Self-oscillating polymeric refrigerator with high energy efficiency.

Electrocaloric1,2 and electrostrictive3,4 effects concurrently exist in dielectric materials. Combining these two effects could achieve the lightweight, compact localized thermal management that is promised by electrocaloric refrigeration5. Despite a handful of numerical models and schematic presentations6,7, current electrocaloric refrigerators still rely on external accessories to drive the working bodies8-10 and hence result in a low device-level cooling power density and coefficient of performance (COP). Here we report an electrocaloric thin-film device that uses the electro-thermomechanical synergy provided by polymeric ferroelectrics. Under one-time a.c. electric stimulation, the device is thermally and mechanically cycled by the working body itself, resulting in an external-driver-free, self-cycling, soft refrigerator. The prototype offers a directly measured cooling power density of 6.5 W g-1 and a peak COP exceeding 58 under a zero temperature span. Being merely a 30-µm-thick polymer film, the device achieved a COP close to 24 under a 4 K temperature span in an open ambient environment (32% thermodynamic efficiency). Compared with passive cooling, the thin-film refrigerator could immediately induce an additional 17.5 K temperature drop against an electronic chip. The soft, polymeric refrigerator can sense, actuate and pump heat to provide automatic localized thermal management.

High-entropy polymer produces a giant electrocaloric effect at low fields.

More than a decade of research on the electrocaloric (EC) effect has resulted in EC materials and EC multilayer chips that satisfy a minimum EC temperature change of 5 K required for caloric heat pumps1-3. However, these EC temperature changes are generated through the application of high electric fields4-8 (close to their dielectric breakdown strengths), which result in rapid degradation and fatigue of EC performance. Here we report a class of EC polymer that exhibits an EC entropy change of 37.5 J kg-1 K-1 and a temperature change of 7.5 K under 50 MV m-1, a 275% enhancement over the state-of-the-art EC polymers under the same field strength. We show that converting a small number of the chlorofluoroethylene groups in poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymer into covalent double bonds markedly increases the number of the polar entities and enhances the polar-nonpolar interfacial areas of the polymer. The polar phases in the polymer adopt a loosely correlated, high-entropy state with a low energy barrier for electric-field-induced switching. The polymer maintains performance for more than one million cycles at the low fields necessary for practical EC cooling applications, suggesting that this strategy may yield materials suitable for use in caloric heat pumps.

Regulation of cervical cancer via G15-mediated inhibition of G protein-coupled estrogen receptor.

Cervical cancer is among the most common gynecological malignancies. G protein-coupled estrogen receptor (GPER) is involved in the development of various tumors; however, its role in cervical cancer remains unclear. We investigated whether G15, an inhibitor of GPER, can regulate its expression and affect cervical cancer progression. We examined the biological behaviors of G15-treated SiHa and HeLa cells using Cell Counting Kit-8, monoclonal proliferation, plate scratching, and Transwell invasion experiments. Western blotting was used to detect the expression of GPER, E-cadherin, N-cadherin, vimentin, Bcl-2, Bax, phosphatidylinositol-3-kinase (PI3K)/AKT, and programmed death ligand 1 (PD-L1). The expression of GPER, E-cadherin, vimentin, and PD-L1 in cervical cancer and adjacent tissues was detected using immunohistochemistry. The correlation between GPER expression and clinicopathological characteristics was analyzed. The expression of GPER in cervical cancer tissues was significantly higher than that in paracancerous tissues, and it was detected in the membrane and cytoplasm of SiHa and HeLa cells. The proliferation, migration, and invasion abilities of SiHa and HeLa cells were reduced after G15 treatment. The G15-treated groups exhibited higher expression of E-cadherin and Bax and lower expression of N-cadherin, vimentin, Bcl-2, GPER, p-PI3K, p-AKT, and PD-L1 than the control group. The expression of E-cadherin was lower and that of vimentin was higher in cancer tissues than in paracancerous tissues; PD-L1 was highly expressed in tumor and stromal cells in cancer tissues but not in paracancerous tissues. G15 functions by regulating the GPER/PI3K/AKT/PD-L1 signaling pathway and may serve as a new immunotherapy for treating patients with cervical cancer.

