Poly(4-styrenesulfonic acid) doped polypyrrole/tungsten oxide/reduced graphene oxide nanocomposite films based surface acoustic wave sensors for NO sensing behavior

Poly(4-styrenesulfonic acid) (PSSA) doped polypyrrole (PPy)/tungsten oxide (WO₃)/reduced graphene oxide (rGO) hybrid nanocomposite have been successfully synthesized using appropriate amounts of PSSA, pyrrole monomer, WO₃, and rGO dispersed in aqueous solution through in situ chemical oxidation polymerization. Here, a simple spin coating method was used to fabricate a nitric oxide (NO) gas sensor composed of the aforementioned nanocomposite on a surface acoustic wave (SAW) resonator. This sensor can detect NO gas at concentrations of 1–110 parts per billion (ppb) at room temperature in dry air, with a sensitivity of 12 Hz/ppb and response and recovery times of <2 min. Moreover, its limit of detection (LOD) is 0.31 ppb for a signal to noise ratio of 3. It demonstrates repeatability, fast response, and recovery at room temperature. Moreover, its sensory performance remains highly stable over 30 days with only a 6.3% decrease in sensitivity. In addition, the sensor is highly selective for NO, even when nitrogen dioxide, ammonia, and carbon dioxide are applied as interfering gases. The inclusion of rGO (with large specific surface area) and the synergic effect of n-type WO₃ nanoparticles in the p-type PPy matrix (leading to p-n heterojunction region formation) possibly underlie the efficient sensing performance of our sensor.     

改性聚乳酸发泡技术研究进展

综述了近几年国内外改性聚乳酸（PLA）发泡技术的研究进展，针对PLA在发泡方面熔体强度和结晶性能的不足，介绍了通过加入扩链剂、交联剂、成核剂、纤维和其他聚合物等物质来改善PLA发泡性能的方法、效果和机理；最后，对改性聚乳酸发泡技术的未来发展进行了展望。     

Role of the HSP70 Co-Chaperone SIL1 in Health and Disease

Cell surface and secreted proteins provide essential functions for multicellular life. They enter the endoplasmic reticulum (ER) lumen co-translationally, where they mature and fold into their complex three-dimensional structures. The ER is populated with a host of molecular chaperones, associated co-factors, and enzymes that assist and stabilize folded states. Together, they ensure that nascent proteins mature properly or, if this process fails, target them for degradation. BiP, the ER HSP70 chaperone, interacts with unfolded client proteins in a nucleotide-dependent manner, which is tightly regulated by eight DnaJ-type proteins and two nucleotide exchange factors (NEFs), SIL1 and GRP170. Loss of SIL1′s function is the leading cause of Marinesco-Sjögren syndrome (MSS), an autosomal recessive, multisystem disorder. The development of animal models has provided insights into SIL1′s functions and MSS-associated pathologies. This review provides an in-depth update on the current understanding of the molecular mechanisms underlying SIL1′s NEF activity and its role in maintaining ER homeostasis and normal physiology. A precise understanding of the underlying molecular mechanisms associated with the loss of SIL1 may allow for the development of new pharmacological approaches to treat MSS.     

Spinal Excitatory Dynorphinergic Interneurons Contribute to Burn Injury-Induced Nociception Mediated by Phosphorylated Histone 3 at Serine 10 in Rodents

The phosphorylation of serine 10 in histone 3 (p-S10H3) has recently been demonstrated to participate in spinal nociceptive processing. However, superficial dorsal horn (SDH) neurons involved in p-S10H3-mediated nociception have not been fully characterized. In the present work, we combined immunohistochemistry, in situ hybridization with the retrograde labeling of projection neurons to reveal the subset of dorsal horn neurons presenting an elevated level of p-S10H3 in response to noxious heat (60 °C), causing burn injury. Projection neurons only represented a small percentage (5%) of p-S10H3-positive cells, while the greater part of them belonged to excitatory SDH interneurons. The combined immunolabeling of p-S10H3 with markers of already established interneuronal classes of the SDH revealed that the largest subset of neurons with burn injury-induced p-S10H3 expression was dynorphin immunopositive in mice. Furthermore, the majority of p-S10H3-expressing dynorphinergic neurons proved to be excitatory, as they lacked Pax-2 and showed Lmx1b-immunopositivity. Thus, we showed that neurochemically heterogeneous SDH neurons exhibit the upregulation of p-S10H3 shortly after noxious heat-induced burn injury and consequential tissue damage, and that a dedicated subset of excitatory dynorphinergic neurons is likely a key player in the development of central sensitization via the p-S10H3 mediated pathway.     

