484 research outputs found
The effect of precursor structure on porous carbons produced by iron-catalyzed graphitization of biomass
This paper reports a systematic study into the effect of different biomass-derived precursors on the structure and porosity of carbons prepared via catalytic graphitization. Glucose, starch and cellulose are combined with iron nitrate and heated under a nitrogen atmosphere to produce Fe3C nanoparticles, which catalyze the conversion of amorphous carbon to graphitic nanostructures. The choice of organic precursor provides a means of controlling the catalyst particle size, which has a direct effect on the porosity of the material. Cellulose and glucose produce mesoporous carbons, while starch produces a mixture of micro- and mesopores under the same conditions and proceeds via a much slower graphitization step, generating a mixture of graphitic nanostructures and turbostratic carbon. Porous carbons are critical to energy applications such as batteries and electrocatalytic processes. For these applications, a simple and sustainable route to those carbons is essential. Therefore, the ability to control the precise structure of a biomass-derived carbon simply through the choice of precursor will enable the production of a new generation of energy materials
DipyrrinatoβIridium(III) Complexes for Application in Photodynamic Therapy and Antimicrobial Photodynamic Inactivation
The generation of bio-targetable photosensitizers is of utmost importance to the emerging field of photodynamic therapy and antimicrobial (photo-)therapy. A synthetic strategy is presented in which chelating dipyrrin moieties are used to enhance the known photoactivity of iridium(III) metal complexes. Formed complexes can thus be functionalized in a facile manner with a range of targeting groups at their chemically active reaction sites. Dipyrrins with N- and O-substituents afforded (dipy)iridium(III) complexes via complexation with the respective Cp*-iridium(III) and ppy-iridium(III) precursors (dipy=dipyrrinato, Cp*=pentamethyl-eta(5)-cyclopentadienyl, ppy=2-phenylpyridyl). Similarly, electron-deficient [Ir-III(dipy)(ppy)(2)] complexes could be used for post-functionalization, forming alkenyl, alkynyl and glyco-appended iridium(III) complexes. The phototoxic activity of these complexes has been assessed in cellular and bacterial assays with and without light; the [Ir-III(Cl)(Cp*)(dipy)] complexes and the glyco-substituted iridium(III) complexes showing particular promise as photomedicine candidates. Representative crystal structures of the complexes are also presented
Development of an approximate method for quantum optical models and their pseudo-Hermicity
An approximate method is suggested to obtain analytical expressions for the
eigenvalues and eigenfunctions of the some quantum optical models. The method
is based on the Lie-type transformation of the Hamiltonians. In a particular
case it is demonstrated that Jahn-Teller Hamiltonian can
easily be solved within the framework of the suggested approximation. The
method presented here is conceptually simple and can easily be extended to the
other quantum optical models. We also show that for a purely imaginary coupling
