Effects of two surface acoustic wave sorting chips on particles multi-level sorting.

Particle/cell sorting has great potential in medical diagnosis and chemical analysis. Two kinds of microfluidic sorting chips (sequential sorting chip and direct sorting chip) are designed, which combine hydraulic force and acoustic radiation force to achieve continuous sorting of multiple particles. Firstly, the optimal values of the angle (α) between the interdigital transducer (IDT) and the main channel, the peak-to-peak voltage (Vpp), the main flow velocity (Vmax) and the flow ratio (A) are determined by simulation and experiments, the related optimal parameters were obtained that the α = 15°, Vpp = 25 V, Vmax = 4 mm/s, flow ratio A1 = 0.2, and A2 = 0.5, respectively. Then, the corresponding sorting experiments were carried out using two kinds of sorting chips to sort the polystyrene (PS) particles with diameters of 1 µm, 5 µm, and 10 µm, and the sorting rate and purity of particles were calculated and analyzed. Experimental results show that the two kinds of sorting chips can achieve continuous sorting of multiple particles, and the sorting effect of sequential sorting chip (control flow ratio) is better than that of direct sorting chip. In addition, the sorting chips in our research have the advantages of simple structure, high sorting efficiency, and the ability to sort multiple particles, which can be applied in medical and chemical research fields, such as cell sorting and chemical analysis.

Superparamagnetic-oil-filled nanocapsules of a ternary graft copolymer.

Stearic and oleic acid-coated Fe3O4 nanoparticles were dispersed in decahydronaphthalene (DN). This oil phase was dispersed in water using ternary graft copolymer poly(glycidyl methacrylate)-graft-[polystyrene-ran-(methoxy polyethylene glycol)-ran-poly(2-cinnamoyloxyethyl methacrylate)] or PGMA-g-(PS-r-MPEG-r-PCEMA) to yield capsules. The walls of these capsules were composed of PCEMA chains that were soluble in neither water nor DN, and the DN-soluble PS chains stretched into the droplet phase and the water-soluble MPEG chains extended into the aqueous phase. Structurally stable capsules were prepared by photolyzing the capsules with UV light to cross-link the PCEMA layer. Both the magnetite particles and the magnetite-containing capsules were superparamagnetic. The sizes of the capsules increased as they were loaded with more magnetite nanoparticles, reaching a maximal loading of ~0.5 mg of ligated magnetite nanoparticles per mg of copolymer. But the radii of the capsules were always <100 nm. Thus, a novel nanomaterial--superparamagnetic-oil-filled polymer nanocapsules--was prepared. The more heavily loaded capsules were readily captured by a magnet and could be redispersed via shaking. Although the cross-linked capsules survived this capturing and redispersing treatment many times, the un-cross-linked capsules ruptured after four cycles. These results suggest the potential to tailor-make capsules with tunable wall stability for magnetically controlled release applications.

pH-responsive nanoemulsions for controlled drug release.

Three ternary graft copolymers bearing polystyrene (PS), poly(ethylene glycol) methyl ether (MPEG), and poly(acrylic acid) (PAA) side chains were synthesized and characterized. At pH = 7.4, these copolymers stabilized doxorubicin (DOX)-containing benzyl benzoate (BBZ) nanoemulsion droplets in water and formed a compact polymer layer to inhibit DOX release. Upon lowering the solution pH to 5.0, the AA groups dissociated less and became less soluble. Moreover, the neutralized AA groups formed presumably H-bonded complexes with the EG units, reducing the solubility of the EG units. This dual action drastically shifted the hydrophilic and hydrophobic balance of the copolymer and caused the original stabilizing polymer layer to rupture and the nanoemulsion droplets to aggregate, releasing DOX. The rate and extent of DOX release could be increased by matching the numbers of PAA and MPEG chains per graft copolymer. In addition, these nanoemulsions were not toxic and entered human carcinoma cells, releasing DOX there. Thus, these nanoemulsions have potential as drug delivery vehicles.

