Apex cryopreservation of several strawberry genotypes by two encapsulation-dehydration methods

This paper presents results from a study to develop cryopreservation procedures for apices of several strawberry genotypes. Five Fragaria x ananassa Duch. cultivars and two wild species (F. chiloensis and F. virginiana) have been screened using the encapsulation-dehydration method and/or a protocol which compromises vitrification and encapsulation-dehydration. Apices were encapsulated in an alginate gel, precultured on media containing high levels of sucrose (0.8 M, conventional protocol), or a combination of 0.4 M sucrose and 2 M glycerol. Recovery rates varied among genotypes (23-63%). The latter method reduced considerably the time needed for the cryogenic procedure by eliminating the pre-treatment with 0.8 M sucrose for 19 h prior to dehydration, as required by the conventional procedure.     

Intraspeaker variability in fundamental frequency stability: an age-related phenomenon?

The purpose of this investigation was to gather information on the extent to which intraspeaker variability on measures of jitter (%) and fundamental frequency standard deviation (F0 s.d.) is age related in women. Fifteen repeat productions of the vowels /i/, /a/, and /u/ from 22 young women (18-22 years) were analyzed for F0 s.d. and jitter. Findings for these young speakers were compared with those for elderly speakers tested previously (Linville and Korabic, 1987). Results indicate that the aging process brings about increases in the variability individual women demonstrate on measures of F0 stability when producing sustained vowels as steadily as possible. Further, young speakers differed markedly from elderly speakers in the pattern of frequency instability variations observed across the three vowels tested.     

Measuring the quantum state of a large angular momentum

We demonstrate a general method to measure the quantum state of an angular momentum of arbitrary magnitude. The (2F+1)x(2F+1) density matrix is completely determined from a set of Stern-Gerlach measurements with (4F+1) different orientations of the quantization axis. We implement the protocol for laser cooled Cesium atoms in the 6S(1/2)(F = 4) hyperfine ground state and apply it to a variety of test states prepared by optical pumping and Larmor precession. A comparison of input and measured states shows typical reconstruction fidelities F >/~0.95.     

Aging phenomena in spin glasses and frustrated ferromagnets

An experimental protocol developed for spin glasses has been applied to a reentrant system. We compare the main features of the aging phenomena in both spin glass and ferromagnetic phases.     

Field emission properties of silicon field emitter arrays with volcano-shaped gate structure

Field emission properties of silicon field emitter arrays (Si-FEAs) with sputtered gate structures were described and analyzed about two different tip structures surrounded by volcano-shaped gates. The resulted field emission characteristics showed that some of the emitted electrons are diverted to the gate structure because of the asymmetrical geometry of fabricated Si-FEAs with volcano-shaped gate structures. However, although the gate structures of fabricated FEAs had fragile and non-uniform edged shapes as a result of the shadow effect during sputtering and lift-off process in ultrasonic bath, it was possible to obtain stable field emission properties as a result of electrical aging effects on the edge of the non-uniform gate electrode as well as the surface of silicon tip after repeated measurements. From the Fowler–Nordheim (F–N) plots and F–N equations, it was confirmed that the field enhancement factor was abruptly changed through the electrical aging and was more influenced in case of the volcano-shaped lateral tip structure.     

Comment on: “Efficient high-capacity quantum secret sharing with two-photon entanglement” [Phys. Lett. A 372 (2008) 1957]

In a recent Letter [F.G. Deng, X.H. Li, H.Y. Zhou, Phys. Lett. A 372 (2008) 1957], an efficient high-capacity quantum secret sharing scheme was proposed. However, in this comment, it is shown that the protocol does not complete the task of secret sharing well when the message sender uses the nonorthogonal entangled states as the quantum information carriers. Finally a feasible improvement of this quantum secret sharing protocol is proposed.     

Cryptanalysis of multiparty quantum secret sharing with collective eavesdropping-check

In the paper [S. Lin, Q.Y. Wen, S.J. Qin, F.C. Zhu, Opt. Commun. 282 (2009) 4455], Lin et al. put forward a quantum secret sharing protocol in which the collective eavesdropping-check is employed. We study the security of this protocol and find that it is insecure. Two dishonest agents may collaborate to eavesdrop (half of) Alice's secret messages without introducing any error.     

