Bond-Breaking Efficiency of High-Energy Ions in Ultrathin Polymer Films.

Thin films of poly(methyl methacrylate) and poly(vinyl chloride) of different thickness are used to investigate the effect of spatial confinement on the efficiency of bond breaking induced by 2 MeV H^{+} and 2.1 GeV Bi ions. Effective cross sections for oxygen and chlorine loss are extracted for films down to a thickness of about 5 nm and are compared to theoretical estimations based on radial energy density profiles simulated with geant-dna. The cross sections are to a large extent thickness independent, indicating that bond breaking is dominated by short-range processes. This is in contrast to the strongly reduced efficiencies found recently for cratering induced by high-energy ions in similar ultrathin polymer films [Phys. Rev. Lett. 114, 118302 (2015)PRLTAO0031-900710.1103/PhysRevLett.114.118302].

Confinement effects of ion tracks in ultrathin polymer films.

We show direct experimental evidence that radiation effects produced by single MeV heavy ions on a polymer surface are weakened when the length of the ion track in the material is confined into layers of a few tens of nanometers. Deviation from the bulk (thick film) behavior of ion-induced craters starts at a critical thickness as large as ∼40 nm, due to suppression of long-range additive effects of excited atoms along the track. Good agreement was found between the experimental results, molecular dynamic simulations, and an analytical model.

Direct evidence for projectile charge-state dependent crater formation due to fast ions.

We report on craters formed by individual 3 MeV/u Au (q(ini)+) ions of selected incident charge states q_(ini) penetrating thin layers of poly(methyl methacrylate). Holes and raised regions are formed around the region of the impact, with sizes that depend strongly and differently on q_(ini). Variation of q_(ini) of the film thickness and of the angle of incidence allows us to extract information about the depth of origin contributing to different crater features.

Magnetic force microscopy of nano-size magnetic domain ordering in heavy ion irradiated fullerene films.

In the present work, magnetic force microscopy is employed to investigate the magnetic ordering in ion irradiated fullerene films. It is observed that magnetic domain size is approximately 100-200 nm and magnetic signal is stronger at the domain boundaries. Magnetic signal arise in irradiated films is confirmed by magnetic measurements using a superconducting quantum interference device which increases with the ion fluence. The induced magnetism is possibly due to structural defects in the amorphous carbon phase formed by ion irradiation.

Ion crater healing and variable temperature ellipsometry as complementary probes for the glass transition in thin polymer films.

Poly(methyl methacrylate) (PMMA) thin films of various tacticity and thickness were bombarded at grazing angles by 20 MeV Au ions at different temperatures. The shape of the tracks was investigated by scanning force microscopy (SFM) after annealing for various time at different temperatures and constant quenching rate. The thickness dependent glass transition temperature, T(g)(h), was estimated from the temperature of relaxation of ion-caused nanodeformations in the films. T(g)(h) obtained from the thermal healing of the holes and hillocks is found in good agreement with the one determined by variable temperature ellipsometry for PMMA film thickness of 80 nm and corresponds to the T(g) of each bulk PMMA stereoisomer. Below this thickness, some significant divergences are observed between the T(g) measured by the two techniques. We propose that the healing of ion crater hillock and the kink in the thermal expansion arise from the different nature of chains motions which are perturbed to different extents according to the main polymer chain preferential orientation in the thin film. This can be tentatively interpreted by a so-called "anisotropic" character of the glass transition.

Left ventricular free wall rupture during coronary intervention after acute myocardial infarction: report of two cases exhibiting fatal pseudocomplications.

Two cases of left ventricular free wall rupture occurring in temporal relation to interventional coronary procedures are presented as autopsy-verified pseudocomplications. The possible impact of pseudocomplications on operator-specific registry data and credentialing is briefly discussed.

External quality assurance in cervical/vaginal cytology: Interlaboratory agreement in the Emilia-Romagna region of Italy.

