93 research outputs found
How to coadd images: II. Anti-aliasing and PSF deconvolution
We have developed a novel method for co-adding multiple under-sampled images
that combines the iteratively reweighted least squares and divide-and-conquer
algorithms. Our approach not only allows for the anti-aliasing of the images
but also enables PSF deconvolution, resulting in enhanced restoration of
extended sources, the highest PSNR, and reduced ringing artefacts. To test our
method, we conducted numerical simulations that replicated observation runs of
the CSST/VST telescope and compared our results to those obtained using
previous algorithms. The simulation showed that our method outperforms previous
approaches in several ways, such as restoring the profile of extended sources
and minimizing ringing artefacts. Additionally, because our method relies on
the inherent advantages of least squares fitting, it is more versatile and does
not depend on the local uniformity hypothesis for the PSF. However, the new
method consumes much more computation than the other approaches.Comment: 16 pages, 5 figures, 2 tables, accepted for publishing on RA
Cochlear Gene Therapy for Sensorineural Hearing Loss: Current Status and Major Remaining Hurdles for Translational Success
Sensorineural hearing loss (SNHL) affects millions of people. Genetic mutations play a large and direct role in both congenital and late-onset cases of SNHL (e.g., age-dependent hearing loss, ADHL). Although hearing aids can help moderate to severe hearing loss the only effective treatment for deaf patients is the cochlear implant (CI). Gene- and cell-based therapies potentially may preserve or restore hearing with more natural sound perception, since their theoretical frequency resolution power is much higher than that of cochlear implants. These biologically-based interventions also carry the potential to re-establish hearing without the need for implanting any prosthetic device; the convenience and lower financial burden afforded by such biologically-based interventions could potentially benefit far more SNHL patients. Recently major progress has been achieved in preclinical studies of cochlear gene therapy. This review critically evaluates recent advances in the preclinical trials of gene therapies for SNHL and the major remaining challenges for the development and eventual clinical translation of this novel therapy. The cochlea bears many similarities to the eye for translational studies of gene therapies. Experience gained in ocular gene therapy trials, many of which have advanced to clinical phase III, may provide valuable guidance in improving the chance of success for cochlear gene therapy in human trials. A discussion on potential implications of translational knowledge gleaned from large numbers of advanced clinical trials of ocular gene therapy is therefore included
Construction and validation of a nomogram of risk factors for new-onset atrial fibrillation in advanced lung cancer patients after non-surgical therapy
ObjectiveRisk factors of new-onset atrial fibrillation (NOAF) in advanced lung cancer patients are not well defined. We aim to construct and validate a nomogram model between NOAF and advanced lung cancer.MethodsWe retrospectively enrolled 19484 patients with Stage III-IV lung cancer undergoing first-line antitumor therapy in Shanghai Chest Hospital between January 2016 and December 2020 (15837 in training set, and 3647 in testing set). Patients with pre-existing AF, valvular heart disease, cardiomyopathy were excluded. Logistic regression analysis and propensity score matching (PSM) were performed to identify predictors of NOAF, and nomogram model was constructed and validated.ResultsA total of 1089 patients were included in this study (807 in the training set, and 282 in the testing set). Multivariate logistic regression analysis showed that age, c-reactive protein, centric pulmonary carcinoma, and pericardial effusion were independent risk factors, the last two of which were important independent risk factors as confirmed by PSM analysis. Nomogram included independent risk factors of age, c-reactive protein, centric pulmonary carcinoma, and pericardial effusion. The AUC was 0.716 (95% CI 0.661–0.770) and further evaluation of this model showed that the C-index was 0.716, while the bias-corrected C-index after internal validation was 0.748 in the training set. The calibration curves presented good concordance between the predicted and actual outcomes.ConclusionCentric pulmonary carcinoma and pericardial effusion were important independent risk factors for NOAF besides common ones in advanced lung cancer patients. Furthermore, the new nomogram model contributed to the prediction of NOAF
A self-assembled leucine polymer sensitizes leukemic stem cells to chemotherapy by inhibiting autophagy in acute myeloid leukemia
Chemotherapy is the primary treatment option for acute myeloid leukemia (AML), but leukemic stem cells (LSC) can survive chemotherapy for disease recurrence and refractory. Here, we found that AML cells obtained from relapsed patients had increased autophagy levels than de novo AML cells. Furthermore, doxorubicin (DOX) treatment stimulated autophagy in LSC by repressing the mTOR pathway, and pharmaceutical inhibition of autophagy rendered chemoresistant LSC sensitive to DOX treatment in MLL-AF9 induced murine AML. Moreover, we developed a self-assembled leucine polymer, which activated mTOR to inhibit autophagy in AML cells by releasing leucine. The leucine polymer loaded DOX (Leu-DOX) induced much less autophagy but more robust apoptosis in AML cells than the DOX treatment. Notably, the leucine polymer and Leu-DOX were specifically taken up by AML cells and LSC but not by normal hematopoietic cells and hematopoietic stem/progenitor cells in the bone marrow. Consequently, Leu-DOX efficiently reduced LSC and prolonged the survival of AML mice, with more limited myeloablation and tissue damage side effects than DOX treatment. Overall, we proposed that the newly developed Leu-DOX is an effective autophagy inhibitor and an ideal drug to efficiently eliminate LSC, thus serving as a revolutionary strategy to enhance the chemotherapy efficacy in AML
