Stratigraphy, petrology, and depositional environments of the Jarvis creek coalfield, Alaska

Jarvis Creek basin coals are subbituminous, low in ash, and increase upsection in moisture, most major oxides and trace elements, and vitrinite with subsequent liptinite and inertinite decreases. Sulfide mineral deposits east-southeast of the basin are responsible for the enrichment of the upper coals in sulfur and metals. Sandstones are quartzose, arkosic, and lithic in the lower, middle, and upper units respectively, and were derived from a recycled orogen provenance. Sediment transport was from the south at the base, shifting to an easterly source higher in the section. Deposition was by braided and meandering streams on mid and distal portions of alluvial fans. The lower and middle units are correlative with the Healy Creek Formation, while the upper unit probably correlates with the Lignite Creek Formation. Measured, indicated, and inferred coal reserves are 17, 37, and 227 million short tons respectively, mostly in the upper unit at shallow depths.Presented to the Faculty of the University of Alaska in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENC

Human-based fibrillar nanocomposite hydrogels as bioinstructive matrices to tune stem cell behavior

The extracellular matrix (ECM)-biomimetic fibrillar structure of platelet lysate (PL) gels along with its enriched milieu of biomolecules has drawn significant interest in regenerative medicine applications. However, PL-based gels have poor structural stability which severely limits its performance as a bioinstructive biomaterial. Here, rod-shaped cellulose nanocrystals (CNC) are used as a novel approach to modulate the physical and biochemical microenvironment of PL gels enabling their effective use as injectable human-based cell scaffolds with a level of biomimicry that is difficult to recreate with synthetic biomaterials. The incorporation of CNC (0 to 0.61 wt.%) into the PL fibrillar network during the coagulation cascade leads to decreased fiber branching, increased interfiber porosity (from 66 to 83%) and modulate fiber (from 1.4 ± 0.7 to 27 ± 12 kPa) and bulk hydrogel (from 18 ± 4 to 1256 ± 82 Pa) mechanical properties. As result of these physicochemical alterations, nanocomposite PL hydrogels resist to the typical extensive clot retraction (from 76 ± 1 to 24 ± 3 at Day 7) and show favored retention of PL bioactive molecules. The feedback of these cues on the fate of human adipose-derived stem cells is evaluated, showing how it can be explored to modulate the commitment of encapsulated stem cells toward different genetic phenotypes without the need for additional external biological stimuli. These fibrillar nanocomposite hydrogels allow therefore to explore the outstanding biological properties of human-based PL as an efficient engineered ECM which can be tailored to trigger specific regenerative pathways in minimal invasive strategies.The authors thank the Hospital da Prelada (Porto, Portugal) for providing adipose tissue samples. The authors acknowledge the financial support from project Recognize (UTAP-ICDT/CTM-BIO/0023/2014), project NORTE-01-0145FEDER-000021 supported by the Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), the European Union Framework Programme for Research and Innovation HORIZON 2020, under the TEAMING Grant agreement No. 739572 – The Discoveries CTR EU, Forecast 668983, Marie Skłodowska-Curie grant agreement No. 706996 (PrinTendon) and CHEM2NATURE 692333; FCT/MCTES (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia, e Ensino Superior) and the Fundo Social Europeu através do Programa Operacional do Capital Humano (FSE/POCH) in the framework of PhD grant PD/59/2013 – PD/BD/113807/2015 for BBM, Post-Doc grant SFRH/BPD/112459/2015 for R.D.info:eu-repo/semantics/publishedVersio

Metal-organic frameworks with designed chiral recognition sites

Linking struts containing Cram-like bisbinaphthyl[22]crown-6 with Zn4O(CO2)6 joints affords metal–organic frameworks with chiral recognition sites that are highly designed, ordered and placed in a precise manner throughout the entire crystal.Cory Valente, Eunwoo Choi, Matthew E. Belowich, Christian J. Doonan, Qiaowei Li, Travis B. Gasa, Youssry Y. Botros, Omar M. Yaghi and J. Fraser Stoddar

Application of Crystallization-Induced Asymmetric Transformation to a General, Scalable Method for the Resolution of 2,8-Disubstituted Tröger’s Base Derivatives

A general method for the gram scale resolution of 2-substituted and 2,8-disubstituted Tröger’s base (TB) derivatives in 63–91% yield has been achieved through the application of crystallization-induced asymmetric transformation (CIAT). Enantiomeric ratios of the resolved TB derivatives range from 99.1:0.9 to >99.5:0.5. Among the Tröger’s base compounds resolved are four synthetically valuable bromo and iodo derivatives

On-Surface Polymerization: From Polyarylenes to Graphene Nanoribbons and Two-Dimensional Networks

On-surface polymerization is a novel technique for the fabrication of one- and two-dimensional molecular networks confined on a surface and is a rapidly developing field in surface science. The molecular building blocks exhibit pre-defined connection sites at which, after thermal activation and diffusion on the surface, the molecules are linked in a clean environment. Depending on the position and number of these connection sites, activated molecules polymerize to yield chains or two-dimensional networks. The chemical composition of the resulting polymer is precisely defined by the precursor molecules. We review current developments in the field of on-surface polymerization and present different examples, including the fabrication of graphene nanoribbons. We introduce reductive Ullmann-type coupling as well as Scholl-type cyclodehydrogenation for fabrication of graphene nanoribbons of increasing width. The surface plays a crucial role during the activation and polymerization processes because it serves as a catalyst, promotes molecular diffusion, and has a huge influence on the final molecular architecture. One-dimensional polymers can act as molecular wires and their conductance has been studied at the level of individual chains. In addition, we discuss two-dimensional networks and describe recent progress in attempts to improve their quality using sequential activation or defect-healing