323 research outputs found

    Aspects of Fractional Superstrings

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    We investigate some issues relating to recently proposed fractional superstring theories with Dcritical<10D_{\rm critical}<10. Using the factorization approach of Gepner and Qiu, we systematically rederive the partition functions of the K=4,8,K=4,\, 8, and 1616 theories and examine their spacetime supersymmetry. Generalized GSO projection operators for the K=4K=4 model are found. Uniqueness of the twist field, ϕK/4K/4\phi^{K/4}_{K/4}, as source of spacetime fermions is demonstrated. Last, we derive a linear (rather than quadratic) relationship between the required conformal anomaly and the conformal dimension of the supercurrent ghost.Comment: 36 pages, CALT-68-1756 Revisions to match form to appear in Comm. Math. Phys. Use standard TeX. Derivation of affine partition functions related to D=4,6D=4,6 models is now shown. References Update

    Predictors of undergoing multivisceral resection, margin status and survival in Dutch patients with locally advanced colorectal cancer

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    Background: The aim of this nationwide observational study was to evaluate factors associated with multivisceral resection (MVR), margin status and overall survival in locally advanced colorectal cancer (CRC). Material and methods: Patients with (y)pT4, cM0 CRC between 2006 and 2017 were selected from the Netherlands Cancer Registry. Cox-proportional hazards modelling was used for survival analysis, stratified for T4a and T4b. Annual hospital volume cut-off was 75 for colon and 40 for rectal resections. Results: A total of 11.930 patients were included and 2410 patients (20.2%) underwent MVR. Factors associated with MVR for colon and rectal cancer besides cT4 category were more recent diagnosis (OR 3.61, CI 95% 3.06–4.25 (colon) and OR 2.72, CI 95% 1.82–4.08 (rectum)) and high hospital volume (OR 1.20, CI 95% 1.05–1.38 (colon) and OR 2.17, CI 95% 1.55–3.04 (rectum)). Patients ≥70 year were less likely to undergo MVR for colon cancer (OR 0.80, 95% CI 0.70–0.90). Risk factors for incomplete resection were cT4 (OR 3.08, CI 95% 2.35–4.04 (colon) and OR 1.82, CI 95% 1.13–2.94 (rectum)) and poor/undifferentiated tumors (OR 1.41, CI 95% 1.14–1.72 (colon) and OR 1.69, CI 95% 1.05–2.74 (rectum)). More recent diagnosis was independently associated with less incomplete resections in colon cancer (OR 0.58, CI 95% 0.40–0.76). Independent predictors of survival were age, resection margin, nodal status and adjuvant chemotherapy, but not MVR. Conclusion: Treatment of locally advanced CRC with MVR at population level was influenced by year of diagnosis and hospital volume. Margin status in colon cancer improved substantially over time.</p

    Predictors of undergoing multivisceral resection, margin status and survival in Dutch patients with locally advanced colorectal cancer

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    Background: The aim of this nationwide observational study was to evaluate factors associated with multivisceral resection (MVR), margin status and overall survival in locally advanced colorectal cancer (CRC). Material and methods: Patients with (y)pT4, cM0 CRC between 2006 and 2017 were selected from the Netherlands Cancer Registry. Cox-proportional hazards modelling was used for survival analysis, stratified for T4a and T4b. Annual hospital volume cut-off was 75 for colon and 40 for rectal resections. Results: A total of 11.930 patients were included and 2410 patients (20.2%) underwent MVR. Factors associated with MVR for colon and rectal cancer besides cT4 category were more recent diagnosis (OR 3.61, CI 95% 3.06–4.25 (colon) and OR 2.72, CI 95% 1.82–4.08 (rectum)) and high hospital volume (OR 1.20, CI 95% 1.05–1.38 (colon) and OR 2.17, CI 95% 1.55–3.04 (rectum)). Patients ≥70 year were less likely to undergo MVR for colon cancer (OR 0.80, 95% CI 0.70–0.90). Risk factors for incomplete resection were cT4 (OR 3.08, CI 95% 2.35–4.04 (colon) and OR 1.82, CI 95% 1.13–2.94 (rectum)) and poor/undifferentiated tumors (OR 1.41, CI 95% 1.14–1.72 (colon) and OR 1.69, CI 95% 1.05–2.74 (rectum)). More recent diagnosis was independently associated with less incomplete resections in colon cancer (OR 0.58, CI 95% 0.40–0.76). Independent predictors of survival were age, resection margin, nodal status and adjuvant chemotherapy, but not MVR. Conclusion: Treatment of locally advanced CRC with MVR at population level was influenced by year of diagnosis and hospital volume. Margin status in colon cancer improved substantially over time.</p

