We studied the incidence of leukemia cutis (LC) in 381 consecutive patients with acute myeloid le... more We studied the incidence of leukemia cutis (LC) in 381 consecutive patients with acute myeloid leu-kemia (AML) in a single institution and compared the demographic, hematological, and cytogenetic findings in AML patients with and without LC. We also examined the response to intensive chemotherapy, overall survival, and duration of remission in this patient population with regard to the presence of LC. The prevalence of LC was 3.7% in clinically diagnosed patients and 2.9% in biopsy proven cases, respectively. Patients with and without LC did not differ with regard to age, sex, white blood cell counts, hemoglobin, fibrinogen, and platelet counts at diagnosis, but lactate dehydrogenase (LDH) was significantly higher in patients with LC. Various karyotype abnormalities were found, but in patients with LC numerical abnormalities of chromosome 8 were significantly more common (P<0.0001). Patients with LC did not differ from patients without LC with regard to remission rate, but there was a trend towards shorter remission duration in patients with LC. We conclude that patients with LC have some features different from patients without this symptom. The increased frequency of numerical aberrations of chromosome 8 in patients with LC was the most interesting observation of our study. The patho-physiological significance of this finding remains to be determined.
A tumour cloning system was used to cultivate breast cancer specimens. Fifty-six percent of 87 sa... more A tumour cloning system was used to cultivate breast cancer specimens. Fifty-six percent of 87 samples were adequate for evaluation, showing clonal growth in about one third (35%). Effusions yielded significantly better growth than solid specimens, the median colony numbers being 64 and 18 respectively. An attempt was made to examine whether there was any association between parameters accepted as prognostic factors for breast cancer and clonal growth in vitro. No correlation was found between preoperative tumour burden, histopathologic grading, menopausal status or overall survival and clonal growth in vitro, whereas we observed an inverse trend between progesterone receptor content of the tumours and their growth potential (P less than 0.01). In those few cases where in vitro and in vivo data could be compared, a high accuracy of the predicted sensitivities was found with respect to chemotherapy, but not in relation to hormonal treatment. A statistically significant higher overall...
An electrochemical double-layer capacitor for high power applications is being developed at the P... more An electrochemical double-layer capacitor for high power applications is being developed at the Paul Scherrer Institute. Glassy carbon was chosen as electrode material because of its inertness, its good bulk conductivity, and the possibility to create a porous layer out of the bulk material. Activation of the glassy carbon was made either electrochemically or in air at high temperatures.
The probe beam deflection (PBD) technique is based on the deflection of a laser beam, aligned par... more The probe beam deflection (PBD) technique is based on the deflection of a laser beam, aligned parallel to the electrode surface, caused by the concentration profile evolving in front of the electrode during an electrochemical reaction. Monolayer and sub-monolayer sensitivity has been achieved by means of PBD for (i) the proton flux during oxide formation/reduction on a polycrystalline gold electrode and (ii) for the under potential deposition (UPD) of copper on platinum. The potential of the PBD technique for the analysis of electrochemical reactions is demonstrated for the intrinsic redox reaction occurring on activated glassy carbon (GC) electrodes as a consequence of the generation of surface functional groups. PBD clearly reveals that protons are exchanged in acidic electrolyte on activated GC. Finally, the O2 reduction on Au in alkaline electrolytes has been monitored by the probe beam deflection technique.
Chemical science and engineering play a central role in improving the eco-efficiency of energy se... more Chemical science and engineering play a central role in improving the eco-efficiency of energy services, be it by optimizing fossil fuel utilization from the source to the sinks, be it by exploring new ways of replacing fossil fuels with renewable ones. Catalytic fuel processing is required for providing clean and easy to convert inputs from contaminated and/or high molecular weight primary resources into efficient energy conversion systems such as advanced combustion engines and fuel cells. The switch from conventional fossil fuel resources to renewables such as solar or biomass requires new approaches in chemical engineering. Efficiency vs. emissions trade-offs for improving the eco-performance of combustion engines need to be optimized with improved understanding of the complex chemistry taking place in flames. New materials for fuel cells and batteries provide a means of making these devices applicable, thereby drastically cutting down on emissions from energy systems. Chemistry is not only involved in fuel processing and conversion, but it is also important at the end of the pipe, i.e. in catalytic emission control devices, in the treatment of hazardous residues from the incineration of waste materials, and in the complex interactions of air pollutants with the biosphere.
