An integrated chemical and micromorphological investigation of humic substances in three podzolized soils of the Netherlands.

The humic substances in a 'Holt' leptic podzol, a 'Haar' humic podzol and a 'Veld' gleyic podzol from the Netherlands were analysed chemically and micromorphologically. The absorption spectra of Na-humates in visible light and infrared spectra were determined for the humic acids. The translocation and distribution of the principal humus compounds occurred by mechanical illuviation in the 'Holt' podzol, and by translocation in solution in the 'Haar' podzol and the 'Veld' podzol. The micromorphological images were closely correlated with the chemical composition of the humic substances. Illuviation cutans occurring in the B horizons of the 'Haar' podzol and the 'Veld' podzol appeared to consist mainly of fulvic acids. The dark humus micro-aggregates characteristic of the 'Haar' podzol and the Ap horizon of the 'Veld' podzol were composed mainly of bitumens, humins and humic acids of high molecular weight, while the brown micro-aggregates of the 'Holt' podzol and the lower horizons of the 'Veld' podzol consisted mainly of fulvic acids and humic acids of low molecular weight. The stability of micro-aggregates was correlated with their composition. (Abstract retrieved from CAB Abstracts by CABI’s permission

Saccharomyces cerevisiae Ski7 Is a GTP-Binding Protein Adopting the Characteristic Conformation of Active Translational GTPases

Ski7 is a cofactor of the cytoplasmic exosome in budding yeast, functioning in both mRNA turnover and non-stop decay (NSD), a surveillance pathway that degrades faulty mRNAs lacking a stop codon. The C-terminal region of Ski7 (Ski7(C)) shares overall sequence similarity with the translational GTPase (trGTPase) Hbs1, but whether Ski7 has retained the properties of a trGTPase is unclear. Here, we report the high-resolution structures of Ski7(C) bound to either intact guanosine triphosphate (GTP) or guanosine diphosphate-Pi. The individual domains of Ski7(C) adopt the conformation characteristic of active trGTPases. Furthermore, the nucleotide-binding site of Ski7(C) shares similar features compared with active trGTPases, notably the presence of a characteristic monovalent cation. However, a suboptimal polar residue at the putative catalytic site and an unusual polar residue that interacts with the g-phosphate of GTP distinguish Ski7 from other trGTPases, suggesting it might function rather as a GTP-binding protein than as a GTP-hydrolyzing enzyme

Final del juego

El tema de este trabajo es la construcción de la temporalidad en la imagen. Realizamos un video que alude a dos juegos de figuras estáticas y encuadres móviles que se repiten. En un juego de efectos ópticos, el zootropo, las figuras estáticas se observan a través de las ranuras de un cilindro que gira; en un cuento de Cortázar, "Final del juego", las hermanas que juegan a ser estatuas, son observadas desde la ventanilla de un tren en movimiento. La repetición de los juegos se da porque el dispositivo es circular o porque constituye una rutina. El movimiento, el estatismo y la repetición de las figuras son los ejes de la propuesta. A partir de ellos intentamos construir la temporalidad en la imagen.El video que acompaña a esta tesis de grado puede verse en este enlace.Facultad de Bellas Arte

Ultrasound imaging for measuring the material and mechanical properties of the Achilles tendon: inter-day reliability and correlation with a functional calf length test

poster abstractPurpose/Hypothesis: The ability to objectively assess Achilles tendon length and mechanical properties can be challenging because other factors such as muscle and joint mechanics can complicate standard clinical tests. Ultrasound imaging has the ability to provide isolated objective measures of the material and mechanical properties of the Achilles tendon. The primary aim of this study was to assess the inter-day reliability of the material and mechanical properties of the Achilles tendon in a single rater. A secondary aim was to investigate whether there was any relationship between measured tendon properties and calf muscle length measured with a lunge test. Number of subjects: Ten Achilles tendons in 5 subjects (all subjects were 24 years old; 80% female). Material/Methods: Healthy subjects attended 2 identical measurement sessions, 2 days apart. Subjects were measured at the same time of day and were encouraged to perform the same pre-test activities. Immediately prior to the ultrasound imaging, functional calf length was measured in standing with a lunge test. Subjects were then positioned prone with the knee extended and ankle held at 0 degrees of dorsiflexion, and measurements of the resting tendon length and tendon cross-sectional area were obtained from static ultrasound images. Tendon elongation was measured during isometric dynamometry through imaging the proximal movement of the musculotendinous junction of the medial gastrocnemius. Tendon strain was measured at maximum isometric torque. Intra-class correlation coefficients (ICCs) were calculated to determine the reliability of the ultrasound measures. The correlation between tendon properties and the lunge test were examined using a Pearson correlation coefficient, with the level of significance set at 0.05. Results: Reliability analysis demonstrated high inter-day test-retest reliability for resting Achilles tendon length (ICC = 0.95), cross-sectional area (ICC = 0.96) and strain (ICC = 0.95). Tendon elongation measured with ultrasound imaging during peak isometric force had good reliability (ICC = 0.81). A moderate correlation was found between resting tendon length and the lunge test on each day of testing; Day 1 (r=0.67, r2=0.45, p=0.034) and Day 2 (r=0.66, r2=0.44, p=0.038). Conclusion: Ultrasound imaging measurements of the material and mechanical properties of the Achilles tendon has good-to-high inter-day reliability in a single rater. It was also determined that Achilles tendon resting length accounted for ~45% of the variance in the lunge test, indicating other factors contribute to lunge test performance. The later may include talocrural and subtalar joint motion, and length of the gastrocnemius and soleus muscles. Clinical relevance: Ultrasound imaging can be used as a reliable, safe and cost-effective tool to measure isolated Achilles tendon properties. This may allow future studies to explore intervention effects on the material and mechanical characteristics of the tendon

