We present a modification of a recently developed volume of fluid method for multiphase problems (Ii et al. in J Comput Phys 231(5):2328–2358,
2012
), so that it can be used in conjunction with a ...fractional-step method and fast Poisson solver, and validate it with standard benchmark problems. We then consider emulsions of two-fluid systems and study their rheology in a plane Couette flow in the limit of vanishing inertia. We examine the dependency of the effective viscosity
μ
on the volume fraction
Φ
(from 10 to
30
%
) and the Capillary number
Ca
(from 0.1 to 0.4) for the case of density and viscosity ratio 1. We show that the effective viscosity decreases with the deformation and the applied shear (shear-thinning) while exhibiting a non-monotonic behavior with respect to the volume fraction. We report the appearance of a maximum in the effective viscosity curve and compare the results with those of suspensions of rigid and deformable particles and capsules. We show that the flow in the solvent is mostly a shear flow, while it is mostly rotational in the suspended phase; moreover, this behavior tends to reverse as the volume fraction increases. Finally, we evaluate the contributions to the total shear stress of the viscous stresses in the two fluids and of the interfacial force between them.
HMGB1 as biomarker and drug target Venereau, Emilie; De Leo, Federica; Mezzapelle, Rosanna ...
Pharmacological research,
September 2016, 2016-Sep, 2016-09-00, 20160901, Letnik:
111
Journal Article
Recenzirano
Display omitted
High Mobility Group Box 1 protein was discovered as a nuclear protein, but it has a ⿿second life⿿ outside the cell where it acts as a damage-associated molecular pattern. HMGB1 is ...passively released or actively secreted in a number of diseases, including trauma, chronic inflammatory disorders, autoimmune diseases and cancer. Extracellular HMGB1 triggers and sustains the inflammatory response by inducing cytokine release and by recruiting leucocytes. These characteristics make extracellular HMGB1 a key molecular target in multiple diseases. A number of strategies have been used to prevent HMGB1 release or to inhibit its activities. Current pharmacological strategies include antibodies, peptides, decoy receptors and small molecules. Noteworthy, salicylic acid, a metabolite of aspirin, has been recently found to inhibit HMGB1. HMGB1 undergoes extensive post-translational modifications, in particular acetylation and oxidation, which modulate its functions. Notably, high levels of serum HMGB1, in particular of the hyper-acetylated and disulfide isoforms, are sensitive disease biomarkers and are associated with different disease stages. In the future, the development of isoform-specific HMGB1 inhibitors may potentiate and fine-tune the pharmacological control of inflammation. We review here the current therapeutic strategies targeting HMGB1, in particular the emerging and relatively unexplored small molecules-based approach.
Tissue damage causes inflammation, by recruiting leukocytes and activating them to release proinflammatory mediators. We show that high-mobility group box 1 protein (HMGB1) orchestrates both ...processes by switching among mutually exclusive redox states. Reduced cysteines make HMGB1 a chemoattractant, whereas a disulfide bond makes it a proinflammatory cytokine and further cysteine oxidation to sulfonates by reactive oxygen species abrogates both activities. We show that leukocyte recruitment and activation can be separated. A nonoxidizable HMGB1 mutant in which serines replace all cysteines (3S-HMGB1) does not promote cytokine production, but is more effective than wild-type HMGB1 in recruiting leukocytes in vivo. BoxA, a HMGB1 inhibitor, interferes with leukocyte recruitment but not with activation. We detected the different redox forms of HMGB1 ex vivo within injured muscle. HMGB1 is completely reduced at first and disulfide-bonded later. Thus, HMGB1 orchestrates both key events in sterile inflammation, leukocyte recruitment and their induction to secrete inflammatory cytokines, by adopting mutually exclusive redox states.
