777 research outputs found
Development of an in situ polymeric hydrogel implant of methylprednisolone for spinal injuries
Purpose: To prepare and characterize in situ gel-forming implants of methylprednisolone for the treatment of spinal cord injuries.Methods: In situ hydrogels of methylprednisolone were prepared by dispersing polylactide glycolic acid (PLGA) polymer and methylprednisolone in N-methyl-pyrrolidone solvent, and subsequent membrane sterilization. Hydrogels were prepared using varying concentrations of PLGA polymer. The physicochemical properties of hydrogels, including visual appearance, clarity, pH, viscosity, drug content, and in vitro drug release, were characterized. In vivo studies were performed to examine antiinflammatory activity (paw edema test) and in vivo motor function activity in a rat spinal injury model after injecting the hydrogels into rats.Results: The physicochemical properties of the gels were satisfactory. F1, F2, F3, and F4 formulations showed 99.67, 95.29, 88.89 and 88.20 % drug release, respectively, at the end of 7 days. In vivo antiinflammatory activity was highest for F1 (62.85 %). Motor function activity scores (arbitrary scale) for the F1, F2, F3 and F4 formulations were 4.82 ± 0.12, 4.70 ± 0.12, 4.68 ± 0.02, and 4.60 ± 0.05, respectively, and were higher (p < 0.05) for F1, F2 and F3) than for the standard (methylprednisolone, 30 mg/kg body weight, iv; activity score, 4.59 ± 0.20).Conclusions: The in situ hydrogels of methylprednisolone developed may be useful for the effective management of spinal cord injuries in patients. However, further investigations are required to ascertain their suitability for clinical use.Keywords: Methylprednisolone, In situ hydrogel, Spinal injury, Motor activity, Implan
Chrion: Optimizing Recurrent Neural Network Inference by Collaboratively Utilizing CPUs and GPUs
Deploying deep learning models in cloud clusters provides efficient and
prompt inference services to accommodate the widespread application of deep
learning. These clusters are usually equipped with host CPUs and accelerators
with distinct responsibilities to handle serving requests, i.e. generalpurpose
CPUs for input preprocessing and domain-specific GPUs for forward computation.
Recurrent neural networks play an essential role in handling temporal inputs
and display distinctive computation characteristics because of their high
inter-operator parallelism. Hence, we propose Chrion to optimize recurrent
neural network inference by collaboratively utilizing CPUs and GPUs. We
formulate the model deployment in the CPU-GPU cluster as an NP-hard scheduling
problem of directed acyclic graphs on heterogeneous devices. Given an input
model in the ONNX format and user-defined SLO requirement, Chrion firstly
preprocesses the model by model parsing and profiling, and then partitions the
graph to select execution devices for each operator. When an online request
arrives, Chrion performs forward computation according to the graph partition
by executing the operators on the CPU and GPU in parallel. Our experimental
results show that the execution time can be reduced by 19.4% at most in the
latency-optimal pattern and GPU memory footprint by 67.5% in the memory-optimal
pattern compared with the execution on the GPU
FedALA: Adaptive Local Aggregation for Personalized Federated Learning
A key challenge in federated learning (FL) is the statistical heterogeneity
that impairs the generalization of the global model on each client. To address
this, we propose a method Federated learning with Adaptive Local Aggregation
(FedALA) by capturing the desired information in the global model for client
models in personalized FL. The key component of FedALA is an Adaptive Local
Aggregation (ALA) module, which can adaptively aggregate the downloaded global
model and local model towards the local objective on each client to initialize
the local model before training in each iteration. To evaluate the
effectiveness of FedALA, we conduct extensive experiments with five benchmark
datasets in computer vision and natural language processing domains. FedALA
outperforms eleven state-of-the-art baselines by up to 3.27% in test accuracy.
