Enzymes in the soil are vital for assessing heavy metal soil pollution. Although the presence of heavy metals is thought to change the soil enzyme system, the distribution of enzyme activities in ...heavy metal polluted-soil is still unknown. For the first time, using soil zymography, we analyzed the distribution of enzyme activities of alfalfa rhizosphere and soil surface in the metal-contaminated soil. The results showed that the growth of alfalfa was significantly inhibited, and an impact that was most pronounced in seedling biomass and chlorophyll content. Catalase activity (CAT) in alfalfa decreased with increasing heavy metal concentrations, while malondialdehyde (MDA) content continually increased. The distribution of enzyme activities showed that both phosphatase and β-glucosidase activities were associated with the roots and were rarely distributed throughout the soil. In addition, the total hotspot areas of enzyme activities were the highest in extremely heavy pollution soil. The hotspot areas of phosphatase were 3.4%, 1.5% and 7.1% under none, moderate and extremely heavy pollution treatment, respectively, but increased from 0.1% to 0.9% for β-glucosidase with the increasing pollution levels. Compared with the traditional method of enzyme activities, zymography can directly and accurately reflect the distribution and extent of enzyme activity in heavy metals polluted soil. The results provide an efficient research method for exploring the interaction between enzyme activities and plant rhizosphere.
•The spatial pattern of rhizosphere activity is enzyme specific.•The distribution of phosphatase and β-glucosidase activities were along the roots.•The hotspot areas of enzyme activities were the highest in extremely polluted soil.•Catalase activity in alfalfa decreased with increasing heavy metal concentrations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Nitrosative/oxidative stress plays an important role in neuronal death following cerebral ischemia/reperfusion (I/R). Chrysophanol (CHR) has been shown to afford significant neuroprotection on ...ischemic stroke, however, whether its mechanism is related to attenuating nitrosative/oxidative stress is not clear. In the present study, we investigated the effect of CHR on neuronal injury related to nitric oxide (NO) production by using mouse middle cerebral artery occlusion (MCAO) model. Our results revealed that nitrite plus nitrate (NOx−) and 3-nitrotyrosine (3-NT) levels increased in ischemic brain 14 days after reperfusion, and were subsequently attenuated by CHR treatment. Moreover, 3-NT is colocalized with NeuN and TUNEL, suggesting that neuronal apoptosis following I/R is associated with 3-NT and CHR suppresses NO-associated neuronal cell death. Accordingly, cleaved caspase-3 expression in ischemic brain was decreased by CHR treatment. I/R also decreased the activity of total superoxide dismutase (SOD) and manganese-dependent SOD (MnSOD), whilst increased reactive oxygen species (ROS) production significantly. Interestingly, CHR reversed this decrease in total SOD, and MnSOD activity, and inhibited ROS generation in the ischemic brain. Taken together, our results provide direct evidence suggesting that CHR attenuates nitrosative/oxidative stress injury induced by I/R, providing a novel therapeutic target in the treatment of acute ischemic stroke.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Six rearranged 11-chaetoglobosins (1–6) were isolated from an endophytic fungus Pseudeurotium bakeri P1-1-1. Pseudeurglobosin A (1) possesses a rare 5/6/5/4/6-fused pentacyclic ring system. ...Pseudeurglobosin B (2) has a C-14–O–C-18 bridged pentacyclic 5/6/6/5/6 core. Pseudeurglobosins C–E (3–5) represent the first examples of 11-chaetoglobosins featuring a 5/6/6/7/5 ring system. Pseudeurglobosin F (6) features a unique 5/6/6 core. Compound 1 exhibited potent immunosuppressive activity against concanavalin A-induced T cell proliferation and lipopolysaccharide-induced B cell proliferation with IC50 values of 6.0 ± 0.9 and 10.8 ± 0.3 μM, respectively. Further studies revealed that 1 induced apoptosis and inhibited cytokine secretion in activated T cells through the JAK2/PI3 K/Akt signaling pathway.
