Asymmetric magnetization splitting in diamond domain structure: Dependence on exchange interaction and anisotropy

The distributions of magnetization orientation for both Landau and diamond domain structures in nano-rectangles have been investigated by micromagnetic simulation with various exchange coefficient and anisotropy constant. Both symmetric and asymmetric magnetization splitting are found in diamond domain structure, as well as only symmetric magnetization splitting in Landau structure. In the Landau structure, the splitting angle increases with the exchange coefficient but decreases slightly with the anisotropy constant, suggesting that the exchange interaction mainly contributes to the magnetization splitting in Landau structure. However in the diamond structure, the splitting angle increases with the anisotropy constant but derceases with the exchange coefficient, indicating that the magnetization splitting in diamond structure is resulted from magnetic anisotropy.Comment: 5 pages, 5 figure

Optimization of medium composition for cisepoxysuccinate hydrolase production in Escherichia coli by response surface methodology

Response surface methodology was applied to identify and optimize the medium composition for the cis-epoxysuccinate hydrolase production in recombinant Escherichia coli. Plackett-Burman design was used in the first step to evaluate the effects of 8 variables on the enzyme activity. CaCl2, corn steep liquor and lactose were screened as significant factors and their concentrations were further optimized using response surface methodology based on 23 full factorial rotatable central composite design. The optimum predicted medium for maximum expression of recombinant  cis-epoxysuccinate hydrolase was found to comprise: 17.1 g/l Na2HPO4·12H2O, 2.0 g/l KH2PO4, 0.5 g/l NaCl, 1.0 g/l NH4Cl, 0.0111 g/l CaCl2 and 0.5 g/l MgSO4·7H2O, 17.18 ml/l corn steep liquor and 9.74 g/l lactose, with a predicted enzyme activity of 35490 U/g biomass, which was very close to the experimental activity of 36318 U/g biomass resulting in 1.7-fold increment after optimization

Research progress on the acoustic environments of healthy buildings / 健康建筑声环境研究进展

Building and urban acoustic environments greatly contribute to the quality of healthy buildings. This paper first discusses the developmental transitions from noise control to soundscape construction, and the changing focus from negative effects on public health to the promotion of health benefits. During this transition, the impacts of acoustic environments on human health have been investigated from various research perspectives, from concept to theory to methods. In current soundscape research, sound environment designs are based on health concepts. Innovative results have been introduced from this focus. First, the impacts of soundscape perception on human health and the psychophysiological effects of soundscape have been extensively reviewed. Reduced negative soundscapes are significantly positively correlated with the self-reported health conditions of subjects. Especially, soundscapes reported as positive (e.g., pleasant and calm) are significantly positively correlated with environmental stress restoration. The physiology and neurophysiology of soundscapes are emerging subjects that require extensive further research. Research on the restorative effects of urban public open spaces has included the development of relevant theories and practice, experimental studies of restorative performance and its influencing factors, and sensitivity studies, which measure the response magnitude of physiological indicators to typical soundscapes. The restorative quality of public open spaces in the urban context is of particular interests. Soundscapes in public open spaces are known to directly affect the psychology, physiology, and attention span of individuals. They also exert an indirect recovery effect through audio-visual interactions. A study on the sensitivity study of physiological indicators analyzed the change of the physiological signals over time, the type of scenery, and the restoration effect was quantified from the relationships among different subjective scales. Stressed children exposed to different potentially restorative soundscapes perceive the restorative sound scenery differently from adults. The effect of noise on the cognitive performance of children is primarily reflected in the degree of subjective annoyance, and children's test performances do not significantly depend on the varying noise conditions. In specific spaces such as hospitals, the acoustic environment is known to affect inpatient health and the efficiency of hospital staff. Studies have confirmed that improving the acoustic environment benefits the resting ability, sleep, and mood of inpatients, and this can also improve the efficiency of hospital staff. With the broadening and deepening of acoustic environment research and the effective development of research tools, indicator systems and research paradigms will become more standardized. Such standardization will further deepen the research and lead to evaluative standards. Much scope remains for investigating the impact mechanism and efficiency of various soundscape restorative treatments in urban public open spaces. Furthermore, the health effects of soundscape treatments for other specific groups of people and other specific spaces should be elucidated. Finally, research should move from revealing the influence patterns and tendencies of soundscapes toward the active design of healthy acoustic environments. / 建筑及城市声环境是健康建筑质量的重要组成部分. 本文首先讨论了从噪声控制到声景营造, 即从降低负 面健康影响到促进公众健康的发展趋势, 在这个从观念到理论到方法的转化过程中, 声环境对人的健康影响有了 更为科学的研究视角和操作方法, 与基于健康理念的声环境设计共同成为声景研究持续关注的焦点. 在此基础上, 介绍了一些近期的创新研究成果, 包括声景感知对健康效应的影响, 及声景的心理生理学方面的系统性综述研究; 基于恢复性环境理论的城市公共开放空间声景恢复性效应的理论发展和实证研究进展、典型声景的生理指标变 化的敏感性研究; 针对特定群体健康影响的研究, 包括儿童恢复性声景研究、环境噪声对儿童认知能力的影响研 究; 针对特定空间的声环境健康研究, 包括医院声环境对住院病人健康、对医护人员工作效率的影响等. 总体而言, 声景的生理学和神经生理学研究尚处于起步阶段, 有许多方面值得研究; 城市公共开放空间声景恢复性效应, 其影 响机理和主动调节层面还有值得深入研究的内容; 针对特定人群和特定空间的声景健康研究还将拓展到其他人群 和空间, 研究也将从客观影响规律走向基于健康的声环境主动设

