Physicochemical characterization of diclofenac sodium-loaded poloxamer gel as a rectal delivery system with fast absorption

Rectal poloxamer gel systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and were mucoadhesive to the rectal tissues without leakage after the dose. However, a poloxamer gel containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a poloxamer gel using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers, and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the poloxamer gel was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The poloxamer gels with less than 1.0% sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage, and were retained in the rectum of rats for at least 6 hr. Furthermore, poloxamer gel gave significantly higher initial plasma concentrations and faster T_max of diclofenac sodium than did solid suppository, indicating that drug from poloxamer gel could be absorbed faster than that from the solid one in rats. Our results suggested that a rectal poloxamer gel system with sodium chloride and poloxamers was a more physically stable, convenient, and effective rectal dosage form for diclofenac sodium.     

Spatial and Temporal Resolution of Conjugate Conduction-Convection Thermal Resistance

A transient, 3-D solution to the heat conduction equation with a small square heat source on an adiabatic surface and Newtonian convection on the opposite side was obtained using Green's functions. The geometry conservatively models conduction spreading resistance encountered by small, concentrated heat sources such as light-emitting diodes and integrated circuits in general, mounted to larger substrates such as the base of a heat sink experiencing Newtonian convection. The solution is presented for a range of nondimensional parameters. Superposition techniques can also be used to extend the applicability of the current solution to the temperature prediction of arbitrary heat flux patterns in certain cases. This technique only holds for applications where the heat transfer coefficient is not a function of temperature, such as thermal management strategies designed to rely on forced convection with air.     

Synthesis,characterization and application of biopolymer-ionic liquid composite membranes

Biopolymer composite membranes based on chitosan doped with an ionic liquid (IL) 1-ethyl 3-methylimidazolium thiocyanate (EMImSCN) have been developed and characterized. The doped ionic liquid films show remarkable enhancement in ionic conductivity (σ). The Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and X-ray diffraction studies (XRD) affirmed the composite nature, good incorporation of ionic liquid and reduction in crystallinity of films, respectively. The interaction between ionic liquid, chitosan and iodide polymer electrolyte matrix was evaluated by cyclic voltammetry. The fabricated dye sensitized solar cell (DSSC) using this new biopolymer electrolyte membranes shows promising performance.     

The cooking qualities of microwave oven cooked instant noodles

Deep‐fried instant noodles were cooked in a microwave oven at 557 W (medium power) and 657 W (full power). The microwave cooking times were determined based on textural parameters and the qualities of microwave oven cooked noodles at medium power and full power were compared with those of products cooked using a conventional gas stove for 9.1 min (CON). Heating in the microwave increased the temperature of the noodle block faster than the cooking water, led to an increased degree of gelatinisation of instant noodles, and reduced the cooking times to 8.5 min (medium power) and to 7.5 min (full power). Cooking in the medium power microwave resulted in high water absorption and weak hardness values. Cooking in the full power microwave resulted in higher hardness and tensile strength than the medium power microwave and sensory evaluated organoleptic scores were comparable to the CON, despite having a significantly higher rancidity.     

Preparation of Mn−Zn ferrite from spent zinc-carbon batteries by alkali leaching,acid leaching and Co-precipitation

The treatment of spent zinc-carbon batteries for the recovery of valuable metals followed by conversion to Mn−Zn ferrite has been conducted employing two-stage alkali and acid leaching and co-precipitation method. In the first stage, leaching process was carried out with 4 M NaOH, which resulted in a recovery of 63.4 %Zn and 0.1% Mn. Electrowinning of alkali leaching solution containing 12.75 g/L Zn at a current density of 0.2 A/cm² produced Zn metal of 15 nm to 30 nm size and 99.9% purity. The second stage leaching of residue with 3 M H₂SO₄ and 6 vol.% H₂O₂ at a solid/liquid ratio of 1∶10 indicated the leaching efficiency of 98.0% Zn, 97.9% Mn and 55.2% Fe. The obtained leaching solution was finally adjusted to suitable mole ratios of Mn∶Zn∶Fe (1∶1∶4) by the addition of Zn and Fe sulfate salts followed by pH control to produce Mn−Zn ferrite powder. The characterization of the ferrite powder showed uniform nano-crystalline particles of about 20 nm size with spinel structure.     

