2,757 research outputs found
Computational Fluid Dynamics (cfd) Modeling of a Laboratory Scale Coal Gasifier
Furthering gasification technology is an essential part of advancing clean coal technologies. In order to seek insight into the appropriate operations for the formation of synthetic gas (syngas) a numerical simulation was performed to predict the phenomena of coal gasification in a laboratory scale entrained-flow coal gasifier. The mesh for the model was developed with ICEM CFD software and the chemical and physical phenomena were modeled using the fluid flow solver ANSYS FLUENT. Mesh independence was verified. The model was validated with experimental data from several studies performed on a laboratory scale gasifier.
Systematic examination of the model was performed by varying primary and secondary inlet concentrations of steam and oxygen in regular intervals. Studies were also performed to investigate the effects of coal particle size and steam preheat temperatures. The effect of the turbulence model was also investigated by employing two turbulence models.
Of the two turbulence models used the standard k-ε model showed the best agreement with experimental data. Model predictions found that increasing the steam concentration or preheat temperatures in the secondary inlet generally decreases production, while increasing and concentrations. Increasing the steam content in the secondary inlet showed no signifigants effects on predicted temperatures in the gasifier. Increasing the oxygen concentration in the primary inlet generally increases exit temperatures, , and production, while decreasing concentrations.It was found that decreasing the particle size increases the , , and concentration, while decreasing the concentrations
Environmental performance with agronomic management: Raccoon River watershed case study
Accurate information about water quality trends in agricultural watersheds is needed to inform agricultural policy and quantify the effectiveness of field and landscape management practices. Several studies predicted the increased conversion of soybean and pasture acres to more corn acres driven by corn ethanol production would increase N losses and river nitrate-nitrogen
Health Behaviors Predicting Risk of Obesity in US Adults: What Does a Healthy Lifestyle Look Like?
Objective
The purpose of this study was to examine the association between lifestyle factors and body weight in a nationally representative sample of US adults and to evaluate the association between a novel “Healthy Habits Composite Score (HHCS)” and risk of obesity. Methods
This cross-sectional study included data from 4870 adults who participated in the 2017–2018 National Health and Nutrition Examination Survey (NHANES). The HHCS was developed based on 4 factors: diet, physical activity, sedentary time, and sleep, all of which were measured during the NHANES. A “healthy lifestyle” was defined as meeting ≥3 of the 4 established criteria. Data analysis was conducted using SAS 9.4 and procedures to account for the complex survey design. All models were adjusted for age, sex, race, household income, and education. Results
Adults with obesity had significantly lower dietary quality (48.8 ± 0.6 vs. 53.2 ± 0.9) and reported significantly more sedentary time (∼1 h more; 356.3 ± 7.0 vs. 301.4 ± 8.3 min) than lean adults, both p \u3c 0.001. Achieving a healthy lifestyle based on the HHCS was associated with nearly double the odds of having a healthy body weight (OR 1.9, p \u3c 0.001). Conclusions
Following a lifestyle focused on healthy habits (diet quality, physical activity, limited sedentary time, and sleep) was strongly associated with a decreased risk of obesity: an individual who achieved three or more healthy habits had nearly twice the odds of having a healthy body weight. Therefore, comprehensive interventions that address and promote a wide range of healthy habits may be most effective for lowering obesity risk
THE OUTCOME OF ATG ON THE STEM CELL TRANSPLANTS FROM MATCHED UNRELATED DONOR, A SINGLE INSTITUTE EXPERIENCE
poster abstractBACKGROUND: Antithymocyte globulin (ATG) was found to decrease the morbidity of stem cell transplant (SCT) from matched unrelated donor (MUD) by decreasing the incidence of chronic graft vs host disease cGvHD, and at high doses, acute GvHD. We reviewed our results of MUD transplants where ATG was incorporated into the preparative regimen, and compared the results to patients prior to September 2006 where ATG was not used. The primary endpoints were the effect on GvHD and lethal infectious complications.
Method: All stem cell transplants from MUD performed after 2000 at IU hospital for treatment of hematological malignancies using a myelo-ablative regimen were retrospectively reviewed.
Result: between 1/2000 and 3/2009 seventy nine stem cell transplants were conducted using stem cells from MUD. 28 patients received ATG at a total dose of 7.5mg/kg vs 51 patients who did not receive ATG. Both groups were matched in term of age, sex, underline malignancies, degree of HLA-match, CMV serology, and conditioning regimens. Ninety-six percent of patient in ATG group received prophylaxis for GvHD using FK506/Sirolimus vs 14% in the no ATG group where a methotrexate based treatment was used (P<0.0001). The rate of Grade II-VI acute GVHD at day 100 was significantly lower in the ATG group compare to no ATG (14% vs 39%, P =0.011). Although however, the rate of chronic GVHD at 1 year was higher in ATG group than in the no ATG group, this was statistically not significant
(43% and 23%; P=0.2). The rates of overall fungal infections and lethal fungal infections were comparable (14% and 10%) for ATG vs (17% and 11%) for no ATG (p =0.70). The rate of primary CMV infection (i.e., in patient not receiving corticosteroid treatment for GVHD) was higher in ATG group, although not statistically significant (31% vs 17%, P=0.27). Day 100 mortality was 15% and 25% in ATG and no ATG group respectively, overall survival at 1 and 2 years was 47% and 31% for ATG group vs 49% and 36% for no ATG group (P>0.05), Median time to death was 8.6 months (CI95%, 1.8-15.4) and 11.9 months (CI95%, 8-15.7) with P=0.7. The mortality from GVHD at 4 months was 0% in ATG group vs 12% in no ATG group (P =0.08).While the mortality rate from bacterial infection and sepsis were equivalent, more patients in the ATG group who did not receiving corticosteroid treatment for aGVHD died from viral and fungal infection (15% vs 0% at 8 months, P=0.013).