Inferring causal molecular networks: empirical assessment through a community-based effort
Inferring molecular networks is a central challenge in computational biology. However, it has remained unclear whether causal, rather than merely correlational, relationships can be effectively inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge that focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results constitute the most comprehensive assessment of causal network inference in a mammalian setting carried out to date and suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess the causal validity of inferred molecular networks
Inferring causal molecular networks: empirical assessment through a community-based effort
It remains unclear whether causal, rather than merely correlational, relationships in molecular networks can be inferred in complex biological settings. Here we describe the HPN-DREAM network inference challenge, which focused on learning causal influences in signaling networks. We used phosphoprotein data from cancer cell lines as well as in silico data from a nonlinear dynamical model. Using the phosphoprotein data, we scored more than 2,000 networks submitted by challenge participants. The networks spanned 32 biological contexts and were scored in terms of causal validity with respect to unseen interventional data. A number of approaches were effective, and incorporating known biology was generally advantageous. Additional sub-challenges considered time-course prediction and visualization. Our results suggest that learning causal relationships may be feasible in complex settings such as disease states. Furthermore, our scoring approach provides a practical way to empirically assess inferred molecular networks in a causal sense
A new technique to prevent conjunctival prolapse in Asian patients for correcting severe blepharoptosis
Abstract Background In Asian patients with severe ptosis,the use of conjoint fascia sheath (CFS) suspension or levator aponeurosis fascia complex shortening surgery can correct the ptosis. During these surgery, a significant amount of levator aponeurosis fascia shortening is performed, which often leads to serious complications such as conjunctival prolapse.This study compares two surgical approaches for correcting severe blepharoptosis:Conjoint fascial sheath (CFS) + levator aponeurosis and muller’s muscle complex (LM complex) suspension and conjoint fascial sheath (CFS) + LM complex+conjunctival suspension.The postoperative efficacy and the incidence of complications such as conjunctival prolapse are investigated for both procedures. Methods This study retrospectively analyzed 70 patients (77eyes) with severe blepharoptosis from January 2019 to December 2021. The patients were divided into the experimental group (34 cases, 38 eyes) and the control group (36 cases, 39 eyes). The experimental group was treated with CFS+LM complex + conjunctival suspension, and the control group was treated with CFS+LM complex suspension.The curative effect of blepharoptosis, the incidence of complications such as conjunctival prolapse and patient satisfaction were compared between the two different surgical methods. Results There was no significant difference in the correction effective rate between the experimental group (84.21%) and the control group (82.05%) (P > 0.05). There was no significant difference in the total incidence of complications between the experimental group (23.68%) and the control group (38.46%) (P > 0.05), but in the complication of conjunctival prolapse, the incidence of conjunctival prolapse in the experimental group was significantly lower than that in the control group. The difference was statistically significant (P < 0.05). In the survey of patient satisfaction rate, the satisfaction rate of the experimental group was significantly higher than that of the control group,which was statistically significant (P < 0.05). Conclusions Compared to CFS+LM complex suspension surgery, the CFS+LM complex + conjunctival suspension has a definite effect in preventing postoperative conjunctival prolapse .The procedure has a high feasibility, good corrective effect, and improves patient satisfaction after surgery
Ursolic Acid Attenuates Atherosclerosis in ApoE−/− Mice: Role of LOX-1 Mediated by ROS/NF-κB Pathway
Atherosclerosis, a chronic inflammatory disease, is a major contributor to cardiovascular diseases. Ursolic acid (UA) is a phytonutrient with widely biological effects including anti-oxidative, anti-inflammatory, and so on. At present, the effect of UA on atherosclerosis and the mechanism of action are still obscure. This study focused on investigating the effects of UA on atherosclerosis both in vivo and in vitro. We first selected LOX-1 as our target, which was reckoned as a new promising receptor for treating atherosclerosis. The evaluation in vitro suggested that UA significantly decreased endothelial LOX-1 expression induced by LPS both in mRNA and protein levels. Pre-treatment of UA also inhibited TLR4/MyD88 signaling activated by LPS. Moreover, UA reduced ROS production and suppressed the activation of NF-κB stimulated by LPS. Particularly, the evaluation in vivo further verified the conclusion obtained in vitro. In ApoE−/− mice fed with an atherogenic diet, both UA (100 mg/kg/day) and simvastatin significantly attenuated atherosclerotic plaque formation and shrunk necrotic core areas. The enhanced expression of LOX-1 in atherosclerotic aorta was also dramatically decreased by administration of UA. Taken together, these results suggested that UA, with anti-atherosclerotic activity through inhibition of LOX-1 mediated by ROS/NF-κB signaling pathways, may become a valuable vascular protective candidate for the treatment of atherosclerosis
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