4,143 research outputs found
Report of the panel on volcanology, section 4
Two primary goals are identified as focal to NASA's research efforts in volcanology during the 1990s: to understand the eruption of lavas, gases, and aerosols from volcanoes, the dispersal of these materials on the Earth's surface and through the atmosphere, and the effects of these eruptions on the climate and environment; and to understand the physical processes that lead to the initiation of volcanic activity, that influence the styles of volcanic eruptions, and that dictate the morphology and evolution of volcanic landforms. Strategy and data requirements as well as research efforts are discussed
The emergence of <i>Pax7</i>-expressing muscle stem cells during vertebrate head muscle development
Pax7 expressing muscle stem cells accompany all skeletal muscles in the body and in healthy individuals, efficiently repair muscle after injury. Currently, the in vitro manipulation and culture of these cells is still in its infancy, yet muscle stem cells may be the most promising route towards the therapy of muscle diseases such as muscular dystrophies.It is often overlooked that muscular dystrophies affect head and body skeletal muscle differently. Moreover, these muscles develop differently. Specifically, head muscle and its stem cells develop from the non-somitic head mesoderm which also has cardiac competence. To which extent head muscle stem cells retain properties of the early head mesoderm and might even be able to switch between a skeletal muscle and cardiac fate is not known. This is due to the fact that the timing and mechanisms underlying head muscle stem cell development are still obscure. Consequently, it is not clear at which time point one should compare the properties of head mesodermal cells and head muscle stem cells.To shed light on this, we traced the emergence of head muscle stem cells in the key vertebrate models for myogenesis, chicken, mouse, frog and zebrafish, using Pax7 as key marker. Our study reveals a common theme of head muscle stem cell development that is quite different from the trunk. Unlike trunk muscle stem cells, head muscle stem cells do not have a previous history of Pax7 expression, instead Pax7 expression emerges de-novo. The cells develop late, and well after the head mesoderm has committed to myogenesis. We propose that this unique mechanism of muscle stem cell development is a legacy of the evolutionary history of the chordate head mesoderm
Classroom Societies and Common Markets: The Gem Fair
In-class societies such as the Mini-Society an
Activation of a Translocated Human c-\u3ci\u3emyc\u3c/i\u3e Gene by an Enhancer in the Immunoglobulin Heavy-Chain Locus
A tissue-specific transcriptional enhancer element that is associated with the human immunoglobulin heavy-chain locus is defined. In a non-Hodgkin’s lymphoma that contains a translocated c-myc gene this enhancer is retained on the 14q+ chromosome and occurs within sequences shown to activate previously cryptic promoters of the c-myc gene
Effects of consumer demand, product lifetime, and substitution ratio on perishable inventory management
With the intensification of global population, food security is a big concern. Food waste stems from inappropriate inventory management. Companies offer a wide range of products to capture more sales, yet this increases inventories and complicates inventory management. Management challenges are worsened by three factors: uncertain consumer demand, product lifetimes, and consumer substitution among the product range. This research aims to understand the effects of these factors on inventory performance. The analytic hierarchy process (AHP) method was used to weight the importance of each of the non-financial performance measures from the simulation results and data envelopment analysis (DEA) was used to rank and evaluate the scenarios. Then, the most favorable scenario or replenishment policy, which had the lowest DEA efficiency score, was chosen. The results show that when the substitution ratio is greater, its interaction with consumer demand and product lifetime has mostly a small- or medium-sized effect on retailers’ performance, in contrast to relatively larger effects on the supplier. These findings show that suppliers’ performance is affected largely by the existence of the bullwhip effect in the model. Recommendations are provided for managers who are facing uncertainties of consumer demand, substitution, and product lifetime
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Simultaneous Measurements of Atmospheric HONO and NO2 via Absorption Spectroscopy using Tunable Mid-Infrared Continuous-wave Quantum Cascade Lasers
