Blue Ink Research Articles

2030 PHANTOM STUDY OF A NOVEL STEREOTACTIC PROSTATE BIOPSY SYSTEM INTEGRATING PREINTERVENTIONAL MRI AND LIVE US FUSION

You have accessJournal of UrologyImaging/Radiology: Uroradiology I1 Apr 20122030 PHANTOM STUDY OF A NOVEL STEREOTACTIC PROSTATE BIOPSY SYSTEM INTEGRATING PREINTERVENTIONAL MRI AND LIVE US FUSION Timur Kuru, Matthias Roethke, Dogu Teber, Boris Hadaschik, and Markus Hohenfellner Timur KuruTimur Kuru Heidelberg, Germany More articles by this author , Matthias RoethkeMatthias Roethke Heidelberg, Germany More articles by this author , Dogu TeberDogu Teber Heidelberg, Germany More articles by this author , Boris HadaschikBoris Hadaschik Heidelberg, Germany More articles by this author , and Markus HohenfellnerMarkus Hohenfellner Heidelberg, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2194AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES To determine the targeting error of a novel stereotactic prostate biopsy system, which integrates preinterventional MRI with periinterventional ultrasound for perineal navigated prostate biopsies. METHODS We performed stereotactic biopsies on 5 prostate phantoms (one CIRS 053-MM and four CIRS 066). Phantom 053-MM incorporates three MRI- and TRUS-visible lesions, while lesions within phantom 066 are only detectable on MRI. In both phantoms the 0.5cc volume lesions are randomly placed. The phantoms were examined by 3T-MRI preinterventionally. Then 3 stereotactic biopsies from one lesion in phantom 053-MM and from all ultrasound-invisible lesions in the 066 phantoms were taken under live-fusion-imaging guidance. During intervention a mix of blue ink and gadobutrol was injected into each biopsy channel. Afterwards 3T-MRI was obtained again. These MRI images were then fused again with the intraoperative TRUS-data. Thus, the targeting error (TE) between the planned and performed biopsy cores could be measured. Additionally, the procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered three-dimensional needle position of every single biopsy core taken was calculated. RESULTS The overall targeting error (TE) of the 39 biopsy-cores taken was 0.83mm (SD: 0.48mm) with the highest TE in the sagittal plane (1.09±0.54mm), followed by the coronal (0.72±0.43mm) and axial (0.69±0.34mm) planes. The procedural targeting error, which is provided intraoperatively, was 0.26mm in average (SD: 0.46mm). Comparing PTE and TE, there was no statistically significant difference (p=0.39). CONCLUSIONS The targeting error of stereotactic biopsies using our novel perineal prostate biopsy system (BiopSee®, MedCom, Germany) is below 1mm and can be estimated in vivo by the automatically calculated procedural targeting error. Stereotactic prostate biopsies guided by the combination of MRI and ultrasound allow effective and precise examination of MRI-lesions. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e819 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Timur Kuru Heidelberg, Germany More articles by this author Matthias Roethke Heidelberg, Germany More articles by this author Dogu Teber Heidelberg, Germany More articles by this author Boris Hadaschik Heidelberg, Germany More articles by this author Markus Hohenfellner Heidelberg, Germany More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Classification of blue pen ink using infrared spectroscopy and linear discriminant analysis

Attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy associated to linear discriminant analysis (LDA) was employed to perform classification of blue pen ink according to types and brands, in a nondestructive way. To build a representative data set, blue pens of 3 types, namely ballpoint (5 brands), roller ball (2 brands) and gel (3 brands) were purchased from local dealers. Ten different pens, representing the best seller of each brand, were purchased, making a total of 100 pens. Circular areas were painted five times with each pen and spectra were taken in 2 different locations, using a Universal Attenuated Total Reflectance accessory (UATR), within the range of 4000 to 650cm−1. Three types of paper were employed: two brands of A4 sulfite paper (paper 1 and paper 2) and one recycled paper (paper 3). The genetic algorithm (GA), stepwise formulation (SW) and successive projections algorithm (SPA) were employed to select spectral variables employed in LDA. LDA models were built using the blue pen ink spectra obtained from paper 1. Three test sets were employed using the blue pen ink spectra obtained from papers 1, 2 and 3, in order to evaluate the influence of the paper on the predictions. The LDA models used to classify the pens according to their type (gel, rollerball and ballpoint) achieved a correct classification rate of 100% in the test set composed of blue pen ink spectra obtained from paper 1, using GA and SPA. Using SW, the rate achieved was 99.5%. For paper 2, SPA, GA and SW provided 100%, 97.3% and 93.8% of correct classification, respectively. For paper 3, SPA, GA and SW achieved a correct prediction rate of 100%, 100% and 94.9%, respectively. LDA models for classifications of pens according to their brand were 100% correct in their classification when the test set was composed of blue pen ink spectra obtained from papers 1 and 2. For the test set composed of blue pen ink spectra obtained from paper 3, LDA-SPA, LDA-GA and LDA-SW classified them correctly at 91.3%, 100% and 100%, respectively. The method developed was able to differentiate successfully all brands of pen used on each type of paper and could be a helpful tool for detection and confirmation of counterfeits in documents of legal importance.

Comparison of two approaches to performing an inferior alveolar nerve block in the horse

To compare two approaches to performing the inferior alveolar nerve block in the horse and to evaluate the consistency of described topographical landmarks. Experimental cadaver model. Eleven cadaver heads were positioned to mimic a standing sedated horse and the position of the mandibular foramen approximated. The vertical approach to the approximate location of the mandibular foramen was undertaken and red dye was deposited. The angled approach was then undertaken and blue ink was used to identify it. The heads were then dissected to determine the location of the dye. Placement was categorised as a hit or a miss for each technique for each side of the head. The distance of the dye from the nerve was recorded. Straight lateral radiographs of the sectioned heads were taken to evaluate the topographical landmarks for performing this nerve block. Each method was performed 22 times. A hit was achieved 16 times (73%) for the angled approach and 13 times (59%) for the vertical approach. There was no significant difference between the two approaches (P = 0.34). Radiographs revealed that the topographical landmarks used to approximate the mandibular foramen were relatively accurate. Both methods were found to be equivalently accurate. The previously reported topographic landmarks for locating the approximate position of the mandibular foramen on the medial aspect of the mandible were found to be accurate, but currently recommended doses of local anaesthetic may be excessive.

Phantom Study of a Novel Stereotactic Prostate Biopsy System Integrating Preinterventional Magnetic Resonance Imaging and Live Ultrasonography Fusion

To determine the targeting error of a novel stereotactic prostate biopsy system that integrates preinterventional MRI with peri-interventional ultrasonography (US) for perineal navigated prostate biopsies. We performed stereotactic biopsies on five prostate phantoms (one CIRS 053-MM and four CIRS 066). Phantom 053-MM incorporates three MRI- and transrectal ultrasonography (TRUS)-visible lesions, while lesions within phantom 066 are only detectable on MRI. In both phantoms, the 0.5 cc volume lesions are placed randomly. The phantoms were examined by 3T-MRI preinterventionally. Then three stereotactic biopsies from one lesion in phantom 053-MM and from all US-invisible lesions in the 066 phantoms were taken under live-fusion imaging guidance. During intervention, a mix of blue ink and gadobutrol was injected into each biopsy channel. Afterward, another 3T-MRI was obtained. These MRI images were then fused again with the intraoperative TRUS data. Thus, the targeting error (TE) between the planned and performed biopsy cores could be measured. In addition, the procedural targeting error (PTE) between the virtually planned biopsy trajectory and the manually registered three-dimensional needle position of every single biopsy core taken was calculated. The overall TE of the 39 biopsy cores taken was 0.83 mm (standard deviation [SD]: 0.48 mm) with the highest TE in the sagittal plane (1.09 ± 0.54 mm), followed by the coronal (0.72 ± 0.43 mm) and axial (0.69 ± 0.34 mm) planes. The procedural TE, which is provided intraoperatively, was 0.26 mm on average (SD: 0.46 mm). Comparing PTE and TE, there was no statistically significant difference (P=0.39). The TE of stereotactic biopsies using our novel perineal prostate biopsy system is below 1 mm and can be estimated in vivo by the automatically calculated procedural TE. Thus, stereotactic prostate biopsies guided by the combination of MRI and US allow effective and precise examination of MRI lesions.