Efficient entanglement purification in quantum repeaters

We present an efficient entanglement purification protocol(EPP) with controlled-not(CNOT) gates and linear optics.With the CNOT gates,our EPP can reach a higher fidelity than the conventional one.Moreover,it does not require the fidelity of the initial mixed state to satisfy F > 1/2.If the initial state is not entangled,it still can be purified.With the linear optics,this protocol can get pure maximally entangled pairs with some probabilities.Meanwhile,it can be used to purify the entanglement between the atomic ensembles in distant locations.This protocol may be useful in long-distance quantum communication.     

Effects of hearing loss and spectral shaping on identification and neural response patterns of stop-consonant stimuli

In order to determine the effects of hearing loss and spectral shaping on a dynamic spectral speech cue, behavioral identification and neural response patterns of stop-consonant stimuli varying along the /b-d-g/ place-of-articulation continuum were measured from 11 young adults (mean age = 27 years) and 10 older adults (mean age = 55.2 years) with normal hearing, and compared to those from 10 older adults (mean age = 61.3 years) with mild-to-moderate hearing impairment. Psychometric functions and N1-P2 cortical evoked responses were obtained using consonant-vowel (CV) stimuli with frequency-independent (unshaped) amplification as well as with frequency-dependent (shaped) amplification that enhanced F2 relative to the rest of the stimulus. Results indicated that behavioral identification and neural response patterns of stop-consonant CVs were affected primarily by aging and secondarily by age-related hearing loss. Further, enhancing the audibility of the F2 transition cue with spectrally shaped amplification partially reduced the effects of age-related hearing loss on categorization ability but not neural response patterns of stop-consonant CVs. These findings suggest that aging affects excitatory and inhibitory processes and may contribute to the perceptual differences of dynamic spectral cues seen in older versus young adults. Additionally, age and age-related hearing loss may have separate influences on neural function.     

A revised controlled deterministic secure quantum communication with five-photon entangled state

A revised controlled deterministic secure quantum communication protocol using five-photon entangled state is proposed. It amends the security loopholes pointed by Qin et al. in [S.J. Qin, Q.Y. Wen, L.M. Meng, F.C. Zhu, Opt. Commun. 282 (2009) 2656] in the original protocol proposed by Xiu et al. in [X.M. Xiu, L. Dong, Y.J. Gao, F. Chi, Opt. Commun. 282 (2009) 333]. The security loopholes are solved by using order rearrangement of transmission photons and two-step security test.     

Influence of aging time of the starting solution on the physical properties of fluorine doped zinc oxide films deposited by a simplified spray pyrolysis technique

Fluorine doped zinc oxide (FZO) films were fabricated from fresh and aged (4, 8, 12 and 16 days) starting solutions using a simplified and low cost spray pyrolysis technique. The X-ray diffraction study showed that the preferential orientation is along the (0 0 2) plane for all the films irrespective of the age of the solution. The crystallite size calculated using the Scherrer’s formula is comparatively smaller only for the film prepared from the starting solution having aging time 4 days which may be due to the efficient incorporation of fluorine atoms into the ZnO lattice. This phenomenon is confirmed by the minimum resistivity value (3.14 × 10⁻² Ω cm) obtained in this particular case. The visible transmittance and the optical band gap values are found to be in the range of 63–83% and 3.20–3.31 eV, respectively. The optical transmittance is found to decrease gradually as the aging time of the solution increases and the optical band gap is found to be slightly higher in the case of the film prepared from the fourth day solution. The scanning electron microscopy results depicted that the microstructure of ZnO:F films are largely influenced by the aging of the starting solution.     

Dispersion of multi-walled carbon nanotubes in biocompatible dispersants

Owing to their phenomenal electrical and mechanical properties, carbon nanotubes (CNT) have been an area of intense research since their discovery in 1991. Different applications for these nanoparticles have been proposed, among others, in electronics and optics but also in the medical field. In parallel, emerging studies have suggested potential toxic effects of CNT while others did not, generating some conflicting outcomes. These discrepancies could be, in part, due to different suspension approaches used and to the agglomeration state of CNT in solution. In this study, we described a standardized protocol to obtain stable CNT suspensions, using two biocompatible dispersants (Pluronic F108 and hydroxypropylcellulose) and to estimate the concentration of CNT in solution. CNT appear to be greatly individualized in these two dispersants with no detection of remaining bundles or agglomerates after sonication and centrifugation. Moreover, CNT remained perfectly dispersed when added to culture medium used for in vitro cell experiments. We also showed that Pluronic F108 is a better dispersant than hydroxypropylcellulose. In conclusion, we have developed a standardized protocol using biocompatible surfactants to obtain reproducible and stable multi-walled carbon nanotubes suspensions which can be used for in vitro or in vivo toxicological studies.     

