Back-pressure Effect on Shock-Train Location in a Scramjet Engine Isolator

The isolator of the scramjet decelerates the incoming high Mach flow to a lower Mach number and stabilizes the flow before it enters the combustor. Because of the unsteady combustion phenomenon and inconsistent completeness of the combustion, pressures within the combustor can vary drastically. These pressure variations can propagate forward and affect the flow field in the isolator - worst case unstarting the inlet. In this research, the shock train location versus the back-pressure is examined experimentally. The back-pressure is artificially created by symmetric (top & bottom) ramps that can close the flow area. Raising/lowering ramps result in higher/lower back-pressure. Higher back-pressure moves the shock train forward, with too high a back-pressure causing un-start. This experiment is conducted for a variation in Reynolds number, ramp angle, and two incoming Mach #s, and will result in a relationship between back-pressure and shock train location for various airflow conditions

Intra-uterine fetal demise caused by amniotic band syndrome after standard amniocentesis

The amniotic band syndrome represents a prime example of exogenous disruption of an otherwise normal feta I development. It may be a sequel of invasive diagnostic procedures such as amniocentesis or fetal blood sampling. A 38-year-old gravida II, para II delivered a morphologically normal male stillborn at term. The pregnancy history had been unremarkable but for an early 2nd-trimester amniocentesis. Cause of the intra-uterine fetal demise was noted to be an amniotic band constricting the umbilical cord, An amniotic band is a rare but potentially fatal condition which may be induced by, e.g., invasive prenatal procedures. Such bands are not usually diagnosed prenatally; however, selected patients with augmented risk may profit from intensive ultrasound evaluation including Doppler studies. Copyright (C) 2000 S. Karger AG, Basel

Antifungal Prophylaxis and Risk for Invasive Mold Infections in Children with Hematologic Malignancies

Introduction: Invasive mold infections (IMI) are a leading cause of mortality in immunocompromised hosts. Children diagnosed with hematologic malignancies experience profound, prolonged neutropenia following intensive chemotherapy, and are at increased risk for infection-related outcomes. Depending on the anticipated therapeutic intensity, antimicrobial prophylaxis may be employed to mitigate risk for infection. We conducted a retrospective review of children diagnosed with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), or lymphoma between 2006-2015 and determined the incidence of IMI to be 4.8% (47/976), with an exceptionally high incidence observed in patients with AML (8.1%). This observation prompted a change in clinical practice that broadened prophylaxis for high risk patients to include coverage of molds, and resulted in development of a risk-stratified algorithm for antifungal prophylaxis in children with hematologic malignancies. The objective of this study was to evaluate the change in IMI incidence post-implementation of this algorithm, and to identify host factors contributing to risk for IMI in children with hematologic malignancies. Objective: The objective was to compare the incidence of IMI pre/post implementation of antifungal prophylaxis decision tree. Also, it was planned to evaluate the impact of race/ethnicity on the development of IMI in children with hematologic malignancies. Methods: We conducted a retrospective review of children ≤ 21 years old and diagnosed with ALL, AML, or lymphoma between 2016-2019, and were treated for IMI between 2016 and June 2020. To identify potential cases, we employed a strategy identical to the one used in the 2006-2015 review, specifically, a search of the electronic medical record utilizing ICD9 codes broadly inclusive of relevant cancer and fungal diagnoses. Each potentially eligible case was then reviewed for the following inclusion/exclusion criteria (also identical to the prior review): diagnosis and treatment of ALL, AML, or lymphoma at Texas Children’s Hospital, diagnosis of IMI that met criteria for ‘proven’ or ‘probable’ per the European Organization for Research and Treatment of Cancer/Mycoses Study Group and occurring prior to stem cell transplant, and no underlying immunodeficiency or history of solid organ transplant. Host and disease-related factors, as well as IMI incidence, were compared for 2006-2015 vs. 2016-2020 using a Chi-square, Fisher, or Student t-test as appropriate, and host factors predictive of IMI were assessed by multivariable linear regression. Results: The overall incidence of proven/probable IMI in children diagnosed with hematological malignancies between 2006-2019 was 4.2% (61/1456). The incidence of IMI decreased from 4.8% to 2.9% between 2006-2015 and 2016-2020. For specific diagnoses, the rate of IMI decreased from 5.0% to 3.6% (ALL, 35/705 vs. 10/276), from 1.9% to 1.4% (lymphoma, 47/976 vs. 14/480), and from 8.1% to 3.2% (AML, 9/111 vs. 2/62). No significant differences in host factor or disease-related characteristics were noted when comparing IMI cases in 2006-2015 vs. 2016-2020, nor were there differences in the proportion of patients in relapse at the time of IMI or taking antifungal prophylaxis. Substantial differences in representative mold species were noted between the two-time periods, e.g. Aspergillus spp. accounted for 19/47 IMI from 2006-2015, but accounted for none of the IMIs diagnosed 2016-2020. In 2016-2020, 5/14 IMI were due to Trichosporon spp., with 4/14 Rhizopus spp., 2/14 Fusarium spp., 1/14 Curvularia spp., 1/14 Histoplasma spp., and 1 that met criteria for probable IMI. In multivariable analyses (Table 1), Hispanics were more likely to develop an IMI than non-Hispanics (p=0.04, OR 1.94, CI 1.03-3.66), and those with lymphoma were less likely to develop an IMI than those with ALL (p=0.03, OR 0.33, CI 0.12-0.87). Patients diagnosed between 2016- 2019 were substantially less likely to develop IMI than those diagnosed 2006-2015 (p=0.003, OR 0.33, CI 0.16-0.69). Discussion and Conclusion: In this single institution study, risk for IMI in children with hematologic malignancies declined significantly after implementation of an antifungal prophylaxis algorithm that broadened coverage for high risk populations. Hispanics were at higher risk for IMI than non-Hispanics, suggesting a need to investigate relevant factors contributing to this disparity. This project can be used to further investigate the factors that contributed to invasive mold infections using a larger study populations. We can then continue to explore the potential contributing factors to the racial and ethnic disparities by including potential contributing factors such as socioeconomic factors and genetic risk

