191 research outputs found

    The nature of multiple boron-nitrogen bonds studied using electron localization function (ELF), electron density (AIM), and natural bond orbital (NBO) methods

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    Local nature of the boron-nitrogen (BN) bonding with different formal multiplicities (B≡N, B=N, B-N) have been investigated for 25 experimentally established organoboron molecules in both real and the Hilbert space, using topological analysis of electron localization function (ELF), electron density (AIM), and natural bond orbital (NBO) method. Each BN bond has been represented (ELF) by the bonding disynaptic attractor V(B,N), with the basin electron population between 5.72e and 1.83e, confirming possible existence of all the three bond types. A covalent character of bonding can be associated with the dative mechanism due to the V(B,N) bonding basin formed mainly (91–96%) by the N electron density. Similarly, the NBO method shows 2-center natural orbitals, consisting largely of the hybrids from the N atom. The AIM analysis yields the features typical for shared (H(3,−1)(r)  0) interactions. The delocalization indices, describing electron exchanges between B and N quantum atoms, are smaller than 1.5, even for formally very short triple B≡N bonds

    A Multi Expert Decision Support Tool for the Evaluation of Advanced Wastewater Treatment Trains: A Novel Approach to Improve Urban Sustainability

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Wastewater Treatment (WWT) for water reuse applications has been accepted as a strategic solution in improving water supplies across the globe; however, there are still various challenges that should be overcome. Selection of practical solutions is then required whilst considering technical, environmental, socio-cultural, and financial factors. In this study, a multi expert decision support tool that considers a variety of evaluation criteria is proposed to provide a ranking system for competing advanced WWT technologies in terms of their performance. Two scenarios of water reuse in the contexts of Brazil and Greece are defined, and evaluation is undertaken based on opinions of water reuse experts. The results prove that the tool would successfully facilitate rigorous and methodical analysis in evaluation of WWT technologies for water reuse applications with potential for use under various sets of evaluation criteria, WWT technologies and contexts

    Flight Servicing of Robotic Refueling Mission 3

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    The Robotic Refueling Mission 3 (RRM3) payload launched aboard a SpaceX rocket en route to the International Space Station on December 5th, 2018. The Goddard Space Flight Center designed payload carried approximately 50 liters of liquid methane onboard, with a mission to demonstrate long term storage and transfer of the cryogenic fluid in microgravity. Kennedy Space Center (KSC) was tasked to design, fabricate, test, and operate a system equipped to fill an RRM3 dewar with liquid methane prior to launch. Though KSC has a rich history of fueling rockets and payloads, no such operations had previously been accomplished using liquid methane. As such, all of the hardware and processes had to be developed from scratch. The completed ground system design, along with the verification and validation testing will be outlined in this paper. Several challenges that were met and overcome during procurement of the high purity methane are described. In addition, budget restrictions prohibited fueling operations from occurring in traditional processing facilities. The unique and creative solutions which were required to maintain payload cleanliness during cryogenic servicing are also detailed

    Volumetric 18F‐FDG‐PET parameters as predictors of locoregional failure in low‐risk HPV‐related oropharyngeal cancer after definitive chemoradiation therapy

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    BackgroundWe sought to investigate the prognostic value of volumetric positron emission tomography (PET) parameters in patients with human papillomavirus (HPV)‐related oropharyngeal squamous cell carcinoma (OPSCC) and a ≀10 pack‐year smoking history treated with chemoradiation.MethodsA total of 142 patients were included. Maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG) of the primary tumor, involved regional lymph nodes, and total lesion were calculated. Cox proportional hazard modeling was used to evaluate associations of clinical and PET parameters with locoregional failure‐free survival (LRFFS), distant metastasis‐free survival (DMFS), and overall survival (OS).ResultsOn univariate analysis, volumetric PET parameters were significantly associated with all endpoints, and 8th edition American Joint Committee on Cancer/Union Internationale Contre le Cancer staging was significantly associated with DMFS and OS. On multivariate analysis, total lesion TLG was significantly associated with LRFFS, while staging was most significantly prognostic for DMFS and OS.ConclusionVolumetric PET parameters are uniquely prognostic of LRFFS in low‐risk HPV‐related OPSCC and may be useful for directing de‐intensification strategies.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147800/1/hed25505_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147800/2/hed25505.pd

