julilili42/papers huggingface dataset:
Real-Time Adaptive Microstimulation Increases Reliability of Electrically Evoked Cortical Potentials
2011-01-21

Cortical neuroprostheses that employ repeated electrical stimulation of cortical areas with fixed stimulus parameters, are faced with the problem of large trial-by-trial variability of evoked potentials. This variability is caused by the ongoing cortical signal processing, but it is an unwanted phenomenon if one aims at imprinting neural activity as precisely as possible. Here, we use local field potentials measured by one microelectrode, located at a distance of 200 microns from the stimulation site, to drive the electrically evoked potential toward a desired target potential by real-time adaptation of the stimulus intensity. The functional relationship between ongoing cortical activity, evoked potential, and stimulus intensity was estimated by standard machine learning techniques (support vector regression with problem-specific kernel function) from a set of stimulation trials with randomly varied stimulus intensities. The smallest deviation from the target potential was achieved for low stimulus intensities. Further, the observed precision effect proved time sensitive, since it was abolished by introducing a delay between data acquisition and stimulation. These results indicate that local field potentials contain sufficient information about ongoing local signal processing to stabilize electrically evoked potentials. We anticipate that adaptive low intensity microstimulation will play an important role in future cortical prosthetic devices that aim at restoring lost sensory functions.
Bio-magnetic signatures of fetal breathing movement
2011-01-21

The purpose of fetal magnetoencephalography (fMEG) is to record and analyze fetal brain activity. Unavoidably, these recordings consist of a complex mixture of bio-magnetic signals from both mother and fetus. The acquired data include biological signals that are related to maternal and fetal heart function as well as fetal gross body and breathing movements. Since fetal breathing generates a significant source of bio-magnetic interference during these recordings, the goal of this study was to identify and quantify the signatures pertaining to fetal breathing movements (FBM). The fMEG signals were captured using superconducting quantum interference devices (SQUIDs) The existence of FBM was verified and recorded concurrently by an ultrasound-based video technique. This simultaneous recording is challenging since SQUIDs are extremely sensitive to magnetic signals and highly susceptible to interference from electronic equipment. For each recording, an ultrasound-FBM (UFBM) signal was extracted by tracing the displacement of the boundary defined by the fetal thorax frame by frame. The start of each FBM was identified by using the peak points of the UFBM signal. The bio-magnetic signals associated with FBM were obtained by averaging the bio-magnetic signals time locked to the FBMs. The results showed the existence of a distinctive sinusoidal signal pattern of FBM in fMEG data.
Distinct profile of the mitochondrial DNA common deletion in benign skin lesions
2011-01-21

Abstract: Mutations of mitochondrial (mt) DNA, particularly the 4977 bp long common deletion, are increased in aging tissues and preferentially found in chronologically and photoaged skin. Mutations of human mitochondrial DNA (mtDNA) have also been identified in malignant tumors of the skin and of other organs. However, benign skin lesions have not yet been investigated. We analyzed the frequency of the common deletion in 27 benign skin lesions [8 seborrheic keratoses (SK), 5 epidermal nevi (EN), 14 solar lentigos (SL)] by quantitative real‐time PCR, because SK and especially SL have been related to (photo)aged skin. All SK and four of five EN displayed reduced common deletion levels compared with adjacent normal skin. In contrast, 50% of SL revealed a higher percentage of the common deletion than the adjacent normal skin, and some SL showed very high absolute common deletion levels up to 14% of total mtDNA. Our results show that the amount of the common deletion is significantly different in benign skin lesions and raise further questions regarding the pathogenesis of SL and its possible role as a precursor lesion of SK.
24-Hour intraocular pressure phasing remains an important tool in glaucoma diagnostics
2011-01-21

We read with great interest the article by Moodie et al 1 questioning the importance of intraocular pressure (IOP) phasing outside office hours. IOP is the most important, treatable risk factor with regard to manifestation and progression of glaucoma. There is increasing evidence for the importance of IOP fluctuations in addition to its absolute level (overview in Sultan et al 2). In our opinion, the chosen study design cannot exclude a relevant bias as the subgroups were allocated by various physicians using non-standardised criteria. The sample size is comparatively small: 76 glaucoma patients of which a subgroup of only 41 patients was assigned for 24 h IOP phasing. Furthermore, the total number of glaucoma patients examined over the study period ...
Aquifer analogs as a tool for improved site characterization in groundwater remediation projects
2011-01-21