Bismuth-Decorated Beta Zeolites Catalysts for Highly Selective Catalytic Oxidation of Cellulose to Biomass-Derived Glycolic Acid.

Catalytic conversion of cellulose to liquid fuel and highly valuable platform chemicals remains a critical and challenging process. Here, bismuth-decorated ß zeolite catalysts (Bi/ß) were exploited for highly efficient hydrolysis and selective oxidation of cellulose to biomass-derived glycolic acid in an O2 atmosphere, which exhibited an exceptionally catalytic activity and high selectivity as well as excellent reusability. It was interestingly found that as high as 75.6% yield of glycolic acid over 2.3 wt% Bi/ß was achieved from cellulose at 180 °C for 16 h, which was superior to previously reported catalysts. Experimental results combined with characterization revealed that the synergetic effect between oxidation active sites from Bi species and surface acidity on H-ß together with appropriate total surface acidity significantly facilitated the chemoselectivity towards the production of glycolic acid in the direct, one-pot conversion of cellulose. This study will shed light on rationally designing Bi-based heterogeneous catalysts for sustainably generating glycolic acid from renewable biomass resources in the future.

The spatial-temporal distribution and etiological characteristics of hand-foot-and-mouth disease before and after EV­A71 vaccination in Kunming, China, 2017-2020.

After vaccination with enterovirus 71 (EV-A71), the prevalence of hand-foot-and-mouth disease (HFMD) remained high, and the spatial-temporal distribution of enteroviruses changed. Therefore, it is essential to define the temporal features, spatial distributions, and epidemiological and etiological characteristics of HFMD in Kunming. Between 2017 and 2020, a total of 36,540 children were diagnosed with HFMD in Kunming, including 32,754 children with enterovirus-positive clinical samples. Demographic, geographical, epidemiological and etiological data of the cases were acquired and analyzed. Other enteroviruses replaced EV-A71, and the incidence of EV-A71 decreased dramatically, whereas coxsackievirus A6 (CV-A6) and coxsackievirus A16 (CV-A16) had substantial outbreaks in 2018 and 2019, respectively. The major and minor peaks all extended for 2-4 months compared to before vaccination with the EV-A71 vaccine. From 2019 to 2020, CV-A6, as the predominant serotype, showed only a single peak. Although a high incidence of HFMD was observed in Guandu, Chenggong and Xishan, the annual incidence of different enterovirus serotypes was different in different regions. In 2017, other enteroviruses were most prevalent in Shilin. In 2018, CV-A16 and CV-A6 were most prevalent in Luquan and Shilin, respectively. In 2019, CV-A16 was most prevalent in Jinning. In 2020, CV-A6 and coxsackievirus A10 (CV-A10) were most prevalent in Luquan and Shilin, respectively. Meanwhile, the epidemic cycle of CV-A6 and CV-A16 was only 1 year, and CV-A10 and other enteroviruses were potential risk pathogens. The spatial and temporal distribution of HFMD varies at different scales, and the incidence of HFMD associated with different pathogens has obvious regional differences and seasonal trends. Therefore, research on multivalent combined vaccines is urgently needed, and proper preventive and protective measures could effectively control the incidence of HFMD-like diseases.

Water-dispersible superparamagnetic microspheres adorned with two types of surface chains.

Water-dispersible superparamagnetic polymer/γ-Fe(2)O(3) composite microspheres adorned with two types of surface polymer chains are prepared and characterized. To prepare these spheres, we first synthesize uniform γ-Fe(2)O(3) nanoparticles that are covered by poly(2-cinnamoyloxyethyl methacrylate)-block-poly(acrylic acid) (PCEMA-b-PAA). These nanoparticles are then mixed with a PCEMA homopolymer in CHCl(3) to form an oil phase. The oil phase is dispersed into water under vigorous stirring with the help of two diblock copolymer surfactants, PGMA-b-PCEMA and PSGMA-b-PCEMA. Here PGMA and PSGMA denote poly(glyceryl monomethacrylate) and succinated PGMA, respectively. Solid microspheres with cores composed of PCEMA and PCEMA-b-PAA-covered γ-Fe(2)O(3) nanoparticles are obtained after CHCl(3) evaporation and PCEMA photo-cross-linking. Under certain conditions, the coronal PGMA and PSGMA chains become segregated, thus producing surface bumps, ridges, and valleys. The PSGMA chains preferentially cover the protruding regions. The PSGMA carboxyl groups are used to immobilize bovine serum albumin (BSA). The immobilized BSA retains its activity and binds with anti-BSA. These spheres should be useful in immunoassays.