Furthermore, we also apply ALA module to other federated learning methods and
achieve up to 24.19% improvement in test accuracy.Comment: Accepted by AAAI 202
Hepatitis B virus infection and replication in a new cell culture system established by fusing HepG2 cells with primary human hepatocytes
BackgroundHepatitis B virus (HBV) infection is strictly species and tissue specific, therefore none of the cell models established previously can reproduce the natural infection process of HBV in vitro. The aim of this study was to establish a new cell line that is susceptible to HBV and can support the replication of HBV.MethodsA hybrid cell line was established by fusing primary human hepatocytes with HepG2 cells. The hybrid cells were incubated with HBV-positive serum for 12 hours. HBV DNA was detected by quantitative fluorescence polymerase chain reaction (QF-PCR). HBsAg (surface antigen) and HBeAg (extracellular form of core antigen) were observed by electrochemiluminescence (ECL). HBcAg (core antigen) was detected by the indirect immunofluorescence technique. HBV covalently closed circular DNA (cccDNA) was analyzed by Southern blot hybridization and quantified using real-time PCR.ResultsA new cell line was established and named HepCHLine-7. The extracellular HBV DNA was observed from Day 2 and the levels ranged from 9.80 (± 0.32) × 102 copies/mL to 3.12 (± 0.03) × 104 copies/mL. Intracellular HBV DNA was detected at Day 2 after infection and the levels ranged from 7.92 (± 1.08) × 103 copies/mL to 5.63 (± 0.11) × 105 copies/mL. HBsAg in the culture medium was detected from Day 4 to Day 20. HBeAg secretion was positive from Day 5 to Day 20. HBcAg constantly showed positive signals in approximately 20% (± 0.82%) of hybrid cells. Intracellular HBV cccDNA could be detected as early as 2 days postinfection and the highest level was 15.76 (± 0.26) copies/cell.ConclusionHepCHLine-7 cells were susceptible to HBV and supported the replication of HBV. They are therefore suitable for studying the complete life cycle of HBV
FedCP: Separating Feature Information for Personalized Federated Learning via Conditional Policy
Recently, personalized federated learning (pFL) has attracted increasing
attention in privacy protection, collaborative learning, and tackling
statistical heterogeneity among clients, e.g., hospitals, mobile smartphones,
etc. Most existing pFL methods focus on exploiting the global information and
personalized information in the client-level model parameters while neglecting
that data is the source of these two kinds of information. To address this, we
propose the Federated Conditional Policy (FedCP) method, which generates a
conditional policy for each sample to separate the global information and
personalized information in its features and then processes them by a global
head and a personalized head, respectively. FedCP is more fine-grained to
consider personalization in a sample-specific manner than existing pFL methods.
Extensive experiments in computer vision and natural language processing
domains show that FedCP outperforms eleven state-of-the-art methods by up to
6.69%. Furthermore, FedCP maintains its superiority when some clients
accidentally drop out, which frequently happens in mobile settings. Our code is
public at https://github.com/TsingZ0/FedCP.Comment: Accepted by KDD 202
Seroconversion to Pandemic (H1N1) 2009 Virus and Cross-Reactive Immunity to Other Swine Influenza Viruses
To assess herd immunity to swine influenza viruses, we determined antibodies in 28 paired serum samples from participants in a prospective serologic cohort study in Hong Kong who had seroconverted to pandemic (H1N1) 2009 virus. Results indicated that infection with pandemic (H1N1) 2009 broadens cross-reactive immunity to other recent subtype H1 swine viruses
GPFL: Simultaneously Learning Global and Personalized Feature Information for Personalized Federated Learning
Federated Learning (FL) is popular for its privacy-preserving and
collaborative learning capabilities. Recently, personalized FL (pFL) has
received attention for its ability to address statistical heterogeneity and
achieve personalization in FL. However, from the perspective of feature
extraction, most existing pFL methods only focus on extracting global or
personalized feature information during local training, which fails to meet the
collaborative learning and personalization goals of pFL. To address this, we
propose a new pFL method, named GPFL, to simultaneously learn global and
personalized feature information on each client. We conduct extensive
experiments on six datasets in three statistically heterogeneous settings and
show the superiority of GPFL over ten state-of-the-art methods regarding
effectiveness, scalability, fairness, stability, and privacy. Besides, GPFL
mitigates overfitting and outperforms the baselines by up to 8.99% in accuracy.Comment: Accepted by ICCV202
Eliminating Domain Bias for Federated Learning in Representation Space
Recently, federated learning (FL) is popular for its privacy-preserving and
collaborative learning abilities. However, under statistically heterogeneous
scenarios, we observe that biased data domains on clients cause a
representation bias phenomenon and further degenerate generic representations
during local training, i.e., the representation degeneration phenomenon. To
address these issues, we propose a general framework Domain Bias Eliminator
(DBE) for FL. Our theoretical analysis reveals that DBE can promote
bi-directional knowledge transfer between server and client, as it reduces the
domain discrepancy between server and client in representation space. Besides,
extensive experiments on four datasets show that DBE can greatly improve
existing FL methods in both generalization and personalization abilities. The
DBE-equipped FL method can outperform ten state-of-the-art personalized FL
methods by a large margin. Our code is public at
https://github.com/TsingZ0/DBE.Comment: Accepted by NeurIPS 2023, 24 page
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