Search

Concerns over toxic nitrogenous disinfection byproducts (N-DBPs) necessitate identifying their precursors in source water. Natural organic amino compounds are known precursors to N-DBPs. Three Suwannee River (SR) standard reference materials (SRMs), humic acids (HA), fulvic acids (FA), and natural organic matter (NOM), are commonly used to study DBP formation, but the chemical makeup of amino compounds in SRSRMs remains largely unknown. To address this, we combined stable hydrogen/deuterium isotope labeling, HDPairFinder bioinformatics, and nontargeted high-performance liquid chromatography–high-resolution mass spectrometry (HPLC-HRMS) to characterize these compounds in SRSRMs. This method classifies reactive amines, provides accurate masses and MS/MS spectra, and quantifies intensities. We identified 2707 high-quality features with primary and/or secondary amines in SRSRMs and 75% of them having an m/z< 300. Across all three SRSRMs, 327 amino features were detected, while 856, 794, and 200 unique features were found in SRNOM, SRHA, and SRFA, respectively. In North Saskatchewan River (NSR) samples, a total of 6449 amino features were detected, 818 of them matched those in SRSRMs, and 87% of them were different between the two rivers. Using chemical standards, we confirmed 10 compounds and tentatively identified 5 more. This study highlights similarities and differences in reactive N-precursors in SRSRMs and local river water, enhancing the understanding of geo-differences in reactive N-precursors in different source waters.

Sucrose nonfermenting-related protein kinase 1 (SnRK1) is one of the critical serine/threonine protein kinases. It commonly mediates plant growth and development, cross-talks with metabolism processes and physiological responses to biotic or abiotic stresses. It plays a key role in distributing carbohydrates and sugar signal transporting. In the present study, eight SnRK1 coding genes were identified in sorghum (Sorghum bicolorL.) viasequences alignment, with three for α subunits (SnRK1α1to SnRK1α3), three for β (SnRK1β1to SnRK1β3), and one for both γ (SnRK1γ) and βγ (SnRK1βγ). These eight corresponding genes located on five chromosomes (Chr) of Chr1–3, Chr7, and Chr9 and presented collinearities to SnRK1s from maize and rice, exhibiting highly conserved domains within the same subunits from the three kinds of cereals. Expression results viaqRT-PCR showed that different coding genes of SnRK1sin sorghum possessed similar expression patterns except for SnRK1α3with a low expression level in grains and SnRK1β2with a relatively high expression level in inflorescences. Results of subcellular localization in sorghum leaf protoplast showed that SnRK1α1/α2/α3/γ mainly located on organelles, while the rest four of SnRK1β1/β2/β3/βγ located on both membranes and some organelles. Besides, three combinations were discovered among eight SnRK1 subunits in sorghum through yeast two hybrid, including α1-β2-βγ, α2-β3-γ, and α3-β3-γ. These results provide informative references for the following functional dissection of SnRK1 subunits in sorghum.

Iodinated aromatic disinfection byproducts (I-DBPs) are a group of nonregulated but highly toxic DBPs. The formation of I-DBPs is attributed mainly to HOI because it is the most abundant reactive iodine species in chloraminated water. In this study, we used computational modeling of thermodynamics to examine the mechanism of iodination of aromatic contaminants, e.g., dipeptides and phenols. Computational prediction of the energy barriers of the formation of iodinated tyrosylglycine (I-Tyr-Gly) (66.9 kcal mol–1) and hydroxylated Tyr-Gly (OH-Tyr-Gly) (46.0 kcal mol–1) via iodination with HOI favors the formation of OH-Tyr-Gly over I-Tyr-Gly. Unexpectedly, mass spectrometry experiments detected I-Tyr-Gly but not OH-Tyr-Gly, suggesting that I-Tyr-Gly formation cannot be attributed to HOI alone. To clarify this result, we examined the thermodynamic role of the most reactive iodine species H2OI+in the formation of aromatic I-DBPs under chloramination. Computational modeling of thermodynamic results shows that the formation of a loosely bonded complex of aromatic compounds with H2OI+is the key step to initiate the iodination process. When H2OI+serves as an acid catalyst and an iodinating agent, with HOI or H2O acting as a proton acceptor, the energy barrier of I-DBP formation was significantly lower (10.8–13.1 kcal mol–1). Therefore, even with its low concentration, H2OI+can be involved in the formation of I-DBPs. These results provide insight into the mechanisms of aromatic I-DBP formation and important information for guiding research toward controlling I-DBPs in drinking water.

N-Nitrosamine disinfection byproducts (DBPs) are a health concern because they are probable human carcinogens. Complex organic nitrogenous compounds, nitrosamine precursors, are largely unidentified in source water. Using stable isotopic labeling-enhanced nontargeted analysis, we identified a natural product N-heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCCA) in source water. Interestingly, we discovered that chloramination of MTCCA-containing water could produce four nitrosamines: methylethylnitrosamine, N-nitrosopyrrolidine, N-nitrosoanatabine, and N-nitrosoanabasine. Computational modeling and experimental results helped explain potential pathways of nitrosamines generated from chloramination of MTCCA. Further investigations confirmed widespread occurrence of MTCCA in source water and wastewater. Its concentration ranged from high in upstream creeks (23.2–332.2 ng L–1) to low in the river (5.7–37.6 ng L–1) during the 2020 spring runoffs, indicating that sources of MTCCA came from creeks around farms. Analysis of wastewater before and after ultraviolet, as well as microfiltration with subsequent ozonation treatments, showed increased MTCCA after treatments, demonstrating a difficulty to degrade and remove MTCCA in water. This study discovered the extensive presence of MTCCA in source water and wastewater, suggesting that natural N-heterocyclic compounds may serve as a new source of nitrosamine precursors.

