Symmetric Vlasov-type antenna for High Power Microwave applications

We present a novel Vlasov-type antenna operating at 2.5 GHz and composed of a circular waveguide with a double bevel-cut. Simulation results show that the proposed antenna is capable of providing a wider emission angle if compared to standard Vlasov configurations, while still maintaining an adequate gain level. For this reason, it could be of interest for those High-Power Microwave (HPM) applications in which a larger area need to be covered by the EM field

Early carotid atherosclerosis and cardiac diastolic abnormalities in hypertensive subjects

Despite the fact that it is known that hypertension may be associated to early atherosclerosis manifestations, few data are to date available on the relationship between early carotid abnormalities and left ventricular diastolic dysfunction. To address this issue, 142 hypertensive patients (64 females and 78 males) younger than 55 years, at the first diagnosis of mild-to-moderate essential hypertension (WHO/ISH criteria), were selected from a database consisting of 3541 subjects referred to ultrasound cardiovascular laboratory in the last 5 years. Carotid intima-media thickness (IMT) was detected by high-resolution vascular ultrasound and left ventricular structure and function by the use of Doppler echocardiography. According to carotid IMT values, all patients were subgrouped into two groups consisting of 89 (62.6%) pts with IMT > or = 1 mm (A) and 53 (37.4%) pts with IMT < 1 mm (B). Our results show that isovolumic relaxation time (IVRT), deceleration time of E velocity (EDT) and left ventricular relative wall thickness (LV-RWT) were significantly (P < 0.05) higher in group A (IVRT 112 +/- 8.9 ms; EDT 288 +/- 21.8 ms; LV-RWT 0.40 +/- 0.08) than in group B (IVRT 92.3 +/- 4.6 ms; EDT 203.3 +/- 27.01 ms; LV- RWT 0.37 +/- 0.06). Moreover, the prevalence of left ventricular hypertrophy (LVH) was significantly (P < 0.01) higher in group A (30/89; 33.7%) than in group B (8/53; 15%). A positive correlation (P < 0.001) between IMT, EDT and IVRT was found only in hypertensives without LVH. These results are consistent with the indication that IMT evaluation has to be recommended both in hypertensive patients with LVH and in those without LVH, but with left ventricular diastolic dysfunction. This approach might improve the prognostic stratification of hypertensive subjects and it might be suitable to recognize the subset of patients at a higher risk of cardiovascular disease or events early

A Novel Conical Cut Frequency-Tapered Ring Bar SWS for High-Power and Wide-Bandwidth K-Band TWTs

This article presents a novel frequency-tapered Ring Bar Slow Wave Structure (RBSWS) for high-gain and wide-bandwidth Traveling Wave Tubes (TWTs) operating in the K-band for space applications. Starting from an analytical circuit model of the RBSWS, a conical-cut geometry is introduced to reduce the phase velocity. Our proposed novel RBSWS operates over a frequency range of 18.8 to 20.1 GHz, under a cathodic voltage and current of 19.8 kV and 0.3 A, respectively. Particle-In-Cell (PIC) results, carried out by CST Studio 2023, show a very high output peak power of 840.5 W at a gain of 20.2 dB, for an input power of 8 W, and an electron efficiency of 15.3%. The tapered RBSWS-TWT achieves a wider bandwidth, higher output power, and higher electron efficiency with respect to the untapered RBSWS-TWT, demonstrating the effectiveness of the proposed structure

Synergistic interactions of ionic liquids and antimicrobials improve drug efficacy.

Combinations of ionic liquids (ILs) with antimicrobial compounds have been shown to produce synergistic activities in model liposomes. In this study, imidazolium chloride-based ILs with alkyl tail length variations are combined with commercially available, small-molecule antimicrobials to examine the potential for combinatorial and synergistic antimicrobial effects on P. aeruginosa, E. coli, S. aureus, and S. cerevisiae. The effects of these treatments in a human cell culture model indicate the cytotoxic limits of ILs paired with antimicrobials. The analysis of these ILs demonstrates that the length of the alkyl chain on the IL molecule is proportional to both antimicrobial activity and cytotoxicity. Moreover, the ILs which exhibit synergy with small-molecule antibiotics appear to be acting in a membrane permeabilizing manner. Collectively, results from these experiments demonstrate an increase in antimicrobial efficacy with specific IL + antimicrobial combinations on microbial cultures while maintaining low cytotoxicity in a mammalian cell culture model

Use of bivalirudin for heparin-induced thrombocytopaenia after thrombolysis in massive pulmonary embolism: a case report

