Measurement Method Research Articles

Natural gas pipeline leak diagnosis based on manifold learning

Natural gas pipeline leakage is a common safety hazard, which can have a great impact on the economy and the environment. This paper proposed a novel manifold learning-enabled feature extraction method for natural gas pipeline leakage diagnosis. Firstly, the natural gas pipeline working condition signal is decomposed and denoised by Variational mode decomposition (VMD). Secondly, the denoised pipeline signals were constructed into a form expressed by the Symmetric positive definite matrix (SPD) using the VMD reconstruction technique, and the geodesic distance measurement method was applied to the SPD matrix to make the data located on the SPD manifold. Then feature extraction is carried out by Local linear embedding (LLE) method based on asymmetric distance. Finally, pattern recognition of the features extracted in this paper by Support vector machine (SVM) can achieve 100% recognition accuracy. By enabling faster and more accurate leak detection, the method minimizes gas loss, as well as mitigating the environmental risks caused by this potent greenhouse gas.

Harmonic voltage measurement based on capacitive equipment dielectric equivalent model and responding current

Abstract With the increasing proportion of new energy and the power electronic equipment in the power grid, accurate measurement of harmonic voltage has become increasingly important for power quality monitoring. In order to solve the problem of high-precision measurement of harmonic voltage in the power grid, this manuscript proposes a high-precision harmonic voltage measurement method based on the dielectric equivalent model (DEM) of capacitive equipment and its responding current. Based on DEM, a voltage-current transfer function of the capacitive device is established, and harmonic voltage is reconstructed with the responding current. Considering the dielectric relaxation characteristics of capacitive device other than a pure capacitor model, this manuscript analyzes the fitting performance of different equivalent capacitance models and improves the traditional pure capacitance model to a more suitable DEM for harmonic voltage reconstruction. The DEM parameters of capacitive devices are obtained through the frequency domain spectroscopy (FDS) and intelligent parameter identification algorithms, which improved the measurement accuracy of harmonic voltage and reduced computational complexity. The harmonic voltage testing platform is established to test the simulated high-voltage harmonics and the harmonic voltage of the actual grid voltage. The results show that the proposed harmonic voltage measurement method can meet the high-precision reconstruction of harmonic voltage in the frequency range of 50~2500Hz, and the system testing error with sensors is less than 2%. The testing accuracy is higher than traditional voltage transformers and testing systems based on pure capacitance models.

Research on plunging resistant force of drive shaft systems based on fractal methods

When drive shaft systems move axially, the friction between rollers and raceways inside tripod joints will generate a plunging resistant force (PRF). Excessive PRF causes significant noise in vehicles. To reveal the generation mechanism, an analytical model of the PRF is proposed by analyzing the axial motion mechanism of a drive shaft system. Based on the analytical model and fractal methods, a fractal model of the PRF is proposed to reveal influencing factors of the PRF more comprehensively. An effective method for correcting distribution of asperities between rollers and raceways is proposed to describe the contact state accurately. The fractal model shows that influencing factors of the PRF include the fractal dimension and the characteristic scale coefficient related to the roughness of contact surfaces, the material parameters, the working angle, and the correction coefficient for distribution of asperities. A measurement method for the PRF is subsequently proposed, as well as the fractal dimension and the characteristic scale coefficient are measured and determined. The effectiveness of the fractal model is verified based on the measurement of the PRF and the determined fractal dimension and characteristic scale coefficient. Numerical analysis results show that reducing the Poisson's ratio, the yield strength and the working angle, increasing the characteristic scale coefficient, the elastic modulus and the correction coefficient, and selecting a fractal dimension lower than 1.544 or higher than 1.782 can effectively reduce the PRF, thereby reducing the noise caused by the PRF.

