103 research outputs found
Experimental anonymous conference key agreement using linear cluster states
Multipartite entanglement enables secure and anonymous key exchange between
multiple parties in a network. In particular Greenberger-Horne-Zeilinger (GHZ)
states have been introduced as resource states for anonymous key exchange
protocols, in which an anonymous subset of parties within a larger network
establishes a secret key. However, the use of other types of multipartite
entanglement for such protocols remains relatively unexplored. Here we
demonstrate that linear cluster states can serve as a versatile and potentially
scalable resource in such applications. We implemented an anonymous key
exchange protocol with four photons in a linear cluster state and established a
shared key between three parties in our network. We show how to optimize the
protocol parameters to account for noise and to maximize the finite key rate
under realistic conditions. As cluster states have been established as a
flexible resource in quantum computation, we expect that our demonstration
provides a first step towards their hybrid use for networked computing and
communication
The p110 delta structure: mechanisms for selectivity and potency of new PI(3)K inhibitors.
Deregulation of the phosphoinositide-3-OH kinase (PI(3)K) pathway has been implicated in numerous pathologies including cancer, diabetes, thrombosis, rheumatoid arthritis and asthma. Recently, small-molecule and ATP-competitive PI(3)K inhibitors with a wide range of selectivities have entered clinical development. In order to understand the mechanisms underlying the isoform selectivity of these inhibitors, we developed a new expression strategy that enabled us to determine to our knowledge the first crystal structure of the catalytic subunit of the class IA PI(3)K p110 delta. Structures of this enzyme in complex with a broad panel of isoform- and pan-selective class I PI(3)K inhibitors reveal that selectivity toward p110 delta can be achieved by exploiting its conformational flexibility and the sequence diversity of active site residues that do not contact ATP. We have used these observations to rationalize and synthesize highly selective inhibitors for p110 delta with greatly improved potencies
A Phase II pilot trial to evaluate safety and efficacy of ferroquine against early Plasmodium falciparum in an induced blood-stage malaria infection study
Background: Ferroquine (SSR97193) is a candidate anti-malarial currently undergoing clinical trials for malaria. To better understand its pharmacokinetic (PK) and pharmacodynamic (PD) parameters the compound was tested in the experimentally induced blood stage malaria infection model in volunteers. Methods: Male and non-pregnant female aged 18-50 years were screened for this phase II, controlled, single-centre clinical trial. Subjects were inoculated with ~1800 viable Plasmodium falciparum 3D7A-infected human erythrocytes, and treated with a single-dose of 800 mg ferroquine. Blood samples were taken at defined time-points to measure PK and PD parameters. The blood concentration of ferroquine and its active metabolite, SSR97213, were measured on dry blood spot samples by ultra-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS). Parasitaemia and emergence of gametocytes were monitored by quantitative PCR. Safety was determined by recording adverse events and monitoring clinical laboratory assessments during the course of the study. Results: Eight subjects were enrolled into the study, inoculated with infected erythrocytes and treated with 800 mg ferroquine. Ferroquine was rapidly absorbed with maximal exposure after 4-8 and 4-12 h exposure for SSR97213. Non-compartmental PK analysis resulted in estimates for half-lives of 10.9 and 23.8 days for ferroquine and SSR97213, respectively. Parasite clearance as reported by parasite reduction ratio was 162.9 (95 % CI 141-188) corresponding to a parasite clearance half-life of 6.5 h (95 % CI: 6.4-6.7 h). PK/PD modelling resulted in a predicted minimal parasiticidal concentration of 20 ng/mL, and the single dosing tested in this study was predicted to maintain an exposure above this threshold for 454 h (37.8 days). Although ferroquine was overall well tolerated, transient elevated transaminase levels were observed in three subjects. Paracetamol was the only concomitant treatment among the two out of these three subjects that may have played a role in the elevated transaminases levels. No clinically significant ECG abnormalities were observed. Conclusions: The parameters and PK/PD model derived from this study pave the way to the further rational development of ferroquine as an anti-malarial partner drug. The safety of ferroquine has to be further explored in controlled human trials. Trial registration anzctr.org.au (registration number: ACTRN12613001040752), registered 18/09/201
Maps of Open Chromatin Guide the Functional Follow-Up of Genome-Wide Association Signals: Application to Hematological Traits
Turning genetic discoveries identified in genome-wide association (GWA) studies into biological mechanisms is an important challenge in human genetics. Many GWA signals map outside exons, suggesting that the associated variants may lie within regulatory regions. We applied the formaldehyde-assisted isolation of regulatory elements (FAIRE) method in a megakaryocytic and an erythroblastoid cell line to map active regulatory elements at known loci associated with hematological quantitative traits, coronary artery disease, and myocardial infarction. We showed that the two cell types exhibit distinct patterns of open chromatin and that cell-specific open chromatin can guide the finding of functional variants. We identified an open chromatin region at chromosome 7q22.3 in megakaryocytes but not erythroblasts, which harbors the common non-coding sequence variant rs342293 known to be associated with platelet volume and function. Resequencing of this open chromatin region in 643 individuals provided strong evidence that rs342293 is the only putative causative variant in this region. We demonstrated that the C- and G-alleles differentially bind the transcription factor EVI1 affecting PIK3CG gene expression in platelets and macrophages. A proteinâprotein interaction network including up- and down-regulated genes in Pik3cg knockout mice indicated that PIK3CG is associated with gene pathways with an established role in platelet membrane biogenesis and thrombus formation. Thus, rs342293 is the functional common variant at this locus; to the best of our knowledge this is the first such variant to be elucidated among the known platelet quantitative trait loci (QTLs). Our data suggested a molecular mechanism by which a non-coding GWA index SNP modulates platelet phenotype
Cisplatin-induced ototoxicity: the current state of ototoxicity monitoring in New Zealand.