Mandarin Chinese translation of the ISO-12913 soundscape attributes to investigate the mechanism of soundscape perception in urban open spaces

This study is part of a global collaboration to translate the soundscape attributes proposed in ISO/TS 12913-2:2018, which aims to standardise soundscape research globally. Cross-referencing results from two independent expert panels produced a set of eight soundscape attributes that were subsequently experimentally verified, forming a reliable questionnaire for soundscape characterisation in Mandarin Chinese. Employing the as-developed questionnaire, ex situ auditory-only soundscape perception experiments were carried out with 27 soundscape recordings from urban open spaces in the United Kingdom. The soundscape perception scale was used to evaluate participants' experiences, which were then projected into two dimensions of soundscape perception, pleasantness and eventfulness, following protocols from ISO 12913-3:2019. Physical and psychoacoustic parameters, as well as the characteristics of the sound sources, were extracted from the recordings. These parameters were used together to describe the soundscape characteristics of the recordings. Principal component analysis revealed that, when individuals are exposed to urban open spaces, the salient sound source becomes the foreground focus of attention, informing them to perceive the soundscape. Beyond this, perception stimulation is further based on the acoustic characteristics of the soundscape. Regression analysis investigated factors for pleasantness and eventfulness. For pleasantness, the overall S95 had a significant negative effect while birdsong was beneficial. With regard to eventfulness, mechanical sound had a detrimental impact, while the number of salient sound source types and the overall F50 had a positive impact. Furthermore, this study founds that certain types of sound sources make the sound more recognisable as a foreground sound, thereby stimulating perception, while others may be ignored as background sounds but still contribute to the perception through their acoustic characteristics

Delayed implantation of a peripheral nerve graft reduces motoneuron survival but does not affect regeneration following spinal root avulsion in adult rats

Adult spinal motoneurons can regenerate their axons into a peripheral nerve (PN) graft following root avulsion injury if the graft is implanted immediately after the lesion is induced. The present study was designed to determine how avulsed motoneurons respond to a PN graft if implantation takes place a few days to a few weeks later. Survival, regeneration, and gene expression changes of injured motoneurons after delayed PN graft implantation were studied. The survival rates of spinal motoneurons were 78%, 65%, 57%, or 53% if a PN graft was implanted immediately, 1, 2, or 3 weeks after root avulsion, respectively. Interestingly, most of the surviving motoneurons were able to regenerate their axons into the graft regardless of the delay. All regenerating motoneurons expressed p75, but not nNOS, while all motoneurons that failed to regenerate expressed nNOS, but not p75. p75 and nNOS may, therefore, be used as markers for success or failure to regenerate axons. In the group with immediate graft implantation, 85% of the surviving motoneurons extended axons into the PN graft, while in the groups in which implantation was delayed 1, 2, or 3 weeks, 84%, 82%, and 83% of the surviving motoneurons, respectively, were found to have regenerated into the grafts. These findings indicate that avulsed spinal motoneurons retain the ability to regenerate for at least 3 weeks, and perhaps for as long as they survive. Therefore, the delayed implantation of a PN graft after root avulsion may provide a continued conducive environment to support regeneration.published_or_final_versio

Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide

We report that Bi$_2$Se$_3$ thin films can be epitaxially grown on SrTiO$_{3}$ substrates, which allow for very large tunablity in carrier density with a back-gate. The observed low field magnetoconductivity due to weak anti-localization (WAL) has a very weak gate-voltage dependence unless the electron density is reduced to very low values. Such a transition in WAL is correlated with unusual changes in longitudinal and Hall resistivities. Our results suggest much suppressed bulk conductivity at large negative gate-voltages and a possible role of surface states in the WAL phenomena. This work may pave a way for realizing three-dimensional topological insulators at ambient conditions.Comment: 5 pages, 4 figures

Temperature oscillation of a dual compensation chamber loop heat pipe under acceleration conditions

Loop heat pipe has a wide application in the fields of airborne electronics cooling and thermal management. However, the pertinent temperature oscillation of the loop heat pipe could lead to adverse effects on the electronics. In the current study, an ammonia-stainless steel dual compensation chamber loop heat pipe was developed to experimentally investigate the temperature oscillation under different acceleration conditions. The impact of several control parameters such as different heat loads, loading modes, acceleration directions and magnitudes on the operational performance of the loop heat pipe was analyzed in a systematic manner. The heat load applied on the evaporator ranged from 25 W to 300 W. The acceleration magnitude varied from 1 g to 9 g and four different acceleration direction, i.e. configurations A, B, C and D, were taken into account. Two different loading modes were applied with different heat load and acceleration force. Experimental results show that (i) the loop temperature will change and oscillate as the acceleration force was applied under all test conditions. It can be easily found that the temperature oscillation occurred at both heat loads of 250 W and 300 W. (ii) for the case of the first loading mode, periodic temperature oscillation is observed on the liquid line, whereas for the second loading mode, periodic temperature oscillation can be easily appeared on the entire loop. (iii) the loop temperature under both configurations A and B with acceleration of 7 g does not oscillate at heat load of 150 W, 200 W and 250 W when the first loading mode is applied. Especially under configuration B, the acceleration could contribute to repress the temperature oscillation. Under the current heat loads for almost all cases, the temperature oscillation can be observed for configurations A, C and D with acceleration of 5 g. (iv) the amplitude of evaporator at heat load of 300 W under configuration C are 0.6 °C, 0.3 °C, 0.2 °C and 0.3 °C with acceleration of 3 g, 5 g, 7 g and 9 g. The corresponding period is 66 s, 36 s, 34 s and 36 s, respectively