Intense Output Research Articles

Red-to-ultraviolet light chargeable Sm2+-activated deep-red persistent phosphor for simultaneous bioimaging and bio-temperature sensing

Persistent phosphor-based bio-applications do not need real-time photo-excitation and do not suffer from disturbance of stray excitation light, auto-fluorescence of the measured substance and heat produced by excitation. However, the persistent phosphors that well match the optical biological windows are deficient. Here, we report for the first-time divalent samarium (Sm2+) activated persistent phosphor with dual-functionality for simultaneous bioimaging and bio-temperature sensing. The persistent phosphor is Sm2+ and Nd3+codoped SrAl2Si2O8 that can be photo-charged in 250–660 nm and shows deep-red persistent luminescence (PersL) originated from both the 4f55d1 → 4f6 and 5D0 → 7FJ (J = 0, 1, 2, 3, 4) transitions that well match the first optical biological window. The intense PersL output shows the effective operation temperature range of 240–340 K, covering the physiological temperature range of 298–325 K. It is found that quantum tunneling dominates both the visible light including red light charging process and PersL generating process. The temperature dependent PersL intensity ratio of the thermally coupled 4f55d1 → 4f6 emission band and the 5D0 → 7FJ emission lines is studied and a maximum relative sensitivity of 4.81 % K−1 at 200 K and 2.17–1.82 % K−1 in the physiological temperature range are achieved. The dual-functionality of SrAl2Si2O8:1 %Sm2+,1 %Nd3+ for simultaneous bioimaging and bio-temperature sensing is demonstrated. Our findings open up new scenarios for multifunctional applications of Sm2+.

Simulations of collisional effects in an inner-shell solid-density Mg X-ray laser.

Inner-shell [Formula: see text] X-ray lasers have been created by pumping gaseous, solid, and liquid targets with the intense X-ray output of free-electron lasers (FELs). For gaseous targets lasing relies on the creation of [Formula: see text]-shell core holes on a time-scale short compared with filling via Auger decay. In the case of solid and liquid density systems, collisional effects will also be important, affecting not only populations but also line-widths, both of which impact the degree of overall gain, and its duration. However, to date, such collisional effects have not been extensively studied. We present here initial simulations using the CCFLY code of inner-shell lasing in solid-density Mg, where we self-consistently treat the effects of the incoming FEL radiation and the atomic kinetics of the Mg system, including radiative, Auger and collisional effects. We find that the combination of collisional population of the lower states of the lasing transitions and broadening of the lines precludes lasing on all but the [Formula: see text] of the initially cold system. Even assuming instantaneous turning on of the FEL pump, we find the duration of the gain in the solid system to be sub-femtosecond. This article is part of the theme issue 'Dynamic and transient processes in warm dense matter'.

Highly luminescent Gd2O2S:Er3+,Yb3+ upconversion microcrystals obtained by a time- and energy-saving microwave-assisted solid-state synthesis

Er3+-doped and Er3+,Yb3+-co-doped Gd2O2S are one of the most efficient upconversion (UC) materials available to date. However, preparing lanthanide oxysulfides can be challenging as it requires several hours of heating at>1000 °C in high power furnaces. Nonetheless, in designing a new synthesis technology for UC materials, one should consider that these systems suffer from defect quenching, responsible for significant optical energy losses. In this work, the microwave-assisted solid-state (MASS) synthesis was explored as an alternative to synthesize this class of materials, using two different starting compounds – lanthanide oxides (Ln2O3) and hydroxycarbonates (Ln(OH)CO3), where Ln3+: Gd, Er, Yb. Different Er3+,Yb3+ concentrations were investigated, and the Er3+(5%),Yb3+(5%) and Er3+(1%),Yb3+(10%) were shown to give the most intense UC output comparable to commercially available materials. Using Ln(OH)CO3 instead of the more common Ln2O3 for the MASS synthesis contributed to higher UC efficiencies and a more homogeneous Er3+ and especially Yb3+ distribution through the Gd2O2S lattice as verified by luminescence lifetime measurements. These high-quality materials were prepared in a simple two-step synthesis of 50 min and using a domestic microwave oven, leading to a remarkable decrease of 79% in processing time and 93% in energy consumption, making the MASS method suitable to be explored as an alternative synthesis methodology for high performance UC materials.

