Advanced Practical Holography: In situ Instant Holographic Interferometry on Silver Halide Media Without Liquid Gates or Repositioning of the Media

In recent years, Metal-Organic Frameworks (MOFs) have attracted a growing interest for biomedical applications. The design of MOFs should take into consideration the subtle balance between stability and biodegradability. However, only few studies have focused on the MOFs’ stability in physiological media and their degradation mechanism. Here, we investigate the degradation of mesoporous iron (III) carboxylate MOFs, which are among the most employed MOFs for drug delivery, by a set of complementary methods. In situ AFM allowed monitoring with nanoscale resolution the morphological, dimensional, and mechanical properties of a series of MOFs in phosphate buffer saline and in real time. Depending on the synthetic route, the external surface presented either well-defined crystalline planes or initial defects, which influenced the degradation mechanism of the particles. Moreover, MOF stability was investigated under different pH conditions, from acidic to neutral. Interestingly, despite pronounced erosion, especially at neutral pH, the dimensions of the crystals were unchanged. It was revealed that the external surfaces of MOF crystals rapidly respond to in situ changes of the composition of the media they are in contact with. These observations are of a crucial importance for the design of nanosized MOFs for drug delivery applications.

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The lowest energy excited states of the binuclear silver(I) halide complexes, Ag2(dmb)2X2. Metal-centered or charge transfer states?

Canadian Journal of Chemistry ◽

10.1139/v94-095 ◽

1994 ◽

Vol 72 (3) ◽

pp. 705-713 ◽

Cited By ~ 14

Author(s):

Daniel Piché ◽

Pierre D. Harvey

Keyword(s):

Charge Transfer ◽

Solid State ◽

Excited States ◽

Silver Halide ◽

Molecular Orbital Calculations ◽

Isocyanide Ligands ◽

Visible Spectra ◽

Halide Complexes ◽

The Media ◽

Uv Visible

The nature of the lowest energy excited states of the Ag2(dmb)2X2 complexes (X = Cl, Br, I; dmb = 1,8-diisocyano-ρ-menthane) have been addressed both experimentally and theoretically. It is shown that the lowest energy excited states of the complexes are charge transfer states from the silver-halide frame to the isocyanide ligands (M/XLCT) based upon UV-visible spectra and emission polarization ratio measurements, and extended Hückel molecular orbital calculations (EHMO). The metal-centered dσ* → pσ bands have been observed in the higher energy region of the spectra (232–242 nm). The complexes are luminescent (440 ≤ λe ≤ 480 nm) both in a glass and in the solid state at 77 K where the emission lifetimes, τe, range from 20 to 90 µs, which depend upon the nature of the halide (for the solid state data) and the media. No emission is observed at room temperature.

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Implantation in Coronary Circulation Induces Morphofunctional Transformation of Radial Grafts From Muscular to Elastomuscular

Circulation ◽

10.1161/circulationaha.104.512889 ◽

2005 ◽

Vol 112 (9_supplement) ◽

Author(s):

Mario Gaudino ◽

Francesco Prati ◽

Eugenio Caradonna ◽

Carlo Trani ◽

Francesco Burzotta ◽

...

Keyword(s):

Internal Thoracic Artery ◽

Coronary Circulation ◽

Ultrasound Examination ◽

Artery Bypass ◽

Elastic Tissue ◽

The Media ◽

The Mean ◽

Muscular Architecture

Background— The purpose of this research was to investigate the in vivo morphofunctional changes induced in the radial artery (RA) by its use as coronary artery bypass conduit by comparing the morphological features and vasoreactivity of the native RA versus the coronary RA graft in the same patient. Methods and Results— Ten years after surgery, 10 patients were submitted to intravascular ultrasound examination of the RA graft of the controlateral (in situ) RA and of the internal thoracic artery (ITA) graft and to vasoactive challenges with acetylcholine and serotonin. Quantitative angiographic assessment showed that the mean diameter of the RA coronary grafts was significantly larger than that of the in situ RA and of the ITA (2.89±0.40 mm RA grafts, 2.14±0.52 mm in situ RA, 2.25±0.53 mm ITA grafts; P <0.001). The in situ RA demonstrated a typical muscular architecture, whereas RA coronary grafts showed a clear reduction of the thickness of the medial layer and had a less well-defined muscular component of the media with interposition of elastic tissue. Serotonin endovascular infusion elicited a strong spastic reaction in in situ RAs; the same challenge induced only moderate constriction in RA and ITA coronary grafts. Conclusions— Implantation in the coronary circulation leads to major anatomic and vasoreactive modifications of the RAs that tend to lose the morphofunctional features of a muscular conduit and assume those of an elastomuscular artery, such as the ITA.

