52 research outputs found
Simulation of Beef Tallow Based on Quinoa Protein-Stabilized Pickering Emulsion
In this study, high-internal phase Pickering emulsions (HIPPEs) were prepared by high speed shearing using quinoa protein isolate (QPI) as interfacial particles, corn oil as dispersed phase, and beef bone broth or beef powder solution as continuous phase, and their rheological properties, thermodynamic properties, color and volatile components were analyzed. The results showed that all 5 emulsions exhibited obvious shear thinning behavior of a pseudoplastic fluid, and their apparent viscosities decreased with the increase in shear rate. However, at the same shear rate, the emulsion with fish gelatin added to the aqueous phase showed the highest viscosity, which was more conducive to simulating the sticky taste of beef tallow. Addition of fish gelatin or starch into the aqueous phase significantly increased the storage modulus (G’), loss modulus (G”) and viscoelastic properties of Pickering emulsions, and the emulsion with fish gelatin had better viscoelastic properties and rheological properties closer to those of beef tallow than the emulsion with starch. Adding fish gelatin to the aqueous phase containing beef bone broth significantly increased the brightness and whiteness of Pickering emulsion (P < 0.05), whereas the opposite effect was observed when the aqueous phase was beef powder solution. Moreover, adding starch or fish gelatin into the aqueous phase could significantly increase the melting point of quinoa protein-stabilized Pickering emulsion. The results of gas chromatography-mass spectrometry (GC-MS) showed that using beef bone broth as the aqueous phase increased the contents of flavor components such as hexanal, 4-isopropyl toluene, and pentadecylene, imparting the emulsion with part of the flavor of beef tallow. The composition of flavor components in the emulsion with beef powder solution was similar to that in the emulsion with beef bone broth, but the content of flavor compounds was lower in the emulsion with beef powder solution than with beef bone broth. In summary, quinoa protein-stabilized Pickering emulsion with an aqueous phase containing bovine bone broth and fish gelatin showed similar rheological properties, appearance and volatile flavor composition to beef tallow, and it possessed higher melting point, showing its potential and sustained research value in simulating saturated fat
Metal Oxide Gas Sensors: Sensitivity and Influencing Factors
Conductometric semiconducting metal oxide gas sensors have been widely used and investigated in the detection of gases. Investigations have indicated that the gas sensing process is strongly related to surface reactions, so one of the important parameters of gas sensors, the sensitivity of the metal oxide based materials, will change with the factors influencing the surface reactions, such as chemical components, surface-modification and microstructures of sensing layers, temperature and humidity. In this brief review, attention will be focused on changes of sensitivity of conductometric semiconducting metal oxide gas sensors due to the five factors mentioned above
Porous hierarchical TiO2/MoS2/RGO nanoflowers as anode material for sodium ion batteries with high capacity and stability
To enhance the reversible capacity and cycle stability of MoS2 as anode materials for sodium ion batteries (SIBs), we constructed a hybrid architecture composed of MoS2 and TiO2 nanosheets, linking with reduced graphene oxide (RGO) to another TiO2/MoS2 to form a nanoflower structure. Owing to layered RGO coupled with TiO2/MoS2 hybrid, such a composite offered interconnected conductive channels to short shuttle path of Na+ ions and favorable transport kinetics under charge/discharge cycling. Moreover, this unique structure showed a porous and hierarchical architecture, which not only buffered volume changes but also provided more electrochemical active sites during insertion/deintercalation processes of Na ions. Outstanding electrochemical performances were identified by the component matching effect among TiO2, MoS2 and RGO with a three-dimensional (3D) interconnected network, exhibiting a good reversible capacity of 616 mA h g-1 after 100 cycles at 0.1 A g-1, an excellent rate capability of 250 mA h g-1 even at 5A g-1 and a long cycling stability of 460 mA h g-1 with a capacity fluctuation of 0.03% per cycle within 350 cycles at 1 A g-1
Research on ecological compensation of urban residual space to promote social integration
The continuous urbanization leads to a large number of land lost farmers pouring into the city, and the social integration of these people has become an important research topic of urban renewal. By means of field exploration and in-depth visit, this paper investigates and collates the data of some typical urban residual spaces where new industrial workers live, and finds that these spaces have common spatial characteristics, such as single spatial level, poor ecological environment and lack of landscape facilities. Then, by using statistical analysis and structural model, the comparative analysis of different types of space, and finds that the use of ecological compensation regulation can form a reasonable spatial layout, high-quality ecological effects and rich service facilities, so as to improve the spatial quality of urban residual space and provide highquality space environment for new industrial workers, Promote social integration, social integration of workers in new industries
