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To combat the ongoing public health threat of antibiotic-resistant infections, a technology that can quickly identify infecting bacterial pathogens and concurrently perform antimicrobial susceptibility testing (AST) in point-of-care settings is needed. Here, we develop a technology for point-of-care AST with a low-magnification solution scattering imaging system and a real-time video-based object scattering intensity detection method. The low magnification (1-2×) optics provides sufficient volume for direct imaging of bacteria in urine samples, avoiding the time-consuming process of culture-based bacterial isolation and enrichment. Scattering intensity from moving bacteria and particles in the sample is obtained by subtracting both spatial and temporal background from a short video. The time profile of scattering intensity is correlated with the bacterial growth rate and bacterial response to antibiotic exposure. Compared to the image-based bacterial tracking and counting method we previously developed, this simple image processing algorithm accommodates a wider range of bacterial concentrations, simplifies sample preparation, and greatly reduces the computational cost of signal processing. Furthermore, development of this simplified processing algorithm eases implementation of multiplexed detection and allows real-time signal readout, which are essential for point-of-care AST applications. To establish the method, 130 clinical urine samples were tested, and the results demonstrated an accuracy of ∼92% within 60-90 min for UTI diagnosis. Rapid AST of 55 positive clinical samples revealed 98% categorical agreement with both the clinical culture results and the on-site parallel AST validation results. This technology provides opportunities for prompt infection diagnosis and accurate antibiotic prescriptions in point-of-care settings.

Exposure to particulate matter has been associated with diseases of the respiratory and cardiovascular systems. Owing to the dense vasculature of the kidney, it has also been identified as a PM2.5 target organ. A potential contributor to PM2.5-mediated damage may be the promotion of inflammation. The essential oil 2-undecanone (2-methyl nonyl ketone) is an H. cordata isolate, and it has been shown to possess diverse pharmacologic effects, including anti-inflammatory properties. In this study we explored the ability of 2-undecanone to protect against PM2.5-induced kidney inflammation and the exact mechanisms in this process. We found that PM2.5 elevated the levels of certain inflammatory cytokines in BALB/c mice and in HEK 293 cells. Supplementation with 2-undecanone attenuated this PM2.5-induced inflammatory injury. Interestingly, in HEK 293 cells, the PM2.5-associated inflammation was aggravated by the mitophagy inhibitor Medivi-1, while it was attenuated by rapamycin, indicating that the mechanism of 2-undecanone-mediated inhibition of inflammation may relate to mitophagy. Meanwhile, 2-undecanone induces mitophagy in HEK 293 cells by suppressing Akt1-mTOR signaling. These results indicate that PM2.5 can induce kidney inflammation, and mitophagy induced by 2-undecanone may play a protective role against this renal inflammation.

A MoSi2 coating was prepared on the Mo1 wire mesh via pack cementation method, and its failure mechanisms under isothermal oxidation and hot-fire test using a hydroxylammonium nitrate based monopropellant were comparatively studied. Under isothermal oxidation at 1300 °C and 1400 °C, degradation of MoSi2 into Mo5Si3 caused failure of the coating, and interdiffusion made a much larger effect relative to oxidation. However, the MoSi2 coating failed because of the synergy of oxidation, ablation, and interdiffusion under hot-fire test. Besides, dissolution of mullite into SiO2 and ablation of high velocity flame contributed to the failure of the coating as well.

Measuring molecular binding is critical for understanding molecule-scale biological processes and screening drugs. Label free detection technologies, such as surface plasmon resonance (SPR), has been developed for analyzing the analytes in their natural forms. However, the specificity of these methods is solely relying on surface chemistry, and often have the nonspecific binding issues when working with samples in complex media. Herein, we show that single molecule based measurement can distinct specific and nonspecific binding processes by quantifying the mass and binding dynamics of individual bound analyte molecules, thus allowing the binding kinetic analysis in complex media such as serum. In addition, this single molecule imaging is realized in a commonly used Kretschmann prism coupled SPR system, thus providing a convenient solution to realize high resolution imaging on widely used prism coupled SPR systems.

Understanding the mechanisms of biodiversity maintenance is a fundamental issue in ecology. The possibility that species disperse within the landscape along differing paths presents a relatively unexplored mechanism by which diversity could emerge. By embedding a classical metapopulation model within a network framework, we explore how access to different dispersal networks can promote species coexistence. While it is clear that species with the same demography cannot coexist stably on shared dispersal networks, we find that coexistence is possible on unshared networks, as species can surprisingly form self-organised clusters of occupied patches with the most connected patches at the core. Furthermore, a unimodal biodiversity response to an increase in species colonisation rates or average patch connectivity emerges in unshared networks. Increasing network size also increases species richness monotonically, producing characteristic species-area curves. This suggests that, in contrast to previous predictions, many more species can co-occur than the number of limiting resources. Funding Agencies|National Science Foundation of ChinaNational Natural Science Foundation of China (NSFC) [31760172, 31901175]; Key Joint Youth Project of Jiangxi Province [20192ACBL21029]

Triethylamine (TEA), a typical kind of volatile organic compound, is widely used as an industrial solvent, which is a threat to environment and human health. In this paper, a novel In2O3 nanocube gas sensing material with high sensing performances was synthesized through a simple one-pot hydrothermal method. The gas sensing test results are satisfactory such that the single phase of In2O3 nanocubes even exhibits a quite higher response of 12–10 ppm of TEA at a lower temperature (180 °C) than many conventional In2O3-based complexes and maintains high consistency in morphology and stability after the consecutive tests of 2 months. This work provides a facile and quite effective gas sensing material for TEA gas monitoring with high sensitivity and stability and good selectivity at lower working temperature that can be prepared in batch and further used as templates.