Error analysis for determining transverse tensile delamination strength of REBCO coated conductors by anvil test: numerical simulation demonstrations

Abstract RE-Ba-Cu-O (REBCO, where RE = Y, Gd, Sm, and other rare earth elements) coated conductor (CC) tapes exhibit considerable potential for application within the domains of high-energy physics and high-field science. Nevertheless, weak interfacial properties pose a significant obstacle, impeding the progress and practical implementation in high-field scenarios. The anvil tension method has been extensively employed for the assessment of transverse delamination strength of REBCO CC tapes. However, the outcomes derived from anvil tension exhibit severe dispersion, thereby impeding its efficacy in evaluating material performance. The underlying cause of this phenomenon remains unidentified. In this study, error analysis of anvil measurement method in determining the transverse tensile delamination strength (TTDS) of REBCO CC tapes was conducted based on finite element (FE) numerical simulations. A two-dimensional multilayer elastic-plastic delamination FE model with main layers of REBCO CC tapes, solder connecting layers and anvil materials were developed based on the bilinear cohesive zone model. The effects of anvil test conditions and the structural configuration of the conductor itself on the test results were discussed. Simulation results show that localized premature cracking of the interface due to stress concentration and plastic yielding of the CC tape around the loading boundary is the root reason for the discrepancy between the anvil test results and the true interfacial strength. Therefore, anvil test conditions (including top anvil dimensions, soldering conditions, loading eccentricity angle, and anvil material properties) as well as the structural configuration of the conductor itself (including edge initial crack length, edge encapsulation width, and stabilizer thickness) have a significant impact on anvil test-based TTDS results.

266 nm Laser-Induced Fluorescence Reference Spectra of Ketones and Aromatic Compounds

ABSTRACT Laser-induced fluorescence (LIF) is an established noninvasive measurement method to determine temperature distributions and local gas concentrations in combustion processes with high spatial and temporal resolution. This work presents high-precision LIF spectra of acetone and other tracers at ambient conditions. By using a large UV-sensitive sCMOS camera instead of an image intensified camera, many issues like nonlinearity, varying sensitivity, vignetting, limited resolution etc. could be minimized or eliminated. Particular care was taken to remove residual stray light and to calibrate the spectra with metrological traceability to the International System of Units SI.

Unshielded facility testbed for electromagnetic wave attenuation using absorber slabs

AbstractThis paper presents a testbed for unshielded facilities utilizing planar electromagnetic absorbers. These slabs demonstrate comparable shielding effectiveness to that of reinforced concrete in the frequency range from 1 GHz to 6 GHz. The testbed serves as a platform for developing a measurement method to assess unshielded facilities. It can be configured with different materials that have various levels of shielding effectiveness. We evaluate the shielding effectiveness of the absorber slab and extract its electromagnetic parameters. The testbed is implemented in a semi‐anechoic chamber with inner dimensions of 3.00 × 3.06 × 2.50 m3. The electromagnetic wave attenuation for the unshielded facilities is defined as the ratio of received power within the assessment space relative to the incident power. The measurement results provide quantitative information on the attenuation of electromagnetic waves within unshielded facilities. The testbed configured with two types of incident planes is evaluated and compared with the mean attenuation and distribution characteristics.

Innovating Thiopurine Therapeutic Drug Monitoring: A Systematic Review and Meta-Analysis on DNA-Thioguanine Nucleotides (DNA-TG) as an Inclusive Biomarker in Thiopurine Therapy.