Evaluating implicit feedback models using searcher simulations

In this article we describe an evaluation of relevance feedback (RF) algorithms using searcher simulations. Since these algorithms select additional terms for query modification based on inferences made from searcher interaction, not on relevance information searchers explicitly provide (as in traditional RF), we refer to them as implicit feedback models. We introduce six different models that base their decisions on the interactions of searchers and use different approaches to rank query modification terms. The aim of this article is to determine which of these models should be used to assist searchers in the systems we develop. To evaluate these models we used searcher simulations that afforded us more control over the experimental conditions than experiments with human subjects and allowed complex interaction to be modeled without the need for costly human experimentation. The simulation-based evaluation methodology measures how well the models learn the distribution of terms across relevant documents (i.e., learn what information is relevant) and how well they improve search effectiveness (i.e., create effective search queries). Our findings show that an implicit feedback model based on Jeffrey's rule of conditioning outperformed other models under investigation

Effect of the GaAsP shell on optical properties of self-catalyzed GaAs nanowires grown on silicon

We realize growth of self-catalyzed core-shell GaAs/GaAsP nanowires (NWs) on Si substrates using molecular-beam epitaxy. Transmission electron microscopy (TEM) of single GaAs/GaAsP NWs confirms their high crystal quality and shows domination of the zinc-blende phase. This is further confirmed in optics of single NWs, studied using cw and time-resolved photoluminescence (PL). A detailed comparison with uncapped GaAs NWs emphasizes the effect of the GaAsP capping in suppressing the non-radiative surface states: significant PL enhancement in the core-shell structures exceeding 2000 times at 10K is observed; in uncapped NWs PL is quenched at 60K whereas single core-shell GaAs/GaAsP NWs exhibit bright emission even at room temperature. From analysis of the PL temperature dependence in both types of NW we are able to determine the main carrier escape mechanisms leading to the PL quench

Translation initiation mediated by RNA looping

Eukaryotic translation initiation commences at the initiation codon near the 5' end of mRNA by a 40S ribosomal subunit, and the recruitment of a 40S ribosome to an mRNA is facilitated by translation initiation factors interacting with the m7G cap and/or poly (A) tail. The 40S ribosome recruited to an mRNA is then transferred to the AUG initiation codon with the help of translation initiation factors. To understand the mechanism by which the ribosome finds an initiation codon, we investigated the role of eIF4G in finding the translational initiation codon. An artificial polypeptide eIF4G fused with MS2 was localized downstream of the reporter gene through MS2-binding sites inserted in the 3' UTR of the mRNA. Translation of the reporter was greatly enhanced by the eIF4G-MS2 fusion protein regardless of the presence of a cap structure. Moreover, eIF4G-MS2 tethered at the 3' UTR enhanced translation of the second cistron of a dicistronic mRNA. The encephalomyocarditis virus internal ribosome entry site, a natural translational-enhancing element facilitating translation through an interaction with eIF4G, positioned downstream of a reporter gene, also enhanced translation of the upstream gene in a cap-independent manner. Finally, we mathematically modeled the effect of distance between the cap structure and initiation codon on the translation efficiency of mRNAs. The most plausible explanation for translational enhancement by the translational-enhancing sites is recognition of the initiation codon by the ribosome bound to the ribosome-recruiting sites through "RNA looping." The RNA looping hypothesis provides a logical explanation for augmentation of translation by enhancing elements located upstream and/or downstream of a protein-coding region.open112122sciescopu

