Quantum speed limit for complex dynamics

Quantum speed limit focuses on the minimum time scale for a fixed mission and hence is important in quantum information where fast dynamics is usually beneficial. Recently an operational definition of quantum speed limit (OQSL) was proposed, which reveals the intrinsic minimum time for time-independent Hamiltonians. However, a general method to evaluate the OQSL for time-dependent Hamiltonians, especially when noises are involved, is still in lack. Hereby we provide the expression of OQSL for a certain type of time-dependent Hamiltonians and propose a three-step (classification-regression-calibration) methodology based on machine learning for the evaluation of OQSL in complex dynamics.Comment: 24 pages, 14 figures, 1 tabl

Quantification of substance P mRNA expression in the midbrain of ovariectomized migraine rats with SYBR green I real-time polymerase chain reaction

This study was designed to develop a SYBR green I-based real-time polymerase chain reaction (RTPCR) for quantitative detection of substance P (SP) mRNA in the midbrain of ovariectomized migraine rats and to evaluate the effects of estradiol on the mRNA expression of SP in order to shed light on the mechanisms underlying the pathogenesis of migraine and estrogen-conferred protection against migraine. 24 female rats were randomly assigned to the following groups: A: non-migraine controls; B: migraines; C, migraine rats receiving low estradiol; D, migraine rats receiving high estradiol. One week following ovariectomy, migraine was induced in groups B, C and D by nitroglycerin (i.p.). Behavior changes before and after migraine was examined. A SYBR green I-based RT-PCR assay was established to measure the absolute levels of SP mRNA in the midbrain. Behavioral changes in group D were significantly mitigated when compared with those in group B, whereas no marked behavioral changes were noted in groups C and B. In addition, mRNA copies of SP in group B were remarkably lower than group A, while the level of SP mRNA in both groups C and D was higher than group B, although no significance was reached (P > 0.05). SP mRNA expression decreased in the midbrain of migraine rats when compared with the non-migraine controls. High doses of estrogen partially restored SP expression in migraine rats and reduce migraine attack. Our study validated the SYBR green I-based RT-PCR technique for quantitative detection of SP mRNA.Keywords: Substance P, migraine, estrogen, midbrain, real-time quantitative polymerase chain reaction, ratsAfrican Journal of Biotechnology Vol. 9(34), pp. 5481-5487, 23 August, 201

A selective pretreatment method for determination of endogenous active brassinosteroids in plant tissues: double layered solid phase extraction combined with boronate affinity polymer monolith microextraction

BACKGROUND: Brassinosteriods (BRs), a group of important phytohormones, have various effects on plant growth and development. However, their physiological functions in plants have not been fully understood to date. Endogenous BRs in plant tissue are extremely low and the elucidation of BRs functions relies on sensitive detection method. Reported methods for the determination of BRs required large amount of plant tissue, tedious pretreatment process, and were lack of selectivity. Therefore, development of a simple and selective method for the sensitive quantification of BRs is highly needed. RESULTS: We established a pretreatment method of BRs in plant tissues by employing double layered solid phase extraction (DL/SPE) combined with boronate affinity polymer monolith microextraction (BA/PMME). After the initial depigmentation with DL/SPE cartridge, BA/PMME was employed to selectively extract BRs from sample matrix. Uniquely, most sample matrix was successfully removed by BA monolith purification. Using this method, BRs was determined by liquid chromatography-mass spectrometry (LC-MS). Endogenous active BRs could be detected in only 1 g fresh weigh (FW) leaves or 0.5 g FW flower tissues. CONCLUSION: A DL/SPE-BA/PMME pretreatment method for the determination of endogenous brassinosteroids in plant tissues was developed and validated. The proposed method was sensitive and selective. Besides, it may be further developed for the determination of other BRs including their precursors and conjugates

Regio- and Stereoselective Synthesis of Tetrasubstituted Alkenes via Ruthenium(II)-Catalyzed C–H Alkenylation/Directing Group Migration

Herein we report the regio- and stereoselective synthesis of tetrasubstituted alkenes from N-carbamoyl indoles and alkynes via ruthenium(II)-catalyzed C−H alkenylation/directing group migration, in which the carbamoyl directing group is endowed with a dual role of auxiliary group and migrating acylation reagent via C−N bond cleavage. This method features broad substrate scope, high atom- and step-economy, good functional group tolerance and mild redox-neutral conditions at room temperature. A series of structurally diverse tetrasubstituted alkenes were synthesized in good to excellent yields, highlighting the efficiency of this method

Photonic Memristor for Future Computing: A Perspective

Photonic computing and neuromorphic computing could address the inherent limitations of traditional von Neumann architecture and gradually invalidate Moore’s law. As photonics applications are capable of storing and processing data in an optical manner with unprecedented bandwidth and high speed, twoâ terminal photonic memristors with a remote optical control of resistive switching behaviors at defined wavelengths ensure the benefit of onâ chip integration, low power consumption, multilevel data storage, and a large variation margin, suggesting promising advantages for both photonic and neuromorphic computing. Herein, the development of photonic memristors is reviewed, as well as their application in photonic computing and emulation on optogeneticsâ modulated artificial synapses. Different photoactive materials acting as both photosensing and storage media are discussed in terms of their opticalâ tunable memory behaviors and underlying resistive switching mechanism with consideration of photogating and photovoltaic effects. Moreover, lightâ involved logic operations, systemâ level integration, and lightâ controlled artificial synaptic memristors along with improved learning tasks performance are presented. Furthermore, the challenges in the field are discussed, such as the lack of a comprehensive understanding of microscopic mechanisms under light illumination and a general constraint of inferior nearâ infrared (NIR) sensitivity.The development of photonic memristors and their application in photonic computing and emulation on optogeneticsâ modulated artificial synapses are reviewed. Photoactive materials as photosensing and storage media are discussed, considering their opticalâ tunable memory behavior and resistive switching mechanism including photogating and photovoltaic effect. Lightâ involved logic operations, system level integration, and artificial synaptic memristors along with improved learning tasks performance are presented.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153103/1/adom201900766.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153103/2/adom201900766_am.pd

Cross-cultural validation of the Health Care Provider HIV/AIDS Stigma Scale (HPASS) in China

The study aimed to validate the Health Care Provider HIV/AIDS Stigma Scale among medical staff in China. The validation was conducted in four steps from March to December 2017: translation and back-translation; content validity test with six experts; test–retest reliability testing with 63 medical staff with 2 weeks interval; and structural validation with 349 medical staff from 52 hospitals with a convenience sample,using exploratory factor analysis,including principal component analysis and varimax rotation. The scale content validity index average was 0.88, while for test–retest reliability, the ICC was 0.87. Three factors of “discrimination”, “prejudice” and “stereotype” with 16 items were extracted and explained 59.61% variance. The Cronbach’s alpha value for the total scale was of 0.88, and for the three factors, the values were 0.89, 0.86 and 0.74, respectively. The discrimination factor showed identical means between Canadian medical students and Chinese medical staff, while the prejudice and stereotype factors had higher mean scores in the Chinese sample. The three-factor structure of Health Care Provider HIV/AIDS Stigma Scale was confirmed in Chinese medical staff with a simpler solution. This could provide a basis for trans-cultural application and comparison