OBJECTIVE: To evaluate the diagnostic agreement between seven cervical/vaginal cytology laboratories participating in the first external quality assurance (EQA) scheme developed in Italy. STUDY DESIGN: Between 1991 and 1993, 110 cytologic smears were selected and classified by a committee and circulated and reported on by the laboratories according to the 1988 Bethesda System. Agreement was evaluated with the kappa statistic. Systematic disagreement was assessed by means of the Wilcoxon signed rank test. RESULTS: Interlaboratory kappa values varied between .01 and .29 (group score, .11) for sample adequacy and between .53 and .78 (group score, .67) for epithelial abnormalities. The lowest specific kappa values were observed for the three classes of sample adequacy (unsatisfactory, .07; less than optimal [LTO], .10; satisfactory [SAT], .14) and for the class of atypical cells of undetermined significance (ACUS), (.29). As compared with the study committee, 5/7 laboratories showed a systematic (P<.01) tendency to undercall sample adequacy. Agreement on epithelial abnormalities was also analyzed according to the pattern of adequacy reported by paired laboratories (LTO/LTO, LTO/SAT, SAT/SAT). As compared with smears designated SAT/SAT, those classified as LTO/SAT were associated with lower specific kappa values for agreement on the presence of carcinoma and ACUS and with equal or greater values for agreement on the other classes, suggesting an arbitrary use of notations of LTO inversely related to the severity of epithelial lesions. CONCLUSION: EQA schemes, as applied to cervical/vaginal cytology, can shed light on major deficiencies in specific diagnostic areas.

[A cytofluorimetric analysis of the DNA content and S phase in intraepithelial neoplasia of the cervix uteri]. / Analisi citofluorimetrica del contenuto in DNA e fase S nelle neoplasie intraepiteliali della cervice uterina.

The natural history of cervical intraepithelial neoplasia (CIN) evidenced in such pathologies a different biological behaviour due to the presence of similar morphological atypia with different potential development. To biologically characterize CIN lesions we valued by flow cytometry, the DNA content and the proliferative activity of 53 biopsies obtained by colposcopy. Aneuploid histograms were present in none of the histologically negative lesions, in 14% of the CIN I, in none CIN II, and in 40% of the CIN III. The mean value of S-phase was 2.7% in non dysplastic lesions, 5% in the CIN I, 2.5% in the CIN II and 6.1% in the CIN III. In this study the findings of aneuploid cells and the value of proliferative activities seems to be not correlated with the histological features. The clinical and instrumental follow up of the considered patients could establish the eventual prognostic significance of cytofluorimetric parameters in CIN lesions.

[Role of colposcopy in high-grade CIN (CIN II-III)]. / Il ruolo della colposcopia nelle CIN di grado elevato (CIN II-III).

We have considered the colpo-cytologic characteristic of 83 patients with CIN II-III histologic lesions over 900 colposcopic biopsies carried out at our Department from 1990-1992. In particular 38 cases were classified as CIN II of which 23 associated with HPV cytopathic feature, while 45 cases were, classified as CIN III, of which 13 associated with HPV c.f. 29% of CIN II were evident in women under 30 years of age; in this group the age decreased with the presence of HPV. 31% of CIN III were present in women under 35. A good correlation between cytologic and histological analysis on the same patient was observed particularly in CIN with the higher grade. Also a good correlation between colposcopy grading and CIN was observed. In CIN II, grade I images were present, while in CIN III, punctuation and white epithelium were the most common features. Our study shows also the impossibility of distinguishing between the images of simple viral infection and their related CIN morphologic patterns. Colposcopy represents a basic test for the definition of CIN, particularly for those with higher grade, and a complementary test for the definition of the topography of the lesions with the correct choice of the therapeutic treatment.

[The role of colposcopy in the diagnosis of HPV infection]. / Il ruolo della colposcopia nella diagnosi dell'infezione virale da HPV.

Human papillomavirus (HPV) has been implicated as an important etiologic factor in cervical carcinoma. This study evaluates the efficacy of colposcopy in the detection of cervical lesions with koilocytosis features. Colposcopy, cervical smears and biopsy specimens from 217 women seen in our department between January-December 1991 were examined. The colposcopy examination detected 77.5% of the viral presence the histological diagnosis detected 85% of HPV, but the cytologic smears showed only 52% of infection. The data suggests that colposcopy is a good examination to evidence koilocytosis infection.

[Cervico-vaginal screening in some Local Sanitary Units of the Emilia-Romagna region]. / Lo screening cervico-vaginale in alcune USL della Regione Emilia-Romagna.

Some Local Sanitary Units (USL) of the Emilia-Romagna region were contacted to define cervical screening variables, such as adequacy of smear technique, data collection and evaluation, laboratory quality control modalities of invitations to screening. Our data show there are a lot of deficiencies in the present management of the cervical program in Romagna. The most serious inadequacies concern data evaluation, follow-up, cytologic quality control, modalities of active invitations of women to screening. The survey has confirmed the need for launching organized programs of cervical screening to promote their efficacy of diagnosis and therapy.