[Microbial Mechanisms of Removal of Phthalic Acid Esters in Purple Soils Revealed Using Metagenomic Analysis].

The removal mechanisms of phthalic acid esters (PAEs) have attracted much attention because of their endocrine-disrupting properties and persistence in environmental media. In order to reveal the removal mechanism of PAEs and involved keystone taxa and functional genes, purple soils were polluted by di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP), respectively, along a gradient of 0, 5, 10, and 20 mg·kg-1 and cultured for 90 days in the dark. The results showed that the degradation dynamics of DBP and DEHP were well-fitted by the first-order kinetic model, and the half-life of DBP and DEHP ranged from 17.0 to 38.2 days. The degradation rate of DBP (5 mg·kg-1) was the fastest, and that of DEHP (20 mg·kg-1) was the slowest. The soil samples of the seventh day and the fifteenth day were analyzed using metagenomic sequencing. NMDS and cluster analysis showed that there was a significant difference between the bacterial community structure of soil samples from the seventh day and the fifteenth day. The relative abundance of Actinobacteria increased from the seventh day to the fifteenth day. The smaller the half-life of DBP or DEHP, the higher the relative abundance of Actinobacteria in the different treatments. In addition, Streptomyces was the dominant genus in all polluted soils. Co-occurrence network analysis elucidated that Pandoraea was a keystone genus of the soil bacterial communities, which could be used to indicate the pollution levels of DBP and DEHP. The results of KEGG annotation demonstrated that Pandoraea was responsible for benzoate degradation, quorum sensing, ABC transporters, and the two-component system and could promote the intercellular communications and the microbial growth and proliferation and maintain the stability of the community structure. Therefore, the degradation rate of DBP and DEHP in purple soils depended on their initial content and their own properties. Actinobacteria played an important role in the PAEs degradation, and Pandoraea played a major part in promoting PAEs degradation and regulating the stability of the structure and function of degrading bacterial communities.

Steady regime of radiation pressure acceleration with foil thickness adjustable within micrometers under a 10-100 PW laser.

Quasimonoenergetic GeV-scale protons are predicted to be efficiently generated via radiation pressure acceleration (RPA) when the foil thickness is matched with the laser intensity, e.g., L_{mat} of several nm to 100 nm for 10^{19}-10^{22}Wcm^{-2} available in laboratory. However, nonmonoenergetic protons with much lower energies than predicted were usually observed in RPA experiments because of too small foil thickness which cannot support insufficient laser contrast and foil surface roughness. Besides the technical problems, we here find that there is an upper-limit thickness L_{up} derived from the requirement that the laser energy should dominate over the ion source energy in the effective laser-proton interaction zone, and L_{up} is lower than L_{mat} with the intensity below 10^{22}Wcm^{-2}, which causes inefficient or unsteady RPA. As the intensity is enhanced to ≥10^{23}Wcm^{-2} provided by 10-100 PW laser facilities, L_{up} can significantly exceed L_{mat}, and therefore RPA becomes efficient. In this regime, L_{mat} acts as a lower-limit thickness for efficient RPA, so the matching thickness can be extended to a continuous range from L_{mat} to L_{up}; the range can reach micrometers, within which foil thickness is adjustable. This makes RPA steady and meanwhile the above technical problems can be overcome. Particle-in-cell simulation shows that multi-GeV quasimonoenergetic proton beams can be steadily generated and the fluctuation of the energy peaks and the energy conversation efficiency remains stable although the thickness is taken in a larger range with increasing intensity. This work predicts that near future RPA experiments with 10-100 PW facilities will enter a new regime with a large range of usable foil thicknesses that can be adjusted to the interaction conditions for steady acceleration.

Electromagnetically Induced Transparency in the Strongly Relativistic Regime.

