reduce risks and / or postoperative complications.

Effect of the restorative technique on load-bearing capacity, cusp deflection, and stress distribution of endodontically-treated premolars with MOD restoration.

OBJECTIVES: To evaluate the influence of the restorative technique on the mechanical response of endodontically-treated upper premolars with mesio-occluso-distal (MOD) cavity. MATERIALS AND METHODS: Forty-eight premolars received MOD preparation (4 groups, n = 12) with different restorative techniques: glass ionomer cement + composite resin (the GIC group), a metallic post + composite resin (the MP group), a fiberglass post + composite resin (the FGP group), or no endodontic treatment + restoration with composite resin (the CR group). Cusp strain and load-bearing capacity were evaluated. One-way analysis of variance and the Tukey test were used with α = 5%. Finite element analysis (FEA) was used to calculate displacement and tensile stress for the teeth and restorations. RESULTS: MP showed the highest cusp (p = 0.027) deflection (24.28 ± 5.09 µm/µm), followed by FGP (20.61 ± 5.05 µm/µm), CR (17.72 ± 6.32 µm/µm), and GIC (17.62 ± 7.00 µm/µm). For load-bearing, CR (38.89 ± 3.24 N) showed the highest, followed by GIC (37.51 ± 6.69 N), FGP (29.80 ± 10.03 N), and MP (18.41 ± 4.15 N) (p = 0.001) value. FEA showed similar behavior in the restorations in all groups, while MP showed the highest stress concentration in the tooth and post. CONCLUSIONS: There is no mechanical advantage in using intraradicular posts for endodontically-treated premolars requiring MOD restoration. Filling the pulp chamber with GIC and restoring the tooth with only CR showed the most promising results for cusp deflection, failure load, and stress distribution.

False head complexity and evidence of predator attacks in male and female hairstreak butterflies (Lepidoptera: Theclinae: Eumaeini) from Mexico.

In many butterfly species, the posterior end of the hindwings of individuals perching with their wings closed resembles a butterfly head. This "false head" pattern is considered an adaptation to deflect predator attacks to less vulnerable parts of the body. The presence of symmetrical damage in left and right wings is considered evidence of failed predator attacks to perching butterflies. In this research, we tested the prediction derived from the deflection hypothesis that the degree of resemblance of the false head area (FH) to a real head, as measured by the number of FH "components" (eyespots, "false antennae", modified outline of the FH area and lines converging on the FH area) present in the hindwings, is positively correlated to the frequency of symmetrical damage in the FH area. We studied specimens from two scientific collections of butterflies of the subfamily Theclinae (Lycaenidae) belonging to the Universidad Nacional Autónoma de México (Colección Nacional de Insectos [CNIN] and Museo de Zoología, Facultad de Ciencias [MZFC]). We scored the presence of symmetrical damage in a sample of 20,709 specimens (CNIN: 3,722; MZFC: 16,987) from 126 species (CNIN: 78 species; MZFC: 117 species; 71 species shared by both collections) whose hindwings vary in the number of FH components, and found that, as predicted, the proportion of specimens with symmetrical damage increases as the number of FH components increases. We also tested the hypothesis that behavioural differences between the sexes makes males more prone to receive predator attacks and, thus, we predicted a higher frequency of symmetrical damage in the FH of males than in that of females. We found that the frequency of symmetrical damage was not significantly different between males and females, suggesting that behavioural differences between the sexes produce no differences in the risk of being attacked. Overall, our results provide support to the idea that the FH of butterflies is an adaptation that deflects predator attacks to less vulnerable parts of the body in both sexes.

Heart rate deflection point as an alternative to determining the anaerobic threshold in dyslipidaemic patients

Aim: The aim of the present study was to verify the agreement between the ventilatory method (VT) and the alternative method of heart rate deflection point (HRDP) in determining the anaerobic threshold (AT) during incremental treadmill test in dyslipidaemic patients. Methods: Twenty-seven dyslipidaemic patients (61.50 ± 10.46 years) performed an incremental treadmill test, in which the AT was determined using both methods. Bland-Altman statistics was adopted in order to verify the agreement between the methods. Results: Agreement in AT determination between the VT and HRDP methods was observed (p < 0.05) for heart rate (138.00 ± 23.80 and 136.26 ± 22.18 bpm, respectively), oxygen uptake (31.00 ± 10.33 and 31.00 ± 11.17 ml.kg−1.min−1), and treadmill velocity (7.67 ± 1.71 km.h-1and 8.00 ± 1.75 km.h-1). Conclusion: Our results suggest that the HRDP method can be adopted for the determination of the AT in dyslipidaemic patients, showing agreement with the VT method.(AU)

