Functional Magnetic Resonance Imaging of Motor Cortex Activation in Schizophrenia

이효종,Adrian Preda,Judith M. Ford,Daniel H. Mathalon,David B. Keator,Theo G.M. van Erp,Jessica A. Turner,Steven G. Potkin 대한의학회 2015 Journal of Korean medical science Vol.30 No.5

Previous fMRI studies of sensorimotor activation in schizophrenia have found in some cases hypoactivity, no difference, or hyperactivity when comparing patients with controls; similar disagreement exists in studies of motor laterality. In this multi-site fMRI study of a sensorimotor task in individuals with chronic schizophrenia and matched healthy controls, subjects responded with a right-handed finger press to an irregularly flashing visual checker board. The analysis includes eighty-five subjects with schizophrenia diagnosed according to the DSM-IV criteria and eighty-six healthy volunteer subjects. Voxel-wise statistical parametric maps were generated for each subject and analyzed for group differences; the percent Blood Oxygenation Level Dependent (BOLD) signal changes were also calculated over predefined anatomical regions of the primary sensory, motor, and visual cortex. Both healthy controls and subjects with schizophrenia showed strongly lateralized activation in the precentral gyrus, inferior frontal gyrus, and inferior parietal lobule, and strong activations in the visual cortex. There were no significant differences between subjects with schizophrenia and controls in this multi-site fMRI study. Furthermore, there was no significant difference in laterality found between healthy controls and schizophrenic subjects. This study can serve as a baseline measurement of schizophrenic dysfunction in other cognitive processes.

Video-Based Point-Cloud-Compression Standard in MPEG: From Evidence Collection to Committee Draft [Standards in a Nutshell]

Jang, Euee S.,Preda, Marius,Mammou, Khaled,Tourapis, Alexis M.,Kim, Jungsun,Graziosi, Danillo B.,Rhyu, Sungryeul,Budagavi, Madhukar IEEE 2019 IEEE signal processing magazine Vol.36 No.3

<P>The widespread adoption of new 3D sensor and authoring technologies has made it possible to capture 3D scenes and models in real time with decent visual quality. As an example, Microsoft's Kinect and Apple's PrimeSense technology are now being used in a wide variety of interactive 3D mobile applications, including gaming and augmented reality applications. The latest smartphones are equipped with multiple cameras, which can be readily used to generate depth images. Some of the latest smartphones also include depth-ranging sensors that can be used for 3D model generation. Light-based detection and ranging (lidar) technologies are yet another field where 3D depth acquisition is important. Realtime 3D scenery detection and ranging has become an important issue for the emerging field of autonomous navigation and driving applications.</P>

The Implications of Increasing Temperature due to Climate Change for Asphalt Concrete Performance and Pavement Design

Sarayoot Kumlai,Peerapong Jitsangiam,Preda Pichayapan 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.4

The dynamic moduli have been recently introduced and effectively used to express the intrinsic behaviour of the viscoelasticity of an asphalt concrete material across a given range of temperatures and frequencies. Those can generally be represented in a form of the master curve. This study investigated the dynamic moduli of Western Australian (WA) asphalt mixes. In addition, the study modified the dynamic modulus predictive equation of the national cooperative highway research program (NCHRP) project 1-37A to suit WA conditions. Furthermore, in this study, the effect of increased temperatures due to climate change upon flexible road pavement was investigated through the pavement design exercise using WA as the study area. To determine the effective dynamic modulus (|E*|eff), temperature and historical climate data were sourced from a Perth Airport Station to conduct a pavement design exercise. This data covered a 20-year period, a typical asphalt pavement design life. The allowable number of cycles (of traffic) to failure (Nf) under four different pavement design scenarios was then calculated based on this |E*|eff to examine of an increase in temperature potentially resulting from climate change effects. The results of the examination showed that once an increase in temperature due to climate change was taken into account, Nf could be decreased by approximately six million repetitions. This equals a shorter pavement life or design period of around four years compared to a result of the original design, which does not consider the increase in temperature resulting from climate change.