The e antigen of hepatitis B (HBeAg) is positively associated with an increased risk of developing liver cancer and cirrhosis in chronic hepatitis B (CHB) patients. Clinical monitoring of HBeAg provides guidance to the treatment of CHB and the assessment of disease progression. We describe here an affinity binding assay for HBeAg, which takes advantage of G-quadruplex aptamers for enhanced binding and stability. We demonstrate a strategy to improve the binding affinity of aptamers by modifying their sequences upon their G-quadruplex and secondary structures. On the basis of predicting a stable G-quadruplex and a secondary structure, we truncated 19 nucleotides (nt) from the primer regions of an 80-nt aptamer, and the resulting 61-nt aptamer enhanced binding affinity by 19 times (Kd= 1.2 nM). We mutated a second aptamer (40 nt) in one loop region and incorporated pyrrolo-deoxycytidine to replace deoxycytidine in another loop. The modified 40-nt aptamer, with a stable G-quadruplex and two modified loops, exhibited a 100 times higher binding affinity for HBeAg (Kd= 0.4 nM) than the unmodified original aptamer. Using the two newly modified aptamers, one serving as the capture and the other as the reporter, we have developed an improved sandwich binding assay for HBeAg. Analyses of HBeAg in serum samples (concentration ranging from 0.1 to 60 ng/mL) of 10 hepatitis B patients, showing consistent results with clinical tests, demonstrate a successful application of the aptamer modification strategy and the associated aptamer binding assay.

Halogenated amino acids and peptides are an emerging class of disinfection byproducts (DBPs), having been detected in drinking water and in washed food products. However, the toxicological significance of these emerging DBPs remains unclear. In this study, the cytotoxicity of eight halogenated tyrosyl compounds was investigated in Chinese hamster ovary (CHO) cells using real-time cell analysis (RTCA). Dihalogenated tyrosyl compounds are more cytotoxic than their monohalogenated analogues. The cytotoxicity of the dihalogenated compounds is associated with their ability to induce intracellular reactive oxygen species (ROS), suggesting that oxidative stress is an important toxicity pathway of these compounds. Pearson correlation analysis of the cytotoxicity (IC50values) of these compounds with eight physicochemical parameters showed strong associations with their lipophilicity (logP) and reactivity (polarizability, ELUMO). Finally, cytotoxicity testing of the concentrated extracts of a chloraminated mixture of eight dipeptides with bromide or iodide showed the cytotoxicity of these mixtures in the order: iodinated peptides > brominated peptides ≥ chlorinated peptides. These results demonstrate that halogenated peptide DBPs are toxicologically relevant, and further research is needed to understand the implications of long-term exposure for human health.

The RNA-guided CRISPR/Cas9 system is a powerful genome-editing technology with broad applications. Improving delivery efficiency and controllable activity of the CRISPR/Cas9 system is an area of intense research. We report the design, construction, and application of a CRISPR/Cas9 nanomachine (LACM), activated by a near-infrared (NIR) laser, which enables efficient delivery of single-guide RNA (sgRNA) into living cells and achieves controlled release of the sgRNA for the CRISPR/Cas9 activity. The LACM was constructed using a gold nanorod (AuNR) as a carrier that was decorated with dozens of protector DNAs stably hybridizing with the target binding domain of sgRNA. The DNA assembly on the AuNR protected the sgRNA. Irradiation with a NIR laser generated heat on the AuNR, resulting in controlled release of sgRNA, which guided the CRISPR/Cas9 genome editing. Successful editing of the EGFPand EMX1genes in A549 and HEK293T cells, as well as knocking down of the PLK1gene to induce apoptosis of the target cells, highlights the promising potential of the LACM for diverse applications.

The balance of blood CD8+CD28+/CD8+CD28−T cells has been verified to be vital for patients with ulcerative colitis (UC), but their role in inflammatory bowel disease (IBD) remains unknown. This investigation aimed to evaluate the efficiency of the balance in predicting the active stage in IBD patients.

High-resolution mass spectrometry (HRMS) is a prominent analytical tool that characterizes chlorinated disinfection byproducts (Cl-DBPs) in an unbiased manner. Due to the diversity of chemicals, complex background signals, and the inherent analytical fluctuations of HRMS, conventional isotopic pattern (37Cl/35Cl), mass defect, and direct molecular formula (MF) prediction are insufficient for accurate recognition of the diverse Cl-DBPs in real environmental samples. This work proposes a novel strategy to recognize Cl-containing chemicals based on machine learning. Our hierarchical machine learning framework has two random forest-based models: the first layer is a binary classifier to recognize Cl-containing chemicals, and the second layer is a multiclass classifier to annotate the number of Cl present. This model was trained using ∼1.4 million distinctive MFs from PubChem. Evaluated on over 14,000 unique MFs from NIST20, this machine learning model achieved 93.3% accuracy in recognizing Cl-containing MFs (Cl-MFs) and 92.9% accuracy in annotating the number of Cl for Cl-MFs. Furthermore, the trained model was integrated into ChloroDBPFinder, a standalone R package for the streamlined processing of LC-HRMS data and annotating both known and unknown Cl-containing compounds. Tested on existing Cl-DBP data sets related to aspartame chlorination in tap water, our ChloroDBPFinder efficiently extracted 159 Cl-containing DBP features and tentatively annotated the structures of 10 Cl-DBPs via molecular networking. In another application of a chlorinated humic substance, ChloroDBPFinder extracted 79 high-quality Cl-DBPs and tentatively annotated six compounds. In summary, our proposed machine learning strategy and the developed ChloroDBPFinder provide an advanced solution to identifying Cl-containing compounds in nontargeted analysis of water samples. It is freely available on GitHub (https://github.com/HuanLab/ChloroDBPFinder).

