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1.
Theriogenology ; 141: 82-90, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31518732

RESUMO

Relative to alanine and serine amino acid levels, glutamine is highly abundant in follicular fluid, and is an important source of energy required for oocyte maturation and embryo development. Thus, glutamine is an essential component of in vitro embryo culture media. However, glutamine has poor stability and degrades spontaneously in solution to form ammonia and pyrrolidonecarboxylic acid. In the present study, we aimed to explore the effect of substituting l-glutamine with glycine-glutamine, a more stable glutamine, on development of early parthenogenetic embryos and in vitro fertilization (IVF) embryos in bovine. Results revealed that glycine-glutamine can significantly increase cleavage rate (parthenogenetic embryos:87.24% vs. 72.61%, IVF embryos:89.33% vs. 83.79%, P < 0.01), blastocyst number (parthenogenetic embryos:24.98% vs. 18.07%, IVF embryos:33.53% vs. 27.29%, P < 0.01), and blastocyst number (parthenogenetic embryos:96 vs. 76, IVF embryos:114 vs. 109, P < 0.01), reduce blastocyst apoptosis (parthenogenetic embryos:3.72% vs. 6.65%, IVF embryos:2.53% vs.6.23%, P < 0.01), alleviate embryo ammonia toxicity, and reduce the content of reactive oxygen species (ROS) compared with the l-glutamine. In addition, glycine-glutamine can alter epigenetic reprogramming by increasing the expression of HDAC1 (Histone Deacetylase 1) and decreasing the relative expression levels of H3K9 acetylation in early parthenogenetic embryos and IVF embryos. From our present study, we concluded that glycine-glutamine is an effective substitute of glutamine in modified synthetic oviduct fluid with amino acids (mSOFaa).

2.
J Nanosci Nanotechnol ; 20(2): 909-917, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383086

RESUMO

Tailored broussonetia-like NiCo2O4 is grown on carbon cloth using tri-sodium citrate assisted hydrothermal method. The chelating effect of citric ions has been utilized to investigate the morphological and structural evolution of NiCo2O4 on carbon cloth, which have been illustrated by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectra. The results demonstrate that the morphological alteration of NiCo2O4 from single nanowire to broussonetia-like structure has been detected after the addition of tri-sodium citrate. Citric ion plays a crucial role as an electrostatic stabilizer in determining this unique structure. When used as binder-free electrode in aqueous supercapacitors, the broussonetia-like NiCo2O4 electrode exhibits a specific capacitance of 527.9 F g-1 at a current density of 0.5 A g-1. Additionally, an asymmetric supercapacitor is further assembled using NiCo2O4 as the positive electrode and activated carbon as negative electrode. The device exhibits a maximum energy of 26.4 Wh kg-1 at power density of 800 W kg-1. A long-term cycling stability with 82% capacitance retention is maintained after 20,000 cycles at a current density of 5 A g-1, indicating the practical applicability of the tested device.

3.
J Control Release ; 2019 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-31672624

RESUMO

The macrophages mediated inflammation participates in every stage of atherosclerosis. Attenuation of macrophages inflammatory responses by active ingredients in atherosclerotic plaques is benefit to atherosclerotic stabilization and regression, but meanwhile, it is highly desired to develop accurate therapeutics for reducing off-target effects. Previous studies revealed that the apoptotic bodies are effectively recognized and engulfed by macrophages own to increased exposure of phosphatidylserine (PtdSer), which is regarded as a key "eat-me" signal. To achieve optimal delivery efficiency, an apoptotic body biomimic liposome (AP-Lipo) is constructed by decorating PtdSer and DSPE-PEG2000-cRGDfK onto the surface of liposome for selectively delivering pioglitazone (PIO), a peroxisome proliferator-activated receptor γ (PPARγ) agonist, into atherosclerotic macrophages while minimizing its side effects. Compared with unmodified liposome, AP-Lipo is more effective to recognize and penetrate the activated vascular endothelial monolayer, target pro-inflammatory macrophages and suppress the inflammation by upreglation of anti-inflammatory cytokines in vitro. Moreover, AP-Lipo can effectively target to atherosclerotic plaques and imped the progression of atherosclerosis by upregulating anti-inflammatory macrophages number and stabilizing the atherosclerotic plaques. In summary, this design imitates the characteristic of apoptotic body and provides a potential drug delivery system for atherosclerosis and other diseases, which attribute to inflammation mediated by macrophages.

