Clonal expansion of hypermutated measles virus in a SSPE brain

Nucleotide sequence analysis was carried out to study genes encoding the matrix (M) protein of measles virus (MV) from several regions of the brain of a case of subacute sclerosing panencephalitis. This analysis revealed the presence of MV with "wild-type" sequences as well as variants which had undergone at least five biased hypermutation events (U to C and A to G in the positive strand sequences). Despite the presence of MV variants with genes encoding the intact matrix protein open reading frame, M protein could not be detected in any of the brain regions. The distribution of virus variants was studied by cDNA cloning and sequence analysis and by in situ hybridization. The hypermutated viruses appeared to expand clonally throughout the brain of patient B.     

On Trellis Shaping for PAR Reduction in OFDM Systems

The application of trellis shaping was proposed to reduce the peak-to-average power ratio (PAR) of orthogonal frequency division multiplexing (OFDM) signals. In this letter, we review the trellis-shaping schemes presented in the literature, and we introduce modifications such as a new decoding metric and the use of sequential decoding. We conduct comprehensive complexity and performance comparisons for the different schemes, and one interesting result of this work is that, in terms of PAR-reduction capability, trellis shaping with time-domain metrics is generally superior to trellis shaping with frequency-domain metrics. Furthermore, the proposed modifications enable trellis shaping for PAR reduction with a flexible performance-complexity tradeoff.     

DF-DD for channels with phase noise

In this letter, we design decision-feedback differential detection (DF-DD) schemes for channels with phase noise. If the DF-DD feedback filter is properly optimized, a performance similar to that of a more complex scheme, recently reported by Chiavaccini and Vitetta, based on expectation maximization, can be achieved. However, it is also shown that an error floor is unavoidable for channels with phase noise. If a constraint is introduced, the DF-DD receiver can be made robust against unknown frequency offsets.     

Adenocarcinoma and adenosis of the vagina. On the histogenesis, diagnosis and therapy of a rare genital neoplasms

In the United States, vaginal adenosis and clear-cell carcinoma of the vagina were frequently observed in young women, who had been exposed to the synthetic estrogen diethyl-stilbestrol (DES) during their embryonic development. In Germany, obviously, no such exposure occurred. Clearly, such diseases also develop without the context of intrauterine exposure to certain substances. Our own case of such a partly exophytic, partly endophytic adeno-carcinoma of the vagina with multifocal vaginal adenosis, demonstrates the histogenesis, symptoms, diagnostic procedures and therapy of this rare disease. Since young women during their reproductive years are mostly affected, the possibility of fertility-conserving surgery is discussed despite the current practice of radical cancer surgery (with and without radiation). In the 25-year-old patient, we conducted a colpectomy whilst leaving the uterus and ovaries, and replaced the vaginal defect by a sigmoid transplant anastomosed to the cervix. The patient has regular menstrual cycles, should, however, not become pregnant for 1 to 2 years for oncological reasons.     

Modulation diversity for frequency-selective fading channels

In this article, modulation diversity (MD) for frequency-selective fading channels is proposed. The achievable performance with MD is analyzed and a simple design criterion for MD codes for Rayleigh-fading channels is deduced from an upper bound on the pairwise error probability (PEP) for single-symbol transmission. This design rule is similar to the well-known design rule for MD codes for flat fading and does not depend on the power-delay profile of the fading channel. Several examples for MD codes with prescribed properties are given and compared. Besides the computationally costly optimum receiver, efficient low-complexity linear equalization (LE) and decision-feedback equalization (DFE) schemes for MD codes are also introduced. Simulations for the widely accepted COST fading models show that performance gains of several decibels can be achieved by MD combined with LE or DFE at bit-error rates (BERs) of practical interest. In addition, MD also enables the suppression of cochannel interference.     

The Benefits of Facebook "Friends:" Social Capital and College Students' Use of Online Social Network Sites

This study examines the relationship between use of Facebook, a popular online social network site, and the formation and maintenance of social capital. In addition to assessing bonding and bridging social capital, we explore a dimension of social capital that assesses one's ability to stay connected with members of a previously inhabited community, which we call maintained social capital. Regression analyses conducted on results from a survey of undergraduate students (N = 286) suggest a strong association between use of Facebook and the three types of social capital, with the strongest relationship being to bridging social capital. In addition, Facebook usage was found to interact with measures of psychological well-being, suggesting that it might provide greater benefits for users experiencing low self-esteem and low life satisfaction.     

In situ and minimally invasive breast cancer: morphologic and kinetic features on contrast-enhanced MR imaging

PURPOSE: This retrospective study was undertaken to investigate the morphologic and dynamic features of in situ and minimally invasive breast cancer on contrast-enhanced (c.-e.) MR imaging and to examine possible associations to pathology features. MATERIAL AND METHODS: A total of 71 patients underwent MR imaging. T1-weighted FLASH-3D images were obtained before and after intravenous administration of Gd-DTPA. Histopathologic analysis of 78 lesions revealed ductal carcinoma in situ (DCIS) n = 50 and DCIS with microinvasion n = 28. MR features were correlated with histopathologic findings. RESULTS: Enhancement in DCIS was focal (73%), diffuse (10%) or ductal (17%). No enhancement occurred in two cases (4%). In 65% enhancement speed was classified as delayed. There was a tendency toward a more ill-defined (83 vs. 43%) enhancement pattern in high grade DCIS and a more ductal (29 vs. 12%) and faster (50 vs. 29%) enhancement in comedo type DCIS. However, significant differences in the enhancement behaviour could neither be demonstrated between high grade and non high grade DCIS nor between comedo and non comedo type DCIS. No significant differences were noted between pure and microinvasive DCIS. CONCLUSION: In this retrospective analysis the majority (96%) of DCIS lesions show contrast enhancement. However, in only about 50% of DCIS the criteria of a so-called 'typical' enhancement behaviour was fulfilled, that means strong, early, focal ill-circumscribed or ductal. Enhancement that follows a duct is often associated with malignancy, however this feature was only present in 17% of the cases. c.-e. MR imaging allowed the detection of 25 additional foci of DCIS. Therefore malignant in situ lesions can be present with atypical enhancement, and should be taken into consideration in high-risk patients in particular.     

Comparison of MOE and blind LMS

In this letter, we provide a rigorous analytical comparison of two blind adaptive algorithms for adjustment of the minimum mean-squared error (MMSE) filter for multiple access interference (MAI) suppression for direct-sequence code-division multiple access (DS-CDMA). In particular, we compare the popular minimum-output-energy (MOE) algorithm and the blind least-mean-square algorithm (BLMS) in terms of complexity, transient behavior, convergence, stability, and steady-state performance. We show analytically that the MOE algorithm enjoys a faster speed of convergence and has a superior steady-state performance, while the BLMS algorithm is computationally less complex.     

Der Durchschlagmechanismus positiver,langer Funken in atmosphärischer Luft bei Stoßspannung

Ohne ZusammenfassungMit 19 Textabbildungen