julilili42/papers huggingface dataset:
Comparison between High-Resolution CT and MRI Using a Very Short Echo Time in Patients with Cystic Fibrosis with Extra Focus on Mosaic Attenuation
2012-11-27

&lt;b&gt;&lt;i&gt;Background:&lt;/i&gt;&lt;/b&gt; It would be beneficial to establish pulmonary MRI as a complementary approach to CT for direct visualization of mosaic perfusion, bullae, and emphysema in patients with cystic fibrosis. &lt;b&gt;&lt;i&gt;Objectives:&lt;/i&gt;&lt;/b&gt; The purpose of this study was to compare both modalities, CT and MRI, using the Helbich-Bhalla score with a special focus on reliable detection of a mosaic pattern. &lt;b&gt;&lt;i&gt;Methods:&lt;/i&gt;&lt;/b&gt; Out of 51 patients examined by MRI on a 1.5-Tesla system during a period of 2 years, 19 patients were scheduled for additional low-dose CT in a clinical context. The MRI protocol comprised a gradient echo (GRE) sequence with a very short echo time (TE = 0.8 ms) in inspiration and expiration, a 3-D GRE sequence in breath hold, and a fast spin echo sequence with respiration and ECG triggering. MDCT was carried out in inspiration and adapted to body weight using 100 or 120 kV, 30-60 mA, 1- and 3-mm slice thicknesses, as well as low and high kernels. Additionally incremental slices in 3 positions were recorded in expiration for distinct detection of air trapping. CT and MRI analyses were performed by two radiologic readers in consensus unaware of the clinical parameters. The Helbich-Bhalla score of both examinations was correlated. Mean difference and accordance were assessed in each category. &lt;b&gt;&lt;i&gt;Results:&lt;/i&gt;&lt;/b&gt; There was a strong correlation between CT and MRI (R = 0.87, p &lt; 0.01). The mean Helbich-Bhalla score for CT was 12.2 (range 1-18) and for MRI it was 11.7 (range 2-19). The mean difference was 0.5 points. Besides this strong correlation for findings (bronchiectasis, mucus plugging, peribronchial thickening, and consolidation) with a prolonged T2 TE in MRI, we could also state a qualitative agreement of 95-100% in the categories with short T2 and low signal intensity in MRI as emphysema, bullae, and mosaic perfusion. &lt;b&gt;&lt;i&gt;Conclusions:&lt;/i&gt;&lt;/b&gt; These results suggest that in our patient group none of the relevant findings were missed by MR imaging and reading.
The New Carbodiimide Li2Gd2Sr(CN2)5 Having a Crystal Structure Related to That of Gd2(CN2)3
2012-11-27

Abstract The new carbodiimide compounds Li 2 RE 2 Sr(CN 2 ) 5 ( RE = Sm, Gd, Eu, Tb) were prepared by a straight forward solid state metathesis reaction of RE F 3 , SrF 2 , and Li 2 (CN 2 ) at around 600 °C. The crystal structure of Li 2 Gd 2 Sr(CN 2 ) 5 was solved based on X‐ray single‐crystal diffraction data. Corresponding Li 2 RE 2 Sr(CN 2 ) 5 compounds were analyzed by isotypic indexing of their powder patterns. The crystal structure of Li 2 Gd 2 Sr(CN 2 ) 5 can be well related to that of Gd 2 (CN 2 ) 3 , because both structures are based on layered structures composed of close packed layers of [N=C=N] 2– sticks, alternating with layers of metal ions. The crystal structure of Li 2 Gd 2 Sr(CN 2 ) 5 can be considered to contain an ABC layer sequence of [N = C=N] 2– layers with the interlayer voids being occupied by (three) distinct types of cations.
Repetitive Magnetic Stimulation Induces Functional and Structural Plasticity of Excitatory Postsynapses in Mouse Organotypic Hippocampal Slice Cultures
2012-11-28