Deflexión de agujas dentales 30G: comparación de cinco marcas comerciales

Introducción: El grado o nivel de deflexión de la aguja dental, en la mayoría de los casos, puede determinar el éxito o fracaso en la técnica de anestesia dental. Objetivo: Medir el grado de deflexión de la aguja dental, comparando 5 diferentes marcas disponibles en la ciudad de Hermosillo, Sonora, México. Métodos: Se realizó un estudio experimental, en el que con ayuda de un modelo creado con un nivel profesional y una jeringa tipo cárpul, se realizaron diversas punciones en un trozo de carne de res, simulando la realización de una técnica lineal de anestesia bucodental. Se tomaron radiografías periapicales de cada una de las punciones, y con ayuda de una malla milimetrada, se realizaron las mediciones. Dentro de cada grupo de agujas, se presentaron diferentes medidas de deflexión, y se obtuvo un promedio de cada marca. El rango abarcó desde los .65 mm hasta 2.1 mm de deflexión, tomando como referencia un plano recto. Conclusiones: Se demostró que la de la marca Septodont®, fue la que presentó menor deflexión a la punción. Es recomendable verificar y examinar el estado de las agujas antes de ser utilizadas para realizar procesos quirúrgicos, y así disminuir riesgos y/o complicaciones postoperatorias.

Introduction: The degree or level of deflection of the dental needle, in most cases, can determine the success or failure of the dental anesthesia technique. Objective: Measure the degree of deflection of the dental needle, comparing 5 different brands available in the city of Hermosillo, Sonora, Mexico. Method: An experimental study was carried out, with a model created with a professional level and a carpul syringe, various punctures were made in a piece of beef, simulating the performance of a linear technique of oral anesthesia. Periapical radiographs of each of the punctures were taken, and with the help of a millimeter mesh, measurements were made. Within each group of needles, different deflection measures were presented, and an average of each brand was obtained. The range ranged from .65 mm to 2.1 mm of deflection, taking as reference a straight plane. Conclusions: It was shown that the Septodont® brand was the one that presented the lowest puncture deflection. It is advisable to verify and examine the condition of the needles before being used to perform surgical procedures, and thus reduce risks and / or postoperative complications.

R-Peak Time: An Electrocardiographic Parameter with Multiple Clinical Applications.

In the 12-lead electrocardiogram (ECG), the time from the onset of the QRS complex (Q or R wave) to the apex or peak of R or to R' (when present), using indirect or semidirect surface unipolar precordial leads, bipolar limb leads or unipolar limb leads, is called ventricular activation time (VAT), R wave peak time (RWPT), R-peak time or intrinsicoid deflection (ID). The R-peak time in a specific ECG lead is the interval from the earliest onset of the QRS complex, preferably determined from multiple simultaneously recorded leads, to the peak (maximum) of the R wave or R' if present. Irrespective of the relative height of the R and R' waves, the R-peak time is measured to the second peak. The parameter corresponds to the time of the electrical activation occurring from the endocardium to the epicardium as reflected by the recording electrode located at a variable distance on the body surface, depending on the lead type: a unipolar precordial lead, a bipolar or unipolar limb lead. In normal conditions, the R-peak time for the thinner-walled right ventricle is measured from lead V1 or V2 and its upper limit of normal is 35 ms. The R-peak time for the left ventricle (LV) is measured from leads V5 to V6 and 45 ms is considered the upper limit of normal. In this manuscript, we review the clinical applications of this parameter.

Influencia de los cambios térmicos en la deflexión transversa de acrílicos para la base de dentaduras con y sin insertos metálicos / Influence exerted by thermal changes in the transverse deflection of acrylic materials used for denture bases, with and without metallic inserts

El propósito de este estudio in vitro fue determinar si los cambios térmicos influyen en la deflexión transversa de dos diferentes marcas de acrílico para la base de dentaduras con y sin insertos metálicos, después de ser sometidos a un periodo de termociclado con cambios de temperatura. Se elaboraron 40 muestras de acrílico de acuerdo con la especificación no. 12 de la ADA; y se conformaron cuatro grupos, dos de Lucitone 199 y dos de ProBase Hot. Los resultados se sometieron al análisis estadístico ANOVA de una vía y comparación de grupos Tukey con un valor de p < .001. Conclusión: Ambos acrílicos para la base de dentadura cumplen con las especificaciones de la norma no. 12 de la ADA. Los insertos metálicos permiten disminuir la deflexión de los acrílicos y los cambios térmicos afectan de manera considerable las propiedades físicas.