ABSTRACT We studied the effect of counterion type on the ac impedance and linear sweep voltammetr... more ABSTRACT We studied the effect of counterion type on the ac impedance and linear sweep voltammetry response of a film consisting of Os(bpy)2 (bpy indicates 2,2&#39;-bipyridal) coordinatively bound in PVP (poly(4-vinylpyridine)). Four acids were used at 0.1 M in the aqueous bathing electrolytes: hydrochloric, perchloric, trifluoroacetic, and toluenesulfonic. Analysis of the mobile ion concentrations in the film showed that protons were rejected from the film via Donnan exclusion, making anions and hopping electrons the only two charge carriers. Ac impedance spectra revealed that, even with the largest counterion studied, ion transport was much faster than electron hopping. However, the various counterions affected the charge-transport rate indirectly, through modifying the degree of film swelling and the extent of repulsions between electroactive sites. The perchloric acid drastically modified film behavior, presumably through the formation of ion pairs or insoluble salts. Ac impedance spectra also provide evidence of film thickness nonuniformity on the spin-coated electrodes.
... In addition the program can be used to simulate and fit EXAFS spectra using FEFF files for th... more ... In addition the program can be used to simulate and fit EXAFS spectra using FEFF files for the different scattering baths of the outgoing electron. FEFF files were generated with the atomic positions of the perovskites and the FEFF820 code [25]. 3. Results and discussion. 3.1. ...
The ion exchange occurring between a poly(vinylferrocene) (PVF) film and the bathing solution dur... more The ion exchange occurring between a poly(vinylferrocene) (PVF) film and the bathing solution during the oxidation-reduction process was studied by probe beam deflection (PBD) in aqueous and nonaqueous media. In nonaqueous media the results for different electrolyte salts indicate that anions are exchanged. In aqueous media, the ion exchange is strongly affected by the anion present in the solution. In tetrafluoroborate and hexafluorophosphate solutions, cation exchange is observed while in toluenesulfonate solution anion exchange in observed. In perchlorate and trifluoromethanesulfonate solutions a mixed mechanism involving cation and anion exchange is observed. Expulsion of cations precedes anion insertion on oxidation. The ion flux is not affected by the pH (in the range from 1 to 7) or the electrolyte concentration (between 0.1 and 4 M). The kind of ion exchanged appears to correlate with the type of interaction (attractive or repulsive) between redox centers inside the film seen from voltammogram shapes. Ion exchange was also studied during the wetting of the films by electrolyte and shown to be of the same type during the initial cycles of a virgin film in the electrolyte. When a film is left in the reduced state for a period of time, then the next cycle to be recorded reveals a more anodic peak potential and a lower peak current. The ion flux measured by PBD is in the same direction as in continuous cycling.
