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Background: Noninvasive outpatient monitoring for heart failure (HF) has significant opportunity to reduce patient morbidity and the costs associated with recurrent hospitalization. The purpose of this study was to validate the ability of radiofrequency (RF) to assess lung fluid via a wearable patch device compared to thoracic CT in order to characterize volume overload. Methods: 120 subjects were studied: 66 acute heart failure (AHF) inpatients and 54 subjects without AHF (Control – 44 healthy and 10 stable HF). All underwent supine thoracic CT scans and supine RF readings from the wearable patch device placed on the left mid-axillary line (age = 74 ± 16 vs. 57 ± 15 yrs.; female = 38 vs. 44%; BMI = 33.2 ± 9.0 vs. 27.3 ± 5.1, AHF vs. Control respectively). Reflected RF signals and subject-specific anthropometric data were used to calculate the RF-determined lung fluid content. CT Lung fluid was reported as percentage of lung volume. Classification analyses were used to compare RF and CT performance. Results: AHF presented with higher lung fluid than controls by both CT and RF (CT: 20.1 ± 4.2% vs. 15.4 ± 2.4%; RF: 20.7 ± 5.6% vs. 15.6 ± 3.3%; p

Dense Si₃N₄-based composites with O'-SiAlON bonding phase were prepared by hot pressing of the mixture of Si₃N₄ matrix and polysiloxane (samples SA) and polysilazane (samples SB) based sintering aids. In both samples α-Si₃N₄ and β-Si₃N₄ were identified as major phases and O'-SiAlON with a chemical formula Si1.84Al0.16O1.16N1.84 as a minor phase. The hydrothermal corrosion tests were performed in subcritical conditions at 250 °C for 100 hours. The weight loss was rather low, 0.96 wt.% and 1.32 wt.% for samples SA and SB, respectively. The corrosion rate of samples SA and SB was 206 mg.m-2.h-1 and 233 mg.m-2.h-1. The higher corrosion rate of sample SB prepared with polysilazane-based sintering aid is most probably due to the hydrothermal dissolution of Si₃N₄ grains producing ammonia, as the pH value of eluate of this sample was higher, 8.5 compared to pH = 8.0 determined for sample SA. In sample SA a continuous SiO₂-based passivation layer was formed, while in sample SB the passivation layer was discontinuous and the corrosion medium could easily attack the Si₃N₄ grains. As the corrosion solution was more basic in sample SB, the SiO₂ passivation layer did not form so effectively, or dissolved faster than in sample SA. The higher corrosion resistance of sample SA was partly improved also by using Y₂O₃ sintering additive, which formed a rather stable Y₂SiO₅ phase.

One of main issues when evaluating or analysing quality and functional properties of work-piece is identification of status of residual stress. Every treatment or machining process generates residual stress in the surface and subsurface layers of the material structure. The residual stress has a large influence on the functional properties of the components. The article is focused on the method of triaxial measurement of residual stress after machining the surface of sample by high feed milling technology. Significance of triaxial measuring is the capability of measuring in different angles so it is possible to acquire stress tensor containing normal and shear stress components acting in the spot of measuring, using a Cartesian coordinate system.

This article deals with non-destructive detection method of residual stress as analytical tool of expected distribution of residual stress in surface and sub-surface layers. Based on measurements, which can consists of cloud of points, lines or surface map of residual stress, we can simulate potential distribution of residual stress in surface and subsurface layers via mathematical-statistical procedures. Right identification of residual stress and its distribution can improve the prediction of failures and similar damage incidences due to workload over lifetime of components and also, it can be used as evaluation parameter of suitability of applied manufacturing technological operations.

Sarcopenia, a syndrome commonly seen in elderly populations, is often characterized by a gradual loss of skeletal muscle, leading to the decline of muscle strength and physical performance. Growing evidence suggests that the prevalence of sarcopenia increases in patients with heart failure (HF), which is a dominant pathogenesis in the aging heart. HF causes diverse metabolic complications that may result in sarcopenia. Therefore, sarcopenia may act as a strong predictor of frailty, disability, and mortality associated with HF. Currently, standard treatments for slowing muscle loss in patients with HF are not available. Therefore, here, we review the pathophysiological mechanisms underlying sarcopenia in HF as well as current knowledge regarding the beneficial effects of exercise on sarcopenia in HF and related mechanisms, including hormonal changes, myostatin, oxidative stress, inflammation, apoptosis, autophagy, the ubiquitin-proteasome system, and insulin resistance.