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation technique that can alter cortical excitability in human subjects for hours beyond the stimulation period. It thus has potential as a therapeutic tool in neuropsychiatric disorders associated with alterations in cortical excitability. However, rTMS-induced neural plasticity remains insufficiently understood at the cellular level. To learn more about the effects of repetitive magnetic stimulation (rMS), we established an in vitro model of rMS using mouse organotypic entorhino-hippocampal slice cultures. We assessed the outcome of a high-frequency (10 Hz) rMS protocol on functional and structural properties of excitatory synapses in mature hippocampal CA1 pyramidal neurons. Whole-cell patch-clamp recordings, immunohistochemistry, and time-lapse imaging techniques revealed that rMS induces a long-lasting increase in glutamatergic synaptic strength, which is accompanied by structural remodeling of dendritic spines. The effects of rMS on spine size were predominantly seen in small spines, suggesting differential effects of rMS on subpopulations of spines. Furthermore, our data indicate that rMS-induced postsynaptic changes depend on the NMDA receptor-mediated accumulation of GluA1-containing AMPA receptors. These results provide first experimental evidence that rMS induces coordinated functional and structural plasticity of excitatory postsynapses, which is consistent with a long-term potentiation of synaptic transmission.
Channel Noise from Both Slow Adaptation Currents and Fast Currents Is Required to Explain Spike-Response Variability in a Sensory Neuron
2012-11-28

Spike-timing variability has a large effect on neural information processing. However, for many systems little is known about the noise sources causing the spike-response variability. Here we investigate potential sources of spike-response variability in auditory receptor neurons of locusts, a classic insect model system. At low-spike frequencies, our data show negative interspike-interval (ISI) correlations and ISI distributions that match the inverse Gaussian distribution. These findings can be explained by a white-noise source that interacts with an adaptation current. At higher spike frequencies, more strongly peaked distributions and positive ISI correlations appear, as expected from a canonical model of suprathreshold firing driven by temporally correlated (i.e., colored) noise. Simulations of a minimal conductance-based model of the auditory receptor neuron with stochastic ion channels exclude the delayed rectifier as a possible noise source. Our analysis suggests channel noise from an adaptation current and the receptor or sodium current as main sources for the colored and white noise, respectively. By comparing the ISI statistics with generic models, we find strong evidence for two distinct noise sources. Our approach does not involve any dendritic or somatic recordings that may harm the delicate workings of many sensory systems. It could be applied to various other types of neurons, in which channel noise dominates the fluctuations that shape the neuron's spike statistics.
Yersinia pestis: New Evidence for an Old Infection
2012-11-28

The successful reconstruction of an ancient bacterial genome from archaeological material presents an important methodological advancement for infectious disease research. The reliability of evolutionary histories inferred by the incorporation of ancient data, however, are highly contingent upon the level of genetic diversity represented in modern genomic sequences that are publicly accessible, and the paucity of available complete genomes restricts the level of phylogenetic resolution that can be obtained. Here we add to our original analysis of the Yersinia pestis strain implicated in the Black Death by consolidating our dataset for 18 modern genomes with single nucleotide polymorphism (SNP) data for an additional 289 strains at over 600 positions. The inclusion of this additional data reveals a cluster of Y. pestis strains that diverge at a time significantly in advance of the Black Death, with divergence dates roughly coincident with the Plague of Justinian (6(th) to 8(th) century AD). In addition, the analysis reveals further clues regarding potential radiation events that occurred immediately preceding the Black Death, and the legacy it may have left in modern Y. pestis populations. This work reiterates the need for more publicly available complete genomes, both modern and ancient, to achieve an accurate understanding of the history of this bacterium.
Differents, discriminants and Steinitz classes
2012-11-28

Let L|K be an extension of algebraic number fields. By a theorem of Hecke, the ideal class of the different 픇L|K is a square in ClL. Whereas the class of the discriminant 픡L|K=NL|K(픇L|K) is the square of the Steinitz class sL|K in ClK, which vanishes if and only if the ring RL of integers in L is a free module over RK, there is no distinguished square root for the different in general. In an attempt to give some interpretation for Hecke's theorem, we examine when there is r∈ClL such that r2=[픇L|K] and NL|K(r)=sL|K (‘Steinitz root’). In this case, every ideal of L in the class r−1 is a free RK-module.
The Stringent Response of Staphylococcus aureus and Its Impact on Survival after Phagocytosis through the Induction of Intracellular PSMs Expression
2012-11-29

