Effects of air dissolution dynamics on the behaviour of positive-displacement vane pumps: a simulation approach

The aim of this paper is to evaluate the effects of the dissolution time – time for the liquid to absorb the gas till the saturation state - on the behaviour of positivedisplacement vane pumps, in terms of pressure peaks within internal chambers and forces applied to the stator ring. The chamber pressurization depends on the volume variation and fluid Bulk modulus in the pre-compression phase during which the volume is trapped between the suction and the delivery port rims. If the dissolution time is short, then the entrained air is quickly absorbed and the fluid Bulk modulus sharply increases just before opening the connection to the outlet; as a consequence, pressure peaks may appear thus degrading the NVH characteristics of the pump. Moreover the pressure within internal chambers generate i) a torque demand to the driver (the combustion engine or an electrical motor) and ii) a total force applied to the stator ring. In case of fixed displacement designs, the resultant pressure force simply represents a load for support bearings; while in case of variable designs, it contributes to the displacement regulation. Simulation results show that the pump behaviour is very sensitive to the dissolution time when it is quite close to the duration of the trapped period

Immunogenicity and Safety of Anti-SARS-CoV-2 mRNA Vaccines in a Cohort of Patients with Hereditary Angioedema

Many factors may trigger hereditary angioedema (HAE) attacks. This study aims to gain insights into the benefits and potential risks of COVID-19 vaccination in HAE patients, focusing particularly on the possibility of triggering attacks. We enrolled 31 patients with HAE undergoing two doses of the SARS-CoV-2 mRNA Comirnaty-BioNTech/Pfizer vaccine. To evaluate the possible influence of the vaccine on disease control and attack frequency, we administered the angioedema control test (AECT) 4-week version before (T0), 21 days after the first dose (T1), and between 21 and 28 days after the second dose (T2). Despite 5 patients (16.1%) experiencing attacks within 72 h of the first dose administration, no significant variation in attack frequency was observed before and after vaccination [F(2,60) = 0.123; p = 0.799]. In addition, patients reported higher AECT scores at T1 and T2 compared to T0 [F(2,44) = 6.541; p < 0.05; post hoc p < 0.05)], indicating that the disease was rather more controlled after vaccinations than in the previous period. All patients showed a positive serological response to the vaccine without significant differences from healthy controls (U = 162; p = 0.062). These observations suggest that the vaccine administration is safe and effective in HAE patients

Dupilumab in the treatment of severe uncontrolled chronic rhinosinusitis with nasal polyps (CRSwNP): A multicentric observational Phase IV real-life study (DUPIREAL)

Background Chronic rhinosinusitis with nasal polyps (CRSwNP) is associated with significant morbidity and reduced health-related quality of life. Findings from clinical trials have demonstrated the effectiveness of dupilumab in CRSwNP, although real-world evidence is still limited. Methods This Phase IV real-life, observational, multicenter study assessed the effectiveness and safety of dupilumab in patients with severe uncontrolled CRSwNP (n = 648) over the first year of treatment. We collected data at baseline and after 1, 3, 6, 9, and 12 months of follow-up. We focused on nasal polyps score (NPS), symptoms, and olfactory function. We stratified outcomes by comorbidities, previous surgery, and adherence to intranasal corticosteroids, and examined the success rates based on current guidelines, as well as potential predictors of response at each timepoint. Results We observed a significant decrease in NPS from a median value of 6 (IQR 5–6) at baseline to 1.0 (IQR 0.0–2.0) at 12 months (p &lt; .001), and a significant decrease in Sino-Nasal Outcomes Test-22 (SNOT-22) from a median score of 58 (IQR 49–70) at baseline to 11 (IQR 6–21; p &lt; .001) at 12 months. Sniffin' Sticks scores showed a significant increase over 12 months (p &lt; .001) compared to baseline. The results were unaffected by concomitant diseases, number of previous surgeries, and adherence to topical steroids, except for minor differences in rapidity of action. An excellent-moderate response was observed in 96.9% of patients at 12 months based on EPOS 2020 criteria. Conclusions Our findings from this large-scale real-life study support the effectiveness of dupilumab as an add-on therapy in patients with severe uncontrolled CRSwNP in reducing polyp size and improving the quality of life, severity of symptoms, nasal congestion, and smell

Phase 3, Randomized, 20-Month Study of the Efficacy and Safety of Bimatoprost Implant in Patients with Open-Angle Glaucoma and Ocular Hypertension (ARTEMIS 2)

