Chitosan particles agglomerated scaffolds for cartilage and osteochondral tissue engineering approaches with adipose tissue derived stem cells

In the XML file of the original article, H. Redl’s affiliation is incorrect. It is listed correctly in both the paper and PDF versions of the article, and can be found below: The online version of the original article can be found at     

An ultrasonic obstacle detector based on phase beamforming principles

A prototype of an ultrasonic obstacle detector developed as a part of a navigation system for blind and visually impaired people is presented. The detector, which employs a single ultrasound source and an array of microphones, determines the distance to the obstacle by measuring time between sending the pulse and receiving the reflected signal. Using the phase beamforming technique, borrowed from hydroacoustics, to process the output signals of microphones, it determines also the direction from which the reflected signal is received, thereby locating the obstacle. The obstacle detector was subjected to a series of tests in order to verify its design and to assess its ability to detect a broad range of obstacles. Presented test results show that most obstacles can be detected and recognized, and that the tested obstacle detector provides complete coverage of the safety zone in front of the user.     

Experimental determination of electron and hole mobilities in MOSaccumulation layers

This letter presents for the first time, the experimentally determined majority carrier mobilities in the accumulation layer of a MOSFET for both p-type and n-type channel doping for a wide range of doping concentrations. The measured carrier mobility is observed to follow a universal behavior at high transverse fields, similar to that observed for minority carriers in MOS inversion layers. At the higher doping levels, the effective mobility for majority carriers at low to moderate transverse fields is found to be very close to the bulk mobility. This is believed to be due to carrier screening of the ionized impurity scattering which dominates at the higher doping concentrations     

Arsenic deactivation enhanced diffusion and the reverseshort-channel effect

The effect of enhanced diffusion caused by the electrical deactivation of arsenic on the reverse short-channel effect (RSCE) in NMOS devices is investigated. A simple four-mask process was utilized to fabricate deep sub-micron NMOS devices. Source/drain (S/D) implant and anneal conditions were varied in order to determine their implications on the RSCE. Results indicate that when high concentrations of arsenic deactivate, enhanced diffusion occurs, leading to significantly more RSCE. This implies that the dose of the arsenic implant and the subsequent anneals should be carefully considered in source/drain engineering     

Channel sharing in multi-hop WDM lightwave networks: realizationand performance of multicast traffic

A local lightwave network can be constructed by employing two-way fibers to connect nodes in a passive-star physical topology, and the available optical bandwidth may be effectively accessed by the nodal transmitters and receivers at electronic rates using wavelength division multiplexing (WDM). The number of channels, ω, in a WDM network is limited by technology and is usually less than the number of nodes, N, in the network. We provide a general method using channel sharing to construct practical multi-hop networks under this limitation. Channel sharing may be achieved through time division multiplexing. The method is applied to a generalized shuffle-exchange-based multi-hop architecture, called GEMNET. Multicasting-the ability to transmit information from a single source node to multiple destination nodes-is becoming an important requirement in high-performance networks. Multicasting, if improperly implemented, can be bandwidth-abusive. Channel sharing is one approach toward efficient management of multicast traffic. We develop a general modeling procedure for the analysis of multicast (point-to-multipoint) traffic in shared-channel, multihop WDM networks. The analysis is comprehensive in that it considers all components of delay that packets in the network experience-namely, synchronization, queuing, transmission, and propagation. The results show that, in the presence of multicast traffic, WDM networks with ω相似文献   

What should medical decision be based on?

Medical decision making is basically related to three criteria: 1) estimated effectiveness in terms of objective and subjective results: 2) equity related to the concept of justice in the societal context; 3) legitimacy according to the willingness to pay of the society, its resource availability and the fraction of its income that is allowed to be spent for health care. A worsening dilemma is unescapable between a utilitarian medical project, and the traditional hippocratic rule of rescue no matter what the cost may be. Every care taker should be involved to give a clear account of medical decision in order to generate and adopt some acceptable view for a reliable implementation with respect to equity and justice.     

Metabolic activation and inactivation of metanil yellow and orange II in the Salmonella typhimurium his-reversion assay.

Among a variety of experimental protocols used, the combined use of 0.5% dextrose in bottom agar and 1 micromol of flavin mononucleotide (FMN) in preincubation mixtures without fraction S9 mix resulted in the highest level of induced Salmonella typhimurium his reversions with both dyes metanil yellow and orange 11 with strain TA100. Strain TA98 yielded notably lower levels of reversions under the same conditions. The presence of uninduced hamster liver S9 fraction resulted in a weak mutagenic response while Aroclor 1254-induced rat liver S9 fraction resulted in the complete absence of mutagenicity with both strains and with both dyes.