Pump Density Research Articles

Two types of stimulated emission in HPHT diamond with a high concentration of NV centers

The paper presents the results of experimental observation of two types of stimulated emission (SE) under pulsed laser pumping at 532 nm in diamond with NV centers. A comprehensive spectroscopic characterization of multisectorial HPHT diamond plate was performed. At low pumping power, the stimulated emission from NV¯ centers was recorded as a broad (≥80 nm wide) band with a maximum at 706 nm in the {111} and {311} sectors of the diamond plate. As the pump power increased in the {111} sector, narrow-band stimulated emission (<10 nm wide) was detected, with a maximum at 716 nm and a luminescence impulse duration of 1.5–3 ns. As the pump density increased, a fine structure in the spectrum of narrow-band stimulated emission was revealed for the first time. The concentration of NV¯ centers in the {111} and {311} growth sectors was ≈10 ppm. However, there were considerable differences in the concentrations of C (35 and 3.5 ppm) and C+ centers (6.1 and 3.2 ppm, respectively). It was demonstrated that the presence of a high concentration of NV¯ centers is not the only necessary condition for the initiation of narrow-band SE in the 710–720 nm range. In the {311} sector, lighting at 360, 405, and 488 nm reduced the concentration of NV¯ centers by 15 % while increasing the concentration of C+ centers in the {311} sector. This effect is weak in the {111} sector. The authors suggested a model for narrow-band SE at the transition Valence Band → C+ with charge-state conversion of C↔C+ and NV0↔NV¯ centers. Further research on the dynamic processes is required in order to a detailed understanding of the operation of NV centers in diamond during SE generation.

Grain size control in quasi-two-dimensional perovskite thin film via intermediate phase engineering for efficient bound exciton generation

AbstractQuasi-two dimensional (2D) perovskites have emerged as a promising class of materials due to their remarkable photoluminescence efficiency, which stems from their exceptionally high exciton binding energies. The spatial confinement of excitons within smaller grain sizes could enhance the formation of biexcitons leading to higher radiative recombination efficiency. However, the synthesis of high-quality quasi-2D perovskite thin films with controllable grain sizes remains a challenging task. In this study, we present a facile method for achieving quasi-2D perovskite thin films with controllable grain sizes ranging from 500 to 900 nm. This is accomplished by intermediate phase engineering during the film fabrication process. Our results demonstrate that quasi-2D perovskite films with smaller grain sizes exhibit more efficient bound exciton generation and a reduced stimulated emission threshold down to 15.89 µJ cm−2. Furthermore, femtosecond transient absorption measurements reveal that the decay time of bound excitons is shorter in quasi-2D perovskites with smaller grain sizes compared to that of those with larger grains at the same pump density, which is 230.5 ps. This observation suggests a more efficient exciton recombination process in the smaller grain size regime. Our findings would offer a promising approach for the development of efficient bound exciton lasers.

Enhanced cone-shaped lasing from cholesteric liquid crystals.

Strong conical lasing in the violet-blue range of the spectrum from dye doped cholesteric liquid crystals is obtained. In contrast to the previously reported cases, the cone laser emission is sharply increased at the local maximums of the luminescence peaks of the dyes. Besides that, for obtaining the cone lasing strong focusing of the pumping beam is not required. Extremely low pump density is achieved for the cholesteric liquid crystal lasers. It is important that the cone lasing can be observed without simultaneous manifestation of any other laser emissions.

Experimental studies of the characteristics of a resonant leader emitter with a single-pass amplifier

The results of experimental studies of the energy and spatial characteristics of the lidar transmitter, built according to the generator-amplifier scheme based on an organic dye with tube pumping, are presented. The choice of a single-pass traveling wave amplifier used in the experiments was determined by preserving the spectral purity of the radiation. When constructing a lidar emitter according to the generator-amplifier scheme under conditions of constant pumping density, the problem arises of choosing the ratio between the length of the active element of the generator and the length of the active medium of the traveling wave amplifier, which would ensure the maximum efficiency of the entire emitter. The main task of the work was the experimental verification of the results of theoretical studies of the narrow-band emitter of the resonant lidar in order to determine the factors affecting the choice of the ratio of the lengths of the active elements of the generator and the amplifier based on the organic dye rhodamine 6Zh with tube pumping with limited total length. The amount of effective radiated energy was used as the main criterion for evaluating the efficiency of the generator-amplifier system. The experimental results confirm the theoretical conclusions that there are optimal ratios of the lengths of the generator and the amplifier, at which the effective radiation energy is maximal. The limiting length of the amplifier and the energy of the emitter built according to the generator-amplifier circuit are limited by the increase in the intensity of the radiation amplified along the active element, as well as the increase in the intensity of the amplified noise.

