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Imatinib mesylate (IMA) belonging to the selective tyrosine kinase inhibitor family has been proven to induce cardiotoxic effects along with therapeutic strategies. Nrf2-dependent ferroptosis has been implicated in the cardiotoxicity induced by IMA. The present study was designed to investigate the protective effects of berberine hydrochloride (Ber) on cardiac injuries induced by IMA and to explore its potential mechanisms. In H9c2 cells, cell viability, the generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and labile iron pool (LIP) levels were measured. In a mouse model of IMA-induced cardiomyopathy, serum biomarkers and cardiac tissues were examined. A western blot assay was performed to evaluate the expression of ferroptosis-related proteins

Virtual reality education App is the product of the application of virtual reality technology in education, it is a new paradigm of educational technology in the digital age. In this study, Kano model was used to assess the learners' needs for specific design elements in the virtual reality education App from the perspective of user needs. Through the survey method verification, the learner has the high expectation to 7 attributes, carries on the optimization design to these aspects to have the good effect. According to the results, the concrete design scheme of virtual reality education App is summarized in order to guide the development of virtual reality education App in the future.

Background: Three-dimensional facial soft tissue landmark prediction is an important tool in dentistry, for which several methods have been developed in recent years, including a deep learning algorithm which relies on converting 3D models into 2D maps, which results in the loss of information and precision. Methods: This study proposes a neural network architecture capable of directly predicting landmarks from a 3D facial soft tissue model. Firstly, the range of each organ is obtained by an object detection network. Secondly, the prediction networks obtain landmarks from the 3D models of different organs. Results: The mean error of this method in local experiments is 2.62±2.39, which is lower than that in other machine learning algorithms or geometric information algorithms. Additionally, over 72% of the mean error of test data falls within ±2.5 mm, and 100% falls within 3 mm. Moreover, this method can predict 32 landmarks, which is higher than any other machine learning-based algorithm. Conclusions: According to the results, the proposed method can precisely predict a large number of 3D facial soft tissue landmarks, which gives the feasibility of directly using 3D models for prediction.

Colour is an important guideline for selection and consumption. It also draws attention to the designers, as some modern design styles require them to illustrate the taste of the product with a limited number of colours. In this case, a precise description of the taste-colour association is required. The present study explored the colour-taste crossmodal association of two tastes, crisp and dry, which are normally found in beers and are the preferred flavours of Chinese consumers. Experiments were carried out to determine the characteristics of the colours associated with the two tastes. And the strength of the tastes perceived from the colours with different hue angles was investigated. The results of this study reveal that the hue and chroma can both affect the perception of these tastes. Both tastes can be perceived from the same colour, but the strength of the taste can be varied from different hues.

The clinical use of 5-fluorouracil (5-FU), a potent antitumor agent, was limited by severe cardiotoxic effects. The present study was aimed to investigate the protective effects of resveratrol (Res) on 5-FU-induced cardiotoxicity and to explore its potential mechanisms.The cardiotoxicity model was intraperitoneal injection of 5-FU at the dose of 30 mg/kg for 7 consecutive days. Plasma enzymes activities, cardiac tissues were assessed after treatment with Res for 3 weeks. Ferrostatin-1 (Fer-1) was used as ferroptosis inhibitor. In H9c2 cardiomyocyte cells, cell viability, generation of reactive oxygen species (ROS), mitochondrial activity and cellular Fe

The percentage of glycated hemoglobin (HbA1c) in total hemoglobin (Hb) is an important index for the diagnosis of Type II diabetes (T2D) because it reflects the long-term glucose level in blood. Herein, employing a one-pot co-reduction approach using glutathione (GSH) as structure-directing agent, a cluster-like AuAg nanoparticle (AuAg NPs) material was synthesized, therefore an electrochemiluminescence (ECL) aptamer-sensor for HbA1c detection was developed based on functionalized electrode with this material. Meanwhile, the quantitative determination of total Hb was realized based on the quenching effect of Hb on the fluorescence (FL) of luminol. Under compatible conditions, the results of both indexes can be satisfactorily acquired. This multimodal detection system has a good linear response toward Hb from 0.1 to 2.5 μM and HbA1c from 0.005 to 0.5 μM. The blood test proves this strategy is capable of accurate Hb and HbA1c detection, thus to obtain the percentage of HbA1c in total Hb (HbA1c%), which has the potential application for clinical diagnosis of diabetes mellitus.

