Latent ice recrystallization inhibition activity in nonantifreeze proteins : Ca2+-activated plant lectins and cation-activated antimicrobial peptides

Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs

Late Cretaceous to Paleocene Tectonometamorphic Evolution of the Blanchard River Assemblage, Southwest Yukon: New Insight into the Terminal Accretion of Insular Terranes in the Northern Cordillera

The Intermontane-Insular terrane boundary stretches over 2000 kilometers from British Columbia to Alaska in the western Cordillera. Juxtaposed between these terranes is a series of Jura-Cretaceous basinal and arc assemblages that record a complicated and contested tectonic evolution related to the Mesozoic-Paleocene accretionary history of northwestern North America. In southwest Yukon, west-verging thrust faults facilitated structural stacking of the Yukon-Tanana terrane over these basinal assemblages, including the Early Cretaceous Blanchard River assemblage. These previously undated compressional structures are thought to be related to the final collapse of the Jura-Cretaceous basins and the tectonic burial of the Blanchard River assemblage resulting in amphibolite facies metamorphism. New in situ U-Th-Pb monazite ages record at least three tectonic events: (1) the tectonic burial of the Blanchard River assemblage to amphibolite facies conditions between 83 and 76 Ma; (2) peak burial was followed by regional exhumation at ca. 70-68 Ma; and (3) intense heating and ca. 63-61 Ma low-pressure contact metamorphism attributed to the intrusion of the voluminous Ruby Range suite, which is part of the northern Coast Mountains batholith. The tectonometamorphic evolution recorded in the Blanchard River assemblage can be correlated to tectonism within southwest Yukon and along the length of the Insular-Intermontane boundary from western British Columbia through southwestern Yukon and Alaska. In southwest Yukon, these results suggest an asymmetric final collapse of Jura-Cretaceous basins during the Late Cretaceous, which relates to the terminal accretion of the Insular terranes as they moved northward

Investigating the Effect of Carbon Nanotube Diameter and Wall Number in Carbon Nanotube/Silicon Heterojunction Solar Cells

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).Suspensions of single-walled, double-walled and multi-walled carbon nanotubes (CNTs) were generated in the same solvent at similar concentrations. Films were fabricated from these suspensions and used in carbon nanotube/silicon heterojunction solar cells and their properties were compared with reference to the number of walls in the nanotube samples. It was found that single-walled nanotubes generally produced more favorable results; however, the double and multi-walled nanotube films used in this study yielded cells with higher open circuit voltages. It was also determined that post fabrication treatments applied to the nanotube films have a lesser effect on multi-walled nanotubes than on the other two types

Facile one-pot synthesis of amoxicillin-coated gold nanoparticles and their antimicrobial activity

Nanomaterials have been the object of intense study due to promising applications in a number of different disciplines. In particular, medicine and biology have seen the potential of these novel materials with their nanoscale properties for use in diverse areas such as imaging, sensing and drug vectorisation. Gold nanoparticles (GNPs) are considered a very useful platform to create a valid and efficient drug delivery/carrier system due to their facile and well-studied synthesis, easy surface functionalization and biocompatibility. In the present study, stable antibiotic conjugated GNPs were synthesised by a one-step reaction using a poorly water soluble antibiotic, amoxicillin. Amoxicillin, a member of the penicillin family, reduces the chloroauric acid to form nanoparticles and at the same time coats them to afford the functionalised nanomaterial. A range of techniques including UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were used to ascertain the gold/drug molar ratio and the optimum temperature for synthesis of uniform monodisperse particles in the ca. 30-40 nm size range. Amoxicillin-conjugated gold showed an enhancement of antibacterial activity against Escherichia coli compared to the antibiotic alone

From Paris to Projects: Clarifying the Implications of Canada’s Climate Change Mitigation Commitments for the Planning and Assessment of Projects and Strategic Undertakings (Full Report)

