In view of the poor recommendation performance of traditional resource collaborative filtering recommendation algorithms, this article proposes a collaborative filtering recommendation model based on ...deep learning for art and MOOC resources. This model first uses embedding vectors based on the context of metapaths for learning. Embedding vectors based on the context of metapaths aggregate different metapath information and different MOOCs may have different preferences for different metapaths. Secondly, to capture this preference drift, the model introduces an attention mechanism, which can improve the interpretability of the recommendation results. Then, by introducing the Laplacian matrix into the prior distribution of the hidden factor feature matrix, the relational network information is effectively integrated into the model. Finally, compared with the traditional model using the scoring matrix, the model in this article using text word vectors effectively alleviates the impact of data sparsity and greatly improves the accuracy of prediction. After analyzing the experimental results, compared with other algorithms, the resource collaborative filtering recommendation model proposed in this article has achieved better recommendation results, with good stability and scalability.
The recent emergence of a novel coronavirus (SARS-CoV-2) in China has caused significant public health concerns. Recently, ACE2 was reported as an entry receptor for SARS-CoV-2. In this study, we ...present the crystal structure of the C-terminal domain of SARS-CoV-2 (SARS-CoV-2-CTD) spike (S) protein in complex with human ACE2 (hACE2), which reveals a hACE2-binding mode similar overall to that observed for SARS-CoV. However, atomic details at the binding interface demonstrate that key residue substitutions in SARS-CoV-2-CTD slightly strengthen the interaction and lead to higher affinity for receptor binding than SARS-RBD. Additionally, a panel of murine monoclonal antibodies (mAbs) and polyclonal antibodies (pAbs) against SARS-CoV-S1/receptor-binding domain (RBD) were unable to interact with the SARS-CoV-2 S protein, indicating notable differences in antigenicity between SARS-CoV and SARS-CoV-2. These findings shed light on the viral pathogenesis and provide important structural information regarding development of therapeutic countermeasures against the emerging virus.
Display omitted
•SARS-CoV-2 interacts with hACE2 via S protein CTD•A 2.5-Å structure of SARS-CoV-2-CTD in complex with hACE2 is resolved•The SARS-CoV-2-CTD displays stronger affinity for hACE2 compared with SARS-RBD•SARS-CoV-2 -CTD is antigenically different from SARS-RBD
The crystal structure of the C-terminal domain of the SARS-CoV-2 spike protein in complex with human ACE2 reveals insights into the mechanisms of binding of this virus and its differences from SARS.
•The prevalence of posttraumatic stress symptoms (PTSS) in China hardest-hit areas a month after the COVID-19 outbreak was 7%.•Hierarchical regression analysis and non-parametric test suggested that ...women reported significant higher PTSS in the domains of re-experiencing, negative alterations in cognition or mood, and hyper-arousal.•Participants with better sleep quality or less frequency of early awakenings reported lower PTSS.
The outbreak of COVID-19 in China in December 2019 has been identified as a pandemic and a health emergency of global concern. Our objective was to investigate the prevalence and predictors of posttraumatic stress symptoms (PTSS) in China hardest-hit areas during COVID-19 outbreak, especially exploring the gender difference existing in PTSS. One month after the December 2019 COVID-19 outbreak in Wuhan China, we surveyed PTSS and sleep qualities among 285 residents in Wuhan and surrounding cities using the PTSD Checklist for DSM-5 (PCL-5) and 4 items from the Pittsburgh Sleep Quality Index (PSQI). Hierarchical regression analysis and non-parametric test were used to analyze the data. Results indicated that the prevalence of PTSS in China hardest-hit areas a month after the COVID-19 outbreak was 7%. Women reported significant higher PTSS in the domains of re-experiencing, negative alterations in cognition or mood, and hyper-arousal. Participants with better sleep quality or less frequency of early awakenings reported lower PTSS. Professional and effective mental health services should be designed in order to aid the psychological wellbeing of the population in affected areas, especially those living in hardest-hit areas, females and people with poor sleep quality.
Computer simulations are an important implementation to experimental methods working on polymer nanocomposites (PNCs), which have advanced properties because of their unique hierarchy ...microstructures. In this paper, different computer simulation methods applied to investigate the structures and properties of PNCs and the simulation predicted physical properties of PNCs are reviewed. The fundamentals of applying molecular dynamics simulation method to calculate different physical properties of PNCs are explained accompanied with detailed examples. The results can help to understand the progress on PNC field using simulation methods especially different-sized molecular dynamics simulation methods.
Display omitted
•Diverse kinds of computer simulation methods were reviewed and compared.•Simulation results of multiple physical properties were explored.•The fundamentals of calculating different physical properties using simulation methods were explained.
