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The study examines the measurement methods for determining nano and non-nano materials in sun protection products. It is found that Tier-1 methods such as AF4 are not able to detect particles in agglomerates. Therefore, a Tier-2 method such as TEM is required to confirm the non-nano properties of a material. The study uses the decision support scheme of the NanoDefine project to analyze the particle size distribution of titanium dioxide and zinc oxide types. It emphasizes that the correct determination of nano and non-nano materials is crucial for the approval of sun protection products. [Extracted from the article]

Despite the UV performance benefits of particulate UV filters, concerns have been raised over their potential percutaneous permeation leading to the requirement of a specific approval for all nano UV filters in Europe. Under the legally binding definition of the Cosmetic regulation No. 1223/2009, nanomaterial means a material on the scale from 1 to 100 nm. The recommendation of the European Commission (2011/696/EU) revised 10th of June 2022 (2022/C229/01) further specifies that a material is nano when at least 50% of the number size distribution of the constituent particles is comprised between 1 and 100 nm. The situation for Titanium Dioxide and Zinc Oxide is confusing since the constituent particles are often part of agglomerates. Some suppliers clearly specify the nano feature of their material, while others declare the non-nano property of their inorganic products. The objective of this study was, therefore, to measure the number-based particle size distribution of three marketed Titanium Dioxide and Zinc Oxide grades using the decision support flow scheme devised by the NanoDefine project. This group was created to support the identification of nanomaterials as required by the European legislation. We employed the tier 1 method asymmetrical flow field-flow fractionation (AF4) coupled with UV and IC-PMS (inductively coupled plasma mass spectroscopy) detectors and tier 2 method transmission electron microscopy (TEM). The study clearly taught that the samples that appeared to be non-nanomaterials with AF4-IC-PMS measurements were finally proven to be nanomaterials using the TEM tier 2 method. Relying only on tier 1 methodologies such as AF4, X-Ray Disc Centrifuge or Dynamic Light Scattering to determine the non-nano property of a material is insufficient, since tier 1 methods are not able to detect constituent particles as part of agglomerates, which is often the case for Titanium Dioxide and Zinc Oxide. The status of being a non-nanomaterial can, in this case, only be certified with a tier 2 technique, particularly electron microscopy. [ABSTRACT FROM AUTHOR]

Apart from long-known and applied nanostructures like carbon black for tyres or pigments for coatings nanotechnology has created highly sophisticated structures used for nano/molecular electronics, diagnostics, drug delivery, UV-absorbers etc. Often the main question to be solved analytically is the local determination of tiny amounts of chemicals resulting in an ever increasing need for highly sensitive as well as locally resolved techniques. Applications of techniques like mass spectroscopy, transmission electron microscopy as well as ultracentrifugation to problems arising from nanotechnology in the chemical industry will be described. [ABSTRACT FROM AUTHOR]

Manipulation of the input pulse chirp during supercontinuum generation in tapered fibers provides precise control of the soliton fission process taking place in the taper waist. Simulations and experiments demonstrate that controlling this pre-chirp by a pulse shaper can be applied to compensate for deleterious effects due to untapered fiber pigtails. Temporal and cross-correlation frequency resolved measurements are utilized to show, that the control of the soliton fission dynamics can be obtained by manipulating the input pulse chirp through the imposition of a quadratic spectral phase. [ABSTRACT FROM AUTHOR]

We report on the application of shaped femtosecond pulses on low-field chirped excitation of an atomic two-level system. The induced transient phenomena can be considered as a phase diagram of the excitation pulse. Their high sensitivity to the phase-modulated pulse is analyzed, by comparing numerical solutions of the time-dependent Schrödinger equation with experimental results. These coherent transients allow for high precision calibration of pulse-shaping setups where usual methods are less efficient. As an illustration, a comparison between 128-pixel and 640-pixel spatial light modulator pulse shapers is given. [ABSTRACT FROM AUTHOR]

