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Wang, Mingming

Publications and source records attributed to Wang, Mingming.

6 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Responses of soil organic carbon to climate extremes under warming across global biomes

The impact of more extreme climate conditions under global warming on soil organic carbon (SOC) dynamics remains unquantified. Here, in this study, we estimate the response of SOC to climate extreme shifts under 1.5 °C warming by combining a space-for-time substitution approach and global SOC measurements (0–30 cm soil). Most extremes (22 out of 33 assessed extreme types) exacerbate SOC loss under warming globally, but their effects vary among ecosystems. Only decreasing duration of cold spells exerts consistent positive effects, and increasing extreme wet days exerts negative effects in all ecosystems. Temperate grasslands and croplands negatively respond to most extremes, while positive responses are dominant in temperate and boreal forests and deserts. In tundra, 21 extremes show neutral effects, but 11 extremes show negative effects with stronger magnitude than in other ecosystems. Our results reveal distinct, biome-specific effects of climate extremes on SOC dynamics, promoting more reliable SOC projection under climate change.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Global soil profiles indicate depth-dependent soil carbon losses under a warmer climate

Soil organic carbon (SOC) changes under future climate warming are difficult to quantify in situ. Here we apply an innovative approach combining space-for-time substitution with meta-analysis to SOC measurements in 113,013 soil profiles across the globe to estimate the effect of future climate warming on steady-state SOC stocks. We find that SOC stock will reduce by 6.0 ± 1.6% (mean±95% confidence interval), 4.8 ± 2.3% and 1.3 ± 4.0% at 0–0.3, 0.3–1 and 1–2 m soil depths, respectively, under 1 °C air warming, with additional 4.2%, 2.2% and 1.4% losses per every additional 1 °C warming, respectively. The largest proportional SOC losses occur in boreal forests. Existing SOC level is the predominant determinant of the spatial variability of SOC changes with higher percentage losses in SOC-rich soils. Our work demonstrates that warming induces more proportional SOC losses in topsoil than in subsoil, particularly from high-latitudinal SOC-rich systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Biomimetic antibiotics based on amphiphilic peptoids and their self-assembly

Bacterial infections pose a serious threat to mankind. Inspired by antimicrobial peptides (AMPs) and their membrane-disruption mechanism, there is immense interest in the design and development of synthetic mimetics for antibacterial applications, overcoming the intrinsic drawbacks of AMPs (e.g. susceptibility to proteolytic degradation). Herein, by exploiting the self-assembly and pore-forming capabilities of sequence-defined peptoids, we discovered a new family of low molecular weight peptoid antibiotics that exhibited excellent broad-spectrum activity and high selectivity toward a panel of clinically significant Gram-positive and Gram-negative bacterial strains. Tuning peptoid sidechain chemistry and structure enabled us to tune the efficacy of antimicrobial activity and study the structure–activity relationship. These findings offer a novel approach to identify new families of antimicrobial peptoids and correlate the pore-forming capability of self-assembling peptoids with their antimicrobial activities. Because peptoids are highly robust and biocompatible, we exhibit these peptoid-based antibiotics will be significant for combating the emerging drug resistance.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Sequence-Defined Nanotubes Assembled from IR780-Conjugated Peptoids for Chemophototherapy of Malignant Glioma

Near-infrared (NIR) laser-induced phototherapy through NIR agents has demonstrated the great potential for cancer therapy. However, insufficient tumor killing due to the nonuniform heat or cytotoxic singlet oxygen ( 1 O 2 ) distribution over tumors from phototherapy results in tumor recurrence and inferior outcomes. To achieve high tumor killing efficacy, one of the solutions is to employ the combinational treatment of phototherapy with other modalities, especially with chemotherapeutic agents. In this paper, a simple and effective multimodal therapeutic system was designed via combining chemotherapy, photothermal therapy (PTT), and photodynamic therapy (PDT) to achieve the polytherapy of malignant glioma which is one of the most aggressive tumors in the brain. IR-780 (IR780) dye-labeled tube-forming peptoids (PepIR) were synthesized and self-assembled into crystalline nanotubes (PepIR nanotubes). These PepIR nanotubes showed an excellent efficacy for PDT/PTT because the IR780 photosensitizers were effectively packed and separated from each other within crystalline nanotubes by tuning IR780 density; thus, a self-quenching of these IR780 molecules was significantly reduced. Moreover, the efficient DOX loading achieved due to the nanotube large surface area contributed to an efficient and synergistic chemotherapy against glioma cells. Given the unique properties of peptoids and peptoid nanotubes, we believe that the developed multimodal DOX-loaded PepIR nanotubes in this work offer great promises for future glioma therapy in clinic.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Highly Bright and Photostable Two-Dimensional Nanomaterials Assembled from Sequence-Defined Peptoids

Free-standing two-dimensional (2D) organic nanomaterials are highly attractive for biological applications because of their unique structural properties and high biocompatibility. Herein, we designed and synthesized a new class of highly bright and photostable membrane-mimetic 2D nanosheets from sequence-defined peptoids. These nanosheets exhibited the high quantum yield and photostability as a result of the precise placement and ordering of dansyl dye molecules within crystalline nanosheets. We further showed the use of these nanosheets as biocompatible and programmable probes for live cell imaging and cell labeling. Furthermore, by programing these nanosheets with different surface charges, we achieved the enhanced lysosome escape of these nanosheets, showing their great potential as nanocarriers for the efficient intracellular delivery of macromolecular drugs.

2D nanomaterials↗