Correlation of vibrational excitations and electronic structure with submolecular resolution

The detection of vibrational excitations of individual molecules on surfaces by scanning tunneling spectroscopy does not obey strict selection rules but rather propensity rules. The experimental verification of these excitations is challenging because it requires the independent variation of specific parameters, such as the electronic structure, while keeping the vibrational modes the same. Here, we make use of the versatile self-assembled structures of Fe-tetra-pyridyl-porphyrin molecules on a Au(111) surface. These molecules exhibit different energy-level alignments of the frontier molecular orbitals, thus allowing the correlation of the electronic structure and detection of vibrations. We identify up to seven vibrational modes in the tunneling spectra of the molecules in some of the arrangements, whereas we observe none in other structures. We find that the presence of vibrational excitations and their distribution along the molecule correlate with the observation of energetically low-lying molecular states. This correlation allows the explanation of the different numbers of vibrational signatures for molecules embedded within different structures as well as the bias asymmetry of the vibrational intensities within an individual molecule. Our observations are in agreement with the resonant enhancement of vibrations by the virtual excitation of electronic states

PCNA acts as a stationary loading platform for transiently interacting Okazaki fragment maturation proteins

In DNA replication, the leading strand is synthesized continuously, but lagging strand synthesis requires the complex, discontinuous synthesis of Okazaki fragments, and their subsequent joining. We have used a combination of in situ extraction and dual color photobleaching to compare the dynamic properties of three proteins essential for lagging strand synthesis: the polymerase clamp proliferating cell nuclear antigen (PCNA) and two proteins that bind to it, DNA Ligase I and Fen1. All three proteins are localized at replication foci (RF), but in contrast to PCNA, Ligase and Fen1 were readily extracted. Dual photobleaching combined with time overlays revealed a rapid exchange of Ligase and Fen1 at RF, which is consistent with de novo loading at every Okazaki fragment, while the slow recovery of PCNA mostly occurred at adjacent, newly assembled RF. These data indicate that PCNA works as a stationary loading platform that is reused for multiple Okazaki fragments, while PCNA binding proteins only transiently associate and are not stable components of the replication machinery

ESTIMATING LUMBAR SPINE LOADING DURING VOLLEYBALL SPECIFIC MOVEMENTS USING 3D MODELING

Volleyball has a high prevalence of back pain resulting from degenerated intervertebral discs in the lumbar spine. Therefore knowledge about volleyball specific spine loading and its direction is very important. In this study a method is introduced to calculate spine forces in volleyball specific situations also accounting for muscle forces. Two players performed volleyball specific movements in a laboratory environment. Kinematic data were captured by an infrared camera system. An inverse dynamic model was used to calculate spine forces in all three movement planes. Results indicate that the spike has the highest loading. However, peak loading was recognized in phases of takeoff and landing. The presented method was found to be adequate and might be used for further research to get a more comprehensive insight into the topic

A Machine Learning-Based Raman Spectroscopic Assay for the Identification of Burkholderia mallei and Related Species

Burkholderia (B.) mallei, the causative agent of glanders, and B. pseudomallei, the causative agent of melioidosis in humans and animals, are genetically closely related. The high infectious potential of both organisms, their serological cross-reactivity, and similar clinical symptoms in human and animals make the differentiation from each other and other Burkholderia species challenging. The increased resistance against many antibiotics implies the need for fast and robust identification methods. The use of Raman microspectroscopy in microbial diagnostic has the potential for rapid and reliable identification. Single bacterial cells are directly probed and a broad range of phenotypic information is recorded, which is subsequently analyzed by machine learning methods. Burkholderia were handled under biosafety level 1 (BSL 1) conditions after heat inactivation. The clusters of the spectral phenotypes and the diagnostic relevance of the Burkholderia spp. were considered for an advanced hierarchical machine learning approach. The strain panel for training involved 12 B. mallei, 13 B. pseudomallei and 11 other Burkholderia spp. type strains. The combination of top- and sub-level classifier identified the mallei-complex with high sensitivities (>95%). The reliable identification of unknown B. mallei and B. pseudomallei strains highlighted the robustness of the machine learning-based Raman spectroscopic assay

Mechanism of angiotensin converting enzyme inhibitor-related anemia in renal transplant recipients

