Magnetic Nanomaterials

The constant search for innovative magnetic materials increasingly leads to the creation of highly engineered systems built in different forms (films, wires, particles), structured on the nanoscale in at least one spatial direction, and often characterized by the coexistence of two or more phases that are magnetically and/or structurally different. In magnetic systems, the nanometric structural characteristics of the constituent elements, together with the type and strength of the magnetic interactions between them, determine the overall magnetic behavior and can lead to the appearance of unexpected and amazing magnetic phenomena. Indeed, the study of the magnetic properties of nanomaterials continues to arouse great interest for their intriguing fundamental properties and prospective technological applications. This Special Issue contributes to broadening the knowledge on magnetic nanomaterials, demonstrating the breadth and richness of this research field as well as the growing need to address it through an interdisciplinary approach. The papers collected in this book (two reviews and eight regular articles) report cutting-edge studies on the production and characterization of a variety of novel magnetic nanomaterials (nanoparticles, nanocomposites, thin films and multilayers), which have the potential to play a key role in different technologically advanced sectors, such as biotechnology, nanomedicine, energy, spintronics, data storage, and sensors

Comparison of spread spectrum and pulse signal excitation for split spectrum techniques composite imaging

[EN] Ultrasonic imaging of composites was investigated. Glass and carbon fiber reinforced plastic produced by resin transfer molding and prepreg forming were analyzed. In some of the samples air bubbles were trapped during RTM (resin transfer molding) process and interlayer gaps were present in prepreg technology samples. One of the most expected techniques to apply in such case is the Split Spectrum processing. On the other hand such signals require specific processing to reliably reconstruct the temporal position of the defect reflection. Correlation processing can be used for signal compression or Wiener filtering can be applied for spectral content equalisation. Pulse signals are simple to generate, but lack the possibility to alter the signal’s spectrum shape. Spread spectrum signals offer a powerful tool for signal energy over frequency band increase and resolution enhancement. CW (continuous wave) burst has high energy but lacks the bandwidth needed for SSP (spread spectrum processing). The aim of the investigation was to compare the performance of the above signals in case of composite imaging, when various Split Spectrum Processing techniques are used with preceding Wiener processing for spectral content compensation. Resulting composite signals and images obtained are presented. Structural noise removal performance was evaluated as Receiver Operating Characteristics (ROC).This research (acquisition system and spread spectrum signals) was funded by a grant (No. MIP058/2012) from the Research Council of Lithuania. SSP part was supported by PROMETEO 2010/40.Svilainis, L.; Kitov, S.; Rodriguez Martinez, A.; Vergara Domínguez, L.; Dumbrava, V.; Chaziachmetovas, A. (2012). Comparison of spread spectrum and pulse signal excitation for split spectrum techniques composite imaging. IOP Conference Series: Materials Science and Engineering. 42:5-9. https://doi.org/10.1088/1757-899X/42/1/012007S594

Intracellular delivery by membrane disruption: Mechanisms, strategies, and concepts

© 2018 American Chemical Society. Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo typesñYsmall molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery

Advances in Bioengineering

The technological approach and the high level of innovation make bioengineering extremely dynamic and this forces researchers to continuous updating. It involves the publication of the results of the latest scientific research. This book covers a wide range of aspects and issues related to advances in bioengineering research with a particular focus on innovative technologies and applications. The book consists of 13 scientific contributions divided in four sections: Materials Science; Biosensors. Electronics and Telemetry; Light Therapy; Computing and Analysis Techniques

Intravascular Detection of Microvessel Infiltration in Atherosclerotic Plaques: An Intraluminal Extension of Acoustic Angiography

