In theory, changes in the amount of rainfall can change plant biomass allocation and subsequently influence coupled plant-soil microbial processes. However, testing patterns of combined responses of ...plants and soils remains a knowledge gap for terrestrial ecosystems. We carried out a comprehensive review of the available literature and conducted a meta-analysis to explore combined plant and soil microbial responses in grasslands exposed to experimental precipitation changes. We measured the effects of experimental precipitation changes on plant biomass, biomass allocation, and soil microbial biomass and tested for trade-offs between plant and soil responses to altered precipitation. We found that aboveground and belowground plant biomass responded asynchronically to precipitation changes, thereby leading to shifts in plant biomass allocation. Belowground plant biomass did not change under precipitation changes, but aboveground plant biomass decreased in precipitation reduction and increased in precipitation addition. There was a trade-off between responses of aboveground plant biomass and belowground plant biomass to precipitation reduction, but correlation wasn't found for precipitation addition. Microbial biomass carbon (C) did not change under the treatments of precipitation reduction. Increased root allocation may buffer drought stress for soil microbes through root exudations and neutralize microbial responses to precipitation reduction. However, precipitation addition increased microbial biomass C, potentially reflecting the removal of water limitation for soil microbial growth. We found that there were positive correlations between responses of aboveground plant biomass and microbial biomass C to precipitation addition, indicating that increased shoot growth probably promoted microbial responses via litter inputs. In sum, our study suggested that aboveground, belowground plant biomass and soil microbial biomass can respond asynchronically to precipitation changes, and emphasizes that testing the plant-soil system as a whole is necessary for forecasting the effects of precipitation changes on grassland systems.
The effects of low voltage electrostatic field thawing (LVEFT) on the changes in physicochemical properties of myofibrillar proteins and the quality of thawed beef were investigated. Results showed ...that by applying LVEFT, thawing process was shortened by 42%. LVEFT significantly reduced thawing loss and shear force of the thawed beef (P < 0.05) by protecting muscle microstructures. Results of low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) confirmed the reduction of thawing loss under LVEFT. Fourier transform infrared (FTIR) result suggested that the denaturated myofibrillar proteins (freezing-induced) would renaturate with thawing time, and the results of protein surface hydrophobicity and solubility were corresponded with it. The bonding capacity between protein and water (ionic bonds and hydrogen bonds) also increased with thawing time. It is demonstrated that LVEFT could effectively reduce quality loss of the beef and accelerate the renaturation of protein during thawing process while significantly shortening the thawing time (P < 0.05). These results evidenced a potential application of LVEFT method for meat thawing.
•Low voltage electrostatic field thawing (LVEFT) effectively maintained beef quality while shortening thawing time.•The freezing-induced denaturated myofibrillar protein renaturates with thawing time.•Results evidenced a potential application of LVEFT in meat thawing.
Acid mine drainage (AMD) contains high concentrations of heavy metals and sulfates with strong acidity. AMD exists in several major coal-producing countries such as China, the United States, Canada, ...etc., and it poses significant threaten to the environment and human health owing to it exists in nature for a long time and continues to cause harm after mining. In China, about 3.5 billion tons of AMD was produced annually and their negative effects on the ecological environment and human health in mining area cannot be ignored. Herein, the formation mechanism and environmental impact of AMD are discussed thoroughly. Additionally, the principles and applications of several AMD treatment technologies are discussed in detail and the limitations of the practical application of AMD in China are summarized. On this basis, the current status and importance of the resource utilization of AMD are further discussed. Finally, the future direction of AMD treatment is proposed. In principle, this review will provide useful implications in guiding the treatment and resource utilization of AMD.
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•Several acid mine drainage (AMD) treatment technologies are discussed in detail.•The limitations of the practical application of AMD in China are summarized.•New material development and waste utilization is one of the future directions.•Resource utilization offers the possibility of sustainable management of AMD.•The integrated use of integrated processes is a promising approach to AMD treatment.
Chondroitin sulfate (CS) is a natural macromolecule polysaccharide that is extensively distributed in a wide variety of organisms. CS is of great interest to researchers due to its many in vitro and ...in vivo functions. CS production derives from a diverse number of sources, including but not limited to extraction from various animals or fish, bio-synthesis, and fermentation, and its purity and homogeneity can vary greatly. The structural diversity of CS with respect to sulfation and saccharide content endows this molecule with distinct complexity, allowing for functional modification. These multiple functions contribute to the application of CS in medicines, biomaterials, and functional foods. In this article, we discuss the preparation of CS from different sources, the structure of various forms of CS, and its binding to other relevant molecules. Moreover, for the creation of this article, the functions and applications of CS were reviewed, with an emphasis on drug discovery, hydrogel formation, delivery systems, and food supplements. We conclude that analyzing some perspectives on structural modifications and preparation methods could potentially influence future applications of CS in medical and biomaterial research.
