97 research outputs found

    Dual Key Speech Encryption Algorithm Based Underdetermined BSS

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    When the number of the mixed signals is less than that of the source signals, the underdetermined blind source separation (BSS) is a significant difficult problem. Due to the fact that the great amount data of speech communications and real-time communication has been required, we utilize the intractability of the underdetermined BSS problem to present a dual key speech encryption method. The original speech is mixed with dual key signals which consist of random key signals (one-time pad) generated by secret seed and chaotic signals generated from chaotic system. In the decryption process, approximate calculation is used to recover the original speech signals. The proposed algorithm for speech signals encryption can resist traditional attacks against the encryption system, and owing to approximate calculation, decryption becomes faster and more accurate. It is demonstrated that the proposed method has high level of security and can recover the original signals quickly and efficiently yet maintaining excellent audio quality

    Mismatch negativity in chronic tension-type headache with and without medication-overuse

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    Abstract Background: It is unknown if medication-overuse headache, clinically similar to chronic tension-type headache, has pre-attentive problems which may be related to pain or substance abuse. Methods: Auditory frequency deviance elicited mismatch negativity was recorded from 22 patients with chronic tension-type headache, 26 with medication-overuse headache from underlying chronic tension-type headache and 41 healthy volunteers as controls. Their depression and anxiety scores were noted. Results: There were no signifi cant differences in the N1 latency or amplitude to both standard and deviant stimuli for the different groups. However, the latency and amplitude of mismatch negativity were signifi cantly shortened and reduced at Fz, Cz, and Pz in medication-overuse headache as compared to chronic tension-type headache and normal subjects. Anxiety levels were elevated in chronic tensiontype headache and medication-overuse headache subjects compared to healthy controls but were not correlated with mismatch negativity latency or amplitude in a given group. Conclusions: In medication-overuse headache subjects, the shortened mismatch negativity latency indicates quick involuntary attention switching to auditory change, while its reduced amplitude indicates poor accuracy in discriminating early stimuli, which may be related to medication overuse rather than to the head pain experienced

    Genetic Polymorphisms in Enzymes Involved in One-Carbon Metabolism and Anti-epileptic Drug Monotherapy on Homocysteine Metabolism in Patients With Epilepsy

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    Aims: To investigate the effects of single nucleotide polymorphisms (SNPs) in genes of one-carbon metabolism (OCM) related enzymes and anti-epileptic drug (AED) monotherapy on homocysteine (Hcy) metabolism in patients with epilepsy, and to further explore specific SNPs that may increase patients' susceptibility to the effects of AEDs on the Hcy imbalance.Method: This case-control study analyzed 279 patients with epilepsy, including patients receiving monotherapy with valproate (VPA) (n = 53), oxcarbazepine (OXC) (n = 71), lamotrigine (LTG) (n = 55), or levetiracetam (LEV) (n = 35) and patients who had not taken any AEDs (controls, n = 65) for at least 6 months. Serum levels of vitamin B12 (vit B12), folate (FA) and Hcy were measured, and 23 SNPs in 13 genes of OCM-related enzymes were genotyped in all patients.Results: Methylenetetrahydrofolate reductase (MTHFR) rs1801133 was associated with elevated serum Hcy levels in patients with epilepsy (P < 0.001), and patients presenting the TT genotype exhibited higher serum Hcy levels than patients with the CC (P < 0.001) or CT (P < 0.001) genotype. A subsequent multiple linear regression analysis showed that AED monotherapy with VPA (vs. control: P = 0.023) or OXC (vs. control: P = 0.041), and genotypes of MTHFR rs1801133 TT (vs. CC: P < 0.001; vs. CT: P < 0.001), transcobalamin 2 (TCN2) rs1801198 CC (vs. GC: P = 0.039) and folate receptor 1 (FOLR1) rs2071010 AA (vs. GA: P = 0.031) were independent risk factors for higher Hcy levels. In the subgroup analysis of patients taking OXC, we found that patients with genotypes of MTHFR rs1801133 TT (vs. CC: P = 0.001; vs. CT: P < 0.001) and TCN2 rs1801198 CC (vs. GC: P = 0.021; vs. GG: P = 0.018) exhibited higher serum Hcy levels.Conclusions: VPA, OXC, and genotypes of MTHFR rs1801133 TT, TCN2 rs1801198 CC, and FOLR1 rs2071010 AA are all independent risk factors for elevated Hcy levels in patients with epilepsy. Moreover, genotypes of MTHFR rs1801133 TT and TCN2 rs1801198 CC may increase patients' susceptibility to the effect of OXC on disrupting Hcy homeostasis

    Cloning and Characterization of a Putative TAC1 Ortholog Associated with Leaf Angle in Maize (Zea mays L.)

