3,274 research outputs found

    Novel CCII-based Field Programmable Analog Array and its Application to a Sixth-Order Butterworth LPF

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    In this paper, a field programmable analog array (FPAA) is proposed. The proposed FPAA consists of seven configurable analog blocks (CABs) arranged in a hexagonal lattice such that the CABs are directly connected to each other. This structure improves the overall frequency response of the chip by decreasing the parasitic capacitances in the signal path. The CABS of the FPAA is based on a novel fully differential digitally programmable current conveyor (DPCCII). The programmability of the DPCCII is achieved using digitally controlled three-bit MOS ladder current division network. No extra biasing circuit is required to generate specific analog control voltage signals. The DPCCII has constant standby power consumption, offset voltage, bandwidth and harmonic distortions over all its programming range. A sixth-order Butterworth tunable LPF suitable for WLAN/WiMAX receivers is realized on the proposed FPAA. The filter power consumption is 5.4mW from 1V supply; it’s cutoff frequency is tuned from 5.2 MHz to 16.9 MHz. All the circuits are realized using 90nm CMOS technology from TSMC. All simulations are carried out using Cadence

    A novel DC current transformer using magneto-resistance sensors for FAIR

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    In Silico Investigation of the Binding of MCoTI-II Plant Defense Knottin to the γ-NGF Serine Protease of the 7S Nerve Growth Factor Complex and Biological Activity of Its NGF Mimetic Properties

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    Copyright © 2019 American Chemical Society. Nerve growth factor (NGF) is an endogenously produced polypeptide that promotes the differentiation, survival, and repair of neurons in the central and peripheral nervous systems. While trophic proteins hold promise for the treatment of neuronal injury and disease, use of NGF is limited by its large molecular weight, lack of permeability through the blood-brain barrier, and peripheral side effects. Previously, we found that an extract of the Momordica cochinchinensis seed stimulated PC-12 neurite outgrowth. Bioactivity-guided fractioning of the seed extract suggested that the NGF mimetic agent was one of few defined proteins from this plant: one group being the defense Knottins and the other group of the lowest mass is the potent trypsin inhibitor MCoTI-II. Here, the NGF mimetic potential of this latter protein was investigated using two concurrent but different approaches. A biological study used recombinant purified MCoTI-II, which when tested in rat PC-12 cells grown on collagen, failed to initiate outgrowth relative to the positive control 7S NGF. In a separate computational study, the possibility was investigated such that MCoTI-II could exert an effect through binding to the serine protease γ-NGF subunit of the 7S NGF complex, analogous to its binding to its native receptor trypsin. Molecular dynamics simulations showed that MCoTI-II can bind stably to γ-NGF for >350 ns. Modeling indicated that this interaction could sterically inhibit 7S NGF complex formation, potentially altering the equilibrium between inactive complexed and free active NFG protein. In conclusion, the biological study now excludes the MCoTI-II protein as the NGF mimetic factor in the Momordica extract, an important and required step to identify the active component in this seed. On the other hand, the theoretical study has revealed a novel observation that may be of use in the development of strategies to affect NGF activity

    Significance of serum levels of angiopoietin-2 and its relationship to Doppler ultrasonographic findings in rheumatoid arthritis patients

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    AbstractBackgroundAngiopoietin-2 (Ang-2) is connected to angiogenesis in synovial regions, but the significance of its levels in patients with rheumatoid arthritis (RA) is still unclear.Aim of the workTo evaluate the significance of serum levels of Ang-2 in patients with RA. Also, to determine Ang-2 relationship to the findings of joints Doppler ultrasonographic findings.Patients and methodsThis study included 40 patients with RA, and 25 matched healthy controls. All patients were subjected to assessment of pain using visual analogue scale (VAS), assessment of personal activity using the Health Assessment Questionnaire (HAQ) score, and calculation of disease activity score (DAS 28). Laboratory assays of complete blood count (CBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) titre, and measurement of serum levels of Ang-2 by ELISA. Doppler ultrasonography (US) assessment for eight joints, with calculation of synovial thickness and total signal score (TSS), was done.ResultsSerum Ang-2 levels were significantly higher among patients (3191.3±594.9pg/ml) than controls (1771.7±103.1pg/ml) (p<0.001). Serum Ang-2 levels were significantly correlated with ESR, CRP, DAS28, and duration of morning stiffness (p<0.001, p<0.001, p<0.001, and p=0.025, respectively). There was a significant correlation between serum Ang-2 levels and findings of US, regarding joint synovial thickness, and TSS (p<0.001, for both).ConclusionPatients with RA had significantly higher levels of serum Ang-2 versus controls. In those patients, serum Ang-2 levels were significantly correlated with disease activity markers (ESR, CRP), DAS28, and duration of morning stiffness. Moreover, these levels were significantly correlated with synovial thickness, and TSS. The role of Ang-2 in RA pathogenesis might open the door to the development of new therapeutic strategies, particularly which target angiogenesis