Highly inclined light sheet allows volumetric super-resolution imaging of efflux pumps distribution in bacterial biofilms

Bacterial biofilms are highly complex communities in which isogenic bacteria display different gene expression patterns and organize in a three-dimensional mesh gaining enhanced resistance to biocides. The molecular mechanisms behind such increased resistance remain mostly unknown, also because of the technical difficulties in biofilm investigation at the sub-cellular and molecular level. In this work we focus on the AcrAB-TolC protein complex, a multidrug efflux pump found in Enterobacteriaceae, whose overexpression is associated with most multiple drug resistance (MDR) phenotypes occurring in Gram-negative bacteria. We propose an optical method to quantify the expression level of the AcrAB-TolC pump within the biofilm volume at the sub-cellular level, with single-molecule sensitivity. Through a combination of super-resolution PALM with single objective light sheet and precision genome editing, we can directly quantify the spatial distribution of endogenous AcrAB-TolC pumps expressed in both planktonic bacteria and, importantly, within the bacterial biofilm volume. We observe a gradient of pump density within the biofilm volume and over the course of biofilm maturation. Notably, we propose an optical method that could be broadly employed to achieve volumetric super-resolution imaging of thick samples.

Topological valley Hall polariton condensation.

A photonic topological insulator features robust directional propagation and immunity to defect perturbations of the edge/surface state. Exciton-polaritons, that is, the hybrid quasiparticles of excitons and photons in semiconductor microcavities, have been proposed as a tunable nonlinear platform for emulating topological phenomena. However, mainly due to excitonic material limitations, experimental observations so far have not been able to enter the nonlinear condensation regime or only show localized condensation in one dimension. Here we show a topological propagating edge state with polariton condensation at room temperature and without any external magnetic field. We overcome material limitations by using excitonic CsPbCl3 halide perovskites with a valley Hall lattice design. The polariton lattice features a large bandgap of 18.8 meV and exhibits strong nonlinear polariton condensation with clear long-range spatial coherence across the critical pumping density. The geometric parameters and material composition of our nonlinear many-body photonic system platform can in principle be tailored to study topological phenomena of other interquasiparticle interactions.

Research on Energy Loss of Optimization of Inducer–Impeller Axial Fit Dimensions Based on Wave-Piercing Theory

With the development of modern fluid machinery, the energy density of pumps is gradually being improved, and at the same time, higher demands are being placed on the cavitation performance, hence the introduction of the inducer and centrifugal impeller to form a dynamic–dynamic series structure. However, there are strict constraints on the axial size of pumps in fields such as firefighting and aerospace. The traditional empirical formula no longer satisfies the need to fit the axial dimensions between the induced wheel and the impeller at high velocities. Therefore, based on the wave-piercing theory, the drag reduction coefficient is introduced to explore the optimal axial fit size from the perspective of energy characteristics. This paper focuses on the influence of the inducer’s wake on the energy characteristics of downstream impellers, and conducts the following research: by adjusting the axial matching dimensions between the upstream inducer and the centrifugal impeller in the initial model, ten sets of axial distance models with matching dimensions of KD are designed, and the drag reduction coefficient is embedded to determine the optimal axial distance. The results show that the optimal axial distance is 0.2D, which is far lower than the axial distance value of 0.42D obtained from the traditional empirical formula for axial matching dimensions. Meanwhile, this paper uses tangential velocity, the inlet flow angle of the impeller, entropy production theory, and other indicators to analyze the internal energy loss of the high-speed vehicular fire pumps one by one. All of them confirm that the impeller in the high-speed vehicular fire pump has the lowest energy loss and optimal performance at an axial distance of 0.2D. Specifically, at this axial distance, the head can reach 259 m, and the hydraulic efficiency is as high as 83.62%. Thus, the feasibility of determining the axial placement of the impeller using the drag coefficient is validated. This research provides new insights into determining the axial coordination dimensions between the inducer and the impeller.