We report a new combinatorial approach of stable isotopic labeling (SIL)–solid phase extraction (SPE)–liquid chromatography–tandem high-resolution mass spectrometry (LC–HRMS/MS) for identification of amino-containing contaminants at trace levels in source water. The new SIL method requires small amounts of formaldehyde (CH2O) and deuterated formaldehyde (CD2O) to efficiently label ng/L amino compounds in 1 L of water and improves SPE recovery, enabling environmental analysis of trace amino-compounds. Isotopically methylated components were confirmed using LC–MS/MS based on their retention times, and characteristic isotope patterns of the molecular and product ions. Using the characteristic isotope patterns, we established a data prioritization process to identify the amino compounds in thousands of mass peaks in raw data. Analysis of a labeled authentic source water detected 8952 m/zpeaks and tentatively identified 154 amino compounds. Our SIL-methylation prioritization approach effectively reduced the complexity of data. Manual spectrum interpretation identified 77 of the 154 components as amino acids and peptides. We confirmed 8 of the 77 compounds using commercially available standards to demonstrate the feasibility and reliability of our SIL–SPE–LC–HRMS/MS method for environmental analysis of trace amino-containing contaminants. The method can efficiently identify amino-precursors in source water, enabling other studies of nitrogenous disinfection byproduct formation.

Homoepitaxial growths of 4H-SiC were performed on Si-face (0001) on-axis substrates in a SiH4-C2H4-H2-HCl system by using our home-made vertical hot wall CVD reactor. The influence mechanism of the growth temperature and C/Si ratio on the morphology and growth rate was studied. It is found that the steps in the epilayer become more clear with the increasing temperatures. The result indicates that the C/Si ratio window of on-axis epitaxial growth is very narrow. Only when the C/Si ratio was 1.2, a slightly improved surface morphology can be achieved. The results indicate that 4H-SiC epitaxial layers were obtained on on-axis substrates and the films were highly-oriented 4H-SiC.

The resonant frequency and Q factor of the SiC microcantilever were theoretically analyzed and calculated based on the stereotyped basic theories of the cantilever beam, and the relationship between the vibration mode and structure geometries was also simulated. Modal analysis by means of finite element method was performed on millimeter-, micron-and nanoscale microcantilevers, and the results showed that the smaller the microstructure was, the higher the resonant frequency can be obtained. The Q factor can be extracted from hamonic spectra after modal analysis, and the amplitude of Q factor was about 105. This paper shows that SiC epitaxial layers have great potential in microcantilevers.

Dipeptides are widely present in surface water and serve as precursors to form disinfection byproducts (DBPs) during disinfection (e.g., chloramination). Bromide (Br–) and iodide (I–) are common in many source waters, enhancing Br- and I-DBP formation. Recently Cl-, I-, and Cl-I-dipeptides were identified after chloramination of tyrosyl dipeptides in the presence of I–and were detected in authentic disinfected drinking water samples. However, the formation and occurrence of Br- and mixed halogen (Cl, Br, and/or I)-dipeptides in disinfected water have not been studied. Here we investigated the formation of halogenated dipeptides from three aromatic dipeptides, phenylalanylglycine (Phe-Gly), tyrosylalanine (Tyr-Ala), and tyrosylglycine (Tyr-Gly), under chloramination in the presence of Br–and I–at environmentally relevant levels ([Br–] and [I–], 0 and 0 μg L–1, 6 and 30 μg L–1, 30 and 30 μg L–1, 150 and 30 μg L–1, 300 and 30 μg L–1, and 900 and 30 μg L–1, respectively). For the first time, N-Br- and N,N-di-Br- as well as N-Br-N-Cl- and N-Br-3-I-tyrosyl dipeptides were identified using infusion electrospray quadrupole time-of-flight mass spectrometry. Tyrosyl dipeptides produced N-Cl-, 3-I-/3,5-di-I-, and N-Cl-3-I-tyrosyl dipeptides, while Phe-Gly formed only N-Cl-/N,N-di-Cl-Phe-Gly. To determine halogenated dipeptides in authentic water samples, we developed a new method of solid phase extraction and high-performance liquid chromatography with quadrupole ion trap mass spectrometry using reaction monitoring. 3,5-Di-I-Tyr-Ala and N-Br-Tyr-Ala were detected in treated water but not in the corresponding raw water, warranting further investigation into the occurrence of halogenated peptides in other drinking water systems.

There is increasing literature evidence both clinically and experimentally on the existence of potent, adaptive interactions between the central and peripheral aspects of the neuroimmune system in the genesis and maintenance of chronic neuropathic extremity pain and nociceptive back pain. The neuroinflammatory pathways are modulated by the interaction of pro‐ and anti‐inflammatory cytokines and chemokines, which are released by peripheral immune system‐derived cell species (macrophages and leukocytes). This review examines the possible impact of spinal and peripheral neurostimulation on the inflammatory response in the context of acute and chronic pain pathologies of different origin. A narrative review of preclinical and clinical studies addressed to the spinal cord and peripheral nerve stimulation and neuroinflammation. Available literature was reviewed on neurostimulation technologies and both acute and chronic low‐grade inflammation to identify primary outcome measures and to provide an overview of postulated mechanisms of action of neurostimulation on host inflammatory responses. Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, SCOPUS, and manual searches of the bibliographies of known primary and review articles. A comprehensive review of the literature indicates an alternate or synergistic mechanism of action of neurostimulation, beyond modulating somatosensory pain pathways, in modifying inflammatory response associated with chronic pain, by promoting a systemic anti‐inflammatory state with upregulation of anti‐inflammatory mediators. These preliminary findings may have important implications on the potential applications of neurostimulation as an anti‐inflammatory therapy and the role of molecular profiling as a preimplant screening modality and post‐implant outcome validation. Thus, future targeted clinical and experimental research is highly warranted in this particular novel field of neuromodulation.

