Grazing-incidence synchrotron radiation diffraction studies on irradiated Ce-doped and pristine Y-stabilized ZrO2 at the Rossendorf beamline

In this work, Ce-doped yttria-stabilized zirconia (YSZ) and pure YSZ phases were subjected to irradiation with 14 MeV Au ions. Irradiation studies were performed to simulate long-term structural and microstructural damage due to self-irradiation in YSZ phases hosting alpha-active radioactive species. It was found that both the Ce-doped YSZ and the YSZ phases had a reasonable tolerance to irradiation at high ion fluences and the bulk crystallinity was well preserved. Nevertheless, local microstrain increased in all compounds under study after irradiation, with the Ce-doped phases being less affected than pure YSZ. Doping with cerium ions increased the microstructural stability of YSZ phases through a possible reduction in the mobility of oxygen atoms, which limits the formation of structural defects. Doping of YSZ with tetravalent actinide elements is expected to have a similar effect. Thus, YSZ phases are promising for the safe long-term storage of radioactive elements. Using synchrotron radiation diffraction, measurements of the thin irradiated layers of the Ce-YSZ and YSZ samples were performed in grazing incidence (GI) mode. A corresponding module for measurements in GI mode was developed at the Rossendorf Beamline and relevant technical details for sample alignment and data collection are also presented.

Temporal Structures in Positron Spectra and Charge-Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic positron fluxes in the rigidity range from 1.00 to 41.9 GV based on 3.4×10^{6} positrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The positron fluxes show distinctly different time variations from the electron fluxes at short and long timescales. A hysteresis between the electron fluxes and the positron fluxes is observed with a significance greater than 5σ at rigidities below 8.5 GV. On the contrary, the positron fluxes and the proton fluxes show similar time variation. Remarkably, we found that positron fluxes are modulated more than proton fluxes with a significance greater than 5σ for rigidities below 7 GV. These continuous daily positron fluxes, together with AMS daily electron, proton, and helium fluxes over an 11-year solar cycle, provide unique input to the understanding of both the charge-sign and mass dependencies of cosmic rays in the heliosphere.

Anhydrous Aluminum Carbonates and Isostructural Compounds

We synthesized the inorganic anhydrous aluminum carbonates Al2[C2O5][CO3]2 and Al2[CO3]3 by reacting Al2O3 with CO2 at high pressures and temperatures and characterized them by Raman spectroscopy. Their structures were solved by X-ray diffraction. Al2[CO3]3 forms at around 24-28 GPa, while Al2[C2O5][CO3]2 forms above 38(3) GPa. The distinguishing feature of the new Al2[C2O5][CO3]2-structure type is the presence of pyrocarbonate [C2O5]2--groups, trigonal [CO3]2─groups, and octahedrally coordinated trivalent cations. Al2[CO3]3 has isolated [CO3]2--groups. Both Al-carbonates can be recovered under ambient conditions. Density functional theory calculations predict that CO2 will react with Fe2O3, Ti2O3, Ga2O3, In2O3, and MgSiO3 at high pressures to form compounds which are isostructural to Al2[C2O5][CO3]2. MgSi[C2O5][CO3]2 is predicted to be stable at pressures relative to abundant mantle minerals in the presence of CO2. This structure type allows the incorporation of four elements (Mg, Si, Fe, and Al) abundant in the Earth's mantle in octahedral coordination and provides an alternative phase with novel carbon speciation for carbon storage in the deep Earth.

Properties of Cosmic-Ray Sulfur and Determination of the Composition of Primary Cosmic-Ray Carbon, Neon, Magnesium, and Sulfur: Ten-Year Results from the Alpha Magnetic Spectrometer

We report the properties of primary cosmic-ray sulfur (S) in the rigidity range 2.15 GV to 3.0 TV based on 0.38×10^{6} sulfur nuclei collected by the Alpha Magnetic Spectrometer experiment (AMS). We observed that above 90 GV the rigidity dependence of the S flux is identical to the rigidity dependence of Ne-Mg-Si fluxes, which is different from the rigidity dependence of the He-C-O-Fe fluxes. We found that, similar to N, Na, and Al cosmic rays, over the entire rigidity range, the traditional primary cosmic rays S, Ne, Mg, and C all have sizeable secondary components, and the S, Ne, and Mg fluxes are well described by the weighted sum of the primary silicon flux and the secondary fluorine flux, and the C flux is well described by the weighted sum of the primary oxygen flux and the secondary boron flux. The primary and secondary contributions of the traditional primary cosmic-ray fluxes of C, Ne, Mg, and S (even Z elements) are distinctly different from the primary and secondary contributions of the N, Na, and Al (odd Z elements) fluxes. The abundance ratio at the source for S/Si is 0.167±0.006, for Ne/Si is 0.833±0.025, for Mg/Si is 0.994±0.029, and for C/O is 0.836±0.025. These values are determined independent of cosmic-ray propagation.