The use of non-thermal plasma at atmospheric pressure has emerged as a technique for the substrate-free, gas-phase synthesis of graphene nanoflakes (GNFs). In this paper, a non-thermal plasma based...

Objectives Resveratrol (Res) was a naturally occurring polyphenol compound. It has various beneficial effects, including anti-inflammatory, anti-oxidant and anti-cancer effects. However, the anti-cancer activity was hindered by its low targeting and drug release performance. Thus, we synthesized transferrin-cathepsin B cleavable peptide modified mesoporous silica nanoparticle encapsulated Res (Tf-Res-MSN). Methods Res was encapsulated in mesoporous silica nanoparticles (MSN), which was a kind of drug carrier complex. Tf was modified to recognize the cancer cells. Cathepsin B cleavable peptide (Pep) was used to combine Res-MSN complex and Tf to construct the final product. Pep was used as linker and trigger for Res release. Key findings The smart nanocarriers were increased the drug release performance of Res in human breast cancer (MCF-7) cells. The physicochemical properties of Tf-Res-MSN were assessed by zeta potential, UV-Prove, diffraction scanning calorimetry (DSC), nitrogen physisorption analysis and transmission electron microscope (TEM). MTT assay, AO and Annexin V-FITC/PI staining were performed to explore the anti-tumour activity of Tf-Res-MSN. The results showed that Tf-Res-MSN significantly decreased cell viability and increased cell apoptosis. The inhibition rate and apoptotic rate of Tf-Res-MSN in MCF-7 cells were 95.75% and 80.8%, respectively. Conclusion Our study demonstrated that Tf-Res-MSN was a valuable technique with potential value in breast cancer applications.

The major problems with cancer therapy are drug-induced side effects. There is an urgent need for safe anti-tumor drugs. Artemisinin is a Chinese herbal remedy for malaria with efficacy and safety. However, several studies reported that artemisinin causes neurotoxicity and cardiotoxicity in animal models. Recently, nanostructured drug delivery systems have been designed to improve therapeutic efficacy and reduce toxicity. Artemisinin has been reported to show anticancer properties. The anticancer effects of artemisinin appear to be mediated by inducing cell cycle arrest, promoting ferroptosis and autophagy, inhibiting cell metastasis. Therefore, the review is to concentrate on mechanisms and molecular targets of artemisinin as anti-tumor agents. We believe these will be important topics in realizing the potential of artemisinin and its derivatives as potent anticancer agents.

A novel approach for the preparation of few-layer graphene nano-flakes (GNFs) is presented in this paper. The GNFs are continuously synthesized by thermal decomposition of hydrocarbons using a magnetically rotating arc at atmospheric pressure. The effects of magnetic field, arc current, feedstock gas flow rate, and feedstock gas type on the morphologies and microstructures of pyrolysis products are investigated and discussed. Results show that the microscopic characteristics of pyrolysis products are affected by the operating parameters. High temperature and high hydrogen concentration are considered the essential condition for the formation of GNFs. The synthesized GNFs are agglomerative flakes, where each flake is between 50 and 300 nm. Material analyses indicates that the GNFs have excellent properties such as a good crystalline structure, a low number of layers, and a large specific surface area. This indicates that the GNFs could be applied in fuel cells and energy storages. This method is suitable for mass production of few-layer GNFs since it is a continuous process with a relatively high yield (∼14%) and a relatively low energy cost (∼0.4 kWh/g).

