julilili42/papers huggingface dataset:
Regulation and Physiological Roles of Serum- and Glucocorticoid-Induced Protein Kinase Isoforms
2001-11-13

Serum- and glucocorticoid-induced protein kinase 1 ( SGK1 ) was identified in 1993 as an immediate early gene whose mRNA levels increase dramatically within 30 minutes when cells are exposed to serum or glucocorticoids, or both. Subsequently, many other agonists, acting through a variety of signal transduction pathways, have been shown to induce SGK1 gene transcription in cells and tissues. SGK1 is a member of the "AGC" subfamily, which includes protein kinases A, G, and C, and its catalytic domain is most similar to protein kinase B (PKB). Like PKB, SGK1 is activated by phosphorylation in response to signals that stimulate phosphatidylinositol 3-kinase, and this is mediated by 3-phosphoinositide-dependent protein kinase 1 (PDK1) and another protein kinase that has yet to be identified. Thus, SGK1 is remarkable in being activated at both the transcriptional and posttranslational levels by a huge number of extracellular signals. In contrast, little is known about the transcriptional regulation of the two closely related isoforms SGK2 and SGK3, although they can be activated by phosphorylation. The substrate specificity of SGK isoforms superficially resembles that of PKB in that serine and threonine residues lying in Arg-Xaa-Arg-Xaa-Xaa-Ser/Thr sequences (where Xaa is a variable amino acid) are phosphorylated. However, although they may have some substrates in common, evidence is emerging that SGK1 and PKB phosphorylate distinct proteins and have different functions in vivo. In particular, SGK1 plays an important role in activating certain potassium, sodium, and chloride channels, suggesting an involvement in the regulation of processes such as cell survival, neuronal excitability, and renal sodium excretion. Moreover, sustained high levels of SGK1 protein and activity may contribute to conditions such as hypertension and diabetic nephropathy. This raises the possibility that specific inhibitors of SGK1 may have therapeutic potential for the treatment of several diseases.
Regulation and Physiological Roles of Serum- and Glucocorticoid-Induced Protein Kinase Isoforms
2001-11-13

Serum- and glucocorticoid-induced protein kinase 1 (SGK1) was identified in 1993 as an immediate early gene whose mRNA levels increase dramatically within 30 minutes when cells are exposed to serum or glucocorticoids, or both. Subsequently, many other agonists, acting through a variety of signal transduction pathways, have been shown to induce SGK1 gene transcription in cells and tissues. SGK1 is a member of the "AGC" subfamily, which includes protein kinases A, G, and C, and its catalytic domain is most similar to protein kinase B (PKB). Like PKB, SGK1 is activated by phosphorylation in response to signals that stimulate phosphatidylinositol 3-kinase, and this is mediated by 3-phosphoinositide-dependent protein kinase 1 (PDK1) and another protein kinase that has yet to be identified. Thus, SGK1 is remarkable in being activated at both the transcriptional and posttranslational levels by a huge number of extracellular signals. In contrast, little is known about the transcriptional regulation of the two closely related isoforms SGK2 and SGK3, although they can be activated by phosphorylation. The substrate specificity of SGK isoforms superficially resembles that of PKB in that serine and threonine residues lying in Arg-Xaa-Arg-Xaa-Xaa-Ser/Thr sequences (where Xaa is a variable amino acid) are phosphorylated. However, although they may have some substrates in common, evidence is emerging that SGK1 and PKB phosphorylate distinct proteins and have different functions in vivo. In particular, SGK1 plays an important role in activating certain potassium, sodium, and chloride channels, suggesting an involvement in the regulation of processes such as cell survival, neuronal excitability, and renal sodium excretion. Moreover, sustained high levels of SGK1 protein and activity may contribute to conditions such as hypertension and diabetic nephropathy. This raises the possibility that specific inhibitors of SGK1 may have therapeutic potential for the treatment of several diseases.
Multiplicative renormalizability of gluon and ghost propagators in QCD
2001-11-13