Study on the Mechanism of Targeted Poly(lactic-coglycolic acid) Nano-Delivery Carriers in the Treatment of Hemangiomas.

Hemangiomas, also called infantile hemangiomas (IH), are the most common congenital benign vascular tumors in infants and young children. At present, there are many treatment methods for proliferative hemangiomas, which have different effects and lack predictability. Propranolol has gradually replaced glucocorticoids as the first-line treatment for infants and young children with hemangiomas. However, premature discontinuation is prone to relapse, and the efficacy and safety of medication need to be further studied and determined. The exact pathogenesis of hemangiomas is still unclear. Therefore, in this study, poly(lactic-co-glycolic acid) (PLGA) nanoparticles were used as drug delivery carriers, propranolol was encapsulated, and PLGA-propranolol (PLGA-PP) nanodelivery preparations were prepared and targeted. Anisotropy and pharmacokinetics were preliminary studied. At the same time, after the treatment of HemECs cells with PLGA-PP in gradient concentration in vitro, CCK-8 method was used to detect the cell proliferation, and Anyixin-V/PI double staining method was used to detect the apoptosis rate of cells. The effect of PLGA-PP nano-delivery vector on hemangioma was studied by western blot method to detect the expression level of Id-1 protein in HemECs. The results showed that after PLGA-PP treated HemECs for 24 h, PLGA-PP significantly inhibited HeECs proliferation and promoted their apoptosis, and the intracellular Id-1 protein expression was also reduced. Therefore, this study believes that the mechanism of PLGA-PP nano-targeted delivery preparations in the treatment of hemangiomas is achieved by down-regulating the Id-1 gene, thereby inhibiting the colonization of HemECs and promoting its apoptosis effect.

[Clinical results of ultrasound biometry in silicone oil-filled eye].

OBJECTIVE: To evaluate a method of ultrasound biometry in silicone oil-filled eye and its clinical results. METHODS: This was a series case study. According to the principle of measuring a distance with ultrasound, we compared the measured distance between a space filed with balanced salt solution and silicone oil at same height, to calculate a conversion factor (0.674) between them. A formula for corrective axial length in silicone oil-filled eye was established. The formula = ab + 0.674 x bc (a, b and c standing for the apex of the cornea, the posterior pole of the lens or the center of the capsular membrane and the anterior surface of the macular, respectively). The axial lengths of 150 silicone oil-filled eyes in 150 cases were then measured before and after silicone oil removal with Vivid 7 Dimension ultrasound. According to the axial length, they were divided into two groups, namely group 1 (the length < 25 mm) and group 2 (the length > or = 25 mm). In 76/150 eyes, before combined silicone oil removal and intraocular lens (IOL) implantation, the SRKT formula was used for intraocular lens calculation; the post-operative actual refraction was compared with the pre-operative predicted refraction and statistics analysis was made. RESULTS: The retinal condition of 150 silicone oil-filled eyes in 150 cases after 3 months' follow-up was stable after surgery. The results of the biometry were as follows. In the first group, the mean corrective axial lengths of 111 silicone oil-filled eyes before silicone oil removal was (22.77 +/- 1.00) mm (ranging from 21.10 to 24.90 mm); the mean axial lengths after silicone oil removal was (22.76 +/- 0.99) mm (ranging from 21.00 to 24.70 mm). The difference between them was not statistically significant (t = 0.518, P > 0.05). The vitreous cavity depth before and after silicone oil removal was (26.57 +/- 2.14) mm and (17.90 +/- 1.38) mm, respectively. The ratio of the latter to the former was 0.673 78. In the second group, the mean corrective axial lengths of 39 silicone oil-filled eyes before silicone oil removal was (26.52 +/- 1.31) mm (ranging from 25.00 to 30.58 mm); the mean axial lengths after silicone oil removal was (26.53 +/- 1.29) mm (ranging from 25.00 to 30.59 mm). The difference between them was not statistically significant (t = 0.109, P > 0.05). The vitreous cavity depth before and after silicone oil removal was (32.01 +/- 2.90) mm and (21.57 +/- 2.04) mm, respectively. The ratio of the latter to the former was 0.673 95. In 76 eyes with IOL, the post-operative actual refraction after at least 3 months follow-up was compared with the pre-operative predicted refraction (-1.50 DS) in both groups. The differences between them were not statistically significant (t(1) = 0.253, P(1) > 0.05; t(2) = 0.209, P(2) > 0.05) in each group. CONCLUSION: Ultrasound biometry in silicone oil-filled eye is accurate and simple, and has good results in clinical measurement.

