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  1. Fulltext Design of Learning Environment for Undergraduate Comprehensive Literacy Education under Blended Learning Environment
    Wang X, Yu L, Wang Z
    J Environ Public Health, 2022;2022:9602876.
    PMID: 36200091 DOI: 10.1155/2022/9602876
    Blended learning has become the dominant teaching approach in colleges and universities as they evolve. A good learning environment design can represent college and university teaching quality, improve undergraduates' literacy, and boost talent training. This paper introduces the data mining method of undergraduate comprehensive literacy education, discovers the association rules of the evaluation data, and introduces the undergraduate comprehensive literacy evaluation model and BP neural network model driven by theory and technology in a mixed learning environment, which promotes students' comprehensive literacy evaluation and builds a good learning environment. The results demonstrate that undergraduate classification prediction accuracy is similar by data mining, and most reach 99.58 percent. So, whether it is the training sample or the test sample, the prediction result of undergraduate comprehensive literacy is acceptable, which illustrates the validity of the data mining algorithm model and has strong application importance for developing a better learning environment.
  2. Fulltext The impact of digital inclusive finance on environmental pollution: A case study of air pollution
    Wang Z, Fan M, Fan Y
    PLoS One, 2024;19(7):e0305963.
    PMID: 39047026 DOI: 10.1371/journal.pone.0305963
    This study delves into the impact of digital inclusive finance on environmental pollution, with a specific focus on air pollution. Utilizing data from 265 Chinese cities, advanced econometric methods such as the bi-directional fixed effects model, threshold model, spatial Durbin model, and multi-period difference-in-differences model are employed, incorporating a variety of control variables. The empirical findings indicate that digital inclusive finance significantly reduces air pollution. This mechanism chiefly operates through enhancing public environmental consciousness and fostering green technological innovation. The study also uncovers the spatial spillover effect and non-linear characteristics of digital inclusive finance on air pollution, along with its interactive effects with specific policies (e.g., smart city pilot policies and the "major protection, no major development" initiative). Moreover, heterogeneity analysis reveals regional variations in the environmental effects of digital inclusive finance. These insights provide a novel perspective on the relationship between financial technology and environmental protection and offer crucial guidance for policymaking.
  3. Inhibitory cueing effects following manual and saccadic responses to arrow cues
    Ding Y, He T, Satel J, Wang Z
    Atten Percept Psychophys, 2016 05;78(4):1020-9.
    PMID: 26956560 DOI: 10.3758/s13414-016-1079-6
    With two cueing tasks, in the present study we examined output-based inhibitory cueing effects (ICEs) with manual responses to arrow targets following manual or saccadic responses to arrow cues. In all experiments, ICEs were observed when manual localization responses were required to both the cues and targets, but only when the cue-target onset asynchrony (CTOA) was 2,000 ms or longer. In contrast, when saccadic responses were made in response to the cues, ICEs were only observed with CTOAs of 2,000 ms or less-and only when an auditory cue-back signal was used. The present study also showed that the magnitude of ICEs following saccadic responses to arrow cues decreased with time, much like traditional inhibition-of-return effects. The magnitude of ICEs following manual responses to arrow cues, however, appeared later in time and had no sign of decreasing even 3 s after cue onset. These findings suggest that ICEs linked to skeletomotor activation do exist and that the ICEs evoked by oculomotor activation can carry over to the skeletomotor system.
  4. Fulltext Synchronization of the neurons coupled with sequential developing electrical and chemical synapses
    Wang Z, Ramamoorthy R, Xi X, Namazi H
    Math Biosci Eng, 2022 Jan;19(2):1877-1890.
    PMID: 35135233 DOI: 10.3934/mbe.2022088
    There is some evidence representing the sequential formation and elimination of electrical and chemical synapses in particular brain regions. Relying on this feature, this paper presents a purely mathematical modeling study on the synchronization among neurons connected by transient electrical synapses transformed to chemical synapses over time. This deletion and development of synapses are considered consecutive. The results represent that the transient synapses lead to burst synchronization of the neurons while the neurons are resting when both synapses exist constantly. The period of the transitions and also the time of presence of electrical synapses to chemical ones are effective on the synchronization. The larger synchronization error is obtained by increasing the transition period and the time of chemical synapses' existence.