Imatinib Mesylate (IMA) has been widely used to treat with chronic myeloid leukemia (CML). However, cardiotoxicity associated with IMA is included among the therapeutic strategies. The present study was aimed to discover whether ferroptosis, a programmed iron-dependent cell death, is involved in IMA-induced cardiotoxicity. In vivo, mouse model was established after treated with 25 mg/kg, 50 mg/kg and 100 mg/kg IMA. Serum CK, LDH, AST activities were determined. Cardiac tissues were examined by HE and Oil Red O staining. MDA was measured to assess production of lipid peroxide. Tissue iron and GSH content were measured. In vitro, cell viability, mitochondria membrane potential, generation of reactive oxygen species (ROS) and cellular iron levels were performed to explore the mechanism of IMA. The in vivo results revealed that IMA treatment significantly increased serum CK, LDH and AST. HE staining showed that IMA caused cardiac structural injuries. The dose-dependent decrease of GSH and increase of tissue iron and MDA were observed in IMA-treated groups. Oil Red O staining suggested obvious cardiac lipid accumulation after treated with IMA. In H9c2 cardiomyocytes, IMA significantly inhibited cell proliferation in a dose-dependent manner. Mitochondria membrane potential assay showed that IMA destroyed the mitochondrial function. Additionally, IMA increased the cellular ROS and iron levels. Furthermore, IMA down-regulated the expression of Nrf2 and up-regulated the expression of P53 and TfR. These results provided compelling evidence that ferroptosis participates in IMA-induced cardiotoxicity. Ferroptosis could be regarded as a target to protect against cardiotoxicity in IMA-exposed patients.

Cardiac fibrosis is a major contributor for diabetic cardiomyopathy and Dendrobium officinale possessed therapeutic effects on hyperglycemia and diabetic cardiomyopathy. To further investigate the possible mechanisms of the Dendrobium officinale on diabetic myocardial fibrosis in mice. Water-soluble extracts of Dendrobium officinale (DOE) from dry stem was analyzed by HPLC and phenol-sulfuric acid method. Diabetic mice were induced by intraperitoneal injection of streptozotocin (STZ) (30 mg/kg) for 4 consecutive days after intragastric administration of a high-fat diet (HFD) for 2 weeks. The groups were as follows: control group, model group, DOE low, medium, high dose group (75, 150, 300 mg/kg) and Metformin positive group (125 mg/kg). The results showed that DOE dose-dependently lower serum insulin, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and grew the high-density lipoprotein cholesterol (HDL-C) after 12 weeks of daily administration with DOE. Hematoxylin-eosin staining and Sirius red staining showed obvious amelioration of cardiac injury and fibrosis. In addition, the result of immunoblot indicated that DOE increased the expression of peroxisome proliferator activated receptor-α (PPAR-α), phosphorylation of insulin receptor substrate 1 (p-IRS1) and E-cadherin and repressed the expression of transforming growth factor β1 (TGF-β1), phosphorylation of c-Jun N-terminal kinase (p-JNK), Twist, Snail1 and Vimentin. The present findings suggested that DOE ameliorated HFD/STZ-induced diabetic cardiomyopathy (DCM). The possible mechanism mainly associated with DOE accelerating lipid transport, inhibiting insulin resistant and suppressing fibrosis induced by epithelial mesenchymal transition (EMT).

In this study, a cylindrical plasma generator with an axial magnetic field is constructed to obtain the magnetically stabilized gliding arc discharge (MSGAD). Using high speed photography, voltage waveform analysis and spectral diagnostics, the MSGAD physical characteristics, such as arc voltage, rotation speed, electric field, excitation/rotational temperature, etc., are investigated under different magnetic field. The experimental results reveal that as the magnetic field increases, the arc voltage, rotation speed, electric field and non-equilibrium level increase, and the MSGAD is more stable under the larger magnetic field. Additionally, carbon black nanoparticles with “crumpled paper sheet” structure are prepared by the MSGAD. The results indicate that the enhanced magnetic field can promote the transition from amorphous carbon to crystalline graphite. It is inferred that the transition is likely relevant to the rotation speed and electron energy of the arc plasma.

