[Study on RF Heating of Implants in Different Conductivity Medium].

In MRI examination, RF heating of implants will affect the safety of implant wearers. The conductivity of various tissues in the human body is significantly different, and the medium conductivity will affect the distribution of the RF electric field. Therefore, it is necessary to study the RF heating of different medium conductivity. Based on the analysis of the principle of MRI RF heating, this study build the model of the bird cage coil, ASTM standard phantom and lead, and the conductivity of several typical human tissues is selected as the conductivity in the experiment. Then calculate the power deposition of the lead at 64 MHz. The results show that the medium conductivity has no effect on the distribution of electric field and power deposition, and the hot spot distribution remains unchanged under different conductivity; The smaller the conductivity is, the larger the power deposition of the lead is, and the greater the temperature rise of the lead caused by RF heating is; The change of conductivity and power deposition is approximately linear. At the limit of 2 W/kg whole body specific absorption rate(SAR), the conductivity decreases, and the wire power deposition increases sharply.

Mechanical response of packings of nonspherical particles: A case study of two-dimensional packings of circulo-lines.

We investigate the mechanical response of jammed packings of circulo-lines in two spatial dimensions, interacting via purely repulsive, linear spring forces, as a function of pressure P during athermal, quasistatic isotropic compression. The surface of a circulo-line is defined as the collection of points that is equidistant to a line; circulo-lines are composed of a rectangular central shaft with two semicircular end caps. Prior work has shown that the ensemble-averaged shear modulus for jammed disk packings scales as a power law, 〈G(P)〉∼P^{ß}, with ß∼0.5, over a wide range of pressure. For packings of circulo-lines, we also find robust power-law scaling of 〈G(P)〉 over the same range of pressure for aspect ratios R≳1.2. However, the power-law scaling exponent ß∼0.8-0.9 is much larger than that for jammed disk packings. To understand the origin of this behavior, we decompose 〈G〉 into separate contributions from geometrical families, G_{f}, and from changes in the interparticle contact network, G_{r}, such that 〈G〉=〈G_{f}〉+〈G_{r}〉. We show that the shear modulus for low-pressure geometrical families for jammed packings of circulo-lines can both increase and decrease with pressure, whereas the shear modulus for low-pressure geometrical families for jammed disk packings only decreases with pressure. For this reason, the geometrical family contribution 〈G_{f}〉 is much larger for jammed packings of circulo-lines than for jammed disk packings at finite pressure, causing the increase in the power-law scaling exponent for 〈G(P)〉.

Aerosol inhalation of ambroxol hydrochloride combined with terbutaline can promote recovery of children with severe pneumonia.

OBJECTIVE: This research aimed to investigate the clinical efficacy of aerosol inhalation of ambroxol hydrochloride combined with terbutaline on children with severe pneumonia, and to evaluate its influence on their immune function and inflammatory level. METHODS: Totally 113 severe pneumonia children were included. Thereinto, 55 children in the control group (CG) were treated with terbutaline aerosol inhalation, while 58 in the research group (RG) were given ambroxol hydrochloride on the basis of the CG. Their symptom alleviating time, blood gas parameters, adverse reactions during treatment, clinical efficacy, immune function and inflammatory factors were compared. RESULTS: The time of fever clearance time, disappearance of cough and pulmonary rates, chest shadow absorption and hospitalization of children in the RG were shorter than those in the CG. The combined treatment did not increase additional adverse reactions; instead, its effective rate was markedly higher than that in the CG. Further research found that after treatment, the arterial partial pressure of oxygen (PaO2), oxygenation index (OI), CD4+ and CD4+/CD8+, and interleukin-10 (IL-10) levels were dramatically increased, while the arterial partial pressure of carbon dioxide (PaCO2), C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-17 (IL-17) and CD8+ levels were obviously increased. In addition, these indexes of children in the RG were obviously better than those in the CG. CONCLUSION: Aerosol inhalation of ambroxol hydrochloride combined with terbutaline has a remarkable clinical efficacy on children with severe pneumonia, which can improve their immune function and reduce inflammatory reaction.

