What have Klingon letters and faces in common? An fMRI study on content-specific working memory systems

Neuroimaging studies show that prefrontal, premotor, and parietal cortical regions are part of a working memory network that supports the active retention of information. In two experiments we used fMRI to examine whether prefrontal and posterior cortical areas are organized in a content-specific way for object and spatial working memory. Subjects performed a delayed matching-to-sample task modified to allow the examination of content-specific retention processes, independent of perceptual and decision-related processes. In Experiment 1, either unfamiliar geometrical objects (Klingon letters from an artificial alphabet unknown to the participants) or their spatial locations had to be memorized, whereas in Experiment 2, either unfamiliar faces or biological objects (butterflies) were actively memorized. All tasks activated a similar cortical network including posterior parietal (banks of the intraparietal sulcus), premotor (banks of the inferior precentral sulcus) and prefrontal regions (banks of the inferior frontal sulcus), and the presupplementary motor area (pre-SMA). For geometrical objects and faces for which strategic semantic processing can be assumed, this activation was larger in the left than in the right hemisphere, whereas a bilateral or right dominant distribution was obtained for butterflies and spatial locations. The present results do not support the process-specific or content-specific view of the role of the prefrontal cortex in working memory task. Rather, they suggest that the inferior prefrontal cortex houses nonmemonic strategic processing systems required for response selection and task management that can flexibly be used across a variety of tasks and informational domains.     

Automated calibration in vascular X-ray images using the accurate localization of catheter marker bands

RATIONALE AND OBJECTIVES: To develop a new automated calibration method for vessel measurements in vascular x-ray images. METHODS: Radiopaque marker bands mounted equidistantly on a small catheter were acquired in vitro at five image intensifier (II) sizes in x-ray projection images. The positions of the marker centers were detected by using a Hough transform and were computed at subpixel precision by using either a novel, iterative center-of-gravity approach (CGA) or a symmetry filter. Curve-fitting procedures were used to reject false-positive marker detections and to calculate intermarker distances. The calibration factor was calculated from the true marker distance and the average of the measured distances in pixels. Results were compared statistically with a grid calibration method, which was taken as the gold standard. A simulation study was performed to assess the influence of image noise on the CGA method. RESULTS: The iterative CGA method was convergent and faster than the symmetry-based technique. For four II sizes (17, 20, 25, and 31 cm), the results from the CGA method were not significantly different from the results obtained with grid calibration. For the II size of 38 cm, a significant difference (0.3% of the grid calibration factor) was found; however, this was caused by the quantification error in the image data and was not clinically relevant. In general, the performance of the CGA method improved with increasing signal-to-noise ratio. CONCLUSIONS: A practical new calibration method for small catheter sizes was developed and validated for quantitative vascular arteriography.     

Factors causing differences in voiding parameters between conventional and ambulatory urodynamics

Voiding parameter values measured with ambulatory urodynamic monitoring (AM) are generally found to be different from those measured with conventional cystometry (CMG). The reason for this is unclear, but might be related to differences in the voided volume. To verify this hypothesis, we compared voidings from female patients at an initial bladder volume that was close to the modal volume (that is, the volume most often voided by the patient as derived from frequency/volume charts) with voidings at maximum cystometric capacity during a routine video urodynamic examination. A first group of 35 patients voided at the modal volume before they did at capacity. The order was reversed in a second group of 12 patients. The dependence of the voiding parameters on the voided volume and the order of the measurements were examined. It was found that the maximum flow rate depended significantly on the voided volume, but the associated detrusor pressure did not. Urethral resistance and bladder contraction strength were not volume dependent either. It was concluded that the differences between AM and CMG cannot be explained from possible differences in the voided volume. Received: 23 August 1999 / Accepted: 16 December 1999     

High tolerance for oral galactose in classical galactosaemia: dietary implications.

AIM: To study the relevance of restricting the exogenous intake of small amounts of galactose, such as from fruit and vegetables, in patients with classical galactosaemia. METHODS: For a period of six weeks, increasing doses of oral galactose to a maximum of 600 mg per day, were added to a very strict galactose restricted diet in three adolescent patients homozygous for the Q188R mutation. During the study, physical examination, including an extended ophthalmic examination, and laboratory studies were performed on a weekly basis. RESULTS: No significant change in any of the studied clinical or biochemical parameters was observed. CONCLUSIONS: These findings provide further evidence that attempts to exclude trace amounts of galactose from the diet are not justified. Once the diet is made more liberal, a long term follow up study will be necessary.     

Results of 58872 and 58921 trials in acute myeloblastic leukemia and relative value of chemotherapy vs allogeneic bone marrow transplantation in first complete remission: the EORTC Children Leukemia Group report.

