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1.
Acta Odontol Latinoam ; 37(1): 40-44, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38920125

ABSTRACT

Coloured compounds (anthocyanins) in açaí can stain resin-modified glass-ionomer cement (RMGIC) due to its low staining resistance. AIM: The aim of this study was to assess whether açaí compromises the surface colour and roughness of RMGIC in vitro. MATERIALS AND METHOD: Disc-shaped specimens (2 mm thick, 8 mm in diameter) of Vitremer™ (3M ESPE, St Paul, MN, USA) were prepared according to the manufacturer 's instructions. The mixture was inserted into a silicone mouldplaced between two mylar strips, and light cured. Specimens were randomly divided into three groups (n=25) according to the solutions to be used for chemical degradation: artificial saliva (control), açaí sorbet and açaí juice. A spectrophotometer CM-2600d/2500d (Konica Minolta, Tokyo, Japan) was used to analyse the colour (CIELa*b* scale). Surface roughness (Ra, mm) was measuredusing theprofilometer Surfcorder SE 1700 (Kosaka Corp, Tokyo, Japan). The specimens were subjected to three daily soaks (6 ml, 15 minutes) for 14 days at 37°C. They were washed in distilled water and placed in fresh saliva (30 minutes in the interval). After the third soak in a day, they were stored in fresh saliva overnight. Outcomes were analysed at baseline (L*, a*, b*, Ra) and after degradation (L'*, a'*, b'*, Ra'). RESULTS: The pH values of saliva, sorbet, and juice were 7.0, 3.8, and 4.9, respectively. ΔE* values were 6.6 for saliva, 6.9 for sorbet and 7.8 for juice. There was a significant ΔE* difference between saliva (p=0.005) and juice (p=0.002), and between juice and sorbet (p=0.019), but none between saliva and sorbet (p=0.401). There was no significant Δb* difference between the solutions. No difference between juice and sorbet was observed for Δa*, but they were significantly different from saliva (p<0.001). Brightness (L*) changed significantly. Juice showed the highest ΔE* (7.8) and ΔL* (7.7). No significant change was observed for roughness and there was no difference between the solutions for ARa. CONCLUSIONS: Açaí and saliva led to unacceptable staining, but no significant roughness changes in the resin-modified glass-ionomer cement.


As antocianinas presentes no açaí podem manchar o cimento de ionomero de vidro modificado por resina (CIVMR) devido a baixa resistencia ao manchamento do material. OBJETIVO: O objetivo desse estudo foi avaliar se o açaí compromete a cor e a rugosidade de superficie de um CIVMR in vitro. MATERIAIS E MÉTODOS: Amostras (2 mm de espessura, 8 mm de diámetro) de Vitremer™ (3M ESPE, St Paul, MN, USA) foram preparadas de acordo com as instrugoes do fabricante. O materialfoi espatulado, inserido em um molde de silicone colocado entre duas tiras de poliestireno e fotopolimerizado. Após, as amostras foram randomizadas e alocadas em tres grupos (n=25) de acordo com as solugoes usadas para a degradagao química: saliva artificial (controle) e sorbet de açaí e suco de açaí. Utilizou-se o espectrofotometro CM-2600d/2500d (Konica Minolta, Tokyo, Japan) para a análise da cor (escala CIELa*b*) e o rugosímetro Surfcorder SE 1700 (Kosaka Corp, Tokyo, Japan) para a rugosidade de superficie (Ra, mm). As amostras foram submetidas a tres imersoes diárias (6 ml, 15 minutos) em cada solugao por 14 dias a 37°C, tendo sido lavadas em água destilada e mantidas em saliva fresca (30 minutos) nos intervalos. Após a terceira imersao no dia, as amostras foram mantidas em saliva renovada até o dia seguinte. As variáveis foram analisadas antes (L*, a*, b*, Ra) e depois da degradagao química (L'*, a'*, b'*, Ra'). RESULTADOS: Os valores de pH da saliva, sorbet e suco foram, respectivamente 7,0, 3,8 e 4,9. Houve diferenga significante para ΔE* entre saliva (p=0.005) e suco (p=0.002) e entre suco e sorbet (p=0.019), mas nao entre saliva e sorbet (p=0.401). Nao foi observada diferenga significante para Δb* entre as solugoes. Nao houve diferenga significante para Δa* entre suco e sorbet, mas eles foram significativamente diferentes da saliva (p<0.001). A luminosidade (L*) mostrou alteragao significante. O suco mostrou os maiores valores de ΔE* (7,8) e ΔL* (7,7)". Nao houve mudanga significante para a rugosidade e nao foi observada diferenga significante entre as solugoes para ARa (p>0.05). CONCLUSÃO: O açaí e a saliva causaram manchamento inaceitável do glaze do CIVMR e insignificante alteragao da rugosidade.


