Search

Black phosphorus (BP) is a layered semiconductor with a high mobility of up to ∼1000 cm2 V-1s-1 and a narrow bandgap of ∼0.3 eV, and shows potential applications in thermoelectrics. In stark contrast to most other layered materials, electrical and thermoelectric properties in the basal plane of BP are highly anisotropic. To elucidate the mechanism for such anisotropy, we fabricated BP nanoribbons (∼100 nm thick) along the armchair and zigzag directions, and measured the transport properties. It is found that both the electrical conductivity and Seebeck coefficient increase with temperature, a behavior contradictory to that of traditional semiconductors. The three-dimensional variable range hopping model is adopted to analyze this abnormal temperature dependency of electrical conductivity and Seebeck coefficient. The hopping transport of the BP nanoribbons, attributed to high density of trap states in the samples, provides a fundamental understanding of the anisotropic BP for potential thermoelectric applications.

Hydrostatic pressure applied using diamond anvil cells (DAC) has been widely explored to modulate physical properties of materials by tuning their lattice degree of freedom. Independently, electrical field is able to tune the electronic degree of freedom of functional materials via, for example, the field-effect transistor (FET) configuration. Combining these two orthogonal approaches would allow discovery of new physical properties and phases going beyond the known phase space. Such experiments are, however, technically challenging and have not been demonstrated. Herein, we report a feasible strategy to prepare and measure FETs in a DAC by lithographically patterning the nanodevices onto the diamond culet. Multiple-terminal FETs were fabricated in the DAC using few-layer MoS2 and BN as the channel semiconductor and dielectric layer, respectively. It is found that the mobility, conductance, carrier concentration, and contact conductance of MoS2 can all be significantly enhanced with pressure. We expect that the approach could enable unprecedented ways to explore new phases and properties of materials under coupled mechano-electrostatic modulation.

Owing to the presence of a substantial concentration of chlorine in seawater, the anode still faces severe chlorine corrosion, especially the water splitting operated at high current densities. Herein, the cost‐effective and scalable NiFe layered double hydroxides with carbonate intercalation (named as NiFe LDH_CO32−) are synthesized utilizing the etching‐hydrolysis and ion exchange strategies under ambient conditions. Experimental findings demonstrate that NiFe LDH_CO32− shows excellent stability at 500 and 1000 mA cm−2 for 1000 h under alkaline simulated seawater. Additionally, a two‐electrode system offers great stability at current densities ranging from 100 to 1000 mA cm−2 over a duration of 400 h in alkaline seawater. This remarkably catalytic stability can be ascribed to the etching‐hydrolysis and carbonate intercalation strategies. The etching‐hydrolysis strategy leads to an integrated electrode for the catalyst‐carrier, enhancing the adhesion between them, and retarding hence the divorce of catalysts from the carrier. Theoretical calculations suggest that the carbonate intercalation weakens the adsorbability of chlorine on catalysts and hinders the coupling of metal atoms with chlorine, thereby impeding the anode corrosion caused by chlorine and improving catalytic stability. More importantly, this strategy has been extended to the preparation of other layered double hydroxides with carbonate intercalation. [ABSTRACT FROM AUTHOR]

The integrated dual-channel pathway is regarded as an ideal process for photocatalytic H2O2 production. However, it is a key scientific challenge to rationally design photocatalysts for achieving H2O2 production through such a dual-channel pathway. Here, we designed surface oxygen vacancy-modified BiOIO3 (BIO-OVs-x) with spatially separated redox reaction centers by constructing a facet heterojunction for directly utilizing O2 and H2O to photosynthesize H2O2. Under white light irradiation, optimal BIO-OVs-2 exhibited the highest H2O2 production rate of 215.5 μmol g–1 h–1, which was 3 times more than that of BiOIO3, as well as an apparent quantum yield of 5.76% at 350 nm. Photoelectrochemical experiments confirmed that the introduction of oxygen vacancies boosted the efficiency of charge separation and transfer and adjusted the band structure. Control experiments and theoretical studies elucidated photocatalytic reaction active sites and the charge transport mechanism of BIO-OV catalysts. More importantly, the introduction of oxygen vacancies in BiOIO3 reduced the free energy for OH* of the water oxidation reaction and promoted the occurrence of the water oxidation reaction. This work provides a valuable basis for the fine design of a high-performance photocatalyst and for understanding the mechanism of hydrogen peroxide production. [ABSTRACT FROM AUTHOR]

