COOOL: A Learning-To-Rank Approach for SQL Hint Recommendations

Query optimization is a pivotal part of every database management system (DBMS) since it determines the efficiency of query execution. Numerous works have introduced Machine Learning (ML) techniques to cost modeling, cardinality estimation, and end-to-end learned optimizer, but few of them are proven practical due to long training time, lack of interpretability, and integration cost. A recent study provides a practical method to optimize queries by recommending per-query hints but it suffers from two inherited problems. First, it follows the regression framework to predict the absolute latency of each query plan, which is very challenging because the latencies of query plans for a certain query may span multiple orders of magnitude. Second, it requires training a model for each dataset, which restricts the application of the trained models in practice. In this paper, we propose COOOL to predict Cost Orders of query plans to cOOperate with DBMS by Learning-To-Rank. Instead of estimating absolute costs, COOOL uses ranking-based approaches to compute relative ranking scores of the costs of query plans. We show that COOOL is theoretically valid to distinguish query plans with different latencies. We implement COOOL on PostgreSQL, and extensive experiments on join-order-benchmark and TPC-H data demonstrate that COOOL outperforms PostgreSQL and state-of-the-art methods on single-dataset tasks as well as a unified model for multiple-dataset tasks. Our experiments also shed some light on why COOOL outperforms regression approaches from the representation learning perspective, which may guide future research

Electrical Detection of the Mechanical Alteration of Sickling Red Blood Cells within a Microfluidic Capillary Network

International audienceIn this paper we demonstrate the capability to detect red blood cells mechanical disorders, in particular the sickle cell disease, using the electrical signature of the cell transit within a microfluidic restriction mimicking the blood capillaries

Chemical ordering suppresses large-scale electronic phase separation in doped manganites

For strongly correlated oxides, it has been a long-standing issue regarding the role of the chemical ordering of the dopants on the physical properties. Here, using unit cell by unit cell superlattice growth technique, we determine the role of chemical ordering of the Pr dopant in a colossal magnetoresistant (La1-yPry)1-xCaxMnO3 (LPCMO) system, which has been well known for its large length-scale electronic phase separation phenomena. Our experimental results show that the chemical ordering of Pr leads to marked reduction of the length scale of electronic phase separations. Moreover, compared with the conventional Pr-disordered LPCMO system, the Pr-ordered LPCMO system has a metal–insulator transition that is ~100 K higher because the ferromagnetic metallic phase is more dominant at all temperatures below the Curie temperature

Investigation of cracks in GaN films grown by combined hydride and metal organic vapor-phase epitaxial method

Cracks appeared in GaN epitaxial layers which were grown by a novel method combining metal organic vapor-phase epitaxy (MOCVD) and hydride vapor-phase epitaxy (HVPE) in one chamber. The origin of cracks in a 22-μm thick GaN film was fully investigated by high-resolution X-ray diffraction (XRD), micro-Raman spectra, and scanning electron microscopy (SEM). Many cracks under the surface were first observed by SEM after etching for 10 min. By investigating the cross section of the sample with high-resolution micro-Raman spectra, the distribution of the stress along the depth was determined. From the interface of the film/substrate to the top surface of the film, several turnings were found. A large compressive stress existed at the interface. The stress went down as the detecting area was moved up from the interface to the overlayer, and it was maintained at a large value for a long depth area. Then it went down again, and it finally increased near the top surface. The cross-section of the film was observed after cleaving and etching for 2 min. It was found that the crystal quality of the healed part was nearly the same as the uncracked region. This indicated that cracking occurred in the growth, when the tensile stress accumulated and reached the critical value. Moreover, the cracks would heal because of high lateral growth rate

Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172

Study of red blood cell deformability using impedance measurement within a microfluidic device : sickle cell disease analysis