A biodegradable antibiotic-eluting PLGA nanofiber-loaded deproteinized bone for treatment of infected rabbit bone defects.

We fabricated a biodegradable antibiotic-eluting poly(d,l)-lactide-co-glycolide nanofiber-loaded deproteinized bone (ANDB) scaffold that provided sustained delivery of vancomycin to repair methicillin-resistant Staphylococcus aureus bone defects. To fabricate the biodegradable ANDB, poly(d,l)-lactide-co-glycolide and vancomycin were first dissolved in 1,1,1,3,3,3-hexafluoro-2-propano. The solution was then electrospun to produce biodegradable antibiotic-eluting membranes that were deposited on the surface of bovine deproteinized cancellous bone. We used scanning electron microscopy to determine the properties of the scaffold. Both elution and high-performance liquid chromatography assays were used to evaluate the in vitro vancomycin release rate from the ANDB scaffold. Three types of scaffolds were co-cultured with bacteria to confirm the in vitro antibacterial activity. The infected bone defect rabbit model was induced by injecting 10(7) colony forming units of a methicillin-resistant Staphylococcus aureus strain into the radial defect of rabbits. Animals were then separated into treatment groups and implanted according to the following scheme: ANDB scaffold in group A, poly(d,l)-lactide-co-glycolide nanofiber-loaded deproteinized bone (NDB) scaffold with intravenous (i.v.) vancomycin in group B, and NDB scaffold alone in group C. Treatment efficacy was evaluated after eight weeks using radiological, microbiological, and histological examinations. In vitro results revealed that biodegradable ANDB scaffolds released concentrations of vancomycin that were greater than the minimum inhibitory concentration for more than four weeks. Bacterial inhibition tests also confirmed antibacterial efficacy lasted for approximately four weeks. Radiological and histological scores obtained in vivo revealed significant differences between groups A, B and C. Importantly, group A had significantly lower bacterial load and better bone regeneration when compared to either group B or C. Collectively, these results show that our fabricated ANDB scaffolds possess: (1) effective bactericidal activity against methicillin-resistant Staphylococcus aureus, (2) the ability to promote site-specific bone regeneration, and (3) the potential for use in the treatment of infected bone defects.

Tunable ultrathin membranes with nonvolatile pore shape memory.

The concept of a responsive nanoporous thin-film gel membranes whose pores could be tuned to a desired size by a specific "molecular signal" and whose pore geometry becomes "memorized" by the gel is reported. The ∼100 nm thick membranes were prepared by dip-coating from a solution mixture of a random copolymer comprising responsive and photo-cross-linkable units and monodisperse latex nanoparticles used as a sacrificial colloidal template. After stabilization of the films by photo-cross-linking the latex template was removed, yielding nanoporous structures with a narrow pore size distribution and a high porosity. The thin-film membranes could be transferred onto porous supports to serve as tunable size-selective barriers in various colloids separation applications. The pore dimensions and hence the membrane's colloidal-particle-size cutoff were reversibly regulated by swelling-shrinking of the polymer network with a specially selected low-molar-mass compound. The attained pore shape was "memorized" in aqueous media and "erased" by treatment in special solvents reverting the membrane to the original state.

