Effect of connectivity measures on the identification of brain functional core network at rest

Magneto/Electro-encephalography (M/EEG) source connectivity is an emergent tool to identify brain networks with high time/space resolution. Here, we aim to identify the brain core network (s-core decomposition) using dense-EEG. We also evaluate the effect of the functional connectivity methods used and more precisely the effect of the correction for the so-called source leakage problem. Two connectivity measures were evaluated: the phase locking value (PLV) and phase lag index (PLI) that supposed to deal with the leakage problem by removing the zero-lag connections. Both methods were evaluated on resting state dense-EEG signals recorded from 19 healthy participants. Core networks obtained by each method was compared to those computed using fMRI from 487 healthy participants at rest (from the Human Connectome Project - HCP). The correlation between networks obtained by EEG and fMRI was used as performance criterion. Results show that PLV networks are closer to fMRI networks with significantly higher correlation values with fMRI networks, than PLI networks. Results suggest caution when selecting the functional connectivity methods and mainly methods that remove the zero-lag connections as it can severely affect the network characteristics. The choice of functional connectivity measure is indeed crucial not only in cognitive neuroscience but also in clinical neuroscience.

P902 Abnormal diastolic function in patients with transfusion dependant thalassemia major

Aim and Background

Cardiac complications secondary to iron deposition are the commonest cause of death in patients with beta thalassemia major (TM) and can cause various abnormalities. The aim of this study was to assess the diastolic function in patients with transfusion dependant TM and compare with normal controls.

Methods

This was a retrospective study involving patients with transfusion dependant TM , on chelation therapy who had a MRI T2* and a transthoracic echocardiogram during the preceeding 6 months. We compared the findings with those from normal controls. We also correlated the echo findings with the MRI T2* values.

Results

Patients with TM (n = 92, 45% male, mean age 26+ 6 years), with median MRI T2* of 32 (18-39) and normal LV function had signs of diastolic dysfunction as compared to normal controls (41% male, mean age 25 + 6 years) with E/E’ at 6.6 + 1.6 vs 5.5 +1.2 (p < 0.001) and altered pulmonary vein s/d ratio (0.88 + 0.30 vs 1.04 +0.42 for controls, p = 0.02)even in the presence of normal LV systolic function (Ejection fraction 61+ 7% vs 3.4% for controls). There was no difference in the other dimensions. The E/A ratio also corelated well with the MRI T2* (spearmans correlation rho -0.226 p 0.04). There were no other significant correlations between either the MRI T2* or myocardial Iron concentration and any of the other echo parameters

Conclusion

In patients with TM signs of diastolic dysfunction appear before LV systolic dysfunction and may be used to monitor these patients in absence of MRI facilities.

Echo findings in thalassemia Controls (n= 53) Thalassemia Major (n = 92) P value Sex Male Female 22 (41%) 31(59%) 42(45%) 50(55%) 0.5 Mitral E 0.84 + 0.16 1.01 + 0.16 <0.001 Mitral A 0.47 +0.11 0.55 +0.16 <0.001 E/A 1.85 +0.52 1.98 + 0.71 0.24 TDseptal 13.1 + 2.6 13.2 + 3.4 0.9 TDlateral 17.1+ 3.3 17.3 +4.1 0.7 E/E’ 5.5 +1.2 6.6 + 1.6 <0.001 PVs/d 1.04 + 0.41 0.88 +0.30 0.02 TD= tissue doppler; PV- pulmonary vein

A passive damping device for suppressing acoustic pressure pulsations: The infinity tube

