Detection of HPV and ras gene mutations in cervical smears from female genital lesions

BACKGROUND: Recurrent hyperparathyroidism may occur following parathyroid autotransplantation due to autogenous function of the muscle-engrafted tissue. Parathyroid lesions are uncommonly diagnosed on cytology. CASE: A 31-year-old female with chronic renal failure presented with an elevated parathyroid hormone level and a neck mass in the left sternocleidomastoid muscle, the site of a previous parathyroid autograft. Fine needle aspiration of the mass revealed high cellularity, with perivascularly arranged, three-dimensional, branching clusters; individual cells; and naked nuclei exhibiting anisonucleosis. A diagnosis of parathyroid graft hyperplasia was made by fine needle aspiration and subsequently by histopathologic examination. CONCLUSION: Fine needle aspiration is an effective tool for confirming the presence of parathyroid autograft hyperplasia, thus allowing the correct surgical approach.     

On the application of adaptive antennas to microcellularenvironments: radio channel characteristics and system performance

The possible application of adaptive antennas in microcellular operational environments is studied in this paper with the help of a site-specific ray-tracing propagation model. First are examined the statistics of propagation parameters that play an important role for the performance of adaptive antennas. Particular emphasis is put on the spatial characteristics of the radio channel under line-of-sight (LOS) and non-LOS conditions. For this reason, area statistics are produced for a typical small-cell environment for parameters such as the number of multipath clusters, number of rays, angular size, and excess delay of each impulse response, as well as the number of rays, angular size and power of the multipath clusters. Results show that contrary to the common belief for such environments, the signal is not "almost" uniformly distributed in the spatial domain, instead is contained in a few narrow clusters. Then the effect of the microcellular environment on the uplink performance of some well-known techniques like conventional beamforming, maximum entropy, switched beams, maximum ratio and optimum combining, and beam-space optimum combining is examined . The results show that for typical time-division multiple-access (TDMA) scenarios with one and two users, the beam space optimum combining (strongest eigenvalue version) and the switched beams methods, offer the best performance     

Optimizing Radio Network Planning Evolution Towards Microcellular Systems

Wireless Personal Communications - Service demand in cellular radio networks is generally heterogeneous and non uniform, leading to asymmetrical topologies. This complexity along with the multiple...     

Fairness and Throughput Trade-Off Analysis for UMTS WCDMA Network Planning

The issue of fairness and throughput trade-off in universal mobile telecommunications system network planning based on wideband code division multiple access is discussed in this paper. The employed radio resource management (RRM) fully supports rate adaptation and hence, new potentials arise in terms of system throughput and fairness. The authors study four low complexity RRM algorithms that perform efficient rate adaptation in order to resolve typical operational bottlenecks that occur in a network environment (overloading, connection failure, etc.). Furthermore, a new hybrid approach that builds upon the aforementioned strategies is introduced. The results presented in the paper show that this technique enables the control of network performance towards throughput and fairness, according to the operational requirements in cellular and/or network level. Finally, random beamforming options are explored in the same context, and the respective results show that this technique penalizes users with good channel quality, thus providing higher system fairness.     

Adaptive Antennas for Microcellular and Mixed Cell Environments with DS-CDMA

Adaptive antenna technology is now regarded as one of the key system components in future generation cellular networks. This paper considers the performance of a DS-CDMA system which employs adaptive antennas at the base station sites of both microcell and mixed micro/umbrella cell operational environments. A microcellular ray tracing propagation tool has been employed in order to ascertain site specific propagation data. Results for a typical small cell environment highlight both the propagation characteristics and the behaviour of the adaptive antenna, as well as the sensitivity of the system upon parameters such as the mutual coupling effect. This work does not assume idealised propagation conditions or antenna radiation patterns for the small cell analysis.In summary, the results indicate that microcellular base stations employing adaptive antenna signal processing can offer a significant capacity enhancement and improved channel characteristics when compared with their omnidirectional counterparts. In addition, it is shown that umbrella cells overlaying microcells within the same RF bandwidth allocation, do not impact upon system capacity providing that adaptive antenna technology is employed at the umbrella cell site.     

Hydroxylated and methoxylated brominated diphenyl ethers in the red algae Ceramium tenuicorne and blue mussels from the Baltic Sea

Methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and hydroxylated PBDEs (OH-PBDEs) have recently been identified in fish and wildlife from the Baltic Sea. Both OH-PBDEs and MeO-PBDEs are known natural products, while OH-PBDEs also may be metabolites of PBDEs. The aim of the present study was to determine if the red macroalga Ceramium tenuicorne could be a source for MeO- and OH-PBDEs in the Baltic environment. Blue mussels (Mytilus edulis) from the same area were also investigated for their content of MeO- and OH-PBDEs. Seven OH-PBDEs and four MeO-PBDEs were present both in the red macroalga and the blue mussels. The mussels also contained a monochlorinated OH-tetraBDE. One of the compounds, 6-methoxy-2,2',3,4,4',5-hexabromodiphenyl ether, has never been reported to occur in the environment. The identification was based on comparison of relative retention times with reference standards, on two gas chromatographic columns of different polarities, together with comparisons of full-scan electron capture negative ionization (ECNI) and electron ionization (EI) mass spectra. It is shown that MeO-PBDEs and OH-PBDEs are present in algae, but at this stage it could not be confirmed if the compounds are produced by the alga itself or by its associated microflora and/or microfauna.     