Deconvoluting Cr states in Cr-doped UO2 nuclear fuels via bulk and single crystal spectroscopic studies

Cr-doped UO₂ is a leading accident tolerant nuclear fuel where the complexity of Cr chemical states in the bulk material has prevented acquisition of an unequivocal understanding of the redox chemistry and mechanism for incorporation of Cr in the UO₂ matrix. To resolve this, we have used electron paramagnetic resonance, high energy resolution fluorescence detection X-ray absorption near energy structure and extended X-ray absorption fine structure spectroscopic measurements to examine Cr-doped UO₂ single crystal grains and bulk material. Ambient condition measurements of the single crystal grains, which have been mechanically extracted from bulk material, indicated Cr is incorporated substitutionally for U⁺⁴ in the fluorite lattice as Cr⁺³ with formation of additional oxygen vacancies. Bulk material measurements reveal the complexity of Cr states, where metallic Cr (Cr⁰) and oxide related Cr⁺² and Cr⁺³₂O₃ were identified and attributed to grain boundary species and precipitates, with concurrent (Cr⁺³_xU⁺⁴_1-x)O_2-0.5x lattice matrix incorporation. The deconvolution of chemical states via crystal vs. powder measurements enables the understanding of discrepancies in literature whilst providing valuable direction for safe continued use of Cr-doped UO₂ fuels for nuclear energy generation.

Temporal Structures in Electron Spectra and Charge Sign Effects in Galactic Cosmic Rays

We present the precision measurements of 11 years of daily cosmic electron fluxes in the rigidity interval from 1.00 to 41.9 GV based on 2.0×10^{8} electrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The electron fluxes exhibit variations on multiple timescales. Recurrent electron flux variations with periods of 27 days, 13.5 days, and 9 days are observed. We find that the electron fluxes show distinctly different time variations from the proton fluxes. Remarkably, a hysteresis between the electron flux and the proton flux is observed with a significance of greater than 6σ at rigidities below 8.5 GV. Furthermore, significant structures in the electron-proton hysteresis are observed corresponding to sharp structures in both fluxes. This continuous daily electron data provide unique input to the understanding of the charge sign dependence of cosmic rays over an 11-year solar cycle.

School-based sexuality Education in Europe and Central Asia

Introduction

In 2016, the BZgA and the European Network of the International Planned Parenthood Federation initiated an extensive survey regarding the development and current status of sexuality education (SE) in Europe and Central Asia, which included 25 selected countries of the European WHO Region. Since 2000, remarkable progress has been made in the region in developing and integrating SE curricula in school settings. The majority of the surveyed countries teach basic elements of SE in schools. Yet, in about half of the countries, there is still some reticence in understanding the benefits of SE for the health and well-being of young people. In countries with fully developed comprehensive SE programmes, the school is the main source of information on sexuality for young people. In the other countries young people tend to rely on information from friends or peers and the internet. The findings also showed a gap in teacher training on sexuality education.

Methods

The Survey included a detailed questionnaire, among member associations of IPPF EN and government agencies responsible for SE. A random sample was drawn from the 50 states of the region which is considered representative for the entire region. All 25 IPPF EN members and 16 of the 25 government agencies responded.

Results and discussion

Remarkable progress has been made in developing and integrating SE in formal school curricula. In 11 of the 21 countries, SE is a mandatory teaching subject, and in six additional countries it is partly mandatory. In four additional countries it is optional. Despite the progress, there are still shortcomings and gaps in providing the full spectrum of SE.

Conclusions

If provided, SE tends to focus primarily on the biological aspects and prevention of HIV/STIs and unwanted pregnancy. There is a need to broaden the spectrum of topics that are addressed to include gender equality, sexuality, violence and sexual abuse, human rights and empowerment.

Cenozoic evolution of deep ocean temperature from clumped isotope thermometry

Characterizing past climate states is crucial for understanding the future consequences of ongoing greenhouse gas emissions. Here, we revisit the benchmark time series for deep ocean temperature across the past 65 million years using clumped isotope thermometry. Our temperature estimates from the deep Atlantic Ocean are overall much warmer compared with oxygen isotope-based reconstructions, highlighting the likely influence of changes in deep ocean pH and/or seawater oxygen isotope composition on classical oxygen isotope records of the Cenozoic. In addition, our data reveal previously unrecognized large swings in deep ocean temperature during early Eocene acute greenhouse warmth. Our results call for a reassessment of the Cenozoic history of ocean temperatures to achieve a more accurate understanding of the nature of climatic responses to tectonic events and variable greenhouse forcing.

Properties of Daily Helium Fluxes

We present the precision measurement of 2824 daily helium fluxes in cosmic rays from May 20, 2011 to October 29, 2019 in the rigidity interval from 1.71 to 100 GV based on 7.6×10^{8} helium nuclei collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The helium flux and the helium to proton flux ratio exhibit variations on multiple timescales. In nearly all the time intervals from 2014 to 2018, we observed recurrent helium flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. In the entire time period, we found that below ∼7  GV the helium flux exhibits larger time variations than the proton flux, and above ∼7  GV the helium to proton flux ratio is time independent. Remarkably, below 2.4 GV a hysteresis between the helium to proton flux ratio and the helium flux was observed at greater than the 7σ level. This shows that at low rigidity the modulation of the helium to proton flux ratio is different before and after the solar maximum in 2014.

