318 research outputs found
DxFormer: A Decoupled Automatic Diagnostic System Based on Decoder-Encoder Transformer with Dense Symptom Representations
Diagnosis-oriented dialogue system queries the patient's health condition and
makes predictions about possible diseases through continuous interaction with
the patient. A few studies use reinforcement learning (RL) to learn the optimal
policy from the joint action space of symptoms and diseases. However, existing
RL (or Non-RL) methods cannot achieve sufficiently good prediction accuracy,
still far from its upper limit. To address the problem, we propose a decoupled
automatic diagnostic framework DxFormer, which divides the diagnosis process
into two steps: symptom inquiry and disease diagnosis, where the transition
from symptom inquiry to disease diagnosis is explicitly determined by the
stopping criteria. In DxFormer, we treat each symptom as a token, and formalize
the symptom inquiry and disease diagnosis to a language generation model and a
sequence classification model respectively. We use the inverted version of
Transformer, i.e., the decoder-encoder structure, to learn the representation
of symptoms by jointly optimizing the reinforce reward and cross entropy loss.
Extensive experiments on three public real-world datasets prove that our
proposed model can effectively learn doctors' clinical experience and achieve
the state-of-the-art results in terms of symptom recall and diagnostic
accuracy.Comment: 7 pages, 4 figures, 3 table
Translational Control Mechanisms Analyzed in Neurospora crassa
The Neurospora crassa arg-2 gene encodes the small subunit of carbamoyl phosphate synthetase, the first enzyme in fungal arginine (Arg) biosynthesis. The arginine attenuator peptide (AAP), specified by an upstream open reading frame (uORF), stalls ribosomes at its termination codon in response Arg to control the translation of arg-2. In project 1, the effect of AAP and Arg on ribosome peptidyl transferase center (PTC) activity was analyzed in N. crassa and wheat germ cell-free translation extracts using the transfer of nascent AAP to puromycin as an assay. The results show that inhibition of PTC activity by the AAP and Arg is the basis for the AAP’s function. The mode of PTC inhibition appears unusual because neither a specific amino acid nor a specific nascent peptide chain length was required for AAP to function.
In eukaryotic translation initiation, the stringency of start codon selection impacts initiation efficiencies at AUG codons in different contexts and at near-cognate codons (NCCs) that differ from AUG by a single nucleotide. In project 2, a codon-optimized firefly luciferase reporter was used to examine the stringency of start codon selection in N. crassa. In vivo and in vitro results indicated that the hierarchy of initiation in N. crassa is similar to that in human cells. The preferred context was more important for efficient initiation from NCCs than from AUG.
In project 3, the use of NCCs was also specifically examined for the N. crassa cpc-1 gene. cpc-1 and Saccharomyces cerevisiae GCN4 are homologs specifying a transcription activator, which drives the primary transcriptional response to amino acid starvation. In vitro studies showed that uORF1 and uORF2 in cpc-1 are functionally analogous to uORF1 and uORF4 in GCN4. uORF1 promotes reinitiation at downstream start codons. uORF2 inhibits translation from the main cpc-1 start codon. Four NCCs in the CPC1 reading frame and upstream of uORF2 can also be used for translation initiation.
In summary, we explored uORF-mediated translational regulation and the use of NCCs as initiation codons. Taken together, these studies establish N. crassa as a model system to examine mechanisms contributing to translational control including initiation and termination
Intrinsically stretchable and transparent thin-film transistors based on printable silver nanowires, carbon nanotubes and an elastomeric dielectric.
Thin-film field-effect transistor is a fundamental component behind various mordern electronics. The development of stretchable electronics poses fundamental challenges in developing new electronic materials for stretchable thin-film transistors that are mechanically compliant and solution processable. Here we report the fabrication of transparent thin-film transistors that behave like an elastomer film. The entire fabrication is carried out by solution-based techniques, and the resulting devices exhibit a mobility of ∼30 cm(2) V(-1) s(-1), on/off ratio of 10(3)-10(4), switching current >100 μA, transconductance >50 μS and relative low operating voltages. The devices can be stretched by up to 50% strain and subjected to 500 cycles of repeated stretching to 20% strain without significant loss in electrical property. The thin-film transistors are also used to drive organic light-emitting diodes. The approach and results represent an important progress toward the development of stretchable active-matrix displays
Minimizing the fluctuation of resonance driving terms in dynamic aperture optimization
Dynamic aperture (DA) is an important nonlinear property of a storage ring
lattice, which has a dominant effect on beam injection efficiency and beam
lifetime. Generally, minimizing both resonance driving terms (RDTs) and
amplitude dependent tune shifts is an essential condition for enlarging the DA.
In this paper, we study the correlation between the fluctuation of RDTs along
the ring and the DA area with double- and multi-bend achromat lattices. It is
found that minimizing the RDT fluctuations is more effective than minimizing
RDTs themselves in enlarging the DA, and thus can serve as a very powerful
indicator in the DA optimization. Besides, it is found that minimizing
lower-order RDT fluctuations can also reduce higher-order RDTs, which are not
only more computationally complicated but also more numerous. The effectiveness
of controlling the RDT fluctuations in enlarging the DA confirms that the local
cancellation of nonlinear effects used in some diffraction-limited storage ring
lattices is more effective than the global cancellation
- …