427 research outputs found
Learning a local-variable model of aromatic and conjugated systems
A collection of new
approaches to building and training neural
networks, collectively referred to as deep learning, are attracting
attention in theoretical chemistry. Several groups aim to replace
computationally expensive <i>ab initio</i> quantum mechanics
calculations with learned estimators. This raises questions about
the representability of complex quantum chemical systems with neural
networks. Can local-variable models efficiently approximate nonlocal
quantum chemical features? Here, we find that convolutional architectures,
those that only aggregate information locally, cannot efficiently
represent aromaticity and conjugation in large systems. They cannot
represent long-range nonlocality known to be important in quantum
chemistry. This study uses aromatic and conjugated systems computed
from molecule graphs, though reproducing quantum simulations is the
ultimate goal. This task, by definition, is both computable and known
to be important to chemistry. The failure of convolutional architectures
on this focused task calls into question their use in modeling quantum
mechanics. To remedy this heretofore unrecognized deficiency, we introduce
a new architecture that propagates information back and forth in waves
of nonlinear computation. This architecture is still a local-variable
model, and it is both computationally and representationally efficient,
processing molecules in sublinear time with far fewer parameters than
convolutional networks. Wave-like propagation models aromatic and
conjugated systems with high accuracy, and even models the impact
of small structural changes on large molecules. This new architecture
demonstrates that some nonlocal features of quantum chemistry can
be efficiently represented in local variable models
Modeling reactivity to biological macromolecules with a deep multitask network
Most
small-molecule drug candidates fail before entering the market,
frequently because of unexpected toxicity. Often, toxicity is detected
only late in drug development, because many types of toxicities, especially
idiosyncratic adverse drug reactions (IADRs), are particularly hard
to predict and detect. Moreover, drug-induced liver injury (DILI)
is the most frequent reason drugs are withdrawn from the market and
causes 50% of acute liver failure cases in the United States. A common
mechanism often underlies many types of drug toxicities, including
both DILI and IADRs. Drugs are bioactivated by drug-metabolizing enzymes
into reactive metabolites, which then conjugate to sites in proteins
or DNA to form adducts. DNA adducts are often mutagenic and may alter
the reading and copying of genes and their regulatory elements, causing
gene dysregulation and even triggering cancer. Similarly, protein
adducts can disrupt their normal biological functions and induce harmful
immune responses. Unfortunately, reactive metabolites are not reliably
detected by experiments, and it is also expensive to test drug candidates
for potential to form DNA or protein adducts during the early stages
of drug development. In contrast, computational methods have the potential
to quickly screen for covalent binding potential, thereby flagging
problematic molecules and reducing the total number of necessary experiments.
Here, we train a deep convolution neural networkî—¸the XenoSite
reactivity modelî—¸using literature data to accurately predict
both sites and probability of reactivity for molecules with glutathione,
cyanide, protein, and DNA. On the site level, cross-validated predictions
had area under the curve (AUC) performances of 89.8% for DNA and 94.4%
for protein. Furthermore, the model separated molecules electrophilically
reactive with DNA and protein from nonreactive molecules with cross-validated
AUC performances of 78.7% and 79.8%, respectively. On both the site-
and molecule-level, the model’s performances significantly
outperformed reactivity indices derived from quantum simulations that
are reported in the literature. Moreover, we developed and applied
a selectivity score to assess preferential reactions with the macromolecules
as opposed to the common screening traps. For the entire data set
of 2803 molecules, this approach yielded totals of 257 (9.2%) and
227 (8.1%) molecules predicted to be reactive only with DNA and protein,
respectively, and hence those that would be missed by standard reactivity
screening experiments. Site of reactivity data is an underutilized
resource that can be used to not only predict if molecules are reactive,
but also show where they might be modified to reduce toxicity while
retaining efficacy. The XenoSite reactivity model is available at http://swami.wustl.edu/xenosite/p/reactivity
The influence of instructional materials on mathematics achievement of senior secondary students in Akamkpa Local Government Area of Cross River State, Nigeria