Formation Mechanism of a Nano‐Ring of Bismuth Cations and Mono‐Lacunary Keggin‐Type Phosphomolybdate

A new hetero‐bimetallic polyoxometalate (POM) nano‐ring was synthesized in a one‐pot procedure. The structure consists of tetrameric units containing four bismuth‐substituted monolacunary Keggin anions including distorted [BiO₈] cubes. The nano‐ring is formed via self‐assembly from metal precursors in aqueous acidic medium. The compound (NH₄)₁₆[(BiPMo₁₁O₃₉)₄] ⋅ 22 H₂O; (P₄Bi₄Mo₄₄) was characterized by single‐crystal X‐ray diffraction, extended X‐ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix‐assisted laser desorption/ionisation‐time of flight mass spectrometry (MALDI‐TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG‐DSC‐MS). The formation of the nano‐ring in solution was studied by time‐resolved in situ small‐ and wide‐angle X‐ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L₃ edge indicating a two‐step process consisting of condensation of Mo‐anions and formation of Bi−Mo‐units followed by a rapid self‐assembly to yield the final tetrameric ring structure.

Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV

We present the precision measurement of the daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total of 2824 days or 114 Bartels rotations) in the rigidity interval from 1 to 100 GV based on 5.5×10^{9} protons collected with the Alpha Magnetic Spectrometer aboard the International Space Station. The proton fluxes exhibit variations on multiple timescales. From 2014 to 2018, we observed recurrent flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. The rigidity dependence of the 27-day periodicity is different from the rigidity dependences of 9-day and 13.5-day periods. Unexpectedly, the strength of 9-day and 13.5-day periodicities increases with increasing rigidities up to ∼10  GV and ∼20  GV, respectively. Then the strength of the periodicities decreases with increasing rigidity up to 100 GV.

Erratum: Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen [Phys. Rev. Lett. 127, 021101 (2021)]

This corrects the article DOI: 10.1103/PhysRevLett.127.021101.

Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen

We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na/Si and Al/Si abundance ratios at the source, 0.036±0.003 for Na/Si and 0.103±0.004 for Al/Si, are determined independent of cosmic ray propagation.

Properties of Heavy Secondary Fluorine Cosmic Rays: Results from the Alpha Magnetic Spectrometer

Precise knowledge of the charge and rigidity dependence of the secondary cosmic ray fluxes and the secondary-to-primary flux ratios is essential in the understanding of cosmic ray propagation. We report the properties of heavy secondary cosmic ray fluorine F in the rigidity R range 2.15 GV to 2.9 TV based on 0.29 million events collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The fluorine spectrum deviates from a single power law above 200 GV. The heavier secondary-to-primary F/Si flux ratio rigidity dependence is distinctly different from the lighter B/O (or B/C) rigidity dependence. In particular, above 10 GV, the F/Si/B/O ratio can be described by a power law R^{δ} with δ=0.052±0.007. This shows that the propagation properties of heavy cosmic rays, from F to Si, are different from those of light cosmic rays, from He to O, and that the secondary cosmic rays have two classes.

Bridging experiment and theory: enhancing the electrical conductivities of soft-templated niobium-doped mesoporous titania films

Theoretical calculations suggest a strong dependence of electrical conductivity and doping concentration in transition-metal doped titania. Herein, we present a combined theoretical and experimental approach for the prediction of relative phase stability and electrical conductivity in niobium-doped titania as model system. Our method paves the way towards the development of materials with improved electrical properties.

Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10^{6} iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. This shows that unexpectedly Fe and He, C, and O belong to the same class of primary cosmic rays which is different from the primary cosmic rays Ne, Mg, and Si class.

Properties of Neon, Magnesium, and Silicon Primary Cosmic Rays Results from the Alpha Magnetic Spectrometer

We report the observation of new properties of primary cosmic rays, neon (Ne), magnesium (Mg), and silicon (Si), measured in the rigidity range 2.15 GV to 3.0 TV with 1.8×10^{6}  Ne, 2.2×10^{6}  Mg, and 1.6×10^{6}  Si nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. The Ne and Mg spectra have identical rigidity dependence above 3.65 GV. The three spectra have identical rigidity dependence above 86.5 GV, deviate from a single power law above 200 GV, and harden in an identical way. Unexpectedly, above 86.5 GV the rigidity dependence of primary cosmic rays Ne, Mg, and Si spectra is different from the rigidity dependence of primary cosmic rays He, C, and O. This shows that the Ne, Mg, and Si and He, C, and O are two different classes of primary cosmic rays.

Investigating the role of reducing agents on mechanosynthesis of Au nanoparticles

The influence of reducing agents on the mechanochemical synthesis of Au nanoparticles differ significantly from analogous solution syntheses. Environmentally benign mechanochemical syntheses of metal nanoparticles therefore require dedicated studies.

Microstrain distribution mapping on CuInSe2 thin films by means of electron backscatter diffraction, X-ray diffraction, and Raman microspectroscopy

The investigation of the microstructure in functional, polycrystalline thin films is an important contribution to the enhanced understanding of structure-property relationships in corresponding devices. Linear and planar defects within individual grains may affect substantially the performance of the device. These defects are closely related to strain distributions. The present work compares electron and X-ray diffraction as well as Raman microspectroscopy, which provide access to microstrain distributions within individual grains. CuInSe2 thin films for solar cells are used as a model system. High-resolution electron backscatter diffraction and X-ray microdiffraction as well as Raman microspectroscopy were applied for this comparison. Consistently, microstrain values were determined of the order of 10(-4) by these three techniques. However, only electron backscatter diffraction, X-ray microdiffraction exhibit sensitivities appropriate for mapping local strain changes at the submicrometer level within individual grains in polycrystalline materials.

