Average Transit Time Research Articles

Perfusion computer tomography of the kidneys. Research technique. Perfusion indicators in the norm: case-control

INTRODUCTION: Perfusion computed tomography (PCT) is a contrast research technique that allows one to assess blood flow in the cortical and medulla layers of the renal parenchyma at the level of the microcirculatory bed, the influence of additional renal vessels and stenoses of the renal arteries on hemodynamics in the renal parenchyma.OBJECTIVE: To optimize the technique of perfusion computed tomography of the kidneys. Determine the most informative indicators of perfusion in the renal parenchyma in the norm. Assess the relationship between perfusion parameters and the number of renal vessels, the presence of renal artery stenosis.MATERIALS AND METHODS: PCT was performed in 46 patients with no anamnestic and clinical laboratory data on kidney disease who were undergoing examination for other pathological conditions, including 35 patients aged from 20 to 90 years (average age — 63.1 years) without hemodynamically significant stenosis and 11 patients aged from 64 to 94 years (mean age 80.3 years) with renal artery stenosis of 50% or higher. Perfusion indices were calculated using maximum slope and deconvolution algorithms, kinetic curves were plotted on a time-density graph, and color parametric maps.RESULTS: A quantitative assessment of perfusion parameters in the cortical and medulla of the kidneys, a qualitative analysis of the state of its parenchyma on color parametric maps, and the shapes of kinetic curves on the time-density graph were analyzed. Changes in perfusion parameters were established depending on the age, number and condition of the renal vessels.DISCUSSION: In the renal cortical layer, there was a predominance of indicators of blood flow velocity (BF), blood flow volume (BV), the rate of increase in the density of the contrast agent (CM) in the tissue (MSI), capillary wall permeability (PS) and lower values of the average transit time of the contrast agent (MTT) and the time to reach the maximum contrast agent density in the tissue (TTP) in comparison with the medulla. On the color parametric maps BF, BV, MSI, the cortical layer was characterized by intense red coloring, the medulla — yellow-green, on the TTP map green and blue coloring of the layers was determined, respectively. In elderly patients, there was a decrease in BF, BV with a concomitant lengthening of TTP in the cortical layer without changes in coloring on color parametric maps. On the density-time graph, the kinetic curve of the cortical layer was characterized by the appearance of a peak 10 seconds after the onset of the peak value in the abdominal aorta with further continuation of the curve in the form of a plateau; the kinetic curve of the medulla was characterized by a gradual moderate rise in the curve from 15 seconds after the start of scanning without the formation of peaks values.CONCLUSION: PCT is an informative method for quantitative and qualitative assessment of perfusion in the renal parenchyma.

Altimeter-derived poleward Lagrangian pathways in the California Current System: Part 1

We use altimeter-derived geostrophic velocities, with and without the addition of surface Ekman transports, to create trajectories for virtual parcels in the California Current System (CCS). The goal is to investigate the poleward transport of passive water parcels in the surface 50–100 m of the nominally equatorward system. Motivation for the study is provided by observations of anomalous biomass of copepods with warm water affinities along the Newport Hydrographic Line off central Oregon (44.7°N) during El Niño years, as well as during and following the 2014–2016 marine heat wave. By backward tracking virtual parcels from 44.7°N, we find that the most distant source of passive water parcels in the upper ocean during a one-year period of travel is from within the Southern California Bight (SCB), north of 30°N. To make that journey, parcels use the Inshore Countercurrent off southern and central California during summer–winter and the Davidson Current off northern California and Oregon during autumn–winter. The inclusion of small-scale eddy diffusion usually increases the number of parcels that reach more northern latitudes, while the inclusion of Ekman velocities more often reduces those numbers. Even so, parcels can travel from the SCB to central Oregon in either the Ekman layer or beneath it in the geostrophic flow. Using backward tracking, we find that parcels arrive at 44.7°N most often in winter–spring, least often in autumn. They arrive from within the large-cape region off northern California (41°–42°N) during all years and all months, from just south of the large-cape region (38°–39°N) during most years but seldom in autumn, from south of Monterey Bay along central California (36°N) and within the SCB (34.5°N) during a third (or less) of the years and only in winter-spring. The shortest average transit times are found in winter: for parcels reaching 44.7°N in February, the average transit time is 2 months for parcels coming from 41°–42°N, 4 months for parcels coming from 38°–39°N, and 5–6 months or more for parcels coming from south of 36°N. Transit times increase as the arrival time progresses from winter to autumn. The longest average transit times are for parcels reaching central Oregon in autumn (9–12 months in October for parcels coming from south of 39°N). This makes the journey a multi-generational task for the copepods. Interannual variability in the observed southern copepod species biomass off central Oregon correlates highly with years when more virtual parcels from the south reach central and northern Oregon, providing increased confidence in the results found with the altimeter-derived parcel trajectories.

