cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Formation of Low-Mass X-ray Binaries. I. Constraints on Hydrogen-Rich Donors at the Onset of the X-ray Phase
Creators: name: Kalogera, Vassiliki
name: Webbink, Ronald F.
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We identify and quantify the set of constraints that neutron star-normal star binaries must satisfy in order to become observable LMXBs. These constraints are related to (i) the thermal and hydrostatic equilibrium of the donors, (ii) the degree to which the mass transfer process is conservative, and (iii) the age of the systems. They divide the parameter space of potential LMXBs in several distinct parts, of which those that actually become LMXBs at the onset of mass transfer occupy only a small part. Of the remainder, many become unstable to dynamical time scale mass transfer either at the onset or later in the course of mass transfer, and enter common envelope evolution. Others experience super-Eddington mass transfer but may eventually survive to become LMXBs. These survivors arguably include binary millisecond pulsars with orbital periods in excess of $100$\,d, ultrashort-period LMXBs with hydrogen-deficient donors, and long-period LMXBs with giant donors.
description: 12 pages (text) and 10 Postscript figures, total of 11 PS files all in one uuencoded gz-compressed tar file. Accepted for publication in ApJ. In case of problems, contact vicky@astro.uiuc.edu
Global Properties of Multiple Merger Remnants
Creators: name: Weil, Melinda L.
name: Hernquist, Lars
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Merger remnants of small groups of galaxies are contrasted with relics of mergers of pairs of galaxies to determine which process produces objects that best compare to real ellipticals. In both cases, the progenitors consist of self-gravitating disks, halos, and, sometimes, bulges. Pairs of galaxies merge from orbits that initially have zero--energy. The systems that produce multiple merger remnants are dense, six--member groups in virial equilibrium with low velocity dispersions. Multiple and pair mergers produce remnants which differ in both their spatial and kinematic properties. Multiple merger remnants have small triaxialities and are most likely to appear nearly round from most viewing angles. They possess cores, with sizes of a few tenths of an effective radius, that are more extended than pair remnant cores, even when bulges are included in the progenitors. In multiple mergers, the spin of all components -- halo, disk, and bulge -- increases and, while velocity dispersion dominates in the central regions, $v_r/σ\approx 1$ outside an effective radius in some projections. The angular momentum and minor axis vectors are aligned for multiple merger remnants. During merging of multiple progenitors, about half of the orbital angular momentum in each luminous component is converted into internal rotation in that component. Material is prevented from accumulating in the center of multiple merger remnants as efficiently as it does in pair mergers. In pair mergers that include gas, unrealistically steep surface brightness profiles have been produced in center of the remnants; in multiple mergers the formation of overdense nuclei may be impeded, thus allowing more successful comparison with real elliptical galaxies.
description: 43 pages of uuencoded compressed postscript with 17 figures. Postscript figures 1,2,3,17, 3Mb total, available upon request from weil@ucolick.org. Accepted to the Astrophysical Journal
Precision ultrasound sensing on a chip
Creators: name: Basiri-Esfahani, Sahar
name: Armin, Ardalan
name: Forstner, Stefan
name: Bowen, Warwick P.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Quantum Physics (quant-ph)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Ultrasound sensors have wide applications across science and technology. However, improved sensitivity is required for both miniaturisation and increased spatial resolution. Here, we introduce cavity optomechanical ultrasound sensing, where dual optical and mechanical resonances enhance the ultrasound signal. We achieve noise equivalent pressures of 8--300 $μ$Pa/$\sqrt{\rm Hz}$ at kilohertz to megahertz frequencies in a microscale silicon-chip-based sensor with $>$120 dB dynamic range. The sensitivity far exceeds similar sensors that use optical resonance alone and, normalised to sensing area, surpasses previous air-coupled ultrasound sensors by several orders of magnitude. The noise floor is, for the first time, dominated by collisions from molecules in the gas within which the acoustic wave propagates. This new approach to acoustic sensing could find applications ranging from biomedical diagnostics, to autonomous navigation, trace gas sensing, and scientific exploration of the life-induced-vibrations of single cells.
description: 50 pages, 15 figures
Coadjoint orbits of Lie algebras and Cartan class
Creators: name: Goze, Michel
name: Remm, Elisabeth
Publisher: name: arXiv
Year: 2018
Subjects: subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 17Bxx, 53D10, 53D05

description: We study the coadjoint orbits of a Lie algebra in terms of Cartan class. In fact, the tangent space to a coadjoint orbit $\mathcal{O}(α)$ at the point $α$ corresponds to the characteristic space associated to the left invariant form;$α$ and its dimension is the even part of the Cartan class of $α$. We apply this remark to determine Lie algebras such that all the nontrivial orbits (nonreduced to a point) have the same dimension, in particular when this dimension is 2 or 4. We determine also the Lie algebras of dimension $2n$ or $2n+1$ having an orbit of dimension $2n$.