High-throughput evaluation of olefin copolymer composition by means of attenuated total reflection Fourier tranform infrared spectroscopy

As a consequence of developing fully automated reactors for organic and organometallic synthesis and polymerizations combined with rapid on-line analysis, databases, and data mining, the analysis of polymers with respect to composition and properties has been speeded up. High-throughput evaluation of olefin copolymers requires fast measurements and high accuracy without tedious sample preparation such as pressing KBr pellets. This has been achieved by using attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR spectroscopy) in conjunction with multivariate calibration in order to determine the composition of olefin copolymers such as ethene/propene, ethene/1-hexene and ethene/1-octene copolymers.

Changes in the photosynthetic apparatus of diatoms in response to low and high light intensities

The centric diatom Cyclotella cryptica and two strains of the pennate diatom Phaeodactylum tricornutum were grown under low and high light intensities (300 lux and 3,000 lux) over 4-6 weeks. Growth was monitored by repetitive cell count. The culture media were replaced weekly to avoid morphological and biochemical alterations caused by nutrient depletion. The ultrastructure of the cells was examined by transmission electron microscopy. Alterations in the light-harvesting antenna systems were investigated by Western immunoblotting. Both diatoms reduced the plastid area, i.e. decreased the amount of thylakoid lamellae, under high light intensity. The thylakoids still ran in groups of three with parallel orientation within the chloroplasts. The girdle band lamellae were not affected. The amounts of storage compounds and vacuoles increased. SDS-PAGE of total cell protein followed by Western immunoblotting with antisera directed against subunits of the light-harvesting antenna systems of C. cryptica (cc-antiserum) and the cryptophyte Cryptomonas maculata (cmac-antiserum) revealed that both diatoms reduced the amount of antenna polypeptides under increased light intensity. The cc-antiserum immunodecorated two bands with relative molecular masses (Mr) of 18,000 and 22,000 in C. cryptica. Both decreased under high light conditions to 67.2 +/- 6.1%. Five to seven bands in the Mr range of 14,000-27,000 were recognized in P. tricornutum. They decreased to 83 +/- 5.3%. Furthermore, the immunolabeling pattern for both strains differed under the two light regimes. The cmac-antiserum immunodecorated two polypeptides with Mr of 24,000 and 23,000 in C. cryptica, while both strains of P. tricornutum had five polypeptides in the Mr range of 14,000-24,000 that showed some differences in staining intensities between the two strains and in response to the light intensity applied.

The gene family coding for the light-harvesting polypeptides of Photosystem I of the red alga Galdieria sulphuraria

Recently [Marquardt et al. (2000) Gene 255: 257-265], we isolated a gene encoding a polypeptide of the light-harvesting complex of Photosystem I (LHC I) of the red alga Galdieria sulphuraria. By screening a G. sulphuraria cDNA library with a DNA probe coding for the conserved first transmembrane helix of this protein we isolated four additional genes coding for LHC I polypeptides. The deduced preproteins had calculated molecular masses of 24.6-25.6 kDa and isoelectric points of 8.09-9.82. N-terminal sequencing of a LHC I polypeptide isolated by gel electrophoresis allowed us to determine the cleavage site of the transit peptide of one of the deduced polypeptides. The mature protein has a calculated molecular mass of 20.6 kDa and an isoelectric point of 7.76. The genes were amplified from nuclear G. sulphuraria DNA by polymerase chain reaction (PCR) using oligonucleotides annealing in the regions of the start and stop codons as primers. All genomic sequences were 80-300 base pairs longer than the PCR products obtained from the respective cDNA clones, pointing to the existence of 1-5 introns per gene. The G. sulphuraria genes form a homogeneous gene family with overall pairwise amino acid identities of 46.0-56.6%. Homology to two diatom, one cryptophytic and two higher plant light-harvesting polypeptides was lower with pairwise identities of 21.1-34.1%. Only one diatom polypeptide showed a higher degree of identity of up to -39.3%.

Intron-exon structure and gene copy number of a gene encoding for a membrane-intrinsic light-harvesting polypeptide of the red alga Galdieria sulphuraria