Objective- To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of 10 and 15 µg bimatoprost implant in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). Methods- This randomized, 20-month, multicenter, masked, parallel-group, phase 3 trial enrolled 528 patients with OAG or OHT and an open iridocorneal angle inferiorly in the study eye. Study eyes were administered 10 or 15 µg bimatoprost implant on day 1, week 16, and week 32, or twice-daily topical timolol maleate 0.5%. Primary endpoints were IOP and IOP change from baseline through week 12. Safety measures included treatment-emergent adverse events (TEAEs) and corneal endothelial cell density (CECD). Results- Both 10 and 15 µg bimatoprost implant met the primary endpoint of noninferiority to timolol in IOP lowering through 12 weeks. Mean IOP reductions from baseline ranged from 6.2–7.4, 6.5–7.8, and 6.1–6.7 mmHg through week 12 in the 10 µg implant, 15 µg implant, and timolol groups, respectively. IOP lowering was similar after the second and third implant administrations. Probabilities of requiring no IOP-lowering treatment for 1 year after the third administration were 77.5% (10 µg implant) and 79.0% (15 µg implant). The most common TEAE was conjunctival hyperemia, typically temporally associated with the administration procedure. Corneal TEAEs of interest (primarily corneal endothelial cell loss, corneal edema, and corneal touch) were more frequent with the 15 than the 10 µg implant and generally were reported after repeated administrations. Loss in mean CECD from baseline to month 20 was ~ 5% in 10 µg implant-treated eyes and ~ 1% in topical timolol-treated eyes. Visual field progression (change in the mean deviation from baseline) was reduced in the 10 µg implant group compared with the timolol group. Conclusions- The results corroborated the previous phase 3 study of the bimatoprost implant. The bimatoprost implant met the primary endpoint and effectively lowered IOP. The majority of patients required no additional treatment for 12 months after the third administration. The benefit-risk assessment favored the 10 over the 15 µg implant. Studies evaluating other administration regimens with reduced risk of corneal events are ongoing. The bimatoprost implant has the potential to improve adherence and reduce treatment burden in glaucoma

Effects of air dissolution dynamics on the behaviour of positive-displacement vane pumps: a simulation approach

The aim of this paper is to evaluate the effects of the dissolution time – time for the liquid to absorb the gas till the saturation state - on the behaviour of positivedisplacement vane pumps, in terms of pressure peaks within internal chambers and forces applied to the stator ring. The chamber pressurization depends on the volume variation and fluid Bulk modulus in the pre-compression phase during which the volume is trapped between the suction and the delivery port rims. If the dissolution time is short, then the entrained air is quickly absorbed and the fluid Bulk modulus sharply increases just before opening the connection to the outlet; as a consequence, pressure peaks may appear thus degrading the NVH characteristics of the pump. Moreover the pressure within internal chambers generate i) a torque demand to the driver (the combustion engine or an electrical motor) and ii) a total force applied to the stator ring. In case of fixed displacement designs, the resultant pressure force simply represents a load for support bearings; while in case of variable designs, it contributes to the displacement regulation. Simulation results show that the pump behaviour is very sensitive to the dissolution time when it is quite close to the duration of the trapped period

Effects of air dissolution dynamics on the behaviour of positive-displacement vane pumps: a simulation approach

The aim of this paper is to evaluate the effects of the dissolution time – time for the liquid to absorb the gas till the saturation state - on the behaviour of positivedisplacement vane pumps, in terms of pressure peaks within internal chambers and forces applied to the stator ring. The chamber pressurization depends on the volume variation and fluid Bulk modulus in the pre-compression phase during which the volume is trapped between the suction and the delivery port rims. If the dissolution time is short, then the entrained air is quickly absorbed and the fluid Bulk modulus sharply increases just before opening the connection to the outlet; as a consequence, pressure peaks may appear thus degrading the NVH characteristics of the pump. Moreover the pressure within internal chambers generate i) a torque demand to the driver (the combustion engine or an electrical motor) and ii) a total force applied to the stator ring. In case of fixed displacement designs, the resultant pressure force simply represents a load for support bearings; while in case of variable designs, it contributes to the displacement regulation. Simulation results show that the pump behaviour is very sensitive to the dissolution time when it is quite close to the duration of the trapped period

Modelling of a Variable Displacement Lubricating Pump with Air Dissolution Dynamics

The simulation of lubricating pumps for internal combustion engines has always represented a challenge due to the high aeration level of the working fluid. In fact, the delivery pressure ripple is highly influenced by the effective fluid bulk modulus, which is significantly reduced by the presence of separated air. This paper presents a detailed lumped parameter model of a variable displacement vane pump with a two-level pressure setting, in which the fluid model takes into account the dynamics of release and dissolution of the air in the oil. The pump was modelled in the LMS Imagine.Lab Amesim® environment through customized libraries for the evaluation of the main geometric features. The model was validated experimentally in terms of pressure oscillations in conditions of low and high aeration. The fraction of separated air in the reservoir of the test rig was measured by means of an X-ray technique. The pump was tested in two different configurations of the displacement control: direct acting for the low-pressure level, pilot operated for the high setting. It was found that the former configuration is more sensitive to the presence of separated air, since the variation of the pressure peaks in the variable volume chambers alters the equilibrium of the stator ring. Overall, the model has been proved to be reliable not only for the evaluation of the mean pressure level imposed by the displacement control, but also in the assessment of the pressure amplitude and in most cases even in the reproduction of the pressure waveform