Evaluation of management strategies for the operation of high-speed railways in China

High-Speed Train (HST) operations have recently been introduced in rail passenger transportation markets worldwide. Although the technologies for such operations have levelled at speeds of around 300 km/h, the operating parameters to be adopted in each application will differ from country to country. The operating environment will be one of the crucial success factors for the implementation of HST operations in China. This paper compares three different management/ownership models which might be used in China. The paper analyzes the characteristics of each model and proposes an optimal plan of an operational system to develop HST operations in China by using a hierarchy goals achievement matrix approach

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Targeted gene sanger sequencing should remain the first-tier genetic test for children suspected to have the five common X-linked inborn errors of immunity

DATA AVAILABILITY STATEMENT : The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.To address inborn errors of immunity (IEI) which were underdiagnosed in resource-limited regions, our centre developed and offered free genetic testing for the most common IEI by Sanger sequencing (SS) since 2001. With the establishment of The Asian Primary Immunodeficiency (APID) Network in 2009, the awareness and definitive diagnosis of IEI were further improved with collaboration among centres caring for IEI patients from East and Southeast Asia. We also started to use whole exome sequencing (WES) for undiagnosed cases and further extended our collaboration with centres from South Asia and Africa. With the increased use of Next Generation Sequencing (NGS), we have shifted our diagnostic practice from SS to WES. However, SS was still one of the key diagnostic tools for IEI for the past two decades. Our centre has performed 2,024 IEI SS genetic tests, with in-house protocol designed specifically for 84 genes, in 1,376 patients with 744 identified to have disease-causing mutations (54.1%). The high diagnostic rate after just one round of targeted gene SS for each of the 5 common IEI (X-linked agammaglobulinemia (XLA) 77.4%, Wiskott–Aldrich syndrome (WAS) 69.2%, X-linked chronic granulomatous disease (XCGD) 59.5%, X-linked severe combined immunodeficiency (XSCID) 51.1%, and X-linked hyper-IgM syndrome (HIGM1) 58.1%) demonstrated targeted gene SS should remain the first-tier genetic test for the 5 common X-linked IEI.The Hong Kong Society for Relief of Disabled Children and Jeffrey Modell Foundation.http://www.frontiersin.org/Immunologyam2023Paediatrics and Child Healt

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

High-speed rail operations on an existing network: an assessment model for China

High-speed rail operations have the potential to reduce the long-term decline in rail passenger travel demand for the medium to long distance inter-urban markets. Such decline has been evident through most of the industrialized countries where air and road transport tend to be the dominant modes. In China, the operations of long distance high-speed rail on fully dedicated track is not very easy to implement, due to the high proportion of passengers who travel between high-speed and conventional railways. An alternative approach would be to allow for mixed operations with trains of various speeds on the same track. This paper puts forward a simulation model designed to allow an evaluation of the most efficient distance for high-speed rail operations under mixed train speed scenarios. The model takes into account the main operating parameters such as passenger volumes, train speeds, capital and maintenance costs, train operating costs and energy consumption. The distance of high-speed train running on conventional rail, that will yield the most economic benefit, can be estimated using the model. The paper shows the results of using the model for a specific example. It is concluded that large-scale high-speed trains have the potential to be successfully operated on conventional rail networks

Analysis of the effect of wax content on bitumen under performance grade classification

This paper describes an analysis of the effect of wax content on bitumen under performance grade (PG) classification. Wax content affects the performance and rheological behavior of bitumen. Bituminous mixtures with bitumen of high wax content tend to become very soft at high temperatures leading to rutting problem on pavement. Also the rheological behavior of bitumen has a great influence on the behavior of bituminous mixtures. To address the potential adverse effect of wax on bitumen, countries in Europe limit the wax content to 2.2% (BS EN 12606-1). In Mainland China, the standard (JTG F40-2004) classifies bitumen into three grades (Grades A, B and C). Grade A, with wax content below 2.2%, is used for highway pavement construction. Grades B and C, with wax content limits of 3.0% and 4.5% respectively, can only be used on roads with relatively lower traffic. The current binder specifications in Hong Kong Special Administration Region is based on penetration testing, which does not properly account for pavement performance. This paper assesses the effects of wax content and the rheological properties of seven types of bitumens and provides the basis for a performance grading binder standard for Hong Kong