Application of bismuth sulfide based nanomaterials in cancer diagnosis and treatment
Cancer is still the leading disease threatening human life and health at present. With the development of nanotechnology, multifunctional nanomaterials integrated with different diagnostic and therapeutic functions have become the most active field in nano-research. Among them, Bi2S3-based nanomaterials have attracted great attention in the biomedical field due to their special photothermal effect and biocompatibility. In this review, we systematically summarize the synthetic strategies and their physical-chemical properties of Bi2S3-based nanomaterials. Then we outline the recent research progress in the diagnosis and treatment of cancer, which are highlighted and discussed in detail. In addition, the safety and biodistribution of Bi2S3-based nanomaterials are emphasized and discussed. It is believed that the emerging Bi2S3-based nanomaterials may realize the practical applications via unremitting efforts of scientific researchers in the near future
Application of bismuth sulfide based nanomaterials in cancer diagnosis and treatment
Cancer is a complicated disease with a significant degree of heterogeneity, despite having made impressive advances in the field of cancer treatment, cancer remains a major threat to human life and health. The complexity of cancer on the genetic and phenotypic planes defines its clinical diversity and the difficulty of treatment. The increasing incidence of integrative types as well as individual types of cancer with the passage of time has prompted the development of novel cancer treatment strategies. Current treatment protocols are based on correcting gene mis-expression, blocking nutrient delivery to the tumor, or destroying the cancer cells. Often, surgery cannot completely eliminate all cancer cells in the body, leaving the cancer at risk of recurrence and high mortality. Chemotherapy and radiotherapy have serious side effects on normal tissue cells in the body while killing cancer cells, and these approaches are still unsatisfactory due to insufficient specificity and dose limitations. The development of novel drugs with specific targeted therapies or site-specific delivery systems to deliver therapeutic agents can greatly avoid the toxicity to healthy tissues caused by non-specificity. The preparation of nanomaterials is the most important basic technology in nanotechnology research, as well as a prerequisite for nanoapplication technology and nano-industrialization, which has been the key focus of nanotechnology researchers’ attention and research. With the development of nanotechnology, multifunctional nanomaterials, which integrate various diagnostic and therapeutic functions, have become the most active field in nanoscale research, and have been applied in the fields of early screening of tumors, identification of tumor biomarkers, targeted release of chemotherapeutic drugs and development of novel therapies. After decades of development, biomedical nanomaterials have been applied to cancer diagnosis, tumor imaging, drug loading, tumor therapy, etc. They have excellent biocompatibility and biodistribution, with advantages unmatched over traditional therapeutic methods. Among them, Bi2S3 based nanomaterials have attracted great attention in the biomedical field due to their special photothermal effect and biocompatibility, etc. The authors summarize the preparation methods of Bi2S3 based nanomaterials with different morphological dimensions reported in the literature, as well as effective strategies for constructing different heterogeneous structures. Currently, Bi2S3 based nanomaterials have been widely used in cancer diagnosis. The main strategy is the combination of various functionalized probe-loaded Bi2S3 with various imaging methods to determine tumor boundaries, histological analysis and 3D stereoscopic imaging detection. Meanwhile, due to its superior photothermal conversion efficiency and X-ray attenuation coefficient, Bi2S3 based nanomaterials have been widely used in a range of fields such as photothermal therapy, photodynamic therapy, radio sensitization therapy, immunotherapy and chemotherapy by means of rational modifications and loading. Since individual imaging modalities cannot provide complete information about the tumor treatment, Bi2S3 based nanomaterials with multimodal imaging capabilities can enable real-time monitoring of tumors and real-time observation of therapeutic agent metabolism, providing guidance for tumor treatment. In addition, a mono-therapeutic approach is often unable to completely inhibit and kill tumors, so Bi2S3 based nanomaterials integrating multiple therapeutic approaches can not only reduce the dose of chemotherapeutic drugs, but also cause serious damage to tumor cells and inhibit the metastasis of cancer cells, which greatly reduces the possibility of tumor recurrence and is of great significance for a favorable prognosis of tumor treatment. Finally, the authors highlight and discuss the biosafety and biodistribution of Bi2S3 based nanomaterials, as well as summarize methods to improve the biocompatibility of nanoparticles, providing indicative clues for further biosafety applications of Bi2S3 based nanomaterials