We reformulate the coupled set of continuum equations for the renormalized\\ngluon and ghost propagators in QCD, such that the multiplicative\\nrenormalizability of the solutions is manifest, independently of the specific\\nform of full vertices and renormalization constants. In the Landau gauge, the\\nequations are free of renormalization constants, and the renormalization point\\ndependence enters only through the renormalized coupling and the renormalized\\npropagator functions. The structure of the equations enables us to devise novel\\ntruncations with solutions that are multiplicatively renormalizable and agree\\nwith the leading order perturbative results. We show that, for infrared power\\nlaw behaved propagators, the leading infrared behavior of the gluon equation is\\nnot solely determined by the ghost loop, as concluded in previous studies, but\\nthat the gluon loop, the three-gluon loop, the four-gluon loop, and even\\nmassless quarks also contribute to the infrared analysis. In our new Landau\\ngauge truncation, the combination of gluon and ghost loop contributions seems\\nto reject infrared power law solutions, but massless quark loops illustrate how\\nadditional contributions to the gluon vacuum polarization could reinstate these\\nsolutions. Moreover, a schematic study of the three-gluon and four-gluon loops\\nshows that they too need to be considered in more detail before a definite\\nconclusion about the existence of infrared power behaved gluon and ghost\\npropagators can be reached.\\n
Syncope and Supraventricular Tachycardia
2001-11-13

A 41-year-old man was referred for electrophysiological evaluation after recurrent syncope that occurred frequently during vigorous exercise.The patient had a complete, normal cardiological work up, including a resting ECG, an exercise stress test, and an echocardiogram.He reported that just before loss of consciousness, his heart was beating very fast.An electrophysiological study was performed (Figure), and typical atrioventricular nodal reentrant tachycardia was inducible, with a single atrial premature extrastimulus, after the infusion of 1 mg/h orciprenaline.With the induction of the tachycardia, heart rate increased from 91 beats/min (R-R interval, 660 ms) during sinus rhythm to 175 beats/min (R-R interval, 335 ms), blood pressure dropped from 120/80 mm Hg to 50/40 mm Hg, and mean right atrial pressure increased from 1 mm Hg to 18 mm Hg.Although the patient was in the supine position, he lost consciousness when tachycardia was induced.Successful catheter modification was performed, and the patient remained free of symptoms during a follow-up of 37 months.Displayed are surface leads I, II, III, V 1 , and V 6 .In addition, the recordings from the high right atrium (HRA), the His bundle (HBE), and the right ventricular apex (RVA) are shown.Invasive recordings of blood pressure in the right femoral artery and the right atrium were obtained.A single paced premature atrial contraction (ES) induced a typical slow/fast atrioventricular nodal reentrant tachycardia.Almost instantaneously, arterial blood pressure dropped.
Optimization of intensity modulated radiotherapy under constraints for static and dynamic MLC delivery
2001-11-14

Multi-leaf collimators (MLCs) are emerging as the prevalent modality to apply intensity modulated radiotherapy (IMRT). Both the principle and the particular design of MLCs stipulate complex constraints on the practically applicable intensity modulated radiation fields. Most consequentially, the distribution of exposure times across the maximum field outline is either a piecewise constant function in the static mode or a piecewise linear function in the dynamic mode of driving an MLC. In view of clinical utility, the total leaf movement should be minimized, which requires that MLC-related constraints be considered in the dose optimization process. A method is proposed to achieve this for both static MLC fields and dynamic leaf close-in application. The method is an amendment to a generic gradient-based IMRT dose optimization algorithm and solves numerical problems related to the non-convexity of the MLC constraints, which can cause erratic behaviour of a gradient-based algorithm. It employs bistable penalty functions to select preferrable leaf configurations from the configuration space of the MLC, which is limited by specific design features. Together with an 'annealing' escape mechanism from local minima, the algorithm is capable of finding the optimum of an IMRT problem as leaf sequences with minimized leaf travel. In particular, the efficiency of static IMRT can be raised to the levels of unmodulated fields with very few field segments, thereby increasing the utility of IMRT in clinical practice.
Broadband Detection Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Reveal Enzymatically and Chemically Induced Deamidation Reactions within Peptides
2001-11-14