Sepsis-related acute lung injury (ALI) remains a major cause of mortality in critically ill patients and lacks specific therapy. Mitochondrial dysfunction is involved in the progression of septic ...lung injury. Mitochondrial dynamics, mitophagy, and biogenesis converge to constitute the assiduous quality control of mitochondria (MQC). Heme oxygenase-1 (HO-1) protects against sepsis-induced ALI through the modulation of mitochondrial dynamics. However, the causal relationship between HO-1 and the general processes of MQC, and their associated cellular pathways in sepsis-related ALI remain ill-defined. Herein, lipopolysaccharide (LPS)-induced ALI in Sprague-Dawley rats together with LPS-induced oxidative injury in RAW264.7 macrophages were used to investigate whether the PI3K/Akt pathway-mediated induction of HO-1 preserves MQC and alleviates septic lung injury. After pretreatment with hemin, a potent inducer of HO-1, LPS-induced cell apoptosis, enhanced mitochondrial fragmentation, and mitochondrial membrane potential damage were significantly reduced in macrophages. In rats, these effects were accompanied by a higher survival rate, less damage to lung tissue, a 28.5% elevation in lung mitochondria MnSOD activity, and a 39.2% increase in respiratory control ratios. Concomitantly, HO-1 induction preserved the dynamic process of mitochondrial fusion/fission (Mfn2, OPA1, Drp1), promoted mitochondrial biogenesis (NRF1, PGC1α, Tfam), and facilitated the key mediators of mitochondrial mitophagy (Parkin, PINK1) at mRNA and protein levels. Notably, LY294002, a PI3K inhibitor, or knockdown of PI3K by small interfering RNA significantly suppressed Akt phosphorylation, attenuated HO-1 induction, and further reversed these beneficial effects evoked by hemin pretreatment in RAW264.7 cells or rats received LPS, indicating a direct involvement of PI3K/Akt pathway. Taken together, our results indicated that HO-1 activation, through PI3K/Akt pathway, plays a critical role in protecting lung from oxidative injury in the setting of sepsis by regulating MQC. HO-1 may therefore be a therapeutic target for the prevention sepsis-related lung injury.
Alzheimer's disease (AD) is the most common reason for elderly dementia in the world. We proposed that memory loss in AD is related to destabilization of mushroom postsynaptic spines involved in ...long-term memory storage. We demonstrated previously that stromal interaction molecule 2 (STIM2)-regulated neuronal store-operated calcium entry (nSOC) in postsynaptic spines play a key role in stability of mushroom spines by maintaining activity of synaptic Ca(2+)/calmodulin kinase II (CaMKII). Furthermore, we demonstrated previously that the STIM2-nSOC-CaMKII pathway is downregulated in presenilin 1 M146V knock-in (PS1-M146V KI) mouse model of AD, leading to loss of hippocampal mushroom spines in this model. In the present study, we demonstrate that hippocampal mushroom postsynaptic spines are also lost in amyloid precursor protein knock-in (APPKI) mouse model of AD. We demonstrated that loss of mushroom spines occurs as a result of accumulation of extracellular β-amyloid 42 in APPKI culture media. Our results indicate that extracellular Aβ42 acts by overactivating mGluR5 receptor in APPKI neurons, leading to elevated Ca(2+) levels in endoplasmic reticulum, compensatory downregulation of STIM2 expression, impaired synaptic nSOC, and reduced CaMKII activity. Pharmacological inhibition of mGluR5 or overexpression of STIM2 rescued synaptic nSOC and prevented mushroom spine loss in APPKI hippocampal neurons. Our results indicate that downregulation of synaptic STIM2-nSOC-CaMKII pathway causes loss of mushroom synaptic spines in both presenilin and APPKI mouse models of AD. We propose that modulators/activators of this pathway may have a potential therapeutic value for treatment of memory loss in AD. Significance statement: A direct connection between amyloid-induced synaptic mushroom spine loss and neuronal store-operated calcium entry pathway is shown. These results provide strong support for the calcium hypothesis of neurodegeneration and further validate the synaptic store-operated calcium entry pathway as a potential therapeutic target for Alzheimer's disease.
•The prevalence of PTSD among the Chinese public one month after the COVID-19 outbreak was 4.6%.•Female, having recent epidemic area contact history, population at high risk of infection, and poor ...sleep quality were identified as risk factors for PTSD.•With regard to psychological intervention during the COVID-19 outbreak, females, people with poor sleep quality, and those who are at high risk of infection, such as people residing in high disease-prevalent regions and having had close contact with patients deserve special attention.