Thioguanine (TG), azathioprine (AZA), and mercaptopurine (MP) are thiopurine prodrugs commonly used to treat diseases, such as leukemia and inflammatory bowel disease (IBD). 6-thioguanine nucleotides (6-TGNs) have been commonly used for monitoring treatment. High levels of 6-TGNs in red blood cells (RBCs) have been associated with leukopenia, the cutoff levels that predict this side effect remain uncertain. Thiopurines are metabolized and incorporated into leukocyte DNA. Measuring levels of DNA-incorporated thioguanine (DNA-TG) may be a more suitable method for predicting clinical response and toxicities such as leukopenia. Unfortunately, most methodologies to assay 6-TGNs are unable to identify the impact of NUDT15 variants, effecting mostly ethnic populations (e.g., Chinese, Indian, Malay, Japanese, and Hispanics). DNA-TG tackles this problem by directly measuring thioguanine in the DNA, which can be influenced by both TPMT and NUDT15 variants. While RBC 6-TGN concentrations have traditionally been used to optimize thiopurine therapy due to their ease and affordability of measurement, recent developments in liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques have made measuring DNA-TG concentrations in lymphocytes accurate, reproducible, and affordable. The objective of this systematic review was to assess the current evidence of DNA-TG levels as marker for thiopurine therapy, especially with regards to NUDT15 variants. A systematic review and meta-analysis were performed on the current evidence for DNA-TG as a marker for monitoring thiopurine therapy, including methods for measurement and the illustrative relationship between DNA-TG and various gene variants (such as TPMT, NUDT15, ITPA, NT5C2, and MRP4). PubMed and Embase were systematically searched up to April 2024 for published studies, using the keyword "DNA-TG" with MeSH terms and synonyms. The electronic search strategy was augmented by a manual examination of references cited in articles, recent reviews, editorials, and meta-analyses. A meta-analysis was performed using R studio 4.1.3. to investigate the difference between the coefficients (Fisher's z-transformed correlation coefficient) of DNA-TG and 6-TGNs levels. A meta-analysis was performed using RevMan version 5.4 to investigate the difference in DNA-TG levels between patients with or without leukopenia using randomized effect size model. The risk of bias was assessed using the Newcastle-Ottowa quality assessment scale. In this systematic review, 21 studies were included that measured DNA-TG levels in white blood cells for either patients with ALL (n = 16) or IBD (n = 5). In our meta-analysis, the overall mean difference between patients with leukopenia (ALL + IBD) versus no leukopenia was 134.15 fmol TG/µg DNA [95% confidence interval (CI) (83.78-184.35), P < 0.00001; heterogeneity chi squared of 5.62, I2 of 47%]. There was a significant difference in DNA-TG levels for patients with IBD with and without leukopenia [161.76 fmol TG/µg DNA; 95% CI (126.23-197.29), P < 0.00001; heterogeneity chi squared of 0.20, I2 of 0%]. No significant difference was found in DNA-TG level between patients with ALL with or without leukopenia (57.71 fmol TG/µg DNA [95% CI (-22.93 to 138.35), P < 0.80]). DNA-TG monitoring was found to be a promising method for predicting relapse rates in patients with ALL, and DNA-TG levels are likely a better predictor for leukopenia in patients with IBD than RBC 6-TGNs levels. DNA-TG levels have been shown to correlate with various gene variants (TPMT, NUDT15, ITPA, and MRP4) in various studies, points to its potential as a more informative marker for guiding thiopurine therapy across diverse genetic backgrounds. This systematic review strongly supports the further investigation of DNA-TG as a marker for monitoring thiopurine therapy. Its correlation with treatment outcomes, such as relapse-free survival in ALL and the risk of leukopenia in IBD, underscores its role in enhancing personalized treatment approaches. DNA-TG effectively identifies NUDT15 variants and predicts late leukopenia in patients with IBD, regardless of their NUDT15 variant status. The recommended threshold for late leukopenia prediction in patients with IBD with DNA-TG is suggested to be between 320 and 340 fmol/µg DNA. More clinical research on DNA-TG implementation is mandatory to improve patient care and to improve inclusivity in thiopurine treatment.

Bioinformatics comparison of hemolysin in different bacteria and experimental evaluation of anti-cancer properties of extracts of some hemolysin-producing bacteria