Beginning of a New Standard: Internet of Media Things

( Sang-kyun Kim ),( Nevadita Sahu ),( Marius Preda ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.11

Recently, Internet of Things (IoT) drives a large variety of research, development, and new type of markets. All type of devices and sensors will be part of the Internet of Things and will be able to communicate not only plain data, but also audio-visual, olfactory, and haptic media data. In addition, as the devices and sensors getting smarter, it is highly probable that they can process acquired media and metadata to extract higher level of information (e.g., semantics). To support such enhanced functionalities, ISO/IEC SC29 WG11 (MPEG) starts a new standard project, ISO/IEC 23093, called Internet of Media Things (IoMT) to provide standard data formats and APIs for media things. This paper presents the standardization activities of IoMT focusing on explaining terms, standard scopes, and major media things with their use cases. One of the use cases, an IoT system for a blind pedestrian navigation assistance, is evaluated to prove its effectiveness.

75. Disrupted Network Cross Talk, Hippocampal Dysfunction, and Hallucinations in Schizophrenia

Hare, S.,Law, A.,Ahmadi, A.,Damaraju, E.,Belger, A.,Bustillo, J.,Lee, H. J.,Mathalon, D.,Mueller, B.,Preda, A. Oxford University Press 2017 Schizophrenia bulletin Vol.43 No.suppl1

Bioreactor Conditioning of Valve Scaffolds Seeded Internally with Adult Stem Cells

Allison Kennamer,Leslie Sierad,Richard Pascal,Nicholas Rierson,Christopher Albers,Marius Harpa,Ovidiu Cotoi,Lucian Harceaga,Peter Olah,Preda Terezia,Agneta Simionescu,Dan Simionescu 한국조직공학과 재생의학회 2016 조직공학과 재생의학 Vol.13 No.5

The goal of this study was to test the hypothesis that stem cells, as a response to valve-specific extracellular matrix “niches” and mechanical stimuli, would differentiate into valvular interstitial cells (VICs). Porcine aortic root scaffolds were prepared by decellularization. After verifying that roots exhibited adequate hemodynamics in vitro, we seeded human adipose-derived stem cells (hADSCs) within the interstitium of the cusps and subjected the valves to in vitro pulsatile bioreactor testing in pulmonary pressures and flow conditions. As controls we incubated cell-seeded valves in a rotator device which allowed fluid to flow through the valves ensuring gas and nutrient exchange without subjecting the cusps to significant stress. After 24 days of conditioning, valves were analyzed for cell phenotype using immunohistochemistry for vimentin, alpha-smooth muscle cell actin (SMA) and prolyl-hydroxylase (PHA). Fresh native valves were used as immunohistochemistry controls. Analysis of bioreactor-conditioned valves showed that almost all seeded cells had died and large islands of cell debris were found within each cusp. Remnants of cells were positive for vimentin. Cell seeded controls, which were only rotated slowly to ensure gas and nutrient exchange, maintained about 50% of cells alive; these cells were positive for vimentin and negative for alpha-SMA and PHA, similar to native VICs. These results highlight for the first time the extreme vulnerability of hADSCs to valve-specific mechanical forces and also suggest that careful, progressive mechanical adaptation to valve-specific forces might encourage stem cell differentiation towards the VIC phenotype.

Surface Analysis, Microstructural, Mechanical and Electrochemical Properties of New Ti-15Ta-5Zr Alloy

Cora Vasilescu,Silviu Iulian Drob,Petre Osiceanu,Paula Drob,Jose Maria Calderon Moreno1,Silviu Preda,Steliana Ivanescu,Ecaterina Vasilescu 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.2

This paper describes the synthesis of a novel Ti-15Ta-5Zr alloy with an  + β stable, homogeneous, biphasicmicrostructure (by optical microscopy, X-ray diffraction and scanning electron microscopy) and the determinationof its mechanical properties, hardness and a Young’s modulus of 42.2 GPa. The alloy passive film compositionand thickness were analyzed by X-ray photoelectron spectroscopy; a thick, compact native passive filmcontaining the protective oxides of all constituent elements (TiO2, Ta2O5, ZrO2) was identified. The electrochemicalparameters confirmed a nobler behaviour and a more capacitive, resistant passive film on thealloy surface compared to Ti and other existing implant alloys; these facts are due to the alloying elements that,by their oxides stabilize and reinforce the alloy passive film. This passive film thickened in time, which increased itsprotective capacity. The new alloy had no susceptibility to galvanic or local corrosion. Ti-15Ta-5Zr alloyis recommended as an advanced orthopaedic implant material.