We report a new material of a composite silica monolith nested in sponge (SiMNS) and demonstrate an application in the trace analysis of environmental contaminants in water. SiMNS is prepared through sponge absorption of a hydrolyzed mixture of siloxanes and in situ gel formation within the pores. Images obtained using scanning electron microscopy show that the silica and sponge skeletons are mutually nested in SiMNS. This nested composite structure of SiMNS enhances the mechanical flexibility of the material, allowing for reproducible production of desirable sizes and shapes for solid phase extraction (SPE) cartridges without the need to use frits. Functionalization of SiMNS provides appropriate SPE options for selective and efficient extraction of specific contaminants. SPE cartridges packed with functionalized SiMNS–SO3Na have high extraction capacity, good stability in the pH range of 2 to 11, and efficient enrichment of dipeptides in water. Extraction of six dipeptides from water using these new SiMNS–SO3Na SPE cartridges followed by HPLC-MS/MS analysis results in improved method detection limits (MDLs) of 0.02–1.3 ng/L and method quantification limits (MQLs) of 0.05–4.3 ng/L. Successful identification and quantification of three dipeptides, Tyr–Gly, Phe–Gly, and Tyr–Ala, from raw water demonstrates a useful application of the new SPE materials for environmental analysis of trace contaminants. On the basis of this work, a range of functionalized SiMNS materials can be produced and tailored for various environmental and exposomic analyses.

The developmental toxicity of water disinfection byproducts remains unclear. Here we report the study of halobenzoquinone (HBQ)-induced in vivo developmental toxicity and oxidative stress using zebrafish embryos as a model. Embryos were exposed to 0.5–10 μM of individual HBQs and 0.5–5 mM haloacetic acids for up to 120 h postfertilization (hpf). LC50values of the HBQs at 24 hpf were 4.6–9.8 μM, while those of three haloacetic acids were up to 200 times higher at 1900–2600 μM. HBQ exposure resulted in significant developmental malformations in larvae, including failed inflation of the gas bladder, heart malformations, and curved spines. An increase in reactive oxygen species was observed, together with a decrease in superoxide dismutase activity and glutathione content. Additionally, the antioxidant N-acetyl-l-cysteine significantly mitigated all HBQ-induced effects, supporting that oxidative stress contributes to HBQ toxicity. Further experiments examined HBQ-induced effects on DNA and genes. HBQ exposure increased 8-hydroxydeoxyguanosine levels, DNA fragmentation, and apoptosis in larvae, with apoptosis induction related to changes in the gene expression of p53and mdm2. These results suggest that HBQs are acutely toxic, causing oxidative damage and developmental toxicity to zebrafish larvae.

Burst spinal cord stimulation (SCS) technology uses a novel waveform that consists of closely packed high‐frequency electrical impulses followed by a quiescent period. Within the growing field of neuromodulation, burst stimulation is unique in that it mimics the natural burst firing of the nervous system, in particular the thalamo‐cingulate rhythmicity, resulting in modulation of the affective and attentional components of pain processing (e.g., medial thalamic pathways). A review of preclinical and clinical studies regarding burst SCS for various chronic pain states. Available literature was reviewed on burst stimulation technology. Data sources included relevant literature identified through searches of PubMed, MEDLINE/OVID, SCOPUS, and manual searches of the bibliographies of known primary and review articles. The primary outcome measure was to understand the mechanisms of action with regards to burst stimulation and to review clinical data on the indications of burst SCS for various chronic pain states. We present both mechanisms of action and review uses of burst stimulation for various pain states. Burst stimulation offers a novel pain reduction tool with the absence of uncomfortable paresthesia for failed back surgery syndrome, diabetic neuropathic pain, and anesthesia dolorosa. Preclinical models have emphasized that the potential mechanisms for burst therapy could be related to neural coding algorithms that mimic the natural nervous system firing patterns, resulting in effects on both the medial and lateral pain pathways. Other mechanisms include frequency dependent opioid release, modulation of the pain gate, and activation of electrical and chemical synapses.

Halobenzoquinones (HBQs) are emerging disinfection byproducts (DBPs) that effectively induce reactive oxygen species and oxidative damage in vitro. However, the impacts of HBQs on oxidative-stress-related gene expression have not been investigated. In this study, we examined alterations in the expression of 44 genes related to oxidative-stress-induced signaling pathways in human uroepithelial cells (SV-HUC-1) upon exposure to six HBQs. The results show the structure-dependent effects of HBQs on the studied gene expression. After 2 h of exposure, the expression levels of 9 to 28 genes were altered, while after 8 h of exposure, the expression levels of 29 to 31 genes were altered. Four genes (HMOX1, NQO1, PTGS2, and TXNRD1) were significantly upregulated by all six HBQs at both exposure time points. Ingenuity pathway analysis revealed that the Nrf2 pathway was significantly responsive to HBQ exposure. Other canonical pathways responsive to HBQ exposure included GSH redox reductions, superoxide radical degradation, and xenobiotic metabolism signaling. This study has demonstrated that HBQs significantly alter the gene expression of oxidative-stress-related signaling pathways and contributes to the understanding of HBQ-DBP-associated toxicity.

