808 research outputs found
Анализ проблем инновационного развития медицины в Украине
Проанализированы проблемы, тормозящие развитие инновационной деятельности в медицине Украины, и внесены предложения по их устранению.Проаналізовано проблеми, які стримують розвиток інноваційної діяльності в медицині України, і внесено пропозиції щодо їх усунення.The paper contains an analysis of barriers for innovation in the Ukrainian medical sector, with propositions for their elimination
Searching for sterile neutrinos in ice
Oscillation interpretation of the results from the LSND, MiniBooNE and some
other experiments requires existence of sterile neutrino with mass eV
and mixing with the active neutrinos . It has
been realized some time ago that existence of such a neutrino affects
significantly the fluxes of atmospheric neutrinos in the TeV range which can be
tested by the IceCube Neutrino Observatory. In view of the first IceCube data
release we have revisited the oscillations of high energy atmospheric neutrinos
in the presence of one sterile neutrino. Properties of the oscillation
probabilities are studied in details for various mixing schemes both
analytically and numerically. The energy spectra and angular distributions of
the events have been computed for the simplest mass, and
mixing schemes and confronted with the IceCube data. An
illustrative statistical analysis of the present data shows that in the
mass mixing case the sterile neutrinos with parameters required by
LSND/MiniBooNE can be excluded at about level. The
mixing scheme, however, can not be ruled out with currently available IceCube
data.Comment: 41 pages, 16 figures. Accepted for publication in JHEP. Minor changes
from the previous versio
A new and sensitive reaction rate method for spectrophotometric determination of trace amounts of thiourea in different water samples based on an induction period
BACKGROUNDAgrilus bigutattus (Fabricius) is a forest pest of increasing importance in the United Kingdom. The larvae damage weakened native oaks and are thought to contribute to premature tree death. Suspected links with acute oak decline (AOD) are not yet confirmed, but AOD-predisposed trees appear to become more susceptible to A. biguttatus attack. Thus, management may be necessary for control of this insect. To explore the possibility of monitoring beetle populations by baited traps, the host tree volatiles regulating A. biguttatus-oak interactions were studied. RESULTSBiologically active volatile organic compounds in dynamic headspace extracts of oak foliage and bark were identified initially by coupled gas chromatography-electroantennography (GC-EAG) and GC-mass spectrometry (GC-MS), and the structures were confirmed by GC coinjection with authentic compounds. Of two synthetic blends of these compounds comprising the active leaf volatiles, the simpler one containing three components evoked strongly positive behavioural responses in four-arm olfactometer tests with virgin females and males, although fresh leaf material was more efficient than the blend. The other blend, comprising a five-component mixture made up of bark volatiles, proved to be as behaviourally active for gravid females as bark tissue. CONCLUSIONSThese initial results on A. biguttatus chemical ecology reveal aspects of the role of attractive tree volatiles in the host-finding of beetles and underpin the development of semiochemically based surveillance strategies for this forest insect. (c) 2015 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry
Effect of chlorhexidine on the shear bond strength of self-etch adhesives to dentin
The aim of this study was to investigate the effect of chlorhexidine on shear bond strength of self-etch adhesives to dentin. The crowns of 60 sound human premolars were horizontally sectioned to expose the coronal dentin. Dentin surfaces were polished with 320 grit silicon carbide papers, and were randomly divided into 4 groups (n = 15). In group 1, two-step self-etch adhesive resin (Clearfil SE Bond) was used. In group 2, the surface was rinsed with chlorhexidine 2% solution prior to Clearfil SE bond application. In groups 3 and 4, the procedure was repeated similar to groups 1 and 2. In this case, onestep self-etch adhesive resin (Clearfil S3 Bond) was used. Then Z100 composite resin was applied. Subsequent to thermocycling, the shear bond strengths were measured. Data were analyzed using oneway ANOVA. In this study, p < 0.05 was considered significant. There were no significant differences between groups (p = 0.321). The use of 2% chlorhexidine had no effect on the shear bond strength of two-step and one-step self-etching adhesive resins. Moreover, there was no significant difference in the shear bond strength values between two-step and one-step self-etching adhesive resins.Key words: Chlorhexidine, shear bond strength, one-step self-etch adhesive resin, two-step self-etch adhesive resin
