Restricted Basis Research Articles

Do Imaging Findings Predict the Need for Work Restrictions?

Abstract Physicians frequently are asked to assess work ability in individuals with low back pain (LBP) who also require an impairment rating. Physicians may be tempted to base their decisions about the individual's work ability on spinal anatomy/diagnosis as established by imaging, because that may seem objective. However, a review of the current medical literature consistently demonstrates that anatomical abnormalities identified on imaging do not predict functional ability. Rather, recent studies have demonstrated a strong association between the number of symptoms and functional status, on the one hand, and the lack of correlation between findings on imaging and symptoms, on the other hand. For example, a systematic review by Mayo Clinic physicians of 33 published studies in which 3110 asymptomatic adults were imaged using magnetic resonance imaging (MRI) showed that, in middle age when most problematic back pain problems present, roughly half of asymptomatic adults had disc bulges, roughly one-third had disc protrusions, and roughly one-quarter had annular fissures. The authors of the present study also review related studies regarding low back pain and conclude that current scientific knowledge suggests that imaging alone is not useful in predicting function or in assessing future risk. Degenerative changes on imaging are not a sound basis for work restrictions because they do not correlate with risk or capacity.

Dietary phytochemical PEITC restricts tumor development via modulation of epigenetic writers and erasers

Dietary intake of bioactive phytochemicals including the cruciferous vegetable derivative phenethyl isothiocyanate (PEITC) can reduce risk of human cancers, but possible epigenetic mechanisms of these effects are yet unknown. We therefore sought to identify the molecular basis of PEITC-mediated epigenetic tumor restriction. Colon cancer cells treated with low-dose PEITC for >1 month exhibited stable alterations in expression profile of epigenetic writers/erasers and chromatin-binding of histone deacetylases (HDACs) and Polycomb-group (PcG) proteins. Sustained PEITC exposure not only blocked HDAC binding to euchromatin but was also associated with hypomethylation of PcG target genes that are typically hypermethylated in cancer. Furthermore, PEITC treatment induced expression of pro-apoptotic genes in tumor cells, which was partially reversed by overexpression of PcG member BMI-1, suggesting opposing roles for PEITC and PcG proteins in control of tumor progression. These data demonstrate that PEITC regulates chromatin binding of key epigenetic writers/erasers and PcG complexes to restrict tumor development.

Driving After Adolescent Concussion: Advice From Nurse Practitioners in the Absence of Standardized Recommendations

IntroductionNurse practitioners (NPs) are authorized to manage concussion recovery. Common adolescent activities, like driving, are omitted from guidelines. We investigated NP driving guidance and its clinical basis for restriction or limitation following adolescent concussion. MethodNPs completed a web-based questionnaire after viewing a scripted video scenario of an adolescent describing symptoms of concussion occurring 72 hours prior. Driving recommendations were collected using an open-ended query, then coded and categorized by type, characteristic, and basis. Results1,051 (20%) responded to the question of interest. The majority (93.8%) provided driving recommendations: 32.6% based on time, 49.8% based on symptoms, and 28.5% based on health care utilization. 5.3% mentioned fatigue and sleep symptoms. 1% advised use of a standardized assessment tool. DiscussionSymptomatology, examination, and time were key factors in clinical decision-making for post-concussion driving, rather than use of standardized tools. Persistent symptoms that can impact driving, such as sleep and visual disturbances, may warrant consideration.

Classification and dimensional reduction using restricted radial basis function networks

Visualizing high dimensional data by projecting them into two or three dimensional space is one of the most effective ways to intuitively understand the data's underlying characteristics, for example their class neighborhood structure. While data visualization in low dimensional space can be efficient for revealing the data's underlying characteristics, classifying a new sample in the reduced-dimensional space is not always beneficial because of the loss of information in expressing the data. It is possible to classify the data in the high dimensional space, while visualizing them in the low dimensional space, but in this case, the visualization is often meaningless because it fails to illustrate the underlying characteristics that are crucial for the classification process. In this paper, the performance-preserving property of the previously proposed Restricted Radial Basis Function Network in reducing the dimension of labeled data is explained. Here, it is argued through empirical experiments that the internal representation of the Restricted Radial Basis Function Network, which during the supervised learning process organizes a visualizable two dimensional map, does not only preserve the topographical structure of high dimensional data but also captures their class neighborhood structures that are important for classifying them. Hence, unlike many of the existing dimension reduction methods, the Restricted Radial Basis Function Network offers two dimensional visualization that is strongly correlated with the classification process.