Potassium ion batteries (PIBs) have drawn considerable attention owing to the low cost and high natural abundance of potassium. However, risks associated with the extremely high activity of potassium metal have motivated the search for alternative anode materials with high performance and good safety. Herein, an essential element of the human body, vitamin K, is applied as an organic redox-active electrode material for PIBs. This biomolecule has a quinone structure with two active redox carbonyl groups, which can provide a theoretical specific capacity of 313.5 mA h g−1. After hybridization with graphene nanotubes (GNTs), the composite delivered a high reversible capacity of 300 mA h g−1 and maintained 222.3 mA h g−1 after 100 cycles at a current density of 100 mA g−1 with a coulombic efficiency of ∼99%. Moreover, at higher current densities of 200, 500, and 1000 mA g−1, it maintained high discharge capacities of 203, 181, and 165 mA h g−1, respectively. The enhanced electrochemical performance of the composite might be attributed to the improved electronic conductivity and inhibition of vitamin K dissolution into the organic electrolyte. This biomolecule-based electrode offers a new alternative approach to the development of PIBs.

A cluster-like AuAg alloy hollow-nanoparticles (HNPs), synthesized by facile one-pot co-reduction under the guidance of bovine serum albumin (BSA), enhanced the electrochemiluminescence (ECL) of luminol, thus to be served as the sensing matrix of the enzymatic glucose biosensor. The prepared HNPs were characterized by electronic microscopy, UV–Vis spectrometry, IR spectrometry, X-ray diffraction analysis, X-ray photoelectron spectroscopy and electrochemistry. Using hydrolyzed APTMS to connect AuAg HNPs on indium tin oxide (ITO) coated glass, the synergistic effect between two metals makes it had 20 multiple enhancement of ECL, and shows sensitive response toward reactive oxygen species. After loading GOD on this matrix to build the glucose sensor, it has a wide linear response range for the glucose from 5.0 μM to 1.0 mM with a detection limit as 0.40 μM. It can be applied for noninvasive detection of glucose with saliva as specimen, the results indicated the high-degree correlation of glucose contents between saliva and blood.

A non-thermal plasma source based on magnetically stabilized gliding arc discharge (MSGAD) was used to prepare carbon nanoparticles via methane decomposition. Spherical carbon nanoparticles (SCNs), few-layer graphene nanoflakes (GNFs), and nitrogen-doped carbon nanoparticles were obtained. The results showed that the product microstructure was influenced by the buffer gas. In pure methane and argon, the products were a mixture of SCNs and GNFs. In helium and hydrogen, all products were highly crystalline GNFs with low defects, few layers, large BET surface areas, and excellent thermal stability. Under a nitrogen atmosphere, nitrogen-doped nanoparticles were formed, and the products were a mixture of GNFs, disordered graphitic layers, and tiny spots similar to carbon dots. The formation of GNFs was possibly related to the high input power and abundant hydrogen atoms, while the complex product morphology obtained under a nitrogen atmosphere was likely caused by the incorporation of nitrogen atoms.

Few-layer graphene nano-flakes (GNFs) are successfully prepared via hydrocarbon pyrolysis using a non-thermal plasma process based on a magnetically stabilized gliding arc discharge (MSGAD) at atmospheric pressure. The effects of feedstock gas type and hydrogen flow rate on the morphology of carbon nanomaterials are investigated. When the hydrogen/carbon (H/C) molar ratio is 4, the synthesized GNFs consist of 10 layers per stack with dimensions between 100 and 300 nm in a 4.57.2% yield. The energy cost is 0.1–0.2 kWh/g, which makes this process feasible for large-scale GNFs production. The results show that appropriately increasing the H/C molar ratio promotes the morphological transformation of carbon nanomaterials from spherical carbon nanoparticles (SCNs) to GNFs, improve the quality of GNFs and reduce the stacking of graphite layers. However, increasing the H/C ratio reduces the yields of carbon nanomaterials, so as to increase the energy cost. Analysis suggests that increasing the H/C ratio reduces the concentration of polycyclic aromatic hydrocarbon (PAH) and generates more H atoms, which helps form a two-dimensional nucleation and promotes planar growth. However, an excessive H/C ratio may introduce some defects due to an etching effect.