Energy-based high frequency oscillation control of linear drives

Linear electromagnetic actuators realizing periodic oscillations have gained significant importance in the compressor and pump technology. This is due to the need of compact drive units to increase the power density of modern pumps and compressors. This work presents an energy-based control approach for harmonic oscillations of linear electromagnetic drives and analyzes the functionality and performance of the oscillation control for periodic actuator movements up to 250 Hz. To obtain a more robust control behavior, the control structure needs to be decoupled, with an amplitude and phase component using a periodical harmonic carrier function. This approach avoids a standstill of the actuator by constantly triggering an oscillation at the fundamental frequency of the mechanical system. The presented control approach is especially beneficial for oscillatory systems which need to adapt their oscillation frequency to mechanical loads.

High-Frequency Shift and Extension of the Terahertz Radiation Spectrum up to 10 THz During Optical Rectification of High-Power Few-Cycle Near-Infrared Femtosecond Pump Radiation in a BNA Crystal

The generation of terahertz radiation in a BNA crystal pumped by 1.24-µm femtosecond laser radiation from a Cr:forsterite laser system with a pulse duration of 100 and 35 fs and a pump density of 10 mJ/cm2 has been realized. The achieved generation efficiency is 0.1%. It is found that a decrease in the pump pulse duration from 100 to 35 fs leads to the generation of high-frequency components in the ranges of 2.5–6.5 THz and 9‒10.5 THz in the generated radiation spectrum. Simulation of the terahertz radiation generation based on the solution of Maxwell’s equations by the finite-difference time-domain method has made it possible to adequately describe the measured spectra. The generation of broadband high-frequency terahertz radiation in the BNA crystal pumped by the Cr:forsterite laser system allows one to consider this schematic as an alternative to sources based on the BNA crystal pumped by a Ti:sapphire laser system.

High-Frequency Shift and Extension of the Terahertz Radiation Spectrum up to 10 THz During Optical Rectification of High-Power Few-Cycle Near-Infrared Femtosecond Pump Radiation in a BNA Crystal

The generation of terahertz radiation in a BNA crystal pumped by 1.24-µm femtosecond laser radiation from a Cr:forsterite laser system with a pulse duration of 100 and 35 fs and a pump density of 10 mJ/cm2 has been realized. The achieved generation efficiency is 0.1%. It is found that a decrease in the pump pulse duration from 100 to 35 fs leads to the generation of high-frequency components in the ranges of 2.5–6.5 THz and 9‒10.5 THz in the generated radiation spectrum. Simulation of the terahertz radiation generation based on the solution of Maxwell’s equations by the finite-difference time-domain method has made it possible to adequately describe the measured spectra. The generation of broadband high-frequency terahertz radiation in the BNA crystal pumped by the Cr:forsterite laser system allows one to consider this schematic as an alternative to sources based on the BNA crystal pumped by a Ti:sapphire laser system.

Development of a urinometer for automatic measurement of urine flow in catheterized patients.

Urinary flow measurement and colorimetry are vital medical indicators for critically ill patients in intensive care units. However, there is a clinical need for low-cost, continuous urinary flow monitoring devices that can automatically and in real-time measure urine flow. This need led to the development of a non-invasive device that is easy to use and does not require proprietary disposables. The device operates by detecting urine flow using an infrared barrier that returns an unequivocal pattern, and it is capable of measuring the volume of liquid in real-time, storing the history with a precise date, and returning alarms to detect critical trends. The device also has the ability to detect the color of urine, allowing for extended data and detecting problems in catheterized patients such as hematuria. The device is proposed as an automated clinical decision support system that utilizes the concept of the Internet of Medical Things. It works by using a LoRa communication method with the LoRaWAN protocol to maximize the distance to access points, reducing infrastructure costs in massive deployments. The device can send data wirelessly for remote monitoring and allows for the collection of data on a dashboard in a pseudonymous way. Tests conducted on the device using a gold standard medical grade infusion pump and fluid densities within the 1.005 g/ml to 1.030 g/ml urine density range showed that droplets were satisfactorily captured in the range of flows from less than 1 ml/h to 500 ml/h, which are acceptable ranges for urinary flow. Errors ranged below 15%, when compared to the values obtained by the hospital infusion pump used as gold standard. Such values are clinically adequate to detect changes in diuresis patterns, specially at low urine output ranges, related to renal disfunction. Additionally, tests carried out with different color patterns indicate that it detects different colors of urine with a precision in detecting RGB values <5%. In conclusion, the results suggest that the device can be useful in automatically monitoring diuresis and colorimetry in real-time, which can facilitate the work of nursing and provide automatic decision-making support to intensive care physicians.

