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The aim of the present study was to compare the cerebral activation associated with encoding and retrieval in individual subjects with the average activation in the same group of subjects. Twelve volunteers performed two paradigms: 1) intentional encoding of words, and 2) recognition of learned words intermixed with new distracters. Echo-planar magnetic resonance imaging (MRI) of BOLD signal changes was used to compare cerebral activation between active and resting conditions. During encoding, activation of the left precentral gyrus related to the motor response was observed in some subjects. Averaged data showed increased activation of the left precentral gyrus, the supplementary motor area (SMA), the left inferior frontal gyrus and in the left temporo-occipital junction. During recognition, motor response-related activity was found in the precentral cortex and SMA in most subjects. Activation in other brain areas showed considerable interindividual variation. In the entire group, recognition showed activation of the left dorsolateral prefrontal cortex, the precentral gyrus, the SMA, and the temporo-occipital junction. The total amount and the distribution of task-related cerebral activation varies considerably between individuals and might correspond to individual preferences of cognitive strategies. The investigation of these interindividual variations will be an exciting scientific challenge in the near future.
Objectives. – Studies on the relation between local cerebral activation and retrieval success usually compared high and low performance conditions, and thus showed performance-related activation of different brain areas. Only a few studies directly compared signal intensities of different response categories during retrieval. During verbal recognition, we recently observed increased parieto-occipital activation related to false alarms. The present study intends to replicate and extend this observation by investigating common and differential activation by veridical and false recognition.
Methods. – Fifteen healthy volunteers performed a verbal recognition paradigm using 160 learned target and 160 new distracter words. The subjects had to indicate whether they had learned the word before or not. Echo-planar MRI of blood-oxygen-level-dependent signal changes was performed during this recognition task. Words were classified post hoc according to the subjects’ responses, i.e. hits, false alarms, correct rejections and misses. Response-related fMRI-analysis was used to compare activation associated with the subjects’ recognition success, i.e. signal intensities related to the presentation of words were compared by the above-mentioned four response types.
Results. – During recognition, all word categories showed increased bilateral activation of the inferior frontal gyrus, the inferior temporal gyrus, the occipital lobe and the brainstem in comparison with the control condition. Hits and false alarms activated several areas including the left medial and lateral parieto-occipital cortex in comparison with subjectively unknown items, i.e. correct rejections and misses. Hits showed more pronounced activation in the medial, false alarms in the lateral parts of the left parieto-occipital cortex.
Conclusions. – Veridical and false recognition show common as well as different areas of cerebral activation in the left parieto-occipital lobe: increased activation of the medial parietal cortex by hits may correspond to true recognition, increased activation of the parieto-occipital cortex by false alarms may correspond to familiarity decisions. Further studies are needed to investigate the reasons for false decisions in healthy subjects and patients with memory problems.
Attention deficit / hyperactivity disorder (ADHD) affects about 60% of adults who suffered from ADHD in childhood. Methylphenidate is a common off-label treatment.
The aim of this pilot study was to assess the neuropsychological effects of a single dose of methylphenidate (10 mg orally) on different attention components and executive functions by using the computerized attention assessment battery TAP 2.2 (Testbatterie zur Aufmerksamkeitsprüfung).
Fifteen DSM IV-ADHD adult patients were enrolled into this study. Neuropsychological evaluations were performed at baseline and after the methylphenidate test. Patients were subsequently treated with adequate dose of methylphenidate and followed over a period of 6 months.
Compared with baseline, a single dose of methylphenidate induced a significant improvement in working memory (p = 0.001), sustained attention (p = 0.0007) and visual scanning (p = 0.0007) in terms of omissions and mistakes. Reaction times also decreased in tonic arousal (p = 0.002), incompatibility (p = 0.008) and flexibility tasks (p < 0.00001). There was a significant correlation between working memory and sustained attention before and after methylphenidate (both p < 0.01). Among our patients, 12 who responded positively to the methylphenidate test, showed favorable long-term outcome with methylphenidate treatment.
Adults with ADHD showed neurocognitive improvements after a single 10 mg dose of methylphenidate. Our results suggest that the methylphenidate test would be useful in predicting subsequent response to methylphenidate treatment in ADHD adult patients. Controlled prospective studies are needed to confirm this hypothesis.
