1,720,974 research outputs found
Memristor Platforms for Pattern Recognition Memristor Theory, Systems and Applications
Full text linkIn the last decade a large scientific community has focused on the study of the memristor. The memristor is thought to be by many the best alternative to CMOS technology, which is gradually showing its flaws. Transistor technology has developed fast both under a research and an industrial point of view, reducing the size of its elements to the nano-scale. It has been possible to generate more and more complex machinery and to communicate with that same machinery thanks to the development of programming languages based on combinations of boolean operands. Alas as shown by Moore's law, the steep curve of implementation and of development of CMOS is gradually reaching a plateau. It is clear the need of studying new elements that can combine the efficiency of transistors and at the same time increase the complexity of the operations. Memristors can be described as non-linear resistors capable of maintaining memory of the resistance state that they reached. From their first theoretical treatment by Professor Leon O. Chua in 1971, different research groups have devoted their expertise in studying the both the fabrication and the implementation of this new promising technology. In the following thesis a complete study on memristors and memristive elements is presented. The road map that characterizes this study departs from a deep understanding of the physics that govern memristors, focusing on the HP model by Dr. Stanley Williams. Other devices such as phase change memories (PCMs) and memristive biosensors made with Si nano-wires have been studied, developing emulators and equivalent circuitry, in order to describe their complex dynamics. This part sets the first milestone of a pathway that passes trough more complex implementations such as neuromorphic systems and neural networks based on memristors proving their computing efficiency. Finally it will be presented a memristror-based technology, covered by patent, demonstrating its efficacy for clinical applications. The presented system has been designed for detecting and assessing automatically chronic wounds, a syndrome that affects roughly 2% of the world population, through a Cellular Automaton which analyzes and processes digital images of ulcers. Thanks to its precision in measuring the lesions the proposed solution promises not only to increase healing rates, but also to prevent the worsening of the wounds that usually lead to amputation and death
Device and method for acquisition of medical images for the analysis of ulcers
Full text linkThe present invention relates to the acquisition of medical images of ulcers. More specifically, the present invention relates to a device for acquiring and processing medical images of ulcers and to a method for acquisition of medical images of ulcers
Chua's Constitutive Memristor Relations for Physical Phenomena at Metal-Oxide Interfaces
No full textDespite a considerable number of memristor models of different complexity proposed in the literature, there is an ongoing debate over what kind of memristor model should be universally adopted for exploration of the unique opportunities integrated memristor circuits may offer. Here, we follow Chua's approach, that models for i-v characteristics are devoid of predictive power and that instead a memristor model should be expressed in terms of electric flux φ and total charge q only-independent of any specific driving input. Accordingly, Chua's constitutive memristor relations are constructed explicitly for Williams' famous TiO2 device in terms of q=q(φ). It is shown that this kind of model describes correctly the prevalent physical phenomena at the metal-oxide interfaces and is able to predict without any further parameters or assumptions, the dependence of Vset and Vreset voltages on the particular input voltage wave form. The impact of thermal (memory) effects on device performance is explored in numerical simulations
Live Demonstration: 3D Wound Detection & Tracking System Based on Artificial Intelligence Algorithm
