168 research outputs found
6-Amino-3-methyl-4-(4-nitrophenyl)-1-phenylpyrazolo[3,4-b]pyridine-5-carbonitrile
The title compound, C20H14N6O2, contains four rings. The dihedral angle between the pyridine ring and the pyrazole ring is 1.9 (1)°, i.e. almost coplanar, which gives rise to a conjugated structure. The dihedral angle between the nitro-substituted phenyl ring and the pyridine ring is 76.3 (1)° and that between the pyrazole ring and the non-substituted phenyl ring is 40.5 (1)°. In the crystal structure, symmetry-related molecules are linked by N—H⋯O and C—H⋯N hydrogen bonds
Intensity-modulated Radiation Therapy Versus Para-aortic Field Radiotherapy to Treat Para-aortic Lymph Node Metastasis in Cervical Cancer: Prospective Study
Aim To compare dosimetry, efficacy, and toxicity of intensity-
modulated radiation therapy (IMRT) with para-aortic
field radiotherapy in patients with para-aortic lymph node
(PALN) metastasis of cervical cancer.
Methods This prospective study examined 60 patients
with cervical cancer with PALN metastasis who underwent
whole-pelvis radiotherapy followed by brachytherapy between
November 1, 2004 and May 31, 2008. After 3 cycles
of chemotherapy, patients were serially allocated into two
groups and treated with IMRT or para-aortic field RT at
doses of 58-68 Gy and 45-50 Gy, respectively. Treatment
response was evaluated and toxicities were assessed. Patients
in the IMRT group were treated with both para-aortic
field RT and IMRT in order to compare the exposure dose
of organs at risk.
Results In the IMRT group, the mean dose delivered to the
planning target volume was 67.5 Gy. At least 99% of the
gross tumor volume received effective coverage and radical
dose (median, 63.5 Gy; range, 54.5-66) during treatment.
IMRT plans yielded better dose conformity to the target
and better sparing of the spinal cord and small intestine
than para-aortic field RT. The IMRT patients experienced
less acute and chronic toxicities. The IMRT group also had
higher 2- and 3-year survival rates than the para-aortic RT
group (2-year, 58.8% vs 25.0%, P = 0.019; 3-year, 36.4% vs
15.6%, P = 0.016). However, no significant difference was
found in 1-year survival (67.7% vs 51.3%, P =0.201). The median
survival in the IMRT group was 25 months (range, 3 to
37 months). The actuarial overall survival, disease-free survival,
and locoregional control rates at 2 years were 67%,
77%, and 88%, respectively, in the IMRT group.
Conclusions IMRT provides better clinical outcomes than
para-aortic field radiotherapy in patients with PALN metastasis.
However, cervical local and distal recurrence remain a
problem. Long-term follow-up and studies involving more
patients are needed to confirm our results
A SWAP Gate for Spin Qubits in Silicon
With one- and two-qubit gate fidelities approaching the fault-tolerance
threshold for spin qubits in silicon, how to scale up the architecture and make
large arrays of spin qubits become the more pressing challenges. In a scaled-up
structure, qubit-to-qubit connectivity has crucial impact on gate counts of
quantum error correction and general quantum algorithms. In our toolbox of
quantum gates for spin qubits, SWAP gate is quite versatile: it can help solve
the connectivity problem by realizing both short- and long-range spin state
transfer, and act as a basic two-qubit gate, which can reduce quantum circuit
depth when combined with other two-qubit gates. However, for spin qubits in
silicon quantum dots, high fidelity SWAP gates have not been demonstrated due
to the requirements of large circuit bandwidth and a highly adjustable ratio
between the strength of the exchange coupling J and the Zeeman energy
difference Delta E_z. Here we demonstrate a fast SWAP gate with a duration of
~25 ns based on quantum dots in isotopically enriched silicon, with a highly
adjustable ratio between J and Delta E_z, for over two orders of magnitude in
our device. We are also able to calibrate the single-qubit local phases during
the SWAP gate by incorporating single-qubit gates in our circuit. By
independently reading out the qubits, we probe the anti-correlations between
the two spins, estimate the operation fidelity and analyze the dominant error
sources for our SWAP gate. These results pave the way for high fidelity SWAP
gates, and processes based on them, such as quantum communication on chip and
quantum simulation by engineering the Heisenberg Hamiltonian in silicon.Comment: 25 pages, 5 figures
Total Flavonoids from Clinopodium chinense
Doxorubicin has cardiotoxic effects that limit its clinical benefit in cancer patients. This study aims to investigate the protective effects of the total flavonoids from Clinopodium chinense (Benth.) O. Ktze (TFCC) against doxorubicin- (DOX-) induced cardiotoxicity. Male rats were intraperitoneally injected with a single dose of DOX (3 mg/kg) every 2 days for three injections. Heart samples were collected 2 weeks after the last DOX dose and then analyzed. DOX delayed body and heart growth and caused cardiac tissue injury, oxidative stress, apoptotic damage, mitochondrial dysfunction, and Bcl-2 expression disturbance. Similar experiments in H9C2 cardiomyocytes showed that doxorubicin reduced cell viability, increased ROS generation and DNA fragmentation, disrupted mitochondrial membrane potential, and induced apoptotic cell death. However, TFCC pretreatment suppressed all of these adverse effects of doxorubicin. Signal transduction studies indicated that TFCC suppressed DOX-induced overexpression of p53 and phosphorylation of JNK, p38, and ERK. Studies with LY294002 (a PI3K/AKT inhibitor) demonstrated that the mechanism of TFCC-induced cardioprotection also involves activation of PI3K/AKT. These findings indicated the potential clinical application of TFCC in preventing DOX-induced cardiac oxidative stress
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