To examine the prevalence of and risk factors for acute posttraumatic stress disorder (PTSD) shortly after the massive outbreak of COVID-19 in China.
An online anonymous survey was conducted between 30 January and 3 February, 2020. The survey included two self-administered questionnaires: one collected personal information (gender, age, education background), current location, recent epidemic area contact history, the classification of population, and subjective sleep quality; the other was the PTSD Checklist for DSM-5 (PCL-5).
A total of 2091 Chinese participated in the current study. The prevalence of PTSD among the Chinese public one month after the COVID-19 outbreak was 4.6%. Multiple linear regression analysis revealed that gender (p < 0.001), epidemic area contact history (p = 0.047), classification of population (p < 0.001), and subjective sleep quality (p < 0.001) could be regarded as predictors for PTSD.
First, the majority of participants in this study were the general public, with confirmed or suspected patients being a small part. Second, the measurement of PTSD in this study might be vulnerable to selection bias because of an online self-report study, such as participants’ recruitment. Third, the prevalence of PTSD in this study was estimated by an online questionnaire rather than a clinical interview.
The results suggested that some Chinese showed acute PTSD during the COVID-19 outbreak. Therefore, comprehensive psychological intervention needs further implementation. Furthermore, females, people who had recent epidemic area contact history, those at high risk of infection or with poor sleep quality deserve special attention.
In this work, we reported a novel and effective cancer treatment strategy by fabricating carbon dot (CD)-polyethylenimine (PEI)-doxorubicin (DOX) antitumor drug complexes from a combination of ...PEI-passivated CDs (CD-PEI) and DOX. CD-PEI was synthesized by the one-step microwave hydrothermal carbonization of a mixture of glycerol and PEI-25k, enabling simultaneous synthesis and surface passivation of CDs. DOX was loaded onto CD-PEI by electrostatic interactions. The results show that this system not only improves selective drug release but also prolongs the drug release time and improves the killing effect on tumors. Compared with free DOX, the CD-PEI-DOX complex has a stronger killing effect on liver cancer cells (MHCC-97L and Hep3B cells) but a very low killing effect on normal liver cells (L02). Studies have also confirmed that compared with DOX alone, CD-PEI-DOX nanoparticles can effectively inhibit tumors because of the larger amount of drugs localized in tumor cells and the higher apoptosis rate of MHCC-97L cells. In vivo experiments confirmed that CD-PEI-DOX has a stronger inhibitory effect on tumor growth, indicating that CD-PEI-DOX nanomedicine has inhibitory effects on tumors.
The bonding surface structure generated by the repair of concrete structures has been paid more attention as a weak point. The effects of old concrete age, interface roughness, and freeze-thawing ...(F-T) attack on adhesive interface are comprehensively investigated. In this study, six kinds of interface roughness and five different old concrete age are designed. The interfacial bonding property is mainly evaluated by splitting tensile strength (
). Fractal analysis was used to characterize the interface roughness using laser scanning data. In general, the
increased with the increasing value of interface fractal dimension. The relationship between
and fractal dimension value was further analyzed, considering the old concrete ages and the F-T cycles. The results show that the effect of roughness on the bonding property of new-to-old concrete is more significant than the age of old concrete, and the influence of the F-T cycles on the bonding surface is mainly reflected in the initial stage of the F-T deterioration process. The relative dynamic elasticity modulus decreased obviously under F-T cycles, especially for the specimens with low interface roughness. In combination with the results of two non-destructive methods (ultrasonic non-destructive test and relative dynamic elastic modulus test), the larger roughness and the smaller age of old concrete can improve the bond performance.
Highlights
In terms of components and structures, this review summarizes progresses and highlights strategies of MOF derivatives for efficient electromagnetic wave absorption.
We also systematically ...delineate relevant theories and points out the prospects and current challenges.
To tackle the aggravating electromagnetic wave (EMW) pollution issues, high-efficiency EMW absorption materials are urgently explored. Metal–organic framework (MOF) derivatives have been intensively investigated for EMW absorption due to the distinctive components and structures, which is expected to satisfy diverse application requirements. The extensive developments on MOF derivatives demonstrate its significantly important role in this research area. Particularly, MOF derivatives deliver huge performance superiorities in light weight, broad bandwidth, and robust loss capacity, which are attributed to the outstanding impedance matching, multiple attenuation mechanisms, and destructive interference effect. Herein, we summarized the relevant theories and evaluation methods, and categorized the state-of-the-art research progresses on MOF derivatives in EMW absorption field. In spite of lots of challenges to face, MOF derivatives have illuminated infinite potentials for further development as EMW absorption materials.
PDF
