The emergence of clinically relevant β-lactam-resistant bacteria poses a serious threat to human health and presents a major challenge for medical treatment. How opportunistic pathogenic bacteria ...acquire antibiotic resistance and the prevalence of antibiotic-resistant opportunistic pathogenic bacteria in the environment are still unclear. In this study, we further confirmed that the selective pressure of heavy metals contributes to the increase in ampicillin-resistant opportunistic pathogens in the Xiangjiang River. Four ampicillin-resistant opportunistic pathogenic bacteria (Pseudomonas monteilii, Aeromonas hydrophila, Acinetobacter baumannii, and Staphylococcus epidermidis) were isolated on Luria-Bertani (LB) agar plates and identified by 16S rRNA sequencing. The abundance of these opportunistic pathogenic bacteria significantly increased in the sites downstream of the Xiangjiang River that were heavily influenced by metal mining activities. A microcosm experiment showed that the abundance of β-lactam resistance genes carried by opportunistic pathogenic bacteria in the heavy metal (Cu2+ and Zn2+) treatment group was 2–10 times higher than that in the control. Moreover, heavy metals (Cu2+ and Zn2+) significantly increased the horizontal transfer of plasmids in pathogenic bacteria. Of particular interest is that heavy metals facilitated the horizontal transfer of conjugative plasmids, which may lead to the prevalence of multidrug-resistant pathogenic bacteria in the Xiangjiang River.
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•Ampicillin-resistant pathogenic bacteria were isolated and identified in the Xiangjiang River.•The pathogenic bacteria cover P. monteilii, A. hydrophila, A. baumannii, and S. epidermidis.•The selective pressure of heavy metals contributed to the bloom of the pathogenic bacteria.•Cu2+ and Zn2+ increased the horizontal transfer of plasmids in the pathogenic bacteria.•Heavy metals may ultimately cause the prevalence of multidrug-resistant pathogenic bacteria.
This study provided a reference for the effects of selective stress of heavy metal pollutants on the prevalence of ampicillin-resistant opportunistic pathogenic bacteria.
•A novel Mach–Zehnder Interferometer (MZI) formed by cascading two vase-shaped tapers in a single mode fiber (SMF) is proposed in this work. The vase-shaped taper is fabricated by fusion splicing a ...fiber sphere with a fiber tip under strong arc discharge.•The curvature sensing characteristic of the proposed vase-shaped taper-based MZI is experimentally investigated, displaying that the interference spectrum has a blue shift with the increase of applied curvature. The sensor realizes a large range measurement of curvature from 0.9284m−1 to 4.0470m−1 with sensitivities of −8.41nm/m−1 and −16.72nm/m−1 in the curvature range of 0.9284m−1 to 2.4564m−1 and 2.6025m−1 to 4.0470m−1, respectively. It also shows a low temperature-curvature cross-sensitivity of −0.0016m−1/°C and −0.00082m−1/°C in the two measurement ranges, which are lower than the corresponding curvature resolutions that are 0.0024m−1 and 0.0012m−1.•The proposed sensor exhibits the advantages of low cost, negligible temperature cross-sensitivity, fine curvature sensitivity and large measurement scale.
A novel Mach–Zehnder Interferometer (MZI) formed by cascading two vase-shaped tapers in a single mode fiber (SMF) is proposed in this work. The vase-shaped taper is fabricated by fusion splicing a fiber sphere with a fiber tip by applying strong arc discharge. The curvature sensing characteristic of the proposed vase-shaped taper-based MZI is experimentally investigated, displaying that the interference spectrum has a blue shift with the increase of applied curvature. The sensor realizes a large range measurement of curvature from 0.9284m−1 to 4.0470m−1 with sensitivities of −8.41nm/m−1 and −16.72nm/m−1 in the curvature range of 0.9284m−1 to 2.4564m−1 and 2.6025m−1 to 4.0470m−1, respectively. Its temperature-curvature cross-sensitivities are −0.0021m−1/°C and −0.0011m−1/°C in the two measurement ranges, which are lower than the corresponding curvature resolutions which are 0.0024m−1 and 0.0012m−1. The proposed sensor exhibits the advantages of low cost, negligible temperature cross-sensitivity, fine curvature sensitivity and large measurement scale.
