Preparation and Physicochemical Properties of 10-Hydroxycamptothecin (HCPT) Nanoparticles by Supercritical Antisolvent (SAS) Process

The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO2 and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT

Comparative Study on Electronic Structure and Optical Properties of α-Fe₂O₃, Ag/α-Fe₂O₃ and S/α-Fe₂O₃

The electronic structures and optical properties of pure, Ag-doped and S-doped α-Fe2O3 were studied using density functional theory (DFT). The calculation results show that the structure of α-Fe2O3 crystal changes after Ag and S doping, which leads to the different points of the high symmetry of Ag-doped and S-doped α-Fe2O3 with that of pure α-Fe2O3 in the energy band, as well as different Brillouin paths. In addition, the band gap of α-Fe2O3 becomes smaller after Ag and S doping, and the optical absorption peak shifts slightly toward the short wavelength, with the increased peak strength of S/α-Fe2O3 and the decreased peak strength of Ag/α-Fe2O3. However, the optical absorption in the visible range is enhanced after Ag and S doping compared with that of pure α-Fe2O3 when the wavelength is greater than 380 nm, and the optical absorption of S-doped α-Fe2O3 is stronger than that of Ag-doped α-Fe2O3

Exploring the association between urbanisation and self-rated health of older adults in China: evidence from a national population sample survey

Objectives: this study investigated the association between urbanisation and self-rated health of older adults in China, particularly how different dimensions, rate and level of urbanisation are related to older people’s health. Additionally, it examined the moderating effect of education on the association between each of the four dimensions of urbanisation and older people’s health.Design: the study uses a cross-sectional survey design.Participants: this study analysed 236 030 individuals (aged 60–79 years) nested within 267 prefecture-level cities from 2005 China’s 1% population sample survey.Outcome measures: self-rated health was the outcome variable. Four groups of predictors assessed prefectures’ level and rate of urbanisation: land-use conversion, economic growth, population concentration and health services. Multilevel logistic regression was used to examine the association between self-rated health and the level and rate of urbanisation, after adjusting for individual-level covariates. Multiplicative interactions explored variations by education.Results: the odd of reporting fair or poor health was negatively associated with the level and rate of population concentration (OR 0.93,95%CI 0.87 to 0.99 and 0.74,95%CI 0.59 to 0.93, respectively) and positively associated with the level of health services (OR 1.12, 95% CI 1.06 to 1.19). Land-use conversion, economic growth and health service improvements (the forms of rate of urbanisation) were not significantly associated with self-rated health. Education had a moderating effect on the association between urbanisation and self-rated health.Conclusions: older people living in more densely populated areas and areas undergoing rapid population concentration were less likely to report fair or poor health. This result supports healthy migration and ‘salmon bias’ hypotheses. No urban health penalty was observed for the older adults in China; therefore, the following pathways linking urbanisation to health are unclear: lifestyle changes, environmental pollution and cultivated land reduction

A Novel Preparation Method for Camptothecin (CPT) Loaded Folic Acid Conjugated Dextran Tumor-Targeted Nanoparticles

In this study, folic-dextran-camptothecin (Fa-DEX-CPT) tumor-targeted nanoparticles were produced with a supercritical antisolvent (SAS) technique by using dimethyl sulfoxide (DMSO) as a solvent and carbon dioxide as an antisolvent. A factorial design was used to reveal the effect of various process parameters on the mean particle size (MPS) and morphology of the particles formed. Under the optimum operation conditions, Fa-DEX-CPT nanoparticles with a MPS of 182.21 nm were obtained. Drug encapsulation efficiency and loading efficiency were 62.13% and 36.12%, respectively. It was found that the concentrations of the camptothecin (CPT) and dextran solution had a major influence upon morphology and shape of the final product. In addition, the samples were characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) with the purpose of developing a suitable targeted drug delivery system for cancer chemotherapy

Effect of intestinal microbiota on duck short-beak and dwarf syndrome caused by novel goose parvovirus

