With the rapid expansion of online education, there is a burgeoning interest within the EdTech space to offer tailored learning experiences that cater to individual student's abilities and needs. ...Within this framework, knowledge tracing tasks have garnered considerable attention. The primary objective of knowledge tracing is to develop a model that assesses a student's proficiency in a particular skill based on their historical performance in exercises, enabling predictions regarding the likelihood of correct responses in future exercises. While existing knowledge tracing models often incorporate information such as students' exercise answering history and skill mastery level, they frequently overlook the students' mental states during the learning process.
This paper addresses this gap by introducing a novel psychological factors-enhanced heterogeneous learning interactive graph knowledge tracing model (Psy-KT). This model delineates the interactions among students, exercises, and skills through a heterogeneous graph, supplementing it with four psychological factors that capture students' mental states during the learning process: frustration level, confusion level, concentration level, and boredom level. In the modeling of students' learning processes, we incorporate the forgetting curve and construct relevant cognitive parameters from the features. Additionally, we employ the Item Response Theory (IRT) model to predict students' performance in answering exercises at the subsequent time step. This model not only delves into the psychological aspects of students during the learning process but also integrates the simulation of forgetting, a natural phenomenon in the learning journey. The inclusion of cognitive parameters enhances the description of changes in students' abilities throughout the learning process. This dual focus allows for a more comprehensive understanding of students' learning behaviors while providing a high level of interpretability for the model.
Empirical validation of the Psy-KT model is conducted using four publicly available datasets, demonstrating its superior performance in predicting students' future performance. Through rigorous experimentation, the integration of psychological and forgetting factors in the Psy-KT model not only improves predictive accuracy but also enables educators to offer more targeted tutoring and advice, enhancing the overall efficacy of the learning experience.
High performance mixed potential type NO2 sensors using porous yttria-stabilized zirconia (YSZ) layers doped with different concentration graphite as solid electrolyte and LaFeO3 as sensing electrode ...were fabricated and characterized. LaFeO3 was prepared by a typical citrate sol–gel method and characterized using XRD. The surface morphology and porosity of porous YSZ layers were characterized by field emission scanning electron microscope (FESEM). The sensor doped with 3 wt% graphite shows the highest response (−76.4 mV to 80 ppm NO2) and the response is linearly dependent on the logarithm of NO2 concentration in the range of 10–200 ppm. The sensor measurement results also present good repeatability and cross-sensitivity.
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Shikonin (SHK) has been proven to have a good anti-tumor effect. However, poor water solubility and low bioavailability limit its wide application in clinical practice. In this study, to overcome ...these drawbacks, RGD-modified shikonin-loaded liposomes (RGD-SSLs-SHK) were successfully prepared. It exhibited excellent physicochemical characteristics including particle size, zeta potential, encapsulation efficiency, and delayed release time. Meanwhile, the targeting activity of the RGD-modified liposomes was demonstrated by flow cytometry and confocal microscopy in the α
β₃-positive MDA-MB-231 cells. Besides exhibiting greater cytotoxicity in vitro, compared with non-targeted shikonin-loaded liposomes (SSLs-SHK), RGD-SSLs-SHK could also evidently induce apoptosis by decreasing the expression of Bcl-2 and increasing the expression of Bax. It could also inhibit cell proliferation, migration, invasion, and adhesion by reducing the expression of MMP-9 and the level of NF-κB p65, but did not affect the expression of MMP-2 in the MDA-MB-231 cells. Therefore, these findings indicated that the strategy to use RGD-modified liposomes as carriers for targeted delivery of shikonin is a very promising approach to achieve breast cancer targeted therapy.
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This paper studies the fully distributed formation control problem of multi-robot systems without global position measurements subject to unknown longitudinal slippage constraints. It is difficult ...for robots to obtain accurate and stable global position information in many cases, such as when indoors, tunnels and any other environments where GPS (global positioning system) is denied, thus it is meaningful to overcome the dependence on global position information. Additionally, unknown slippage, which is hard to avoid for wheeled robots due to the existence of ice, sand, or muddy roads, can not only affect the control performance of wheeled robot, but also limits the application scene of wheeled mobile robots. To solve both problems, a fully distributed finite time state observer which does not require any global position information is proposed, such that each follower robot can estimate the leader's states within finite time. The distributed adaptive controllers are further designed for each follower robot such that the desired formation can be achieved while overcoming the effect of unknown slippage. Finally, the effectiveness of the proposed observer and control laws are verified by simulation results.