Genes for light-harvesting proteins (lhc genes) of higher plants are well examined. However, little is known about the corresponding genes of algae, although this knowledge might give valuable information about the evolution of photosynthetic antennae. In the case of rhodophytes only two cDNA sequences from a single organism, Porphyridium cruentum, have been published. Here we describe an additional sequence from another species, the thermo-acidophilic red alga Galdieria sulphuraria. For the first time also a genomic sequence for a red algal lhc gene is presented. From a cDNA library of G. sulphuraria we isolated a clone containing an open reading frame for a protein of 302 amino acids with a deduced molecular mass of 33.86kDa. It shares major structural features with eukaryotic light-harvesting polypeptides. A proposed cleavage site between transit peptide and mature protein gives rise to a transit peptide of 119 amino acids and a mature protein of 183 residues. Hydropathy analysis suggests that the mature protein consists of three transmembrane helices. Several amino acid residues supposed to bind chlorophyll a and chlorophyll b in higher plants are conserved. The protein shows up to 69% identity and 81% similarity to the Porphyridium polypeptides in the transmembrane helices 1 and 3. Using oligonucleotides annealing in the regions of the start and stop codons of the gene as primers, a DNA sequence was amplified from nuclear G. sulphuraria DNA by PCR. Compared with the cDNA clone, this sequence contains five additional intervening DNA strings of 50-74bp length. Four of them show typical features of spliceosomal introns with GT-AG borders, and the fifth differs by starting with GC. Three of the supposed introns are located in similar positions as introns of higher plant light-harvesting proteins. Southern blotting and hybridization experiments indicate that G. sulphuraria contains at least three copies of this gene.

Ultrastructure of Acaryochloris marina, an oxyphotobacterium containing mainly chlorophyll d

We present a detailed investigation of the ultrastructure of the chlorophyll a/d-containing unicellular oxyphotobacterium Acaryochloris marina, combining light and transmission electron microscopy and showing freeze fractures of this organism for the first time. The cells were 1.8-2.1 microm x 1.5-1.7 microm in size. The cell envelope consisted of a peptidoglycan layer of approximately 10 nm thickness combined with an outer membrane. Cell division was intermediate between the constrictive and the septum type. The nucleoplasm, which contained several carboxysomes, was surrounded by 7-11 concentrically arranged thylakoids, which were predominantly stacked, with the exception of distinct areas where phycobiliproteins were located. The thylakoids were perforated by channel-like structures connecting the central and peripheral portions of the cytoplasm and not yet observed in other organisms. In freeze fractures, the protoplasmic fracture faces of thylakoid membranes were densely covered with particles of inhomogenous size. The particle size histogram peaked at 10-11, 13 and 18 nm. The 18-nm particles are assumed to represent photosystem I trimers. The particles on exoplasmic fracture faces, proposed to represent photosystem II complexes, were significantly larger than the corresponding particles of cyanobacteria and clustered to form large aggregates. This kind of arrangement is unique among photosynthetic organisms.

Direct refinement against proton-proton dipolar couplings in NMR structure determination of macromolecules

The computational tools necessary for making use of (1)H-(1)H dipolar couplings in macromolecular structure refinement are presented. Potentials are described for direct refinement against (1)H-(1)H dipolar couplings of known sign as well as of unknown sign. In addition, a multiple potential is developed for prochiral protons whose stereospecific assignments are unknown. The utility of direct (1)H-(1)H dipolar coupling refinement is illustrated using the small protein ubiquitin. It is shown that direct (1)H-(1)H dipolar coupling refinement leads to improvements in the precision, accuracy, and quality of the resulting structures.

Molecular structure, localization and function of biliproteins in the chlorophyll a/d containing oxygenic photosynthetic prokaryote Acaryochloris marina

We investigated the localization, structure and function of the biliproteins of the oxygenic photosynthetic prokaryote Acaryochloris marina, the sole organism known to date that contains chlorophyll d as the predominant photosynthetic pigment. The biliproteins were isolated by means of sucrose gradient centrifugation, ion exchange and gel filtration chromatography. Up to six biliprotein subunits in a molecular mass range of 15.5-18.4 kDa were found that cross-reacted with antibodies raised against phycocyanin or allophycocyanin from a red alga. N-Terminal sequences of the alpha- and beta-subunits of phycocyanin showed high homogeneity to those of cyanobacteria and red algae, but not to those of cryptomonads. As shown by electron microscopy, the native biliprotein aggregates are organized as rod-shaped structures and located on the cytoplasmic side of the thylakoid membranes predominantly in unstacked thylakoid regions. Biochemical and spectroscopic analysis revealed that they consist of four hexameric units, some of which are composed of phycocyanin alone, others of phycocyanin together with allophycocyanin. Spectroscopic analysis of isolated photosynthetic reaction center complexes demonstrated that the biliproteins are physically attached to the photosystem II complexes, transferring light energy to the photosystem II reaction center chlorophyll d with high efficiency.

Special education services provided to students with and without parental reports of traumatic brain injury

The purpose of this study was to determine the frequency and type of special education services provided to youths who had sustained one or more traumatic brain injuries (TBIs) according to parental report but who did not have verified TBIs according to school records. A parental questionnaire formulated for a related research project served as the basis for data collection. Results indicated the most common special education verification categories both for students with and without reported TBIs were speech-language impairment and specific learning disability. Approximately 29% of children with reported TBIs received special education services--a percentage not differing significantly from students without TBIs. However, students with TBIs whose parents reported long-term consequences were significantly more likely to receive special education services than students with TBIs whose parents did not report long-term consequence or students without TBIs. A chi-square analysis using the number of students whose reported TBIs occurred before versus after special education evaluations revealed no significant difference in the types of services received. However, those evaluated for special education services after sustaining TBIs were more than two times as likely to receive services for behavioural disorders than those evaluated prior to sustaining TBIs.