the Hamiltonian becomes non-Hermitian but -symmetric. Possible generalization of this approach is outlined.Comment: Paper prepared fo the "3rd International Workshop on Pseudo-Hermitian
Hamiltonians in Quantum Physics" June 2005 Istanbul. To be published in
Czechoslovak Journal of Physic
Π€ΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ Π΄Π²ΠΎΠΉΠ½ΡΡ ΡΠ²ΡΠ·Π΅ΠΉ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΠ΅ΡΠΌΠΎΠΊΠ°ΡΠ°Π»ΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π΄Π΅Π³ΠΈΠ΄ΡΠ°ΡΠ°ΡΠΈΠΈ ΠΏΠΎΠ»ΠΈΠ²ΠΈΠ½ΠΈΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠΈΡΡΠ°
The formation of a conjugated bond system in the heat treatment of polyvinyl alcohol films with the addition of hydrochloric acid as an acid catalyst for thermal dehydration in the range of 80-150 Β°C has been studied on the base of electronic spectra. It is established that the fine structure in the absorption spectra in the 282-443 nm region is associated with electronic transitions in polyconjugated chains with the number of carbon atoms from 8 to 18, with the exception of the bands at 310 and 342 nm; only one peak at 361 nm of four lines in the wide band at 352-380 nm is associated with optical transitions in the polyconjugated chain containing 12 carbon atoms. It is shown that the long-wave boundary of the spectrum is due to electronic transitions in polyconjugated chains of the largest sizes; the maximum size of such chains can be determined by comparing the dependence of the Tauc band gap and the energy of the optical transitions as an inverse function of the number of carbon atoms in the conjugate chain. Since the typical sizes of such poly-conjugation chains are hundreds of carbon atoms (about 300 atoms in films heated at 100 Β°C), these chains can be considered as trans-polyacetylene nanoclusters incorporated into a polyvinyl alcohol matrix.ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΡ
ΡΠΏΠ΅ΠΊΡΡΠΎΠ² ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ ΠΈΠ·ΡΡΠ΅Π½ΠΎ ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ ΡΠΎΠΏΡΡΠΆΠ΅Π½Π½ΡΡ
ΡΠ²ΡΠ·Π΅ΠΉ ΠΏΡΠΈ ΡΠ΅ΡΠΌΠΎΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠ΅ ΠΏΠ»Π΅Π½ΠΎΠΊ ΠΏΠΎΠ»ΠΈΠ²ΠΈΠ½ΠΈΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠΈΡΡΠ° Π² ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π΅ 80-150 Β°Π‘ Ρ Π΄ΠΎΠ±Π°Π²ΠΊΠΎΠΉ Ρ
Π»ΠΎΡΠΈΡΡΠΎΠ²ΠΎΠ΄ΠΎΡΠΎΠ΄Π½ΠΎΠΉ ΠΊΠΈΡΠ»ΠΎΡΡ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΊΠΈΡΠ»ΠΎΡΠ½ΠΎΠ³ΠΎ ΠΊΠ°ΡΠ°Π»ΠΈΠ·Π°ΡΠΎΡΠ° ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ Π΄Π΅Π³ΠΈΠ΄ΡΠ°ΡΠ°ΡΠΈΠΈ. Π£ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΡΠΎ ΡΠΎΠ½ΠΊΠ°Ρ ΡΡΡΡΠΊΡΡΡΠ° Π² ΡΠΏΠ΅ΠΊΡΡΠ°Ρ
ΠΏΠΎΠ³Π»ΠΎΡΠ΅Π½ΠΈΡ Π² ΠΎΠ±Π»Π°ΡΡΠΈ 282-443 Π½ΠΌ ΡΠ²ΡΠ·Π°Π½Π° Ρ ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΠΌΠΈ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Π°ΠΌΠΈ Π² ΡΠ΅ΠΏΡΡ
ΠΏΠΎΠ»ΠΈΡΠΎΠΏΡΡΠΆΠ΅Π½ΠΈΡ Ρ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²ΠΎΠΌ Π°ΡΠΎΠΌΠΎΠ² ΡΠ³Π»Π΅ΡΠΎΠ΄Π° ΠΎΡ 8 Π΄ΠΎ 18, Π·Π° ΠΈΡΠΊΠ»ΡΡΠ΅Π½ΠΈΠ΅ΠΌ ΠΏΠΎΠ»ΠΎΡ ΠΏΡΠΈ 310 ΠΈ 342 Π½ΠΌ ΠΈ ΡΡΠ΅Ρ
