Online reviews provide additional product information to reduce uncertainty. Hence, consumers often rely on online reviews to form purchase decisions. However, an explosion of online reviews brings ...the problem of information overload to individuals. Identifying reviews containing valuable information from large numbers of reviews becomes increasingly important to both consumers and companies, especially for experience products, such as attractions. Several online review platforms provide a function for readers to rate a review as “helpful” when it contains valuable information. Different from consumers, companies want to detect potential valuable reviews before they are rated to avoid or promote their negative or positive influence, respectively. Using online attraction review data retrieved from TripAdvisor, we conduct a two-level empirical analysis to explore factors that affect the value of reviews. We introduc a negative binomial regression model at a review level to explore the effects of the actual reviews. Subsequently, we apply a Tobit regression model at the reviewer level to investigate the effects of reviewer characteristics inferred from properties of historical rating distribution. The empirical analysis results indicate that both text readability and reviewer characteristics affect the perceived value of reviews. These findings have direct implications for attraction managers in their improved identification of potential valuable reviews.
•A novel econometric model is introduced for data analysis.•A dataset comprising reviewer historical information is built.•The effects of reviewers' historical rating distributions are explored.•The effect of text readability is confirmed in attraction reviews.•The study results benefit attraction management.
The objective of this research aimed to investigate the correlation involving serum albumin with diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).
From 2011 to 2020, the ...National Health and Nutrition Examination Survey (NHANES) surveyed 45462 participants. We used the relevant data to conduct descriptive statistics, linear regression, and Logistic regression analysis.
After adjusting for age, sex, and race, as well as all other variables, serum albumin was significantly negatively related to DR (P<0.001). Furthermore, after controlling for confounding factors, the third quartile (Q3) and the fourth quartile (Q4) had quite a negative significant relationship with the incidence of DR (P<0.01). The second quartile had a significant positive correlation with DR, whereas the observed negative correlations were not statistically meaningful (P>0.05).
Albumin levels in the serum have a quantitatively significant negative correlation with DR. Serum albumin levels in the blood can be used as a reference point for protracted follow-up of people with T2DM.
In this correspondence, we propose a novel method to extract illumination insensitive features for face recognition under varying lighting called the gradient faces. Theoretical analysis shows ...gradient faces is an illumination insensitive measure, and robust to different illumination, including uncontrolled, natural lighting. In addition, gradient faces is derived from the image gradient domain such that it can discover underlying inherent structure of face images since the gradient domain explicitly considers the relationships between neighboring pixel points. Therefore, gradient faces has more discriminating power than the illumination insensitive measure extracted from the pixel domain. Recognition rates of 99.83% achieved on PIE database of 68 subjects, 98.96% achieved on Yale B of ten subjects, and 95.61% achieved on Outdoor database of 132 subjects under uncontrolled natural lighting conditions show that gradient faces is an effective method for face recognition under varying illumination. Furthermore, the experimental results on Yale database validate that gradient faces is also insensitive to image noise and object artifacts (such as facial expressions).
Under the progress trend of the information technology period environment of deepening study curriculum reform, personalized learning in specialized education of industrial colleges has become one of ...its key contents. This paper mainly studies the necessary system design based on characteristics of genetic calculation for specialized education in industrial colleges under industry-education integration. This paper first introduces the principle of genetic algorithm. It then proceeds to introduce in detail the shortcomings of The advantage of this calculation method is that the standard calculation tendency is unable to move forward in an area extremes, the iteration is relatively slow, and the low accuracy when dealing with optimization problems. Then the design and construction ideas of the personalized platform and the database design from Learners, educators (teachers), and administrators are compared by experimentally analyzing the data diversity and convergence of the three algorithms on the database. Experimentally, the diversity of the self-adaptive genetic algorithm is maintained at 0.8, and the diversity, iteration time, and convergence standard are better compared with the comparison subject. Using a self-adaptive genetic algorithm to evaluate and rank learners’ personality differences and to provide and recommend suitable learning methods for learners helps develop education and improve teaching quality and has great historical significance for China’s development and international status.
