253 research outputs found

    Stark shift and parity non-conservation for near-degenerate states of xenon

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    We identify a pair of near-degenerate states of opposite parity in atomic Xe, the 5p510s2[3/2]2o5p^5 10s \,\, ^2[3/2]_2^o at E=94759.927\rm{E}=94759.927 cm1^{-1} and 5p56f2[5/2]25p^5 6f \,\, ^2[5/2]_2 at E=94759.935\rm{E}= 94759.935 cm1^{-1}, for which parity- and time-odd effects are expected to be enhanced by the small energy separation. We present theoretical calculations which indicate narrow widths for both states and we report a calculated value for the weak matrix element, arising from configuration mixing, of W=2.1|W|=2.1 Hz for 132^{132}Xe. In addition, we measured the Stark effect of the 5p56f5p^5\,6f 2[5/2]2^2[5/2]_{2} and 5p56f 2[3/2]25p^5 \,6f \ ^2[3/2]_2 (E=94737.121cm1\rm{E} =94737.121\,\rm{cm}^{-1}) states. The Stark-shift of the 6f6f states is observed to be negative, revealing the presence of nearby 6g6g states at higher energies, which have not been observed before. The Stark-shift measurements imply an upper limit on the weak matrix element of W ⁣< ⁣5|W|\!<\!5 Hz for the near-degenerate states (10s2[3/2]2o10s \,\, ^2[3/2]_2^o and 6f2[5/2]26f \,\, ^2[5/2]_2), which is in agreement with the presented calculations.Comment: 11 pages, 6 figure

    Adipose-derived stromal cells protect intervertebral disc cells in compression: implications for stem cell regenerative disc therapy

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    INTRODUCTION: Abnormal biomechanics plays a role in intervertebral disc degeneration. Adipose-derived stromal cells (ADSCs) have been implicated in disc integrity; however, their role in the setting of mechanical stimuli upon the disc's nucleus pulposus (NP) remains unknown. As such, the present study aimed to evaluate the influence of ADSCs upon NP cells in compressive load culture. METHODS: Human NP cells were cultured in compressive load at 3.0MPa for 48 hours with or without ADSCs co-culture (the ratio was 50:50). We used flow cytometry, live/dead staining and scanning electron microscopy (SEM) to evaluate cell death, and determined the expression of specific apoptotic pathways by characterizing the expression of activated caspases-3, -8 and -9. We further used real-time (RT-) PCR and immunostaining to determine the expression of the extracellular matrix (ECM), mediators of matrix degradation (e.g. MMPs, TIMPs and ADAMTSs), pro-inflammatory factors and NP cell phenotype markers. RESULTS: ADSCs inhibited human NP cell apoptosis via suppression of activated caspase-9 and caspase-3. Furthermore, ADSCs protected NP cells from the degradative effects of compressive load by significantly up-regulating the expression of ECM genes (SOX9, COL2A1 and ACAN), tissue inhibitors of metalloproteinases (TIMPs) genes (TIMP-1 and TIMP-2) and cytokeratin 8 (CK8) protein expression. Alternatively, ADSCs showed protective effect by inhibiting compressive load mediated increase of matrix metalloproteinases (MMPs; MMP-3 and MMP-13), disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs; ADAMTS-1 and 5), and pro-inflammatory factors (IL-1beta, IL-6, TGF-beta1 and TNF-alpha). CONCLUSIONS: Our study is the first in vitro study assessing the impact of ADSCs on NP cells in an un-physiological mechanical stimulation culture environment. Our study noted that ADSCs protect compressive load induced NP cell death and degradation by inhibition of activated caspase-9 and -3 activity; regulating ECM and modulator genes, suppressing pro-inflammatory factors and preserving CK8. Consequently, the protective impact of ADSCs found in this study provides an essential understanding and expands our knowledge as to the utility of ADSCs therapy for intervertebral disc regeneration.published_or_final_versio

    Down-regulated CK8 expression in human intervertebral disc degeneration

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    As an intermediate filament protein, cytokeratin 8 (CK8) exerts multiple cellular functions. Moreover, it has been identified as a marker of notochord cells, which play essential roles in human nucleus pulposus (NP). However, the distribution of CK8 positive cells in human NP and their relationship with intervertebral disc degeneration (IDD) have not been clarified until now. Here, we found the percentage of CK8 positive cells in IDD (25.7+/-4.14%) was significantly lower than that in normal and scoliosis NP (51.9+/-9.73% and 47.8+/-5.51%, respectively, p<0.05). Western blotting and qRT-PCR results confirmed the down-regulation of CK8 expression in IDD on both of protein and mRNA levels. Furthermore, approximately 37.4% of cell clusters were CK8 positive in IDD. Taken together, this is the first study to show a down-regulated CK8 expression and the percentage of CK8 positive cell clusters in IDD based upon multiple lines of evidence. Consequently, CK8 positive cells might be considered as a potential option in the development of cellular treatment strategies for NP repair.published_or_final_versio