description: 20 pages
3D silica-gelatin hybrid scaffolds for tissue regeneration
Creators: name: Nelson, Maria
Publisher: name: Imperial College London
Year: 2016

description: Cartilage defects affect millions of people worldwide however current treatment options do not provide the zonal organisation required to regenerate healthy hyaline cartilage. In particular, the regeneration of high density ECM and cells is required to provide the articular surface of the tissue. Developments in tissue scaffolds have typically focused on synthetic polymers with low bioactivity due to their ease of processing. Here, the silica-gelatin sol-gel hybrid system was further developed for 3D printing and electrospinning to generate a zonal, bioactive scaffold. GPTMS, (3-glycidyloxypropyl)trimethoxysilane, was used to couple the silicate network and gelatin molecules. A modified hybrid method was required to avoid rapid gelation but retain high levels of crosslinking and sol-gel network condensation. To produce the material, the gelatin and GPTMS were mixed for 3 h and 3D printed scaffolds were aged for 1 week at room temperature. The hybrid composition most compatible with the 3D printing process had a 78:22, gelatin to TEOS mass ratio, and C-factor of 500 (molar ratio of GPTMS to gelatin). When 3D printing the gels, a minimum strut separation of 1 mm was achievable. To dry the 3D printed scaffolds, freeze drying and critical point drying resulted in very different structures. Freeze drying produced very thin, <40 μm struts, and large ~700 μm channels. Critical point drying produced ~160 μm struts and ~200 μm channels which falls within the range hypothesised to be suitable for cartilage regeneration. Electrospinning required further adjustments to the hybrid method to improve the volatility of the solvent. Conformable cotton wool-like fibres with ~1.5 μm diameter were achieved using a 70:30 gelatin to TEOS mass ratio. The C-factors used: 250, 500, and 750, resulted in increasing silica network condensation: 64.3 %, 75.5 %, and 81.1 % respectively. To create the cotton wool-like fibre structure, hybrid solutions with 60-80 cP viscosity were electrospun in 55 % humidity and dried without contacting each other or the collector surface. Both 3D printed and electrospun fibres showed promising dissolution results. The structures were maintained as only ~3 % gelatin was released over a one month study (3D printed) and ~2 %gelatin over a one week study (fibres). The silicon release was ~25 % of the silica content for 3D printed scaffolds, and ~13 % for fibres (CF500 and CF750). The silica-gelatin hybrids were biocompatible and provided native attachment sites for both osteoblasts and chondrocytes. Over 28-days, chondrocytes appeared to regenerate uniform density hyaline cartilage throughout the 3D printed scaffolds in vitro.
Unifying size-topology relations in random packings of dry adhesive polydisperse spheres
Creators: name: Liu, Wenwei
name: Chen, Sheng
name: Wu, Chuan-yu
name: Li, Shuiqing
Publisher: name: arXiv
Year: 2018
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study the size-topology relations in random packings of dry adhesive polydisperse microspheres with Gaussian and lognormal size distributions through a geometric tessellation. We find that the dependence of the neighbour number on the centric particle size is always quasilinear, independent of the size distribution, the size span or interparticle adhesion. The average local packing fraction as a function of normalized particle size for different size variances is well regressed on the same profile, which grows to larger values as the relative strength of adhesion decreases. As for the local coordination number-particle size profiles, they converge onto a single curve for all the adhesive particles, but will gradually transfer to another branch for non-adhesive particles. Such adhesion induced size-topology relations are interpreted theoretically by a modified geometrical "granocentric" model, where the model parameters are dependent on a dimensionless adhesion number. Our findings, together with the modified theory, provide a more unified perspective on the substantial geometry of amorphous polydisperse systems, especially those with fairly loose structures.
description: 8 pages, 7 figures
Introduction of an alternative carbon fixation cycle into Synechocystis sp. PCC 6803
Creators: name: Cotton, Charles
Publisher: name: Imperial College London
Year: 2016

description: The aim of thesis was to replace the carbon-fixing Calvin cycle of Synechocystis sp. PCC 6803 with the 3-hydroxypropionate bi-cycle. A genome-scale metabolic model was made to test how integration of the 3-hydroxypropionate bi-cycle into the cyanobacterial cell might affect growth and central metabolism. Two separate approaches for knocking out the Calvin cycle were tested, by deleting either the phosphoribulokinase gene or replacing the RuBisCO operon with a metabolic bypass. The first DNA constructs for expression of all enzymes in the bi-cycle were made and introduced into Synechocystis sp. PCC 6803, although expression of proteins other than the malonyl-CoA reductase and propionyl-CoA synthase was not detected. Several enzymes of the bi-cycle were cloned and expressed in Escherichia coli for characterisation and protein crystallisation studies. The structure of the native state of the tri-functional malyl-CoA lyase involved in the 3-hydroxypropionate bi-cycle was solved. The efforts made in these studies should prove useful for the successful engineering of the remainder of the 3-hydroxypropionate bi-cycle into Synechocystis sp. PCC 6803.
