121 research outputs found
Determination of the mimic epitope of the M-like protein adhesin in swine Streptococcus equi subsp. zooepidemicus
<p>Abstract</p> <p>Background</p> <p>The M-like protein, also known as SzP, is expressed on the surface of <it>Streptococcus equi </it>subsp. z<it>ooepidemicus </it>(<it>S</it>. z<it>ooepidemicus</it>). Previous studies demonstrated that SzP is similar to M protein of group A <it>Streptococcus </it>in the structure and characteristics of antiphagocytosis. The M protein is an adhesin that can bind to the host cells, however it is not known whether the SzP of <it>S</it>. z<it>ooepidemicus </it>also functions as an adhesin. We conducted an investigation to determine SzP as an adhesin, and one SzP epitope was identified to be responsible for mediating binding to HEp-2 cells.</p> <p>Methods</p> <p>The gene encoding SzP was expressed in <it>E. coli</it>, and the purified recombinant SzP (rSzP) was recognized by rabbit anti-<it>S</it>. z<it>ooepidemicus </it>antibodies using immunoblot. Furthermore, the adherence of <it>S</it>. z<it>ooepidemicus </it>to HEp-2 cells was inhibited by anti-rSzP antibodies in a dose-dependent manner. We employed a random 12-peptide phage display library for screening of immunodominant mimics of the SzP, which were recognized by an anti-SzP specific monoclonal antibody (mAb 2C8). Initial positive phage clones were identified by ELISA, followed by assays to determine the adherence-inhibiting ability of the peptide.</p> <p>Results</p> <p>Ten out of fourteen selected positive clones showed high reactivity that effectively inhibited the binding of mAb 2C8 to rSzP. The motif XSLSRX was highly conserved among six of the ten clones.</p> <p>Conclusion</p> <p>Collectively, our findings suggest that the motif XSLSRX may represent an immunodominant mimic epitope of the SzP of <it>S</it>. z<it>ooepidemicus </it>strain ATCC 35246, and that the same epitope may be used to mediate SzP binding to HEp-2 cells.</p
MR imaging of intracranial solitary fibrous tumor: a retrospective study of 7 cases
Objective: To investigate the MR imaging diagnostic features of intracranial solitary fibrous tumors (ISFTs).Materials and methods: Seven patients (mean age of 52.9 years; M:F=3:4) with histopathologically proven ISFTs were identified at our institute. Clinical presentations and pathological features were reviewed. MR Imaging findings including signal intensity, gadopentetate dimeglumine enhanced pattern, and diffusion-weighted imaging (DWI) characterization of the tumors were retrospectively evaluated.Results: Six tumors showed a multi-lobular contour. Five tumors showed heterogeneous signal intensity, and two tumors showed homogeneous signal intensity on T1WI. Low signal intensity linear, curved or interlacing lines were observed within the tumors in all seven cases. Seven tumors demonstrated moderate or strong enhancement, six showed heterogeneous enhancement, and one homogenous enhancement. All tumors showed heterogeneous signal intensity on DWI.A ring–like high signal intensity band distributed around within the tumor was noted in six cases on DWI.Conclusion: Diagnostic evidence for ISFT on MR image includes heterogeneous signal intensity, intense enhancement of T2 signal intensity, low signal intensity lines within the tumor, heterogeneous signal intensity on DWI and a ring-like band around the tumor on DWI.Keywords: Intracranial Solitary Fibrous Tumor, Magnetic resonance imaging, Diffusion-weighted Imaging
MR imaging of intracranial solitary fibrous tumor: a retrospective study of 7 cases
Objective: To investigate the MR imaging diagnostic features of
intracranial solitary fibrous tumors (ISFTs). Materials and methods:
Seven patients (mean age of 52.9 years; M:F=3:4) with
histopathologically proven ISFTs were identified at our institute.
Clinical presentations and pathological features were reviewed. MR
Imaging findings including signal intensity, gadopentetate dimeglumine
enhanced pattern, and diffusion-weighted imaging (DWI) characterization
of the tumors were retrospectively evaluated. Results: Six tumors
showed a multi-lobular contour. Five tumors showed heterogeneous signal
intensity, and two tumors showed homogeneous signal intensity on T1WI.
Low signal intensity linear, curved or interlacing lines were observed
within the tumors in all seven cases. Seven tumors demonstrated
moderate or strong enhancement, six showed heterogeneous enhancement,
and one homogenous enhancement. All tumors showed heterogeneous signal
intensity on DWI.A ring\u2013like high signal intensity band
distributed around within the tumor was noted in six cases on DWI.
Conclusion: Diagnostic evidence for ISFT on MR image includes
heterogeneous signal intensity, intense enhancement of T2 signal
intensity, low signal intensity lines within the tumor, heterogeneous
signal intensity on DWI and a ring-like band around the tumor on DWI
PAN: Pulse Ansatz on NISQ Machines
Variational quantum algorithms (VQAs) have demonstrated great potentials in
the NISQ era. In the workflow of VQA, the parameters of ansatz are iteratively
updated to approximate the desired quantum states. We have seen various efforts
to draft better ansatz with less gates. In quantum computers, the gate ansatz
will eventually be transformed into control signals such as microwave pulses on
transmons. And the control pulses need elaborate calibration to minimize the
errors such as over-rotation and under-rotation. In the case of VQAs, this
procedure will introduce redundancy, but the variational properties of VQAs can
naturally handle problems of over-rotation and under-rotation by updating the
amplitude and frequency parameters. Therefore, we propose PAN, a native-pulse
ansatz generator framework for VQAs. We generate native-pulse ansatz with
trainable parameters for amplitudes and frequencies. In our proposed PAN, we
are tuning parametric pulses, which are natively supported on NISQ computers.