Having observed the reckless abandonment of professional codes and ethics of teaching soon after certification, and specifically the subterfuge of the use of instructional materials in lesson delivery, the researchers set out to investigate the state-of-the-art in terms of availability and use of mathematical instructional materials, and the influence of these on students’ achievement in the subject. Three instruments, a 20-item Mathematics Teacher Instructional Materials Availability Questionnaire (TIMAQ), a 20-item Mathematics Teacher Instructional Material Use Questionnaire (TIMUQ) and a 30-item Multiple Choice Achievement Test (MCAT) were developed, validated (test-retest reliability coefficients of 0.87 and 0.97 respectively for TIMAQ and TIMUQ, and KR-20 coefficient of 0.89 with mean 40.8, S.D. 11.33) for MCAT. Two hundred (200) students (20 per school comprising 100 male and 100 female) were selected from the ten public secondary schools in Akamkpa Local Government Area by stratified random technique, and two (2) Mathematics teachers per school for the study. Results of the simple percentage and independent t-test analyses revealed the non-availability and non use of instructional materials in Mathematics instruction, as well as significant achievement differences between materials-available and non-available schools on one hand and achievement of students from material-used and non–used schools on the other. Useful recommendations were therefore made based on these findings.Keywords: mathematics instructional materials, students’ achievement, availability of instructional materials, use of instructional material
Impact of Aspirin Supplementation for Pre-Eclampsia Prevention on Neonatal Outcomes
Introduction. Preeclampsia affects approximately 4.6% of pregnancies worldwide. In 2018, ACOG updated their low dose aspirin (LDA) supplementation recommendation to include pregnant women at moderate risk for preeclampsia. In addition to the potential benefit of LDA supplementation for delaying or preventing preeclampsia, LDA supplementation can affect neonatal outcomes. We study the association of LDA supplementation with six neonatal outcomes: length of stay (LOS) in hospital, NICU admission, hospital readmission, birth weight (BW), one-minute Apgar score, and five-minute Apgar score in a sample of mostly minority pregnant women from Hispanic and Black race/ethnicities.
Methods. This was a retrospective study of 634 patients from January 2018 through April 2021.Our main predictor variable was maternal LDA supplementation on 6 neonatal outcomes: NICU admission, neonatal readmission, one and five minute Apgar scores, neonatal BW and hospital LOS. We adjusted for demographics, comorbidities and maternal high- or moderate-risk designation per ACOG guidelines.
Results. We found that high-risk designation was associated with neonatal increased rate of NICU admission (OR: 3.80, 95% CI: 2.02, 7.13, p<0.001), LOS (B=0.15, SE=0.04, p<0.001) and decreased birthweight (B=-442.10, SE=75.07, p <0.001). We found no significant association with LDA supplementation and NICU admission, readmission, low one and five minute Apgar scores, BW and LOS.
Conclusions. We did not find any association of LDA supplementation with NICU admission, hospital readmission, low one-minute or five-minute Apgar score, birthweight, and LOS. Clinicians recommending maternal LDA supplementation should be aware that LDA supplementation does not appear to provide any benefits for these neonatal outcomes
Impact of Aspirin Supplementation for Pre-Eclampsia Prevention on Neonatal Outcomes
Introduction. Preeclampsia affects approximately 4.6% of pregnancies worldwide. In 2018, ACOG updated their low dose aspirin (LDA) supplementation recommendation to include pregnant women at moderate risk for preeclampsia. In addition to the potential benefit of LDA supplementation for delaying or preventing preeclampsia, LDA supplementation can affect neonatal outcomes. We study the association of LDA supplementation with six neonatal outcomes: length of stay (LOS) in hospital, NICU admission, hospital readmission, birth weight (BW), one-minute Apgar score, and five-minute Apgar score in a sample of mostly minority pregnant women from Hispanic and Black race/ethnicities.
Methods. This was a retrospective study of 634 patients from January 2018 through April 2021.Our main predictor variable was maternal LDA supplementation on 6 neonatal outcomes: NICU admission, neonatal readmission, one and five minute Apgar scores, neonatal BW and hospital LOS. We adjusted for demographics, comorbidities and maternal high- or moderate-risk designation per ACOG guidelines.
Results. We found that high-risk designation was associated with neonatal increased rate of NICU admission (OR: 3.80, 95% CI: 2.02, 7.13, p<0.001), LOS (B=0.15, SE=0.04, p<0.001) and decreased birthweight (B=-442.10, SE=75.07, p <0.001). We found no significant association with LDA supplementation and NICU admission, readmission, low one and five minute Apgar scores, BW and LOS.
