Sonographic cervical volumetry in higher order multiple gestation

Objective:The aim of this study of multifetal pregnancies was the comparison of three-dimensional (3D) volumetry of the cervix, conventional sonographic cervical length measurement and clinical assessment. Methods 10 mothers were investigated in an observational study between 5/1999 and 9/2000. A total of 34 consecutive 2D-and 3D-transabdominal ultrasound measurements were performed. Results: Volumetry of the cervix was possible in all 34 exams. 2D-cervical length assessment could not be obtained in 6% because the presenting fetal part obstructed the sonographic plane. Both methods allowed equal judgement of the configuration of the cervix. A significant correlation was found between mean 2D-cervical length (28.7 mm, 7.7 SD) and mean cervical volume (30.0 cm(3), 16.0 SD). Parity, subjective preterm labor or need of tocolytics showed no correlation with any biometrical parameter studied. Conclusion: Volumetry was superior for the assessment of cervical biometry and conformation in women when the transabdominal 2D-plane was obstructed. When cervical length was obtainable by a conventional scan, the technically more complex 3D-imaging did not provide further information. Copyright (C) 2001 S. Karger AG, Basel

Evaluation of producer cell lines for yellow fever virus production in up to 1 L bioreactor scale

Yellow fever virus (YFV) vaccine is currently produced in embryonated chicken eggs. Following recent outbreaks of flavivirus-related diseases, such as Zika fever, significant efforts are needed towards fast establishment of cell culture-based production processes for attenuated or inactivated virus vaccines. To support the development of such processes, we have screened various cell lines, including adherent and suspension cells, for permissiveness and productivity of YFV. In particular, the parental adherent Vero cell line possesses a reasonable cell-specific productivity of about 13 PFU/cell. However, surface-depended scale-up restricts production processes to roller bottles, microcarrier-based or fixed-bed bioreactors with limited monitoring and excessive efforts for large-scale production. A preferential alternative is the cultivation of single-cells in stirred-tank bioreactors, which can be operated in perfusion mode to achieve higher cell-densities. Towards this process intensification, we have adapted the parental WHO Vero cell line to grow in suspension. However, infection studies of Vero suspension cells with YFV in spinner flasks using chemically defined medium showed a reduced cell-specific titer (2 PFU/cell). Another option might be the use of BHK-21 cells reaching cell-densities above 5 × 106 cells/mL in shake flasks. Infection studies with YFV in small-scale have resulted in a cell-specific productivity of 10 PFU/cell. Thus, infection parameters (time of infection, MOI = ratio of virus to cell) were optimized and subsequently transferred into 1 L bioreactors. Final titer of 5 × 107 PFU/mL could be reached. As a reference, adherent Vero cells were cultivated on Cytodex-1 microcarriers in 1 L scale resulting in a final titer of 2 × 107 PFU/mL. In both cultivations, cell-specific yields were comparable but due to the adjusted MOI of 10-4 in the BHK-21 cultivation, the overall virus production was 50 × higher than for the Vero cultivation on microcarriers. Although BHK-21 cells and their application for human vaccines are controversial with respect to tumorigenicity and oncogenicity, our results show that it may be worth to reconsider this cell line for future production processes

Macroscopic Safety Requirements for Highly Automated Driving

The common expectation for highly automated vehicles (HAVs) is that an introduction will lead to increased road safety and a reduction in traffic fatalities—at least in relation to the mileage. However, quantizing the safety requirements is still in discussion. This paper analyzes the risk acceptance in other fields and applies the safety level on today’s traffic to derive references for acceptable risks. The focus is on macroscopic safety requirements, meaning accident rates per mileage, and not the behavior in individual driving situations. It was concluded that the acceptable risk varies according to the group involved and with the field share of automated vehicles. Increased safety of conventional driving in the future could lead to higher requirements as well. We also point out that it is not guaranteed that the given acceptable risk levels will also accepted by the user, because factors other than the accident statistics are relevant. However, as none of these risk levels can be proven before introduction, the monitoring of vehicles in the field is suggested. Despite increased research efforts in safety validation, uncertainty surrounding the safety of HAVs will remain at the time of introduction. Different introduction and risk management strategies are briefly introduced

