Elderly tourism management: A bibliometric approach

Elderly tourism constitutes an important sector within the sustainable development of the tourism industry, attracting an increasing body of research focused on market development. This study aims to outline the progression of elderly tourism research within the past five years (2019–2023) and determine prospective research trajectories and opportunities in the subject. Employing CiteSpace visual analysis technology, this investigation constructs knowledge graphs of authors, institutions, and countries from 332 English-language academic articles from the Web of Science and culminates a keyword co-occurrence knowledge graph. Next, cluster and burst analyses revealed the prevailing trends and focal points in elderly tourism research. The results underscore that while many researchers have been drawn to elderly tourism, the collaborative relationships between these scholars remain tenuous, resulting in the relatively disparate study and the absence of a lead author group. China dominates the field, producing a far greater quantity of studies than other nations. Hence, this study encourages different countries, higher education institutions and disciplines to strengthen cooperation in the management and development of elderly tourism, especially paying attention to the importance of elderly tourism services, quality management and technology integration for the sustainable development of elderly tourism

A Combined SERS and MCBJ Study on Molecular Junctions on Silicon Chips

We have developed a combined Surface-enhanced raman spectroscopy (SERS) and mechanically controllable break junction (MCBJ) method to detect and characterize molecular junctions formed by two electrochemically nanofabricated electrodes on silicon chips. The method allows us to obtain vibrational spectra of the molecular junction and perform electron transport measurement on the molecules simultaneously. The preliminary IN characterization and SERS measurement on an asymmetric molecule, OPE-NO(2), and a symmetric molecule, OPE, were conducted. This approach may provide new insights into not only electron transport in molecules, but also the enhancement mechanism in single-molecule SERS

A Companion Cell–Dominant and Developmentally Regulated H3K4 Demethylase Controls Flowering Time in Arabidopsis via the Repression of FLC Expression

Flowering time relies on the integration of intrinsic developmental cues and environmental signals. FLC and its downstream target FT are key players in the floral transition in Arabidopsis. Here, we characterized the expression pattern and function of JMJ18, a novel JmjC domain-containing histone H3K4 demethylase gene in Arabidopsis. JMJ18 was dominantly expressed in companion cells; its temporal expression pattern was negatively and positively correlated with that of FLC and FT, respectively, during vegetative development. Mutations in JMJ18 resulted in a weak late-flowering phenotype, while JMJ18 overexpressors exhibited an obvious early-flowering phenotype. JMJ18 displayed demethylase activity toward H3K4me3 and H3K4me2, and bound FLC chromatin directly. The levels of H3K4me3 and H3K4me2 in chromatins of FLC clade genes and the expression of FLC clade genes were reduced, whereas FT expression was induced and the protein expression of FT increased in JMJ18 overexpressor lines. The early-flowering phenotype caused by the overexpression of JMJ18 was mainly dependent on the functional FT. Our findings suggest that the companion cell–dominant and developmentally regulated JMJ18 binds directly to the FLC locus, reducing the level of H3K4 methylation in FLC chromatin and repressing the expression of FLC, thereby promoting the expression of FT in companion cells to stimulate flowering

Determination of trace Pb(II), Cd(II) and Zn(II) using differential pulse stripping voltammetry without Hg modification

National Natural Scientific Foundation of China [21175112]; Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry, SOA [GCMAC 1204]; Fujian Key Projects of Science and Technology [2011YZ0001-1]In this work, we reported a simultaneous determination approach for Pb(II), Cd(II) and Zn(II) at mu g L-1 concentration levels using differential pulse stripping voltammetry on a bismuth film electrode (BiFE). The BiFE could be prepared in situ when the sample solution contained a suitable amount of Bi(NO)(3), and its analytical performance was evaluated for the simultaneous determination of Pb(II), Cd(II) and Zn(II) in solutions. The determination limits were found to be 0.19 mu g L-1 for Zn(II), and 0.28 mu g L-1 for Pb(II) and Cd(II), with a preconcentration time of 300 s. The BiFE approach was successfully applied to determine Pb(II), Cd(II) and Zn(II) in tea leaf and infusion samples, and the results were in agreement with those obtained using an atomic absorption spectrometry approach. Without Hg usage, the in situ preparation for BiFE supplied a green and acceptability sensitive method for the determination of the heavy metal ions

