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1.
Opt Express ; 30(9): 14574-14585, 2022 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-35473197

RESUMEN

We report on the development of a microwave frequency standard based on a laser-cooled 171 Y b + ion trap system. The electronics , lasers, and magnetic shields are integrated into a single physical package. With over 105 ions are stably trapped, the system offers a high signal-to-noise ratio Ramsey line-shape. In comparison with previous work, the frequency instability of a 171 Y b + microwave clock was further improved to 8.5×10-13/τ for averaging times between 10 and 1000 s. Essential systematic shifts and uncertainties are also estimated.

2.
Opt Lett ; 46(23): 5882-5885, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34851914

RESUMEN

We measured the ground-state hyperfine splitting of trapped 113Cd+ ions to be 15199862855.02799(27) Hz with a fractional uncertainty of 1.8×10-14. The ions were trapped and laser-cooled in a linear quadrupole Paul trap. The fractional frequency stability was measured to be 4.2×10-13/τ, obtained from Ramsey fringes of high signal-to-noise ratios and taken over a measurement time of nearly 5 h, which is close to the short-term stability limit estimated from the Dick effect. Our result is consistent with previously reported values, but the measurement precision is four times better than the best result obtained to date.

3.
Eur Rev Med Pharmacol Sci ; 24(24): 13044-13048, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33378056

RESUMEN

As a severe and highly contagious infection, coronavirus disease (COVID-19) affects all aspects of society and has become a global public health problem. Because of the complexity of the pathology of COVID-19, it is difficult to treat. An increasing number of reports have indicated that COVID-19 may have neurological complications, including stroke. The nervous system complications of COVID-19 have gradually attracted research attention. In this review, we summarize the latest findings related to COVID 19, elaborate on the possible mechanism of COVID 19 related onset of stroke, and summarize current treatment options because an improved understanding and appropriate treatments may improve the prognosis of patients with COVID-19-related stroke.


Asunto(s)
Anosmia/fisiopatología , COVID-19/fisiopatología , Cefalea/fisiopatología , Accidente Cerebrovascular/fisiopatología , Trastornos del Gusto/fisiopatología , Enzima Convertidora de Angiotensina 2/metabolismo , Anticoagulantes/uso terapéutico , Trastornos de la Coagulación Sanguínea/complicaciones , Trastornos de la Coagulación Sanguínea/fisiopatología , COVID-19/complicaciones , COVID-19/inmunología , COVID-19/terapia , Trastornos de la Conciencia/fisiopatología , Citocinas/inmunología , Endotelio Vascular/metabolismo , Endotelio Vascular/fisiopatología , Humanos , Receptores de Coronavirus/metabolismo , Sistema Renina-Angiotensina , SARS-CoV-2 , Medias de Compresión , Accidente Cerebrovascular/etiología , Accidente Cerebrovascular/inmunología , Accidente Cerebrovascular/terapia , Terapia Trombolítica
4.
Nat Commun ; 11(1): 3054, 2020 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-32528007

RESUMEN

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

5.
Nat Commun ; 11(1): 2339, 2020 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-32393747

RESUMEN

Electron-electron interactions play a critical role in many condensed matter phenomena, and it is tempting to find a way to control them by changing the interactions' strength. One possible approach is to place a studied system in proximity of a metal, which induces additional screening and hence suppresses electron interactions. Here, using devices with atomically-thin gate dielectrics and atomically-flat metallic gates, we measure the electron-electron scattering length in graphene and report qualitative deviations from the standard behavior. The changes induced by screening become important only at gate dielectric thicknesses of a few nm, much smaller than a typical separation between electrons. Our theoretical analysis agrees well with the scattering rates extracted from measurements of electron viscosity in monolayer graphene and of umklapp electron-electron scattering in graphene superlattices. The results provide a guidance for future attempts to achieve proximity screening of many-body phenomena in two-dimensional systems.

6.
Langmuir ; 34(27): 8075-8080, 2018 07 10.
Artículo en Inglés | MEDLINE | ID: mdl-29897774

RESUMEN

We demonstrate rapid [∼mm3/(h·L)] organic ligand-free self-assembly of three-dimensional, >50 µm single-domain microassemblies containing up to 107 individual aligned nanoparticles through a scalable aqueous process. Organization and alignment of aqueous solution-dispersed nanoparticles are induced by decreasing their pH-dependent surface charge without organic ligands, which could be temperature-sensitive or infrared light absorbing. This process is exhibited by transforming both dispersed iron oxide hydroxide nanorods and lithium yttrium fluoride nanoparticles into high packing density microassemblies. The approach is generalizable to nanomaterials with pH-dependent surface charge (e.g., oxides, fluorides, and sulfides) for applications requiring long-range alignment of nanostructures as well as high packing density.

