In the huge number of online university education resources, it is difficult for learners to quickly locate the resources they need, which leads to “information trek.” Traditional information ...recommendation methods tend to ignore the characteristics of learners, who are the main subjects of education. In order to improve the recommendation accuracy, a recommendation algorithm based on improved collaborative filtering model is proposed in this paper. Firstly, according to the student behavior data, consider the behavior order to create the behavior graph and behavior route. Then, the path of text type is vectorized by the Keras Tokenizer method. Finally, the similarity between multidimensional behavior path vectors is calculated, and path collaborative filtering recommendations are performed for each dimension separately. The MOOC data of a university in China are introduced to experimentally compare the algorithm of the article as well as the control group algorithm. The results show that the proposed algorithm takes better values in evaluation indexes, thus verifying that this algorithm can improve the effectiveness of innovation and entrepreneurship education resources recommendation in universities.
The
D
(
∗
)
Ξ
cc
(
∗
)
system and
Ξ
¯
cc
(
∗
)
Ξ
cc
(
∗
)
system can be related to the
D
(
∗
)
D
¯
(
∗
)
system via heavy anti-quark di-quark symmetry (HADS). In this work, we employ a contact-range ...effective field theory to systematically investigate the likely existence of molecules in these systems in terms of the hypothesis that X(3872) is a
1
+
+
D
D
¯
∗
bound state in the isospin symmetry limit, with some of the unknown low energy constants estimated using the light-meson saturation approximation. In the meson–meson system, a
J
PC
=
2
+
+
D
¯
∗
D
∗
molecule commonly referred to as
X
(4013) is reproduced, which is the heavy quark spin partner of
X
(3872). In the meson-baryon system, we predict two triply charmed pentaquark molecules,
J
P
=
1
/
2
-
D
∗
Ξ
cc
and
J
P
=
5
/
2
-
D
∗
Ξ
cc
∗
. In the baryon-baryon system, there exist seven di-baryon molecules,
J
PC
=
0
-
+
Ξ
¯
cc
Ξ
cc
,
J
PC
=
1
-
-
Ξ
¯
cc
Ξ
cc
,
J
PC
=
1
-
+
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
1
-
-
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
2
-
+
Ξ
¯
cc
Ξ
cc
∗
,
J
PC
=
2
-
+
Ξ
¯
cc
∗
Ξ
cc
∗
, and
J
PC
=
3
-
-
Ξ
¯
cc
∗
Ξ
cc
∗
. Among them, the
J
PC
=
0
-
+
Ξ
¯
cc
Ξ
cc
molecule may contribute to the
X
(7200) state recently observed by the LHCb Collaboration, which implies that
X
(7200) can be related to
X
(3872) via HADS. As a byproduct, with the heavy quark flavor symmetry we also study likely existence of molecular states in the
B
(
∗
)
B
¯
(
∗
)
,
B
¯
(
∗
)
Ξ
bb
(
∗
)
, and
Ξ
¯
bb
(
∗
)
Ξ
bb
(
∗
)
systems.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A high-efficiency concurrent dual-band GaN power amplifier (PA) is designed and fabricated based on the network parameter extraction (NPE) method, where the expanded optimum load impedance spaces of ...continuous modes are applied to construct the NPE criteria to facilitate harmonic tuning. A swallow-spit process is proposed to improve the effectiveness of NPE by dynamically changing the criteria. The prototype design process verified that the proposed algorithm is easy to be implemented, which avoids the cumbersome tunings and complex numerical derivations on the parameters of the dual-band output matching networks. Measurement results demonstrate that the fabricated GaN PA achieves saturated output powers of 40.5 dBm ± 0.4 dBm and 41 dBm ± 0.3 dBm over dual bands of 0.6-0.8 GHz and 1.6-1.9 GHz with peak PAEs of 71%-74% and 68%-73%, respectively.
A recent analysis by the LHCb Collaboration suggests the existence of three narrow pentaquarklike states-the P_{c}(4312), P_{c}(4440), and P_{c}(4457)-instead of just one in the previous analysis the ...P_{c}(4450). The closeness of the P_{c}(4312) to the Dover ¯Σ_{c} threshold and the P_{c}(4440) and P_{c}(4457) to the Dover ¯^{*}Σ_{c} threshold suggests a molecular interpretation of these resonances. We show that these three pentaquarklike resonances can be naturally accommodated in a contact-range effective field theory description that incorporates heavy-quark spin symmetry. This description leads to the prediction of all the seven possible S-wave heavy antimeson-baryon molecules that is, there should be four additional molecular pentaquarks in addition to the P_{c}(4312), P_{c}(4440), and P_{c}(4457), providing the first example of a heavy-quark spin symmetry molecular multiplet that is complete. If this is confirmed, it will not only give us an impressive example of the application of heavy-quark symmetries and effective field theories in hadron physics, it will also uncover a clear and powerful ordering principle for the molecular spectrum, reminiscent of the SU(3)-flavor multiplets to which the light hadron spectrum conforms.
