Chemical composition and antimicrobial activity of Anthriscus nemorosa root essential oil

The essential oil obtained by hydrodistillation from the roots of Anthriscus nemorosa (Bieb.) Sprengel (Umbelliferae) was analyzed by GC and GC-MS. Among sixty-two compounds identified (representing 89.0% of the total oil), the main components were: n-nonane (12.1%), n-hexadecanol (6.9%), delta-cadinene (6.4%), beta-pinene (6.0%) and germacrene D (5.4%). Furthermore, the antimicrobial activity of the oil was evaluated against the Gram-positive bacteria Staphylococcus epidermidis (ATCC 12228) and Bacillus subtilis (ATCC 6633), the Gram-negative bacterium Escherichia coli (ATCC 25922), and a yeast Candida albicans (ATCC 10259 and ATCC 24433) using the broth microdilution method.     

Voice Characteristics in Adults With Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is an autosomal dominant neurocutaneous disorder caused by mutations in the NF1 gene, which is located at the long arm of chromosome 17. Major characteristics include multiple café-au-lait spots and neurofibromas. Voice abnormalities have been reported to occur in this patient group. However, most studies relied on subjective measurements only. The present study reports the results of an objective voice assessment based on a multiparameter approach in 22 adults with NF1. Aerodynamic measurements, voice range profiles, acoustic voice quality and intonation measurements, and dysphonia severity indices were obtained and compared with data from a control group, consisting of 22 healthy adults. It was found that NF1 patients show a poorer overall voice quality compared with controls. Particularly, a reduction of vital capacity and limitations in laryngeal possibilities with respect to frequency and intensity were observed in the NF1 group.     

Calibration of mass selective detector in non-target analysis of volatile organic compounds in the air

Volatile organic compounds (VOCs) play an important role in the chemistry of the atmosphere and in biogeochemistry. They contribute to the oxidative capacity of the atmosphere, particle and air pollutants, as well as to the production of greenhouse gases (for instance ozone). Among analytical techniques for their determination in the atmosphere gas chromatography coupled with mass spectrometry (GC-MS) offers several advantages. However, for an accurate quantification calibration with standard substances is necessary. A quantitative structure-property relationship (QSPR) model for the prediction of MS response factors was developed on basis of our experimental measurements for the quantification of ozone precursors present in the atmosphere. A linear correlation between chemical structures and response factors was established by using a 7-parameter MLR model. The average error in the prediction of response factors was calculated by cross-validation procedure and was below 20%, which is sufficient for the determination of VOCs in the air. The proposed procedure is time consuming so it is more suited for the quantification of tentatively identified organic compounds during the reprocessing of MS chromatograms in cases when the original sample is no longer available.     

Conjugated circuits currents in hexabenzocoronene and its derivatives formed by joining proximal carbons

We report on calculated CC bond currents for a dozen derivatives of hexabenzocoroenene in which one or more proximal carbon atoms at the molecular periphery have been bridged. The approach that we use is graph‐theoretical in nature, following our outline of this method in 2003, which is based on finding all conjugated circuits in all Kekulé valence structures of these molecules. To the π‐electrons having 4n + 2 π‐electrons are assigned anticlockwise π‐electron currents and to conjugated circuits having 4n π‐electrons are assigned π‐electron currents. One may summarize the results reported in this work by stating that CC bond currents in the compounds considered decrease on going from peripheral rings to the central ring of the molecule, and also that CC bond currents decrease by insertion of bridges to proximal peripheral benzenoid rings. © 2012 Wiley Periodicals, Inc.     

Dual behavior of alcohols in iodine-catalyzed esterification under solvent-free reaction conditions

The dual behavior phenomenon of alcohols in iodine-catalyzed esterification under solvent-free reaction conditions (SFRCs) is described; the governing factor is the stability of the carbonium ion generated from the alcohol; high concentration reaction conditions (HCRCs) or dilute solutions are much less suitable. In the case of benzylic alcohols, loss of optical activity was noted, whereas alkyl alcohols furnished a product with retention of stereochemistry.     