The lack of information about true aquifer heterogeneities represents a challenge for a complete understanding of the transport and fate of groundwater contaminants. Due to practical constraints, conceptual site models based on the commonly used investigation methods do not precisely depict aquifer heterogeneities, which decisively affect the spreading of contaminants and the success of clean-up projects. A high-resolution aquifer analog of one of the most important groundwater reservoirs in Central Europe is used to help investigate the effects of realistic multi-scale physical and chemical heterogeneities on the fate of a common organic contaminant. The results of this study provide an integral understanding of subsurface contaminant transport while taking into consideration the local environmental conditions, and demonstrating how simplified assumptions can prevent the use of mathematical models for correct predictions.
A fast brassinolide‐regulated response pathway in the plasma membrane of Arabidopsis thaliana
2011-01-22

Summary To understand molecular processes in living plant cells, quantitative spectro‐microscopic technologies are required. By combining fluorescence lifetime spectroscopy with confocal microscopy, we studied the subcellular properties and function of a GFP‐tagged variant of the plasma membrane‐bound brassinosteroid receptor BRI1 (BRI1–GFP) in living cells of Arabidopsis seedlings. Shortly after adding brassinolide, we observed BRI1‐dependent cell‐wall expansion, preceding cell elongation. In parallel, the fluorescence lifetime of BRI1–GFP decreased, indicating an alteration in the receptor’s physico‐chemical environment. The parameter modulating the fluorescence lifetime of BRI1–GFP was found to be BL‐induced hyperpolarization of the plasma membrane. Furthermore, for induction of hyperpolarization and cell‐wall expansion, activation of the plasma membrane P‐ATPase was necessary. This activation required BRI1 kinase activity, and was mediated by BL‐modulated interaction of BRI1 with the P‐ATPase. Our results were used to develop a model suggesting that there is a fast BL‐regulated signal response pathway within the plasma membrane that links BRI1 with P‐ATPase for the regulation of cell‐wall expansion.
The MreB-Like Protein Mbl ofStreptomyces coelicolorA3(2) Depends on MreB for Proper Localization and Contributes to Spore Wall Synthesis
2011-01-22

ABSTRACT Most bacteria with a rod-shaped morphology contain an actin-like cytoskeleton consisting of MreB polymers, which form helical spirals underneath the cytoplasmic membrane to direct peptidoglycan synthesis for the elongation of the cell wall. In contrast, MreB of Streptomyces coelicolor is not required for vegetative growth but has a role in sporulation. Besides MreB, S. coelicolor encodes two further MreB-like proteins, Mbl and SCO6166, whose function is unknown. Whereas MreB and Mbl are highly similar, SCO6166 is shorter, lacking the subdomains IB and IIB of actin-like proteins. Here, we showed that MreB and Mbl are not functionally redundant but cooperate in spore wall synthesis. Expression analysis by semiquantitative reverse transcription-PCR revealed distinct expression patterns. mreB and mbl are induced predominantly during morphological differentiation. In contrast, sco6166 is strongly expressed during vegetative growth but switched off during sporulation. All genes could be deleted without affecting viability. Even a Δ mreB Δ mbl double mutant was viable. Δ sco6166 had a wild-type phenotype. Δ mreB , Δ mbl , and Δ mreB Δ mbl produced swollen, prematurely germinating spores that were sensitive to various kinds of stress, suggesting a defect in spore wall integrity. During aerial mycelium formation, an Mbl-mCherry fusion protein colocalized with an MreB-enhanced green fluorescent protein (MreB-eGFP) fusion protein at the sporulation septa. Whereas MreB-eGFP localized properly in the Δ mbl mutant, Mbl-mCherry localization depended on the presence of a functional MreB protein. Our results revealed that MreB and Mbl cooperate in the synthesis of the thickened spore wall, while SCO6166 has a nonessential function during vegetative growth.
Impairment in Proverb Interpretation as an Executive Function Deficit in Patients with Amnestic Mild Cognitive Impairment and Early Alzheimer’s Disease
2011-01-22

