Recent advances in wireless networking

After discussing advances in wired networking in a previous column (see ibid., p.107-9, April 2000), I now turn to advances in wireless networking. Wireless networks can include everything from cellular, personal communications system (PCS), and Group System for Mobile communications (GSM) networks to wireless LANs, satellite-based networks, and fixed wireless networks. Many of these technologies have experienced significant growth lately because of an increasingly mobile workforce and accelerating user acceptance     

Control of time-dependent effects in steel-concrete composite frames

Studies are presented for the control of time-dependent effects of creep and shrinkage in steel-concrete composite frames with pre-cast concrete slab for both shored and un-shored constructions. A developed hybrid procedure has been used for carrying out the studies. The procedure accounts for creep, shrinkage and progressive cracking in concrete slab panels. Two frames, a single storey and a five storey frame are considered. It is shown that, for both the types of constructions, shored and un-shored, the increase in bending moments and mid-span deflections can be controlled to a significant degree, without putting constraints on design parameters, by simply delaying the time of mobilization of composite action between the pre-cast concrete slab panels and the steel section. It is also found that though there is insignificant effect of type of construction on bending moments, the percentage change in mid-span deflection due to creep and shrinkage is significantly higher for shored construction.     

Synthesis,characterization and surface modification of ZnCrFeO4 nanoparticles

The aim of this research was to investigate zinc chromium ferrite (ZnCrFeO₄) nanoparticles, synthesized using the sol gel technique with nanoparticle size controlled through a two-stage annealing process. Stage one was a low temperature firing which produced low quality nanocrystals with an average size of 15 nm. This was followed by a second firing stage at high temperature which enhanced the crystal quality. The nanoparticles were then coated with a bio-compatible shell to form a stable suspension in the ferrofluid carrier. The resulting nanoparticles were found by electron microscopy, atomic force microscopy and X-ray diffraction studies to have excellent crystal quality. The average size was 8.5 nm. Preliminary cell culture studies indicated the ZnCrFeO₄ nanoparticles were non-toxic. The relatively high measured value of the relaxivity r₂ showed that the nanoparticle coating was effective in substantially reducing aggregation and enhancing the properties of the nanoparticles associated with contrast enhancement in MRI.     

Chemopreventive Effect of Different Ratios of Fish Oil and Corn Oil in Experimental Colon Carcinogenesis

n-3 Polyunsaturated fatty acids (PUFA) have a chemopreventive effect while n-6 PUFA promote carcinogenesis. The effect of these essential fatty acids may be related to oxidative stress. Therefore, the study was designed to evaluate the effect of different ratios of fish oil (FO) and corn oil (CO) in the prevention of colon cancer. Male Wistar rats were divided into control, dimethylhydrazine dihydrochloride (DMH) treated, FO + CO (1:1) and FO + CO (2.5:1). All the groups, except the control received a weekly injection of DMH for 4 weeks. The animals were sacrificed either 48 h later (initiation phase) or kept for 16 weeks (post initiation phase). DMH treatment in the initiation phase animals showed mild to moderate inflammation, decreased ROS and TrxR activity, increased antioxidants, apoptosis and ACF multiplicity. The post initiation study showed severe inflammation with hyperplasia, increased ACF multiplicity and ROS levels, a decrease in antioxidants and apoptosis. The FO + CO (1:1) treated animals showed severe inflammation, a decrease in ROS, an increase in antioxidants and apoptosis in the initiation phase. FO + CO (1:1) in the post initiation phase and FO + CO (2.5:1) in the initiation showed mild inflammation, increased ROS, apoptosis and decreased antioxidants. There was a decrease in ACF multiplicity and ROS levels, increased antioxidants and apoptosis in the post initiation phase study. The present study suggests that FO has a dose- and time-dependent chemopreventive effect in colon cancer mediated through oxidative stress and apoptosis.     

Tunable Terahertz Circularly Polarized Dielectric Resonator Antenna with the Higher Order Modes

Silicon - A tunable terahertz (THz) dielectric resonator (DR) antenna (DRA) with circular polarization operating with multiple higher order modes is numerically studied and implemented. A...     

Novel framework for secured bulk creation of virtual machine in IaaS platform

Software Quality Journal - Cloud service providers (CSPs) like Amazon Web Services, Google Engine, and Microsoft Azure have the major share in providing cloud-related services globally. Their...     

Biohybrid Design Gets Personal: New Materials for Patient-Specific Therapy

Precision medicine requires materials and devices that can sense and adapt to dynamic physiological and pathological conditions. This motivates the design and manufacture of biohybrid materials that mimic the responsive behaviors demonstrated by natural biological systems. Two parallel approaches to biohybrid design are presented—biomimetics and biointegration. Biohybrid hydrogels that mimic the form and function of natural materials, or that integrate living cells or bioactive moieties, can respond to a range of environmental stimuli in parallel, including heat, light, pH, hydration, enzymes, and electric, mechanical, and magnetic forces. A range of examples that illustrate the tremendous potential of this nascent discipline are presented, and ongoing technical challenges related to manufacturing, storage, transport, and external noninvasive control of these materials that will need to be overcome in the coming years are outlined. The ethical, educational, and regulatory challenges that will govern translation of biohybrid design into medical applications are also discussed. Personalized medical therapies that target the precise needs of patients are a critically needed and expanding market. Biohybrid design offers the unique ability to manufacture materials and devices that match the dynamic and patient-specific in vivo environment, promising to generate more effective and safe therapies that enable personalized care.