Experimental constraints on barium isotope fractionation during adsorption–desorption reactions: Implications for weathering and erosion tracer applications

Constraining the processes that fractionate barium isotopes is essential for utilising barium isotope ratios as environmental tracers. Barium concentration measurements from soils, rivers, and estuaries demonstrate that adsorption–desorption reactions significantly influence the distribution of fluid–mobile barium at the Earth’s surface, potentially driving isotopic fractionation. To quantify the direction and magnitude of isotopic fractionation resulting from these reactions, a riverine and an estuarine series of batch experiments were conducted using environmentally important adsorbent minerals and surface waters. Himalayan river sediment and water samples were used to validate the experimental results.Adsorption–desorption reactions were found to be rapid, relative to the average transit time of sediment and water in catchments, and largely reversible. The direction and magnitude of isotopic fractionation in the riverine experiment series were consistent with the riverine field samples (preferential adsorption of the lighter isotopes). The reaction rate, reversibility, and magnitude of isotopic fractionation were found to depend primarily on the mineral. Experiments performed with iron oxyhydroxides (goethite and ferrihydrite) resulted in a greater degree of fractionation compared to clay minerals (kaolinite and montmorillonite). Estuarine experiments, designed to simulate sediment passage through a salinity gradient, demonstrated a high degree of reversibility, with 77% to 94% of adsorbed barium desorbed upon the addition of seawater to freshwater-equilibrated clay minerals.The results of the estuarine experiments suggest that barium isotope ratios measured in marine paleo-archives (e.g., corals) will reflect both the adsorbed and dissolved freshwater barium inputs to the ocean. The combined findings of this study indicate that the chemical and isotopic behaviour of barium differs from more conventional group 1 and 2 metal isotope systems due to a significant proportion of barium released from bedrock dissolution partitioning to mineral surfaces, rapid reaction rates between fluid–mobile phases, and a high degree of reaction reversibility. Consequently, riverine barium isotope ratios are likely to provide unique insights into the complex array of terrestrial weathering and erosion processes that sustain life on Earth.

Comprehensive analysis of characteristics of dry–wet events and their transitions in Uttar Pradesh, India

Understanding the occurrence and characteristics of dry and wet events is crucial for effective disaster prevention, resource management, and risk reduction in vulnerable regions. This study analyzed the spatiotemporal patterns of dry–wet events and their transition characteristics in Uttar Pradesh, India. The standardized precipitation evapotranspiration index (SPEI) at a monthly timescale was utilized to identify hotspot regions vulnerable to concurrent and frequent dry and wet events and their transitions. The severity, duration, and intensity of dry and wet events were characterized with the run theory over SPEI time series data from 18 synoptic stations in Uttar Pradesh over 48 years (1971–2018), sourced from the Indian Institute of Tropical Meteorology and the India Meteorological Department. Multiple assessment methods were utilized to examine the interaction of these extreme events, considering characteristics such as wet–dry ratio, average transition time, and rapid transition times from wet to dry events and from dry to wet events. Average wet durations ranged from 1.27 to 1.58 months, and average dry durations ranged from 1.29 to 1.82 months. Rapid transition times from dry to wet events ranged from 2.5 to 4.1 months, and those for wet-to-dry events ranged from 2.1 to 5.3 months. The eastern region experienced a significantly high number of dry events, while the western and Bundelkhand regions experienced more intense dry events. In contrast, the eastern region had intense wet events. This research on the occurrence of dry–wet events and their transitions can provide valuable insights for government decision-making and disaster prevention and reduction efforts.

