Biomaterials created from supramolecular peptides, proteins, and their derivatives have been receiving increasing interest for both immunological applications, such as vaccines and immunotherapies, ...as well as ostensibly nonimmunological applications, such as therapeutic delivery or tissue engineering. However, simple rules for either maximizing immunogenicity or abolishing it have yet to be elucidated, even though immunogenicity is a prime consideration for the design of any supramolecular biomaterial intended for use in vivo. Here, we investigated a range of physicochemical properties of fibrillized peptide biomaterials, identifying negative surface charge as a means for completely abolishing antibody and T cell responses against them in mice, even when they display a competent epitope. The work was facilitated by the modularity of the materials, which enabled the generation of a set of co-assembled fibrillar peptide materials with broad ranges of surface properties. It was found that negative surface charge, provided via negatively charged amino acid residues, prevented T cell and antibody responses to antigen-carrying assemblies because it prevented uptake of the materials by antigen-presenting cells (APCs), which in turn prevented presentation of the epitope peptide in the APCs’ major histocompatibility class II molecules. Conversely, positive surface charge augmented the uptake of fibrillized peptides by APCs. These findings suggest that some surface characteristics, such as extensive negative charge, should be avoided in vaccine design using supramolecular peptide assemblies. More importantly, it provides a strategy to switch off potentially problematic immunogenicity for using these materials in nonimmunological applications.
Based on two years of field experiments, under different soil tillage methods and straw management practices, which included conventional tillage (CT), subsoiling (SS), rotary tillage (RT), and ...no-tillage (NT), combined with either straw return (S) or straw removal (0), we characterized the dynamic changes in Δ
C among three height layers upper (U, 240 cm above the ground), middle (M, 120 cm above the ground), and lower (L, 30 cm above the ground) of the summer maize canopy. The Δ
C, the factors affecting it, and the relationships between Δ
C and soil water content (SWC), the leaf area index (LAI), canopy microclimate, and the CO
concentration were elucidated. The results indicated that the Δ
C of summer maize at the pre-filling stage was greater than that at the post-filling stage. Δ
C also varied at different heights, with the order of the Δ
C values being L > U > M. Among the different tillage methods, the Δ
C values were ordered SS
> CT
> RT
> NT
. SS
and NT
significantly increased the LAI; air temperature and relative humidity tended to gradually decrease with the increase in height of summer maize. Correlation analyses of the various influencing factors and Δ
C showed that SWC, LAI, air temperature, and CO
concentration were all positively correlated with Δ
C, in which LAI and air temperature were significantly or extremely significantly positively correlated with Δ
C. In addition, we show that Δ
C can be used as a prediction index for summer maize yield, providing a theoretical basis for future yield research that may save precious time in summer maize breeding efforts.
All-inorganic Sb-perovskite has become a promising material for solar cell applications owing to its air stability and nontoxic lead-free constitution. However, the poor morphology and unexpected ...(001) orientation of Sb-based perovskite films strongly hinder the improvement of efficiency. In this work, two-dimensional Cs3Sb2ClxI9−x with (201) preferred orientation has been successfully fabricated by introducing thiourea (TU) to the precursor solution. The presence of the C=S functional group in TU regulates the crystallization dynamics of Cs3Sb2I9−xClx films and generates the (201) preferred orientation of Cs3Sb2ClxI9−x films, which could effectively improve the carrier transport and film morphology. As a result, the Cs3Sb2I9−xClx perovskite solar cells (PSCs) delivered a power conversion efficiency (PCE) of 2.22%. Moreover, after being stored in nitrogen at room temperature for 60 days, the devices retained above 87.69% of their original efficiency. This work demonstrates a potential pathway to achieve high-efficiency Sb-based PSCs.
Active immunotherapies raising antibody responses against autologous targets are receiving increasing interest as alternatives to the administration of manufactured antibodies. The challenge in such ...an approach is generating protective and adjustable levels of therapeutic antibodies while at the same time avoiding strong T cell responses that could lead to autoimmune reactions. Here we demonstrate the design of an active immunotherapy against TNF-mediated inflammation using short synthetic peptides that assemble into supramolecular peptide nanofibers. Immunization with these materials, without additional adjuvants, was able to break B cell tolerance and raise protective antibody responses against autologous TNF in mice. The strength of the anti-TNF antibody response could be tuned by adjusting the epitope content in the nanofibers, and the T-cell response was focused on exogenous and non-autoreactive T-cell epitopes. Immunization with unadjuvanted peptide nanofibers was therapeutic in a lethal model of acute inflammation induced by intraperitoneally delivered lipopolysaccharide, whereas formulations adjuvanted with CpG showed comparatively poorer protection that correlated with a more Th1-polarized response. Additionally, immunization with peptide nanofibers did not diminish the ability of mice to clear infections of Listeria monocytogenes. Collectively this work suggests that synthetic self-assembled peptides can be attractive platforms for active immunotherapies against autologous targets.