The exosome-mediated response can promote or restrain the diseases by regulating the intracellular pathways, making the exosome become an effective marker for diagnosis and therapeutic control at the single-cell level. However, real-time analysis is hard to be achieved with traditional approaches because the exosomes usually need to be enriched by ultracentrifugation for a measurable signal-to-noise ratio. Recently developed label-free single-molecule imaging approaches may become an real-time quantitative tool for the analysis of single exosomes and related secretion behaviors of single living cells owing to their extreme sensitivity.

As a natural laboratory for testing various paleoclimatological and paleoceanographic hypotheses, the Pliocene-Pleistocene stratigraphic sequence from a full-coring major scientific drilling (Well CK2 with total length: 928.75 m) in Yongle atoll of Xisha Islands, northern South China Sea was studied. The Petrography of studied section of the core was dominated by reef carbonate limestones which contain abundant shallow marine organisms, e.g., coralline algae, corals, and foraminifera, which almost consisted of pure carbonates and preserved the primary geochemical message since Pliocene. According to the isolation of Well CK2 and the provenance of elements, the systematic changes and abrupt points of isotope and element geochemical compositions (rare earth element parameters, SiO2 content, Al/Ti ratio, etc.) from coral reef carbonate record presented the elevated terrigenous influences related to the East Asian monsoon after ~2.6 Ma BP, as part of the Pliocene-Pleistocene climate transition. Our results demonstrated that the continental weathering controlled by the East Asian summer monsoon dominated the surface seawater compositions of study area before ~2.6 Ma BP, when the winter monsoon was not strong enough to exert significant influences. Then, the effects of eolian dust associated with the intensity of East Asian winter monsoon, the precipitation driven by summer monsoon, and the global temperature, which played different roles at different periods after ~2.6 Ma BP, should be considered. Our results confirmed that the potentials and significances of shallow-water carbonate deposition from coral reefs, and provided a unique perspective to shed light on the carbonate record of climate changes.

Laboratory freezing experiments were conducted to evaluate the effect of polyacrylamide (PAM) and lignocellulose on the mechanical properties and microstructural characteristics of Tibetan clay. Direct shear and unconfined compressive tests and field emission scanning electron microscopy analyses were performed on clay samples with different contents of stabilizers. The test results show that the addition of PAM can improve the unconfined compressive strength and cohesion of Tibetan clay, but an excessive amount of PAM reduces the internal friction angle. After several freeze-thaw cycles, the unconfined compressive strength and cohesion of samples stabilized by PAM decrease significantly, while the internal friction angle increases. Samples stabilized by PAM and lignocellulose have higher internal friction angles, cohesion, and unconfined compressive strength and can retain about 80% of the original strength after 10 freeze-thaw cycles. PAM fills the pores between soil particles and provides adhesion. The addition of lignocellulose can form a network, restrict the expansion of pores caused by freeze-thaw cycles, and improve the integrity of PAM colloids. It is postulated that the addition of a composite stabilizer with a PAM content of 0.4% and a lignocellulose content of 2% may be a technically feasible method to increase the strength of Tibetan clay.

Rapid and sensitive detection of biomarkers is the key to the diagnosis of acute diseases. One example is the detection of troponin in myocardial infarction. Here we report a gradient-based digital immunoassay method, which can achieve high-sensitivity cardiac troponin T (hs-cTnT) detection with only 1 microliter of plasma sample. We designed a multizone microfluidic channel functionalized with capture antibody specific to troponin. Taking advantage of limited sample volume, a troponin concentration gradient is created along the channel because of binding induced depletion. We quantified the concentration gradient by counting the detection antibody conjugated gold nanoparticles bound to different test zones with optical imaging. Differential counting between the zones removes most common noises and non-specific bindings. The total analytical time is about 30 minutes, and the limit of quantification is 6.2 ng/L. We examined 41 clinical plasma samples from 15 patients and the change in hs-cTnT concentration in serial samples showed good linear correlation with clinical results (R(2) = 0.98). Therefore, this simple and sensitive gradient-based digital immunoassay method is a promising technology for clinical hs-cTnT detection and could be adapted for detection of other biomarkers.

Most label-free detection technologies detect the masses of molecules, and their sensitivities thus decrease with molecular weight, making it challenging to detect small molecules. To address this need, we have developed a charge-sensitive optical detection (CSOD) technique, which detects the charge rather than the mass of a molecule with an optical fiber. However, the effective charge of a molecule decreases with the buffer ionic strength. For this reason, the previous CSOD works with diluted buffers, which could affect the measured molecular binding kinetics. Here, we show a technique capable of detecting molecular binding kinetics in normal ionic strength buffers. An H-shaped sample well was developed to increase the current density at the sensing area to compensate the signal loss due to ionic screening at normal ionic strength buffer, while keeping the current density low at the electrodes to minimize the electrode reaction. In addition, agarose gels were used to cover the electrodes to prevent electrode reaction generated bubbles from entering the sensing area. With this new design, we have measured the binding kinetics between G-protein-coupled receptors (GPCRs) and their small molecule ligands in normal buffer. We found that the affinities measured in normal buffer are stronger than those measured in diluted buffer, likely due to the stronger electrostatic repulsion force between the same charged ligands and receptors in the diluted buffer.