4.
Radiology ; : 190467, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31687918

RESUMO

Background Although chemical shift-encoded (CSE) MRI proton density fat fraction (PDFF) is the current noninvasive reference standard for liver fat quantification, the liver is more frequently imaged with CT. Purpose To validate quantitative CT measurements of liver fat against the MRI PDFF reference standard. Materials and Methods In this prospective study, 400 healthy participants were recruited between August 2015 and July 2016. Each participant underwent same-day abdominal unenhanced quantitative CT with a calibration phantom and CSE 3.0-T MRI. CSE MRI liver fat measurements were used to calibrate an equation to adjust CT fat measurements and put them on the PDFF measurement scale. CT and PDFF liver fat measurements were plotted as histograms, medians, and interquartile ranges compared; scatterplots and Bland-Altman plots obtained; and Pearson correlation coefficients calculated. Receiver operating characteristic curves including areas under the curve were evaluated for mild (PDFF, 5%) and moderate (PDFF, 14%) steatosis thresholds for both raw and adjusted CT measurements. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Results Four hundred volunteers (mean age, 52.6 years ± 15.2; 227 women) were evaluated. MRI PDFF measurements of liver fat ranged between 0% and 28%, with 41.5% (166 of 400) of participants with PDFF greater than 5%. Both raw and adjusted quantitative CT values correlated well with MRI PDFF (r2 = 0.79; P < .001). Bland-Altman analysis of adjusted CT values showed no slope or bias. Both raw and adjusted CT had areas under the receiver operating characteristic curve of 0.87 and 0.99, respectively, to identify participants with mild (PDFF, >5%) and moderate (PDFF, >14%) steatosis, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value for unadjusted CT was 75.9% (126 of 166), 85.0% (199 of 234), 78.3% (126 of 161), and 83.3% (199 of 239), respectively, for PDFF greater than 5%; and 84.8% (28 of 33), 98.4% (361 of 367), 82.4% (28 of 34), and 98.6% (361 of 366), respectively, for PDFF greater than 14%. Results for adjusted CT were mostly identical. Conclusion Quantitative CT liver fat exhibited good correlation and accuracy with proton density fat fraction measured with chemical shift-encoded MRI. © RSNA, 2019 Online supplemental material is available for this article.

5.
Neuroreport ; 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31688420

RESUMO

Hyperactivity of the hypothalamic-pituitary-adrenal axis and impairment of the central corticotropin-releasing factor system are factors in the pathogenesis of depression. Though several antagonists of the corticotropin-releasing factor 1 receptor were effective in the recognized behavioral tests for antidepressant activity, there is still little information on the potential interactions between corticotropin-releasing factor 1 receptor inhibitors and conventional antidepressant therapy. The aim of our study was to assess the influence of CP154526, a corticotropin-releasing factor 1 receptor blocker, which presented some signs of depression. Our results revealed that CP154526 (5 and 10 mg/kg) or fluoxetine (10 mg/kg) treatment notably improved the sucrose consumption, produced anti-depressive-like behavior in open-field test, as well as immobility time in forced swimming test. The levels of interleukin-6, interleukin-1ß, tumor necrosis factor-α, and corticotropin-releasing hormone concentration in the serum were inhibited effectively by CP154526 or fluoxetine administration. Real-time quantitative PCR and western blot analysis showed the upregulated levels of brain-derived neurotrophic factor and growth associated protein 43 (GAP43) in the hypothalamus of the rats exposed to chronic unpredictable mild stress (CUMS), while different degrees of downregulation in their expression were detected after CP154526 (5 and 10 mg/kg) or fluoxetine (10 mg/kg) treatment, respectively. Thus, our data demonstrated that CP154526 exhibited antidepressant effect in CUMS rats, which might be mediated by decreasing the brain-derived neurotrophic factor and GAP43 expression in the hypothalamus.