Source-oriented risks apportionment of toxic metals in river sediments of Bangladesh: a national wide application of PMF model and pollution indices.

Intense human activities, particularly industrial and agricultural output, has enriched metal(loid)s in riverine sediment and endangered aquatic ecosystems and human health. Promoting proper river management requires an assessment of the possible ecological hazards and pollution posed by metal(loid)s in sediments. However, there are limited large-scale risk assessments of metal(loid)s contamination in riverine sediment in heavily populated nations like Bangladesh. This study compiled data on sediment metal(loid)s, for example, Cd, As, Cu, Ni, Cr, Pb, Mn, and Zn, from 24 major rivers located across Bangladesh between 2011 and 2022 and applied positive matrix factorization (PMF) to identify the critical metal(loid)s sources and PMF model-based ecological risks. Based on studied metal(loid)s, 12-78% of rivers posed higher contents than the upper continental crust and 8% of the river sediments for Cr and Ni, whereas 4% for Cd and As exceeded probable effect concentration. Cr and Ni in the sum of toxic units (STU), whereas Mn, As and Cd in potential ecological risk (PER) posed the highest contribution to contaminate sediments. In the studied rivers, sediment contaminant Mn derived from natural sources; Zn and Ni originated from mixed sources; Cr and Cu were released from the tannery and industrial emissions and Cd originated from agricultural practices. Source-based PER and NIRI indicated that mixed source (4% rivers) and tannery and industrial emission (4% rivers) posed very high risks in sediments. For the creation of macroscale policies and the restoration of contaminated rivers, our national-scale comprehensive study offers helpful references.

A method of real-time monitoring beam output stability of intense pulsed ion beam

Intense pulsed ion beam (IPIB) technology has made remarkable progress in surface modification, mixing, polishing, film deposition, and nano powder synthesis in recent years. However, the surface properties of materials under IPIB irradiation are highly sensitive to beam intensity variations. Deviations from acceptable parameter range can change the surface characteristics and increase prevalence of defects. Consequently, the real-time online monitoring of beam stability during irradiation experiments and promptly identifying of pulses exhibiting significant parameter jitter are of significance in accurately analyzing results and optimizing surface modification. This study presents a fast-response pulse X-ray diagnostic system by employing EJ-200 plastic scintillator, 9266FLB photomultiplier tube, and Tektronic TDS 2024 four-channel oscilloscope. Single particle test demonstrates that the system achieves a time resolution of 6 ns, meeting the requirements for temporal response to detecting pulse X-ray signals with a half-width of ~80 ns. By adjusting the insulation magnetic field strength of the ion diode, the IPIB output level is regulated. The diagnostic system successfully captures X-rays emitted by the external magnetic insulated ion diode operating at different output levels. Simultaneously, the ion beam energy density is measured by using an infrared camera. To mitigate diagnostic errors stemming from target ablation, the maximum energy density is controlled to be below 1.32 J/cm<sup>2</sup>. Analysis results establish a positive correlation between X-ray intensity and ion beam energy density. This relationship arises from the influence of the insulating magnetic field adjustment on the diode's operating voltage, which subsequently affects the bremsstrahlung radiant intensity and ion beam emission intensity. This correlation offers the potential for the real-time monitoring of IPIB beam output stability by utilizing X-ray signals. To further corroborate the synchronized changes in pulse X-ray intensity and ion beam intensity, Faraday cup is employed as an alternative to infrared imaging method for measuring ion current density. Results demonstrate that the amplitude of the X-ray signal changes synchronously with fluctuations of ion current density. It is worth noting that when the output intensity of ion beam deviates significantly (more than 10% of the preset value), the diagnostic system will respond quickly. These findings validate the efficacy of the proposed non-interceptive diagnostic method of real-time monitoring the intense pulsed ion beam output stability.

