1,779 research outputs found
Analysis of the volatile components of five Turkish Rhododendron species by headspace solid-phase microextraction and GC-MS (HS-SPME-GC-MS)
Volatile constituents of various solvent extracts (n-hexane, CH2Cl2, H2O) of 15 different
organs (leaves, flowers, fruits) of five Rhododendron species (Ericaceae) growing in Turkey
were trapped with headspace solid-phase microextraction (HS-SPME) technique and analyzed
by GC-MS. A total of 200 compounds were detected and identified from organic extracts,
while the water extracts contained only traces of few volatiles. The CH2Cl2 extract of
the R. luteum flowers was found to exhibit the most diverse composition: 34 compounds
were identified, with benzyl alcohol (16.6%), limonene (14.6%) and p-cymene (8.4%) being
the major compounds. The CH2Cl2-solubles of R. x sochadzeae leaves contained only phenyl
ethyl alcohol. This study indicated appreciable intra-specific variations in volatile compositions
within the genus. Different anatomical parts also showed altered volatile profiles. This
is the first application of HS-SPME-GC-MS on the volatiles of Rhododendron species
Liquid-Phase Chemical Sensing Using Lateral Mode Resonant Cantilevers
Liquid-phase operation of resonant cantilevers vibrating in an out-of-plane flexural mode has to date been limited by the considerable fluid damping and the resulting low quality factors (Q factors). To reduce fluid damping in liquids and to improve the detection limit for liquid-phase sensing applications, resonant cantilever transducers vibrating in their in-plane rather than their out-of-plane flexural resonant mode have been fabricated and shown to have Q factors up to 67 in water (up to 4300 in air). In the present work, resonant cantilevers, thermally excited in an in-plane flexural mode, are investigated and applied as sensors for volatile organic compounds in water. The cantilevers are fabricated using a complementary metal oxide semiconductor (CMOS) compatible fabrication process based on bulk micromachining. The devices were coated with chemically sensitive polymers allowing for analyte sorption into the polymer. Poly(isobutylene) (PIB) and poly(ethylene-co-propylene) (EPCO) were investigated as sensitive layers with seven different analytes screened with PIB and 12 analytes tested with EPCO. Analyte concentrations in the range of 1−100 ppm have been measured in the present experiments, and detection limits in the parts per billion concentration range have been estimated for the polymer-coated cantilevers exposed to volatile organics in water. These results demonstrate significantly improved sensing properties in liquids and indicate the potential of cantilever-type mass-sensitive chemical sensors operating in their in-plane rather than out-of-plane flexural modes
Recapitulating cranial osteogenesis with neural crest cells in 3-D microenvironments
The experimental systems that recapitulate the complexity of native tissues and enable precise control over the microenvironment are becoming essential for the pre-clinical tests of therapeutics and tissue engineering. Here, we described a strategy to develop an in vitro platform to study the developmental biology of craniofacial osteogenesis. In this study, we directly osteo-differentiated cranial neural crest cells (CNCCs) in a 3-D in vitro bioengineered microenvironment. Cells were encapsulated in the gelatin-based photo-crosslinkable hydrogel and cultured up to three weeks. We demonstrated that this platform allows efficient differentiation of p75 positive CNCCs to cells expressing osteogenic markers corresponding to the sequential developmental phases of intramembranous ossification. During the course of culture, we observed a decrease in the expression of early osteogenic marker Runx2, while the other mature osteoblast and osteocyte markers such as Osterix, Osteocalcin, Osteopontin and Bone sialoprotein increased. We analyzed the ossification of the secreted matrix with alkaline phosphatase and quantified the newly secreted hydroxyapatite. The Field Emission Scanning Electron Microscope (FESEM) images of the bioengineered hydrogel constructs revealed the native-like osteocytes, mature osteoblasts, and cranial bone tissue morphologies with canaliculus-like intercellular connections. This platform provides a broadly applicable model system to potentially study diseases involving primarily embryonic craniofacial bone disorders, where direct diagnosis and adequate animal disease models are limited
Glandular trichomes and essential oils of Salvia glutinosa L.
