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Wooden vats are used in the production of some traditional cheeses as the biofilms on wooden vat surfaces are known to transfer large quantities of microbes to cheese. However, very few studies have investigated the microbial composition of biofilms on newly developed wooden vats and how communities assemble and evolve. In the present study, the microbial communities of biofilms were characterized over the activation process on new wooden vats using amplicon sequencing of bacterial 16s rRNA and fungal internal transcribed spacer genes. Results showed that microbes from the whey effectively developed on wooden vats. Lactococcus was highly dominant throughout the vat activation process with substantial increases in the relative abundance of Acetobacter and Lactobacillus at the end of the vat activation (day 7). This was in contrast with fungal communities that stabilized early (day 1) and were dominated by Kluyveromyces. Predicted functions corresponded with the different stages of biofilm formation whereby functions associated with biofilm initiation were enriched on day 1 and those associated with growth and maturation were enriched on days 4 and 7. Microbial succession on wooden vat surfaces is expected to be reproducible based on the early onset and dominance of the deterministic process.

Carbon nanodots (C-dots) have gained much attention due to their unique optical and physicochemical properties. Herein, C-dots with uniform size have been fabricated via an in situ pyrolysis of dipropylamine (DPA) organic amines confined in the channels of SAPO-46 (AFS). The as-obtained C-dots@AFS composite material shows nonlinear optical property, which can be used as saturable absorber (SA) to generate Q-switched ytterbium-doped fiber laser (YDFL). By inserting the C-dots@AFS SA into an YDFL cavity pumped by a 980 nm laser diode, stable passively Q-switched fiber laser can be obtained for a threshold pump power of 220 mW, and 4.5 μs pulses with a repetition rate of 33.51 kHz can be obtained for a pump power of 380 mW. To the best of our knowledge, this is the first demonstration of a C-dots@AFS-based Q-switched fiber laser.

The outer membrane (OM) of Gram-negative bacteria is an evolving antibiotic barrier composed of a glycerophospholipid (GP) inner leaflet and a lipopolysaccharide (LPS) outer leaflet. The two-component regulatory system CrrAB has only recently been reported to confer high-level polymyxin resistance and virulence in Klebsiella pneumoniae. Mutations in crrB have been shown to lead to the modification of the lipid A moiety of LPS through CrrAB activation. However, functions of CrrAB activation in the regulation of other lipids are unclear. Work here demonstrates that CrrAB activation not only stimulates LPS modification but also regulates synthesis of acyl-glycerophosphoglycerols (acyl-PGs), a lipid species with undefined functions and biosynthesis. Among all possible modulators of acyl-PG identified from proteomic data, we found expression of lipid A palmitoyltransferase (PagP) was significantly upregulated in the crrB mutant. Furthermore, comparative lipidomics showed that most of the increasing acyl-PG activated by CrrAB was decreased after pagP knockout with CRISPR-Cas9. These results suggest that PagP also transfers a palmitate chain from GPs to PGs, generating acyl-PGs. Further investigation revealed that PagP mainly regulates the GP contents within the OM, leading to an increased ratio of acyl-PG to PG species and improving OM hydrophobicity, which may contribute to resistance against certain cationic antimicrobial peptides resistance upon LPS modification. Taken together, this work suggests that CrrAB regulates the palmitoylation of PGs and lipid A within the OM through upregulated PagP, which functions together to form an outer membrane barrier critical for bacterial survival.

The phenotype of β-thalassemia underlies multigene interactions, making clinical stratification complicated. An increasing number of genetic modifiers affecting the disease severity have been identified, but are still unable to meet the demand of precision diagnosis. Here, we systematically conducted a comparative plasma proteomic profiling on patients with β-thalassemia and healthy controls. Among 246 dysregulated proteins, 13 core protein signatures with excellent biomarker potential are proposed. The combination of proteome and patients' clinical data revealed patients with codons 41/42 -TTCT mutations have an elevated risk of higher iron burden, dysplasia, and osteoporosis than patients with other genotypes. Notably, 85 proteins correlating to fetal hemoglobin (Hb F) were identified, among which the abundance of 27 proteins may affect the transfusion burden in patients with β-thalassemia. The current study thus provides protein signatures as potential diagnostic biomarkers or therapeutic clues for β-thalassemia.

Sulfur-doped graphene quantum dots (S-GQDs) were synthesized by two facile hydrothermal technologies. The photoluminescence (PL) properties of the GQDs and S-GQDs samples were mainly investigated. Through regulating the content of S powders in S-GQDs synthesizing process, the optimal S-GQDs have a high S/C atomic ratio of 19.53%. The S doping introduce more functional groups on the C sp2 skeleton of S-3 sample and result in the appearance of the strong absorption band in the UV region. In comparison with other reported S-GQDs, the S-GQDs exhibit overwhelming high fluorescence quantum yield (57%) and excitation-independent emission, resulting from the outcome of the doped sulfur atoms. Moreover, the PL intensity of GQDs can be increased by doping it with S and the increasing efficiency depends on the thiophene sulfur content.