Differentiation and dating of gel pen ink entries on paper by laser desorption ionization- and quadruple-time of flight mass spectrometry

The approaches for differentiation and dating of gel pen ink entries have been investigated by laser desorption ionization-time of flight mass spectrometry (LDI-TOF-MS) and high performance liquid chromatography-quadruple-time of flight mass spectrometry (HPLC-Q-TOF-MS). 45 kinds of black and blue gel pen ink entries were differentiated individually by the profiles of their LDI-MS spectra. The dye components in the black and blue ink entries have been identified by thin layer chromatography and HPLC-Q-TOF-MS methods. The degradation processes of the dye components in the ink entries under various aging conditions have been probed by LDI-MS approach. The results showed that the variations of relative intensities for the main dye components have a close relationship with aging time, and the degradation of the main dye components were significant under natural storage conditions, which can provide important evidences for dating of the ink entries on paper.

Characterization and Dating of Blue Ballpoint Pen Inks Using Principal Component Analysis of UV–Vis Absorption Spectra, IR Spectroscopy, and HPTLC

The ink of pens and ink extracted from lines on white photocopier paper of 10 blue ballpoint pens were subjected to ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR), and high-performance thin-layer liquid chromatography (HPTLC). The R(f) values and color tones of the bands separated by thin-layer chromatography (TLC) analysis used to classify the writing inks into three groups. The principal component analysis (PCA) investigates the pen responsible for a piece of writing, and how time affects spectroscopy of written ink. PCA can differentiate between pen ink and ink line indicates the influence of solvent extraction process on the results. The PCA loadings are useful in individualization of a questioned ink from a database. The PCA of ink lines extracted at different times can be used to estimate the time at which a questioned document was written. The results proved that the UV-Vis spectra are effective tool to separate blue ballpoint pen ink in most cases rather than IR and HPTLC.

A study of the evaporation of a solvent from a solution—Application to writing ink aging

When writing ink is placed on a substrate, a drying process begins. This process is dependent on the composition of the ink and of the substrate. Lociciro et al. provide an equation that describes the drying process based on models developed by earlier investigators. The work given here develops an equation for the drying process that is based on a different and rather simple model. This model considers the evaporation of a solution in an opened vertical container (e.g., a beaker) and consists of a volatile, non-hygroscopic solvent with a non-volatile solute dissolved in it. Three assumptions are made: (a) the rate of evaporation is proportional to the vapor pressure of the solution and to the solution's exposed surface area, (b) this solution vapor pressure is proportional to the solvent vapor pressure with the proportionality constant being the solvent mole fraction (Raoult's law), and (c) a small fraction of the solvent remains trapped in the solute after evaporation ceases. What results is a differential equation, which, when solved, gives the solvent weight W(t) as an implicit function. What emerges naturally from this treatment is the fact that the function W(t) can have a point of maximum acceleration. Prior to this point the drying process is fast and after this point, the drying process is slow. An approximation to W(t) is taken to be the sum of two exponential functions, one describing the fast drying region and the second describing the subsequent slow drying region. Upon including an additive constant, this approximation turns out to be similar to, but not the same as that provided by Lociciro et al. However, their equivalence is shown and then tested using the two inks examined by Lociciro et al. (the drying of a Bic and a Staedtler blue ballpoint ink). The examples of (solvent+solute) systems ("inks") given here consist of the solvent (2-phenoxyethanol) and a solute such as a dye (crystal violet) or a polymer resin such as synthetic resin SK or polyvinyl butyral. In the case of polymers, the Raoult's law assumption is replaced with one developed by the Flory-Huggins theory of solutions. Saturation and film formation, both of which slow the evaporation rate, are also discussed.

Visualization of the Penetration Depth of Plasma in Three-Dimensional Porous PCL Scaffolds

A dielectric barrier discharge (DBD) discharge is used to modify the surface properties of 3-D porous polycaprolactone (PCL) scaffolds. After plasma treatment, the penetration of blue ink into the samples was used to determine the effectiveness of the plasma treatment inside the structures. It was found that the ink could penetrate deeper into the scaffolds after plasma treatment.

