2,640 research outputs found

    Ultraviolet relaxation dynamics in uracil: Time-resolved photoion yield studies using a laser-based thermal desorption source

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    Wavelength-dependent measurements of the RNA base uracil, undertaken with nanosecond ultraviolet laser pulses, have previously identified a fragment at m/z = 84 (corresponding to the C3H4N2O+ ion) at excitation wavelengths ≤232 nm. This has been interpreted as a possible signature of a theoretically predicted ultrafast ring-opening occurring on a neutral excited state potential energy surface. To further investigate the dynamics of this mechanism, and also the non-adiabatic dynamics operating more generally in uracil, we have used a newly built ultra-high vacuum spectrometer incorporating a laser-based thermal desorption source to perform time-resolved ion-yield measurements at pump wavelengths of 267 nm, 220 nm, and 200 nm. We also report complementary data obtained for the related species 2-thiouracil following 267 nm excitation. Where direct comparisons can be made (267 nm), our findings are in good agreement with the previously reported measurements conducted on these systems using cold molecular beams, demonstrating that the role of initial internal energy on the excited state dynamics is negligible. Our 220 nm and 200 nm data also represent the first reported ultrafast study of uracil at pump wavelengths 3(1ππ*) state. These measurements do not, however, provide any evidence for the appearance of the m/z = 84 fragment within the first few hundred picoseconds following excitation. This key finding indicates that the detection of this specific species in previous nanosecond work is not directly related to an ultrafast ring-opening process. An alternative excited state process, operating on a more extended time scale, remains an open possibility

    Is mandatory country-by-country reporting effective? - Early evidence on the economic responses by multinational firms

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    In den letzten zehn Jahren haben politische Entscheidungsträger, gemeinnützige Organisationen und die Medien wiederholt mehr Transparenz hinsichtlich der globalen Steueraktivitäten multinationaler Unternehmen gefordert. Hintergrund dieser Forderungen ist der Verdacht auf aggressive Steuerplanung seitens multinationaler Unternehmen, die beispielsweise durch ihre Präsenz in Steueroasen oder der Gewinnverlagerung in Niedrigsteuerländer beabsichtigen, ihr globales Steueraufkommen so gering wie möglich zu halten. Dementsprechend steht erhöhte Steuertransparenz ganz oben auf der politischen Agenda. Dies führte schließlich zu dem Vorschlag der OECD, die länderbezogene Berichterstattung für multinationale Unternehmen verpflichtend einzuführen, bei dem die betroffenen Unternehmen den zuständigen nationalen Steuerbehörden ihre globale Gesamtaktivität offenlegen müssen. Seit 2016 ist ein solches Country-by-Country Reporting (CbCR) für Unternehmen, die in der Europäischen Union tätig sind, gesetzlich vorgeschrieben. Während EU-Politiker das CbCR in erster Linie als Reaktion auf die als schädlich empfundenen Steuerpraktiken multinationaler Unternehmen eingeführt haben, sind die Auswirkungen einer solchen erhöhten Transparenz auf Unternehmensentscheidungen noch weitestgehend unklar. Gleichzeitig ist diese Frage aus ökonomischer und politischer Sicht höchst relevant, da Unternehmen nicht nur ihre Steuerstrategien, sondern auch ihre globalen Aktivitäten in Form von Investitionsströmen und Beschäftigung ändern könnten

    Unprofitable Affiliates and Income Shifting Behavior

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    Income shifting from high-tax to low-tax jurisdictions is considered a primary method of reducing worldwide tax burdens of multinational firms. Current losses also affect income shifting incentives. We extend prior approaches by explicitly considering unprofitable affiliates and test whether the association between losses and tax incentives for unprofitable affiliates deviates from the negative association observed in profitable affiliates. Results suggest that multinational firms alter the distribution of reported profits to take advantage of losses. Our point estimate for profitable affiliates implies that an increase of one standard deviation in the tax incentive, C, of an affiliate with an average return on assets of 13.3 is associated with a lower return on assets of 0.5 percentage points. The same change in tax incentive of an unprofitable affiliate is associated with an increase in its return on assets of approximately 0.7 percentage points, holding assets, labor, productivity, and other factors constant. We further document a larger responsiveness to tax incentives between profitable and unprofitable affiliates in high-tax jurisdictions, consistent with predictions.McCombs Research Excellence Fund || McCombs Supply Chain Management Center of Excellence || Social Sciences and Humanities Research Council of Canad

    Probing the dynamic stalk region of the ribosome using solution NMR

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    Abstract: We describe an NMR approach based on the measurement of residual dipolar couplings (RDCs) to probe the structural and motional properties of the dynamic regions of the ribosome. Alignment of intact 70S ribosomes in filamentous bacteriophage enabled measurement of RDCs in the mobile C-terminal domain (CTD) of the stalk protein bL12. A structural refinement of this domain using the observed RDCs did not show large changes relative to the isolated protein in the absence of the ribosome, and we also found that alignment of the CTD was almost independent of the presence of the core ribosome particle, indicating that the inter-domain linker has significant flexibility. The nature of this linker was subsequently probed in more detail using a paramagnetic alignment strategy, which revealed partial propagation of alignment between neighbouring domains, providing direct experimental validation of a structural ensemble previously derived from SAXS and NMR relaxation measurements. Our results demonstrate the prospect of better characterising dynamical and functional regions of more challenging macromolecular machines and systems, for example ribosome–nascent chain complexes

    Eleven-year experience with the avidin-biotin pretargeting system in glioblastoma: Toxicity, efficacy and survival

