Numerical prediction of ac electro-osmotic flows around polarized electrodes.

In this paper we present an interactive numerical method that can predict ac electro-osmotic flows around completely polarized electrodes. In this method the slip velocity on the electrode surface is calculated by numerically solving the Laplace equation for the potential in the bulk coupled with the dynamical equation for the surface charge density on the electrodes; here the dynamical equation has been derived from the asymptotic solutions of the Poisson-Nernst-Planck equation for the potential drop across the electrical thin layer near the electrode. A unique feature of this study is that the effect of nonspecific ion adsorption is considered. The numerical code was applied to the two-dimensional ac electro-osmotic flow above a pair of coplanar electrodes, and the solutions compared well with the experimental data reported in the literature. We investigated the effect of various parameters on the slip velocity distribution, such as the ac frequency, the electrode length, the effective Stern-layer thickness, and the adsorption coefficients.

Asymptotic analysis of ion transport in a nonlinear regime around polarized electrodes under ac.

In this paper we present the asymptotic solutions of the Poisson-Nernst-Planck equations describing ion transport near a polarized electrode under ac. The solutions can be described in terms of the triple-layer (or quadruple-layer in the transient period) structure. In the thinnest inner layer outside the Stern layer, cations and anions show alternating charging with the same frequency as ac. Next to the inner layer is a buffer region or "middle layer" in which cations and anions exhibit the same behavior but with a frequency double that of the ac frequency. The outer layer shows quasisteady diffusion of ions expanding toward the bulk region and vanishes after the transient period. The potential drop occurs only through the inner layer, which together with the concentrations can be obtained by solving a simple dynamical equation. The asymptotic method is applied to the one-dimensional ion-transport within two parallel facing electrodes and the solutions compare well with the ones obtained with robust numerical methods for the original full equations at various ranges of parameters. We also considered the effect of ion adsorption at the interface between the Stern and inner layers on the ion transport and the virtual slip velocity for the case of facing electrodes.

Synchronous Hodgkin's disease and granulocytic sarcoma with no prior therapy.

We describe a case of simultaneous nodular sclerosing Hodgkin's disease and a granulocytic sarcoma in a cervical lymph node without any previous therapy. The condition evolved into acute myelogenous leukemia approximately 8 months after the initial diagnosis of the granulocytic sarcoma. The unexpected presence of a granulocytic sarcoma made the diagnosis challenging, and appropriate immunohistochemical studies were required for accurate diagnosis. To the best our knowledge, this is the first report of synchronous Hodgkin's disease and granulocytic sarcoma with eventual development of acute myelogenous leukemia.

Angiotropic (intravascular) large cell lymphoma of T-cell phenotype presenting as acute appendicitis in a patient with acquired immunodeficiency syndrome.

We describe a patient with acquired immunodeficiency syndrome who presented with acute appendicitis but was found to have angiotropic large cell lymphoma (ALCL) by pathologic examination of the appendectomy specimen, without acute inflammation. Very rare cases of angiotropic large cell lymphoma have been reported in patients with human immunodeficiency virus infection, and most cases of this rare lymphoma are of B-cell origin, but in this instance immunohistochemical analysis showed a T-cell phenotype.

Lymphoid cell aggregates: a useful clue in the fine-needle aspiration diagnosis of follicular lymphomas.

Among the various types of lymphoma, follicular lymphoma (FL) is known to have significant limitations in cytologic diagnosis by the fine-needle aspiration (FNA) method. The diagnostic accuracy (DA) for non-Hodgkin's lymphoma (NHL) by FNA was evaluated by review of 82 cases of histologically proved NHL after prior FNA. The DA for all NHLs was 66% (54/82), and that for low-grade lymphomas, including small lymphocytic lymphoma, follicular small-cleaved cell lymphoma, and follicular mixed cell lymphoma, was 71% (12/17). The DA for FL was 69% (11/16). Review of individual surgical and cytologic materials from FLs revealed a tendency to show fibrosis in the cytologically false-negative group and diffuse areas of lymphoma in the true-positive group. The presence of "aggregation" of uniform lymphoid cells, probably due to cell adhesions with the support of dendritic reticulum cells, was seen in 55% of true-positive FL (6/11). In contrast, only 28% of true-positive diffuse large cell lymphomas (5/18) showed a mild degree of aggregation, and none of 7 cases of true-positive diffuse small-cleaved cell lymphoma showed this feature. The aggregation of cells was not pathognomonic of FL, but its presence with a homogeneous cellular constituent and the paucity of tingible-body macrophages helped us to predict FL. Also, it was a feature distinguishing FL from diffuse small-cleaved cell lymphoma (P = 0.025).

Competition between the bulk and the dissociation layer in electrohydrodynamic flow of dielectric liquid around coplanar electrodes.

