Selection of High Affinity Peptides Against Hepatitis B Core Antigen from a Phage-Displayed Cyclic Peptide Library

Hepatitis B virus is the prototype member of the family Hepadnaviridae which causes acute and chronic liver diseases worldwide. The viral nucleocapsid containing a partially double stranded DNA is surrounded by an envelope comprises three distinct but related surface proteins (HBsAg), termed as small (S), medium (M) and large (L)-HBsAg. The essential subunit of the nucleocapsid is a polypeptide comprising 183 amino acids known as core protein (HBcAg). HBcAg produced in Escherichia coli is capable of self-assembly into core-like particles and can be purified easily with ammonium sulphate precipitation and sucrose gradient centrifugation. Core particles make of full-length HB cAg were used as substrate in biopanning with a cysteine constrained phage-displayed heptapeptide library. The most frequently identified phage clones displayed the cyclic peptides C-WSFFS NI-C and C-WPFWGPW-C. The relative dissociation constant (Krl) values for the interaction between the p hages and HBcAg were determined by an equilibrium binding assay in solution. The Kiel values for phage bearing peptides C-WSFFSNI-C and C-WPFWGPW-C for full-length and truncated HBcAg are less than 10 and 30 nM, respectively, which are 17- and 7- fold stronger than that of phage bearing the l inear peptide LLGRMK. The selected phages were able to compete with monoclonal antibody C 1-5 for a binding site on the surface of core particles, suggesting that the docking site of these phages may partially overlap with the epitope of mAb C 1-5, which was mapped at amino acid positions 78 to 83 at the tips of the core particles. The heavy chain of mAb C l-5 is hydrophobic and was proposed to be the contact region for HBcAg. Interestingly, the isolated peptides C-WSFFS NI-C and C-WPFWGPW-C are mainly composed of hydrophobic amino acids and may bind to the same region as mAb C l-5. A synthetic linear peptide bearing the sequence WSFFSNI inhibited the binding of L-HBsAg to core particles in vitro with an inhibition concentration (IC₅₀) approximately 9.8 µM. The additional of cysteine residues to both the N- and C-termini of the peptide greatly reduced the solubility of this cyclic peptide, and as a result the IC₅₀ is approximately 20-fold higher than that of WSFFSNI. A suitable recombinant carrier therefore is needed in order to reduce the hydrophobicity of the peptides and subsequently acts as a deli very system for targeting the peptide to virally infected cells

The effect of slurry composition on the microstructure and mechanical properties of open-cell Inconel foams manufactured by the slurry coating technique

Open-cell nickel-based alloy foams are attractive materials for applications such as sound damping and heat exchange, especially those involving exposure to high temperature environments. This study demonstrated the potential of a developed slurry coating technique for manufacturing open-cell Inconel alloy foams, and then investigated the effect of slurry composition on the microstructure and mechanical properties of the foams. It was found that the compressive properties of the foam can be quantitatively related to its relative density using the empirical equations. The deformation behaviour of the foam is bending-dominated; and unit cell struts undergo brittle fracture after the elastic region. Increasing the slurry solid loading leads to a higher average bulk foam density and more non-uniform crush bands in the foam under compression. Compared to other fabrication processes, this slurry coating technique is able to produce open-cell Inconel foams with relatively higher strength-to-weight ratios. This study also revealed that the sound absorption capability of the foam increases when its unit cell size is reduced

Two-channel linear phase FIR QMF bank minimax design via global nonconvex optimization programming

In this correspondence, a two-channel linear phase finite impulse response (FIR) quadrature mirror filter (QMF) bank minimax design problem is formulated as a nonconvex optimization problem so that a weighted sum of the maximum amplitude distortion of the filter bank, the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter is minimized subject to specifications on these performances. A modified filled function method is proposed for finding the global minimum of the nonconvex optimization problem. Computer numerical simulations show that our proposed design method is efficient and effective

Optimal cosine modulated nonuniform linear phase FIR filter bank design via stretching and shifting frequency response of prototype filter

This paper proposes an optimal cosine modulated nonuniform linear phase finite impulse response (FIR) filter bank design. The frequency responses of all the analysis filters and the synthesis filters of the filter bank are derived based on both stretching and shifting the frequency response of the prototype filter. The total aliasing error of the filter bank is minimized subject to a specification on the maximum amplitude distortion of the filter bank as well as specifications on both the maximum passband ripple magnitude and the maximum stopband ripple magnitude of the prototype filter. This filter bank design problem is actually a functional inequality constrained optimization problem. Our recently developed integration approach is employed for solving the problem. Computer numerical simulation results show that our proposed design method outperforms existing design methods

Minimax passband group delay nonlinear FIR filter design without imposing desired phase response