Isolation of genes involved in gravitropism

When upright growing wild type barley seedling are placed to a horizontal position they will respond to this gravistimulation by a curvature against the gravitational force. The mutant serpentina, however, shows gravitropic response only in an early stage of development. Older seedlings, gravistimulated 92 h after germination are agravitropic. They will grow horizontally. We try to identify genes involved in gravitropism by comparing gene expression of i) non-gravistimulated and gravistimulated wild type barley seedlings and of ii) gravistimulated wild type and serpentina.

Isolation and characterization of biliprotein aggregates from Acaryochloris marina, a Prochloron-like prokaryote containing mainly chlorophyll d

Phycobiliprotein aggregates were isolated from the prokaryote Acaryochloris marina, containing chlorophyll d as major pigment. In the electron microscope the biliprotein aggregates appear as rod-shaped structures of 26.0 x 11.3 nm, composed of four ring-shaped subunits 5.8 nm thick and 11.7 nm in diameter. Spectral data indicate that the aggregates contain two types of biliproteins: phycocyanin and an allophycocyanin-type pigment, with very efficient energy transfer from the phycocyanin- to allophycocyanin-type constituent. The chromophore-binding polypeptides of the pigments have apparent molecular masses of 16.2 and 17.4 kDa. They crossreact with antibodies against phycocyanin and allophycocyanin from a red alga.

Survey of free-ranging elk from Wyoming and Montana for selected pathogens

From December 1991 through January 1995, a disease survey was conducted on herds of free-ranging, hunter-killed elk (Cervus elaphus nelsoni) from three areas in proximity to Yellowstone National Park (YNP), Wyoming (USA), after tuberculosis caused by Mycobacterium bovis was discovered in a captive herd of elk in the area. Complete or partial sets of specimens from 289 elk collected between December 1991 and January 1993 were examined histologically; no mycobacterial lesions were observed. Lesions of tuberculosis were not detected in tonsils or lymph nodes of the head from an additional 99 hunter-killed, adult elk from one area (area 2) collected in January 1995. Neither M. bovis nor M. paratuberculosis were isolated from any of the specimens cultured. Antibodies to Brucella abortus were detected in serum samples from 0%, 1%, and 1% of elk from three areas sampled (areas 1, 2 and 3), respectively. Brucella abortus biovar 1 was isolated from multiple tissues from one seropositive animal from area 3. Larvae with morphology consistent with Dictyocaulus sp. were found in 12%, 14%, and 0% of fecal specimens tested from areas 1, 2, and 3, respectively. Pasteurella multocida and Actinomyces pyogenes were isolated from a lung with purulent bronchopneumonia and abscesses.

Biochemical and functional properties of photosystem II in agranal membranes from maize mesophyll and bundle sheath chloroplasts

We have studied the occurrence and organization of photosystem II (PSII) in bundle sheath thylakoids and stroma lamellae from maize. As shown by non-denaturing lauryl beta-D- iminopropionidate (Deriphat)/PAGE, PSII exists in a dimeric form in grana membranes. In bundle sheath and stroma lamellae, however, only a monomeric form was found. Based on immunotitration data, we estimated the stoichiometry of the individual components of the PSII core complex and antenna systems. In stroma lamellae, all PSII antenna complexes had a stoichiometry similar to that in grana membranes, with the exception of light-harvesting complex II (LHCII) that was somewhat over-represented, while the minor antenna complexes CP26 and CP29 were under-represented. In bundle sheath, the amount of LHCII was approximately eight times higher than expected with respect to D1. The 33-kDa protein of the oxygen-evolving enhancer polypeptides was not detectable nor was the ferredoxin-NADP+ reductase, thus strongly suggesting that no significant linear electron transport occurs in bundle sheath thylakoids. Fluorescence induction data suggest that most of the PSII reaction centers in bundle sheath and stroma lamellae sustain electron transport towards a secondary acceptor pool. Stromal PSII centers are only weakly inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), whereas, unexpectedly, dichlorobenzoquinone and methyl viologen had a pronounced inhibitory effect of the QA- reoxidation. An additional specificity of these centers is the slow rate (50-ms range) of the QA to QB electron transfer. The amplitude of variable fluorescence found in stroma lamellae can only account for a small fraction (1-2%) of the variable fluorescence of whole thylakoids. This suggests that stromal PSII cannot be solely responsible for the slow beta-phase of the induction kinetics.

Proteins induced by recombinant equine interferon-beta 1 within equine peripheral blood mononuclear cells and polymorphonuclear neutrophilic granulocytes

Peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophilic granulocytes (PMN) as well as embryonic equine dermal fibroblasts and the equine fibroblast line E. Derm which were used as controls, were treated with recombinant equine interferon-beta 1 (rEqIFN-beta 1) in vitro which induced the expression of different proteins in these cells. A 74 kDa protein was induced in PBMC and an 82 kDa protein was additionally found in the equine fibroblast E. Derm cell line following treatment with rEqFN-beta 1. Both proteins reacted with anti-mouse and anti-human Mx protein antisera in immunoblot tests. The 74 kDa and perhaps the 82 kDa components may thus represent equine 'Mxanalogous proteins'. The 74 kDa protein was only detected in PBMC of ten out of 20 horses examined. The induction of Mx protein in the horse by Type 1 interferon may therefore resemble that in the mouse, where Mx protein is involved in selective resistance to influenza virus. The influence of rEqIFN-beta 1 on protein expression in equine PBMC and PMN was monitored by metabolic labeling and 2-D gel electrophoresis. Proteins of 82, 74, 58 and 40 kDa were induced in PBMC following exposure to rEqIFN-beta 1. A constitutively expressed 35 kDa protein, however, was no longer demonstrable upon treatment with interferon. None of the proteins induced within PBMC was found in highly purified PMN treated with interferon. PMN exposed to rEqIFN-beta 1 synthesized four proteins in the range of 25 to 27 kDa. These proteins have not been described in interferon-treated PMN of any other species.