We previously demonstrated that the difference between 23.00h and 08.00h TSH response to TRH tests on the same day (ΔΔTSH test) is reduced in about 75% of drug-free depressed inpatients. This study sought to determine whether this chronobiological index, at baseline and after 2 weeks of treatment, could predict antidepressant response.
The ΔΔTSH test was performed in 50 drug-free DSM-IV euthyroid major depressed inpatients and 50 hospitalized controls. After 2 weeks of antidepressant treatment the ΔΔTSH test was repeated in all inpatients. Antidepressant response was evaluated after 6 weeks of treatment.
At baseline, ΔΔTSH values were significantly lower in patients compared to controls (p< 0.000001): 38 patients showed reduced values (i.e. ΔΔTSH ≤ 2.5 mIU/L; sensitivity, 76%; specificity, 98%). After two weeks of treatment, 20 patients showed ΔΔTSH normalization (among them 18 were subsequent remitters), while 18 patients did not normalize their ΔΔTSH (among them 15 were non remitters) (p < 0.00001). Among the 12 patients who had normal ΔΔTSH values at baseline, 8 out 9 who had still normal values after 2 weeks of treatment were remitters, while the 3 with worsening thyroid axis function (i.e. reduced ΔΔTSH value after 2 weeks of treatment) were non-remitters (p< 0.02).
Our results suggest that after 2 weeks of antidepressant treatment: 1) an abnormal ΔΔTSH test could predict non-remission, and 2) ΔΔTSH normalization is associated with subsequent remission. Thus, chronobiological restoration of the thyroid axis activity precedes clinical improvement and may predict the therapeutic outcome in major depression.
The aim of this study was to investigate the relationship between suicidal behavior and chronobiological thyroid axis activity in depressed patients.
The serum levels of TSH, were evaluated before and after 8 AM and 11 PM TRH challenges, on the same day, in 230 medication-free DSM-IV euthyroid major depressed inpatients and 50 healthy hospitalized controls.
Compared to controls: 1) patients with a recent suicide attempt (n = 71) showed lower TSH response to TRH (ΔTSH) at 11 PM, lower ΔΔTSH values (differences between 11PM-ΔTSH and 8AM-ΔTSH) (p < 0.03 and p < 0.00001, respectively), and lower free thyroxine (FT4) levels (p < 0.00001); 2) patients with a past suicide attempt (n = 52) showed no major alteration of the HPT axis activity; 3) patients without a suicide attempt history (n = 107) showed both lower 8 AM-ΔTSH and 11-PM ΔTSH (p < 0.04 and p < 0.000001), and lower ΔΔTSH values (p < 0.000001), but no alteration of circulating thyroid hormone levels.
Our results suggest that in patients without a suicide attempt history increased hypothalamic TRH stimulation (as evidenced by reduced TSH responses to TRH) might be a compensatory mechanism. in patients with a suicide history this compensatory mechanism is not effective. in patients with a recent suicide attempt the evening TSH blunting, associated with reduced FT4 levels, might be indicative of a decreased central TRH activity leading to a reduction in the TSH resynthesis in the thyrotrophs during the day after the morning challenge.
The south-eastern Black Sea area is a key region for understanding the history of iron metallurgy. While Classical texts mention the people living in this area as producers, and perhaps even inventors, of iron, material evidence has been lacking. Recent archaeological survey and scientific analyses now make it possible to investigate iron technologies in the region during the mid to late first millennium BC and the medieval period, providing new insights into the metallurgical tradition that inspired such admiration in the Graeco-Roman world. These results have implications for the smelting of iron in liquid state, although it remains unclear where and when this technology first appeared in Western Eurasia.
The South Caucasus has been largely absent in broader discussions of prehistoric population aggregation in Greater Eurasia. The authors use remote sensing, surface collection and magnetometry to investigate two hilltop fortress settlements at the margins of the Kura River Basin, with a particular emphasis on satellite settlements around the main hills. The results support a model of settlement growth in which previously mobile groups settled around the fortress, while maintaining a degree of spatial and social separation. The use of multiple survey techniques reveals a complex picture of settlement organisation, with implications for comparative analysis of prehistoric population aggregation models.