Sustainability assessment of biochar - evaluating the potential environmental, economic and social impacts of the production and application of biochar in Europe as an option for climate change mitigation
Creators: name: Rack, Mireille
Publisher: name: Imperial College London
Year: 2017

description: Sustainable development and climate change are at the forefront of today’s political agendas, as signified by the 2016 Paris Agreement and the 2015 United Nations’ Sustainable Development Goals. Carbon Dioxide Removal (CDR) technologies are being investigated for their contribution to reducing atmospheric greenhouse gas levels. The PhD assesses the potential of biochar systems as a sustainable CDR technology for climate change mitigation at a European scale. The potential sustainability impacts of biochar production and land application are evaluated by applying life cycle approaches to analyse the environmental, economic and social impacts within the overarching Life Cycle Sustainability Assessment (LCSA) framework. Scenario modelling is incorporated to estimate feedstock potentials and the scale of biochar production within Europe, as well as the corresponding levels of carbon sequestration. The research results indicate that gasification biochar systems have potential as CDR technologies, though the uncertainty regarding biochar’s stable carbon fraction remains a significant knowledge gap. The use of ‘wastes’ as the input material is more likely to reduce potential negative impacts in all three sustainability components. Though overall, the current economic climate limits the feasibility of sustainable biochar systems. The results are sensitive to the modelling approach, especially the incorporation of ‘consequential’ elements, which was shown to significantly benefit the outcomes of the environmental and economic assessments. The scenario modelling outputs suggest that large-scale implementation of biochar systems within Europe can contribute an important share of the EU emission reduction targets. However, to incentivise the uptake of biochar and/or to generate policy support, further certainty and evidence of biochar’s impacts following land application is needed. Overall, a single-issue focus is no longer applicable in today’s policy climate. It is important to assess all three pillars of sustainability when evaluating whether a product system/process is capable of contributing to sustainable development. The novel LCSA framework shows potential to assist with such assessments at the micro-level.
A new faint Type Ia Supernova: SN 1997cn in NGC 5490
Creators: name: Turatto, M.
name: Piemonte, A.
name: Benetti, S.
name: Cappellaro, E.
name: Mazzali, P. M.
name: Danziger, I. J.
name: Patat, F.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Observations of the recent SN 1991bg in the elliptical galaxy NGC 5490 show that this objects closely resembles, both photometrically and spectroscopically, the faint SNIa 1991bg. The two objects have similar light curves, which do not show secondary maxima in the near IR as normal type Ia supernovae. The host galaxy, NGC5490, lies in the Hubble flow. Adopting for SN1997cn a reddening E(B-V)=0, the absolute magnitude is faint: MV = -17.98 using Ho=65 and MV = -17.40 using Ho=85 km/(s Mpc). The latter value is in close agreement with the absolute magnitude of SN 1991bg on the SBF--PNLF--TF distance scale. The photospheric spectra of the two SNe show the same peculiarities, the deep TiII trough between 4000 and 4500A, the strong CaII IR triplet, the narrow absorption at about 5700A and the slow expansion velocity. In analogy to SN 1991bg the observed spectrum of SN1997cn has been successfully modeled by scaling down the W7 model by a factor of 2, assuming a rise time to B maximum of 18 days, a photospheric velocity and an effective temperature low compared to normal SNIa. The influence of the distance scale adopted on the input parameters of the best fit model is also discussed. These data demonstrate that peculiar SNIa like SN 1991bg are not once--in--a--lifetime events and that deep SN searches can be contaminated by underluminous SN Ia in a fairly large volume.
description: accepted for Astron.; J. 6 figures
Lognormal Properties of SGR 1806-20 and Implications for Other SGR Sources
Creators: name: Hurley, K. J.
name: McBreen, B.
name: Delaney, M.
name: Britton, A.
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The time interval between successive bursts from SGR 1806-20 and the intensity of these bursts are both consistent with lognormal distributions. Monte Carlo simulations of lognormal burst models with a range of distribution parameters have been investigated. The main conclusions are that while most sources like SGR 1806-20 should be detected in a time interval of 25 years, sources with means about 100 times longer have a probability of about 5\% of being detected in the same interval. A new breed of experiments that operate for long periods are required to search for sources with mean recurrence intervals much longer than SGR 1806-20.
description: 4 pages, latex with seperate file containing 2 uuencoded, gzip'ed, tarred, .eps figures. Replaced with file that does not use kluwer.sty to allow automatic postscript generation. To appear in proceedings of ESLAB 29
Eqvus Linnaeus, 1758, gen. nov.
Creators: name: Linnaeus, Carolus
Publisher: name: Laurentius Salvius
Year: 1758
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Perissodactyla
Equidae
Eqvus

description: Eqvus [gen. nov.]
Dentes Primores superiores VI ere- cto-paralleli.
Inferiores VI prominentiores.
Laniarii solitarii, inclusi, utrinque remoti.
