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BACKGROUND Vascular injury initiates rapid platelet activation which is critical for hemostasis, while it also cause fatal thrombotic diseases, such as myocardial infarction or ischemic stroke. OBJECTIVES To study the inhibitory effects and underlying mechanisms of XJ-8, a natural compound isolated from Sanguis draxonis, on platelet activation and thrombosis. METHODS The regulatory effects of XJ-8 on the dense granule release, thromboxane A2 synthesis, α-granule release, activation of integrin αIIbβ3, and aggregation of platelets induced by multiple agonists were investigated in in vitro experiments. The effects of XJ-8 on bleeding time and FeCl3 -induced carotid artery thrombosis were also evaluated in in vivo experiments. Furthermore, we investigated the underlying mechanisms by which XJ-8 exerted its pharmacological effects. RESULTS XJ-8 not only significantly inhibited the dense granule release, thromboxane A2 synthesis, and aggregation of platelets induced by multiple agonists, but also exerted extending effects on bleeding time and therapeutic effects on thrombotic disease. In addition, XJ-8 selectively and moderately inhibited the activity of mitogen-activated protein kinase kinase kinase 3 (MAP3K3) and the activation of signaling pathways downstream MAP3K3, which play important roles in platelet activation. CONCLUSION XJ-8 can inhibit platelet function and thrombosis by targeting MAP3K3, and has potential to be developed into a novel therapeutic agent for the treatment of thrombotic diseases.

Nowadays, the harm of antibiotics residues in environments to human health and ecological safety has been causing more and more attention. In this paper, a biochar based iron material (MBC) was used to activate persulfate (PS) for the removal of sulfadiazine (SDZ) from aqueous solution. Experiment results indicate that the degradation and mineralization of SDZ by MBC/PS system reached 91.79 and 60 % within 60 min under the optimal reaction conditions, respectively. MBC/PS system exhibited a better performance on SDZ removal compared with MBC/H2O2 system. The addition of Cu2+ ion could enhance the degradation of SDZ by MBC/PS system. PO43-, Cl- and SO42- had a certain degree of inhibitory effect on the SDZ degradation. Both radicals and non-radical species such as SO4•-, •OH and 1O2 participated in the degradation reaction of SDZ by MBC/PS system, but •OH was the main radical species responsible for SDZ degradation. The liquid chromatograph-mass spectrometer (LC-MS) technique was used to identify the intermediate products of SDZ, and it was proposed that the degradation of SDZ might be achieved through hydrolyzation, hydroxylation, deamination and amino-oxidization processes. A possible reaction mechanism involving a synergistic effect between PS homogeneous and heterogeneous activation processes as well as both radicals and non-radicals reactions was finally proposed.

Carbon monoxide (CO) has long been known as a "silent killer" because of its ability to bind hemoglobin (Hb), leading to reduced oxygen carrying capacity of Hb, which is the main cause of CO poisoning (COP) in humans. Emerging studies suggest that mitochondria is a key target of CO action that can impact key biological processes, including apoptosis, cellular proliferation, inflammation, and autophagy. Despite its toxicity at high concentrations, CO also exhibits cyto- and tissue-protective effects at low concentrations in animal models of organ injury and disease. Specifically, CO modulates the production of pro- or anti-inflammatory cytokines and mediators by regulating the NLRP3 inflammasome. Given that human diseases are strongly associated with inflammation, a deep understanding of the exact mechanism is helpful for treatment. Autophagic factors and inflammasomes interact in various situations, including inflammatory disease, and exosomes might function as the bridge between the inflammasome and autophagy activation. Thus, the interplay among autophagy, mitochondrial dysfunction, exosomes, and the inflammasome may play pivotal roles in the health effects of CO. In this review, we summarize the latest research on the beneficial and toxic effects of CO and their underlying mechanisms, focusing on the important role of the inflammasome and its possible crosstalk with autophagy and exosomes. This knowledge may lead to the development of new therapies for inflammation-related diseases and is essential for the development of new therapeutic strategies and biomarkers of COP.

Ribosome recycling is the final step of the cyclic process of translation, where the post-termination complex (PoTC) is disassembled by the concerted action of ribosome recycling factor (RRF) and elongation factor G (EF-G) in the sub-second time range. Since, however, both the RRF and PoTC display highly dynamic action during this process, it is difficult to assess the molecular details of the interactions between the factors and the ribosome that are essential for rapid subunit separation. Here we characterized the molecular dynamics of RRF and PoTC by combined use of molecular dynamics simulations, single molecule fluorescence detection and single-particle cryo-EM analysis, with time resolutions in the sub-millisecond to minute range. We found that RRF displays two-layer dynamics: intra- and inter-molecular dynamics during ribosome splitting. The intra-molecular dynamics exhibits two different configurations of RRF: 'bent' and 'extended'. A single-site mutant of RRF increases its propensity to the 'extended' conformation and leads to a higher binding affinity of RRF to the PoTC. The inter-molecular dynamics between RRF and EF-G in the PoTC reveals that the domain IV of EF-G pushes against the domain II of RRF, triggering the disruption of the major inter-subunit bridge B2a, and catalyzes the splitting.

Lead zirconate titanate (PZT) films have been deposited on Ti–Pt/Ti/SiO2/Si(100) alloy substrates by sol-gel process. The purpose of the present study was to examine the Ti content in the Ti–Pt alloy layers-dependent preferred orientation and electrical behaviors of PZT films. X-ray diffraction (XRD) shows that Ti–Pt alloy electrodes induces texture transition from (100) to (111), and the maximum peak of (100) and minimum peak of (111) are obtained in the sample on Ti–Pt alloy layer with a sputtering power of 12.5 W/150 W. The film deposited on Ti–Pt alloy layer with a sputtering power of 12.5 W/150 W exhibits a reduced oxygen vacancies concentration, which results in a maximum e of 1224.25, an enhanced 2Pr of 40.5 μC/cm2, and a relative decreased 2Ec of 108 kV/cm. Therefore, it can be concluded that the Ti–Pt alloy layers with an appropriate Ti content play a very critical role for the preferred orientation, microstructure, and improved electrical properties of the PZT films.