The dimension of somatization is related to an increased color-word Stroop effect

CONGRUENT INCONGRUENT RED RED Example Stroop Stimuli The classic color-word Stroop task is a wellknown and widely used neuropsychological measure that requires individuals to view color-words (e.g., “red”) in an ink color that is either congruent (the word “red” in red ink) or incongruent ( the word “red” in blue ink). The individual’s task is to identify the color of the ink while ignoring the written word. During the task, the individual’s average reaction time within each condition is measured. The Stroop effect refers to an increase in reaction time in identifying the color of the incongruent compared to the congruent stimuli. Recent neuroimaging reviews indicate that the anterior cingulate cortex (ACC) is involved in regulating cognitive demands during the Stroop task, including error detection and response conflict (Bush et al., 2000; Carter and van Veen, 2007). Therefore, it has been suggested that performance on the Stroop task is sensitive to individual differences in ACC functioning (Carter et al., 1995). A recent study has demonstrated that an increase in the dimension of delusion-proneness, or propensity to hold beliefs that are dismissed as false or bizarre by members of the same socio-cultural group (Gilleen & David, 2005), was related to a greater color-word Stroop effect (Orem & Bedwell, 2010). Therefore, this association may relate to a deficiency in the ACC in monitoring errors in beliefs vs. reality. As different dimensions of psychopathology include different levels of delusional thought processes, we were interested in examining how a wide range of dimensions of psychopathology would relate to the Stroop effect. The Brief Symptom Inventory, or BSI, assesses for a wide variety of psychological symptoms. Within the various domains assessed by this measure, Somatization, Paranoid Ideation, and Psychoticism all include varying levels of delusionproneness. Specifically, Somatization includes complaints of physical symptoms that appear to be related primarily to psychological distress, Paranoid Ideation includes explicit delusional thought, and Psychoticism includes hallucinations and perceived thought control. Therefore, we hypothesized that the Stroop effect would be positively related to these three domains, supporting the ACC’s role in monitoring errors in beliefs vs. reality. Participants:  42 undergraduate students  Mean age of 19.30 years (SD = 2.28; Range = 18 – 32)  71.4% Female  71.4% Caucasian

Single step modified ink staining for Tzanck test: Quick detection of herpetic giant cells in Tzanck smear

Tzanck test has been recently re-evaluated as a method for the diagnosis of herpes virus infection. Giemsa staining for the Tzanck test is time-consuming and laborious. There is a need to develop simple and quick staining methods for bedside diagnosis of this disease. We report a single step and quick method for staining herpes giant cells in Tzanck smears using routinely available inks and physiological saline. A keratinocyte cell line (HaCaT) was cultured on a slide glass and stained with various commercially available blue, blue-black and black inks serially diluted with physiological saline. Clinical smear samples from herpes lesions were also stained with these solutions without specific pretreatment. The nuclei of HaCaT were clearly stained showing high contrast with the cytoplasm using 5% Parker-Quink blue-black ink saline solution. Concentration of ink solution higher or lower than 5% resulted in less contrast. Blue or black inks or other manufacturers' inks can also be used, but staining of the cultured keratinocytes was less clear. Smear of clinical samples from herpes lesions were also stained with 5% ink solution. The nuclei of the multinucleated giant cells were clearly stained, and the sample could be immediately used for microscopic examination. One step staining of Tzanck smear using this diluted ink solution is an inexpensive and a convenient bedside diagnostic tool for the dermatologist.

Multivariate classification of pigments and inks using combined Raman spectroscopy and LIBS

The authenticity of objects and artifacts is often the focus of forensic analytic chemistry. In document fraud cases, the most important objective is to determine the origin of a particular ink. Here, we introduce a new approach which utilizes the combination of two analytical methods, namely Raman spectroscopy and laser-induced breakdown spectroscopy (LIBS). The methods provide complementary information on both molecular and elemental composition of samples. The potential of this hyphenation of spectroscopic methods is demonstrated for ten blue and black ink samples on white paper. LIBS and Raman spectra from different inks were fused into a single data matrix, and the number of different groups of inks was determined through multivariate analysis, i.e., principal component analysis, soft independent modelling of class analogy, partial least-squares discriminant analysis, and support vector machine. In all cases, the results obtained with the combined LIBS and Raman spectra were found to be superior to those obtained with the individual Raman or LIBS data sets.