The stringent response is initiated by rapid (p)ppGpp synthesis, which leads to a profound reprogramming of gene expression in most bacteria. The stringent phenotype seems to be species specific and may be mediated by fundamentally different molecular mechanisms. In Staphylococcus aureus, (p)ppGpp synthesis upon amino acid deprivation is achieved through the synthase domain of the bifunctional enzyme RSH (RelA/SpoT homolog). In several firmicutes, a direct link between stringent response and the CodY regulon was proposed. Wild-type strain HG001, rsh(Syn), codY and rsh(Syn), codY double mutants were analyzed by transcriptome analysis to delineate different consequences of RSH-dependent (p)ppGpp synthesis after induction of the stringent response by amino-acid deprivation. Under these conditions genes coding for major components of the protein synthesis machinery and nucleotide metabolism were down-regulated only in rsh positive strains. Genes which became activated upon (p)ppGpp induction are mostly regulated indirectly via de-repression of the GTP-responsive repressor CodY. Only seven genes, including those coding for the cytotoxic phenol-soluble modulins (PSMs), were found to be up-regulated via RSH independently of CodY. qtRT-PCR analyses of hallmark genes of the stringent response indicate that an RSH activating stringent condition is induced after uptake of S. aureus in human polymorphonuclear neutrophils (PMNs). The RSH activity in turn is crucial for intracellular expression of psms. Accordingly, rsh(Syn) and rsh(Syn), codY mutants were less able to survive after phagocytosis similar to psm mutants. Intraphagosomal induction of psmα1-4 and/or psmβ1,2 could complement the survival of the rsh(Syn) mutant. Thus, an active RSH synthase is required for intracellular psm expression which contributes to survival after phagocytosis.
Change mechanisms in psychotherapy: Multiperspective assessment and relation to outcome
2012-11-29

The study aimed at constructing a reliable and valid post-session questionnaire measuring general change mechanisms of psychotherapy with correspondent versions for patient and therapist perspectives. Therefore, 253 inpatients in early, middle, and late stages of psychotherapy completed the newly developed Scale for the Multiperspective Assessment of General Change Mechanisms in Psychotherapy (SACiP) and diverse outcome measures. The psychometric qualities of the SACiP were excellent as shown by (a) exploratory factor analyses on patient and therapist ratings, (b) confirmatory factor analyses on later measuring times, and (c) high internal consistencies. Supporting construct validity, the SACiP predicted outcome, as shown by correlational analyses and mixed effects modeling. Patient evaluations of change mechanisms were better predictors of outcome than the corresponding therapist evaluations.
Spastic Paraplegia Mutation N256S in the Neuronal Microtubule Motor KIF5A Disrupts Axonal Transport in a Drosophila HSP Model
2012-11-29

Hereditary spastic paraplegias (HSPs) comprise a group of genetically heterogeneous neurodegenerative disorders characterized by spastic weakness of the lower extremities. We have generated a Drosophila model for HSP type 10 (SPG10), caused by mutations in KIF5A. KIF5A encodes the heavy chain of kinesin-1, a neuronal microtubule motor. Our results imply that SPG10 is not caused by haploinsufficiency but by the loss of endogenous kinesin-1 function due to a selective dominant-negative action of mutant KIF5A on kinesin-1 complexes. We have not found any evidence for an additional, more generalized toxicity of mutant Kinesin heavy chain (Khc) or the affected kinesin-1 complexes. Ectopic expression of Drosophila Khc carrying a human SPG10-associated mutation (N256S) is sufficient to disturb axonal transport and to induce motoneuron disease in Drosophila. Neurofilaments, which have been recently implicated in SPG10 disease manifestation, are absent in arthropods. Impairments in the transport of kinesin-1 cargos different from neurofilaments are thus sufficient to cause HSP-like pathological changes such as axonal swellings, altered structure and function of synapses, behavioral deficits, and increased mortality.
Partial loss of contractile marker proteins in human testicular peritubular cells in infertility patients
2012-11-29