Pedes ungula indivisa.
description: Published as part of Linnaeus, Carolus, 1758, Systema Naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, Stockholm :Laurentius Salvius on page 73, DOI: 10.5962/bhl.title.542, http://zenodo.org/record/3922206
Ultrafast Transient Dynamics of Adsorbates on Surfaces Deciphered: The Case of CO on Cu(100)
Creators: name: Novko, D.
name: Tremblay, J. C.
name: Alducin, M.
name: Juaristi, J. I.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Time-resolved vibrational spectroscopy constitutes an invaluable experimental tool for monitoring hot-carrier induced surface reactions. However, the absence of a full understanding on the precise microscopic mechanisms causing the transient spectral changes has been limiting its applicability. Here we introduce a robust first-principles theoretical framework that successfully explains both the nonthermal frequency and linewidth changes of the CO internal stretch mode on Cu(100) induced by femtosecond laser pulses. Two distinct processes engender the changes: electron-hole pair excitations underlie the nonthermal frequency shifts, while electron-mediated vibrational mode coupling gives rise to linewidth changes. Furthermore, the origin and precise sequence of coupling events are finally identified.
description: Article as accepted for publication in Physical Review Letters; 5 pages, 2 figures, 1 table
Second-order dual fermion approach to the Mott transition in the two-dimensional Hubbard model
Creators: name: van Loon, Erik G. C. P.
name: Katsnelson, Mikhail I.
name: Hafermann, Hartmut
Publisher: name: arXiv
Year: 2018
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We apply the dual fermion approach with a second-order approximation to the self-energy to the Mott transition in the two-dimensional Hubbard model. The approximation captures nonlocal dynamical short-range correlations as well as several features observed in studies using cluster dynamical mean-field theory. This includes a strong reduction of the critical interaction and inversion of the slope of the transition lines with respect to single-site dynamical mean-field theory. We show that these effects coincide with a much smaller momentum differentiation compared to cluster methods. We further discuss the role of the self-consistency condition and show that the approximation behaves as an asymptotic series at low temperature.
description: 11 pages, 12 figures
Influence of novel carrier Soluplus® on aqueous stability, oral bioavailability, and anticancer activity of Morin hydrate
Creators: name: Abhijeet D. Kulkarni
name: Belgamwar, Veena S.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Biochemistry
subject: Cell Biology
subject: Pharmacology
subject: Biotechnology
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine

description: Present work demonstrated the influence of novel amphiphilic carrier Soluplus® on the solubility and oral bioavailability of Morin hydrate (MOR). Spray-dried solid dispersions (SSD) were developed using the design of experiment (DoE). Saturation solubility study of the optimized formulation SSD F(7) showed many fold increment in the solubility with acceptable aqueous stability. In vitro drug diffusion kinetics suggested Weibull model to be the best fit. In vitro cytotoxicity assay revealed a significant increase in the anticancer potential compared to innate MOR. Furthermore, SSD F(7) showed 2.27-fold enhancement in the relative bioavailability as compared to MOR. BCS: biopharmaceutical classification system; MOR: Morin hydrate; SD: solid dispersion; SSD: spray dried solid dispersion; PM: physical mixture; CCD: central composite design; PSD: particle size distribution; PDI: polydispersity index; SEM: scanning electron microscopy; XRD: X-ray diffraction; DSC: differential scanning calorimetry; TGA: thermal gravimetric analysis; DTA: differential thermal analysis; DTG: derivative thermogravimetry; Tg: glass transition temperature; API: active pharmaceutical ingredient; P-gp: permeability glycoprotein; SRB: sulforhodamine B; ADR: adriamycin; DoE: design of experiment
Investigating the requirements for secondary use of data to drive improvement in the quality and safety of medication use
Creators: name: Chaudhry, Navila Talib
Publisher: name: Imperial College London
Year: 2016

description: The increase in implementation of electronic prescribing (EP) systems in secondary care and the use of electronic hospital pharmacy (EHP) systems provide considerable opportunities for reusing routinely collected data to support quality improvement work around medication safety. In previous literature, secondary use of data (SUD) has been explored in a fragmentary manner and considerable scope existed for applied research to guide users and developers in this area. This PhD sought to address those gaps by employing mixed methods and the aims were to investigate SUD requirements for effective quality monitoring and feedback processes to ensure improvement in the quality and safety of medication use, and to enhance the value of EP and EHP systems for users. This PhD provides a systematic narrative review on the current evidence base available on SUD interventions in practice. Mixed methods were used to expand upon the process of SUD, the factors influencing it, the current reuses of data in practice, how individuals define SUD, and the reasons and types of data currently being reused from EP and/or EHP systems within England. There were complexities in defining SUD; however, a definition was formed by collating the previous evidence base with the qualitative findings of this PhD. The national survey revealed various cases of SUD and that a time lag existed between EP implementation and SUD. The mixed methods identified different levels of SUD that existed: reuse of data to identify a gap for improvement, reuse of data to evaluate interventions, and reuse of data driving improvement (as an intervention). The findings of the empirical work within this PhD built upon one another to produce and validate a SUD framework that allows: stakeholders to enhance application of SUD locally in secondary care, to enhance transparency of SUD interventions, and overcome barriers and consider factors influencing SUD.
Combination of anti-cancer drug therapy with targeted gene therapy against glioblastoma.