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In Situ Sensing of Volatile Organic Compounds in Groundwater: First Field Tests of a Mid-Infrared Fiber-Optic Sensing System

Applied Spectroscopy ◽

10.1366/000370203322005274 ◽

2003 ◽

Vol 57 (6) ◽

pp. 607-613 ◽

Cited By ~ 33

Author(s):

H. Steiner ◽

M. Jakusch ◽

M. Kraft ◽

M. Karlowatz ◽

T. Baumann ◽

...

Keyword(s):

Real World ◽

Fiber Optic ◽

Silver Halide ◽

Field Tests ◽

Reference Analysis ◽

Mid Infrared ◽

Sensor Head ◽

Aquifer System ◽

Volatile Organic

A prototype mid-infrared sensor system for the determination of volatile organic pollutants in groundwater was developed and tested under real-world conditions. The sensor comprises a portable Fourier transform infrared spectrometer, coupled to the sensor head via mid-infrared transparent silver halide fiber-optic cables. A 10 cm unclad middle section of the 6-m-long fiber is coated with ethylene propylene copolymer in order to enrich the analytes within the penetration depth of the evanescent field protruding from the fiber sensor head. A mixture of tetrachloroethylene, dichlorobenzene, diethyl phthalate, and xylene isomers at concentrations in the low ppm region was investigated qualitatively and quantitatively in an artificial aquifer system filled with Munich gravel. This simulated real-world site at a pilot scale enables in situ studies of the sensor response and spreading of the pollutants injected into the system with controlled groundwater flow. The sensor head was immersed into a monitoring well of the aquifer system at a distance of 1 m downstream of the sample inlet and at a depth of 30 cm. Within one hour, the analytes were clearly identified in the fingerprint region of the IR spectrum (1300 to 700 cm−1). The results have been validated by head-space gas chromatography, using samples collected during the field measurement. Five out of six analytes could be discriminated simultaneously; for two of the analytes the quantitative results are in agreement with the reference analysis.

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Formation and remediation simulation of an in-situ reactive zone with nanoiron for a nitrobenzene-contaminated aquifer

Water Science & Technology Water Supply ◽

10.2166/ws.2018.034 ◽

2018 ◽

Vol 18 (6) ◽

pp. 2071-2080

Author(s):

Li Hui ◽

Zhang Xue-qing

Keyword(s):

Fine Sand ◽

Coarse Sand ◽

Water Yield ◽

Permeability Change ◽

Contaminated Aquifer ◽

Permeability Constant ◽

Sand Box ◽

Reactive Zone ◽

The Media

Abstract A two-dimensional simulated sand box was built to investigate the formation and remediation of an in-situ reactive zone (IRZ) of nanoscale zero-valent iron (NZVI) for a nitrobenzene-contaminated aquifer, and the permeability change of the zone was calculated through the loss of waterhead. The experimental results demonstrated that the remediation area in coarse sand was obviously larger than that in fine sand. The nitrobenzene concentration reached a stable level of 87.24 and 170.24 mg/L in coarse and fine sand by 50 d and 40 d, respectively; after 60 d, the concentration of aniline as the reduction end-product of nitrobenzene was 97.02 and 49.40 mg/L, corresponding to a mean production rate of 40.1% and 20.8%, respectively. This indicated that a wider zone will be formed in the media with a larger size, which is beneficial for pollution remediation. The water yield of the aquifer declined by 13.8% and 11.9% in coarse and fine sand after 60 d, and the final permeability constant was 22.94 and 1.82 m/d (declining by 60.9% and 70.6%), respectively. The reactive zone remained stable and the injection of NZVI slurry could not cause any dramatic changes in the aquifer permeability.

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