Stable transport of laser beams in highly overdense plasmas is of significance in the fast ignition of inertial confinement fusion, relativistic electron generation, and powerful electromagnetic emission, but hard to realize. Early in 1996, Harris proposed an electromagnetically induced transparency (EIT) mechanism, analogous to the concept in atomic physics, to transport a low-frequency (LF) laser in overdense plasmas aided by a high-frequency pump laser. However, subsequent investigations show that EIT cannot occur in real plasmas with boundaries. Here, our particle-in-cell simulations show that EIT can occur in the strongly relativistic regime and result in stable propagation of a LF laser in bounded plasmas with tens of its critical density. A relativistic three-wave coupling model is developed, and the criteria and frequency passband for EIT occurrence are presented. The passband is sufficiently wide in the strongly relativistic regime, allowing EIT to work sustainably. Nevertheless, it is narrowed to nearly an isolated point in the weakly relativistic regime, which can explain the quenching of EIT in bounded plasmas found in previous investigations.

Magnetization of high-density plasma with a jet velocity of hundreds of km/s.

High magnetic fields at the kilotesla scale have been experimentally generated and finding methods to fully embed such fields into high-density plasma is interesting for magnetically assisted a fast ignition scheme of inertial confinement fusion, laboratory astrophysics, and magnetically guided fast electron beam for broad applications. We investigate diffusion and embedment of an external magnetic field inwards a high-density plasma by analysis and simulation. By introducing the magnetic Péclet number, dimensional analysis indicates that the magnetizing process is sensitive to the jet velocity, temperature, and size of the plasma and gives a phenomenological scaling law of the magnetic field embedment time with an arbitrary jet velocity. The analytical results are verified by magnetic field simulation and applied in 100-g/cm^{3}, 100-µm-radius plasmas with a jet velocity of 0-400 km/s and a temperature of 50-500 eV, typically adopted in experiments. Attributed to an effective electric field from frame transformation, the magnetic field embedment time can be significantly reduced by one order of magnitude when a jetting plasma is adopted with a velocity of hundreds of kilometers per second, e.g., from 5.5 ns in a static plasma to a 0.5 ns timescale in a jetting plasma of 200 km/s. The promoted embedment process favors for various applications mentioned above.

A non-collinear autocorrelator for single-shot characterization of ultrabroadband terahertz pulses.

Conventional terahertz (THz) waveform or spectral diagnostics mainly employ the electro-optic-based techniques or the multi-shot Michelson interferometer. Simultaneously, single-shot, ultrabroadband THz spectral measurements remain challenging. In this paper, a novel probe-free scheme based on the non-collinear autocorrelation technique is proposed to characterize the ultrabroadband THz spectrum at a single-shot mode. The non-collinear autocorrelator is a modified beam-division interferometer, in which the two beams are recombined non-collinearly onto a camera. The temporal or spectral resolution and range depend on the noncollinear configuration and camera parameters. This simple approach has been applied experimentally to characterize the ultrashort THz pulse generated from ultraintense laser-solid interactions, demonstrating the capability of single-shot ultrabroadband measurements without an auxiliary ultrafast laser probe. The proposed non-collinear autocorrelator here would be much useful for characterization and applications of low-repetition-rate intense THz sources and could also be extended to other frequency bands.

Six new sesquiterpenoids from the fruits of Xanthium italicum.

Four new germacrane-type sesquiterpenoids (1-4) and two new guaiane-type sesquiterpenoids (5-6) were isolated from the fruits of Xanthium italicum Moretti. The structures of the new compounds were elucidated on the basis of spectroscopic analysis and X-ray diffraction experiment. Compounds 1, 2 and 6 showed the anti-inflammatory effects against the activation of NF-κB induced by lipopolysaccharide (LPS) with IC50 values of 20.12, 22.89 and 68.66 µM, respectively.

Dense Polarized Positrons from Laser-Irradiated Foil Targets in the QED Regime.