Summary Fibrotic remodelling of the testicular tubular wall is common in human male infertility caused by impaired spermatogenesis. We hypothesized that this morphological change bears witness of an underlying fundamentally altered state of the cells building this wall, that is, peritubular smooth muscle‐like cells. This could include a loss of the contractile abilities of these cells and thus be a factor in male infertility. Immune cells are increased in the tubular wall in these cases, hence local immune cell‐related factors, including a prostaglandin (PG) metabolite may be involved. To explore these points in the human, we used testicular biopsies, in which tubules with normal spermatogenesis and impaired spermatogenesis are next to each other [mixed atrophy (MA)], normal biopsies and cultured human testicular peritubular cells. Proteins essential for contraction, myosin heavy chain (MYH11), calponin (Cal) and relaxation, cGMP ‐dependent protein kinase 1 ( cGKI ), were readily detected by immunohistochemistry and were equally distributed in all peritubular cells of biopsies with normal spermatogenesis. In all biopsies, vascular smooth muscle cells also stained and served as important intrinsic controls, which showed that in MA samples when spermatogenesis was impaired, staining was restricted to only few peritubular cells or was absent. When spermatogenesis was normal, regular peritubular staining became obvious. This pattern suggests complex regulatory influences, which in face of the identical systemic hormonal situation in MA patients, are likely caused by the local testicular micromilieu. The PG metabolite 15dPGJ2 may represent such a factor and it reduced Cal protein levels in peritubular cells from patients with/without impaired spermatogenesis. The documented phenotypic switch of peritubular, smooth muscle‐like cells in MA patients may impair the abilities of the afflicted seminiferous tubules to contract and relax and must now be considered as a part of the complex events in male infertility.
Simulation of the chromatographic separation process in HPLC employing suspended‐state NMR spectroscopy – comparison of interaction behavior for monomeric and hydride‐modified C18 stationary phases
2012-11-29

The interactions of different analytes with monomeric and hydride‐modified stationary phases have been investigated employing suspended‐state NMR spectroscopy. The suspended‐state high‐resolution/magic‐angle‐spinning 1 H‐NMR spectrum of an analyte in the presence of C 18 SP material shows a splitting into two sets of signals for the analyte molecule. One state reflects a closer interaction between analyte and C 18 ‐modified surface that results in an upfield shift and broader signal half‐widths. This phenomenon suggests that the analyte exists in two environments. We report a systematic approach upon the investigation on the interaction in the interface of analyte, mobile phase, and modified silica through synthesis of differently modified silica with a gradual increase in surface coverage. The determination of the signal half‐widths and chemical shifts revealed a relationship between the modification technique of the C 18 SP s and the chromatographic and NMR spectroscopic behavior. Increasing ligand density results in higher shielding of the NMR signals for the analyte in the “adsorbed” state. The measurement of spin‐lattice relaxation times T 1 of the analyte molecule correlate NMR parameter together with separation behavior in HPLC . Furthermore, suspended‐state and solid‐state NMR measurements revealed different alkyl chain mobilities for the monomeric and hydride‐modified SP s.
Correction: Human Cytomegalovirus Entry into Dendritic Cells Occurs via a Macropinocytosis-Like Pathway in a pH-Independent and Cholesterol-Dependent Manner
2012-11-29

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that is able to infect fibroblastic, epithelial, endothelial and hematopoietic cells.Over the past ten years, several groups have provided direct evidence that dendritic cells (DCs) fully support the HCMV lytic cycle.We previously demonstrated that the C-type lectin dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) has a prominent role in the docking of HCMV on monocyte-derived DCs (MDDCs).The DC-SIGN/HCMV interaction was demonstrated to be a crucial and early event that substantially enhanced infection in trans, i.e., from one CMV-bearing cell to another non-infected cell (or trans-infection), and rendered susceptible cells fully permissive to HCMV infection.Nevertheless, nothing is yet known about how HCMV enters MDDCs.In this study, we demonstrated that VHL/E HCMV virions (an endothelio/dendrotropic strain) are first internalized into MDDCs by a macropinocytosis-like process in an actin-and cholesterol-dependent, but pH-independent, manner.We observed the accumulation of virions in large uncoated vesicles with endosomal features, and the virions remained as intact particles that retained infectious potential for several hours.This trans-infection property was specific to MDDCs because monocytederived macrophages or monocytes from the same donor were unable to allow the accumulation of and the subsequent transmission of the virus.Together, these data allowed us to delineate the early mechanisms of the internalization and entry of an endothelio/dendrotropic HCMV strain into human MDDCs and to propose that DCs can serve as a ''Trojan horse'' to convey CMV from entry sites to other locations that may favor the occurrence of either latency or acute infection.
Domain decomposition strategies for the stochastic heat equation
2012-11-29