Reduced Chondrocyte Viability Is Associated With the Use of Surgical Marker Pen Ink

Background: Sterile surgical marker pens are commonly used in cartilage repair surgery to aid in the placement of periosteal patches or collagen membranes in autologous chondrocyte implantation. Purpose: To investigate the effects that methylene blue and crystal violet marker pen ink have on human chondrocytes when cultured on collagen membranes in vitro. Study Design: Controlled laboratory study. Methods: Human chondrocytes were applied to Chondro-Gide collagen membranes at a volume of 12 million cells. In the first experiment, 2 sterile marker pens, one containing methylene blue and the other crystal violet inks, were used to mark membranes immediately before the addition of cells. In the second experiment, the same marker pens marked the membranes after 7 days of cell culture. In each experiment, 3 groups of membrane were tested for each pen. Group A consisted of no ink mark, group B had only the uppermost “smooth” layer marked, and group C had the lower “porous” layer marked. All membranes were then cultured in standard growth media for 24 hours. Cell viability was assessed at 24 hours on all membranes using a live/dead-cell viability assay. Cell viability was quantified with florescent microscopy with mean percentage of live cells in each marker pen group compared with control membranes using the Student t test (P < .05). Results: Control membranes (group A) with no ink showed cell viability approaching 100%. A statistically significant reduction in cell viability with both methylene blue (23.1%; P < .0001) and crystal violet (18.9%; P < .0001) was found adjacent to the ink mark on the smooth side (group B) and on the porous side remote from the ink (group C) in both experiments (<30%; P < .0001). Areduction in cell viability was noted on the smooth side remote from the ink mark but did not reach statistical significance. Marked cell death was seen with both dyes (<15%; P < .0001) adjacent to the ink on the porous side. Conclusion: Chondrocyte viability is significantly reduced when cells are cultured in vitro on collagen membranes marked with methylene blue and crystal violet pen ink. Clinical Relevance: Surgeons should be aware of the potential negative effect of marker pens in cell-based therapies.

History for Timbuktu: Aḥmad Bul‘arāf, Archives, and the Place of the Past

Aḥmad Bul‘arāf died in September 1955 and was buried in his adopted Timbuktu. He was laid to rest in the town's Sīdi al-Wāfi al-Amīr al-Arawāni cemetery but it would be hard to identify his grave. Gravestones soon disappear into their natural sandy settings. At the time he was widely eulogized for his life's work as a man of religion, culture, and knowledge. Well-known scholars and copyists of his era composed panegyric verses in his honour. One wrote:What a pity on the sciences and their books/On their owners when this calamity occurred/Their schools and places have become deserted/There's no one in them except crows and vultures/Suddenly today there is a caller and no one to respond/Except the echoes and the tunes of the winds/By Ahmad Bui ‘arāf they were granted a gift/How many lessons were conducted and/You have upheld their loftiness, established their origin/You maintained their essence with your honorable books.Decades later he still lives on in the memories of scholars as a “great hero and famous scholar, reviver of Islamic culture,” as a young writer described him in 1986, in a carefully handwritten essay in a local calligraphic style devoted to his achievement. Composed in “Sudani” script in blue ink with headings in red, when the typewriter, if not the PC, had long ago arrived in the region, this encomium to Bui‘arāf was a fitting tribute to a man who loved the written word. He cared for ideas expressed on paper, for their circulation, and how books could be stored for use in the present and in the future. He was devoted to conserving the manuscript heritage of Timbuktu. His own calligraphy in various regional variants was widely recognized and he practiced it without hesitation in the print age.

Luminescent nanomaterials containing rare earth ions for security printing

The high-efficiency luminescent nanomaterials with different emission wavelengths of red (YVO4:Eu3+), green (CePO4:Tb3+), ZnS:Mn2+ and YVO4:Eu3+;@SiO2 were successfully prepared with different concentrations of Mn and rare earth ions as active centres by chemical synthesis. Structure properties were studied. It was found that the particle size of our samples was in the range of 10-30 nm. Photoluminescent properties were studied under 325, 337, 365 and 370 nm excitations in order to apply in luminescent labels. The primary colour components are red and green emission making them very convenient and attractive for screen security printing systems. Hundreds of different labels with a size of 1-10 cm² were prepared by screen-printing as well as inkjet printing. By improving the Epson printer, commercial red, green and blue inks were used in the printing application. Screen and inkjet printing were deemed good methods for security printing. Our products were beautiful, high resolution and withstood tropical weather.

