Human activities have shaped large-scale distributions of many species, driving both range contractions and expansions. Species differ naturally in range size, with small-range species concentrated ...in particular geographic areas and potentially deviating ecologically from widespread species. Hence, species’ responses to human activities may be influenced by their geographic range sizes, but if and how this happens are poorly understood. Here, we use a comprehensive distribution database and species distribution modeling to examine if and how human activities have affected the extent to which 9,701 vascular plants fill their climatic potential ranges in China. We find that narrow-ranged species have lower range filling and widespread species have higher range filling in the human-dominated southeastern part of China, compared with their counterparts distributed in the less human-influenced northwestern part. Variations in range filling across species and space are strongly associated with indicators of human activities (human population density, human footprint, and proportion of cropland) even after controlling for alternative drivers. Importantly, narrow-ranged and widespread species show negative and positive range-filling relationships to these human indicators, respectively. Our results illustrate that floras risk biotic homogenization as a consequence of anthropogenic activities, with narrow-ranged species becoming replaced by widespread species. Because narrow-ranged species are more numerous than widespread species in nature, negative impacts of human activities will be prevalent. Our findings highlight the importance of establishing more protected areas and zones of reduced human activities to safeguard the rich flora of China.
A copper‐catalyzed α,β‐regioselective (2+4) cycloaddition of propargylic esters with o‐hydroxyphenyl substituted secondary phosphine oxides (SPOs) was established, which afforded a series of ...phosphorus‐containing six‐membered heterocycles in high yields. This reaction represents the first α,β‐regioselective (2+n) cycloaddition of propargylic esters via the intermediates of copper‐allenylidenes, which will enrich the chemistry of propargylic esters and copper‐allenylidenes. Moreover, this work also represents the first application of o‐hydroxyphenyl substituted SPOs as 1,4‐dinucleophiles in (2+4) cycloadditions, which provides a useful protocol for the synthesis of phosphorus‐containing six‐membered heterocycles with potential bioactivity.
A copper‐catalyzed α,β‐regioselective (2+4) cycloaddition of propargylic esters with o‐hydroxyphenyl substituted secondary phosphine oxides (SPOs) was established, which afforded phosphorus‐containing six‐membered heterocycles in high yields. This reaction not only represents the first α,β‐regioselective (2+n) cycloaddition of propargylic esters via the intermediates of copper‐allenylidenes, but also represents the first application of o‐hydroxyphenyl substituted SPOs as 1,4‐dinucleophiles in (2+4) cycloadditions.
The symptoms of vaginal candidiasis exacerbate in the second half of the menstrual cycle in premenopausal women when the serum estradiol level is elevated. Estradiol has been shown to inhibit Th17 ...differentiation and production of antifungal IL-17 cytokines. However, little is known about the mechanisms. In the present study, we used mouse splenocytes and found that estradiol inhibited Th17 differentiation through downregulation of Rorγt mRNA and protein expression. Estradiol activated estrogen receptor (ER)α to recruit repressor of estrogen receptor activity (REA) and form the ERα/REA complex. This complex bound to three estrogen response element (ERE) half-sites on the Rorγt promoter region to suppress Rorγt expression. Estradiol induced Rea mRNA and protein expression in mouse splenocytes. Using Rea small interfering RNA to knock down Rea expression enhanced Rorγt expression and Th17 differentiation. Alternatively, histone deacetylase 1 and 2 bound to the three ERE half-sites, independent of estradiol. Histone deacetylase inhibitor MS-275 dose- and time-dependently increased Rorγt expression and subsequently enhanced Th17 differentiation. In 15 healthy premenopausal women, high serum estradiol levels are correlated with low RORγT mRNA levels and high REA mRNA levels in the vaginal lavage. These results demonstrate that estradiol upregulates REA expression and recruits REA via ERα to the EREs on the RORγT promoter region, thus inhibiting RORγT expression and Th17 differentiation. This study suggests that the estradiol/ERα/REA axis may be a feasible target in the management of recurrent vaginal candidiasis.
Lactate, the main contributor to the acidic tumor microenvironment, not only promotes the proliferation of tumor cells, but also closely relates to tumor invasion and metastasis. Here, a tumor ...targeting nanoplatform, designated as Me&Flu@MSN@MnO
-FA, was fabricated for effective tumor suppression and anti-metastasis by interfering with lactate metabolism of tumor cells. Metformin (Me) and fluvastatin sodium (Flu) were incorporated into MnO
-coated mesoporous silicon nanoparticles (MSNs), the synergism between Me and Flu can modulate the pyruvate metabolic pathway to produce more lactate, and concurrently inhibit lactate efflux to induce intracellular acidosis to kill tumor cells. As a result of the restricted lactate efflux, the extracellular lactate concentration is reduced, and the ability of the tumor cells to migrate is also weakened. This ingenious strategy based on Me&Flu@MSN@MnO
-FA showed an obvious inhibitory effect on tumor growth and resistance to metastasis.