Effectiveness of a pathway-driven eHealth-based integrated care model (PEICM) for community-based hypertension management in China: study protocol for a randomized controlled trial.

BACKGROUND: The prevalence of hypertension is high and increasing in China in recent years. The treatment and control of hypertension calls for long-term management beyond hospital, which is hard to implement in traditional care settings. Integrated care combined with information technology can promote high-quality healthcare services across the life-course. However, few studies have applied a customized integrated care model in community-based hypertension management in China, catering to the emerging "three-manager" mode. This study aims to identify the effectiveness of a pathway-driven eHealth-based integrated model that implemented as a full-featured telehealth system to facilitate standardized management of hypertension in China. METHODS: The trial has been designed as a 1-year, non-blinded superiority trial with two parallel groups. A total of 402 hypertensive patients who meet the eligibility criteria will be recruited and randomized with a 1:1 allocation. All the participants will receive a mobile device for self-management, which is a part of our telehealth system. Participants in the control group will only use the device for BP measurement and receive regular follow-ups from care providers according to the guidelines. Participants in the intervention group will gain full access to the system and receive intervention based on the proposed model (a well-designed coordinated care pathway consisting of 9 tasks). Outcomes will be measured mainly on three occasions (at inclusion, at 6 months, and at 12 months). The primary outcome is mean change in systolic blood pressure over a 12-month period. Secondary outcomes include changes in diastolic blood pressure, biochemical indexes related to hypertension, lifestyles, self-management adherence, and hypertension awareness, as well as work efficiency of care providers. DISCUSSION: This study aims to investigate whether a pathway-driven eHealth-based integrated care model based on the "three-manager" mode will improve hypertension control in China. Success of the model would help improve the quality of present community-based management procedures and benefit more patients with uncontrolled hypertension. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR1900027645 . Registered on November 22, 2019.

Repair of non-traumatic femoral head necrosis by marrow core decompression with bone grafting and porous tantalum rod implantation.

OBJECTIVE: To compare the clinical effects of marrow core decompression with bone grafting and marrow core decompression with porous tantalum rod implantation in treating avascular necrosis of non-traumatic femoral head. METHODS: This prospective study selected 60 patients (74 hips) with avascular necrosis of femoral head admitted to Daping Hospital from January 2018 to March 2019. According to treatment methods, the 60 patients were randomly divided into two groups, i.e. 30 patients in one group were treated by marrow core decompression with bone grafting, and the other 30 patients in the other group were treated with marrow core decompression and porous tantalum rod implantation. RESULTS: All implantation treatments were successful. No significant difference was found in surgical duration, hemorrhage volume and duration of hospitalization stay between the two groups during follow-up. All Harris scores were significantly improved (P<0.05) following treatment compared to those before treatment. The Harris score of patients treated with porous tantalum rod implantation was higher than that of patients treated with bone grafting (P<0.05) after 12 months following treatment and such a difference was significant. CONCLUSION: The combination of marrow core decompression and porous tantalum rod implantation can better improve the functions of hip joints with early femoral head necrosis than marrow core decompression with bone grafting, and can also prevent articular cartilage from collapsing gradually.

SIRT7 Facilitates CENP-A Nucleosome Assembly and Suppresses Intestinal Tumorigenesis.

SIRT7 is a member of the mammalian sirtuins and functions as an NAD+-dependent deacylase. Here we show that SIRT7 deficiency leads to a lowered histone acetyltransferase 1 (HAT1) activity and therefore decreased histone H4K5 and H4K12 acetylation. This in turn causes CENP-A dislocation at the centromere, which further affects chromatin assembly. SIRT7 ablation results in aneuploidy and aging phenotypes, including senescence and nucleolar expansion. Moreover, SIRT7 knockout mice are susceptible to DSS-induced colitis and alcohol-derived epithelial disturbance, revealing a disrupted intestinal epithelial homeostasis. Notably, absence of SIRT7 aggravates the susceptibility of colorectal cancer incidence in APCMin/+ mouse model and elicits further the Wnt signaling. Our findings indicate a tumor suppressive role of SIRT7 in the case of colorectal cancer. Together with the activities in maintaining genome integrity and intestinal homeostasis, activating SIRT7 may serve as a strategy to treat bowel diseases and colorectal cancer.