Recently, more and more attention has been paid to the strong oxidation ability of newly prepared potassium ferrate (NAPF) in sludge reduction process, but less attention has been paid to the change of phosphorus in this process. The feasibility of phosphorus migration and transformation during excess sludge reduction pretreatment using NAPF pre-oxidation combined with anaerobic digestion was investigated. After 70 mg/g suspended solids NAPF pretreatment and 16 days anaerobic digestion, the solid-phase volatile suspended solids decreased by 44.2%, and much organic matter had been released into the liquid-phase and then degraded during digestion by indigenous microorganisms. As the sludge pre-oxidation process was performed, solid-phase organic phosphorus and chemically combined phosphorus also released into the liquid-phase as PO43−, peaking at 100 mg/L. During anaerobic digestion, the Fe3+ in the liquid-phase was gradually reduced to Fe2+, and then formed Fe2+-PO43− compound crystals and re-migrated to the solid-phase. The concentration of PO43− decreased to 17.08±1.1 mg/L in the liquid-phase after anaerobic digestion. Finally, the phosphorus in the Fe2+-PO43− compound accounts for 80% of the total phosphorus in the solid-phase. A large number of vivianite crystals in sludge were observed. Therefore, this technology not only effectively reduces sludge, but also increases the proportion of PO43− in the sludge in the form of Vivianite.

Transdermal drug delivery is favored in clinical therapy because of its ability to overcome the shortcomings of the first pass elimination of the liver caused by traditional oral administration and the irreversibility of the injection. However, skin stratum corneum (SC) forms a big barrier that precludes most of the biomacromolecules. Herein, we propose the engineering of transformed Escherichia coli (E. coli) derived outer membrane vesicles, detoxified by lysozymes (named TEVs) as the carrier for transdermal drug delivery. TEVs were derived from transgenic E. coli and then modified by an integrin alpha(v)beta(3) (αvβ3) targeting peptide and co-loaded with indocyanine green (ICG) (P-TEVs-G). TEVs were shown to have excellence in penetrating through intact SC without any additional enhancement, followed by targeting of melanoma cells. TEVs are promising nanoplatforms for transdermal and tumor targeting drug delivery with high efficacy and biosafety, possessing great potential in the treatment of superficial tumors.

Serum sulfatides are critical glycosphingolipids that are present in lipoproteins and exert anticoagulant effects. A previous study reported decreased levels of serum sulfatides in hemodialysis patients and suggested an association with cardiovascular disease. However, the mechanism of changes in serum sulfatides in chronic kidney dysfunction has not been well investigated. The current study examined whether a chronic kidney disease (CKD) state could decrease serum sulfatide levels using 5/6 nephrectomy (5/6NCKD) mice, an established CKD murine model, and studied the mechanisms contributing to diminished sulfatides. 5/6NCKD mice and sham operation control mice were sacrificed at the 4th or 12th postoperative week (POW) for measurement of serum sulfatide levels. Hepatic sulfatide content, which is the origin of serum sulfatides, and the expression of sulfatide metabolic enzymes in liver tissue were assessed as well. The 5/6NCKD mice developed CKD and showed increased serum creatinine and indoxyl sulfate. The serum levels and hepatic amounts of sulfatides were significantly decreased in 5/6NCKD mice at both 4 and 12 POW, while the degradative enzymes of sulfatides arylsulfatase A and galactosylceramidase were significantly increased. In a Hepa1-6 murine liver cell line, indoxyl sulfate addition caused intracellular levels of sulfatides to decrease and degradative enzymes of sulfatides to increase in a manner comparable to the changes in 5/6NCKD mice liver tissue. In conclusion, chronic kidney dysfunction causes degradation of sulfatides in the liver to decrease serum sulfatide levels. One explanation of these results is that indoxyl sulfate, a uremic toxin, accelerates the degradation of sulfatides in liver tissue.

The pollution of heavy metals and organic compounds has received increased attention in recent years. In the current study, a novel biochar-based iron oxide composite (FeYBC) was successfully synthesized using pomelo peel and ferric chloride solution through one-step process at moderate temperature. Results clearly demonstrate that FeYBC exhibited more efficient removal of Cr(VI) and/or phenol compared with the pristine biochar, and the maximum adsorption amounts of Cr(VI) and phenol by FeYBC could reach 24.37 and 39.32 mg g−1, respectively. A series of characterization data suggests that several iron oxides such as Fe2O3, Fe0, FeOOH and Fe3O4 were formed on the FeYBC surface as well as oxygen-containing groups. Thermodynamics study indicates that Cr(VI) and phenol adsorption by FeYBC were endothermic and exothermic processes, respectively. Langmuir adsorption isotherm and pseudo-second order models could better explain the Cr(VI) and phenol adsorption behaviors over FeYBC. The Cr(VI) adsorption might be primarily achieved through the ion exchange and surface complexation and reduction, whereas the π–π interaction and electron donor–acceptor complex mainly contributed to phenol adsorption. The findings indicate that the biochar-based iron oxide composites material was an efficient adsorbent for the remediation of industrial effluents containing Cr(VI) and phenol.

Paeoniflorin, a natural product derived from Paeonia lactiflora, possesses diverse pharmacological activities such as anti-inflammatory, antitumor, and antidiabetic effects. It has been reported for promoting osteoblastogenesis and inhibiting osteoclastogenesis. This study investigates the therapeutic effects of paeoniflorin in glucocorticoid-induced osteoporosis (GIOP) in vitro and in vivo. MC3T3-E1 cells were incubated with dexamethasone (DEX; 200 μM) and/or paeoniflorin (10 μM), followed by the investigation of cell proliferation, differentiation, mineralization, apoptosis, and autophagy. The AKT activator SC79 was used for evaluating the involvement of the AKT/mTOR signaling pathway. After DEX pretreatments, paeoniflorin promoted osteoblast differentiation and mineralization characterized by increase in Runx2, ALP, beclin-1, and LC3-II/LC3-I ratio levels and a decrease in apoptosis. The autophagy-promoting effects of paeoniflorin were reversed by SC79. C57BL/6 mice were given DEX (1 mg/kg) once daily and paeoniflorin (15 mg/kg) 48 hours for a total of 8 weeks followed by the investigation of histological changes, the trabecular bone microarchitecture, and the levels of bone turnover markers. The results showed that paeoniflorin increased alkaline phosphatase (ALP) activity and upregulated the expression of osteocalcin and beclin-1 but reduced the levels of Bax and C-terminal telopeptide of type I collagen (CTX-1). Thus, paeoniflorin may alleviate DEX-induced osteoporosis by promoting osteogenic differentiation and autophagy via inhibition of the AKT/mTOR signaling pathway.

Luminescent materials with dynamic responsiveness to external stimuli have attracted extensive attention for the development of advanced sensors and smart materials; however, self-healing capability is also of great importance for functional soft materials. An acid/base vapor reversibly triggered luminescence switch with self-healing ability is achieved by incorporating dynamic lanthanide metal-ligand (Ln-L) coordination into the soft polydimethylsiloxane polymer network. The emission color of the resultant luminescent material could be modulated by altering either the Eu3+/Tb3+ molar ratio or the excitation wavelength. The luminescence "On-Off" reversible switch is realized via direct alternating exposure to acid and base vapor, realizing reversible information encryption and decryption. The dynamic Ln-L cross-link as well as the hydrogen bond in the luminescent material endow it with excellent self-healing capability, high toughness, and stretchability. We believe this acid/base vapor-triggered self-healing switching strategy provides new insights for expanding the application range of luminescent materials.