Adaptive Locomotion Transition Recognition With Wearable Sensors for Lower Limb Robotic Prosthesis

Locomotion transition recognition with external disturbances is a key issue in lower limb robotic prostheses. Redonning the prosthetic socket and individual differences are encountered frequently in daily life. They change the feature distribution and further fail the previously trained recognition model. To bridge the technical gap between laboratory validation and practical demands, researchers need to construct an adaptive recognition method with high accuracy, quick response, time-efficient calibration, and minimal interference to the human body. Our study developed an adaptive recognition algorithm based on two miniaturized inertial sensors (anterior thigh and forefoot) and a foot pressure sensor, which can easily be integrated into the prosthesis. The algorithm fused probability-based fuzzy classifiers, which took heuristic-based features as inputs with a dynamic-time-warping-based automatic template generation block. It enables the recognition model to quickly fit the parameters for an untrained mode after external disturbances. We validated the proposed adaptive recognition method on 13 healthy subjects, performing 18 motion transitions with random interday intervals and across user evaluation, both offline and online. Even with the data of one subject as the prior knowledge, the other subjects produced an average accuracy of 98.04% and an average transition time latency of −180.99 ms without manual training in interday and intersubject uses. We also tested the method on two subjects using robotic prostheses, one person with a transfemoral amputation and the other person with a transtibial amputation. The average accuracy was still as high as 98.06% (transfemoral) and 100% (transtibial) without manual calibration after seven days of intervals. The results proved that the adaptive recognition method is robust to sensor redonning and user changes. Compared with the state-of-the-art methods, our study makes a further step toward the practical use of robotic prostheses. Future studies will be conducted to implement the algorithm on the robotic prosthesis for more extensive tests.

A study of DNA transfers onto plastic packets placed in personal bags.

The ability to detect low level DNA brings with it the uncertainty of whether the detected DNA is a result of transfer. To address this uncertainty, a simulation study was conducted in which a mock illicit drug packet was placed into the personal bags of individuals. When the average transit time of the packets was increased from around 2 h to more than 14 h, the percentage of the DNA profiles recovered from the packets which could be attributed to the individuals increased greatly from 5.3% to 48.6%. We found that drug packers who were poor shedders could not be included as contributors to the DNA profiles from the drug packets at all and there was a higher chance that individuals other than themselves could be included as contributors to the DNA profile recovered from drug packets. We also found that it was equally likely that the drug packers who had direct contact with the drug packets and bag owners who did not, could be included as contributors to the DNA profiles recovered from the packets. The results in this study highlight the importance of taking into consideration the transit time of drug packet, the shedder status of the alleged packer and the history of an item, when evaluating DNA evidence in the context of illicit drug activities.

Revitalisasi Sistem ATS: Integrasi Smart Relay dan Teknologi Otomatisasi Suhu.

This research delves into the intricacies of an Automatic Transfer Switch (ATS) system anchored on the Zelio SR2A101BD smart relay. The exploration primarily centers on the functionality and performance metrics of the system's components, notably the PZEM-004T sensor for electrical data acquisition and the DS18B20 for temperature sensing. Through meticulous experimentation and testing, the research underscores the system's capability to seamlessly transition between primary (PLN) and secondary (PLTS) power sources during interruptions or failures. Utilizing the Zelio Soft 2 software as an analytical tool, the research gauges the system's efficiency and responsiveness. Noteworthy findings highlight an average transition time of 4.39 seconds from PLN to PLTS and 1.06 seconds in the opposite direction. This research culminates in affirming the ATS system's reliability and its potential as a pivotal component in modern electrical infrastructures.

Routing and charging optimization for electric bus operations

The transition to alternative energy sources and the adoption of on-demand operating modes in urban bus systems are crucial steps towards reducing carbon footprints and improving public transit services. This paper presents a two-phase approach for the collaborative optimization of charging schedules and passenger services, aimed at enhancing the operation of on-demand electric bus systems. First, we propose a label-setting dynamic programming algorithm that enables the efficient generation of bus-trips for each bus line in response to passenger requests. Second, we introduce a time–space network optimization model that facilitates integrated multiple bus-trip planning for the transit network, involving multiple bus lines and charging spots. The model selects bus-trips from various time–space arcs, which represent passenger carrying, bus deployment, and bus charging activities. To validate the effectiveness of our approach, we conduct a case study using real-world data from bus lines in Beijing, China. Computational results demonstrate that our approach can handle on-demand electric bus operations within minutes of solution time, efficiently serving over 2,000 passengers. Practically, our approach achieves a notable reduction in average transit time and effectively reduces the waste of public transit resources. The proposed approach can serve as a beneficial tool for decision-makers and operators seeking to enhance the performance and environmental impact of their electric bus systems.