Engineered non-wetting surfaces inspired by biological species are of interest in the industry due to their potential applications such as water repelling, self-cleaning, anti-icing, anti-corrosion, anti-fouling, and low fluid drag surfaces. However, the adoption of non-wetting surfaces in large scale industrial applications has been hampered by synthesis techniques that are not easily scalable and the limited long term stability and wear robustness of these surfaces in service. In this study, we demonstrate a simple, low cost, and scalable electrochemical technique to produce robust composite coatings with tunable non-wetting properties. The composite coatings are composed of an ultra-fine grain nickel matrix with embedded hydrophobic cerium oxide ceramic particles. Comprehensive characterization, including wetting property measurements, electron microscopy, focused ion beam analysis, hardness measurements, and abrasive wear testing were performed to establish the structure-property relationships for these materials. The grain refinement of the nickel matrix contributes to the high hardness of the composites. As a result of the bimodal CeO2 particle size, hierarchical roughness is present on the surface of the composite, leading to remarkable non-wetting properties, even after 720 m of abrasive wear.
The Eastern Black Sea region of the South Caucasus contains an extremely rich record of metallurgical remains that is poorly known outside of the former Soviet Union. Large numbers of relatively small smelting sites dot the foothill regions, forming a dispersed, yet large-scale metallurgical landscape. New fieldwork in the region has followed up on earlier Soviet period research, relocating and reanalyzing previously known sites and identifying new ones. This paper presents a series of 33 radiocarbon (14C) dates from copper and iron smelting sites in this region. Dates from copper smelting sites suggest that copper smelting occurred over a shorter and more intense period than previously thought, between about 1300 and 800 BC. Dates from newly discovered iron smelting sites place these activities in two episodes during the Classical-Hellenistic period (ca. 500–200 BC) and the High Medieval period (ca. AD 1050–1400). The dramatic expansion in bronze production immediately prior to the adoption of iron mirrors patterns in other regions of Europe and the Near East, and has implications for understanding the economic contexts in which iron emerged. While the new dates from iron smelting sites provide only an initial outline of the iron production chronology in the region, they represent an important step for resolving outstanding issues from previous investigations.
Archaeozoological research of Roman animal bones has a long tradition in Switzerland. In the 1950s, Elisabeth Schmid started analysing bones from the Roman city of Augusta Raurica. On the basis of these analyses she published her Atlas of Animal Bones (1972) which is still in use all over the world today. To date, more than 300,000 bone fragments from different Swiss sites have been analysed. In 2002 a synthesis of Swiss data was published by Jörg Schibler et al.; in that publication, the authors focused on social aspects. They assumed that the Roman animal economy was more or less standardized in the region, and that differences existed mainly between settlement types and within sites. In the last few years, not only have more data been recorded, but also other research questions about functional and regional difference—especially between western and eastern Switzerland (Germania Superior and Raetia)—are becoming more important. These differences show the variability and adaptability of the Roman economy.
A number of laser facilities coming online all over the world promise the capability of high-power laser experiments with shot repetition rates between 1 and 10 Hz. Target availability and technical issues related to the interaction environment could become a bottleneck for the exploitation of such facilities. In this paper, we report on target needs for three different classes of experiments: dynamic compression physics, electron transport and isochoric heating, and laser-driven particle and radiation sources. We also review some of the most challenging issues in target fabrication and high repetition rate operation. Finally, we discuss current target supply strategies and future perspectives to establish a sustainable target provision infrastructure for advanced laser facilities.
Infections and colonization with multidrug-resistant organisms (MDROs) identified >48 hours after hospital admission are considered healthcare-acquired according to the definition of the Centers for Disease Control and Prevention (CDC). Some may originate from delayed diagnosis rather than true acquisition in the hospital, potentially diluting the impact of infection control programs. In addition, such infections are not necessarily reimbursed in a healthcare system based on the diagnosis-related groups (DRGs).
The goal of the study was to estimate the preventable proportion of healthcare-acquired infections in a tertiary care hospital in Switzerland by analyzing patients colonized or infected with MDROs.
All hospitalized patients with healthcare-acquired MDRO infection or colonization (HAMIC) or according to the CDC definition (CDC-HAMIC) were prospectively assessed from 2002 to 2011 to determine whether there was evidence for nosocomial transmission. We utilized an additional work-up with epidemiological, microbiological, and molecular typing data to determine the true preventable proportion of HAMICs.