Porous silicon nitride preforms designed for bone substitutes were prepared by two different forming methods: by introduction of semolina as pore forming agent and by template method with polyurethane sponge. Silicon nitride-based green bodies were sintered in air at two different temperatures, while the Si + 20 % Si3N4 samples were sintered by reaction bonding process in nitrogen. Template method yields samples with interconnected macroporous structure comparable to the bone structure while introduction of semolina results only in isolated macropores formation. All sintered samples were characterized in terms of phase composition and microstructure. Moreover, some of the mechanical properties (hardness, elastic modulus, bending strength) were measured and compared to the bone properties in order to select the most suitable method for the preparation of trabecular bone substitute. Despite of relatively low strength, the template method with subsequent sintering in air appeared to be the most promising way for the preparation of trabecular bone-like silicon nitride-based porous ceramic structures, whereas the hardness and elastic modulus of as prepared samples were in perfect accordance with bone characteristics.

Cardiovascular diseases are one of most frequent cause of morbidity and mortality in the world. There is an emerging need for integrated, non-invasive, and easy-to-use clinical tools to assess accurately cardiovascular system primarily in the preventative medicine. We present a novel design for a non-invasive pulse wave velocity (PWV) assessment method integrated in a single brachial blood pressure monitor allowing for up to 100 times more sensitive recording of the pressure pulsations based on a brachial occlusion-cuff (suprasystolic) principle. The monitor prototype with built-in proprietary method was validated with a gold standard reference technique SphygmoCor VX device. The blood pressure and PWV were assessed on twenty-five healthy individuals (9 women, age (37 ± 13) years) in a supine position at rest by a brachial cuff blood pressure monitor prototype, and immediately re-tested using a gold standard method. PWV using our BP monitor was (6.67 ± 0.96) m/s compared to PWV determined by SphygmoCor VX (6.15 ± 1.01) m/s. The correlation between methods using a Pearson’s correlation coefficient was r = 0.88 (p < 0.001). The study demonstrates the feasibility of using a single brachial cuff build-in technique for the assessment of the arterial stiffness from a single ambulatory blood pressure assessment.

The thermal spalling action of material removal associated with electrical discharge machining of ceramics results in severe surface debris, cracks, pores, etc. This led to a rough machined surface, ultimately rendering the machined component not susceptible for direct applications. Such a behavior points towards the need to further process the machined surface so as to reduce the net severity of the machined surface. The current work utilizes multi-pass wire electrical discharge machining to enhance the machined surface characteristics of alumina composites. Detailed comparison of the surface characteristics with regards to amplitude, spatial, hybrid and functional volume parameters depicted a superior and homogenous machined surface post multi-pass process. The recast layer severity was minimal as well by incorporation of multi-pass. Furthermore, a detailed analysis of the structural fingerprints of the surface elements depicts actual breakage and subsequent burn-out of the filler material. • Successful reduction of the surface severities post multi pass WEDM process, leading to a very fine machined surface. • Detailed surface characterization depicts reduction of peaks/valleys, paving way for high homogeneity of the machined surface. • Spatial and hybrid surface analysis depicts consistent removal of the peaks and subsequent filling of the valleys/voids with multi pass. • The porous network and the recast layer severity decreases considerably post multi pass due to subsequent filling and removal action. [ABSTRACT FROM AUTHOR]

