OBJECTIVE: In order to find whether there is the correlation between the non-oil particle filtration efficiency(PFE) and the bacterial filtration efficiency(BFE) of medical surgical masks. METHODS: Non-oil particle filtration efficiency and bacterial filtration efficiency were compared and analyzed through the test data of medical surgical masks from 2012 to 2018. RESULTS: When the non-oil particle filtration efficiency of medical surgical mask is over 80%, the bacterial filtration efficiency can reach 95%. CONCLUSIONS In order to reach the requirement of 95% bacterial filtration efficiency, surgical medical mask must improve the limit of non-oil particle filtration efficiency. The results of data analysis can provide reference for emergency inspection and filter material rapid inspection, and also provide reference for the revision of YY 0469 standard.
Filtration ; Masks ; Particle Size

BACKGROUND: Shipbuilding involves intensive welding activities, and welders are exposed to a variety of metal fumes, including manganese, that may be associated with neurological impairments. This study aimed to characterize total and size-fractionated manganese exposure resulting from welding operations in shipbuilding work areas. METHODS: In this study, we characterized manganese-containing particulates with an emphasis on total mass (n = 86, closed-face 37-mm cassette samplers) and particle size-selective mass concentrations (n = 86, 8-stage cascade impactor samplers), particle size distributions, and a comparison of exposure levels determined using personal cassette and impactor samplers. RESULTS: Our results suggest that 67.4% of all samples were above the current American Conference of Governmental Industrial Hygienists manganese threshold limit value of 100 μg/m3 as inhalable mass. Furthermore, most of the particles containing manganese in the welding process were of the size of respirable particulates, and 90.7% of all samples exceeded the American Conference of Governmental Industrial Hygienists threshold limit value of 20 μg/m3 for respirable manganese. CONCLUSION: The concentrations measured with the two sampler types (cassette: total mass; impactor: inhalable mass) were significantly correlated (r = 0.964, p < 0.001), but the total concentration obtained using cassette samplers was lower than the inhalable concentration of impactor samplers.
Humans ; Manganese* ; Particle Size ; Welding

The purpose of this study were to investigate the chemical composition, mean particle size, linear thermal expansion coefficient and metal-bonding strength of the regular opaque powder and core powder. In this study, 4 types of ceramic powders, namely Duceram Jacket Opaque powder, Duceram Opaque powder, Vita Hi-Ceram powder, Vita VMK Paint On-88 powder were used. Chemical composition was evaluated by EDS(Energy Dispersive X-ray Spectrophotometer, Oxford QX-2000, England), particle size was measured by MALVERN Instruments(MALVERN Instruments SB. OC., U.S.A.) ad linear thermal expansion coefficient was measured by dilatometer(Motoyama, Japan). Bond strength was measured by the Universal tsting machine(Istron Co., Ltd., U.S.A.). The Results were as follows : 1. Through recognition of the relative difference in chemical composition between the core powder and the regular opaque powder, the difference in the proportion of Al2O3 in each type of material is demonstrated ; Duceram Jaket Opaque powder : 30.16%, Duceram Opaque powder : 16.60%, Vita Hi-Ceram : 63.64%, Vita VMK Paint-On 88 : 16.16%. 2. There was no significant difference in the proportion of metal-bonding materials between the core powder and the regular opaque powder. 3. In the regular opaque powder, alkaline materials were incoporated in order to increase the coefficient of thermal expansion. 4. In the particle size analysis, there was no significant difference in mean particle size or in the particle size distribution between the core powder and the regular opaque powder. 5. In the thermal expansion test for temperature range of 25~600degrees C, the regular opaque powder had higher coefficient of thermal expansion than that of core powder. 6. In the 4 point flexural bending test, there was no statistically significant difference in the mean bond strength between the core powder and the opaque powder among the Duceram products.
Ceramics ; Paint ; Particle Size ; Powders