Growth assessments of Nicotianatabaccumcv.Xanthitransformed with Arabidopsis thalianaP5CS under salt stress
Proline plays important role in osmo-adjusment and prevention of osmotic stress in plants. In order to analyze osmotic stress resistance, germination and growth pattern in vitro and in vivo, the Arabidopsis thalianaδ-1-pyrroline-5-carboxylate synthetase (P5CS) which is the regulatory enzyme of proline biosynthesis, was reverse transcribed, amplified into double stranded cDNA, cloned and transformed into tobacco using Agrobacterium tumefaciens mediated transformation. Seeds of chimeric T0transgenic plants were grown; T1 and the succeeding T2 transgenic plants were obtained. Subsequently, wild type and binary vector transformed control plants along with T2 transgenic lines were exposed to salt concentrations from 0 to 250 mM during germination and growth stages. Results showed a significant difference (P < 0.0001) between T2 and control plants, while the control plants germinated in the presence of salt concentrations up to 50 mM and tolerated 100 mM salt during growth phase. Transgenic T2 lines were able to germinate in 200 mM NaCl and tolerated up to 250 mM salt during growth phase. Assessing proline contents, we observed 7.5 times more proline in T2 transgenic plantsthan control plants in normal condition which increased up to 3.3 folds in stress condition. This osmotic stress resistance was further assessed for T3 generation against drought and salt stresses in vivo. Results indicated osmotic stress resistance of T3 generation as well as stable expression of P5CS along with achievement of homozygous transgenic lines.Key words: δ-1-Pyrroline-5-carboxylate synthetase (P5CS), osmotic stress, transgenic plants, germination, growth phase
Macromixing study for various designs of impellers in a stirred vessel
The effect of the impeller designs and impeller clearance level (C/T) on power consumption, mixing time and air entrainment point in a single liquid phase under turbulent conditions (Re > 104) were investigated. Different impeller designs including conventional and new designs, were used to consider both axial and radial flow impellers. The electric conductivity method, suspended motor system and observation method were employed to determine the mixing time, the power consumption and the air entrainment point, respectively. The reduction in the impeller clearance level form T/3 to T/6 resulted in a decrease in power number values for up-flow pumping impellers while it was increased for down-flow pumping. The same trend was observed for the mixing time results. Moreover, axial flow impellers and specially HE3 are preferable for higher agitation speeds due to the less air entrainment. The results verified that the axial flow impellers and specifically down-flow impellers are more efficient than the radial flow impellers. ANFIS-Fuzzy C–means (ANFIS–FcM) and nonlinear regression were used to develop models to predict the mixing time based on the energy dissipation rate and clearance. The results verified that the model predictions successfully fit the experimental mixing time data
An improved parameter estimation and comparison for soft tissue constitutive models containing an exponential function
Motivated by the well-known result that stiffness of soft tissue is proportional to the stress, many of the constitutive laws for soft tissues contain an exponential function. In this work, we analyze properties of the exponential function and how it affects the estimation and comparison of elastic parameters for soft tissues. In particular, we find that as a consequence of the exponential function there are lines of high covariance in the elastic parameter space. As a result, one can have widely varying mechanical parameters defining the tissue stiffness but similar effective stress–strain responses. Drawing from elementary algebra, we propose simple changes in the norm and the parameter space, which significantly improve the convergence of parameter estimation and robustness in the presence of noise. More importantly, we demonstrate that these changes improve the conditioning of the problem and provide a more robust solution in the case of heterogeneous material by reducing the chances of getting trapped in a local minima. Based upon the new insight, we also propose a transformed parameter space which will allow for rational parameter comparison and avoid misleading conclusions regarding soft tissue mechanics
Non-Contact Measurement of Cardiopulmonary Activity Using Software Defined Radios.
