The Experts below are selected from a list of 14184 Experts worldwide ranked by ideXlab platform
Yongwei Wang - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of the thermal fluctuations in hot and cold fluids mixing in a t junction filled with spherical particles
Applied Thermal Engineering, 2014Co-Authors: Yongwei Wang, Ping WangAbstract:Abstract The turbulent mixing of hot and cold fluids in a T-junction filled with a porous medium composed of stainless steel spherical particles has been experimentally investigated in order to determine the influence of the ratio of the flow in the Main Duct to that in the branch Duct, and the temperature difference between the mixing fluids, on the thermal fluctuations. The temperature of the cold water in the branch Duct was fixed at 22.5 °C, and the temperature differences between the cold water and the hot water in the Main Duct were 7.5 °C, 15 °C or 20 °C. The ratios of the flow in the Main Duct to that in the branch Duct were 2, 4, or 8. The experimental results indicated that the largest fluctuations of instantaneous temperatures were in the middle and upper part of the mixing zone. On increasing the flow ratio, the region of strong temperature fluctuations became smaller. The distribution of hot and cold water in the mixing zone was found to depend on the flow ratio, which had a significant effect on the distribution of normalized mean and root mean square temperatures. The temperature difference had a limited effect on the temperature fluctuations.
Ping Wang - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of the thermal fluctuations in hot and cold fluids mixing in a t junction filled with spherical particles
Applied Thermal Engineering, 2014Co-Authors: Yongwei Wang, Ping WangAbstract:Abstract The turbulent mixing of hot and cold fluids in a T-junction filled with a porous medium composed of stainless steel spherical particles has been experimentally investigated in order to determine the influence of the ratio of the flow in the Main Duct to that in the branch Duct, and the temperature difference between the mixing fluids, on the thermal fluctuations. The temperature of the cold water in the branch Duct was fixed at 22.5 °C, and the temperature differences between the cold water and the hot water in the Main Duct were 7.5 °C, 15 °C or 20 °C. The ratios of the flow in the Main Duct to that in the branch Duct were 2, 4, or 8. The experimental results indicated that the largest fluctuations of instantaneous temperatures were in the middle and upper part of the mixing zone. On increasing the flow ratio, the region of strong temperature fluctuations became smaller. The distribution of hot and cold water in the mixing zone was found to depend on the flow ratio, which had a significant effect on the distribution of normalized mean and root mean square temperatures. The temperature difference had a limited effect on the temperature fluctuations.
Carlos Fernandezdel Castillo - One of the best experts on this subject based on the ideXlab platform.
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surgical management of intraDuctal papillary mucinous neoplasm with Main Duct involvement an international expert survey and case vignette study
Surgery, 2018Co-Authors: Lianne Scholte, Paul Fockens, Nadine C M Van Huijgevoo, Marco J Uno, Sohei Satoi, A Sauvane, Christophe L Wolfgang, Suresh T. Chari, Carlos Fernandezdel Castillo, Marco Del ChiaroAbstract:Background: The risk of invasive cancer in resected intraDuctal papillary mucinous neoplasm with Main pancreatic Duct involvement is 33%–60%. Most guidelines, therefore, advise resection of Main Duct intraDuctal papillary mucinous neoplasm and mixed type intraDuctal papillary mucinous neoplasm in surgically fit patients, although advice on the surgical strategy (partial or total pancreatectomy) differs. We performed a survey amongst international experts to guide the design of future studies and help to prepare for a single international set of guidelines. Methods: An online survey including case vignettes was sent to 221 international experts who had published on Main Duct/mixed type intraDuctal papillary mucinous neoplasm in the previous decade and to all surgeon and gastroenterologist members of the pancreatic cyst guideline committees of the European Study Group and the International Association of Pancreatology. Results: Overall, 97 experts (67 surgeons, 30 gastroenterologists) from 19 countries replied (44% response rate). Most (93%) worked in an academic hospital, with a median of 15 years’ experience with intraDuctal papillary mucinous neoplasm treatment. In Main Duct/mixed type intraDuctal papillary mucinous neoplasm patients with pancreatic Duct dilation (>5 mm) in the entire pancreas, 41% (n = 37) advised nonoperative surveillance every 3–6 months, whereas 59% (n = 54) advised operative intervention. Of those who advised operative intervention, 46% (n = 25) would perform a total pancreatectomy and 31% (n = 17) pancreatoduodenectomy with follow-up. No structural differences in advice were seen between surgeons and gastroenterologists, between continents where the respondents lived, and based on years of experience. Conclusion: This international survey identified a clinically relevant lack of consensus in the treatment strategy in Main Duct/mixed type intraDuctal papillary mucinous neoplasm among experts. Studies with long-term follow-up including quality of life after partial and total pancreatectomy for Main Duct/mixed type intraDuctal papillary mucinous neoplasm are required.
