Search

Several Re(I)pyca conjugates incorporating long aliphatic amines have been synthesized through a one-pot methodology. The compounds have been fully characterized, and seven compounds have been structurally elucidated by single crystal X-ray diffraction. The C(14) variant was probed as a potential organometallic IR dye. Large unilamellar vesicles were generated with DOPC and the C(14) compound and we observed incorporation of the rhenium complex as observed by FTIR microscopy.

Daylight fluorescent pigments are complex artists’ colorants made of multiple admixed dyes and additives infused in a polymer resin. Their unique photochemistry creates interesting optical effects that make them appealing for a range of applications. The wavelength dependence of the dyes’ emissive properties has also led to their use in works meant to be displayed under nontraditional high energy light sources, such as blacklights. The intended display methods and the photochemistry of the constituent dyes can lead to chemical instability and also pose unique challenges for conservation and exhibition. In Part 1 of this research, we reported on the chemical constituents of colorants from two major manufacturers. In this paper, we provide a comprehensive report of the spectral properties and lightfastness of paints prepared with the pigments. The optical properties and chemical stability of these colorants are correlated with the composition. Variation in composition can lead to unique markers that could be useful for conservation treatment and exhibition considerations. Changes in the dyes used in the pigment formulation over time are considered in the comparison of two objects: a Stephen Sprouse silvered leather motorcycle jacket featuring fluorescent art by Stefano Castronovo and selections from the Day-Glo Designer’s Guide from 1969.

Subduction and exhumation are key processes in the formation of orogenic systems across the world, for example, in the European Alps. For geophysical investigations of these orogens, it is essential to understand the petrophysical properties of the rocks involved. These are the result of a complex interaction of mineral composition and rock fabric including mineral textures (i.e., crystallographic preferred orientations). In this study we present texture-derived elastic anisotropy data for a representative set of different lithologies involved in the Alpine orogeny. Rock samples were collected in the Lago di Cignana area in Valtournenche, in the Italian northwestern Alps. At this locality a wide range of units of continental and oceanic origin with varying paleogeographic affiliations and tectono-metamorphic histories are accessible. Their mineral textures were determined by time-of-flight neutron diffraction. From these data the elastic properties of the samples were calculated. The data set includes representative lithologies from a subduction-exhumation setting. In subducted lithologies originating from the oceanic crust, the P-wave anisotropies (AVPs [%]) range from 1.4 % to 3.7 % with average P-wave velocities of 7.20–8.24 km/s and VP / VS ratios of 1.70–1.75. In the metasediments of the former accretionary prism the AVPs range from 3.7 % to 7.1 %, average P-wave velocities are 6.66–7.23 km/s and VP / VS ratios are 1.61–1.76. Continental crust which is incorporated in the collisional orogen shows AVP ranging from 1.4 % to 2.1 % with average P-wave velocities of 6.52–6.62 km/s and VP / VS ratios of 1.56–1.60. Our results suggest that mafic and felsic rocks in subduction zones at depth may be discriminated by a combination of seismic signatures: lower anisotropy and higher VP / VS ratio for mafic rocks, and higher anisotropy and lower VP / VS ratio for felsic rocks and metasediments.

Organic electron transfer molecules are of interest for potential use in solar capturing and as model systems for understanding the fundamentals of photo-induced charge transfer. One small model system for photo-induced electron transfer is p-aminobenzoic acid derivatives. The modification of the electron acceptor moiety to halogenate the ester chain and thionation of the ester using Curphey’s regent are reported. The electronic properties are assessed through both computational modeling and spectroscopic measurements. The modifications allow tuning of the spectroscopic properties of the system, shifting absorbance to the red upon formation of the thionester and a concurrent decrease in the fluorescence quantum efficiency.