    HIPK2 and extrachromosomal histone H2B are separately recruited by Aurora-B for cytokinesis

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    Cytokinesis, the final phase of cell division, is necessary to form two distinct daughter cells with correct distribution of genomic and cytoplasmic materials. Its failure provokes genetically unstable states, such as tetraploidization and polyploidization, which can contribute to tumorigenesis. Aurora-B kinase controls multiple cytokinetic events, from chromosome condensation to abscission when the midbody is severed. We have previously shown that HIPK2, a kinase involved in DNA damage response and development, localizes at the midbody and contributes to abscission by phosphorylating extrachromosomal histone H2B at Ser14. Of relevance, HIPK2-defective cells do not phosphorylate H2B and do not successfully complete cytokinesis leading to accumulation of binucleated cells, chromosomal instability, and increased tumorigenicity. However, how HIPK2 and H2B are recruited to the midbody during cytokinesis is still unknown. Here, we show that regardless of their direct (H2B) and indirect (HIPK2) binding of chromosomal DNA, both H2B and HIPK2 localize at the midbody independently of nucleic acids. Instead, by using mitotic kinase-specific inhibitors in a spatio-temporal regulated manner, we found that Aurora-B kinase activity is required to recruit both HIPK2 and H2B to the midbody. Molecular characterization showed that Aurora-B directly binds and phosphorylates H2B at Ser32 while indirectly recruits HIPK2 through the central spindle components MgcRacGAP and PRC1. Thus, among different cytokinetic functions, Aurora-B separately recruits HIPK2 and H2B to the midbody and these activities contribute to faithful cytokinesis

    Corresponding States of Structural Glass Formers

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    The variation with respect to temperature T of transport properties of 58 fragile structural glass forming liquids (68 data sets in total) are analyzed and shown to exhibit a remarkable degree of universality. In particular, super-Arrhenius behaviors of all super-cooled liquids appear to collapse to one parabola for which there is no singular behavior at any finite temperature. This behavior is bounded by an onset temperature To above which liquid transport has a much weaker temperature dependence. A similar collapse is also demonstrated, over the smaller available range, for existing numerical simulation data.Comment: 6 pages, 2 figures. Updated References, Table Values, Submitted for Publicatio

    Impact of American Joint Committee on Cancer Eighth Edition clinical stage and smoking history on oncologic outcomes in human papillomavirus‐associated oropharyngeal squamous cell carcinoma

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    BackgroundThe purpose of this study was to evaluate the AJCC eighth edition clinical staging system for human papillomavirus (HPV)‐associated oropharyngeal squamous cell carcinoma and to further understand how clinical stage and smoking history affect oncologic outcomes. The purpose of this study was to present the understanding of how clinical stage and smoking history affect oncologic outcomes in human papillomavirus (HPV)‐associated oropharyngeal squamous cell carcinoma (SCC) is critical for selecting patients for treatment deintensification.MethodsKaplan‐Meier and Cox regression were used to evaluate overall survival (OS), locoregional recurrence‐free survival (LRFS), and distant recurrence‐free survival (DRFS). Concordance statistics (C‐indices) were used to compare discriminating ability.ResultsThe OS and DRFS but not LRFS were significantly distributed using the American Joint Committee on Cancer (AJCC) seventh and eighth editions criteria. The C‐indices for OS, LRFS, and DRFS were 0.57, 0.54, and 0.60, respectively, using the AJCC seventh edition, and 0.63, 0.53, and 0.65, respectively, using the AJCC eighth edition. On multivariate analysis, 1 + pack‐year smoking history correlated with OS (hazard ratio [HR] 1.96; 95% confidence interval [CI] 1.2‐3.1; P < .01) but not LRFS or DRFS.ConclusionThese results support implementation of the AJCC eighth edition for HPV‐associated oropharyngeal SCC. Clinical stage may be more important than smoking history in selection for deintensification.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148352/1/hed25336_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148352/2/hed25336.pd
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