In natural photosynthesis, the architecture of multiproteins integrates more chromophores than redox centers and simultaneously creates a well‐controlled environment around the active site. Herein, ...we demonstrate that these features can be emulated in a prototype hydrogen‐bonded organic framework (HOF) through simply varying the proportion of metalated porphyrin in the structure. Further studies demonstrate that changing the metalloporphyrin content not only realizes a fine tuning of the photosensitizer/catalyst ratio, but also alters the microenvironment surrounding the active site and the charge separation efficiency. As a result, the obtained material achieves the challenging overall CO2 reduction with a high HCOOH production rate (29.8 μmol g−1 h−1, scavenger free), standing out from existing competitors. This work unveils that the degree of metalation is vital to the catalytic activity of the porphryinic framework, presenting as a new strategy to optimize the performance of heterogeneous catalysts.
A biomimetic catalyst for efficient overall CO2 photoreduction was developed through self‐assembling porphyrins into a hydrogen‐bonded organic framework. The combination of more photosensitizers than redox centers in the structure allows for not only the adequate photon input and efficient use of photogenerated charge, but noticeable changes to the microenvironment surrounding active sites.
Visible‐light‐driven H2 production from pure water is highly promising but unfortunately inefficient. Herein, for the first time, we report the realization of pure‐water‐splitting H2 production under ...visible‐light irradiation via single‐component CdS without any cocatalysts, employing a piezoelectric‐photocatalysis strategy. Wurtzite CdS nanorod arrays that combine piezoelectric and visible‐light photocatalytic properties was in‐situ assembled on FTO substrates to harvest both solar energy and ultrasonic vibration energy in water. The ultrasound‐induced piezoelectric field in CdS drives the separation of photo‐generated charge carriers, leading to more facile water‐splitting for H2 evolution than that under visible‐light irradiation alone. The CdS nanorod arrays achieves a high H2 production rate of 20 μL.h−1 under optimized coupling field, which is much higher than that of unsupported samples. This work demonstrates the capability of piezoelectric photocatalysts to simultaneously convert visible light energy and acoustic energy into hydrogen energy, which may break a new ground for the design of energy‐conversion materials towards harvesting discrete ambient energy in urban environment.
Getting down to light and sound: Visible‐light H2 evolution from pure water is realized by CdS photocatalyst with the indispensable assistance of ultrasonic vibration. A new fundamental mechanism of synergetic photo‐sono‐catalysis is proposed and proved, that is, photo‐generated electrons and holes are efficiently separated and reversely enriched on the surface of CdS nanorods by the ultrasound‐induced internal piezoelectric field.
•Two distinct microwave soil moisture disaggregation approaches have been used.•The disaggregated soil moisture in both of these approaches has been compared to in situ observations.•The accuracy of ...the soil moisture disaggregation methods varies through years and seasons.
Soil moisture at high spatial resolution is required for various land processes related studies. However, currently the resolution of passive microwave retrieved soil moisture is low – around 25km. To solve this problem, a soil moisture disaggregation algorithm based on thermal inertia relationship between daily temperature change and average soil moisture modulated by vegetation conditions has been formulated. This algorithm was applied to the AMSR-E (Advanced Microwave Scanning Radiometer – Earth Observing System) as well as SMOS (Soil Moisture and Ocean Salinity satellite) to produce the 1km downscaled soil moisture over the Little Washita Watershed in Oklahoma for the growing season in 2010 and 2011.The disaggregated soil moisture has been compared to in situ observations. The results of this approach are very encouraging.
