Birkhoff strata of the Grassmannian Gr(2)\mathrm{^{(2)}}: Algebraic curves

Algebraic varieties and curves arising in Birkhoff strata of the Sato Grassmannian Gr${^{(2)}}$ are studied. It is shown that the big cell $\Sigma_0$ contains the tower of families of the normal rational curves of all odd orders. Strata $\Sigma_{2n}$, $n=1,2,3,...$ contain hyperelliptic curves of genus $n$ and their coordinate rings. Strata $\Sigma_{2n+1}$, $n=0,1,2,3,...$ contain $(2m+1,2m+3)-$plane curves for $n=2m,2m-1$ $(m \geq 2)$ and $(3,4)$ and $(3,5)$ curves in $\Sigma_3$, $\Sigma_5$ respectively. Curves in the strata $\Sigma_{2n+1}$ have zero genus.Comment: 14 pages, no figures, improved some definitions, typos correcte

Nationwide analysis of open groin hernia repairs in Italy from 2015 to 2020

Introduction: Inguinal hernia repair is one of the most commonly performed operations in general surgery. A total of 130.000 inguinal hernia repairs are performed yearly in Italy, and approximately 20 million inguinal hernias are treated worldwide annually. This report represents the trend analysis in inguinal hernia repair in Italy from a nationwide dataset for the 6-year period from 2015 to 2020. Materials and methods: Based on regional hospital discharge records, all the inguinal hernia repairs performed in public and private hospitals in Italy between 2015 and 2020 were reviewed based on diagnosis and procedure codes. For the aim of this study, data from the AgeNas (The National Agency for Regional Health Services) data source were analyzed. Results: Elective inguinal hernia repairs outnumbered urgent operations over the 6-year study period, ranging from 122,737 operations in 2015 to 65,780 in 2020 as absolute numbers, and from 87.96 to 83.3% of total procedures in 2019 and 2020 respectively, with an annual change ranging from - 66.58%, between 2020 and 2019, to - 2.49%, between 2019 and 2018 (mean = - 18.74%; CI =- 46.7%-9.22%; p < 0.0001). Conclusions: This large-scale review of groin hernia data from a nationwide Italian dataset provides a unique opportunity to obtain a snapshot of open groin hernia repair activity. More specifically, there is a trend to perform more elective than urgent procedures and there is a steady decrease in the amount of open hernia repairs in favor to laparoscopy

Cancer risk in adrenalectomy: are adrenal lesions equal or more than 4 cm a contraindication for laparoscopy?

none7openBalla A, Corallino D, Ortenzi M, Palmieri L, Meoli F, Guerrieri M, Paganini AMBalla, A; Corallino, D; Ortenzi, M; Palmieri, L; Meoli, F; Guerrieri, M; Paganini, A

Is transperitoneal laparoscopic adrenalectomy for pheochromocytoma really more challenging? A propensity score-matched analysis

Purpose Minimally invasive surgery is the gold standard treatment for adrenal masses, but it may be a challenging procedure in the case of pheochromocytoma (PHEO). The aim of the present study is to report the results of transperitoneal laparoscopic adrenalectomy (TLA) in cases of PHEO in comparison to other types of adrenal lesions. Methods From 1994 to 2021, 629 patients underwent adrenalectomy. Twenty-two and thirty-five patients, respectively, were excluded because they underwent bilateral and open adrenalectomy, leaving 572 patients for inclusion. Of these, 114 patients had PHEO (Group A), and 458 had other types of lesions (Group B). To adjust for potential baseline confounders, a propensity score matching (PSM) analysis was conducted. Results After PSM, 114 matched pairs of patients were identified from each group. Statistically significant differences were not observed when comparing the median operative time (85 and 90 min in Groups A and B, respectively, p = 0.627), conversion rate [6 (5.3%) in each group, p = 1.000], transfusion rate [4 (3.5%) and 3 (2.6%) in Groups A and B, respectively, p = 1.000], complication rate [7 (6.1%) and 9 (7.9%) in Groups A and B, respectively, p = 0.796), median postoperative hospital stay (3.9 and 3.6 days in Groups A and B, respectively, p = 0.110), and mortality rate [1 (0.9%) in each group, p = 1.000]. Conclusions Based on this analysis, the results of TLA for PHEO are equivalent to those of TLA for other types of adrenal lesions, but the fundamental requirements are multidisciplinary patient management and adequate surgeon experience. Further prospective studies are required to draw definitive conclusions

Universal features of cell polarization processes

Cell polarization plays a central role in the development of complex organisms. It has been recently shown that cell polarization may follow from the proximity to a phase separation instability in a bistable network of chemical reactions. An example which has been thoroughly studied is the formation of signaling domains during eukaryotic chemotaxis. In this case, the process of domain growth may be described by the use of a constrained time-dependent Landau-Ginzburg equation, admitting scale-invariant solutions {\textit{\`a la}} Lifshitz and Slyozov. The constraint results here from a mechanism of fast cycling of molecules between a cytosolic, inactive state and a membrane-bound, active state, which dynamically tunes the chemical potential for membrane binding to a value corresponding to the coexistence of different phases on the cell membrane. We provide here a universal description of this process both in the presence and absence of a gradient in the external activation field. Universal power laws are derived for the time needed for the cell to polarize in a chemotactic gradient, and for the value of the smallest detectable gradient. We also describe a concrete realization of our scheme based on the analysis of available biochemical and biophysical data.Comment: Submitted to Journal of Statistical Mechanics -Theory and Experiment

Preliminary data related to the effect of climacostol produced by the freshwater ciliate climacostomum virens on human adenovirus

The new epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. Owing to the side effects of chemical disinfectants, there is an increasing need for knowledge on the use of virucidal compounds, especially those of a natural origin. Climacostol is a molecule produced by a freshwater ciliate and it exhibits activity against bacterial and fungal pathogens. We thus also speculated that there might be an effect on viral viability, which has never been tested. To evaluate such activity, we chose human adenovirus (HAdV), which is representative of waterborne viruses. We conducted experiments using HAdV serotype 5, whose titer was determined by infecting HeLa cell cultures. HAdV5 was shown to be sensitive to climacostol at a concentration of 0.0002 mg/mL, with an approximate 3 Log10 reduction when the initial titer of HAdV5 was approximately 104 and 103 TCID50/mL. These preliminary results could be an important starting point for further research aimed at improving the characterization of climacostol activity under different experimental conditions and against various viruses, including enveloped ones (i.e., the coronavirus). The production of climacostol by a protist living in fresh water also suggests a possible application in the activated sludge of wastewater treatment plants

Coisotropic deformations of algebraic varieties and integrable systems

Coisotropic deformations of algebraic varieties are defined as those for which an ideal of the deformed variety is a Poisson ideal. It is shown that coisotropic deformations of sets of intersection points of plane quadrics, cubics and space algebraic curves are governed, in particular, by the dKP, WDVV, dVN, d2DTL equations and other integrable hydrodynamical type systems. Particular attention is paid to the study of two- and three-dimensional deformations of elliptic curves. Problem of an appropriate choice of Poisson structure is discussed.Comment: 17 pages, no figure