Titanium alloy is a major structural material with excellent high specific strength in aerospace applications. Cubic boron nitride (cBN) is a synthetic wear-resistant material with high hardness, similar to that of diamond, that is used in mechanical cutting and grinding. In addition, the thermal stability of cubic boron nitride particles is much better than that of diamond. In order to further enhance the wear resistance of the Ti6Al4V alloy, the laser cladding (LC) technology characteristics of metallurgical bonding were used to prepare cubic boron nitride/Ti6Al4V and Ni-plated cubic boron nitride/Ti6Al4V composite coatings on Ti6Al4V substrates in this paper. However, in the laser molten pool, it is difficult to retain the raw properties of cubic boron nitride particles under laser radiation. Both composite coatings were analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The microstructures and interface bonding between cubic boron nitride particles and the Ti6Al4V matrix were examined using SEM, and the wear resistance and the worn track morphology of the composite coatings were evaluated using the ball-on-disc wear test and step profiler (WTM-2E). The results indicated that the Ni-plated cubic boron nitride/Ti6Al4V composite coating showed fewer thermal defects in comparison with the cubic boron nitride/Ti6Al4V coating. The Ni plating on the surface of cubic boron nitride particles was able to avoid the generation of thermal cracking of the cubic boron nitride particles in the composite coating. The TiN reaction layer was formed between the cubic boron nitride particles and Ti6Al4V matrix, which effectively prevented the further decomposition of the cubic boron nitride particles. The XRD and XPS results confirmed that the TiN reaction layer formed between the cubic boron nitride particles and Ti6Al4V. The Ni plating on the surface of the cubic boron nitride particles was also beneficial for increasing the wear resistance of the composite coating.

Patulin (PAT), a kind of mycotoxin, is produced by many common fungi in fruit and vegetable-based products. It has been shown to cause hepatotoxicity. However, the possible mechanisms are not completely elucidated. The present study aimed to characterize the role of autophagic-inflammasomal pathway on pyroptosis induced by PAT. In mouse livers, PAT induced pyroptosis, and increased inflammation through the activation of NLRP3 inflammasome. In liver cells, we noticed that PAT induced pyroptotic cell death, which was confirmed by the activation of GSDMD, caspase-1, the release of LDH, and the result of PI/Hoechst assay. In addition, PAT-induced pyroptosis was dependent upon the activation of NLRP3 inflammasome and the release of cathepsin B. Cells had less expression of caspase-1 and IL-1β protein levels after treated by NLRP3 inhibitor MCC950 or cathepsin B inhibitor CA-074Me. The expression of GSDMD and IL-1β protein levels were also decrease after treated by caspase-1 inhibitor Ac-YVAD-cmk. Moreover, autophagy inhibitor 3-methyladenine (3-MA) attenuated PAT-induced increase in cytoplasmic cathepsin B expression, and subsequent LDH release, the activation of NLRP3 inflamosomes, pyroptotic cell death, and inflammation. These findings suggested that PAT-induced pyroptosis maybe through autophagy-cathepsin B-inflammasomal pathway in the liver. These results provide new mechanistic insights into PAT-induced hepatotoxicity.

A rapid and sensitive method to detect cardiac troponin I (cTnI) in human blood is critical to the diagnosis and treatment of acute myocardial infarction (AMI). Here, we describe a simple one-step digital immunoassay for single-molecule detection without washing steps. A sample containing cTnI mixed with detection antibody-conjugated gold nanoparticles (AuNPs) is added to a capture antibody-coated sensor surface and the formation of the antibody-cTnI-antibody sandwich is detected by digitally counting the binding of the individual gold nanoparticles to the sensor surface in real time using a bright-field optical imaging setup together with a differential imaging algorithm. The digital immunoassay detects cTnI in undiluted human plasma, which achieves a detection limit of 5.7 ng/L within a detection time of only 10 min, which meets the requirement of current clinical high-sensitivity troponin assay (∼70 ng/L cutoff). We anticipate that the one-step and real-time digital immunoassay can be applied to the detection of other disease biomarkers in blood.

Membrane proteins play vital roles in cellular signaling processes and serve as the most popular drug targets. A key task in studying cellular functions and developing drugs is to measure the binding kinetics of ligands with the membrane proteins. However, this has been a long-standing challenge because one must perform the measurement in a membrane environment to maintain the conformations and functions of the membrane proteins. Here, we report a new method to measure ligand binding kinetics to membrane proteins using self-assembled virion oscillators. Virions of human herpesvirus were used to display human G-protein-coupled receptors (GPCRs) on their viral envelopes. Each virion was then attached to a gold-coated glass surface via a flexible polymer to form an oscillator and driven into oscillation with an alternating electric field. By tracking changes in the oscillation amplitude in real-time with subnanometer precision, the binding kinetics between ligands and GPCRs was measured. We anticipate that this new label-free detection technology can be readily applied to measure small or large ligand binding to any type of membrane proteins and thus contribute to the understanding of cellular functions and screening of drugs.

