{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2021:S2UZ2TKCF2NUQUUNVJK7Z5UBXH","short_pith_number":"pith:S2UZ2TKC","canonical_record":{"source":{"id":"2108.01497","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.chem-ph","submitted_at":"2021-08-03T13:37:02Z","cross_cats_sorted":[],"title_canon_sha256":"15fd2486970bb99915c82754781b101a97d34a5e2aad10a4dd0c34e7ac34d019","abstract_canon_sha256":"e02a9010e167ac298700861ccecaf13e6a956e6785970a10082baa59576dc742"},"schema_version":"1.0"},"canonical_sha256":"96a99d4d422e9b48528daa55fcf681b9f9a222db83d8538117abffca799db7d1","source":{"kind":"arxiv","id":"2108.01497","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2108.01497","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"arxiv_version","alias_value":"2108.01497v1","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2108.01497","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_12","alias_value":"S2UZ2TKCF2NU","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_16","alias_value":"S2UZ2TKCF2NUQUUN","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_8","alias_value":"S2UZ2TKC","created_at":"2026-07-05T03:03:03Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2021:S2UZ2TKCF2NUQUUNVJK7Z5UBXH","target":"record","payload":{"canonical_record":{"source":{"id":"2108.01497","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.chem-ph","submitted_at":"2021-08-03T13:37:02Z","cross_cats_sorted":[],"title_canon_sha256":"15fd2486970bb99915c82754781b101a97d34a5e2aad10a4dd0c34e7ac34d019","abstract_canon_sha256":"e02a9010e167ac298700861ccecaf13e6a956e6785970a10082baa59576dc742"},"schema_version":"1.0"},"canonical_sha256":"96a99d4d422e9b48528daa55fcf681b9f9a222db83d8538117abffca799db7d1","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T03:03:03.558274Z","signature_b64":"gapK4f0XHuyQ8e/hgzLHhwM8lR8rkeTLdJwWvMGJcIDbIYSXfhPYTI9nZJmIF5Kqmcp527KtvUQ7iF9HM8xvBg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"96a99d4d422e9b48528daa55fcf681b9f9a222db83d8538117abffca799db7d1","last_reissued_at":"2026-07-05T03:03:03.557833Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T03:03:03.557833Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2108.01497","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T03:03:03Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"mfTC70i3XwSWNT4GIZrX1jJ6/Fwyh24p9o5E6vV7TbuFCXVrpB68+CXVm1d5UR3Oo0JP4ICehbxlaglLvWl6DA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-03T16:28:03.876389Z"},"content_sha256":"192d414fd409dfa3b56f5b3d08444d70c0a430ce7088bd1403926c7b559930cb","schema_version":"1.0","event_id":"sha256:192d414fd409dfa3b56f5b3d08444d70c0a430ce7088bd1403926c7b559930cb"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2021:S2UZ2TKCF2NUQUUNVJK7Z5UBXH","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Effect of the hydrogenation solvent in the PHIP-SAH hyperpolarization of [1- 13 C]pyruvate","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":[],"primary_cat":"physics.chem-ph","authors_text":"Carla Carrera, Eleonora Cavallari, Francesca Reineri, Oksana Bondar, Silvio Aime","submitted_at":"2021-08-03T13:37:02Z","abstract_excerpt":"ParaHydrogen Induced Polarization-Side Arm Hydrogenation (PHIP-SAH) is an inexpensive tool to obtain hyperpolarized pyruvate (and other metabolites) that can be applied to in-vivo diagnostics, for the investigation of metabolic processes. This method is based on hydrogenation, using hydrogen enriched in the para-isomer, of unsaturated substrates, catalyzed, usually, by a homogeneous rhodium(I) complex. In this work, the effect of the solvent on the hydrogenation efficiency and on the hyperpolarization level were investigated. Coordinating solvents, such as acetone and methanol, can increase si"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2108.01497","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2108.01497/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T03:03:03Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"wqPMRXZPH0Byq8KnjCqIuOwWE/1a+2So6tCrodEDRSGNjaRQjd3kNmYmxNJcHeORW1cHNf66b9sQ++RkmjnmAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-03T16:28:03.876896Z"},"content_sha256":"d9556fad26f3829174fda0939d1e07748a063f90387b724b7dac0051d8738786","schema_version":"1.0","event_id":"sha256:d9556fad26f3829174fda0939d1e07748a063f90387b724b7dac0051d8738786"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/bundle.json","state_url":"https://pith.science