STRATIFICATION IN ISOTHERMAL ICE-SLURRY PIPE FLOW

ABSTRACT A single-phase 3D model for isothermal laminar and turbulent flow of an ice slurry in a horizontal pipe is used to investigate the effects of the uniform inlet velocity and ice concentration on their axial evolution. The slurry is modeled as a Newtonian fluid with effective local properties depending on the local ice concentration. Despite the relative simplicity of this model (compared to the two-phase models used elsewhere) its numerical solution gives results which correctly reflect experimental observations. Specifically, these results show that as the fluid moves downstream the ice concentration increases in the upper part of the pipe and it decreases in the lower part. The velocity profile is principally influenced by the boundary layer growth close to the inlet but further downstream it becomes asymmetrical with respect to the horizontal symmetry plane with higher velocities in the lower part of the pipe. The differences between the values in the upper and lower parts of the pipe are much more important in the case of laminar flow. The results are analyzed by considering the phenomena influencing the ice particle movement (buoyancy and diffusion) and the relation between ice concentration and the thermophysical properties of the slurry. INTRODUCTION Ice slurries are mixtures of small ice particles (typically 0.1 to 1 mm of diameter) and a carrier liquid (a mixture of water and an additive such as glycol, sodium chloride or calcium carbonate which lowers the freezing temperature). They offer the possibility of enhanced energy transport density and energy storage due to the combined effects of sensible and latent heat. Applications include comfort cooling of buildings, food processing and the replacement of secondary refrigerants in ice rinks or supermarkets. Their thermophysical properties can be derived from linear weighing of the corresponding properties of the ice (which are essentially determined by the temperature) and the carrier liquid (which vary with the temperature and the concentration of the additive

Resected serous cystic neoplasms of the pancreas: Locally aggressive behavior as a predictor of malignant disease? A review of 158 patients with recommendations for treatment.

Background: Serous cystic neoplasms of the pancreas are regarded as a benign entity with rare malignant potential. Surgical resection is generally considered curative. Objective: To perform the largest single institution review of patients who underwent surgical resection for serous cystic neoplasms of the pancreas in the hopes of guiding future management. Methods: Between June 1988 and January 2005, 158 patients with serous cystic neoplasms of the pancreas underwent surgical resection. A retrospective analysis was performed. Univariate and multivariate models were used to determine factors influencing perioperative morbidity and mortality. Major complications were defined as pancreatic fistula or anastomotic leak, postoperative bleed, retained operative material, or death. Minor complications were defined as wound infection, postoperative obstruction/ileus requiring TPN, delayed gastric emptying, arrhythmia, or other infection. Results: The mean age of the patients was 62.1 years, with 75% being female. The majority of patients were symptomatic at presentation (63%), with abdominal pain as the most common symptom. Of the 158 patients, 75 underwent distal pancreatectomy, 65 underwent pancreaticoduodenectomy, 9 underwent central pancreatectomy, 5 underwent local resection or enucleation, and 4 underwent total pancreatectomy. Mean tumor diameter was 5.1 cm. Mean operative time was 277.5 minutes. Mean postoperative length of hospital stay was 11 days. One patient was diagnosed at presentation with serous cystadenocarcinoma. The remaining 157 patients were initially diagnosed with benign serous cystadenoma. One of three patients with locally aggressive benign disease later presented with metastatic disease. Resection margins for all 158 patients were negative for tumor, and only 1 (0.6%) showed lymph node involvement. There was one intraoperative death. The incidence of major perioperative complications was 18%, while the incidence of minor complications was 33%. Men were significantly more likely to experience minor perioperative complications (OR = 3.74, P = .008), while patients greater than 65 years showed a trend toward fewer major complications (OR = 0.36, P = .09). Conclusions: Serous cystic neoplasms of the pancreas which are surgically resected are typically seen in asymptomatic women, as 5 cm neoplasms which are predominantly benign. Most are resected via either a left or right sided pancreatectomy with low mortality risk, but with notable major or minor morbidity. Cystadenocarcinoma is a rare finding on initial resection of serous cystic neoplasms. However, initial pathology specimens exhibiting benign but locally aggressive neoplasia may indicate an increased likelihood of recurrence or metachronous metastasis