Glycopeptide antibiotics are a class of widely known natural compounds produced by Actinomycetes. Vancomycin, the first member of the glycopeptide family to be discovered, was described in 1955 and used as an antibiotic soon thereafter. During the past 50 years numerous contributions on the structure, mode of action, and therapeutic features of vancomycin have been published. Recently, there has been considerable progress in elucidating the biosynthesis of glycopeptide antibiotics by combining molecular biology and analytical chemistry methods. Here, we provide an overview of the current knowledge regarding biosynthetic glycopeptide assembly. [ABSTRACT FROM AUTHOR]

The pulse response of an optically excited vertical-cavity surface-emitting laser is optimized by shaping the pump pulse. The temporal phase and amplitude of the excitation are adjusted by a learning loop with live spectrotemporal monitoring of excitation and emission pulses using a streak camera. The genetic algorithm of the loop is inspired by the optimization occurring in evolution in biology. The pulse response is such decreased from 4.8 to 2 ps. Emission intensity shows strong correlation with the pulse delay and also improves by 63%. [ABSTRACT FROM AUTHOR]

Clinical presentation the vibrational dynamics in crystalline polydiacetylene is demonstrated by tailoring the Stokes pulse of a coherent anti-Stokes Raman scattering (CARS) setup in a feedback-controlled self-learning loop. The feedback signal is derived from the spectral distribution of the CARS signal. Controlled excitation of one mode and simultaneous extinction of all other modes with high efficiency is demonstrated. In addition, the relative phases of the three normal modes have been controlled allowing excitations of local modes and suggesting the possibility of ground state reaction control. [ABSTRACT FROM AUTHOR]

Research efforts in the past two decades have resulted in thousands of potential application areas for nanoparticles – which materials have become industrially relevant? Where are sustainable applications of nanoparticles replacing traditional processing and materials? This tutorial review starts with a brief analysis on what makes nanoparticles attractive to chemical product design. The article highlights established industrial applications of nanoparticles and then moves to rapidly emerging applications in the chemical industry and discusses future research directions. Contributions from large companies, academia and high-tech start-ups are used to elucidate where academic nanoparticle research has revolutionized industry practice. A nanomaterial-focused analysis discusses new trends, such as particles with an identity, and the influence of modern instrument advances in the development of novel industrial products. [ABSTRACT FROM AUTHOR]

Abstract: Colloidal quantum dots (QD) show great promise as fluorescent markers. The QD used in this study were obtained in aqueous medium rather than the widely used colloidal QD. Both methodologies used for the production of QD are associated with the presence of heavy metals such as cadmium (Cd). Here we investigate the short-term inhalation toxicity of water-soluble core-shell CdS/Cd(OH)2 QD. Male Wistar rats were head-nose exposed for 6h/day on 5 days at the technically maximum concentration (0.52mgCd/m3). Histological examination was performed directly after the last exposure. Additional rats were used for Cd organ burden determinations. Clinical parameters in blood, bronchoalveolar lavage fluid and lung tissue were determined 3 days after the last exposure. To analyze the reversibility or progression of effects, the examinations were performed again after a recovery period of 3 weeks. The results of the study indicate that CdS/Cd(OH)2 QD caused local neutrophil inflammation in the lungs that partially regressed after the 3-week recovery period. There was no evidence that QD were translocated to the central nervous system nor that a systemic acute phase response occurred. [Copyright &y& Elsevier]

All known gene clusters for glycopeptide antibiotic biosynthesis contain a conserved gene supposed to encode an ABC-transporter. In the balhimycin-producer Amycolatopsis balhimycina this gene ( tba) is localised between the prephenate dehydrogenase gene pdh and the peptide synthetase gene bpsA. Inactivation of tba in A. balhimycina by gene replacement did not interfere with growth and did not affect balhimycin resistance. However, in the supernatant of the tba mutant RM43 less balhimycin was accumulated compared to the wild type; and the intra-cellular balhimycin concentration was ten times higher in the tba mutant RM43 than in the wild type. These data suggest that the ABC transporter encoded in the balhimycin biosynthesis gene cluster is not involved in resistance but is required for the efficient export of the antibiotic. To elucidate the activity of Tba it was heterologously expressed in Escherichia coli with an N-terminal His-tag and purified by nickel chromatography. A photometric assay revealed that His6-Tba solubilised in dodecylmaltoside possesses ATPase activity, characteristic for ABC-transporters. [ABSTRACT FROM AUTHOR]