Background: Many well-known pharmacologic agents have been shown to have toxic effects to the cochleo-vestibular system. Examples of such ototoxic agents include cisplatin and aminoglycoside antibiotics. Ototoxicity monitoring consists of a comprehensive pattern of audiological assessments designed to detect the onset of any hearing loss. Three main methods have emerged over the past decade, and include the basic audiological assessment, extended high frequency (EHF) audiometry, and otoacoustic emission (OAE) measurement. These measures can be used separately or in combination, depending on clinical purpose and patient considerations. It is suggested by the American Academy of Audiology Position Statement and Clinical Practice Guidelines: Ototoxicity Monitoring, that baseline testing be done in a fairly comprehensive manner, including pure-tone thresholds in both the conventional- and extended high frequency ranges, tympanometry, speech audiometry, and the testing of OAEs (AAA, 2009). Anecdotal evidence suggests that New Zealand Audiologists do not currently follow a national ototoxicity monitoring protocol. Therefore the main aim of this study was to explore the current status of ototoxicity monitoring within New Zealand.
Hypothesis: It was hypothesized that hospital based Audiology departments across New Zealand each followed their own internal ototoxicity monitoring protocol based, to a large extent, on the guidelines proposed by the American Academy of Audiology and by the American Speech-Language-Hearing Association.
Method: Through the use of a Telephone Interview Questionnaire, 16 charge Audiologists were interviewed to establish their current state of knowledge regarding ototoxicity monitoring at 16 out of 20 district health boards in New Zealand. Enquiries about the current systems and procedures in place at their departments together with any suggestions and recommendations to improve on these systems were made.
Results: This study found that only 9 of the 16 DHBs interviewed currently follow an ototoxicity monitoring protocol. Furthermore, other than initially hypothesized the origin of the protocols followed by the remaining 7 departments were reported to have ranged from independently developed protocols to historically adopted protocols. One department implemented an adapted version of a protocol by Fausti et al. (Ear and Hearing 1999; 20(6):497-505). This diversity in origin however, does confirm our initial suspicion that no universal and standardized monitoring protocol is currently being followed by Audiologists working in the public health sector of New Zealand
Critical success factors and analysis of internationalization strategies using the example of the product Lunchit
Eine literaturbasierte Arbeit zur Untersuchung der Erfolgsfaktoren einer Internationalisierung und der Beantwortung der Forschungsfrage âWelche sind die erfolgskritischen Faktoren einer Internationalisierung?â. Es wird jeweils ein Ăberblick ĂŒber Internationalisierungstheorien, Ziele und Motive einer Internationalisierung, Markteintrittsformen und auch Internationalisierungsstrategien gegeben. AnschlieĂend folgt die DurchfĂŒhrung eines Zielmarktvergleichs, bevor zum Abschluss der Arbeit die Internationalisierungsstrategie fĂŒr die SPENDIT AG festgelegt wird
Bundes- und Landesgesetzgebung sowie kommunale Rechtsetzung zum Klimaschutz: Welche Pflichten, welcher Handlungsbedarf und welche Handlungsmöglichkeiten ergeben sich fĂŒr Kommunen?
Die Bachelorarbeit untersucht, in welcher Art und Umfang die Kommunen im Bundes-Klimaschutzgesetz und Klimaschutzgesetz Baden-WĂŒrttemberg berĂŒcksichtigt wurden. Des Weiteren soll diese Bachelorarbeit die Kommunen im Bereich der Klimaschutzgesetzgebung durch die Ăbersicht an Pflichten, Handlungsmöglichkeiten und Handlungsbedarfe aufklĂ€ren und anhand von Empfehlungen aufzeigen, welche Handlungsschritte fĂŒr erfolgreichen kommunalen Klimaschutz unter diesen Gegebenheiten notwendig sind
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