Factors influencing turnover intention among male nurses in China: A large-scale descriptive correlational study.

AIM: This study examined the correlation among turnover intention, emotional intelligence and job burnout in male nurses and determined its influencing factors. BACKGROUND: The number of male nurses has increased in China; however, the turnover rate is very high. Nurses' turnover intention is related to job burnout and emotional intelligence. INTRODUCTION: Recent studies have shown that job burnout and emotional intelligence are related to medical and health institution employees' intention to leave their jobs. It is not clear if the same conclusions can be drawn about male nurses. METHODS: For this cross-sectional study, 627 male nurses were recruited from across China between May and July 2018. Data were collected through an online questionnaire, and Pearson's product-moment correlation coefficient and multiple linear regression were performed to analyse the data. RESULTS: There was a weak negative, moderate positive and moderate negative correlation between turnover intention and emotional intelligence, turnover intention and job burnout, and emotional intelligence and job burnout, respectively. Factors that significantly affected turnover intention among male nurses included job burnout, young age, lack of interest in nursing and working in the emergency department. CONCLUSION: The study revealed the factors that affected male nurses' turnover intention and the relationships between turnover intention, emotional intelligence and job burnout. IMPLICATIONS FOR NURSING MANAGEMENT AND SOCIAL POLICY: Hospital managers should provide necessary help and support to reduce male nurse turnover rates and incorporate emotional intelligence training. The policy should eliminate the unfair college admission practices for students choosing nursing majors, raise the nursing profession's salaries and vigorously develop specialty nursing. In addition, diversified values should be promoted, and stereotypes of male nurses in nursing should be broken.

Revitalizing mouse diphyodontic dentition formation by inhibiting the sonic hedgehog signaling pathway.

BACKGROUND: Tooth regeneration depends on the longevity of the dental epithelial lamina. However, the exact mechanism of dental lamina regression has not yet been clarified. To explore the role of the Sonic hedgehog (Shh) signaling pathway in regression process of the rudimentary successional dental lamina (RSDL) in mice, we orally administered a single dose of a Shh signaling pathway inhibitor to pregnant mice between embryonic day 13.0 (E13.0) and E17.0. RESULTS: We observed that the Shh signaling pathway inhibitor effectively inhibited the expression of Shh signaling pathway components and revitalized RSDL during E15.0-E17.0 by promoting cell proliferation. In addition, mRNA-seq, reverse transcription plus polymerase chain reaction (RT-qPCR), and immunohistochemical analyses indicated that diphyodontic dentition formation might be related to FGF signal up-regulation and the Sostdc1-Wnt negative feedback loop. CONCLUSIONS: Overall, our results indicated that the Shh signaling pathway may play an initial role in preventing further development of mouse RSDL in a time-dependent manner.

The fusion of keratinized epithelium, an indication of early implant placement in the aesthetic area: an animal study.

BACKGROUND: In the period of the early implant placement, the socket is mainly occupied by provisional matrix (PM). Keratinized epithelium (KE) is critical for primary wound closure. Although both KE and PM are important, the detailed relationship among migrating KE, PM formation and indication of the early implant placement is still unclear. OBJECTIVE: This research aimed to locate a healing stage of KE with highest osteogenic PM formation after tooth extraction, which could be treated as the optimal time point for early implant placement. MATERIAL AND METHODS: Mice were sacrificed on days 1, 2, 3, 4 and 6 after incisor extraction. Clinical, histological, and immunohistochemical evaluations of the extraction sockets were performed, and statistical analyses were conducted. We then inserted implants into the PM with the greatest bioactivity and observed its osseointegration pattern for 3, 10, 17 and 30 days. RESULT: When KE fusion was reached, sockets were dominated by PM with the greatest expression of osteocalcin (OC, P < 0.05) and high levels of CD34 and Runx2. OC and Runx2 expression were positively correlated with KE coverage (P < 0.05). When the implant was inserted at 4 days' healing, the PM maintained its osteogenic ability, and osseointegration proceeded perfectly. CONCLUSION: The migration of KE was correlated with the formation of highly osteogenic and angiogenic PM. And the fusion of KE could be treated as an indication for early implant placement.

