No abstract

Folates belong to the essential B vitamins group and participate in one-carbon metabolism. Date palm fruits (Phoenix dactilyfera L. family Arecaceae) are consumed by millions of people and are good sources of folates. To date, no detailed study has been carried out on suitable methods for folate extraction from date palm fruits. In the present study, an experimental design using response surface methodology (RSM) was used to maximize the extraction yield of folates from date palm fruits by including enzymatic depectinization. By applying this new strategy and a UHPLC-MS/MS technique for analysis, total folate and different folate vitamers of three cultivars of date palm fruits (Muzafti, Zahdi, and Rubai), brewer's yeast, and fermented date wine were analyzed. The optimized extraction conditions of folates from date palm fruits were found to be a pectinase activity of 47.7 U, an incubation temperature of 40°C, and an incubation time of 38 min, which yielded a total folate content of 191–301 μg/100 g. In brewer's yeast, the extracted total folate content was very high (4,870 μg/100 g), and, in the resulting date wine, it reached a maximum of 700 μg/L on the fifth day. The predominant folate vitamers in date fruit and fruit wine were 5-formyltetrahydrofolate (5-CHO-THF) and 5-methyltetrahydrofolate (5-CH3-THF). During date palm fruit fermentation for up to 8 days, the 5-CHO-THF content gradually decreased by 20%, while 5-CH3-THF increased linearly from day 1 to day 5 (y = 0.058 x + 0.0284, R2 = 0.9614). This study shows that date palm fruit and fruit wine are excellent sources of folate, and further study can be focused on different methods to improve folate stability during wine storage.

In some scenarios such as catastrophes and military operations, there is a need for communication without an infrastructure. In urgent cases, in-time and reliable channel access must be ensured. However, the channel access delay in widely used CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) network increases unpredictably when the channel is sensed busy. Therefore, TDMA (Time Division Multiple Access) gets more and more attention in mobile ad-hoc network research. This paper presents a TDMA network system (named as P-TDMA-SYS) that is designed to support real-time applications in mobile ad-hoc networks (MANETs) and successfully works on commodity 802.11 hardware. The key feature of P-TDMA-SYS is its microsecond synchronization and adaptive medium access policy. P-TDMA-SYS's implementation contains two major modules. One is the P-KER-MAC, a TDMA-based MAC protocol, running over commodity 802.11 hardware. The other is P-TCP, a cross-layer TCP congestion control algorithm specifically for P-KER-MAC. The presented TDMA-based MAC over commodity 802.11 hardware has been tested with a detailed accounting of the hardware and operation system overheads. Furthermore, P-TDMA-SYS has been compared with 802.11 CSMA/CA-based network in the single-hop/multi-hop scenarios. The test results show that our implementation achieves reliable throughput and low delay/jitter for supporting real-time applications.

Pavement marking in daylight with poor quality cannot provide a reference for drivers to specify their own position relative to nearby vehicles. Luminance and Correlated color temperature (CCT) of sunlight is of importance for daytime visibility of in-service pavement markings, which lacks detailed consideration. This paper aims to explore the daytime visibility requirements of in-service pavement markings considering the influence of natural light characteristics. Based on analyzing the mechanism and impact factors of daytime visibility of pavement markings, a subjective scale of pavement markings state in the drivers’ field of view was proposed and a short and bold line was recommended as the standard state. Thirty-six tested drivers were randomly selected to detect white and yellow markings of both 15 cm and 20 cm width under 2000 to 23,000 lx and 5500 to 8500 K for outdoor natural light environment. The luminance contrast of the pavement marking to the surrounding road surface ranged from 0 to 10. The result indicated that the natural light with 2000 to 3000 lx and 7500 to 8500 K is the most unfavorable light environment for drivers to recognize pavement markings during daytime. The detection distance is becoming longer with the increase of luminance contrast. The detection distance does not increase with the increase of luminance contrast when the luminance contrast of white markings is greater than 4 and that of yellow markings is greater than 3. The model was established expressing the relationship between luminance contrast and Qd contrast. The preview time 3.65 s was selected to calculate the minimum requirements of Qd at speeds of 60, 80, 100 km/h, respectively, for different types of markings. The results can provide scientific evidence for quality evaluation and maintenance management of pavement markings in service for daytime visibility.

In terms of the design of SCDCS (Safety Critical Distributed Control System), MATI (Maximum AllowableTransfer Interval) is one of the important design reference parameters that influences message transmission period and network scheduling strategy. To obtain its upper bound, Lyapunov theory and matrix measure are applied to analyze SCDCS which is networked only in its feedback path, and a sufficient condition is induced which can guarantee that the SCDCS is asymptotically stable. Furthermore, an explicit and simple method of obtaining MATI for SCDCS is derived on the base of that stable condition. The simulation validates the method and shows that the method is much less conservative than the existing methods. Index Terms -safety critical DCS, maximum allowable transfer interval, asymptotically stable