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Not all mixed-type intraDuctal papillary mucinous neoplasms behave like Main-Duct lesions: implications of minimal involvement of the Main pancreatic Duct.
Surgery, 2014Co-Authors: Klaus Sahora, Carlos Fernandezdel Castillo, Giovanni Marchegiani, Fei Dong, Sarah P. Thayer, Cristina R. Ferrone, Dushyant V. Sahani, William R. Brugge, Andrew L. Warshaw, Keith D. LillemoeAbstract:Background The malignant potential of intraDuctal mucinous neoplasm of the pancreas (IPMN) is associated closely with Main pancreatic Duct (MPD) involvement. Because mixed-type IPMN is thought to have the same malignant potential as that of Main-Duct (MD)-IPMN, resection is recommended; however, the biological nature of mixed-type IPMN with only minimal involvement of MPD (min-mix-IPMN) may be different. Methods A prospective database of 404 resected IPMNs was re-reviewed to subclassify mixed-type IPMNs. We defined min-mix-IPMN as absence of gross abnormalities (except for dilatation) of MPD and noncircumferential microscopic involvement of MPD limited to few sections. Results We identified 46 min-mix-IPMNs, 163 IPMNs with extensive involvement of MPD (ex-mix-IPMN), 175 branch-Duct (BD)-IPMNs, and 20 MD-IPMNs. The majority of min-mix-IPMNs were found incidentally and increased cyst size on surveillance was the leading operative indication. The median diameter of MPD was 2 mm in min-mix-IPMN versus 9 mm in ex-mix-IPMN (P Conclusion Min-mix-IPMN often presents with no MPD dilation and is an incidental finding by microscopic examination. min-mix-IPMN shares the pathologic features and less aggressive biology with BD-IPMN. We propose that min-mix-IPMN be categorized differently than ex-mix-IPMN.
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Timing of Resection of Main-Duct IPMN
Intraductal Papillary Mucinous Neoplasm of the Pancreas, 2013Co-Authors: Klaus Sahora, Carlos Fernandezdel CastilloAbstract:Considering the high prevalence of malignancy in MD-IPMN, the international consensus guidelines for the management of IPMN and MCN of the pancreas recommend surgical resection of MD-IPMN for all surgically fit patients. The extent and type of preoperative work-up in patients with MD-IPMN should be orientated on the nature of the presenting symptoms, the certainty of the diagnosis, the likelihood that malignancy is present, and the age and surgical risk of the patient. In frail patients a primary observational approach, until the onset of symptoms or the appearance of findings suspicious for malignancy, may be a compromise strategy. A standard pancreaticoduodenectomy or distal pancreatectomy is the procedure of choice. However, it is important that patients have been preoperatively informed, not only about the extent of the planned procedure but also about the probability of an extended resection going as far as a total pancreatectomy.
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Natural History and Malignant Change of Main Duct IPMN
Intraductal Papillary Mucinous Neoplasm of the Pancreas, 2013Co-Authors: Klaus Sahora, Carlos Fernandezdel CastilloAbstract:Among the exocrine tumors of the pancreas, intraDuctal papillary mucinous neoplasms (IPMNs) have gained increasing attention in the last decade. MD-IPMNs are predominantly (>50 %) composed of intestinal-type epithelium, producing thick mucus. In similarity to other epithelial neoplasms, MD-IPMN follows an “adenoma–carcinoma sequence” with progression into invasive cancer over the course of several years. On average, patients with malignant MD-IPMN are 4–6 years older than those with low- to moderate-grade dysplasia. There are no reliable predictors of malignancy for patients with MD-IPMN, although several studies have described clinical and radiologic features that are more common in MD-IPMN carcinoma. Like in Ductal adenocarcinoma of the pancreas, jaundice and a recent onset or deterioration of diabetes mellitus are highly suspicious for malignancy. Significant effort has been made to understand the molecular pathogenesis of MD-IPMNs. Various molecular characteristics have been described in both MD-IPMN and BD-IPMN carcinoma, showing numerous parallels to conventional Ductal carcinoma of the pancreas.