基于STM32F407的以太网通信模块设计

物联网的大规模形成和高速发展,使得基于以太网通信的嵌入式系统开发成为物联网应用的一个实际课题。本论文设计了一种以STM32F407作为主处理器的以太网通信模块;利用32位闪存微控制器STM32F407与以太网模块CH395实现串口通信;采用CH395控制芯片内置的TCP/IP协议栈与上位机LabVIEW客户端建立数据通信,并实时发送测试数据进行实验研究。实测结果表明：基于STM32F407的以太网通信嵌入式系统工作稳定,数据传输可靠,能够满足系统设计需求。     

Microscopic description of an Ising spin glass near the percolation threshold

Monte Carlo results using a microscopic model to describe FexZn(1-x)F2 indicate that its spin-glass phase at x=0.25 and zero magnetic field is characterized by the presence of antiferromagnetic fractal domains, separated by random vacancies and strongly correlated in time. The effective local random-field distribution corroborates this glassy behavior, which emerges irrespective of ab initio competing interactions and is a consequence of the fractal domain structure near the percolation threshold, x(p)=0.24. The aging properties of the system are in agreement with predictions of short-range stochastic spin-glass models and with the droplets model for spin glass close to percolation.     

An improved quantum key distribution protocol based on second-order coherence

We improve the quantum key distribution protocol proposed by Pereira et al. [S.F. Pereira, Z.Y. Ou, H.J. Kimble, Phys. Rev. A 62 (2000) 042311], by employing the second-order coherence of optical fields, which can be easy experimentally measured with a Hanbury-Brown and Twiss intensity interferometer. It is shown that eavesdropping can be directly detected without sacrificing extra secret bits as test key. The efficiency of the improved system is enhanced greatly, since no secret bit needs to be discarded.     

Aging Thyroarytenoid and Limb Skeletal Muscle: Lessons in Contrast

Voice production is vital throughout life because it allows for the communication of basic needs as well as the pursuit and enjoyment of social encounters. Unfortunately, for many older individuals the ability to produce voice is altered. Structural and functional declines in the neuromuscular system occur with aging and likely contribute to the modification of voice. One specific target of the aging process is the thyroarytenoid (TA) muscle, the primary muscle of voice production. The objectives of this overview article are to (1) share current findings related to the aging of limb skeletal muscle, (2) identify age-related morphological and physiological features of TA muscle, (3) compare and contrast age-related changes in TA with those in limb skeletal muscle, and (4) describe therapies for reversing sarcopenia in limb muscle and consider the applicability of these therapies for addressing vocal fold atrophy and age-related voice changes. The article shares current knowledge from the basic sciences related to skeletal muscle aging and compares/contrasts typical muscle aging to TA aging. Current evidence suggests that (1) the TA muscle undergoes notable remodeling with age, (2) aging of the TA is multifactorial, resulting from a myriad of neurologic, metabolic, and hormonal changes, many of which are distinct from the age-related processes of typical limb skeletal muscle, (3) investigation of the aging of the TA and its role in the aging of voice is in its infancy, and (4) potential behavioral and nonbehavioral therapies for reversing aging of the TA must be further examined.     

