Topic: "nextflow"
nextflow-io/nextflow
A DSL for data-driven computational pipelines
Language: Groovy - Size: 62 MB - Last synced at: 1 day ago - Pushed at: 1 day ago - Stars: 3,207 - Forks: 747
nf-core/rnaseq
RNA sequencing analysis pipeline using STAR, RSEM, HISAT2 or Salmon with gene/isoform counts and extensive quality control.
Language: Nextflow - Size: 72.3 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 1,133 - Forks: 812
nextflow-io/awesome-nextflow
A curated list of nextflow based pipelines
Size: 180 KB - Last synced at: 10 days ago - Pushed at: 5 months ago - Stars: 609 - Forks: 93
nf-core/sarek
Analysis pipeline to detect germline or somatic variants (pre-processing, variant calling and annotation) from WGS / targeted sequencing
Language: Nextflow - Size: 113 MB - Last synced at: about 12 hours ago - Pushed at: about 13 hours ago - Stars: 502 - Forks: 491
bactopia/bactopia
A flexible pipeline for complete analysis of bacterial genomes
Language: Nextflow - Size: 49.8 MB - Last synced at: 11 days ago - Pushed at: 11 days ago - Stars: 481 - Forks: 77
nf-core/modules
Repository to host tool-specific module files for the Nextflow DSL2 community!
Language: Nextflow - Size: 165 MB - Last synced at: 4 days ago - Pushed at: 4 days ago - Stars: 386 - Forks: 933
nextflow-io/patterns
A curated collection of Nextflow implementation patterns
Language: Nextflow - Size: 2.4 MB - Last synced at: 9 months ago - Pushed at: almost 2 years ago - Stars: 342 - Forks: 70
nf-core/scrnaseq
Single-cell RNA-Seq pipeline for barcode-based protocols such as 10x, DropSeq or SmartSeq, offering a variety of aligners and empty-droplet detection
Language: Nextflow - Size: 43.7 MB - Last synced at: 19 days ago - Pushed at: 19 days ago - Stars: 296 - Forks: 203
nf-core/tools
Python package with helper tools for the nf-core community.
Language: Python - Size: 18.6 MB - Last synced at: 1 day ago - Pushed at: 1 day ago - Stars: 280 - Forks: 220
lynnlangit/gcp-for-bioinformatics
GCP for Bioinformatics Researchers
Language: Jupyter Notebook - Size: 89.9 MB - Last synced at: about 1 month ago - Pushed at: 6 months ago - Stars: 277 - Forks: 74
nf-core/mag
Assembly and binning of metagenomes
Language: Nextflow - Size: 42.3 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 251 - Forks: 142
assemblerflow/flowcraft
FlowCraft: a component-based pipeline composer for omics analysis using Nextflow. :whale::package:
Language: Python - Size: 7.89 MB - Last synced at: about 2 months ago - Pushed at: 3 months ago - Stars: 245 - Forks: 45
nvuillam/npm-groovy-lint
Lint, format and auto-fix your Groovy / Jenkinsfile / Gradle files using command line
Language: JavaScript - Size: 126 MB - Last synced at: 21 days ago - Pushed at: 21 days ago - Stars: 237 - Forks: 67
nf-core/ampliseq
Amplicon sequencing analysis workflow using DADA2 and QIIME2
Language: Nextflow - Size: 18.2 MB - Last synced at: 12 days ago - Pushed at: 12 days ago - Stars: 225 - Forks: 147
nf-core/chipseq
ChIP-seq peak-calling, QC and differential analysis pipeline.