Considering that parameter-shift rules do not hold for native-pulse ansatz, we
need to deploy non-gradient optimizers. To constrain the number of parameters
sent to the optimizer, we adopt a progressive way to generate our native-pulse
ansatz. Experiments are conducted on both simulators and quantum devices to
validate our methods. When adopted on NISQ machines, PAN obtained improved the
performance with decreased latency by an average of 86%. PAN is able to achieve
99.336% and 96.482% accuracy for VQE tasks on H2 and HeH+ respectively, even
with considerable noises in NISQ machines.Comment: 13 pages, 13 figure
Towards Advantages of Parameterized Quantum Pulses
The advantages of quantum pulses over quantum gates have attracted increasing
attention from researchers. Quantum pulses offer benefits such as flexibility,
high fidelity, scalability, and real-time tuning. However, while there are
established workflows and processes to evaluate the performance of quantum
gates, there has been limited research on profiling parameterized pulses and
providing guidance for pulse circuit design. To address this gap, our study
proposes a set of design spaces for parameterized pulses, evaluating these
pulses based on metrics such as expressivity, entanglement capability, and
effective parameter dimension. Using these design spaces, we demonstrate the
advantages of parameterized pulses over gate circuits in the aspect of duration
and performance at the same time thus enabling high-performance quantum
computing. Our proposed design space for parameterized pulse circuits has shown
promising results in quantum chemistry benchmarks.Comment: 11 Figures, 4 Table
RobustState: Boosting Fidelity of Quantum State Preparation via Noise-Aware Variational Training
Quantum state preparation, a crucial subroutine in quantum computing,
involves generating a target quantum state from initialized qubits. Arbitrary
state preparation algorithms can be broadly categorized into arithmetic
decomposition (AD) and variational quantum state preparation (VQSP). AD employs
a predefined procedure to decompose the target state into a series of gates,
whereas VQSP iteratively tunes ansatz parameters to approximate target state.
VQSP is particularly apt for Noisy-Intermediate Scale Quantum (NISQ) machines
due to its shorter circuits. However, achieving noise-robust parameter
optimization still remains challenging.
We present RobustState, a novel VQSP training methodology that combines high
robustness with high training efficiency. The core idea involves utilizing
measurement outcomes from real machines to perform back-propagation through
classical simulators, thus incorporating real quantum noise into gradient
calculations. RobustState serves as a versatile, plug-and-play technique
applicable for training parameters from scratch or fine-tuning existing
parameters to enhance fidelity on target machines. It is adaptable to various
ansatzes at both gate and pulse levels and can even benefit other variational
algorithms, such as variational unitary synthesis.
Comprehensive evaluation of RobustState on state preparation tasks for 4
distinct quantum algorithms using 10 real quantum machines demonstrates a
coherent error reduction of up to 7.1 and state fidelity improvement
of up to 96\% and 81\% for 4-Q and 5-Q states, respectively. On average,
RobustState improves fidelity by 50\% and 72\% for 4-Q and 5-Q states compared
to baseline approaches.Comment: Accepted to FASTML @ ICCAD 2023. 14 pages, 20 figure
The Effect of Treadmill Training Pre-Exercise on Glutamate Receptor Expression in Rats after Cerebral Ischemia
Physical exercise has been demonstrated to be neuroprotective in both clinical and laboratory settings. However, the exact mechanism underlying this effect is unclear. Our study aimed to investigate whether pre-ischemic treadmill training could serve as a form of ischemic preconditioning in a rat model undergoing middle cerebral artery occlusion (MCAO). Thirty-six rats were divided into three groups: a sham control group, a non-exercise with operation group and an exercise with operation group. After treadmill training, ischemia was induced by occluding the MCA for 2 h, followed by reperfusion. Half of the rats in each group were sacrificed for mRNA detection of mGluR5 and NR2B 80 min after occlusion. The remaining animals were evaluated for neurological deficits by behavioral scoring and then decapitated to assess the infarct volume. The mRNA expression of mGluR5 and NR2B was detected by real-time PCR. The results suggest that pre-ischemic treadmill training may induce brain ischemic tolerance by reducing the mRNA levels of mGluR5 and NR2B, and thus, the results indicate that physical exercise might be an effective method to establish ischemic preconditioning
Biocompatible Single-Crystal Selenium Nanobelt Based Nanodevice as a Temperature-Tunable Photosensor
Selenium materials are widely used in photoelectrical devices, owing to their unique semiconductive properties. Single-crystal selenium nanobelts with large specific surface area, fine photoconductivity, and biocompatibility provide potential applications in biomedical nanodevices, such as implantable artificial retina and rapid photon detector/stimulator for optogenetics. Here, we present a selenium nanobelt based nanodevice, which is fabricated with single Se nanobelt. This device shows a rapid photo response, different sensitivities to visible light of variable wave length, and temperature-tunable property. The biocompatibility of the Se nanobelts was proved by MTT test using two cell lines. Our investigation introduced a photosensor that will be important for multiple potential applications in human visual system, photocells in energy or MEMS, and temperature-tunable photoelectrical device for optogenetics research
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