Transient electrophoresis in a suspension of charged particles with arbitrary electric double layers.

The startup of electrophoretic motion in a suspension of spherical colloidal particles, which may be charged with constant zeta potential or constant surface charge density, due to the sudden application of an electric field is analytically examined. The unsteady modified Stokes equation governing the fluid velocity field is solved with unit cell models. Explicit formulas for the transient electrophoretic velocity of the particle in a cell in the Laplace transforms are obtained as functions of relevant parameters. The transient electrophoretic mobility is a monotonic decreasing function of the particle-to-fluid density ratio and in general a decreasing function of the particle volume fraction, but it increases and decreases with a raise in the ratio of the particle radius to the Debye length for the particles with constant zeta potential and constant surface charge density, respectively. On the other hand, the relaxation time in the growth of the electrophoretic mobility increases substantially with an increase in the particle-to-fluid density ratio and with a decrease in the particle volume fraction but is not a sensitive function of the ratio of the particle radius to the Debye length. For specified values of the particle volume fraction and particle-to-fluid density ratio in a suspension, the relaxation times in the growth of the particle mobility in transient electrophoresis and transient sedimentation are equivalent.

Transient electrophoresis of a charged porous particle.

The starting electrophoretic motion of a porous, uniformly charged, spherical particle, which models a solvent-permeable and ion-penetrable polyelectrolyte coil or floc of nanoparticles, in an arbitrary electrolyte solution due to the sudden application of an electric field is studied for the first time. The unsteady Stokes/Brinkman equations with the electric force term governing the fluid velocity fields are solved by means of the Laplace transform. An analytical formula for the electrophoretic mobility of the porous sphere is obtained as a function of the dimensionless parameters κa , λa , ρp/ρ , and νt/a2 , where a is the radius of the particle, κ is the Debye screening parameter, λ is the reciprocal of the square root of the fluid permeability in the particle, ρp and ρ are the mass densities of the particle and fluid, respectively, ν is the kinematic viscosity of the fluid, and t is the time. The electrophoretic mobility normalized by its steady-state value increases monotonically with increases in νt/a2 and κa , but decreases monotonically with an increase in ρp/ρ , keeping the other parameters unchanged. In general, a porous particle with a high fluid permeability trails behind an identical porous particle with a lower permeability and a corresponding hard particle in the growth of the normalized electrophoretic mobility The normalized electrophoretic acceleration of the porous sphere decreases monotonically with an increase in the time and increases with an increase in λa from zero at λa=0 .

Polychlorinated dibenzo-p-dioxins and dibenzofuran contents in fish and sediment near a pentachlorophenol contaminated site.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in sediment and fish of aqua farms close to a contaminated site of a pentachlorophenol production plant (CPDC-ASS) were investigated. The total PCDD/F I-TEQ level in sediment and fish ranged from 0.725 to 87.9 ng I-TEQ kg(-1)d.w.(-1) and 0.044 to 3.10 pg I-TEQ g(-1)w.w.(-1), respectively, meaning that the CPDC-ASS was a long-term exposure PCDD/F contaminated area. The four dominant congeners in sediment and fish were OCDD, OCDF, 1,2,3,4,6,7,8-HpCDF and 1,2,3,4,6,7,8-HpCDD. The correlated coefficient of total I-TEQ PCDD/F contents between fish and sediment was 0.82 (R(2)), indicating a positive correlation between exposure to PCDD/Fs in sediment and biota. In addition, the biota-to-sediment accumulation factors (BSAFs) values of low chlorinated PCDD/F congeners such as those of 2,3,7,8-TeCDD for Milkfish and Tilapia were 0.00739 and 0.00593, respectively, which were much higher than those of highly chlorinated congeners. For example, the BSAFs of OCDD for Milkfish and Tilapia were 0.000207 and 0.000277, respectively. A negative relationship of log K(ow) and log BSAF for PCDD/F congeners was found, and the highest value was observed at approximately K(ow)= 7.0-7.5. The results of this study provide valuable information for establishing the PCDD/F regulated standard for the sediment of fish ponds.

Leiomyosarcoma of the skin: review of the literature with an emphasis on prognosis and management.

