Compact radio emission indicates a structured jet was produced by a binary neutron star merger.

The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High-spatial-resolution measurements of the source size and displacement can discriminate between these scenarios. We present very-long-baseline interferometry observations, performed 207.4 days after the merger by using a global network of 32 radio telescopes. The apparent source size is constrained to be smaller than 2.5 milli-arc seconds at the 90% confidence level. This excludes the isotropic outflow scenario, which would have produced a larger apparent size, indicating that GW170817 produced a structured relativistic jet. Our rate calculations show that at least 10% of neutron star mergers produce such a jet.

Self-Induced Faraday Instability Laser.

We predict the onset of self-induced parametric or Faraday instabilities in a laser, spontaneously caused by the presence of pump depletion, which leads to a periodic gain landscape for light propagating in the cavity. As a result of the instability, continuous wave oscillation becomes unstable even in the normal dispersion regime of the cavity, and a periodic train of pulses with ultrahigh repetition rate is generated. Application to the case of Raman fiber lasers is described, in good quantitative agreement between our conceptual analysis and numerical modeling.

Linear and Nonlinear Bullets of the Bogoliubov-de Gennes Excitations.

We report on the focalization of Bogoliubov-de Gennes excitations of the nonlinear Schrödinger equation in the defocusing regime (Gross-Pitaevskii equation for repulsive Bose-Einstein condensates) with a spatially modulated periodic potential. Exploiting the modification of the dispersion relation induced by the modulation, we demonstrate the existence of localized structures of the Bogoliubov-de Gennes excitations, in both the linear and nonlinear regimes (linear and nonlinear "bullets"). These traveling Bogoliubov-de Gennes bullets, localized both spatially and temporally in the comoving reference frame, are robust and propagate remaining stable, without spreading or filamentation. The phenomena reported in this Letter could be observed in atomic Bose-Einstein condensates in the presence of a spatially periodic potential induced by an optical lattice.

Pattern Generation by Dissipative Parametric Instability.

Nonlinear instabilities are responsible for spontaneous pattern formation in a vast number of natural and engineered systems, ranging from biology to galaxy buildup. We propose a new instability mechanism leading to pattern formation in spatially extended nonlinear systems, which is based on a periodic antiphase modulation of spectrally dependent losses arranged in a zigzag way: an effective filtering is imposed at symmetrically located wave numbers k and -k in alternating order. The properties of the dissipative parametric instability differ from the features of both key classical concepts of modulation instabilities, i.e., the Benjamin-Feir instability and the Faraday instabiltyity. We demonstrate how the dissipative parametric instability can lead to the formation of stable patterns in one- and two-dimensional systems. The proposed instability mechanism is generic and can naturally occur or can be implemented in various physical systems.

[Sustained low-efficiency dialysis in acute renal failure]. / Terapie sostitutive renali intermittenti prolungate (SLED/EED) nell'insufficienza renale acuta in terapia intensiva.

Renal replacement therapies (RRT) are a key component of the therapeutic approach to acute renal failure (ARF) in the intensive care unit (ICU), and they are usually performed as classic Intermittent (intermittent hemodialysis) or continuous RRT (such as for example continuous venovenous hemofiltration, CVVH). No clear evidence exists on what the first-choice RRT option should be for ICU patients with ARF. Alternative strategies have been developed, under the form of intermittent prolonged RRT, with the aim of providing easy to perform, highly efficient, and less expensive RRT in the ICU. In this review we put forward the hypothesis that hybrid RRT, such as sustained low-efficiency dialysis ( sLED), could offer a valuable alternative to the currently available strategies in the critically ill with ARF.

[Polymyxin-B direct hemoperfusion (PMX-DHP) in gram negative sepsis]. / L'moperfusione diretta con Polimixina-B (PMX-DHP) nel trattamento della sepsi da gram negativi.