An acidic exopolysaccharide (EPS) designated as EPS103 was isolated, purified and characterized from Lactobacillus plantarum JLAU103. EPS103 had a relatively lower molecular weight of 12.4 KDa and ...was consisted of arabinose, rhamnose, fucose, xylose, mannose, fructose, galactose, and glucose in an approximate molar ratio of 4.05: 6.04: 6.29: 5.22: 1.47: 5.21: 2.24: 1.83. A specific spectrogram of acidic polysaccharide was obtained by FT-IR analysis, and both α- and β-type configurations were presented in EPS103 based on the nuclear magnetic resonance spectroscopy. Microstructural analysis of EPS103 demonstrated a smooth and glittering cube structure, and presence of many homogeneous rod-shaped lumps. Comprehensive study of in vitro antioxidant activity indicated that EPS103 possess strong scavenging abilities against hydroxyl, ABTS, and DPPH radicals with the maximum of 80.4%, 65.5%, and 60.5%, respectively, at 10 mg/mL concentration. Furthermore, EPS103 also showed strong ferrous ions chelating activity and oxygen radical absorbance capacity. These results together indicated that the EPS103 isolated from L. plantarum JLAU103 has great potential for use as a natural antioxidant or functional additive in foods industry.
Display omitted
•An acidic exopolysaccharide from Lactobacillus plantarum JLAU103 (EPS103) was isolated and purified.•Functional groups of EPS103 were identified using FT-IR and NMR (1H and 13C).•SEM and AFM revealed the EPS103 microcosmic morphology.•EPS103 had strong in vitro antioxidant activity.
Under topological guidance, the self‐assembly process based on a tetratopic porphyrin synthon results in a hydrogen‐bonded organic framework (HOF) with the predicted square layers topology (sql) but ...unsatisfied stability. Strikingly, simply introducing a transition metal in the porphyrin center does not change the network topology but drastically causes noticeable change on noncovalent interaction, orbital overlap, and molecular geometry, therefore ultimately giving rise to a series of metalloporphyrinic HOFs with high surface area, and excellent stability (intact after being soaked in boiling water, concentrated HCl, and heated to 270 °C). On integrating both photosensitizers and catalytic sites into robust backbones, this series of HOFs can effectively catalyze the photoreduction of CO2 to CO, and their catalytic performances greatly depend on the chelated metal species in the porphyrin centers. This work enriches the library of stable functional HOFs and expands their applications in photocatalytic CO2 reduction.
Crystallographic and computational studies on a series of porphyrinic hydrogen‐bonded organic frameworks (HOFs) reveal that metallization of porphyrin centers greatly alters the orbital overlap of the adjacent porphyrin, the geometry of the molecule/layer, and the strength of noncovalent interactions. Therefore, metalloporphyrin HOFs exhibit much higher stability, surface area, and catalytic activity than metal‐free porphyrinic HOFs.
The development of high-efficient photocatalysts plays an important role in the sustainable utilization of solar energy. Hollow nanostructured photocatalysts are vital for solar light utilization and ...charge carrier separation in photocatalytic processes. Therefore, the construction of hollow semiconductor photocatalysts is a promising strategy for preparing novel high-efficient photocatalysts. This paper reviews common hollow semiconductor nanomaterials, such as oxides, sulfides, nitrides, C3N4, MOFs, and their composite photocatalysts. The characteristics of hollow-structure photocatalysts, the application of solar energy conversion, and their understanding of the photocatalytic mechanism are also reviewed. In addition, future challenges will be focused on designing and majorizing broadband response hollow-structure photocatalysts to further enhance solar energy conversion. Hollow semiconductor photocatalysts will have potential applications in the natural environment, and these synthesized strategies can also provide new possibilities for synthesizing other high-performance semiconductor photocatalysts.
Hollow semiconductor photocatalytic nanomaterials including oxides, sulfides, nitrides, g-C3N4, MOFs and their composites are reviewed. The characteristics, formation, applications for solar energy conversion and the deep understanding of photocatalytic mechanism for hollow semiconductor photocatalysts are also reviewed, which may provide new insights for fabricating high-performance hollow photocatalysts. Display omitted
•This review summarizes hollow photocatalysts including oxides, sulfides, nitrides, C3N4, MOF.•The effects of different modification methods of hollow photocatalysts are reviewed.•The recent development for preparing hollow semiconductor photocatalysts is summarized.•The application of hollow photocatalysts for solar energy conversion is reviewed.•The potential directions for hollow photocatalysts are proposed.
PDF