&lt;i&gt;Background/Aims:&lt;/i&gt; Proverb interpretation is assumed to reflect executive functions. We hypothesized that proverb interpretation is impaired in patients with amnestic mild cognitive impairment (aMCI) diagnosed as single-domain impairment by common neuropsychological testing. &lt;i&gt;Methods:&lt;/i&gt; We compared performance in a proverb interpretation test in single-domain aMCI patients and patients with early Alzheimer’s disease (EAD). &lt;i&gt;Results:&lt;/i&gt; The groups with aMCI and EAD performed significantly worse than healthy controls. Both patient groups gave concrete answers with a similar frequency. However, patients with EAD tended to give senseless answers more frequently. &lt;i&gt;Conclusions:&lt;/i&gt; Our data suggest that in patients diagnosed as single-domain aMCI, deterioration of executive functions is detectable with subtle and appropriate neuropsychological testing. Implementation of these procedures may improve the early prediction of AD.
It Takes Two–Skilled Recognition of Objects Engages Lateral Areas in Both Hemispheres
2011-01-24

Our object recognition abilities, a direct product of our experience with objects, are fine-tuned to perfection. Left temporal and lateral areas along the dorsal, action related stream, as well as left infero-temporal areas along the ventral, object related stream are engaged in object recognition. Here we show that expertise modulates the activity of dorsal areas in the recognition of man-made objects with clearly specified functions. Expert chess players were faster than chess novices in identifying chess objects and their functional relations. Experts' advantage was domain-specific as there were no differences between groups in a control task featuring geometrical shapes. The pattern of eye movements supported the notion that experts' extensive knowledge about domain objects and their functions enabled superior recognition even when experts were not directly fixating the objects of interest. Functional magnetic resonance imaging (fMRI) related exclusively the areas along the dorsal stream to chess specific object recognition. Besides the commonly involved left temporal and parietal lateral brain areas, we found that only in experts homologous areas on the right hemisphere were also engaged in chess specific object recognition. Based on these results, we discuss whether skilled object recognition does not only involve a more efficient version of the processes found in non-skilled recognition, but also qualitatively different cognitive processes which engage additional brain areas.
Changes in upper airway width associated with Class II treatments (headgear vs activator) and different growth patterns
2011-01-24

Abstract Objective: To investigate the upper airways for anteroposterior width against different growth patterns and for alterations during various Class II treatments. Materials and Methods: Cephalograms from three treatment groups (headgear, activator, and bite-jumping appliance) were evaluated by a single investigator at baseline and at the end of orthodontic treatment. Cephalograms were used to determine upper airway width at different levels in the anteroposterior plane. Patients in the headgear group were additionally divided into six subsets on the basis of y-axis values to assess the influence of different growth patterns. Results: Small increases in pharyngeal width were noted at all vertical level segments, both at baseline and during orthodontic treatments. No significant differences in these small increases were noted across various treatment modalities and growth patterns. Conclusion: Upper airway changes did not significantly vary with the different treatment modalities investigated in the present study. Nevertheless, reductions in pharyngeal width potentially triggering or exacerbating obstructive sleep apnea syndrome (OSAS) are always possible in the headgear phase.
Apelin Serum Levels are not Associated with Early Atherosclerosis or Fat Distribution in Young Subjects with Increased Risk for Type 2 Diabetes
2011-01-24

