Vancomycin-modified Fe3O4@SiO2@Ag microflowers as effective antimicrobial agents.

Nanomaterials combined with antibiotics exhibit synergistic effects and have gained increasing interest as promising antimicrobial agents. In this study, vancomycin-modified magnetic-based silver microflowers (Van/Fe3O4@SiO2@Ag microflowers) were rationally designed and prepared to achieve strong bactericidal ability, a wide antimicrobial spectrum, and good recyclability. High-performance Fe3O4@SiO2@Ag microflowers served as a multifunction-supporting matrix and exhibited sufficient magnetic response property due to their 200 nm Fe3O4 core. The microflowers also possessed a highly branched flower-like Ag shell that provided a large surface area for effective Ag ion release and bacterial contact. The modified-vancomycin layer was effectively bound to the cell wall of bacteria to increase the permeability of the cell membrane and facilitate the entry of the Ag ions into the bacterium, resulting in cell death. As such, the fabricated Van/Fe3O4@SiO2@Ag microflowers were predicted to be an effective and environment-friendly antibacterial agent. This hypothesis was verified through sterilization of Gram-negative Escherichia coli and Gram-positive methicillin-resistant Staphylococcus aureus, with minimum inhibitory concentrations of 10 and 20 µg mL-1, respectively. The microflowers also showed enhanced effect compared with bare Fe3O4@SiO2@Ag microflowers and free-form vancomycin, confirming the synergistic effects of the combination of the two components. Moreover, the antimicrobial effect was maintained at more than 90% after five cycling assays, indicating the high stability of the product. These findings reveal that Van/Fe3O4@SiO2@Ag microflowers exhibit promising applications in the antibacterial fields.

DNA probe functionalized QCM biosensor based on gold nanoparticle amplification for Bacillus anthracis detection.

The rapid detection of Bacillus anthracis, the causative agent of anthrax disease, has gained much attention since the anthrax spore bioterrorism attacks in the United States in 2001. In this work, a DNA probe functionalized quartz crystal microbalance (QCM) biosensor was developed to detect B. anthracis based on the recognition of its specific DNA sequences, i.e., the 168 bp fragment of the Ba813 gene in chromosomes and the 340 bp fragment of the pag gene in plasmid pXO1. A thiol DNA probe was immobilized onto the QCM gold surface through self-assembly via Au-S bond formation to hybridize with the target ss-DNA sequence obtained by asymmetric PCR. Hybridization between the target DNA and the DNA probe resulted in an increase in mass and a decrease in the resonance frequency of the QCM biosensor. Moreover, to amplify the signal, a thiol-DNA fragment complementary to the other end of the target DNA was functionalized with gold nanoparticles. The results indicate that the DNA probe functionalized QCM biosensor could specifically recognize the target DNA fragment of B. anthracis from that of its closest species, such as Bacillus thuringiensis, and that the limit of detection (LOD) reached 3.5 × 10(2)CFU/ml of B. anthracis vegetative cells just after asymmetric PCR amplification, but without culture enrichment. The DNA probe functionalized QCM biosensor demonstrated stable, pollution-free, real-time sensing, and could find application in the rapid detection of B. anthracis.

Relationship between the grading of periventricular echodensities and periventricular white matter cystic lesions in preterm infants / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To understand the relationship of the grading of periventricular echodensities (PVE) with the morbidity and the occurrence time of periventricular white matter cystic lesions in preterm infants.</p><p><b>METHODS</b>A retrospective, single-centre cohort study of 120 preterm infants with PVE diagnosed by ultrasonography between February 2005 and May 2008 was performed. The infants had a median gestational age of 32 weeks and a median birth weight of 2 230 g.</p><p><b>RESULTS</b>Fifty-two infants (43%) were diagnosed as having PVE I, 42 infants (35%) having PVE II, and 26 infants (22%) having PVE III. The grading of PVE was closely related to birth weight, but not with gestational age. The total morbidity of periventricular white matter cystic lesions was 24% (29/120). The morbidity of the cystic lesions in PVE III patients (65%) was significantly higher than that in PVE II patients (21%) (<0.01). The PVE III patients developed the cystic lesions earlier than the PVE II patients.</p><p><b>CONCLUSIONS</b>The grading of PVE is closely related to the morbidity and the occurrence time of periventricular white matter cystic lesions in preterm infants.</p>

Ultrasonographic findings of intussusception complicated by intestinal necrosis in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>The information on the ultrasonographic features of pediatric intussusception complicated by intestinal necrosis is limited at present. This study aimed to investigate the ultrasonographic findings of this disorder in children in order to provide references for selecting a right means of reduction in clinical practice.</p><p><b>METHODS</b>The ultrasonographic findings of 48 children with intussusception complicated by intestinal necrosis and who underwent operative reduction between 2004 and 2006 were reviewed retrospectively.</p><p><b>RESULTS</b>The type of intussusception was closely correlated to the development of intestinal necrosis and the ileo-ileo-colonic intussusception was the most common one resulting in intestinal necrosis. The bowel wall of the invaginated segment was obviously thickened and the center of the invaginated segment was often accompanied with swollen lymph node and appendix caecalis. The intussusceptional fluidify, the expanding of distal segment accompanied with the thickened bowels wall, and weakening or disappearance of enterokinesia were the appearances of necrosis of most of bowel walls. The secondary intussusception was an important factor resulting in intestinal necrosis, and sound image of primary lesion was found in some patients. Seroperitoneum was a common manifestation in all of infants with intussusception complicated by intestinal necrosis.</p><p><b>CONCLUSIONS</b>There are some obvious sonographic characteristics of intussusception complicated by intestinal necrosis in children. The means of intussusception reduction may be selected according to ultrasonographic characteristics.</p>

Transportation of sulfur mustard (HD) in alkyd coating.

The kinetics of absorption, desorption, and degradation of sulfur mustard (HD) in alkyd coating was experimentally studied, and a one-dimension mass transfer model for the transportation of HD molecule in alkyd coating was established on the experimental data. The obtained results indicated that the persistence of HD molecule could be greatly increased due to the absorption of HD droplets by alkyd coating, and there still occurred the desorption of HD as vapor from coating for more than 3 days even after decontamination of HD droplets onto coating. It was also experimentally shown that the majority of HD both absorbed and desorbed was accomplished at an early stage, less than 10 h, and HD molecule was able to be degraded within the alkyd coating probably through the reactions of hydrolysis and elimination. The diffusion coefficient and degradation rate constant of HD in alkyd coating were determined to be practically around 10(-9) cm2/s and 2.4 x 10(-5) min(-1), respectively.