Chinese quince fruits (Chaenomeles sinensis) have an abundance of lignins with antioxidant activities. To facilitate the utilization of Chinese quince fruits, lignin was isolated from it by auto-catalyzed ethanol organosolv pretreatment. The effects of three processing conditions (temperature, time, and ethanol concentration) on yield, structural features and antioxidant activities of the auto-catalyzed ethanol organosolv lignin samples were assessed individually. Results showed the pretreatment temperature was the most significant factor; it affected the molecular weight, S/G ratio, number of β-O-4' linkages, thermal stability, and antioxidant activities of lignin samples. According to the GPC analyses, the molecular weight of lignin samples had a negative correlation with pretreatment temperature. 2D-HSQC NMR and Py-GC/MS results revealed that the S/G ratios of lignin samples increased with temperature, while total phenolic hydroxyl content of lignin samples decreased. The structural characterization clearly indicated that the various pretreatment conditions affected the structures of organosolv lignin, which further resulted in differences in the antioxidant activities of the lignin samples. These results can be helpful for controlling and optimizing delignification during auto-catalyzed ethanol organosolv pretreatment, and they provide theoretical support for the potential applications of Chinese quince fruits lignin as a natural antioxidant in the food industry.

Maintaining a balance between economic development and carbon emissions reduction is an important part of low-carbon development in modern cities. At present, the positive effect of urban compactness on carbon emission efficiency has been demonstrated in large cities, but few studies have been carried out on small towns. Small towns are an important part of China’s urban system, accounting for 70% of the total population and 60% of the national GDP. Most small towns in China still promote economic growth and enhance the social welfare of residents by large-scale urban construction, which inevitably leads to urban expansion and high carbon emissions. How to reduce carbon emissions by optimising urban form while continuing with economic development and maintaining people’s welfare has become an important issue faced by small towns in China. To guide the low-carbon planning of small towns, it is necessary to understand the relationship between urban compactness and the economic benefit and socialwelfare levels associated with the carbon emissions in small towns. This study quantitatively analyse the relationship between urban compactness and carbon emission efficiency (including CO2 economic efficiency and CO2 social efficiency) in small towns in the Yangtze River Delta (YRD) from 2008 to 2017. This study resulted in four main findings. (i) the expansion of urban scale had significantly improved the CO2 economic efficiency and CO2 social efficiency; (ii) the compactness presented opposite effects on the CO2 economic efficiency and CO2 social efficiency, compactness had a negative correlation with CO2 economic efficiency, and had a positive correlation with CO2 social efficiency; (ii) The CO2 economic efficiency and CO2 social efficiency both show an upward trend over the period 2008 to 2017; (iv) The relationship between GDP and carbon emissions in small towns did not reach an ideal state, the economies of small towns in China are still strongly dependent on scale expansion.

Nowadays, environmental problems caused by residual antibiotics are getting increasing attention. In the present work, peroxymonosulfate (PMS) was firstly employed for the enhanced degradation of norfloxacin (NOF) by a calcium-based Ag3PO4 composite (Ca-Ag3PO4) under visible light irradiation. Experiment results show that NOF removal in Ca-Ag3PO4/PMS/visible light process was higher than the sum of that in Ca-Ag3PO4/visible light and Ca-Ag3PO4/PMS processes. This significant enhancement of NOF removal was mainly due to a synergistic effect between photocatalysis of Ca-Ag3PO4/visible light process and Fenton reaction of Ca-Ag3PO4/PMS process. The inhibitory effects of water quality components on NOF removal followed: Humic acid (HA) > PO43-> HCO3−> NO3−> Cl−. NOF and co-existing heavy metals (ie., Cr(VI) and Ni(II)) or organic compounds like tetracycline (TC) could be simultaneously removed. Both PMS and H2O2 exhibit positive effects on the removal of NOF, but PMS could more effectively improve NOF removal compared with H2O2. An excellent PMS decomposition had been achieved in Ca-Ag3PO4/PMS/visible light process. HO•, SO4•− and 1O2 all took part in NOF degradation by Ca-Ag3PO4/PMS/visible light process, but both HO• and SO4•− might be primary species for NOF degradation. A plausible degradation pathway of NOF in Ca-Ag3PO4/PMS/visible light process was thereby proposed to proceed through ring-opening cracking hydroxylation and elimination reactions reactions. The enhanced reaction mechanism for the degradation of NOF in Ca-Ag3PO4/PMS/visible light process was also proposed.

A zinc-mediated Mannich-type transformation of 2,2,2-trifluorodiazoethane with a series of imines has been described. This method provides facile access to a wide range of trifluorodiazoethyl-substituted amines in moderate to high yields under mild conditions. The synthetic utility of the afforded adducts is demonstrated by further transformations to valuable β-CF3-amines.

In this study, FeS2@SiO2 microspheres were firstly employed as a heterogeneous catalyst to activate persulfate (PS) for the degradation of bisphenol A (BPA) from aqueous solutions. The most relevant findings revealed that UV irradiation induced a significant improvement in the degradation of BPA by the FeS2@SiO2 microspheres/PS system. Nearly 100% of BPA degradation by the FeS2@SiO2 microspheres/PS/UV system was achieved within 120 min at reaction conditions of 1 mM PS, 0.066 mM BPA, 1.0 g/L FeS2@SiO2 microspheres and pH 3.0. A high performance on the degradation of BPA might be attributable to a synergistic effect between the PS/UV and the FeS2@SiO2 microspheres/PS catalytic processes. It was found that the BPA degradation could be inhibited by the coexisting anions like Cl−, HCO3− and PO43− to different extents at much higher concentrations, whereas NO3− had a negligible effect. Organic acids such as ethylene diamine tetra-acetic acid (EDTA) and oxalic acid (OA) would lead to an enhancement with a lower dosage, whereas a significantly negative effect was observed at much higher dosages. Radical scavenging tests revealed that the SO4 − radicals prevailed over HO . A total of seven intermediates during the degradation of BPA were identified by GC/MS, and a possible reaction pathway and mechanism of BPA degradation by the FeS2@SiO2 microspheres/PS/UV system was proposed. This study demonstrated a simple water treatment method involving the use of low cost natural iron minerals for organic pollutants removal.