6.
Cells ; 8(11)2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31689969

RESUMO

MicroRNAs (miRNAs) are important negative regulators of genes involved in physiological and pathological processes in plants and animals. It is worth exploring whether plant miRNAs play a cross-kingdom regulatory role in animals. Herein, we found that plant MIR167e-5p regulates the proliferation of enterocytes in vitro. A porcine jejunum epithelial cell line (IPEC-J2) and a human colon carcinoma cell line (Caco-2) were treated with 0, 10, 20, and 40 pmol of synthetic 2'-O-methylated plant MIR167e-5p, followed by a treatment with 20 pmol of MIR167e-5p for 0, 24, 48, and 72 h. The cells were counted, and IPEC-J2 cell viability was determined by the MTT and EdU assays at different time points. The results showed that MIR167e-5p significantly inhibited the proliferation of enterocytes in a dose- and time-dependent manner. Bioinformatics prediction and a luciferase reporter assay indicated that MIR167e-5p targets ß-catenin. In IPEC-J2 and Caco-2 cells, MIR167e-5p suppressed proliferation by downregulating ß-catenin mRNA and protein levels. MIR167e-5p relieved this inhibition. Similar results were achieved for the ß-catenin downstream target gene c-Myc and the proliferation-associated gene PCNA. This research demonstrates that plant MIR167e-5p can inhibit enterocyte proliferation by targeting the ß-catenin pathway. More importantly, plant miRNAs may be a new class of bioactive molecules for epigenetic regulation in humans and animals.

7.
Food Chem ; : 125743, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31699563

RESUMO

To reveal the potential effects of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) on catalase (CAT), the interactions of 1-hydroxynaphthalene (1-OHNap), 9-hydroxyphenanthrene (9-OHPhe) and 1-hydroxypyrene (1-OHPyr) with CAT were investigated using multi-spectroscopic and molecular docking techniques. Fluorescence analysis showed that 1-OHNap, 9-OHPhe and 1-OHPyr can form 1:1 complex with CAT, with the binding constant of 6.31 × 103, 1.03 × 104 and 2.96 × 105 L mol-1 at 17 °C. Thermodynamic and docking parameters demonstrated that van der Waals' force, hydrogen bonds and hydrophobic interactions dominated the three binding processes. Molecular docking also revealed the specific binding mode of OH-PAHs with CAT. Synchronous fluorescence and circular dichroism spectral results indicated that the three OH-PAHs induced varied structural changes of CAT. Furthermore, CAT activity was promoted by 9-OHPhe, but inhibited by either 1-OHNap or 1-OHPyr. Under the maximum experimental concentration of OH-PAHs, the percent change of CAT activity induced by 1-OHNap, 9-OHPhe and 1-OHPyr were 8.42%, 4.26% and 13.21%.

8.
Andrologia ; : e13470, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31701550

RESUMO

The purpose of our analysis is to identify the effect of l-carnitine (LC) and l-acetyl carnitine (LAC) on the semen parameters of men with idiopathic oligoasthenoteratozoospermia (iOAT). We performed a comprehensive search to ascertain all the trials about LC and LAC in the treatment of iOAT and compared the results, including percentage of total sperm motility, sperm concentration, percentage of forward sperm motility, semen volume, percentage of atypical forms, total motile spermatozoa, forward motile spermatozoa and the number of pregnancies between the two groups that treated with LC + LAC or placebo respectively. Seven randomised controlled trials (RCTs) involving 693 patients were included in our analysis. We found that patients who treated with LC and LAC had significantly increased the percentage of forward sperm motility (MD 6.98; 95% CI 1.06-12.90; p = .02), total motile spermatozoa (MD 16.45; 95% CI 8.10-24.79; p = .0001), forward motile spermatozoa (MD 13.01; 95% CI 11.08-14.94; p < .00001) and the number of pregnancies (OR 3.76; 95% CI 1.66-8.50; p = .002). However, no significant differences were found in other semen indicators between the two groups. LC and LAC can significantly increase part of the semen parameters. The combination therapy of LC and LAC is effective in the men with iOAT.

