Soft Matter
·
2015
·Vol. 11
·期 35
·7059-7065
·
IF 4.029
Lei Hou,Peiyi Wu
The UCST-type transition of poly(acrylamide-co-acrylonitrile) (P(AAm-co-AN)) (molar fraction of AN: 13.3%; PDI = 3.2) in H2O and D2O is explored and compared by applying turbidity, DLS as well as FTIR measurements. The transition temperature of P(AAm-co-AN) in D2O is observed to be almost 10 °C higher than that in H2O at the same concentration, demonstrating a dramatic solvent isotope effect. Such a phenomenon could be rooted from a stronger interaction among polymer chains in D2O than in H2O, as indicated from DLS results. It is also observed in second-derivative analysis of FTIR spectra in the ν(CO) region, where all CO groups participate in the formation of inter-/intra-chain hydrogen bonds (CO⋯H–N) in D2O while there is still part of relatively “free” CO groups in H2O. Moreover, we find in the temperature-dependent FTIR spectra that CN groups exhibit hydrating behavior while CO groups present increased inter-/intra-molecular hydrogen bonding interaction (CO⋯H–N) upon cooling, revealing the later process to be the driving force of the UCST-type transition.
研究领域:
高分子化学
·
物理化学
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高影响因子
MICROCHIMICA ACTA
·
2026
·Vol. 193
·期 10
·689
·
IF 5.4
Liu Shijie,Zhao Lijun,Bai Yueyu,Ding Qian,Ma Yangyang,Li Miaoyun,Liang Dong,Liu Yanxia,Li Haoyun,Sun Lingxia
Achieving accurate quantification and counting of active lactic acid bacteria (LAB) is an important technical guarantee for the industrial production and application of LAB and their products. In this study, a gold nanoparticles@polyvinylpyrrolidone/sodium alginate (AuNPs@PVP/SA) hydrogel SERS sensor with outstanding stability and sensitivity was developed. Utilizing this platform as a substrate material to mitigate the “coffee ring” effect, we explored a strategy for the precise quantitative determination of mixed active LAB based on the AuNPs@PVP/SA hydrogel SERS platform and D 2 O-probed Raman spectroscopy technology. The results indicated that the SERS platform based on AuNPs@PVP/SA hydrogel exhibited excellent spectral reproducibility for LAB as a SERS substrate material, with a significantly reduced “coffee ring” effect. This strategy enabled rapid and quantitative detection of active lactic acid bacteria (LAB), with a limit of detection (LOD) of 10 CFU/mL. Moreover, the strategy had excellent analytical capabilities for the qualitative identification and precise quantification of different species of active LAB in actual samples, achieving an average accuracy of 98.67% with RSD values all less than 5%. It provides a potential technical support for the dynamic monitoring of relative abundance and metabolic phenomena of mixed active LAB in co-culture systems during actual industrial production. Graphical
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ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Yunhe Lang,Shihong Wu,Qin Yang,Yanju Luo,Xia Jiang,Peng Wu
D2O plays important roles in a variety of fields (such as the nuclear industry and bioorganic analysis), and thus its isotopic purity (H2O contents) is highly concerned. Due to its highly similar physical properties to H2O and large excess amounts of H2O over D2O, it is challenging to distinguish D2O from H2O. On the basis of the characteristic NIR-II phosphorescence of singlet oxygen (1O2), and the fact that H2O is a more efficient quencher for 1O2 than D2O, here, we proposed to simply use the 1275 nm emission of 1O2 for the analysis of the isotopic purity of D2O. In normal cases (a xenon lamp for excitation), such steady-state emission is extremely weak for valid analytical applications, we thus employed laser excitation for intensification. To this goal, a series of photosensitizers were screened, and eventually polythiophene PT10 was selected with high singlet oxygen quantum yield (ΦΔ = 0.51), high H2O/D2O contrast, and excellent photostability. Upon excitation with a 445 nm laser, a limit of detection (LOD, 3σ) of 0.1% for H2O in D2O was achieved. The accuracy of the proposed method was verified by the analysis of the isotopic purity of several D2O samples (with randomly added H2O). More interestingly, the hygroscopicity of D2O was sensitively monitored with the proposed probe in a real-time manner; the results of which are important for strengthening the care of D2O storage and the importance of humidity control during related investigations. Besides D2O isotopic purity evaluation, this work also indicated the potential usefulness of the NIR-II emission of singlet oxygen in future analytical detection.