Photopolymerization Inks for 3D Printing of Elastic, Strong, and Biodegradable Oral Delivery Devices

AbstractThree‐dimensional (3D) printing via vat photopolymerization is transforming the manufacturing paradigms of biomedical devices, offering tremendous advantages for the production of customized advanced drug delivery systems. However, the existing commercial inks often lack the ability to simultaneously provide elasticity, strength, and biodegradability. Herein, photopolymerizable inks based on poly(β‐aminoester) diacrylates and N‐vinyl pyrrolidone are used to address these limitations. These biodegradable polymers enable the digital light processing 3D printing of elastomers with adjustable elongation at break (103–762%), stress at failure (0.2–8.3 MPa), and hydrolysis rates ranging from 25 min to 80 days. The authors are able to synthesize a soft polymer that possess properties akin to natural latex, which can enhance its elastic modulus when subjected to high strains. It can withstand 762% stretch with a maximum strength of 8.3 MPa. In addition, this polymer demonstrates cytocompatibility and unique biodegradation properties under simulated gastrointestinal conditions (within hours at pH 6.8). By utilizing this elastomer, a prototype of an expandable oral drug delivery device that has the ability to degrade within the average transit time in the jejunum is manufactured. This study paves the way to leverage vat photopolymerization 3D printing in the creation of complex prototypes of biomedical devices where strength, elasticity and biodegradability are essential.

Post-Doc Competition (Knowledge Generation) ID 1985177

Background Heart Disease is the leading cause of death after spinal cord injury (SCI). Individuals with paraplegia develop hypertension and elevated arterial stiffness prior to their age matched peers. Overground exoskeleton training is becoming an increasingly prevalent form of exercise. In the general population, exercise training has been shown to reduce arterial stiffness. Recent RCT failed to show changes in arterial stiffness with arm ergometry or body weight supported treadmill training. Objectives The aim of this project is to determine the effect of Exoskeleton Exercise on changing arterial stiffness. Study Design The study setting will take place at a rehabilitation facility. The study will involve 34 sessions over the span of approximately 18-20 weeks. The key intervention utilized in the investigation will be an Overground EksoNR gait and balance training program. The primary outcome measure will be carotid-femoral pulse wave velocity (cfPWV) and secondary measures will include heart rate (HR), blood pressure (BP), waist circumference (WC), and oxygen saturation (SpO2). Statistical Analysis will involve mean changes at baseline, midway, and end of study. Methods The 34-session (2x/week for ∼18 weeks) rehabilitation protocol will focus on using the EksoNR for overground gait and balance activities. For measurement of cfPWV, two transcutaneous Doppler flowmeters will be used at the common carotid and femoral artery. To calculate cfPWV, the distance travelled by the pulse is divided by the average pulse transit time (PTT). Hypothesis The 18-week Exoskeleton Program would improve arterial stiffness (cfPWV) in individuals with chronic incomplete SCI/D.

Rapid Quenching of Galaxies at Cosmic Noon

The existence of massive quiescent galaxies at high redshift seems to require rapid quenching, but it is unclear whether all quiescent galaxies have gone through this phase and what physical mechanisms are involved. To study rapid quenching, we use rest-frame colors to select 12 young quiescent galaxies at z ∼ 1.5. From spectral energy distribution fitting, we find that they all experienced intense starbursts prior to rapid quenching. We confirm this with deep Magellan/FIRE spectroscopic observations for a subset of seven galaxies. Broad emission lines are detected for two galaxies, and are most likely caused by active galactic nucleus (AGN) activity. The other five galaxies do not show any emission features, suggesting that gas has already been removed or depleted. Most of the rapidly quenched galaxies are more compact than normal quiescent galaxies, providing evidence for a central starburst in the recent past. We estimate an average transition time of 300 Myr for the rapid quenching phase. Approximately 4% of quiescent galaxies at z = 1.5 have gone through rapid quenching; this fraction increases to 23% at z = 2.2. We identify analogs in the TNG100 simulation and find that rapid quenching for these galaxies is driven by AGNs, and for half of the cases, gas-rich major mergers seem to trigger the starburst. We conclude that these young massive quiescent galaxies are not just rapidly quenched, but also rapidly formed through a major starburst. We speculate that mergers drive gas inflow toward the central regions and grow supermassive black holes, leading to rapid quenching by AGN feedback.