Recapitulation of tumor heterogeneity and molecular signatures in a 3D brain cancer model with decreased sensitivity to histone deacetylase inhibition

INTRODUCTION Physiologically relevant pre-clinical ex vivo models recapitulating CNS tumor micro-environmental complexity will aid development of biologically-targeted agents. We present comprehensive characterization of tumor aggregates generated using the 3D Rotary Cell Culture System (RCCS). METHODS CNS cancer cell lines were grown in conventional 2D cultures and the RCCS and comparison with a cohort of 53 pediatric high grade gliomas conducted by genome wide gene expression and microRNA arrays, coupled with immunohistochemistry, ex vivo magnetic resonance spectroscopy and drug sensitivity evaluation using the histone deacetylase inhibitor, Vorinostat. RESULTS Macroscopic RCCS aggregates recapitulated the heterogeneous morphology of brain tumors with a distinct proliferating rim, necrotic core and oxygen tension gradient. Gene expression and microRNA analyses revealed significant differences with 3D expression intermediate to 2D cultures and primary brain tumors. Metabolic profiling revealed differential profiles, with an increase in tumor specific metabolites in 3D. To evaluate the potential of the RCCS as a drug testing tool, we determined the efficacy of Vorinostat against aggregates of U87 and KNS42 glioblastoma cells. Both lines demonstrated markedly reduced sensitivity when assaying in 3D culture conditions compared to classical 2D drug screen approaches. CONCLUSIONS Our comprehensive characterization demonstrates that 3D RCCS culture of high grade brain tumor cells has profound effects on the genetic, epigenetic and metabolic profiles of cultured cells, with these cells residing as an intermediate phenotype between that of 2D cultures and primary tumors. There is a discrepancy between 2D culture and tumor molecular profiles, and RCCS partially re-capitulates tissue specific features, allowing drug testing in a more relevant ex vivo system

TSUGI : a framework for building PHP-based learning tools

Innovation on ICT-based learning depends on the ability of researchers, developers and services (and content) providers to push new kinds of tools and services in real life contexts. This implies that new developments need to be interoperable with the current LMS that are running almost everywhere. Thus, either new developments have to be custom built for every LMS or there is a real need for an interoperability standard Over the last 8 years IMS Global Learning Consortium has pushed the IMS Learning tools interoperability as the missing standard. IMS LTI has been developed in collaboration with the major LMS and tools authors in a long process where reference implementations and automated compliance tests have been created, and IMS LTI is supported for all the major commercial and open source LMS. But despite the collaborative open process there are different versions of the standard (Simple LTI, Basic LTI, LTI 1.0, LTI 1.1 and soon LTI 2.0) and there are subtle differences in the implementation of LTI provided by each LMS, which defeats the whole purpose of having an interoperability standard. For this reason the TSUGI project has been created: to provide a framework that makes as simple as possible to develop and deploy LTI applications.Peer ReviewedPostprint (published version

TSUGI : a framework for building PHP-based learning tools

Innovation on ICT-based learning depends on the ability of researchers, developers and services (and content) providers to push new kinds of tools and services in real life contexts. This implies that new developments need to be interoperable with the current LMS that are running almost everywhere. Thus, either new developments have to be custom built for every LMS or there is a real need for an interoperability standard Over the last 8 years IMS Global Learning Consortium has pushed the IMS Learning tools interoperability as the missing standard. IMS LTI has been developed in collaboration with the major LMS and tools authors in a long process where reference implementations and automated compliance tests have been created, and IMS LTI is supported for all the major commercial and open source LMS. But despite the collaborative open process there are different versions of the standard (Simple LTI, Basic LTI, LTI 1.0, LTI 1.1 and soon LTI 2.0) and there are subtle differences in the implementation of LTI provided by each LMS, which defeats the whole purpose of having an interoperability standard. For this reason the TSUGI project has been created: to provide a framework that makes as simple as possible to develop and deploy LTI applications.Peer Reviewe