Subject(s)
Glass Ionomer Cements , Glass Ionomer Cements/chemistry , Color , Materials Testing , Surface Properties , Carbonated Beverages
3.
Chemistry ; 30(11): e202400244, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38299452

ABSTRACT

Invited for the cover of this issue are the groups of Holger Braunschweig at the Julius-Maximilians-Universität Würzburg, Germany and Eufrânio N. da Silva Júnior at the Universidade Federal de Minas Gerais, UFMG, Brazil. The image depicts the electrochemical synthesis of selenium-containing BODIPY molecules with lightning symbolizing the electrifying synthetic process, while the surrounding elemental chaos hints at the red-shifted absorption and emission and the transformative photophysical properties of these new compounds. Read the full text of the article at 10.1002/chem.202303883.

4.
Anim Nutr ; 16: 395-408, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38371472

ABSTRACT

The present study was to evaluate the effect of trace minerals (Zn, Mn, and Cu) from complexed amino acid minerals (ZMCAA) and bis-glycinate chelated minerals (ZMCGly) in laying hen diets on performance, internal and external egg quality, yolk mineral deposition, intestinal morphometry, and bone characteristics. From 78 to 98 weeks of age, 400 White LSL-Lite strain laying hens were distributed in a randomized design with 4 treatments with 10 replicates per treatment. Treatments were distributed in a 2 × 2 factorial arrangement using either Zn, Mn, and Cu of ZMCAA or ZMCGly source at 2 levels: low (20, 20, and 3.5 mg/kg of Zn, Mn, and Cu, respectively) or high (40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively). The analysis of variance was performed, and in cases where differences were observed, the means were compared using Tukey's test (P < 0.05). The source and level of trace mineral supplementation had a significant impact on the performance of laying hens. Hens fed ZMCAA had higher egg production (P = 0.01), egg weight (P = 0.02), egg mass (P = 0.01), and lower feed conversion ratio (P = 0.05) compared to those fed ZMCGly. The ZMCAA supplementation showed higher albumen height (P = 0.01), albumen weight (P = 0.01), and eggshell thickness (P < 0.01). The deposition of Zn (P < 0.01), Mn (P < 0.01), and Cu (P < 0.01) in the egg yolk was greater for hens received ZMCAA. Tibia weight (P = 0.04) and bone densitometry (P < 0.01) in the tibia were higher with ZMCAA supplementation. In the small intestine, ZMCAA resulted in longer villi (P = 0.02) and shorter crypt depth (P = 0.01) in the duodenum. Jejunum and ileum measurements were influenced by the level and source of trace minerals (P < 0.05). Laying hens fed ZMCAA exhibited superior performance, egg quality, deposition of trace minerals in the egg yolk, and bone density compared to hens fed ZMCGly. In this study, older laying hens supplemented with ZMCAA at lower levels demonstrated adequate levels of supplementation.

5.
Org Lett ; 26(5): 1034-1039, 2024 Feb 09.
Article in English | MEDLINE | ID: mdl-38286095

ABSTRACT

The untapped potential of α-carbonyl sulfoxonium ylides in epoxide ring-opening reactions has been a notable gap in current research, with such reactivity predominantly associated with the highly reactive dimethylsulfoxonium methylide. This study introduces an innovative approach wherein an epoxide indole, formed in situ from 2-hydroxyindoline-3-triethylammonium bromide, undergoes reaction with α-ester sulfoxonium ylides. The outcome is the efficient synthesis of a range of 2-hydroxyindolin-3-ylidenes, demonstrating favorable yields (41-81%) and Z/E ratios from 4:1 to those of exclusive Z isomers. Additionally, the photophysical properties of the synthesized indolinylidenes are explored, along with their derivatization using various nucleophiles under acid catalysis.