  5. Two new species and one new record of the genus Asprothrips (Thysanoptera: Thripidae) from China
    Tong X, Wang Z, Mirab-Balou M
    Zootaxa, 2016 Jan 05;4061(2):181-8.
    PMID: 27395492 DOI: 10.11646/zootaxa.4061.2.8
    Two new species of the genus Asprothrips Crawford, A. bucerus sp. n. and A. punctulosus sp. n. are described and illustrated from China. A. bimaculatus Michel & Ryckewaert, previously known only from Martinique in the French West Indies and Malaysia, is newly recorded from mainland China and Taiwan, along with the first descriptive notes of the male, and the record from China of A. fuscipennis Kudô is considered a misidentification of A. bucerus sp. n. The generic diagnosis of Asprothrips is briefly summarized and an updated key to world species of the genus is also presented.
  6. Fulltext Electromagnetic Wave Absorption Performance of Carbonized Rice Husk Obtained at Various Temperatures
    Melvin GJH, Wang Z, Ni QQ
    Glob Chall, 2019 Nov;3(11):1900045.
    PMID: 31693011 DOI: 10.1002/gch2.201900045
    Agricultural wastes such as rice husks (RHs) are valuable due to their feasibility to be converted into carbon materials, low cost, and abundancy in contrast to the conventional carbon material sources. In this study, RHs are carbonized at various temperatures from low to high temperatures, and their electromagnetic (EM) wave absorption properties are evaluated. Carbon materials, silicon carbide (SiC) whiskers, and SiC particles are obtained from RHs carbonized at 1500 °C (CRH1500) for 0.5 h with presence of Ar gas at 1 atm. In order to evaluate their EM wave absorption performance, complex permittivity and permeability are measured by using vector network analyzer, and the values are utilized in the reflection loss (R.L.) calculation according to the transmission line theory. CRH1500, 40 wt% with thickness of 1.6 mm exhibits minimum R.L. of ≈-55.4 dB (>99.9997% absorption) at 11.37 GHz and response bandwidth (R.L. < 10 dB, > 90% absorption) of 4.21 GHz. Low-cost and abundant RHs, carbonized at various temperatures, show significant absorption performance. Their absorption performance and response bandwidth are highly dependent on matching thickness, indicating that they can be easily modulated for promising electromagnetic wave absorber materials.
  7. Burden and trends of iodine deficiency in Asia from 1990 to 2019
    Wei R, Wang Z, Zhang X, Wang X, Xu Y, Li Q
    Public Health, 2023 Sep;222:75-84.
    PMID: 37531713 DOI: 10.1016/j.puhe.2023.06.034
    OBJECTIVES: Understanding iodine deficiency (ID) burdens and trends in Asia can help guide effective intervention strategies. This study aims to report the incidence, prevalence, and disability-adjusted life years (DALYs) of ID in 48 Asian countries during the period 1990-2019.

    STUDY DESIGN: Data on ID were retrieved from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 and estimated by age, sex, geographical region, and sociodemographic index (SDI).

    METHODS: The estimated annual percentage change (EAPC) was calculated to evaluate the changing trend of age-standardized incidence rate (ASIR), age-standardized prevalence rate (ASPR), and age-standardized DALYs rate (ASDR) related to ID during the period 1990-2019.

    RESULTS: In Asia, there were 126,983,965.8 cases with 5,466,213.1 new incidence and 1,765,995.5 DALYs of ID in 2019. Between 1999 and 2019, the EAPC in ASIR, ASPR and ASDR were -0.6 (95% confidence interval [CI], -0.8 to -0.4), -0.9 (95% CI, -1.2 to -0.7), and -1.6 (95% CI, -1.8 to -1.5), respectively. Malaysia charted the largest decrease in ASIR, ASPR, and ASDR (82.4%, 85.3%, and 80.9% separately), whereas the Philippines and Pakistan were the only two countries that witnessed an increase in ASIR and ASPR. ID burdens were more pronounced in women, countries located to the south of the Himalayas, and low-middle SDI regions.

