60 research outputs found
The aqueous trimethylamine mediated Baylis-Hillman reaction
Aqueous trimethylamine mediated Baylis-Hillman coupling of alkyl acrylates with aldehydes is described
Optimization of the Culture Medium Composition to Improve the Production of Hyoscyamine in Elicited Datura stramonium L. Hairy Roots Using the Response Surface Methodology (RSM)
Traditionally, optimization in biological analyses has been carried out by monitoring the influence of one factor at a time; this technique is called one-variable-at-a-time. The disadvantage of this technique is that it does not include any interactive effects among the variables studied and requires a large number of experiments. Therefore, in recent years, the Response Surface Methodology (RSM) has become the most popular optimization method. It is an effective mathematical and statistical technique which has been widely used in optimization studies with minimal experimental trials where interactive factors may be involved. This present study follows on from our previous work, where RSM was used to optimize the B5 medium composition in [NO3−], [Ca2+] and sucrose to attain the best production of hyoscyamine (HS) from the hairy roots (HRs) of Datura stramonium elicited by Jasmonic Acid (JA). The present paper focuses on the use of the RSM in biological studies, such as plant material, to establish a predictive model with the planning of experiments, analysis of the model, diagnostics and adjustment for the accuracy of the model. With the RSM, only 20 experiments were necessary to determine optimal concentrations. The model could be employed to carry out interpolations and predict the response to elicitation. Applying this model, the optimization of the HS level was 212.7% for the elicited HRs of Datura stramonium, cultured in B5-OP medium (optimized), in comparison with elicited HRs cultured in B5 medium (control). The optimal concentrations, under experimental conditions, were determined to be: 79.1 mM [NO3−], 11.4 mM [Ca2+] and 42.9 mg/L of sucrose
Symptomatic hypopituitarism revealing primary suprasellar lymphoma
<p>Abstract</p> <p>Background</p> <p>The most common cause of hypopituitarism is pituitary adenoma. However, in the case of suprasellar masses different etiologies are possible. We report an unusual case of primary suprasellar lymphoma presented with hypopituitarism.</p> <p>Case presentation</p> <p>A 26 year old woman presented with amenorrhea, galactorrhea and neurological disorders. Also, the laboratory work-up revealed partial hypopituitarism. The magnetic resonance imaging of the head showed a suprasellar mass. A presumptive diagnosis of granulomatous processes was made and the patient was given steroid therapy. Repeated brain MRI detected new lesions in the brain with regression of the suprasellar mass. Stereotactic biopsy of the paraventricular lesion revealed the diagnosis of B-cell lymphoma.</p> <p>Conclusion</p> <p>This case presentation reports a rare cause of hypopituitarism. Primary suprasellar lymphoma is extremely rare and represented a real diagnostic challenge. Besides, suprasellar masses are varied in aetiology and can present diagnostic problems for a radiologist. Also, because of the increased incidence of PCNSL, lymphoma must be kept in mind in the differential diagnosis of lesions in the suprasellar region.</p
1-Benzopyran-4(4H)-ones as novel activated alkenes in the Baylis-Hillman reaction: a simple and facile synthesis of indolizine-fused-chromones
1-Benzopyran-4(4H)-one derivatives have been successfully employed as novel activated alkenes in the Baylis-Hillman coupling with heteroaromatic-aldehydes, nitrobenzaldehydes and isatin-derivatives and the corresponding adducts, derived from pyridine-2-carboxaldehyde, have been transformed into a novel indolizine-fused-chromone framework
