Diffusion Tensor Phenomapping of the Healthy and Pressure-Overloaded Human Heart.

Current techniques to image the microstructure of the heart with diffusion tensor MRI (DTI) are highly under-resolved. We present a technique to improve the spatial resolution of cardiac DTI by almost 10-fold and leverage this to measure local gradients in cardiomyocyte alignment or helix angle (HA). We further introduce a phenomapping approach based on voxel-wise hierarchical clustering of these gradients to identify distinct microstructural microenvironments in the heart.

Role of miRNAs in sucrose stress response, reactive oxygen species, and anthocyanin biosynthesis in .

In plants, sucrose is the main transported disaccharide that is the primary product of photosynthesis and controls a multitude of aspects of the plant life cycle including structure, growth, development, and stress response. Sucrose is a signaling molecule facilitating various stress adaptations by crosstalk with other hormones, but the molecular mechanisms are not well understood. Accumulation of high sucrose concentrations is a hallmark of many abiotic and biotic stresses, resulting in the accumulation of reactive oxygen species and secondary metabolite anthocyanins that have antioxidant properties.

The role of microRNAs in responses to drought and heat stress in peanut (Arachis hypogaea).

MicroRNAs (miRNAs) are 21-24 nt small RNAs (sRNAs) that negatively regulate protein-coding genes and/or trigger phased small-interfering RNA (phasiRNA) production. Two thousand nine hundred miRNA families, of which ∼40 are deeply conserved, have been identified in ∼80 different plant species genomes. miRNA functions in response to abiotic stresses is less understood than their roles in development.

C2 and V2 are suppressors of post-transcriptional gene silencing.

Grapevine red blotch virus (GRBV) is the causative agent of grapevine red blotch disease (GRBD) which is one of the major threats faced by grapevine industry in the United States Since its initial identification in 2011, the disease has rapidly spread in the major US grape-growing regions of the Pacific Northwest, causing major economic impacts. Geminiviruses, the largest family of plant viruses, can induce and be targeted by host post-transcriptional gene-silencing (PTGS) anti-viral mechanisms. As a counter-defense mechanism, viruses have evolved viral silencing suppressor proteins to combat PTGS mechanisms and establish a successful infection in host plants.

Inhibition of advanced glycation end product formation and serum protein infiltration in bioprosthetic heart valve leaflets: Investigations of anti-glycation agents and anticalcification interactions with ethanol pretreatment.

Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol.

Poly-2-methyl-2-oxazoline-modified bioprosthetic heart valve leaflets have enhanced biocompatibility and resist structural degeneration.

Bioprosthetic heart valves (BHV) fabricated from glutaraldehyde-fixed heterograft tissue, such as bovine pericardium (BP), are widely used for treating heart valve disease, a group of disorders that affects millions. Structural valve degeneration (SVD) of BHV due to both calcification and the accumulation of advanced glycation end products (AGE) with associated serum proteins limits durability. We hypothesized that BP modified with poly-2-methyl-2-oxazoline (POZ) to inhibit protein entry would demonstrate reduced accumulation of AGE and serum proteins, mitigating SVD.

Electron Beam Melting of Niobium Alloys from Blended Powders.

Niobium-based tungsten alloys are desirable for high-temperature structural applications yet are restricted in practice by limited room-temperature ductility and fabricability. Powder bed fusion additive manufacturing is one technology that could be leveraged to process alloys with limited ductility, without the need for pre-alloying. A custom electron beam powder bed fusion machine was used to demonstrate the processability of blended Nb-1Zr, Nb-10W-1Zr-0.

Quasi-Static Tensile Properties of Unalloyed Copper Produced by Electron Beam Powder Bed Fusion Additive Manufacturing.

Mechanical properties of powder bed fusion processed unalloyed copper are reported majorly in the as-fabricated condition, and the effect of post-processes, common to additive manufacturing, is not well documented. In this study, mechanical properties of unalloyed copper processed by electron beam powder bed fusion are characterized via room temperature quasi-static uniaxial tensile test and Vickers microhardness. Tensile samples were extracted both perpendicular and parallel to the build direction and assigned to three different conditions: as-fabricated, hot isostatic pressing (HIP), and vacuum annealing.

Model studies of advanced glycation end product modification of heterograft biomaterials: The effects of in vitro glucose, glyoxal, and serum albumin on collagen structure and mechanical properties.

Glutaraldehyde cross-linked heterograft tissues, bovine pericardium (BP) or porcine aortic valves, are the leaflet materials in bioprosthetic heart valves (BHV) used in cardiac surgery for heart valve disease. BHV fail due to structural valve degeneration (SVD), often with calcification. Advanced glycation end products (AGE) are post-translational, non-enzymatic reaction products from sugars reducing proteins.