Long-term degradation of black soil has led to reductions in soil fertility and ecological service functions, which have seriously threatened national food security and regional ecological security. ...This study is motivated by the UN’s Sustainable Development Goal (SDG) 2—Zero Hunger, specifically, SDG 2.4 Sustainable Food Production Systems. The aim was to monitor the soil organic matter (SOM) content of black soil and its dynamics via hyperspectral remote sensing inversion. This is of great significance to the effective utilization and sustainable development of black soil resources. Taking the typical black soil area of Northeast China as an example, the hyperspectral data of ground features were compared with SOM contents measured in soil samples to correlate SOM with spectral features. Based on their quantitative relationship, a dynamic fitness inertia weighted particle swarm optimization (DPSO) algorithm is proposed, which balances the global and local search abilities of a particle swarm optimization algorithm. The DPSO algorithm is applied to the parameter adjustment of an artificial neural network (BPNN), which is used instead of a traditional error back propagation algorithm, to build a DPSO-BPNN model. Then a global optimal analytical expression of hyperspectral inversion is obtained to improve the generalization ability and stability of the remote sensing quantitative inversion model. The results show that DPSO-BPNN model is more stable and accurate than existing models, such as multiple stepwise regression, partial least squares, and BP neural network models (adjust complex coefficient of determination = 0.89, root mean square error = 1.58, relative recent deviation = 2.93). The results of DPSO-BPNN inversion are basically consistent with the trend in SOM contents measured during surface geochemical exploration. As such, this study provides a basis for hyperspectral remote sensing inversion and monitoring of the SOM contents in black soil.
Regarding the issue of intense mining pressure appearing in the underlying gateway below the remaining coal pillar in the close‐distance coal seam (the remaining coal pillar is perpendicular to the ...underlying section coal pillar), 401 working face is used as the engineering background. Field measurements, laboratory experiments, numerical simulations, and engineering verification techniques are used to study the abutment pressure's evolution properties and the plastic zone's propagation laws before and after the underlying coal seam roadway experienced the mining impact. The conclusions are as follows: ① The maximum plastic area on the two sides and the roof of the roadway underlying the gob are up to 2 and 1.5 m, whereas the maximum plastic area on the two sides and the roof of the roadway underlying the remaining coal pillar are up to 5 and 4.5 m, respectively. Moreover, the plastic area extends along the two sides, and the section coal pillar is completely broken when the working face is mined below the remaining coal pillar. ② The stress increase coefficient K in the overlap area of the remaining coal pillar and the underlying section coal pillar reaches 3.4 when the mining face penetrates the underlying remaining coal pillar and the advance abutment pressure is overlaid with the concentrated stress of the coal pillar. ③ When the underlying working face is mined to 4, −2, −8, and −14 m away from the remaining coal pillar, the damage range of the roadway 5–10 m ahead increases in turn. At the same time, the maximum plastic area of the roof passes through the plastic area of the upper coal seam floor. Therefore, the underlying and transition areas on both sides of the remaining coal pillar are divided into Area I (15 m) → Area II (the most complicated area to control under the remaining coal pillar, 20 m) → Area III (25 m) according to the width. Furthermore, the divisional differentiated combined control technology of channel steel truss anchor cable with joint double‐way locking control function of roof and coal pillar in Areas I and III, while channel steel truss anchor cable with joint double‐way locking control function of roof and side + high resistance integral door‐type support is proposed in Area II. Field engineering practice shows that the deformation of the roadway surrounding rock can be controlled within 210 mm after adopting the above divisional combined control technology. Finally, the mining operation can safely and efficiently pass through the remaining coal pillar. The research results have important reference values for surrounding rock control of mining roadways in the overlapping area of similar “+”‐type cross‐working face.
Regarding the issue of intense mining pressure appearing in the underlying gateway below the remaining coal pillar in the close‐distance coal seam (the remaining coal pillar is perpendicular to the underlying section coal pillar), 4#–401 working face is used as the engineering background. The evolution characteristics of the abutment pressure and the expansion regulation of the plastic zone before and after the underlying coal seam roadway experienced the mining impact are analyzed using field measurements, laboratory tests, numerical simulations, and engineering verification methods.
