Analysis on Foodborne Pathogen Contamination of Food Samples in Longnan City from 2013 to 2022.

The objective was to determine the prevalence of foodborne pathogens in food in Longnan City, Gansu Province, China. In this research, we conducted tests on baked foods, catering foods, meat, and fruits and vegetables sold in supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens from 2013 to 2022. We analyzed the variety of foodborne pathogens (Salmonella, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and diarrheagenic Escherichia coli) in different sites and food types. Once foodborne pathogens were detected in the sample, it was deemed unqualified. The total detection rates of foodborne pathogens were 1.559%, 3.349%, 1.980%, 1.040%, 3.383%, and 1.303% in food from supermarkets, farmers' markets, restaurants, retail stores, street stalls, and school canteens, respectively. No pathogenic bacteria were detected in baked foods. Salmonella, S. aureus, L. monocytogenes, B. cereus, and diarrheagenic E. coli were detected in catering foods, among which B. cereus had the highest detection rate. Salmonella was the most common pathogenic bacteria detected in meat, while the detection rate of pathogenic bacteria in fruits and vegetables was low, with only one positive sample for diarrheagenic E. coli. Among the six sites, street stalls (3.382%) and farmers' markets (3.349%) had higher detection rates of pathogens. In general, the detection rate of pathogens from 2013 to 2022 was not high, but there were also some hidden dangers. Catering food is vulnerable to pathogen contamination, and street stalls and farmers' markets are the main sites of pollution. According to the above findings, the regulatory authorities should continue to strengthen supervision, guarantee food safety through early warning, and reduce the risk of food contamination.

Boosting sulfides photooxidation by fusing naphthalimide and flavin together.

The efficient and selective photocatalytic conversion of chemicals with visible light and naturally abundant resources has long been desired, but this requires finely designed sensitizers that are capable of converting light into chemical energy for the required energy/electron transfer, bond formation and scission, etc. Inspired by flavin (FL) based enzymes that are capable of initiating many redox reactions in biological systems in visible light, FL and naphthalimide chromophores were fused together as a heavy-atom-free triplet photosensitizer (NI-FL). It is expected that the extended conjugation within NI-FL may benefit absorption in the visible light range, promoting the intersystem crossing to triplet excited states for efficient chemoselective conversions. The absorption and emission maximum of NI-FL are redshifted by ∼40 nm and the absorption is more than doubled (1.53 × 104 M-1 cm-1 at 484 nm) with respect to FL (7.5 × 103 M-1 cm-1 at 439 nm), and a long-lived triplet excited state of intramolecular electron transfer nature was captured (τT = 45.3 µs). The performances of FL and NI-FL in the photooxidation of sulfides in air were also examined. Apart from nearly quantitative selectivity for sulfoxide, NI-FL demonstrates a 0.5-5 fold enhanced performance with respect to FL and the conversion proceeds through radical intermediates formed by electron transfer at excited states with substrates. Mechanistic investigation satisfactorily explained the observed photophysical properties and the dominant role of radical intermediates in the NI-FL catalyzed photooxidation. The findings may help to understand photooxidation sensitized by FL derivatives and benefit the design of novel efficient photosensitizers.

Photophysical properties of N-methyl and N-acetyl substituted alloxazines: a theoretical investigation.

The electronic structure and photophysical properties of a series of N-methyl and N-acetyl substituted alloxazines (AZs) were investigated with extensive density functional theory (DFT) and time-dependent density functional theory (TD-DFT) based calculations. We showed that non-radiative decays from the lowest singlet and triplet excited states of these AZs are dominant over their radiative counterparts. The fast non-radiative decays of the excited AZs can be attributed to the energy consumption (Ereorg) through structural reorganization facilitated by the intrinsic normal modes of the alloxazine framework, as well as their coupling with those of the functional groups. Substitution with functional groups may lead to further perturbation of the electronic structure of the AZ chromophore, which may enhance intersystem crossing with the ππ* states of the AZs. Due to the different bonding of N1 and N3 within the alloxazine framework, substitution may result in AZs with different photophysical properties. Specifically, functionalization at N1 may help in maintaining or even reducing Ereorg and would promote the absorption and radiative decay from the excited AZs. However, the strong coupling of the vibrational modes of acetyl at N3 with the intrinsic normal modes of the alloxazine framework would contribute significantly to Ereorg, and benefit the non-radiative decay of the excited AZs. We expect that the findings would pave the way for rational design of novel AZs with extraordinary photophysical properties.