    Salvage surgery for local failures after stereotactic ablative radiotherapy for early stage non-small cell lung cancer

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    markdownabstract__Introduction:__ The literature on surgical salvage, i.e. lung resections in patients who develop a local recurrence following stereotactic ablative radiotherapy (SABR), is limited. We describe our experience with salvage surgery in nine patients who developed a local recurrence following SABR for early stage non-small cell lung cancer (NSCLC). __Methods:__ Patients who underwent surgical salvage for a local recurrence following SABR for NSCLC were identified from two Dutch institutional databases. Complications were scored using the Dindo-Clavien-classification. __Results:__ Nine patients who underwent surgery for a local recurrence were identified. Median time to local recurrence was 22 months. Recurrences were diagnosed with CT- and/or 18FDG-PET-imaging, with four patients also having a pre-surgical pathological diagnosis. Extensive adhesions were observed during two resections, requiring conversion from a thoracoscopic procedure to thoracotomy during one of these procedures. Three patients experienced complications post-surgery; grade 2 (N = 2) and grade 3a (N = 1), respectively. All resection specimens showed viable tumor cells. Median length of hospital stay was 8 days (range 5-15 days) and 30-day mortality was 0 %. Lymph node dissection revealed mediastinal metastases in 3 patients, all of whom received adjuvant therapy. __Conclusions:__ Our experience with nine surgical procedures for local recurrences post-SABR revealed two grade IIIa complications, and a 30-day mortality of 0 %, suggesting that salvage surgery can be safely performed after SABR

    One Spin Trace Formalism for BK B_K

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    It has been known for some time that there are two methods to calculate BK B_K with staggered fermions: one is the two spin trace formalism and the other is the one spin trace formalism. Until now, the two spin trace formalism has been exclusively used for weak matrix element calculations with staggered fermions. Here, the one spin trace formalism to calculate BK B_K with staggered fermions is explained. It is shown that the one spin trace operators require additional chiral partner operators in order to keep the continuum chiral behavior. The renormalization of the one spin trace operators is described and compared with the two spin trace formalism.Comment: 47 pages, latex, 4 figures are available on reques

    Automorphism Modular Invariants of Current Algebras

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    We consider those two-dimensional rational conformal field theories (RCFTs) whose chiral algebras, when maximally extended, are isomorphic to the current algebra formed from some affine non-twisted Kac--Moody algebra at fixed level. In this case the partition function is specified by an automorphism of the fusion ring and corresponding symmetry of the Kac--Peterson modular matrices. We classify all such partition functions when the underlying finite-dimensional Lie algebra is simple. This gives all possible spectra for this class of RCFTs. While accomplishing this, we also find the primary fields with second smallest quantum dimension.Comment: 32 pages, plain Te

    The potential and limitations of intrahepatic cholangiocyte organoids to study inborn errors of metabolism

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    Inborn errors of metabolism (IEMs) comprise a diverse group of individually rare monogenic disorders that affect metabolic pathways. Mutations lead to enzymatic deficiency or dysfunction, which results in intermediate metabolite accumulation or deficit leading to disease phenotypes. Currently, treatment options for many IEMs are insufficient. Rarity of individual IEMs hampers therapy development and phenotypic and genetic heterogeneity suggest beneficial effects of personalized approaches. Recently, cultures of patient-own liver-derived intrahepatic cholangiocyte organoids (ICOs) have been established. Since most metabolic genes are expressed in the liver, patient-derived ICOs represent exciting possibilities for in vitro modeling and personalized drug testing for IEMs. However, the exact application range of ICOs remains unclear. To address this, we examined which metabolic pathways can be studied with ICOs and what the potential and limitations of patient-derived ICOs are to model metabolic functions. We present functional assays in patient ICOs with defects in branched-chain amino acid metabolism (methylmalonic acidemia), copper metabolism (Wilson disease), and transporter defects (cystic fibrosis). We discuss the broad range of functional assays that can be applied to ICOs, but also address the limitations of these patient-specific cell models. In doing so, we aim to guide the selection of the appropriate cell model for studies of a specific disease or metabolic process