•Femtosecond laser can realize the production of true three-dimensional structure due to its small heat-affected area, high processing accuracy and efficiency.•Femtosecond lasers are used to ...fabricate Fabry-Perot interferometer (FPI), Mach-Zehnder interferometer (MZI), fiber Bragg grating (FBG), the combination structure of FPI-FBG and MZI-FBG.•The manufacturing process, repeatability, size, sensitivity, stability, cross-sensitivity, mechanical stability, etc. are compared with the traditional sensor made without femtosecond laser.•The development trend and future expectations of optical fiber sensor with microstructures fabricated by femtosecond lasers are discussed.
In order to break through the accuracy limits of traditional processing technology and research microscopic phenomena, the sensing structures are fabricated by femtosecond (fs) laser micro-machining technology based on different sensing principles. Fs laser can realize the production of true three-dimensional structure due to its small heat-affected area, high processing accuracy and efficiency, so that it can achieve multi-parameter, high-precision simultaneous measurement on an optical fiber sensor with a smaller size. The application of fs laser increases the flexibility of the sensing structure and improves the key performance indicators of optical fiber sensors. With its excellent performance, the research interest of some scholars is aroused. In this review, the following are studied: firstly, fs lasers are used to fabricate Fabry-Perot interferometer (FPI), Mach-Zehnder interferometer (MZI), fiber Bragg grating (FBG), the combination structures of interferometer and FBG (CI and FBG); secondly, the manufacturing process, repeatability, size, sensitivity, stability, cross-sensitivity, mechanical stability, etc. are compared with the traditional sensor made without fs laser; finally, according to the current development trend of optical fiber sensing devices, the development trend and future expectations of optical fiber sensor with microstructures fabricated by fs lasers are also discussed.
We aim to evaluate the relationship between the use of metformin and the risk of pancreatic cancer in type 2 diabetes patients.
We systematically searched the observational studies on PubMed, Embase, ...Web of Science, Cochrane Library, clinicalrials.gov, and CNKI databases, extracted relevant data, combined the OR value and 95% CI using the random effect model, and conducted a sensitivity analysis, subgroup analysis, and meta-regression to evaluate the size and stability of this relationship.
Twenty-nine studies from twenty-four articles met our inclusion criteria, including more than 2 million subjects. Overall analysis showed that compared with no use of metformin, the use of metformin could reduce the risk of pancreatic cancer in patients with type 2 diabetes (OR = 0.82, 95% CI (0.69, 0.98)). Subgroup analysis showed that compared with the use of hypoglycemic drugs, the use of metformin could reduce the risk of pancreatic cancer in patients with type 2 diabetes (OR = 0.79, 95% CI (0.66, 0.94)). However, compared with no drugs or only diet therapy, metformin users might increase the risk of pancreatic cancer (OR = 2.19, 95% CI (1.08, 4.44)). Sensitivity analysis confirmed the stability of the study, and there was no significant publication bias.
Compared with the no-use of metformin, metformin users with diabetes can reduce the risk of pancreatic cancer. More research is needed to prove it works.
•A new in-line mode Mach–Zehnder interferometer based on photonic crystal fiber coated was designed.•The graphene quantum dots and polyvinyl alcohol film were used as the sensitive materials.•The MZI ...was formed by splicing a section of PCF between two sections of single mode fiber (SMF) with two up-tapers.•The measurement result revealed that different film thickness had different sensitivity and spectrum movement direction.•Meanwhile, the sensor had the advantages of simple structure, small size, high sensitivity and low cost.