An experimental and numerical study has been conducted on the electrohydrodynamic flow around coplanar electrodes with a dielectric liquid: dodecane mixed with the surfactant Span 80. It is shown that the flow is asymmetric, although the electrode is symmetrically arranged, and numerically, we have shown that a difference in the ionic size can reproduce such asymmetric patterns. It is also found that the dissociation layer effect becomes more important in determining the flow pattern than is predicted from the conventional theory where the Langevin formula is used for the recombination constant. In numerical simulations, reducing the recombination constant to 0.035-0.055 times the Langevin value turned out to produce good comparisons between the experimental and the numerical results for the electrode pairs with 1 and 0.2 mm gaps.

Asymptotic and numerical analysis of electrohydrodynamic flows of dielectric liquid.

We perform an asymptotic analysis of electrohydrodynamic (EHD) flow of nonpolar liquid subjected to an external, nonuniform electric field. The domain of interest covers the bulk as well as the thin dissociation layers (DSLs) near the electrodes. Outer (i.e., bulk) equations for the ion transport in hierarchical order of perturbation parameters can be expressed in linear form, whereas the inner (i.e., DSL) equations take a nonlinear form. We derive a simple formula in terms of various parameters which can be used to estimate the relative importance of the DSL-driven flow compared with the bulk-driven flow. EHD flow over a pair of cylindrical electrodes is then solved asymptotically and numerically. It is found that in large geometric scale and high ion concentration the EHD flow is dominated by the bulk-charge-induced flow. As the scale and concentration are decreased, the DSL-driven slip velocity increases and the resultant flow tends to dominate the domain and finally leads to flow reversal. We also conduct a flow-visualization experiment to verify the analysis and attain good agreement between the two results with parameter tuning. We finally show, based on the comparison of experimental and numerical solutions, that the rate of free-ion generation (dissociation) should be less than the one predicted from the existing formula.

Numerical study on the bulk instability of constant-current conduction in cation-exchange membranes.

Numerical simulation of two-dimensional bulk instability of the one-dimensional conduction state in an electrolyte confined between a pair of cation-exchange membranes subjected to an external voltage is conducted under an assumption of constant current. By employing variable grids, we resolve the problem of sensitive dependence of the numerical solutions to the grid refinement in particular at a current close to the limiting value. In fact, the full range of parameters, i.e., Schmidt number, Peclet number, diffusivity ratio, and current, is considered in this study in obtaining the stability chart. It turns out that the Schmidt number exerts almost no influence on the results. From the neutral curves in the chart of the parameter space (current versus diffusivity ratio, i.e., cation diffusivity divided by anion diffusivity) we confirm that the system tends to be unstable at high Peclet numbers, high currents, and low diffusivity ratios. As the diffusivity ratio is increased the instability mode switches from the monotonic to the oscillatory type, and the critical diffusivity ratio for the switching is found to be decreased as the Peclet number decreases. At the switching, no jump in the neutral curves is found, contrary to the earlier result, because the wave number is set free to change in this study. The stability chart obtained in this study represents the true boundaries in discriminating the stable from the unstable parameter sets because the critical eigenvalues constituting the chart are sought for the entire possible range of the wave numbers and the frequencies.

Folate intake and the risk of colorectal cancer in a Korean population.

BACKGROUND: Folate, a water-soluble B vitamin and one of the major micronutrients in vegetables, is known as an essential factor for the de novo biosynthesis of purines and thymidylate, and it plays an important role in DNA synthesis and replication. Thus, folate deficiency results in ineffective DNA synthesis, and has been shown to induce the initiation and progression of colorectal cancer (CRC). Recently, the incidence of CRC in Korea has increased markedly in both men and women; this trend may be related to the adoption of a more 'westernized' lifestyle, including dietary habits. OBJECTIVE: A hospital-based case-control study was conducted to examine the relationship between folate intake and the risk of CRC within a Korean population. METHODS: A total of 596 cases and 509 controls, aged 30-79 years, were recruited from two university hospitals. Site- and sex-specific odds ratios (ORs) were estimated using logistic regression models. RESULTS: Cases were more frequently found to have a family history of CRC among first-degree relatives, to consume more alcohol, to be more likely current smokers and less likely to participate in vigorous physical activity than the controls. In the overall data for men and women combined, multivariate ORs (95% confidence interval (CI), P for trend) comparing the highest vs the lowest quartile of dietary folate intake were: 0.47 (0.32-0.69, <0.001) for CRC, 0.42 (0.26-0.69, <0.001) for colon cancer and 0.48 (0.28-0.81, 0.007) for rectal cancer. An inverse association was also found in women with dietary folate intake: 0.36 (0.20-0.64, <0.001) for CRC, 0.34 (0.16-0.70, 0.001) for colon cancer and 0.30 (0.12-0.74, 0.026) for rectal cancer, but not in men. In addition, the total folate intake of women was strongly associated with a reduced risk of rectal cancer (OR, 0.38; 95% CI, 0.17-0.88; P for trend=0.04). CONCLUSION: We found a statistically significant relationship between higher dietary folate intake and reduced risk of CRC, colon cancer and rectal cancer in women. A significant association is indicated between higher total folate intake and reduced risk of rectal cancer in women.

Fine-needle aspiration biopsy of granulocytic sarcoma: a clinicopathologic study of 27 cases.