UNLABELLED: Severe sepsis and septic shock have a mortality rate that may range between 28 and 50%. It is estimated that approximately 200,000 patients die per annum in the USA as a consequence of sepsis. The reduction of plasma endotoxin levels to achieve a favourable outcome for septic patients has been previously demonstrated but the effectiveness of treatments targeting single inflammatory mediators during established sepsis has been disappointing. Furthermore,some clinical study clinically showed valuable reduction in cytokine levels by hemofiltration alone. The prompt removal of endotoxins could be an effective way to reduce the immunological activation and the amount of NO produced by endotoxin-activated inducible NO-synthase in many tissues and cells. The polymyxin B cartridge is an extracorporeal hemoperfusion device (PMX-DHP) known to remove circulating endotoxins. Open-label clinical trials testing PMX-DHP have demonstrated its safety in the septic shock treatment while the overall survival rate significantly improved in comparison with the control groups. The purpose of this study was to investigate the effects of PMX-DHP on redox status, inflammatory cytokine profile, monocytes and PMN leukocyte activation in Gram-negative sepsis. Prospective study: six patients, 2 males and 4 females 60.5+/-24.5 years old, in ICU for severe Gram-negative sepsis (emergency surgery for intra abdominal infection). Two PMX-DHP runs, at T0 and T1; 2 hours each; the first within 24 hours from sepsis diagnosis or 12 hours after emergency surgery, the first PMX-DHP at T0, the second after 24 hours.; APACHE II score at T0: 20.1+/-3.7; SOFA score 14.2+/-2.5; organ failure: 3+/-1.5; norepinephrine(Ne) in 1 patient; Ne + dopamine (DA) in 4 patients; DA in 1 patient only. Mean dosage: Ne 0.24 mcg/kg/min; DA 8.9 mcg/kg/min. Four patients in CRRT (continuous veno-venous hemofiltration, AN69 hemofilter) for the entire length of the study. QB 100+/-10 ml/min. Pre and post PMX-DHP, plasma endotoxins as well as anti-IL 1-beta, IL2, IL4, IL5, IL6, IL8, IL10, TNF-alpha, GM-CSF, IFN-gamma levels were measured. Expression of CD64 on monocytes and PMN leukocytes and I -2r CD25 on CD4+ T cells by flow cytometry. Total and reduced plasma cysteine, homocysteine, glutathione (GSH); plasma glutathione peroxidase (GSH-Px) and reductase (GSH-Rx); erythrocyte GSH (eGSH), eGSH-Px and eGSH-Rx; NADP and NADPH and their ratio assessed pre and post PMX-DHP, all compared with 15 age and gender-matched healthy subjects for complete REDOX characterization. RESULTS: We observed a significant reduction of endotoxin levels post PMX-DHP; CD64 monocytes and PMN leukocytes overexpression returned to normal; pro-inflammatory cytokines Il6, Il 10 and TNF-alpha were significantly reduced. We detected no differences in plasma levels of anti-IL 1-beta, IL2, IL4, IL5, IL8, GM-CSF, IFN-gamma pre versus post PMX-DHP. SOFA score from 14.2+/-2.5 to 8.9+/-2.1 post PMX-DHP runs. Four out of six patients survived and were discharged; mortality was 33% versus the anticipated 51%. CONCLUSION: PMX-DHP reduces circulating endotoxins, down-activates monocytes and PMN leukocytes, reduces pro-Inflammatory cytokines and corrects the redox environment imbalance preventing oxidative damage to endothelial cells and the metabolic and functional microvascular derangements that usually lead to multi-organ failure and septic shock.

[Sepsis: from pathophysiology to treatment]. / La sepsi: dalla patogenesi al trattamento.

Severe sepsis and septic shock are still associated with high mortality rates. To improve the outcome, multidisciplinary interactions and cooperation between basic, clinical and industrial researchers are mandatory to develop new artificial or biological devices for the treatment of septic syndrome and related systemic complications. In the future, the development and validation of new biomarkers, aimed at an early diagnosis of sepsis, and the rigorous monitoring of the most significant prognostic indicators, could contribute to better understanding of the mechanisms underlying septic syndrome as well as to the timely institution of potentially effective treatments.

Effect of n-3 polyunsaturated fatty acids on cyclosporine pharmacokinetics in kidney graft recipients: a randomized placebo-controlled study.