Levels of PCBs and their metabolites in the serum of residents of a highly contaminated area in eastern Slovakia

The over-riding aim of the present investigation was to obtain information concerning exposure that can be used as a basis for studies on the health of individuals residing in the Michalovce area of eastern Slovakia which is heavily contaminated by polychlorinated biphenyls (PCBs). Accordingly, this work focused on determination of serum concentrations of hydroxylated (OH-PCBs) and methylsulfonyl-substituted (MeSO2-PCBs) metabolites of PCBs. One hundred and twenty-two men and women, 20-59 years of age, living in the contaminated area and 175 from the control Stropkov/Svidnik district were selected randomly from 2047 sampled individuals. Following a specially designed cleanup, the levels of various congeners of OH-PCBs and MeSO2-PCBs in their serum were quantitated by gas chromatography and mass spectrometry, with comparison to authentic reference standards. The median concentrations of PCB congeners and their OH-PCB and MeSO2-PCB metabolites were 2-3-fold higher in residents of Michalovce than in the control region. The levels of certain OH-PCB metabolites were in the same high range as those of individual PCB congeners, whereas the MeSO2-PCB levels were significantly lower. The PCB and their metabolites were present at slightly higher concentrations in men than in women, and the serum levels of PCBs and MeSO2-PCBs increased with increasing age. Thus, the environmental contamination resulting from previous industrial production of PCBs has led to elevated concentrations of PCBs and their metabolites in the serum of individuals living in the Michalovce area.     

OFDMA techniques in multicellular networks with total frequency reuse

Orthogonal frequency division multiple access (OFDMA) techniques are investigated in this paper. Five subchannel allocation algorithms are analysed and their performance in a multicellular environment is evaluated with simulations. Four schemes of lower complexity, suitable for the early deployment of wireless systems, are compared with a more computationally demanding scheme with respect to their blocking probability, loading factor and offered bit rate. The channel condition of each carrier is calculated and its knowledge is used for power controlled adaptive modulation, as an essential feature of the OFDMA technique. The general radio resource management process is divided into two steps: in the first step a base station allocates carriers to users while in the second step the modulation and power levels for each allocated carrier are defined.The simulation results demonstrate that a wireless system in its early deployment phase (up to 15–30% blocking probability) can employ simple OFDMA techniques capable of achieving high throughput. Furthermore, it is demonstrated that two of the proposed lower complexity schemes, (those based on cell coordination), offer good performance gain for higher data rate services. Nevertheless, these schemes achieve relatively lower gains with adaptive modulation, when compared with the techniques which exploit interference averaging or adaptive interference mitigation.     

Investigation into the sensitivity of the power predictions of amicrocellular ray tracing propagation model

This paper investigates the sensitivity of the three-dimensional (3-D) ray tracing microcellular model presented in Astanasiadou et al. (1995, 2000). The variation of the received power is examined for different ray permutations, wall characteristics, antenna position offsets and database inaccuracies. Predictions of the different configurations in line-of-sight (LOS), non-LOS (NLOS), and deep shadow areas are compared with each other and also with narrowband measurements. The analysis illustrates that although the model produces reliable results with five orders of reflection and one order of diffraction, higher orders of reflection and double diffracted rays enhance the model's performance in deep shadow areas. It is also shown that good agreement with measured results can be obtained for wall conductivity in the order of 10^-3 S/m and values of relative permittivity around five. The sensitivity analysis to the antenna positioning and database inaccuracies indicates that the receiver positions which suffer the highest power deviations are those at the boundaries of the LOS areas, as well as the positions in the deep shadow regions. In general, for antenna offsets up to 1 m, the predictions of the model are not significantly affected. Finally, the building databases with 1m maximum displacement do not have severe effects on the predictions, but databases with less accuracy can seriously degrade the performance of the model     

Performance of OFDMA Multicell Systems with Opportunistic Beamforming

The opportunistic beamforming (OB) technique in multicellular OFDMA networks is investigated in this paper. Three cross-layer radio resource management (RRM) algorithms for OFDMA operational scenarios are considered. These algorithms build upon typical network planning practices for OFDMA systems. The first two implement an OFDMA network with opportunistic rate adaptation while the third one aims at a network which guarantees QoS provision through power control on carrier basis. The RRM algorithms are based on typical OFDMA resource allocation targets such as minimization of transmit power, maximization of throughput and interference averaging. Then, the OB concept is combined with the considered RRM algorithms and a comparative performance analysis between the two types of networks (omni and opportunistic beamforming) is performed in terms of throughput, blocking probability and fairness. The paper aims at providing a useful insight into the way the OB technique affects the performance of different OFDMA networks based on large scale simulations. The simulation results suggest that OB is preferred for OFDMA systems with opportunistic rate adaptation rather than power controlled systems which offer QoS provision. According to the presented results, OB provides to OFDMA systems with opportunistic rate adaptation a ??13% throughput gain and ??75% gain in terms of blocking probability. In addition, it is shown that the combination of OB with interference averaging RRM algorithms has a minor beneficial impact only on the system fairness.