Child Skeletal Fluorosis from Indoor Burning of Coal in Southwestern China

Objectives. We assess the prevalence and pathogenic stage of skeletal fluorosis among children and adolescents residing in a severe coal-burning endemic fluorosis area of southwest China. Methods. We used a cross-sectional design. A total of 1,616 students aged between 7 and 16 years in Zhijin County, Guizhou, China in late 2004 were selected via a cluster sampling of all 9-year compulsory education schools to complete the study questionnaire. Any student lived in a household that burned coal, used an open-burning stove, or baked foodstuffs over a coal stove was deemed high-risk for skeletal fluorosis. About 23% (370) of students (188 boys, 182 girls) were identified as high-risk and further examined by X-ray. Results. One-third of the 370 high-risk participants were diagnosed with skeletal fluorosis. Overall prevalence of child skeletal fluorosis due to indoor burning of coal was 7.5%. Children aged 12–16 years were significantly more likely to be diagnosed with skeletal fluorosis than children aged 7–11 years (OR = 1.84, 95% CI: 1.17–2.90; P = .0082). Four types of skeletal fluorosis were identified: constrictive (60.7%), raritas (15.6%), mixed (16.4%), and soft (7.4%). Most diagnosed cases (91%) were mild or moderate in severity. In addition, about 97% of 370 high-risk children were identified with dental fluorosis. Dental fluorosis was highly correlated with skeletal fluorosis in this study. Conclusions. Skeletal fluorosis among children may contribute to poor health and reduced productivity when they reach adulthood. Further efforts to reduce fluoride exposure among children in southwestern of China where coal is burned indoors are desperately needed

In Situ and in Vivo Study of Nasal Absorption of Paeonol in Rats

The objective of this work was to study the in situ and in vivo nasal absorption of paeonol. A novel single pass in situ nasal perfusion technique was applied to examine the rate and extent of nasal absorption of paeonol by rats. Various experimental conditions, such as perfusion rate, pH, osmotic pressure and drug concentration, were investigated. The in situ experiments showed that the nasal absorption of paeonol was not dependent on drug concentration, and fitted a first order process. The absorption rate constant, Ka, increased with an increase in perfusion speed. Paeonol was better absorbed in acidic solutions than in neutral or alkaline solutions. The value of Ka was higher in a hypertonic environment than under isotonic or hypotonic conditions. In vivo studies of paeonol absorption were carried out in rats and the pharmacokinetics parameters of intranasal (i.n.) and intragastric (i.g.) administration were compared with intravenous (i.v.) administration. The bioavailabilities of paeonol were 52.37% and 15.81% for i.n. and i.g, respectively, while Tmax values were 3.05 ± 1.46 min and 6.30 ± 0.70 min. MRT (Mean Residence Time) were 23.19 ± 6.46 min, 41.49 ± 2.96 min and 23.09 ± 5.88 min for i.n., i.g. and i.v. methods, respectively. The results demonstrate that paeonol could be absorbed promptly and thoroughly by i.n. administration in rats

Spread of Streptococcus suis Sequence Type 7, China

Streptococcus suis sequence type (ST) 7 has been spreading throughout China. To determine events associated with its emergence, we tested 114 isolates. In all 106 ST7 strains responsible for human outbreaks and sporadic infections, the tetracycline-resistance gene, tetM, was detected on the conjugative transposon Tn916. Horizontal transmission of tetM is suspected

Streptococcus suis Sequence Type 7 Outbreak, Sichuan, China

An outbreak of Streptococcus suis serotype 2 emerged in the summer of 2005 in Sichuan Province, and sporadic infections occurred in 4 additional provinces of China. In total, 99 S. suis strains were isolated and analyzed in this study: 88 isolates from human patients and 11 from diseased pigs. We defined 98 of 99 isolates as pulse type I by using pulsed-field gel electrophoresis analysis of SmaI-digested chromosomal DNA. Furthermore, multilocus sequence typing classified 97 of 98 members of the pulse type I in the same sequence type (ST), ST-7. Isolates of ST-7 were more toxic to peripheral blood mononuclear cells than ST-1 strains. S. suis ST-7, the causative agent, was a single-locus variant of ST-1 with increased virulence. These findings strongly suggest that ST-7 is an emerging, highly virulent S. suis clone that caused the largest S. suis outbreak ever described

Global analysis of epidemic spreading with a general feedback mechanism on complex networks

Abstract This paper aims to investigate the effects of human behavior and contact heterogeneity on the spread of infectious diseases. For this purpose, a network-based SIRS epidemic model with a general feedback mechanism is proposed. In contrast to previous models, we consider the different fear degrees of individuals who have different potential number of contacts with others, when an epidemic prevails. The basic reproductive number that governs the global dynamics of the model is analytically derived. Accordingly, the permanence of the disease and stability conditions of the equilibria are studied in detail. It is shown that the general feedback mechanism cannot change the basic reproductive number, but theoretical and numerical results indicate that it plays an active role in reducing the disease damage. The obtained results generalize and improve some well-known ones

Research on Effective Design Methods of Core Beam of Full Bridge Aeroelastic Model