What determines the optimal pharmacological treatment of atrial fibrillation? Insights from in silico trials in 800 virtual atria.

The best pharmacological treatment for each atrial fibrillation (AF) patient is unclear. We aim to exploit AF simulations in 800 virtual atria to identify key patient characteristics that guide the optimal selection of anti-arrhythmic drugs. The virtual cohort considered variability in electrophysiology and low voltage areas (LVA) and was developed and validated against experimental and clinical data from ionic currents to ECG. AF sustained in 494 (62%) atria, with large inward rectifier K+ current (IK1 ) and Na+ /K+ pump (INaK ) densities (IK1 0.11±0.03 vs. 0.07±0.03 SmF-1 ; INaK 0.68±0.15 vs. 0.38±26 SmF-1 ; sustained vs. un-sustained AF). In severely remodelled left atrium, with LVA extensions of more than 40% in the posterior wall, higher IK1 (median density 0.12±0.02 SmF-1 ) was required for AF maintenance, and rotors localized in healthy right atrium. For lower LVA extensions, rotors could also anchor to LVA, in atria presenting short refractoriness (median L-type Ca2+ current, ICaL , density 0.08±0.03 SmF-1 ). This atrial refractoriness, modulated by ICaL and fast Na+ current (INa ), determined pharmacological treatment success for both small and large LVA. Vernakalant was effective in atria presenting long refractoriness (median ICaL density 0.13±0.05 SmF-1 ). For short refractoriness, atria with high INa (median density 8.92±2.59 SmF-1 ) responded more favourably to amiodarone than flecainide, and the opposite was found in atria with low INa (median density 5.33±1.41 SmF-1 ). In silico drug trials in 800human atria identify inward currents as critical for optimal stratification of AF patient to pharmacological treatment and, together with the left atrial LVA extension, for accurately phenotyping AF dynamics. KEY POINTS: Atrial fibrillation (AF) maintenance is facilitated by small L-type Ca2+ current (ICaL ) and large inward rectifier K+ current (IK1 ) and Na+ /K+ pump. In severely remodelled left atrium, with low voltage areas (LVA) covering more than 40% of the posterior wall, sustained AF requires higher IK1 and rotors localize in healthy right atrium. For lower LVA extensions, rotors can also anchor to LVA, if the atria present short refractoriness (low ICaL ) Vernakalant is effective in atria presenting long refractoriness (high ICaL ). For short refractoriness, atria with fast Na+ current (INa ) up-regulation respond more favourably to amiodarone than flecainide, and the opposite is found in atria with low INa . The inward currents (ICaL and INa ) are critical for optimal stratification of AF patient to pharmacological treatment and, together with the left atrial LVA extension, for accurately phenotyping AF dynamics.

Localized Bound Multiexcitons in Engineered Quasi-2D Perovskites Grains at Room Temperature for Efficient Lasers.

Reducing the excitation threshold to minimize the Joule heating is critical for the realization of perovskite laser diodes. Although bound excitons are promising for low threshold laser, how to generate them at room temperature for laser applications is still unclear in quasi-2D perovskite-based devices. In this work, via engineering quasi-2D perovskite PEA2 (CH3 NH3 )n -1 Pbn Br3 n +1 microscopic grains by the anti-solvent method, room-temperature multiexciton radiative recombination is successfully demonstrated at a remarkably low pump density of 0.97 µJ cm-2 , which is only one-fourth of that required in 2D CdSe nanosheets. In addition, the well-defined translational momentum in quasi-2D perovskite grains can restrict the Auger recombination which is detrimental to radiative emission. Furthermore, the quasi-2D perovskite grains are favorable for increasing binding energies of excitons and biexcitons and so as the related radiative recombination. Consequently, the prepared <n= 8> phase quasi-2D perovskite film renders a threshold of room-temperature stimulated emission as low as 13.7 µJ cm-2 , reduced by 58.6% relative to the amorphous counterpart with larger grains. The findings in this work are expected to facilitate the development of solution-processable perovskite multiexcitonic laser diodes.