Today You Are A Man

Superman on Batman. The weight of them bound together. Sharp smells of yellow and blue ink, cold aluminum shelving, cardboard dust. Flaking spines repeat amazing amazing amazing. Higher up, Will Eisner's thick digests of tenement stories trace his grandparents' bent backs and Yiddish rants in scrolling lines of brown on white. Green Jell-O alien fingers probe some space-blonde's inflated tits. Peter breathes them in, these particles of floating worlds. Today you are a man. He's so hopeless only a spider can save him, and not the one who told Wilbur's farmer to keep kosher. Bedtime stories from before he was the horse in the Purim play, every year. Bending over in the stockroom, he hoists another box of SHAZAMl, his body big but flabby at thirteen. The way he bends over to talk to his father, or rather to listen, one word to Nathan's clever dozen. In a comic book, Nathan would be the red-headed scientist who convinced Congress to build a Mars launch out of rubber bands. He would persuade Steve Trevor to stick around and look pretty though Wonder Woman would never, ever marry him, and by the way, just because she disappears at odd hours and you found star-spangled underwear in the hamper, there's no evidence that she's living a double life. Peter realizes he's too interested in what happens to Steve. He wants to be one of the chosen ones. He works hard and doesn't sit back here all day reading while his boss Jonas smokes another joint at the cash register, his chair tilted back against a wall layered with drawings of dragon fangs and lightning-bolt fists. Laconic, lean Gary Jonas is his father's friend, but he acts like Peter will amount to something. Enough to dress him up as the Jolly Green Giant in the Greenwich Village Halloween parade, with Jonas and his friends as the Fruit of the Loom guys. Peter's parents are open-minded, except his mother, but soon she won't count anymore. Three hundred copies of Popeye. Underneath them the good stuff, the wide-eyed, round-assed elfin girls, which Peter doesn't look at. Bending over in the stockroom.

A statistical methodology for the comparison of blue gel pen inks analyzed by laser desorption/ionization mass spectrometry

A statistical methodology for the objective comparison of LDI-MS mass spectra of blue gel pen inks was evaluated. Thirty-three blue gel pen inks previously studied by RAMAN were analyzed directly on the paper using both positive and negative mode. The obtained mass spectra were first compared using relative areas of selected peaks using the Pearson correlation coefficient and the Euclidean distance. Intra-variability among results from one ink and inter-variability between results from different inks were compared in order to choose a differentiation threshold minimizing the rate of false negative (i.e. avoiding false differentiation of the inks). This yielded a discriminating power of up to 77% for analysis made in the negative mode. The whole mass spectra were then compared using the same methodology, allowing for a better DP in the negative mode of 92% using the Pearson correlation on standardized data. The positive mode results generally yielded a lower differential power (DP) than the negative mode due to a higher intra-variability compared to the inter-variability in the mass spectra of the ink samples.

Chronic cannabis users show altered neurophysiological functioning on Stroop task conflict resolution

Chronic cannabis use has been related to deficits in cognition (particularly memory) and the normal functioning of brain structures sensitive to cannabinoids. There is increasing evidence that conflict monitoring and resolution processes (i.e. the ability to detect and respond to change) may be affected. This study examined the ability to inhibit an automatic reading response in order to activate a more difficult naming response (i.e. conflict resolution) in a variant of the discrete trial Stroop colour-naming task. Event-related brain potentials to neutral, congruent and incongruent trials were compared between 21 cannabis users (mean 16.4 years of near daily use) in the unintoxicated state and 19 non-using controls. Cannabis users showed increased errors on colour-incongruent trials (e.g. "RED" printed in blue ink) but no performance differences from controls on colour congruent (e.g. "RED" printed in red ink) or neutral trials (e.g. "*****" printed in green ink). Poorer incongruent trial performance was predicted by an earlier age of onset of regular cannabis use. Users showed altered expression of a late sustained potential related to conflict resolution, evident by opposite patterns of activity between trial types at midline and central sites, and altered relationships between neurophysiological and behavioural outcome measures not evident in the control group. These findings indicate that chronic use of cannabis may impair the brain's ability to respond optimally in the presence of events that require conflict resolution and hold implications for the ability to refrain from substance misuse and/or maintain substance abstention behaviours.