Regional variability in intracerebral properties of NREM to REM sleep transitions in humans

Transitions between wake and sleep states show a progressive pattern underpinned by local sleep regulation. In contrast, little evidence is available on non-rapid eye movement (NREM) to rapid eye movement (REM) sleep boundaries, considered as mainly reflecting subcortical regulation. Using polysomnography (PSG) combined with stereoelectroencephalography (SEEG) in humans undergoing epilepsy presurgical evaluation, we explored the dynamics of NREM-to-REM transitions. PSG was used to visually score transitions and identify REM sleep features. SEEG-based local transitions were determined automatically with a machine learning algorithm using features validated for automatic intra-cranial sleep scoring (10.5281/zenodo.7410501). We analyzed 2988 channel-transitions from 29 patients. The average transition time from all intracerebral channels to the first visually marked REM sleep epoch was 8 s ± 1 min 58 s, with a great heterogeneity between brain areas. Transitions were observed first in the lateral occipital cortex, preceding scalp transition by 1 min 57 s ± 2 min 14 s (d = -0.83), and close to the first sawtooth wave marker. Regions with late transitions were the inferior frontal and orbital gyri (1 min 1 s ± 2 min 1 s, d = 0.43, and 1 min 1 s ± 2 min 5 s, d = 0.43, after scalp transition). Intracranial transitions were earlier than scalp transitions as the night advanced (last sleep cycle, d = -0.81). We show a reproducible gradual pattern of REM sleep initiation, suggesting the involvement of cortical mechanisms of regulation. This provides clues for understanding oneiric experiences occurring at the NREM/REM boundary.

Destinations and Pathways of the Indonesian Throughflow Water in the Indian Ocean

Abstract Passage of the Indonesian Throughflow (ITF) water through the Indian Ocean constitutes an essential section of the upper limb of the global ocean conveyor belt. Although existing studies have identified a major exit of the ITF water to the Atlantic Ocean through the Agulhas Current system, our knowledge regarding other possible destinations and primary pathways remains limited. This study applies the Connectivity Modeling System (CMS) particle tracking algorithm to seven model-based ocean current datasets. The results reveal a robust return path of the ITF water to the Pacific Ocean. The partition ratio between the Atlantic and Pacific routes is 1.60 ± 0.54 to 1, with the uncertainty representing interdataset spread. The average transit time across the Indian Ocean is 10–20 years to the Atlantic and 15–30 years to the Pacific. The “transit velocity” is devised to describe the three-dimensional pathways in a quantitative sense. Its distribution demonstrates that the recirculation structures in the southwestern subtropical Indian Ocean favor the exit to the Atlantic, while the Antarctic Circumpolar Current in the Southern Ocean serves as the primary corridor to the Pacific. Our analysis also suggests the vital impact of vertical motions. In idealized tracing experiments inhibiting vertical currents and turbulent mixing, more water tends to linger over the Indian Ocean or return to the Pacific. Turbulence mixing also contributes to vertical motions but only slightly affects the destinations and pathways of ITF water.

Features of application of fractal Gaussian noise type signals in telecommunication systems

Problem statement. At present, the properties of a separate type of pseudorandom signals such as fractal Gaussian noise remain insufficiently investigated. The existing discrete model of fractal Gaussian noise is characterized by the value of the Hurst exponent and the time scaling factor, the influence of which on the properties of fractal Gaussian noise is insufficiently investigated. The issue of synthesis of new types of fractal broadband signals of complex design, which can be used in noise-resistant telecommunication systems, is relevant. Objective. Based on the mathematical model of fractal Gaussian noise, investigate the effect of the time scaling factor on the statistical, correlation and energy properties of fractal Gaussian noise signals. Results. By the method of averaging over realizations the dependences of energy, correlation and statistical properties of signals of fractal Gaussian noise type, which can be used for coding information bits, on the time scaling factor were obtained. Practical significance. According to the results of research on the properties of fractal Gaussian noise, the regularities of the passage of self-similar flows of Internet traffic in the approximation that they are self-similar and are described by a mathematical model of fractal Gaussian noise are established. When the intensity is increased up to requests/hour, the results of modeling the average transit time of traffic through the system for flows with different types of distribution show significant differences in the value of the average transit time of each request.

