3,994 research outputs found
Physical properties and behavior of high-performance concrete at high temperatures
The following report gives an overview of the TC program and some preliminary result
Effects of Solute-Solute Interactions on Protein Stability Studied Using Various Counterions and Dendrimers
Much work has been performed on understanding the effects of additives on protein thermodynamics and degradation kinetics, in particular addressing the Hofmeister series and other broad empirical phenomena. Little attention, however, has been paid to the effect of additive-additive interactions on proteins. Our group and others have recently shown that such interactions can actually govern protein events, such as aggregation. Here we use dendrimers, which have the advantage that both size and surface chemical groups can be changed and therein studied independently. Dendrimers are a relatively new and broad class of materials which have been demonstrated useful in biological and therapeutic applications, such as drug delivery, perturbing amyloid formation, etc. Guanidinium modified dendrimers pose an interesting case given that guanidinium can form multiple attractive hydrogen bonds with either a protein surface or other components in solution, such as hydrogen bond accepting counterions. Here we present a study which shows that the behavior of such macromolecule species (modified PAMAM dendrimers) is governed by intra-solvent interactions. Attractive guanidinium-anion interactions seem to cause clustering in solution, which inhibits cooperative binding to the protein surface but at the same time, significantly suppresses nonnative aggregation.Singapore-MIT Allianc
High Quality, Equity, and Assessment: An Analysis of Variables Impacting English Learner Standardized Science Test Performance and Implications for Construct Validity
In the United States, assessment is seen as a lever that can facilitate high-quality education. This study on English learners, students whose native language is not English, was based on data from eighth-grade English learners’ performance on science general and content-specific (physical, life, and earth science) standardized exams and an English language proficiency exam. The researchers utilized regression analysis to examine factors (i.e., socioeconomic status, home language, English language proficiency, and receptive and productive elements of language) that are predictive of English learner performance in general and content-specific science standardized assessments to identify implications for construct validity of high-stakes science assessments. The research question is as follows: What factors influence the performance of English learners on a standardized science assessment, including overall performance and content-specific domains? Three main findings emerged from this research study. First, this study confirms previous research indicating that socioeconomic status and English language proficiency are predictive of English learners’ achievement on content-based standardized tests. Second, this study adds to current research by providing evidence that productive language scores are the most significant predictors of English learner science achievement, in comparison to receptive language scores, overall English language proficiency scores, home language, and socioeconomic status. Third, this study adds to the body of evidence needed to challenge the validity of standardized science tests for English learner populations. The findings of this study challenge the construct validity of science content-based assessments for English learners, emphasizing the importance of productive language in academic performance
Microlensing modulation by quadrupole variation
We investigate microlensing in the case where the lens is considered as an
extended object. We use a multipolar expansion of the lens potential and show
that the time-varying nature of the quadrupole contribution allows to separate
it from the mass and spin contributions and leads to specific modulations of
the amplification signal. As example we study the case of binary system lenses
in our galaxy. The modulation is observable if the rotation period of the
system is smaller than the time over which the amplification is significant and
if the impact parameter of the passing light ray is sufficiently close to the
Einstein radius so that the amplification is large. Observations of this
modulation can reveal important information on the quadrupole and thus on the
gravitational radiation emitted by the binary lens. Even if not observed
directly, because of their importance the quadrupole modulation has to be
included in the error budget for high magnification () microlensing
events.Comment: Matches publicated versio
Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy
The open cluster NGC 6791 is among the oldest, most massive and metal-rich
open clusters in the Galaxy. High-resolution -band spectra from the Apache
Point Observatory Galactic Evolution Experiment (APOGEE) of 11 red giants in
NGC 6791 are analyzed for their chemical abundances of iron, oxygen, and
sodium. The abundances of these three elements are found to be homogeneous
(with abundance dispersions at the level of 0.05 - 0.07 dex) in these
cluster red giants, which span much of the red-giant branch (T
3500K - 4600K), and include two red-clump giants. From the infrared
spectra, this cluster is confirmed to be among the most metal-rich clusters in
the Galaxy ( = 0.34 0.06), and is found to have a roughly
solar value of [O/Fe] and slightly enhanced [Na/Fe]. Non-LTE calculations for
the studied Na I lines in the APOGEE spectral region (16373.86\AA\ and
16388.85\AA) indicate only small departures from LTE ( 0.04 dex)
for the parameter range and metallicity of the studied stars. The previously
reported double population of cluster members with different Na abundances is
not found among the studied sample.Comment: Accepted for publication at ApJ Letter
Inter-cultural differences in response to a computer-based anti-bullying intervention
Background and purpose: Many holistic anti-bullying interventions have been attempted, with mixed success, while little work has been done to promote a 'self-help' approach to victimisation. The rise of the ICT curriculum and computer support in schools now allows for approaches that benefit from technology to be implemented. This study evaluates the cross-cultural effects of a computer-based anti-bullying intervention on primary school-aged children's knowledge about bullying and relevant coping strategies.
Programme description: FearNot! is an interactive computer-based virtual learning environment designed for use as an anti-bullying intervention. It includes interactive virtual agents who assume the most common participant roles found in episodes of bullying. FearNot! was used by children over three consecutive weeks to allow its effectiveness to be evaluated in a longitudinal in situ programme.
