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In this paper, we combine the critical point theory and variational method to investigate the following a class of coupled fractional systems of Choquard type $ \begin{equation*} \left\{ \begin{array}{l} (-\Delta)^{s}u+\lambda_{1}u& = (I_{\alpha}*|u|^{p})|u|^{p-2}u+\beta v \quad &&\text{in}\\ \mathbb{R}^{N}, \ (-\Delta)^{s}v+\lambda_{2}v& = (I_{\alpha}*|v|^{p})|v|^{p-2}v+\beta u \quad &&\text{in}\ \mathbb{R}^{N}, \end{array} \right. \end{equation*} $ with $ s\in(0, 1), \ N\geq 3, \ \alpha\in(0, N), \ p > 1 $, $ \lambda_{i} > 0 $ are constants for $ i = 1, \ 2 $, $ \beta > 0 $ is a parameter, and $ I_{\alpha}(x) $ is the Riesz Potential. We prove the existence and asymptotic behaviour of positive ground state solutions of the systems by using constrained minimization method and Hardy-Littlewood-Sobolev inequality. Moreover, nonexistence of nontrivial solutions is also obtained.

The aim of this paper is to study the existence of ground states for a class of fractional Kirchhoff type equations with critical or supercritical nonlinearity $ (a+b\int_{\mathbb{R}^{3}}|(-\bigtriangleup)^{\frac{s}{2}}u|^{2}dx)(-\bigtriangleup)^{s}u = \lambda u +|u|^{q-2 }u+\mu|u|^{p-2}u, \ x\in\mathbb{R}^{3}, $ with prescribed $ L^{2} $-norm mass $ \int_{\mathbb{R}^{3}}u^{2}dx = c^{2} $ where $ s\in(\frac{3}{4}, \ 1), \ a, b, c > 0, \ \frac{6+8s}{3} < q < 2_{s}^{\ast}, \ p\geq 2^{\ast}_{s}\ (2^{\ast}_{s} = \frac{6}{3-2s}), \ \mu > 0 $ and $ \lambda\in \mathbb{R} $ as a Langrange multiplier. By combining an appropriate truncation argument with Moser iteration method, we prove that the existence of normalized solutions for the above equation when the parameter $ \mu $ is sufficiently small.

We investigate a class of fractional linearly coupled Choquard systems. For the subcritical case and all critical cases, we prove the existence, nonexistence and symmetry of positive ground state solutions of systems, by using the Nehari manifold method, the Pohožaev identity and the Schwartz symmetrization rearrangements. In particular, we overcome the lack of compactness of the critical nonlinearities by using the behaviour of sufficiently small Nehari energy levels.

In this paper, we investigate the existence of the least energy sign-changing solutions for nonlinear elliptic equations driven by nonlocal integro-differential operators with critical nonlinearity. By using constrained minimization method and topological degree theory, we obtain a least energy sign-changing solution for them under much weaker conditions. As a particular case, we drive an existence theorem of sign-changing solutions for the fractional Laplacian equations with critical growth.

We study a singular Schrödinger-Kirchhoff-Poisson system by the variational methods and the Nehari manifold and we prove the existence, uniqueness, and multiplicity of positive solutions of the problem under different conditions.

Using bifurcation techniques, we first prove a global bifurcation theorem for nonlinear second-order semipositone integral boundary value problems. Then the existence and multiplicity of nodal solutions of the above problems are obtained. Finally, an example is worked out to illustrate our main results.

By constructing a special cone in C1[0,2π] and the fixed point theorem, this paper investigates second-order singular semipositone periodic boundary value problems with dependence on the first-order derivative and obtains the existence of multiple positive solutions. Further, an example is given to demonstrate the applications of our main results.

Hepatitis B virus (HBV) infection has been reported to be associated with gastric cancer (GC). Nonetheless, no study has revealed the role of HBV infection in the survival of patients with GC, and the mutation profiles of HBV-infected patients with GC have never been documented. Here, we performed an updated meta-analysis and found a significantly increased risk of GC in HBV-infected individuals (sOR, 1.29; 95% CI, 1.22-1.37). Furthermore, we observed that in the Anhui area, the rate of serum HBsAg positivity (OR, 1.62; 95% CI, 1.03-2.55) was significantly higher in GC patients than in controls. Moreover, our results showed that HBV-positive patients had significantly worse disease-free survival (HR, 1.98; 95% CI, 1.39-2.82) and overall survival (HR, 1.84; 95% CI, 1.19-2.85) than HBV-negative patients. The results of Cox proportional hazards regression proved that HBV infection was an independent adverse prognostic factor in GC. Furthermore, by performing targeted-NGS, we found unique mutation profiles in HBV-infected GC samples, including five frequently mutated protein-coding genes (KMT2B, KMT2D, SOX1, FGF12, and TUBB2B). Expression and survival analyses of these genes identified three novel candidate genes that may have potential roles in GC development. Gene Ontology enrichment analysis showed that the recurrent mutations in HBV-positive GC samples were related to cell proliferation, cell migration, and transcription. Taking together, our study proved that HBV infection is an independent prognostic factor in GC patients. The unique mutation profiles of HBV-infected patients with GC open a new research direction toward the underling mechanism between HBV infection and GC.