7.
Eur J Clin Microbiol Infect Dis ; 35(12): 1941-1947, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27530531

RESUMEN

This study analyzed the prevalence and antibiotic susceptibility of urogenital Ureaplasma urealyticum and Mycoplasma hominis isolated in Xi'an, China. A total of 2161 individuals from 2011 to 2015 were included, and antibiotic susceptibility tests were performed by using the Mycoplasma IST kit. Of the individuals studied, 1018 (47.11 %) were identified to be positive for urogenital mycoplasmas. The single U. urealyticum, single M. hominis, and dual U. urealyticum and M. hominis infections accounted for 772 (75.83 %), 66 (6.48 %), and 180 (17.68 %), respectively. The total positive rate was higher in females than in males (58.76 % vs. 28.86 %, p < 0.001). The highest total positive rate (48.88 %) was observed in individuals aged 25 years to 30 years. In symptomatic and asymptomatic individuals, the positive rates were both higher in females than in males (67.36 % vs. 31.02 %, p < 0.001 and 42.58 % vs. 7.69 %, p < 0.001, respectively) and individuals aged 25 years to 30 years, and those aged 30 years to 35 years had the highest positive rates (54.35 and 57.14 %, respectively). The U. urealyticum and M. hominis identified from single or dual infections displayed low resistance rates to josamycin, doxycycline, and minocycline (<10 %) in both the symptomatic and asymptomatic groups. These results suggest that females and individuals with symptoms and younger age had higher mycoplasma infection rates and that josamycin, doxycycline, and minocycline may be recommended for the clinical treatment of patients infected with urogenital mycoplasmas, irrespective of the symptoms.


Asunto(s)
Antibacterianos/farmacología , Infecciones por Mycoplasma/microbiología , Mycoplasma hominis/efectos de los fármacos , Infecciones por Ureaplasma/microbiología , Ureaplasma urealyticum/efectos de los fármacos , Adolescente , Adulto , Anciano , China/epidemiología , Farmacorresistencia Bacteriana , Femenino , Enfermedades Urogenitales Femeninas/epidemiología , Enfermedades Urogenitales Femeninas/microbiología , Humanos , Masculino , Enfermedades Urogenitales Masculinas/epidemiología , Enfermedades Urogenitales Masculinas/microbiología , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Infecciones por Mycoplasma/epidemiología , Mycoplasma hominis/aislamiento & purificación , Prevalencia , Infecciones por Ureaplasma/epidemiología , Ureaplasma urealyticum/aislamiento & purificación , Adulto Joven
8.
Neuroscience ; 290: 552-60, 2015 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-25665755

RESUMEN

Recent studies indicate that over-activation of Cdk5 is a crucial pro-death signal and Cdk5 activity inhibition provides neuroprotection in animal stroke models. However, Cdk5 inhibitors are reported to affect physiological functions of Cdk5 and lead to serious side effects. Therefore, targeting Cdk5 or its activators without affecting physiological functions of Cdk5 is a therapeutic strategy for ischemic brain injury. In this study, we examined Cdk5 activity in a rat hypoxia/ischemia (HI) injury model. Cdk5 expression was not changed after HI injury, but Cdk5 activity significantly increased, which was demonstrated by the increased phorsphorylation-phosphorylation of Tau and glucocorticoid receptor (GR), two downstream signals of Cdk5. We further showed that the levels of Cdk5 activators p35 and p39 decreased after HI injury, while p25, which is converted from p35 and has a higher activator activity on Cdk5, increased markedly after HI injury. P5, a 24-residue mimetic peptide of p35, was reported to specifically inhibit the p25/Cdk5 signal pathway in an Alzheimer's disease model. P5-TAT, which can cross the blood-brain barrier and cell membrane facilitated by TAT protein, was used in our study. We found that p5-TAT treatment did not change the levels of p35, p39, and p25, but reduced the phorsphorylation of Tau and GR, suggesting the inhibition of the p25/Cdk5 by the peptide p5-TAT. This was supported by the fact that p5 interacted with Cdk5, but not with Cdk5 activators. In addition, p5-TAT reduced cleaved caspase-3 level, a marker of neuronal apoptosis. We further demonstrated that p5-TAT pre-treatment reduced cerebral infarct volume; even when p5-TAT was delayed to be administered at 24h after HI injury, p5-TAT still promoted long-term functional recovery. Therefore, Cdk5 inhibition by the small peptide p5-TAT or its derivatives is a promising therapeutic strategy for the treatment of ischemic brain injury including hypoxic-ischemic encephalopathy and stroke.