Correlated-pair approach to composite-boson scattering lengths

We derive the scattering length of composite bosons (cobosons) within the framework of the composite boson many-body formalism that uses correlated-pair states as a basis, instead of free fermion states. The integral equation constructed from this physically relevant basis makes transparent the role of fermion exchange in the coboson-coboson effective scattering. Three potentials used for Cooper pairs, fermionic-atom dimers, and semiconductor excitons are considered. While the s-wave scattering length for the BCS-like potential is just equal to its Born value, the other two are substantially smaller. For fermionic-atom dimers and semiconductor excitons, our results, calculated within a restricted correlated-pair basis, are in good agreement with those obtained from procedures numerically more demanding. We also propose model coboson-coboson scatterings that are separable and thus easily workable, and that produce scattering lengths which match quantitatively well with the numerically-obtained values for all fermion mass ratios. These separable model scatterings can facilitate future works on many-body effects in coboson gases.

Buchberger–Weispfenning theory for effective associative rings

We present here a new approach for computing Groebner bases for bilateral modules over an effective ring. Our method is based on Weispfenning notion of restricted Groebner bases and related multiplication.

Pentaclorofenol: toxicología y riesgos para el ambiente

El pentaclorofenol (PCP) y su sal sódica, el pentaclorofenato de sodio (NaPCP), son hidrocarburos halogenados de amplio espectro de toxicidad, muy persistentes, usados para la preservación de la madera contra hongos, bacterias e insectos. El PCP y el NaPCP son sustancias de alta toxicidad aguda para humanos que aumenta por la presencia de impurezas como las clorodibenzodioxinas y los clorodibenzofuranos. El PCP tiene graves efectos a largo plazo: es mutágeno, causa alteraciones en los sistemas inmunológico y endocrino, aumenta la susceptibilidad a infecciones y altera las funciones reproductivas. Existen numerosos estudios sobre los efectos adversos de estas sustancias en la salud humana y de los ecosistemas causados por su toxicidad, persistencia, capacidad de bioacumulación y por la toxicidad de sus impurezas. Estos estudios son la base técnica para que el PCP y sus derivados estén severamente restringidos o totalmente prohibidos en numerosos países. En México, el PCP está autorizado para usos forestal, urbano e industrial como preservador de madera; su venta debe estar restringida y su aplicación y manejo deben hacerse bajo la responsabilidad de un técnico autorizado. Existe mucha desinformación entre la población acerca de los riesgos que representa para la salud y el ambiente, el manejo inadecuado de estas sustancias y de sus residuos, por lo que este trabajo pretende difundir la información técnica que existe sobre este tema y recomendar la aplicación de las normas y regulaciones nacionales e internacionales aplicables al manejo de esta sustancia.

What Homophones Say about Words.

The number of potential meanings for a new word is astronomic. To make the word-learning problem tractable, one must restrict the hypothesis space. To do so, current word learning accounts often incorporate constraints about cognition or about the mature lexicon directly in the learning device. We are concerned with the convexity constraint, which holds that concepts (privileged sets of entities that we think of as “coherent”) do not have gaps (if A and B belong to a concept, so does any entity “between” A and B). To leverage from it a linguistic constraint, learning algorithms have percolated this constraint from concepts, to word forms: some algorithms rely on the possibility that word forms are associated with convex sets of objects. Yet this does have to be the case: homophones are word forms associated with two separate words and meanings. Two sets of experiments show that when evidence suggests that a novel label is associated with a disjoint (non-convex) set of objects, either a) because there is a gap in conceptual space between the learning exemplars for a given word or b) because of the intervention of other lexical items in that gap, adults prefer to postulate homophony, where a single word form is associated with two separate words and meanings, rather than inferring that the word could have a disjunctive, discontinuous meaning. These results about homophony must be integrated to current word learning algorithms. We conclude by arguing for a weaker specialization of word learning algorithms, which too often could miss important constraints by focusing on a restricted empirical basis (e.g., non-homophonous content words).