Land use change is one of the most important factors affecting the migration of non-point source (NPS) pollution. Watersheds in semi-urbanized areas are sensitive to human activities, especially the change of land use, which leads to significant changes in NPS pollution. In our research, by simulating the continuous dynamic migration path of NPS pollution in a typical small basin (Houxi River Basin) in a semi-urbanized area, a key indicator, namely the land use impact coefficient (LUIC), is proposed to explore the extent of the impact of land use on the export coefficient (EC) of NPS pollution. To reduce ECs, we set three scenarios for optimizing LUICs. The results show that: (1) Compared with the buffer zone in the mainstream of the river (1.16 km2), by optimizing land use/land cover types of areas with high LUIC (0.71 km2), the EC reduced by 0.58%, which is higher than that of reduced by 0.21%; (2) In terms of the sub-watersheds, the closer to the mainstream of the river, the more effective the reduction of EC by optimizing land use/land cover in areas with high LUIC; and (3) Compared with the ECs of areas with high LUIC under different buffer zone widths, the ECs of different LUIC values under a 90-meter buffer zone have a higher decline rate. Meanwhile, it is also necessary to consider the actual situation and reduce the costs of greening by selecting appropriate buffer zone areas. The significance of this research is that the proposed method is conducive to rapidly identifying the key areas of land use affecting the migration of NPS pollution. Through the rational planning of green space, it is possible to reduce ECs and lay a research foundation for proposing targeted land management, regional spatial planning, and strategies for the protection of basin ecological environments.

Nitrogen-enriched graphene was fabricated via a facile strategy. Graphene oxide (GO) nanosheets and graphene oxide quantum dots (GQDs) were used as a structure-directing agent and in situ activating agent, respectively, after photoreduction under NH 3 atmosphere. The combination of photoreduction and NH 3 not only reduced GO and GQD composites (GO/GQDs) within a shorter duration but also doped a high level of nitrogen on the composites (NrGO/GQDs). The nitrogen content of NrGO/GQDs reached as high as 18.86 at% within 5 min of irradiation. Benefiting from the nitrogen-enriched GO/GQDs hybrid structure, GQDs effectively prevent the agglomeration of GO sheets and increased the numbers of ion channels in the material. Meanwhile, the high levels of nitrogen improved electrical conductivity and strengthened the binding energy between GQD and GO sheets. Compared with reduced GO and low nitrogen-doped reduced GO, NrGO/GQD electrodes exhibited better electrochemical characteristics with a high specific capacitance of 344 F g −1 at a current density of 0.25 A g −1 . Moreover, the NrGO/GQD electrodes exhibited 82% capacitance retention after 3000 cycles at a current density of 0.8 A g −1 in 6 M KOH electrolyte. More importantly, the NrGO/GQD electrodes deliver a high energy density of 43 Wh kg −1 at a power density of 417 W kg −1 in 1 M Li 2 SO 4 electrolyte. The nitrogen-doped graphene and corresponding supercapacitor presented in this study are novel materials with potential applications in advanced energy storage systems.

Listeria monocytogenes can form persistent biofilms on food processing surfaces, resulting in cross-contamination of food products, including milk and milk products. Natural glycolipids are a promising intervention to control undesirable microbes due to their antimicrobial activity and low toxicity. This study aimed to determine the antimicrobial activity of glycolipids to control L. monocytogenes biofilms as well as in milk and on Queso Fresco. Application of a natural glycolipid product significantly reduced biofilm-associated L. monocytogenes on both polystyrene and stainless steel at concentrations as low as 45 mg/L. When added to UHT skim milk, a concentration of 1000 mg/L inhibited L. monocytogenes growth through 7 days of storage at 7 °C, and application of 1300 and 1500 mg/L reduced counts to levels below the limit of enumeration at day 21. In contrast, 2000 mg/L were necessary to inhibit growth through 7 days in whole milk. Glycolipid solutions at concentrations ≥10% reduced L. monocytogenes counts on Queso Fresco through 7 days when applied as a dip. Overall, natural glycolipids have potential as a natural alternative for the removal of biofilms and as an antimicrobial to control L. monocytogenes in milk and milk products with short shelf lives.

An all-fiber passively Q-switched ytterbium-doped fiber laser (YDFL) was successfully achieved by using a single-walled carbon nanotube (SWCNT) as a saturable absorber (SA). The SWCNT was fabricated by pyrolyzing tripropylamine in the one-dimensional channel of zeolite single crystal (ZnAPO-5, framework type code: AFI). Zn2+ metal cations were doped to promote the filling density and quality of the SWCNT. Subsequently, by incorporating the SA into an YDFL ring cavity, a stable Q-switched pulse train at 1039.4 nm with a repetition rate of 54.28 kHz was obtained when the pump power elevated to the starting threshold of 245 mW. It proved that this SWCNT@AFI SA can be used as an effective passively Q-switched for operation at 1.0 µm region.