Asunto(s)
Encéfalo/efectos de los fármacos , Quinasa 5 Dependiente de la Ciclina/antagonistas & inhibidores , Hipoxia-Isquemia Encefálica/tratamiento farmacológico , Fármacos Neuroprotectores/farmacología , Recuperación de la Función/efectos de los fármacos , Animales , Animales Recién Nacidos , Encéfalo/patología , Encéfalo/fisiopatología , Caspasa 3/metabolismo , Quinasa 5 Dependiente de la Ciclina/metabolismo , Modelos Animales de Enfermedad , Hipoxia-Isquemia Encefálica/patología , Hipoxia-Isquemia Encefálica/fisiopatología , Proteínas del Tejido Nervioso/metabolismo , Fosforilación/efectos de los fármacos , Fosfotransferasas/antagonistas & inhibidores , Fosfotransferasas/metabolismo , Distribución Aleatoria , Ratas Sprague-Dawley , Receptores de Glucocorticoides/metabolismo , Recuperación de la Función/fisiología , Proteínas tau/metabolismo
9.
Genet Mol Res ; 13(4): 10184-93, 2014 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-25501230

RESUMEN

In this study, 2 approaches were adopted to obtain good single-strand conformation polymorphism (SSCP) data for autotetraploid alfalfa; primers were added to PCR products, and fluorescent-labeled primers were utilized. PCR-SSCP conditions for a 331-bp fragment in the coding region of polygalacturonase-inhibiting protein gene 2 in alfalfa (MsPGIP2) were optimized, and the results showed that the best SSCP gel pattern could be obtained when the loading mixture was made by mixing 1 µL PCR products, 0.2 to 0.8 µL unlabeled primers (50 µM) and 4 to 16 µL loading buffer. Furthermore, the use of the fluorescent-labeled primers resulted in 2 separated electrophoresis images from 2 complementary single DNA strands, thus making the determination of alleles and idiotypes a relatively easy task. In addition, the results of sequencing prove that the determination of alleles and idiotypes were accurate based on SSCP analysis. Finally, a total of 9 alleles with 18 SNP sites were identified for MsPGIP2 in the alfalfa variety 'Algonquin'. In conclusion, MsPGIP2 possessed great genetic variation, and the addition of primers to the PCR products in combination with the fluorescent labeling of primers could significantly improve the sensitivity and resolution of SSCP analysis. This technique could be used for genetic diversity detection and marker-assisted breeding of useful genes in autopolyploid species such as alfalfa.


Asunto(s)
Dermatoglifia del ADN/métodos , Medicago sativa/genética , Proteínas de Plantas/genética , Alelos , Cartilla de ADN/química , Fluorescencia , Polimorfismo de Nucleótido Simple , Polimorfismo Conformacional Retorcido-Simple
10.
Scand J Immunol ; 78(1): 98-107, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23617779

RESUMEN

IL-17 and IL-22 are implicated in the pathogenesis of autoimmune diseases. The roles of IL-22 in the pathophysiology of myasthenia gravis (MG) remain unsettled. The aim of this study was to investigate the possible relationship between serum IL-22, IL-17 levels, anti-acetylcholine receptor antibody (anti-AChR Ab) titres and clinical parameters in patients with MG. The serum IL-22, IL-17 levels and anti-AChR Ab titres were tested by enzyme-linked immunosorbent assay (ELISA), while the expression of IL-22 and IL-17 mRNAs in peripheral blood mononuclear cells (PBMC) from healthy and MG subjects were detected by quantitative real-time PCR (qRT-PCR). Furthermore, PBMC from 12 patients with generalized MG were purified and treated with recombinant human IL-22 (rhIL-22), the IL-17 levels of supernatant were detected by ELISA. We found that the IL-17 levels were significantly increased, but IL-22 levels were significantly decreased in the serum of patients with MG compared with healthy controls. Consistantly, a significant decrease in IL-22 mRNA levels and an increase in IL-17 mRNA levels were detected in PBMC collected from patients with MG, compared with healthy controls. A negative correlation between IL-22 mRNA in PBMC, serum IL-22 and serum anti-AChR Ab levels was found in patients with MG. Moreover, in cultured MG PBMC treated with recombinant human IL-22 (rhIL-22), the IL-17 levels were decreased in a dose-dependent manner. Our findings indicated a possible role of IL-22 as a protective factor in MG.


