Dynamic Surface Enrichment in Drying Thin-Film Binary Polymer Solutions.

Solution-cast, thin-film polymer composites find a wide range of applications, such as in the photoactive layer of organic solar cells. The performance of this layer crucially relies on its phase-separated morphology. Efficient charge-carrier extraction requires each of the components to preferentially wet one of the two electrodes. It is often presumed that the experimentally observed surface enrichment required for this is caused by specific interactions of the active ingredients with each surface. By applying a generalized diffusion model, we find the dynamics to also play an important role in determining which component accumulates at which surface. We show that for sufficiently fast evaporation the component with the smallest cooperative diffusivity accumulates at the free interface. Counterintuitively, depending on the interactions between the various components, this may be the smaller solute. Our comprehensive numerical and analytical study provides a tool to predict and control phase-separated morphologies in thin-film polymer composites.

Elimination of charge carrier trapping in diluted semiconductors.

In 1962, Mark and Helfrich demonstrated that the current in a semiconductor containing traps is reduced by N/Nt(r), with N the amount of transport sites, Nt the amount of traps and r a number that depends on the trap energy distribution. For r > 1, the possibility opens that trapping effects can be nearly eliminated when N and Nt are simultaneously reduced. Solution-processed conjugated polymers are an excellent model system to test this hypothesis, because they can be easily diluted by blending them with a high-bandgap semiconductor. We demonstrate that in conjugated polymer blends with 10% active semiconductor and 90% high-bandgap host, the typical strong electron trapping can be effectively eliminated. As a result we were able to fabricate polymer light-emitting diodes with balanced electron and hole transport and reduced non-radiative trap-assisted recombination, leading to a doubling of their efficiency at nearly ten times lower material costs.

Diffuse Lipomatosis of the Thyroid Gland: Report of Two Cases and Review of The Literature of a Curious Entity

Aim: Study of the incidence of diffuse lipomatous infiltration of the thyroid gland. Patients and methods: 320 cases of thyroid pathology representing one year of activity of the pathology department; were reviewed by the authors. Results: We observed 2 cases of lipomatous infiltration of the thyroid gland; the princeps case showed mature adipose tissue scattered between the thyroid follicles; occupying approximately 40% of the thyroid gland; and only one other case upon review of the 320 thyroid glands registered in our pathology department this year; with about 5 to 10% of adipose tissue. We found randomly distributed adipocytes in subcapsular location in 59 cases (18.5%); with 24 cases (7.5 %) with more than 1% and 35 cases (11%) with less than 1% of adipocytes. We noticed also the presence of one adenolipoma

Structuring of polymer solutions upon solvent evaporation.

The morphology of solution-cast, phase-separated polymers becomes finer with increasing solvent evaporation rate. We address this observation theoretically for a model polymer where demixing is induced by steady solvent evaporation. In contrast to what is the case for a classical, thermal quench involving immiscible blends, the spinodal instability initially develops slowly and the associated length scale is not time invariant but decreases with time as t(-1/2). After a time lag, phase separation accelerates. Time lag and characteristic length exhibit power-law behavior as a function of the evaporation rate with exponents of -2/3 and -1/6. Interestingly, at later stages the spinodal structure disappears completely while a second length scale develops. The associated structure coarsens but does not follow the usual Lifshitz-Slyozov-Wagner kinetics.

Molecular depth profiling of organic photovoltaic heterojunction layers by ToF-SIMS: comparative evaluation of three sputtering beams.

With the recent developments in secondary ion mass spectrometry (SIMS), it is now possible to obtain molecular depth profiles and 3D molecular images of organic thin films, i.e. SIMS depth profiles where the molecular information of the mass spectrum is retained through the sputtering of the sample. Several approaches have been proposed for "damageless" profiling, including the sputtering with SF5(+) and C60(+) clusters, low energy Cs(+) ions and, more recently, large noble gas clusters (Ar500-5000(+)). In this article, we evaluate the merits of these different approaches for the in depth analysis of organic photovoltaic heterojunctions involving poly(3-hexylthiophene) (P3HT) as the electron donor and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as the acceptor. It is demonstrated that the use of 30 keV C60(3+) and 500 eV Cs(+) (500 eV per atom) leads to strong artifacts for layers in which the fullerene derivative PCBM is involved, related to crosslinking and topography development. In comparison, the profiles obtained using 10 keV Ar1700(+) (∼6 eV per atom) do not indicate any sign of artifacts and reveal fine compositional details in the blends. However, increasing the energy of the Ar cluster beam beyond that value leads to irreversible damage and failure of the molecular depth profiling. The profile qualities, apparent interface widths and sputtering yields are analyzed in detail. On the grounds of these experiments and recent molecular dynamics simulations, the discussion addresses the issues of damage and crater formation induced by the sputtering and the analysis ions in such radiation-sensitive materials, and their effects on the profile quality and the depth resolution. Solutions are proposed to optimize the depth resolution using either large Ar clusters or low energy cesium projectiles for sputtering and/or analysis.