研究领域:
分析化学
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核工业
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生物有机分析
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Chem
·
2025
·Vol. 12
·期 3
·
IF 19.6
Yu-He Liang,Jia-Xin Kang,Yan Wang,Yi-Ge Li,Hou-Ji Cao,Qianyi Zhao,Xuenian Chen,Yan-Na Ma
The selective B–H functionalization of carboranes has received considerable attention because of their wide applications in functional materials, catalysis, and pharmaceuticals. Deuterium-labeling experiments and kinetic-isotope-effect experiments are two important tools for mechanistic studies on the selective B–H activation of carboranes. Thus, developing an effective method for the synthesis of perdeuterated carboranes is highly desirable. Herein, we present a practical method for synthesizing perdeuterated carboranes via Pd(II)-catalyzed B–H activation by using D 2 O as a deuterium source. This protocol features extraordinary functional-group tolerance, high levels of deuterium incorporation, and ease of scaling. Mechanistic studies illustrate that the deuteration reaction proceeds via Pd(II)-catalytic electrophilic H/D exchange and subsequent intermolecular Pd migration. The same degree of deuterium incorporation across all boron vertices indicates that the Pd-migration step is faster than the electrophilic palladation step. Additionally, the versatility of this method is reflected in the deuteration of other boron clusters.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2018
·Vol. 103
·期 3
·1455-1464
·
IF 3.34
Olaniyi Oladipo Oladiti,Yang Kai,Zhu Yong-Guan,Cui Li
Biodegradation of cellulose-rich substrates is an indispensable process for soil carbon replenishment in various ecological niches. Biodegradation of cellulose has been studied extensively via an enzyme assay to quantify the amount of cellulase with a view to identify effective cellulose degraders. However, a bulk enzyme assay undermines the role of physiological heterogeneity between cells; it is therefore imperative to opt out for a more effective method such as single-cell Raman spectroscopy combined with heavy water (D 2 O) to reveal active cellulose degraders. Cellular incorporation of D 2 O-derived D produces a new C-D Raman band which can act as a quantitative indicator of microbial activity. In this study, metabolic responses of seven cellulose-degrading bacteria to carboxymethylcellulose (CMC) and glucose were evaluated via the C-D Raman band. On the basis of % C-D, CMC was demonstrated to be most efficiently metabolized by Bacillus velezensis 2a-9 and Providencia vermicola 5a-9(b). Metabolic activity between individual cells of B . velezensis and P . vermicola towards CMC ranged from approximately 8 to 27% and 6 to 16%, respectively, clearly indicating heterogeneous degradation activities among isogenic populations. Linear correlation between % C-D and specific endoglucanase activity validated Raman results on CMC-degrading activity. Also, % C-D obtained from bacteria cultivated with only glucose was around 60% higher than that obtained from CMC, indicating the preference of bacteria for simple sugar glucose than CMC. In conclusion, Raman spectroscopy combined with heavy water is a sensitive analytical technique to reveal cellulose degraders and their degrading activities.
研究领域:
微生物学
·
环境科学
·
光谱学
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PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
·
2022
·Vol. 119
·期 40
·e2201473119
·
IF 12.779
Hong-Zhe Li,Kai Yang,Hu Liao,Simon Bo Lassen,Jian-Qiang Su,Xian Zhang,Li Cui,Yong-Guan Zhu
Antimicrobial resistance (AMR) in soils represents a serious risk to human health through the food chain and human–nature contact. However, the active antibiotic-resistant bacteria (ARB) residing in soils that primarily drive AMR dissemination are poorly explored. Here, single-cell Raman-D2O coupled with targeted metagenomics is developed as a culture-independent approach to phenotypically and genotypically profiling active ARB against clinical antibiotics in a wide range of soils. This method quantifies the prevalence (contamination degree) and activity (spread potential) of soil ARB and reveals a clear elevation with increasing anthropogenic activities such as farming and the creation of pollution, thereby constituting a factor that is critical for the assessment of AMR risks. Further targeted sorting and metagenomic sequencing of the most active soil ARB uncover several uncultured genera and a pathogenic strain. Furthermore, the underlying resistance genes, virulence factor genes, and associated mobile genetic elements (including plasmids, insertion sequences, and prophages) are fully deciphered at the single-cell level. This study advances our understanding of the soil active AMR repertoire by linking the resistant phenome to the genome. It will aid in the risk assessment of environmental AMR and guide the combat under the One Health framework.
研究领域:
微生物学
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环境科学
·
基因组学
·
公共卫生
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高影响因子
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