一种尼龙老化评价的新方法

作为一种广泛使用的工程塑料,尼龙的老化备受关注。当作为电力系统芯片的封装材料时,尼龙在自然环境下的老化有可能会导致封装失效,从而影响芯片使用的可靠性,严重时甚至导致芯片的失效,给电力行业带来巨大损失。常规的自然老化和人工加速老化评价周期非常漫长,不同因素对尼龙老化的影响机理十分复杂,且这种影响难以研究,使得评价尼龙的老化稳定性成为一大难题。采用自主开发的原位老化评价系统,对尼龙6（PA6）和尼龙66（PA66）的老化稳定性及湿度对老化的影响进行了研究。该系统可以实现光照/温度/湿度/氧气等环境因素的加载,通过高灵敏度地测定材料在综合环境因素作用下产生的气相降解产物来评价材料的老化稳定性,评价时间缩短到几小时。实验表明,PA6和PA66的气相降解产物以H₂O和CO₂为主,由于H₂O在气相中的浓度不稳定,因此以CO₂的产生量作为老化评价指标。通过对不同自然老化时间PA6和PA66的原位老化评价,并与其ATR-FTIR红外光谱图进行对照,证明了原位老化评价方法能够较好地反映尼龙的老化程度,自然老化时间越长,PA6和PA66的稳定性越低,CO₂的产生量越大。进一步,采用该方法研究了湿度对PA6和PA66老化反应的影响,证明增大湿度对尼龙老化存在促进作用,而且升高温度会进一步促进湿度对老化的促进作用。研究表明,原位老化评价方法是一种快速评价尼龙老化稳定性及环境因素影响的有力手段。     

基于分组交换的量子通信网络传输协议及性能分析

量子纠缠交换能够建立可靠的量子远程传输信道, 实现量子态的远程传输. 然而, 基于纠缠交换的量子信道要求网络高度稳定, 否则会浪费大量纠缠资源. 为节省纠缠资源, 本文根据隐形传态理论, 提出了一种基于分组交换的量子通信网络传输协议, 建立了发送量子态所需的纠缠数目与所经过的路由器数、链路错误率的定量关系, 并与纠缠交换传输协议进行了比较. 仿真结果表明, 在链路错误率为0.1% 时, 分组传输协议所使用的纠缠数目少于纠缠交换的数目, 另外, 随着错误率的升高, 分组传输协议所需的纠缠数比纠缠交换协议明显减少. 由此可见, 基于分组交换的量子通信网络传输协议在网络不稳定时, 能够节省大量纠缠资源, 适用于链路不稳定的量子通信网络.     

放射性污染物粘膜铺设车控制系统设计

放射性污染物粘膜铺设车是核事故应急的一种主要装备。为解决放射性污染物粘膜铺设车多工位实时操控需要,设计了由主控屏、辅控屏和手持终端三种控制终端共同组成上位机的控制系统。该系统以主控屏作为交互中心,通过标准RS232接口与下位机通信;辅控屏和手持终端作为主控屏外设,分别通过CET-5E网线和蓝牙将数据实时传输至主控屏,实现不同工位下的可靠操控。下位机主控制器以ARM7作为主处理器,采用Modbus通信协议与上位机通信,便于系统后续拓展开发。实验表明,该多终端操控系统不受辐射环境干扰,通信稳定,操作便捷,实时性高,符合粘膜铺设车作业工况要求。这种通过主屏地址映射实现多终端控制的方式,有利于降低主控制器仲裁压力、减少数据冗余、提高系统时效,适合在各种特种车辆的控制系统中推广应用。     

Vocal violence in actors: An investigation into its acoustic consequences and the effects of hygienic laryngeal release training

Acoustic analysis techniques were used to investigate the short-term consequences of vocally violent behavior, and to compare voice production before and after training in hygienic laryngeal release (HLR) techniques. Twenty-seven actors ranging in age from 17 to 48 years were audiorecorded before and after multiple productions of 4 vocally violent behaviors: grunting, groaning, sobbing, and shouting. After training in HLR techniques, the experimental protocol was repeated. Audiorecordings of vowels (produced at 3 pitch levels: modal F0, minimum F0, maximum F0) before and after vocal violence, and before and after HLR training, were analyzed using the Multidimensional Voice Program (4305, Kay Elemetrics Corp, Lincoln Park, NJ). After vocal violence, no consistent acoustic changes were detected for voice generated at modal and minimum F0; however, significant increases in both fundamental frequency range and maximum F0 were observed. After training in HLR techniques, acoustic measures sensitive to pitch and amplitude perturbation, and non-harmonic noise, improved across pitch levels. The results also indicated that vocal training does defend the laryngeal system from undesirable changes related to vocally violent maneuvers that might surface at the extremes of an actor's pitch range. Because the HLR technique used in this investigation was multimodal, interesting questions are raised regarding which aspect of training is primarily responsible for the observed effects. Further study is required to identify such factors.