Solution structure of the DNA-binding domain of Drosophila heat shock transcription factor

The solution structure of the DNA-binding domain of the Drosophila heat shock transcription factor, as determined by multidimensional multinuclear NMR, resembles that of the helix-turn-helix class of DNA-binding proteins. The domain comprises a four-stranded antiparallel beta-sheet, packed against a three-helix bundle. The second helix is significantly distorted and is separated from the third helix by an extended turn which is subject to conformational averaging on an intermediate time scale. Helix 3 forms a classical amphipathic helix with polar and charged residues exposed to the solvent. Upon titration with DNA, resonance shifts in the backbone and Asn and Gln side-chain amides indicate that helix 3 acts as the recognition helix of the heat shock transcription factor.

Kinetics of inhibition of replication of vesicular stomatitis virus in blood mononuclear cells of horses after in vitro and in vivo treatment with recombinant equine interferon-beta 1

Recombinant equine interferon-beta 1 (reqIFN-beta 1) induces an antiviral state in blood mononuclear cells (BMC) of horses. Maximal protection against replication of vesicular stomatitis virus is achieved 6 hours after treatment with IFN in vitro and in vivo. Duration of the protective effect depends on the dose of IFN in vitro and in vivo. Availability of reqIFN-beta 1 in cultures of BMC for up to 48 hours does not prolong the antiviral state. The protective effect on BMC after treatment with IFN has similar duration in vivo and in vitro. Monitoring of the effect of IFN in vivo is, thus, simplified because the antiviral state may be recorded by testing cells twice (ie, before and 6 hours after application of interferon). All further tests may be performed in vitro. Multiple administration of reqIFN-beta 1 do not prolong duration of the protective phases after each administration. Duration of the antiviral state depends only on the dose of reqIFN-beta 1.

Carotenoid-binding proteins of photosystem II

The distribution of the photosynthetic pigments of the chlorophyll-binding proteins or photosystem-II membranes, isolated from dark-adapted maize leaves was determined. Most (80%) of a xanthophyll, violaxanthin, was found in the three minor chlorophyll-a/b proteins CP24, CP26 and CP29 whose function is unknown. Violaxanthin is the precursor of zeaxanthin, which is involved in dissipating excess excitation energy into heat [Demmig-Adams, B. (1991) Biochim. Biophys. Acta 1020, 1-24] under conditions of high transmembrane pH gradient [Gilmore, A. M. & Yamamoto, H. Y. (1992) Proc. Natl Acad. Sci. USA 89, 1899-1903]. We propose that a role for the minor photosystem-II chlorophyll-a/b proteins is the regulation of energy transfer to the reaction centre. It was also confirmed that the photosystem II reaction centre (D1-D2-cytochrome b559) contains beta-carotene as the only carotenoid. However, the two other chlorophyll-a-binding proteins of photosystem II, CP47 and CP43, bind not only beta-carotene, but also the xanthophyll lutein, previously thought to be restricted to chlorophyll-a/b proteins.

"Discordant" influence of equine recombinant interferon-beta 1 on the cytotoxic capacity of equine polymorphonuclear neutrophils and peripheral blood mononuclear cells in vitro and in vivo

The influence of recombinant equine interferon-beta 1 (rEqIFN-beta 1) on mononuclear cells of peripheral blood (PBMC) and polymorphonuclear neutrophilic granulocytes (PMN) was tested under in vitro and ex vivo conditions. Treatment of equine PBMC with IFN in vitro enhanced the antibody-independent cytotoxicity (AICC) and antibody-dependent cytotoxicity (ADCC) while there was no significant effect on the cytotoxic capacity of PMN treated with rEqIFN-beta 1 in vitro. Ex vivo there was an increased capacity of AICC and ADCC upon single or multiple application of rEqIFN-beta 1 in PMN, only. Treatment with rEqIFN-beta 1 thus induced an increased cellular cytotoxicity in vitro and in vivo but in different populations of peripheral blood cells. In vivo rEqIFN-beta 1 causes a pronounced activation of PMN but not of PBMC as cytotoxic effector cells. This might be achieved indirectly, e.g., by cytokines produced by IFN-sensitive cells.