In this paper, a new in-line mode Mach–Zehnder interferometer (MZI) based on photonic crystal fiber (PCF) coated with graphene quantum dots (GQDs) and polyvinyl alcohol (PVA) film for relative humidity (RH) sensing was designed. The MZI was formed by splicing a section of PCF between two sections of single mode fiber (SMF) with two up-tapers. The two up-tapers acted as mode splitter/combiner and were made by fusion tapering technique. The Mach–Zehnder interferometer (MZI) incorporated inter modal interference between core mode and cladding modes of the PCF. The refractive index (RI) and volume of GQDs-PVA film will decrease and expansion with the increase of RH, respectively. By measuring the wavelength shift of the interference pattern, RH measurement could be achieved. Before RH measurement, the external RI was tested experimentally to verify that the interference spectrum shifted to right with the increase of refractive index (RI), and the sensitivity was up to 343.7 nm/RIU. In addition, the RH sensing properties with the different thickness of GQDs-PVA film (2.48 μm, 3.72 μm, 4.45 μm, 5.96 μm, 7.42 μm, 8.17 μm) were also investigated experimentally, and the corresponding sensitivity were -0.0901 nm/%RH, −0.0797 nm/%RH, -0.0337 nm/%RH, 0.0586 nm/%RH, 0.0539 nm/%RH, 0.0313 nm/%RH, respectively. The measurement result revealed that different film thickness had different sensitivity and spectrum movement direction. Meanwhile, the sensor had the advantages of simple structure, small size, high sensitivity and low cost. What’s more, the sensor also presents good stability and reversibility of the sensor.
DNA hydroxymethylation and its mediated DNA demethylation are critical for multiple cellular processes, for example, nuclear reprogramming, embryonic development, and many diseases. Here, we ...demonstrate that a vital nutrient ascorbic acid (AA), or vitamin C (Vc), can directly enhance the catalytic activity of Tet dioxygenases for the oxidation of 5-methylcytosine (5mC). As evidenced by changes in intrinsic fluorescence and catalytic activity of Tet2 protein caused by AA and its oxidation-resistant derivatives, we further show that AA can uniquely interact with the C-terminal catalytic domain of Tet enzymes, which probably promotes their folding and/or recycling of the cofactor Fe2+. Other strong reducing chemicals do not have a similar effect. These results suggest that AA also acts as a cofactor of Tet enzymes. In mouse embryonic stem cells, AA significantly increases the levels of all 5mC oxidation products, particularly 5-formylcytosine and 5-carboxylcytosine (by more than an order of magnitude), leading to a global loss of 5mC (∼40%). In cells deleted of the Tet1 and Tet2 genes, AA alters neither 5mC oxidation nor the overall level of 5mC. The AA effects are however restored when Tet2 is re-expressed in the Tet-deficient cells. The enhancing effects of AA on 5mC oxidation and DNA demethylation are also observed in a mouse model deficient in AA synthesis. Our data establish a direct link among AA, Tet, and DNA methylation, thus revealing a role of AA in the regulation of DNA modifications.
•A novel humidometer depended on unsymmetrical U-shaped twisted MFC is reported.•The special MFC sensing structure are formed by two microfiber tapers.•A layer of PVA material with tens of nanometers ...is covered on the coupling region by the "first in the middle and then on both sides" coating method.•The unsymmetrical U-shaped MFC sensing structure possesses a large detection range (18%-95%RH) at the laboratory temperature.
Owing to the integration of microfiber couplers (MFCs), polyvinyl alcohol overlay (PVA) material and U-shaped structure, a novel humidometer depended on unsymmetrical U-shaped twisted MFC is reported in this work. The special MFC sensing structure is formed by two microfiber tapers, which attach together under the action of van der Waals force and electrostatic attractive force, therefore it is convenient to adjust the coupling length according to the design requirements. In addition, a layer of PVA material with tens of nanometers is covered on the coupling region by the coating method "first in the middle and then on both sides". Finally, the U-shaped MFC is fabricated. This sensing structure possesses a large detection range (18%–95%RH) at the laboratory temperature. The demonstrated sensing structure with larger effective coupling length shows that the humidity sensitivity is 100.2 pm/%RH with a very good linearity (R2 = 0.9961). The RH sensitivity is enhanced by ˜2 times compared with that of the sensor with shorter effective coupling length. This sensor also shows other advantages, including high reversibility, repeatability and low temperature cross-sensitivity.
