Photochemical transformation of perfluoroalkyl acid precursors in water using engineered nanomaterials

The production of perfluoroalkyl acids (PFAAs) has been phased out over recent decades; however, no significant decline in their environmental concentrations has been observed. This is partly due to the photochemical decomposition of PFAAs precursors (PrePFAAs) which remain in extensive use. The decomposition of PrePFAAs may be accelerated by the light-activated engineered nanomaterials (ENMs) in water. In light of this hypothesis, we investigated the photochemical transformation of three PrePFAAs, which are 8:2 fluorotelomer sulfonic acid (8:2 FTSA), 8:2 fluorotelomer alcohol (8:2 FTOH), and 2-(N-ethylperfluorooctane-1-sulfonamido ethyl] phosphate (SAmPAP), in the presence of six ENMs under simulated sunlight irradiation. The transformation rates of 8:2 FTSA and 8:2 FTOH were increased by 2–6 times when in the presence of six ENMs. However, most of ENMs appeared to inhibit the decomposition of SAmPAP. The transformation rates of PrePFAAs were found to depend on the yield of reactive oxygen species generated by ENMs, but the rates were also related to compound photo-stability, adsorption to surfaces, and photo-shielding effects. The PrePFAAs are transformed to perfluorooctanoic acid (PFOA) or/and perfluorooctane sulfonate (PFOS) with higher toxicity and longer half-life, PFOA or PFOS and a few PFAAs having shorter carbon chain lengths. Higher concentrations of the PFAAs photodegradation products were observed in the presence of most of the ENMs

Photochemical transformation of perfluoroalkyl acid precursors in water using engineered nanomaterials

The production of perfluoroalkyl acids (PFAAs) has been phased out over recent decades; however, no significant decline in their environmental concentrations has been observed. This is partly due to the photochemical decomposition of PFAAs precursors (PrePFAAs) which remain in extensive use. The decomposition of PrePFAAs may be accelerated by the light-activated engineered nanomaterials (ENMs) in water. In light of this hypothesis, we investigated the photochemical transformation of three PrePFAAs, which are 8:2 fluorotelomer sulfonic acid (8:2 FTSA), 8:2 fluorotelomer alcohol (8:2 FTOH), and 2-(N-ethylperfluorooctane-1-sulfonamido ethyl] phosphate (SAmPAP), in the presence of six ENMs under simulated sunlight irradiation. The transformation rates of 8:2 FTSA and 8:2 FTOH were increased by 2–6 times when in the presence of six ENMs. However, most of ENMs appeared to inhibit the decomposition of SAmPAP. The transformation rates of PrePFAAs were found to depend on the yield of reactive oxygen species generated by ENMs, but the rates were also related to compound photo-stability, adsorption to surfaces, and photo-shielding effects. The PrePFAAs are transformed to perfluorooctanoic acid (PFOA) or/and perfluorooctane sulfonate (PFOS) with higher toxicity and longer half-life, PFOA or PFOS and a few PFAAs having shorter carbon chain lengths. Higher concentrations of the PFAAs photodegradation products were observed in the presence of most of the ENMs

Numerical and experimental analysis on green laser crystallization of amorphous silicon thin films

The laser fluence effect on crystallization of amorphous silicon irradiated by a frequency-doubled Nd: YAG laser has been studied both theoretically and experimentally. An effective numerical model is set up to predict the melting threshold and the optimized laser fluence for crystallization of 200nm amorphous silicon. Temperature distribution with time and melt depth are analyzed. Besides the model, Raman spectra of thin films treated with different fluences are measured to confirm the phase transition and to determine the optimized fluence. The calculating results accord well with those obtained from the experimental data in this research

Lactulose vs Polyethylene Glycol for Bowel Preparation: A Single-Center, Prospective, Randomized Controlled Study Based on BMI

INTRODUCTION: Colonoscopy is currently considered as one of the principal techniques to diagnose the colorectal diseases. Admittedly, qualified bowel preparation before colonoscopy is a premise for high-quality examination. Lower quality bowel preparation might seriously impede visualization of the intestinal mucosa, resulting in missed and misdiagnosed intestinal lesions. Therefore, it is necessary to choose the appropriate oral laxative based on the guarantee of safety and efficacy. METHODS: This prospective randomized controlled study was conducted to compare lactulose oral solution and polyethylene glycol (PEG) electrolyte powder for bowel preparation using the following indicators: Boston Bowel Preparation Scale, Bowel Bubble Score, detection rate of adenoma and lesion, patients\u27 satisfaction, and adverse effects. Our study investigated the suitability of 2 bowel preparation reagents for patients with different body mass indices mainly based on body mass index (BMI). RESULTS: In the lactulose group, there was a significant improvement in the quality of bowel preparation compared with those in the PEG group ( P \u3c 0.05), especially in people with normal BMI and higher BMI. Compared with the PEG group, individuals in the lactulose group had a significantly higher adenoma detection rate (50% vs 33.5%, P \u3c 0.05) and taste scores (8.82 vs 6.69, P \u3c 0.05), as well as significantly fewer adverse reactions (6.5% vs 32.5%, P \u3c 0.05). DISCUSSION: Lactulose oral solution is superior to PEG in bowel preparation quality and taste, especially in normal BMI and higher BMI groups. It can be used clinically as a potential and promising bowel preparation agent in the future. Clinical Trial registration number: ChiCTR2100054318

