799 research outputs found

    Transplantation of Endothelial Progenitor Cells as Therapeutics for Cardiovascular Diseases

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    [[abstract]]With better understanding of endothelial progenitor cells (EPCs), many therapeutic approaches to cardiovascular diseases have been developed. This article will review novel research of EPCs in promoting angiogenesis, vasculogenesis, and endothelialization, as a design for future clinical treatment. Cell therapy has the potential to supply stem/progenitor cells and multiple angiogenic factors to the region of ischemia. The efficacy of EPC transplantation may be impaired by low survival rate, insufficient cell number, and impaired function in aging and diseases. Combination of EPCs or cells primed with growth factors or genetic modification may improve the therapeutic efficacy. The molecular mechanism involved in EPC repairing processes is essential. Thus, we have also addressed the molecular mechanism of mobilization, homing, and differentiation of EPCs. The potential of therapeutic neovascularization, angiogenic factor therapy, and cell transplantation have been elucidated. Based on past experience and actual knowledge, future strategies for EPC therapy will be proposed in order to fully exploit the potential of EPC transplantation with clinical relevance for cardiovascular disease applications

    Characterization and System Identification of XY Flexural Mechanism Using Double Parallelogram Manipulator for High Precision Scanning

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    This article represents modeling of double parallelogram flexural manipulator derived from basic classical mechanics theory. Fourth order vibration wave equation is used for mathematical modeling and its performance is determined for step input and sinusoidal forced input. Static characterization of DFM is carried out to determine stiffness and force deflection characteristics over the entire motion range and dynamic characteristics is carried out using Transient response and Frequency response. Transient response is determined using step input to DFM which gives system properties such as damping, rise time and settling time. These parameters are then compared with theoretical model presented previously. Frequency response of DFM system gives characteristics of system with different frequency inputs which is used for experimental modeling of DFM device. Here, Voice Coil Motor is used as Actuator and optical encoder is used for positioning sensing of motion stage. It is noted that theoretical model is having 5% accuracy with experimental results. To achieve better position and accuracy, PID and LQR (Linear Quadratic Regulator) implementation was carried out on experimental model. PID gains are optimally tuned by using Ziegler Nichols approach. PID control is implemented experimentally using dSPACE DS1104 microcontroller and Control Desk software. Experimentally, it is observed that positioning accuracy is less than 5 μm. Further multiple DFM blocks are arranged for developing XY flexural mechanism and static characterization was carried out on it. The comparison of experimental and FEA results for X-direction and Y-direction is presented at end of paper

    Nearly Monodispersion CoSm Alloy Nanoparticles Formed by an In-situ Rapid Cooling and Passivating Microfluidic Process

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    An in siturapid cooling and passivating microfluidic processhas been developed for the synthesis of nearly monodispersed cobalt samarium nanoparticles (NPs) with tunable crystal structures and surface properties. This process involves promoting the nucleation and growth of NPs at an elevated temperature and rapidly quenching the NP colloids in a solution containing a passivating reagent at a reduced temperature. We have shown that Cobalt samarium NPs having amorphous crystal structures and a thin passivating layer can be synthesized with uniform nonspherical shapes and size of about 4.8 nm. The amorphous CoSm NPs in our study have blocking temperature near 40 K and average coercivity of 225 Oe at 10 K. The NPs also exhibit high anisotropic magnetic properties with a wasp-waist hysteresis loop and a bias shift of coercivity due to the shape anisotropy and the exchange coupling between the core and the thin oxidized surface layer

    Student and tutor perceptions on attributes of effective problems in problem-based learning

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    This study aimed to identify the attributes that students and tutors associated with effective PBL problems, and assess the extent to which these attributes related to the actual effectiveness of problems. To this end, students and tutors in focus groups were asked to discuss about possible attributes of effective problems. The same participants were then asked to individually and independently judge eight sample problems they had worked with. Text analysis of the focus group discussion transcripts identified eleven problem attributes. Participants' judgments of the sample problems were then frequency-scored on the eleven problem attributes. Relating the participants' judgments with the entire student cohort's grades yielded high and significant correlations, suggesting that the eleven problem attributes reflect aspects of problem effectiveness