Iodinated disinfection byproducts (I-DBPs) are highly toxic, but few precursors of I-DBPs have been investigated. Tyrosine-containing biomolecules are ubiquitous in surface water. Here we investigated the formation of I-DBPs from the chloramination of seven tyrosyl dipeptides (tyrosylglycine, tyrosylalanine, tyrosylvaline, tyrosylhistidine, tyrosylglutamine, tyrosylglutamic acid, and tyrosylphenylalanine) in the presence of potassium iodide. High resolution mass spectrometry and tandem mass spectrometry (MS/MS) analyses of the benchtop reaction solutions found that all seven precursors formed both I- and Cl-substituted tyrosyl dipeptide products. Iodine substitutions occurred on the 3- and 3,5-positions of the tyrosyl-phenol ring while chlorine substituted on the free amino group. To reach the needed sensitivity to detect iodinated tyrosyl dipeptides in authentic waters, we developed a high performance liquid chromatography (HPLC)-MS/MS method with multiple reaction monitoring mode and solid phase extraction. HPLC-MS/MS analysis of tap and corresponding raw water samples, collected from three cities, identified four iodinated peptides, 3-I-/3,5-di-I-Tyr-Ala and 3-I-/3,5-di-I-Tyr-Gly, in the tap waters but not in the raw waters. The corresponding precursors, Tyr-Ala and Tyr-Gly, were also detected in the same tap and raw water samples. This study demonstrates that iodinated dipeptides exist as DBPs in drinking water.

This work presents theoretical demonstration of two-dimensional electron gas (2DEG) at the interface between Al0.2Ga0.8N and 4H-SiC, based on the self-consistent solution of Schrödinger–Poisson equations. High sheet carrier density of 1.1×1013 cm-2 was obtained in the Al0.2Ga0.8N/4H-SiC heterostructure, which is comparable to the electron concentration in Al0.2Ga0.8N/GaN heterostructure. The current–voltage characteristics of a high-electron-mobility transistor (HEMT), based on the Al0.2Ga0.8N/4H-SiC heterostructure, show a saturated drain current of 1.5 A/mm at the gate voltage of 2 V and the transconductance of 194 mS/mm at -3.95 V. In spite of interface-roughness scattering and phonon scattering, the 2DEG at the AlxGa1-xN/4H-SiC interface exhibits high electron mobility values of 3365 cm2/ (V·s) at 77K and 1120 cm2/ (V·s) at 300K. These results indicate that AlxGa1-xN/4H-SiC heterostructure can significantly improve the mobility of SiC based power switching devices.

Aspartame (APM), a dipeptide of aspartic acid (ASP) and phenylalanine (PHE), is a widely used artificial sweetener in beverages. It is unclear whether residual chlorine in tap water can react with APM to form disinfection byproducts (DBPs). Therefore, we investigated the formation of DBPs from the reaction of APM with residual chlorine in authentic tap water. APM and a commercial sweetener (CS) packet containing APM were studied under authentic and simulated tap water conditions. Eight chlorinated products of APM were detected using solid-phase extraction (SPE) and high performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS). These new chloro-products were tentatively identified based on accurate masses, isotopic patterns of 35,37Cl, and MS/MS spectra. Furthermore, we identified APM as a precursor to 2,6-dichloro-1,4-benzoquinone (DCBQ). DCBQ significantly increased to 2.3–12 ng/L with the addition of APM or CS in tap waters collected from different locations compared to 1.4–1.8 ng/L in the same tap water samples without sweetener. DCBQ and two of the chlorinated transformation products were identified in cold prepared tea containing APM. DCBQ formation was eliminated when the residual chlorine in tap water was reduced by ascorbic acid or boiling prior to the addition of APM or CS. This study found that eight new DBPs and DCBQ were produced by the reactions of residual chlorine with APM and CS. These findings show an unintended exposure source of emerging DBPs via APM sweetened beverages.

The onset of spring runoff in northern climates and tap water odor events are difficult to predict because common water quality parameters cannot fully explain the intermittent odor events that occurred over past decades. Studies have shown that small polar water-soluble compounds, such as amino acids (AAs), leach first from ice/snowmelt. AAs are known to produce odorous compounds, such as aldehydes and chloroaldimines, upon chlorination. Therefore, we proposed that AAs may serve as markers for small and soluble organics that contribute to the odor of chlorinated tap water. Here, we studied the occurrence of AAs in source water collected at two water treatment plants and the odor profiles of tap water at >300 homes during the 2021 and 2022 spring runoff events. AA concentrations were at baseline levels (<100 ng/L) during the 2021 runoff but much higher (up to 5500 ng/L) in 2022 and associated with an escalation in odor complaints. AA concentrations peaked at the onset of the 2022 spring runoff and corresponded with the strongest reported odor intensities in tap water. We obtained high resolution MS and MS/MS spectra of chloroaldimines and confirmed the formation of chloroaldimines under chlorination of the six AAs detected in source water. The results indicate that AAs signal the onset of spring runoff and represent small polar water-soluble compounds that may contribute to tap water odor problems.

In this study, we developed a micellar platform composed of terpolymers for the encapsulation of inorganic arsenite or arsenous acid (AsIII). For this purpose, a series of terpolymers composed of poly(ethylene oxide) (PEO, block A), poly(α-carboxylate-ε-carprolactone) (PCCL, block B), and poly(ε-caprolactone) (PCL, block C) with either a blocked, i.e., BCor CB, or random, i.e., (B/C)ranblock copolymer sequence in the polyester segment was synthesized. The COOH groups on block Bwere further modified with mercaptohexylamine for AsIIIencapsulation. We then investigated how sequence of terpolymers can affect the stability and surface charge of micelles as well as the cellular uptake of their cargo, i.e., AsIII, by MDA-MB-435 cancer cells. 1H NMR spectroscopy in D2O and CDCl3was also used to study the structure of different terpolymer micelles. Our results showed micelles with ABCsequence to have better stability over those of ACBand A(B/C)ranas reflected by a lower critical micellar concentration. The AsIII-loaded ABCmicelles were less negatively charged on the surface than the other two types of terpolymer micelles. In line with this observation, ABCmicelles showed a substantially enhanced uptake of AsIIIby MDA-MB-435 cancer cells. Stability and surface charge are key parameters that can influence the performance of polymeric micelles as nanodrug carriers. Based on these results, we suggest ABCmicelles to have improved characteristics for AsIIIdelivery compared to ACBand A(B/C)ranmicelles.