Full text linkEvery year over 2% of the worldwide population (estimated 20 million people between US and Europe) will develop a cutaneous wound during their lifetime experiencing chronic pain, reduced mobility and a high amputation and mortality risk (75% within 5 years). Aging of the population and a sharp rise in the incidence of obesity and chronic diseases such as diabetes are the main drivers of this epidemic that is forecast to grow with a 5-8% rate over the following 5 years. Clinical studies proved that is possible to reduce healing time and the advent of adverse consequences of 50% carrying out a monitoring of the variation of key parameters. Nowadays physicians don’t have access to a precise decision-supporting tool to valuate and monitor healing process and the effectiveness of the delivered treatment. Our solution is called Wound Viewer, a Class 1 medical device able to acquire and automatically process wound images through an artificial intelligence (AI) algorithm providing to the physician fundamental parameters such as area, depth, recognize the tissue composing the wound (example: granular, necrotic) and wound exudate. Wound Viewer has been tested on over 400 patients reaching a measurement accuracy of over 94%
Metodo di classificazione e correlazione tra lo stato patologico della cute e la corrispondente terapia e posologia
Full text linkLa presente invenzione riguarda il campo dell'acquisizione di immagini mediche di ulcere e più specificamente l'acquisizione e l'elaborazione di immagini mediche di ulcere. Più nel dettaglio, la presente invenzione si riferisce alle tecniche di classificazione delle ulcere cutanee per individuare automaticamente la cura appropriata, ovvero la corrispondente terapia e posologia corretta da applicare per ogni singolo caso analizzato. In tale operazione di individuazione della cura appropriata intervengono anche le informazioni sul paziente. I campi di applicazione della presente invenzione spaziano tra la flebologia, la dermatologia, la diabetologia, l'oncologia e tutti gli ambiti afferenti alla vulnologia, ovvero il ramo della medicina che studia le lesioni croniche della cute
Exploring the use of natural zeolite to engineer green therapeutic agents for the advanced treatment of chronic wounds
Full text linkIntroduction
Chronic skin wounds are defined as lesions that fail to heal within 3-4 weeks of treatment, primarily due to persistent inflammation and infection. Despite great efforts have been devoted towards the engineering of anti-inflammatory and anti-bacterial formulations, the effective management of chronic wounds remains a substantial clinical challenge. Consequently, the pursuit of innovative and more efficacious therapeutic strategies has become a critical area of research. In this context, the family of natural zeolites has emerged as a promising alternative to conventional therapeutics. Indeed, owing to their micro- and nano-structured porous nature, zeolites possess excellent ion-exchange and scavenging capabilities, considered to be crucial features in the design of anti-inflammatory and anti-microbial treatments. Additionally, zeolites could also have the potential to actively support the wound healing process by guiding cell behavior, proliferation, migration and differentiation. Moreover, zeolites can be easily extracted from volcanic and sedimentary rocks. Therefore, their intrinsic clinical features together with easy accessibility and abundancy make this inorganic material an optimal candidate as innovative therapeutic agent. Among the various types of zeolites, clinoptilolite was selected in this work for its therapeutic potential in treating chronic wounds. To further enhance its anti-inflammatory features particular attention has been focused on the functionalization of the powder through the implementation of a double step water-based reaction, finally leading to the surface exposure of heparin.
Experimental
The clinoptilolite powder (referred to as MANC - Modified and Activated Natural Clinoptilolite) was kindly supplied by an external company (Froximun AG, Germany) and surface functionalized with heparin through a two-step reaction. First, MANC was subjected to silanization with 3-aminopropyltrihetoxysilane (APTES) to expose amino groups. The reaction was optimized by studying the influence of solvent (i.e., water vs. toluene), reaction time (i.e., 3h vs. 24h) and drying process (i.e., room temperature vs. thermal treatment). Then, water-based carbodiimide chemistry was used to graft heparin through the formation of amide bonds between MANC-NH2 and heparin-COOH. The success of functionalization was assessed through Dynamic Light Scattering (DLS), Infrared (IR) spectroscopy, Z-potential measurements and colorimetric assays to quantify grafted molecules. In vitro cell viability and proliferation assays were conducted to study powder cytocompatibility in direct contact with murine fibroblasts, while the anti-inflammatory scavenging action exerted by heparin was quantified by measuring cytokines levels in the media over time. Lastly, a proof-of-concept of minimally invasive powder application was carried out by its embedding in a thermo-responsive hydrogel followed by temperature-controlled injection through needles with various dimensions in a wound-mimicking cavity.
