Effect of enhancing the Raman gain factor on the linearity of Raman fibre amplifiers

The effect of enhancing the Raman gain factor on the linearity characteristics of Raman fibre amplifiers is analysed. In addition to providing higher Raman gain per unit pump power, a higher value for the Raman gain factor also results in a lower value for the maximum gain, and therefore the maximum output power, available from the amplifier if it is to operate in the linear regime. This has important implications for optimising the design of Raman fibre amplifiers.<>     

Novel fibre optic gyroscope with a configuration combining Sagnac interferometer with fibre ring resonator

A novel fibre optic gyroscope, with a structure making use of the combination of a Sagnac interferometer with an active fibre ring-resonator, is proposed and analysed. The proposed gyroscope can be viewed as a generalised structure of the conventional Sagnac interferometric type fibre optical gyroscope. It has the advantages of both long fibre loop length and multipath interferences. By inserting a fibre amplifier in the loop to provide an optical gain of several dB, the relative maximum sensitivity is enhanced to approximately 30 times more than that of conventional Sagnac interferometric fibre optic gyroscopes.<>     

Primary spinal T-cell rich B-cell lymphoma: a case report

During my nursing career, I remember constantly being aware of patients who needed some emotional help--those who were frightened about a forthcoming operation, those who were shocked and despairing after being given their diagnosis and prognosis, others who were down in the dumps because they couldn't go home as soon as they had hoped. There were also the 'ward clowns' who tried to make everyone laugh with their good humour and little pranks, yet felt no less anxious, worried or depressed than anyone else. Patients seem to fit into categories: the nervous ones, the depressives, the jovial types, the moaners, those who demand attention and those who shun it. I feel sure that every nurse has noticed the different 'types' of people who fill hospital beds-ordinary people who seem to take on a new persona as soon as they get into their pyjamas and become a 'patient'. Somehow, their identity gets folded up and put away in their locker along with their outdoor clothes and other reminders of the outside world.     

Pentoxifylline inhibits hypoxia-induced upregulation of tumor cell tissue factor and vascular endothelial growth factor

The aim of this study was to compare the performance of CT and MRI in the diagnosis of longitudinal stress fracture of the tibia (LSFT). A retrospective study of imaging findings was performed in 15 patients with LSFT. The CT and MR images were compared for detection of fracture line, callus, bone marrow edema, and soft tissues changes. The CT and MRI techniques allowed the detection of the fracture line in 82 and 73 % of cases, respectively. The callus was always visualized with CT or MRI. The MRI technique had a markedly higher sensitivity than CT in the detection of bone marrow edema (73 vs 18 %) and soft tissue lesions (87 vs 9 %). This may cause a misleading aggressive appearance on MRI. Computed tomography remains the best imaging modality for diagnosis of LSFT. However, MRI findings should be known to obviate the performance of CT or bone biopsy.     

Strongyloides stercoralis: identification of antigens in natural human infections from endemic areas of the United States

Using Western-blot analysis, we identified eight immunodominant antigens (apparent molecular weights 96, 86, 75, 56, 41, 32, 28, and 26 kDa) of Strongyloides stercoralis in natural human infections. For this study, 78 individual serum samples were obtained from S. stercoralis-infected patients residing in endemic areas of the United States. Poly A+ RNA was translated in vitro in the rabbit-reticulocyte lysate system. The newly synthesized translation products were immuno-precipitated with S. stercoralis human infection sera. All eight of the identified antigens were detected in the immunoprecipitates. The potential of these antigens as targets for immunodiagnosis is also discussed.     

Time-domain measurement of negative group delay in negative-refractive-index transmission-line metamaterials

We have simulated and constructed a one-dimensional metamaterial composed of a periodically loaded transmission line that exhibits both negative and positive group velocities in a band of effective negative index of refraction. The negative group velocity or, equivalently, the negative group delay, is demonstrated theoretically and experimentally in the time domain using modulated Gaussian pulses. Due to this negative delay, we can show an output pulse peak emerging from the loaded transmission line prior to the input peak entering the line, i.e., the output pulse precedes the input pulse. The fact that this surprising behavior does not violate the requirements of relativistic causality is illustrated with time-domain simulations, which show that discontinuities in the pulse waveforms are traveling at exactly the speed of light in vacuum. The pulse-reshaping mechanism underlying this behavior is also illustrated using time-domain simulations.     

Isolierung der durch ?thylenoxyd-1,214C derivatisierten Inhaltsstoffe aus Kakao und ihre massenspektrometrisch ermittelte Struktur

Zusammenfassung Bei der Auftrennung zahlreicher Fraktionen durch Extraktion und PDC aus dem Äthylenoxyd-1,2-¹⁴C begasten Kakaopulver (Entkeimung) konnten aus dem Wasserextrakt 2 Verbindungen isoliert werden, deren Struktur aufgrund der Massenspektren und IR-Spektren alsN,N-Bis-(Di-Äthoxy-O-hydroxyäthyl)-isoleucyl-alanyl-cystein (MG = 569) undN-(Äthoxy-O-hydroxyäthyl)-Tyrosin gefunden wurde. Die Konzentrationen liegen ungefü:hr bei 20 bzw. 50 mg/kg Kakaopulver.

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Isolation of the derivatives from coca-powder fumigated by ethylene oxide 1,2-¹⁴C and their Structure Suggested on the Basis of I. R. and Mass-Spectrometry

Summary In Coca-powder fumigated with Ethylene Oxide-1,2¹⁴C, several derivatives were isolated by extraction and preparative Thin Layer Chromatography. Of the two compounds isolated from the water-extract, the structures have been suggested asN,N-Bis-(Di-Ethoxy-O-Hydroxy-ethyl)-Isoleucyl-Alanyl-Cysteine (MW = 569) andN-(Ethoxy-O-Hydroxyethyl)-Tyrosine (MW = 269), based on I. R. and Mass Spectrometry. Their approximate concentrations were found to be 20 and 50 mg/kg respectively.

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Wir danken der Deutschen Forschungsgemeinschaft für ihre finanzielle Unterstützung dieser Arbeit.

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Untersuchungen über das Verhalten von Äthylenoxyd bei der Begasung von Lebensmitteln, IX. Mitteilung.

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Zum Teil aus der Dissertation von I. R. Siddiqui, Universität Bonn.     

Group separation of ethylene oxide 1,2-14c fumigated coca-powder derivatives and their distribution of radioactivity (author's transl)]

A procedure based on extraction, column chromatography and precipitation is described for the separation of ethylene oxide-1,2-14C fumigated coca-powder derivatives in 9 different groups. As it was found in wheat [1], the major portion of radioactivity lies in water extract; in coca-powder the major portion of radioactivity is also found in low molecular components.