The aim of the present in vitro study was to determine whether thermal changes influence the transverse deflection of two different brands of acrylic used for denture bases, with and without metallic inserts, after having been subjected to a thermo-cycling period with temperature changes. 40 acrylic samples were processed according to ADA's specification number 12. Four groups were made up, two with Lucitone 199 and two with ProBase Hot. Results were subjected to one-way ANOVA statistical analysis and comparison of Turkey groups with a value of (p > .001). Conclusion: Both acrylic materials used for denture bases fulfill specifications of ADA's norm number 12. Metallic inserts allowed the decrease of the acrylic deflection and thermal changes considerably affected physical characteristics.

Stress amplifications in dental non-carious cervical lesions.

This study aims to investigate the influence of the presence, shape and depth of NCCLs on the mechanical response of a maxillary second premolar subjected to functional and non-functional occlusal loadings using 3-D finite element (FE) analysis. A three-dimensional model of a maxillary second premolar and its supporting bone was constructed based on the contours of their cross-sections. From the sound model, cervical defects having either V- or U-shapes, as found clinically, were subtracted in three different depths. The models were loaded with 105 N to simulate normal chewing forces according to a functional occlusal loading (F1) vertically applied and two non-functional loadings (F2 and F3) obliquely oriented. Two alveolar bone crest heights were tested. Ansys™ FE software was used to compute stress distributions and maximum principal stress for each of the models. The presence of a lesion had no effect on the overall stress distribution of the system, but affected local stress concentrations. Non-functional loadings exhibited tensile stresses concentrating at the cervical areas and root surfaces, while the functional loading resulted in homogeneous stress distributions within the tooth. V-shaped lesions showed higher stress levels concentrated at the zenith of the lesion, whereas in U-shaped defect stresses concentrated over a wider area. As the lesions advanced in depth, the stress was amplified at their deepest part. A trend of stress amplification was observed with decreasing bone height. These results suggest a non-linear lesion progression with time, with the progression rate increasing with patient's age (deeper lesions and lower bone support).

Deflexión transversa de materiales alternativos a base de polímeros para fabricación de base de dentadura / Transverse deflection of polymer-based alternative materials for the manufacturing of a denture base

En la actualidad se están desarrollando técnicas alternativas para la fabricación en tiempos cortos de prótesis totales en relación con la utilización de diferentes materiales para la base de dentadura. El propósito de este estudio fue comparar la deflexión transversa entre materiales a base de polímeros, propuestos como una alternativa a los materiales comúnmente utilizados para realizar una prótesis total en forma convencional. Se probaron resina acrílica termocurable, resina acrílica autocurable, láminas de acetato calibre 60 y 80 recubiertas con resina acrílica autocurable, resina acrílica fluida y resina fotopolimerizable para base de dentadura. Se fabricaron diez muestras de 65 x 10 x 2.5 mm de cada material. Las muestras se colocaron en agua a 37°C por 50 horas, se midió la deflexión transversa y se analizaron los resultados por análisis de varianza (ANOVA) de una vía. Los resultados mostraron que hubo diferencia estadísticamente significativa entre los grupos. Las láminas de acetato recubiertas con acrílico autocurable pueden ser una alternativa para la rápida fabricación de bases de dentadura de uso temporal.

Nowadays, alternative techniques are being developed for short-time manufacturing of full prostheses, entailing different materials for the denture base. The purpose of the present study was to compare transverse deflection among polymer-based materials currently proposed as an alternative to materials commonly used to conventionally manufacture a full prosthesis. For the denture base the following materials were tested: thermo-cured (setting) acrylic resin, self-cured acrylic resin, 60 and 80 gauge acetate sheets coated with self-cured acrylic resin, liquid (fluid) acrylic resin as well as light-cured resin. Ten 65 x 10 x 2.5 mm samples of each material were manufactured. The samples were placed in water at 37°C for 50 hours. Transverse deflection was measured and results were analyzed with the help of one-way analysis of variance (ANOVA). Results exhibited statistically significant differences among groups. Acetate sheets coated with self-cured acrylic could represent an alternative for the rapid manufacturing of temporary denture basis.