A PORTABLE AND INEXPENSIVE DO-IT-YOURSELF TEMPERATURE SENSOR

Nowadays it is important to have commercial solutions to be used in teaching and research laboratories for the needs. We can have different equipment according to the necessary parameters of control being related to the influence of parameters internal or external to the laboratory practice. However they can't be straightforward to use, their costs can be considerable.  In this context, the do-it-yourself approach is an interesting alternative. In this paper we report the construction of a temperature sensor made by students. Based on a probe taken from a deactivated equipment, the sensor development and validation encompassed its design and building up, the establishment of a connection to a personal computer via USB, the setup of computer-controlled processes, which included remote control, graphical and numerical displaying and signal acquisition, and finally its testing. Tests were performed in water containers with different temperatures, namely boiling, room and ice. The obtained results are comparable to those from a commercial thermometer. This student experiment project allowed not only to contact different disciplines such as chemistry, electronics, and programming but also to gain competencies that can be used outside the class context. We proved it is possible to build tailor-made electronic devices capable of providing useful measurements to chemical purposes old equipment in an inexpensive and trustworthy way

Push-out Bond Strength Of Mta Hp, A New High-plasticity Calcium Silicate-based Cement

This study was designed to investigate the resistance to dislodgment provided by MTA HP, a new high-plasticity calcium silicate-based cement. Biodentine and White MTA Angelus were used as reference materials for comparison. Three discs 1 +/- 0.1 mm thick were obtained from the middle third of the roots of 5 maxillary canines. Three 0.8-mm-wide holes were drilled on the axial surface of each root disc. Standardized irrigation was performed. Then the holes were dried with paper points and filled with one of the three tested cements. The filled dental slices were immersed in a phosphate-buffered saline (PBS) solution (pH 7.2) for 7 days before the push-out assessment. The Kruskal-Wallis test was applied to assess the effect of each endodontic cement on the push-out bond strength. Mann-Whitney with Bonferroni correction was used to isolate the differences. The alpha-type error was set at 0.05. All specimens had measurable push-out values and no premature failure occurred. There were significant differences among the materials (p < 0.05). The Biodentine specimens had the highest push-out bond strength values (p < 0.05). MTA HP had significantly higher bond strength than White MTA (p < 0.05). MTA HP showed better push-out bond strength than its predecessor, White MTA; however, Biodentine had higher dislodgment resistance than both MTA formulations.301FAPERJ [E-26/010.001243/2015, E-26/201.491/2014

Cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium hydroxide

This study evaluated the cytotoxicity, antibacterial and physicochemical properties of a new epoxy resin-based endodontic sealer containing calcium-hydroxide Sealer Plus. AH Plus was used as a reference for comparison. Cytotoxicity evaluation was performed according to ISO-10993-5 specifications using MTT assay to check the 3T3 cells viability at 1- to 4-week periods. Antibacterial activity was evaluated using a direct contact test against Enterococcus faecalis. Radiopacity, solubility and flow evaluations were performed according to ISO-6876/2012 specifications. Setting time was assessed following the ANSI/ADA-standard-n.57. The pH level was measured at 3,24,48,72, and 168 hours. Data were statistically analyzed using t-test. The signi?cance level adopted was P0.05). Direct contact results revealed that both freshly prepared sealers has antibacterial effects against Enterococcus faecalis. However, after 7 days both sealers had lost much of their antibacterial effects. Although AH Plus presented higher radiopacity and flow than Sealer Plus (P0.05). AH Plus showed a higher setting time when compared to Sealer Plus (P<0.05). AH Plus and Sealer Plus showed a neutral pH during all tested periods (P<0.05). It can be concluded that Sealer Plus showed suitable properties to be used as an endodontic sealer, comparable with those obtained by AH Plus