ABSTRACT 3d metal K-shell X-ray absorption spectra of perovskites with the composition La{sub 1-x... more ABSTRACT 3d metal K-shell X-ray absorption spectra of perovskites with the composition La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} (x=0, 0.2, 0.4, 0.5, 0.6, 0.8), La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) and La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (x=0, 0.2, 0.4, 0.5, 0.6, 0.8) are compared on the basis of pre-edges, white line features and extended fine structures. The measurements were performed at 300 K and for La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} also at temperatures as low as 10-20 K. Going to low-temperature the measurements indicate an increase in t{sub 2g}{sup Low-Asterisk} and a decrease in e{sub g}{sup Low-Asterisk} orbital occupancy, which is most accentuated in the LaCoO{sub 3} sample. Virtually no Co K-edge shift was observed for the La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} compounds and the Co-O distances are also not significantly reduced when La{sup 3+} is partially substituted by Ca{sup 2+} or Sr{sup 2+}. From the pre-edge features of these perovskites we are tended to conclude that the t{sub 2g}{sup Low-Asterisk} orbitals are less, and the e{sub g}{sup Low-Asterisk} orbitals are more occupied with increasing x in the Ca and Sr substituted compounds, whereas the total d-electron density is not changing. These results indicate that cobalt prefers a valence state of 3{sup +} in these Co perovskites. This could also be confirmed with iodometric titrations. The Fe perovskites behave differently. In contrast to the Co perovskites, for La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites the Fe K-edge is shifted, the pre-edge features intensity is increasing and the Fe-O bond length is decreasing with increasing x. The valence states of the iron in the La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites in fact increase as much as x increases. - Graphical abstract: Co K and Fe K pre-edge of La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites one of the evidences in favor of {delta}=x/2 for the Co-perovskites and {delta}=0 for the Fe-perovskites. Highlights: Black-Right-Pointing-Pointer XAS a valuable tool to evaluate the valence states of Co and Fe perovskites. Black-Right-Pointing-Pointer For La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} perovskites {delta} is close to x/2. Black-Right-Pointing-Pointer For La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} series {delta} is close to 0. Black-Right-Pointing-Pointer Discussion of the x dependency of the pre-edge bands.
The thermal oxidation of glassy carbon (GC) was studied in order to explore its potential as a po... more The thermal oxidation of glassy carbon (GC) was studied in order to explore its potential as a porous electrode material for electrochemical double layer capacitors (EDC). Thin GC sheet samples of 55 lm thickness were activated by thermal oxidation to provide an active ®lm with open pores on top of non-activated bulk material with closed pores. Nitrogen gas adsorption, electrochemical impedance spectroscopy and small angle X-ray scattering were applied to characterize the activated GC. The growth of the active ®lm follows a square-root growth law with respect to activation time. It was found that the internal volumetric surface area decreases upon activation, whereas the volumetric electrochemical double layer capacitance increases. It was shown that this eect is correlated with the opening, the growth and the coalescence of the pores. Ó
We studied the incidence of leukemia cutis (LC) in 381 consecutive patients with acute myeloid le... more We studied the incidence of leukemia cutis (LC) in 381 consecutive patients with acute myeloid leu-kemia (AML) in a single institution and compared the demographic, hematological, and cytogenetic findings in AML patients with and without LC. We also examined the response to intensive chemotherapy, overall survival, and duration of remission in this patient population with regard to the presence of LC. The prevalence of LC was 3.7% in clinically diagnosed patients and 2.9% in biopsy proven cases, respectively. Patients with and without LC did not differ with regard to age, sex, white blood cell counts, hemoglobin, fibrinogen, and platelet counts at diagnosis, but lactate dehydrogenase (LDH) was significantly higher in patients with LC. Various karyotype abnormalities were found, but in patients with LC numerical abnormalities of chromosome 8 were significantly more common (P<0.0001). Patients with LC did not differ from patients without LC with regard to remission rate, but there was a trend towards shorter remission duration in patients with LC. We conclude that patients with LC have some features different from patients without this symptom. The increased frequency of numerical aberrations of chromosome 8 in patients with LC was the most interesting observation of our study. The patho-physiological significance of this finding remains to be determined.
A tumour cloning system was used to cultivate breast cancer specimens. Fifty-six percent of 87 sa... more A tumour cloning system was used to cultivate breast cancer specimens. Fifty-six percent of 87 samples were adequate for evaluation, showing clonal growth in about one third (35%). Effusions yielded significantly better growth than solid specimens, the median colony numbers being 64 and 18 respectively. An attempt was made to examine whether there was any association between parameters accepted as prognostic factors for breast cancer and clonal growth in vitro. No correlation was found between preoperative tumour burden, histopathologic grading, menopausal status or overall survival and clonal growth in vitro, whereas we observed an inverse trend between progesterone receptor content of the tumours and their growth potential (P less than 0.01). In those few cases where in vitro and in vivo data could be compared, a high accuracy of the predicted sensitivities was found with respect to chemotherapy, but not in relation to hormonal treatment. A statistically significant higher overall...