A novel non-thermal plasma process based on magnetically stabilized gliding arc discharge (MSGAD) is developed for continuous synthesis of carbon nano-onions (CNOs). CNOs with a diameter range of 70–200 nm are continuously prepared by propane decomposition. Results indicate that with increased residence time in the plasma region, the product morphology gradually changes from graphene nanoflakes (GNFs) to CNOs. It is proposed that CNOs synthesis mainly includes three stages: formation of GNFs, curving and closure of multiple GNFs, further graphitization. In addition, H2 content has a key role in CNOs formation since hydrogen has a significant effect on the formation and morphology of GNFs.

A thermal plasma process at atmospheric pressure is an attractive method for continuous synthesis of graphene flakes. In this paper, a magnetically rotating arc plasma system is employed to investigate the effects of buffer gases on graphene flakes synthesis in a thermal plasma process. Carbon nanomaterials are prepared in Ar, He, Ar-H2, and Ar-N2 via propane decomposition, and the product characterization is performed by transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and the Brunauer&ndash, Emmett&ndash, Teller (BET) method. Results show that spherical particles, semi-graphitic particles, and graphene flakes coexist in products under an Ar atmosphere. Under an He atmosphere, all products are graphene flakes. Graphene flakes with fewer layers, higher crystallinity, and a larger BET surface area are prepared in Ar-H2 and Ar-N2. Preliminary analysis reveals that a high-energy environment and abundant H atoms can suppress the formation of curved or closed structures, which leads to the production of graphene flakes with high crystallinity. Furthermore, nitrogen-doped graphene flakes with 1&ndash, 4 layers are successfully synthesized with the addition of N2, which indicates the thermal plasma process also has great potential for the synthesis of nitrogen-doped graphene flakes due to its continuous manner, cheap raw materials, and adjustable nitrogen-doped content.

It has been documented that diseases can spread within an aircraft cabin from the sneezing, coughing or breathing of a sick passenger. To understand the spreading mechanism it is very important to quantify the airflow and droplet transmission around a sneezing/coughing incident. In this project, tracer gas experiments were carried out in a full-scale Boeing 767-300 mock-up to study the global transport process of contaminated air within the cabin. Computational fluid dynamics (CFD) simulation was also used to provide additional information for understanding the principle. A steady airflow field was simulated first and then it was compared with the experimental data. The global airflow patterns were similar to those observed experimentally. This velocity field was adopted as the initial condition for further unsteady pollutant transport simulation. Experimental and simulated results were compared and discussed to develop a relationship between concentration and airflow pattern, source location, transport direction, and ventilation rate. Finally, the overall picture of concentration evolution by both experimental and simulated approaches was discussed.

The evaluation of temperature data recorded on the world's longest bridge built over ice-covered water is presented. The data in question are the hourly recorded temperatures in three girder sections with variable geometry and ambient temperature, solar radiation, and wind speed measured on site from 1998 to 2000. The data were first carefully screened, and problematic records were identified and repaired. The temperatures were then spatially reduced to a set of thermal variables including average, differential, and residual temperatures. Extreme value analysis was performed to obtain 100 year return thermal loads. The results are compared with the provisions in the Canadian highway bridge design code (CAN/CSA-S6-00) and the original design temperatures for the bridge. Temperature distributions for maximum positive vertical differential temperatures during the recording period are plotted for the three girder sections. The observed unrestrained curvatures and nonlinear stresses are compared with those estimated by the Priestley model. Modifications are found to be necessary for extremely deep cross sections.Key words: concrete bridge, thermal response, statistical evaluation, average temperature, differential temperature, curvature, stress.

