764 research outputs found

    Tgif1 Counterbalances The Activity Of Core Pluripotency Factors In Mouse Embryonic Stem Cells

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    Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGF beta/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGF beta/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGF beta/activin/nodal-independent manner.Cancer Prevention Research Institute of Texas (CPRIT) R1106Molecular Bioscience

    Characteristics of Mechanical Ventilation Employed in Intensive Care Units: A Multicenter Survey of Hospitals

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    A 1D point-prevalence study was performed to describe the characteristics of conventional mechanical ventilation in intensive care units (ICUs). In addition, a survey was conducted to determine the characteristics of ICUs. A prospective, multicenter study was performed in ICUs at 24 university hospitals. The study population consisted of 223 patients who were receiving mechanical ventilation or had been weaned off mechanical ventilation within the past 24 hr. Common indications for the initiation of mechanical ventilation included acute respiratory failure (66%), acute exacerbation of chronic respiratory failure (15%) (including tuberculosis-destroyed lung [5%]), coma (13%), and neuromuscular disorders (6%). Mechanical ventilation was delivered via an endotracheal tube in 68% of the patients, tracheostomy in 28% and facial mask with noninvasive ventilation (NIV) in 4%. NIV was used in 2 centers. In patients who had undergone tracheostomy, the procedure had been performed 16.9±8.1 days after intubation. Intensivists treated 29% of the patients. A need for additional educational programs regarding clinical practice in the ICU was expressed by 62% of the staff and 42% of the nurses. Tuberculosis-destroyed lung is a common indication for mechanical ventilation in acute exacerbation of chronic respiratory failure, and noninvasive ventilation was used in a limited number of ICUs

    COMBUSTION CHARACTERISTICS AND EMISSION OF HAZARDOUS AIR POLLUTANTS IN COMMERCIAL FLUIDIZED BED COMBUSTORS FOR SEWAGE SLUDGE

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    Since the disposal of sewage sludge in ocean has been prohibited recently according to London Dumping Convention, technological need for treating sewage sludge safely and efficiently are getting increased in Korea. FBC (Fluidized Bed Combustor) technology has been selected and utilized as one of the alternatives because of combustible content in sludge, on-going process development to maintain the best combustion efficiency, and good heat recovery for energy utilization. In this paper, the process and combustion characteristics of commercially operating FBC incineration plants with the capacity ranging from 50 – 150 tons of sludge per day were investigated by comparing emission data from 4 different plants. Concentrations of hazardous gaseous pollutants (HAPs) such as fine particulate matter, heavy metals, and dioxin from sludge combustion before and after air pollution control devices were measured and analyzed at commercial operating conditions of one typical incinerator. Most of emission data at stack showed under the environmental regulatory limits. Mercury and some heavy metals emission have been reduced significantly as co-beneficial effect since the air pollution control configuration was well arranged and installed to control the regulatory gases such as NOx, SO2, particulates, and dioxin. Sludge, especially generated from industrial plants, contained measurable amounts of acidic materials and heavy metals including Hg. Therefore, such metal emission should receive an attention by monitoring them and further mass balance study for better understanding their fates in the process must proceed in future

    Functional neural differentiation of human adipose tissue-derived stem cells using bFGF and forskolin

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    <p>Abstract</p> <p>Background</p> <p>Adult mesenchymal stem cells (MSCs) derived from adipose tissue have the capacity to differentiate into mesenchymal as well as endodermal and ectodermal cell lineage <it>in vitro</it>. We characterized the multipotent ability of human adipose tissue-derived stem cells (hADSCs) as MSCs and investigated the neural differentiation potential of these cells.</p> <p>Results</p> <p>Human ADSCs from earlobe fat maintained self-renewing capacity and differentiated into adipocytes, osteoblasts, or chondrocytes under specific culture conditions. Following neural induction with bFGF and forskolin, hADSCs were differentiated into various types of neural cells including neurons and glia <it>in vitro</it>. In neural differentiated-hADSCs (NI-hADSCs), the immunoreactivities for neural stem cell marker (nestin), neuronal markers (Tuj1, MAP2, NFL, NFM, NFH, NSE, and NeuN), astrocyte marker (GFAP), and oligodendrocyte marker (CNPase) were significantly increased than in the primary hADSCs. RT-PCR analysis demonstrated that the mRNA levels encoding for ABCG2, nestin, Tuj1, MAP2, NFL, NFM, NSE, GAP43, SNAP25, GFAP, and CNPase were also highly increased in NI-hADSCs. Moreover, NI-hADSCs acquired neuron-like functions characterized by the display of voltage-dependent tetrodotoxin (TTX)-sensitive sodium currents, outward potassium currents, and prominent negative resting membrane potentials under whole-cell patch clamp recordings. Further examination by RT-PCR showed that NI-hADSCs expressed high level of ionic channel genes for sodium (SCN5A), potassium (MaxiK, Kv4.2, and EAG2), and calcium channels (CACNA1C and CACNA1G), which were expressed constitutively in the primary hADSCs. In addition, we demonstrated that Kv4.3 and Eag1, potassium channel genes, and NE-Na, a TTX-sensitive sodium channel gene, were highly induced following neural differentiation.</p> <p>Conclusions</p> <p>These combined results indicate that hADSCs have the same self-renewing capacity and multipotency as stem cells, and can be differentiated into functional neurons using bFGF and forskolin.</p

    Treatment for the Lumbosacral Soft Tissue Defect after Spine Surgery

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    The lumbosacral area is one of the most frequently operated spine regions because of the prevalence of disease in that area. Although a lumbosacral soft tissue defect after surgery due to inflammation and other causes is rare, such soft tissue defects are difficult to treat. Therefore, suitable methods for treating lumbosacral soft tissue defects are necessary. Therefore, this study introduces a case-treated with a transverse lumbosacral rotational flap