Cardiovascular disease is the leading cause of death worldwide, surpassing both stroke and cancer related mortality with 17.5 million deaths in 2014 alone. Atherosclerosis is the build-up of fatty deposits within arteries and is responsible for the majority of cardiovascular related deaths. Over the past decade, research in atherosclerosis has identified that a key limitation in the appropriate management of the disease is detecting and identifying dangerous fatty plaque build-ups before they dislodge and cause major cardiovascular events, such as embolisms, stroke, or myocardial infarctions. It has been noted that plaques vulnerable to rupture have several key features that may be used to distinguish them from asymptomatic plaques. One key identifier of a dangerous plaque is the presence of blood flow within the plaque itself since this is an indicator of growth and instability of the plaque. Recently, a superharmonic imaging method known as “acoustic angiography” has been shown to resolve microvasculature with unprecedented quality and could be a possible method of detecting blood vessel infiltration within these plaques. This dissertation describes the material and methods used to move the application of “acoustic angiography” to a reduced form factor typical of intravascular catheters and to demonstrate its ability to detect microvasculature. The implementation of this approach is described in terms of the contrast agents used to generate superharmonic signals, the dual-frequency transducers to image them, and the hardware needed to operate them in order to establish how these design choices can impact the quality of the images produced. Furthermore, this dissertation demonstrates how image processing methods such as adaptive windowing or automated sound speed correction can further enhance image quality of vascular targets. The results of these chapters show how acoustic angiography may be optimized using engineering considerations both in signal acquisition and post processing. Overall, these studies demonstrate that acoustic angiography can be performed using a catheter-deployable dual-frequency transducer to detect microvasculature through superharmonic imaging methods.Doctor of Philosoph

Pulsed Laser Manipulation of Cells Decorated by Plasmonic Nanoparticles

Au cours des dernières décennies, la thérapie cellulaire a suscité un intérêt considérable dans les domaines de la recherche biomédicale et théranostique. Une large gamme d’applications biomédicales a obtenu des avantages fructueux par une manipulation directe de cellules (cellules seuls ou groupes de cellules individuelles) en contrôlant la concentration de nanoparticules plasmoniques fonctionnelles et de lasers à impulsions. Cependant, tous ces protocoles de transfection, accompagnés d’une efficacité et d’une toxicité de transfection cellulaire variées, sont applicables pour une condition spécifique. Ainsi, l’optoporation doit être explorée, optimisée et généralisée pour un large éventail de thérapies cellulaires délicates et complexes par le laser. Un suivi en temps réel des cellules optoporées révèle les mécanismes impliqués dans une transfection réussie sans induire de cytotoxicité. Dans cette thèse, le laser pulsé nanoseconde (532 nm) utilisé pour optoporer une seule cellule cancéreuse humaine du sein (MDA-MB-231) montre clairement les effets des fluences du laser pulsé. L’optoporation intériorise les molécules exogènes (Iodure de Propidium) dans l’intervalle fonctionnel compris entre 0.3 et 0.7 J/cm2 sans provoquer d’effet secondaire (confirmé par Calcein AcetoxyMethyl). La position du faisceau détermine clairement dans quels compartiments subcellulaires les molécules exogènes à intérioriser avec précision. Le faisceau laser focalisé près du noyau dirige intensément l’Iodure de Propidium (PI) pour qu’il réagisse avec les nucléotides cellulaires, alors que pour le faisceau focalisé loin du noyau, le PI se déverse à peine dans le site d’action. Ce protocole d’optoporation, indiquant le rôle critique des nanoparticules plasmoniques liées, nécessite un faisceau laser dirigé vers la position de la nanoparticule plasmonique sur la membrane cellulaire. L’éclairage latéral par LED développé ici visualise simplement la nanoparticule plasmonique liée sur la membrane cellulaire dans une grande zone. Par la suite, un laser femtoseconde dans le proche infrarouge (800 nm) est également utilisé pour optoporer des cellules de lymphocyte T humaines supersensibles (Jurkat) avec un taux de survie négligeable après une exposition de courte durée à une fluence relativement élevée (252 mJ/cm2). En explorant plusieurs fluences laser et durées d’irradiation, nous obtenons donc une gamme applicable de fluences laser (63 à 71 mJ/cm2) et de temps d’irradiation (10 ms) pour l’optoporation de cellules de Jurkat liées à des nanoparticules plasmoniques sans réduire leur viabilité cellulaire. Ces résultats fondamentaux indiquent comment effectuer une optoporation réussie en ajustant les paramètres du laser (fluence, durée d’irradiation, position, etc.) sur différentes lignées cellulaires afin d’atteindre une haute transfection pour une large gamme d’applications biomédicales.----------ABSTRACT In the last decades, cell therapy has attracted tremendous interests in biomedical and theranostic research fields. A wide range of biomedical applications has gained fruitful benefits by a direct manipulation of cells (whether single cell or bunch of individual cells) by controlling the concentration of functional plasmonic nanoparticles and pulsed lasers. However, all these transfection protocols, accompanied by a varied cellular transfection efficiency and toxicity, are applicable for a specific condition. Thus, the optoporation needs to be explored, optimized, and generalized for a broad range of delicate and complex laser mediated cell therapies. A real-time monitoring of the optoporated cells reveals mechanisms involved in a successful transfection without inducing cytotoxicity. In this thesis, the nanosecond pulsed laser (532 nm) used to optoporate a single adherent human breast cancer cell (MDA-MB-231) clearly shows effects of the pulsed laser fluences. The optoporation internalizes the exogenous molecules (Propidium Iodide) at the functional range between 0.3 to 0.7 J/cm2 without causing a side effect (confirmed by Calcein AcetoxyMethyl). The beam pointing location clearly determines in which subcellular compartments the exogenous molecules to be internalized precisely. The laser beam localized close to the nucleus intensively directs the Propidium Iodide there to react with cellular nucleotides, whereas the beam far away from the nucleus barely fluxes into the site of action. This optoporation protocol, indicates the critical role of the bound plasmonic nanoparticles, is required a laser beam to be directed to the position of the plasmonic nanoparticle on the cellular membrane. The lateral LED illumination developed here simply visualizes the bound plasmonic nanoparticle on the cell membrane in a large area. Afterward, near-infrared femtosecond laser (800 nm) is also employed to optoporate supersensitive human T lymphocyte cells (Jurkat) with a negligible survival rate after a short time exposure to a relatively high fluence (252 mJ/cm2). Exploring several laser fluences and irradiation durations, we therefore obtain an applicable range of laser fluences (63 to 71 mJ/cm2) and irradiation time (10 ms) for the optoporation of plasmonic nanoparticles bound Jurkat cells without reducing their cell viability. These fundamental results indicate how to perform a successful optoporation by adjusting laser parameters (i.e., fluence, irradiation duration, position, etc.) on different cell lines in order to achieve high transfection for a wide range of biomedical applications

