基于Alexa的网站访问统计系统的设计

提出了一种基于Alexa的网站访问统计系统的设计与实现方法,该系统利用了XML、Hibernate等技术实现了数据的采集和分析,能自动记录和统计网站的访问情况,为网站评测提供科学依据.     

Single-particle visualization of assembly: I. Dimerization in a planar zone

Single-particle fluorescence microscopy of association/dissociation is required for analysis of biological assembly reactions. Toward achieving this goal, Wang et al. (J. Microsc., 2004, 213 , 101–109) used molten agarose to concentrate thermally diffusing particles in a thin zone of solution next to the surface of a coverglass (plane of concentration). The present study details the first real-time, single-particle analysis of the association/dissociation of thermally diffusing particles in the plane of concentration. The test particles were procapsids of bacteriophage λ (radius = 31 nm). Quantification of thermal motion was developed and used to determine whether co-diffusing particles were bound to each other. The data are explained by (1) the presence of a molten agarose-generated barrier that is 93–155 nm from the coverglass surface, and (2) non-random orientation of procapsid dimers in the plane of concentration.     

Performance and predictability of a new large diameter contact lens design in keratoconic corneae

ObjectivesTo evaluate the clinical performance and predictability using corneal topography in the fitting of a new large-diameter rigid gas permeable (RGP) contact lens design in eyes with keratoconus (KCN).MethodsThis study presents a review of eyes fitted with Alexa ES lenses for nonsurgical optimisation of visual correction. Anterior steep simulated keratometry (sim-K steep), corneal diameter (HVID), the Curvature at the apex in diopters (Cc), and distance from the corneal apex to the centre of the cornea (Lc) in millimetres derived from the Cone Location and Magnitude Index (CLMI) were recorded. Visual acuity, mean wearing time, final sagittal depth and adverse events were also recorded. Correlations between topographic indices and base curve were evaluated using the Pearson correlation coefficient.ResultsForty-six eyes from 26 patients (19 males/ 7 females) were included. Mean visual acuity improved from 0.49 ± 0.32 with glasses, to -0.02 ± 0.10 with the contact lens. The mean daily wear time was 12.19 ± 1.96 hours. No complications were detected in 95.65% of the eyes [95% CI (83.9%-99.2%)] but two episodes of non-infectious keratitis. The average sagittal depth of the lenses fitted was 0.425 ± 0.15 mm, and it was positively correlated with the Cc value (r² = 0.66, p< 0.0001, n=46) derived from the CLMI index of the pre-fitting topography.ConclusionsCorneoscleral RGP contact lenses are a safe, and effective alternative for managing KCN patients to corneal lenses. Also, clinical data derived from the corneal topography could be used to help to decide the first diagnostic lens to be assessed, easing the overall fitting process.     

Do smart speaker skills support diverse audiences?

Smart speakers with voice assistants like Google Home or Amazon Alexa are increasingly popular and essential in our daily lives due to their convenience of issuing voice commands. Ensuring that these voice assistants are equitable to different population subgroups is crucial. In this paper, we present the first framework, AudioAcc, to help evaluate the performance of various accents. AudioAcc takes in videos from YouTube and generates composite commands. We further propose a new metric called Consistency of Results (COR) that developers can use to avoid the incorrect translation of the produced results by rewriting the skill to improve the Word Error Rate (WER) performance. We evaluate AudioAcc on complete sentences extracted from YouTube videos. The result reveals that our composite sentences generated by AudioAcc are close to the complete sentences. Our evaluation of diverse audiences shows that first, speech from native speakers, particularly Americans, exhibits the best WER performance by 9.5% in comparison to speech from other native and nonnative speakers. Second, speech from American professional speakers has significantly more fairness and the best WER performance by 8.3% in comparison to speech from German professional speakers and German and American amateur speakers. Moreover, we show that using the COR metric could help developers to rewrite the skill to improve the WER accuracy, which we used to improve the accuracy of the Russian accent.     

Rise-Time of FRET-Acceptor Fluorescence Tracks Protein Folding

Uniform labeling of proteins with fluorescent donor and acceptor dyes with an equimolar ratio is paramount for accurate determination of Förster resonance energy transfer (FRET) efficiencies. In practice, however, the labeled protein population contains donor-labeled molecules that have no corresponding acceptor. These FRET-inactive donors contaminate the donor fluorescence signal, which leads to underestimation of FRET efficiencies in conventional fluorescence intensity and lifetime-based FRET experiments. Such contamination is avoided if FRET efficiencies are extracted from the rise time of acceptor fluorescence upon donor excitation. The reciprocal value of the rise time of acceptor fluorescence is equal to the decay rate of the FRET-active donor fluorescence. Here, we have determined rise times of sensitized acceptor fluorescence to study the folding of double-labeled apoflavodoxin molecules and show that this approach tracks the characteristics of apoflavodoxinʼs complex folding pathway.     