Among the numerous forms of chemical degradation of peptides or proteins, deamidation is one of the alterations observed most frequently. In this irreversible reaction, a glutamine or an asparagine side chain is hydrolyzed to glutamic acid or aspartic acid, respectively (conversion of NH2 to OH). Besides its influence in the deterioration of biotechnological and food products, deamidation represents a defined posttranslational modification reaction with respect to proteomics. Here mass spectrometric techniques play a leading role in determining posttranslational modifications. However, not all mass spectrometers are able to resolve signal differences of 0.0193 Da (mass difference of 12CO vs 13CNH) for singly charged molecules, the mass difference between the first isotopic signal of an asparagine/glutamine-containing peptide and the monoisotopic signal of the corresponding partially deamidated aspartate/glutamate derivative. To detect partial deamidation within peptides, advantage has been taken of the ability of Fourier transform ion cyclotron resonance mass spectrometry to perform very high mass resolution. In this work, we investigated up to triply charged ions produced by electrospray ionization using direct infusion. Although the special heterodyne detection mode enables higher mass resolution than the routinely used broadband detection, often only a small mass window can be investigated. Using broadband detection, we were able to resolve ions with a difference of m/z 0.0064 to detect partially deamidated peptides formed either enzymatically or under acidic and basic conditions.
The acoustic advantage of hunting at low heights above water: behavioural experiments on the European ‘trawling’ bats Myotis capaccinii, M. dasycneme and M. daubentonii
2001-11-15

SUMMARY We have demonstrated in behavioural experiments that success in capturing prey from surfaces in ‘trawling Myotis’ (Leuconoë-type) depends on the acoustic properties of the surface on which the prey is presented. Two types of surface structure were ensonified with artificial bat signals to probe their acoustic characteristics. We have shown that perception of prey by echolocation is easier if the prey is presented on a smooth surface (such as calm water) than if it is presented on a structured surface (such as vegetation or the ground). This is because the smooth surface reflects a much lower level of clutter echoes than the structured one if ensonified at an angle typical for bats foraging low over water. The ensonification experiments revealed that the sound pressure level of the echo was even higher for mealworms on a smooth surface than for mealworms suspended in air. This might be because waves travelling via the surface also contribute to the echo (e.g. reflection from the surface to the mealworm, back to the surface and then to the receiver). From the behavioural experiments, we conclude that ‘trawling Myotis’ take isolated objects on smooth (water) surfaces for prey. Those objects reflect isolated, stationary acoustic glints back to the echolocating bats. Conversely, ‘trawling Myotis’ will not recognise prey if prey echoes are embedded in numerous clutter echoes. We have demonstrated marked similarities between the three European ‘trawling Myotis’ species M. dasycneme, M. daubentonii and M. capaccinii in echolocation behaviour, search image, foraging strategy and prey perception. We propose that a combination of prey abundance and acoustic advantages could have led to repeated and convergent evolution of ‘trawling’ bats in different parts of the world.
Artesunate and Praziquantel for the Treatment ofSchistosoma haematobiumInfections: A Double‐Blind, Randomized, Placebo‐Controlled Study
2001-11-15

Recently, artemisinin derivatives have been shown to be efficacious in chemoprophylaxis of and chemotherapy for Schistosoma japonicum and S. mansoni infections. Therefore, a double-blind, randomized, placebo-controlled study was carried out to investigate the efficacy and tolerability of artesunate plus placebo and the combination of artesunate and praziquantel in the treatment of S. haematobium infections in Gabon. The 300 infected schoolchildren included in the study were randomized to receive artesunate plus placebo (n=90), praziquantel plus placebo (n=90), artesunate and praziquantel (n=90), or only placebo (n=30). End points were efficacy, assessed as cure on day 56, and tolerability. All treatment regimens were well tolerated. The praziquantel plus placebo-treated group attained a cure rate of 73%, artesunate plus placebo a rate of 27%, the combination of artesunate and praziquantel a rate of 81%, and placebo alone a rate of 20%. In summary, earlier findings of efficacy of artemisinin derivitives against S. mansoni and S. japonicum could not be confirmed in S. haematobium infections.
Exploring the past
2001-11-15