En raison d’une mutation génétique, l'hémoglobine contenue dans les globules rouges (GRs) se polymérise sous conditions de désoxydation, conduisant à une modification des propriétés en déformabilité des GRs. Ce travail de thèse propose une investigation par des mesures électriques de cinétique de passage comme nouveau moyen pour une caractérisation plus rapide et plus poussée de la déformabilité des GRs. Il s’appuie sur une puce microfluidique réutilisable contenant un réseau de capillaires mimétique de la circulation sanguine au sein des organes et intégrant des électrodes de mesure électrique. La discrimination entre des globules rouges normaux, des globules rouges chauffés, des globules rouges sphérocytaires et des globules rouges drépanocytaires constitue le cœur de cette thèse.Pour la mise en œuvre de ce projet, une analyse analytique utilisant un modèle numérique a été utilisée pour estimer le comportement fluidique et électrique de la puce microfluidique. La microfabrication a été utilisée pour obtenir la puce microfluidique. Le packaging utilise un PDMS recouvert de parylène permettant un assemblage réversible et simplifiant la mise en œuvre du système.Plus de 2000 globules rouges ont été analysés pour la comparaison entre des globules rouges normaux ou pathologiques (drépanocytaires ou atteints par la sphérocytose héréditaire). Une discrimination entre les globules rouges normaux et anormaux a été observée en comparant ces paramètres. Une corrélation entre les caractérisationsélectriques mesurées et les propriétés mécaniques des globules rouges est ainsi obtenue.Due to the genetic disorder, the hemoglobin in red blood cell (RBC) polymerizes under deoxidation conditions, leading to the variation of RBC deformability. Statistical analyses of the variation of RBC deformability are usually performed with an optical microscope, by observing RBC shape and behaviour under flow rate. However, this method lacks productiveness. This thesis studies an electrical investigation of flow kinetics across the mimetic capillary. It offers a new original way for faster and further characterization of the alteration of red blood cell (RBC) deformability. It is based on a reusable microfluidic chip which contains a mimicking capillaries network with embedded electrodes. Discrimination between normal RBCs, heated RBCs, hereditary spherocytosis RBCs and sickle cells has been achieved.During this project, an analytical approach and a finite element analysis were used to estimate the fluidic and electric behaviour of the cell flowing in the microfluidic device. Specific microfabrication was required to obtain the reusable microfluidic PDMS chip and electrodes. The packaging uses a parylene-coated PDMS allowing a reversible assembly and simplifying the implementation of the system.More than 2000 red blood cells were analysed for comparison between normal and pathological red blood cells (sickle cell disease or hereditary spherocytosis). The results mainly exploit the transit time and the amplitude of the current blockage when RBCs transit within the capillary. Discrimination between normal and abnormal RBCs was observed with these data. A correlation between the measured electrical characterizations and the mechanical properties of the red blood cells is thus obtained

MicroRNA-125a Regulates Cell Proliferation Via Directly Targeting E2F2 in Osteosarcoma

Background/Aims: Increasing evidence has shown that miR-125a plays important role in human cancer progression. However, little is known about the function of miR-125a in osteosarcoma. Methods: The expression of miR-125a in osteosarcoma tissues and cell lines were examined by qRT-PCR. The biological role of miR-125a in osteosarcoma cell proliferation was examined in vitro. The targets of miR-125a were identified by a dual-luciferase reporter assay. Results: The results showed that the expression of miR-125a expression is significantly lower in osteosarcoma tissues and cell lines. Survival curves showed that the survival of patients in high miR-125a expression was significantly longer than that of patients with low miR-125a expression, and multivariate analysis suggested that miR-125a is an independent prognostic factor for osteosarcoma patients. In addition, it was found in this study that miR-125a can inhibit the growth of osteosarcoma cells. The dual-luciferase reporter assay demonstrated that E2F2 is a novel target gene for miR-125a. In addition, in a recovery experiment, it was shown that miR-125a inhibits the biological function of osteosarcoma cells by inhibiting the expression of E2F2. Conclusion: Our results suggest that miR-125a acts as a tumor suppressor via regulation of E2F2 expression in osteosarcoma progression, and miR-125a may represent a novel therapeutic target for the treatment of osteosarcoma

Monitoring Biological Cell Flow within a Mimicking Capillary Device with Impedance Measurement

International audienceThis paper presents a microfluidic system, characterizing the red blood cell (RBC) deformability through its transit time in a microchannel, which dimensions reproducing blood microcirculation capillary. Electrodes are integrated within the microchannel for electrical measurements. The transit time is measured with the electrical blockade produced when the RBC squeezes in the microchannel (d = 5 μm diameter, while the cell diameter is 8 μm). In order todetermine most suitable electrical frequency range for the voltage applied to excitation electrodes, FEM numerical simulation of the bioimpedance is achieved and presented in this paper. We investigated the frequency response of the bioimpedance taking into account the electrode polarization, the dielectric properties of the medium, a single shell model for RBC and finally the RBC position within the microchannel