Microplastics sorption of persistent organic pollutants (POPs) was the core processes that cause negative effects to biota, and their influencing factors and related mechanisms are poorly understood. In this study, we explored the impacts of water extractable organic matter (WEOM), an important source of endogenous dissolved organic matter in mangrove sediment, on the sorption coefficients of typical parent, alkyl and N/O/S-containing polycyclic aromatic hydrocarbons (PAHs) by microplastics. The presence of L-WEOM (D) impeded the PAHs sorption as the coefficients (Kf) decreased to 10.17 (μg/kg)/(μg/L)n and to 8.39 (μg/kg)/(μg/L)n for fluorene (Flu) and 1-methyl-fluorene (1-M-Flu), respectively. The Kf exhibited good linear relationships with the aliphaticity of L-WEOM (p 0.05). Under the presences of L-WEOM (D), (S) and (K), the lone pair electrons of N/O/S-containing PAHs was the dominant factor contributing to the obvious difference of the Kf values from the other groups. Moreover, the largest impact of L-WEOM (D) on the Flu sorption was in the case of PVC microplastics, while almost no effect was in the case of PS microplastics. The findings of our work may be helpful in improving our understanding of the role of WEOM on the sorption of PAHs to microplastics in the field mangrove sediment.

Patulin (PAT) is a secondary metabolite produced by certain species of Penicillium, Byssochlamys and Aspergillus. It has been shown to induce liver toxicity, but the possible molecular mechanisms are not completely elucidated. In our study, we treated Human Hepatoma G2 (HepG2) cells by 3-methyladenine (3-MA), an autophagosome formation inhibitor, and rapamycin, an autophagosome formation stimulator. The results showed that 3-MA protected the HepG2 cells against PAT cytotoxicity, while rapamycin decreased the cell viability. Thus, autophagy may play an important role in PAT-induced toxicity. To uncover the mechanism by which cells decrease proliferation and activation of autophagy, we found that collapses of mitochondrial membrane potential (ΔΨm) and reactive oxygen species (ROS) level were increased under treatment with PAT. Further, we elucidated that the expression of p-Akt1 and p-MTOR was inhibited during this process. N-acetyl-l-cysteine (NAC), a ROS inhibitor, protected against PAT-induced cytotoxicity, decreased the protein expression of LC3-II, and up-regulated the level of p-Akt1 and p-MTOR. These findings suggested that PAT-induced autophagic cell death was ROS-dependent in HepG2 cells. In conclusion, it is possible that PAT elicited autophagy through ROS-Akt1-MTOR pathway in the HepG2 cells.

The ZnO/g-C3N4 binary heterostructures were formed by two steps, then the firm connection between ZnO NRs and lamellar g-C3N4 was characterized through powder XRD, FESEM with EDS, TEM, XPS, and Thermogravimetric analysis. Then the gas sensing performances of ZnO/g-C3N4 nanoheterostructures were analyzed systematically by using ethanol as a molecular probe. The results revealed that the fabricated compositive sensor not only exhibited quick response/recovery characteristics in the whole operating temperature (OT) range of 200–300 °C but also got a maximum response of 14.29 toward 100 ppm of ethanol at the optimal OT of only 260 °C. Moreover, such heterostructures also demonstrated good selectivity and superb reproducibility to acetone among all the tested toxic gases, especially higher response and faster response-recovery speeds than the pristine ZnO sensor. The above ZnO/g-C3N4 heterostructures may also supply other novel applications in the aspects of lithium-ion batteries, photocatalysis, optical devices, and so on.

A novel approach for in vivo determination of typical N/O/S-containing PAHs located on the epidermis of mangrove roots was developed using graphene quantum dots (GQDs) as a fluorescence quencher. The decreasing fluorescence intensity from GQDs was attributed to the amount of N/O/S-containing PAHs introduced onto the epidermis of mangrove roots. The linear ranges of the proposed method were 10.3-980ngg-1, 9.5-1350ngg-1 and 7.8-1200ngg-1 for DBF, DBT and CAR located on the epidermis of K. obovata roots, respectively. This method was also shown to be valid for quantifying the N/O/S-containing PAHs on the root epidermis in the presence of heavy metal (10mmolL-1) and dissolved organic matter (1mgL-1 C). Moreover, the death rates of epidermal cells were almost unchanged (p>0.05) after acquiring the fluorescence spectra, which is superior to the previously reported LITRF method with which the cell death rates increased to 42.6%.

As a kind of tropical agricultural solid waste, cassava dregs had become a thorny nonpoint source pollution problem. This study investigated the feasibility of applying cassava dregs as a substitute for sucrose in biofloc technology (BFT) systems. Three types of biofloc systems (using three different carbon sources sucrose (BFT1), cassava dregs (BFT2) and enzyme-hydrolyzed cassava dregs (BFT3) respectively), and the control were constructed in this experiment in 200L tanks with a C/N ratio of 20/1. The comparison of the water quality indicators (The total ammonia nitrogen (TAN), nitrite (NO2--N), nitrate (NO3--N), chemical oxygen demand (COD)), biofloc for the above four groups was performed, and the results indicated that BFT3 showed greater potential to the formation of biofloc, which was beneficial for the water quality control. So the shrimp survival rate was the highest and the feed conversion rate was the lowest in BFT3. Besides, the high-throughput sequencing results showed that the relative abundance of heterotrophic bacteria in the top 30 dominant microbial communities in BFT3 was higher than those in BFT1 and BFT2 by 20.70% and 1.19%, respectively, which could decrease TAN to improve the water quality. Overall, the results had proved that the cassava dregs of enzymes hydrolysis could be used as an ideal and cheap carbon source in BFT.