6.
Chemistry ; 30(11): e202303883, 2024 Feb 21.
Article in English | MEDLINE | ID: mdl-38085637

ABSTRACT

We report a rapid, efficient, and scope-extensive approach for the late-stage electrochemical diselenation of BODIPYs. Photophysical analyses reveal red-shifted absorption - corroborated by TD-DFT and DLPNO-STEOM-CCSD computations - and color-tunable emission with large Stokes shifts in the selenium-containing derivatives compared to their precursors. In addition, due to the presence of the heavy Se atoms, competitive ISC generates triplet states which sensitize 1 O2 and display phosphorescence in PMMA films at RT and in a frozen glass matrix at 77 K. Importantly, the selenium-containing BODIPYs demonstrate the ability to selectively stain lipid droplets, exhibiting distinct fluorescence in both green and red channels. This work highlights the potential of electrochemistry as an efficient method for synthesizing unique emission-tunable fluorophores with broad-ranging applications in bioimaging and related fields.


Subject(s)
Selenium , Molecular Structure , Boron Compounds , Fluorescence , Fluorescent Dyes
7.
Animals (Basel) ; 13(23)2023 Nov 29.
Article in English | MEDLINE | ID: mdl-38067060

ABSTRACT

A study was conducted to evaluate the effects of different sources and levels of supplemental amino acid-complexed minerals (AACM), with and without enzyme phytase (EZ). A total of 512 Dekalb White laying hens at 67 weeks of age were used in a 2 × 3 + 2 factorial arrangement of 8 treatments and 8 replications each. The main effects included EZ supplementation (10,000 FTU kg-1) and AACM inclusion level (100, 70, and 40% of inorganic mineral recommendations), plus 2 control treatments. The group of hens fed AACM-100 showed lower feed intake than the inorganic mineral (IM) group. The diet containing AACM-EZ-70 provided a higher (p < 0.05) laying percentage and a lower (p < 0.05) feed conversion ratio than both the IM and IM-EZ diets. The groups fed AACM-EZ-40, AACM-EZ-100, and AACM-70 produced heavier yolks (p < 0.05). Hens fed IM laid eggs with the lowest yolk and albumen weights (p < 0.05). Layers fed with AACM-100 and AACM-70 produced the most resistant eggshells to breakage (p < 0.05). In diets containing phytase, the optimal AACM recommendations for better performance and egg quality in older laying hens are: 42, 49, 5.6, 28, 0.175, and 0.70 mg kg-1 for Zn, Mn, Cu, Fe, Se, and I, respectively.

8.
ACS Appl Bio Mater ; 6(7): 2651-2666, 2023 07 17.
Article in English | MEDLINE | ID: mdl-37352500

ABSTRACT

In this work, imidazole- or imidazolium-based benzothiadiazole ligands functionalized on graphene oxide combined with cholesterol oxidase constitute efficient, robust, and easy-to-handle materials with high biosensing activity for the detection of cholesterol by colorimetric methods. The presence of lanthanum(III) supported on graphene oxide as a possible coordinating site for the benzothiadiazole ligands was also evaluated, and its bioactivity was compared to that of the analogous material without the rare-earth metal. Our results demonstrated that graphene oxide functionalized with 4,7-bis-(imidazol-1-yl)-2,1,3-benzothiadiazole exhibited the best performance for the quantification of total cholesterol with a sensitivity of 0.0649 (with lanthanum) and 0.0618 au dL mg-1 (without lanthanum). In addition, these materials presented a better percentage of immobilization (>90%), recovered activity, resistance to storage, and detection range than materials containing 4,7-[1-carboxymethyl-(imidazol-3-ium)]-2,1,3-benzothiadiazole chloride. Therefore, the combination of GO-BTD (Im/Ac)/ChOx (with or without lanthanum) affords efficient biosensors for the colorimetric detection of cholesterol.