Dynamic Teacher’s Technology Adoption During the COVID-19 Pandemic
Understanding the teacher’s technology adoption process is essential to comprehend and narrow the digital divide in the post-epidemic age. During the pandemic, the stay-at-home orders not only intervened schooling and teaching but also increased digital accessibility to teachers. This research studies teacher heterogeneity and adoption controls in the epidemic to simultaneously affect teacher’s underlying intention and adoption behavior based on a dynamic framework under the theory of planned behavior. We present a quantitative framework for modeling the teachers’ adoption behavior of a technology conditioned on intention, defined as latent dynamic processes via a hidden Markov model. This model allows us to examine the effects of three concerned adoption controls: epidemic, community, and experience. We also explicitly characterized teachers’ digital traits as the estimated results accounts for teacher’s heterogeneity. The implicit quality of digital teaching artifacts is examined to correlate the dynamic analyses with the qualitative supports. We collected data from four primary schools in Shanghai over 173 weeks, using an after-school activity management system. The data collection spanned periods both before and after the school closure caused by the epidemic, providing us with a dynamic view of technology adoption patterns under different circumstances. Our results suggest that the interventions derived from the controls of the epidemic did not significantly narrow the digital gap. In particular, well-prepared teachers may be more sensitive to adjusting their usage to meet the evolving standards. The inexperienced teacher struggles to maintain a high level of adoption once the passive external pressure is eliminated. Even the compulsory policy can temporarily change their adoption behavior. These implications highlight the second-order digital divide problem
Rare Earth Partition Characteristics and Sedimentary Diagenetic Response in Layered Argillaceous Limestone: Taking the Shale of Upper Es4 in the Nx55 Well Area as an Example
Taking the layered argillaceous limestone in the upper Es4 in the Dongying Sag as the research object, the geochemical analysis of major, trace, and rare earth elements (REEs) established the response relationship between REE distribution characteristics and sedimentary diagenesis. The average values of total light REE (ΣLREE)/total heavy REE (ΣHREE) of micrite calcite and argillaceous laminae are 6.75 and 4.06, respectively. The LREEs and HREEs are differentiated, consistent with the distribution pattern of REEs in the crust. Th and U elements are more enriched in the sediments in the lacustrine sedimentary environment than in the diagenetic calcite veins. In primary sediments (argillaceous clay and micrite calcite laminae), LREEs are more enriched, HREEs are depleted, and Eu shows positive anomaly-enrichment characteristics. The LREEs and HREEs of the sparry calcite veins are lower than those of the original sediment argillaceous clay and micrite calcite, showing characteristics of a negative anomaly depletion. Sparry calcite veins originate from diagenetic fluid crystallization and precipitation and have the characteristics of low Th and U, evident positive anomalies of Sr and Eu, and substantial depletion of La. The distribution patterns of REEs within the four components of the laminated argillaceous sparry limestone reflect the order of REE distribution from primary sediment laminae (argillaceous clay and micrite calcite) to diagenetic laminae (calcite veins). Compared with the North American shale, the four components of the contact surface between the argillaceous and bright crystalline laminae, the micrite calcite, the calcite veins, and the argillaceous laminae all showed weak negative δCe anomalies and positive δEu anomalies. The fractionation degree between LREEs and HREEs reflected by La/Smcn and Gd/Ybcn is in descending order: the interface between the argillaceous lamina and sparry calcite lamina, micritic calcite, calcite vein, and argillaceous lamina. The argillaceous laminar material has the characteristics of basalt REEs, indicating that the terrestrial debris and argillaceous lacustrine shale in the upper Es4 member of the Niuzhuang subsag are primarily derived from the basic extrusive rocks of the Qingtuozi bulge. REE differentiation is most noticeable at the interface between the argillaceous lamina and calcite vein, proving the directionality of REE differentiation from the original sedimentary lamina to the diagenetic lamina. Shale in the study area is primarily deposited below the redox interface of water at a certain depth, and the deposition rate is stable and slow, providing good conditions for preserving organic matter
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