Summary: While ATG was associated with a trend toward lower mortality rate at day 100 due to statistically significant decrease in incidence and mortality of aGVHD, it was associated with increase rate of delayed-onset acute GVHD and statistically significant high rate of lethal viral and fungal infection leading to similar overall survival at 1 and 2 years. This study demonstrates the lack of overall benefit of ATG at dose of 7.5mg/kg. Further study to investigate the outcome of using lower doses of ATG to lower the rate of lethal infections while still reducing the risk of GvHD is recommended
Ecological succession of a Jurassic shallow-water ichthyosaur fall.
After the discovery of whale fall communities in modern oceans, it has been hypothesized that during the Mesozoic the carcasses of marine reptiles created similar habitats supporting long-lived and specialized animal communities. Here, we report a fully documented ichthyosaur fall community, from a Late Jurassic shelf setting, and reconstruct the ecological succession of its micro- and macrofauna. The early 'mobile-scavenger' and 'enrichment-opportunist' stages were not succeeded by a 'sulphophilic stage' characterized by chemosynthetic molluscs, but instead the bones were colonized by microbial mats that attracted echinoids and other mat-grazing invertebrates. Abundant cemented suspension feeders indicate a well-developed 'reef stage' with prolonged exposure and colonization of the bones prior to final burial, unlike in modern whale falls where organisms such as the ubiquitous bone-eating worm Osedax rapidly destroy the skeleton. Shallow-water ichthyosaur falls thus fulfilled similar ecological roles to shallow whale falls, and did not support specialized chemosynthetic communities
The metabolic environment of the developing embryo: A multidisciplinary approach on oilseed rapeseed
Brassicaceae seeds consist of three genetically distinct structures: the embryo, endosperm and seed coat, all of which are involved in assimilate allocation during seed development. The complexity of their metabolic interrelations remains unresolved to date. In the present study, we apply state-of-the-art imaging and analytical approaches to assess the metabolic environment of the Brassica napus embryo. Nuclear magnetic resonance imaging (MRI) provided volumetric data on the living embryo and endosperm, revealing how the endosperm envelops the embryo, determining endosperm's priority in assimilate uptake from the seed coat during early development. MRI analysis showed higher levels of sugars in the peripheral endosperm facing the seed coat, but a lower sugar content within the central vacuole and the region surrounding the embryo. Feeding intact siliques with 13C-labeled sucrose allowed tracing of the post-phloem route of sucrose transfer within the seed at the heart stage of embryogenesis, by means of mass spectrometry imaging. Quantification of over 70 organic and inorganic compounds in the endosperm revealed shifts in their abundance over different stages of development, while sugars and potassium were the main determinants of osmolality throughout these stages. Our multidisciplinary approach allows access to the hidden aspects of endosperm metabolism, a task which remains unattainable for the small-seeded model plant Arabidopsis thaliana
Imaging Active Infection in vivo Using D-Amino Acid Derived PET Radiotracers.
Occult bacterial infections represent a worldwide health problem. Differentiating active bacterial infection from sterile inflammation can be difficult using current imaging tools. Present clinically viable methodologies either detect morphologic changes (CT/ MR), recruitment of immune cells (111In-WBC SPECT), or enhanced glycolytic flux seen in inflammatory cells (18F-FDG PET). However, these strategies are often inadequate to detect bacterial infection and are not specific for living bacteria. Recent approaches have taken advantage of key metabolic differences between prokaryotic and eukaryotic organisms, allowing easier distinction between bacteria and their host. In this report, we exploited one key difference, bacterial cell wall biosynthesis, to detect living bacteria using a positron-labeled D-amino acid. After screening several 14C D-amino acids for their incorporation into E. coli in culture, we identified D-methionine as a probe with outstanding radiopharmaceutical potential. Based on an analogous procedure to that used for L-[methyl-11C]methionine ([11C] L-Met), we developed an enhanced asymmetric synthesis of D-[methyl-11C]methionine ([11C] D-Met), and showed that it can rapidly and selectively differentiate both E. coli and S. aureus infections from sterile inflammation in vivo. We believe that the ease of [11C] D-Met radiosynthesis, coupled with its rapid and specific in vivo bacterial accumulation, make it an attractive radiotracer for infection imaging in clinical practice
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