Cancer is one of the main causes of death in the world. Resistance to anticancer treatments in patients with advanced solid tumors leads to new treatments. Therefore, more alternative anticancer methods have been found over time with greater specificity against tumor cells and with less or no adverse effects on normal cells. Bacterial spores of obligate anaerobes exclusively germinate in the hypoxic/necrotic areas and not in the well oxygenated areas of the body. This unique phenomenon has been exploited in using bacterial spores as a remedy for cancer. Bacterial toxins also play a significant role in either directly killing tumor cells or altering the cellular processes of the tumor cells which ultimately leads to the inhibition and regression of the solid tumor. In the microbial environment, pathogens such as Staphylococcus aureus, Bacillus cereus, or Streptococcus pyogenes produce hemolysin. This protein is used as an anti-cancer protein. To identify the production of hemolysin by bacteria, which can destroy cancer cells more effectively, different bacterial strains were first cultured in blood agar culture medium. The Strains that completely lysed red blood cells, creating transparent zones, were selected for further investigation. Then, to find out which strains have more ability to lyse red blood cells, the qualitative method of halo diameter measurement was used. Also, using quantitative methods, hemolysin strength in microtubes was determined compared to control samples. The results of the hemolysis in the microtube and the qualitative test results showed similar results. In the next step, the cell viability test was performed with the partially purified proteins. Then, bioinformatics studies such as secondary structure investigation, physicochemical properties, pseudo amino acid composition, and molecular docking were performed. The results of molecular docking showed that the hemolysin protein has the highest affinity for the cholesterol of the cytoplasmic membrane, respectively, of Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus bacteria which play a significant role in either directly killing tumor cells or altering the cellular processes of the tumor cells which ultimately leads to the inhibition and regression of the solid tumor.

Cell-Resolved PV Soiling Measurement Using Drone Images

The maintenance of photovoltaic (PV) power plants is of central importance for their yield. To reach higher efficiencies in PV parks, it is helpful to detect soiling such as dust deposition and to apply this information to optimize cleaning strategies. Furthermore, a periodic inspection of the PV modules with infrared (IR) imagery is of advantage to detect and potentially remove faulty PV modules. Soiling can be erroneously interpreted as PV module defects and hence spatially resolved soiling measurements can improve the results of IR-based PV inspection. So far, soiling measurements are mostly performed only locally in PV fields, thus not supporting the above-mentioned IR inspections. This study presents a method for measuring the soiling of PV modules at cell resolution using RGB images taken by aerial drones under sunny conditions. The increase in brightness observed for soiled cells under evaluation, compared to clean cells, is used to calculate the transmission loss of the soiling layer. Photos of a clean PV module and a soiled module for which the soiling loss is measured electrically are used to determine the relation between the brightness increase and the soiling loss. To achieve this, the irradiance at the time of the image acquisitions and the viewing geometry are considered. The measurement method has been validated with electrical measurements of the soiling loss yielding root mean square deviations in the 1% absolute range. The method has the potential to be applied to entire PV parks in the future.

Single Entity Electrocatalysis.

Making a measurement over millions of nanoparticles or exposed crystal facets seldom reports on reactivity of a single nanoparticle or facet, which may depart drastically from ensemble measurements. Within the past 30 years, science has moved toward studying the reactivity of single atoms, molecules, and nanoparticles, one at a time. This shift has been fueled by the realization that everything changes at the nanoscale, especially important industrially relevant properties like those important to electrocatalysis. Studying single nanoscale entities, however, is not trivial and has required the development of new measurement tools. This review explores a tale of the clever use of old and new measurement tools to study electrocatalysis at the single entity level. We explore in detail the complex interrelationship between measurement method, electrocatalytic material, and reaction of interest (e.g., carbon dioxide reduction, oxygen reduction, hydrazine oxidation, etc.). We end with our perspective on the future of single entity electrocatalysis with a key focus on what types of measurements present the greatest opportunity for fundamental discovery.

A digital volume pulse device-finger photo pulse plethysmography to trace the vascular integrity amongst the low back pain subjects with lumbar disc degenerative diseases diagnosed by MRI analysis.

Finger photo pulse plethysmography is a simple, inexpensive and non-invasive method for measurement of arterial stiffness. The objective is to assess the correlation of arterial stiffness in low back pain subjects with lumbar disc degeneration. Thirty-four back pain patients of both sexes in age group of 30-65 were included. Anthropometric measures like height, body weight, body mass index (BMI) were included. Stiffness index (SI) and reflection index (RI) were measured from the digital volume pulse waveform. There was a negative correlation between SI/RI and no correlation between SI and RI with BMI in both sexes. A significant correlation found between weight and BMI in both sexes. Arterial stiffness may not have any influence on disc degeneration. BMI showed some influence on disc degeneration and back pain.

