FTIR autecological analysis of bottom-ice diatom taxa across a tidal strait in the Canadian Arctic

A recent study demonstrated that an Arctic tidal strait, where a shoaled and constricted waterway increases tidally driven sub-ice currents and turbulence, represents a “hotspot” for ice algal production due to a hypothesized enhanced ocean-ice nutrient supply. Based on these findings, we sampled the bottom-ice algal community across the same tidal strait between the Finlayson Islands within Dease Strait, Nunavut, Canada, in spring 2017. Our objective was to examine cellular responses of sea-ice diatoms to two expected nutrient supply gradients in their natural environment: (1) a horizontal gradient across the tidal strait and (2) a vertical gradient in the bottom-ice matrix. Two diatom taxa, Nitzschia frigida and Attheya spp. in bottomice sections (0–2, 2–5, and 5–10 cm) under thin snow cover (<5 cm), were selected for Fourier Transform Infrared (FTIR) spectrochemical analysis for lipid and protein content. Results from the FTIR technique strongly supported the existence of a horizontal nutrient gradient across the tidal strait of the Finlayson Islands, while estimates of particulate organic carbon and chlorophyll a concentrations were difficult to interpret. The larger N. frigida cells appeared to be more sensitive to the suspected horizontal nutrient gradient, significantly increasing in lipid content relative to protein beyond the tidal strait. In contrast, the epiphytic diatoms, Attheya spp., were more sensitive to the vertical gradient: above 2 cm in the bottom-ice matrix, the non-motile cells appeared to be trapped with a depleted nutrient inventory and evidence of a post-bloom state. Application of the FTIR technique to estimate biomolecular composition of algal cells provided new insights on the response of the bottom-ice algal community to the examined spatial gradients that could not be obtained from conventional bulk measurements alone. Future studies of sea ice and associated environments are thus encouraged to employ this technique

Inkjet-Printed Carbon Nanotubes for Fabricating a Spoof Fingerprint on Paper.

A spoof fingerprint was fabricated on paper and applied for a spoofing attack to unlock a smartphone on which a capacitive array of sensors had been embedded with a fingerprint recognition algorithm. Using an inkjet printer with an ink made of carbon nanotubes (CNTs), we printed a spoof fingerprint having an electrical and geometric pattern of ridges and furrows comparable to that of the real fingerprint. With this printed spoof fingerprint, we were able to unlock a smartphone successfully; this was due to the good quality of the printed CNT material, which provided electrical conductivities and structural patterns similar to those of the real fingerprint. This result confirms that inkjet-printing CNTs to fabricate a spoof fingerprint on paper is an easy, simple spoofing route from the real fingerprint and suggests a new method for outputting the physical ridges and furrows on a two-dimensional plane

Affordable Fabrication of Conductive Electrodes and Dielectric Films for a Paper-based Digital Microfluidic Chip

In order to fabricate a digital microfluidic (DMF) chip, which requires a patterned array of electrodes coated with a dielectric film, we explored two simple methods: Ballpoint pen printing to generate the electrodes, and wrapping of a dielectric plastic film to coat the electrodes. For precise and programmable printing of the patterned electrodes, we used a digital plotter with a ballpoint pen filled with a silver nanoparticle (AgNP) ink. Instead of using conventional material deposition methods, such as chemical vapor deposition, printing, and spin coating, for fabricating the thin dielectric layer, we used a simple method in which we prepared a thin dielectric layer using pre-made linear, low-density polyethylene (LLDPE) plastic (17-μm thick) by simple wrapping. We then sealed it tightly with thin silicone oil layers so that it could be used as a DMF chip. Such a treated dielectric layer showed good electrowetting performance for a sessile drop without contact angle hysteresis under an applied voltage of less than 170 V. By using this straightforward fabrication method, we quickly and affordably fabricated a paper-based DMF chip and demonstrated the digital electrofluidic actuation and manipulation of drops

Vertical distributions of organic matter components in sea ice near Cambridge Bay, Dease Strait, Canadian Archipelago