Apelin is proposed to possess protective cardiovascular properties and may furthermore promote favorable effects on glucose metabolism. First data in humans seem to support this hypothesis. Therefore we aimed to assess the meaning of apelin as an early risk indicator in young subjects prone to atherosclerosis and type 2 diabetes. Furthermore we examined the association of apelin serum levels with insulin sensitivity/resistance and body fat distribution as probably dependent cardiovascular risk factors. We examined 344 individuals (f/m=216/128, mean age 46±1 years) with an increased risk for type 2 diabetes. Apelin-36 serum levels were measured via ELISA. Endothelial dysfunction and intima media thickness (IMT) were assessed using high resolution ultrasound. Visceral adipose tissue (VAT) was measured with an axial T1-weighted fast spin echo technique with a 1.5 T whole-body imager. According to the study population's age, FMD (6.4±0.2%) and IMT (0.56±0.01 mm) were within the expected ranges. Gender or age had no influence on serum apelin levels. When looked at early stages of atherosclerosis, we could not detect a significant correlation between apelin serum levels and FMD or IMT. Blood pressure as well was unaffected by serum apelin levels. Furthermore, neither parameters of insulin sensitivity like insulin sensitivity index (ISI), nor fat distribution like BMI, grade of adiposity, total adipose tissue or VAT were associated with apelin serum levels. We conclude that apelin serum levels do not add further information on the cardiovascular-, or diabetes risk pattern in a diabetes prone population.
Factors associated with time delay to carotid stenting in patients with a symptomatic carotid artery stenosis
2011-01-24

Treatment of a symptomatic stenosis is known to be most beneficial within 14 days after the presenting event but this can frequently not be achieved in daily practice. The aim of this study was the assessment of factors responsible for this time delay to treatment. A retrospective analysis of a prospective two-center CAS database was carried out to investigate the potential factors that influence a delayed CAS treatment. Of 374 patients with a symptomatic carotid stenosis, 59.1% were treated beyond ≥14 days. A retinal TIA event (OR = 3.59, 95% CI 1.47-8.74, p < 0.01) was found to be a predictor for a delayed treatment, whereas the year of the intervention (OR = 0.32, 95% CI 0.20-0.50, p < 0.01) and a contralateral carotid occlusion (OR = 0.42, 95% CI 0.21-0.86, p = 0.02) were predictive of an early treatment. Similarly, within the subgroup of patients with transient symptoms, the year of the intervention (OR = 0.28, 95% CI 0.14-0.59, p < 0.01) was associated with an early treatment, whereas a retinal TIA as the qualifying event (OR = 6.96, 95% CI 2.37-20.47, p < 0.01) was associated with a delayed treatment. Treatment delay was most pronounced in patients with an amaurosis fugax, whereas a contralateral carotid occlusion led to an early intervention. Although CAS is increasingly performed faster in the last years, there is still scope for an even more accelerated treatment strategy, which might prevent future recurrent strokes prior to treatment.
Analyzing learner language: towards a flexible natural language processing architecture for intelligent language tutors
2011-01-25

Abstract Intelligent language tutoring systems (ILTS) typically analyze learner input to diagnose learner language properties and provide individualized feedback. Despite a long history of ILTS research, such systems are virtually absent from real-life foreign language teaching (FLT). Taking a step toward more closely linking ILTS research to real-life FLT, in this article we investigate the connection between FLT activity design and the system architecture of an ILT system. We argue that a demand-driven, annotation-based natural language processing (NLP) architecture is well-suited to handle the demands posed by the heterogeneous learner input which results when supporting a wider range of FLT activity types. We illustrate how the unstructured information management architecture (UIMA) can be used in an ILTS, thereby connecting the specific needs of activities in foreign language teaching to the current research and development of NLP architectures in general. Making the conceptual issues concrete, we discuss the design and realization of a UIMA-based reimplementation of the NLP in the TAGARELA system, an intelligent web-based tutoring system supporting the teaching and learning of Portuguese. Keywords: intelligent language tutoring systems (ILTS); intelligent computer-assisted language learning (ICALL); natural language processing (NLP); unstructured information management architecture (UIMA); demand-driven annotation-based architecture; individualized feedback Notes 1. See, e.g., the error taxonomy for the BRIDGE system in Weinberg, Garman, Martin, and Merlo (1995), or the one for the ALICE-chan system in Levin and Evans (1995).
Quasinormal modes, scattering, and Hawking radiation of Kerr-Newman black holes in a magnetic field
2011-01-26