The shift from artificial to natural ingredients is a rising trend in the food industry. However, natural coloring agents tend to be less stable than their synthetic counterparts when exposed to light, air, changes in pH, and heat. This study compares the photostability of three organic red dyes, Red 40 (allura red AC), betanin and carminic acid, in aqueous and soft drink solutions. The degradation, traced through absorbance spectroscopy, is well fit to first-order kinetics. Two distinct timescales are observed in aqueous solution but only a single, faster decay in the soft drink matrix. Betanin is the least stable dye in both solvent environments and Red 40 exhibits the greatest destabilization in the soft drink solution. Anoxia has different impacts dependent upon both the dye and solvent system. The analysis provides further insight into the degradation mechanisms for these different red dyes and the role of environment on their photostability.

Hintergrund Das thorakale Aortenaneurysma ist durch eine Dilatation der Aorta ascendens und durch eine Neigung zu Dissektionen der Aorta ascendens oder der Aorta descendens gekennzeichnet („Thoracic Aortic Aneurysms and Dissections, TAAD“). Bis zu 20 % der Falle sind familiar und folgen dann in der Regel einem autosomal-dominanten Erbgang.

The fundamental chemistry underlying the photo-induced degradation of cochineal (carmine), a red dye extracted from South American scale insects and used as an artist colorant, and its stability in solution and as a lake pigment in different paint media exposed to light in various ambient environments is examined. The influence of oxygen on the photodegradation was examined for dye solutions and for solid paint samples containing the lake pigment, and the effect of ambient humidity was assessed for the paint samples. The degradation was followed using absorbance spectroscopy, and characterized using IR and LC-MS. Results indicate lower reaction rates of the carminic acid chromophore in solution and in oil paints during light exposure in anoxic conditions; whereas watercolor paints demonstrated a stronger dependence of the rates on the ambient humidity. A ring opening of the anthraquinone core is suggested in the breakdown of the dye and pigment. This study illustrates that solution phase systems may serve as simple models to assess the kinetics and mechanism of photochemical breakdown of organic-based pigments in solid samples.

Recently, the binding kinetics of a ligand-target interaction, such as the residence time of a small molecule on its protein target, are seen as increasingly important for drug efficacy. Here, we investigate these concepts to explain binding and proton blockage of rimantadine variants bearing progressively larger alkyl groups to influenza A virus M2 wild type (WT) and M2 S31N protein proton channel. We showed that resistance of M2 S31N to rimantadine analogues compared to M2 WT resulted from their higher koff rates compared to the kon rates according to electrophysiology (EP) measurements. This is due to the fact that, in M2 S31N, the loss of the V27 pocket for the adamantyl cage resulted in low residence time inside the M2 pore. Both rimantadine enantiomers have similar channel blockage and binding kon and koff against M2 WT. To compare the potency between the rimantadine variants against M2, we applied approaches using different mimicry of M2, i.e., isothermal titration calorimetry and molecular dynamics simulation, EP, and antiviral assays. It was also shown that a small change in an amino acid at site 28 of M2 WT, which does not line the pore, seriously affects M2 WT blockage kinetics. © 2018 American Chemical Society.

The photophysical properties of p -aminobenzoic acid and dimethyl- p -aminobenzoic acid are compared in a range of solvents. The electronic spectra are used to determine quantum efficiencies and evaluate excited state behavior. The latter system is found to undergo a charge transfer following photoexcitation and the thermodynamics for the process are assessed. The strength and type of solvent–solute interaction are important in determining the driving force for the charge transfer, with entropy being dominant in protic solvents and enthalpy in aprotic solvents. Vibrational spectroscopy and calculations provide further insight into the nature of the specific solvent–solute interactions, with shifts in the infrared spectrum observed due to hydrogen bonding interactions with the solvent.

Naphthoquinone amino derivatives exhibit interesting physicochemical properties and are of interest for potential medicinal purposes. The preparation of novel 2-(nitrophenylamino)-1,4-naphthoquinones derivatives was achieved by reaction of nitroanilines with 1,4-naphthoquinone with a catalytic amount of FeCl 3 or by direct nitration of 2-(phenylamino)-1,4-naphthoquinone (PAN). Structural and photophysical properties of a series of NO 2 PANs and FPANs derivatives are examined using computational and spectroscopic methods. Absorbance and emission spectra are measured in a range of solvent environments to examine the impact of solvent–solute interactions. Additionally quantum calculations are used to evaluate the electronic nature of the spectral transitions and compare structures of the different PAN derivatives. The lowest energy electronic transitions have charge transfer character, and show the most sensitivity to solvent and substituents. Higher energy π–π * transitions are relatively insensitive to both factors. Computational predictions are in good agreement with the experimental spectra, and provide molecular-level insight variations amongst the different aniline-substituents.