Immunogenicity and reactogenicity of homologous mRNA-based and vector-based SARS-CoV-2 vaccine regimens in patients receiving maintenance dialysis.

Patients receiving maintenance dialysis (MD) are vulnerable to COVID-19-related morbidity and mortality. Currently, data on SARS-CoV-2-specific cellular and humoral immunity post-vaccination in this population are scarce. We conducted a prospective single-center study exploring the specific cellular (interferon-γ and interleukin-2 ELISpot assays) and humoral immune responses (dot plot array and chemiluminescent microparticle immunoassay [CMIA]) at 4 weeks and 6 weeks following a single dose or a complete homologous dual dose SARS-CoV-2 vaccine regimen in 60 MD patients (six with a history of COVID-19). Our results show that MD patients exhibit a high seroconversion rate (91.7%) but the anti-spike IgG antibodies (CMIA) tend to wane rapidly after full immunization. Only 51.7% of the patients developed T cell immune response. High anti-spike IgG antibodies may predict a better cellular immunity. While patients with prior COVID-19 showed the best response after one, SARS-CoV-2-naïve patients may benefit from a third vaccine injection.

Osteogenic and angiogenic profiles of the palatal process of the maxilla and the palatal process of the palatine bone.

Hard palate consists anteriorly of the palatal process of the maxilla (ppmx) and posteriorly of the palatal process of the palatine (ppp). Currently, palatal osteogenesis is receiving increasing attention. This is the first study to provide an overview of the osteogenesis process of the mouse hard palate. We found that the period in which avascular mesenchymal condensation becomes a vascularized bone structure corresponds to embryonic day (E) 14.5 to E16.5 in the hard palate. The ppmx and ppp differ remarkably in morphology and molecular respects during osteogenesis. Osteoclasts in the ppmx and ppp are heterogeneous. There was a multinucleated giant osteoclast on the bone surface at the lateral-nasal side of the ppmx, while osteoclasts in the ppp were more abundant and adjacent to blood vessels but were smaller and had fewer nuclei. In addition, bone remodeling in the hard palate was asymmetric and exclusively occurred on the nasal side of the hard palate at E18.5. During angiogenesis, CD31-positive endothelial cells were initially localized in the surrounding of palatal mesenchymal condensation and then invaded the condensation in a sprouting fashion. At the transcriptome level, we found 78 differentially expressed genes related to osteogenesis and angiogenesis between the ppmx and ppp. Fifty-five related genes were up/downregulated from E14.5 to E16.5. Here, we described the morphogenesis and the heterogeneity in the osteogenic and angiogenic genes profiles of the ppmx and ppp, which are significant for subsequent studies of normal and abnormal subjects.

Defining the critical period of hedgehog pathway inhibitor-induced cranial base dysplasia in mice.

BACKGROUND: The hedgehog signaling pathway is critical for developmental patterning of the limb, craniofacial and axial skeleton. Disruption of this pathway in mice leads to a series of structural malformations, but the exact role and critical period of the Hh pathway in the early development of the cranial base have been rarely described. RESULTS: Embryos exposed to vismodegib from E7.5, E9.5, and E10.5 had a higher percentage of cranial base fenestra. The peak incidence of hypoplasia in sphenoid winglets and severe craniosynostosis in cranial base synchondroses was observed when vismodegib was administered between E9.5 and E10.5. Cranial base craniosynostosis results from accelerating terminal differentiation of chondrocytes and premature osteogenesis. CONCLUSIONS: We define the critical periods for the induction of cranial base deformity by vismodegib administration at a meticulous temporal resolution. Our findings suggest that the Hh pathway may play a vital role in the early development of the cranial base. This research also establishes a novel and easy-to-establish mouse model of synostosis in the cranial base using a commercially available pathway-selective inhibitor.

Demystifying COVID-19 publications: institutions, journals, concepts, and topics.