Monitoring of effects induced by recombinant equine interferon-beta 1 in whole blood and separated fractions of peripheral blood of horses

Interferon is known to induce antiviral mechanisms and to exert immunoregulatory capacities on various cell types. The antiviral capacity of recombinant equine interferon-beta 1 (rEqIFN-beta 1) is most sensitively monitored by indirect quantitation of multiplication of vesicular stomatitis virus (VSV) in blood cells of horses. As few as 0.5 pg rEqIFN-beta 1/ml can be assessed by means of 90% reduction of VSV-replication in whole blood (w.b.) as well as in isolated mononuclear blood cells (MNC) in spite of individual variations. The immunoregulatory influence of 20-50 pg rEqIFN-beta 1/ml is sufficient to cause at least a 50% reduction of mitogen-induced lymphocyte proliferation in MNC, while higher concentrations are needed in w.b. Of the mitogens tested the best stimulation of proliferation on the equine lymphoid cells was obtained with staphylococcal enterotoxin B (SEB). Release of reactive oxygen species (ROS) from phagocytic cells in w.b. or from isolated polymorphonuclear cells (PMN) as monitored by chemiluminescence (CL) does not seem suitable for evaluation of rEqIFN-beta 1-induced immunoregulation as only very high rEqIFN-beta 1-concentrations (10(3)-10(4) pg/ml) result in a minute increase (up to 20%) of CL. Comparative studies on w.b. and isolated leukocyte fractions from identical specimens of individual horses suggest that monitoring of antiviral and distinct immunoregulatory capacities of rEqIFN-beta 1 can be performed on w.b. without loss of information and sensitivity as compared to isolated MNC.

Fractionation of thylakoid membranes from Porphyridium purpureum using the detergent N-lauryl-β-iminodipropionate : A study on the chlorophyll-protein and pigment composition of the membrane-intrinsic antenna complexes of a red alga

Two green fractions, thought to represent the chlorophyll-antennae of photosystems I (PSI) and II (PSII), were isolated from the red alga Porphyridium purpureum by solubilisation of the thylakoid membranes using the detergent N-lauryl-ß-iminodipropionate and subsequent sucrose-density-gradient centrifugation. No release of pigments from the pigment-protein complexes was detected during isolation. The fractions were analyzed with respect to their chlorophyll-protein pattern, spectral properties and pigment composition. The supposed PSII antenna fraction contained both the major carotenoids of P. purpureum, β-carotene and zeaxanthin, and showed a long-wavelength absorption maximum at 672 nm and a low-temperature fluorescence maximum at 692-694 nm. Polypeptides of this fraction cross-reacted with antibodies raised against the PSII polypeptides D1, CP43 and CP47 from higher plants. The PSI fraction could perform P-700 photooxidation and showed a long-wavelength absorbance maximum at 679 nm and a low-temperature fluorescence maximum at 718 nm. It contained β-carotene as the only carotenoid. The fluorescence excitation spectrum of the fraction and measurements of the photochemical activity of a thylakoid preparation excited with light that is preferentially absorbed either by chlorophyll (433 nm) or by carotenoids (495 nm) indicate that β-carotene serves as a very efficient antenna-pigment in PSI. In contrast, only a small amount of energy transfer from the carotenoids to chlorophyll could be observed with the supposed PSII fraction.

A method for the assay of "difficult" interferons exemplified with recombinant equine interferon-beta 1

We wished to assay recombinant equine interferon-beta 1 (rEqIFN-beta 1) but could not obtain satisfactory results with previously described methods. Therefore, we developed a yield-reduction assay, using primary horse peripheral blood mononuclear cells (PBMC) with vesicular stomatitis virus (VSV) for challenge, which proved consistently satisfactory and highly sensitive. It is suggested that this method of assay may be useful for IFNs from other animals where problems are encountered.

The influence of colostral leukocytes on the immune system of the neonatal calf. IV. Effects on bactericidity, complement and interferon; synopsis

The influence of colostral leukocytes on the bactericidity of whole blood of calves against a strain of E. coli and on the activities of haemolytic complement and interferon-alpha (the antiviral activity of sera resisting an acidic treatment at pH 2 for 6 h) in the serum was investigated during a period of 4 weeks using 4 experimental groups. The calves received either complete colostrum (COL+, n = 16), cell-depleted colostrum (COL-, n = 16), cell-supplemented milk substitute (MS+, n = 7) or pure milk substitute (MS-, n = 6) during their first three days of life. The bactericidity of whole blood of the COL+ group was significantly higher on the second and third days of life while the activity of haemolytic complement was lower after the first week as compared to the COL- group. No interferon-alpha was detectable in the sera of both COL groups. The bactericidity of the MS groups was significantly lower than that of the COL groups after the first day of life. It was significantly lower in the MS+ group after one week of life while the activity of haemolytic complement was higher than that of the MS- group. Three out of 5 MS- and only one out of 7 MS+ calves had low titres of interferon-alpha in their sera on the third day. Three out of 6 MS- calves died and 5 out of 7 MS+ animals. The mean day of death was 4.0 in the MS- and 8.4 in the MS+ group. Based on the in vitro results of this and the previous three communications it can be concluded that leukocytes which are an integral part of normal bovine colostrum, influence immunological reactions of the calf and that they may enhance its defence against infection. Colostral leukocytes in the absence of humoral components of the colostrum are not able to prevent fatal losses in the calves due to natural infection, although their influence on immune responses of the calves was detectable in vitro.