We perform a comprehensive analysis of the spectrum of proper oscillations\\n(quasinormal modes), transmission/reflection coefficients and Hawking radiation\\nfor a massive charged scalar field in the background of the Kerr-Newman black\\nhole immersed in an asymptotically homogeneous magnetic field. There are two\\nmain effects: the Zeeman shift of the particle energy in the magnetic field and\\nthe difference of values of an electromagnetic potential between the horizon\\nand infinity, i.e. the Faraday induction. We have shown that "turning on" the\\nmagnetic field induces a stronger energy-emission rate and leads to\\n"recharging" of the black hole. Thus, a black hole immersed in a magnetic field\\nevaporates much quicker, achieving thereby an extremal state in a shorter\\nperiod of time. Quasinormal modes are moderately affected by the presence of a\\nmagnetic field which is assumed to be relatively small compared to the\\ngravitational field of the black hole.\\n
Visual Stability and the Motion Aftereffect: A Psychophysical Study Revealing Spatial Updating
2011-01-26

Eye movements create an ever-changing image of the world on the retina. In particular, frequent saccades call for a compensatory mechanism to transform the changing visual information into a stable percept. To this end, the brain presumably uses internal copies of motor commands. Electrophysiological recordings of visual neurons in the primate lateral intraparietal cortex, the frontal eye fields, and the superior colliculus suggest that the receptive fields (RFs) of special neurons shift towards their post-saccadic positions before the onset of a saccade. However, the perceptual consequences of these shifts remain controversial. We wanted to test in humans whether a remapping of motion adaptation occurs in visual perception.The motion aftereffect (MAE) occurs after viewing of a moving stimulus as an apparent movement to the opposite direction. We designed a saccade paradigm suitable for revealing pre-saccadic remapping of the MAE. Indeed, a transfer of motion adaptation from pre-saccadic to post-saccadic position could be observed when subjects prepared saccades. In the remapping condition, the strength of the MAE was comparable to the effect measured in a control condition (33±7% vs. 27±4%). Contrary, after a saccade or without saccade planning, the MAE was weak or absent when adaptation and test stimulus were located at different retinal locations, i.e. the effect was clearly retinotopic. Regarding visual cognition, our study reveals for the first time predictive remapping of the MAE but no spatiotopic transfer across saccades. Since the cortical sites involved in motion adaptation in primates are most likely the primary visual cortex and the middle temporal area (MT/V5) corresponding to human MT, our results suggest that pre-saccadic remapping extends to these areas, which have been associated with strict retinotopy and therefore with classical RF organization. The pre-saccadic transfer of visual features demonstrated here may be a crucial determinant for a stable percept despite saccades.
Excitation Isotropy of Single CdSe/ZnS Nanocrystals
2011-01-27

We study the dimensionality of the excitation transition dipole moment for single CdSe/ZnS core-shell nanocrystals using azimuthally and radially polarized laser modes. The comparison of measured and simulated single nanocrystal excitation patterns shows that single CdSe/ZnS quantum dots possess a spherically degenerated excitation transition dipole. We show that the dimensionality of the excitation transition dipole moment distribution is the same for all individual CdSe/ZnS nanocrystals, disregarding the difference in core size and irrespective of variations in the local environment. In contrast to the emission transition dipole moment, which is oriented in one plane, the excitation transition dipole moment of a single CdSe/ZnS quantum dots possesses an isotropy in three dimensions.
Training to improve reading speed in patients with juvenile macular dystrophy: a randomized study comparing two training methods
2011-01-27

Although the median effect of both training methods was limited, individual patients benefited well. Our results may indicate a difference in the training effect between both methods on the reading strategy: the RSVP method reduces fixation duration, the SM method decreases the number of forward saccades. Patients can apply their newly learned reading strategy in the natural reading situation, e.g. in page reading without special presentation of the text. These results can be used as a basis for further improvement in training methods for optimizing reading performance in patients with a central scotoma.
Expression of the embryonic stem cell marker SOX2 in early-stage breast carcinoma
2011-01-28

In this report, we show that the embryonic stem cell factor SOX2 is expressed in a variety of early stage postmenopausal breast carcinomas and metastatic lymph nodes. Our data suggest that SOX2 plays an early role in breast carcinogenesis and high expression may promote metastatic potential. Further studies are needed to explore whether SOX2 can predict metastatic potential at an early tumor stage.