Subject(s)
Biosensing Techniques , Lanthanum , Ligands , Biosensing Techniques/methods , Cholesterol
9.
Adv Sci (Weinh) ; 10(20): e2206954, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37132565

ABSTRACT

The interfacial energetics are known to play a crucial role in organic diodes, transistors, and sensors. Designing the metal-organic interface has been a tool to optimize the performance of organic (opto)electronic devices, but this is not reported for organic thermoelectrics. In this work, it is demonstrated that the electrical power of organic thermoelectric generators (OTEGs) is also strongly dependent on the metal-organic interfacial energetics. Without changing the thermoelectric figure of merit (ZT) of polythiophene-based conducting polymers, the generated power of an OTEG can vary by three orders of magnitude simply by tuning the work function of the metal contact to reach above 1000 µW cm-2 . The effective Seebeck coefficient (Seff ) of a metal/polymer/metal single leg OTEG includes an interfacial contribution (Vinter /ΔT) in addition to the intrinsic bulk Seebeck coefficient of the polythiophenes, such that Seff  = S + Vinter /ΔT varies from 22.7 µV K-1 [9.4 µV K-1 ] with Al to 50.5 µV K-1 [26.3 µV K-1 ] with Pt for poly(3,4-ethylenedioxythiophene):p-toluenesulfonate [poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)]. Spectroscopic techniques are used to reveal a redox interfacial reaction affecting locally the doping level of the polymer at the vicinity of the metal-organic interface and conclude that the energetics at the metal-polymer interface provides a new strategy to enhance the performance of OTEGs.

10.
Braz. J. Anesth. (Impr.) ; 73(2): 153-158, March-Apr. 2023. tab, graf
Article in English | LILACS | ID: biblio-1439590

ABSTRACT

Abstract Purpose Several bedside clinical tests have been proposed to predict difficult tracheal intubation. Unfortunately, when used alone, these tests show less than ideal prediction performance. Some multivariate tests have been proposed considering that the combination of some criteria could lead to better prediction performance. The goal of our research was to compare three previously described multivariate models in a group of adult patients undergoing general anesthesia. Methods This study included 220 patients scheduled for elective surgery under general anesthesia. A standardized airway evaluation which included modified Mallampati class (MM), thyromental distance (TMD), mouth opening distance (MOD), head and neck movement (HNM), and jaw protrusion capacity was performed before anesthesia. Multivariate models described by El-Ganzouri et al., Naguib et al., and Langeron et al. were calculated using the airway data. After anesthesia induction, an anesthesiologist performed the laryngoscopic classification and tracheal intubation. The sensitivity, specificity, and receiver operating characteristic (ROC) curves of the models were calculated. Results The overall incidence of difficult laryngoscopic view (DLV) was 12.7%. The area under curve (AUC) for the Langeron, Naguib, and El-Ganzouri models were 0.834, 0.805, and 0.752, respectively, (Langeron > El-Ganzouri, p= 0.004; Langeron = Naguib, p= 0.278; Naguib = El-Ganzouri, p= 0.101). The sensitivities were 85.7%, 67.9%, and 35.7% for the Langeron, Naguib, and El-Ganzouri models, respectively. Conclusion The Langeron model had higher overall prediction performance than that of the El-Ganzouri model. Additionally, the Langeron score had higher sensitivity than the Naguib and El-Ganzouri scores, and therefore yielded a lower incidence of false negatives.


Subject(s)
Laryngoscopes , Neck , ROC Curve , Intubation, Intratracheal , Laryngoscopy
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 294: 122526, 2023 Jun 05.
Article in English | MEDLINE | ID: mdl-36868019

ABSTRACT

A series of amino acid-derived 1,2,3-triazoles presenting the amino acid residue and the benzazole fluorophore connected by a triazole-4-carboxylate spacer was studied for enantioselective recognition using only steady-state fluorescence spectroscopy in solution. In this investigation, the optical sensing was performed with D-(-) and L-(+)-Arabinose and (R)-(-) and (S)-(+)-Mandelic acid as chiral analytes. The optical sensors showed specific interactions with each pair of enantiomers, allowing photophysical responses, which were used for their enantioselective recognition. DFT calculations confirm the specific interaction between the fluorophores and the analytes corroborating the observed high enantioselectivity of these compounds with the studied enantiomers. Finally, this study investigated nontrivial sensors for chiral molecules by a mechanism different than turn-on fluorescence and has the potential to broad chiral compounds with fluorophoric units as optical sensors for enantioselective sensing.

