Premise of the Study
The growth limitation hypothesis (GLH) and carbon limitation hypothesis (CLH) are two dominant explanations for treeline formation. The GLH proposes that low temperature drives ...the treeline through constraining C sinks more than C sources, and it predicts that non‐structural carbohydrate (NSC) levels are static or increase with elevation. Although the GLH has received strong support globally for evergreen treelines, there is still no consensus for deciduous treelines, which experience great asynchrony between supply and demand throughout the year.
Methods
We investigated growth and the growing‐season C dynamics in a common deciduous species, Erman's birch (Betula ermanii), along an elevational gradient from the closed forest to the treeline on Changbai Mountain, Northeast China. Samples were collected from developing organs (leaves and twigs) and main storage organs (stems and roots) for NSC analysis.
Key Results
Tree growth decreased with increasing elevation, and NSC concentrations differed significantly among elevations, organs, and sampling times. In particular, NSC levels varied slightly during the growing season in leaves, peaked in the middle of the growing season in twigs and stems, and increased continuously throughout the growing season in roots. NSCs also tended to increase or vary slightly in developing organs but decreased significantly in mature organs with increasing elevation.
Conclusions
The decrease in NSCs with elevation in main storage organs indicates support for the CLH, while the increasing or static trends in new developing organs indicate support for the GLH. Our results suggest that the growth limitation theory may be less applicable to deciduous species' growth than to that of evergreen species.
A hollow mesoporous manganese dioxide-based (H-MnO2) multifunctional nanoplatform, H-MnO2 @AFIPB@PDA@Ru-NO@FA (MAPRF NPs), was prepared for synergistic cancer treatment, in which a histone ...deacetylase inhibitor AFIPB was loaded in its hollow cavity and a ruthenium nitrosyl donor (Ru-NO) and a folic acid (FA) targeting group were covalently decorated on its covered polydopamine (PDA) layer. The MAPRF NPs showed tumor microenvironment (TME)-responsive properties of depletion of glutathione (GSH) to disrupt the antioxidant defense system and on-demand drug delivery. And the released Mn2+ further catalyzed the decomposition of endogenous H2O2 to produce highly toxic hydroxyl radicals (·OH) for enhanced chemodynamic therapy (CDT). Furthermore, upon 808 nm light irradiation MAPRF NPs exhibited controlled nitric oxide (NO) delivery and simultaneously produced significant photothermal effect. Consequently, MAPRF NPs showed high mortality toward cancer cells in the presence of 808 nm light irradiation. This work provides a paradigm of multimodal synergistic therapy that combines NO-based gas therapy with TME modulation for efficient antitumor therapy.
A novel mesoporous MnO2-based multifunctional nanoplatform exhibited near-infrared light-controlled nitric oxide delivery, tumor microenvironment (TME)-responsive release of a histone deacetylase inhibitor and TME modulation for efficient multimodal synergistic antitumor therapy. Display omitted
•A hollow mesoporous MnO2-based multifunctional NO-releasing nanoplatform was prepared.•Tumor microenvironment-responsive of GSH depletion and hydroxyl radical production.•Controlled NO delivery and photothermal effect was achieved upon 808 nm light irradiation.•It showed high mortality toward cancer cells under 808 nm light irradiation.•Synergistic multimodal therapies were attributed to the enhanced antitumor efficiency.
In this work, the hydrophobic small molecule NF-κB inhibitor celastrol was loaded into poly(ethylene glycol)-b-poly(propylene sulfide) (PEG-b-PPS) micelles. PEG-b-PPS micelles demonstrated high ...loading efficiency, low polydispersity, and no morphological changes upon loading with celastrol. Encapsulation of celastrol within these nanocarriers significantly reduced cytotoxicity compared to free celastrol, while simultaneously expanding the lower concentration range for effective inhibition of NF-κB signaling by nearly 50 000-fold. Furthermore, celastrol-loaded micelles successfully reduced TNF-α secretion after LPS stimulation of RAW 264.7 cells and reduced the number of neutrophils and inflammatory monocytes within atherosclerotic plaques of ldlr-/- mice. This reduction in inflammatory cells was matched by a reduction in plaque area, suggesting that celastrol-loaded nanocarriers may serve as an anti-inflammatory treatment for atherosclerosis.