    Cellulose-Pectin Spatial Contacts Are Inherent to Never-Dried Arabidopsis Primary Cell Walls: Evidence from Solid-State Nuclear Magnetic Resonance

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    The structural role of pectins in plant primary cell walls is not yet well understood because of the complex and disordered nature of the cell wall polymers. We recently introduced multidimensional solid-state nuclear magnetic resonance spectroscopy to characterize the spatial proximities of wall polysaccharides. The data showed extensive cross peaks between pectins and cellulose in the primary wall of Arabidopsis (Arabidopsis thaliana), indicating subnanometer contacts between the two polysaccharides. This result was unexpected because stable pectin-cellulose interactions are not predicted by in vitro binding assays and prevailing cell wall models. To investigate whether the spatial contacts that give rise to the cross peaks are artifacts of sample preparation, we now compare never-dried Arabidopsis primary walls with dehydrated and rehydrated samples. One-dimensional 13C spectra, two-dimensional 13C-13C correlation spectra, water-polysaccharide correlation spectra, and dynamics data all indicate that the structure, mobility, and intermolecular contacts of the polysaccharides are indistinguishable between never-dried and rehydrated walls. Moreover, a partially depectinated cell wall in which 40% of homogalacturonan is extracted retains cellulose-pectin cross peaks, indicating that the cellulose-pectin contacts are not due to molecular crowding. The cross peaks are observed both at −20°C and at ambient temperature, thus ruling out freezing as a cause of spatial contacts. These results indicate that rhamnogalacturonan I and a portion of homogalacturonan have significant interactions with cellulose microfibrils in the native primary wall. This pectin-cellulose association may be formed during wall biosynthesis and may involve pectin entrapment in or between cellulose microfibrils, which cannot be mimicked by in vitro binding assays.United States. Department of Energy. Office of Basic Energy Sciences (grant no. DE–SC0001090)National Institutes of Health (U.S.) (grant no. EB002026

    Effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution

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    AbstractBackgroundProspective access flow measurement is the preferred method for vascular access surveillance in hemodialysis (HD) patients. We studied the effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution.MethodsAccess flow was measured 30minutes, 120minutes, and 240minutes after the start of HD by ultrasound dilution in 30 patients during 89 HD sessions and evaluated for variation.ResultsThe mean age of the 30 patients was 62±11 years: 19 were male. The accesses comprised 16 fistulae and 14 grafts. The mean access flow over all sessions decreased by 6.1% over time (1265±568mL/min after 30minutes, 1260±599mL/min after 120minutes, and 1197±576mL/min after 240minutes, P<0.01 by repeated measures ANOVA). In addition, a≥5% decrease in mean arterial pressure during HD significantly reduced access flow (P=0.014). However, no other variable (ultrafiltration volume, sex, age, presence of diabetes, type or location of access, body surface area, hemoglobin, serum albumin level) interacted significantly with the effect of time on access flow. Furthermore, mean arterial pressure did not correlate with ultrafiltration volume.ConclusionWe conclude that the variation in access flow during HD is relatively small. Decreased blood pressure is a risk factor for variation in access flow measured by ultrasound dilution. In most patients whose blood pressures are stable during HD, the access flow can be measured at any time during the HD treatment

    The evolution of the nanoscale dissipative structures in a distribution of defects within the isothermally irradiated f.c.c. crystal

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    A kinetic model for the influence of external noises such as fluctuations of the vacancies’ generation rate and inhomogeneity of irradiated f.c.c. crystal on the formation of nanoscale modulated dissipative structure in a spatial distribution of vacancies is considered. The generation rate of vacancies all over the sites and a density of their dislocation-type sinks are modelled as independent random uniform stationary fields and with certain defined parameters of fluctuation correlations— spatial and temporal ones. Such stochastic fields can induce a spatial redistribution of vacancies that can lead to their density stationary uniform field or stochastic one. By the average value and correlation functions of these fluctuations, the conditions are determined for interacting fluctuations of the vacancies’ density, under which this homogeneous random field becomes unstable in relation to the stochastic field with a spatially periodic mean distribution of vacancies’ density. For instance, with f.c.c. nickel as a model of the irradiated functional material, the temperature dependence of spatial period d(T) of the modulated dissipative structure of vacancies’ subsystem in f.c.c. crystal is numerically forecasted and analysed, taking into account the total (‘electrochemical’ + ‘straininduced’) interaction between vacancies. Such d(T)-dependence is also determined by the kinetic characteristics of vacancies’ redistribution.The Ministry of Science and Technology, Koreahttp://www.tandfonline.com/loi/tphm202015-05-30hb201

    Visible emission from Ce-doped ZnO nanorods grown by hydrothermal method without a post thermal annealing process

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    Visible light-emitting Ce-doped ZnO nanorods [NRs] without a post thermal annealing process were grown by hydrothermal method on a Si (100) substrate at a low temperature of 90°C. The structural investigations of Ce-doped ZnO NRs showed that the Ce3+ ions were successfully incorporated into the ZnO lattice sites without forming unwanted Ce-related compounds or precipitates. The optical investigation by photoluminescence spectra shows that the doped Ce3+ ions in the ZnO NRs act as an efficient luminescence center at 540 nm which corresponds to the optical transition of 5d → 4f orbitals in the Ce3+ ions. The photoluminescence intensity of the Ce-doped ZnO NRs increased with the increasing content of the Ce-doping agent because the energy transfer of the excited electrons in ZnO to the Ce3+ ions would be enhanced by increased Ce3+ ions
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