9.
J Pharm Pharmacol ; 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31702064

RESUMO

OBJECTIVES: Metoprolol is regarded as a first-line medicine for the treatment of myocardial infarction (MI). However, the underlying mechanisms remain largely unknown. This study aimed to investigate the involvement of miR-1 in the pharmacological function of metoprolol. METHODS: In vivo MI model was established by left anterior descending coronary artery (LAD) ligation. The effects of metoprolol on infarct size and cardiac dysfunction were determined by triphenyltetrazolium chloride staining and cardiac echocardiography, respectively. In vitro oxidative stress cardiomyocyte model was established by H2 O2 treatment. The effect of metoprolol on the expression of miR-1 and connexin43 (Cx43) was quantified by real-time PCR and western blot, respectively. The intercellular communication was evaluated by lucifer yellow dye diffusion. KEY FINDINGS: Left anterior descending ligation-induced MI injury was markedly attenuated by metoprolol as shown by reduced infarct size and better cardiac function. Metoprolol reversed the up-regulation of miR-1 and down-regulation of Cx43 in MI heart. Moreover, in H2 O2 -stimulated cardiomyocytes, overexpression of miR-1 abolished the effects of metoprolol on Cx43 up-regulation and increased intercellular communication, indicating that miR-1 may be a necessary mediator for the cardiac protective function of metoprolol. CONCLUSIONS: Metoprolol relieves MI injury via suppression miR-1, thus increasing its target protein Cx43 and improving intercellular communication.

10.
Medicine (Baltimore) ; 98(45): e17508, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31702611

RESUMO

Tibial component of total knee arthroplasty (TKA) is designed according to morphology of proximal tibia to a large extent. Owing to racial difference, current design of tibial component based on Caucasian may not be suitable for Chinese patients. Meanwhile, data of proximal tibial morphology in Chinese population is lacking. The objective of this research was to investigate proximal tibial morphology of northeast Chinese population.Computer tomography (CT) image of 164 northeast Chinese participants was collected. After three-dimensional (3D) reconstruction, size of tibia plateau and TKA resected surface were gauged to guide the design of TKA tibia prothesis in northeast Chinese population. Measurement of tibial size mainly includes tibial mediolateral length (tML), tibial medial/lateral anteroposterior length (tMAP and tLAP). Afterwards, tML/tAP ratio of tibia plateau and TKA resected surface were calculated as feature point of tibia prothesis. tMAP/tLAP ratio of TKA resected surface was calculated to represent tibial asymmetry degree. Medial and lateral posterior tibial slope (MPTS and LPTS) were also measured to give reference to posterior angle of tibia prothesis and angle of tibia osteotomy in TKA. Independent sample t test was performed to conduct statistical analysis, P < .05 was regarded as statistically significance.Northeast Chinese male has larger knee size than female. Significant difference of tML/tAP ratio was also observed between male and female on tibia plateau (1.71 ±â€Š0.07 vs 1.77 ±â€Š0.09) but not on TKA resected surface (1.60 ±â€Š0.05 versus 1.61 ±â€Š0.06). Significant difference of tMAP/tLAP ratio between male and female was also found and they were 1.31 ±â€Š1.03 and 1.11 ±â€Š0.05 respectively. Northeast Chinese female has higher PTS than male (MPTS: 9.56 ±â€Š2.96° vs 8.81 ±â€Š2.87° and LPTS: 8.57 ±â€Š3.19° vs 8.44 ±â€Š2.76°).Significant gender-difference of tibial size and asymmetry degree of tibial resected surface were found between northeast Chinese male and female. Meanwhile, northeast Chinese population has smaller knee size, larger PTS and tML/tAP ratio than that of Caucasian population. Therefore, Chinese-specific and gender-specific tibial prostheses were strongly recommended to be designed.

11.
Adv Mater ; : e1903775, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31682041

RESUMO

Domain engineered ferroelectric crystals are a type of microstructure functional material that is used widely in the area of nonlinear optics. Herein, research processes in the area of nonlinear beam shaping using domain engineered crystals in the past decade are reviewed. The newly developed design methods, such as the nonlinear Huygens-Fresnel principle, nonlinear volume holography, and caustic design, which have analogs in linear optics, are introduced. Using the proposed methods for nonlinear beam shaping, multiple function integration, generation of Airy beams, and arbitrary curved trajectories are realized. As an extra degree of freedom, orbital angular momentum of light beams is generated and manipulated through domain engineering. Discussions and future directions in this field are presented.

12.
Math Biosci Eng ; 16(6): 6209-6230, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31698558

RESUMO

Lagged settlement is a typical accident induced by shield construction in sandy cobble strata. This paper analyzed the process and mechanism of lagged settlement, results show that all phases are in accord with the characteristics of ellipsoid theory of particle flows. Based on this theory, a method for calculating coefficient of lateral earth pressure and loosened earth pressure is proposed in this research. For the coefficient of lateral earth pressure, the boundary of loosened ellipsoid is divided into two parts, the arch zone and the excavation zone, and the lateral pressure coefficients are derived respectively according to the stress state. For loosened earth pressure on tunnel, the Terzaghi earth pressure theory and Protodyakonov earth pressure theory are adapted in different conditions according to the state of loosened cobble soil. Theories developed in this study can be applied on determination of shield excavation parameters, as well as calculation of loosened earth pressure and control of tunnel support.