A Novel Protocol to Characterize Virtual Nickel–Titanium Endodontic Instruments

Publisher Copyright: © 2023 by the authors.The nickel–titanium (NiTi) instruments’ geometry plays an important role in their performance and behavior. The present assessment intends to validate and test the applicability of a 3D surface scanning method using a high-resolution laboratory-based optical scanner to create reliable virtual models of NiTi instruments. Sixteen instruments were scanned using a 12-megapixel optical 3D scanner, and methodological validation was performed by comparing quantitative and qualitative measurements of specific dimensions and identifying some geometric features of the 3D models with images obtained through scanning electron microscopy. Additionally, the reproducibility of the method was assessed by calculating 2D and 3D parameters of three different instruments twice. The quality of the 3D models created by two different optical scanners and a micro-CT device was compared. The 3D surface scanning method using the high-resolution laboratory-based optical scanner allowed for the creation of reliable and precise virtual models of different NiTi instruments with discrepancies varying from 0.0002 to 0.0182 mm. The reproducibility of measurements performed with this method was high, and the acquired virtual models were adequate for use in in silico experiments, as well as for commercial or educational purposes. The quality of the 3D model obtained using the high-resolution optical scanner was superior to that acquired by micro-CT technology. The ability to superimpose virtual models of scanned instruments and apply them in Finite Element Analysis and educational purposes was also demonstrated.publishersversionpublishe

Forecasting the price of gold

This article seeks to evaluate the appropriateness of a variety of existing forecasting techniques (17 methods) at providing accurate and statistically significant forecasts for gold price. We report the results from the nine most competitive techniques. Special consideration is given to the ability of these techniques to provide forecasts which outperforms the random walk (RW) as we noticed that certain multivariate models (which included prices of silver, platinum, palladium and rhodium, besides gold) were also unable to outperform the RW in this case. Interestingly, the results show that none of the forecasting techniques are able to outperform the RW at horizons of 1 and 9 steps ahead, and on average, the exponential smoothing model is seen providing the best forecasts in terms of the lowest root mean squared error over the 24-month forecasting horizons. Moreover, we find that the univariate models used in this article are able to outperform the Bayesian autoregression and Bayesian vector autoregressive models, with exponential smoothing reporting statistically significant results in comparison with the former models, and classical autoregressive and the vector autoregressive models in most cases

Design, metallurgical characteristics, and mechanical performance

Funding Information: FMBF acknowledges the funding of CENIMAT/i3N by national funds through the FCT‐Fundação para a Ciência e a Tecnologia, I.P., within the scope of Multiannual Financing of R&D Units, reference UIDB/50025/2020‐2023. The authors ackowledge Fernanda Carvalho for running the differential scanning calorimetry tests on the endodontic files. Publisher Copyright: © 2023 The Authors. International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.Aim: To compare two flat-side single-file rotary instruments with three single-file reciprocating systems through a multimethod assessment. Methodology: A total of 290 new NiTi single-file rotary (AF F One Blue 25/0.06 and Platinum V.EU 25/0.06) and reciprocating (One Files Blue R25, Reciproc Blue R25, Reciproc R25) instruments were selected, carefully examined for any major deformations, and evaluated regarding their macroscopic and microscopic design, nickel and titanium elements ratio, phase transformation temperatures, and mechanical performance (time/rotation to fracture, maximum torque, angle of rotation, microhardness, maximum bending, and buckling strengths). One-way anova post hoc Tukey, T-test, and nonparametric Mood's median tests were used for statistical comparisons (α = 5%). Results: Tested instruments had identical blade counts and near-identical helical angles of approximately 24° (rotary instruments) and 151° (reciprocating instruments). The flat-side analysis revealed a few inconsistencies, such as discontinuity segments, different orientations, and gaps in the homogeneity of the bluish colour. Microscopically, flat-side instruments exhibited blade discontinuity and an incomplete S-shaped cross-section. The surface finish was smoother for One Files Blue and more irregular for both rotary instruments. There were distinct phase transformation temperatures amongst all instruments. All heat-treated instruments were in R-phase arrangement, and Reciproc was in R-phase plus austenite at test temperature (20°C). Compared with the reciprocating instruments, both flat-side instruments exhibited lower results in the cyclic fatigue tests using two different clockwise kinematics, maximum torque, angle of rotation, and maximum buckling strength (p <.05). The rotary systems also exhibited low flexibility (p <.05). AF F One Blue had the lowest microhardness, whilst Reciproc had the highest value. Conclusion: This multimethod investigation revealed that the flat-side rotary instruments underperformed the reciprocating instruments regarding cyclic fatigue (with two different clockwise kinematics), maximum torque, angle of rotation, maximum buckling strength, and flexibility. Manufacturing inconsistencies were also observed in some of the flat-side instruments, including discontinuity segments, different orientations, and in the homogeneity of their bluish colour given by the heat treatment.publishersversionpublishe