ABSTRACT: Short-beak and dwarf syndrome (SBDS) is caused by infection with novel goose parvovirus (NGPV), which leads to intestinal dysbiosis, developmental delay, short beak, lameness, and paralysis in ducks and is the cause of skeletal health problems. NGPV infection can cause intestinal microbial disturbances, but it is still unclear whether the intestinal microbiota affects the pathogenicity of NGPV. Here, the effects of intestinal microbiota on NGPV-induced SBDS in Cherry Valley ducks were assessed by establishing a duck model for gut microflora depletion/reestablishment through antibiotics (ABX) treatment/fecal microbiota transplanted (FMT). By measuring body weight, beak length, beak width and tarsal length, we found that SBDS clinical symptoms were alleviated in ducks treated with ABX, but not in FMT ducks. Next, we conducted a comprehensive analysis of bone metabolism, gut barrier integrity, and inflammation levels using quantitative real-time PCR (qPCR), enzyme linked immunosorbent assay (ELISA), biochemical analysis and histological analysis. The results showed that ABX treatment improved bone quality reduced bone resorption, mitigated tissue lesions, protected intestinal barrier integrity, and inhibited systemic inflammation in NGPV-infected ducks. Moreover, cecal microflora composition and short-chain fatty acids (SCFAs) production were examined by bacterial 16S rRNA sequencing and gas chromatography. The results revealed that ABX treatment mitigated the decreased abundance of Firmicutes and Bacteroidota in NGPV-infected ducks, as well as increased SCFAs production. Furthermore, ABX treatment reduced the mucosa-associated lymphoid tissue lymphoma translocation protein 1 (Malt1) and nuclear factor κB (NF-κB) expression, which are correlated with systemic inflammation in SBDS ducks. These findings suggested that intestinal microflora depletion alleviated NGPV-induced SBDS by maintaining intestinal homeostasis, inhibiting inflammatory response and alleviating bone resorption. These results provide evidence for the pivotal role of intestinal microbiota in the process of SBDS and contribute a theoretical basis for the feasibility of microecological preparation as a method to control SBDS

Differential responses of Lasiopodomys mandarinus and Lasiopodomys brandtii to chronic hypoxia: a cross-species brain transcriptome analysis

Abstract Background Subterranean rodents have evolved many features to adapt to their hypoxic environment. The brain is an organ that is particularly vulnerable to damage caused by exposure to hypoxic conditions. To investigate the mechanisms of adaption to a hypoxic underground environment, we carried out a cross-species brain transcriptome analysis by RNA sequencing and identified genes that are differentially expressed between the subterranean vole Lasiopodomys mandarinus and the closely related above-ground species Lasiopodomys brandtii under chronic hypoxia [10.0% oxygen (O2)] and normoxia (20.9% O2). Results A total of 355 million clean reads were obtained, including 69,611 unigenes in L. mandarinus and 69,360 in L. brandtii. A total of 235 and 92 differentially expressed genes (DEGs) were identified by comparing the hypoxic and control groups of L. mandarinus and L. brandtii, respectively. A Gene Ontology (GO) analysis showed that upregulated DEGs in both species had similar functions in response to hypoxia, whereas downregulated DEGs in L. mandarinus were enriched GO terms related to enzymes involved in aerobic reactions. In the Kyoto Encyclopedia of Genes and Genomes pathway analysis, upregulated DEGs in L. mandarinus were associated with angiogenesis and the increased O2 transport capacity of red blood cells, whereas downregulated DEGs were associated with immune responses. On the other hand, upregulated DEGs in L. brandtii were associated with cell survival, vascular endothelial cell proliferation, and neuroprotection, while downregulated genes were related to the synaptic transmission by neurons. Conclusions L. mandarinus actively adapts its physiological functions to hypoxic conditions, for instance by increasing O2 transport capacity and modulating O2 consumption. In contrast, L. brandtii reacts passively to hypoxia by decreasing overall activity in order to reduce O2 consumption. These results provide insight into hypoxia adaptation mechanisms in subterranean rodents that may be applicable to humans living at high altitudes or operating in other O2-poor environments