Abstract
TianQin is a planned space-based gravitational wave (GW) observatory consisting of three Earth-orbiting satellites with an orbital radius of about $10^5 \, {\rm km}$. The satellites will ...form an equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between $10^{-4} \, {\rm Hz}$ and $1 \, {\rm Hz}$ that can be generated by a wide variety of important astrophysical and cosmological sources, including the inspiral of Galactic ultra-compact binaries, the inspiral of stellar-mass black hole binaries, extreme mass ratio inspirals, the merger of massive black hole binaries, and possibly the energetic processes in the very early universe and exotic sources such as cosmic strings. In order to start science operations around 2035, a roadmap called the 0123 plan is being used to bring the key technologies of TianQin to maturity, supported by the construction of a series of research facilities on the ground. Two major projects of the 0123 plan are being carried out. In this process, the team has created a new-generation $17 \, {\rm cm}$ single-body hollow corner-cube retro-reflector which was launched with the QueQiao satellite on 21 May 2018; a new laser-ranging station equipped with a $1.2 \, {\rm m}$ telescope has been constructed and the station has successfully ranged to all five retro-reflectors on the Moon; and the TianQin-1 experimental satellite was launched on 20 December 2019—the first-round result shows that the satellite has exceeded all of its mission requirements.
Atmospheric measurements showed rapid sulfate formation during
severe haze episodes in China, with fine particulate matter (PM) consisting
of a multi-component mixture that is dominated by organic ...species. Several
recent studies using the thermodynamic model estimated the particle acidity
and sulfate production rate, by treating the PM exclusively as a mixture of
inorganic salts dominated by ammonium sulfate and neglecting the effects of
organic compounds. Noticeably, the estimated pH and sulfate formation rate
during pollution periods in China were highly conflicting among the previous
studies. Here we show that a particle mixture of inorganic salts adopted by
the previous studies does not represent a suitable model system and that the
acidity and sulfate formation cannot be reliably inferred without accounting
for the effects of multi-aerosol compositions during severe haze events in
China. Our laboratory experiments show that SO2 oxidation by NO2
with NH3 neutralization on fine aerosols is dependent on the particle
hygroscopicity, phase-state, and acidity. Ammonium sulfate and oxalic acid
seed particles exposed to vapors of SO2, NO2, and NH3 at high
relative humidity (RH) exhibit distinct size growth and sulfate formation.
Aqueous ammonium sulfate particles exhibit little sulfate production, in
contrast to aqueous oxalic acid particles with significant sulfate
production. Our field measurements demonstrate significant contribution of
water-soluble organic matter to fine PM in China and indicate that the use of
oxalic acid in laboratory experiments is representative of ambient organic
dominant aerosols. While the particle acidity cannot be accurately determined
from field measurements or calculated using the thermodynamic model, our
results reveal that the pH value of ambient organics-dominated aerosols is
sufficiently high to promote efficient SO2 oxidation by NO2 with
NH3 neutralization under polluted conditions in China.
Respiratory syncytial virus (RSV), human Rhinovirus (HRV) and human Metapneumo Virus (HMPV) are important viral pathogens causing acute respiratory tract infections in the hospitalized patients. ...Sensitive and accurate detection of RSV, HRV and HMPV is necessary for clinical diagnosis and treatment.
A locked nucleic acid (LNA)-based multiplex closed one-tube nested real-time RT-PCR (mOTNRT-PCR) assay was developed for simultaneous detection of RSV, HRV and HMPV. The sensitivity, specificity, reproducibility and clinical performance of mOTNRT-PCR were evaluated and compared with individual real time PCR (RT-qPCR) assay using clinical samples. The analytical sensitivity of mOTNRT-PCR assay was 5 copies/reaction for RSV, HRV and HMPV, respectively, and no cross-reaction with other common respiratory viruses was observed. The coefficients of variation (CV) of intra-assay and inter-assay were between 0.51 to 3.67%. Of 398 nasopharyngeal aspirates samples tested, 109 (27.39%), 150 (37.69%) and 44 (11.06%) were positive for RSV, HRV and HMPV, respectively, whereas 95 (23.87%), 137 (34.42%) and 38 (9.55%) were positive for RSV, HRV and HMPV, respectively, by individual RT-qPCR assay. Thirty three samples that were positive by mOTNRT-PCR but negative by RT-qPCR were confirmed as true positives by sequencing using reported traditional two-step nested PCR assay.
mOTNRT-PCR assay reveals extremely higher sensitivity than that of RT-qPCR assay for detecting RSV, HRV and HMPV in clinical settings.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Review of Silicon Photonics Foundry Efforts Lim, Andy Eu-Jin; Junfeng Song; Qing Fang ...