Language: Nextflow - Size: 15.8 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 225 - Forks: 162
nf-core/atacseq
ATAC-seq peak-calling and QC analysis pipeline
Language: Nextflow - Size: 9.97 MB - Last synced at: 8 days ago - Pushed at: 8 days ago - Stars: 213 - Forks: 128
nf-core/nanoseq
Nanopore demultiplexing, QC and alignment pipeline
Language: Nextflow - Size: 6.92 MB - Last synced at: 2 months ago - Pushed at: 4 months ago - Stars: 209 - Forks: 100
nextflow-io/training
Nextflow training material
Language: Nextflow - Size: 394 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 195 - Forks: 255
nf-core/eager
A fully reproducible and state-of-the-art ancient DNA analysis pipeline
Language: Nextflow - Size: 64.9 MB - Last synced at: 5 days ago - Pushed at: 5 days ago - Stars: 186 - Forks: 86
nf-core/fetchngs
Pipeline to fetch metadata and raw FastQ files from public databases
Language: Nextflow - Size: 4.32 MB - Last synced at: 20 days ago - Pushed at: 21 days ago - Stars: 183 - Forks: 89
nf-core/methylseq
Methylation (Bisulfite-Sequencing) analysis pipeline using Bismark or bwa-meth + MethylDackel
Language: Nextflow - Size: 25.2 MB - Last synced at: 1 day ago - Pushed at: 1 day ago - Stars: 180 - Forks: 160
lynnlangit/aws-for-bioinformatics
AWS for Bioinformatics Researchers
Language: Jupyter Notebook - Size: 118 MB - Last synced at: about 1 month ago - Pushed at: 4 months ago - Stars: 180 - Forks: 42
askimed/nf-test
Simple test framework for Nextflow pipelines
Language: Java - Size: 5.91 MB - Last synced at: 16 days ago - Pushed at: 16 days ago - Stars: 173 - Forks: 37
nf-core/taxprofiler
Highly parallelised multi-taxonomic profiling of shotgun short- and long-read metagenomic data
Language: Nextflow - Size: 16.6 MB - Last synced at: 7 days ago - Pushed at: 7 days ago - Stars: 168 - Forks: 59
nf-core/rnafusion
RNA-seq analysis pipeline for detection of gene-fusions
Language: Nextflow - Size: 23.1 MB - Last synced at: about 8 hours ago - Pushed at: about 10 hours ago - Stars: 165 - Forks: 118
seqeralabs/nf-tower 📦
Nextflow Tower system
Language: Groovy - Size: 10.6 MB - Last synced at: 27 days ago - Pushed at: 10 months ago - Stars: 151 - Forks: 55
EBI-Metagenomics/emg-viral-pipeline
VIRify: detection of phages and eukaryotic viruses from metagenomic and metatranscriptomic assemblies
Language: Python - Size: 31 MB - Last synced at: 1 day ago - Pushed at: 1 day ago - Stars: 144 - Forks: 21
nf-core/viralrecon
Assembly and intrahost/low-frequency variant calling for viral samples
Language: Nextflow - Size: 11.4 MB - Last synced at: 12 days ago - Pushed at: 12 days ago - Stars: 144 - Forks: 139
PGScatalog/pgsc_calc
The Polygenic Score Catalog Calculator is a nextflow pipeline for polygenic score calculation
Language: Nextflow - Size: 11.3 MB - Last synced at: 2 months ago - Pushed at: 3 months ago - Stars: 143 - Forks: 31
nf-core/test-datasets
Test data to be used for automated testing with the nf-core pipelines
Size: 31 GB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 142 - Forks: 446
CRG-CNAG/CalliNGS-NF
GATK RNA-Seq Variant Calling in Nextflow
Language: Nextflow - Size: 29 MB - Last synced at: 6 months ago - Pushed at: almost 3 years ago - Stars: 133 - Forks: 53
SciLifeLab/Sarek Fork of nf-core/sarek 📦
Detect germline or somatic variants from normal or tumour/normal whole-genome or targeted sequencing
Language: Nextflow - Size: 43.8 MB - Last synced at: 8 months ago - Pushed at: almost 6 years ago - Stars: 133 - Forks: 7
dockstore/dockstore
An app store for scientific workflows, tools, notebooks, and services
Language: Java - Size: 41.6 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 130 - Forks: 29
nf-core/raredisease
Call and score variants from WGS/WES of rare disease patients.
Language: Nextflow - Size: 188 MB - Last synced at: 4 days ago - Pushed at: 4 days ago - Stars: 112 - Forks: 55
BastidaNicolas/nextauth-prisma-stripe
How to integrate subscriptions into your Next.js project (/app). The tutorial utilizes Next.js (v13.4) with the /app directory structure, NextAuth v4 for authentication, Prisma for database management, and Stripe for payment processing.