    CONCLUSIONS: The incidence, prevalence, and DALYs of ID in Asia substantially decreased from 1990 to 2019. Women and low-middle SDI countries have relatively high ID burdens. Governments need to pay constant attention to the implementation and monitoring of universal salt iodization.

  8. Mapping the cumulative impacts of long-term mining disturbance and progressive rehabilitation on ecosystem services
    Wang Z, Lechner AM, Yang Y, Baumgartl T, Wu J
    Sci Total Environ, 2020 May 15;717:137214.
    PMID: 32062237 DOI: 10.1016/j.scitotenv.2020.137214
    Open-cut coal mining can seriously disturb and reshape natural landscapes which results in a range of impacts on local ecosystems and the services they provide. To address the negative impacts of disturbance, progressive rehabilitation is commonly advocated. However, there is little research focusing on how these impacts affect ecosystem services within mine sites and changes over time. The aim of this study was to assess the cumulative impacts of mining disturbance and rehabilitation on ecosystem services through mapping and quantifying changes at multiple spatial and temporal scales. Four ecosystem services including carbon sequestration, air quality regulation, soil conservation and water yield were assessed in 1989, 1997, 2005 and 2013. Disturbance and rehabilitation was mapped using LandTrendr algorithm with Landsat. We mapped spatial patterns and pixel values for each ecosystem service with corresponding model and the landscape changes were analyzed with landscape metrics. In addition, we assessed synergies and trade-offs using Spearman's correlation coefficient for different landscape classes and scales. The results showed that carbon sequestration, air quality regulation and water yield services were both positively and negatively affected by vegetation cover changes due to mined land disturbance and rehabilitation, while soil conservation service were mainly influenced by topographic changes. There were strong interactions between carbon sequestration, air quality regulation and water yield, which were steady among different spatial scales and landscape types. Soil conservation correlations were weak and changed substantially due to differences of spatial scales and landscape types. Although there are limitations associated with data accessibility, this study provides a new research method for mapping impacts of mining on ecosystem services, which offer spatially explicit information for decision-makers and environmental regulators to carry out feasible policies, balancing mining development with ecosystem services provision.
  9. A novel chitinous nanoparticles prepared and characterized with black soldier fly (Hermetia illucens L.) using steam flash explosion treatment
    Feng H, Wang Z, Sajab MS, Abdul PM, Ding G
    Int J Biol Macromol, 2023 Jan 10;230:123210.
    PMID: 36639077 DOI: 10.1016/j.ijbiomac.2023.123210
    This is the first report of the use of steam flash explosion (SFE) to prepare chitinous nanoparticles from black soldier fly (BSF). SFE treatment was performed at a steam pressure of 0.45 to 1.60 MPa with a holding time of 60 s. As the pressure increased, the particle size of the chitinous particles decreased. Under SFE at 1.60 MPa, chitinous nanoparticles with sizes ranging from 59 to 162 nm were produced. SEM, AFM, Raman spectroscopy, FT-IR spectroscopy, 1H NMR, TGA, and DSC were used to characterize the BSF chitin materials. It was demonstrated that SFE treatment deacetylated chitin to obtain chitosan with 91.24 % deacetylation. In addition, the polymer backbone was maintained, and the degree of polymerization of chitosan nanoparticles was reduced. The activity of the cationic groups of chitosan nanoparticles was improved, thereby enhancing the temperature sensitivity of the polymeric material. It can be concluded that the SFE one-step processing method is a simple and efficient way to prepare homogeneous biomaterial nanoparticles. This study has implications for the development of chitosan nanomaterials for biomedical applications.
  10. Does globalization increase the ecological footprint? Empirical evidence from Malaysia
    Ahmed Z, Wang Z, Mahmood F, Hafeez M, Ali N
    Environ Sci Pollut Res Int, 2019 Jun;26(18):18565-18582.