Fluorescence determination of acrylamide in heat-processed foods

A simple and rapid fluorescence method has been developed for the determination of acrylamide in heat-processed food samples. In the determination, acrylamide is degraded through Hofmann reaction to generate vinyl amine, and pyrrolinone is produced when the vinyl amine reacts with fluorescamine, resulting in a strong fluorescence emission at 480 nm. Hofmann reaction is a key step for the fluorescence determination of acrylaminde, and the reaction conditions are investigated and optimized. Under the optimal conditions, the fluorescence intensity increases with the increase of acrylamide concentrations. The linear range between the fluorescence intensity and the square-root of acrylamide concentrations is from 0.05 μg mL-1 to 20 μg mL-1 with the correlation coefficient R2=0.9935. The detection limit is 0.015 μg mL-1 and the recovery for food samples is from 66.0% to 110.6%. In comparison with Specification of Entry&Exit Inspection and Quarantine Bureau of The Peoples Republic of China (SN/T 2281-2009), the method showed comparable results and demonstrated the accuracy of the method. ? 2014 Elsevier B.V. All rights reserved

Deleting the C84L Gene from the Virulent African Swine Fever Virus SY18 Does Not Affect Its Replication in Porcine Primary Macrophages but Reduces Its Virulence in Swine

(1) Background: African swine fever (ASF) is a highly contagious disease that causes high pig mortality. Due to the absence of vaccines, prevention and control are relatively challenging. The pathogenic African swine fever virus (ASFV) has a complex structure and encodes over 160 proteins, many of which still need to be studied and verified for their functions. In this study, we identified one of the unknown functional genes, C84L. (2) Methods: A gene deficient strain was obtained through homologous recombination and several rounds of purification, and its replication characteristics and virulence were studied through in vitro and in vivo experiments, respectively. (3) Results: Deleting this gene from the wild-type virulent strain SY18 did not affect its replication in porcine primary macrophages but reduced its virulence in pigs. In animal experiments, we injected pigs with a 102 TCID50, 105 TCID50 deletion virus, and a 102 TCID50 wild-type strain SY18 intramuscularly. The control group pigs reached the humane endpoint on the ninth day (0/5) and were euthanized. Two pigs in the 102 TCID50(2/5) deletion virus group survived on the twenty-first day, and one in the 105 TCID50(1/5) deletion virus group survived. On the twenty-first day, the surviving pigs were euthanized, which was the end of the experiment. The necropsies of the survival group and control groups’ necropsies showed that the surviving pigs’ liver, spleen, lungs, kidneys, and submaxillary lymph nodes did not show significant lesions associated with the ASFV. ASFV-specific antibodies were first detected on the seventh day after immunization; (4) Conclusions: This is the first study to complete the replication and virulence functional exploration of the C84L gene of SY18. In this study, C84L gene was preliminarily found not a necessary gene for replication, gene deletion strain SY18ΔC84L has similar growth characteristics to SY18 in porcine primary alveolar macrophages. The C84L gene affects the virulence of the SY18 strain

Lower genomic stability of induced pluripotent stem cells reflects increased non-homologous end joining

Abstract Background Induced pluripotent stem cells (iPSCs) and embryonic stem cells (ESCs) share many common features, including similar morphology, gene expression and in vitro differentiation profiles. However, genomic stability is much lower in iPSCs than in ESCs. In the current study, we examined whether changes in DNA damage repair in iPSCs are responsible for their greater tendency towards mutagenesis. Methods Mouse iPSCs, ESCs and embryonic fibroblasts were exposed to ionizing radiation (4 Gy) to introduce double-strand DNA breaks. At 4 h later, fidelity of DNA damage repair was assessed using whole-genome re-sequencing. We also analyzed genomic stability in mice derived from iPSCs versus ESCs. Results In comparison to ESCs and embryonic fibroblasts, iPSCs had lower DNA damage repair capacity, more somatic mutations and short indels after irradiation. iPSCs showed greater non-homologous end joining DNA repair and less homologous recombination DNA repair. Mice derived from iPSCs had lower DNA damage repair capacity than ESC-derived mice as well as C57 control mice. Conclusions The relatively low genomic stability of iPSCs and their high rate of tumorigenesis in vivo appear to be due, at least in part, to low fidelity of DNA damage repair

