991 research outputs found

    The correspondence between augmentations and rulings for Legendrian knots

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    We strengthen the link between holomorphic and generating-function invariants of Legendrian knots by establishing a formula relating the number of augmentations of a knot's contact homology to the complete ruling invariant of Chekanov and Pushkar.Comment: v2: 10 pages, 3 figures; minor revisions, to appear in Pacific J. Mat

    Invariants of Legendrian Knots and Coherent Orientations

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    We provide a translation between Chekanov's combinatorial theory for invariants of Legendrian knots in the standard contact R^3 and a relative version of Eliashberg and Hofer's Contact Homology. We use this translation to transport the idea of ``coherent orientations'' from the Contact Homology world to Chekanov's combinatorial setting. As a result, we obtain a lifting of Chekanov's differential graded algebra invariant to an algebra over Z[t,t^{-1}] with a full Z grading.Comment: 32 pages, 17 figures; small technical corrections to proof of Thm 3.7 and example 4.

    Pharmacy Curriculum Outcomes Assessment (PCOA) as Predictor of Performance on NAPLEX

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    Objectives: The purpose of the study was to respond to studentsā€™ inquiry regarding the relationship between student performance on the PCOA administered in early spring of the P3 year and performance on the NAPLEX administered post-graduation. Method: PCOA scores for two of the four content areas, Pharmaceutical Sciences and Clinical Sciences, resulting from administration of the assessment for P3 students in 2012 and 2013 were compared to the same student scores for the 2013 and 2014 NAPLEX taken post-graduation. A Pearson product-moment correlation coefficient was calculated to measure the linear correlation between the two sets of exam scores. Additionally, a linear regression was used to explain the predictor, PCOA, variability on the NAPLEX Score. Results: The Pearson product-moment correlation coefficient for the combined PCOA content areas, Pharmaceutical Science and Clinical Science scores, was r=.572. A linear regression established that PCOA Pharmaceutical Science and Clinical Science scores could statistically significantly predict NAPLEX scores, p Implications: Students taking the PCOA exam in the P3 year of their PharmD program may find value in using their performance on the assessment in the areas of Pharmaceutical Science and Clinical Science to predict their performance on the NAPLEX which is blueprinted to these areas of study

    Naturally Occurring Isoleucyl-tRNA Synthetase without tRNA-dependent Pre-transfer Editing

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    Isoleucyl-tRNA synthetase (IleRS) is unusual among aminoacyl-tRNA synthetases in having a tRNA-dependent pre-transfer editing activity. Alongside the typical bacterial IleRS (such as Escherichia coli IleRS), some bacteria also have the enzymes (eukaryote-like) that cluster with eukaryotic IleRSs and exhibit low sensitivity to the antibiotic mupirocin. Our phylogenetic analysis suggests that the ileS1 and ileS2 genes of contemporary bacteria are the descendants of genes that might have arisen by an ancient duplication event before the separation of bacteria and archaea. We present the analysis of evolutionary constraints of the synthetic and editing reactions in eukaryotic/eukaryote-like IleRSs, which share a common origin but diverged through adaptation to different cell environments. The enzyme from the yeast cytosol exhibits tRNA-dependent pre-transfer editing analogous to E. coli IleRS. This argues for the presence of this proofreading in the common ancestor of both IleRS types and an ancient origin of the synthetic site-based quality control step. Yet surprisingly, the eukaryote-like enzyme from Streptomyces griseus IleRS lacks this capacity; at the same time, its synthetic site displays the 10(3)-fold drop in sensitivity to antibiotic mupirocin relative to the yeast enzyme. The discovery that pre-transfer editing is optional in IleRSs lends support to the notion that the conserved post-transfer editing domain is the main checkpoint in these enzymes. We substantiated this by showing that under error-prone conditions S. griseus IleRS is able to rescue the growth of an E. coli lacking functional IleRS, providing the first evidence that tRNA-dependent pre-transfer editing in IleRS is not essential for cell viability

    Quantum correlations between single telecom photons and a multimode on-demand solid-state quantum memory