    PMID: 31054053 DOI: 10.1007/s11356-019-05224-9
    This study focuses to investigate the relationship between globalization and the ecological footprint for Malaysia from 1971 to 2014. The results of the Bayer and Hanck cointegration test and the ARDL bound test show the existence of cointegration among variables. The findings disclose that globalization is not a significant determinant of the ecological footprint; however, it significantly increases the ecological carbon footprint. Energy consumption and economic growth stimulate the ecological footprint and carbon footprint in Malaysia. Population density reduces the ecological footprint and carbon footprint. Further, financial development mitigates the ecological footprint. The causality results disclose the feedback hypothesis between energy consumption and economic growth in the long run and short run.
  11. The influence of picture book design on visual attention of children with autism: a pilot study
    Lian X, Hong WCH, Xu X, Kimberly KZ, Wang Z
    Int J Dev Disabil, 2023;69(6):946-956.
    PMID: 37885844 DOI: 10.1080/20473869.2022.2033590
    Taking 22 children with mild and moderate autism as subjects and using the TobiiX 120 eye-tracker to record their eye movements in visual search of images in picture books, the characteristics of the process of autistic children viewing picture books were explored. Two measures, fixation counts and gaze duration, were used alongside attention heatmap, to explore the visual patterns among children with autism viewing two types of researcher-made picture books and an ordinary picture book. Using a within-subject design, it was found that children with autism could sustain longer gaze duration and have more fixation points on the effective area of the picture book content when viewing researcher-made picture books than when viewing the ordinary picture book, suggesting better visual attention to single-object and single-pattern picture books. The study offers insights and support for related picture book reading and teaching in the future.
  12. An efficient intrusion detection model based on convolutional spiking neural network
    Wang Z, Ghaleb FA, Zainal A, Siraj MM, Lu X
    Sci Rep, 2024 Mar 25;14(1):7054.
    PMID: 38528084 DOI: 10.1038/s41598-024-57691-x
    Many intrusion detection techniques have been developed to ensure that the target system can function properly under the established rules. With the booming Internet of Things (IoT) applications, the resource-constrained nature of its devices makes it urgent to explore lightweight and high-performance intrusion detection models. Recent years have seen a particularly active application of deep learning (DL) techniques. The spiking neural network (SNN), a type of artificial intelligence that is associated with sparse computations and inherent temporal dynamics, has been viewed as a potential candidate for the next generation of DL. It should be noted, however, that current research into SNNs has largely focused on scenarios where limited computational resources and insufficient power sources are not considered. Consequently, even state-of-the-art SNN solutions tend to be inefficient. In this paper, a lightweight and effective detection model is proposed. With the help of rational algorithm design, the model integrates the advantages of SNNs as well as convolutional neural networks (CNNs). In addition to reducing resource usage, it maintains a high level of classification accuracy. The proposed model was evaluated against some current state-of-the-art models using a comprehensive set of metrics. Based on the experimental results, the model demonstrated improved adaptability to environments with limited computational resources and energy sources.
  13. Mouse Models for Head and Neck Squamous Cell Carcinoma
    Zhou J, Liu C, Amornphimoltham P, Cheong SC, Gutkind JS, Chen Q, et al.
    J Dent Res, 2024 Jun;103(6):585-595.
    PMID: 38722077 DOI: 10.1177/00220345241240997
    The prognosis and survival rate of head and neck squamous cell carcinoma (HNSCC) have remained unchanged for years, and the pathogenesis of HNSCC is still not fully understood, necessitating further research. An ideal animal model that accurately replicates the complex microenvironment of HNSCC is urgently needed. Among all the animal models for preclinical cancer research, tumor-bearing mouse models are the best known and widely used due to their high similarity to humans. Currently, mouse models for HNSCC can be broadly categorized into chemical-induced models, genetically engineered mouse models (GEMMs), and transplanted mouse models, each with its distinct advantages and limitations. In chemical-induced models, the carcinogen spontaneously initiates tumor formation through a multistep process. The resemblance of this model to human carcinogenesis renders it an ideal preclinical platform for studying HNSCC initiation and progression from precancerous lesions. The major drawback is that these models are time-consuming and, like human cancer, unpredictable in terms of timing, location, and number of lesions. GEMMs involve transgenic and knockout mice with gene modifications, leading to malignant transformation within a tumor microenvironment that recapitulates tumorigenesis in vivo, including their interaction with the immune system. However, most HNSCC GEMMs exhibit low tumor incidence and limited prognostic significance when translated to clinical studies. Transplanted mouse models are the most widely used in cancer research due to their consistency, availability, and efficiency. Based on the donor and recipient species matching, transplanted mouse models can be divided into xenografts and syngeneic models. In the latter, transplanted cells and host are from the same strain, making syngeneic models relevant to study functional immune system. In this review, we provide a comprehensive summary of the characteristics, establishment methods, and potential applications of these different HNSCC mouse models, aiming to assist researchers in choosing suitable animal models for their research.