13.
Neurosci Lett ; : 134614, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31704317

RESUMO

Event-related brain potentials (ERPs) were recorded during a delayed character-matching (target-probe matching) task to examine the joint effects of stimulus quality (blurriness) and character frequency on the N400. The behavioral results indicated robust interactive effects of stimulus quality and character frequency on response times, suggesting the cascade of pre-lexical activation to the lexical stage. The ERP results showed an interaction between stimulus quality and character frequency on N400-like amplitude. As the N400 is basically a marker of semantic processing, these ERP findings suggested that the direct impact of stimulus blurriness on pre-lexical processing could be further cascaded to semantic processing via lexical stage. The converging behavioral and N400 evidence for the interactive effects of stimulus quality and character frequency accords well with the interactive activation (IA) model, in which stimulus quality and character frequency affect at least a common stage in a cascaded processing manner.

14.
Mol Med Rep ; 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31702031

RESUMO

The differentiation and maturation of oligodendrocyte precursor cells (OPCs) is important for remyelination in the central nervous system. Nevertheless, this process is often limited and incomplete in ischemic injury. Oligodendrocyte transcription factor 1 (Olig1) is important for the maturation of OPCs and the repair of demyelinated lesions. However, how Olig1 modulates the development of OPCs or the remyelination associated with ischemic injury remains unclear. The present study aimed to examine alterations in OPCs, and the expression of myelin and Olig1, at different time-points after focal cerebral ischemia using immunohistochemistry and western blot techniques to elucidate the role of Olig1 in the maturation of OPCs and remyelination. The present results showed that the expression of Olig1 significantly decreased at 1 day after middle cerebral artery occlusion (MCAO) and returned to normal levels from day 3 to 28. Additionally, Olig1 was found to translocate into the nucleus following ischemia in the brain. The number of OPCs in the ischemic striatum significantly declined at days 1 and 3 following MCAO, and increased at days 7, 14 and 28 compared with the control. The expression of myelin basic protein, a marker of mature oligodendrocytes and myelin, gradually decreased from day 1 to 7 after ischemia and recovered at day 14 and 28; however, the levels were lower than those in the control group. The present results indicated that the restored normal level of Olig1 following ischemia may play an important role in the maturation of OPCs through its translocation into the nucleus, where it may promote the growth and development of myelin under pathological conditions. However, this endogenous recovery mechanism fails to fully repair the demyelinated lesion. The data of the present study may help clinicians understand the expression pattern of Olig1 and its potential role in endogenous remyelination after ischemia, which may have implications for the treatment of diseases that lead to demyelination.

15.
Clin Nutr ; 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31694759

RESUMO

BACKGROUND: Previous clinical and animal studies suggested that medium-chain triglycerides (MCT) might be an alternative energy substrate for the brain and might benefit patients with Alzheimer's disease (AD), but the clinical evidence is not substantial or totally convincing. OBJECTIVE: To investigate the effects of MCT on cognitive ability in patients with mild to moderate AD and explore the changes in peripheral blood metabolomics. METHODS: A double-blind, randomized, placebo-controlled crossover study was undertaken in 53 mild to moderate AD patients. Participants were randomized between two sequences (placebo followed by MCT or MCT followed by placebo) and took MCT jelly or placebo jelly (canola oil) by mouth three times daily (total daily fat dose: 17.3 g MCT, or 19.7 g canola oil) for 30 days per phase. The primary outcome was cognition as measured by the Alzheimer's Disease Assessment Scale-Cognitive Subscale, Chinese version (ADAS-Cog-C). The secondary outcome was self-care as measured by the activities of daily living scale (ADL) and changes in plasma metabolites. RESULTS: This study showed a significant (p < 0.01) reduction in ADAS-Cog-C scores between the MCT (2.62 points below baseline) and placebo interventions (2.57 points above baseline). Data from 46 (86.8%) APOE4-/- subjects who completed the entire study were analyzed. Changes in ADL scores were not significantly different between the MCT and placebo interventions (p > 0.05). The concentrations of TC, HDL-C, ß-hydroxybutyrate and acetoacetate were significantly higher in the MCT group than in the placebo group (p < 0.05). Lysophosphatidylcholine 16:0 (LysoPC (16:0)), LysoPC (P-18:0), LysoPC (P-18:1(9Z)), LysoPC (20:2(11Z,14Z)), and LysoPC (22:5(4Z,7Z,10Z,13Z,16Z)) were significantly increased after MCT intervention, and the concentrations of LysoPC (18:0), palmitic acid, linoleic acid, oleic acid, and 7,12-dimethylbenz[a]anthracene were significantly decreased (p < 0.05), whereas no significant changes appeared after the placebo intervention. Androstenedione concentration increased after placebo intervention. Furthermore, a significant negative correlation was observed between changes in LysoPC (P-18:1(9Z)) and ADAS-Cog-C scores after MCT intervention (r = -0.1472, p < 0.05). CONCLUSIONS: MCT had positive effects on cognitive ability in mild to moderate AD patients with APOE4-/-. These effects of MCT might be related to the metabolism of LysoPC, oleic acid, linoleic acid and palmitic acid, in addition to the ketogenic effect. STUDY ID NUMBER: ChiCTR-IOR-16009737. REGISTRY WEBSITE: WHO ICTRP Search Portal - http://apps.who.int/trialsearch/Default.aspx.