Prediction of different antibacterial activity in a new set of formyl hydroxyamino derivatives with potent action on peptide deformylase using structural information

Due to the essential role of peptide deformylase (PDF) at the bacterial growth cycle, it is a noteworthy target for developing a novel antibacterial agent. In the current study, the antibacterial activities of a set of 44 new structures of formyl hydroxyamino derivatives as PDF inhibitors were quantified using quantitative structure–activity relationship (QSAR). Artificial neural networks (ANN) were used as a chemometrics tool for QSAR modeling. Three quantitative models were suggested to relate the chemical structural features of the formyl hydroxyamino derivatives to their antibacterial activities (pIC₅₀) against Staphylococcus aureus, methicillin-susceptible S. aureus (MSSA), and methicillin-resistant S. aureus (MRSA) peptide deformylase. The sufficiency of the model for prediction of the antibacterial activities of the desired PDF inhibitor compounds against S. aureus, MSSA, and MRSA was statistically demonstrated according to the validation parameters such as coefficient of determination (R²), mean square error (MSE) in training, validation, and prediction sets, and also using applicability domain (AD) and randomization test.

     

Local velocity measurements in a thermally-stratified sodium mixing layer using a permanent-magnet probe

Mean and fluctuating velocities have been measured in a sodium mixing layer experiment, i.e. in a fluid with very low Prandtl number (Pr10⁻²), with a miniature permanent-magnet velocity probe in the presence of strong temperature gradients. A mathematical model for the probe, based upon Faraday's law of induction and including thermoelectric as well as inertia effects due to the finite response time of thermocouples, is presented together with a new dynamic method to compensate for these effects. The sensitivity of the four different probes used in this experiment is in the range of 81–65 (μV/ms⁻¹). Electrical pertubations arising from large-scale thermoelectric effects inside the test section and their influence on the velocity signal are also discussed. The electronic measurement system, combining low noise and high resolution, was specially developed to match the experimental requirements. With this system it was possible to measure velocity RMS-values down to 1 mm/s corresponding to a voltage of 100 nV, and mean velocities with an accuracy of about 6 mm/s. This paper deals with the peculiarities of the measurement technique and its performance, but does not analyze the experimental results, which will be presented in a separate publication.     

Skew-symmetric functions on the hyperboloid and quantum measures

Measures on the logic ofJ-projections on an indefinite metric space of dimension two are studied.     

Outcome of mTHPC mediated photodynamic therapy is primarily determined by the vascular response

We have previously shown that the efficacy of photodynamic therapy (PDT) using the photosensitizer meso-tetra-hydroxyphenyl-chlorin (mTHPC) correlated with plasma drug levels at the time of illumination rather than drug levels in human tumor xenografts or mouse skin. These results suggested that vascular-mediated effects could be important determinants of PDT response in vivo. In the present study we further investigated the relationship between PDT response, mTHPC pharmacokinetics and the localization and extent of vascular damage induced in human squamous cell carcinoma xenografts (HNXOE). Plasma levels of mTHPC decreased exponentially with time after injection, whereas tumor drug levels remained maximal for at least 48 h. At 3 h after administration mTHPC was localized in the blood vessels, whereas at later times it was distributed throughout the whole tumor. Illumination at 3 h after mTHPC, which resulted in 100% long-term tumor cure, led to a marked reduction of vascular perfusion and increased tumor hypoxia at 1 h after treatment. Illumination at 48 h resulted in rapid regrowth of most tumors and only 10% cure. This protocol did not affect a significant decrease in vascular perfusion or increase in tumor hypoxia. These data show that optimal responses to mTHPC-mediated PDT were primarily dependent on the early vascular response, and that plasma drug levels at the time of illumination could predict this relationship.