Streptomyces coelicolor A3(2) has three additional glnA-type genes besides the glutamine synthetase genes glnA (encoding GSI) and glnII (encoding GSII). The aim of this work was to characterize their functional properties and regulation. Sequence analyses revealed that GlnA2, GlnA3, and GlnA4 are dissimilar to S. coelicolor GSI and lack highly conserved amino acid residues involved in catalysis. In heterologous expression experiments, glnA2, glnA3, and glnA4, in contrast to glnA and glnII, were not capable of complementing the l-glutamine auxotrophy of an Escherichia coli glnA mutant. The lack of a conserved sequence motif reflecting adenylylation control of enzyme activity suggests that GlnA2, GlnA3, and GlnA4 are not regulated via adenylyltransferase-mediated modification. In DNA-binding assays, the OmpR-like regulator of nitrogen metabolism GlnRII, which interacts with the glnA and glnII promoters, did not bind to the upstream regions of glnA2, glnA3, and glnA4. These findings support the conclusion that glnA2, glnA3, and glnA4 are not directly involved in l-glutamine synthesis and nitrogen assimilation and are not subject to nitrogen control in S. coelicolor. The glnA3 gene product is similar to FluG, which is required for asexual sporulation in Aspergillus nidulans. However, inactivation of glnA3 does not block morphological differentiation in S. coelicolor. [ABSTRACT FROM AUTHOR]

We stir with a focused laser beam a Bose-Einstein condensate of [sup 87]Rb atoms confined in a magnetic trap. We observe the formation of a single vortex for a stirring frequency exceeding a critical value. At larger rotation frequencies we produce states of the condensate for which up to eleven vortices are simultaneously present. We present measurements of the decay of a vortex array once the stirring laser beam is removed. [ABSTRACT FROM AUTHOR]

Review: 49 refs. [ABSTRACT FROM AUTHOR]

Highlights: [•] We examined the inhalation toxicity and translocation ability of coated CdS/Cd(OH)2 quantum dots in rats. [•] Broncho-alveolar lavage fluid examinations and microscopy were performed. [•] Inflammatory process was observed by examination of broncho-alveolar lavage fluid. [•] Quantum dots caused less toxicity compared to compounds with larger particle sizes. [•] No translocation of the particles from lung to other organs were observed. [•] Small particle sizes are not the only factor triggering the toxic response or translocation. [Copyright &y& Elsevier]

Abstract: Bacterial secondary metabolites are an important source of antimicrobial and cytostatic drugs. These molecules are often synthesized in a stepwise fashion by multimodular megaenzymes that are encoded in clusters of genes encoding enzymes for precursor supply and modification. In this work, we present an open source software pipeline, CLUSEAN (CLUster SEquence ANalyzer) that helps to annotate and analyze such gene clusters. CLUSEAN integrates standard analysis tools, like BLAST and HMMer, with specific tools for the identification of the functional domains and motifs in nonribosomal peptide synthetases (NRPS)/type I polyketide synthases (PKS) and the prediction of specificities of NRPS. [Copyright &y& Elsevier]

Streptomycetes are the most important bacterial producers of bioactive secondary metabolites such as antibiotics or cytostatics. Due to the emerging resistance of pathogenic bacteria to all commonly used antibiotics, new and modified natural compounds are required for the development of novel drugs. In addition to the classical screening for natural compounds, genome driven approaches like combinatorial biosynthesis are permanently gaining relevance for the generation of new structures. This technology utilizes the combination of genes from different biosynthesis pathways resulting in the production of novel or modified metabolites. The basis for this strategy is the access to a significant number of genes and the knowledge about the activity and specificity of the enzymes encoded by them. A joint initiative was started to exploit the biosynthesis gene clusters from streptomycetes. In this publication, an overview of the strategy for the identification and characterization of numerous biosynthesis gene clusters for polyketides displaying interesting functions and particular structural features is given. [Copyright &y& Elsevier]