This study was mainly based on the compatibility of Puerariae Lobatae Radix and Chuanxiong Rhizoma to prepare submicron emulsion and evaluated its physical and pharmaceutical properties. Firstly, pseudo-ternary phase diagrams were drawn by dripping method which took Chuanxiong oil as the oil phase and the area of microemulsion region as the index. On this basis, suitable emulsifier and co-emulsifier were screened for the preparation of Chuanxiong oil submicron emulsion. Then, the formula realizing the largest oil loading was selected. Finally, puerarin substituted part of emulsifier and co-emulsifier to lower their content, so as to form puerarin-Chuanxiong oil submicron emulsion featuring the combination of medicine and adjuvant. Its particle size, zeta potential, centrifugal stability and storage stability were determined, and the in vitro drug release behavior was investigated by dialysis bag method, based on which the quality of the as-prepared submicron emulsion was evaluated comprehensively. The proposed method was proved feasible for the preparation of Chuanxiong oil submicron emulsion, which adopted polyoxyethylene castor oil(EL-40) as the emulsifier and was free from co-emulsifier. The formula of the maximum oil loading was found as Chuanxiong oil∶EL-40∶water 3∶7∶90. Further, puera-rin successfully replaced up to 10% of the emulsifier in submicron emulsion. Eventually, the optimal drug-loading formula was determined as puerarin∶Chuanxiong oil∶EL-40∶water 7∶30∶63∶900. The quality evaluation results of the as-prepared submicron emulsion demonstrated that the average emulsion droplet size was 333.9 nm, the PDI 0.26, and the zeta potential-10.12 mV. The submicron emulsion had a good centrifugal stability and did not present any instable phenomena such as delamination and precipitation during its standing still for 50 days. The evaluation of in vitro drug release behavior indicated that the submicron emulsion was capable of releasing the drug completely. The puerarin-chuanxiong oil submicron emulsion prepared in this study possessed a stable quality and to some extent increased the solubility of puerarin along with a sustained-release effect. This study provided ideas for the clinical application of puerarin.
Emulsions ; Isoflavones ; Particle Size ; Solubility

Targeting the deficiencies of Lingzhu Powder, this study introduced the particle design technology to improve its quality. Based on the mechanism of particle design for powder and the characteristics of solvent evaporation method, composite particles consisting of Succinum, Cinnabaris, and artificial Bovis Calculus were prepared. And the powder properties of composite particles and physical mixtures as well as the content uniformity of toxic components were investigated for exploring the technological advantages of particle design in improving the quality of Lingzhu Powder. The results showed that the composite particles prepared using solvent evaporation method and particle design technology were micro-particles, and the stable agglomerate structure could be observed under SEM. Composite particles exhibited better fluidity and compliance in oral intake than physical mixtures. The differences in chromatism, bulk density, and content uniformity of the composite particles were smaller than those of physical mixtures, and the corresponding RSD values \[4.8%, 1.8%, 3.4%(bilirubin), and 0.63%(HgS), respectively\] were smaller. The solvent evaporation combined with particle design technology can be utilized to significantly improve the quality of Lingzhu Powder, which has provided new ideas for the optimization of the quality of traditional Chinese medicinal powder.
Particle Size ; Powders ; Solvents ; Technology

There are a lot of units used in Anesthesiology field. Sometimes, we could not compare two units describing the same physical category. For example, I cannot find reference materials explaining whether a 7 French catheter is larger than a 16 Gauge catheter. Furthermore, I would like to know why there are so many differences of blood calcium levels between regular check and intraoperative emergency reports. As for liquid drug concentrations, we usually use the mg/ml during a clinical practice, however, basic researchers report it as mole/liter (molarity, M). I would like to answer these questions. So, I have searched some references and have summarized them to explain length, concentration, temperature, particle size, pressure, and ratio units commonly used in our clinical practice, Anesthesiology.
Anesthesiology* ; Calcium ; Catheters ; Emergencies ; Particle Size

