Blazars are the most extreme active galactic nuclei. They possess oppositely directed plasma jets emanating at near light speeds from accreting supermassive black holes. According to theoretical ...models, such jets are propelled by magnetic fields twisted by differential rotation of the black hole's accretion disk or inertial-frame-dragging ergosphere. The flow velocity increases outward along the jet in an acceleration and collimation zone containing a coiled magnetic field. Detailed observations of outbursts of electromagnetic radiation, for which blazars are famous, can potentially probe the zone. It has hitherto not been possible to either specify the location of the outbursts or verify the general picture of jet formation. Here we report sequences of high-resolution radio images and optical polarization measurements of the blazar BL Lacertae. The data reveal a bright feature in the jet that causes a double flare of radiation from optical frequencies to TeV gamma-ray energies, as well as a delayed outburst at radio wavelengths. We conclude that the event starts in a region with a helical magnetic field that we identify with the acceleration and collimation zone predicted by the theories. The feature brightens again when it crosses a standing shock wave corresponding to the bright 'core' seen on the images.
Non-alcoholic fatty liver disease (NAFLD) is currently the fastest growing indication to liver transplantation (LT) in Western Countries, both for end stage liver disease and hepatocellular ...carcinoma. NAFLD/non-alcoholic steatohepatitis (NASH) is often expression of a systemic metabolic syndrome; therefore, NAFLD/NASH patients require a multidisciplinary approach for a proper pre-surgical evaluation, which is important to achieve a post-transplant outcome comparable to that of other indications to LT. NAFLD/NASH patients are also at higher risk of post-transplant cardiovascular events, diabetes, dyslipidemia, obesity, renal impairment and recurrent NASH. Lifestyle modifications, included diet and physical activity, are key to improve survival and quality of life after transplantation. A tailored immunosuppressive regimen may be proposed in selected patients. Development of new drugs for the treatment of recurrent NASH is awaited.
We analyze the behavior of the parsec-scale jet of the quasar 3C 454.3 during pronounced flaring in 2005-2008. Three major disturbances propagated down the jet along different trajectories with ...Lorentz factors {Gamma} > 10. The disturbances show a clear connection with millimeter-wave outbursts, in 2005 May/June, 2007 July, and 2007 December. High-amplitude optical events in the R-band light curve precede peaks of the millimeter-wave outbursts by 15-50 days. Each optical outburst is accompanied by an increase in X-ray activity. We associate the optical outbursts with propagation of the superluminal knots and derive the location of sites of energy dissipation in the form of radiation. The most prominent and long lasting of these, in 2005 May, occurred closer to the black hole, while the outbursts with a shorter duration in 2005 autumn and in 2007 might be connected with the passage of a disturbance through the millimeter-wave core of the jet. The optical outbursts, which coincide with the passage of superluminal radio knots through the core, are accompanied by systematic rotation of the position angle of optical linear polarization. Such rotation appears to be a common feature during the early stages of flares in blazars. We find correlations between optical variations and those at X-ray and {gamma}-ray energies. We conclude that the emergence of a superluminal knot from the core yields a series of optical and high-energy outbursts, and that the millimeter-wave core lies at the end of the jet's acceleration and collimation zone. We infer that the X-ray emission is produced via inverse Compton scattering by relativistic electrons of photons both from within the jet (synchrotron self-Compton) and external to the jet (external Compton, or EC); which one dominates depends on the physical parameters of the jet. A broken power-law model of the {gamma}-ray spectrum reflects a steepening of the synchrotron emission spectrum from near-IR to soft UV wavelengths. We propose that the {gamma}-ray emission is dominated by the EC mechanism, with the sheath of the jet supplying seed photons for {gamma}-ray events that occur near the millimeter-wave core.
Cardiac complications are a leading cause of mortality after orthotopic liver transplantation (LT) and pre-operative risk stratification is challenging. We evaluated whether coronary artery calcium ...(CAC) score calculated on a standard (non-thin layer, non-ECG gated) chest computed tomography (CT) predicted cardiac outcome after LT.