Europium metal-organic framework containing helical metal-carboxylate chains for fluorescence sensing of nitrobenzene and nitrofunans antibiotics

Food safety and environmental pollution have become prevalent concerns around the world. The development of a facile detection method towards nitroaromatic pollutants and antibiotics in the environment is exceedingly desirable for protecting human health and controlling the risks of sanitation pollution. Herein, a new europium metal-organic framework (Eu-MOF), which is built from helical rod-shaped europium carboxylate chains, has been synthesized and broadly explored. The compound exhibits intense red luminescence output of typical Eu3+ ions both in solid and in the alcohol solutions. Notably, it shows rapid and efficient fluorescence quenching effects towards the nitrobenzene (NB) and nitrofurans antibiotics (NFAs). As a dual-functional chemosensor, the Eu-MOF has a broad application prospect for its sensitive identification and visual detection in the future. The mechanism of the quenching effect was investigated in detail, and the density functional theory also proved the result.

ANALYSIS OF CAST IRON QUALITY PULSATIONS IN THE BLAST-FURNACE PROCESS

The frequency and velocity of fluctuations of physical and chemical properties of cast iron at three blast furnaces are studied, the furnaces worked with the use of the same raw material conditions with the injection of pulverized coal fuel up to150 kg/ ton of pig iron. Only at one furnace the frequency of occurrence of highs on the curve of changes in the content of sulfur in iron has been found, which indicates the possibility of formation and destruction of the skull in accordance with known dependencies in the mode of self-oscillation. At two other furnaces there was an aperiodicity of sharp changes in the quality of cast iron, depending on external factors. The results of earlier studies and the data of the presented work allow us to state the appropriateness of predicting extreme emissions of sulfur in the cast iron at separate furnaces to provide the rhythmic operation of the pig iron at ladle refining installation.It is usually believed that there is a close direct connection between the temperature of the iron and the silicon content in it - the higher the temperature of the metal, the more it contains silicon. The periods of the furnace operation are considered when the trends in the change of physical and chemical heating of the iron coincide and when they have the opposite direction. In the second case, the increase in temperature of iron is due to the weakening of endothermic direct silica recovery.It is shown that the extreme emission of sulfur in iron, which is considered to be a sign of changing of skull state in the furnace, corresponds to other signs - a sharp transition from the molted to acidic slags, the maximum release of alkaline compounds with slag, in particular K2O, synchronous change in the basicity of slag with changes in alkaline content but in opposite directions. That is, the negative effect of the scull slipping in the blast furnace process is partially offset by the removal of alkalis from the working space of the furnace. In contrast to the widespread view, it was found that both the reduced basicity of slag and its high temperature influence the intense output of alkaline compounds.

Gas sensing through evanescent coupling of spoof surface acoustic waves

An ultrasonic gas sensor based on evanescent coupling of spoof surface acoustic waves between two surface phononic crystals containing trapezoidal grooves on rigid slabs is theoretically and experimentally demonstrated. Sensing properties for carbon dioxide in dry air at 25 °C and 760 Torr are investigated as an example. Band structure analyses reveal two spoof surface acoustic wave bands with opposite parities when the separation of surface phononic crystals is 1.5 times the periodicity of grooves. The beat length varies with frequency and carbon dioxide volume fraction, where the increase of the latter results in red shift of a sharp intense output peak at 59.69 kHz at a rate of 17.70 mHz/ppm and 16.20 mHz/ppm for carbon dioxide volume fractions up to 10,000 ppm, as measured through Finite-Element Method simulations and experiments, respectively. Gas sensing can also be achieved by measuring the output acoustic intensity at constant frequency, which exhibits a steep decrease with carbon dioxide volume fraction up to 2000 ppm.

Physiological changes in post-hatchling green turtles (Chelonia mydas) following short-term fasting: implications for release protocols.