This paper proposes a series of optimized scalable contact-capacitive radio frequency micro- electro-mechanical systems (RF MEMS) switches for millimeter wave applications. Due to the ...contact-capacitive topology, the ON-state and OFF-state of the switch can be designed separately to obtain smaller <inline-formula> <tex-math notation="LaTeX">C_{ON} </tex-math></inline-formula> and larger <inline-formula> <tex-math notation="LaTeX">C_{OFF} </tex-math></inline-formula>, which results in high capacitance ratio (<inline-formula> <tex-math notation="LaTeX">C_{r} </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">C_{ON} </tex-math></inline-formula> is defined by capacitance of the contacts, and it is optimized for low insertion loss (<inline-formula> <tex-math notation="LaTeX">IL_{ON} </tex-math></inline-formula>). The <inline-formula> <tex-math notation="LaTeX">C_{OFF} </tex-math></inline-formula> is defined by the metal-insulator-metal (MIM) capacitor, and it is designed for working band and scalable performance. The measurements of the fabricated devices show acceptable agreements with design and simulation. The optimized switches perform well with <inline-formula> <tex-math notation="LaTeX">IL_{ON} </tex-math></inline-formula> better than 1.5dB and capacitive ratio about 124. The switches follow scaling rules from 20GHz to 110GHz. Linearity (IIP3) of the switches are tested to be higher than 60dBm, and calculated to be higher than 80dBm. Performances of the switch can be further improved and optimized in the future study.
High-temperature processes, such as packaging and annealing, are challenges for Radio-Frequency Micro-Electro-Mechanical-Systems (RF MEMS) structures, which could lead to device failure. Coefficient ...of thermal expansion (CTE) mismatch and the material's creep effect affect the fabrication and performance of the MEMS, especially experiencing the high temperature. In this paper, the Thermal-Mechanical-Stress-Creep (TMSC) effect during thermal processes from room temperature (RT) to 200 °C is modeled and measured, in which an Au-cantilever-based RF MEMS switch is selected as a typical device example. A novel Isolation-Test Method (ITM) is used to measure precise TMSC variation. This method can achieve resolutions of sub-nanometer (0.5 nm) and attofarad (1 aF). There are three stages in the thermal processes, including temperature ramping up, temperature dwelling, and temperature ramping down. In different stages, the thermal-mechanical stress in anchor and cantilever, the grain growth of gold, and the thermal creep compete with each other, which result in the falling down and curling up of the cantilever. These influencing factors are decoupled and discussed in different stages. The focused ion beam (FIB) is used to characterize the change of the gold grain. This study shows the possibility of predicting the deformation of MEMS structures during different high-temperature processes. This model can be extended for material selection and package temperature design of MEMS cantilever in the further studies.
Patients are typically diagnosed with both hypertension and fibrosarcoma. Medical oncologists must prescribe suitable anti-hypertensive medications while considering anti-tumor drugs. Recently, ...immunotherapy has become prominent in cancer treatment. Nonetheless, it is unknown what role anti-hypertensive medications will play in immunotherapy.
We examined the effects of six first-line anti-hypertensive medications on programmed cell death protein 1 antibody (PD1ab) in tumor treatment using a mouse model of subcutaneous fibrosarcoma. The drugs examined were verapamil, losartan, furosemide, spironolactone, captopril, and hydrochlorothiazide (HCTZ). The infiltration of CD8
T cells was examined by immunohistochemistry. Additionally, several in vitro and in vivo assays were used to study the effects of HCTZ on human fibrosarcoma cancer cells to explore its mechanism.
Verapamil suppressed tumor growth and showed an improved effect on the tumor inhibition of PD1ab. Captopril did not affect tumor growth but brought an unexpected benefit to PD1ab treatment. In contrast, spironolactone and furosemide showed no effect on tumor growth but had an offset effect on the PD1ab therapy. Consequently, the survival time of mice was also significantly reduced. Notably, losartan and HCTZ, especially HCTZ, promoted tumor growth and weakened the effect of PD1ab treatment. Consistent results were observed in vivo and in vitro using the human fibrosarcoma cell line HT1080. We determined that the Solute Carrier Family 12 Member 3 (SLC12A3), a known target of HCTZ, may be the principal factor underlying its effect-enhancing properties through mechanism studies employing The Cancer Genome Atlas (TCGA) data and in vivo and in vitro assays.