Language: TypeScript - Size: 163 KB - Last synced at: about 2 months ago - Pushed at: over 1 year ago - Stars: 109 - Forks: 17
stevekm/nextflow-demos
Example Nextflow pipelines and programming techniques
Language: Nextflow - Size: 13.5 MB - Last synced at: about 1 month ago - Pushed at: 2 months ago - Stars: 106 - Forks: 26
biocorecrg/master_of_pores
Nextflow pipeline for analysis of direct RNA Nanopore reads
Language: Nextflow - Size: 448 MB - Last synced at: 4 months ago - Pushed at: 5 months ago - Stars: 106 - Forks: 17
replikation/What_the_Phage
WtP: Phage identification via nextflow and docker or singularity
Language: Nextflow - Size: 41.1 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 105 - Forks: 15
nf-core/configs
Config files used to define parameters specific to compute environments at different Institutions
Language: Nextflow - Size: 47.3 MB - Last synced at: 7 days ago - Pushed at: 7 days ago - Stars: 104 - Forks: 335
nf-core/cutandrun
Analysis pipeline for CUT&RUN and CUT&TAG experiments that includes QC, support for spike-ins, IgG controls, peak calling and downstream analysis.
Language: Nextflow - Size: 8.81 MB - Last synced at: 29 days ago - Pushed at: 29 days ago - Stars: 103 - Forks: 62
fmalmeida/bacannot
Generic but comprehensive pipeline for prokaryotic genome annotation and interrogation with interactive reports and shiny app.
Language: Nextflow - Size: 50 MB - Last synced at: 2 months ago - Pushed at: 8 months ago - Stars: 103 - Forks: 10
nf-core/hic
Analysis of Chromosome Conformation Capture data (Hi-C)
Language: Nextflow - Size: 3.76 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 101 - Forks: 63
nf-core/pangenome
Renders a collection of sequences into a pangenome graph. https://doi.org/10.1093/bioinformatics/btae609.
Language: Nextflow - Size: 4.25 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 97 - Forks: 22
open2c/distiller-nf
A modular Hi-C mapping pipeline
Language: Groovy - Size: 1.33 MB - Last synced at: 4 months ago - Pushed at: 12 months ago - Stars: 97 - Forks: 26
nf-core/funcscan
(Meta-)genome screening for functional and natural product gene sequences
Language: Nextflow - Size: 27.4 MB - Last synced at: 7 days ago - Pushed at: 7 days ago - Stars: 94 - Forks: 34
nf-core/oncoanalyser
A comprehensive cancer DNA/RNA analysis and reporting pipeline
Language: Nextflow - Size: 6.86 MB - Last synced at: 7 days ago - Pushed at: 7 days ago - Stars: 92 - Forks: 27
nf-core/smrnaseq
A small-RNA sequencing analysis pipeline
Language: Nextflow - Size: 8.48 MB - Last synced at: 2 months ago - Pushed at: 6 months ago - Stars: 90 - Forks: 127
nf-core/proteinfold
Protein 3D structure prediction pipeline
Language: Nextflow - Size: 8.43 MB - Last synced at: 3 days ago - Pushed at: 3 days ago - Stars: 89 - Forks: 59
nf-core/differentialabundance
Differential abundance analysis for feature/ observation matrices from platforms such as RNA-seq
Language: Nextflow - Size: 10.3 MB - Last synced at: 7 days ago - Pushed at: 7 days ago - Stars: 84 - Forks: 57
nvuillam/vscode-groovy-lint
VSCode extension to lint , correct and format groovy and Jenkinsfile
Language: Groovy - Size: 18.7 MB - Last synced at: 8 days ago - Pushed at: 8 days ago - Stars: 83 - Forks: 18
likelet/LncPipe
A Nextflow-based pipeline for comprehensive analyses of long non-coding RNAs from RNA-seq datasets
Language: Groovy - Size: 5.78 MB - Last synced at: 7 months ago - Pushed at: about 3 years ago - Stars: 82 - Forks: 51
nf-core/website
Code and files for the main nf-core website.