Leonurine hydrochloride (LH) is a synthetic chemical compound derived from leonurine that can be extracted from Leonurus sibiricus and possesses antioxidant, anti-apoptosis, and neuroprotective activities. In previous studies, LH has been demonstrated to attenuate osteoclast activity and prevent bone loss. However, it is unknown whether LH accelerates bone formation and promotes osteogenic differentiation. We systematically examined the effects of LH on ovariectomized-induced osteoporotic mice and the MC3T3-E1 osteoblastic cell line. The results revealed that LH enhanced differentiation of MC3T3-E1 cells, with a dose-dependent increase in alkaline phosphatase (ALP) activity. Moreover, LH upregulated osteogenesis-related gene expression, including osterix, alpha 1 type 1 collagen, runt-related transcription factor 2 (Runx2) and ALP, as shown by quantitative reverse transcription-polymerase chain reaction analysis. At the same time, elevated expression of low-density lipoprotein receptor-related protein 5 and β-catenin mRNA was detected in the Wnt/β-catenin pathway. A western blot analysis revealed that LH dose-dependently increased the expression of Runx2 and β-catenin, and promoted phosphorylation of glycogen synthase kinase-3β in vitro. The in vivo results showed that administering LH (15 mg/kg/d) for 8 weeks alleviated destruction of the trabecular microstructure caused by osteoporosis. LH increased the bone mineral density and trabecular number, decreased trabecular separation according to a micro-computed tomography scan. In addition, LH enhanced the expression of β-catenin and Runx2 in vivo. In conclusion, LH promoted osteogenic differentiation and bone formation in vivo and in vitro, which alleviated osteoporosis through activation of the Wnt/β-catenin pathway.

An approach to construct a secondary asynchronous spectrum via sample-sample correlation (SASS) is proposed to analyze bilinear data from hyphenated spectroscopic experiments. In SASS, bilinear data is used to construct a series of two-dimensional (2D) sample-sample correlation spectra. Then a vertical slice is extracted from each 2D sample-sample correlation spectrum so that a secondary 2D asynchronous spectrum is constructed via these slices. The advantage of SASS is demonstrated by a model system with the following challenging situations: (1) Temporal profiles of different components severely overlap, making spectra of pure components difficult to directly obtain from either original bilinear data or multivariate curve resolution-alternating least squares (MCR-ALS) with non-negativity and unimodality constraints. (2) Every peak in the spectra of the eluted samples contains contributions from at least two components. Hence, two-dimensional correlation spectroscopy (2D-COS) and n-dimensional (nD) asynchronous spectroscopic method developed in our previous work, which previously worked so well, are now invalid. SASS managed to reveal different groups of systematic absences of cross peaks (SACPs) that reflect the lack of spectral contributions of different components at different regions in the second asynchronous spectrum. Spectra of different components can still be faithfully retrieved via MCR-ALS calculation using constraints revealed by different groups of SACPs. The results demonstrate that implicit but intrinsic information revealed by SASS is indispensable in solving challenging bilinear data as the model system. We applied SASS on two real-world examples from thermogravimetry-Fourier transform infrared spectroscopy (TG-FT-IR) experiments of mixtures (H2O/HOD/D2O and H2O/isopropanol/pyridine). FT-IR spectra of different components were successfully recovered. Moreover, FT-IR spectrum of HOD, which is difficult to obtain, was successfully extracted. SASS can be applied in the analysis of gaseous mixtures from TG-FT-IR experiment and a combination of quantum cascade lasers with substrate-integrated hollow waveguides in environmental monitoring and biomedical diagnosis. Furthermore, SASS is also useful in various advanced hyphenated spectroscopic experiments.

HPLC-FTIR analysis using a novel apparatus with CuO powder as an interface is reported. This apparatus initially serves as a reservoir for the dilute eluted solution of HPLC, and then acts as an enrichment device by combining diffusion and evaporation processes. It can be used not only to effectively remove the mobile phase of the eluted solution, but also to enrich the analyte within a tiny spatially resolved separated sample spot whose size is suitable for obtaining spectra using an FTIR microscope. An experimental demonstration using benzamide and sodium dodecyl benzene sulfonate shows that this apparatus is readily applicable in the analysis of real-world mixture samples.

Dissolved phosphorus (P), an important bioavailable nutrient element, is one of the key indicators of eutrophication levels, and has been routinely measured for decades in aquatic environments. The current EPA recommended colorimetric method has been criticized for its time-consuming step of sample preparation and generation of toxic waste through the use of heavy metal catalysts. In this study, a fast, accurate, and interference-free method for the determination of dissolved P in environmental waters based on inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was developed. This ICP-MS/MS was operated in the MS/MS mode to provide an interference-free measurement. The developed method exhibited excellent linearity (R2 = 0.9999) over a concentration range of 0.5–500 μg L−1, with a limit of detection of 8.1 ng L−1 in 5% nitric acid solutions. The recoveries (90%–105% in water samples) and the concentrations determined by this method were in good agreement with those determined using the recommended colorimetric method. Comparing with the colorimetric method, the proposed method for determination of dissolved P exhibited great advantages such as shorter experiment time, lower limit of detection and higher sample throughput.

3A2g → 3T1g(P) transition band of Ni2 + is used to probe the coordination of Ni2 +. Two-dimensional asynchronous spectra (2DCOS) are generated using the D ouble A synchronous O rthogonal S ample D esign (DAOSD), A synchronous S pectrum with A uxiliary P eaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g → 3T1g(P) transition band of Ni2 + are utilized to probe coordination between Ni2 + and various ligands. We studied the spectral behavior of the 3A2g → 3T1g(P) transition band when Ni2 + is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2 + and galactitol is also investigated. Although no clearly observable change is found on the 3A2g → 3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2 + and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g → 3T1g(P) transition band of Ni(galactitol)x2 + is considerably different from those of Ni(H2O)62 +. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.

Silicon nitride (Si3N4) products with different nanostructure morphologies and different phases for Si3N4 ceramic with high thermal conductivity were synthesized by a direct nitriding method. NaCl and NH4Cl were added to raw Si powders, and the reaction was carried out under a nitrogen gas flow of 100 mL/min. The phase composition and morphologies of the products were systemically characterized by X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. At 1450 °C, the NaCl content was 30 wt %, the NH4Cl content was 3 wt %, and the maximum α-Si3N4 content was 96 wt %. The process of Si nitridation can be divided into three stages by analyzing the reaction schemes: in the first stage (25–900 °C), NH4Cl decomposition and the generation of stacked amorphous Si3N4 occurs; in the second stage (900–1450 °C), NaCl melts and Si3N4 generates; and in the third stage (>1450 °C), α-Si3N4 → β-Si3N4 phase change and the evaporation of NaCl occurs. The product...