Verapamil and captopril potentiated the anti-tumor effect of PD1ab, whereas spironolactone and furosemide weakened the effect of PD1ab on tumor inhibition. Alarmingly, losartan and HCTZ promoted tumor growth and impaired the effect of PD1ab. Furthermore, we preliminarily found that HCTZ may promote tumor progression through SLC12A3. Based on this study, futher mechanism researches and clinical trials should be conducted in the future.
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The model uncertainties and the heterogeneous energy states burden the effective aggregation of electric vehicles (EVs), especially coupling with the real-time frequency dynamic of the electrical ...grid. Integrating the advantages of deep learning and reinforcement learning, deep reinforcement learning shows its potential to relieve this challenge, where an intelligent agent fully considers the individual state of charge (SOC) difference of EV and the grid state to optimize the aggregation performance. However, existing policies of deep reinforcement learning usually provide deterministic and certain actions, and it is difficult to deal with the increasing uncertainties and randomness in modern electrical systems. In this paper, a probability-based management strategy is proposed with continuous action space based on the deep reinforcement learning, which provides fine-grained energy management and addresses the time-varying dynamics from EVs and electrical grid simultaneously. Moreover, an optimization based on the proximal policy is further introduced to clip the policy upgradation speed to enhance the training stability. The effectiveness of proposed energy management structure and policy optimization strategy are verified on various scenarios and uncertainties, which demonstrates advantageous performance in the SOC management and frequency maintenance. Besides the performance merits, the training procedure is also presented revealing the evolution reason for the proposed approach.
This paper demonstrates a method to reduce the decay time in AlGaN/GaN photodetectors by a pulsed heating mode. A suspended AlGaN/GaN heterostructure photodetector integrated with a micro-heater is ...fabricated and characterized under ultraviolet illumination. We have observed that the course of persistent photoconductivity was effectively accelerated by applying pulsed heating. The decay time is significantly reduced from 175 s by DC heating to 116 s by 50 Hz pulsed heating at the same power (280 mW). With the same pulse duty cycle and a 50 Hz pulsed heating frequency, a reduction of 30%-45% in decay time is measured compared to DC heating.
Billions of doses of coronavirus disease 2019 (COVID-19) vaccines have been administered and several cases of thrombocytopenia with thrombosis syndrome (TTS) have been reported after the ...administration of adenoviral vector vaccines. However, the effects of an inactivated COVID-19 vaccine, CoronaVac, on coagulation are not well understood.
In this randomized, controlled, open-label phase IV clinical trial, 270 participants including 135 adults aged 18-59 years and 135 adults aged 60 years or older, were enrolled and randomized to the CoronaVac group or to the control group in a 2:1 ratio and received two doses of CoronaVac or one dose of the 23-valent pneumococcal polysaccharide vaccine and one dose of inactivated hepatitis A vaccine on days 0 and 28, respectively. Adverse events were collected for 28 days after each dose. Blood samples were taken on days 0, 4, 14, 28, 32, 42, and 56 after the first dose to evaluate neutralizing antibody titers and laboratory parameters of coagulation function and blood glucose.
Fourteen days after the second dose of CoronaVac, the seroconversion rates of neutralizing antibodies against the prototype strain and beta, gamma, and delta variants of concern (VOC) of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) reached peak values of 89.31%, 23.3%, 45.3%, and 53.5%, respectively. The incidence of adverse reactions was 43.6% and 52.2% in the CoronaVac group and in the control group, respectively. All were mild or moderate in severity. For the laboratory parameters, there was no difference in the means of any parameter between the two groups at any time point, except for the D-dimer on day 14. However, the D-dimer in the CoronaVac group decreased on day 14 compared to the value at baseline, while a higher D-dimer value, instead of a decreased D-dimer value, was a risk factor for TTS.
CoronaVac showed a good safety profile and could induce a humoral response against the prototype and VOCs of SARS-CoV-2 in adults 18 years or older, with no abnormal effects on laboratory parameters of blood glucose and coagulation function.
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