An Intrinsically Disordered Region of the DNA Repair Protein Nbs1 Is a Species-Specific Barrier to Herpes Simplex Virus 1 in Primates.

Humans occasionally transmit herpes simplex virus 1 (HSV-1) to captive primates, who reciprocally harbor alphaherpesviruses poised for zoonotic transmission to humans. To understand the basis for the species-specific restriction of HSV-1 in primates, we simulated what might happen during the cross-species transmission of HSV-1 and found that the DNArepair protein Nbs1 from only some primate species is able to promote HSV-1 infection. The Nbs1 homologs that promote HSV-1 infection also interact with the HSV-1 ICP0 protein. ICP0 interaction mapped to a region of structural disorder in the Nbs1protein. Chimeras reversing patterns of disorder in Nbs1 reversed titers of HSV-1 produced in the cell. By extending this analysis to 1,237 virus-interacting mammalian proteins, we show that proteins that interact with viruses are highly enriched in disorder, suggesting that viruses commonly interact with host proteins through intrinsically disordered domains.

Modal Sense Classification At Large

Modal verbs have different interpretations depending on their context. Their sense categories – epistemic, deontic and dynamic – provide important dimensions of meaning for the interpretation of discourse. Previous work on modal sense classification achieved relatively high performance using shallow lexical and syntactic features drawn from small-size annotated corpora. Due to the restricted empirical basis, it is difficult to assess the particular difficulties of modal sense classification and the generalization capacity of the proposed models. In this work we create large-scale, high-quality annotated corpora for modal sense classification using an automatic paraphrase-driven projection approach. Using the acquired corpora, we investigate the modal sense classification task from different perspectives.

Baculovirus-expressed Plasmodium reichenowi EBA-140 merozoite ligand is host specific

Plasmodium reichenowi, an ape malaria parasite is morphologically identical and genetically similar to Plasmodium falciparum, infects chimpanzees but not humans. Genomic studies revealed that all primate malaria parasites belong to Laverania subgenus. Laverania parasites exhibit strict host specificity, but the molecular mechanisms underlying these host restrictions remain unexplained.Plasmodium merozoites express multiple binding ligands that recognize specific receptors on erythrocytes, including micronemal proteins belonging to P. falciparum EBL family. It was shown that erythrocyte binding antigen-175 (EBA-175), erythrocyte binding ligand-1 (EBL-1), erythrocyte binding antigen-140 (EBA-140) recognize erythrocyte surface sialoglycoproteins - glycophorins A, B, C, respectively. EBA-140 merozoite ligand hijacks glycophorin C (GPC), a minor erythrocyte sialoglycoprotein, to invade the erythrocyte through an alternative invasion pathway.A homolog of P. falciparum EBA-140 protein was identified in P. reichenowi. The amino acid sequences of both EBA-140 ligands are very similar, especially in the conservative erythrocyte binding region (Region II). It has been suggested that evolutionary changes in the sequence of EBL proteins may be associated with Plasmodium host restriction.In this study we obtained, for the first time, the recombinant P. reichenowi EBA-140 ligand Region II using baculovirus expression vector system. We show that the ape EBA-140 Region II is host specific and binds to chimpanzee erythrocytes in the dose and sialic acid dependent manner. Further identification of the erythrocyte receptor for this ape ligand is of great interests, since it may reveal the molecular basis of host restriction of both P. reichenowi and its deadliest human counterpart, P. falciparum.

The crystal structure of the major pneumococcal autolysin LytA in complex with a large peptidoglycan fragment reveals the pivotal role of glycans for lytic activity.