As one common form of gas existing in aqueous environment, gas bubbles have attracted considerable worldwide attention, owing to their promising applications in industrial production and daily life, ...such as pressure sensors, the recovery of valuable minerals from ores, aeration process, and water treatment. Usually, the behaviors of gas bubbles in aqueous environment are mainly dominated by buoyancy force. It drives the gas bubbles out of aqueous medium rapidly, which is unfavorable in various processes, especially in wastewater treatment. In this paper, various types of superhydrophobic poly(methyl methacrylate) (PMMA) sheets are facilely fabricated, such as five‐pointed star, triangle, circular, and ellipse. Compared with other shapes of superhydrophobic PMMA sheets, the prepared superhydrophobic PMMA circular sheet is capable of efficiently adhering gas bubbles and subsequently elongating their retention time in an aqueous environment. Furthermore, superhydrophobic PMMA circular sheet arrays are prepared, which can greatly improve the degradation efficiency of methyl blue by ozone (O3). The investigations indicate that the present approach will find wild applications in bubble‐related fields and provide people with inspirations to develop efficient methods to manipulate gas bubbles in aqueous environment.
Utilizing laser cutting and superhydrophobic surface coating, superhydrophobic poly(methyl methacrylate) (PMMA) circular sheets (SPCS) are facilely fabricated. The prepared SPCS can elongate the retention time and enlarge the contact area of bubbles in water. Furthermore, integrating the superhydrophobic PMMA circular sheet arrays with O3 improves the degradation efficiency of dye pollutants by O3.
The probability of inter-crystal scattering (ICS) events for 511 keV gamma rays in all current scintillation crystals is high and the ICS events degrade the spatial resolution of PET scanners. In ...this work, Monte Carlo simulations were performed to study the effects of ICS events on the sensitivity and spatial resolution of PET detectors. LaBr
, LYSO, and PWO that represent scintillation crystals of low, medium and high density, respectively, were used. For a point source placed in the middle of two scintillation detectors of 50 × 50 × 20 mm
and a lower energy threshold (LET) of 350 keV, the probabilities that at least one gamma ray undergoes ICS are 94%, 84% and 76% for LaBr
, LYSO, and PWO, respectively. The ICS events still provide useful spatial information. The full width at half maximum (FWHM), the full width at tenth maximum (FWTM) and the mean absolute error (MAE) of the curve of the mispositioning of a point source caused by ICS events are 0.45, 3.0 and 0.9 mm if the most popular PET scintillator LYSO is used. The MAE is smaller than the spatial resolution of most current PET scanners. The effect of ICS increases as the detector LET increases, scintillator density decreases, and crystal size decreases. The intrinsic spatial resolutions of a pair of LYSO detectors were calculated using curves of the coincidence counts between one column of the crystals in the two detectors and the sum of the coincidence counts between two opposite crystals of the columns in the two detectors that are in line with the point source changing with the source positions. The latter method removes almost all of ICS events. The FWHM (FWTM) intrinsic spatial resolutions obtained by the two methods are 0.40 (2.0) mm and 0.33 (0.8) mm if the crystal size is 0.5 mm, and are 0.8 (3.0) and 0.68 (1.5) mm if the crystal size is 1.0 mm. ICS events have much bigger contributions to the FWTM rather than the FWHM of the intrinsic spatial resolution of PET detectors. The spatial resolution of a PET scanner can still be improved by decreasing the crystal size to as small as 0.5 mm.
The cell transformation from green motile cells to non-motile cells and astaxanthin accumulation can be induced in the green alga
cultured outdoors. In the initial 3 d of incubation (cell ...transformation phase), light absorption and photosynthetic electron transport became more efficient. After five days of incubation (astaxanthin accumulation phase), the light absorption per active reaction center (ABS/RC) increased, but the efficiency of electron transport (
) and the quantum yield of electron transport (
) decreased with increased time, indicating that the capacity of photosynthetic energy utilization decreased significantly during astaxanthin accumulation, leading to an imbalance between photosynthetic light absorption and energy utilization. It would inevitably aggravate photoinhibition under high light, e.g., at midday. However, the level of photoinhibition in
decreased as the incubation time increased, which is reflected by the fact that
/
determined at midday decreased significantly in the initial 3 d of incubation, but was affected very little after seven days of incubation, compared with that determined at predawn. This might be because the non-photochemical quenching, plastid terminal oxidase, photosystem I cyclic electron transport, defensive enzymes and the accumulated astaxanthin can protect cells against photoinhibition.