Cancer Nanomedicine

This special issue brings together cutting edge research and insightful commentary on the currentl state of the Cancer Nanomedicine field

Effects of errorless learning on the acquisition of velopharyngeal movement control

Session 1pSC - Speech Communication: Cross-Linguistic Studies of Speech Sound Learning of the Languages of Hong Kong (Poster Session)The implicit motor learning literature suggests a benefit for learning if errors are minimized during practice. This study investigated whether the same principle holds for learning velopharyngeal movement control. Normal speaking participants learned to produce hypernasal speech in either an errorless learning condition (in which the possibility for errors was limited) or an errorful learning condition (in which the possibility for errors was not limited). Nasality level of the participants’ speech was measured by nasometer and reflected by nasalance scores (in %). Errorless learners practiced producing hypernasal speech with a threshold nasalance score of 10% at the beginning, which gradually increased to a threshold of 50% at the end. The same set of threshold targets were presented to errorful learners but in a reversed order. Errors were defined by the proportion of speech with a nasalance score below the threshold. The results showed that, relative to errorful learners, errorless learners displayed fewer errors (50.7% vs. 17.7%) and a higher mean nasalance score (31.3% vs. 46.7%) during the acquisition phase. Furthermore, errorless learners outperformed errorful learners in both retention and novel transfer tests. Acknowledgment: Supported by The University of Hong Kong Strategic Research Theme for Sciences of Learning © 2012 Acoustical Society of Americapublished_or_final_versio