Creators: name: Przystal, Justyna
Publisher: name: Imperial College London
Year: 2016

description: Glioblastoma multiforme (GBM) is the most aggressive and resistant to common therapies primary brain cancer in adults with extremely low percentage of survivors. Therefore, novel therapeutic approaches are greatly needed for these patients. Gene therapy can be a useful adjuvant to conventional therapies such as radiotherapy and chemotherapy. In the past twenty years, numerous gene delivery strategies for cancer, and glioblastoma in particular, have been developed with increasing number of models reaching clinical trials. However, the blood-brain barrier (BBB) is a major obstacle in accessing and treating brain tumours through systemic administration. Work from our laboratory has shown the great potential of a double-targeted Adeno-associated virus/Phage (AAVP) hybrid vector under Glucose-regulated protein 78 promoter (Grp78) (RGD4C/Grp78-AAVP) in targeted systemic cancer gene therapy. Here we investigated the response to combination therapy with suicide gene therapy using Herpes Simplex Virus thymidine kinase (HSVtk) and temozolomide (TMZ). Using a proliferation assay and flow cytometry techniques we demonstrated that RGD4C/Grp78-HSVtk vector mediated stronger cell death in combination with ganciclovir (GCV) and temozolomide than the combination therapy with RGD4C/CMV-HSVtk vector and each therapy alone. Moreover, we showed that temozolomide increases endogenous Grp78 promoter activity and boosts transgene expression mediated by RGD4C/Grp78-AVVP. Also, we demonstrated that RGD4C/Grp78-AAVP vector crosses blood-brain barrier and targets intracranial tumours in mice. Finally, we showed that systemic administration of RGD4C/Grp78-HSVtk and TMZ induces regression of brain tumours in mice. Another approach of targeted therapy for human cancer involves the depletion of key amino acids required for tumours to proliferate e.g. arginine. Recent in vitro studies showed that GBMs lacking argininosuccinate synthetase (ASS) expression are sensitive to arginine depleting enzymes such as arginine deiminase (ADI). In our studies we used a pegylated form of arginine deiminase (ADI-PEG20), to target ASS-negative tumours. We found that ADI-PEG20 can inhibit the growth of ASS-negative glioblastoma tumours in mice. Together, our data demonstrate novel therapeutic strategies against glioblastoma which overcome the limitations imposed by the blood-brain barrier.
Effect of venting range hood flow rate on size-resolved ultrafine particle concentrations from gas stove cooking
Creators: name: Sun, Liu
name: Wallace, Lance A.
name: Dobbin, Nina A.
name: Hongyu You
name: Kulka, Ryan
name: Shin, Tim
name: St-Jean, Melissa
name: Aubin, Daniel
name: Singer, Brett C.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biophysics
subject: Space Science
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Biotechnology
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: Cancer
subject: 60506 Virology

description: Cooking is the main source of ultrafine particles (UFP) in homes. This study investigated the effect of venting range hood flow rate on size-resolved UFP concentrations from gas stove cooking. The same cooking protocol was conducted 60 times using three venting range hoods operated at six flow rates in twin research houses. Size-resolved particle (10–420 nm) concentrations were monitored using a NanoScan scanning mobility particle sizer (SMPS) from 15 min before cooking to 3 h after the cooking had stopped. Cooking increased the background total UFP number concentrations to 1.3 × 103 particles/cm3 on average, with a mean exposure-relevant source strength of 1.8 × 1012 particles/min. Total particle peak reductions ranged from 25% at the lowest fan flow rate of 36 L/s to 98% at the highest rate of 146 L/s. During the operation of a venting range hood, particle removal by deposition was less significant compared to the increasing air exchange rate driven by exhaust ventilation. Exposure to total particles due to cooking varied from 0.9 to 5.8 × 104 particles/cm3·h, 3 h after cooking ended. Compared to the 36 L/s range hood, higher flow rates of 120 and 146 L/s reduced the first-hour post-cooking exposure by 76% and 85%, respectively. © 2018 Crown Copyright. Published with license by Taylor & Francis Group, LLC
title: Positive Modulatory Interactions of NMDA Receptor GluN1/2B Ligand Binding Domains Attenuate Antagonists Activity
Creators: name: Bledsoe, Douglas
name: Tamer, Ceyhun
name: Mesic, Ivana
name: Madry, Christian
name: Klein, Bradley G.
name: Laube, Bodo
name: Costa, Blaise M.
Publisher: name: Frontiers Media S.A.
Year: 2024

description: N-methyl D-aspartate receptors (NMDAR) play crucial role in normal brain function and pathogenesis of neurodegenerative and psychiatric disorders. Functional tetra-heteromeric NMDAR contains two obligatory GluN1 subunits and two identical or different non-GluN1 subunits that include six different gene products; four GluN2 (A–D) and two GluN3 (A–B) subunits. The heterogeneity of subunit combination facilities the distinct function of NMDARs. All GluN subunits contain an extracellular N-terminal Domain (NTD) and ligand binding domain (LBD), transmembrane domain (TMD) and an intracellular C-terminal domain (CTD). Interaction between the GluN1 and co-assembling GluN2/3 subunits through the LBD has been proven crucial for defining receptor deactivation mechanisms that are unique for each combination of NMDAR. Modulating the LBD interactions has great therapeutic potential. In the present work, by amino acid point mutations and electrophysiology techniques, we have studied the role of LBD interactions in determining the effect of well-characterized pharmacological agents including agonists, competitive antagonists, and allosteric modulators. The results reveal that agonists (glycine and glutamate) potency was altered based on mutant amino acid sidechain chemistry and/or mutation site. Most antagonists inhibited mutant receptors with higher potency; interestingly, clinically used NMDAR channel blocker memantine was about three-fold more potent on mutated receptors (N521A, N521D, and K531A) than wild type receptors. These results provide novel insights on the clinical pharmacology of memantine, which is used for the treatment of mild to moderate Alzheimer's disease. In addition, these findings demonstrate the central role of LBD interactions that can be exploited to develop novel NMDAR based therapeutics.