Overall, 1,190 cases with infection or colonization with MDROs were analyzed; 274 (23.0%) were classified as CDC-HAMICs. Only 51.8% of CDC-HAMICs had confirmed evidence of hospital-acquisition and were considered preventable. Specifically, 57% of MRSA infections, 83.3% of VRE infections, 43.9% of ESBL infections, and 74.1% of non-ESBL MDRO infections were preventable HAMICs.
The CDC definition overestimates the preventable proportion of HAMICs with MDROs by more than 50%. Relying only on the CDC definition of HAMICs may lead to inaccurate measurement of the impact of infection control interventions and to inadequate reimbursement under the DRG system.
The work hardening behavior of electrodeposited nanocrystalline nickel (29 and 19 nm) was investigated under multiaxial loading and compared with coarse-grained nickel. Plastic strain gradients were introduced into the materials using large Rockwell D hardness indentations, and measured through cross-sectional hardness profiles. The results showed that the coarse-grained material exhibited substantial hardening up to twice the hardness of the deformation-free area due to dislocation mediated deformation, while the nanocrystalline materials displayed small hardness variations along the strain gradient, indicative of considerably reduced dislocation interactions. Moreover, the grain structure analysis (cumulative volume fraction and size distribution) for the nanocrystalline materials suggested the operation of both dislocation mediated and grain boundary controlled deformation mechanisms, the latter becoming more significant with increasing cumulative sample volume of very small grains. The plastic deformation zone sizes under Rockwell indentation of the 29 nm Ni are similar to those conventional materials with reduced strain hardening. Microhardness-indentation size effects were negligible in both the nanocrystalline and coarse-grained materials.
This paper presents research in the development of heuristic evolutionary algorithms (EAs) for generating and exploring differentiated force-based structures. The algorithm is weighted toward design exploration of topological differentiation while including specific structural and material constraints. An embryological EA model is employed to “grow” networks of mass-spring elements achieving desired mesh densities that resolve themselves in tensile force (form-active) equilibrium. The primal quadrilateral quadrisection method serves as the foundation for a range of extensible subdivision methods. Unique to this research, the quad is addressed as a “cell” rather than a topological or geometric construct, allowing for the contents of the cell to vary in number of mass-spring elements and orientation. In this research, this approach has been termed the quadrilateral quadrisection with n variable topological transformation method. This research culminates with the introduction of a method for grafting meshes where emergent features from the evolved meshes can be transposed and replicated in an explicit yet informed manner. The EA and grafting methods function within a Java-based software called springFORM, developed in previous research, which utilizes a mass-spring based library for solving force equilibrium and allows for both active (manual) and algorithmic topology manipulation. In application to a specific complex tensile mesh, the design framework, which combines the generative EA and mesh grafting method, is shown to produce emergent and highly differentiated topological arrangements that negotiate the specific relationships among a desired maximal mesh density, geometric patterning, and equalized force distribution.
Research suggests that personality traits have both direct and indirect effects on the development of psychological symptoms, with indirect effects mediated by stressful or traumatic events. This study models the direct influence of personality traits on residualized changes in internalizing and externalizing symptoms following a stressful and potentially traumatic deployment, as well as the indirect influence of personality on symptom levels mediated by combat exposure.
We utilized structural equation modeling with a longitudinal prospective study of 522 US National Guard soldiers deployed to Iraq. Analyses were based on self-report measures of personality, combat exposure, and internalizing and externalizing symptoms.
Both pre-deployment Disconstraint and externalizing symptoms predicted combat exposure, which in turn predicted internalizing and externalizing symptoms. There was a significant indirect effect for pre-deployment externalizing symptoms on post-deployment externalizing via combat exposure (p < 0.01). Negative Emotionality and pre-deployment internalizing symptoms directly predicted post-deployment internalizing symptoms, but both were unrelated to combat exposure. No direct effects of personality on residualized changes in externalizing symptoms were found.
Baseline symptom dimensions had significant direct and indirect effects on post-deployment symptoms. Controlling for both pre-exposure personality and symptoms, combat experiences remained positively related to both internalizing and externalizing symptoms. Implications for diagnostic classification are discussed.