Mechanism of angiotensin converting enzyme inhibitor-related anemia in renal transplant recipients. To delineate the pathogenesis of the reduction in hemoglobin occurring in renal transplant patients treated with angiotensin converting enzyme inhibitors (ACEI) and azathioprine (AZA) a controlled, prospective trial of ACEI withdrawal was conducted. The ACEI was replaced by nifedipine or clonidine in 15 kidney transplant patients immunosuppressed with AZA and prednisone (enalapril in 14 and captopril in 1). Before and during 10 to 12 weeks after withdrawal of the ACEI, AZA metabolites, renal function parameters and hematological parameters including erythropoietin and reticulocytes were evaluated. Enalaprilat levels were measured and compared with 15 similar patients matched for transplant function and enalapril dosage immunosuppressed with cyclosporine and prednisone. AZA metabolites did not differ significantly in the presence or absence of the ACEI. Enalaprilat levels also showed no significant difference between the two patient groups treated with AZA or cyclosporine. Hematocrit and hemoglobin increased significantly from 37.5 ± 6.4 to 39.7 ± 3.6% (mean ± SD, P = 0.02) and 12.8 ± 2.2 to 13.5 ± 1.2 g/dl, P = 0.04, respectively, 10 to 12 weeks after ACEI treatment had been discontinued. Simultaneously numbers of reticulocytes and erythropoietin concentrations rose significantly after 2, 4 and 10 weeks, with a peak at two weeks (from 14.1 ± 3.8 to 20.6 ± 8.0%, P < 0.05 and from 14.3 ± 12.4 to 29.3 ± 54.5 mU/ml, P < 0.05, respectively). In conclusion, ACEI-related anemia in renal transplant recipients seems to be due to the erythropoietin-lowering effect of this group of drugs. A pharmacokinetic interaction between AZA and enalapril is not likely since plasma enalaprilat levels were independent of the immunosuppressive regimen and AZA metabolite levels were unchanged in the presence and absence of the ACEI. Several mechanisms by which angiotensin converting enzyme blockade may cause a decrease in circulating erythropoietin are discussed

"urbs libzi"-Geoarchäologische Untersuchungen an der Hainspitze in Leipzigs Innenstadt

Die Verfüllung von archäologischen Befunden ist bedeutend für Informationen zur Nutzungs- und Auflassungsgeschichte. In interdisziplinärer Zusammenarbeit wurde versucht, die Geschichte zweier anthropogener Strukturen zu untersuchen und anhand der Ergebnisse eine verbesserte Einschätzung der frühen Stadtgeschichte Leipzigs zu erhalten. Die geoarchäologischen Untersuchungen erfolgten im Bereich einer vermutlich hochmittelalterlichen Materialentnahmegrube sowie des ehemaligen Außengrabens der „urbs libzi“, der das Vorburggelände nach Osten hin abschloss. In die Arbeiten wurde auch ein weitgehend ungestörter Bereich einbezogen. Die freigelegten Profile wurden 2012 im Gelände dokumentiert und beprobt. Das entnommene Material wurde geochemisch untersucht. An Proben besonders exponierter Standorten wurden außerdem Dünnschliffe erstellt, die unter dem Polarisationsmikroskop interpretiert wurden. In dauerhaft feuchten Sedimenten sind meist Pollenkörner zu finden, welche die bei der Entstehung der Verfüllung vorhandene Vegetation widerspiegeln. Die beiden unterschiedlichen Verfüllungen werden durch die Korngrößenverteilung und die Kohlenstoffgehalte deutlich. Stellenweise deuten hohe Phosphor- und Stickstoffwerte in der oberen Verfüllung auf eine starke Kontamination mit organischem Abfall hin. Die geoarchäologischen Untersuchungen haben wichtige neue Erkenntnisse zur Zeit der Stadtwerdung erbracht. Der hochmittelalterliche Graben war kein Wassergraben, ist zu großen Teilen intentionell verfüllt worden und blieb danach mehrere Jahrzehnte unbebaut. Die mittelalterliche Materialentnahmegrube belegt den Bedarf an sandig-kiesigem Baumaterial in der frühen Phase der Stadtwerdung. Pseudogleye an der urbs libzi zeigen, dass die geomorphologische und verkehrgeographische Lage für die Burganlage wichtiger war als die Bodenqualität

Monitoring der Nährstoffein- und -austräge aus Reitplätzen

Untersucht werden v. a. zwei Reitplätze auf ihr Stickstoffemissionspotential. Hierzu werden Nitrat-, Ammonium- und Lachgasemissionen untersucht. Im Ergebnis zeigen die gebildeten Mittelwerte bisher keine Überschreitung bekannter Grenzwerte. Zur Einschätzung der erfassten Werte steht noch die Diskussion mit dem Projektbeirat aus

BAW-Brief Nr. 2 - Juli 2003

574-L, Wechsel der Leitung der Dienststelle Hamburg573-B, Bautechnik, Schweißen an Altstählen572-B, Bautechnik, Materialprüfzeugnisse für Ausrüstungsteile und Schweißzusatzwerkstoffe571-B, Bautechnik, Bericht einer ad-hoc-Arbeitsgruppe "Behindertengerechte Gestaltung von Schleusensteuerständen"570-G, Geotechnik, Neue Oberflächendichtungen für Wasserstraße