Helicopter rotor trailing edge noise

A two dimensional section of a helicopter main rotor blade was tested in an acoustic wind tunnel at close to full-scale Reynolds numbers to obtain boundary layer data and acoustic data for use in developing an acoustic scaling law and testing a first principles trailing edge noise theory. Results were extended to the rotating frame coordinate system to develop a helicopter rotor trailing edge noise prediction. Comparisons of the calculated noise levels with helicopter flyover spectra demonstrate that trailing edge noise contributes significantly to the total helicopter noise spectrum at high frequencies. This noise mechanism is expected to control the minimum rotor noise. In the case of noise radiation from a local blade segment, the acoustic directivity pattern is predicted by the first principles trailing edge noise theory. Acoustic spectra are predicted by a scaling law which includes Mach number, boundary layer thickness and observer position. Spectrum shape and sound pressure level are also predicted by the first principles theory but the analysis does not predict the Strouhal value identifying the spectrum peak

Pregnancy in Women with Congenital Heart Disease: A Guide for the General Cardiologist

Remarkable advances in the care and survival of congenital heart disease (CHD) patients have led to increasing numbers of young women with CHD who carry a pregnancy with significant risk. The profound hemodynamic changes that naturally occur during gestation may unmask CHD or exacerbate an existing condition and place both the woman and fetus in jeopardy. The caring cardiologist should be familiar with the specific lesion and anticipate complications. Pregestational counseling and a multidisciplinary team approach during pregnancy are key for a successful pregnancy and favorable outcomes. In this review we discuss the evaluation of the expecting CHD patient and focus on the commonly encountered lesions

SOSIALISASI KOMISI YUDISIAL MALUKU UNTUK MEMBANGUN PERADILAN BERSIH DI NEGERI LATUHALAT

Sosialisasi peradilan bersih dilaksanakan di desa Latuhalat guna untuk meningkatkan pemahaman dan peran masyarakat Negeri Latuhalat dengan tujuan untuk menciptakan peran masyarakat dalam mewujudkan peradilan yang bersih yang bebas dari praktek kolusi, korupsi,dan nepotisme agar terwujudnya keadilan dalam masyarakat, pemahaman masarakat terkait peradilan bersih dan lembaga terkait yang berperan penting dalam menciptakan peradilan bersih seperti Komisi Yudisial sangatlah penting. Komisi yudisial merupakan lembaga tinggi negara yang independen yang bergerak di bidang pengawasan hakim, kegiatan ini dilaksanakan pada tangal 3 november sampai 4 november 2021 kantor desa Latuahalat. Sasaran yang ditujukan adalah masyarakat Negeri Latuhalat metode yang digunakan adalah memberikan edukasi langsung dengan cara membagai brosur berisikan alur alur pelaporan hakim yang melanggar kode etik. Dalam kegiatan ini ada dua tahapan yang dilalui yang pertama komisi yudisial mensosialisasikan kepada mahasiswa KKN Negeri Latuhalat, yang kedua mahasiswa membagikan brosur dan buku mini ke masyarakat sekaligus menerangkan terkait isi dari brosur dan buku tersebut. Dengan adanya sosialisasi peradilan bersih ini maka masyarakat akan lebih memahami peran - perannya dalam mewujudkan peradilan yang bersih. Peradilan bersih merupakan hal yang sangat penting dalam mewujudkan keadilan dalam masyarakat, salah satu peran masyarakat dalam mewujudkan peradilan bersih adalah memahami alur - alur pelaporan hakim yang melanggar kode etik dan pedoman perilaku hakim sesuai peraturan perundang undangan yang berlaku

Metabolic profiling of Ochradenus baccatus Delile. utilizing UHPLC-HRESIMS in relation to the in vitro biological investigations

Ochradenus baccatus Delile (Resedaceae) is a desert plant with edible fruits native to the Middle East. Few investigators have reported antibacterial, antiparasitic and anti-cancer activities of the plant. Herein we evaluated the cytotoxic activity of O. baccatus using four cell lines and a zebrafish embryo model. Additionally, liquid chromatography coupled with mass spectroscopy was performed to characterize the extract’s main constituents. The highest cytotoxicity was observed against human cervical adenocarcinoma (HeLa), with CC50 of 39.1 μg/mL and a selectivity index (SI) of 7.23 (p < 0.01). Metabolic analysis of the extract resulted in the annotation of 57 metabolites, including fatty acids, flavonoids, glucosinolates, nitrile glycosides, in addition to organic acids. The extract showed an abundance of hydroxylated fatty acids (16 peaks). Further, 3 nitrile glycosides have been identified for the first time in Ochradenus sp., in addition to 2 glucosinolates. These identified phytochemicals may partially explain the cytotoxic activity of the extract. We propose O. baccatus as a possible safe food source for further utilization to partially contribute to the increasing food demand specially in Saharan countries.Medical University of Lublin | Ref. DS28Universidade de Vigo/CISU

Design of the ExCersion-VCI study: The effect of aerobic exercise on cerebral perfusion in patients with vascular cognitive impairment