In complex ventilation systems with air recirculation, the contaminant concentration at the supply inlets is generally unknown, which limits the application of computational fluid dynamics (CFD) tools to simulate the indoor contaminant distribution. In this article, we develop a new algorithm that can deal with different ventilation scenarios while it requires minimum computing time. This algorithm divides indoor contaminant distribution into two parts: the contribution from inlets and the contribution from sources. The former can be obtained with the concentrations at inlets and volume fraction for each inlet, which is defined as the relative concentration when the boundary concentrations are 1 for the inlet and 0 for other inlets. The latter is calculated by setting the concentrations at all inlets as 0. By combining the contaminant transportation characteristics in rooms and system ducts, the algorithm does not require iteration to solve the contaminant distribution in actual ventilation systems. The d...

Air age is an important index to evaluate indoor air quality in ventilated rooms. Current definition of air age is limited to indoor part, i.e., the air age at the inlets of air supply diffusers is assumed to be zero. This work extends the air age concept to the so-called “total air age” by considering the impact of air delivery process on air age. The air age in duct is solved using one-dimensional flow characteristic, which includes the mixing process between airflows with different ages. It is then coupled with the room air age which is solved using computational fluid dynamics technique. An iterative algorithm is proposed to calculate total air age in general ventilation systems and a direct method is further derived for systems with only one air handling unit. Two examples are given to demonstrate the calculation of total air age and the distributions of total air age are compared with those of traditional air age.

Air-exchange efficiency is widely used to indicate the ventilation effect and indoor air quality in ventilated rooms. However, it does not take occupant distribution in the room into account and is thus limited. In this paper, a revised air-exchange efficiency (occupant air-exchange efficiency) that differentiates between different zones by considering different occupancy in each zone is developed. Results from studies of a large-space ventilation case, a personalized ventilation case, and a displacement ventilation case show that occupant air-exchange efficiency can better be used to evaluate the ventilation effect of a room.

Fresh air age is an important index to evaluate indoor environment. The conventional method for measuring or calculating fresh air age is only suitable for simple ventilation systems and not for central ventilation systems. In this paper, an algorithm for calculating fresh air age in central ventilation system is presented, which is based on the analysis of air flow in duct and air mixing. An example is given to illustrate the algorithm. The fresh air age in every ventilated room and duct can be acquired after all rooms and duct are directly calculated in turn without iteration. The algorithm is suitable for different central ventilation systems.

This paper presents a polynomial-time algorithm for designing digital filters with coefficients expressible as sums of signed power-of-two (SPT) terms. Our proposal is based on an observation that under certain circumstances, the realization cost of a filter with SPT coefficients depends only on the total number of SPT terms, regardless of how the terms distribute among the coefficients. Therefore, the number of SPT terms for each coefficient is not necessarily limited to a fixed number. Instead, they should be allowed to vary subject to a given number of total SPT terms for the filter. This provides the possibility of finding a better set of coefficients. Our algorithm starts with initializing all the quantized coefficient values to zero. It chooses one SPT term at a time and allocates it to the currently most deserving coefficient to minimize the L/sup /spl infin// distance between the SPT coefficients and their corresponding infinite wordlength values. This process of allocating the SPT terms is repeated until the total number of SPT terms for the filter is equal to a prescribed number. For each filter gain, the time complexity is a second-order polynomial in the number of coefficients to be optimized and is a first-order polynomial in the filter wordlength.

It is well known that if each coefficient value of a digital filter is a sum of signed power-of-two (SPT) terms, the filter can be implemented without using multipliers. In the past decade, several methods have been developed for the design of filters whose coefficient values are sums of SPT terms. Most of these methods are for the design of filters where all the coefficient values have the same number of SPT terms. It has also been demonstrated recently that significant advantage can be achieved if the coefficient values are allocated with different number of SPT terms while keeping the total number of SPT terms for the filter fixed. In this paper, we present a new method for allocating the number of SPT terms to each coefficient value. In our method, the number of SPT terms allocated to a coefficient is determined by the statistical quantization step-size of that coefficient and the sensitivity of the frequency response of the filter to that coefficient. After the assignment of the SPT terms, an integer-programming algorithm is used to optimize the coefficient values. Our technique yields excellent results but does not guarantee optimum assignment of SPT terms. Nevertheless, for any particular assignment of SPT terms, the result obtained is optimum with respect to that assignment.