16.
Org Lett ; 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31697086

RESUMO

A useful method for the enantioselective preparation of isoxazoline N-oxides via Pd-catalyzed asymmetric allylic cycloaddition of nitro-containing allylic carbonates has been developed. By using palladium complex in situ generated from Pd2(dba)3·CHCl3 and phosphoramidite L2 as a catalyst under mild conditions, the transformation afforded vinylated isoxazoline N-oxides in high yields with acceptably high enantioselectivities.

17.
Org Lett ; 2019 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-31702930

RESUMO

An efficient method for the enantioselective synthesis of cyclic ureas has been developed through Pd-catalyzed asymmetric allylic cycloaddition of readily accessible nitrogen-containing allylic carbonates with isocyanates. By using a palladium complex in situ generated from Pd2(dba)3·CHCl3 and phosphoramidite L1 or L3 as a ligand under mild reaction conditions, the process afforded imidazolidinones and tetrahydropyrimidinones with high yields and high levels of enantioselectivities.

18.
ISA Trans ; 2019 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-31585670

RESUMO

In order to guarantee the system reliability and enhance post-fault maintenance efficiency of inverters, this paper presents an current observer-based online open-switch fault diagnosis method for the voltage-source inverters (VSI). Analyzing the state space model of VSI when fault occurs, a state observer of the system is built to estimate phase currents. Once the open-switch fault occurs, the current residual vector between the estimated currents on observer and the measured currents, and fault diagnosis is realized by exploiting the featured amplitude and phase of the current residual vector. In order to realize on-line diagnosis with high reliability and speed, the average value of current residuals in a fundamental period is obtained and Clark transformation is performed so as to acquire vector angle. In addition, the sum of absolute values of measured currents is normalized to serve as the sign of fault occurrence. The simulation and experimental results show the effectiveness of proposed method.

20.
Int J Clin Pharm ; 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31654364

RESUMO

Background The prevalence of drug-related problems in patients hospitalized at respiratory care units is unknown in mainland China. Objective To identify and categorize drug-related problems in a respiratory care unit in China. Setting Respiratory care unit in a tertiary university hospital in China. Methods Clinical pharmacy services were introduced and documented during an 18-months study period. The problems were categorized using the Pharmaceutical Care Network Europe DRP classification tool V8.02. Main outcome measures Problems and causes of drug-related problems, interventions proposed, and outcome of pharmacy recommendations. Results A total of 474 patients were reviewed, 164 patients had DRPs (34.6%). Total 410 problems were identified, an average of 2.5 per patient. Treatment effectiveness was the major type of problem detected (219; 53.4%) followed by treatment safety (140; 34.1%). The most common causes of the problems were patient-related (25.8%), drug selection (24.0%), and drug use process (23.4%). Pharmacist made 773 interventions; average 1.9 per drug-related problem. A total of 96.2% of these interventions were accepted leading to solving 81.9% of the identified problems. Conclusion There is a high prevalence of drug-related problems in patients hospitalized at the respiratory unit of this clinic. Clinical pharmacists should focus on improving prescribing practice and patient counseling.

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