Transit Time index (TTi) as an adaptation of the humification index to illustrate transit time differences in karst hydrosystems: application to the karst springs of the Fontaine de Vaucluse system (southeastern France)

Abstract. Transit time can be estimated thanks to natural tracers, but few of them are usable in the 0–6-month range. The main purpose of this work is to analyze the potential of the ratio of heavy- to light-weight organic compounds (the humification index (HIX); Ohno, 2002; Zsolnay et al., 1999) as a natural tracer of short transit time (Blondel et al., 2012). Critical analysis of former studies shows that although the link between HIX and transit time seems consistent, the whole methodological approach needs to be consolidated. Natural organic matter fluorescence from 289 groundwater samples from four springs and 10 flow points located in the unsaturated zone of the Vaucluse karst system is characterized by parallel factor analysis (PARAFAC) thanks to the excitation–emission matrix (EEM), thus (i) allowing for the identification of main fluorescent compounds of sampled groundwater and (ii) evidencing the inadequacy of HIX 2D emission windows to characterize groundwater organic matter. We then propose a new humification index called the Transit Time index (TTi) based on the Ohno (2002) formula but using PARAFAC components of heavy and light organic matter from our samples instead of 2D windows. Finally, we evaluate TTi relevance as a transit time tracer by (i) performing a detailed analysis of its dynamics on a selected spring (Millet) and (ii) comparing its mean value over karst springs of the Vaucluse karst system. Principal component analysis (PCA) of TTi and other hydrochemical parameters monitored at Millet spring put in relief the different ranges of transit time associated with the different organic matter compounds. PCA results also provide evidence that TTi can detect a small proportion of fast infiltration water within a mix, while other natural tracers of transit time provide no or less sensitive information. TTi distributions at monitored karst springs are consistent with relative transit times expected for the small-scale, short average transit time systems. TTi thus appears as a relevant qualitative tracer of transit time in the 0–6-month range where existing tracers fail and may remain applicable, even in the case of anthropic contamination thanks to PARAFAC modeling. Transforming it into quantitative information is a challenging task which may be possible thanks to intensive studies of organic matter degradation kinetics in natural waters with the help of radiogenic isotope usage or an artificial tracer test.

Stochastic approach to Markovian interrelationship assessment of solar activity indices

This paper employs a discrete-time Markov chain (DTMC) stochastic process to investigate a state/event based Markovian interrelationship between various solar activity indices (SAI) (including 10.7 cm solar radio flux (SF10.7), coronal index (CI), solar flare index (SFI) and total solar irradiance (TSI)) in relation to sunspot number (SSN). First, we applied the first order DTMC model as a first approximation to the total number of transitions between different states of SAI in order to estimate the probability of occurrence corresponding with each transition. Next, several DTMC descriptors like persistency, state dependency, stationarity, mean first passage time and entropy are derived from estimated transition probability matrices. These descriptors are very useful as they related to time series characteristics (like randomness, nature of cycles and predictability) within a stochastic dynamical system as well as crucial for checking the applicability of Markov chain method. Therefore, via the DTMC analysis and derived descriptors, this study found remarkable similarities in the formation of transition matrices and diagrams, significant 2-dimensional correlation values, robust self-communication behaviour among states, existence of dependent successive transitions and stationary nature of data throughout the space. Further, the resemblance in the average transit time from one state to another, probabilistically disordered symmetrical time series and existence of randomness in transition states has been observed. Therefore, results obtained in this paper provide a new insight to increase the level of knowledge of the possible linkage between underlying SAI that could be helpful in enhanced understanding of the potential future climate changes and other solar energy-related objectives.

How can Brewer–Dobson circulation trends be estimated from changes in stratospheric water vapour and methane?