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    Quantum correlations between long-lived quantum memories and telecom photons that can propagate with low loss in optical fibers are an essential resource for the realization of large-scale quantum information networks. Significant progress has been realized in this direction with atomic and solid-state systems. Here, we demonstrate quantum correlations between a telecom photon and a multimode ondemand solid state quantum memory. This is achieved by mapping a correlated single photon onto a spin collective excitation in a Pr 3+ :Y 2 SiO 5 crystal for a controllable time. The stored single photons are generated by cavity-enhanced spontaneous parametric down-conversion and heralded by their partner photons at telecom wavelength. These results represent the first demonstration of a multimode on-demand solid state quantum memory for external quantum states of light. They provide an important resource for quantum repeaters and pave the way for the implementation of quantum information networks with distant solid state quantum nodes.We acknowledge financial support by the ERC Starting Grant QuLIMA, by the Spanish Ministry of Economy and Competitiveness (MINECO) and Fondo Europeo de Desarrollo Regional (FEDER) (FIS2015-69535-R), by MINECO Severo Ochoa through Grant No. SEV-2015-0522 and through the Ph.D. Fellowship Program (for A.ā€‰S.), by AGAUR via 2014 SGR 1554, by FundaciĆ³ Cellex, and by CERCA Programme/Generalitat de Catalunya

    Off-label use in germany - a current appraisal of gynaecologic university departments

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    <p>Abstract</p> <p>Objective</p> <p>The off-label use, referring to the applicability of pharmaceutical drugs beyond the submitted and from the Federal Institute for Drugs and Medical Devices (BfArM, Bundesamt fĆ¼r Arzneimittel und Medizinprodukte) certified and approved administration, is the subject of controversial discussions. the application can be considered in case of severe illness - if no therapeutic alternatives are available - or it exists as a founded perspective for achieving therapeutic success.</p> <p>Methods</p> <p>A latitudinal study for evaluating the application of off-label use supplements was performed at 43 German university and academic teaching hospitals. Five doctors at each hospital applied off-label pharmaceutical drugs and were called upon to share their personal experience to the application of those medications.</p> <p>Results</p> <p>75 (35%) questionnaires were returned out of 22 (51%) medical centres with 215 contacted physicians. Off-label use was common for 65 (91%) of the physicians. Only 9% of them obviate the application of off-label drugs. About a half of the medication is related to application in obstetrics (54%) and in most cases on an every day basis. Uterotonics were the most commonly used off-label medications (34%). The main part of information about off-label use is obtained from personal information of colleagues (66%) and personal experience (58%). 34% of physicians think that off label use is risky. Interestingly, the view about off label use of medication varies considerably among physicians from various hospitals.</p> <p>Conclusions</p> <p>The application of off-label pharmaceutical drugs in Germany seems to be a well established practice. More than 90% of participators of our trial use at least one medication outside the administration. This includes particularly prostaglandins, anti-hyper-tonic therapeutics and chemotherapeutics.</p

    Spatial enhancer clustering and regulation of enhancer-proximal genes by cohesin

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    In addition to mediating sister chromatid cohesion during the cell cycle, the cohesin complex associates with CTCF and with active gene regulatory elements to form long-range interactions between its binding sites. Genome-wide chromosome conformation capture had shown that cohesin's main role in interphase genome organization is in mediating interactions within architectural chromosome compartments, rather than specifying compartments per se. However, it remains unclear how cohesin-mediated interactions contribute to the regulation of gene expression. We have found that the binding of CTCF and cohesin is highly enriched at enhancers and in particular at enhancer arrays or ā€œsuper-enhancersā€ in mouse thymocytes. Using local and global chromosome conformation capture, we demonstrate that enhancer elements associate not just in linear sequence, but also in 3D, and that spatial enhancer clustering is facilitated by cohesin. The conditional deletion of cohesin from noncycling thymocytes preserved enhancer position, H3K27ac, H4K4me1, and enhancer transcription, but weakened interactions between enhancers. Interestingly, āˆ¼50% of deregulated genes reside in the vicinity of enhancer elements, suggesting that cohesin regulates gene expression through spatial clustering of enhancer elements. We propose a model for cohesin-dependent gene regulation in which spatial clustering of enhancer elements acts as a unified mechanism for both enhancer-promoter ā€œconnectionsā€ and ā€œinsulation.

    Thioredoxin-mimetic peptide CB3 lowers MAPKinase activity in the Zucker rat brain