Magnesium silicon nitride (MgSiN2) was synthesized without any additives under a nitrogen gas flow (200 mL/min) using a nitriding method. The effects of temperature and holding time on its purity and morphology were investigated. A single-phase MgSiN2 powder was obtained at 1350℃ for 1 h and 1250℃ for 11 h. However, the decomposition of MgSiN2 occurred at 1450℃, suggesting that the optimum temperature for the preparation of MgSiN2 from Mg-Si system was 1350℃. The phase purity, morphology, size of the product and elemental composition of the samples were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy spectrometer (EDS), respectively. The evaporation of Mg and Si resulted in the formation of many voids in the blocky product. The temperature gradient promotes the growth of MgSiN2 on the surface of massive products along the tip. The concentration gradient of Mg and Si vapors in the void resulted in the columnar growth of MgSiN2.

In recent years, a serious threat of antibiotic residues in aquatic environments to human health and ecological security has become increasingly widespread attention. In this study, this is the first report on an alternative strategy on enhanced degradation of amoxicillin (AMX) and norfloxacin (NOF) by TiO2@nZVI/persulfate (PS) process under UV irradiation. Results revealed that a signficantly synergistic effect on AMX degradation had been achieved in TiO2@nZVI/PS/UV process due to the photocatalysis and Fenton-like reactions. NO3–, HCO3–, PO43- and humic acid exhibited inhibitory effects on AMX degradation, whereas Cl- was negligible on that. The degradation of AMX decreased as the addition of Cr(VI) concentrations increased, whereas the correspond values were enhanced when a low Cu(II) concentration was introduced. TiO2@nZVI/PS/UV process was the most efficient for activating PS decomposition. HO•, SO4•− and 1O2 were all generated in TiO2@nZVI/PS/UV process, but HO• and SO4•− were the dominant radical species for AMX degradation. The AMX intermediates products identified by LC-MS system confirmed AMX was effectively degraded through hydroxylation and deamination reactions. A better performance on the simultaneous removals of AMX and NOF by TiO2@nZVI/PS/UV process could be achieved at lower concentration conditions, and the simultaneous reaction mechanism was thereby proposed base on expriment results.

Silicon nitride (Si3N4) was synthesized under a nitrogen gas flow (100 mL/min) using a molten salt nitriding method to investigate the effects of the temperature and NaCl content on the α-Si3N4 content in products and their micro-morphologies. Adding NaCl and β-Si3N4 in silicon powders resulted in Si nitridation products divided into two layers. Analysis of the lower product using X-ray diffraction revealed a change in the α-Si3N4 content with changes in the temperature and NaCl content. Analysis of the lower and upper layers using scanning electron microscopy revealed that the upper layer contained Si3N4 nanowires, Si3N4 nanobelts, and clastic oxide impurities; the lower one contained short needle-like and blocky Si3N4. From the microstructures of the products, the product morphology related to that the dry mixing procedure did not correspond to homogenization of the starting Si-Si3N4-NaCl mixtures and the different concentrations of raw materials resulted in different morphologies.

Some of the effects of dioxins seem to be different between men and women, and exposures starting at an early age seem to have more prominent effects. Therefore, we conducted a study in Taiwan to evaluate the associations between exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and metabolic syndrome (MetS) starting at different ages in both sexes.We recruited participants from an area where residents were exposed to PCDD/Fs released from a factory and defined serum PCDD/Fs levels ≥20 pg WHO98-TEQDF/g lipid as high dioxin levels. MetS was defined as meeting three of the following criteria: fasting glucose ≥100 mg/dl or under treatment for diabetes, waist circumference ≥90 cm in men or ≥80 cm in women, triglycerides ≥150 mg/dl or under treatment for elevated triglycerides, high-density lipoprotein40 mg/dl in men or50 mg/dl in women, and blood pressures ≥130/85 mmHg or under treatment for hypertension.Of the 2758 participants, 785 patients with MetS were identified, and we observed positive associations between a high dioxin level and MetS. After adjusting for sex, age, and age at starting exposure, we found that a high dioxin level was an independent predictor for MetS (adjusted odds ratio =1.38; 95% confidence interval = 1.11, 1.72). When we stratified the participants by gender, we found that a high dioxin level remained an independent predictor of MetS in men, but not in women, regardless of the age at starting exposure.Exposure to PCDD/Fs was associated with MetS in men, independent of age and age at starting exposure.

In this work, we investigated the influence of polyvinylpyrrolidone (PVP) on the solubility of artemisinin in aqueous solution by using quantitative 1H NMR. Experimental results demonstrate that about 4 times of incremental increase occurs on the solubility of artemisinin upon introducing PVP. In addition, dipole-dipole interaction between the ester group of artemisinin and the amide group of N-methylpyrrolidone (NMP), a model compound of PVP, is characterized by two-dimensional (2D) correlation FTIR spectroscopy with the DAOSD (Double Asynchronous Orthogonal Sample Design) approach developed in our previous work. The observation of cross peaks in a pair of 2D asynchronous spectra suggests that dipole-dipole interaction indeed occurs between the ester group of artemisinin and amide group of NMP. Moreover, the pattern of cross peaks indicates that the carbonyl band of artemisinin undergoes blue-shift while the bandwidth and absorptivity increases via interaction with NMP, and the amide band of NMP undergoes blue-shift while the absorptivity increases via interaction with artemisinin. Dipole-dipole interaction, as one of the strongest intermolecular interaction between artemisinin and excipient, may play an important role in the enhancement of the solubility of artemisinin in aqueous solution.

In this study, the feasibility of using copper oxide (CuO) as an interface for the coupling of liquid chromatography (LC) and Fourier-transform infrared (FTIR) spectroscopy was investigated. CuO exhibits low absorption in the 4000 to 1000 cm-1 FTIR spectral region. In addition, LC-FTIR using CuO as the interface was extended to the analysis of sample mixtures containing benzamide and dioctyl sebacate; both analytes were successfully separated. After complete removal of the mobile phase, benzamide and dioctyl sebacate were successfully identified from the FTIR spectrum. Surprisingly, the interference from adsorbed water or conventionally used LC solvents in the FTIR spectrum was completely eliminated by using CuO particles as the interface in the off-line hyphenation of LC-FTIR. Based on these results, CuO demonstrates potential as an ideal interface for LC-FTIR analysis.