Conclusions. We did not find any association of LDA supplementation with NICU admission, hospital readmission, low one-minute or five-minute Apgar score, birthweight, and LOS. Clinicians recommending maternal LDA supplementation should be aware that LDA supplementation does not appear to provide any benefits for these neonatal outcomes
mHealth in China and the United States: How Mobile Technology is Transforming Healthcare in the World's Two Largest Economies
In this paper, we explore ways mobile technology can help with these difficulties. Specifically, we look at avenues through which mobile devices boost productivity, aid communications, and help providers improve affordability, access, and treatment. Using data drawn from China and the United States as well as global trends, we look at recent developments andemerging opportunities in mobile health, or mHealth. We argue that mobile technology assists patients, health providers, and policymakers in several different respects. It helps patients by giving them tools to monitor their health conditions and communicate those results to physicians. It enables health providers to connect with colleagues and offers alternative sources of information for patients. It is also an important tool to inform policymakers on health delivery and medical outcomes
Growing Season Air mass Equivalent Temperature (T\u3csub\u3eE\u3c/sub\u3e) in the East Central USA
Equivalent temperature (TE), which incorporates both dry (surface air temperature, T) and moist heat content associated with atmospheric moisture, is a better indicator of overall atmospheric heat content compared to T alone. This paper investigates the impacts of different types of air masses on TE during the growing season (April–September). The study used data from the Kentucky Mesonet for this purpose. The growing season was divided into early (April–May), mid (June–July), and late (August–September). Analysis suggests that TE for moist tropical (MT) air mass was as high as 61 and 81 °C for the early and mid-growing season, respectively. Further analysis suggests that TE for different parts of the growing seasons were statistically significantly different from each other. In addition, TE for different air masses was also statistically significantly different from each other. The difference between TE and T (i.e. TE-T) is smaller under dry atmospheric conditions but larger under moist conditions. For example, in Barren County, the lowest difference (20–10 °C) was 10 °C. It was reported on 18 April 2010, a dry weather day. On the other hand, the highest difference for this site was 48 °C and was reported on 11 August 2010, a humid day
Growing Season Air mass Equivalent Temperature (TE) in the East Central USA
Equivalent temperature (TE), which incorporates both dry (surface air temperature, T) and moist heat content associated with atmospheric moisture, is a better indicator of overall atmospheric heat content compared to T alone. This paper investigates the impacts of different types of air masses on TE during the growing season (April–September). The study used data from the Kentucky Mesonet for this purpose. The growing season was divided into early (April–May), mid (June–July), and late (August–September). Analysis suggests that TE for moist tropical (MT) air mass was as high as 61 and 81 C for the early and mid-growing season, respectively. Further analysis suggests that TE for different parts of the growing seasons were statistically significantly different from each other. In addition, TE for different air masses was also statistically significantly different from each other. The v between TE and T (i.e. TE-T) is smaller under dry atmospheric conditions but larger under moist conditions. For example, in Barren County, the lowest difference (20–10 C) was 10 C. It was reported on 18 April 2010, a dry weather day. On the other hand, the highest difference for this site was 48 C and was reported on 11 August 2010, a humid day
Inhibitory projections from the ventral nucleus of the lateral lemniscus and superior paraolivary nucleus create directional selectivity of frequency modulations in the inferior colliculus: A comparison of bats with other mammals
This review considers four auditory brainstem nuclear groups and shows how studies of both bats and other mammals have provided insights into their response properties and the impact of their convergence in the inferior colliculus (IC). The four groups are octopus cells in the cochlear nucleus, their connections with the ventral nucleus of the lateral lemniscus (VNLL) and the superior paraolivary nucleus (SPON), and the connections of the VNLL and SPON with the IC. The theme is that the response properties of neurons in the SPON and VNLL map closely onto the synaptic response features of a unique subpopulation of cells in the IC of bats whose inputs are dominated by inhibition. We propose that the convergence of VNLL and SPON inputs generates the tuning of these IC cells, their unique temporal responses to tones, and their directional selectivities for frequency modulated (FM) sweeps. Other IC neurons form directional properties in other ways, showing that selective response properties are formed in multiple ways. In the final section we discuss why multiple formations of common response properties could amplify differences in population activity patterns evoked by signals that have similar spectrotemporal features
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