Epitope content plays a critical role in determining T‐cell and antibody responses to vaccines, biomaterials, and protein therapeutics, but its effects are nonlinear and difficult to isolate. Here, ...molecular self‐assembly is used to build a vaccine with precise control over epitope content, in order to finely tune the magnitude and phenotype of T helper and antibody responses. Self‐adjuvanting peptide nanofibers are formed by co‐assembling a high‐affinity universal CD4+ T‐cell epitope (PADRE) and a B‐cell epitope from Staphylococcus aureus at specifiable concentrations. Increasing the PADRE concentration from micromolar to millimolar elicited bell‐shaped dose‐responses that are unique to different T‐cell populations. Notably, the epitope ratios that maximize T follicular helper and antibody responses differed by an order of magnitude from those that maximized Th1 or Th2 responses. Thus, modular materials assembly provides a means of controlling epitope content and efficiently skewing the adaptive immune response in the absence of exogenous adjuvant; this approach may contribute to the development of improved vaccines and immunotherapies.
Co‐assembly of peptide epitopes is used to integrate T‐cell epitopes at a range of doses into self‐adjuvanting nanofiber vaccines. Helper T‐cell activation and differentiation are shown to follow a set of bell‐shaped dose‐response curves, peaking at different concentrations for different types of helper T cells. Thus, noncovalent co‐assembly is a precise approach to generating modular vaccines with tunable properties.
Soil degradation is one of the main problems in agricultural production and leads to decreases in soil quality and productivity. Improper farming practices speed this process and are therefore not ...conducive to food security. The North China Plain (NCP) is a key agricultural area that greatly influences food security in China. To explore the effects of different tillage measures on aggregate-associated organic carbon (AOC), the accumulation and transport of dry matter, and maize yield, and to identify the most suitable tillage method for use on the NCP, a field experiment was conducted at Shandong Agricultural University from 2016-2017 using plots that have been farmed using conservation tillage since 2002.
In this study, Zhengdan 958 summer maize was used as the test material and undisturbed soil and plant samples were obtained under four tillage methods-no-tillage (NT, tillage depth: 0 cm); rotary tillage (RT, tillage depth: 10 cm); conventional tillage (CT, tillage depth: 20 cm); subsoiling (SS, tillage depth: 40 cm)-which were used to determine the AOC and dry matter contents, as well as the yields of two summer maize growing seasons. Each sample was replicated three times and the AOC content was determined via potassium dichromate oxidation colorimetry. Potassium dichromate oxidized organic carbon in organic matter was employed to reduce hexadecent chromium into green trivalent chromium. Colorimetry was then used to determine the amount of reduced trivalent chromium and calculate the organic matter content.
The resulting data were statistically analyzed and the results showed that, compared with CT, the AOC contents with NT and SS increased by 5.65% and 9.73%, respectively, while that with RT decreased by 0.12%. Conventional tillage resulted in the highest mean dry matter weight when the maize reached maturity, which was 19.19%, 9.83%, and 3.38% higher than those achieved using NT, RT, and SS, respectively. No significant difference was found between CT and SS treatments, both of which tended to increase the accumulation of dry matter as well as its contribution of assimilates to grain yield post-anthesis. Compared with CT, the mean yield increased at a rate of 0.18% with SS, while yields declined at rates of 17.17% and 11.15 with NT and RT, respectively. The yield with NT was the lowest, though the harvest indices with NT and SS were higher than those with RT and CT. Overall, SS increased the accumulation of dry matter and its contribution of assimilates to grain yields post-anthesis, as well as the AOC content and yields, making it the ideal tillage method for the NCP.