The aerial organs of Salvia glutinosa L. bear indumentum with two types of trichomes: simple and multicellular nonglandular trichomes, and stalked and sessile dense glandular trichomes. Glandular trichomes are extremely long-stalked and dense on the stem and calyx surfaces. However, sessile glands are rare on the stem, calyx and leaf adaxial surfaces and dense on the leaf abaxial surface. Secretion accumulates in a subcuticular space and is released to the outside by cuticle rupture. Water distilled essential oil from dried aerial parts of S. glutinosa was analysed by GC/MS. The main constituent was identified as 1-octadecanol (11.6%)
Drexel University
We present a 3D matching framework based on a many-to-many matching algorithm that works with skeletal representations of 3D volumetric objects. We demonstrate the performance of this approach on a large database of 3D objects containing more than 1000 exemplars. The method is especially suited to matching objects with distinct part structure and is invariant to part articulation. Skeletal matching has an intuitive quality that helps in defining the search and visualizing the results. In particular, the matching algorithm produces a direct correspondence between two skeletons and their parts, which can be used for registration and juxtaposition. 1
Forecasting of Suspended Sediment in Rivers Using Artificial Neural Networks Approach
Suspended sediment estimation is important to the water resources management and water quality problem. In this article, artificial neural networks (ANN), M5tree (M5T) approaches and statistical approaches such as Multiple Linear Regression (MLR), Sediment Rating Curves (SRC) are used for estimation daily suspended sediment concentration from daily temperature of water and streamflow in river. These daily datas were measured at Iowa station in US. These prediction aproaches are compared to each other according to three statistical criteria, namely, mean square errors (MSE), mean absolute relative error (MAE) and correlation coefficient (R). When the results are compared ANN approach have better forecasts suspended sediment than the other estimation methods
Rapid chemical analysis and antiprotozoal effect of the solvent extracts and the essential oil of Artemisia indica
Artemisia indica is used as antipyretic in malarial fevers during malaria outbreaks in India [1]. We selected this plant because reports concerning the presence of artemisinin is contradictory, the content of methoxyflavonoids that potentiate the antimalarial efficacy of artemisinin has remained unstudied and the essential oil of the plant from different regions shows great chemical variations. Solvent extracts [petroleum ether, n-hexane, dichloromethane, acetone, MeOH or EtOH (96, 80 or 60% v/v), and hot water] of A. indica leaves originated from the West Bengal region (India) were assessed by HPLC-DAD and HPLC-MS for the content of artemisinin and the characteristic Artemisia methoxyflavonoids, eupatin, casticin, chrysoplenetin, cirsilineol, chrysosphenol-D and artemetin. None of the extracts contained artemisinin or the methoxyflavonoids chrysosphenol-D and artemetin, while all extracts contained chrysoplenetin. Eupatin, casticin and cirsilineol were found in all extracts except for the p. ether, n-hexane and hot water infusion. The acetone and EtOH extracts contained the highest levels of polymethoxyflavonoids (1.15 – 1.17%), whereas the infusion was devoid of them. The essential oil of the plant was obtained by hydrodistillation and analyzed by GC and GC-MS simultaneously. Of the 92 compounds detected in the oil, camphor (13.0%) and caryophyllene oxide (10.87%) were the major components. All solvent extracts and the volatile oil showed in vitro antimalarial activity (1.8 – 20 µg/mL). Except for the infusion, all extracts were also active against other parasitic protozoa (Trypanosoma b. rhodesiense, T. cruzi, Leishmania donovani). This is the first study investigating both artemisinin and polymethoxyflavonoid content and detailed in vitro antiprotozoal potential of A. indica extracts and the essential oil
Türkiye'de Doğal Olarak Yetişen Ve Aktarlarda Satılan Sumak (Rhus Corıarıa L.) Meyvelerinin Yağ Asidi Kompozisyonlarının Kimyasal Karakterizasyonu Ve Antimikrobiyal Aktivitesi
Objective: The aim of this study was to compare the fatty acid components and antimicrobial properties of R. coriaria L. samples which were sold as powder and grains that show natural distribution in Tunceli and Siirt. Material and Method: After the seeds were weighed and powdered, fixed oils were obtained by using soxhalet apparatus. Obtained fixed oils were analyzed by GC and GC / MS methods after methylation process. In vitro antimicrobial activity studies of the samples were performed using six different Gram negative and Gram positive bacteria and Candida albicans using EUCAST disc diffusion and CLSI microdilution methods. Result and Discussion: The main fatty acid components of all samples were determined as oleic acid (42.2 - 43.3%), linoleic acid (25.2 - 28.5%) and palmitic acid (18.4-221.5%), respectively. In vitro antimicrobial activity of fixed oils, such as Escherichia coli NRRL B-3008, Staphylococcus aureus ATCC 6538, S. epidermidis ATCC 14990, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis NRRL B-A78 A78. Results were compared with standard antimicrobial agents and MIC values> 2.5 - 0.22 mg/ml. The results were found to be significant in terms of antimicrobial efficacy. © 2020 University of Ankara. All rights reserved
- …
