Thermodynamics of Water Dimer Dissociation in the Primary Hydration Shell of the Iodide Ion with Temperature-Dependent Vibrational Predissociation Spectroscopy

2015 ◽  
Vol 119 (10) ◽  
pp. 1859-1866 ◽  
Author(s):  
Conrad T. Wolke ◽  
Fabian S. Menges ◽  
Niklas Tötsch ◽  
Olga Gorlova ◽  
Joseph A. Fournier ◽  
...  
Keyword(s):  
Hydration Shell ◽  
Water Dimer ◽  
Temperature Dependent ◽  
Vibrational Predissociation ◽  
Iodide Ion

scholarly journals Hyaluronan orders water molecules in its nanoscale extended hydration shells

2021 ◽  
Vol 7 (10) ◽  
pp. eabf2558
Author(s):  
J. Dedic ◽  
H. I. Okur ◽  
S. Roke
Keyword(s):  
Second Harmonic ◽  
Hydration Shell ◽  
Water Molecules ◽  
Temperature Dependent ◽  
Flexible Chain ◽  
Optical Modeling ◽  
Hydration Shells ◽  
Second Harmonic Scattering ◽  
Nuclear Quantum Effects ◽  
Extracellular Environment

Hyaluronan (HA) is an anionic, highly hydrated bio-polyelectrolyte found in the extracellular environment, like the synovial fluid between joints. We explore the extended hydration shell structure of HA in water using femtosecond elastic second-harmonic scattering (fs-ESHS). HA enhances orientational water-water correlations. Angle-resolved fs-ESHS measurements and nonlinear optical modeling show that HA behaves like a flexible chain surrounded by extended shells of orientationally correlated water. We describe several ways to determine the concentration-dependent size and shape of a polyelectrolyte in water, using the amount of water oriented by the polyelectrolyte charges as a contrast agent. The spatial extent of the hydration shell is determined via temperature-dependent measurements and can reach up to 475 nm, corresponding to a length of 1600 water molecules. A strong isotope effect, stemming from nuclear quantum effects, is observed when light water (H2O) is replaced by heavy water (D2O), amounting to a factor of 4.3 in the scattered SH intensity.

Vibrational predissociation of the phenol–water dimer: a view from the water

2019 ◽  
Vol 21 (26) ◽  
pp. 13968-13976 ◽  
Author(s):  
Daniel Kwasniewski ◽  
Mitchell Butler ◽  
Hanna Reisler
Keyword(s):  
Internal State ◽  
Water Dimer ◽  
Vibrational Predissociation ◽  
Phenol Water

Predissociation dynamics of the phenol–water dimer were studied by detecting H2O fragments and using VMI to infer internal state distributions.

Temperature-dependent near-infrared spectroscopy for studying the interactions in protein aqueous solutions

NIR news ◽  
2019 ◽  
Vol 30 (5-6) ◽  
pp. 15-17
Author(s):  
Mian Wang ◽  
Xiaoyu Cui ◽  
Wensheng Cai ◽  
Xueguang Shao
Keyword(s):  
Infrared Spectroscopy ◽  
Aqueous Solutions ◽  
Near Infrared Spectroscopy ◽  
Structural Changes ◽  
Near Infrared ◽  
Molten Globule ◽  
Hydration Shell ◽  
Protein S ◽  
Temperature Dependent ◽  
Water Species

Temperature-dependent near-infrared spectroscopy has been developed for studying quantitative and structural analysis, as well as the molecular interactions. Taking the advantage of the temperature effect on hydrogen bonding, the technique has shown its potential in analyzing the interactions in aqueous solutions. In our recent studies, the structural changes in homo-oligopeptides K5 (penta-lysine), D5 (penta-aspartic acid), and protein (ovalbumin) aqueous solutions were studied by temperature-dependent near-infrared spectroscopy. The thermodynamics and their interaction with water were analyzed with the help of the chemometric methods including continuous wavelet transform, independent component analysis, two-dimensional (2D) correlation analysis, and Gaussian fitting. The results show that the oligopeptide in aqueous solution improves the thermal stability of the water species, and K5 has stronger interaction with water than D5. In the gelation of ovalbumin, the change of the water species with two hydrogen bonds (S2) follows the same phases as the protein. S2 maintains the stability of the protein in native and molten globule states, and the weakening of the hydrogen bond in S2 by high temperature results in the destruction of the hydration shell and makes the ovalbumin clusters form a gel structure.

(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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