Abstract We consider the numerical approximation of mild solutions of the stochastic, Hilbert space-valued heat equation with a uniformly elliptic operator A:D(A)→L 2(D) and a symmetric operator Q:L 2(D)→L 2(D) with finite trace. We apply different domain decomposition algorithms based on explicit and implicit time-stepping, together with a finite element and backward Euler discretization to solve the problem, and derive optimal strong and weak rates of convergence. For this purpose, and due to the interplay of limited regularity in time of the driving noise and the splitting character of the scheme, a well-known deterministic domain decomposition algorithm requires modifications to prove an optimal weak rate of convergence. Keywords: weak orderstrong orderstochastic heat equationfinite elementEuler schemedomain decomposition2010 AMS Subject Classifications: 60H1565M5565M6065M15
The Long-Time Low-Temperature Degradation (“LTD”) Kinetics in 3Y-TZP Bioceramics
2012-11-29

This work follows a study on hydrothermal aged 3Y-TZP bioceramics, which showed that the surface X-ray diffraction data from moisture exposed samples give distorted results, reflecting a simple linear growth of a partially transformed layer from the surface into the interior. There is no indication for a leveling off or retardation of this growth at elevated temperatures (134°C) and here we present evidence that this is probably true at body temperatures as well. However, the rate constants at body temperature for the studied material are low and indicate a long lifetime. It should be noted that this statement is specific and other materials with minor changes to chemistry or microstructure may behave much better or much worse under those conditions. Furthermore slow crack growth and crack interactions are not yet investigated and may necessitate a minimum of low-temperature degradation susceptibility to ensure reliable long-time use.
Natively Inhibited Trypanosoma brucei Cathepsin B Structure Determined by Using an X-ray Laser
2012-11-30

Diffraction Before Destruction A bottleneck in x-ray crystallography is the growth of well-ordered crystals large enough to obtain high-resolution diffraction data within an exposure that limits radiation damage. Serial femtosecond crystallography promises to overcome these constraints by using short intense pulses that out-run radiation damage. A stream of crystals is flowed across the free-electron beam and for each pulse, diffraction data is recorded from a single crystal before it is destroyed. Redecke et al. (p. 227 , published online 29 November; see the Perspective by Helliwell ) used this technique to determine the structure of an enzyme from Trypanosoma brucei , the parasite that causes sleeping sickness, from micron-sized crystals grown within insect cells. The structure shows how this enzyme, which is involved in degradation of host proteins, is natively inhibited prior to activation, which could help in the development of parasite-specific inhibitors.
Stroke-Related Early Tracheostomy Versus Prolonged Orotracheal Intubation in Neurocritical Care Trial (SETPOINT)
2012-11-30

Background and Purpose— Optimal timing of tracheostomy in ventilated patients with severe stroke is unclear. We aimed to investigate feasibility, safety, and potential advantages of early tracheostomy in these intensive care unit (ICU) patients. Methods— This prospective, randomized, parallel-group, controlled, open, and outcome-masked pilot trial was conducted in neurological/neurosurgical ICUs of a university hospital. Patients with severe ischemic or hemorrhagic stroke and an estimated need for at least 2 weeks of ventilation were randomized to either early tracheostomy (within day 1–3 from intubation; early) or to standard tracheostomy (between day 7–14 from intubation if extubation could not be achieved or was not feasible; standard). The primary outcome was length of stay in the ICU; secondary outcomes were diverse aspects of the ICU course. Results— Sixty patients were randomized and analyzed. No differences were observed with regard to the primary outcome length of stay in the ICU (median 18 [interquartile range 16–28] versus 17 [interquartile range 13–22] days, median difference: 1 [−2 to 6]; P =0.38) or to most secondary outcomes, including adverse effects. Instead, use of sedatives (62% versus 42% of ICU stay, median difference 17.5 [3.3–29.2]; P =0.02), ICU mortality (ICU deaths 3 [10%] versus 14 [47%]; P &lt;0.01) and 6-month mortality (deaths 8 [27%] versus 18 [60%]; P =0.02) were lower in the early group than in the standard group, respectively. Conclusions— Early tracheostomy in ventilated intensive care stroke patients is feasible, and safe, and presumably reduces sedation need. Whether the suggested benefits in mortality and outcome truly exist has to be determined by a larger multicenter trial. Clinical Trial Registration— http://www.clinicaltrials.gov . Unique identifier: NCT01261091.