In this paper, we present a set of tools and techniques for visualization of and interaction with historical data. First, we briefly describe the data acquisition and preparation. Afterwards, we discuss in detail the interaction approaches for exploration of historical data, containing a time dimension. In particular, we propose (1) a continuous time increment approach for visualizing 3D slices continuously moving in the 4D space; (2) a fly-with mode for viewing the scene from the perspective of the participants in the migration, we are visualizing; (3) a time lens, as an extension of the traditional magic lens for viewing arbitrary event times; (4) a time-space exploration tool for simultaneous viewing more than one event time and location of interest; (5) a guided exploration tool, which allows for viewing events on an interactively defined or pre-defined path in space. Finally, we conclude the paper with a discussion and comparison of the proposed tools.
Pathophysiology of clinical cerebellar signs
2001-11-15

Disorders of the cerebellum may have a large number of etiologies and, therefore, may be associated with a multitude of clinical signs. However, only a small number of clinical signs may be viewed as being specific for cerebellar dysfunction. These clinical hallmarks of cerebellar dysfunction include inaccurate, dysmetric limb movements, disordered gait, dysarthric speech, nystagmus, abnormal oculomotor control, as well as involuntary movements such as terminal and postural tremors. During recent years, a large number of studies have helped to clarify to a considerable extent both the role of the cerebellum in normal movement and the pathophysiological consequences of cerebellar dysfunction. This chapter reviews the major clinical signs of cerebellar disorders and attempts to interpret these signs in the framework of current concepts of normal and pathologic cerebellar motor physiology.
Models of cerebellar function
2001-11-15

Especially because the circuitry of the cerebellum is strikingly uniform and has been relatively well characterized anatomically and physiologically, many investigators have been prompted to devise theories to explain its function. Over the centuries, many conceptions of cerebellar function have been put forward, and it still cannot be said that a consensus view has been achieved. However, despite their seeming diversity, theories of cerebellar function have converged significantly. Useful summaries and reviews of the more historical ideas can be found in several places (Llinas, 1981; Pellionisz, 1985; Thach et al., 1992). In order to afford better quantitative analysis and to take advantage of our growing computer simulation capabilities, models of cerebellar function have been formulated increasingly in mathematical terms. This chapter focuses on these models and attempts to introduce them from a qualitative engineering perspective, with a bare mimimum of mathematical detail. Specifically, it reviews the basic character of cerebellar function, describing it as an adaptive modulator or ‘controller’ of movement, rather than as a principal driver of movement. It then describes the types of signal processing that are thought to occur in the cerebellum and the essential features of the neuronal architecture that would implement these proposed types of computation. The central theoretical principles of controller design that are used to understand and evaluate cerebellar models are then outlined. Specifically, feedforward, feedback, internal model-based, and discontinuous control strategies are discussed. Finally, several specific mathematical models have been selected to highlight important concepts in the evolution of the quantitative thinking about the cerebellum.
Electromagnetic structure of the nucleon in the perturbative chiral quark model
2001-11-19

We apply the perturbative chiral quark model (PCQM) at one loop to analyse\\nthe electromagnetic structure of nucleons. This model is based on an effective\\nLagrangian, where baryons are described by relativistic valence quarks and a\\nperturbative cloud of Goldstone bosons. Including the electromagnetic\\ninteraction we first develop the formalism up to one-loop in the Goldstone\\nboson fluctuation relying on renormalization by use of counterterms. Local\\ngauge invariance is satisfied both on the Lagrangian level and also for the\\nrelevant baryon matrix elements in the Breit frame. We apply the formalism to\\nobtain analytical expressions for the nucleon charge and magnetic form factors,\\nwhich are expressed in terms of fundamental parameters of low-energy\\npion-nucleon physics (weak pion decay constant, axial nucleon coupling, strong\\npion-nucleon form factor) and of only one model parameter (radius of the\\nnucleonic three-quark core). A detailed numerical analysis for the nucleon\\nmagnetic moments, charge and magnetic radii and also for the momentum\\ndependence of form factors is presented.\\n
Stability of the Cyclotron Resonance Scattering Feature in Hercules X‐1 withRXTE
2001-11-20