Compact development is one of the most effective solutions for sustainable urbanization under the rapid growth of the urban population. Great efforts have been made to measure urban physical compactness while limited attention has been paid to functional zoning of urban areas. Here, we introduce a novel index, called the functional compactness index (FCI), to quantify urban functional compactness through the integration of geospatial data sources, including Points of Interest (POIs) data, Road Network of OpenStreetMap (RNO) data, and National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) nighttime light data. The FCI does not require the analysis of the grid scale and thus, is technically simpler than conventional compactness index (CI). We examined the effectiveness of FCI on estimating urban compactness under four land use scenarios and in four Chinese cities. The results suggest that: (1) the FCI can comprehensively reflect the intensity of human activity, the differentiation between residential zones and other functional zones, and the mixing degree of different functional zones; (2) the FCI is not affected by the service radius of residential zones; (3) the FCI can reflect the overall and local-scale functional compactness of a city; and (4) the FCI can be used to effectively compare spatial characteristics of functional compactness among different cities. In conclusion, the FCI considers the rationality of urban functional layout, which not only is helpful for urban planning, but also enriches the quantitative methods of urban compactness evaluation.

We report effects of crystallization conditions and gel composition on the hydrothermal synthesis of large zinc-doped AlPO4-15 (ZnAlPO4-15) single crystals by using melamine (MA) as structure directing agent (SDA). By optimizing the following synthesis conditions: amount of MA, molar ratio of ZnO/Al2O3, molar ratio of P2O5/Al2O3, crystallization temperature and duration, the pure phase of ZnAlPO4-15 (size up to 95 μm) with good optical transparency can be obtained at 200 °C with 40 h in the system of Al2O3:1.07MA:0.27ZnO: 1.15P2O5:667H2O. To the best of our knowledge, it is the first report of synthesizing ZnAlPO4-15 by using MA as SDA.

Cheeses made from unpasteurized milk are preferred by many consumers for their complex flavors and aromas among other attributes. However, the potential presence and survival of foodborne pathogens remain a concern. There is, therefore, a need for developing practical and science-based preventive strategies to enhance the safety of these products. The use of commercially produced protective bacterial cultures (PC) can be a practical approach. This study examined the potential of commercially produced PCs when used both individually or in combinations to control Listeria monocytogenes and Salmonella, as well as O157:H7 and non-O157:H7 shiga toxin-producing Escherichia coli (STEC) in growth medium and raw milk. The antimicrobial activity of nine individual PCs and 28 combinations thereof was first determined in growth medium using the cell-free supernatants (CFS). Following the determination of median inhibitory concentrations of individual PCs and their combinations, fractional inhibitory concentration indexes were calculated to classify combinations as synergistic, additive, or antagonistic. Overall, L. monocytogenes was inhibited by lower concentrations of CFS compared to the Gram-negative pathogens. Combinations of PCs with synergistic antimicrobial activity against each pathogen were identified. The efficacy of individual PCs was further determined in raw milk following an incubation time and temperature profile similar to that of cheesemaking and ripening. L. monocytogenes growth was inhibited to counts of ~6 log and ~3 log CFU/mL lower than control when cocultured with PCs of Lactococcus lactis or Lactobacillus plantarum, respectively. Hafnia alvei inhibited the growth of STEC O157, non-O157 STEC, and Salmonella enterica in coculture to ~2 log, ~3.5 log, and ~3 log CFU/mL lower than pathogen controls, respectively. Potential synergistic activity was noted for the combination of Lc. lactis and Pediococcus acidilactici against L. monocytogenes when cocultured in raw milk. This study provides data for the efficacy of commercially produced PCs in controlling the growth of pathogens, suggesting that the use of PCs is a promising strategy for enhancing food safety including the safety of raw milk products such as cheese.

2,5-Dihydroisoxazoles, 4-iodo-2,5-dihydroisoxazoles, and 4-bromo-2,5-dihydroisoxazoles were efficiently constructed from propargylic alcohols and N-tosyl hydroxylamine using ytterbium triflate, iodine and N-bromosuccinimide, respectively. N-sulfonylallenamide is postulated to be the key intermediate for these tandem transformations. Moreover, the resulting 4-iodo-2,5-dihydroisoxazoles could be elaborated by palladium-catalyzed carbonylation to generate 4-methoxycarbonyl-4,5-dihydroisoxazoles.

Electronic structures of Mg 1− x Cr x O ( x = 0 , 0.25, 0.5, 0.75) were investigated based on first-principles calculations using generalized gradient approximation (GGA) and GGA + U . Different magnetic and electronic properties are predicted from the calculated spin-dependent density of states near the Fermi surface. Using the GGA method, Mg 1− x Cr x O is calculated to be ferromagnetic at x = 0.25 and antiferromagnetic at x = 0.5 and 0.75. Alternatively, the ferromagnetic state is stable for all dopant levels when using the GGA + U method. Mg 1− x Cr x O is also half-metallic and its relevant metallic nature is calculated to be highly dependent on the spin state and the dopant levels: the DOS distributions exhibit metallic characteristics for spin-up electrons at x = 0.25 , or for spin-down electrons at x = 0.5 , or even for both at x = 0.75 .