In this paper, a nonlinear phase finite impulse response (FIR) filter is designed without imposing a desired phase response. The maximum passband group delay of the filter is minimized subject to a positivity constraint on the passband group delay response of the filter as well as a specification on the maximum absolute difference between the desired magnitude square response and the designed magnitude square response over both the passband and the stopband. This filter design problem is a nonsmooth functional ine-quality constrained optimization problem. To tackle this problem, first, the one norm functional inequality constraint of the optimization problem is approximated by a smooth function so that the nonsmooth functional inequality con-strained optimization problem is approximated as a noncon-vex functional inequality constrained optimization problem. Then, a modified filled function method is applied for find-ing the global minimum of the nonconvex optimization prob-lem. Computer numerical simulation results show that our designed nonlinear phase peak constrained FIR filter could achieve lower minimum passband group delay than those of existing designs

Towards Self-Awareness Privacy Protection for Internet of Things Data Collection

The Internet of Things (IoT) is now an emerging global Internet-based information architecture used to facilitate the exchange of goods and services. IoT-related applications are aiming to bring technology to people anytime and anywhere, with any device. However, the use of IoT raises a privacy concern because data will be collected automatically from the network devices and objects which are embedded with IoT technologies. In the current applications, data collector is a dominant player who enforces the secure protocol that cannot be verified by the data owners. In view of this, some of the respondents might refuse to contribute their personal data or submit inaccurate data. In this paper, we study a self-awareness data collection protocol to raise the confidence of the respondents when submitting their personal data to the data collector. Our self-awareness protocol requires each respondent to help others in preserving his privacy. The communication (respondents and data collector) and collaboration (among respondents) in our solution will be performed automatically

Treatment of trigeminal neuralgia: role of radiofrequency ablation

Trigeminal neuralgia (TN) is a neuropathic pain condition affecting the face. It has a significant impact on the quality of life and physical function of patients. Evidence suggests that the likely etiology is vascular compression of the trigeminal nerve leading to focal demyelination and aberrant neural discharge. Secondary causes such as multiple sclerosis or brain tumors can also produce symptomatic TN. Treatment must be individualized to each patient. Carbamazepine remains the drug of choice in the first-line treatment of TN. Minimally invasive interventional pain therapies and surgery are possible options when drug therapy fails. Younger patients may benefit from microvascular decompression. Elderly patients with poor surgical risk may be more suitable for percutaneous trigeminal nerve rhizolysis. The technique of radiofrequency rhizolysis of the trigeminal nerve is described in detail in this review

Optimum nonuniform transmultiplexer design

This paper considers an optimum nonuniform FIR transmultiplexer design subject to specifications in the frequency domain. Our objective is to minimize the sum of the ripple energy for all the individual filters, subject to the specifications on amplitude and aliasing distortions, and to the passband and stopband specifications for the individual filters. This optimum nonuniform transmultiplexer design problem can be formulated as a quadratic semi-infinite programming problem. The dual parametrization algorithm is extended to the design of this nonuniform transmultiplexer problem. If the lengths of the filters are sufficiently long and the set of decimation integers is compatible, then our algorithm guarantees that the solution obtained will give rise to the global minimum, and the required specifications are satisfied

Optimal design of nonuniform FIR transmultiplexer using semi-infinite programming

This paper considers an optimum nonuniform FIR transmultiplexer design problem subject to specifications in the frequency domain. Our objective is to minimize the sum of the ripple energy for all the individual filters, subject to the specifications on amplitude and aliasing distortions, and to the passband and stopband specifications for the individual filters. This optimum nonuniform transmultiplexer design problem can be formulated as a quadratic semi-infinite programming problem. The dual parametrization algorithm is extended to this nonuniform transmultiplexer design problem. If the lengths of the filters are sufficiently long and the set of decimation integers is compatible, then a solution exists. Since the problem is formulated as a convex problem, if a solution exists, then the solution obtained is unique and the local solution is a global minimum

Transcriptomic changes in the root of oil palm (Elaeis guineensis Jacq.) upon inoculation with Bacillus sphaericus UPMB10

Plant growth-promoting bacteria (PGPB) promote plant growth through a combination of mechanisms which affect mineral nutrition and root development. In this study, we profiled the transcripts in oil palm roots inoculated with a PGPB, Bacillus sphaericus UPMB10, upon the establishment of a stable inoculum on the root surface by cDNA microarray analysis. A total of 70 from more than 3,700 transcripts examined were found to be significantly upregulated in the roots of oil palm inoculated with B. sphaericus UPMB10 compared to those from un-inoculated oil palm roots. Majority of these genes were related to protein synthesis and processing, stress, primary metabolism, and membrane transport. Many ribosomal proteins were upregulated in the roots of B. sphaericus-inoculated oil palm plantlets. In addition, B. sphaericus UPMB10 were able to upregulate the expression of a gene encoding low affinity nitrate transporter, independent of root morphogenesis. These rhizosphere bacteria were also demonstrated to induce stress-related proteins that may lead to tolerance to biotic and abiotic stresses