Summary Streptomyces coelicolor has an unusually large arsenal of glutamine synthetase (GS) enzymes: a prokaryotic GSI-β-subtype enzyme (encoded by glnA ), three annotated glnA -like genes of the GSI-α-subtype and a eukaryote-like glutamine synthetase II (encoded by glnII ). Under all tested conditions, GSI was found to represent the dominant glutamine synthetase activity. A significant heat-labile GSII activity, which is very low to undetectable in liquid-grown cultures, was only detected in morphologically differentiating S. coelicolor cultures. Analysis of glnA and glnII transcription by S1 nuclease mapping and egfp fusions revealed that, on nitrogen-limiting solid medium, glnII but not glnA expression is upregulated. An OmpR-like regulator protein, GlnR, has previously been implicated in transcriptional control of glnA expression. Gel retardation analysis revealed that GlnR is a DNA-binding protein, which interacts with the glnA promoter. It is not autoregulatory and does not bind to the upstream regions of the glnA -like genes of the α-subfamily, nor to the glnII promoter in vitro . A second GlnR target was identified upstream of the amtB gene, encoding a putative ammonium transporter. amtB forms an operon with glnK (encoding a PII protein) and glnD (encoding a putative PII nucleotidylyltransferase) shown by S1 nuclease protection analysis and reverse transcription-polymerase chain reaction (RT-PCR). An amtB and glnA promoter alignment revealed a putative GlnR operator structure. Downstream of glnII , a gene encoding for another OmpR-like regulator, GlnRII, was identified, with strong similarity to GlnR. Gel shifts with GlnRII showed that the promoters recognized by GlnR are also targets of GlnRII. However, GlnRII also interacted with the glnII upstream region. Only inactivation of glnR resulted in a glutamine auxotrophic phenotype, whereas the glnRII mutant can grow on minimal medium without glutamine. [ABSTRACT FROM AUTHOR]

Summary Glutamine synthetase I (GSI) enzyme activity in Streptomyces coelicolor is controlled post-translationally by the adenylyltransferase (GlnE) as in enteric bacteria. Although other homologues of the Escherichia coli Ntr system ( glnK , coding for a PII family protein; and glnD , coding for an uridylyltransferase) are found in the S. coelicolor genome, the regulation of the GSI activity was found to be different. The functions of glnK and glnD were analysed by specific mutants. Surprisingly, biochemical assay and two-dimensional PAGE analysis showed that modification of GSI by GlnE occurs normally in all mutant strains, and neither GlnK nor GlnD are required for the regulation of GlnE in response to nitrogen stimuli. Analysis of the post-translational regulation of GlnK in vivo by two-dimensional PAGE and mass spectrometry indicated that it is subject to both a reversible and a non-reversible modification in a direct response to nitrogen availability. The irreversible modification was identified as removal of the first three N-terminal amino acid residues of the protein, and the reversible modification as adenylylation of the conserved tyro-sine 51 residue that is known to be uridylylated in E. coli . The glnD insertion mutant expressing only the N-terminal half of GlnD was capable of adenylylating GlnK, but was unable to perform the reverse deadenylylation reaction in response to excess ammonium. The glnD null mutant completely lacked the ability to adenylylate GlnK. This work provides the first example of a PII protein that is modified by adenylylation, and demonstrates that this reaction is performed by a homologue of GlnD, previously described only as a uridylyltransferase enzyme. [ABSTRACT FROM AUTHOR]

We present the first simultaneous trapping of two different ultracold atomic species in a conservative trap. Lithium and cesium atoms are stored in an optical dipole trap formed by the focus of a CO[sub 2] laser. Techniques for loading both species of atoms are discussed and observations of elastic and inelastic collisions between the two species are presented. A model for sympathetic cooling of two species with strongly different mass in the presence of slow evaporation is developed. From the observed Cs-induced evaporation of Li atoms we estimate a cross-section for cold elastic Li-Cs collisions. [ABSTRACT FROM AUTHOR]

Characterizes a phosphinothricin tripeptide (PTT) biosynthesis-specific aconitase-like gene in Streptomyces viridochromogenes. Role of tricarboxylic acid cycle in PTT biosynthesis; Structure of PTT and balaphos; Catalyzation of phosphinomethylmalate by primary metabolism.