Glycation and Serum Albumin Infiltration Contribute to the Structural Degeneration of Bioprosthetic Heart Valves.

Valvular heart diseases are associated with significant cardiovascular morbidity and mortality, and often require surgical and/or percutaneous repair or replacement. Valve replacement is limited to mechanical and biological prostheses, the latter of which circumvent the need for lifelong anticoagulation but are subject to structural valve degeneration (SVD) and failure. Although calcification is heavily studied, noncalcific SVD, which represent roughly 30% of BHV failures, is relatively underinvestigated.

A role for in pineapple fruit development.

Chen ( . 51: 1549-1558; Oct. 2019) sequenced var.

CRISPR/Cas9-mediated targeted mutagenesis of TAS4 and MYBA7 loci in grapevine rootstock 101-14.

Pierce's disease (PD) of grapevine (Vitis vinifera) is caused by the bacterium Xylella fastidiosa and is vectored by xylem sap-sucking insects, whereas Grapevine Red Blotch Virus (GRBV) causes Red Blotch Disease and is transmitted in the laboratory by alfalfa leafhopper Spissistilus festinus. The significance of anthocyanin accumulations in distinct tissues of grapevine by these pathogens is unknown, but vector feeding preferences and olfactory cues from host anthocyanins may be important for these disease etiologies. Phosphate, sugar, and UV light are known to regulate anthocyanin accumulation via miR828 and Trans-Acting Small-interfering locus4 (TAS4), specifically in grape by production of phased TAS4a/b/c small-interfering RNAs that are differentially expressed and target MYBA5/6/7 transcription factor transcripts for post-transcriptional slicing and antisense-mediated silencing.

Efficient Cobalt Catalyst for Ambient-Temperature Nitrile Dihydroboration, the Elucidation of a Chelate-Assisted Borylation Mechanism, and a New Synthetic Route to Amides.

,-Diborylamines have emerged as promising reagents in organic synthesis; however, their efficient preparation and full synthetic utility have yet to be realized. To address both shortcomings, an effective catalyst for nitrile dihydroboration was sought. Heating CoCl in the presence of PDI afforded the six-coordinate Co(II) salt, [(PDI)CoCl][Cl].

The Role of UV-B light on Small RNA Activity During Grapevine Berry Development.

We explored the effects of ultraviolet B radiation (UV-B) on the developmental dynamics of microRNAs and phased small-interfering-RNA (phasi-RNAs)-producing loci by sequencing small RNAs in vegetative and reproductive organs of grapevine ( L.). In particular, we tested different UV-B conditions in -grown plantlets (high-fluence exposition) and in berries from field-grown (radiation filtering) and greenhouse-grown (low- and high-fluence expositions) adult plants throughout fruit development and ripening.

Anti-Markovnikov terminal and gem-olefin hydrosilylation using a κ-diimine nickel catalyst: selectivity for alkene hydrosilylation over ether C-O bond cleavage.

The phosphine-substituted α-diimine Ni precursor, (Ph2PPrDI)Ni, has been found to catalyze alkene hydrosilylation in the presence of Ph2SiH2 with turnover frequencies of up to 124 h-1 at 25 °C (990 h-1 at 60 °C). Moreover, the selective hydrosilylation of allylic and vinylic ethers has been demonstrated, even though (Ph2PPrDI)Ni is known to catalyze allyl ester C-O bond hydrosilylation. At 70 °C, this catalyst has been found to mediate the hydrosilylation of ten different gem-olefins, with turnover numbers of up to 740 under neat conditions.

Carbonyl and ester C-O bond hydrosilylation using κ-diimine nickel catalysts.

The synthesis of alkylphosphine-substituted α-diimine (DI) ligands and their subsequent addition to Ni(COD)2 allowed for the preparation of (iPr2PPrDI)Ni and (tBu2PPrDI)Ni. The solid state structures of both compounds were found to feature a distorted tetrahedral geometry that is largely consistent with the reported structure of the diphenylphosphine-substituted variant, (Ph2PPrDI)Ni. To explore and optimize the synthetic utility of this catalyst class, all three compounds were screened for benzaldehyde hydrosilylation activity at 1.

Hydroboration of alkynes and nitriles using an α-diimine cobalt hydride catalyst.

Addition of NaEtBH to (DI)CoCl affords the corresponding monohydride, (DI)CoH. X-ray diffraction and DFT calculations indicate that this compound possesses a radical monoanion α-DI chelate and a Co(ii) centre. Notably, (DI)CoH catalyzes the hydroboration of alkynes and dihydroboration of nitriles under mild conditions.

Mechanistic Investigation of Bis(imino)pyridine Manganese Catalyzed Carbonyl and Carboxylate Hydrosilylation.