The trial-and-error method is complex and tedious, but often adapted to determine the cross-section sizes of core beams in the design of reduced-scale models. In this study, two optimization methods, the optimization methods in ANSYS and the genetic algorithm, are investigated to optimize the cross-section sizes of core beams of reduced-scale models, which centers around two targeted moments of inertia and a targeted torsion constant. Due to the difficulty of obtaining an analytical solution of the torsion constant, a series of numerical solutions are proposed. Then, taking a U-shaped cross section as an example, the four geometric sizes of the section are optimized by the ANSYS optimization method and the genetic algorithm, respectively. The results of both methods are in good agreement with the targeted values, but the ANSYS optimization method is prone to fall into the local optimization zone and hence could be easily affected by the initial values. The shortcomings of the ANSYS optimization method can be easily avoided by the genetic algorithm, and it is easier to reach the global optimal solution. Finally, taking a suspension bridge with a main span of 920 m as a prototype, the full-bridge aeroelastic model is designed and the genetic algorithm is used to optimize the cross-section sizes of core beams in the bridge tower and the deck. Natural frequencies identified from the aeroelastic model agree well with the target ones, indicating the structural stiffness, which is provided by the core beams, has been modelled successfully

Studies of Mucosal Irritation and Cellular Uptake Mechanisms of Xingnaojing Nanoemulsion

Xingnaojing (XNJ) injection was used to treat pneumonia and stroke in clinic in China, but with poor patient compliance. Xingnaojing nanoemulsion for intranasal delivery was developed to improve it. This article tried to evaluate the mucosal irritation of Xingnaojing nanoemulsion and investigate cellular uptake mechanism of its encapsulated lipophilic drugs. The toad palate model and rat nasal mucosa model were used to study the nasal ciliotoxicity and nasal mucosal irritation of nanoemulsion to evaluate its safety intranasally. The cellular uptake mechanism was studied by Calu-3 cell model. Coumarin 6 was encapsulated in nanoemulsion and the endocytic pathways were studied by cellular uptake experiments after being treated with different inhibitors. In toad palate model, the cilia movement of Xingnaojing nanoemulsion group last for 467.40 ± 39.02 min, which was obviously longer than deoxycholate group (90.60 ± 15.40 min). Studies on rats showed that the damage caused by nanemulsion is capable of being recovered. Nanoemulsion uptake was reduced obviously when cells were treated with wortmannin, and it also decreased about 13% when the temperature reduced from 37ºC to 4ºC. Mucosal irritation caused by nanoemulsion is low and the damage is recoverable. The cellular uptake of Xingnaojing nanoemulsion is energy-dependent, and macropinocytosis was the most important pathway for cellular uptake

Superhydrophobic Particles Derived from Nature-Inspired Polyphenol Chemistry for Liquid Marble Formation and Oil Spills Treatment

Nature has given us great inspirations to fabricate high-performance materials with extremely exquisite structures. Presently, particles with a superhydrophobic surface are prepared through nature-inspired polyphenol chemistry. Briefly, adhering of a typical polyphenol (tannic acid, widely existed in tea, red wine, chocolate, <i>etc</i>.) is first conducted on titania particles to form a multifunctional coating, which is further in charge of reducing Ag⁺ into Ag nanoparticles/nanoclusters (NPs/NCs) and responsible for grafting 1H,1H,2H,2H-perfluorodecanethiol, thus forming a lotus-leaf-mimic surface structure. The chemical/topological structure and superhydrophobic property of the as-engineered surface are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), water contact angle measurements, and so on. On the basis of the hierarchical, superhydrophobic surface, the particles exhibit a fascinating capability to form liquid marble and show some possibility in the application of oil removal from water. After particles are <i>in situ</i> adhered onto melamine sponges, the acquired particle-functionalized sponge exhibits an absorption capacity of 73–175 times of its own weight for a series of oils/organic solvents and shows superior ease of recyclability, suggesting an impressive capability for treating oil spills

Microneedle-Assisted Percutaneous Delivery of Paeoniflorin-Loaded Ethosomes

Paeoniflorin, the main component of total glucosides of paeony (TGP), shows good therapeutic effects in arthritis, but has low bioavailability when administered orally. Avoiding such a deficiency for topical administration would expand its clinical application. This study aimed to avoid these limitations by using nanotechnology (ethosomes) and a physical approach (microneedles). Paeoniflorin-loaded ethosomal formulation (TGP-E) was optimized and evaluated in terms of entrapment efficiency (EE), particle size (PS), zeta potential (ZP), polydispersity index (PDI) and morphology. TGP-E was prepared by the hot injection method and optimized by single-factor tests and an orthogonal experimental design. The optimized paeoniflorin-loaded ethosomes had EE of 27.82 &#177; 1.56%, PS of 137.9 &#177; 7.57 nm with PDI of 0.120 &#177; 0.005, ZP of &#8722;0.74 &#177; 0.43 mV. Ethosomes showed a nearly spherical shape under the transmission electron microscope (TEM). The optimal microneedle-assisted (MN-assisted) conditions were obtained at a microneedle length of 500 &#956;m, a pressure of 3 N and an action time of 3 min. The cumulative penetration amounts (Qn) of TGP solution transdermal (ST) and MN-assisted TGP solution transdermal (MST) were 24.42 &#177; 8.35 &#956;g/cm2 and 548.11 &#177; 10.49 &#956;g/cm2, respectively. Qn of TGP-E transdermal (PT) and MN-assisted TGP-E transdermal (MPT) were 54.97 &#177; 4.72 &#956;g/cm2 and 307.17 &#177; 26.36 &#956;g/cm2, respectively. These findings indicate that use of ethosomes and microneedles can both enhance the penetration ofpaeoniflorin, but for the water-soluble drug, there is no obvious synergism between nanotechnology and microneedles for enhancing penetration in a transdermal drug delivery system