Modality-Dependent Impact of Hallucinations on Low-Frequency Fluctuations in Schizophrenia

Hare, S. M.,Ford, J. M.,Ahmadi, A.,Damaraju, E.,Belger, A.,Bustillo, J.,Lee, H. J.,Mathalon, D. H.,Mueller, B. A.,Preda, A. Oxford University Press 2017 Schizophrenia bulletin Vol.43 No.2

<P>Prior resting-state functional magnetic resonance imaging (fMRI) analyses have identified patterns of functional connectivity associated with hallucinations in schizophrenia (Sz). In this study, we performed an analysis of the mean amplitude of low-frequency fluctuations (ALFF) to compare resting state spontaneous low-frequency fluctuations in patients with Sz who report experiencing hallucinations impacting different sensory modalities. By exploring dynamics across 2 low-frequency passbands (slow-4 and slow-5), we assessed the impact of hallucination modality and frequency range on spatial ALFF variation. Drawing from a sample of Sz and healthy controls studied as part of the Functional Imaging Biomedical Informatics Research Network (FBIRN), we replicated prior findings showing that patients with Sz have decreased ALFF in the posterior brain in comparison to controls. Remarkably, we found that patients that endorsed visual hallucinations did not show this pattern of reduced ALFF in the back of the brain. These patients also had elevated ALFF in the left hippocampus in comparison to patients that endorsed auditory (but not visual) hallucinations. Moreover, left hippocampal ALFF across all the cases was related to reported hallucination severity in both the auditory and visual domains, and not overall positive symptoms. This supports the hypothesis that dynamic changes in the ALFF in the hippocampus underlie severity of hallucinations that impact different sensory modalities.</P>

Disrupted network cross talk, hippocampal dysfunction and hallucinations in schizophrenia

Hare, Stephanie M.,Law, Alicia S.,Ford, Judith M.,Mathalon, Daniel H.,Ahmadi, Aral,Damaraju, Eswar,Bustillo, Juan,Belger, Aysenil,Lee, Hyo Jong,Mueller, Bryon A.,Lim, Kelvin O.,Brown, Gregory G.,Preda Elsevier 2018 SCHIZOPHRENIA RESEARCH Vol.199 No.-

<P><B>Abstract</B></P> <P>Hallucinations characterize schizophrenia, with approximately 59% of patients reporting auditory hallucinations and 27% reporting visual hallucinations. Prior neuroimaging studies suggest that hallucinations are linked to disrupted communication across distributed (sensory, salience-monitoring and subcortical) networks. Yet, our understanding of the neurophysiological mechanisms that underlie auditory and visual hallucinations in schizophrenia remains limited.</P> <P>This study integrates two resting-state functional magnetic resonance imaging (fMRI) analysis methods – amplitudes of low-frequency fluctuations (ALFF) and functional network connectivity (FNC) – to explore the hypotheses that (1) abnormal FNC between salience and sensory (visual/auditory) networks underlies hallucinations in schizophrenia, and (2) disrupted hippocampal oscillations (as measured by hippocampal ALFF) beget changes in FNC linked to hallucinations. Our first hypothesis was supported by the finding that schizophrenia patients reporting hallucinations have higher FNC between the salience network and an associative auditory network relative to healthy controls. Hippocampal ALFF was negatively associated with FNC between primary auditory cortex and the salience network in healthy subjects, but was positively associated with FNC between these networks in patients reporting hallucinations. These findings provide <I>indirect</I> support favoring our second hypothesis. We suggest future studies integrate fMRI with electroencephalogram (EEG) and/or magnetoencephalogram (MEG) methods to <I>directly probe</I> the temporal relation between altered hippocampal <I>oscillations</I> and changes in cross-network functional communication.</P>