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•OBS was detected in all 11 tissues and intestinal contents.•The liver exhibited the highest OBS level, followed by the small intestine, lung, and kidney.•Gender of mice will affect ...tissue distribution of OBS.•Different distribution characteristics were observed for three isomers of OBS.
Environmental risks caused by emerging per- and polyfluoroalkyl substances (PFASs) have attracted increasing attention. As an important substitute for perfluorooctane sulfonate (PFOS), sodium p-perfluorous nonenoxybenzene sulfonate (OBS) is widely used as a firefighting foam additive and oil recovery agent in China. This study reported the tissue distribution of OBS in KM mice that were administered a dose of OBS at 10 µg/day via daily oral gavage for 7, 14, or 28 days. During exposure, gender-based differences were observed in body weight changes and tissue distribution of OBS. Liver exhibited the highest concentrations (males: 12.57 ± 1.80 µg/g; females: 11.80 ± 5.32 µg/g) and tissue/blood ratios and contributed more than 50% to the whole-body burden of OBS in both male and female mice, showing its ability to enrich PFASs. Furthermore, there were certain differences in the distribution characteristics of the three OBS isomers. Based on its bioaccumulation potential and widespread use, further studies are required on the human exposure risks of OBS.
Aimed to corroborate students' and faculty's experiences with e-learning during the current pandemic.
A cross-sectional study was conducted from February to June 2020. Seven surveys were distributed ...electronically to all undergraduate students and the faculty (4 to students and 3 to teachers) at the Southern Medical University (China). Descriptive statistics and t-tests were used to analyze the data. Statistical significance was set at p < .05.
Most students had some exposure to e-learning prior to the all e-learning regiment, contrasted with close to 90% of teachers having no or very limited experience. Students' perceptions of the most helpful e-learning activities did not change significantly overall (Week 3 vs. Week 9). Approaching 60% of students (Week 9) did find online discussion/Q&A/forum helpful, an increase from less than 30% (Week 3). Among teachers, gaps emerged (Week 9) between e-teaching activities used and their perceived effectiveness. Despite pre-recorded lectures being the most frequently used method, the least gap was associated with live-stream lectures-the least used. Over time, teacher's perceived effectiveness of e-teaching vs. in-person teaching did not differ significantly overall. When the results among students (Week 7) and teachers (Week 9) were corroborated, a slightly higher percentage of teachers viewed online teaching to be less effective than in-person teaching and a slightly higher percentage of teachers viewed online teaching as far less effective. For preferred learning modes after the resumption of in-person learning, students' preferences did not differ significantly overall (Week 3 vs. week 9). Surveys conducted in Week 9 found that a slightly higher percentage of students (~ 70%) than teachers (~ 60%) preferred some forms of hybrid learning and a lower percentage of students preferred face-to-face learning only. Approximately three quarters of teachers responded that at least 50% of course materials could be mastered by students on their own.
Overall, the perceived effectiveness of e-learning among students and teachers has not changed significantly over time. Nor have students' preferences shifted significantly for various learning modes after the in-person learning resumed. However, informative directional trends have emerged. Our research illustrates empirically the need to corroborate students' and instructors' experiences over time to inform more holistic improvements of e-learning.
In order to improve the strength of polyvinyl alcohol (PVA)/xylan composite films and endow them with ultraviolet (UV) shielding ability, TiO₂-KH550 nanoparticles was synthesized and added into the ...PVA/xylan matrix. The TiO₂-KH550 nanoparticle dispersed well in the 0.04% sodium hexametaphosphate (SHMP) solution under ultrasonic and stirring treatments. Investigations on the properties of the films showed that TiO₂-KH550 had the positive impact on improving the strength, moisture, and oxygen barrier properties of the composite films. The maximum tensile strength (27.3 MPa), the minimum water vapor permeability (2.75 × 10
g·m
·s
·Pa
), and oxygen permeability (4.013 cm³·m
·24 h
·0.1MPa
) were obtained under the addition of 1.5% TiO₂-KH550. The tensile strength of TiO₂-KH550 reinforced composite film was increased by 70% than that of the pure PVA/xylan composite film, and the water vapor and oxygen permeability were decreased by 31% and 41%, respectively. Moreover, the UV transmittance of the film at the wavelength of 400 nm was almost zero when adding ≈1.5~2.5% (weight ratio, based on the total weight of PVA and xylan) of TiO₂-KH550, which indicated the PVA/xylan composite films were endowed with an excellent UV light shielding ability.
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