The retention of CdS/ZnS QDs on the epidermis has been confirmed to be one of the core procedures during the root uptake process. However, the retention mechanisms of QDs on the epidermis of woody plant were poorly understood for lacking of an appropriate QD quantitative method. In this study, a novel method for in situ determination of CdS/ZnS QDs retained on the root epidermis was established using synchronous nanosecond time-resolved fluorescence spectroscopy. No correlations between Kf values of oleylamine-CdS/ZnS QDs retained on the epidermal tissues and the surface/bulk composition of mangrove root were observed (p > 0.05) due to the existence of endocytosis mechanisms during the QD uptake processes. Moreover, the difference of the CdS/ZnS QDs in water and further translocated to xylem/phloem of root rather than the combination with cell wall/membranes was the predominant reason that caused the Kf values to follow the sequence of PEG-COOH-CdS/ZnS QDs < PEG-NH2-CdS/ZnS QDs ≪ oleylamine-CdS/ZnS QDs.

Sensitivity is a challenging issue for most gas sensors in detecting volatile organic compounds (VOCs). In this study, an alternative ethanol chemosensor based on In2O3@N-C nanospheres (NSs) was synthesized successfully through a simple vapor-phase method. The In2O3@N-C NSs structure, morphology and chemical states were characterized by XRD, SEM, TEM (HRTEM), XPS, and PL measurements. The gas sensor based on In2O3@N-C NSs showed high sensitivity for a wide range of ethanol concentrations (0.5–200 ppm). The N-C shell increased the concentration of oxygen vacancies, thereby increasing the number of active sites as verified by XPS and PL. We investigated the effect of the N–C shell on gas sensitivity. Compared with the pure In2O3 sensor, the In2O3@N-C NS sensor exhibited significantly enhanced sensing performance toward ethanol with a response to 100 ppm ethanol was approximately 145, at least seven times higher than the other gases and two times higher than the pure In2O3 NS sensor (83). As the relative humidity increased, the sensor sensitivity decreased. However, even under a high humidity environment of 70%, the response of the In2O3@N-C NS sensor was still above 20. Our results indicated that In2O3@N-C NSs are prospective candidates for ethanol gas sensor fabrication.

The dissolution evolution behavior and dissolution mechanism of cellulose in N -methylmorpholine- N -oxide (NMMO)/H 2 O solution, a typical aqueous solvent, were investigated. The dissolution evolution behaviors and hypothesis were characterized by polarizing microscope (POM) and Wide-angle X-ray diffraction (WAXD). Results showed that the concentration of the solvent penetrating into the native cellulose increases gradually, special swelling dissolution of different cellulose fibers is caused by the inconsistency of the structure and or composition of the fibers. The dissolving process of cellulose with the structure of amorphous regions co-existing with crystalline regions is that the solvent penetrates in the amorphous regions and weak regions where the structure is loose, causing the crystalline regions of compact structure gradual dispersing from outer to inner by the chain disentanglement of these regions, and further developed the model for the dissolving evolution behaviors of polymer with the structure of amorphous co-existing with crystalline regions and the solvent penetrating model for the swelling dissolution of cellulose fiber.

Programmable remodelling of cell surfaces enables high-precision regulation of cell behavior. In this work, we developed in vitro constructed DNA-based chemical reaction networks (CRNs) to program on-chip cell adhesion. We found that the RGD-functionalized DNA CRNs are entirely noninvasive when interfaced with the fluidic mosaic membrane of living cells. DNA toehold with different lengths could tunably alter the release kinetics of cells, which shows rapid release in minutes with the use of a 6-base toehold. We further demonstrated the realization of Boolean logic functions by using DNA strand displacement reactions, which include multi-input and sequential cell logic gates (AND, OR, XOR, and AND-OR). This study provides a highly generic tool for self-organization of biological systems.

Habitat destruction, characterized by patch loss and fragmentation, is a major driving force of species extinction, and understanding its mechanisms has become a central issue in biodiversity conservation. Numerous studies have explored the effect of patch loss on food web dynamics, but ignored the critical role of patch fragmentation. Here we develop an extended patch-dynamic model for a tri-trophic omnivory system with trophic-dependent dispersal in fragmented landscapes. We found that species display different vulnerabilities to both patch loss and fragmentation, depending on their dispersal range and trophic position. The resulting trophic structure varies depending on the degree of habitat loss and fragmentation, due to a tradeoff between bottom-up control on omnivores (dominated by patch loss) and dispersal limitation on intermediate consumers (dominated by patch fragmentation). Overall, we find that omnivory increases system robustness to habitat destruction relative to a simple food chain.

In this study, novel cellulose/polyvinyl alcohol (PVA) composite hydrogel membranes were prepared by means of immersion-precipitation phase transformation, using the ionic liquid 1-butyl-3-methylimidazolium acetate ([C4mim]+Ac−) as a solvent. The cellulose/PVA composites were characterized by UV-visible light absorption spectroscopy (UV), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction measurements (XRD) and scanning electron microscopy (SEM). The results revealed that a novel compact dual-network structure was formed between the cross-linked cellulose network and PVA. With an increase of cellulose in the composites, the tensile strengths of the composite hydrogel membranes were greatly increased as expected. As PVA was added, the swelling and water-absorbing properties of the cellulose/PVA hydrogels were significantly improved. In addition, the possible formation mechanism of the composite hydrogel was also discussed. It is believed that this is an effective method to prepare novel composite hydrogel materials.