Nitrous acid (HONO) is important as a significant source of hydroxyl radical (OH) in the troposphere and as a potent indoor air pollutant. It is thought to be generated in both environments via heterogeneous reactions involving nitrogen dioxide . In order to enable fast-response HONO detection suitable for eddy-covariance flux measurements and to provide a direct method that avoids interferences associated with derivatization, we have developed a 2-channel tunable infrared laser differential absorption spectrometer (TILDAS) capable of simultaneous high-frequency measurements of HONO and NO2. Beams from two mid-infrared continuous-wave mode quantum cascade lasers (cw-QCLs) traverse separate 210 m paths through a multi-pass astigmatic sampling cell at reduced pressure for the direct detection of HONO and . The resulting one-second detection limits (S/N=3) are 300 and 30 ppt (pmol/mol) for HONO and , respectively. Our HONO quantification is based on revised line-strengths and peak positions for cis-HONO in the 6-micron spectral region that were derived from laboratory measurements. An essential component of ambient HONO measurements is the inlet system and we demonstrate that heated surfaces and reduced pressure minimize sampling artifacts.Earth and Planetary SciencesEngineering and Applied Science
Morally Respectful Listening and its Epistemic Consequences
What does it mean to listen to someone respectfully, that is, insofar as they are due recognition respect? This paper addresses that question and gives the following answer: it is to listen in such a way that you are open to being surprised. A specific interpretation of this openness to surprise is then defended
Chemotherapy and Stem Cell Transplantation Increase p16
AbstractThe expression of markers of cellular senescence increases exponentially in multiple tissues with aging. Age-related physiological changes may contribute to adverse outcomes in cancer survivors. To investigate the impact of high dose chemotherapy and stem cell transplantation on senescence markers in vivo, we collected blood and clinical data from a cohort of 63 patients undergoing hematopoietic cell transplantation. The expression of p16INK4a, a well-established senescence marker, was determined in T-cells before and 6months after transplant. RNA sequencing was performed on paired samples from 8 patients pre- and post-cancer therapy. In patients undergoing allogeneic transplant, higher pre-transplant p16INK4a expression was associated with a greater number of prior cycles of chemotherapy received (p=0.003), prior autologous transplantation (p=0.01) and prior exposure to alkylating agents (p=0.01). Transplantation was associated with a marked increase in p16INK4a expression 6months following transplantation. Patients receiving autologous transplant experienced a larger increase in p16INK4a expression (3.1-fold increase, p=0.002) than allogeneic transplant recipients (1.9-fold increase, p=0.0004). RNA sequencing of T-cells pre- and post- autologous transplant or cytotoxic chemotherapy demonstrated increased expression of transcripts associated with cellular senescence and physiological aging. Cytotoxic chemotherapy, especially alkylating agents, and stem cell transplantation strongly accelerate expression of a biomarker of molecular aging in T-cells
Bisantrene (NSC 337766) (CL 216,942) in advanced breast cancer
Bisantrene (NSC 337766) is an anthracenedicarboxaldehyde hydrazone demonstrating a wide spectrum of activity in animal tumor model systems with no evidence of cardiotoxicity or alopecia, in contrast to doxorubicin. Thirty-three women with advanced adenocarcinoma of the breast were treated with 260 mg/m 2 IV every 3 weeks. All patients had received at least one prior combination chemotherapy regimen for metastatic disease and 32/33 were refractory to doxorubicin. Of 28 patients evaluable for response one had a partial response lasting 10 weeks and three patients had stable disease for 22, 22, and 9 weeks. The most significant toxicities were nonhematologic: nausea and vomiting (41%), phlebitic reactions (38%), hypotension, one fatal anaphylactic reaction, and the development of a 7th cranial nerve palsy during drug infusion. Hematologic toxicity, leukopenia, was dose-limiting but manageable without associated infections or bleeding. These results indicate that bisantrene in this dose and schedule is not a useful drug in heavily pretreated breast cancer patients. The incidence and severity of phlebitic reactions limited venous access and adversely affected patient compliance. Preliminary results of other phase II breast cancer trials indicate a similar spectrum of toxicity but suggest more significant antitumor activity even in patients previously treated with doxorubicin. Trials conducted in patients with minimal prior treatment and with bisantrene administered via central line appear warranted for definitive assessment of the activity of this agent in breast cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46914/1/280_2004_Article_BF00269035.pd
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