The pneumococcal autolysin LytA is a key virulence factor involved in several important functions including DNA competence, immune evasion and biofilm formation. Here, we present the 1.05 Å crystal structure of the catalytic domain of LytA in complex with a synthetic cell-wall-based peptidoglycan (PG) ligand that occupies the entire Y-shaped substrate-binding crevice. As many as twenty-one amino-acid residues are engaged in ligand interactions with a majority of these interactions directed towards the glycan strand. All saccharides are intimately bound through hydrogen bond, van der Waals and CH-π interactions. Importantly, the structure of LytA is not altered upon ligand binding, whereas the bound ligand assumes a different conformation compared to the unbound NMR-based solution structure of the same PG-fragment. Mutational study reveals that several non-catalytic glycan-interacting residues, structurally conserved in other amidases from Gram-positive Firmicutes, are pivotal for enzymatic activity. The three-dimensional structure of the LytA/PG complex provides a novel structural basis for ligand restriction by the pneumococcal autolysin, revealing for the first time an importance of the multivalent binding to PG saccharides.

Effector-Triggered Immunity Determines Host Genotype-Specific Incompatibility in Legume-Rhizobium Symbiosis.

Symbiosis between legumes and rhizobia leads to the formation of N2-fixing root nodules. In soybean, several host genes, referred to as Rj genes, control nodulation. Soybean cultivars carrying the Rj4 gene restrict nodulation by specific rhizobia such as Bradyrhizobium elkanii We previously reported that the restriction of nodulation was caused by B. elkanii possessing a functional type III secretion system (T3SS), which is known for its delivery of virulence factors by pathogenic bacteria. In the present study, we investigated the molecular basis for the T3SS-dependent nodulation restriction in Rj4 soybean. Inoculation tests revealed that soybean cultivar BARC-2 (Rj4/Rj4) restricted nodulation by B. elkanii USDA61, whereas its nearly isogenic line BARC-3 (rj4/rj4) formed nitrogen-fixing nodules with the same strain. Root-hair curling and infection threads were not observed in the roots of BARC-2 inoculated with USDA61, indicating that Rj4 blocked B. elkanii infection in the early stages. Accumulation of H2O2 and salicylic acid (SA) was observed in the roots of BARC-2 inoculated with USDA61. Transcriptome analyses revealed that inoculation of USDA61, but not its T3SS mutant in BARC-2, induced defense-related genes, including those coding for hypersensitive-induced responsive protein, which act in effector-triggered immunity (ETI) in Arabidopsis. These findings suggest that B. elkanii T3SS triggers the SA-mediated ETI-type response in Rj4 soybean, which consequently blocks symbiotic interactions. This study revealed a common molecular mechanism underlying both plant-pathogen and plant-symbiont interactions, and suggests that establishment of a root nodule symbiosis requires the evasion or suppression of plant immune responses triggered by rhizobial effectors.

4. β-Deliverin: A Small Molecule for Improving Gene Transfer to Hematopoietic Stem Cells and Probing Mechanisms of Lentiviral Vector Restriction

A major obstacle to the success of gene therapy for hematologic disorders is the inefficiency of lentiviral vector (LV) gene transfer to hematopoietic stem cells (HSCs). Achieving clinically relevant gene delivery levels requires prolonged ex vivo culture of HSCs with cytokines and large LV doses. Rapamycin, PGE2, and other small molecules, have been reported to increase LV transduction of HSCs, however the mechanism of action of these drugs and the basis for LV restriction in HSCs are poorly understood.Here, we report a novel small molecule, β-deliverin, which improves LV gene transfer to HSCs up to 3 fold over DMSO control in vitro. This effect is most pronounced in human adult peripheral blood-derived HSCs, but also observed in human cord-derived HSCs, and in non-human primate bone marrow-derived HSCs. Importantly, treatment with β-deliverin does not significantly affect the viability or expansion of HSCs in culture. Furthermore, for cord-derived HSCs, there was no reduction in the number or type of colony-forming cells. In vivo, β-deliverin treated HSCs engraft in the peripheral blood of NSG mice at levels comparable to control at 16 weeks post-engraftment. Despite an only modest increase in transduction efficiency in β-deliverin-treated cord-derived HSCs transduced in vitro (26% versus 20% for control), the marking frequency for control cells dropped to <5% in the peripheral blood of NSG mice 16 weeks post-engraftment, while mice engrafted with β-deliverin treated HSCs retained on average 20% marking. Our data suggest that β-deliverin treatment increases gene marking in long-term repopulating cells without reducing proliferation, differentiation or engraftment potential.Mechanistically, β-deliverin acts at the stage of viral fusion; the rate of fusion is increased more than 2-fold in the presence of β-deliverin. We show, by confocal microscopy, that the proportion and intensity of virus signal localized to EEA1-labelled early endosomes is unchanged by drug treatment, suggesting that viral entry is not affected. In further support of this, LDLR surface expression and receptor density is unchanged following β-deliverin treatment. In β-deliverin treated cells, 2 hours post-transduction, we observed reduced accumulation of virus in late endosomes, a 3-fold reduction in the total number of late endosomes, as measured by LAMP1 puncta, and a nearly 2-fold increase in the proportion of early endosomes when compared to control cells. Together, our data imply that β-deliverin facilitates more efficient exit of virus from the endosome, possibly by inhibiting endosomal maturation. Further mechanistic studies are ongoing. Notably, a monomer of β-deliverin has no effect on HSC transduction, suggesting an important structure-function relationship.β-deliverin is a promising tool not only for the development of novel gene delivery applications, but also to further elucidate LV-HSC interactions. We are investigating whether the mechanisms we observed here hold true for other small molecule transduction enhancers, and using these drugs to probe the biology of LV restriction in HSCs.