Acoustic pressure pulsations in piping systems can cause detrimental damage and failure of industrial components. Both the acoustic resonance and the traveling wave phenomena are of concern for industrial piping systems and there is a need to study passive damping devices and their implementation into these systems. However, there is a challenge associated with manufacturing and installation of such devices as they may be cumbersome. Therefore, the infinity tube (IT) damping device has been presented here to provide a simplified device geometry which can be easily manufactured and implemented into piping systems. A theoretical equation for the transmission loss spectra of the IT device and the frequencies of resonance have been derived as a tool for designers. Additionally, the experimental investigation has shown a considerable increase in acoustic attenuation in comparison to the conventional Herschel-Quincke device due to the significantly shorter length which the IT device can be constructed from. Acoustic pressure and phase angle measurements have elucidated that the fundamental acoustic mode of an open-open pipe can be formed within the IT device. Moreover, a parametric study is presented which has clarified practical considerations required for implementation of the IT device into piping systems for suppressing pressure pulsation.

Co/Pd-Based synthetic antiferromagnetic thin films on Au/resist underlayers: towards biomedical applications

Thin film stacks consisting of multiple repeats M of synthetic antiferromagnetic (SAF) [Co/Pd]N/Ru/[Co/Pd]N units with perpendicular magnetic anisotropy were explored as potential starting materials to fabricate free-standing micro/nanodisks, which represent a promising candidate system for theranostic applications. The films were directly grown on a sacrificial resist layer spin-coated on SiOx/Si(100) substrates, required for the preparation of free-standing disks after its dissolution. Furthermore, the film stack was sandwiched between two Au layers to allow further bio-functionalization. For M ≤ 5, the samples fulfill all the key criteria mandatory for biomedical applications, i.e., zero remanence, zero field susceptibility at small fields and sharp switching to saturation, together with the ability to vary the total magnetic moment at saturation by changing the number of repetitions of the multi-stack. Moreover, the samples show strong perpendicular magnetic anisotropy, which is required for applications relying on the transduction of a mechanical force through the micro/nano-disks under a magnetic field, such as the mechanical cell disruption, which is nowadays considered a promising alternative to the more investigated magnetic hyperthermia approach for cancer treatment. In a further step, SAF microdisks were prepared from the continuous multi-stacks by combining electron beam lithography and Ar ion milling, revealing similar magnetic properties as compared to the continuous films.

Hepatocellular carcinoma response to transcatheter arterial chemoembolisation using automatically generated pre-therapeutic tumour volumes by a random forest-based segmentation protocol

AIM

To demonstrate the feasibility of correlating pre-therapeutic volumes and residual liver volume (RLV) with clinical outcomes: time to progression (TTP) and overall survival (OS) in hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolisation (TACE).

MATERIALS AND METHODS

TTP was calculated from a database of 105 patients, receiving first-line treatment with TACE. TTP cut-off for stratifying patients into responders and non-responders was 28 weeks. Pre-treatment tumour and liver volumes were correlated with the TTP and OS following treatment. Univariate cox-regression model was used to assess whether these volumes could predict TTP and/or OS. Kaplan-Meier analysis with log-rank test was used to compare the TTP between high and low volume groups for viable, necrotic, and total tumour. Kaplan-Meier analysis was performed comparing the OS of 10 patients with the longest TTP (mean=122 weeks) in the responder group and 10 patients with the shortest TTP (mean=7 weeks) in the non-responder group.

RESULTS

HCC in high tumour volume groups had a shorter TTP than lesions in low tumour volume groups (p=0.05, p=0.04, p=0.02, for enhancing, non-enhancing, total tumour groups, respectively). A negative (correlation coefficient [CC] 0.3) linear correlation between TTP and tumour volumes, and a positive linear correlation between TTP and residual liver volumes were also demonstrated (CC 0.3). Patients with the longest TTP had a higher OS than with the shortest TTP (p=0.03).

CONCLUSION

This demonstrates the feasibility of predicting treatment response of HCC to TACE using volumetric measurements of pre-treatment lesion and the feasibility of correlating RLV with TACE outcome data in HCC patients.