Five observations of the hard X-ray spectrum of Her X-1 from \\xte show that the keV energy of the cyclotron scattering line is constant within statistics of a few percent per observtion. Comparison with other observations over many years indicates strongly that the centroid energy of this absorption line has increased some time between 1991 and 1993 by 23%, from 34 keV to 41 keV. Moreover, the cutoff energy of the spectral continuum increased at the same time from 16 keV to 20 keV, which is, within the statistical error of 5%, in direct proportion to the centroid. This may be a sign thatboth these characteristics of the spectrum are controlled in the same way by the magnetic field strength in the region of scattering.
New results for 2νββ decay with large particle–particle two-body proton–neutron interaction
2001-11-21

A model many-body Hamiltonian describing an heterogenous system of paired protons and paired neutrons and interacting among themselves through monopole particle-hole and monopole particle-particle interactions is used to study the double beta decay of Fermi type. The states are described by time dependent approaches choosing as trial functions coherent states of the symmetry groups underlying the model Hamiltonian. One formalism, VP1, is fully equivalent with the standard pnQRPA and therefore fails at a critical value of the particle-particle interaction strength while another one, VP2, corresponds to a two step BCS treatment, i.e. the proton quasiparticles are paired with the neutron quasiparticles. In this way a harmonic description for the double beta transition amplitude is provided for any strength of the particle-particle interaction. The approximation quality is judged by comparing the actual results with the exact result as well as with those corresponding to various truncations of the boson expanded Hamiltonian and transition operator. Finally it is shown that the dynamic ground states provided by VP1 and VP2 are reasonable well approximated by solutions of a variational principle. This remark constitutes a step forward finding an approach where the RPA ground state is a solution of a variational principle equation.
UDP‐Glucuronosyltransferases
2001-11-23

UDP-glucuronosyltransferases (UGTs) catalyse a major phase-II reaction of drug metabolism converting lipophilic xenobiotics (bilirubin, steroid hormones, retinoids etc.), drugs and dietary plant constituents into hydrophilic and excretable conjugates. UGTs are bound to the endoplasmic reticulum and nuclear membranes. UGT1 and UGT2 gene families encode 9 and at least 6 human isoforms on chromosomes 2 and 4, respectively. The UGT1 locus represents a novel gene arrangement of exon-1 duplications in which human gene defects are found, such as Crigler-Najjar syndromes leading to severe heritable hyperbilirubinemias and the polymorphic Gilbert syndrome. UGTs are expressed in a tissue specific manner mostly in liver and the gastrointestinal tract, forming a first line defence against dietary toxins, but also in olfactory and steroidogenic tissues and in the brain. For many drugs (morphine, codeine, carboxylic acid-containing NSAIDs, paracetamol, propofol, mycophenolic acid, the irinotecan metabolite SN-38 etc.) glucuronidation represents a major determinant of their pharmacokinetics.
Bicyclic triterpenes as new main products of squalene–hopene cyclase by mutation at conserved tyrosine residues
2001-11-27

The catalytic cavity of the Alicyclobacillus acidocaldarius squalene–hopene cyclase is predominantly lined by aromatic amino acids. In mutant cyclases, the four tyrosine residues in the catalytic cavity were replaced by different amino acids. The mutants showed significant differences in catalytic behavior compared to the wild‐type and to each other. Mutants Y609L, Y609C and Y609S produced the bicyclic main product γ‐polypodatetraene, while Y495L and Y612L showed a wild‐type product pattern and produced hopene as the main product. Altered product patterns were also found with Y420 mutations.
ChemInform Abstract: Anionic Fragments of h‐BN in the Structure La6B4N10.
2001-11-27

Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.