The synthesis and analysis of polymers and small molecules for use in organic electronics
Creators: name: Cryer, Samuel Javis
Publisher: name: Imperial College London
Year: 2017

description: Organic Semiconducting materials (OSCs) are integral to the next generation of devices such as flexible screens and solar panels, thanks to their flexible, solution processable and synthetically cheap nature. Although the field of OSCs has moved forward rapidly in the last decade, further research must be conducted to improve performance and efficiencies so as to be competitive with current silicon technologies whilst opening up new markets. One method of improving the current technology is through the chemical modification of these materials to tune their parameters whether this is optical, energetic or morphological. In this thesis, we report the complex synthesis of new thiazole based polymers for use in organic field effect transistors (OFETs) and organic photovoltaics (OPV) with exceptional planarity through a ‘conformational lock’ between the thiazole and thiophene units. Although these polymers performed poorly in OPV and OFET, their interesting properties give new insight into thiazole based polymers, whilst also showing a novel ring closure reaction previously unpublished. This thesis also reports on the synthesis of new diketopyrrolopyrrole polymers with electron rich flanking units used to form strong push-pull hybridisation across the backbone to create low band gap, near-IR absorbing materials. The high molecular weight pDTP-DPP-TT behaveds in a rod like manner due to a ‘hydrogen-bond’ bond-like’ interaction between the DPP core and the DTP flanking unit. This results in exceptionally high extinction coefficients – a prerequisite for high currents in OPV devices. Finally, the thesis reports on the extension of the XBR family with the addition of two new non-fullerene acceptor materials CBR and CBI. The use of non-fullerene acceptors in OPV should not only heavily bring down the materials cost of devices, but also open up new absorption pathways to allow greater device efficiencies. This work looked into how chemical modifications of the central core and flanking units can be used to tune the electronic energy levels, as well as the optoelectronic properties of the materials both individually and in devices.
Composite materials for wind energy applications
Creators: name: Kaboglu, Cihan
Publisher: name: Imperial College London
Year: 2017

description: Weight and strength of materials are important in design for wind energy and aerospace industries. It is a major advance to design new materials for these kinds of applications to achieve high efficiency reducing weight. Sandwich composites and Fibre Metal Laminates (FMLs) are outstanding materials owing to superior mechanical properties. However, they need to be evaluated under static and dynamic loading to which these kinds of applications are subjected. The purpose of the thesis is the investigation of sandwich composite and FMLs for wind turbine blade and aerospace structure evaluating Digital Image Correlation (DIC) and modelling of sandwich composites and FMLs to provide an insight into the failure processes in these materials. In this thesis, sandwich composites with four different core materials and five different surface finishing options were studied. There are advantages in having a softer core near the outer surface to improve impact and mechanical performance and grooves in the core are used to improve resin infusion and draping for curved structures. For the sandwich composites investigated, PVC and PET foam cored sandwich composites can be a substitute foam core material especially for wind turbine blades instead of using balsa cored sandwich composite. In addition, saw-cut (foam is partially cut) and flexi-cut (with grooves on both sides) are surface finishing options often employed to improve the energy absorption and increase the flexural behaviour in a beneficial way. The behaviour of curved sandwich composites was also assessed. In addition, FMLs with three different metal and three different design configurations have been evaluated. The most important parameter for the FMLs are the thickness when considering flexural and impact response of the FMLs. Both of these studies can be guidelines for designing materials for wind turbine blade and aerospace applications to decrease structure weight and increase the mechanical strength of the structure.
Cell and nuclear packing during tissue growth
Creators: name: Schienstock, Dominik
Publisher: name: Imperial College London
Year: 2017

description: Highly proliferative tissues require an optimal cellular organisation to use the available space most effectively. One such organisation is pseudostratification, where cells are tightly packed within a monolayer and their nuclei stack on top of each other. This cellular packing enables, for example, the production of numerous neurons in the brain. Although high proliferation is desired, growth needs to terminate eventually. The mechanisms of growth termination are however complex and largely unknown. The distal part of the Drosophila wing imaginal disc, which gives rise to the adult wing blade, is a model for growth of pseudostratified epithelia. In this tissue, mechanical compression of the apical domain was proposed to cause growth termination. Crucially, nuclei have to undergo apical migration for mitosis. Thus, the packing of nuclei might mechanically influence growth as well. My aim was therefore to quantify nuclei packing (density, volume and position) on a tissue wide scale at different growth stages. An imaging pipeline and a complementary user-guided segmentation program were developed to quantify nuclear packing. The thick and highly folded shape of the wing imaginal disc was preserved and imaged using agarose embedding and a tissue clearing solution, respectively. The nuclear envelope served as a marker to extract 2D shapes which were merged as 3D objects and manually corrected. Local averaging of tiled segmented images was used to compare nuclear parameters of mid and late developmental stages. The analysis indicated that nuclei moved closer together and packed more volume in the available space. My hypothesis is that this close packing of nuclei could contribute to growth termination. While the developed imaging and segmentation pipeline was optimised to extract nuclear parameters, it could also be utilised for other tightly packed tissues, such as tumour spheroids, to extract cells in 3D.