All-inorganic perovskite solar cells are attractive photovoltaic devices because of their excellent optoelectronic performance and thermal stability. Unfortunately, the currently used efficient ...inorganic perovskite materials can spontaneously transform into undesirable phases without light-absorption properties. Studies have been carried out to stabilize all-inorganic perovskite by mixing low-dimensional perovskite. Compared with organic two-dimensional (2D) perovskite, inorganic 2D Cs2PbI2Cl2 shows superior thermal stability. Our group has successfully fabricated 2D/3D mixed-dimensional Cs2PbI2Cl2/CsPbI2.5Br0.5 films with increasing phase stability. The high boiling point of dimethyl sulfoxide (DMSO) makes it a preferred solvent in the preparation of Cs2PbI2Cl2/CsPbI2.5Br0.5 inorganic perovskite. When the perovskite films are prepared by the one-step solution method, it is difficult to evaporate the residual solvent molecules from the prefabricated films, resulting in films with rough surface morphology and high defect density. This study used the rapid precipitation method to control the formation of perovskite by treating it with methanol/isopropanol (MT/IPA) mixed solvent to produce densely packed, smooth, and high-crystallized perovskite films. The bulk defects and the carrier transport barrier of the interface were effectively reduced, which decreased the recombination of the carriers in the device. As a result, this effectively improved photoelectric performance. Through treatment with MT/IPA, the photoelectric conversion efficiency (PCE) of solar cells prepared in the N2 atmosphere increased from 13.44% to 14.10%, and the PCE of the device prepared in the air increased from 3.52% to 8.91%.
Yellow River sediment is the potential resource for saline–sodic soil reclamation. Experiments of one-dimensional soil columns were conducted to investigate the upward and downward soil water ...transportation characteristics for saline–sodic soil mixed with different sediment addition (0, 10, 20 kg/m2 in the top 20 cm layer). The saturated hydraulic conductivity, ratio of macroporosity, cumulative capillary adsorption and infiltration rate all increased with the increase in sediment addition. No significant differences were detected for both the initial capillary rise rate and the initial infiltration rate for the upward and downward water transportation treatments, respectively. The average adsorption and infiltration rates showed an increasing trend with the increased sediment addition. The initial and average infiltration rates were higher than the initial capillary rise rate and average adsorption rates. The Philip model seems the optimal choice for the dynamic simulation of both upward and downward soil water transportation. The results may provide useful information for soil salinization amelioration.
•ST and NT increased SOC compared to CT.•SOC, maize yield, and wheat yield increased during 11 yr.•Crop yield was strongly and positively correlated with SOC storage in this 11 yr study.•STS is an ...optimal method to improve SOC storage and crop yield.
A long-term experiment for testing different tillage methods and straw management practices was carried out in the Northern China Plain (NCP) since 2002 in a double cropping system (winter wheat and summer maize) rotated annually. Data for 11 yr (2005–2015) was collected to compare the long-term effects of six agricultural practices on soil organic carbon (SOC) storage, crop yield, and yield stability. The six agricultural methods comprised of two main factors (i) tillage practices with three modalities—conventional tillage (CT), no-tillage (NT), and subsoiling (ST); and (ii) straw management with two modalities—straw return (S) and straw removal (0). Here, straw was usually defined as crop residue cut and removed with harvest. Finally, the six treatment combinations were represented as CT0, NT0, ST0, CTS, NTS, and STS. The SOC storage showed similar dynamic changing trends under all treatments, but was higher in NT and ST and straw return plots than in CT0 plots. Average SOC storage under STS and NTS reached 14.1, and 13.1 g kg−1, respectively. After 2005, both tillage practice and residue management affected SOC storage significantly. Cumulative yields for 11 yr with maize and wheat were higher for ST than NT and CT both with straw removal and straw return. Average crop yield increased by 6.2 and 20.1% in winter wheat and by 11.0 and 21.6% in summer maize, respectively, in ST0 and STS, when compared to CT0. NT, ST, and straw return increased crop yield stability, with STS being the most stable. Variability in STS was only 11.3% for winter wheat and 8.8% for summer maize. Pearson correlation analysis showed that winter wheat and summer maize yields were significantly and positively correlated with SOC storage. Subsoiling with straw return (STs) did not result in higher SOC than NTs after 11 yr, but it resulted in the highest cumulative yield for wheat and maize, and the highest yield stability for wheat. When straw was removed, SOC after 11 yr was highest for NT, but cumulative yields for wheat and maize were highest for ST. STS is firstly an optimal method to improve SOC storage, crop yield, and yield stability in the NCP.
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