[Safety Study of Implant Wearers in MRI RF Field Environment].

The complex electromagnetic field environments in magnetic resonance imaging system(MRI) can have a significant impact on patients carrying implants, the RF heating problems being particularly important. To ensure the safety of the patients, it is necessary to understand the distribution of tissue temperature in the MRI environment and its changes over time. Based on the analysis of tissue temperature rise in MRI, this paper constructs a bird cage coil for generating RF field in MRI system, and constructs ASTM standard/improved phantom and single-cavity pacemaker finite element models, use time-domain finite difference (FDTD) to simulate. Firstly, the correctness of the simulation software and simulation method was validated according to the method of ISO. Then the distribution of the electric field, SAR and temperature field and the temperature change with time were calculated in the environment of 64 MHz, 2 W/kg. The difference in temperature rise with blood heat exchange and no blood heat exchange (standard/improved phantom) was specifically compared. The simulation results show that there are electric field and SAR hotspots near the electrode tip, the wire tail and the case of pacemaker. There are high SAR values on both sides of the phantom, and the shorter the distance from the coil, the higher the SAR. The temperature field distribution is similar to the SAR distribution; the temperature is higher in the area around the end of the wire and the case of pacemaker because the heat accumulation is higher around this area. At the same time, blood heat exchange can reduce the temperature rise to a certain extent.

Effects of manganese superoxide dismutase (MnSOD) expression on regulation of esophageal cancer cell growth and apoptosis in vitro and in nude mice.

Manganese superoxide dismutase (MnSOD) catalyzes superoxide radical (O2 (-)) into hydrogen peroxide (H2O2), which is further catalyzed by the combined action of glutathione peroxidase (GPx) and catalase (CAT) into water and oxygen. MnSOD plays a role in cell protection from superoxide damage. This study aimed to investigate the effects of MnSOD on regulation of esophageal squamous cell carcinoma cell growth, apoptosis, and cell cycle distribution in vitro and tumor formation and growth in nude mouse xenografts. The data showed that differential levels of MnSOD expression had different effects on tumor cell proliferation, apoptosis, plating efficiency (PE), and cell cycle distribution in vitro and tumor formation and growth in nude mice. In particular, high levels of MnSOD expression promoted TE-1 cell growth and PE rate in vitro and in nude mice, whereas moderate MnSOD expression suppressed tumor cell growth and PE rate but induced more cell apoptosis. Thus, these data demonstrated the dual effects of MnSOD protein in esophageal squamous cell carcinoma and further study will confirm these current data.

Flavonoid baicalein suppresses adhesion, migration and invasion of MDA-MB-231 human breast cancer cells.

Baicalein is a widely used Chinese herbal medicine that has been used historically in anti-inflammatory and anti-cancer therapy. However, the molecular mechanism of its anti-cancer activity remains poorly understood and warrants further investigations. The purpose of this study is to verify the activity of baicalein to inhibit the invasion of MDA-MB-231 human breast cancer cells. The results indicated that baicalein suppressed MDA-MB-231 cell adhesion to fibronectin-coated substrate, wound healing migration and invasion through the Matrigel in a concentration-dependent manner. Western blot and gelatin zymography analysis showed that baicalein significantly inhibited the expression and secretion of matrix metalloproteinases 2/9 (MMP-2/9) in MDA-MB-231 cells. Additionally, treatment of MDA-MB-231 cells with baicalein down-regulated the expression of MMP-2/9 involved mitogen-activated protein kinases (MAPK) signaling pathway. Taken together, baicalein had potential to suppress the adhesion, migration and invasion of MDA-MB-231 cancer cells in vitro and it could serve as a promising drug for the treatment of cancer metastasis.