There is evidence for a beneficial effect of aerobic exercise on cognition, but underlying mechanisms are unclear. In this study, we test the hypothesis that aerobic exercise increases cerebral blood flow (CBF) in patients with vascular cognitive impairment (VCI). This study is a multicenter single-blind randomized controlled trial among 80 patients with VCI. Most important inclusion criteria are a diagnosis of VCI with Mini-Mental State Examination ≥22 and Clinical Dementia Rating ≤0.5. Participants are randomized into an aerobic exercise group or a control group. The aerobic exercise program aims to improve cardiorespiratory fitness and takes 14 weeks, with a frequency of three times a week. Participants are provided with a bicycle ergometer at home. The control group receives two information meetings. Primary outcome measure is change in CBF. We expect this study to provide insight into the potential mechanism by which aerobic exercise improves hemodynamic status

Design of the ExCersion-VCI study: The effect of aerobic exercise on cerebral perfusion in patients with vascular cognitive impairment

There is evidence for a beneficial effect of aerobic exercise on cognition, but underlying mechanisms are unclear. In this study, we test the hypothesis that aerobic exercise increases cerebral blood flow (CBF) in patients with vascular cognitive impairment (VCI). This study is a multicenter single-blind randomized controlled trial among 80 patients with VCI. Most important inclusion criteria are a diagnosis of VCI with Mini-Mental State Examination ≥22 and Clinical Dementia Rating ≤0.5. Participants are randomized into an aerobic exercise group or a control group. The aerobic exercise program aims to improve cardiorespiratory fitness and takes 14 weeks, with a frequency of three times a week. Participants are provided with a bicycle ergometer at home. The control group receives two information meetings. Primary outcome measure is change in CBF. We expect this study to provide insight into the potential mechanism by which aerobic exercise improves hemodynamic status

Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

The pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age=61 +/- 8 years) and 5 age/gender matched controls (age=56 +/- 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities<10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.12.4 cm/s vs. 16.7 +/- 2.1 cm/s, p=0.01) and (19.3 +/- 4.7 cm/s vs. 26.8 +/- 5.5 cm/s, p=0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 +/- 10.8% vs. 27.8 +/- 7.9%, p=0.01) and in the LA appendage (73.3 +/- 5.7% vs. 52.8 +/- 16.2%, p=0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.Cardiovascular Aspects of Radiolog

Non-invasive assessment of damping of blood flow velocity pulsatility in cerebral arteries with MRI

Background Damping of heartbeat-induced pressure pulsations occurs in large arteries such as the aorta and extends to the small arteries and microcirculation. Since recently, 7 T MRI enables investigation of damping in the small cerebral arteries. Purpose To investigate flow pulsatility damping between the first segment of the middle cerebral artery (M1) and the small perforating arteries using magnetic resonance imaging. Study Type Retrospective. Subjects Thirty-eight participants (45% female) aged above 50 without history of heart failure, carotid occlusive disease, or cognitive impairment. Field Strength/Sequence 3 T gradient echo (GE) T1-weighted images, spin-echo fluid-attenuated inversion recovery images, GE two-dimensional (2D) phase-contrast, and GE cine steady-state free precession images were acquired. At 7 T, T1-weighted images, GE quantitative-flow, and GE 2D phase-contrast images were acquired. Assessment Velocity pulsatilities of the M1 and perforating arteries in the basal ganglia (BG) and semi-oval center (CSO) were measured. We used the damping index between the M1 and perforating arteries as a damping indicator (velocity pulsatility(M1)/velocity pulsatility(CSO/BG)). Left ventricular stroke volume (LVSV), mean arterial pressure (MAP), pulse pressure (PP), and aortic pulse wave velocity (PWV) were correlated with velocity pulsatility in the M1 and in perforating arteries, and with the damping index of the CSO and BG. Statistical Tests Correlations of LVSV, MAP, PP, and PWV with velocity pulsatility in the M1 and small perforating arteries, and correlations with the damping indices were evaluated with linear regression analyses. Results PP and PWV were significantly positively correlated to M1 velocity pulsatility. PWV was significantly negatively correlated to CSO velocity pulsatility, and PP was unrelated to CSO velocity pulsatility (P = 0.28). PP and PWV were uncorrelated to BG velocity pulsatility (P = 0.25; P = 0.68). PWV and PP were significantly positively correlated with the CSO damping index. Data Conclusion Our study demonstrated a dynamic damping of velocity pulsatility between the M1 and small cerebral perforating arteries in relation to proximal stress. Level of Evidence 4 Technical Efficacy Stage 1Cardiovascular Aspects of Radiolog

Experimental study of the wear behaviour of a metal carbide tool in turning by dimensionless analysis

Purpose: In this article, we present the experimental results with a dimensionless analysis of the wear behavior of a metal carbide tool in a turning operation. Design/methodology/approach: The highlighting of the dimensional input and output parameters of the experimental tests to bring out the different adimensional parameters. Regarding the input parameters, we have the rotational velocity (N), the feed (f), the depth of cut (ap), the machining time (t). The output parameters are defined by the flow rate (DC), the volume of the used tip (VU), the face wear (VB), as well as the cutting power (PC) and that of the machine (PM). Findings: The dimensionless approach allowed us to find the desired cutting conditions as well as the possibility of working in ranges of cutting conditions for known wear, which is not possible with a dimensional analysis. It should be noted that the appropriate choice of these parameters was essential to achieve these results. Research limitations/implications: The existence of a working range proposed by this analysis leads us to the proposal of a model and a numerical optimization. Practical implications: This work offers the desired compromise of adequate cutting conditions during machining. Originality/value: Deduction of adequate cutting conditions with minimum wear. Among other things, we can extrapolate the results to offer us compromises in the choice of ranges of cutting conditions