This paper presents a method to find the minimum number of adders for implementing a multiplier of a given multiplicand and the corresponding structure to realize it. In comparison with the widely used structure based on the canonic signed digit (CSD) expression of multiplicands, the number of adders required by using our structure is not more than that of the CSD structure for any multiplicand. The contiguous range of integer multiplicands whose corresponding multiplications can be implemented by no more than a given number of adders increases exponentially with the increase of the number of adders allowed. It is shown that the ratio of the largest contiguous integer range of our structure to that of the CSD structure is equal to 10.76 and 64.43, respectively, for using no more than 4 and 5 adders. Our method for replacing multipliers with shifters and adders is applied to the design of multiplierless digital filters. Experimental results show that the normalized peak ripples of the filters designed by our method is decreased by up to 4.2 dB over those obtained by the corresponding design method based on the CSD expression of filter coefficients. >

A decoupled full-dimension form is introduced for state models. In this form, the dimension of the state vector is time-invariant, which is equal to the dimension of the state-space at each time instant. Therefore, the dimension of the state vector is minimized from the time-variant point of view and all the state variables are independent. Moreover, the state vector in a state model of the decoupled full-dimension form is partitioned into two decoupled subvectors, each of which alone forms a subsystem. One of the subsystems is an FIR system whose state vector is dependent only on inputs at (finitely) past instants. In addition, this subsystem is completely reachable. The other subsystem is an IIR system whose state-space is equal to the force-free solution set of the state vector of the subsystem. It is proved that every state model in the conventional form can be mapped by a linear one-to-one map into an equivalent state model in the decoupled full-dimension form. In comparison with a state model in the...

This paper presents a method for synthesizing a recursive linear time-variant digital filter in finite time domain. The desired filter can be nonrecursive and is given by its generalized frequency function. The synthesized filter is described by a linear difference equation with time-variant coefficients. These coefficients at a given time instant are derived recursively from those at the previous instants. In addition, for the determined coefficients at the previous instants, the coefficients at the given instant minimize the error between the generalized frequency function of the desired filter and that of the synthesized one at the given instant. The performance of this method is illustrated and compared with another available method through numerical examples. The results show an improvement of nearly two order of magnitude in the normalized mean squared error between the amplitudes of the generalized frequency function of the desired filter and that of the synthesized.

This paper addresses the problem of optimal administration of chemotherapeutic agents for the treatment of brain tumors by convection-enhanced drug delivery. The optimal catheter position is located by a novel optimization technique, which simultaneously maximizes drug concentration in the desired brain region, while ensuring that the final drug concentration does not fall below a therapeutically effective level or rise above the toxic threshold in non-treatment areas. A modified finite volume discretization method is used inside a nonlinear hybrid optimization algorithm. The distributed optimization problem with an embedded transport problem is solved on a coarse computational mesh, while searching for the optimal catheter position in a separate continuous coordinate system. In order to obtain continuous positional dependency of the objective function, two reference systems are used for solving the transport equations. The first analytical method projects the outflow from a specific catheter position inside the coarse finite volume cell onto its vertices. Once the cell face flux resulting from a specific continuous catheter positions are thus determined, the remaining two-dimensional transport problem is solved rigorously with a classical finite element method. A score function φ evaluates the match between the drug distributions achieved by a particular catheter placement with the therapy goals. Genetic inheritance adjusts the catheter locations to identify the globally optimal solution. Using the novel multi-scale algorithm, it is possible to optimize catheter placement and design, as well as to control drug distribution volume without the need for mesh refinement for different catheter positions.