Language: MDX - Size: 3.81 GB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 81 - Forks: 253
nextflow-io/rnaseq-nf
A proof of concept of RNAseq pipeline
Language: Nextflow - Size: 591 KB - Last synced at: 28 days ago - Pushed at: 28 days ago - Stars: 79 - Forks: 111
nf-core/bacass
Simple bacterial assembly and annotation pipeline
Language: Nextflow - Size: 5.3 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 78 - Forks: 64
gluonfield/nf-shard
Nextflow runs monitoring and organisation UI
Language: TypeScript - Size: 2.07 MB - Last synced at: 3 months ago - Pushed at: about 1 year ago - Stars: 77 - Forks: 13
genepi/nf-gwas
A nextflow pipeline to perform state-of-the-art genome-wide association studies.
Language: Nextflow - Size: 65.2 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 75 - Forks: 27
nf-core/hlatyping
Precision HLA typing from next-generation sequencing data
Language: Nextflow - Size: 39.4 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 73 - Forks: 33
icbi-lab/nextNEOpi
nextNEOpi: a comprehensive pipeline for computational neoantigen prediction
Language: Nextflow - Size: 5.41 MB - Last synced at: 6 months ago - Pushed at: 6 months ago - Stars: 73 - Forks: 25
danrlu/nextflow_cheatsheet
Tips for Nextflow and cheatsheet for channel operation
Size: 416 KB - Last synced at: 8 months ago - Pushed at: over 1 year ago - Stars: 73 - Forks: 10
nf-core/scdownstream
A single cell transcriptomics pipeline for QC, integration and making the data presentable
Language: Nextflow - Size: 3.44 MB - Last synced at: 2 months ago - Pushed at: 2 months ago - Stars: 71 - Forks: 38
LUMC/pytest-workflow
Configure workflow/pipeline tests using yaml files.
Language: Python - Size: 763 KB - Last synced at: about 1 month ago - Pushed at: over 1 year ago - Stars: 69 - Forks: 10
nf-core/spatialvi
Pipeline for processing spatially-resolved gene counts with spatial coordinates and image data. Designed for 10x Genomics Visium transcriptomics.
Language: Nextflow - Size: 7.24 MB - Last synced at: 4 days ago - Pushed at: 5 days ago - Stars: 67 - Forks: 28
nf-core/airrflow
B-cell and T-cell Adaptive Immune Receptor Repertoire (AIRR) sequencing analysis pipeline using the Immcantation framework
Language: Nextflow - Size: 13.9 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 66 - Forks: 45
goodwright/nextflow.py
Python wrapper around Nextflow.
Language: Python - Size: 331 KB - Last synced at: 18 days ago - Pushed at: 18 days ago - Stars: 60 - Forks: 7
nf-core/bactmap
A mapping-based pipeline for creating a phylogeny from bacterial whole genome sequences
Language: Nextflow - Size: 136 MB - Last synced at: 2 months ago - Pushed at: 2 months ago - Stars: 60 - Forks: 51
fmalmeida/MpGAP
Multi-platform genome assembly pipeline for Illumina, Nanopore and PacBio reads
Language: Nextflow - Size: 83.2 MB - Last synced at: 6 months ago - Pushed at: about 1 year ago - Stars: 59 - Forks: 11
brwnj/covviz
Multi-sample genome coverage viewer to observe large, coverage-based anomalies alongside annotations and sample metadata
Language: HTML - Size: 126 MB - Last synced at: about 4 hours ago - Pushed at: almost 4 years ago - Stars: 58 - Forks: 7
UPHL-BioNGS/Cecret
Reference-based consensus creation
Language: Nextflow - Size: 281 MB - Last synced at: 6 days ago - Pushed at: 6 days ago - Stars: 57 - Forks: 28
nf-core/circrna
circRNA quantification, differential expression analysis and miRNA target prediction of RNA-Seq data