Rim-to-Rim Wearables at the Canyon for Health (R2R WATCH): Physiological, Cognitive, and Biological Markers of Performance Decline in an Extreme Environment

Success in extreme environments comes with a cost of subtle performance decrements that if not mitigated properly can lead to lifethreatening consequences. Identification and prediction of performance decline could alleviate deleterious consequences and enhance success in challenging and high-risk operations. The Rim-to-Rim Wearables at the Canyon for Health (R2R WATCH) project was designed to examine the cognitive, physiological, and biological markers of performance decline in the extreme environment of the Grand Canyon Rim-to-Rim (R2R) hike. The study utilized commercial off-the-shelf cognitive and physiological monitoring techniques, along with subjective self-assessments and hematologic measurements to determine subject performance and changes across the hike. The multiyear effort collected these multiple data streams in parallel on a large sample of participants hiking the R2R, leading to a rich and complex data set. This article describes the methodology and its evolution as devices and measurements were assessed after each data collection event. It also highlights a subset of the patterns of results found across the data streams. Subsequent work will draw on this data set to focus on building more sophisticated, predictive statistical models and dive deeper into specific analyses (such as the physiological and biological profiles of hikers who were left behind by their hiking partners)

Effect of alginate molecular weight and M/G ratio in beads properties foreseeing the protection of probiotics

"Available online 1 December 2017"Probiotics are live microorganisms that when administered in adequate amounts confer a health benefit to the host. However, to accomplish this positive influence on Human health, probiotics should survive to the passage through the upper digestive tract in large numbers to unsure a desired beneficial effect in the host. Several encapsulation methods have been used to protect probiotics. Alginate is the most used biopolymer in the production of these systems, although its performance is totally dependent of its structure and chemical characteristics. In this work, alginates with different molecular weights and different mannuronic and guluronic acid residues ratio (M/G ratio) were used in the encapsulation of Lactococcus lactis spp. cremoris (LLC) aiming the protection of this probiotic bacteria against the harsh conditions of digestion. Alginate-based beads were produced using an external gelation process (extrusion technique) where variables regarding the processing conditions and alginate chemical characteristics were studied to assess their relevance in this process aiming the most efficient encapsulation system. The most important variables influencing the size of alginate beads were the alginate concentration, alginate type (M/G ratio and molecular weight) and the nozzle diameter. Beads with sizes ranged between 1.9 and 3.0 mm were produced using different alginates. Fourier transform infrared (FTIR) spectroscopy showed relevant differences between beads produced proving the impact of different M/G ratios in the beads chemical structure. In general, low molecular weight and low M/G ratio alginate (Protanal LFR5/60) proved to produce the most well organized (according to SEM analyses), less permeable (pore diameter of 2.52 nm) and stronger alginate beads, moreover molecular weight and M/G ratio proved to be an important variable on the protection of probiotics against the harsh conditions of digestion. Produced beads proved to be efficient in the protection of probiotics (i.e. high viability), with the best performance presented by the medium and low molecular weight alginates.The author Philippe E. Ramos would like to thank the Post-doc fellowship to the national agency Fundação para a Ciência e a Tecnologia (UID/BIO/04469) and to the European Regional Development Fund (FEDER) through COMPETE 2020 e Programa Operacional Competitividade e Internacionalização (POCI-01-0145-FEDER-006684). The authors thank the FCT Strategic Project PEstOE/EQB/LA0023/2013 and the project “BioInddBiotechnology and Bioengineering for Improved Industrial and Agro-Food Processes”, ref. NORTE-07-0124-FEDER-000028 cofunded by the Programa Operacional Regional do Norte (ON.2eO Novo Norte), QREN, FEDER.info:eu-repo/semantics/publishedVersio