In this paper the rejection of a narrow-band interference in DS (direct-sequence) spread spectrum communication systems by a digital filter is explored. A method for estimating the dominant frequency of the interference is presented. According to the estimated frequency the filter coefficients of a bandpass error filter are generated such that its centre frequency is at the estimated one. This error filter is realized by a recursive structure with only six multiplications and is approximately of zero phase. The interference is suppressed by compensating the non-filtered signal with the filtered one. A method to extract the characteristics of the different type of interferences is also presented in order to adjust the filter to make it suitable for their rejection. The performances of the filter in the environment of a white Gaussian noise and a narrow-band interference such as single-tone, swept-tone and narrow-band Gaussian interferences are simulated by computer, which shows that by using the given filter, the system performance can be greatly improved.

An algorithm is presented for designing digital filters with coefficients expressible as sums of signed power-of-two (SPT) terms. For each filter gain, the time complexity of the algorithm is a second-order polynomial in the filter order and is a first-order polynomial in the filter wordlength. Unlike conventional methods where each coefficient is allocated a fixed number of SPT terms, the author's method allows the number of SPT terms for each coefficient to vary subject to the number of SPT terms for the entire filter. This provides the possibility of finding a better filter without increasing the number of adders, which determines the realization cost for a given filter length. Application of the algorithm to finite impulse response (FIR) filter designs shows that it achieves up to 8.9 dB improvement over simulated annealing and mixed integer linear programing on the normalized peak ripples of example filters. >

A linear time-variant (LTV) digital filter having a separable sequence as its impulse response has been proved to be recursive. Such filters have the potential of saving computation time and storage. Two techniques are presented for synthesizing a desired LTV digital filter given in numerical form in a finite time domain by a separable sequence. The first is a realization technique which decomposes the impulse response of a desired filter into a separable sequence and theoretically leads to the solution of a separable sequence with the lowest order. For a numerical solution, the order of the separable sequence is dependent on an error tolerance that reflects the realization accuracy. If the desired filter is recursive, then the exact order can be solved. The solved order, as well as the decomposition error, is independent of the error tolerance in a wide range. The second is an approximation technique which finds a separable sequence of a given order by minimizing the normalized mean squared error between the impulse response of the desired filter and the separable sequence. The technique searches the separable sequence by alternately using two nonlinear restrictions that an optimally approximated filter must satisfy. The performances of the proposed techniques are illustrated and compared with other available techniques through numerical examples. The results of the comparisons show that our approximation technique results in smaller approximation errors than those of the others. >

It is well known that if each coefficient value of a digital filter is a sum of SPT terms, the filter can be implemented without using multipliers. In the past decade, several methods had been developed for the design of filters whose coefficient values are sums of SPT terms. Most of these methods are for the design of filters where all the coefficient values have the same number of SPT terms. In this paper, we present a new method for allocating different number of SPT terms to each coefficient value keeping the total number of SPT terms fixed. Our technique yields excellent results.

The paper presents a computationally efficient realization technique for recursive linear time-variant (LTV) digital bandpass filters by transforming lowpass ones. The transformation is based on the principle that an input signal is first demodulated, then filtered by lowpass filters, and at last modulated back again. The presented technique simples this procedure and needs no modulators and demodulators. The performance of this transformation is illustrated

The performance of a particle tracking algorithm which detects particle trajectories from discretely recorded particle positions could be substantially hindered by the input noise. In this paper, a particle tracking algorithm is developed which is robust against input noise. This algorithm employs the regression method instead of the extrapolation method usually employed by existing algorithms to predict future particle positions. If a trajectory cannot be linked to a particle at a frame, the algorithm can still proceed by trying to find a candidate at the next frame. The connectivity of tracked trajectories is inspected to remove the false ones. The algorithm is validated with synthetic data. The result shows that the algorithm is superior to traditional algorithms in the aspect of tracking long trajectories.