The CRISPR/Cas9 system is a creative and innovative gene editing biotechnology tool in genetic engineering. Although several achievements have been attained using the CRISPR/Cas9 system, it is still a challenge to avoid off-target effects and improve the editing efficacy. Previous efforts on evaluating the efficacy and designing the guide RNA mainly focused on DNA properties. However, some DNA features have not been characterized but can be reflected by protein properties, such as the disorder features and the sequence conservation. In this paper, we provided a computational framework to identify important features related to the efficacy of CRISPR/Cas9 focusing on the properties of the proteins encoded by the target DNA fragments. The feature selection method, maximal-relevance-minimal-redundancy, was adopted to analyze these features. And incremental feature selection together with support vector machine, were employed to extract optimal features, on which an optimal classifier can be constructed. As a result, 152 important features were extracted, with which an optimal classifier based on support vector machine was built. This classifier obtained the highest MCC value of 0.355. Finally, a series of detailed biological analyses were performed on the optimal features. From the results, we found that some key factors may differentially affect the binding activity of sgRNAs to their targets. Among them, the disorder status of the target protein sequences was found to be a major factor that is related to the efficacy of sgRNAs, suggesting the DNA features associated with the protein disorder status could also affect the CRISPR/Cas9 efficacy.

Mono (2-ethylhexyl) phthalate (MEHP) is the principal metabolite of di (2-etylhexyl) phthalate, which is widely used as a plasticizer, especially in medical devices. MEHP has toxic effects on cardiovascular system. The aim of this study was to investigate the possibility that 6-gingerol may inhibit the oxidative DNA damage of MEHP in human umbilical vein endothelial cells (HUVECs) and the potential mechanism. The comet assay was used to monitor DNA strand breaks. We have shown that 6-gingerol significantly reduced the DNA strand breaks caused by MEHP. MEHP increased the levels of reactive oxygen species and malondialdehyde, decreased the level of glutathione and activity of superoxide dismutase, and altered the mitochondrial membrane potential. In addition, DNA damage-associated proteins (p53 and p-Chk2 (T68)) were significantly increased by the treatment of MEHP. Those effects can all be protected by 6-gingerol. The results firmly indicate that 6-gingerol may have a strong protective ability against the DNA damage caused by MEHP in HUVECs, and the mechanism may relate to the antioxidant activity.

Measuring ligand-protein interactions is critical for unveiling molecular-scale biological processes in living systems and for screening drugs. Various detection technologies have been developed, but quantifying the binding kinetics of small molecules to the proteins remains challenging because the sensitivities of the mainstream technologies decrease with the size of the ligand. Here, we report a method to measure and quantify the binding kinetics of both large and small molecules with self-assembled nano-oscillators, each consisting of a nanoparticle tethered to a surface via long polymer molecules. By applying an oscillating electric field normal to the surface, the nanoparticle oscillates, and the oscillation amplitude is proportional to the number of charges on the nano-oscillator. Upon the binding of ligands onto the nano-oscillator, the oscillation amplitude will change. Using a plasmonic imaging approach, the oscillation amplitude is measured with subnanometer precision, allowing us to accurately quantify the binding kinetics of ligands, including small molecules, to their protein receptors. This work demonstrates the capability of nano-oscillators as an useful tool for measuring the binding kinetics of both large and small molecules.

Metal oxide hetero-nanostructures have widely been used as the core part of chemical gas sensors. To improve the dispersion state of each constituent and the poor stability that exists in heterogeneous gas sensing materials, a uniaxial electro-spinning method combined with calcination was applied to synthesize pure SnO2 and three groups of WO3/SnO2 (WO3 of 0.1, 0.3, 0.9 wt%) hetero-nanofibers (HNFs) in our work. A series of characterizations prove that the products present hollow and fibrous structures composed of even nanoparticles while WO3 is uniformly distributed into the SnO2 matrix. Gas sensing tests display that the WO3/SnO2 (0.3 wt%) sensor not only exhibits the highest response (30.28) and excellent selectivity to acetone vapor at the lower detection temperature (170°C), 6 times higher than that of pure SnO2 (5.2), but still achieves a considerable response (4.7) when the acetone concentration is down to 100 ppb with the corresponding response/recovery times of 50/200 s, respectively. Such structure obviously enhances the gas sensing performance toward acetone which guides the construction of a highly sensitive acetone sensor. Meanwhile, the enhancement mechanism of such a special sensor is also discussed in detail.

The emergence of antibiotic resistance has prompted the development of rapid antimicrobial susceptibility testing (AST) technologies that will enable evidence-based treatment and promote antimicrobial stewardship. To date, many rapid AST methods have been developed, but few are able to be performed on clinical samples directly. Here we developed a large volume light scattering microscopy (LVM) technique that tracks phenotypic features of single bacterial cells directly in clinical urine samples without sample enrichment or culturing. The technique demonstrated rapid (90 min) detection of Escherichia coli in 24 clinical urine samples with 100% sensitivity and 83% specificity and rapid (90 min) AST in 12 urine samples with 87.5% categorical agreement with two antibiotics, ampicillin and ciprofloxacin.

