What can we learn about controlling a system solely from its underlying network structure? Here we adapt a recently developed framework for control of networks governed by a broad class of nonlinear ...dynamics that includes the major dynamic models of biological, technological, and social processes. This feedback-based framework provides realizable node overrides that steer a system toward any of its natural long-term dynamic behaviors, regardless of the specific functional forms and system parameters. We use this framework on several real networks, identify the topological characteristics that underlie the predicted node overrides, and compare its predictions to those of structural controllability in control theory. Finally, we demonstrate this framework’s applicability in dynamic models of gene regulatory networks and identify nodes whose override is necessary for control in the general case but not in specific model instances.
Zinc oxide’s (ZnO) physical and chemical properties make it a viable and extremely attractive compound to use in a variety of nanotechnology applications. Some of these applications include ...biomedical, energy, sensors, and optics. As the research in ZnO nanostructures continue to grow, it has inspired a whole host of new innovative applications. Complementing its unique chemical qualities, it also has a simple crystal-growth technology and offers significantly lower fabrication costs when compared to other semiconductors used in nanotechnology. Several processes have been developed in order to synthesize high quality ZnO nanostructures—specifically in the case of nanowires. Here we offer a comprehensive review on the growth methods currently employed in research, industry, and academia to understand what protocols are available to meet specific needs in nanotechnology. Methods examined include: the vapor–liquid–solid, physical vapor deposition, chemical vapor deposition, metal–organic chemical vapor deposition, and the hydrothermal-based chemical approach. Each of these methods is discussed and their strengths and weaknesses are analyzed with objective comparison metrics. In addition, we study the current state-of-the-art applications employing ZnO nanostructures at their core. A historical perspective on the evolution of the field and the accompanying literature are also presented.
This paper presents a current controller based on a stationary reference frame implementation of an integrator in the synchronous reference frame called here reduced order generalized integrator ...(ROGI), suitable for three-phase distributed generation systems. The proposed controller is compared with the traditional second-order generalized integrator (SOGI)-based current controller. It is confirmed that, in normal operation conditions, both controllers have similar performance, requiring the ROGI-based controller much less computational burden than the SOGI counterpart. The proposed controller injects sinusoidal currents synchronized with the grid voltage, without requiring any dedicated synchronization algorithm. Three different current injection strategies are realizable with the same controller structure: balanced current injection, constant instantaneous active power injection, and maximum instantaneous active power injection. A state-variable-based control methodology in the discrete-time domain is presented. It ensures the stability and performance of the closed-loop system, even for high-order controllers and large digital signal processor processing delay. Moreover, it is confirmed that the proposed controller works satisfactorily even on faulty grid conditions.
Precision medicine applications supported by nanotechnologies enforce designing a communication interface between in-body nanosensors and external gateways. Such a communication interface will enable ...both a data and a control channel between nanodevices operating within the human body and external control units. In this direction, recent literature focuses on deriving analytic channel models for intra-body links through the human tissues, including the analysis of achievable communication capacities in the terahertz band. A yet missing component, however, is a synchronization module to implement communication schemes in the intra-body link. Such synchronization module will ultimately bound the communication performance regarding the perceived signal to noise ratio (SNR) and bit error rate (BER), for instance. This paper contributes to the state of the art in two directions: (a) evaluating the bounds on the communication performance with the Cramer-Rao lower bound (CRLB) for the synchronization symbol timing offset (STO) and (b) designing a low-complex mechanism to synchronize communication. This analysis considers a communication link between external gateways located on the skin and nanosensor devices flowing in the human vessels. Using envelope and slope detectors, we devise a low-complex solution that relies on the received signal strength (RSS) metric to trigger data emissions. The method estimates the peak of the received RSS metric to ignite communication in the most favorable location, i.e., when the nanosensor is located at the shortest distance in the communication range with external gateways. Our findings illustrate the feasibility of such a low-complex synchronization method. Performance illustrates a BER less than 1×10 −5 for those nanosensors traveling close to the upper vessel wall.
This paper highlights the limitations of the dynamic response of a grid-tied inverter connected through an inductor <inline-formula><tex-math notation="LaTeX">L</tex-math></inline-formula> when it is ...controlled using a proportional+resonant controller. Then, a new resonant current controller structure is proposed. This structure can be used to control the current injected by a grid-tied inverter through an <inline-formula><tex-math notation="LaTeX">L </tex-math></inline-formula> filter. When compared to the classic design, the proposed controller has better transient response, both to current reference and grid voltage changes. This is verified through simulation and experimental results.
Liver diseases represent a critical health problem with 2 million deaths worldwide per year, mainly due to cirrhosis and its complications. Oxidative stress plays an important role in the development ...of liver diseases. In order to maintain an adequate homeostasis, there must be a balance between free radicals and antioxidant mediators. Nuclear factor erythroid 2-related factor (Nrf2) and its negative regulator Kelch-like ECH-associated protein 1 (Keap1) comprise a defense mechanism against oxidative stress damage, and growing evidence considers this signaling pathway as a key pharmacological target for the treatment of liver diseases. In this review, we provide detailed and updated evidence regarding Nrf2 and its involvement in the development of the main liver diseases such as alcoholic liver damage, viral hepatitis, steatosis, steatohepatitis, cholestatic damage, and liver cancer. The molecular and cellular mechanisms of Nrf2 cellular signaling are elaborated, along with key and relevant antioxidant drugs, and mechanisms on how Keap1/Nrf2 modulation can positively affect the therapeutic response are described. Finally, exciting recent findings about epigenetic modifications and their link with regulation of Keap1/Nrf2 signaling are outlined.
Solid tumors, beyond mere accumulation of cancer cells, form a complex ecosystem consisting of normal epithelial cells, fibroblasts, blood and lymphatic vessels, structural components, and ...infiltrating hematopoietic cells including myeloid and lymphoid elements that impact tumor growth, tumor spreading, and clinical outcome. The composition of the immune microenvironment is diverse, including various populations of T cells, B cells, dendritic cells, natural killer cells, myeloid-derived suppressor cells, neutrophils, or macrophages. The immune contexture describes the density, location, and organization of these immune cells within solid tumors. In lung cancer, which is the deadliest type of cancer, and particularly in non-small cell lung cancer, its most prevalent form, reports have described some of the interactions between the tumor and the host. These data, in addition to articles on various types of tumors, provide a greater understanding of the tumor-host microenvironment interaction and stimulate the development of prognostic and predictive biomarkers, the identification of novel target antigens for therapeutic intervention, and the implementation of tools for long-term management of patients with cancer.
Nanotechnology enables the development of a new generation of devices at the scale of a few cubic micrometers that can sense, process, and communicate. Such small, imperceptible devices will ...revolutionize healthcare applications and enable new possibilities for in-body environments. This paper studies the intra-body communication channel between nanosensors flowing in the bloodstream and gateways attached to the skin using the terahertz (THz) spectrum. The channel model considers three layers through which the waveform travels: skin, tissue, and blood. To optimize the communication performance, this work investigates the impact of noise and mobility, and subsequently derives the trade-off between them. We illustrate the achievable bit error rate (BER) for THz intra-body channels considering communication through human tissue layers, including noise and random mobility of nanosensors in the blood system.
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