OBJECTIVE: We analyzed the COVID-19 Open Research Dataset (CORD-19) to understand leading research institutions, collaborations among institutions, major publication venues, key research concepts, and topics covered by pandemic-related research. METHODS: We conducted a descriptive analysis of authors' institutions and relationships, automatic content extraction of key words and phrases from titles and abstracts, and topic modeling and evolution. Data visualization techniques were applied to present the results of the analysis. RESULTS: We found that leading research institutions on COVID-19 included the Chinese Academy of Sciences, the US National Institutes of Health, and the University of California. Research studies mostly involved collaboration among different institutions at national and international levels. In addition to bioRxiv, major publication venues included journals such as The BMJ, PLOS One, Journal of Virology, and The Lancet. Key research concepts included the coronavirus, acute respiratory impairments, health care, and social distancing. The ten most popular topics were identified through topic modeling and included human metapneumovirus and livestock, clinical outcomes of severe patients, and risk factors for higher mortality rate. CONCLUSION: Data analytics is a powerful approach for quickly processing and understanding large-scale datasets like CORD-19. This approach could help medical librarians, researchers, and the public understand important characteristics of COVID-19 research and could be applied to the analysis of other large datasets.

High-accuracy optical convolution unit architecture for convolutional neural networks by cascaded acousto-optical modulator arrays.

Optical neural networks (ONNs) have become competitive candidates for the next generation of high-performance neural network accelerators because of their low power consumption and high-speed nature. Beyond fully-connected neural networks demonstrated in pioneer works, optical computing hardwares can also conduct convolutional neural networks (CNNs) by hardware reusing. Following this concept, we propose an optical convolution unit (OCU) architecture. By reusing the OCU architecture with different inputs and weights, convolutions with arbitrary input sizes can be done. A proof-of-concept experiment is carried out by cascaded acousto-optical modulator arrays. When the neural network parameters are ex-situ trained, the OCU conducts convolutions with SDR up to 28.22 dBc and performs well on inferences of typical CNN tasks. Furthermore, we conduct in situ training and get higher SDR at 36.27 dBc, verifying the OCU could be further refined by in situ training. Besides the effectiveness and high accuracy, the simplified OCU architecture served as a building block could be easily duplicated and integrated to future chip-scale optical CNNs.

Optimization and application of reflective LSPR optical fiber biosensors based on silver nanoparticles.

In this study, we developed a reflective localized surface plasmon resonance (LSPR) optical fiber sensor, based on silver nanoparticles (Ag NPs). To enhance the sensitivity of the LSPR optical sensor, two key parameters were optimized, the length of the sensing area and the coating time of the Ag NPs. A sensing length of 1.5 cm and a 1-h coating time proved to be suitable conditions to produce highly sensitive sensors for biosensing. The optimized sensor has a high refractive index sensitivity of 387 nm/RIU, which is much higher than that of other reported individual silver nanoparticles in solutions. Moreover, the sensor was further modified with antigen to act as a biosensor. Distinctive wavelength shifts were found after each surface modification step. In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

Research on the role and mechanism of IL-17 in intervertebral disc degeneration.

Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.

Spatial patterns of urban expansion and cropland loss during 2017-2022 in Guangdong, China.

Urban expansion often occurs at the expense of cropland loss, posing challenges to sustainable urban growth and food security. However, detailed investigations into urban expansion and cropland loss remain limited, particularly in regions with varying levels of urbanization. Here, we take Guangdong Province, China, as a case study to exemplify how urban expansion affects cropland using remotely sensed land use products. We adopted geospatial analysis, correlation indicators, and landscape metrics to uncover their spatial relationships at 10-m spatial resolutions. Results showed that urban areas increased by 6335 km2 while cropland decreased by 3780 km2 from 2017 to 2022. Notably, 41 % of newly expanded urban areas were from croplands, and 45 % of lost croplands were converted to urban areas. Western Guangdong experienced the largest extent of urban expansion and cropland loss, emerging as a hotspot region in recent years. Additionally, our analysis observed the increasing compactness of urban areas and the growing fragmentation of cropland landscapes over time. These findings shed light on the intricate dynamics between urban expansion and cropland loss in rapidly urbanizing regions, which provide valuable insights for sustainable urban development, agricultural practice, and land management in the future.