Consumption of trans-fatty acids (TFA), unsaturated fatty acids (FA) containing trans double bonds, is a risk factor for metabolic syndrome and steatohepatitis. Peroxisome proliferator-activated receptor α (PPARα) is a master regulator of hepatic lipid homeostasis. To examine the contribution of PPARα to changes in liver phenotypes induced by TFA, two diets were used: a purified control diet and an isocaloric diet in which most of the soybean oil, a major source of FA in the diet, was replaced with TFA-rich shortening. The diets were fed to wild-type and Ppara-null mice for 2 months. Ppara-null mice fed a TFA-containing diet showed more severe hepatic steatosis and liver damage compared with similarly treated wild-type mice, as revealed by increased hepatic triglyceride (TG) contents and serum alanine aminotransferase activities. While the TFA-rich diet increased the hepatic expression of enzymes involved in de novo FA synthesis and decreased TG-hydrolyzing enzymes in both genotypes, the expression of FA-catabolizing enzymes was decreased in Ppara-null mice, resulting in more severe hepatosteatosis. Additionally, the expression levels of key contributors to inflammation, such as osteopontin, were increased, and nuclear factor-kappa B was activated in TFA-containing diet-fed Ppara-null mice. Enhanced inflammatory signaling in these mice was presumably mediated by toll-like receptor 2, with no accompanying inflammasome activation. Collectively, these results suggest a protective role for PPARα in the pathological changes in the liver following TFA consumption. PPARα might prevent TFA-containing diet-induced steatohepatitis.

Four metal complexes based on quinoline carboxylate ligand from 2-(pyridin-4-yl)quinoline-4-carboxylic acid ( HL ), { [ML 2 (H 2 O) 2 ]∙2H 2 O} n (M = Mn II , 1 ; M = Co II , 2 ; M= Cd II , 3 ) and { [Ag 2 L 2 (H 2 O) 2 ]∙3H 2 O} n ( 4 ) have been synthesized under hydrothermal conditions. Their structures were determined by elemental analyses, IR spectra, and further characterized by single-crystal X-ray diffraction analysis. Complexes 1 – 3 feature a 1D chain structure which is further linked together to construct the 3D supramolecular network through hydrogen bonds. Complex 4 exhibits a 3D configuration. The fluorescent behavior and antibacterial activities of these compounds have been investigated.

The study characterized the enrichment, ecological risk and possible source of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in sediments from a typical mariculture bay. The concentrations of the metals were analyzed in sediments collected from Zhelin bay. The distribution variation was examined during the past decade, which had an increase tendency till 2011. The enrichment factor and geoaccumulation indices suggested Pb, As, Cu and Zn were minor enrichment and unpolluted to moderately polluted, and Ni at cage mariculture area was moderately-severe enrichment and strongly polluted. This area had medium to high ecological risk, especially at the northwest coastal area of semi-closed bay, with high-medium to high ecological risk. Correlation and principal component analyses indicated that most of heavy metals, especially for As, Pb and Ni, primarily resulted from the combustion of gasoline and diesel fuel and the ship protective layer.

Human activities have distinctly enhanced the deposition levels of atmospheric nitrogen (N) pollutants into terrestrial ecosystems, but whether and to what extents soil carbon (C) and N status have been influenced by elevated N inputs remain poorly understood in the ‘real’ world given related knowledge has largely based on N-addition experiments. Here we reported soil organic C (OC) and total N (TN) for twenty-seven forests along a gradient of N deposition (22.4–112.9 kg N/ha/yr) in the Beijing-Tianjin-Hebei (BTH) region of northern China, a global hotspot of high N pollution. Levels of soil TN in forests of the BTH region have been elevated compared with investigations in past decades, suggesting that long-term N deposition might cause soil TN increases. Combining with major geographical and environmental factors among the study forests, we found unexpectedly that soil moisture and pH values rather than N deposition levels were major regulators of the observed spatial variations of soil OC and TN contents. As soil moisture and pH values increased with mean annual precipitation and temperature, respectively, soil C and N status in forests of the BTH region might be more responsive to climate change than to N pollution. These evidence suggests that both N deposition and climate differences should be considered into managing ecosystem functions of forest resources in regions with high N pollution.

A novel approach to use two-dimensional correlation spectroscopy (2D-COS) to analyze bilinear data is proposed. A phenomenon called Systematic Absence of Cross Peaks (SACPs) is observed in a 2D asynchronous spectrum. Two theorems relevant to SACPs have been derived. The SACP-based 2D-COS method has been successfully applied on analyzing bilinear data from mixed samples (including one model system and two real systems). Implicit isolated peaks can be identified and assigned to different components based on characteristic pattern of SACPs even if the time-related profiles of different components are severely overlapped. Based on the results of SACPs, spectra of pure components can be retrieved. Identification of SACPs can still be achieved in the presence of artifacts. Thus, neither noise nor baseline drift can produce significant influence on the results obtained from the approach described in this paper. We have used several well-established chemometric methods, including N-Findr, VCA, and MCR with various initial settings, on two systems that can be successfully solved using the 2D-COS method. The chemometric methods mentioned above cannot provide correct spectra of pure components because of severe problem of rotational ambiguity derived from severe overlapping of the time-related profiles. Only when the information from SACPs in 2D-COS is used as additional constraints in MCR calculation, correct spectra can be obtained. That is to say, the SACP-based 2D-COS method provides intrinsic information which is crucial in the analysis of chromatographic-spectroscopic and analogous data even if the time-related profiles of different components overlap severely. © 2019 Elsevier B.V., This work was financially supported by National Natural Science Foundation of China (Nos. 21674065, 51373003 and 21705112) and Innovation of Instrumentation and Key Techniques Foundation of Peking University (Nos. 7101500246/001 and 7101500253/011).

BACKGROUND: To investigate the value of diffusion kurtosis imaging (DKI) and diffusion-weighted imaging (DWI) with a stretched exponential model (SEM) in the evaluation of tumor heterogeneity in an orthotopic hepatocellular carcinoma (HCC) xenograft model. METHODS: Thirty orthotopic HCC xenograft nude mice models were established and randomly divided into two groups, the sorafenib induction group (n=15) and control group (n=15). Every mouse in each group underwent MRI with DKI and SEM on a 1.5T MR scanner at 7, 14, and 21 days after sorafenib intervention. DKI and SEM parameters including mean kurtosis (MK), mean diffusivity (MD), α, and distributed diffusion coefficient (DDC) were measured, calculated, and compared between the two groups and among different time points. Sequential correlations between histopathological results including necrotic fraction (NF), micro-vessel density (MVD), Ki-67 index, standard deviation (SD), and kurtosis from hematoxylin-eosin staining, and DKI and SEM parameters were analyzed. RESULTS: MK, MD, and DDC of HCC in the sorafenib induction group were significantly higher than those in the control group at each time point (P

