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Anggel Lagunas-Chavarría María Guadalupe Navarro-Rojero María Dolores Salvador Rut Benavente Jose Manuel Catal-Civera Amparo Borrell 《Materials》2022,15(11)
Lead-free piezoelectric powders (K0.44Na0.52Li0.04)(Nb0.82Ta0.10Sb0.04)O3 were obtained by conventional and microwave-assisted reactive heating. Firstly, the synthesis of the material was carried out following the mixed oxide route and employing both traditional methods and microwave technology. Thermogravimetry, X-ray diffraction, field emission scanning electron microscopy and electrical properties analyses were evaluated. X-ray diffraction of the powders calcined by the microwave process shows the formation of perovskite structure with orthorhombic geometry, but it is possible to observe the presence of other phases. The presence of the secondary phases found can have a great influence on the heating rate during the synthesis on which the kinetics of the reaction of formation of the piezoelectric compound depend. The calcined powder was sintered at different temperatures by conventional and non-conventional processes. The microstructure of the ceramics sintered by microwave at 1050 °C for 10 min shows perovskite cubes with regular geometry, of size close to 2–5 µm. However, the observed porosity (~8%), the presence of liquid phase and secondary phases in the microstructure of the microwave sintered materials lead to a decrease of the piezoelectric constant. The highest d33 value of 146 pC/N was obtained for samples obtained by conventional at 1100 °C 2 h compared to samples sintered by microwave at 1050 °C 10 min (~15 pC/N). 相似文献
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Anna V. Tinker Alon D. Altman Marcus Q. Bernardini Prafull Ghatage Lilian T. Gien Diane Provencher Shannon Salvador Sarah Doucette Amit M. Oza 《Current oncology (Toronto, Ont.)》2022,29(6):4354
The majority of patients with advanced, high-grade epithelial-tubo ovarian cancer (EOC) respond well to initial treatment with platinum-based chemotherapy; however, up to 80% of patients will experience a recurrence. Poly(ADP-ribose) Polymerase (PARP) inhibitors have been established as a standard of care maintenance therapy to prolong remission and prevent relapse following a response to first-line platinum-chemotherapy. Olaparib and niraparib are the PARP inhibitors currently approved for use in the first-line maintenance setting in Canada. Selection of maintenance therapy requires consideration of patient and tumour factors, presence of germline and somatic mutations, expected drug toxicity profile, and treatment access. This paper discusses the current clinical evidence for first-line PARP inhibitor maintenance therapy in patients with advanced, high-grade EOC and presents consensus statements and a treatment algorithm to aid Canadian oncologists on the selection and use of PARP inhibitors within the Canadian EOC treatment landscape. 相似文献
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Ji Chen Maureen M. Henneman Mark A. Trimble Jeroen J. Bax Salvador Borges-Neto Ami E. Iskandrian Kenneth J. Nichols Ernest V. Garcia 《Journal of nuclear cardiology》2008,15(1):127-136
Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of
patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular
[LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have
shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed
to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This
technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate
the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally
over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique
has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In
this review the phase analysis methodology is described, and its up-to-date validations are summarized. 相似文献
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Agnese Olivera-Toro Rubén Fossion Lei Li Rosa E. López-Gómez Emma López-Espinosa Ismael Jiménez-Estrada Salvador Quiroz-González 《Journal of acupuncture and meridian studies》2019,12(4):111-121
Many functional diseases are related to dysautonomia, and heart rate variability has been used to assess dysautonomia. However, heart rate variability has not been studied in Spleen-Qi deficiency syndrome (SQDS). Healthy volunteers (n = 37) and patients with SQDS (n = 67), recruited from the Clinic of the State University of Ecatepec Valley were included in the study. Outcome measures were average heart rate, standard deviation of the normal-to-normal heartbeat intervals, low frequency (LF), high frequency (HF) power, and the LF/HF ratio. Also, intestinal peristalsis, gastrointestinal symptoms (GSs), fatigue, and level of attention were measured. Standard deviation of the normal-to-normal heartbeat intervals (17 ± 2.3%) and HF (14 ± 3.1%) were lower in SQDS patients (17 ± 1.3%) than in healthy volunteers. SQDS patients had higher heart rate, LF power, LF/HF ratio, and fatigue scores (9.6 ± 1.12%, 16 ± 2.1%, 22 ± 3.8%, and 21 ± 4.1%). The fatigue correlated positively with the LF/HF ratio and negatively with HF power. The SQDS group had lower concentration performance (16.2 ± 1.9%) in the d2 test. The intestinal peristalsis showed a reduction (15 ± 1.3%) as compared with control. GS score and peristalsis correlated negatively with HF. Our results suggest that the pathology of SDQS could be associated with a low vagal tone which causes a decrease in peristalsis, increased fatigue, reduced attention, and appearance of GSs. 相似文献
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