Noncommutative generalization of SU(n)-principal fiber bundles: a review

This is an extended version of a communication made at the international conference ``Noncommutative Geometry and Physics'' held at Orsay in april 2007. In this proceeding, we make a review of some noncommutative constructions connected to the ordinary fiber bundle theory. The noncommutative algebra is the endomorphism algebra of a SU(n)-vector bundle, and its differential calculus is based on its Lie algebra of derivations. It is shown that this noncommutative geometry contains some of the most important constructions introduced and used in the theory of connections on vector bundles, in particular, what is needed to introduce gauge models in physics, and it also contains naturally the essential aspects of the Higgs fields and its associated mechanics of mass generation. It permits one also to extend some previous constructions, as for instance symmetric reduction of (here noncommutative) connections. From a mathematical point of view, these geometrico-algebraic considerations highlight some new point on view, in particular we introduce a new construction of the Chern characteristic classes

Early stages of crystallization in gel derived ZrO2 precursors

International audienc

Morbidity and long-term results of subcutaneous pyelovesical bypass in chronic ureteral obstruction

International audienc

Profil et environnement immunitaires des tumeurs de la voie excrétrice supérieure

International audienc

Bladder Recurrence Following Upper Tract Surgery for Urothelial Carcinoma: A Contemporary Review of Risk Factors and Management Strategies

Context: Bladder recurrences have been reported in 22–47% of patients after surgery for upper urinary tract urothelial carcinoma (UTUC). This collaborative review focuses on risk factors for and treatment strategies to reduce bladder recurrences after upper tract surgery for UTUC. Objective: To review the current evidence on risk factors and treatment strategies for intravesical recurrence (IVR) after upper tract surgery for UTUC. Evidence acquisition: This collaborative review is based on a literature search of PubMed/Medline, Embase, Cochrane Library, and currently available guidelines on UTUC. Relevant papers on bladder recurrence (etiology, risk factors, and management) after upper tract surgery were selected. Special attention has been paid to (1) the genetic background of bladder recurrences, (2) bladder recurrences after ureterorenoscopy (URS) with or without a biopsy, and (3) postoperative or adjuvant intravesical instillations. The literature search was performed in September 2022. Evidence synthesis: Recent evidence supports the hypothesis that bladder recurrences after upper tract surgery for UTUC are often clonally related. Clinicopathologic risk factors (patient, tumor, and treatment related) have been identified for bladder recurrences after UTUC diagnosis. Specifically, the use of diagnostic ureteroscopy before radical nephroureterectomy (RNU) is associated with an increased risk of bladder recurrences. Further, a recent retrospective study suggests that performing a biopsy during ureteroscopy may further worsen IVR (no URS: 15.0%; URS without biopsy: 18.4%; URS with biopsy: 21.9%). Meanwhile, a single postoperative instillation of intravesical chemotherapy has been shown to be associated with a reduced bladder recurrence risk after RNU compared with no instillation (hazard ratio 0.51, 95% confidence interval 0.32–0.82). Currently, there are no data on the value of a single postoperative intravesical instillation after ureteroscopy. Conclusions: Although based on limited retrospective data, performing URS seems to be associated with a higher risk of bladder recurrences. Future studies are warranted to assess the influence of other surgical factors as well as the role of URS biopsy or immediate postoperative intravesical chemotherapy after URS for UTUC. Patient summary: In this paper, we review recent findings on bladder recurrences after upper tract surgery for upper urinary tract urothelial carcinoma