Activity

Room-temperature phosphorescence (RTP) materials are desirable in chemical sensing because of their long emission lifetime and they are free from background autofluorescence. selleck chemical Nevertheless, the achievement of RTP in aqueous solution is still a highly challenging task. Herein, a molten salt method to prepare carbon dot (CD)-based RTP materials is presented by direct calcination of carbon sources in the presence of inorganic salts. The resultant CD composites (CDs@MP) exhibit bright RTP with a quantum yield of 26.4% and a lifetime of 1.28 s, which lasts for about 6 s to the naked eye. Importantly, their aqueous dispersion also has good RTP characteristics. This is the first time that the long-lived CDs@MP with RTP are achieved in aqueous solution owing to the synergistic effect of crystalline confinement and aggregation-induced phosphorescence. Further investigations reveal that three key processes may be responsible for the observed RTP of the composite materials (1) The rigid crystalline salt shell can preserve the triplet states of CDs@MP in water and suppress the nonradiative deactivation; (2) The addition of high-charge-density metal ions Mg(II) and phosphorus element in the composite facilitates the singlet-to-triplet intersystem crossing process and enhances the RTP emission; (3) The aggregation of CDs@MP nanocomposites enables the matrix shell to self-assemble into a network, which further improves the rigidity of the shell and prevents the intermolecular motions, hence prolonging the RTP lifetime. The unique RTP feature and good water dispersibility allow the CD-based composite materials to be applicable in detection of temperature and pH in the aqueous phase. Our approach for producing long-lived RTP CDs@MP is effective, simple, and low-cost, which opens a new route to develop RTP materials that are applicable in aqueous solution.Developing cancer targeted medicine depends on increasing delivery efficiency and tumor site accumulation of theranostic agents. To accomplish this, we report a modification of PTK7 receptor-specific aptamer Sgc8 with the small molecule Evans Blue (EB), thus implementing an albumin binding hitchhike strategy for prolonged blood circulation. The EB molecule could insert into the hydrophobic region of serum albumin and form an aptamer/albumin complex. This complex showed superior physiological stability, facilitating longer blood half-life, and maintaining its targeting capacity. Successful conjugation of EB-aptamers was confirmed by a series of characterization methods. Targeting performance was tested on a xenografted mouse tumor model. Taking advantage of the long circulating aptamer/HSA complex, improved accumulation, and delivery efficiency to the tumor site were achieved. Through ex vivo quantification of the EB-Sgc8 aptamers’ biodistribution, the mechanism of improved targeting performance was illuminated. Therefore, the increased aptamers tumor delivery efficiency and accumulation indicate that prolonging blood circulation is a promising strategy to improve aptamers’ targeted delivery performance in the future clinical translation.Enriching and locating target analytes into specific “hot spots” are vital for ultrasensitive molecular identification and detection using plasmonic-based techniques. Inspired by mass transportation in lamp wicks, we develop an effective enrichment strategy for highly diluted analytes in which analytes and Au nanoparticles are transported via a solution microflow under the capillarity driving force of glass fiber papers to a heated region. After evaporation, a large volume of a solution containing analytes and Au nanoparticles is condensed into a very limited area, and thus, analyte molecules are effectively enriched and located into surface-enhanced Raman scattering (SERS) hot spots. Using this enrichment strategy, the sensitivity and detection limits of SERS are remarkably improved. Detection levels of crystal violet and anthracene are down to 10-16 and 10-10 M, respectively. This enrichment strategy is very robust and easy to implement, and it can potentially be exploited in various plasmonic-based molecular detection and identification techniques.Gallium-based room-temperature liquid metals have enormous potential for realizing various applications in electronic devices, heat flow management, and soft actuators. Filling narrow spaces with a liquid metal is of great importance in rapid prototyping and circuit printing. However, it is relatively difficult to stretch or spread liquid metals into desired patterns because of their large surface tension. Here, we propose a method to fabricate a particle-based porous material which can enable the rapid and spontaneous diffusion of liquid metals within the material under a capillary force. Remarkably, such a method can allow liquid metal to diffuse along complex structures and even overcome the effect of gravity despite their large densities. We further demonstrate that the developed method can be utilized for prototyping complex three-dimensional (3D) structures via direct casting and connecting individual parts or by 3D printing. As such, we believe that the presented technique holds great promise for the development of additive manufacturing, rapid prototyping, and soft electronics using liquid metals.Two-dimensional (2D) van der Waals (vdW) heterostructures herald new opportunities for conducting fundamental studies of new physical/chemical phenomena and developing diverse nanodevice applications. In particular, vdW heterojunction p-n diodes exhibit great potential as high-performance photodetectors, which play a key role in many optoelectronic applications. Here, we report on 2D MoTe2/MoS2 multilayer semivertical vdW