Results and Discussion
The as received MANC powder showed an average hydrodynamic diameter in the range 500-700 nm, a negative surface charge (i.e., Z-potential value approx. -50 mV) due to the exposure of -OH groups and a strong tendency to undergo sedimentation within few minutes after sonication. Powder silanization resulted in increased average hydrodynamic diameters and Z-potential values, confirming the success of APTES grafting, irrespective of adopted reaction parameters. The reaction time (i.e., 3h and 24 h) did not significantly alter the grafting yield. Conversely, solvent selection was found to strongly affect the number of exposed amino groups. More in detail, the superficial charge increased up to -21.35±1.44 mV upon MANC functionalization in anhydrous toluene for 24h, but Z-potential trend inversion to positive values (i.e., +19.68±0.80 mV) was obtained only by using water as solvent. Such results were further confirmed by the colorimetric quantification of amino groups, found to be 7×1019 ± 2×1018 and 1×1020 ± 3×1019 units/gpowder for reactions carried out in toluene and water, respectively. On the other hand, the use of organic solvent resulted in a more stable functionalization coating when the powder was put in contact with fluids, further enhanced by the thermal treatment as final drying step. Regarding water-based carbodiimide mediated heparin grafting, the success of the reaction was confirmed by: IR spectra through the appearance of the peaks at 1635 and 1530 cm-1 ascribed to the C=O and N-H vibrations belonging to the amide bonds; Z-potential measurements giving negative values in accordance with the exposure of negative heparin molecules; increased particle average hydrodynamic diameter and, improved stability of the powder suspension over time. Moreover, the colorimetric quantification of heparin definitely confirmed the grafting, giving functionalization yields approx. equal to 100%. In addition, murine fibroblasts treated with functionalized MANC exhibited high cytocompatibility and improved cell proliferation compared to cells in contact with not-modified MANC. Moreover, preliminary tests showed heparin-grafted powder capability to sequester pro-inflammatory cytokines from the media, thus proving MANC potential as anti-inflammatory drug. Lastly, a proof-of-concept of the feasibility to encapsulate the powder in a thermo-sensitive hydrogel was carried out in its perspective clinical application as therapeutic agent in the form of injectable system or cream to be mini-invasively applied in the wound bed.
Conclusions
Natural zeolites hold significant potential as alternative therapeutic agents for the treatment of chronic wounds owing to their inherent scavenging features. Furthermore, their wide availability, ease of extraction, and the feasibility of functionalization through environmentally friendly chemical processes further enhance their appeal as naturally derived therapeutic materials.
Acknowledgment
R.L. acknowledges financial support from the FSE REACT-EU - PON Ricerca e Innovazione 2014-2020. This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them
Flux–Charge Memristor Model for Phase Change Memory
Full text linkPhase-change memory (PCM) is one of the most promising non-volatile memory technologies and is finding applications in areas such as storage-class memory and emerging non-von Neumann computing systems. Even though powerful physics-based models have been developed for these devices, there is a lack of simple and accurate circuit models to describe these elements. In this brief, we exploit memristor theory to obtain a simple and reliable circuit model based on electrical variables such as charge and flux. This model is based on experimental measurements of PCM devices fabricated in the 90 nm technology node
Memristor cellular automata through belief propagation inspired algorithm
No full textThe development of neuromorphic systems has increased in pace in the past years since the birth of industrial samples of memristors. In addition to developing the general technology, a strong interest in generating new applications for memristive systems is emerging. In this paper we present a Cellular Automata (CA) that works exploiting the Belief Propagation Inspired (BPI) algorithm. To foster and to prove the the equivalence among the two systems a image processing example is introduce
Memristor cellular automata for image pattern recognition and clinical applications
No full textThe development of neuromorphic systems has increased in pace in the past years since the birth of industrial samples of memristors. In addition to developing the general technology, a strong interest in generating new applications for memristive systems is emerging. Cellular automata (CA) can be utilized for biomedical applications, primarily for image processing. Here, we have developed a CA that can be used to improve patient care, through the follow-up and monitoring of patients affected by topic wounds such as cutaneous ulcers
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