This study was conducted to elucidate the intestinal damage induced by the IPEC-J2 cell culture-passaged PDCoV. The results showed that PDCoV disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, PDCoV induced an imbalance in the intestinal flora and disturbed its stability. Microbial community profiling revealed bacterial enrichment (e.g., Proteobacteria) and reduction (e.g., Firmicutes and Bacteroidetes) in the PDCoV-inoculated piglet model. In addition, metabolomics analysis indicated that 82 named differential metabolites were successfully quantified, including 37 up-regulated and 45 down-regulated metabolites. Chenodeoxycholic acid, sphingosine, and oleanolic aldehyde levels were reduced in PDCoV-inoculated piglets, while phenylacetylglycine and geranylgeranyl-PP levels were elevated. Correlation analysis indicated a negative correlation between Escherichia-Shigella and choline, succinic acid, creatine, phenyllactate, and hippuric acid. Meanwhile, Escherichia-Shigella was positively correlated with acetylcholine, L-Glutamicacid, and N-Acetylmuramate. Roseburia, Lachnospiraceae_UCG-010, Blautia, and Limosilactobacillus were negatively and positively correlated with sphingosine, respectively. These data suggested PDCoV-inoculated piglets exhibited significant taxonomic perturbations in the gut microbiome, which may result in a significantly altered metabolomic profile. [ABSTRACT FROM AUTHOR]

We aimed to investigate the CXCL13 concentration of the serum and cerebral spinal fluid (CSF) in human immunodeficiency virus (HIV)-negative latent syphilis patients with treatment failure and explore the change in CXCL13 after treatment. Sixty-eight latent syphilis patients with treatment failure (failure group), 68 syphilis patients with successful treatment (seroconversion group) and 18 patients with non-inflammatory diseases of the nervous system (control group) were included and serum and CSF were collected. Enzyme-linked immunosorbent assay was employed to detect the CXCL13 in the serum and CSF. Results showed that the serum CXCL13 concentration was comparable among three groups, and the CSF leukocyte count, IgG index and CXCL13 concentration in the failure group were significantly higher than those in the seroconversion group and control group (P < 0.05, P < 0.01). CSF CXCL13 concentration in the failure group was positively related to the CSF leukocyte count (r = 0.3594, P < 0.001). Of the 68 patients in the treatment failure group, neurosyphilis was found in 17 (25.0%). In conclusion, involvement of nervous system is one of the reasons for the treatment failure in patients with latent syphilis. Detection of CSF CXCL13 concentration is helpful for the diagnosis and therapeutic evaluation of HIV-negative latent syphilis patients with treatment failure and neurosyphilis.

Summary: Major polyamines include putrescine, spermidine, spermine and thermospermine, which play vital roles in growth and adaptation against environmental changes in plants. Thermospermine (T‐Spm) is synthetised by ACL5. The function of ACL5 in rice is still unknown. In this study, we used a reverse genetic strategy to investigate the biological function of OsACL5. We generated several knockout mutants by pYLCRISPR/Cas9 system and overexpressing (OE) lines of OsACL5. Interestingly, the OE plants exhibited environmentally‐dependent leaf rolling, smaller grains, lighter 1000‐grain weight and reduction in yield per plot. The area of metaxylem vessels of roots and leaves of OE plants were significantly smaller than those of WT, which possibly caused reduction in leaf water potential, resulting in leaf rolling with rise in the environmental temperature and light intensity and decrease in humidity. Additionally, the T‐Spm contents were markedly increased by over ninefold whereas the ethylene evolution was reduced in OE plants, suggesting that T‐Spm signalling pathway interacts with ethylene pathway to regulate multiple agronomic characters. Moreover, the osacl5 exhibited an increase in grain length, 1000‐grain weight, and yield per plot. OsACL5 may affect grain size via mediating the expression of OsDEP1, OsGS3 and OsGW2. Furthermore, haplotypes analysis indicated that OsACL5 plays a conserved function on regulating T‐Spm levels during the domestication of rice. Our data demonstrated that identification of OsACL5 provides a theoretical basis for understanding the physiological mechanism of T‐Spm which may play roles in triggering environmentally dependent leaf rolling; OsACL5 will be an important gene resource for molecular breeding for higher yield. [ABSTRACT FROM AUTHOR]

This study examines learning gains of college students' performance in critical thinking, reading, writing, and mathematics as assessed by the ETS Proficiency Profile (EPP). In this study, students' college learning gain was estimated by calculating the score differences between their first and last test administrations. Results revealed that (a) after being in college for one or two years, students did not demonstrate significant learning gains, (b) after three or more years, students made small to moderate gains on the EPP total score, and reading and mathematics subscales, (c) after four or five years, students made small to moderate learning gains on EPP total score and all four subscales, and (d) among various demographic and college-level variables, college experience was the largest significant predictor of students' learning gain, followed by first-year GPA. Implications of these results are discussed.