An electrochemical double-layer capacitor for high power applications is being developed at the P... more An electrochemical double-layer capacitor for high power applications is being developed at the Paul Scherrer Institute. Glassy carbon was chosen as electrode material because of its inertness, its good bulk conductivity, and the possibility to create a porous layer out of the bulk material. Activation of the glassy carbon was made either electrochemically or in air at high temperatures.
The probe beam deflection (PBD) technique is based on the deflection of a laser beam, aligned par... more The probe beam deflection (PBD) technique is based on the deflection of a laser beam, aligned parallel to the electrode surface, caused by the concentration profile evolving in front of the electrode during an electrochemical reaction. Monolayer and sub-monolayer sensitivity has been achieved by means of PBD for (i) the proton flux during oxide formation/reduction on a polycrystalline gold electrode and (ii) for the under potential deposition (UPD) of copper on platinum. The potential of the PBD technique for the analysis of electrochemical reactions is demonstrated for the intrinsic redox reaction occurring on activated glassy carbon (GC) electrodes as a consequence of the generation of surface functional groups. PBD clearly reveals that protons are exchanged in acidic electrolyte on activated GC. Finally, the O2 reduction on Au in alkaline electrolytes has been monitored by the probe beam deflection technique.
Chemical science and engineering play a central role in improving the eco-efficiency of energy se... more Chemical science and engineering play a central role in improving the eco-efficiency of energy services, be it by optimizing fossil fuel utilization from the source to the sinks, be it by exploring new ways of replacing fossil fuels with renewable ones. Catalytic fuel processing is required for providing clean and easy to convert inputs from contaminated and/or high molecular weight primary resources into efficient energy conversion systems such as advanced combustion engines and fuel cells. The switch from conventional fossil fuel resources to renewables such as solar or biomass requires new approaches in chemical engineering. Efficiency vs. emissions trade-offs for improving the eco-performance of combustion engines need to be optimized with improved understanding of the complex chemistry taking place in flames. New materials for fuel cells and batteries provide a means of making these devices applicable, thereby drastically cutting down on emissions from energy systems. Chemistry is not only involved in fuel processing and conversion, but it is also important at the end of the pipe, i.e. in catalytic emission control devices, in the treatment of hazardous residues from the incineration of waste materials, and in the complex interactions of air pollutants with the biosphere.
ABSTRACT We studied the effect of counterion type on the ac impedance and linear sweep voltammetr... more ABSTRACT We studied the effect of counterion type on the ac impedance and linear sweep voltammetry response of a film consisting of Os(bpy)2 (bpy indicates 2,2&#39;-bipyridal) coordinatively bound in PVP (poly(4-vinylpyridine)). Four acids were used at 0.1 M in the aqueous bathing electrolytes: hydrochloric, perchloric, trifluoroacetic, and toluenesulfonic. Analysis of the mobile ion concentrations in the film showed that protons were rejected from the film via Donnan exclusion, making anions and hopping electrons the only two charge carriers. Ac impedance spectra revealed that, even with the largest counterion studied, ion transport was much faster than electron hopping. However, the various counterions affected the charge-transport rate indirectly, through modifying the degree of film swelling and the extent of repulsions between electroactive sites. The perchloric acid drastically modified film behavior, presumably through the formation of ion pairs or insoluble salts. Ac impedance spectra also provide evidence of film thickness nonuniformity on the spin-coated electrodes.
... In addition the program can be used to simulate and fit EXAFS spectra using FEFF files for th... more ... In addition the program can be used to simulate and fit EXAFS spectra using FEFF files for the different scattering baths of the outgoing electron. FEFF files were generated with the atomic positions of the perovskites and the FEFF820 code [25]. 3. Results and discussion. 3.1. ...