  14. Fulltext A meta-analysis of the effect of the Early Start Denver Model in children with autism spectrum disorder
    Wang Z, Loh SC, Tian J, Chen QJ
    Int J Dev Disabil, 2022;68(5):587-597.
    PMID: 36210899 DOI: 10.1080/20473869.2020.1870419
    Objectives: To examine and analyse the intervention effects of the Early Start Denver Model (ESDM) on children with autism spectrum disorder (ASD). Methods: This meta-analysis evaluated the effect sizes in four major domains of measurement (autism symptoms, language, cognition, and social communication). A total of 624 participants with ASD were included in 11 high-quality randomized controlled trial studies. Results: The results indicated that the ESDM intervention resulted in significant improvement with moderate effect sizes in the cognition (g = 0.28), autism symptoms (g = 0.27), and language (g = 0.29) domains. The effect sizes of autism symptoms and language were moderated by country (Western versus Asian countries). However, there were no significant effects observed for the social communication domain. Conclusion: The ESDM intervention significantly improved autism symptoms, language, and cognition. The effect sizes of autism symptoms and language were larger in Asian countries than in Western countries.
  15. Fulltext Chromosome 7 aneuploidy in clear cell and papillary renal cell carcinoma: detection using silver in situ hybridization technique
    Pailoor J, Rajandram R, Yap NY, Ng KL, Wang Z, Iyengar KR
    Indian J Pathol Microbiol, 2013 Apr-Jun;56(2):98-102.
    PMID: 24056643 DOI: 10.4103/0377-4929.118688
    Chromosome 7 aberrations in renal cell carcinoma (RCC) have been reported in papillary renal cell carcinoma (pRCC) and clear cell renal cell carcinoma (ccRCC). However, the implication of these anomalies on prognosis and survival is still unclear. RCC Chromosome 7 aberrations have commonly been detected by fluorescent in situ hybridization and chromogenic in situ hybridization but not silver in situ hybridization (SISH).
  16. Pre-surgical Administration of Microbial Cell Preparation in Colorectal Cancer Patients: A Randomized Controlled Trial
    Tan CK, Said S, Rajandram R, Wang Z, Roslani AC, Chin KF
    World J Surg, 2016 08;40(8):1985-92.
    PMID: 27098538 DOI: 10.1007/s00268-016-3499-9
    INTRODUCTION: Disruption of normal gut function is a common side effect post abdominal surgery. It may result in reduced tolerance to oral nutrition and progress to postoperative ileus. Microbial cell preparation is beneficial as a pre-surgical nutritional supplement to aid in bowel recovery and promote the return of normal gut function following abdominal surgery. The aim of this study was to evaluate the efficacy of pre-surgical administration of microbial cell preparation in promoting the return of normal gut function.

    METHOD: The study is a randomized, double-blind, placebo-controlled trial. In total, 40 patients were recruited. Patients were randomized to receive either microbial cell preparation (n = 20) or placebo (n = 20) for 7 days prior to elective surgery. The primary end point was the time to return of normal gut function, while the secondary end point was the duration of hospital stay.

    RESULTS: The treatment group demonstrated significantly faster return of normal gut function with a median of 108.5 h (80-250 h) which was 48 h earlier than the placebo group at a median of 156.5 h (94-220 h), p = 0.022. The duration of hospital stay in the treatment group was also shorter at a median of 6.5 days (4-30 days), in comparison to the placebo group at 13 days (5-25 days), p = 0.012.

