nowadays, many antibiotics are being used to control infectious diseases. inappropriate use of antibiotics leads to emergence of resistant bacteria and problems such as a prolonged course of treatment. medicinal plants and their derivatives, as a good source of treatment, are effective against drug resistance. in this study we have evaluated the antimicrobial activity of herbal essential oils o...

The volatile composition of 20-year-old out-of-service creosote-treated railway wood sleepers was studied. The emitted volatile fraction was collected by means of dynamic purge-and-trap concentration at ambient temperature, and analyzed by comprehensive two-dimensional gas chromatography (GC x GC) hyphenated with mass spectrometric detection systems, using quadrupole (GC x GC/qMS) and time-of-f...

Gas chromatography-atmospheric-pressure chemical ionization-time-of-flight mass spectrometry (GC-APCI-TOFMS) was compared to GC × GC-electron ionization (EI)-TOFMS, GC-EI-TOFMS, GC-chemical ionization (CI)-quadrupole mass spectrometry (qMS), and GC-EI-qMS in terms of reproducibility, dynamic range, limit of detection, and quantification using a mix of 43 metabolites and 12 stable isotope-labele...

Comprehensive 2-dimensional gas chromatography (GC × GC), coupled to either a time of flight mass spectrometry (TOF-MS) or a fast scanning quadrupole MS (qMS) has greatly increased the peak capacity and separation space compared to conventional GC-MS. However, commercial GC × GC-TOFMS systems are not equipped with chemical ionization (CI) and do not provide dominant molecular ions or enable sin...

Identifying non-annotated peaks may have a significant impact on the understanding of biological systems. In silico methodologies have focused on ESI LC/MS/MS for identifying non-annotated MS peaks. In this study, we employed in silico methodology to develop an Isotopic Ratio Outlier Analysis (IROA) workflow using enhanced mass spectrometric data acquired with the ultra-high resolution GC-Orbit...

Various galaxy properties are not continuous over a large range in mass but rather reveal a remarkable transition or “bimodality” at a stellar mass of M,. These properties include colors, stellar populations, X-ray 10 3 # 10 emission, and mass-to-light ratios. This behavior has been interpreted as the transition from hot to cold flows by Dekel & Birnboim. Here we explore whether globular cluste...