Leiomyosarcoma (LMS) of the skin is rare, and no management guideline currently exists. Although LMS is historically classified as either dermal (cutaneous) or subcutaneous, definition for its classfication is inconsistent in the literature. Studies on the managenent of LMS are scarce, and there is no consensus on the appropriate surgical margin for the treatment of LMS. While a 1 cm margin may be sufficient in cutaneous LMS, wider margins may be required for subcutaneous tumors. Mohs micrographic surgery is a promising surgical modality for the treatment of cutaneous LMS. In this review, current knowledge on LMS is summarized and a practical approach to the management of this rare neoplasm is proposed.

Characterization of PCDD/Fs, PAHs, and heavy metals in a secondary aluminum smelter.

This study characterizes polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), and heavy metal concentrations in stack flue gas, workplace air, fly ash, bottom ash, and ambient air of a secondary aluminum smelter. The total PAH concentration in workplace air was dominated by 2- and 3-ring PAHs, accounting for 86.2% of the gas phase in the total PAHs. The PCDD/F concentrations in workplace air are 1-7 fold higher than that in ambient air. The mass distribution ratio for total PCDD/Fs was soil > ash > workplace air > ambient air > flue gas. Aluminum and Zn had the highest concentrations. A positive correlation existed between PCDD/Fs and PAHs concentrations (r(2) = 0.920). The operation of secondary aluminum smelter affects the pollutant concentrations and surrounding air quality. Experimental results suggest that besides the terminal control technologies for stack flue gases, engineering control technologies in the workplace need further improvement.

Lichen planus and lichenoid drug eruption after vaccination.

Lichen planus (LP) and lichenoid drug eruptions (LDEs) uncommonly occur after vaccination, especially for hepatitis B and influenza. The key initiating event that leads to the development of postimmunization LP or LDE is not well understood. There have been prior reports of an association between several vaccines and LP. In this study, we aim to characterize and review cases of LP and LDE after vaccination from the Vaccine Adverse Event Reporting System (VAERS) national database in the United States. Information on vaccine-associated LP and LDE was retrieved from the database (July 1990 to November 2014) to examine the frequency of LP or LDE after vaccination. Hepatitis B, influenza, and herpes zoster vaccines were the 3 most commonly associated vaccines. Patients with LP or LDE were significantly older compared to the reported adverse events (AEs) overall (P<.001). The median age of onset for LP and LDE was 47 years. The median time of onset of AEs was 14 days. It is important to obtain recent vaccination history in patients presenting with new-onset LP or LDE.

Lichen planus and dyslipidemia: a systematic review and meta-analysis of observational studies.

BACKGROUND: Lichen planus (LP) is a chronic inflammatory disease that has been shown to be positively associated with dyslipidemia. However, the magnitude and types of the underlying lipid abnormalities have not been investigated. This study aims to conduct a systematic review and meta-analysis to investigate the qualitative and quantitative association between LP and dyslipidemia. METHODS: A systematic search of studies published from inception to April 1, 2015, was conducted using MEDLINE, EMBASE, Web of Science, and Cochrane library databases. Meta-analyses of observational studies with both categorical and continuous outcome were performed. DerSimonian and Lard random effects models were utilized to calculate the pooled odds ratio and weighted mean difference (WMD). Publication bias was evaluated by funnel plot and Egger's test. RESULTS: Seven studies with 5242 subjects were included in this meta-analysis. Patients with LP were significantly more likely to have dyslipidemia, with a pooled odds ratio of 1.74 (95% confidence interval [CI]: 1.19-2.54, P = 0.004). LP was associated with higher levels of triglycerides (WMD 83.37 mg/dl, 95% CI 0.62-166.12, P = 0.048), low-density lipoprotein (18.75 mg/dl, 95% CI -17.21 to 54.72, P = 0.307), total cholesterol (19.22 mg/dl, 95% CI -8.80 to 47.25, P = 0.179), and lower levels of high-density lipoprotein cholesterol (-8.96 mg/dl, 95% CI -21.22 to 3.30, P = 0.152). CONCLUSIONS: Despite considerable heterogeneity, this study demonstrated that LP was significantly associated with an increased risk of dyslipidemia and higher triglyceride levels. For patients presenting with LP, physicians should be cognizant of this association and consider screening them for dyslipidemia.