Full text is available as a scanned copy of the original print version.

Resurgence of pertussis was not directly correlated with changes in vaccine composition or schedule., Since the 1980s, pertussis notifications in the United States have been increasing. To determine the types of Bordetella pertussis responsible for these increases, we divided 661 B. pertussis isolates collected in the United States during 1935–2009 into 8 periods related to the introduction of novel vaccines or changes in vaccination schedule. B. pertussis diversity was highest from 1970–1990 (94%) but declined to ≈70% after 1991 and has remained constant. During 2006–2009, 81.6% of the strains encoded multilocus sequence type prn2-ptxP3-ptxS1A-fim3B, and 64% were multilocus variable number tandem repeat analysis type 27. US trends were consistent with those seen internationally; emergence and predominance of the fim3B allele was the only molecular characteristic associated with the increase in pertussis notifications. Changes in the vaccine composition and schedule were not the direct selection pressures that resulted in the allele changes present in the current B. pertussis population.

The local environment dictates the structural and functional properties of many important chemical and biological systems. The impact of pH on the photophysical properties of a series of para-aminobenzoic acids is examined using a combination of experimental spectroscopy and quantum chemical calculations. Following photoexcitation, PABA derivatives may undergo an intramolecular charge transfer (ICT) resulting in the formation of a zwitterionic species. The thermodynamics of the excited state reaction and temperature-dependence of the radiative emission processes are evaluated through variable temperature fluorescence spectroscopy carried out in a range of aqueous buffers. Quantum chemical calculations are used to analyze structural changes with modifications at the amine position and different protonation states. The ICT is only observed in the tertiary amine, which calculations show has more sp(2) character than the primary or secondary amines. Thermodynamic analysis indicates the ICT reaction is driven by entropy.

The effect a solvent has on the photophysical properties of a series of benzophenone derivatives, all FDA approved for use in sunscreens, is examined. Experimentally significant differences in the solvatochromic behavior are found to be dependent upon the substituents on the parent benzophenone molecule. The spectral trends do not appear to originate from only changes in the solvent polarity but indicate that specific solvent-solute interactions influence the absorbance energies of some benzophenones. Computational investigations examine the structure and electronic excitation energies of the molecules. Specific interactions of the solvent and solute are modeled to evaluate structural changes that result from solvent-solute complexation and the impact of the changes upon absorbance properties. The viability of an intramolecular excited state proton transfer is theoretically evaluated. The combination of experimental and computational analysis provides a more complete understanding of the molecular level origin of the unique photophysical properties of this class of UV absorbers.

The objective of this study was to develop a canonical, parsimoniously-informative SNP panel for subtyping Shiga-toxin producing Escherichia coli (STEC) O157:H7 that would be consistent with epidemiological, PFGE, and MLVA clustering of human specimens. Our group had previously identified 906 putative discriminatory SNPs, which were pared down to 391 SNPs based on their prevalence in a test set. The 391 SNPs were screened using a high-throughput form of TaqMan PCR against a set of clinical isolates that represent the most diverse collection of O157:H7 isolates from outbreaks and sporadic cases examined to date. Another 30 SNPs identified by others were also screened using the same method. Two additional targets were tested using standard TaqMan PCR endpoint analysis. These 423 SNPs were reduced to a 32 SNP panel with the almost the same discriminatory value. While the panel partitioned our diverse set of isolates in a manner that was consistent with epidemiological data and PFGE and MLVA phylogenies, it resulted in fewer subtypes than either existing method and insufficient epidemiological resolution in 10 of 47 clusters. Therefore, another round of SNP discovery was undertaken using comparative genomic resequencing of pooled DNA from the 10 clusters with insufficient resolution. This process identified 4,040 potential SNPs and suggested one of the ten clusters was incorrectly grouped. After its removal, there were 2,878 SNPs, of which only 63 were previously identified and 438 occurred across multiple clusters. Among highly clonal bacteria like STEC O157:H7, linkage disequilibrium greatly limits the number of parsimoniously informative SNPs. Therefore, it is perhaps unsurprising that our panel accounted for the potential discriminatory value of numerous other SNPs reported in the literature. We concluded published O157:H7 SNPs are insufficient for effective epidemiological subtyping. However, the 438 multi-cluster SNPs we identified may provide the additional information required.