The ion exchange occurring between a poly(vinylferrocene) (PVF) film and the bathing solution dur... more The ion exchange occurring between a poly(vinylferrocene) (PVF) film and the bathing solution during the oxidation-reduction process was studied by probe beam deflection (PBD) in aqueous and nonaqueous media. In nonaqueous media the results for different electrolyte salts indicate that anions are exchanged. In aqueous media, the ion exchange is strongly affected by the anion present in the solution. In tetrafluoroborate and hexafluorophosphate solutions, cation exchange is observed while in toluenesulfonate solution anion exchange in observed. In perchlorate and trifluoromethanesulfonate solutions a mixed mechanism involving cation and anion exchange is observed. Expulsion of cations precedes anion insertion on oxidation. The ion flux is not affected by the pH (in the range from 1 to 7) or the electrolyte concentration (between 0.1 and 4 M). The kind of ion exchanged appears to correlate with the type of interaction (attractive or repulsive) between redox centers inside the film seen from voltammogram shapes. Ion exchange was also studied during the wetting of the films by electrolyte and shown to be of the same type during the initial cycles of a virgin film in the electrolyte. When a film is left in the reduced state for a period of time, then the next cycle to be recorded reveals a more anodic peak potential and a lower peak current. The ion flux measured by PBD is in the same direction as in continuous cycling.
ABSTRACT 3d metal K-shell X-ray absorption spectra of perovskites with the composition La{sub 1-x... more ABSTRACT 3d metal K-shell X-ray absorption spectra of perovskites with the composition La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} (x=0, 0.2, 0.4, 0.5, 0.6, 0.8), La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) and La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (x=0, 0.2, 0.4, 0.5, 0.6, 0.8) are compared on the basis of pre-edges, white line features and extended fine structures. The measurements were performed at 300 K and for La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} also at temperatures as low as 10-20 K. Going to low-temperature the measurements indicate an increase in t{sub 2g}{sup Low-Asterisk} and a decrease in e{sub g}{sup Low-Asterisk} orbital occupancy, which is most accentuated in the LaCoO{sub 3} sample. Virtually no Co K-edge shift was observed for the La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} compounds and the Co-O distances are also not significantly reduced when La{sup 3+} is partially substituted by Ca{sup 2+} or Sr{sup 2+}. From the pre-edge features of these perovskites we are tended to conclude that the t{sub 2g}{sup Low-Asterisk} orbitals are less, and the e{sub g}{sup Low-Asterisk} orbitals are more occupied with increasing x in the Ca and Sr substituted compounds, whereas the total d-electron density is not changing. These results indicate that cobalt prefers a valence state of 3{sup +} in these Co perovskites. This could also be confirmed with iodometric titrations. The Fe perovskites behave differently. In contrast to the Co perovskites, for La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites the Fe K-edge is shifted, the pre-edge features intensity is increasing and the Fe-O bond length is decreasing with increasing x. The valence states of the iron in the La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites in fact increase as much as x increases. - Graphical abstract: Co K and Fe K pre-edge of La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} perovskites one of the evidences in favor of {delta}=x/2 for the Co-perovskites and {delta}=0 for the Fe-perovskites. Highlights: Black-Right-Pointing-Pointer XAS a valuable tool to evaluate the valence states of Co and Fe perovskites. Black-Right-Pointing-Pointer For La{sub 1-x}Ca{sub x}CoO{sub 3-{delta}} and La{sub 1-x}Sr{sub x}CoO{sub 3-{delta}} perovskites {delta} is close to x/2. Black-Right-Pointing-Pointer For La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} series {delta} is close to 0. Black-Right-Pointing-Pointer Discussion of the x dependency of the pre-edge bands.
The thermal oxidation of glassy carbon (GC) was studied in order to explore its potential as a po... more The thermal oxidation of glassy carbon (GC) was studied in order to explore its potential as a porous electrode material for electrochemical double layer capacitors (EDC). Thin GC sheet samples of 55 lm thickness were activated by thermal oxidation to provide an active ®lm with open pores on top of non-activated bulk material with closed pores. Nitrogen gas adsorption, electrochemical impedance spectroscopy and small angle X-ray scattering were applied to characterize the activated GC. The growth of the active ®lm follows a square-root growth law with respect to activation time. It was found that the internal volumetric surface area decreases upon activation, whereas the volumetric electrochemical double layer capacitance increases. It was shown that this eect is correlated with the opening, the growth and the coalescence of the pores. Ó
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