    CONCLUSION: Pre-surgical administration of microbial cell preparation promotes the return of normal gut function in patients after colorectal cancer surgery, thus associated with faster recovery and shorter duration of hospital stay.

  17. Molecular cloning and expression of five glutathione S-transferase (GST) genes from Banana (Musa acuminata L. AAA group, cv. Cavendish)
    Wang Z, Huang S, Jia C, Liu J, Zhang J, Xu B, et al.
    Plant Cell Rep, 2013 Sep;32(9):1373-80.
    PMID: 23652818 DOI: 10.1007/s00299-013-1449-7
    KEY MESSAGE: Three tau class MaGSTs responded to abiotic stress, MaGSTF1 and MaGSTL1 responded to signaling molecules, they may play an important role in the growth of banana plantlet. Glutathione S-transferases (GST) are multifunctional detoxification enzymes that participate in a variety of cellular processes, including stress responses. In this study, we report the molecular characteristics of five GST genes (MaGSTU1, MaGSTU2, MaGSTU3, MaGSTF1 and MaGSTL1) cloned from banana (Musa acuminate L. AAA group, cv. Cavendish) using a RACE-PCR-based strategy. The predicted molecular masses of these GSTs range from 23.4 to 27.7 kDa and their pIs are acidic. At the amino acid level, they share high sequence similarity with GSTs in the banana DH-Pahang (AA group) genome. Phylogenetic analysis showed that the deduced amino acid sequences of MaGSTs also have high similarity to GSTs of other plant species. Expression analysis by semi-quantitative RT-PCR revealed that these genes are differentially expressed in various tissues. In addition, their expression is regulated by various stress conditions, including exposure to signaling molecules, cold, salinity, drought and Fusarium oxysporum f specialis(f. Sp) cubense Tropical Race 4 (Foc TR4) infection. The expression of the tau class MaGSTs (MaGSTU1, MaGSTU2 and MaGSTU3) mainly responded to cold, salinity and drought while MaGSTF1 and MaGSTL1 expressions were upregulated by signaling molecules. Our findings suggest that MaGSTs play a key role in both development and abiotic stress responses.
  18. Fulltext Perilla frutescens Leaf Extract and Fractions: Polyphenol Composition, Antioxidant, Enzymes (α-Glucosidase, Acetylcholinesterase, and Tyrosinase) Inhibitory, Anticancer, and Antidiabetic Activities
    Wang Z, Tu Z, Xie X, Cui H, Kong KW, Zhang L
    Foods, 2021 Feb 03;10(2).
    PMID: 33546380 DOI: 10.3390/foods10020315
    This study aims to evaluate the bioactive components, in vitro bioactivities, and in vivo hypoglycemic effect of P. frutescens leaf, which is a traditional medicine-food homology plant. P. frutescens methanol crude extract and its fractions (petroleum ether, chloroform, ethyl acetate, n-butanol fractions, and aqueous phase residue) were prepared by ultrasound-enzyme assisted extraction and liquid-liquid extraction. Among the samples, the ethyl acetate fraction possessed the high total phenolic (440.48 μg GAE/mg DE) and flavonoid content (455.22 μg RE/mg DE), the best antioxidant activity (the DPPH radical, ABTS radical, and superoxide anion scavenging activity, and ferric reducing antioxidant power were 1.71, 1.14, 2.40, 1.29, and 2.4 times higher than that of control Vc, respectively), the most powerful α-glucosidase inhibitory ability with the IC50 value of 190.03 μg/mL which was 2.2-folds higher than control acarbose, the strongest proliferative inhibitory ability against MCF-7 and HepG2 cell with the IC50 values of 37.92 and 13.43 μg/mL, which were considerable with control cisplatin, as well as certain inhibition abilities on acetylcholinesterase and tyrosinase. HPLC analysis showed that the luteolin, rosmarinic acid, rutin, and catechin were the dominant components of the ethyl acetate fraction. Animal experiments further demonstrated that the ethyl acetate fraction could significantly decrease the serum glucose level, food, and water intake of streptozotocin-induced diabetic SD rats, increase the body weight, modulate their serum levels of TC, TG, HDL-C, and LDL-C, improve the histopathology and glycogen accumulation in liver and intestinal tissue. Taken together, P. frutescens leaf exhibits excellent hypoglycemic activity in vitro and in vivo, and could be exploited as a source of natural antidiabetic agent.
