BACKGROUND Although many articles on perforating veins have been published, much knowledge about these veins is lacking. OBJECTIVE In this review relevant facts about the clinical importance of perforating veins in venous disease are described. METHODS A literature search on English, French and German articles has been performed using literature databases like Medline, Embase and Cochrane. ...

The hexanucleoside pentaphosphate d(m-'CpGpnrCpGpm-'CpG) has been studied in solution by ultra-violet absorption, circular dichroism and 31p nuclear magnetic resonance under various experimental conditions. In 0.2 M NaClO^ at low temperature, an hexamer duplex is formed which has a B or B-like conformation. As the salt concentration is increased, a transition from a B-form to the Z-fonn occurs ...

Background and Objective: Sexually infections transmitted by bacteria are one of thetherapeutic and social problemsworldwide. The Real-time PCR assay is one of the most sensitive diagnostic and screening methods for these infections. The purpose of this study wassimultaneous detection of Chlamydia trachomatis and Mycoplasma genitaliumusing the TaqMan duplex real-time polymerase chain reaction. ...

In this paper, in addition to some elementary facts about the ultra-groups, which their structure based on the properties of the transversal of a subgroup of a group, we focus on the relation between a group and an ultra-group. It is verified that every group is an ultra-group, but the converse is not true generally. We present the conditions under which, for every normal subultra-group of an u...

We study a multi-cell multi-user MIMO full-duplex network, where each base station (BS) has multiple antennas with full-duplex capability supporting single-antenna users with either full-duplex or half-duplex radios. We characterize the upand downlink ergodic achievable rates for the case of linear precoders and receivers. The rate analysis includes practical constraints such as imperfect selfi...

Impulse radio is an ultrawideband system with attractive features for baseband asynchronous multiple-access, multimedia services, and tactical wireless communications. Implemented with analog components, the continuous-time impulse radio multiple-access model utilizes pulse-position modulation and random time-hopping codes to alleviate multipath effects and suppress multiuser interference. We i...

In this contribution, the direct conversion receiver (DCR) has been revisited and its properties have thoroughly been studied in detail. Contrary to common practice, our main interest is focused on the investigation of DCR performance degradation in conjunction with the processing of ultra-wideband FDM-signals. To this end, all potential DCR error sources have been identified and introduced int...

We consider “virtual” full-duplex relaying by means of half-duplex relays. In this configuration, each relay stage in a multi-hop relaying network is formed by at least two relays, used alternatively in transmit and receive modes, such that while one relay transmits its signal to the next stage, the other relay receives a signal from the previous stage. With such a pipelined scheme, the source ...

in this paper, we establish some new results in ultra bessel sequences and ultra bessel sequences of subspaces. also, we investigate ultra bessel sequences in direct sums of hilbert spaces.specially, we show that {( fi, gi)}∞ i=1 is a an ultra bessel sequencefor hilbert space h ⊕ k if and only if { fi}∞ i=1 and {gi}∞ i=1 are ultrabessel sequences for hilbert spaces h and k, respectively.