Long-term performance analysis of chemical filters in clean rooms based on a prediction model

Chemical filters are the most important devices for removing gas-phase pollutants in clean rooms. However, the testing concentration of chemical filters is too high for reflecting their performance in a real clean room environment. This study tested the adsorption performance of chemical filters in the two most commonly used shapes at different concentrations. Then, the Langmuir equation and Wheeler-Jonas kinetic equation were combined to establish an adsorption performance prediction model of chemical filters under actual conditions. The predicted values of the model were in good agreement with the experimental results, which indicated the high accuracy of the prediction model. The model does not need to test the microscopic parameters of the adsorbent and can maintain high accuracy at low concentrations. A fast method for calculating the service life of chemical filters was also presented. Based on this model, the total cost of using a chemical filter with a high carbon content in microelectronic clean rooms could be decreased by 45% due to decreasing the number of filter replacements over 3 months. So a chemical filter with a high carbon content should be preferred over a filter with low resistance in microelectronic clean rooms.     

Real-time organic aerosol chemical speciation in the indoor environment using extractive electrospray ionization mass spectrometry

Understanding the sources and composition of organic aerosol (OA) in indoor environments requires rapid measurements, since many emissions and processes have short timescales. However, real-time molecular-level OA measurements have not been reported indoors. Here, we present quantitative measurements, at a time resolution of five seconds, of molecular ions corresponding to diverse aerosol-phase species, by applying extractive electrospray ionization mass spectrometry (EESI-MS) to indoor air analysis for the first time, as part of the highly instrumented HOMEChem field study. We demonstrate how the complex spectra of EESI-MS are screened in order to extract chemical information and investigate the possibility of interference from gas-phase semivolatile species. During experiments that simulated the Thanksgiving US holiday meal preparation, EESI-MS quantified multiple species, including fatty acids, carbohydrates, siloxanes, and phthalates. Intercomparisons with Aerosol Mass Spectrometer (AMS) and Scanning Mobility Particle Sizer suggest that EESI-MS quantified a large fraction of OA. Comparisons with FIGAERO-CIMS shows similar signal levels and good correlation, with a range of 100 for the relative sensitivities. Comparisons with SV-TAG for phthalates and with SV-TAG and AMS for total siloxanes also show strong correlation. EESI-MS observations can be used with gas-phase measurements to identify co-emitted gas- and aerosol-phase species, and this is demonstrated using complementary gas-phase PTR-MS observations.     

Preparation and desalination performance of porous planar cordierite membranes using industrial solid waste as main silica source

Silica is a main component of cordierite ceramic, in the present work, industrial solid waste was used as main silica source to prepare porous planar cordierite membranes by a solid-phase sintering process with starch as pore-forming agent. It is shown that the concentration of starch plays a critical role in the pore structure and mechanical property and the cordierite membranes with a starch concentration of 40?wt% (M-40) have a desirable pore structure and flexural strength after sintering at 1300?°C for 5?h. After grafted with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS, C₈), the ceramic membranes were used for desalination by vacuum membrane distillation (VMD). The results show that the membranes(M-40) possess an average flux of 11.43?kg/m² h, a high salt rejection of 99.9% under the following operation conditions: a NaCl concentration of 3.5?wt%, a feed rate of 300?ml/min and a temperature of 80?°C. After desalination for 120?h, the water contact angle decreases to 130°. The cordierite membranes exhibit poor resistance to thermal acid/alkali solution(boiling, pH?=?1 and 14, respectively, soaked for 8?h) but excellent resistance to ambient temperature acid/alkali solution (25?°C, pH?=?1 and 14, respectively, soaked for 120?h).     