Canada has signed the Paris Agreement and made other international commitments to doing our fair share of what is needed to keep overall global warming to the Paris Agreement limit of well below 2ºC, and to aim for 1.5ºC, to avoid devastating climate change. However, we have not yet progressed far in translating these commitments into implications for decision making on proposed undertakings with significant implications for meeting those commitments.Clarifying those implications and determining how best to incorporate them in deliberations and decision making is overdue and now imperative. The federal government’s new Impact Assessment Act, which is now proceeding through Parliament’s legislative process, stands to require that all assessments decisions be based in part on evaluation of the extent to which the effects of the designated project hinder or contribute to the Government of Canada’s ability to meet its environmental obligations and its commitments in respect of climate change. (Impact Assessment Act, section 63(e)).In this report, we present the findings of an initial effort to delineate and address the gap between Paris and projects. We set out the needed steps and their main implications, especially for new assessment law, regulation and policy. The steps are not fully defined and many components include a range of possible options. Our intent and expectations have not been to deliver final answers but to establish a firm basis for informed conversation of a matter of pressing importance. The challenges identified in this report are numerous and demanding but reasonably clear.Our main findings and recommendations are summarized in part 5, the concluding section of the report

From Paris to Projects Clarifying the Implications of Canada’s Climate Change Mitigation Commitments for the Planning and Assessment of Projects and Strategic Undertakings (Summary Report)

By signing the Paris Agreement, Canada made a commitment to do our fair share to limit global average temperature rise to “well below 2°C” relative to pre-industrial levels, and to pursue “efforts to limit the increase to 1.5°C.” The federal Impact Assessment Act that is now before Parliament requires consideration of whether assessed undertakings would “hinder or contribute to” meeting Canada’s climate change commitments.So far, however, Canada has done little to define what the Paris Agreement entails for planning, assessment and decision making on projects and other undertakings with significant implications for meeting the Paris commitments. That leaves a serious gap in law, policy and practice between Canada’s commitments and the assessment of major undertakings.Assessments are an important venue for proactive climate change mitigation. They guide decision making on major extractive and infrastructure projects and other undertakings that will entrench existing practices or drive key transitions for many decades. If these assessments are to contribute to meeting our climate change mitigation commitments, we need to understand what meeting those commitments entails – how far we have to go and what we have to do to close the gap between our current efforts and our promised accomplishments.To inform serious efforts to fill that gap, this paper examines• what the Paris Agreement’s temperature goals imply for global and Canadian GHG reduction targets in light of “fair share” principles and feasible pathways;• what is needed to raise Canadian climate change mitigation ambitions to the Paris Agreement level, and ensure sufficiently strengthened and clarified targets, frameworks and applied tools to inform evaluations of particular undertakings; and• how to translate these needs and tools into well-specified and authoritative requirements for effective application under federal assessment law.Our intent has not been to deliver final answers but to establish a reasonably firm working base for comparing what we are doing with what is needed to meet our Paris commitments

The Northern Termination of the Cache Creek Terrane in Yukon: Middle Triassic Arc Activity and Jurassic–Cretaceous Structural Imbrication

The northernmost part of the Cache Creek terrane lies in south-central Yukon and comprises metavolcanic rocks, hemipelagic chert and shale, newly identified volcaniclastic and clastic rocks (Michie formation, informal), pyroxenite and gabbro intrusive rocks with an arc to back-arc geochemical signature, as well as tectonized and serpentinized ultramafic rocks. The proximally sourced Michie formation yielded zircon from two samples with unimodal peaks at 245.85 ± 0.07 and 244.64 ± 0.08 Ma. These dates are likely close to the depositional ages and compare favourably with those from the Kutcho assemblage of northern British Columbia. The Michie formation is exposed along the northwestern flank of Mount Michie and represents singular detrital input from a nearby eroding island-arc. The Cache Creek terrane rocks are imbricated with epiclastic and carbonate rocks of the Stikinia and Lower Jurassic siliciclastic rocks of the synorogenic Whitehorse trough. This imbrication records two compressional deformation phases in the region: (1) an initial phase of west-verging thrusting along the Judas Mountain fault that placed the Cache Creek terrane rocks over the arc and basinal rocks of Stikinia and Whitehorse trough; and (2) a second phase of east-verging thrusting along the Mount Michie fault that repositioned rocks of Stikinia and the Whitehorse trough structurally above those of the Cache Creek terrane. Deformation in the centre of the study area was followed by emplacement of a coarse-grained syenite that yielded 40Ar/39Ar biotite and muscovite cooling ages of 165–160 Ma

Mobile phone-delivered reminders and incentives to improve childhood immunisation coverage and timeliness in Kenya (M-SIMU): a cluster randomised controlled trial