BACKGROUND: Because of morphologic similarities, the differential diagnosis of granulocytic sarcoma (GS) in fine-needle aspiration (FNA) specimens includes non-Hodgkin or Hodgkin lymphoma, extramedullary hematopoiesis, poorly differentiated carcinoma, and infection. METHODS: Twenty-six FNAs and 1 pleural effusion fluid specimen of GS obtained from 23 patients were reviewed for cytomorphologic features and clinical characteristics. The cases were categorized as blastic, immature, or mature GS based on the population of the cells present on the smears. RESULTS: The patients included 18 men and 5 women (mean age, 54 years). Aspiration sites included subcutaneous or soft tissue (15 cases), lymph nodes (5 cases), bones (3 cases), testis (1 case), ileum (1 case), and liver (1 case). One sample of pleural effusion fluid also was included. Review of the patients' clinical history revealed that GS was secondary to chronic myelogenous leukemia (CML) in 17 patients, was secondary to chronic myelomonocytic leukemia (CMML) in 2 patients, and was secondary to acute myelogenous leukemia in 2 patients. GS preceded the manifestation of CML in one patient and of CMML in another patient. Based on the proportions of cells, morphologic classification was attempted and revealed blastic GS in 8 aspirates and 1 pleural effusion fluid specimen, immature GS in 13 aspirates, and mature GS in 5 aspirates. Twelve of 22 specimens from extranodal sites (55%) demonstrated lymphoglandular bodies in the background. Five aspirates showed rare eosinophilic myelocytes. Auer rods were not identified in any of the aspirates. Immunophenotypic and histochemical studies confirmed myeloid and/or myelomonocytic differentiation. CONCLUSIONS: GS especially can be confused with non-Hodgkin lymphoma because of morphologic similarities of the blasts to large cell lymphoma, the presence of lymphoglandular bodies, and the rarity of Auer rods and eosinophilic myelocytes. In conjunction with careful cytomorphologic evaluation, knowledge of the patient's clinical history and use of appropriate immunophenotypic studies should lead to a correct diagnosis.

Clonal changes in inflammatory pseudotumor of the lung: a case report.

BACKGROUND: Pulmonary inflammatory pseudotumor, also known as plasma cell granuloma among many other names, is widely believed to be an inflammatory or reactive lesion rather than a neoplasm, although its pathogenesis is still controversial. METHODS: Cytogenetic analysis was performed on a lung mass that showed typical clinical and pathologic features of inflammatory pseudotumor. Ultrastructural and immunohistochemical studies were performed in addition to routine histologic examination. RESULTS: Cytogenetic study of the lesion revealed clonal anomalies of t(1;2)(q21;p23) and del(4)(q27). The patient, a 30-year-old woman, presented with an asymptomatic but enlarging right lower lobe mass for which partial right lower lobectomy was performed. The lung mass was well circumscribed radiographically and grossly. Microscopically, it was characterized by a loosely arranged spindle cell proliferation with prominent plasma cell infiltration. Fibroblastic and myofibroblastic differentiation of the spindle cells was demonstrated by ultrastructural and immunohistochemical studies. CONCLUSION: To the authors' knowledge, this is the first report of clonal cytogenetic changes in a clinically and pathologically typical case of inflammatory pseudotumor in the lung. This finding suggests that pulmonary inflammatory pseudotumor might be a true neoplasm rather than a purely inflammatory or reactive lesion.

Experimental extrinsic allergic alveolitis and pulmonary angiitis induced by intratracheal or intravenous challenge with Corynebacterium parvum in sensitized rats.

Extrinsic allergic alveolitis and pulmonary sarcoidosis are granulomatous diseases of the lung for which clinical presentation and anatomic site of granuloma formation differ. Extrinsic allergic alveolitis is caused by inhaled antigens, whereas the nature and source of the inciting antigen in sarcoidosis is unknown. To test the hypothesis that the route via which antigen is introduced to the lung contributes to the clinicopathological presentation of pulmonary granulomatous disease, rats immunized with intravenous (i.v.) Corynebacterium parvum were challenged after 2 weeks with either intratracheal (i.t.) or i.v. C. parvum. The granulomatous inflammation elicited by i.t. challenge predominantly involved alveolar spaces and histologically simulated extrinsic allergic alveolitis. In contrast, the inflammation induced by i.v. challenge was characterized by granulomatous angiitis and interstitial inflammation simulating sarcoidosis. Elevations of leukocyte counts and TNF levels in bronchoalveolar fluid, which reflect inflammation in the intra-alveolar compartment, were much more pronounced after i.t. than after i.v. challenge. Tumor necrosis factor, interleukin-6, CC chemokine, CXC chemokine, and adhesion molecule mRNA and protein expression occurred in each model. In conclusion, i.t. or i.v. challenge with C. parvum in sensitized rats caused pulmonary granulomatous inflammation that was histologically similar to human extrinsic allergic alveolitis and sarcoidosis, respectively. Although the soluble and cellular mediators of granulomatous inflammation were qualitatively similar in both disease models, the differing anatomic source of the same antigenic challenge was responsible for differing clinicopathological presentations.