Sample: Two comparable samples were drawn from the UK and Germany. In the UK, 651 participants (aged 8-11) were recruited from primary schools in Hertfordshire, Coventry and Warwickshire, whereas the 535 German participants (aged 7-10) were sourced from Grundschulen in the Bayern and Hessen regions. Because of lack of parental consent, late joiners and absences/missing responses, data from 908 participants (UK 493; Germany 415) were analysed.
Design and methods: A quasi-experimental, pre/post-tests control group design employed pre-published and bespoke questionnaires to collect data. Descriptive and inferential analyses were conducted.
Results: UK students possessed higher coping strategy knowledge scores than German participants, but German children's scores improved over time and as a result of the FearNot! intervention.
Conclusions: Overall, while not effective at increasing children's coping strategy knowledge in this study, the FearNot! intervention could prove a useful classroom tool to approach the issue of bullying as part of a wider initiative. Cultural differences at baseline and reactions to the intervention are discussed
Targeting FLT3 in primary MLL-gene-rearranged infant acute lymphoblastic leukemia
Acute lymphoblastic leukemia (ALL) in infants is characterized by
rearrangements of the mixed lineage leukemia (MLL) gene, drug resistance,
and a poor treatment outcome. Therefore, novel therapeutic strategies are
needed to improve prognosis. Recently, we showed that FLT3 is highly
expressed in MLL rearranged ALL (MLL). Here we demonstrate FLT3 expression
in infants with MLL (n = 41) to be significantly higher compared to both
infant (n = 8; P < .001) and noninfant patients with ALL (n = 23; P =
.001) carrying germline MLL genes. Furthermore, leukemic cells from
infants with MLL were significantly more sensitive to the Fms-like
tyrosine kinase 3 (FLT3) inhibitor PKC412 (N-benzoyl staurosporine) than
noninfant ALL cells, and at least as sensitive as internal tandem
duplication-positive (ITD+) AML cells. Surprisingly, activation loop
mutations only occurred in about 3% (1 of 36) of the cases and no
FLT3/ITDs were observed. However, measuring FLT3 phosphorylation in
infants with MLL expressing varying levels of wild-type FLT3 revealed that
high-level FLT3 expression is associated with ligand-independent FLT3
activation. This suggests that infant MLL cells displaying activated FLT3
as a result of overexpression can be targeted by FLT3 inhibitors such as
PKC412. However, at concentrations of PKC412 minimall
Long-term follow-up of cytogenetically normal CEBPA-mutated AML
Background: The aim of this study was to analyze the long-term survival of AML patients with CEBPA mutations. Patients and methods: We investigated 88 AML patients with a median age of 61 years and (1) cytogenetically normal AML (CN-AML), (2) monoallelic (moCEBPA) or biallelic (biCEBPA) CEBPA mutation, and (3) intensive induction treatment. 60/88 patients have been described previously with a shorter follow-up. Results: Median follow-up time was 9.8 years (95% CI: 9.4-10.1 years) compared to 3.2 and 5.2 years in our former analyses. Patients with biCEBPA mutations survived significantly longer compared to those with moCEBPA (median overall survival (OS) 9.6 years vs. 1.7 years, p = 0.008). Patients <= 60 years and biCEBPA mutations showed a favorable prognosis with a 10-year OS rate of 81%. Both, bi- and moCEBPA-mutated groups had a low early death (d60) rate of 7% and 9%, respectively. Complete remission (CR) rates for biCEBPA and moCEBPA mutated patients were 82% vs. 70% (p = 0.17). biCEBPA mutated patients showed a longer relapse free survival (RFS) (median RFS 9.4 years vs. 1.5 years, p = 0.021) and a lower cumulative incidence of relapse (CIR) compared to moCEBPA-mutated patients. These differences in OS and RFS were confirmed after adjustment for known clinical and molecular prognostic factors. Conclusions: In this long-term observation we confirmed the favorable prognostic outcome of patients with biCEBPA mutations compared to moCEBPA-mutated CN-AML. The high probability of OS (81%) in younger patients is helpful to guide intensity of postremission therapy
Over-the-scope clip (OTSC (R)) closure of a recto-acetabular fistula
A 25-year-old male Syrian refugee presented in our hospital with recurrent hip infections after having undergone hip arthroplasty abroad following destruction of his right hip joint by shell splinters in the Syrian civil war. The patient underwent hip arthroplasty revision with implantation of a cement spacer. CT-scan with rectal contrast media filling revealed a rectoacetabular fistula. Consecutively, the patient underwent ileostomy formation. The fistula was then successfully closed by endoscopic over-the-scope clipping (OTSC (R)). Fistulas between intestines and joints rarely develop and in the few cases published mostly extensive abdominal rescue surgery has been performed. Here, we present a case of a traumatic rectoacetabular fistula that was successfully closed by OTSC. This innovative method could represent a safe and suitable option to effectively close fistulas between joints and intestines thereby avoiding extensive rescue surgery with bowel resection or permanent ostomy
Importance of animal/human health interface
This study analyzed the importance of zoonoses and communicable diseases common to man and animals as potential Public Health Emergencies of Internationa
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