Research progress on key factors of dielectric-barrier discharge plasma for wastewater treatment

Plasma treatment of wastewater is known as a new advanced oxidation process (AOP), which has attracted extensive attention. Dielectric barrier discharge plasma has the characteristics of no vacuum pumping and high electron number density. It has outstanding application value in various forms of plasma. There are many coupling factors that affect the characteristics of dielectric barrier discharge plasma and the effect of wastewater treatment. Optimizing the key parameters is of great significance to improve the treatment efficiency and reduce the treatment cost. This paper introduces the principle, experimental device, potential advantages and application value of dielectric barrier discharge, summarizes the influence rules of key factors such as high voltage power supply characteristics, electrode configuration, carrier gas and reactor design on the characteristics of organic pollutant wastewater treatment by dielectric barrier discharge plasma. The optimization and matching of multiple factors are important problems. This paper provides a useful reference for the engineering application of plasma technology for wastewater treatment.

Experimental studies of a lidar emitter built according to the oscillator-amplifier scheme

The results of experimental studies of the energy characteristics of the leader transmitter built according to the lamp-pumped organic-dye oscillator-amplifier scheme are presented. When constructing the lidar emitter according to the oscillator-amplifier scheme under conditions of constant pump density, the problem arises of choosing the ratio between the length of the active element of the generator and the length of the active medium of the traveling wave amplifier, which ensures the maximum efficiency of the entire emitter. The main objective of the work was experimental verification of the results of theoretical studies in order to determine the factors influencing the choice of the ratio of the lengths of the active elements of the generator and amplifier based on the organic dye rhodamine 6G with lamp pumping with their limited total length.&#x0D; The results of the experiments confirm the theoretical conclusions that there are optimal ratios of the lengths of the generator and amplifier, at which the radiation energy is maximum. The limiting length of the amplifier and the energy of the emitter, built according to the scheme, the oscillator-amplifier are limited due to an increase in the intensity of the radiation that is amplified along the active element, as well as an increase in the intensity of the amplified noise.

All-Optical Control of Rotational Exciton Polaritons Condensate in Perovskite Microcavities

Exciton polariton condensation is a macroscopic quantum state that can be efficiently controlled by an external field through a nonlinear interaction. In an annular potential landscape, a rotational polariton flow with different orbit indexes can be created spontaneously. Control of their superposition states with symmetry broken is of fundamental interest for exotic quantum states. By adopting the nonresonant ring-shaped pumping in a planar perovskite microcavity, we demonstrate the linear coupled counter-rotating polariton states with ordered phase changes and a vortex pairs-petal state at the condensed threshold. The azimuthal indices and inherent flowing velocity can be well controlled by the diameter of the pumping ring and the detuning energy. At high pump density, the petal state becomes unstable and a single vortex generates, indicating the role of the polariton–polariton interaction and exciton depletion in controlling the superposition of the rotational polariton flow. Broken cylindrical symmetry is realized by a pumping ring with radial slots and the consequent dark soliton. An additional phase jump and fractional orbit index of polariton rotation can thus be obtained. Our results suggest the efficient all-optical control of rotational polariton flow and their superposition states with a flexible diameter and a broken cylindrical symmetry at room temperature, which is promising for practical polaritonic circular current-based applications with topological and chiral properties.

Optically Controlling Broadband Terahertz Modulator Based on Layer-Dependent PtSe2 Nanofilms

In this paper, we propose an optically controlling broadband terahertz modulator of a layer-dependent PtSe2 nanofilm based on a high-resistance silicon substrate. Through optical pump and terahertz probe system, the results show that compared with 6-, 10-, and 20-layer films, a 3-layer PtSe2 nanofilm has better surface photoconductivity in the terahertz band and has a higher plasma frequency ωp of 0.23 THz and a lower scattering time τs of 70 fs by Drude-Smith fitting. By the terahertz time-domain spectroscopy system, the broadband amplitude modulation of a 3-layer PtSe2 film in the range of 0.1-1.6 THz was obtained, and the modulation depth reached 50.9% at a pump density of 2.5 W/cm2. This work proves that PtSe2 nanofilm devices are suitable for terahertz modulators.