Many works have shown that dense positrons can be effectively generated from laser-solid interactions in the strong-field quantum electrodynamics (QED) regime. Whether these positrons are polarized has not yet been reported, limiting their potential applications. Here, by polarized QED particle-in-cell simulations including electron-positron spin and photon polarization effects, we investigate a typical laser-solid setup that an ultraintense linearly polarized laser irradiates a foil target with micrometer-scale-length preplasmas. We find that once the positron yield becomes appreciable with the laser intensity exceeding 10^{24} W/cm^{2}, the positrons are obviously polarized. Around 30 nC positrons can acquire >30% polarization degree with a flux of 10^{12} sr^{-1}. The angle-dependent polarization is attributed to the asymmetrical laser fields that positrons undergo near the skin layer of overdense plasmas, where radiative spin flip and radiation reaction play significant roles. The polarization mechanism is robust and could generally appear in future 100-PW-class laser-solid experiments.

Research of a Safe and Simplified Intertransverse Process Approach for the Lower Thoracic Interbody Surgery.

OBJECTIVE: To assess a safe surgical approach for intertransverse process lower thoracic intervertebral body fusion (ITIF) based on measurements from enhanced three-dimensional CT reconstruction, cadaver simulated operation, and patient operation. METHODS: Enhanced three-dimensional CT image reconstruction was performed for 20 healthy volunteers on thoracic segments T8-T12. The length of the transverse process (LTP), distance between the upper and lower transverse processes (DULTP), remote distance of the transverse process (RDTP), height of the extraforaminal intervertebral space (HEIS), and oblique diameter of the intervertebral space (ODIS) were measured and recorded. The blood vessels of the intertransverse lower thoracic region were observed, and their internal diameters were measured. The rib-intervertebral space relationship for T10/11 and T11/12 was measured in 104 patients of the thoracic skeleton. Then, based on the data from the CT measurements, simulated surgery was performed on six human cadavers at the T11/12 level. An ankylosing spondylitis (AS) patient with a fracture of the T10/11 level was eventually operated on with the ITIF technique. RESULTS: No significant difference was found between the lengths of the left and right thoracic transverse processes. The relationship of the values of the LTP and RDTP for the measured vertebrae were found to be as follows:T8 > T9 > T10 > T11 > T12. For HEIS and DULTP, T8-9 < T9-10 < T10-11 < T11-12. The results for the ODIS were as follows: T8-T9 < T9-T10 < T10-T11 < T11-T12. The blood vessel inner diameter of T11-12 was less than that of T10-11, while there was no significant difference between the diameters for T8-9 and T11-12. Almost half of the volunteer's T10/11 intervertebral spaces were covered posteriorly by the 11th rib (45.19% on left and 41.35% on right), while for most patients, the T11/12 intervertebral space was not covered by the 12th rib (98.08%). According to the cadaver experiments, intervertebral bone grafting and ipsilateral pedicle screw fixation were performed to simulate the operation. One patient with a combined AS and T10/11 fracture was then operated on with the ITIF technique and followed up for 3 years with satisfactory results. CONCLUSION: As verified by 3D CT reconstruction measurements, cadaver simulation surgery and patient operation with follow-up, the intertransverse process approach for some T10/T11 and almost all T11/T12 segments is a safe surgical pathway for operations such as ITIF, fracture bone grafting, clearance of focal lesions.

Highly efficient generation of GV/m-level terahertz pulses from intense femtosecond laser-foil interactions.

The terahertz radiation from ultraintense laser-produced plasmas has aroused increasing attention recently as a promising approach toward strong terahertz sources. Here, we present the highly efficient production of millijoule-level terahertz pulses, from the rear side of a metal foil irradiated by a 10-TW femtosecond laser pulse. By characterizing the terahertz and electron emission in combination with particle-in-cell simulations, the physical reasons behind the efficient terahertz generation are discussed. The resulting focused terahertz electric field strength reaches over 2 GV/m, which is justified by experiments on terahertz strong-field-driven nonlinearity in semiconductors.