Language: Nextflow - Size: 90.4 MB - Last synced at: 3 months ago - Pushed at: 3 months ago - Stars: 57 - Forks: 32
nf-core/rnasplice
rnasplice is a bioinformatics pipeline for RNA-seq alternative splicing analysis
Language: Nextflow - Size: 160 MB - Last synced at: 2 months ago - Pushed at: 6 months ago - Stars: 57 - Forks: 36
mribeirodantas/NextflowSnippets
This repository hosts a large collection of Nextflow snippets
Size: 88.9 KB - Last synced at: 8 months ago - Pushed at: 10 months ago - Stars: 57 - Forks: 1
nf-core/rnavar
gatk4 RNA variant calling pipeline
Language: Nextflow - Size: 4.45 MB - Last synced at: 14 days ago - Pushed at: 14 days ago - Stars: 55 - Forks: 41
IARCbioinfo/IARC-nf
List of IARC bioinformatics pipelines and resources
Size: 706 KB - Last synced at: 23 days ago - Pushed at: 23 days ago - Stars: 53 - Forks: 10
nf-core/crisprseq
A pipeline for the analysis of CRISPR edited data. It allows the evaluation of the quality of gene editing experiments using targeted next generation sequencing (NGS) data (`targeted`) as well as the discovery of important genes from knock-out or activation CRISPR-Cas9 screens using CRISPR pooled DNA (`screening`).
Language: Nextflow - Size: 22.8 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 53 - Forks: 33
nf-core/demultiplex
Demultiplexing pipeline for sequencing data
Language: Nextflow - Size: 13.8 MB - Last synced at: 26 days ago - Pushed at: 26 days ago - Stars: 51 - Forks: 47
SciLifeLab/NGI-RNAseq Fork of nf-core/rnaseq 📦
Nextflow RNA-Seq Best Practice analysis pipeline, used at the SciLifeLab National Genomics Infrastructure.
Language: Groovy - Size: 45.4 MB - Last synced at: over 1 year ago - Pushed at: about 7 years ago - Stars: 51 - Forks: 42
nf-core/scnanoseq
Single-cell/nuclei pipeline for data derived from Oxford Nanopore and 10X Genomics
Language: Nextflow - Size: 41.4 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 50 - Forks: 16
nf-core/isoseq
Genome annotation with PacBio Iso-Seq. Takes raw subreads as input, generate Full Length Non Chemiric (FLNC) sequences and produce a bed annotation.
Language: Nextflow - Size: 6.47 MB - Last synced at: 17 days ago - Pushed at: 17 days ago - Stars: 48 - Forks: 21
nextflow-io/nf-validation Fork of nextflow-io/nf-schema 📦
Params validation plugin for Nextflow pipelines
Language: Groovy - Size: 2.77 MB - Last synced at: 1 day ago - Pushed at: over 1 year ago - Stars: 48 - Forks: 18
nf-core/epitopeprediction
A bioinformatics best-practice analysis pipeline for epitope prediction and annotation
Language: Nextflow - Size: 5.08 MB - Last synced at: 15 days ago - Pushed at: 15 days ago - Stars: 47 - Forks: 29
openproblems-bio/openproblems-v2
Formalizing and benchmarking open problems in single-cell genomics
Language: Python - Size: 160 MB - Last synced at: over 1 year ago - Pushed at: over 1 year ago - Stars: 46 - Forks: 16
IARCbioinfo/needlestack
Multi-sample somatic variant caller
Language: R - Size: 49.8 MB - Last synced at: about 2 years ago - Pushed at: almost 4 years ago - Stars: 46 - Forks: 14
seqeralabs/wave
On-demand containers provisioning service
Language: Groovy - Size: 32.8 MB - Last synced at: about 14 hours ago - Pushed at: about 16 hours ago - Stars: 45 - Forks: 8
nextflow-io/nf-schema
Functionality for working with pipeline and sample sheet schema files in Nextflow pipelines
Language: Groovy - Size: 8.23 MB - Last synced at: 26 days ago - Pushed at: 26 days ago - Stars: 45 - Forks: 28
NBISweden/pipelines-nextflow
A set of workflows written in Nextflow for Genome Annotation.