Mutations within the structural gene ofampDcan lead to AmpC overproduction and increases in β-lactam MICs in organisms with an inducibleampC. However, identification of mutations alone cannot predict the impact that those mutations have on AmpD function. Therefore, a model system was designed to determine the effect ofampDmutations on ceftazidime MICs using an AmpD−mutantEscherichia colistrain which produced an inducible plasmid-encoded AmpC.ampDgenes were amplified by PCR from strains ofE. coli,Citrobacter freundii, andPseudomonas aeruginosa. Also, carboxy-terminal truncations ofC. freundii ampDgenes were constructed representing deletions of 10, 21, or 25 codons. AmplifiedampDproducts were cloned into pACYC184 containing inducibleblaACT-1-ampR. Plasmids were transformed intoE. colistrains JRG582 (AmpD−) and K-12 259 (AmpD+). The strains were evaluated for a derepressed phenotype using ceftazidime MICs. Some mutatedampDgenes, including theampDgene of a derepressedC. freundiiisolate, resulted in substantial decreases in ceftazidime MICs (from >256 μg/ml to 12 to 24 μg/ml) for the AmpD−strain, indicating no role for these mutations in derepressed phenotypes. However,ampDtruncation products andampDfrom a partially derepressedP. aeruginosastrain resulted in ceftazidime MICs of >256 μg/ml, indicating a role for these gene modifications in derepressed phenotypes. The use of this model system indicated that alternative mechanisms were involved in the derepressed phenotype observed in strains ofC. freundiiandP. aeruginosa. The alternative mechanism involved in the derepressed phenotype of theC. freundiiisolate was downregulation ofampDtranscription.

Structural and energetic evaluations of substituted 2-(2′-pyridyl)pyrroles were performed through a combination of computational and experimental methods. In conjunction with experimental absorbance and fluorescence studies, the data were analyzed with respect to hydrogen bonding ability, complex formation with alcohols, dimerization, excited state behavior, and potential for proton transfer. Experimental and theoretical evidence show the importance of the pyrrole substituent groups in both structural and spectral properties of the molecules and their complexes. Low temperature NMR experiments and full solution phase DFT optimizations support the formation of a cyclically bridged alcohol complex for the 3,5-dimethyl-2-(2′-pyridyl)pyrrole species with a nearly coplanar ring system, whereas the full DFT optimization of the 3,5-di-tert-butyl-2-(2′-pyridyl)pyrrole:methanol complex shows a break in the planarity of the ring system.

A homologous series of 2-(2′-pyridyl)pyrroles were studied as a possible model system for intermolecular hydrogen bonding interactions in molecules that can act as both hydrogen bond donors and acceptors. Steady state spectroscopic methods were used to assess the importance of intermolecular hydrogen bonding interactions in dilute solutions of 2-(2′-pyridyl)pyrroles in the absence and presence of alcohols. The absorption and fluorescence properties of such solutions were investigated to determine the relevance of such hydrogen bonding interactions in the ground and excited state behavior of the 2-(2′-pyridyl)pyrroles. Over the concentration range studied, no evidence was found for the formation of hydrogen-bonded 2-(2′-pyridyl)pyrrole dimers. However, it was determined that 3,5-dimethyl-2-(2′-pyridyl)pyrrole forms weak (K ∼ 5–12 M−1) 1∶1 hydrogen-bonded complexes with methanol and t-butyl alcohol in the ground state, and 3,5-di-tert-butyl-2-(2′-pyridyl)pyrrole forms both 1∶1 and 1∶2 complexes with the same alcohols. Despite the formation of hydrogen-bonded 2-(2′-pyridyl)pyrrole alcohol complexes, no experimental evidence was found for excited state proton transfer in such complexes.