Graphene quantum dots (GQDs), a smart functional nano-sensing material, present excellent thermo-optic properties. Here a novel fiber-optic temperature sensor based on GQDs solution encapsulated in ...hollow core fiber (HCF) is first proposed. GQDs with the small size less than 20 nm are successfully filled in the inner part of HCF by capillarity, and the compact sensing probe is length of 6 mm. The relationships of the photoluminescence (PL) peak, intensity, and full-width at half-maximum of the PL spectra are investigated with temperature changing from 10 °C to 80 °C. The photoluminescence peak wavelength and the self-referenced intensity all present good sensitivities, which are 123.7 pm/°C and - 0.01375/°C, respectively.
Cancer-associated fibroblasts (CAFs) are highly heterogeneous. With the lack of a comprehensive understanding of CAFs' functional distinctions, it remains unclear how cancer treatments could be ...personalized based on CAFs in a patient's tumor. We have established a living biobank of CAFs derived from biopsies of patients' non-small lung cancer (NSCLC) that encompasses a broad molecular spectrum of CAFs in clinical NSCLC. By functionally interrogating CAF heterogeneity using the same therapeutics received by patients, we identify three functional subtypes: (1) robustly protective of cancers and highly expressing HGF and FGF7; (2) moderately protective of cancers and highly expressing FGF7; and (3) those providing minimal protection. These functional differences among CAFs are governed by their intrinsic TGF-β signaling, which suppresses HGF and FGF7 expression. This CAF functional classification correlates with patients' clinical response to targeted therapies and also associates with the tumor immune microenvironment, therefore providing an avenue to guide personalized treatment.
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•A living biobank of CAFs from NSCLC patients recapitulates clinical CAF heterogeneity•Therapeutic profiling of the NSCLC CAFs reveals three distinctive functional subtypes•Subtype I and II CAFs have high HGF and FGF7 expression and protect cancer cells•Subtype III CAFs associate with better clinical response and immune cell migration
Hu et al. identify that cancer-associated fibroblasts (CAFs) derived from non-small cell lung cancer patients are functionally heterogeneous. These functional distinctions directly impact response to clinical anticancer treatment and associate with the tumor immune microenvironment. Thus, CAF functional heterogeneity defines a unique parameter for designing more personalized treatments.
A good electrochemical performance for a multistep electron transfer reaction calls for low thermodynamic energy barrier, fast kinetics, and abundance of surface reactive intermediates. While ...physical and spectral characterizations fail to obtain most of these details because of interference from the electrolyte and dynamic surface structures under reaction conditions, electrochemical measurements instead are able to provide the most direct information. A thermodynamic-kinetic model was developed in our previous work, which showed great capability to extract the adsorption energies of reactive intermediates through the Tafel plot without considering the exact structures of catalysts in the oxygen evolution reaction (OER). In this work, a more adaptive model in combination with probing the methanol oxidation reaction was developed. This approach offers the following advantages: From the aspect of thermodynamics, an experimentally rationalized adsorption profile could be obtained without the requirement to know the scaling factors of reactive intermediates. From the aspect of surface structure, the potential induced change of intermediates’ coverage in the reaction could be described with high sensitivity. From the aspect of kinetics, multiple Tafel slopes in a single Tafel plot could be explained by potential induced variation in intermediates’ coverage and activation energy in the rate-determining step (RDS). A volcano relation between the symmetry factor and adsorption energy was also discerned and discussed, showing the strong correlation between thermodynamics and kinetics. Our model offers a promising analyzing tool by providing essential information on the electrochemical interface and both thermodynamic and kinetic properties of catalysts, which are important for the design of next-generation high-performance catalysts for multistep electrochemical reactions.
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