National-scale 10-m maps of cropland use intensity in China during 2018-2023.

The amount of actively cultivated land in China is increasingly threatened by rapid urbanization and rural population aging. Quantifying the extent and changes of active cropland and cropping intensity is crucial to global food security. However, national-scale datasets for smallholder agriculture are limited in spatiotemporal continuity, resolution, and precision. In this paper, we present updated annual Cropland Use Intensity maps in China (China-CUI10m) with descriptions of the extent of fallow/abandoned, actively cropped fields and cropping intensity at a 10-m resolution in recent six years (2018-2023). The dataset is produced by robust algorithms with no requirements for regional adjustments or intensive training samples, which take full advantage of the Sentinel-1 (S1) SAR and Sentinel-2 (S2) MSI time series. The China-CUI10m maps have achieved high accuracy when compared to ground truth data (Overall accuracy = 90.88%) and statistical data (R2 > 0.94). This paper provides the recent trends in cropland abandonment and agricultural intensification in China, which contributes to facilitating geographic-targeted cropland use control policies towards sustainable intensification of smallholder agricultural systems in developing countries.

Low-k nano-dielectrics facilitate electric-field induced phase transition in high-k ferroelectric polymers for sustainable electrocaloric refrigeration.

Ferroelectric polymer-based electrocaloric effect may lead to sustainable heat pumps and refrigeration owing to the large electrocaloric-induced entropy changes, flexible, lightweight and zero-global warming potential. Herein, low-k nanodiamonds are served as extrinsic dielectric fillers to fabricate polymeric nanocomposites for electrocaloric refrigeration. As low-k nanofillers are naturally polar-inactive, hence they have been widely applied for consolidate electrical stability in dielectrics. Interestingly, we observe that the nanodiamonds markedly enhances the electrocaloric effect in relaxor ferroelectrics. Compared with their high-k counterparts that have been extensively studied in the field of electrocaloric nanocomposites, the nanodiamonds introduces the highest volumetric electrocaloric enhancement (~23%/vol%). The resulting polymeric nanocomposite exhibits concurrently improved electrocaloric effect (160%), thermal conductivity (175%) and electrical stability (125%), which allow a fluid-solid coupling-based electrocaloric refrigerator to exhibit an improved coefficient of performance from 0.8 to 5.3 (660%) while maintaining high cooling power (over 240 W) at a temperature span of 10 K.

Self-regulated underwater phototaxis of a photoresponsive hydrogel-based phototactic vehicle.

Incorporating a negative feedback loop in a synthetic material to enable complex self-regulative behaviours akin to living organisms remains a design challenge. Here we show that a hydrogel-based vehicle can follow the directions of photonic illumination with directional regulation inside a constraint-free, fluidic space. By manipulating the customized photothermal nanoparticles and the microscale pores in the polymeric matrix, we achieved strong chemomechanical deformation of the soft material. The vehicle swiftly assumes an optimal pose and creates directional flow around itself, which it follows to achieve robust full-space phototaxis. In addition, this phototaxis enables a series of complex underwater locomotions. We demonstrate that this versatility is generated by the synergy of photothermofluidic interactions resulting in closed-loop self-control and fast reconfigurability. The untethered, electronics-free, ambient-powered hydrogel vehicle manoeuvres through obstacles agilely, following illumination cues of moderate intensities, similar to that of natural sunlight.

Research progress in decellularized extracellular matrix hydrogels for intervertebral disc degeneration.