Prevalence and Seasonality of the Amphibian Chytrid Fungus Batrachochytrium dendrobatidis Along Widely Separated Longitudes Across the United States.

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has been implicated in amphibian declines on almost all continents. We report on prevalence and intensity of Bd in the United States amphibian populations across three longitudinally separated north-to-south transects conducted at 15 Department of Defense installations during two sampling periods (late-spring/early summer and mid to late summer). Such a standardized approach minimizes the effects of sampling and analytical bias, as well as human disturbance (by sampling restricted military bases), and therefore permits a cleaner interpretation of environmental variables known to affect chytrid dynamics such as season, temperature, rainfall, latitude, and longitude. Our prevalence of positive samples was 20.4% (137/670), and our mean intensity was 3.21 zoospore equivalents (SE=1.03; range 0.001-103.59). Of the 28 amphibian species sampled, 15 tested positive. Three sites had no evidence of Bd infection; across the remaining 12 Bd-positive sites, neither infection prevalence nor intensity varied systematically. We found a more complicated pattern of Bd prevalence than anticipated. Early season samples showed no trend associated with increasing temperature and precipitation and decreasing (more southerly) latitudes; while in late season samples, the proportion of infected individuals decreased with increasing temperature and precipitation and decreasing latitudes. A similar pattern held for the east-west gradient, with the highest prevalence associated with more easterly/recently warmer sites in the early season then shifting to more westerly/recently cooler sites in the later season. Bd intensity across bases and sampling periods was comparatively low. Some of the trends in our data have been seen in previous studies, and our results offer further continental-level Bd sampling over which more concentrated local sampling efforts can be overlaid.

Evaluation of the kinetic parameters of the hydrogen oxidation reaction on nanostructured iridium electrodes in alkaline solution

The kinetic study of the hydrogen oxidation reaction on a nanostructured iridium electrode was carried out in alkaline solution at different rotation rates. The electrode, prepared by sputtering on a glassy carbon substrate, was characterized by cyclic voltammetry, AFM and XPS techniques. Then, the experimental current density (j) vs. overpotential (η) curves were recorded in the range comprised between −0.015≤η /V≤0.30. The correlation of the resulting curves was carried out considering the Tafel-Heyrovsky-Volmer mechanism, with a Frumkin type isotherm for the adsorption of the reaction intermediate. The kinetic parameters (equilibrium reaction rates of the elementary steps and surface coverage of the adsorbed hydrogen) were evaluated. The results obtained indicate that, in the potential range evaluated, the reaction takes place mainly through the Tafel-Volmer route with a small contribution of the Heyrovsky-Volmer route. Finally, an explanation for the lower electrocatalytic activity observed in alkaline solutions with respect to that in acid solutions was proposed, on the basis of the movement restrictions of the hydroxyl ion inside the superficial water network to make possible the electron transference in the Volmer and Heyrovsky steps.

