Hubert van den Bergh

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A 351-363 nm wavelength argon laser is used to induce pyrolytic laser chem. vapor deposition of platinum, using platinum bishexafluoroacetylacetonate as a precursor. The deposit thicknesses and diams. are presented according to exposure time, precursor pressure, and laser spot diam. Calcn. of the temp. induced by the laser radiation exposure by using a method developed allows one to study the kinetics of the deposition process which takes place either under a regimen controlled by the diffusion of the react

Background: Photodynamic therapy (PDT) at low drug-light conditions can enhance the transport of intravenously injected macromolecular therapeutics through the tumor vasculature. Here we determined the impact of PDT on the distribution of liposomal doxorub ...

In photodynamic therapy (PDT), excitation of a drug by light leads to a cascade of biochemical processes that can cause closure of blood vessels. It has been observed clinically that significant short-term leakage from the irradiated vasculature can occur ...

Hexyl aminolevulinate (HAL) fluorescence cystoscopy is being investigated as a new diagnostic tool for the detection of flat urothelial malignancies in bladder cancers. However, the influence of the bladder instillation time on the performance of this detection modality has not been addressed up to now. We report our initial experience comparing different instillation schedules of HAL cystoscopy in the diagnosis of superficial bladder cancer. A total of 718 fluorescent positive (433) and fluorescence negati

A computer simulation of some chem. scenarios are presented to obtain preliminary information on what can be learned from pump-and-probe lidar expts., i.e., in situ laser flash photolysis in the troposphere. The decay of the OH concn. following the flash photolysis by different spatially resolved techniques is done under different conditions where the significant chem. and meteorol. parameters were sep. measured, so that model calcs. can be compared with time-dependent OH concns. The scenarios, within the l

An episode selection procedure was developed and applied to select sets of days representing characteristic meteorol. conditions leading to high ozone episodes over the Swiss Plateau. The selection procedure was applied to data extending from Jan. 1991 through Dec. 1998, and is comprised of two steps: First, days were classified according to obsd. air quality and meteorol. characteristics using classification and regression trees anal. (CART). Second, the CART results were used in conjunction with obsd. air

Forecasts for the NOx concentration levels in the Greater Athens area in 2004 are compared to the corresponding figures for 1990. Simulations are performed for two meteorological cases using four different dispersion models. Two different emission inventories are employed in the simulations. The first is based on the conditions for the year 1990, while the second is the reference scenario for the year 2004, taking into account all major public works under construction. In order to ensure the validity of the

Autofluorescence (AF) bronchoscopy is a useful tool for early cancer detection. However the mechanisms involved in this diagnosis procedure are poorly understood. We present a clinical autofluorescence imaging study to assess the depth of the principal contrast mechanisms within the bronchial tissue comparing a narrowband (superficial) and broadband (penetrating) violet excitation. Knowledge of this parameter is crucial for the optimization of the spectral and optical design of clinical diagnostic AF imagin

Cancer, when detected at an early stage, has a very good probability of being eradicated by surgery or radiotherapy. However, less aggressive treatments also tend to provide high rates of cure without the side effects of radical therapy. We report on the r ...

Laser-induced CVD has been used to produce Pt lines on pyrex glass substrates by means of platinum bis(hexafluoroacetylacetonate) as precursor. The effect that writing speed has on the line geometry and resistivity was studied, as well as the influence of writing speed, precursor vapor pressure, and laser power on periodic structure formation. The results are discussed in terms of laser beam residence time and radiation-induced temp. increase. It is possible to obtain lines with a resistivity very close to

Mixts. of methane, H, and Ar (CH4:H2:Ar) were studied as UV Raman shifters for ozone differential absorption lidar application. They have higher photochem. stability than pure CH4 and the capability to produce, with high enough efficiency, either 1st CH4 Stokes or, simultaneously, CH4 and H2 1st Stokes with equal energies. These mixts. can be used as an inexpensive replacement for D2 or a more stable substitute for pure CH4 in single-pass high-power Raman shifters.

The reaction I2M + hn -> I2(B) + M (M = H, N, O, I) was studied following excitation of the I2M cluster above its B state dissocn. limit. Dispersion of the I fluorescence allows for the detn. of the relative populations of a no. of the vibrational levels v' of the B state. The relative importance of the hindered dissocn. pathway appears to increase with decreasing photon energy as compared to the alternative (unobserved) path in which the I-I bond is broken, and the photofragment recoil energy tends to incr

The influence of the time interval between dye administration and detection by fluorescence microscopy was assessed in "early" squamous cell carcinomas of the cheek pouch mucosa and different healthy tissues of the Syrian hamster. Following intracardiac ...