12.
PeerJ ; 11: e14992, 2023.
Article in English | MEDLINE | ID: mdl-36935931

ABSTRACT

Background: Estuaries are transitional coastal ecosystems that are threatened by multiple sources of human pollution. In 2015, mining tailings from an upstream dam failure caused massive metal contamination that impacted benthic assemblages on the Brazilian Rio Doce estuary. Methods: In this study, we investigate and compare meiofaunal assemblages with eDNA metabarcoding 1.7 years (2017) and 2.8 years (2018) after the initial contamination by mine tailings in order to evaluate the continued impact of sediment mine tailing contaminants on the structure of benthic assemblages after the disaster. Results: The community was dominated by Arthropoda and Nematoda 1.7 yr after the impacts (42 and 29% of meiofaunal sequence reads, respectively) but after 2.8 years Arthropoda (64.8% of meiofaunal sequence reads) and Rotifera (11.8%) were the most common taxa. This continued impact on meiofaunal assemblage revealed a lower phylogenetic diversity (7.8-fold) in 2018, despite overall decrease in metal concentration (Al, Ba, Cr, As, Fe, Zn, Mn, Pb, Cd, Co) in sediments. Our data suggests that differences in benthic assemblages and loss of diversity may be influenced by contaminants in sediments of this estuary, and indicate that broad eDNA assessments are greatly useful to understand the full range of biodiversity changes in dynamic estuarine ecosystems.


Subject(s)
Disasters , Ecosystem , Animals , Humans , Phylogeny , Geologic Sediments/chemistry , Environmental Monitoring , Metals , Mining
13.
Braz J Anesthesiol ; 73(2): 153-158, 2023.
Article in English | MEDLINE | ID: mdl-34411628

ABSTRACT

PURPOSE: Several bedside clinical tests have been proposed to predict difficult tracheal intubation. Unfortunately, when used alone, these tests show less than ideal prediction performance. Some multivariate tests have been proposed considering that the combination of some criteria could lead to better prediction performance. The goal of our research was to compare three previously described multivariate models in a group of adult patients undergoing general anesthesia. METHODS: This study included 220 patients scheduled for elective surgery under general anesthesia. A standardized airway evaluation which included modified Mallampati class (MM), thyromental distance (TMD), mouth opening distance (MOD), head and neck movement (HNM), and jaw protrusion capacity was performed before anesthesia. Multivariate models described by El-Ganzouri et al., Naguib et al., and Langeron et al. were calculated using the airway data. After anesthesia induction, an anesthesiologist performed the laryngoscopic classification and tracheal intubation. The sensitivity, specificity, and receiver operating characteristic (ROC) curves of the models were calculated. RESULTS: The overall incidence of difficult laryngoscopic view (DLV) was 12.7%. The area under curve (AUC) for the Langeron, Naguib, and El-Ganzouri models were 0.834, 0.805, and 0.752, respectively, (Langeron...>...El-Ganzouri, p...=...0.004; Langeron...=...Naguib, p...=...0.278; Naguib...=...El-Ganzouri, p...=...0.101). The sensitivities were 85.7%, 67.9%, and 35.7% for the Langeron, Naguib, and El-Ganzouri models, respectively. CONCLUSION: The Langeron model had higher overall prediction performance than that of the El-Ganzouri model. Additionally, the Langeron score had higher sensitivity than the Naguib and El-Ganzouri scores, and therefore yielded a lower incidence of false negatives.


Subject(s)
Laryngoscopes , Neck , Humans , Adult , ROC Curve , Intubation, Intratracheal , Laryngoscopy
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 288: 122050, 2023 Mar 05.
Article in English | MEDLINE | ID: mdl-36495682

ABSTRACT

This study describes the synthesis of new pyromellitic diimide (PMDI) derivatives obtained in good yields from the reaction between pyromellitic dianhydride and aminobenzazoles reactive to proton-transfer in the excited state (ESIPT). In this investigation, a non-ESIPT PMDI was also prepared for comparison. These compounds presented absorption maxima in the ultraviolet region attributed to the allowed 1π-π* electronic transitions. Redshifted absorptions were observed for the ESIPT compounds (3b-3c) due to their π-extended conjugation if compared to the non-ESIPT dye (3a). The compounds presented fluorescence emissions between 300 and 600 nm, dependent on the solvent polarity and their chemical structures. While compound 3a presents a single emission, a dual fluorescence could be observed for compounds 3b-3c. As expected for ESIPT compounds, the emission at higher energies could be related to the excited enol conformer (E*), and the emission with a large Stokes shift was attributed to the keto tautomer (K*). All compounds presented fluorescence emission in the solid state, whereas the ESIPT derivatives presented redshifted emissions with a large Stokes shift, as expected. Cyclic voltammetry was employed to investigate the electrochemical properties of these compounds. The HOMO and LUMO energy levels were estimated at -5.40 to -5.00 eV and -2.84 to -2.62 eV, and good thermal stability (Td > 150 °C) was observed. Quantum chemical calculationsusingTD-DFT and DFT were performed to investigate the electronic and photophysical features of the molecules.