Implementation of fractional-order transfer functions in the viewpoint of the required fractional-order capacitors

ABSTRACTIn this paper, based on the concept of restricted difference basis (RDB) for a natural number, the general structures of the pseudo state-space realisations of some classes of commensurate fractional-order transfer functions are obtained. It is shown that the number of needed fractional-order capacitors for implementing a transfer function belonging to each of these classes depends on the commensurate order and also the RDB based on which the pseudo state-space realisation of the considered transfer function is obtained. In this regard, three general classes of commensurate fractional-order transfer functions are introduced which all can be implemented by the same number of fractional-order capacitors. Also, four classes of fractional-order transfer functions of commensurate order are introduced which all can be implemented by only one fractional-order capacitor of order . Finally, as a more general case, four classes of fractional-order transfer functions of commensurate order are studied in aspect of the number and the order of the fractional-order capacitors needed for their implementations. It is proved that these classes of commensurate fractional-order transfer functions can be implemented by r − 1 number of fractional-order capacitors of order .

Theoretical and observational constrainhts on the mass-radius relations of neutron stars

We investigate theoretical and observational constraints on the mass-radius relations for neutron stars. For that purpose we consider the model of neutron stars taking into considerations strong, weak, electromagnetic and gravitational interactions in the equation of state and integrate the structure equations within the Hartle-Thorne formalism for rotating configurations. On the basis of the theoretical restrictions imposed by general relativity, mass-shedding and axisymmetric secular instabilities we calculate the upper and lower bounds for the parameters of neutron stars. Our theoretical calculations have been compared and contrasted with the observational constraints and as a result we show that the observational constraints favor stiff equations of state.

Rj4, a Gene Controlling Nodulation Specificity in Soybeans, Encodes a Thaumatin-Like Protein But Not the One Previously Reported.

Rj4 is a dominant gene in soybeans (Glycine max) that restricts nodulation by many strains of Bradyrhizobium elkanii. The soybean-B. elkanii symbiosis has a low nitrogen-fixation efficiency, but B. elkanii strains are highly competitive for nodulation; thus, cultivars harboring an Rj4 allele are considered favorable. Cloning the Rj4 gene is the first step in understanding the molecular basis of Rj4-mediated nodulation restriction and facilitates the development of molecular tools for genetic improvement of nitrogen fixation in soybeans. We finely mapped the Rj4 locus within a small genomic region on soybean chromosome 1, and validated one of the candidate genes as Rj4 using both complementation tests and CRISPR/Cas9-based gene knockout experiments. We demonstrated that Rj4 encodes a thaumatin-like protein, for which a corresponding allele is not present in the surveyed rj4 genotypes, including the reference genome Williams 82. Our conclusion disagrees with the previous report that Rj4 is the Glyma.01G165800 gene (previously annotated as Glyma01g37060). Instead, we provide convincing evidence that Rj4 is Glyma.01g165800-D, a duplicated and unique version of Glyma.01g165800, that has evolved the ability to control symbiotic specificity.

The low-FODMAP diet for irritable bowel syndrome: Lights and shadows

Irritable bowel syndrome (IBS) affects 10–15% of the western population. Drug therapy for this entity has shown limited efficacy. The low Fermentable Oligo-, Di-, Monosaccharides And Polyols (FODMAP) diet has recently emerged as an effective intervention for reducing gastrointestinal symptoms in IBS. Currently, several mechanistic studies have proven the rational basis of carbohydrate restriction. In addition, high-quality evidence (prospective studies and randomized controlled trials) from a variety of countries supports the high effectiveness of a low-FODMAP diet for IBS symptoms (70%), especially abdominal bloating, pain, and diarrhea. Importantly, this diet seems to be superior to a gluten-free diet for patients with non-celiac gluten sensitivity. The most controversial features of the low FODMAP diet are its short- and long-term limitations (a high level of restriction, the need for monitoring by an expert dietitian, potential nutritional deficiencies, significant gut microbiota reduction, lack of predictors of response), as well as the potential lack of advantage over alternative dietary, pharmacological and psychological interventions for IBS. Although liberalization of carbohydrate intake is recommended in the long-term, the reintroduction process remains to be clarified as, theoretically, global carbohydrate restriction is deemed to be necessary to avoid additive effects.