Medical image segmentation using customized U-Net with adaptive activation functions

Neural Computing and Applications - Since medical imaging is a fundamental step in clinical diagnosis and treatment, medical image processing is an attractive field for researchers. Among the...     

Feedback stabilization of discrete-time quantum systems subject to non-demolition measurements with imperfections and delays

We consider a controlled quantum system whose finite dimensional state is governed by a discrete-time nonlinear Markov process. In open-loop, the measurements are assumed to be quantum non-demolition (QND). The eigenstates of the measured observable are thus the open-loop stationary states: they are used to construct a closed-loop supermartingale playing the role of a strict control Lyapunov function. The parameters of this supermartingale are calculated by inverting a Metzler matrix that characterizes the impact of the control input on the Kraus operators defining the Markov process. The resulting state feedback scheme, taking into account a known constant delay, provides the almost sure convergence to the target state. This convergence is ensured even in the case where the filter equation results from imperfect measurements corrupted by random errors with conditional probabilities given as a left stochastic matrix. Closed-loop simulations corroborated by experimental data illustrate the interest of such nonlinear feedback scheme for the photon box, a cavity quantum electrodynamics system.     

Desulfurization of high sulfur petroleum coke by molten caustic leaching

Desulfurization by molten caustic leaching (MCL) at 400–500 °C has been investigated in order to reduce the sulfur content of petroleum coke. Effective parameters on desulfurization of petroleum coke, other than temperature, include alkali to feed (petroleum coke) mass ratio, time and mesh size in the ranges of 0.5–1.5, 1–3 h and 200–600 µm, respectively. In this work, petroleum coke desulfurization conditions using solid KOH have been studied. Maximum petroleum coke desulfurization by MCL method has been obtained by Taguchi L9 design using alkali to feed mass ratio of 1, temperature of 600 °C, time of 2 h and mesh size of 200 µm. The changes in the main groups on the coke surface have been determined using FTIR spectroscopy. In addition, SEM-EDX, TGA and XRD analyses have been used to investigate the changes in coke physical and chemical properties.     

Hybrid II-VI and III-V Compound Double Heterostructures and Their Properties

In this report, n-GaN/n-ZnO/p-GaN double heterostructures (DHs) were grown on sapphire substrate employing metal-organic chemical vapor deposition (MOCVD) and molecular-beam epitaxy (MBE) methods. Scanning electron microscopy (SEM) employed in both secondary electron (SE) and cathodoluminescence (CL) modes revealed high crystal and optical quality of the DH layers, indicating no significant interdiffusion of constituent elements during growth. The diode structures were fabricated whose current-voltage characteristics revealed rectifying behavior with a leakage current 2.12 × 10⁻⁵ A and a forward current 7.8 × 10⁻² A at 10 V bias, and with threshold and breakdown voltages of 3.2 and –11 V, respectively. Under forward bias, an intense electroluminescence (EL) was observed, the spectrum of which depended on the injection current.     

Two-dimensional materials for bone-tissue engineering

There are diverse diseases such as some infections, trauma, and tumor resections during cancer surgery that can cause bone damage or skeletal defects in persons. Most of the time, these defects cannot heal spontaneously due to several medical conditions that patients encounter, like diabetes, hormone-related problems, and autoimmune disorders. This issue is even worse for older people and some special treatments should be provided for them. Bone-tissue engineering has emerged to tackle these challenges. By investigating bone repair strategies, studying bone structures and biomechanics, and employing appropriate growth factors, suitable scaffolds, and biomaterial-centered regenerative approaches can be employed to treat bone defects more effectively. This study reviews some recent bone-tissue-engineering strategies relying on two-dimensional (2D) materials, including graphene and its derivatives, black phosphorus, and MXenes that are exhibiting a great potential in regenerative medicine.     

Structural optimization of four designed roof modules: Inspired by Voronax grid shell structures

Architects have been following nature in their constructions for a long time. Observations of nature reveal that it has many highly developed structures that provide scientists and engineers with a lot of useful clues for creating more efficient structures and building forms. Therefore, revealing systematic thinking about natural species is a crucial requirement for today’s buildings. A software analysis method was used to design four modules in the roof structure of the Iranian University of Science and Technology’s exhibition. The roof structure is based on the Voronax structure, which is a relaxed formof Voronoi, which is seen in the structures ofmany natural creatures. They were analyzed in terms of optimization and structural simulation using Grass-hopper plugins and tools by taking into account VonMises stress in the structural design. The results indicated that by increasing the density of Voronax cells in the areaswith high Von Mises stress concentration, a more efficient structure could be achieved in terms of load-bearing and designing predefined free-form roof structures. By analyzing predefined roof structures in an optimum way, the study took a step toward optimizing these kinds of structures.     

Biopolymer Nanovehicles for Oral Delivery of Natural Anticancer Agents

Cancer is the second leading cause of death throughout the world. Nature-inspired anticancer agents (NAAs) that are a gift of nature to humanity have been extensively utilized in the alleviation/prevention of the disease due to their numerous pharmacological activities. While the oral route is an ideal and common way of drug administration, the application of NAAs through the oral pathway has been extremely limited owing to their inherent features, e.g., poor solubility, gastrointestinal (GI) instability, and low bioavailability. With the development of nano-driven encapsulation strategies, polymeric vehicles, especially those with natural origins, have demonstrated a potent platform, which can professionally shield versatile NAAs against GI barricades and safely deliver them to the site of action. In this review, the predicament of orally delivering NAAs and the encapsulation strategy solutions based on biopolymer matrices are summarized. Proof-of-concept in vitro/in vivo results are also discussed for oral delivery of these agents by various biopolymer vehicles, which can be found so far from the literature. Last but not the least, the challenges and new opportunities in the field are highlighted.