Abstract. The stratospheric meridional overturning circulation, also referred to as the Brewer–Dobson circulation (BDC), controls the composition of the stratosphere, which, in turn, affects radiation and climate. As the BDC cannot be directly measured, one has to infer its strength and trends indirectly. For instance, trace gas measurements allow the calculation of average transit times. Satellite measurements provide information on the distributions of trace gases for the entire stratosphere, with measurements of particularly long temporal and dense spatial coverage available for stratospheric water vapour (H2O). Although chemical processes and boundary conditions confound interpretation, the influence of methane (CH4) oxidation on H2O in the stratosphere is relatively straightforward, and thus H2O is an appealing tracer for transport analysis despite these caveats. In this work, we explore how mean age of air trends can be estimated from the combination of stratospheric H2O and CH4 data, by carrying out a proof of concept within the model environment of the Chemical Lagrangian Model of the Stratosphere (CLaMS). In particular, we assess the methodological uncertainties related to the two commonly used approximations of (i) instantaneous stratospheric entry mixing ratio propagation and (ii) constant correlation between mean age and the fractional release factor of CH4. Performing various sensitivity studies with CLaMS, we test different methods of the mean age of air trend estimation, and we aim to provide simple and practical advice on the adjustment of the used approximations for obtaining more reliable mean age of air trends from the measurements of H2O and CH4. Our results show that the estimated mean age of air trends from the combination of stratospheric H2O and CH4 changes may be significantly affected by the assumed approximations. Depending on the investigated stratospheric region and the considered period, the error in estimated mean age of air trends can be large, especially in the lower stratosphere. For particular periods, the errors from the two approximations can lead to opposite effects, which may even cancel out. Finally, for a more reliable estimate of the mean age of air trends, we propose adjusting the approximation method by using an idealized age spectrum to propagate stratospheric entry mixing ratios. The findings of this work can be used for assessing the uncertainties in stratospheric BDC trend estimation from global satellite measurements.

Diagnosis of Atherosclerotic Plaques Using Vascular Endothelial Growth Factor Receptor-2 Targeting Antibody Nano-microbubble as Ultrasound Contrast Agent.

The atherosclerotic plaque is characterized by narrowing of blood vessels and reduced blood flow leading to the insufficient blood supply to the brain. The hemodynamic changes caused by arterial stenosis increase the shearing force of the fibrous cap on the surface of the plaque, thereby reducing the stability of the plaque. Unstable plaques are more likely to promote angiogenesis and increase the risk of patients with cerebrovascular diseases. A timely understanding of the formation and stability of the arterial plaque can guide in taking targeted measures for reducing the risk of acute stroke in patients. It has been confirmed that nano-microbubbles can enter these plaques through the gaps in the patient's vascular endothelial cells, thereby enhancing the acquisition of ultrasound information for plaque visualization. Therefore, we aim to investigate the diagnostic value of targeted nano-microbubbles for atherosclerotic plaques. This study constructed vascular endothelial growth factor receptor-2 (VEGFR-2) targeting antibody nano-microbubbles and compared its diagnostic value with that of blank nano-microbubbles for atherosclerotic plaques. Studies have found that VEGFR-2 targeting antibody nano-microbubbles can accurately detect the position of plaques. Its detection rate, sensitivity, and specificity for plaques are higher than those of blank nano-microbubbles. Similarly, the peak intensity and average transit time of VEGFR-2 targeting antibody nano-microbubbles were greater than those of blank nano-microbubbles. Therefore, we believe that the combination of VEGFR-2 antibody and nano-microbubbles can enhance the acquisition of ultrasound information on atherosclerotic plaque neovascularization, thereby improving the early diagnosis of unstable plaque.

Effect of Time and Temperature on SARS-CoV-2 in Municipal Wastewater Conveyance Systems

Wastewater surveillance for SARS-CoV-2 is becoming a widespread public health metric, but little is known about pre-analytical influences on these measurements. We examined SARS-CoV-2 loads from two sewer service areas with different travel times that were within the same metropolitan area. Throughout the one-year study, case rates were nearly identical between the two service areas allowing us to compare differences in empirical concentrations relative to conveyance system characteristics and wastewater treatment plant parameters. We found time did not have a significant effect on degradation of SARS-CoV-2 when using average transit times (22 vs. 7.5 h) (p = 0.08), or under low flow conditions when transit times are greater (p = 0.14). Flow increased rather than decreased SARS-CoV-2 case-adjusted concentrations, but this increase was only significant in one service area. Warmer temperatures (16.8–19.8 °C) compared with colder (8.4–12.3 °C) reduced SARS-CoV-2 case-adjusted loads by ~50% in both plants (p < 0.05). Decreased concentrations in warmer temperatures may be an important factor to consider when comparing seasonal dynamics. Oxygen demand and suspended solids had no significant effect on SARS-CoV-2 case-adjusted loads overall. Understanding wastewater conveyance system influences prior to sample collection will improve comparisons of regional or national data for SARS-CoV-2 community infections.

