Distributed Graph Neural Network Training: A Survey

Graph neural networks (GNNs) are a type of deep learning models that are trained on graphs and have been successfully applied in various domains. Despite the effectiveness of GNNs, it is still challenging for GNNs to efficiently scale to large graphs. As a remedy, distributed computing becomes a promising solution of training large-scale GNNs, since it is able to provide abundant computing resources. However, the dependency of graph structure increases the difficulty of achieving high-efficiency distributed GNN training, which suffers from the massive communication and workload imbalance. In recent years, many efforts have been made on distributed GNN training, and an array of training algorithms and systems have been proposed. Yet, there is a lack of systematic review on the optimization techniques for the distributed execution of GNN training. In this survey, we analyze three major challenges in distributed GNN training that are massive feature communication, the loss of model accuracy and workload imbalance. Then we introduce a new taxonomy for the optimization techniques in distributed GNN training that address the above challenges. The new taxonomy classifies existing techniques into four categories that are GNN data partition, GNN batch generation, GNN execution model, and GNN communication protocol. We carefully discuss the techniques in each category. In the end, we summarize existing distributed GNN systems for multi-GPUs, GPU-clusters and CPU-clusters, respectively, and give a discussion about the future direction on distributed GNN training

A review of slicing methods for directed energy deposition based additive manufacturing

Purpose: The purpose of this paper is to systematically review the published slicing methods for additive manufacturing (AM), especially the multi-direction and non-layerwise slicing methods, which are particularly suitable for the directed energy deposition (DED) process to improve the surface quality and eliminate the usage of support structures. Design/methodology/approach: In this paper, the published slicing methods are clarified into three categories: the traditional slicing methods (e.g. the basic and adaptive slicing methods) performed in the powder bed fusion (PBF) system, the multi-direction slicing methods and non-layerwise slicing methods used in DED systems. The traditional slicing methods are reviewed only briefly because a review article already exists for them, and the latter two slicing methods are reviewed comprehensively with further discussion and outlook. Findings: A few traditional slicing approaches were developed in the literature, including basic and adaptive slicing methods. These methods are efficient and robust when they are performed in the PBF system. However, they are retarded in the DED process because costly support structures are required to sustain overhanging parts and their surface quality and contour accuracy are not satisfactory. This limitation has led to the development of various multi-direction and non-layerwise slicing methods to improve the surface quality and enable the production of overhangs with minimum supports. Originality/value: An original review of the AM slicing methods is provided in this paper. For the traditional slicing methods and the multi-direction and non-layerwise slicing method, the published slicing strategies are discussed and compared. Recommendations for future slicing work are also provided

A Flow-Through Reaction Cell for Studying Minerals Leaching by In-Situ Synchrotron Powder X-ray Diffraction

A flow-through reaction cell has been developed for studying minerals leaching by in-situ time-resolved powder X-ray diffraction, allowing for a better understanding of the leaching mechanisms and kinetics. The cell has the capability of independent control of temperature (up to 95 °C) and flow rate (>0.5 mL min−1) for atmospheric pressure leaching. It was successfully tested at the powder diffraction beamline at the Australian Synchrotron. Galena powder was leached in a citrate solution under flow-through condition at a flow rate of 0.5 mL min−1, while diffraction patterns were collected during the entire leaching process, showing rapid galena dissolution without the formation of secondary mineral phases. The flow-through cell can be used to study leaching processes of other ore minerals

Overexpression of AcEXPA23 Promotes Lateral Root Development in Kiwifruit

Kiwifruit is loved by consumers for its unique taste and rich vitamin C content. Kiwifruit are very sensitive to adverse soil environments owing to fleshy and shallow roots, which limits the uptake of water and nutrients into the root system, resulting in low yield and poor fruit quality. Lateral roots are the key organs for plants to absorb water and nutrients. Improving water and fertilizer use efficiency by promoting lateral root development is a feasible method to improve yield and quality. Expansin proteins plays a major role in lateral root growth; hence, it is important to identify expansin protein family members, screen key genes, and explore gene function in root development. In this study, 41 expansin genes were identified based on the genome of kiwifruit (‘Hongyang’, Actinidia chinensis). By clustering with the Arabidopsis thaliana expansin protein family, the 41 AcExpansin proteins were divided into four subfamilies. The AcExpansin protein family was further analysed by bioinformatics methods and was shown to be evolutionarily diverse and conserved at the DNA and protein levels. Based on previous transcriptome data and quantitative real-time PCR assays, we screened the candidate gene AcEXPA23. Overexpression of AcEXPA23 in kiwifruit increased the number of kiwifruit lateral roots