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Not AvailabletTwelve isolates of Trichoderma spp. isolated from tobacco rhizosphere were evaluated fortheir ability to produce chitinase and -1,3-glucanase extracellular hydrolytic enzymes. Iso-lates ThJt1 and TvHt2, out of 12 isolates, produced maximum activities of chitinase and -1,3-glucanase, respectively. In vitro production of chitinase and -1,3-glucanase by iso-lates ThJt1 and TvHt2 was tested under different cultural conditions. The enzyme activitieswere significantly influenced by acidic pH and the optimum temperature was 30◦C. Thechitin and cell walls of Sclerotium rolfsii, as carbon sources, supported the maximum andsignificantly higher chitinase activity by both isolates. The chitinase activity of isolate ThJt1was suppressed significantly by fructose (80.28%), followed by glucose (77.42%), whereasthe -1,3-glucanase activity of ThJt1 and both enzymes of isolate TvHt2 were significantlysuppressed by fructose, followed by sucrose. Ammonium nitrate as nitrogen source sup-ported the maximum activity of chitinase in both isolates, whereas urea was a poor nitrogensource. Production of both enzymes by the isolates was significantly influenced by the cul-tural conditions. Thus, the isolates ThJt1 and TvHt2 showed higher levels of chitinase and -1,3-glucanase activities and were capable of hydrolyzing the mycelium of S. rolfsii infect-ing tobacco. These organisms can be used therefore for assessment of their synergism inbiomass production and biocontrol efficacy and for their field biocontrol ability against S.rolfsii and Pythium aphanidermatum infecting tobacco.Not Availabl
A novel Baylis-Hillman protocol for the synthesis of functionalized fused furans
Titanium tetrachloride mediated Baylis-Hillman reaction of aryl 1,2-diones with α,β-unsaturated ketones leads to the formation of an interesting class of functionalized fused furans
(2S)-2-Anilinomethylpyrrolidine: an efficient in situ recyclable chiral catalytic source for the borane-mediated asymmetric reduction of prochiral ketones in refluxing toluene
(2S)-2-Anilinomethylpyrrolidine was successfully utilized as a chiral catalytic source in the borane-mediated asymmetric reduction of prochiral ketones in refluxing toluene to provide the corresponding secondary alcohols with enantiomeric excesses up to 91%. The potential of (2S)-2-anilinomethylpyrrolidine as an in situ recyclable chiral catalytic source in the borane-mediated chiral reduction processes has also been demonstrated
Phase dependent photocatalytic activity of Ag loaded TiO2 films under sun light
Well-crystallized anatase and mixed (anatase-rutile) phase TiO2 thin films were deposited by DC magnetron sputtering technique at various DC powers in the range of 80-140 W. Pure anatase phase was observed in the TiO2 films deposited at low power of 80 W. Films deposited at 120 W were composed of both anatase and rutile phases. At higher power of 140 W, the films are rutile dominated and the rutile percentage increased from 0 to 82% with increase of DC power. The same results of phase change were confirmed by Raman studies. The surface morphology of the TiO2 films showed that the density of the films increased with increase of sputter power. The optical band gap of the films varied from 3.35 to 3.14 eV with increase of DC power. The photocatalytic activity of the TiO2 films increased with increasing DC power up to 120 W and after that it decreases. We found that the TiO2 films deposited at 120 W with 48% of rutile phase, exhibited high photocatalytic activity (43% of degradation) under UV light compared with other TiO2 films. After loading the optimized Ag nanoparticles on the mixed phase TiO2 films, the photocatalytic activity shifted from UV to visible region with enhancement of photocatalytic activity (55% of degradation). (C) 2015 Elsevier B.V. All rights reserved
Electrical and structural properties of zirconia thin films prepared by reactive magnetron sputtering
Thin films of ZrO2 were prepared by reactive magnetron sputtering. Annealing of the films exhibited a drastic change in the properties due to improved crystallinity and packing density. The root mean square roughness of the sample observed from atomic force microscope is about 5.75 nm which is comparable to the average grain size of the thin film which is about 6 nm obtained from X-ray diffraction. The film annealed at 873 K exhibits an optical band gap of around 4.83 eV and shows +4 oxidation state of zirconium indicating fully oxidized zirconium, whereas higher annealing temperatures lead to oxygen deficiency in the films and this is reflected in their properties. A discontinuity in the imaginary part of the AC conductivity was observed in the frequency range of tens of thousands of Hz, where as, the real part does not show such behavior
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