L dwarfs detection from SDSS images using improved Faster R-CNN

We present a data-driven approach to automatically detect L dwarfs from Sloan Digital Sky Survey(SDSS) images using an improved Faster R-CNN framework based on deep learning. The established L dwarf automatic detection (LDAD) model distinguishes L dwarfs from other celestial objects and backgrounds in SDSS field images by learning the features of 387 SDSS images containing L dwarfs. Applying the LDAD model to the SDSS images containing 93 labeled L dwarfs in the test set, we successfully detected 83 known L dwarfs with a recall rate of 89.25% for known L dwarfs. Several techniques are implemented in the LDAD model to improve its detection performance for L dwarfs,including the deep residual network and the feature pyramid network. As a result, the LDAD model outperforms the model of the original Faster R-CNN, whose recall rate of known L dwarfs is 80.65% for the same test set. The LDAD model was applied to detect L dwarfs from a larger validation set including 843 labeled L dwarfs, resulting in a recall rate of 94.42% for known L dwarfs. The newly identified candidates include L dwarfs, late M and T dwarfs, which were estimated from color (i-z) and spectral type relation. The contamination rates for the test candidates and validation candidates are 8.60% and 9.27%, respectively. The detection results indicate that our model is effective to search for L dwarfs from astronomical images.Comment: 12 pages, 10 figures, accepted to be published in A

catena-Poly[[dichloridocopper(II)]-μ-4,4′-bis­(benzimidazol-1-yl)biphen­yl]

In the title compound, [CuCl2(C26H18N4)]n, the Cu(II) ion is four-coordinated by two N atoms from two 4,4′-bis­(benzo­imidazol-1-yl)biphenyl ligands and two chloride anions, in a slightly distorted tetra­hedral environment. The biphenyl ligand acts as a linear bidentate ligand, connecting the metal atoms into an infinite chain parallel to [101]. In the biphenyl ligand, the two benzene rings make a dihedral angle of 33.19 (7)°

STEM: Unleashing the Power of Embeddings for Multi-task Recommendation

Multi-task learning (MTL) has gained significant popularity in recommender systems as it enables simultaneous optimization of multiple objectives. A key challenge in MTL is negative transfer, but existing studies explored negative transfer on all samples, overlooking the inherent complexities within them. We split the samples according to the relative amount of positive feedback among tasks. Surprisingly, negative transfer still occurs in existing MTL methods on samples that receive comparable feedback across tasks. Existing work commonly employs a shared-embedding paradigm, limiting the ability of modeling diverse user preferences on different tasks. In this paper, we introduce a novel Shared and Task-specific EMbeddings (STEM) paradigm that aims to incorporate both shared and task-specific embeddings to effectively capture task-specific user preferences. Under this paradigm, we propose a simple model STEM-Net, which is equipped with an All Forward Task-specific Backward gating network to facilitate the learning of task-specific embeddings and direct knowledge transfer across tasks. Remarkably, STEM-Net demonstrates exceptional performance on comparable samples, achieving positive transfer. Comprehensive evaluation on three public MTL recommendation datasets demonstrates that STEM-Net outperforms state-of-the-art models by a substantial margin. Our code is released at https://github.com/LiangcaiSu/STEM

Thermal analysis of FeCoCu pre-alloyed powders used for diamond tools

By simulating the pressureless sintering process, the thermal effects of FeCoCu pre-alloyed powders have been investigated. According to the notions of the Kissinger method, the activation energies in the expansion-shrinkage conversion stage are analyzed. Results show that with Fe content increasing, the specimens’ specific heat capacity values present the increasing trend. The 25 %Fe–15 %Co–60 %Cu specimens have negative enthalpy value at 10 and 20°C/min heating rate but positive values at 30 °С/min. For the specimens with lower Cu content, the enthalpies are always positive. It is established that both the specific heat capacity and enthalpy are larger when at higher heating rates. The activation energy of the 65 %Fe–15 %Co–20 %Cu specimens is 10 times higher than that of the 25 %Fe–15 %Co–60 %Cu specimens and the 45 %Fe–15 %Co–40 %Cu specimens.При моделюванні процесу спікання без тиску досліджено термічні ефекти в попередньо легованих порошках FeCoCu. З використанням методу Кіссінджера проаналізовано енергію активації на стадії розширення–усадка. Результати показують, що при збільшенні вмісту Fe значення питомої теплоємності демонструють тенденцію до зростання. Зразки 25 %Fe–15 %Co–60 %Cu мають негативні значення ентальпії при швидкості нагріву 10 ° і 20 °С/хв, але позитивні при 30 °С/хв. Для зразків з меншим вмістом Cu ентальпія завжди позитивна. Встановлено, що питома теплоємність і ентальпія більші при більш високіх швидкостях нагрівання. Енергія активації зразків 65 %Fe–15 %Co–20 %Cu у 10 разів вища, ніж зразків 25 %Fe–15 %Co–60 %Cu і 45 %Fe–15 %Co–40 %Cu.При моделировании процесса спекания без приложения давления исследованы термические эффекты в предварительно легированных порошках FeCoCu. С использованием метода Киссинджера проанализирована энергия активации на стадии расширение–усадка. Результаты показывают, что с увеличением содержания железа значения удельной теплоемкости образцов демонстрируют тенденцию к повышению. Образцы 25 %Fe–15 %Co–60 %Cu имеют отрицательные значения энтальпии при скорости нагрева 10 и 20 °С/мин, но положительные при 30 °С/мин. Для образцов с меньшим содержанием Cu энтальпия всегда положительна. Установлено, что удельная теплоемкость и энтальпия больше при более высоких скоростях нагрева. Энергия активации образцов 65 %Fe–15 %Co–20 %Cu в 10 раз выше, чем образцов 25 %Fe–15 %Co–60 %Cu и 45 %Fe–15 %Co–40 %Cu