Preparation of transparent Y2O3 ceramic via gel casting: Realization of high solid volume via surface modification

In this article, isocyanate was adopted to modify Y₂O₃ powder for the purpose of preparing transparent Y₂O₃ ceramics via gel casting. The modification could enhance the hydration resistance of Y₂O₃ powder through the steric hindrance effect. The coating mechanism can be proved by the infrared spectrum of the surface-modified Y₂O₃ powder. Modification could not only prevent Y₂O₃ particles from reacting with water, but also prevents agglomeration between particles. The viscosity of the slurry with a solid content of 52.7 vol% is only 0.48 Pa·s at the shear rate of 100 s⁻¹, which is suitable for preparing high-density compacts by gel casting. The transmittance of the sample (1840°C × 8 h, 1 mm thickness) at 1100 nm reaches 75%. The microstructure of the sintered body is dense with the average grain size of 6.5 μm without obvious impurities nor pores. Five mol% ZrO₂-doped Y₂O₃ transparent ceramic fairing with the diameter of 5 cm without defects was successfully fabricated by gel casting (52.7 vol% solid volume) and vacuum sintering (1840°C × 8 h).     

A novel and sensitive colorimetric detection of PABA by asymmetrically functionalized TA-AuNPs-PEG-FITC based on oriented aggregation

A colorimetric assay based on the oriented TA-AuNPs-PEG-FITC for rapid and sensitive PABA detection was proposed. Initially, the negatively charged TA modified on the surface of AuNPs enabled rapid binding to PABA due to the electrostatic interaction and hydrogen bond, resulting in a visible color change. However, particles were aggregated in a non-oriented way, leading to an unstable testing system which failed to realize the accurate quantification. Thus, the asymmetrically functionalized TA-AuNPs-PEG-FITC were prepared, in which the stabilizer agent of HS-PEG-FITC was attached to the specific sites on the surface of TA-AuNPs. Such a way of modification resulted in an oriented aggregation manner, the addition of PABA induced the formation of oligomers. Moreover, the introduction of FITC group acted as fluorescent marker, providing a simple, fast and quantitative method for characterization of PEG chain. The molar ratio between TA-AuNPs and modified PEG-FITC was further determined. A linear regression was established in a wide range from 10 μM to 1 mM with the LOD of 6.9 μM. Finally, the sensor was successfully applied in the health food. This was the first example in which TA-AuNPs-PEG-FITC were fabricated for colorimetric detection of PABA, and an indirect method based on fluorescence marker was well used to quantify the content of PEG chain.     

Molecule-confined modification of graphitic C3N4 to design mesopore-dominated Fe-N-C hybrid electrocatalyst for oxygen reduction reaction

To design inexpensive carbon catalysts and enhance their oxygen reduction reaction (ORR) activity is critical for developing efficient energy-conversion systems. In this work, a novel Fe-N-C hybrid electrocatalyst with carbon nanolayers-encapsulated Fe₃O₄ nanoparticles is synthesized successfully by utilizing the molecular-level confinement of graphitic C₃N₄ structures via hemin biomaterial. Benefiting from the Fe-N structure prevalent on the carbon nanosheets and large mesopore-dominated specific surface area, the synthesized catalyst under optimized conditions shows excellent electrocatalytic performance for ORR with an E_ORR at 1.08 V versus reversible hydrogen electrode (RHE) and an E_1/2 at 0.87 V vs. RHE, and outstanding long-term stability, which is superior to commercial Pt/C catalysts (E_ORR at 1.04 V versus RHE and E_1/2 at 0.84 V versus RHE). Moreover, the low hydrogen peroxide yield (<11%) and average electron transfer number (~3.8) indicate a four-electron ORR pathway. Besides, the maximum power density of the home-made Zn-air battery using the obtained catalyst is 97.6 mW cm⁻². This work provides a practical route for the synthesis of cheap and efficient ORR electrocatalysts in metal-air battery systems.