816 research outputs found
N-Acryloylphenylalanine
The title compound, C12H13NO3, was prepared by the nucleophilic substitution reaction of acryloyl chloride with glycylglycine. In the crystal structure, intermolecular N—H⋯O, O–H⋯O and C—H⋯O hydrogen bonds link the molecules into a three-dimensional network
Intelligent diagnostic scheme for lung cancer screening with Raman spectra data by tensor network machine learning
Artificial intelligence (AI) has brought tremendous impacts on biomedical
sciences from academic researches to clinical applications, such as in
biomarkers' detection and diagnosis, optimization of treatment, and
identification of new therapeutic targets in drug discovery. However, the
contemporary AI technologies, particularly deep machine learning (ML), severely
suffer from non-interpretability, which might uncontrollably lead to incorrect
predictions. Interpretability is particularly crucial to ML for clinical
diagnosis as the consumers must gain necessary sense of security and trust from
firm grounds or convincing interpretations. In this work, we propose a
tensor-network (TN)-ML method to reliably predict lung cancer patients and
their stages via screening Raman spectra data of Volatile organic compounds
(VOCs) in exhaled breath, which are generally suitable as biomarkers and are
considered to be an ideal way for non-invasive lung cancer screening. The
prediction of TN-ML is based on the mutual distances of the breath samples
mapped to the quantum Hilbert space. Thanks to the quantum probabilistic
interpretation, the certainty of the predictions can be quantitatively
characterized. The accuracy of the samples with high certainty is almost
100. The incorrectly-classified samples exhibit obviously lower certainty,
and thus can be decipherably identified as anomalies, which will be handled by
human experts to guarantee high reliability. Our work sheds light on shifting
the ``AI for biomedical sciences'' from the conventional non-interpretable ML
schemes to the interpretable human-ML interactive approaches, for the purpose
of high accuracy and reliability.Comment: 10 pages, 7 figure
Seroprevalence and Risk Factors of Chlamydia abortus
Chlamydia abortus, an important pathogen in a variety of animals, is associated with abortion in sheep. In the present study, 1732 blood samples, collected from Tibetan sheep between June 2013 and April 2014, were examined by the indirect hemagglutination (IHA) test, aiming to evaluate the seroprevalence and risk factors of C. abortus infection in Tibetan sheep. 323 of 1732 (18.65%) samples were seropositive for C. abortus antibodies at the cut-off of 1 : 16. A multivariate logistic regression analysis was used to evaluate the risk factors associated with seroprevalence, which could provide foundation to prevent and control C. abortus infection in Tibetan sheep. Gender of Tibetan sheep was left out of the final model because it is not significant in the logistic regression analysis (P>0.05). Region, season, and age were considered as major risk factors associated with C. abortus infection in Tibetan sheep. Our study revealed a widespread and high prevalence of C. abortus infection in Tibetan sheep in Gansu province, northwest China, with higher exposure risk in different seasons and ages and distinct geographical distribution
Trogocytosis of MHC-I/Peptide Complexes Derived from Tumors and Infected Cells Enhances Dendritic Cell Cross-Priming and Promotes Adaptive T Cell Responses
The transporter associated with antigen processing (TAP) and the major histocompatibility complex class I (MHC-I), two important components of the MHC-I antigen presentation pathway, are often deficient in tumor cells. The restoration of their expression has been shown to restore the antigenicity and immunogenicity of tumor cells. However, it is unclear whether TAP and MHC-I expression in tumor cells can affect the induction phase of the T cell response. To address this issue, we expressed viral antigens in tumors that are either deficient or proficient in TAP and MHC-I expression. The relative efficiency of direct immunization or immunization through cross-presentation in promoting adaptive T cell responses was compared. The results demonstrated that stimulation of animals with TAP and MHC-I proficient tumor cells generated antigen specific T cells with greater killing activities than those of TAP and MHC-I deficient tumor cells. This discrepancy was traced to differences in the ability of dendritic cells (DCs) to access and sample different antigen reservoirs in TAP and MHC-I proficient versus deficient cells and thereby stimulate adaptive immune responses through the process of cross-presentation. In addition, our data suggest that the increased activity of T cells is caused by the enhanced DC uptake and utilization of MHC-I/peptide complexes from the proficient cells as an additional source of processed antigen. Furthermore, we demonstrate that immune-escape and metastasis are promoted in the absence of this DC ‘arming’ mechanism. Physiologically, this novel form of DC antigen sampling resembles trogocytosis, and acts to enhance T cell priming and increase the efficacy of adaptive immune responses against tumors and infectious pathogens