Hybrid ring coupler for W-band MMIC applications using MEMS technology

The hybrid ring coupler was designed and fabricated on a GaAs substrate using surface micromachining techniques, which adopted dielectric-supported air-gapped microstrip line (DAML) structure. The fabrication process of DAML is compatible with the standard monolithic microwave integrated circuit (MMIC) techniques, and the hybrid ring coupler can be simply integrated into a plane-structural MMIC. The fabricated hybrid ring coupler shows wideband characteristics of the coupling loss of 3.57 /spl plusmn/ 0.22dB and the transmission loss of 3.80 /spl plusmn/ 0.08dB across the measured frequency range of 85 to 105GHz. The isolation characteristics and output phase differences are -34dB and 180/spl plusmn/1/spl deg/, at 94GHz, respectively.     

Pressure casting of a zirconia-toughened alumina fiber-reinforced NiAl composite

A pressure-cast NiAl composite reinforced with polycrystalline alumina (PRD-166) fibers containing 0.2 weight fraction of partially stabilized zirconia was examined by optical and transmission electron microscopy (TEM). Fibers in the preform used for casting were forced into contact, and fiber bonding occurred in a number of instances. Fiber volume fraction was increased from an initial value of 0.4 to 0.6 as a consequence of the applied pressure. An explanation is offered for the interaction of applied pressure, wetting angle, and the rigidity of the fiber preform on the final volume fraction of the fibers in the composite. At the fiber/matrix interface, the alumina was free of zirconia particles. It is proposed that alumina grain growth forced the zirconia into the molten NiAl, where it dissolved. As solidification took place, the concentration of zirconium in the molten NiAl increased to a point where zirconium reacted with alumina to form zirconia again.     

Threshold voltage instability characteristics of HfO2 dielectrics n-MOSFETs

In this paper, the threshold voltage instability characteristics of HfO₂ high-k dielectric are discussed. The results from various stress bias conditions including DC and AC with variations of frequency, duty cycle, and polarity provide additional insights into the intrinsic behavior and the trapping dynamics of high-k materials. A reduced threshold voltage shift was observed at higher frequency and lower duty cycle under AC positive unipolar stress compared to DC stress. Similarly, the degradation of maximum transconductance was also reduced with AC stress. However, subthreshold swing changes were found to be negligible and fairly independent of stress frequencies and duty cycles under AC positive unipolar stress.When different polarity of stress, such as positive, negative, and bipolar stress was applied, it was observed that frequency and duty cycle dependencies were still valid in all three conditions. In contrast to positive stress, negative stress showed a decrease in the threshold voltage shift. Bipolar stress resulted in the highest threshold voltage instability, but the degradation in transconductance and subthreshold swing was actually smaller than those in negative unipolar stress. The bulk trap of HfO₂ dielectric, which is proportional to its physical thickness, is believed to be the primary factor for threshold voltage shift. AC unipolar operation would allow a higher 10-year lifetime operating voltage than the DC condition. In addition to experimental results, a plausible mechanism has been proposed.     

Cyanate Ester-Based Encapsulation Material for High-Temperature Applications

Cyanate ester resin-based composite materials have been proposed as potential encapsulants for high-temperature applications. The objective of this study is to develop a cyanate ester-based encapsulant, which can also serve as a flip-chip underfill as well as for traditional encapsulation. Two different materials, quartz and alumina fillers, have been studied. The impact of shapes and sizes of the fillers on the overall thermomechanical properties has been investigated. The adhesion strengths of the materials to the ceramic substrate, Kovar lid, and silicon die have also been characterized. The modulus of the resin and the shape of the fillers play a pivotal role in minimizing thermal stress, generated by coefficient of thermal expansion mismatches. Smaller filler particles were found to have better adhesion to the cyanate ester resin. The high-temperature performance of the cyanate ester-based encapsulants was evaluated by thermal aging at 300°C for up to 500 h.     

No wiring constraints

Wireless technologies are gaining increased acceptance as a viable technology within the industrial solution space. However, it is important for control system architects to fully understand not only the benefits but also the challenges and limitations of wireless technologies. The complex interrelationships between the various wireless technology characteristics require careful tradeoffs to be made in the design of the solution. This is especially true for applications that need to handle continuous data streams where high capacity is critical to maintain the scalability and reliability of the network. Although still relatively new, mesh networks have proven themselves to have significant advantages in robustness, scalability, and low-power consumption over other wireless technologies for use in industrial monitoring applications. Mesh networks employing PDR address the scalability challenges of wireless sensor networking that can limit implementation in production situations by significantly increasing overall packet-delivery rate and reducing network communication overhead. HC_WSN, an approach that will emerge as the important next trend in the wireless sensor networking industry, can be implemented in addition to PDR techniques and will further support the increasing number of applications that require the wireless sensor network to handle greater amounts of data.