Asunto(s)
Interleucinas/fisiología , Miastenia Gravis/inmunología , Adulto , Anciano , Autoanticuerpos/sangre , Femenino , Humanos , Interleucina-17/sangre , Interleucina-17/genética , Interleucinas/sangre , Interleucinas/genética , Masculino , Persona de Mediana Edad , Receptores Colinérgicos/inmunología
11.
J Am Chem Soc ; 134(22): 9251-62, 2012 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-22632379

RESUMEN

Single crystals of doped aniline oligomers are produced via a simple solution-based self-assembly method. Detailed mechanistic studies reveal that crystals of different morphologies and dimensions can be produced by a "bottom-up" hierarchical assembly where structures such as one-dimensional (1-D) nanofibers can be aggregated into higher order architectures. A large variety of crystalline nanostructures including 1-D nanofibers and nanowires, 2-D nanoribbons and nanosheets, 3-D nanoplates, stacked sheets, nanoflowers, porous networks, hollow spheres, and twisted coils can be obtained by controlling the nucleation of the crystals and the non-covalent interactions between the doped oligomers. These nanoscale crystals exhibit enhanced conductivity compared to their bulk counterparts as well as interesting structure-property relationships such as shape-dependent crystallinity. Furthermore, the morphology and dimension of these structures can be largely rationalized and predicted by monitoring molecule-solvent interactions via absorption studies. Using doped tetraaniline as a model system, the results and strategies presented here provide insight into the general scheme of shape and size control for organic materials.

12.
Zhong Yao Cai ; 24(10): 718-20, 2001 Oct.
Artículo en Chino | MEDLINE | ID: mdl-11822284

RESUMEN

OBJECTIVE: To provide evidences for the identification of Argyreia acuta Lour. METHOD: By descriptions and microscopic identification. RESULT: The characters including stomata covered by many glandular hairs in dorsal surface of leaf of Argyreia acuta were obvious. CONCLUSION: The result provided evidences for the identification of Argyreia acuta Lour.


Asunto(s)
Convolvulaceae/anatomía & histología , Plantas Medicinales/anatomía & histología , Hojas de la Planta/anatomía & histología , Tallos de la Planta/anatomía & histología
13.
Zhong Yao Cai ; 22(8): 389-91, 1999 Aug.
Artículo en Chino | MEDLINE | ID: mdl-12571884

RESUMEN

Pharmacognostic identification of Ampelopsis grossedentata was carried out by studying its microscopic characteristics, UV spectra and TLC. The results may provide a scientific basis for the comprehensive development and utilization of the drug.


Asunto(s)
Ampelopsis/anatomía & histología , Plantas Medicinales/anatomía & histología , Ampelopsis/química , Ampelopsis/citología , Cromatografía en Capa Delgada , Farmacognosia , Componentes Aéreos de las Plantas/anatomía & histología , Componentes Aéreos de las Plantas/química , Componentes Aéreos de las Plantas/citología , Plantas Medicinales/química , Plantas Medicinales/citología , Espectrofotometría Ultravioleta
14.
Se Pu ; 16(5): 445-7, 1998 Sep.
Artículo en Chino | MEDLINE | ID: mdl-11498926

RESUMEN

A high performance liquid chromatography-indirect photometric detection (HPLC-IPD) method for determination of sisomicin sulfate in body fluid (serum, urine, saliva, cerebrospinal fluid and fluid oozed out from wound) was established. The conditions in this method were a mobile phase solution of methyl alcohol-acetonitrile-water (20:10:70) containing nicotinamide 0.5 mmol/L, sodium 1-heptanesulfonate 5 mmol/L and phosphoric acid 0.05 mol/L, a Spherisorb C18 column (4.6 mm x 250 mm) and an UV detector with sensitivity of 0.05 Aufs (0.1 Aufs for urine). The detection wavelength was fixed at 268 nm. The average recovery for sisomicin in serum was 96.92% +/- 4.63% and the coefficients of variation were 4.75% and 5.65% for within-day and day-to-day tests respectively. The detectable limit was 0.1 ng. The concentration of sisomicin in body fluid of 4 patients was determined.


Asunto(s)
Antibacterianos/metabolismo , Líquidos Corporales/química , Cromatografía Líquida de Alta Presión/métodos , Sisomicina/metabolismo , Humanos , Fotometría/métodos
15.
Zhongguo Zhong Yao Za Zhi ; 22(2): 96-8, 127, 1997 Feb.
Artículo en Chino | MEDLINE | ID: mdl-10743200

RESUMEN

TLC was used in the qualitative study of Qing'e Pills. The contents of psoralen and isopsoralen in these pills were determined by TLC-densitometry. The proposed method can be used to control the quality of Qing'e Pills.


Asunto(s)
Medicamentos Herbarios Chinos/química , Ficusina/análisis , Furocumarinas/análisis , Cromatografía en Capa Delgada , Densitometría , Combinación de Medicamentos , Ficusina/normas , Furocumarinas/normas , Control de Calidad
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