BACKGROUND: Methacholine bronchoprovocation or challenge testing (MCT) is commonly performed to assess airway hyper-responsiveness in the setting of suspected asthma. Nebulization is an aerosol-generating procedure, but little is known about the risks of MCT in the context of the ongoing coronavirus disease 2019 (COVID-19) pandemic. We aimed to quantify and characterize aerosol generation during MCT by using different delivery methods and to assess the impact of adding a viral filter. METHODS: Seven healthy subjects performed simulated MCT in a near particle-free laboratory space with 4 different nebulizers and with a dosimeter. Two devices continuously sampled the ambient air during the procedure, which detected ultrafine particles, from 0.02--1 μm, and particles of sizes 0.3, 0.5, 1.0, 2.0, 5.0, and 10 µm, respectively. Particle generation was compared among all the devices, with and without viral filter placement. RESULTS: Ultrafine-particle generation during simulated MCT was significant across all the devices. Ultrafine-particle (0.02--1 μm) concentrations decreased 77%--91% with the addition of a viral filter and varied significantly between unfiltered (P < .001) and filtered devices (P < .001). Ultrafine-particle generation was lowest when using the dosimeter with filtered Hudson nebulizer (1,258 ± 1,644 particle/mL). Ultrafine-particle concentrations with the filtered nebulizer devices using a compressor were higher than particle concentrations detected when using the dosimeter: Monaghan (3,472 ± 1,794 particles/mL), PARI (4,403 ± 2,948), Hudson (6,320 ± 1,787) and AirLife (9,523 ± 5,098). CONCLUSIONS: The high particle concentrations generated during MCT pose significant infection control concerns during the COVID-19 pandemic. Particle generation during MCT was significantly reduced by using breath-actuated delivery and a viral filter, which offers an effective mitigation strategy. [ABSTRACT FROM AUTHOR]

BACKGROUND: Peak flow testing is a common procedure performed in ambulatory care. There are currently no data regarding aerosol generation during this procedure. Given the ongoing debate regarding the potential for aerosol transmission of SARS-CoV-2, we aimed to quantify and characterize aerosol generation during peak flow testing. METHODS: Five healthy volunteers performed peak flow maneuvers in a particle-free laboratory space. Two devices continuously sampled the ambient air during the procedure. One device can detect ultrafine particles 0.02-1 µm in diameter, while the second device can detect particles 0.3, 0.5, 1.0, 2.0, 5.0, and 10 lm in diameter. Five different peak flow meters were compared to ambient baseline during masked and unmasked tidal breathing. RESULTS: Ultrafine particles (0.02-1 µm) were generated during peak flow measurement. There was no significant difference in ultrafine particle mean concentration between peak flow meters (P = .23): Respironics (1.25 ± 0.47 particles/mL), Philips (3.06 ± 1.22), Clement Clarke (3.55 ± 1.22 particles/mL), Respironics Low Range (3.50 ± 1.52 particles/mL), and Monaghan (3.78 ± 1.31 particles/mL). Ultrafine particle mean concentration with peak flow testing was significantly higher than masked (0.22 ± 0.29 particles/mL) and unmasked tidal breathing (0.15 ± 0.18 particles/mL, P = .01), but the ultrafine particle concentrations were small compared to ambient particle concentrations in a pulmonary function testing room (89.9 ± 8.95 particles/mL). CONCLUSIONS: In this study, aerosol generation was present during peak flow testing, but concentrations were small compared to the background particle concentration in the ambient clinical environment. Surgical masks and eye protection are likely sufficient infection control measures during peak expiratory flow testing in asymptomatic patients with well controlled respiratory symptoms, but COVID-19 testing remains prudent in patients with acute respiratory symptoms prior to evaluation and peak expiratory flow assessment while the community prevalence of SARS-CoV-2 cases remains high. [ABSTRACT FROM AUTHOR]

Abstract Background Peripheral nerve blocks are effective in treating acute pain, thereby minimizing the requirement for opiate analgesics. Fractured neck of femur (FNF) is a common, painful injury. The provision of effective analgesia to this cohort is challenging but an important determinant of their functional outcome. We investigated the analgesic efficacy of continuous femoral nerve block (CFNB) in patients with FNF. Methods Following institutional ethical approval and with informed consent, patients awaiting FNF surgery were randomly allocated to receive either standard opiate-based analgesia (Group 1) or a femoral perineural catheter (Group 2). Patients in Group 1 received parenteral morphine as required. Those in Group 2 received a CFNB comprising a bolus of local anaesthetic followed by a continuous infusion of 0.25% bupivacaine. For both Groups, rescue analgesia consisted of intramuscular morphine as required and all patients received paracetamol regularly. Pain was assessed using a visual analogue scale at rest and during passive movement (dynamic pain score) at 30 min following first analgesic intervention and six hourly thereafter for 72 hours. Patient satisfaction with the analgesic regimen received was recorded using verbal rating scores (0-10). The primary outcome measured was dynamic pain score from initial analgesic intervention to 72 hours later. Results Of 27 recruited, 24 patients successfully completed the study protocol and underwent per protocol analysis. The intervals from recruitment to the study until surgery were similar in both groups [31.4(17.7) vs 27.5(14.2) h, P = 0.57]. The groups were similar in terms of baseline clinical characteristics. For patients in Group 2, pain scores at rest were less than those reported by patients in Group 1 [9.5(9.4) vs 31(28), P = 0.031]. Dynamic pain scores reported by patients in Group 2 were less at each time point from 30 min up to 54 hours [e.g at 6 h 30.7(23.4) vs 67.0(32.0), P = 0.004]. Cumulative morphine consumption over 72 h was less in Group 2. Patient satisfaction scores were greater in Group 2 [9.4(1.1) vs 7.6(1.8), P = 0.014]. Conclusions CFNB provides more effective perioperative analgesia than a standard opiate-based regimen for patients undergoing fixation of FNF. It is associated with lesser opiate use and greater patient satisfaction.