Autologous vascular grafts have the advantages of better biocompatibility and prognosis. However, previous studies that implanted bare polymer tubes in animals to grow autologous tubular tissues were limited by their poor yield rates and stability. To enhance the yield rate of the tubular tissue, we employed a design with the addition of overlaid autologous whole blood scaffold containing lipopolysaccharides (LPS). Furthermore, we applied in vivo dynamic mechanical stimuli through cyclically inflatable silicone tube to improve the mechanical properties of the harvested tissues. The effectiveness of the modification was examined by implanting the tubes in the peritoneal cavity of rats. A group without mechanical stimuli served as the controls. After 24 days of culture including 16 days of cyclic mechanical stimuli, we harvested the tubular tissue forming on the silicone tube for analysis or further autologous interposition vascular grafting. In comparison with those without cyclic dynamic stimuli, tubular tissues with this treatment during in vivo culture had stronger mechanical properties, better smooth muscle differentiation, and more collagen and elastin expression by the end of incubation period in the peritoneal cavity. The grafts remained patent after 4 months of implantation and showed the presence of endothelial and smooth muscle cells. This model shows a new prospect for vascular tissue engineering.

Background Carbon monoxide poisoning (COP) accounts for a large number of emergency department visits worldwide and is fatal in many cases. In surviving patients, neurological sequelae (NS) attributable to cerebral hypoxia are the most devastating outcome, but reliable predictors are limited. Therefore, we conducted a study to identify predictors of NS in patients with COP and evaluate their effects. Methods In this retrospective case-control study, we identified patients with COP in a medical center in Southern Taiwan between January 2005 and December 2014. Cases were patients with NS, and controls were patients without NS. We obtained information on potential predictors of NS from medical records and evaluated their association with NS, including demographic characteristics, exposure source, suicide attempts, duration of exposure (by tertile), histories, symptoms, signs, laboratory data, treatment, and the length of hospital stay. Results We included 371 patients with COP. Of them, 93 developed NS, and their mean ages (41.4 ± 14.7 years vs. 39.7 ± 14.2 years) and proportions of males (59.1% vs. 58.6%) were similar to those in the 298 controls. Multivariate logistic regression showed that a history of hypertension (adjusted odds ratio = 2.1; 95% confidence interval = 1.0, 4.5) and a longer duration of carbon monoxide exposure (adjusted odds ratio = 1.7; 95% confidence interval = 1.1, 2.8; the longest tertile [>5 hours] vs. the other two tertiles [≤5 hours]) were independent predictors for NS, but not the level of carboxyhemoglobin. Conclusions This study identified two independent predictors for NS that may be useful for public healthcare workers and physicians in predicting outcomes and deciding on treatment strategies for COP patients.

Polyphenols have long been used as functional compounds and are beneficial for host immunity and gut health. This three-phased study investigated the function of Ouli fermented juice (OF) in improving the immunity of cyclophosphamide (CTX)-immunosuppressed mice and regulating their intestinal microbiota and mucosal barrier. Lactobacillus plantarum fermentation increased the phenolic content in the OF. OF effectively improved host immunity and the intestinal mucosal barrier, including increasing serum immunoglobulin (Ig)A, IgG, and IgM levels and secreted IgA (sIgA) levels in the colon, and reduced CTX-induced pathological damage to the spleen and jejunum. Importantly, OF effectively increased the abundance of Lachnospiracea, Roseburia, Akkermansia, and butyric acid-producing microbes, subsequently increasing the levels of short chain fatty acids in the colon. OF with polyphenols exhibited better efficacy at altering the intestinal flora, which might affect the host immunity by changing the host-mucosal barrier-microbiota interaction.

Nano-imprint technology is a method of nano-pattern reproduction, has the characteristics of high resolution, high throughput, and low-cost. It can reduce the complexity and cost of the equipment while improving the resolution, which considered a promising industrial production technology. The key to nanoimprinting lies in the mold, and the quality of the mold directly determines the quality of the imprinted graphics. Here, a method for fabricating sub-100 nm concave 2D silicon nano-mold by side etch lift-off is proposed. The effects of different wet etching time and the metal deposition angle on the width of nanochannels were studied. The measurement result of dry etching shows that on the entire 4 inch silicon wafer, the width of the nanochannel varies by 4% and the depth by 2%. The width of the nanochannel between chips varies by 0.7%, and the depth variation is 1%. With this new method, high-precision and large-scale silicon nano-mold can be produced, which has great potential for realizing high-precision and low-cost manufacturing of nano devices.

CD40 ligand (CD40L) and B-cell activating factor (BAFF) play important roles in the function of B cells. However, the difference of their regulatory effects remains obscure. In this study, we used anti-CD40 to imitate CD40L and investigated the different regulatory effects of CD40L and BAFF on the function of B cells. In the functional analyses, both anti-CD40 and BAFF significantly enhanced the survival and differentiation of B cells, and slightly increased the activation and proliferation. However, in the transcriptome analysis, anti-CD40 and BAFF exerted very different regulation on the gene expression profile of B cells. Anti-CD40 upregulated the expression of genes related to the adaptive immune function of B cells, but BAFF enhanced the genes associated with the innate immune function. Furthermore, the effect analysis of the combination of anti-CD40 or BAFF with anti-IgM also demonstrated that anti-CD40 could cooperate with anti-IgM to promote the proliferation of B cells, but BAFF could not do it. The mechanism study revealed that the different effects of anti-CD40 and BAFF on B cells were resulting from the different modulation on NF-кB, ERK1/2, and PI3K-AKT signaling pathways. Collectively, the results suggest that CD40L mainly promotes adaptive immune function of B cells, but BAFF primarily enhances innate immune function.

Nowadays, nanoscale zero valent iron (nZVI) has been extensively applied for the decontamination of various pollutants, but passivation of nZVI severely affects its reactivity in use. In this study, ultrasound (US)-assisted catalytic reduction of Cr(VI) by an acid mine drainage based nZVI (AMD-nZVI) coupling with FeS2 system was systematically examined. Results show that the presence of FeS2 and US induced a synergistic enhancement of Cr(VI) removal by AMD-nZVI. Nearly 98% of Cr(VI) removal was achieved by AMD-nZVI/FeS2/US process within 60 min under optimal reaction conditions. Several coexisting substances with lower concentration including Pb(II), Ni(II), bisphenol A (BPA) and 2,4-diclorophenol (2,4-DCP) could be effectively removed in simultaneous manner with Cr(VI) removal. The inhibitory order of water matrix species on Cr(VI) removal was NO3− > PO43− > HCO3− > Ca2+ > Mg2+ > Cl−, and a serious suppression effect was induced by humic acid (HA). Addition of ethylene diamine tetra-acetic acid (EDTA) and citric acid (CA) could enhance Cr(VI) removal rate. An enhanced reaction mechanism was proposed, which involved the regeneration of more Fe2+ and H+ by AMD-nZVI/FeS2/US process, leading to the reduction of Cr(VI) by AMD-nZVI and FeS2 into Cr(III) species inculding Cr2O3 and Cr(OH)3. This study well demonstrates that AMD-nZVI/FeS2/US process is considered as a potential candidate for the remediation of Cr(VI) in real wasterwater.

