An overview of antimicrobial properties of kombucha

Kombucha is a traditional beverage of Manchurian origin, typically made by fermenting sugared black or green tea with the symbiotic consortium of bacteria and yeast (SCOBY). The beverage has gained increasing popularity in recent years, mainly due to its heralded health benefits. The fermentation process of kombucha also results in the production of various bioactive compounds with antimicrobial potential, making it a promising candidate in the exploration of alternative sources of antimicrobial agents, and may be helpful in combating the rising threat of antibiotic resistance. Literature survey performed on Web of Science, Scopus, and PubMed revealed the extensive research that has firmly established the antimicrobial activity of kombucha against a broad spectrum of bacteria and fungi. This activity could be attributed to the synergistic activities of the microbial species in the kombucha microbiota that led to the synthesis of compounds with antimicrobial properties such as acetic acid and various polyphenols. However, research thus far only involved screening for the antimicrobial activity of kombucha. Therefore, there is still a research gap about the molecular mechanism of the kombucha reaction against specific pathogens and its influence on human health upon consumption. Future research may focus on investigating this aspect. Further characterization of the biological activity of the microbial community in kombucha may also facilitate the discovery of novel antimicrobial compounds, such as bacteriocins produced by the microorganisms.     

粗粒土中预制桩的静压施工残余应力

预制桩 沉桩施工阶段形成的桩身残余应力对桩的工作性状有重要影响。原位观测了两根 H 型钢桩静力压入粗粒土地基过程中的桩身应力,测得了很大的桩身与桩端施工残余应力。施工残余摩阻力之中性点深度随贯入桩长增加而下移,但两者之比值趋于定值。桩端残余应力除了与弹性系数有关,还受到压桩力与贯入速率的影响。随着压桩荷载循环次数的增长,残余负摩阻力不断累积,但某一固定土层深度的单位残余负摩阻力却呈现下降趋势,这与沉桩侧摩阻力的疲劳退化机理是一致的。施工残余应力的存在改变了桩周土与桩端土的初始应力状态,使得桩–土体系在工作条件下会沿着与预期不一致的应力路径受荷至破坏。这对传统的静载荷试验和 Osterberg 试桩的成果分析方法提出了挑战。若考虑施工残余应力,对桩的抗拔承载性状有利,并使得开口管桩土塞效应问题变得更复杂。桩身残余应力的分布可基于残余摩阻力的折线型分布假定,利用桩端残余应力来预测。     

Sevoflurane Induces Neurotoxicity in the Animal Model with Alzheimer’s Disease Neuropathology via Modulating Glutamate Transporter and Neuronal Apoptosis

Perioperative neurocognitive disorders are frequently observed in postoperative patients and previous reports have shown that pre-existing mild cognitive impairment with accumulated neuropathology may be a risk factor. Sevoflurane is a general anesthetic agent which is commonly used in clinical practice. However, the effects of sevoflurane in postoperative subjects are still controversial, as both neurotoxic or neuroprotective effects were reported. The purpose of this study is to investigate the effects of sevoflurane in 3 × Tg mice, a specific animal model with pre-existing Alzheimer’s disease neuropathology. 3 × Tg mice and wild-type mice were exposed to 2 h of sevoflurane respectively. Cognitive function, glutamate transporter expression, MAPK kinase pathways, and neuronal apoptosis were accessed on day 7 post-exposure. Our findings indicate that sevoflurane-induced cognitive deterioration in 3 × Tg mice, which was accompanied with the modulation of glutamate transporter, MAPK signaling, and neuronal apoptosis in the cortical and hippocampal regions. Meanwhile, no significant impact was observed in wild-type mice. Our results demonstrated that prolonged inhaled sevoflurane results in the exacerbation of neuronal and cognitive dysfunction which depends on the neuropathology background.     