Π»ΠΈΠ½ΠΈΠΉ Π² ΡΠΎΡΡΠ°Π²Π΅ ΡΠΈΡΠΎΠΊΠΎΠΉ ΠΏΠΎΠ»ΠΎΡΡ ΠΏΡΠΈ 352-380 Π½ΠΌ, ΡΠΎΠ΄Π΅ΡΠΆΠ°ΡΠ΅Π΅ ΡΠ°ΠΊΠΆΠ΅ ΠΏΠΈΠΊ ΠΏΡΠΈ 361 Π½ΠΌ, ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π½ΡΠΉ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Π°ΠΌΠΈ Π² ΡΠ΅ΠΏΠΈ ΠΏΠΎΠ»ΠΈΡΠΎΠΏΡΡΠΆΠ΅Π½ΠΈΡ ΠΈΠ· 12 Π°ΡΠΎΠΌΠΎΠ² ΡΠ³Π»Π΅ΡΠΎΠ΄Π°. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ Π΄Π»ΠΈΠ½Π½ΠΎΠ²ΠΎΠ»Π½ΠΎΠ²Π°Ρ Π³ΡΠ°Π½ΠΈΡΠ° ΡΠΏΠ΅ΠΊΡΡΠ° ΠΎΠ±ΡΡΠ»ΠΎΠ²Π»Π΅Π½Π° ΡΠ»Π΅ΠΊΡΡΠΎΠ½Π½ΡΠΌΠΈ ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄Π°ΠΌΠΈ Π² ΡΠ΅ΠΏΡΡ
ΠΏΠΎΠ»ΠΈΡΠΎΠΏΡΡΠΆΠ΅Π½ΠΈΡ Π½Π°ΠΈΠ±ΠΎΠ»ΡΡΠΈΡ
ΡΠ°Π·ΠΌΠ΅ΡΠΎΠ²; ΠΌΠ°ΠΊΡΠΈΠΌΠ°Π»ΡΠ½ΡΠΉ ΡΠ°Π·ΠΌΠ΅Ρ ΡΠ°ΠΊΠΈΡ
ΡΠ΅ΠΏΠ΅ΠΉ ΠΌΠΎΠΆΠ½ΠΎ ΠΎΠΏΡΠ΅Π΄Π΅Π»ΠΈΡΡ ΠΈΠ· ΡΠΎΠΏΠΎΡΡΠ°Π²Π»Π΅Π½ΠΈΡ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΡΠΈΡΠΈΠ½Ρ Π·Π°ΠΏΡΠ΅ΡΠ΅Π½Π½ΠΎΠΉ Π·ΠΎΠ½Ρ Π’Π°ΡΡΠ° ΠΈ ΡΠ½Π΅ΡΠ³ΠΈΠΈ ΠΎΠΏΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΏΠ΅ΡΠ΅Ρ
ΠΎΠ΄ΠΎΠ² ΠΊΠ°ΠΊ ΠΎΠ±ΡΠ°ΡΠ½ΠΎΠΉ ΡΡΠ½ΠΊΡΠΈΠΈ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π° Π°ΡΠΎΠΌΠΎΠ² ΡΠ³Π»Π΅ΡΠΎΠ΄Π° Π² ΡΠ΅ΠΏΠΈ ΡΠΎΠΏΡΡΠΆΠ΅Π½ΠΈΡ. ΠΠΎΡΠΊΠΎΠ»ΡΠΊΡ ΡΠΈΠΏΠΈΡΠ½ΡΠ΅ ΡΠ°Π·ΠΌΠ΅ΡΡ ΡΠ°ΠΊΠΈΡ
ΡΠ΅ΠΏΠ΅ΠΉ ΠΏΠΎΠ»ΠΈΡΠΎΠΏΡΡΠΆΠ΅Π½ΠΈΡ ΡΠΎΡΡΠ°Π²Π»ΡΡΡ ΡΠΎΡΠ½ΠΈ Π°ΡΠΎΠΌΠΎΠ² ΡΠ³Π»Π΅ΡΠΎΠ΄Π° (ΠΎΠΊΠΎΠ»ΠΎ 300 Π°ΡΠΎΠΌΠΎΠ² Π² ΠΏΠ»Π΅Π½ΠΊΠ°Ρ
, ΠΏΡΠΎΠ³ΡΠ΅ΡΡΡ
ΠΏΡΠΈ 100 Β°Π‘), ΠΈΡ
ΠΌΠΎΠΆΠ½ΠΎ ΡΠ°ΡΡΠΌΠ°ΡΡΠΈΠ²Π°ΡΡ ΠΊΠ°ΠΊ Π½Π°Π½ΠΎΠΊΠ»Π°ΡΡΠ΅ΡΡ ΡΡΠ°Π½ΡΠΏΠΎΠ»ΠΈΠ°ΡΠ΅ΡΠΈΠ»Π΅Π½Π°, ΠΈΠ½ΠΊΠΎΡΠΏΠΎΡΠΈΡΠΎΠ²Π°Π½Π½ΡΠ΅ Π² ΠΌΠ°ΡΡΠΈΡΡ ΠΏΠΎΠ»ΠΈΠ²ΠΈΠ½ΠΈΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΡΠΏΠΈΡΡΠ°
Research Priorities for FCTC Articles 20, 21, and 22: Surveillance/Evaluation and Information Exchange
Framework Convention on Tobacco Control (FCTC) Articles 20, 21, and 22 call for strong monitoring and reporting of tobacco use and factors influencing use and disease (Articles 20 and 21) and for collaboration among the Parties and relevant organizations to share resources, knowledge, and expertise on all relevant tobacco control strategies (Article 22)
The Impact II, a Very High-Resolution Quadrupole Time-of-Flight Instrument (QTOF) for Deep Shotgun Proteomics
Hybrid quadrupole time-of-flight (QTOF) mass spectrometry is one of the two major principles used in proteomics. Although based on simple fundamentals, it has over the last decades greatly evolved in terms of achievable resolution, mass accuracy, and dynamic range. The Bruker impact platform of QTOF instruments takes advantage of these developments and here we develop and evaluate the impact II for shotgun proteomics applications. Adaption of our heated liquid chromatography system achieved very narrow peptide elution peaks. The impact II is equipped with a new collision cell with both axial and radial ion ejection, more than doubling ion extraction at high tandem MS frequencies. The new reflectron and detector improve resolving power compared with the previous model up to 80%, i.e. to 40,000 at m/z 1222. We analyzed the ion current from the inlet capillary and found very high transmission (>80%) up to the collision cell. Simulation and measurement indicated 60% transfer into the flight tube. We adapted MaxQuant for QTOF data, improving absolute average mass deviations to better than 1.45 ppm. More than 4800 proteins can be identified in a single run of HeLa digest in a 90 min gradient. The workflow achieved high technical reproducibility (R2 > 0.99) and accurate fold change determination in spike-in experiments in complex mixtures. Using label-free quantification we rapidly quantified haploid against diploid yeast and characterized overall proteome differences in mouse cell lines originating from different tissues. Finally, after high pH reversed-phase fractionation we identified 9515 proteins in a triplicate measurement of HeLa peptide mixture and 11,257 proteins in single measurements of cerebellum-the highest proteome coverage reported with a QTOF instrument so far
