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Topic Review
Arginine Signaling and Cancer Metabolism
Arginine is an amino acid critically involved in multiple cellular processes including the syntheses of nitric oxide and polyamine, and is a direct activator of mTOR, a nutrient sensing kinase strongly implicated in carcinogenesis. In this review, we will discuss arginine as a signaling metabolite, arginine’s role in cancer metabolism, arginine as an epigenetic regulator, arginine as an immunomodulator, and arginine as a therapeutic target. The different cell killing mechanisms associated with various cancer types will also be described.
  • 26935
  • 29 Mar 2022
Topic Review
Calendar of 13 Months
Has anyone of us missed an event because he was confused between days and dates? Do we really remember the date of any day if we do not have a calendar? Is the current Gregorian Calendar efficient enough for use, and does it really facilitate our life or make it more complicated?  Have you ever thought about a much simpler way to calculate days and dates in a year? All these questions are answered in this article, in which the author proposes an original calendar that might facilitate our lives if we can apply it.
  • 24365
  • 28 Oct 2020
Topic Review
Space Vector PWM Techniques
This entry elaborates the basic concept of space vector Pulse Width modulation technique for a three-phase voltage source inverter. Why space vector Pulse width modulation (PWM) is required and how it is implemented in the simulation model, is described in the entry.  A number of PWM scheme is used to obtain variable voltage and frequency supply from a power converter. The most widely used PWM schemes for three-phase voltage source inverter (VSI) are carrier-based sinusoidal PWM and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realization and better dc bus utilization. This entry focuses on step by step development of MATLAB/SIMULINK model of SVPWM. Firstly the model of a three-phase VSI is discussed based on space vector representation. Next simulation model of SVPWM is obtained using MATLAB/SIMULINK. Simulation results are also provided. 
  • 18101
  • 16 Jun 2022
Topic Review
Ammonia Production
Ammonia is the second-largest global chemical products, utilized as agricultural fertilizer, food production, industrial materials, refrigerants, and additives. Recently, the utilization of ammonia as the energy carrier (secondary energy source) has attracted many interests, due to its high volumetric hydrogen density, low storage pressure, high stability for long-term storage, high auto-ignition temperature, low condensation pressure, and lower gas density than air. in general, ammonia production includes the currently adopted thermochemical (Haber–Bosch), electrochemical, and photochemical cycle processes. 
  • 17620
  • 20 May 2022
Topic Review
Organizational Environment
The organizational environment is the set of forces surrounding an organization. These forces may hamper or facilitate the organization’s access to resources, which means they can both offer opportunities and pose threats. Moreover, while these resources are valuable for the organization, they are also scarce (Riggio, 2018). The forces encompassed by the concept of the organizational environment include, among others, competition between rivals to retain customers, fast-paced changed in technology, and an increase in the price of raw materials. All these factors may somehow erode an organization’s competitive advantage. Consequently, the forces at play in the environment can influence the organization’s behavior (Truxillo, Bauer & Erdogan, 2016). 
  • 15597
  • 02 Feb 2021
Topic Review
Electronic Circular Dichroism
This entry provides an introduction to the basic concepts of Electronic Circular Dichroism (ECD) spectroscopy. It describes the fundamental principles, instrumentation, and different approaches for interpreting and predicting ECD spectra. It surveys the most popular modern applications of ECD for the structural analysis of organic compounds.
  • 11666
  • 24 May 2022
Topic Review
Gompertz Function with R
The Gompertz function is a sigmoid curve being a special case of a logistic curve. Although it was originally designed to describe mortality, it is now used in biology. For example, it is useful to describe many  phenomena such as the growth of a cancerous tumor confined to an organ without metastasis, the growth of the number of individuals in a population, e.g. prey in a Volterra-Lotka model, the germination of seeds, etc. It also models as the logistic function the growth of a colony of bacteria or in an epidemic the spread of the number of infected people. However, despite its many applications, in many cases the fitting of experimental data to the Gompertz function is not always straightforward. In this article we present a protocol that will be useful when performing the data regression to this curve using the statistical package R.
  • 9216
  • 07 Apr 2021
Topic Review
Perceptual Organization
Gestalt theory has provided perceptual science with a conceptual framework relating to brain mechanisms that determine the way we see the visual world. This is referred to as "Perceptual Organization" and has inspired researchers in Psychology, Neuroscience and Computational Design ever since. The major Gestalt principles, such as the principle of Prägnanz, and more importantly the Gestalt laws of perceptual organization, have been critically important to our understanding of visual information processing, how the brain detects order in what we see, and derives likely perceptual representations from statistically significant structural regularities. The perceptual integration of contrast information across co-linear space for the organization of objects in the 2D image plane into figure and ground convey the most elementary basis to our understanding of the visual world. Gestalt theory continues to generate powerful concepts and insights for perceptual science even today, where it is to be placed in the context of image-base decision making by human minds and machines.
  • 8539
  • 22 Mar 2021
Topic Review
Liquid–Liquid Phase Separation
Liquid–liquid phase separation (LLPS) is a thermodynamically-driven, reversible phenomenon consisting in de-mixing into two distinct liquid phases, with different solute concentrations.
  • 7724
  • 24 Feb 2021
Topic Review
Sensors for Health Monitoring
The use of wearable equipment and sensing devices to monitor physical activities, whether for well-being, sports monitoring, or medical rehabilitation, has expanded rapidly due to the evolution of sensing techniques, cheaper integrated circuits, and the development of connectivity technologies. In this scenario, this paper presents a state-of-the-art review of sensors and systems for rehabilitation and health monitoring. Although we know the increasing importance of data processing techniques, our focus was on analyzing the implementation of sensors and biomedical applications. Although many themes overlap, we organized this review based on three groups: Sensors in Healthcare, Home Medical Assistance, and Continuous Health Monitoring; Systems and Sensors in Physical Rehabilitation; and Assistive Systems.
  • 7683
  • 19 Feb 2021
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