Haematological diseases with pancreatic masses as the first symptom are clinically rare but should not be ignored. This case report describes a 60-year-old female patient with acute leukaemia that had a pancreatic mass as her first symptom. The patient was admitted and elastography combined with endoscopic ultrasound (EUS) guided fine needle aspiration biopsy (EUS-FNA) was used for diagnosis, treatment planning and determination of prognosis. The site selected for the EUS-FNA puncture was the caudal section of the pancreatic body and the posterior wall of the gastric body was used as the puncture point. The elastography view of the head of the pancreas was blue/green with predominant blue colour. A 19 G puncture needle with a slow-draw core and two stitches of micro-negative pressure were used. Cytology detected heterotypic cells, pancreatic puncture histopathology, the presence of pancreatic alveolar structures and heterotypic tumour cells in the interstitium. Immunohistochemistry of the pancreatic puncture tissue showed B-cell lymphoblast-derived tumours and bone marrow puncture indicated acute lymphoblastic leukaemia. The patient was diagnosed with acute lymphoblastic leukaemia invading the pancreas and was treated with chemotherapy. After treatment, her condition was stable. Follow-up is ongoing and there have been no signs of tumour recurrence or metastasis.

Electron beam irradiation is a chemical technology which mainly applies to food irradiation preservation, radiation sterilization of medical supplies, radiation chemistry and so on. It can change the molecular structure by using the radioactive radiation. In this present study, soybean protein concentrate powder was treated by electron beam irradiation to investigate its effects on the DH, the peptide antioxidant activity and the microcosmic surface morphology. The results indicated that the electron beam irradiation did not have effect on the DH. However, the peptide antioxidant activity significantly increased when increasing the irradiation dose. The highest peptide antioxidant activity 56.84 % was obtained at 3.24 kGy. Scanning electron microscope (SEM) revealed that there were a number of changes to the microcosmic surface morphology after the electron beam irradiation. Not only the shape of the soybean protein concentrate powder particles was changed, but the surface state was changed as well.

The intensities of the dipole, quadrupole and octupole modes for gold nanoshells have been investigated with various dielectric constants for the embedding medium and with various sizes of the nanoshells by means of Mie theory. With the increase in the dielectric constant of embedding medium, it is found that the intensities of all modes become stronger first, and then the higher mode starts to become weak. We also observe with decreasing the core size of a nanoshell with a fixed outer radius, a larger dielectric constant for the embedding medium is needed corresponding to the change of higher mode intensities from stronger to weaker. We have ascribed the changes of the dipole, quadrupole and octupole modes to the competition among the variations of induced surface charges, conduction electrons and oscillation electrons.

The influence of the optical properties of the core and shell materials on the LSPR strength for nanoshell particles are calculated based on the quasi-static functions. The results show that for particles with the metallic shell and gained core, the desired real and imaginary parts of dielectric function are positive and negative respectively, and both the absolute values increase as the volume fraction of shell material increases while the LSPR strength is strongest. For particles with metallic material core and gained material shell, in order to produce the maximum LSPR strength, gain medium can have two kinds of choices, one is that the real part of the dielectric function is positive and the imaginary part is negative and both the absolute values are relatively large, the other is the real part and imaginary part of gained dielectric function are negative and their absolute values are relatively small, which small change may lead to mobile resonance wavelength greatly.

Nomex (Aramid 1313) is the best high temperature resistant high-tech new materials in the world today. In this paper, Nomex was treated in the experiment of high temperature, low temperature, high and low temperature conditions. The results show that the high temperature affects the strength and breaking elongation for nomex fiber. Low temperature and high & low temperature cycle does not affect much on the strength and breaking elongation.

We report a real-time cell-electronic sensing (RT-CES) technique using the T24 bladder cancer cell line as a probe to analyze the comparative cytotoxicity of water contaminants. The RT-CES system consists of a 96-well E-plate embedded with microelectrodes in each micro-well. As T24 cells grow on the surface of the microelectrodes, the impedance between the cell-microelectrodes continuously increases with increasing cell number. When the cells are exposed to a chemical, the toxic effects on the cells resulting in cell death, detachment, and morphological changes reduce impedance. These dynamic changes are continuously monitored to provide real-time detection of cell responses. This method was successfully applied to analyze the cytotoxic characteristics of four halobenzoquinones (HBQs), emerging disinfection byproducts in drinking water, 2,6-dichloro-1,4-benzoquinone (DCBQ), 2,6-dichloro-3-methyl-1,4-benzoquinone (DCMBQ), 2,3,6-trichloro-1,4-benzoquinone (TCBQ), and 2,6-dibromobenzoquinone (DBBQ). T24 cells were seeded in each of the 96 microwells on the 96-E-plate, and treated with varying concentrations of the four HBQs. The RT-CES technique provides continuous profiles of HBQ induced cytotoxic responses and temporal IC50histograms in T24 cells, demonstrating concentration-, time- and compound-dependent cytotoxic effects. These results enable ranking of cytotoxicity of the four HBQs: DCBQ > DBBQ > DCMBQ > TCBQ. We further examined and compared the cytotoxicity of HBQs using the conventional neutral red uptake (NRU) and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays, to complement the RT-CES data. The 24 h IC50values of HBQs obtained from RT-CES correlated with those from the NRU assay (R2= 0.9480, P< 0.05), while MTS results presented moderate and less consistent correlation with the results of the RT-CES and NRU (R2= 0.5281 and 0.3144, respectively). All three assays show that DCBQ causes greater toxic effects on T24 than the other three HBQs, although the IC50values are dependent on the assays. The RT-CES technique can provide sensitive and high-throughput testing of cytotoxicity of environmental contaminants.