•Air warming exacerbated rice photosynthetic down-regulation during grain filling stages under elevated CO2 in T-FACE.•Air warming increasing total leaf nitrogen content did not offset the reduction ...of it under elevated CO2.•Air warming exacerbated the decrease in Rubisco content, Vcmax25,Jmax25 and N distribution in leaves under elevated CO2.•Air warming accelerated rice phenological development under elevated CO2.
Photosynthetic acclimation to elevated atmospheric CO2 concentration (CO2) accompanies decreased leaf nitrogen (N) content. Elevated air temperatures may enhance crop N nutrient content. Whether enhanced leaf N content at high temperatures relieves photosynthetic acclimation to high CO2 in rice is unclear, so we investigated the effects of elevated CO2 (eC; ambient CO2+200 μmol mol−1 CO2 and ambient temperature), elevated air temperature (eT; ambient+1 °C), and elevated temperature and CO2 together (eT + eC; ambient+1 °C +200 μmol mol−1 CO2) compared to ambient CO2 and temperature (Ambient) on photosynthetic and physiological parameters, biomass, and N accumulation and distribution throughout rice grain filling stages in 2015 and 2016. Net leaf photosynthesis (Pn) increased under eC, but the magnitude of Pn increase decreased as grain filling progressed, which was exacerbated under eT + eC. The total leaf N (TLN) content decreased by 7.1 % and increased by 4.7 % on average during the whole grain filling stage under eC and eT compared with Ambient, respectively. However, increasing TLN under elevated temperature did not offset the TLN reduction under CO2 enrichment, similar to the effects of elevated CO2 and air temperature on chlorophyll (Chl) and carotenoid (Caro) content. The percentage decrease in Rubisco content was larger under individual changes or the combined elevation of CO2 and air temperature than the percentage change in TLN under eC. Meanwhile, the maximum rate of Rubisco carboxylation at 25 °C (Vcmax25) and the maximum rate of electron transport driving RuBP regeneration at 25 °C (Jmax25) declined significantly under eT + eC. Vcmax25 had a positive relationship with Rubisco content, and Jmax25 had a positive relationship with Chl and Caro content. At the crop level, eC enhanced biomass but reduced N distribution in leaves. Furthermore, the decrease in biomass had a greater effect than the increase in TLN under eT, reducing N distribution in leaves. Photosynthetic acclimation was mainly due to the reduction in TLN and crop N distribution and the increased reduction in leaf N distribution to Rubisco under eT + eC. Therefore, an air temperature increase of approximately 1 °C exacerbated photosynthetic acclimation under eC. These results further elucidated the photosynthesis responses in rice to future climate conditions.
Zn‐air battery is a promising next‐generation energy storage device. Its performance, however, is limited by a high overpotential resulted from the slow kinetics of the cathodic oxygen reduction ...reaction (ORR). This study reports a simple strategy for preparation of a fluorine‐doped Co−N−C composite as highly efficient electrocatalyst for ORR. The C@PVI‐(TPFC)Co‐800 catalyst was prepared by pyrolysis of F‐containing Co‐corrole that was assembled on PVI‐functionalized carbon black through the axial imidazole coordination (PVI=polyvinylimidazole, TPFC=5,10,15‐triperfluorophenyl‐21H, 22H‐corrole). The C@PVI‐(TPFC)Co‐800 catalyst exhibited much more positive ORR half‐wave potential (E1/2=0.88 V vs. RHE) than its counterpart C@PVI‐(TPC)Co‐800 (E1/2=0.82 V, TPC=5,10,15‐triphenyl‐21H, 22H‐corrole) without F‐doping in 0.1 M KOH electrolyte. C@PVI‐(TPFC)Co‐800 also achieved a greater kinetic current density and enhanced durability in alkaline media. In addition, a Zn‐air battery with C@PVI‐(TPFC)Co‐800 loaded at the cathode delivered much higher peak power density (Pmax=141 mW/cm2) and open‐circuit voltage (OCV=1.45 V) over the C@PVI‐(TPC)Co‐800 counterpart (Pmax=110 mW/cm2, OCV=1.39 V) and the commercial 20 % Pt/C (Pmax=119 mW/cm2, OCV=1.42 V) as well. The promoted catalyst performance for ORR was attributed to the increased specific surface area, more defects generated, and reduced electron density distribution around the Co metal center after F‐doping.