Long-term reconstruction of deep-water oxygen conditions in Osoyoos Lake (British Columbia, Canada): implications for Okanagan River sockeye salmon
Creators: name: Simmatis, Brigitte
name: Jeziorski, Adam
name: Zemanek, Andrea
name: Selbie, Daniel T.
name: Hyatt, Kim
name: Fryer, Jeffrey K.
name: Cumming, Brian F.
name: Smol, John P.
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: FOS: Biological sciences
subject: 69999 Biological Sciences not elsewhere classified
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: Simmatis B, Jeziorski A, Zemanek A, Selbie DT, Hyatt K, Fryer JK, Cumming BF, Smol JP. 2018. Long-term reconstruction of deep-water oxygen conditions in Osoyoos Lake: implications for Okanagan River sockeye salmon. Lake Reserve Manage. 34:392–400. Osoyoos Lake is the primary nursery lake supporting sockeye salmon (Onchorhynchus nerka) originating from the Okanagan River system in south-central British Columbia, Canada. By the early 1960s, Osoyoos Lake had experienced significant cultural eutrophication related to rapid human development of the watershed, increasing total phosphorus concentrations, and frequent algal blooms. Concern exists regarding recent (post-1990s) declines in hypolimnetic oxygen concentrations and the potential degradation of salmon habitat in this multi-basin lake. However, reliable observations are largely unavailable for oxygen conditions prior to the mid-1990s. We reconstructed late-summer volume-weighted hypolimnetic oxygen (VWHO) concentrations in Osoyoos Lake from the late 1800s to 2009 by examining past chironomid (Diptera: Chironomidae) subfossil assemblages from 210Pb-dated lake sediment cores. Chironomid-inferred VWHO revealed only slight variations since the late 1800s (mean values for the north and south basins are 4.4 and 2.9 mg/L, respectively), with seemingly little response to the cultural eutrophication of the mid-20th century. The chironomid-inferred VWHO trends suggest that the current management target of 5.8 mg/L dissolved oxygen for both basins of Osoyoos Lake may require revision to better reflect reference conditions and natural seasonal anoxia.
The converging inflow spectrum is an intrinsic signature for a black hole: Monte-Carlo simulations of Comptonization on free-falling electrons
Creators: name: Laurent, P.
name: Titarchuk, L.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: An accreting black hole is, by definition, characterized by the drain. Namely, the matter falls into a black hole much the same way as water disappears down a drain - matter goes in and nothing comes out. As this can only happen in a black hole, it provides an unique way to see it. The accretion proceeds almost in free fall close to the black hole horizon. In this paper we calculate (by using Monte -Carlo simulations) the specific features of X-ray spectra formed as a result of upscattering of the soft (disk) photons in the converging inflow (CI) within about 3 Schwarzschild radii of the black hole. The full relativistic treatment has been implemented to reproduce these spectra. We show that spectra in the soft state of black hole systems can be described as the sum of a thermal (disk) component and the convolution of some fraction of this component with the CI upscattering spread function. The latter boosted photon component is seen as an extended power-law at energies much higher than the characteristic soft photons energy. We demonstrate the stability of the power spectral index (alpha= 1.8) over a wide range of the plasma temperature 0-10 keV and mass accretion rates (higher than 2 in Eddington units). We also demonstrate that the sharp high energy cutoff occurs at energies of 200-400 keV which are related to the average rest energy of electrons impinging upon the horizon. The spectrum is practically identical to the standard thermal Comptonization spectrum when the CI plasma temperature is getting of order of 50 keV (hard state of BHS). Also, the change of spectral shapes from the soft to the hard X-ray state is clearly to be related with the temperature of the bulk flow. These Monte-Carlo simulated CI spectra are then a inevitable stamp of the BHS.
description: 30 pages TeX format, 6 PS figures, accepted for ApJ Main Journal
Kinematic detection of the double nucleus in M31
Creators: name: Gerssen, J.
name: Kuijken, K.
name: Merrifield, M. R.