15.
ACS Sens ; 7(10): 2865-2919, 2022 10 28.
Article in English | MEDLINE | ID: mdl-36250642

ABSTRACT

Fluorescent and colorimetric sensors are important tools for investigating the chemical compositions of different matrices, including foods, environmental samples, and water. The high sensitivity, low interference, and low detection limits of these sensors have inspired scientists to investigate this class of sensing molecules for ion and molecule detection. Several examples of fluorescent and colorimetric sensors have been described in the literature; this Review focuses particularly on phenanthro[9,10-d]imidazoles. Different strategies have been developed for obtaining phenanthro[9,10-d]imidazoles, which enable modification of their optical properties upon interaction with specific analytes. These sensing responses usually involve changes in the fluorescence intensity and/or color arising from processes like photoinduced electron transfer, intramolecular charge transfer, intramolecular proton transfer in the excited state, and Förster resonance energy transfer. In this Review, we categorized these sensors into two different groups: those bearing formyl groups and their derivatives and those based on other molecular groups. The different optical responses of phenanthro[9,10-d]imidazole-based sensors upon interaction with specific analytes are discussed.


Subject(s)
Imidazoles , Protons , Imidazoles/chemistry , Colorimetry , Water/chemistry
16.
Res Q Exerc Sport ; 93(1): 120-129, 2022 03.
Article in English | MEDLINE | ID: mdl-32930640

ABSTRACT

Objective: This study aimed to investigate the repeated effect of social media on smartphones immediately before training sessions on inhibitory control (Stroop task), endurance (tethered swimming), countermovement jump (CMJ), and swimming performance (50, 100, and 400-m freestyle) in high-level female swimmers. Methods: It is a randomized and experimental investigation with parallel groups. Twenty-two participants underwent the eight weeks of the experiment. The swimmers (eight to twelve sessions per week with 15.9 ± 1.6 hours/week, and training experience of ~ 5.6 years) were randomized in two groups: control (CON, n = 11) and smartphone (SMA, n = 11). Immediately before each training session, the CON group watched videos about Olympic Games for 30-min. The SMA group used social network smartphone apps during 30-min. The inhibitory control, endurance, CMJ, and swimming performance were measured before and after the eight weeks of intervention. Results: No group x time interaction for 50-m freestyle (F(4, 18) = 1.04; p = .33; η2 = 0.09) and CMJ performance (F(4, 18) = 0.31; p = .58; η2 = 0.03) was found. Both experimental groups improved CMJ (F(2, 20) = 8.71; p = .01; η2 = 0.46). Only the CON group improved the 100-m (p = .02), 400-m freestyle (p = .01), and endurance performance (p = .01). The CON group improved the inhibitory control response (p = .01). Conclusion: It is concluded that the repeated effect of social media on smartphones immediately before swimming training sessions might reduce or nullify training gains on swimming and endurance performance.


Subject(s)
Athletic Performance , Mobile Applications , Social Media , Athletic Performance/physiology , Female , Humans , Smartphone , Swimming/physiology
17.
ACS Appl Mater Interfaces ; 13(49): 59252-59262, 2021 Dec 15.
Article in English | MEDLINE | ID: mdl-34851611

