336 research outputs found

    Direct and inverse pumping in flows with homogeneous and non-homogeneous swirl

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    The conditions in which meridional recirculations appear in swirling flows above a fixed wall are analysed. In the classical Bodew\"adt problem, where the swirl tends towards an aysmptotic value away from the wall, the well-known "tea-cup effect" drives a flow away from the plate at the centre of the vortex. Simple dimensional arguments applied to a single vortex show that if the intensity of the swirl decreases away from the wall, the sense of the recirculation can be inverted, and that the associated flow rate scales with the swirl gradient. Only if the flow is quasi-2D, does the classical tea-cup effect take place. This basic theory is confirmed by numerical simulations of a square array of steady, electrically driven vortices. Experiments in the turbulent regimes of the same configuration reveal that these mechanisms are active in the average flow and in its fluctuating part. The mechanisms singled out in this letter provide an explanation for previously observed phenomena in electrolyte flows. They also put forward a possible mechanism for the generation of helicity in flows close to two-dimensionality, which plays a key role in the transition between 2D and 3D turbulence

    Importance of histological tumor response assessment in predicting the outcome in patients with colorectal liver metastases treated with neo-adjuvant chemotherapy followed by liver surgery

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    Background: The purpose of the study was to characterize histological response to chemotherapy of hepatic colorectal metastases (HCRM), evaluate efficacy of different chemotherapies on histological response, and determine whether tumor regression grading (TRG) of HCRM predicts clinical outcome. Patients and methods: TRG was evaluated on 525 HCRM surgically resected from 181 patients, 112 pretreated with chemotherapy. Disease-free survival (DFS) and overall survival (OS) were correlated to TRG. Results: Tumor regression was characterized by fibrosis overgrowing on tumor cells, decreased necrosis, and tumor glands (if present) at the periphery of HCRM. With irinotecan/5-fluorouracil (5-FU), major (MjHR), partial (PHR), and no (NHR) histological tumor regression were observed in 17%, 13%, and 70% of patients, respectively. With oxaliplatin/5-FU, MjHR, PHR, and NHR were observed in 37%, 45%, and 18% of patients, respectively. Five patients, treated with oxaliplatin, had complete response in all their metastases. MjHR was associated with an improved 3-year DFS compared with PHR or NHR. MjHR and PHR were associated with an improved 5-year OS compared with NHR. Conclusion: Histological tumor regression of HCRM to chemotherapy corresponds to fibrosis overgrowth and not to increase of necrosis. TRG should be considered when evaluating efficacy of chemotherapy for HCRM. Histological tumor regression was most common among oxaliplatin-treated patients and associated with better clinical outcom

    Severe hepatic sinusoidal obstruction associated with oxaliplatin-based chemotherapy in patients with metastatic colorectal cancer

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    Background: In advanced metastatic colorectal adenocarcinoma, the addition of a neo-adjuvant systemic treatment to surgery might translate into a survival advantage, although this is yet to be confirmed by ongoing randomized trials. The objective of this study was to assess the effects of preoperative systemic chemotherapy on the morphology of non-tumoral liver. Patients and methods: A large series of surgically resected liver metastases (n = 153) was selected. Light microscopy, electron microscopy, and immunohistochemistry using antibodies against endothelial cells (CD31) and hepatic stellate cells (α-SM actin, CRBP-1) were performed to identify sinusoidal wall integrity. Results: We found that 44 (51%) of the 87 post-chemotherapic liver resection specimens had sinusoidal dilatation and hemorrhage, related to rupture of the sinusoidal barrier. In contrast, the 66 livers treated by surgery alone remained normal. In 21 out of the 44 post-chemotherapy patients (48%), perisinusoidal and veno-occlusive fibrosis also developed. Sinusoidal injury persisted several months after end of chemotherapy, and fibrosis may progress. Development of lesions was strongly correlated to the use of oxaliplatin; 34 out of 43 patients (78%) treated with this drug showed striking sinusoidal alterations. Conclusions: Systemic neo-adjuvant chemotherapy in metastatic colorectal cancer frequently causes morphological lesions involving hepatic microvasculature. Sinusoidal obstruction, complicated by perisinusoidal fibrosis and veno-occlusive lesion of the non-tumoral liver revealed by this study, should be included in the list of the adverse side-effects of colorectal systemic chemotherapy, in particular related to the use of oxaliplati

    "Cowboy Cloth" and kinship: The closeness of denim consumption in a south-west Chinese city

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    This article examines the effect of the fabric denim in objectifying kinship in the city of Kunming, China. It is argued that denim has been particularly efficacious due to its ability to insert itself into traditional Chinese kinship notions of nurturance. Parents were seen to gift denim to their children with the object of instigating a change in the lives of the younger generation, coupled with the knowledge that a change in material circumstances would be necessary to achieve such transformation. At the same time, the younger generation's denim also provoked a "kinship gulf" between children and their parents, which parents appeared keen to close by purchasing and wearing denim of their own (although not without a degree of ambivalence, reflected by the presence of inactive jeans in parents' wardrobes). In this remarkable situation denim was seen, firstly, as the tool for creating generational disjuncture through traditional means and subsequently as the prospective solution to overcome this disjuncture. It is argued here that denim moves us to consider the study of kinship as the study of "closeness," a term that affords the consideration of objects in the milieu of intimate social relationships. © 2011 Berg. Printed in the United Kingdom

    Five-Year Follow-Up of a Slowly Resorbable Biosynthetic P4HB Mesh (Phasix) in VHWG Grade 3 Incisional Hernia Repair