    Modification of conservative treatment of heterotopic cervical pregnancy by Foley catheter balloon fixation with cerclage sutures at the level of the external cervical os: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Conservative treatment of a heterotopic cervical pregnancy was performed with a modification of the fixation of a Foley catheter at the level of the external cervical os, followed by the ligature of the descending cervical branches of the uterine arteries and systemic methotrexate application.</p> <p>Case presentation</p> <p>A 34-year-old Caucasian woman was diagnosed with double gestation after 6 weeks of <it>in vitro </it>fertilization treatment. A gynecological examination and color Doppler ultrasound scan revealed intra-uterine and cervical gestational sacs both containing live fetuses. A Foley catheter balloon was inserted into the cervical canal, inflated and fixed by a cerclage suture at the level of the external cervical os, followed by ligation of the descending cervical branches of the uterine arteries. Systemic methotrexate was applied. Three days after removal of the Foley catheter, an evacuation of the intra-uterine gestational sac was performed. Hemorrhage from the implantation site was controlled immediately and a pregnancy termination was successfully performed. The procedure was uneventful and our patient was discharged with a preserved uterus.</p> <p>Conclusions</p> <p>Conservative treatment of cervical pregnancy using a Foley catheter balloon is more efficacious if the Foley catheter balloon is attached in the correct position with a cerclage suture at the level of the external os, followed by ligation of the descending cervical branches of the uterine arteries, thereby exerting maximal pressure on the bleeding vessels.</p

    Risk Factors for Nonsynchronous Second Primary Malignancy and Related Death in Patients with Differentiated Thyroid Carcinoma

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    BACKGROUND: Differentiated thyroid cancer (DTC) survivors are at increased risk of developing nonsynchronous second primary malignancy (NSPM). This study aims to examine possible risk factors leading to occurrence of NSPM as well as risk factors leading to NSPM-related death in patients with DTC. METHODS: Of the 1,106 patients with DTC managed at our institution, 92 (8.3%) patients developed NSPM and 40 (3.6%) patients died of NSPM. All causes of death were confirmed by medical record, autopsy report or death certificate. Clinicopathological variables were compared between those without NSPM and with NSPM as well as between those who died of NSPM and did not die of NSPM. Significant variables on univariate analysis were entered into a Cox proportional hazards model. RESULTS: The median latency period from diagnosis of DTC to NSPM was 142.7 (range 16.8-511.0) months. For occurrence of NSPM, age at DTC diagnosis >/=50 years old [relative risk (RR) = 2.35], cumulative radioactive iodine (RAI) activity 3.0-8.9 GBq (RR = 2.38), and external local radiotherapy (ERT) (RR = 1.95) were significant risk factors. For NSPM-related death, age at DTC diagnosis >/=50 years old (RR = 3.32) and nonbreast cancer (RR = 5.76) were significant risk factors. CONCLUSIONS: NSPM accounted for 18.7% of all deaths in DTC, but mortality was high (43.5%). Age at DTC diagnosis >/=50 years old, cumulative RAI activity 3.0-8.9 GBq, and ERT were significant risk factors for occurrence of NSPM, whereas age at DTC diagnosis >/=50 years old and the diagnosis of nonbreast cancer were significant risk factors for NSPM-related death.published_or_final_versionSpringer Open Choice, 21 Feb 201

    Immunogenicity of intradermal trivalent influenza vaccine with topical imiquimod: a doubleblind randomised controlled trial

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    BACKGROUND: Imiquimod, a synthetic toll-like receptor 7-agonist enhanced immunogenicity of influenza vaccine in a mouse model. We hypothesised that topical imiquimod before intradermal trivalent influenza vaccination (TIV) will produce similar effect in human ...postprin

    Being young in a changing world: how temperature and salinity changes interactively modify the performance of larval stages of the barnacle Amphibalanus improvisus

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    The fate of key species, such as the barnacle Amphibalanus improvisus, in the course of global change is of particular interest since any change in their abundance and/or performance may entail community-wide effects. In the fluctuating Western Baltic, species typically experience a broad range of environmental conditions, which may preselect them to better cope with climate change. In this study, we examined the sensitivity of two crucial ontogenetic phases (naupliar, cypris) of the barnacle toward a range of temperature (12, 20, and 28°C) and salinity (5, 15, and 30 psu) combinations. Under all salinity treatments, nauplii developed faster at intermediate and high temperatures. Cyprid metamorphosis success, in contrast, was interactively impacted by temperature and salinity. Survival of nauplii decreased with increasing salinity under all temperature treatments. Highest settlement rates occurred at the intermediate temperature and salinity combination, i.e., 20°C and 15 psu. Settlement success of “naive” cyprids, i.e., when nauplii were raised in the absence of stress (20°C/15 psu), was less impacted by stressful temperature/salinity combinations than that of cyprids with a stress history. Here, settlement success was highest at 30 psu particularly at low and high temperatures. Surprisingly, larval survival was not highest under the conditions typical for the Kiel Fjord at the season of peak settlement (20°C/15 psu). The proportion of nauplii that ultimately transformed to attached juveniles was, however, highest under these “home” conditions. Overall, only particularly stressful combinations of temperature and salinity substantially reduced larval performance and development. Given more time for adaptation, the relatively smooth climate shifts predicted will probably not dramatically affect this species
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