    Inverted hysteresis and negative remanence in a homogeneous antiferromagnet

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    Magnetic remanence - found in bar magnets or magnetic storage devices - is probably the oldest and most ubiquitous phenomenon underpinning technological applications of magnetism. It is a macroscopic non-equilibrium phenomenon: a remanent magnetisation appears when a magnetic field is applied to an initially unmagnetised ferromagnet, and then taken away. Here, we present an inverted magnetic hysteresis loop in the pyrochlore compound Nd2_2Hf2_2O7_7: the remanent magnetisation points in a direction opposite to the applied field. This phenomenon is exquisitely tunable as a function of the protocol in field and temperature, and it is reproducible as in a quasi-equilibrium setting. We account for this phenomenon in considerable detail in terms of the properties of non-equilibrium population of domain walls which exhibit a magnetic moment between domains of an ordered antiferromagnetic state which itself has zero net magnetisation. Properties and (non-equilibrium) dynamics of topological defects play an important role in modern spintronics, and our study adds an instance where a uniform field couples selectively to domain walls rather than the bulk.Comment: 5 pages, 3 figures in main article and 7 pages, 13 figures in supplementary material

    Fabrication of ZnS-Bi-TiO 2 Composites and Investigation of Their Sunlight Photocatalytic Performance

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    The ZnS-Bi-TiO 2 composites were prepared by the sol-gel method and were characterized by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-visible diffuse reflectance spectroscopy (UV-Vis DRS). It is found that the doped Bi as Bi 4+ /Bi 3+ species existed in composites, and the introducing of ZnS enhanced further the light absorption ability of TiO 2 in visible region and reduced the recombination of photogenerated electrons and holes. As compared to pure TiO 2 , the ZnS-Bi-TiO 2 exhibited enhanced photodegradation efficiency under xenon lamp irradiation, and the kinetic constant of methyl orange removal with ZnS-Bi-Ti-0.005 (0.0141 min −1 ) was 3.9 times greater than that of pure TiO 2 (0.0029 min −1 ), which could be attributed to the existence of Bi 4+ /Bi 3+ species, the ZnS/TiO 2 heterostructure

    A Water Futures approach on water demand forecasting with online ensemble learning

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    This study presents a collaborative framework developed by the Water Futures team of researchers for the “Battle of the Water Demand Forecasting” challenge at the 3rd International WDSA-CCWI Joint Conference. The framework integrates an ensemble of machine learning forecasting models into a deterministic outcome consistent with the competition formulation. The water demand trajectory over a week exhibits complex overlapping patterns and non-linear dependencies to multiple features and time-dependent events that a single model cannot accurately predict. As such, the reconciled forecast from an ensemble of models exceeds the performance of the individual ones and exhibits higher stability across the weeks of the year and district metered areas considered

    Is impaired lung function related to spinal deformities in patients with adolescent idiopathic scoliosis? A systematic review and meta-analysis-SOSORT 2019 award paper

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    Purpose: Some teenagers with adolescent idiopathic scoliosis (AIS) display compromised lung function. However, the evidence regarding the relations between pulmonary impairments and various spinal deformity parameters in these patients remains unclear, which affects clinical management. This systematic review and meta-analysis aimed to summarize the associations between various lung function parameters and radiographic features in teenagers with AIS. Methods: A search of PubMed, Embase, PEDro, SPORTDiscus, CINAHL, Cochrane Library, and PsycINFO (from inception to March 14, 2022) without language restriction. Original studies reporting the associations between lung function and spinal deformity in patients with AIS were selected. Independent reviewers extracted data and evaluated the methodological quality of the included studies according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pearson correlation and 95% confidence intervals were calculated using random-effects meta-analysis. Results: Twenty-seven studies involving 3162 participants were included. Limited-quality evidence supported that several spinal parameters were significantly related to lung function parameters (e.g., absolute value and percent of the predicted forced vital capacity (FVC; %FVC), forced expiratory volume in one second (FEV1; þV1), and total lung capacity (TLC; %TLC)) in AIS patients. Specifically, meta-analyses showed that main thoracic Cobb angles in the coronal plane were significantly and negatively related to FVC (r = − 0.245), %FVC (r = − 0.302), FEV1 (r = − 0.232), þV1 (r = − 0.348), FEV1/FVC ratio (r = − 0.166), TLC (r = − 0.302), %TLC (r = − 0.183), and percent predicted vital capacity (r = − 0.272) (p &lt; 0.001). Similarly, thoracic apical vertebral rotation was negatively associated with %FVC (r = − 0.215) and %TLC (r = − 0.126) (p &lt; 0.05). Conversely, thoracic kyphosis angles were positively related to %FVC (r = 0.180) and þV1 (r = 0.193) (p &lt; 0.05). Conclusion: Larger thoracic Cobb angles, greater apical vertebral rotation angle, or hypokyphosis were significantly associated with greater pulmonary impairments in patients with AIS, although the evidence was limited. From a clinical perspective, the results highlight the importance of minimizing the three-dimensional spinal deformity in preserving lung function in these patients. More research is warranted to confirm these results

