2,490 research outputs found
Preparation of heterocyclic block copolymer from perfluoroalkylene oxide alpha, omega-diamidoximes
Diamidoxime monomers are intermolecularly and thermally condensed to form a heat and chemical resistant polymer containing 1,2,4-oxadiazole linkages with identical bivalent organic radicals or any combination of bivalent organic radicals selected from the group consisting of -(CX(sub 2))p-, wherein P ranges from 2 to 8 when X is fluorine and 2 to 18 when X is hydrogen, chlorine, nitro or aryl; arylene; and an oligometric or polymeric radical prepared by reacting a dicarboxylic acid halide with a fluorinated epoxide and having the formula: (CFY(OCF(sub 2)CFY)sub m)O(CX(sub 2))(sub p)O(CFYCF(sub 2)O)(sub n)CFY wherein Y is flourine or tryifluoromethyl, X is nitro, aryl, hydrogen, chlorine or fluorine, preferably the latter, p ranges from 1 to 18 and m+n ranges from 2 to 7
Adnexal Torsion in Pediatric Age: Does Bolli's Score Work? Report of Two Cases
Adnexal torsion is a surgical emergency requiring early diagnosis in order to avoid demolitive surgery. Adnexal torsion's diagnosis could be very difficult in pediatric patients because children cannot explain symptoms accurately. Furthermore reproductive organs lie high in abdomen, causing unclear examinations findings. For reducing diagnostic mistakes or delay clinical and hematological criteria could be useful. No radiological criteria (CT or MRI) should be taken in count because of the costs and the required time. By combining clinical presentation in patients with OT three useful diagnostic variables have been identified: age, duration of pain, vomiting. Presence of vomiting, short duration of abdominal pain and high CRP levels have great predictive value for the diagnosis of adnexal torsion. In those patients an exploratory laparoscopy should be performed without any doubt and/or delay. These data may aid physicians in the evaluation of abdominal pain in premenarchal girls
Metastatic tumors to the stomach: clinical and endoscopic features.
AIM: To evaluate the clinical and endoscopic patterns in a large series of patients with metastatic tumors in the stomach. METHODS: A total of 64 patients with gastric metastases from solid malignant tumors were retrospectively examined between 1990 and 2005. The clinicopathological findings were reviewed along with tumor characteristics such as endoscopic pattern, location, size and origin of the primary sites. RESULTS: Common indications for endoscopy were anemia, bleeding and epigastric pain. Metastases presented as solitary (62.5%) or multiple (37.5%) tumors were mainly located in the middle or upper third of stomach. The main primary metastatic tumors were from breast and lung cancer and malignant melanoma. CONCLUSION: As the prognosis of cancer patients has been improving gradually, gastrointestinal (GI) metastases will be encountered more often. Endoscopic examinations should be conducted carefully in patients with malignancies, and endoscopic biopsies and information on the patient's clinical history are useful for correct diagnosis of gastric metastases
Shape-changing Collisions of Coupled Bright Solitons in Birefringent Optical Fibers
Wecritically review the recent progress in understanding soliton propagation
in birefringent optical fibers.By constructing the most general bright
two-soliton solution of the integrable coupled nonlinear Schroedinger equation
(Manakov model) we point out that solitons in birefringent fibers can in
general change their shape after interaction due to a change in the intensity
distribution among the modes even though the total energy is conserved.
However, the standard shape-preserving collision (elastic collision) property
of the (1+1)-dimensional solitons is recovered when restrictions are imposed on
some of the soliton parameters. As a consequence the following further
properties can be deduced using this shape-changing collision. (i) The exciting
possibility of switching of solitons between orthogonally polarized modes of
the birefringent fiber exists. (ii) When additional effects due to periodic
rotation of birefringence axes are considered, the shape changing collision can
be used as a switch to suppress or to enhance the periodic intensity exchange
between the orthogonally polarized modes. (iii) For ultra short optical soliton
pulse propagation in non-Kerr media, from the governing equation an integrable
system of coupled nonlinear Schroedinger equation with cubic-quintic terms is
identified. It admits a nonlocal Poisson bracket structure. (iv) If we take the
higher-order terms in the coupled nonlinear Schroedinger equation into account
then their effect on the shape-changing collision of solitons, during optical
pulse propagation, can be studied by using a direct perturbational approach.Comment: 14 pages, ROMP31, 4 EPS figure
Noise-induced perturbations of dispersion-managed solitons
We study noise-induced perturbations of dispersion-managed solitons by
developing soliton perturbation theory for the dispersion-managed nonlinear
Schroedinger (DMNLS) equation, which governs the long-term behavior of optical
fiber transmission systems and certain kinds of femtosecond lasers. We show
that the eigenmodes and generalized eigenmodes of the linearized DMNLS equation
around traveling-wave solutions can be generated from the invariances of the
DMNLS equations, we quantify the perturbation-induced parameter changes of the
solution in terms of the eigenmodes and the adjoint eigenmodes, and we obtain
evolution equations for the solution parameters. We then apply these results to
guide importance-sampled Monte-Carlo simulations and reconstruct the
probability density functions of the solution parameters under the effect of
noise.Comment: 12 pages, 6 figure
The side chain of glutamine 13 is the acyl-donor amino acid modified by type 2 transglutaminase in subunit T of the native rabbit skeletal muscle troponin complex.
Subunit T of the native muscle troponin complex is a recognised substrate of transglutaminase both in vitro and in situ with formation of isopeptide bonds. Using a proteomic approach, we have now determined the precise site of in vitro labelling of the protein. A preparation of troponin purified from ether powder from mixed rabbit skeletal muscles was employed as transglutaminase substrate. The only isoform TnT2F present in our preparation was recognised as acyl-substrate by human type 2 transglutaminase which specifically modified glutamine 13 in the N-terminal region. During the reaction, the troponin protein complex was polymerized. Results are discussed in relation to the structure of the troponin T subunit, in the light of the role of troponins in skeletal and cardiac muscle diseases, and to the rules governing glutamine side chain selection by tissue transglutaminase
Deterministic Raman crosstalk effects in amplified wavelength division multiplexing transmission
We study the deterministic effects of Raman-induced crosstalk in amplified
wavelength division multiplexing (WDM) optical fiber transmission lines. We
show that the dynamics of pulse amplitudes in an N-channel transmission system
is described by an N-dimensional predator-prey model. We find the equilibrium
states with non-zero amplitudes and prove their stability by obtaining the
Lyapunov function. The stability is independent of the exact details of the
approximation for the Raman gain curve. Furthermore, we investigate the impact
of cross phase modulation and Raman self and cross frequency shifts on the
dynamics and establish the stability of the equilibrium state with respect to
these perturbations. Our results provide a quantitative explanation for the
robustness of differential-phase-shift-keyed WDM transmission against Raman
crosstalk effects.Comment: 34 pages and 12 figures. Revised paper. Submitted to Optics
Communication
From wellness to medical diagnostic apps: the Parkinson's Disease case
This paper presents the design and development of the CloudUPDRS app and supporting system developed as a Class I medical device to assess the severity of motor symptoms for Parkinson’s Disease. We report on lessons learnt towards meeting fidelity and regulatory requirements; effective procedures employed to structure user context and ensure data quality; a robust service provision architecture; a dependable analytics toolkit; and provisions to meet mobility and social needs of people with Parkinson’s
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