Inquiry web-based learning to enhance information problem solving competences in science
Early research on using web information indicates that secondary students fail to
explore much web tools, use them naively and have serious difficulties to
understand and integrate web information. In response to these challenges, the
main goal of this research has been to design, implement and evaluate an
instructional approach that helps students learn from web information. We have
developed on-line learning materials which focus on specific curricular contents
and provide specific scaffolds to help students accomplish web-based tasks and
develop specific information problem-solving competencies. These scaffolds have
intended to give support to students involved in information-seeking activities as
they were asked questions, searched for information, organised and assessed their
findings, and created rich representations of their newly-constructed
understandings. We have designed a one year long study to investigate the depth
and accuracy of 127 secondary students, as regards their content understanding as
well as their development of information problem-solving competencies when
using on-line resources to solve instructional tasks. Our research demonstrates that
the experimental group performed computer-based activities statistically better
than the control group. Our findings also suggest that students were able to
develop accurate and in-depth understanding from web information if they could
appropriately use search and managerial strategies. This research lends evidence
to questions regarding the value of students engaging in on-line inquiry web-based
learning to enhance content understanding and to develop more efficient
information problem-solving competencies in secondary education
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Transposon insertion causes cadherin mis-splicing and confers resistance to Bt cotton in pink bollworm from China
Transgenic crops producing insecticidal proteins from Bacillus thuringiensis (Bt) are cultivated extensively, but rapid evolution of resistance by pests reduces their efficacy. We report a 3,370-bp insertion in a cadherin gene associated with resistance to Bt toxin Cry1Ac in the pink bollworm (Pectinophora gossypiella), a devastating global cotton pest. We found the allele (r15) harboring this insertion in a field population from China. The insertion is a miniature inverted repeat transposable element (MITE) that contains two additional transposons and produces two mis-spliced transcript variants (r15A and r15B). A strain homozygous for r15 had 290-fold resistance to Cry1Ac, little or no cross-resistance to Cry2Ab, and completed its life cycle on Bt cotton producing Cry1Ac. Inheritance of resistance was recessive and tightly linked with r15. For transformed insect cells, susceptibility to Cry1Ac was greater for cells producing the wild-type cadherin than for cells producing the r15 mutant proteins. Recombinant cadherin protein occurred on the cell surface in cells transformed with the wildtype or r15A sequences, but not in cells transformed with the r15B sequence. The similar resistance of pink bollworm to Cry1Ac in laboratory-and field-selected insects from China, India and the U.S. provides a basis for developing international resistance management practices.China's Key Project for Breeding Genetically Modified Organisms [2016ZX08012-004]; Agriculture and Food Research Initiative Competitive Grant from the USDA National Institute of Food and Agriculture [2018-67013-27821]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Long-distance transport of sucrose in source leaves promotes sink root growth by the EIN3-SUC2 module
In most plants, sucrose, a major storage sugar, is transported into sink organs to support their growth. This key physiological process is dependent on the function of sucrose transporters. Sucrose export from source tissues is predominantly controlled through the activity of SUCROSE TRANSPORTER 2 (SUC2), required for the loading of sucrose into the phloem of Arabidopsis plants. However, how SUC2 activity is controlled to support root growth remains unclear. Glucose is perceived via the function of HEXOKINASE 1 (HXK1), the only known nuclear glucose sensor. HXK1 negatively regulates the stability of ETHYLENE-INSENSITIVE3 (EIN3), a key ethylene/glucose interaction component. Here we show that HXK1 functions upstream of EIN3 in the regulation of root sink growth mediated by glucose signaling. Furthermore, the transcription factor EIN3 directly inhibits SUC2 activity by binding to the SUC2 promoter, regulating glucose signaling linked to root sink growth. We demonstrate that these molecular components form a HXK1-EIN3-SUC2 module integral to the control of root sink growth. Also, we demonstrate that with increasing age, the HXK1-EIN3-SUC2 module promotes sucrose phloem loading in source tissues thereby elevating sucrose levels in sink roots. As a result, glucose signaling mediated-sink root growth is facilitated. Our findings thus establish a direct molecular link between the HXK1-EIN3-SUC2 module, the source-to sink transport of sucrose and root growth
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