Reliability of urban microclimate simulations: spatio-temporal validation through intra-urban canyon transects for outdoor thermal comfort analysis.

Mitigating Urban Heat Island (UHI) intensity in cities through adaptative strategies has become an urgent need, as UHI are also exacerbated by climate change impacts imputable to anthropogenic actions. This study addresses the need for reliable simulation models to analyze outdoor thermal comfort (OTC) in future or alternative scenarios. The aim of the present study is to contribute to the validation of CFD urban microclimate simulations by employing intra-urban canyon transects as an alternative or a complementary approach to fixed stations. To accomplish this, we developed a cost-effective monitoring unit to carry out transects on a pre-defined route (1), devised the area of interest (2), elaborated a simulation model in ENVI-met (3), and proposed different validation methods for comparative analyses (4). Results indicate that temporal validated simulation tended to underestimate thermal indices in the morning and night and overestimate them in the afternoon, while spatio-temporal validation under a human-centric comfort approach via wearable sensing notably improved accuracy. Moderate to very strong agreement between simulation and measurement data in summer (Willmot's d ~ 0.70, d ~ 0.81) and very strong agreement in winter (d ~ 0.79, d ~ 0.96), with low error magnitudes in summer (RMSE ~ 0.91℃ and 9.59%, MBE ~ 0.23℃ and 9.10%) have been found. In winter, such figures were RMSE ~ 0.71℃ and 3.51%, MBE ~ 0.00℃ and 0.98%, for the spatio-temporal validated model. This research contributes to enhancing the reliability of relatively affordable CFD urban microclimate simulations, supporting its scale up for policymakers in implementing effective strategies for OTC.

Subtle morpho-functional kidney changes in type-2 diabetes mellitus patients: A duplex ultrasound assessment.

Objectives: Diabetes mellitus (DM) is a common endocrine disease with serious effects on multiple organs including the kidneys. This study aimed to investigate the subtle effects of type 2 DM (T2DM) on the kidneys. Methods: This was a prospective case-control study conducted in the Radiology Department of University of Science and Technology Hospital (USTH) campus, Sana'a, Republic of Yemen, from 1 January 2020 to 31 November 2020. The renal length (RL), renal width (RW), resistive index (RI), and pulsatility index (PI) were prospectively measured in patients with T2DM and healthy controls. The results were compared using the independent samples t-test. Comparisons were likewise performed between patients with controlled DM and patients with uncontrolled DM. Results: A total of hundred individuals, 50 diabetic patients and 50 controls, were enrolled in this study. Their mean age was 54 ± 7.88 years (range: 40-75 years). The RL, RI, and PI of both kidneys were significantly higher in T2DM than in the control group. Moreover, the RL, RI, PI and creatinine were slightly higher in patients with uncontrolled than in those with controlled DM. Conclusion: T2DM has significant accentuating effects on the RL, RI and PI associated with low effective renal plasma flow, even before acute kidney injury or chronic kidney disease diagnosis, which may be attenuated by careful regulation of DM. Ultrasound Doppler is a highly valuable imaging modality for evaluating the subtle effects of T2DM on kidney dimensions and blood flow. The RI can be implemented as a tool for the early diagnosis of kidney disease and contribute to slowing the disease progression and preventing renal failure.

A needle-type micro-sampling device for collecting nanoliter sap sample from plants.

In plant research, measuring the physiological parameters of plants is vital for understanding the behavior and response of plants to changes in the external environment. Plant sap analysis provides an approach for elucidating the physiological condition of plants. However, to facilitate accurate sap analysis, a sampling device capable of collecting sap samples from plants is required. In this paper, a minimally invasive, needle-type micro-sampling device capable of collecting nanoliter (~ 91 nL) quantities of sap from plants is described. The developed micro-sampling system showed great reproducibility (3%) in experiments designed to assess sampling performance. As a proof of concept, sap samples were collected continuously from target plants with the micro-sampling system, and the dynamic changes in potassium ions, plant hormones and sugar levels inside plants were analyzed. The results demonstrated the feasibility of the micro-sampling device and its potential for developing a measurement system for plant research in the future.