/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-03T16:28:03Z","links":{"resolver":"https://pith.science/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH","bundle":"https://pith.science/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/bundle.json","state":"https://pith.science/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/state.json","well_known_bundle":"https://pith.science/.well-known/pith/S2UZ2TKCF2NUQUUNVJK7Z5UBXH/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:S2UZ2TKCF2NUQUUNVJK7Z5UBXH","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"e02a9010e167ac298700861ccecaf13e6a956e6785970a10082baa59576dc742","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.chem-ph","submitted_at":"2021-08-03T13:37:02Z","title_canon_sha256":"15fd2486970bb99915c82754781b101a97d34a5e2aad10a4dd0c34e7ac34d019"},"schema_version":"1.0","source":{"id":"2108.01497","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2108.01497","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"arxiv_version","alias_value":"2108.01497v1","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2108.01497","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_12","alias_value":"S2UZ2TKCF2NU","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_16","alias_value":"S2UZ2TKCF2NUQUUN","created_at":"2026-07-05T03:03:03Z"},{"alias_kind":"pith_short_8","alias_value":"S2UZ2TKC","created_at":"2026-07-05T03:03:03Z"}],"graph_snapshots":[{"event_id":"sha256:d9556fad26f3829174fda0939d1e07748a063f90387b724b7dac0051d8738786","target":"graph","created_at":"2026-07-05T03:03:03Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2108.01497/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"ParaHydrogen Induced Polarization-Side Arm Hydrogenation (PHIP-SAH) is an inexpensive tool to obtain hyperpolarized pyruvate (and other metabolites) that can be applied to in-vivo diagnostics, for the investigation of metabolic processes. This method is based on hydrogenation, using hydrogen enriched in the para-isomer, of unsaturated substrates, catalyzed, usually, by a homogeneous rhodium(I) complex. In this work, the effect of the solvent on the hydrogenation efficiency and on the hyperpolarization level were investigated. Coordinating solvents, such as acetone and methanol, can increase si","authors_text":"Carla Carrera, Eleonora Cavallari, Francesca Reineri, Oksana Bondar, Silvio Aime","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.chem-ph","submitted_at":"2021-08-03T13:37:02Z","title":"Effect of the hydrogenation solvent in the PHIP-SAH hyperpolarization of [1- 13 C]pyruvate"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2108.01497","kind":"arxiv","version":1},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:192d414fd409dfa3b56f5b3d08444d70c0a430ce7088bd1403926c7b559930cb","target":"record","created_at":"2026-07-05T03:03:03Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"e02a9010e167ac298700861ccecaf13e6a956e6785970a10082baa59576dc742","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"physics.chem-ph","submitted_at":"2021-08-03T13:37:02Z","title_canon_sha256":"15fd2486970bb99915c82754781b101a97d34a5e2aad10a4dd0c34e7ac34d019"},"schema_version":"1.0","source":{"id":"2108.01497","kind":"arxiv","version":1}},"canonical_sha256":"96a99d4d422e9b48528daa55fcf681b9f9a222db83d8538117abffca799db7d1","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"96a99d4d422e9b48528daa55fcf681b9f9a222db83d8538117abffca799db7d1","first_computed_at":"2026-07-05T03:03:03.557833Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:03:03.557833Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"gapK4f0XHuyQ8e/hgzLHhwM8lR8rkeTLdJwWvMGJcIDbIYSXfhPYTI9nZJmIF5Kqmcp527KtvUQ7iF9HM8xvBg==","signature_status":"signed_v1","signed_at":"2026-07-05T03:03:03.558274Z","signed_message":"canonical_sha256_bytes"},"source_id":"2108.01497","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:192d414fd409dfa3b56f5b3d08444d70c0a430ce7088bd1403926c7b559930cb","sha256:d9556fad26f3829174fda0939d1e07748a063f90387b724b7dac0051d8738786"],"state_sha256":"bc1cbb18dbd40e025d3103de40cdec6da6b209e63316d2d437178864d778bcda"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"rIQqSgIA/jDK2Qx1cSjzpdxlT80KtCw0oGfGDCX1sdn53VLmmgg+N/FCUWj8ZggpD1/ndpgXSnZjdW1/kWvfCw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-03T16:28:03.880242Z","bundle_sha256":"bd6b67d73e6cc92be2d2cf4305459455db76a0e4d9e8453c38d8e0a4b991c88b"}}