In-flight simulation investigation of rotorcraft pitch-roll cross coupling

An in-flight simulation experiment investigating the handling qualities effects of the pitch-roll cross-coupling characteristic of single-main-rotor helicopters is described. The experiment was conducted using the NASA/Army CH-47B variable stability helicopter with an explicit-model-following control system. The research is an extension of an earlier ground-based investigation conducted on the NASA Ames Research Center's Vertical Motion Simulator. The model developed for the experiment is for an unaugmented helicopter with cross-coupling implemented using physical rotor parameters. The details of converting the model from the simulation to use in flight are described. A frequency-domain comparison of the model and actual aircraft responses showing the fidelity of the in-flight simulation is described. The evaluation task was representative of nap-of-the-Earth maneuvering flight. The results indicate that task demands are important in determining allowable levels of coupling. In addition, on-axis damping characteristics influence the frequency-dependent characteristics of coupling and affect the handling qualities. Pilot technique, in terms of learned control crossfeeds, can improve performance and lower workload for particular types of coupling. The results obtained in flight corroborated the simulation results

Audit of burns patients in the intensive care setting [poster]

No abstract available

Audit of burns patients in the intensive care setting [poster]

No abstract available

Brainstem metastases treated with Gamma Knife stereotactic radiosurgery: the Indiana University Health experience

Brainstem metastases offer a unique challenge in cancer treatment, yet stereotactic radiosurgery (SRS) has proven to be an effective modality in treating these tumors. This report discusses the clinical outcomes of patients with brainstem metastases treated at Indiana University with Gamma Knife (GK) radiosurgery from 2008 to 2016. 19 brainstem metastases from 14 patients who had follow-up brain imaging were identified. Median tumor volume was 0.04 cc (range: 0.01-2.0 cc). Median prescribed dose was 17.5 Gy to the 50% isodose line (range: 14-22 Gy). Median survival after GK SRS treatment to brainstem lesion was 17.2 months (range: 2.8-45.6 months). The experience at Indiana University confirms the safety and efficacy of range of GK SRS prescription doses (14-22 Gy) to brainstem metastases

Modelling of root reinforcement and erosion control by ‘Veronese’ poplar on pastoral hill country in New Zealand

Background The control of erosion processes is an important issue worldwide. In New Zealand, previous studies have shown the benefits of reforestation or bioengineering measures to control erosion. The impetus for this work focuses on linking recent research to the needs of practitioners by formulating quantitative guidelines for planning and evaluation of ground bioengineering stabilisation measures. Methods Two root distribution datasets of ‘Veronese’ poplar (Populus deltoides x nigra) were used to calibrate a root distribution model for application on single root systems and to interacting root systems at the hillslope scale. The root distribution model results were then used for slope stability calculations in order to quantitatively evaluate the mechanical stabilisation effects of spaced trees on pastoral hillslopes. Results This study shows that root distribution data are important inputs for quantifying root reinforcement at the hillslope scale, and that root distribution strongly depends on local environmental conditions and on the tree planting density. The results also show that the combination of soil mechanical properties (soil angle of internal friction and cohesion) and topographic conditions (slope inclination) are the major parameters to define how much root reinforcement is needed to stabilise a specific slope, and thus the spacing of the trees to achieve this. Conclusions For the worst scenarios, effective root reinforcement (>2 kPa) is reached for tree spacing ranging from 2500 stems per hectare (sph) for 0.1 m stem diameter at breast height (DBH) to 300 sph for 0.3 m stem DBH. In ideal growing conditions, tree spacing less than 100 sph is sufficient for stem DBH greater than 0.15 m. New quantitative information gained from this study can provide a basis for evaluating planting strategies using poplar trees for erosion control on pastoral hill country in New Zealand

Effectiveness of Efavirenz-Based Regimens in Young HIV-Infected Children Treated for Tuberculosis: A Treatment Option for Resource-Limited Settings

Background: Antiretroviral treatment (ART) options for young children co-infected with HIV and tuberculosis are limited in resource-poor settings due to limited data on the use of efavirenz (EFV). Using available pharmacokinetic data, an EFV dosing schedule was developed for young co-infected children and implemented as the standard of care at Macha Hospital in Southern Province, Zambia. Treatment outcomes inchildren younger than 3 years of age or weighing less than 10 kg receiving either EFV-based ART plus anti-tuberculous treatment or nevirapine-based (NVP) ART were compared. Methods: Treatment outcomes were measured in a cohort of HIV-infected children seeking care at Macha Hospital in rural Zambia from 2007 to 2010. Informationon the diagnosis and treatment of tuberculosis was abstracted from medical records. Results: Forty-five children treated for tuberculosis initiated an EFV-based regimen and 69 children initiated a NVP-based regimen, 7 of whom also were treated for tuberculosis. Children receiving both regimens were comparable in age, but children receiving EFV started ART with a lower CD4+ T-cell percentage and weight-for-age z-score. Children receiving EFV experienced increases in both CD4+ T-cell percentage and weight-for-age z-score during follow-up, such that levels were comparable to children receiving NVP after two years of ART. Cumulative survival after 12 months of ART did not differ between groups (NVP:87%;EFV:80%;p = 0.25). Eleven children experienced virologic failure during follow-up.The adjusted hazard ratio of virologic failure comparing EFV to NVP was 0.25 (95% CI:0.05,1.24) and 0.13 (95% CI:0.03,0.62) using thresholds of 5000 and 400 copies/mL, respectively.Five children receiving EFV were reported to have had convulsions after ART initiation compared to only one child receiving NVP (p = 0.04). Conclusions: Despite poorer health at ART initiation, children treated for tuberculosis and receiving EFV-based regimens showed significant improvements comparable to children receiving NVP-based regimens. EFV-based regimens should be considered for young HIV-infected children co-infected with tuberculosis in resource-limited settings

Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport.

A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4\u27-diisothiocyanatostilbene-2,2\u27-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT

Parity and breast cancer risk among BRCA1 and BRCA2 mutation carriers.

INTRODUCTION: Increasing parity and age at first full-term pregnancy are established risk factors for breast cancer in the general population. However, their effects among BRCA1 and BRCA2 mutation carriers is still under debate. We used retrospective data on BRCA1 and BRCA2 mutation carriers from the UK to assess the effects of parity-related variables on breast cancer risk. METHODS: The data set included 457 mutation carriers who developed breast cancer (cases) and 332 healthy mutation carriers (controls), ascertained through families seen in genetic clinics. Hazard ratios were estimated by using a weighted cohort approach. RESULTS: Parous BRCA1 and BRCA2 mutation carriers were at a significantly lower risk of developing breast cancer (hazard ratio 0.54, 95% confidence interval 0.37 to 0.81; p = 0.002). The protective effect was observed only among carriers who were older than 40 years. Increasing age at first live birth was associated with an increased breast cancer risk among BRCA2 mutation carriers (p trend = 0.002) but not BRCA1 carriers. However, the analysis by age at first live birth was based on small numbers. CONCLUSION: The results suggest that the relative risks of breast cancer associated with parity among BRCA1 and BRCA2 mutation carriers may be similar to those in the general population and that reproductive history may be used to improve risk prediction in carriers.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are