Anthropogenic nitrogen (N) emission has been the major cause of rapidly increasing atmospheric N deposition in many regions of the world. However, fluxes, distributions, and physi-chemical compositions of regional N deposition and the response of N deposition levels to N emissions remain poorly characterized, particularly in high N-emission regions. To explore these issues, this study collated observations on N deposition fluxes in the Beijing-Tianjin-Hebei (BTH) region of northern China. We found that total inorganic N (TIN) deposition in the study region averaged 61.3 ± 13 kg-N/ha/yr based on observations from 1998 to 2017. Respectively, about 97%, 73%, 20%, 32%, and 59% of farmland, constructed land, forest, grassland, and water areas had TIN deposition above 50 kg-N/ha/yr. These results indicated substantial ecological risks of atmospheric N loading to these ecosystems. Dry deposition accounted for 59% of TIN deposition and gaseous N accounted for 73% in dry IN deposition. In gaseous N deposition, ammonia, N dioxides, and nitric acid accounted for 42%, 47%, and 11%, respectively. Ratios of NH3-N (N in ammonia) to (NO2-N + HNO3-N) (N in N dioxides, nitric acid) or NH4-N (N in ammonium) to NO3-N (N in nitrate) averaged 0.8, 2.0, 1.0, 1.9, and 1.3 in gaseous, particulate, dry, wet, and total deposition fluxes, respectively. These indicated different transformation and deposition mechanisms between NH4-N and NO3-N under high emissions. Moreover, we found a non-linear relationship between TIN deposition and anthropogenic IN emissions. All these results provide a systematic assessment of the N deposition and its responses to human activities in a high N-emission region, which is valuable for emission mitigation and effect evaluation of regional N pollution.

Systematic Absence of Cross Peaks (SACPs) in a two-dimensional (2D) asynchronous spectrum, a sensitive indicator of the signal purity, is very important in analyzing bilinear data. However, identification of SACPs in practice remains a challenge because of noise in the corresponding 2D asynchronous spectrum. We firstly show that SACP can be identified via a statistical test using a large amount of 2D asynchronous spectra. To meet the practical demand that SACPs must be identified based on a single 2D asynchronous spectrum in many cases, we use a 2D quotient spectrum (Q (x, y)) as an effective auxiliary tool to recognize SACPs. The expectation of Q(x, y) is zero when (x, y) is within SACP or background regions in the corresponding 2D asynchronous spectrum. When (x, y) is in a cross-peak region, the expectation of the absolute value of Q(x, y) is a constant regardless of whether the cross-peak in a 2D asynchronous spectrum is strong or weak. Thus, a unified threshold can be set up to differentiate the SACP region from cross-peak region via the auxiliary 2D quotient spectrum. We have applied this approach on two real-world examples and satisfactory results have been obtained. This result demonstrates that the statistical test with a 2D quotient spectrum is applicable in real-world systems.

Intermolecular interaction between diethyl ether and dichloromethane was investigated by using double asynchronous orthogonal sample design (DAOSD) scheme. FT-IR spectra of the two compounds were measured in the gas phase. A gas cell that satisfied the requirement of the DAOSD approach was designed, fabricated and utilized. The appearance of cross peaks in a pair of asynchronous spectra demonstrated that intermolecular interaction occurred between two compounds. Interference from the spectra of solvent can be avoided by measuring the samples in gas phase, thereby extending the application range of DAOSD and relevant approaches.

Properties of 2D asynchronous spectra generated from a series of fluorescence emission spectra are investigated. Variable excitation wavelengths are utilized as an external perturbation. Based on the results of mathematical analysis and computer simulation, we find that no cross peak will be produced on the 2D asynchronous spectrum if the fluorescent solute under investigation occurs in a single micro-environment. The observation of cross peaks implies that the fluorescent molecule may occur in different micro-environments in a solution. Based on these results, we use 2D asynchronous spectra to investigate the emission spectra of anthracene dissolved in cyclohexane. When the concentration of anthracene is low, no cross peak is produced in the resultant 2D asynchronous spectrum, confirming that anthracene is dissolved as single molecule in the solution. As the concentration elevated, cross peaks appear in the corresponding 2D asynchronous spectra. A plausible explanation of this phenomenon is that anthracene may undergo aggregation via π-π interaction or π-C-H interaction.

We propose a substantially simplified approach to construct a pair of 2D asynchronous spectra based on the DAOSD approach proposed in our previous papers. By using a new concentration series, only three 1D spectra are used to generate a pair of 2D correlation spectra together with two reference spectra. By using this method, the previous problem of labor intensive traditional DAOSD approach has been successfully addressed. We apply the new approach to characterize intermolecular interaction between acetonitrile and butanone dissolved in carbon tetrachloride. The existence of intermolecular interaction between the two solutes can be confirmed by the presence of a cross peak in the resultant 2D IR spectra. In addition, the absence of cross peak around (2254, 2292) in Psi(butanone) provides another experimental evidence to reveal the intrinsic relationship between the stretching band and an overtone band (delta(CH3)+v(C-C)). (C) 2016 Elsevier B.V. All rights reserved.

The spectral behavior of a pair of 2D asynchronous spectra generated by using the double asynchronous orthogonal sample design (DAOSD) approach on a chemical system is investigated. Two solutes (P and Q) are dissolved in the solution and intermolecular interaction between P and Q is characterized. In this particular system, P occurs in two exchangeable states when it is dissolved in the solutions. Results on mathematical analysis and computer simulation demonstrated that interference unrelated to the intermolecular interaction can be completely removed. Hence the resultant 2D asynchronous spectra generated by using the DAOSD approach can reflect intermolecular interaction reliably. Moreover, properties of cross peaks in different regions of the pair of asynchronous spectra are discussed. In our previous works, cross peaks generated by using the DAOSD and relevant techniques reflect variations on peak position, bandwidth or absorptivity of the characteristic peaks of solutes caused by intermolecular interaction. However, we find that cross peak can still be produced even if intermolecular interaction do not bring about any changes on the characteristic peaks of solutes. Mathematical analysis demonstrates that cross peaks are related to the variations of chemical systems caused by intermolecular interaction at a network level.