Fire Intumescent, High-Temperature Resistant, Mechanically Flexible Graphene Oxide Network for Exceptional Fire Shielding and Ultra-Fast Fire Warning.

Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings.

Two-dimensional monitoring of a laser-solid x-ray source spot via penumbral coded aperture imaging technique.

The uncertainties of spot size and position need to be clarified for x-ray sources as they can affect the detecting precision of the x-ray probe beam in applications such as radiography. In particular, for laser-driven x-ray sources, they would be more significant as they influence the inevitable fluctuation of the driving laser pulses. Here, we have employed the penumberal coded aperture imaging technique to diagnose the two-dimensional spatial distribution of an x-ray emission source spot generated from a Cu solid target irradiated by an intense laser pulse. Taking advantage of the high detection efficiency and high spatial resolution of this technique, the x-ray source spot is characterized with a relative error of ∼5% in the full width at half maximum of the intensity profile in a single-shot mode for general laser parameters, which makes it possible to reveal the information of the unfixed spot size and position precisely. Our results show the necessity and feasibility of monitoring the spot of these novel laser-driven x-ray sources via the penumbral coded aperture imaging technique.

Five new Erythrina alkaloids from the stems of Erythrina corallodendron.

Five new Erythrina alkaloids and five known E. alkaloids were isolated from a 95% ethanol extract of the stems of Erythrina corallodendron L. Their chemical structures were elucidated by UV, IR, HRESIMS, NMR and X-ray. Furthermore, the analgesic activities of E. alkaloids 1, 2 and 6 were evaluated by using an acetic acid-induced writhing test in mice, and their writhing inhibition rates were 67.9%, 64.6% and 70.3% at doses of 20 mg/kg, respectively.

New lignans and diterpenoid glycosides from the fruits of Xanthium italicum Moretti.

A pair of new lignans [(+)- 1 and (-)- 1] and three new compounds (2-4), together with a known compound 5, were isolated from the fruits of Xanthium italicum Moretti. The structures of these compounds were determined on the basis of spectroscopic analysis, particularly HR-ESI-MS and 1 D and 2 D NMR. Compounds 2 and 3 showed antinociceptive effects in an acetic acid-induced writhing test in mice with the writhe inhibition rates of 80.50% and 67.89% at the dose of 20 mg/kg, respectively.

[Research advances in methods of cyclezation mechanism of sesquiterpenes].

Terpenes are the largest group of natural products and contain the widest assortment of structural types. Terpene cyclization is also the most complex reaction found in nature. For a long time, terpenoids with diverse structures have attracted natural product chemists to explore their biosynthesis mechanism. Such a large number of terpene skeletons are catalyzed by enzymes called terpene synthase. Sesquiterpene synthase is a kind of terpene synthase, which can catalyze the cyclization of linear precursor farnesyl pyrophosphate(FPP) to sesquiterpene skeletons. Sesquiterpene synthase cyclize a single precursor FPP into many sesquiterpene skeletons. With the continuous discovery of sesquiterpene synthase, the cyclization mechanism of sesquiterpene synthase has been studied deeply. In recent years, with the development and improvement of isotope labeling of substrate FPP and structural analysis of sesquiterpene synthase, the structure and cyclization mechanism of sesquiterpene synthase have been studied more systematically and accurately. In this review, we reviewed the progress of the research methods on the mechanism of sesquiterpene cyclization by substrate isotope labeling and protein structure, as well as the summary and prospect of sesquiterpene synthase research.

[Response of Soil Archaeal Community to Heavy Metal Pollution in Different Typical Regions].

