3,202 research outputs found
Lipid storage changes in human skeletal muscle during detraining
Exercise training is known to increase intramuscular triglyceride content in both trained and untrained legs. The purpose of the study was to determine the changes of intramyocellular lipids (IMCL) and extramyocellular lipids (EMCL) of both trained and untrained legs during detraining. We measured both IMCL and EMCL levels in previously trained vs. untrained legs during 4-weeks of detraining after 6-weeks of strength training. Eight young men (aged 21.4 + / - 1.4 years) trained their vastus lateralis muscle in one leg using a dynamometer, whereas the contralateral leg served as untrained control. Muscle cross-sectional area (CSA), IMCL, EMCL, total creatine (creatine + phophocreatine) of extensor (vastus lateralis) muscles were assessed using magnetic resonance imaging (MRI) and proton magnetic resonance spectra (H-1-MRS) before training, 3 days after and 28 days after the last bout of training. CSA was increased in both legs by Day 3 after training, and was still high at Day 28 post-training; IMCL increased in both legs by Day 3 after training, then decreased at Day 28 post-training only in the untrained leg; EMCL shows no significant change by Day 3 after training, but at Day 28 post-training has increased in the trained leg and decreased in the untrained leg; total creatine did not change significantly. Conclusion: Decreases of IMCL and EMCL storages in previously untrained leg during detraining indicates an ectopic influence on tissue lipid storage by different metabolic demand among tissues in the same human body
Bis(2-aminopyridine-κN 1)bis(benzoato-κO)cobalt(II)
In the title compound, [Co(C7H5O2)2(C5H6N2)2], the CoII atom is hexacoordinated by four O atoms from two benzoate anions, and two N atoms from two 2-aminopyridine molecules, resulting in a distorted octahedral geometry. Both benzoate anions act as bidentate ligands and both 2-aminopyridine molecules are coordinated to the metal through their pyridyl N atoms. The crystal packing is stabilized by intermolecular N—H⋯O hydrogen bonds, C—H⋯π, and π–π stacking interactions involving benzoate anions and 2-aminopyridine molecules
ALECE: An Attention-based Learned Cardinality Estimator for SPJ Queries on Dynamic Workloads (Extended)
For efficient query processing, DBMS query optimizers have for decades relied
on delicate cardinality estimation methods. In this work, we propose an
Attention-based LEarned Cardinality Estimator (ALECE for short) for SPJ
queries. The core idea is to discover the implicit relationships between
queries and underlying dynamic data using attention mechanisms in ALECE's two
modules that are built on top of carefully designed featurizations for data and
queries. In particular, from all attributes in the database, the data-encoder
module obtains organic and learnable aggregations which implicitly represent
correlations among the attributes, whereas the query-analyzer module builds a
bridge between the query featurizations and the data aggregations to predict
the query's cardinality. We experimentally evaluate ALECE on multiple dynamic
workloads. The results show that ALECE enables PostgreSQL's optimizer to
achieve nearly optimal performance, clearly outperforming its built-in
cardinality estimator and other alternatives.Comment: VLDB 202
DILI: A Distribution-Driven Learned Index
Targeting in-memory one-dimensional search keys, we propose a novel
DIstribution-driven Learned Index tree (DILI), where a concise and
computation-efficient linear regression model is used for each node. An
internal node's key range is equally divided by its child nodes such that a key
search enjoys perfect model prediction accuracy to find the relevant leaf node.
A leaf node uses machine learning models to generate searchable data layout and
thus accurately predicts the data record position for a key. To construct DILI,
we first build a bottom-up tree with linear regression models according to
global and local key distributions. Using the bottom-up tree, we build DILI in
a top-down manner, individualizing the fanouts for internal nodes according to
local distributions. DILI strikes a good balance between the number of leaf
nodes and the height of the tree, two critical factors of key search time.
Moreover, we design flexible algorithms for DILI to efficiently insert and
delete keys and automatically adjust the tree structure when necessary.
Extensive experimental results show that DILI outperforms the state-of-the-art
alternatives on different kinds of workloads.Comment: PVLDB Volume 1
3-(4-Chlorophenyl)-2-(diisopropylamino)-1-benzofuro[3,2-d]pyrimidin-4(3H)-one
In the molecule of the title compound, C22H22ClN3O2, the three fused rings of the benzofuro[3,2-d]pyrimidine system are almost coplanar. This ring system is oriented with respect to the substituted benzene ring at a dihedral angle of 79.05 (3)°. Intramolecular C—H⋯N hydrogen bonding results in the formation of a six-membered ring. In the crystal structure, π–π stacking interactions involving the furan, pyrimidinone and benzene rings are present [centroid-to-centroid distances in the range 3.258 (1)–3.870 (1) Å]
Poly[[aqua(μ2-oxalato)(μ2-2-oxidopyridinium-3-carboxylato)holmium(III)] monohydrate]
In the title complex, {[Ho(C2O4)(C6H4NO3)(H2O)]·(H2O)}n, the HoIII ion is coordinated by three O atoms from two 2-oxidopyridinium-3-carboxylate ligands, four O atoms from two oxalate ligands and one water molecule in a distorted bicapped trigonal-prismatic geometry. The 2-oxidopyridinium-3-carboxylate and oxalate ligands link the HoIII ions into a layer in (100). These layers are further connected by intermolecular O—H⋯O hydrogen bonds involving the coordinated water molecules to assemble a three-dimensional supramolecular network. The uncoordinated water molecule is involved in N—H⋯O and O—H⋯O hydrogen bonds within the layer
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