As one of the most common clinical disorders, low back pain (LBP) influences patient quality of life and causes substantial social and economic burdens. Many factors can result in LBP, the most common of which is intervertebral disc degeneration (IDD). The progression of IDD cannot be alleviated by conservative or surgical treatments, and gene therapy, growth factor therapy, and cell therapy have their own limitations. Recently, research on the use of hydrogel biomaterials for the treatment of IDD has garnered great interest, and satisfactory treatment results have been achieved. This article describes the classification of hydrogels, the methods of decellularized extracellular matrix (dECM) production and the various types of gel formation. The current research on dECM hydrogels for the treatment of IDD is described in detail in this article. First, an overview of the material sources, decellularization methods, and gel formation methods is given. The focus is on research performed over the last three years, which mainly consists of bovine and porcine NP tissues, while for decellularization methods, combinations of several approaches are primarily used. dECM hydrogels have significantly improved mechanical properties after the polymers are cross-linked. The main effects of these gels include induction of stem cell differentiation to intervertebral disc (IVD) cells, good mechanical properties to restore IVD height after polymer cross-linking, and slow release of exosomes. Finally, the challenges and problems still faced by dECM hydrogels for the treatment of IDD are summarised, and potential solutions are proposed. This paper is the first to summarise the research on dECM hydrogels for the treatment of IDD and aims to provide a theoretical reference for subsequent studies.

Correlation Study Between Bone Cement Distribution and Adjacent Vertebral Fractures After Percutaneous Vertebroplasty.

OBJECTIVE: We investigated the correlation between bone cement distribution and adjacent vertebral fractures (AVFs) after percutaneous vertebroplasty (PVP). METHODS: We retrospectively analyzed patients who underwent single-segment PVP for osteoporotic compression fractures in our hospital from January 2016 to January 2021 and divided the patients into 2 groups, A and B, on the basis of the criterion of whether there were AVFs of the operated vertebrae within 1 year after surgery. We compared the general data of the 2 groups, assessed the ability of 3 simple X-ray-based evaluation methods to predict the occurrence of AVF within 1 year after surgery and derived a simple and accurate evaluation method. RESULTS: A total of 570 patients were included in this study: 511 patients in group A and 59 patients in group B. There were no statistical differences in the general data such as age, gender, and fracture site between the 2 groups. The posterior-anterior (PA), lateral (LAT), and PA and LAT methods showed receiver operating characteristic curve (ROC) predicted postoperative AVF of 0.611, 0.691, and 0.714, respectively. The difference between the area under curve (AUC) of the PA method and LAT method was statistically significant (P = 0.0307), the difference between the AUC of PA method and PA and LAT method was statistically significant (P < 0.001), and the difference between the AUC of LAT method and PA and LAT method was not statistically significant (P = 0.3308).There was no statistical difference between the 2 groups of patients with PA method point of 1 and statistically different between patients with points of 2 and 3. There was statistical difference in points of 1, 2 and 3 in the LAT method between the 2 groups. There was a positive correlation between cement distribution scores and AVF by linear regression analysis of the 3 evaluation methods. CONCLUSIONS: The 3 evaluation methods reliably predict AVF after PVP, with the LAT method, PA and LAT method being more predictive than the PA method, but the LAT method is simpler, with bone cement being widely distributed after crossing the midline in the PA method and contact with the upper and lower end plates in the LAT method being a risk factor for AVF.

Spatio-temporal association mining of intercity PM2.5 pollution: Hubei Province in China as an example.

The complex interaction between emissions, meteorology, and atmospheric chemistry makes accurate predictions of particulate pollution difficult. Advanced data mining techniques can reveal potential laws, providing new possibilities for understanding the evolution and causes of air pollution. Based on the Granger method and block modeling analysis, this paper explored the intercity spillover effects of hourly PM2.5 in Hubei Province, China, to determine the specific role (i.e., overflow, limited overflow, bilateral, inflow, and limited inflow) of each city on regional pollution formation. Furthermore, a dynamic Apriori algorithm considering time-lag effects was used to mine the spatio-temporal associations of extreme PM2.5 pollution events among different cities. Results suggest that the northern and central cities with high-level PM2.5 concentration in Hubei have a significant spillover effect, whereas the eastern and southern cities generally play a role as the sink of pollutants. Based on the association rules of extreme PM2.5 pollution, four main pollutant transport channels were excavated and well matched with the trajectories extracted by the atmospheric model. This paper provides new insights for exploring the interaction of intercity particulate pollution, which is a supplement and cross-validation of the model results.