The heterogeneous reactions of NO3 on NaCl and KBr salt were studied at room temp. using a Knudsen reactor equipped with dual detection, namely Laser induced fluorescence and mass spectrometry. The uptake coeffs. of NO3 were g=(4.9+-3).10-2 onto NaCl and g=0.16+-0.08 onto KBr. In the case of NaCl, HCl was the sole product obsd. However, there is indirect evidence that Cl atoms are the primary products. In the case of KBr we obsd. Br2 and Br to be the products of reaction. A first estn. of the atm. relevance

To test and optimize photodynamic therapy of early cancers in the upper aero-digestive tract and esophagus, we sought an appropriate animal model, which was found in the 7,12-dimethylbenz[a]anthracene-induced early squamous cell carcinoma in the Golden Syrian hamster. This chem. induced neoplasm is shown, by histol. and immunohistochem., to pass through similar stages of early cancer development as its human counterpart. Its time sequence is highly reproducible, leading to a well differentiated carcinoma in

The recombination of I atoms after laser flash photolysis was studied in the presence of NO or NO2 at 320-450 DegK and 0-200 atm of He. The reaction proceeds in 2 stages. The 1st stage is governed by the recombination I + NO (+He) -> INO (+He) or I + NO2 (+He) -> INO2 (+He), for which the full falloff curves are derived. The 2nd stage is governed either by reaction between 2 INO (or INO2) mols., or, at higher temps., by thermal decompn. of INO (or INO2). The reaction involves the elementary steps of a typic

Formaldehyde is a primary and secondary air pollutant. As an intermediate product of hydrocarbon photooxidn., it contributes to the formation of photochem. pollution in urban areas. In addn., chronic or acute exposure to HCHO (a possible carcinogen) constitutes an important health hazard. Differential optical absorption spectroscopy (DOAS) is one of the best-suited techniques for monitoring formaldehyde. Within the frame of a European Union project, a field measurement campaign (PIPAPO) was carried out from

Fluorescence cystoscopy (FC) efficiently enhances the detection and improves the therapeutic management of early bladder cancer. During an FC, about 150 ml of water is needed to inflate the bladder. The water is quickly diluted by urine which can be fluore ...

The recombination of I atoms in the presence of NO was studied by laser flash photolysis in the inert gas He, at pressures between 1 and 200 atm and at temps. from 320-440 DegK. The elementary steps of the complex mechanism of the recombination were resolved. The fall-off curve of the interaction I + NO + He -> INO + He was measured as well as the equil. const. for I + NO .tautm. INO. The bond energy of INO is DH00 = 23 +- 3 kcal mole-1.

Spin-coated solid films of the gold-cluster compd. dodeca-(triphenylphosphine), hexa(chloro)pentapentacontagold Au55(PPh3)12Cl6 are irradiated with a focused 20-keV Ga+ focused-ion beam. Writing speeds on the substrate ranged from 50 up to 2000 mm/s. This treatment locally decreases the soly. of the metalorg. precursor layer in CH2Cl2. Removal of the nonirradiated part of the surface layer with this solvent, followed by thermal decompn. of the remaining metalorg. nanostructures, leads to conducting gold lin

Hubert van den Bergh

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Deposition kinetics of platinum small ohmic contacts and Schottky diodes

Photodynamic therapy enhances liposomal doxorubicin distribution in tumors during isolated perfusion of rodent lungs

Combination therapy using aspirin-enhanced photodynamic selective drug delivery

On the influence of the instillation time on the results of HAL (Hexvix®) fluorescence detection of superficial bladder cancer

Pump-and-probe lidar for in-situ probing of atmospheric chemistry

Episode selection for ozone modelling and control strategies analysis on the Swiss Plateau

Forecasting air quality in the Greater Athens area for the year 2004: An intercomparison of the results of four different dispersion models

Improvement of the contrast in cancer detection by autofluorescence bronchoscopy using a narrow spectral violet excitation: A preliminary study

Photodynamic therapy for 101 early cancers of the upper aerodigestive tract, the esophagus, and the bronchi: a single-institution experience

Formation of platinum interconnection lines and periodic structures

Raman frequency shifting in a CH4:H2:Ar mixture pumped by the fourth harmonic of a Nd:YAG laser

Solvent caging by diatomic molecules in the photodissociation of molecular iodine-diatomic molecule (I2M) clusters

Measurements by fluorescence microscopy of the time-dependent distribution of meso-tetra-hydroxyphenylchlorin in healthy tissues and chemically induced ''early'' squamous cell carcinoma of the Syrian hamster cheek pouch

The heterogeneous reaction of NO3 with NaCl and KBr: a nonphotolytic source of halogen atoms

7,12-Dimethylbenz[a]anthracene-induced 'early' squamous cell carcinoma in the Golden Syrian hamster: evaluation of an animal model and comparison with 'early' forms of human squamous cell carcinoma in the upper aero-digestive tract

Kinetic and thermodynamic properties of nitrosyl iodide and nitryl iodide intermediate complexes in iodine recombination

Measurement of formaldehyde (HCHO) by DOAS: intercomparison to DNPH measurements and interpretation from Eulerian model calculations

Study of the influence of over-the-counter vitamin supplement intake on urine fluorescence to optimize cancer detection by fluorescence cystoscopy

Nitrogen oxide-catalyzed recombination of iodine atoms. Elementary steps of the complex mechanism

Direct writing of gold nanostructures using a gold-cluster compound and a focused ion beam