We included a consecutive series of LT recipients who underwent pre-operative cardiac evaluation including stress-testing or cardiac catheterization in high-risk patients. Patients with a history of coronary artery disease or coronary revascularization were excluded. The CAC score was calculated from the chest CT routinely performed before LT. CAC values were not available at the time of pre-transplant cardiac evaluation and did not affect LT eligibility. The primary end-point included peri-operative arrhythmic cardiac arrest and sustained ventricular arrhythmias; heart failure, myocardial infarction and cardiac death within 1-year after LT.
The study population consisted of 301 patients (median age 56 years, 76% males). At chest CT, 49% had CAC = 0; 27% had CAC = 1–99, 15% had CAC = 100–399 and 9% CAC > 400. The primary end-point incidence increased from 7% in patients with CAC = 0 to 27% in patients with CAC > 400 (p = 0.007). At multivariable analysis including traditional risk factors, CAC remained an independent predictor of cardiac events (p = 0.01).
CAC score calculated on a standard chest CT stratified the risk of cardiac events in patients who underwent LT after negative pre-transplant cardiac evaluation. These findings suggest that evaluation of CAC from a standard chest CT performed for other reasons can be used as an early cardiac risk stratification tool before LT.
•Cardiac complications are a leading cause of mortality after OLT•Pre-operative cardiological risk stratification is challenging and not standardized•Standard chest CT is routinely performed before OLT to exclude contraindications•CAC score on standard chest CT may be used as an early cardiac risk stratification tool
Liver transplantation (LT) has significantly transformed the prognosis of patients with end-stage liver disease and hepatocellular carcinoma (HCC). The traditional epidemiology of liver diseases has ...undergone a remarkable shift in indications for LT, marked by a decline in viral hepatitis and an increase in metabolic dysfunction-associated steatotic liver disease (MASLD), along with expanded indications for HCC. Recent advancements in surgical techniques, organ preservation and post-transplant patients' management have opened new possibilities for LT. Conditions that were historically considered absolute contraindications have emerged as potential new indications, demonstrating promising results in terms of patient survival. While these expanding indications provide newfound hope, the ethical dilemma of organ scarcity persists. Addressing this requires careful consideration and international collaboration to ensure equitable access to LT. Multidisciplinary approaches and ongoing research efforts are crucial to navigate the evolving landscape of LT. This review aims to offer a current overview of the primary emerging indications for LT, focusing on acute-on-chronic liver failure (ACLF), acute alcoholic hepatitis (AH), intrahepatic and perihilar cholangiocarcinoma (i- and p-CCA), colorectal liver metastasis (CRLM), and neuroendocrine tumor (NET) liver metastases.
SUMMARY
Patients with hepatocellular carcinoma (HCC) are at high risk of second primary malignancies. As HCC has become the leading indication of liver transplant (LT), the aim of this study was to ...investigate whether the presence of HCC before LT could influence the onset of de novo malignancies (DNM). A cohort study was conducted on 2653 LT recipients. Hazard ratios (HR) of DNM development for patients transplanted for HCC (HCC patients) were compared with those of patients without any previous malignancy (non‐HCC patients). All models were adjusted for sex, age, calendar year at transplant, and liver disease etiology. Throughout 17 903 person‐years, 6.6% of HCC patients and 7.4% of non‐HCC patients developed DNM (202 cases). The median time from LT to first DNM diagnosis was shorter for solid tumors in HCC patients (2.7 vs 4.5 years for HCC and non‐HCC patients, respectively, P < 0.01). HCC patients were at a higher risk of bladder cancer and skin melanoma. There were no differences in cumulative DNM‐specific mortality by HCC status. This study suggests that primary HCC could be a risk factor for DNM in LT recipients, allowing for risk stratification and screening individualization.
