Effects of confining pressure and pore pressure on multipole borehole acoustic field in fluid-saturated porous media

In-situ stress is a common stress in the exploration and development of oil reservoirs. Therefore, it is of great significance to study the propagation characteristics of borehole acoustic waves in fluid-saturated porous media under stress.Based on the acoustoelastic theory of fluid-saturated porous media, the field equation of fluid-saturated porous media under the conditions of confining pressure and pore pressure and the acoustic field formula of multipole source excitation in open hole are given. The influences of pore pressure and confining pressure on guided waves of multipole borehole acoustic field in fluid-saturated porous media are investigated. The numerical results show that the phase velocity and excitation intensity of guided wave increase significantly under the confining pressure. For a given confining pressure, the phase velocity of the guided wave decreases with pore pressure increasing. The excitation intensity of guided wave increases at low frequency and then decreases at high frequency with pore pressure increasing, except for that of Stoneley wave which decreases in the whole frequency range. These results will help us get an insight into the influences of confining pressure and pore pressure on the acoustic field of multipole source in borehole around fluid-saturated porous media.

Interplay between mesenchymal stem cells and macrophages:Promoting bone tissue repair

The repair of bone tissue damage is a complex process that is well-orchestrated in time and space,a focus and difficulty in orthopedic treatment.In recent years,the success of mesenchymal stem cells(MSCs)-mediated bone repair in clinical trials of large-area bone defects and bone necrosis has made it a candidate in bone tissue repair engineering and regenerative medicine.MSCs are closely related to macrophages.On one hand,MSCs regulate the immune regulatory function by influencing macrophages proliferation,infiltration,and phenotype polarization,while also affecting the osteoclasts differentiation of macrophages.On the other hand,macrophages activate MSCs and mediate the multilineage differentiation of MSCs by regulating the immune microenvironment.The cross-talk between MSCs and macrophages plays a crucial role in regulating the immune system and in promoting tissue regeneration.Making full use of the relationship between MSCs and macrophages will enhance the efficacy of MSCs therapy in bone tissue repair,and will also provide a reference for further application of MSCs in other diseases.

Enrichment of osteosarcoma stem cells by chemotherapy

Osteosarcoma is the most common primary malignant bone cancer in children and adolescents.Emerging evidence has suggested that the capability of a tumor to grow is driven by a small subset of cells within a tumor,termed cancer stem cells(CSCs).Although several methods have been explored to identify or enrich CSCs in osteosarcoma,these methods sometimes seem impractical,and chemotherapy enrichment for CSCs in osteosarcoma is rarely investigated.In the present study,we found that short exposure to chemotherapy could change the morphology of osteosarcoma cells and increase sarcosphere formation in vitro,as well as increase tumor formation in vivo.Furthermore,methotrexate(MTX)-resistant U2OS/MTX300 osteosarcoma cells were larger in size and grew much more tightly than parental U2OS cells.More importantly,U2OS/MTX300 cells possessed a higher potential to generate sarcospheres in serum-free conditions compared to parental U2OS cells.Also,U2OS/MTX300 cells exhibited the side population(SP)phenotype and expressed CSC surface markers CD117 and Stro-1.Notably,U2OS/MTX300 cells showed a substantially higher tumorigenicity in nude mice relative to U2OS cells.Therefore,we conclude that chemotherapy enrichment is a feasible and practical way to enrich osteosarcoma stem cells.

D-Tyr-tRNA^(Tyr) Deacylase,a New Role in Alzheimer's-associated Disease in SAMP8 Mice

Objective To assess the expression level of D-Tyr-tRNATyr deacylase(DTD) in SAMP8 mice and speculate the function of DTD in disorders associated with Alzheimer's disease(AD).Methods Altogether 12 SAMP8 mice and 12 SAMR1 mice were used in this study.Semi-quantita-tive reverse transcription-polymerase chain reaction(RT-PCR) and Western blot were performed to detect the mRNA and protein levels of DTD in the mice.Purified DTD protein was injected into lateral ventricle to investigate the function of DTD in SAMP mice.The behavior of the mice was tested by using a Step-through Test System.Results Both mRNA and protein levels of DTD were found to be significantly lower in SAMP8 mice compared with those in SAMR1 mice(P<0.05).In vivo injection of DTD protein did not lead to an obvious change in behavior of SAM mice.Conclusions DTD might function in the process of AD-associated pathology and could possibly participate in physiology process in a long-term manner to orchestrate with other regulators in order to maintain the balance of organism.

Expert Survey on the Prevention and Treatment Situation of Traditional Chinese Medicine for Coronary Artery Disease

Objective: To grasp the current situation of Traditional Chinese Medicine (TCM) on prevention and treatment for coronary artery disease (CAD) and the possible advantages and disadvantages. Method: Using a survey in the form of questionnaire among 60 cardiovascular disease experts, to grasp current situation of TCM on prevention and treatment of CAD and the possible advantages and disadvantages. Results: In most areas of China, CAD is common, and angina is the most common clinical type. More than 91% experts choose to integrate traditional and western medicine for treatment and prevention of CAD. TCM proprietary medicine, traditional herbal decoction and intravenous TCM are widely used in the clinical work. Clinical advantages of TCM in the prevention of CAD that are listed in the questionnaire include improving symptoms, enhancing quality of life, increasing exercise tolerance, improving cardiac function, relieving angina, secondary prevention of myocardial infarction, etc. The shortcomings include troublesome brewing of herbal medicine, unpleasant taste of decoction, minimal clinical evidence, slow onset of effects and non-standardized prescription of medicine, etc. Conclusion: The survey reflects the present situation of clinical diagnosis and treatment of TCM on prevention and treatment of CAD to a certain extent;more accurate conclusions need the broader, deeper and large-scale clinical survey.

Differential Cross Sections for the H＋D2O→HD＋OD Reaction： a Full Dimensional State-to-State Quantum Dynamics Study

The time-dependent wave-packet method was employed to calculate the first full-dimensional state-to-state differential cross sections （DCS） for the title reaction with D2O in the ground and the first symmetric （100） and asymmetric stretching （001） excited states. The calculated DCSs for these three initial states are strongly backward peaked at low collision energies. With the increase of collision energy, these DCSs become increasingly broader with the peak position shifting gradually to a smaller angle, consistent with the fact that the title reaction is a direct reaction via an abstraction mechanism. It is found that the （100） and （001） states not only have roughly the same integral cross sections, but also have essentially identical DCS, which are very close to that for the ground state at the same total energy of reaction. The reaction produces a small fraction of OD in the v=1 state, with the population close to the relative reactivity between the ground and vibrationally excited states, therefore confirming the experimental result of Zare et al. and the local mode picture [J. Phys. Chem. 97, 2204 （1993）]. Unexpectedly, the stretching excitation reduces the rotation excitation of product HD at the same total energy.

Cardiac exercise rehabilitation for heart failure:a review of the literature

The most common symptom of patients with heart failure is reduced exercise tolerance,as indicated by decreased peak oxygen uptake(VO2peak),which is associated with both reduced quality of life and survival.Cardiac rehabilitation is a safe and effective treatment for clinically stable patients with heart failure,and is associated with improvements in cardiopulmonary function,muscle strength,physical functional performance,and quality of life.Further,cardiac rehabilitation is associated with a reduction in heart failure hospitalization and mortality.Despite evidence of these benefits,cardiac rehabilitation referral and compliance among patients with heart failure remains low.In this review,we discuss exercise and training program selection for patients with heart failure,including optimal exercise training intensity,and a summary of recent literature on the use of cardiac rehabilitation for patients with heart failure.