Carbon nanotubes tend to collapse when their diameters exceed a certain threshold, or sufficiently large external pressure is applied on walls. The radial stability of tubes has been studied in each these cases, however general theory able predict still lacking. Here, we propose simple model predicting limits as function the tube diameter, number walls and pressure. supported by atomistic simul...

The influence mechanism of the blade tip clearance (TC) an inducer on performance a centrifugal pump at high speed was researched under different flow rate conditions in this work. An experiment pump’s external carried out, and numerical calculation also performed four TCs. full characteristic curves, static pressure pulsation distributions were obtained. Through research analysis, it found tha...

BACKGROUND Blood pressure (BP) monitoring with arterial waveform display requires an arterial cannula. We evaluated a new noninvasive device, Vasotrac (Medwave, Arden Hills, MN) that provides BP measurements approximately every 12-15 beats and displays pulse rate and a calibrated arterial waveform for each BP measurement. METHODS Surgical and critically ill patients (n = 80) served as subject...

we report the case of a three-year-old girl who complained from dysphagia and post-prandial vomiting since she was 6months old. several diagnostic work-ups were performed for her problem. upper gi endoscopy was normal but barium swallow revealed an external pressure effect over upper part of the esophagus (figure 1) and the ct angiography of thoracic aorta showed that this external pressure eff...

conclusions complete recovery of the hand and finger extension was achieved in nine months. case presentation a 61 year-old man presented with the chief complaint of inability to extend the wrist and the fingers of the left hand which began suddenly the night before admission, following a three-week history of pain, numbness and tingling sensation of the affected extremity. he had no history of...

In their review on mechanical ventilation in severe asthma, Stather and Stewart [1] raise a concern that use of external positive end-expiratory pressure (PEEP) will result in increased total PEEP and worsened gas trapping [1]. Of critical importance to our understanding of whether application of external PEEP will be beneficial is assessment of the presence or absence of expiratory flow limita...

OBJECTIVE Manual assessment of radial arterial pulse character remains an important determinant of physiological status in military and civilian casualties. This study hypothesized that changes in radial pulse character and mental status (presyncopal symptoms) in humans occur only during the later stages of progressive reductions in central blood volume in close association with systolic blood ...

The digital volume pulse can be recorded simply and noninvasively by photoplethysmography. The objective of the present study was to determine whether a generalized transfer function can be used to relate the digital volume pulse to the peripheral pressure pulse and, hence, to determine whether both volume and pressure pulse waveforms are influenced by the same mechanism. The digital volume pul...

The prognostic value of central systolic blood pressure has been established recently. At present, its noninvasive assessment is limited by the need of dedicated equipment and trained operators. Moreover, ambulatory and home blood pressure monitoring of central pressures are not feasible. An algorithm enabling conventional automated oscillometric blood pressure monitors to assess central systol...

OBJECTIVE To determine the accuracy of peripheral (radial) arterial access as compared to central (femoral) arterial access for measurement of invasive blood pressure (IBP) in critically ill patients after cardiopulmonary bypass. METHODS Sixty patients (60) who required high inotropic/vasopressor support on weaning from cardio-pulmonary bypass and weaned off in 2nd attempt were included in th...