    Long-term evidence for ecological intensification as a pathway to sustainable agriculture

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    Ecological intensification (EI) could help return agriculture into a ‘safe operating space’ for humanity. Using a novel application of meta-analysis to data from 30 long-term experiments from Europe and Africa (comprising 25,565 yield records), we investigated how field-scale EI practices interact with each other, and with N fertilizer and tillage, in their effects on long-term crop yields. Here we confirmed that EI practices (specifically, increasing crop diversity and adding fertility crops and organic matter) have generally positive effects on the yield of staple crops. However, we show that EI practices have a largely substitutive interaction with N fertilizer, so that EI practices substantially increase yield at low N fertilizer doses but have minimal or no effect on yield at high N fertilizer doses. EI practices had comparable effects across different tillage intensities, and reducing tillage did not strongly affect yields

    Human B Cells Engage the NCK/PI3K/RAC1 Axis to Internalize Large Particles via the IgM-BCR

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    Growing evidence indicate that large antigen-containing particles induce potent T cell-dependent high-affinity antibody responses. These responses require large particle internalization after recognition by the B cell receptor (BCR) on B cells. However, the molecular mechanisms governing BCR-mediated internalization remain unclear. Here we use a high-throughput quantitative image analysis approach to discriminate between B cell particle binding and internalization. We systematically show, using small molecule inhibitors, that human B cells require a SYK-dependent IgM-BCR signaling transduction via PI3K to efficiently internalize large anti-IgM-coated particles. IgM-BCR-mediated activation of PI3K involves both the adaptor protein NCK and the co-receptor CD19. Interestingly, we here reveal a strong NCK-dependence without profound requirement of the co-receptor CD19 in B cell responses to large particles. Furthermore, we demonstrate that the IgM-BCR/NCK signaling event facilitates RAC1 activation to promote actin cytoskeleton remodeling necessary for particle engulfment. Thus, we establish NCK/PI3K/RAC1 as an attractive IgM-BCR signaling axis for biological intervention to prevent undesired antibody responses to large particles

    Randomized Clinical-Trial of Manipulative Therapy and Physiotherapy for Persistent Back and Neck Complaints - Results of One Year Follow-Up

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    Objective - To compare the effectiveness of manipulative therapy, physiotherapy, treatment by the general practitioner, and placebo therapy in patients with persistent non-specific back and neck complaints. Design - Randomised clinical trial. Setting-Primary health care in the Netherlands. Patients-256 patients with non-specific back and neck complaints of at least six weeks' duration who had not received physiotherapy or manipulative therapy in the past two years. Interventions - At the discretion of the manipulative therapists, physiotherapists, and general practitioners. Physiotherapy consisted of exercises, massage, and physical therapy (heat, electrotherapy, ultrasound, shortwave diathermy). Manipulative therapy consisted of manipulation and mobilisation of the spine. Treatment by general practitioners consisted of drugs (for example, analgesics), advice about posture, home exercises, and (bed)rest. Placebo treatment consisted of detuned shortwave diathermy (10 minutes) and detuned ultrasound (10 minutes). Main outcome measures - Changes in severity of the main complaint and limitation of physical functioning measured on 10 point scales by a blinded research assistant and global perceived effect measured on a 6 point scale by the patients. Results - Many patients in the general practitioner and placebo groups received other treatment during follow up. Improvement in the main complaint was larger with manipulative therapy (4·5) than with physiotherapy (3·8) after 12 months' follow up (difference 0·9; 95% confidence interval 0·1 to 1·7). Manipulative therapy also gave larger improvements in physical functioning (difference 0·6; -0·1 to 1·3). The global perceived effect after six and 12 months' follow up was similar for both treatments. Conclusions - Manipulative therapy and physiotherapy are better than general practitioner and placebo treatment. Furthermore, manipulative therapy is slightly better than physiotherapy after 12 months
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