Deletion of the L7L-L11L Genes Attenuates ASFV and Induces Protection against Homologous Challenge

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a major epidemic disease endangering the swine industry. Although a number of vaccine candidates have been reported, none are commercially available yet. To explore the effect of unknown genes on the biological characteristics of ASFV and the possibility of a gene-deleted isolate as a vaccine candidate, the strain SY18ΔL7-11, with deletions of L7L–L11L genes from ASFV SY18, was constructed, and its biological properties were analyzed. The results show that deletion of genes L7L-L11L did not affect replication of the virus in vitro. Virulence of SY18△L7-11 was significantly reduced, as 11 of the 12 pigs survived for 28 days after intramuscular inoculation with a low dose (103 TCID50) or a high dose (106 TCID50) of SY18ΔL7-11. All 11 surviving pigs were completely protected against challenge with the parental ASFV SY18 on 28 days postinoculation (dpi). Transient fever and/or irregularly low levels of genomic DNA in the blood were monitored in some pigs after inoculation. No ASF clinical signs or viremia were monitored after challenge. Antibodies to ASFV were induced in all pigs from 14 to 21 days postinoculation. IFN-γ was detected in most of the inoculated pigs, which is usually inhibited in ASFV-infected pigs. Overall, the results demonstrate that SY18ΔL7-11 is a candidate for further constructing safer vaccine(s), with better joint deletions of other gene(s) related to virulence

Deletion of the L7L-L11L Genes Attenuates ASFV and Induces Protection against Homologous Challenge

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a major epidemic disease endangering the swine industry. Although a number of vaccine candidates have been reported, none are commercially available yet. To explore the effect of unknown genes on the biological characteristics of ASFV and the possibility of a gene-deleted isolate as a vaccine candidate, the strain SY18ΔL7-11, with deletions of L7L–L11L genes from ASFV SY18, was constructed, and its biological properties were analyzed. The results show that deletion of genes L7L-L11L did not affect replication of the virus in vitro. Virulence of SY18△L7-11 was significantly reduced, as 11 of the 12 pigs survived for 28 days after intramuscular inoculation with a low dose (103 TCID50) or a high dose (106 TCID50) of SY18ΔL7-11. All 11 surviving pigs were completely protected against challenge with the parental ASFV SY18 on 28 days postinoculation (dpi). Transient fever and/or irregularly low levels of genomic DNA in the blood were monitored in some pigs after inoculation. No ASF clinical signs or viremia were monitored after challenge. Antibodies to ASFV were induced in all pigs from 14 to 21 days postinoculation. IFN-γ was detected in most of the inoculated pigs, which is usually inhibited in ASFV-infected pigs. Overall, the results demonstrate that SY18ΔL7-11 is a candidate for further constructing safer vaccine(s), with better joint deletions of other gene(s) related to virulence

I267L Is Neither the Virulence- Nor the Replication-Related Gene of African Swine Fever Virus and Its Deletant Is an Ideal Fluorescent-Tagged Virulence Strain

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF) which reaches up to 100% case fatality in domestic pigs and wild boar and causes significant economic losses in the swine industry. Lack of knowledge of the function of ASFV genes is a serious impediment to the development of the safe and effective vaccine. Herein, I267L was identified as a relative conserved gene and an early expressed gene. A recombinant virus (SY18ΔI267L) with I267L gene deletion was produced by replacing I267L of the virulent ASFV SY18 with enhanced green fluorescent protein (EGFP) cassette. The replication kinetics of SY18ΔI267L is similar to that of the parental isolate in vitro. Moreover, the doses of 102.0 TCID50 (n = 5) and 105.0 TCID50 (n = 5) SY18ΔI267L caused virulent phenotype, severe clinical signs, viremia, high viral load, and mortality in domestic pigs inoculated intramuscularly as the virulent parental virus strain. Therefore, the deletion of I267L does not affect the replication or the virulence of ASFV. Utilizing the fluorescent-tagged virulence deletant can be easy to gain a visual result in related research such as the inactivation effect of some drugs, disinfectants, extracts, etc. on ASFV