Developing electric bus driving cycles with significant road gradient changes::A case study in Hong Kong

Battery electric buses have been increasingly being deployed to replace traditional diesel buses in providing urban public transport services. Accounted for over 30% of daily passenger trips, the franchised bus system in Hong Kong only retained a few battery electric buses after its trial programme. Under the unique bus driving environment in Hong Kong, more evaluations are anticipated for further deployment of electric buses. Driving cycle is a widely adopted platform for the assessment of vehicle fuel economy, energy consumption, emissions and driving range. Therefore, it is necessary to have a purposely developed driving cycle for battery electric buses. A comprehensive review of bus driving cycles developed elsewhere shows that the impacts of road gradients are seldom considered. Therefore, in this study, the only remaining battery electric bus route with significant gradient changes was selected for speed data collection and synthesis for a set of driving cycles. Results shown that driving characteristics of this route were comparable to urban bus cycles developed in other cities, but were slightly different from bus cycles developed for other conditions. It was also observed that battery electric buses appeared to be less responsive to drivers’ acceleration activities than that of a supercapacitor bus

A bottom-up clustering approach to identify bus driving patterns and to develop bus driving cycles for Hong Kong

Bus transport has been an important mode taking up a significant share of urban travel demand and thus the corresponding impacts on the environment are of great concerns. Use of driving cycles to evaluate the environmental impacts of buses has attracted much attention in recent years worldwide. The franchised bus service is currently playing important roles in the public transport system in Hong Kong; however, there is no driving cycle developed specifically for them. A set of bus driving cycle was therefore developed using a bottom-up approach where driving data on the bus network with mixed characteristics were collected. Using the Ward’s method for clustering, the collected data were then categorized into three clusters representing distinct franchised bus route patterns in Hong Kong. Driving cycles were then developed for each route pattern including (i) congested urban routes with closely spaced bus stops and traffic junctions; (ii) inter-district routes containing a number of stop-and-go activities and a significant portion of smoother high speed driving; and (iii) early morning express routes and mid-night routes connecting remote residential areas and urban areas. These cycles highlighted the unique low-speed and aggressive driving characteristics of bus transport in Hong Kong with frequent stop-and-go activities. The findings from this study would definitely be helpful in assessing the exhaust emissions, fuel consumptions as well as energy consumptions of bus transport. The bottom-up clustering approach adopted in this study would also be useful in identifying specific driving patterns based on vehicle speed trip data with mixed driving characteristics. It is believed that this approach is especially suitable for assessing fixed route public transport modes with mixed driving characteristics

Meta-analysis Followed by Replication Identifies Loci in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as Associated with Systemic Lupus Erythematosus in Asians

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic involvement and ethnic differences. Susceptibility genes identified so far only explain a small portion of the genetic heritability of SLE, suggesting that many more loci are yet to be uncovered for this disease. In this study, we performed a meta-analysis of genome-wide association studies on SLE in Chinese Han populations and followed up the findings by replication in four additional Asian cohorts with a total of 5,365 cases and 10,054 corresponding controls. We identified genetic variants in or near CDKN1B, TET3, CD80, DRAM1, and ARID5B as associated with the disease. These findings point to potential roles of cell-cycle regulation, autophagy, and DNA demethylation in SLE pathogenesis. For the region involving TET3 and that involving CDKN1B, multiple independent SNPs were identified, highlighting a phenomenon that might partially explain the missing heritability of complex diseases

Development of bus driving cycles using a cost effective data collection approach

Driving cycles are important for vehicle performance evaluations including emissions and fuel/energy consumption estimations. The franchised bus services are currently being extensively used in Hong Kong, however, no driving cycle has been developed specifically for buses. Therefore, this study has developed a set of bus driving cycles using a cost effective data collection approach. On-road bus speed data were collected using the built-in GPS function of smartphones Based on an analysis of the structure of the franchised bus route network and the statistical properties of the collected bus speed data, five significantly different bus driving patterns in Hong Kong were identified. Separate driving cycles were then developed for each identified pattern namely Pattern I(a): Inter-districts; Pattern I(b): Within a District; Pattern II(a): Peaks; Pattern II(b) Off Peak (Day); and Pattern II(c): Off Peak (Night). These patterns indicated significantly longer idling and more aggressive acceleration/deceleration characteristics as compared to other international bus driving cycles. Bus operators and regulating authorities can select appropriate cycles for traditional/electric bus emission and/or energy consumption estimations under specific bus driving patterns. The developed cycles can also fill the knowledge gap in providing a representative platform for the bus emissions testing in Hong Kong

Chromatographic profiling and multivariate analysis for screening and quantifying the contributions from individual components to the bioactive signature in natural products

A new approach for assigning bioactivity to individual components in extracts from natural products is presented and validated. 60 mixtures were created according to a uniform design from 12 chemical components of which 7 possessed antioxidant activity. The synthetic mixtures were characterized by chromatographic profiling and their antioxidant power was assessed by use of the Ferric Reducing Antioxidant Power (FRAP) assay. 40 of the prepared mixtures were used as a training set to create a cross validated partial least squares (PLS) regression model with the FRAP measurement as response. The remaining 20 mixtures were used as an independent external validation set. The bioactive signature was singled out from the multi-component PLS model using target projection (TP). In addition to excellent prediction performance of antioxidant strength from the bioactive signature, our approach, called Quantitative Pattern-Activity Relationship (QPAR), was able to rank 6 of the 7 bioactive components according to individual bioactive strength. The ratios of bioactive capacity of the two most active components to the two least active components were close to 100 to 1. This explains why one of the two least bioactive components was not detected

Three SNPs in chromosome 11q23.3 are independently associated with systemic lupus erythematosus in Asians

Systemic lupus erythematosus (SLE) has a complex etiology and is affected by both genetic and environmental factors. Althoughmorethan 40 loci haveshownrobust association withSLE, the details of these loci,suchas the independent contributors and the genes involved, are still unclear. In this study, we performed meta-analysis of two existing genome-wide association studies (GWASs) on Chinese Han populations from Hong Kong and Anhui, China, and followed the findings by further replication on three additional Chinese and Thailand cohorts with a total of 4254 cases and 6262 controls matched geographically and ethnically. We discovered multiple susceptibility variants for SLE in the 11q23.3 region, including variants in/near PHLDB1 (rs11603023, P_combined 5 1.25E208, OR 5 1.20), DDX6 (rs638893, P_combined 5 5.19E207, OR 5 1.22) and CXCR5 (rs10892301, P_combined 5 2.51E208, OR 5 0.85). Genetic contributions from the newly identified variants were all independent of SNP rs4639966, whose association was reported from the previous GWAS. In addition, the three newly identified variants all showed independent association with the disease through modeling by both stepwise and conditional logistic regression. The presence of multiple independent variants in this region emphasizes its role in SLE susceptibility, and also hints the possibility that distinct biological mechanisms might be involved in the disease involving this genomic region. © The Author 2013. Published by Oxford University Press. All rights reserved.Link_to_subscribed_fulltex