Ice algae thriving within sea ice play a crucial role in transferring energy to higher trophic levels and influencing biogeochemical processes in polar oceans; however, the distribution of organic matter within the ice interior is not well understood. This study aimed to investigate the vertical distribution of organic matter, including chlorophyll a (Chl-a), particulate organic carbon and nitrogen (POC and PON), carbohydrates (CHO), proteins (PRT), lipids (LIP), and food material (FM), within the sea ice. Samples were collected from the bottom, middle, and top sections of the sea ice column near Cambridge Bay during the spring of 2018. Based on the δ13C signature, biochemical composition, and POC contribution of biopolymeric carbon (BPC), the organic substances within the sea ice were predominantly attributed to marine autotrophs. While the highest concentrations of each parameter were observed at the sea ice bottom, notable concentrations were also found in the upper sections. The average sea ice column-integrated Chl-a concentration was 5.05 ± 2.26 mg m−2, with the bottom ice section contributing 59% (S.D. = ± 10%) to the total integration. The column-integrated concentrations of FM, BPC, POC, and PON were 2.05 ± 0.39, 1.10 ± 0.20, 1.47 ± 0.25, and 0.09 ± 0.03 g m−2, respectively. Contributions of the bottom ice section to these column-integrated concentrations varied for each parameter, with values of 20 ± 6, 21 ± 7, 19 ± 5, and 28 ± 7%, respectively. While the bottom ice section exhibited a substantial Chl-a contribution in line with previous studies, significantly higher contributions of the other parameters were observed in the upper sea ice sections. This suggests that the particulate matter within the interior of the sea ice could potentially serve as an additional food source for higher trophic grazers or act as a seeding material for a phytoplankton bloom during the ice melting season. Our findings highlight the importance of comprehensive field measurements encompassing the entire sea ice section to better understand the distribution of organic carbon pools within the sea ice in the Arctic Ocean

PLK1 phosphorylation of pericentrin initiates centrosome maturation at the onset of mitosis

PLK1-mediated phosphorylation of pericentrin induces proper organization of the spindle pole–specific pericentriolar matrix and subsequent centrosome maturation

Pushing the Boundaries of Hydroacylation: Development of Rhodium- and Cobalt-Catalyzed Reactions

Cross-couplings that proceed via C–H bond activation streamline the synthesis of complex molecules. Rhodium complexes are promising catalysts for these reactions and they readily activate aldehyde C–H bonds to generate acyl-Rh-hydrides. Developing strategies to control the reactivity of these oxidative addition products enables developments in hydroacylation.Chapter 1 describes the development of a cobalt-catalyst that can couple aldehydes and dienes selectively to make new ketone products. Our Co-catalyzed hydroacylation circumvents migratory deinsertion pathways by avoiding formation of an acyl-metal-hydride intermediate. This work spurred renewed interest in base metal-catalysis in the development of new hydroacylation reactions. Chapter 2 describes the synthesis of dienyl aldehydes that can be cycloisomerized into a variety of scaffolds by careful choice of the Rh-catalyst system employed. One substrate can be derivatized into cyclopentanones, cyclohexenals, [2.2.1]-bicycloheptanones, and bis(acyl)octanone scaffolds. The details regarding asymmetric cyclopentanones containing an all-carbon quaternary center will be described. Included will be our mechanistic understanding of the reaction and its ability to reach the other scaffolds. Chapter 3 describes the complementary use of Co-catalysis to cyclize dienyl aldehydes into strained cyclobutanones. This takes advantage of unique properties of cobalt- versus rhodium-catalysis. Furthermore, the evaluation of the catalyst system using a robustness evaluation as well as further mechanistic probes will be described

Pushing the Boundaries of Hydroacylation: Development of Rhodium- and Cobalt-Catalyzed Reactions