Background As mobile phone access continues to expand globally, opportunities exist to leverage these technologies to support demand for immunisation services and improve vaccine coverage. We aimed to assess whether short message service (SMS) reminders and monetary incentives can improve immunisation uptake in Kenya. Methods In this cluster-randomised controlled trial, villages were randomly and evenly allocated to four groups: control, SMS only, SMS plus a 75 Kenya Shilling (KES) incentive, and SMS plus 200 KES (85 KES = USD$1). Caregivers were eligible if they had a child younger than 5 weeks who had not yet received a first dose of pentavalent vaccine. Participants in the intervention groups received SMS reminders before scheduled pentavalent and measles immunisation visits. Participants in incentive groups, additionally, received money if their child was timely immunised (immunisation within 2 weeks of the due date). Caregivers and interviewers were not masked. The proportion of fully immunised children (receiving BCG, three doses of polio vaccine, three doses of pentavalent vaccine, and measles vaccine) by 12 months of age constituted the primary outcome and was analysed with logbinomial regression and General Estimating Equations to account for correlation within clusters. This trial is registered with ClinicalTrials.gov, number NCT01878435. Findings Between Oct 14, 2013, and Oct 17, 2014, we enrolled 2018 caregivers and their infants from 152 villages into the following four groups: control (n=489), SMS only (n=476), SMS plus 75 KES (n=562), and SMS plus 200 KES (n=491). Overall, 1375 (86%) of 1600 children who were successfully followed up achieved the primary outcome, full immunisation by 12 months of age (296 [82%] of 360 control participants, 332 [86%] of 388 SMS only participants, 383 [86%] of 446 SMS plus 75 KES participants, and 364 [90%] of 406 SMS plus 200 KES participants). Children in the SMS plus 200 KES group were significantly more likely to achieve full immunisation at 12 months of age (relative risk 1·09, 95% CI 1·02–1·16, p=0·014) than children in the control group. Interpretation In a setting with high baseline immunisation coverage levels, SMS reminders coupled with incentives significantly improved immunisation coverage and timeliness. Given that global immunisation coverage levels have stagnated around 85%, the use of incentives might be one option to reach the remaining 15%

An optical fiber double scrambler and mechanical agitator system for the Keck planet finder spectrograph

We present the design and test results of a double-scrambler and fiber agitator system for the Keck Planet Finder (KPF) spectrograph. The mechanical agitator for modal noise suppression is constructed from two linear stages with the fibers mounted in a “W” curve. When driven back-and-forth at different rates, the stages change the position of the fiber curves, and hence vary the modes propagating through the fiber. Near-field temporal centroid shifts caused by modal-noise are reduced by a factor of 100 by the agitator, while mid-range spatial frequencies have reduced power by a factor of ∼300 in the near-field, and ∼1000 in the far-field. The scrambling system incorporates two octagonal fibers, and a scrambler consisting of two identical cemented lenses ∼20 cm apart, which exchanges the optical near- and far-fields of the fibers. The scrambler shows scrambling gains >16,000 in the near-field, and >40,000 in the far-field. The measured throughput efficiency of 99.3% of the expected maximum demonstrates that scrambler-induced focal ratio degradation (FRD) is minimal. The scrambler also serves as the feed-through into the vacuum chamber where the spectrograph is housed, thereby removing concerns about stressing the fibers, and introducing FRD, at this interface. Our illumination stabilization system, consisting of two octagonal fibers, a two lens scrambler, and a mechanical agitator, produces very homogeneous fiber output in both the near and far-fields. When coupled to the Keck Planet Finder spectrograph, this system provides illumination stability corresponding to a velocity of 0.30 m s^(−1)

The Sloan Digital Sky Survey Reverberation Mapping Project: Rapid CIV Broad Absorption Line Variability

We report the discovery of rapid variations of a high-velocity CIV broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4sigma) variability in the equivalent width of the broad (~4000 km/s wide) CIV trough on rest-frame timescales as short as 1.20 days (~29 hours), the shortest broad absorption line variability timescale yet reported. The equivalent width varied by ~10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n_e > 3.9 x 10^5 cm^-3. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.Comment: 15 pages, 14 figures. Accepted for publication in the Astrophysical Journa