Kwan-hao Leung - One of the best experts on this subject based on the ideXlab platform.
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Numerical and experimental investigation of sound transmission of a tee‐junction in a rectangular Duct at higher‐order modes.
The Journal of the Acoustical Society of America, 2010Co-Authors: Siu-kit Lau, Kwan-hao LeungAbstract:Sound transmission and scattering properties in higher‐order modes across the tee‐junction of a rectangular Duct used in ventilation and air‐conditioning system were investigated numerically and experimentally. High‐sound transmission of the fundamental mode and higher‐order modes across the Main Duct is observed at eigen‐frequencies of the Main Duct. The resonance of branch modes is suppressed by the weak modal coupling of the branch‐modes and the traveling wave in the Main Duct at or very close to the eigen‐frequencies of the sidebranch, which results in high‐sound transmission of the fundamental mode and higher‐order modes across the Main Duct and excitation of the branch modes at higher frequencies. Increases in sound scattering into higher‐order mode are found when the non‐planar or longitudinal branch‐mode excited. In the case of co‐excitation of the longitudinal branch‐mode and non‐planar branch‐modes, a broader band‐stop action in sound transmission has been observed. The results of numerical simu...
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Transmission characteristics of a tee-junction in a rectangular Duct at higher-order modes
The Journal of the Acoustical Society of America, 2009Co-Authors: Siu-kit Lau, Kwan-hao LeungAbstract:Numerical and experimental studies were undertaken to characterize the noise transmission and scattering properties in higher-order modes across the tee-junction of a rectangular Duct used in ventilation and air-conditioning systems. To measure these properties, a formulation of a transmission matrix based on the transfer function and a two-microphone method was devised. The measurement of modal sound transmission and scattering coefficients is demonstrated for a Duct element in a rectangular Duct. The results of numerical simulations were verified by experiments. The results show that sound transmissions of fundamental mode and higher-order modes across the Main Duct are high at the eigen-frequencies of the Main Duct and sidebranch. Weak modal coupling of the branch-modes and the traveling wave in the Main Duct is observed at or very close to the eigen-frequencies of the sidebranch, which shifts excitation of the higher-order branch-modes at higher frequencies. A decrease in sound transmission and increase in sound scattering into higher-order modes occur with excitation of the axial branch-mode. Excitation of the longitudinal branch-mode due to branch-end reflection also results in lower sound transmission of higher-order modes across the junction along the Main Duct.
Woo Jung Lee - One of the best experts on this subject based on the ideXlab platform.
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Laparoscopic-assisted spleen-preserving and pylorus-preserving total pancreatectomy for Main Duct type intraDuctal papillary mucinous tumors of the pancreas: a case report.
Surgical Laparoscopy Endoscopy & Percutaneous Techniques, 2011Co-Authors: Dong Hyun Kim, Chang Moo Kang, Woo Jung LeeAbstract:Minimally invasive and function-preserving pancreatectomy would be the ideal approach for benign and borderline malignant tumors of the pancreas. Total pancreatectomy can be indicated for the Main Duct type of intraDuctal papillary mucin-producing tumor (IPMT) to achieve radical resection. Recently, several studies advocating total pancreatectomy in IPMT have been published, but they are all believed to be done by conventional laparotomy. Herein, we report a case of a 72-year-old female patient who successfully underwent laparoscopic-assisted total pancreatectomy with the spleen and pylorus preserved in borderline malignant Main Duct type IPMT. A marginal ulcer around the duodenojejunostomy was developed, but managed by a proton-pump inhibitor. She was discharged 20 days after surgery. She was followed for more than 2 years without evidence of tumor recurrence. Her blood sugar level was well controlled by insulin pump therapy and image study showed well-preserved spleen function.
