Synthesis and Structural Characterizations of Ansa-Vanadabis(tricarbadecaboranyl) Sandwich Complexes

A new linked bis(tricarbadecaboranyl) dianion has been used to form the first examples of ansa-vanadabis(tricarbadecaboranyl) complexes. The Li2+[6,6-(CH2)4-nido-(5,6,9-C3B7H9)2]2– (1) dianion was produced by a carbon-insertion route involving the reaction of two equivalents of arachno-4,6-C2B7H12– with adiponitrile. The reaction of 1 with VCl3·THF produced two isomeric ansa-vanadabis(tricarbadecaboranyl) complexes, ansa-(2′,4-(CH2)4-)-commo-V-(1′-V-2′,3′,5′-C3B7H9)(1-V-2,3,4-C3B7H9) (2) and ansa-(2′,4-(CH2)4-)-commo-V-(1′-V-2′,3′,4′-C3B7H9)(1-V-2,3,4-C3B7H9) (3). Crystallographic determinations showed that in both complexes a formal V2+ ion is sandwiched between two tricarbadecaboranyl cages that are linked by the ansa-(CH2)4– group, but that the points of linker-attachment on the two cages are different. One cage of each complex has the linkage attached to the C2 cage-carbon, but in the other cage, a cage-atom rearrangement moved the C2 cage-carbon along with its attached –(CH2)4– linker to an adjacent 4-position. This rearrangement along with the long flexible –(CH2)4– linker enables the two cages in each complex to rotate into a perpendicular interlocking configuration that maximizes the bonding interaction with the metal, reduces unfavorable steric interactions between the two linked cages and encapsulates the vanadium inhibiting its interactions with other potential ligands. The isomeric structures of 2 and 3 differ as a result of their being formed from different combinations of the enantiomeric forms of the –(CH2)4–C3B7H9 cages, with the C4 and C5′ carbons on opposite sides of the tether in 2, whereas in 3 the C4 and C4′ carbons are on the same side

Functionalized Ruthenatricarbadecaborane via Selective Cage Iodination and Sonogashira Coupling Reactions

Selective iodination of the cyclopentadienylruthenium tricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–closo-1,2,3,4-RuC3B7H9 (1) and 1-(η5-C5(CH3)5)–2-Ph–closo-1,2,3,4-RuC3B7H8 (2) to form their mono-iodo derivatives, 1-(η5-C5H5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H9 (3) and 1-(η5-C5(CH3)5)–2-Ph–6-I–closo-1,2,3,4-RuC3B7H8(4), was achieved in 90% yields by their reactions with ICl in CH2Cl2 solutions. Also isolated in trace amounts from the reaction with 2 was the di-iodo 1-(η5-C5(CH3)5)–2-Ph–6,11-I2–closo-1,2,3,4-RuC3B7H7, (5) complex. The sonication-promoted Sonogashira coupling reaction of 3 with terminal acetylenes catalyzed by Pd(dppf)Cl2/CuI yielded the functionalized ruthenatricarbadecaboranyl complexes 1-(η5-C5H5)–2-Ph–6-(Ph-C≡C)–closo-1,2,3,4-RuC3B7H8 (6), 1-(η5-C5H5)–2-Ph–6-[CH3CH2C(O)OCH2-C≡C]–closo-1,2,3,4-RuC3B7H8 (7), 1-(η5-C5H5)–2-Ph–6-[(η5-C5H5)Fe(η5-C5H4)-C≡C]–closo-1,2,3,4-RuC3B7H8 (8) and 1-(η5-C5H5)–2-Ph–6-[(CH3)3Si-C≡C]–closo-1,2,3,4-RuC3B7H8 (9). These reactions thus provide a versatile, systematic pathway for the syntheses of a wide variety of new types of functionalized ruthenatricarbadecaboranyl complexes

The Role of Dynamic Ligand Exchange in the Oxidation Chemistry of Cerium(III)

The CeIII/IV couple is useful for many applications in organic, inorganic, and materials chemistry. However, attaining a general method to access both oxidations states through reversible solution redox chemistry remains challenging. Herein we report the synthesis, characterization, and oxidation chemistry of the novel Ce/Li REMB heterochiral diastereomer, 1-Ce(het). The solution exchange processes of 1-RE(het) (RE ¼ Ce and Yb) were investigated to estimate rates of ligand and cation exchange relevant in homochiral and heterochiral frameworks. A detailed mechanistic investigation following the solution dynamics of 1-Ce(het) revealed reactivity controlled both by ligand reorganization and redistribution processes. Ligand reorganization was responsible for the kinetics associated with the chemical oxidation reaction, whereas ligand redistribution and exchange dictated the isolated product

Spherical Panoramic Image Payload Design for Stratospheric Ballooning

The 2017 total solar eclipse inspired innovation in design and implementation in stratospheric ballooning techniques and payloads to fully document the unique near-space experience. The Arkansas BalloonSAT team, as part of the Eclipse Ballooning Project, designed and fabricated a spherical panoramic image payload using computer aided design (CAD) software to capture images of the eclipse from the high altitude balloon. The light, durable, and water resistant mount consisted of a polyurethane-coated UV-resin based enclosure that housed six Hero 4 Session GoPro cameras, and a relative inertial measurement unit (IMU) PCB equipped with GPS. The cameras’ lenses faced radially outward on the six faces of a cube. The IMU/GPS PCB system computed the absolute orientation of the cameras, which allows the time-lapse pictures to be stitched together into a relatively stable spherical video. The batteries for this system experienced a voltage drop during flight as the payload temperature dropped below -60 degrees Celsius resulting in an auto-shutdown procedure disabling the system before eclipse totality. Future designs for this model will include a temperature regulation or insulation system to prevent this voltage drop