ABSTRACT

The excellent performance of hybrid metal-halide perovskite nanocrystals (NCs) contrasts with their unsatisfactory stability in a high-humidity environment or water. Herein, polymer composite lead-halide perovskites (LHPs) NCs were prepared by casting or spin-coating to produce a high fluorescence yield and a fully water-resistant material. Poly(l-lactide) (PLla), polypropylene glycol (PPGly), and polysulfone (PSU) commercial polymers were used to prepare suspensions of MAPbBr3-HDA NCs (MA: CH3NH3; HDA: hexadecylamine). The MAPbBr3-HDA@PLla suspension exhibited a maximum fluorescence quantum yield of 93% compared to 43% for the pristine MAPbBr3-HDA NCs. Strong emissions around 528 nm were also observed, with the same full width at half maximum value of 20 nm, demonstrating the successful fabrication of brightly luminescent LHP NCs@polymer combinations. Time-resolved photoluminescence measurements directly observed the enhanced spontaneous emission of the NCs induced by the polymeric environment. However, the cast films of MAPbBr3-HDA NCs mixed with PLla or PPGly did not resist water immersion. On the contrary, MAPbBr3-HDA@PPGly/PSU films containing well-dispersed ∼10 nm LHP NCs retained a bright green fluorescence emission even after 18 months under air conditions or water immersion up to 45 °C. From water contact angle measurements, profilometry, and X-ray photoelectron spectroscopy data, it could be assumed that the slightly hydrophobic PSU polymer is responsible for the high water stability of the fluorescent films, which avoids MAPbBr3-HDA NC degradation. This work shows that the LHP NC dispersion in dissolved commodity polymers holds great promise toward the long-term stability of LHP NC composites for the future development of wearable electronic devices and other waterproof applications.

18.
Appl Neuropsychol Adult ; : 1-8, 2021 Nov 08.
Article in English | MEDLINE | ID: mdl-34747667

ABSTRACT

BACKGROUND: The effect of MF induced by exposure time to social media smartphone apps on inhibitory control, heart rate variability (HRV), and high-intensity physical effort following a resistance exercise session might indicate whether strength and conditioning professionals should suggest avoiding smartphone usage before a resistance exercise session. AIM: The objective of this study was to analyze the effect of mental fatigue on inhibitory control, HRV, and countermovement jump (CMJ) in trained adults after resistance exercise. METHODS: A total of 16 trained males (21.4 ± 3.3 years) volunteered in this study. The participants performed resistance exercises with and without mental fatigue. The Stroop Task, countermovement jump, and heart rate variability were evaluated before and after the resistance exercise. The participants used smartphones in the mental fatigue condition, whereas the participants watched TV in the control condition. RESULTS: No condition × time interaction was found for the Stroop accuracy (p = 0.87), CMJ (p = 0.68), SDNN (p = 0.15), or pNN50 (p = 0.15) in the heart rate variability. An interaction was found for Stroop response time (p = 0.01) with a higher response time for the mental fatigue condition (p = 0.01). CONCLUSIONS: Mental fatigue impaired the inhibitory control performance after a resistance exercise session in trained adults.

19.
Percept Mot Skills ; 128(6): 2745-2766, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34404292

ABSTRACT

We studied the effects of repeated inducements of mental fatigue (MF) from using social media on smartphones immediately before training sessions by young male volleyball athletes, focusing specifically on their decision-making, endurance, and countermovement jump performance (CMJ). We pair-matched 24 participants according to their decision-making abilities and then, randomly assigned them to one of two 4-week block training groups: control (CON) and smartphone use (SMA). For a 30-minute period before each training session, the CON group watched TV and the SMA group used social media apps on smartphones. We found a significant group x time interaction effect for decision making (attack, p = 0.03; passing, p = 0.02) during training blocks. More specifically, only the CON group improved their decision making (attack, p = 0.03; passing, p = 0.02). Both groups significantly improved their CMJ performance (p = .01), with no significant group x time interaction effect for CMJ (p = 0.91). Neither group significantly improved their endurance (p = 0.56). We concluded that 30-minutes of repetitive social media app use on a smartphone immediately before 4-weeks of volleyball training sessions negatively affected decision-making in young male volleyball athletes.


Subject(s)
Athletic Performance , Social Media , Volleyball , Humans , Male , Mental Fatigue , Muscle Fatigue , Muscle Strength
20.
Chem Rec ; 21(10): 2702-2738, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34170622

ABSTRACT

Diverse structural frameworks are found in natural compounds and are well known for their chemical and biological properties; such compounds include the imidazoles and oxazoles. Researchers worldwide are continually working on the development of methods for synthesizing new molecules bearing these basic moiety and evaluating their properties and applications. To expand the knowledge related to azoles, this review summarizes important examples of imidazole and oxazole derivatives from 1,2-dicarbonyl compounds, such as lapachones and phenanthrene-9,10-diones, not only regarding their synthesis and biological applications but also their photophysical properties and uses. The data concerning the latter are particularly scarce in the literature, which leads to underestimation of the potential applications that can be envisaged for these compounds.


Subject(s)
Oxazoles , Phenanthrenes , Imidazoles
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