Effective interactions between parallel-spin electrons in two-dimensional jellium approaching the magnetic phase transition

We evaluate the effective interactions in a fluid of electrons moving in a plane, on the approach to the quantum phase transition from the paramagnetic to the fully spin-polarized phase that has been reported from Quantum Monte Carlo runs. We use the approach of Kukkonen and Overhauser to treat exchange and correlations under close constraints imposed by sum rules. We show that, as the paramagnetic fluid approaches the phase transition, the effective interactions at low momenta develop an attractive region between parallel-spin electrons and a corresponding repulsive region for antiparallel-spin electron pairs. A connection with the Hubbard model is made and used to estimate the magnetic energy gap and hence the temperature at which the phase transition may become observable with varying electron density in a semiconductor quantum well.Comment: 11 pages, 3 figure

Ligand-independent oligomerization of TACI is controlled by the transmembrane domain and regulates proliferation of activated B cells.

In mature B cells, TACI controls class-switch recombination and differentiation into plasma cells during T cell-independent antibody responses. TACI binds the ligands BAFF and APRIL. Approximately 10% of patients with common variable immunodeficiency (CVID) carry TACI mutations, of which A181E and C172Y are in the transmembrane domain. Residues A181 and C172 are located on distinct sides of the transmembrane helix, which is predicted by molecular modeling to spontaneously assemble into trimers and dimers. In human B cells, these mutations impair ligand-dependent (C172Y) and -independent (A181E) TACI multimerization and signaling, as well as TACI-enhanced proliferation and/or IgA production. Genetic inactivation of TACI in primary human B cells impaired survival of CpG-activated cells in the absence of ligand. These results identify the transmembrane region of TACI as an active interface for TACI multimerization in signal transduction, in particular for ligand-independent signals. These functions are perturbed by CVID-associated mutations

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018.

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

High-Lard and High-Fish Oil Diets Differ in Their Effects on Insulin Resistance Development, Mitochondrial Morphology and Dynamic Behaviour in Rat Skeletal Muscle

Fish oil (mainly omega 3 polyunsaturated fatty acids), differently from lard (mainly saturated fatty acids) has been sug- gested to have anti-inflammatory effects associated with amelioration of insulin sensibility. An important role in skele- tal muscle insulin resistance development has been recently attributed to mitochondrial dynamic behavior. Mitochon- dria are dynamic organelles that frequently undergo fission/fusion processes and a shift toward fission process has been associated with skeletal muscle mitochondrial dysfunction and insulin resistance development. The present work aimed to evaluate if the replacement of lard with fish oil in high-fat diet positively affect skeletal muscle mitochondrial dy- namic behavior in association with the improvement of insulin-resistance. Body weight gain, systemic insulin-resistance (glucose/insulin ratio), serum TNFα levels and skeletal muscle lipid content were assessed in rats fed a high-lard or high-fish-oil diet for 6 weeks. In skeletal muscle sections, immunohistochemical analysis were performed to detect the presence of insulin receptor substrate 1 (IRS1) and tyrosine phosphorylated IRS1 (key factor in insulin signalling path- way) as well as to detect the main proteins involved in mitochondrial fusion (MFN2 and OPA1) and fission (DRP1 and Fis1) processes. Skeletal muscle mitochondrial ultrastructural features were assessed by electron microscopy. High-fish oil feeding induced lower body weight gain, systemic inflammation and insulin-resistance development as well as skeletal muscle lipid accumulation compared to high-lard feeding. Skeletal muscle sections from high-fish oil fed rats exhibited a greater number of immunoreactive fibers for MFN2 and OPA1 proteins as well as weaker immunostaining for DRP1 and Fis1 compared to sections from high-lard fed rats. Electron microscopy observations suggested a promi- nent presence of fission events in L rats and fusion events in F rats. The positive effect of the replacement of lard with fish oil in high-fat diet on systemic and skeletal muscle insulin sensibility was associated to changes in mitochondrial dynamic behavior

p50 nuclear factor-kappaB overexpression in tumor-associated macrophages inhibits M1 inflammatory responses and antitumor resistance

Tumor-associated macrophages (TAM) are a major inflammatory infiltrate in tumors and a major component of the protumor function of inflammation. TAM in established tumors generally have an M2 phenotype with defective production of interleukin-12 (IL-12) and high IL-10. Here, we report that defective responsiveness of TAM from a murine fibrosarcoma and human ovarian carcinoma to M1 activation signals was associated with a massive nuclear localization of the p50 nuclear factor-kappaB (NF-kappaB) inhibitory homodimer. p50 overexpression inhibited IL-12 expression in normal macrophages. TAM isolated from p50(-/-) mice showed normal production of M1 cytokines, associated with reduced growth of transplanted tumors. Bone marrow chimeras showed that p50 inactivation in hematopoietic cells was sufficient to result in reduced tumor growth. Thus, p50 NF-kappaB overexpression accounts for the inability of TAM to mount an effective M1 antitumor response capable of inhibiting tumor growth

La responsabilità sanitaria tra prospettiva interna e comparata

Un'indagine, anche comparativa, sulle molteplici problematiche poste dal nuovo sistema della responsabilità sanitaria, a sei anni dall'entrata in vigore della legge n. 24 del 2017 (c.d. Gelli-Bianco