A 68-year-old man was referred to the emergency department 6 h after onset of sudden acute dyspnoea. Immediate ECG showed sinus tachycardia with the typical S1-Q3-T3 pattern and incomplete right bundle branch block. The echocardiogram showed the presence of mobile thrombus in the right atrium, a distended right ventricle with free wall hypokinesia and displacement of the interventricular septum towards the left ventricle. Lung spiral computed tomography (CT) showed bilateral pulmonary involvement and confirmed the picture of a thrombotic system in the right atrium and caval vein. Thrombolytic treatment with recombinant tissue plasminogen activator (rt-PA) and heparin (alteplase 10 mg bolus, then 90 mg over 2 h) was administered. Six hours after thrombolysis bleeding gums and significant reduction in platelet count (around 50,000) were observed. Heparin was discontinued and bivalirudin (0.1 mg/kg bolus and 1.75 mg/kg per h infusion) plus warfarin was initiated and continued for 5 days until the international normalised ratio (INR) was within the therapeutic range (2.0–3.0) for 2 consecutive days, with concomitant platelet count normalisation. Lung spiral and lower abdominal CT before discharge did not show the presence of clots in the pulmonary arteries of the right and left lung. This case suggests that bivalirudin could offer promise for use in patients with heparin-induced thrombocytopaenia (HIT) after thrombolysis for massive pulmonary embolism

Water and Sodium in Heart Failure: A Spotlight on Congestion.

Despite all available therapies, the rates of hospitalization and death from heart failure (HF) remain unacceptably high. The most common reasons for hospital admission are symptoms related to congestion. During hospitalization, most patients respond well to standard therapy and are discharged with significantly improved symptoms. Post-discharge, many patients receive diligent and frequent follow-up. However, rehospitalization rates remain high. One potential explanation is a persistent failure by clinicians to adequately manage congestion in the outpatient setting. The failure to successfully manage these patients post-discharge may represent an unmet need to improve the way congestion is both recognized and treated. A primary aim of future HF management may be to improve clinical surveillance to prevent and manage chronic fluid overload while simultaneously maximizing the use of evidence-based therapies with proven long-term benefit. Improvement in cardiac function is the ultimate goal and maintenance of a ‘‘dry’’ clinical profile is important to prevent hospital admission and improve prognosis. This paper focuses on methods for monitoring congestion, and strategies for water and sodium management in the context of the complex interplay between the cardiac and renal systems. A rationale for improving recognition and treatment of congestion is also proposed

Severity of Hepatocyte Damage and Prognosis in Cirrhotic Patients Correlate with Hepatocyte Magnesium Depletion

We aimed to evaluate the magnesium content in human cirrhotic liver and its correlation with serum AST levels, expression of hepatocellular injury, and MELDNa prognostic score. In liver biopsies obtained at liver transplantation, we measured the magnesium content in liver tissue in 27 cirrhotic patients (CIRs) and 16 deceased donors with healthy liver (CTRLs) by atomic absorption spectrometry and within hepatocytes of 15 CIRs using synchrotron-based X-ray fluorescence microscopy. In 31 CIRs and 10 CTRLs, we evaluated the immunohistochemical expression in hepatocytes of the transient receptor potential melastatin 7 (TRPM7), a magnesium influx chanzyme also involved in inflammation. CIRs showed a lower hepatic magnesium content (117.2 (IQR 110.5-132.9) vs. 162.8 (IQR 155.9-169.8) mu g/g; p &lt; 0.001) and a higher percentage of TRPM7 positive hepatocytes (53.0 (IQR 36.8-62.0) vs. 20.7 (10.7-32.8)%; p &lt; 0.001) than CTRLs. In CIRs, MELDNa and serum AST at transplant correlated: (a) inversely with the magnesium content both in liver tissue and hepatocytes; and (b) directly with the percentage of hepatocytes stained intensely for TRPM7. The latter also directly correlated with the worsening of MELDNa at transplant compared to waitlisting. Magnesium depletion and overexpression of its influx chanzyme TRPM7 in hepatocytes are associated with severity of hepatocyte injury and prognosis in cirrhosis. These data represent the pathophysiological basis for a possible beneficial effect of magnesium supplementation in cirrhotic patients

Thrombolysis for massive pulmonary embolism in pregnancy: a case report

Mortality from pulmonary embolism (PE) in pregnancy might be related to challenges in targeting the right population for prevention. Such targeting could help ensure that the correct diagnosis is suspected and adequately investigated, and allow the initiation of the timely and best possible treatment of this disease. In the literature to date only 18 case reports of thrombolysis in pregnant women with PE have been reported, and showed beneficial effects for both mother and fetus in terms of mortality and complications with acceptable bleeding risks. We present here the case of a pregnant patient with massive PE who underwent successful thrombolysis. A 26-year-old pregnant (at 24 weeks) woman was admitted 4 h after onset of sudden acute dyspnea and chest pain. An immediate electrocardiogram showed a typical S1-Q3-T3 pattern. The echocardiogram showed a distended right ventricle with free-wall hypokinesia and displacement of the interventricular septum toward the left ventricle. Thrombolysis with recombinant tissue plasminogen activator (alteplase 10 mg bolus, then 90 mg over 2 h) was administered. Pelvic examination and ultrasound showed regular fetal heart beat, and regular placental and liquid presence. No problems developed for the mother or fetus in the subsequent days or at discharge. In conclusion, in pregnant patients with life-threatening massive PE, thrombolytic therapy can be administered, and the use of echocardiographic, laboratory, and clinical data can be useful tools to achieve a rapid diagnosis and make a therapeutic decision, but additional studies need to be performed to further define its use