PURPOSE: We assessed the dynamic characteristics of 16 nebulizer/compressor combinations currently available in Korea. METHODS: The 16 nebulizer/compressor combinations(Pariboy Type 38/Long life, Pariboy Type N/ Long life, Pariboy Type N/Salter 8900, Pariboy Type N/LC, Devilbiss pulmoaid-LT/Hudson, Devilbiss pulmoaid/Hudson, Mesmed neb-300/Own, San-up 3040/Hudson, Midas(Basic)/Own, AirJolie 2/ Hudson, Thomas 1127/Salter 8900, Noel NE-2000/Salter 8900, Omron CX3/Hudson, Chang Woo CWN-100/Salter 8900, Voyage/Mefar, Chang Woo ASI-Pro/Medel jet pulse) were evaluated in terms of particle size and mass output. In addition, we determined the effects of nebulizer fill volume on mass output. RESULTS: Pariboy Type N/Long life has the highest respirable mass of 0.184 mg/min and Mesmed Neb-300/Own has the lowest 0.019 mg/min. Pariboy Type N/Long life has the highest mass output of 0.68 mg/min and the shortest mass median aerodynamic diameter(MMAD) of 3.76 m. All combinations other than Pariboy Type N/Long life produced a MMAD of over 5 m. MMAD over a 5 min nebulization ranged 3.76 to 9.83 m. There were no significant effects of fill volume on mass output. CONCLUSIONS: We concluded that there is a wide variation in performance of nebulizer/compressor combinations. The characteristics of nebulizer/compressor combinations should be considered in selecting products.
Korea* ; Nebulizers and Vaporizers ; Particle Size ; Respiratory Therapy

OBJECTIVETo characterize the flowability of traditional Chinese medicine (TCM) powders by using appropriate methods.

METHODWith highly flowable direct compression excipients and Chinese traditional medicine powder as raw materials, the flowability of material powders is determined by the Carr method and the Jenike method.

RESULTThe Carr method and the Jenike method for the determination of the flowability of Chinese herb extract powder and direct-pressing excipients have no obvious difference. But the flowability of Chinese herb extract powder is not as good as direct compression excipients.

CONCLUSIONFrom the characterization results of both methods, we can find that the Carr method better reflects the actual flowability of TCM extracts, while the Jenike method can be used for guiding the design of the hopper device.

To decrease the hemolysis side effect of puerarin, the basic formula and preparation of puerarin submicron emulsion were optimized and the physicochemical properties were evaluated. Puerarin submicron emulsions were prepared by phase inversion-ultrasound combining with phospholipids complexes technology. The effects of preparative parameters, such as emulsification time, stirring velocity and ultrasound time, on mean diameter, span of dispersity, entrapment efficiency and overall desirability were investigated. The three dimensional response surface graphs were produced by second-order polynomial and liner equation, which predict the optimal experiment conditions. All response variables were found to be greatly dependent on three independent variables. Second-order polynomial equations were fitter than liner equations for this study. The optimal emulsification time, stirring velocity and ultrasound time was 15 min, 2 000 r x min(-1), 30 min, respectively. The mean diameter, span of dispersity, entrapment efficiency, drug content and zeta potential of emulsions prepared by the method were 228.23 nm, 0.628 4, 84. 32%, 9.98 mg x mL(-1), - 29.03 mV, respectively. Puerarin submicron emulsion was prepared by the optimized preparation method. The narrow particle diameter distribution, high envelopment efficacy and good stability were obtained. The physicochemical properties were suitable for the requirement of the intravenous emulsion.
Emulsions ; Isoflavones ; administration & dosage ; chemistry ; Particle Size

AIMTo establish a spectrophotometric method for measurement of the sizes of liposomes for evaluating physical stability of liposomes.

METHODSThe sterically stabilized liposomes (SLs) were prepared by ethanol injection method and extrusion method. The mean cumulant diameters (D) of the vesicles were determined by electron microscopy and dynamic light scattering. On the basis of Rayleigh-Gans-Debye theory, the absorbance at 436 nm per unit lipid concentration (A436 nm/Cp) was measured as a function of vesicle diameter.

RESULTSlog(A436 nm/Cp) was closely related to logD (r2 > or = 0.93, n = 5).

CONCLUSIONThe absorbance of liposomes reflect their relative sizes and can be used to evaluate physical stability of liposomes.