Effect of adjuvant chemotherapy on survival in FNCLCC grade 3 soft tissue sarcomas: a multivariate analysis of the French Sarcoma Group Database.

BACKGROUND: The predictive value of grade for benefit from adjuvant chemotherapy (AC) in soft tissue sarcoma (STS) patients has never been explored. PATIENTS AND METHODS: From 1980 to 1999, 1513 adult patients with non-metastatic STS were included prospectively in the French Sarcoma Group database. Grade was assessed according to the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) system after central review. RESULTS: AC was delivered to 13 grade 1 patients (3%), 145 grade 2 patients (35%) and 262 grade 3 patients (62%). Young age, non-well-differentiated liposarcoma histology, deep location, bone and/or neurovascular invasion and grade 2 or 3 were significantly associated with a higher likelihood to receive AC. Median follow-up was 9 years. On multivariate analysis, AC was significantly associated with improved metastasis-free survival (MFS) [5-year MFS: 58% versus 49%, hazard ratio (HR) 0.7 (95% confidence interval (CI) 0.6-0.9), P = 0.01] and overall survival (OS) [5-year OS: 58% versus 45%, HR 0.6 (95% CI 0.5-0.8), P = 0.0002] in grade 3 patients. This was not observed in grade 2 patients [5-year MFS: 76% versus 73%, HR 0.8 (95% CI 0.5-1.2), P = 0.27; 5-year OS: 75% versus 65%, HR 0.8 (95% CI 0.6-1.1), P = 0.15]. CONCLUSION: This large cohort-based analysis with long-term follow-up indicates that patients with FNCLCC grade 3 disease may benefit from AC.

Soft tissue sarcomas of the trunk wall (STS-TW): a study of 343 patients from the French Sarcoma Group (FSG) database.

BACKGROUND: Soft tissue sarcomas of the trunk wall (STS-TW) are usually studied together with soft tissue sarcomas of other locations. We report a study on STS-TW forming part of the French Sarcoma Group database. PATIENTS AND METHODS: Three hundred and forty-three adults were included. We carried out univariate and multivariate analysis for overall survival (OS), metastasis-free survival (MFS) and local recurrence-free survival (LRFS). RESULTS: Tumor locations were as follows: thoracic wall, 82.5%; abdominal wall, 12.3% and pelvic wall, 5.2%. Median tumor size was 6.0 cm. The most frequent tumor types were unclassified sarcoma (27.7%) and myogenic sarcoma (19.2%). A total of 44.6% of cases were grade 3. In all, 21.9% of patients had a previous medical history of radiotherapy (PHR). Median follow-up was 7.6 years. The 5-year OS, MFS and LRFS rates were 60.4%, 68.9% and 58.4%, respectively. Multivariate analysis retained PHR and grade for predicting LRFS and PHR, size and grade as prognostic factors of MFS. Factors influencing OS were age, size, PHR, depth, grade and surgical margins. The predictive factors of incomplete response were PHR, size and T3. CONCLUSIONS: Our results suggest similar classical prognostic factors as compared with sarcomas of other locations. However, a separate analysis of STS-TW revealed a significant poor prognosis subgroup of patients with PHR.

[Vacuum-assisted stereotactic biopsy: experience of the regional cancer center of Caen]. / Macrobiopsies assistées par le vide: expérience du CRLCC François Baclesse de Caen.

