High-resolution investigations of ripple structures formed by femtosecond laser irradiation of silicon

We report on the structural investigation of self-organized periodic microstructures (ripples) generated in Si(100) targets after multishot irradiation by approximately 100-fs to 800-nm laser pulses at intensities near the single shot ablation threshold. Inspection by surface sensitive microscopy, e.g., atomic force microscopy (AFM) or scanning electron microscopy (SEM), and conventional and high-resolution transmission electron microscopy reveal complex structural modifications upon interaction with the laser: even well outside the ablated area, the target surface exhibits fine ripple-like undulations, consisting of alternating crystalline and amorphous silicon. Inside the heavily modified area, amorphous silicon is found only in the valleys but not on the crests which, instead, consist of highly distorted crystalline phases, rich in defects

Role of THBS1, WHSC1, ADAMTS1 and RBFOX2 genes in the radiation-induced Dna double strand break repair in Hela tumor cell line

It is well known that inter-individual differences of radiosensitivity have genetic causes, such as variations in the level of DNA or expression of DNA repair genes. However, differentially expressed genes which could lead to inter-individual differences in the level of DNA damage remain largely unidentified. In our study we have induced knock-out of THBS1, WHSC1, ADAMTS1 and RBFOX2 genes in HeLa cell line to clarify the effects of these genes on DNA repair and radiosensitivity

On the electronic properties of a single dislocation

A detailed knowledge of the electronic properties of individual dislocations is necessary for next generation nanodevices. Dislocations are fundamental crystal defects controlling the growth of different nanostructures (nanowires) or appear during device processing. We present a method to record electric properties of single dislocations in thin silicon layers. Results of measurements on single screw dislocations are shown for the first time. Assuming a cross-section area of the dislocation core of about 1 nm2, the current density through a single dislocation is J = 3.8 × 1012 A/cm2 corresponding to a resistivity of ρ ≅ 1 × 10-8 Ω cm. This is about eight orders of magnitude lower than the surrounding silicon matrix. The reason of the supermetallic behavior is the high strain in the cores of the dissociated dislocations modifying the local band structure resulting in high conductive carrier channels along defect cores

Disassembly and sampling of graphite ball fuel elements

In the scope of the THTR postirradiation examination program, irradiated ball-type fuel elements must be examined and prepared for advanced experiments. This requires a controlled breaking-open of the graphite shell for taking samples of definite size and dimensions from the inner and outer parts of the fuel element. In the present report are described two special pieces of equipment which have been developed and constructed for this purpose. They emphasize avoiding contaminationof the neighbouring equipment of the box, and diminishing the inevitable cross-contamination of the surfaces of the samples themselves by means of a suitableventilation procedure

Predicting Drusen Regression from OCT in Patients with Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries. The presence of drusen is the hallmark of early/intermediate AMD, and their sudden regression is strongly associated with the onset of late AMD. In this work we propose a predictive model of drusen regression using optical coherence tomography (OCT) based features. First, a series of automated image analysis steps are applied to segment and characterize individual drusen and their development. Second, from a set of quantitative features, a random forest classifiser is employed to predict the occurrence of individual drusen regression within the following 12 months. The predictive model is trained and evaluated on a longitudinal OCT dataset of 44 eyes from 26 patients using leave-one-patient-out cross-validation. The model achieved an area under the ROC curve of 0.81, with a sensitivity of 0.74 and a specificity of 0.73. The presence of hyperreflective foci and mean drusen signal intensity were found to be the two most important features for the prediction. This preliminary study shows that predicting drusen regression is feasible and is a promising step toward identification of imaging biomarkers of incoming regression

Mixed states: Still a modern psychopathological syndrome?

The aim of this review is to evaluate whether the DSM-5 concept of mixed features \u201cspecifier\u201d provides a definition that reflects the richness and multiplicity of this psychopathological picture pointing out the historical development, clinical concepualisation and proposed therapeutic approach to mixed states. We review and discuss the recent evidence on the presence of mixed features during mania and depression and summarise findings on the conceptualisation of mixed states. Electronic searches of all English-language papers were performed in the MEDLINE and PUBMED database using and cross-listing key words: mixed state, mixed features, bipolar disorder, major depressive disorder, mania, hypomania, depression. The mixed categorical-dimensional concept used in the DSM- 5 broadens the concept of mixed episodes, introducing substantial changes to the diagnosis of mixed states. This definition appears more appropriate for less severe forms of mixed states presenting clear and detectable mood symptoms with evident improvement compared to the DSM-IV, as the possibility of classifying depression \u201cwith mixed features\u201d. The transition from the classical definition of mixed states to the one reported in the DSM-5 has determined a complex modification of the concept of mixed state. The DSM-IV-TR description, based on the co-presence of symptoms of opposite polarity, was extremely reductive and did not capture the sub-syndromal symptoms of the opposite pole experienced in bipolar and major depressive disorders. The DSM-5 definition of mixed features \u201cspecifier\u201d represents a valid tool to improve the recognition and proper treatment of bipolar mixed patients, reducing misdiagnosis and mistreatment associated with chronic and repetitive exposure to antidepressants and sedatives, although the mixed categorical-dimensional concept does not adequately reflect some overlapping mood criteria, such as mood lability, irritability and psychomotor agitation

Feasibility of Photofrin II as a radiosensitizing agent in solid tumors - Preliminary results

Background: Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in in vitro and in vivo tumor models. We aimed to investigate the feasibility of a clinical application of Photofrin II. Material and Methods: 12 patients were included in the study (7 unresectable solid tumors of the pelvic region, 3 malignant gliomas, 1 recurrent oropharyngeal cancer, 1 recurrent adenocarcinoma of the sphenoid sinus). The dose of ionizing irradiation was 30-50.4 Gy; a boost irradiation of 14 Gy was added for the pelvic region. All patients were intravenously injected with 1 mg/kg Photofrin II 24 h prior to the commencement of radiotherapy. Magnetic resonance imaging (MRI) controls and in some cases positron emission tomography (PET) were performed in short intervals. The mean follow-up was 12.9 months. Results: No major adverse events were noted. Minor adverse events consisted of mild diarrhea, nausea and skin reactions. A complete remission was observed in 4/12 patients. A reduction in local tumor volume of > 45% was achieved in 4/12 patients. Stable disease was observed in 4/12 patients. 1 patient showed local disease progression after 5 months. Conclusion: The early follow-up results are encouraging regarding the feasibility of the application of Photofrin II as a radiosensitizing agent

Stable registration of pathological 3D-OCT scans using retinal vessels

We propose a multiple scanner vendor registration method for pathological retinal 3D spectral domain optical coherence tomography volumes based on Myronenko’s Coherent Point Drift and our automated vessel shadow segmentation. Coherent point drift is applied to the segmented retinal vessel point sets used as landmarks to generate the registration parameters required. In contrast to other registration methods, our solution incorporates a landmark detection and extraction method that specifically limits the extraction of false positives and a registration method capable of handling any such noise in the landmark point sets. Our experiments show modified Hausdorff distance is reduced by a minimum of 91% between target and registered vessel point sets with at least 94% of bifurcations correctly overlapping based on ground truth, a significant improvement over current methods