Nitrogen biogeochemistry occupies a central role in nitrogen cycles and exerts a significant influence on primary productivity and global carbon cycles. In order to better understand the nitrogen biogeochemistry in coastal regions, spatiotemporal nitrogen fixation, denitrification and anammox were investigated in the coastal regions of northern Beibu Gulf (NBG), South China Sea (SCS). Nitrogen fixation was mainly detected in the water column of outer bays, attributed to the low nitrate concentration and low N/P (N/P 16). Comparisons of the nitrogen fixation rates between unicellular (10 mm) and the filamentous diazotrophs (10 mm) indicated that the contribution of unicellular diazotrophs was more important than filamentous diazotrophs. Besides, field investigation revealed that Richelia was the dominant species in filamentous diazotrophs. On the other hand, both denitrification and anammox were found in the surface sediment and denitrification dominated the nitrogen loss process. Denitrification was mainly related to the nitrate concentration in pore water and organic matter in the sediment, while anammox was mainly regulated by the concentration of nitrate and nitrite in pore water. Additionally, temperature, dissolved oxygen (DO) and salinity also had an impact on denitrification and anammox. The net areal yield of nitrogen biogeochemical processes was estimated to be -1079t/a, as an important pathway of nitrogen removal. This study adds to the knowledge of nitrogen biogeochemistry in the nutrient-replete coastal region and highlights its significance in such an environment.

Human G protein-coupled receptors (GPCRs) respond to various ligands and stimuli. However, GPCRs rely on membrane for proper folding, making their biochemical properties difficult to study. By displaying GPCRs in viral envelopes, we fabricated a Virion Display (VirD) array containing 315 non-olfactory human GPCRs for functional characterization. Using this array, we found that 10 of 20 anti-GPCR mAbs were ultra-specific. We further demonstrated that those failed in the mAb assays could recognize their canonical ligands, suggesting proper folding. Next, using two peptide ligands on the VirD-GPCR array, we identified expected interactions and novel interactions. Finally, we screened the array with group B Streptococcus, a major cause of neonatal meningitis, and demonstrated that inhibition of a newly identified target, CysLTR1, reduced bacterial penetration both in vitro and in vivo. We believe that the VirD-GPCR array holds great potential for high-throughput screening for small molecule drugs, affinity reagents, and ligand deorphanization., G protein-coupled receptors (GPCRs) are important targets for drug discovery. Here, the authors develop a Virion Display array of 315 functional non-odorant GPCRs, providing a platform for high-throughput, unbiased screening for small molecule drugs, affinity reagents, and microbial interactions.

Aluminium layers were coated onto the surface of pure titanium using hot-dip aluminising technology, and then the aluminium layers were in situ oxidised to form oxide ceramic coatings, using the micro-arc oxidation (MAO) technique. The microstructure and composition distribution of the hot-dip aluminium coatings and ceramic layers were studied by using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase structure of the MAO layers was studied using X-ray diffraction. The surface composition of the MAO layer was studied by X-ray photoelectron spectroscopy. The wear resistance of the pure titanium substrate and the ceramic layers coated on its surface were evaluated by using the ball-on-disc wear method. Therefore, aluminising coatings, which consist of a diffusion layer and a pure aluminium layer, could be formed on pure titanium substrates using the hot-dip aluminising method. The MAO method enabled the in-situ oxidation of hot-dip pure aluminium layers, which subsequently led to the formation of ceramic layers. Moreover, the wear resistance values of the ceramic layers were significantly higher than that of the pure titanium substrate.

A method for optical imaging of single protein molecules including tethering single protein molecules via a flexible polymer linker to a glass slide having a surface coated with an indium tin oxide (ITO) so that the single protein molecules are tethered to the coated surface. The single protein molecules are driven into oscillation by applying an alternating electric field to the coated surface and the glass slide is located in the field of view of an objective lens. Incident light is directed onto the coated surface from an angle to generate an evanescent field and produce scattered light. The scattered light is collected and imaged by a CMOS imager to record a sequence of images of the scattered light. A Fast Fourier Transform (FFT) filter is applied to each pixel of the recorded image sequence to produce an oscillation amplitude image from which size, charge, and mobility of the plurality of single protein molecules can be determined.

G protein-coupled receptors (GPCRs) are the largest protein family for cell signal transduction, and most of them are crucial drug targets. Conventional label-free assays lack the spatial information to address the heterogeneous response from single cells after GPCRs activation. Here, we reported a GPCRs study in live cells using plasmonic-based electrochemical impedance microscopy. This label-free optical imaging platform is able to resolve responses from individual cells with subcellular resolution. Using this platform, we studied the histamine mediated GPCRs activation and revealed spatiotemporal heterogeneity of cellular downstream responses. Triphasic responses were observed from individual HeLa cells upon histamine stimulation. A quick peak P1 in less than 10 s was attributed to the GPCRs triggered calcium release. An inverted P2 phase within 1 min was attributed to the alternations of cell-matrix adhesion after the activation of Protein Kinase C (PKC). The main peak (P3) around 3-6 min after the histamine treatment was due to dynamic mass redistribution and showed a dose-dependent response with a half-maximal effective concentration (EC50) of 3.9 ± 1.2 μM. Heterogeneous P3 responses among individual cells were observed, particularly at high histamine concentration, indicating diverse histamine H1 receptor expression level in the cell population.