    Sesame seed sensitization in a group of atopic Egyptian children

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    Background: There are no published data on the prevalence of sesame allergy/sensitization in Egypt. Objective: In this pilot study, we thought to estimate the frequency of sesame seed sensitization in a group of atopic Egyptian infants and children. Methods: We consecutively enrolled 90 patients with physician diagnosed allergic disease. The study measurements included clinical evaluation for the site and duration of allergy, history suggestive of sesame seed allergy, and family history of allergy, as well as skin prick testing (SPT) using a commercial sesame extract, and serum sesame specific IgE (SpIgE) estimation. Results: None of the studied patients reported symptoms suggestive of sesame seed allergy. Nevertheless, two children (2.2%) showed positive SPT response to sesame (wheal diameter ≥ 3 mm above the negative control). Only one of them had a wheal diameter which exceeded that of the histamine control. The serum sesame SpIgE exceeded 0.35 IU/ml in all subjects [range = 0.35 - 3.0 IU/ml; median (IQR) = 0.9 (0.6) IU/ml]. Serum sesame SpIgE was significantly increased in patients with history of recurrent urticaria (p=0.03). Conclusion: Sesame seed sensitization is not uncommon in atopic Egyptian children. It can be associated with any clinical form of allergy and the causal relationship needs meticulous evaluation. Wider scale population-based studies are needed to assess the prevalence of sesame allergy and its clinical correlates in our country.Keywords: Food allergy, sesame, atopic children

    Parallel Distributed Compensation-PID Controller Design for Maximum Power Point Tracking of Dynamic Loaded Photovoltaic System

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    Control issues come from the output voltage of PV installations and systems operating in a range of irradiance and temperature. By using a DC converter, such systems are able to maintain a constant output voltage despite fluctuations in the generated voltage and load. The design of a maximum power point tracking (MPPT) on DC converter controller is presented in this article for a system. Fractional Order-Proportional Integral Derivative (FO-PID) and Parallel Distributed Compensation-Proportional Integral Derivative (PDC-PID) controllers have been implemented to the system converter as a proposed control approach. Particle Swarm Optimization (PSO) is used as optimization technique for determining the optimal parameters of (FO-PID) and (PDC-PID) controllers for tracking the output voltage from trained Adaptive Neuro Fuzzy Inference System (ANFIS) that is corresponding to maximum power generated from (PV) module. The PV system with the dynamic load is modeled and simulated by using the MATLAB/Simulink environment. The system performance is displayed in the form of a family of curves under different operating conditions

    ACUTE TOXICITY OF DIFFERENT SIZES OF SILVER NANOPARTICLES INTRAPERITONALLY INJECTED IN BALB/C MICE USING TWO TOXICOLOGICAL METHODS

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    Objective: This study aimed to evaluate the acute toxicity of intraperitoneally administrated silver nanoparticles (AgNPs) with different particle sizes in BALB/c mice.Methods: Citrate-capped AgNPs were prepared by citrate reduction method and isolated into small particles (average size 20 nm) and large particles (average size 50 nm). The median lethal dose (LD50) of 20 nm and 50 nm AgNPs was estimated using two toxicological methods, classical Dixon's up-and-down method and AOT425statPgm method for up-and-down procedure.Results: The LD50 was evaluated at the dosage level of 169 and 213.8 mg/kg, respectively for 20 nm AgNPs and at the dosage level of 354 and 391.5 mg/kg, respectively for 50 nm AgNPs. The results showed that LD50 obtained by the AOT425statPgm method was in accord with that of the Dixon's method and no significant differences between them (P = 0.06). The size 20 nm AgNPs were more toxic than the size 50 nm AgNPs. The behavioural responses and deviations were dose dependent, increasing by increasing the dose. The anatomical examinations showed that AgNPs were mainly accumulated in liver and spleen of dosed mice.Conclusion: The results suggested that the AOT425statPgm method was an efficient tool and a good alternative method for use in future acute toxicity studies.Â
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