135 research outputs found
Electromagnetic response of a static vortex line in a type-II superconductor : a microscopic study
The electromagnetic response of a pinned Abrikosov fluxoid is examined in the
framework of the Bogoliubov-de Gennes formalism. The matrix elements and the
selection rules for both the single photon (emission - absorption) and two
photon (Raman scattering) processes are obtained. The results reveal striking
asymmetries: light absorption by quasiparticle pair creation or single
quasiparticle scattering can occur only if the handedness of the incident
radiation is opposite to that of the vortex core states. We show how these
effects will lead to nonreciprocal circular birefringence, and also predict
structure in the frequency dependence of conductivity and in the differential
cross section of the Raman scattering.Comment: 14 pages (RevTex
The Nordic Arthroplasty Register Association: A unique collaboration between 3 national hip arthroplasty registries with 280,201 THRs
Background and purpose The possibility of comparing results and of pooling the data has been limited for the Nordic arthroplasty registries, because of different registration systems and questionnaires. We have established a common Nordic database, in order to compare demographics and the results of total hip replacement surgery between countries. In addition, we plan to study results in patient groups in which the numbers are too small to be studied in the individual countries
Long-term symptoms in dizzy patients examined in a university clinic
Background: The long-term course of dizziness was investigated combining medical chart and survey data. The survey was undertaken median (interquartile range (IQR)) 4.6 (4.3) years after the initial medical examination. Methods: Chart data comprised sex, age, diagnosis, symptom duration, postural sway and neck pain. Survey data comprised symptom severity assessed by the Vertigo Symptom Scale – Short Form (VSS-SF), and data regarding current state of dizziness, medication, neck pain and other chronic conditions. Results: The sample consisted of 503 patients, the mean (standard deviation (SD)) age was 50.0 (11.6) years, women being slightly overrepresented (60%). Severe problems with dizziness (VSS-SF mean (SD) 13.9, (10.8)) were indicated in the total group and in 5 of 6 diagnostic sub-groups. Vertigo/balance- and autonomic/anxiety-related symptoms were present in all groups. Current dizziness was confirmed by 73% who had significantly more severe problems than the non-dizzy (VSS-SF mean (SD): 17.2 (10.1) versus 5.0 (7.3)). Symptoms were related to vertigo/balance more than to autonomic/anxiety (test of interaction p < 0.001). Based on simple logistic regression analysis, sex, symptom duration, neck pain, sway and diagnoses predicted dizziness. Symptom duration and neck pain remained predictors in the adjusted analysis. Age, symptom duration, neck pain, sway and diagnoses predicted vertigo/balance-related dizziness in both regression analyses. Sex, neck pain and sway predicted development of autonomic/anxiety-related dizziness according to simple regression analysis, while only neck pain remained a significant predictor in the adjusted analysis. With respect to diagnosis, simple regression analysis showed significant reduced likelihood for development of dizziness in all vestibular sub-groups when compared to the non-otogenic dizziness group. With respect to vertigo/balance- and autonomic/anxiety-related symptoms, the implication of diagnostic belonging varied. No effect of diagnoses was seen in adjusted analyses. Conclusion: The majority of patients had persistent and severe problems with dizziness. The wait-and-see attitude before referral to specialist institutions may be questioned. Early, active movements seem necessary, and attention should be paid to the presence of neck pain. Diagnoses had limited prognostic value. Questionnaire-based evaluations could assist in classification and identification of type of dizziness and thereby provide a better basis for specific rehabilitation
Systematic Analysis of Sequences and Expression Patterns of Drought-Responsive Members of the HD-Zip Gene Family in Maize
Background: Members of the homeodomain-leucine zipper (HD-Zip) gene family encode transcription factors that are unique to plants and have diverse functions in plant growth and development such as various stress responses, organ formation and vascular development. Although systematic characterization of this family has been carried out in Arabidopsis and rice, little is known about HD-Zip genes in maize (Zea mays L.). Methods and Findings: In this study, we described the identification and structural characterization of HD-Zip genes in the maize genome. A complete set of 55 HD-Zip genes (Zmhdz1-55) were identified in the maize genome using Blast search tools and categorized into four classes (HD-Zip I-IV) based on phylogeny. Chromosomal location of these genes revealed that they are distributed unevenly across all 10 chromosomes. Segmental duplication contributed largely to the expansion of the maize HD-ZIP gene family, while tandem duplication was only responsible for the amplification of the HD-Zip II genes. Furthermore, most of the maize HD-Zip I genes were found to contain an overabundance of stress-related ciselements in their promoter sequences. The expression levels of the 17 HD-Zip I genes under drought stress were also investigated by quantitative real-time PCR (qRT-PCR). All of the 17 maize HD-ZIP I genes were found to be regulated by drought stress, and the duplicated genes within a sister pair exhibited the similar expression patterns, suggesting their conserved functions during the process of evolution