We report femtosecond pump–probe observations of thermal Na + Kr collisions using a crossed atomic beam arrangement. Though the signal level is very small, a detectable signal is observed which shows the characteristic expected features with respect to intensity, product particle velocity, and pump–probe delay.

High-throughput sequencing of whole genomes is technically already at a high level and is being discussed as a cost-effective alternative to other targeted, analytical procedures for clinical diagnosis of heritable disorders. On the other hand, with whole genome and whole exome sequencing, there is a high likelihood of uncovering secondary findings not associated with the primary aim of the investigation. This article tries to outline the current scientific and technical status of whole genome and whole exome sequencing and of the national and international recommendations concerning the handling of secondary genetic findings which are already available, above all in the research-related context and less so in the clinical context.

Shiga toxin-producing Escherichia coli (STEC) are a common cause for food-borne diarrheal illness outbreaks and sporadic cases. Here, we report the availability of the draft genome sequences of 228 STEC strains representing 32 serotypes with known pulsed-field gel electrophoresis (PFGE) types and epidemiological relationships, as well as 12 strains representing other diarrheagenic E. coli pathotypes.

Femtosecond-laser spectroscopy is used to study the photoionization and photofragmentation of large neutral silicon clusters in a beam. Silicon clusters Sin with sizes up to n≈6000, corresponding to nanoparticles with diameters up to 6 nm, are generated in a laser vaporization source. Nanosecond- and femtosecond-laser ionization are employed to characterize the free silicon nanoparticles. Excitation with intense femtosecond-laser pulses leads to prompt formation of doubly and triply charged Sin clusters. Additionally, strong fragmentation of charged clusters occurs by Coulomb explosion, resulting in high released kinetic energies. Multiply charged atoms up to Si4+ with initial kinetic energies in the range of 500 eV are observed for laser intensities of about 1013 W/cm2. Pump–probe spectroscopy yields decay times of the intermediate resonances of the nanoparticles.

Femtosecond laser spectroscopy was employed to study photoionization and photofragmentation processes of neutral CdTe clusters produced in a laser vaporization source. With time-of-flight mass spectrometry we studied cluster size distributions and identified Te n clusters ( n ⩽30) as well as Cd x Te y hetero-clusters. A strong signal at 4275 amu observed only with fs-laser ionization is tentatively assigned to a Cd 5 Te 29 cluster. First results are reported on the ultrafast dynamics of CdTe-cluster photoionization using pump–probe spectroscopy.

The paper specifies the requirements on a data management system for GMO monitoring by showing which data have to be hold for which purpose. The necessary conditions, plausibilities and dependencies are presented. An Entity Relationship data model is designed conceptionally and logically considering both questionnaires and networks as data sources and common statistical software packages (SPSS, SAS). The physical implementation of this data model will be described.

A new approach for the detection of chromosome deletion 22q11.2 in interphase nuclei from buccal mucosa cells obtained by a non-invasive procedure is decribed. FISH analysis has been performed on samples from a group of 101 patients that presented consecutively for speech therapy and/or surgical correction of cleft palate. A normal result has been obtained in 98 patients; a deletion 22q11.2 was present in three patients (2.8%) with cleft palate.

Based on the compilation of medical opinions delivered by a medical genetic expert between 2002 and 2010, solicited by private health insurance companies in Germany, an analysis of the main issues raised was made to identify the information needs of company employees with respect to human and medical genetics. The findings are discussed and recommendations for improvement and further training are suggested.

Line-side interoperability of colored 100G transponders in DWDM systems between two different vendors will become a reality in the near future. With modern modulation formats (phase, polarization and post processing) and existing standards, optical interface technologies can deliver reliable transmission over more than 600km. That is the sweet spot for most of the metro and regional deployments.

We investigate the use of integrated packet/circuit/wavelength switches in next-generation optical core networks and compare different node architectures for a 46 node, 25,840 route-km US network.