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We developed a new scheme for cryogen-free cooling down to sub-3 K temperature range and ultra-low vibration level. An ultra-high-vacuum cryogen-free scanning probe microscope (SPM) system was built based on the new scheme. Instead of mounting a below-decoupled cryocooler directly onto the system, the new design was realized by integrating a Gifford-McMahon cryocooler into a separate liquefying chamber, providing two-stage heat exchangers in a remote way. About 10 L of helium gas inside the gas handling system was cooled, liquefied in the liquefying chamber, and then transferred to a continuous-flow cryostat on the SPM chamber through an ∼2 m flexible helium transfer line. The exhausted helium gas from the continuous-flow cryostat was then returned to the liquefying chamber for reliquefaction. A base temperature of ∼2.84 K at the scanner sample stage and a temperature fluctuation of almost within ±0.1 mK at 4 K were achieved. The cooling curves, tunneling current noise, variable-temperature test, scanning tunneling microscopy and non-contact atomic force microscopy imaging, and first and second derivatives of I(V) spectra are characterized to verify that the performance of our cryogen-free SPM system is comparable to the bath cryostat-based low-temperature SPM system. This remote liquefaction close-cycle scheme shows conveniency to upgrade the existing bath cryostat-based SPM system, upgradeability of realizing even lower temperature down to sub-1 K range, and great compatibility of other physical environments, such as high magnetic field and optical accesses. We believe that the new scheme could also pave a way for other cryogenic applications requiring low temperature but sensitive to vibration. [ABSTRACT FROM AUTHOR]

Monitoring and regulating levels of hydrogen peroxide and oxygen in cells can provide valuable information for cancer diagnosis, treatment, and development. However, it remains a significant challenge. In this study, a new nanocomposite (CaO2-Co3O4@HA) was developed by combining CaO2 nanoparticles and Co3O4 nanopolyhedrons and functionalization with hyaluronic acid (HA). The resulting nanoreactor can dynamically regulate contents of hydrogen peroxide and oxygen in cells. Due to the presence of HA, the synthesized CaO2-Co3O4@HA has good biocompatibility and active targeting ability. The CaO2 nanoparticles produce enough H2O2 in a slightly acidic (pH 6.5) environment, while the Co3O4 nanopolyhedrons with good catalase (CAT) mimic activity can effectively catalyze H2O2 into O2. The CaO2-Co3O4@HA then acted as a cascade nanoreactor for the self-supplying of hydrogen peroxide/oxygen. The process was monitored using H2O2 and O2 fluorescence probes and confirmed by fluorescence spectra and fluorescence confocal microscopy. This study not only verifies that the nanoreactor has a high ability to self-supply H2O2 and catalyze the generation of oxygen via the metal oxides under slightly acidic conditions but also provides a new way to regulate the contents of oxygen and hydrogen peroxide in cells. The tandem nanoreactor may have potential implications for cancer diagnosis and treatment through the regulation of reactive oxygen species in the cellular microenvironment. [ABSTRACT FROM AUTHOR]

Background: Rhodopseudomonas palustris had the effect of adsorbing and removing lead ions. Metabolomics is a comprehensive analysis based on several metabolites or biomarkers. Objective: The paper aimed to investigate the restorative effect and the potential mechanisms of R. palustris in rats with the lead exposure model using 1H-NMR metabolomics. Results: Nine endogenous metabolites from rat plasma and 13 endogenous metabolites from rat urine were identified as potential biomarkers of the symptoms of lead poisoning. The changes of metabolites levels in the plasma included lower levels of valine, acetoacetate, and N-acetyl-glycoprotein and a higher concentration of lactate, acetate, creatine, threonine, glutamine, and asparagine in model group compared with control group. Furthermore, increased citrate, succinate, dimethylamine, pyruvate, acetoacetate, α-oxoglutarate and asparagine, accompanied by decreased LDL/VLDL, taurine, creatinine, glucose and hippurate levels were observed in the model group compared with the control group in the urine. Biochemical parameters and histopathology examination dovetailed well with the metabolomics data. Treatment with R. palustris at a certain degree returned the levels of these metabolites to normal levels. Plasma and urine metabolomic analysis showed changes associated with energy metabolism, amino acids and fatty acid metabolism of lead exposure rats. Conclusion: The effects of removing lead ions of R. palustris in rats with lead exposure were confirmed. This research demonstrated that 1H-NMR-based metabolomics was a promising tool to identify potential biomarkers and unravel protective effect mechanisms of R. palustris in lead poisoning rats. [ABSTRACT FROM AUTHOR]

An intestinal stoma is a surgically formed exteriorisation of the large or small bowel on to the anterior abdomen wall, to enable faeces to be excreted from the body. Patients living with a stoma may encounter physical, psychological, and social barriers and challenges. Stoma self-management education is essential to improving self-care competence, and patients who perceive the benefits of self-management education show a better adjustment to living with a stoma. This literature review explored the effectiveness of patient education interventions in improving the self-care knowledge and skills of patients living with an ostomy. The findings from the nine studies reviewed showed that self-management education approaches are effective in improving patients' self-care. The application of different approaches to ostomy self-management education, such as a transtheoretical model, chronic care model, telehealth and multimedia-based programmes – helped improve patients' self-care ability. The review also found that patients needed at least 3 months to develop the skills and maintain their ability to self-care. In addition, two education sessions provided to patients in hospital pre-discharge appeared sufficient for improving and maintaining self-care abilities. Where patients received education in hospital post-surgery, 2 or 3 sessions over 7 days were found to be sufficient to provide them with stoma care skills. Education sessions based on the transtheoretical model and chronic care model or telehealth helped maintain and reinforce self-care behaviours following discharge. [ABSTRACT FROM AUTHOR]