Wood plastic composite (WPC) in this study was made from high density polyethylene (DHPE) or low density polyethylene (LDPE) with different species wood flour using extrusion. Ethylene vinyl acetate (EVA) was used to improve the weathering resistance performance of WPC. Degradation test and ageing test were employed to study the weathering stability of WPC modified by EVA. The results show that EVA can improve the ageing resistant performance of WPC and have no significant effect on the degradation resistant performance of WPC. It suggests that EVA can be used to improve the weathering resistance performance of WPC.

In this paper, BaZrO3, which is successfully used to prepare the YBCO single crystal superconductor, is introduced into the melting of titanium alloys. The density of the home-made BaZrO3 crucible reaches 97% of theoretical density, and TiNi alloy is melted using this crucible by the vacuum induction method. It is found that the home-made BaZrO3 crucible possesses excellent thermal shock resistance. After melting, the surface of the ingot is smooth and it can be separated from the crucible easily, there is no reaction layer and elemental diffusion between the refractory and the melt is not observed, the oxygen content of the melt is about 600 ppm, and the increase of other impurity elements (i.e., Ba, Zr) is negligible. This implies that the BaZrO3 is a promising candidate for refractories for melting the TiNi alloy.

We have studied the defects on 4H-SiC substrates and epilayers by using molten KOH defect selective etching. It is found that adding Na2O2 into molten KOH at the etched temperature enables the revelation of dislocations on n+ and semi-insulating substrates, whereas purely molten KOH is sufficient to obtain good etched pattern on p+ substrates. Related statistical data on dislocation densities of n+, p+ and semi-insulating substrates are also presented. The morphological defects commonly observed on the epilayers are finally investigated and it is shown that some important structural features can be revealed by molten KOH method.

The emergency response ability plays a decisive role in the railway dispatching emergency disposal process and the evaluation of response ability is particularly important. Based on the establishment of evaluation system, the evaluation of response ability to dispatching emergency by interval number theory of uncertainty in mathematics was studied. With using [0,1] interval evaluation and taking three mean value to calculate index attribute and using weight method, the paper establishes the evaluation method of response ability to dispatching emergency. At last, taking the evaluation response ability to dispatching emergency of Shanghai Railway Bureau as example, it is proved that the proposed method is effective, simple and feasible. The new evaluation model would provide the reference for improving level of railway dispatching emergency disposal.

Removal the pollutants of the polluted water through flotation bio-film are reached by the cooperation work of microbial degradation and sand filter. This paper through dosing the bacterial suspension and nutrition did the research on biofilm accretion. Results showed that the biomass on quartz sand had greatly increased, and the removal rates of organic and ammonia nitrogen also had a huge increase. At the end of biofilm accretion, the removal rates of pollutants keep at a stable value.

The evaluation of train operation plan is the important means of optimizing train operation plan. It is also a complex multi index comprehensive evaluation problem. Based on comparison of angle cosine value between line segment in each scheme and ideal line segment in ideal scheme, cosine decisions get the optimal decision scheme. Through the main factor analysis of intercity railway train plan and by combining the entropy weight coefficient method and using the cosine decision method the evaluation of index system of intercity railway train plan is established. Taking the Shanghai-Nanjing intercity railway for example, the results shows that cosine decision is adapt to the actual operation with simple calculation process, easy to use. The evaluation model should provide new ideas and methods for the optimization the train operation plan so as to provide technical support for intercity railway operation.

In the environment of network competition, it is a basic condition of stabilized operation to measure effectively the risk with early warning of the project of material supply chain system. From the angle of system, this paper analyzes the set of risk factors of the project of material supply chain, and provides a fuzzy method for the supply chain whole risk of measures. Making use of this method, we can acquire the valid early warning of the system risk of project of material supply chain, so as to solve the disadvantage of deviating between the risk analysis of system and node of the project of material supply chain, all which has profit to the risk managements of system effect of the project of material supply chain and the choice of cooperation contract company.

A vertical 3×2〞low pressure chemical vapor deposition (LPCVD) system has been developed to realize fast epitaxial growth of 4H-SiC. The epitaxial growth process was optimized and it was found that the growth rate increases with increasing C/Si ratio and tends to saturate when C/Si ratio exceeded 1. Mirror-like thick 4H-SiC homoepitaxial layers are obtained at 1500 ℃ and C/Si ratio of 0.5 with a growth rate of 25 μm/h. The minimum RMS roughness is 0.20 nm and the FWHM of rocking curves of epilayers grown for 1 hour and 2 hours are 26.2 arcsec and 32.4 arcsec, respectively. These results indicate that high-quality thick 4H-SiC epilayers can be grown successfully on the off-orientation 4H-SiC substrates.

In this study, Ni-P-SiC composite coatings were prepared by adding different amount of SiC particles into electroless Ni-P plating solution. The effects of SiC particles concentration in solution on depositing rate and composition of the coatings were investigated. The different SiC contents in coatings could be obtained by adjusting the amount of SiC particle concentration in electroless plating solution. Scanning electron microscopy (SEM) results indicate that SiC particles are dispersed in the composite coating and Ni-P alloy is mainly as a bond metal envelope with SiC particles. At the same time, the microhardness became increased and the wear resistance improved with the increasing of SiC content.