Inspired by the recent discovery of a doubly charmed tetraquark state Tcc+ by the LHCb Collaboration, we employ the effective Lagrangian approach to investigate the decay width of Tcc+→D+D0π0/D0D0π+ ...and Tcc+→D0D+γ with the assumption that Tcc+ is an isoscalar DD⁎ molecule. We show that both the Tcc→DDπ and Tcc→DDγ modes contribute to the decay width of Tcc, with the former being dominant. The resulting total decay width of about Γ=63 keV is smaller than the experimental decay width obtained from the Breit-Wigner fit of the LHCb data, Γ=410±165±43−38+18 keV, while close to the number obtained from the alternative unitary analysis, Γ=48±2−14+0 keV, which supports the molecular nature of Tcc.
Although gemcitabine-based chemotherapy has been established as a core multimodal therapy for non-small cell lung cancer (NSCLC) treatment, its clinical efficacy remains limited by the development of ...acquired resistance following tumor metastasis and relapse. In this study, we investigated how gemcitabine-resistant (GR) cells contribute to the development of NSCLC tumor malignancy via exosome-mediated transfer of microRNAs.
We first studied the mechanism of exosome internalization via PKH-67 staining and an immunofluorescence assay, then confirmed our finding by transmission electron microscopy and western blot analysis. Candidate miRNAs were identified through microarray analysis. Thereafter, RT-PCR, MTS, Transwell and soft agar assays were performed to assess the role of exosomic miR-222-3p in vitro. A 3' untranslated region reporter assay was applied to identify the target of miR-222-3p. A lung metastasis mouse model was constructed to evaluate tumor growth and metastasis in vivo. Finally, clinical samples were used for correlation analysis between exosomic miR-222-3p levels and patients' response to gemcitabine.
A549-GR-derived exosomes were internalized by receipt cells via caveolin- and lipid raft-dependent endocytosis, which allowed the transfer of miR-222-3p. Exosomic miR-222-3p enhanced the proliferation, gemcitabine resistance, migration, invasion, and anti-anoikis of parental sensitive cells by directly targeting the promoter of SOCS3. In addition, a higher level of exosomic miR-222-3p in sera usually predicted worse prognosis in NSCLC patients.
Our data demonstrate that exosomic-miR-222-3p functions as a principal regulator of gemcitabine resistance and malignant characteristics by targeting SOCS3. The exosomic miR-222-3p level in sera may be a potential prognostic biomarker for predicting gemcitabine sensitivity in NSCLC patients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The chain sequence of a poly(styrene‐co‐methyl acrylate) copolymer is designed to form a V‐shaped gradient sequence via controlled/living radical emulsion copolymerization. This specially designed ...chain sequence gives this common copolymer the capacity of multishape memory. The copolymer can sequentially recover to its permanent shape from three or more previously programmed temporary shapes with the stimulus of temperature.
More and more online learning apps are emerging, thanks to the development of Internet plus education and online learning platforms. Learning efficacy is the leading impactor of online learning ...participation. To avoid inefficiency and poor effect of online learning, it is necessary to explore the theory on the relationship between self-efficacy improvement and online learning participation. This paper examines the influence of self-efficacy improvement on online learning participation. Firstly, a general normal distribution map was drawn for self-efficacy. Then, a prediction model was established for participation based on the series of online learning behaviors. In addition, the k-means clustering (KMC) algorithm was optimized by information entropy, and the flow of the improved KMC was explained. The proposed model was proved valid through experiments.
Salt stress can significantly affect plant growth and agricultural productivity. Receptor-like kinases (RLKs) are believed to play essential roles in plant growth, development, and responses to ...abiotic stresses. Here, we identify a receptor-like cytoplasmic kinase, salt tolerance receptor-like cytoplasmic kinase 1 (STRK1), from rice (Oryza sativa) that positively regulates salt and oxidative stress tolerance. Our results show that STRK1 anchors and interacts with CatC at the plasma membrane via palmitoylation. CatC is phosphorylated mainly at Tyr-210 and is activated by STRK1. The phosphorylation mimic form CatCY210D exhibits higher catalase activity both in vitro and in planta, and salt stress enhances STRK1-mediated tyrosine phosphorylation on CatC. Compared with wild-type plants, STRK1-overexpressing plants exhibited higher catalase activity and lower accumulation of H2O2 as well as higher tolerance to salt and oxidative stress. Our findings demonstrate that STRK1 improves salt and oxidative tolerance by phosphorylating and activating CatC and thereby regulating H2O2 homeostasis. Moreover, overexpression of STRK1 in rice not only improved growth at the seedling stage but also markedly limited the grain yield loss under salt stress conditions. Together, these results offer an opportunity to improve rice grain yield under salt stress.
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