Background: Apatinib has a certain efficacy for advanced esophageal squamous cell carcinoma (ESCC). This study aimed to investigate the prognostic significance of platelet (PLT) and platelet to mean platelet volume (PLT/MPV) ratio for advanced ESCC patients with apatinib second-line or late-line treatment. Methods: A retrospective study included 80 patients with advanced ESCC who received Apatinib ≥ 2 lines targeted therapy. We collected baseline clinical characteristics and blood parameters from the patients. Kaplan–Meier plots and univariate and multivariate analysis were used to find the factors related to progression-free survival (PFS). Results: The optimal cut-off values of PLT and PLT/MPV ratio were determined by X-tile software. Kaplan–Meier analysis demonstrated that patients in the high PLT group had better PFS than those in the low PLT group (156 d vs 80 d, P

Osteoporosis, which is characterized by bone loss, increases the risk of fractures and s and seriously affected the amputee’s health. Muscle mass is an important factor affecting bone mineral density (BMD). Muscular atrophy and decreased muscle mass can cause BMD to fall. The bone quantity and quality are used to assess by Microcomputer tomography (micro-CT) with non-destructive. To investigate the performance of micro-CT in evaluating amputation-induced osteopenia in rats, the micro-CT was used to evaluate the change of the microstructure in trabecular bone and cortical bone of amputation. Muscle morphology was analyzed by micro-CT and transmission electron microscopy. Female Sprague–Dawley rats (8 week old) were divided into two groups: control (CON) groups and left hind limb amputation (LHLA). At 35 days, microstructure and volumetric bone mineral density (vBMD) of the tibia and femur were detected through micro-CT. The results showed: (1) the trabecular and cortical vBMD of the proximal tibia and distal femur in the LHLA group were significantly lower than those in the CON group. (2) Compared with the CON group, the trabecular number, bone volume fraction and trabecular thickness of proximal tibia and distal femur in LHLA group decreased significantly, whereas the trabecular separation, structure model index and bone surface/bone volume increased significantly in LHLA group. (3) The whole cross-sectional area (CSA) of whole calf muscles of left limb in LHLA group decreased significantly compared with CON group. In general, hind limb amputation could cause bone loss, changes in the microstructure of trabecular bone and muscle atrophy. Micro-CT is sensitive in evaluating bone microstructure destruction caused by amputation, and can be used for early diagnosis or monitor the development of bone loss in amputation in vivo.

Objective: Poor blood flow supply is an important pathological factor that leads to the development and deterioration of diabetic foot ulcers. This study aims to investigate the acute effects of local vibration with varying intermittent durations on the plantar skin blood flow (SBF) response in diabetic and healthy subjects.Methods: Eleven diabetic patients (7 males, 4 females) and 15 healthy adults (6 males, 9 females) participated in this experiment and accepted three tests. Local continuous vibration (LCV) and two levels of local intermittent vibration (LIV1 and LIV2) were randomly applied to the middle metatarsal head of each subject's right foot in each test. The SBF was measured prior to intervention (Baseline), during Vibration and during the Recovery Stage for each test. The mean SBF in each stage, the change percentages and change rates of SBF in Vibration and Recovery stage among three tests were compared and analyzed for both diabetic and healthy subjects.Results: For diabetic subjects, the SBF was significantly increased in both Vibration and Recovery Stage with local intermittent vibrations (LIV1 and LIV2), but not with LCV. However, there was no significant difference in change percentage and change rate of SBF in diabetic subjects across the three tests. For healthy subjects, all vibration interventions significantly increased the SBF in the Vibration Stage and in the first 1.5 min of the Recovery Stage. Also, the change rate of SBF during the Vibration stage in LIV1 test was significantly greater than that in LIV2 test for healthy subjects. Moreover, change percentage of SBF in Vibration stage of LIV1 test and in some periods of Recovery stages of LIV1 and LIV2 tests for diabetic subjects were lower than for healthy subjects; the absolute change rate of SBF in LIV1 test for diabetic subjects was also lower than for healthy subjects.Conclusion: These findings suggest that both LIV1 and LIV2 may effectively improve SBF in the feet of diabetic people, but LCV may not achieve the same level of vasodilatation. The diabetic subjects were also found to have a lower SBF response to applied vibration than the healthy subjects.

As the most abundant natural flavonoid in rattan tea, dihydromyricetin (DMY) has shown a wide range of pharmacological effects. In addition to the general characteristics of flavonoids, DMY has the effects of cardioprotection, anti-diabetes, hepatoprotection, neuroprotection, anti-tumor, and dermatoprotection. DMY was also applied for the treatment of bacterial infection, osteoporosis, asthma, kidney injury, nephrotoxicity and so on. These effects to some extent enrich the understanding about the role of DMY in disease prevention and therapy. However, to date, we still have no outlined knowledge about the detailed mechanism of DMY, which might be related to anti-oxidation and anti-inflammation. And the detailed mechanisms may be associated with several different molecules involved in cellular apoptosis, oxidative stress, and inflammation, such as AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), protein kinase B (Akt), nuclear factor-κB (NF-κB), nuclear factor E2-related factor 2 (Nrf2), ATP-binding cassette transporter A1 (ABCA1), peroxisome proliferator-activated receptor-γ (PPARγ) and so on. Here, we summarized the current pharmacological developments of DMY as well as possible mechanisms, aiming to push the understanding about the protective role of DMY as well as its preclinical assessment of novel application.