Oleylamine Impurities Regulate Temperature-Dependent Hierarchical Assembly of Ultranarrow Gold Nanowires on Biotemplated Interfaces

ACS Nano ◽  
2021 ◽  
Author(s):  
Erin N. Lang ◽  
Ashlin G. Porter ◽  
Tianhong Ouyang ◽  
Anni Shi ◽  
Tyler R. Hayes ◽  
...  
Keyword(s):  
Gold Nanowires ◽  
Temperature Dependent ◽  
Hierarchical Assembly

scholarly journals Hierarchical assembly of the MLL1 core complex within a biomolecular condensate regulates H3K4 methylation

2019 ◽  
Author(s):  
Kevin E.W. Namitz ◽  
Song Tan ◽  
Michael S. Cosgrove
Keyword(s):  
Histone H3 ◽  
Maximal Activity ◽  
Domain Model ◽  
Kinetic Properties ◽  
H3k4 Methylation ◽  
Core Complex ◽  
Temperature Dependent ◽  
Hierarchical Assembly ◽  
Spatiotemporal Control ◽  
Eukaryotic Genomes

ABSTRACTThe enzymes that regulate histone H3 lysine 4 (H3K4) methylation are required for cellular differentiation and development and are often mutated in human disease. Mixed Lineage Leukemia protein-1 (MLL1) is a member of the SET1 family of histone H3 lysine 4 methyltransferases, which require interaction with a conserved sub-complex consisting of WDR5, RbBP5, Ash2L and DPY30 (WRAD2) for maximal activity. It is currently unclear how assembly of SET1 family complexes is involved in the spatiotemporal control of H3K4 methylation in eukaryotic genomes. In this investigation, we systematically characterized the hydrodynamic and kinetic properties of a reconstituted human MLL1 core complex and found that its assembly is highly concentration and temperature dependent. Consistent with a hierarchical assembly pathway, we found that the holo-complex assembles through interactions between the MW and RAD2 sub-complexes, which is correlated with enzymatic activity. Surprisingly, we found that the disassembled state is favored at physiological temperatures, and that this thermodynamic barrier can be overcome under conditions that induce high-local concentrations of subunits in phase separated compartments. Combining this data with the observation that MLL1 primary sequence contains large regions of intrinsic disorder, we propose a “swinging-domain” model in which the interaction between a tethered MW subcomplex and multiple nucleosome-RAD2 complexes is regulated by the rapid formation or dissolution of biomolecular condensates, such as occurs in transcription factories. This model provides an elegant “switch-like” mechanism for spatiotemporal control of H3K4 methylation within eukaryotic genomes.

scholarly journals Fabrication and temperature-dependent electrical characterization of a C-shape nanowire patterned by a DNA origami

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Türkan Bayrak ◽  
Amanda Martinez-Reyes ◽  
David Daniel Ruiz Arce ◽  
Jeffrey Kelling ◽  
Enrique C Samano ◽  
...  
Keyword(s):  
Self Assembly ◽  
Electroless Deposition ◽  
Electrical Characterization ◽  
Dna Origami ◽  
Gold Nanowires ◽  
Transport Mechanisms ◽  
Temperature Dependent ◽  
Weakly Coupled ◽  
Different Temperatures

AbstractWe introduce a method based on directed molecular self-assembly to manufacture and electrically characterise C-shape gold nanowires which clearly deviate from typical linear shape due to the design of the template guiding the assembly. To this end, gold nanoparticles are arranged in the desired shape on a DNA-origami template and enhanced to form a continuous wire through electroless deposition. C-shape nanowires with a size below 150nm on a $${\hbox {SiO}_2}/\hbox {Si}$$ SiO 2 / Si substrate are contacted with gold electrodes by means of electron beam lithography. Charge transport measurements of the nanowires show hopping, thermionic and tunneling transports at different temperatures in the 4.2K to 293K range. The different transport mechanisms indicate that the C-shape nanowires consist of metallic segments which are weakly coupled along the wires.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

In Vitro Effects of Urokinase — Prevention by Different Inhibitors

1990 ◽  
Vol 64 (03) ◽  
pp. 402-406 ◽  
Author(s):  
M D Oethinger ◽  
E Seifried
Keyword(s):  
In Vitro Study ◽  
Thrombin Time ◽  
Plasma Samples ◽  
Temperature Dependent ◽  
Chloromethyl Ketone ◽  
Control Value ◽  
Dose Time ◽  
In Vitro Effects ◽  
Full Protection

SummaryThe present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activato(u-PA, urokinase) on normal citrated plasma. When 10 μg/ml u-PA wereadded to pooled normal plasma and incubated for 30 min at an ambient temperature (25° C), α2-antiplas-min decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control,whereas α2-antiplasmin was fully consumed at 37° C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25° C. Thrombin time prolonged to 190% of control.Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KlU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection ofα2-antiplasmin at therapeutic levels of u-PA.It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.

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