Relocation of sea turtle nests and the retention of post-hatchlings for head-starting programs are both commonly used to improve conservation outcomes and facilitate eco-tourism ventures. Currently, there is little literature surrounding the husbandry protocols required during these programs to optimize post-release outcomes. To assess the impact of varied feeding regimes on exercise performance, (which will hereafter be referred to as 'fitness'), 40 10-month-old captive post-hatchling green turtles (Chelonia mydas) were divided into four groups of 10 and fasted for either 3, 9, 10 or 15h. The animals were then subjected to a fitness test via repetitive use of the 'righting reflex' on land. Health assessments were conducted prior to the fitness test, including; heart rate, haematocrit (Hct), heterophil to lymphocyte ratio and the measurement of 11 biochemical analytes, including pH, partial pressures of carbon dioxide (PvCO2) and oxygen (PvO2), lactate, bicarbonate (HCO3 -), sodium (Na+), potassium (K+), chloride (Cl-), ionized calcium (iCa2+), glucose and urea. Results were corrected for multiple comparisons and significant differences among groups were demonstrated for temperature, pH, HCO3 -, iCa2+, urea and lactate. To investigate physiological relationships between analytes, correlation coefficients were calculated between fitness and glucose, fitness and lactate, glucose and lactate, pH and iCa2+, pH and K+, pH and PvCO2, pH and HCO3 - and Hct and K+. Following correction for multiple comparisons, significant relationships were seen between pH and iCa2+ and pH and HCO3 -. Post-hatchling turtles appear to enter a catabolic state when exposed to short-term fasting. While this did not have a direct impact on fitness, the production of an intense energetic output from a catabolic state may induce a physiological debt. This study suggests that handling that induces a physical response should be minimized and animals should be fed within 10h of release.

Period multiplication in a parametrically driven superconducting resonator

We report on the experimental observation of period multiplication in parametrically driven tunable superconducting resonators. We modulate the magnetic flux through a superconducting quantum interference device, attached to a quarter-wavelength resonator, with frequencies nω close to multiples, n = 2, 3, 4, and 5, of the resonator fundamental mode and observe intense output radiation at ω. The output field manifests n-fold degeneracy with respect to the phase, and the n states are phase shifted by 2π/n with respect to each other. Our demonstration verifies the theoretical prediction by Guo et al. [Phys. Rev. Lett. 111, 205303 (2013)] and paves the way for engineering complex macroscopic quantum cat states with microwave photons.

The G Protein Gamma Subunit, Ste18, is a Phosphorylation‐Dependent pH Sensor that Controls MAPK Activation in Yeast

As essential transducers of extracellular stimuli such as hormones and neurotransmitters, G protein signaling (GPS) systems – comprised of seven transmembrane receptors (GPCRs), heterotrimeric G‐proteins (Gαβγ), and regulators of G‐protein signaling (RGS) proteins – are important regulators of cell/environment homeostasis in all eukaryotes. Yeast harbor a single canonical GPS system that regulates a pheromone‐dependent mating response, which has long served as a tool for discovering regulators fundamental for all eukaryotic GPS systems. In wild type yeast, the activation rate and amplitude of pheromone signaling is severely dampened by negative feedback phosphorylation of the canonical Gγ subunit, Ste18, and the MAPK scaffold, Ste5. Here, we show that Ste18 is a pH sensor that undergoes combinatorial phosphorylation/dephosphorylation in response to fluctuations in intracellular pH (pHi). Using a site‐specific phosphorylation‐dependent electrophoretic mobility assay and a pHi probe (pHlourin), we show that Ste18S3 is rapidly phosphorylated in response to intracellular acidification, while Ste18S7 is rapidly phosphorylated in response to mating pheromone. When pHi is lowered, basal phosphorylation on Ste18S7 decreases concomitantly with increasing phosphorylation on Ste18S3. In contrast, pheromone stimulation activates phosphorylation on Ste18S7, but not Ste18S3. We show that phosphomimic mutations on either phosphosite function to prohibit phosphorylation of the other non‐mutated site, demonstrating that phosphorylation is mutually exclusive. Furthermore, phosphorylation at either site, mimicked by glutamate mutations, is sufficient to inhibit ultra‐fast and intense output from the pheromone pathway. Thus, our findings suggest that Ste18Nt acts as a phosphorylation‐dependent pH‐sensor that is capable of restricting pheromone pathway output under acid stress conditions when yeast mating is sub‐optimal. Considering that dysregulation of pHi is linked to chronic and life‐threatening diseases such as cancer, stroke, and Alzheimer's disease, our data reveal the possibility that Gγ subunits serve as pH sensors important for regulating G protein signaling in such diseases.Support or Funding InformationNational Institutes of Health (NIH)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Radiation Hard Plastic Scintillators for a New Generation of Particle Detectors

The radiation hardness of specific scintillating materials used in particle physics experiments is one of the main focuses of research in detector development. This report summarizes the preparation methods, light yield characterization and radiation damage tests of a plastic scintillator with a polysiloxane base and pTP and bis-MSB dopants. The scintillator is shown to be a promising candidate for particle detectors with its intense light output around 400 nm and very little scintillation or transmission loss after proton irradiation of 4 × 105 Gy.