We recently reported a bis(imino)pyridine (or pyridine diimine, PDI) manganese precatalyst, (PDI)Mn (1), that is active for the hydrosilylation of ketones and dihydrosilylation of esters. In this contribution, we reveal an expanded scope for 1-mediated hydrosilylation and propose two different mechanisms through which catalysis is achieved. Aldehyde hydrosilylation turnover frequencies (TOFs) of up to 4900 min have been realized, the highest reported for first row metal-catalyzed carbonyl hydrosilylation.

Biomechanical Properties of Fiber Bundle and Membrane Mesostructures of the Porcine Aortic Valve.

BACKGROUND AND AIM OF THE STUDY: Aortic valve leaflets have a complex, anisotropic structure that likely plays an important role in their biomechanical function. The larger scale (bulk) biomechanical properties of the valve have been well documented. However, limited data are available regarding the biomechanical properties of individual fiber bundles and membranes that connect the bundles.

AtRAV1 and AtRAV2 overexpression in cotton increases fiber length differentially under drought stress and delays flowering.

There is a longstanding problem of an inverse relationship between cotton fiber qualities versus high yields. To better understand drought stress signaling and adaptation in cotton (Gossypium hirsutum) fiber development, we expressed the Arabidopsis transcription factors RELATED_TO_ABA-INSENSITIVE3/VIVIPAROUS1/(RAV1) and AtRAV2, which encode APETALA2-Basic3 domain proteins shown to repress transcription of FLOWERING_LOCUS_T (FT) and to promote stomatal opening cell-autonomously. In three years of field trials, we show that AtRAV1 and AtRAV2-overexpressing cotton had ∼5% significantly longer fibers with only marginal decreases in yields under well-watered or drought stress conditions that resulted in 40-60% yield penalties and 3-7% fiber length penalties in control plants.

TOPOISOMERASE 6B is involved in chromatin remodelling associated with control of carbon partitioning into secondary metabolites and cell walls, and epidermal morphogenesis in Arabidopsis.

Plant growth is continuous and modular, a combination that allows morphogenesis by cell division and elongation and serves to facilitate adaptation to changing environments. The pleiotropic phenotypes of the harlequin (hlq) mutant, isolated on the basis of ectopic expression of the abscisic acid (ABA)- and auxin-inducible proDc3:GUS reporter gene, were previously characterized. Mutants are skotomorphogenic, have deformed and collapsed epidermal cells which accumulate callose and starch, cell walls abundant in pectins and cell wall proteins, and abnormal and reduced root hairs and leaf trichomes.

Related to ABA-Insensitive3(ABI3)/Viviparous1 and AtABI5 transcription factor coexpression in cotton enhances drought stress adaptation.

Drought tolerance is an important trait being pursued by the agbiotech industry. Abscisic acid (ABA) is a stress hormone that mediates a multitude of processes in growth and development, water use efficiency (WUE) and gene expression during seed development and in response to environmental stresses. Arabidopsis B3-domain transcription factor Related to ABA-Insensitive3 (ABI3)/Viviparous1 (namely AtRAV2) and basic leucine zipper (bZIPs) AtABI5 or AtABF3 transactivated ABA-inducible promoter:GUS reporter expression in a maize mesophyll protoplast transient assay and showed synergies in reporter transactivation when coexpressed.

Complex collagen fiber and membrane morphologies of the whole porcine aortic valve.

Objectives: Replacement aortic valves endeavor to mimic native valve function at the organ, tissue, and in the case of bioprosthetic valves, the cellular levels. There is a wealth of information about valve macro and micro structure; however, there presently is limited information on the morphology of the whole valve fiber architecture. The objective of this study was to provide qualitative and quantitative analyses of whole valve and leaflet fiber bundle branching patterns using a novel imaging system.

Trans-acting small interfering RNA4: key to nutraceutical synthesis in grape development?

The facility and versatility of microRNAs (miRNAs) to evolve and change likely underlies how they have become dominant constituents of eukaryotic genomes. In this opinion article I propose that trans-acting small interfering RNA gene 4 (TAS4) evolution may be important for biosynthesis of polyphenolics, arbuscular symbiosis, and bacterial pathogen etiologies. Expression-based and phylogenetic evidence shows that TAS4 targets two novel grape (Vitis vinifera L.

Jacalin lectin At5g28520 is regulated by ABA and miR846.

Plant microRNAs (miRNAs) are important regulators of development and stress responses and are oftentimes under transcriptional regulation by stresses and plant hormones. We recently showed that polycistronic MIR842 and MIR846 are expressed from the same primary transcript which is subject to alternative splicing. ABA treatment affects the alternative splicing of the primary cistronic transcript which results in differential expression of the two miRNAs that are predicted to target the same family of jacalin lectin genes.