An Efficient Mode Decision Algorithm for H.264/AVC Encoding Optimization

The H.264 video coding standard significantly outperforms previous standards in terms of coding efficiency. However, this comes as a cost of extremely high computational complexity due to mode decision where variable block size motion estimation (ME) is employed. In this paper, we propose an efficient algorithm to jointly optimize mode decision and ME. A theoretical analysis is performed to study the sufficient condition to detect all-zero blocks in H.264, and thus adaptive thresholds are derived to early terminate mode decision and ME. Besides the aforementioned early termination technique, the proposed algorithm also introduces temporal-spatial checking, thresholds based prediction and monotonic error surface based prediction methods to skip checking unnecessary modes. Experimental results demonstrate that the proposed algorithm can significantly reduce the computational complexity of H.264 encoding while maintaining almost the same rate distortion (RD) performance as the original encoder     

Field lines in the Mandelbrot set

A technique for displaying color images of field lines surrounding the Mandelbrot Set using angle-slicing decomposition and a “contrast color lookup table,” is described. A modification of this method, which compensates for the spatial-frequency doubling inherent in angle-slicing decomposition, can produce black and white images that even more accurately portray the field lines.     

High performance red and green phosphorescent emitters suitable for the BT.2020 color gamut

In this work, we investigated the potential for phosphorescent emitters to achieve the BT.2020 color standard in displays, where the CIE coordinates for red and green are (0.709, 0.292) and (0.170, 0.797), respectively. Optical simulations were performed for both green and red top emission organic light emitting devices (OLEDs). For the green emitter, it is possible to reach (0.170, 0.785) using a spectrum with a peak wavelength (λ_max) at 526 nm and a full width at half maximum (FWHM) less than 30 nm. For the red emitter, in order to achieve (0.708, 0.292) while maintaining a high current efficiency (CE), it is important to decrease the FWHM instead of red-shifting the spectrum. Following the guidance of these simulation results, we designed and synthesized novel deep green (DGD) and deep red phosphorescent (DRD-II) emitters. The photoluminescent (PL) spectrum of DGD shows an FWHM of 30 nm and a λ_max of 523 nm. A top-emission green OLED built using DGD reached a CE of 171 cd/A at an operating voltage of 3.3 V and a lifetime of 95% of initial brightness (LT₉₅) > 1300 h at 10 mA/cm² with a CIE (x, y) = (0.170, 0.777). This is, to our knowledge, the best device performance ever reported for a green phosphorescent OLED at this CIE y. The PL spectrum of DRD-II has a λ_max of 630 nm with an FWHM of 30 nm. A top-emission red OLED built with DRD-II achieved a CE of 59 cd/A, an operating voltage of 3.2 V and an LT₉₅ over 20,000 h at a drive current of 10 mA/cm² with a CIE (x, y) = (0.708, 0.292). We also studied the angular dependence of the above devices and found they were comparable to devices with commercial emitters for the Digital Cinema Initiative P3 (DCI-P3) standard that had a wider FWHM. Combining these green and red emitters with a commercial blue OLED at (0.131, 0.046), we are able to cover 97% of the BT.2020 color gamut. The results using DGD and DRD-II suggest that they have great potential to satisfy BT.2020 in an organic phosphorescent system.     

An adaptive parallel genetic algorithm system for i‐Computing environment

Many real‐world optimization problems in the scientific and engineering fields can be solved by genetic algorithms (GAs) but it still requires a long execution time for complex problems. At the same time, there are many under‐utilized workstations on the Internet. In this paper, we present a self‐adaptive parallel GA system named APGAIN, which utilizes the spare power of the heterogeneous workstations on the Internet to solve complex optimization problems. In order to maintain a balance between exploitation and exploration, we have devised a novel probabilistic rule‐driven adaptive model (PRDAM) to adapt the GA parameters automatically. APGAIN is implemented on an Internet Computing system called DJM. In the implementation, we discover that DJM's original load balancing strategy is insufficient. Hence the strategy is extended with the job migration capability. The performance of the system is evaluated by solving the traveling salesman problem with data from a public database. Copyright © 2003 John Wiley & Sons, Ltd.