AvNAC030, a NAC Domain Transcription Factor, Enhances Salt Stress Tolerance in Kiwifruit

Kiwifruit (Actinidia chinensis Planch) is suitable for neutral acid soil. However, soil salinization is increasing in kiwifruit production areas, which has adverse effects on the growth and development of plants, leading to declining yields and quality. Therefore, analyzing the salt tolerance regulation mechanism can provide a theoretical basis for the industrial application and germplasm improvement of kiwifruit. We identified 120 NAC members and divided them into 13 subfamilies according to phylogenetic analysis. Subsequently, we conducted a comprehensive and systematic analysis based on the conserved motifs, key amino acid residues in the NAC domain, expression patterns, and protein interaction network predictions and screened the candidate gene AvNAC030. In order to study its function, we adopted the method of heterologous expression in Arabidopsis. Compared with the control, the overexpression plants had higher osmotic adjustment ability and improved antioxidant defense mechanism. These results suggest that AvNAC030 plays a positive role in the salt tolerance regulation mechanism in kiwifruit

Fabrication of Hydrogel with Cell Adhesive Micropatterns for Mimicking the Oriented Tumor-Associated Extracellular Matrix

For mimicking the fibrous extracellular matrix (ECM), a facile method for patterning anticell adhesive substrate was novelly applied on agarose hydrogel. Without using masks or templates for etching, we applied the magnetic field-induced colloidal assembly of magnetic nanoparticles on the flat agarose hydrogel to form cell-adhesive micropatterns. Meanwhile, tuning the hydrogel substrate’s modulus to fit real tissue was experimentally demonstrated. Magnetic nanobeads were also assembled on this hydrogel surface and formed more complete and regular patterns. The patterned hydrogel substrate could actually influence behaviors of different cancer cells, including adhesion, growth, and migration

A Phase Ib Study of Pembrolizumab as Second-Line Therapy for Chinese Patients With Advanced or Metastatic Melanoma (KEYNOTE-151)

Background: Pembrolizumab shows robust antitumor activity and favorable safety in metastatic melanoma. KEYNOTE-151 evaluated pembrolizumab in Chinese patients, who have more aggressive melanoma subtypes than other populations. Methods: Chinese patients aged ≥18 years with advanced melanoma previously treated with one line of therapy received pembrolizumab 2 mg/kg every 3 weeks for 35 cycles or until confirmed disease progression, intolerable toxicity, or study withdrawal. Primary end points were objective response rate (ORR) per RECIST v1.1 by blinded independent central review and safety. Key secondary end points included duration of response (DOR) and progression-free survival (PFS) per RECIST v1.1 and overall survival (OS). Results: Median age was 52 years (N = 103); 37.9% had acral and 14.6% had mucosal melanoma. Median follow-up was 7.9 months at data cutoff (December 27, 2017). ORR was 16.7% (95% CI, 10.0–25.3%) (1 complete, 16 partial responses). Disease control rate was 38.2%. ORR was 15.8% for acral, 13.3% for mucosal melanoma. Median DOR was 8.4 months; 65.6% of patients had response duration ≥6 months. Median PFS was 2.8 months (95% CI, 2.7–3.5 months); 6-month rate was 20.4%. Median OS was 12.1 months (95% CI, 9.6 months–not reached); 6-month rate, 75.7%; 12-month rate, 50.6%. Treatment-related AEs (TRAEs) occurred in 87 (84.5%) patients; 9 (8.7%) experienced grade 3/4 TRAE and 2 (1.9%) discontinued because of TRAE; none died. Two deaths occurred that were unrelated to treatment. Conclusions: Pembrolizumab was well tolerated and provided clinically meaningful antitumor activity as second-line therapy in Chinese patients with advanced melanoma