In search of the origins and enduring impact of agile software development
The Agile Manifesto is a philosophical touchpoint for all agile
software development (ASD) methods. We examine the manifesto
and some of its associated agile methods in an effort to identify
the major impacts of ASD. We have encountered some difficulty
in delineating agile and non-agile software processes, which is
partially the result of terminological confusion. It is clear from the
volume of published research that ASD has made a significant
contribution, and we have identified two lasting and important
impacts. Firstly, the reduction in iteration durations and secondly,
the push for reduced levels of documentation (especially in
relation to software requirements). Other aspects of the Agile
Manifesto may not have exerted a significant impact; for example,
the use of tooling to automate processes has become central to
continuous software engineering (CSE) and may not be wholly
congruent with the manifesto. Furthermore, many organisations
may still rely on business contracts despite calls in the manifesto
for greater levels of informal customer collaboration
Investigation of the Dynamic Behaviour of H2 and D2 in a Kinetic Quantum Sieving System
Porous organic cages (POCs) are nanoporous materials composed of discrete molecular units that have uniformly distributed functional pores. The intrinsic porosity of these structures can be tuned accurately at the nanoscale by altering the size of the porous molecules, particularly to an optimal size of 3.6 Γ
, to harness the kinetic quantum sieving effect. Previous research on POCs for isotope separation has predominantly centered on differences in the quantities of adsorbed isotopes. However, nuclear quantum effects also contribute significantly to the dynamics of the sorption process, offering additional opportunities for separating H2 and D2 at practical operational temperatures. In this study, our investigations into H2 and D2 sorption on POC samples revealed a higher uptake of D2 compared to that of H2 under identical conditions. We employed quasi-elastic neutron scattering to study the diffusion processes of D2 and H2 in the POCs across various temperature and pressure ranges. Additionally, neutron Compton scattering was utilized to measure the values of the nuclear zero-point energy of individual isotopic species in D2 and H2. The results indicate that the diffusion coefficient of D2 is approximately one-sixth that of H2 in the POC due to the nuclear quantum effect. Furthermore, the results reveal that at 77 K, D2 has longer residence times compared to H2 when moving from pore to pore. Consequently, using the kinetic difference of H2 and D2 in a porous POC system enables hydrogen isotope separation using a temperature or pressure swing system at around liquid nitrogen temperatures
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