IEEE journal of selected topics in quantum electronics,
2014-July-Aug., 2014-7-00, 20140701, Volume:
20, Issue:
4
Journal Article
Peer reviewed
Silicon photonics have progressed to a point where the next step for commercialization depends on the accessibility of manufacturing foundries. The implementation of a fabless foundry model using ...standardized process technology platforms is crucial for that to occur. Research and development (R&D) foundries are beginning to play bigger roles in transforming silicon photonics into a mature technology for mass production. R&D foundry services such as multi-project wafer (MPW) shuttles, customized process developmental runs and small volume manufacturing are discussed. The development of commercial foundries for low cost, high volume production is also shown to be underway, and key results from an on-going effort to set-up a manufacturing silicon photonics foundry line are presented.
The size and structure of inorganic fillers have a significant effect on the mechanical properties of dental resin composites. In this work, we report the use of spray-drying for the efficient ...construction of SiO2 colloidal nanoparticle clusters (SCNCs) as novel dental fillers, yielding spherical and closely packed structures with diameters of 1–3 μm. The superior performance of the resin composites can be obtained by filling 70 wt % SCNCs assembled with 60 nm silica colloids as building blocks in the dental resin matrix. As compared to silica microparticles with a similar average size and primary monodispersed silica nanoparticles, SCNCs have a better strengthening effect on the mechanical properties of resin composites owing to their unique nano–micro secondary structures. This spray-drying strategy enables the construction of multicomponent fillers. This is very promising for the development of multifunctional high-performance restorative resin composites.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract Many studies in metal‐organic frameworks (MOFs) aiming for high photocatalytic activity resort to self‐assembling both energy donor and acceptor building units in skeleton to achieve ...effective energy transfer, which, however, usually needs tedious synthetic procedure and design of a new MOF. In this work, we demonstrated that building a Förster resonance energy transfer (FRET) pathway can be realized through suitable molecular doping in a given MOF structure without altering the original porous structure, presenting an alternative strategy to design efficient photocatalysts for CO2 reduction. In situ electron spin resonance, ultrafast transient absorption spectroscopy, and computational studies reveal that the FRET‐induced excitation has dramatically altered the exciton transfer pathway in structure and facilitated electron‐hole separation. As a result, the molecular doped MOFs synthesized through one‐pot reaction show outstanding selectivity (96%) and activity (1314 μmol·g−1·h−1) for CO production versus almost no activity for the pristine MOFs, and this result stands out from existing competitors. Furthermore, the reaction mechanism was proposed and the intermediate signals were detected by in situ diffuse reflectance infrared Fourier transform spectroscopies. This study presents a clear picture of building FRET process in MOFs through molecular doping and provides a new design strategy for MOF‐based photocatalysts.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•Alantolactone (ATL) inhibits thioredoxin reductase (TrxR).•ATL induces generation of reactive oxygen species in HeLa cells.•ATL causes accumulation of the oxidized thioredoxin in ...cells.•Knockdown of TrxR sensitizes cells to ATL treatment.•ATL elicits oxidative stress-mediated apoptosis in HeLa cells.
The mammalian thioredoxin reductase (TrxR) isoenzymes, TrxR1 in cytosol or nucleus, TrxR2 in mitochondria, and TrxR3 in testis, are essential seleno-flavoenzymes with a conserved penultimate selenocysteine (Sec) residue at the C-terminus, and have attracted increasing interests as potential targets for development of cancer chemotherapeutic agents. The sesquiterpene lactone alantolactone (ATL), an active component from the traditional folk medicine Inula helenium, has been documented possessing multiple pharmacological functions, especially the anticancer activity. However, the underlying mechanism has not been well defined. We reported that ATL inhibits both the recombinant TrxR and the enzyme in the cellular environment. The alpha-methylene-gamma-lactone moiety in ATL and the Sec residue in TrxR are critical for targeting TrxR by ATL. By employing our newly developed pull down assay, we demonstrated the remarkable elevation of the oxidized thioredoxin in HeLa cells after ATL treatment. In addition, ATL elicits accumulation of reactive oxygen species, and eventually induces apoptosis of HeLa cells. Importantly, overexpression of the functional TrxR attenuates the cytotoxicity of ATL, while knockdown of the enzyme sensitizes the cells to ATL treatment. Targeting TrxR thus discloses a novel molecular mechanism underlying the cellular action of ATL, and sheds light in considering the usage of ATL as a potential cancer chemotherapeutic agent.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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