Publisher: name: arXiv
Year: 1995
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Using a spectrum obtained under moderate (of order 1 arcsecond) seeing, we show that the double nucleus in M31 produces a strong kinematic signature even though the individual components are not spatially resolved. The signature consists of a significant asymmetric wing in the stellar velocity distribution close to the center of the system. The properties of the second nucleus derived from this analysis agree closely with those measured from high-spatial resolution Hubble Space Telescope images. Even Space Telescope only has sufficient resolution to study the structure of very nearby galactic nuclei photometrically; this spectroscopic approach offers a tool for detecting structure such as multiple nuclei in a wider sample of galaxy cores.
description: 4 pages of uuencoded compressed postscript, figures included. Accepted for publication in MNRAS
The nonlinear redshift-space power spectrum of galaxies
Creators: name: Heavens, A. F.
name: Matarrese, S.
name: Verde, L.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study the power spectrum of galaxies in redshift space, with third order perturbation theory to include corrections that are absent in linear theory. We assume a local bias for the galaxies: i.e. the galaxy density is sampled from some local function of the underlying mass distribution. We find that the effect of the nonlinear bias in real space is to introduce two new features: first, there is a contribution to the power which is constant with wavenumber, whose nature we reveal as essentially a shot-noise term. In principle this contribution can mask the primordial power spectrum, and could limit the accuracy with which the latter might be measured on very large scales. Secondly, the effect of second- and third-order bias is to modify the effective bias (defined as the square root of the ratio of galaxy power spectrum to matter power spectrum). The effective bias is almost scale-independent over a wide range of scales. These general conclusions also hold in redshift space. In addition, we have investigated the distortion of the power spectrum by peculiar velocities, which may be used to constrain the density of the Universe. We look at the quadrupole-to-monopole ratio, and find that higher-order terms can mimic linear theory bias, but the bias implied is neither the linear bias, nor the effective bias referred to above. We test the theory with biased N-body simulations, and find excellent agreement in both real and redshift space, providing the local biasing is applied on a scale whose fractional r.m.s. density fluctuations are $< 0.5$.
description: 13 pages, 7 figures. Accepted by MNRAS
Synthesis of PAMAM dendrimer and its derivative PAMOL: Determination of thermophysical properties by DFT
Creators: name: Indumoni Das
name: Borah, Jyoti Hirok
name: Diganta Sarma
name: Swapnali Hazarika
Publisher: name: Taylor & Francis
Year: 2018
Subjects: subject: Biochemistry
subject: 29999 Physical Sciences not elsewhere classified
subject: FOS: Physical sciences
subject: Medicine
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Sociology
subject: FOS: Sociology
subject: Inorganic Chemistry

description: Dendrimer (G-0.5 and G0 PAMAM) and derivative of G-0.5 PAMAM (Hydroxy substituted PAMAM, hereafter called PAMOL) were synthesized using different catalyst such as KF/Al2O3, 15-Crown-ether, Aliqate-336, 15-Crown-ether & Aliqate-336, K2CO3, and Lipase. Products were characterized by IR, NMR and GCMS analysis. The yield of the product was calculated for each reaction and it was found that lipase from Candida antarctica acts as the best catalyst for the reactions with maximum yield 95% and 78% for PAMAM and PAMOL respectively. The structure of PAMAM and PAMOL were optimized by Density Functional Theory at B3LYP/6-311++ G (d,p) and CAM-B3LYP/6-311++G(d,p) level of theory using Gaussian 09 to check the consistency of the results. The thermodynamic properties of the compounds such as thermal energy, enthalpy and Gibbs free energy were determined and reported. The global reactivity descriptors such as chemical potential (μ), hardness (η) and electrophilicity index (ω) were also calculated to characterize the reactive stability of the molecules.
Metal Abundances at z < 1.5: Fresh Clues to the Chemical Enrichment History of Damped Lyman alpha Systems
Creators: name: Pettini, Max
name: Ellison, Sara L.
name: Steidel, Charles C.
name: Bowen, David V.
Publisher: name: arXiv
Year: 1998
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We explore the redshift evolution of the metal content of damped Lyman alpha systems (DLAs) with new observations of four absorbers at z < 1.5 . The main conclusion is that the column density--weighted mean metallicity, [] = -1.03 +/- 0.23 (on a logarithmic scale), is not significantly higher at z < 1.5 than at earlier epochs, despite the fact that the comoving star formation rate density of the universe was near its maximum value at this redshift. For three of the four DLAs our observations include absorption lines of Si, Mn, Cr, Fe, and Ni, as well as Zn. We argue that the relative abundances of these elements are consistent with a moderate degree of dust depletion which, once accounted for, leaves no room for the enhancement of the alpha-elements over iron seen in metal poor stars in the Milky Way. This is contrary to previous assertions that DLAs have been enriched solely by Type II supernovae, but can be understood if the rate of star formation in the systems studied proceeded more slowly than in the early history of our Galaxy. These results add to a growing body of data all pointing to the conclusion that known DLAs do not trace the galaxy population responsible for the bulk of star formation. Possible reasons are that sight-lines through metal rich gas are systematically underrepresented because the background QSOs are reddened, and that the most actively star forming galaxies are also the most compact, presenting too small a cross-section to have been probed yet with the limited statistics of current samples.
description: 40 pages, LaTex, 9 Postscript Figures. Accepted for publication in the Astrophysical Journal