Microfluidic Rheology: An Innovative Method for Viscosity Measurement of Gels and Various Pharmaceuticals

Measuring the viscosity of pharmaceutical dosage forms is a crucial process. Viscosity provides information about the stability of the composition, the release rate of the drug, bioavailability, and, in the case of injectable drug formulations, even the force required for injection. However, measuring viscosity is a complex task with numerous challenges, especially for non-Newtonian materials, which include most pharmaceutical formulations, such as gels. Selecting the appropriate shear rate is critical. Since viscosity in many systems is highly temperature-dependent, stable temperature control is necessary during the measurement. Using microfluidics technology, it is now possible to perform rheological characterization and conduct fast and accurate measurements. Small sample volumes (even below 500 µL) are required, and viscosity determination can be carried out over a wide range of shear rates. Nevertheless, the pharmaceutical application of viscometers operating on the principle of microfluidics is not yet widespread. In our work, we compare the results of measurements taken with a microfluidic chip-based viscometer on different pharmaceutical forms (gels, solution) with those obtained using a traditional rotational viscometer, evaluating the relative advantages and disadvantages of the different methods. The microfluidics-based method enables time- and sample-efficient viscosity analysis of the examined pharmaceutical forms.

Using unsupervised learning based convolutional neural networks to solve Digital Image Correlation

Digital Image Correlation (DIC) is a robust, non-contact method for full-field deformation measurement widely used in photomechanics. Based on subset image matching and an iterative optimization architecture, traditional DIC deformation field analysis requires manual selection of such calculation parameters as subset size, rendering it challenging to balance spatial resolution and measurement resolution in non-uniform field measurements. The requirement of manual parameter adjustment is lowered by a recently emerged supervised learning-based neural network DIC method, as it establishes a direct correlation between images and deformation fields using deep neural networks (DNN). However, its generalization and accuracy are contingent on the scope and variety of the dataset because it requires training with a large number of simulated speckle images of deformation fields with known standards. This paper proposes an unsupervised learning neural network based DIC measurement method that circumvents the need for standard deformation fields and achieves high precision analysis of deformed fields. It constructs a loss function based on the photometric consistency assumption of speckle images before and after deformation and allows the neural network model to directly extract displacement information from the gray data of the “reference image-deformed image” pair. Meanwhile, the model is enhanced accordingly by further introducing displacement continuity constraints to enhance accuracy and mitigate noise interference. Validation through both simulated and real experiments shows that the proposed approach surpasses traditional subset DIC in measuring non-uniform deformation fields with higher precision. It also offers superior flexibility and adaptability over supervised learning-based neural network DIC methods by eliminating the need for a large training dataset, allowing for immediate application in displacement field analysis.

Optimization of Ti2O3 thin films by magnetron sputtering and study of their photoelectric performance

AbstractAbstractIn this study, Ti2O3 thin films were successfully produced using magnetron sputtering. Through orthogonal gradient experiments, the impact of substrate temperature, sputtering vacuum, RF power, and sputtering duration on surface morphology, roughness, physical structure, and resistivity was investigated. Various analytical techniques were employed, including AFM and SEM for surface morphology observation, XRD and Raman for qualitative physical structure analysis, XPS for elemental valence examination, and the four‐probe method for resistivity measurements. The study identified optimal growth conditions for Ti2O3 films, demonstrating a low resistivity of 2.66 × 10−3 Ω cm under the following conditions: RF power of 200 W, sputtering vacuum of .6 Pa, substrate temperature of 600°C, and sputtering duration of 60 min. Additionally, the sensor arrays were efficiently fabricated using the Lift‐off method to evaluate the photoelectric performance of the films. A light responsiveness of approximately 6 µA/W was observed in the device when illuminated with 950 nm light for 10 s. This finding carries important implications for the use of Ti2O3 thin films in future photoelectric devices.

