357 research outputs found

    Exit Strategies of Venture Capitalists in Hot Issue Markets: Evidence from the “Neuer Markt in Germany

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    In this study we analyze the IPO exit behavior of venture capitalists (VCs) in the Neuer Markt, the former market for young growth companies in Germany. We find empirical evidence that VCs were able to time their exit quite successfully in the primary market and to some extent also in the secondary market. The larger the number of shares being sold by the VCs at the IPO date, the lower is the IPO performance after expiration of the lock-up period. In addition, the firms that went public in the year 2000 planned their IPO too late in the stock market cycle so that--due to the mandatory lock-up period of six months--some VCs had no chance for a lucrative exit and still owned shares three years after the IPO. Thus, lock-up commitments can be quite costly for early investors particularly towards the end of a hot issue market

    Continuous Noninvasive Monitoring of Lung Recruitment during High-Frequency Oscillatory Ventilation by Electrical Impedance Measurement: An Animal Study

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    Background: Ventilatory pressures should target the range between the upper and lower inflection point of the pressure volume curve in order to avoid atelecto- and volutrauma. During high-frequency oscillatory ventilation (HFOV), this range is difficult to determine. Quadrant impedance measurement (QIM) has recently been shown to allow accurate and precise measurement of lung volume changes during conventional mechanical ventilation. Objectives: To investigate if QIM can be used to determine a static pressure-residual impedance curve during a recruitment-derecruitment manoeuvre on HFOV and to monitor the time course of alveolar recruitment after changing mean airway pressure (MAP). Methods: An incremental and decremental MAP trial (6 cm H₂O to 27 cm H₂O) was conducted in five surfactantdepleted newborn piglets during HFOV. Ventilatory, gas exchange and haemodynamic parameters were recorded. Continuous measurement of thoracic impedance change was performed. Results: Mean residual impedance (RI) increased with each stepwise increase of MAP resulting in a total mean increase of +26.5% (±4.0) at the highest MAP (27 cm H₂O) compared to baseline ventilation at 6 cm H₂O. Upon decreasing MAP levels, RI fell more slowly compared to its ascent; 83.4% (±19.1) and 84.8% (±16.4) of impedance changes occurred in the first 5 min after an increase or decrease in airway pressure, respectively. Conclusions: QIM could be used for continuous monitoring of thoracic impedance and determination of the pressure-RI curve during HFOV. The method could prove to be a promising bedside method for the monitoring of lung recruitment during HFOV in the future

    The virome ofGerman bats: comparing virus discovery approaches

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    Bats are known to be reservoirs of several highly pathogenic viruses. Hence, the interest in bat virus discovery has been increasing rapidly over the last decade. So far, most studies have focused on a single type of virus detection method, either PCR, virus isolation or virome sequencing. Here we present a comprehensive approach in virus discovery, using all three discovery methods on samples from the same bats. By family-specific PCR screening we found sequences of paramyxoviruses, adenoviruses, herpesviruses and one coronavirus. By cell culture we isolated a novel bat adenovirus and bat orthoreovirus. Virome sequencing revealed viral sequences of ten different virus families and orders: three bat nairoviruses, three phenuiviruses, one orbivirus, one rotavirus, one orthoreovirus, one mononegavirus, five parvoviruses, seven picornaviruses, three retroviruses, one totivirus and two thymoviruses were discovered. Of all viruses identified by family-specific PCR in the original samples, none was found by metagenomic sequencing. Vice versa, none of the viruses found by the metagenomic virome approach was detected by family-specific PCRs targeting the same family. The discrepancy of detected viruses by different detection approaches suggests that a combined approach using different detection methods is necessary for virus discovery studies.Peer Reviewe

    A novel Coltivirus-related virus isolated from free-tailed bats from Cîte d’Ivoire is able to infect human cells in vitro

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    Background: Zoonotic transmission events play a major role in the emergence of novel diseases. While such events are virtually impossible to predict, wildlife screening for potential emerging pathogens can be a first step. Driven by recent disease epidemics like severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and Ebola, bats have gained special interest as reservoirs of emerging viruses. Methods: As part of a bigger study investigating pathogens in African bats we screened animals for the presence of known and unknown viruses. Results: We isolated and characterised a novel reovirus from blood of free-tailed bats (Chaereophon aloysiisabaudiae) captured in 2006 in Cîte d’Ivoire. The virus showed closest relationship with two human pathogenic viruses, Colorado tick fever virus and Eyach virus, and was able to infect various human cell lines in vitro. Conclusion: The study shows the presence of a coltivirus-related virus in bats from Sub-Sahara Africa. Serological studies could help to assess its impact on humans or wildlife health

    One-step selection of Vaccinia virus-binding DNA aptamers by MonoLEX

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    <p>Abstract</p> <p>Background</p> <p>As a new class of therapeutic and diagnostic reagents, more than fifteen years ago RNA and DNA aptamers were identified as binding molecules to numerous small compounds, proteins and rarely even to complete pathogen particles. Most aptamers were isolated from complex libraries of synthetic nucleic acids by a process termed SELEX based on several selection and amplification steps. Here we report the application of a new one-step selection method (MonoLEX) to acquire high-affinity DNA aptamers binding Vaccinia virus used as a model organism for complex target structures.</p> <p>Results</p> <p>The selection against complete Vaccinia virus particles resulted in a 64-base DNA aptamer specifically binding to orthopoxviruses as validated by dot blot analysis, Surface Plasmon Resonance, Fluorescence Correlation Spectroscopy and real-time PCR, following an aptamer blotting assay. The same oligonucleotide showed the ability to inhibit <it>in vitro </it>infection of Vaccinia virus and other orthopoxviruses in a concentration-dependent manner.</p> <p>Conclusion</p> <p>The MonoLEX method is a straightforward procedure as demonstrated here for the identification of a high-affinity DNA aptamer binding Vaccinia virus. MonoLEX comprises a single affinity chromatography step, followed by subsequent physical segmentation of the affinity resin and a single final PCR amplification step of bound aptamers. Therefore, this procedure improves the selection of high affinity aptamers by reducing the competition between aptamers of different affinities during the PCR step, indicating an advantage for the single-round MonoLEX method.</p

    Preventative ibandronate treatment has the most beneficial effect on the microstructure of bone in experimental tumor osteolysis

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    We investigated the effect of ibandronate on three-dimensional (3-D) microstructure and bone mass in experimentally induced tumor osteolysis. Walker carcinosarcoma cells were implanted into the left femur of female rats that received 26-day ibandronate pretreatment followed by continued therapy or ibandronate posttreatment only. A tumor-only group received isotonic saline. At endpoint, excised femurs were scanned using microcomputed tomography (ÎŒCT) to assess bone volume density, bone mineral content, trabecular number/thickness, and separation for cortical plus trabecular bone or trabecular bone alone. Compared with the nonimplanted right femur, bone volume and surface density and trabecular number and thickness were reduced in the distal left femur following tumor cell implantation. ÎŒCT analysis revealed greater cortical and trabecular bone mineral content in the preventative and interventional (pre-post tumor) ibandronate group, and the interventional (post-tumor) ibandronate group, versus the tumor-only group. Bone volume density was significantly higher in pre-post and post-tumor groups compared to the tumor-only group. After preventative and interventional ibandronate, bone volume density and trabecular thickness were 13% and 60% greater, respectively, than in the post-tumor treatment group. 3-D ÎŒCT images confirmed microstructural changes. We conclude that combined interventional and preventative ibandronate preserves bone strength and integrity more than intervention alon
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