Modeling and Experimental Verification of an Electromagnetic and Piezoelectric Hybrid Energy Harvester

This paper describes mathematical models of an electromagnetic and piezoelectric hybrid energy harvesting system and provides an analysis of the relationship between the resonance frequency and the configuration parameters of the system. An electromagnetic and piezoelectric energy harvesting device was designed and the experimental results showed good agreement with the analytical results. The maximum load power of the hybrid energy harvesting system achieved 4.25 mW at a resonant frequency of 18 Hz when the acceleration was 0.7 g, which is an increase of 15% compared with the 3.62 mW achieved by a single electromagnetic technique

Characterization of Subtilin L-Q11, a Novel Class I Bacteriocin Synthesized by Bacillus subtilis L-Q11 Isolated From Orchard Soil

Bacteriocins are peptides or proteins synthesized by bacterial ribosomes that show killing or inhibitory activities against different groups of bacteria. Bacteriocins are considered potential alternatives to traditional antibiotics, preservatives in pharmaceutical and food industries. A strain L-Q11 isolated from orchard soil was phylogenetically characterized as Bacillus subtilis based on 16S rRNA gene sequencing analysis. A novel class I bacteriocin (Subtilin L-Q11), was identified and purified from L-Q11 cell-free supernatant in a four-step procedure, including salt precipitation, cation exchange, gel filtration, and reverse-phase high-performance liquid chromatography (RP-HPLC). The molecular mass (3,552.9 Da) of this novel bacteriocin was determined by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The purified Subtilin L-Q11 exhibited optimal features in pH tolerance, thermostability, and sensitivity to proteases. Further, Subtilin L-Q11 showed inhibitory activities against a number of bacteria including some human pathogens and food spoilage bacteria, in particular Staphylococcus aureus. All these important features make this novel bacteriocin a potential candidate for the development of a new antibacterial drug or food preservative in the future

Ecological stoichiometric characteristics of three dominant fish species from the Beibu Gulf: inter- and intraspecific variations

In this study we explore the inter- and intraspecific variations in the ecological stoichiometry of three dominant fish species [Saurida tumbil (n = 33), Pennahia macrocephalus (n = 34), and Upeneus sulphureus (n = 32)] from the Beibu Gulf, the contents of carbon (C), nitrogen (N), phosphorus (P), calcium (Ca), δ13C, and δ15N in fishes were analyzed. Results illustrated that the ranges of elemental variations (C, N, P, and Ca) in the three fishes were 36.73∼49.24%, 8.79∼13.99%, 1.11∼2.78%, and 1.16∼4.58%, respectively while P content varied the most, resulting in variations in C:P and N:P in fishes. Correlation analysis determined the association among various parameters and illustrated that Ca content was significantly positively correlated with P content, which indicated that P content variation was attributed to the formation of fish bones and scales. The C, N, and P contents and their ratios were significantly correlated with body length and δ13C in the three fishes, indicating that the changes in C:N:P concentrations are due to individual development and food sources. Significant inter- and intraspecific differences in the body stoichiometry of the three fishes were found in this study, mainly due to differences in body size and diet. The aquatic organisms underwent individual development fluctuations in morphology and diet, which consequently altered their stoichiometric features

Functional analysis of the structural domain of ARF proteins in rice (Oryza sativa L.)

Auxin response factors (ARFs) are key regulators of plant growth and development. Through interaction with auxin/indole acetic acid (Aux/IAA) proteins, they influence the expression of auxin response genes. An ARF gene family has been predicted in rice, but the functions of the individual structural domains of the OsARFs remain obscure. Bioinformatics was used to analyse the position of the DNA-binding domain (DBD), middle region (MR), and C-terminal dimerization domain (CTD) of OsARFs, and experimentally confirmed the presence of a classical monopartite nuclear localization signal (NLS) in the DBD. The DBD was shown to contribute to nuclear localization of OsARF proteins in addition to its known DNA-binding function. Interactions between 14 integrated OsARFs and 15 OsIAA proteins were tested using yeast two-hybrid assays. It was found that eight OsARF activators interacted with the 15 OsIAA proteins, while six OsARF repressors did not. The interactions between the MR+CTD or CTD of 10 OsARFs and 15 OsIAA proteins were also tested and the results were consistent with those of each intact OsARF, although some slight differences in interaction intensity were observed by α-galactosidase quantitative assays. The truncated CTD of OsARF11 did not interact with any OsIAA, implying that the CTD is required for ARF–IAA dimerization, and that the MR influences the interaction intensity in yeast. A subset of the interactions in yeast were also observed in tobacco plants using firefly luciferase complementation imaging assays, indicating that these interactions are specific in plants, and might have a special role in the auxin signalling response. This study provides new insight into the structure of OsARF proteins and ARF–Aux/IAA interactions