Cross-couplings that proceed via C–H bond activation streamline the synthesis of complex molecules. Rhodium complexes are promising catalysts for these reactions and they readily activate aldehyde C–H bonds to generate acyl-Rh-hydrides. Developing strategies to control the reactivity of these oxidative addition products enables developments in hydroacylation.Chapter 1 describes the development of a cobalt-catalyst that can couple aldehydes and dienes selectively to make new ketone products. Our Co-catalyzed hydroacylation circumvents migratory deinsertion pathways by avoiding formation of an acyl-metal-hydride intermediate. This work spurred renewed interest in base metal-catalysis in the development of new hydroacylation reactions. Chapter 2 describes the synthesis of dienyl aldehydes that can be cycloisomerized into a variety of scaffolds by careful choice of the Rh-catalyst system employed. One substrate can be derivatized into cyclopentanones, cyclohexenals, [2.2.1]-bicycloheptanones, and bis(acyl)octanone scaffolds. The details regarding asymmetric cyclopentanones containing an all-carbon quaternary center will be described. Included will be our mechanistic understanding of the reaction and its ability to reach the other scaffolds. Chapter 3 describes the complementary use of Co-catalysis to cyclize dienyl aldehydes into strained cyclobutanones. This takes advantage of unique properties of cobalt- versus rhodium-catalysis. Furthermore, the evaluation of the catalyst system using a robustness evaluation as well as further mechanistic probes will be described

A study on the efficient numerical analysis for the prediction of full-scale propeller performance using CFD

In Computational Fluid Dynamics (CFD) simulations, limited number of full-scale studies with ship propellers have been conducted due to the limitation of computational resources and computation time. There are two methods for efficient full-scale numerical analysis; (1) a method of using large non-dimensional wall-normal distances (y +) and (2) a method of applying a virtual fluid at a model scale. However, there are lack of study on the validity of using large y+ in full-scale propeller simulations and applying virtual fluids. Thus, the aim of this study is to investigate the effect of different wall y+ values in a real fluid and the virtual fluid concept to predict full-scale propeller performance using CFD. For these investigations, the commercial CFD tool, STAR-CCM+, was used to predict the propeller open water (POW) performance of the KRISO benchmark propeller (KP505) in model and full-scale. The results presented include the pressures, friction, streamlines, and tip vortex formation characteristics. The findings of this research study support the use of a small value of wall y+ (i.e., y+<1) for the model scale simulations, but the effect of the wall y+ is negligible in full-scale. This study also demonstrates that the similarity requirements for the advance coefficient and Reynolds number could be satisfied simultaneously in full-scale by using the virtual fluid properties without any need to conduct more computationally demanding full-scale simulations with real fluid.In Computational Fluid Dynamics (CFD) simulations, limited number of full-scale studies with ship propellers have been conducted due to the limitation of computational resources and computation time. There are two methods for efficient full-scale numerical analysis; (1) a method of using large non-dimensional wall-normal distances (y +) and (2) a method of applying a virtual fluid at a model scale. However, there are lack of study on the validity of using large y+ in full-scale propeller simulations and applying virtual fluids. Thus, the aim of this study is to investigate the effect of different wall y+ values in a real fluid and the virtual fluid concept to predict full-scale propeller performance using CFD. For these investigations, the commercial CFD tool, STAR-CCM+, was used to predict the propeller open water (POW) performance of the KRISO benchmark propeller (KP505) in model and full-scale. The results presented include the pressures, friction, streamlines, and tip vortex formation characteristics. The findings of this research study support the use of a small value of wall y+ (i.e., y+<1) for the model scale simulations, but the effect of the wall y+ is negligible in full-scale. This study also demonstrates that the similarity requirements for the advance coefficient and Reynolds number could be satisfied simultaneously in full-scale by using the virtual fluid properties without any need to conduct more computationally demanding full-scale simulations with real fluid

CEP90 is required for the assembly and centrosomal accumulation of centriolar satellites, which is essential for primary cilia formation.

Centriolar satellites are PCM-1-positive granules surrounding centrosomes. Proposed functions of the centriolar satellites include protein targeting to the centrosome, as well as communication between the centrosome and surrounding cytoplasm. CEP90 is a centriolar satellite protein that is critical for spindle pole integrity in mitotic cells. In this study, we examined the biological functions of CEP90 in interphase cells. CEP90 physically interacts with PCM-1 at centriolar satellites, and this interaction is essential for centrosomal accumulation of the centriolar satellites and eventually for primary cilia formation. CEP90 is also required for BBS4 loading on centriolar satellites and its localization in primary cilia. Our results imply that the assembly and transport of centriolar satellites are critical steps for primary cilia formation and ciliary protein recruitment