Waste tire heat treatment to prepare sulfur self-doped char via pyrolysis and K2FeO4-assisted activation methods.

Waste tire was heat-treated to prepare sulfur self-doped chars via pyrolysis and activation processes. Pyrolytic waste tire chars were activated at different temperatures (600 °C, 800 °C, 1000 °C, and 1200 °C) with K2FeO4 additive ratios (mass ratio of K2FeO4 to char) being 0.5, 1, 2, and 3, respectively. The effective activation occurred over 600 °C with K2FeO4 additive ratios over 0.5. The strongest activation occurred at 1000 °C with K2FeO4 additive ratio of 3, and the specific capacitance increased to 129.5 F/g at 1 A/g, which was six times higher than that without K2FeO4. The activation mechanism revealed that higher K2FeO4 additive ratio promoted the transformation of large aromatic ring systems (≥6 rings) to small ones and smaller pores formation. When K2FeO4 additive ratio was less than 2, high ratio not only promoted alkyl-aryl C-C bonds formation, but also inhibited sulfur enrichment with S 2p3/2 (sulphide bridge) converting to S 2p5/2 (sulphone bridge). But when the ratio was further increased, slight decomposition of alkyl-aryl C-C bonds with the promoted conversion of S 2p5/2 to S 2p3/2 was witnessed. Furthermore, higher activation temperature promoted the conversion of aromatic ring systems and alkyl-aryl C-C bonds to form ordered graphitic structures. S 2p3/2 was enriched before 800 °C, but both S 2p3/2 and S 2p5/2 were released at higher temperature. Formation of smaller pores was promoted before 1000 °C, but the char structure was then destroyed to form larger pores when temperature was further increased.

Potential Biochemical Mechanisms of Brain Injury in Diabetes Mellitus.

The goal of this review was to summarize current biochemical mechanisms of and risk factors for diabetic brain injury. We mainly summarized mechanisms published in the past three years and focused on diabetes induced cognitive impairment, diabetes-linked Alzheimer's disease, and diabetic stroke. We think there is a need to conduct further studies with increased sample sizes and prolonged period of follow-ups to clarify the effect of DM on brain dysfunction. Additionally, we also think that enhancing experimental reproducibility using animal models in conjunction with application of advanced devices should be considered when new experiments are designed. It is expected that further investigation of the underlying mechanisms of diabetic cognitive impairment will provide novel insights into therapeutic approaches for ameliorating diabetes-associated injury in the brain.

An efficient polymer coating for highly acid-stable zeolitic imidazolate frameworks based composite sponges.

Zeolitic imidazolate frameworks (ZIFs) possess tremendous potential in various adsorption and catalysis areas for their particular structures. However, the dispersibility and acid stability of ZIFs are important issues hindering their applications. To address these challenges, a transparent polydimethysiloxane (PDMS) coating was constructed to heterogeneously anchor the Cu doped ZIF-67 (Cu/ZIF-67) nanoparticles on melamine sponge surface, achieving a PDMS-coated ZIF three-dimensional composite sponge. Thus PDMS coating could also effectively protect ZIFs from acid damage to prolong the service life of photocatalyticity. It was demonstrated that the composite sponges were able to repeatedly (over 40 cycles) degrade Sudan I dyes with remarkable photocatalytic efficiency (>97%). More importantly, the ion impenetrability of PDMS coating made the ZIFs based composite a longer term catalytic life than unprotected Cu/ZIF-67 under acid condition. Incidentally, due to the introduction of rough ZIFs and hydrophobic PDMS coating, the obtained sponge also exhibits super-hydrophobicity (158.5°), great compressibility and excellent oil/acid water separation performance. We expect that such a polymer coating strategy could act as a novel inspiration for extending the applications and life span of ZIF-based composites.

Thermoresponsive Melamine Sponges with Switchable Wettability by Interface-Initiated Atom Transfer Radical Polymerization for Oil/Water Separation.