As the output power of photovoltaic (PV) array changes with the change of external environment and load, the maximum power point tracking (MPPT) technology is needed to bring the efficiency of PV ...device into full play. In this paper, the chaos search theory is first applied on the MPPT technology of PV system; the chaos search algorithm based on dual carrier increases the adequacy of chaos search and overcomes the blindness of traditional chaos search, thus improves the search efficiency and solves the problem of multiple MPP under partially shadowing conditions. Comparative tests show that the proposed method can track the step response quickly and accurately; at the same time get better optimization result. Simulation and experimental results showed the effectiveness and good performance of the proposed method.
To investigate the role of periosteum on the treatment of buccal dehiscence defects comparing with collagen membrane in canine model. Bilateral dehiscence-type defects at the buccal side on the ...distal root of the lower 3rd/4th premolars were created in six beagle dogs with a total of 24 defects and assigned into three groups: Group A: blood clot in an untreated defect; Group B: deproteinized bovine bone material (DBBM) covered with an absorbable membrane; Group C: DBBM covered with the periosteum. The structural parameters for trabecular architecture and vertical bone regeneration were evaluated. Histological and histomorphometric evaluation were carried out to observe new bone formation and mineralization in the graft site. Immunohistochemical analysis was performed to identify the expression of osteopontin (OPN) and osteocalcin (OCN) at postoperative 3 months. Group C achieved greater vertical alveolar bone gain than that of group A and group B. The periosteum-covered group showed significantly greater new bone formation and accelerated mineralization. The greater immunolabeling for OPN and OCN was observed in group C than in group A. Periosteal coverage has explicit advantages over collagen membranes for the quality and quantity of new bone regeneration in dehiscence defects repairing.
Separating geochemical anomalies from background values is crucial for the processing of geochemical data. In the present study, a workflow for identifying geochemical anomalies was constructed by ...using the direct sampling algorithm of multi-point geostatistics, the maximum entropy model, and local singularity analysis. The smoothing effect and the uncertainty of the unsampled point value in the traditional interpolation method were taken into consideration in this workflow. Based on the statistic of singular exponential distribution of each element with equal probability, the geochemical anomaly probability distribution of each element was obtained (Ag、Cd、Cu、Pb、Zn). Based on the five anomaly probability distributions, the maximum entropy model was used to establish a comprehensive perspective of geochemical anomaly uncertainty evaluation. The validity of the method was verified by analyzing geochemical data of stream sediment samples from the Mila Mountain region in Tibet. The results showed that the prospectivity map of copper deposits generated by the maximum entropy model can effectively link the probability of multivariate geochemical anomalies with the known positions of copper deposits and greatly increase the precision of the potential exploration areas for copper deposits.
•Geochemical anomalies identified by direct sampling algorithm and maximum entropy model.•Direct sampling algorithm tackles smoothing effect and uncertainty of missing points.•Maximum entropy model effective in fusing multiple geochemical anomalies information.
Diet analysis of potential small mammals pest species is important for understanding feeding ecology and evaluating their impact on crops and stored foods. Chinese mole shrew (Anourosorex squamipes), ...distributed in Southwest China, has previously been reported as a farmland pest. Effective population management of this species requires a better understanding of its diet, which can be difficult to determine with high taxonomic resolution using conventional microhistological methods. In this study, we used two DNA metabarcoding assays to identify 38 animal species and 65 plant genera from shrew stomach contents, which suggest that A. squamipes is an omnivorous generalist. Earthworms are the most prevalent (>90%) and abundant (>80%) food items in the diverse diet of A. squamipes. Species of the Fabaceae (frequency of occurrence FO: 88%; such as peanuts) and Poaceae (FO: 71%; such as rice) families were the most common plant foods identified in the diet of A. squamipes. Additionally, we found a seasonal decrease in the diversity and abundance of invertebrate foods from spring and summer to winter. Chinese mole shrew has a diverse and flexible diet throughout the year to adapt to seasonal variations in food availability, contributing to its survival even when food resources are limited. This study provides a higher resolution identification of the diet of A. squamipes than has been previously described and is valuable for understanding shrew feeding ecology as well as evaluating possible species impacts on crops.
Little is known about the invertebrate prey species and plants (especially crops at the species level) consumed by A. squamipes, which prevents understanding of their feeding ecology and thus impedes effective pest control. The Chinese mole shrew tends to be a generalized predator of a diverse array of invertebrates (e.g., earthworm) and plants (e.g., crops). Based on molecular techniques, diverse plant materials at the species level were identified with frequent observation of several important crops (e.g., rice and peanuts), indicating that A. squamipes could cause serious damage to crops or stored grains. Characterizing the diet of A. squamipes may have implications for the evaluating crop impacts and control of this shrew pest.
PDF