The F‐doped Co−N−C catalyst exhibits impressively higher electrocatalytic activity and durability for oxygen reduction reaction in Zn‐air batteries than the counterpart without F‐doping and the commercial Pt/C catalyst as well.
Aims Two field microcosm experiments and ¹⁵N labeling techniques were used to investigate the effects of biochar addition on rice N nutrition and GHG emissions in an Inceptisol and an Ultisol. ...Methods Biochar N bioavailability and effect of biochar on fertilizer nitrogen-use efficiency (NUE) were studied by ¹⁵N-enriched wheat biochar (7.8803 atom% ¹⁵N) and fertilizer urea (5.0026 atom% ¹⁵N) (Experiment I). Corn biochar and corn stalks were applied at 12 Mgha⁻¹ to study their effects on GHG emissions (Experiment II). Results Biochar had no significant impact on rice production and less than 2 % of the biochar N was available to plants in the first season. Biochar addition increased soil C and N contents and decreased urea NUE. Seasonal cumulative CH₄ emissions with biochar were similar to the controls, but significantly lower than the local practice of straw amendment. N₂O emissions with biochar were similar to the control in the acidic Ultisol, but significantly higher in the slightly alkaline Inceptisol. Carbon-balance calculations found no major losses of biochar-C. Conclusion Low bio-availability of biochar N did not make a significantly impact on rice production or N nutrition during the first year. Replacement of straw amendments with biochar could decrease CH₄ emissions and increase SOC stocks.
A series of medium-sized cyclic triaxial tests were performed to investigate the permanent deformation properties of granular materials. The strain rate was then plotted against loading cycles to ...classify the permanent deformation properties of granular materials under different cyclic stress ratios (CSRs). It was found that (1) the permanent strain rate dε
/dN was linearly correlated with loading cycles N using a double-log coordinate on the condition of CSR < 60%; (2) the deformation tendency factor β, which was extracted from the linear relationship between dε
/dN and N, significantly varied with CSR and, thus, can be adopted to identify the deformation states; (3) β > 1 implying that permanent strain accumulation ceases in limited cycles and corresponds to the plastic shakedown range, while 0 < β ≤ 1 indicates the temporary steady state, corresponding to the plastic creep range; (4) sluggish decrease or remarkable increase in dε
/dN appeared as CSR ≥ 60%, leading to soil collapsed in limited loading cycles and resulting in an incremental collapse range. The new approach was validated by the crushed tuff aggregates and subgrade materials reported previously. It is expected that the new approach will have wider applicability than the traditional one and can provide technical guidance for the design and construction of substructures in roadway and railway engineering.
Abstract
Recent studies suggest that epi-transcriptome regulation via post-transcriptional RNA modifications is vital for all RNA types. Precise identification of RNA modification sites is essential ...for understanding the functions and regulatory mechanisms of RNAs. Here, we present MultiRM, a method for the integrated prediction and interpretation of post-transcriptional RNA modifications from RNA sequences. Built upon an attention-based multi-label deep learning framework, MultiRM not only simultaneously predicts the putative sites of twelve widely occurring transcriptome modifications (m
6
A, m
1
A, m
5
C, m
5
U, m
6
Am, m
7
G, Ψ, I, Am, Cm, Gm, and Um), but also returns the key sequence contents that contribute most to the positive predictions. Importantly, our model revealed a strong association among different types of RNA modifications from the perspective of their associated sequence contexts. Our work provides a solution for detecting multiple RNA modifications, enabling an integrated analysis of these RNA modifications, and gaining a better understanding of sequence-based RNA modification mechanisms.
We used metagenomic analysis to identify Tacheng tick virus 2 infection in a patient with a history of tick bite in northwestern China. We confirmed the virus with reverse transcription-PCR, virus ...isolation, and genomic analysis. We detected viral RNA in 9.6% of ticks collected from the same region.
PDF