    Measurement properties of self-reported outcome measures for older adults with nonspecific low back pain: a systematic review

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    Abstract Objective: To summarise the measurement properties of patient-reported outcome measures (PROMs) for older adults with nonspecific low back pain. Methods: Eight databases were searched from inception to January 2024. Two independent reviewers conducted article screening, data extraction, risk of bias assessments, evaluations of measurement properties of PROMs, syntheses of quality of evidence and forming recommendation levels using relevant checklists and assessment tools. Results: Ten PROMs were identified from 12 included studies. The Functional Rating Index, Oswestry Disability Index, Roland Morris Disability Questionnaire and Quebec Back Pain Disability Scale demonstrated the highest recommendation (category A: PROM most suitable) for evaluating pain-related functional limitation or pain intensity in older adults with acute, subacute or chronic nonspecific low back pain. The Pain Response to Activity and Positioning questionnaire obtained a category A recommendation for making a differential diagnosis of chronic nonspecific low back pain in older adults. The 36-Item World Health Organization Disability Assessment Schedule 2.0 was considered promising (category B: PROM recommended) for assessing physical functioning, while the Back Believe Questionnaire, Catastrophizing Avoidance Scale D-65+, Pain Catastrophizing Scale and Psychological Inflexibility in Pain Scale obtained category B recommendation for evaluating negative thoughts in this population, although further validation is warranted. Conclusions: This systematic review identified suitable PROMs for assessing physical function in older adults with nonspecific low back pain, but more studies are needed to evaluate the measurement properties of questionnaires on other outcome domains in this population.Abstract Objective: To summarise the measurement properties of patient-reported outcome measures (PROMs) for older adults with nonspecific low back pain. Methods: Eight databases were searched from inception to January 2024. Two independent reviewers conducted article screening, data extraction, risk of bias assessments, evaluations of measurement properties of PROMs, syntheses of quality of evidence and forming recommendation levels using relevant checklists and assessment tools. Results: Ten PROMs were identified from 12 included studies. The Functional Rating Index, Oswestry Disability Index, Roland Morris Disability Questionnaire and Quebec Back Pain Disability Scale demonstrated the highest recommendation (category A: PROM most suitable) for evaluating pain-related functional limitation or pain intensity in older adults with acute, subacute or chronic nonspecific low back pain. The Pain Response to Activity and Positioning questionnaire obtained a category A recommendation for making a differential diagnosis of chronic nonspecific low back pain in older adults. The 36-Item World Health Organization Disability Assessment Schedule 2.0 was considered promising (category B: PROM recommended) for assessing physical functioning, while the Back Believe Questionnaire, Catastrophizing Avoidance Scale D-65+, Pain Catastrophizing Scale and Psychological Inflexibility in Pain Scale obtained category B recommendation for evaluating negative thoughts in this population, although further validation is warranted. Conclusions: This systematic review identified suitable PROMs for assessing physical function in older adults with nonspecific low back pain, but more studies are needed to evaluate the measurement properties of questionnaires on other outcome domains in this population

    Development of a standardized histopathology scoring system for human intervertebral disc degeneration: an Orthopaedic Research Society Spine Section Initiative

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    Abstract: Background: Histopathological analysis of intervertebral disc (IVD) tissues is a critical domain of back pain research. Identification, description, and classification of attributes that distinguish abnormal tissues form a basis for probing disease mechanisms and conceiving novel therapies. Unfortunately, lack of standardized methods and nomenclature can limit comparisons of results across studies and prevent organizing information into a clear representation of the hierarchical, spatial, and temporal patterns of IVD degeneration. Thus, the following Orthopaedic Research Society (ORS) Spine Section Initiative aimed to develop a standardized histopathology scoring scheme for human IVD degeneration. Methods: Guided by a working group of experts, this prospective process entailed a series of stages that consisted of reviewing and assessing past grading schemes, surveying IVD researchers globally on current practice and recommendations for a new grading system, utilizing expert opinion a taxonomy of histological grading was developed, and validation performed. Results: A standardized taxonomy was developed, which showed excellent intra‐rater reliability for scoring nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous end plate (CEP) regions (interclass correlation [ICC] > .89). The ability to reliably detect subtle changes varied by IVD region, being poorest in the NP (ICC: .89‐.95) where changes at the cellular level were important, vs the AF (ICC: .93‐.98), CEP (ICC: .97‐.98), and boney end plate (ICC: .96‐.99) where matrix and structural changes varied more dramatically with degeneration. Conclusions: The proposed grading system incorporates more comprehensive descriptions of degenerative features for all the IVD sub‐tissues than prior criteria. While there was excellent reliability, our results reinforce the need for improved training, particularly for novice raters. Future evaluation of the proposed system in real‐world settings (eg, at the microscope) will be needed to further refine criteria and more fully evaluate utility. This improved taxonomy could aid in the understanding of IVD degeneration phenotypes and their association with back pain
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