1,843 research outputs found
I-limit superior and limit inferior
In this paper we extend concepts of statistical limit superior and
inferior (as introduced by Fridy and Orhan) to limit superior and inferior and give some analogue of properties of statistical limit superior and inferior for a sequence of real numbers. Also we extend the concept of the statistical core to core for a complex number sequence and get necessary conditions for a summability
matrix to yield whenever is a bounded complex number
sequence
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
Numerical Investigation of Dam-Break Flow over a Bottom Obstacle Using Eulerian Finite Element Method
Dam-break flows can cause major destructions in case settlements located atthe downstream area. Since many people live in the settlements, investigations regarding the dam-break flow have great importance.Dam break flow characteristics can become variousbased on different downstream conditions. In this study, an investigation was made relating tothe dam break flow in a channel with symmetrical triangular-shaped bottom obstacle using Finite Element Method (FEM) formulation. Numerical results of the present study were compared with experimental results. It was concluded that numerical and experimental results are in good agreement
Statistical Modeling of Single Target Cell Encapsulation
High throughput drop-on-demand systems for separation and encapsulation of individual target cells from heterogeneous mixtures of multiple cell types is an emerging method in biotechnology that has broad applications in tissue engineering and regenerative medicine, genomics, and cryobiology. However, cell encapsulation in droplets is a random process that is hard to control. Statistical models can provide an understanding of the underlying processes and estimation of the relevant parameters, and enable reliable and repeatable control over the encapsulation of cells in droplets during the isolation process with high confidence level. We have modeled and experimentally verified a microdroplet-based cell encapsulation process for various combinations of cell loading and target cell concentrations. Here, we explain theoretically and validate experimentally a model to isolate and pattern single target cells from heterogeneous mixtures without using complex peripheral systems.Wallace H. Coulter Foundation (Young Investigator in Bioengineering Award)National Institutes of Health (U.S.) (Grant R01AI081534)National Institutes of Health (U.S.) (Grant R21AI087107
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
Portable Microfluidic Integrated Plasmonic Platform for Pathogen Detection
Timely detection of infectious agents is critical in early diagnosis and treatment of infectious diseases. Conventional pathogen detection methods, such as enzyme linked immunosorbent assay (ELISA), culturing or polymerase chain reaction (PCR) require long assay times, and complex and expensive instruments, which are not adaptable to point-of-care (POC) needs at resource-constrained as well as primary care settings. Therefore, there is an unmet need to develop simple, rapid, and accurate methods for detection of pathogens at the POC. Here, we present a portable, multiplex, inexpensive microfluidic-integrated surface plasmon resonance (SPR) platform that detects and quantifies bacteria, i.e., Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) rapidly. The platform presented reliable capture and detection of E. coli at concentrations ranging from ∼105 to 3.2 × 107 CFUs/mL in phosphate buffered saline (PBS) and peritoneal dialysis (PD) fluid. The multiplexing and specificity capability of the platform was also tested with S. aureus samples. The presented platform technology could potentially be applicable to capture and detect other pathogens at the POC and primary care settings. © 2015, Nature Publishing Group. All rights reserved
Antiprotozoal Activity of Turkish Origanum onites Essential Oil and Its Components
Essential oil of Origanum species is well known for antimicrobial activity, but only a few have been evaluated in narrow spectrum antiprotozoal assays. Herein, we assessed the antiprotozoal potential of Turkish Origanum onites L. oil and its major constituents against a panel of parasitic protozoa. The essential oil was obtained by hydrodistillation from the dried herbal parts of O. onites and analyzed by Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography coupled with Mass Spectrometry (GC-MS). The in vitro activity of the oil and its major components were evaluated against Trypanosoma brucei rhodesiense, T. cruzi, Leishmania donovani, and Plasmodium falciparum. The main component of the oil was identified as carvacrol (70.6%), followed by linalool (9.7%), p-cymene (7%), γ-terpinene (2.1%), and thymol (1.8%). The oil showed significant in vitro activity against T. b. rhodesiense (IC50 180 ng/mL), and moderate antileishmanial and antiplasmodial effects, without toxicity to mammalian cells. Carvacrol, thymol, and 10 additional abundant oil constituents were tested against the same panel; carvacrol and thymol retained the oil's in vitro antiparasitic potency. In the T. b. brucei mouse model, thymol, but not carvacrol, extended the mean survival of animals. This study indicates the potential of the essential oil of O. onites and its constituents in the treatment of protozoal infections
Essential Oil Composition and Antimicrobial Activities of Tanacetum chiliophyllum (Fisch & Mey.) Schultz Bip. var. monocephalum Grierson from Turkey
WOS: 000299683800015Water-distilled essential oils from aerial parts of Tanacetum chiliophyllum (Fisch. & Mey.) Schultz Bip. var. monocephalum Grierson from Turkey were analyzed by GC and GC/MS. The flower and stem oils were characterized by camphor (17.3%, 10.4%), 1,8-cineole (8.3%, 2.5%) and unknown compounds M+ 218 (6.6%, 10.4%), M+ 220 (Stem: 9.2%). Root oil was characterized with hexadecanoic acid (37.5%), alismol (6.3%), geranyl isovalerate (5.3%). Antibacterial activity of the flower and stem oils were evaluated on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter aerogenes, Proteus vulgaris, Salmonella typhimurium, Staphylococcus epidermis, Bacillus cereus, Bacillus subtilis, and Meticillin resistant S. aureus microorganisms by using a micro-dilution assay. Flower oil inhibited the growth of Bacillus cereus with the MIC 62.5 mu g/mL which was 2 fold less concentration than the positive control chloramphenicol. Both flower and stem oils showed relative toxicity to Vibrio fischeri in the TLC-bioluminescence assay
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