Highly concentrated marine polyunsaturated fatty acids (n-3 PUFA), affecting the lipids and lipophilic drugs metabolism, can interfere with cyclosporine (CyA) pharmacokinetics. This prospective, randomized and placebo-controlled, double-blind study involved 42 kidney graft recipients. From day +1, 21 pts (E) received 6 g n-3 PUFA (85% EPA + DHA, Esapent, Pharmacia) and 21 pts (P) received placebo (olive oil), both reduced to 3 g from day +30 on. A quadruple immunosuppressive regimen was employed. Plasma creatinine, lipids and CyA pharmacokinetics were investigated 1, 3, 6, 9 and 12 months after graft. The two groups were comparable for age, weight, M/F ratio, hypertension prevalence and baseline lipids. Active treatment did not affect total and HDL-cholesterol, but significantly lowered triglycerides (E:120 +/- 12 vs P:166 +/- 21 mg/dl, p < 0.0001). At one year, E pts had lower creatinine than P (1.26 +/- 0.06 vs. 1.88 +/- 0.2 mg/dl, p < 0.05), comparable CyA dosage, and a larger CyA area under the curve (AUC) (n.s.), with a higher blood peak level (Cmax) (p < 0.04) and less variance in time to peak (n.s.). The larger AUC in the E group at all intervals and the better pattern of plasma creatinine, with no rise in blood pressure, provided evidence of better CyA absorption and metabolism in n-3 PUFA supplemented kidney graft recipients.

High-flux acetate haemodialysis: a single-centre experience.

One hundred haemodialysed patients have been treated for 4 h thrice weekly by acetate haemodialysis with high-flux dialysers (HAHD) 1.4-1.8 m2 and automated ultrafiltration control for 18.9 +/- 8.3 months. The aim of the study was to evaluate the efficacy of treatment as regards urea and beta 2-microglobulin removal, cardiovascular stability, acid-base balance and plasma Il-1 variations. Moreover medium-term observation of both lipid profile and basal beta 2-microglobulin concentrations were performed. With our current adequacy criteria (urea clearance greater than or equal to 120 l/week; KT/V greater than or equal to 1.2; beta 2-microglobulin removal greater than or equal to 150 mg/treatment), the occurrence of hypotension was 6% during 24,500 treatments. Cardiovascular stability was preserved by the increase of total peripheral resistances in response to cardiac output decrease. No disturbances of acid-base parameters were observed in spite of plasma acetate concentrations greater than 6 mmol/l. No variations of plasma Il-1 occurred during the session or 2 h later.

Natural killer activity and antibody-dependent cellular cytotoxicity in progressive systemic sclerosis.

Enhanced natural killer (NK) activity and normal lymphocyte antibody-dependent cellular cytotoxicity (ADCC) were observed in 16 patients with a diagnosis of progressive systemic sclerosis (PSS). Higher NK activity levels were observed against NK-sensitive K562 target cells, while the NK-resistant P815, Daudi and Raji cell lines were not lysed. Cytofluorimetric studies and morphological analysis of peripheral blood lymphocytes (PBL) showed an increased number of CD16 positive cells and large granular lymphocytes (LGL), indicating that the enhancement observed was probably attributable to an increase in the number of circulating NK cells.

Erythrocyte ferritin in patients on chronic hemodialysis treatment.

Serum ferritin (SF) and erythrocyte ferritin (EF) were evaluated in 35 patients on chronic hemodialysis treatment (CHD), in 45 healthy subjects and in 22 nonnephropathic females with iron deficiency anemia. Twenty-five CHD patients with basal SF less than 500 micrograms/l were treated orally with 200 mg of Fe2+ for 2 months and the positive (hemoglobin increase greater than 1 g/dl) or negative response to the therapy was correlated to the basal levels of SF and EF. Three groups of CHD patients could be defined on the basis of their basal SF levels (hypo-, normo- or hyperferritinemic). Nine patients with increased SF levels had also EF levels significantly higher than the other CHD patients and controls since they were probably iron-overloaded. In the other 2 groups of CHD patients, EF levels were significantly higher than in controls for each level of SF probably because of the reduced utilization of iron by uremic bone marrow. Among the 25 treated CHD patients, only 5 responded to the therapy: 3 were hypoferritinemic while the other 2 responders had basal SF within the normal range. Four hypoferritinemic patients did not respond to the therapy. Four out of five responders had the lowest EF levels among CHD patients. EF measurement could be an important and useful test in detecting the presence of an iron deficiency erythropoiesis in CHD patients.