Development of an in Situ NMR Photoreactor To Study Environmental Photochemistry.

Photochemistry is a key environmental process directly linked to the fate, source, and toxicity of pollutants in the environment. This study explores two approaches for integrating light sources with nuclear magnetic resonance (NMR) spectroscopy: sample irradiation using a "sunlight simulator" outside the magnet versus direct irradiation of the sample inside the magnet. To assess their applicability, the in situ NMR photoreactors were applied to a series of environmental systems: an atmospheric pollutant (p-nitrophenol), crude oil extracts, and groundwater. The study successfully illustrates that environmentally relevant aqueous photochemical processes can be monitored in situ and in real time using NMR spectroscopy. A range of intermediates and degradation products were identified and matched to the literature. Preliminary measurements of half-lives were also obtained from kinetic curves. The sunlight simulator was shown to be the most suitable model to explore environmental photolytic processes in situ. Other light sources with more intense UV output hold potential for evaluating UV as a remediation alternative in areas such as wastewater treatment plants or oil spills. Finally, the ability to analyze the photolytic fate of trace chemicals at natural abundance in groundwater, using a cryogenic probe, demonstrates the viability of NMR spectroscopy as a powerful and complementary technique for environmental applications in general.

Fluorescence Turn-on Chemosensor for the Detection of Dissolved CO2 Based on Ion-Induced Aggregation of Tetraphenylethylene Derivative.

Herein, a sensitive fluorimetric assay for dissolved carbon dioxide (dCO2) was developed by using ion-induced self-assembly of a tetraphenylethylene derivative by taking advantage of its aggregation induced emission property. Chitosan, a commercially available polymer having amine functionality was utilized for the ion induced assay. In the presence of dCO2, the amine groups in the chitosan get protonated to convert neutral chitosan to a positively charged species, triggering negatively charged tetraphenylethene derivative (probe 1) to aggregate with it by electrostatic interaction. The aggregation causes intense blue fluorescence output from the system. The extent of the aggregation is reliant on the charge density of polymer, which is equivalent to dCO2 concentration. A linear relationship from 5 to 50 μM of dCO2, with a limit of detection of 5 × 10(-6) M (0.00127 hPa) was obtained. This is the first report for detecting dCO2 utilizing the AIE property.

Locomotor Adaptability Task Promotes Intense and Task-Appropriate Output From the Paretic Leg During Walking

ObjectiveTo test the hypothesis that participants with stroke will exhibit appropriate increase in muscle activation of the paretic leg when taking a long step with the nonparetic leg compared to during steady-state walking, with a consequent increase in biomechanical output and symmetry during the stance phase of the modified gait cycle. DesignSingle-session observational study. SettingClinical research center in an outpatient hospital setting. ParticipantsAdults with chronic poststroke hemiparesis (N=15). InterventionsParticipants walked on an instrumented treadmill while kinetic, kinematic, and electromyogram data were recorded. Participants performed steady-state walking and a separate trial of the long-step adaptability task in which they were instructed to intermittently take a longer step with the nonparetic leg. Main Outcome MeasuresForward progression, propulsive force, and neuromuscular activation during walking. ResultsParticipants performed the adaptability task successfully and demonstrated greater neuromuscular activation in appropriate paretic leg muscles, particularly increased activity in paretic plantarflexor muscles. Propulsion and forward progression by the paretic leg were also increased. ConclusionsThese findings support the assertion that the nonparetic long-step task may be effective for use in poststroke locomotor rehabilitation to engage the paretic leg and promote recovery of walking.