The concept of vectorial nonparaxial cosh-squared-Gaussian (ChsG) beams is introduced and their free space propagation equations are derived analytically by using the vectorial Rayleigh-Sommerfeld diffraction integrals, and far-field expressions as well as paraxial propagation formula are obtained in free space. Numerical calculations and analysis show that, the f-parameter and decentered parameter plays an important role in determining the far-field properties of the vectorial nonparaxial ChsG beams.

Polymer-dispersed liquid crystals are one kind of important devices. With a He-Ne laser and a photoelectric detector, we measured the driving-voltage dependent and viewing-angle dependent transmission for a polymer-dispersed liquid crystal device. Our results showed that the polymer-dispersed liquid crystal device worked at the driving voltage of 4 V and the effective viewing angle of about 65 degree.

Cobblestone-like CoSb3 nanoparticle films have been achieved via a catalyst-free vapor transport growth technique. The thermoelectric properties of the nanoparticle films were measured from room temperature to around 500 oC. The resultant CoSb3 nanoparticle films show high electrical conductivities due to clean particle surfaces. A maximum power factor reaches 1.848×10-4 W/mK2 at 440 oC. The discussed approach is promising for realizing new types of highly efficient thermoelectric semiconductors.

This paper presents a deep research on 2-DOF planar parallel mechanism during developing a new type of hybrid machine tool. The composition of this planar parallel mechanism is introduced, its direct and inverse kinematics solution equations as well as the solution equations for the speed and the acceleration are deduced, meanwhile, the jacobian matrix is obtained. The statics problems of the parallel mechanism are modeled and analyzed based on principle of virtual work, and the balancing driving force solution equation of the driving part is given. Through the solving process we can see that the direct and inverse solution equations of this mechanism have explicit expressions and convenient to realize real-time control. It forms a solid basis for the design and development of this mechanism.

In order to reduce the fault detection rate and improve the self-adaptive capability in network fault detection, an artificial immune mechanism which is inspired by multi-layer defense of a biological immune system is proposed to perform network fault detection. The immune model is composed of three parts: the inherent detection layer, fuzzy judgment layer and adaptive detection layer. Dendritic cells can influence the reaction of coordinating T-cells, which can be activate or tolerate so that induce adaptive immune responses and affirm the type of adaptive response. Inherent detection layer and fuzzy judgment layer interact with each other to reduce the error detection rate, while the adaptive detection layer is capable of learning unknown fault patterns.

The curing process of tetrabromo-bisphenol-A epoxy resin (TBBPAER) with 4,4´-diaminodiphenylsulfone (DDS) was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and torsional braid analysis (TBA) methods. FTIR results indicated that the maximum reaction velocity was observed at initial stages at higher temperature, but it was occurred at conversion =10 - 40 % at lower temperature. It showed that there is the crossover from the autocatalytic model to the nth-order mechanism when the temperature was increased. While the double glass transition temperatures occuring in the system, according to the microstructure of the reactant, a theoretical and reasonable explanation may arise from this article.

Abstract: How to extract optimal composite attributes from a variety of conventional seismic attributes to detect reservoir features is a reservoir predication key, which is usually solved by reducing dimensionality. Principle component analysis (PCA) is the most widely-used linear dimensionality reduction method at present. However, the relationships between seismic attributes and reservoir features are non-linear, so seismic attribute dimensionality reduction based on linear transforms can’t solve non-linear problems well, reducing reservoir prediction precision. As a new non-linear learning method, manifold learning supplies a new method for seismic attribute analysis. It can discover the intrinsic features and rules hidden in the data by computing low-dimensional, neighborhood-preserving embeddings of high-dimensional inputs. In this paper, we try to extract seismic attributes using locally linear embedding (LLE), realizing inter-horizon attributes dimensionality reduction of 3D seismic data first and discuss the optimization of its key parameters. Combining model analysis and case studies, we compare the dimensionality reduction and clustering effects of LLE and PCA, both of which indicate that LLE can retain the intrinsic structure of the inputs. The composite attributes and clustering results based on LLE better characterize the distribution of sedimentary facies, reservoir, and even reservoir fluids.

The distributions of residual stresses for zinc-plated film were measured quantitatively by X-ray diffraction (XRD), its interfacial structures were observed with scanning electron microscope (SEM). The effects of residual stress on bonding strength of zinc-plated film were investigated, and its influence mechanism was discussed. The experimental results show that residual stresses of zinc-plated film are behaved as tensile stress, which increase with its thickness, bonding strength of zinc-plated film is inverse ratio with residual stresses; the effects of residual stress on film crack are obvious, tensile stress speeds film cracking, which decrease its bonding strength; bonding strength of zinc-plated film is increased by improving its residual stress distribution.

This study was designed to analyse the reliability of using urinary and blood trichloroacetic acid (TCAA) as a biomarker of exposure. A total of 46 healthy women consumed supplied TCAA-containing tap water for 15 days and provided urine and blood samples for TCAA measurements. The findings revealed that the reliability of measurements was excellent by using measures of TCAA ingestion, blood concentration and urinary excretion (intraclass correlation coefficients (ICC) > 0.75, p < 0.001). Volume of tap water consumption (ICC  0.69) and creatinine-adjusted urinary concentration (ICC  0.72) were less reliable. This indicated that the intraindividual variability was small and the interindividual reliability was high by using these measures in this cohort study. Laboratory variability did not significantly contribute to total variance (ICC > 0.95, p < 0.001). Other possible sources of variation such as bathing, showering, dishwashing and physical activities were unlikely to contribute significantly to total variance. For sampling strategies, 1-day blood sampling and 2-day urine sampling are sufficient to achieve reliability for an epidemiological study if a quasi-steady-state TCAA level in the body is reached. The results suggest that TCAA ingestion, TCAA loading in blood and urinary TCAA excretion are reliable measures for use as biomarkers in epidemiological studies.