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    AbstractDiabetes is a high risk factor for dementia. High glucose may be a risk factor for dementia even among persons without diabetes, and in transgenic animals it has been shown to cause a potentiation of indices that are pre-symptomatic of Alzheimerā€²s disease. To further elucidate the underlying mechanisms linking inflammatory events elicited in the brain during oxidative stress and diabetes, we monitored the activation of mitogen-activated kinsase (MAPKs), c-jun NH2-terminal kinase (JNK), p38 MAP kinases (p38MAPK), and extracellular activating kinsae1/2 (ERK1/2) and the anti-inflammatory effects of the thioredoxin mimetic (TxM) peptides, Ac-Cys-Pro-Cys-amide (CB3) and Ac-Cys-Gly-Pro-Cys-amide (CB4) in the brain of male leptin-receptor-deficient Zucker diabetic fatty (ZDF) rats and human neuroblastoma SH-SY5Y cells. Daily i.p. injection of CB3 to ZDF rats inhibited the phosphorylation of JNK and p38MAPK, and prevented the expression of thioredoxin-interacting-protein (TXNIP/TBP-2) in ZDF rat brain. Although plasma glucose/insulin remained high, CB3 also increased the phosphorylation of AMP-ribose activating kinase (AMPK) and inhibited p70S6K kinase in the brain. Both CB3 and CB4 reversed apoptosis induced by inhibiting thioredoxin reductase as monitored by decreasing caspase 3 cleavage and PARP dissociation in SH-SY5Y cells. The decrease in JNK and p38MAPK activity in the absence of a change in plasma glucose implies a decrease in oxidative or neuroinflammatory stress in the ZDF rat brain. CB3 not only attenuated MAPK phosphorylation and activated AMPK in the brain, but it also diminished apoptotic markers, most likely acting via the MAPKā€“AMPKā€“mTOR pathway. These results were correlated with CB3 and CB4 inhibiting inflammation progression and protection from oxidative stress induced apoptosis in human neuronal cells. We suggest that by attenuating neuro-inflammatory processes in the brain Trx1 mimetic peptides could become beneficial for preventing neurological disorders associated with diabetes

    Target specificity among canonical nuclear poly(A) polymerases in plants modulates organ growth and pathogen response

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    Polyadenylation of pre-mRNAs is critical for efficient nuclear export, stability, and translation of the mature mRNAs, and thus for gene expression. The bulk of pre-mRNAs are processed by canonical nuclear poly(A) polymerase (PAPS). Both vertebrate and higher-plant genomes encode more than one isoform of this enzyme, and these are coexpressed in different tissues. However, in neither case is it known whether the isoforms fulfill different functions or polyadenylate distinct subsets of pre-mRNAs. Here we show that the three canonical nuclear PAPS isoforms in Arabidopsis are functionally specialized owing to their evolutionarily divergent C-terminal domains. A strong loss-of-function mutation in PAPS1 causes a male gametophytic defect, whereas a weak allele leads to reduced leaf growth that results in part from a constitutive pathogen response. By contrast, plants lacking both PAPS2 and PAPS4 function are viable with wild-type leaf growth. Polyadenylation of SMALL AUXIN UP RNA (SAUR) mRNAs depends specifically on PAPS1 function. The resulting reduction in SAUR activity in paps1 mutants contributes to their reduced leaf growth, providing a causal link between polyadenylation of specific pre-mRNAs by a particular PAPS isoform and plant growth. This suggests the existence of an additional layer of regulation in plant and possibly vertebrate gene expression, whereby the relative activities of canonical nuclear PAPS isoforms control de novo synthesized poly(A) tail length and hence expression of specific subsets of mRNAs

    Cardioprotection by systemic dosing of thymosin beta four following ischemic myocardial injury

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    Thymosin beta 4 (TĪ²4) was previously shown to reduce infarct size and improve contractile performance in chronic myocardial ischemic injury via two phases of action: an acute phase, just after injury, when TĪ²4 preserves ischemic myocardium via antiapoptotic or anti-inflammatory mechanisms; and a chronic phase, when TĪ²4 activates the growth of vascular or cardiac progenitor cells. In order to differentiate between the effects of TĪ²4 during the acute and during the chronic phases, and also in order to obtain detailed hemodynamic and biomarker data on the effects of TĪ²4 treatment suitable for use in clinical studies, we tested TĪ²4 in a rat model of chronic myocardial ischemia using two dosing regimens: short term dosing (TĪ²4 administered only during the first 3 days following injury), and long term dosing (TĪ²4 administered during the first 3 days following injury and also every third day until the end of the study). TĪ²4 administered throughout the study reduced infarct size and resulted in significant improvements in hemodynamic performance; however, chamber volumes and ejection fractions were not significantly improved. TĪ²4 administered only during the first 3 days following injury tended to reduce infarct size, chamber volumes and improve hemodynamic performance. Plasma biomarkers of myocyte injury were significantly reduced by TĪ²4 treatment during the acute injury period, and plasma ANP levels were significantly reduced in both dosing groups. Surprisingly, neither acute nor chronic TĪ²4 treatment significantly increased blood vessel density in peri-infarct regions. These results suggest the following: repeated dosing may be required to achieve clinically measureable improvements in cardiac function post-myocardial infarction (MI); improvement in cardiac function may be observed in the absence of a high degree of angiogenesis; and that plasma biomarkers of cardiac function and myocardial injury are sensitive pharmacodynamic biomarkers of the effects of TĪ²4
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