Analysis of the acoustlc transients in the pulse response of the linear electro-optic effect

The pulse response of the linear electro-optic effect is investigated with high temporal and spatial resolution in KDP, KD*P, and biaxial LiCOOH · H2O. Experimental results, which are explained theoretically, show that the piezo-optic transients induced by the piezoelectric effect, are generated by stress release waves. Starting from the surfaces, these excite by reflection, diffraction, and superposition, due to the finite crystal dimensions, normal vibration modes too. It is shown that the direct electro-optic effect can be measured for all crystal classes at the beginning of the pulse response. The pulse method also yields static electro-optic, piezo-optic, and elastic constants. The values of r63, r63, p66 and c66 measured in KDP, agree well with those of other authors. Measurement of the direct electro-optic effect of LiCOOH · H2O in some directions yields values within 1 to 4 × 10-12 m/V

Ultracold chemical reactions of a single Rydberg atom in a dense gas

Within a dense environment ($\rho \approx 10^{14}\,$atoms/cm$^3$) at ultracold temperatures ($T < 1\,\mu{}\text{K}$), a single atom excited to a Rydberg state acts as a reaction center for surrounding neutral atoms. At these temperatures almost all neutral atoms within the Rydberg orbit are bound to the Rydberg core and interact with the Rydberg atom. We have studied the reaction rate and products for $nS$ $^{87}$Rb Rydberg states and we mainly observe a state change of the Rydberg electron to a high orbital angular momentum $l$, with the released energy being converted into kinetic energy of the Rydberg atom. Unexpectedly, the measurements show a threshold behavior at $n\approx 100$ for the inelastic collision time leading to increased lifetimes of the Rydberg state independent of the densities investigated. Even at very high densities ($\rho\approx4.8\times 10^{14}\,\text{cm}^{-3}$), the lifetime of a Rydberg atom exceeds $10\,\mu\text{s}$ at $n > 140$ compared to $1\,\mu\text{s}$ at $n=90$. In addition, a second observed reaction mechanism, namely Rb$_2^+$ molecule formation, was studied. Both reaction products are equally probable for $n=40$ but the fraction of Rb$_2^+$ created drops to below 10$\,$% for $n\ge90$.Comment: 13 pages, 13 figure

Zur Debatte: Deutsch als Wissenschaftssprache

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Breaking the Waves: Modelling the Potential Impact of Public Health Measures to Defer the Epidemic Peak of Novel Influenza A/H1N1

BACKGROUND: On June 11, 2009, the World Health Organization declared phase 6 of the novel influenza A/H1N1 pandemic. Although by the end of September 2009, the novel virus had been reported from all continents, the impact in most countries of the northern hemisphere has been limited. The return of the virus in a second wave would encounter populations that are still nonimmune and not vaccinated yet. We modelled the effect of control strategies to reduce the spread with the goal to defer the epidemic wave in a country where it is detected in a very early stage. METHODOLOGY/PRINCIPAL FINDINGS: We constructed a deterministic SEIR model using the age distribution and size of the population of Germany based on the observed number of imported cases and the early findings for the epidemiologic characteristics described by Fraser (Science, 2009). We propose a two-step control strategy with an initial effort to trace, quarantine, and selectively give prophylactic treatment to contacts of the first 100 to 500 cases. In the second step, the same measures are focused on the households of the next 5,000 to 10,000 cases. As a result, the peak of the epidemic could be delayed up to 7.6 weeks if up to 30% of cases are detected. However, the cumulative attack rates would not change. Necessary doses of antivirals would be less than the number of treatment courses for 0.1% of the population. In a sensitivity analysis, both case detection rate and the variation of R0 have major effects on the resulting delay. CONCLUSIONS/SIGNIFICANCE: Control strategies that reduce the spread of the disease during the early phase of a pandemic wave may lead to a substantial delay of the epidemic. Since prophylactic treatment is only offered to the contacts of the first 10,000 cases, the amount of antivirals needed is still very limited

