P1806 Relation between carotid artery wave intensity compression wave and left ventricular dp/dt

Background Invasive catheter-based studies demonstrated a correlation between left ventricular (LV) dP/dt, a well known index of contractility, and carotid artery wave intensity compression wave. It is possible to estimate LV dP/dt with ultrasound, evaluating the slope of continuous Doppler wave of mitral regurgitation in early systole. Wave intensity (WI) is achieved merging the echo-tracking of the common carotid artery with the simultaneous pulsed Doppler signal inside the vessel. The first peak (W1) represents the forward compression wave, reflecting theoretically LV contractile function. Nowadays data about the relationship between the two dP/dt methods are scarce. Purpose The aim of the study is to compare carotid artery WI and mitral regurgitation wave-derived LV dP/dt in a population of patients with ischemic and not ischemic heart failure. Methods We examined 31 consecutive patients with heart failure (7 females, 24 males, mean age 66.7 + 13.9 years, range 29-97 years, 21 ischemic, 10 not ischemic). All patients had at least a mild mitral regurgitation. Two subgroups were created according to the left ventricle ejection fraction values (LVEF ≤ 45% and LVEF > 45%, with 15 and 16 patients respectively). A simultaneous not-invasive brachial blood pressure was obtained. Results The W1 was significantly linearly correlated with the echocardiographic LV dP/dt value (r = 0.41, p 0.02). Both W1 and LV dP/dt correlated significantly with LV ejection fraction. Conclusions Carotid WI evaluation, and specifically its first peak W1, could be reinterpreted as an alternative method to estimate not invasively LV contractility performance. Larger studies are needed to evaluate the relative prognostic role of carotid artery W1 and LV dP/dt in clinical practice. Results LVEF ≤ 45 % (n = 15) LVEF > 45 % (n = 16) p value W1 6.19 +- 3.77 9.3 +- 3.43 0.02 dP/dT 789 +- 329 1244 +- 337 0.0007 Abstract P1806 Figure. Common Carotid Artery eTracking

Production of extra-strong concrete axisymmetric products

The article presents the results of many years of comprehensive research on the new technology of forming extra-strong unreinforced pipes for hydro-engineering construction by vibro-peristaltic hyper-compacting with simultaneous modifying of the concrete mixtures and concrete itself. The regularities of occurrence of a compacted mixture in a column of high-intensity compression and tension zones varying in time, as well as the placement and configuration of the filtration fields of the formwork forms, taking into account the type and diameter of the holes preventing their blockage in the molding process, are given. As a result of experimental theoretical and industrial research, the scientific basis for the production of highly durable concrete has been developed. Technological bases of its production in axisymmetric products, as well as a new installation for molding concrete unreinforced pipes by vibro-peristaltic pressing, which is protected by copyright certificate and patent of the Republic of Uzbekistan. The installation is intended for forming low-pressure and free-flow pipes with a nominal diameter from 500 to 1500 mm and a length of up to 2000 mm. The purpose of this article is to share the results of research, experience to accelerate the widespread introduction of new technology.

Assessing structure and function of myelin in cervical spondylotic myelopathy

Purpose:To assess the extent of demyelination in cervical spondylotic myelopathy (CSM) using myelin water imaging (MWI) and electrophysiologic techniques.Methods:Somatosensory evoked potentials (SSEPs) and MWI were acquired in 14 patients with CSM and 18 age-matched healthy controls. MWI was performed on a 3.0T whole body magnetic resonance scanner. Myelin water fraction (MWF) was extracted for the dorsal columns and whole cord. SSEPs and MWF were also compared with conventional MRI outcomes, including T2 signal intensity, compression ratio, maximum spinal cord compression (MSCC), and maximum canal compromise (MCC).Results:Group analysis showed marked differences in T2 signal intensity, compression ratio, MSCC, and MCC between healthy controls and patients with CSM. There were no group differences in MWF and SSEP latencies. However, patients with CSM with pathologic SSEPs exhibited reduction in MWF (p < 0.05). MWF was also correlated with SSEP latencies.Conclusion:Our findings provide evidence of decreased myelin content in the spinal cord associated with impaired spinal cord conduction in patients with CSM. While conventional MRI are of great value to define the extent of cord compression, they show a limited correlation with functional deficits (i.e., delayed SSEPs). MWI provides independent and complementary readouts to spinal cord compression, with a high specificity to detect impaired conduction.

Optimization Model Estimates of Trunk Muscle Forces Do Not Correlate with EMG Activity of Females as Well as Males

Biomechanical optimization models are often used to estimate muscular and intervertebral disc forces during physical exertions. The purpose of this study was to determine whether an optimization-based biomechanical model predicts torso muscular activity of males and females equally well. The Minimum Intensity Compression (MIC) model, which has been extensively applied in industrial ergonomic task analysis, was used to estimate muscle forces for 3D moments. Participants (6 M, 6 F) performed 18 isometric exertions resisting 3D L3/L4 moments while electromyographic (EMG) activity was recorded for 8 muscles. Overall, model force estimates correlated better with male EMG activity (R2= 0.43) than with female EMG activity (R2= 0.33). Model force estimates of 4 muscles (LRA, RRA, REO, and RES) correlated better with male EMG activity than with female EMG. We conclude that trunk muscle forces estimated by current biomechanical modeling do not correlate equally well to male and female EMG activity. Future research needs to address validation or improvement of biomechanical trunk models for females.

Predicted Muscular Activity for Varying Inputs to Optimization-Based Biomechanical Trunk Models

The Minimum Intensity Compression (MIC) model developed by Bean, Chaffin, and Schultz (1988) and the Sum of the Cubed Intensities (SCI) model developed by Crowninshield and Brand (1981) have been used to predict trunk muscle forces during external loads. The models require muscle geometries (moment arms, lines of action, and cross-sectional areas) as inputs. This paper reports on a computer simulation conducted to evaluate the changes in trunk muscle forces predicted by the MIC and SCI models with changes in inputs. Two muscle geometries were used for a 10-muscle set one reported by Han, Ann, Goel, Takeuchi, and McGowan (1992) and a second formed by a compilation of several studies. The results indicate that regions of muscle activity and magnitude vary greatly between the models and associated inputs. Muscle EMG data indicating active and inactive loading conditions reported by Lavender, Tsuang, Hafezi, Andersson, Chaffin, and Hughes (1992) are significantly predicted by the model combinations for some right side muscles.