Recovery of Calcium from Reaction Fly Ash

Reaction fly ash contains a large number of harmful substances, so it is usually solidified and buried in landfills. To improve the problem of insufficient landfill space, this study recovers CaOH from reaction fly ash to achieve mass and volume reduction. The leachate obtained by leaching the reaction fly ash with de-ionized water and 2N hydrochloric acid was used in the experiments, respectively. The volume reduction with 2N hydrochloric acid had better performance than de-ionized water, representing more than 90%. The leaching efficiency of Ca reached 21.06% with de-ionized water for 20 min at a condition of 25 °C and 7 mL/g pump density. The chemical precipitation with NaOH was conducted immediately after the completion of the leaching experiment, with a precipitation efficiency of CaOH reaching 98.55%. The leaching efficiency of Ca reached 70.26% with 2N hydrochloric acid for 30 min at a condition of 25 °C and 10 mL/g pump density. The chemical precipitation with NaOH and ion exchange with IRC748 were conducted, respectively, after the completion of the leaching experiment. After two precipitations, the precipitation efficiency of CaOH was 99.93%. The precipitation efficiency and purity of Ca after ion exchange separation were 99.90% and 98.91%, respectively. This work provided an effective approach to recover CaOH from reaction fly ash and accomplished volume reduction at the same time.

Tissue-specific differences and temperature-dependent changes in Na,K-ATPase of the roach (Rutilus rutilus)

Na,K-ATPase activity is vital for virtually all cells of the animal body and the major consumer of cellular energy. However, Na,K-ATPase activity, the number of Na+ pump units, the catalytic rate of the pump, and their responses to thermal acclimation in different tissues of the same fish species have been seldom measured. Therefore, roach (Rutilus rutilus), eurythermal freshwater fish, was acclimated at 4 °C (cold-acclimated, CA) and 18 °C (warm-acclimated, WA), and the Na+ pump density and the temperature-dependence of Na,K-ATPase activity were determined in the heart, gills, kidney and brain. There were prominent tissues specific differences in Na,K-ATPase activity. The activity was highest in the brain (100%), whereas the activity of renal, branchial and cardiac enzymes was 55%, 9%, and 4% of the brain activity in the WA roach at 25 °C. The corresponding values for brain, kidney, gills and heart of the CA fish at 25 °C were 100%, 56%, 5% and 4%, respectively. The number of Na,K-ATPase α-subunits, determined by [3H]ouabain binding, strongly correlated with the Na,K-ATPase activity at R2 values of 0.99 and 0.85 for WA and CA fish, respectively. Acclimation to cold, increased the number of Na,K-ATPase α-subunits in the heart, kidney and brain (P < 0.05), but this did not appear as an increase in Na,K-ATPase activity. In the gills, Na,K-ATPase α-subunits did not change in cold-acclimation, but Na,K-ATPase activity was depressed. Although tissue-specific differences in Na,K-ATPase activity are largely determined by the density of α-subunits, differences in Na,K-ATPase activity within the same tissue due to temperature acclimation involve also other factors in addition to the number of Na+ pump units.

A Disposable Electromagnetic Bi-Directional Micropump Utilizing a Rotating Multi-Pole Ring Magnetic Coupling.

Electromagnetic bi-directional micropumps (EMBM) are indispensable for the development of portable devices which enable fluid transportation in forward and reverse directions. However, the high disposal cost of rare-earth magnets attached to the fluidic part and the low pump density due to multiple motors limit their practical application in disposable multi-channel microfluidic applications such as droplet-based oscillatory-flow (DBOF) rapid PCR amplification. Therefore, this paper presented a low-cost, disposable, high-pump-density EMBM. To reduce the disposal cost, we separated the magnets from the disposable fluidic part and used cylindrical holes to store and guide the magnet, which resulted in the ability to reuse all the magnets. To increase the pump density, we used the combination of one motor and one multi-pole ring magnet to drive several channels simultaneously. A proof-of-concept prototype with a pump density of 0.28 cm−2 was fabricated and experimentally evaluated. The fabricated micropump exhibited a maximum flow rate of 0.86 mL/min and a maximum backpressure of 0.5 kPa at a resonant frequency around 50 Hz. The developed multi-channel micropump with reusable magnets is highly beneficial to the development of low-cost and high-throughput rapid PCR amplification microchips and therefore can have a significant impact on timely infectious disease recognition and intervention.