[Identification and characterization of enterovirus 71 isolated in Yunnan province].

OBJECTIVE: Identification and characterization of eight enterovirus 71 samples isolated from Yunnan province. METHODS: Collecting specimens from cases of Hand, Foot and Mouth Disease (HFMD), samples were identificated by RT-PCR, isolated the virus with cells. The isolating virus passaged in vero cells, and the vpl genes sequencing. Immunization the mice with the virus, neutralization test and cross-protection test were conducted with those antisera. RESULT: All samples were identified as EV71, and eight strains had cytopathic effect (CPE) in vero cells, some antisera titers were more than 1:10,000. CONCLUSION: Eight strains of the virus grow well in vero cell, antiserum showed protection against EV71 A and C4 genotype.

[Genetic characteristics of EV71 in Yunnan Province from 2009 to 2010].

In order to learn about the genetic characteristic of human enterovirus type71 (HEV71) isolated from cases of Hand, Foot and Mouth Disease (HFMD) in Yunnan Province from 2009 to 2010. 50 isolates form HFMD cases were performed entire VP1 coding region amplification by reverse transcription-polymerase chain reaction and sequencing the nucleotide sequences; then the phylogenetic tree was constructed. The complete nucleotide sequences of region VP1 of the 50 strains were all 891nt length coding 297 amino acids. The result of molecular identification of the 50 strains is HEV71. Phylogenetic analysis indicated that 48 EV71 isolates belonged to subgenotype C4a and 2 EV71 isolates belonged to genotype A. From 2009 to 2010, the pathogen of HFMD cases were EV71 strains in Yunnan province, which were co-evolved with isolates from other provinces in mainland of China. There was no significant difference found in the whole sequence of VP1 gene of the strains isolated from different regions or under different diseases occurred, but the spread of genetype A appared in Yunnan Province in 2009.

Coating and structural locking of dipolar chains of cobalt nanoparticles.

Above a critical size, Co nanoparticles aggregate because of magnetic dipole-dipole interaction into chains. Reported in this paper is the coating of such chains by an AB diblock copolymer in a block-selective solvent for the A block. Also reported is the cross-linking of the deposited or anchored B block of the diblock copolymer to lock in the coating and thus the dipolar chain structure. The Co nanoparticles used were prepared from the high-temperature decomposition of Co(2)(CO)(8) using poly(2-cinnamoyloxyethyl methacrylate)-block-poly(acrylic acid) or PCEMA-b-PAA as surfactant. To coat the dipolar chains, the particles and diblock copolymer poly(tert-butyl acrylate)-block-poly(2-cinnamoyloxyethyl methacrylate), PtBA-b-PCEMA, were dispersed in a good solvent for PCEMA and PtBA. Methanol, a precipitant for PCEMA and a good solvent for PtBA, was then added. This induced the collapsing of the PCEMA blocks and the deposition of the PCEMA block of PtBA-b-PCEMA onto the surface of PCEMA-b-PAA-coated Co nanoparticle chains. The dipolar chains remained colloidally stable in solution for steric stabilization provided by PtBA. The coating was cured by photocrosslinking the PCEMA layer. Such "permanent" and solvent-dispersible Co dipolar chains are novel and may have interesting applications.

[Magnetic resonance imaging of the upper airway structure of children with sleep disordered breathing].