The Effects of Different Fluorescent Indicators in Observing the Changes of the Mitochondrial Membrane Potential during Oxidative Stress-Induced Mitochondrial Injury of Cardiac H9c2 Cells.

We evaluated the ability of different fluorescent indicators by various analytical instruments, including a laser scanning confocal microscope (LSCM), fluorescence plate reader, and flow cytometer (FCM), to measure the mitochondrial membrane potential (ΔΨm) of cardiac H9c2 cells during oxidative stress-induced mitochondrial injury. The mitochondrial oxygen consumption rate and a transmission electron microscope were used to detect changes in mitochondrial functions and morphology, respectively. Cardiac H9c2 cells were exposed to H2O2 (500, 750, 1000, and 1250 µM) to induce mitochondrial oxidative stress injury, and fluorescent indicators including tetramethyl rhodamine ethyl ester (TMRE), 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1), and rhodamine 123 (R123) were used to detect changes in ΔΨm using an LSCM, fluorescence plate reader, and FCM. The decrease in ΔΨm caused by H2O2 was determined by endpoint and dynamic analyses after staining with JC-1 or TMRE. With the R123 probe, the LSCM could only detect the change in ΔΨm caused by 1000 µM H2O2. Moreover, R123 was less effective than JC-1 and TMRE for measurement of ΔΨm by the LSCM. Our data indicated that an LSCM is the most suitable instrument to detect dynamic changes in ΔΨm, whereas all three instruments can detect ΔΨm at the endpoint.

Fluorescence imaging-based methods for single-cell protein analysis.

The quantity and activity of proteins in many biological systems exhibit prominent heterogeneities. Single-cell analytical methods can resolve subpopulations and dissect their unique signatures from heterogeneous samples, enabling a clarifying view of the biological process. Over the last 5 years, technologies for single-cell protein analysis have significantly advanced. In this article, we highlight a branch of those technology developments involving fluorescence-based approaches, with a focus on the methods that increase the ability to multiplex and enable dynamic measurements. We also analyze the limitations of these techniques and discuss current challenges in the field, with the hope that more transformative platforms can soon emerge.

Measurements of Dynamic Deformations of Building Structures by Applying Wire Sensors.

Measurements of deformations by means of vibrating wire sensors are very important in the monitoring of building structures. These types of sensors are characterized by a high resistance to environmental conditions, long time of measurement stability, and a possibility to use long electric cables with a solid encasement in concrete. Vibrating wire sensors are mainly used for measuring stable or slowly changing deformations, however applications of these sensors for measuring time-variable deformations are becoming popular. New solutions generate new problems, which in case of vibrating wire sensors are mainly related to the operational stability of the systems exciting wire vibrations. The structure of such sensors and the length of the electric cables, which can reach a few kilometers, have an essential influence on their operations. This paper undertakes the task of determining the influence of the electric cables length on the proper operation of the measurement system and provides advice for improvements of its measurement possibilities. The subject of investigation constitutes a measurement system based on a self-exciting impulse exciter, for which the impedance of the electric cables and of the vibrating wire sensor are the most essential parameters. A mathematical model of this system, experimental verification of the model, and the results of theoretical analyses and measurement tests for electric cables of various lengths are presented in this paper.

Dynamic Measurements Using FDM 3D-Printed Embedded Strain Sensors.

3D-printing technology is opening up new possibilities for the co-printing of sensory elements. While quasi-static research has shown promise, the dynamic performance has yet to be researched. This study researched smart 3D structures with embedded and printed sensory elements. The embedded strain sensor was based on the conductive PLA (Polylactic Acid) material. The research was focused on dynamic measurements of the strain and considered the theoretical background of the piezoresistivity of conductive PLA materials, the temperature effects, the nonlinearities, the dynamic range, the electromagnetic sensitivity and the frequency range. A quasi-static calibration used in the dynamic measurements was proposed. It was shown that the temperature effects were negligible, the sensory element was linear as long as the structure had a linear response, the dynamic range started at ∼ 30 µ ϵ and broadband performance was in the range of few kHz (depending on the size of the printed sensor). The promising results support future applications of smart 3D-printed systems with embedded sensory elements being used for dynamic measurements in areas where currently piezo-crystal-based sensors are used.