Soil archaeal communities play an essential role in the biogeochemical cycles of agricultural ecosystems. However, the response and mechanisms of soil archaeal community structure and assembly processes to heavy metal pollution remain poorly understood. This study examined the archaeal community composition and assembly process and their relationships with environmental factors in arable soils around high geological background areas, metal enterprises, and mining areas, based on high-throughput sequencing. The arable soils within the study area exhibited high spatial heterogeneity of heavy metal content, as well as severe cadmium pollution. The ecological risk levels were high in some soil samples from mining areas, but low to moderate in other soil samples. Crenarchaeota (62.7%-98.3%) was the dominant phyla in all soil samples, followed by Halobacterota (1.1%-23.2%). The pH, organic matter, arsenic, and lead contents of the soil were significantly correlated with the archaeal community (P<0.05), making them the main driving factors of archaeal community structure. The null-model analysis showed that the assembly process of the archaeal community was mainly influenced by heterogeneous processes, including heterogeneous selection (deterministic process) and dispersal limitation (stochastic process). Heterogeneous selection played a vital role in our study areas, while homogeneous selection only occurred in samples around the metal enterprises. Therefore, environmental selection was the ultimate driver of the archaeal community assembly process in this study, and its relative importance varied according to habitat type. Environmental heterogeneity increased the contribution of heterogeneous selection to community assembly, thus enhancing the community's resistance to environmental stress, and contributing to the stability and sustainability of the agricultural ecosystem.

Low-frequency whistler waves excited by relativistic laser pulses.

It is shown by multidimensional particle-in-cell simulations that intense secondary whistler waves with special vortexlike field topology can be excited by a relativistic laser pulse in the highly magnetized, near-critical density plasma. Such whistler waves with lower frequencies obliquely propagate on both sides of the laser propagation axis. The energy conversion rate from laser to whistler waves can exceed 15%. Their dispersion relations and field polarization properties can be well explained by the linear cold-plasma model. The present work presents a new excitation mechanism of whistler modes extending to the relativistic regime and could also be applied in magnetically assisted fast ignition.

Identification of a hippocampal lncRNA-regulating network in cognitive dysfunction caused by chronic cerebral hypoperfusion.

Cognitive dysfunction caused by chronic cerebral hypoperfusion is a common underlying cause of many cognition-related neurodegenerative diseases. The mechanisms of cognitive dysfunction caused by CCH are not clear. Long non-coding RNA is involved in synaptic plasticity and cognitive function, but whether lncRNA is involved in cognitive dysfunction caused by CCH has not yet been reported. In the present study, we identified the altered lncRNAs and mRNAs by deep RNA sequencing. A total of 128 mRNAs and 91 lncRNAs were up-regulated, and 108 mRNAs and 98 lncRNAs were down-regulated. Real-time reverse transcription-polymerase chain reaction verified the reliability of the lncRNA and mRNA sequencing. Gene Ontology and KEGG pathway analyses showed that differentially-expressed mRNAs were related to peptide antigen binding, the extracellular space, the monocarboxylic acid transport, and tryptophan metabolism. The co-expression analysis showed that 161 differentially expressed lncRNAs were correlated with DE mRNAs. By predicting the miRNA in which both DE lncRNAs and DE mRNAs bind together, we constructed a competitive endogenous RNA network. In this lncRNAs-miRNAs-mRNAs network, 559 lncRNA-miRNA-mRNA targeted pairs were identified, including 83 lncRNAs, 67 miRNAs, and 108 mRNAs. Through GO and KEGG pathway analysis, we further analyzed and predicted the regulatory function and potential mechanism of ceRNA network regulation. Our results are helpful for understanding the pathogenesis of cognitive dysfunction caused by CCH and provide direction for further research.

Efficacy of cystectasia in the treatment of ketamine-induced bladder contracture.