Here we have obtained a temperature responsive melamine sponge with a controllable wettability between superhydrophilicity and superhydrophobicity by grafting the octadecyltrichlorosilane and thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) onto the surface of melamine sponge skeletons. The whole process included the silanization in which step the rough surface with low surface energy and the NH2 were provided, and the atom transfer radical polymerization which ensured the successful grafting of PNIPAAm onto the skeleton's surface. The product exhibits a good reversible switch between superhydrophilicity and superhydrophobicity by changing the temperature below or above the lower critical solution temperature (LCST, about 32 °C) of PNIPAAm, and the modified sponge still retains a good responsiveness after undergoing two temperature switches for 20 cycles. Simultaneously, the functionalized sponges could be used to absorb the oil under water at 37 °C, and they released the absorbed oil in various ways under water at 20 °C, showing wide potential applications including oil/water separation.

Application of loop-mediated isothermal amplification for detection of Yersinia enterocolitica in pork meat.

A loop-mediated isothermal amplification (LAMP) method was developed for the detection of Yersinia enterocolitica isolates in both pure bacterial cultures and pork meat. The LAMP primers, which corresponded to the gyrB gene, accurately identified 4 different bioserotypes of Y. enterocolitica. These primers failed to detect Y. pseudotuberculosis, Y. frederiksenii, and 17 non-Yersinia strains. The sensitivity of the LAMP assay for the detection of Y. enterocolitica in pure culture was 65 CFU/mL (31.6 fg of genomic DNA). The LAMP assay was conducted for the detection of Y. enterocolitica strains in 21 pig tonsil samples and 73 pork meat samples obtained from 94 slaughtered pigs belonging to 4 different herds. Y. enterocolitica was found to be present in 4 tonsil samples and none in meat samples. This is the first report in which the LAMP assay was employed for the detection of Y. enterocolitica in food samples.

Development of a sensitive and quantitative assay for spring viremia of carp virus based on real-time RT-PCR.

A one-step real-time reverse transcription-polymerase chain reaction (RT-PCR) using a TaqMan probe to quantitatively detect spring viremia of carp virus (SVCV) is described. In this assay, a pair of primers amplifying an 81-bp DNA fragment and a TaqMan probe was designed targeting the conserved region at the SVCV glycoprotein (G) gene. To avoid the disadvantages arising from plasmids, an extension adding a T7 phage polymerase promoter to the 5' end of the antisense primer was carried out to obtain viral cRNA. Standardized cycle threshold (Ct) values for 10-fold serial dilutions of SVCV cRNA were achieved by real-time RT-PCR and used to create standard curves. A regression line between the mean Ct values and viral template concentrations over a 1:10(7) dilution range with an r(2) value (0.9916) and a slope (-3.36) and the coefficient of variation (intra- or inter-assay is <2% and <4%, respectively) indicated that the assay was highly reproducible. The assay was specific to SVCV and there was no cross-reactivity with other fish viruses (viral hemorrhagic septicemia virus, VHSV; infectious pancreatic necrosis virus, IPNV; grass carp reovirus, GCRV; epizootic haematopoietic necrosis virus, EHNV). The standard curve allows precise absolute quantitation and shows that the detection limit of the assay is 40 copies of the viral RNA. This one-step RT-PCR assay was evaluated using 60 clinical common carp samples collected during the year 2006, indicating such technology offers considerable advantages over conventional RT-PCR methods in current routine use for SVCV surveillance. This is the first report of the development of a one-step TaqMan RT-PCR for SVCV detection.

Development of real-time polymerase chain reaction assay with TaqMan probe for the quantitative detection of infectious hypodermal and hematopoietic necrosis virus from shrimp.

An assay was developed for the detection of infectious hypodermal and hematopoietic necrosis virus (IHHNV) based on real-time quantitative polymerase chain reaction (PCR). A pair of primers and a TaqMan probe were designed that are specific for the recognition of a conservative region in the IHHNV genome. The IHHNV real-time PCR assay had a detection limit of 9 DNA copies, with a dynamic range of detection between 9 x 106 and 9 DNA copies. The primer pairs and probe were specific to IHHNV and did not cross-react with shrimp genomic DNA or other shrimp viruses such as White Spot Syndrome Virus (WSSV), Monodon Baculovirus (MBV), and hepatopancreatic parvovirus (HPV). This assay has a broad application for basic and clinical investigations. For clinical samples, the real-time PCR assay detected all the positive samples screened by conventional PCR, which indicated the sensitivity of the real-time assay. The IHHNV real-time PCR assay with high sensitivity, specificity, wide range of detection ability, and simplicity is particularly useful for screening large numbers of specimens and measuring viral loads to monitor the broodstock.