Influences of different lower cervical bone graft heights on the size of the intervertebral foramen: multiple planar dynamic measurements with laser scanning.

The aim of this study is to evaluate the influences of different bone graft heights on the size of the intervertebral foramen, which will help determine the optimal graft height in clinical practice. Six fresh adult cadavers were used, with the C5-C6 vertebral column segment defined as the functional spinal unit (FSU). After discectomy, the C5/6 intervertebral height was set as the baseline height (normal disc height). We initially used spiral computed tomography (CT) to scan and measure the middle area of the intervertebral foramen when at the baseline height. Data regarding the spatial relationship of C5-C6 were subsequently collected with a laser scanner. Grafting with four different sized grafts, namely, grafts of 100, 130, 160, and 190% of the baseline height, was implanted. Moreover, we scanned to display the FSU in the four different states using Geomagic8.0 studio software. Multiple planar dynamic measurements (MPDM) were adopted to measure the intervertebral foramen volume, middle area, and areas of internal and external opening. MPDM with a laser scanner precisely measured the middle area of the intervertebral foramen as spiral CT, and it is easy to simulate the different grafts implanted. With the increase of the bone graft height, the size of the intervertebral foramen began to decrease after it increased to a certain point, when grafts of 160% of the baseline height implanted. MPDM of the intervertebral foramens with laser scanning three-dimensional (3D) reconstitution are relatively objective and accurate. The recommended optimal graft height of cervical spondylosis is 160% of the mean height of adjacent normal intervertebral spaces.

Measuring Dynamic Signals with Direct Sensor-to-Microcontroller Interfaces Applied to a Magnetoresistive Sensor.

This paper evaluates the performance of direct interface circuits (DIC), where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account both the desired resolution and the bandwidth of the input signal. Such an analysis reveals that there is a trade-off between the sampling frequency and the resolution of the measurement, and this depends on the selected value of the capacitor that forms the RC circuit together with the sensor resistance. This performance is then experimentally proved with a DIC measuring a magnetoresistive sensor exposed to a magnetic field of different frequencies, amplitudes, and waveforms. A sinusoidal magnetic field up to 1 kHz can be monitored with a resolution of eight bits and a sampling frequency of around 10 kSa/s. If a higher resolution is desired, the sampling frequency has to be lower, thus limiting the bandwidth of the dynamic signal under measurement. The DIC is also applied to measure an electrocardiogram-type signal and its QRS complex is well identified, which enables the estimation, for instance, of the heart rate.

Fast Interrogation of Fiber Bragg Gratings with Electro-Optical Dual Optical Frequency Combs.

Optical frequency combs (OFC) generated by electro-optic modulation of continuous-wave lasers provide broadband coherent sources with high power per line and independent control of line spacing and the number of lines. In addition to their application in spectroscopy, they offer flexible and optimized sources for the interrogation of other sensors based on wavelength change or wavelength filtering, such as fiber Bragg grating (FBG) sensors. In this paper, a dual-OFC FBG interrogation system based on a single laser and two optical-phase modulators is presented. This architecture allows for the configuration of multimode optical source parameters such as the number of modes and their position within the reflected spectrum of the FBG. A direct read-out is obtained by mapping the optical spectrum onto the radio-frequency spectrum output of the dual-comb. This interrogation scheme is proposed for measuring fast phenomena such as vibrations and ultrasounds. Results are presented for dual-comb operation under optimized control. The optical modes are mapped onto detectable tones that are multiples of 0.5 MHz around a center radiofrequency tone (40 MHz). Measurements of ultrasounds (40 kHz and 120 kHz) are demonstrated with this sensing system. Ultrasounds induce dynamic strain onto the fiber, which generates changes in the reflected Bragg wavelength and, hence, modulates the amplitude of the OFC modes within the reflected spectrum. The amplitude modulation of two counterphase tones is detected to obtain a differential measurement proportional to the ultrasound signal.