Final del juego

El tema de este trabajo es la construcción de la temporalidad en la imagen. Realizamos un video que alude a dos juegos de figuras estáticas y encuadres móviles que se repiten. En un juego de efectos ópticos, el zootropo, las figuras estáticas se observan a través de las ranuras de un cilindro que gira; en un cuento de Cortázar, "Final del juego", las hermanas que juegan a ser estatuas, son observadas desde la ventanilla de un tren en movimiento. La repetición de los juegos se da porque el dispositivo es circular o porque constituye una rutina. El movimiento, el estatismo y la repetición de las figuras son los ejes de la propuesta. A partir de ellos intentamos construir la temporalidad en la imagen.El video que acompaña a esta tesis de grado puede verse en este enlace.Facultad de Bellas Arte

Полеміка навколо наукової спадщини Володимира Антоновича в українській історіографії радянської доби

(uk) Проаналізовано стан дослідження наукової спадщини класика української історіографії В.Б. Антоновича в працях істориків різних ідеологічних спрямувань. Указано на відмінності теоретичних узагальнень щодо творчості вченого в національно-державницькій та марксистській науці радянської доби.(ru) Проанализировано состояние исследования научного наследия классика украинской историографии В. Б. Антоновича в работах историков различных идеологических направлений. Подчеркнуты различия теоретических обобщений относительно творчества в национально-государственной и марксистской науке советского периода.(en) The state of investigation of V.B. Antonovich\s scientific activity in the researches of historians of different ideological direction was analyzed. It is pointed out the differences of theoretical generalization about activity of scientist in national state and marxist historical science of Soviet epoch

Molecular mechanism of influenza A NS1-mediated TRIM25 recognition and inhibition

RIG-I is a viral RNA sensor that induces the production of type I interferon (IFN) in response to infection with a variety of viruses. Modification of RIG-I with K63-linked poly-ubiquitin chains, synthesised by TRIM25, is crucial for activation of the RIG-I/MAVS signalling pathway. TRIM25 activity is targeted by influenza A virus non-structural protein 1 (NS1) to suppress IFN production and prevent an efficient host immune response. Here we present structures of the human TRIM25 coiled-coil-PRYSPRY module and of complexes between the TRIM25 coiled-coil domain and NS1. These structures show that binding of NS1 interferes with the correct positioning of the PRYSPRY domain of TRIM25 required for substrate ubiquitination and provide a mechanistic explanation for how NS1 suppresses RIG-I ubiquitination and hence downstream signalling. In contrast, the formation of unanchored K63-linked poly-ubiquitin chains is unchanged by NS1 binding, indicating that RING dimerisation of TRIM25 is not affected by NS1

Structure of a Cytoplasmic 11-Subunit RNA Exosome Complex

The RNA exosome complex associates with nuclear and cytoplasmic cofactors to mediate the decay, surveillance, or processing of a wide variety of transcripts. In the cytoplasm, the conserved core of the exosome (Exo10) functions together with the conserved Ski complex. The interaction of S. cerevisiae Exo10 and Ski is not direct but requires a bridging cofactor, Ski7. Here, we report the 2.65 angstrom resolution structure of S. cerevisiae Exo10 bound to the interacting domain of Ski7. Extensive hydrophobic interactions rationalize the high affinity and stability of this complex, pointing to Ski7 as a constitutive component of the cytosolic exosome. Despite the absence of sequence homology, cytoplasmic Ski7 and nuclear Rrp6 bind Exo(10) using similar surfaces and recognition motifs. Knowledge of the interacting residues in the yeast complexes allowed us to identify a splice variant of human HBS1-Like as a Ski7-like exosome-binding protein, revealing the evolutionary conservation of this cytoplasmic cofactor

Sphinx measurements of the 2009 solar minimum x-ray emission

The SphinX X-ray spectrophotometer on the CORONAS-PHOTON spacecraft measured soft X-ray emission in the 1-15 keV energy range during the deep solar minimum of 2009 with a sensitivity much greater than GOES. Several intervals are identified when the X-ray flux was exceptionally low, and the flux and solar X-ray luminosity are estimated. Spectral fits to the emission at these times give temperatures of 1.7-1.9 MK and emission measures between 4 x 10^47 cm^-3 and 1.1 x 10^48 cm^-3. Comparing SphinX emission with that from the Hinode X-ray Telescope, we deduce that most of the emission is from general coronal structures rather than confined features like bright points. For one of 27 intervals of exceptionally low activity identified in the SphinX data, the Sun's X-ray luminosity in an energy range roughly extrapolated to that of ROSAT (0.1-2.4 keV) was less than most nearby K and M dwarfs.Comment: Astrophysical Journal, in press. 14 pp, 3 figure