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    BACKGROUND: Modifying plant architecture to increase photosynthesis efficiency and reduce shade avoidance response is very important for further yield improvement when crops are grown in high density. Identification of alleles controlling leaf angle in maize is needed to provide insight into molecular mechanism of leaf development and achieving ideal plant architecture to improve grain yield. METHODOLOGY/PRINCIPAL FINDINGS: The gene cloning was done by using comparative genomics, and then performing real-time polymerase chain reaction (RT-PCR) analysis to assay gene expression. The gene function was validated by sequence dissimilarity analysis and QTL mapping using a functional cleaved amplified polymorphism (CAP). CONCLUSIONS: The leaf angle is controlled by a major quantitative trait locus, ZmTAC1 (Zea mays L. Leaf Angle Control 1). ZmTAC1 has 4 exons encoding a protein with 263 amino acids, and its domains are the same as those of the rice OsTAC1 protein. ZmTAC1 was found to be located in the region of qLA2 by using the CAP marker and the F(2:3) families from the cross between Yu82 and Shen137. Real-time PCR analysis revealed ZmTAC1 expression was the highest in the leaf-sheath pulvinus, less in the leaf and shoot apical meristem, and the lowest in the root. A nucleotide difference in the 5'-untranslated region (UTR) between the compact inbred line Yu82 ("CTCC") and the expanded inbred line Shen137 ("CCCC") influences the expression level of ZmTAC1, further controlling the size of the leaf angle. Sequence verification of the change in the 5'-UTR revealed ZmTAC1 with "CTCC" was present in 13 compact inbred lines and ZmTAC1 with "CCCC" was present in 18 expanded inbred lines, indicating ZmTAC1 had been extensively utilized in breeding with regard to the improvement of the maize plant architecture

    Sirtuin 6 maintains epithelial STAT6 activity to support intestinal tuft cell development and type 2 immunity

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    Dynamic regulation of intestinal epithelial cell (IEC) differentiation is crucial for both homeostasis and the response to helminth infection. SIRT6 belongs to the NAD+-dependent deacetylases and has established diverse roles in aging, metabolism and disease. Here, we report that IEC Sirt6 deletion leads to impaired tuft cell development and type 2 immunity in response to helminth infection, thereby resulting in compromised worm expulsion. Conversely, after helminth infection, IEC SIRT6 transgenic mice exhibit enhanced epithelial remodeling process and more efficient worm clearance. Mechanistically, Sirt6 ablation causes elevated Socs3 expression, and subsequently attenuated tyrosine 641 phosphorylation of STAT6 in IECs. Notably, intestinal epithelial overexpression of constitutively activated STAT6 (STAT6vt) in mice is sufficient to induce the expansion of tuft and goblet cell linage. Furthermore, epithelial STAT6vt overexpression remarkedly reverses the defects in intestinal epithelial remodeling caused by Sirt6 ablation. Our results reveal a novel function of SIRT6 in regulating intestinal epithelial remodeling and mucosal type 2 immunity in response to helminth infection

    SERS property of Co complex on boron nitride nanosheets/silver nanoparticles aggregates and photophysical characterisation of interactions among Co complex ion-exchanged within zirconium phosphate

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    The Co(II) complex of [Co(bpy)2(NO3)]Cl·3H2O, bpy = 2,2'-bipyridine, has been synthesised by the solution crystallisation method. The boron nitride nanosheets/silver nanoparticles/[Co(bpy)2(NO3)]Cl·3H2O nanoaggregate was prepared in order to better analyse the adsorption orientation of the cobalt complex on the surface of silver nanoparticles. The result of the surface-enhanced Raman scattering measurement indicates that the molecular plane of the cobalt complex presents a tilted orientation with respect to the surface of silver nanoparticles. The luminescence property of [Co(bpy)2(NO3)]+ two-dimensional arrangements within the layers of zirconium phosphate (ZrP) was also investigated. Steady-state luminescence spectra of the [Co(bpy)2(NO3)]+-exchanged ZrP materials show an increase in the luminescence intensity

    A Communication Reliability Enhancement Framework for Wireless Sensor Network Using the ZigBee Protocol

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    This paper presents the framework that enhances the communication reliability of wireless sensor network using the ZigBee protocol. The paper begins with the introduction of common communication problems caused by the broken links between the sensor module and the message relay, or between different message-relays. Extra message handshake mechanisms are added to solve the mentioned problems. Based on the solution to different problems, a general purpose reliability enhancement framework is developed. The framework contains two state machines for both the sensor module and the massage relay. These two state machines can work together with the ZigBee protocol to enhance the network communication reliability. Moreover, the battery lifetime of the sensor module under link loss is considerably increased after the enhancement
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