OBJECTIVE: To investigate the upper airway structure of sleep-disordered breathing children. METHODS: Seventy three children with obstructive sleep apnea hypopnea syndrome (OSAHS), 53 children with primary snoring (PS) and 40 control subjects underwent pharyngeal magnetic resonance imaging (MRI). Upper airway structure images were analyzed and measured. RESULTS: The cross-section area of the nasopharyngeal and palatopharyngeal airway in subjects with OSAHS and PS are smaller (P < 0.01) than that of the control group. The cross section area of OSAHS patients are smaller than that of PS subjects (P < 0.01). The above parameter of oropharyngeal airway in OSAHS patients is smaller than that of control group (P < 0.01), but no statistic difference compared with that of PS subjects. The cross-section area and length of the adenoid in OSAHS group are bigger and longer than that of PS group (P < 0.01) and bilateral tonsils are larger (P < 0.01); in OSAHS patients the cross-section area of the soft palate is larger and the length of the soft palate is longer (P < 0.01) than that of PS group, while this parameter of PS group is similar to that of the control group. And the maximum width of the soft palate, the cross-section area of bilateral fat pad, bilateral pterygoid and tongue are similar among OSAHS, PS and the control group. The skeletal measurement: the length of H-C2C3 in subjects with OSAHS is longer (P < 0.01); The angle(alpha) in OSAHS patients is smaller (P < 0.01) than that of other 2 groups. The angle (beta), the cross-section area of the mandible, the spine-clivus oblique, the length of the hard palate and the distance of the mandible are similar among the three groups. CONCLUSIONS: In children with OSAHS or PS, the upper airway is restricted by both the adenoid and tonsils; however, the soft palate is also larger in OSAHS, adding further restriction. Otherwise, downward movement of the hyoid bone and decreasing of the angle (alpha) in OSAHS influence laryngopharynx airway. MRI is of clinical significance for evaluating OSAHS children's upper airway.

Preparation of magnetic microspheres from water-in-oil emulsion stabilized by block copolymer dispersant.

A new method for the preparation of magnetic microspheres is reported. The preparation involved first the dispersion of an aqueous phase, containing magnetite nanoparticles and a water-soluble homopolymer, into droplets in an organic medium using an amphiphilic block copolymer as the dispersant. This was followed by water distillation at a raised temperature from the aqueous droplets to yield polymer/magnetite particles. The structure of the particles was then locked in by a reagent being added to cross-link the water-soluble copolymer block and homopolymer. Since the hydrophobic block of the copolymer consisted of a protected polyester, the removal of the protective moieties from the coronal chains yielded poly(acrylic acid) or other functional polymers to render water dispersibility to the spheres and to enable biomolecule immobilization.

Water-soluble fluorescent diblock nanospheres.

The hydroxyl groups of poly(tert-butyl acrylate)-block-poly(2-hydroxyethyl methacrylate) or PtBA-b-PHEMA were reacted with succinic anhydride to introduce some carboxyl groups into the PHEMA block. Such carboxyl groups were then reacted with Texas-red cadverine (TX-NH(2)) to incorporate dye molecules. The TX-bearing diblocks formed probably spherical micelles in block-selective solvent DMF/toluene containing 2% DMF. "Permanent" micelles or nanospheres were prepared after cross-linking the TX-bearing PHEMA core block. Such nanospheres were made water soluble by cleaving the tert-butyl groups from the PtBA coronas. Water-soluble nanospheres with high TX numbers and fluorescence quantum yields may find applications in fluorescence in situ hybridization assays.

Thin films of block copolymer blends for enhanced performance of acoustic wave-based chemical sensors.

The performance of quartz crystal oscillator-based volatile organic compound (VOC) sensors has been enhanced by using coatings made from poly(styrene-block-ethylene-co-butylene-block-styrene) block copolymers blended with resins and homopolymers. Enhanced performance is characterized by a wider operational temperature range (-10 to +50 degrees C) over which the sensors displayed, concurrently, an analyte sensitivity of >0.2 Hz/ppm toluene, minimal energy loss (resistance <120 ohms), and response times of <20 min (time required to reach 90% of full response). Atomic force microscopy images are consistent with a process in which the additive associates with the polystyrene portions of the microphase-separated block copolymer. This association reinforces the rigidity of the polystyrene network while allowing the rapid uptake of VOCs by the softer polyethylene/butylene phase.