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    OBJECTIVE: To assess the 5-year recurrence rate of incisional hernia repair in Ventral Hernia Working Group (VHWG) 3 hernia with a slowly resorbable mesh.SUMMARY BACKGROUND DATA: Incisional hernia recurs frequently after initial repair. In potentially contaminated hernia, recurrences rise to 40%. Recently, the biosynthetic Phasix mesh has been developed that is resorbed in 12-18 months. Resorbable meshes might be a solution for incisional hernia repair to decrease short- and long-term (mesh) complications. However, long-term outcomes after resorption are scarce.METHODS: Patients with VHWG grade 3 incisional midline hernia, who participated in the Phasix trial (Clinilcaltrials.gov: NCT02720042) were included by means of physical examination and computed tomography (CT). Primary outcome was hernia recurrence; secondary outcomes comprised of long-term mesh complications, reoperations, and abdominal wall pain [visual analogue score (VAS): 0-10].RESULTS: In total, 61/84 (72.6%) patients were seen. Median follow-up time was 60.0 [interquartile range (IQR): 55-64] months. CT scan was made in 39 patients (68.4%). A recurrence rate of 15.9% (95% confidence interval: 6.9-24.8) was calculated after 5 years. Four new recurrences (6.6%) were found between 2 and 5 years. Two were asymptomatic. In total, 13/84 recurrences were found. No long-term mesh complications and/or interventions occurred. VAS scores were 0 (IQR: 0-2).CONCLUSIONS: Hernia repair with Phasix mesh in high-risk patients (VHWG 3, body mass index &gt;28) demonstrated a recurrence rate of 15.9%, low pain scores, no mesh-related complications or reoperations for chronic pain between the 2- and 5-year follow-up. Four new recurrences occurred, 2 were asymptomatic. The poly-4-hydroxybutyrate mesh is a safe mesh for hernia repair in VHWG 3 patients, which avoids long-term mesh complications like pain and mesh infection.</p

    AJNR Am J Neuroradiol

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    Accurate quantification of WM lesion load is essential for the care of patients with multiple sclerosis. We tested whether the combination of accelerated 3D-FLAIR and denoising using deep learning-based reconstruction could provide a relevant strategy while shortening the imaging examination. Twenty-eight patients with multiple sclerosis were prospectively examined using 4 implementations of 3D-FLAIR with decreasing scan times (4 minutes 54 seconds, 2 minutes 35 seconds, 1 minute 40 seconds, and 1 minute 15 seconds). Each FLAIR sequence was reconstructed without and with denoising using deep learning-based reconstruction, resulting in 8 FLAIR sequences per patient. Image quality was assessed with the Likert scale, apparent SNR, and contrast-to-noise ratio. Manual and automatic lesion segmentations, performed randomly and blindly, were quantitatively evaluated against ground truth using the absolute volume difference, true-positive rate, positive predictive value, Dice similarity coefficient, Hausdorff distance, and F1 score based on the lesion count. The Wilcoxon signed-rank test and 2-way ANOVA were performed. Both image-quality evaluation and the various metrics showed deterioration when the FLAIR scan time was accelerated. However, denoising using deep learning-based reconstruction significantly improved subjective image quality and quantitative performance metrics, particularly for manual segmentation. Overall, denoising using deep learning-based reconstruction helped to recover contours closer to those from the criterion standard and to capture individual lesions otherwise overlooked. The Dice similarity coefficient was equivalent between the 2-minutes-35-seconds-long FLAIR with denoising using deep learning-based reconstruction and the 4-minutes-54-seconds-long reference FLAIR sequence. Denoising using deep learning-based reconstruction helps to recognize multiple sclerosis lesions buried in the noise of accelerated FLAIR acquisitions, a possibly useful strategy to efficiently shorten the scan time in clinical practice.Translational Research and Advanced Imaging Laborator

    Outcomes of a new slowly resorbable biosynthetic mesh (Phasix (TM)) in potentially contaminated incisional hernias : a prospective, multi-center, single-arm trial

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    Background: Resorbable biomaterials have been developed to reduce the amount of foreign material remaining in the body after hernia repair over the long-term. However, on the short-term, these resorbable materials should render acceptable results with regard to complications, infections, and reoperations to be considered for repair. Additionally, the rate of resorption should not be any faster than collagen deposition and maturation; leading to early hernia recurrence. Therefore, the objective of this study was to collect data on the short-term performance of a new resorbable biosynthetic mesh (Phasix (TM)) in patients requiring Ventral Hernia Working Group (VHWG) Grade 3 midline incisional hernia repair. Materials and methods: A prospective, multi-center, single-arm trial was conducted at surgical departments in 15 hospitals across Europe. Patients aged >= 18, scheduled to undergo elective Ventral Hernia Working Group Grade 3 hernia repair of a hernia larger than 10 cm(2) were included. Hernia repair was performed with Phasix (TM) Mesh in sublay position when achievable. The primary outcome was the rate of surgical site occurrence (SSO), including infections, that required intervention until 3 months after repair. Results: In total, 84 patients were treated with Phasix (TM) Mesh. Twenty-two patients (26.2%) developed 32 surgical site occurrences. These included 11 surgical site infections, 9 wound dehiscences, 7 seromas, 2 hematomas, 2 skin necroses, and 1 fistula. No significant differences in surgical site occurrence development were found between groups repaired with or without component separation technique, and between clean-contaminated or contaminated wound sites. At three months, there were no hernia recurrences. Conclusion: Phasix (TM) Mesh demonstrated acceptable postoperative surgical site occurrence rates in patients with a Ventral Hernia Working Group Grade 3 hernia. Longer follow-up is needed to evaluate the recurrence rate and the effects on quality of life. This study is ongoing through 24 months of follow-up
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