Oscillation-Starting Conditions for Oversized $G$ -Band (140–220 GHz) Backward Wave Oscillator Driven by Weakly Relativistic Electron Beam

An oversized $G$ -band backward wave oscillator (BWO) driven by a weakly relativistic electron beam less than 100 kV is studied. Rectangular corrugations are used as the slow-wave structure (SWS), which have surface waves with upper cutoff frequencies of above 150 GHz [ $G$ -band (140–220 GHz)]. In this paper, we examine the starting conditions for intense $G$ -band BWO operation by varying the beam parameters and SWS lengths. It is shown that a starting energy exists for the $G$ -band BWO and that the starting energy is more critical than the starting current in the oversized BWO. Above the starting energy, very intense output powers on the order of 10 kW are obtained. The oscillation-starting condition for such intense operation may play an important role in high-intensity terahertz wave sources.

Gradient CdSe/CdS Quantum Dots with Room Temperature Biexciton Unity Quantum Yield.

Auger recombination is a major limitation for the fluorescent emission of quantum dots (QDs). It is the main source of QDs fluorescence blinking at the single-particle level. At high-power excitation, when several charge carriers are formed inside a QD, Auger becomes more efficient and severely decreases the quantum yield (QY) of multiexcitons. This limits the efficiency and the use of colloidal QDs in applications where intense light output is required. Here, we present a new generation of thick-shell CdSe/CdS QDs with dimensions >40 nm and a composition gradient between the core and the shell that exhibits 100% QY for the emission of both the monoexciton and the biexciton in air and at room temperature for all the QDs we have observed. The fluorescence emission of these QDs is perfectly Poissonian at the single-particle level at different excitation levels and temperatures, from 30 to 300 K. In these QDs, the emission of high-order (>2) multiexcitons is quite efficient, and we observe white light emission at the single-QD level when high excitation power is used. These gradient thick shell QDs confirm the suppression of Auger recombination in gradient core/shell structures and help further establish the colloidal QDs with a gradient shell as a very stable source of light even under high excitation.

Luminescent and scintillation properties of orthotantalates with common formulae RETaO4 (RE=Y, Sc, La, Lu and Gd)

Abstract Samples of undoped and Ce-, Eu- and Pr-doped orthotantalates with common formulae RETaO 4 (RE = Y, Sc, La, Lu and Gd) have been obtained by solid-state reaction. Optical and luminescent characteristics in visible and UV bands have been explored. The most intense light output is determined for GdTaO 4 , YTaO 4 , and LuTaO 4 (for GdTaO 4 it is 111% compared to BGO). Among lanthanide-doped samples, the highest light output is achieved with Eu-doped YTaO 4 , GdTaO 4 and LuTaO 4 (up to 136% compared to BGO). Undoped rare-earth tantalates may be considered as promising materials for high energy physics due to extremely high density, substantial light output, and fast decay. Eu 3+ -doped orthotantalates are the brightest among the studied samples for X-ray radiography, or other application where slow decay is acceptable.

A stigmatic ultraviolet-visible monochromator for use with a high brightness laser driven plasma light source

Laser driven plasma light sources offer highly intense output in the UV-visible region combined with a source size as small as 100 μm. In order to effectively use the small source size in high brightness applications, a stigmatic monochromator and focusing system must be used. Here we describe a simple brightness preserving optical system that should be useful across a broad range of applications. The output flux of this system is between 6 × 10(11) ph∕s and 4 × 10(12) ph∕s with a spectra resolution of 1.7 nm and field spot size of 0.1 mm from the UV to the VIS spectra range.

Photodetection and piezoelectric response from hard and flexible sponge-like ZnO-based structures

In this work a comprehensive characterization of sponge-like nanostructured zinc oxide films is proposed, with a marked attention to the exhibited sensing properties. Sponge-like zinc oxide films were grown on different kinds of hard and flexible substrates, by a two-step process involving a room temperature sputtering deposition of metallic sponge-like zinc films, followed by a low-temperature oxidation treatment. This method allowed growing films with thickness of a few micrometers. The material presented a polycrystalline porous structure with randomly oriented grains. After the formation of top electrodes, the sensing properties of the samples were assessed. In particular, the films exhibited UV sensing capability, with photocurrents up to four orders of magnitude higher than the current values measured in dark conditions. The material also showed considerable piezoelectric response: the mechanical stimulus exerted by the impact of a water drop delivered on its surface generated intense piezoelectric output voltage peaks, thus proving material sensing capability. A maximum average output power density of 2.4nW/cm2 was calculated. Such interesting properties make sponge-like ZnO a promising smart material for sensing and energy harvesting applications.