Using conventional fluorescent markers for far-field fluorescence localization nanoscopy allows resolution in the 10-nm range

We present a novel technique of far-field localization nanoscopy combining spectral precision distance microscopy with widely used fluorochromes like the Green Fluorescent Protein (GFP) derivatives eGFP, EmGFP, Yellow Fluorescent Protein (YFP) and eYFP, synthetic dyes like Alexa 488 and Alexa 568, as well as fluoresceine derivates. Spectral precision distance microscopy allows the surpassing of conventional resolution limits in fluorescence far-field microscopy by precise object localization after the optical isolation of single signals in time. Based on the principles of this technique, our novel nanoscopic method was realized for laser optical precision localization and image reconstruction with highly enhanced optical resolution in intact cells. This allows for spatial assignment of individual fluorescent molecules with nanometre precision. The technique is based on excitation intensity dependent reversible photobleaching of the molecules used combined with fast time sequential imaging under appropriate focusing conditions. A meaningful advantage of the technique is the simple applicability as a universal tool for imaging and investigations to the major part of already available preparations according to standard protocols. Using the above mentioned fluorophores, the positions of single molecules within cellular structures were determined by visible light with an estimated localization precision down to 3 nm; hence distances in the range of 10–30 nm were resolved between individual fluorescent molecules allowing to apply different quantitative structure analysis tools.     

基于Alexa排名的饮料工业相关开放存取资源的检索与获取

通过简介Alexa排名网站浏览、检索的方法,介绍了获取国内外饮料工业相关高质量开放存取资源的途径,以期为相关从业人员提供文献保障。     

Fiber laser based two-photon FRET measurement of calmodulin and mCherry-E(0)GFP proteins

The speed and accuracy of Förster resonance energy transfer (FRET) measurements can be improved by rapidly alternating excitation wavelengths between the donor and acceptor fluorophore. We demonstrate FRET efficiency measurements based on a fiber laser and photonic crystal fiber as the source for two‐photon excitation (TPE). This system offers the potential for rapid wavelength switching with the benefits of axial optical sectioning and improved penetration depth provided by TPE. Correction of FRET signals for cross excitation and cross emission was achieved by switching the excitation wavelength with an electrically controlled modulator. Measurement speed was primarily limited by integration times required to measure fluorescence. Using this system, we measured the FRET efficiency of calmodulin labeled with Alexa Fluor 488 and Texas Red dyes. In addition, we measured two‐photon induced FRET in an E⁰GFP‐mCherry protein construct. Results from one‐photon and two‐photon excitation are compared to validate the rapid wavelength switched two‐photon measurements. Microsc. Res. Tech. 75:837–843, 2012. © 2011 Wiley Periodicals, Inc.     

Fluorescence microscopy of colour-tagged nanoparticles that are undergoing thermal motion

To bypass limitations of conventional biochemical analysis, single‐particle biochemical analysis is used. To improve single‐particle biochemical analysis, procedures are needed to keep nanometre‐sized particles in focus while the particles are undergoing thermal motion. A simple, inexpensive procedure is developed here for keeping particles in focus during the continuous observing/discriminating/recording of two different particles, both of which are undergoing thermal motion. This procedure concentrates the particles in a plane of solution that is in focus when the cover glass surface is in focus. An essential component of the procedure is the addition of molten, low‐melt agarose to the specimen. Motionless binding to glass is inhibited by inclusion of anti‐stick additives in the specimen. Both carrier protein (gelatin) and non‐ionic detergent (Triton X‐100) are anti‐stick additives successfully used here. Intact bacteriophages T3 and T7 are used as model particles, in anticipation of the use of the procedures developed here for the analysis of the assembly of bacteriophages. Observing/discriminating/recording of colour‐tagged bacteriophages T3 and T7 is achieved at video frame rate with image splitting to discriminate colours.     

Bad Mood: On Design and ‘Empathy’

Evocative design is not only concerned with enriching our experience of our environment: it can also be used to seduce us into consuming. Empathy is as crucial to this strategy of entrapment as it is to designing with more magnanimous aims in mind. Benjamin H Bratton , Professor of Visual Arts and Director of the Center for Design and Geopolitics at the University of California, San Diego, reflects on the matter, and considers whether the moodlessness that defines seemingly empathy-free design is necessarily a bad thing.