Several transcription factors (TFs) oscillate, periodically relocating between the cytoplasm and the nucleus. NF-κB, which plays key roles in inflammation and cancer, displays oscillations whose ...biological advantage remains unclear. Recent work indicated that NF-κB displays sustained oscillations that can be entrained, that is, reach a persistent synchronized state through small periodic perturbations. We show here that for our GFP-p65 knock-in cells NF-κB behaves as a damped oscillator able to synchronize to a variety of periodic external perturbations with no memory. We imposed synchronous dynamics to prove that transcription of NF-κB-controlled genes also oscillates, but mature transcript levels follow three distinct patterns. Two sets of transcripts accumulate fast or slowly, respectively. Another set, comprising chemokine and chemokine receptor mRNAs, oscillates and resets at each new stimulus, with no memory of the past. We propose that TF oscillatory dynamics is a means of segmenting time to provide renewing opportunity windows for decision.
Colorectal cancer is diagnosed progressively in employed patients due to screening programs and increasing retirement age. The objective of this study was to identify prognostic factors for return to ...work and work disability in patients with colorectal cancer.
The research protocol was published at PROSPERO with registration number CRD42017049757. A systematic review of cohort and case-control studies in colorectal cancer patients above 18 years, who were employed when diagnosed, and who had a surgical resection with curative intent were included. The primary outcome was return to work or work disability. Potentially prognostic factors were included in the analysis if they were measured in at least three studies. Risk of bias was assessed according to the QUality In Prognosis Studies tool. A qualitative synthesis analysis was performed due to heterogeneity between studies. Quality of evidence was evaluated according to Grading of Recommendation Assessment, Development and Evaluation.
Eight studies were included with a follow-up period of 26 up to 520 weeks. (Neo)adjuvant therapy, higher age, and more comorbidities had a significant negative influence on return to work. A previous period of unemployment, extensive surgical resection and postoperative complications significantly increased the risk of work disability. The quality of evidence for these prognostic factors was considered very low to moderate.
Health care professionals need to be aware of these prognostic factors to select patients eligible for timely intensified rehabilitation in order to optimize the return to work process and prevent work disability.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Autoantibodies against double-stranded DNA (dsDNA) and nucleosomes represent a hallmark of systemic lupus erythematosus (SLE). However, the mechanisms involved in breaking the immunological tolerance ...against these poorly immunogenic nuclear components are not fully understood. Impaired phagocytosis of apoptotic cells with consecutive release of nuclear antigens may contribute to the immune pathogenesis. The architectural chromosomal protein and proinflammatory mediator high mobility group box protein 1 (HMGB1) is tightly attached to the chromatin of apoptotic cells. We demonstrate that HMGB1 remains bound to nucleosomes released from late apoptotic cells in vitro. HMGB1-nucleosome complexes were also detected in plasma from SLE patients. HMGB1-containing nucleosomes from apoptotic cells induced secretion of interleukin (IL) 1beta, IL-6, IL-10, and tumor necrosis factor (TNF) alpha and expression of costimulatory molecules in macrophages and dendritic cells (DC), respectively. Neither HMGB1-free nucleosomes from viable cells nor nucleosomes from apoptotic cells lacking HMGB1 induced cytokine production or DC activation. HMGB1-containing nucleosomes from apoptotic cells induced anti-dsDNA and antihistone IgG responses in a Toll-like receptor (TLR) 2-dependent manner, whereas nucleosomes from living cells did not. In conclusion, HMGB1-nucleosome complexes activate antigen presenting cells and, thereby, may crucially contribute to the pathogenesis of SLE via breaking the immunological tolerance against nucleosomes/dsDNA.
A partir de un modelo paramétrico para procesos de primer orden más tiempo muerto, se desarrollan ecuaciones de sintonía para controladores PID. Se usa como criterio de optimización la minimización ...de una función objetivo, compuesta por una combinación de la integral del valor absoluto del error (IAE) y la varianza de la señal del controlador. Se obtienen dos conjuntos de ecuaciones de sintonía, uno para 0.1 <t.sub.0/tau<1.5 y otro para 1.5<t.sub.0/tau<5.0. Ambos conjuntos de ecuaciones de sintonía se evalúan con procesos de referencia, y sus resultados se comparan con las sintonías de mínimo IAE, integral cuadrada del error (ISE), integral cuadrada del error por el tiempo (ISTE), por control de modelo interno (IMC) y Lambda (x). A diferencia de las ecuaciones tradicionales, las propuestas en este trabajo consideran la respuesta de la variable controlada y la variabilidad en la señal que se envía a los actuadores.
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