PURPOSE: To report our experience with macrobiopsy under stereotaxy. MATERIALS AND METHODS: Retrospective study of 248 procedures in 236 patients for microcalcifications in 95% of cases. The macrobiopsies were performed under Mammotome for lesions graded ACR 3, ACR 4 and ACR 5 in 8.4%, 81.6% and 14.8% of cases respectively. RESULTS: From a technical point of view, 91% of procedures had no technical problem. The image guided excision was complete in 68% of cases with lesions less than 1 cm in size and in 6% of cases for lesions larger than 1 cm. The rate of a misdiagnosis of ductal carcinoma in situ for patients with invasive carcinoma was 27% whereas the rate of a misdiagnosis of atypical ductal hyperplasia in patients with ductal carcinoma in situ was 25% knowing that patients with atypical ductal hyperplasia for which all microcalcifications had been fully removed by macrobiopsy and without risk factors did not undergo surgery. CONCLUSION: Even if macrobiopsy of microcalcifications is a reliable method, its main limitation remains the risk of misdiagnosis of borderline lesions.

Immunohistochemical study of cell cycle regulatory proteins in intraductal breast carcinomas--a preliminary study.

The aim of this study was to assess the levels of cell cycle regulatory proteins p21waf1 (p21), p53, Cyclin A, Cyclin D1 and Ki-67 to see whether they correlated with recurrence-free survival (RFS). From 1982 to 1996, 50 patients aged less than 51 years underwent lumpectomy followed by radiotherapy for a pure ductal carcinoma in situ (DCIS). For each case, the following immunohistochemical stains were carried out: Ki-67, Cyclin A, Cyclin D1, p53 and p21waf1 (p21). The percentage of positive nuclei was assessed. Multiple combinations of these factors were performed; in particular, we called the sum of Ki-67 and Cyclin A a global proliferation factor (GPF). Correlations with classical clinicopathological data were assessed. After a multivariate analysis, only GPF, Van Nuys Prognostic Index (VNPI) grade and mitotic index were independent predictive factors of recurrence in the whole population. In the population with close surgical margins, when the GPF level was less than the 25th percentile or more than the 75th percentile recurrence was low. In this preliminary study, GPF seems to be of interest to help in the decision process in the post-surgical management of the patient.

Double immunohistochemical labeling technique applied to different types of cytokeratins in epithelial proliferations of the breast.

The double labeling technique using peroxidase and alkaline phosphatase for immunohistochemistry is well known, but must be adapted according to the antibodies used, fixation, and technical conditions. The technique allows identification on one slide of two antigens that are localized in the same or different cells of the same lesion. The aim of this paper is to describe the adaptation of this technique to cytokeratins of normal mammary tissue and proliferative lesions of the breast.

Reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials.

Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

Improved measurement of formaldehyde in water-soluble polymers by high-performance liquid chromatography coupled with post-column reaction detection.

An improved methodology for the analysis of free formaldehyde in water-soluble polymers used for industrial water treatment is reported. Previously, derivatization prior to HPLC or colorimetric techniques has been used. The data generated by these approaches are suspect in that the derivatizing agent can react with the polymer or other sample components to produce high results. Post-column reaction derivatization is applied after separation of the free formaldehyde from the product interferences. The type of polymer product analyzed influences the choice of column(s). The degree of high bias of the commonly used 2,4-dinitrophenylhydrazine pre-column derivatization is reported and the results are compared to those with the post-column reaction for two polymer products. This method, being more selective, should be applicable to any polymer containing formaldehyde.

Flow cytometry in primary breast carcinomas. Prognostic impact of proliferative activity.

From 1990 to 1996, 607 previously untreated, node-negative, invasive breast carcinomas were sampled by a pathologist for flow-cytometric DNA analysis. The aim of the present work was to study the correlations between flow cytometric results obtained thanks to the American Consensus (AC) guidelines of 1993 and the established clinico-pathological prognostic factors (T, grade, receptors), and despite a short global follow-up (mean of 4 years), to correlate flow cytometry with the outcome of the patients. In this study S-phase fraction (SPF) correlated strongly with tumor size, histological grade, lack of steroid receptors, histological type and was together with the mitotic activity a paramount prognostic factor even after multivariate analysis. This study compared also the technical criteria proposed by the AC with our own more stringent ones and concluded that the criteria of the AC are relevant and allow, thanks to the use of tertiles in the reporting of SPF values, a comparison of values obtained by different teams. Our review of the literature, focused on series using fresh material, enabled us to show that there is a rather wide agreement concerning the relationship between SPF and prognosis most often after multivariate analysis. This despite the lack of standardization in the design of the studies (implementation of the technical steps or reporting of results). When estimated from fresh or frozen material following AC's guidelines. SPF along with mitotic activity should become a prognostic factor used in the daily practice by oncologists in the management of breast carcinomas.