BACKGROUND: The treatment of ketamine-induced bladder contractures remains poorly studied. We therefore evaluated the efficacy of cystectasia with a sodium hyaluronate balanced solution in this kind of bladder contracture. METHODS: Eighteen patients presenting with ketamine-induced bladder contracture between July 2010 and February 2018 were selected and analysed. Ketamine was discontinued in all patients, who were then treated with weekly cystectasia (0.09% sodium hyaluronate balanced solution) 3 times. The volume of the first perfusion was twice the preoperatively measured bladder capacity, and the volume of the subsequent two perfusions was increased by 100 mL each time. The Pelvic Pain and Urgency/Frequency (PUF) symptom score, O'Leary-Sant Interstitial Cystitis (IC) Symptom Index (ICSI), IC Problem Index (ICPI), Quality of Life (QOL) score, and bladder capacity were recorded before surgery and 3 and 12 months after the 3rd expansion. RESULTS: No significant complications were observed during the 3 expansions. Fourteen patients completed the full follow-up schedule. Preoperatively and at the 3- and 12-month follow-up evaluations performed after the 3rd expansion, the PUF symptom scores were 20.4±3.6, 11.5±3.1, and 13.2±3.3, respectively; the mean ICSI was 13.6±2.8, 7.7±2.3, and 8.2±2.5, respectively; the mean ICPI was 10.6±2.6, 7.3±2.1, and 7.7±2.5, respectively; and the mean QOL scores were 6.0±0, 2.1±0.5, and 2.7±0.8, respectively; and the mean bladder catheter volume was 83±27, 234±56, and 228±52 mL, respectively. There were significant differences between all preoperative and postoperative values. CONCLUSIONS: Cystectasia with a sodium hyaluronate balanced solution is an effective treatment modality for ketamine-induced bladder contracture.

Optical steering of electron beam in laser plasma accelerators.

Using a Dazzler system and tilting a compressor grating, we provide an effective way of using the laser group delay dispersion to continuously steer the electron beam accelerated by an asymmetric laser wakefield. The deviation angle of the electron beam was the same as that of the angularly chirped laser pulse from its initial optical axis, which is determined by the laser pulse-front-tilt (PFT). This method can be utilized to continuously control over the pointing direction of electron bunches to the requisite trajectories, especially for practical applications in highly sensitive alignment devices such as electron-positron colliders or undulators. Additionally, we investigate the effect of PFT on the properties of the electron beam.

[Preliminary study of dihydroartemisin in inhibiting invasion and metastasis of hepatoma cells].

It is reported that dihydroartemisinin could reduce the expression of phosphorylated adhesion kinase and matrix metalloproteinase-2, inhibit the growth, migration and invasion of ovarian cancer cells, promote the formation of Treg cells through TGF-beta/Smad signaling pathway, and play an immunosuppressive role; dihydroartemisinin could also inhibit the growth of lung cancer cells by inhibiting the expression of vascular endothelial growth factor(VEGF) receptor KDR. However, there are few studies on dihydroartemisinin in hepatocellular carcinoma cells. In order to preliminarily explore the effect of dihydroartemisinin on invasion and metastasis of hepatocellular carcinoma cells, CCK-8 method and crystal violet staining were used to detect the effect of dihydroartemisinin on the growth of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H. The effects of dihydroartemisinin on the invasion and metastasis of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H were studied by using cell wound healing and Transwell. Western blot was used to detect the protein expression of epidermal growth factor receptor(EGFR) and its downstream signaling pathway in cells treated with dihydroartemisinin for 48 hours. The results showed that dihydroartemisinin could inhibit the growth of hepatocellular carcinoma cell 7402 and highly metastatic hepatocellular carcinoma cell MHCC97 H at 25 µmol·L~(-1). As compared with the control group, the number of cell clones was significantly reduced, and the ability of cell migration and invasion was weakened. Western blot results showed that as compared with the control group, dihydroartemisinin group could down-regulate the protein expression of EGFR and its downstream signaling pathways p-AKT, p-ERK, N-cadherin, Snail and Slug, and up-regulate the expression of E-cadherin protein, thus affecting the migration, invasion and metastasis of hepatocellular carcinoma cells 7402 and MHCC97 H.