The first EORTC (European Organization of Research and Treatment of Cancer) acute myeloblastic leukemia (AML) pilot study (58872) was conducted between January 1988 and December 1991. Out of 108 patients, 78% achieved complete remission (CR), and event-free survival (EFS) and survival rates (s.e., %) at 7 years were 40 (5) and 51% (6%), respectively. It indicated that mitoxantrone could be substituted for conventional anthracyclines in the treatment of childhood AML without inducing cardiotoxicity. The aim of the next EORTC 58921 trial was to compare the efficacy and toxicity of idarubicin vs mitoxantrone in initial chemotherapy courses, further therapy consisting of allogeneic bone marrow transplantation (alloBMT) in patients with an HLA-compatible sibling donor or chemotherapy in patients without a donor. Out of 177 patients, recruited between October 1992 and December 2002, 81% reached CR. Overall 7-year EFS and survival rates were 49 (4) and 62% (4%), respectively. Out of 145 patients who received the first intensification, 39 had a sibling donor. In patients with or without a donor, the 7-year disease-free survival (DFS) rate was 63 (8) and 57% (5%) and the 7-year survival rate was 78 (7) and 65% (5%), respectively. Patients with favorable, intermediate and unfavorable cytogenetic features had a 5-year EFS rate of 57, 45 and 45% and a 5-year survival rate of 89, 67 and 53%, respectively.     

Compensation of cyclophosphamide immunosuppression by a bacterial immunostimulant (Broncho-Vaxom) in mice

The compensatory effect of a bacterial lysate, Broncho-Vaxom (BV) on the immunosuppressive action of cyclophosphamide (CY) was investigated. In CY immunosuppressed mice, BV treated animals recovered to normal levels of IgM and IgG in serum as well of IgA and IgG in gut secretions significantly earlier than controls. Furthermore, normal cell proliferation in thymus, as estimated by measuring the relative size of this organ was achieved earlier in BV treated mice than in control mice. Oral treatment with BV restores the number of IgM anti SRBC producing cells in spleen, in CY immunosuppressed mice. Since immunosuppression induced by CY increases the susceptibility to various infections, we tested in immunosuppressed animals the protective effect of BV towards IP challenge infections with Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae var ozaenae, Pseudomonas aeruginosa and Candida albicans. BV led to an enhanced resistance towards both pneumococci and staphylococci challenge infections but not to the other challenge microorganisms.     

Age at sexual initiation and number of sexual partners in the female Spanish population Results from the AFRODITA survey

Objectives

The AFRODITA study was designed to describe patterns relating to the number of lifetime sexual partners (SP) and age at first sexual intercourse (AFSI) by geographic region in a representative sample of Spanish women.

Study design

A representative sample of the female Spanish population was obtained using the Access Panel Technique. Postal questionnaires were sent to 11,086 women aged 18–70 years. Data were collected on AFSI, number of sexual partners, contraceptive methods, cervical cancer screening and socio-demographic characteristics.

Results

The average AFSI was 20.9 years. AFSI below the age of 19 years was reported by 30.8% of the women. Among sexually active women, 70.6% reported being monogamous and 6.4% reported ≥5 lifetime sexual partners. Younger age at interview was strongly related to earlier AFSI and to higher number of lifetime sexual partners. Women younger than 25 were 39 times more likely to have an AFSI before age 18 than women over age 55. The percentage of women aged less than 25 reporting two or more sexual partners was four times higher than that of women 56 and older. In the multivariate analysis, having two or more sexual partners was independently associated with young age, early AFSI, having ever used oral contraceptives, living in an urban area, having had a screening Pap test in the last 3 years, having a sexually transmitted infection and nuliparity.

Conclusions

This study confirms important changes in the sexual behaviour of Spanish women. Younger cohorts show a younger age at sexual initiation and higher number of sexual partners. These are key factors that may induce changes in the human papillomavirus (HPV) prevalence and the cervical cancer incidence in Spain.     

Removal of Stair-Step Effects in Binder Jetting Additive Manufacturing Using Grayscale and Dithering-Based Droplet Distribution

Binder jetting is a layer-based additive manufacturing process for three-dimensional parts in which a print head selectively deposits binder onto a thin layer of powder. After the deposition of the binder, a new layer of powder is applied. This process repeats to create three-dimensional parts. The binder jetting principle can be adapted to many different materials. Its advantages are the high productivity and the high degree of freedom of design without the need for support structures. In this work, the combination of binder jetting and casting is utilized to fabricate metal parts. However, the achieved properties of binder jetting parts limit the potential of this technology, specifically regarding surface quality. The most apparent surface phenomenon is the so-called stair-step effect. It is considered an inherent feature of the process and only treatable by post-processing. This paper presents a method to remove the stair-step effect entirely in a binder jetting process. The result is achieved by controlling the binder saturation of the individual voxel volumes by either over or underfilling them. The saturation is controlled by droplet size variation as well as dithering, creating a controlled migration of the binder between powder particles. This work applies the approach to silica sand particle material with an organic binder for casting molds and cores. The results prove the effectiveness of this approach and outline a field of research not identified previously.