Corrective Evaluation of Response Capabilities of Flexible Demand-Side Resources Considering Communication Delay in Smart Grids

With the gradual increase in the proportion of new energy sources in the power grid, there is an urgent need for more flexible resources to participate in short-term regulation. The impact of communication network channel quality will continue to magnify, and factors such as communication latency may directly affect the efficiency and effectiveness of resource regulation. In this context of a large number of flexible demand-side resources accessing the grid, this article proposes a bidirectional channel delay measurement method based on MQTT (Message Queuing Telemetry Transport). It can effectively evaluate the real-time performance of communication links, considering that resources mainly access the grid through the public network. Subsequently, focusing on two typical types of resources on the demand side, namely, split air conditioners and central air conditioners, this article proposes an assessment method for correcting the response capabilities of air conditioning resources considering communication latency. Experimental simulations are conducted, and the results demonstrate that under given communication conditions, this method can more accurately estimate the response capability of air conditioners. This provides a basis for formulating more reasonable scheduling strategies, avoiding excessive or insufficient resource regulation caused by communication issues, and aiding the power grid in achieving precise scheduling.

Validation of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the ISO 81060-2:2018/AMD 1:2020 protocol.

The aim of this study was to evaluate the accuracy of the DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor in the general population according to the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). The test monitor was used to measure SBP and DBP and pulse rate in the wrists using the oscillometric method. According to this protocol using the same-arm sequential blood pressure measurement method, subjects were recruited to fulfill the age, sex, blood pressure, and cuff distribution criteria of the Universal Standard. A single cuff for wrist sizes of 13.5-21.5 cm was used. A total of 85 subjects were included in this study. According to Criterion 1, the mean difference in SBP between the test device and the reference device was 0.89 mmHg, with a SD of 7.76 mmHg. The mean difference of DBP was -1.44 mmHg, with a SD of 6.23 mmHg. The mean difference between SBP and DBP was less than 5.0 mmHg, and the SD was less than 8.0 mmHg, which met the requirements. According to Criterion 2, the SD of the mean differences of SBP between the test device and the reference device per subject was 5.65 mmHg, which was less than 6.88 mmHg and met the requirements. The SD of the mean differences of DBP between the test device and the reference device per subject was 5.61 mmHg, which was less than 6.78 mmHg and met the requirements. The DBP-8278B Wrist-type Fully Automatic Blood Pressure Monitor met the requirements of the AAMI/ESH/ISO Universal Standard (ISO 81060-2 : 2018/AMD 1 : 2020). It can be recommended for home and clinical use.

Gap Measurement Method Based on Projection Lines and Convex Analysis of 3D Points Cloud

Abstract Accurate measurement of the gap between the lower surface of the relay and the ground is critical for ensuring the quality of the finished product. Traditional gap measurement methods have some shortcomings, such as low accuracy, poor robustness, and loss of depth clues in obscured areas. In this study, a novel gap measurement method based on computer vision is proposed, which includes a projection line model based on guided filtering and a 3D surface point cloud model based on a three dimensional plane reference.- The relay gap was measured by calculating the projection lines of the upper and lower surfaces of the gap with an error of ±0.016 mm. A 3D point cloud model captures the key features of the underside of the relay through image processing techniques, and combines convex hull and centroid estimation to construct a three-dimensional reference plane for the gap, which could achieve high-precision, real-time measurement of the gap (with an error less than ±0.0087 mm). The experimental measurement results show that the proposed method is better than the SelfConvNet method, which has a high measurement accuracy and strong anti-interference ability, and an accuracy rate of up to 99.5% in factory relay quality inspection experiments.&amp;#xD;

Pulsed-Mode Magnetic Field Measurements with a Single Stretched Wire System

In synchrotrons, accurate knowledge of the magnetic field generated by bending dipole magnets is essential to ensure beam stability. Measurement campaigns are necessary to characterize the field. The choice of the measurement method for such campaigns is determined by the combination of magnet dimensions and operating conditions and typically require a trade-off between accuracy and versatility. The single stretched wire (SSW) is a well-known, polyvalent method to measure the integral field of magnets having a wide range of geometries. It, however, requires steady-state excitation. This work presents a novel implementation of this method called pulsed SSW, which allows the system to measure rapidly time-varying magnetic fields, as is often needed, to save power or gain beam time. We first introduce the measurement principle of the pulsed SSW, followed by a combined strategy to calculate the absolute magnetic field by incorporating the classic DC SSW method. Using a bending magnet from the Proton Synchrotron Booster located at the European Organization for Nuclear Research as a case study, we validate the pulsed SSW method and compare its dynamic measurement capabilities to a fixed induction coil, showing thereby how the coil calibration must be adjusted according to the field level. Finally, we assess the method’s measurement accuracy using the standard SSW as a reference and present an analysis of the primary noise contributors.