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    Background: The 3-step avidin-biotin pretargeting approach is applied in patients with recurrent glioblastoma (GBM), using biotinylated anti-tenascin monoclonal antibody as the first step of pretargeting followed by avidin and 90Ybiotin. Methods: The present study reviews objective response and overall survival rates in 502 glioblastoma patients treated with 3-step radioimmunotherapy in our institute from December 1994 to December 2005. Patients underwent standard treatment before receiving Pretargeted Antibody-Guided Radionuclide Therapy with 90Y-biotin (PAGRIT ®). Results: Of the 502 patients, 272 (54%) were evaluable for response and 375 (75%) for overall survival. 174 patients (64%) continued to progress after PAGRIT ®, 77 (28%) obtained disease stabilization, and 21 (8%) showed objective tumor regression. Survival of the 375 evaluable patients was 98.4% at 6 months, 79.2% at 12 months, 51.7% at 18 months, and 30.7% at 24 months after the first cycle of PAGRIT ®. All 375 received 3-step PAGRIT ® at recurrence of GBM. The median survival time from diagnosis was 19 months. Conclusion: The results from this retrospective analysis suggest that 90Y-biotin PAGRIT ® interferes with the progression of glioblastoma, prolonging survival in a larger number of patients. Our analysis forms the basis for further prospective trials, where radioimmunotherapy, which is known to be more effective in minimal residual disease, could be offered immediately after surgery. © Grana et al.; Licensee Bentham Open

    A Cross-European Study of Informal Carers’ Needs in the Context of Caring for Older People, and their Experiences with Professionals Working in Integrated Care Settings

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    Introduction: Informal carers are increasingly relied on for support by older people and the health and social care systems that serve them. It is therefore important that health and social care professionals are knowledgeable about and responsive to informal carers’ needs. This study explores informal carers’ own needs within the context of caregiving; and examines, from the informal carers’ perspective, the extent to which professionals assess, understand and are responsive to informal carers’ needs

    Biallelic mutations in DYNC2LI1 are a rare cause of Ellis-van Creveld syndrome

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    Ellis van Creveld syndrome (EvC) is a chondral and ectodermal dysplasia caused by biallelic mutations in the EVC, EVC2 and WDR35 genes. A proportion of cases with clinical diagnosis of EvC, however, do not carry mutations in these genes. To identify the genetic cause of EvC in a cohort of mutation-negative patients, exome sequencing was undertaken in a family with three affected members, and mutation scanning of a panel of clinically and functionally relevant genes was performed in 24 additional subjects with features fitting/overlapping EvC. Compound heterozygosity for the c.2T>C (p.Met1?) and c.662C>T (p.Thr221Ile) variants in DYNC2LI1, which encodes a component of the intraflagellar transport-related dynein-2 complex previously found mutated in other short-rib thoracic dysplasias, was identified in the three affected members of the first family. Targeted resequencing detected compound heterozygosity for the same missense variant and a frameshift change (p.Val141*) in two siblings with EvC from a second family, while a newborn with a more severe phenotype carried two DYNC2LI1 truncating variants. Our findings indicate that DYNC2LI1 mutations are associated with a wider clinical spectrum than previously appreciated, including EvC, with the severity of the phenotype likely depending on the extent of defective DYNC2LI1 function

    Generation and in vivo validation of an IL-12 fusion protein based on a novel anti-human FAP monoclonal antibody

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    BACKGROUND In this study, we describe the generation of a fully human monoclonal antibody (named '7NP2') targeting human fibroblast activation protein (FAP), an antigen expressed in the microenvironment of different types of solid neoplasms. METHODS 7NP2 was isolated from a synthetic antibody phage display library and was improved by one round of mutagenesis-based affinity maturation. The tumor recognition properties of the antibody were validated by immunofluorescence procedures performed on cancer biopsies from human patients. A fusion protein consisting of the 7NP2 antibody linked to interleukin (IL)-12 was generated and the anticancer activity of the murine surrogate product (named mIL12-7NP2) was evaluated in mouse models. Furthermore, the safety of the fully human product (named IL12-7NP2) was evaluated in Cynomolgus monkeys. RESULTS Biodistribution analysis in tumor-bearing mice confirmed the ability of the product to selectively localize to solid tumors while sparing healthy organs. Encouraged by these results, therapy studies were conducted in vivo, showing a potent antitumor activity in immunocompetent and immunodeficient mouse models of cancer, both as single agent and in combination with immune checkpoint inhibitors. The fully human product was tolerated when administered to non-human primates. CONCLUSIONS The results obtained in this work provided a rationale for future clinical translation activities using IL12-7NP2

    Putative adverse outcome pathways for female reproductive disorders to improve testing and regulation of chemicals

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    Modern living challenges female reproductive health. We are witnessing a rise in reproductive disorders and drop in birth rates across the world. The reasons for these manifestations are multifaceted and most likely include continuous exposure to an ever-increasing number of chemicals. The cause-effect relationships between chemical exposure and female reproductive disorders, however, have proven problematic to determine. This has made it difficult to assess the risks chemical exposures pose to a woman's reproductive development and function. To address this challenge, this review uses the adverse outcome pathway (AOP) concept to summarize current knowledge about how chemical exposure can affect female reproductive health. We have a special focus on effects on the ovaries, since they are essential for lifelong reproductive health in women, being the source of both oocytes and several reproductive hormones, including sex steroids. The AOP framework is widely accepted as a new tool for toxicological safety assessment that enables better use of mechanistic knowledge for regulatory purposes. AOPs equip assessors and regulators with a pragmatic network of linear cause-effect relationships, enabling the use of a wider range of test method data in chemical risk assessment and regulation. Based on current knowledge, we propose ten putative AOPs relevant for female reproductive disorders that can be further elaborated and potentially be included in the AOPwiki. This effort is an important step towards better safeguarding the reproductive health of all girls and women.Peer reviewe
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