Gray evaluation method of concrete pavement comprehensive condition

Evaluation of pavement condition is important in a pavement management system. In the existing evaluation methods, systematic analysis and regression modeling analysis are often used. But the former relies more on experienced judgment and the latter is restrained to use by the territory condition. For pavement evaluation, some data or properties relating to the environment and structure may not be very clear, and so the pavement system is gray in its nature. By applying the gray sole characteristic principle of the gray system theory, a comprehensive condition evaluation can be completed under partial data circumstances. In this paper, the principles used in the evaluation and selection of indexes are presented. In view of the gray characteristics of the pavement system, a set of comprehensive evaluating methods for concrete pavement organically combining the single indexes and a comprehensive index is presented. Dimensionless treatment is used to deal with the data, types of gray weight functions and their thresholds are determined, the gray weight function of each index when it belongs to a different gray class is introduced and deduced, and a general algorithm of the comprehensive condition evaluation is presented. Evaluations of various sections in a highway are carried out and compared

Study on improved ploypropylene modified bitumen by incorporating phosphoric acid

This study presents a research conducted to investigate the properties of polymer modified bitumen (PMB) by using bitumen 60/70 as original bitumen, polypropylene (PP) as modifier, phosphoric acid (H3PO4) as additives, and with wet mixing method combining high shear mix and low shear mix in order to determine the optimum binder-PP ratio PMB for applying in Hong Kong. 18 samples had been prepared in this study, of which the PP contents vary from 2~7% with 1%, 3% and 5% of H3PO4 content. In result, compatibility and stability between PP and bitumen is the control factor for determining the maximum content of PP that can be added into the PMB, and all the PMB sample resulted in better performance in every test conducted in this study except ductility. It is concluded that the optimum binder-PP ratio in terms of upgrading the original bitumen (bitumen 60/70) to grade PG82 for Hong Kong areas is 5% PP with 3% H3PO4

Prediction of resilient modulus of compacted saprolitic soils by CBR approach for road pavement subgrade: a re-examination

The scope of the study as presented in this paper is to re-examine the prediction of resilient modulus (M R) by the classical California Bearing Ratio (CBR) approach, specifically for compacted saprolitic subgrade soils. Through the extensive experiments carried out for this research, a more precise model yielded to estimate M R based on CBR values and the relative degrees of soil compaction. Likewise, comments are also made critically for the suitability of using the well-known models which were developed during the past decades. In addition to the core results, this study has produced a number of other important findings: (1) the influence of soil compaction densities on CBR and M R is relatively significant when soil is relatively dry, whereas saturation ratio becomes a dominant factor while the soil is in wetter condition; (2) when the saturation ratio becomes dominant, the soil material could rarely reach a CBR of 5% or above, which was often regarded as competent materials by many design standards; (3) the moisture ratio (R m) of the saprolitic subgrade materials is one of the useful parameters in estimating M R and (4) the distinctive behaviours of saprolitic subgrade soils under CBR, unconfined compressive strength and repeated load tests are considered to be related to the degree of freedom of volume change for soil samples during the tests

Evaluation of fatigue crack behavior in asphalt concrete pavements with different polymer modifiers

Fatigue crack has been recognized as one of the main forms for structural damage in asphalt concrete pavements. Under the action of repeated vehicular loading, deterioration of the asphalt concrete (AC) materials in pavements, caused by the accumulation and growth of micro and macro cracks, gradually takes place. Existing prediction models in asphalt concrete pavement typically do not take the interaction and dependencies between micro and macro mechanics into account. In this research, the fatigue damage models and failure criteria are established based on the Indirect Tensile Fatigue Tests (ITFT) and Indirect Tensile Stiffness Modulus (ITSM) tests carried out on AC materials with different kinds of polymer modifiers. These additives are Polypropylene (PP), Crumb rubber (CR), Cellulose fiber (CF), Asbestos fiber (AF) and Gilsonite (GS). Fatigue damage model, based on continuum damage mechanics, describes the formation of micro-cracks and crack propagation developed in the wearing course materials (ACWC and SMA). With the fatigue damage models, finite element analysis is carried out to study the crack resisting performance of the wearing course materials in a flexible pavement structure