  19. Regional suitability prediction of soil salinization based on remote-sensing derivatives and optimal spectral index
    Wang Z, Zhang F, Zhang X, Chan NW, Kung HT, Ariken M, et al.
    Sci Total Environ, 2021 Feb 12;775:145807.
    PMID: 33618298 DOI: 10.1016/j.scitotenv.2021.145807
    Soil salinization is an extremely serious land degradation problem in arid and semi-arid regions that hinders the sustainable development of agriculture and food security. Information and research on soil salinity using remote sensing (RS) technology provide a quick and accurate assessment and solutions to address this problem. This study aims to compare the capabilities of Landsat-8 OLI and Sentinel-2A MSI in RS prediction and exploration of the potential application of derivatives to RS prediction of salinized soils. It explores the ability of derivatives to be used in the Landsat-8 OLI and Sentinel-2A MSI multispectral data, and it was used as a data source as well as to address the adaptability of salinity prediction on a regional scale. The two-dimensional (2D) and three-dimensional (3D) optimal spectral indices are used to screen the bands that are most sensitive to soil salinity (0-10 cm), and RS data and topographic factors are combined with machine learning to construct a comprehensive soil salinity estimation model based on gray correlation analysis. The results are as follows: (1) The optimal spectral index (2D, 3D) can effectively consider possible combinations of the bands between the interaction effects and responding to sensitive bands of soil properties to circumvent the problem of applicability of spectral indices in different regions; (2) Both the Landsat-8 OLI and Sentinel-2A MSI multispectral RS data sources, after the first-order derivative techniques are all processed, show improvements in the prediction accuracy of the model; (3) The best performance/accuracy of the predictive model is for sentinel data under first-order derivatives. This study compared the capabilities of Landsat-8 OLI and Sentinel-2A MSI in RS prediction in finding the potential application of derivatives to RS prediction of salinized soils, with the results providing some theoretical basis and technical guidance for salinized soil prediction and environmental management planning.
  20. Fulltext Formation and Evaluation of Silicon Substrate with Highly-Doped Porous Si Layers Formed by Metal-Assisted Chemical Etching
    Li Y, Van Toan N, Wang Z, Samat KFB, Ono T
    Nanoscale Res Lett, 2021 Apr 20;16(1):64.
    PMID: 33877472 DOI: 10.1186/s11671-021-03524-z
    Porous silicon (Si) is a low thermal conductivity material, which has high potential for thermoelectric devices. However, low output performance of porous Si hinders the development of thermoelectric performance due to low electrical conductivity. The large contact resistance from nonlinear contact between porous Si and metal is one reason for the reduction of electrical conductivity. In this paper, p- and n-type porous Si were formed on Si substrate by metal-assisted chemical etching. To decrease contact resistance, p- and n-type spin on dopants are employed to dope an impurity element into p- and n-type porous Si surface, respectively. Compared to the Si substrate with undoped porous samples, ohmic contact can be obtained, and the electrical conductivity of doped p- and n-type porous Si can be improved to 1160 and 1390 S/m, respectively. Compared with the Si substrate, the special contact resistances for the doped p- and n-type porous Si layer decreases to 1.35 and 1.16 mΩ/cm2, respectively, by increasing the carrier concentration. However, the increase of the carrier concentration induces the decline of the Seebeck coefficient for p- and n-type Si substrates with doped porous Si samples to 491 and 480 μV/K, respectively. Power factor is related to the Seebeck coefficient and electrical conductivity of thermoelectric material, which is one vital factor that evaluates its output performance. Therefore, even though the Seebeck coefficient values of Si substrates with doped porous Si samples decrease, the doped porous Si layer can improve the power factor compared to undoped samples due to the enhancement of electrical conductivity, which facilitates its development for thermoelectric application.
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