Differentiation of blue ballpoint pen inks by positive and negative mode LDI-MS

Usually, the differentiation of inks on questioned documents is carried out by optical methods and thin layer chromatography (TLC). Therefore, spectrometric methods were also proposed in forensic literature for the analysis of dyes. Between these techniques, laser desorption/ionization mass spectrometry (LDI-MS) has demonstrated a great versatility thanks to its sensitivity to blue ballpoint ink dyes and minimal sample destruction. Previous researches concentrated mostly on the LDI-MS positive mode and have shown that this analytical tool offers higher discrimination power than high performance TLC (HPTLC) for the differentiation of blue ballpoint inks. Although LDI-MS negative mode has already been applied in numerous forensic domains like the studies of works of art, automotive paints or rollerball pens, its potential for the discrimination of ballpoint pens was never studied before. The aim of the present paper is therefore to evaluate its potential for the discrimination of blue ballpoint inks. After optimization of the method, ink entries from 33 blue ballpoint pens were analyzed directly on paper in both positive and negative modes by LDI-MS. Several cationic and anionic ink components were identified in inks; therefore, pens were classified and compared according to their formulations. Results show that additional information provided by anionic dyes and pigments significantly increases the discrimination power of positive mode. In fact, it was demonstrated that classifications obtained by the two modes were, to some extent, complementary (i.e., inks with specific cationic dyes not necessarily contained the same anionic components).

Effect of Aging on Coronal Microleakage in Access Cavities through Metal Ceramic Crowns Restored with Resin Composites

The purpose of this in vitro study was to determine if packable resin composite with/without flowable resin composite has the ability to prevent coronal leakage in restored endodontic access openings following aging. Eighty simulated standardized access cavities of metal-ceramic crowns were fabricated and fixed on Vitrebond cavities filled with an epoxy resin. The specimens were randomly divided into two main groups: (1) Group A-Access cavities filled with only packable composite (Filtek P60); (2) Group B-Access cavities filled with Filtek P60 and a flowable composite (Filtek Z350) as liner. Each main group was further subdivided randomly into four subgroups according to water storage and thermocycling periods. All specimens were immersed in blue ink solution for 24 hours and then sectioned into quadrants. The extension of blue ink along the metal-ceramic crown/composite resin interface was measured linearly using image analyzer and then analyzed by three-way ANOVA and independent t-test with a Mann-Whitney test. The level of significance was set at p < 0.05. All tested subgroups demonstrated different levels of microleakage. There was no significant difference related to restorative technique; however, there was a significant difference related to water storage and thermocycling. All tested techniques and materials in this study showed microleakage. Packable composite while a flowable liner showed a marginally better result than packable composite alone. Excessive thermocycling resulted in significant differences among the test groups.

Features of Stroop and Reverse-Stroop Interference: Analysis by Response Modality and Evaluation

Stroop interference (the Stroop effect) is the phenomenon observed when naming the color of an incongruent stimulus, such as the word "red" printed in blue ink; typically, this color incongruence causes slower naming compared to a neutral stimulus, such as a blue square patch. Reverse-Stroop interference occurs when reading the stimulus takes longer than reading the neutral stimulus. Features of Stroop and reverse-Stroop interference were examined, focusing on the difference between the response modalities--oral response and manual response--and the difference between methods of evaluating performance (time or correct responses) and the interference score. Participants were 47 students (30 women, 17 men; M age=20.8 yr., range=19-29). The results were as follows: (1) the performance of the reverse-Stroop condition was higher than that of the Stroop condition for both oral and manual responses; (2) the Stroop interference score was significantly greater with the oral response than with the manual response; and (3) the reverse-Stroop interference score was constant regardless of the response modality. The results were discussed with respect to differences in processing speeds of verbal and sensory information.