Language: Nextflow - Size: 338 KB - Last synced at: 3 months ago - Pushed at: over 1 year ago - Stars: 45 - Forks: 18
montilab/pipeliner
A flexible Nextflow-based framework for the definition of sequencing data processing pipelines
Language: Nextflow - Size: 23.2 MB - Last synced at: 7 months ago - Pushed at: about 6 years ago - Stars: 44 - Forks: 13
bentsherman/nf-boost
Experimental features for Nextflow
Language: Groovy - Size: 204 KB - Last synced at: 3 months ago - Pushed at: 3 months ago - Stars: 43 - Forks: 2
nf-core/pathogensurveillance
Surveillance of pathogens using population genomics and sequencing
Language: Nextflow - Size: 283 MB - Last synced at: 2 months ago - Pushed at: 4 months ago - Stars: 43 - Forks: 7
Gregor-Mendel-Institute/aradeepopsis
A versatile, fully open-source pipeline to extract phenotypic measurements from plant images
Language: Nextflow - Size: 2.75 MB - Last synced at: 2 months ago - Pushed at: 6 months ago - Stars: 43 - Forks: 8
gencorefacility/variant-calling-pipeline-gatk4
Variant Calling Pipeline Using GATK4 and Nextflow
Language: Nextflow - Size: 23.4 KB - Last synced at: over 2 years ago - Pushed at: almost 3 years ago - Stars: 40 - Forks: 40
nf-core/deepvariant Fork of lifebit-ai/DeepVariant 📦
Please consider using/contributing to https://github.com/nf-core/sarek
Language: Nextflow - Size: 7.18 MB - Last synced at: almost 2 years ago - Pushed at: over 4 years ago - Stars: 40 - Forks: 18
nf-core/mhcquant
Identify and quantify MHC eluted peptides from mass spectrometry raw data
Language: Nextflow - Size: 26.2 MB - Last synced at: 15 days ago - Pushed at: 15 days ago - Stars: 39 - Forks: 31
nf-core/multiplesequencealign
A pipeline to run and systematically evaluate Multiple Sequence Alignment (MSA) methods.
Language: Nextflow - Size: 19.6 MB - Last synced at: about 1 month ago - Pushed at: about 1 month ago - Stars: 38 - Forks: 14
ewels/nf-core-rnaseq Fork of nf-core/rnaseq
See the main fork of this repository here >>>
Language: Nextflow - Size: 71.5 MB - Last synced at: 9 months ago - Pushed at: 9 months ago - Stars: 38 - Forks: 4
guigolab/grape-nf
An automated RNA-seq pipeline using Nextflow
Language: Nextflow - Size: 7.74 MB - Last synced at: 3 months ago - Pushed at: about 1 year ago - Stars: 37 - Forks: 10
Midnighter/nextflow-gotchas
A collection of unexpected challenges and learnings with nextflow and nf-core.
Language: Shell - Size: 707 KB - Last synced at: 6 months ago - Pushed at: about 2 years ago - Stars: 37 - Forks: 9
nf-core/variantbenchmarking
Pipeline to evaluate and validate the accuracy of variant calling methods in genomic research
Language: Nextflow - Size: 22.4 MB - Last synced at: 1 day ago - Pushed at: 1 day ago - Stars: 36 - Forks: 19
nextflow-io/vscode-language-nextflow
Nextflow language support for Visual Studio Editor
Language: TypeScript - Size: 10.9 MB - Last synced at: about 19 hours ago - Pushed at: about 21 hours ago - Stars: 35 - Forks: 18
montilab/nf-gwas-pipeline
A Nextflow Genome-Wide Association Study (GWAS) Pipeline
Language: R - Size: 5.25 MB - Last synced at: 9 days ago - Pushed at: 5 months ago - Stars: 35 - Forks: 22
nf-core/proteomicslfq
Proteomics label-free quantification (LFQ) analysis pipeline
Language: Nextflow - Size: 3.59 MB - Last synced at: 2 months ago - Pushed at: 10 months ago - Stars: 35 - Forks: 21