Vital signs are important indicators to evaluate the health status of patients. Channel state information (CSI) can sense the displacement of the chest wall caused by cardiorespiratory activity in a non-contact manner. Due to the influence of clutter, DC components, and respiratory harmonics, it is difficult to detect reliable heartbeat signals. To address this problem, this paper proposes a robust and novel method for simultaneously extracting breath and heartbeat signals using software defined radios (SDR). Specifically, we model and analyze the signal and propose singular value decomposition (SVD)-based clutter suppression method to enhance the vital sign signals. The DC is estimated and compensated by the circle fitting method. Then, the heartbeat signal and respiratory signal are obtained by the modified variational modal decomposition (VMD). The experimental results demonstrate that the proposed method can accurately separate the respiratory signal and the heartbeat signal from the filtered signal. The Bland-Altman analysis shows that the proposed system is in good agreement with the medical sensors. In addition, the proposed system can accurately measure the heart rate variability (HRV) within 0.5m. In summary, our system can be used as a preferred contactless alternative to traditional contact medical sensors, which can provide advanced patient-centered healthcare solutions
Cooperative In-Vivo Nano-Network Communication at Terahertz Frequencies
Nano devices have great potential to play a vital role in future medical diagnostics and treatment technologies because of its non-invasive nature and ability to reach delicate body sites easily as compared to conventional devices. In this paper, a novel concept of cooperative communication for in-vivo nano network is presented to enhance the communication among these devices. The effect on the system outage probability performance is conducted for various parameters including relay placement, number of relays, transmit power, bandwidth and carrier frequency. Results show approximately a 10-fold increase in the system outage performance whenever an additional relay is included in the cooperative network, hence shows a great potential of using cooperative communication to enhance the performance of nano-network at terahertz frequencies
Synthesis of 3-[4-(2-furoyl)-1-piperazinyl]-N- (substituted)propanamides as promising antibacterial agents with mild cytotoxicity
Purpose: To evaluate the antibacterial activity and cytotoxicity of a series of molecules with amalgamation of furoyl, piperazine and amide moieties.Methods: New derivatives, namely 3-[4-(2-furoyl)-1-piperazinyl]-N-(substituted) propanamides, were synthesized and evaluated for their antibacterial activity and toxicity to mammalian cells. The synthesis was initiated by treating different aryl/aralkyl amines (1a-u) with 3-bromopropionyl chloride (2) to obtain the solid electrophiles 3a-u, which were collected by filtration. Thereafter, the different N-aryl/aralkyl-3- bromopropionamides (3a-u) and 2-furoyl-1-piperazine (4) at equimolar ratios were allowed to react in acetonitrile and in the presence of a base, K2CO3, to form the target compounds, 5a-u. Structural elucidation was carried out using EI-MS (electron impact mass spectrometry), IR (infrared) and 1H-NMR (proton nuclear magnetic resonance). The antibacterial activity of the synthesized compounds was evaluated against various bacterial strains. Furthermore, hemolysis was determined to assess cytotoxicity using bovine red blood cells.Results: Molecules 5g, 5a, 5p, 5g and 5i were found to be potent agents against S. aureus, S. typhi, P. aeruginosa, E. coli and B. subtilis with respective minimum inhibitory concentration (MIC) values of 8.34 ± 0.55, 8.37 ± 0.12, 8.65 ± 0.57, 8.97 ± 0.12 and 9.24 ± 0.50 μM, compared to 7.80 ± 0.19, 7.45 ± 0.58, 7.14 ± 0.58, 7.16 ± 0.58 and 7.29 ± 0.90 μM for the reference standard, ciprofloxacin. The most active compounds, 5a, 5g, 5i and 5p, showed a hemolysis of 15.48, 8.03, 5.52 and 4.35 %, respectively.Conclusion: The synthesized compounds exhibit good antibacterial activity. The hemolysis data indicate that these compounds have a low toxicity level. However, in vivo studies are required to ascertain their potentials as new drug candidates.Keywords: 4-(2-Furoyl)-1-piperazine, 1H-NMR, EI-MS, Antimicrobial activity, Hemolytic activit
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