Synthesis of Pure and Fe-Doped TiO2_2 Nanoparticles via Electrospray-Assisted Flame Spray Pyrolysis for Antimicrobial Applications

We report a straightforward aerosol-based approach to synthesizing pure and Fe-doped TiO$_2$ nanoparticles by continuous electrospray-assisted flame spray pyrolysis (EAFSP). Initially, pure TiO$_2$ nanoparticles were prepared by electrospraying titanium diisopropoxide bis(acetylacetonate) (TDIP) at varying concentrations onto a grounded flame. In this regard, various in situ (phase Doppler anemometry, high-speed camera, and scanning mobility particle sizer) and ex situ (small-angle X-ray scattering, transmission electron microscopy, and BET adsorption isotherms) diagnostics were applied for the analysis of the in-flight droplet characteristics in the spray, such as droplet μ-explosions, as well as primary and agglomerate nanoparticle evolution within the process and the particulate product. Moreover, single-particle ICP-MS (inductively coupled plasma–mass spectrometry) in situ measurements have been conducted to get insight into the process that causes various particle morphologies and to open up the option of an in situ determination of the particle formation route. Subsequently, the EAFSP method was utilized to produce Fe-doped TiO$_2$ nanoparticles. The influences of the Fe$^{3+}$ dopant concentration on the particle size, crystal structure, crystallite sizes, phase formation, oxygen vacancy defects, and optical gaps were systematically investigated. The presented EAFSP synthesis, in contrast to conventional flame spray pyrolysis (FSP) with gas atomization of the solvent/precursor, eliminates the need for dispersion gas and complex solvents, making it a more efficient and environmentally friendly method for nanoparticle synthesis. Finally, we studied the application potential of EAFSP-synthesized pure and Fe-doped TiO$_2$ nanoparticles for fighting bacteria resistant to an antibiotic, here spectinomycin-resistant Escherichia coli. A clear inhibitory effect of the Fe-doped TiO$_2$ nanoparticles could be observed during the growth of bacteria in the liquid medium, up to 99.4%. These results point out the high potential of the designed Fe-doped TiO$_2$ nanoparticles to act as antimicrobial agents and treatments against infections

Lack of a-disintegrin-and-metalloproteinase ADAM10 leads to intracellular accumulation and loss of shedding of the cellular prion protein in vivo

<p>Abstract</p> <p>Background</p> <p>The cellular prion protein (PrP^C) fulfils several yet not completely understood physiological functions. Apart from these functions, it has the ability to misfold into a pathogenic scrapie form (PrP^Sc) leading to fatal transmissible spongiform encephalopathies. Proteolytic processing of PrP^Cgenerates N- and C-terminal fragments which play crucial roles both in the pathophysiology of prion diseases and in transducing physiological functions of PrP^C. A-disintegrin-and-metalloproteinase 10 (ADAM10) has been proposed by cell culture experiments to be responsible for both shedding of PrP^Cand its α-cleavage. Here, we analyzed the role of ADAM10 in the proteolytic processing of PrP^C<it>in vivo</it>.</p> <p>Results</p> <p>Using neuron-specific <it>Adam10 </it>knockout mice, we show that ADAM10 is the sheddase of PrP^Cand that its absence <it>in vivo </it>leads to increased amounts and accumulation of PrP^Cin the early secretory pathway by affecting its posttranslational processing. Elevated PrP^Clevels do not induce apoptotic signalling via p53. Furthermore, we show that ADAM10 is not responsible for the α-cleavage of PrP^C.</p> <p>Conclusion</p> <p>Our study elucidates the proteolytic processing of PrP^Cand proves a role of ADAM10 in shedding of PrP^C<it>in vivo</it>. We suggest that ADAM10 is a mediator of PrP^Chomeostasis at the plasma membrane and, thus, might be a regulator of the multiple functions discussed for PrP^C. Furthermore, identification of ADAM10 as the sheddase of PrP^Copens the avenue to devising novel approaches for therapeutic interventions against prion diseases.</p