[Atypical prostatic leiomyoma: a new case with cytodensitometric analysis]. / Léiomyome à cellules bizarres de la prostate: un nouveau cas avec étude cytométrique.

Atypical prostatic leiomyoma is a very rare benign tumor. We report here a new case with a cytodensitometric analysis. The result of cytodensitometry is a polyploid tumor that is well correlated with the morphology of nuclear multilobulated cells of this tumor. The differential diagnosis is essentially the leiomyosarcoma which is characterized by the absence of mitotic activity.

Variation of flow cytometric DNA measurement in 1,485 primary breast carcinomas according to guidelines for DNA histogram interpretation.

From 1990-1996, 1,485 previously untreated invasive breast carcinomas were sampled by a pathologist for flow cytometric DNA analysis. The aim of the present work was to study the variations of flow cytometric DNA ploidy and S-phase evaluation according to the conditions of DNA histogram interpretation. Results obtained with the American Consensus guidelines of 1993 and the François Baclesse Department of Pathology's own guidelines are presented. According to the percentage of events taken into account to identify a DNA aneuploid peak, the proportion of DNA diploid cases can change from 35-39%. For S-phase evaluation, although the two guidelines were quite different, the results of S-phase cutoff were identical. Whichever guidelines were used, there was a strong relationship between DNA ploidy and/or S-phase and classical clinicopathological factors (T, N, histological type, grade, receptor status, or lymphatic invasion), with the exception of age, whose correlation was discrepant with S phase according to the set of guidelines. Whichever guidelines were used, ploidy and S phase correlated strongly with survival (overall, metastasis-free, or recurrence-free). Hence we recommend the use of the American consensus guidelines, despite minor imperfections, because they are now well-known, allow a high yield in the ratio of assessable S phases, and permit standardization in the technical processing and reporting of S phases, thanks to the use of terciles.

Degradation pathway of homoserine lactone bacterial signal molecules by halogen antimicrobials identified by liquid chromatography with photodiode array and mass spectrometric detection.

The degradation pathway of acylated homoserine lactone bacterial signaling molecules by oxidizing hypochlorite and stabilized hypobromite antimicrobials has been characterized. A reversed-phase HPLC separation using a cyano column was developed to detect the parent lactones, lactone-hydrolysis products, and halogenation products. Elucidation of the structures of the reaction products was done with the aid of online photodiode array UV spectroscopy and atmospheric pressure chemical ionization mass spectrometry. Quantitative output of the HPLC method was also used to estimate the kinetics of the degradation pathway. The results of this work found that only beta-keto-amide signal molecules are halogenated, where normal amide signals are not, and may represent one possible mechanism for control of industrial biofilms.

[Flow cytometry in ORL cancers]. / Cytométrie en flux dans les cancers ORL.

The possibility to perform flow cytometry was examined in a series of 167 patients with primary untreated head and neck carcinoma referred to our Institution from February 1989 to January 1992. In all cases, flow cytometry was carried out on frozen tumour samples. The Cox model was used including age, tumour size, nodal status on clinical assessment, topography, treatment, malignancy grade, S phase fraction and ploidy as independent variables and overall survival as dependent variable. In this study, ploidy could be assessed in only 73% of cases and S phase fraction and G2M in 65% of the population studied. No correlation could be evidenced between ploidy or SPF with other clinical, pathologic characteristics or clinical outcome. We conclude that flow cytometry should remain a research tool until the method has proved to be relevant in clinical routine, and until the yield of the technique can be improved.

[Neuroblastoma arising in testicular teratoma]. / Neuroblastome survenant dans un tératome testiculaire.

One case of neuroblastoma arising in an adult immature testicular teratoma is described, with multiple systemic metastases, a partial response to intensive chemotherapy and a swift recurrence leading to death. Such instances of prevailing neuroblastoma with systemic metastases, have only seldomly been reported hitherto. Because of the teratoma and the focal presence of intratubular germ cell neoplasia of unclassified type, we think this tumor must be indeed of germ cell derivation.

[Extemporaneous histologic examination of cutaneous carcinoma of the face]. / Examen histologique extemporané dans les carcinomes cutanés de la face.

One hundred thirty-eight skin cancers of the face were reviewed retrospectively in order to evaluate the extemporaneous histology examination. The results obtained were satisfactory and in agreement with those in the literature. This technique is perfectly adapted to cancers with a facial localization. In our opinion, the indication for extemporaneous examinations should be widened to all cases of epithelioma of the face.