Evaluating the feasibility of administering a combination of online dietary assessment tools in a cohort of adults in Alberta, Canada

Purpose: Evidence suggests that combining tools, such as 24-hour recalls and food frequency questionnaires, may allow more accurate assessment of diet in epidemiologic studies. Webbased technology should make this approach more feasible than in the past, but it is important to explore response rates and acceptability of such an approach in real-world settings. We sought to determine the feasibility of using a combination of online tools (Automated SelfAdministered 24-hour (ASA24) Dietary Assessment Tool and Diet History Questionnaire-II (DHQ-II)) in a sub-set of participants in Alberta’s Tomorrow Project (ATP); a prospective cohort of 55,000 adults >35y in Alberta, Canada. Methods: Invitations to the feasibility study were mailed to 550 ATP participants. Those who consented (n=331) were asked to complete a health questionnaire, four ASA24 recalls (approximately three weeks apart over a four month period, with staggered start dates between June and December 2016), followed by the DHQ-II, and an evaluation survey. Results: The majority of participants [mean (SD) age =57.1 (10.1)] were women (70.7%), urban residents (84.8%) and non-smokers (95.7%). Of the 229 participants who completed at least one ASA24, roughly equal proportions completed one (24.8%), two (24.5%), three (24.5%) and four recalls (26.2%). One third (n=102) of consenting participants did not respond to any ASA24 recall requests, with “lack of time” given as the primary reason. Only 41% of consenting participants (n=136) completed the DHQ-II; of these, 40% (n=55) completed all four recalls. Median (25th-75th percentile) completion times were 46 (26-64) minutes for the first ASA24 recall and 50 (40-90) minutes for the DHQ-II. Conclusions: Over half of participants completed at least two or more ASA24 recalls, and those who completed a greater number of recalls also completed the DHQ-II, demonstrating that the approach is feasible in the ATP cohort. However, response rates may be sensitive to the timing and frequency of recall administration. Future investigations will (i) evaluate the dietary data collected from each tool; (ii) explore methods of combining the data to optimize assessment of diet in the cohort, while accounting for the fact that not all participants will complete the entire dietary assessment protocol

ASCOT: a text mining-based web-service for efficient search and assisted creation of clinical trials

Clinical trials are mandatory protocols describing medical research on humans and among the most valuable sources of medical practice evidence. Searching for trials relevant to some query is laborious due to the immense number of existing protocols. Apart from search, writing new trials includes composing detailed eligibility criteria, which might be time-consuming, especially for new researchers. In this paper we present ASCOT, an efficient search application customised for clinical trials. ASCOT uses text mining and data mining methods to enrich clinical trials with metadata, that in turn serve as effective tools to narrow down search. In addition, ASCOT integrates a component for recommending eligibility criteria based on a set of selected protocols

Development and Evaluation of Two Simple, Rapid Immunochromatographic Tests for the Detection of Yersinia pestis Antibodies in Humans and Reservoirs

Plague is due to the bacterium Yersinia pestis. It is accidentally transmitted to humans by the bite of infected fleas. Currently, approximately 20 developing countries with very limited infrastructure are still affected. A plague case was defined according to clinical, epidemiological and biological features. Rapid diagnosis and surveillance of the disease are essential for its control. Indeed, the delay of treatment is often rapidly fatal for patients and outbreaks may occur. Bubo aspirate is the most appropriate specimen in case of bubonic plague, but its collection is not always feasible. The main current biological approaches for the diagnosis of human plague are F1 antigen detection, serology for antibody detection by ELISA and Y. pestis isolation. The biological diagnosis of plague remains a challenge because the clinical signs are not specific. In this study, we developed some simple, rapid and affordable tests able to detect specific plague antibodies. These tests can be used as alternative methods for plague diagnosis in the field and for plague surveillance