heterojunction p-n diodes and their optoelectronic application in self-powered visible-invisible multiband detection and imaging. Our MoTe2/MoS2 p-n diode exhibits an excellent electrical performance with an ideality factor of less than 1.5 and a high rectification (ON/OFF) ratio of more than 104. In addition, the photodiode exhibits broad spectral photodetection capability over the range from violet (405 nm) to near-infrared (1310 nm) wavelengths and a remarkable linear dynamic range of 130 dB within an optical power density range of 10-5 to 1 W/cm2 in the photovoltaic mode. Together with these favorable static photoresponses and electrical behaviors, very fast photo- and electrical switching behaviors are clearly observed with negligible changes at modulation frequencies greater than 100 kHz. In particular, inspired by the photoswitching results for periodic red (638 nm) and near-infrared (1310 nm) illumination at 100 kHz, we successfully demonstrate a prototype self-powered visible-invisible multiband image sensor based on the MoTe2/MoS2 p-n photodiode as a pixel. Our findings can pave the way for more advanced developments in optoelectronic systems based on 2D vdW heterostructures.BACKGROUND Warm-up is considered essential to optimize running performance, but little is known about the effect of specific warm-up tasks, specifically in the real competitive context. The current study aimed to verify the acute effects of a warm-up including ballistic exercises in 30m running performance. In addition, a second 30m trial was assessed to better understand the warm-up effects in training/competition. METHODS Twenty-two men (19.32±1.43 years-old) randomly completed the time- trials on separate days and after a typical warm-up (WU), a WU complemented with ballistic exercises (post-activation potentiation – PAP) or no warm-up (NWU). Biomechanical, physiological and psychophysiological variables were assessed. RESULTS The participants were 1.9% faster in the first 30m sprint after WU compared with NWU, mainly increased performance in the first 15m (p=0.03, ES=0.48). WU resulted in greater stride length in the last 15m of the first sprint. PAP did not differ from NWU and WU, despite eight participants performed better after this warm-up. CONCLUSIONS These results highlight the positive effects of warm- up for sprinting, despite failed to evidence positive effects when ballistic exercises are included. In addition, the influence of warm-up in the running technique was highlighted by the changes in the running kinematics and a need for individualization of warm-up procedures.BACKGROUND The aim of this study was to examine the effect of the menstrual cycle on running economy (RE). METHODS Using a repeated-measures design, ten eumenorrheic, trained female runners (age 32 ± 6 yrs, V̇ O2max 59.7 ± 4.7 mL·kg-1·min-1) completed four, weekly, identical sub-maximal and maximal incremental step tests on a treadmill to measure physiological responses across a full menstrual cycle. For phase comparison, the results from the trials that fell in the early follicular (low oestrogen, low progesterone), late follicular (high oestrogen, low progesterone) and mid-luteal (high oestrogen, high progesterone) phases were used. RESULTS There was a significant effect of menstrual cycle phase on RE (p = 0.001), with RE in the mid-luteal (ML) phase being worse than that of the early follicular (EF) (+2.33 mL.kg-1.min-1; p = 0.026) and late follicular (LF) (+2.17 mL.kg-1.min-1; p = 0.011) phases. The ML phase also resulted in elevated core temperature versus the EF (+0.51oC; p = 0.001) and LF (+0.66oC; p = 0.037) phases, and elevated minute ventilation versus the EF phase (+3.83 L.min-1; p = 0.003). No significant effects of menstrual cycle phase were found on body mass, heart rate, ratings of perceived exertion, time-to-exhaustion, maximal oxygen consumption, or blood lactate concentration. CONCLUSIONS In the ML phase, which causes increased core temperature and minute ventilation, RE is impaired at exercise intensities that are applicable to training and performance. In physiologically stressful environments, this impairment in RE may have a significant impact on training and performance.BACKGROUND The purpose of this study was to investigate if a post-activation potentiation (PAP) protocol may attenuate the acute interference induced by high- intensity intermittent exercise (HIIE) and on subsequent strength exercise performance in recreationally trained men. METHODS Eleven resistance-trained men (age 25.7±3.7 y) randomly completed three experimental trials Strength Exercise (SE) only (4 sets of maximal number of repetitions at 70% on the 45o leg press); Concurrent Exercise (CE) comprised 5000-m of HIIE at maximal aerobic speed (11 effort and pause ratio) followed by SE protocol; Concurrent Exercise with post-activation potentiation (CE- PAP), comprised the same CE protocol preceded by one set of 2 repetitions at 90% of 1RM on the 45° leg-press before strength exercise. The number of repetitions performed was recorded for each set and total weight lifted was calculated. RESULTS The CE condition induced a greater decrement in volume for the leg press compared to SE and CE-PAP in sets 1 (24±21%; 18±25%), 2 (20±21%; 22±22%), and 3 (19±20%; 25±15%), respectively. Total weight lifted was greater after SE (8,795 ± 2,581 kg) and CE-PAP (8,809 ± 2,655 kg) conditions compared to CE (7,049 ± 2,822 kg) (SE vs CE p = 0.020) and (CE-PAP vs CE p = 0.010) but there was no significant difference between SE and CE-PAP (p= 1.00). CONCLUSIONS PAP using a heavy load attenuated acute interference (total volume during lower-body strength) generated by HIIE protocol, but did not enhance volume compared to strength exercise alone.