Risk of Severe Knee and Hip Osteoarthritis in Relation to Level of Physical Exercise: A Prospective Cohort Study of Long-Distance Skiers in Sweden
Background: To complete long-distance ski races, regular physical exercise is required. This includes not only cross-country skiing but also endurance exercise during the snow-free seasons. The aim of this study was to determine whether the level of physical exercise is associated with future risk of severe osteoarthritis independent of previous diseases and injuries. Methodology/Principal Findings: We used a cohort that consisted of 48 574 men and 5 409 women who participated in the 90 km ski race Vasaloppet at least once between 1989 and 1998. Number of performed races and finishing time were used as estimates of exercise level. By matching to the National Patient Register we identified participants with severe osteoarthritis, defined as arthroplasty of knee or hip due to osteoarthritis. With an average follow-up of 10 years, we identified 528 men and 42 women with incident osteoarthritis. The crude rate was 1.1/1000 person-years for men and 0.8/1000 person-years for women. Compared with racing once, participation in >= 5 races was associated with a 70% higher rate of osteoarthritis (multivariable-adjusted hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.33 to 2.22). The association was dose-dependent with an adjusted HR of 1.09, 95% CI 1.05 to 1.13 for each completed race. A faster finishing time, in comparison with a slow finishing time, was also associated with an increased rate (adjusted HR 1.51, 95% CI 1.14 to 2.01). Contrasting those with 5 or more ski races and a fast finish time to those who only participated once with a slow finish time, the adjusted HR of osteoarthritis was 2.73, 95% CI 1.78 to 4.18. Conclusions/Significance: Participants with multiple and fast races have an increased risk of subsequent arthroplasty of knee and hip due to osteoarthritis, suggesting that intensive exercise may increase the risk
Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape
The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit
Blunted endogenous opioid release following an oral amphetamine challenge in pathological gamblers
Pathological gambling is a psychiatric disorder and the first recognized behavioral addiction, with similarities to substance use disorders but without the confounding effects of drug-related brain changes. Pathophysiology within the opioid receptor system is increasingly recognized in substance dependence, with higher mu-opioid receptor (MOR) availability reported in alcohol, cocaine and opiate addiction. Impulsivity, a risk factor across the addictions, has also been found to be associated with higher MOR availability. The aim of this study was to characterize baseline MOR availability and endogenous opioid release in pathological gamblers (PG) using [(11)C]carfentanil PET with an oral amphetamine challenge. Fourteen PG and 15 healthy volunteers (HV) underwent two [(11)C]carfentanil PET scans, before and after an oral administration of 0.5 mg/kg of d-amphetamine. The change in [(11)C]carfentanil binding between baseline and post-amphetamine scans (ΔBPND) was assessed in 10 regions of interest (ROI). MOR availability did not differ between PG and HV groups. As seen previously, oral amphetamine challenge led to significant reductions in [(11)C]carfentanil BPND in 8/10 ROI in HV. PG demonstrated significant blunting of opioid release compared with HV. PG also showed blunted amphetamine-induced euphoria and alertness compared with HV. Exploratory analysis revealed that impulsivity positively correlated with caudate baseline BPND in PG only. This study provides the first evidence of blunted endogenous opioid release in PG. Our findings are consistent with growing evidence that dysregulation of endogenous opioids may have an important role in the pathophysiology of addictions
Transfer of Neuroplasticity from Nucleus Accumbens Core to Shell Is Required for Cocaine Reward
It is well established that cocaine induces an increase of dendritic spines density in some brain regions. However, few studies have addressed the role of this neuroplastic changes in cocaine rewarding effects and have often led to contradictory results. So, we hypothesized that using a rigorous time- and subject-matched protocol would demonstrate the role of this spine increase in cocaine reward. We designed our experiments such as the same animals (rats) were used for spine analysis and behavioral studies. Cocaine rewarding effects were assessed with the conditioned place preference paradigm. Spines densities were measured in the two subdivisions of the nucleus accumbens (NAcc), core and shell. We showed a correlation between the increase of spine density in NAcc core and shell and cocaine rewarding effects. Interestingly, when cocaine was administered in home cages, spine density was increase in NAcc core only. With anisomycin, a protein synthesis inhibitor, injected in the core we blocked spine increase in core and shell and also cocaine rewarding effects. Strikingly, whereas injection of this inhibitor in the shell immediately after conditioning had no effect on neuroplasticity or behavior, its injection 4 hours after conditioning was able to block neuroplasticity in shell only and cocaine-induced place preference. Thus, it clearly appears that the neuronal plasticity in the NAcc core is essential to induce plasticity in the shell, necessary for cocaine reward. Altogether, our data revealed a new mechanism in the NAcc functioning where a neuroplasticity transfer occurred from core to shell
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