The ESC ACCA EAPCI EORP acute coronary syndrome ST-elevation myocardial infarction registry

Aims 

The Acute Cardiac Care Association (ACCA)–European Association of Percutaneous Coronary Intervention (EAPCI) Registry on ST-elevation myocardial infarction (STEMI) of the EurObservational programme (EORP) of the European Society of Cardiology (ESC) registry aimed to determine the current state of the use of reperfusion therapy in ESC member and ESC affiliated countries and the adherence to ESC STEMI guidelines in patients with STEMI.

Methods and results 

Between 1 January 2015 and 31 March 2018, a total of 11 462 patients admitted with an initial diagnosis of STEMI according to the 2012 ESC STEMI guidelines were enrolled. Individual patient data were collected across 196 centres and 29 countries. Among the centres, there were 136 percutaneous coronary intervention centres and 91 with cardiac surgery on-site. The majority of centres (129/196) were part of a STEMI network. The main objective of this study was to describe the demographic, clinical, and angiographic characteristics of patients with STEMI. Other objectives include to assess management patterns and in particular the current use of reperfusion therapies and to evaluate how recommendations of most recent STEMI European guidelines regarding reperfusion therapies and adjunctive pharmacological and non-pharmacological treatments are adopted in clinical practice and how their application can impact on patients’ outcomes. Patients will be followed for 1 year after admission.

Conclusion 

The ESC ACCA-EAPCI EORP ACS STEMI registry is an international registry of care and outcomes of patients hospitalized with STEMI. It will provide insights into the contemporary patient profile, management patterns, and 1-year outcome of patients with STEMI.

Prevalence and predictors of lower urinary tract symptoms in Pakistani men: A cross-sectional study

Objective:

The purpose of this study was to investigate the prevalence and severity of the condition of lower urinary tract symptoms in Pakistani men, determine its predictors and assess its impact on the quality of life.

Methods:

A cross-sectional, population-based study was conducted among men aged 30 years and over in three districts of Punjab province, Pakistan. The modified Urdu version of the International Prostate Symptom Score was used to assess the prevalence and severity of lower urinary tract symptoms. Individuals with total symptom score ⩾8 were considered as having lower urinary tract symptoms. The data were analysed using SPSS version 22. The chi-square test and Mann-Whitney U test were used to assess the difference among categorical and continuous variables, respectively. Moreover, binary logistic regressions were performed to determine the predictors of lower urinary tract symptoms.

Results:

The overall prevalence of lower urinary tract symptoms in our sample was 33.7%. The frequency of individuals having mild, moderate and severe lower urinary tract symptoms was 66.3, 30.3 and 3.4%, respectively. Storage symptoms were more common than voiding symptoms (35.6% vs 28.2%, respectively). Increasing age (one-decade interval age stratum), higher education levels, working status (currently not working), smoking, hypertension, diabetes and renal impairment were positive predictors of lower urinary tract symptoms. Moreover, the condition of lower urinary tract symptoms was associated with a significant reduction in an individual’s quality of life.

Conclusion:

Around one-third of adult Pakistani men suffer from clinically relevant urinary symptoms, with lower urinary tract symptoms sufferers having poor quality of life as compared to non-sufferers. We recommend that the aging population should be made aware of conventional measures to mitigate mild urinary symptoms affecting their routine activities. Level of evidence: 2c

Control rod material effect on safety parameters of research reactors

Control rods provide adjustable manipulation of reactivity and prevent fission reaction from accelerating beyond control. In this paper, the Monte Carlo Code, MCNP6 was used to study the effect of using various control rod materials on the main safety parameters of a typical plate type material test research reactor. Three types of control rod materials were considered, Ag-In-Cd, B4C, and Hafnium. Parameters investigated are reactivity worth, excess reactivity and shutdown margin of absorber materials. The model was used to evaluate the effect of various materials on the flux and power shaping of the core. The resulting multiplication factor for this study was compared with previous work and found acceptable. It was found that boron carbide has the largest effect on safety parameters, as well as flux and power distribution.