Observing the 2017 Total Solar Eclipse in the skies above Central Missouri, USA

We report the work and findings of Arkansas BalloonSAT in participating in the 2017 Eclipse Ballooning Project. Arkansas BalloonSAT was the site-team for Missouri and launched a high altitude balloon from Fulton High School in Fulton, MO an hour prior to totality. This balloon reached an apogee of 24 kilometers shortly after floating for one minute in the moon\u27s umbra. In addition to live-streaming video from one payload as part of the Eclipse Ballooning Project, our mission included carrying a scientific payload and educational outreach. This report will summarize those efforts and include an examination of balloon kinematics with the cooling effect of the moon\u27s umbra and aircraft-balloon interaction. We further discuss developments in the system to minimize payload size for future eclipse studies

Three-Dimensional (3D) In Vitro Cell Culture Protocols to Enhance Glioblastoma Research

Three-dimensional (3D) cell culture models can help bridge the gap between in vitro cell cultures and in vivo responses by more accurately simulating the natural in vivo environment, shape, tissue stiffness, stressors, gradients and cellular response while avoiding the costs and ethical concerns associated with animal models. The inclusion of the third dimension in 3D cell culture influences the spatial organization of cell surface receptors that interact with other cells and imposes physical restrictions on cells in compared to Two-dimensional (2D) cell cultures. Spheroids’ distinctive cyto-architecture mimics in vivo cellular structure, gene expression, metabolism, proliferation, oxygenation, nutrition absorption, waste excretion, and drug uptake while preserving cell–extracellular matrix (ECM) connections and communication, hence influencing molecular processes and cellular phenotypes. This protocol describes the in vitro generation of tumourspheroids using the low attachment plate, hanging drop plate, and cellusponge natural scaffold based methods. The expected results from these protocols confirmed the ability of all these methods to create uniform tumourspheres

The geometry of thermodynamic control

A deeper understanding of nonequilibrium phenomena is needed to reveal the principles governing natural and synthetic molecular machines. Recent work has shown that when a thermodynamic system is driven from equilibrium then, in the linear response regime, the space of controllable parameters has a Riemannian geometry induced by a generalized friction tensor. We exploit this geometric insight to construct closed-form expressions for minimal-dissipation protocols for a particle diffusing in a one dimensional harmonic potential, where the spring constant, inverse temperature, and trap location are adjusted simultaneously. These optimal protocols are geodesics on the Riemannian manifold, and reveal that this simple model has a surprisingly rich geometry. We test these optimal protocols via a numerical implementation of the Fokker-Planck equation and demonstrate that the friction tensor arises naturally from a first order expansion in temporal derivatives of the control parameters, without appealing directly to linear response theory

miR-199a-5p silencing regulates the unfolded protein response in chronic obstructive pulmonary disease and α1-antitrypsin deficiency.

RATIONALE: Retention of abnormal α1-antitrypsin (AAT) activates the unfolded protein response in AAT-deficient monocytes. The regulatory role of microRNAs (miRNAs) in unfolded protein responses and chronic obstructive pulmonary disease pathogenesis has not been investigated. OBJECTIVES: To investigate miRNA expression and function in MM and ZZ monocytes and identify miRNA(s) regulating the unfolded protein response. METHODS: Peripheral blood monocytes were isolated from asymptomatic and symptomatic MM and ZZ individuals for miRNA expression profiling and pyrosequencing analysis. miRNA/gene and protein expression was measured with quantitative polymerase chain reaction and Western blotting. Overexpression and inhibition studies were performed with pre-miR or anti-miR, respectively. Luciferase reporter genes were used to elucidate direct miRNA-target interactions. Inflammatory cytokines were detected using the Meso Scale Discovery Plex assays. MEASUREMENTS AND MAIN RESULTS: Forty-three miRNAs were differentially expressed, with miR-199a-5p most highly up-regulated in asymptomatic ZZ versus MM monocytes. miR-199a-2 promoter hypermethylation inhibits miR-199a-5p expression and was increased in symptomatic MM and ZZ monocytes compared with asymptomatic counterparts. GRP78, activating transcription factor 6, p50, and p65 were increased in symptomatic versus asymptomatic ZZ monocytes. Reciprocal down- or up-regulation of these markers was observed after miRNA modulation. Direct miR-199a-5p targeting of activating transcription factor 6, p50, and p65 by miR-199a-5p was demonstrated using luciferase reporter systems. Overexpression of miR-199a-5p also decreased other arms of the UPR and expression of cytokines that are not putative targets. CONCLUSIONS: miR-199a-5p is a key regulator of the unfolded protein response in AAT-deficient monocytes, and epigenetic silencing of its expression regulates this process in chronic obstructive pulmonary disease

Perceived agency mediates the link between the narcissistic subtypes and self-esteem

a b s t r a c t a r t i c l e i n f o Grandiose and vulnerable narcissism share some core features (e.g., entitlement, self-absorption) but differ in other important ways (e.g., self-esteem). To reconcile these differing characteristics, we predicted that differences in perceived agency mediate the association between narcissistic subtypes and differences in selfesteem. One hundred college students completed self-report measures of grandiose narcissism, vulnerable narcissism, explicit global self-esteem, and perceived agency. As predicted, grandiose narcissism was positively associated with agency and self-esteem, whereas vulnerable narcissism was negatively associated with agency and self-esteem. Perceived agency also mediated the associations between each narcissistic subtype and selfesteem. Furthermore, a partial correlation showed that when controlling for agency, the previously null correlation between measures of grandiose and vulnerable narcissism became significantly positive. These findings indicate that agency serves as a primary differentiator between the narcissistic subtypes