Application of ameliorated Harris Hawks optimizer for designing of low-power signed floating-point MAC architecture

Neural Computing and Applications - Recently established Harris Hawks optimization (HHO) has natural behaviour for finding an optimum solution in global search space without getting trapped in...     

Immune response against the non-repeat region (293-310) of the circumsporozoite protein of Plasmodium vivax

Immunization by peptides based on the repeat sequences of Plasmodium falciparum or P. vivax antigen(s) have shown inconsistent results during clinical trials in humans. This could be attributed to the lack of T-cell help or antigenic polymorphism. Thus, attention has been focused towards the more conserved non-repeat regions. The present study was undertaken to map the antigenic determinant in the vicinity of region II (outside the repeat) of CS protein of P. vivax. The immunogenicity of the peptide was studied alone and after linking with polytuftsin (PT), using alum and Freund's adjuvant, in inbred strains of mice with different genetic backgrounds. The humoral response and antigen induced T-cell proliferation assays clearly demonstrated the immunomodulatory activity of PT. Comparable results were observed with antigen(s) administered either in alum or Freund's adjuvant. The induction of IgG2a and IgG2b antibody isotypes by both, peptide as well as the conjugate, may indicate that the T-helper response involved is of Th1 type. Further the immunofluorescence studies have shown that antibodies recognized the air dried sporozoites of P. cynomolgi. The results thus show that the above sequence has overlapping B and T-cell determinants and that alum can be substituted for Freund's adjuvant in generating an effective immune response.     

Synthesis and structure-activity relationship of the isoindolinyl benzisoxazolpiperidines as potent,selective, and orally active human dopamine D4 receptor antagonists

A new class of potent dopamine D(4) antagonists was discovered with selectivity over dopamine D(2) and the alpha-1 adrenoceptor. The lead compound was discovered by screening our compound collection. The structure-activity relationships of substituted isoindoline rings and the chirality about the hydroxymethyl side chain were explored. The isoindoline analogues showed modest differences in potency and selectivity. The S enantiomer proved to be the more potent enantiomer at the D(4) receptor. Several analogues with greater than 100-fold selectivity for D(4) over D(2) and the alpha-1 adrenoreceptor were discovered. Several selective analogues were active in vivo upon oral or intraperitoneal administration. A chiral synthesis starting from either D- or L-O-benzylserine is also described.     

Shape forming of ceramics via gelcasting of aqueous particulate slurries

Gelcasting is a promising technique for shape forming of bulk dense or porous ceramic, metal structures. The process offers a number of advantages over processes such as slip casting, injection molding in forming complex ceramic shapes. It is shown here that the optimization of slurry rheology, choice of mold material, mold design and the drying conditions have a significant role in the overall success of the process. In this process, components of simple or complex shapes can be produced to near net shape by direct casting. If required complex shapes can also be produced by machining the green gelcast bodies. The process of gelcasting also has a lot of potential in forming highly porous ceramic shapes.     

Gravity-driven countercurrent two-phase flow during filling of an unvented vessel

Countercurrent two-phase flow associated with filling of sealed vessels via gravity-driven liquid injection through inclined channels was experimentally studied and analytically modeled. Experiments were performed using transparent tubular test sections connected at one end to the bottom of a large, open water tank, and at the other end to an unvented tank. The test section parameters (including the channel diameter (1.27–2.54cm), length (30.5–122 cm), angle of inclination with respect to horizontal plane (0–30°), and the empty volume in the sealed vessel) were systematically varied. Flow regimes in the test section were recorded and transient flow rates were measured during the experiments. Oscillatory, and intermittent stratified slug, were dominant flow regimes in most tests. The quasi-steady liquid superficial velocity in the test section was sensitive to the test section dimensions, and varied in the range 0.04–0.95 m s⁻¹. These flow regimes were mechanisally modeled. The models are shown to satisfactory predict the measured hydrodynamic parameters.     

A policy based framework for quality of service management in software defined networks

Growth in multimedia traffic over the Internet increases congestion in the network architecture. Software-Defined Networking (SDN) is a novel paradigm that solves the congestion problem and allows the network to be dynamic, intelligent, and it centrally controls the network devices. SDN has many advantages in comparison to traditional networks, such as separation of forwarding and control plane from devices, global centralized control, management of network traffic. We design a policy-based framework to enhance the Quality of Service (QoS) of multimedia traffic flows in a potential SDN environment. We phrase a max-flow-min-cost routing problem to determine the routing paths and presented a heuristic method to route the traffic flows in the network in polynomial time. The framework monitors the QoS parameters of traffic flows and identifies policy violations due to link congestion in the network. The introduced approach dynamically implements policy rules to SDN switches upon detection of policy violations and reroutes the traffic flows. The results illustrate that the framework achieves a reduction in end-to-end delay, average jitter, and QoS violated flows by 24%, 37%, and 25%, respectively, as compared to the Delay Minimization method. Furthermore, the proposed approach has achieved better results when compared to SDN without policy-based framework and reduced end-to-end delay, average jitter, and QoS violated flows by 51%, 62%, and 28%, respectively.

     

Steady state and transient photoconductivity measurements in a-Se90 − xSb10Inx thin films

Amorphous thin films of Se_90 − xSb₁₀In_x (0 ≤ x ≤ 15) have been prepared by electron beam evaporation method. The steady state and transient photoconductivity measurements on the thin films of Se_90 − xSb₁₀In_x (0 ≤ x ≤ 15) were carried out at different levels of light intensities (500 lx-5000 lx) at room temperature (301 K). The plot of photocurrent (I_ph) versus light intensity (F) follows a power law I_ph ∝ F^γ. The value of exponent γ lies between 0.5 and 1.0, which indicates there exists a continuous distribution of localized states in the mobility gap of Se_90 − xSb₁₀In_x (0 ≤ x ≤ 15) thin films. For transient photoconductivity, when the samples were illuminated with light, the photocurrent reaches the maximum value during the first 5 s of exposure time and thereafter, it starts decreasing and becomes stable after 15 min of exposure. This kind of phenomenon is termed as photo-degradation of photocurrent. The results have been explained on the basis of charged defect model and the intercluster interaction model. The magnitude of photocurrent of the system a-Se₇₅Sb₁₀In₁₅ is higher than the parent system a-Se₉₀Sb₁₀. The photosensitivity shows a minimum value at 5 atomic percentage of indium (In) concentration, which is explained based on chemically ordered network model and the topological model.