Investigating spatiotemporal patterns and determinants of land resource misallocation in prefecture‐level China

AbstractThe misallocation of land resources is an important factor restricting the high‐quality development of China's economy. Based on the perspective of supply and demand matching, this study proposed a measurement method for the spatial misallocation of land resources and constructed two models for the testing and decomposition of factors affecting land resource spatial misallocation. We used this measurement method and these two models to explore the spatiotemporal characteristics and determinants of the spatial misallocation of land resources in China from 2000 to 2018 with the aim of providing policy recommendations for the correction of land resource misallocation in China and other developing countries. The results showed that the spatial misallocation of land resources in China showed an upward trend with evident spatial differentiation and the proportion of cities with high and severe misallocation increased. Industrial isomorphism and market misallocation are the main driving factors of land misallocation. Government misallocation and factor market abnormal development aggravate land resource misallocation. Extensive economic development and excessive factor agglomeration have a small effect on land resource spatial misallocation. Therefore, strengthening the land supply‐side reform, and implementing differentiated land allocation policies are effective pathways to control land resource misallocation in China.

Real world treatment of hypertension on hemodialyses-data from large Polish database.

The prevalence of hypertension among patients with end stage kidney disease (ESKD) undergoing hemodialysis (HD) ranges from 72-88% depending on applied diagnostic criteria and chosen method of blood pressure measurement. Despite the guidelines recommending the widespread use of renin angiotensin system blockers (RASB) in patients with kidney disease, their utilization in patients on HD may be suboptimal, especially in patients with preserved diuresis. This hesitance often steams from concern is often due to fear of a decrease in eGFR and a subsequent decrease in diuresis. The aim of this study was to compare clinical characteristics, blood pressure, safety, and hemodialysis adequacy indices in hypertensive HD patients on multiple antihypertensive drug regimens, including diuretic treated with RASB (RASB group) or without RASB (no-RASB) with preserved residual diuresis. We sought to examine the real life use of RASB in hemodialysis patients in relation to their clinical characteristics, blood pressure, safety, and hemodialysis adequacy. From a database of 5879 patients receiving hemodialysis (mean age 65.2±14.2 yrs., 60% of males) of the largest provider of HD in the country, we selected the subgroup treated with at least three antihypertensive medications including diuretics. We compared patients treated with RASB to counterparts without RASB (no-RASB). RASB group has similar age and gender proportions as well as BMI and bioimpedance,compared to counterparts. However, dry body mass was significantly lower in the RASB group (78.1±18.3 kg vs. 80.0±18.2 kg, p&lt;0.017). Prevalence of diabetes mellitus was similar in both groups, but RASB-treated patients have cardiovascular diseases more frequently (70.1% vs. 60.8%; p&lt;0.001). Systolic blood pressure and the number of antihypertensive drugs used were significantly higher in RASB patients than in counterparts (146±16 mmHg vs. 144±15 mmHg; p&lt;0.001 and 4.1±0.9 vs. 3.5±0.5; p&lt;0001 respectively). RASB-treated patients have significantly longer dialysis vintage (52.7±44.4 months vs. 40.2±40.9 months; p&lt;0.001) and dialysis time (722±87.1 min./week vs. 713±93.4 min./week;p&lt;0.017) than counterparts. Serum potassium was slightly but significantly higher in RASB (5.3±0.8 mmol/L vs. 5.1±0.7 mmol/L;p&lt;0.01). In the real world setting, RASB can be safely used in HD patients treated with diuretics with preserved residual diuresis. Given that many HD patients present numerous multimorbidities, RASB should not only be considered as an additional hypotensive drug in poorly controlled hypertension but also in other compelling indications in HD patients. The tendency toward hyperkalemia in HD patients could be effectively managed with appropriate diet and HD prescription adjustments.