PTEN and rapamycin inhibiting the growth of K562 cells through regulating mTOR signaling pathway

<p>Abstract</p> <p>Objective</p> <p>To investigate, <it>in vitro</it>, the regulatory effects of tumor-suppressing gene PTEN on mTOR (mammalian target of rapamycin) signaling pathway, the effects of transfected PTEN and rapamycin on the growth inhibition, and apoptosis induction for human leukemia cell line K562 cells.</p> <p>Methods</p> <p>K562 cells were transfected with recombined adenovirus-PTEN vector containing green fluorescent protein (Ad-PTEN-GFP), followed by the treatment of the cells with or without rapamycin. The proliferation inhibition rate and apoptotic rate of these transfected and/or rapamycin treated K562 cells were measured by MTT assay and flow cytometry (FCM), the expression levels of PTEN-, mTOR-, cyclinD1- and P27^kip1- mRNA were measured by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR), the protein expression levels of PTEN, Akt, p-Akt were detected by western blotting.</p> <p>Results</p> <p>The proliferation of K562 cells was inhibited by PTEN gene transfection with/without the treatment of rapamycin. The expression levels of PTEN- and P27^kip1- mRNA were up-regulated, and the mTOR- and cyclinD1- mRNA were down-regulated in K562 cells after the cells transfected with wild type PTEN gene and treated with rapamycin.</p> <p>Conclusion</p> <p>PTEN and rapamycin inhibited mTOR expression by acting as an upstream regulator of mTOR. Low dose rapamycin in combination with over-expressed PTEN might have synergistic effects on inhibiting the proliferation and promoting apoptosis of K562 cells.</p

Exposures to Particulate Matter and Polycyclic Aromatic Hydrocarbons and Oxidative Stress in Schoolchildren

BACKGROUND: Air pollution is known to contribute to respiratory and cardiovascular mortality, and morbidity. Oxidative stress has been suggested as one of the main mechanisms for these effects on health. OBJECTIVE: The aim of this study was to analyze the effects of exposure to particulate matter (PM) with aerodynamic diameters &lt;= 10 mu m (PM(10)) and &lt;= 2.5 mu M (PM(2.5)) and polycyclic aromatic hydrocarbons (PAHs) on urinary malondialdehyde (MDA) levels in schoolchildren. METHODS: The study population consisted of 120 schoolchildren. The survey and measurements were conducted in four cities two in China (Ala Shan and Beijing) and two in Korea (Jeju and Seoul) between 4 and 9 June 2007. We measured daily ambient levels of PM and their metal components at the selected schools during the study period. We also measured urinary 1-hydroxypyrene (1-OHP) and 2-naphthol, to assess PAH exposure, and MDA, to assess oxidative stress. Measurements were conducted once a day for 5 consecutive days. We constructed a linear mixed model after adjusting for individual variables to estimate the effects of PM and PAH on oxidative stress. RESULTS: We found statistically significant increases in urinary MDA levels with ambient PM concentrations from the current day to the 2 previous days (p &lt; 0.0001). Urinary 1-OHP level also showed a positive association with urinary MDA level, which was statistically significant with or without PM in the model (p &lt; 0.05). Outdoor PM and urinary 1-OHP were synergistically associated with urinary MDA levels. Some metals bound to PM(10) (aluminum, iron, strontium, magnesium, silicon, arsenic, barium, zinc, copper, and cadmium) and PM(2.5) (magnesium, iron, strontium, arsenic, cadmium, zinc, aluminum, mercury, barium, and copper) also had significant associations with urinary MDA level. CONCLUSION: Exposure to PM air pollution and PAHs was associated with oxidative stress in schoolchildren.Environmental SciencesPublic, Environmental &amp; Occupational HealthToxicologySCI(E)40ARTICLE4579-58311

Screening and Stability Evaluation of Angiotensin Converting Enzyme Inhibitory Peptides from Bangia fusco-purpurea

In this study, peptide fractions (F1-F4) with different molecular masses were obtained from Bangia fusco-purpurea through enzymatic hydrolysis and ultrafiltration. F2, with molecular masses of 800–2 000 Da, exhibited the highest in vitro angiotensin-converting enzyme (ACE) inhibitory activity as determined by high performance liquid chromatography (HPLC). The amino acid sequence of F2 was identified through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and de novo sequencing using PEAKS Studio software. Six ACE inhibitory peptides that stably bind to ACE were selected through molecular docking. The predicted peptides were synthesized by solid-phase synthesis and their in vitro ACE inhibitory activity was verified. Among them, L1 (LVLLFLFGE) showed the highest ACE inhibitory activity with a half maximal inhibitory concentration (IC50) value of 14.22 μg/mL. Molecular docking results indicated that the inhibition of ACE by L1 was mainly attributed to its ability to form hydrogen bond interactions with the active site of ACE. Finally, the effects of temperature, pH, metal ions, light exposure, and simulated gastrointestinal digestion on the stability of L1 were investigated. The results revealed that L1 was highly stable to heat and ionic strength. However, its activity gradually decreased at pH > 2, and was affected by ultraviolet treatment. The ACE inhibitory activity of L1 decreased after simulated gastric and intestinal digestion, but was still significant