The high cost of silicon carbide and its associated difficulties in machining due to high hardness have long been a major hindrance towards successful applications in various industries, ranging from marine to aerospace sectors. This imparts a need to identify a suitable machining process that can machine silicon carbides with ease and at the same time generate complicated profiles. Therefore, the present work is an effort to identify the possibility of machining silicon carbides with wire electrical discharge machining process. In the current work, the silicon carbides being fabricated by rapid hot-pressing technique led to in-situ graphene formation. This graphene particles, in turn, aid the electrical discharge machining process by imparting a higher electron transfer rate through the workpiece. The influence of open voltage and servo voltage on the overall machinability were thoroughly investigated with machining rate, kerf width and surface roughness as the output characteristics. The variation in the intensity of discharge energy with open voltages had a direct influence on the formation of discharge crater which in turn, affected the overall output characteristics. This led to a gradual increase in the machining rate and the associated surface roughness with an increase in the open voltage. On the other hand, the increase in the servo voltage from 25 V to 39 V led to an initial increase in the machining rate which again decreases when the servo voltage further increases to 51 V. This variation in the machining rate was mainly due to the varying concentration of discharge, open and arcing pulses with varying servo voltage, with arcing pulses more dominant in lower servo voltage and open pulses in larger servo voltage. A minimum kerf width in the range of 170 µm was obtained in the present study with a wire tool of diameter 150 µm when the servo voltage was maintained at 25 V. Further, the kerf width was observed to increase with an increase in the servo voltage throughout the considered range. This is mainly due to the higher discharge concentration in the transverse direction as compared to the machining direction with an increase in the servo voltages. Moreover, a rougher machined surface with high debris concentration was observed when machined with lower servo voltages for all the considered open voltages. This behavior is mainly attributed by the high arcing phenomenon and ineffective removal of the eroded debris across the small inter-electrode gap by the dielectric fluid. [ABSTRACT FROM AUTHOR]

Previous studies on the safety of peri-operative transoesophageal echocardiography seem to suggest a low rate of associated morbidity and mortality. That said, there has been a paucity of prospective multicentre studies in this important area of clinical practice. We carried out a one-year prospective study in 2017, co-ordinated by the Association of Cardiothoracic Anaesthesia and Critical Care, to determine the rate and severity of complications associated with peri-operative transoesophageal echocardiography in anaesthetised cardiology and cardiac surgical patients. With the help of clinicians from 28 centres across the UK and Ireland, we recorded the total number of examinations conducted in anaesthetised patients during the study period. All major complications at each centre were prospectively reported and recorded. Of the 22,314 examinations, there were 17 patients diagnosed with a major complication which caused either palatal injury or gastro-oesophageal disruption. This corresponds to an incidence of 0.08% (95%CI 0.05-0.13%) or approximately 1:1300 examinations. There were seven deaths reported during the study period which were directly attributed to these complications, corresponding to an incidence of 0.03% (95%CI 0.01-0.07%) or approximately 1:3000. These figures are higher than previously reported and suggest a high probability of death following the development of a complication (~40%). Most complications occurred in patients without known risk factors for transoesophageal echocardiography associated gastro-oesophageal injury. We suggest clinicians and departments review their procedural guidelines, especially in relation to probe insertion techniques, together with the information communicated to patients when the risks and benefits of such examinations are discussed. [ABSTRACT FROM AUTHOR]