In Vitro Activity of Essential Oils Distilled from Colombian Plants against Candida auris and Other Candida Species with Different Antifungal Susceptibility Profiles

Multi-drug resistant species such as Candida auris are a global health threat. This scenario has highlighted the need to search for antifungal alternatives. Essential oils (EOs), or some of their major compounds, could be a source of new antifungal molecules. The aim of this study was to evaluate the in vitro activity of EOs and some terpenes against C. auris and other Candida spp. The eleven EOs evaluated were obtained by hydro-distillation from different Colombian plants and the terpenes were purchased. EO chemical compositions were obtained by gas chromatography/mass spectrometry (GC/MS). Antifungal activity was evaluated following the CLSI standard M27, 4th Edition. Cytotoxicity was tested on the HaCaT cell line and fungal growth kinetics were tested by time–kill assays. Candida spp. showed different susceptibility to antifungals and the activity of EOs and terpenes was strain-dependent. The Lippia origanoides (thymol + p-cymene) chemotype EO, thymol, carvacrol, and limonene were the most active, mainly against drug-resistant strains. The most active EOs and terpenes were also slightly cytotoxic on the HaCaT cells. The findings of this study suggest that some EOs and commercial terpenes can be a source for the development of new anti-Candida products and aid the identification of new antifungal targets or action mechanisms.     

Biodegradation studies of <Emphasis Type="Italic">N</Emphasis><Superscript>4</Superscript>-acetylsulfapyridine and <Emphasis Type="Italic">N</Emphasis><Superscript>4</Superscript>-acetylsulfamethazine in environmental water by applying mass spectrometry techniques

This work evaluates the biodegradation of N ⁴-acetylsulfapyridine (AcSPY) and N ⁴-acetylsulfamethazine (AcSMZ), metabolites of two of the most commonly used sulfonamides (SAs) in human and veterinary medicine, respectively. Aerobic transformation in effluent wastewater was simulated using aerated fixed-bed bioreactors. No visible changes in concentration were observed in the AcSMZ reactor after 90 days, whereas AcSPY was fully degraded after 32 days of experiment. It was also demonstrated that AcSPY transformed back to its parent compound sulfapyridine (SPY). The environmental presence of these two metabolites in wastewater effluent had been previously investigated and confirmed, together with three more SA acetylated metabolites and their corresponding parent compounds, in 18 different wastewater treatment plants in Hesse (Germany). Sulfamethoxazole (SMX) and SPY were the two SAs detected most frequently (90% and 89% of the samples, respectively) and in the highest concentrations (682 ng L⁻¹ for SMX and 532 ng L⁻¹ for SPY). To conclude, hazard quotients were calculated whenever toxicity data were available. None of the SAs studied posed an environmental risk.     

Decomposition of BL-chains

A simple and self contained proof of decomposition of BL-chains into ordinal sums of Wajsberg hoops is given.Received October 23, 2003; accepted in final form September 11, 2004.     

Health implications of nanoparticles

Nanoparticles are increasingly used in a wide range of applications in science, technology and medicine. Since they are produced for specific purposes which cannot be met by larger particles and bulk material they are likely to be highly reactive, in particular, with biological systems. On the other hand a large body of know-how in environmental sciences is available from toxicological effects of ultrafine particles (smaller than 100 nm in size) after inhalation. Since nanoparticles feature similar reactivity as ultrafine particles a sustainable development of new emerging nanoparticles is required. This paper gives a brief review on the dosimetry of nanoparticles, including deposition in the various regions of the respiratory tract and systemic translocation and uptake in secondary target organs, epidemiologic associations with health effects and toxicology of inhaled nanoparticles. General principles and current paradigms to explain for the specific behaviour of nanoparticles in toxicology are discussed. With that respect we consider nanoparticles to be in the range from 1 to 2 nm (clusters of atoms/molecules) to particles that are smaller than 100 nm at least in one dimension. Since the evidence for health risks of ultrafine and nanoparticles after inhalation has been increasing over the last decade, the paper attempts to extrapolate these findings and principles observed in particle inhalation toxicology into recommendations for an integrated concept of risk assessment of nanoparticles for a broad range of use in science, technology and medicine.Based on this article a book chapter will appear soon (Kreyling et al., 2006).     

Chemisorption of atomic hydrogen in graphite and carbon nanotubes

An orthogonal tight-binding model of the carbon-hydrogen interaction was modified to deal with the different hybridization states of atomic hydrogen on carbon surfaces, without explicitly including charge self-consistency. The resulting model has great flexibility and computational efficiency, generally with a good quantitative accuracy. The non-self-consistent C-H model was tested by calculating structural properties of small hydrocarbons and simple polymers, and against ab initio results of H binding to both perfect and defective graphite. The model was employed to study the chemisorption properties and dynamics of atomic hydrogen on perfect and defective surfaces of graphite and carbon nanotubes.     

Extraction and Preconcentration of the Herbicide Glyphosate and its Metabolite AMPA Using Anion-Exchange Solid Phases

An extraction and preconcentration method has been developed for the determination of glyphosate and its degradation product, aminomethylphosphonic acid (AMPA), over a broad range of concentrations (0.1–500 μg · L⁻¹) in various aqueous matrices which differ in their ionic content. Two anion-exchange resins (the microporous Amberlite^?IRA-416 and the macroporous Amberlite^?IRA-900) and a commercial silica modified cartridge, ISOLUTE-NH₂, were evaluated and compared. The effect of flow-rate, composition and volume of the elution solution, analyte concentration, sample volume and porosity of the sorbents were investigated and the best experimental conditions were then used in the recovery of the analytes from spiked natural waters. Determination of the analytes was performed by HPLC with fluorescence detection, using FMOC-Cl as a pre-column derivatisation agent. Enrichment factors of up to 125 were achieved with the protonated ISOLUTE-NH₂ cartridge allowing the determination of glyphosate at a level of 0.1 μg · L⁻¹. Recovery rates of 99% for glyphosate and 77% for AMPA and relative standard deviations for repeatability of <10% for both analytes were determined with the Amberlite^?IRA-900 macroporous resin.     

Correction to: Ethylethanolammonium 4-nitrobenzoate

Journal of Thermal Analysis and Calorimetry - The temperature dependence of molar heat capacity of Ba1.5Fe2(PO4)3 phosphate was investigated between T&nbsp;=&nbsp;6 and 670&nbsp;K with...     

New addition and cyclization reactions involving phosphorus based allenes

In this paper, we describe convenient methods for functionally active phenol addition reaction of allenylphosphonates/allenyl phosphine oxides. These reactions lead to either vinyl or allylphosphonates. In the reaction α-aryl allenylphosphonates with 2-iodophenol in the presence of Pd nanoparticles [Pd-PVP] isomeric vinylphosphonates are preferentially obtained. A novel cyclization reaction of 2-iodo-t-butylbenzaldimine with and allenylphosphine oxide that leads to an isoquinoline is also discovered; the product is characterized by single crystal X-ray structure determination.     

TiO2 Nanotubes: Nitrogen‐Ion Implantation at Low Dose Provides Noble‐Metal‐Free Photocatalytic H2‐Evolution Activity

Low‐dose nitrogen implantation induces an ion and damage profile in TiO₂ nanotubes that leads to “co‐catalytic” activity for photocatalytic H₂‐evolution (without the use of any noble metal). Ion implantation with adequate parameters creates this active zone limited to the top part of the tubes. The coupling of this top layer and the underlying non‐implanted part of the nanotubes additionally contributes to an efficient carrier separation and thus to a significantly enhanced H₂ generation.