The hydrodynamic characteristics of upflow anaerobic sludge blanket (UASB) reactors were investigated in this study. A UASB reactor was visualized as being set‐up of a number of continuously stirred tank reactors (CSTRs) in series. An increasing‐sized CSTRs (ISC) model was developed to describe the hydrodynamics of such a bioreactor. The gradually increasing tank size in the ISC model implies that the dispersion coefficient decreased along the axial of the UASB reactor and that its hydrodynamic behavior was basically dispersion‐controlled. Experimental results from both laboratory‐scale H2‐producing and full‐scale CH4‐producing UASB reactors were used to validate this model. Simulation results demonstrate that the ISC model was better than the other models in describing the hydrodynamics of the UASB reactors. Moreover, a three‐dimensional computational fluid dynamics (CFD) simulation was performed with an Eulerian‐Eulerian three‐phase‐fluid approach to visualize the phase holdup and to explore the flow patterns in UASB reactors. The results from the CFD simulation were comparable with those of the ISC model predictions in terms of the flow patterns and dead zone fractions. The simulation results about the flow field further confirm the discontinuity in the mixing behaviors throughout a UASB reactor. © 2008 American Institute of Chemical Engineers AIChE J, 2009

BACKGROUND: Sentinel lymph node biopsy (SLNB) has emerged as a widely used staging procedure for cutaneous melanoma. However, debate remains around the accuracy and prognostic implications of SLNB for cutaneous melanoma arising in the head and neck, as previous reports have demonstrated inferior results to those in nonhead and neck regions. Through the largest single-institution series of head and neck melanoma patients, the authors set out to demonstrate that SLNB accuracy and prognostic value in the head and neck region are comparable to other sites. METHODS: A prospectively collected database was queried for cutaneous head and neck melanoma patients who underwent SLNB at the University of Michigan between 1997 and 2007. Primary endpoints included SLNB result, time to recurrence, site of recurrence, and date and cause of death. Multivariate models were constructed for analyses. RESULTS: Three hundred fifty-three patients were identified. A sentinel lymph node was identified in 352 of 353 patients (99.7%). Sixty-nine of the 353 (19.6%) patients had a positive SLNB. Seventeen of 68 patients (25%) undergoing completion lymphadenectomy after a positive SLNB result had at least 1 additional positive nonsentinel lymph node. Patients with local control and a negative SLNB failed regionally in 4.2% of cases. Multivariate analysis revealed positive SLNB status to be the most prognostic clinicopathologic predictor of poor outcome; hazard ratio was 4.23 for SLNB status and recurrence-free survival (P < .0001) and 3.33 for overall survival (P < .0001). CONCLUSIONS: SLNB is accurate and its results are of prognostic importance for head and neck melanoma patients. Cancer 2012;118:1040-

Epithelial growth, branching, and canalization are important morphogenetic events of the rodent ventral prostate (VP) that take place during the first postnatal week. In this study, we evaluated the effect of knocking out MMP‐2 (MMP‐2−/−), by examining developmental and structural aspects of the VP in MMP‐2−/− mice. Neonate (day 6) MMP‐2−/− mice showed fewer epithelial tips, a lower epithelial cell proliferation rate, and also reticulin fiber accumulation. The VP of adult MMP‐2−/− mice showed lower relative weight, smaller epithelial and smooth‐muscle cell volume, and a larger amount of thicker reticulin fibers. No differences in cell proliferation or apoptotic index were noted between adult MMP‐2−/− and wild‐type mice. MMP‐9 was found in the adult MMP‐2−/−, but not in the wild‐type. In conclusion, MMP‐2 function is essential for the epithelial morphogenesis of the mouse VP, and expression of MMP‐9 is not sufficient for acquisition of the normal adult histology. Developmental Dynamics 239:2386–2392, 2010. © 2010 Wiley‐Liss, Inc.

A B S T R A C T PurposeMerkel cell carcinoma (MCC) is a relatively rare, potentially aggressive cutaneous malignancy. We examined the clinical and histologic features of primary MCC that may correlate with the probability of a positive sentinel lymph node (SLN). MethodsNinety-five patients with MCC who underwent SLN biopsy at the University of Michigan were identified. SLN biopsy was performed on 97 primary tumors, and an SLN was identified in 93 instances. These were reviewed for clinical and histologic features and associated SLN positivity. Univariate associations between these characteristics and a positive SLN were tested for by using either the 2 or the Fisher's exact test. A backward elimination algorithm was used to help create a best multiple variable model to explain a positive SLN. ResultsSLN positivity was significantly associated with the clinical size of the lesion, greatest horizontal histologic dimension, tumor thickness, mitotic rate, and histologic growth pattern. Two competing multivariate models were generated to predict a positive SLN. The histologic growth pattern was present in both models and combined with either tumor thickness or mitotic rate. ConclusionIncreasing clinical size, increasing tumor thickness, increasing mitotic rate, and infiltrative tumor growth pattern were significantly associated with a greater likelihood of a positive SLN. By using the growth pattern and tumor thickness model, no subgroup of patients was predicted to have a lower than 15% to 20% likelihood of a positive SLN. This suggests that all patients presenting with MCC without clinical evidence of regional lymph node disease should be considered for SLN biopsy.