Search results for "Tipa"

Structural and Functional Analysis of the Antiparallel Strands in the Lumenal Loop of the Major Light-harvesting Chlorophyll a/b Complex of Photosyst…

2007

The light-harvesting chlorophyll a/b-binding protein of photosystem II (LHCIIb) fulfills multiple functions, such as light harvesting and energy dissipation under different illuminations. The crystal structure of LHCIIb at the near atomic resolution reveals an antiparallel strands structure in the lumenal loop between the transmembrane helices B/C. To study the structural and functional significances of this structure, three amino acids (Val-119, His-120, and Ser-123) in this region have been exchanged to Phe, Leu, and Gly, respectively, and the influence of the mutagenesis on the structure and function of LHCIIb has been investigated. The results are as follows. 1) Circular dichroism spect…

Solitary Rectal Ulcer

1979

Solitary ulcers of the rectum may be traumatic in origin and caused by thermometers, occasionally by digital removal of a fecal impaction, or by deviate sexual behavior. Solitary rectal ulcers may also be a manifestation of Crohn’s disease. Very rarely, ectopic gastric mucosa is their cause. For the vast majority of solitary rectal ulcers, the explanation remains unknown. Occasionally, the ulcers are accompanied by localized inflammation of the mucosa within the distal segment of the rectum with edema, erythema, and circumscribed whitish flecks in a thickened bowel wall covered by excessive secretions. The changes are found predominantly in the ventral portion of the rectum, and in contrast…

Fistulae (Rectovaginal, Rectovesical)

1979

The clinical manifestations of a fistula — stool from the vagina, air from the urethra — are often difficult to recognize because the fistulous opening is hidden by the edematous and swollen mucosa. Larger defects occur particularly after radiation therapy and with Crohn’s disease.

Optimized Multipactor-Resistant Wedge-Shaped Waveguide Bandpass Filters

2013

[EN] Wedge-shaped waveguides present a certain advantage with respect to rectangular waveguides regarding their resistance to multipactor discharges. In this paper, the optimal configuration for the wedge geometry is investigated based on theoretical results, on a precise multipactor prediction tool, and on previous experience. In addition, design rules are presented, which allow us to achieve for wedge-shaped filters electrical performances comparable to the ones of rectangular waveguide filters, while at the same time improving the multipactor-free power range. As a proof of concept, two three-pole bandpass filters with equivalent electrical characteristic of 150-MHz bandwidth, centered a…

Cladosporinone, a new viriditoxin derivative from the hypersaline lake derived fungus Cladosporium cladosporioides

2015

A new cytotoxic viriditoxin derivative, cladosporinone (1), along with the known viriditoxin (2) and two viriditoxin derivatives (3 and 4) were obtained from the fungus C ladosporium cladosporioides isolated from the sediment of a hypersaline lake in Egypt. The structure of the new compound (1) was determined by 1D and 2D NMR measurements as well as by high-resolution ESIMS and electronic circular dichroism spectroscopy. All isolated compounds were studied for their cytotoxicity against the murine lymphoma cell line L5187Y and for their antibiotic activity against several pathogenic bacteria. Viriditoxin (2) was the most active compound in both bioassays. Compound 1 also exhibited strong cy…

USO DEI PARAMETRI POSIZIONALI E DELL’ANALISI CITOMETRICA MULTIPARAMETRICA PER IDENTIFICARE I CASI DI LEUCEMIA LINFATICA CRONICA

2013

Spectrogram Analysis of Multipath Fading Channels under Variations of the Mobile Speed

2016

When modelling, analysing, and simulating mobile radio channels, it is generally assumed that the speed of the mobile station (MS) is constant. In practice, however, the mobile speed varies with time. Mobile speed variations result in nonwide- sense stationary multipath fading channels, which can be modelled by a sum-of-chirps (SOCh) processes. In this paper, we analyse the local Doppler power spectral density (PSD) of SOCh processes by using the concept of the spectrogram. The spectrogram provides an estimate of the local Doppler PSD and gives insight into how the Doppler PSD changes over time if the MS increases or decreases its speed. A closed-form solution is presented for the spectrogr…

A method to estimate the path gains and propagation delays of underwater acoustic channels using the arrival phase information of the multipath compo…

2017

Abstract We propose a method for the estimation of the channel parameters of underwater acoustic channels (UACs) by using a pseudo-noise (PN) sequence. For the channel sounding, the PN sequence is coherently modulated on a carrier frequency by using a binary phase-shift keying (BPSK) modulation scheme. For the demodulation, the arrival phases of the received BPSK signals must be known at the receiver. In practice, however, the arrival phases of the received signal are unknown. We propose to demodulate the received BPSK signal by using an hypothetical arrival phase, which will be increased from 0 to 2 π . The demodulated signal obtained by using the hypothetical arrival phase is then correla…

Doppler Power Characteristics Obtained from Calibrated Channel State Information for Human Activity Recognition

2020

This paper demonstrates the time-variant (TV) Doppler power characteristics of human activities using measured channel state information (CSI). We model the measured CSI as a complex channel transfer function corresponding to a 3D non-stationary multipath fading channel consisting of a fixed transmitter, a fixed receiver, fixed scatterers representing fixed objects, and a cluster of moving scatterers representing a moving person performing some human activities. We demonstrate the relationship between the TV Doppler frequency caused by each moving scatterer and the rate of change of its corresponding TV propagation delay. Furthermore, we express the TV mean Doppler shift in terms of the pat…

Modelling and Analysis of Non-Stationary Multipath Fading Channels with Time-Variant Angles of Arrival

2017

In mobile radio channel modelling, it is generally assumed that the angles of arrival (AOAs) are independent of time. This assumption does in general not agree with real-world channels in which the AOAs vary with the position of a moving receiver. In this paper, we first present a mathematical model for the time-variant AOAs. This model serves as the basis for the development of two non-stationary multipath fading channels models. The statistical properties of both channel models are analysed with emphasis on the time-dependent autocorrelation function (ACF), time-dependent mean Doppler shift, time-dependent Doppler spread, and the Wigner-Ville spectrum. It is shown that these characteristi…