Effects of Early Acupuncture Combined with Rehabilitation Training on Limb Function and Nerve Injury Rehabilitation in Elderly Patients with Stroke: Based on a Retrospective Cohort Study

Objective A case-control study was conducted to explore the effect of acupuncture combined with rehabilitation training on limb function and nerve injury rehabilitation in elderly patients with stroke. Methods A total of 72 elderly patients with stroke treated from March 2019 to June 2021 in our hospital were enrolled as the object of study. The clinical data were collected and divided into two groups according to their different treatment methods. The patients cured with routine treatment combined with rehabilitation training were taken as the control group and the patients cured with acupuncture combined with rehabilitation training as the study group. The clinical efficacy was recorded, and the cognition and activities of daily living were evaluated by Terrell Cognitive Assessment scale, limb motor function score, and activities of daily living scale. The National Institutes of Health Stroke Scale (NIHSS) and Glasgow Coma Scale (GCS) were employed to compare the neurological function before and after treatment. Glasgow Outcome Scale (GOS) and Disability Rating Scale (DRS) were adopted to evaluate the functional prognosis. The simplified Fugl-Meyer assessment of motor recovery score was employed to evaluate the limb function of the patients. The Wolf Motor Function Test (WMFT) score was adopted to evaluate the functional rehabilitation effect of the patients. Enzyme-linked immunosorbent assay (ELISA) was adopted to determine the serum neurological function indexes such as nerve growth factor, Smur100B protein, and glial fibrillary acidic protein. The cerebral blood flow (CBF), peak time, average transit time, and cerebral blood volume were measured by CT perfusion imaging, and the incidence of side effects during treatment was recorded. Results Regarding the recovery of cognitive function and daily function after treatment, after treatment, the MoCA and ADL scores were increased, and the comparison indicated that the MoCA and ADL scores of the study group were remarkably higher compared to the control group (P < 0.05). With regard to the FMA-UE scores after treatment, the Fugl-Meyer scores were gradually increased, and the Fugl-Meyer scores in the study group were remarkably higher compared to the control group (P < 0.05) in the next two months. After 2 weeks, 4 weeks, 6 weeks, and 6 weeks of treatment, the WMFT scores gradually increased, and the WMFT score of the study group was remarkably higher compared to the control group. After treatment, the levels of nerve growth factor and S-100B protein were decreased, and the level of glial fibrillary acidic protein was increased. Comparison between the two groups, it indicated the improvement degree of each neurological function index in the study group was remarkably better (P < 0.05). With regard to cerebral hemodynamic indexes after treatment, 1 week after treatment, the CBF and average transit time of the observation group were remarkably higher compared to the control group, and the levels of cerebral blood volume and peak time were remarkably lower compared to the control group (P < 0.05). After 4 weeks of treatment, the cerebral hemodynamic indexes of the observation group did not change remarkably, and they were all lower than 1 week after the treatment. In the terms of side effects, 1 case of limb dysfunction, 1 case of swallowing dysfunction, 1 case of electrolyte disturbance, and none of infection in the study group, the incidence of adverse reactions was 8.33%. In the control group, there were 3 cases of limb dysfunction, 2 cases of swallowing dysfunction, 2 cases of electrolyte disturbance, and 3 cases of infection, and the incidence of adverse reactions was 27.78%. Compared between groups, the incidence of adverse reactions in the study group was lower (P < 0.05). Conclusion Early use of acupuncture combined with rehabilitation training has a remarkable therapeutic effect on elderly stroke patients. It can remarkably promote the recovery of the patient's condition, remarkably enhance their neurological function, cognitive function, motor function, and daily life function, and effectively strengthen the patient's prognosis score. It has important clinical application value to reduce the incidence of adverse reactions.