(1) Background: The purpose of this study is to investigate the effects of topical steroids on conjunctiva in patients undergoing filtration surgery (FS) for glaucoma by using confocal microscopy ...(CM); (2) Methods: One hundred and four glaucomatous patients were randomized to fluorometholone or lubricants four weeks before FS. CM was performed before treatments and pre-operatively. Dendritic and goblet cell densities (DCD, GCD), stromal meshwork reflectivity (SMR), vascular tortuosity (VT), and intra-ocular pressure (IOP) were the main outcomes. By evaluating treatments and outcomes (12-month success/failure) as categorical variables, patients were grouped into Group 1, 2, 3, or 4 (success/failure with fluorometholone, or lubricants); (3) Results: Twelve-month IOP was reduced in Groups 1 and 3 (p < 0.001). After treatments, DCD and SMR were reduced in Groups 1 and 2 (p < 0.01), and 1 and 3 (p < 0.05), respectively. Pre-operative DCD was lower in the steroid compared to lubricant group (p < 0.001), whereas SMR was lower in successful (1 and 3) compared to failed groups (2 and 4) (p = 0.004). There were no significant differences between the fluorometholone and lubricant groups for success percentages. The number of bleb management procedures and IOP lowering medications were lower in Group 1 compared to Groups 2−4 (p < 0.05); (4) Conclusions: Topical steroids mitigate conjunctival inflammation and lower the stromal density in patients undergoing FS. These modifications lead to less intensive post-operative management.
COVID-19 Acute Respiratory Distress Syndrome (CARDS) is the most serious complication of COVID-19. The SARS-CoV-2 outbreaks rapidly saturated intensive care unit (ICU), forcing the application of ...non-invasive respiratory support (NIRS) in respiratory intermediate care unit (RICU). The primary aim of this study is to compare the patients’ clinical characteristics and outcomes (Helmet-Continuous Positive Airway Pressure (H-CPAP) success/failure and survival/death). The secondary aim is to evaluate and detect the main predictors of H-CPAP success and survival/death. A total of 515 patients were enrolled in our observational prospective study based on CARDS developed in RICU during the three Italian pandemic waves. All selected patients were treated with H-CPAP. The worst ratio of arterial partial pressure of oxygen (PaO2) and fraction of inspired oxygen (FiO2) PaO2/FiO2 during H-CPAP stratified the subjects into mild, moderate and severe CARDS. H-CPAP success has increased during the three waves (62%, 69% and 77%, respectively) and the mortality rate has decreased (28%, 21% and 13%). H-CPAP success/failure and survival/death were related to the PaO2/FiO2 (worst score) ratio in H-CPAP and to steroids’ administration. D-dimer at admission, FiO2 and positive end expiratory pressure (PEEP) were also associated with H-CPAP success. Our study suggests good outcomes with H-CPAP in CARDS in RICU. A widespread use of steroids could play a role.
We explore the variability and cross-frequency correlation of the flux density and polarization of the blazar OJ287, using imaging at 43 GHz with the Very Long Baseline Array, as well as optical and ...near-infrared (near-IR) polarimetry. The polarization and flux density in both the optical waveband and the 43 GHz compact core increased by a small amount in late 2005, and increased significantly along with the near-IR polarization and flux density over the course of 10 days in early 2006. Furthermore, the values of the electric vector position angle (EVPA) at the three wavebands are similar. At 43 GHz, the EVPA of the blazar core is perpendicular to the flow of the jet, while the EVPAs of emerging superluminal knots are aligned parallel to the jet axis. The core polarization is that expected if shear aligns the magnetic field at the boundary between flows of disparate velocities within the jet. Using variations in flux density, percentage polarization, and EVPA, we model the inner jet as a spine-sheath system. The model jet contains a turbulent spine of half-width 12 and maximum Lorentz factor of 16.5, a turbulent sheath with Lorentz factor of 5, and a boundary region of sheared field between the spine and sheath. Transverse shocks propagating along the fast, turbulent spine can explain the superluminal knots. The observed flux density and polarization variations are then compatible with changes in the direction of the inner jet caused by a temporary change in the position of the core if the spine contains wiggles owing to an instability. In addition, we can explain a stable offset of optical and near-IR percentage polarization by a steepening of spectral index with frequency, as supported by the data.
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