To better understand cell behaviors on substrates, the precise control of density and orientation of cell-specific ligands remains a great challenge. In this study, we established an easy-to-use approach to manipulate the adhesion and patterning of mammalian cells on gold substrates. We prepared DNA self-assembled monolayers (DNA-SAMs) on gold substrates and found that the sequence-specific orientation of DNA-SAMs played an important role in modulating cell adhesion. We also found that the DNA-SAMs on gold substrates could be used as a potentially universal cell culture substrate, which showed properties similar to cationic polymers (e.g. poly-L lysine, PLL) substrates. Furthermore, we could manipulate cell adhesion by tuning the length of poly adenine (polyA) in the DNA sequence. We also prepared a DNA aptamer-based SAM to regulate cell adhesion by exploiting stimuli-responsive conformational change of the aptamer. By using the well-established DNA spotting technology, we patterned cells on DNA-SAMs to form a spot matrix and four English letters “CELL”. Our findings suggest that DNA-SAMs on gold substrates are potentially useful for making smart surfaces for cell studies, thus introducing a new platform for cell/tissue engineering research.

A hot-dip aluminised layer was prepared on a Mo1 substrate and the obtained layer was oxidised in situ by a micro-arc oxidation (MAO) technique to form an oxide ceramic coating. The obtained hot-dip aluminised layer had a two-layer structure overall: the outer layer was a pure aluminium layer, and the inner layer was a diffusion layer. The hot-dip aluminising temperature directly influenced the structure and phase composition of the obtained diffusion layer. The diffusion layer of the hot-dip aluminised layer at 710 °C was divided into three layers. The inner, intermediate, and outer layers were mainly composed of Al8Mo3, Al4Mo, and Al12Mo phases, respectively. The diffusion layer of the hot-dip aluminised layer at 750 °C was divided into two layers: the inner layer was mainly composed of an Al8Mo3 phase, and the outer layer of Al4Mo. After the hot-dip aluminised layer was treated by MAO, a three-layer coating was obtained. The outer layer was a ceramic one obtained by MAO, which was mainly composed of Al2O3, mullite, and unoxidized aluminium. The middle one was pure aluminium obtained by hot-dip aluminising and without MAO. The inner layer was an Al–Mo diffusion layer.

The stabilization of heavy metals (zinc and chromium) and the degradation of organic pollutants during supercritical water (SCW) and supercritical water oxidation (SCWO) treatment of electroplating sludge (EPS) with a high iron content were studied. Experiments were performed in a batch reactor at temperatures in the range from 623.15 to 823.15 K with an oxygen coefficient (OE) from 0 to 2.0, a reaction time of 7 min and pressure of 25 MPa to examine the effect of the operation conditions. Chemical oxygen demand (COD) and total organic carbon (TOC) in raw sludge and liquid products under different reaction conditions were detected. The results indicated that more organic pollutant degradation occurred under supercritical conditions than in subcritical water. Additionally, as the temperature and amount of oxidant increased, the organic pollutant removal rate increased. In addition, the Zn and Cr removal efficiency from sludge was more than 98% under all conditions. Temperatures under 773.15 K had a positive effect, whereas the oxygen ratio was more significant than the other factors above 773.15 K. Furthermore, leaching toxicity tests of the heavy metals in solid products were conducted based on the toxicity characteristic leaching procedure (TCLP). All heavy metals showed greatly reduced leaching toxicity due to their stabilization. The Zn in the EPS is more easily converted into a solid product after SCWO treatment; however, Cr is more difficult to leach from the solid product. Oxides of iron, zinc, and chromium were detected by X-ray diffraction and an electron probe microanalyzer, and the yield of the oxides increased with increasing temperature and oxidant amount. Using the obtained data and analysis results, the effect of Fe on the stabilization of Zn and Cr was studied.

Patulin (PAT) is a compound produced by fungi including those of the Aspergillus, Penicillium, and Byssochlamys species. PAT has been linked with negative outcomes in certain microorganisms and animal species, but how it causes hepatotoxicity is poorly understood. In this study, we determined that, by treating HepG2 cells using PAT, these cells could be induced to rapidly undergo autophagy, and this was followed within 12 h of treatment by lysosomal membrane permeabilization (LMP) and cathepsin B release. We were able to block these outcomes if cells were treated with 3-methyladenine (3MA), an inhibitor of autophagy, prior to PAT treatment. Moreover, PAT-induced collapse of mitochondrial membrane potential (ΔΨm) depended both on cathepsin B and autophagy. 3MA was further able to reduce the induction of apoptosis in response to PAT, suggesting that autophagy is a driving mechanism for this apoptotic induction. Inhibiting cathepsin B using CA-074 Me further reduced PAT-induced collapses of ΔΨm, mitochondiral cytochrome c release, and apoptosis. We also found that extended treatment of HepG2 cells using PAT over a period of 24 h led to the impairment of mitophagy such that morphologically swollen mitochondria accumulated within cells, and PINK1 failed to colocalize with LC3. Together these data reveal that PAT treatment can promote the induction of apoptosis in HepG2 cells in a manner dependent upon autophagy that progresses via the lysosomal-mitochondrial axis. This study thereby affords new insights into the mechanisms by which PAT drives hepatotoxicity.